NEWS
author haftmann
Mon Nov 10 19:42:22 2008 +0100 (2008-11-10)
changeset 28734 19277c7a160c
parent 28710 e2064974c114
child 28741 1b257449f804
permissions -rw-r--r--
restruced naming code in anticipation of introduction of name morphisms
     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 element "includes".  This is a major INCOMPATIBILITY.
    81 In existing theorem specifications replace the includes element by the
    82 respective context elements of the included locale, omitting those that
    83 are already present in the theorem specification.  Multiple assume
    84 elements of a locale should be replaced by a single one involving the
    85 locale predicate.  In the proof body, declarations (most notably
    86 theorems) may be regained by interpreting the respective locales in the
    87 proof context as required (command "interpret").
    88 If using "includes" in replacement of a target solely because the
    89 parameter types in the theorem are not as general as in the target,
    90 consider declaring a new locale with additional type constraints on the
    91 parameters (context element "constrains").
    92 
    93 * Dropped "locale (open)".  INCOMPATBILITY.
    94 
    95 * Interpretation commands no longer attempt to simplify goal.
    96 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
    97 methods intro_locales and unfold_locales to clarify.
    98 
    99 * Interpretation commands no longer accept interpretation attributes.
   100 INCOMPATBILITY.
   101 
   102 * Command 'instance': attached definitions no longer accepted.
   103 INCOMPATIBILITY, use proper 'instantiation' target.
   104 
   105 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   106 
   107 * The 'axiomatization' command now only works within a global theory
   108 context.  INCOMPATIBILITY.
   109 
   110 
   111 *** Document preparation ***
   112 
   113 * Antiquotation @{lemma} now imitates a regular terminal proof,
   114 demanding keyword 'by' and supporting the full method expression
   115 syntax just like the Isar command 'by'.
   116 
   117 
   118 *** HOL ***
   119 
   120 * New classes "top" and "bot" with corresponding operations "top" and "bot"
   121 in theory Orderings;  instantiation of class "complete_lattice" requires
   122 instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   123 
   124 * Changed definition lemma "less_fun_def" in order to provide an instance
   125 for preorders on functions;  use lemma "less_le" instead.  INCOMPATIBILITY.
   126 
   127 * Unified theorem tables for both code code generators.  Thus
   128 [code func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   129 
   130 * Constants "undefined" and "default" replace "arbitrary".  Usually
   131 "undefined" is the right choice to replace "arbitrary", though logically
   132 there is no difference.  INCOMPATIBILITY.
   133 
   134 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   135 Posix processes.  Avoids potentially expensive forking of the ML
   136 process.  New thread-based implementation also works on non-Unix
   137 platforms (Cygwin).  Provers are no longer hardwired, but defined
   138 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   139 commands are covered in the isar-ref manual
   140 
   141 * Wrapper scripts for remote SystemOnTPTP service allows to use
   142 sledgehammer without local ATP installation (Vampire etc.).  See also
   143 ISABELLE_HOME/contrib/SystemOnTPTP and the VAMPIRE_HOME setting
   144 variable.  Other provers may be included via suitable ML wrappers, see
   145 also src/HOL/ATP_Linkup.thy.
   146 
   147 * Normalization by evaluation now allows non-leftlinear equations.
   148 Declare with attribute [code nbe].
   149 
   150 * Command "value" now integrates different evaluation
   151 mechanisms.  The result of the first successful evaluation mechanism
   152 is printed.  In square brackets a particular named evaluation
   153 mechanisms may be specified (currently, [SML], [code] or [nbe]).  See
   154 further src/HOL/ex/Eval_Examples.thy.
   155 
   156 * HOL/Orderings: class "wellorder" moved here, with explicit induction
   157 rule "less_induct" as assumption.  For instantiation of "wellorder" by
   158 means of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.
   159 
   160 * HOL/Orderings: added class "preorder" as superclass of "order".
   161 INCOMPATIBILITY: Instantiation proofs for order, linorder
   162 etc. slightly changed.  Some theorems named order_class.* now named
   163 preorder_class.*.
   164 
   165 * HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
   166 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   167 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   168 of lemmas from Divides has been generalized from nat to class
   169 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   170 renames resulting from duplicate elimination:
   171 
   172     dvd_def_mod ~>          dvd_eq_mod_eq_0
   173     zero_dvd_iff ~>         dvd_0_left_iff
   174     dvd_0 ~>                dvd_0_right
   175     DIVISION_BY_ZERO_DIV ~> div_by_0
   176     DIVISION_BY_ZERO_MOD ~> mod_by_0
   177     mult_div ~>             div_mult_self2_is_id
   178     mult_mod ~>             mod_mult_self2_is_0
   179 
   180 * HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   181 zlcm (for int); carried together from various gcd/lcm developements in
   182 the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
   183 corresponding theorems renamed accordingly.  INCOMPATIBILY.  To
   184 recover tupled syntax, use syntax declarations like:
   185 
   186     hide (open) const gcd
   187     abbreviation gcd where
   188       "gcd == (%(a, b). GCD.gcd a b)"
   189     notation (output)
   190       GCD.gcd ("gcd '(_, _')")
   191 
   192 (analogously for lcm, zgcd, zlcm).
   193 
   194 * HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   195 
   196 * New ML antiquotation @{code}: takes constant as argument, generates
   197 corresponding code in background and inserts name of the corresponding
   198 resulting ML value/function/datatype constructor binding in place.
   199 All occurrences of @{code} with a single ML block are generated
   200 simultaneously.  Provides a generic and safe interface for
   201 instrumentalizing code generation.  See HOL/ex/Code_Antiq for a toy
   202 example, or HOL/Complex/ex/ReflectedFerrack for a more ambitious
   203 application.  In future you ought refrain from ad-hoc compiling
   204 generated SML code on the ML toplevel.  Note that (for technical
   205 reasons) @{code} cannot refer to constants for which user-defined
   206 serializations are set.  Refer to the corresponding ML counterpart
   207 directly in that cases.
   208 
   209 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   210 Complex_Main.thy remain as they are.
   211 
   212 * New image HOL-Plain provides a minimal HOL with the most important
   213 tools available (inductive, datatype, primrec, ...).  By convention
   214 the corresponding theory Plain should be ancestor of every further
   215 (library) theory.  Some library theories now have ancestor Plain
   216 (instead of Main), thus theory Main occasionally has to be imported
   217 explicitly.
   218 
   219 * The metis method now fails in the usual manner, rather than raising
   220 an exception, if it determines that it cannot prove the theorem.
   221 
   222 * The metis method no longer fails because the theorem is too trivial
   223 (contains the empty clause).
   224 
   225 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   226 as the structured Isar versions "cases" and "induct", cf. the
   227 corresponding "cases" and "induct" attributes.  Mutual induction rules
   228 are now presented as a list of individual projections
   229 (e.g. foo_bar.inducts for types foo and bar); the old format with
   230 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   231 rare situations a different rule is selected --- notably nested tuple
   232 elimination instead of former prod.exhaust: use explicit (case_tac t
   233 rule: prod.exhaust) here.
   234 
   235 * Attributes "cases", "induct", "coinduct" support "del" option.
   236 
   237 * Removed fact "case_split_thm", which duplicates "case_split".
   238 
   239 * Command 'rep_datatype': instead of theorem names the command now
   240 takes a list of terms denoting the constructors of the type to be
   241 represented as datatype.  The characteristic theorems have to be
   242 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   243 have disappeared in favour of existing ones:
   244 
   245     unit_induct                 ~> unit.induct
   246     prod_induct                 ~> prod.induct
   247     sum_induct                  ~> sum.induct
   248     Suc_Suc_eq                  ~> nat.inject
   249     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   250 
   251 * Library/Nat_Infinity: added addition, numeral syntax and more
   252 instantiations for algebraic structures.  Removed some duplicate
   253 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   254 
   255 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   256 menu.
   257 
   258 
   259 *** HOL-Algebra ***
   260 
   261 * New locales for orders and lattices where the equivalence relation
   262   is not restricted to equality.  INCOMPATIBILITY: all order and
   263   lattice locales use a record structure with field eq for the
   264   equivalence.
   265 
   266 * New theory of factorial domains.
   267 
   268 * Units_l_inv and Units_r_inv are now simprules by default.
   269 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   270 and/or r_inv will now also require deletion of these lemmas.
   271 
   272 * Renamed the following theorems.  INCOMPATIBILITY.
   273 UpperD ~> Upper_memD
   274 LowerD ~> Lower_memD
   275 least_carrier ~> least_closed
   276 greatest_carrier ~> greatest_closed
   277 greatest_Lower_above ~> greatest_Lower_below
   278 one_zero ~> carrier_one_zero
   279 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   280 
   281 
   282 *** HOL-NSA ***
   283 
   284 * Created new image HOL-NSA, containing theories of nonstandard
   285 analysis which were previously part of HOL-Complex.  Entry point
   286 Hyperreal.thy remains valid, but theories formerly using
   287 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   288 
   289 
   290 *** ZF ***
   291 
   292 * Proof of Zorn's Lemma for partial orders.
   293 
   294 
   295 *** ML ***
   296 
   297 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   298 to 'a -> thm, while results are always tagged with an authentic oracle
   299 name.  The Isar command 'oracle' is now polymorphic, no argument type
   300 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   301 accordingly.  Note that extra performance may be gained by producing
   302 the cterm carefully, avoiding slow Thm.cterm_of.
   303 
   304 * ML bindings produced via Isar commands are stored within the Isar
   305 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   306 become thread-safe and work with undo as expected (concerning
   307 top-level bindings, not side-effects on global references).
   308 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   309 compiler at runtime; really global bindings need to be given outside a
   310 theory. [Poly/ML 5.2 or later]
   311 
   312 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   313 context. Top-level ML bindings are stored within the proof context in
   314 a purely sequential fashion, disregarding the nested proof structure.
   315 ML bindings introduced by 'ML_prf' are discarded at the end of the
   316 proof.  [Poly/ML 5.2 or later]
   317 
   318 * Generic Toplevel.add_hook interface allows to analyze the result of
   319 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   320 for theorem dependency output of transactions resulting in a new
   321 theory state.
   322 
   323 * Name bindings in higher specification mechanisms (notably
   324 LocalTheory.define, LocalTheory.note, and derived packages) are now
   325 formalized as type Name.binding, replacing old bstring.
   326 INCOMPATIBILITY, need to wrap strings via Name.binding function, see
   327 also Name.name_of.  Packages should pass name bindings given by the
   328 user to underlying specification mechanisms; this enables precise
   329 tracking of source positions, for example.
   330 
   331 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   332 LocalTheory.note etc.) now refer to the *full* internal name, not the
   333 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   334 
   335 * Rules and tactics that read instantiations (read_instantiate,
   336 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   337 context, which is required for parsing and type-checking.  Moreover,
   338 the variables are specified as plain indexnames, not string encodings
   339 thereof.  INCOMPATIBILITY.
   340 
   341 * Disposed old type and term read functions (Sign.read_def_typ,
   342 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   343 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   344 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   345 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   346 resort for legacy applications.
   347 
   348 * Antiquotations: block-structured compilation context indicated by
   349 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   350 
   351   @{let ?pat = term}                      - term abbreviation (HO matching)
   352   @{note name = fact}                     - fact abbreviation
   353   @{thm fact}                             - singleton fact (with attributes)
   354   @{thms fact}                            - general fact (with attributes)
   355   @{lemma prop by method}                 - singleton goal
   356   @{lemma prop by meth1 meth2}            - singleton goal
   357   @{lemma prop1 ... propN by method}      - general goal
   358   @{lemma prop1 ... propN by meth1 meth2} - general goal
   359   @{lemma (open) ...}                     - open derivation
   360 
   361 
   362 *** System ***
   363 
   364 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   365 Poly/ML 5.2.1 or later.
   366 
   367 * The Isabelle "emacs" tool provides a specific interface to invoke
   368 Proof General / Emacs, with more explicit failure if that is not
   369 installed (the old isabelle-interface script silently falls back on
   370 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   371 installation location of the Proof General distribution.
   372 
   373 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   374 the Isabelle process into a JVM/Scala application.  See
   375 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   376 process wrapper has been discontinued.)
   377 
   378 * Status messages (with exact source position information) are
   379 emitted, if proper markup print mode is enabled.  This allows
   380 user-interface components to provide detailed feedback on internal
   381 prover operations.
   382 
   383 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   384 
   385 
   386 
   387 New in Isabelle2008 (June 2008)
   388 -------------------------------
   389 
   390 *** General ***
   391 
   392 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   393 and updated, with formally checked references as hyperlinks.
   394 
   395 * Theory loader: use_thy (and similar operations) no longer set the
   396 implicit ML context, which was occasionally hard to predict and in
   397 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   398 provides a proper context already.
   399 
   400 * Theory loader: old-style ML proof scripts being *attached* to a thy
   401 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   402 'use' within a theory file will do the job.
   403 
   404 * Name space merge now observes canonical order, i.e. the second space
   405 is inserted into the first one, while existing entries in the first
   406 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   407 swap theory imports.
   408 
   409 * Syntax: symbol \<chi> is now considered a letter.  Potential
   410 INCOMPATIBILITY in identifier syntax etc.
   411 
   412 * Outer syntax: string tokens no longer admit escaped white space,
   413 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   414 white space without escapes.
   415 
   416 * Outer syntax: string tokens may contain arbitrary character codes
   417 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   418 "foo_bar".
   419 
   420 
   421 *** Pure ***
   422 
   423 * Context-dependent token translations.  Default setup reverts locally
   424 fixed variables, and adds hilite markup for undeclared frees.
   425 
   426 * Unused theorems can be found using the new command 'unused_thms'.
   427 There are three ways of invoking it:
   428 
   429 (1) unused_thms
   430      Only finds unused theorems in the current theory.
   431 
   432 (2) unused_thms thy_1 ... thy_n -
   433      Finds unused theorems in the current theory and all of its ancestors,
   434      excluding the theories thy_1 ... thy_n and all of their ancestors.
   435 
   436 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   437      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   438      their ancestors, excluding the theories thy_1 ... thy_n and all of
   439      their ancestors.
   440 
   441 In order to increase the readability of the list produced by
   442 unused_thms, theorems that have been created by a particular instance
   443 of a theory command such as 'inductive' or 'function' are considered
   444 to belong to the same "group", meaning that if at least one theorem in
   445 this group is used, the other theorems in the same group are no longer
   446 reported as unused.  Moreover, if all theorems in the group are
   447 unused, only one theorem in the group is displayed.
   448 
   449 Note that proof objects have to be switched on in order for
   450 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   451 usually the case when using Proof General with the default settings).
   452 
   453 * Authentic naming of facts disallows ad-hoc overwriting of previous
   454 theorems within the same name space.  INCOMPATIBILITY, need to remove
   455 duplicate fact bindings, or even accidental fact duplications.  Note
   456 that tools may maintain dynamically scoped facts systematically, using
   457 PureThy.add_thms_dynamic.
   458 
   459 * Command 'hide' now allows to hide from "fact" name space as well.
   460 
   461 * Eliminated destructive theorem database, simpset, claset, and
   462 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   463 update of theories within ML code.
   464 
   465 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   466 INCOMPATIBILITY, object-logics depending on former Pure require
   467 additional setup PureThy.old_appl_syntax_setup; object-logics
   468 depending on former CPure need to refer to Pure.
   469 
   470 * Commands 'use' and 'ML' are now purely functional, operating on
   471 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   472 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   473 INCOMPATIBILITY.
   474 
   475 * Command 'setup': discontinued implicit version with ML reference.
   476 
   477 * Instantiation target allows for simultaneous specification of class
   478 instance operations together with an instantiation proof.
   479 Type-checking phase allows to refer to class operations uniformly.
   480 See src/HOL/Complex/Complex.thy for an Isar example and
   481 src/HOL/Library/Eval.thy for an ML example.
   482 
   483 * Indexing of literal facts: be more serious about including only
   484 facts from the visible specification/proof context, but not the
   485 background context (locale etc.).  Affects `prop` notation and method
   486 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   487 situations.
   488 
   489 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   490 "(open)" option, which used to expose internal bound variables to the
   491 proof text.
   492 
   493 * Isar statements: removed obsolete case "rule_context".
   494 INCOMPATIBILITY, better use explicit fixes/assumes.
   495 
   496 * Locale proofs: default proof step now includes 'unfold_locales';
   497 hence 'proof' without argument may be used to unfold locale
   498 predicates.
   499 
   500 
   501 *** Document preparation ***
   502 
   503 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   504 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   505 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   506 spot); renamed link color from "darkblue" to "linkcolor" (default
   507 value unchanged, can be redefined via \definecolor); no longer sets
   508 "a4paper" option (unnecessary or even intrusive).
   509 
   510 * Antiquotation @{lemma A method} proves proposition A by the given
   511 method (either a method name or a method name plus (optional) method
   512 arguments in parentheses) and prints A just like @{prop A}.
   513 
   514 
   515 *** HOL ***
   516 
   517 * New primrec package.  Specification syntax conforms in style to
   518 definition/function/....  No separate induction rule is provided.  The
   519 "primrec" command distinguishes old-style and new-style specifications
   520 by syntax.  The former primrec package is now named OldPrimrecPackage.
   521 When adjusting theories, beware: constants stemming from new-style
   522 primrec specifications have authentic syntax.
   523 
   524 * Metis prover is now an order of magnitude faster, and also works
   525 with multithreading.
   526 
   527 * Metis: the maximum number of clauses that can be produced from a
   528 theorem is now given by the attribute max_clauses.  Theorems that
   529 exceed this number are ignored, with a warning printed.
   530 
   531 * Sledgehammer no longer produces structured proofs by default. To
   532 enable, declare [[sledgehammer_full = true]].  Attributes
   533 reconstruction_modulus, reconstruction_sorts renamed
   534 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   535 
   536 * Method "induct_scheme" derives user-specified induction rules
   537 from well-founded induction and completeness of patterns. This factors
   538 out some operations that are done internally by the function package
   539 and makes them available separately.  See
   540 src/HOL/ex/Induction_Scheme.thy for examples.
   541 
   542 * More flexible generation of measure functions for termination
   543 proofs: Measure functions can be declared by proving a rule of the
   544 form "is_measure f" and giving it the [measure_function] attribute.
   545 The "is_measure" predicate is logically meaningless (always true), and
   546 just guides the heuristic.  To find suitable measure functions, the
   547 termination prover sets up the goal "is_measure ?f" of the appropriate
   548 type and generates all solutions by prolog-style backwards proof using
   549 the declared rules.
   550 
   551 This setup also deals with rules like 
   552 
   553   "is_measure f ==> is_measure (list_size f)"
   554 
   555 which accommodates nested datatypes that recurse through lists.
   556 Similar rules are predeclared for products and option types.
   557 
   558 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   559 
   560   INCOMPATIBILITIES:
   561 
   562   - Definitions of overloaded constants on sets have to be replaced by
   563     definitions on => and bool.
   564 
   565   - Some definitions of overloaded operators on sets can now be proved
   566     using the definitions of the operators on => and bool.  Therefore,
   567     the following theorems have been renamed:
   568 
   569       subset_def   -> subset_eq
   570       psubset_def  -> psubset_eq
   571       set_diff_def -> set_diff_eq
   572       Compl_def    -> Compl_eq
   573       Sup_set_def  -> Sup_set_eq
   574       Inf_set_def  -> Inf_set_eq
   575       sup_set_def  -> sup_set_eq
   576       inf_set_def  -> inf_set_eq
   577 
   578   - Due to the incompleteness of the HO unification algorithm, some
   579     rules such as subst may require manual instantiation, if some of
   580     the unknowns in the rule is a set.
   581 
   582   - Higher order unification and forward proofs:
   583     The proof pattern
   584 
   585       have "P (S::'a set)" <...>
   586       then have "EX S. P S" ..
   587 
   588     no longer works (due to the incompleteness of the HO unification
   589     algorithm) and must be replaced by the pattern
   590 
   591       have "EX S. P S"
   592       proof
   593         show "P S" <...>
   594       qed
   595 
   596   - Calculational reasoning with subst (or similar rules):
   597     The proof pattern
   598 
   599       have "P (S::'a set)" <...>
   600       also have "S = T" <...>
   601       finally have "P T" .
   602 
   603     no longer works (for similar reasons as the previous example) and
   604     must be replaced by something like
   605 
   606       have "P (S::'a set)" <...>
   607       moreover have "S = T" <...>
   608       ultimately have "P T" by simp
   609 
   610   - Tactics or packages written in ML code:
   611     Code performing pattern matching on types via
   612 
   613       Type ("set", [T]) => ...
   614 
   615     must be rewritten. Moreover, functions like strip_type or
   616     binder_types no longer return the right value when applied to a
   617     type of the form
   618 
   619       T1 => ... => Tn => U => bool
   620 
   621     rather than
   622 
   623       T1 => ... => Tn => U set
   624 
   625 * Merged theories Wellfounded_Recursion, Accessible_Part and
   626 Wellfounded_Relations to theory Wellfounded.
   627 
   628 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   629 
   630 * Class finite no longer treats UNIV as class parameter.  Use class
   631 enum from theory Library/Enum instead to achieve a similar effect.
   632 INCOMPATIBILITY.
   633 
   634 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   635 and "Cons".  INCOMPATIBILITY.
   636 
   637 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   638 Potential INCOMPATIBILITY.
   639 
   640 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   641 injective_fst_snd removed, use split_eta and prod_eqI instead.
   642 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   643 
   644 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   645 the same name in theory Orderings:
   646 
   647   less_trans
   648   less_linear
   649   le_imp_less_or_eq
   650   le_less_trans
   651   less_le_trans
   652   less_not_sym
   653   less_asym
   654 
   655 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
   656 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
   657 and different variable names.
   658 
   659 * Library/Option_ord.thy: Canonical order on option type.
   660 
   661 * Library/RBT.thy: Red-black trees, an efficient implementation of
   662 finite maps.
   663 
   664 * Library/Countable.thy: Type class for countable types.
   665 
   666 * Theory Int: The representation of numerals has changed.  The infix
   667 operator BIT and the bit datatype with constructors B0 and B1 have
   668 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
   669 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
   670 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
   671 accordingly.
   672 
   673 * Theory Nat: definition of <= and < on natural numbers no longer
   674 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
   675 le_def and less_def have disappeared.  Consider lemmas not_less
   676 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
   677 
   678 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
   679 (whose purpose mainly is for various fold_set functionals) have been
   680 abandoned in favor of the existing algebraic classes
   681 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
   682 lower_semilattice (resp. upper_semilattice) and linorder.
   683 INCOMPATIBILITY.
   684 
   685 * Theory Transitive_Closure: induct and cases rules now declare proper
   686 case_names ("base" and "step").  INCOMPATIBILITY.
   687 
   688 * Theorem Inductive.lfp_ordinal_induct generalized to complete
   689 lattices.  The form set-specific version is available as
   690 Inductive.lfp_ordinal_induct_set.
   691 
   692 * Renamed theorems "power.simps" to "power_int.simps".
   693 INCOMPATIBILITY.
   694 
   695 * Class semiring_div provides basic abstract properties of semirings
   696 with division and modulo operations.  Subsumes former class dvd_mod.
   697 
   698 * Merged theories IntDef, Numeral and IntArith into unified theory
   699 Int.  INCOMPATIBILITY.
   700 
   701 * Theory Library/Code_Index: type "index" now represents natural
   702 numbers rather than integers.  INCOMPATIBILITY.
   703 
   704 * New class "uminus" with operation "uminus" (split of from class
   705 "minus" which now only has operation "minus", binary).
   706 INCOMPATIBILITY.
   707 
   708 * Constants "card", "internal_split", "option_map" now with authentic
   709 syntax.  INCOMPATIBILITY.
   710 
   711 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
   712 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
   713 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
   714 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
   715 Sup_set_def, le_def, less_def, option_map_def now with object
   716 equality.  INCOMPATIBILITY.
   717 
   718 * Records. Removed K_record, and replaced it by pure lambda term
   719 %x. c. The simplifier setup is now more robust against eta expansion.
   720 INCOMPATIBILITY: in cases explicitly referring to K_record.
   721 
   722 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
   723 
   724 * Library/ListVector: new theory of arithmetic vector operations.
   725 
   726 * Library/Order_Relation: new theory of various orderings as sets of
   727 pairs.  Defines preorders, partial orders, linear orders and
   728 well-orders on sets and on types.
   729 
   730 
   731 *** ZF ***
   732 
   733 * Renamed some theories to allow to loading both ZF and HOL in the
   734 same session:
   735 
   736   Datatype  -> Datatype_ZF
   737   Inductive -> Inductive_ZF
   738   Int       -> Int_ZF
   739   IntDiv    -> IntDiv_ZF
   740   Nat       -> Nat_ZF
   741   List      -> List_ZF
   742   Main      -> Main_ZF
   743 
   744 INCOMPATIBILITY: ZF theories that import individual theories below
   745 Main might need to be adapted.  Regular theory Main is still
   746 available, as trivial extension of Main_ZF.
   747 
   748 
   749 *** ML ***
   750 
   751 * ML within Isar: antiquotation @{const name} or @{const
   752 name(typargs)} produces statically-checked Const term.
   753 
   754 * Functor NamedThmsFun: data is available to the user as dynamic fact
   755 (of the same name).  Removed obsolete print command.
   756 
   757 * Removed obsolete "use_legacy_bindings" function.
   758 
   759 * The ``print mode'' is now a thread-local value derived from a global
   760 template (the former print_mode reference), thus access becomes
   761 non-critical.  The global print_mode reference is for session
   762 management only; user-code should use print_mode_value,
   763 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
   764 
   765 * Functions system/system_out provide a robust way to invoke external
   766 shell commands, with propagation of interrupts (requires Poly/ML 5.2).
   767 Do not use OS.Process.system etc. from the basis library!
   768 
   769 
   770 *** System ***
   771 
   772 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
   773 in accordance with Proof General 3.7, which prefers GNU emacs.
   774 
   775 * isatool tty runs Isabelle process with plain tty interaction;
   776 optional line editor may be specified via ISABELLE_LINE_EDITOR
   777 setting, the default settings attempt to locate "ledit" and "rlwrap".
   778 
   779 * isatool browser now works with Cygwin as well, using general
   780 "javapath" function defined in Isabelle process environment.
   781 
   782 * YXML notation provides a simple and efficient alternative to
   783 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
   784 isatool yxml as described in the Isabelle system manual.
   785 
   786 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
   787 provides general wrapper for managing an Isabelle process in a robust
   788 fashion, with ``cooked'' output from stdin/stderr.
   789 
   790 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
   791 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
   792 
   793 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
   794 way of changing the user's settings is via
   795 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
   796 script.
   797 
   798 * Multithreading.max_threads := 0 refers to the number of actual CPU
   799 cores of the underlying machine, which is a good starting point for
   800 optimal performance tuning.  The corresponding usedir option -M allows
   801 "max" as an alias for "0".  WARNING: does not work on certain versions
   802 of Mac OS (with Poly/ML 5.1).
   803 
   804 * isabelle-process: non-ML sessions are run with "nice", to reduce the
   805 adverse effect of Isabelle flooding interactive front-ends (notably
   806 ProofGeneral / XEmacs).
   807 
   808 
   809 
   810 New in Isabelle2007 (November 2007)
   811 -----------------------------------
   812 
   813 *** General ***
   814 
   815 * More uniform information about legacy features, notably a
   816 warning/error of "Legacy feature: ...", depending on the state of the
   817 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
   818 legacy features will disappear eventually.
   819 
   820 * Theory syntax: the header format ``theory A = B + C:'' has been
   821 discontinued in favour of ``theory A imports B C begin''.  Use isatool
   822 fixheaders to convert existing theory files.  INCOMPATIBILITY.
   823 
   824 * Theory syntax: the old non-Isar theory file format has been
   825 discontinued altogether.  Note that ML proof scripts may still be used
   826 with Isar theories; migration is usually quite simple with the ML
   827 function use_legacy_bindings.  INCOMPATIBILITY.
   828 
   829 * Theory syntax: some popular names (e.g. 'class', 'declaration',
   830 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
   831 quotes.
   832 
   833 * Theory loader: be more serious about observing the static theory
   834 header specifications (including optional directories), but not the
   835 accidental file locations of previously successful loads.  The strict
   836 update policy of former update_thy is now already performed by
   837 use_thy, so the former has been removed; use_thys updates several
   838 theories simultaneously, just as 'imports' within a theory header
   839 specification, but without merging the results.  Potential
   840 INCOMPATIBILITY: may need to refine theory headers and commands
   841 ROOT.ML which depend on load order.
   842 
   843 * Theory loader: optional support for content-based file
   844 identification, instead of the traditional scheme of full physical
   845 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
   846 (cf. the system manual).  The new scheme allows to work with
   847 non-finished theories in persistent session images, such that source
   848 files may be moved later on without requiring reloads.
   849 
   850 * Theory loader: old-style ML proof scripts being *attached* to a thy
   851 file (with the same base name as the theory) are considered a legacy
   852 feature, which will disappear eventually. Even now, the theory loader
   853 no longer maintains dependencies on such files.
   854 
   855 * Syntax: the scope for resolving ambiguities via type-inference is
   856 now limited to individual terms, instead of whole simultaneous
   857 specifications as before. This greatly reduces the complexity of the
   858 syntax module and improves flexibility by separating parsing and
   859 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
   860 'fixes' etc.) are required in rare situations.
   861 
   862 * Syntax: constants introduced by new-style packages ('definition',
   863 'abbreviation' etc.) are passed through the syntax module in
   864 ``authentic mode''. This means that associated mixfix annotations
   865 really stick to such constants, independently of potential name space
   866 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
   867 trees are represented slightly differently, may need to adapt syntax
   868 translations accordingly. Use CONST marker in 'translations' and
   869 @{const_syntax} antiquotation in 'parse_translation' etc.
   870 
   871 * Legacy goal package: reduced interface to the bare minimum required
   872 to keep existing proof scripts running.  Most other user-level
   873 functions are now part of the OldGoals structure, which is *not* open
   874 by default (consider isatool expandshort before open OldGoals).
   875 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
   876 these tend to cause confusion about the actual goal (!) context being
   877 used here, which is not necessarily the same as the_context().
   878 
   879 * Command 'find_theorems': supports "*" wild-card in "name:"
   880 criterion; "with_dups" option.  Certain ProofGeneral versions might
   881 support a specific search form (see ProofGeneral/CHANGES).
   882 
   883 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
   884 by default, which means that "prems" (and also "fixed variables") are
   885 suppressed from proof state output.  Note that the ProofGeneral
   886 settings mechanism allows to change and save options persistently, but
   887 older versions of Isabelle will fail to start up if a negative prems
   888 limit is imposed.
   889 
   890 * Local theory targets may be specified by non-nested blocks of
   891 ``context/locale/class ... begin'' followed by ``end''.  The body may
   892 contain definitions, theorems etc., including any derived mechanism
   893 that has been implemented on top of these primitives.  This concept
   894 generalizes the existing ``theorem (in ...)'' towards more versatility
   895 and scalability.
   896 
   897 * Proof General interface: proper undo of final 'end' command;
   898 discontinued Isabelle/classic mode (ML proof scripts).
   899 
   900 
   901 *** Document preparation ***
   902 
   903 * Added antiquotation @{theory name} which prints the given name,
   904 after checking that it refers to a valid ancestor theory in the
   905 current context.
   906 
   907 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   908 check the given source text as ML type/structure, printing verbatim.
   909 
   910 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   911 "c args == rhs" given in the current context.  (Any number of
   912 arguments may be given on the LHS.)
   913 
   914 
   915 *** Pure ***
   916 
   917 * The 'class' package offers a combination of axclass and locale to
   918 achieve Haskell-like type classes in Isabelle.  Definitions and
   919 theorems within a class context produce both relative results (with
   920 implicit parameters according to the locale context), and polymorphic
   921 constants with qualified polymorphism (according to the class
   922 context).  Within the body context of a 'class' target, a separate
   923 syntax layer ("user space type system") takes care of converting
   924 between global polymorphic consts and internal locale representation.
   925 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   926 "isatool doc classes" provides a tutorial.
   927 
   928 * Generic code generator framework allows to generate executable
   929 code for ML and Haskell (including Isabelle classes).  A short usage
   930 sketch:
   931 
   932     internal compilation:
   933         export_code <list of constants (term syntax)> in SML
   934     writing SML code to a file:
   935         export_code <list of constants (term syntax)> in SML <filename>
   936     writing OCaml code to a file:
   937         export_code <list of constants (term syntax)> in OCaml <filename>
   938     writing Haskell code to a bunch of files:
   939         export_code <list of constants (term syntax)> in Haskell <filename>
   940 
   941     evaluating closed propositions to True/False using code generation:
   942         method ``eval''
   943 
   944 Reasonable default setup of framework in HOL.
   945 
   946 Theorem attributs for selecting and transforming function equations theorems:
   947 
   948     [code fun]:        select a theorem as function equation for a specific constant
   949     [code fun del]:    deselect a theorem as function equation for a specific constant
   950     [code inline]:     select an equation theorem for unfolding (inlining) in place
   951     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   952 
   953 User-defined serializations (target in {SML, OCaml, Haskell}):
   954 
   955     code_const <and-list of constants (term syntax)>
   956       {(target) <and-list of const target syntax>}+
   957 
   958     code_type <and-list of type constructors>
   959       {(target) <and-list of type target syntax>}+
   960 
   961     code_instance <and-list of instances>
   962       {(target)}+
   963         where instance ::= <type constructor> :: <class>
   964 
   965     code_class <and_list of classes>
   966       {(target) <and-list of class target syntax>}+
   967         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   968 
   969 code_instance and code_class only are effective to target Haskell.
   970 
   971 For example usage see src/HOL/ex/Codegenerator.thy and
   972 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   973 generation from Isabelle/HOL theories is available via "isatool doc
   974 codegen".
   975 
   976 * Code generator: consts in 'consts_code' Isar commands are now
   977 referred to by usual term syntax (including optional type
   978 annotations).
   979 
   980 * Command 'no_translations' removes translation rules from theory
   981 syntax.
   982 
   983 * Overloaded definitions are now actually checked for acyclic
   984 dependencies.  The overloading scheme is slightly more general than
   985 that of Haskell98, although Isabelle does not demand an exact
   986 correspondence to type class and instance declarations.
   987 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   988 exotic versions of overloading -- at the discretion of the user!
   989 
   990 Polymorphic constants are represented via type arguments, i.e. the
   991 instantiation that matches an instance against the most general
   992 declaration given in the signature.  For example, with the declaration
   993 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   994 as c(nat).  Overloading is essentially simultaneous structural
   995 recursion over such type arguments.  Incomplete specification patterns
   996 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   997 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   998 Command 'print_theory' outputs the normalized system of recursive
   999 equations, see section "definitions".
  1000 
  1001 * Configuration options are maintained within the theory or proof
  1002 context (with name and type bool/int/string), providing a very simple
  1003 interface to a poor-man's version of general context data.  Tools may
  1004 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1005 these values using Config.get etc.  Users may change options via an
  1006 associated attribute of the same name.  This form of context
  1007 declaration works particularly well with commands 'declare' or
  1008 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1009 very easy to avoid global references, which would not observe Isar
  1010 toplevel undo/redo and fail to work with multithreading.
  1011 
  1012 Various global ML references of Pure and HOL have been turned into
  1013 configuration options:
  1014 
  1015   Unify.search_bound		unify_search_bound
  1016   Unify.trace_bound		unify_trace_bound
  1017   Unify.trace_simp		unify_trace_simp
  1018   Unify.trace_types		unify_trace_types
  1019   Simplifier.simp_depth_limit	simp_depth_limit
  1020   Blast.depth_limit		blast_depth_limit
  1021   DatatypeProp.dtK		datatype_distinctness_limit
  1022   fast_arith_neq_limit  	fast_arith_neq_limit
  1023   fast_arith_split_limit	fast_arith_split_limit
  1024 
  1025 * Named collections of theorems may be easily installed as context
  1026 data using the functor NamedThmsFun (see also
  1027 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1028 attributes; there is also a toplevel print command.  This facility is
  1029 just a common case of general context data, which is the preferred way
  1030 for anything more complex than just a list of facts in canonical
  1031 order.
  1032 
  1033 * Isar: command 'declaration' augments a local theory by generic
  1034 declaration functions written in ML.  This enables arbitrary content
  1035 being added to the context, depending on a morphism that tells the
  1036 difference of the original declaration context wrt. the application
  1037 context encountered later on.
  1038 
  1039 * Isar: proper interfaces for simplification procedures.  Command
  1040 'simproc_setup' declares named simprocs (with match patterns, and body
  1041 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1042 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1043 
  1044 * Isar: an extra pair of brackets around attribute declarations
  1045 abbreviates a theorem reference involving an internal dummy fact,
  1046 which will be ignored later --- only the effect of the attribute on
  1047 the background context will persist.  This form of in-place
  1048 declarations is particularly useful with commands like 'declare' and
  1049 'using', for example ``have A using [[simproc a]] by simp''.
  1050 
  1051 * Isar: method "assumption" (and implicit closing of subproofs) now
  1052 takes simple non-atomic goal assumptions into account: after applying
  1053 an assumption as a rule the resulting subgoals are solved by atomic
  1054 assumption steps.  This is particularly useful to finish 'obtain'
  1055 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1056 without referring to the original premise "!!x. P x ==> thesis" in the
  1057 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1058 more permissive.
  1059 
  1060 * Isar: implicit use of prems from the Isar proof context is
  1061 considered a legacy feature.  Common applications like ``have A .''
  1062 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1063 referencing facts explicitly here improves readability and
  1064 maintainability of proof texts.
  1065 
  1066 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1067 the obtained context from the course of reasoning!  For example:
  1068 
  1069   assume "EX x y. A x & B y"   -- "any previous fact"
  1070   then guess x and y by clarify
  1071 
  1072 This technique is potentially adventurous, depending on the facts and
  1073 proof tools being involved here.
  1074 
  1075 * Isar: known facts from the proof context may be specified as literal
  1076 propositions, using ASCII back-quote syntax.  This works wherever
  1077 named facts used to be allowed so far, in proof commands, proof
  1078 methods, attributes etc.  Literal facts are retrieved from the context
  1079 according to unification of type and term parameters.  For example,
  1080 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1081 theorems in the current context, then these are valid literal facts:
  1082 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1083 
  1084 There is also a proof method "fact" which does the same composition
  1085 for explicit goal states, e.g. the following proof texts coincide with
  1086 certain special cases of literal facts:
  1087 
  1088   have "A" by fact                 ==  note `A`
  1089   have "A ==> B" by fact           ==  note `A ==> B`
  1090   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1091   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1092 
  1093 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1094 outer syntax.  Thus symbolic identifiers may be used without
  1095 additional white space in declarations like this: ``assume *: A''.
  1096 
  1097 * Isar: 'print_facts' prints all local facts of the current context,
  1098 both named and unnamed ones.
  1099 
  1100 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1101 
  1102   def x == "t" and y == "u"
  1103 
  1104 * Isar: added command 'unfolding', which is structurally similar to
  1105 'using', but affects both the goal state and facts by unfolding given
  1106 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1107 'unfolded' attribute may be replaced by first-class proof text.
  1108 
  1109 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1110 and command 'unfolding' now all support object-level equalities
  1111 (potentially conditional).  The underlying notion of rewrite rule is
  1112 analogous to the 'rule_format' attribute, but *not* that of the
  1113 Simplifier (which is usually more generous).
  1114 
  1115 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1116 premises of a theorem by n. Useful in conjunction with drule.
  1117 
  1118 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1119 method expression within a sandbox consisting of the first N
  1120 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1121 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1122 simplifies all new goals that emerge from applying rule foo to the
  1123 originally first one.
  1124 
  1125 * Isar: schematic goals are no longer restricted to higher-order
  1126 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1127 expected.
  1128 
  1129 * Isar: the conclusion of a long theorem statement is now either
  1130 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1131 (essentially a disjunction of cases with local parameters and
  1132 assumptions).  The latter allows to express general elimination rules
  1133 adequately; in this notation common elimination rules look like this:
  1134 
  1135   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1136     assumes "EX x. P x"
  1137     obtains x where "P x"
  1138 
  1139   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1140     assumes "A & B"
  1141     obtains A and B
  1142 
  1143   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1144     assumes "A | B"
  1145     obtains
  1146       A
  1147     | B
  1148 
  1149 The subsequent classical rules even refer to the formal "thesis"
  1150 explicitly:
  1151 
  1152   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1153     obtains "~ thesis"
  1154 
  1155   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1156     obtains "thesis ==> something"
  1157 
  1158 The actual proof of an 'obtains' statement is analogous to that of the
  1159 Isar proof element 'obtain', only that there may be several cases.
  1160 Optional case names may be specified in parentheses; these will be
  1161 available both in the present proof and as annotations in the
  1162 resulting rule, for later use with the 'cases' method (cf. attribute
  1163 case_names).
  1164 
  1165 * Isar: the assumptions of a long theorem statement are available as
  1166 "assms" fact in the proof context.  This is more appropriate than the
  1167 (historical) "prems", which refers to all assumptions of the current
  1168 context, including those from the target locale, proof body etc.
  1169 
  1170 * Isar: 'print_statement' prints theorems from the current theory or
  1171 proof context in long statement form, according to the syntax of a
  1172 top-level lemma.
  1173 
  1174 * Isar: 'obtain' takes an optional case name for the local context
  1175 introduction rule (default "that").
  1176 
  1177 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1178 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1179 to occur.
  1180 
  1181 * Pure: syntax "CONST name" produces a fully internalized constant
  1182 according to the current context.  This is particularly useful for
  1183 syntax translations that should refer to internal constant
  1184 representations independently of name spaces.
  1185 
  1186 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1187 instead of "FOO ". This allows multiple binder declarations to coexist
  1188 in the same context.  INCOMPATIBILITY.
  1189 
  1190 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1191 primitive that also works in a locale context (both for constants and
  1192 fixed variables). Type declaration and internal syntactic representation
  1193 of given constants retrieved from the context. Likewise, the
  1194 'no_notation' command allows to remove given syntax annotations from the
  1195 current context.
  1196 
  1197 * Isar/locales: new derived specification elements 'axiomatization',
  1198 'definition', 'abbreviation', which support type-inference, admit
  1199 object-level specifications (equality, equivalence).  See also the
  1200 isar-ref manual.  Examples:
  1201 
  1202   axiomatization
  1203     eq  (infix "===" 50) where
  1204     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1205 
  1206   definition "f x y = x + y + 1"
  1207   definition g where "g x = f x x"
  1208 
  1209   abbreviation
  1210     neq  (infix "=!=" 50) where
  1211     "x =!= y == ~ (x === y)"
  1212 
  1213 These specifications may be also used in a locale context.  Then the
  1214 constants being introduced depend on certain fixed parameters, and the
  1215 constant name is qualified by the locale base name.  An internal
  1216 abbreviation takes care for convenient input and output, making the
  1217 parameters implicit and using the original short name.  See also
  1218 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1219 entities from a monomorphic theory.
  1220 
  1221 Presently, abbreviations are only available 'in' a target locale, but
  1222 not inherited by general import expressions.  Also note that
  1223 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1224 'translations' in common applications.  The "no_abbrevs" print mode
  1225 prevents folding of abbreviations in term output.
  1226 
  1227 Concrete syntax is attached to specified constants in internal form,
  1228 independently of name spaces.  The parse tree representation is
  1229 slightly different -- use 'notation' instead of raw 'syntax', and
  1230 'translations' with explicit "CONST" markup to accommodate this.
  1231 
  1232 * Pure/Isar: unified syntax for new-style specification mechanisms
  1233 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1234 full type inference and dummy patterns ("_").  For example:
  1235 
  1236   definition "K x _ = x"
  1237 
  1238   inductive conj for A B
  1239   where "A ==> B ==> conj A B"
  1240 
  1241 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1242 the current context.  Print mode "no_abbrevs" prevents inversion of
  1243 abbreviations on output.
  1244 
  1245 * Isar/locales: improved parameter handling: use of locales "var" and
  1246 "struct" no longer necessary; - parameter renamings are no longer
  1247 required to be injective.  For example, this allows to define
  1248 endomorphisms as locale endom = homom mult mult h.
  1249 
  1250 * Isar/locales: changed the way locales with predicates are defined.
  1251 Instead of accumulating the specification, the imported expression is
  1252 now an interpretation.  INCOMPATIBILITY: different normal form of
  1253 locale expressions.  In particular, in interpretations of locales with
  1254 predicates, goals repesenting already interpreted fragments are not
  1255 removed automatically.  Use methods `intro_locales' and
  1256 `unfold_locales'; see below.
  1257 
  1258 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1259 provide backward reasoning on locales predicates.  The methods are
  1260 aware of interpretations and discharge corresponding goals.
  1261 `intro_locales' is less aggressive then `unfold_locales' and does not
  1262 unfold predicates to assumptions.
  1263 
  1264 * Isar/locales: the order in which locale fragments are accumulated
  1265 has changed.  This enables to override declarations from fragments due
  1266 to interpretations -- for example, unwanted simp rules.
  1267 
  1268 * Isar/locales: interpretation in theories and proof contexts has been
  1269 extended.  One may now specify (and prove) equations, which are
  1270 unfolded in interpreted theorems.  This is useful for replacing
  1271 defined concepts (constants depending on locale parameters) by
  1272 concepts already existing in the target context.  Example:
  1273 
  1274   interpretation partial_order ["op <= :: [int, int] => bool"]
  1275     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1276 
  1277 Typically, the constant `partial_order.less' is created by a
  1278 definition specification element in the context of locale
  1279 partial_order.
  1280 
  1281 * Method "induct": improved internal context management to support
  1282 local fixes and defines on-the-fly. Thus explicit meta-level
  1283 connectives !!  and ==> are rarely required anymore in inductive goals
  1284 (using object-logic connectives for this purpose has been long
  1285 obsolete anyway). Common proof patterns are explained in
  1286 src/HOL/Induct/Common_Patterns.thy, see also
  1287 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1288 examples.
  1289 
  1290 * Method "induct": improved handling of simultaneous goals. Instead of
  1291 introducing object-level conjunction, the statement is now split into
  1292 several conclusions, while the corresponding symbolic cases are nested
  1293 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1294 see src/HOL/Induct/Common_Patterns.thy, for example.
  1295 
  1296 * Method "induct": mutual induction rules are now specified as a list
  1297 of rule sharing the same induction cases. HOL packages usually provide
  1298 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1299 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1300 mutual induction rules differently, i.e. like this:
  1301 
  1302   (induct rule: foo_bar.inducts)
  1303   (induct set: foo bar)
  1304   (induct pred: foo bar)
  1305   (induct type: foo bar)
  1306 
  1307 The ML function ProjectRule.projections turns old-style rules into the
  1308 new format.
  1309 
  1310 * Method "coinduct": dual of induction, see
  1311 src/HOL/Library/Coinductive_List.thy for various examples.
  1312 
  1313 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1314 considered a legacy feature.
  1315 
  1316 * Attribute "symmetric" produces result with standardized schematic
  1317 variables (index 0).  Potential INCOMPATIBILITY.
  1318 
  1319 * Simplifier: by default the simplifier trace only shows top level
  1320 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1321 default. Thus there is less danger of being flooded by the trace. The
  1322 trace indicates where parts have been suppressed.
  1323   
  1324 * Provers/classical: removed obsolete classical version of elim_format
  1325 attribute; classical elim/dest rules are now treated uniformly when
  1326 manipulating the claset.
  1327 
  1328 * Provers/classical: stricter checks to ensure that supplied intro,
  1329 dest and elim rules are well-formed; dest and elim rules must have at
  1330 least one premise.
  1331 
  1332 * Provers/classical: attributes dest/elim/intro take an optional
  1333 weight argument for the rule (just as the Pure versions).  Weights are
  1334 ignored by automated tools, but determine the search order of single
  1335 rule steps.
  1336 
  1337 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1338 where the body does not mention the bound variable.  Note that dummy
  1339 patterns implicitly depend on their context of bounds, which makes
  1340 "{_. _}" match any set comprehension as expected.  Potential
  1341 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1342 constant "_idtdummy" in the binding position.
  1343 
  1344 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1345 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1346 for example "A -> B" => "Pi A (%_. B)".
  1347 
  1348 * Pure: 'class_deps' command visualizes the subclass relation, using
  1349 the graph browser tool.
  1350 
  1351 * Pure: 'print_theory' now suppresses certain internal declarations by
  1352 default; use '!' option for full details.
  1353 
  1354 
  1355 *** HOL ***
  1356 
  1357 * Method "metis" proves goals by applying the Metis general-purpose
  1358 resolution prover (see also http://gilith.com/software/metis/).
  1359 Examples are in the directory MetisExamples.  WARNING: the
  1360 Isabelle/HOL-Metis integration does not yet work properly with
  1361 multi-threading.
  1362   
  1363 * Command 'sledgehammer' invokes external automatic theorem provers as
  1364 background processes.  It generates calls to the "metis" method if
  1365 successful. These can be pasted into the proof.  Users do not have to
  1366 wait for the automatic provers to return.  WARNING: does not really
  1367 work with multi-threading.
  1368 
  1369 * New "auto_quickcheck" feature tests outermost goal statements for
  1370 potential counter-examples.  Controlled by ML references
  1371 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1372 5000 milliseconds).  Fails silently if statements is outside of
  1373 executable fragment, or any other codgenerator problem occurs.
  1374 
  1375 * New constant "undefined" with axiom "undefined x = undefined".
  1376 
  1377 * Added class "HOL.eq", allowing for code generation with polymorphic
  1378 equality.
  1379 
  1380 * Some renaming of class constants due to canonical name prefixing in
  1381 the new 'class' package:
  1382 
  1383     HOL.abs ~> HOL.abs_class.abs
  1384     HOL.divide ~> HOL.divide_class.divide
  1385     0 ~> HOL.zero_class.zero
  1386     1 ~> HOL.one_class.one
  1387     op + ~> HOL.plus_class.plus
  1388     op - ~> HOL.minus_class.minus
  1389     uminus ~> HOL.minus_class.uminus
  1390     op * ~> HOL.times_class.times
  1391     op < ~> HOL.ord_class.less
  1392     op <= > HOL.ord_class.less_eq
  1393     Nat.power ~> Power.power_class.power
  1394     Nat.size ~> Nat.size_class.size
  1395     Numeral.number_of ~> Numeral.number_class.number_of
  1396     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1397     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1398     Orderings.min ~> Orderings.ord_class.min
  1399     Orderings.max ~> Orderings.ord_class.max
  1400     Divides.op div ~> Divides.div_class.div
  1401     Divides.op mod ~> Divides.div_class.mod
  1402     Divides.op dvd ~> Divides.div_class.dvd
  1403 
  1404 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1405 
  1406 a) User-defined constants using any of the names "plus", "minus",
  1407 "times", "less" or "less_eq". The standard syntax translations for
  1408 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1409 names.
  1410 
  1411 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1412 INCOMPATIBILITY: use more specific names.
  1413 
  1414 c) Permutative equations (e.g. "a + b = b + a")
  1415 Since the change of names also changes the order of terms, permutative
  1416 rewrite rules may get applied in a different order. Experience shows
  1417 that this is rarely the case (only two adaptions in the whole Isabelle
  1418 distribution).  INCOMPATIBILITY: rewrite proofs
  1419 
  1420 d) ML code directly refering to constant names
  1421 This in general only affects hand-written proof tactics, simprocs and
  1422 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1423 Consider using @{const_name} antiquotation.
  1424 
  1425 * New class "default" with associated constant "default".
  1426 
  1427 * Function "sgn" is now overloaded and available on int, real, complex
  1428 (and other numeric types), using class "sgn".  Two possible defs of
  1429 sgn are given as equational assumptions in the classes sgn_if and
  1430 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1431 INCOMPATIBILITY.
  1432 
  1433 * Locale "partial_order" now unified with class "order" (cf. theory
  1434 Orderings), added parameter "less".  INCOMPATIBILITY.
  1435 
  1436 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1437 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1438 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1439 
  1440 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1441 changed order of proof goals in instance proofs.
  1442 
  1443 * The transitivity reasoner for partial and linear orders is set up
  1444 for classes "order" and "linorder".  Instances of the reasoner are available
  1445 in all contexts importing or interpreting the corresponding locales.
  1446 Method "order" invokes the reasoner separately; the reasoner
  1447 is also integrated with the Simplifier as a solver.  Diagnostic
  1448 command 'print_orders' shows the available instances of the reasoner
  1449 in the current context.
  1450 
  1451 * Localized monotonicity predicate in theory "Orderings"; integrated
  1452 lemmas max_of_mono and min_of_mono with this predicate.
  1453 INCOMPATIBILITY.
  1454 
  1455 * Formulation of theorem "dense" changed slightly due to integration
  1456 with new class dense_linear_order.
  1457 
  1458 * Uniform lattice theory development in HOL.
  1459 
  1460     constants "meet" and "join" now named "inf" and "sup"
  1461     constant "Meet" now named "Inf"
  1462 
  1463     classes "meet_semilorder" and "join_semilorder" now named
  1464       "lower_semilattice" and "upper_semilattice"
  1465     class "lorder" now named "lattice"
  1466     class "comp_lat" now named "complete_lattice"
  1467 
  1468     Instantiation of lattice classes allows explicit definitions
  1469     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1470 
  1471   INCOMPATIBILITY.  Theorem renames:
  1472 
  1473     meet_left_le            ~> inf_le1
  1474     meet_right_le           ~> inf_le2
  1475     join_left_le            ~> sup_ge1
  1476     join_right_le           ~> sup_ge2
  1477     meet_join_le            ~> inf_sup_ord
  1478     le_meetI                ~> le_infI
  1479     join_leI                ~> le_supI
  1480     le_meet                 ~> le_inf_iff
  1481     le_join                 ~> ge_sup_conv
  1482     meet_idempotent         ~> inf_idem
  1483     join_idempotent         ~> sup_idem
  1484     meet_comm               ~> inf_commute
  1485     join_comm               ~> sup_commute
  1486     meet_leI1               ~> le_infI1
  1487     meet_leI2               ~> le_infI2
  1488     le_joinI1               ~> le_supI1
  1489     le_joinI2               ~> le_supI2
  1490     meet_assoc              ~> inf_assoc
  1491     join_assoc              ~> sup_assoc
  1492     meet_left_comm          ~> inf_left_commute
  1493     meet_left_idempotent    ~> inf_left_idem
  1494     join_left_comm          ~> sup_left_commute
  1495     join_left_idempotent    ~> sup_left_idem
  1496     meet_aci                ~> inf_aci
  1497     join_aci                ~> sup_aci
  1498     le_def_meet             ~> le_iff_inf
  1499     le_def_join             ~> le_iff_sup
  1500     join_absorp2            ~> sup_absorb2
  1501     join_absorp1            ~> sup_absorb1
  1502     meet_absorp1            ~> inf_absorb1
  1503     meet_absorp2            ~> inf_absorb2
  1504     meet_join_absorp        ~> inf_sup_absorb
  1505     join_meet_absorp        ~> sup_inf_absorb
  1506     distrib_join_le         ~> distrib_sup_le
  1507     distrib_meet_le         ~> distrib_inf_le
  1508 
  1509     add_meet_distrib_left   ~> add_inf_distrib_left
  1510     add_join_distrib_left   ~> add_sup_distrib_left
  1511     is_join_neg_meet        ~> is_join_neg_inf
  1512     is_meet_neg_join        ~> is_meet_neg_sup
  1513     add_meet_distrib_right  ~> add_inf_distrib_right
  1514     add_join_distrib_right  ~> add_sup_distrib_right
  1515     add_meet_join_distribs  ~> add_sup_inf_distribs
  1516     join_eq_neg_meet        ~> sup_eq_neg_inf
  1517     meet_eq_neg_join        ~> inf_eq_neg_sup
  1518     add_eq_meet_join        ~> add_eq_inf_sup
  1519     meet_0_imp_0            ~> inf_0_imp_0
  1520     join_0_imp_0            ~> sup_0_imp_0
  1521     meet_0_eq_0             ~> inf_0_eq_0
  1522     join_0_eq_0             ~> sup_0_eq_0
  1523     neg_meet_eq_join        ~> neg_inf_eq_sup
  1524     neg_join_eq_meet        ~> neg_sup_eq_inf
  1525     join_eq_if              ~> sup_eq_if
  1526 
  1527     mono_meet               ~> mono_inf
  1528     mono_join               ~> mono_sup
  1529     meet_bool_eq            ~> inf_bool_eq
  1530     join_bool_eq            ~> sup_bool_eq
  1531     meet_fun_eq             ~> inf_fun_eq
  1532     join_fun_eq             ~> sup_fun_eq
  1533     meet_set_eq             ~> inf_set_eq
  1534     join_set_eq             ~> sup_set_eq
  1535     meet1_iff               ~> inf1_iff
  1536     meet2_iff               ~> inf2_iff
  1537     meet1I                  ~> inf1I
  1538     meet2I                  ~> inf2I
  1539     meet1D1                 ~> inf1D1
  1540     meet2D1                 ~> inf2D1
  1541     meet1D2                 ~> inf1D2
  1542     meet2D2                 ~> inf2D2
  1543     meet1E                  ~> inf1E
  1544     meet2E                  ~> inf2E
  1545     join1_iff               ~> sup1_iff
  1546     join2_iff               ~> sup2_iff
  1547     join1I1                 ~> sup1I1
  1548     join2I1                 ~> sup2I1
  1549     join1I1                 ~> sup1I1
  1550     join2I2                 ~> sup1I2
  1551     join1CI                 ~> sup1CI
  1552     join2CI                 ~> sup2CI
  1553     join1E                  ~> sup1E
  1554     join2E                  ~> sup2E
  1555 
  1556     is_meet_Meet            ~> is_meet_Inf
  1557     Meet_bool_def           ~> Inf_bool_def
  1558     Meet_fun_def            ~> Inf_fun_def
  1559     Meet_greatest           ~> Inf_greatest
  1560     Meet_lower              ~> Inf_lower
  1561     Meet_set_def            ~> Inf_set_def
  1562 
  1563     Sup_def                 ~> Sup_Inf
  1564     Sup_bool_eq             ~> Sup_bool_def
  1565     Sup_fun_eq              ~> Sup_fun_def
  1566     Sup_set_eq              ~> Sup_set_def
  1567 
  1568     listsp_meetI            ~> listsp_infI
  1569     listsp_meet_eq          ~> listsp_inf_eq
  1570 
  1571     meet_min                ~> inf_min
  1572     join_max                ~> sup_max
  1573 
  1574 * Added syntactic class "size"; overloaded constant "size" now has
  1575 type "'a::size ==> bool"
  1576 
  1577 * Internal reorganisation of `size' of datatypes: size theorems
  1578 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1579 simplification rules by default!); theorems "prod.size" now named
  1580 "*.size".
  1581 
  1582 * Class "div" now inherits from class "times" rather than "type".
  1583 INCOMPATIBILITY.
  1584 
  1585 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1586 Linorder etc.  have disappeared; operations defined in terms of
  1587 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1588 
  1589 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1590 
  1591 * HOL-Word: New extensive library and type for generic, fixed size
  1592 machine words, with arithemtic, bit-wise, shifting and rotating
  1593 operations, reflection into int, nat, and bool lists, automation for
  1594 linear arithmetic (by automatic reflection into nat or int), including
  1595 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1596 arithmetic type classes, supporting automatic simplification of
  1597 numerals on all operations.
  1598 
  1599 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1600 
  1601 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1602 
  1603 * Code generator library theories:
  1604   - Code_Integer represents HOL integers by big integer literals in target
  1605     languages.
  1606   - Code_Char represents HOL characters by character literals in target
  1607     languages.
  1608   - Code_Char_chr like Code_Char, but also offers treatment of character
  1609     codes; includes Code_Integer.
  1610   - Executable_Set allows to generate code for finite sets using lists.
  1611   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1612     denominator).
  1613   - Executable_Real implements a subset of real numbers, namly those
  1614     representable by rational numbers.
  1615   - Efficient_Nat implements natural numbers by integers, which in general will
  1616     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1617     includes Code_Integer.
  1618   - Code_Index provides an additional datatype index which is mapped to
  1619     target-language built-in integers.
  1620   - Code_Message provides an additional datatype message_string which is isomorphic to
  1621     strings; messages are mapped to target-language strings.
  1622 
  1623 * New package for inductive predicates
  1624 
  1625   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1626 
  1627     inductive
  1628       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1629       for z_1 :: U_1 and ... and z_n :: U_m
  1630     where
  1631       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1632     | ...
  1633 
  1634   with full support for type-inference, rather than
  1635 
  1636     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1637 
  1638     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1639     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1640 
  1641     inductive "s z_1 ... z_m"
  1642     intros
  1643       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1644       ...
  1645 
  1646   For backward compatibility, there is a wrapper allowing inductive
  1647   sets to be defined with the new package via
  1648 
  1649     inductive_set
  1650       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1651       for z_1 :: U_1 and ... and z_n :: U_m
  1652     where
  1653       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1654     | ...
  1655 
  1656   or
  1657 
  1658     inductive_set
  1659       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1660       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1661       for z_1 :: U_1 and ... and z_n :: U_m
  1662     where
  1663       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1664     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1665     | ...
  1666 
  1667   if the additional syntax "p ..." is required.
  1668 
  1669   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1670   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1671 
  1672   INCOMPATIBILITIES:
  1673 
  1674   - Since declaration and definition of inductive sets or predicates
  1675     is no longer separated, abbreviations involving the newly
  1676     introduced sets or predicates must be specified together with the
  1677     introduction rules after the 'where' keyword (see above), rather
  1678     than before the actual inductive definition.
  1679 
  1680   - The variables in induction and elimination rules are now
  1681     quantified in the order of their occurrence in the introduction
  1682     rules, rather than in alphabetical order. Since this may break
  1683     some proofs, these proofs either have to be repaired, e.g. by
  1684     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1685     statements of the form
  1686 
  1687       case (rule_i a_i_1 ... a_i_{k_i})
  1688 
  1689     or the old order of quantification has to be restored by explicitly adding
  1690     meta-level quantifiers in the introduction rules, i.e.
  1691 
  1692       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  1693 
  1694   - The format of the elimination rules is now
  1695 
  1696       p z_1 ... z_m x_1 ... x_n ==>
  1697         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1698         ==> ... ==> P
  1699 
  1700     for predicates and
  1701 
  1702       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1703         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1704         ==> ... ==> P
  1705 
  1706     for sets rather than
  1707 
  1708       x : s z_1 ... z_m ==>
  1709         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1710         ==> ... ==> P
  1711 
  1712     This may require terms in goals to be expanded to n-tuples
  1713     (e.g. using case_tac or simplification with the split_paired_all
  1714     rule) before the above elimination rule is applicable.
  1715 
  1716   - The elimination or case analysis rules for (mutually) inductive
  1717     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1718     list of rules "p_1_..._p_k.elims" is no longer available.
  1719 
  1720 * New package "function"/"fun" for general recursive functions,
  1721 supporting mutual and nested recursion, definitions in local contexts,
  1722 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1723 for small examples, and the separate tutorial on the function
  1724 package. The old recdef "package" is still available as before, but
  1725 users are encouraged to use the new package.
  1726 
  1727 * Method "lexicographic_order" automatically synthesizes termination
  1728 relations as lexicographic combinations of size measures. 
  1729 
  1730 * Case-expressions allow arbitrary constructor-patterns (including
  1731 "_") and take their order into account, like in functional
  1732 programming.  Internally, this is translated into nested
  1733 case-expressions; missing cases are added and mapped to the predefined
  1734 constant "undefined". In complicated cases printing may no longer show
  1735 the original input but the internal form. Lambda-abstractions allow
  1736 the same form of pattern matching: "% pat1 => e1 | ..." is an
  1737 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  1738 variable.
  1739 
  1740 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  1741 is an abbreviation for "of_nat :: nat => int". The simplification
  1742 rules for "of_nat" have been changed to work like "int" did
  1743 previously.  Potential INCOMPATIBILITY:
  1744   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  1745   - of_nat_diff and of_nat_mult are no longer default simp rules
  1746 
  1747 * Method "algebra" solves polynomial equations over (semi)rings using
  1748 Groebner bases. The (semi)ring structure is defined by locales and the
  1749 tool setup depends on that generic context. Installing the method for
  1750 a specific type involves instantiating the locale and possibly adding
  1751 declarations for computation on the coefficients.  The method is
  1752 already instantiated for natural numbers and for the axiomatic class
  1753 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  1754 CALCULEMUS 2007 for the general principles underlying this
  1755 architecture of context-aware proof-tools.
  1756 
  1757 * Method "ferrack" implements quantifier elimination over
  1758 special-purpose dense linear orders using locales (analogous to
  1759 "algebra"). The method is already installed for class
  1760 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  1761 rat, etc.
  1762 
  1763 * Former constant "List.op @" now named "List.append".  Use ML
  1764 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  1765 circumvent possible incompatibilities when working on ML level.
  1766 
  1767 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1768 
  1769 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1770 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1771 
  1772 * New syntax for Haskell-like list comprehension (input only), eg.
  1773 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1774 
  1775 * The special syntax for function "filter" has changed from [x :
  1776 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1777 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1778 
  1779 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1780 defined on nat only, as an abbreviation for [a..<Suc b]
  1781 INCOMPATIBILITY.
  1782 
  1783 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1784 
  1785 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1786 
  1787 * New lemma collection field_simps (an extension of ring_simps) for
  1788 manipulating (in)equations involving division. Multiplies with all
  1789 denominators that can be proved to be non-zero (in equations) or
  1790 positive/negative (in inequations).
  1791 
  1792 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1793 have been improved and renamed to ring_simps, group_simps and
  1794 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1795 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1796 
  1797 * Theory Library/Commutative_Ring: switched from recdef to function
  1798 package; constants add, mul, pow now curried.  Infix syntax for
  1799 algebraic operations.
  1800 
  1801 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1802 INCOMPATIBILITY.
  1803 
  1804 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1805 INCOMPATIBILITY.
  1806 
  1807 * HOL/records: generalised field-update to take a function on the
  1808 field rather than the new value: r(|A := x|) is translated to A_update
  1809 (K x) r The K-combinator that is internally used is called K_record.
  1810 INCOMPATIBILITY: Usage of the plain update functions has to be
  1811 adapted.
  1812  
  1813 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1814 * x = 0, which are required for a semiring.  Richer structures do not
  1815 inherit from semiring_0 anymore, because this property is a theorem
  1816 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1817 there is more to prove, but this is mostly trivial.
  1818 
  1819 * Class "recpower" is generalized to arbitrary monoids, not just
  1820 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1821 commutativity or semiring properties additionally.
  1822 
  1823 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1824 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1825 better use 'abbreviation'.
  1826 
  1827 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1828 
  1829 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1830 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1831 significant changes for setting up numeral syntax for types:
  1832   - New constants Numeral.pred and Numeral.succ instead
  1833       of former Numeral.bin_pred and Numeral.bin_succ.
  1834   - Use integer operations instead of bin_add, bin_mult and so on.
  1835   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1836   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1837 
  1838 See src/HOL/Integ/IntArith.thy for an example setup.
  1839 
  1840 * Command 'normal_form' computes the normal form of a term that may
  1841 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1842 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1843 heavy-duty computations because the functions are compiled to ML
  1844 first.  Correspondingly, a method "normalization" is provided.  See
  1845 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1846 
  1847 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1848 25 like -->); output depends on the "iff" print_mode, the default is
  1849 "A = B" (with priority 50).
  1850 
  1851 * Relations less (<) and less_eq (<=) are also available on type bool.
  1852 Modified syntax to disallow nesting without explicit parentheses,
  1853 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1854 INCOMPATIBILITY.
  1855 
  1856 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1857 
  1858 * Relation composition operator "op O" now has precedence 75 and binds
  1859 stronger than union and intersection. INCOMPATIBILITY.
  1860 
  1861 * The old set interval syntax "{m..n(}" (and relatives) has been
  1862 removed.  Use "{m..<n}" (and relatives) instead.
  1863 
  1864 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1865 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1866 ``declare [[simproc del: neq]]''.
  1867 
  1868 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1869 True/False.
  1870 
  1871 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1872 
  1873 * Theorem setsum_mult renamed to setsum_right_distrib.
  1874 
  1875 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1876 ``rule'' method.
  1877 
  1878 * Reimplemented methods "sat" and "satx", with several improvements:
  1879 goals no longer need to be stated as "<prems> ==> False", equivalences
  1880 (i.e. "=" on type bool) are handled, variable names of the form
  1881 "lit_<n>" are no longer reserved, significant speedup.
  1882 
  1883 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1884 zChaff is still supported as well.
  1885 
  1886 * 'inductive' and 'datatype': provide projections of mutual rules,
  1887 bundled as foo_bar.inducts;
  1888 
  1889 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1890 Library.
  1891 
  1892 * Library: moved theory Accessible_Part to main HOL.
  1893 
  1894 * Library: added theory Coinductive_List of potentially infinite lists
  1895 as greatest fixed-point.
  1896 
  1897 * Library: added theory AssocList which implements (finite) maps as
  1898 association lists.
  1899 
  1900 * Method "evaluation" solves goals (i.e. a boolean expression)
  1901 efficiently by compiling it to ML.  The goal is "proved" (via an
  1902 oracle) if it evaluates to True.
  1903 
  1904 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1905 also when invoked by the simplifier.  This results in the Simplifier
  1906 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1907 Configuration option fast_arith_split_limit=0 recovers the old
  1908 behavior.
  1909 
  1910 * Support for hex (0x20) and binary (0b1001) numerals.
  1911 
  1912 * New method: reify eqs (t), where eqs are equations for an
  1913 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1914 parameter, computes a term s::'b and a list xs::'a list and proves the
  1915 theorem I xs s = t. This is also known as reification or quoting. The
  1916 resulting theorem is applied to the subgoal to substitute t with I xs
  1917 s.  If t is omitted, the subgoal itself is reified.
  1918 
  1919 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1920 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1921 where f is supposed to be a computable function (in the sense of code
  1922 generattion). The method uses reify to compute s and xs as above then
  1923 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1924 r and finally gets the theorem t = r, which is again applied to the
  1925 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1926 
  1927 * Reflection: Automatic reification now handels binding, an example is
  1928 available in src/HOL/ex/ReflectionEx.thy
  1929 
  1930 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  1931 command 'statespace' that is similar to 'record', but introduces an
  1932 abstract specification based on the locale infrastructure instead of
  1933 HOL types.  This leads to extra flexibility in composing state spaces,
  1934 in particular multiple inheritance and renaming of components.
  1935 
  1936 
  1937 *** HOL-Complex ***
  1938 
  1939 * Hyperreal: Functions root and sqrt are now defined on negative real
  1940 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1941 Nonnegativity side conditions have been removed from many lemmas, so
  1942 that more subgoals may now be solved by simplification; potential
  1943 INCOMPATIBILITY.
  1944 
  1945 * Real: new type classes formalize real normed vector spaces and
  1946 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1947 and norm :: 'a => real.
  1948 
  1949 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1950 reals into other types. The overloaded constant Reals :: 'a set is now
  1951 defined as range of_real; potential INCOMPATIBILITY.
  1952 
  1953 * Real: proper support for ML code generation, including 'quickcheck'.
  1954 Reals are implemented as arbitrary precision rationals.
  1955 
  1956 * Hyperreal: Several constants that previously worked only for the
  1957 reals have been generalized, so they now work over arbitrary vector
  1958 spaces. Type annotations may need to be added in some cases; potential
  1959 INCOMPATIBILITY.
  1960 
  1961   Infinitesimal  :: ('a::real_normed_vector) star set
  1962   HFinite        :: ('a::real_normed_vector) star set
  1963   HInfinite      :: ('a::real_normed_vector) star set
  1964   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1965   monad          :: ('a::real_normed_vector) star => 'a star set
  1966   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1967   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1968   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1969   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1970   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1971   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1972   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1973   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1974   sgn            :: 'a::real_normed_vector => 'a
  1975   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1976 
  1977 * Complex: Some complex-specific constants are now abbreviations for
  1978 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1979 hnorm.  Other constants have been entirely removed in favor of the
  1980 polymorphic versions (INCOMPATIBILITY):
  1981 
  1982   approx        <-- capprox
  1983   HFinite       <-- CFinite
  1984   HInfinite     <-- CInfinite
  1985   Infinitesimal <-- CInfinitesimal
  1986   monad         <-- cmonad
  1987   galaxy        <-- cgalaxy
  1988   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1989   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1990   (ns)deriv     <-- (ns)cderiv
  1991 
  1992 
  1993 *** HOL-Algebra ***
  1994 
  1995 * Formalisation of ideals and the quotient construction over rings.
  1996 
  1997 * Order and lattice theory no longer based on records.
  1998 INCOMPATIBILITY.
  1999 
  2000 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2001 greatest_closed.  INCOMPATIBILITY.
  2002 
  2003 * Method algebra is now set up via an attribute.  For examples see
  2004 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2005 of algebraic structures.
  2006 
  2007 * Renamed theory CRing to Ring.
  2008 
  2009 
  2010 *** HOL-Nominal ***
  2011 
  2012 * Substantial, yet incomplete support for nominal datatypes (binding
  2013 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2014 src/HOL/Nominal/Examples.  Prospective users should consult
  2015 http://isabelle.in.tum.de/nominal/
  2016 
  2017 
  2018 *** ML ***
  2019 
  2020 * ML basics: just one true type int, which coincides with IntInf.int
  2021 (even on SML/NJ).
  2022 
  2023 * ML within Isar: antiquotations allow to embed statically-checked
  2024 formal entities in the source, referring to the context available at
  2025 compile-time.  For example:
  2026 
  2027 ML {* @{sort "{zero,one}"} *}
  2028 ML {* @{typ "'a => 'b"} *}
  2029 ML {* @{term "%x. x"} *}
  2030 ML {* @{prop "x == y"} *}
  2031 ML {* @{ctyp "'a => 'b"} *}
  2032 ML {* @{cterm "%x. x"} *}
  2033 ML {* @{cprop "x == y"} *}
  2034 ML {* @{thm asm_rl} *}
  2035 ML {* @{thms asm_rl} *}
  2036 ML {* @{type_name c} *}
  2037 ML {* @{type_syntax c} *}
  2038 ML {* @{const_name c} *}
  2039 ML {* @{const_syntax c} *}
  2040 ML {* @{context} *}
  2041 ML {* @{theory} *}
  2042 ML {* @{theory Pure} *}
  2043 ML {* @{theory_ref} *}
  2044 ML {* @{theory_ref Pure} *}
  2045 ML {* @{simpset} *}
  2046 ML {* @{claset} *}
  2047 ML {* @{clasimpset} *}
  2048 
  2049 The same works for sources being ``used'' within an Isar context.
  2050 
  2051 * ML in Isar: improved error reporting; extra verbosity with
  2052 ML_Context.trace enabled.
  2053 
  2054 * Pure/General/table.ML: the join operations now works via exceptions
  2055 DUP/SAME instead of type option. This is simpler in simple cases, and
  2056 admits slightly more efficient complex applications.
  2057 
  2058 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2059 use Context.generic instead of just theory.
  2060 
  2061 * Pure: datatype Context.generic joins theory/Proof.context and
  2062 provides some facilities for code that works in either kind of
  2063 context, notably GenericDataFun for uniform theory and proof data.
  2064 
  2065 * Pure: simplified internal attribute type, which is now always
  2066 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2067 local (Proof.context) attributes have been discontinued, while
  2068 minimizing code duplication. Thm.rule_attribute and
  2069 Thm.declaration_attribute build canonical attributes; see also structure
  2070 Context for further operations on Context.generic, notably
  2071 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2072 declarations and definitions.
  2073 
  2074 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2075 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2076 init only required for impure data. INCOMPATIBILITY: empty really need
  2077 to be empty (no dependencies on theory content!)
  2078 
  2079 * Pure/kernel: consts certification ignores sort constraints given in
  2080 signature declarations. (This information is not relevant to the
  2081 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2082 potential INCOMPATIBILITY.
  2083 
  2084 * Pure: axiomatic type classes are now purely definitional, with
  2085 explicit proofs of class axioms and super class relations performed
  2086 internally. See Pure/axclass.ML for the main internal interfaces --
  2087 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2088 AxClass.axiomatize_class/classrel/arity supersede
  2089 Sign.add_classes/classrel/arities.
  2090 
  2091 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2092 global/local versions on theory vs. Proof.context have been
  2093 discontinued; Attrib.syntax and Method.syntax have been adapted
  2094 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2095 attributes, methods, etc.
  2096 
  2097 * Pure: several functions of signature "... -> theory -> theory * ..."
  2098 have been reoriented to "... -> theory -> ... * theory" in order to
  2099 allow natural usage in combination with the ||>, ||>>, |-> and
  2100 fold_map combinators.
  2101 
  2102 * Pure: official theorem names (closed derivations) and additional
  2103 comments (tags) are now strictly separate.  Name hints -- which are
  2104 maintained as tags -- may be attached any time without affecting the
  2105 derivation.
  2106 
  2107 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2108 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2109 achieve the old behaviour.
  2110 
  2111 * Pure: the "Goal" constant is now called "prop", supporting a
  2112 slightly more general idea of ``protecting'' meta-level rule
  2113 statements.
  2114 
  2115 * Pure: Logic.(un)varify only works in a global context, which is now
  2116 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2117 Logic.legacy_(un)varify as temporary workaround.
  2118 
  2119 * Pure: structure Name provides scalable operations for generating
  2120 internal variable names, notably Name.variants etc.  This replaces
  2121 some popular functions from term.ML:
  2122 
  2123   Term.variant		->  Name.variant
  2124   Term.variantlist	->  Name.variant_list
  2125   Term.invent_names	->  Name.invent_list
  2126 
  2127 Note that low-level renaming rarely occurs in new code -- operations
  2128 from structure Variable are used instead (see below).
  2129 
  2130 * Pure: structure Variable provides fundamental operations for proper
  2131 treatment of fixed/schematic variables in a context.  For example,
  2132 Variable.import introduces fixes for schematics of given facts and
  2133 Variable.export reverses the effect (up to renaming) -- this replaces
  2134 various freeze_thaw operations.
  2135 
  2136 * Pure: structure Goal provides simple interfaces for
  2137 init/conclude/finish and tactical prove operations (replacing former
  2138 Tactic.prove).  Goal.prove is the canonical way to prove results
  2139 within a given context; Goal.prove_global is a degraded version for
  2140 theory level goals, including a global Drule.standard.  Note that
  2141 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2142 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2143 in a locale context).
  2144 
  2145 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2146 and type checking (Syntax.check_term etc.), with common combinations
  2147 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2148 which are considered legacy and await removal.
  2149 
  2150 * Pure/Syntax: generic interfaces for type unchecking
  2151 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2152 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2153 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2154 available for convenience, but refer to the very same operations using
  2155 a mere theory instead of a full context.
  2156 
  2157 * Isar: simplified treatment of user-level errors, using exception
  2158 ERROR of string uniformly.  Function error now merely raises ERROR,
  2159 without any side effect on output channels.  The Isar toplevel takes
  2160 care of proper display of ERROR exceptions.  ML code may use plain
  2161 handle/can/try; cat_error may be used to concatenate errors like this:
  2162 
  2163   ... handle ERROR msg => cat_error msg "..."
  2164 
  2165 Toplevel ML code (run directly or through the Isar toplevel) may be
  2166 embedded into the Isar toplevel with exception display/debug like
  2167 this:
  2168 
  2169   Isar.toplevel (fn () => ...)
  2170 
  2171 INCOMPATIBILITY, removed special transform_error facilities, removed
  2172 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2173 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2174 -- use plain ERROR instead.
  2175 
  2176 * Isar: theory setup now has type (theory -> theory), instead of a
  2177 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2178 
  2179 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2180 ProofContext.debug/verbose flags.
  2181 
  2182 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2183 theory before entering a proof state.  Transactions now always see a
  2184 quasi-functional intermediate checkpoint, both in interactive and
  2185 batch mode.
  2186 
  2187 * Isar: simplified interfaces for outer syntax.  Renamed
  2188 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2189 OuterSyntax.add_parsers -- this functionality is now included in
  2190 OuterSyntax.command etc.  INCOMPATIBILITY.
  2191 
  2192 * Simplifier: the simpset of a running simplification process now
  2193 contains a proof context (cf. Simplifier.the_context), which is the
  2194 very context that the initial simpset has been retrieved from (by
  2195 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2196 (solver, looper etc.) may depend on arbitrary proof data.
  2197 
  2198 * Simplifier.inherit_context inherits the proof context (plus the
  2199 local bounds) of the current simplification process; any simproc
  2200 etc. that calls the Simplifier recursively should do this!  Removed
  2201 former Simplifier.inherit_bounds, which is already included here --
  2202 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2203 specify an explicit context using Simplifier.context/theory_context.
  2204 
  2205 * Simplifier/Classical Reasoner: more abstract interfaces
  2206 change_simpset/claset for modifying the simpset/claset reference of a
  2207 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2208 INCOMPATIBILITY.
  2209 
  2210 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2211 "Trueprop" etc.
  2212 
  2213 
  2214 *** System ***
  2215 
  2216 * settings: the default heap location within ISABELLE_HOME_USER now
  2217 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2218 Isabelle installations.
  2219 
  2220 * isabelle-process: option -S (secure mode) disables some critical
  2221 operations, notably runtime compilation and evaluation of ML source
  2222 code.
  2223 
  2224 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2225 
  2226 * Support for parallel execution, using native multicore support of
  2227 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2228 independent theories, according to the given theory header
  2229 specifications. The maximum number of worker threads is specified via
  2230 usedir option -M or the "max-threads" setting in Proof General. A
  2231 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2232 to 6 on a 8-core machine.  User-code needs to observe certain
  2233 guidelines for thread-safe programming, see appendix A in the Isar
  2234 Implementation manual.
  2235 
  2236 
  2237 
  2238 New in Isabelle2005 (October 2005)
  2239 ----------------------------------
  2240 
  2241 *** General ***
  2242 
  2243 * Theory headers: the new header syntax for Isar theories is
  2244 
  2245   theory <name>
  2246   imports <theory1> ... <theoryN>
  2247   uses <file1> ... <fileM>
  2248   begin
  2249 
  2250 where the 'uses' part is optional.  The previous syntax
  2251 
  2252   theory <name> = <theory1> + ... + <theoryN>:
  2253 
  2254 will disappear in the next release.  Use isatool fixheaders to convert
  2255 existing theory files.  Note that there is no change in ancient
  2256 non-Isar theories now, but these will disappear soon.
  2257 
  2258 * Theory loader: parent theories can now also be referred to via
  2259 relative and absolute paths.
  2260 
  2261 * Command 'find_theorems' searches for a list of criteria instead of a
  2262 list of constants. Known criteria are: intro, elim, dest, name:string,
  2263 simp:term, and any term. Criteria can be preceded by '-' to select
  2264 theorems that do not match. Intro, elim, dest select theorems that
  2265 match the current goal, name:s selects theorems whose fully qualified
  2266 name contain s, and simp:term selects all simplification rules whose
  2267 lhs match term.  Any other term is interpreted as pattern and selects
  2268 all theorems matching the pattern. Available in ProofGeneral under
  2269 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2270 
  2271   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2272 
  2273 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2274 matching the current goal as introduction rule and not having "HOL."
  2275 in their name (i.e. not being defined in theory HOL).
  2276 
  2277 * Command 'thms_containing' has been discontinued in favour of
  2278 'find_theorems'; INCOMPATIBILITY.
  2279 
  2280 * Communication with Proof General is now 8bit clean, which means that
  2281 Unicode text in UTF-8 encoding may be used within theory texts (both
  2282 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2283 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2284 
  2285   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2286   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2287 
  2288 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2289 Classical Reasoner.  Typical big applications run around 2 times
  2290 faster.
  2291 
  2292 
  2293 *** Document preparation ***
  2294 
  2295 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2296 of raw sources.  Only those symbols that do not require additional
  2297 LaTeX packages (depending on comments in isabellesym.sty) are
  2298 displayed properly, everything else is left verbatim.  isatool display
  2299 and isatool print are used as front ends (these are subject to the
  2300 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2301 
  2302 * Command tags control specific markup of certain regions of text,
  2303 notably folding and hiding.  Predefined tags include "theory" (for
  2304 theory begin and end), "proof" for proof commands, and "ML" for
  2305 commands involving ML code; the additional tags "visible" and
  2306 "invisible" are unused by default.  Users may give explicit tag
  2307 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2308 interpretation of tags is determined by the LaTeX job during document
  2309 preparation: see option -V of isatool usedir, or options -n and -t of
  2310 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2311 \isadroptag.
  2312 
  2313 Several document versions may be produced at the same time via isatool
  2314 usedir (the generated index.html will link all of them).  Typical
  2315 specifications include ''-V document=theory,proof,ML'' to present
  2316 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2317 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2318 these parts without any formal replacement text.  The Isabelle site
  2319 default settings produce ''document'' and ''outline'' versions as
  2320 specified above.
  2321 
  2322 * Several new antiquotations:
  2323 
  2324   @{term_type term} prints a term with its type annotated;
  2325 
  2326   @{typeof term} prints the type of a term;
  2327 
  2328   @{const const} is the same as @{term const}, but checks that the
  2329   argument is a known logical constant;
  2330 
  2331   @{term_style style term} and @{thm_style style thm} print a term or
  2332   theorem applying a "style" to it
  2333 
  2334   @{ML text}
  2335 
  2336 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2337 definitions, equations, inequations etc., 'concl' printing only the
  2338 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2339 to print the specified premise.  TermStyle.add_style provides an ML
  2340 interface for introducing further styles.  See also the "LaTeX Sugar"
  2341 document practical applications.  The ML antiquotation prints
  2342 type-checked ML expressions verbatim.
  2343 
  2344 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2345 and 'text' support optional locale specification '(in loc)', which
  2346 specifies the default context for interpreting antiquotations.  For
  2347 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2348 
  2349 * Option 'locale=NAME' of antiquotations specifies an alternative
  2350 context interpreting the subsequent argument.  For example: @{thm
  2351 [locale=lattice] inf_assoc}.
  2352 
  2353 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2354 a proof context.
  2355 
  2356 * Proper output of antiquotations for theory commands involving a
  2357 proof context (such as 'locale' or 'theorem (in loc) ...').
  2358 
  2359 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2360 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2361 
  2362 * isatool usedir: new option -C (default true) controls whether option
  2363 -D should include a copy of the original document directory; -C false
  2364 prevents unwanted effects such as copying of administrative CVS data.
  2365 
  2366 
  2367 *** Pure ***
  2368 
  2369 * Considerably improved version of 'constdefs' command.  Now performs
  2370 automatic type-inference of declared constants; additional support for
  2371 local structure declarations (cf. locales and HOL records), see also
  2372 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2373 sequential dependencies of definitions within a single 'constdefs'
  2374 section; moreover, the declared name needs to be an identifier.  If
  2375 all fails, consider to fall back on 'consts' and 'defs' separately.
  2376 
  2377 * Improved indexed syntax and implicit structures.  First of all,
  2378 indexed syntax provides a notational device for subscripted
  2379 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2380 expressions.  Secondly, in a local context with structure
  2381 declarations, number indexes \<^sub>n or the empty index (default
  2382 number 1) refer to a certain fixed variable implicitly; option
  2383 show_structs controls printing of implicit structures.  Typical
  2384 applications of these concepts involve record types and locales.
  2385 
  2386 * New command 'no_syntax' removes grammar declarations (and
  2387 translations) resulting from the given syntax specification, which is
  2388 interpreted in the same manner as for the 'syntax' command.
  2389 
  2390 * 'Advanced' translation functions (parse_translation etc.) may depend
  2391 on the signature of the theory context being presently used for
  2392 parsing/printing, see also isar-ref manual.
  2393 
  2394 * Improved 'oracle' command provides a type-safe interface to turn an
  2395 ML expression of type theory -> T -> term into a primitive rule of
  2396 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2397 is already included here); see also FOL/ex/IffExample.thy;
  2398 INCOMPATIBILITY.
  2399 
  2400 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2401 before); "cI" is no longer bound, use "c.intro" instead.
  2402 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2403 axclasses vs. locales.
  2404 
  2405 * Improved internal renaming of symbolic identifiers -- attach primes
  2406 instead of base 26 numbers.
  2407 
  2408 * New flag show_question_marks controls printing of leading question
  2409 marks in schematic variable names.
  2410 
  2411 * In schematic variable names, *any* symbol following \<^isub> or
  2412 \<^isup> is now treated as part of the base name.  For example, the
  2413 following works without printing of awkward ".0" indexes:
  2414 
  2415   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2416     by simp
  2417 
  2418 * Inner syntax includes (*(*nested*) comments*).
  2419 
  2420 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2421 annotations as "(00...)".
  2422 
  2423 * Clear separation of logical types and nonterminals, where the latter
  2424 may only occur in 'syntax' specifications or type abbreviations.
  2425 Before that distinction was only partially implemented via type class
  2426 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2427 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2428 exotic syntax specifications may require further adaption
  2429 (e.g. Cube/Cube.thy).
  2430 
  2431 * Removed obsolete type class "logic", use the top sort {} instead.
  2432 Note that non-logical types should be declared as 'nonterminals'
  2433 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2434 specifications.
  2435 
  2436 * Attributes 'induct' and 'cases': type or set names may now be
  2437 locally fixed variables as well.
  2438 
  2439 * Simplifier: can now control the depth to which conditional rewriting
  2440 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2441 Limit.
  2442 
  2443 * Simplifier: simplification procedures may now take the current
  2444 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2445 interface), which is very useful for calling the Simplifier
  2446 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2447 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2448 low-level mk_simproc no longer applies Logic.varify internally, to
  2449 allow for use in a context of fixed variables.
  2450 
  2451 * thin_tac now works even if the assumption being deleted contains !!
  2452 or ==>.  More generally, erule now works even if the major premise of
  2453 the elimination rule contains !! or ==>.
  2454 
  2455 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2456 
  2457 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2458 from Pure, which contains all common declarations already.  Both
  2459 theories are defined via plain Isabelle/Isar .thy files.
  2460 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2461 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2462 use isatool fixcpure to adapt your theory and ML sources.
  2463 
  2464 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2465 selections of theorems in named facts via index ranges.
  2466 
  2467 * 'print_theorems': in theory mode, really print the difference
  2468 wrt. the last state (works for interactive theory development only),
  2469 in proof mode print all local facts (cf. 'print_facts');
  2470 
  2471 * 'hide': option '(open)' hides only base names.
  2472 
  2473 * More efficient treatment of intermediate checkpoints in interactive
  2474 theory development.
  2475 
  2476 * Code generator is now invoked via code_module (incremental code
  2477 generation) and code_library (modular code generation, ML structures
  2478 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2479 must be quoted when used as identifiers.
  2480 
  2481 * New 'value' command for reading, evaluating and printing terms using
  2482 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2483 quoted when used as identifier.
  2484 
  2485 
  2486 *** Locales ***
  2487 
  2488 * New commands for the interpretation of locale expressions in
  2489 theories (1), locales (2) and proof contexts (3).  These generate
  2490 proof obligations from the expression specification.  After the
  2491 obligations have been discharged, theorems of the expression are added
  2492 to the theory, target locale or proof context.  The synopsis of the
  2493 commands is a follows:
  2494 
  2495   (1) interpretation expr inst
  2496   (2) interpretation target < expr
  2497   (3) interpret expr inst
  2498 
  2499 Interpretation in theories and proof contexts require a parameter
  2500 instantiation of terms from the current context.  This is applied to
  2501 specifications and theorems of the interpreted expression.
  2502 Interpretation in locales only permits parameter renaming through the
  2503 locale expression.  Interpretation is smart in that interpretations
  2504 that are active already do not occur in proof obligations, neither are
  2505 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2506 inspect active interpretations of a particular locale.  For details,
  2507 see the Isar Reference manual.  Examples can be found in
  2508 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2509 
  2510 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2511 'interpret' instead.
  2512 
  2513 * New context element 'constrains' for adding type constraints to
  2514 parameters.
  2515 
  2516 * Context expressions: renaming of parameters with syntax
  2517 redeclaration.
  2518 
  2519 * Locale declaration: 'includes' disallowed.
  2520 
  2521 * Proper static binding of attribute syntax -- i.e. types / terms /
  2522 facts mentioned as arguments are always those of the locale definition
  2523 context, independently of the context of later invocations.  Moreover,
  2524 locale operations (renaming and type / term instantiation) are applied
  2525 to attribute arguments as expected.
  2526 
  2527 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2528 actual attributes; rare situations may require Attrib.attribute to
  2529 embed those attributes into Attrib.src that lack concrete syntax.
  2530 Attribute implementations need to cooperate properly with the static
  2531 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2532 Attrib.XXX_thm etc. already do the right thing without further
  2533 intervention.  Only unusual applications -- such as "where" or "of"
  2534 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2535 on the context and the facts involved -- may have to assign parsed
  2536 values to argument tokens explicitly.
  2537 
  2538 * Changed parameter management in theorem generation for long goal
  2539 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2540 theorem statement in rare situations.
  2541 
  2542 * Locale inspection command 'print_locale' omits notes elements.  Use
  2543 'print_locale!' to have them included in the output.
  2544 
  2545 
  2546 *** Provers ***
  2547 
  2548 * Provers/hypsubst.ML: improved version of the subst method, for
  2549 single-step rewriting: it now works in bound variable contexts. New is
  2550 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2551 rewrite a different subterm than the original subst method, which is
  2552 still available as 'simplesubst'.
  2553 
  2554 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2555 and quasi orders.
  2556 
  2557 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2558 reflexive-transitive closure of relations.
  2559 
  2560 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2561 limit (previously hard-coded with a value of 20) user-definable.
  2562 
  2563 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2564 is peformed already.  Object-logics merely need to finish their
  2565 initial simpset configuration as before.  INCOMPATIBILITY.
  2566 
  2567 
  2568 *** HOL ***
  2569 
  2570 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2571 
  2572   syntax (epsilon)
  2573     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2574 
  2575 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2576 and x-symbol; use option '-m epsilon' to get it actually printed.
  2577 Moreover, the mathematically important symbolic identifier \<epsilon>
  2578 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2579 
  2580 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2581 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2582 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2583 support corresponding Isar calculations.
  2584 
  2585 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2586 instead of ":".
  2587 
  2588 * theory SetInterval: changed the syntax for open intervals:
  2589 
  2590   Old       New
  2591   {..n(}    {..<n}
  2592   {)n..}    {n<..}
  2593   {m..n(}   {m..<n}
  2594   {)m..n}   {m<..n}
  2595   {)m..n(}  {m<..<n}
  2596 
  2597 The old syntax is still supported but will disappear in the next
  2598 release.  For conversion use the following Emacs search and replace
  2599 patterns (these are not perfect but work quite well):
  2600 
  2601   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2602   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2603 
  2604 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2605 equalities in commutative rings; method 'algebra' provides a generic
  2606 interface.
  2607 
  2608 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2609 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2610 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2611 be a tuple pattern.
  2612 
  2613 Some new syntax forms are available:
  2614 
  2615   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2616   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2617   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2618   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2619 
  2620 The latter form "\<Sum>x < k. e" used to be based on a separate
  2621 function "Summation", which has been discontinued.
  2622 
  2623 * theory Finite_Set: in structured induction proofs, the insert case
  2624 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2625 (insert F x)'.
  2626 
  2627 * The 'refute' command has been extended to support a much larger
  2628 fragment of HOL, including axiomatic type classes, constdefs and
  2629 typedefs, inductive datatypes and recursion.
  2630 
  2631 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2632 Requires zChaff with proof generation to be installed.  See
  2633 HOL/ex/SAT_Examples.thy for examples.
  2634 
  2635 * Datatype induction via method 'induct' now preserves the name of the
  2636 induction variable. For example, when proving P(xs::'a list) by
  2637 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2638 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2639 in unstructured proof scripts.
  2640 
  2641 * Reworked implementation of records.  Improved scalability for
  2642 records with many fields, avoiding performance problems for type
  2643 inference. Records are no longer composed of nested field types, but
  2644 of nested extension types. Therefore the record type only grows linear
  2645 in the number of extensions and not in the number of fields.  The
  2646 top-level (users) view on records is preserved.  Potential
  2647 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2648 old record representation. The type generated for a record is called
  2649 <record_name>_ext_type.
  2650 
  2651 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2652 proofs triggered by a record definition or a simproc (if
  2653 quick_and_dirty is enabled).  Definitions of large records can take
  2654 quite long.
  2655 
  2656 New simproc record_upd_simproc for simplification of multiple record
  2657 updates enabled by default.  Moreover, trivial updates are also
  2658 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2659 occasionally, since simplification is more powerful by default.
  2660 
  2661 * typedef: proper support for polymorphic sets, which contain extra
  2662 type-variables in the term.
  2663 
  2664 * Simplifier: automatically reasons about transitivity chains
  2665 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2666 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2667 old proofs break occasionally as simplification may now solve more
  2668 goals than previously.
  2669 
  2670 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2671 present.  Works for all partial orders (class "order"), in particular
  2672 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2673 just like y <= x.
  2674 
  2675 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2676 bound variable or a constant then the let is unfolded.  Otherwise
  2677 first a is simplified to b, and then f b is simplified to g. If
  2678 possible we abstract b from g arriving at "let x = b in h x",
  2679 otherwise we unfold the let and arrive at g.  The simproc can be
  2680 enabled/disabled by the reference use_let_simproc.  Potential
  2681 INCOMPATIBILITY since simplification is more powerful by default.
  2682 
  2683 * Classical reasoning: the meson method now accepts theorems as arguments.
  2684 
  2685 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2686 jobs to provide advice on the provability of subgoals.
  2687 
  2688 * Theory OrderedGroup and Ring_and_Field: various additions and
  2689 improvements to faciliate calculations involving equalities and
  2690 inequalities.
  2691 
  2692 The following theorems have been eliminated or modified
  2693 (INCOMPATIBILITY):
  2694 
  2695   abs_eq             now named abs_of_nonneg
  2696   abs_of_ge_0        now named abs_of_nonneg
  2697   abs_minus_eq       now named abs_of_nonpos
  2698   imp_abs_id         now named abs_of_nonneg
  2699   imp_abs_neg_id     now named abs_of_nonpos
  2700   mult_pos           now named mult_pos_pos
  2701   mult_pos_le        now named mult_nonneg_nonneg
  2702   mult_pos_neg_le    now named mult_nonneg_nonpos
  2703   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2704   mult_neg           now named mult_neg_neg
  2705   mult_neg_le        now named mult_nonpos_nonpos
  2706 
  2707 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2708      
  2709      zero_le_square
  2710      not_square_less_zero 
  2711 
  2712   The following lemmas have been deleted from Real/RealPow:
  2713   
  2714      realpow_zero_zero
  2715      realpow_two
  2716      realpow_less
  2717      zero_le_power
  2718      realpow_two_le
  2719      abs_realpow_two
  2720      realpow_two_abs     
  2721 
  2722 * Theory Parity: added rules for simplifying exponents.
  2723 
  2724 * Theory List:
  2725 
  2726 The following theorems have been eliminated or modified
  2727 (INCOMPATIBILITY):
  2728 
  2729   list_all_Nil       now named list_all.simps(1)
  2730   list_all_Cons      now named list_all.simps(2)
  2731   list_all_conv      now named list_all_iff
  2732   set_mem_eq         now named mem_iff
  2733 
  2734 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  2735 asymptotic "big O" calculations.  See the notes in BigO.thy.
  2736 
  2737 
  2738 *** HOL-Complex ***
  2739 
  2740 * Theory RealDef: better support for embedding natural numbers and
  2741 integers in the reals.
  2742 
  2743 The following theorems have been eliminated or modified
  2744 (INCOMPATIBILITY):
  2745 
  2746   exp_ge_add_one_self  now requires no hypotheses
  2747   real_of_int_add      reversed direction of equality (use [symmetric])
  2748   real_of_int_minus    reversed direction of equality (use [symmetric])
  2749   real_of_int_diff     reversed direction of equality (use [symmetric])
  2750   real_of_int_mult     reversed direction of equality (use [symmetric])
  2751 
  2752 * Theory RComplete: expanded support for floor and ceiling functions.
  2753 
  2754 * Theory Ln is new, with properties of the natural logarithm
  2755 
  2756 * Hyperreal: There is a new type constructor "star" for making
  2757 nonstandard types.  The old type names are now type synonyms:
  2758 
  2759   hypreal = real star
  2760   hypnat = nat star
  2761   hcomplex = complex star
  2762 
  2763 * Hyperreal: Many groups of similarly-defined constants have been
  2764 replaced by polymorphic versions (INCOMPATIBILITY):
  2765 
  2766   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2767 
  2768   starset      <-- starsetNat, starsetC
  2769   *s*          <-- *sNat*, *sc*
  2770   starset_n    <-- starsetNat_n, starsetC_n
  2771   *sn*         <-- *sNatn*, *scn*
  2772   InternalSets <-- InternalNatSets, InternalCSets
  2773 
  2774   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2775   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2776   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2777   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2778   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2779 
  2780 * Hyperreal: Many type-specific theorems have been removed in favor of
  2781 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2782 
  2783   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2784   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2785   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2786   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2787   right_minus <-- hypreal_add_minus
  2788   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2789   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2790   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2791   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2792   mult_1_right <-- hcomplex_mult_one_right
  2793   mult_zero_left <-- hcomplex_mult_zero_left
  2794   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2795   right_distrib <-- hypnat_add_mult_distrib2
  2796   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2797   right_inverse <-- hypreal_mult_inverse
  2798   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2799   order_refl <-- {hypreal,hypnat}_le_refl
  2800   order_trans <-- {hypreal,hypnat}_le_trans
  2801   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2802   order_less_le <-- {hypreal,hypnat}_less_le
  2803   linorder_linear <-- {hypreal,hypnat}_le_linear
  2804   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2805   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2806   add_nonneg_nonneg <-- hypreal_le_add_order
  2807 
  2808 * Hyperreal: Separate theorems having to do with type-specific
  2809 versions of constants have been merged into theorems that apply to the
  2810 new polymorphic constants (INCOMPATIBILITY):
  2811 
  2812   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2813   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2814   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2815   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2816   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2817   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2818   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2819   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2820   STAR_diff <-- {STAR,STARC}_diff
  2821   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2822     STARC_hcomplex_of_complex}_image_subset
  2823   starset_n_Un <-- starset{Nat,C}_n_Un
  2824   starset_n_Int <-- starset{Nat,C}_n_Int
  2825   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2826   starset_n_diff <-- starset{Nat,C}_n_diff
  2827   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2828   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2829   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2830   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2831   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2832   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2833   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2834   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2835   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2836   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2837   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2838   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2839   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2840   starfun_diff <-- starfun{C,RC,CR}_diff
  2841   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2842   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2843   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2844   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2845   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2846   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2847   starfun_Id <-- starfunC_Id
  2848   starfun_approx <-- starfun{Nat,CR}_approx
  2849   starfun_capprox <-- starfun{C,RC}_capprox
  2850   starfun_abs <-- starfunNat_rabs
  2851   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2852   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2853   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2854   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2855   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2856   starfun_add_approx <-- starfunCR_add_approx
  2857   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2858   starfun_divide <-- starfun{C,CR,RC}_divide
  2859   starfun_n <-- starfun{Nat,C}_n
  2860   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2861   starfun_n_add <-- starfun{Nat,C}_n_add
  2862   starfun_n_add_minus <-- starfunNat_n_add_minus
  2863   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2864   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2865   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2866 
  2867   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2868   star_n_minus <-- {hypreal,hcomplex}_minus
  2869   star_n_diff <-- {hypreal,hcomplex}_diff
  2870   star_n_mult <-- {hypreal,hcomplex}_mult
  2871   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2872   star_n_le <-- {hypreal,hypnat}_le
  2873   star_n_less <-- {hypreal,hypnat}_less
  2874   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2875   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2876   star_n_abs <-- hypreal_hrabs
  2877   star_n_divide <-- hcomplex_divide
  2878 
  2879   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2880   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2881   star_of_diff <-- hypreal_of_real_diff
  2882   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2883   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2884   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2885   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2886   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2887   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2888   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2889   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2890   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2891   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2892   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2893   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2894   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2895   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2896   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2897   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2898   star_of_power <-- hypreal_of_real_power
  2899   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2900 
  2901 * Hyperreal: new method "transfer" that implements the transfer
  2902 principle of nonstandard analysis. With a subgoal that mentions
  2903 nonstandard types like "'a star", the command "apply transfer"
  2904 replaces it with an equivalent one that mentions only standard types.
  2905 To be successful, all free variables must have standard types; non-
  2906 standard variables must have explicit universal quantifiers.
  2907 
  2908 * Hyperreal: A theory of Taylor series.
  2909 
  2910 
  2911 *** HOLCF ***
  2912 
  2913 * Discontinued special version of 'constdefs' (which used to support
  2914 continuous functions) in favor of the general Pure one with full
  2915 type-inference.
  2916 
  2917 * New simplification procedure for solving continuity conditions; it
  2918 is much faster on terms with many nested lambda abstractions (cubic
  2919 instead of exponential time).
  2920 
  2921 * New syntax for domain package: selector names are now optional.
  2922 Parentheses should be omitted unless argument is lazy, for example:
  2923 
  2924   domain 'a stream = cons "'a" (lazy "'a stream")
  2925 
  2926 * New command 'fixrec' for defining recursive functions with pattern
  2927 matching; defining multiple functions with mutual recursion is also
  2928 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2929 sinr, or any data constructor defined by the domain package. The given
  2930 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2931 syntax and examples.
  2932 
  2933 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2934 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2935 but the proof obligation additionally includes an admissibility
  2936 requirement. The packages generate instances of class cpo or pcpo,
  2937 with continuity and strictness theorems for Rep and Abs.
  2938 
  2939 * HOLCF: Many theorems have been renamed according to a more standard naming
  2940 scheme (INCOMPATIBILITY):
  2941 
  2942   foo_inject:  "foo$x = foo$y ==> x = y"
  2943   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2944   foo_less:    "(foo$x << foo$y) = (x << y)"
  2945   foo_strict:  "foo$UU = UU"
  2946   foo_defined: "... ==> foo$x ~= UU"
  2947   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2948 
  2949 
  2950 *** ZF ***
  2951 
  2952 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2953 including the First Isomorphism Theorem (on quotienting by the kernel
  2954 of a homomorphism).
  2955 
  2956 * ZF/Simplifier: install second copy of type solver that actually
  2957 makes use of TC rules declared to Isar proof contexts (or locales);
  2958 the old version is still required for ML proof scripts.
  2959 
  2960 
  2961 *** Cube ***
  2962 
  2963 * Converted to Isar theory format; use locales instead of axiomatic
  2964 theories.
  2965 
  2966 
  2967 *** ML ***
  2968 
  2969 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2970 for ||>, ||>>, |>>,
  2971 
  2972 * Pure/library.ML no longer defines its own option datatype, but uses
  2973 that of the SML basis, which has constructors NONE and SOME instead of
  2974 None and Some, as well as exception Option.Option instead of OPTION.
  2975 The functions the, if_none, is_some, is_none have been adapted
  2976 accordingly, while Option.map replaces apsome.
  2977 
  2978 * Pure/library.ML: the exception LIST has been given up in favour of
  2979 the standard exceptions Empty and Subscript, as well as
  2980 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2981 superceded by the standard hd and tl functions etc.
  2982 
  2983 A number of basic list functions are no longer exported to the ML
  2984 toplevel, as they are variants of predefined functions.  The following
  2985 suggests how one can translate existing code:
  2986 
  2987     rev_append xs ys = List.revAppend (xs, ys)
  2988     nth_elem (i, xs) = List.nth (xs, i)
  2989     last_elem xs = List.last xs
  2990     flat xss = List.concat xss
  2991     seq fs = List.app fs
  2992     partition P xs = List.partition P xs
  2993     mapfilter f xs = List.mapPartial f xs
  2994 
  2995 * Pure/library.ML: several combinators for linear functional
  2996 transformations, notably reverse application and composition:
  2997 
  2998   x |> f                f #> g
  2999   (x, y) |-> f          f #-> g
  3000 
  3001 * Pure/library.ML: introduced/changed precedence of infix operators:
  3002 
  3003   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3004   infix 2 ?;
  3005   infix 3 o oo ooo oooo;
  3006   infix 4 ~~ upto downto;
  3007 
  3008 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3009 infix operators.
  3010 
  3011 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3012 fold_map support linear functional transformations and nesting.  For
  3013 example:
  3014 
  3015   fold f [x1, ..., xN] y =
  3016     y |> f x1 |> ... |> f xN
  3017 
  3018   (fold o fold) f [xs1, ..., xsN] y =
  3019     y |> fold f xs1 |> ... |> fold f xsN
  3020 
  3021   fold f [x1, ..., xN] =
  3022     f x1 #> ... #> f xN
  3023 
  3024   (fold o fold) f [xs1, ..., xsN] =
  3025     fold f xs1 #> ... #> fold f xsN
  3026 
  3027 * Pure/library.ML: the following selectors on type 'a option are
  3028 available:
  3029 
  3030   the:               'a option -> 'a  (*partial*)
  3031   these:             'a option -> 'a  where 'a = 'b list
  3032   the_default: 'a -> 'a option -> 'a
  3033   the_list:          'a option -> 'a list
  3034 
  3035 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3036 basic operations for association lists, following natural argument
  3037 order; moreover the explicit equality predicate passed here avoids
  3038 potentially expensive polymorphic runtime equality checks.
  3039 The old functions may be expressed as follows:
  3040 
  3041   assoc = uncurry (AList.lookup (op =))
  3042   assocs = these oo AList.lookup (op =)
  3043   overwrite = uncurry (AList.update (op =)) o swap
  3044 
  3045 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3046 
  3047   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3048   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3049 
  3050 replacing make_keylist and keyfilter (occassionally used)
  3051 Naive rewrites:
  3052 
  3053   make_keylist = AList.make
  3054   keyfilter = AList.find (op =)
  3055 
  3056 * eq_fst and eq_snd now take explicit equality parameter, thus
  3057   avoiding eqtypes. Naive rewrites:
  3058 
  3059     eq_fst = eq_fst (op =)
  3060     eq_snd = eq_snd (op =)
  3061 
  3062 * Removed deprecated apl and apr (rarely used).
  3063   Naive rewrites:
  3064 
  3065     apl (n, op) =>>= curry op n
  3066     apr (op, m) =>>= fn n => op (n, m)
  3067 
  3068 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3069 provides a reasonably efficient light-weight implementation of sets as
  3070 lists.
  3071 
  3072 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3073 few new operations; existing lookup and update are now curried to
  3074 follow natural argument order (for use with fold etc.);
  3075 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3076 
  3077 * Pure/General: output via the Isabelle channels of
  3078 writeln/warning/error etc. is now passed through Output.output, with a
  3079 hook for arbitrary transformations depending on the print_mode
  3080 (cf. Output.add_mode -- the first active mode that provides a output
  3081 function wins).  Already formatted output may be embedded into further
  3082 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3083 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3084 accommodate easy composition of diagnostic messages etc.  Programmers
  3085 rarely need to care about Output.output or Output.raw at all, with
  3086 some notable exceptions: Output.output is required when bypassing the
  3087 standard channels (writeln etc.), or in token translations to produce
  3088 properly formatted results; Output.raw is required when capturing
  3089 already output material that will eventually be presented to the user
  3090 a second time.  For the default print mode, both Output.output and
  3091 Output.raw have no effect.
  3092 
  3093 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3094 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3095 cumulative results are displayed at the end of a batch session.
  3096 
  3097 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3098 replaced by File.platform_path and File.shell_path (with appropriate
  3099 hooks).  This provides a clean interface for unusual systems where the
  3100 internal and external process view of file names are different.
  3101 
  3102 * Pure: more efficient orders for basic syntactic entities: added
  3103 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3104 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3105 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3106 orders now -- potential INCOMPATIBILITY for code that depends on a
  3107 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3108 Library.sort_strings on result).
  3109 
  3110 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3111 fold_types traverse types/terms from left to right, observing natural
  3112 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3113 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3114 
  3115 * Pure: name spaces have been refined, with significant changes of the
  3116 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3117 to extern(_table).  The plain name entry path is superceded by a
  3118 general 'naming' context, which also includes the 'policy' to produce
  3119 a fully qualified name and external accesses of a fully qualified
  3120 name; NameSpace.extend is superceded by context dependent
  3121 Sign.declare_name.  Several theory and proof context operations modify
  3122 the naming context.  Especially note Theory.restore_naming and
  3123 ProofContext.restore_naming to get back to a sane state; note that
  3124 Theory.add_path is no longer sufficient to recover from
  3125 Theory.absolute_path in particular.
  3126 
  3127 * Pure: new flags short_names (default false) and unique_names
  3128 (default true) for controlling output of qualified names.  If
  3129 short_names is set, names are printed unqualified.  If unique_names is
  3130 reset, the name prefix is reduced to the minimum required to achieve
  3131 the original result when interning again, even if there is an overlap
  3132 with earlier declarations.
  3133 
  3134 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3135 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3136 (useful for printing error messages).  INCOMPATIBILITY.
  3137 
  3138 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3139 Theory.theory are now identified, referring to the universal
  3140 Context.theory (see Pure/context.ML).  Actual signature and theory
  3141 content is managed as theory data.  The old code and interfaces were
  3142 spread over many files and structures; the new arrangement introduces
  3143 considerable INCOMPATIBILITY to gain more clarity:
  3144 
  3145   Context -- theory management operations (name, identity, inclusion,
  3146     parents, ancestors, merge, etc.), plus generic theory data;
  3147 
  3148   Sign -- logical signature and syntax operations (declaring consts,
  3149     types, etc.), plus certify/read for common entities;
  3150 
  3151   Theory -- logical theory operations (stating axioms, definitions,
  3152     oracles), plus a copy of logical signature operations (consts,
  3153     types, etc.); also a few basic management operations (Theory.copy,
  3154     Theory.merge, etc.)
  3155 
  3156 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3157 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3158 for convenience -- they merely return the theory.
  3159 
  3160 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3161 
  3162 * Pure: the Isar proof context type is already defined early in Pure
  3163 as Context.proof (note that ProofContext.context and Proof.context are
  3164 aliases, where the latter is the preferred name).  This enables other
  3165 Isabelle components to refer to that type even before Isar is present.
  3166 
  3167 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3168 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3169 any of these kinds.  For example, Sign.intern typeK is now
  3170 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3171 Theory.hide_types.  Also note that former
  3172 Theory.hide_classes/types/consts are now
  3173 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3174 internalize their arguments!  INCOMPATIBILITY.
  3175 
  3176 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3177 datatype thmref (with constructors Name and NameSelection) instead of
  3178 plain string -- INCOMPATIBILITY;
  3179 
  3180 * Pure: cases produced by proof methods specify options, where NONE
  3181 means to remove case bindings -- INCOMPATIBILITY in
  3182 (RAW_)METHOD_CASES.
  3183 
  3184 * Pure: the following operations retrieve axioms or theorems from a
  3185 theory node or theory hierarchy, respectively:
  3186 
  3187   Theory.axioms_of: theory -> (string * term) list
  3188   Theory.all_axioms_of: theory -> (string * term) list
  3189   PureThy.thms_of: theory -> (string * thm) list
  3190   PureThy.all_thms_of: theory -> (string * thm) list
  3191 
  3192 * Pure: print_tac now outputs the goal through the trace channel.
  3193 
  3194 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3195 Reference Toplevel.debug (default false) controls detailed printing
  3196 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3197 controls execution profiling -- set to 1 for time and 2 for space
  3198 (both increase the runtime).
  3199 
  3200 * Isar session: The initial use of ROOT.ML is now always timed,
  3201 i.e. the log will show the actual process times, in contrast to the
  3202 elapsed wall-clock time that the outer shell wrapper produces.
  3203 
  3204 * Simplifier: improved handling of bound variables (nameless
  3205 representation, avoid allocating new strings).  Simprocs that invoke
  3206 the Simplifier recursively should use Simplifier.inherit_bounds to
  3207 avoid local name clashes.  Failure to do so produces warnings
  3208 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3209 for further details.
  3210 
  3211 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3212 bindings for all theorems stored within a given theory; this may help
  3213 in porting non-Isar theories to Isar ones, while keeping ML proof
  3214 scripts for the time being.
  3215 
  3216 * ML operator HTML.with_charset specifies the charset begin used for
  3217 generated HTML files.  For example:
  3218 
  3219   HTML.with_charset "utf-8" use_thy "Hebrew";
  3220   HTML.with_charset "utf-8" use_thy "Chinese";
  3221 
  3222 
  3223 *** System ***
  3224 
  3225 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3226 isabelle, isatool etc.).
  3227 
  3228 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3229 isatool doc, isatool mkdir, display_drafts etc.).
  3230 
  3231 * isatool usedir: option -f allows specification of the ML file to be
  3232 used by Isabelle; default is ROOT.ML.
  3233 
  3234 * New isatool version outputs the version identifier of the Isabelle
  3235 distribution being used.
  3236 
  3237 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3238 (containing Boolean satisfiability problems) into Isabelle/HOL
  3239 theories.
  3240 
  3241 
  3242 
  3243 New in Isabelle2004 (April 2004)
  3244 --------------------------------
  3245 
  3246 *** General ***
  3247 
  3248 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3249   Replaces linorder.ML.
  3250 
  3251 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3252   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3253   (\<a>...\<z>), are now considered normal letters, and can therefore
  3254   be used anywhere where an ASCII letter (a...zA...Z) has until
  3255   now. COMPATIBILITY: This obviously changes the parsing of some
  3256   terms, especially where a symbol has been used as a binder, say
  3257   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3258   as an identifier.  Fix it by inserting a space around former
  3259   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3260   existing theory and ML files.
  3261 
  3262 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3263 
  3264 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3265   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3266   a normal (but invisible) letter. For multiple letter subscripts repeat
  3267   \<^isub> like this: x\<^isub>1\<^isub>2.
  3268 
  3269 * Pure: There are now sub-/superscripts that can span more than one
  3270   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3271   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3272   superscript. The new control characters are not identifier parts.
  3273 
  3274 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3275   content of "..." to the latex file instead of \isacntrl... . The "..."
  3276   may consist of any printable characters excluding the end bracket >.
  3277 
  3278 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3279   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3280   declare constants "final", which prevents their being given a definition
  3281   later.  It is useful for constants whose behaviour is fixed axiomatically
  3282   rather than definitionally, such as the meta-logic connectives.
  3283 
  3284 * Pure: 'instance' now handles general arities with general sorts
  3285   (i.e. intersections of classes),
  3286 
  3287 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3288   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3289   It can be changed to alter the colors/layout of generated pages.
  3290 
  3291 
  3292 *** Isar ***
  3293 
  3294 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3295   cut_tac, subgoal_tac and thin_tac:
  3296   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3297     locales are no longer forced to write Isar proof scripts.
  3298     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3299     emulations.
  3300   - INCOMPATIBILITY: names of variables to be instantiated may no
  3301     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3302     This is consistent with the instantiation attribute "where".
  3303 
  3304 * Attributes "where" and "of":
  3305   - Now take type variables of instantiated theorem into account when reading
  3306     the instantiation string.  This fixes a bug that caused instantiated
  3307     theorems to have too special types in some circumstances.
  3308   - "where" permits explicit instantiations of type variables.
  3309 
  3310 * Calculation commands "moreover" and "also" no longer interfere with
  3311   current facts ("this"), admitting arbitrary combinations with "then"
  3312   and derived forms.
  3313 
  3314 * Locales:
  3315   - Goal statements involving the context element "includes" no longer
  3316     generate theorems with internal delta predicates (those ending on
  3317     "_axioms") in the premise.
  3318     Resolve particular premise with <locale>.intro to obtain old form.
  3319   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3320     specification and "includes" elements in goal statement.
  3321   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3322     [intro?] and [elim?] (respectively) by default.
  3323   - Experimental command for instantiation of locales in proof contexts:
  3324         instantiate <label>[<attrs>]: <loc>
  3325     Instantiates locale <loc> and adds all its theorems to the current context
  3326     taking into account their attributes.  Label and attrs are optional
  3327     modifiers, like in theorem declarations.  If present, names of
  3328     instantiated theorems are qualified with <label>, and the attributes
  3329     <attrs> are applied after any attributes these theorems might have already.
  3330       If the locale has assumptions, a chained fact of the form
  3331     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3332     are derived.  The command does not support old-style locales declared
  3333     with "locale (open)".
  3334       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3335 
  3336 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3337   (Isar) contexts.
  3338 
  3339 
  3340 *** HOL ***
  3341 
  3342 * Proof import: new image HOL4 contains the imported library from
  3343   the HOL4 system with about 2500 theorems. It is imported by
  3344   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3345   can be used like any other Isabelle image.  See
  3346   HOL/Import/HOL/README for more information.
  3347 
  3348 * Simplifier:
  3349   - Much improved handling of linear and partial orders.
  3350     Reasoners for linear and partial orders are set up for type classes
  3351     "linorder" and "order" respectively, and are added to the default simpset
  3352     as solvers.  This means that the simplifier can build transitivity chains
  3353     to solve goals from the assumptions.
  3354   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3355     of blast or auto after simplification become unnecessary because the goal
  3356     is solved by simplification already.
  3357 
  3358 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3359     all proved in axiomatic type classes for semirings, rings and fields.
  3360 
  3361 * Numerics:
  3362   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3363     now formalized using the Ring_and_Field theory mentioned above.
  3364   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3365     than before, because now they are set up once in a generic manner.
  3366   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3367     Look for the general versions in Ring_and_Field (and Power if they concern
  3368     exponentiation).
  3369 
  3370 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3371 
  3372 * Records:
  3373   - Record types are now by default printed with their type abbreviation
  3374     instead of the list of all field types. This can be configured via
  3375     the reference "print_record_type_abbr".
  3376   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3377     (not enabled by default).
  3378   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3379     EX x. x = sel r to True (not enabled by default).
  3380   - Tactic "record_split_simp_tac" to split and simplify records added.
  3381 
  3382 * 'specification' command added, allowing for definition by
  3383   specification.  There is also an 'ax_specification' command that
  3384   introduces the new constants axiomatically.
  3385 
  3386 * arith(_tac) is now able to generate counterexamples for reals as well.
  3387 
  3388 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3389 
  3390 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3391   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3392 
  3393 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3394   matrix theory to linear programming.
  3395 
  3396 * Unions and Intersections:
  3397   The latex output syntax of UN and INT has been changed
  3398   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3399   i.e. the index formulae has become a subscript.
  3400   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3401 
  3402 * Unions and Intersections over Intervals:
  3403   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3404   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3405   like in normal math, and corresponding versions for < and for intersection.
  3406 
  3407 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3408   lexicographic dictonary ordering has been added as "lexord".
  3409 
  3410 * ML: the legacy theory structures Int and List have been removed. They had
  3411   conflicted with ML Basis Library structures having the same names.
  3412 
  3413 * 'refute' command added to search for (finite) countermodels.  Only works
  3414   for a fragment of HOL.  The installation of an external SAT solver is
  3415   highly recommended.  See "HOL/Refute.thy" for details.
  3416 
  3417 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3418   formulae under an assignment of free variables to random values.
  3419   In contrast to 'refute', it can deal with inductive datatypes,
  3420   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3421   for examples.
  3422 
  3423 
  3424 *** HOLCF ***
  3425 
  3426 * Streams now come with concatenation and are part of the HOLCF image
  3427 
  3428 
  3429 
  3430 New in Isabelle2003 (May 2003)
  3431 ------------------------------
  3432 
  3433 *** General ***
  3434 
  3435 * Provers/simplifier:
  3436 
  3437   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3438     Assumptions are now subject to complete mutual simplification,
  3439     not just from left to right. The simplifier now preserves
  3440     the order of assumptions.
  3441 
  3442     Potential INCOMPATIBILITY:
  3443 
  3444     -- simp sometimes diverges where the old version did
  3445        not, e.g. invoking simp on the goal
  3446 
  3447         [| P (f x); y = x; f x = f y |] ==> Q
  3448 
  3449        now gives rise to the infinite reduction sequence
  3450 
  3451         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3452 
  3453        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3454        kind of problem.
  3455 
  3456     -- Tactics combining classical reasoner and simplification (such as auto)
  3457        are also affected by this change, because many of them rely on
  3458        simp. They may sometimes diverge as well or yield a different numbers
  3459        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3460        in case of problems. Sometimes subsequent calls to the classical
  3461        reasoner will fail because a preceeding call to the simplifier too
  3462        eagerly simplified the goal, e.g. deleted redundant premises.
  3463 
  3464   - The simplifier trace now shows the names of the applied rewrite rules
  3465 
  3466   - You can limit the number of recursive invocations of the simplifier
  3467     during conditional rewriting (where the simplifie tries to solve the
  3468     conditions before applying the rewrite rule):
  3469     ML "simp_depth_limit := n"
  3470     where n is an integer. Thus you can force termination where previously
  3471     the simplifier would diverge.
  3472 
  3473   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3474 
  3475   - No longer aborts on failed congruence proof.  Instead, the
  3476     congruence is ignored.
  3477 
  3478 * Pure: New generic framework for extracting programs from constructive
  3479   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3480   as HOL/Extraction for some case studies.
  3481 
  3482 * Pure: The main goal of the proof state is no longer shown by default, only
  3483 the subgoals. This behaviour is controlled by a new flag.
  3484    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3485 (ML: Proof.show_main_goal).
  3486 
  3487 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3488 rules whose conclusion matches subgoal 1:
  3489       PG menu: Isabelle/Isar -> Show me -> matching rules
  3490 The rules are ordered by how closely they match the subgoal.
  3491 In particular, rules that solve a subgoal outright are displayed first
  3492 (or rather last, the way they are printed).
  3493 (ML: ProofGeneral.print_intros())
  3494 
  3495 * Pure: New flag trace_unify_fail causes unification to print
  3496 diagnostic information (PG: in trace buffer) when it fails. This is
  3497 useful for figuring out why single step proofs like rule, erule or
  3498 assumption failed.
  3499 
  3500 * Pure: Locale specifications now produce predicate definitions
  3501 according to the body of text (covering assumptions modulo local
  3502 definitions); predicate "loc_axioms" covers newly introduced text,
  3503 while "loc" is cumulative wrt. all included locale expressions; the
  3504 latter view is presented only on export into the global theory
  3505 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3506 on the old view without predicates;
  3507 
  3508 * Pure: predefined locales "var" and "struct" are useful for sharing
  3509 parameters (as in CASL, for example); just specify something like
  3510 ``var x + var y + struct M'' as import;
  3511 
  3512 * Pure: improved thms_containing: proper indexing of facts instead of
  3513 raw theorems; check validity of results wrt. current name space;
  3514 include local facts of proof configuration (also covers active
  3515 locales), cover fixed variables in index; may use "_" in term
  3516 specification; an optional limit for the number of printed facts may
  3517 be given (the default is 40);
  3518 
  3519 * Pure: disallow duplicate fact bindings within new-style theory files
  3520 (batch-mode only);
  3521 
  3522 * Provers: improved induct method: assumptions introduced by case
  3523 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3524 the goal statement); "foo" still refers to all facts collectively;
  3525 
  3526 * Provers: the function blast.overloaded has been removed: all constants
  3527 are regarded as potentially overloaded, which improves robustness in exchange
  3528 for slight decrease in efficiency;
  3529 
  3530 * Provers/linorder: New generic prover for transitivity reasoning over
  3531 linear orders.  Note: this prover is not efficient!
  3532 
  3533 * Isar: preview of problems to finish 'show' now produce an error
  3534 rather than just a warning (in interactive mode);
  3535 
  3536 
  3537 *** HOL ***
  3538 
  3539 * arith(_tac)
  3540 
  3541  - Produces a counter example if it cannot prove a goal.
  3542    Note that the counter example may be spurious if the goal is not a formula
  3543    of quantifier-free linear arithmetic.
  3544    In ProofGeneral the counter example appears in the trace buffer.
  3545 
  3546  - Knows about div k and mod k where k is a numeral of type nat or int.
  3547 
  3548  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3549    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3550    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3551 
  3552 * simp's arithmetic capabilities have been enhanced a bit: it now
  3553 takes ~= in premises into account (by performing a case split);
  3554 
  3555 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3556 are distributed over a sum of terms;
  3557 
  3558 * New tactic "trans_tac" and method "trans" instantiate
  3559 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3560 "<=", "<" and "=").
  3561 
  3562 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3563 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3564 
  3565 * 'typedef' command has new option "open" to suppress the set
  3566 definition;
  3567 
  3568 * functions Min and Max on finite sets have been introduced (theory
  3569 Finite_Set);
  3570 
  3571 * attribute [symmetric] now works for relations as well; it turns
  3572 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3573 
  3574 * induct over a !!-quantified statement (say !!x1..xn):
  3575   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3576 
  3577 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3578 %x. None. Warning: empty_def now refers to the previously hidden definition
  3579 of the empty set.
  3580 
  3581 * Algebra: formalization of classical algebra.  Intended as base for
  3582 any algebraic development in Isabelle.  Currently covers group theory
  3583 (up to Sylow's theorem) and ring theory (Universal Property of
  3584 Univariate Polynomials).  Contributions welcome;
  3585 
  3586 * GroupTheory: deleted, since its material has been moved to Algebra;
  3587 
  3588 * Complex: new directory of the complex numbers with numeric constants,
  3589 nonstandard complex numbers, and some complex analysis, standard and
  3590 nonstandard (Jacques Fleuriot);
  3591 
  3592 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3593 
  3594 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3595 Fleuriot);
  3596 
  3597 * Real/HahnBanach: updated and adapted to locales;
  3598 
  3599 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3600 Gray and Kramer);
  3601 
  3602 * UNITY: added the Meier-Sanders theory of progress sets;
  3603 
  3604 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3605 as abstract algorithms, instantiated to the JVM;
  3606 
  3607 * Bali: Java source language formalization. Type system, operational
  3608 semantics, axiomatic semantics. Supported language features:
  3609 classes, interfaces, objects,virtual methods, static methods,
  3610 static/instance fields, arrays, access modifiers, definite
  3611 assignment, exceptions.
  3612 
  3613 
  3614 *** ZF ***
  3615 
  3616 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3617 universe, etc.);
  3618 
  3619 * Main ZF: virtually all theories converted to new-style format;
  3620 
  3621 
  3622 *** ML ***
  3623 
  3624 * Pure: Tactic.prove provides sane interface for internal proofs;
  3625 omits the infamous "standard" operation, so this is more appropriate
  3626 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3627 
  3628 * Pure: improved error reporting of simprocs;
  3629 
  3630 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3631 up simprocs;
  3632 
  3633 
  3634 *** Document preparation ***
  3635 
  3636 * uses \par instead of \\ for line breaks in theory text. This may
  3637 shift some page breaks in large documents. To get the old behaviour
  3638 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3639 
  3640 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3641 other packages
  3642 
  3643 * \<euro> now needs package babel/greek instead of marvosym (which
  3644 broke \Rightarrow)
  3645 
  3646 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3647 textcomp package)
  3648 
  3649 
  3650 
  3651 New in Isabelle2002 (March 2002)
  3652 --------------------------------
  3653 
  3654 *** Document preparation ***
  3655 
  3656 * greatly simplified document preparation setup, including more
  3657 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3658 instructive isatool mkdir; users should basically be able to get
  3659 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3660 users may run a separate document processing stage manually like this:
  3661 "isatool usedir -D output HOL Test && isatool document Test/output";
  3662 
  3663 * theory dependency graph may now be incorporated into documents;
  3664 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3665 with \includegraphics of LaTeX;
  3666 
  3667 * proper spacing of consecutive markup elements, especially text
  3668 blocks after section headings;
  3669 
  3670 * support bold style (for single symbols only), input syntax is like
  3671 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3672 
  3673 * \<bullet> is now output as bold \cdot by default, which looks much
  3674 better in printed text;
  3675 
  3676 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3677 note that these symbols are currently unavailable in Proof General /
  3678 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3679 
  3680 * isatool latex no longer depends on changed TEXINPUTS, instead
  3681 isatool document copies the Isabelle style files to the target
  3682 location;
  3683 
  3684 
  3685 *** Isar ***
  3686 
  3687 * Pure/Provers: improved proof by cases and induction;
  3688   - 'case' command admits impromptu naming of parameters (such as
  3689     "case (Suc n)");
  3690   - 'induct' method divinates rule instantiation from the inductive
  3691     claim; no longer requires excessive ?P bindings for proper
  3692     instantiation of cases;
  3693   - 'induct' method properly enumerates all possibilities of set/type
  3694     rules; as a consequence facts may be also passed through *type*
  3695     rules without further ado;
  3696   - 'induct' method now derives symbolic cases from the *rulified*
  3697     rule (before it used to rulify cases stemming from the internal
  3698     atomized version); this means that the context of a non-atomic
  3699     statement becomes is included in the hypothesis, avoiding the
  3700     slightly cumbersome show "PROP ?case" form;
  3701   - 'induct' may now use elim-style induction rules without chaining
  3702     facts, using ``missing'' premises from the goal state; this allows
  3703     rules stemming from inductive sets to be applied in unstructured
  3704     scripts, while still benefitting from proper handling of non-atomic
  3705     statements; NB: major inductive premises need to be put first, all
  3706     the rest of the goal is passed through the induction;
  3707   - 'induct' proper support for mutual induction involving non-atomic
  3708     rule statements (uses the new concept of simultaneous goals, see
  3709     below);
  3710   - append all possible rule selections, but only use the first
  3711     success (no backtracking);
  3712   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3713   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3714   - added 'print_induct_rules' (covered by help item in recent Proof
  3715     General versions);
  3716   - moved induct/cases attributes to Pure, methods to Provers;
  3717   - generic method setup instantiated for FOL and HOL;
  3718 
  3719 * Pure: support multiple simultaneous goal statements, for example
  3720 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3721 meta-level mechanism, this acts as if several individual goals had
  3722 been stated separately; in particular common proof methods need to be
  3723 repeated in order to cover all claims; note that a single elimination
  3724 step is *not* sufficient to establish the two conjunctions, so this
  3725 fails:
  3726 
  3727   assume "A & B" then have A and B ..   (*".." fails*)
  3728 
  3729 better use "obtain" in situations as above; alternative refer to
  3730 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  3731 
  3732 * Pure: proper integration with ``locales''; unlike the original
  3733 version by Florian Kammller, Isar locales package high-level proof
  3734 contexts rather than raw logical ones (e.g. we admit to include
  3735 attributes everywhere); operations on locales include merge and
  3736 rename; support for implicit arguments (``structures''); simultaneous
  3737 type-inference over imports and text; see also HOL/ex/Locales.thy for
  3738 some examples;
  3739 
  3740 * Pure: the following commands have been ``localized'', supporting a
  3741 target locale specification "(in name)": 'lemma', 'theorem',
  3742 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  3743 stored both within the locale and at the theory level (exported and
  3744 qualified by the locale name);
  3745 
  3746 * Pure: theory goals may now be specified in ``long'' form, with
  3747 ad-hoc contexts consisting of arbitrary locale elements. for example
  3748 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  3749 definitions may be given, too); the result is a meta-level rule with
  3750 the context elements being discharged in the obvious way;
  3751 
  3752 * Pure: new proof command 'using' allows to augment currently used
  3753 facts after a goal statement ('using' is syntactically analogous to
  3754 'apply', but acts on the goal's facts only); this allows chained facts
  3755 to be separated into parts given before and after a claim, as in
  3756 ``from a and b have C using d and e <proof>'';
  3757 
  3758 * Pure: renamed "antecedent" case to "rule_context";
  3759 
  3760 * Pure: new 'judgment' command records explicit information about the
  3761 object-logic embedding (used by several tools internally); no longer
  3762 use hard-wired "Trueprop";
  3763 
  3764 * Pure: added 'corollary' command;
  3765 
  3766 * Pure: fixed 'token_translation' command;
  3767 
  3768 * Pure: removed obsolete 'exported' attribute;
  3769 
  3770 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3771 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3772 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3773 
  3774 * Pure: method 'atomize' presents local goal premises as object-level
  3775 statements (atomic meta-level propositions); setup controlled via
  3776 rewrite rules declarations of 'atomize' attribute; example
  3777 application: 'induct' method with proper rule statements in improper
  3778 proof *scripts*;
  3779 
  3780 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3781 now consider the syntactic context of assumptions, giving a better
  3782 chance to get type-inference of the arguments right (this is
  3783 especially important for locales);
  3784 
  3785 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3786 mode;
  3787 
  3788 * Pure/obtain: the formal conclusion "thesis", being marked as
  3789 ``internal'', may no longer be reference directly in the text;
  3790 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3791 situations;
  3792 
  3793 * Pure: generic 'sym' attribute which declares a rule both as pure
  3794 'elim?' and for the 'symmetric' operation;
  3795 
  3796 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3797 text; the fixed correlation with particular command syntax has been
  3798 discontinued;
  3799 
  3800 * Pure: new method 'rules' is particularly well-suited for proof
  3801 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3802 but often produces more compact proof terms with less detours;
  3803 
  3804 * Pure/Provers/classical: simplified integration with pure rule
  3805 attributes and methods; the classical "intro?/elim?/dest?"
  3806 declarations coincide with the pure ones; the "rule" method no longer
  3807 includes classically swapped intros; "intro" and "elim" methods no
  3808 longer pick rules from the context; also got rid of ML declarations
  3809 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3810 INCOMPATIBILITY;
  3811 
  3812 * Provers/classical: attribute 'swapped' produces classical inversions
  3813 of introduction rules;
  3814 
  3815 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3816 rules instead of full simplifier context; 'iff' attribute handles
  3817 conditional rules;
  3818 
  3819 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3820 
  3821 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3822 "(permissive)" option to recover old behavior;
  3823 
  3824 * HOL: 'inductive' no longer features separate (collective) attributes
  3825 for 'intros' (was found too confusing);
  3826 
  3827 * HOL: properly declared induction rules less_induct and
  3828 wf_induct_rule;
  3829 
  3830 
  3831 *** HOL ***
  3832 
  3833 * HOL: moved over to sane numeral syntax; the new policy is as
  3834 follows:
  3835 
  3836   - 0 and 1 are polymorphic constants, which are defined on any
  3837   numeric type (nat, int, real etc.);
  3838 
  3839   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3840   binary representation internally;
  3841 
  3842   - type nat has special constructor Suc, and generally prefers Suc 0
  3843   over 1::nat and Suc (Suc 0) over 2::nat;
  3844 
  3845 This change may cause significant problems of INCOMPATIBILITY; here
  3846 are some hints on converting existing sources:
  3847 
  3848   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3849   entities, so expressions involving "-" (unary or binary minus) need
  3850   to be spaced properly;
  3851 
  3852   - existing occurrences of "1" may need to be constraint "1::nat" or
  3853   even replaced by Suc 0; similar for old "2";
  3854 
  3855   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3856 
  3857   - remove all special provisions on numerals in proofs;
  3858 
  3859 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3860 representation (depends on bin_arith_simps in the default context);
  3861 
  3862 * HOL: symbolic syntax for x^2 (numeral 2);
  3863 
  3864 * HOL: the class of all HOL types is now called "type" rather than
  3865 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3866 in axclass/classes, instance/arities, and (usually rare) occurrences
  3867 in typings (of consts etc.); internally the class is called
  3868 "HOL.type", ML programs should refer to HOLogic.typeS;
  3869 
  3870 * HOL/record package improvements:
  3871   - new derived operations "fields" to build a partial record section,
  3872     "extend" to promote a fixed record to a record scheme, and
  3873     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3874     declared as simp by default;
  3875   - shared operations ("more", "fields", etc.) now need to be always
  3876     qualified) --- potential INCOMPATIBILITY;
  3877   - removed "make_scheme" operations (use "make" with "extend") --
  3878     INCOMPATIBILITY;
  3879   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3880   - provides cases/induct rules for use with corresponding Isar
  3881     methods (for concrete records, record schemes, concrete more
  3882     parts, and schematic more parts -- in that order);
  3883   - internal definitions directly based on a light-weight abstract
  3884     theory of product types over typedef rather than datatype;
  3885 
  3886 * HOL: generic code generator for generating executable ML code from
  3887 specifications; specific support for HOL constructs such as inductive
  3888 datatypes and sets, as well as recursive functions; can be invoked
  3889 via 'generate_code' theory section;
  3890 
  3891 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3892 
  3893 * HOL: consolidated and renamed several theories.  In particular:
  3894         Ord.thy has been absorbed into HOL.thy
  3895         String.thy has been absorbed into List.thy
  3896 
  3897 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3898 (beware of argument permutation!);
  3899 
  3900 * HOL: linorder_less_split superseded by linorder_cases;
  3901 
  3902 * HOL/List: "nodups" renamed to "distinct";
  3903 
  3904 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3905 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3906   - Ex_def has changed, now need to use some_eq_ex
  3907 
  3908 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3909 in this (rare) case use:
  3910 
  3911   delSWrapper "split_all_tac"
  3912   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3913 
  3914 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3915 MAY FAIL;
  3916 
  3917 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3918 Isabelle's type classes, ^ on functions and relations has too general
  3919 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3920 necessary to attach explicit type constraints;
  3921 
  3922 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3923 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3924 renamed accordingly (eg "compI" -> "rel_compI").
  3925 
  3926 * HOL: syntax translations now work properly with numerals and records
  3927 expressions;
  3928 
  3929 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3930 of "lam" -- INCOMPATIBILITY;
  3931 
  3932 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3933 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3934 renamed "Product_Type.unit";
  3935 
  3936 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3937 
  3938 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3939 the "cases" method);
  3940 
  3941 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3942 Florian Kammller);
  3943 
  3944 * HOL/IMP: updated and converted to new-style theory format; several
  3945 parts turned into readable document, with proper Isar proof texts and
  3946 some explanations (by Gerwin Klein);
  3947 
  3948 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3949 
  3950 * HOL-Hyperreal is now a logic image;
  3951 
  3952 
  3953 *** HOLCF ***
  3954 
  3955 * Isar: consts/constdefs supports mixfix syntax for continuous
  3956 operations;
  3957 
  3958 * Isar: domain package adapted to new-style theory format, e.g. see
  3959 HOLCF/ex/Dnat.thy;
  3960 
  3961 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3962 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3963 lift.induct_tac, always use UU instead of Undef;
  3964 
  3965 * HOLCF/IMP: updated and converted to new-style theory;
  3966 
  3967 
  3968 *** ZF ***
  3969 
  3970 * Isar: proper integration of logic-specific tools and packages,
  3971 including theory commands '(co)inductive', '(co)datatype',
  3972 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3973 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3974 
  3975 * theory Main no longer includes AC; for the Axiom of Choice, base
  3976 your theory on Main_ZFC;
  3977 
  3978 * the integer library now covers quotients and remainders, with many
  3979 laws relating division to addition, multiplication, etc.;
  3980 
  3981 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3982 typeless version of the formalism;
  3983 
  3984 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3985 format;
  3986 
  3987 * ZF/Induct: new directory for examples of inductive definitions,
  3988 including theory Multiset for multiset orderings; converted to
  3989 new-style theory format;
  3990 
  3991 * ZF: many new theorems about lists, ordinals, etc.;
  3992 
  3993 
  3994 *** General ***
  3995 
  3996 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3997 variable proof controls level of detail: 0 = no proofs (only oracle
  3998 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3999 also ref manual for further ML interfaces;
  4000 
  4001 * Pure/axclass: removed obsolete ML interface
  4002 goal_subclass/goal_arity;
  4003 
  4004 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4005 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4006 separate tokens, so expressions involving minus need to be spaced
  4007 properly;
  4008 
  4009 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4010 rather than "infixl" or "infixr";
  4011 
  4012 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4013 sort constraint specifications in type inference; e.g. "x::_::foo"
  4014 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4015 type variable);
  4016 
  4017 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4018 control output of nested => (types); the default behavior is
  4019 "type_brackets";
  4020 
  4021 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4022 tokens into AST constants;
  4023 
  4024 * Pure/syntax: prefer later declarations of translations and print
  4025 translation functions; potential INCOMPATIBILITY: need to reverse
  4026 multiple declarations for same syntax element constant;
  4027 
  4028 * Pure/show_hyps reset by default (in accordance to existing Isar
  4029 practice);
  4030 
  4031 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4032 addSafter;
  4033 
  4034 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4035 as well;
  4036 
  4037 * system: tested support for MacOS X; should be able to get Isabelle +
  4038 Proof General to work in a plain Terminal after installing Poly/ML
  4039 (e.g. from the Isabelle distribution area) and GNU bash alone
  4040 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4041 support requires further installations, e.g. from
  4042 http://fink.sourceforge.net/);
  4043 
  4044 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4045 
  4046 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4047 of 40 MB), cf. ML_OPTIONS;
  4048 
  4049 * system: Proof General keywords specification is now part of the
  4050 Isabelle distribution (see etc/isar-keywords.el);
  4051 
  4052 * system: support for persistent Proof General sessions (refrain from
  4053 outdating all loaded theories on startup); user may create writable
  4054 logic images like this: ``isabelle -q HOL Test'';
  4055 
  4056 * system: smart selection of Isabelle process versus Isabelle
  4057 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4058 run both "isabelle" and "Isabelle" even if file names are badly
  4059 damaged (executable inspects the case of the first letter of its own
  4060 name); added separate "isabelle-process" and "isabelle-interface";
  4061 
  4062 * system: refrain from any attempt at filtering input streams; no
  4063 longer support ``8bit'' encoding of old isabelle font, instead proper
  4064 iso-latin characters may now be used; the related isatools
  4065 "symbolinput" and "nonascii" have disappeared as well;
  4066 
  4067 * system: removed old "xterm" interface (the print modes "xterm" and
  4068 "xterm_color" are still available for direct use in a suitable
  4069 terminal);
  4070 
  4071 
  4072 
  4073 New in Isabelle99-2 (February 2001)
  4074 -----------------------------------
  4075 
  4076 *** Overview of INCOMPATIBILITIES ***
  4077 
  4078 * HOL: please note that theories in the Library and elsewhere often use the
  4079 new-style (Isar) format; to refer to their theorems in an ML script you must
  4080 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4081 
  4082 * HOL: inductive package no longer splits induction rule aggressively,
  4083 but only as far as specified by the introductions given; the old
  4084 format may be recovered via ML function complete_split_rule or attribute
  4085 'split_rule (complete)';
  4086 
  4087 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4088 gfp_Tarski to gfp_unfold;
  4089 
  4090 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4091 
  4092 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4093 relation); infix "^^" has been renamed "``"; infix "``" has been
  4094 renamed "`"; "univalent" has been renamed "single_valued";
  4095 
  4096 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4097 operation;
  4098 
  4099 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4100 
  4101 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4102 
  4103 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4104 consequence, it is no longer monotonic wrt. the local goal context
  4105 (which is now passed through the inductive cases);
  4106 
  4107 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4108 \<gg> to \<ggreater>;
  4109 
  4110 
  4111 *** Document preparation ***
  4112 
  4113 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4114 available: are "it" for near math-mode best-style output, "sl" for
  4115 slanted text style, and "tt" for plain type-writer; if no
  4116 \isabellestyle command is given, output is according to slanted
  4117 type-writer);
  4118 
  4119 * support sub/super scripts (for single symbols only), input syntax is
  4120 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4121 
  4122 * some more standard symbols; see Appendix A of the system manual for
  4123 the complete list of symbols defined in isabellesym.sty;
  4124 
  4125 * improved isabelle style files; more abstract symbol implementation
  4126 (should now use \isamath{...} and \isatext{...} in custom symbol
  4127 definitions);
  4128 
  4129 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4130 state; Note that presentation of goal states does not conform to
  4131 actual human-readable proof documents.  Please do not include goal
  4132 states into document output unless you really know what you are doing!
  4133 
  4134 * proper indentation of antiquoted output with proportional LaTeX
  4135 fonts;
  4136 
  4137 * no_document ML operator temporarily disables LaTeX document
  4138 generation;
  4139 
  4140 * isatool unsymbolize tunes sources for plain ASCII communication;
  4141 
  4142 
  4143 *** Isar ***
  4144 
  4145 * Pure: Isar now suffers initial goal statements to contain unbound
  4146 schematic variables (this does not conform to actual readable proof
  4147 documents, due to unpredictable outcome and non-compositional proof
  4148 checking); users who know what they are doing may use schematic goals
  4149 for Prolog-style synthesis of proven results;
  4150 
  4151 * Pure: assumption method (an implicit finishing) now handles actual
  4152 rules as well;
  4153 
  4154 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4155 initial goal, declare "that" only as Pure intro (only for single
  4156 steps); the "that" rule assumption may now be involved in implicit
  4157 finishing, thus ".." becomes a feasible for trivial obtains;
  4158 
  4159 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4160 instance proofs may be performed by "..";
  4161 
  4162 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4163 statements as well;
  4164 
  4165 * Pure: more robust selection of calculational rules;
  4166 
  4167 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4168 rule (as well as the assumption rule);
  4169 
  4170 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4171 lemmas, using the graph browser tool;
  4172 
  4173 * Pure: predict failure of "show" in interactive mode;
  4174 
  4175 * Pure: 'thms_containing' now takes actual terms as arguments;
  4176 
  4177 * HOL: improved method 'induct' --- now handles non-atomic goals
  4178 (potential INCOMPATIBILITY); tuned error handling;
  4179 
  4180 * HOL: cases and induct rules now provide explicit hints about the
  4181 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4182 any remaining facts are inserted into the goal verbatim;
  4183 
  4184 * HOL: local contexts (aka cases) may now contain term bindings as
  4185 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4186 the result to be shown in each case;
  4187 
  4188 * HOL: added 'recdef_tc' command;
  4189 
  4190 * isatool convert assists in eliminating legacy ML scripts;
  4191 
  4192 
  4193 *** HOL ***
  4194 
  4195 * HOL/Library: a collection of generic theories to be used together
  4196 with main HOL; the theory loader path already includes this directory
  4197 by default; the following existing theories have been moved here:
  4198 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4199 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4200 
  4201 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4202 modelling and verification task performed in Isabelle/HOL +
  4203 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4204 
  4205 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4206 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4207 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4208 'domain', this makes the theory consistent with mathematical
  4209 literature;
  4210 
  4211 * HOL basics: added overloaded operations "inverse" and "divide"
  4212 (infix "/"), syntax for generic "abs" operation, generic summation
  4213 operator \<Sum>;
  4214 
  4215 * HOL/typedef: simplified package, provide more useful rules (see also
  4216 HOL/subset.thy);
  4217 
  4218 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4219 now expressed as a proper nested rule (old-style tactic scripts may
  4220 require atomize_strip_tac to cope with non-atomic premises);
  4221 
  4222 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4223 to "split_conv" (old name still available for compatibility);
  4224 
  4225 * HOL: improved concrete syntax for strings (e.g. allows translation
  4226 rules with string literals);
  4227 
  4228 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4229  and Fleuriot's mechanization of analysis, including the transcendental
  4230  functions for the reals;
  4231 
  4232 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4233 
  4234 
  4235 *** CTT ***
  4236 
  4237 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4238 "lam" is displayed as TWO lambda-symbols
  4239 
  4240 * CTT: theory Main now available, containing everything (that is, Bool
  4241 and Arith);
  4242 
  4243 
  4244 *** General ***
  4245 
  4246 * Pure: the Simplifier has been implemented properly as a derived rule
  4247 outside of the actual kernel (at last!); the overall performance
  4248 penalty in practical applications is about 50%, while reliability of
  4249 the Isabelle inference kernel has been greatly improved;
  4250 
  4251 * print modes "brackets" and "no_brackets" control output of nested =>
  4252 (types) and ==> (props); the default behaviour is "brackets";
  4253 
  4254 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4255 as assumptions as well;
  4256 
  4257 * system: support Poly/ML 4.0;
  4258 
  4259 * system: isatool install handles KDE version 1 or 2;
  4260 
  4261 
  4262 
  4263 New in Isabelle99-1 (October 2000)
  4264 ----------------------------------
  4265 
  4266 *** Overview of INCOMPATIBILITIES ***
  4267 
  4268 * HOL: simplification of natural numbers is much changed; to partly
  4269 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4270 issue the following ML commands:
  4271 
  4272   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4273   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4274 
  4275 * HOL: simplification no longer dives into case-expressions; this is
  4276 controlled by "t.weak_case_cong" for each datatype t;
  4277 
  4278 * HOL: nat_less_induct renamed to less_induct;
  4279 
  4280 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4281 fixsome to patch .thy and .ML sources automatically;
  4282 
  4283   select_equality  -> some_equality
  4284   select_eq_Ex     -> some_eq_ex
  4285   selectI2EX       -> someI2_ex
  4286   selectI2         -> someI2
  4287   selectI          -> someI
  4288   select1_equality -> some1_equality
  4289   Eps_sym_eq       -> some_sym_eq_trivial
  4290   Eps_eq           -> some_eq_trivial
  4291 
  4292 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4293 
  4294 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4295 instead);
  4296 
  4297 * HOL: the recursion equations generated by 'recdef' are now called
  4298 f.simps instead of f.rules;
  4299 
  4300 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4301 
  4302 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4303 sometimes be needed;
  4304 
  4305 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4306 
  4307 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4308 
  4309 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4310 product is now "<*>" instead of "Times"; the lexicographic product is
  4311 now "<*lex*>" instead of "**";
  4312 
  4313 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4314 of main HOL, but was unused); better use HOL's datatype package;
  4315 
  4316 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4317 the old syntax may be recovered as follows:
  4318 
  4319   syntax (symbols)
  4320     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4321       (infixl "\\<oplus>" 100)
  4322 
  4323 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4324 
  4325 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4326 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4327 internally;
  4328 
  4329 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4330 changed from A/r to A//r;
  4331 
  4332 * ZF: new treatment of arithmetic (nat & int) may break some old
  4333 proofs;
  4334 
  4335 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4336 rulify -> rule_format, elimify -> elim_format, ...);
  4337 
  4338 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4339 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4340 should have to change intro!! to intro? only); replaced "delrule" by
  4341 "rule del";
  4342 
  4343 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4344 
  4345 * Provers: strengthened force_tac by using new first_best_tac;
  4346 
  4347 * LaTeX document preparation: several changes of isabelle.sty (see
  4348 lib/texinputs);
  4349 
  4350 
  4351 *** Document preparation ***
  4352 
  4353 * formal comments (text blocks etc.) in new-style theories may now
  4354 contain antiquotations of thm/prop/term/typ/text to be presented
  4355 according to latex print mode; concrete syntax is like this:
  4356 @{term[show_types] "f(x) = a + x"};
  4357 
  4358 * isatool mkdir provides easy setup of Isabelle session directories,
  4359 including proper document sources;
  4360 
  4361 * generated LaTeX sources are now deleted after successful run
  4362 (isatool document -c); may retain a copy somewhere else via -D option
  4363 of isatool usedir;
  4364 
  4365 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4366 style files, achieving self-contained LaTeX sources and simplifying
  4367 LaTeX debugging;
  4368 
  4369 * old-style theories now produce (crude) LaTeX output as well;
  4370 
  4371 * browser info session directories are now self-contained (may be put
  4372 on WWW server seperately); improved graphs of nested sessions; removed
  4373 graph for 'all sessions';
  4374 
  4375 * several improvements in isabelle style files; \isabellestyle{it}
  4376 produces fake math mode output; \isamarkupheader is now \section by
  4377 default; see lib/texinputs/isabelle.sty etc.;
  4378 
  4379 
  4380 *** Isar ***
  4381 
  4382 * Isar/Pure: local results and corresponding term bindings are now
  4383 subject to Hindley-Milner polymorphism (similar to ML); this
  4384 accommodates incremental type-inference very nicely;
  4385 
  4386 * Isar/Pure: new derived language element 'obtain' supports
  4387 generalized existence reasoning;
  4388 
  4389 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4390 support accumulation of results, without applying any rules yet;
  4391 useful to collect intermediate results without explicit name
  4392 references, and for use with transitivity rules with more than 2
  4393 premises;
  4394 
  4395 * Isar/Pure: scalable support for case-analysis type proofs: new
  4396 'case' language element refers to local contexts symbolically, as
  4397 produced by certain proof methods; internally, case names are attached
  4398 to theorems as "tags";
  4399 
  4400 * Isar/Pure: theory command 'hide' removes declarations from
  4401 class/type/const name spaces;
  4402 
  4403 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4404 indicate potential overloading;
  4405 
  4406 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4407 
  4408 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4409 "{a,b,c}" instead of {a,b,c};
  4410 
  4411 * Isar/Pure now provides its own version of intro/elim/dest
  4412 attributes; useful for building new logics, but beware of confusion
  4413 with the version in Provers/classical;
  4414 
  4415 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4416 case name 'antecedent';
  4417 
  4418 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4419 to the current context is now done automatically);
  4420 
  4421 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4422 for definining proof methods in ML;
  4423 
  4424 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4425 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4426 most cases, one should have to change intro!! to intro? only);
  4427 replaced "delrule" by "rule del";
  4428 
  4429 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4430 'symmetric' attribute (the latter supercedes [RS sym]);
  4431 
  4432 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4433 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4434 well (including splits);
  4435 
  4436 * Isar/Provers: Simplifier and Classical methods now support all kind
  4437 of modifiers used in the past, including 'cong', 'iff', etc.
  4438 
  4439 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4440 of Simplifier and Classical reasoner);
  4441 
  4442 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4443 now support named cases; major packages (inductive, datatype, primrec,
  4444 recdef) support case names and properly name parameters;
  4445 
  4446 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4447 monotonicity conditions are extracted to be proven at end of
  4448 calculations;
  4449 
  4450 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4451 method anyway;
  4452 
  4453 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4454 split_if split_if_asm; datatype package provides theorems foo.splits =
  4455 foo.split foo.split_asm for each datatype;
  4456 
  4457 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4458 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4459 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4460 use "(cases (simplified))" method in proper proof texts);
  4461 
  4462 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4463 
  4464 * Isar: names of theorems etc. may be natural numbers as well;
  4465 
  4466 * Isar: 'pr' command: optional arguments for goals_limit and
  4467 ProofContext.prems_limit; no longer prints theory contexts, but only
  4468 proof states;
  4469 
  4470 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4471 additional print modes to be specified; e.g. "pr(latex)" will print
  4472 proof state according to the Isabelle LaTeX style;
  4473 
  4474 * Isar: improved support for emulating tactic scripts, including proof
  4475 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4476 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4477 (for HOL datatypes);
  4478 
  4479 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4480 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4481 'proof method scripts' have to be in depth-first order;
  4482 
  4483 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4484 
  4485 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4486 should instead use individual commands for printing items
  4487 (print_commands, print_methods etc.);
  4488 
  4489 * Isar: added 'nothing' --- the empty list of theorems;
  4490 
  4491 
  4492 *** HOL ***
  4493 
  4494 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4495 corresponding virtual machine and a specification of its bytecode
  4496 verifier and a lightweight bytecode verifier, including proofs of
  4497 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4498 Cornelia Pusch (see also the homepage of project Bali at
  4499 http://isabelle.in.tum.de/Bali/);
  4500 
  4501 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4502 Clemens Ballarin;
  4503 
  4504 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4505 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4506 Rasmussen;
  4507 
  4508 * HOL/Lattice: fundamental concepts of lattice theory and order
  4509 structures, including duals, properties of bounds versus algebraic
  4510 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4511 Theorem for complete lattices etc.; may also serve as a demonstration
  4512 for abstract algebraic reasoning using axiomatic type classes, and
  4513 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4514 
  4515 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4516 von Oheimb;
  4517 
  4518 * HOL/IMPP: extension of IMP with local variables and mutually
  4519 recursive procedures, by David von Oheimb;
  4520 
  4521 * HOL/Lambda: converted into new-style theory and document;
  4522 
  4523 * HOL/ex/Multiquote: example of multiple nested quotations and
  4524 anti-quotations -- basically a generalized version of de-Bruijn
  4525 representation; very useful in avoiding lifting of operations;
  4526 
  4527 * HOL/record: added general record equality rule to simpset; fixed
  4528 select-update simplification procedure to handle extended records as
  4529 well; admit "r" as field name;
  4530 
  4531 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4532 other numeric types and also as the identity of groups, rings, etc.;
  4533 
  4534 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4535 Types nat and int belong to this axclass;
  4536 
  4537 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4538    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4539    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4540   two terms #m*u and #n*u are replaced by #(m+n)*u
  4541     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4542   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4543     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4544 
  4545 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4546 powerful prover for predicate logic but knows nothing of clasets; see
  4547 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4548 
  4549 * HOL: new version of "case_tac" subsumes both boolean case split and
  4550 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4551 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4552 
  4553 * HOL: simplification no longer dives into case-expressions: only the
  4554 selector expression is simplified, but not the remaining arms; to
  4555 enable full simplification of case-expressions for datatype t, you may
  4556 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4557 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4558 
  4559 * HOL/recdef: the recursion equations generated by 'recdef' for
  4560 function 'f' are now called f.simps instead of f.rules; if all
  4561 termination conditions are proved automatically, these simplification
  4562 rules are added to the simpset, as in primrec; rules may be named
  4563 individually as well, resulting in a separate list of theorems for
  4564 each equation;
  4565 
  4566 * HOL/While is a new theory that provides a while-combinator. It
  4567 permits the definition of tail-recursive functions without the
  4568 provision of a termination measure. The latter is necessary once the
  4569 invariant proof rule for while is applied.
  4570 
  4571 * HOL: new (overloaded) notation for the set of elements below/above
  4572 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4573 
  4574 * HOL: theorems impI, allI, ballI bound as "strip";
  4575 
  4576 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4577 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4578 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4579 
  4580 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4581 
  4582 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4583 main HOL, but was unused);
  4584 
  4585 * HOL: fewer consts declared as global (e.g. have to refer to
  4586 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4587 
  4588 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4589 in case of overlap with user translations (e.g. judgements over
  4590 tuples); (note that the underlying logical represenation is still
  4591 bogus);
  4592 
  4593 
  4594 *** ZF ***
  4595 
  4596 * ZF: simplification automatically cancels common terms in arithmetic
  4597 expressions over nat and int;
  4598 
  4599 * ZF: new treatment of nat to minimize type-checking: all operators
  4600 coerce their operands to a natural number using the function natify,
  4601 making the algebraic laws unconditional;
  4602 
  4603 * ZF: as above, for int: operators coerce their operands to an integer
  4604 using the function intify;
  4605 
  4606 * ZF: the integer library now contains many of the usual laws for the
  4607 orderings, including $<=, and monotonicity laws for $+ and $*;
  4608 
  4609 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4610 simplification;
  4611 
  4612 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4613 to the simplifier and classical reasoner simultaneously;
  4614 
  4615 
  4616 *** General ***
  4617 
  4618 * Provers: blast_tac now handles actual object-logic rules as
  4619 assumptions; note that auto_tac uses blast_tac internally as well;
  4620 
  4621 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4622 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4623 
  4624 * Provers: delrules now handles destruct rules as well (no longer need
  4625 explicit make_elim);
  4626 
  4627 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4628   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4629 use instead the strong form,
  4630   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4631 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4632 from destruct-rules;
  4633 
  4634 * Provers: Simplifier.easy_setup provides a fast path to basic
  4635 Simplifier setup for new object-logics;
  4636 
  4637 * Pure: AST translation rules no longer require constant head on LHS;
  4638 
  4639 * Pure: improved name spaces: ambiguous output is qualified; support
  4640 for hiding of names;
  4641 
  4642 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4643 XSYMBOL_HOME; no longer need to do manual configuration in most
  4644 situations;
  4645 
  4646 * system: compression of ML heaps images may now be controlled via -c
  4647 option of isabelle and isatool usedir (currently only observed by
  4648 Poly/ML);
  4649 
  4650 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4651 useful for remote X11);
  4652 
  4653 * system: provide TAGS file for Isabelle sources;
  4654 
  4655 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4656 order;
  4657 
  4658 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4659 timing flag supersedes proof_timing and Toplevel.trace;
  4660 
  4661 * ML: new combinators |>> and |>>> for incremental transformations
  4662 with secondary results (e.g. certain theory extensions):
  4663 
  4664 * ML: PureThy.add_defs gets additional argument to indicate potential
  4665 overloading (usually false);
  4666 
  4667 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4668 results;
  4669 
  4670 
  4671 
  4672 New in Isabelle99 (October 1999)
  4673 --------------------------------
  4674 
  4675 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4676 
  4677 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4678 are no longer simplified.  (This allows the simplifier to unfold recursive
  4679 functional programs.)  To restore the old behaviour, declare
  4680 
  4681     Delcongs [if_weak_cong];
  4682 
  4683 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4684 complement;
  4685 
  4686 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4687 
  4688 * HOL/datatype: mutual_induct_tac no longer exists --
  4689   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  4690 
  4691 * HOL/typedef: fixed type inference for representing set; type
  4692 arguments now have to occur explicitly on the rhs as type constraints;
  4693 
  4694 * ZF: The con_defs part of an inductive definition may no longer refer
  4695 to constants declared in the same theory;
  4696 
  4697 * HOL, ZF: the function mk_cases, generated by the inductive
  4698 definition package, has lost an argument.  To simplify its result, it
  4699 uses the default simpset instead of a supplied list of theorems.
  4700 
  4701 * HOL/List: the constructors of type list are now Nil and Cons;
  4702 
  4703 * Simplifier: the type of the infix ML functions
  4704         setSSolver addSSolver setSolver addSolver
  4705 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4706 for packaging solvers. A solver is created via
  4707         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4708 where the string argument is only a comment.
  4709 
  4710 
  4711 *** Proof tools ***
  4712 
  4713 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4714 decision procedure for linear arithmetic. Currently it is used for
  4715 types `nat', `int', and `real' in HOL (see below); it can, should and
  4716 will be instantiated for other types and logics as well.
  4717 
  4718 * The simplifier now accepts rewrite rules with flexible heads, eg
  4719      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4720   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4721   matching.
  4722 
  4723 
  4724 *** General ***
  4725 
  4726 * New Isabelle/Isar subsystem provides an alternative to traditional
  4727 tactical theorem proving; together with the ProofGeneral/isar user
  4728 interface it offers an interactive environment for developing human
  4729 readable proof documents (Isar == Intelligible semi-automated
  4730 reasoning); for further information see isatool doc isar-ref,
  4731 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  4732 
  4733 * improved and simplified presentation of theories: better HTML markup
  4734 (including colors), graph views in several sizes; isatool usedir now
  4735 provides a proper interface for user theories (via -P option); actual
  4736 document preparation based on (PDF)LaTeX is available as well (for
  4737 new-style theories only); see isatool doc system for more information;
  4738 
  4739 * native support for Proof General, both for classic Isabelle and
  4740 Isabelle/Isar;
  4741 
  4742 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  4743 using the graph browser tool;
  4744 
  4745 * Isabelle manuals now also available as PDF;
  4746 
  4747 * theory loader rewritten from scratch (may not be fully
  4748 bug-compatible); old loadpath variable has been replaced by show_path,
  4749 add_path, del_path, reset_path functions; new operations such as
  4750 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  4751 isatool doc ref);
  4752 
  4753 * improved isatool install: option -k creates KDE application icon,
  4754 option -p DIR installs standalone binaries;
  4755 
  4756 * added ML_PLATFORM setting (useful for cross-platform installations);
  4757 more robust handling of platform specific ML images for SML/NJ;
  4758 
  4759 * the settings environment is now statically scoped, i.e. it is never
  4760 created again in sub-processes invoked from isabelle, isatool, or
  4761 Isabelle;
  4762 
  4763 * path element specification '~~' refers to '$ISABELLE_HOME';
  4764 
  4765 * in locales, the "assumes" and "defines" parts may be omitted if
  4766 empty;
  4767 
  4768 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4769 long arrows);
  4770 
  4771 * new print_mode "HTML";
  4772 
  4773 * new flag show_tags controls display of tags of theorems (which are
  4774 basically just comments that may be attached by some tools);
  4775 
  4776 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4777 mode and goal output format:
  4778 
  4779 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4780 244c244
  4781 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4782 ---
  4783 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4784 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4785 181c181
  4786 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4787 ---
  4788 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4789 
  4790 * function bind_thms stores lists of theorems (cf. bind_thm);
  4791 
  4792 * new shorthand tactics ftac, eatac, datac, fatac;
  4793 
  4794 * qed (and friends) now accept "" as result name; in that case the
  4795 theorem is not stored, but proper checks and presentation of the
  4796 result still apply;
  4797 
  4798 * theorem database now also indexes constants "Trueprop", "all",
  4799 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4800 
  4801 
  4802 *** HOL ***
  4803 
  4804 ** HOL arithmetic **
  4805 
  4806 * There are now decision procedures for linear arithmetic over nat and
  4807 int:
  4808 
  4809 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4810 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4811 are treated as atomic; subformulae not involving type `nat' or `int'
  4812 are ignored; quantified subformulae are ignored unless they are
  4813 positive universal or negative existential. The tactic has to be
  4814 invoked by hand and can be a little bit slow. In particular, the
  4815 running time is exponential in the number of occurrences of `min' and
  4816 `max', and `-' on `nat'.
  4817 
  4818 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4819 (negated) (in)equalities among the premises and the conclusion into
  4820 account (i.e. no compound formulae) and does not know about `min' and
  4821 `max', and `-' on `nat'. It is fast and is used automatically by the
  4822 simplifier.
  4823 
  4824 NB: At the moment, these decision procedures do not cope with mixed
  4825 nat/int formulae where the two parts interact, such as `m < n ==>
  4826 int(m) < int(n)'.
  4827 
  4828 * HOL/Numeral provides a generic theory of numerals (encoded
  4829 efficiently as bit strings); setup for types nat/int/real is in place;
  4830 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4831 int, existing theories and proof scripts may require a few additional
  4832 type constraints;
  4833 
  4834 * integer division and remainder can now be performed on constant
  4835 arguments;
  4836 
  4837 * many properties of integer multiplication, division and remainder
  4838 are now available;
  4839 
  4840 * An interface to the Stanford Validity Checker (SVC) is available through the
  4841 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4842 are proved automatically.  SVC must be installed separately, and its results
  4843 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4844 invocation of the underlying oracle).  For SVC see
  4845   http://verify.stanford.edu/SVC
  4846 
  4847 * IsaMakefile: the HOL-Real target now builds an actual image;
  4848 
  4849 
  4850 ** HOL misc **
  4851 
  4852 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4853 (in Isabelle/Isar) -- by Gertrud Bauer;
  4854 
  4855 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4856 analysis for assembly languages with subtypes;
  4857 
  4858 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4859 -- avoids syntactic ambiguities and treats state, transition, and
  4860 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4861 changed syntax and (many) tactics;
  4862 
  4863 * HOL/inductive: Now also handles more general introduction rules such
  4864   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4865   theorems are now maintained within the theory (maintained via the
  4866   "mono" attribute);
  4867 
  4868 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4869   (using function types) such as
  4870 
  4871   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4872 
  4873 * HOL/record: record_simproc (part of the default simpset) takes care
  4874 of selectors applied to updated records; record_split_tac is no longer
  4875 part of the default claset; update_defs may now be removed from the
  4876 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4877 
  4878   claset_ref () := claset() addSWrapper record_split_wrapper;
  4879   Delsimprocs [record_simproc]
  4880 
  4881 * HOL/typedef: fixed type inference for representing set; type
  4882 arguments now have to occur explicitly on the rhs as type constraints;
  4883 
  4884 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4885 names rather than an ML expression;
  4886 
  4887 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4888 supplied later.  Program schemes can be defined, such as
  4889     "While B C s = (if B s then While B C (C s) else s)"
  4890 where the well-founded relation can be chosen after B and C have been given.
  4891 
  4892 * HOL/List: the constructors of type list are now Nil and Cons;
  4893 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4894 course, ML tools referring to List.list.op # etc. have to be adapted;
  4895 
  4896 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4897 disabled by default; run isabelle with option -m HOL to get back to
  4898 the original Gordon/HOL-style output;
  4899 
  4900 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4901 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4902 
  4903 * HOL basic syntax simplified (more orthogonal): all variants of
  4904 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4905 Eps operator is provided as well: "SOME x. P[x]";
  4906 
  4907 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4908 
  4909 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4910 thus available for user theories;
  4911 
  4912 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4913 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4914 time;
  4915 
  4916 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4917 several times and then mp;
  4918 
  4919 
  4920 *** LK ***
  4921 
  4922 * the notation <<...>> is now available as a notation for sequences of
  4923 formulas;
  4924 
  4925 * the simplifier is now installed
  4926 
  4927 * the axiom system has been generalized (thanks to Soren Heilmann)
  4928 
  4929 * the classical reasoner now has a default rule database
  4930 
  4931 
  4932 *** ZF ***
  4933 
  4934 * new primrec section allows primitive recursive functions to be given
  4935 directly (as in HOL) over datatypes and the natural numbers;
  4936 
  4937 * new tactics induct_tac and exhaust_tac for induction (or case
  4938 analysis) over datatypes and the natural numbers;
  4939 
  4940 * the datatype declaration of type T now defines the recursor T_rec;
  4941 
  4942 * simplification automatically does freeness reasoning for datatype
  4943 constructors;
  4944 
  4945 * automatic type-inference, with AddTCs command to insert new
  4946 type-checking rules;
  4947 
  4948 * datatype introduction rules are now added as Safe Introduction rules
  4949 to the claset;
  4950 
  4951 * the syntax "if P then x else y" is now available in addition to
  4952 if(P,x,y);
  4953 
  4954 
  4955 *** Internal programming interfaces ***
  4956 
  4957 * tuned simplifier trace output; new flag debug_simp;
  4958 
  4959 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4960 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4961 
  4962 * AxClass.axclass_tac lost the theory argument;
  4963 
  4964 * tuned current_goals_markers semantics: begin / end goal avoids
  4965 printing empty lines;
  4966 
  4967 * removed prs and prs_fn hook, which was broken because it did not
  4968 include \n in its semantics, forcing writeln to add one
  4969 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4970 string -> unit if you really want to output text without newline;
  4971 
  4972 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4973 plain output, interface builders may have to enable 'isabelle_font'
  4974 mode to get Isabelle font glyphs as before;
  4975 
  4976 * refined token_translation interface; INCOMPATIBILITY: output length
  4977 now of type real instead of int;
  4978 
  4979 * theory loader actions may be traced via new ThyInfo.add_hook
  4980 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4981 your own database of information attached to *whole* theories -- as
  4982 opposed to intra-theory data slots offered via TheoryDataFun;
  4983 
  4984 * proper handling of dangling sort hypotheses (at last!);
  4985 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4986 extra sort hypotheses that can be witnessed from the type signature;
  4987 the force_strip_shyps flag is gone, any remaining shyps are simply
  4988 left in the theorem (with a warning issued by strip_shyps_warning);
  4989 
  4990 
  4991 
  4992 New in Isabelle98-1 (October 1998)
  4993 ----------------------------------
  4994 
  4995 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4996 
  4997 * several changes of automated proof tools;
  4998 
  4999 * HOL: major changes to the inductive and datatype packages, including
  5000 some minor incompatibilities of theory syntax;
  5001 
  5002 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5003 called `inj_on';
  5004 
  5005 * HOL: removed duplicate thms in Arith:
  5006   less_imp_add_less  should be replaced by  trans_less_add1
  5007   le_imp_add_le      should be replaced by  trans_le_add1
  5008 
  5009 * HOL: unary minus is now overloaded (new type constraints may be
  5010 required);
  5011 
  5012 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5013 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5014 now taken as an integer constant.
  5015 
  5016 * Pure: ML function 'theory_of' renamed to 'theory';
  5017 
  5018 
  5019 *** Proof tools ***
  5020 
  5021 * Simplifier:
  5022   1. Asm_full_simp_tac is now more aggressive.
  5023      1. It will sometimes reorient premises if that increases their power to
  5024         simplify.
  5025      2. It does no longer proceed strictly from left to right but may also
  5026         rotate premises to achieve further simplification.
  5027      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5028      old Asm_full_simp_tac in that it does not rotate premises.
  5029   2. The simplifier now knows a little bit about nat-arithmetic.
  5030 
  5031 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5032 allows for selected deletion of wrappers, by introduction of names for
  5033 wrapper functionals.  This implies that addbefore, addSbefore,
  5034 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5035 and that adding two tactics with the same name overwrites the first
  5036 one (emitting a warning).
  5037   type wrapper = (int -> tactic) -> (int -> tactic)
  5038   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5039   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5040   delWrapper, delSWrapper: claset *  string            -> claset
  5041   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5042 
  5043 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5044 semantics; addbefore now affects only the unsafe part of step_tac
  5045 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5046 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5047 by Force_tac;
  5048 
  5049 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5050 compWrapper; added safe wrapper (and access functions for it);
  5051 
  5052 * HOL/split_all_tac is now much faster and fails if there is nothing
  5053 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5054 and the names of the automatically generated variables have changed.
  5055 split_all_tac has moved within claset() from unsafe wrappers to safe
  5056 wrappers, which means that !!-bound variables are split much more
  5057 aggressively, and safe_tac and clarify_tac now split such variables.
  5058 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5059 Note: the same holds for record_split_tac, which does the job of
  5060 split_all_tac for record fields.
  5061 
  5062 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5063 permanently to the default simpset using Addsplits just like
  5064 Addsimps. They can be removed via Delsplits just like
  5065 Delsimps. Lower-case versions are also available.
  5066 
  5067 * HOL/Simplifier: The rule split_if is now part of the default
  5068 simpset. This means that the simplifier will eliminate all occurrences
  5069 of if-then-else in the conclusion of a goal. To prevent this, you can
  5070 either remove split_if completely from the default simpset by
  5071 `Delsplits [split_if]' or remove it in a specific call of the
  5072 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5073 other case splitting rules to/from the default simpset: every datatype
  5074 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5075 t is the name of the datatype).
  5076 
  5077 * Classical reasoner / Simplifier combination: new force_tac (and
  5078 derivatives Force_tac, force) combines rewriting and classical
  5079 reasoning (and whatever other tools) similarly to auto_tac, but is
  5080 aimed to solve the given subgoal completely.
  5081 
  5082 
  5083 *** General ***
  5084 
  5085 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5086 and `goalw': the theory is no longer needed as an explicit argument -
  5087 the current theory context is used; assumptions are no longer returned
  5088 at the ML-level unless one of them starts with ==> or !!; it is
  5089 recommended to convert to these new commands using isatool fixgoal
  5090 (backup your sources first!);
  5091 
  5092 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5093 the current theory context, and 'theory' to lookup stored theories;
  5094 
  5095 * new theory section 'locale' for declaring constants, assumptions and
  5096 definitions that have local scope;
  5097 
  5098 * new theory section 'nonterminals' for purely syntactic types;
  5099 
  5100 * new theory section 'setup' for generic ML setup functions
  5101 (e.g. package initialization);
  5102 
  5103 * the distribution now includes Isabelle icons: see
  5104 lib/logo/isabelle-{small,tiny}.xpm;
  5105 
  5106 * isatool install - install binaries with absolute references to
  5107 ISABELLE_HOME/bin;
  5108 
  5109 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5110 
  5111 * print mode 'emacs' reserved for Isamode;
  5112 
  5113 * support multiple print (ast) translations per constant name;
  5114 
  5115 * theorems involving oracles are now printed with a suffixed [!];
  5116 
  5117 
  5118 *** HOL ***
  5119 
  5120 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5121 
  5122 * HOL/inductive package reorganized and improved: now supports mutual
  5123 definitions such as
  5124 
  5125   inductive EVEN ODD
  5126     intrs
  5127       null "0 : EVEN"
  5128       oddI "n : EVEN ==> Suc n : ODD"
  5129       evenI "n : ODD ==> Suc n : EVEN"
  5130 
  5131 new theorem list "elims" contains an elimination rule for each of the
  5132 recursive sets; inductive definitions now handle disjunctive premises
  5133 correctly (also ZF);
  5134 
  5135 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5136 "mutual_induct" no longer exists - the induction rule is always
  5137 contained in "induct";
  5138 
  5139 
  5140 * HOL/datatype package re-implemented and greatly improved: now
  5141 supports mutually recursive datatypes such as
  5142 
  5143   datatype
  5144     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5145             | SUM ('a aexp) ('a aexp)
  5146             | DIFF ('a aexp) ('a aexp)
  5147             | NUM 'a
  5148   and
  5149     'a bexp = LESS ('a aexp) ('a aexp)
  5150             | AND ('a bexp) ('a bexp)
  5151             | OR ('a bexp) ('a bexp)
  5152 
  5153 as well as indirectly recursive datatypes such as
  5154 
  5155   datatype
  5156     ('a, 'b) term = Var 'a
  5157                   | App 'b ((('a, 'b) term) list)
  5158 
  5159 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5160 induction on mutually / indirectly recursive datatypes.
  5161 
  5162 Primrec equations are now stored in theory and can be accessed via
  5163 <function_name>.simps.
  5164 
  5165 INCOMPATIBILITIES:
  5166 
  5167   - Theories using datatypes must now have theory Datatype as an
  5168     ancestor.
  5169   - The specific <typename>.induct_tac no longer exists - use the
  5170     generic induct_tac instead.
  5171   - natE has been renamed to nat.exhaust - use exhaust_tac
  5172     instead of res_inst_tac ... natE. Note that the variable
  5173     names in nat.exhaust differ from the names in natE, this
  5174     may cause some "fragile" proofs to fail.
  5175   - The theorems split_<typename>_case and split_<typename>_case_asm
  5176     have been renamed to <typename>.split and <typename>.split_asm.
  5177   - Since default sorts of type variables are now handled correctly,
  5178     some datatype definitions may have to be annotated with explicit
  5179     sort constraints.
  5180   - Primrec definitions no longer require function name and type
  5181     of recursive argument.
  5182 
  5183 Consider using isatool fixdatatype to adapt your theories and proof
  5184 scripts to the new package (backup your sources first!).
  5185 
  5186 
  5187 * HOL/record package: considerably improved implementation; now
  5188 includes concrete syntax for record types, terms, updates; theorems
  5189 for surjective pairing and splitting !!-bound record variables; proof
  5190 support is as follows:
  5191 
  5192   1) standard conversions (selectors or updates applied to record
  5193 constructor terms) are part of the standard simpset;
  5194 
  5195   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5196 made part of standard simpset and claset via addIffs;
  5197 
  5198   3) a tactic for record field splitting (record_split_tac) is part of
  5199 the standard claset (addSWrapper);
  5200 
  5201 To get a better idea about these rules you may retrieve them via
  5202 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5203 the name of your record type.
  5204 
  5205 The split tactic 3) conceptually simplifies by the following rule:
  5206 
  5207   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5208 
  5209 Thus any record variable that is bound by meta-all will automatically
  5210 blow up into some record constructor term, consequently the
  5211 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5212 solve record problems automatically.
  5213 
  5214 
  5215 * reorganized the main HOL image: HOL/Integ and String loaded by
  5216 default; theory Main includes everything;
  5217 
  5218 * automatic simplification of integer sums and comparisons, using cancellation;
  5219 
  5220 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5221 
  5222 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5223 
  5224 * many new identities for unions, intersections, set difference, etc.;
  5225 
  5226 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5227 called split_if, split_split, split_sum_case and split_nat_case (to go
  5228 with add/delsplits);
  5229 
  5230 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5231 (?x::unit) = (); this is made part of the default simpset, which COULD
  5232 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5233 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5234 unit_abs_eta_conv is added in order to counter the effect of
  5235 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5236 %u.f();
  5237 
  5238 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5239 makes more sense);
  5240 
  5241 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5242   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5243   disjointness reasoning but breaking a few old proofs.
  5244 
  5245 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5246 to 'converse' from 'inverse' (for compatibility with ZF and some
  5247 literature);
  5248 
  5249 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5250 the well-founded relation;
  5251 
  5252 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5253     Compl A.  The "Compl" syntax remains available as input syntax for this
  5254     release ONLY.
  5255 
  5256 * HOL/Update: new theory of function updates:
  5257     f(a:=b) == %x. if x=a then b else f x
  5258 may also be iterated as in f(a:=b,c:=d,...);
  5259 
  5260 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5261 
  5262 * HOL/List:
  5263   - new function list_update written xs[i:=v] that updates the i-th
  5264     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5265   - new function `upt' written [i..j(] which generates the list
  5266     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5267     bound write [i..j], which is a shorthand for [i..j+1(].
  5268   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5269 
  5270 * HOL/Arith:
  5271   - removed 'pred' (predecessor) function;
  5272   - generalized some theorems about n-1;
  5273   - many new laws about "div" and "mod";
  5274   - new laws about greatest common divisors (see theory ex/Primes);
  5275 
  5276 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5277 instead of "inverse";
  5278 
  5279 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5280   of the multiset ordering;
  5281 
  5282 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5283   (not included by default);
  5284 
  5285 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5286 
  5287 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5288   programs, i.e. different program variables may have different types.
  5289 
  5290 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5291   [previously, this check worked only if the rewrite rule was unconditional]
  5292   Now rew can involve either definitions or equalities (either == or =).
  5293 
  5294 
  5295 *** ZF ***
  5296 
  5297 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5298   only the theorems proved on ZF.ML;
  5299 
  5300 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5301   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5302   disjointness reasoning but breaking a few old proofs.
  5303 
  5304 * ZF/Update: new theory of function updates
  5305     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5306   may also be iterated as in f(a:=b,c:=d,...);
  5307 
  5308 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5309 
  5310 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5311   [previously, this check worked only if the rewrite rule was unconditional]
  5312   Now rew can involve either definitions or equalities (either == or =).
  5313 
  5314 * case_tac provided for compatibility with HOL
  5315     (like the old excluded_middle_tac, but with subgoals swapped)
  5316 
  5317 
  5318 *** Internal programming interfaces ***
  5319 
  5320 * Pure: several new basic modules made available for general use, see
  5321 also src/Pure/README;
  5322 
  5323 * improved the theory data mechanism to support encapsulation (data
  5324 kind name replaced by private Object.kind, acting as authorization
  5325 key); new type-safe user interface via functor TheoryDataFun; generic
  5326 print_data function becomes basically useless;
  5327 
  5328 * removed global_names compatibility flag -- all theory declarations
  5329 are qualified by default;
  5330 
  5331 * module Pure/Syntax now offers quote / antiquote translation
  5332 functions (useful for Hoare logic etc. with implicit dependencies);
  5333 see HOL/ex/Antiquote for an example use;
  5334 
  5335 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5336 cterm -> thm;
  5337 
  5338 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5339 subgoal;
  5340 
  5341 * Display.print_goals function moved to Locale.print_goals;
  5342 
  5343 * standard print function for goals supports current_goals_markers
  5344 variable for marking begin of proof, end of proof, start of goal; the
  5345 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5346 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5347 for example;
  5348 
  5349 
  5350 
  5351 New in Isabelle98 (January 1998)
  5352 --------------------------------
  5353 
  5354 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5355 
  5356 * changed lexical syntax of terms / types: dots made part of long
  5357 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5358 
  5359 * simpset (and claset) reference variable replaced by functions
  5360 simpset / simpset_ref;
  5361 
  5362 * no longer supports theory aliases (via merge) and non-trivial
  5363 implicit merge of thms' signatures;
  5364 
  5365 * most internal names of constants changed due to qualified names;
  5366 
  5367 * changed Pure/Sequence interface (see Pure/seq.ML);
  5368 
  5369 
  5370 *** General Changes ***
  5371 
  5372 * hierachically structured name spaces (for consts, types, axms, thms
  5373 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5374 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5375 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5376 long_names for fully qualified output names; NOTE: ML programs
  5377 (special tactics, packages etc.) referring to internal names may have
  5378 to be adapted to cope with fully qualified names; in case of severe
  5379 backward campatibility problems try setting 'global_names' at compile
  5380 time to have enrything declared within a flat name space; one may also
  5381 fine tune name declarations in theories via the 'global' and 'local'
  5382 section;
  5383 
  5384 * reimplemented the implicit simpset and claset using the new anytype
  5385 data filed in signatures; references simpset:simpset ref etc. are
  5386 replaced by functions simpset:unit->simpset and
  5387 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5388 to patch your ML files accordingly;
  5389 
  5390 * HTML output now includes theory graph data for display with Java
  5391 applet or isatool browser; data generated automatically via isatool
  5392 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5393 
  5394 * defs may now be conditional; improved rewrite_goals_tac to handle
  5395 conditional equations;
  5396 
  5397 * defs now admits additional type arguments, using TYPE('a) syntax;
  5398 
  5399 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5400 creates a new theory node; implicit merge of thms' signatures is
  5401 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5402 transfer:theory->thm->thm in (rare) cases;
  5403 
  5404 * improved handling of draft signatures / theories; draft thms (and
  5405 ctyps, cterms) are automatically promoted to real ones;
  5406 
  5407 * slightly changed interfaces for oracles: admit many per theory, named
  5408 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5409 
  5410 * print_goals: optional output of const types (set show_consts and
  5411 show_types);
  5412 
  5413 * improved output of warnings (###) and errors (***);
  5414 
  5415 * subgoal_tac displays a warning if the new subgoal has type variables;
  5416 
  5417 * removed old README and Makefiles;
  5418 
  5419 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5420 
  5421 * removed obsolete init_pps and init_database;
  5422 
  5423 * deleted the obsolete tactical STATE, which was declared by
  5424     fun STATE tacfun st = tacfun st st;
  5425 
  5426 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5427 (which abbreviates $HOME);
  5428 
  5429 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5430 use isatool fixseq to adapt your ML programs (this works for fully
  5431 qualified references to the Sequence structure only!);
  5432 
  5433 * use_thy no longer requires writable current directory; it always
  5434 reloads .ML *and* .thy file, if either one is out of date;
  5435 
  5436 
  5437 *** Classical Reasoner ***
  5438 
  5439 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5440 tactics that use classical reasoning to simplify a subgoal without
  5441 splitting it into several subgoals;
  5442 
  5443 * Safe_tac: like safe_tac but uses the default claset;
  5444 
  5445 
  5446 *** Simplifier ***
  5447 
  5448 * added simplification meta rules:
  5449     (asm_)(full_)simplify: simpset -> thm -> thm;
  5450 
  5451 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5452 logics (again);
  5453 
  5454 * added prems argument to simplification procedures;
  5455 
  5456 * HOL, FOL, ZF: added infix function `addsplits':
  5457   instead of `<simpset> setloop (split_tac <thms>)'
  5458   you can simply write `<simpset> addsplits <thms>'
  5459 
  5460 
  5461 *** Syntax ***
  5462 
  5463 * TYPE('a) syntax for type reflection terms;
  5464 
  5465 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5466 
  5467 * pretty printer: changed order of mixfix annotation preference (again!);
  5468 
  5469 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5470 
  5471 
  5472 *** HOL ***
  5473 
  5474 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5475   with `addloop' of the simplifier to faciliate case splitting in premises.
  5476 
  5477 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5478 
  5479 * HOL/Auth: new protocol proofs including some for the Internet
  5480   protocol TLS;
  5481 
  5482 * HOL/Map: new theory of `maps' a la VDM;
  5483 
  5484 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5485 cancelling out common nat summands from =, <, <= (in)equalities, or
  5486 differences; simplification procedures nat_cancel_factor for
  5487 cancelling common factor from =, <, <= (in)equalities over natural
  5488 sums; nat_cancel contains both kinds of procedures, it is installed by
  5489 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5490 
  5491 * HOL/simplifier: terms of the form
  5492   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5493   are rewritten to
  5494   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5495   and those of the form
  5496   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5497   are rewritten to
  5498   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5499 
  5500 * HOL/datatype
  5501   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5502 
  5503   P(t_case f1 ... fn x) =
  5504      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5505         ...
  5506        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5507      )
  5508 
  5509   and a theorem `split_t_case_asm' of the form
  5510 
  5511   P(t_case f1 ... fn x) =
  5512     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5513         ...
  5514        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5515      )
  5516   which can be added to a simpset via `addsplits'. The existing theorems
  5517   expand_list_case and expand_option_case have been renamed to
  5518   split_list_case and split_option_case.
  5519 
  5520 * HOL/Arithmetic:
  5521   - `pred n' is automatically converted to `n-1'.
  5522     Users are strongly encouraged not to use `pred' any longer,
  5523     because it will disappear altogether at some point.
  5524   - Users are strongly encouraged to write "0 < n" rather than
  5525     "n ~= 0". Theorems and proof tools have been modified towards this
  5526     `standard'.
  5527 
  5528 * HOL/Lists:
  5529   the function "set_of_list" has been renamed "set" (and its theorems too);
  5530   the function "nth" now takes its arguments in the reverse order and
  5531   has acquired the infix notation "!" as in "xs!n".
  5532 
  5533 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5534 
  5535 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5536   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5537 
  5538 * HOL/record: extensible records with schematic structural subtyping
  5539 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5540 still lacks various theorems and concrete record syntax;
  5541 
  5542 
  5543 *** HOLCF ***
  5544 
  5545 * removed "axioms" and "generated by" sections;
  5546 
  5547 * replaced "ops" section by extended "consts" section, which is capable of
  5548   handling the continuous function space "->" directly;
  5549 
  5550 * domain package:
  5551   . proves theorems immediately and stores them in the theory,
  5552   . creates hierachical name space,
  5553   . now uses normal mixfix annotations (instead of cinfix...),
  5554   . minor changes to some names and values (for consistency),
  5555   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5556   . separator between mutual domain defs: changed "," to "and",
  5557   . improved handling of sort constraints;  now they have to
  5558     appear on the left-hand side of the equations only;
  5559 
  5560 * fixed LAM <x,y,zs>.b syntax;
  5561 
  5562 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5563 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5564 
  5565 
  5566 *** FOL and ZF ***
  5567 
  5568 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5569   with `addloop' of the simplifier to faciliate case splitting in premises.
  5570 
  5571 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5572 in HOL, they strip ALL and --> from proved theorems;
  5573 
  5574 
  5575 
  5576 New in Isabelle94-8 (May 1997)
  5577 ------------------------------
  5578 
  5579 *** General Changes ***
  5580 
  5581 * new utilities to build / run / maintain Isabelle etc. (in parts
  5582 still somewhat experimental); old Makefiles etc. still functional;
  5583 
  5584 * new 'Isabelle System Manual';
  5585 
  5586 * INSTALL text, together with ./configure and ./build scripts;
  5587 
  5588 * reimplemented type inference for greater efficiency, better error
  5589 messages and clean internal interface;
  5590 
  5591 * prlim command for dealing with lots of subgoals (an easier way of
  5592 setting goals_limit);
  5593 
  5594 
  5595 *** Syntax ***
  5596 
  5597 * supports alternative (named) syntax tables (parser and pretty
  5598 printer); internal interface is provided by add_modesyntax(_i);
  5599 
  5600 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5601 be used in conjunction with the Isabelle symbol font; uses the
  5602 "symbols" syntax table;
  5603 
  5604 * added token_translation interface (may translate name tokens in
  5605 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5606 the current print_mode); IMPORTANT: user print translation functions
  5607 are responsible for marking newly introduced bounds
  5608 (Syntax.mark_boundT);
  5609 
  5610 * token translations for modes "xterm" and "xterm_color" that display
  5611 names in bold, underline etc. or colors (which requires a color
  5612 version of xterm);
  5613 
  5614 * infixes may now be declared with names independent of their syntax;
  5615 
  5616 * added typed_print_translation (like print_translation, but may
  5617 access type of constant);
  5618 
  5619 
  5620 *** Classical Reasoner ***
  5621 
  5622 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5623 some limitations.  Blast_tac...
  5624   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5625   + ignores elimination rules that don't have the correct format
  5626         (the conclusion MUST be a formula variable)
  5627   + ignores types, which can make HOL proofs fail
  5628   + rules must not require higher-order unification, e.g. apply_type in ZF
  5629     [message "Function Var's argument not a bound variable" relates to this]
  5630   + its proof strategy is more general but can actually be slower
  5631 
  5632 * substitution with equality assumptions no longer permutes other
  5633 assumptions;
  5634 
  5635 * minor changes in semantics of addafter (now called addaltern); renamed
  5636 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5637 (and access functions for it);
  5638 
  5639 * improved combination of classical reasoner and simplifier:
  5640   + functions for handling clasimpsets
  5641   + improvement of addss: now the simplifier is called _after_ the
  5642     safe steps.
  5643   + safe variant of addss called addSss: uses safe simplifications
  5644     _during_ the safe steps. It is more complete as it allows multiple
  5645     instantiations of unknowns (e.g. with slow_tac).
  5646 
  5647 *** Simplifier ***
  5648 
  5649 * added interface for simplification procedures (functions that
  5650 produce *proven* rewrite rules on the fly, depending on current
  5651 redex);
  5652 
  5653 * ordering on terms as parameter (used for ordered rewriting);
  5654 
  5655 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5656 
  5657 * the solver is now split into a safe and an unsafe part.
  5658 This should be invisible for the normal user, except that the
  5659 functions setsolver and addsolver have been renamed to setSolver and
  5660 addSolver; added safe_asm_full_simp_tac;
  5661 
  5662 
  5663 *** HOL ***
  5664 
  5665 * a generic induction tactic `induct_tac' which works for all datatypes and
  5666 also for type `nat';
  5667 
  5668 * a generic case distinction tactic `exhaust_tac' which works for all
  5669 datatypes and also for type `nat';
  5670 
  5671 * each datatype comes with a function `size';
  5672 
  5673 * patterns in case expressions allow tuple patterns as arguments to
  5674 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5675 
  5676 * primrec now also works with type nat;
  5677 
  5678 * recdef: a new declaration form, allows general recursive functions to be
  5679 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5680 
  5681 * the constant for negation has been renamed from "not" to "Not" to
  5682 harmonize with FOL, ZF, LK, etc.;
  5683 
  5684 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5685 infinite lists;
  5686 
  5687 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5688 
  5689 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  5690 problems in commutative rings, using axiomatic type classes for + and *;
  5691 
  5692 * more examples in HOL/MiniML and HOL/Auth;
  5693 
  5694 * more default rewrite rules for quantifiers, union/intersection;
  5695 
  5696 * a new constant `arbitrary == @x.False';
  5697 
  5698 * HOLCF/IOA replaces old HOL/IOA;
  5699 
  5700 * HOLCF changes: derived all rules and arities
  5701   + axiomatic type classes instead of classes
  5702   + typedef instead of faking type definitions
  5703   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5704   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5705   + eliminated the types void, one, tr
  5706   + use unit lift and bool lift (with translations) instead of one and tr
  5707   + eliminated blift from Lift3.thy (use Def instead of blift)
  5708   all eliminated rules are derived as theorems --> no visible changes ;
  5709 
  5710 
  5711 *** ZF ***
  5712 
  5713 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5714 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5715 as ZF_cs addSIs [equalityI];
  5716 
  5717 
  5718 
  5719 New in Isabelle94-7 (November 96)
  5720 ---------------------------------
  5721 
  5722 * allowing negative levels (as offsets) in prlev and choplev;
  5723 
  5724 * super-linear speedup for large simplifications;
  5725 
  5726 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  5727 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  5728 FAIL); can suppress it using the command Delsimps (ex_simps @
  5729 all_simps); De Morgan laws are also now included, by default;
  5730 
  5731 * improved printing of ==>  :  ~:
  5732 
  5733 * new object-logic "Sequents" adds linear logic, while replacing LK
  5734 and Modal (thanks to Sara Kalvala);
  5735 
  5736 * HOL/Auth: correctness proofs for authentication protocols;
  5737 
  5738 * HOL: new auto_tac combines rewriting and classical reasoning (many
  5739 examples on HOL/Auth);
  5740 
  5741 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  5742 the rewriter and classical reasoner simultaneously;
  5743 
  5744 * function uresult no longer returns theorems in "standard" format;
  5745 regain previous version by: val uresult = standard o uresult;
  5746 
  5747 
  5748 
  5749 New in Isabelle94-6
  5750 -------------------
  5751 
  5752 * oracles -- these establish an interface between Isabelle and trusted
  5753 external reasoners, which may deliver results as theorems;
  5754 
  5755 * proof objects (in particular record all uses of oracles);
  5756 
  5757 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  5758 
  5759 * "constdefs" section in theory files;
  5760 
  5761 * "primrec" section (HOL) no longer requires names;
  5762 
  5763 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  5764 
  5765 
  5766 
  5767 New in Isabelle94-5
  5768 -------------------
  5769 
  5770 * reduced space requirements;
  5771 
  5772 * automatic HTML generation from theories;
  5773 
  5774 * theory files no longer require "..." (quotes) around most types;
  5775 
  5776 * new examples, including two proofs of the Church-Rosser theorem;
  5777 
  5778 * non-curried (1994) version of HOL is no longer distributed;
  5779 
  5780 
  5781 
  5782 New in Isabelle94-4
  5783 -------------------
  5784 
  5785 * greatly reduced space requirements;
  5786 
  5787 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5788 
  5789 * searchable theorem database (see the section "Retrieving theorems" on
  5790 page 8 of the Reference Manual);
  5791 
  5792 * new examples, including Grabczewski's monumental case study of the
  5793 Axiom of Choice;
  5794 
  5795 * The previous version of HOL renamed to Old_HOL;
  5796 
  5797 * The new version of HOL (previously called CHOL) uses a curried syntax
  5798 for functions.  Application looks like f a b instead of f(a,b);
  5799 
  5800 * Mutually recursive inductive definitions finally work in HOL;
  5801 
  5802 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5803 translates to the operator "split";
  5804 
  5805 
  5806 
  5807 New in Isabelle94-3
  5808 -------------------
  5809 
  5810 * new infix operator, addss, allowing the classical reasoner to
  5811 perform simplification at each step of its search.  Example:
  5812         fast_tac (cs addss ss)
  5813 
  5814 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5815 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5816 look like (a,b) instead of <a,b>;
  5817 
  5818 * PLEASE NOTE: CHOL will eventually replace HOL!
  5819 
  5820 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5821 It translates to the operator "split".  A new theory of integers is available;
  5822 
  5823 * In ZF, integer numerals now denote two's-complement binary integers.
  5824 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5825 
  5826 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5827 of the Axiom of Choice;
  5828 
  5829 
  5830 
  5831 New in Isabelle94-2
  5832 -------------------
  5833 
  5834 * Significantly faster resolution;
  5835 
  5836 * the different sections in a .thy file can now be mixed and repeated
  5837 freely;
  5838 
  5839 * Database of theorems for FOL, HOL and ZF.  New
  5840 commands including qed, qed_goal and bind_thm store theorems in the database.
  5841 
  5842 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5843 a given theory (thms_of), or find out what theory a theorem was proved in
  5844 (theory_of_thm);
  5845 
  5846 * Bugs fixed in the inductive definition and datatype packages;
  5847 
  5848 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5849 and HOL_dup_cs obsolete;
  5850 
  5851 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5852 have been removed;
  5853 
  5854 * Simpler definition of function space in ZF;
  5855 
  5856 * new results about cardinal and ordinal arithmetic in ZF;
  5857 
  5858 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5859 types;
  5860 
  5861 :mode=text:wrap=hard:maxLineLen=72:
  5862 
  5863 
  5864 $Id$