NEWS
author wenzelm
Sat Nov 29 19:01:28 2008 +0100 (2008-11-29)
changeset 28910 5c712e46988f
parent 28856 5e009a80fe6d
child 28914 f993cbffc42a
permissions -rw-r--r--
tuned;
     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 * Slightly more coherent Pure syntax, with updated documentation in
    51 isar-ref manual.  Removed locales meta_term_syntax and
    52 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
    53 INCOMPATIBILITY in rare situations.
    54 
    55 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
    56 hypotheses.  Sorts required in the course of reasoning need to be
    57 covered by the constraints in the initial statement, completed by the
    58 type instance information of the background theory.  Non-trivial sort
    59 hypotheses, which rarely occur in practice, may be specified via
    60 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
    61 
    62   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
    63 
    64 The result contains an implicit sort hypotheses as before --
    65 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
    66 normalization.
    67 
    68 * Changed defaults for unify configuration options:
    69 
    70   unify_trace_bound = 50 (formerly 25)
    71   unify_search_bound = 60 (formerly 30)
    72 
    73 * Different bookkeeping for code equations:
    74   a) On theory merge, the last set of code equations for a particular constant
    75      is taken (in accordance with the policy applied by other parts of the
    76      code generator framework).
    77   b) Code equations stemming from explicit declarations (e.g. code attribute)
    78      gain priority over default code equations stemming from definition, primrec,
    79      fun etc.
    80   INCOMPATIBILITY.
    81 
    82 * Global versions of theorems stemming from classes do not carry
    83 a parameter prefix any longer.  INCOMPATIBILITY.
    84 
    85 * Dropped locale element "includes".  This is a major INCOMPATIBILITY.
    86 In existing theorem specifications replace the includes element by the
    87 respective context elements of the included locale, omitting those that
    88 are already present in the theorem specification.  Multiple assume
    89 elements of a locale should be replaced by a single one involving the
    90 locale predicate.  In the proof body, declarations (most notably
    91 theorems) may be regained by interpreting the respective locales in the
    92 proof context as required (command "interpret").
    93 If using "includes" in replacement of a target solely because the
    94 parameter types in the theorem are not as general as in the target,
    95 consider declaring a new locale with additional type constraints on the
    96 parameters (context element "constrains").
    97 
    98 * Dropped "locale (open)".  INCOMPATBILITY.
    99 
   100 * Interpretation commands no longer attempt to simplify goal.
   101 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   102 methods intro_locales and unfold_locales to clarify.
   103 
   104 * Interpretation commands no longer accept interpretation attributes.
   105 INCOMPATBILITY.
   106 
   107 * Command 'instance': attached definitions no longer accepted.
   108 INCOMPATIBILITY, use proper 'instantiation' target.
   109 
   110 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   111 
   112 * The 'axiomatization' command now only works within a global theory
   113 context.  INCOMPATIBILITY.
   114 
   115 
   116 *** Document preparation ***
   117 
   118 * Antiquotation @{lemma} now imitates a regular terminal proof,
   119 demanding keyword 'by' and supporting the full method expression
   120 syntax just like the Isar command 'by'.
   121 
   122 
   123 *** HOL ***
   124 
   125 * If methods "eval" and "evaluation" encounter a structured proof state
   126 with !!/==>, only the conclusion is evaluated to True (if possible),
   127 avoiding strange error messages.
   128 
   129 * Simplifier: simproc for let expressions now unfolds if bound variable
   130 occurs at most one time in let expression body.  INCOMPATIBILITY.
   131 
   132 * New classes "top" and "bot" with corresponding operations "top" and "bot"
   133 in theory Orderings;  instantiation of class "complete_lattice" requires
   134 instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   135 
   136 * Changed definition lemma "less_fun_def" in order to provide an instance
   137 for preorders on functions;  use lemma "less_le" instead.  INCOMPATIBILITY.
   138 
   139 * Unified theorem tables for both code code generators.  Thus
   140 [code func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   141 
   142 * Constants "undefined" and "default" replace "arbitrary".  Usually
   143 "undefined" is the right choice to replace "arbitrary", though logically
   144 there is no difference.  INCOMPATIBILITY.
   145 
   146 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   147 Posix processes.  Avoids potentially expensive forking of the ML
   148 process.  New thread-based implementation also works on non-Unix
   149 platforms (Cygwin).  Provers are no longer hardwired, but defined
   150 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   151 commands are covered in the isar-ref manual
   152 
   153 * Wrapper scripts for remote SystemOnTPTP service allows to use
   154 sledgehammer without local ATP installation (Vampire etc.).  See also
   155 ISABELLE_HOME/contrib/SystemOnTPTP and the VAMPIRE_HOME setting
   156 variable.  Other provers may be included via suitable ML wrappers, see
   157 also src/HOL/ATP_Linkup.thy.
   158 
   159 * Normalization by evaluation now allows non-leftlinear equations.
   160 Declare with attribute [code nbe].
   161 
   162 * Command "value" now integrates different evaluation
   163 mechanisms.  The result of the first successful evaluation mechanism
   164 is printed.  In square brackets a particular named evaluation
   165 mechanisms may be specified (currently, [SML], [code] or [nbe]).  See
   166 further src/HOL/ex/Eval_Examples.thy.
   167 
   168 * HOL/Orderings: class "wellorder" moved here, with explicit induction
   169 rule "less_induct" as assumption.  For instantiation of "wellorder" by
   170 means of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.
   171 
   172 * HOL/Orderings: added class "preorder" as superclass of "order".
   173 INCOMPATIBILITY: Instantiation proofs for order, linorder
   174 etc. slightly changed.  Some theorems named order_class.* now named
   175 preorder_class.*.
   176 
   177 * HOL/Finite_Set: added a new fold combinator of type
   178   ('a => 'b => 'b) => 'b => 'a set => 'b
   179 Occasionally this is more convenient than the old fold combinator which is
   180 now defined in terms of the new one and renamed to fold_image.
   181 
   182 * HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
   183 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   184 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   185 of lemmas from Divides has been generalized from nat to class
   186 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   187 renames resulting from duplicate elimination:
   188 
   189     dvd_def_mod ~>          dvd_eq_mod_eq_0
   190     zero_dvd_iff ~>         dvd_0_left_iff
   191     dvd_0 ~>                dvd_0_right
   192     DIVISION_BY_ZERO_DIV ~> div_by_0
   193     DIVISION_BY_ZERO_MOD ~> mod_by_0
   194     mult_div ~>             div_mult_self2_is_id
   195     mult_mod ~>             mod_mult_self2_is_0
   196 
   197 * HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   198 zlcm (for int); carried together from various gcd/lcm developements in
   199 the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
   200 corresponding theorems renamed accordingly.  INCOMPATIBILY.  To
   201 recover tupled syntax, use syntax declarations like:
   202 
   203     hide (open) const gcd
   204     abbreviation gcd where
   205       "gcd == (%(a, b). GCD.gcd a b)"
   206     notation (output)
   207       GCD.gcd ("gcd '(_, _')")
   208 
   209 (analogously for lcm, zgcd, zlcm).
   210 
   211 * HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   212 
   213 * New ML antiquotation @{code}: takes constant as argument, generates
   214 corresponding code in background and inserts name of the corresponding
   215 resulting ML value/function/datatype constructor binding in place.
   216 All occurrences of @{code} with a single ML block are generated
   217 simultaneously.  Provides a generic and safe interface for
   218 instrumentalizing code generation.  See HOL/ex/Code_Antiq for a toy
   219 example, or HOL/Complex/ex/ReflectedFerrack for a more ambitious
   220 application.  In future you ought refrain from ad-hoc compiling
   221 generated SML code on the ML toplevel.  Note that (for technical
   222 reasons) @{code} cannot refer to constants for which user-defined
   223 serializations are set.  Refer to the corresponding ML counterpart
   224 directly in that cases.
   225 
   226 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   227 Complex_Main.thy remain as they are.
   228 
   229 * New image HOL-Plain provides a minimal HOL with the most important
   230 tools available (inductive, datatype, primrec, ...).  By convention
   231 the corresponding theory Plain should be ancestor of every further
   232 (library) theory.  Some library theories now have ancestor Plain
   233 (instead of Main), thus theory Main occasionally has to be imported
   234 explicitly.
   235 
   236 * The metis method now fails in the usual manner, rather than raising
   237 an exception, if it determines that it cannot prove the theorem.
   238 
   239 * The metis method no longer fails because the theorem is too trivial
   240 (contains the empty clause).
   241 
   242 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   243 as the structured Isar versions "cases" and "induct", cf. the
   244 corresponding "cases" and "induct" attributes.  Mutual induction rules
   245 are now presented as a list of individual projections
   246 (e.g. foo_bar.inducts for types foo and bar); the old format with
   247 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   248 rare situations a different rule is selected --- notably nested tuple
   249 elimination instead of former prod.exhaust: use explicit (case_tac t
   250 rule: prod.exhaust) here.
   251 
   252 * Attributes "cases", "induct", "coinduct" support "del" option.
   253 
   254 * Removed fact "case_split_thm", which duplicates "case_split".
   255 
   256 * Command 'rep_datatype': instead of theorem names the command now
   257 takes a list of terms denoting the constructors of the type to be
   258 represented as datatype.  The characteristic theorems have to be
   259 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   260 have disappeared in favour of existing ones:
   261 
   262     unit_induct                 ~> unit.induct
   263     prod_induct                 ~> prod.induct
   264     sum_induct                  ~> sum.induct
   265     Suc_Suc_eq                  ~> nat.inject
   266     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   267 
   268 * Library/Nat_Infinity: added addition, numeral syntax and more
   269 instantiations for algebraic structures.  Removed some duplicate
   270 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   271 
   272 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   273 menu.
   274 
   275 
   276 *** HOL-Algebra ***
   277 
   278 * New locales for orders and lattices where the equivalence relation
   279   is not restricted to equality.  INCOMPATIBILITY: all order and
   280   lattice locales use a record structure with field eq for the
   281   equivalence.
   282 
   283 * New theory of factorial domains.
   284 
   285 * Units_l_inv and Units_r_inv are now simprules by default.
   286 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   287 and/or r_inv will now also require deletion of these lemmas.
   288 
   289 * Renamed the following theorems.  INCOMPATIBILITY.
   290 UpperD ~> Upper_memD
   291 LowerD ~> Lower_memD
   292 least_carrier ~> least_closed
   293 greatest_carrier ~> greatest_closed
   294 greatest_Lower_above ~> greatest_Lower_below
   295 one_zero ~> carrier_one_zero
   296 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   297 
   298 
   299 *** HOL-NSA ***
   300 
   301 * Created new image HOL-NSA, containing theories of nonstandard
   302 analysis which were previously part of HOL-Complex.  Entry point
   303 Hyperreal.thy remains valid, but theories formerly using
   304 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   305 
   306 
   307 *** ZF ***
   308 
   309 * Proof of Zorn's Lemma for partial orders.
   310 
   311 
   312 *** ML ***
   313 
   314 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   315 to 'a -> thm, while results are always tagged with an authentic oracle
   316 name.  The Isar command 'oracle' is now polymorphic, no argument type
   317 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   318 accordingly.  Note that extra performance may be gained by producing
   319 the cterm carefully, avoiding slow Thm.cterm_of.
   320 
   321 * ML bindings produced via Isar commands are stored within the Isar
   322 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   323 become thread-safe and work with undo as expected (concerning
   324 top-level bindings, not side-effects on global references).
   325 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   326 compiler at runtime; really global bindings need to be given outside a
   327 theory. [Poly/ML 5.2 or later]
   328 
   329 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   330 context. Top-level ML bindings are stored within the proof context in
   331 a purely sequential fashion, disregarding the nested proof structure.
   332 ML bindings introduced by 'ML_prf' are discarded at the end of the
   333 proof.  [Poly/ML 5.2 or later]
   334 
   335 * Generic Toplevel.add_hook interface allows to analyze the result of
   336 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   337 for theorem dependency output of transactions resulting in a new
   338 theory state.
   339 
   340 * Name bindings in higher specification mechanisms (notably
   341 LocalTheory.define, LocalTheory.note, and derived packages) are now
   342 formalized as type Name.binding, replacing old bstring.
   343 INCOMPATIBILITY, need to wrap strings via Name.binding function, see
   344 also Name.name_of.  Packages should pass name bindings given by the
   345 user to underlying specification mechanisms; this enables precise
   346 tracking of source positions, for example.
   347 
   348 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   349 LocalTheory.note etc.) now refer to the *full* internal name, not the
   350 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   351 
   352 * Rules and tactics that read instantiations (read_instantiate,
   353 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   354 context, which is required for parsing and type-checking.  Moreover,
   355 the variables are specified as plain indexnames, not string encodings
   356 thereof.  INCOMPATIBILITY.
   357 
   358 * Disposed old type and term read functions (Sign.read_def_typ,
   359 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   360 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   361 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   362 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   363 resort for legacy applications.
   364 
   365 * Antiquotations: block-structured compilation context indicated by
   366 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   367 
   368   @{let ?pat = term}                      - term abbreviation (HO matching)
   369   @{note name = fact}                     - fact abbreviation
   370   @{thm fact}                             - singleton fact (with attributes)
   371   @{thms fact}                            - general fact (with attributes)
   372   @{lemma prop by method}                 - singleton goal
   373   @{lemma prop by meth1 meth2}            - singleton goal
   374   @{lemma prop1 ... propN by method}      - general goal
   375   @{lemma prop1 ... propN by meth1 meth2} - general goal
   376   @{lemma (open) ...}                     - open derivation
   377 
   378 
   379 *** System ***
   380 
   381 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   382 Poly/ML 5.2.1 or later.
   383 
   384 * The Isabelle "emacs" tool provides a specific interface to invoke
   385 Proof General / Emacs, with more explicit failure if that is not
   386 installed (the old isabelle-interface script silently falls back on
   387 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   388 installation location of the Proof General distribution.
   389 
   390 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   391 the Isabelle process into a JVM/Scala application.  See
   392 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   393 process wrapper has been discontinued.)
   394 
   395 * Status messages (with exact source position information) are
   396 emitted, if proper markup print mode is enabled.  This allows
   397 user-interface components to provide detailed feedback on internal
   398 prover operations.
   399 
   400 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   401 
   402 
   403 
   404 New in Isabelle2008 (June 2008)
   405 -------------------------------
   406 
   407 *** General ***
   408 
   409 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   410 and updated, with formally checked references as hyperlinks.
   411 
   412 * Theory loader: use_thy (and similar operations) no longer set the
   413 implicit ML context, which was occasionally hard to predict and in
   414 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   415 provides a proper context already.
   416 
   417 * Theory loader: old-style ML proof scripts being *attached* to a thy
   418 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   419 'use' within a theory file will do the job.
   420 
   421 * Name space merge now observes canonical order, i.e. the second space
   422 is inserted into the first one, while existing entries in the first
   423 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   424 swap theory imports.
   425 
   426 * Syntax: symbol \<chi> is now considered a letter.  Potential
   427 INCOMPATIBILITY in identifier syntax etc.
   428 
   429 * Outer syntax: string tokens no longer admit escaped white space,
   430 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   431 white space without escapes.
   432 
   433 * Outer syntax: string tokens may contain arbitrary character codes
   434 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   435 "foo_bar".
   436 
   437 
   438 *** Pure ***
   439 
   440 * Context-dependent token translations.  Default setup reverts locally
   441 fixed variables, and adds hilite markup for undeclared frees.
   442 
   443 * Unused theorems can be found using the new command 'unused_thms'.
   444 There are three ways of invoking it:
   445 
   446 (1) unused_thms
   447      Only finds unused theorems in the current theory.
   448 
   449 (2) unused_thms thy_1 ... thy_n -
   450      Finds unused theorems in the current theory and all of its ancestors,
   451      excluding the theories thy_1 ... thy_n and all of their ancestors.
   452 
   453 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   454      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   455      their ancestors, excluding the theories thy_1 ... thy_n and all of
   456      their ancestors.
   457 
   458 In order to increase the readability of the list produced by
   459 unused_thms, theorems that have been created by a particular instance
   460 of a theory command such as 'inductive' or 'function' are considered
   461 to belong to the same "group", meaning that if at least one theorem in
   462 this group is used, the other theorems in the same group are no longer
   463 reported as unused.  Moreover, if all theorems in the group are
   464 unused, only one theorem in the group is displayed.
   465 
   466 Note that proof objects have to be switched on in order for
   467 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   468 usually the case when using Proof General with the default settings).
   469 
   470 * Authentic naming of facts disallows ad-hoc overwriting of previous
   471 theorems within the same name space.  INCOMPATIBILITY, need to remove
   472 duplicate fact bindings, or even accidental fact duplications.  Note
   473 that tools may maintain dynamically scoped facts systematically, using
   474 PureThy.add_thms_dynamic.
   475 
   476 * Command 'hide' now allows to hide from "fact" name space as well.
   477 
   478 * Eliminated destructive theorem database, simpset, claset, and
   479 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   480 update of theories within ML code.
   481 
   482 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   483 INCOMPATIBILITY, object-logics depending on former Pure require
   484 additional setup PureThy.old_appl_syntax_setup; object-logics
   485 depending on former CPure need to refer to Pure.
   486 
   487 * Commands 'use' and 'ML' are now purely functional, operating on
   488 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   489 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   490 INCOMPATIBILITY.
   491 
   492 * Command 'setup': discontinued implicit version with ML reference.
   493 
   494 * Instantiation target allows for simultaneous specification of class
   495 instance operations together with an instantiation proof.
   496 Type-checking phase allows to refer to class operations uniformly.
   497 See src/HOL/Complex/Complex.thy for an Isar example and
   498 src/HOL/Library/Eval.thy for an ML example.
   499 
   500 * Indexing of literal facts: be more serious about including only
   501 facts from the visible specification/proof context, but not the
   502 background context (locale etc.).  Affects `prop` notation and method
   503 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   504 situations.
   505 
   506 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   507 "(open)" option, which used to expose internal bound variables to the
   508 proof text.
   509 
   510 * Isar statements: removed obsolete case "rule_context".
   511 INCOMPATIBILITY, better use explicit fixes/assumes.
   512 
   513 * Locale proofs: default proof step now includes 'unfold_locales';
   514 hence 'proof' without argument may be used to unfold locale
   515 predicates.
   516 
   517 
   518 *** Document preparation ***
   519 
   520 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   521 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   522 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   523 spot); renamed link color from "darkblue" to "linkcolor" (default
   524 value unchanged, can be redefined via \definecolor); no longer sets
   525 "a4paper" option (unnecessary or even intrusive).
   526 
   527 * Antiquotation @{lemma A method} proves proposition A by the given
   528 method (either a method name or a method name plus (optional) method
   529 arguments in parentheses) and prints A just like @{prop A}.
   530 
   531 
   532 *** HOL ***
   533 
   534 * New primrec package.  Specification syntax conforms in style to
   535 definition/function/....  No separate induction rule is provided.  The
   536 "primrec" command distinguishes old-style and new-style specifications
   537 by syntax.  The former primrec package is now named OldPrimrecPackage.
   538 When adjusting theories, beware: constants stemming from new-style
   539 primrec specifications have authentic syntax.
   540 
   541 * Metis prover is now an order of magnitude faster, and also works
   542 with multithreading.
   543 
   544 * Metis: the maximum number of clauses that can be produced from a
   545 theorem is now given by the attribute max_clauses.  Theorems that
   546 exceed this number are ignored, with a warning printed.
   547 
   548 * Sledgehammer no longer produces structured proofs by default. To
   549 enable, declare [[sledgehammer_full = true]].  Attributes
   550 reconstruction_modulus, reconstruction_sorts renamed
   551 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   552 
   553 * Method "induct_scheme" derives user-specified induction rules
   554 from well-founded induction and completeness of patterns. This factors
   555 out some operations that are done internally by the function package
   556 and makes them available separately.  See
   557 src/HOL/ex/Induction_Scheme.thy for examples.
   558 
   559 * More flexible generation of measure functions for termination
   560 proofs: Measure functions can be declared by proving a rule of the
   561 form "is_measure f" and giving it the [measure_function] attribute.
   562 The "is_measure" predicate is logically meaningless (always true), and
   563 just guides the heuristic.  To find suitable measure functions, the
   564 termination prover sets up the goal "is_measure ?f" of the appropriate
   565 type and generates all solutions by prolog-style backwards proof using
   566 the declared rules.
   567 
   568 This setup also deals with rules like 
   569 
   570   "is_measure f ==> is_measure (list_size f)"
   571 
   572 which accommodates nested datatypes that recurse through lists.
   573 Similar rules are predeclared for products and option types.
   574 
   575 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   576 
   577   INCOMPATIBILITIES:
   578 
   579   - Definitions of overloaded constants on sets have to be replaced by
   580     definitions on => and bool.
   581 
   582   - Some definitions of overloaded operators on sets can now be proved
   583     using the definitions of the operators on => and bool.  Therefore,
   584     the following theorems have been renamed:
   585 
   586       subset_def   -> subset_eq
   587       psubset_def  -> psubset_eq
   588       set_diff_def -> set_diff_eq
   589       Compl_def    -> Compl_eq
   590       Sup_set_def  -> Sup_set_eq
   591       Inf_set_def  -> Inf_set_eq
   592       sup_set_def  -> sup_set_eq
   593       inf_set_def  -> inf_set_eq
   594 
   595   - Due to the incompleteness of the HO unification algorithm, some
   596     rules such as subst may require manual instantiation, if some of
   597     the unknowns in the rule is a set.
   598 
   599   - Higher order unification and forward proofs:
   600     The proof pattern
   601 
   602       have "P (S::'a set)" <...>
   603       then have "EX S. P S" ..
   604 
   605     no longer works (due to the incompleteness of the HO unification
   606     algorithm) and must be replaced by the pattern
   607 
   608       have "EX S. P S"
   609       proof
   610         show "P S" <...>
   611       qed
   612 
   613   - Calculational reasoning with subst (or similar rules):
   614     The proof pattern
   615 
   616       have "P (S::'a set)" <...>
   617       also have "S = T" <...>
   618       finally have "P T" .
   619 
   620     no longer works (for similar reasons as the previous example) and
   621     must be replaced by something like
   622 
   623       have "P (S::'a set)" <...>
   624       moreover have "S = T" <...>
   625       ultimately have "P T" by simp
   626 
   627   - Tactics or packages written in ML code:
   628     Code performing pattern matching on types via
   629 
   630       Type ("set", [T]) => ...
   631 
   632     must be rewritten. Moreover, functions like strip_type or
   633     binder_types no longer return the right value when applied to a
   634     type of the form
   635 
   636       T1 => ... => Tn => U => bool
   637 
   638     rather than
   639 
   640       T1 => ... => Tn => U set
   641 
   642 * Merged theories Wellfounded_Recursion, Accessible_Part and
   643 Wellfounded_Relations to theory Wellfounded.
   644 
   645 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   646 
   647 * Class finite no longer treats UNIV as class parameter.  Use class
   648 enum from theory Library/Enum instead to achieve a similar effect.
   649 INCOMPATIBILITY.
   650 
   651 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   652 and "Cons".  INCOMPATIBILITY.
   653 
   654 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   655 Potential INCOMPATIBILITY.
   656 
   657 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   658 injective_fst_snd removed, use split_eta and prod_eqI instead.
   659 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   660 
   661 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   662 the same name in theory Orderings:
   663 
   664   less_trans
   665   less_linear
   666   le_imp_less_or_eq
   667   le_less_trans
   668   less_le_trans
   669   less_not_sym
   670   less_asym
   671 
   672 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
   673 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
   674 and different variable names.
   675 
   676 * Library/Option_ord.thy: Canonical order on option type.
   677 
   678 * Library/RBT.thy: Red-black trees, an efficient implementation of
   679 finite maps.
   680 
   681 * Library/Countable.thy: Type class for countable types.
   682 
   683 * Theory Int: The representation of numerals has changed.  The infix
   684 operator BIT and the bit datatype with constructors B0 and B1 have
   685 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
   686 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
   687 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
   688 accordingly.
   689 
   690 * Theory Nat: definition of <= and < on natural numbers no longer
   691 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
   692 le_def and less_def have disappeared.  Consider lemmas not_less
   693 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
   694 
   695 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
   696 (whose purpose mainly is for various fold_set functionals) have been
   697 abandoned in favor of the existing algebraic classes
   698 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
   699 lower_semilattice (resp. upper_semilattice) and linorder.
   700 INCOMPATIBILITY.
   701 
   702 * Theory Transitive_Closure: induct and cases rules now declare proper
   703 case_names ("base" and "step").  INCOMPATIBILITY.
   704 
   705 * Theorem Inductive.lfp_ordinal_induct generalized to complete
   706 lattices.  The form set-specific version is available as
   707 Inductive.lfp_ordinal_induct_set.
   708 
   709 * Renamed theorems "power.simps" to "power_int.simps".
   710 INCOMPATIBILITY.
   711 
   712 * Class semiring_div provides basic abstract properties of semirings
   713 with division and modulo operations.  Subsumes former class dvd_mod.
   714 
   715 * Merged theories IntDef, Numeral and IntArith into unified theory
   716 Int.  INCOMPATIBILITY.
   717 
   718 * Theory Library/Code_Index: type "index" now represents natural
   719 numbers rather than integers.  INCOMPATIBILITY.
   720 
   721 * New class "uminus" with operation "uminus" (split of from class
   722 "minus" which now only has operation "minus", binary).
   723 INCOMPATIBILITY.
   724 
   725 * Constants "card", "internal_split", "option_map" now with authentic
   726 syntax.  INCOMPATIBILITY.
   727 
   728 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
   729 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
   730 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
   731 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
   732 Sup_set_def, le_def, less_def, option_map_def now with object
   733 equality.  INCOMPATIBILITY.
   734 
   735 * Records. Removed K_record, and replaced it by pure lambda term
   736 %x. c. The simplifier setup is now more robust against eta expansion.
   737 INCOMPATIBILITY: in cases explicitly referring to K_record.
   738 
   739 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
   740 
   741 * Library/ListVector: new theory of arithmetic vector operations.
   742 
   743 * Library/Order_Relation: new theory of various orderings as sets of
   744 pairs.  Defines preorders, partial orders, linear orders and
   745 well-orders on sets and on types.
   746 
   747 
   748 *** ZF ***
   749 
   750 * Renamed some theories to allow to loading both ZF and HOL in the
   751 same session:
   752 
   753   Datatype  -> Datatype_ZF
   754   Inductive -> Inductive_ZF
   755   Int       -> Int_ZF
   756   IntDiv    -> IntDiv_ZF
   757   Nat       -> Nat_ZF
   758   List      -> List_ZF
   759   Main      -> Main_ZF
   760 
   761 INCOMPATIBILITY: ZF theories that import individual theories below
   762 Main might need to be adapted.  Regular theory Main is still
   763 available, as trivial extension of Main_ZF.
   764 
   765 
   766 *** ML ***
   767 
   768 * ML within Isar: antiquotation @{const name} or @{const
   769 name(typargs)} produces statically-checked Const term.
   770 
   771 * Functor NamedThmsFun: data is available to the user as dynamic fact
   772 (of the same name).  Removed obsolete print command.
   773 
   774 * Removed obsolete "use_legacy_bindings" function.
   775 
   776 * The ``print mode'' is now a thread-local value derived from a global
   777 template (the former print_mode reference), thus access becomes
   778 non-critical.  The global print_mode reference is for session
   779 management only; user-code should use print_mode_value,
   780 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
   781 
   782 * Functions system/system_out provide a robust way to invoke external
   783 shell commands, with propagation of interrupts (requires Poly/ML 5.2).
   784 Do not use OS.Process.system etc. from the basis library!
   785 
   786 
   787 *** System ***
   788 
   789 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
   790 in accordance with Proof General 3.7, which prefers GNU emacs.
   791 
   792 * isatool tty runs Isabelle process with plain tty interaction;
   793 optional line editor may be specified via ISABELLE_LINE_EDITOR
   794 setting, the default settings attempt to locate "ledit" and "rlwrap".
   795 
   796 * isatool browser now works with Cygwin as well, using general
   797 "javapath" function defined in Isabelle process environment.
   798 
   799 * YXML notation provides a simple and efficient alternative to
   800 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
   801 isatool yxml as described in the Isabelle system manual.
   802 
   803 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
   804 provides general wrapper for managing an Isabelle process in a robust
   805 fashion, with ``cooked'' output from stdin/stderr.
   806 
   807 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
   808 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
   809 
   810 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
   811 way of changing the user's settings is via
   812 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
   813 script.
   814 
   815 * Multithreading.max_threads := 0 refers to the number of actual CPU
   816 cores of the underlying machine, which is a good starting point for
   817 optimal performance tuning.  The corresponding usedir option -M allows
   818 "max" as an alias for "0".  WARNING: does not work on certain versions
   819 of Mac OS (with Poly/ML 5.1).
   820 
   821 * isabelle-process: non-ML sessions are run with "nice", to reduce the
   822 adverse effect of Isabelle flooding interactive front-ends (notably
   823 ProofGeneral / XEmacs).
   824 
   825 
   826 
   827 New in Isabelle2007 (November 2007)
   828 -----------------------------------
   829 
   830 *** General ***
   831 
   832 * More uniform information about legacy features, notably a
   833 warning/error of "Legacy feature: ...", depending on the state of the
   834 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
   835 legacy features will disappear eventually.
   836 
   837 * Theory syntax: the header format ``theory A = B + C:'' has been
   838 discontinued in favour of ``theory A imports B C begin''.  Use isatool
   839 fixheaders to convert existing theory files.  INCOMPATIBILITY.
   840 
   841 * Theory syntax: the old non-Isar theory file format has been
   842 discontinued altogether.  Note that ML proof scripts may still be used
   843 with Isar theories; migration is usually quite simple with the ML
   844 function use_legacy_bindings.  INCOMPATIBILITY.
   845 
   846 * Theory syntax: some popular names (e.g. 'class', 'declaration',
   847 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
   848 quotes.
   849 
   850 * Theory loader: be more serious about observing the static theory
   851 header specifications (including optional directories), but not the
   852 accidental file locations of previously successful loads.  The strict
   853 update policy of former update_thy is now already performed by
   854 use_thy, so the former has been removed; use_thys updates several
   855 theories simultaneously, just as 'imports' within a theory header
   856 specification, but without merging the results.  Potential
   857 INCOMPATIBILITY: may need to refine theory headers and commands
   858 ROOT.ML which depend on load order.
   859 
   860 * Theory loader: optional support for content-based file
   861 identification, instead of the traditional scheme of full physical
   862 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
   863 (cf. the system manual).  The new scheme allows to work with
   864 non-finished theories in persistent session images, such that source
   865 files may be moved later on without requiring reloads.
   866 
   867 * Theory loader: old-style ML proof scripts being *attached* to a thy
   868 file (with the same base name as the theory) are considered a legacy
   869 feature, which will disappear eventually. Even now, the theory loader
   870 no longer maintains dependencies on such files.
   871 
   872 * Syntax: the scope for resolving ambiguities via type-inference is
   873 now limited to individual terms, instead of whole simultaneous
   874 specifications as before. This greatly reduces the complexity of the
   875 syntax module and improves flexibility by separating parsing and
   876 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
   877 'fixes' etc.) are required in rare situations.
   878 
   879 * Syntax: constants introduced by new-style packages ('definition',
   880 'abbreviation' etc.) are passed through the syntax module in
   881 ``authentic mode''. This means that associated mixfix annotations
   882 really stick to such constants, independently of potential name space
   883 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
   884 trees are represented slightly differently, may need to adapt syntax
   885 translations accordingly. Use CONST marker in 'translations' and
   886 @{const_syntax} antiquotation in 'parse_translation' etc.
   887 
   888 * Legacy goal package: reduced interface to the bare minimum required
   889 to keep existing proof scripts running.  Most other user-level
   890 functions are now part of the OldGoals structure, which is *not* open
   891 by default (consider isatool expandshort before open OldGoals).
   892 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
   893 these tend to cause confusion about the actual goal (!) context being
   894 used here, which is not necessarily the same as the_context().
   895 
   896 * Command 'find_theorems': supports "*" wild-card in "name:"
   897 criterion; "with_dups" option.  Certain ProofGeneral versions might
   898 support a specific search form (see ProofGeneral/CHANGES).
   899 
   900 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
   901 by default, which means that "prems" (and also "fixed variables") are
   902 suppressed from proof state output.  Note that the ProofGeneral
   903 settings mechanism allows to change and save options persistently, but
   904 older versions of Isabelle will fail to start up if a negative prems
   905 limit is imposed.
   906 
   907 * Local theory targets may be specified by non-nested blocks of
   908 ``context/locale/class ... begin'' followed by ``end''.  The body may
   909 contain definitions, theorems etc., including any derived mechanism
   910 that has been implemented on top of these primitives.  This concept
   911 generalizes the existing ``theorem (in ...)'' towards more versatility
   912 and scalability.
   913 
   914 * Proof General interface: proper undo of final 'end' command;
   915 discontinued Isabelle/classic mode (ML proof scripts).
   916 
   917 
   918 *** Document preparation ***
   919 
   920 * Added antiquotation @{theory name} which prints the given name,
   921 after checking that it refers to a valid ancestor theory in the
   922 current context.
   923 
   924 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   925 check the given source text as ML type/structure, printing verbatim.
   926 
   927 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   928 "c args == rhs" given in the current context.  (Any number of
   929 arguments may be given on the LHS.)
   930 
   931 
   932 *** Pure ***
   933 
   934 * The 'class' package offers a combination of axclass and locale to
   935 achieve Haskell-like type classes in Isabelle.  Definitions and
   936 theorems within a class context produce both relative results (with
   937 implicit parameters according to the locale context), and polymorphic
   938 constants with qualified polymorphism (according to the class
   939 context).  Within the body context of a 'class' target, a separate
   940 syntax layer ("user space type system") takes care of converting
   941 between global polymorphic consts and internal locale representation.
   942 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   943 "isatool doc classes" provides a tutorial.
   944 
   945 * Generic code generator framework allows to generate executable
   946 code for ML and Haskell (including Isabelle classes).  A short usage
   947 sketch:
   948 
   949     internal compilation:
   950         export_code <list of constants (term syntax)> in SML
   951     writing SML code to a file:
   952         export_code <list of constants (term syntax)> in SML <filename>
   953     writing OCaml code to a file:
   954         export_code <list of constants (term syntax)> in OCaml <filename>
   955     writing Haskell code to a bunch of files:
   956         export_code <list of constants (term syntax)> in Haskell <filename>
   957 
   958     evaluating closed propositions to True/False using code generation:
   959         method ``eval''
   960 
   961 Reasonable default setup of framework in HOL.
   962 
   963 Theorem attributs for selecting and transforming function equations theorems:
   964 
   965     [code fun]:        select a theorem as function equation for a specific constant
   966     [code fun del]:    deselect a theorem as function equation for a specific constant
   967     [code inline]:     select an equation theorem for unfolding (inlining) in place
   968     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   969 
   970 User-defined serializations (target in {SML, OCaml, Haskell}):
   971 
   972     code_const <and-list of constants (term syntax)>
   973       {(target) <and-list of const target syntax>}+
   974 
   975     code_type <and-list of type constructors>
   976       {(target) <and-list of type target syntax>}+
   977 
   978     code_instance <and-list of instances>
   979       {(target)}+
   980         where instance ::= <type constructor> :: <class>
   981 
   982     code_class <and_list of classes>
   983       {(target) <and-list of class target syntax>}+
   984         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   985 
   986 code_instance and code_class only are effective to target Haskell.
   987 
   988 For example usage see src/HOL/ex/Codegenerator.thy and
   989 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   990 generation from Isabelle/HOL theories is available via "isatool doc
   991 codegen".
   992 
   993 * Code generator: consts in 'consts_code' Isar commands are now
   994 referred to by usual term syntax (including optional type
   995 annotations).
   996 
   997 * Command 'no_translations' removes translation rules from theory
   998 syntax.
   999 
  1000 * Overloaded definitions are now actually checked for acyclic
  1001 dependencies.  The overloading scheme is slightly more general than
  1002 that of Haskell98, although Isabelle does not demand an exact
  1003 correspondence to type class and instance declarations.
  1004 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1005 exotic versions of overloading -- at the discretion of the user!
  1006 
  1007 Polymorphic constants are represented via type arguments, i.e. the
  1008 instantiation that matches an instance against the most general
  1009 declaration given in the signature.  For example, with the declaration
  1010 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1011 as c(nat).  Overloading is essentially simultaneous structural
  1012 recursion over such type arguments.  Incomplete specification patterns
  1013 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1014 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1015 Command 'print_theory' outputs the normalized system of recursive
  1016 equations, see section "definitions".
  1017 
  1018 * Configuration options are maintained within the theory or proof
  1019 context (with name and type bool/int/string), providing a very simple
  1020 interface to a poor-man's version of general context data.  Tools may
  1021 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1022 these values using Config.get etc.  Users may change options via an
  1023 associated attribute of the same name.  This form of context
  1024 declaration works particularly well with commands 'declare' or
  1025 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1026 very easy to avoid global references, which would not observe Isar
  1027 toplevel undo/redo and fail to work with multithreading.
  1028 
  1029 Various global ML references of Pure and HOL have been turned into
  1030 configuration options:
  1031 
  1032   Unify.search_bound		unify_search_bound
  1033   Unify.trace_bound		unify_trace_bound
  1034   Unify.trace_simp		unify_trace_simp
  1035   Unify.trace_types		unify_trace_types
  1036   Simplifier.simp_depth_limit	simp_depth_limit
  1037   Blast.depth_limit		blast_depth_limit
  1038   DatatypeProp.dtK		datatype_distinctness_limit
  1039   fast_arith_neq_limit  	fast_arith_neq_limit
  1040   fast_arith_split_limit	fast_arith_split_limit
  1041 
  1042 * Named collections of theorems may be easily installed as context
  1043 data using the functor NamedThmsFun (see also
  1044 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1045 attributes; there is also a toplevel print command.  This facility is
  1046 just a common case of general context data, which is the preferred way
  1047 for anything more complex than just a list of facts in canonical
  1048 order.
  1049 
  1050 * Isar: command 'declaration' augments a local theory by generic
  1051 declaration functions written in ML.  This enables arbitrary content
  1052 being added to the context, depending on a morphism that tells the
  1053 difference of the original declaration context wrt. the application
  1054 context encountered later on.
  1055 
  1056 * Isar: proper interfaces for simplification procedures.  Command
  1057 'simproc_setup' declares named simprocs (with match patterns, and body
  1058 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1059 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1060 
  1061 * Isar: an extra pair of brackets around attribute declarations
  1062 abbreviates a theorem reference involving an internal dummy fact,
  1063 which will be ignored later --- only the effect of the attribute on
  1064 the background context will persist.  This form of in-place
  1065 declarations is particularly useful with commands like 'declare' and
  1066 'using', for example ``have A using [[simproc a]] by simp''.
  1067 
  1068 * Isar: method "assumption" (and implicit closing of subproofs) now
  1069 takes simple non-atomic goal assumptions into account: after applying
  1070 an assumption as a rule the resulting subgoals are solved by atomic
  1071 assumption steps.  This is particularly useful to finish 'obtain'
  1072 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1073 without referring to the original premise "!!x. P x ==> thesis" in the
  1074 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1075 more permissive.
  1076 
  1077 * Isar: implicit use of prems from the Isar proof context is
  1078 considered a legacy feature.  Common applications like ``have A .''
  1079 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1080 referencing facts explicitly here improves readability and
  1081 maintainability of proof texts.
  1082 
  1083 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1084 the obtained context from the course of reasoning!  For example:
  1085 
  1086   assume "EX x y. A x & B y"   -- "any previous fact"
  1087   then guess x and y by clarify
  1088 
  1089 This technique is potentially adventurous, depending on the facts and
  1090 proof tools being involved here.
  1091 
  1092 * Isar: known facts from the proof context may be specified as literal
  1093 propositions, using ASCII back-quote syntax.  This works wherever
  1094 named facts used to be allowed so far, in proof commands, proof
  1095 methods, attributes etc.  Literal facts are retrieved from the context
  1096 according to unification of type and term parameters.  For example,
  1097 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1098 theorems in the current context, then these are valid literal facts:
  1099 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1100 
  1101 There is also a proof method "fact" which does the same composition
  1102 for explicit goal states, e.g. the following proof texts coincide with
  1103 certain special cases of literal facts:
  1104 
  1105   have "A" by fact                 ==  note `A`
  1106   have "A ==> B" by fact           ==  note `A ==> B`
  1107   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1108   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1109 
  1110 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1111 outer syntax.  Thus symbolic identifiers may be used without
  1112 additional white space in declarations like this: ``assume *: A''.
  1113 
  1114 * Isar: 'print_facts' prints all local facts of the current context,
  1115 both named and unnamed ones.
  1116 
  1117 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1118 
  1119   def x == "t" and y == "u"
  1120 
  1121 * Isar: added command 'unfolding', which is structurally similar to
  1122 'using', but affects both the goal state and facts by unfolding given
  1123 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1124 'unfolded' attribute may be replaced by first-class proof text.
  1125 
  1126 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1127 and command 'unfolding' now all support object-level equalities
  1128 (potentially conditional).  The underlying notion of rewrite rule is
  1129 analogous to the 'rule_format' attribute, but *not* that of the
  1130 Simplifier (which is usually more generous).
  1131 
  1132 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1133 premises of a theorem by n. Useful in conjunction with drule.
  1134 
  1135 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1136 method expression within a sandbox consisting of the first N
  1137 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1138 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1139 simplifies all new goals that emerge from applying rule foo to the
  1140 originally first one.
  1141 
  1142 * Isar: schematic goals are no longer restricted to higher-order
  1143 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1144 expected.
  1145 
  1146 * Isar: the conclusion of a long theorem statement is now either
  1147 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1148 (essentially a disjunction of cases with local parameters and
  1149 assumptions).  The latter allows to express general elimination rules
  1150 adequately; in this notation common elimination rules look like this:
  1151 
  1152   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1153     assumes "EX x. P x"
  1154     obtains x where "P x"
  1155 
  1156   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1157     assumes "A & B"
  1158     obtains A and B
  1159 
  1160   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1161     assumes "A | B"
  1162     obtains
  1163       A
  1164     | B
  1165 
  1166 The subsequent classical rules even refer to the formal "thesis"
  1167 explicitly:
  1168 
  1169   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1170     obtains "~ thesis"
  1171 
  1172   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1173     obtains "thesis ==> something"
  1174 
  1175 The actual proof of an 'obtains' statement is analogous to that of the
  1176 Isar proof element 'obtain', only that there may be several cases.
  1177 Optional case names may be specified in parentheses; these will be
  1178 available both in the present proof and as annotations in the
  1179 resulting rule, for later use with the 'cases' method (cf. attribute
  1180 case_names).
  1181 
  1182 * Isar: the assumptions of a long theorem statement are available as
  1183 "assms" fact in the proof context.  This is more appropriate than the
  1184 (historical) "prems", which refers to all assumptions of the current
  1185 context, including those from the target locale, proof body etc.
  1186 
  1187 * Isar: 'print_statement' prints theorems from the current theory or
  1188 proof context in long statement form, according to the syntax of a
  1189 top-level lemma.
  1190 
  1191 * Isar: 'obtain' takes an optional case name for the local context
  1192 introduction rule (default "that").
  1193 
  1194 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1195 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1196 to occur.
  1197 
  1198 * Pure: syntax "CONST name" produces a fully internalized constant
  1199 according to the current context.  This is particularly useful for
  1200 syntax translations that should refer to internal constant
  1201 representations independently of name spaces.
  1202 
  1203 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1204 instead of "FOO ". This allows multiple binder declarations to coexist
  1205 in the same context.  INCOMPATIBILITY.
  1206 
  1207 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1208 primitive that also works in a locale context (both for constants and
  1209 fixed variables). Type declaration and internal syntactic representation
  1210 of given constants retrieved from the context. Likewise, the
  1211 'no_notation' command allows to remove given syntax annotations from the
  1212 current context.
  1213 
  1214 * Isar/locales: new derived specification elements 'axiomatization',
  1215 'definition', 'abbreviation', which support type-inference, admit
  1216 object-level specifications (equality, equivalence).  See also the
  1217 isar-ref manual.  Examples:
  1218 
  1219   axiomatization
  1220     eq  (infix "===" 50) where
  1221     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1222 
  1223   definition "f x y = x + y + 1"
  1224   definition g where "g x = f x x"
  1225 
  1226   abbreviation
  1227     neq  (infix "=!=" 50) where
  1228     "x =!= y == ~ (x === y)"
  1229 
  1230 These specifications may be also used in a locale context.  Then the
  1231 constants being introduced depend on certain fixed parameters, and the
  1232 constant name is qualified by the locale base name.  An internal
  1233 abbreviation takes care for convenient input and output, making the
  1234 parameters implicit and using the original short name.  See also
  1235 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1236 entities from a monomorphic theory.
  1237 
  1238 Presently, abbreviations are only available 'in' a target locale, but
  1239 not inherited by general import expressions.  Also note that
  1240 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1241 'translations' in common applications.  The "no_abbrevs" print mode
  1242 prevents folding of abbreviations in term output.
  1243 
  1244 Concrete syntax is attached to specified constants in internal form,
  1245 independently of name spaces.  The parse tree representation is
  1246 slightly different -- use 'notation' instead of raw 'syntax', and
  1247 'translations' with explicit "CONST" markup to accommodate this.
  1248 
  1249 * Pure/Isar: unified syntax for new-style specification mechanisms
  1250 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1251 full type inference and dummy patterns ("_").  For example:
  1252 
  1253   definition "K x _ = x"
  1254 
  1255   inductive conj for A B
  1256   where "A ==> B ==> conj A B"
  1257 
  1258 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1259 the current context.  Print mode "no_abbrevs" prevents inversion of
  1260 abbreviations on output.
  1261 
  1262 * Isar/locales: improved parameter handling: use of locales "var" and
  1263 "struct" no longer necessary; - parameter renamings are no longer
  1264 required to be injective.  For example, this allows to define
  1265 endomorphisms as locale endom = homom mult mult h.
  1266 
  1267 * Isar/locales: changed the way locales with predicates are defined.
  1268 Instead of accumulating the specification, the imported expression is
  1269 now an interpretation.  INCOMPATIBILITY: different normal form of
  1270 locale expressions.  In particular, in interpretations of locales with
  1271 predicates, goals repesenting already interpreted fragments are not
  1272 removed automatically.  Use methods `intro_locales' and
  1273 `unfold_locales'; see below.
  1274 
  1275 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1276 provide backward reasoning on locales predicates.  The methods are
  1277 aware of interpretations and discharge corresponding goals.
  1278 `intro_locales' is less aggressive then `unfold_locales' and does not
  1279 unfold predicates to assumptions.
  1280 
  1281 * Isar/locales: the order in which locale fragments are accumulated
  1282 has changed.  This enables to override declarations from fragments due
  1283 to interpretations -- for example, unwanted simp rules.
  1284 
  1285 * Isar/locales: interpretation in theories and proof contexts has been
  1286 extended.  One may now specify (and prove) equations, which are
  1287 unfolded in interpreted theorems.  This is useful for replacing
  1288 defined concepts (constants depending on locale parameters) by
  1289 concepts already existing in the target context.  Example:
  1290 
  1291   interpretation partial_order ["op <= :: [int, int] => bool"]
  1292     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1293 
  1294 Typically, the constant `partial_order.less' is created by a
  1295 definition specification element in the context of locale
  1296 partial_order.
  1297 
  1298 * Method "induct": improved internal context management to support
  1299 local fixes and defines on-the-fly. Thus explicit meta-level
  1300 connectives !!  and ==> are rarely required anymore in inductive goals
  1301 (using object-logic connectives for this purpose has been long
  1302 obsolete anyway). Common proof patterns are explained in
  1303 src/HOL/Induct/Common_Patterns.thy, see also
  1304 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1305 examples.
  1306 
  1307 * Method "induct": improved handling of simultaneous goals. Instead of
  1308 introducing object-level conjunction, the statement is now split into
  1309 several conclusions, while the corresponding symbolic cases are nested
  1310 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1311 see src/HOL/Induct/Common_Patterns.thy, for example.
  1312 
  1313 * Method "induct": mutual induction rules are now specified as a list
  1314 of rule sharing the same induction cases. HOL packages usually provide
  1315 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1316 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1317 mutual induction rules differently, i.e. like this:
  1318 
  1319   (induct rule: foo_bar.inducts)
  1320   (induct set: foo bar)
  1321   (induct pred: foo bar)
  1322   (induct type: foo bar)
  1323 
  1324 The ML function ProjectRule.projections turns old-style rules into the
  1325 new format.
  1326 
  1327 * Method "coinduct": dual of induction, see
  1328 src/HOL/Library/Coinductive_List.thy for various examples.
  1329 
  1330 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1331 considered a legacy feature.
  1332 
  1333 * Attribute "symmetric" produces result with standardized schematic
  1334 variables (index 0).  Potential INCOMPATIBILITY.
  1335 
  1336 * Simplifier: by default the simplifier trace only shows top level
  1337 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1338 default. Thus there is less danger of being flooded by the trace. The
  1339 trace indicates where parts have been suppressed.
  1340   
  1341 * Provers/classical: removed obsolete classical version of elim_format
  1342 attribute; classical elim/dest rules are now treated uniformly when
  1343 manipulating the claset.
  1344 
  1345 * Provers/classical: stricter checks to ensure that supplied intro,
  1346 dest and elim rules are well-formed; dest and elim rules must have at
  1347 least one premise.
  1348 
  1349 * Provers/classical: attributes dest/elim/intro take an optional
  1350 weight argument for the rule (just as the Pure versions).  Weights are
  1351 ignored by automated tools, but determine the search order of single
  1352 rule steps.
  1353 
  1354 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1355 where the body does not mention the bound variable.  Note that dummy
  1356 patterns implicitly depend on their context of bounds, which makes
  1357 "{_. _}" match any set comprehension as expected.  Potential
  1358 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1359 constant "_idtdummy" in the binding position.
  1360 
  1361 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1362 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1363 for example "A -> B" => "Pi A (%_. B)".
  1364 
  1365 * Pure: 'class_deps' command visualizes the subclass relation, using
  1366 the graph browser tool.
  1367 
  1368 * Pure: 'print_theory' now suppresses certain internal declarations by
  1369 default; use '!' option for full details.
  1370 
  1371 
  1372 *** HOL ***
  1373 
  1374 * Method "metis" proves goals by applying the Metis general-purpose
  1375 resolution prover (see also http://gilith.com/software/metis/).
  1376 Examples are in the directory MetisExamples.  WARNING: the
  1377 Isabelle/HOL-Metis integration does not yet work properly with
  1378 multi-threading.
  1379   
  1380 * Command 'sledgehammer' invokes external automatic theorem provers as
  1381 background processes.  It generates calls to the "metis" method if
  1382 successful. These can be pasted into the proof.  Users do not have to
  1383 wait for the automatic provers to return.  WARNING: does not really
  1384 work with multi-threading.
  1385 
  1386 * New "auto_quickcheck" feature tests outermost goal statements for
  1387 potential counter-examples.  Controlled by ML references
  1388 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1389 5000 milliseconds).  Fails silently if statements is outside of
  1390 executable fragment, or any other codgenerator problem occurs.
  1391 
  1392 * New constant "undefined" with axiom "undefined x = undefined".
  1393 
  1394 * Added class "HOL.eq", allowing for code generation with polymorphic
  1395 equality.
  1396 
  1397 * Some renaming of class constants due to canonical name prefixing in
  1398 the new 'class' package:
  1399 
  1400     HOL.abs ~> HOL.abs_class.abs
  1401     HOL.divide ~> HOL.divide_class.divide
  1402     0 ~> HOL.zero_class.zero
  1403     1 ~> HOL.one_class.one
  1404     op + ~> HOL.plus_class.plus
  1405     op - ~> HOL.minus_class.minus
  1406     uminus ~> HOL.minus_class.uminus
  1407     op * ~> HOL.times_class.times
  1408     op < ~> HOL.ord_class.less
  1409     op <= > HOL.ord_class.less_eq
  1410     Nat.power ~> Power.power_class.power
  1411     Nat.size ~> Nat.size_class.size
  1412     Numeral.number_of ~> Numeral.number_class.number_of
  1413     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1414     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1415     Orderings.min ~> Orderings.ord_class.min
  1416     Orderings.max ~> Orderings.ord_class.max
  1417     Divides.op div ~> Divides.div_class.div
  1418     Divides.op mod ~> Divides.div_class.mod
  1419     Divides.op dvd ~> Divides.div_class.dvd
  1420 
  1421 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1422 
  1423 a) User-defined constants using any of the names "plus", "minus",
  1424 "times", "less" or "less_eq". The standard syntax translations for
  1425 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1426 names.
  1427 
  1428 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1429 INCOMPATIBILITY: use more specific names.
  1430 
  1431 c) Permutative equations (e.g. "a + b = b + a")
  1432 Since the change of names also changes the order of terms, permutative
  1433 rewrite rules may get applied in a different order. Experience shows
  1434 that this is rarely the case (only two adaptions in the whole Isabelle
  1435 distribution).  INCOMPATIBILITY: rewrite proofs
  1436 
  1437 d) ML code directly refering to constant names
  1438 This in general only affects hand-written proof tactics, simprocs and
  1439 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1440 Consider using @{const_name} antiquotation.
  1441 
  1442 * New class "default" with associated constant "default".
  1443 
  1444 * Function "sgn" is now overloaded and available on int, real, complex
  1445 (and other numeric types), using class "sgn".  Two possible defs of
  1446 sgn are given as equational assumptions in the classes sgn_if and
  1447 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1448 INCOMPATIBILITY.
  1449 
  1450 * Locale "partial_order" now unified with class "order" (cf. theory
  1451 Orderings), added parameter "less".  INCOMPATIBILITY.
  1452 
  1453 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1454 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1455 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1456 
  1457 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1458 changed order of proof goals in instance proofs.
  1459 
  1460 * The transitivity reasoner for partial and linear orders is set up
  1461 for classes "order" and "linorder".  Instances of the reasoner are available
  1462 in all contexts importing or interpreting the corresponding locales.
  1463 Method "order" invokes the reasoner separately; the reasoner
  1464 is also integrated with the Simplifier as a solver.  Diagnostic
  1465 command 'print_orders' shows the available instances of the reasoner
  1466 in the current context.
  1467 
  1468 * Localized monotonicity predicate in theory "Orderings"; integrated
  1469 lemmas max_of_mono and min_of_mono with this predicate.
  1470 INCOMPATIBILITY.
  1471 
  1472 * Formulation of theorem "dense" changed slightly due to integration
  1473 with new class dense_linear_order.
  1474 
  1475 * Uniform lattice theory development in HOL.
  1476 
  1477     constants "meet" and "join" now named "inf" and "sup"
  1478     constant "Meet" now named "Inf"
  1479 
  1480     classes "meet_semilorder" and "join_semilorder" now named
  1481       "lower_semilattice" and "upper_semilattice"
  1482     class "lorder" now named "lattice"
  1483     class "comp_lat" now named "complete_lattice"
  1484 
  1485     Instantiation of lattice classes allows explicit definitions
  1486     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1487 
  1488   INCOMPATIBILITY.  Theorem renames:
  1489 
  1490     meet_left_le            ~> inf_le1
  1491     meet_right_le           ~> inf_le2
  1492     join_left_le            ~> sup_ge1
  1493     join_right_le           ~> sup_ge2
  1494     meet_join_le            ~> inf_sup_ord
  1495     le_meetI                ~> le_infI
  1496     join_leI                ~> le_supI
  1497     le_meet                 ~> le_inf_iff
  1498     le_join                 ~> ge_sup_conv
  1499     meet_idempotent         ~> inf_idem
  1500     join_idempotent         ~> sup_idem
  1501     meet_comm               ~> inf_commute
  1502     join_comm               ~> sup_commute
  1503     meet_leI1               ~> le_infI1
  1504     meet_leI2               ~> le_infI2
  1505     le_joinI1               ~> le_supI1
  1506     le_joinI2               ~> le_supI2
  1507     meet_assoc              ~> inf_assoc
  1508     join_assoc              ~> sup_assoc
  1509     meet_left_comm          ~> inf_left_commute
  1510     meet_left_idempotent    ~> inf_left_idem
  1511     join_left_comm          ~> sup_left_commute
  1512     join_left_idempotent    ~> sup_left_idem
  1513     meet_aci                ~> inf_aci
  1514     join_aci                ~> sup_aci
  1515     le_def_meet             ~> le_iff_inf
  1516     le_def_join             ~> le_iff_sup
  1517     join_absorp2            ~> sup_absorb2
  1518     join_absorp1            ~> sup_absorb1
  1519     meet_absorp1            ~> inf_absorb1
  1520     meet_absorp2            ~> inf_absorb2
  1521     meet_join_absorp        ~> inf_sup_absorb
  1522     join_meet_absorp        ~> sup_inf_absorb
  1523     distrib_join_le         ~> distrib_sup_le
  1524     distrib_meet_le         ~> distrib_inf_le
  1525 
  1526     add_meet_distrib_left   ~> add_inf_distrib_left
  1527     add_join_distrib_left   ~> add_sup_distrib_left
  1528     is_join_neg_meet        ~> is_join_neg_inf
  1529     is_meet_neg_join        ~> is_meet_neg_sup
  1530     add_meet_distrib_right  ~> add_inf_distrib_right
  1531     add_join_distrib_right  ~> add_sup_distrib_right
  1532     add_meet_join_distribs  ~> add_sup_inf_distribs
  1533     join_eq_neg_meet        ~> sup_eq_neg_inf
  1534     meet_eq_neg_join        ~> inf_eq_neg_sup
  1535     add_eq_meet_join        ~> add_eq_inf_sup
  1536     meet_0_imp_0            ~> inf_0_imp_0
  1537     join_0_imp_0            ~> sup_0_imp_0
  1538     meet_0_eq_0             ~> inf_0_eq_0
  1539     join_0_eq_0             ~> sup_0_eq_0
  1540     neg_meet_eq_join        ~> neg_inf_eq_sup
  1541     neg_join_eq_meet        ~> neg_sup_eq_inf
  1542     join_eq_if              ~> sup_eq_if
  1543 
  1544     mono_meet               ~> mono_inf
  1545     mono_join               ~> mono_sup
  1546     meet_bool_eq            ~> inf_bool_eq
  1547     join_bool_eq            ~> sup_bool_eq
  1548     meet_fun_eq             ~> inf_fun_eq
  1549     join_fun_eq             ~> sup_fun_eq
  1550     meet_set_eq             ~> inf_set_eq
  1551     join_set_eq             ~> sup_set_eq
  1552     meet1_iff               ~> inf1_iff
  1553     meet2_iff               ~> inf2_iff
  1554     meet1I                  ~> inf1I
  1555     meet2I                  ~> inf2I
  1556     meet1D1                 ~> inf1D1
  1557     meet2D1                 ~> inf2D1
  1558     meet1D2                 ~> inf1D2
  1559     meet2D2                 ~> inf2D2
  1560     meet1E                  ~> inf1E
  1561     meet2E                  ~> inf2E
  1562     join1_iff               ~> sup1_iff
  1563     join2_iff               ~> sup2_iff
  1564     join1I1                 ~> sup1I1
  1565     join2I1                 ~> sup2I1
  1566     join1I1                 ~> sup1I1
  1567     join2I2                 ~> sup1I2
  1568     join1CI                 ~> sup1CI
  1569     join2CI                 ~> sup2CI
  1570     join1E                  ~> sup1E
  1571     join2E                  ~> sup2E
  1572 
  1573     is_meet_Meet            ~> is_meet_Inf
  1574     Meet_bool_def           ~> Inf_bool_def
  1575     Meet_fun_def            ~> Inf_fun_def
  1576     Meet_greatest           ~> Inf_greatest
  1577     Meet_lower              ~> Inf_lower
  1578     Meet_set_def            ~> Inf_set_def
  1579 
  1580     Sup_def                 ~> Sup_Inf
  1581     Sup_bool_eq             ~> Sup_bool_def
  1582     Sup_fun_eq              ~> Sup_fun_def
  1583     Sup_set_eq              ~> Sup_set_def
  1584 
  1585     listsp_meetI            ~> listsp_infI
  1586     listsp_meet_eq          ~> listsp_inf_eq
  1587 
  1588     meet_min                ~> inf_min
  1589     join_max                ~> sup_max
  1590 
  1591 * Added syntactic class "size"; overloaded constant "size" now has
  1592 type "'a::size ==> bool"
  1593 
  1594 * Internal reorganisation of `size' of datatypes: size theorems
  1595 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1596 simplification rules by default!); theorems "prod.size" now named
  1597 "*.size".
  1598 
  1599 * Class "div" now inherits from class "times" rather than "type".
  1600 INCOMPATIBILITY.
  1601 
  1602 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1603 Linorder etc.  have disappeared; operations defined in terms of
  1604 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1605 
  1606 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1607 
  1608 * HOL-Word: New extensive library and type for generic, fixed size
  1609 machine words, with arithemtic, bit-wise, shifting and rotating
  1610 operations, reflection into int, nat, and bool lists, automation for
  1611 linear arithmetic (by automatic reflection into nat or int), including
  1612 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1613 arithmetic type classes, supporting automatic simplification of
  1614 numerals on all operations.
  1615 
  1616 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1617 
  1618 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1619 
  1620 * Code generator library theories:
  1621   - Code_Integer represents HOL integers by big integer literals in target
  1622     languages.
  1623   - Code_Char represents HOL characters by character literals in target
  1624     languages.
  1625   - Code_Char_chr like Code_Char, but also offers treatment of character
  1626     codes; includes Code_Integer.
  1627   - Executable_Set allows to generate code for finite sets using lists.
  1628   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1629     denominator).
  1630   - Executable_Real implements a subset of real numbers, namly those
  1631     representable by rational numbers.
  1632   - Efficient_Nat implements natural numbers by integers, which in general will
  1633     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1634     includes Code_Integer.
  1635   - Code_Index provides an additional datatype index which is mapped to
  1636     target-language built-in integers.
  1637   - Code_Message provides an additional datatype message_string which is isomorphic to
  1638     strings; messages are mapped to target-language strings.
  1639 
  1640 * New package for inductive predicates
  1641 
  1642   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1643 
  1644     inductive
  1645       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1646       for z_1 :: U_1 and ... and z_n :: U_m
  1647     where
  1648       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1649     | ...
  1650 
  1651   with full support for type-inference, rather than
  1652 
  1653     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1654 
  1655     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1656     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1657 
  1658     inductive "s z_1 ... z_m"
  1659     intros
  1660       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1661       ...
  1662 
  1663   For backward compatibility, there is a wrapper allowing inductive
  1664   sets to be defined with the new package via
  1665 
  1666     inductive_set
  1667       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1668       for z_1 :: U_1 and ... and z_n :: U_m
  1669     where
  1670       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1671     | ...
  1672 
  1673   or
  1674 
  1675     inductive_set
  1676       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1677       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1678       for z_1 :: U_1 and ... and z_n :: U_m
  1679     where
  1680       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1681     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1682     | ...
  1683 
  1684   if the additional syntax "p ..." is required.
  1685 
  1686   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1687   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1688 
  1689   INCOMPATIBILITIES:
  1690 
  1691   - Since declaration and definition of inductive sets or predicates
  1692     is no longer separated, abbreviations involving the newly
  1693     introduced sets or predicates must be specified together with the
  1694     introduction rules after the 'where' keyword (see above), rather
  1695     than before the actual inductive definition.
  1696 
  1697   - The variables in induction and elimination rules are now
  1698     quantified in the order of their occurrence in the introduction
  1699     rules, rather than in alphabetical order. Since this may break
  1700     some proofs, these proofs either have to be repaired, e.g. by
  1701     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1702     statements of the form
  1703 
  1704       case (rule_i a_i_1 ... a_i_{k_i})
  1705 
  1706     or the old order of quantification has to be restored by explicitly adding
  1707     meta-level quantifiers in the introduction rules, i.e.
  1708 
  1709       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  1710 
  1711   - The format of the elimination rules is now
  1712 
  1713       p z_1 ... z_m x_1 ... x_n ==>
  1714         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1715         ==> ... ==> P
  1716 
  1717     for predicates and
  1718 
  1719       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1720         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1721         ==> ... ==> P
  1722 
  1723     for sets rather than
  1724 
  1725       x : s z_1 ... z_m ==>
  1726         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1727         ==> ... ==> P
  1728 
  1729     This may require terms in goals to be expanded to n-tuples
  1730     (e.g. using case_tac or simplification with the split_paired_all
  1731     rule) before the above elimination rule is applicable.
  1732 
  1733   - The elimination or case analysis rules for (mutually) inductive
  1734     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1735     list of rules "p_1_..._p_k.elims" is no longer available.
  1736 
  1737 * New package "function"/"fun" for general recursive functions,
  1738 supporting mutual and nested recursion, definitions in local contexts,
  1739 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1740 for small examples, and the separate tutorial on the function
  1741 package. The old recdef "package" is still available as before, but
  1742 users are encouraged to use the new package.
  1743 
  1744 * Method "lexicographic_order" automatically synthesizes termination
  1745 relations as lexicographic combinations of size measures. 
  1746 
  1747 * Case-expressions allow arbitrary constructor-patterns (including
  1748 "_") and take their order into account, like in functional
  1749 programming.  Internally, this is translated into nested
  1750 case-expressions; missing cases are added and mapped to the predefined
  1751 constant "undefined". In complicated cases printing may no longer show
  1752 the original input but the internal form. Lambda-abstractions allow
  1753 the same form of pattern matching: "% pat1 => e1 | ..." is an
  1754 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  1755 variable.
  1756 
  1757 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  1758 is an abbreviation for "of_nat :: nat => int". The simplification
  1759 rules for "of_nat" have been changed to work like "int" did
  1760 previously.  Potential INCOMPATIBILITY:
  1761   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  1762   - of_nat_diff and of_nat_mult are no longer default simp rules
  1763 
  1764 * Method "algebra" solves polynomial equations over (semi)rings using
  1765 Groebner bases. The (semi)ring structure is defined by locales and the
  1766 tool setup depends on that generic context. Installing the method for
  1767 a specific type involves instantiating the locale and possibly adding
  1768 declarations for computation on the coefficients.  The method is
  1769 already instantiated for natural numbers and for the axiomatic class
  1770 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  1771 CALCULEMUS 2007 for the general principles underlying this
  1772 architecture of context-aware proof-tools.
  1773 
  1774 * Method "ferrack" implements quantifier elimination over
  1775 special-purpose dense linear orders using locales (analogous to
  1776 "algebra"). The method is already installed for class
  1777 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  1778 rat, etc.
  1779 
  1780 * Former constant "List.op @" now named "List.append".  Use ML
  1781 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  1782 circumvent possible incompatibilities when working on ML level.
  1783 
  1784 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1785 
  1786 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1787 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1788 
  1789 * New syntax for Haskell-like list comprehension (input only), eg.
  1790 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1791 
  1792 * The special syntax for function "filter" has changed from [x :
  1793 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1794 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1795 
  1796 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1797 defined on nat only, as an abbreviation for [a..<Suc b]
  1798 INCOMPATIBILITY.
  1799 
  1800 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1801 
  1802 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1803 
  1804 * New lemma collection field_simps (an extension of ring_simps) for
  1805 manipulating (in)equations involving division. Multiplies with all
  1806 denominators that can be proved to be non-zero (in equations) or
  1807 positive/negative (in inequations).
  1808 
  1809 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1810 have been improved and renamed to ring_simps, group_simps and
  1811 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1812 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1813 
  1814 * Theory Library/Commutative_Ring: switched from recdef to function
  1815 package; constants add, mul, pow now curried.  Infix syntax for
  1816 algebraic operations.
  1817 
  1818 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1819 INCOMPATIBILITY.
  1820 
  1821 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1822 INCOMPATIBILITY.
  1823 
  1824 * HOL/records: generalised field-update to take a function on the
  1825 field rather than the new value: r(|A := x|) is translated to A_update
  1826 (K x) r The K-combinator that is internally used is called K_record.
  1827 INCOMPATIBILITY: Usage of the plain update functions has to be
  1828 adapted.
  1829  
  1830 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1831 * x = 0, which are required for a semiring.  Richer structures do not
  1832 inherit from semiring_0 anymore, because this property is a theorem
  1833 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1834 there is more to prove, but this is mostly trivial.
  1835 
  1836 * Class "recpower" is generalized to arbitrary monoids, not just
  1837 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1838 commutativity or semiring properties additionally.
  1839 
  1840 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1841 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1842 better use 'abbreviation'.
  1843 
  1844 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1845 
  1846 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1847 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1848 significant changes for setting up numeral syntax for types:
  1849   - New constants Numeral.pred and Numeral.succ instead
  1850       of former Numeral.bin_pred and Numeral.bin_succ.
  1851   - Use integer operations instead of bin_add, bin_mult and so on.
  1852   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1853   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1854 
  1855 See src/HOL/Integ/IntArith.thy for an example setup.
  1856 
  1857 * Command 'normal_form' computes the normal form of a term that may
  1858 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1859 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1860 heavy-duty computations because the functions are compiled to ML
  1861 first.  Correspondingly, a method "normalization" is provided.  See
  1862 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1863 
  1864 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1865 25 like -->); output depends on the "iff" print_mode, the default is
  1866 "A = B" (with priority 50).
  1867 
  1868 * Relations less (<) and less_eq (<=) are also available on type bool.
  1869 Modified syntax to disallow nesting without explicit parentheses,
  1870 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1871 INCOMPATIBILITY.
  1872 
  1873 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1874 
  1875 * Relation composition operator "op O" now has precedence 75 and binds
  1876 stronger than union and intersection. INCOMPATIBILITY.
  1877 
  1878 * The old set interval syntax "{m..n(}" (and relatives) has been
  1879 removed.  Use "{m..<n}" (and relatives) instead.
  1880 
  1881 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1882 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1883 ``declare [[simproc del: neq]]''.
  1884 
  1885 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1886 True/False.
  1887 
  1888 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1889 
  1890 * Theorem setsum_mult renamed to setsum_right_distrib.
  1891 
  1892 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1893 ``rule'' method.
  1894 
  1895 * Reimplemented methods "sat" and "satx", with several improvements:
  1896 goals no longer need to be stated as "<prems> ==> False", equivalences
  1897 (i.e. "=" on type bool) are handled, variable names of the form
  1898 "lit_<n>" are no longer reserved, significant speedup.
  1899 
  1900 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1901 zChaff is still supported as well.
  1902 
  1903 * 'inductive' and 'datatype': provide projections of mutual rules,
  1904 bundled as foo_bar.inducts;
  1905 
  1906 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1907 Library.
  1908 
  1909 * Library: moved theory Accessible_Part to main HOL.
  1910 
  1911 * Library: added theory Coinductive_List of potentially infinite lists
  1912 as greatest fixed-point.
  1913 
  1914 * Library: added theory AssocList which implements (finite) maps as
  1915 association lists.
  1916 
  1917 * Method "evaluation" solves goals (i.e. a boolean expression)
  1918 efficiently by compiling it to ML.  The goal is "proved" (via an
  1919 oracle) if it evaluates to True.
  1920 
  1921 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1922 also when invoked by the simplifier.  This results in the Simplifier
  1923 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1924 Configuration option fast_arith_split_limit=0 recovers the old
  1925 behavior.
  1926 
  1927 * Support for hex (0x20) and binary (0b1001) numerals.
  1928 
  1929 * New method: reify eqs (t), where eqs are equations for an
  1930 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1931 parameter, computes a term s::'b and a list xs::'a list and proves the
  1932 theorem I xs s = t. This is also known as reification or quoting. The
  1933 resulting theorem is applied to the subgoal to substitute t with I xs
  1934 s.  If t is omitted, the subgoal itself is reified.
  1935 
  1936 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1937 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1938 where f is supposed to be a computable function (in the sense of code
  1939 generattion). The method uses reify to compute s and xs as above then
  1940 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1941 r and finally gets the theorem t = r, which is again applied to the
  1942 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1943 
  1944 * Reflection: Automatic reification now handels binding, an example is
  1945 available in src/HOL/ex/ReflectionEx.thy
  1946 
  1947 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  1948 command 'statespace' that is similar to 'record', but introduces an
  1949 abstract specification based on the locale infrastructure instead of
  1950 HOL types.  This leads to extra flexibility in composing state spaces,
  1951 in particular multiple inheritance and renaming of components.
  1952 
  1953 
  1954 *** HOL-Complex ***
  1955 
  1956 * Hyperreal: Functions root and sqrt are now defined on negative real
  1957 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1958 Nonnegativity side conditions have been removed from many lemmas, so
  1959 that more subgoals may now be solved by simplification; potential
  1960 INCOMPATIBILITY.
  1961 
  1962 * Real: new type classes formalize real normed vector spaces and
  1963 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1964 and norm :: 'a => real.
  1965 
  1966 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1967 reals into other types. The overloaded constant Reals :: 'a set is now
  1968 defined as range of_real; potential INCOMPATIBILITY.
  1969 
  1970 * Real: proper support for ML code generation, including 'quickcheck'.
  1971 Reals are implemented as arbitrary precision rationals.
  1972 
  1973 * Hyperreal: Several constants that previously worked only for the
  1974 reals have been generalized, so they now work over arbitrary vector
  1975 spaces. Type annotations may need to be added in some cases; potential
  1976 INCOMPATIBILITY.
  1977 
  1978   Infinitesimal  :: ('a::real_normed_vector) star set
  1979   HFinite        :: ('a::real_normed_vector) star set
  1980   HInfinite      :: ('a::real_normed_vector) star set
  1981   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1982   monad          :: ('a::real_normed_vector) star => 'a star set
  1983   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1984   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1985   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1986   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1987   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1988   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1989   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1990   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1991   sgn            :: 'a::real_normed_vector => 'a
  1992   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1993 
  1994 * Complex: Some complex-specific constants are now abbreviations for
  1995 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1996 hnorm.  Other constants have been entirely removed in favor of the
  1997 polymorphic versions (INCOMPATIBILITY):
  1998 
  1999   approx        <-- capprox
  2000   HFinite       <-- CFinite
  2001   HInfinite     <-- CInfinite
  2002   Infinitesimal <-- CInfinitesimal
  2003   monad         <-- cmonad
  2004   galaxy        <-- cgalaxy
  2005   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2006   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2007   (ns)deriv     <-- (ns)cderiv
  2008 
  2009 
  2010 *** HOL-Algebra ***
  2011 
  2012 * Formalisation of ideals and the quotient construction over rings.
  2013 
  2014 * Order and lattice theory no longer based on records.
  2015 INCOMPATIBILITY.
  2016 
  2017 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2018 greatest_closed.  INCOMPATIBILITY.
  2019 
  2020 * Method algebra is now set up via an attribute.  For examples see
  2021 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2022 of algebraic structures.
  2023 
  2024 * Renamed theory CRing to Ring.
  2025 
  2026 
  2027 *** HOL-Nominal ***
  2028 
  2029 * Substantial, yet incomplete support for nominal datatypes (binding
  2030 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2031 src/HOL/Nominal/Examples.  Prospective users should consult
  2032 http://isabelle.in.tum.de/nominal/
  2033 
  2034 
  2035 *** ML ***
  2036 
  2037 * ML basics: just one true type int, which coincides with IntInf.int
  2038 (even on SML/NJ).
  2039 
  2040 * ML within Isar: antiquotations allow to embed statically-checked
  2041 formal entities in the source, referring to the context available at
  2042 compile-time.  For example:
  2043 
  2044 ML {* @{sort "{zero,one}"} *}
  2045 ML {* @{typ "'a => 'b"} *}
  2046 ML {* @{term "%x. x"} *}
  2047 ML {* @{prop "x == y"} *}
  2048 ML {* @{ctyp "'a => 'b"} *}
  2049 ML {* @{cterm "%x. x"} *}
  2050 ML {* @{cprop "x == y"} *}
  2051 ML {* @{thm asm_rl} *}
  2052 ML {* @{thms asm_rl} *}
  2053 ML {* @{type_name c} *}
  2054 ML {* @{type_syntax c} *}
  2055 ML {* @{const_name c} *}
  2056 ML {* @{const_syntax c} *}
  2057 ML {* @{context} *}
  2058 ML {* @{theory} *}
  2059 ML {* @{theory Pure} *}
  2060 ML {* @{theory_ref} *}
  2061 ML {* @{theory_ref Pure} *}
  2062 ML {* @{simpset} *}
  2063 ML {* @{claset} *}
  2064 ML {* @{clasimpset} *}
  2065 
  2066 The same works for sources being ``used'' within an Isar context.
  2067 
  2068 * ML in Isar: improved error reporting; extra verbosity with
  2069 ML_Context.trace enabled.
  2070 
  2071 * Pure/General/table.ML: the join operations now works via exceptions
  2072 DUP/SAME instead of type option. This is simpler in simple cases, and
  2073 admits slightly more efficient complex applications.
  2074 
  2075 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2076 use Context.generic instead of just theory.
  2077 
  2078 * Pure: datatype Context.generic joins theory/Proof.context and
  2079 provides some facilities for code that works in either kind of
  2080 context, notably GenericDataFun for uniform theory and proof data.
  2081 
  2082 * Pure: simplified internal attribute type, which is now always
  2083 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2084 local (Proof.context) attributes have been discontinued, while
  2085 minimizing code duplication. Thm.rule_attribute and
  2086 Thm.declaration_attribute build canonical attributes; see also structure
  2087 Context for further operations on Context.generic, notably
  2088 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2089 declarations and definitions.
  2090 
  2091 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2092 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2093 init only required for impure data. INCOMPATIBILITY: empty really need
  2094 to be empty (no dependencies on theory content!)
  2095 
  2096 * Pure/kernel: consts certification ignores sort constraints given in
  2097 signature declarations. (This information is not relevant to the
  2098 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2099 potential INCOMPATIBILITY.
  2100 
  2101 * Pure: axiomatic type classes are now purely definitional, with
  2102 explicit proofs of class axioms and super class relations performed
  2103 internally. See Pure/axclass.ML for the main internal interfaces --
  2104 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2105 AxClass.axiomatize_class/classrel/arity supersede
  2106 Sign.add_classes/classrel/arities.
  2107 
  2108 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2109 global/local versions on theory vs. Proof.context have been
  2110 discontinued; Attrib.syntax and Method.syntax have been adapted
  2111 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2112 attributes, methods, etc.
  2113 
  2114 * Pure: several functions of signature "... -> theory -> theory * ..."
  2115 have been reoriented to "... -> theory -> ... * theory" in order to
  2116 allow natural usage in combination with the ||>, ||>>, |-> and
  2117 fold_map combinators.
  2118 
  2119 * Pure: official theorem names (closed derivations) and additional
  2120 comments (tags) are now strictly separate.  Name hints -- which are
  2121 maintained as tags -- may be attached any time without affecting the
  2122 derivation.
  2123 
  2124 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2125 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2126 achieve the old behaviour.
  2127 
  2128 * Pure: the "Goal" constant is now called "prop", supporting a
  2129 slightly more general idea of ``protecting'' meta-level rule
  2130 statements.
  2131 
  2132 * Pure: Logic.(un)varify only works in a global context, which is now
  2133 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2134 Logic.legacy_(un)varify as temporary workaround.
  2135 
  2136 * Pure: structure Name provides scalable operations for generating
  2137 internal variable names, notably Name.variants etc.  This replaces
  2138 some popular functions from term.ML:
  2139 
  2140   Term.variant		->  Name.variant
  2141   Term.variantlist	->  Name.variant_list
  2142   Term.invent_names	->  Name.invent_list
  2143 
  2144 Note that low-level renaming rarely occurs in new code -- operations
  2145 from structure Variable are used instead (see below).
  2146 
  2147 * Pure: structure Variable provides fundamental operations for proper
  2148 treatment of fixed/schematic variables in a context.  For example,
  2149 Variable.import introduces fixes for schematics of given facts and
  2150 Variable.export reverses the effect (up to renaming) -- this replaces
  2151 various freeze_thaw operations.
  2152 
  2153 * Pure: structure Goal provides simple interfaces for
  2154 init/conclude/finish and tactical prove operations (replacing former
  2155 Tactic.prove).  Goal.prove is the canonical way to prove results
  2156 within a given context; Goal.prove_global is a degraded version for
  2157 theory level goals, including a global Drule.standard.  Note that
  2158 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2159 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2160 in a locale context).
  2161 
  2162 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2163 and type checking (Syntax.check_term etc.), with common combinations
  2164 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2165 which are considered legacy and await removal.
  2166 
  2167 * Pure/Syntax: generic interfaces for type unchecking
  2168 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2169 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2170 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2171 available for convenience, but refer to the very same operations using
  2172 a mere theory instead of a full context.
  2173 
  2174 * Isar: simplified treatment of user-level errors, using exception
  2175 ERROR of string uniformly.  Function error now merely raises ERROR,
  2176 without any side effect on output channels.  The Isar toplevel takes
  2177 care of proper display of ERROR exceptions.  ML code may use plain
  2178 handle/can/try; cat_error may be used to concatenate errors like this:
  2179 
  2180   ... handle ERROR msg => cat_error msg "..."
  2181 
  2182 Toplevel ML code (run directly or through the Isar toplevel) may be
  2183 embedded into the Isar toplevel with exception display/debug like
  2184 this:
  2185 
  2186   Isar.toplevel (fn () => ...)
  2187 
  2188 INCOMPATIBILITY, removed special transform_error facilities, removed
  2189 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2190 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2191 -- use plain ERROR instead.
  2192 
  2193 * Isar: theory setup now has type (theory -> theory), instead of a
  2194 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2195 
  2196 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2197 ProofContext.debug/verbose flags.
  2198 
  2199 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2200 theory before entering a proof state.  Transactions now always see a
  2201 quasi-functional intermediate checkpoint, both in interactive and
  2202 batch mode.
  2203 
  2204 * Isar: simplified interfaces for outer syntax.  Renamed
  2205 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2206 OuterSyntax.add_parsers -- this functionality is now included in
  2207 OuterSyntax.command etc.  INCOMPATIBILITY.
  2208 
  2209 * Simplifier: the simpset of a running simplification process now
  2210 contains a proof context (cf. Simplifier.the_context), which is the
  2211 very context that the initial simpset has been retrieved from (by
  2212 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2213 (solver, looper etc.) may depend on arbitrary proof data.
  2214 
  2215 * Simplifier.inherit_context inherits the proof context (plus the
  2216 local bounds) of the current simplification process; any simproc
  2217 etc. that calls the Simplifier recursively should do this!  Removed
  2218 former Simplifier.inherit_bounds, which is already included here --
  2219 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2220 specify an explicit context using Simplifier.context/theory_context.
  2221 
  2222 * Simplifier/Classical Reasoner: more abstract interfaces
  2223 change_simpset/claset for modifying the simpset/claset reference of a
  2224 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2225 INCOMPATIBILITY.
  2226 
  2227 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2228 "Trueprop" etc.
  2229 
  2230 
  2231 *** System ***
  2232 
  2233 * settings: the default heap location within ISABELLE_HOME_USER now
  2234 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2235 Isabelle installations.
  2236 
  2237 * isabelle-process: option -S (secure mode) disables some critical
  2238 operations, notably runtime compilation and evaluation of ML source
  2239 code.
  2240 
  2241 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2242 
  2243 * Support for parallel execution, using native multicore support of
  2244 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2245 independent theories, according to the given theory header
  2246 specifications. The maximum number of worker threads is specified via
  2247 usedir option -M or the "max-threads" setting in Proof General. A
  2248 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2249 to 6 on a 8-core machine.  User-code needs to observe certain
  2250 guidelines for thread-safe programming, see appendix A in the Isar
  2251 Implementation manual.
  2252 
  2253 
  2254 
  2255 New in Isabelle2005 (October 2005)
  2256 ----------------------------------
  2257 
  2258 *** General ***
  2259 
  2260 * Theory headers: the new header syntax for Isar theories is
  2261 
  2262   theory <name>
  2263   imports <theory1> ... <theoryN>
  2264   uses <file1> ... <fileM>
  2265   begin
  2266 
  2267 where the 'uses' part is optional.  The previous syntax
  2268 
  2269   theory <name> = <theory1> + ... + <theoryN>:
  2270 
  2271 will disappear in the next release.  Use isatool fixheaders to convert
  2272 existing theory files.  Note that there is no change in ancient
  2273 non-Isar theories now, but these will disappear soon.
  2274 
  2275 * Theory loader: parent theories can now also be referred to via
  2276 relative and absolute paths.
  2277 
  2278 * Command 'find_theorems' searches for a list of criteria instead of a
  2279 list of constants. Known criteria are: intro, elim, dest, name:string,
  2280 simp:term, and any term. Criteria can be preceded by '-' to select
  2281 theorems that do not match. Intro, elim, dest select theorems that
  2282 match the current goal, name:s selects theorems whose fully qualified
  2283 name contain s, and simp:term selects all simplification rules whose
  2284 lhs match term.  Any other term is interpreted as pattern and selects
  2285 all theorems matching the pattern. Available in ProofGeneral under
  2286 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2287 
  2288   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2289 
  2290 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2291 matching the current goal as introduction rule and not having "HOL."
  2292 in their name (i.e. not being defined in theory HOL).
  2293 
  2294 * Command 'thms_containing' has been discontinued in favour of
  2295 'find_theorems'; INCOMPATIBILITY.
  2296 
  2297 * Communication with Proof General is now 8bit clean, which means that
  2298 Unicode text in UTF-8 encoding may be used within theory texts (both
  2299 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2300 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2301 
  2302   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2303   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2304 
  2305 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2306 Classical Reasoner.  Typical big applications run around 2 times
  2307 faster.
  2308 
  2309 
  2310 *** Document preparation ***
  2311 
  2312 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2313 of raw sources.  Only those symbols that do not require additional
  2314 LaTeX packages (depending on comments in isabellesym.sty) are
  2315 displayed properly, everything else is left verbatim.  isatool display
  2316 and isatool print are used as front ends (these are subject to the
  2317 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2318 
  2319 * Command tags control specific markup of certain regions of text,
  2320 notably folding and hiding.  Predefined tags include "theory" (for
  2321 theory begin and end), "proof" for proof commands, and "ML" for
  2322 commands involving ML code; the additional tags "visible" and
  2323 "invisible" are unused by default.  Users may give explicit tag
  2324 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2325 interpretation of tags is determined by the LaTeX job during document
  2326 preparation: see option -V of isatool usedir, or options -n and -t of
  2327 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2328 \isadroptag.
  2329 
  2330 Several document versions may be produced at the same time via isatool
  2331 usedir (the generated index.html will link all of them).  Typical
  2332 specifications include ''-V document=theory,proof,ML'' to present
  2333 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2334 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2335 these parts without any formal replacement text.  The Isabelle site
  2336 default settings produce ''document'' and ''outline'' versions as
  2337 specified above.
  2338 
  2339 * Several new antiquotations:
  2340 
  2341   @{term_type term} prints a term with its type annotated;
  2342 
  2343   @{typeof term} prints the type of a term;
  2344 
  2345   @{const const} is the same as @{term const}, but checks that the
  2346   argument is a known logical constant;
  2347 
  2348   @{term_style style term} and @{thm_style style thm} print a term or
  2349   theorem applying a "style" to it
  2350 
  2351   @{ML text}
  2352 
  2353 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2354 definitions, equations, inequations etc., 'concl' printing only the
  2355 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2356 to print the specified premise.  TermStyle.add_style provides an ML
  2357 interface for introducing further styles.  See also the "LaTeX Sugar"
  2358 document practical applications.  The ML antiquotation prints
  2359 type-checked ML expressions verbatim.
  2360 
  2361 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2362 and 'text' support optional locale specification '(in loc)', which
  2363 specifies the default context for interpreting antiquotations.  For
  2364 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2365 
  2366 * Option 'locale=NAME' of antiquotations specifies an alternative
  2367 context interpreting the subsequent argument.  For example: @{thm
  2368 [locale=lattice] inf_assoc}.
  2369 
  2370 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2371 a proof context.
  2372 
  2373 * Proper output of antiquotations for theory commands involving a
  2374 proof context (such as 'locale' or 'theorem (in loc) ...').
  2375 
  2376 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2377 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2378 
  2379 * isatool usedir: new option -C (default true) controls whether option
  2380 -D should include a copy of the original document directory; -C false
  2381 prevents unwanted effects such as copying of administrative CVS data.
  2382 
  2383 
  2384 *** Pure ***
  2385 
  2386 * Considerably improved version of 'constdefs' command.  Now performs
  2387 automatic type-inference of declared constants; additional support for
  2388 local structure declarations (cf. locales and HOL records), see also
  2389 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2390 sequential dependencies of definitions within a single 'constdefs'
  2391 section; moreover, the declared name needs to be an identifier.  If
  2392 all fails, consider to fall back on 'consts' and 'defs' separately.
  2393 
  2394 * Improved indexed syntax and implicit structures.  First of all,
  2395 indexed syntax provides a notational device for subscripted
  2396 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2397 expressions.  Secondly, in a local context with structure
  2398 declarations, number indexes \<^sub>n or the empty index (default
  2399 number 1) refer to a certain fixed variable implicitly; option
  2400 show_structs controls printing of implicit structures.  Typical
  2401 applications of these concepts involve record types and locales.
  2402 
  2403 * New command 'no_syntax' removes grammar declarations (and
  2404 translations) resulting from the given syntax specification, which is
  2405 interpreted in the same manner as for the 'syntax' command.
  2406 
  2407 * 'Advanced' translation functions (parse_translation etc.) may depend
  2408 on the signature of the theory context being presently used for
  2409 parsing/printing, see also isar-ref manual.
  2410 
  2411 * Improved 'oracle' command provides a type-safe interface to turn an
  2412 ML expression of type theory -> T -> term into a primitive rule of
  2413 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2414 is already included here); see also FOL/ex/IffExample.thy;
  2415 INCOMPATIBILITY.
  2416 
  2417 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2418 before); "cI" is no longer bound, use "c.intro" instead.
  2419 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2420 axclasses vs. locales.
  2421 
  2422 * Improved internal renaming of symbolic identifiers -- attach primes
  2423 instead of base 26 numbers.
  2424 
  2425 * New flag show_question_marks controls printing of leading question
  2426 marks in schematic variable names.
  2427 
  2428 * In schematic variable names, *any* symbol following \<^isub> or
  2429 \<^isup> is now treated as part of the base name.  For example, the
  2430 following works without printing of awkward ".0" indexes:
  2431 
  2432   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2433     by simp
  2434 
  2435 * Inner syntax includes (*(*nested*) comments*).
  2436 
  2437 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2438 annotations as "(00...)".
  2439 
  2440 * Clear separation of logical types and nonterminals, where the latter
  2441 may only occur in 'syntax' specifications or type abbreviations.
  2442 Before that distinction was only partially implemented via type class
  2443 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2444 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2445 exotic syntax specifications may require further adaption
  2446 (e.g. Cube/Cube.thy).
  2447 
  2448 * Removed obsolete type class "logic", use the top sort {} instead.
  2449 Note that non-logical types should be declared as 'nonterminals'
  2450 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2451 specifications.
  2452 
  2453 * Attributes 'induct' and 'cases': type or set names may now be
  2454 locally fixed variables as well.
  2455 
  2456 * Simplifier: can now control the depth to which conditional rewriting
  2457 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2458 Limit.
  2459 
  2460 * Simplifier: simplification procedures may now take the current
  2461 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2462 interface), which is very useful for calling the Simplifier
  2463 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2464 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2465 low-level mk_simproc no longer applies Logic.varify internally, to
  2466 allow for use in a context of fixed variables.
  2467 
  2468 * thin_tac now works even if the assumption being deleted contains !!
  2469 or ==>.  More generally, erule now works even if the major premise of
  2470 the elimination rule contains !! or ==>.
  2471 
  2472 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2473 
  2474 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2475 from Pure, which contains all common declarations already.  Both
  2476 theories are defined via plain Isabelle/Isar .thy files.
  2477 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2478 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2479 use isatool fixcpure to adapt your theory and ML sources.
  2480 
  2481 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2482 selections of theorems in named facts via index ranges.
  2483 
  2484 * 'print_theorems': in theory mode, really print the difference
  2485 wrt. the last state (works for interactive theory development only),
  2486 in proof mode print all local facts (cf. 'print_facts');
  2487 
  2488 * 'hide': option '(open)' hides only base names.
  2489 
  2490 * More efficient treatment of intermediate checkpoints in interactive
  2491 theory development.
  2492 
  2493 * Code generator is now invoked via code_module (incremental code
  2494 generation) and code_library (modular code generation, ML structures
  2495 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2496 must be quoted when used as identifiers.
  2497 
  2498 * New 'value' command for reading, evaluating and printing terms using
  2499 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2500 quoted when used as identifier.
  2501 
  2502 
  2503 *** Locales ***
  2504 
  2505 * New commands for the interpretation of locale expressions in
  2506 theories (1), locales (2) and proof contexts (3).  These generate
  2507 proof obligations from the expression specification.  After the
  2508 obligations have been discharged, theorems of the expression are added
  2509 to the theory, target locale or proof context.  The synopsis of the
  2510 commands is a follows:
  2511 
  2512   (1) interpretation expr inst
  2513   (2) interpretation target < expr
  2514   (3) interpret expr inst
  2515 
  2516 Interpretation in theories and proof contexts require a parameter
  2517 instantiation of terms from the current context.  This is applied to
  2518 specifications and theorems of the interpreted expression.
  2519 Interpretation in locales only permits parameter renaming through the
  2520 locale expression.  Interpretation is smart in that interpretations
  2521 that are active already do not occur in proof obligations, neither are
  2522 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2523 inspect active interpretations of a particular locale.  For details,
  2524 see the Isar Reference manual.  Examples can be found in
  2525 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2526 
  2527 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2528 'interpret' instead.
  2529 
  2530 * New context element 'constrains' for adding type constraints to
  2531 parameters.
  2532 
  2533 * Context expressions: renaming of parameters with syntax
  2534 redeclaration.
  2535 
  2536 * Locale declaration: 'includes' disallowed.
  2537 
  2538 * Proper static binding of attribute syntax -- i.e. types / terms /
  2539 facts mentioned as arguments are always those of the locale definition
  2540 context, independently of the context of later invocations.  Moreover,
  2541 locale operations (renaming and type / term instantiation) are applied
  2542 to attribute arguments as expected.
  2543 
  2544 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2545 actual attributes; rare situations may require Attrib.attribute to
  2546 embed those attributes into Attrib.src that lack concrete syntax.
  2547 Attribute implementations need to cooperate properly with the static
  2548 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2549 Attrib.XXX_thm etc. already do the right thing without further
  2550 intervention.  Only unusual applications -- such as "where" or "of"
  2551 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2552 on the context and the facts involved -- may have to assign parsed
  2553 values to argument tokens explicitly.
  2554 
  2555 * Changed parameter management in theorem generation for long goal
  2556 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2557 theorem statement in rare situations.
  2558 
  2559 * Locale inspection command 'print_locale' omits notes elements.  Use
  2560 'print_locale!' to have them included in the output.
  2561 
  2562 
  2563 *** Provers ***
  2564 
  2565 * Provers/hypsubst.ML: improved version of the subst method, for
  2566 single-step rewriting: it now works in bound variable contexts. New is
  2567 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2568 rewrite a different subterm than the original subst method, which is
  2569 still available as 'simplesubst'.
  2570 
  2571 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2572 and quasi orders.
  2573 
  2574 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2575 reflexive-transitive closure of relations.
  2576 
  2577 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2578 limit (previously hard-coded with a value of 20) user-definable.
  2579 
  2580 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2581 is peformed already.  Object-logics merely need to finish their
  2582 initial simpset configuration as before.  INCOMPATIBILITY.
  2583 
  2584 
  2585 *** HOL ***
  2586 
  2587 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2588 
  2589   syntax (epsilon)
  2590     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2591 
  2592 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2593 and x-symbol; use option '-m epsilon' to get it actually printed.
  2594 Moreover, the mathematically important symbolic identifier \<epsilon>
  2595 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2596 
  2597 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2598 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2599 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2600 support corresponding Isar calculations.
  2601 
  2602 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2603 instead of ":".
  2604 
  2605 * theory SetInterval: changed the syntax for open intervals:
  2606 
  2607   Old       New
  2608   {..n(}    {..<n}
  2609   {)n..}    {n<..}
  2610   {m..n(}   {m..<n}
  2611   {)m..n}   {m<..n}
  2612   {)m..n(}  {m<..<n}
  2613 
  2614 The old syntax is still supported but will disappear in the next
  2615 release.  For conversion use the following Emacs search and replace
  2616 patterns (these are not perfect but work quite well):
  2617 
  2618   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2619   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2620 
  2621 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2622 equalities in commutative rings; method 'algebra' provides a generic
  2623 interface.
  2624 
  2625 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2626 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2627 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2628 be a tuple pattern.
  2629 
  2630 Some new syntax forms are available:
  2631 
  2632   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2633   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2634   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2635   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2636 
  2637 The latter form "\<Sum>x < k. e" used to be based on a separate
  2638 function "Summation", which has been discontinued.
  2639 
  2640 * theory Finite_Set: in structured induction proofs, the insert case
  2641 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2642 (insert F x)'.
  2643 
  2644 * The 'refute' command has been extended to support a much larger
  2645 fragment of HOL, including axiomatic type classes, constdefs and
  2646 typedefs, inductive datatypes and recursion.
  2647 
  2648 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2649 Requires zChaff with proof generation to be installed.  See
  2650 HOL/ex/SAT_Examples.thy for examples.
  2651 
  2652 * Datatype induction via method 'induct' now preserves the name of the
  2653 induction variable. For example, when proving P(xs::'a list) by
  2654 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2655 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2656 in unstructured proof scripts.
  2657 
  2658 * Reworked implementation of records.  Improved scalability for
  2659 records with many fields, avoiding performance problems for type
  2660 inference. Records are no longer composed of nested field types, but
  2661 of nested extension types. Therefore the record type only grows linear
  2662 in the number of extensions and not in the number of fields.  The
  2663 top-level (users) view on records is preserved.  Potential
  2664 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2665 old record representation. The type generated for a record is called
  2666 <record_name>_ext_type.
  2667 
  2668 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2669 proofs triggered by a record definition or a simproc (if
  2670 quick_and_dirty is enabled).  Definitions of large records can take
  2671 quite long.
  2672 
  2673 New simproc record_upd_simproc for simplification of multiple record
  2674 updates enabled by default.  Moreover, trivial updates are also
  2675 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2676 occasionally, since simplification is more powerful by default.
  2677 
  2678 * typedef: proper support for polymorphic sets, which contain extra
  2679 type-variables in the term.
  2680 
  2681 * Simplifier: automatically reasons about transitivity chains
  2682 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2683 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2684 old proofs break occasionally as simplification may now solve more
  2685 goals than previously.
  2686 
  2687 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2688 present.  Works for all partial orders (class "order"), in particular
  2689 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2690 just like y <= x.
  2691 
  2692 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2693 bound variable or a constant then the let is unfolded.  Otherwise
  2694 first a is simplified to b, and then f b is simplified to g. If
  2695 possible we abstract b from g arriving at "let x = b in h x",
  2696 otherwise we unfold the let and arrive at g.  The simproc can be
  2697 enabled/disabled by the reference use_let_simproc.  Potential
  2698 INCOMPATIBILITY since simplification is more powerful by default.
  2699 
  2700 * Classical reasoning: the meson method now accepts theorems as arguments.
  2701 
  2702 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2703 jobs to provide advice on the provability of subgoals.
  2704 
  2705 * Theory OrderedGroup and Ring_and_Field: various additions and
  2706 improvements to faciliate calculations involving equalities and
  2707 inequalities.
  2708 
  2709 The following theorems have been eliminated or modified
  2710 (INCOMPATIBILITY):
  2711 
  2712   abs_eq             now named abs_of_nonneg
  2713   abs_of_ge_0        now named abs_of_nonneg
  2714   abs_minus_eq       now named abs_of_nonpos
  2715   imp_abs_id         now named abs_of_nonneg
  2716   imp_abs_neg_id     now named abs_of_nonpos
  2717   mult_pos           now named mult_pos_pos
  2718   mult_pos_le        now named mult_nonneg_nonneg
  2719   mult_pos_neg_le    now named mult_nonneg_nonpos
  2720   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2721   mult_neg           now named mult_neg_neg
  2722   mult_neg_le        now named mult_nonpos_nonpos
  2723 
  2724 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2725      
  2726      zero_le_square
  2727      not_square_less_zero 
  2728 
  2729   The following lemmas have been deleted from Real/RealPow:
  2730   
  2731      realpow_zero_zero
  2732      realpow_two
  2733      realpow_less
  2734      zero_le_power
  2735      realpow_two_le
  2736      abs_realpow_two
  2737      realpow_two_abs     
  2738 
  2739 * Theory Parity: added rules for simplifying exponents.
  2740 
  2741 * Theory List:
  2742 
  2743 The following theorems have been eliminated or modified
  2744 (INCOMPATIBILITY):
  2745 
  2746   list_all_Nil       now named list_all.simps(1)
  2747   list_all_Cons      now named list_all.simps(2)
  2748   list_all_conv      now named list_all_iff
  2749   set_mem_eq         now named mem_iff
  2750 
  2751 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  2752 asymptotic "big O" calculations.  See the notes in BigO.thy.
  2753 
  2754 
  2755 *** HOL-Complex ***
  2756 
  2757 * Theory RealDef: better support for embedding natural numbers and
  2758 integers in the reals.
  2759 
  2760 The following theorems have been eliminated or modified
  2761 (INCOMPATIBILITY):
  2762 
  2763   exp_ge_add_one_self  now requires no hypotheses
  2764   real_of_int_add      reversed direction of equality (use [symmetric])
  2765   real_of_int_minus    reversed direction of equality (use [symmetric])
  2766   real_of_int_diff     reversed direction of equality (use [symmetric])
  2767   real_of_int_mult     reversed direction of equality (use [symmetric])
  2768 
  2769 * Theory RComplete: expanded support for floor and ceiling functions.
  2770 
  2771 * Theory Ln is new, with properties of the natural logarithm
  2772 
  2773 * Hyperreal: There is a new type constructor "star" for making
  2774 nonstandard types.  The old type names are now type synonyms:
  2775 
  2776   hypreal = real star
  2777   hypnat = nat star
  2778   hcomplex = complex star
  2779 
  2780 * Hyperreal: Many groups of similarly-defined constants have been
  2781 replaced by polymorphic versions (INCOMPATIBILITY):
  2782 
  2783   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2784 
  2785   starset      <-- starsetNat, starsetC
  2786   *s*          <-- *sNat*, *sc*
  2787   starset_n    <-- starsetNat_n, starsetC_n
  2788   *sn*         <-- *sNatn*, *scn*
  2789   InternalSets <-- InternalNatSets, InternalCSets
  2790 
  2791   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2792   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2793   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2794   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2795   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2796 
  2797 * Hyperreal: Many type-specific theorems have been removed in favor of
  2798 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2799 
  2800   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2801   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2802   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2803   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2804   right_minus <-- hypreal_add_minus
  2805   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2806   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2807   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2808   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2809   mult_1_right <-- hcomplex_mult_one_right
  2810   mult_zero_left <-- hcomplex_mult_zero_left
  2811   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2812   right_distrib <-- hypnat_add_mult_distrib2
  2813   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2814   right_inverse <-- hypreal_mult_inverse
  2815   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2816   order_refl <-- {hypreal,hypnat}_le_refl
  2817   order_trans <-- {hypreal,hypnat}_le_trans
  2818   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2819   order_less_le <-- {hypreal,hypnat}_less_le
  2820   linorder_linear <-- {hypreal,hypnat}_le_linear
  2821   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2822   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2823   add_nonneg_nonneg <-- hypreal_le_add_order
  2824 
  2825 * Hyperreal: Separate theorems having to do with type-specific
  2826 versions of constants have been merged into theorems that apply to the
  2827 new polymorphic constants (INCOMPATIBILITY):
  2828 
  2829   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2830   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2831   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2832   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2833   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2834   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2835   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2836   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2837   STAR_diff <-- {STAR,STARC}_diff
  2838   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2839     STARC_hcomplex_of_complex}_image_subset
  2840   starset_n_Un <-- starset{Nat,C}_n_Un
  2841   starset_n_Int <-- starset{Nat,C}_n_Int
  2842   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2843   starset_n_diff <-- starset{Nat,C}_n_diff
  2844   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2845   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2846   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2847   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2848   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2849   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2850   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2851   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2852   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2853   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2854   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2855   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2856   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2857   starfun_diff <-- starfun{C,RC,CR}_diff
  2858   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2859   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2860   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2861   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2862   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2863   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2864   starfun_Id <-- starfunC_Id
  2865   starfun_approx <-- starfun{Nat,CR}_approx
  2866   starfun_capprox <-- starfun{C,RC}_capprox
  2867   starfun_abs <-- starfunNat_rabs
  2868   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2869   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2870   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2871   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2872   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2873   starfun_add_approx <-- starfunCR_add_approx
  2874   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2875   starfun_divide <-- starfun{C,CR,RC}_divide
  2876   starfun_n <-- starfun{Nat,C}_n
  2877   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2878   starfun_n_add <-- starfun{Nat,C}_n_add
  2879   starfun_n_add_minus <-- starfunNat_n_add_minus
  2880   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2881   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2882   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2883 
  2884   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2885   star_n_minus <-- {hypreal,hcomplex}_minus
  2886   star_n_diff <-- {hypreal,hcomplex}_diff
  2887   star_n_mult <-- {hypreal,hcomplex}_mult
  2888   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2889   star_n_le <-- {hypreal,hypnat}_le
  2890   star_n_less <-- {hypreal,hypnat}_less
  2891   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2892   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2893   star_n_abs <-- hypreal_hrabs
  2894   star_n_divide <-- hcomplex_divide
  2895 
  2896   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2897   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2898   star_of_diff <-- hypreal_of_real_diff
  2899   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2900   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2901   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2902   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2903   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2904   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2905   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2906   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2907   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2908   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2909   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2910   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2911   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2912   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2913   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2914   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2915   star_of_power <-- hypreal_of_real_power
  2916   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2917 
  2918 * Hyperreal: new method "transfer" that implements the transfer
  2919 principle of nonstandard analysis. With a subgoal that mentions
  2920 nonstandard types like "'a star", the command "apply transfer"
  2921 replaces it with an equivalent one that mentions only standard types.
  2922 To be successful, all free variables must have standard types; non-
  2923 standard variables must have explicit universal quantifiers.
  2924 
  2925 * Hyperreal: A theory of Taylor series.
  2926 
  2927 
  2928 *** HOLCF ***
  2929 
  2930 * Discontinued special version of 'constdefs' (which used to support
  2931 continuous functions) in favor of the general Pure one with full
  2932 type-inference.
  2933 
  2934 * New simplification procedure for solving continuity conditions; it
  2935 is much faster on terms with many nested lambda abstractions (cubic
  2936 instead of exponential time).
  2937 
  2938 * New syntax for domain package: selector names are now optional.
  2939 Parentheses should be omitted unless argument is lazy, for example:
  2940 
  2941   domain 'a stream = cons "'a" (lazy "'a stream")
  2942 
  2943 * New command 'fixrec' for defining recursive functions with pattern
  2944 matching; defining multiple functions with mutual recursion is also
  2945 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2946 sinr, or any data constructor defined by the domain package. The given
  2947 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2948 syntax and examples.
  2949 
  2950 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2951 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2952 but the proof obligation additionally includes an admissibility
  2953 requirement. The packages generate instances of class cpo or pcpo,
  2954 with continuity and strictness theorems for Rep and Abs.
  2955 
  2956 * HOLCF: Many theorems have been renamed according to a more standard naming
  2957 scheme (INCOMPATIBILITY):
  2958 
  2959   foo_inject:  "foo$x = foo$y ==> x = y"
  2960   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2961   foo_less:    "(foo$x << foo$y) = (x << y)"
  2962   foo_strict:  "foo$UU = UU"
  2963   foo_defined: "... ==> foo$x ~= UU"
  2964   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2965 
  2966 
  2967 *** ZF ***
  2968 
  2969 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2970 including the First Isomorphism Theorem (on quotienting by the kernel
  2971 of a homomorphism).
  2972 
  2973 * ZF/Simplifier: install second copy of type solver that actually
  2974 makes use of TC rules declared to Isar proof contexts (or locales);
  2975 the old version is still required for ML proof scripts.
  2976 
  2977 
  2978 *** Cube ***
  2979 
  2980 * Converted to Isar theory format; use locales instead of axiomatic
  2981 theories.
  2982 
  2983 
  2984 *** ML ***
  2985 
  2986 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2987 for ||>, ||>>, |>>,
  2988 
  2989 * Pure/library.ML no longer defines its own option datatype, but uses
  2990 that of the SML basis, which has constructors NONE and SOME instead of
  2991 None and Some, as well as exception Option.Option instead of OPTION.
  2992 The functions the, if_none, is_some, is_none have been adapted
  2993 accordingly, while Option.map replaces apsome.
  2994 
  2995 * Pure/library.ML: the exception LIST has been given up in favour of
  2996 the standard exceptions Empty and Subscript, as well as
  2997 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2998 superceded by the standard hd and tl functions etc.
  2999 
  3000 A number of basic list functions are no longer exported to the ML
  3001 toplevel, as they are variants of predefined functions.  The following
  3002 suggests how one can translate existing code:
  3003 
  3004     rev_append xs ys = List.revAppend (xs, ys)
  3005     nth_elem (i, xs) = List.nth (xs, i)
  3006     last_elem xs = List.last xs
  3007     flat xss = List.concat xss
  3008     seq fs = List.app fs
  3009     partition P xs = List.partition P xs
  3010     mapfilter f xs = List.mapPartial f xs
  3011 
  3012 * Pure/library.ML: several combinators for linear functional
  3013 transformations, notably reverse application and composition:
  3014 
  3015   x |> f                f #> g
  3016   (x, y) |-> f          f #-> g
  3017 
  3018 * Pure/library.ML: introduced/changed precedence of infix operators:
  3019 
  3020   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3021   infix 2 ?;
  3022   infix 3 o oo ooo oooo;
  3023   infix 4 ~~ upto downto;
  3024 
  3025 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3026 infix operators.
  3027 
  3028 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3029 fold_map support linear functional transformations and nesting.  For
  3030 example:
  3031 
  3032   fold f [x1, ..., xN] y =
  3033     y |> f x1 |> ... |> f xN
  3034 
  3035   (fold o fold) f [xs1, ..., xsN] y =
  3036     y |> fold f xs1 |> ... |> fold f xsN
  3037 
  3038   fold f [x1, ..., xN] =
  3039     f x1 #> ... #> f xN
  3040 
  3041   (fold o fold) f [xs1, ..., xsN] =
  3042     fold f xs1 #> ... #> fold f xsN
  3043 
  3044 * Pure/library.ML: the following selectors on type 'a option are
  3045 available:
  3046 
  3047   the:               'a option -> 'a  (*partial*)
  3048   these:             'a option -> 'a  where 'a = 'b list
  3049   the_default: 'a -> 'a option -> 'a
  3050   the_list:          'a option -> 'a list
  3051 
  3052 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3053 basic operations for association lists, following natural argument
  3054 order; moreover the explicit equality predicate passed here avoids
  3055 potentially expensive polymorphic runtime equality checks.
  3056 The old functions may be expressed as follows:
  3057 
  3058   assoc = uncurry (AList.lookup (op =))
  3059   assocs = these oo AList.lookup (op =)
  3060   overwrite = uncurry (AList.update (op =)) o swap
  3061 
  3062 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3063 
  3064   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3065   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3066 
  3067 replacing make_keylist and keyfilter (occassionally used)
  3068 Naive rewrites:
  3069 
  3070   make_keylist = AList.make
  3071   keyfilter = AList.find (op =)
  3072 
  3073 * eq_fst and eq_snd now take explicit equality parameter, thus
  3074   avoiding eqtypes. Naive rewrites:
  3075 
  3076     eq_fst = eq_fst (op =)
  3077     eq_snd = eq_snd (op =)
  3078 
  3079 * Removed deprecated apl and apr (rarely used).
  3080   Naive rewrites:
  3081 
  3082     apl (n, op) =>>= curry op n
  3083     apr (op, m) =>>= fn n => op (n, m)
  3084 
  3085 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3086 provides a reasonably efficient light-weight implementation of sets as
  3087 lists.
  3088 
  3089 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3090 few new operations; existing lookup and update are now curried to
  3091 follow natural argument order (for use with fold etc.);
  3092 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3093 
  3094 * Pure/General: output via the Isabelle channels of
  3095 writeln/warning/error etc. is now passed through Output.output, with a
  3096 hook for arbitrary transformations depending on the print_mode
  3097 (cf. Output.add_mode -- the first active mode that provides a output
  3098 function wins).  Already formatted output may be embedded into further
  3099 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3100 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3101 accommodate easy composition of diagnostic messages etc.  Programmers
  3102 rarely need to care about Output.output or Output.raw at all, with
  3103 some notable exceptions: Output.output is required when bypassing the
  3104 standard channels (writeln etc.), or in token translations to produce
  3105 properly formatted results; Output.raw is required when capturing
  3106 already output material that will eventually be presented to the user
  3107 a second time.  For the default print mode, both Output.output and
  3108 Output.raw have no effect.
  3109 
  3110 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3111 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3112 cumulative results are displayed at the end of a batch session.
  3113 
  3114 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3115 replaced by File.platform_path and File.shell_path (with appropriate
  3116 hooks).  This provides a clean interface for unusual systems where the
  3117 internal and external process view of file names are different.
  3118 
  3119 * Pure: more efficient orders for basic syntactic entities: added
  3120 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3121 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3122 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3123 orders now -- potential INCOMPATIBILITY for code that depends on a
  3124 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3125 Library.sort_strings on result).
  3126 
  3127 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3128 fold_types traverse types/terms from left to right, observing natural
  3129 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3130 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3131 
  3132 * Pure: name spaces have been refined, with significant changes of the
  3133 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3134 to extern(_table).  The plain name entry path is superceded by a
  3135 general 'naming' context, which also includes the 'policy' to produce
  3136 a fully qualified name and external accesses of a fully qualified
  3137 name; NameSpace.extend is superceded by context dependent
  3138 Sign.declare_name.  Several theory and proof context operations modify
  3139 the naming context.  Especially note Theory.restore_naming and
  3140 ProofContext.restore_naming to get back to a sane state; note that
  3141 Theory.add_path is no longer sufficient to recover from
  3142 Theory.absolute_path in particular.
  3143 
  3144 * Pure: new flags short_names (default false) and unique_names
  3145 (default true) for controlling output of qualified names.  If
  3146 short_names is set, names are printed unqualified.  If unique_names is
  3147 reset, the name prefix is reduced to the minimum required to achieve
  3148 the original result when interning again, even if there is an overlap
  3149 with earlier declarations.
  3150 
  3151 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3152 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3153 (useful for printing error messages).  INCOMPATIBILITY.
  3154 
  3155 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3156 Theory.theory are now identified, referring to the universal
  3157 Context.theory (see Pure/context.ML).  Actual signature and theory
  3158 content is managed as theory data.  The old code and interfaces were
  3159 spread over many files and structures; the new arrangement introduces
  3160 considerable INCOMPATIBILITY to gain more clarity:
  3161 
  3162   Context -- theory management operations (name, identity, inclusion,
  3163     parents, ancestors, merge, etc.), plus generic theory data;
  3164 
  3165   Sign -- logical signature and syntax operations (declaring consts,
  3166     types, etc.), plus certify/read for common entities;
  3167 
  3168   Theory -- logical theory operations (stating axioms, definitions,
  3169     oracles), plus a copy of logical signature operations (consts,
  3170     types, etc.); also a few basic management operations (Theory.copy,
  3171     Theory.merge, etc.)
  3172 
  3173 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3174 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3175 for convenience -- they merely return the theory.
  3176 
  3177 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3178 
  3179 * Pure: the Isar proof context type is already defined early in Pure
  3180 as Context.proof (note that ProofContext.context and Proof.context are
  3181 aliases, where the latter is the preferred name).  This enables other
  3182 Isabelle components to refer to that type even before Isar is present.
  3183 
  3184 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3185 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3186 any of these kinds.  For example, Sign.intern typeK is now
  3187 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3188 Theory.hide_types.  Also note that former
  3189 Theory.hide_classes/types/consts are now
  3190 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3191 internalize their arguments!  INCOMPATIBILITY.
  3192 
  3193 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3194 datatype thmref (with constructors Name and NameSelection) instead of
  3195 plain string -- INCOMPATIBILITY;
  3196 
  3197 * Pure: cases produced by proof methods specify options, where NONE
  3198 means to remove case bindings -- INCOMPATIBILITY in
  3199 (RAW_)METHOD_CASES.
  3200 
  3201 * Pure: the following operations retrieve axioms or theorems from a
  3202 theory node or theory hierarchy, respectively:
  3203 
  3204   Theory.axioms_of: theory -> (string * term) list
  3205   Theory.all_axioms_of: theory -> (string * term) list
  3206   PureThy.thms_of: theory -> (string * thm) list
  3207   PureThy.all_thms_of: theory -> (string * thm) list
  3208 
  3209 * Pure: print_tac now outputs the goal through the trace channel.
  3210 
  3211 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3212 Reference Toplevel.debug (default false) controls detailed printing
  3213 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3214 controls execution profiling -- set to 1 for time and 2 for space
  3215 (both increase the runtime).
  3216 
  3217 * Isar session: The initial use of ROOT.ML is now always timed,
  3218 i.e. the log will show the actual process times, in contrast to the
  3219 elapsed wall-clock time that the outer shell wrapper produces.
  3220 
  3221 * Simplifier: improved handling of bound variables (nameless
  3222 representation, avoid allocating new strings).  Simprocs that invoke
  3223 the Simplifier recursively should use Simplifier.inherit_bounds to
  3224 avoid local name clashes.  Failure to do so produces warnings
  3225 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3226 for further details.
  3227 
  3228 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3229 bindings for all theorems stored within a given theory; this may help
  3230 in porting non-Isar theories to Isar ones, while keeping ML proof
  3231 scripts for the time being.
  3232 
  3233 * ML operator HTML.with_charset specifies the charset begin used for
  3234 generated HTML files.  For example:
  3235 
  3236   HTML.with_charset "utf-8" use_thy "Hebrew";
  3237   HTML.with_charset "utf-8" use_thy "Chinese";
  3238 
  3239 
  3240 *** System ***
  3241 
  3242 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3243 isabelle, isatool etc.).
  3244 
  3245 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3246 isatool doc, isatool mkdir, display_drafts etc.).
  3247 
  3248 * isatool usedir: option -f allows specification of the ML file to be
  3249 used by Isabelle; default is ROOT.ML.
  3250 
  3251 * New isatool version outputs the version identifier of the Isabelle
  3252 distribution being used.
  3253 
  3254 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3255 (containing Boolean satisfiability problems) into Isabelle/HOL
  3256 theories.
  3257 
  3258 
  3259 
  3260 New in Isabelle2004 (April 2004)
  3261 --------------------------------
  3262 
  3263 *** General ***
  3264 
  3265 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3266   Replaces linorder.ML.
  3267 
  3268 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3269   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3270   (\<a>...\<z>), are now considered normal letters, and can therefore
  3271   be used anywhere where an ASCII letter (a...zA...Z) has until
  3272   now. COMPATIBILITY: This obviously changes the parsing of some
  3273   terms, especially where a symbol has been used as a binder, say
  3274   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3275   as an identifier.  Fix it by inserting a space around former
  3276   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3277   existing theory and ML files.
  3278 
  3279 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3280 
  3281 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3282   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3283   a normal (but invisible) letter. For multiple letter subscripts repeat
  3284   \<^isub> like this: x\<^isub>1\<^isub>2.
  3285 
  3286 * Pure: There are now sub-/superscripts that can span more than one
  3287   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3288   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3289   superscript. The new control characters are not identifier parts.
  3290 
  3291 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3292   content of "..." to the latex file instead of \isacntrl... . The "..."
  3293   may consist of any printable characters excluding the end bracket >.
  3294 
  3295 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3296   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3297   declare constants "final", which prevents their being given a definition
  3298   later.  It is useful for constants whose behaviour is fixed axiomatically
  3299   rather than definitionally, such as the meta-logic connectives.
  3300 
  3301 * Pure: 'instance' now handles general arities with general sorts
  3302   (i.e. intersections of classes),
  3303 
  3304 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3305   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3306   It can be changed to alter the colors/layout of generated pages.
  3307 
  3308 
  3309 *** Isar ***
  3310 
  3311 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3312   cut_tac, subgoal_tac and thin_tac:
  3313   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3314     locales are no longer forced to write Isar proof scripts.
  3315     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3316     emulations.
  3317   - INCOMPATIBILITY: names of variables to be instantiated may no
  3318     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3319     This is consistent with the instantiation attribute "where".
  3320 
  3321 * Attributes "where" and "of":
  3322   - Now take type variables of instantiated theorem into account when reading
  3323     the instantiation string.  This fixes a bug that caused instantiated
  3324     theorems to have too special types in some circumstances.
  3325   - "where" permits explicit instantiations of type variables.
  3326 
  3327 * Calculation commands "moreover" and "also" no longer interfere with
  3328   current facts ("this"), admitting arbitrary combinations with "then"
  3329   and derived forms.
  3330 
  3331 * Locales:
  3332   - Goal statements involving the context element "includes" no longer
  3333     generate theorems with internal delta predicates (those ending on
  3334     "_axioms") in the premise.
  3335     Resolve particular premise with <locale>.intro to obtain old form.
  3336   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3337     specification and "includes" elements in goal statement.
  3338   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3339     [intro?] and [elim?] (respectively) by default.
  3340   - Experimental command for instantiation of locales in proof contexts:
  3341         instantiate <label>[<attrs>]: <loc>
  3342     Instantiates locale <loc> and adds all its theorems to the current context
  3343     taking into account their attributes.  Label and attrs are optional
  3344     modifiers, like in theorem declarations.  If present, names of
  3345     instantiated theorems are qualified with <label>, and the attributes
  3346     <attrs> are applied after any attributes these theorems might have already.
  3347       If the locale has assumptions, a chained fact of the form
  3348     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3349     are derived.  The command does not support old-style locales declared
  3350     with "locale (open)".
  3351       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3352 
  3353 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3354   (Isar) contexts.
  3355 
  3356 
  3357 *** HOL ***
  3358 
  3359 * Proof import: new image HOL4 contains the imported library from
  3360   the HOL4 system with about 2500 theorems. It is imported by
  3361   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3362   can be used like any other Isabelle image.  See
  3363   HOL/Import/HOL/README for more information.
  3364 
  3365 * Simplifier:
  3366   - Much improved handling of linear and partial orders.
  3367     Reasoners for linear and partial orders are set up for type classes
  3368     "linorder" and "order" respectively, and are added to the default simpset
  3369     as solvers.  This means that the simplifier can build transitivity chains
  3370     to solve goals from the assumptions.
  3371   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3372     of blast or auto after simplification become unnecessary because the goal
  3373     is solved by simplification already.
  3374 
  3375 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3376     all proved in axiomatic type classes for semirings, rings and fields.
  3377 
  3378 * Numerics:
  3379   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3380     now formalized using the Ring_and_Field theory mentioned above.
  3381   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3382     than before, because now they are set up once in a generic manner.
  3383   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3384     Look for the general versions in Ring_and_Field (and Power if they concern
  3385     exponentiation).
  3386 
  3387 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3388 
  3389 * Records:
  3390   - Record types are now by default printed with their type abbreviation
  3391     instead of the list of all field types. This can be configured via
  3392     the reference "print_record_type_abbr".
  3393   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3394     (not enabled by default).
  3395   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3396     EX x. x = sel r to True (not enabled by default).
  3397   - Tactic "record_split_simp_tac" to split and simplify records added.
  3398 
  3399 * 'specification' command added, allowing for definition by
  3400   specification.  There is also an 'ax_specification' command that
  3401   introduces the new constants axiomatically.
  3402 
  3403 * arith(_tac) is now able to generate counterexamples for reals as well.
  3404 
  3405 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3406 
  3407 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3408   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3409 
  3410 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3411   matrix theory to linear programming.
  3412 
  3413 * Unions and Intersections:
  3414   The latex output syntax of UN and INT has been changed
  3415   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3416   i.e. the index formulae has become a subscript.
  3417   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3418 
  3419 * Unions and Intersections over Intervals:
  3420   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3421   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3422   like in normal math, and corresponding versions for < and for intersection.
  3423 
  3424 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3425   lexicographic dictonary ordering has been added as "lexord".
  3426 
  3427 * ML: the legacy theory structures Int and List have been removed. They had
  3428   conflicted with ML Basis Library structures having the same names.
  3429 
  3430 * 'refute' command added to search for (finite) countermodels.  Only works
  3431   for a fragment of HOL.  The installation of an external SAT solver is
  3432   highly recommended.  See "HOL/Refute.thy" for details.
  3433 
  3434 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3435   formulae under an assignment of free variables to random values.
  3436   In contrast to 'refute', it can deal with inductive datatypes,
  3437   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3438   for examples.
  3439 
  3440 
  3441 *** HOLCF ***
  3442 
  3443 * Streams now come with concatenation and are part of the HOLCF image
  3444 
  3445 
  3446 
  3447 New in Isabelle2003 (May 2003)
  3448 ------------------------------
  3449 
  3450 *** General ***
  3451 
  3452 * Provers/simplifier:
  3453 
  3454   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3455     Assumptions are now subject to complete mutual simplification,
  3456     not just from left to right. The simplifier now preserves
  3457     the order of assumptions.
  3458 
  3459     Potential INCOMPATIBILITY:
  3460 
  3461     -- simp sometimes diverges where the old version did
  3462        not, e.g. invoking simp on the goal
  3463 
  3464         [| P (f x); y = x; f x = f y |] ==> Q
  3465 
  3466        now gives rise to the infinite reduction sequence
  3467 
  3468         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3469 
  3470        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3471        kind of problem.
  3472 
  3473     -- Tactics combining classical reasoner and simplification (such as auto)
  3474        are also affected by this change, because many of them rely on
  3475        simp. They may sometimes diverge as well or yield a different numbers
  3476        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3477        in case of problems. Sometimes subsequent calls to the classical
  3478        reasoner will fail because a preceeding call to the simplifier too
  3479        eagerly simplified the goal, e.g. deleted redundant premises.
  3480 
  3481   - The simplifier trace now shows the names of the applied rewrite rules
  3482 
  3483   - You can limit the number of recursive invocations of the simplifier
  3484     during conditional rewriting (where the simplifie tries to solve the
  3485     conditions before applying the rewrite rule):
  3486     ML "simp_depth_limit := n"
  3487     where n is an integer. Thus you can force termination where previously
  3488     the simplifier would diverge.
  3489 
  3490   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3491 
  3492   - No longer aborts on failed congruence proof.  Instead, the
  3493     congruence is ignored.
  3494 
  3495 * Pure: New generic framework for extracting programs from constructive
  3496   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3497   as HOL/Extraction for some case studies.
  3498 
  3499 * Pure: The main goal of the proof state is no longer shown by default, only
  3500 the subgoals. This behaviour is controlled by a new flag.
  3501    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3502 (ML: Proof.show_main_goal).
  3503 
  3504 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3505 rules whose conclusion matches subgoal 1:
  3506       PG menu: Isabelle/Isar -> Show me -> matching rules
  3507 The rules are ordered by how closely they match the subgoal.
  3508 In particular, rules that solve a subgoal outright are displayed first
  3509 (or rather last, the way they are printed).
  3510 (ML: ProofGeneral.print_intros())
  3511 
  3512 * Pure: New flag trace_unify_fail causes unification to print
  3513 diagnostic information (PG: in trace buffer) when it fails. This is
  3514 useful for figuring out why single step proofs like rule, erule or
  3515 assumption failed.
  3516 
  3517 * Pure: Locale specifications now produce predicate definitions
  3518 according to the body of text (covering assumptions modulo local
  3519 definitions); predicate "loc_axioms" covers newly introduced text,
  3520 while "loc" is cumulative wrt. all included locale expressions; the
  3521 latter view is presented only on export into the global theory
  3522 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3523 on the old view without predicates;
  3524 
  3525 * Pure: predefined locales "var" and "struct" are useful for sharing
  3526 parameters (as in CASL, for example); just specify something like
  3527 ``var x + var y + struct M'' as import;
  3528 
  3529 * Pure: improved thms_containing: proper indexing of facts instead of
  3530 raw theorems; check validity of results wrt. current name space;
  3531 include local facts of proof configuration (also covers active
  3532 locales), cover fixed variables in index; may use "_" in term
  3533 specification; an optional limit for the number of printed facts may
  3534 be given (the default is 40);
  3535 
  3536 * Pure: disallow duplicate fact bindings within new-style theory files
  3537 (batch-mode only);
  3538 
  3539 * Provers: improved induct method: assumptions introduced by case
  3540 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3541 the goal statement); "foo" still refers to all facts collectively;
  3542 
  3543 * Provers: the function blast.overloaded has been removed: all constants
  3544 are regarded as potentially overloaded, which improves robustness in exchange
  3545 for slight decrease in efficiency;
  3546 
  3547 * Provers/linorder: New generic prover for transitivity reasoning over
  3548 linear orders.  Note: this prover is not efficient!
  3549 
  3550 * Isar: preview of problems to finish 'show' now produce an error
  3551 rather than just a warning (in interactive mode);
  3552 
  3553 
  3554 *** HOL ***
  3555 
  3556 * arith(_tac)
  3557 
  3558  - Produces a counter example if it cannot prove a goal.
  3559    Note that the counter example may be spurious if the goal is not a formula
  3560    of quantifier-free linear arithmetic.
  3561    In ProofGeneral the counter example appears in the trace buffer.
  3562 
  3563  - Knows about div k and mod k where k is a numeral of type nat or int.
  3564 
  3565  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3566    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3567    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3568 
  3569 * simp's arithmetic capabilities have been enhanced a bit: it now
  3570 takes ~= in premises into account (by performing a case split);
  3571 
  3572 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3573 are distributed over a sum of terms;
  3574 
  3575 * New tactic "trans_tac" and method "trans" instantiate
  3576 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3577 "<=", "<" and "=").
  3578 
  3579 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3580 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3581 
  3582 * 'typedef' command has new option "open" to suppress the set
  3583 definition;
  3584 
  3585 * functions Min and Max on finite sets have been introduced (theory
  3586 Finite_Set);
  3587 
  3588 * attribute [symmetric] now works for relations as well; it turns
  3589 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3590 
  3591 * induct over a !!-quantified statement (say !!x1..xn):
  3592   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3593 
  3594 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3595 %x. None. Warning: empty_def now refers to the previously hidden definition
  3596 of the empty set.
  3597 
  3598 * Algebra: formalization of classical algebra.  Intended as base for
  3599 any algebraic development in Isabelle.  Currently covers group theory
  3600 (up to Sylow's theorem) and ring theory (Universal Property of
  3601 Univariate Polynomials).  Contributions welcome;
  3602 
  3603 * GroupTheory: deleted, since its material has been moved to Algebra;
  3604 
  3605 * Complex: new directory of the complex numbers with numeric constants,
  3606 nonstandard complex numbers, and some complex analysis, standard and
  3607 nonstandard (Jacques Fleuriot);
  3608 
  3609 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3610 
  3611 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3612 Fleuriot);
  3613 
  3614 * Real/HahnBanach: updated and adapted to locales;
  3615 
  3616 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3617 Gray and Kramer);
  3618 
  3619 * UNITY: added the Meier-Sanders theory of progress sets;
  3620 
  3621 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3622 as abstract algorithms, instantiated to the JVM;
  3623 
  3624 * Bali: Java source language formalization. Type system, operational
  3625 semantics, axiomatic semantics. Supported language features:
  3626 classes, interfaces, objects,virtual methods, static methods,
  3627 static/instance fields, arrays, access modifiers, definite
  3628 assignment, exceptions.
  3629 
  3630 
  3631 *** ZF ***
  3632 
  3633 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3634 universe, etc.);
  3635 
  3636 * Main ZF: virtually all theories converted to new-style format;
  3637 
  3638 
  3639 *** ML ***
  3640 
  3641 * Pure: Tactic.prove provides sane interface for internal proofs;
  3642 omits the infamous "standard" operation, so this is more appropriate
  3643 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3644 
  3645 * Pure: improved error reporting of simprocs;
  3646 
  3647 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3648 up simprocs;
  3649 
  3650 
  3651 *** Document preparation ***
  3652 
  3653 * uses \par instead of \\ for line breaks in theory text. This may
  3654 shift some page breaks in large documents. To get the old behaviour
  3655 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3656 
  3657 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3658 other packages
  3659 
  3660 * \<euro> now needs package babel/greek instead of marvosym (which
  3661 broke \Rightarrow)
  3662 
  3663 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3664 textcomp package)
  3665 
  3666 
  3667 
  3668 New in Isabelle2002 (March 2002)
  3669 --------------------------------
  3670 
  3671 *** Document preparation ***
  3672 
  3673 * greatly simplified document preparation setup, including more
  3674 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3675 instructive isatool mkdir; users should basically be able to get
  3676 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3677 users may run a separate document processing stage manually like this:
  3678 "isatool usedir -D output HOL Test && isatool document Test/output";
  3679 
  3680 * theory dependency graph may now be incorporated into documents;
  3681 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3682 with \includegraphics of LaTeX;
  3683 
  3684 * proper spacing of consecutive markup elements, especially text
  3685 blocks after section headings;
  3686 
  3687 * support bold style (for single symbols only), input syntax is like
  3688 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3689 
  3690 * \<bullet> is now output as bold \cdot by default, which looks much
  3691 better in printed text;
  3692 
  3693 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3694 note that these symbols are currently unavailable in Proof General /
  3695 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3696 
  3697 * isatool latex no longer depends on changed TEXINPUTS, instead
  3698 isatool document copies the Isabelle style files to the target
  3699 location;
  3700 
  3701 
  3702 *** Isar ***
  3703 
  3704 * Pure/Provers: improved proof by cases and induction;
  3705   - 'case' command admits impromptu naming of parameters (such as
  3706     "case (Suc n)");
  3707   - 'induct' method divinates rule instantiation from the inductive
  3708     claim; no longer requires excessive ?P bindings for proper
  3709     instantiation of cases;
  3710   - 'induct' method properly enumerates all possibilities of set/type
  3711     rules; as a consequence facts may be also passed through *type*
  3712     rules without further ado;
  3713   - 'induct' method now derives symbolic cases from the *rulified*
  3714     rule (before it used to rulify cases stemming from the internal
  3715     atomized version); this means that the context of a non-atomic
  3716     statement becomes is included in the hypothesis, avoiding the
  3717     slightly cumbersome show "PROP ?case" form;
  3718   - 'induct' may now use elim-style induction rules without chaining
  3719     facts, using ``missing'' premises from the goal state; this allows
  3720     rules stemming from inductive sets to be applied in unstructured
  3721     scripts, while still benefitting from proper handling of non-atomic
  3722     statements; NB: major inductive premises need to be put first, all
  3723     the rest of the goal is passed through the induction;
  3724   - 'induct' proper support for mutual induction involving non-atomic
  3725     rule statements (uses the new concept of simultaneous goals, see
  3726     below);
  3727   - append all possible rule selections, but only use the first
  3728     success (no backtracking);
  3729   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3730   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3731   - added 'print_induct_rules' (covered by help item in recent Proof
  3732     General versions);
  3733   - moved induct/cases attributes to Pure, methods to Provers;
  3734   - generic method setup instantiated for FOL and HOL;
  3735 
  3736 * Pure: support multiple simultaneous goal statements, for example
  3737 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3738 meta-level mechanism, this acts as if several individual goals had
  3739 been stated separately; in particular common proof methods need to be
  3740 repeated in order to cover all claims; note that a single elimination
  3741 step is *not* sufficient to establish the two conjunctions, so this
  3742 fails:
  3743 
  3744   assume "A & B" then have A and B ..   (*".." fails*)
  3745 
  3746 better use "obtain" in situations as above; alternative refer to
  3747 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  3748 
  3749 * Pure: proper integration with ``locales''; unlike the original
  3750 version by Florian Kammller, Isar locales package high-level proof
  3751 contexts rather than raw logical ones (e.g. we admit to include
  3752 attributes everywhere); operations on locales include merge and
  3753 rename; support for implicit arguments (``structures''); simultaneous
  3754 type-inference over imports and text; see also HOL/ex/Locales.thy for
  3755 some examples;
  3756 
  3757 * Pure: the following commands have been ``localized'', supporting a
  3758 target locale specification "(in name)": 'lemma', 'theorem',
  3759 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  3760 stored both within the locale and at the theory level (exported and
  3761 qualified by the locale name);
  3762 
  3763 * Pure: theory goals may now be specified in ``long'' form, with
  3764 ad-hoc contexts consisting of arbitrary locale elements. for example
  3765 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  3766 definitions may be given, too); the result is a meta-level rule with
  3767 the context elements being discharged in the obvious way;
  3768 
  3769 * Pure: new proof command 'using' allows to augment currently used
  3770 facts after a goal statement ('using' is syntactically analogous to
  3771 'apply', but acts on the goal's facts only); this allows chained facts
  3772 to be separated into parts given before and after a claim, as in
  3773 ``from a and b have C using d and e <proof>'';
  3774 
  3775 * Pure: renamed "antecedent" case to "rule_context";
  3776 
  3777 * Pure: new 'judgment' command records explicit information about the
  3778 object-logic embedding (used by several tools internally); no longer
  3779 use hard-wired "Trueprop";
  3780 
  3781 * Pure: added 'corollary' command;
  3782 
  3783 * Pure: fixed 'token_translation' command;
  3784 
  3785 * Pure: removed obsolete 'exported' attribute;
  3786 
  3787 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3788 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3789 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3790 
  3791 * Pure: method 'atomize' presents local goal premises as object-level
  3792 statements (atomic meta-level propositions); setup controlled via
  3793 rewrite rules declarations of 'atomize' attribute; example
  3794 application: 'induct' method with proper rule statements in improper
  3795 proof *scripts*;
  3796 
  3797 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3798 now consider the syntactic context of assumptions, giving a better
  3799 chance to get type-inference of the arguments right (this is
  3800 especially important for locales);
  3801 
  3802 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3803 mode;
  3804 
  3805 * Pure/obtain: the formal conclusion "thesis", being marked as
  3806 ``internal'', may no longer be reference directly in the text;
  3807 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3808 situations;
  3809 
  3810 * Pure: generic 'sym' attribute which declares a rule both as pure
  3811 'elim?' and for the 'symmetric' operation;
  3812 
  3813 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3814 text; the fixed correlation with particular command syntax has been
  3815 discontinued;
  3816 
  3817 * Pure: new method 'rules' is particularly well-suited for proof
  3818 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3819 but often produces more compact proof terms with less detours;
  3820 
  3821 * Pure/Provers/classical: simplified integration with pure rule
  3822 attributes and methods; the classical "intro?/elim?/dest?"
  3823 declarations coincide with the pure ones; the "rule" method no longer
  3824 includes classically swapped intros; "intro" and "elim" methods no
  3825 longer pick rules from the context; also got rid of ML declarations
  3826 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3827 INCOMPATIBILITY;
  3828 
  3829 * Provers/classical: attribute 'swapped' produces classical inversions
  3830 of introduction rules;
  3831 
  3832 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3833 rules instead of full simplifier context; 'iff' attribute handles
  3834 conditional rules;
  3835 
  3836 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3837 
  3838 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3839 "(permissive)" option to recover old behavior;
  3840 
  3841 * HOL: 'inductive' no longer features separate (collective) attributes
  3842 for 'intros' (was found too confusing);
  3843 
  3844 * HOL: properly declared induction rules less_induct and
  3845 wf_induct_rule;
  3846 
  3847 
  3848 *** HOL ***
  3849 
  3850 * HOL: moved over to sane numeral syntax; the new policy is as
  3851 follows:
  3852 
  3853   - 0 and 1 are polymorphic constants, which are defined on any
  3854   numeric type (nat, int, real etc.);
  3855 
  3856   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3857   binary representation internally;
  3858 
  3859   - type nat has special constructor Suc, and generally prefers Suc 0
  3860   over 1::nat and Suc (Suc 0) over 2::nat;
  3861 
  3862 This change may cause significant problems of INCOMPATIBILITY; here
  3863 are some hints on converting existing sources:
  3864 
  3865   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3866   entities, so expressions involving "-" (unary or binary minus) need
  3867   to be spaced properly;
  3868 
  3869   - existing occurrences of "1" may need to be constraint "1::nat" or
  3870   even replaced by Suc 0; similar for old "2";
  3871 
  3872   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3873 
  3874   - remove all special provisions on numerals in proofs;
  3875 
  3876 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3877 representation (depends on bin_arith_simps in the default context);
  3878 
  3879 * HOL: symbolic syntax for x^2 (numeral 2);
  3880 
  3881 * HOL: the class of all HOL types is now called "type" rather than
  3882 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3883 in axclass/classes, instance/arities, and (usually rare) occurrences
  3884 in typings (of consts etc.); internally the class is called
  3885 "HOL.type", ML programs should refer to HOLogic.typeS;
  3886 
  3887 * HOL/record package improvements:
  3888   - new derived operations "fields" to build a partial record section,
  3889     "extend" to promote a fixed record to a record scheme, and
  3890     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3891     declared as simp by default;
  3892   - shared operations ("more", "fields", etc.) now need to be always
  3893     qualified) --- potential INCOMPATIBILITY;
  3894   - removed "make_scheme" operations (use "make" with "extend") --
  3895     INCOMPATIBILITY;
  3896   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3897   - provides cases/induct rules for use with corresponding Isar
  3898     methods (for concrete records, record schemes, concrete more
  3899     parts, and schematic more parts -- in that order);
  3900   - internal definitions directly based on a light-weight abstract
  3901     theory of product types over typedef rather than datatype;
  3902 
  3903 * HOL: generic code generator for generating executable ML code from
  3904 specifications; specific support for HOL constructs such as inductive
  3905 datatypes and sets, as well as recursive functions; can be invoked
  3906 via 'generate_code' theory section;
  3907 
  3908 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3909 
  3910 * HOL: consolidated and renamed several theories.  In particular:
  3911         Ord.thy has been absorbed into HOL.thy
  3912         String.thy has been absorbed into List.thy
  3913 
  3914 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3915 (beware of argument permutation!);
  3916 
  3917 * HOL: linorder_less_split superseded by linorder_cases;
  3918 
  3919 * HOL/List: "nodups" renamed to "distinct";
  3920 
  3921 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3922 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3923   - Ex_def has changed, now need to use some_eq_ex
  3924 
  3925 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3926 in this (rare) case use:
  3927 
  3928   delSWrapper "split_all_tac"
  3929   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3930 
  3931 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3932 MAY FAIL;
  3933 
  3934 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3935 Isabelle's type classes, ^ on functions and relations has too general
  3936 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3937 necessary to attach explicit type constraints;
  3938 
  3939 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3940 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3941 renamed accordingly (eg "compI" -> "rel_compI").
  3942 
  3943 * HOL: syntax translations now work properly with numerals and records
  3944 expressions;
  3945 
  3946 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3947 of "lam" -- INCOMPATIBILITY;
  3948 
  3949 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3950 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3951 renamed "Product_Type.unit";
  3952 
  3953 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3954 
  3955 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3956 the "cases" method);
  3957 
  3958 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3959 Florian Kammller);
  3960 
  3961 * HOL/IMP: updated and converted to new-style theory format; several
  3962 parts turned into readable document, with proper Isar proof texts and
  3963 some explanations (by Gerwin Klein);
  3964 
  3965 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3966 
  3967 * HOL-Hyperreal is now a logic image;
  3968 
  3969 
  3970 *** HOLCF ***
  3971 
  3972 * Isar: consts/constdefs supports mixfix syntax for continuous
  3973 operations;
  3974 
  3975 * Isar: domain package adapted to new-style theory format, e.g. see
  3976 HOLCF/ex/Dnat.thy;
  3977 
  3978 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3979 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3980 lift.induct_tac, always use UU instead of Undef;
  3981 
  3982 * HOLCF/IMP: updated and converted to new-style theory;
  3983 
  3984 
  3985 *** ZF ***
  3986 
  3987 * Isar: proper integration of logic-specific tools and packages,
  3988 including theory commands '(co)inductive', '(co)datatype',
  3989 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3990 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3991 
  3992 * theory Main no longer includes AC; for the Axiom of Choice, base
  3993 your theory on Main_ZFC;
  3994 
  3995 * the integer library now covers quotients and remainders, with many
  3996 laws relating division to addition, multiplication, etc.;
  3997 
  3998 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3999 typeless version of the formalism;
  4000 
  4001 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4002 format;
  4003 
  4004 * ZF/Induct: new directory for examples of inductive definitions,
  4005 including theory Multiset for multiset orderings; converted to
  4006 new-style theory format;
  4007 
  4008 * ZF: many new theorems about lists, ordinals, etc.;
  4009 
  4010 
  4011 *** General ***
  4012 
  4013 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4014 variable proof controls level of detail: 0 = no proofs (only oracle
  4015 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4016 also ref manual for further ML interfaces;
  4017 
  4018 * Pure/axclass: removed obsolete ML interface
  4019 goal_subclass/goal_arity;
  4020 
  4021 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4022 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4023 separate tokens, so expressions involving minus need to be spaced
  4024 properly;
  4025 
  4026 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4027 rather than "infixl" or "infixr";
  4028 
  4029 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4030 sort constraint specifications in type inference; e.g. "x::_::foo"
  4031 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4032 type variable);
  4033 
  4034 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4035 control output of nested => (types); the default behavior is
  4036 "type_brackets";
  4037 
  4038 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4039 tokens into AST constants;
  4040 
  4041 * Pure/syntax: prefer later declarations of translations and print
  4042 translation functions; potential INCOMPATIBILITY: need to reverse
  4043 multiple declarations for same syntax element constant;
  4044 
  4045 * Pure/show_hyps reset by default (in accordance to existing Isar
  4046 practice);
  4047 
  4048 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4049 addSafter;
  4050 
  4051 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4052 as well;
  4053 
  4054 * system: tested support for MacOS X; should be able to get Isabelle +
  4055 Proof General to work in a plain Terminal after installing Poly/ML
  4056 (e.g. from the Isabelle distribution area) and GNU bash alone
  4057 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4058 support requires further installations, e.g. from
  4059 http://fink.sourceforge.net/);
  4060 
  4061 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4062 
  4063 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4064 of 40 MB), cf. ML_OPTIONS;
  4065 
  4066 * system: Proof General keywords specification is now part of the
  4067 Isabelle distribution (see etc/isar-keywords.el);
  4068 
  4069 * system: support for persistent Proof General sessions (refrain from
  4070 outdating all loaded theories on startup); user may create writable
  4071 logic images like this: ``isabelle -q HOL Test'';
  4072 
  4073 * system: smart selection of Isabelle process versus Isabelle
  4074 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4075 run both "isabelle" and "Isabelle" even if file names are badly
  4076 damaged (executable inspects the case of the first letter of its own
  4077 name); added separate "isabelle-process" and "isabelle-interface";
  4078 
  4079 * system: refrain from any attempt at filtering input streams; no
  4080 longer support ``8bit'' encoding of old isabelle font, instead proper
  4081 iso-latin characters may now be used; the related isatools
  4082 "symbolinput" and "nonascii" have disappeared as well;
  4083 
  4084 * system: removed old "xterm" interface (the print modes "xterm" and
  4085 "xterm_color" are still available for direct use in a suitable
  4086 terminal);
  4087 
  4088 
  4089 
  4090 New in Isabelle99-2 (February 2001)
  4091 -----------------------------------
  4092 
  4093 *** Overview of INCOMPATIBILITIES ***
  4094 
  4095 * HOL: please note that theories in the Library and elsewhere often use the
  4096 new-style (Isar) format; to refer to their theorems in an ML script you must
  4097 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4098 
  4099 * HOL: inductive package no longer splits induction rule aggressively,
  4100 but only as far as specified by the introductions given; the old
  4101 format may be recovered via ML function complete_split_rule or attribute
  4102 'split_rule (complete)';
  4103 
  4104 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4105 gfp_Tarski to gfp_unfold;
  4106 
  4107 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4108 
  4109 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4110 relation); infix "^^" has been renamed "``"; infix "``" has been
  4111 renamed "`"; "univalent" has been renamed "single_valued";
  4112 
  4113 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4114 operation;
  4115 
  4116 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4117 
  4118 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4119 
  4120 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4121 consequence, it is no longer monotonic wrt. the local goal context
  4122 (which is now passed through the inductive cases);
  4123 
  4124 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4125 \<gg> to \<ggreater>;
  4126 
  4127 
  4128 *** Document preparation ***
  4129 
  4130 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4131 available: are "it" for near math-mode best-style output, "sl" for
  4132 slanted text style, and "tt" for plain type-writer; if no
  4133 \isabellestyle command is given, output is according to slanted
  4134 type-writer);
  4135 
  4136 * support sub/super scripts (for single symbols only), input syntax is
  4137 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4138 
  4139 * some more standard symbols; see Appendix A of the system manual for
  4140 the complete list of symbols defined in isabellesym.sty;
  4141 
  4142 * improved isabelle style files; more abstract symbol implementation
  4143 (should now use \isamath{...} and \isatext{...} in custom symbol
  4144 definitions);
  4145 
  4146 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4147 state; Note that presentation of goal states does not conform to
  4148 actual human-readable proof documents.  Please do not include goal
  4149 states into document output unless you really know what you are doing!
  4150 
  4151 * proper indentation of antiquoted output with proportional LaTeX
  4152 fonts;
  4153 
  4154 * no_document ML operator temporarily disables LaTeX document
  4155 generation;
  4156 
  4157 * isatool unsymbolize tunes sources for plain ASCII communication;
  4158 
  4159 
  4160 *** Isar ***
  4161 
  4162 * Pure: Isar now suffers initial goal statements to contain unbound
  4163 schematic variables (this does not conform to actual readable proof
  4164 documents, due to unpredictable outcome and non-compositional proof
  4165 checking); users who know what they are doing may use schematic goals
  4166 for Prolog-style synthesis of proven results;
  4167 
  4168 * Pure: assumption method (an implicit finishing) now handles actual
  4169 rules as well;
  4170 
  4171 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4172 initial goal, declare "that" only as Pure intro (only for single
  4173 steps); the "that" rule assumption may now be involved in implicit
  4174 finishing, thus ".." becomes a feasible for trivial obtains;
  4175 
  4176 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4177 instance proofs may be performed by "..";
  4178 
  4179 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4180 statements as well;
  4181 
  4182 * Pure: more robust selection of calculational rules;
  4183 
  4184 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4185 rule (as well as the assumption rule);
  4186 
  4187 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4188 lemmas, using the graph browser tool;
  4189 
  4190 * Pure: predict failure of "show" in interactive mode;
  4191 
  4192 * Pure: 'thms_containing' now takes actual terms as arguments;
  4193 
  4194 * HOL: improved method 'induct' --- now handles non-atomic goals
  4195 (potential INCOMPATIBILITY); tuned error handling;
  4196 
  4197 * HOL: cases and induct rules now provide explicit hints about the
  4198 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4199 any remaining facts are inserted into the goal verbatim;
  4200 
  4201 * HOL: local contexts (aka cases) may now contain term bindings as
  4202 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4203 the result to be shown in each case;
  4204 
  4205 * HOL: added 'recdef_tc' command;
  4206 
  4207 * isatool convert assists in eliminating legacy ML scripts;
  4208 
  4209 
  4210 *** HOL ***
  4211 
  4212 * HOL/Library: a collection of generic theories to be used together
  4213 with main HOL; the theory loader path already includes this directory
  4214 by default; the following existing theories have been moved here:
  4215 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4216 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4217 
  4218 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4219 modelling and verification task performed in Isabelle/HOL +
  4220 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4221 
  4222 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4223 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4224 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4225 'domain', this makes the theory consistent with mathematical
  4226 literature;
  4227 
  4228 * HOL basics: added overloaded operations "inverse" and "divide"
  4229 (infix "/"), syntax for generic "abs" operation, generic summation
  4230 operator \<Sum>;
  4231 
  4232 * HOL/typedef: simplified package, provide more useful rules (see also
  4233 HOL/subset.thy);
  4234 
  4235 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4236 now expressed as a proper nested rule (old-style tactic scripts may
  4237 require atomize_strip_tac to cope with non-atomic premises);
  4238 
  4239 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4240 to "split_conv" (old name still available for compatibility);
  4241 
  4242 * HOL: improved concrete syntax for strings (e.g. allows translation
  4243 rules with string literals);
  4244 
  4245 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4246  and Fleuriot's mechanization of analysis, including the transcendental
  4247  functions for the reals;
  4248 
  4249 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4250 
  4251 
  4252 *** CTT ***
  4253 
  4254 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4255 "lam" is displayed as TWO lambda-symbols
  4256 
  4257 * CTT: theory Main now available, containing everything (that is, Bool
  4258 and Arith);
  4259 
  4260 
  4261 *** General ***
  4262 
  4263 * Pure: the Simplifier has been implemented properly as a derived rule
  4264 outside of the actual kernel (at last!); the overall performance
  4265 penalty in practical applications is about 50%, while reliability of
  4266 the Isabelle inference kernel has been greatly improved;
  4267 
  4268 * print modes "brackets" and "no_brackets" control output of nested =>
  4269 (types) and ==> (props); the default behaviour is "brackets";
  4270 
  4271 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4272 as assumptions as well;
  4273 
  4274 * system: support Poly/ML 4.0;
  4275 
  4276 * system: isatool install handles KDE version 1 or 2;
  4277 
  4278 
  4279 
  4280 New in Isabelle99-1 (October 2000)
  4281 ----------------------------------
  4282 
  4283 *** Overview of INCOMPATIBILITIES ***
  4284 
  4285 * HOL: simplification of natural numbers is much changed; to partly
  4286 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4287 issue the following ML commands:
  4288 
  4289   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4290   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4291 
  4292 * HOL: simplification no longer dives into case-expressions; this is
  4293 controlled by "t.weak_case_cong" for each datatype t;
  4294 
  4295 * HOL: nat_less_induct renamed to less_induct;
  4296 
  4297 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4298 fixsome to patch .thy and .ML sources automatically;
  4299 
  4300   select_equality  -> some_equality
  4301   select_eq_Ex     -> some_eq_ex
  4302   selectI2EX       -> someI2_ex
  4303   selectI2         -> someI2
  4304   selectI          -> someI
  4305   select1_equality -> some1_equality
  4306   Eps_sym_eq       -> some_sym_eq_trivial
  4307   Eps_eq           -> some_eq_trivial
  4308 
  4309 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4310 
  4311 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4312 instead);
  4313 
  4314 * HOL: the recursion equations generated by 'recdef' are now called
  4315 f.simps instead of f.rules;
  4316 
  4317 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4318 
  4319 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4320 sometimes be needed;
  4321 
  4322 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4323 
  4324 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4325 
  4326 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4327 product is now "<*>" instead of "Times"; the lexicographic product is
  4328 now "<*lex*>" instead of "**";
  4329 
  4330 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4331 of main HOL, but was unused); better use HOL's datatype package;
  4332 
  4333 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4334 the old syntax may be recovered as follows:
  4335 
  4336   syntax (symbols)
  4337     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4338       (infixl "\\<oplus>" 100)
  4339 
  4340 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4341 
  4342 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4343 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4344 internally;
  4345 
  4346 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4347 changed from A/r to A//r;
  4348 
  4349 * ZF: new treatment of arithmetic (nat & int) may break some old
  4350 proofs;
  4351 
  4352 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4353 rulify -> rule_format, elimify -> elim_format, ...);
  4354 
  4355 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4356 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4357 should have to change intro!! to intro? only); replaced "delrule" by
  4358 "rule del";
  4359 
  4360 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4361 
  4362 * Provers: strengthened force_tac by using new first_best_tac;
  4363 
  4364 * LaTeX document preparation: several changes of isabelle.sty (see
  4365 lib/texinputs);
  4366 
  4367 
  4368 *** Document preparation ***
  4369 
  4370 * formal comments (text blocks etc.) in new-style theories may now
  4371 contain antiquotations of thm/prop/term/typ/text to be presented
  4372 according to latex print mode; concrete syntax is like this:
  4373 @{term[show_types] "f(x) = a + x"};
  4374 
  4375 * isatool mkdir provides easy setup of Isabelle session directories,
  4376 including proper document sources;
  4377 
  4378 * generated LaTeX sources are now deleted after successful run
  4379 (isatool document -c); may retain a copy somewhere else via -D option
  4380 of isatool usedir;
  4381 
  4382 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4383 style files, achieving self-contained LaTeX sources and simplifying
  4384 LaTeX debugging;
  4385 
  4386 * old-style theories now produce (crude) LaTeX output as well;
  4387 
  4388 * browser info session directories are now self-contained (may be put
  4389 on WWW server seperately); improved graphs of nested sessions; removed
  4390 graph for 'all sessions';
  4391 
  4392 * several improvements in isabelle style files; \isabellestyle{it}
  4393 produces fake math mode output; \isamarkupheader is now \section by
  4394 default; see lib/texinputs/isabelle.sty etc.;
  4395 
  4396 
  4397 *** Isar ***
  4398 
  4399 * Isar/Pure: local results and corresponding term bindings are now
  4400 subject to Hindley-Milner polymorphism (similar to ML); this
  4401 accommodates incremental type-inference very nicely;
  4402 
  4403 * Isar/Pure: new derived language element 'obtain' supports
  4404 generalized existence reasoning;
  4405 
  4406 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4407 support accumulation of results, without applying any rules yet;
  4408 useful to collect intermediate results without explicit name
  4409 references, and for use with transitivity rules with more than 2
  4410 premises;
  4411 
  4412 * Isar/Pure: scalable support for case-analysis type proofs: new
  4413 'case' language element refers to local contexts symbolically, as
  4414 produced by certain proof methods; internally, case names are attached
  4415 to theorems as "tags";
  4416 
  4417 * Isar/Pure: theory command 'hide' removes declarations from
  4418 class/type/const name spaces;
  4419 
  4420 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4421 indicate potential overloading;
  4422 
  4423 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4424 
  4425 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4426 "{a,b,c}" instead of {a,b,c};
  4427 
  4428 * Isar/Pure now provides its own version of intro/elim/dest
  4429 attributes; useful for building new logics, but beware of confusion
  4430 with the version in Provers/classical;
  4431 
  4432 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4433 case name 'antecedent';
  4434 
  4435 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4436 to the current context is now done automatically);
  4437 
  4438 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4439 for definining proof methods in ML;
  4440 
  4441 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4442 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4443 most cases, one should have to change intro!! to intro? only);
  4444 replaced "delrule" by "rule del";
  4445 
  4446 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4447 'symmetric' attribute (the latter supercedes [RS sym]);
  4448 
  4449 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4450 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4451 well (including splits);
  4452 
  4453 * Isar/Provers: Simplifier and Classical methods now support all kind
  4454 of modifiers used in the past, including 'cong', 'iff', etc.
  4455 
  4456 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4457 of Simplifier and Classical reasoner);
  4458 
  4459 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4460 now support named cases; major packages (inductive, datatype, primrec,
  4461 recdef) support case names and properly name parameters;
  4462 
  4463 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4464 monotonicity conditions are extracted to be proven at end of
  4465 calculations;
  4466 
  4467 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4468 method anyway;
  4469 
  4470 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4471 split_if split_if_asm; datatype package provides theorems foo.splits =
  4472 foo.split foo.split_asm for each datatype;
  4473 
  4474 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4475 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4476 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4477 use "(cases (simplified))" method in proper proof texts);
  4478 
  4479 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4480 
  4481 * Isar: names of theorems etc. may be natural numbers as well;
  4482 
  4483 * Isar: 'pr' command: optional arguments for goals_limit and
  4484 ProofContext.prems_limit; no longer prints theory contexts, but only
  4485 proof states;
  4486 
  4487 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4488 additional print modes to be specified; e.g. "pr(latex)" will print
  4489 proof state according to the Isabelle LaTeX style;
  4490 
  4491 * Isar: improved support for emulating tactic scripts, including proof
  4492 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4493 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4494 (for HOL datatypes);
  4495 
  4496 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4497 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4498 'proof method scripts' have to be in depth-first order;
  4499 
  4500 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4501 
  4502 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4503 should instead use individual commands for printing items
  4504 (print_commands, print_methods etc.);
  4505 
  4506 * Isar: added 'nothing' --- the empty list of theorems;
  4507 
  4508 
  4509 *** HOL ***
  4510 
  4511 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4512 corresponding virtual machine and a specification of its bytecode
  4513 verifier and a lightweight bytecode verifier, including proofs of
  4514 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4515 Cornelia Pusch (see also the homepage of project Bali at
  4516 http://isabelle.in.tum.de/Bali/);
  4517 
  4518 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4519 Clemens Ballarin;
  4520 
  4521 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4522 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4523 Rasmussen;
  4524 
  4525 * HOL/Lattice: fundamental concepts of lattice theory and order
  4526 structures, including duals, properties of bounds versus algebraic
  4527 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4528 Theorem for complete lattices etc.; may also serve as a demonstration
  4529 for abstract algebraic reasoning using axiomatic type classes, and
  4530 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4531 
  4532 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4533 von Oheimb;
  4534 
  4535 * HOL/IMPP: extension of IMP with local variables and mutually
  4536 recursive procedures, by David von Oheimb;
  4537 
  4538 * HOL/Lambda: converted into new-style theory and document;
  4539 
  4540 * HOL/ex/Multiquote: example of multiple nested quotations and
  4541 anti-quotations -- basically a generalized version of de-Bruijn
  4542 representation; very useful in avoiding lifting of operations;
  4543 
  4544 * HOL/record: added general record equality rule to simpset; fixed
  4545 select-update simplification procedure to handle extended records as
  4546 well; admit "r" as field name;
  4547 
  4548 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4549 other numeric types and also as the identity of groups, rings, etc.;
  4550 
  4551 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4552 Types nat and int belong to this axclass;
  4553 
  4554 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4555    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4556    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4557   two terms #m*u and #n*u are replaced by #(m+n)*u
  4558     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4559   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4560     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4561 
  4562 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4563 powerful prover for predicate logic but knows nothing of clasets; see
  4564 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4565 
  4566 * HOL: new version of "case_tac" subsumes both boolean case split and
  4567 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4568 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4569 
  4570 * HOL: simplification no longer dives into case-expressions: only the
  4571 selector expression is simplified, but not the remaining arms; to
  4572 enable full simplification of case-expressions for datatype t, you may
  4573 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4574 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4575 
  4576 * HOL/recdef: the recursion equations generated by 'recdef' for
  4577 function 'f' are now called f.simps instead of f.rules; if all
  4578 termination conditions are proved automatically, these simplification
  4579 rules are added to the simpset, as in primrec; rules may be named
  4580 individually as well, resulting in a separate list of theorems for
  4581 each equation;
  4582 
  4583 * HOL/While is a new theory that provides a while-combinator. It
  4584 permits the definition of tail-recursive functions without the
  4585 provision of a termination measure. The latter is necessary once the
  4586 invariant proof rule for while is applied.
  4587 
  4588 * HOL: new (overloaded) notation for the set of elements below/above
  4589 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4590 
  4591 * HOL: theorems impI, allI, ballI bound as "strip";
  4592 
  4593 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4594 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4595 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4596 
  4597 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4598 
  4599 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4600 main HOL, but was unused);
  4601 
  4602 * HOL: fewer consts declared as global (e.g. have to refer to
  4603 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4604 
  4605 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4606 in case of overlap with user translations (e.g. judgements over
  4607 tuples); (note that the underlying logical represenation is still
  4608 bogus);
  4609 
  4610 
  4611 *** ZF ***
  4612 
  4613 * ZF: simplification automatically cancels common terms in arithmetic
  4614 expressions over nat and int;
  4615 
  4616 * ZF: new treatment of nat to minimize type-checking: all operators
  4617 coerce their operands to a natural number using the function natify,
  4618 making the algebraic laws unconditional;
  4619 
  4620 * ZF: as above, for int: operators coerce their operands to an integer
  4621 using the function intify;
  4622 
  4623 * ZF: the integer library now contains many of the usual laws for the
  4624 orderings, including $<=, and monotonicity laws for $+ and $*;
  4625 
  4626 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4627 simplification;
  4628 
  4629 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4630 to the simplifier and classical reasoner simultaneously;
  4631 
  4632 
  4633 *** General ***
  4634 
  4635 * Provers: blast_tac now handles actual object-logic rules as
  4636 assumptions; note that auto_tac uses blast_tac internally as well;
  4637 
  4638 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4639 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4640 
  4641 * Provers: delrules now handles destruct rules as well (no longer need
  4642 explicit make_elim);
  4643 
  4644 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4645   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4646 use instead the strong form,
  4647   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4648 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4649 from destruct-rules;
  4650 
  4651 * Provers: Simplifier.easy_setup provides a fast path to basic
  4652 Simplifier setup for new object-logics;
  4653 
  4654 * Pure: AST translation rules no longer require constant head on LHS;
  4655 
  4656 * Pure: improved name spaces: ambiguous output is qualified; support
  4657 for hiding of names;
  4658 
  4659 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4660 XSYMBOL_HOME; no longer need to do manual configuration in most
  4661 situations;
  4662 
  4663 * system: compression of ML heaps images may now be controlled via -c
  4664 option of isabelle and isatool usedir (currently only observed by
  4665 Poly/ML);
  4666 
  4667 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4668 useful for remote X11);
  4669 
  4670 * system: provide TAGS file for Isabelle sources;
  4671 
  4672 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4673 order;
  4674 
  4675 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4676 timing flag supersedes proof_timing and Toplevel.trace;
  4677 
  4678 * ML: new combinators |>> and |>>> for incremental transformations
  4679 with secondary results (e.g. certain theory extensions):
  4680 
  4681 * ML: PureThy.add_defs gets additional argument to indicate potential
  4682 overloading (usually false);
  4683 
  4684 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4685 results;
  4686 
  4687 
  4688 
  4689 New in Isabelle99 (October 1999)
  4690 --------------------------------
  4691 
  4692 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4693 
  4694 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4695 are no longer simplified.  (This allows the simplifier to unfold recursive
  4696 functional programs.)  To restore the old behaviour, declare
  4697 
  4698     Delcongs [if_weak_cong];
  4699 
  4700 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4701 complement;
  4702 
  4703 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4704 
  4705 * HOL/datatype: mutual_induct_tac no longer exists --
  4706   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  4707 
  4708 * HOL/typedef: fixed type inference for representing set; type
  4709 arguments now have to occur explicitly on the rhs as type constraints;
  4710 
  4711 * ZF: The con_defs part of an inductive definition may no longer refer
  4712 to constants declared in the same theory;
  4713 
  4714 * HOL, ZF: the function mk_cases, generated by the inductive
  4715 definition package, has lost an argument.  To simplify its result, it
  4716 uses the default simpset instead of a supplied list of theorems.
  4717 
  4718 * HOL/List: the constructors of type list are now Nil and Cons;
  4719 
  4720 * Simplifier: the type of the infix ML functions
  4721         setSSolver addSSolver setSolver addSolver
  4722 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4723 for packaging solvers. A solver is created via
  4724         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4725 where the string argument is only a comment.
  4726 
  4727 
  4728 *** Proof tools ***
  4729 
  4730 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4731 decision procedure for linear arithmetic. Currently it is used for
  4732 types `nat', `int', and `real' in HOL (see below); it can, should and
  4733 will be instantiated for other types and logics as well.
  4734 
  4735 * The simplifier now accepts rewrite rules with flexible heads, eg
  4736      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4737   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4738   matching.
  4739 
  4740 
  4741 *** General ***
  4742 
  4743 * New Isabelle/Isar subsystem provides an alternative to traditional
  4744 tactical theorem proving; together with the ProofGeneral/isar user
  4745 interface it offers an interactive environment for developing human
  4746 readable proof documents (Isar == Intelligible semi-automated
  4747 reasoning); for further information see isatool doc isar-ref,
  4748 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  4749 
  4750 * improved and simplified presentation of theories: better HTML markup
  4751 (including colors), graph views in several sizes; isatool usedir now
  4752 provides a proper interface for user theories (via -P option); actual
  4753 document preparation based on (PDF)LaTeX is available as well (for
  4754 new-style theories only); see isatool doc system for more information;
  4755 
  4756 * native support for Proof General, both for classic Isabelle and
  4757 Isabelle/Isar;
  4758 
  4759 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  4760 using the graph browser tool;
  4761 
  4762 * Isabelle manuals now also available as PDF;
  4763 
  4764 * theory loader rewritten from scratch (may not be fully
  4765 bug-compatible); old loadpath variable has been replaced by show_path,
  4766 add_path, del_path, reset_path functions; new operations such as
  4767 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  4768 isatool doc ref);
  4769 
  4770 * improved isatool install: option -k creates KDE application icon,
  4771 option -p DIR installs standalone binaries;
  4772 
  4773 * added ML_PLATFORM setting (useful for cross-platform installations);
  4774 more robust handling of platform specific ML images for SML/NJ;
  4775 
  4776 * the settings environment is now statically scoped, i.e. it is never
  4777 created again in sub-processes invoked from isabelle, isatool, or
  4778 Isabelle;
  4779 
  4780 * path element specification '~~' refers to '$ISABELLE_HOME';
  4781 
  4782 * in locales, the "assumes" and "defines" parts may be omitted if
  4783 empty;
  4784 
  4785 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4786 long arrows);
  4787 
  4788 * new print_mode "HTML";
  4789 
  4790 * new flag show_tags controls display of tags of theorems (which are
  4791 basically just comments that may be attached by some tools);
  4792 
  4793 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4794 mode and goal output format:
  4795 
  4796 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4797 244c244
  4798 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4799 ---
  4800 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4801 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4802 181c181
  4803 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4804 ---
  4805 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4806 
  4807 * function bind_thms stores lists of theorems (cf. bind_thm);
  4808 
  4809 * new shorthand tactics ftac, eatac, datac, fatac;
  4810 
  4811 * qed (and friends) now accept "" as result name; in that case the
  4812 theorem is not stored, but proper checks and presentation of the
  4813 result still apply;
  4814 
  4815 * theorem database now also indexes constants "Trueprop", "all",
  4816 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4817 
  4818 
  4819 *** HOL ***
  4820 
  4821 ** HOL arithmetic **
  4822 
  4823 * There are now decision procedures for linear arithmetic over nat and
  4824 int:
  4825 
  4826 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4827 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4828 are treated as atomic; subformulae not involving type `nat' or `int'
  4829 are ignored; quantified subformulae are ignored unless they are
  4830 positive universal or negative existential. The tactic has to be
  4831 invoked by hand and can be a little bit slow. In particular, the
  4832 running time is exponential in the number of occurrences of `min' and
  4833 `max', and `-' on `nat'.
  4834 
  4835 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4836 (negated) (in)equalities among the premises and the conclusion into
  4837 account (i.e. no compound formulae) and does not know about `min' and
  4838 `max', and `-' on `nat'. It is fast and is used automatically by the
  4839 simplifier.
  4840 
  4841 NB: At the moment, these decision procedures do not cope with mixed
  4842 nat/int formulae where the two parts interact, such as `m < n ==>
  4843 int(m) < int(n)'.
  4844 
  4845 * HOL/Numeral provides a generic theory of numerals (encoded
  4846 efficiently as bit strings); setup for types nat/int/real is in place;
  4847 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4848 int, existing theories and proof scripts may require a few additional
  4849 type constraints;
  4850 
  4851 * integer division and remainder can now be performed on constant
  4852 arguments;
  4853 
  4854 * many properties of integer multiplication, division and remainder
  4855 are now available;
  4856 
  4857 * An interface to the Stanford Validity Checker (SVC) is available through the
  4858 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4859 are proved automatically.  SVC must be installed separately, and its results
  4860 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4861 invocation of the underlying oracle).  For SVC see
  4862   http://verify.stanford.edu/SVC
  4863 
  4864 * IsaMakefile: the HOL-Real target now builds an actual image;
  4865 
  4866 
  4867 ** HOL misc **
  4868 
  4869 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4870 (in Isabelle/Isar) -- by Gertrud Bauer;
  4871 
  4872 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4873 analysis for assembly languages with subtypes;
  4874 
  4875 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4876 -- avoids syntactic ambiguities and treats state, transition, and
  4877 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4878 changed syntax and (many) tactics;
  4879 
  4880 * HOL/inductive: Now also handles more general introduction rules such
  4881   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4882   theorems are now maintained within the theory (maintained via the
  4883   "mono" attribute);
  4884 
  4885 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4886   (using function types) such as
  4887 
  4888   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4889 
  4890 * HOL/record: record_simproc (part of the default simpset) takes care
  4891 of selectors applied to updated records; record_split_tac is no longer
  4892 part of the default claset; update_defs may now be removed from the
  4893 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4894 
  4895   claset_ref () := claset() addSWrapper record_split_wrapper;
  4896   Delsimprocs [record_simproc]
  4897 
  4898 * HOL/typedef: fixed type inference for representing set; type
  4899 arguments now have to occur explicitly on the rhs as type constraints;
  4900 
  4901 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4902 names rather than an ML expression;
  4903 
  4904 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4905 supplied later.  Program schemes can be defined, such as
  4906     "While B C s = (if B s then While B C (C s) else s)"
  4907 where the well-founded relation can be chosen after B and C have been given.
  4908 
  4909 * HOL/List: the constructors of type list are now Nil and Cons;
  4910 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4911 course, ML tools referring to List.list.op # etc. have to be adapted;
  4912 
  4913 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4914 disabled by default; run isabelle with option -m HOL to get back to
  4915 the original Gordon/HOL-style output;
  4916 
  4917 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4918 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4919 
  4920 * HOL basic syntax simplified (more orthogonal): all variants of
  4921 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4922 Eps operator is provided as well: "SOME x. P[x]";
  4923 
  4924 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4925 
  4926 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4927 thus available for user theories;
  4928 
  4929 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4930 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4931 time;
  4932 
  4933 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4934 several times and then mp;
  4935 
  4936 
  4937 *** LK ***
  4938 
  4939 * the notation <<...>> is now available as a notation for sequences of
  4940 formulas;
  4941 
  4942 * the simplifier is now installed
  4943 
  4944 * the axiom system has been generalized (thanks to Soren Heilmann)
  4945 
  4946 * the classical reasoner now has a default rule database
  4947 
  4948 
  4949 *** ZF ***
  4950 
  4951 * new primrec section allows primitive recursive functions to be given
  4952 directly (as in HOL) over datatypes and the natural numbers;
  4953 
  4954 * new tactics induct_tac and exhaust_tac for induction (or case
  4955 analysis) over datatypes and the natural numbers;
  4956 
  4957 * the datatype declaration of type T now defines the recursor T_rec;
  4958 
  4959 * simplification automatically does freeness reasoning for datatype
  4960 constructors;
  4961 
  4962 * automatic type-inference, with AddTCs command to insert new
  4963 type-checking rules;
  4964 
  4965 * datatype introduction rules are now added as Safe Introduction rules
  4966 to the claset;
  4967 
  4968 * the syntax "if P then x else y" is now available in addition to
  4969 if(P,x,y);
  4970 
  4971 
  4972 *** Internal programming interfaces ***
  4973 
  4974 * tuned simplifier trace output; new flag debug_simp;
  4975 
  4976 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4977 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4978 
  4979 * AxClass.axclass_tac lost the theory argument;
  4980 
  4981 * tuned current_goals_markers semantics: begin / end goal avoids
  4982 printing empty lines;
  4983 
  4984 * removed prs and prs_fn hook, which was broken because it did not
  4985 include \n in its semantics, forcing writeln to add one
  4986 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4987 string -> unit if you really want to output text without newline;
  4988 
  4989 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4990 plain output, interface builders may have to enable 'isabelle_font'
  4991 mode to get Isabelle font glyphs as before;
  4992 
  4993 * refined token_translation interface; INCOMPATIBILITY: output length
  4994 now of type real instead of int;
  4995 
  4996 * theory loader actions may be traced via new ThyInfo.add_hook
  4997 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4998 your own database of information attached to *whole* theories -- as
  4999 opposed to intra-theory data slots offered via TheoryDataFun;
  5000 
  5001 * proper handling of dangling sort hypotheses (at last!);
  5002 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5003 extra sort hypotheses that can be witnessed from the type signature;
  5004 the force_strip_shyps flag is gone, any remaining shyps are simply
  5005 left in the theorem (with a warning issued by strip_shyps_warning);
  5006 
  5007 
  5008 
  5009 New in Isabelle98-1 (October 1998)
  5010 ----------------------------------
  5011 
  5012 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5013 
  5014 * several changes of automated proof tools;
  5015 
  5016 * HOL: major changes to the inductive and datatype packages, including
  5017 some minor incompatibilities of theory syntax;
  5018 
  5019 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5020 called `inj_on';
  5021 
  5022 * HOL: removed duplicate thms in Arith:
  5023   less_imp_add_less  should be replaced by  trans_less_add1
  5024   le_imp_add_le      should be replaced by  trans_le_add1
  5025 
  5026 * HOL: unary minus is now overloaded (new type constraints may be
  5027 required);
  5028 
  5029 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5030 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5031 now taken as an integer constant.
  5032 
  5033 * Pure: ML function 'theory_of' renamed to 'theory';
  5034 
  5035 
  5036 *** Proof tools ***
  5037 
  5038 * Simplifier:
  5039   1. Asm_full_simp_tac is now more aggressive.
  5040      1. It will sometimes reorient premises if that increases their power to
  5041         simplify.
  5042      2. It does no longer proceed strictly from left to right but may also
  5043         rotate premises to achieve further simplification.
  5044      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5045      old Asm_full_simp_tac in that it does not rotate premises.
  5046   2. The simplifier now knows a little bit about nat-arithmetic.
  5047 
  5048 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5049 allows for selected deletion of wrappers, by introduction of names for
  5050 wrapper functionals.  This implies that addbefore, addSbefore,
  5051 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5052 and that adding two tactics with the same name overwrites the first
  5053 one (emitting a warning).
  5054   type wrapper = (int -> tactic) -> (int -> tactic)
  5055   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5056   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5057   delWrapper, delSWrapper: claset *  string            -> claset
  5058   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5059 
  5060 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5061 semantics; addbefore now affects only the unsafe part of step_tac
  5062 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5063 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5064 by Force_tac;
  5065 
  5066 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5067 compWrapper; added safe wrapper (and access functions for it);
  5068 
  5069 * HOL/split_all_tac is now much faster and fails if there is nothing
  5070 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5071 and the names of the automatically generated variables have changed.
  5072 split_all_tac has moved within claset() from unsafe wrappers to safe
  5073 wrappers, which means that !!-bound variables are split much more
  5074 aggressively, and safe_tac and clarify_tac now split such variables.
  5075 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5076 Note: the same holds for record_split_tac, which does the job of
  5077 split_all_tac for record fields.
  5078 
  5079 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5080 permanently to the default simpset using Addsplits just like
  5081 Addsimps. They can be removed via Delsplits just like
  5082 Delsimps. Lower-case versions are also available.
  5083 
  5084 * HOL/Simplifier: The rule split_if is now part of the default
  5085 simpset. This means that the simplifier will eliminate all occurrences
  5086 of if-then-else in the conclusion of a goal. To prevent this, you can
  5087 either remove split_if completely from the default simpset by
  5088 `Delsplits [split_if]' or remove it in a specific call of the
  5089 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5090 other case splitting rules to/from the default simpset: every datatype
  5091 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5092 t is the name of the datatype).
  5093 
  5094 * Classical reasoner / Simplifier combination: new force_tac (and
  5095 derivatives Force_tac, force) combines rewriting and classical
  5096 reasoning (and whatever other tools) similarly to auto_tac, but is
  5097 aimed to solve the given subgoal completely.
  5098 
  5099 
  5100 *** General ***
  5101 
  5102 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5103 and `goalw': the theory is no longer needed as an explicit argument -
  5104 the current theory context is used; assumptions are no longer returned
  5105 at the ML-level unless one of them starts with ==> or !!; it is
  5106 recommended to convert to these new commands using isatool fixgoal
  5107 (backup your sources first!);
  5108 
  5109 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5110 the current theory context, and 'theory' to lookup stored theories;
  5111 
  5112 * new theory section 'locale' for declaring constants, assumptions and
  5113 definitions that have local scope;
  5114 
  5115 * new theory section 'nonterminals' for purely syntactic types;
  5116 
  5117 * new theory section 'setup' for generic ML setup functions
  5118 (e.g. package initialization);
  5119 
  5120 * the distribution now includes Isabelle icons: see
  5121 lib/logo/isabelle-{small,tiny}.xpm;
  5122 
  5123 * isatool install - install binaries with absolute references to
  5124 ISABELLE_HOME/bin;
  5125 
  5126 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5127 
  5128 * print mode 'emacs' reserved for Isamode;
  5129 
  5130 * support multiple print (ast) translations per constant name;
  5131 
  5132 * theorems involving oracles are now printed with a suffixed [!];
  5133 
  5134 
  5135 *** HOL ***
  5136 
  5137 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5138 
  5139 * HOL/inductive package reorganized and improved: now supports mutual
  5140 definitions such as
  5141 
  5142   inductive EVEN ODD
  5143     intrs
  5144       null "0 : EVEN"
  5145       oddI "n : EVEN ==> Suc n : ODD"
  5146       evenI "n : ODD ==> Suc n : EVEN"
  5147 
  5148 new theorem list "elims" contains an elimination rule for each of the
  5149 recursive sets; inductive definitions now handle disjunctive premises
  5150 correctly (also ZF);
  5151 
  5152 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5153 "mutual_induct" no longer exists - the induction rule is always
  5154 contained in "induct";
  5155 
  5156 
  5157 * HOL/datatype package re-implemented and greatly improved: now
  5158 supports mutually recursive datatypes such as
  5159 
  5160   datatype
  5161     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5162             | SUM ('a aexp) ('a aexp)
  5163             | DIFF ('a aexp) ('a aexp)
  5164             | NUM 'a
  5165   and
  5166     'a bexp = LESS ('a aexp) ('a aexp)
  5167             | AND ('a bexp) ('a bexp)
  5168             | OR ('a bexp) ('a bexp)
  5169 
  5170 as well as indirectly recursive datatypes such as
  5171 
  5172   datatype
  5173     ('a, 'b) term = Var 'a
  5174                   | App 'b ((('a, 'b) term) list)
  5175 
  5176 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5177 induction on mutually / indirectly recursive datatypes.
  5178 
  5179 Primrec equations are now stored in theory and can be accessed via
  5180 <function_name>.simps.
  5181 
  5182 INCOMPATIBILITIES:
  5183 
  5184   - Theories using datatypes must now have theory Datatype as an
  5185     ancestor.
  5186   - The specific <typename>.induct_tac no longer exists - use the
  5187     generic induct_tac instead.
  5188   - natE has been renamed to nat.exhaust - use exhaust_tac
  5189     instead of res_inst_tac ... natE. Note that the variable
  5190     names in nat.exhaust differ from the names in natE, this
  5191     may cause some "fragile" proofs to fail.
  5192   - The theorems split_<typename>_case and split_<typename>_case_asm
  5193     have been renamed to <typename>.split and <typename>.split_asm.
  5194   - Since default sorts of type variables are now handled correctly,
  5195     some datatype definitions may have to be annotated with explicit
  5196     sort constraints.
  5197   - Primrec definitions no longer require function name and type
  5198     of recursive argument.
  5199 
  5200 Consider using isatool fixdatatype to adapt your theories and proof
  5201 scripts to the new package (backup your sources first!).
  5202 
  5203 
  5204 * HOL/record package: considerably improved implementation; now
  5205 includes concrete syntax for record types, terms, updates; theorems
  5206 for surjective pairing and splitting !!-bound record variables; proof
  5207 support is as follows:
  5208 
  5209   1) standard conversions (selectors or updates applied to record
  5210 constructor terms) are part of the standard simpset;
  5211 
  5212   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5213 made part of standard simpset and claset via addIffs;
  5214 
  5215   3) a tactic for record field splitting (record_split_tac) is part of
  5216 the standard claset (addSWrapper);
  5217 
  5218 To get a better idea about these rules you may retrieve them via
  5219 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5220 the name of your record type.
  5221 
  5222 The split tactic 3) conceptually simplifies by the following rule:
  5223 
  5224   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5225 
  5226 Thus any record variable that is bound by meta-all will automatically
  5227 blow up into some record constructor term, consequently the
  5228 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5229 solve record problems automatically.
  5230 
  5231 
  5232 * reorganized the main HOL image: HOL/Integ and String loaded by
  5233 default; theory Main includes everything;
  5234 
  5235 * automatic simplification of integer sums and comparisons, using cancellation;
  5236 
  5237 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5238 
  5239 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5240 
  5241 * many new identities for unions, intersections, set difference, etc.;
  5242 
  5243 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5244 called split_if, split_split, split_sum_case and split_nat_case (to go
  5245 with add/delsplits);
  5246 
  5247 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5248 (?x::unit) = (); this is made part of the default simpset, which COULD
  5249 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5250 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5251 unit_abs_eta_conv is added in order to counter the effect of
  5252 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5253 %u.f();
  5254 
  5255 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5256 makes more sense);
  5257 
  5258 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5259   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5260   disjointness reasoning but breaking a few old proofs.
  5261 
  5262 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5263 to 'converse' from 'inverse' (for compatibility with ZF and some
  5264 literature);
  5265 
  5266 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5267 the well-founded relation;
  5268 
  5269 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5270     Compl A.  The "Compl" syntax remains available as input syntax for this
  5271     release ONLY.
  5272 
  5273 * HOL/Update: new theory of function updates:
  5274     f(a:=b) == %x. if x=a then b else f x
  5275 may also be iterated as in f(a:=b,c:=d,...);
  5276 
  5277 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5278 
  5279 * HOL/List:
  5280   - new function list_update written xs[i:=v] that updates the i-th
  5281     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5282   - new function `upt' written [i..j(] which generates the list
  5283     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5284     bound write [i..j], which is a shorthand for [i..j+1(].
  5285   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5286 
  5287 * HOL/Arith:
  5288   - removed 'pred' (predecessor) function;
  5289   - generalized some theorems about n-1;
  5290   - many new laws about "div" and "mod";
  5291   - new laws about greatest common divisors (see theory ex/Primes);
  5292 
  5293 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5294 instead of "inverse";
  5295 
  5296 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5297   of the multiset ordering;
  5298 
  5299 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5300   (not included by default);
  5301 
  5302 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5303 
  5304 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5305   programs, i.e. different program variables may have different types.
  5306 
  5307 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5308   [previously, this check worked only if the rewrite rule was unconditional]
  5309   Now rew can involve either definitions or equalities (either == or =).
  5310 
  5311 
  5312 *** ZF ***
  5313 
  5314 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5315   only the theorems proved on ZF.ML;
  5316 
  5317 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5318   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5319   disjointness reasoning but breaking a few old proofs.
  5320 
  5321 * ZF/Update: new theory of function updates
  5322     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5323   may also be iterated as in f(a:=b,c:=d,...);
  5324 
  5325 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5326 
  5327 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5328   [previously, this check worked only if the rewrite rule was unconditional]
  5329   Now rew can involve either definitions or equalities (either == or =).
  5330 
  5331 * case_tac provided for compatibility with HOL
  5332     (like the old excluded_middle_tac, but with subgoals swapped)
  5333 
  5334 
  5335 *** Internal programming interfaces ***
  5336 
  5337 * Pure: several new basic modules made available for general use, see
  5338 also src/Pure/README;
  5339 
  5340 * improved the theory data mechanism to support encapsulation (data
  5341 kind name replaced by private Object.kind, acting as authorization
  5342 key); new type-safe user interface via functor TheoryDataFun; generic
  5343 print_data function becomes basically useless;
  5344 
  5345 * removed global_names compatibility flag -- all theory declarations
  5346 are qualified by default;
  5347 
  5348 * module Pure/Syntax now offers quote / antiquote translation
  5349 functions (useful for Hoare logic etc. with implicit dependencies);
  5350 see HOL/ex/Antiquote for an example use;
  5351 
  5352 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5353 cterm -> thm;
  5354 
  5355 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5356 subgoal;
  5357 
  5358 * Display.print_goals function moved to Locale.print_goals;
  5359 
  5360 * standard print function for goals supports current_goals_markers
  5361 variable for marking begin of proof, end of proof, start of goal; the
  5362 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5363 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5364 for example;
  5365 
  5366 
  5367 
  5368 New in Isabelle98 (January 1998)
  5369 --------------------------------
  5370 
  5371 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5372 
  5373 * changed lexical syntax of terms / types: dots made part of long
  5374 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5375 
  5376 * simpset (and claset) reference variable replaced by functions
  5377 simpset / simpset_ref;
  5378 
  5379 * no longer supports theory aliases (via merge) and non-trivial
  5380 implicit merge of thms' signatures;
  5381 
  5382 * most internal names of constants changed due to qualified names;
  5383 
  5384 * changed Pure/Sequence interface (see Pure/seq.ML);
  5385 
  5386 
  5387 *** General Changes ***
  5388 
  5389 * hierachically structured name spaces (for consts, types, axms, thms
  5390 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5391 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5392 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5393 long_names for fully qualified output names; NOTE: ML programs
  5394 (special tactics, packages etc.) referring to internal names may have
  5395 to be adapted to cope with fully qualified names; in case of severe
  5396 backward campatibility problems try setting 'global_names' at compile
  5397 time to have enrything declared within a flat name space; one may also
  5398 fine tune name declarations in theories via the 'global' and 'local'
  5399 section;
  5400 
  5401 * reimplemented the implicit simpset and claset using the new anytype
  5402 data filed in signatures; references simpset:simpset ref etc. are
  5403 replaced by functions simpset:unit->simpset and
  5404 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5405 to patch your ML files accordingly;
  5406 
  5407 * HTML output now includes theory graph data for display with Java
  5408 applet or isatool browser; data generated automatically via isatool
  5409 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5410 
  5411 * defs may now be conditional; improved rewrite_goals_tac to handle
  5412 conditional equations;
  5413 
  5414 * defs now admits additional type arguments, using TYPE('a) syntax;
  5415 
  5416 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5417 creates a new theory node; implicit merge of thms' signatures is
  5418 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5419 transfer:theory->thm->thm in (rare) cases;
  5420 
  5421 * improved handling of draft signatures / theories; draft thms (and
  5422 ctyps, cterms) are automatically promoted to real ones;
  5423 
  5424 * slightly changed interfaces for oracles: admit many per theory, named
  5425 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5426 
  5427 * print_goals: optional output of const types (set show_consts and
  5428 show_types);
  5429 
  5430 * improved output of warnings (###) and errors (***);
  5431 
  5432 * subgoal_tac displays a warning if the new subgoal has type variables;
  5433 
  5434 * removed old README and Makefiles;
  5435 
  5436 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5437 
  5438 * removed obsolete init_pps and init_database;
  5439 
  5440 * deleted the obsolete tactical STATE, which was declared by
  5441     fun STATE tacfun st = tacfun st st;
  5442 
  5443 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5444 (which abbreviates $HOME);
  5445 
  5446 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5447 use isatool fixseq to adapt your ML programs (this works for fully
  5448 qualified references to the Sequence structure only!);
  5449 
  5450 * use_thy no longer requires writable current directory; it always
  5451 reloads .ML *and* .thy file, if either one is out of date;
  5452 
  5453 
  5454 *** Classical Reasoner ***
  5455 
  5456 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5457 tactics that use classical reasoning to simplify a subgoal without
  5458 splitting it into several subgoals;
  5459 
  5460 * Safe_tac: like safe_tac but uses the default claset;
  5461 
  5462 
  5463 *** Simplifier ***
  5464 
  5465 * added simplification meta rules:
  5466     (asm_)(full_)simplify: simpset -> thm -> thm;
  5467 
  5468 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5469 logics (again);
  5470 
  5471 * added prems argument to simplification procedures;
  5472 
  5473 * HOL, FOL, ZF: added infix function `addsplits':
  5474   instead of `<simpset> setloop (split_tac <thms>)'
  5475   you can simply write `<simpset> addsplits <thms>'
  5476 
  5477 
  5478 *** Syntax ***
  5479 
  5480 * TYPE('a) syntax for type reflection terms;
  5481 
  5482 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5483 
  5484 * pretty printer: changed order of mixfix annotation preference (again!);
  5485 
  5486 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5487 
  5488 
  5489 *** HOL ***
  5490 
  5491 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5492   with `addloop' of the simplifier to faciliate case splitting in premises.
  5493 
  5494 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5495 
  5496 * HOL/Auth: new protocol proofs including some for the Internet
  5497   protocol TLS;
  5498 
  5499 * HOL/Map: new theory of `maps' a la VDM;
  5500 
  5501 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5502 cancelling out common nat summands from =, <, <= (in)equalities, or
  5503 differences; simplification procedures nat_cancel_factor for
  5504 cancelling common factor from =, <, <= (in)equalities over natural
  5505 sums; nat_cancel contains both kinds of procedures, it is installed by
  5506 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5507 
  5508 * HOL/simplifier: terms of the form
  5509   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5510   are rewritten to
  5511   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5512   and those of the form
  5513   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5514   are rewritten to
  5515   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5516 
  5517 * HOL/datatype
  5518   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5519 
  5520   P(t_case f1 ... fn x) =
  5521      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5522         ...
  5523        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5524      )
  5525 
  5526   and a theorem `split_t_case_asm' of the form
  5527 
  5528   P(t_case f1 ... fn x) =
  5529     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5530         ...
  5531        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5532      )
  5533   which can be added to a simpset via `addsplits'. The existing theorems
  5534   expand_list_case and expand_option_case have been renamed to
  5535   split_list_case and split_option_case.
  5536 
  5537 * HOL/Arithmetic:
  5538   - `pred n' is automatically converted to `n-1'.
  5539     Users are strongly encouraged not to use `pred' any longer,
  5540     because it will disappear altogether at some point.
  5541   - Users are strongly encouraged to write "0 < n" rather than
  5542     "n ~= 0". Theorems and proof tools have been modified towards this
  5543     `standard'.
  5544 
  5545 * HOL/Lists:
  5546   the function "set_of_list" has been renamed "set" (and its theorems too);
  5547   the function "nth" now takes its arguments in the reverse order and
  5548   has acquired the infix notation "!" as in "xs!n".
  5549 
  5550 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5551 
  5552 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5553   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5554 
  5555 * HOL/record: extensible records with schematic structural subtyping
  5556 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5557 still lacks various theorems and concrete record syntax;
  5558 
  5559 
  5560 *** HOLCF ***
  5561 
  5562 * removed "axioms" and "generated by" sections;
  5563 
  5564 * replaced "ops" section by extended "consts" section, which is capable of
  5565   handling the continuous function space "->" directly;
  5566 
  5567 * domain package:
  5568   . proves theorems immediately and stores them in the theory,
  5569   . creates hierachical name space,
  5570   . now uses normal mixfix annotations (instead of cinfix...),
  5571   . minor changes to some names and values (for consistency),
  5572   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5573   . separator between mutual domain defs: changed "," to "and",
  5574   . improved handling of sort constraints;  now they have to
  5575     appear on the left-hand side of the equations only;
  5576 
  5577 * fixed LAM <x,y,zs>.b syntax;
  5578 
  5579 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5580 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5581 
  5582 
  5583 *** FOL and ZF ***
  5584 
  5585 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5586   with `addloop' of the simplifier to faciliate case splitting in premises.
  5587 
  5588 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5589 in HOL, they strip ALL and --> from proved theorems;
  5590 
  5591 
  5592 
  5593 New in Isabelle94-8 (May 1997)
  5594 ------------------------------
  5595 
  5596 *** General Changes ***
  5597 
  5598 * new utilities to build / run / maintain Isabelle etc. (in parts
  5599 still somewhat experimental); old Makefiles etc. still functional;
  5600 
  5601 * new 'Isabelle System Manual';
  5602 
  5603 * INSTALL text, together with ./configure and ./build scripts;
  5604 
  5605 * reimplemented type inference for greater efficiency, better error
  5606 messages and clean internal interface;
  5607 
  5608 * prlim command for dealing with lots of subgoals (an easier way of
  5609 setting goals_limit);
  5610 
  5611 
  5612 *** Syntax ***
  5613 
  5614 * supports alternative (named) syntax tables (parser and pretty
  5615 printer); internal interface is provided by add_modesyntax(_i);
  5616 
  5617 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5618 be used in conjunction with the Isabelle symbol font; uses the
  5619 "symbols" syntax table;
  5620 
  5621 * added token_translation interface (may translate name tokens in
  5622 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5623 the current print_mode); IMPORTANT: user print translation functions
  5624 are responsible for marking newly introduced bounds
  5625 (Syntax.mark_boundT);
  5626 
  5627 * token translations for modes "xterm" and "xterm_color" that display
  5628 names in bold, underline etc. or colors (which requires a color
  5629 version of xterm);
  5630 
  5631 * infixes may now be declared with names independent of their syntax;
  5632 
  5633 * added typed_print_translation (like print_translation, but may
  5634 access type of constant);
  5635 
  5636 
  5637 *** Classical Reasoner ***
  5638 
  5639 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5640 some limitations.  Blast_tac...
  5641   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5642   + ignores elimination rules that don't have the correct format
  5643         (the conclusion MUST be a formula variable)
  5644   + ignores types, which can make HOL proofs fail
  5645   + rules must not require higher-order unification, e.g. apply_type in ZF
  5646     [message "Function Var's argument not a bound variable" relates to this]
  5647   + its proof strategy is more general but can actually be slower
  5648 
  5649 * substitution with equality assumptions no longer permutes other
  5650 assumptions;
  5651 
  5652 * minor changes in semantics of addafter (now called addaltern); renamed
  5653 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5654 (and access functions for it);
  5655 
  5656 * improved combination of classical reasoner and simplifier:
  5657   + functions for handling clasimpsets
  5658   + improvement of addss: now the simplifier is called _after_ the
  5659     safe steps.
  5660   + safe variant of addss called addSss: uses safe simplifications
  5661     _during_ the safe steps. It is more complete as it allows multiple
  5662     instantiations of unknowns (e.g. with slow_tac).
  5663 
  5664 *** Simplifier ***
  5665 
  5666 * added interface for simplification procedures (functions that
  5667 produce *proven* rewrite rules on the fly, depending on current
  5668 redex);
  5669 
  5670 * ordering on terms as parameter (used for ordered rewriting);
  5671 
  5672 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5673 
  5674 * the solver is now split into a safe and an unsafe part.
  5675 This should be invisible for the normal user, except that the
  5676 functions setsolver and addsolver have been renamed to setSolver and
  5677 addSolver; added safe_asm_full_simp_tac;
  5678 
  5679 
  5680 *** HOL ***
  5681 
  5682 * a generic induction tactic `induct_tac' which works for all datatypes and
  5683 also for type `nat';
  5684 
  5685 * a generic case distinction tactic `exhaust_tac' which works for all
  5686 datatypes and also for type `nat';
  5687 
  5688 * each datatype comes with a function `size';
  5689 
  5690 * patterns in case expressions allow tuple patterns as arguments to
  5691 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5692 
  5693 * primrec now also works with type nat;
  5694 
  5695 * recdef: a new declaration form, allows general recursive functions to be
  5696 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5697 
  5698 * the constant for negation has been renamed from "not" to "Not" to
  5699 harmonize with FOL, ZF, LK, etc.;
  5700 
  5701 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5702 infinite lists;
  5703 
  5704 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5705 
  5706 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  5707 problems in commutative rings, using axiomatic type classes for + and *;
  5708 
  5709 * more examples in HOL/MiniML and HOL/Auth;
  5710 
  5711 * more default rewrite rules for quantifiers, union/intersection;
  5712 
  5713 * a new constant `arbitrary == @x.False';
  5714 
  5715 * HOLCF/IOA replaces old HOL/IOA;
  5716 
  5717 * HOLCF changes: derived all rules and arities
  5718   + axiomatic type classes instead of classes
  5719   + typedef instead of faking type definitions
  5720   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5721   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5722   + eliminated the types void, one, tr
  5723   + use unit lift and bool lift (with translations) instead of one and tr
  5724   + eliminated blift from Lift3.thy (use Def instead of blift)
  5725   all eliminated rules are derived as theorems --> no visible changes ;
  5726 
  5727 
  5728 *** ZF ***
  5729 
  5730 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5731 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5732 as ZF_cs addSIs [equalityI];
  5733 
  5734 
  5735 
  5736 New in Isabelle94-7 (November 96)
  5737 ---------------------------------
  5738 
  5739 * allowing negative levels (as offsets) in prlev and choplev;
  5740 
  5741 * super-linear speedup for large simplifications;
  5742 
  5743 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  5744 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  5745 FAIL); can suppress it using the command Delsimps (ex_simps @
  5746 all_simps); De Morgan laws are also now included, by default;
  5747 
  5748 * improved printing of ==>  :  ~:
  5749 
  5750 * new object-logic "Sequents" adds linear logic, while replacing LK
  5751 and Modal (thanks to Sara Kalvala);
  5752 
  5753 * HOL/Auth: correctness proofs for authentication protocols;
  5754 
  5755 * HOL: new auto_tac combines rewriting and classical reasoning (many
  5756 examples on HOL/Auth);
  5757 
  5758 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  5759 the rewriter and classical reasoner simultaneously;
  5760 
  5761 * function uresult no longer returns theorems in "standard" format;
  5762 regain previous version by: val uresult = standard o uresult;
  5763 
  5764 
  5765 
  5766 New in Isabelle94-6
  5767 -------------------
  5768 
  5769 * oracles -- these establish an interface between Isabelle and trusted
  5770 external reasoners, which may deliver results as theorems;
  5771 
  5772 * proof objects (in particular record all uses of oracles);
  5773 
  5774 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  5775 
  5776 * "constdefs" section in theory files;
  5777 
  5778 * "primrec" section (HOL) no longer requires names;
  5779 
  5780 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  5781 
  5782 
  5783 
  5784 New in Isabelle94-5
  5785 -------------------
  5786 
  5787 * reduced space requirements;
  5788 
  5789 * automatic HTML generation from theories;
  5790 
  5791 * theory files no longer require "..." (quotes) around most types;
  5792 
  5793 * new examples, including two proofs of the Church-Rosser theorem;
  5794 
  5795 * non-curried (1994) version of HOL is no longer distributed;
  5796 
  5797 
  5798 
  5799 New in Isabelle94-4
  5800 -------------------
  5801 
  5802 * greatly reduced space requirements;
  5803 
  5804 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5805 
  5806 * searchable theorem database (see the section "Retrieving theorems" on
  5807 page 8 of the Reference Manual);
  5808 
  5809 * new examples, including Grabczewski's monumental case study of the
  5810 Axiom of Choice;
  5811 
  5812 * The previous version of HOL renamed to Old_HOL;
  5813 
  5814 * The new version of HOL (previously called CHOL) uses a curried syntax
  5815 for functions.  Application looks like f a b instead of f(a,b);
  5816 
  5817 * Mutually recursive inductive definitions finally work in HOL;
  5818 
  5819 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5820 translates to the operator "split";
  5821 
  5822 
  5823 
  5824 New in Isabelle94-3
  5825 -------------------
  5826 
  5827 * new infix operator, addss, allowing the classical reasoner to
  5828 perform simplification at each step of its search.  Example:
  5829         fast_tac (cs addss ss)
  5830 
  5831 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5832 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5833 look like (a,b) instead of <a,b>;
  5834 
  5835 * PLEASE NOTE: CHOL will eventually replace HOL!
  5836 
  5837 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5838 It translates to the operator "split".  A new theory of integers is available;
  5839 
  5840 * In ZF, integer numerals now denote two's-complement binary integers.
  5841 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5842 
  5843 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5844 of the Axiom of Choice;
  5845 
  5846 
  5847 
  5848 New in Isabelle94-2
  5849 -------------------
  5850 
  5851 * Significantly faster resolution;
  5852 
  5853 * the different sections in a .thy file can now be mixed and repeated
  5854 freely;
  5855 
  5856 * Database of theorems for FOL, HOL and ZF.  New
  5857 commands including qed, qed_goal and bind_thm store theorems in the database.
  5858 
  5859 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5860 a given theory (thms_of), or find out what theory a theorem was proved in
  5861 (theory_of_thm);
  5862 
  5863 * Bugs fixed in the inductive definition and datatype packages;
  5864 
  5865 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5866 and HOL_dup_cs obsolete;
  5867 
  5868 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5869 have been removed;
  5870 
  5871 * Simpler definition of function space in ZF;
  5872 
  5873 * new results about cardinal and ordinal arithmetic in ZF;
  5874 
  5875 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5876 types;
  5877 
  5878 :mode=text:wrap=hard:maxLineLen=72:
  5879 
  5880 
  5881 $Id$