NEWS
author haftmann
Fri Sep 26 09:10:02 2008 +0200 (2008-09-26)
changeset 28370 37f56e6e702d
parent 28350 715163ec93c0
child 28474 d0b8b0a1fca5
permissions -rw-r--r--
removed obsolete name convention "func"
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * The Isabelle System Manual (system) has been updated, with formally
    10 checked references as hyperlinks.
    11 
    12 * Generalized Isar history, with support for linear undo, direct state
    13 addressing etc.
    14 
    15 * Recovered hiding of consts, which was accidentally broken in
    16 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
    17 makes c inaccessible; consider using ``hide (open) const c'' instead.
    18 
    19 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
    20 interface instead.
    21 
    22 
    23 *** Pure ***
    24 
    25 * Changed defaults for unify configuration options:
    26 
    27   unify_trace_bound = 50 (formerly 25)
    28   unify_search_bound = 60 (formerly 30)
    29 
    30 * Different bookkeeping for code equations:
    31   a) On theory merge, the last set of code equations for a particular constant
    32      is taken (in accordance with the policy applied by other parts of the
    33      code generator framework).
    34   b) Code equations stemming from explicit declarations (e.g. code attribute)
    35      gain priority over default code equations stemming from definition, primrec,
    36      fun etc.
    37   INCOMPATIBILITY.
    38 
    39 * Global versions of theorems stemming from classes do not carry
    40 a parameter prefix any longer.  INCOMPATIBILITY.
    41 
    42 * Dropped "locale (open)".  INCOMPATBILITY.
    43 
    44 * Interpretation commands no longer attempt to simplify goal.
    45 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
    46 methods intro_locales and unfold_locales to clarify.
    47 
    48 * Interpretation commands no longer accept interpretation attributes.
    49 INCOMPATBILITY.
    50 
    51 * Command 'instance': attached definitions no longer accepted.
    52 INCOMPATIBILITY, use proper 'instantiation' target.
    53 
    54 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
    55 
    56 * The 'axiomatization' command now only works within a global theory
    57 context.  INCOMPATIBILITY.
    58 
    59 
    60 *** Document preparation ***
    61 
    62 * Antiquotation @{lemma} now imitates a regular terminal proof,
    63 demanding keyword 'by' and supporting the full method expression
    64 syntax just like the Isar command 'by'.
    65 
    66 
    67 *** HOL ***
    68 
    69 * Normalization by evaluation now allows non-leftlinear equations.
    70 Declare with attribute [code nbe].
    71 
    72 * Command "value" now integrates different evaluation
    73 mechanisms.  The result of the first successful evaluation mechanism
    74 is printed.  In square brackets a particular named evaluation
    75 mechanisms may be specified (currently, [SML], [code] or [nbe]).  See
    76 further src/HOL/ex/Eval_Examples.thy.
    77 
    78 * HOL/Orderings: class "wellorder" moved here, with explicit induction
    79 rule "less_induct" as assumption.  For instantiation of "wellorder" by
    80 means of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.
    81 
    82 * HOL/Orderings: added class "preorder" as superclass of "order".
    83 INCOMPATIBILITY: Instantiation proofs for order, linorder
    84 etc. slightly changed.  Some theorems named order_class.* now named
    85 preorder_class.*.
    86 
    87 * HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
    88 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
    89 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
    90 of lemmas from Divides has been generalized from nat to class
    91 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
    92 renames resulting from duplicate elimination:
    93 
    94     dvd_def_mod ~>          dvd_eq_mod_eq_0
    95     zero_dvd_iff ~>         dvd_0_left_iff
    96     DIVISION_BY_ZERO_DIV ~> div_by_0
    97     DIVISION_BY_ZERO_MOD ~> mod_by_0
    98     mult_div ~>             div_mult_self2_is_id
    99     mult_mod ~>             mod_mult_self2_is_0
   100 
   101 * HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   102 zlcm (for int); carried together from various gcd/lcm developements in
   103 the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
   104 corresponding theorems renamed accordingly.  INCOMPATIBILY.  To
   105 recover tupled syntax, use syntax declarations like:
   106 
   107     hide (open) const gcd
   108     abbreviation gcd where
   109       "gcd == (%(a, b). GCD.gcd a b)"
   110     notation (output)
   111       GCD.gcd ("gcd '(_, _')")
   112 
   113 (analogously for lcm, zgcd, zlcm).
   114 
   115 * HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   116 
   117 * New ML antiquotation @{code}: takes constant as argument, generates
   118 corresponding code in background and inserts name of the corresponding
   119 resulting ML value/function/datatype constructor binding in place.
   120 All occurrences of @{code} with a single ML block are generated
   121 simultaneously.  Provides a generic and safe interface for
   122 instrumentalizing code generation.  See HOL/ex/Code_Antiq for a toy
   123 example, or HOL/Complex/ex/ReflectedFerrack for a more ambitious
   124 application.  In future you ought refrain from ad-hoc compiling
   125 generated SML code on the ML toplevel.  Note that (for technical
   126 reasons) @{code} cannot refer to constants for which user-defined
   127 serializations are set.  Refer to the corresponding ML counterpart
   128 directly in that cases.
   129 
   130 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   131 Complex_Main.thy remain as they are.
   132 
   133 * New image HOL-Plain provides a minimal HOL with the most important
   134 tools available (inductive, datatype, primrec, ...).  By convention
   135 the corresponding theory Plain should be ancestor of every further
   136 (library) theory.  Some library theories now have ancestor Plain
   137 (instead of Main), thus theory Main occasionally has to be imported
   138 explicitly.
   139 
   140 * The metis method now fails in the usual manner, rather than raising
   141 an exception, if it determines that it cannot prove the theorem.
   142 
   143 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   144 as the structured Isar versions "cases" and "induct", cf. the
   145 corresponding "cases" and "induct" attributes.  Mutual induction rules
   146 are now presented as a list of individual projections
   147 (e.g. foo_bar.inducts for types foo and bar); the old format with
   148 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   149 rare situations a different rule is selected --- notably nested tuple
   150 elimination instead of former prod.exhaust: use explicit (case_tac t
   151 rule: prod.exhaust) here.
   152 
   153 * Attributes "cases", "induct", "coinduct" support "del" option.
   154 
   155 * Removed fact "case_split_thm", which duplicates "case_split".
   156 
   157 * Command 'rep_datatype': instead of theorem names the command now
   158 takes a list of terms denoting the constructors of the type to be
   159 represented as datatype.  The characteristic theorems have to be
   160 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   161 have disappeared in favour of existing ones:
   162 
   163     unit_induct                 ~> unit.induct
   164     prod_induct                 ~> prod.induct
   165     sum_induct                  ~> sum.induct
   166     Suc_Suc_eq                  ~> nat.inject
   167     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   168 
   169 * Library/Nat_Infinity: added addition, numeral syntax and more
   170 instantiations for algebraic structures.  Removed some duplicate
   171 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   172 
   173 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   174 menu.
   175 
   176 
   177 *** HOL-Algebra ***
   178 
   179 * New locales for orders and lattices where the equivalence relation
   180   is not restricted to equality.  INCOMPATIBILITY: all order and
   181   lattice locales use a record structure with field eq for the
   182   equivalence.
   183 
   184 * New theory of factorial domains.
   185 
   186 * Units_l_inv and Units_r_inv are now simprules by default.
   187 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   188 and/or r_inv will now also require deletion of these lemmas.
   189 
   190 * Renamed the following theorems.  INCOMPATIBILITY.
   191 UpperD ~> Upper_memD
   192 LowerD ~> Lower_memD
   193 least_carrier ~> least_closed
   194 greatest_carrier ~> greatest_closed
   195 greatest_Lower_above ~> greatest_Lower_below
   196 one_zero ~> carrier_one_zero
   197 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   198 
   199 
   200 *** HOL-NSA ***
   201 
   202 * Created new image HOL-NSA, containing theories of nonstandard
   203 analysis which were previously part of HOL-Complex.  Entry point
   204 Hyperreal.thy remains valid, but theories formerly using
   205 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   206 
   207 
   208 *** ZF ***
   209 
   210 * Proof of Zorn's Lemma for partial orders.
   211 
   212 
   213 *** ML ***
   214 
   215 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   216 to 'a -> thm, while results are always tagged with an authentic oracle
   217 name.  The Isar command 'oracle' is now polymorphic, no argument type
   218 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   219 accordingly.  Note that extra performance may be gained by producing
   220 the cterm carefully, avoiding slow Thm.cterm_of.
   221 
   222 * ML bindings produced via Isar commands are stored within the Isar
   223 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   224 become thread-safe and work with undo as expected (concerning
   225 top-level bindings, not side-effects on global references).
   226 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   227 compiler at runtime; really global bindings need to be given outside a
   228 theory. [Poly/ML 5.2 or later]
   229 
   230 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   231 context. Top-level ML bindings are stored within the proof context in
   232 a purely sequential fashion, disregarding the nested proof structure.
   233 ML bindings introduced by 'ML_prf' are discarded at the end of the
   234 proof.  [Poly/ML 5.2 or later]
   235 
   236 * Generic Toplevel.add_hook interface allows to analyze the result of
   237 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   238 for theorem dependency output of transactions resulting in a new
   239 theory state.
   240 
   241 * Name bindings in higher specification mechanisms (notably
   242 LocalTheory.define, LocalTheory.note, and derived packages) are now
   243 formalized as type Name.binding, replacing old bstring.
   244 INCOMPATIBILITY, need to wrap strings via Name.binding function, see
   245 also Name.name_of.  Packages should pass name bindings given by the
   246 user to underlying specification mechanisms; this enables precise
   247 tracking of source positions, for example.
   248 
   249 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   250 LocalTheory.note etc.) now refer to the *full* internal name, not the
   251 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   252 
   253 * Rules and tactics that read instantiations (read_instantiate,
   254 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   255 context, which is required for parsing and type-checking.  Moreover,
   256 the variables are specified as plain indexnames, not string encodings
   257 thereof.  INCOMPATIBILITY.
   258 
   259 * Disposed old type and term read functions (Sign.read_def_typ,
   260 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   261 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   262 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   263 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   264 resort for legacy applications.
   265 
   266 * Antiquotations: block-structured compilation context indicated by
   267 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   268 
   269   @{let ?pat = term}                      - term abbreviation (HO matching)
   270   @{note name = fact}                     - fact abbreviation
   271   @{thm fact}                             - singleton fact (with attributes)
   272   @{thms fact}                            - general fact (with attributes)
   273   @{lemma prop by method}                 - singleton goal
   274   @{lemma prop by meth1 meth2}            - singleton goal
   275   @{lemma prop1 ... propN by method}      - general goal
   276   @{lemma prop1 ... propN by meth1 meth2} - general goal
   277   @{lemma (open) ...}                     - open derivation
   278 
   279 
   280 *** System ***
   281 
   282 * Multithreading for Poly/ML 5.1 is no longer supported, only for
   283 Poly/ML 5.2 or later.
   284 
   285 * The Isabelle "emacs" tool provides a specific interface to invoke
   286 Proof General / Emacs, with more explicit failure if that is not
   287 installed (the old isabelle-interface script silently falls back on
   288 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   289 installation location of the Proof General distribution.
   290 
   291 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   292 the Isabelle process into a JVM/Scala application.  See
   293 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   294 process wrapper has been discontinued.)
   295 
   296 * Status messages (with exact source position information) are
   297 emitted, if proper markup print mode is enabled.  This allows
   298 user-interface components to provide detailed feedback on internal
   299 prover operations.
   300 
   301 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   302 
   303 
   304 
   305 New in Isabelle2008 (June 2008)
   306 -------------------------------
   307 
   308 *** General ***
   309 
   310 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   311 and updated, with formally checked references as hyperlinks.
   312 
   313 * Theory loader: use_thy (and similar operations) no longer set the
   314 implicit ML context, which was occasionally hard to predict and in
   315 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   316 provides a proper context already.
   317 
   318 * Theory loader: old-style ML proof scripts being *attached* to a thy
   319 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   320 'use' within a theory file will do the job.
   321 
   322 * Name space merge now observes canonical order, i.e. the second space
   323 is inserted into the first one, while existing entries in the first
   324 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   325 swap theory imports.
   326 
   327 * Syntax: symbol \<chi> is now considered a letter.  Potential
   328 INCOMPATIBILITY in identifier syntax etc.
   329 
   330 * Outer syntax: string tokens no longer admit escaped white space,
   331 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   332 white space without escapes.
   333 
   334 * Outer syntax: string tokens may contain arbitrary character codes
   335 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   336 "foo_bar".
   337 
   338 
   339 *** Pure ***
   340 
   341 * Context-dependent token translations.  Default setup reverts locally
   342 fixed variables, and adds hilite markup for undeclared frees.
   343 
   344 * Unused theorems can be found using the new command 'unused_thms'.
   345 There are three ways of invoking it:
   346 
   347 (1) unused_thms
   348      Only finds unused theorems in the current theory.
   349 
   350 (2) unused_thms thy_1 ... thy_n -
   351      Finds unused theorems in the current theory and all of its ancestors,
   352      excluding the theories thy_1 ... thy_n and all of their ancestors.
   353 
   354 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   355      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   356      their ancestors, excluding the theories thy_1 ... thy_n and all of
   357      their ancestors.
   358 
   359 In order to increase the readability of the list produced by
   360 unused_thms, theorems that have been created by a particular instance
   361 of a theory command such as 'inductive' or 'function' are considered
   362 to belong to the same "group", meaning that if at least one theorem in
   363 this group is used, the other theorems in the same group are no longer
   364 reported as unused.  Moreover, if all theorems in the group are
   365 unused, only one theorem in the group is displayed.
   366 
   367 Note that proof objects have to be switched on in order for
   368 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   369 usually the case when using Proof General with the default settings).
   370 
   371 * Authentic naming of facts disallows ad-hoc overwriting of previous
   372 theorems within the same name space.  INCOMPATIBILITY, need to remove
   373 duplicate fact bindings, or even accidental fact duplications.  Note
   374 that tools may maintain dynamically scoped facts systematically, using
   375 PureThy.add_thms_dynamic.
   376 
   377 * Command 'hide' now allows to hide from "fact" name space as well.
   378 
   379 * Eliminated destructive theorem database, simpset, claset, and
   380 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   381 update of theories within ML code.
   382 
   383 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   384 INCOMPATIBILITY, object-logics depending on former Pure require
   385 additional setup PureThy.old_appl_syntax_setup; object-logics
   386 depending on former CPure need to refer to Pure.
   387 
   388 * Commands 'use' and 'ML' are now purely functional, operating on
   389 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   390 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   391 INCOMPATIBILITY.
   392 
   393 * Command 'setup': discontinued implicit version with ML reference.
   394 
   395 * Instantiation target allows for simultaneous specification of class
   396 instance operations together with an instantiation proof.
   397 Type-checking phase allows to refer to class operations uniformly.
   398 See src/HOL/Complex/Complex.thy for an Isar example and
   399 src/HOL/Library/Eval.thy for an ML example.
   400 
   401 * Indexing of literal facts: be more serious about including only
   402 facts from the visible specification/proof context, but not the
   403 background context (locale etc.).  Affects `prop` notation and method
   404 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   405 situations.
   406 
   407 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   408 "(open)" option, which used to expose internal bound variables to the
   409 proof text.
   410 
   411 * Isar statements: removed obsolete case "rule_context".
   412 INCOMPATIBILITY, better use explicit fixes/assumes.
   413 
   414 * Locale proofs: default proof step now includes 'unfold_locales';
   415 hence 'proof' without argument may be used to unfold locale
   416 predicates.
   417 
   418 
   419 *** Document preparation ***
   420 
   421 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   422 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   423 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   424 spot); renamed link color from "darkblue" to "linkcolor" (default
   425 value unchanged, can be redefined via \definecolor); no longer sets
   426 "a4paper" option (unnecessary or even intrusive).
   427 
   428 * Antiquotation @{lemma A method} proves proposition A by the given
   429 method (either a method name or a method name plus (optional) method
   430 arguments in parentheses) and prints A just like @{prop A}.
   431 
   432 
   433 *** HOL ***
   434 
   435 * New primrec package.  Specification syntax conforms in style to
   436 definition/function/....  No separate induction rule is provided.  The
   437 "primrec" command distinguishes old-style and new-style specifications
   438 by syntax.  The former primrec package is now named OldPrimrecPackage.
   439 When adjusting theories, beware: constants stemming from new-style
   440 primrec specifications have authentic syntax.
   441 
   442 * Metis prover is now an order of magnitude faster, and also works
   443 with multithreading.
   444 
   445 * Metis: the maximum number of clauses that can be produced from a
   446 theorem is now given by the attribute max_clauses.  Theorems that
   447 exceed this number are ignored, with a warning printed.
   448 
   449 * Sledgehammer no longer produces structured proofs by default. To
   450 enable, declare [[sledgehammer_full = true]].  Attributes
   451 reconstruction_modulus, reconstruction_sorts renamed
   452 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   453 
   454 * Method "induct_scheme" derives user-specified induction rules
   455 from well-founded induction and completeness of patterns. This factors
   456 out some operations that are done internally by the function package
   457 and makes them available separately.  See
   458 src/HOL/ex/Induction_Scheme.thy for examples.
   459 
   460 * More flexible generation of measure functions for termination
   461 proofs: Measure functions can be declared by proving a rule of the
   462 form "is_measure f" and giving it the [measure_function] attribute.
   463 The "is_measure" predicate is logically meaningless (always true), and
   464 just guides the heuristic.  To find suitable measure functions, the
   465 termination prover sets up the goal "is_measure ?f" of the appropriate
   466 type and generates all solutions by prolog-style backwards proof using
   467 the declared rules.
   468 
   469 This setup also deals with rules like 
   470 
   471   "is_measure f ==> is_measure (list_size f)"
   472 
   473 which accommodates nested datatypes that recurse through lists.
   474 Similar rules are predeclared for products and option types.
   475 
   476 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   477 
   478   INCOMPATIBILITIES:
   479 
   480   - Definitions of overloaded constants on sets have to be replaced by
   481     definitions on => and bool.
   482 
   483   - Some definitions of overloaded operators on sets can now be proved
   484     using the definitions of the operators on => and bool.  Therefore,
   485     the following theorems have been renamed:
   486 
   487       subset_def   -> subset_eq
   488       psubset_def  -> psubset_eq
   489       set_diff_def -> set_diff_eq
   490       Compl_def    -> Compl_eq
   491       Sup_set_def  -> Sup_set_eq
   492       Inf_set_def  -> Inf_set_eq
   493       sup_set_def  -> sup_set_eq
   494       inf_set_def  -> inf_set_eq
   495 
   496   - Due to the incompleteness of the HO unification algorithm, some
   497     rules such as subst may require manual instantiation, if some of
   498     the unknowns in the rule is a set.
   499 
   500   - Higher order unification and forward proofs:
   501     The proof pattern
   502 
   503       have "P (S::'a set)" <...>
   504       then have "EX S. P S" ..
   505 
   506     no longer works (due to the incompleteness of the HO unification
   507     algorithm) and must be replaced by the pattern
   508 
   509       have "EX S. P S"
   510       proof
   511         show "P S" <...>
   512       qed
   513 
   514   - Calculational reasoning with subst (or similar rules):
   515     The proof pattern
   516 
   517       have "P (S::'a set)" <...>
   518       also have "S = T" <...>
   519       finally have "P T" .
   520 
   521     no longer works (for similar reasons as the previous example) and
   522     must be replaced by something like
   523 
   524       have "P (S::'a set)" <...>
   525       moreover have "S = T" <...>
   526       ultimately have "P T" by simp
   527 
   528   - Tactics or packages written in ML code:
   529     Code performing pattern matching on types via
   530 
   531       Type ("set", [T]) => ...
   532 
   533     must be rewritten. Moreover, functions like strip_type or
   534     binder_types no longer return the right value when applied to a
   535     type of the form
   536 
   537       T1 => ... => Tn => U => bool
   538 
   539     rather than
   540 
   541       T1 => ... => Tn => U set
   542 
   543 * Merged theories Wellfounded_Recursion, Accessible_Part and
   544 Wellfounded_Relations to theory Wellfounded.
   545 
   546 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   547 
   548 * Class finite no longer treats UNIV as class parameter.  Use class
   549 enum from theory Library/Enum instead to achieve a similar effect.
   550 INCOMPATIBILITY.
   551 
   552 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   553 and "Cons".  INCOMPATIBILITY.
   554 
   555 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   556 Potential INCOMPATIBILITY.
   557 
   558 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   559 injective_fst_snd removed, use split_eta and prod_eqI instead.
   560 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   561 
   562 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   563 the same name in theory Orderings:
   564 
   565   less_trans
   566   less_linear
   567   le_imp_less_or_eq
   568   le_less_trans
   569   less_le_trans
   570   less_not_sym
   571   less_asym
   572 
   573 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
   574 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
   575 and different variable names.
   576 
   577 * Library/Option_ord.thy: Canonical order on option type.
   578 
   579 * Library/RBT.thy: Red-black trees, an efficient implementation of
   580 finite maps.
   581 
   582 * Library/Countable.thy: Type class for countable types.
   583 
   584 * Theory Int: The representation of numerals has changed.  The infix
   585 operator BIT and the bit datatype with constructors B0 and B1 have
   586 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
   587 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
   588 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
   589 accordingly.
   590 
   591 * Theory Nat: definition of <= and < on natural numbers no longer
   592 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
   593 le_def and less_def have disappeared.  Consider lemmas not_less
   594 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
   595 
   596 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
   597 (whose purpose mainly is for various fold_set functionals) have been
   598 abandoned in favor of the existing algebraic classes
   599 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
   600 lower_semilattice (resp. upper_semilattice) and linorder.
   601 INCOMPATIBILITY.
   602 
   603 * Theory Transitive_Closure: induct and cases rules now declare proper
   604 case_names ("base" and "step").  INCOMPATIBILITY.
   605 
   606 * Theorem Inductive.lfp_ordinal_induct generalized to complete
   607 lattices.  The form set-specific version is available as
   608 Inductive.lfp_ordinal_induct_set.
   609 
   610 * Renamed theorems "power.simps" to "power_int.simps".
   611 INCOMPATIBILITY.
   612 
   613 * Class semiring_div provides basic abstract properties of semirings
   614 with division and modulo operations.  Subsumes former class dvd_mod.
   615 
   616 * Merged theories IntDef, Numeral and IntArith into unified theory
   617 Int.  INCOMPATIBILITY.
   618 
   619 * Theory Library/Code_Index: type "index" now represents natural
   620 numbers rather than integers.  INCOMPATIBILITY.
   621 
   622 * New class "uminus" with operation "uminus" (split of from class
   623 "minus" which now only has operation "minus", binary).
   624 INCOMPATIBILITY.
   625 
   626 * Constants "card", "internal_split", "option_map" now with authentic
   627 syntax.  INCOMPATIBILITY.
   628 
   629 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
   630 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
   631 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
   632 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
   633 Sup_set_def, le_def, less_def, option_map_def now with object
   634 equality.  INCOMPATIBILITY.
   635 
   636 * Records. Removed K_record, and replaced it by pure lambda term
   637 %x. c. The simplifier setup is now more robust against eta expansion.
   638 INCOMPATIBILITY: in cases explicitly referring to K_record.
   639 
   640 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
   641 
   642 * Library/ListVector: new theory of arithmetic vector operations.
   643 
   644 * Library/Order_Relation: new theory of various orderings as sets of
   645 pairs.  Defines preorders, partial orders, linear orders and
   646 well-orders on sets and on types.
   647 
   648 
   649 *** ZF ***
   650 
   651 * Renamed some theories to allow to loading both ZF and HOL in the
   652 same session:
   653 
   654   Datatype  -> Datatype_ZF
   655   Inductive -> Inductive_ZF
   656   Int       -> Int_ZF
   657   IntDiv    -> IntDiv_ZF
   658   Nat       -> Nat_ZF
   659   List      -> List_ZF
   660   Main      -> Main_ZF
   661 
   662 INCOMPATIBILITY: ZF theories that import individual theories below
   663 Main might need to be adapted.  Regular theory Main is still
   664 available, as trivial extension of Main_ZF.
   665 
   666 
   667 *** ML ***
   668 
   669 * ML within Isar: antiquotation @{const name} or @{const
   670 name(typargs)} produces statically-checked Const term.
   671 
   672 * Functor NamedThmsFun: data is available to the user as dynamic fact
   673 (of the same name).  Removed obsolete print command.
   674 
   675 * Removed obsolete "use_legacy_bindings" function.
   676 
   677 * The ``print mode'' is now a thread-local value derived from a global
   678 template (the former print_mode reference), thus access becomes
   679 non-critical.  The global print_mode reference is for session
   680 management only; user-code should use print_mode_value,
   681 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
   682 
   683 * Functions system/system_out provide a robust way to invoke external
   684 shell commands, with propagation of interrupts (requires Poly/ML 5.2).
   685 Do not use OS.Process.system etc. from the basis library!
   686 
   687 
   688 *** System ***
   689 
   690 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
   691 in accordance with Proof General 3.7, which prefers GNU emacs.
   692 
   693 * isatool tty runs Isabelle process with plain tty interaction;
   694 optional line editor may be specified via ISABELLE_LINE_EDITOR
   695 setting, the default settings attempt to locate "ledit" and "rlwrap".
   696 
   697 * isatool browser now works with Cygwin as well, using general
   698 "javapath" function defined in Isabelle process environment.
   699 
   700 * YXML notation provides a simple and efficient alternative to
   701 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
   702 isatool yxml as described in the Isabelle system manual.
   703 
   704 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
   705 provides general wrapper for managing an Isabelle process in a robust
   706 fashion, with ``cooked'' output from stdin/stderr.
   707 
   708 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
   709 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
   710 
   711 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
   712 way of changing the user's settings is via
   713 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
   714 script.
   715 
   716 * Multithreading.max_threads := 0 refers to the number of actual CPU
   717 cores of the underlying machine, which is a good starting point for
   718 optimal performance tuning.  The corresponding usedir option -M allows
   719 "max" as an alias for "0".  WARNING: does not work on certain versions
   720 of Mac OS (with Poly/ML 5.1).
   721 
   722 * isabelle-process: non-ML sessions are run with "nice", to reduce the
   723 adverse effect of Isabelle flooding interactive front-ends (notably
   724 ProofGeneral / XEmacs).
   725 
   726 
   727 
   728 New in Isabelle2007 (November 2007)
   729 -----------------------------------
   730 
   731 *** General ***
   732 
   733 * More uniform information about legacy features, notably a
   734 warning/error of "Legacy feature: ...", depending on the state of the
   735 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
   736 legacy features will disappear eventually.
   737 
   738 * Theory syntax: the header format ``theory A = B + C:'' has been
   739 discontinued in favour of ``theory A imports B C begin''.  Use isatool
   740 fixheaders to convert existing theory files.  INCOMPATIBILITY.
   741 
   742 * Theory syntax: the old non-Isar theory file format has been
   743 discontinued altogether.  Note that ML proof scripts may still be used
   744 with Isar theories; migration is usually quite simple with the ML
   745 function use_legacy_bindings.  INCOMPATIBILITY.
   746 
   747 * Theory syntax: some popular names (e.g. 'class', 'declaration',
   748 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
   749 quotes.
   750 
   751 * Theory loader: be more serious about observing the static theory
   752 header specifications (including optional directories), but not the
   753 accidental file locations of previously successful loads.  The strict
   754 update policy of former update_thy is now already performed by
   755 use_thy, so the former has been removed; use_thys updates several
   756 theories simultaneously, just as 'imports' within a theory header
   757 specification, but without merging the results.  Potential
   758 INCOMPATIBILITY: may need to refine theory headers and commands
   759 ROOT.ML which depend on load order.
   760 
   761 * Theory loader: optional support for content-based file
   762 identification, instead of the traditional scheme of full physical
   763 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
   764 (cf. the system manual).  The new scheme allows to work with
   765 non-finished theories in persistent session images, such that source
   766 files may be moved later on without requiring reloads.
   767 
   768 * Theory loader: old-style ML proof scripts being *attached* to a thy
   769 file (with the same base name as the theory) are considered a legacy
   770 feature, which will disappear eventually. Even now, the theory loader
   771 no longer maintains dependencies on such files.
   772 
   773 * Syntax: the scope for resolving ambiguities via type-inference is
   774 now limited to individual terms, instead of whole simultaneous
   775 specifications as before. This greatly reduces the complexity of the
   776 syntax module and improves flexibility by separating parsing and
   777 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
   778 'fixes' etc.) are required in rare situations.
   779 
   780 * Syntax: constants introduced by new-style packages ('definition',
   781 'abbreviation' etc.) are passed through the syntax module in
   782 ``authentic mode''. This means that associated mixfix annotations
   783 really stick to such constants, independently of potential name space
   784 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
   785 trees are represented slightly differently, may need to adapt syntax
   786 translations accordingly. Use CONST marker in 'translations' and
   787 @{const_syntax} antiquotation in 'parse_translation' etc.
   788 
   789 * Legacy goal package: reduced interface to the bare minimum required
   790 to keep existing proof scripts running.  Most other user-level
   791 functions are now part of the OldGoals structure, which is *not* open
   792 by default (consider isatool expandshort before open OldGoals).
   793 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
   794 these tend to cause confusion about the actual goal (!) context being
   795 used here, which is not necessarily the same as the_context().
   796 
   797 * Command 'find_theorems': supports "*" wild-card in "name:"
   798 criterion; "with_dups" option.  Certain ProofGeneral versions might
   799 support a specific search form (see ProofGeneral/CHANGES).
   800 
   801 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
   802 by default, which means that "prems" (and also "fixed variables") are
   803 suppressed from proof state output.  Note that the ProofGeneral
   804 settings mechanism allows to change and save options persistently, but
   805 older versions of Isabelle will fail to start up if a negative prems
   806 limit is imposed.
   807 
   808 * Local theory targets may be specified by non-nested blocks of
   809 ``context/locale/class ... begin'' followed by ``end''.  The body may
   810 contain definitions, theorems etc., including any derived mechanism
   811 that has been implemented on top of these primitives.  This concept
   812 generalizes the existing ``theorem (in ...)'' towards more versatility
   813 and scalability.
   814 
   815 * Proof General interface: proper undo of final 'end' command;
   816 discontinued Isabelle/classic mode (ML proof scripts).
   817 
   818 
   819 *** Document preparation ***
   820 
   821 * Added antiquotation @{theory name} which prints the given name,
   822 after checking that it refers to a valid ancestor theory in the
   823 current context.
   824 
   825 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   826 check the given source text as ML type/structure, printing verbatim.
   827 
   828 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   829 "c args == rhs" given in the current context.  (Any number of
   830 arguments may be given on the LHS.)
   831 
   832 
   833 *** Pure ***
   834 
   835 * The 'class' package offers a combination of axclass and locale to
   836 achieve Haskell-like type classes in Isabelle.  Definitions and
   837 theorems within a class context produce both relative results (with
   838 implicit parameters according to the locale context), and polymorphic
   839 constants with qualified polymorphism (according to the class
   840 context).  Within the body context of a 'class' target, a separate
   841 syntax layer ("user space type system") takes care of converting
   842 between global polymorphic consts and internal locale representation.
   843 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   844 "isatool doc classes" provides a tutorial.
   845 
   846 * Generic code generator framework allows to generate executable
   847 code for ML and Haskell (including Isabelle classes).  A short usage
   848 sketch:
   849 
   850     internal compilation:
   851         export_code <list of constants (term syntax)> in SML
   852     writing SML code to a file:
   853         export_code <list of constants (term syntax)> in SML <filename>
   854     writing OCaml code to a file:
   855         export_code <list of constants (term syntax)> in OCaml <filename>
   856     writing Haskell code to a bunch of files:
   857         export_code <list of constants (term syntax)> in Haskell <filename>
   858 
   859     evaluating closed propositions to True/False using code generation:
   860         method ``eval''
   861 
   862 Reasonable default setup of framework in HOL.
   863 
   864 Theorem attributs for selecting and transforming function equations theorems:
   865 
   866     [code fun]:        select a theorem as function equation for a specific constant
   867     [code fun del]:    deselect a theorem as function equation for a specific constant
   868     [code inline]:     select an equation theorem for unfolding (inlining) in place
   869     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   870 
   871 User-defined serializations (target in {SML, OCaml, Haskell}):
   872 
   873     code_const <and-list of constants (term syntax)>
   874       {(target) <and-list of const target syntax>}+
   875 
   876     code_type <and-list of type constructors>
   877       {(target) <and-list of type target syntax>}+
   878 
   879     code_instance <and-list of instances>
   880       {(target)}+
   881         where instance ::= <type constructor> :: <class>
   882 
   883     code_class <and_list of classes>
   884       {(target) <and-list of class target syntax>}+
   885         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   886 
   887 code_instance and code_class only are effective to target Haskell.
   888 
   889 For example usage see src/HOL/ex/Codegenerator.thy and
   890 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   891 generation from Isabelle/HOL theories is available via "isatool doc
   892 codegen".
   893 
   894 * Code generator: consts in 'consts_code' Isar commands are now
   895 referred to by usual term syntax (including optional type
   896 annotations).
   897 
   898 * Command 'no_translations' removes translation rules from theory
   899 syntax.
   900 
   901 * Overloaded definitions are now actually checked for acyclic
   902 dependencies.  The overloading scheme is slightly more general than
   903 that of Haskell98, although Isabelle does not demand an exact
   904 correspondence to type class and instance declarations.
   905 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   906 exotic versions of overloading -- at the discretion of the user!
   907 
   908 Polymorphic constants are represented via type arguments, i.e. the
   909 instantiation that matches an instance against the most general
   910 declaration given in the signature.  For example, with the declaration
   911 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   912 as c(nat).  Overloading is essentially simultaneous structural
   913 recursion over such type arguments.  Incomplete specification patterns
   914 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   915 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   916 Command 'print_theory' outputs the normalized system of recursive
   917 equations, see section "definitions".
   918 
   919 * Configuration options are maintained within the theory or proof
   920 context (with name and type bool/int/string), providing a very simple
   921 interface to a poor-man's version of general context data.  Tools may
   922 declare options in ML (e.g. using Attrib.config_int) and then refer to
   923 these values using Config.get etc.  Users may change options via an
   924 associated attribute of the same name.  This form of context
   925 declaration works particularly well with commands 'declare' or
   926 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   927 very easy to avoid global references, which would not observe Isar
   928 toplevel undo/redo and fail to work with multithreading.
   929 
   930 Various global ML references of Pure and HOL have been turned into
   931 configuration options:
   932 
   933   Unify.search_bound		unify_search_bound
   934   Unify.trace_bound		unify_trace_bound
   935   Unify.trace_simp		unify_trace_simp
   936   Unify.trace_types		unify_trace_types
   937   Simplifier.simp_depth_limit	simp_depth_limit
   938   Blast.depth_limit		blast_depth_limit
   939   DatatypeProp.dtK		datatype_distinctness_limit
   940   fast_arith_neq_limit  	fast_arith_neq_limit
   941   fast_arith_split_limit	fast_arith_split_limit
   942 
   943 * Named collections of theorems may be easily installed as context
   944 data using the functor NamedThmsFun (see also
   945 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   946 attributes; there is also a toplevel print command.  This facility is
   947 just a common case of general context data, which is the preferred way
   948 for anything more complex than just a list of facts in canonical
   949 order.
   950 
   951 * Isar: command 'declaration' augments a local theory by generic
   952 declaration functions written in ML.  This enables arbitrary content
   953 being added to the context, depending on a morphism that tells the
   954 difference of the original declaration context wrt. the application
   955 context encountered later on.
   956 
   957 * Isar: proper interfaces for simplification procedures.  Command
   958 'simproc_setup' declares named simprocs (with match patterns, and body
   959 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   960 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   961 
   962 * Isar: an extra pair of brackets around attribute declarations
   963 abbreviates a theorem reference involving an internal dummy fact,
   964 which will be ignored later --- only the effect of the attribute on
   965 the background context will persist.  This form of in-place
   966 declarations is particularly useful with commands like 'declare' and
   967 'using', for example ``have A using [[simproc a]] by simp''.
   968 
   969 * Isar: method "assumption" (and implicit closing of subproofs) now
   970 takes simple non-atomic goal assumptions into account: after applying
   971 an assumption as a rule the resulting subgoals are solved by atomic
   972 assumption steps.  This is particularly useful to finish 'obtain'
   973 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   974 without referring to the original premise "!!x. P x ==> thesis" in the
   975 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   976 more permissive.
   977 
   978 * Isar: implicit use of prems from the Isar proof context is
   979 considered a legacy feature.  Common applications like ``have A .''
   980 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   981 referencing facts explicitly here improves readability and
   982 maintainability of proof texts.
   983 
   984 * Isar: improper proof element 'guess' is like 'obtain', but derives
   985 the obtained context from the course of reasoning!  For example:
   986 
   987   assume "EX x y. A x & B y"   -- "any previous fact"
   988   then guess x and y by clarify
   989 
   990 This technique is potentially adventurous, depending on the facts and
   991 proof tools being involved here.
   992 
   993 * Isar: known facts from the proof context may be specified as literal
   994 propositions, using ASCII back-quote syntax.  This works wherever
   995 named facts used to be allowed so far, in proof commands, proof
   996 methods, attributes etc.  Literal facts are retrieved from the context
   997 according to unification of type and term parameters.  For example,
   998 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   999 theorems in the current context, then these are valid literal facts:
  1000 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1001 
  1002 There is also a proof method "fact" which does the same composition
  1003 for explicit goal states, e.g. the following proof texts coincide with
  1004 certain special cases of literal facts:
  1005 
  1006   have "A" by fact                 ==  note `A`
  1007   have "A ==> B" by fact           ==  note `A ==> B`
  1008   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1009   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1010 
  1011 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1012 outer syntax.  Thus symbolic identifiers may be used without
  1013 additional white space in declarations like this: ``assume *: A''.
  1014 
  1015 * Isar: 'print_facts' prints all local facts of the current context,
  1016 both named and unnamed ones.
  1017 
  1018 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1019 
  1020   def x == "t" and y == "u"
  1021 
  1022 * Isar: added command 'unfolding', which is structurally similar to
  1023 'using', but affects both the goal state and facts by unfolding given
  1024 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1025 'unfolded' attribute may be replaced by first-class proof text.
  1026 
  1027 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1028 and command 'unfolding' now all support object-level equalities
  1029 (potentially conditional).  The underlying notion of rewrite rule is
  1030 analogous to the 'rule_format' attribute, but *not* that of the
  1031 Simplifier (which is usually more generous).
  1032 
  1033 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1034 premises of a theorem by n. Useful in conjunction with drule.
  1035 
  1036 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1037 method expression within a sandbox consisting of the first N
  1038 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1039 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1040 simplifies all new goals that emerge from applying rule foo to the
  1041 originally first one.
  1042 
  1043 * Isar: schematic goals are no longer restricted to higher-order
  1044 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1045 expected.
  1046 
  1047 * Isar: the conclusion of a long theorem statement is now either
  1048 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1049 (essentially a disjunction of cases with local parameters and
  1050 assumptions).  The latter allows to express general elimination rules
  1051 adequately; in this notation common elimination rules look like this:
  1052 
  1053   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1054     assumes "EX x. P x"
  1055     obtains x where "P x"
  1056 
  1057   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1058     assumes "A & B"
  1059     obtains A and B
  1060 
  1061   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1062     assumes "A | B"
  1063     obtains
  1064       A
  1065     | B
  1066 
  1067 The subsequent classical rules even refer to the formal "thesis"
  1068 explicitly:
  1069 
  1070   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1071     obtains "~ thesis"
  1072 
  1073   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1074     obtains "thesis ==> something"
  1075 
  1076 The actual proof of an 'obtains' statement is analogous to that of the
  1077 Isar proof element 'obtain', only that there may be several cases.
  1078 Optional case names may be specified in parentheses; these will be
  1079 available both in the present proof and as annotations in the
  1080 resulting rule, for later use with the 'cases' method (cf. attribute
  1081 case_names).
  1082 
  1083 * Isar: the assumptions of a long theorem statement are available as
  1084 "assms" fact in the proof context.  This is more appropriate than the
  1085 (historical) "prems", which refers to all assumptions of the current
  1086 context, including those from the target locale, proof body etc.
  1087 
  1088 * Isar: 'print_statement' prints theorems from the current theory or
  1089 proof context in long statement form, according to the syntax of a
  1090 top-level lemma.
  1091 
  1092 * Isar: 'obtain' takes an optional case name for the local context
  1093 introduction rule (default "that").
  1094 
  1095 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1096 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1097 to occur.
  1098 
  1099 * Pure: syntax "CONST name" produces a fully internalized constant
  1100 according to the current context.  This is particularly useful for
  1101 syntax translations that should refer to internal constant
  1102 representations independently of name spaces.
  1103 
  1104 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1105 instead of "FOO ". This allows multiple binder declarations to coexist
  1106 in the same context.  INCOMPATIBILITY.
  1107 
  1108 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1109 primitive that also works in a locale context (both for constants and
  1110 fixed variables). Type declaration and internal syntactic representation
  1111 of given constants retrieved from the context. Likewise, the
  1112 'no_notation' command allows to remove given syntax annotations from the
  1113 current context.
  1114 
  1115 * Isar/locales: new derived specification elements 'axiomatization',
  1116 'definition', 'abbreviation', which support type-inference, admit
  1117 object-level specifications (equality, equivalence).  See also the
  1118 isar-ref manual.  Examples:
  1119 
  1120   axiomatization
  1121     eq  (infix "===" 50) where
  1122     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1123 
  1124   definition "f x y = x + y + 1"
  1125   definition g where "g x = f x x"
  1126 
  1127   abbreviation
  1128     neq  (infix "=!=" 50) where
  1129     "x =!= y == ~ (x === y)"
  1130 
  1131 These specifications may be also used in a locale context.  Then the
  1132 constants being introduced depend on certain fixed parameters, and the
  1133 constant name is qualified by the locale base name.  An internal
  1134 abbreviation takes care for convenient input and output, making the
  1135 parameters implicit and using the original short name.  See also
  1136 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1137 entities from a monomorphic theory.
  1138 
  1139 Presently, abbreviations are only available 'in' a target locale, but
  1140 not inherited by general import expressions.  Also note that
  1141 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1142 'translations' in common applications.  The "no_abbrevs" print mode
  1143 prevents folding of abbreviations in term output.
  1144 
  1145 Concrete syntax is attached to specified constants in internal form,
  1146 independently of name spaces.  The parse tree representation is
  1147 slightly different -- use 'notation' instead of raw 'syntax', and
  1148 'translations' with explicit "CONST" markup to accommodate this.
  1149 
  1150 * Pure/Isar: unified syntax for new-style specification mechanisms
  1151 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1152 full type inference and dummy patterns ("_").  For example:
  1153 
  1154   definition "K x _ = x"
  1155 
  1156   inductive conj for A B
  1157   where "A ==> B ==> conj A B"
  1158 
  1159 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1160 the current context.  Print mode "no_abbrevs" prevents inversion of
  1161 abbreviations on output.
  1162 
  1163 * Isar/locales: improved parameter handling: use of locales "var" and
  1164 "struct" no longer necessary; - parameter renamings are no longer
  1165 required to be injective.  For example, this allows to define
  1166 endomorphisms as locale endom = homom mult mult h.
  1167 
  1168 * Isar/locales: changed the way locales with predicates are defined.
  1169 Instead of accumulating the specification, the imported expression is
  1170 now an interpretation.  INCOMPATIBILITY: different normal form of
  1171 locale expressions.  In particular, in interpretations of locales with
  1172 predicates, goals repesenting already interpreted fragments are not
  1173 removed automatically.  Use methods `intro_locales' and
  1174 `unfold_locales'; see below.
  1175 
  1176 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1177 provide backward reasoning on locales predicates.  The methods are
  1178 aware of interpretations and discharge corresponding goals.
  1179 `intro_locales' is less aggressive then `unfold_locales' and does not
  1180 unfold predicates to assumptions.
  1181 
  1182 * Isar/locales: the order in which locale fragments are accumulated
  1183 has changed.  This enables to override declarations from fragments due
  1184 to interpretations -- for example, unwanted simp rules.
  1185 
  1186 * Isar/locales: interpretation in theories and proof contexts has been
  1187 extended.  One may now specify (and prove) equations, which are
  1188 unfolded in interpreted theorems.  This is useful for replacing
  1189 defined concepts (constants depending on locale parameters) by
  1190 concepts already existing in the target context.  Example:
  1191 
  1192   interpretation partial_order ["op <= :: [int, int] => bool"]
  1193     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1194 
  1195 Typically, the constant `partial_order.less' is created by a
  1196 definition specification element in the context of locale
  1197 partial_order.
  1198 
  1199 * Method "induct": improved internal context management to support
  1200 local fixes and defines on-the-fly. Thus explicit meta-level
  1201 connectives !!  and ==> are rarely required anymore in inductive goals
  1202 (using object-logic connectives for this purpose has been long
  1203 obsolete anyway). Common proof patterns are explained in
  1204 src/HOL/Induct/Common_Patterns.thy, see also
  1205 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1206 examples.
  1207 
  1208 * Method "induct": improved handling of simultaneous goals. Instead of
  1209 introducing object-level conjunction, the statement is now split into
  1210 several conclusions, while the corresponding symbolic cases are nested
  1211 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1212 see src/HOL/Induct/Common_Patterns.thy, for example.
  1213 
  1214 * Method "induct": mutual induction rules are now specified as a list
  1215 of rule sharing the same induction cases. HOL packages usually provide
  1216 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1217 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1218 mutual induction rules differently, i.e. like this:
  1219 
  1220   (induct rule: foo_bar.inducts)
  1221   (induct set: foo bar)
  1222   (induct pred: foo bar)
  1223   (induct type: foo bar)
  1224 
  1225 The ML function ProjectRule.projections turns old-style rules into the
  1226 new format.
  1227 
  1228 * Method "coinduct": dual of induction, see
  1229 src/HOL/Library/Coinductive_List.thy for various examples.
  1230 
  1231 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1232 considered a legacy feature.
  1233 
  1234 * Attribute "symmetric" produces result with standardized schematic
  1235 variables (index 0).  Potential INCOMPATIBILITY.
  1236 
  1237 * Simplifier: by default the simplifier trace only shows top level
  1238 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1239 default. Thus there is less danger of being flooded by the trace. The
  1240 trace indicates where parts have been suppressed.
  1241   
  1242 * Provers/classical: removed obsolete classical version of elim_format
  1243 attribute; classical elim/dest rules are now treated uniformly when
  1244 manipulating the claset.
  1245 
  1246 * Provers/classical: stricter checks to ensure that supplied intro,
  1247 dest and elim rules are well-formed; dest and elim rules must have at
  1248 least one premise.
  1249 
  1250 * Provers/classical: attributes dest/elim/intro take an optional
  1251 weight argument for the rule (just as the Pure versions).  Weights are
  1252 ignored by automated tools, but determine the search order of single
  1253 rule steps.
  1254 
  1255 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1256 where the body does not mention the bound variable.  Note that dummy
  1257 patterns implicitly depend on their context of bounds, which makes
  1258 "{_. _}" match any set comprehension as expected.  Potential
  1259 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1260 constant "_idtdummy" in the binding position.
  1261 
  1262 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1263 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1264 for example "A -> B" => "Pi A (%_. B)".
  1265 
  1266 * Pure: 'class_deps' command visualizes the subclass relation, using
  1267 the graph browser tool.
  1268 
  1269 * Pure: 'print_theory' now suppresses certain internal declarations by
  1270 default; use '!' option for full details.
  1271 
  1272 
  1273 *** HOL ***
  1274 
  1275 * Method "metis" proves goals by applying the Metis general-purpose
  1276 resolution prover (see also http://gilith.com/software/metis/).
  1277 Examples are in the directory MetisExamples.  WARNING: the
  1278 Isabelle/HOL-Metis integration does not yet work properly with
  1279 multi-threading.
  1280   
  1281 * Command 'sledgehammer' invokes external automatic theorem provers as
  1282 background processes.  It generates calls to the "metis" method if
  1283 successful. These can be pasted into the proof.  Users do not have to
  1284 wait for the automatic provers to return.  WARNING: does not really
  1285 work with multi-threading.
  1286 
  1287 * New "auto_quickcheck" feature tests outermost goal statements for
  1288 potential counter-examples.  Controlled by ML references
  1289 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1290 5000 milliseconds).  Fails silently if statements is outside of
  1291 executable fragment, or any other codgenerator problem occurs.
  1292 
  1293 * New constant "undefined" with axiom "undefined x = undefined".
  1294 
  1295 * Added class "HOL.eq", allowing for code generation with polymorphic
  1296 equality.
  1297 
  1298 * Some renaming of class constants due to canonical name prefixing in
  1299 the new 'class' package:
  1300 
  1301     HOL.abs ~> HOL.abs_class.abs
  1302     HOL.divide ~> HOL.divide_class.divide
  1303     0 ~> HOL.zero_class.zero
  1304     1 ~> HOL.one_class.one
  1305     op + ~> HOL.plus_class.plus
  1306     op - ~> HOL.minus_class.minus
  1307     uminus ~> HOL.minus_class.uminus
  1308     op * ~> HOL.times_class.times
  1309     op < ~> HOL.ord_class.less
  1310     op <= > HOL.ord_class.less_eq
  1311     Nat.power ~> Power.power_class.power
  1312     Nat.size ~> Nat.size_class.size
  1313     Numeral.number_of ~> Numeral.number_class.number_of
  1314     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1315     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1316     Orderings.min ~> Orderings.ord_class.min
  1317     Orderings.max ~> Orderings.ord_class.max
  1318     Divides.op div ~> Divides.div_class.div
  1319     Divides.op mod ~> Divides.div_class.mod
  1320     Divides.op dvd ~> Divides.div_class.dvd
  1321 
  1322 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1323 
  1324 a) User-defined constants using any of the names "plus", "minus",
  1325 "times", "less" or "less_eq". The standard syntax translations for
  1326 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1327 names.
  1328 
  1329 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1330 INCOMPATIBILITY: use more specific names.
  1331 
  1332 c) Permutative equations (e.g. "a + b = b + a")
  1333 Since the change of names also changes the order of terms, permutative
  1334 rewrite rules may get applied in a different order. Experience shows
  1335 that this is rarely the case (only two adaptions in the whole Isabelle
  1336 distribution).  INCOMPATIBILITY: rewrite proofs
  1337 
  1338 d) ML code directly refering to constant names
  1339 This in general only affects hand-written proof tactics, simprocs and
  1340 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1341 Consider using @{const_name} antiquotation.
  1342 
  1343 * New class "default" with associated constant "default".
  1344 
  1345 * Function "sgn" is now overloaded and available on int, real, complex
  1346 (and other numeric types), using class "sgn".  Two possible defs of
  1347 sgn are given as equational assumptions in the classes sgn_if and
  1348 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1349 INCOMPATIBILITY.
  1350 
  1351 * Locale "partial_order" now unified with class "order" (cf. theory
  1352 Orderings), added parameter "less".  INCOMPATIBILITY.
  1353 
  1354 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1355 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1356 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1357 
  1358 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1359 changed order of proof goals in instance proofs.
  1360 
  1361 * The transitivity reasoner for partial and linear orders is set up
  1362 for classes "order" and "linorder".  Instances of the reasoner are available
  1363 in all contexts importing or interpreting the corresponding locales.
  1364 Method "order" invokes the reasoner separately; the reasoner
  1365 is also integrated with the Simplifier as a solver.  Diagnostic
  1366 command 'print_orders' shows the available instances of the reasoner
  1367 in the current context.
  1368 
  1369 * Localized monotonicity predicate in theory "Orderings"; integrated
  1370 lemmas max_of_mono and min_of_mono with this predicate.
  1371 INCOMPATIBILITY.
  1372 
  1373 * Formulation of theorem "dense" changed slightly due to integration
  1374 with new class dense_linear_order.
  1375 
  1376 * Uniform lattice theory development in HOL.
  1377 
  1378     constants "meet" and "join" now named "inf" and "sup"
  1379     constant "Meet" now named "Inf"
  1380 
  1381     classes "meet_semilorder" and "join_semilorder" now named
  1382       "lower_semilattice" and "upper_semilattice"
  1383     class "lorder" now named "lattice"
  1384     class "comp_lat" now named "complete_lattice"
  1385 
  1386     Instantiation of lattice classes allows explicit definitions
  1387     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1388 
  1389   INCOMPATIBILITY.  Theorem renames:
  1390 
  1391     meet_left_le            ~> inf_le1
  1392     meet_right_le           ~> inf_le2
  1393     join_left_le            ~> sup_ge1
  1394     join_right_le           ~> sup_ge2
  1395     meet_join_le            ~> inf_sup_ord
  1396     le_meetI                ~> le_infI
  1397     join_leI                ~> le_supI
  1398     le_meet                 ~> le_inf_iff
  1399     le_join                 ~> ge_sup_conv
  1400     meet_idempotent         ~> inf_idem
  1401     join_idempotent         ~> sup_idem
  1402     meet_comm               ~> inf_commute
  1403     join_comm               ~> sup_commute
  1404     meet_leI1               ~> le_infI1
  1405     meet_leI2               ~> le_infI2
  1406     le_joinI1               ~> le_supI1
  1407     le_joinI2               ~> le_supI2
  1408     meet_assoc              ~> inf_assoc
  1409     join_assoc              ~> sup_assoc
  1410     meet_left_comm          ~> inf_left_commute
  1411     meet_left_idempotent    ~> inf_left_idem
  1412     join_left_comm          ~> sup_left_commute
  1413     join_left_idempotent    ~> sup_left_idem
  1414     meet_aci                ~> inf_aci
  1415     join_aci                ~> sup_aci
  1416     le_def_meet             ~> le_iff_inf
  1417     le_def_join             ~> le_iff_sup
  1418     join_absorp2            ~> sup_absorb2
  1419     join_absorp1            ~> sup_absorb1
  1420     meet_absorp1            ~> inf_absorb1
  1421     meet_absorp2            ~> inf_absorb2
  1422     meet_join_absorp        ~> inf_sup_absorb
  1423     join_meet_absorp        ~> sup_inf_absorb
  1424     distrib_join_le         ~> distrib_sup_le
  1425     distrib_meet_le         ~> distrib_inf_le
  1426 
  1427     add_meet_distrib_left   ~> add_inf_distrib_left
  1428     add_join_distrib_left   ~> add_sup_distrib_left
  1429     is_join_neg_meet        ~> is_join_neg_inf
  1430     is_meet_neg_join        ~> is_meet_neg_sup
  1431     add_meet_distrib_right  ~> add_inf_distrib_right
  1432     add_join_distrib_right  ~> add_sup_distrib_right
  1433     add_meet_join_distribs  ~> add_sup_inf_distribs
  1434     join_eq_neg_meet        ~> sup_eq_neg_inf
  1435     meet_eq_neg_join        ~> inf_eq_neg_sup
  1436     add_eq_meet_join        ~> add_eq_inf_sup
  1437     meet_0_imp_0            ~> inf_0_imp_0
  1438     join_0_imp_0            ~> sup_0_imp_0
  1439     meet_0_eq_0             ~> inf_0_eq_0
  1440     join_0_eq_0             ~> sup_0_eq_0
  1441     neg_meet_eq_join        ~> neg_inf_eq_sup
  1442     neg_join_eq_meet        ~> neg_sup_eq_inf
  1443     join_eq_if              ~> sup_eq_if
  1444 
  1445     mono_meet               ~> mono_inf
  1446     mono_join               ~> mono_sup
  1447     meet_bool_eq            ~> inf_bool_eq
  1448     join_bool_eq            ~> sup_bool_eq
  1449     meet_fun_eq             ~> inf_fun_eq
  1450     join_fun_eq             ~> sup_fun_eq
  1451     meet_set_eq             ~> inf_set_eq
  1452     join_set_eq             ~> sup_set_eq
  1453     meet1_iff               ~> inf1_iff
  1454     meet2_iff               ~> inf2_iff
  1455     meet1I                  ~> inf1I
  1456     meet2I                  ~> inf2I
  1457     meet1D1                 ~> inf1D1
  1458     meet2D1                 ~> inf2D1
  1459     meet1D2                 ~> inf1D2
  1460     meet2D2                 ~> inf2D2
  1461     meet1E                  ~> inf1E
  1462     meet2E                  ~> inf2E
  1463     join1_iff               ~> sup1_iff
  1464     join2_iff               ~> sup2_iff
  1465     join1I1                 ~> sup1I1
  1466     join2I1                 ~> sup2I1
  1467     join1I1                 ~> sup1I1
  1468     join2I2                 ~> sup1I2
  1469     join1CI                 ~> sup1CI
  1470     join2CI                 ~> sup2CI
  1471     join1E                  ~> sup1E
  1472     join2E                  ~> sup2E
  1473 
  1474     is_meet_Meet            ~> is_meet_Inf
  1475     Meet_bool_def           ~> Inf_bool_def
  1476     Meet_fun_def            ~> Inf_fun_def
  1477     Meet_greatest           ~> Inf_greatest
  1478     Meet_lower              ~> Inf_lower
  1479     Meet_set_def            ~> Inf_set_def
  1480 
  1481     Sup_def                 ~> Sup_Inf
  1482     Sup_bool_eq             ~> Sup_bool_def
  1483     Sup_fun_eq              ~> Sup_fun_def
  1484     Sup_set_eq              ~> Sup_set_def
  1485 
  1486     listsp_meetI            ~> listsp_infI
  1487     listsp_meet_eq          ~> listsp_inf_eq
  1488 
  1489     meet_min                ~> inf_min
  1490     join_max                ~> sup_max
  1491 
  1492 * Added syntactic class "size"; overloaded constant "size" now has
  1493 type "'a::size ==> bool"
  1494 
  1495 * Internal reorganisation of `size' of datatypes: size theorems
  1496 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1497 simplification rules by default!); theorems "prod.size" now named
  1498 "*.size".
  1499 
  1500 * Class "div" now inherits from class "times" rather than "type".
  1501 INCOMPATIBILITY.
  1502 
  1503 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1504 Linorder etc.  have disappeared; operations defined in terms of
  1505 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1506 
  1507 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1508 
  1509 * HOL-Word: New extensive library and type for generic, fixed size
  1510 machine words, with arithemtic, bit-wise, shifting and rotating
  1511 operations, reflection into int, nat, and bool lists, automation for
  1512 linear arithmetic (by automatic reflection into nat or int), including
  1513 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1514 arithmetic type classes, supporting automatic simplification of
  1515 numerals on all operations.
  1516 
  1517 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1518 
  1519 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1520 
  1521 * Code generator library theories:
  1522   - Code_Integer represents HOL integers by big integer literals in target
  1523     languages.
  1524   - Code_Char represents HOL characters by character literals in target
  1525     languages.
  1526   - Code_Char_chr like Code_Char, but also offers treatment of character
  1527     codes; includes Code_Integer.
  1528   - Executable_Set allows to generate code for finite sets using lists.
  1529   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1530     denominator).
  1531   - Executable_Real implements a subset of real numbers, namly those
  1532     representable by rational numbers.
  1533   - Efficient_Nat implements natural numbers by integers, which in general will
  1534     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1535     includes Code_Integer.
  1536   - Code_Index provides an additional datatype index which is mapped to
  1537     target-language built-in integers.
  1538   - Code_Message provides an additional datatype message_string which is isomorphic to
  1539     strings; messages are mapped to target-language strings.
  1540 
  1541 * New package for inductive predicates
  1542 
  1543   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1544 
  1545     inductive
  1546       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1547       for z_1 :: U_1 and ... and z_n :: U_m
  1548     where
  1549       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1550     | ...
  1551 
  1552   with full support for type-inference, rather than
  1553 
  1554     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1555 
  1556     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1557     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1558 
  1559     inductive "s z_1 ... z_m"
  1560     intros
  1561       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1562       ...
  1563 
  1564   For backward compatibility, there is a wrapper allowing inductive
  1565   sets to be defined with the new package via
  1566 
  1567     inductive_set
  1568       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1569       for z_1 :: U_1 and ... and z_n :: U_m
  1570     where
  1571       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1572     | ...
  1573 
  1574   or
  1575 
  1576     inductive_set
  1577       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1578       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1579       for z_1 :: U_1 and ... and z_n :: U_m
  1580     where
  1581       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1582     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1583     | ...
  1584 
  1585   if the additional syntax "p ..." is required.
  1586 
  1587   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1588   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1589 
  1590   INCOMPATIBILITIES:
  1591 
  1592   - Since declaration and definition of inductive sets or predicates
  1593     is no longer separated, abbreviations involving the newly
  1594     introduced sets or predicates must be specified together with the
  1595     introduction rules after the 'where' keyword (see above), rather
  1596     than before the actual inductive definition.
  1597 
  1598   - The variables in induction and elimination rules are now
  1599     quantified in the order of their occurrence in the introduction
  1600     rules, rather than in alphabetical order. Since this may break
  1601     some proofs, these proofs either have to be repaired, e.g. by
  1602     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1603     statements of the form
  1604 
  1605       case (rule_i a_i_1 ... a_i_{k_i})
  1606 
  1607     or the old order of quantification has to be restored by explicitly adding
  1608     meta-level quantifiers in the introduction rules, i.e.
  1609 
  1610       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  1611 
  1612   - The format of the elimination rules is now
  1613 
  1614       p z_1 ... z_m x_1 ... x_n ==>
  1615         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1616         ==> ... ==> P
  1617 
  1618     for predicates and
  1619 
  1620       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1621         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1622         ==> ... ==> P
  1623 
  1624     for sets rather than
  1625 
  1626       x : s z_1 ... z_m ==>
  1627         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1628         ==> ... ==> P
  1629 
  1630     This may require terms in goals to be expanded to n-tuples
  1631     (e.g. using case_tac or simplification with the split_paired_all
  1632     rule) before the above elimination rule is applicable.
  1633 
  1634   - The elimination or case analysis rules for (mutually) inductive
  1635     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1636     list of rules "p_1_..._p_k.elims" is no longer available.
  1637 
  1638 * New package "function"/"fun" for general recursive functions,
  1639 supporting mutual and nested recursion, definitions in local contexts,
  1640 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1641 for small examples, and the separate tutorial on the function
  1642 package. The old recdef "package" is still available as before, but
  1643 users are encouraged to use the new package.
  1644 
  1645 * Method "lexicographic_order" automatically synthesizes termination
  1646 relations as lexicographic combinations of size measures. 
  1647 
  1648 * Case-expressions allow arbitrary constructor-patterns (including
  1649 "_") and take their order into account, like in functional
  1650 programming.  Internally, this is translated into nested
  1651 case-expressions; missing cases are added and mapped to the predefined
  1652 constant "undefined". In complicated cases printing may no longer show
  1653 the original input but the internal form. Lambda-abstractions allow
  1654 the same form of pattern matching: "% pat1 => e1 | ..." is an
  1655 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  1656 variable.
  1657 
  1658 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  1659 is an abbreviation for "of_nat :: nat => int". The simplification
  1660 rules for "of_nat" have been changed to work like "int" did
  1661 previously.  Potential INCOMPATIBILITY:
  1662   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  1663   - of_nat_diff and of_nat_mult are no longer default simp rules
  1664 
  1665 * Method "algebra" solves polynomial equations over (semi)rings using
  1666 Groebner bases. The (semi)ring structure is defined by locales and the
  1667 tool setup depends on that generic context. Installing the method for
  1668 a specific type involves instantiating the locale and possibly adding
  1669 declarations for computation on the coefficients.  The method is
  1670 already instantiated for natural numbers and for the axiomatic class
  1671 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  1672 CALCULEMUS 2007 for the general principles underlying this
  1673 architecture of context-aware proof-tools.
  1674 
  1675 * Method "ferrack" implements quantifier elimination over
  1676 special-purpose dense linear orders using locales (analogous to
  1677 "algebra"). The method is already installed for class
  1678 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  1679 rat, etc.
  1680 
  1681 * Former constant "List.op @" now named "List.append".  Use ML
  1682 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  1683 circumvent possible incompatibilities when working on ML level.
  1684 
  1685 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1686 
  1687 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1688 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1689 
  1690 * New syntax for Haskell-like list comprehension (input only), eg.
  1691 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1692 
  1693 * The special syntax for function "filter" has changed from [x :
  1694 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1695 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1696 
  1697 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1698 defined on nat only, as an abbreviation for [a..<Suc b]
  1699 INCOMPATIBILITY.
  1700 
  1701 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1702 
  1703 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1704 
  1705 * New lemma collection field_simps (an extension of ring_simps) for
  1706 manipulating (in)equations involving division. Multiplies with all
  1707 denominators that can be proved to be non-zero (in equations) or
  1708 positive/negative (in inequations).
  1709 
  1710 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1711 have been improved and renamed to ring_simps, group_simps and
  1712 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1713 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1714 
  1715 * Theory Library/Commutative_Ring: switched from recdef to function
  1716 package; constants add, mul, pow now curried.  Infix syntax for
  1717 algebraic operations.
  1718 
  1719 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1720 INCOMPATIBILITY.
  1721 
  1722 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1723 INCOMPATIBILITY.
  1724 
  1725 * HOL/records: generalised field-update to take a function on the
  1726 field rather than the new value: r(|A := x|) is translated to A_update
  1727 (K x) r The K-combinator that is internally used is called K_record.
  1728 INCOMPATIBILITY: Usage of the plain update functions has to be
  1729 adapted.
  1730  
  1731 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1732 * x = 0, which are required for a semiring.  Richer structures do not
  1733 inherit from semiring_0 anymore, because this property is a theorem
  1734 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1735 there is more to prove, but this is mostly trivial.
  1736 
  1737 * Class "recpower" is generalized to arbitrary monoids, not just
  1738 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1739 commutativity or semiring properties additionally.
  1740 
  1741 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1742 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1743 better use 'abbreviation'.
  1744 
  1745 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1746 
  1747 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1748 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1749 significant changes for setting up numeral syntax for types:
  1750   - New constants Numeral.pred and Numeral.succ instead
  1751       of former Numeral.bin_pred and Numeral.bin_succ.
  1752   - Use integer operations instead of bin_add, bin_mult and so on.
  1753   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1754   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1755 
  1756 See src/HOL/Integ/IntArith.thy for an example setup.
  1757 
  1758 * Command 'normal_form' computes the normal form of a term that may
  1759 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1760 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1761 heavy-duty computations because the functions are compiled to ML
  1762 first.  Correspondingly, a method "normalization" is provided.  See
  1763 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1764 
  1765 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1766 25 like -->); output depends on the "iff" print_mode, the default is
  1767 "A = B" (with priority 50).
  1768 
  1769 * Relations less (<) and less_eq (<=) are also available on type bool.
  1770 Modified syntax to disallow nesting without explicit parentheses,
  1771 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1772 INCOMPATIBILITY.
  1773 
  1774 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1775 
  1776 * Relation composition operator "op O" now has precedence 75 and binds
  1777 stronger than union and intersection. INCOMPATIBILITY.
  1778 
  1779 * The old set interval syntax "{m..n(}" (and relatives) has been
  1780 removed.  Use "{m..<n}" (and relatives) instead.
  1781 
  1782 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1783 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1784 ``declare [[simproc del: neq]]''.
  1785 
  1786 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1787 True/False.
  1788 
  1789 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1790 
  1791 * Theorem setsum_mult renamed to setsum_right_distrib.
  1792 
  1793 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1794 ``rule'' method.
  1795 
  1796 * Reimplemented methods "sat" and "satx", with several improvements:
  1797 goals no longer need to be stated as "<prems> ==> False", equivalences
  1798 (i.e. "=" on type bool) are handled, variable names of the form
  1799 "lit_<n>" are no longer reserved, significant speedup.
  1800 
  1801 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1802 zChaff is still supported as well.
  1803 
  1804 * 'inductive' and 'datatype': provide projections of mutual rules,
  1805 bundled as foo_bar.inducts;
  1806 
  1807 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1808 Library.
  1809 
  1810 * Library: moved theory Accessible_Part to main HOL.
  1811 
  1812 * Library: added theory Coinductive_List of potentially infinite lists
  1813 as greatest fixed-point.
  1814 
  1815 * Library: added theory AssocList which implements (finite) maps as
  1816 association lists.
  1817 
  1818 * Method "evaluation" solves goals (i.e. a boolean expression)
  1819 efficiently by compiling it to ML.  The goal is "proved" (via an
  1820 oracle) if it evaluates to True.
  1821 
  1822 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1823 also when invoked by the simplifier.  This results in the Simplifier
  1824 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1825 Configuration option fast_arith_split_limit=0 recovers the old
  1826 behavior.
  1827 
  1828 * Support for hex (0x20) and binary (0b1001) numerals.
  1829 
  1830 * New method: reify eqs (t), where eqs are equations for an
  1831 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1832 parameter, computes a term s::'b and a list xs::'a list and proves the
  1833 theorem I xs s = t. This is also known as reification or quoting. The
  1834 resulting theorem is applied to the subgoal to substitute t with I xs
  1835 s.  If t is omitted, the subgoal itself is reified.
  1836 
  1837 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1838 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1839 where f is supposed to be a computable function (in the sense of code
  1840 generattion). The method uses reify to compute s and xs as above then
  1841 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1842 r and finally gets the theorem t = r, which is again applied to the
  1843 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1844 
  1845 * Reflection: Automatic reification now handels binding, an example is
  1846 available in src/HOL/ex/ReflectionEx.thy
  1847 
  1848 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  1849 command 'statespace' that is similar to 'record', but introduces an
  1850 abstract specification based on the locale infrastructure instead of
  1851 HOL types.  This leads to extra flexibility in composing state spaces,
  1852 in particular multiple inheritance and renaming of components.
  1853 
  1854 
  1855 *** HOL-Complex ***
  1856 
  1857 * Hyperreal: Functions root and sqrt are now defined on negative real
  1858 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1859 Nonnegativity side conditions have been removed from many lemmas, so
  1860 that more subgoals may now be solved by simplification; potential
  1861 INCOMPATIBILITY.
  1862 
  1863 * Real: new type classes formalize real normed vector spaces and
  1864 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1865 and norm :: 'a => real.
  1866 
  1867 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1868 reals into other types. The overloaded constant Reals :: 'a set is now
  1869 defined as range of_real; potential INCOMPATIBILITY.
  1870 
  1871 * Real: proper support for ML code generation, including 'quickcheck'.
  1872 Reals are implemented as arbitrary precision rationals.
  1873 
  1874 * Hyperreal: Several constants that previously worked only for the
  1875 reals have been generalized, so they now work over arbitrary vector
  1876 spaces. Type annotations may need to be added in some cases; potential
  1877 INCOMPATIBILITY.
  1878 
  1879   Infinitesimal  :: ('a::real_normed_vector) star set
  1880   HFinite        :: ('a::real_normed_vector) star set
  1881   HInfinite      :: ('a::real_normed_vector) star set
  1882   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1883   monad          :: ('a::real_normed_vector) star => 'a star set
  1884   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1885   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1886   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1887   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1888   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1889   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1890   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1891   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1892   sgn            :: 'a::real_normed_vector => 'a
  1893   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1894 
  1895 * Complex: Some complex-specific constants are now abbreviations for
  1896 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1897 hnorm.  Other constants have been entirely removed in favor of the
  1898 polymorphic versions (INCOMPATIBILITY):
  1899 
  1900   approx        <-- capprox
  1901   HFinite       <-- CFinite
  1902   HInfinite     <-- CInfinite
  1903   Infinitesimal <-- CInfinitesimal
  1904   monad         <-- cmonad
  1905   galaxy        <-- cgalaxy
  1906   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1907   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1908   (ns)deriv     <-- (ns)cderiv
  1909 
  1910 
  1911 *** HOL-Algebra ***
  1912 
  1913 * Formalisation of ideals and the quotient construction over rings.
  1914 
  1915 * Order and lattice theory no longer based on records.
  1916 INCOMPATIBILITY.
  1917 
  1918 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1919 greatest_closed.  INCOMPATIBILITY.
  1920 
  1921 * Method algebra is now set up via an attribute.  For examples see
  1922 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1923 of algebraic structures.
  1924 
  1925 * Renamed theory CRing to Ring.
  1926 
  1927 
  1928 *** HOL-Nominal ***
  1929 
  1930 * Substantial, yet incomplete support for nominal datatypes (binding
  1931 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  1932 src/HOL/Nominal/Examples.  Prospective users should consult
  1933 http://isabelle.in.tum.de/nominal/
  1934 
  1935 
  1936 *** ML ***
  1937 
  1938 * ML basics: just one true type int, which coincides with IntInf.int
  1939 (even on SML/NJ).
  1940 
  1941 * ML within Isar: antiquotations allow to embed statically-checked
  1942 formal entities in the source, referring to the context available at
  1943 compile-time.  For example:
  1944 
  1945 ML {* @{sort "{zero,one}"} *}
  1946 ML {* @{typ "'a => 'b"} *}
  1947 ML {* @{term "%x. x"} *}
  1948 ML {* @{prop "x == y"} *}
  1949 ML {* @{ctyp "'a => 'b"} *}
  1950 ML {* @{cterm "%x. x"} *}
  1951 ML {* @{cprop "x == y"} *}
  1952 ML {* @{thm asm_rl} *}
  1953 ML {* @{thms asm_rl} *}
  1954 ML {* @{type_name c} *}
  1955 ML {* @{type_syntax c} *}
  1956 ML {* @{const_name c} *}
  1957 ML {* @{const_syntax c} *}
  1958 ML {* @{context} *}
  1959 ML {* @{theory} *}
  1960 ML {* @{theory Pure} *}
  1961 ML {* @{theory_ref} *}
  1962 ML {* @{theory_ref Pure} *}
  1963 ML {* @{simpset} *}
  1964 ML {* @{claset} *}
  1965 ML {* @{clasimpset} *}
  1966 
  1967 The same works for sources being ``used'' within an Isar context.
  1968 
  1969 * ML in Isar: improved error reporting; extra verbosity with
  1970 ML_Context.trace enabled.
  1971 
  1972 * Pure/General/table.ML: the join operations now works via exceptions
  1973 DUP/SAME instead of type option. This is simpler in simple cases, and
  1974 admits slightly more efficient complex applications.
  1975 
  1976 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1977 use Context.generic instead of just theory.
  1978 
  1979 * Pure: datatype Context.generic joins theory/Proof.context and
  1980 provides some facilities for code that works in either kind of
  1981 context, notably GenericDataFun for uniform theory and proof data.
  1982 
  1983 * Pure: simplified internal attribute type, which is now always
  1984 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  1985 local (Proof.context) attributes have been discontinued, while
  1986 minimizing code duplication. Thm.rule_attribute and
  1987 Thm.declaration_attribute build canonical attributes; see also structure
  1988 Context for further operations on Context.generic, notably
  1989 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  1990 declarations and definitions.
  1991 
  1992 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1993 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1994 init only required for impure data. INCOMPATIBILITY: empty really need
  1995 to be empty (no dependencies on theory content!)
  1996 
  1997 * Pure/kernel: consts certification ignores sort constraints given in
  1998 signature declarations. (This information is not relevant to the
  1999 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2000 potential INCOMPATIBILITY.
  2001 
  2002 * Pure: axiomatic type classes are now purely definitional, with
  2003 explicit proofs of class axioms and super class relations performed
  2004 internally. See Pure/axclass.ML for the main internal interfaces --
  2005 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2006 AxClass.axiomatize_class/classrel/arity supersede
  2007 Sign.add_classes/classrel/arities.
  2008 
  2009 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2010 global/local versions on theory vs. Proof.context have been
  2011 discontinued; Attrib.syntax and Method.syntax have been adapted
  2012 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2013 attributes, methods, etc.
  2014 
  2015 * Pure: several functions of signature "... -> theory -> theory * ..."
  2016 have been reoriented to "... -> theory -> ... * theory" in order to
  2017 allow natural usage in combination with the ||>, ||>>, |-> and
  2018 fold_map combinators.
  2019 
  2020 * Pure: official theorem names (closed derivations) and additional
  2021 comments (tags) are now strictly separate.  Name hints -- which are
  2022 maintained as tags -- may be attached any time without affecting the
  2023 derivation.
  2024 
  2025 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2026 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2027 achieve the old behaviour.
  2028 
  2029 * Pure: the "Goal" constant is now called "prop", supporting a
  2030 slightly more general idea of ``protecting'' meta-level rule
  2031 statements.
  2032 
  2033 * Pure: Logic.(un)varify only works in a global context, which is now
  2034 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2035 Logic.legacy_(un)varify as temporary workaround.
  2036 
  2037 * Pure: structure Name provides scalable operations for generating
  2038 internal variable names, notably Name.variants etc.  This replaces
  2039 some popular functions from term.ML:
  2040 
  2041   Term.variant		->  Name.variant
  2042   Term.variantlist	->  Name.variant_list
  2043   Term.invent_names	->  Name.invent_list
  2044 
  2045 Note that low-level renaming rarely occurs in new code -- operations
  2046 from structure Variable are used instead (see below).
  2047 
  2048 * Pure: structure Variable provides fundamental operations for proper
  2049 treatment of fixed/schematic variables in a context.  For example,
  2050 Variable.import introduces fixes for schematics of given facts and
  2051 Variable.export reverses the effect (up to renaming) -- this replaces
  2052 various freeze_thaw operations.
  2053 
  2054 * Pure: structure Goal provides simple interfaces for
  2055 init/conclude/finish and tactical prove operations (replacing former
  2056 Tactic.prove).  Goal.prove is the canonical way to prove results
  2057 within a given context; Goal.prove_global is a degraded version for
  2058 theory level goals, including a global Drule.standard.  Note that
  2059 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2060 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2061 in a locale context).
  2062 
  2063 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2064 and type checking (Syntax.check_term etc.), with common combinations
  2065 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2066 which are considered legacy and await removal.
  2067 
  2068 * Pure/Syntax: generic interfaces for type unchecking
  2069 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2070 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2071 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2072 available for convenience, but refer to the very same operations using
  2073 a mere theory instead of a full context.
  2074 
  2075 * Isar: simplified treatment of user-level errors, using exception
  2076 ERROR of string uniformly.  Function error now merely raises ERROR,
  2077 without any side effect on output channels.  The Isar toplevel takes
  2078 care of proper display of ERROR exceptions.  ML code may use plain
  2079 handle/can/try; cat_error may be used to concatenate errors like this:
  2080 
  2081   ... handle ERROR msg => cat_error msg "..."
  2082 
  2083 Toplevel ML code (run directly or through the Isar toplevel) may be
  2084 embedded into the Isar toplevel with exception display/debug like
  2085 this:
  2086 
  2087   Isar.toplevel (fn () => ...)
  2088 
  2089 INCOMPATIBILITY, removed special transform_error facilities, removed
  2090 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2091 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2092 -- use plain ERROR instead.
  2093 
  2094 * Isar: theory setup now has type (theory -> theory), instead of a
  2095 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2096 
  2097 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2098 ProofContext.debug/verbose flags.
  2099 
  2100 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2101 theory before entering a proof state.  Transactions now always see a
  2102 quasi-functional intermediate checkpoint, both in interactive and
  2103 batch mode.
  2104 
  2105 * Isar: simplified interfaces for outer syntax.  Renamed
  2106 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2107 OuterSyntax.add_parsers -- this functionality is now included in
  2108 OuterSyntax.command etc.  INCOMPATIBILITY.
  2109 
  2110 * Simplifier: the simpset of a running simplification process now
  2111 contains a proof context (cf. Simplifier.the_context), which is the
  2112 very context that the initial simpset has been retrieved from (by
  2113 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2114 (solver, looper etc.) may depend on arbitrary proof data.
  2115 
  2116 * Simplifier.inherit_context inherits the proof context (plus the
  2117 local bounds) of the current simplification process; any simproc
  2118 etc. that calls the Simplifier recursively should do this!  Removed
  2119 former Simplifier.inherit_bounds, which is already included here --
  2120 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2121 specify an explicit context using Simplifier.context/theory_context.
  2122 
  2123 * Simplifier/Classical Reasoner: more abstract interfaces
  2124 change_simpset/claset for modifying the simpset/claset reference of a
  2125 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2126 INCOMPATIBILITY.
  2127 
  2128 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2129 "Trueprop" etc.
  2130 
  2131 
  2132 *** System ***
  2133 
  2134 * settings: the default heap location within ISABELLE_HOME_USER now
  2135 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2136 Isabelle installations.
  2137 
  2138 * isabelle-process: option -S (secure mode) disables some critical
  2139 operations, notably runtime compilation and evaluation of ML source
  2140 code.
  2141 
  2142 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2143 
  2144 * Support for parallel execution, using native multicore support of
  2145 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2146 independent theories, according to the given theory header
  2147 specifications. The maximum number of worker threads is specified via
  2148 usedir option -M or the "max-threads" setting in Proof General. A
  2149 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2150 to 6 on a 8-core machine.  User-code needs to observe certain
  2151 guidelines for thread-safe programming, see appendix A in the Isar
  2152 Implementation manual.
  2153 
  2154 
  2155 
  2156 New in Isabelle2005 (October 2005)
  2157 ----------------------------------
  2158 
  2159 *** General ***
  2160 
  2161 * Theory headers: the new header syntax for Isar theories is
  2162 
  2163   theory <name>
  2164   imports <theory1> ... <theoryN>
  2165   uses <file1> ... <fileM>
  2166   begin
  2167 
  2168 where the 'uses' part is optional.  The previous syntax
  2169 
  2170   theory <name> = <theory1> + ... + <theoryN>:
  2171 
  2172 will disappear in the next release.  Use isatool fixheaders to convert
  2173 existing theory files.  Note that there is no change in ancient
  2174 non-Isar theories now, but these will disappear soon.
  2175 
  2176 * Theory loader: parent theories can now also be referred to via
  2177 relative and absolute paths.
  2178 
  2179 * Command 'find_theorems' searches for a list of criteria instead of a
  2180 list of constants. Known criteria are: intro, elim, dest, name:string,
  2181 simp:term, and any term. Criteria can be preceded by '-' to select
  2182 theorems that do not match. Intro, elim, dest select theorems that
  2183 match the current goal, name:s selects theorems whose fully qualified
  2184 name contain s, and simp:term selects all simplification rules whose
  2185 lhs match term.  Any other term is interpreted as pattern and selects
  2186 all theorems matching the pattern. Available in ProofGeneral under
  2187 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2188 
  2189   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2190 
  2191 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2192 matching the current goal as introduction rule and not having "HOL."
  2193 in their name (i.e. not being defined in theory HOL).
  2194 
  2195 * Command 'thms_containing' has been discontinued in favour of
  2196 'find_theorems'; INCOMPATIBILITY.
  2197 
  2198 * Communication with Proof General is now 8bit clean, which means that
  2199 Unicode text in UTF-8 encoding may be used within theory texts (both
  2200 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2201 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2202 
  2203   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2204   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2205 
  2206 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2207 Classical Reasoner.  Typical big applications run around 2 times
  2208 faster.
  2209 
  2210 
  2211 *** Document preparation ***
  2212 
  2213 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2214 of raw sources.  Only those symbols that do not require additional
  2215 LaTeX packages (depending on comments in isabellesym.sty) are
  2216 displayed properly, everything else is left verbatim.  isatool display
  2217 and isatool print are used as front ends (these are subject to the
  2218 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2219 
  2220 * Command tags control specific markup of certain regions of text,
  2221 notably folding and hiding.  Predefined tags include "theory" (for
  2222 theory begin and end), "proof" for proof commands, and "ML" for
  2223 commands involving ML code; the additional tags "visible" and
  2224 "invisible" are unused by default.  Users may give explicit tag
  2225 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2226 interpretation of tags is determined by the LaTeX job during document
  2227 preparation: see option -V of isatool usedir, or options -n and -t of
  2228 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2229 \isadroptag.
  2230 
  2231 Several document versions may be produced at the same time via isatool
  2232 usedir (the generated index.html will link all of them).  Typical
  2233 specifications include ''-V document=theory,proof,ML'' to present
  2234 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2235 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2236 these parts without any formal replacement text.  The Isabelle site
  2237 default settings produce ''document'' and ''outline'' versions as
  2238 specified above.
  2239 
  2240 * Several new antiquotations:
  2241 
  2242   @{term_type term} prints a term with its type annotated;
  2243 
  2244   @{typeof term} prints the type of a term;
  2245 
  2246   @{const const} is the same as @{term const}, but checks that the
  2247   argument is a known logical constant;
  2248 
  2249   @{term_style style term} and @{thm_style style thm} print a term or
  2250   theorem applying a "style" to it
  2251 
  2252   @{ML text}
  2253 
  2254 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2255 definitions, equations, inequations etc., 'concl' printing only the
  2256 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2257 to print the specified premise.  TermStyle.add_style provides an ML
  2258 interface for introducing further styles.  See also the "LaTeX Sugar"
  2259 document practical applications.  The ML antiquotation prints
  2260 type-checked ML expressions verbatim.
  2261 
  2262 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2263 and 'text' support optional locale specification '(in loc)', which
  2264 specifies the default context for interpreting antiquotations.  For
  2265 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2266 
  2267 * Option 'locale=NAME' of antiquotations specifies an alternative
  2268 context interpreting the subsequent argument.  For example: @{thm
  2269 [locale=lattice] inf_assoc}.
  2270 
  2271 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2272 a proof context.
  2273 
  2274 * Proper output of antiquotations for theory commands involving a
  2275 proof context (such as 'locale' or 'theorem (in loc) ...').
  2276 
  2277 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2278 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2279 
  2280 * isatool usedir: new option -C (default true) controls whether option
  2281 -D should include a copy of the original document directory; -C false
  2282 prevents unwanted effects such as copying of administrative CVS data.
  2283 
  2284 
  2285 *** Pure ***
  2286 
  2287 * Considerably improved version of 'constdefs' command.  Now performs
  2288 automatic type-inference of declared constants; additional support for
  2289 local structure declarations (cf. locales and HOL records), see also
  2290 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2291 sequential dependencies of definitions within a single 'constdefs'
  2292 section; moreover, the declared name needs to be an identifier.  If
  2293 all fails, consider to fall back on 'consts' and 'defs' separately.
  2294 
  2295 * Improved indexed syntax and implicit structures.  First of all,
  2296 indexed syntax provides a notational device for subscripted
  2297 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2298 expressions.  Secondly, in a local context with structure
  2299 declarations, number indexes \<^sub>n or the empty index (default
  2300 number 1) refer to a certain fixed variable implicitly; option
  2301 show_structs controls printing of implicit structures.  Typical
  2302 applications of these concepts involve record types and locales.
  2303 
  2304 * New command 'no_syntax' removes grammar declarations (and
  2305 translations) resulting from the given syntax specification, which is
  2306 interpreted in the same manner as for the 'syntax' command.
  2307 
  2308 * 'Advanced' translation functions (parse_translation etc.) may depend
  2309 on the signature of the theory context being presently used for
  2310 parsing/printing, see also isar-ref manual.
  2311 
  2312 * Improved 'oracle' command provides a type-safe interface to turn an
  2313 ML expression of type theory -> T -> term into a primitive rule of
  2314 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2315 is already included here); see also FOL/ex/IffExample.thy;
  2316 INCOMPATIBILITY.
  2317 
  2318 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2319 before); "cI" is no longer bound, use "c.intro" instead.
  2320 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2321 axclasses vs. locales.
  2322 
  2323 * Improved internal renaming of symbolic identifiers -- attach primes
  2324 instead of base 26 numbers.
  2325 
  2326 * New flag show_question_marks controls printing of leading question
  2327 marks in schematic variable names.
  2328 
  2329 * In schematic variable names, *any* symbol following \<^isub> or
  2330 \<^isup> is now treated as part of the base name.  For example, the
  2331 following works without printing of awkward ".0" indexes:
  2332 
  2333   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2334     by simp
  2335 
  2336 * Inner syntax includes (*(*nested*) comments*).
  2337 
  2338 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2339 annotations as "(00...)".
  2340 
  2341 * Clear separation of logical types and nonterminals, where the latter
  2342 may only occur in 'syntax' specifications or type abbreviations.
  2343 Before that distinction was only partially implemented via type class
  2344 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2345 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2346 exotic syntax specifications may require further adaption
  2347 (e.g. Cube/Cube.thy).
  2348 
  2349 * Removed obsolete type class "logic", use the top sort {} instead.
  2350 Note that non-logical types should be declared as 'nonterminals'
  2351 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2352 specifications.
  2353 
  2354 * Attributes 'induct' and 'cases': type or set names may now be
  2355 locally fixed variables as well.
  2356 
  2357 * Simplifier: can now control the depth to which conditional rewriting
  2358 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2359 Limit.
  2360 
  2361 * Simplifier: simplification procedures may now take the current
  2362 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2363 interface), which is very useful for calling the Simplifier
  2364 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2365 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2366 low-level mk_simproc no longer applies Logic.varify internally, to
  2367 allow for use in a context of fixed variables.
  2368 
  2369 * thin_tac now works even if the assumption being deleted contains !!
  2370 or ==>.  More generally, erule now works even if the major premise of
  2371 the elimination rule contains !! or ==>.
  2372 
  2373 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2374 
  2375 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2376 from Pure, which contains all common declarations already.  Both
  2377 theories are defined via plain Isabelle/Isar .thy files.
  2378 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2379 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2380 use isatool fixcpure to adapt your theory and ML sources.
  2381 
  2382 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2383 selections of theorems in named facts via index ranges.
  2384 
  2385 * 'print_theorems': in theory mode, really print the difference
  2386 wrt. the last state (works for interactive theory development only),
  2387 in proof mode print all local facts (cf. 'print_facts');
  2388 
  2389 * 'hide': option '(open)' hides only base names.
  2390 
  2391 * More efficient treatment of intermediate checkpoints in interactive
  2392 theory development.
  2393 
  2394 * Code generator is now invoked via code_module (incremental code
  2395 generation) and code_library (modular code generation, ML structures
  2396 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2397 must be quoted when used as identifiers.
  2398 
  2399 * New 'value' command for reading, evaluating and printing terms using
  2400 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2401 quoted when used as identifier.
  2402 
  2403 
  2404 *** Locales ***
  2405 
  2406 * New commands for the interpretation of locale expressions in
  2407 theories (1), locales (2) and proof contexts (3).  These generate
  2408 proof obligations from the expression specification.  After the
  2409 obligations have been discharged, theorems of the expression are added
  2410 to the theory, target locale or proof context.  The synopsis of the
  2411 commands is a follows:
  2412 
  2413   (1) interpretation expr inst
  2414   (2) interpretation target < expr
  2415   (3) interpret expr inst
  2416 
  2417 Interpretation in theories and proof contexts require a parameter
  2418 instantiation of terms from the current context.  This is applied to
  2419 specifications and theorems of the interpreted expression.
  2420 Interpretation in locales only permits parameter renaming through the
  2421 locale expression.  Interpretation is smart in that interpretations
  2422 that are active already do not occur in proof obligations, neither are
  2423 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2424 inspect active interpretations of a particular locale.  For details,
  2425 see the Isar Reference manual.  Examples can be found in
  2426 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2427 
  2428 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2429 'interpret' instead.
  2430 
  2431 * New context element 'constrains' for adding type constraints to
  2432 parameters.
  2433 
  2434 * Context expressions: renaming of parameters with syntax
  2435 redeclaration.
  2436 
  2437 * Locale declaration: 'includes' disallowed.
  2438 
  2439 * Proper static binding of attribute syntax -- i.e. types / terms /
  2440 facts mentioned as arguments are always those of the locale definition
  2441 context, independently of the context of later invocations.  Moreover,
  2442 locale operations (renaming and type / term instantiation) are applied
  2443 to attribute arguments as expected.
  2444 
  2445 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2446 actual attributes; rare situations may require Attrib.attribute to
  2447 embed those attributes into Attrib.src that lack concrete syntax.
  2448 Attribute implementations need to cooperate properly with the static
  2449 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2450 Attrib.XXX_thm etc. already do the right thing without further
  2451 intervention.  Only unusual applications -- such as "where" or "of"
  2452 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2453 on the context and the facts involved -- may have to assign parsed
  2454 values to argument tokens explicitly.
  2455 
  2456 * Changed parameter management in theorem generation for long goal
  2457 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2458 theorem statement in rare situations.
  2459 
  2460 * Locale inspection command 'print_locale' omits notes elements.  Use
  2461 'print_locale!' to have them included in the output.
  2462 
  2463 
  2464 *** Provers ***
  2465 
  2466 * Provers/hypsubst.ML: improved version of the subst method, for
  2467 single-step rewriting: it now works in bound variable contexts. New is
  2468 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2469 rewrite a different subterm than the original subst method, which is
  2470 still available as 'simplesubst'.
  2471 
  2472 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2473 and quasi orders.
  2474 
  2475 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2476 reflexive-transitive closure of relations.
  2477 
  2478 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2479 limit (previously hard-coded with a value of 20) user-definable.
  2480 
  2481 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2482 is peformed already.  Object-logics merely need to finish their
  2483 initial simpset configuration as before.  INCOMPATIBILITY.
  2484 
  2485 
  2486 *** HOL ***
  2487 
  2488 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2489 
  2490   syntax (epsilon)
  2491     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2492 
  2493 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2494 and x-symbol; use option '-m epsilon' to get it actually printed.
  2495 Moreover, the mathematically important symbolic identifier \<epsilon>
  2496 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2497 
  2498 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2499 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2500 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2501 support corresponding Isar calculations.
  2502 
  2503 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2504 instead of ":".
  2505 
  2506 * theory SetInterval: changed the syntax for open intervals:
  2507 
  2508   Old       New
  2509   {..n(}    {..<n}
  2510   {)n..}    {n<..}
  2511   {m..n(}   {m..<n}
  2512   {)m..n}   {m<..n}
  2513   {)m..n(}  {m<..<n}
  2514 
  2515 The old syntax is still supported but will disappear in the next
  2516 release.  For conversion use the following Emacs search and replace
  2517 patterns (these are not perfect but work quite well):
  2518 
  2519   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2520   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2521 
  2522 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2523 equalities in commutative rings; method 'algebra' provides a generic
  2524 interface.
  2525 
  2526 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2527 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2528 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2529 be a tuple pattern.
  2530 
  2531 Some new syntax forms are available:
  2532 
  2533   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2534   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2535   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2536   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2537 
  2538 The latter form "\<Sum>x < k. e" used to be based on a separate
  2539 function "Summation", which has been discontinued.
  2540 
  2541 * theory Finite_Set: in structured induction proofs, the insert case
  2542 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2543 (insert F x)'.
  2544 
  2545 * The 'refute' command has been extended to support a much larger
  2546 fragment of HOL, including axiomatic type classes, constdefs and
  2547 typedefs, inductive datatypes and recursion.
  2548 
  2549 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2550 Requires zChaff with proof generation to be installed.  See
  2551 HOL/ex/SAT_Examples.thy for examples.
  2552 
  2553 * Datatype induction via method 'induct' now preserves the name of the
  2554 induction variable. For example, when proving P(xs::'a list) by
  2555 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2556 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2557 in unstructured proof scripts.
  2558 
  2559 * Reworked implementation of records.  Improved scalability for
  2560 records with many fields, avoiding performance problems for type
  2561 inference. Records are no longer composed of nested field types, but
  2562 of nested extension types. Therefore the record type only grows linear
  2563 in the number of extensions and not in the number of fields.  The
  2564 top-level (users) view on records is preserved.  Potential
  2565 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2566 old record representation. The type generated for a record is called
  2567 <record_name>_ext_type.
  2568 
  2569 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2570 proofs triggered by a record definition or a simproc (if
  2571 quick_and_dirty is enabled).  Definitions of large records can take
  2572 quite long.
  2573 
  2574 New simproc record_upd_simproc for simplification of multiple record
  2575 updates enabled by default.  Moreover, trivial updates are also
  2576 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2577 occasionally, since simplification is more powerful by default.
  2578 
  2579 * typedef: proper support for polymorphic sets, which contain extra
  2580 type-variables in the term.
  2581 
  2582 * Simplifier: automatically reasons about transitivity chains
  2583 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2584 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2585 old proofs break occasionally as simplification may now solve more
  2586 goals than previously.
  2587 
  2588 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2589 present.  Works for all partial orders (class "order"), in particular
  2590 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2591 just like y <= x.
  2592 
  2593 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2594 bound variable or a constant then the let is unfolded.  Otherwise
  2595 first a is simplified to b, and then f b is simplified to g. If
  2596 possible we abstract b from g arriving at "let x = b in h x",
  2597 otherwise we unfold the let and arrive at g.  The simproc can be
  2598 enabled/disabled by the reference use_let_simproc.  Potential
  2599 INCOMPATIBILITY since simplification is more powerful by default.
  2600 
  2601 * Classical reasoning: the meson method now accepts theorems as arguments.
  2602 
  2603 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2604 jobs to provide advice on the provability of subgoals.
  2605 
  2606 * Theory OrderedGroup and Ring_and_Field: various additions and
  2607 improvements to faciliate calculations involving equalities and
  2608 inequalities.
  2609 
  2610 The following theorems have been eliminated or modified
  2611 (INCOMPATIBILITY):
  2612 
  2613   abs_eq             now named abs_of_nonneg
  2614   abs_of_ge_0        now named abs_of_nonneg
  2615   abs_minus_eq       now named abs_of_nonpos
  2616   imp_abs_id         now named abs_of_nonneg
  2617   imp_abs_neg_id     now named abs_of_nonpos
  2618   mult_pos           now named mult_pos_pos
  2619   mult_pos_le        now named mult_nonneg_nonneg
  2620   mult_pos_neg_le    now named mult_nonneg_nonpos
  2621   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2622   mult_neg           now named mult_neg_neg
  2623   mult_neg_le        now named mult_nonpos_nonpos
  2624 
  2625 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2626      
  2627      zero_le_square
  2628      not_square_less_zero 
  2629 
  2630   The following lemmas have been deleted from Real/RealPow:
  2631   
  2632      realpow_zero_zero
  2633      realpow_two
  2634      realpow_less
  2635      zero_le_power
  2636      realpow_two_le
  2637      abs_realpow_two
  2638      realpow_two_abs     
  2639 
  2640 * Theory Parity: added rules for simplifying exponents.
  2641 
  2642 * Theory List:
  2643 
  2644 The following theorems have been eliminated or modified
  2645 (INCOMPATIBILITY):
  2646 
  2647   list_all_Nil       now named list_all.simps(1)
  2648   list_all_Cons      now named list_all.simps(2)
  2649   list_all_conv      now named list_all_iff
  2650   set_mem_eq         now named mem_iff
  2651 
  2652 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  2653 asymptotic "big O" calculations.  See the notes in BigO.thy.
  2654 
  2655 
  2656 *** HOL-Complex ***
  2657 
  2658 * Theory RealDef: better support for embedding natural numbers and
  2659 integers in the reals.
  2660 
  2661 The following theorems have been eliminated or modified
  2662 (INCOMPATIBILITY):
  2663 
  2664   exp_ge_add_one_self  now requires no hypotheses
  2665   real_of_int_add      reversed direction of equality (use [symmetric])
  2666   real_of_int_minus    reversed direction of equality (use [symmetric])
  2667   real_of_int_diff     reversed direction of equality (use [symmetric])
  2668   real_of_int_mult     reversed direction of equality (use [symmetric])
  2669 
  2670 * Theory RComplete: expanded support for floor and ceiling functions.
  2671 
  2672 * Theory Ln is new, with properties of the natural logarithm
  2673 
  2674 * Hyperreal: There is a new type constructor "star" for making
  2675 nonstandard types.  The old type names are now type synonyms:
  2676 
  2677   hypreal = real star
  2678   hypnat = nat star
  2679   hcomplex = complex star
  2680 
  2681 * Hyperreal: Many groups of similarly-defined constants have been
  2682 replaced by polymorphic versions (INCOMPATIBILITY):
  2683 
  2684   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2685 
  2686   starset      <-- starsetNat, starsetC
  2687   *s*          <-- *sNat*, *sc*
  2688   starset_n    <-- starsetNat_n, starsetC_n
  2689   *sn*         <-- *sNatn*, *scn*
  2690   InternalSets <-- InternalNatSets, InternalCSets
  2691 
  2692   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2693   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2694   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2695   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2696   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2697 
  2698 * Hyperreal: Many type-specific theorems have been removed in favor of
  2699 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2700 
  2701   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2702   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2703   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2704   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2705   right_minus <-- hypreal_add_minus
  2706   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2707   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2708   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2709   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2710   mult_1_right <-- hcomplex_mult_one_right
  2711   mult_zero_left <-- hcomplex_mult_zero_left
  2712   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2713   right_distrib <-- hypnat_add_mult_distrib2
  2714   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2715   right_inverse <-- hypreal_mult_inverse
  2716   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2717   order_refl <-- {hypreal,hypnat}_le_refl
  2718   order_trans <-- {hypreal,hypnat}_le_trans
  2719   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2720   order_less_le <-- {hypreal,hypnat}_less_le
  2721   linorder_linear <-- {hypreal,hypnat}_le_linear
  2722   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2723   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2724   add_nonneg_nonneg <-- hypreal_le_add_order
  2725 
  2726 * Hyperreal: Separate theorems having to do with type-specific
  2727 versions of constants have been merged into theorems that apply to the
  2728 new polymorphic constants (INCOMPATIBILITY):
  2729 
  2730   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2731   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2732   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2733   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2734   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2735   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2736   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2737   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2738   STAR_diff <-- {STAR,STARC}_diff
  2739   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2740     STARC_hcomplex_of_complex}_image_subset
  2741   starset_n_Un <-- starset{Nat,C}_n_Un
  2742   starset_n_Int <-- starset{Nat,C}_n_Int
  2743   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2744   starset_n_diff <-- starset{Nat,C}_n_diff
  2745   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2746   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2747   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2748   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2749   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2750   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2751   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2752   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2753   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2754   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2755   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2756   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2757   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2758   starfun_diff <-- starfun{C,RC,CR}_diff
  2759   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2760   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2761   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2762   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2763   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2764   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2765   starfun_Id <-- starfunC_Id
  2766   starfun_approx <-- starfun{Nat,CR}_approx
  2767   starfun_capprox <-- starfun{C,RC}_capprox
  2768   starfun_abs <-- starfunNat_rabs
  2769   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2770   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2771   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2772   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2773   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2774   starfun_add_approx <-- starfunCR_add_approx
  2775   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2776   starfun_divide <-- starfun{C,CR,RC}_divide
  2777   starfun_n <-- starfun{Nat,C}_n
  2778   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2779   starfun_n_add <-- starfun{Nat,C}_n_add
  2780   starfun_n_add_minus <-- starfunNat_n_add_minus
  2781   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2782   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2783   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2784 
  2785   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2786   star_n_minus <-- {hypreal,hcomplex}_minus
  2787   star_n_diff <-- {hypreal,hcomplex}_diff
  2788   star_n_mult <-- {hypreal,hcomplex}_mult
  2789   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2790   star_n_le <-- {hypreal,hypnat}_le
  2791   star_n_less <-- {hypreal,hypnat}_less
  2792   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2793   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2794   star_n_abs <-- hypreal_hrabs
  2795   star_n_divide <-- hcomplex_divide
  2796 
  2797   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2798   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2799   star_of_diff <-- hypreal_of_real_diff
  2800   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2801   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2802   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2803   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2804   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2805   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2806   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2807   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2808   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2809   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2810   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2811   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2812   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2813   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2814   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2815   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2816   star_of_power <-- hypreal_of_real_power
  2817   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2818 
  2819 * Hyperreal: new method "transfer" that implements the transfer
  2820 principle of nonstandard analysis. With a subgoal that mentions
  2821 nonstandard types like "'a star", the command "apply transfer"
  2822 replaces it with an equivalent one that mentions only standard types.
  2823 To be successful, all free variables must have standard types; non-
  2824 standard variables must have explicit universal quantifiers.
  2825 
  2826 * Hyperreal: A theory of Taylor series.
  2827 
  2828 
  2829 *** HOLCF ***
  2830 
  2831 * Discontinued special version of 'constdefs' (which used to support
  2832 continuous functions) in favor of the general Pure one with full
  2833 type-inference.
  2834 
  2835 * New simplification procedure for solving continuity conditions; it
  2836 is much faster on terms with many nested lambda abstractions (cubic
  2837 instead of exponential time).
  2838 
  2839 * New syntax for domain package: selector names are now optional.
  2840 Parentheses should be omitted unless argument is lazy, for example:
  2841 
  2842   domain 'a stream = cons "'a" (lazy "'a stream")
  2843 
  2844 * New command 'fixrec' for defining recursive functions with pattern
  2845 matching; defining multiple functions with mutual recursion is also
  2846 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2847 sinr, or any data constructor defined by the domain package. The given
  2848 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2849 syntax and examples.
  2850 
  2851 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2852 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2853 but the proof obligation additionally includes an admissibility
  2854 requirement. The packages generate instances of class cpo or pcpo,
  2855 with continuity and strictness theorems for Rep and Abs.
  2856 
  2857 * HOLCF: Many theorems have been renamed according to a more standard naming
  2858 scheme (INCOMPATIBILITY):
  2859 
  2860   foo_inject:  "foo$x = foo$y ==> x = y"
  2861   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2862   foo_less:    "(foo$x << foo$y) = (x << y)"
  2863   foo_strict:  "foo$UU = UU"
  2864   foo_defined: "... ==> foo$x ~= UU"
  2865   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2866 
  2867 
  2868 *** ZF ***
  2869 
  2870 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2871 including the First Isomorphism Theorem (on quotienting by the kernel
  2872 of a homomorphism).
  2873 
  2874 * ZF/Simplifier: install second copy of type solver that actually
  2875 makes use of TC rules declared to Isar proof contexts (or locales);
  2876 the old version is still required for ML proof scripts.
  2877 
  2878 
  2879 *** Cube ***
  2880 
  2881 * Converted to Isar theory format; use locales instead of axiomatic
  2882 theories.
  2883 
  2884 
  2885 *** ML ***
  2886 
  2887 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2888 for ||>, ||>>, |>>,
  2889 
  2890 * Pure/library.ML no longer defines its own option datatype, but uses
  2891 that of the SML basis, which has constructors NONE and SOME instead of
  2892 None and Some, as well as exception Option.Option instead of OPTION.
  2893 The functions the, if_none, is_some, is_none have been adapted
  2894 accordingly, while Option.map replaces apsome.
  2895 
  2896 * Pure/library.ML: the exception LIST has been given up in favour of
  2897 the standard exceptions Empty and Subscript, as well as
  2898 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2899 superceded by the standard hd and tl functions etc.
  2900 
  2901 A number of basic list functions are no longer exported to the ML
  2902 toplevel, as they are variants of predefined functions.  The following
  2903 suggests how one can translate existing code:
  2904 
  2905     rev_append xs ys = List.revAppend (xs, ys)
  2906     nth_elem (i, xs) = List.nth (xs, i)
  2907     last_elem xs = List.last xs
  2908     flat xss = List.concat xss
  2909     seq fs = List.app fs
  2910     partition P xs = List.partition P xs
  2911     mapfilter f xs = List.mapPartial f xs
  2912 
  2913 * Pure/library.ML: several combinators for linear functional
  2914 transformations, notably reverse application and composition:
  2915 
  2916   x |> f                f #> g
  2917   (x, y) |-> f          f #-> g
  2918 
  2919 * Pure/library.ML: introduced/changed precedence of infix operators:
  2920 
  2921   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2922   infix 2 ?;
  2923   infix 3 o oo ooo oooo;
  2924   infix 4 ~~ upto downto;
  2925 
  2926 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2927 infix operators.
  2928 
  2929 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2930 fold_map support linear functional transformations and nesting.  For
  2931 example:
  2932 
  2933   fold f [x1, ..., xN] y =
  2934     y |> f x1 |> ... |> f xN
  2935 
  2936   (fold o fold) f [xs1, ..., xsN] y =
  2937     y |> fold f xs1 |> ... |> fold f xsN
  2938 
  2939   fold f [x1, ..., xN] =
  2940     f x1 #> ... #> f xN
  2941 
  2942   (fold o fold) f [xs1, ..., xsN] =
  2943     fold f xs1 #> ... #> fold f xsN
  2944 
  2945 * Pure/library.ML: the following selectors on type 'a option are
  2946 available:
  2947 
  2948   the:               'a option -> 'a  (*partial*)
  2949   these:             'a option -> 'a  where 'a = 'b list
  2950   the_default: 'a -> 'a option -> 'a
  2951   the_list:          'a option -> 'a list
  2952 
  2953 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2954 basic operations for association lists, following natural argument
  2955 order; moreover the explicit equality predicate passed here avoids
  2956 potentially expensive polymorphic runtime equality checks.
  2957 The old functions may be expressed as follows:
  2958 
  2959   assoc = uncurry (AList.lookup (op =))
  2960   assocs = these oo AList.lookup (op =)
  2961   overwrite = uncurry (AList.update (op =)) o swap
  2962 
  2963 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2964 
  2965   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2966   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2967 
  2968 replacing make_keylist and keyfilter (occassionally used)
  2969 Naive rewrites:
  2970 
  2971   make_keylist = AList.make
  2972   keyfilter = AList.find (op =)
  2973 
  2974 * eq_fst and eq_snd now take explicit equality parameter, thus
  2975   avoiding eqtypes. Naive rewrites:
  2976 
  2977     eq_fst = eq_fst (op =)
  2978     eq_snd = eq_snd (op =)
  2979 
  2980 * Removed deprecated apl and apr (rarely used).
  2981   Naive rewrites:
  2982 
  2983     apl (n, op) =>>= curry op n
  2984     apr (op, m) =>>= fn n => op (n, m)
  2985 
  2986 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2987 provides a reasonably efficient light-weight implementation of sets as
  2988 lists.
  2989 
  2990 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2991 few new operations; existing lookup and update are now curried to
  2992 follow natural argument order (for use with fold etc.);
  2993 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2994 
  2995 * Pure/General: output via the Isabelle channels of
  2996 writeln/warning/error etc. is now passed through Output.output, with a
  2997 hook for arbitrary transformations depending on the print_mode
  2998 (cf. Output.add_mode -- the first active mode that provides a output
  2999 function wins).  Already formatted output may be embedded into further
  3000 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3001 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3002 accommodate easy composition of diagnostic messages etc.  Programmers
  3003 rarely need to care about Output.output or Output.raw at all, with
  3004 some notable exceptions: Output.output is required when bypassing the
  3005 standard channels (writeln etc.), or in token translations to produce
  3006 properly formatted results; Output.raw is required when capturing
  3007 already output material that will eventually be presented to the user
  3008 a second time.  For the default print mode, both Output.output and
  3009 Output.raw have no effect.
  3010 
  3011 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3012 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3013 cumulative results are displayed at the end of a batch session.
  3014 
  3015 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3016 replaced by File.platform_path and File.shell_path (with appropriate
  3017 hooks).  This provides a clean interface for unusual systems where the
  3018 internal and external process view of file names are different.
  3019 
  3020 * Pure: more efficient orders for basic syntactic entities: added
  3021 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3022 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3023 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3024 orders now -- potential INCOMPATIBILITY for code that depends on a
  3025 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3026 Library.sort_strings on result).
  3027 
  3028 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3029 fold_types traverse types/terms from left to right, observing natural
  3030 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3031 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3032 
  3033 * Pure: name spaces have been refined, with significant changes of the
  3034 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3035 to extern(_table).  The plain name entry path is superceded by a
  3036 general 'naming' context, which also includes the 'policy' to produce
  3037 a fully qualified name and external accesses of a fully qualified
  3038 name; NameSpace.extend is superceded by context dependent
  3039 Sign.declare_name.  Several theory and proof context operations modify
  3040 the naming context.  Especially note Theory.restore_naming and
  3041 ProofContext.restore_naming to get back to a sane state; note that
  3042 Theory.add_path is no longer sufficient to recover from
  3043 Theory.absolute_path in particular.
  3044 
  3045 * Pure: new flags short_names (default false) and unique_names
  3046 (default true) for controlling output of qualified names.  If
  3047 short_names is set, names are printed unqualified.  If unique_names is
  3048 reset, the name prefix is reduced to the minimum required to achieve
  3049 the original result when interning again, even if there is an overlap
  3050 with earlier declarations.
  3051 
  3052 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3053 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3054 (useful for printing error messages).  INCOMPATIBILITY.
  3055 
  3056 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3057 Theory.theory are now identified, referring to the universal
  3058 Context.theory (see Pure/context.ML).  Actual signature and theory
  3059 content is managed as theory data.  The old code and interfaces were
  3060 spread over many files and structures; the new arrangement introduces
  3061 considerable INCOMPATIBILITY to gain more clarity:
  3062 
  3063   Context -- theory management operations (name, identity, inclusion,
  3064     parents, ancestors, merge, etc.), plus generic theory data;
  3065 
  3066   Sign -- logical signature and syntax operations (declaring consts,
  3067     types, etc.), plus certify/read for common entities;
  3068 
  3069   Theory -- logical theory operations (stating axioms, definitions,
  3070     oracles), plus a copy of logical signature operations (consts,
  3071     types, etc.); also a few basic management operations (Theory.copy,
  3072     Theory.merge, etc.)
  3073 
  3074 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3075 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3076 for convenience -- they merely return the theory.
  3077 
  3078 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3079 
  3080 * Pure: the Isar proof context type is already defined early in Pure
  3081 as Context.proof (note that ProofContext.context and Proof.context are
  3082 aliases, where the latter is the preferred name).  This enables other
  3083 Isabelle components to refer to that type even before Isar is present.
  3084 
  3085 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3086 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3087 any of these kinds.  For example, Sign.intern typeK is now
  3088 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3089 Theory.hide_types.  Also note that former
  3090 Theory.hide_classes/types/consts are now
  3091 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3092 internalize their arguments!  INCOMPATIBILITY.
  3093 
  3094 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3095 datatype thmref (with constructors Name and NameSelection) instead of
  3096 plain string -- INCOMPATIBILITY;
  3097 
  3098 * Pure: cases produced by proof methods specify options, where NONE
  3099 means to remove case bindings -- INCOMPATIBILITY in
  3100 (RAW_)METHOD_CASES.
  3101 
  3102 * Pure: the following operations retrieve axioms or theorems from a
  3103 theory node or theory hierarchy, respectively:
  3104 
  3105   Theory.axioms_of: theory -> (string * term) list
  3106   Theory.all_axioms_of: theory -> (string * term) list
  3107   PureThy.thms_of: theory -> (string * thm) list
  3108   PureThy.all_thms_of: theory -> (string * thm) list
  3109 
  3110 * Pure: print_tac now outputs the goal through the trace channel.
  3111 
  3112 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3113 Reference Toplevel.debug (default false) controls detailed printing
  3114 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3115 controls execution profiling -- set to 1 for time and 2 for space
  3116 (both increase the runtime).
  3117 
  3118 * Isar session: The initial use of ROOT.ML is now always timed,
  3119 i.e. the log will show the actual process times, in contrast to the
  3120 elapsed wall-clock time that the outer shell wrapper produces.
  3121 
  3122 * Simplifier: improved handling of bound variables (nameless
  3123 representation, avoid allocating new strings).  Simprocs that invoke
  3124 the Simplifier recursively should use Simplifier.inherit_bounds to
  3125 avoid local name clashes.  Failure to do so produces warnings
  3126 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3127 for further details.
  3128 
  3129 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3130 bindings for all theorems stored within a given theory; this may help
  3131 in porting non-Isar theories to Isar ones, while keeping ML proof
  3132 scripts for the time being.
  3133 
  3134 * ML operator HTML.with_charset specifies the charset begin used for
  3135 generated HTML files.  For example:
  3136 
  3137   HTML.with_charset "utf-8" use_thy "Hebrew";
  3138   HTML.with_charset "utf-8" use_thy "Chinese";
  3139 
  3140 
  3141 *** System ***
  3142 
  3143 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3144 isabelle, isatool etc.).
  3145 
  3146 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3147 isatool doc, isatool mkdir, display_drafts etc.).
  3148 
  3149 * isatool usedir: option -f allows specification of the ML file to be
  3150 used by Isabelle; default is ROOT.ML.
  3151 
  3152 * New isatool version outputs the version identifier of the Isabelle
  3153 distribution being used.
  3154 
  3155 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3156 (containing Boolean satisfiability problems) into Isabelle/HOL
  3157 theories.
  3158 
  3159 
  3160 
  3161 New in Isabelle2004 (April 2004)
  3162 --------------------------------
  3163 
  3164 *** General ***
  3165 
  3166 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3167   Replaces linorder.ML.
  3168 
  3169 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3170   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3171   (\<a>...\<z>), are now considered normal letters, and can therefore
  3172   be used anywhere where an ASCII letter (a...zA...Z) has until
  3173   now. COMPATIBILITY: This obviously changes the parsing of some
  3174   terms, especially where a symbol has been used as a binder, say
  3175   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3176   as an identifier.  Fix it by inserting a space around former
  3177   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3178   existing theory and ML files.
  3179 
  3180 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3181 
  3182 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3183   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3184   a normal (but invisible) letter. For multiple letter subscripts repeat
  3185   \<^isub> like this: x\<^isub>1\<^isub>2.
  3186 
  3187 * Pure: There are now sub-/superscripts that can span more than one
  3188   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3189   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3190   superscript. The new control characters are not identifier parts.
  3191 
  3192 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3193   content of "..." to the latex file instead of \isacntrl... . The "..."
  3194   may consist of any printable characters excluding the end bracket >.
  3195 
  3196 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3197   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3198   declare constants "final", which prevents their being given a definition
  3199   later.  It is useful for constants whose behaviour is fixed axiomatically
  3200   rather than definitionally, such as the meta-logic connectives.
  3201 
  3202 * Pure: 'instance' now handles general arities with general sorts
  3203   (i.e. intersections of classes),
  3204 
  3205 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3206   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3207   It can be changed to alter the colors/layout of generated pages.
  3208 
  3209 
  3210 *** Isar ***
  3211 
  3212 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3213   cut_tac, subgoal_tac and thin_tac:
  3214   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3215     locales are no longer forced to write Isar proof scripts.
  3216     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3217     emulations.
  3218   - INCOMPATIBILITY: names of variables to be instantiated may no
  3219     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3220     This is consistent with the instantiation attribute "where".
  3221 
  3222 * Attributes "where" and "of":
  3223   - Now take type variables of instantiated theorem into account when reading
  3224     the instantiation string.  This fixes a bug that caused instantiated
  3225     theorems to have too special types in some circumstances.
  3226   - "where" permits explicit instantiations of type variables.
  3227 
  3228 * Calculation commands "moreover" and "also" no longer interfere with
  3229   current facts ("this"), admitting arbitrary combinations with "then"
  3230   and derived forms.
  3231 
  3232 * Locales:
  3233   - Goal statements involving the context element "includes" no longer
  3234     generate theorems with internal delta predicates (those ending on
  3235     "_axioms") in the premise.
  3236     Resolve particular premise with <locale>.intro to obtain old form.
  3237   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3238     specification and "includes" elements in goal statement.
  3239   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3240     [intro?] and [elim?] (respectively) by default.
  3241   - Experimental command for instantiation of locales in proof contexts:
  3242         instantiate <label>[<attrs>]: <loc>
  3243     Instantiates locale <loc> and adds all its theorems to the current context
  3244     taking into account their attributes.  Label and attrs are optional
  3245     modifiers, like in theorem declarations.  If present, names of
  3246     instantiated theorems are qualified with <label>, and the attributes
  3247     <attrs> are applied after any attributes these theorems might have already.
  3248       If the locale has assumptions, a chained fact of the form
  3249     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3250     are derived.  The command does not support old-style locales declared
  3251     with "locale (open)".
  3252       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3253 
  3254 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3255   (Isar) contexts.
  3256 
  3257 
  3258 *** HOL ***
  3259 
  3260 * Proof import: new image HOL4 contains the imported library from
  3261   the HOL4 system with about 2500 theorems. It is imported by
  3262   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3263   can be used like any other Isabelle image.  See
  3264   HOL/Import/HOL/README for more information.
  3265 
  3266 * Simplifier:
  3267   - Much improved handling of linear and partial orders.
  3268     Reasoners for linear and partial orders are set up for type classes
  3269     "linorder" and "order" respectively, and are added to the default simpset
  3270     as solvers.  This means that the simplifier can build transitivity chains
  3271     to solve goals from the assumptions.
  3272   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3273     of blast or auto after simplification become unnecessary because the goal
  3274     is solved by simplification already.
  3275 
  3276 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3277     all proved in axiomatic type classes for semirings, rings and fields.
  3278 
  3279 * Numerics:
  3280   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3281     now formalized using the Ring_and_Field theory mentioned above.
  3282   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3283     than before, because now they are set up once in a generic manner.
  3284   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3285     Look for the general versions in Ring_and_Field (and Power if they concern
  3286     exponentiation).
  3287 
  3288 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3289 
  3290 * Records:
  3291   - Record types are now by default printed with their type abbreviation
  3292     instead of the list of all field types. This can be configured via
  3293     the reference "print_record_type_abbr".
  3294   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3295     (not enabled by default).
  3296   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3297     EX x. x = sel r to True (not enabled by default).
  3298   - Tactic "record_split_simp_tac" to split and simplify records added.
  3299 
  3300 * 'specification' command added, allowing for definition by
  3301   specification.  There is also an 'ax_specification' command that
  3302   introduces the new constants axiomatically.
  3303 
  3304 * arith(_tac) is now able to generate counterexamples for reals as well.
  3305 
  3306 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3307 
  3308 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3309   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3310 
  3311 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3312   matrix theory to linear programming.
  3313 
  3314 * Unions and Intersections:
  3315   The latex output syntax of UN and INT has been changed
  3316   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3317   i.e. the index formulae has become a subscript.
  3318   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3319 
  3320 * Unions and Intersections over Intervals:
  3321   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3322   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3323   like in normal math, and corresponding versions for < and for intersection.
  3324 
  3325 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3326   lexicographic dictonary ordering has been added as "lexord".
  3327 
  3328 * ML: the legacy theory structures Int and List have been removed. They had
  3329   conflicted with ML Basis Library structures having the same names.
  3330 
  3331 * 'refute' command added to search for (finite) countermodels.  Only works
  3332   for a fragment of HOL.  The installation of an external SAT solver is
  3333   highly recommended.  See "HOL/Refute.thy" for details.
  3334 
  3335 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3336   formulae under an assignment of free variables to random values.
  3337   In contrast to 'refute', it can deal with inductive datatypes,
  3338   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3339   for examples.
  3340 
  3341 
  3342 *** HOLCF ***
  3343 
  3344 * Streams now come with concatenation and are part of the HOLCF image
  3345 
  3346 
  3347 
  3348 New in Isabelle2003 (May 2003)
  3349 ------------------------------
  3350 
  3351 *** General ***
  3352 
  3353 * Provers/simplifier:
  3354 
  3355   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3356     Assumptions are now subject to complete mutual simplification,
  3357     not just from left to right. The simplifier now preserves
  3358     the order of assumptions.
  3359 
  3360     Potential INCOMPATIBILITY:
  3361 
  3362     -- simp sometimes diverges where the old version did
  3363        not, e.g. invoking simp on the goal
  3364 
  3365         [| P (f x); y = x; f x = f y |] ==> Q
  3366 
  3367        now gives rise to the infinite reduction sequence
  3368 
  3369         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3370 
  3371        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3372        kind of problem.
  3373 
  3374     -- Tactics combining classical reasoner and simplification (such as auto)
  3375        are also affected by this change, because many of them rely on
  3376        simp. They may sometimes diverge as well or yield a different numbers
  3377        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3378        in case of problems. Sometimes subsequent calls to the classical
  3379        reasoner will fail because a preceeding call to the simplifier too
  3380        eagerly simplified the goal, e.g. deleted redundant premises.
  3381 
  3382   - The simplifier trace now shows the names of the applied rewrite rules
  3383 
  3384   - You can limit the number of recursive invocations of the simplifier
  3385     during conditional rewriting (where the simplifie tries to solve the
  3386     conditions before applying the rewrite rule):
  3387     ML "simp_depth_limit := n"
  3388     where n is an integer. Thus you can force termination where previously
  3389     the simplifier would diverge.
  3390 
  3391   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3392 
  3393   - No longer aborts on failed congruence proof.  Instead, the
  3394     congruence is ignored.
  3395 
  3396 * Pure: New generic framework for extracting programs from constructive
  3397   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3398   as HOL/Extraction for some case studies.
  3399 
  3400 * Pure: The main goal of the proof state is no longer shown by default, only
  3401 the subgoals. This behaviour is controlled by a new flag.
  3402    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3403 (ML: Proof.show_main_goal).
  3404 
  3405 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3406 rules whose conclusion matches subgoal 1:
  3407       PG menu: Isabelle/Isar -> Show me -> matching rules
  3408 The rules are ordered by how closely they match the subgoal.
  3409 In particular, rules that solve a subgoal outright are displayed first
  3410 (or rather last, the way they are printed).
  3411 (ML: ProofGeneral.print_intros())
  3412 
  3413 * Pure: New flag trace_unify_fail causes unification to print
  3414 diagnostic information (PG: in trace buffer) when it fails. This is
  3415 useful for figuring out why single step proofs like rule, erule or
  3416 assumption failed.
  3417 
  3418 * Pure: Locale specifications now produce predicate definitions
  3419 according to the body of text (covering assumptions modulo local
  3420 definitions); predicate "loc_axioms" covers newly introduced text,
  3421 while "loc" is cumulative wrt. all included locale expressions; the
  3422 latter view is presented only on export into the global theory
  3423 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3424 on the old view without predicates;
  3425 
  3426 * Pure: predefined locales "var" and "struct" are useful for sharing
  3427 parameters (as in CASL, for example); just specify something like
  3428 ``var x + var y + struct M'' as import;
  3429 
  3430 * Pure: improved thms_containing: proper indexing of facts instead of
  3431 raw theorems; check validity of results wrt. current name space;
  3432 include local facts of proof configuration (also covers active
  3433 locales), cover fixed variables in index; may use "_" in term
  3434 specification; an optional limit for the number of printed facts may
  3435 be given (the default is 40);
  3436 
  3437 * Pure: disallow duplicate fact bindings within new-style theory files
  3438 (batch-mode only);
  3439 
  3440 * Provers: improved induct method: assumptions introduced by case
  3441 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3442 the goal statement); "foo" still refers to all facts collectively;
  3443 
  3444 * Provers: the function blast.overloaded has been removed: all constants
  3445 are regarded as potentially overloaded, which improves robustness in exchange
  3446 for slight decrease in efficiency;
  3447 
  3448 * Provers/linorder: New generic prover for transitivity reasoning over
  3449 linear orders.  Note: this prover is not efficient!
  3450 
  3451 * Isar: preview of problems to finish 'show' now produce an error
  3452 rather than just a warning (in interactive mode);
  3453 
  3454 
  3455 *** HOL ***
  3456 
  3457 * arith(_tac)
  3458 
  3459  - Produces a counter example if it cannot prove a goal.
  3460    Note that the counter example may be spurious if the goal is not a formula
  3461    of quantifier-free linear arithmetic.
  3462    In ProofGeneral the counter example appears in the trace buffer.
  3463 
  3464  - Knows about div k and mod k where k is a numeral of type nat or int.
  3465 
  3466  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3467    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3468    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3469 
  3470 * simp's arithmetic capabilities have been enhanced a bit: it now
  3471 takes ~= in premises into account (by performing a case split);
  3472 
  3473 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3474 are distributed over a sum of terms;
  3475 
  3476 * New tactic "trans_tac" and method "trans" instantiate
  3477 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3478 "<=", "<" and "=").
  3479 
  3480 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3481 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3482 
  3483 * 'typedef' command has new option "open" to suppress the set
  3484 definition;
  3485 
  3486 * functions Min and Max on finite sets have been introduced (theory
  3487 Finite_Set);
  3488 
  3489 * attribute [symmetric] now works for relations as well; it turns
  3490 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3491 
  3492 * induct over a !!-quantified statement (say !!x1..xn):
  3493   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3494 
  3495 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3496 %x. None. Warning: empty_def now refers to the previously hidden definition
  3497 of the empty set.
  3498 
  3499 * Algebra: formalization of classical algebra.  Intended as base for
  3500 any algebraic development in Isabelle.  Currently covers group theory
  3501 (up to Sylow's theorem) and ring theory (Universal Property of
  3502 Univariate Polynomials).  Contributions welcome;
  3503 
  3504 * GroupTheory: deleted, since its material has been moved to Algebra;
  3505 
  3506 * Complex: new directory of the complex numbers with numeric constants,
  3507 nonstandard complex numbers, and some complex analysis, standard and
  3508 nonstandard (Jacques Fleuriot);
  3509 
  3510 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3511 
  3512 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3513 Fleuriot);
  3514 
  3515 * Real/HahnBanach: updated and adapted to locales;
  3516 
  3517 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3518 Gray and Kramer);
  3519 
  3520 * UNITY: added the Meier-Sanders theory of progress sets;
  3521 
  3522 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3523 as abstract algorithms, instantiated to the JVM;
  3524 
  3525 * Bali: Java source language formalization. Type system, operational
  3526 semantics, axiomatic semantics. Supported language features:
  3527 classes, interfaces, objects,virtual methods, static methods,
  3528 static/instance fields, arrays, access modifiers, definite
  3529 assignment, exceptions.
  3530 
  3531 
  3532 *** ZF ***
  3533 
  3534 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3535 universe, etc.);
  3536 
  3537 * Main ZF: virtually all theories converted to new-style format;
  3538 
  3539 
  3540 *** ML ***
  3541 
  3542 * Pure: Tactic.prove provides sane interface for internal proofs;
  3543 omits the infamous "standard" operation, so this is more appropriate
  3544 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3545 
  3546 * Pure: improved error reporting of simprocs;
  3547 
  3548 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3549 up simprocs;
  3550 
  3551 
  3552 *** Document preparation ***
  3553 
  3554 * uses \par instead of \\ for line breaks in theory text. This may
  3555 shift some page breaks in large documents. To get the old behaviour
  3556 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3557 
  3558 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3559 other packages
  3560 
  3561 * \<euro> now needs package babel/greek instead of marvosym (which
  3562 broke \Rightarrow)
  3563 
  3564 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3565 textcomp package)
  3566 
  3567 
  3568 
  3569 New in Isabelle2002 (March 2002)
  3570 --------------------------------
  3571 
  3572 *** Document preparation ***
  3573 
  3574 * greatly simplified document preparation setup, including more
  3575 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3576 instructive isatool mkdir; users should basically be able to get
  3577 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3578 users may run a separate document processing stage manually like this:
  3579 "isatool usedir -D output HOL Test && isatool document Test/output";
  3580 
  3581 * theory dependency graph may now be incorporated into documents;
  3582 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3583 with \includegraphics of LaTeX;
  3584 
  3585 * proper spacing of consecutive markup elements, especially text
  3586 blocks after section headings;
  3587 
  3588 * support bold style (for single symbols only), input syntax is like
  3589 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3590 
  3591 * \<bullet> is now output as bold \cdot by default, which looks much
  3592 better in printed text;
  3593 
  3594 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3595 note that these symbols are currently unavailable in Proof General /
  3596 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3597 
  3598 * isatool latex no longer depends on changed TEXINPUTS, instead
  3599 isatool document copies the Isabelle style files to the target
  3600 location;
  3601 
  3602 
  3603 *** Isar ***
  3604 
  3605 * Pure/Provers: improved proof by cases and induction;
  3606   - 'case' command admits impromptu naming of parameters (such as
  3607     "case (Suc n)");
  3608   - 'induct' method divinates rule instantiation from the inductive
  3609     claim; no longer requires excessive ?P bindings for proper
  3610     instantiation of cases;
  3611   - 'induct' method properly enumerates all possibilities of set/type
  3612     rules; as a consequence facts may be also passed through *type*
  3613     rules without further ado;
  3614   - 'induct' method now derives symbolic cases from the *rulified*
  3615     rule (before it used to rulify cases stemming from the internal
  3616     atomized version); this means that the context of a non-atomic
  3617     statement becomes is included in the hypothesis, avoiding the
  3618     slightly cumbersome show "PROP ?case" form;
  3619   - 'induct' may now use elim-style induction rules without chaining
  3620     facts, using ``missing'' premises from the goal state; this allows
  3621     rules stemming from inductive sets to be applied in unstructured
  3622     scripts, while still benefitting from proper handling of non-atomic
  3623     statements; NB: major inductive premises need to be put first, all
  3624     the rest of the goal is passed through the induction;
  3625   - 'induct' proper support for mutual induction involving non-atomic
  3626     rule statements (uses the new concept of simultaneous goals, see
  3627     below);
  3628   - append all possible rule selections, but only use the first
  3629     success (no backtracking);
  3630   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3631   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3632   - added 'print_induct_rules' (covered by help item in recent Proof
  3633     General versions);
  3634   - moved induct/cases attributes to Pure, methods to Provers;
  3635   - generic method setup instantiated for FOL and HOL;
  3636 
  3637 * Pure: support multiple simultaneous goal statements, for example
  3638 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3639 meta-level mechanism, this acts as if several individual goals had
  3640 been stated separately; in particular common proof methods need to be
  3641 repeated in order to cover all claims; note that a single elimination
  3642 step is *not* sufficient to establish the two conjunctions, so this
  3643 fails:
  3644 
  3645   assume "A & B" then have A and B ..   (*".." fails*)
  3646 
  3647 better use "obtain" in situations as above; alternative refer to
  3648 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  3649 
  3650 * Pure: proper integration with ``locales''; unlike the original
  3651 version by Florian Kammller, Isar locales package high-level proof
  3652 contexts rather than raw logical ones (e.g. we admit to include
  3653 attributes everywhere); operations on locales include merge and
  3654 rename; support for implicit arguments (``structures''); simultaneous
  3655 type-inference over imports and text; see also HOL/ex/Locales.thy for
  3656 some examples;
  3657 
  3658 * Pure: the following commands have been ``localized'', supporting a
  3659 target locale specification "(in name)": 'lemma', 'theorem',
  3660 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  3661 stored both within the locale and at the theory level (exported and
  3662 qualified by the locale name);
  3663 
  3664 * Pure: theory goals may now be specified in ``long'' form, with
  3665 ad-hoc contexts consisting of arbitrary locale elements. for example
  3666 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  3667 definitions may be given, too); the result is a meta-level rule with
  3668 the context elements being discharged in the obvious way;
  3669 
  3670 * Pure: new proof command 'using' allows to augment currently used
  3671 facts after a goal statement ('using' is syntactically analogous to
  3672 'apply', but acts on the goal's facts only); this allows chained facts
  3673 to be separated into parts given before and after a claim, as in
  3674 ``from a and b have C using d and e <proof>'';
  3675 
  3676 * Pure: renamed "antecedent" case to "rule_context";
  3677 
  3678 * Pure: new 'judgment' command records explicit information about the
  3679 object-logic embedding (used by several tools internally); no longer
  3680 use hard-wired "Trueprop";
  3681 
  3682 * Pure: added 'corollary' command;
  3683 
  3684 * Pure: fixed 'token_translation' command;
  3685 
  3686 * Pure: removed obsolete 'exported' attribute;
  3687 
  3688 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3689 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3690 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3691 
  3692 * Pure: method 'atomize' presents local goal premises as object-level
  3693 statements (atomic meta-level propositions); setup controlled via
  3694 rewrite rules declarations of 'atomize' attribute; example
  3695 application: 'induct' method with proper rule statements in improper
  3696 proof *scripts*;
  3697 
  3698 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3699 now consider the syntactic context of assumptions, giving a better
  3700 chance to get type-inference of the arguments right (this is
  3701 especially important for locales);
  3702 
  3703 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3704 mode;
  3705 
  3706 * Pure/obtain: the formal conclusion "thesis", being marked as
  3707 ``internal'', may no longer be reference directly in the text;
  3708 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3709 situations;
  3710 
  3711 * Pure: generic 'sym' attribute which declares a rule both as pure
  3712 'elim?' and for the 'symmetric' operation;
  3713 
  3714 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3715 text; the fixed correlation with particular command syntax has been
  3716 discontinued;
  3717 
  3718 * Pure: new method 'rules' is particularly well-suited for proof
  3719 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3720 but often produces more compact proof terms with less detours;
  3721 
  3722 * Pure/Provers/classical: simplified integration with pure rule
  3723 attributes and methods; the classical "intro?/elim?/dest?"
  3724 declarations coincide with the pure ones; the "rule" method no longer
  3725 includes classically swapped intros; "intro" and "elim" methods no
  3726 longer pick rules from the context; also got rid of ML declarations
  3727 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3728 INCOMPATIBILITY;
  3729 
  3730 * Provers/classical: attribute 'swapped' produces classical inversions
  3731 of introduction rules;
  3732 
  3733 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3734 rules instead of full simplifier context; 'iff' attribute handles
  3735 conditional rules;
  3736 
  3737 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3738 
  3739 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3740 "(permissive)" option to recover old behavior;
  3741 
  3742 * HOL: 'inductive' no longer features separate (collective) attributes
  3743 for 'intros' (was found too confusing);
  3744 
  3745 * HOL: properly declared induction rules less_induct and
  3746 wf_induct_rule;
  3747 
  3748 
  3749 *** HOL ***
  3750 
  3751 * HOL: moved over to sane numeral syntax; the new policy is as
  3752 follows:
  3753 
  3754   - 0 and 1 are polymorphic constants, which are defined on any
  3755   numeric type (nat, int, real etc.);
  3756 
  3757   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3758   binary representation internally;
  3759 
  3760   - type nat has special constructor Suc, and generally prefers Suc 0
  3761   over 1::nat and Suc (Suc 0) over 2::nat;
  3762 
  3763 This change may cause significant problems of INCOMPATIBILITY; here
  3764 are some hints on converting existing sources:
  3765 
  3766   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3767   entities, so expressions involving "-" (unary or binary minus) need
  3768   to be spaced properly;
  3769 
  3770   - existing occurrences of "1" may need to be constraint "1::nat" or
  3771   even replaced by Suc 0; similar for old "2";
  3772 
  3773   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3774 
  3775   - remove all special provisions on numerals in proofs;
  3776 
  3777 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3778 representation (depends on bin_arith_simps in the default context);
  3779 
  3780 * HOL: symbolic syntax for x^2 (numeral 2);
  3781 
  3782 * HOL: the class of all HOL types is now called "type" rather than
  3783 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3784 in axclass/classes, instance/arities, and (usually rare) occurrences
  3785 in typings (of consts etc.); internally the class is called
  3786 "HOL.type", ML programs should refer to HOLogic.typeS;
  3787 
  3788 * HOL/record package improvements:
  3789   - new derived operations "fields" to build a partial record section,
  3790     "extend" to promote a fixed record to a record scheme, and
  3791     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3792     declared as simp by default;
  3793   - shared operations ("more", "fields", etc.) now need to be always
  3794     qualified) --- potential INCOMPATIBILITY;
  3795   - removed "make_scheme" operations (use "make" with "extend") --
  3796     INCOMPATIBILITY;
  3797   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3798   - provides cases/induct rules for use with corresponding Isar
  3799     methods (for concrete records, record schemes, concrete more
  3800     parts, and schematic more parts -- in that order);
  3801   - internal definitions directly based on a light-weight abstract
  3802     theory of product types over typedef rather than datatype;
  3803 
  3804 * HOL: generic code generator for generating executable ML code from
  3805 specifications; specific support for HOL constructs such as inductive
  3806 datatypes and sets, as well as recursive functions; can be invoked
  3807 via 'generate_code' theory section;
  3808 
  3809 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3810 
  3811 * HOL: consolidated and renamed several theories.  In particular:
  3812         Ord.thy has been absorbed into HOL.thy
  3813         String.thy has been absorbed into List.thy
  3814 
  3815 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3816 (beware of argument permutation!);
  3817 
  3818 * HOL: linorder_less_split superseded by linorder_cases;
  3819 
  3820 * HOL/List: "nodups" renamed to "distinct";
  3821 
  3822 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3823 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3824   - Ex_def has changed, now need to use some_eq_ex
  3825 
  3826 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3827 in this (rare) case use:
  3828 
  3829   delSWrapper "split_all_tac"
  3830   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3831 
  3832 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3833 MAY FAIL;
  3834 
  3835 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3836 Isabelle's type classes, ^ on functions and relations has too general
  3837 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3838 necessary to attach explicit type constraints;
  3839 
  3840 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3841 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3842 renamed accordingly (eg "compI" -> "rel_compI").
  3843 
  3844 * HOL: syntax translations now work properly with numerals and records
  3845 expressions;
  3846 
  3847 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3848 of "lam" -- INCOMPATIBILITY;
  3849 
  3850 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3851 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3852 renamed "Product_Type.unit";
  3853 
  3854 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3855 
  3856 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3857 the "cases" method);
  3858 
  3859 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3860 Florian Kammller);
  3861 
  3862 * HOL/IMP: updated and converted to new-style theory format; several
  3863 parts turned into readable document, with proper Isar proof texts and
  3864 some explanations (by Gerwin Klein);
  3865 
  3866 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3867 
  3868 * HOL-Hyperreal is now a logic image;
  3869 
  3870 
  3871 *** HOLCF ***
  3872 
  3873 * Isar: consts/constdefs supports mixfix syntax for continuous
  3874 operations;
  3875 
  3876 * Isar: domain package adapted to new-style theory format, e.g. see
  3877 HOLCF/ex/Dnat.thy;
  3878 
  3879 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3880 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3881 lift.induct_tac, always use UU instead of Undef;
  3882 
  3883 * HOLCF/IMP: updated and converted to new-style theory;
  3884 
  3885 
  3886 *** ZF ***
  3887 
  3888 * Isar: proper integration of logic-specific tools and packages,
  3889 including theory commands '(co)inductive', '(co)datatype',
  3890 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3891 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3892 
  3893 * theory Main no longer includes AC; for the Axiom of Choice, base
  3894 your theory on Main_ZFC;
  3895 
  3896 * the integer library now covers quotients and remainders, with many
  3897 laws relating division to addition, multiplication, etc.;
  3898 
  3899 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3900 typeless version of the formalism;
  3901 
  3902 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3903 format;
  3904 
  3905 * ZF/Induct: new directory for examples of inductive definitions,
  3906 including theory Multiset for multiset orderings; converted to
  3907 new-style theory format;
  3908 
  3909 * ZF: many new theorems about lists, ordinals, etc.;
  3910 
  3911 
  3912 *** General ***
  3913 
  3914 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3915 variable proof controls level of detail: 0 = no proofs (only oracle
  3916 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3917 also ref manual for further ML interfaces;
  3918 
  3919 * Pure/axclass: removed obsolete ML interface
  3920 goal_subclass/goal_arity;
  3921 
  3922 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3923 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3924 separate tokens, so expressions involving minus need to be spaced
  3925 properly;
  3926 
  3927 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3928 rather than "infixl" or "infixr";
  3929 
  3930 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3931 sort constraint specifications in type inference; e.g. "x::_::foo"
  3932 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3933 type variable);
  3934 
  3935 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3936 control output of nested => (types); the default behavior is
  3937 "type_brackets";
  3938 
  3939 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3940 tokens into AST constants;
  3941 
  3942 * Pure/syntax: prefer later declarations of translations and print
  3943 translation functions; potential INCOMPATIBILITY: need to reverse
  3944 multiple declarations for same syntax element constant;
  3945 
  3946 * Pure/show_hyps reset by default (in accordance to existing Isar
  3947 practice);
  3948 
  3949 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3950 addSafter;
  3951 
  3952 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3953 as well;
  3954 
  3955 * system: tested support for MacOS X; should be able to get Isabelle +
  3956 Proof General to work in a plain Terminal after installing Poly/ML
  3957 (e.g. from the Isabelle distribution area) and GNU bash alone
  3958 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3959 support requires further installations, e.g. from
  3960 http://fink.sourceforge.net/);
  3961 
  3962 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3963 
  3964 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3965 of 40 MB), cf. ML_OPTIONS;
  3966 
  3967 * system: Proof General keywords specification is now part of the
  3968 Isabelle distribution (see etc/isar-keywords.el);
  3969 
  3970 * system: support for persistent Proof General sessions (refrain from
  3971 outdating all loaded theories on startup); user may create writable
  3972 logic images like this: ``isabelle -q HOL Test'';
  3973 
  3974 * system: smart selection of Isabelle process versus Isabelle
  3975 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3976 run both "isabelle" and "Isabelle" even if file names are badly
  3977 damaged (executable inspects the case of the first letter of its own
  3978 name); added separate "isabelle-process" and "isabelle-interface";
  3979 
  3980 * system: refrain from any attempt at filtering input streams; no
  3981 longer support ``8bit'' encoding of old isabelle font, instead proper
  3982 iso-latin characters may now be used; the related isatools
  3983 "symbolinput" and "nonascii" have disappeared as well;
  3984 
  3985 * system: removed old "xterm" interface (the print modes "xterm" and
  3986 "xterm_color" are still available for direct use in a suitable
  3987 terminal);
  3988 
  3989 
  3990 
  3991 New in Isabelle99-2 (February 2001)
  3992 -----------------------------------
  3993 
  3994 *** Overview of INCOMPATIBILITIES ***
  3995 
  3996 * HOL: please note that theories in the Library and elsewhere often use the
  3997 new-style (Isar) format; to refer to their theorems in an ML script you must
  3998 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3999 
  4000 * HOL: inductive package no longer splits induction rule aggressively,
  4001 but only as far as specified by the introductions given; the old
  4002 format may be recovered via ML function complete_split_rule or attribute
  4003 'split_rule (complete)';
  4004 
  4005 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4006 gfp_Tarski to gfp_unfold;
  4007 
  4008 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4009 
  4010 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4011 relation); infix "^^" has been renamed "``"; infix "``" has been
  4012 renamed "`"; "univalent" has been renamed "single_valued";
  4013 
  4014 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4015 operation;
  4016 
  4017 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4018 
  4019 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4020 
  4021 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4022 consequence, it is no longer monotonic wrt. the local goal context
  4023 (which is now passed through the inductive cases);
  4024 
  4025 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4026 \<gg> to \<ggreater>;
  4027 
  4028 
  4029 *** Document preparation ***
  4030 
  4031 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4032 available: are "it" for near math-mode best-style output, "sl" for
  4033 slanted text style, and "tt" for plain type-writer; if no
  4034 \isabellestyle command is given, output is according to slanted
  4035 type-writer);
  4036 
  4037 * support sub/super scripts (for single symbols only), input syntax is
  4038 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4039 
  4040 * some more standard symbols; see Appendix A of the system manual for
  4041 the complete list of symbols defined in isabellesym.sty;
  4042 
  4043 * improved isabelle style files; more abstract symbol implementation
  4044 (should now use \isamath{...} and \isatext{...} in custom symbol
  4045 definitions);
  4046 
  4047 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4048 state; Note that presentation of goal states does not conform to
  4049 actual human-readable proof documents.  Please do not include goal
  4050 states into document output unless you really know what you are doing!
  4051 
  4052 * proper indentation of antiquoted output with proportional LaTeX
  4053 fonts;
  4054 
  4055 * no_document ML operator temporarily disables LaTeX document
  4056 generation;
  4057 
  4058 * isatool unsymbolize tunes sources for plain ASCII communication;
  4059 
  4060 
  4061 *** Isar ***
  4062 
  4063 * Pure: Isar now suffers initial goal statements to contain unbound
  4064 schematic variables (this does not conform to actual readable proof
  4065 documents, due to unpredictable outcome and non-compositional proof
  4066 checking); users who know what they are doing may use schematic goals
  4067 for Prolog-style synthesis of proven results;
  4068 
  4069 * Pure: assumption method (an implicit finishing) now handles actual
  4070 rules as well;
  4071 
  4072 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4073 initial goal, declare "that" only as Pure intro (only for single
  4074 steps); the "that" rule assumption may now be involved in implicit
  4075 finishing, thus ".." becomes a feasible for trivial obtains;
  4076 
  4077 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4078 instance proofs may be performed by "..";
  4079 
  4080 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4081 statements as well;
  4082 
  4083 * Pure: more robust selection of calculational rules;
  4084 
  4085 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4086 rule (as well as the assumption rule);
  4087 
  4088 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4089 lemmas, using the graph browser tool;
  4090 
  4091 * Pure: predict failure of "show" in interactive mode;
  4092 
  4093 * Pure: 'thms_containing' now takes actual terms as arguments;
  4094 
  4095 * HOL: improved method 'induct' --- now handles non-atomic goals
  4096 (potential INCOMPATIBILITY); tuned error handling;
  4097 
  4098 * HOL: cases and induct rules now provide explicit hints about the
  4099 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4100 any remaining facts are inserted into the goal verbatim;
  4101 
  4102 * HOL: local contexts (aka cases) may now contain term bindings as
  4103 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4104 the result to be shown in each case;
  4105 
  4106 * HOL: added 'recdef_tc' command;
  4107 
  4108 * isatool convert assists in eliminating legacy ML scripts;
  4109 
  4110 
  4111 *** HOL ***
  4112 
  4113 * HOL/Library: a collection of generic theories to be used together
  4114 with main HOL; the theory loader path already includes this directory
  4115 by default; the following existing theories have been moved here:
  4116 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4117 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4118 
  4119 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4120 modelling and verification task performed in Isabelle/HOL +
  4121 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4122 
  4123 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4124 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4125 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4126 'domain', this makes the theory consistent with mathematical
  4127 literature;
  4128 
  4129 * HOL basics: added overloaded operations "inverse" and "divide"
  4130 (infix "/"), syntax for generic "abs" operation, generic summation
  4131 operator \<Sum>;
  4132 
  4133 * HOL/typedef: simplified package, provide more useful rules (see also
  4134 HOL/subset.thy);
  4135 
  4136 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4137 now expressed as a proper nested rule (old-style tactic scripts may
  4138 require atomize_strip_tac to cope with non-atomic premises);
  4139 
  4140 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4141 to "split_conv" (old name still available for compatibility);
  4142 
  4143 * HOL: improved concrete syntax for strings (e.g. allows translation
  4144 rules with string literals);
  4145 
  4146 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4147  and Fleuriot's mechanization of analysis, including the transcendental
  4148  functions for the reals;
  4149 
  4150 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4151 
  4152 
  4153 *** CTT ***
  4154 
  4155 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4156 "lam" is displayed as TWO lambda-symbols
  4157 
  4158 * CTT: theory Main now available, containing everything (that is, Bool
  4159 and Arith);
  4160 
  4161 
  4162 *** General ***
  4163 
  4164 * Pure: the Simplifier has been implemented properly as a derived rule
  4165 outside of the actual kernel (at last!); the overall performance
  4166 penalty in practical applications is about 50%, while reliability of
  4167 the Isabelle inference kernel has been greatly improved;
  4168 
  4169 * print modes "brackets" and "no_brackets" control output of nested =>
  4170 (types) and ==> (props); the default behaviour is "brackets";
  4171 
  4172 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4173 as assumptions as well;
  4174 
  4175 * system: support Poly/ML 4.0;
  4176 
  4177 * system: isatool install handles KDE version 1 or 2;
  4178 
  4179 
  4180 
  4181 New in Isabelle99-1 (October 2000)
  4182 ----------------------------------
  4183 
  4184 *** Overview of INCOMPATIBILITIES ***
  4185 
  4186 * HOL: simplification of natural numbers is much changed; to partly
  4187 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4188 issue the following ML commands:
  4189 
  4190   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4191   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4192 
  4193 * HOL: simplification no longer dives into case-expressions; this is
  4194 controlled by "t.weak_case_cong" for each datatype t;
  4195 
  4196 * HOL: nat_less_induct renamed to less_induct;
  4197 
  4198 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4199 fixsome to patch .thy and .ML sources automatically;
  4200 
  4201   select_equality  -> some_equality
  4202   select_eq_Ex     -> some_eq_ex
  4203   selectI2EX       -> someI2_ex
  4204   selectI2         -> someI2
  4205   selectI          -> someI
  4206   select1_equality -> some1_equality
  4207   Eps_sym_eq       -> some_sym_eq_trivial
  4208   Eps_eq           -> some_eq_trivial
  4209 
  4210 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4211 
  4212 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4213 instead);
  4214 
  4215 * HOL: the recursion equations generated by 'recdef' are now called
  4216 f.simps instead of f.rules;
  4217 
  4218 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4219 
  4220 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4221 sometimes be needed;
  4222 
  4223 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4224 
  4225 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4226 
  4227 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4228 product is now "<*>" instead of "Times"; the lexicographic product is
  4229 now "<*lex*>" instead of "**";
  4230 
  4231 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4232 of main HOL, but was unused); better use HOL's datatype package;
  4233 
  4234 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4235 the old syntax may be recovered as follows:
  4236 
  4237   syntax (symbols)
  4238     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4239       (infixl "\\<oplus>" 100)
  4240 
  4241 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4242 
  4243 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4244 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4245 internally;
  4246 
  4247 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4248 changed from A/r to A//r;
  4249 
  4250 * ZF: new treatment of arithmetic (nat & int) may break some old
  4251 proofs;
  4252 
  4253 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4254 rulify -> rule_format, elimify -> elim_format, ...);
  4255 
  4256 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4257 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4258 should have to change intro!! to intro? only); replaced "delrule" by
  4259 "rule del";
  4260 
  4261 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4262 
  4263 * Provers: strengthened force_tac by using new first_best_tac;
  4264 
  4265 * LaTeX document preparation: several changes of isabelle.sty (see
  4266 lib/texinputs);
  4267 
  4268 
  4269 *** Document preparation ***
  4270 
  4271 * formal comments (text blocks etc.) in new-style theories may now
  4272 contain antiquotations of thm/prop/term/typ/text to be presented
  4273 according to latex print mode; concrete syntax is like this:
  4274 @{term[show_types] "f(x) = a + x"};
  4275 
  4276 * isatool mkdir provides easy setup of Isabelle session directories,
  4277 including proper document sources;
  4278 
  4279 * generated LaTeX sources are now deleted after successful run
  4280 (isatool document -c); may retain a copy somewhere else via -D option
  4281 of isatool usedir;
  4282 
  4283 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4284 style files, achieving self-contained LaTeX sources and simplifying
  4285 LaTeX debugging;
  4286 
  4287 * old-style theories now produce (crude) LaTeX output as well;
  4288 
  4289 * browser info session directories are now self-contained (may be put
  4290 on WWW server seperately); improved graphs of nested sessions; removed
  4291 graph for 'all sessions';
  4292 
  4293 * several improvements in isabelle style files; \isabellestyle{it}
  4294 produces fake math mode output; \isamarkupheader is now \section by
  4295 default; see lib/texinputs/isabelle.sty etc.;
  4296 
  4297 
  4298 *** Isar ***
  4299 
  4300 * Isar/Pure: local results and corresponding term bindings are now
  4301 subject to Hindley-Milner polymorphism (similar to ML); this
  4302 accommodates incremental type-inference very nicely;
  4303 
  4304 * Isar/Pure: new derived language element 'obtain' supports
  4305 generalized existence reasoning;
  4306 
  4307 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4308 support accumulation of results, without applying any rules yet;
  4309 useful to collect intermediate results without explicit name
  4310 references, and for use with transitivity rules with more than 2
  4311 premises;
  4312 
  4313 * Isar/Pure: scalable support for case-analysis type proofs: new
  4314 'case' language element refers to local contexts symbolically, as
  4315 produced by certain proof methods; internally, case names are attached
  4316 to theorems as "tags";
  4317 
  4318 * Isar/Pure: theory command 'hide' removes declarations from
  4319 class/type/const name spaces;
  4320 
  4321 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4322 indicate potential overloading;
  4323 
  4324 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4325 
  4326 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4327 "{a,b,c}" instead of {a,b,c};
  4328 
  4329 * Isar/Pure now provides its own version of intro/elim/dest
  4330 attributes; useful for building new logics, but beware of confusion
  4331 with the version in Provers/classical;
  4332 
  4333 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4334 case name 'antecedent';
  4335 
  4336 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4337 to the current context is now done automatically);
  4338 
  4339 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4340 for definining proof methods in ML;
  4341 
  4342 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4343 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4344 most cases, one should have to change intro!! to intro? only);
  4345 replaced "delrule" by "rule del";
  4346 
  4347 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4348 'symmetric' attribute (the latter supercedes [RS sym]);
  4349 
  4350 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4351 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4352 well (including splits);
  4353 
  4354 * Isar/Provers: Simplifier and Classical methods now support all kind
  4355 of modifiers used in the past, including 'cong', 'iff', etc.
  4356 
  4357 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4358 of Simplifier and Classical reasoner);
  4359 
  4360 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4361 now support named cases; major packages (inductive, datatype, primrec,
  4362 recdef) support case names and properly name parameters;
  4363 
  4364 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4365 monotonicity conditions are extracted to be proven at end of
  4366 calculations;
  4367 
  4368 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4369 method anyway;
  4370 
  4371 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4372 split_if split_if_asm; datatype package provides theorems foo.splits =
  4373 foo.split foo.split_asm for each datatype;
  4374 
  4375 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4376 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4377 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4378 use "(cases (simplified))" method in proper proof texts);
  4379 
  4380 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4381 
  4382 * Isar: names of theorems etc. may be natural numbers as well;
  4383 
  4384 * Isar: 'pr' command: optional arguments for goals_limit and
  4385 ProofContext.prems_limit; no longer prints theory contexts, but only
  4386 proof states;
  4387 
  4388 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4389 additional print modes to be specified; e.g. "pr(latex)" will print
  4390 proof state according to the Isabelle LaTeX style;
  4391 
  4392 * Isar: improved support for emulating tactic scripts, including proof
  4393 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4394 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4395 (for HOL datatypes);
  4396 
  4397 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4398 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4399 'proof method scripts' have to be in depth-first order;
  4400 
  4401 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4402 
  4403 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4404 should instead use individual commands for printing items
  4405 (print_commands, print_methods etc.);
  4406 
  4407 * Isar: added 'nothing' --- the empty list of theorems;
  4408 
  4409 
  4410 *** HOL ***
  4411 
  4412 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4413 corresponding virtual machine and a specification of its bytecode
  4414 verifier and a lightweight bytecode verifier, including proofs of
  4415 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4416 Cornelia Pusch (see also the homepage of project Bali at
  4417 http://isabelle.in.tum.de/Bali/);
  4418 
  4419 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4420 Clemens Ballarin;
  4421 
  4422 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4423 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4424 Rasmussen;
  4425 
  4426 * HOL/Lattice: fundamental concepts of lattice theory and order
  4427 structures, including duals, properties of bounds versus algebraic
  4428 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4429 Theorem for complete lattices etc.; may also serve as a demonstration
  4430 for abstract algebraic reasoning using axiomatic type classes, and
  4431 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4432 
  4433 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4434 von Oheimb;
  4435 
  4436 * HOL/IMPP: extension of IMP with local variables and mutually
  4437 recursive procedures, by David von Oheimb;
  4438 
  4439 * HOL/Lambda: converted into new-style theory and document;
  4440 
  4441 * HOL/ex/Multiquote: example of multiple nested quotations and
  4442 anti-quotations -- basically a generalized version of de-Bruijn
  4443 representation; very useful in avoiding lifting of operations;
  4444 
  4445 * HOL/record: added general record equality rule to simpset; fixed
  4446 select-update simplification procedure to handle extended records as
  4447 well; admit "r" as field name;
  4448 
  4449 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4450 other numeric types and also as the identity of groups, rings, etc.;
  4451 
  4452 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4453 Types nat and int belong to this axclass;
  4454 
  4455 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4456    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4457    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4458   two terms #m*u and #n*u are replaced by #(m+n)*u
  4459     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4460   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4461     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4462 
  4463 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4464 powerful prover for predicate logic but knows nothing of clasets; see
  4465 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4466 
  4467 * HOL: new version of "case_tac" subsumes both boolean case split and
  4468 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4469 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4470 
  4471 * HOL: simplification no longer dives into case-expressions: only the
  4472 selector expression is simplified, but not the remaining arms; to
  4473 enable full simplification of case-expressions for datatype t, you may
  4474 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4475 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4476 
  4477 * HOL/recdef: the recursion equations generated by 'recdef' for
  4478 function 'f' are now called f.simps instead of f.rules; if all
  4479 termination conditions are proved automatically, these simplification
  4480 rules are added to the simpset, as in primrec; rules may be named
  4481 individually as well, resulting in a separate list of theorems for
  4482 each equation;
  4483 
  4484 * HOL/While is a new theory that provides a while-combinator. It
  4485 permits the definition of tail-recursive functions without the
  4486 provision of a termination measure. The latter is necessary once the
  4487 invariant proof rule for while is applied.
  4488 
  4489 * HOL: new (overloaded) notation for the set of elements below/above
  4490 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4491 
  4492 * HOL: theorems impI, allI, ballI bound as "strip";
  4493 
  4494 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4495 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4496 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4497 
  4498 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4499 
  4500 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4501 main HOL, but was unused);
  4502 
  4503 * HOL: fewer consts declared as global (e.g. have to refer to
  4504 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4505 
  4506 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4507 in case of overlap with user translations (e.g. judgements over
  4508 tuples); (note that the underlying logical represenation is still
  4509 bogus);
  4510 
  4511 
  4512 *** ZF ***
  4513 
  4514 * ZF: simplification automatically cancels common terms in arithmetic
  4515 expressions over nat and int;
  4516 
  4517 * ZF: new treatment of nat to minimize type-checking: all operators
  4518 coerce their operands to a natural number using the function natify,
  4519 making the algebraic laws unconditional;
  4520 
  4521 * ZF: as above, for int: operators coerce their operands to an integer
  4522 using the function intify;
  4523 
  4524 * ZF: the integer library now contains many of the usual laws for the
  4525 orderings, including $<=, and monotonicity laws for $+ and $*;
  4526 
  4527 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4528 simplification;
  4529 
  4530 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4531 to the simplifier and classical reasoner simultaneously;
  4532 
  4533 
  4534 *** General ***
  4535 
  4536 * Provers: blast_tac now handles actual object-logic rules as
  4537 assumptions; note that auto_tac uses blast_tac internally as well;
  4538 
  4539 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4540 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4541 
  4542 * Provers: delrules now handles destruct rules as well (no longer need
  4543 explicit make_elim);
  4544 
  4545 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4546   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4547 use instead the strong form,
  4548   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4549 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4550 from destruct-rules;
  4551 
  4552 * Provers: Simplifier.easy_setup provides a fast path to basic
  4553 Simplifier setup for new object-logics;
  4554 
  4555 * Pure: AST translation rules no longer require constant head on LHS;
  4556 
  4557 * Pure: improved name spaces: ambiguous output is qualified; support
  4558 for hiding of names;
  4559 
  4560 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4561 XSYMBOL_HOME; no longer need to do manual configuration in most
  4562 situations;
  4563 
  4564 * system: compression of ML heaps images may now be controlled via -c
  4565 option of isabelle and isatool usedir (currently only observed by
  4566 Poly/ML);
  4567 
  4568 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4569 useful for remote X11);
  4570 
  4571 * system: provide TAGS file for Isabelle sources;
  4572 
  4573 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4574 order;
  4575 
  4576 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4577 timing flag supersedes proof_timing and Toplevel.trace;
  4578 
  4579 * ML: new combinators |>> and |>>> for incremental transformations
  4580 with secondary results (e.g. certain theory extensions):
  4581 
  4582 * ML: PureThy.add_defs gets additional argument to indicate potential
  4583 overloading (usually false);
  4584 
  4585 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4586 results;
  4587 
  4588 
  4589 
  4590 New in Isabelle99 (October 1999)
  4591 --------------------------------
  4592 
  4593 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4594 
  4595 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4596 are no longer simplified.  (This allows the simplifier to unfold recursive
  4597 functional programs.)  To restore the old behaviour, declare
  4598 
  4599     Delcongs [if_weak_cong];
  4600 
  4601 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4602 complement;
  4603 
  4604 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4605 
  4606 * HOL/datatype: mutual_induct_tac no longer exists --
  4607   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  4608 
  4609 * HOL/typedef: fixed type inference for representing set; type
  4610 arguments now have to occur explicitly on the rhs as type constraints;
  4611 
  4612 * ZF: The con_defs part of an inductive definition may no longer refer
  4613 to constants declared in the same theory;
  4614 
  4615 * HOL, ZF: the function mk_cases, generated by the inductive
  4616 definition package, has lost an argument.  To simplify its result, it
  4617 uses the default simpset instead of a supplied list of theorems.
  4618 
  4619 * HOL/List: the constructors of type list are now Nil and Cons;
  4620 
  4621 * Simplifier: the type of the infix ML functions
  4622         setSSolver addSSolver setSolver addSolver
  4623 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4624 for packaging solvers. A solver is created via
  4625         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4626 where the string argument is only a comment.
  4627 
  4628 
  4629 *** Proof tools ***
  4630 
  4631 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4632 decision procedure for linear arithmetic. Currently it is used for
  4633 types `nat', `int', and `real' in HOL (see below); it can, should and
  4634 will be instantiated for other types and logics as well.
  4635 
  4636 * The simplifier now accepts rewrite rules with flexible heads, eg
  4637      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4638   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4639   matching.
  4640 
  4641 
  4642 *** General ***
  4643 
  4644 * New Isabelle/Isar subsystem provides an alternative to traditional
  4645 tactical theorem proving; together with the ProofGeneral/isar user
  4646 interface it offers an interactive environment for developing human
  4647 readable proof documents (Isar == Intelligible semi-automated
  4648 reasoning); for further information see isatool doc isar-ref,
  4649 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  4650 
  4651 * improved and simplified presentation of theories: better HTML markup
  4652 (including colors), graph views in several sizes; isatool usedir now
  4653 provides a proper interface for user theories (via -P option); actual
  4654 document preparation based on (PDF)LaTeX is available as well (for
  4655 new-style theories only); see isatool doc system for more information;
  4656 
  4657 * native support for Proof General, both for classic Isabelle and
  4658 Isabelle/Isar;
  4659 
  4660 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  4661 using the graph browser tool;
  4662 
  4663 * Isabelle manuals now also available as PDF;
  4664 
  4665 * theory loader rewritten from scratch (may not be fully
  4666 bug-compatible); old loadpath variable has been replaced by show_path,
  4667 add_path, del_path, reset_path functions; new operations such as
  4668 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  4669 isatool doc ref);
  4670 
  4671 * improved isatool install: option -k creates KDE application icon,
  4672 option -p DIR installs standalone binaries;
  4673 
  4674 * added ML_PLATFORM setting (useful for cross-platform installations);
  4675 more robust handling of platform specific ML images for SML/NJ;
  4676 
  4677 * the settings environment is now statically scoped, i.e. it is never
  4678 created again in sub-processes invoked from isabelle, isatool, or
  4679 Isabelle;
  4680 
  4681 * path element specification '~~' refers to '$ISABELLE_HOME';
  4682 
  4683 * in locales, the "assumes" and "defines" parts may be omitted if
  4684 empty;
  4685 
  4686 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4687 long arrows);
  4688 
  4689 * new print_mode "HTML";
  4690 
  4691 * new flag show_tags controls display of tags of theorems (which are
  4692 basically just comments that may be attached by some tools);
  4693 
  4694 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4695 mode and goal output format:
  4696 
  4697 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4698 244c244
  4699 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4700 ---
  4701 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4702 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4703 181c181
  4704 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4705 ---
  4706 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4707 
  4708 * function bind_thms stores lists of theorems (cf. bind_thm);
  4709 
  4710 * new shorthand tactics ftac, eatac, datac, fatac;
  4711 
  4712 * qed (and friends) now accept "" as result name; in that case the
  4713 theorem is not stored, but proper checks and presentation of the
  4714 result still apply;
  4715 
  4716 * theorem database now also indexes constants "Trueprop", "all",
  4717 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4718 
  4719 
  4720 *** HOL ***
  4721 
  4722 ** HOL arithmetic **
  4723 
  4724 * There are now decision procedures for linear arithmetic over nat and
  4725 int:
  4726 
  4727 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4728 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4729 are treated as atomic; subformulae not involving type `nat' or `int'
  4730 are ignored; quantified subformulae are ignored unless they are
  4731 positive universal or negative existential. The tactic has to be
  4732 invoked by hand and can be a little bit slow. In particular, the
  4733 running time is exponential in the number of occurrences of `min' and
  4734 `max', and `-' on `nat'.
  4735 
  4736 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4737 (negated) (in)equalities among the premises and the conclusion into
  4738 account (i.e. no compound formulae) and does not know about `min' and
  4739 `max', and `-' on `nat'. It is fast and is used automatically by the
  4740 simplifier.
  4741 
  4742 NB: At the moment, these decision procedures do not cope with mixed
  4743 nat/int formulae where the two parts interact, such as `m < n ==>
  4744 int(m) < int(n)'.
  4745 
  4746 * HOL/Numeral provides a generic theory of numerals (encoded
  4747 efficiently as bit strings); setup for types nat/int/real is in place;
  4748 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4749 int, existing theories and proof scripts may require a few additional
  4750 type constraints;
  4751 
  4752 * integer division and remainder can now be performed on constant
  4753 arguments;
  4754 
  4755 * many properties of integer multiplication, division and remainder
  4756 are now available;
  4757 
  4758 * An interface to the Stanford Validity Checker (SVC) is available through the
  4759 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4760 are proved automatically.  SVC must be installed separately, and its results
  4761 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4762 invocation of the underlying oracle).  For SVC see
  4763   http://verify.stanford.edu/SVC
  4764 
  4765 * IsaMakefile: the HOL-Real target now builds an actual image;
  4766 
  4767 
  4768 ** HOL misc **
  4769 
  4770 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4771 (in Isabelle/Isar) -- by Gertrud Bauer;
  4772 
  4773 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4774 analysis for assembly languages with subtypes;
  4775 
  4776 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4777 -- avoids syntactic ambiguities and treats state, transition, and
  4778 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4779 changed syntax and (many) tactics;
  4780 
  4781 * HOL/inductive: Now also handles more general introduction rules such
  4782   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4783   theorems are now maintained within the theory (maintained via the
  4784   "mono" attribute);
  4785 
  4786 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4787   (using function types) such as
  4788 
  4789   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4790 
  4791 * HOL/record: record_simproc (part of the default simpset) takes care
  4792 of selectors applied to updated records; record_split_tac is no longer
  4793 part of the default claset; update_defs may now be removed from the
  4794 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4795 
  4796   claset_ref () := claset() addSWrapper record_split_wrapper;
  4797   Delsimprocs [record_simproc]
  4798 
  4799 * HOL/typedef: fixed type inference for representing set; type
  4800 arguments now have to occur explicitly on the rhs as type constraints;
  4801 
  4802 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4803 names rather than an ML expression;
  4804 
  4805 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4806 supplied later.  Program schemes can be defined, such as
  4807     "While B C s = (if B s then While B C (C s) else s)"
  4808 where the well-founded relation can be chosen after B and C have been given.
  4809 
  4810 * HOL/List: the constructors of type list are now Nil and Cons;
  4811 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4812 course, ML tools referring to List.list.op # etc. have to be adapted;
  4813 
  4814 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4815 disabled by default; run isabelle with option -m HOL to get back to
  4816 the original Gordon/HOL-style output;
  4817 
  4818 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4819 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4820 
  4821 * HOL basic syntax simplified (more orthogonal): all variants of
  4822 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4823 Eps operator is provided as well: "SOME x. P[x]";
  4824 
  4825 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4826 
  4827 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4828 thus available for user theories;
  4829 
  4830 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4831 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4832 time;
  4833 
  4834 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4835 several times and then mp;
  4836 
  4837 
  4838 *** LK ***
  4839 
  4840 * the notation <<...>> is now available as a notation for sequences of
  4841 formulas;
  4842 
  4843 * the simplifier is now installed
  4844 
  4845 * the axiom system has been generalized (thanks to Soren Heilmann)
  4846 
  4847 * the classical reasoner now has a default rule database
  4848 
  4849 
  4850 *** ZF ***
  4851 
  4852 * new primrec section allows primitive recursive functions to be given
  4853 directly (as in HOL) over datatypes and the natural numbers;
  4854 
  4855 * new tactics induct_tac and exhaust_tac for induction (or case
  4856 analysis) over datatypes and the natural numbers;
  4857 
  4858 * the datatype declaration of type T now defines the recursor T_rec;
  4859 
  4860 * simplification automatically does freeness reasoning for datatype
  4861 constructors;
  4862 
  4863 * automatic type-inference, with AddTCs command to insert new
  4864 type-checking rules;
  4865 
  4866 * datatype introduction rules are now added as Safe Introduction rules
  4867 to the claset;
  4868 
  4869 * the syntax "if P then x else y" is now available in addition to
  4870 if(P,x,y);
  4871 
  4872 
  4873 *** Internal programming interfaces ***
  4874 
  4875 * tuned simplifier trace output; new flag debug_simp;
  4876 
  4877 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4878 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4879 
  4880 * AxClass.axclass_tac lost the theory argument;
  4881 
  4882 * tuned current_goals_markers semantics: begin / end goal avoids
  4883 printing empty lines;
  4884 
  4885 * removed prs and prs_fn hook, which was broken because it did not
  4886 include \n in its semantics, forcing writeln to add one
  4887 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4888 string -> unit if you really want to output text without newline;
  4889 
  4890 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4891 plain output, interface builders may have to enable 'isabelle_font'
  4892 mode to get Isabelle font glyphs as before;
  4893 
  4894 * refined token_translation interface; INCOMPATIBILITY: output length
  4895 now of type real instead of int;
  4896 
  4897 * theory loader actions may be traced via new ThyInfo.add_hook
  4898 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4899 your own database of information attached to *whole* theories -- as
  4900 opposed to intra-theory data slots offered via TheoryDataFun;
  4901 
  4902 * proper handling of dangling sort hypotheses (at last!);
  4903 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4904 extra sort hypotheses that can be witnessed from the type signature;
  4905 the force_strip_shyps flag is gone, any remaining shyps are simply
  4906 left in the theorem (with a warning issued by strip_shyps_warning);
  4907 
  4908 
  4909 
  4910 New in Isabelle98-1 (October 1998)
  4911 ----------------------------------
  4912 
  4913 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4914 
  4915 * several changes of automated proof tools;
  4916 
  4917 * HOL: major changes to the inductive and datatype packages, including
  4918 some minor incompatibilities of theory syntax;
  4919 
  4920 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4921 called `inj_on';
  4922 
  4923 * HOL: removed duplicate thms in Arith:
  4924   less_imp_add_less  should be replaced by  trans_less_add1
  4925   le_imp_add_le      should be replaced by  trans_le_add1
  4926 
  4927 * HOL: unary minus is now overloaded (new type constraints may be
  4928 required);
  4929 
  4930 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4931 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4932 now taken as an integer constant.
  4933 
  4934 * Pure: ML function 'theory_of' renamed to 'theory';
  4935 
  4936 
  4937 *** Proof tools ***
  4938 
  4939 * Simplifier:
  4940   1. Asm_full_simp_tac is now more aggressive.
  4941      1. It will sometimes reorient premises if that increases their power to
  4942         simplify.
  4943      2. It does no longer proceed strictly from left to right but may also
  4944         rotate premises to achieve further simplification.
  4945      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4946      old Asm_full_simp_tac in that it does not rotate premises.
  4947   2. The simplifier now knows a little bit about nat-arithmetic.
  4948 
  4949 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4950 allows for selected deletion of wrappers, by introduction of names for
  4951 wrapper functionals.  This implies that addbefore, addSbefore,
  4952 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4953 and that adding two tactics with the same name overwrites the first
  4954 one (emitting a warning).
  4955   type wrapper = (int -> tactic) -> (int -> tactic)
  4956   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4957   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4958   delWrapper, delSWrapper: claset *  string            -> claset
  4959   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4960 
  4961 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4962 semantics; addbefore now affects only the unsafe part of step_tac
  4963 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4964 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4965 by Force_tac;
  4966 
  4967 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4968 compWrapper; added safe wrapper (and access functions for it);
  4969 
  4970 * HOL/split_all_tac is now much faster and fails if there is nothing
  4971 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4972 and the names of the automatically generated variables have changed.
  4973 split_all_tac has moved within claset() from unsafe wrappers to safe
  4974 wrappers, which means that !!-bound variables are split much more
  4975 aggressively, and safe_tac and clarify_tac now split such variables.
  4976 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4977 Note: the same holds for record_split_tac, which does the job of
  4978 split_all_tac for record fields.
  4979 
  4980 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4981 permanently to the default simpset using Addsplits just like
  4982 Addsimps. They can be removed via Delsplits just like
  4983 Delsimps. Lower-case versions are also available.
  4984 
  4985 * HOL/Simplifier: The rule split_if is now part of the default
  4986 simpset. This means that the simplifier will eliminate all occurrences
  4987 of if-then-else in the conclusion of a goal. To prevent this, you can
  4988 either remove split_if completely from the default simpset by
  4989 `Delsplits [split_if]' or remove it in a specific call of the
  4990 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4991 other case splitting rules to/from the default simpset: every datatype
  4992 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4993 t is the name of the datatype).
  4994 
  4995 * Classical reasoner / Simplifier combination: new force_tac (and
  4996 derivatives Force_tac, force) combines rewriting and classical
  4997 reasoning (and whatever other tools) similarly to auto_tac, but is
  4998 aimed to solve the given subgoal completely.
  4999 
  5000 
  5001 *** General ***
  5002 
  5003 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5004 and `goalw': the theory is no longer needed as an explicit argument -
  5005 the current theory context is used; assumptions are no longer returned
  5006 at the ML-level unless one of them starts with ==> or !!; it is
  5007 recommended to convert to these new commands using isatool fixgoal
  5008 (backup your sources first!);
  5009 
  5010 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5011 the current theory context, and 'theory' to lookup stored theories;
  5012 
  5013 * new theory section 'locale' for declaring constants, assumptions and
  5014 definitions that have local scope;
  5015 
  5016 * new theory section 'nonterminals' for purely syntactic types;
  5017 
  5018 * new theory section 'setup' for generic ML setup functions
  5019 (e.g. package initialization);
  5020 
  5021 * the distribution now includes Isabelle icons: see
  5022 lib/logo/isabelle-{small,tiny}.xpm;
  5023 
  5024 * isatool install - install binaries with absolute references to
  5025 ISABELLE_HOME/bin;
  5026 
  5027 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5028 
  5029 * print mode 'emacs' reserved for Isamode;
  5030 
  5031 * support multiple print (ast) translations per constant name;
  5032 
  5033 * theorems involving oracles are now printed with a suffixed [!];
  5034 
  5035 
  5036 *** HOL ***
  5037 
  5038 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5039 
  5040 * HOL/inductive package reorganized and improved: now supports mutual
  5041 definitions such as
  5042 
  5043   inductive EVEN ODD
  5044     intrs
  5045       null "0 : EVEN"
  5046       oddI "n : EVEN ==> Suc n : ODD"
  5047       evenI "n : ODD ==> Suc n : EVEN"
  5048 
  5049 new theorem list "elims" contains an elimination rule for each of the
  5050 recursive sets; inductive definitions now handle disjunctive premises
  5051 correctly (also ZF);
  5052 
  5053 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5054 "mutual_induct" no longer exists - the induction rule is always
  5055 contained in "induct";
  5056 
  5057 
  5058 * HOL/datatype package re-implemented and greatly improved: now
  5059 supports mutually recursive datatypes such as
  5060 
  5061   datatype
  5062     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5063             | SUM ('a aexp) ('a aexp)
  5064             | DIFF ('a aexp) ('a aexp)
  5065             | NUM 'a
  5066   and
  5067     'a bexp = LESS ('a aexp) ('a aexp)
  5068             | AND ('a bexp) ('a bexp)
  5069             | OR ('a bexp) ('a bexp)
  5070 
  5071 as well as indirectly recursive datatypes such as
  5072 
  5073   datatype
  5074     ('a, 'b) term = Var 'a
  5075                   | App 'b ((('a, 'b) term) list)
  5076 
  5077 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5078 induction on mutually / indirectly recursive datatypes.
  5079 
  5080 Primrec equations are now stored in theory and can be accessed via
  5081 <function_name>.simps.
  5082 
  5083 INCOMPATIBILITIES:
  5084 
  5085   - Theories using datatypes must now have theory Datatype as an
  5086     ancestor.
  5087   - The specific <typename>.induct_tac no longer exists - use the
  5088     generic induct_tac instead.
  5089   - natE has been renamed to nat.exhaust - use exhaust_tac
  5090     instead of res_inst_tac ... natE. Note that the variable
  5091     names in nat.exhaust differ from the names in natE, this
  5092     may cause some "fragile" proofs to fail.
  5093   - The theorems split_<typename>_case and split_<typename>_case_asm
  5094     have been renamed to <typename>.split and <typename>.split_asm.
  5095   - Since default sorts of type variables are now handled correctly,
  5096     some datatype definitions may have to be annotated with explicit
  5097     sort constraints.
  5098   - Primrec definitions no longer require function name and type
  5099     of recursive argument.
  5100 
  5101 Consider using isatool fixdatatype to adapt your theories and proof
  5102 scripts to the new package (backup your sources first!).
  5103 
  5104 
  5105 * HOL/record package: considerably improved implementation; now
  5106 includes concrete syntax for record types, terms, updates; theorems
  5107 for surjective pairing and splitting !!-bound record variables; proof
  5108 support is as follows:
  5109 
  5110   1) standard conversions (selectors or updates applied to record
  5111 constructor terms) are part of the standard simpset;
  5112 
  5113   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5114 made part of standard simpset and claset via addIffs;
  5115 
  5116   3) a tactic for record field splitting (record_split_tac) is part of
  5117 the standard claset (addSWrapper);
  5118 
  5119 To get a better idea about these rules you may retrieve them via
  5120 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5121 the name of your record type.
  5122 
  5123 The split tactic 3) conceptually simplifies by the following rule:
  5124 
  5125   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5126 
  5127 Thus any record variable that is bound by meta-all will automatically
  5128 blow up into some record constructor term, consequently the
  5129 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5130 solve record problems automatically.
  5131 
  5132 
  5133 * reorganized the main HOL image: HOL/Integ and String loaded by
  5134 default; theory Main includes everything;
  5135 
  5136 * automatic simplification of integer sums and comparisons, using cancellation;
  5137 
  5138 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5139 
  5140 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5141 
  5142 * many new identities for unions, intersections, set difference, etc.;
  5143 
  5144 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5145 called split_if, split_split, split_sum_case and split_nat_case (to go
  5146 with add/delsplits);
  5147 
  5148 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5149 (?x::unit) = (); this is made part of the default simpset, which COULD
  5150 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5151 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5152 unit_abs_eta_conv is added in order to counter the effect of
  5153 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5154 %u.f();
  5155 
  5156 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5157 makes more sense);
  5158 
  5159 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5160   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5161   disjointness reasoning but breaking a few old proofs.
  5162 
  5163 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5164 to 'converse' from 'inverse' (for compatibility with ZF and some
  5165 literature);
  5166 
  5167 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5168 the well-founded relation;
  5169 
  5170 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5171     Compl A.  The "Compl" syntax remains available as input syntax for this
  5172     release ONLY.
  5173 
  5174 * HOL/Update: new theory of function updates:
  5175     f(a:=b) == %x. if x=a then b else f x
  5176 may also be iterated as in f(a:=b,c:=d,...);
  5177 
  5178 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5179 
  5180 * HOL/List:
  5181   - new function list_update written xs[i:=v] that updates the i-th
  5182     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5183   - new function `upt' written [i..j(] which generates the list
  5184     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5185     bound write [i..j], which is a shorthand for [i..j+1(].
  5186   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5187 
  5188 * HOL/Arith:
  5189   - removed 'pred' (predecessor) function;
  5190   - generalized some theorems about n-1;
  5191   - many new laws about "div" and "mod";
  5192   - new laws about greatest common divisors (see theory ex/Primes);
  5193 
  5194 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5195 instead of "inverse";
  5196 
  5197 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5198   of the multiset ordering;
  5199 
  5200 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5201   (not included by default);
  5202 
  5203 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5204 
  5205 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5206   programs, i.e. different program variables may have different types.
  5207 
  5208 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5209   [previously, this check worked only if the rewrite rule was unconditional]
  5210   Now rew can involve either definitions or equalities (either == or =).
  5211 
  5212 
  5213 *** ZF ***
  5214 
  5215 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5216   only the theorems proved on ZF.ML;
  5217 
  5218 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5219   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5220   disjointness reasoning but breaking a few old proofs.
  5221 
  5222 * ZF/Update: new theory of function updates
  5223     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5224   may also be iterated as in f(a:=b,c:=d,...);
  5225 
  5226 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5227 
  5228 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5229   [previously, this check worked only if the rewrite rule was unconditional]
  5230   Now rew can involve either definitions or equalities (either == or =).
  5231 
  5232 * case_tac provided for compatibility with HOL
  5233     (like the old excluded_middle_tac, but with subgoals swapped)
  5234 
  5235 
  5236 *** Internal programming interfaces ***
  5237 
  5238 * Pure: several new basic modules made available for general use, see
  5239 also src/Pure/README;
  5240 
  5241 * improved the theory data mechanism to support encapsulation (data
  5242 kind name replaced by private Object.kind, acting as authorization
  5243 key); new type-safe user interface via functor TheoryDataFun; generic
  5244 print_data function becomes basically useless;
  5245 
  5246 * removed global_names compatibility flag -- all theory declarations
  5247 are qualified by default;
  5248 
  5249 * module Pure/Syntax now offers quote / antiquote translation
  5250 functions (useful for Hoare logic etc. with implicit dependencies);
  5251 see HOL/ex/Antiquote for an example use;
  5252 
  5253 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5254 cterm -> thm;
  5255 
  5256 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5257 subgoal;
  5258 
  5259 * Display.print_goals function moved to Locale.print_goals;
  5260 
  5261 * standard print function for goals supports current_goals_markers
  5262 variable for marking begin of proof, end of proof, start of goal; the
  5263 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5264 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5265 for example;
  5266 
  5267 
  5268 
  5269 New in Isabelle98 (January 1998)
  5270 --------------------------------
  5271 
  5272 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5273 
  5274 * changed lexical syntax of terms / types: dots made part of long
  5275 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5276 
  5277 * simpset (and claset) reference variable replaced by functions
  5278 simpset / simpset_ref;
  5279 
  5280 * no longer supports theory aliases (via merge) and non-trivial
  5281 implicit merge of thms' signatures;
  5282 
  5283 * most internal names of constants changed due to qualified names;
  5284 
  5285 * changed Pure/Sequence interface (see Pure/seq.ML);
  5286 
  5287 
  5288 *** General Changes ***
  5289 
  5290 * hierachically structured name spaces (for consts, types, axms, thms
  5291 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5292 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5293 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5294 long_names for fully qualified output names; NOTE: ML programs
  5295 (special tactics, packages etc.) referring to internal names may have
  5296 to be adapted to cope with fully qualified names; in case of severe
  5297 backward campatibility problems try setting 'global_names' at compile
  5298 time to have enrything declared within a flat name space; one may also
  5299 fine tune name declarations in theories via the 'global' and 'local'
  5300 section;
  5301 
  5302 * reimplemented the implicit simpset and claset using the new anytype
  5303 data filed in signatures; references simpset:simpset ref etc. are
  5304 replaced by functions simpset:unit->simpset and
  5305 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5306 to patch your ML files accordingly;
  5307 
  5308 * HTML output now includes theory graph data for display with Java
  5309 applet or isatool browser; data generated automatically via isatool
  5310 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5311 
  5312 * defs may now be conditional; improved rewrite_goals_tac to handle
  5313 conditional equations;
  5314 
  5315 * defs now admits additional type arguments, using TYPE('a) syntax;
  5316 
  5317 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5318 creates a new theory node; implicit merge of thms' signatures is
  5319 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5320 transfer:theory->thm->thm in (rare) cases;
  5321 
  5322 * improved handling of draft signatures / theories; draft thms (and
  5323 ctyps, cterms) are automatically promoted to real ones;
  5324 
  5325 * slightly changed interfaces for oracles: admit many per theory, named
  5326 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5327 
  5328 * print_goals: optional output of const types (set show_consts and
  5329 show_types);
  5330 
  5331 * improved output of warnings (###) and errors (***);
  5332 
  5333 * subgoal_tac displays a warning if the new subgoal has type variables;
  5334 
  5335 * removed old README and Makefiles;
  5336 
  5337 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5338 
  5339 * removed obsolete init_pps and init_database;
  5340 
  5341 * deleted the obsolete tactical STATE, which was declared by
  5342     fun STATE tacfun st = tacfun st st;
  5343 
  5344 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5345 (which abbreviates $HOME);
  5346 
  5347 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5348 use isatool fixseq to adapt your ML programs (this works for fully
  5349 qualified references to the Sequence structure only!);
  5350 
  5351 * use_thy no longer requires writable current directory; it always
  5352 reloads .ML *and* .thy file, if either one is out of date;
  5353 
  5354 
  5355 *** Classical Reasoner ***
  5356 
  5357 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5358 tactics that use classical reasoning to simplify a subgoal without
  5359 splitting it into several subgoals;
  5360 
  5361 * Safe_tac: like safe_tac but uses the default claset;
  5362 
  5363 
  5364 *** Simplifier ***
  5365 
  5366 * added simplification meta rules:
  5367     (asm_)(full_)simplify: simpset -> thm -> thm;
  5368 
  5369 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5370 logics (again);
  5371 
  5372 * added prems argument to simplification procedures;
  5373 
  5374 * HOL, FOL, ZF: added infix function `addsplits':
  5375   instead of `<simpset> setloop (split_tac <thms>)'
  5376   you can simply write `<simpset> addsplits <thms>'
  5377 
  5378 
  5379 *** Syntax ***
  5380 
  5381 * TYPE('a) syntax for type reflection terms;
  5382 
  5383 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5384 
  5385 * pretty printer: changed order of mixfix annotation preference (again!);
  5386 
  5387 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5388 
  5389 
  5390 *** HOL ***
  5391 
  5392 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5393   with `addloop' of the simplifier to faciliate case splitting in premises.
  5394 
  5395 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5396 
  5397 * HOL/Auth: new protocol proofs including some for the Internet
  5398   protocol TLS;
  5399 
  5400 * HOL/Map: new theory of `maps' a la VDM;
  5401 
  5402 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5403 cancelling out common nat summands from =, <, <= (in)equalities, or
  5404 differences; simplification procedures nat_cancel_factor for
  5405 cancelling common factor from =, <, <= (in)equalities over natural
  5406 sums; nat_cancel contains both kinds of procedures, it is installed by
  5407 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5408 
  5409 * HOL/simplifier: terms of the form
  5410   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5411   are rewritten to
  5412   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5413   and those of the form
  5414   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5415   are rewritten to
  5416   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5417 
  5418 * HOL/datatype
  5419   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5420 
  5421   P(t_case f1 ... fn x) =
  5422      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5423         ...
  5424        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5425      )
  5426 
  5427   and a theorem `split_t_case_asm' of the form
  5428 
  5429   P(t_case f1 ... fn x) =
  5430     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5431         ...
  5432        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5433      )
  5434   which can be added to a simpset via `addsplits'. The existing theorems
  5435   expand_list_case and expand_option_case have been renamed to
  5436   split_list_case and split_option_case.
  5437 
  5438 * HOL/Arithmetic:
  5439   - `pred n' is automatically converted to `n-1'.
  5440     Users are strongly encouraged not to use `pred' any longer,
  5441     because it will disappear altogether at some point.
  5442   - Users are strongly encouraged to write "0 < n" rather than
  5443     "n ~= 0". Theorems and proof tools have been modified towards this
  5444     `standard'.
  5445 
  5446 * HOL/Lists:
  5447   the function "set_of_list" has been renamed "set" (and its theorems too);
  5448   the function "nth" now takes its arguments in the reverse order and
  5449   has acquired the infix notation "!" as in "xs!n".
  5450 
  5451 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5452 
  5453 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5454   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5455 
  5456 * HOL/record: extensible records with schematic structural subtyping
  5457 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5458 still lacks various theorems and concrete record syntax;
  5459 
  5460 
  5461 *** HOLCF ***
  5462 
  5463 * removed "axioms" and "generated by" sections;
  5464 
  5465 * replaced "ops" section by extended "consts" section, which is capable of
  5466   handling the continuous function space "->" directly;
  5467 
  5468 * domain package:
  5469   . proves theorems immediately and stores them in the theory,
  5470   . creates hierachical name space,
  5471   . now uses normal mixfix annotations (instead of cinfix...),
  5472   . minor changes to some names and values (for consistency),
  5473   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5474   . separator between mutual domain defs: changed "," to "and",
  5475   . improved handling of sort constraints;  now they have to
  5476     appear on the left-hand side of the equations only;
  5477 
  5478 * fixed LAM <x,y,zs>.b syntax;
  5479 
  5480 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5481 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5482 
  5483 
  5484 *** FOL and ZF ***
  5485 
  5486 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5487   with `addloop' of the simplifier to faciliate case splitting in premises.
  5488 
  5489 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5490 in HOL, they strip ALL and --> from proved theorems;
  5491 
  5492 
  5493 
  5494 New in Isabelle94-8 (May 1997)
  5495 ------------------------------
  5496 
  5497 *** General Changes ***
  5498 
  5499 * new utilities to build / run / maintain Isabelle etc. (in parts
  5500 still somewhat experimental); old Makefiles etc. still functional;
  5501 
  5502 * new 'Isabelle System Manual';
  5503 
  5504 * INSTALL text, together with ./configure and ./build scripts;
  5505 
  5506 * reimplemented type inference for greater efficiency, better error
  5507 messages and clean internal interface;
  5508 
  5509 * prlim command for dealing with lots of subgoals (an easier way of
  5510 setting goals_limit);
  5511 
  5512 
  5513 *** Syntax ***
  5514 
  5515 * supports alternative (named) syntax tables (parser and pretty
  5516 printer); internal interface is provided by add_modesyntax(_i);
  5517 
  5518 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5519 be used in conjunction with the Isabelle symbol font; uses the
  5520 "symbols" syntax table;
  5521 
  5522 * added token_translation interface (may translate name tokens in
  5523 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5524 the current print_mode); IMPORTANT: user print translation functions
  5525 are responsible for marking newly introduced bounds
  5526 (Syntax.mark_boundT);
  5527 
  5528 * token translations for modes "xterm" and "xterm_color" that display
  5529 names in bold, underline etc. or colors (which requires a color
  5530 version of xterm);
  5531 
  5532 * infixes may now be declared with names independent of their syntax;
  5533 
  5534 * added typed_print_translation (like print_translation, but may
  5535 access type of constant);
  5536 
  5537 
  5538 *** Classical Reasoner ***
  5539 
  5540 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5541 some limitations.  Blast_tac...
  5542   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5543   + ignores elimination rules that don't have the correct format
  5544         (the conclusion MUST be a formula variable)
  5545   + ignores types, which can make HOL proofs fail
  5546   + rules must not require higher-order unification, e.g. apply_type in ZF
  5547     [message "Function Var's argument not a bound variable" relates to this]
  5548   + its proof strategy is more general but can actually be slower
  5549 
  5550 * substitution with equality assumptions no longer permutes other
  5551 assumptions;
  5552 
  5553 * minor changes in semantics of addafter (now called addaltern); renamed
  5554 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5555 (and access functions for it);
  5556 
  5557 * improved combination of classical reasoner and simplifier:
  5558   + functions for handling clasimpsets
  5559   + improvement of addss: now the simplifier is called _after_ the
  5560     safe steps.
  5561   + safe variant of addss called addSss: uses safe simplifications
  5562     _during_ the safe steps. It is more complete as it allows multiple
  5563     instantiations of unknowns (e.g. with slow_tac).
  5564 
  5565 *** Simplifier ***
  5566 
  5567 * added interface for simplification procedures (functions that
  5568 produce *proven* rewrite rules on the fly, depending on current
  5569 redex);
  5570 
  5571 * ordering on terms as parameter (used for ordered rewriting);
  5572 
  5573 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5574 
  5575 * the solver is now split into a safe and an unsafe part.
  5576 This should be invisible for the normal user, except that the
  5577 functions setsolver and addsolver have been renamed to setSolver and
  5578 addSolver; added safe_asm_full_simp_tac;
  5579 
  5580 
  5581 *** HOL ***
  5582 
  5583 * a generic induction tactic `induct_tac' which works for all datatypes and
  5584 also for type `nat';
  5585 
  5586 * a generic case distinction tactic `exhaust_tac' which works for all
  5587 datatypes and also for type `nat';
  5588 
  5589 * each datatype comes with a function `size';
  5590 
  5591 * patterns in case expressions allow tuple patterns as arguments to
  5592 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5593 
  5594 * primrec now also works with type nat;
  5595 
  5596 * recdef: a new declaration form, allows general recursive functions to be
  5597 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5598 
  5599 * the constant for negation has been renamed from "not" to "Not" to
  5600 harmonize with FOL, ZF, LK, etc.;
  5601 
  5602 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5603 infinite lists;
  5604 
  5605 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5606 
  5607 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  5608 problems in commutative rings, using axiomatic type classes for + and *;
  5609 
  5610 * more examples in HOL/MiniML and HOL/Auth;
  5611 
  5612 * more default rewrite rules for quantifiers, union/intersection;
  5613 
  5614 * a new constant `arbitrary == @x.False';
  5615 
  5616 * HOLCF/IOA replaces old HOL/IOA;
  5617 
  5618 * HOLCF changes: derived all rules and arities
  5619   + axiomatic type classes instead of classes
  5620   + typedef instead of faking type definitions
  5621   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5622   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5623   + eliminated the types void, one, tr
  5624   + use unit lift and bool lift (with translations) instead of one and tr
  5625   + eliminated blift from Lift3.thy (use Def instead of blift)
  5626   all eliminated rules are derived as theorems --> no visible changes ;
  5627 
  5628 
  5629 *** ZF ***
  5630 
  5631 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5632 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5633 as ZF_cs addSIs [equalityI];
  5634 
  5635 
  5636 
  5637 New in Isabelle94-7 (November 96)
  5638 ---------------------------------
  5639 
  5640 * allowing negative levels (as offsets) in prlev and choplev;
  5641 
  5642 * super-linear speedup for large simplifications;
  5643 
  5644 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  5645 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  5646 FAIL); can suppress it using the command Delsimps (ex_simps @
  5647 all_simps); De Morgan laws are also now included, by default;
  5648 
  5649 * improved printing of ==>  :  ~:
  5650 
  5651 * new object-logic "Sequents" adds linear logic, while replacing LK
  5652 and Modal (thanks to Sara Kalvala);
  5653 
  5654 * HOL/Auth: correctness proofs for authentication protocols;
  5655 
  5656 * HOL: new auto_tac combines rewriting and classical reasoning (many
  5657 examples on HOL/Auth);
  5658 
  5659 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  5660 the rewriter and classical reasoner simultaneously;
  5661 
  5662 * function uresult no longer returns theorems in "standard" format;
  5663 regain previous version by: val uresult = standard o uresult;
  5664 
  5665 
  5666 
  5667 New in Isabelle94-6
  5668 -------------------
  5669 
  5670 * oracles -- these establish an interface between Isabelle and trusted
  5671 external reasoners, which may deliver results as theorems;
  5672 
  5673 * proof objects (in particular record all uses of oracles);
  5674 
  5675 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  5676 
  5677 * "constdefs" section in theory files;
  5678 
  5679 * "primrec" section (HOL) no longer requires names;
  5680 
  5681 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  5682 
  5683 
  5684 
  5685 New in Isabelle94-5
  5686 -------------------
  5687 
  5688 * reduced space requirements;
  5689 
  5690 * automatic HTML generation from theories;
  5691 
  5692 * theory files no longer require "..." (quotes) around most types;
  5693 
  5694 * new examples, including two proofs of the Church-Rosser theorem;
  5695 
  5696 * non-curried (1994) version of HOL is no longer distributed;
  5697 
  5698 
  5699 
  5700 New in Isabelle94-4
  5701 -------------------
  5702 
  5703 * greatly reduced space requirements;
  5704 
  5705 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5706 
  5707 * searchable theorem database (see the section "Retrieving theorems" on
  5708 page 8 of the Reference Manual);
  5709 
  5710 * new examples, including Grabczewski's monumental case study of the
  5711 Axiom of Choice;
  5712 
  5713 * The previous version of HOL renamed to Old_HOL;
  5714 
  5715 * The new version of HOL (previously called CHOL) uses a curried syntax
  5716 for functions.  Application looks like f a b instead of f(a,b);
  5717 
  5718 * Mutually recursive inductive definitions finally work in HOL;
  5719 
  5720 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5721 translates to the operator "split";
  5722 
  5723 
  5724 
  5725 New in Isabelle94-3
  5726 -------------------
  5727 
  5728 * new infix operator, addss, allowing the classical reasoner to
  5729 perform simplification at each step of its search.  Example:
  5730         fast_tac (cs addss ss)
  5731 
  5732 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5733 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5734 look like (a,b) instead of <a,b>;
  5735 
  5736 * PLEASE NOTE: CHOL will eventually replace HOL!
  5737 
  5738 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5739 It translates to the operator "split".  A new theory of integers is available;
  5740 
  5741 * In ZF, integer numerals now denote two's-complement binary integers.
  5742 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5743 
  5744 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5745 of the Axiom of Choice;
  5746 
  5747 
  5748 
  5749 New in Isabelle94-2
  5750 -------------------
  5751 
  5752 * Significantly faster resolution;
  5753 
  5754 * the different sections in a .thy file can now be mixed and repeated
  5755 freely;
  5756 
  5757 * Database of theorems for FOL, HOL and ZF.  New
  5758 commands including qed, qed_goal and bind_thm store theorems in the database.
  5759 
  5760 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5761 a given theory (thms_of), or find out what theory a theorem was proved in
  5762 (theory_of_thm);
  5763 
  5764 * Bugs fixed in the inductive definition and datatype packages;
  5765 
  5766 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5767 and HOL_dup_cs obsolete;
  5768 
  5769 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5770 have been removed;
  5771 
  5772 * Simpler definition of function space in ZF;
  5773 
  5774 * new results about cardinal and ordinal arithmetic in ZF;
  5775 
  5776 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5777 types;
  5778 
  5779 :mode=text:wrap=hard:maxLineLen=72:
  5780 
  5781 
  5782 $Id$