NEWS
author ballarin
Tue Sep 02 17:31:20 2008 +0200 (2008-09-02)
changeset 28085 914183e229e9
parent 28067 4b6783d3f0d9
child 28088 723735f2d73a
permissions -rw-r--r--
Interpretation commands no longer accept interpretation attributes.
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Generalized Isar history, with support for linear undo, direct state
    10 addressing etc.
    11 
    12 * Recovered hiding of consts, which was accidentally broken in
    13 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
    14 makes c inaccessible; consider using ``hide (open) const c'' instead.
    15 
    16 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
    17 interface instead.
    18 
    19 
    20 *** Pure ***
    21 
    22 * Global versions of theorems stemming from classes do not carry
    23 a parameter prefix any longer.  INCOMPATIBILITY.
    24 
    25 * Dropped "locale (open)".  INCOMPATBILITY.
    26 
    27 * Interpretation commands no longer attempt to simplify goal.
    28 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
    29 methods intro_locales and unfold_locales to clarify.
    30 
    31 * Interpretation commands no longer accept interpretation attributes.
    32 INCOMPATBILITY.
    33 
    34 * Command 'instance': attached definitions no longer accepted.
    35 INCOMPATIBILITY, use proper 'instantiation' target.
    36 
    37 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
    38 
    39 
    40 *** Document preparation ***
    41 
    42 * Antiquotation @{lemma} now imitates a regular terminal proof,
    43 demanding keyword 'by' and supporting the full method expression
    44 syntax just like the Isar command 'by'.
    45 
    46 
    47 *** HOL ***
    48 
    49 * HOL/Orderings: class "wellorder" moved here, with explicit induction rule
    50 "less_induct" as assumption.  For instantiation of "wellorder" by means
    51 of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.
    52 
    53 * HOL/Orderings: added class "preorder" as superclass of "order".
    54 INCOMPATIBILITY: Instantiation proofs for order, linorder
    55 etc. slightly changed.  Some theorems named order_class.* now named
    56 preorder_class.*.
    57 
    58 * HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
    59 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
    60 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
    61 of lemmas from Divides has been generalized from nat to class
    62 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
    63 renames resulting from duplicate elimination:
    64 
    65     dvd_def_mod ~>          dvd_eq_mod_eq_0
    66     zero_dvd_iff ~>         dvd_0_left_iff
    67     DIVISION_BY_ZERO_DIV ~> div_by_0
    68     DIVISION_BY_ZERO_MOD ~> mod_by_0
    69     mult_div ~>             div_mult_self2_is_id
    70     mult_mod ~>             mod_mult_self2_is_0
    71 
    72 * HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
    73 zlcm (for int); carried together from various gcd/lcm developements in
    74 the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
    75 corresponding theorems renamed accordingly.  INCOMPATIBILY.  To
    76 recover tupled syntax, use syntax declarations like:
    77 
    78     hide (open) const gcd
    79     abbreviation gcd where
    80       "gcd == (%(a, b). GCD.gcd a b)"
    81     notation (output)
    82       GCD.gcd ("gcd '(_, _')")
    83 
    84 (analogously for lcm, zgcd, zlcm).
    85 
    86 * HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
    87 
    88 * New ML antiquotation @{code}: takes constant as argument, generates
    89 corresponding code in background and inserts name of the corresponding
    90 resulting ML value/function/datatype constructor binding in place.
    91 All occurrences of @{code} with a single ML block are generated
    92 simultaneously.  Provides a generic and safe interface for
    93 instrumentalizing code generation.  See HOL/ex/Code_Antiq for a toy
    94 example, or HOL/Complex/ex/ReflectedFerrack for a more ambitious
    95 application.  In future you ought refrain from ad-hoc compiling
    96 generated SML code on the ML toplevel.  Note that (for technical
    97 reasons) @{code} cannot refer to constants for which user-defined
    98 serializations are set.  Refer to the corresponding ML counterpart
    99 directly in that cases.
   100 
   101 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   102 Complex_Main.thy remain as they are.
   103 
   104 * New image HOL-Plain provides a minimal HOL with the most important
   105 tools available (inductive, datatype, primrec, ...).  By convention
   106 the corresponding theory Plain should be ancestor of every further
   107 (library) theory.  Some library theories now have ancestor Plain
   108 (instead of Main), thus theory Main occasionally has to be imported
   109 explicitly.
   110 
   111 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   112 as the structured Isar versions "cases" and "induct", cf. the
   113 corresponding "cases" and "induct" attributes.  Mutual induction rules
   114 are now presented as a list of individual projections
   115 (e.g. foo_bar.inducts for types foo and bar); the old format with
   116 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   117 rare situations a different rule is selected --- notably nested tuple
   118 elimination instead of former prod.exhaust: use explicit (case_tac t
   119 rule: prod.exhaust) here.
   120 
   121 * Attributes "cases", "induct", "coinduct" support "del" option.
   122 
   123 * Removed fact "case_split_thm", which duplicates "case_split".
   124 
   125 * Command 'rep_datatype': instead of theorem names the command now
   126 takes a list of terms denoting the constructors of the type to be
   127 represented as datatype.  The characteristic theorems have to be
   128 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   129 have disappeared in favour of existing ones:
   130 
   131     unit_induct                 ~> unit.induct
   132     prod_induct                 ~> prod.induct
   133     sum_induct                  ~> sum.induct
   134     Suc_Suc_eq                  ~> nat.inject
   135     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   136 
   137 * Library/Nat_Infinity: added addition, numeral syntax and more
   138 instantiations for algebraic structures.  Removed some duplicate
   139 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   140 
   141 * ATP selection (E/Vampire/Spass) is now via PG's settings menu.
   142 
   143 
   144 *** HOL-Algebra ***
   145 
   146 * New locales for orders and lattices where the equivalence relation
   147   is not restricted to equality.  INCOMPATIBILITY: all order and
   148   lattice locales use a record structure with field eq for the
   149   equivalence.
   150 
   151 * New theory of factorial domains.
   152 
   153 * Units_l_inv and Units_r_inv are now simprules by default.
   154 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   155 and/or r_inv will now also require deletion of these lemmas.
   156 
   157 * Renamed the following theorems.  INCOMPATIBILITY.
   158 UpperD ~> Upper_memD
   159 LowerD ~> Lower_memD
   160 least_carrier ~> least_closed
   161 greatest_carrier ~> greatest_closed
   162 greatest_Lower_above ~> greatest_Lower_below
   163 one_zero ~> carrier_one_zero
   164 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   165 
   166 
   167 *** HOL-NSA ***
   168 
   169 * Created new image HOL-NSA, containing theories of nonstandard
   170 analysis which were previously part of HOL-Complex.  Entry point
   171 Hyperreal.thy remains valid, but theories formerly using
   172 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   173 
   174 
   175 *** ZF ***
   176 
   177 * Proof of Zorn's Lemma for partial orders.
   178 
   179 
   180 *** ML ***
   181  
   182 * Rules and tactics that read instantiations (read_instantiate,
   183 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   184 context, which is required for parsing and type-checking.  Moreover,
   185 the variables are specified as plain indexnames, not string encodings
   186 thereof.  INCOMPATIBILITY.
   187 
   188 * Disposed old type and term read functions (Sign.read_def_typ,
   189 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   190 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   191 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   192 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   193 resort for legacy applications.
   194 
   195 * Antiquotations: block-structured compilation context indicated by
   196 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   197 
   198   @{let ?pat = term}                      - term abbreviation (HO matching)
   199   @{note name = fact}                     - fact abbreviation
   200   @{thm fact}                             - singleton fact (with attributes)
   201   @{thms fact}                            - general fact (with attributes)
   202   @{lemma prop by method}                 - singleton goal
   203   @{lemma prop by meth1 meth2}            - singleton goal
   204   @{lemma prop1 ... propN by method}      - general goal
   205   @{lemma prop1 ... propN by meth1 meth2} - general goal
   206   @{lemma (open) ...}                     - open derivation
   207 
   208 
   209 *** System ***
   210 
   211 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   212 the Isabelle process into a JVM/Scala application.  See
   213 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   214 process wrapper has been discontinued.)
   215 
   216 * Status messages (with exact source position information) are
   217 emitted, if proper markup print mode is enabled.  This allows
   218 user-interface components to provide detailed feedback on internal
   219 prover operations.
   220 
   221 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   222 
   223 
   224 
   225 New in Isabelle2008 (June 2008)
   226 -------------------------------
   227 
   228 *** General ***
   229 
   230 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   231 and updated, with formally checked references as hyperlinks.
   232 
   233 * Theory loader: use_thy (and similar operations) no longer set the
   234 implicit ML context, which was occasionally hard to predict and in
   235 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   236 provides a proper context already.
   237 
   238 * Theory loader: old-style ML proof scripts being *attached* to a thy
   239 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   240 'use' within a theory file will do the job.
   241 
   242 * Name space merge now observes canonical order, i.e. the second space
   243 is inserted into the first one, while existing entries in the first
   244 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   245 swap theory imports.
   246 
   247 * Syntax: symbol \<chi> is now considered a letter.  Potential
   248 INCOMPATIBILITY in identifier syntax etc.
   249 
   250 * Outer syntax: string tokens no longer admit escaped white space,
   251 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   252 white space without escapes.
   253 
   254 * Outer syntax: string tokens may contain arbitrary character codes
   255 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   256 "foo_bar".
   257 
   258 
   259 *** Pure ***
   260 
   261 * Context-dependent token translations.  Default setup reverts locally
   262 fixed variables, and adds hilite markup for undeclared frees.
   263 
   264 * Unused theorems can be found using the new command 'unused_thms'.
   265 There are three ways of invoking it:
   266 
   267 (1) unused_thms
   268      Only finds unused theorems in the current theory.
   269 
   270 (2) unused_thms thy_1 ... thy_n -
   271      Finds unused theorems in the current theory and all of its ancestors,
   272      excluding the theories thy_1 ... thy_n and all of their ancestors.
   273 
   274 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   275      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   276      their ancestors, excluding the theories thy_1 ... thy_n and all of
   277      their ancestors.
   278 
   279 In order to increase the readability of the list produced by
   280 unused_thms, theorems that have been created by a particular instance
   281 of a theory command such as 'inductive' or 'function' are considered
   282 to belong to the same "group", meaning that if at least one theorem in
   283 this group is used, the other theorems in the same group are no longer
   284 reported as unused.  Moreover, if all theorems in the group are
   285 unused, only one theorem in the group is displayed.
   286 
   287 Note that proof objects have to be switched on in order for
   288 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   289 usually the case when using Proof General with the default settings).
   290 
   291 * Authentic naming of facts disallows ad-hoc overwriting of previous
   292 theorems within the same name space.  INCOMPATIBILITY, need to remove
   293 duplicate fact bindings, or even accidental fact duplications.  Note
   294 that tools may maintain dynamically scoped facts systematically, using
   295 PureThy.add_thms_dynamic.
   296 
   297 * Command 'hide' now allows to hide from "fact" name space as well.
   298 
   299 * Eliminated destructive theorem database, simpset, claset, and
   300 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   301 update of theories within ML code.
   302 
   303 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   304 INCOMPATIBILITY, object-logics depending on former Pure require
   305 additional setup PureThy.old_appl_syntax_setup; object-logics
   306 depending on former CPure need to refer to Pure.
   307 
   308 * Commands 'use' and 'ML' are now purely functional, operating on
   309 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   310 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   311 INCOMPATIBILITY.
   312 
   313 * Command 'setup': discontinued implicit version with ML reference.
   314 
   315 * Instantiation target allows for simultaneous specification of class
   316 instance operations together with an instantiation proof.
   317 Type-checking phase allows to refer to class operations uniformly.
   318 See src/HOL/Complex/Complex.thy for an Isar example and
   319 src/HOL/Library/Eval.thy for an ML example.
   320 
   321 * Indexing of literal facts: be more serious about including only
   322 facts from the visible specification/proof context, but not the
   323 background context (locale etc.).  Affects `prop` notation and method
   324 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   325 situations.
   326 
   327 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   328 "(open)" option, which used to expose internal bound variables to the
   329 proof text.
   330 
   331 * Isar statements: removed obsolete case "rule_context".
   332 INCOMPATIBILITY, better use explicit fixes/assumes.
   333 
   334 * Locale proofs: default proof step now includes 'unfold_locales';
   335 hence 'proof' without argument may be used to unfold locale
   336 predicates.
   337 
   338 
   339 *** Document preparation ***
   340 
   341 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   342 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   343 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   344 spot); renamed link color from "darkblue" to "linkcolor" (default
   345 value unchanged, can be redefined via \definecolor); no longer sets
   346 "a4paper" option (unnecessary or even intrusive).
   347 
   348 * Antiquotation @{lemma A method} proves proposition A by the given
   349 method (either a method name or a method name plus (optional) method
   350 arguments in parentheses) and prints A just like @{prop A}.
   351 
   352 
   353 *** HOL ***
   354 
   355 * New primrec package.  Specification syntax conforms in style to
   356 definition/function/....  No separate induction rule is provided.  The
   357 "primrec" command distinguishes old-style and new-style specifications
   358 by syntax.  The former primrec package is now named OldPrimrecPackage.
   359 When adjusting theories, beware: constants stemming from new-style
   360 primrec specifications have authentic syntax.
   361 
   362 * Metis prover is now an order of magnitude faster, and also works
   363 with multithreading.
   364 
   365 * Metis: the maximum number of clauses that can be produced from a
   366 theorem is now given by the attribute max_clauses.  Theorems that
   367 exceed this number are ignored, with a warning printed.
   368 
   369 * Sledgehammer no longer produces structured proofs by default. To
   370 enable, declare [[sledgehammer_full = true]].  Attributes
   371 reconstruction_modulus, reconstruction_sorts renamed
   372 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   373 
   374 * Method "induct_scheme" derives user-specified induction rules
   375 from well-founded induction and completeness of patterns. This factors
   376 out some operations that are done internally by the function package
   377 and makes them available separately.  See
   378 src/HOL/ex/Induction_Scheme.thy for examples.
   379 
   380 * More flexible generation of measure functions for termination
   381 proofs: Measure functions can be declared by proving a rule of the
   382 form "is_measure f" and giving it the [measure_function] attribute.
   383 The "is_measure" predicate is logically meaningless (always true), and
   384 just guides the heuristic.  To find suitable measure functions, the
   385 termination prover sets up the goal "is_measure ?f" of the appropriate
   386 type and generates all solutions by prolog-style backwards proof using
   387 the declared rules.
   388 
   389 This setup also deals with rules like 
   390 
   391   "is_measure f ==> is_measure (list_size f)"
   392 
   393 which accommodates nested datatypes that recurse through lists.
   394 Similar rules are predeclared for products and option types.
   395 
   396 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   397 
   398   INCOMPATIBILITIES:
   399 
   400   - Definitions of overloaded constants on sets have to be replaced by
   401     definitions on => and bool.
   402 
   403   - Some definitions of overloaded operators on sets can now be proved
   404     using the definitions of the operators on => and bool.  Therefore,
   405     the following theorems have been renamed:
   406 
   407       subset_def   -> subset_eq
   408       psubset_def  -> psubset_eq
   409       set_diff_def -> set_diff_eq
   410       Compl_def    -> Compl_eq
   411       Sup_set_def  -> Sup_set_eq
   412       Inf_set_def  -> Inf_set_eq
   413       sup_set_def  -> sup_set_eq
   414       inf_set_def  -> inf_set_eq
   415 
   416   - Due to the incompleteness of the HO unification algorithm, some
   417     rules such as subst may require manual instantiation, if some of
   418     the unknowns in the rule is a set.
   419 
   420   - Higher order unification and forward proofs:
   421     The proof pattern
   422 
   423       have "P (S::'a set)" <...>
   424       then have "EX S. P S" ..
   425 
   426     no longer works (due to the incompleteness of the HO unification
   427     algorithm) and must be replaced by the pattern
   428 
   429       have "EX S. P S"
   430       proof
   431         show "P S" <...>
   432       qed
   433 
   434   - Calculational reasoning with subst (or similar rules):
   435     The proof pattern
   436 
   437       have "P (S::'a set)" <...>
   438       also have "S = T" <...>
   439       finally have "P T" .
   440 
   441     no longer works (for similar reasons as the previous example) and
   442     must be replaced by something like
   443 
   444       have "P (S::'a set)" <...>
   445       moreover have "S = T" <...>
   446       ultimately have "P T" by simp
   447 
   448   - Tactics or packages written in ML code:
   449     Code performing pattern matching on types via
   450 
   451       Type ("set", [T]) => ...
   452 
   453     must be rewritten. Moreover, functions like strip_type or
   454     binder_types no longer return the right value when applied to a
   455     type of the form
   456 
   457       T1 => ... => Tn => U => bool
   458 
   459     rather than
   460 
   461       T1 => ... => Tn => U set
   462 
   463 * Merged theories Wellfounded_Recursion, Accessible_Part and
   464 Wellfounded_Relations to theory Wellfounded.
   465 
   466 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   467 
   468 * Class finite no longer treats UNIV as class parameter.  Use class
   469 enum from theory Library/Enum instead to achieve a similar effect.
   470 INCOMPATIBILITY.
   471 
   472 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   473 and "Cons".  INCOMPATIBILITY.
   474 
   475 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   476 Potential INCOMPATIBILITY.
   477 
   478 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   479 injective_fst_snd removed, use split_eta and prod_eqI instead.
   480 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   481 
   482 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   483 the same name in theory Orderings:
   484 
   485   less_trans
   486   less_linear
   487   le_imp_less_or_eq
   488   le_less_trans
   489   less_le_trans
   490   less_not_sym
   491   less_asym
   492 
   493 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
   494 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
   495 and different variable names.
   496 
   497 * Library/Option_ord.thy: Canonical order on option type.
   498 
   499 * Library/RBT.thy: Red-black trees, an efficient implementation of
   500 finite maps.
   501 
   502 * Library/Countable.thy: Type class for countable types.
   503 
   504 * Theory Int: The representation of numerals has changed.  The infix
   505 operator BIT and the bit datatype with constructors B0 and B1 have
   506 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
   507 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
   508 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
   509 accordingly.
   510 
   511 * Theory Nat: definition of <= and < on natural numbers no longer
   512 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
   513 le_def and less_def have disappeared.  Consider lemmas not_less
   514 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
   515 
   516 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
   517 (whose purpose mainly is for various fold_set functionals) have been
   518 abandoned in favor of the existing algebraic classes
   519 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
   520 lower_semilattice (resp. upper_semilattice) and linorder.
   521 INCOMPATIBILITY.
   522 
   523 * Theory Transitive_Closure: induct and cases rules now declare proper
   524 case_names ("base" and "step").  INCOMPATIBILITY.
   525 
   526 * Theorem Inductive.lfp_ordinal_induct generalized to complete
   527 lattices.  The form set-specific version is available as
   528 Inductive.lfp_ordinal_induct_set.
   529 
   530 * Renamed theorems "power.simps" to "power_int.simps".
   531 INCOMPATIBILITY.
   532 
   533 * Class semiring_div provides basic abstract properties of semirings
   534 with division and modulo operations.  Subsumes former class dvd_mod.
   535 
   536 * Merged theories IntDef, Numeral and IntArith into unified theory
   537 Int.  INCOMPATIBILITY.
   538 
   539 * Theory Library/Code_Index: type "index" now represents natural
   540 numbers rather than integers.  INCOMPATIBILITY.
   541 
   542 * New class "uminus" with operation "uminus" (split of from class
   543 "minus" which now only has operation "minus", binary).
   544 INCOMPATIBILITY.
   545 
   546 * Constants "card", "internal_split", "option_map" now with authentic
   547 syntax.  INCOMPATIBILITY.
   548 
   549 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
   550 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
   551 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
   552 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
   553 Sup_set_def, le_def, less_def, option_map_def now with object
   554 equality.  INCOMPATIBILITY.
   555 
   556 * Records. Removed K_record, and replaced it by pure lambda term
   557 %x. c. The simplifier setup is now more robust against eta expansion.
   558 INCOMPATIBILITY: in cases explicitly referring to K_record.
   559 
   560 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
   561 
   562 * Library/ListVector: new theory of arithmetic vector operations.
   563 
   564 * Library/Order_Relation: new theory of various orderings as sets of
   565 pairs.  Defines preorders, partial orders, linear orders and
   566 well-orders on sets and on types.
   567 
   568 
   569 *** ZF ***
   570 
   571 * Renamed some theories to allow to loading both ZF and HOL in the
   572 same session:
   573 
   574   Datatype  -> Datatype_ZF
   575   Inductive -> Inductive_ZF
   576   Int       -> Int_ZF
   577   IntDiv    -> IntDiv_ZF
   578   Nat       -> Nat_ZF
   579   List      -> List_ZF
   580   Main      -> Main_ZF
   581 
   582 INCOMPATIBILITY: ZF theories that import individual theories below
   583 Main might need to be adapted.  Regular theory Main is still
   584 available, as trivial extension of Main_ZF.
   585 
   586 
   587 *** ML ***
   588 
   589 * ML within Isar: antiquotation @{const name} or @{const
   590 name(typargs)} produces statically-checked Const term.
   591 
   592 * Functor NamedThmsFun: data is available to the user as dynamic fact
   593 (of the same name).  Removed obsolete print command.
   594 
   595 * Removed obsolete "use_legacy_bindings" function.
   596 
   597 * The ``print mode'' is now a thread-local value derived from a global
   598 template (the former print_mode reference), thus access becomes
   599 non-critical.  The global print_mode reference is for session
   600 management only; user-code should use print_mode_value,
   601 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
   602 
   603 * Functions system/system_out provide a robust way to invoke external
   604 shell commands, with propagation of interrupts (requires Poly/ML 5.2).
   605 Do not use OS.Process.system etc. from the basis library!
   606 
   607 
   608 *** System ***
   609 
   610 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
   611 in accordance with Proof General 3.7, which prefers GNU emacs.
   612 
   613 * isatool tty runs Isabelle process with plain tty interaction;
   614 optional line editor may be specified via ISABELLE_LINE_EDITOR
   615 setting, the default settings attempt to locate "ledit" and "rlwrap".
   616 
   617 * isatool browser now works with Cygwin as well, using general
   618 "javapath" function defined in Isabelle process environment.
   619 
   620 * YXML notation provides a simple and efficient alternative to
   621 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
   622 isatool yxml as described in the Isabelle system manual.
   623 
   624 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
   625 provides general wrapper for managing an Isabelle process in a robust
   626 fashion, with ``cooked'' output from stdin/stderr.
   627 
   628 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
   629 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
   630 
   631 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
   632 way of changing the user's settings is via
   633 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
   634 script.
   635 
   636 * Multithreading.max_threads := 0 refers to the number of actual CPU
   637 cores of the underlying machine, which is a good starting point for
   638 optimal performance tuning.  The corresponding usedir option -M allows
   639 "max" as an alias for "0".  WARNING: does not work on certain versions
   640 of Mac OS (with Poly/ML 5.1).
   641 
   642 * isabelle-process: non-ML sessions are run with "nice", to reduce the
   643 adverse effect of Isabelle flooding interactive front-ends (notably
   644 ProofGeneral / XEmacs).
   645 
   646 
   647 
   648 New in Isabelle2007 (November 2007)
   649 -----------------------------------
   650 
   651 *** General ***
   652 
   653 * More uniform information about legacy features, notably a
   654 warning/error of "Legacy feature: ...", depending on the state of the
   655 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
   656 legacy features will disappear eventually.
   657 
   658 * Theory syntax: the header format ``theory A = B + C:'' has been
   659 discontinued in favour of ``theory A imports B C begin''.  Use isatool
   660 fixheaders to convert existing theory files.  INCOMPATIBILITY.
   661 
   662 * Theory syntax: the old non-Isar theory file format has been
   663 discontinued altogether.  Note that ML proof scripts may still be used
   664 with Isar theories; migration is usually quite simple with the ML
   665 function use_legacy_bindings.  INCOMPATIBILITY.
   666 
   667 * Theory syntax: some popular names (e.g. 'class', 'declaration',
   668 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
   669 quotes.
   670 
   671 * Theory loader: be more serious about observing the static theory
   672 header specifications (including optional directories), but not the
   673 accidental file locations of previously successful loads.  The strict
   674 update policy of former update_thy is now already performed by
   675 use_thy, so the former has been removed; use_thys updates several
   676 theories simultaneously, just as 'imports' within a theory header
   677 specification, but without merging the results.  Potential
   678 INCOMPATIBILITY: may need to refine theory headers and commands
   679 ROOT.ML which depend on load order.
   680 
   681 * Theory loader: optional support for content-based file
   682 identification, instead of the traditional scheme of full physical
   683 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
   684 (cf. the system manual).  The new scheme allows to work with
   685 non-finished theories in persistent session images, such that source
   686 files may be moved later on without requiring reloads.
   687 
   688 * Theory loader: old-style ML proof scripts being *attached* to a thy
   689 file (with the same base name as the theory) are considered a legacy
   690 feature, which will disappear eventually. Even now, the theory loader
   691 no longer maintains dependencies on such files.
   692 
   693 * Syntax: the scope for resolving ambiguities via type-inference is
   694 now limited to individual terms, instead of whole simultaneous
   695 specifications as before. This greatly reduces the complexity of the
   696 syntax module and improves flexibility by separating parsing and
   697 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
   698 'fixes' etc.) are required in rare situations.
   699 
   700 * Syntax: constants introduced by new-style packages ('definition',
   701 'abbreviation' etc.) are passed through the syntax module in
   702 ``authentic mode''. This means that associated mixfix annotations
   703 really stick to such constants, independently of potential name space
   704 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
   705 trees are represented slightly differently, may need to adapt syntax
   706 translations accordingly. Use CONST marker in 'translations' and
   707 @{const_syntax} antiquotation in 'parse_translation' etc.
   708 
   709 * Legacy goal package: reduced interface to the bare minimum required
   710 to keep existing proof scripts running.  Most other user-level
   711 functions are now part of the OldGoals structure, which is *not* open
   712 by default (consider isatool expandshort before open OldGoals).
   713 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
   714 these tend to cause confusion about the actual goal (!) context being
   715 used here, which is not necessarily the same as the_context().
   716 
   717 * Command 'find_theorems': supports "*" wild-card in "name:"
   718 criterion; "with_dups" option.  Certain ProofGeneral versions might
   719 support a specific search form (see ProofGeneral/CHANGES).
   720 
   721 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
   722 by default, which means that "prems" (and also "fixed variables") are
   723 suppressed from proof state output.  Note that the ProofGeneral
   724 settings mechanism allows to change and save options persistently, but
   725 older versions of Isabelle will fail to start up if a negative prems
   726 limit is imposed.
   727 
   728 * Local theory targets may be specified by non-nested blocks of
   729 ``context/locale/class ... begin'' followed by ``end''.  The body may
   730 contain definitions, theorems etc., including any derived mechanism
   731 that has been implemented on top of these primitives.  This concept
   732 generalizes the existing ``theorem (in ...)'' towards more versatility
   733 and scalability.
   734 
   735 * Proof General interface: proper undo of final 'end' command;
   736 discontinued Isabelle/classic mode (ML proof scripts).
   737 
   738 
   739 *** Document preparation ***
   740 
   741 * Added antiquotation @{theory name} which prints the given name,
   742 after checking that it refers to a valid ancestor theory in the
   743 current context.
   744 
   745 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   746 check the given source text as ML type/structure, printing verbatim.
   747 
   748 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   749 "c args == rhs" given in the current context.  (Any number of
   750 arguments may be given on the LHS.)
   751 
   752 
   753 *** Pure ***
   754 
   755 * The 'class' package offers a combination of axclass and locale to
   756 achieve Haskell-like type classes in Isabelle.  Definitions and
   757 theorems within a class context produce both relative results (with
   758 implicit parameters according to the locale context), and polymorphic
   759 constants with qualified polymorphism (according to the class
   760 context).  Within the body context of a 'class' target, a separate
   761 syntax layer ("user space type system") takes care of converting
   762 between global polymorphic consts and internal locale representation.
   763 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   764 "isatool doc classes" provides a tutorial.
   765 
   766 * Generic code generator framework allows to generate executable
   767 code for ML and Haskell (including Isabelle classes).  A short usage
   768 sketch:
   769 
   770     internal compilation:
   771         export_code <list of constants (term syntax)> in SML
   772     writing SML code to a file:
   773         export_code <list of constants (term syntax)> in SML <filename>
   774     writing OCaml code to a file:
   775         export_code <list of constants (term syntax)> in OCaml <filename>
   776     writing Haskell code to a bunch of files:
   777         export_code <list of constants (term syntax)> in Haskell <filename>
   778 
   779     evaluating closed propositions to True/False using code generation:
   780         method ``eval''
   781 
   782 Reasonable default setup of framework in HOL.
   783 
   784 Theorem attributs for selecting and transforming function equations theorems:
   785 
   786     [code fun]:        select a theorem as function equation for a specific constant
   787     [code fun del]:    deselect a theorem as function equation for a specific constant
   788     [code inline]:     select an equation theorem for unfolding (inlining) in place
   789     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   790 
   791 User-defined serializations (target in {SML, OCaml, Haskell}):
   792 
   793     code_const <and-list of constants (term syntax)>
   794       {(target) <and-list of const target syntax>}+
   795 
   796     code_type <and-list of type constructors>
   797       {(target) <and-list of type target syntax>}+
   798 
   799     code_instance <and-list of instances>
   800       {(target)}+
   801         where instance ::= <type constructor> :: <class>
   802 
   803     code_class <and_list of classes>
   804       {(target) <and-list of class target syntax>}+
   805         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   806 
   807 code_instance and code_class only are effective to target Haskell.
   808 
   809 For example usage see src/HOL/ex/Codegenerator.thy and
   810 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   811 generation from Isabelle/HOL theories is available via "isatool doc
   812 codegen".
   813 
   814 * Code generator: consts in 'consts_code' Isar commands are now
   815 referred to by usual term syntax (including optional type
   816 annotations).
   817 
   818 * Command 'no_translations' removes translation rules from theory
   819 syntax.
   820 
   821 * Overloaded definitions are now actually checked for acyclic
   822 dependencies.  The overloading scheme is slightly more general than
   823 that of Haskell98, although Isabelle does not demand an exact
   824 correspondence to type class and instance declarations.
   825 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   826 exotic versions of overloading -- at the discretion of the user!
   827 
   828 Polymorphic constants are represented via type arguments, i.e. the
   829 instantiation that matches an instance against the most general
   830 declaration given in the signature.  For example, with the declaration
   831 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   832 as c(nat).  Overloading is essentially simultaneous structural
   833 recursion over such type arguments.  Incomplete specification patterns
   834 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   835 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   836 Command 'print_theory' outputs the normalized system of recursive
   837 equations, see section "definitions".
   838 
   839 * Configuration options are maintained within the theory or proof
   840 context (with name and type bool/int/string), providing a very simple
   841 interface to a poor-man's version of general context data.  Tools may
   842 declare options in ML (e.g. using Attrib.config_int) and then refer to
   843 these values using Config.get etc.  Users may change options via an
   844 associated attribute of the same name.  This form of context
   845 declaration works particularly well with commands 'declare' or
   846 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   847 very easy to avoid global references, which would not observe Isar
   848 toplevel undo/redo and fail to work with multithreading.
   849 
   850 Various global ML references of Pure and HOL have been turned into
   851 configuration options:
   852 
   853   Unify.search_bound		unify_search_bound
   854   Unify.trace_bound		unify_trace_bound
   855   Unify.trace_simp		unify_trace_simp
   856   Unify.trace_types		unify_trace_types
   857   Simplifier.simp_depth_limit	simp_depth_limit
   858   Blast.depth_limit		blast_depth_limit
   859   DatatypeProp.dtK		datatype_distinctness_limit
   860   fast_arith_neq_limit  	fast_arith_neq_limit
   861   fast_arith_split_limit	fast_arith_split_limit
   862 
   863 * Named collections of theorems may be easily installed as context
   864 data using the functor NamedThmsFun (see also
   865 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   866 attributes; there is also a toplevel print command.  This facility is
   867 just a common case of general context data, which is the preferred way
   868 for anything more complex than just a list of facts in canonical
   869 order.
   870 
   871 * Isar: command 'declaration' augments a local theory by generic
   872 declaration functions written in ML.  This enables arbitrary content
   873 being added to the context, depending on a morphism that tells the
   874 difference of the original declaration context wrt. the application
   875 context encountered later on.
   876 
   877 * Isar: proper interfaces for simplification procedures.  Command
   878 'simproc_setup' declares named simprocs (with match patterns, and body
   879 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   880 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   881 
   882 * Isar: an extra pair of brackets around attribute declarations
   883 abbreviates a theorem reference involving an internal dummy fact,
   884 which will be ignored later --- only the effect of the attribute on
   885 the background context will persist.  This form of in-place
   886 declarations is particularly useful with commands like 'declare' and
   887 'using', for example ``have A using [[simproc a]] by simp''.
   888 
   889 * Isar: method "assumption" (and implicit closing of subproofs) now
   890 takes simple non-atomic goal assumptions into account: after applying
   891 an assumption as a rule the resulting subgoals are solved by atomic
   892 assumption steps.  This is particularly useful to finish 'obtain'
   893 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   894 without referring to the original premise "!!x. P x ==> thesis" in the
   895 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   896 more permissive.
   897 
   898 * Isar: implicit use of prems from the Isar proof context is
   899 considered a legacy feature.  Common applications like ``have A .''
   900 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   901 referencing facts explicitly here improves readability and
   902 maintainability of proof texts.
   903 
   904 * Isar: improper proof element 'guess' is like 'obtain', but derives
   905 the obtained context from the course of reasoning!  For example:
   906 
   907   assume "EX x y. A x & B y"   -- "any previous fact"
   908   then guess x and y by clarify
   909 
   910 This technique is potentially adventurous, depending on the facts and
   911 proof tools being involved here.
   912 
   913 * Isar: known facts from the proof context may be specified as literal
   914 propositions, using ASCII back-quote syntax.  This works wherever
   915 named facts used to be allowed so far, in proof commands, proof
   916 methods, attributes etc.  Literal facts are retrieved from the context
   917 according to unification of type and term parameters.  For example,
   918 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   919 theorems in the current context, then these are valid literal facts:
   920 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   921 
   922 There is also a proof method "fact" which does the same composition
   923 for explicit goal states, e.g. the following proof texts coincide with
   924 certain special cases of literal facts:
   925 
   926   have "A" by fact                 ==  note `A`
   927   have "A ==> B" by fact           ==  note `A ==> B`
   928   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   929   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   930 
   931 * Isar: ":" (colon) is no longer a symbolic identifier character in
   932 outer syntax.  Thus symbolic identifiers may be used without
   933 additional white space in declarations like this: ``assume *: A''.
   934 
   935 * Isar: 'print_facts' prints all local facts of the current context,
   936 both named and unnamed ones.
   937 
   938 * Isar: 'def' now admits simultaneous definitions, e.g.:
   939 
   940   def x == "t" and y == "u"
   941 
   942 * Isar: added command 'unfolding', which is structurally similar to
   943 'using', but affects both the goal state and facts by unfolding given
   944 rewrite rules.  Thus many occurrences of the 'unfold' method or
   945 'unfolded' attribute may be replaced by first-class proof text.
   946 
   947 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   948 and command 'unfolding' now all support object-level equalities
   949 (potentially conditional).  The underlying notion of rewrite rule is
   950 analogous to the 'rule_format' attribute, but *not* that of the
   951 Simplifier (which is usually more generous).
   952 
   953 * Isar: the new attribute [rotated n] (default n = 1) rotates the
   954 premises of a theorem by n. Useful in conjunction with drule.
   955 
   956 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   957 method expression within a sandbox consisting of the first N
   958 sub-goals, which need to exist.  For example, ``simp_all [3]''
   959 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   960 simplifies all new goals that emerge from applying rule foo to the
   961 originally first one.
   962 
   963 * Isar: schematic goals are no longer restricted to higher-order
   964 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   965 expected.
   966 
   967 * Isar: the conclusion of a long theorem statement is now either
   968 'shows' (a simultaneous conjunction, as before), or 'obtains'
   969 (essentially a disjunction of cases with local parameters and
   970 assumptions).  The latter allows to express general elimination rules
   971 adequately; in this notation common elimination rules look like this:
   972 
   973   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   974     assumes "EX x. P x"
   975     obtains x where "P x"
   976 
   977   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   978     assumes "A & B"
   979     obtains A and B
   980 
   981   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   982     assumes "A | B"
   983     obtains
   984       A
   985     | B
   986 
   987 The subsequent classical rules even refer to the formal "thesis"
   988 explicitly:
   989 
   990   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   991     obtains "~ thesis"
   992 
   993   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   994     obtains "thesis ==> something"
   995 
   996 The actual proof of an 'obtains' statement is analogous to that of the
   997 Isar proof element 'obtain', only that there may be several cases.
   998 Optional case names may be specified in parentheses; these will be
   999 available both in the present proof and as annotations in the
  1000 resulting rule, for later use with the 'cases' method (cf. attribute
  1001 case_names).
  1002 
  1003 * Isar: the assumptions of a long theorem statement are available as
  1004 "assms" fact in the proof context.  This is more appropriate than the
  1005 (historical) "prems", which refers to all assumptions of the current
  1006 context, including those from the target locale, proof body etc.
  1007 
  1008 * Isar: 'print_statement' prints theorems from the current theory or
  1009 proof context in long statement form, according to the syntax of a
  1010 top-level lemma.
  1011 
  1012 * Isar: 'obtain' takes an optional case name for the local context
  1013 introduction rule (default "that").
  1014 
  1015 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1016 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1017 to occur.
  1018 
  1019 * Pure: syntax "CONST name" produces a fully internalized constant
  1020 according to the current context.  This is particularly useful for
  1021 syntax translations that should refer to internal constant
  1022 representations independently of name spaces.
  1023 
  1024 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1025 instead of "FOO ". This allows multiple binder declarations to coexist
  1026 in the same context.  INCOMPATIBILITY.
  1027 
  1028 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1029 primitive that also works in a locale context (both for constants and
  1030 fixed variables). Type declaration and internal syntactic representation
  1031 of given constants retrieved from the context. Likewise, the
  1032 'no_notation' command allows to remove given syntax annotations from the
  1033 current context.
  1034 
  1035 * Isar/locales: new derived specification elements 'axiomatization',
  1036 'definition', 'abbreviation', which support type-inference, admit
  1037 object-level specifications (equality, equivalence).  See also the
  1038 isar-ref manual.  Examples:
  1039 
  1040   axiomatization
  1041     eq  (infix "===" 50) where
  1042     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1043 
  1044   definition "f x y = x + y + 1"
  1045   definition g where "g x = f x x"
  1046 
  1047   abbreviation
  1048     neq  (infix "=!=" 50) where
  1049     "x =!= y == ~ (x === y)"
  1050 
  1051 These specifications may be also used in a locale context.  Then the
  1052 constants being introduced depend on certain fixed parameters, and the
  1053 constant name is qualified by the locale base name.  An internal
  1054 abbreviation takes care for convenient input and output, making the
  1055 parameters implicit and using the original short name.  See also
  1056 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1057 entities from a monomorphic theory.
  1058 
  1059 Presently, abbreviations are only available 'in' a target locale, but
  1060 not inherited by general import expressions.  Also note that
  1061 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1062 'translations' in common applications.  The "no_abbrevs" print mode
  1063 prevents folding of abbreviations in term output.
  1064 
  1065 Concrete syntax is attached to specified constants in internal form,
  1066 independently of name spaces.  The parse tree representation is
  1067 slightly different -- use 'notation' instead of raw 'syntax', and
  1068 'translations' with explicit "CONST" markup to accommodate this.
  1069 
  1070 * Pure/Isar: unified syntax for new-style specification mechanisms
  1071 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1072 full type inference and dummy patterns ("_").  For example:
  1073 
  1074   definition "K x _ = x"
  1075 
  1076   inductive conj for A B
  1077   where "A ==> B ==> conj A B"
  1078 
  1079 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1080 the current context.  Print mode "no_abbrevs" prevents inversion of
  1081 abbreviations on output.
  1082 
  1083 * Isar/locales: improved parameter handling: use of locales "var" and
  1084 "struct" no longer necessary; - parameter renamings are no longer
  1085 required to be injective.  For example, this allows to define
  1086 endomorphisms as locale endom = homom mult mult h.
  1087 
  1088 * Isar/locales: changed the way locales with predicates are defined.
  1089 Instead of accumulating the specification, the imported expression is
  1090 now an interpretation.  INCOMPATIBILITY: different normal form of
  1091 locale expressions.  In particular, in interpretations of locales with
  1092 predicates, goals repesenting already interpreted fragments are not
  1093 removed automatically.  Use methods `intro_locales' and
  1094 `unfold_locales'; see below.
  1095 
  1096 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1097 provide backward reasoning on locales predicates.  The methods are
  1098 aware of interpretations and discharge corresponding goals.
  1099 `intro_locales' is less aggressive then `unfold_locales' and does not
  1100 unfold predicates to assumptions.
  1101 
  1102 * Isar/locales: the order in which locale fragments are accumulated
  1103 has changed.  This enables to override declarations from fragments due
  1104 to interpretations -- for example, unwanted simp rules.
  1105 
  1106 * Isar/locales: interpretation in theories and proof contexts has been
  1107 extended.  One may now specify (and prove) equations, which are
  1108 unfolded in interpreted theorems.  This is useful for replacing
  1109 defined concepts (constants depending on locale parameters) by
  1110 concepts already existing in the target context.  Example:
  1111 
  1112   interpretation partial_order ["op <= :: [int, int] => bool"]
  1113     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1114 
  1115 Typically, the constant `partial_order.less' is created by a
  1116 definition specification element in the context of locale
  1117 partial_order.
  1118 
  1119 * Method "induct": improved internal context management to support
  1120 local fixes and defines on-the-fly. Thus explicit meta-level
  1121 connectives !!  and ==> are rarely required anymore in inductive goals
  1122 (using object-logic connectives for this purpose has been long
  1123 obsolete anyway). Common proof patterns are explained in
  1124 src/HOL/Induct/Common_Patterns.thy, see also
  1125 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1126 examples.
  1127 
  1128 * Method "induct": improved handling of simultaneous goals. Instead of
  1129 introducing object-level conjunction, the statement is now split into
  1130 several conclusions, while the corresponding symbolic cases are nested
  1131 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1132 see src/HOL/Induct/Common_Patterns.thy, for example.
  1133 
  1134 * Method "induct": mutual induction rules are now specified as a list
  1135 of rule sharing the same induction cases. HOL packages usually provide
  1136 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1137 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1138 mutual induction rules differently, i.e. like this:
  1139 
  1140   (induct rule: foo_bar.inducts)
  1141   (induct set: foo bar)
  1142   (induct pred: foo bar)
  1143   (induct type: foo bar)
  1144 
  1145 The ML function ProjectRule.projections turns old-style rules into the
  1146 new format.
  1147 
  1148 * Method "coinduct": dual of induction, see
  1149 src/HOL/Library/Coinductive_List.thy for various examples.
  1150 
  1151 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1152 considered a legacy feature.
  1153 
  1154 * Attribute "symmetric" produces result with standardized schematic
  1155 variables (index 0).  Potential INCOMPATIBILITY.
  1156 
  1157 * Simplifier: by default the simplifier trace only shows top level
  1158 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1159 default. Thus there is less danger of being flooded by the trace. The
  1160 trace indicates where parts have been suppressed.
  1161   
  1162 * Provers/classical: removed obsolete classical version of elim_format
  1163 attribute; classical elim/dest rules are now treated uniformly when
  1164 manipulating the claset.
  1165 
  1166 * Provers/classical: stricter checks to ensure that supplied intro,
  1167 dest and elim rules are well-formed; dest and elim rules must have at
  1168 least one premise.
  1169 
  1170 * Provers/classical: attributes dest/elim/intro take an optional
  1171 weight argument for the rule (just as the Pure versions).  Weights are
  1172 ignored by automated tools, but determine the search order of single
  1173 rule steps.
  1174 
  1175 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1176 where the body does not mention the bound variable.  Note that dummy
  1177 patterns implicitly depend on their context of bounds, which makes
  1178 "{_. _}" match any set comprehension as expected.  Potential
  1179 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1180 constant "_idtdummy" in the binding position.
  1181 
  1182 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1183 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1184 for example "A -> B" => "Pi A (%_. B)".
  1185 
  1186 * Pure: 'class_deps' command visualizes the subclass relation, using
  1187 the graph browser tool.
  1188 
  1189 * Pure: 'print_theory' now suppresses certain internal declarations by
  1190 default; use '!' option for full details.
  1191 
  1192 
  1193 *** HOL ***
  1194 
  1195 * Method "metis" proves goals by applying the Metis general-purpose
  1196 resolution prover (see also http://gilith.com/software/metis/).
  1197 Examples are in the directory MetisExamples.  WARNING: the
  1198 Isabelle/HOL-Metis integration does not yet work properly with
  1199 multi-threading.
  1200   
  1201 * Command 'sledgehammer' invokes external automatic theorem provers as
  1202 background processes.  It generates calls to the "metis" method if
  1203 successful. These can be pasted into the proof.  Users do not have to
  1204 wait for the automatic provers to return.  WARNING: does not really
  1205 work with multi-threading.
  1206 
  1207 * New "auto_quickcheck" feature tests outermost goal statements for
  1208 potential counter-examples.  Controlled by ML references
  1209 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1210 5000 milliseconds).  Fails silently if statements is outside of
  1211 executable fragment, or any other codgenerator problem occurs.
  1212 
  1213 * New constant "undefined" with axiom "undefined x = undefined".
  1214 
  1215 * Added class "HOL.eq", allowing for code generation with polymorphic
  1216 equality.
  1217 
  1218 * Some renaming of class constants due to canonical name prefixing in
  1219 the new 'class' package:
  1220 
  1221     HOL.abs ~> HOL.abs_class.abs
  1222     HOL.divide ~> HOL.divide_class.divide
  1223     0 ~> HOL.zero_class.zero
  1224     1 ~> HOL.one_class.one
  1225     op + ~> HOL.plus_class.plus
  1226     op - ~> HOL.minus_class.minus
  1227     uminus ~> HOL.minus_class.uminus
  1228     op * ~> HOL.times_class.times
  1229     op < ~> HOL.ord_class.less
  1230     op <= > HOL.ord_class.less_eq
  1231     Nat.power ~> Power.power_class.power
  1232     Nat.size ~> Nat.size_class.size
  1233     Numeral.number_of ~> Numeral.number_class.number_of
  1234     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1235     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1236     Orderings.min ~> Orderings.ord_class.min
  1237     Orderings.max ~> Orderings.ord_class.max
  1238     Divides.op div ~> Divides.div_class.div
  1239     Divides.op mod ~> Divides.div_class.mod
  1240     Divides.op dvd ~> Divides.div_class.dvd
  1241 
  1242 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1243 
  1244 a) User-defined constants using any of the names "plus", "minus",
  1245 "times", "less" or "less_eq". The standard syntax translations for
  1246 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1247 names.
  1248 
  1249 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1250 INCOMPATIBILITY: use more specific names.
  1251 
  1252 c) Permutative equations (e.g. "a + b = b + a")
  1253 Since the change of names also changes the order of terms, permutative
  1254 rewrite rules may get applied in a different order. Experience shows
  1255 that this is rarely the case (only two adaptions in the whole Isabelle
  1256 distribution).  INCOMPATIBILITY: rewrite proofs
  1257 
  1258 d) ML code directly refering to constant names
  1259 This in general only affects hand-written proof tactics, simprocs and
  1260 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1261 Consider using @{const_name} antiquotation.
  1262 
  1263 * New class "default" with associated constant "default".
  1264 
  1265 * Function "sgn" is now overloaded and available on int, real, complex
  1266 (and other numeric types), using class "sgn".  Two possible defs of
  1267 sgn are given as equational assumptions in the classes sgn_if and
  1268 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1269 INCOMPATIBILITY.
  1270 
  1271 * Locale "partial_order" now unified with class "order" (cf. theory
  1272 Orderings), added parameter "less".  INCOMPATIBILITY.
  1273 
  1274 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1275 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1276 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1277 
  1278 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1279 changed order of proof goals in instance proofs.
  1280 
  1281 * The transitivity reasoner for partial and linear orders is set up
  1282 for classes "order" and "linorder".  Instances of the reasoner are available
  1283 in all contexts importing or interpreting the corresponding locales.
  1284 Method "order" invokes the reasoner separately; the reasoner
  1285 is also integrated with the Simplifier as a solver.  Diagnostic
  1286 command 'print_orders' shows the available instances of the reasoner
  1287 in the current context.
  1288 
  1289 * Localized monotonicity predicate in theory "Orderings"; integrated
  1290 lemmas max_of_mono and min_of_mono with this predicate.
  1291 INCOMPATIBILITY.
  1292 
  1293 * Formulation of theorem "dense" changed slightly due to integration
  1294 with new class dense_linear_order.
  1295 
  1296 * Uniform lattice theory development in HOL.
  1297 
  1298     constants "meet" and "join" now named "inf" and "sup"
  1299     constant "Meet" now named "Inf"
  1300 
  1301     classes "meet_semilorder" and "join_semilorder" now named
  1302       "lower_semilattice" and "upper_semilattice"
  1303     class "lorder" now named "lattice"
  1304     class "comp_lat" now named "complete_lattice"
  1305 
  1306     Instantiation of lattice classes allows explicit definitions
  1307     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1308 
  1309   INCOMPATIBILITY.  Theorem renames:
  1310 
  1311     meet_left_le            ~> inf_le1
  1312     meet_right_le           ~> inf_le2
  1313     join_left_le            ~> sup_ge1
  1314     join_right_le           ~> sup_ge2
  1315     meet_join_le            ~> inf_sup_ord
  1316     le_meetI                ~> le_infI
  1317     join_leI                ~> le_supI
  1318     le_meet                 ~> le_inf_iff
  1319     le_join                 ~> ge_sup_conv
  1320     meet_idempotent         ~> inf_idem
  1321     join_idempotent         ~> sup_idem
  1322     meet_comm               ~> inf_commute
  1323     join_comm               ~> sup_commute
  1324     meet_leI1               ~> le_infI1
  1325     meet_leI2               ~> le_infI2
  1326     le_joinI1               ~> le_supI1
  1327     le_joinI2               ~> le_supI2
  1328     meet_assoc              ~> inf_assoc
  1329     join_assoc              ~> sup_assoc
  1330     meet_left_comm          ~> inf_left_commute
  1331     meet_left_idempotent    ~> inf_left_idem
  1332     join_left_comm          ~> sup_left_commute
  1333     join_left_idempotent    ~> sup_left_idem
  1334     meet_aci                ~> inf_aci
  1335     join_aci                ~> sup_aci
  1336     le_def_meet             ~> le_iff_inf
  1337     le_def_join             ~> le_iff_sup
  1338     join_absorp2            ~> sup_absorb2
  1339     join_absorp1            ~> sup_absorb1
  1340     meet_absorp1            ~> inf_absorb1
  1341     meet_absorp2            ~> inf_absorb2
  1342     meet_join_absorp        ~> inf_sup_absorb
  1343     join_meet_absorp        ~> sup_inf_absorb
  1344     distrib_join_le         ~> distrib_sup_le
  1345     distrib_meet_le         ~> distrib_inf_le
  1346 
  1347     add_meet_distrib_left   ~> add_inf_distrib_left
  1348     add_join_distrib_left   ~> add_sup_distrib_left
  1349     is_join_neg_meet        ~> is_join_neg_inf
  1350     is_meet_neg_join        ~> is_meet_neg_sup
  1351     add_meet_distrib_right  ~> add_inf_distrib_right
  1352     add_join_distrib_right  ~> add_sup_distrib_right
  1353     add_meet_join_distribs  ~> add_sup_inf_distribs
  1354     join_eq_neg_meet        ~> sup_eq_neg_inf
  1355     meet_eq_neg_join        ~> inf_eq_neg_sup
  1356     add_eq_meet_join        ~> add_eq_inf_sup
  1357     meet_0_imp_0            ~> inf_0_imp_0
  1358     join_0_imp_0            ~> sup_0_imp_0
  1359     meet_0_eq_0             ~> inf_0_eq_0
  1360     join_0_eq_0             ~> sup_0_eq_0
  1361     neg_meet_eq_join        ~> neg_inf_eq_sup
  1362     neg_join_eq_meet        ~> neg_sup_eq_inf
  1363     join_eq_if              ~> sup_eq_if
  1364 
  1365     mono_meet               ~> mono_inf
  1366     mono_join               ~> mono_sup
  1367     meet_bool_eq            ~> inf_bool_eq
  1368     join_bool_eq            ~> sup_bool_eq
  1369     meet_fun_eq             ~> inf_fun_eq
  1370     join_fun_eq             ~> sup_fun_eq
  1371     meet_set_eq             ~> inf_set_eq
  1372     join_set_eq             ~> sup_set_eq
  1373     meet1_iff               ~> inf1_iff
  1374     meet2_iff               ~> inf2_iff
  1375     meet1I                  ~> inf1I
  1376     meet2I                  ~> inf2I
  1377     meet1D1                 ~> inf1D1
  1378     meet2D1                 ~> inf2D1
  1379     meet1D2                 ~> inf1D2
  1380     meet2D2                 ~> inf2D2
  1381     meet1E                  ~> inf1E
  1382     meet2E                  ~> inf2E
  1383     join1_iff               ~> sup1_iff
  1384     join2_iff               ~> sup2_iff
  1385     join1I1                 ~> sup1I1
  1386     join2I1                 ~> sup2I1
  1387     join1I1                 ~> sup1I1
  1388     join2I2                 ~> sup1I2
  1389     join1CI                 ~> sup1CI
  1390     join2CI                 ~> sup2CI
  1391     join1E                  ~> sup1E
  1392     join2E                  ~> sup2E
  1393 
  1394     is_meet_Meet            ~> is_meet_Inf
  1395     Meet_bool_def           ~> Inf_bool_def
  1396     Meet_fun_def            ~> Inf_fun_def
  1397     Meet_greatest           ~> Inf_greatest
  1398     Meet_lower              ~> Inf_lower
  1399     Meet_set_def            ~> Inf_set_def
  1400 
  1401     Sup_def                 ~> Sup_Inf
  1402     Sup_bool_eq             ~> Sup_bool_def
  1403     Sup_fun_eq              ~> Sup_fun_def
  1404     Sup_set_eq              ~> Sup_set_def
  1405 
  1406     listsp_meetI            ~> listsp_infI
  1407     listsp_meet_eq          ~> listsp_inf_eq
  1408 
  1409     meet_min                ~> inf_min
  1410     join_max                ~> sup_max
  1411 
  1412 * Added syntactic class "size"; overloaded constant "size" now has
  1413 type "'a::size ==> bool"
  1414 
  1415 * Internal reorganisation of `size' of datatypes: size theorems
  1416 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1417 simplification rules by default!); theorems "prod.size" now named
  1418 "*.size".
  1419 
  1420 * Class "div" now inherits from class "times" rather than "type".
  1421 INCOMPATIBILITY.
  1422 
  1423 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1424 Linorder etc.  have disappeared; operations defined in terms of
  1425 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1426 
  1427 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1428 
  1429 * HOL-Word: New extensive library and type for generic, fixed size
  1430 machine words, with arithemtic, bit-wise, shifting and rotating
  1431 operations, reflection into int, nat, and bool lists, automation for
  1432 linear arithmetic (by automatic reflection into nat or int), including
  1433 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1434 arithmetic type classes, supporting automatic simplification of
  1435 numerals on all operations.
  1436 
  1437 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1438 
  1439 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1440 
  1441 * Code generator library theories:
  1442   - Code_Integer represents HOL integers by big integer literals in target
  1443     languages.
  1444   - Code_Char represents HOL characters by character literals in target
  1445     languages.
  1446   - Code_Char_chr like Code_Char, but also offers treatment of character
  1447     codes; includes Code_Integer.
  1448   - Executable_Set allows to generate code for finite sets using lists.
  1449   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1450     denominator).
  1451   - Executable_Real implements a subset of real numbers, namly those
  1452     representable by rational numbers.
  1453   - Efficient_Nat implements natural numbers by integers, which in general will
  1454     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1455     includes Code_Integer.
  1456   - Code_Index provides an additional datatype index which is mapped to
  1457     target-language built-in integers.
  1458   - Code_Message provides an additional datatype message_string which is isomorphic to
  1459     strings; messages are mapped to target-language strings.
  1460 
  1461 * New package for inductive predicates
  1462 
  1463   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1464 
  1465     inductive
  1466       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1467       for z_1 :: U_1 and ... and z_n :: U_m
  1468     where
  1469       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1470     | ...
  1471 
  1472   with full support for type-inference, rather than
  1473 
  1474     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1475 
  1476     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1477     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1478 
  1479     inductive "s z_1 ... z_m"
  1480     intros
  1481       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1482       ...
  1483 
  1484   For backward compatibility, there is a wrapper allowing inductive
  1485   sets to be defined with the new package via
  1486 
  1487     inductive_set
  1488       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1489       for z_1 :: U_1 and ... and z_n :: U_m
  1490     where
  1491       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1492     | ...
  1493 
  1494   or
  1495 
  1496     inductive_set
  1497       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1498       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1499       for z_1 :: U_1 and ... and z_n :: U_m
  1500     where
  1501       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1502     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1503     | ...
  1504 
  1505   if the additional syntax "p ..." is required.
  1506 
  1507   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1508   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1509 
  1510   INCOMPATIBILITIES:
  1511 
  1512   - Since declaration and definition of inductive sets or predicates
  1513     is no longer separated, abbreviations involving the newly
  1514     introduced sets or predicates must be specified together with the
  1515     introduction rules after the 'where' keyword (see above), rather
  1516     than before the actual inductive definition.
  1517 
  1518   - The variables in induction and elimination rules are now
  1519     quantified in the order of their occurrence in the introduction
  1520     rules, rather than in alphabetical order. Since this may break
  1521     some proofs, these proofs either have to be repaired, e.g. by
  1522     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1523     statements of the form
  1524 
  1525       case (rule_i a_i_1 ... a_i_{k_i})
  1526 
  1527     or the old order of quantification has to be restored by explicitly adding
  1528     meta-level quantifiers in the introduction rules, i.e.
  1529 
  1530       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  1531 
  1532   - The format of the elimination rules is now
  1533 
  1534       p z_1 ... z_m x_1 ... x_n ==>
  1535         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1536         ==> ... ==> P
  1537 
  1538     for predicates and
  1539 
  1540       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1541         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1542         ==> ... ==> P
  1543 
  1544     for sets rather than
  1545 
  1546       x : s z_1 ... z_m ==>
  1547         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1548         ==> ... ==> P
  1549 
  1550     This may require terms in goals to be expanded to n-tuples
  1551     (e.g. using case_tac or simplification with the split_paired_all
  1552     rule) before the above elimination rule is applicable.
  1553 
  1554   - The elimination or case analysis rules for (mutually) inductive
  1555     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1556     list of rules "p_1_..._p_k.elims" is no longer available.
  1557 
  1558 * New package "function"/"fun" for general recursive functions,
  1559 supporting mutual and nested recursion, definitions in local contexts,
  1560 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1561 for small examples, and the separate tutorial on the function
  1562 package. The old recdef "package" is still available as before, but
  1563 users are encouraged to use the new package.
  1564 
  1565 * Method "lexicographic_order" automatically synthesizes termination
  1566 relations as lexicographic combinations of size measures. 
  1567 
  1568 * Case-expressions allow arbitrary constructor-patterns (including
  1569 "_") and take their order into account, like in functional
  1570 programming.  Internally, this is translated into nested
  1571 case-expressions; missing cases are added and mapped to the predefined
  1572 constant "undefined". In complicated cases printing may no longer show
  1573 the original input but the internal form. Lambda-abstractions allow
  1574 the same form of pattern matching: "% pat1 => e1 | ..." is an
  1575 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  1576 variable.
  1577 
  1578 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  1579 is an abbreviation for "of_nat :: nat => int". The simplification
  1580 rules for "of_nat" have been changed to work like "int" did
  1581 previously.  Potential INCOMPATIBILITY:
  1582   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  1583   - of_nat_diff and of_nat_mult are no longer default simp rules
  1584 
  1585 * Method "algebra" solves polynomial equations over (semi)rings using
  1586 Groebner bases. The (semi)ring structure is defined by locales and the
  1587 tool setup depends on that generic context. Installing the method for
  1588 a specific type involves instantiating the locale and possibly adding
  1589 declarations for computation on the coefficients.  The method is
  1590 already instantiated for natural numbers and for the axiomatic class
  1591 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  1592 CALCULEMUS 2007 for the general principles underlying this
  1593 architecture of context-aware proof-tools.
  1594 
  1595 * Method "ferrack" implements quantifier elimination over
  1596 special-purpose dense linear orders using locales (analogous to
  1597 "algebra"). The method is already installed for class
  1598 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  1599 rat, etc.
  1600 
  1601 * Former constant "List.op @" now named "List.append".  Use ML
  1602 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  1603 circumvent possible incompatibilities when working on ML level.
  1604 
  1605 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1606 
  1607 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1608 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1609 
  1610 * New syntax for Haskell-like list comprehension (input only), eg.
  1611 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1612 
  1613 * The special syntax for function "filter" has changed from [x :
  1614 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1615 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1616 
  1617 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1618 defined on nat only, as an abbreviation for [a..<Suc b]
  1619 INCOMPATIBILITY.
  1620 
  1621 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1622 
  1623 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1624 
  1625 * New lemma collection field_simps (an extension of ring_simps) for
  1626 manipulating (in)equations involving division. Multiplies with all
  1627 denominators that can be proved to be non-zero (in equations) or
  1628 positive/negative (in inequations).
  1629 
  1630 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1631 have been improved and renamed to ring_simps, group_simps and
  1632 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1633 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1634 
  1635 * Theory Library/Commutative_Ring: switched from recdef to function
  1636 package; constants add, mul, pow now curried.  Infix syntax for
  1637 algebraic operations.
  1638 
  1639 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1640 INCOMPATIBILITY.
  1641 
  1642 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1643 INCOMPATIBILITY.
  1644 
  1645 * HOL/records: generalised field-update to take a function on the
  1646 field rather than the new value: r(|A := x|) is translated to A_update
  1647 (K x) r The K-combinator that is internally used is called K_record.
  1648 INCOMPATIBILITY: Usage of the plain update functions has to be
  1649 adapted.
  1650  
  1651 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1652 * x = 0, which are required for a semiring.  Richer structures do not
  1653 inherit from semiring_0 anymore, because this property is a theorem
  1654 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1655 there is more to prove, but this is mostly trivial.
  1656 
  1657 * Class "recpower" is generalized to arbitrary monoids, not just
  1658 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1659 commutativity or semiring properties additionally.
  1660 
  1661 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1662 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1663 better use 'abbreviation'.
  1664 
  1665 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1666 
  1667 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1668 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1669 significant changes for setting up numeral syntax for types:
  1670   - New constants Numeral.pred and Numeral.succ instead
  1671       of former Numeral.bin_pred and Numeral.bin_succ.
  1672   - Use integer operations instead of bin_add, bin_mult and so on.
  1673   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1674   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1675 
  1676 See src/HOL/Integ/IntArith.thy for an example setup.
  1677 
  1678 * Command 'normal_form' computes the normal form of a term that may
  1679 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1680 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1681 heavy-duty computations because the functions are compiled to ML
  1682 first.  Correspondingly, a method "normalization" is provided.  See
  1683 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1684 
  1685 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1686 25 like -->); output depends on the "iff" print_mode, the default is
  1687 "A = B" (with priority 50).
  1688 
  1689 * Relations less (<) and less_eq (<=) are also available on type bool.
  1690 Modified syntax to disallow nesting without explicit parentheses,
  1691 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1692 INCOMPATIBILITY.
  1693 
  1694 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1695 
  1696 * Relation composition operator "op O" now has precedence 75 and binds
  1697 stronger than union and intersection. INCOMPATIBILITY.
  1698 
  1699 * The old set interval syntax "{m..n(}" (and relatives) has been
  1700 removed.  Use "{m..<n}" (and relatives) instead.
  1701 
  1702 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1703 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1704 ``declare [[simproc del: neq]]''.
  1705 
  1706 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1707 True/False.
  1708 
  1709 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1710 
  1711 * Theorem setsum_mult renamed to setsum_right_distrib.
  1712 
  1713 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1714 ``rule'' method.
  1715 
  1716 * Reimplemented methods "sat" and "satx", with several improvements:
  1717 goals no longer need to be stated as "<prems> ==> False", equivalences
  1718 (i.e. "=" on type bool) are handled, variable names of the form
  1719 "lit_<n>" are no longer reserved, significant speedup.
  1720 
  1721 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1722 zChaff is still supported as well.
  1723 
  1724 * 'inductive' and 'datatype': provide projections of mutual rules,
  1725 bundled as foo_bar.inducts;
  1726 
  1727 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1728 Library.
  1729 
  1730 * Library: moved theory Accessible_Part to main HOL.
  1731 
  1732 * Library: added theory Coinductive_List of potentially infinite lists
  1733 as greatest fixed-point.
  1734 
  1735 * Library: added theory AssocList which implements (finite) maps as
  1736 association lists.
  1737 
  1738 * Method "evaluation" solves goals (i.e. a boolean expression)
  1739 efficiently by compiling it to ML.  The goal is "proved" (via an
  1740 oracle) if it evaluates to True.
  1741 
  1742 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1743 also when invoked by the simplifier.  This results in the Simplifier
  1744 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1745 Configuration option fast_arith_split_limit=0 recovers the old
  1746 behavior.
  1747 
  1748 * Support for hex (0x20) and binary (0b1001) numerals.
  1749 
  1750 * New method: reify eqs (t), where eqs are equations for an
  1751 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1752 parameter, computes a term s::'b and a list xs::'a list and proves the
  1753 theorem I xs s = t. This is also known as reification or quoting. The
  1754 resulting theorem is applied to the subgoal to substitute t with I xs
  1755 s.  If t is omitted, the subgoal itself is reified.
  1756 
  1757 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1758 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1759 where f is supposed to be a computable function (in the sense of code
  1760 generattion). The method uses reify to compute s and xs as above then
  1761 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1762 r and finally gets the theorem t = r, which is again applied to the
  1763 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1764 
  1765 * Reflection: Automatic reification now handels binding, an example is
  1766 available in src/HOL/ex/ReflectionEx.thy
  1767 
  1768 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  1769 command 'statespace' that is similar to 'record', but introduces an
  1770 abstract specification based on the locale infrastructure instead of
  1771 HOL types.  This leads to extra flexibility in composing state spaces,
  1772 in particular multiple inheritance and renaming of components.
  1773 
  1774 
  1775 *** HOL-Complex ***
  1776 
  1777 * Hyperreal: Functions root and sqrt are now defined on negative real
  1778 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1779 Nonnegativity side conditions have been removed from many lemmas, so
  1780 that more subgoals may now be solved by simplification; potential
  1781 INCOMPATIBILITY.
  1782 
  1783 * Real: new type classes formalize real normed vector spaces and
  1784 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1785 and norm :: 'a => real.
  1786 
  1787 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1788 reals into other types. The overloaded constant Reals :: 'a set is now
  1789 defined as range of_real; potential INCOMPATIBILITY.
  1790 
  1791 * Real: proper support for ML code generation, including 'quickcheck'.
  1792 Reals are implemented as arbitrary precision rationals.
  1793 
  1794 * Hyperreal: Several constants that previously worked only for the
  1795 reals have been generalized, so they now work over arbitrary vector
  1796 spaces. Type annotations may need to be added in some cases; potential
  1797 INCOMPATIBILITY.
  1798 
  1799   Infinitesimal  :: ('a::real_normed_vector) star set
  1800   HFinite        :: ('a::real_normed_vector) star set
  1801   HInfinite      :: ('a::real_normed_vector) star set
  1802   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1803   monad          :: ('a::real_normed_vector) star => 'a star set
  1804   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1805   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1806   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1807   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1808   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1809   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1810   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1811   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1812   sgn            :: 'a::real_normed_vector => 'a
  1813   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1814 
  1815 * Complex: Some complex-specific constants are now abbreviations for
  1816 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1817 hnorm.  Other constants have been entirely removed in favor of the
  1818 polymorphic versions (INCOMPATIBILITY):
  1819 
  1820   approx        <-- capprox
  1821   HFinite       <-- CFinite
  1822   HInfinite     <-- CInfinite
  1823   Infinitesimal <-- CInfinitesimal
  1824   monad         <-- cmonad
  1825   galaxy        <-- cgalaxy
  1826   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1827   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1828   (ns)deriv     <-- (ns)cderiv
  1829 
  1830 
  1831 *** HOL-Algebra ***
  1832 
  1833 * Formalisation of ideals and the quotient construction over rings.
  1834 
  1835 * Order and lattice theory no longer based on records.
  1836 INCOMPATIBILITY.
  1837 
  1838 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1839 greatest_closed.  INCOMPATIBILITY.
  1840 
  1841 * Method algebra is now set up via an attribute.  For examples see
  1842 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1843 of algebraic structures.
  1844 
  1845 * Renamed theory CRing to Ring.
  1846 
  1847 
  1848 *** HOL-Nominal ***
  1849 
  1850 * Substantial, yet incomplete support for nominal datatypes (binding
  1851 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  1852 src/HOL/Nominal/Examples.  Prospective users should consult
  1853 http://isabelle.in.tum.de/nominal/
  1854 
  1855 
  1856 *** ML ***
  1857 
  1858 * ML basics: just one true type int, which coincides with IntInf.int
  1859 (even on SML/NJ).
  1860 
  1861 * ML within Isar: antiquotations allow to embed statically-checked
  1862 formal entities in the source, referring to the context available at
  1863 compile-time.  For example:
  1864 
  1865 ML {* @{sort "{zero,one}"} *}
  1866 ML {* @{typ "'a => 'b"} *}
  1867 ML {* @{term "%x. x"} *}
  1868 ML {* @{prop "x == y"} *}
  1869 ML {* @{ctyp "'a => 'b"} *}
  1870 ML {* @{cterm "%x. x"} *}
  1871 ML {* @{cprop "x == y"} *}
  1872 ML {* @{thm asm_rl} *}
  1873 ML {* @{thms asm_rl} *}
  1874 ML {* @{type_name c} *}
  1875 ML {* @{type_syntax c} *}
  1876 ML {* @{const_name c} *}
  1877 ML {* @{const_syntax c} *}
  1878 ML {* @{context} *}
  1879 ML {* @{theory} *}
  1880 ML {* @{theory Pure} *}
  1881 ML {* @{theory_ref} *}
  1882 ML {* @{theory_ref Pure} *}
  1883 ML {* @{simpset} *}
  1884 ML {* @{claset} *}
  1885 ML {* @{clasimpset} *}
  1886 
  1887 The same works for sources being ``used'' within an Isar context.
  1888 
  1889 * ML in Isar: improved error reporting; extra verbosity with
  1890 ML_Context.trace enabled.
  1891 
  1892 * Pure/General/table.ML: the join operations now works via exceptions
  1893 DUP/SAME instead of type option. This is simpler in simple cases, and
  1894 admits slightly more efficient complex applications.
  1895 
  1896 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1897 use Context.generic instead of just theory.
  1898 
  1899 * Pure: datatype Context.generic joins theory/Proof.context and
  1900 provides some facilities for code that works in either kind of
  1901 context, notably GenericDataFun for uniform theory and proof data.
  1902 
  1903 * Pure: simplified internal attribute type, which is now always
  1904 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  1905 local (Proof.context) attributes have been discontinued, while
  1906 minimizing code duplication. Thm.rule_attribute and
  1907 Thm.declaration_attribute build canonical attributes; see also structure
  1908 Context for further operations on Context.generic, notably
  1909 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  1910 declarations and definitions.
  1911 
  1912 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1913 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1914 init only required for impure data. INCOMPATIBILITY: empty really need
  1915 to be empty (no dependencies on theory content!)
  1916 
  1917 * Pure/kernel: consts certification ignores sort constraints given in
  1918 signature declarations. (This information is not relevant to the
  1919 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  1920 potential INCOMPATIBILITY.
  1921 
  1922 * Pure: axiomatic type classes are now purely definitional, with
  1923 explicit proofs of class axioms and super class relations performed
  1924 internally. See Pure/axclass.ML for the main internal interfaces --
  1925 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1926 AxClass.axiomatize_class/classrel/arity supersede
  1927 Sign.add_classes/classrel/arities.
  1928 
  1929 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1930 global/local versions on theory vs. Proof.context have been
  1931 discontinued; Attrib.syntax and Method.syntax have been adapted
  1932 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1933 attributes, methods, etc.
  1934 
  1935 * Pure: several functions of signature "... -> theory -> theory * ..."
  1936 have been reoriented to "... -> theory -> ... * theory" in order to
  1937 allow natural usage in combination with the ||>, ||>>, |-> and
  1938 fold_map combinators.
  1939 
  1940 * Pure: official theorem names (closed derivations) and additional
  1941 comments (tags) are now strictly separate.  Name hints -- which are
  1942 maintained as tags -- may be attached any time without affecting the
  1943 derivation.
  1944 
  1945 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1946 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1947 achieve the old behaviour.
  1948 
  1949 * Pure: the "Goal" constant is now called "prop", supporting a
  1950 slightly more general idea of ``protecting'' meta-level rule
  1951 statements.
  1952 
  1953 * Pure: Logic.(un)varify only works in a global context, which is now
  1954 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1955 Logic.legacy_(un)varify as temporary workaround.
  1956 
  1957 * Pure: structure Name provides scalable operations for generating
  1958 internal variable names, notably Name.variants etc.  This replaces
  1959 some popular functions from term.ML:
  1960 
  1961   Term.variant		->  Name.variant
  1962   Term.variantlist	->  Name.variant_list
  1963   Term.invent_names	->  Name.invent_list
  1964 
  1965 Note that low-level renaming rarely occurs in new code -- operations
  1966 from structure Variable are used instead (see below).
  1967 
  1968 * Pure: structure Variable provides fundamental operations for proper
  1969 treatment of fixed/schematic variables in a context.  For example,
  1970 Variable.import introduces fixes for schematics of given facts and
  1971 Variable.export reverses the effect (up to renaming) -- this replaces
  1972 various freeze_thaw operations.
  1973 
  1974 * Pure: structure Goal provides simple interfaces for
  1975 init/conclude/finish and tactical prove operations (replacing former
  1976 Tactic.prove).  Goal.prove is the canonical way to prove results
  1977 within a given context; Goal.prove_global is a degraded version for
  1978 theory level goals, including a global Drule.standard.  Note that
  1979 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1980 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1981 in a locale context).
  1982 
  1983 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  1984 and type checking (Syntax.check_term etc.), with common combinations
  1985 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  1986 which are considered legacy and await removal.
  1987 
  1988 * Pure/Syntax: generic interfaces for type unchecking
  1989 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  1990 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  1991 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  1992 available for convenience, but refer to the very same operations using
  1993 a mere theory instead of a full context.
  1994 
  1995 * Isar: simplified treatment of user-level errors, using exception
  1996 ERROR of string uniformly.  Function error now merely raises ERROR,
  1997 without any side effect on output channels.  The Isar toplevel takes
  1998 care of proper display of ERROR exceptions.  ML code may use plain
  1999 handle/can/try; cat_error may be used to concatenate errors like this:
  2000 
  2001   ... handle ERROR msg => cat_error msg "..."
  2002 
  2003 Toplevel ML code (run directly or through the Isar toplevel) may be
  2004 embedded into the Isar toplevel with exception display/debug like
  2005 this:
  2006 
  2007   Isar.toplevel (fn () => ...)
  2008 
  2009 INCOMPATIBILITY, removed special transform_error facilities, removed
  2010 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2011 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2012 -- use plain ERROR instead.
  2013 
  2014 * Isar: theory setup now has type (theory -> theory), instead of a
  2015 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2016 
  2017 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2018 ProofContext.debug/verbose flags.
  2019 
  2020 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2021 theory before entering a proof state.  Transactions now always see a
  2022 quasi-functional intermediate checkpoint, both in interactive and
  2023 batch mode.
  2024 
  2025 * Isar: simplified interfaces for outer syntax.  Renamed
  2026 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2027 OuterSyntax.add_parsers -- this functionality is now included in
  2028 OuterSyntax.command etc.  INCOMPATIBILITY.
  2029 
  2030 * Simplifier: the simpset of a running simplification process now
  2031 contains a proof context (cf. Simplifier.the_context), which is the
  2032 very context that the initial simpset has been retrieved from (by
  2033 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2034 (solver, looper etc.) may depend on arbitrary proof data.
  2035 
  2036 * Simplifier.inherit_context inherits the proof context (plus the
  2037 local bounds) of the current simplification process; any simproc
  2038 etc. that calls the Simplifier recursively should do this!  Removed
  2039 former Simplifier.inherit_bounds, which is already included here --
  2040 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2041 specify an explicit context using Simplifier.context/theory_context.
  2042 
  2043 * Simplifier/Classical Reasoner: more abstract interfaces
  2044 change_simpset/claset for modifying the simpset/claset reference of a
  2045 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2046 INCOMPATIBILITY.
  2047 
  2048 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2049 "Trueprop" etc.
  2050 
  2051 
  2052 *** System ***
  2053 
  2054 * settings: the default heap location within ISABELLE_HOME_USER now
  2055 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2056 Isabelle installations.
  2057 
  2058 * isabelle-process: option -S (secure mode) disables some critical
  2059 operations, notably runtime compilation and evaluation of ML source
  2060 code.
  2061 
  2062 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2063 
  2064 * Support for parallel execution, using native multicore support of
  2065 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2066 independent theories, according to the given theory header
  2067 specifications. The maximum number of worker threads is specified via
  2068 usedir option -M or the "max-threads" setting in Proof General. A
  2069 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2070 to 6 on a 8-core machine.  User-code needs to observe certain
  2071 guidelines for thread-safe programming, see appendix A in the Isar
  2072 Implementation manual.
  2073 
  2074 
  2075 
  2076 New in Isabelle2005 (October 2005)
  2077 ----------------------------------
  2078 
  2079 *** General ***
  2080 
  2081 * Theory headers: the new header syntax for Isar theories is
  2082 
  2083   theory <name>
  2084   imports <theory1> ... <theoryN>
  2085   uses <file1> ... <fileM>
  2086   begin
  2087 
  2088 where the 'uses' part is optional.  The previous syntax
  2089 
  2090   theory <name> = <theory1> + ... + <theoryN>:
  2091 
  2092 will disappear in the next release.  Use isatool fixheaders to convert
  2093 existing theory files.  Note that there is no change in ancient
  2094 non-Isar theories now, but these will disappear soon.
  2095 
  2096 * Theory loader: parent theories can now also be referred to via
  2097 relative and absolute paths.
  2098 
  2099 * Command 'find_theorems' searches for a list of criteria instead of a
  2100 list of constants. Known criteria are: intro, elim, dest, name:string,
  2101 simp:term, and any term. Criteria can be preceded by '-' to select
  2102 theorems that do not match. Intro, elim, dest select theorems that
  2103 match the current goal, name:s selects theorems whose fully qualified
  2104 name contain s, and simp:term selects all simplification rules whose
  2105 lhs match term.  Any other term is interpreted as pattern and selects
  2106 all theorems matching the pattern. Available in ProofGeneral under
  2107 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2108 
  2109   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2110 
  2111 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2112 matching the current goal as introduction rule and not having "HOL."
  2113 in their name (i.e. not being defined in theory HOL).
  2114 
  2115 * Command 'thms_containing' has been discontinued in favour of
  2116 'find_theorems'; INCOMPATIBILITY.
  2117 
  2118 * Communication with Proof General is now 8bit clean, which means that
  2119 Unicode text in UTF-8 encoding may be used within theory texts (both
  2120 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2121 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2122 
  2123   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2124   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2125 
  2126 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2127 Classical Reasoner.  Typical big applications run around 2 times
  2128 faster.
  2129 
  2130 
  2131 *** Document preparation ***
  2132 
  2133 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2134 of raw sources.  Only those symbols that do not require additional
  2135 LaTeX packages (depending on comments in isabellesym.sty) are
  2136 displayed properly, everything else is left verbatim.  isatool display
  2137 and isatool print are used as front ends (these are subject to the
  2138 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2139 
  2140 * Command tags control specific markup of certain regions of text,
  2141 notably folding and hiding.  Predefined tags include "theory" (for
  2142 theory begin and end), "proof" for proof commands, and "ML" for
  2143 commands involving ML code; the additional tags "visible" and
  2144 "invisible" are unused by default.  Users may give explicit tag
  2145 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2146 interpretation of tags is determined by the LaTeX job during document
  2147 preparation: see option -V of isatool usedir, or options -n and -t of
  2148 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2149 \isadroptag.
  2150 
  2151 Several document versions may be produced at the same time via isatool
  2152 usedir (the generated index.html will link all of them).  Typical
  2153 specifications include ''-V document=theory,proof,ML'' to present
  2154 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2155 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2156 these parts without any formal replacement text.  The Isabelle site
  2157 default settings produce ''document'' and ''outline'' versions as
  2158 specified above.
  2159 
  2160 * Several new antiquotations:
  2161 
  2162   @{term_type term} prints a term with its type annotated;
  2163 
  2164   @{typeof term} prints the type of a term;
  2165 
  2166   @{const const} is the same as @{term const}, but checks that the
  2167   argument is a known logical constant;
  2168 
  2169   @{term_style style term} and @{thm_style style thm} print a term or
  2170   theorem applying a "style" to it
  2171 
  2172   @{ML text}
  2173 
  2174 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2175 definitions, equations, inequations etc., 'concl' printing only the
  2176 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2177 to print the specified premise.  TermStyle.add_style provides an ML
  2178 interface for introducing further styles.  See also the "LaTeX Sugar"
  2179 document practical applications.  The ML antiquotation prints
  2180 type-checked ML expressions verbatim.
  2181 
  2182 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2183 and 'text' support optional locale specification '(in loc)', which
  2184 specifies the default context for interpreting antiquotations.  For
  2185 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2186 
  2187 * Option 'locale=NAME' of antiquotations specifies an alternative
  2188 context interpreting the subsequent argument.  For example: @{thm
  2189 [locale=lattice] inf_assoc}.
  2190 
  2191 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2192 a proof context.
  2193 
  2194 * Proper output of antiquotations for theory commands involving a
  2195 proof context (such as 'locale' or 'theorem (in loc) ...').
  2196 
  2197 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2198 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2199 
  2200 * isatool usedir: new option -C (default true) controls whether option
  2201 -D should include a copy of the original document directory; -C false
  2202 prevents unwanted effects such as copying of administrative CVS data.
  2203 
  2204 
  2205 *** Pure ***
  2206 
  2207 * Considerably improved version of 'constdefs' command.  Now performs
  2208 automatic type-inference of declared constants; additional support for
  2209 local structure declarations (cf. locales and HOL records), see also
  2210 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2211 sequential dependencies of definitions within a single 'constdefs'
  2212 section; moreover, the declared name needs to be an identifier.  If
  2213 all fails, consider to fall back on 'consts' and 'defs' separately.
  2214 
  2215 * Improved indexed syntax and implicit structures.  First of all,
  2216 indexed syntax provides a notational device for subscripted
  2217 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2218 expressions.  Secondly, in a local context with structure
  2219 declarations, number indexes \<^sub>n or the empty index (default
  2220 number 1) refer to a certain fixed variable implicitly; option
  2221 show_structs controls printing of implicit structures.  Typical
  2222 applications of these concepts involve record types and locales.
  2223 
  2224 * New command 'no_syntax' removes grammar declarations (and
  2225 translations) resulting from the given syntax specification, which is
  2226 interpreted in the same manner as for the 'syntax' command.
  2227 
  2228 * 'Advanced' translation functions (parse_translation etc.) may depend
  2229 on the signature of the theory context being presently used for
  2230 parsing/printing, see also isar-ref manual.
  2231 
  2232 * Improved 'oracle' command provides a type-safe interface to turn an
  2233 ML expression of type theory -> T -> term into a primitive rule of
  2234 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2235 is already included here); see also FOL/ex/IffExample.thy;
  2236 INCOMPATIBILITY.
  2237 
  2238 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2239 before); "cI" is no longer bound, use "c.intro" instead.
  2240 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2241 axclasses vs. locales.
  2242 
  2243 * Improved internal renaming of symbolic identifiers -- attach primes
  2244 instead of base 26 numbers.
  2245 
  2246 * New flag show_question_marks controls printing of leading question
  2247 marks in schematic variable names.
  2248 
  2249 * In schematic variable names, *any* symbol following \<^isub> or
  2250 \<^isup> is now treated as part of the base name.  For example, the
  2251 following works without printing of awkward ".0" indexes:
  2252 
  2253   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2254     by simp
  2255 
  2256 * Inner syntax includes (*(*nested*) comments*).
  2257 
  2258 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2259 annotations as "(00...)".
  2260 
  2261 * Clear separation of logical types and nonterminals, where the latter
  2262 may only occur in 'syntax' specifications or type abbreviations.
  2263 Before that distinction was only partially implemented via type class
  2264 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2265 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2266 exotic syntax specifications may require further adaption
  2267 (e.g. Cube/Cube.thy).
  2268 
  2269 * Removed obsolete type class "logic", use the top sort {} instead.
  2270 Note that non-logical types should be declared as 'nonterminals'
  2271 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2272 specifications.
  2273 
  2274 * Attributes 'induct' and 'cases': type or set names may now be
  2275 locally fixed variables as well.
  2276 
  2277 * Simplifier: can now control the depth to which conditional rewriting
  2278 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2279 Limit.
  2280 
  2281 * Simplifier: simplification procedures may now take the current
  2282 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2283 interface), which is very useful for calling the Simplifier
  2284 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2285 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2286 low-level mk_simproc no longer applies Logic.varify internally, to
  2287 allow for use in a context of fixed variables.
  2288 
  2289 * thin_tac now works even if the assumption being deleted contains !!
  2290 or ==>.  More generally, erule now works even if the major premise of
  2291 the elimination rule contains !! or ==>.
  2292 
  2293 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2294 
  2295 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2296 from Pure, which contains all common declarations already.  Both
  2297 theories are defined via plain Isabelle/Isar .thy files.
  2298 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2299 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2300 use isatool fixcpure to adapt your theory and ML sources.
  2301 
  2302 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2303 selections of theorems in named facts via index ranges.
  2304 
  2305 * 'print_theorems': in theory mode, really print the difference
  2306 wrt. the last state (works for interactive theory development only),
  2307 in proof mode print all local facts (cf. 'print_facts');
  2308 
  2309 * 'hide': option '(open)' hides only base names.
  2310 
  2311 * More efficient treatment of intermediate checkpoints in interactive
  2312 theory development.
  2313 
  2314 * Code generator is now invoked via code_module (incremental code
  2315 generation) and code_library (modular code generation, ML structures
  2316 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2317 must be quoted when used as identifiers.
  2318 
  2319 * New 'value' command for reading, evaluating and printing terms using
  2320 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2321 quoted when used as identifier.
  2322 
  2323 
  2324 *** Locales ***
  2325 
  2326 * New commands for the interpretation of locale expressions in
  2327 theories (1), locales (2) and proof contexts (3).  These generate
  2328 proof obligations from the expression specification.  After the
  2329 obligations have been discharged, theorems of the expression are added
  2330 to the theory, target locale or proof context.  The synopsis of the
  2331 commands is a follows:
  2332 
  2333   (1) interpretation expr inst
  2334   (2) interpretation target < expr
  2335   (3) interpret expr inst
  2336 
  2337 Interpretation in theories and proof contexts require a parameter
  2338 instantiation of terms from the current context.  This is applied to
  2339 specifications and theorems of the interpreted expression.
  2340 Interpretation in locales only permits parameter renaming through the
  2341 locale expression.  Interpretation is smart in that interpretations
  2342 that are active already do not occur in proof obligations, neither are
  2343 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2344 inspect active interpretations of a particular locale.  For details,
  2345 see the Isar Reference manual.  Examples can be found in
  2346 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2347 
  2348 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2349 'interpret' instead.
  2350 
  2351 * New context element 'constrains' for adding type constraints to
  2352 parameters.
  2353 
  2354 * Context expressions: renaming of parameters with syntax
  2355 redeclaration.
  2356 
  2357 * Locale declaration: 'includes' disallowed.
  2358 
  2359 * Proper static binding of attribute syntax -- i.e. types / terms /
  2360 facts mentioned as arguments are always those of the locale definition
  2361 context, independently of the context of later invocations.  Moreover,
  2362 locale operations (renaming and type / term instantiation) are applied
  2363 to attribute arguments as expected.
  2364 
  2365 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2366 actual attributes; rare situations may require Attrib.attribute to
  2367 embed those attributes into Attrib.src that lack concrete syntax.
  2368 Attribute implementations need to cooperate properly with the static
  2369 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2370 Attrib.XXX_thm etc. already do the right thing without further
  2371 intervention.  Only unusual applications -- such as "where" or "of"
  2372 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2373 on the context and the facts involved -- may have to assign parsed
  2374 values to argument tokens explicitly.
  2375 
  2376 * Changed parameter management in theorem generation for long goal
  2377 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2378 theorem statement in rare situations.
  2379 
  2380 * Locale inspection command 'print_locale' omits notes elements.  Use
  2381 'print_locale!' to have them included in the output.
  2382 
  2383 
  2384 *** Provers ***
  2385 
  2386 * Provers/hypsubst.ML: improved version of the subst method, for
  2387 single-step rewriting: it now works in bound variable contexts. New is
  2388 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2389 rewrite a different subterm than the original subst method, which is
  2390 still available as 'simplesubst'.
  2391 
  2392 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2393 and quasi orders.
  2394 
  2395 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2396 reflexive-transitive closure of relations.
  2397 
  2398 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2399 limit (previously hard-coded with a value of 20) user-definable.
  2400 
  2401 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2402 is peformed already.  Object-logics merely need to finish their
  2403 initial simpset configuration as before.  INCOMPATIBILITY.
  2404 
  2405 
  2406 *** HOL ***
  2407 
  2408 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2409 
  2410   syntax (epsilon)
  2411     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2412 
  2413 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2414 and x-symbol; use option '-m epsilon' to get it actually printed.
  2415 Moreover, the mathematically important symbolic identifier \<epsilon>
  2416 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2417 
  2418 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2419 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2420 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2421 support corresponding Isar calculations.
  2422 
  2423 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2424 instead of ":".
  2425 
  2426 * theory SetInterval: changed the syntax for open intervals:
  2427 
  2428   Old       New
  2429   {..n(}    {..<n}
  2430   {)n..}    {n<..}
  2431   {m..n(}   {m..<n}
  2432   {)m..n}   {m<..n}
  2433   {)m..n(}  {m<..<n}
  2434 
  2435 The old syntax is still supported but will disappear in the next
  2436 release.  For conversion use the following Emacs search and replace
  2437 patterns (these are not perfect but work quite well):
  2438 
  2439   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2440   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2441 
  2442 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2443 equalities in commutative rings; method 'algebra' provides a generic
  2444 interface.
  2445 
  2446 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2447 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2448 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2449 be a tuple pattern.
  2450 
  2451 Some new syntax forms are available:
  2452 
  2453   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2454   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2455   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2456   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2457 
  2458 The latter form "\<Sum>x < k. e" used to be based on a separate
  2459 function "Summation", which has been discontinued.
  2460 
  2461 * theory Finite_Set: in structured induction proofs, the insert case
  2462 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2463 (insert F x)'.
  2464 
  2465 * The 'refute' command has been extended to support a much larger
  2466 fragment of HOL, including axiomatic type classes, constdefs and
  2467 typedefs, inductive datatypes and recursion.
  2468 
  2469 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2470 Requires zChaff with proof generation to be installed.  See
  2471 HOL/ex/SAT_Examples.thy for examples.
  2472 
  2473 * Datatype induction via method 'induct' now preserves the name of the
  2474 induction variable. For example, when proving P(xs::'a list) by
  2475 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2476 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2477 in unstructured proof scripts.
  2478 
  2479 * Reworked implementation of records.  Improved scalability for
  2480 records with many fields, avoiding performance problems for type
  2481 inference. Records are no longer composed of nested field types, but
  2482 of nested extension types. Therefore the record type only grows linear
  2483 in the number of extensions and not in the number of fields.  The
  2484 top-level (users) view on records is preserved.  Potential
  2485 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2486 old record representation. The type generated for a record is called
  2487 <record_name>_ext_type.
  2488 
  2489 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2490 proofs triggered by a record definition or a simproc (if
  2491 quick_and_dirty is enabled).  Definitions of large records can take
  2492 quite long.
  2493 
  2494 New simproc record_upd_simproc for simplification of multiple record
  2495 updates enabled by default.  Moreover, trivial updates are also
  2496 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2497 occasionally, since simplification is more powerful by default.
  2498 
  2499 * typedef: proper support for polymorphic sets, which contain extra
  2500 type-variables in the term.
  2501 
  2502 * Simplifier: automatically reasons about transitivity chains
  2503 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2504 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2505 old proofs break occasionally as simplification may now solve more
  2506 goals than previously.
  2507 
  2508 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2509 present.  Works for all partial orders (class "order"), in particular
  2510 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2511 just like y <= x.
  2512 
  2513 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2514 bound variable or a constant then the let is unfolded.  Otherwise
  2515 first a is simplified to b, and then f b is simplified to g. If
  2516 possible we abstract b from g arriving at "let x = b in h x",
  2517 otherwise we unfold the let and arrive at g.  The simproc can be
  2518 enabled/disabled by the reference use_let_simproc.  Potential
  2519 INCOMPATIBILITY since simplification is more powerful by default.
  2520 
  2521 * Classical reasoning: the meson method now accepts theorems as arguments.
  2522 
  2523 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2524 jobs to provide advice on the provability of subgoals.
  2525 
  2526 * Theory OrderedGroup and Ring_and_Field: various additions and
  2527 improvements to faciliate calculations involving equalities and
  2528 inequalities.
  2529 
  2530 The following theorems have been eliminated or modified
  2531 (INCOMPATIBILITY):
  2532 
  2533   abs_eq             now named abs_of_nonneg
  2534   abs_of_ge_0        now named abs_of_nonneg
  2535   abs_minus_eq       now named abs_of_nonpos
  2536   imp_abs_id         now named abs_of_nonneg
  2537   imp_abs_neg_id     now named abs_of_nonpos
  2538   mult_pos           now named mult_pos_pos
  2539   mult_pos_le        now named mult_nonneg_nonneg
  2540   mult_pos_neg_le    now named mult_nonneg_nonpos
  2541   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2542   mult_neg           now named mult_neg_neg
  2543   mult_neg_le        now named mult_nonpos_nonpos
  2544 
  2545 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2546      
  2547      zero_le_square
  2548      not_square_less_zero 
  2549 
  2550   The following lemmas have been deleted from Real/RealPow:
  2551   
  2552      realpow_zero_zero
  2553      realpow_two
  2554      realpow_less
  2555      zero_le_power
  2556      realpow_two_le
  2557      abs_realpow_two
  2558      realpow_two_abs     
  2559 
  2560 * Theory Parity: added rules for simplifying exponents.
  2561 
  2562 * Theory List:
  2563 
  2564 The following theorems have been eliminated or modified
  2565 (INCOMPATIBILITY):
  2566 
  2567   list_all_Nil       now named list_all.simps(1)
  2568   list_all_Cons      now named list_all.simps(2)
  2569   list_all_conv      now named list_all_iff
  2570   set_mem_eq         now named mem_iff
  2571 
  2572 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  2573 asymptotic "big O" calculations.  See the notes in BigO.thy.
  2574 
  2575 
  2576 *** HOL-Complex ***
  2577 
  2578 * Theory RealDef: better support for embedding natural numbers and
  2579 integers in the reals.
  2580 
  2581 The following theorems have been eliminated or modified
  2582 (INCOMPATIBILITY):
  2583 
  2584   exp_ge_add_one_self  now requires no hypotheses
  2585   real_of_int_add      reversed direction of equality (use [symmetric])
  2586   real_of_int_minus    reversed direction of equality (use [symmetric])
  2587   real_of_int_diff     reversed direction of equality (use [symmetric])
  2588   real_of_int_mult     reversed direction of equality (use [symmetric])
  2589 
  2590 * Theory RComplete: expanded support for floor and ceiling functions.
  2591 
  2592 * Theory Ln is new, with properties of the natural logarithm
  2593 
  2594 * Hyperreal: There is a new type constructor "star" for making
  2595 nonstandard types.  The old type names are now type synonyms:
  2596 
  2597   hypreal = real star
  2598   hypnat = nat star
  2599   hcomplex = complex star
  2600 
  2601 * Hyperreal: Many groups of similarly-defined constants have been
  2602 replaced by polymorphic versions (INCOMPATIBILITY):
  2603 
  2604   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2605 
  2606   starset      <-- starsetNat, starsetC
  2607   *s*          <-- *sNat*, *sc*
  2608   starset_n    <-- starsetNat_n, starsetC_n
  2609   *sn*         <-- *sNatn*, *scn*
  2610   InternalSets <-- InternalNatSets, InternalCSets
  2611 
  2612   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2613   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2614   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2615   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2616   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2617 
  2618 * Hyperreal: Many type-specific theorems have been removed in favor of
  2619 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2620 
  2621   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2622   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2623   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2624   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2625   right_minus <-- hypreal_add_minus
  2626   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2627   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2628   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2629   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2630   mult_1_right <-- hcomplex_mult_one_right
  2631   mult_zero_left <-- hcomplex_mult_zero_left
  2632   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2633   right_distrib <-- hypnat_add_mult_distrib2
  2634   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2635   right_inverse <-- hypreal_mult_inverse
  2636   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2637   order_refl <-- {hypreal,hypnat}_le_refl
  2638   order_trans <-- {hypreal,hypnat}_le_trans
  2639   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2640   order_less_le <-- {hypreal,hypnat}_less_le
  2641   linorder_linear <-- {hypreal,hypnat}_le_linear
  2642   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2643   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2644   add_nonneg_nonneg <-- hypreal_le_add_order
  2645 
  2646 * Hyperreal: Separate theorems having to do with type-specific
  2647 versions of constants have been merged into theorems that apply to the
  2648 new polymorphic constants (INCOMPATIBILITY):
  2649 
  2650   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2651   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2652   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2653   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2654   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2655   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2656   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2657   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2658   STAR_diff <-- {STAR,STARC}_diff
  2659   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2660     STARC_hcomplex_of_complex}_image_subset
  2661   starset_n_Un <-- starset{Nat,C}_n_Un
  2662   starset_n_Int <-- starset{Nat,C}_n_Int
  2663   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2664   starset_n_diff <-- starset{Nat,C}_n_diff
  2665   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2666   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2667   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2668   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2669   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2670   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2671   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2672   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2673   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2674   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2675   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2676   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2677   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2678   starfun_diff <-- starfun{C,RC,CR}_diff
  2679   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2680   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2681   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2682   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2683   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2684   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2685   starfun_Id <-- starfunC_Id
  2686   starfun_approx <-- starfun{Nat,CR}_approx
  2687   starfun_capprox <-- starfun{C,RC}_capprox
  2688   starfun_abs <-- starfunNat_rabs
  2689   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2690   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2691   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2692   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2693   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2694   starfun_add_approx <-- starfunCR_add_approx
  2695   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2696   starfun_divide <-- starfun{C,CR,RC}_divide
  2697   starfun_n <-- starfun{Nat,C}_n
  2698   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2699   starfun_n_add <-- starfun{Nat,C}_n_add
  2700   starfun_n_add_minus <-- starfunNat_n_add_minus
  2701   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2702   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2703   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2704 
  2705   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2706   star_n_minus <-- {hypreal,hcomplex}_minus
  2707   star_n_diff <-- {hypreal,hcomplex}_diff
  2708   star_n_mult <-- {hypreal,hcomplex}_mult
  2709   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2710   star_n_le <-- {hypreal,hypnat}_le
  2711   star_n_less <-- {hypreal,hypnat}_less
  2712   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2713   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2714   star_n_abs <-- hypreal_hrabs
  2715   star_n_divide <-- hcomplex_divide
  2716 
  2717   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2718   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2719   star_of_diff <-- hypreal_of_real_diff
  2720   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2721   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2722   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2723   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2724   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2725   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2726   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2727   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2728   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2729   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2730   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2731   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2732   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2733   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2734   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2735   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2736   star_of_power <-- hypreal_of_real_power
  2737   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2738 
  2739 * Hyperreal: new method "transfer" that implements the transfer
  2740 principle of nonstandard analysis. With a subgoal that mentions
  2741 nonstandard types like "'a star", the command "apply transfer"
  2742 replaces it with an equivalent one that mentions only standard types.
  2743 To be successful, all free variables must have standard types; non-
  2744 standard variables must have explicit universal quantifiers.
  2745 
  2746 * Hyperreal: A theory of Taylor series.
  2747 
  2748 
  2749 *** HOLCF ***
  2750 
  2751 * Discontinued special version of 'constdefs' (which used to support
  2752 continuous functions) in favor of the general Pure one with full
  2753 type-inference.
  2754 
  2755 * New simplification procedure for solving continuity conditions; it
  2756 is much faster on terms with many nested lambda abstractions (cubic
  2757 instead of exponential time).
  2758 
  2759 * New syntax for domain package: selector names are now optional.
  2760 Parentheses should be omitted unless argument is lazy, for example:
  2761 
  2762   domain 'a stream = cons "'a" (lazy "'a stream")
  2763 
  2764 * New command 'fixrec' for defining recursive functions with pattern
  2765 matching; defining multiple functions with mutual recursion is also
  2766 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2767 sinr, or any data constructor defined by the domain package. The given
  2768 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2769 syntax and examples.
  2770 
  2771 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2772 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2773 but the proof obligation additionally includes an admissibility
  2774 requirement. The packages generate instances of class cpo or pcpo,
  2775 with continuity and strictness theorems for Rep and Abs.
  2776 
  2777 * HOLCF: Many theorems have been renamed according to a more standard naming
  2778 scheme (INCOMPATIBILITY):
  2779 
  2780   foo_inject:  "foo$x = foo$y ==> x = y"
  2781   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2782   foo_less:    "(foo$x << foo$y) = (x << y)"
  2783   foo_strict:  "foo$UU = UU"
  2784   foo_defined: "... ==> foo$x ~= UU"
  2785   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2786 
  2787 
  2788 *** ZF ***
  2789 
  2790 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2791 including the First Isomorphism Theorem (on quotienting by the kernel
  2792 of a homomorphism).
  2793 
  2794 * ZF/Simplifier: install second copy of type solver that actually
  2795 makes use of TC rules declared to Isar proof contexts (or locales);
  2796 the old version is still required for ML proof scripts.
  2797 
  2798 
  2799 *** Cube ***
  2800 
  2801 * Converted to Isar theory format; use locales instead of axiomatic
  2802 theories.
  2803 
  2804 
  2805 *** ML ***
  2806 
  2807 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2808 for ||>, ||>>, |>>,
  2809 
  2810 * Pure/library.ML no longer defines its own option datatype, but uses
  2811 that of the SML basis, which has constructors NONE and SOME instead of
  2812 None and Some, as well as exception Option.Option instead of OPTION.
  2813 The functions the, if_none, is_some, is_none have been adapted
  2814 accordingly, while Option.map replaces apsome.
  2815 
  2816 * Pure/library.ML: the exception LIST has been given up in favour of
  2817 the standard exceptions Empty and Subscript, as well as
  2818 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2819 superceded by the standard hd and tl functions etc.
  2820 
  2821 A number of basic list functions are no longer exported to the ML
  2822 toplevel, as they are variants of predefined functions.  The following
  2823 suggests how one can translate existing code:
  2824 
  2825     rev_append xs ys = List.revAppend (xs, ys)
  2826     nth_elem (i, xs) = List.nth (xs, i)
  2827     last_elem xs = List.last xs
  2828     flat xss = List.concat xss
  2829     seq fs = List.app fs
  2830     partition P xs = List.partition P xs
  2831     mapfilter f xs = List.mapPartial f xs
  2832 
  2833 * Pure/library.ML: several combinators for linear functional
  2834 transformations, notably reverse application and composition:
  2835 
  2836   x |> f                f #> g
  2837   (x, y) |-> f          f #-> g
  2838 
  2839 * Pure/library.ML: introduced/changed precedence of infix operators:
  2840 
  2841   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2842   infix 2 ?;
  2843   infix 3 o oo ooo oooo;
  2844   infix 4 ~~ upto downto;
  2845 
  2846 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2847 infix operators.
  2848 
  2849 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2850 fold_map support linear functional transformations and nesting.  For
  2851 example:
  2852 
  2853   fold f [x1, ..., xN] y =
  2854     y |> f x1 |> ... |> f xN
  2855 
  2856   (fold o fold) f [xs1, ..., xsN] y =
  2857     y |> fold f xs1 |> ... |> fold f xsN
  2858 
  2859   fold f [x1, ..., xN] =
  2860     f x1 #> ... #> f xN
  2861 
  2862   (fold o fold) f [xs1, ..., xsN] =
  2863     fold f xs1 #> ... #> fold f xsN
  2864 
  2865 * Pure/library.ML: the following selectors on type 'a option are
  2866 available:
  2867 
  2868   the:               'a option -> 'a  (*partial*)
  2869   these:             'a option -> 'a  where 'a = 'b list
  2870   the_default: 'a -> 'a option -> 'a
  2871   the_list:          'a option -> 'a list
  2872 
  2873 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2874 basic operations for association lists, following natural argument
  2875 order; moreover the explicit equality predicate passed here avoids
  2876 potentially expensive polymorphic runtime equality checks.
  2877 The old functions may be expressed as follows:
  2878 
  2879   assoc = uncurry (AList.lookup (op =))
  2880   assocs = these oo AList.lookup (op =)
  2881   overwrite = uncurry (AList.update (op =)) o swap
  2882 
  2883 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2884 
  2885   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2886   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2887 
  2888 replacing make_keylist and keyfilter (occassionally used)
  2889 Naive rewrites:
  2890 
  2891   make_keylist = AList.make
  2892   keyfilter = AList.find (op =)
  2893 
  2894 * eq_fst and eq_snd now take explicit equality parameter, thus
  2895   avoiding eqtypes. Naive rewrites:
  2896 
  2897     eq_fst = eq_fst (op =)
  2898     eq_snd = eq_snd (op =)
  2899 
  2900 * Removed deprecated apl and apr (rarely used).
  2901   Naive rewrites:
  2902 
  2903     apl (n, op) =>>= curry op n
  2904     apr (op, m) =>>= fn n => op (n, m)
  2905 
  2906 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2907 provides a reasonably efficient light-weight implementation of sets as
  2908 lists.
  2909 
  2910 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2911 few new operations; existing lookup and update are now curried to
  2912 follow natural argument order (for use with fold etc.);
  2913 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2914 
  2915 * Pure/General: output via the Isabelle channels of
  2916 writeln/warning/error etc. is now passed through Output.output, with a
  2917 hook for arbitrary transformations depending on the print_mode
  2918 (cf. Output.add_mode -- the first active mode that provides a output
  2919 function wins).  Already formatted output may be embedded into further
  2920 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2921 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2922 accommodate easy composition of diagnostic messages etc.  Programmers
  2923 rarely need to care about Output.output or Output.raw at all, with
  2924 some notable exceptions: Output.output is required when bypassing the
  2925 standard channels (writeln etc.), or in token translations to produce
  2926 properly formatted results; Output.raw is required when capturing
  2927 already output material that will eventually be presented to the user
  2928 a second time.  For the default print mode, both Output.output and
  2929 Output.raw have no effect.
  2930 
  2931 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2932 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2933 cumulative results are displayed at the end of a batch session.
  2934 
  2935 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2936 replaced by File.platform_path and File.shell_path (with appropriate
  2937 hooks).  This provides a clean interface for unusual systems where the
  2938 internal and external process view of file names are different.
  2939 
  2940 * Pure: more efficient orders for basic syntactic entities: added
  2941 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2942 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2943 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2944 orders now -- potential INCOMPATIBILITY for code that depends on a
  2945 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2946 Library.sort_strings on result).
  2947 
  2948 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2949 fold_types traverse types/terms from left to right, observing natural
  2950 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2951 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2952 
  2953 * Pure: name spaces have been refined, with significant changes of the
  2954 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2955 to extern(_table).  The plain name entry path is superceded by a
  2956 general 'naming' context, which also includes the 'policy' to produce
  2957 a fully qualified name and external accesses of a fully qualified
  2958 name; NameSpace.extend is superceded by context dependent
  2959 Sign.declare_name.  Several theory and proof context operations modify
  2960 the naming context.  Especially note Theory.restore_naming and
  2961 ProofContext.restore_naming to get back to a sane state; note that
  2962 Theory.add_path is no longer sufficient to recover from
  2963 Theory.absolute_path in particular.
  2964 
  2965 * Pure: new flags short_names (default false) and unique_names
  2966 (default true) for controlling output of qualified names.  If
  2967 short_names is set, names are printed unqualified.  If unique_names is
  2968 reset, the name prefix is reduced to the minimum required to achieve
  2969 the original result when interning again, even if there is an overlap
  2970 with earlier declarations.
  2971 
  2972 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2973 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2974 (useful for printing error messages).  INCOMPATIBILITY.
  2975 
  2976 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2977 Theory.theory are now identified, referring to the universal
  2978 Context.theory (see Pure/context.ML).  Actual signature and theory
  2979 content is managed as theory data.  The old code and interfaces were
  2980 spread over many files and structures; the new arrangement introduces
  2981 considerable INCOMPATIBILITY to gain more clarity:
  2982 
  2983   Context -- theory management operations (name, identity, inclusion,
  2984     parents, ancestors, merge, etc.), plus generic theory data;
  2985 
  2986   Sign -- logical signature and syntax operations (declaring consts,
  2987     types, etc.), plus certify/read for common entities;
  2988 
  2989   Theory -- logical theory operations (stating axioms, definitions,
  2990     oracles), plus a copy of logical signature operations (consts,
  2991     types, etc.); also a few basic management operations (Theory.copy,
  2992     Theory.merge, etc.)
  2993 
  2994 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2995 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2996 for convenience -- they merely return the theory.
  2997 
  2998 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2999 
  3000 * Pure: the Isar proof context type is already defined early in Pure
  3001 as Context.proof (note that ProofContext.context and Proof.context are
  3002 aliases, where the latter is the preferred name).  This enables other
  3003 Isabelle components to refer to that type even before Isar is present.
  3004 
  3005 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3006 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3007 any of these kinds.  For example, Sign.intern typeK is now
  3008 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3009 Theory.hide_types.  Also note that former
  3010 Theory.hide_classes/types/consts are now
  3011 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3012 internalize their arguments!  INCOMPATIBILITY.
  3013 
  3014 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3015 datatype thmref (with constructors Name and NameSelection) instead of
  3016 plain string -- INCOMPATIBILITY;
  3017 
  3018 * Pure: cases produced by proof methods specify options, where NONE
  3019 means to remove case bindings -- INCOMPATIBILITY in
  3020 (RAW_)METHOD_CASES.
  3021 
  3022 * Pure: the following operations retrieve axioms or theorems from a
  3023 theory node or theory hierarchy, respectively:
  3024 
  3025   Theory.axioms_of: theory -> (string * term) list
  3026   Theory.all_axioms_of: theory -> (string * term) list
  3027   PureThy.thms_of: theory -> (string * thm) list
  3028   PureThy.all_thms_of: theory -> (string * thm) list
  3029 
  3030 * Pure: print_tac now outputs the goal through the trace channel.
  3031 
  3032 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3033 Reference Toplevel.debug (default false) controls detailed printing
  3034 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3035 controls execution profiling -- set to 1 for time and 2 for space
  3036 (both increase the runtime).
  3037 
  3038 * Isar session: The initial use of ROOT.ML is now always timed,
  3039 i.e. the log will show the actual process times, in contrast to the
  3040 elapsed wall-clock time that the outer shell wrapper produces.
  3041 
  3042 * Simplifier: improved handling of bound variables (nameless
  3043 representation, avoid allocating new strings).  Simprocs that invoke
  3044 the Simplifier recursively should use Simplifier.inherit_bounds to
  3045 avoid local name clashes.  Failure to do so produces warnings
  3046 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3047 for further details.
  3048 
  3049 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3050 bindings for all theorems stored within a given theory; this may help
  3051 in porting non-Isar theories to Isar ones, while keeping ML proof
  3052 scripts for the time being.
  3053 
  3054 * ML operator HTML.with_charset specifies the charset begin used for
  3055 generated HTML files.  For example:
  3056 
  3057   HTML.with_charset "utf-8" use_thy "Hebrew";
  3058   HTML.with_charset "utf-8" use_thy "Chinese";
  3059 
  3060 
  3061 *** System ***
  3062 
  3063 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3064 isabelle, isatool etc.).
  3065 
  3066 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3067 isatool doc, isatool mkdir, display_drafts etc.).
  3068 
  3069 * isatool usedir: option -f allows specification of the ML file to be
  3070 used by Isabelle; default is ROOT.ML.
  3071 
  3072 * New isatool version outputs the version identifier of the Isabelle
  3073 distribution being used.
  3074 
  3075 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3076 (containing Boolean satisfiability problems) into Isabelle/HOL
  3077 theories.
  3078 
  3079 
  3080 
  3081 New in Isabelle2004 (April 2004)
  3082 --------------------------------
  3083 
  3084 *** General ***
  3085 
  3086 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3087   Replaces linorder.ML.
  3088 
  3089 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3090   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3091   (\<a>...\<z>), are now considered normal letters, and can therefore
  3092   be used anywhere where an ASCII letter (a...zA...Z) has until
  3093   now. COMPATIBILITY: This obviously changes the parsing of some
  3094   terms, especially where a symbol has been used as a binder, say
  3095   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3096   as an identifier.  Fix it by inserting a space around former
  3097   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3098   existing theory and ML files.
  3099 
  3100 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3101 
  3102 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3103   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3104   a normal (but invisible) letter. For multiple letter subscripts repeat
  3105   \<^isub> like this: x\<^isub>1\<^isub>2.
  3106 
  3107 * Pure: There are now sub-/superscripts that can span more than one
  3108   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3109   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3110   superscript. The new control characters are not identifier parts.
  3111 
  3112 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3113   content of "..." to the latex file instead of \isacntrl... . The "..."
  3114   may consist of any printable characters excluding the end bracket >.
  3115 
  3116 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3117   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3118   declare constants "final", which prevents their being given a definition
  3119   later.  It is useful for constants whose behaviour is fixed axiomatically
  3120   rather than definitionally, such as the meta-logic connectives.
  3121 
  3122 * Pure: 'instance' now handles general arities with general sorts
  3123   (i.e. intersections of classes),
  3124 
  3125 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3126   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3127   It can be changed to alter the colors/layout of generated pages.
  3128 
  3129 
  3130 *** Isar ***
  3131 
  3132 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3133   cut_tac, subgoal_tac and thin_tac:
  3134   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3135     locales are no longer forced to write Isar proof scripts.
  3136     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3137     emulations.
  3138   - INCOMPATIBILITY: names of variables to be instantiated may no
  3139     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3140     This is consistent with the instantiation attribute "where".
  3141 
  3142 * Attributes "where" and "of":
  3143   - Now take type variables of instantiated theorem into account when reading
  3144     the instantiation string.  This fixes a bug that caused instantiated
  3145     theorems to have too special types in some circumstances.
  3146   - "where" permits explicit instantiations of type variables.
  3147 
  3148 * Calculation commands "moreover" and "also" no longer interfere with
  3149   current facts ("this"), admitting arbitrary combinations with "then"
  3150   and derived forms.
  3151 
  3152 * Locales:
  3153   - Goal statements involving the context element "includes" no longer
  3154     generate theorems with internal delta predicates (those ending on
  3155     "_axioms") in the premise.
  3156     Resolve particular premise with <locale>.intro to obtain old form.
  3157   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3158     specification and "includes" elements in goal statement.
  3159   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3160     [intro?] and [elim?] (respectively) by default.
  3161   - Experimental command for instantiation of locales in proof contexts:
  3162         instantiate <label>[<attrs>]: <loc>
  3163     Instantiates locale <loc> and adds all its theorems to the current context
  3164     taking into account their attributes.  Label and attrs are optional
  3165     modifiers, like in theorem declarations.  If present, names of
  3166     instantiated theorems are qualified with <label>, and the attributes
  3167     <attrs> are applied after any attributes these theorems might have already.
  3168       If the locale has assumptions, a chained fact of the form
  3169     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3170     are derived.  The command does not support old-style locales declared
  3171     with "locale (open)".
  3172       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3173 
  3174 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3175   (Isar) contexts.
  3176 
  3177 
  3178 *** HOL ***
  3179 
  3180 * Proof import: new image HOL4 contains the imported library from
  3181   the HOL4 system with about 2500 theorems. It is imported by
  3182   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3183   can be used like any other Isabelle image.  See
  3184   HOL/Import/HOL/README for more information.
  3185 
  3186 * Simplifier:
  3187   - Much improved handling of linear and partial orders.
  3188     Reasoners for linear and partial orders are set up for type classes
  3189     "linorder" and "order" respectively, and are added to the default simpset
  3190     as solvers.  This means that the simplifier can build transitivity chains
  3191     to solve goals from the assumptions.
  3192   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3193     of blast or auto after simplification become unnecessary because the goal
  3194     is solved by simplification already.
  3195 
  3196 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3197     all proved in axiomatic type classes for semirings, rings and fields.
  3198 
  3199 * Numerics:
  3200   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3201     now formalized using the Ring_and_Field theory mentioned above.
  3202   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3203     than before, because now they are set up once in a generic manner.
  3204   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3205     Look for the general versions in Ring_and_Field (and Power if they concern
  3206     exponentiation).
  3207 
  3208 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3209 
  3210 * Records:
  3211   - Record types are now by default printed with their type abbreviation
  3212     instead of the list of all field types. This can be configured via
  3213     the reference "print_record_type_abbr".
  3214   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3215     (not enabled by default).
  3216   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3217     EX x. x = sel r to True (not enabled by default).
  3218   - Tactic "record_split_simp_tac" to split and simplify records added.
  3219 
  3220 * 'specification' command added, allowing for definition by
  3221   specification.  There is also an 'ax_specification' command that
  3222   introduces the new constants axiomatically.
  3223 
  3224 * arith(_tac) is now able to generate counterexamples for reals as well.
  3225 
  3226 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3227 
  3228 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3229   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3230 
  3231 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3232   matrix theory to linear programming.
  3233 
  3234 * Unions and Intersections:
  3235   The latex output syntax of UN and INT has been changed
  3236   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3237   i.e. the index formulae has become a subscript.
  3238   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3239 
  3240 * Unions and Intersections over Intervals:
  3241   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3242   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3243   like in normal math, and corresponding versions for < and for intersection.
  3244 
  3245 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3246   lexicographic dictonary ordering has been added as "lexord".
  3247 
  3248 * ML: the legacy theory structures Int and List have been removed. They had
  3249   conflicted with ML Basis Library structures having the same names.
  3250 
  3251 * 'refute' command added to search for (finite) countermodels.  Only works
  3252   for a fragment of HOL.  The installation of an external SAT solver is
  3253   highly recommended.  See "HOL/Refute.thy" for details.
  3254 
  3255 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3256   formulae under an assignment of free variables to random values.
  3257   In contrast to 'refute', it can deal with inductive datatypes,
  3258   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3259   for examples.
  3260 
  3261 
  3262 *** HOLCF ***
  3263 
  3264 * Streams now come with concatenation and are part of the HOLCF image
  3265 
  3266 
  3267 
  3268 New in Isabelle2003 (May 2003)
  3269 ------------------------------
  3270 
  3271 *** General ***
  3272 
  3273 * Provers/simplifier:
  3274 
  3275   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3276     Assumptions are now subject to complete mutual simplification,
  3277     not just from left to right. The simplifier now preserves
  3278     the order of assumptions.
  3279 
  3280     Potential INCOMPATIBILITY:
  3281 
  3282     -- simp sometimes diverges where the old version did
  3283        not, e.g. invoking simp on the goal
  3284 
  3285         [| P (f x); y = x; f x = f y |] ==> Q
  3286 
  3287        now gives rise to the infinite reduction sequence
  3288 
  3289         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3290 
  3291        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3292        kind of problem.
  3293 
  3294     -- Tactics combining classical reasoner and simplification (such as auto)
  3295        are also affected by this change, because many of them rely on
  3296        simp. They may sometimes diverge as well or yield a different numbers
  3297        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3298        in case of problems. Sometimes subsequent calls to the classical
  3299        reasoner will fail because a preceeding call to the simplifier too
  3300        eagerly simplified the goal, e.g. deleted redundant premises.
  3301 
  3302   - The simplifier trace now shows the names of the applied rewrite rules
  3303 
  3304   - You can limit the number of recursive invocations of the simplifier
  3305     during conditional rewriting (where the simplifie tries to solve the
  3306     conditions before applying the rewrite rule):
  3307     ML "simp_depth_limit := n"
  3308     where n is an integer. Thus you can force termination where previously
  3309     the simplifier would diverge.
  3310 
  3311   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3312 
  3313   - No longer aborts on failed congruence proof.  Instead, the
  3314     congruence is ignored.
  3315 
  3316 * Pure: New generic framework for extracting programs from constructive
  3317   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3318   as HOL/Extraction for some case studies.
  3319 
  3320 * Pure: The main goal of the proof state is no longer shown by default, only
  3321 the subgoals. This behaviour is controlled by a new flag.
  3322    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3323 (ML: Proof.show_main_goal).
  3324 
  3325 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3326 rules whose conclusion matches subgoal 1:
  3327       PG menu: Isabelle/Isar -> Show me -> matching rules
  3328 The rules are ordered by how closely they match the subgoal.
  3329 In particular, rules that solve a subgoal outright are displayed first
  3330 (or rather last, the way they are printed).
  3331 (ML: ProofGeneral.print_intros())
  3332 
  3333 * Pure: New flag trace_unify_fail causes unification to print
  3334 diagnostic information (PG: in trace buffer) when it fails. This is
  3335 useful for figuring out why single step proofs like rule, erule or
  3336 assumption failed.
  3337 
  3338 * Pure: Locale specifications now produce predicate definitions
  3339 according to the body of text (covering assumptions modulo local
  3340 definitions); predicate "loc_axioms" covers newly introduced text,
  3341 while "loc" is cumulative wrt. all included locale expressions; the
  3342 latter view is presented only on export into the global theory
  3343 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3344 on the old view without predicates;
  3345 
  3346 * Pure: predefined locales "var" and "struct" are useful for sharing
  3347 parameters (as in CASL, for example); just specify something like
  3348 ``var x + var y + struct M'' as import;
  3349 
  3350 * Pure: improved thms_containing: proper indexing of facts instead of
  3351 raw theorems; check validity of results wrt. current name space;
  3352 include local facts of proof configuration (also covers active
  3353 locales), cover fixed variables in index; may use "_" in term
  3354 specification; an optional limit for the number of printed facts may
  3355 be given (the default is 40);
  3356 
  3357 * Pure: disallow duplicate fact bindings within new-style theory files
  3358 (batch-mode only);
  3359 
  3360 * Provers: improved induct method: assumptions introduced by case
  3361 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3362 the goal statement); "foo" still refers to all facts collectively;
  3363 
  3364 * Provers: the function blast.overloaded has been removed: all constants
  3365 are regarded as potentially overloaded, which improves robustness in exchange
  3366 for slight decrease in efficiency;
  3367 
  3368 * Provers/linorder: New generic prover for transitivity reasoning over
  3369 linear orders.  Note: this prover is not efficient!
  3370 
  3371 * Isar: preview of problems to finish 'show' now produce an error
  3372 rather than just a warning (in interactive mode);
  3373 
  3374 
  3375 *** HOL ***
  3376 
  3377 * arith(_tac)
  3378 
  3379  - Produces a counter example if it cannot prove a goal.
  3380    Note that the counter example may be spurious if the goal is not a formula
  3381    of quantifier-free linear arithmetic.
  3382    In ProofGeneral the counter example appears in the trace buffer.
  3383 
  3384  - Knows about div k and mod k where k is a numeral of type nat or int.
  3385 
  3386  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3387    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3388    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3389 
  3390 * simp's arithmetic capabilities have been enhanced a bit: it now
  3391 takes ~= in premises into account (by performing a case split);
  3392 
  3393 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3394 are distributed over a sum of terms;
  3395 
  3396 * New tactic "trans_tac" and method "trans" instantiate
  3397 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3398 "<=", "<" and "=").
  3399 
  3400 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3401 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3402 
  3403 * 'typedef' command has new option "open" to suppress the set
  3404 definition;
  3405 
  3406 * functions Min and Max on finite sets have been introduced (theory
  3407 Finite_Set);
  3408 
  3409 * attribute [symmetric] now works for relations as well; it turns
  3410 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3411 
  3412 * induct over a !!-quantified statement (say !!x1..xn):
  3413   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3414 
  3415 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3416 %x. None. Warning: empty_def now refers to the previously hidden definition
  3417 of the empty set.
  3418 
  3419 * Algebra: formalization of classical algebra.  Intended as base for
  3420 any algebraic development in Isabelle.  Currently covers group theory
  3421 (up to Sylow's theorem) and ring theory (Universal Property of
  3422 Univariate Polynomials).  Contributions welcome;
  3423 
  3424 * GroupTheory: deleted, since its material has been moved to Algebra;
  3425 
  3426 * Complex: new directory of the complex numbers with numeric constants,
  3427 nonstandard complex numbers, and some complex analysis, standard and
  3428 nonstandard (Jacques Fleuriot);
  3429 
  3430 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3431 
  3432 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3433 Fleuriot);
  3434 
  3435 * Real/HahnBanach: updated and adapted to locales;
  3436 
  3437 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3438 Gray and Kramer);
  3439 
  3440 * UNITY: added the Meier-Sanders theory of progress sets;
  3441 
  3442 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3443 as abstract algorithms, instantiated to the JVM;
  3444 
  3445 * Bali: Java source language formalization. Type system, operational
  3446 semantics, axiomatic semantics. Supported language features:
  3447 classes, interfaces, objects,virtual methods, static methods,
  3448 static/instance fields, arrays, access modifiers, definite
  3449 assignment, exceptions.
  3450 
  3451 
  3452 *** ZF ***
  3453 
  3454 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3455 universe, etc.);
  3456 
  3457 * Main ZF: virtually all theories converted to new-style format;
  3458 
  3459 
  3460 *** ML ***
  3461 
  3462 * Pure: Tactic.prove provides sane interface for internal proofs;
  3463 omits the infamous "standard" operation, so this is more appropriate
  3464 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3465 
  3466 * Pure: improved error reporting of simprocs;
  3467 
  3468 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3469 up simprocs;
  3470 
  3471 
  3472 *** Document preparation ***
  3473 
  3474 * uses \par instead of \\ for line breaks in theory text. This may
  3475 shift some page breaks in large documents. To get the old behaviour
  3476 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3477 
  3478 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3479 other packages
  3480 
  3481 * \<euro> now needs package babel/greek instead of marvosym (which
  3482 broke \Rightarrow)
  3483 
  3484 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3485 textcomp package)
  3486 
  3487 
  3488 
  3489 New in Isabelle2002 (March 2002)
  3490 --------------------------------
  3491 
  3492 *** Document preparation ***
  3493 
  3494 * greatly simplified document preparation setup, including more
  3495 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3496 instructive isatool mkdir; users should basically be able to get
  3497 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3498 users may run a separate document processing stage manually like this:
  3499 "isatool usedir -D output HOL Test && isatool document Test/output";
  3500 
  3501 * theory dependency graph may now be incorporated into documents;
  3502 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3503 with \includegraphics of LaTeX;
  3504 
  3505 * proper spacing of consecutive markup elements, especially text
  3506 blocks after section headings;
  3507 
  3508 * support bold style (for single symbols only), input syntax is like
  3509 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3510 
  3511 * \<bullet> is now output as bold \cdot by default, which looks much
  3512 better in printed text;
  3513 
  3514 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3515 note that these symbols are currently unavailable in Proof General /
  3516 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3517 
  3518 * isatool latex no longer depends on changed TEXINPUTS, instead
  3519 isatool document copies the Isabelle style files to the target
  3520 location;
  3521 
  3522 
  3523 *** Isar ***
  3524 
  3525 * Pure/Provers: improved proof by cases and induction;
  3526   - 'case' command admits impromptu naming of parameters (such as
  3527     "case (Suc n)");
  3528   - 'induct' method divinates rule instantiation from the inductive
  3529     claim; no longer requires excessive ?P bindings for proper
  3530     instantiation of cases;
  3531   - 'induct' method properly enumerates all possibilities of set/type
  3532     rules; as a consequence facts may be also passed through *type*
  3533     rules without further ado;
  3534   - 'induct' method now derives symbolic cases from the *rulified*
  3535     rule (before it used to rulify cases stemming from the internal
  3536     atomized version); this means that the context of a non-atomic
  3537     statement becomes is included in the hypothesis, avoiding the
  3538     slightly cumbersome show "PROP ?case" form;
  3539   - 'induct' may now use elim-style induction rules without chaining
  3540     facts, using ``missing'' premises from the goal state; this allows
  3541     rules stemming from inductive sets to be applied in unstructured
  3542     scripts, while still benefitting from proper handling of non-atomic
  3543     statements; NB: major inductive premises need to be put first, all
  3544     the rest of the goal is passed through the induction;
  3545   - 'induct' proper support for mutual induction involving non-atomic
  3546     rule statements (uses the new concept of simultaneous goals, see
  3547     below);
  3548   - append all possible rule selections, but only use the first
  3549     success (no backtracking);
  3550   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3551   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3552   - added 'print_induct_rules' (covered by help item in recent Proof
  3553     General versions);
  3554   - moved induct/cases attributes to Pure, methods to Provers;
  3555   - generic method setup instantiated for FOL and HOL;
  3556 
  3557 * Pure: support multiple simultaneous goal statements, for example
  3558 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3559 meta-level mechanism, this acts as if several individual goals had
  3560 been stated separately; in particular common proof methods need to be
  3561 repeated in order to cover all claims; note that a single elimination
  3562 step is *not* sufficient to establish the two conjunctions, so this
  3563 fails:
  3564 
  3565   assume "A & B" then have A and B ..   (*".." fails*)
  3566 
  3567 better use "obtain" in situations as above; alternative refer to
  3568 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  3569 
  3570 * Pure: proper integration with ``locales''; unlike the original
  3571 version by Florian Kammller, Isar locales package high-level proof
  3572 contexts rather than raw logical ones (e.g. we admit to include
  3573 attributes everywhere); operations on locales include merge and
  3574 rename; support for implicit arguments (``structures''); simultaneous
  3575 type-inference over imports and text; see also HOL/ex/Locales.thy for
  3576 some examples;
  3577 
  3578 * Pure: the following commands have been ``localized'', supporting a
  3579 target locale specification "(in name)": 'lemma', 'theorem',
  3580 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  3581 stored both within the locale and at the theory level (exported and
  3582 qualified by the locale name);
  3583 
  3584 * Pure: theory goals may now be specified in ``long'' form, with
  3585 ad-hoc contexts consisting of arbitrary locale elements. for example
  3586 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  3587 definitions may be given, too); the result is a meta-level rule with
  3588 the context elements being discharged in the obvious way;
  3589 
  3590 * Pure: new proof command 'using' allows to augment currently used
  3591 facts after a goal statement ('using' is syntactically analogous to
  3592 'apply', but acts on the goal's facts only); this allows chained facts
  3593 to be separated into parts given before and after a claim, as in
  3594 ``from a and b have C using d and e <proof>'';
  3595 
  3596 * Pure: renamed "antecedent" case to "rule_context";
  3597 
  3598 * Pure: new 'judgment' command records explicit information about the
  3599 object-logic embedding (used by several tools internally); no longer
  3600 use hard-wired "Trueprop";
  3601 
  3602 * Pure: added 'corollary' command;
  3603 
  3604 * Pure: fixed 'token_translation' command;
  3605 
  3606 * Pure: removed obsolete 'exported' attribute;
  3607 
  3608 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3609 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3610 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3611 
  3612 * Pure: method 'atomize' presents local goal premises as object-level
  3613 statements (atomic meta-level propositions); setup controlled via
  3614 rewrite rules declarations of 'atomize' attribute; example
  3615 application: 'induct' method with proper rule statements in improper
  3616 proof *scripts*;
  3617 
  3618 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3619 now consider the syntactic context of assumptions, giving a better
  3620 chance to get type-inference of the arguments right (this is
  3621 especially important for locales);
  3622 
  3623 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3624 mode;
  3625 
  3626 * Pure/obtain: the formal conclusion "thesis", being marked as
  3627 ``internal'', may no longer be reference directly in the text;
  3628 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3629 situations;
  3630 
  3631 * Pure: generic 'sym' attribute which declares a rule both as pure
  3632 'elim?' and for the 'symmetric' operation;
  3633 
  3634 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3635 text; the fixed correlation with particular command syntax has been
  3636 discontinued;
  3637 
  3638 * Pure: new method 'rules' is particularly well-suited for proof
  3639 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3640 but often produces more compact proof terms with less detours;
  3641 
  3642 * Pure/Provers/classical: simplified integration with pure rule
  3643 attributes and methods; the classical "intro?/elim?/dest?"
  3644 declarations coincide with the pure ones; the "rule" method no longer
  3645 includes classically swapped intros; "intro" and "elim" methods no
  3646 longer pick rules from the context; also got rid of ML declarations
  3647 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3648 INCOMPATIBILITY;
  3649 
  3650 * Provers/classical: attribute 'swapped' produces classical inversions
  3651 of introduction rules;
  3652 
  3653 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3654 rules instead of full simplifier context; 'iff' attribute handles
  3655 conditional rules;
  3656 
  3657 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3658 
  3659 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3660 "(permissive)" option to recover old behavior;
  3661 
  3662 * HOL: 'inductive' no longer features separate (collective) attributes
  3663 for 'intros' (was found too confusing);
  3664 
  3665 * HOL: properly declared induction rules less_induct and
  3666 wf_induct_rule;
  3667 
  3668 
  3669 *** HOL ***
  3670 
  3671 * HOL: moved over to sane numeral syntax; the new policy is as
  3672 follows:
  3673 
  3674   - 0 and 1 are polymorphic constants, which are defined on any
  3675   numeric type (nat, int, real etc.);
  3676 
  3677   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3678   binary representation internally;
  3679 
  3680   - type nat has special constructor Suc, and generally prefers Suc 0
  3681   over 1::nat and Suc (Suc 0) over 2::nat;
  3682 
  3683 This change may cause significant problems of INCOMPATIBILITY; here
  3684 are some hints on converting existing sources:
  3685 
  3686   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3687   entities, so expressions involving "-" (unary or binary minus) need
  3688   to be spaced properly;
  3689 
  3690   - existing occurrences of "1" may need to be constraint "1::nat" or
  3691   even replaced by Suc 0; similar for old "2";
  3692 
  3693   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3694 
  3695   - remove all special provisions on numerals in proofs;
  3696 
  3697 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3698 representation (depends on bin_arith_simps in the default context);
  3699 
  3700 * HOL: symbolic syntax for x^2 (numeral 2);
  3701 
  3702 * HOL: the class of all HOL types is now called "type" rather than
  3703 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3704 in axclass/classes, instance/arities, and (usually rare) occurrences
  3705 in typings (of consts etc.); internally the class is called
  3706 "HOL.type", ML programs should refer to HOLogic.typeS;
  3707 
  3708 * HOL/record package improvements:
  3709   - new derived operations "fields" to build a partial record section,
  3710     "extend" to promote a fixed record to a record scheme, and
  3711     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3712     declared as simp by default;
  3713   - shared operations ("more", "fields", etc.) now need to be always
  3714     qualified) --- potential INCOMPATIBILITY;
  3715   - removed "make_scheme" operations (use "make" with "extend") --
  3716     INCOMPATIBILITY;
  3717   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3718   - provides cases/induct rules for use with corresponding Isar
  3719     methods (for concrete records, record schemes, concrete more
  3720     parts, and schematic more parts -- in that order);
  3721   - internal definitions directly based on a light-weight abstract
  3722     theory of product types over typedef rather than datatype;
  3723 
  3724 * HOL: generic code generator for generating executable ML code from
  3725 specifications; specific support for HOL constructs such as inductive
  3726 datatypes and sets, as well as recursive functions; can be invoked
  3727 via 'generate_code' theory section;
  3728 
  3729 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3730 
  3731 * HOL: consolidated and renamed several theories.  In particular:
  3732         Ord.thy has been absorbed into HOL.thy
  3733         String.thy has been absorbed into List.thy
  3734 
  3735 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3736 (beware of argument permutation!);
  3737 
  3738 * HOL: linorder_less_split superseded by linorder_cases;
  3739 
  3740 * HOL/List: "nodups" renamed to "distinct";
  3741 
  3742 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3743 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3744   - Ex_def has changed, now need to use some_eq_ex
  3745 
  3746 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3747 in this (rare) case use:
  3748 
  3749   delSWrapper "split_all_tac"
  3750   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3751 
  3752 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3753 MAY FAIL;
  3754 
  3755 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3756 Isabelle's type classes, ^ on functions and relations has too general
  3757 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3758 necessary to attach explicit type constraints;
  3759 
  3760 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3761 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3762 renamed accordingly (eg "compI" -> "rel_compI").
  3763 
  3764 * HOL: syntax translations now work properly with numerals and records
  3765 expressions;
  3766 
  3767 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3768 of "lam" -- INCOMPATIBILITY;
  3769 
  3770 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3771 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3772 renamed "Product_Type.unit";
  3773 
  3774 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3775 
  3776 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3777 the "cases" method);
  3778 
  3779 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3780 Florian Kammller);
  3781 
  3782 * HOL/IMP: updated and converted to new-style theory format; several
  3783 parts turned into readable document, with proper Isar proof texts and
  3784 some explanations (by Gerwin Klein);
  3785 
  3786 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3787 
  3788 * HOL-Hyperreal is now a logic image;
  3789 
  3790 
  3791 *** HOLCF ***
  3792 
  3793 * Isar: consts/constdefs supports mixfix syntax for continuous
  3794 operations;
  3795 
  3796 * Isar: domain package adapted to new-style theory format, e.g. see
  3797 HOLCF/ex/Dnat.thy;
  3798 
  3799 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3800 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3801 lift.induct_tac, always use UU instead of Undef;
  3802 
  3803 * HOLCF/IMP: updated and converted to new-style theory;
  3804 
  3805 
  3806 *** ZF ***
  3807 
  3808 * Isar: proper integration of logic-specific tools and packages,
  3809 including theory commands '(co)inductive', '(co)datatype',
  3810 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3811 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3812 
  3813 * theory Main no longer includes AC; for the Axiom of Choice, base
  3814 your theory on Main_ZFC;
  3815 
  3816 * the integer library now covers quotients and remainders, with many
  3817 laws relating division to addition, multiplication, etc.;
  3818 
  3819 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3820 typeless version of the formalism;
  3821 
  3822 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3823 format;
  3824 
  3825 * ZF/Induct: new directory for examples of inductive definitions,
  3826 including theory Multiset for multiset orderings; converted to
  3827 new-style theory format;
  3828 
  3829 * ZF: many new theorems about lists, ordinals, etc.;
  3830 
  3831 
  3832 *** General ***
  3833 
  3834 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3835 variable proof controls level of detail: 0 = no proofs (only oracle
  3836 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3837 also ref manual for further ML interfaces;
  3838 
  3839 * Pure/axclass: removed obsolete ML interface
  3840 goal_subclass/goal_arity;
  3841 
  3842 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3843 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3844 separate tokens, so expressions involving minus need to be spaced
  3845 properly;
  3846 
  3847 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3848 rather than "infixl" or "infixr";
  3849 
  3850 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3851 sort constraint specifications in type inference; e.g. "x::_::foo"
  3852 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3853 type variable);
  3854 
  3855 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3856 control output of nested => (types); the default behavior is
  3857 "type_brackets";
  3858 
  3859 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3860 tokens into AST constants;
  3861 
  3862 * Pure/syntax: prefer later declarations of translations and print
  3863 translation functions; potential INCOMPATIBILITY: need to reverse
  3864 multiple declarations for same syntax element constant;
  3865 
  3866 * Pure/show_hyps reset by default (in accordance to existing Isar
  3867 practice);
  3868 
  3869 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3870 addSafter;
  3871 
  3872 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3873 as well;
  3874 
  3875 * system: tested support for MacOS X; should be able to get Isabelle +
  3876 Proof General to work in a plain Terminal after installing Poly/ML
  3877 (e.g. from the Isabelle distribution area) and GNU bash alone
  3878 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3879 support requires further installations, e.g. from
  3880 http://fink.sourceforge.net/);
  3881 
  3882 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3883 
  3884 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3885 of 40 MB), cf. ML_OPTIONS;
  3886 
  3887 * system: Proof General keywords specification is now part of the
  3888 Isabelle distribution (see etc/isar-keywords.el);
  3889 
  3890 * system: support for persistent Proof General sessions (refrain from
  3891 outdating all loaded theories on startup); user may create writable
  3892 logic images like this: ``isabelle -q HOL Test'';
  3893 
  3894 * system: smart selection of Isabelle process versus Isabelle
  3895 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3896 run both "isabelle" and "Isabelle" even if file names are badly
  3897 damaged (executable inspects the case of the first letter of its own
  3898 name); added separate "isabelle-process" and "isabelle-interface";
  3899 
  3900 * system: refrain from any attempt at filtering input streams; no
  3901 longer support ``8bit'' encoding of old isabelle font, instead proper
  3902 iso-latin characters may now be used; the related isatools
  3903 "symbolinput" and "nonascii" have disappeared as well;
  3904 
  3905 * system: removed old "xterm" interface (the print modes "xterm" and
  3906 "xterm_color" are still available for direct use in a suitable
  3907 terminal);
  3908 
  3909 
  3910 
  3911 New in Isabelle99-2 (February 2001)
  3912 -----------------------------------
  3913 
  3914 *** Overview of INCOMPATIBILITIES ***
  3915 
  3916 * HOL: please note that theories in the Library and elsewhere often use the
  3917 new-style (Isar) format; to refer to their theorems in an ML script you must
  3918 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3919 
  3920 * HOL: inductive package no longer splits induction rule aggressively,
  3921 but only as far as specified by the introductions given; the old
  3922 format may be recovered via ML function complete_split_rule or attribute
  3923 'split_rule (complete)';
  3924 
  3925 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3926 gfp_Tarski to gfp_unfold;
  3927 
  3928 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3929 
  3930 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3931 relation); infix "^^" has been renamed "``"; infix "``" has been
  3932 renamed "`"; "univalent" has been renamed "single_valued";
  3933 
  3934 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3935 operation;
  3936 
  3937 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3938 
  3939 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3940 
  3941 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3942 consequence, it is no longer monotonic wrt. the local goal context
  3943 (which is now passed through the inductive cases);
  3944 
  3945 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3946 \<gg> to \<ggreater>;
  3947 
  3948 
  3949 *** Document preparation ***
  3950 
  3951 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3952 available: are "it" for near math-mode best-style output, "sl" for
  3953 slanted text style, and "tt" for plain type-writer; if no
  3954 \isabellestyle command is given, output is according to slanted
  3955 type-writer);
  3956 
  3957 * support sub/super scripts (for single symbols only), input syntax is
  3958 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3959 
  3960 * some more standard symbols; see Appendix A of the system manual for
  3961 the complete list of symbols defined in isabellesym.sty;
  3962 
  3963 * improved isabelle style files; more abstract symbol implementation
  3964 (should now use \isamath{...} and \isatext{...} in custom symbol
  3965 definitions);
  3966 
  3967 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3968 state; Note that presentation of goal states does not conform to
  3969 actual human-readable proof documents.  Please do not include goal
  3970 states into document output unless you really know what you are doing!
  3971 
  3972 * proper indentation of antiquoted output with proportional LaTeX
  3973 fonts;
  3974 
  3975 * no_document ML operator temporarily disables LaTeX document
  3976 generation;
  3977 
  3978 * isatool unsymbolize tunes sources for plain ASCII communication;
  3979 
  3980 
  3981 *** Isar ***
  3982 
  3983 * Pure: Isar now suffers initial goal statements to contain unbound
  3984 schematic variables (this does not conform to actual readable proof
  3985 documents, due to unpredictable outcome and non-compositional proof
  3986 checking); users who know what they are doing may use schematic goals
  3987 for Prolog-style synthesis of proven results;
  3988 
  3989 * Pure: assumption method (an implicit finishing) now handles actual
  3990 rules as well;
  3991 
  3992 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3993 initial goal, declare "that" only as Pure intro (only for single
  3994 steps); the "that" rule assumption may now be involved in implicit
  3995 finishing, thus ".." becomes a feasible for trivial obtains;
  3996 
  3997 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3998 instance proofs may be performed by "..";
  3999 
  4000 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4001 statements as well;
  4002 
  4003 * Pure: more robust selection of calculational rules;
  4004 
  4005 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4006 rule (as well as the assumption rule);
  4007 
  4008 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4009 lemmas, using the graph browser tool;
  4010 
  4011 * Pure: predict failure of "show" in interactive mode;
  4012 
  4013 * Pure: 'thms_containing' now takes actual terms as arguments;
  4014 
  4015 * HOL: improved method 'induct' --- now handles non-atomic goals
  4016 (potential INCOMPATIBILITY); tuned error handling;
  4017 
  4018 * HOL: cases and induct rules now provide explicit hints about the
  4019 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4020 any remaining facts are inserted into the goal verbatim;
  4021 
  4022 * HOL: local contexts (aka cases) may now contain term bindings as
  4023 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4024 the result to be shown in each case;
  4025 
  4026 * HOL: added 'recdef_tc' command;
  4027 
  4028 * isatool convert assists in eliminating legacy ML scripts;
  4029 
  4030 
  4031 *** HOL ***
  4032 
  4033 * HOL/Library: a collection of generic theories to be used together
  4034 with main HOL; the theory loader path already includes this directory
  4035 by default; the following existing theories have been moved here:
  4036 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4037 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4038 
  4039 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4040 modelling and verification task performed in Isabelle/HOL +
  4041 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4042 
  4043 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4044 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4045 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4046 'domain', this makes the theory consistent with mathematical
  4047 literature;
  4048 
  4049 * HOL basics: added overloaded operations "inverse" and "divide"
  4050 (infix "/"), syntax for generic "abs" operation, generic summation
  4051 operator \<Sum>;
  4052 
  4053 * HOL/typedef: simplified package, provide more useful rules (see also
  4054 HOL/subset.thy);
  4055 
  4056 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4057 now expressed as a proper nested rule (old-style tactic scripts may
  4058 require atomize_strip_tac to cope with non-atomic premises);
  4059 
  4060 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4061 to "split_conv" (old name still available for compatibility);
  4062 
  4063 * HOL: improved concrete syntax for strings (e.g. allows translation
  4064 rules with string literals);
  4065 
  4066 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4067  and Fleuriot's mechanization of analysis, including the transcendental
  4068  functions for the reals;
  4069 
  4070 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4071 
  4072 
  4073 *** CTT ***
  4074 
  4075 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4076 "lam" is displayed as TWO lambda-symbols
  4077 
  4078 * CTT: theory Main now available, containing everything (that is, Bool
  4079 and Arith);
  4080 
  4081 
  4082 *** General ***
  4083 
  4084 * Pure: the Simplifier has been implemented properly as a derived rule
  4085 outside of the actual kernel (at last!); the overall performance
  4086 penalty in practical applications is about 50%, while reliability of
  4087 the Isabelle inference kernel has been greatly improved;
  4088 
  4089 * print modes "brackets" and "no_brackets" control output of nested =>
  4090 (types) and ==> (props); the default behaviour is "brackets";
  4091 
  4092 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4093 as assumptions as well;
  4094 
  4095 * system: support Poly/ML 4.0;
  4096 
  4097 * system: isatool install handles KDE version 1 or 2;
  4098 
  4099 
  4100 
  4101 New in Isabelle99-1 (October 2000)
  4102 ----------------------------------
  4103 
  4104 *** Overview of INCOMPATIBILITIES ***
  4105 
  4106 * HOL: simplification of natural numbers is much changed; to partly
  4107 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4108 issue the following ML commands:
  4109 
  4110   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4111   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4112 
  4113 * HOL: simplification no longer dives into case-expressions; this is
  4114 controlled by "t.weak_case_cong" for each datatype t;
  4115 
  4116 * HOL: nat_less_induct renamed to less_induct;
  4117 
  4118 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4119 fixsome to patch .thy and .ML sources automatically;
  4120 
  4121   select_equality  -> some_equality
  4122   select_eq_Ex     -> some_eq_ex
  4123   selectI2EX       -> someI2_ex
  4124   selectI2         -> someI2
  4125   selectI          -> someI
  4126   select1_equality -> some1_equality
  4127   Eps_sym_eq       -> some_sym_eq_trivial
  4128   Eps_eq           -> some_eq_trivial
  4129 
  4130 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4131 
  4132 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4133 instead);
  4134 
  4135 * HOL: the recursion equations generated by 'recdef' are now called
  4136 f.simps instead of f.rules;
  4137 
  4138 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4139 
  4140 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4141 sometimes be needed;
  4142 
  4143 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4144 
  4145 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4146 
  4147 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4148 product is now "<*>" instead of "Times"; the lexicographic product is
  4149 now "<*lex*>" instead of "**";
  4150 
  4151 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4152 of main HOL, but was unused); better use HOL's datatype package;
  4153 
  4154 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4155 the old syntax may be recovered as follows:
  4156 
  4157   syntax (symbols)
  4158     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4159       (infixl "\\<oplus>" 100)
  4160 
  4161 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4162 
  4163 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4164 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4165 internally;
  4166 
  4167 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4168 changed from A/r to A//r;
  4169 
  4170 * ZF: new treatment of arithmetic (nat & int) may break some old
  4171 proofs;
  4172 
  4173 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4174 rulify -> rule_format, elimify -> elim_format, ...);
  4175 
  4176 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4177 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4178 should have to change intro!! to intro? only); replaced "delrule" by
  4179 "rule del";
  4180 
  4181 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4182 
  4183 * Provers: strengthened force_tac by using new first_best_tac;
  4184 
  4185 * LaTeX document preparation: several changes of isabelle.sty (see
  4186 lib/texinputs);
  4187 
  4188 
  4189 *** Document preparation ***
  4190 
  4191 * formal comments (text blocks etc.) in new-style theories may now
  4192 contain antiquotations of thm/prop/term/typ/text to be presented
  4193 according to latex print mode; concrete syntax is like this:
  4194 @{term[show_types] "f(x) = a + x"};
  4195 
  4196 * isatool mkdir provides easy setup of Isabelle session directories,
  4197 including proper document sources;
  4198 
  4199 * generated LaTeX sources are now deleted after successful run
  4200 (isatool document -c); may retain a copy somewhere else via -D option
  4201 of isatool usedir;
  4202 
  4203 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4204 style files, achieving self-contained LaTeX sources and simplifying
  4205 LaTeX debugging;
  4206 
  4207 * old-style theories now produce (crude) LaTeX output as well;
  4208 
  4209 * browser info session directories are now self-contained (may be put
  4210 on WWW server seperately); improved graphs of nested sessions; removed
  4211 graph for 'all sessions';
  4212 
  4213 * several improvements in isabelle style files; \isabellestyle{it}
  4214 produces fake math mode output; \isamarkupheader is now \section by
  4215 default; see lib/texinputs/isabelle.sty etc.;
  4216 
  4217 
  4218 *** Isar ***
  4219 
  4220 * Isar/Pure: local results and corresponding term bindings are now
  4221 subject to Hindley-Milner polymorphism (similar to ML); this
  4222 accommodates incremental type-inference very nicely;
  4223 
  4224 * Isar/Pure: new derived language element 'obtain' supports
  4225 generalized existence reasoning;
  4226 
  4227 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4228 support accumulation of results, without applying any rules yet;
  4229 useful to collect intermediate results without explicit name
  4230 references, and for use with transitivity rules with more than 2
  4231 premises;
  4232 
  4233 * Isar/Pure: scalable support for case-analysis type proofs: new
  4234 'case' language element refers to local contexts symbolically, as
  4235 produced by certain proof methods; internally, case names are attached
  4236 to theorems as "tags";
  4237 
  4238 * Isar/Pure: theory command 'hide' removes declarations from
  4239 class/type/const name spaces;
  4240 
  4241 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4242 indicate potential overloading;
  4243 
  4244 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4245 
  4246 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4247 "{a,b,c}" instead of {a,b,c};
  4248 
  4249 * Isar/Pure now provides its own version of intro/elim/dest
  4250 attributes; useful for building new logics, but beware of confusion
  4251 with the version in Provers/classical;
  4252 
  4253 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4254 case name 'antecedent';
  4255 
  4256 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4257 to the current context is now done automatically);
  4258 
  4259 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4260 for definining proof methods in ML;
  4261 
  4262 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4263 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4264 most cases, one should have to change intro!! to intro? only);
  4265 replaced "delrule" by "rule del";
  4266 
  4267 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4268 'symmetric' attribute (the latter supercedes [RS sym]);
  4269 
  4270 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4271 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4272 well (including splits);
  4273 
  4274 * Isar/Provers: Simplifier and Classical methods now support all kind
  4275 of modifiers used in the past, including 'cong', 'iff', etc.
  4276 
  4277 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4278 of Simplifier and Classical reasoner);
  4279 
  4280 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4281 now support named cases; major packages (inductive, datatype, primrec,
  4282 recdef) support case names and properly name parameters;
  4283 
  4284 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4285 monotonicity conditions are extracted to be proven at end of
  4286 calculations;
  4287 
  4288 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4289 method anyway;
  4290 
  4291 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4292 split_if split_if_asm; datatype package provides theorems foo.splits =
  4293 foo.split foo.split_asm for each datatype;
  4294 
  4295 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4296 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4297 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4298 use "(cases (simplified))" method in proper proof texts);
  4299 
  4300 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4301 
  4302 * Isar: names of theorems etc. may be natural numbers as well;
  4303 
  4304 * Isar: 'pr' command: optional arguments for goals_limit and
  4305 ProofContext.prems_limit; no longer prints theory contexts, but only
  4306 proof states;
  4307 
  4308 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4309 additional print modes to be specified; e.g. "pr(latex)" will print
  4310 proof state according to the Isabelle LaTeX style;
  4311 
  4312 * Isar: improved support for emulating tactic scripts, including proof
  4313 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4314 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4315 (for HOL datatypes);
  4316 
  4317 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4318 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4319 'proof method scripts' have to be in depth-first order;
  4320 
  4321 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4322 
  4323 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4324 should instead use individual commands for printing items
  4325 (print_commands, print_methods etc.);
  4326 
  4327 * Isar: added 'nothing' --- the empty list of theorems;
  4328 
  4329 
  4330 *** HOL ***
  4331 
  4332 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4333 corresponding virtual machine and a specification of its bytecode
  4334 verifier and a lightweight bytecode verifier, including proofs of
  4335 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4336 Cornelia Pusch (see also the homepage of project Bali at
  4337 http://isabelle.in.tum.de/Bali/);
  4338 
  4339 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4340 Clemens Ballarin;
  4341 
  4342 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4343 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4344 Rasmussen;
  4345 
  4346 * HOL/Lattice: fundamental concepts of lattice theory and order
  4347 structures, including duals, properties of bounds versus algebraic
  4348 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4349 Theorem for complete lattices etc.; may also serve as a demonstration
  4350 for abstract algebraic reasoning using axiomatic type classes, and
  4351 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4352 
  4353 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4354 von Oheimb;
  4355 
  4356 * HOL/IMPP: extension of IMP with local variables and mutually
  4357 recursive procedures, by David von Oheimb;
  4358 
  4359 * HOL/Lambda: converted into new-style theory and document;
  4360 
  4361 * HOL/ex/Multiquote: example of multiple nested quotations and
  4362 anti-quotations -- basically a generalized version of de-Bruijn
  4363 representation; very useful in avoiding lifting of operations;
  4364 
  4365 * HOL/record: added general record equality rule to simpset; fixed
  4366 select-update simplification procedure to handle extended records as
  4367 well; admit "r" as field name;
  4368 
  4369 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4370 other numeric types and also as the identity of groups, rings, etc.;
  4371 
  4372 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4373 Types nat and int belong to this axclass;
  4374 
  4375 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4376    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4377    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4378   two terms #m*u and #n*u are replaced by #(m+n)*u
  4379     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4380   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4381     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4382 
  4383 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4384 powerful prover for predicate logic but knows nothing of clasets; see
  4385 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4386 
  4387 * HOL: new version of "case_tac" subsumes both boolean case split and
  4388 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4389 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4390 
  4391 * HOL: simplification no longer dives into case-expressions: only the
  4392 selector expression is simplified, but not the remaining arms; to
  4393 enable full simplification of case-expressions for datatype t, you may
  4394 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4395 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4396 
  4397 * HOL/recdef: the recursion equations generated by 'recdef' for
  4398 function 'f' are now called f.simps instead of f.rules; if all
  4399 termination conditions are proved automatically, these simplification
  4400 rules are added to the simpset, as in primrec; rules may be named
  4401 individually as well, resulting in a separate list of theorems for
  4402 each equation;
  4403 
  4404 * HOL/While is a new theory that provides a while-combinator. It
  4405 permits the definition of tail-recursive functions without the
  4406 provision of a termination measure. The latter is necessary once the
  4407 invariant proof rule for while is applied.
  4408 
  4409 * HOL: new (overloaded) notation for the set of elements below/above
  4410 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4411 
  4412 * HOL: theorems impI, allI, ballI bound as "strip";
  4413 
  4414 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4415 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4416 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4417 
  4418 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4419 
  4420 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4421 main HOL, but was unused);
  4422 
  4423 * HOL: fewer consts declared as global (e.g. have to refer to
  4424 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4425 
  4426 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4427 in case of overlap with user translations (e.g. judgements over
  4428 tuples); (note that the underlying logical represenation is still
  4429 bogus);
  4430 
  4431 
  4432 *** ZF ***
  4433 
  4434 * ZF: simplification automatically cancels common terms in arithmetic
  4435 expressions over nat and int;
  4436 
  4437 * ZF: new treatment of nat to minimize type-checking: all operators
  4438 coerce their operands to a natural number using the function natify,
  4439 making the algebraic laws unconditional;
  4440 
  4441 * ZF: as above, for int: operators coerce their operands to an integer
  4442 using the function intify;
  4443 
  4444 * ZF: the integer library now contains many of the usual laws for the
  4445 orderings, including $<=, and monotonicity laws for $+ and $*;
  4446 
  4447 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4448 simplification;
  4449 
  4450 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4451 to the simplifier and classical reasoner simultaneously;
  4452 
  4453 
  4454 *** General ***
  4455 
  4456 * Provers: blast_tac now handles actual object-logic rules as
  4457 assumptions; note that auto_tac uses blast_tac internally as well;
  4458 
  4459 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4460 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4461 
  4462 * Provers: delrules now handles destruct rules as well (no longer need
  4463 explicit make_elim);
  4464 
  4465 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4466   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4467 use instead the strong form,
  4468   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4469 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4470 from destruct-rules;
  4471 
  4472 * Provers: Simplifier.easy_setup provides a fast path to basic
  4473 Simplifier setup for new object-logics;
  4474 
  4475 * Pure: AST translation rules no longer require constant head on LHS;
  4476 
  4477 * Pure: improved name spaces: ambiguous output is qualified; support
  4478 for hiding of names;
  4479 
  4480 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4481 XSYMBOL_HOME; no longer need to do manual configuration in most
  4482 situations;
  4483 
  4484 * system: compression of ML heaps images may now be controlled via -c
  4485 option of isabelle and isatool usedir (currently only observed by
  4486 Poly/ML);
  4487 
  4488 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4489 useful for remote X11);
  4490 
  4491 * system: provide TAGS file for Isabelle sources;
  4492 
  4493 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4494 order;
  4495 
  4496 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4497 timing flag supersedes proof_timing and Toplevel.trace;
  4498 
  4499 * ML: new combinators |>> and |>>> for incremental transformations
  4500 with secondary results (e.g. certain theory extensions):
  4501 
  4502 * ML: PureThy.add_defs gets additional argument to indicate potential
  4503 overloading (usually false);
  4504 
  4505 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4506 results;
  4507 
  4508 
  4509 
  4510 New in Isabelle99 (October 1999)
  4511 --------------------------------
  4512 
  4513 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4514 
  4515 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4516 are no longer simplified.  (This allows the simplifier to unfold recursive
  4517 functional programs.)  To restore the old behaviour, declare
  4518 
  4519     Delcongs [if_weak_cong];
  4520 
  4521 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4522 complement;
  4523 
  4524 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4525 
  4526 * HOL/datatype: mutual_induct_tac no longer exists --
  4527   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  4528 
  4529 * HOL/typedef: fixed type inference for representing set; type
  4530 arguments now have to occur explicitly on the rhs as type constraints;
  4531 
  4532 * ZF: The con_defs part of an inductive definition may no longer refer
  4533 to constants declared in the same theory;
  4534 
  4535 * HOL, ZF: the function mk_cases, generated by the inductive
  4536 definition package, has lost an argument.  To simplify its result, it
  4537 uses the default simpset instead of a supplied list of theorems.
  4538 
  4539 * HOL/List: the constructors of type list are now Nil and Cons;
  4540 
  4541 * Simplifier: the type of the infix ML functions
  4542         setSSolver addSSolver setSolver addSolver
  4543 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4544 for packaging solvers. A solver is created via
  4545         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4546 where the string argument is only a comment.
  4547 
  4548 
  4549 *** Proof tools ***
  4550 
  4551 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4552 decision procedure for linear arithmetic. Currently it is used for
  4553 types `nat', `int', and `real' in HOL (see below); it can, should and
  4554 will be instantiated for other types and logics as well.
  4555 
  4556 * The simplifier now accepts rewrite rules with flexible heads, eg
  4557      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4558   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4559   matching.
  4560 
  4561 
  4562 *** General ***
  4563 
  4564 * New Isabelle/Isar subsystem provides an alternative to traditional
  4565 tactical theorem proving; together with the ProofGeneral/isar user
  4566 interface it offers an interactive environment for developing human
  4567 readable proof documents (Isar == Intelligible semi-automated
  4568 reasoning); for further information see isatool doc isar-ref,
  4569 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  4570 
  4571 * improved and simplified presentation of theories: better HTML markup
  4572 (including colors), graph views in several sizes; isatool usedir now
  4573 provides a proper interface for user theories (via -P option); actual
  4574 document preparation based on (PDF)LaTeX is available as well (for
  4575 new-style theories only); see isatool doc system for more information;
  4576 
  4577 * native support for Proof General, both for classic Isabelle and
  4578 Isabelle/Isar;
  4579 
  4580 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  4581 using the graph browser tool;
  4582 
  4583 * Isabelle manuals now also available as PDF;
  4584 
  4585 * theory loader rewritten from scratch (may not be fully
  4586 bug-compatible); old loadpath variable has been replaced by show_path,
  4587 add_path, del_path, reset_path functions; new operations such as
  4588 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  4589 isatool doc ref);
  4590 
  4591 * improved isatool install: option -k creates KDE application icon,
  4592 option -p DIR installs standalone binaries;
  4593 
  4594 * added ML_PLATFORM setting (useful for cross-platform installations);
  4595 more robust handling of platform specific ML images for SML/NJ;
  4596 
  4597 * the settings environment is now statically scoped, i.e. it is never
  4598 created again in sub-processes invoked from isabelle, isatool, or
  4599 Isabelle;
  4600 
  4601 * path element specification '~~' refers to '$ISABELLE_HOME';
  4602 
  4603 * in locales, the "assumes" and "defines" parts may be omitted if
  4604 empty;
  4605 
  4606 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4607 long arrows);
  4608 
  4609 * new print_mode "HTML";
  4610 
  4611 * new flag show_tags controls display of tags of theorems (which are
  4612 basically just comments that may be attached by some tools);
  4613 
  4614 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4615 mode and goal output format:
  4616 
  4617 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4618 244c244
  4619 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4620 ---
  4621 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4622 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4623 181c181
  4624 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4625 ---
  4626 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4627 
  4628 * function bind_thms stores lists of theorems (cf. bind_thm);
  4629 
  4630 * new shorthand tactics ftac, eatac, datac, fatac;
  4631 
  4632 * qed (and friends) now accept "" as result name; in that case the
  4633 theorem is not stored, but proper checks and presentation of the
  4634 result still apply;
  4635 
  4636 * theorem database now also indexes constants "Trueprop", "all",
  4637 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4638 
  4639 
  4640 *** HOL ***
  4641 
  4642 ** HOL arithmetic **
  4643 
  4644 * There are now decision procedures for linear arithmetic over nat and
  4645 int:
  4646 
  4647 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4648 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4649 are treated as atomic; subformulae not involving type `nat' or `int'
  4650 are ignored; quantified subformulae are ignored unless they are
  4651 positive universal or negative existential. The tactic has to be
  4652 invoked by hand and can be a little bit slow. In particular, the
  4653 running time is exponential in the number of occurrences of `min' and
  4654 `max', and `-' on `nat'.
  4655 
  4656 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4657 (negated) (in)equalities among the premises and the conclusion into
  4658 account (i.e. no compound formulae) and does not know about `min' and
  4659 `max', and `-' on `nat'. It is fast and is used automatically by the
  4660 simplifier.
  4661 
  4662 NB: At the moment, these decision procedures do not cope with mixed
  4663 nat/int formulae where the two parts interact, such as `m < n ==>
  4664 int(m) < int(n)'.
  4665 
  4666 * HOL/Numeral provides a generic theory of numerals (encoded
  4667 efficiently as bit strings); setup for types nat/int/real is in place;
  4668 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4669 int, existing theories and proof scripts may require a few additional
  4670 type constraints;
  4671 
  4672 * integer division and remainder can now be performed on constant
  4673 arguments;
  4674 
  4675 * many properties of integer multiplication, division and remainder
  4676 are now available;
  4677 
  4678 * An interface to the Stanford Validity Checker (SVC) is available through the
  4679 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4680 are proved automatically.  SVC must be installed separately, and its results
  4681 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4682 invocation of the underlying oracle).  For SVC see
  4683   http://verify.stanford.edu/SVC
  4684 
  4685 * IsaMakefile: the HOL-Real target now builds an actual image;
  4686 
  4687 
  4688 ** HOL misc **
  4689 
  4690 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4691 (in Isabelle/Isar) -- by Gertrud Bauer;
  4692 
  4693 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4694 analysis for assembly languages with subtypes;
  4695 
  4696 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4697 -- avoids syntactic ambiguities and treats state, transition, and
  4698 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4699 changed syntax and (many) tactics;
  4700 
  4701 * HOL/inductive: Now also handles more general introduction rules such
  4702   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4703   theorems are now maintained within the theory (maintained via the
  4704   "mono" attribute);
  4705 
  4706 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4707   (using function types) such as
  4708 
  4709   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4710 
  4711 * HOL/record: record_simproc (part of the default simpset) takes care
  4712 of selectors applied to updated records; record_split_tac is no longer
  4713 part of the default claset; update_defs may now be removed from the
  4714 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4715 
  4716   claset_ref () := claset() addSWrapper record_split_wrapper;
  4717   Delsimprocs [record_simproc]
  4718 
  4719 * HOL/typedef: fixed type inference for representing set; type
  4720 arguments now have to occur explicitly on the rhs as type constraints;
  4721 
  4722 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4723 names rather than an ML expression;
  4724 
  4725 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4726 supplied later.  Program schemes can be defined, such as
  4727     "While B C s = (if B s then While B C (C s) else s)"
  4728 where the well-founded relation can be chosen after B and C have been given.
  4729 
  4730 * HOL/List: the constructors of type list are now Nil and Cons;
  4731 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4732 course, ML tools referring to List.list.op # etc. have to be adapted;
  4733 
  4734 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4735 disabled by default; run isabelle with option -m HOL to get back to
  4736 the original Gordon/HOL-style output;
  4737 
  4738 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4739 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4740 
  4741 * HOL basic syntax simplified (more orthogonal): all variants of
  4742 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4743 Eps operator is provided as well: "SOME x. P[x]";
  4744 
  4745 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4746 
  4747 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4748 thus available for user theories;
  4749 
  4750 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4751 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4752 time;
  4753 
  4754 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4755 several times and then mp;
  4756 
  4757 
  4758 *** LK ***
  4759 
  4760 * the notation <<...>> is now available as a notation for sequences of
  4761 formulas;
  4762 
  4763 * the simplifier is now installed
  4764 
  4765 * the axiom system has been generalized (thanks to Soren Heilmann)
  4766 
  4767 * the classical reasoner now has a default rule database
  4768 
  4769 
  4770 *** ZF ***
  4771 
  4772 * new primrec section allows primitive recursive functions to be given
  4773 directly (as in HOL) over datatypes and the natural numbers;
  4774 
  4775 * new tactics induct_tac and exhaust_tac for induction (or case
  4776 analysis) over datatypes and the natural numbers;
  4777 
  4778 * the datatype declaration of type T now defines the recursor T_rec;
  4779 
  4780 * simplification automatically does freeness reasoning for datatype
  4781 constructors;
  4782 
  4783 * automatic type-inference, with AddTCs command to insert new
  4784 type-checking rules;
  4785 
  4786 * datatype introduction rules are now added as Safe Introduction rules
  4787 to the claset;
  4788 
  4789 * the syntax "if P then x else y" is now available in addition to
  4790 if(P,x,y);
  4791 
  4792 
  4793 *** Internal programming interfaces ***
  4794 
  4795 * tuned simplifier trace output; new flag debug_simp;
  4796 
  4797 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4798 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4799 
  4800 * AxClass.axclass_tac lost the theory argument;
  4801 
  4802 * tuned current_goals_markers semantics: begin / end goal avoids
  4803 printing empty lines;
  4804 
  4805 * removed prs and prs_fn hook, which was broken because it did not
  4806 include \n in its semantics, forcing writeln to add one
  4807 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4808 string -> unit if you really want to output text without newline;
  4809 
  4810 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4811 plain output, interface builders may have to enable 'isabelle_font'
  4812 mode to get Isabelle font glyphs as before;
  4813 
  4814 * refined token_translation interface; INCOMPATIBILITY: output length
  4815 now of type real instead of int;
  4816 
  4817 * theory loader actions may be traced via new ThyInfo.add_hook
  4818 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4819 your own database of information attached to *whole* theories -- as
  4820 opposed to intra-theory data slots offered via TheoryDataFun;
  4821 
  4822 * proper handling of dangling sort hypotheses (at last!);
  4823 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4824 extra sort hypotheses that can be witnessed from the type signature;
  4825 the force_strip_shyps flag is gone, any remaining shyps are simply
  4826 left in the theorem (with a warning issued by strip_shyps_warning);
  4827 
  4828 
  4829 
  4830 New in Isabelle98-1 (October 1998)
  4831 ----------------------------------
  4832 
  4833 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4834 
  4835 * several changes of automated proof tools;
  4836 
  4837 * HOL: major changes to the inductive and datatype packages, including
  4838 some minor incompatibilities of theory syntax;
  4839 
  4840 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4841 called `inj_on';
  4842 
  4843 * HOL: removed duplicate thms in Arith:
  4844   less_imp_add_less  should be replaced by  trans_less_add1
  4845   le_imp_add_le      should be replaced by  trans_le_add1
  4846 
  4847 * HOL: unary minus is now overloaded (new type constraints may be
  4848 required);
  4849 
  4850 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4851 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4852 now taken as an integer constant.
  4853 
  4854 * Pure: ML function 'theory_of' renamed to 'theory';
  4855 
  4856 
  4857 *** Proof tools ***
  4858 
  4859 * Simplifier:
  4860   1. Asm_full_simp_tac is now more aggressive.
  4861      1. It will sometimes reorient premises if that increases their power to
  4862         simplify.
  4863      2. It does no longer proceed strictly from left to right but may also
  4864         rotate premises to achieve further simplification.
  4865      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4866      old Asm_full_simp_tac in that it does not rotate premises.
  4867   2. The simplifier now knows a little bit about nat-arithmetic.
  4868 
  4869 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4870 allows for selected deletion of wrappers, by introduction of names for
  4871 wrapper functionals.  This implies that addbefore, addSbefore,
  4872 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4873 and that adding two tactics with the same name overwrites the first
  4874 one (emitting a warning).
  4875   type wrapper = (int -> tactic) -> (int -> tactic)
  4876   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4877   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4878   delWrapper, delSWrapper: claset *  string            -> claset
  4879   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4880 
  4881 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4882 semantics; addbefore now affects only the unsafe part of step_tac
  4883 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4884 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4885 by Force_tac;
  4886 
  4887 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4888 compWrapper; added safe wrapper (and access functions for it);
  4889 
  4890 * HOL/split_all_tac is now much faster and fails if there is nothing
  4891 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4892 and the names of the automatically generated variables have changed.
  4893 split_all_tac has moved within claset() from unsafe wrappers to safe
  4894 wrappers, which means that !!-bound variables are split much more
  4895 aggressively, and safe_tac and clarify_tac now split such variables.
  4896 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4897 Note: the same holds for record_split_tac, which does the job of
  4898 split_all_tac for record fields.
  4899 
  4900 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4901 permanently to the default simpset using Addsplits just like
  4902 Addsimps. They can be removed via Delsplits just like
  4903 Delsimps. Lower-case versions are also available.
  4904 
  4905 * HOL/Simplifier: The rule split_if is now part of the default
  4906 simpset. This means that the simplifier will eliminate all occurrences
  4907 of if-then-else in the conclusion of a goal. To prevent this, you can
  4908 either remove split_if completely from the default simpset by
  4909 `Delsplits [split_if]' or remove it in a specific call of the
  4910 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4911 other case splitting rules to/from the default simpset: every datatype
  4912 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4913 t is the name of the datatype).
  4914 
  4915 * Classical reasoner / Simplifier combination: new force_tac (and
  4916 derivatives Force_tac, force) combines rewriting and classical
  4917 reasoning (and whatever other tools) similarly to auto_tac, but is
  4918 aimed to solve the given subgoal completely.
  4919 
  4920 
  4921 *** General ***
  4922 
  4923 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4924 and `goalw': the theory is no longer needed as an explicit argument -
  4925 the current theory context is used; assumptions are no longer returned
  4926 at the ML-level unless one of them starts with ==> or !!; it is
  4927 recommended to convert to these new commands using isatool fixgoal
  4928 (backup your sources first!);
  4929 
  4930 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4931 the current theory context, and 'theory' to lookup stored theories;
  4932 
  4933 * new theory section 'locale' for declaring constants, assumptions and
  4934 definitions that have local scope;
  4935 
  4936 * new theory section 'nonterminals' for purely syntactic types;
  4937 
  4938 * new theory section 'setup' for generic ML setup functions
  4939 (e.g. package initialization);
  4940 
  4941 * the distribution now includes Isabelle icons: see
  4942 lib/logo/isabelle-{small,tiny}.xpm;
  4943 
  4944 * isatool install - install binaries with absolute references to
  4945 ISABELLE_HOME/bin;
  4946 
  4947 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4948 
  4949 * print mode 'emacs' reserved for Isamode;
  4950 
  4951 * support multiple print (ast) translations per constant name;
  4952 
  4953 * theorems involving oracles are now printed with a suffixed [!];
  4954 
  4955 
  4956 *** HOL ***
  4957 
  4958 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4959 
  4960 * HOL/inductive package reorganized and improved: now supports mutual
  4961 definitions such as
  4962 
  4963   inductive EVEN ODD
  4964     intrs
  4965       null "0 : EVEN"
  4966       oddI "n : EVEN ==> Suc n : ODD"
  4967       evenI "n : ODD ==> Suc n : EVEN"
  4968 
  4969 new theorem list "elims" contains an elimination rule for each of the
  4970 recursive sets; inductive definitions now handle disjunctive premises
  4971 correctly (also ZF);
  4972 
  4973 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4974 "mutual_induct" no longer exists - the induction rule is always
  4975 contained in "induct";
  4976 
  4977 
  4978 * HOL/datatype package re-implemented and greatly improved: now
  4979 supports mutually recursive datatypes such as
  4980 
  4981   datatype
  4982     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4983             | SUM ('a aexp) ('a aexp)
  4984             | DIFF ('a aexp) ('a aexp)
  4985             | NUM 'a
  4986   and
  4987     'a bexp = LESS ('a aexp) ('a aexp)
  4988             | AND ('a bexp) ('a bexp)
  4989             | OR ('a bexp) ('a bexp)
  4990 
  4991 as well as indirectly recursive datatypes such as
  4992 
  4993   datatype
  4994     ('a, 'b) term = Var 'a
  4995                   | App 'b ((('a, 'b) term) list)
  4996 
  4997 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4998 induction on mutually / indirectly recursive datatypes.
  4999 
  5000 Primrec equations are now stored in theory and can be accessed via
  5001 <function_name>.simps.
  5002 
  5003 INCOMPATIBILITIES:
  5004 
  5005   - Theories using datatypes must now have theory Datatype as an
  5006     ancestor.
  5007   - The specific <typename>.induct_tac no longer exists - use the
  5008     generic induct_tac instead.
  5009   - natE has been renamed to nat.exhaust - use exhaust_tac
  5010     instead of res_inst_tac ... natE. Note that the variable
  5011     names in nat.exhaust differ from the names in natE, this
  5012     may cause some "fragile" proofs to fail.
  5013   - The theorems split_<typename>_case and split_<typename>_case_asm
  5014     have been renamed to <typename>.split and <typename>.split_asm.
  5015   - Since default sorts of type variables are now handled correctly,
  5016     some datatype definitions may have to be annotated with explicit
  5017     sort constraints.
  5018   - Primrec definitions no longer require function name and type
  5019     of recursive argument.
  5020 
  5021 Consider using isatool fixdatatype to adapt your theories and proof
  5022 scripts to the new package (backup your sources first!).
  5023 
  5024 
  5025 * HOL/record package: considerably improved implementation; now
  5026 includes concrete syntax for record types, terms, updates; theorems
  5027 for surjective pairing and splitting !!-bound record variables; proof
  5028 support is as follows:
  5029 
  5030   1) standard conversions (selectors or updates applied to record
  5031 constructor terms) are part of the standard simpset;
  5032 
  5033   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5034 made part of standard simpset and claset via addIffs;
  5035 
  5036   3) a tactic for record field splitting (record_split_tac) is part of
  5037 the standard claset (addSWrapper);
  5038 
  5039 To get a better idea about these rules you may retrieve them via
  5040 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5041 the name of your record type.
  5042 
  5043 The split tactic 3) conceptually simplifies by the following rule:
  5044 
  5045   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5046 
  5047 Thus any record variable that is bound by meta-all will automatically
  5048 blow up into some record constructor term, consequently the
  5049 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5050 solve record problems automatically.
  5051 
  5052 
  5053 * reorganized the main HOL image: HOL/Integ and String loaded by
  5054 default; theory Main includes everything;
  5055 
  5056 * automatic simplification of integer sums and comparisons, using cancellation;
  5057 
  5058 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5059 
  5060 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5061 
  5062 * many new identities for unions, intersections, set difference, etc.;
  5063 
  5064 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5065 called split_if, split_split, split_sum_case and split_nat_case (to go
  5066 with add/delsplits);
  5067 
  5068 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5069 (?x::unit) = (); this is made part of the default simpset, which COULD
  5070 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5071 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5072 unit_abs_eta_conv is added in order to counter the effect of
  5073 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5074 %u.f();
  5075 
  5076 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5077 makes more sense);
  5078 
  5079 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5080   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5081   disjointness reasoning but breaking a few old proofs.
  5082 
  5083 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5084 to 'converse' from 'inverse' (for compatibility with ZF and some
  5085 literature);
  5086 
  5087 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5088 the well-founded relation;
  5089 
  5090 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5091     Compl A.  The "Compl" syntax remains available as input syntax for this
  5092     release ONLY.
  5093 
  5094 * HOL/Update: new theory of function updates:
  5095     f(a:=b) == %x. if x=a then b else f x
  5096 may also be iterated as in f(a:=b,c:=d,...);
  5097 
  5098 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5099 
  5100 * HOL/List:
  5101   - new function list_update written xs[i:=v] that updates the i-th
  5102     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5103   - new function `upt' written [i..j(] which generates the list
  5104     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5105     bound write [i..j], which is a shorthand for [i..j+1(].
  5106   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5107 
  5108 * HOL/Arith:
  5109   - removed 'pred' (predecessor) function;
  5110   - generalized some theorems about n-1;
  5111   - many new laws about "div" and "mod";
  5112   - new laws about greatest common divisors (see theory ex/Primes);
  5113 
  5114 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5115 instead of "inverse";
  5116 
  5117 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5118   of the multiset ordering;
  5119 
  5120 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5121   (not included by default);
  5122 
  5123 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5124 
  5125 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5126   programs, i.e. different program variables may have different types.
  5127 
  5128 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5129   [previously, this check worked only if the rewrite rule was unconditional]
  5130   Now rew can involve either definitions or equalities (either == or =).
  5131 
  5132 
  5133 *** ZF ***
  5134 
  5135 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5136   only the theorems proved on ZF.ML;
  5137 
  5138 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5139   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5140   disjointness reasoning but breaking a few old proofs.
  5141 
  5142 * ZF/Update: new theory of function updates
  5143     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5144   may also be iterated as in f(a:=b,c:=d,...);
  5145 
  5146 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5147 
  5148 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5149   [previously, this check worked only if the rewrite rule was unconditional]
  5150   Now rew can involve either definitions or equalities (either == or =).
  5151 
  5152 * case_tac provided for compatibility with HOL
  5153     (like the old excluded_middle_tac, but with subgoals swapped)
  5154 
  5155 
  5156 *** Internal programming interfaces ***
  5157 
  5158 * Pure: several new basic modules made available for general use, see
  5159 also src/Pure/README;
  5160 
  5161 * improved the theory data mechanism to support encapsulation (data
  5162 kind name replaced by private Object.kind, acting as authorization
  5163 key); new type-safe user interface via functor TheoryDataFun; generic
  5164 print_data function becomes basically useless;
  5165 
  5166 * removed global_names compatibility flag -- all theory declarations
  5167 are qualified by default;
  5168 
  5169 * module Pure/Syntax now offers quote / antiquote translation
  5170 functions (useful for Hoare logic etc. with implicit dependencies);
  5171 see HOL/ex/Antiquote for an example use;
  5172 
  5173 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5174 cterm -> thm;
  5175 
  5176 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5177 subgoal;
  5178 
  5179 * Display.print_goals function moved to Locale.print_goals;
  5180 
  5181 * standard print function for goals supports current_goals_markers
  5182 variable for marking begin of proof, end of proof, start of goal; the
  5183 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5184 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5185 for example;
  5186 
  5187 
  5188 
  5189 New in Isabelle98 (January 1998)
  5190 --------------------------------
  5191 
  5192 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5193 
  5194 * changed lexical syntax of terms / types: dots made part of long
  5195 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5196 
  5197 * simpset (and claset) reference variable replaced by functions
  5198 simpset / simpset_ref;
  5199 
  5200 * no longer supports theory aliases (via merge) and non-trivial
  5201 implicit merge of thms' signatures;
  5202 
  5203 * most internal names of constants changed due to qualified names;
  5204 
  5205 * changed Pure/Sequence interface (see Pure/seq.ML);
  5206 
  5207 
  5208 *** General Changes ***
  5209 
  5210 * hierachically structured name spaces (for consts, types, axms, thms
  5211 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5212 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5213 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5214 long_names for fully qualified output names; NOTE: ML programs
  5215 (special tactics, packages etc.) referring to internal names may have
  5216 to be adapted to cope with fully qualified names; in case of severe
  5217 backward campatibility problems try setting 'global_names' at compile
  5218 time to have enrything declared within a flat name space; one may also
  5219 fine tune name declarations in theories via the 'global' and 'local'
  5220 section;
  5221 
  5222 * reimplemented the implicit simpset and claset using the new anytype
  5223 data filed in signatures; references simpset:simpset ref etc. are
  5224 replaced by functions simpset:unit->simpset and
  5225 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5226 to patch your ML files accordingly;
  5227 
  5228 * HTML output now includes theory graph data for display with Java
  5229 applet or isatool browser; data generated automatically via isatool
  5230 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5231 
  5232 * defs may now be conditional; improved rewrite_goals_tac to handle
  5233 conditional equations;
  5234 
  5235 * defs now admits additional type arguments, using TYPE('a) syntax;
  5236 
  5237 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5238 creates a new theory node; implicit merge of thms' signatures is
  5239 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5240 transfer:theory->thm->thm in (rare) cases;
  5241 
  5242 * improved handling of draft signatures / theories; draft thms (and
  5243 ctyps, cterms) are automatically promoted to real ones;
  5244 
  5245 * slightly changed interfaces for oracles: admit many per theory, named
  5246 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5247 
  5248 * print_goals: optional output of const types (set show_consts and
  5249 show_types);
  5250 
  5251 * improved output of warnings (###) and errors (***);
  5252 
  5253 * subgoal_tac displays a warning if the new subgoal has type variables;
  5254 
  5255 * removed old README and Makefiles;
  5256 
  5257 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5258 
  5259 * removed obsolete init_pps and init_database;
  5260 
  5261 * deleted the obsolete tactical STATE, which was declared by
  5262     fun STATE tacfun st = tacfun st st;
  5263 
  5264 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5265 (which abbreviates $HOME);
  5266 
  5267 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5268 use isatool fixseq to adapt your ML programs (this works for fully
  5269 qualified references to the Sequence structure only!);
  5270 
  5271 * use_thy no longer requires writable current directory; it always
  5272 reloads .ML *and* .thy file, if either one is out of date;
  5273 
  5274 
  5275 *** Classical Reasoner ***
  5276 
  5277 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5278 tactics that use classical reasoning to simplify a subgoal without
  5279 splitting it into several subgoals;
  5280 
  5281 * Safe_tac: like safe_tac but uses the default claset;
  5282 
  5283 
  5284 *** Simplifier ***
  5285 
  5286 * added simplification meta rules:
  5287     (asm_)(full_)simplify: simpset -> thm -> thm;
  5288 
  5289 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5290 logics (again);
  5291 
  5292 * added prems argument to simplification procedures;
  5293 
  5294 * HOL, FOL, ZF: added infix function `addsplits':
  5295   instead of `<simpset> setloop (split_tac <thms>)'
  5296   you can simply write `<simpset> addsplits <thms>'
  5297 
  5298 
  5299 *** Syntax ***
  5300 
  5301 * TYPE('a) syntax for type reflection terms;
  5302 
  5303 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5304 
  5305 * pretty printer: changed order of mixfix annotation preference (again!);
  5306 
  5307 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5308 
  5309 
  5310 *** HOL ***
  5311 
  5312 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5313   with `addloop' of the simplifier to faciliate case splitting in premises.
  5314 
  5315 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5316 
  5317 * HOL/Auth: new protocol proofs including some for the Internet
  5318   protocol TLS;
  5319 
  5320 * HOL/Map: new theory of `maps' a la VDM;
  5321 
  5322 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5323 cancelling out common nat summands from =, <, <= (in)equalities, or
  5324 differences; simplification procedures nat_cancel_factor for
  5325 cancelling common factor from =, <, <= (in)equalities over natural
  5326 sums; nat_cancel contains both kinds of procedures, it is installed by
  5327 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5328 
  5329 * HOL/simplifier: terms of the form
  5330   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5331   are rewritten to
  5332   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5333   and those of the form
  5334   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5335   are rewritten to
  5336   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5337 
  5338 * HOL/datatype
  5339   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5340 
  5341   P(t_case f1 ... fn x) =
  5342      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5343         ...
  5344        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5345      )
  5346 
  5347   and a theorem `split_t_case_asm' of the form
  5348 
  5349   P(t_case f1 ... fn x) =
  5350     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5351         ...
  5352        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5353      )
  5354   which can be added to a simpset via `addsplits'. The existing theorems
  5355   expand_list_case and expand_option_case have been renamed to
  5356   split_list_case and split_option_case.
  5357 
  5358 * HOL/Arithmetic:
  5359   - `pred n' is automatically converted to `n-1'.
  5360     Users are strongly encouraged not to use `pred' any longer,
  5361     because it will disappear altogether at some point.
  5362   - Users are strongly encouraged to write "0 < n" rather than
  5363     "n ~= 0". Theorems and proof tools have been modified towards this
  5364     `standard'.
  5365 
  5366 * HOL/Lists:
  5367   the function "set_of_list" has been renamed "set" (and its theorems too);
  5368   the function "nth" now takes its arguments in the reverse order and
  5369   has acquired the infix notation "!" as in "xs!n".
  5370 
  5371 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5372 
  5373 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5374   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5375 
  5376 * HOL/record: extensible records with schematic structural subtyping
  5377 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5378 still lacks various theorems and concrete record syntax;
  5379 
  5380 
  5381 *** HOLCF ***
  5382 
  5383 * removed "axioms" and "generated by" sections;
  5384 
  5385 * replaced "ops" section by extended "consts" section, which is capable of
  5386   handling the continuous function space "->" directly;
  5387 
  5388 * domain package:
  5389   . proves theorems immediately and stores them in the theory,
  5390   . creates hierachical name space,
  5391   . now uses normal mixfix annotations (instead of cinfix...),
  5392   . minor changes to some names and values (for consistency),
  5393   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5394   . separator between mutual domain defs: changed "," to "and",
  5395   . improved handling of sort constraints;  now they have to
  5396     appear on the left-hand side of the equations only;
  5397 
  5398 * fixed LAM <x,y,zs>.b syntax;
  5399 
  5400 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5401 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5402 
  5403 
  5404 *** FOL and ZF ***
  5405 
  5406 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5407   with `addloop' of the simplifier to faciliate case splitting in premises.
  5408 
  5409 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5410 in HOL, they strip ALL and --> from proved theorems;
  5411 
  5412 
  5413 
  5414 New in Isabelle94-8 (May 1997)
  5415 ------------------------------
  5416 
  5417 *** General Changes ***
  5418 
  5419 * new utilities to build / run / maintain Isabelle etc. (in parts
  5420 still somewhat experimental); old Makefiles etc. still functional;
  5421 
  5422 * new 'Isabelle System Manual';
  5423 
  5424 * INSTALL text, together with ./configure and ./build scripts;
  5425 
  5426 * reimplemented type inference for greater efficiency, better error
  5427 messages and clean internal interface;
  5428 
  5429 * prlim command for dealing with lots of subgoals (an easier way of
  5430 setting goals_limit);
  5431 
  5432 
  5433 *** Syntax ***
  5434 
  5435 * supports alternative (named) syntax tables (parser and pretty
  5436 printer); internal interface is provided by add_modesyntax(_i);
  5437 
  5438 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5439 be used in conjunction with the Isabelle symbol font; uses the
  5440 "symbols" syntax table;
  5441 
  5442 * added token_translation interface (may translate name tokens in
  5443 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5444 the current print_mode); IMPORTANT: user print translation functions
  5445 are responsible for marking newly introduced bounds
  5446 (Syntax.mark_boundT);
  5447 
  5448 * token translations for modes "xterm" and "xterm_color" that display
  5449 names in bold, underline etc. or colors (which requires a color
  5450 version of xterm);
  5451 
  5452 * infixes may now be declared with names independent of their syntax;
  5453 
  5454 * added typed_print_translation (like print_translation, but may
  5455 access type of constant);
  5456 
  5457 
  5458 *** Classical Reasoner ***
  5459 
  5460 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5461 some limitations.  Blast_tac...
  5462   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5463   + ignores elimination rules that don't have the correct format
  5464         (the conclusion MUST be a formula variable)
  5465   + ignores types, which can make HOL proofs fail
  5466   + rules must not require higher-order unification, e.g. apply_type in ZF
  5467     [message "Function Var's argument not a bound variable" relates to this]
  5468   + its proof strategy is more general but can actually be slower
  5469 
  5470 * substitution with equality assumptions no longer permutes other
  5471 assumptions;
  5472 
  5473 * minor changes in semantics of addafter (now called addaltern); renamed
  5474 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5475 (and access functions for it);
  5476 
  5477 * improved combination of classical reasoner and simplifier:
  5478   + functions for handling clasimpsets
  5479   + improvement of addss: now the simplifier is called _after_ the
  5480     safe steps.
  5481   + safe variant of addss called addSss: uses safe simplifications
  5482     _during_ the safe steps. It is more complete as it allows multiple
  5483     instantiations of unknowns (e.g. with slow_tac).
  5484 
  5485 *** Simplifier ***
  5486 
  5487 * added interface for simplification procedures (functions that
  5488 produce *proven* rewrite rules on the fly, depending on current
  5489 redex);
  5490 
  5491 * ordering on terms as parameter (used for ordered rewriting);
  5492 
  5493 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5494 
  5495 * the solver is now split into a safe and an unsafe part.
  5496 This should be invisible for the normal user, except that the
  5497 functions setsolver and addsolver have been renamed to setSolver and
  5498 addSolver; added safe_asm_full_simp_tac;
  5499 
  5500 
  5501 *** HOL ***
  5502 
  5503 * a generic induction tactic `induct_tac' which works for all datatypes and
  5504 also for type `nat';
  5505 
  5506 * a generic case distinction tactic `exhaust_tac' which works for all
  5507 datatypes and also for type `nat';
  5508 
  5509 * each datatype comes with a function `size';
  5510 
  5511 * patterns in case expressions allow tuple patterns as arguments to
  5512 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5513 
  5514 * primrec now also works with type nat;
  5515 
  5516 * recdef: a new declaration form, allows general recursive functions to be
  5517 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5518 
  5519 * the constant for negation has been renamed from "not" to "Not" to
  5520 harmonize with FOL, ZF, LK, etc.;
  5521 
  5522 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5523 infinite lists;
  5524 
  5525 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5526 
  5527 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  5528 problems in commutative rings, using axiomatic type classes for + and *;
  5529 
  5530 * more examples in HOL/MiniML and HOL/Auth;
  5531 
  5532 * more default rewrite rules for quantifiers, union/intersection;
  5533 
  5534 * a new constant `arbitrary == @x.False';
  5535 
  5536 * HOLCF/IOA replaces old HOL/IOA;
  5537 
  5538 * HOLCF changes: derived all rules and arities
  5539   + axiomatic type classes instead of classes
  5540   + typedef instead of faking type definitions
  5541   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5542   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5543   + eliminated the types void, one, tr
  5544   + use unit lift and bool lift (with translations) instead of one and tr
  5545   + eliminated blift from Lift3.thy (use Def instead of blift)
  5546   all eliminated rules are derived as theorems --> no visible changes ;
  5547 
  5548 
  5549 *** ZF ***
  5550 
  5551 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5552 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5553 as ZF_cs addSIs [equalityI];
  5554 
  5555 
  5556 
  5557 New in Isabelle94-7 (November 96)
  5558 ---------------------------------
  5559 
  5560 * allowing negative levels (as offsets) in prlev and choplev;
  5561 
  5562 * super-linear speedup for large simplifications;
  5563 
  5564 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  5565 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  5566 FAIL); can suppress it using the command Delsimps (ex_simps @
  5567 all_simps); De Morgan laws are also now included, by default;
  5568 
  5569 * improved printing of ==>  :  ~:
  5570 
  5571 * new object-logic "Sequents" adds linear logic, while replacing LK
  5572 and Modal (thanks to Sara Kalvala);
  5573 
  5574 * HOL/Auth: correctness proofs for authentication protocols;
  5575 
  5576 * HOL: new auto_tac combines rewriting and classical reasoning (many
  5577 examples on HOL/Auth);
  5578 
  5579 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  5580 the rewriter and classical reasoner simultaneously;
  5581 
  5582 * function uresult no longer returns theorems in "standard" format;
  5583 regain previous version by: val uresult = standard o uresult;
  5584 
  5585 
  5586 
  5587 New in Isabelle94-6
  5588 -------------------
  5589 
  5590 * oracles -- these establish an interface between Isabelle and trusted
  5591 external reasoners, which may deliver results as theorems;
  5592 
  5593 * proof objects (in particular record all uses of oracles);
  5594 
  5595 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  5596 
  5597 * "constdefs" section in theory files;
  5598 
  5599 * "primrec" section (HOL) no longer requires names;
  5600 
  5601 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  5602 
  5603 
  5604 
  5605 New in Isabelle94-5
  5606 -------------------
  5607 
  5608 * reduced space requirements;
  5609 
  5610 * automatic HTML generation from theories;
  5611 
  5612 * theory files no longer require "..." (quotes) around most types;
  5613 
  5614 * new examples, including two proofs of the Church-Rosser theorem;
  5615 
  5616 * non-curried (1994) version of HOL is no longer distributed;
  5617 
  5618 
  5619 
  5620 New in Isabelle94-4
  5621 -------------------
  5622 
  5623 * greatly reduced space requirements;
  5624 
  5625 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5626 
  5627 * searchable theorem database (see the section "Retrieving theorems" on
  5628 page 8 of the Reference Manual);
  5629 
  5630 * new examples, including Grabczewski's monumental case study of the
  5631 Axiom of Choice;
  5632 
  5633 * The previous version of HOL renamed to Old_HOL;
  5634 
  5635 * The new version of HOL (previously called CHOL) uses a curried syntax
  5636 for functions.  Application looks like f a b instead of f(a,b);
  5637 
  5638 * Mutually recursive inductive definitions finally work in HOL;
  5639 
  5640 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5641 translates to the operator "split";
  5642 
  5643 
  5644 
  5645 New in Isabelle94-3
  5646 -------------------
  5647 
  5648 * new infix operator, addss, allowing the classical reasoner to
  5649 perform simplification at each step of its search.  Example:
  5650         fast_tac (cs addss ss)
  5651 
  5652 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5653 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5654 look like (a,b) instead of <a,b>;
  5655 
  5656 * PLEASE NOTE: CHOL will eventually replace HOL!
  5657 
  5658 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5659 It translates to the operator "split".  A new theory of integers is available;
  5660 
  5661 * In ZF, integer numerals now denote two's-complement binary integers.
  5662 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5663 
  5664 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5665 of the Axiom of Choice;
  5666 
  5667 
  5668 
  5669 New in Isabelle94-2
  5670 -------------------
  5671 
  5672 * Significantly faster resolution;
  5673 
  5674 * the different sections in a .thy file can now be mixed and repeated
  5675 freely;
  5676 
  5677 * Database of theorems for FOL, HOL and ZF.  New
  5678 commands including qed, qed_goal and bind_thm store theorems in the database.
  5679 
  5680 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5681 a given theory (thms_of), or find out what theory a theorem was proved in
  5682 (theory_of_thm);
  5683 
  5684 * Bugs fixed in the inductive definition and datatype packages;
  5685 
  5686 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5687 and HOL_dup_cs obsolete;
  5688 
  5689 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5690 have been removed;
  5691 
  5692 * Simpler definition of function space in ZF;
  5693 
  5694 * new results about cardinal and ordinal arithmetic in ZF;
  5695 
  5696 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5697 types;
  5698 
  5699 :mode=text:wrap=hard:maxLineLen=72:
  5700 
  5701 
  5702 $Id$