NEWS
author haftmann
Tue Sep 16 09:21:22 2008 +0200 (2008-09-16)
changeset 28227 77221ee0f7b9
parent 28178 e56b8b044bef
child 28233 f14f34194f63
permissions -rw-r--r--
generic value command
     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 * Changed defaults for unify configuration options:
    23 
    24   unify_trace_bound = 50 (formerly 25)
    25   unify_search_bound = 60 (formerly 30)
    26 
    27 * Different bookkeeping for code equations:
    28   a) On theory merge, the last set of code equations for a particular constant
    29      is taken (in accordance with the policy applied by other parts of the
    30      code generator framework).
    31   b) Code equations stemming from explicit declarations (e.g. code attribute)
    32      gain priority over default code equations stemming from definition, primrec,
    33      fun etc.
    34   INCOMPATIBILITY.
    35 
    36 * Global versions of theorems stemming from classes do not carry
    37 a parameter prefix any longer.  INCOMPATIBILITY.
    38 
    39 * Dropped "locale (open)".  INCOMPATBILITY.
    40 
    41 * Interpretation commands no longer attempt to simplify goal.
    42 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
    43 methods intro_locales and unfold_locales to clarify.
    44 
    45 * Interpretation commands no longer accept interpretation attributes.
    46 INCOMPATBILITY.
    47 
    48 * Command 'instance': attached definitions no longer accepted.
    49 INCOMPATIBILITY, use proper 'instantiation' target.
    50 
    51 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
    52 
    53 * The 'axiomatization' command now only works within a global theory
    54 context.  INCOMPATIBILITY.
    55 
    56 
    57 *** Document preparation ***
    58 
    59 * Antiquotation @{lemma} now imitates a regular terminal proof,
    60 demanding keyword 'by' and supporting the full method expression
    61 syntax just like the Isar command 'by'.
    62 
    63 
    64 *** HOL ***
    65 
    66 * HOL/Main: command "value" now integrates different evaluation mechanisms.
    67 The result of the first successful evaluation mechanism is printed.
    68 In square brackets a particular named evaluation mechanisms may be specified
    69 (currently, [SML], [code] or [nbe]).  See further HOL/ex/Eval_Examples.thy.
    70 
    71 * HOL/Orderings: class "wellorder" moved here, with explicit induction
    72 rule "less_induct" as assumption.  For instantiation of "wellorder" by
    73 means of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.
    74 
    75 * HOL/Orderings: added class "preorder" as superclass of "order".
    76 INCOMPATIBILITY: Instantiation proofs for order, linorder
    77 etc. slightly changed.  Some theorems named order_class.* now named
    78 preorder_class.*.
    79 
    80 * HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
    81 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
    82 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
    83 of lemmas from Divides has been generalized from nat to class
    84 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
    85 renames resulting from duplicate elimination:
    86 
    87     dvd_def_mod ~>          dvd_eq_mod_eq_0
    88     zero_dvd_iff ~>         dvd_0_left_iff
    89     DIVISION_BY_ZERO_DIV ~> div_by_0
    90     DIVISION_BY_ZERO_MOD ~> mod_by_0
    91     mult_div ~>             div_mult_self2_is_id
    92     mult_mod ~>             mod_mult_self2_is_0
    93 
    94 * HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
    95 zlcm (for int); carried together from various gcd/lcm developements in
    96 the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
    97 corresponding theorems renamed accordingly.  INCOMPATIBILY.  To
    98 recover tupled syntax, use syntax declarations like:
    99 
   100     hide (open) const gcd
   101     abbreviation gcd where
   102       "gcd == (%(a, b). GCD.gcd a b)"
   103     notation (output)
   104       GCD.gcd ("gcd '(_, _')")
   105 
   106 (analogously for lcm, zgcd, zlcm).
   107 
   108 * HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   109 
   110 * New ML antiquotation @{code}: takes constant as argument, generates
   111 corresponding code in background and inserts name of the corresponding
   112 resulting ML value/function/datatype constructor binding in place.
   113 All occurrences of @{code} with a single ML block are generated
   114 simultaneously.  Provides a generic and safe interface for
   115 instrumentalizing code generation.  See HOL/ex/Code_Antiq for a toy
   116 example, or HOL/Complex/ex/ReflectedFerrack for a more ambitious
   117 application.  In future you ought refrain from ad-hoc compiling
   118 generated SML code on the ML toplevel.  Note that (for technical
   119 reasons) @{code} cannot refer to constants for which user-defined
   120 serializations are set.  Refer to the corresponding ML counterpart
   121 directly in that cases.
   122 
   123 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   124 Complex_Main.thy remain as they are.
   125 
   126 * New image HOL-Plain provides a minimal HOL with the most important
   127 tools available (inductive, datatype, primrec, ...).  By convention
   128 the corresponding theory Plain should be ancestor of every further
   129 (library) theory.  Some library theories now have ancestor Plain
   130 (instead of Main), thus theory Main occasionally has to be imported
   131 explicitly.
   132 
   133 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   134 as the structured Isar versions "cases" and "induct", cf. the
   135 corresponding "cases" and "induct" attributes.  Mutual induction rules
   136 are now presented as a list of individual projections
   137 (e.g. foo_bar.inducts for types foo and bar); the old format with
   138 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   139 rare situations a different rule is selected --- notably nested tuple
   140 elimination instead of former prod.exhaust: use explicit (case_tac t
   141 rule: prod.exhaust) here.
   142 
   143 * Attributes "cases", "induct", "coinduct" support "del" option.
   144 
   145 * Removed fact "case_split_thm", which duplicates "case_split".
   146 
   147 * Command 'rep_datatype': instead of theorem names the command now
   148 takes a list of terms denoting the constructors of the type to be
   149 represented as datatype.  The characteristic theorems have to be
   150 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   151 have disappeared in favour of existing ones:
   152 
   153     unit_induct                 ~> unit.induct
   154     prod_induct                 ~> prod.induct
   155     sum_induct                  ~> sum.induct
   156     Suc_Suc_eq                  ~> nat.inject
   157     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   158 
   159 * Library/Nat_Infinity: added addition, numeral syntax and more
   160 instantiations for algebraic structures.  Removed some duplicate
   161 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   162 
   163 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   164 menu.
   165 
   166 
   167 *** HOL-Algebra ***
   168 
   169 * New locales for orders and lattices where the equivalence relation
   170   is not restricted to equality.  INCOMPATIBILITY: all order and
   171   lattice locales use a record structure with field eq for the
   172   equivalence.
   173 
   174 * New theory of factorial domains.
   175 
   176 * Units_l_inv and Units_r_inv are now simprules by default.
   177 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   178 and/or r_inv will now also require deletion of these lemmas.
   179 
   180 * Renamed the following theorems.  INCOMPATIBILITY.
   181 UpperD ~> Upper_memD
   182 LowerD ~> Lower_memD
   183 least_carrier ~> least_closed
   184 greatest_carrier ~> greatest_closed
   185 greatest_Lower_above ~> greatest_Lower_below
   186 one_zero ~> carrier_one_zero
   187 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   188 
   189 
   190 *** HOL-NSA ***
   191 
   192 * Created new image HOL-NSA, containing theories of nonstandard
   193 analysis which were previously part of HOL-Complex.  Entry point
   194 Hyperreal.thy remains valid, but theories formerly using
   195 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   196 
   197 
   198 *** ZF ***
   199 
   200 * Proof of Zorn's Lemma for partial orders.
   201 
   202 
   203 *** ML ***
   204 
   205 * Generic Toplevel.add_hook interface allows to analyze the result of
   206 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   207 for theorem dependency output of transactions resulting in a new
   208 theory state.
   209 
   210 * Name bindings in higher specification mechanisms (notably
   211 LocalTheory.define, LocalTheory.note, and derived packages) are now
   212 formalized as type Name.binding, replacing old bstring.
   213 INCOMPATIBILITY, need to wrap strings via Name.binding function, see
   214 also Name.name_of.  Packages should pass name bindings given by the
   215 user to underlying specification mechanisms; this enables precise
   216 tracking of source positions, for example.
   217 
   218 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   219 LocalTheory.note etc.) now refer to the *full* internal name, not the
   220 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   221 
   222 * Rules and tactics that read instantiations (read_instantiate,
   223 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   224 context, which is required for parsing and type-checking.  Moreover,
   225 the variables are specified as plain indexnames, not string encodings
   226 thereof.  INCOMPATIBILITY.
   227 
   228 * Disposed old type and term read functions (Sign.read_def_typ,
   229 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   230 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   231 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   232 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   233 resort for legacy applications.
   234 
   235 * Antiquotations: block-structured compilation context indicated by
   236 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   237 
   238   @{let ?pat = term}                      - term abbreviation (HO matching)
   239   @{note name = fact}                     - fact abbreviation
   240   @{thm fact}                             - singleton fact (with attributes)
   241   @{thms fact}                            - general fact (with attributes)
   242   @{lemma prop by method}                 - singleton goal
   243   @{lemma prop by meth1 meth2}            - singleton goal
   244   @{lemma prop1 ... propN by method}      - general goal
   245   @{lemma prop1 ... propN by meth1 meth2} - general goal
   246   @{lemma (open) ...}                     - open derivation
   247 
   248 
   249 *** System ***
   250 
   251 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   252 the Isabelle process into a JVM/Scala application.  See
   253 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   254 process wrapper has been discontinued.)
   255 
   256 * Status messages (with exact source position information) are
   257 emitted, if proper markup print mode is enabled.  This allows
   258 user-interface components to provide detailed feedback on internal
   259 prover operations.
   260 
   261 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   262 
   263 
   264 
   265 New in Isabelle2008 (June 2008)
   266 -------------------------------
   267 
   268 *** General ***
   269 
   270 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   271 and updated, with formally checked references as hyperlinks.
   272 
   273 * Theory loader: use_thy (and similar operations) no longer set the
   274 implicit ML context, which was occasionally hard to predict and in
   275 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   276 provides a proper context already.
   277 
   278 * Theory loader: old-style ML proof scripts being *attached* to a thy
   279 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   280 'use' within a theory file will do the job.
   281 
   282 * Name space merge now observes canonical order, i.e. the second space
   283 is inserted into the first one, while existing entries in the first
   284 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   285 swap theory imports.
   286 
   287 * Syntax: symbol \<chi> is now considered a letter.  Potential
   288 INCOMPATIBILITY in identifier syntax etc.
   289 
   290 * Outer syntax: string tokens no longer admit escaped white space,
   291 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   292 white space without escapes.
   293 
   294 * Outer syntax: string tokens may contain arbitrary character codes
   295 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   296 "foo_bar".
   297 
   298 
   299 *** Pure ***
   300 
   301 * Context-dependent token translations.  Default setup reverts locally
   302 fixed variables, and adds hilite markup for undeclared frees.
   303 
   304 * Unused theorems can be found using the new command 'unused_thms'.
   305 There are three ways of invoking it:
   306 
   307 (1) unused_thms
   308      Only finds unused theorems in the current theory.
   309 
   310 (2) unused_thms thy_1 ... thy_n -
   311      Finds unused theorems in the current theory and all of its ancestors,
   312      excluding the theories thy_1 ... thy_n and all of their ancestors.
   313 
   314 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   315      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   316      their ancestors, excluding the theories thy_1 ... thy_n and all of
   317      their ancestors.
   318 
   319 In order to increase the readability of the list produced by
   320 unused_thms, theorems that have been created by a particular instance
   321 of a theory command such as 'inductive' or 'function' are considered
   322 to belong to the same "group", meaning that if at least one theorem in
   323 this group is used, the other theorems in the same group are no longer
   324 reported as unused.  Moreover, if all theorems in the group are
   325 unused, only one theorem in the group is displayed.
   326 
   327 Note that proof objects have to be switched on in order for
   328 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   329 usually the case when using Proof General with the default settings).
   330 
   331 * Authentic naming of facts disallows ad-hoc overwriting of previous
   332 theorems within the same name space.  INCOMPATIBILITY, need to remove
   333 duplicate fact bindings, or even accidental fact duplications.  Note
   334 that tools may maintain dynamically scoped facts systematically, using
   335 PureThy.add_thms_dynamic.
   336 
   337 * Command 'hide' now allows to hide from "fact" name space as well.
   338 
   339 * Eliminated destructive theorem database, simpset, claset, and
   340 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   341 update of theories within ML code.
   342 
   343 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   344 INCOMPATIBILITY, object-logics depending on former Pure require
   345 additional setup PureThy.old_appl_syntax_setup; object-logics
   346 depending on former CPure need to refer to Pure.
   347 
   348 * Commands 'use' and 'ML' are now purely functional, operating on
   349 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   350 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   351 INCOMPATIBILITY.
   352 
   353 * Command 'setup': discontinued implicit version with ML reference.
   354 
   355 * Instantiation target allows for simultaneous specification of class
   356 instance operations together with an instantiation proof.
   357 Type-checking phase allows to refer to class operations uniformly.
   358 See src/HOL/Complex/Complex.thy for an Isar example and
   359 src/HOL/Library/Eval.thy for an ML example.
   360 
   361 * Indexing of literal facts: be more serious about including only
   362 facts from the visible specification/proof context, but not the
   363 background context (locale etc.).  Affects `prop` notation and method
   364 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   365 situations.
   366 
   367 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   368 "(open)" option, which used to expose internal bound variables to the
   369 proof text.
   370 
   371 * Isar statements: removed obsolete case "rule_context".
   372 INCOMPATIBILITY, better use explicit fixes/assumes.
   373 
   374 * Locale proofs: default proof step now includes 'unfold_locales';
   375 hence 'proof' without argument may be used to unfold locale
   376 predicates.
   377 
   378 
   379 *** Document preparation ***
   380 
   381 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   382 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   383 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   384 spot); renamed link color from "darkblue" to "linkcolor" (default
   385 value unchanged, can be redefined via \definecolor); no longer sets
   386 "a4paper" option (unnecessary or even intrusive).
   387 
   388 * Antiquotation @{lemma A method} proves proposition A by the given
   389 method (either a method name or a method name plus (optional) method
   390 arguments in parentheses) and prints A just like @{prop A}.
   391 
   392 
   393 *** HOL ***
   394 
   395 * New primrec package.  Specification syntax conforms in style to
   396 definition/function/....  No separate induction rule is provided.  The
   397 "primrec" command distinguishes old-style and new-style specifications
   398 by syntax.  The former primrec package is now named OldPrimrecPackage.
   399 When adjusting theories, beware: constants stemming from new-style
   400 primrec specifications have authentic syntax.
   401 
   402 * Metis prover is now an order of magnitude faster, and also works
   403 with multithreading.
   404 
   405 * Metis: the maximum number of clauses that can be produced from a
   406 theorem is now given by the attribute max_clauses.  Theorems that
   407 exceed this number are ignored, with a warning printed.
   408 
   409 * Sledgehammer no longer produces structured proofs by default. To
   410 enable, declare [[sledgehammer_full = true]].  Attributes
   411 reconstruction_modulus, reconstruction_sorts renamed
   412 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   413 
   414 * Method "induct_scheme" derives user-specified induction rules
   415 from well-founded induction and completeness of patterns. This factors
   416 out some operations that are done internally by the function package
   417 and makes them available separately.  See
   418 src/HOL/ex/Induction_Scheme.thy for examples.
   419 
   420 * More flexible generation of measure functions for termination
   421 proofs: Measure functions can be declared by proving a rule of the
   422 form "is_measure f" and giving it the [measure_function] attribute.
   423 The "is_measure" predicate is logically meaningless (always true), and
   424 just guides the heuristic.  To find suitable measure functions, the
   425 termination prover sets up the goal "is_measure ?f" of the appropriate
   426 type and generates all solutions by prolog-style backwards proof using
   427 the declared rules.
   428 
   429 This setup also deals with rules like 
   430 
   431   "is_measure f ==> is_measure (list_size f)"
   432 
   433 which accommodates nested datatypes that recurse through lists.
   434 Similar rules are predeclared for products and option types.
   435 
   436 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   437 
   438   INCOMPATIBILITIES:
   439 
   440   - Definitions of overloaded constants on sets have to be replaced by
   441     definitions on => and bool.
   442 
   443   - Some definitions of overloaded operators on sets can now be proved
   444     using the definitions of the operators on => and bool.  Therefore,
   445     the following theorems have been renamed:
   446 
   447       subset_def   -> subset_eq
   448       psubset_def  -> psubset_eq
   449       set_diff_def -> set_diff_eq
   450       Compl_def    -> Compl_eq
   451       Sup_set_def  -> Sup_set_eq
   452       Inf_set_def  -> Inf_set_eq
   453       sup_set_def  -> sup_set_eq
   454       inf_set_def  -> inf_set_eq
   455 
   456   - Due to the incompleteness of the HO unification algorithm, some
   457     rules such as subst may require manual instantiation, if some of
   458     the unknowns in the rule is a set.
   459 
   460   - Higher order unification and forward proofs:
   461     The proof pattern
   462 
   463       have "P (S::'a set)" <...>
   464       then have "EX S. P S" ..
   465 
   466     no longer works (due to the incompleteness of the HO unification
   467     algorithm) and must be replaced by the pattern
   468 
   469       have "EX S. P S"
   470       proof
   471         show "P S" <...>
   472       qed
   473 
   474   - Calculational reasoning with subst (or similar rules):
   475     The proof pattern
   476 
   477       have "P (S::'a set)" <...>
   478       also have "S = T" <...>
   479       finally have "P T" .
   480 
   481     no longer works (for similar reasons as the previous example) and
   482     must be replaced by something like
   483 
   484       have "P (S::'a set)" <...>
   485       moreover have "S = T" <...>
   486       ultimately have "P T" by simp
   487 
   488   - Tactics or packages written in ML code:
   489     Code performing pattern matching on types via
   490 
   491       Type ("set", [T]) => ...
   492 
   493     must be rewritten. Moreover, functions like strip_type or
   494     binder_types no longer return the right value when applied to a
   495     type of the form
   496 
   497       T1 => ... => Tn => U => bool
   498 
   499     rather than
   500 
   501       T1 => ... => Tn => U set
   502 
   503 * Merged theories Wellfounded_Recursion, Accessible_Part and
   504 Wellfounded_Relations to theory Wellfounded.
   505 
   506 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   507 
   508 * Class finite no longer treats UNIV as class parameter.  Use class
   509 enum from theory Library/Enum instead to achieve a similar effect.
   510 INCOMPATIBILITY.
   511 
   512 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   513 and "Cons".  INCOMPATIBILITY.
   514 
   515 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   516 Potential INCOMPATIBILITY.
   517 
   518 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   519 injective_fst_snd removed, use split_eta and prod_eqI instead.
   520 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   521 
   522 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   523 the same name in theory Orderings:
   524 
   525   less_trans
   526   less_linear
   527   le_imp_less_or_eq
   528   le_less_trans
   529   less_le_trans
   530   less_not_sym
   531   less_asym
   532 
   533 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
   534 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
   535 and different variable names.
   536 
   537 * Library/Option_ord.thy: Canonical order on option type.
   538 
   539 * Library/RBT.thy: Red-black trees, an efficient implementation of
   540 finite maps.
   541 
   542 * Library/Countable.thy: Type class for countable types.
   543 
   544 * Theory Int: The representation of numerals has changed.  The infix
   545 operator BIT and the bit datatype with constructors B0 and B1 have
   546 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
   547 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
   548 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
   549 accordingly.
   550 
   551 * Theory Nat: definition of <= and < on natural numbers no longer
   552 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
   553 le_def and less_def have disappeared.  Consider lemmas not_less
   554 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
   555 
   556 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
   557 (whose purpose mainly is for various fold_set functionals) have been
   558 abandoned in favor of the existing algebraic classes
   559 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
   560 lower_semilattice (resp. upper_semilattice) and linorder.
   561 INCOMPATIBILITY.
   562 
   563 * Theory Transitive_Closure: induct and cases rules now declare proper
   564 case_names ("base" and "step").  INCOMPATIBILITY.
   565 
   566 * Theorem Inductive.lfp_ordinal_induct generalized to complete
   567 lattices.  The form set-specific version is available as
   568 Inductive.lfp_ordinal_induct_set.
   569 
   570 * Renamed theorems "power.simps" to "power_int.simps".
   571 INCOMPATIBILITY.
   572 
   573 * Class semiring_div provides basic abstract properties of semirings
   574 with division and modulo operations.  Subsumes former class dvd_mod.
   575 
   576 * Merged theories IntDef, Numeral and IntArith into unified theory
   577 Int.  INCOMPATIBILITY.
   578 
   579 * Theory Library/Code_Index: type "index" now represents natural
   580 numbers rather than integers.  INCOMPATIBILITY.
   581 
   582 * New class "uminus" with operation "uminus" (split of from class
   583 "minus" which now only has operation "minus", binary).
   584 INCOMPATIBILITY.
   585 
   586 * Constants "card", "internal_split", "option_map" now with authentic
   587 syntax.  INCOMPATIBILITY.
   588 
   589 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
   590 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
   591 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
   592 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
   593 Sup_set_def, le_def, less_def, option_map_def now with object
   594 equality.  INCOMPATIBILITY.
   595 
   596 * Records. Removed K_record, and replaced it by pure lambda term
   597 %x. c. The simplifier setup is now more robust against eta expansion.
   598 INCOMPATIBILITY: in cases explicitly referring to K_record.
   599 
   600 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
   601 
   602 * Library/ListVector: new theory of arithmetic vector operations.
   603 
   604 * Library/Order_Relation: new theory of various orderings as sets of
   605 pairs.  Defines preorders, partial orders, linear orders and
   606 well-orders on sets and on types.
   607 
   608 
   609 *** ZF ***
   610 
   611 * Renamed some theories to allow to loading both ZF and HOL in the
   612 same session:
   613 
   614   Datatype  -> Datatype_ZF
   615   Inductive -> Inductive_ZF
   616   Int       -> Int_ZF
   617   IntDiv    -> IntDiv_ZF
   618   Nat       -> Nat_ZF
   619   List      -> List_ZF
   620   Main      -> Main_ZF
   621 
   622 INCOMPATIBILITY: ZF theories that import individual theories below
   623 Main might need to be adapted.  Regular theory Main is still
   624 available, as trivial extension of Main_ZF.
   625 
   626 
   627 *** ML ***
   628 
   629 * ML within Isar: antiquotation @{const name} or @{const
   630 name(typargs)} produces statically-checked Const term.
   631 
   632 * Functor NamedThmsFun: data is available to the user as dynamic fact
   633 (of the same name).  Removed obsolete print command.
   634 
   635 * Removed obsolete "use_legacy_bindings" function.
   636 
   637 * The ``print mode'' is now a thread-local value derived from a global
   638 template (the former print_mode reference), thus access becomes
   639 non-critical.  The global print_mode reference is for session
   640 management only; user-code should use print_mode_value,
   641 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
   642 
   643 * Functions system/system_out provide a robust way to invoke external
   644 shell commands, with propagation of interrupts (requires Poly/ML 5.2).
   645 Do not use OS.Process.system etc. from the basis library!
   646 
   647 
   648 *** System ***
   649 
   650 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
   651 in accordance with Proof General 3.7, which prefers GNU emacs.
   652 
   653 * isatool tty runs Isabelle process with plain tty interaction;
   654 optional line editor may be specified via ISABELLE_LINE_EDITOR
   655 setting, the default settings attempt to locate "ledit" and "rlwrap".
   656 
   657 * isatool browser now works with Cygwin as well, using general
   658 "javapath" function defined in Isabelle process environment.
   659 
   660 * YXML notation provides a simple and efficient alternative to
   661 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
   662 isatool yxml as described in the Isabelle system manual.
   663 
   664 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
   665 provides general wrapper for managing an Isabelle process in a robust
   666 fashion, with ``cooked'' output from stdin/stderr.
   667 
   668 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
   669 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
   670 
   671 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
   672 way of changing the user's settings is via
   673 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
   674 script.
   675 
   676 * Multithreading.max_threads := 0 refers to the number of actual CPU
   677 cores of the underlying machine, which is a good starting point for
   678 optimal performance tuning.  The corresponding usedir option -M allows
   679 "max" as an alias for "0".  WARNING: does not work on certain versions
   680 of Mac OS (with Poly/ML 5.1).
   681 
   682 * isabelle-process: non-ML sessions are run with "nice", to reduce the
   683 adverse effect of Isabelle flooding interactive front-ends (notably
   684 ProofGeneral / XEmacs).
   685 
   686 
   687 
   688 New in Isabelle2007 (November 2007)
   689 -----------------------------------
   690 
   691 *** General ***
   692 
   693 * More uniform information about legacy features, notably a
   694 warning/error of "Legacy feature: ...", depending on the state of the
   695 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
   696 legacy features will disappear eventually.
   697 
   698 * Theory syntax: the header format ``theory A = B + C:'' has been
   699 discontinued in favour of ``theory A imports B C begin''.  Use isatool
   700 fixheaders to convert existing theory files.  INCOMPATIBILITY.
   701 
   702 * Theory syntax: the old non-Isar theory file format has been
   703 discontinued altogether.  Note that ML proof scripts may still be used
   704 with Isar theories; migration is usually quite simple with the ML
   705 function use_legacy_bindings.  INCOMPATIBILITY.
   706 
   707 * Theory syntax: some popular names (e.g. 'class', 'declaration',
   708 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
   709 quotes.
   710 
   711 * Theory loader: be more serious about observing the static theory
   712 header specifications (including optional directories), but not the
   713 accidental file locations of previously successful loads.  The strict
   714 update policy of former update_thy is now already performed by
   715 use_thy, so the former has been removed; use_thys updates several
   716 theories simultaneously, just as 'imports' within a theory header
   717 specification, but without merging the results.  Potential
   718 INCOMPATIBILITY: may need to refine theory headers and commands
   719 ROOT.ML which depend on load order.
   720 
   721 * Theory loader: optional support for content-based file
   722 identification, instead of the traditional scheme of full physical
   723 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
   724 (cf. the system manual).  The new scheme allows to work with
   725 non-finished theories in persistent session images, such that source
   726 files may be moved later on without requiring reloads.
   727 
   728 * Theory loader: old-style ML proof scripts being *attached* to a thy
   729 file (with the same base name as the theory) are considered a legacy
   730 feature, which will disappear eventually. Even now, the theory loader
   731 no longer maintains dependencies on such files.
   732 
   733 * Syntax: the scope for resolving ambiguities via type-inference is
   734 now limited to individual terms, instead of whole simultaneous
   735 specifications as before. This greatly reduces the complexity of the
   736 syntax module and improves flexibility by separating parsing and
   737 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
   738 'fixes' etc.) are required in rare situations.
   739 
   740 * Syntax: constants introduced by new-style packages ('definition',
   741 'abbreviation' etc.) are passed through the syntax module in
   742 ``authentic mode''. This means that associated mixfix annotations
   743 really stick to such constants, independently of potential name space
   744 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
   745 trees are represented slightly differently, may need to adapt syntax
   746 translations accordingly. Use CONST marker in 'translations' and
   747 @{const_syntax} antiquotation in 'parse_translation' etc.
   748 
   749 * Legacy goal package: reduced interface to the bare minimum required
   750 to keep existing proof scripts running.  Most other user-level
   751 functions are now part of the OldGoals structure, which is *not* open
   752 by default (consider isatool expandshort before open OldGoals).
   753 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
   754 these tend to cause confusion about the actual goal (!) context being
   755 used here, which is not necessarily the same as the_context().
   756 
   757 * Command 'find_theorems': supports "*" wild-card in "name:"
   758 criterion; "with_dups" option.  Certain ProofGeneral versions might
   759 support a specific search form (see ProofGeneral/CHANGES).
   760 
   761 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
   762 by default, which means that "prems" (and also "fixed variables") are
   763 suppressed from proof state output.  Note that the ProofGeneral
   764 settings mechanism allows to change and save options persistently, but
   765 older versions of Isabelle will fail to start up if a negative prems
   766 limit is imposed.
   767 
   768 * Local theory targets may be specified by non-nested blocks of
   769 ``context/locale/class ... begin'' followed by ``end''.  The body may
   770 contain definitions, theorems etc., including any derived mechanism
   771 that has been implemented on top of these primitives.  This concept
   772 generalizes the existing ``theorem (in ...)'' towards more versatility
   773 and scalability.
   774 
   775 * Proof General interface: proper undo of final 'end' command;
   776 discontinued Isabelle/classic mode (ML proof scripts).
   777 
   778 
   779 *** Document preparation ***
   780 
   781 * Added antiquotation @{theory name} which prints the given name,
   782 after checking that it refers to a valid ancestor theory in the
   783 current context.
   784 
   785 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   786 check the given source text as ML type/structure, printing verbatim.
   787 
   788 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   789 "c args == rhs" given in the current context.  (Any number of
   790 arguments may be given on the LHS.)
   791 
   792 
   793 *** Pure ***
   794 
   795 * The 'class' package offers a combination of axclass and locale to
   796 achieve Haskell-like type classes in Isabelle.  Definitions and
   797 theorems within a class context produce both relative results (with
   798 implicit parameters according to the locale context), and polymorphic
   799 constants with qualified polymorphism (according to the class
   800 context).  Within the body context of a 'class' target, a separate
   801 syntax layer ("user space type system") takes care of converting
   802 between global polymorphic consts and internal locale representation.
   803 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   804 "isatool doc classes" provides a tutorial.
   805 
   806 * Generic code generator framework allows to generate executable
   807 code for ML and Haskell (including Isabelle classes).  A short usage
   808 sketch:
   809 
   810     internal compilation:
   811         export_code <list of constants (term syntax)> in SML
   812     writing SML code to a file:
   813         export_code <list of constants (term syntax)> in SML <filename>
   814     writing OCaml code to a file:
   815         export_code <list of constants (term syntax)> in OCaml <filename>
   816     writing Haskell code to a bunch of files:
   817         export_code <list of constants (term syntax)> in Haskell <filename>
   818 
   819     evaluating closed propositions to True/False using code generation:
   820         method ``eval''
   821 
   822 Reasonable default setup of framework in HOL.
   823 
   824 Theorem attributs for selecting and transforming function equations theorems:
   825 
   826     [code fun]:        select a theorem as function equation for a specific constant
   827     [code fun del]:    deselect a theorem as function equation for a specific constant
   828     [code inline]:     select an equation theorem for unfolding (inlining) in place
   829     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   830 
   831 User-defined serializations (target in {SML, OCaml, Haskell}):
   832 
   833     code_const <and-list of constants (term syntax)>
   834       {(target) <and-list of const target syntax>}+
   835 
   836     code_type <and-list of type constructors>
   837       {(target) <and-list of type target syntax>}+
   838 
   839     code_instance <and-list of instances>
   840       {(target)}+
   841         where instance ::= <type constructor> :: <class>
   842 
   843     code_class <and_list of classes>
   844       {(target) <and-list of class target syntax>}+
   845         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   846 
   847 code_instance and code_class only are effective to target Haskell.
   848 
   849 For example usage see src/HOL/ex/Codegenerator.thy and
   850 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   851 generation from Isabelle/HOL theories is available via "isatool doc
   852 codegen".
   853 
   854 * Code generator: consts in 'consts_code' Isar commands are now
   855 referred to by usual term syntax (including optional type
   856 annotations).
   857 
   858 * Command 'no_translations' removes translation rules from theory
   859 syntax.
   860 
   861 * Overloaded definitions are now actually checked for acyclic
   862 dependencies.  The overloading scheme is slightly more general than
   863 that of Haskell98, although Isabelle does not demand an exact
   864 correspondence to type class and instance declarations.
   865 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   866 exotic versions of overloading -- at the discretion of the user!
   867 
   868 Polymorphic constants are represented via type arguments, i.e. the
   869 instantiation that matches an instance against the most general
   870 declaration given in the signature.  For example, with the declaration
   871 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   872 as c(nat).  Overloading is essentially simultaneous structural
   873 recursion over such type arguments.  Incomplete specification patterns
   874 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   875 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   876 Command 'print_theory' outputs the normalized system of recursive
   877 equations, see section "definitions".
   878 
   879 * Configuration options are maintained within the theory or proof
   880 context (with name and type bool/int/string), providing a very simple
   881 interface to a poor-man's version of general context data.  Tools may
   882 declare options in ML (e.g. using Attrib.config_int) and then refer to
   883 these values using Config.get etc.  Users may change options via an
   884 associated attribute of the same name.  This form of context
   885 declaration works particularly well with commands 'declare' or
   886 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   887 very easy to avoid global references, which would not observe Isar
   888 toplevel undo/redo and fail to work with multithreading.
   889 
   890 Various global ML references of Pure and HOL have been turned into
   891 configuration options:
   892 
   893   Unify.search_bound		unify_search_bound
   894   Unify.trace_bound		unify_trace_bound
   895   Unify.trace_simp		unify_trace_simp
   896   Unify.trace_types		unify_trace_types
   897   Simplifier.simp_depth_limit	simp_depth_limit
   898   Blast.depth_limit		blast_depth_limit
   899   DatatypeProp.dtK		datatype_distinctness_limit
   900   fast_arith_neq_limit  	fast_arith_neq_limit
   901   fast_arith_split_limit	fast_arith_split_limit
   902 
   903 * Named collections of theorems may be easily installed as context
   904 data using the functor NamedThmsFun (see also
   905 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   906 attributes; there is also a toplevel print command.  This facility is
   907 just a common case of general context data, which is the preferred way
   908 for anything more complex than just a list of facts in canonical
   909 order.
   910 
   911 * Isar: command 'declaration' augments a local theory by generic
   912 declaration functions written in ML.  This enables arbitrary content
   913 being added to the context, depending on a morphism that tells the
   914 difference of the original declaration context wrt. the application
   915 context encountered later on.
   916 
   917 * Isar: proper interfaces for simplification procedures.  Command
   918 'simproc_setup' declares named simprocs (with match patterns, and body
   919 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   920 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   921 
   922 * Isar: an extra pair of brackets around attribute declarations
   923 abbreviates a theorem reference involving an internal dummy fact,
   924 which will be ignored later --- only the effect of the attribute on
   925 the background context will persist.  This form of in-place
   926 declarations is particularly useful with commands like 'declare' and
   927 'using', for example ``have A using [[simproc a]] by simp''.
   928 
   929 * Isar: method "assumption" (and implicit closing of subproofs) now
   930 takes simple non-atomic goal assumptions into account: after applying
   931 an assumption as a rule the resulting subgoals are solved by atomic
   932 assumption steps.  This is particularly useful to finish 'obtain'
   933 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   934 without referring to the original premise "!!x. P x ==> thesis" in the
   935 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   936 more permissive.
   937 
   938 * Isar: implicit use of prems from the Isar proof context is
   939 considered a legacy feature.  Common applications like ``have A .''
   940 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   941 referencing facts explicitly here improves readability and
   942 maintainability of proof texts.
   943 
   944 * Isar: improper proof element 'guess' is like 'obtain', but derives
   945 the obtained context from the course of reasoning!  For example:
   946 
   947   assume "EX x y. A x & B y"   -- "any previous fact"
   948   then guess x and y by clarify
   949 
   950 This technique is potentially adventurous, depending on the facts and
   951 proof tools being involved here.
   952 
   953 * Isar: known facts from the proof context may be specified as literal
   954 propositions, using ASCII back-quote syntax.  This works wherever
   955 named facts used to be allowed so far, in proof commands, proof
   956 methods, attributes etc.  Literal facts are retrieved from the context
   957 according to unification of type and term parameters.  For example,
   958 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   959 theorems in the current context, then these are valid literal facts:
   960 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   961 
   962 There is also a proof method "fact" which does the same composition
   963 for explicit goal states, e.g. the following proof texts coincide with
   964 certain special cases of literal facts:
   965 
   966   have "A" by fact                 ==  note `A`
   967   have "A ==> B" by fact           ==  note `A ==> B`
   968   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   969   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   970 
   971 * Isar: ":" (colon) is no longer a symbolic identifier character in
   972 outer syntax.  Thus symbolic identifiers may be used without
   973 additional white space in declarations like this: ``assume *: A''.
   974 
   975 * Isar: 'print_facts' prints all local facts of the current context,
   976 both named and unnamed ones.
   977 
   978 * Isar: 'def' now admits simultaneous definitions, e.g.:
   979 
   980   def x == "t" and y == "u"
   981 
   982 * Isar: added command 'unfolding', which is structurally similar to
   983 'using', but affects both the goal state and facts by unfolding given
   984 rewrite rules.  Thus many occurrences of the 'unfold' method or
   985 'unfolded' attribute may be replaced by first-class proof text.
   986 
   987 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   988 and command 'unfolding' now all support object-level equalities
   989 (potentially conditional).  The underlying notion of rewrite rule is
   990 analogous to the 'rule_format' attribute, but *not* that of the
   991 Simplifier (which is usually more generous).
   992 
   993 * Isar: the new attribute [rotated n] (default n = 1) rotates the
   994 premises of a theorem by n. Useful in conjunction with drule.
   995 
   996 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   997 method expression within a sandbox consisting of the first N
   998 sub-goals, which need to exist.  For example, ``simp_all [3]''
   999 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1000 simplifies all new goals that emerge from applying rule foo to the
  1001 originally first one.
  1002 
  1003 * Isar: schematic goals are no longer restricted to higher-order
  1004 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1005 expected.
  1006 
  1007 * Isar: the conclusion of a long theorem statement is now either
  1008 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1009 (essentially a disjunction of cases with local parameters and
  1010 assumptions).  The latter allows to express general elimination rules
  1011 adequately; in this notation common elimination rules look like this:
  1012 
  1013   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1014     assumes "EX x. P x"
  1015     obtains x where "P x"
  1016 
  1017   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1018     assumes "A & B"
  1019     obtains A and B
  1020 
  1021   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1022     assumes "A | B"
  1023     obtains
  1024       A
  1025     | B
  1026 
  1027 The subsequent classical rules even refer to the formal "thesis"
  1028 explicitly:
  1029 
  1030   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1031     obtains "~ thesis"
  1032 
  1033   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1034     obtains "thesis ==> something"
  1035 
  1036 The actual proof of an 'obtains' statement is analogous to that of the
  1037 Isar proof element 'obtain', only that there may be several cases.
  1038 Optional case names may be specified in parentheses; these will be
  1039 available both in the present proof and as annotations in the
  1040 resulting rule, for later use with the 'cases' method (cf. attribute
  1041 case_names).
  1042 
  1043 * Isar: the assumptions of a long theorem statement are available as
  1044 "assms" fact in the proof context.  This is more appropriate than the
  1045 (historical) "prems", which refers to all assumptions of the current
  1046 context, including those from the target locale, proof body etc.
  1047 
  1048 * Isar: 'print_statement' prints theorems from the current theory or
  1049 proof context in long statement form, according to the syntax of a
  1050 top-level lemma.
  1051 
  1052 * Isar: 'obtain' takes an optional case name for the local context
  1053 introduction rule (default "that").
  1054 
  1055 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1056 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1057 to occur.
  1058 
  1059 * Pure: syntax "CONST name" produces a fully internalized constant
  1060 according to the current context.  This is particularly useful for
  1061 syntax translations that should refer to internal constant
  1062 representations independently of name spaces.
  1063 
  1064 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1065 instead of "FOO ". This allows multiple binder declarations to coexist
  1066 in the same context.  INCOMPATIBILITY.
  1067 
  1068 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1069 primitive that also works in a locale context (both for constants and
  1070 fixed variables). Type declaration and internal syntactic representation
  1071 of given constants retrieved from the context. Likewise, the
  1072 'no_notation' command allows to remove given syntax annotations from the
  1073 current context.
  1074 
  1075 * Isar/locales: new derived specification elements 'axiomatization',
  1076 'definition', 'abbreviation', which support type-inference, admit
  1077 object-level specifications (equality, equivalence).  See also the
  1078 isar-ref manual.  Examples:
  1079 
  1080   axiomatization
  1081     eq  (infix "===" 50) where
  1082     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1083 
  1084   definition "f x y = x + y + 1"
  1085   definition g where "g x = f x x"
  1086 
  1087   abbreviation
  1088     neq  (infix "=!=" 50) where
  1089     "x =!= y == ~ (x === y)"
  1090 
  1091 These specifications may be also used in a locale context.  Then the
  1092 constants being introduced depend on certain fixed parameters, and the
  1093 constant name is qualified by the locale base name.  An internal
  1094 abbreviation takes care for convenient input and output, making the
  1095 parameters implicit and using the original short name.  See also
  1096 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1097 entities from a monomorphic theory.
  1098 
  1099 Presently, abbreviations are only available 'in' a target locale, but
  1100 not inherited by general import expressions.  Also note that
  1101 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1102 'translations' in common applications.  The "no_abbrevs" print mode
  1103 prevents folding of abbreviations in term output.
  1104 
  1105 Concrete syntax is attached to specified constants in internal form,
  1106 independently of name spaces.  The parse tree representation is
  1107 slightly different -- use 'notation' instead of raw 'syntax', and
  1108 'translations' with explicit "CONST" markup to accommodate this.
  1109 
  1110 * Pure/Isar: unified syntax for new-style specification mechanisms
  1111 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1112 full type inference and dummy patterns ("_").  For example:
  1113 
  1114   definition "K x _ = x"
  1115 
  1116   inductive conj for A B
  1117   where "A ==> B ==> conj A B"
  1118 
  1119 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1120 the current context.  Print mode "no_abbrevs" prevents inversion of
  1121 abbreviations on output.
  1122 
  1123 * Isar/locales: improved parameter handling: use of locales "var" and
  1124 "struct" no longer necessary; - parameter renamings are no longer
  1125 required to be injective.  For example, this allows to define
  1126 endomorphisms as locale endom = homom mult mult h.
  1127 
  1128 * Isar/locales: changed the way locales with predicates are defined.
  1129 Instead of accumulating the specification, the imported expression is
  1130 now an interpretation.  INCOMPATIBILITY: different normal form of
  1131 locale expressions.  In particular, in interpretations of locales with
  1132 predicates, goals repesenting already interpreted fragments are not
  1133 removed automatically.  Use methods `intro_locales' and
  1134 `unfold_locales'; see below.
  1135 
  1136 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1137 provide backward reasoning on locales predicates.  The methods are
  1138 aware of interpretations and discharge corresponding goals.
  1139 `intro_locales' is less aggressive then `unfold_locales' and does not
  1140 unfold predicates to assumptions.
  1141 
  1142 * Isar/locales: the order in which locale fragments are accumulated
  1143 has changed.  This enables to override declarations from fragments due
  1144 to interpretations -- for example, unwanted simp rules.
  1145 
  1146 * Isar/locales: interpretation in theories and proof contexts has been
  1147 extended.  One may now specify (and prove) equations, which are
  1148 unfolded in interpreted theorems.  This is useful for replacing
  1149 defined concepts (constants depending on locale parameters) by
  1150 concepts already existing in the target context.  Example:
  1151 
  1152   interpretation partial_order ["op <= :: [int, int] => bool"]
  1153     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1154 
  1155 Typically, the constant `partial_order.less' is created by a
  1156 definition specification element in the context of locale
  1157 partial_order.
  1158 
  1159 * Method "induct": improved internal context management to support
  1160 local fixes and defines on-the-fly. Thus explicit meta-level
  1161 connectives !!  and ==> are rarely required anymore in inductive goals
  1162 (using object-logic connectives for this purpose has been long
  1163 obsolete anyway). Common proof patterns are explained in
  1164 src/HOL/Induct/Common_Patterns.thy, see also
  1165 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1166 examples.
  1167 
  1168 * Method "induct": improved handling of simultaneous goals. Instead of
  1169 introducing object-level conjunction, the statement is now split into
  1170 several conclusions, while the corresponding symbolic cases are nested
  1171 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1172 see src/HOL/Induct/Common_Patterns.thy, for example.
  1173 
  1174 * Method "induct": mutual induction rules are now specified as a list
  1175 of rule sharing the same induction cases. HOL packages usually provide
  1176 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1177 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1178 mutual induction rules differently, i.e. like this:
  1179 
  1180   (induct rule: foo_bar.inducts)
  1181   (induct set: foo bar)
  1182   (induct pred: foo bar)
  1183   (induct type: foo bar)
  1184 
  1185 The ML function ProjectRule.projections turns old-style rules into the
  1186 new format.
  1187 
  1188 * Method "coinduct": dual of induction, see
  1189 src/HOL/Library/Coinductive_List.thy for various examples.
  1190 
  1191 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1192 considered a legacy feature.
  1193 
  1194 * Attribute "symmetric" produces result with standardized schematic
  1195 variables (index 0).  Potential INCOMPATIBILITY.
  1196 
  1197 * Simplifier: by default the simplifier trace only shows top level
  1198 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1199 default. Thus there is less danger of being flooded by the trace. The
  1200 trace indicates where parts have been suppressed.
  1201   
  1202 * Provers/classical: removed obsolete classical version of elim_format
  1203 attribute; classical elim/dest rules are now treated uniformly when
  1204 manipulating the claset.
  1205 
  1206 * Provers/classical: stricter checks to ensure that supplied intro,
  1207 dest and elim rules are well-formed; dest and elim rules must have at
  1208 least one premise.
  1209 
  1210 * Provers/classical: attributes dest/elim/intro take an optional
  1211 weight argument for the rule (just as the Pure versions).  Weights are
  1212 ignored by automated tools, but determine the search order of single
  1213 rule steps.
  1214 
  1215 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1216 where the body does not mention the bound variable.  Note that dummy
  1217 patterns implicitly depend on their context of bounds, which makes
  1218 "{_. _}" match any set comprehension as expected.  Potential
  1219 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1220 constant "_idtdummy" in the binding position.
  1221 
  1222 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1223 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1224 for example "A -> B" => "Pi A (%_. B)".
  1225 
  1226 * Pure: 'class_deps' command visualizes the subclass relation, using
  1227 the graph browser tool.
  1228 
  1229 * Pure: 'print_theory' now suppresses certain internal declarations by
  1230 default; use '!' option for full details.
  1231 
  1232 
  1233 *** HOL ***
  1234 
  1235 * Method "metis" proves goals by applying the Metis general-purpose
  1236 resolution prover (see also http://gilith.com/software/metis/).
  1237 Examples are in the directory MetisExamples.  WARNING: the
  1238 Isabelle/HOL-Metis integration does not yet work properly with
  1239 multi-threading.
  1240   
  1241 * Command 'sledgehammer' invokes external automatic theorem provers as
  1242 background processes.  It generates calls to the "metis" method if
  1243 successful. These can be pasted into the proof.  Users do not have to
  1244 wait for the automatic provers to return.  WARNING: does not really
  1245 work with multi-threading.
  1246 
  1247 * New "auto_quickcheck" feature tests outermost goal statements for
  1248 potential counter-examples.  Controlled by ML references
  1249 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1250 5000 milliseconds).  Fails silently if statements is outside of
  1251 executable fragment, or any other codgenerator problem occurs.
  1252 
  1253 * New constant "undefined" with axiom "undefined x = undefined".
  1254 
  1255 * Added class "HOL.eq", allowing for code generation with polymorphic
  1256 equality.
  1257 
  1258 * Some renaming of class constants due to canonical name prefixing in
  1259 the new 'class' package:
  1260 
  1261     HOL.abs ~> HOL.abs_class.abs
  1262     HOL.divide ~> HOL.divide_class.divide
  1263     0 ~> HOL.zero_class.zero
  1264     1 ~> HOL.one_class.one
  1265     op + ~> HOL.plus_class.plus
  1266     op - ~> HOL.minus_class.minus
  1267     uminus ~> HOL.minus_class.uminus
  1268     op * ~> HOL.times_class.times
  1269     op < ~> HOL.ord_class.less
  1270     op <= > HOL.ord_class.less_eq
  1271     Nat.power ~> Power.power_class.power
  1272     Nat.size ~> Nat.size_class.size
  1273     Numeral.number_of ~> Numeral.number_class.number_of
  1274     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1275     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1276     Orderings.min ~> Orderings.ord_class.min
  1277     Orderings.max ~> Orderings.ord_class.max
  1278     Divides.op div ~> Divides.div_class.div
  1279     Divides.op mod ~> Divides.div_class.mod
  1280     Divides.op dvd ~> Divides.div_class.dvd
  1281 
  1282 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1283 
  1284 a) User-defined constants using any of the names "plus", "minus",
  1285 "times", "less" or "less_eq". The standard syntax translations for
  1286 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1287 names.
  1288 
  1289 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1290 INCOMPATIBILITY: use more specific names.
  1291 
  1292 c) Permutative equations (e.g. "a + b = b + a")
  1293 Since the change of names also changes the order of terms, permutative
  1294 rewrite rules may get applied in a different order. Experience shows
  1295 that this is rarely the case (only two adaptions in the whole Isabelle
  1296 distribution).  INCOMPATIBILITY: rewrite proofs
  1297 
  1298 d) ML code directly refering to constant names
  1299 This in general only affects hand-written proof tactics, simprocs and
  1300 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1301 Consider using @{const_name} antiquotation.
  1302 
  1303 * New class "default" with associated constant "default".
  1304 
  1305 * Function "sgn" is now overloaded and available on int, real, complex
  1306 (and other numeric types), using class "sgn".  Two possible defs of
  1307 sgn are given as equational assumptions in the classes sgn_if and
  1308 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1309 INCOMPATIBILITY.
  1310 
  1311 * Locale "partial_order" now unified with class "order" (cf. theory
  1312 Orderings), added parameter "less".  INCOMPATIBILITY.
  1313 
  1314 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1315 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1316 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1317 
  1318 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1319 changed order of proof goals in instance proofs.
  1320 
  1321 * The transitivity reasoner for partial and linear orders is set up
  1322 for classes "order" and "linorder".  Instances of the reasoner are available
  1323 in all contexts importing or interpreting the corresponding locales.
  1324 Method "order" invokes the reasoner separately; the reasoner
  1325 is also integrated with the Simplifier as a solver.  Diagnostic
  1326 command 'print_orders' shows the available instances of the reasoner
  1327 in the current context.
  1328 
  1329 * Localized monotonicity predicate in theory "Orderings"; integrated
  1330 lemmas max_of_mono and min_of_mono with this predicate.
  1331 INCOMPATIBILITY.
  1332 
  1333 * Formulation of theorem "dense" changed slightly due to integration
  1334 with new class dense_linear_order.
  1335 
  1336 * Uniform lattice theory development in HOL.
  1337 
  1338     constants "meet" and "join" now named "inf" and "sup"
  1339     constant "Meet" now named "Inf"
  1340 
  1341     classes "meet_semilorder" and "join_semilorder" now named
  1342       "lower_semilattice" and "upper_semilattice"
  1343     class "lorder" now named "lattice"
  1344     class "comp_lat" now named "complete_lattice"
  1345 
  1346     Instantiation of lattice classes allows explicit definitions
  1347     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1348 
  1349   INCOMPATIBILITY.  Theorem renames:
  1350 
  1351     meet_left_le            ~> inf_le1
  1352     meet_right_le           ~> inf_le2
  1353     join_left_le            ~> sup_ge1
  1354     join_right_le           ~> sup_ge2
  1355     meet_join_le            ~> inf_sup_ord
  1356     le_meetI                ~> le_infI
  1357     join_leI                ~> le_supI
  1358     le_meet                 ~> le_inf_iff
  1359     le_join                 ~> ge_sup_conv
  1360     meet_idempotent         ~> inf_idem
  1361     join_idempotent         ~> sup_idem
  1362     meet_comm               ~> inf_commute
  1363     join_comm               ~> sup_commute
  1364     meet_leI1               ~> le_infI1
  1365     meet_leI2               ~> le_infI2
  1366     le_joinI1               ~> le_supI1
  1367     le_joinI2               ~> le_supI2
  1368     meet_assoc              ~> inf_assoc
  1369     join_assoc              ~> sup_assoc
  1370     meet_left_comm          ~> inf_left_commute
  1371     meet_left_idempotent    ~> inf_left_idem
  1372     join_left_comm          ~> sup_left_commute
  1373     join_left_idempotent    ~> sup_left_idem
  1374     meet_aci                ~> inf_aci
  1375     join_aci                ~> sup_aci
  1376     le_def_meet             ~> le_iff_inf
  1377     le_def_join             ~> le_iff_sup
  1378     join_absorp2            ~> sup_absorb2
  1379     join_absorp1            ~> sup_absorb1
  1380     meet_absorp1            ~> inf_absorb1
  1381     meet_absorp2            ~> inf_absorb2
  1382     meet_join_absorp        ~> inf_sup_absorb
  1383     join_meet_absorp        ~> sup_inf_absorb
  1384     distrib_join_le         ~> distrib_sup_le
  1385     distrib_meet_le         ~> distrib_inf_le
  1386 
  1387     add_meet_distrib_left   ~> add_inf_distrib_left
  1388     add_join_distrib_left   ~> add_sup_distrib_left
  1389     is_join_neg_meet        ~> is_join_neg_inf
  1390     is_meet_neg_join        ~> is_meet_neg_sup
  1391     add_meet_distrib_right  ~> add_inf_distrib_right
  1392     add_join_distrib_right  ~> add_sup_distrib_right
  1393     add_meet_join_distribs  ~> add_sup_inf_distribs
  1394     join_eq_neg_meet        ~> sup_eq_neg_inf
  1395     meet_eq_neg_join        ~> inf_eq_neg_sup
  1396     add_eq_meet_join        ~> add_eq_inf_sup
  1397     meet_0_imp_0            ~> inf_0_imp_0
  1398     join_0_imp_0            ~> sup_0_imp_0
  1399     meet_0_eq_0             ~> inf_0_eq_0
  1400     join_0_eq_0             ~> sup_0_eq_0
  1401     neg_meet_eq_join        ~> neg_inf_eq_sup
  1402     neg_join_eq_meet        ~> neg_sup_eq_inf
  1403     join_eq_if              ~> sup_eq_if
  1404 
  1405     mono_meet               ~> mono_inf
  1406     mono_join               ~> mono_sup
  1407     meet_bool_eq            ~> inf_bool_eq
  1408     join_bool_eq            ~> sup_bool_eq
  1409     meet_fun_eq             ~> inf_fun_eq
  1410     join_fun_eq             ~> sup_fun_eq
  1411     meet_set_eq             ~> inf_set_eq
  1412     join_set_eq             ~> sup_set_eq
  1413     meet1_iff               ~> inf1_iff
  1414     meet2_iff               ~> inf2_iff
  1415     meet1I                  ~> inf1I
  1416     meet2I                  ~> inf2I
  1417     meet1D1                 ~> inf1D1
  1418     meet2D1                 ~> inf2D1
  1419     meet1D2                 ~> inf1D2
  1420     meet2D2                 ~> inf2D2
  1421     meet1E                  ~> inf1E
  1422     meet2E                  ~> inf2E
  1423     join1_iff               ~> sup1_iff
  1424     join2_iff               ~> sup2_iff
  1425     join1I1                 ~> sup1I1
  1426     join2I1                 ~> sup2I1
  1427     join1I1                 ~> sup1I1
  1428     join2I2                 ~> sup1I2
  1429     join1CI                 ~> sup1CI
  1430     join2CI                 ~> sup2CI
  1431     join1E                  ~> sup1E
  1432     join2E                  ~> sup2E
  1433 
  1434     is_meet_Meet            ~> is_meet_Inf
  1435     Meet_bool_def           ~> Inf_bool_def
  1436     Meet_fun_def            ~> Inf_fun_def
  1437     Meet_greatest           ~> Inf_greatest
  1438     Meet_lower              ~> Inf_lower
  1439     Meet_set_def            ~> Inf_set_def
  1440 
  1441     Sup_def                 ~> Sup_Inf
  1442     Sup_bool_eq             ~> Sup_bool_def
  1443     Sup_fun_eq              ~> Sup_fun_def
  1444     Sup_set_eq              ~> Sup_set_def
  1445 
  1446     listsp_meetI            ~> listsp_infI
  1447     listsp_meet_eq          ~> listsp_inf_eq
  1448 
  1449     meet_min                ~> inf_min
  1450     join_max                ~> sup_max
  1451 
  1452 * Added syntactic class "size"; overloaded constant "size" now has
  1453 type "'a::size ==> bool"
  1454 
  1455 * Internal reorganisation of `size' of datatypes: size theorems
  1456 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1457 simplification rules by default!); theorems "prod.size" now named
  1458 "*.size".
  1459 
  1460 * Class "div" now inherits from class "times" rather than "type".
  1461 INCOMPATIBILITY.
  1462 
  1463 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1464 Linorder etc.  have disappeared; operations defined in terms of
  1465 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1466 
  1467 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1468 
  1469 * HOL-Word: New extensive library and type for generic, fixed size
  1470 machine words, with arithemtic, bit-wise, shifting and rotating
  1471 operations, reflection into int, nat, and bool lists, automation for
  1472 linear arithmetic (by automatic reflection into nat or int), including
  1473 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1474 arithmetic type classes, supporting automatic simplification of
  1475 numerals on all operations.
  1476 
  1477 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1478 
  1479 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1480 
  1481 * Code generator library theories:
  1482   - Code_Integer represents HOL integers by big integer literals in target
  1483     languages.
  1484   - Code_Char represents HOL characters by character literals in target
  1485     languages.
  1486   - Code_Char_chr like Code_Char, but also offers treatment of character
  1487     codes; includes Code_Integer.
  1488   - Executable_Set allows to generate code for finite sets using lists.
  1489   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1490     denominator).
  1491   - Executable_Real implements a subset of real numbers, namly those
  1492     representable by rational numbers.
  1493   - Efficient_Nat implements natural numbers by integers, which in general will
  1494     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1495     includes Code_Integer.
  1496   - Code_Index provides an additional datatype index which is mapped to
  1497     target-language built-in integers.
  1498   - Code_Message provides an additional datatype message_string which is isomorphic to
  1499     strings; messages are mapped to target-language strings.
  1500 
  1501 * New package for inductive predicates
  1502 
  1503   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1504 
  1505     inductive
  1506       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1507       for z_1 :: U_1 and ... and z_n :: U_m
  1508     where
  1509       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1510     | ...
  1511 
  1512   with full support for type-inference, rather than
  1513 
  1514     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1515 
  1516     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1517     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1518 
  1519     inductive "s z_1 ... z_m"
  1520     intros
  1521       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1522       ...
  1523 
  1524   For backward compatibility, there is a wrapper allowing inductive
  1525   sets to be defined with the new package via
  1526 
  1527     inductive_set
  1528       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1529       for z_1 :: U_1 and ... and z_n :: U_m
  1530     where
  1531       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1532     | ...
  1533 
  1534   or
  1535 
  1536     inductive_set
  1537       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1538       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1539       for z_1 :: U_1 and ... and z_n :: U_m
  1540     where
  1541       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1542     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1543     | ...
  1544 
  1545   if the additional syntax "p ..." is required.
  1546 
  1547   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1548   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1549 
  1550   INCOMPATIBILITIES:
  1551 
  1552   - Since declaration and definition of inductive sets or predicates
  1553     is no longer separated, abbreviations involving the newly
  1554     introduced sets or predicates must be specified together with the
  1555     introduction rules after the 'where' keyword (see above), rather
  1556     than before the actual inductive definition.
  1557 
  1558   - The variables in induction and elimination rules are now
  1559     quantified in the order of their occurrence in the introduction
  1560     rules, rather than in alphabetical order. Since this may break
  1561     some proofs, these proofs either have to be repaired, e.g. by
  1562     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1563     statements of the form
  1564 
  1565       case (rule_i a_i_1 ... a_i_{k_i})
  1566 
  1567     or the old order of quantification has to be restored by explicitly adding
  1568     meta-level quantifiers in the introduction rules, i.e.
  1569 
  1570       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  1571 
  1572   - The format of the elimination rules is now
  1573 
  1574       p z_1 ... z_m x_1 ... x_n ==>
  1575         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1576         ==> ... ==> P
  1577 
  1578     for predicates and
  1579 
  1580       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1581         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1582         ==> ... ==> P
  1583 
  1584     for sets rather than
  1585 
  1586       x : s z_1 ... z_m ==>
  1587         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1588         ==> ... ==> P
  1589 
  1590     This may require terms in goals to be expanded to n-tuples
  1591     (e.g. using case_tac or simplification with the split_paired_all
  1592     rule) before the above elimination rule is applicable.
  1593 
  1594   - The elimination or case analysis rules for (mutually) inductive
  1595     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1596     list of rules "p_1_..._p_k.elims" is no longer available.
  1597 
  1598 * New package "function"/"fun" for general recursive functions,
  1599 supporting mutual and nested recursion, definitions in local contexts,
  1600 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1601 for small examples, and the separate tutorial on the function
  1602 package. The old recdef "package" is still available as before, but
  1603 users are encouraged to use the new package.
  1604 
  1605 * Method "lexicographic_order" automatically synthesizes termination
  1606 relations as lexicographic combinations of size measures. 
  1607 
  1608 * Case-expressions allow arbitrary constructor-patterns (including
  1609 "_") and take their order into account, like in functional
  1610 programming.  Internally, this is translated into nested
  1611 case-expressions; missing cases are added and mapped to the predefined
  1612 constant "undefined". In complicated cases printing may no longer show
  1613 the original input but the internal form. Lambda-abstractions allow
  1614 the same form of pattern matching: "% pat1 => e1 | ..." is an
  1615 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  1616 variable.
  1617 
  1618 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  1619 is an abbreviation for "of_nat :: nat => int". The simplification
  1620 rules for "of_nat" have been changed to work like "int" did
  1621 previously.  Potential INCOMPATIBILITY:
  1622   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  1623   - of_nat_diff and of_nat_mult are no longer default simp rules
  1624 
  1625 * Method "algebra" solves polynomial equations over (semi)rings using
  1626 Groebner bases. The (semi)ring structure is defined by locales and the
  1627 tool setup depends on that generic context. Installing the method for
  1628 a specific type involves instantiating the locale and possibly adding
  1629 declarations for computation on the coefficients.  The method is
  1630 already instantiated for natural numbers and for the axiomatic class
  1631 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  1632 CALCULEMUS 2007 for the general principles underlying this
  1633 architecture of context-aware proof-tools.
  1634 
  1635 * Method "ferrack" implements quantifier elimination over
  1636 special-purpose dense linear orders using locales (analogous to
  1637 "algebra"). The method is already installed for class
  1638 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  1639 rat, etc.
  1640 
  1641 * Former constant "List.op @" now named "List.append".  Use ML
  1642 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  1643 circumvent possible incompatibilities when working on ML level.
  1644 
  1645 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1646 
  1647 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1648 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1649 
  1650 * New syntax for Haskell-like list comprehension (input only), eg.
  1651 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1652 
  1653 * The special syntax for function "filter" has changed from [x :
  1654 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1655 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1656 
  1657 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1658 defined on nat only, as an abbreviation for [a..<Suc b]
  1659 INCOMPATIBILITY.
  1660 
  1661 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1662 
  1663 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1664 
  1665 * New lemma collection field_simps (an extension of ring_simps) for
  1666 manipulating (in)equations involving division. Multiplies with all
  1667 denominators that can be proved to be non-zero (in equations) or
  1668 positive/negative (in inequations).
  1669 
  1670 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1671 have been improved and renamed to ring_simps, group_simps and
  1672 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1673 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1674 
  1675 * Theory Library/Commutative_Ring: switched from recdef to function
  1676 package; constants add, mul, pow now curried.  Infix syntax for
  1677 algebraic operations.
  1678 
  1679 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1680 INCOMPATIBILITY.
  1681 
  1682 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1683 INCOMPATIBILITY.
  1684 
  1685 * HOL/records: generalised field-update to take a function on the
  1686 field rather than the new value: r(|A := x|) is translated to A_update
  1687 (K x) r The K-combinator that is internally used is called K_record.
  1688 INCOMPATIBILITY: Usage of the plain update functions has to be
  1689 adapted.
  1690  
  1691 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1692 * x = 0, which are required for a semiring.  Richer structures do not
  1693 inherit from semiring_0 anymore, because this property is a theorem
  1694 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1695 there is more to prove, but this is mostly trivial.
  1696 
  1697 * Class "recpower" is generalized to arbitrary monoids, not just
  1698 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1699 commutativity or semiring properties additionally.
  1700 
  1701 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1702 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1703 better use 'abbreviation'.
  1704 
  1705 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1706 
  1707 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1708 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1709 significant changes for setting up numeral syntax for types:
  1710   - New constants Numeral.pred and Numeral.succ instead
  1711       of former Numeral.bin_pred and Numeral.bin_succ.
  1712   - Use integer operations instead of bin_add, bin_mult and so on.
  1713   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1714   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1715 
  1716 See src/HOL/Integ/IntArith.thy for an example setup.
  1717 
  1718 * Command 'normal_form' computes the normal form of a term that may
  1719 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1720 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1721 heavy-duty computations because the functions are compiled to ML
  1722 first.  Correspondingly, a method "normalization" is provided.  See
  1723 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1724 
  1725 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1726 25 like -->); output depends on the "iff" print_mode, the default is
  1727 "A = B" (with priority 50).
  1728 
  1729 * Relations less (<) and less_eq (<=) are also available on type bool.
  1730 Modified syntax to disallow nesting without explicit parentheses,
  1731 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1732 INCOMPATIBILITY.
  1733 
  1734 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1735 
  1736 * Relation composition operator "op O" now has precedence 75 and binds
  1737 stronger than union and intersection. INCOMPATIBILITY.
  1738 
  1739 * The old set interval syntax "{m..n(}" (and relatives) has been
  1740 removed.  Use "{m..<n}" (and relatives) instead.
  1741 
  1742 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1743 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1744 ``declare [[simproc del: neq]]''.
  1745 
  1746 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1747 True/False.
  1748 
  1749 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1750 
  1751 * Theorem setsum_mult renamed to setsum_right_distrib.
  1752 
  1753 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1754 ``rule'' method.
  1755 
  1756 * Reimplemented methods "sat" and "satx", with several improvements:
  1757 goals no longer need to be stated as "<prems> ==> False", equivalences
  1758 (i.e. "=" on type bool) are handled, variable names of the form
  1759 "lit_<n>" are no longer reserved, significant speedup.
  1760 
  1761 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1762 zChaff is still supported as well.
  1763 
  1764 * 'inductive' and 'datatype': provide projections of mutual rules,
  1765 bundled as foo_bar.inducts;
  1766 
  1767 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1768 Library.
  1769 
  1770 * Library: moved theory Accessible_Part to main HOL.
  1771 
  1772 * Library: added theory Coinductive_List of potentially infinite lists
  1773 as greatest fixed-point.
  1774 
  1775 * Library: added theory AssocList which implements (finite) maps as
  1776 association lists.
  1777 
  1778 * Method "evaluation" solves goals (i.e. a boolean expression)
  1779 efficiently by compiling it to ML.  The goal is "proved" (via an
  1780 oracle) if it evaluates to True.
  1781 
  1782 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1783 also when invoked by the simplifier.  This results in the Simplifier
  1784 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1785 Configuration option fast_arith_split_limit=0 recovers the old
  1786 behavior.
  1787 
  1788 * Support for hex (0x20) and binary (0b1001) numerals.
  1789 
  1790 * New method: reify eqs (t), where eqs are equations for an
  1791 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1792 parameter, computes a term s::'b and a list xs::'a list and proves the
  1793 theorem I xs s = t. This is also known as reification or quoting. The
  1794 resulting theorem is applied to the subgoal to substitute t with I xs
  1795 s.  If t is omitted, the subgoal itself is reified.
  1796 
  1797 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1798 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1799 where f is supposed to be a computable function (in the sense of code
  1800 generattion). The method uses reify to compute s and xs as above then
  1801 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1802 r and finally gets the theorem t = r, which is again applied to the
  1803 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1804 
  1805 * Reflection: Automatic reification now handels binding, an example is
  1806 available in src/HOL/ex/ReflectionEx.thy
  1807 
  1808 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  1809 command 'statespace' that is similar to 'record', but introduces an
  1810 abstract specification based on the locale infrastructure instead of
  1811 HOL types.  This leads to extra flexibility in composing state spaces,
  1812 in particular multiple inheritance and renaming of components.
  1813 
  1814 
  1815 *** HOL-Complex ***
  1816 
  1817 * Hyperreal: Functions root and sqrt are now defined on negative real
  1818 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1819 Nonnegativity side conditions have been removed from many lemmas, so
  1820 that more subgoals may now be solved by simplification; potential
  1821 INCOMPATIBILITY.
  1822 
  1823 * Real: new type classes formalize real normed vector spaces and
  1824 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1825 and norm :: 'a => real.
  1826 
  1827 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1828 reals into other types. The overloaded constant Reals :: 'a set is now
  1829 defined as range of_real; potential INCOMPATIBILITY.
  1830 
  1831 * Real: proper support for ML code generation, including 'quickcheck'.
  1832 Reals are implemented as arbitrary precision rationals.
  1833 
  1834 * Hyperreal: Several constants that previously worked only for the
  1835 reals have been generalized, so they now work over arbitrary vector
  1836 spaces. Type annotations may need to be added in some cases; potential
  1837 INCOMPATIBILITY.
  1838 
  1839   Infinitesimal  :: ('a::real_normed_vector) star set
  1840   HFinite        :: ('a::real_normed_vector) star set
  1841   HInfinite      :: ('a::real_normed_vector) star set
  1842   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1843   monad          :: ('a::real_normed_vector) star => 'a star set
  1844   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1845   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1846   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1847   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1848   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1849   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1850   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1851   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1852   sgn            :: 'a::real_normed_vector => 'a
  1853   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1854 
  1855 * Complex: Some complex-specific constants are now abbreviations for
  1856 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1857 hnorm.  Other constants have been entirely removed in favor of the
  1858 polymorphic versions (INCOMPATIBILITY):
  1859 
  1860   approx        <-- capprox
  1861   HFinite       <-- CFinite
  1862   HInfinite     <-- CInfinite
  1863   Infinitesimal <-- CInfinitesimal
  1864   monad         <-- cmonad
  1865   galaxy        <-- cgalaxy
  1866   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1867   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1868   (ns)deriv     <-- (ns)cderiv
  1869 
  1870 
  1871 *** HOL-Algebra ***
  1872 
  1873 * Formalisation of ideals and the quotient construction over rings.
  1874 
  1875 * Order and lattice theory no longer based on records.
  1876 INCOMPATIBILITY.
  1877 
  1878 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1879 greatest_closed.  INCOMPATIBILITY.
  1880 
  1881 * Method algebra is now set up via an attribute.  For examples see
  1882 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1883 of algebraic structures.
  1884 
  1885 * Renamed theory CRing to Ring.
  1886 
  1887 
  1888 *** HOL-Nominal ***
  1889 
  1890 * Substantial, yet incomplete support for nominal datatypes (binding
  1891 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  1892 src/HOL/Nominal/Examples.  Prospective users should consult
  1893 http://isabelle.in.tum.de/nominal/
  1894 
  1895 
  1896 *** ML ***
  1897 
  1898 * ML basics: just one true type int, which coincides with IntInf.int
  1899 (even on SML/NJ).
  1900 
  1901 * ML within Isar: antiquotations allow to embed statically-checked
  1902 formal entities in the source, referring to the context available at
  1903 compile-time.  For example:
  1904 
  1905 ML {* @{sort "{zero,one}"} *}
  1906 ML {* @{typ "'a => 'b"} *}
  1907 ML {* @{term "%x. x"} *}
  1908 ML {* @{prop "x == y"} *}
  1909 ML {* @{ctyp "'a => 'b"} *}
  1910 ML {* @{cterm "%x. x"} *}
  1911 ML {* @{cprop "x == y"} *}
  1912 ML {* @{thm asm_rl} *}
  1913 ML {* @{thms asm_rl} *}
  1914 ML {* @{type_name c} *}
  1915 ML {* @{type_syntax c} *}
  1916 ML {* @{const_name c} *}
  1917 ML {* @{const_syntax c} *}
  1918 ML {* @{context} *}
  1919 ML {* @{theory} *}
  1920 ML {* @{theory Pure} *}
  1921 ML {* @{theory_ref} *}
  1922 ML {* @{theory_ref Pure} *}
  1923 ML {* @{simpset} *}
  1924 ML {* @{claset} *}
  1925 ML {* @{clasimpset} *}
  1926 
  1927 The same works for sources being ``used'' within an Isar context.
  1928 
  1929 * ML in Isar: improved error reporting; extra verbosity with
  1930 ML_Context.trace enabled.
  1931 
  1932 * Pure/General/table.ML: the join operations now works via exceptions
  1933 DUP/SAME instead of type option. This is simpler in simple cases, and
  1934 admits slightly more efficient complex applications.
  1935 
  1936 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1937 use Context.generic instead of just theory.
  1938 
  1939 * Pure: datatype Context.generic joins theory/Proof.context and
  1940 provides some facilities for code that works in either kind of
  1941 context, notably GenericDataFun for uniform theory and proof data.
  1942 
  1943 * Pure: simplified internal attribute type, which is now always
  1944 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  1945 local (Proof.context) attributes have been discontinued, while
  1946 minimizing code duplication. Thm.rule_attribute and
  1947 Thm.declaration_attribute build canonical attributes; see also structure
  1948 Context for further operations on Context.generic, notably
  1949 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  1950 declarations and definitions.
  1951 
  1952 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1953 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1954 init only required for impure data. INCOMPATIBILITY: empty really need
  1955 to be empty (no dependencies on theory content!)
  1956 
  1957 * Pure/kernel: consts certification ignores sort constraints given in
  1958 signature declarations. (This information is not relevant to the
  1959 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  1960 potential INCOMPATIBILITY.
  1961 
  1962 * Pure: axiomatic type classes are now purely definitional, with
  1963 explicit proofs of class axioms and super class relations performed
  1964 internally. See Pure/axclass.ML for the main internal interfaces --
  1965 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1966 AxClass.axiomatize_class/classrel/arity supersede
  1967 Sign.add_classes/classrel/arities.
  1968 
  1969 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1970 global/local versions on theory vs. Proof.context have been
  1971 discontinued; Attrib.syntax and Method.syntax have been adapted
  1972 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1973 attributes, methods, etc.
  1974 
  1975 * Pure: several functions of signature "... -> theory -> theory * ..."
  1976 have been reoriented to "... -> theory -> ... * theory" in order to
  1977 allow natural usage in combination with the ||>, ||>>, |-> and
  1978 fold_map combinators.
  1979 
  1980 * Pure: official theorem names (closed derivations) and additional
  1981 comments (tags) are now strictly separate.  Name hints -- which are
  1982 maintained as tags -- may be attached any time without affecting the
  1983 derivation.
  1984 
  1985 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1986 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1987 achieve the old behaviour.
  1988 
  1989 * Pure: the "Goal" constant is now called "prop", supporting a
  1990 slightly more general idea of ``protecting'' meta-level rule
  1991 statements.
  1992 
  1993 * Pure: Logic.(un)varify only works in a global context, which is now
  1994 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1995 Logic.legacy_(un)varify as temporary workaround.
  1996 
  1997 * Pure: structure Name provides scalable operations for generating
  1998 internal variable names, notably Name.variants etc.  This replaces
  1999 some popular functions from term.ML:
  2000 
  2001   Term.variant		->  Name.variant
  2002   Term.variantlist	->  Name.variant_list
  2003   Term.invent_names	->  Name.invent_list
  2004 
  2005 Note that low-level renaming rarely occurs in new code -- operations
  2006 from structure Variable are used instead (see below).
  2007 
  2008 * Pure: structure Variable provides fundamental operations for proper
  2009 treatment of fixed/schematic variables in a context.  For example,
  2010 Variable.import introduces fixes for schematics of given facts and
  2011 Variable.export reverses the effect (up to renaming) -- this replaces
  2012 various freeze_thaw operations.
  2013 
  2014 * Pure: structure Goal provides simple interfaces for
  2015 init/conclude/finish and tactical prove operations (replacing former
  2016 Tactic.prove).  Goal.prove is the canonical way to prove results
  2017 within a given context; Goal.prove_global is a degraded version for
  2018 theory level goals, including a global Drule.standard.  Note that
  2019 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2020 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2021 in a locale context).
  2022 
  2023 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2024 and type checking (Syntax.check_term etc.), with common combinations
  2025 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2026 which are considered legacy and await removal.
  2027 
  2028 * Pure/Syntax: generic interfaces for type unchecking
  2029 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2030 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2031 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2032 available for convenience, but refer to the very same operations using
  2033 a mere theory instead of a full context.
  2034 
  2035 * Isar: simplified treatment of user-level errors, using exception
  2036 ERROR of string uniformly.  Function error now merely raises ERROR,
  2037 without any side effect on output channels.  The Isar toplevel takes
  2038 care of proper display of ERROR exceptions.  ML code may use plain
  2039 handle/can/try; cat_error may be used to concatenate errors like this:
  2040 
  2041   ... handle ERROR msg => cat_error msg "..."
  2042 
  2043 Toplevel ML code (run directly or through the Isar toplevel) may be
  2044 embedded into the Isar toplevel with exception display/debug like
  2045 this:
  2046 
  2047   Isar.toplevel (fn () => ...)
  2048 
  2049 INCOMPATIBILITY, removed special transform_error facilities, removed
  2050 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2051 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2052 -- use plain ERROR instead.
  2053 
  2054 * Isar: theory setup now has type (theory -> theory), instead of a
  2055 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2056 
  2057 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2058 ProofContext.debug/verbose flags.
  2059 
  2060 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2061 theory before entering a proof state.  Transactions now always see a
  2062 quasi-functional intermediate checkpoint, both in interactive and
  2063 batch mode.
  2064 
  2065 * Isar: simplified interfaces for outer syntax.  Renamed
  2066 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2067 OuterSyntax.add_parsers -- this functionality is now included in
  2068 OuterSyntax.command etc.  INCOMPATIBILITY.
  2069 
  2070 * Simplifier: the simpset of a running simplification process now
  2071 contains a proof context (cf. Simplifier.the_context), which is the
  2072 very context that the initial simpset has been retrieved from (by
  2073 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2074 (solver, looper etc.) may depend on arbitrary proof data.
  2075 
  2076 * Simplifier.inherit_context inherits the proof context (plus the
  2077 local bounds) of the current simplification process; any simproc
  2078 etc. that calls the Simplifier recursively should do this!  Removed
  2079 former Simplifier.inherit_bounds, which is already included here --
  2080 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2081 specify an explicit context using Simplifier.context/theory_context.
  2082 
  2083 * Simplifier/Classical Reasoner: more abstract interfaces
  2084 change_simpset/claset for modifying the simpset/claset reference of a
  2085 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2086 INCOMPATIBILITY.
  2087 
  2088 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2089 "Trueprop" etc.
  2090 
  2091 
  2092 *** System ***
  2093 
  2094 * settings: the default heap location within ISABELLE_HOME_USER now
  2095 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2096 Isabelle installations.
  2097 
  2098 * isabelle-process: option -S (secure mode) disables some critical
  2099 operations, notably runtime compilation and evaluation of ML source
  2100 code.
  2101 
  2102 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2103 
  2104 * Support for parallel execution, using native multicore support of
  2105 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2106 independent theories, according to the given theory header
  2107 specifications. The maximum number of worker threads is specified via
  2108 usedir option -M or the "max-threads" setting in Proof General. A
  2109 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2110 to 6 on a 8-core machine.  User-code needs to observe certain
  2111 guidelines for thread-safe programming, see appendix A in the Isar
  2112 Implementation manual.
  2113 
  2114 
  2115 
  2116 New in Isabelle2005 (October 2005)
  2117 ----------------------------------
  2118 
  2119 *** General ***
  2120 
  2121 * Theory headers: the new header syntax for Isar theories is
  2122 
  2123   theory <name>
  2124   imports <theory1> ... <theoryN>
  2125   uses <file1> ... <fileM>
  2126   begin
  2127 
  2128 where the 'uses' part is optional.  The previous syntax
  2129 
  2130   theory <name> = <theory1> + ... + <theoryN>:
  2131 
  2132 will disappear in the next release.  Use isatool fixheaders to convert
  2133 existing theory files.  Note that there is no change in ancient
  2134 non-Isar theories now, but these will disappear soon.
  2135 
  2136 * Theory loader: parent theories can now also be referred to via
  2137 relative and absolute paths.
  2138 
  2139 * Command 'find_theorems' searches for a list of criteria instead of a
  2140 list of constants. Known criteria are: intro, elim, dest, name:string,
  2141 simp:term, and any term. Criteria can be preceded by '-' to select
  2142 theorems that do not match. Intro, elim, dest select theorems that
  2143 match the current goal, name:s selects theorems whose fully qualified
  2144 name contain s, and simp:term selects all simplification rules whose
  2145 lhs match term.  Any other term is interpreted as pattern and selects
  2146 all theorems matching the pattern. Available in ProofGeneral under
  2147 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2148 
  2149   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2150 
  2151 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2152 matching the current goal as introduction rule and not having "HOL."
  2153 in their name (i.e. not being defined in theory HOL).
  2154 
  2155 * Command 'thms_containing' has been discontinued in favour of
  2156 'find_theorems'; INCOMPATIBILITY.
  2157 
  2158 * Communication with Proof General is now 8bit clean, which means that
  2159 Unicode text in UTF-8 encoding may be used within theory texts (both
  2160 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2161 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2162 
  2163   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2164   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2165 
  2166 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2167 Classical Reasoner.  Typical big applications run around 2 times
  2168 faster.
  2169 
  2170 
  2171 *** Document preparation ***
  2172 
  2173 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2174 of raw sources.  Only those symbols that do not require additional
  2175 LaTeX packages (depending on comments in isabellesym.sty) are
  2176 displayed properly, everything else is left verbatim.  isatool display
  2177 and isatool print are used as front ends (these are subject to the
  2178 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2179 
  2180 * Command tags control specific markup of certain regions of text,
  2181 notably folding and hiding.  Predefined tags include "theory" (for
  2182 theory begin and end), "proof" for proof commands, and "ML" for
  2183 commands involving ML code; the additional tags "visible" and
  2184 "invisible" are unused by default.  Users may give explicit tag
  2185 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2186 interpretation of tags is determined by the LaTeX job during document
  2187 preparation: see option -V of isatool usedir, or options -n and -t of
  2188 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2189 \isadroptag.
  2190 
  2191 Several document versions may be produced at the same time via isatool
  2192 usedir (the generated index.html will link all of them).  Typical
  2193 specifications include ''-V document=theory,proof,ML'' to present
  2194 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2195 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2196 these parts without any formal replacement text.  The Isabelle site
  2197 default settings produce ''document'' and ''outline'' versions as
  2198 specified above.
  2199 
  2200 * Several new antiquotations:
  2201 
  2202   @{term_type term} prints a term with its type annotated;
  2203 
  2204   @{typeof term} prints the type of a term;
  2205 
  2206   @{const const} is the same as @{term const}, but checks that the
  2207   argument is a known logical constant;
  2208 
  2209   @{term_style style term} and @{thm_style style thm} print a term or
  2210   theorem applying a "style" to it
  2211 
  2212   @{ML text}
  2213 
  2214 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2215 definitions, equations, inequations etc., 'concl' printing only the
  2216 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2217 to print the specified premise.  TermStyle.add_style provides an ML
  2218 interface for introducing further styles.  See also the "LaTeX Sugar"
  2219 document practical applications.  The ML antiquotation prints
  2220 type-checked ML expressions verbatim.
  2221 
  2222 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2223 and 'text' support optional locale specification '(in loc)', which
  2224 specifies the default context for interpreting antiquotations.  For
  2225 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2226 
  2227 * Option 'locale=NAME' of antiquotations specifies an alternative
  2228 context interpreting the subsequent argument.  For example: @{thm
  2229 [locale=lattice] inf_assoc}.
  2230 
  2231 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2232 a proof context.
  2233 
  2234 * Proper output of antiquotations for theory commands involving a
  2235 proof context (such as 'locale' or 'theorem (in loc) ...').
  2236 
  2237 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2238 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2239 
  2240 * isatool usedir: new option -C (default true) controls whether option
  2241 -D should include a copy of the original document directory; -C false
  2242 prevents unwanted effects such as copying of administrative CVS data.
  2243 
  2244 
  2245 *** Pure ***
  2246 
  2247 * Considerably improved version of 'constdefs' command.  Now performs
  2248 automatic type-inference of declared constants; additional support for
  2249 local structure declarations (cf. locales and HOL records), see also
  2250 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2251 sequential dependencies of definitions within a single 'constdefs'
  2252 section; moreover, the declared name needs to be an identifier.  If
  2253 all fails, consider to fall back on 'consts' and 'defs' separately.
  2254 
  2255 * Improved indexed syntax and implicit structures.  First of all,
  2256 indexed syntax provides a notational device for subscripted
  2257 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2258 expressions.  Secondly, in a local context with structure
  2259 declarations, number indexes \<^sub>n or the empty index (default
  2260 number 1) refer to a certain fixed variable implicitly; option
  2261 show_structs controls printing of implicit structures.  Typical
  2262 applications of these concepts involve record types and locales.
  2263 
  2264 * New command 'no_syntax' removes grammar declarations (and
  2265 translations) resulting from the given syntax specification, which is
  2266 interpreted in the same manner as for the 'syntax' command.
  2267 
  2268 * 'Advanced' translation functions (parse_translation etc.) may depend
  2269 on the signature of the theory context being presently used for
  2270 parsing/printing, see also isar-ref manual.
  2271 
  2272 * Improved 'oracle' command provides a type-safe interface to turn an
  2273 ML expression of type theory -> T -> term into a primitive rule of
  2274 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2275 is already included here); see also FOL/ex/IffExample.thy;
  2276 INCOMPATIBILITY.
  2277 
  2278 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2279 before); "cI" is no longer bound, use "c.intro" instead.
  2280 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2281 axclasses vs. locales.
  2282 
  2283 * Improved internal renaming of symbolic identifiers -- attach primes
  2284 instead of base 26 numbers.
  2285 
  2286 * New flag show_question_marks controls printing of leading question
  2287 marks in schematic variable names.
  2288 
  2289 * In schematic variable names, *any* symbol following \<^isub> or
  2290 \<^isup> is now treated as part of the base name.  For example, the
  2291 following works without printing of awkward ".0" indexes:
  2292 
  2293   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2294     by simp
  2295 
  2296 * Inner syntax includes (*(*nested*) comments*).
  2297 
  2298 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2299 annotations as "(00...)".
  2300 
  2301 * Clear separation of logical types and nonterminals, where the latter
  2302 may only occur in 'syntax' specifications or type abbreviations.
  2303 Before that distinction was only partially implemented via type class
  2304 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2305 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2306 exotic syntax specifications may require further adaption
  2307 (e.g. Cube/Cube.thy).
  2308 
  2309 * Removed obsolete type class "logic", use the top sort {} instead.
  2310 Note that non-logical types should be declared as 'nonterminals'
  2311 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2312 specifications.
  2313 
  2314 * Attributes 'induct' and 'cases': type or set names may now be
  2315 locally fixed variables as well.
  2316 
  2317 * Simplifier: can now control the depth to which conditional rewriting
  2318 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2319 Limit.
  2320 
  2321 * Simplifier: simplification procedures may now take the current
  2322 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2323 interface), which is very useful for calling the Simplifier
  2324 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2325 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2326 low-level mk_simproc no longer applies Logic.varify internally, to
  2327 allow for use in a context of fixed variables.
  2328 
  2329 * thin_tac now works even if the assumption being deleted contains !!
  2330 or ==>.  More generally, erule now works even if the major premise of
  2331 the elimination rule contains !! or ==>.
  2332 
  2333 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2334 
  2335 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2336 from Pure, which contains all common declarations already.  Both
  2337 theories are defined via plain Isabelle/Isar .thy files.
  2338 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2339 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2340 use isatool fixcpure to adapt your theory and ML sources.
  2341 
  2342 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2343 selections of theorems in named facts via index ranges.
  2344 
  2345 * 'print_theorems': in theory mode, really print the difference
  2346 wrt. the last state (works for interactive theory development only),
  2347 in proof mode print all local facts (cf. 'print_facts');
  2348 
  2349 * 'hide': option '(open)' hides only base names.
  2350 
  2351 * More efficient treatment of intermediate checkpoints in interactive
  2352 theory development.
  2353 
  2354 * Code generator is now invoked via code_module (incremental code
  2355 generation) and code_library (modular code generation, ML structures
  2356 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2357 must be quoted when used as identifiers.
  2358 
  2359 * New 'value' command for reading, evaluating and printing terms using
  2360 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2361 quoted when used as identifier.
  2362 
  2363 
  2364 *** Locales ***
  2365 
  2366 * New commands for the interpretation of locale expressions in
  2367 theories (1), locales (2) and proof contexts (3).  These generate
  2368 proof obligations from the expression specification.  After the
  2369 obligations have been discharged, theorems of the expression are added
  2370 to the theory, target locale or proof context.  The synopsis of the
  2371 commands is a follows:
  2372 
  2373   (1) interpretation expr inst
  2374   (2) interpretation target < expr
  2375   (3) interpret expr inst
  2376 
  2377 Interpretation in theories and proof contexts require a parameter
  2378 instantiation of terms from the current context.  This is applied to
  2379 specifications and theorems of the interpreted expression.
  2380 Interpretation in locales only permits parameter renaming through the
  2381 locale expression.  Interpretation is smart in that interpretations
  2382 that are active already do not occur in proof obligations, neither are
  2383 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2384 inspect active interpretations of a particular locale.  For details,
  2385 see the Isar Reference manual.  Examples can be found in
  2386 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2387 
  2388 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2389 'interpret' instead.
  2390 
  2391 * New context element 'constrains' for adding type constraints to
  2392 parameters.
  2393 
  2394 * Context expressions: renaming of parameters with syntax
  2395 redeclaration.
  2396 
  2397 * Locale declaration: 'includes' disallowed.
  2398 
  2399 * Proper static binding of attribute syntax -- i.e. types / terms /
  2400 facts mentioned as arguments are always those of the locale definition
  2401 context, independently of the context of later invocations.  Moreover,
  2402 locale operations (renaming and type / term instantiation) are applied
  2403 to attribute arguments as expected.
  2404 
  2405 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2406 actual attributes; rare situations may require Attrib.attribute to
  2407 embed those attributes into Attrib.src that lack concrete syntax.
  2408 Attribute implementations need to cooperate properly with the static
  2409 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2410 Attrib.XXX_thm etc. already do the right thing without further
  2411 intervention.  Only unusual applications -- such as "where" or "of"
  2412 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2413 on the context and the facts involved -- may have to assign parsed
  2414 values to argument tokens explicitly.
  2415 
  2416 * Changed parameter management in theorem generation for long goal
  2417 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2418 theorem statement in rare situations.
  2419 
  2420 * Locale inspection command 'print_locale' omits notes elements.  Use
  2421 'print_locale!' to have them included in the output.
  2422 
  2423 
  2424 *** Provers ***
  2425 
  2426 * Provers/hypsubst.ML: improved version of the subst method, for
  2427 single-step rewriting: it now works in bound variable contexts. New is
  2428 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2429 rewrite a different subterm than the original subst method, which is
  2430 still available as 'simplesubst'.
  2431 
  2432 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2433 and quasi orders.
  2434 
  2435 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2436 reflexive-transitive closure of relations.
  2437 
  2438 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2439 limit (previously hard-coded with a value of 20) user-definable.
  2440 
  2441 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2442 is peformed already.  Object-logics merely need to finish their
  2443 initial simpset configuration as before.  INCOMPATIBILITY.
  2444 
  2445 
  2446 *** HOL ***
  2447 
  2448 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2449 
  2450   syntax (epsilon)
  2451     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2452 
  2453 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2454 and x-symbol; use option '-m epsilon' to get it actually printed.
  2455 Moreover, the mathematically important symbolic identifier \<epsilon>
  2456 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2457 
  2458 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2459 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2460 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2461 support corresponding Isar calculations.
  2462 
  2463 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2464 instead of ":".
  2465 
  2466 * theory SetInterval: changed the syntax for open intervals:
  2467 
  2468   Old       New
  2469   {..n(}    {..<n}
  2470   {)n..}    {n<..}
  2471   {m..n(}   {m..<n}
  2472   {)m..n}   {m<..n}
  2473   {)m..n(}  {m<..<n}
  2474 
  2475 The old syntax is still supported but will disappear in the next
  2476 release.  For conversion use the following Emacs search and replace
  2477 patterns (these are not perfect but work quite well):
  2478 
  2479   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2480   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2481 
  2482 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2483 equalities in commutative rings; method 'algebra' provides a generic
  2484 interface.
  2485 
  2486 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2487 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2488 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2489 be a tuple pattern.
  2490 
  2491 Some new syntax forms are available:
  2492 
  2493   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2494   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2495   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2496   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2497 
  2498 The latter form "\<Sum>x < k. e" used to be based on a separate
  2499 function "Summation", which has been discontinued.
  2500 
  2501 * theory Finite_Set: in structured induction proofs, the insert case
  2502 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2503 (insert F x)'.
  2504 
  2505 * The 'refute' command has been extended to support a much larger
  2506 fragment of HOL, including axiomatic type classes, constdefs and
  2507 typedefs, inductive datatypes and recursion.
  2508 
  2509 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2510 Requires zChaff with proof generation to be installed.  See
  2511 HOL/ex/SAT_Examples.thy for examples.
  2512 
  2513 * Datatype induction via method 'induct' now preserves the name of the
  2514 induction variable. For example, when proving P(xs::'a list) by
  2515 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2516 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2517 in unstructured proof scripts.
  2518 
  2519 * Reworked implementation of records.  Improved scalability for
  2520 records with many fields, avoiding performance problems for type
  2521 inference. Records are no longer composed of nested field types, but
  2522 of nested extension types. Therefore the record type only grows linear
  2523 in the number of extensions and not in the number of fields.  The
  2524 top-level (users) view on records is preserved.  Potential
  2525 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2526 old record representation. The type generated for a record is called
  2527 <record_name>_ext_type.
  2528 
  2529 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2530 proofs triggered by a record definition or a simproc (if
  2531 quick_and_dirty is enabled).  Definitions of large records can take
  2532 quite long.
  2533 
  2534 New simproc record_upd_simproc for simplification of multiple record
  2535 updates enabled by default.  Moreover, trivial updates are also
  2536 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2537 occasionally, since simplification is more powerful by default.
  2538 
  2539 * typedef: proper support for polymorphic sets, which contain extra
  2540 type-variables in the term.
  2541 
  2542 * Simplifier: automatically reasons about transitivity chains
  2543 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2544 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2545 old proofs break occasionally as simplification may now solve more
  2546 goals than previously.
  2547 
  2548 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2549 present.  Works for all partial orders (class "order"), in particular
  2550 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2551 just like y <= x.
  2552 
  2553 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2554 bound variable or a constant then the let is unfolded.  Otherwise
  2555 first a is simplified to b, and then f b is simplified to g. If
  2556 possible we abstract b from g arriving at "let x = b in h x",
  2557 otherwise we unfold the let and arrive at g.  The simproc can be
  2558 enabled/disabled by the reference use_let_simproc.  Potential
  2559 INCOMPATIBILITY since simplification is more powerful by default.
  2560 
  2561 * Classical reasoning: the meson method now accepts theorems as arguments.
  2562 
  2563 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2564 jobs to provide advice on the provability of subgoals.
  2565 
  2566 * Theory OrderedGroup and Ring_and_Field: various additions and
  2567 improvements to faciliate calculations involving equalities and
  2568 inequalities.
  2569 
  2570 The following theorems have been eliminated or modified
  2571 (INCOMPATIBILITY):
  2572 
  2573   abs_eq             now named abs_of_nonneg
  2574   abs_of_ge_0        now named abs_of_nonneg
  2575   abs_minus_eq       now named abs_of_nonpos
  2576   imp_abs_id         now named abs_of_nonneg
  2577   imp_abs_neg_id     now named abs_of_nonpos
  2578   mult_pos           now named mult_pos_pos
  2579   mult_pos_le        now named mult_nonneg_nonneg
  2580   mult_pos_neg_le    now named mult_nonneg_nonpos
  2581   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2582   mult_neg           now named mult_neg_neg
  2583   mult_neg_le        now named mult_nonpos_nonpos
  2584 
  2585 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2586      
  2587      zero_le_square
  2588      not_square_less_zero 
  2589 
  2590   The following lemmas have been deleted from Real/RealPow:
  2591   
  2592      realpow_zero_zero
  2593      realpow_two
  2594      realpow_less
  2595      zero_le_power
  2596      realpow_two_le
  2597      abs_realpow_two
  2598      realpow_two_abs     
  2599 
  2600 * Theory Parity: added rules for simplifying exponents.
  2601 
  2602 * Theory List:
  2603 
  2604 The following theorems have been eliminated or modified
  2605 (INCOMPATIBILITY):
  2606 
  2607   list_all_Nil       now named list_all.simps(1)
  2608   list_all_Cons      now named list_all.simps(2)
  2609   list_all_conv      now named list_all_iff
  2610   set_mem_eq         now named mem_iff
  2611 
  2612 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  2613 asymptotic "big O" calculations.  See the notes in BigO.thy.
  2614 
  2615 
  2616 *** HOL-Complex ***
  2617 
  2618 * Theory RealDef: better support for embedding natural numbers and
  2619 integers in the reals.
  2620 
  2621 The following theorems have been eliminated or modified
  2622 (INCOMPATIBILITY):
  2623 
  2624   exp_ge_add_one_self  now requires no hypotheses
  2625   real_of_int_add      reversed direction of equality (use [symmetric])
  2626   real_of_int_minus    reversed direction of equality (use [symmetric])
  2627   real_of_int_diff     reversed direction of equality (use [symmetric])
  2628   real_of_int_mult     reversed direction of equality (use [symmetric])
  2629 
  2630 * Theory RComplete: expanded support for floor and ceiling functions.
  2631 
  2632 * Theory Ln is new, with properties of the natural logarithm
  2633 
  2634 * Hyperreal: There is a new type constructor "star" for making
  2635 nonstandard types.  The old type names are now type synonyms:
  2636 
  2637   hypreal = real star
  2638   hypnat = nat star
  2639   hcomplex = complex star
  2640 
  2641 * Hyperreal: Many groups of similarly-defined constants have been
  2642 replaced by polymorphic versions (INCOMPATIBILITY):
  2643 
  2644   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2645 
  2646   starset      <-- starsetNat, starsetC
  2647   *s*          <-- *sNat*, *sc*
  2648   starset_n    <-- starsetNat_n, starsetC_n
  2649   *sn*         <-- *sNatn*, *scn*
  2650   InternalSets <-- InternalNatSets, InternalCSets
  2651 
  2652   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2653   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2654   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2655   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2656   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2657 
  2658 * Hyperreal: Many type-specific theorems have been removed in favor of
  2659 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2660 
  2661   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2662   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2663   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2664   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2665   right_minus <-- hypreal_add_minus
  2666   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2667   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2668   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2669   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2670   mult_1_right <-- hcomplex_mult_one_right
  2671   mult_zero_left <-- hcomplex_mult_zero_left
  2672   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2673   right_distrib <-- hypnat_add_mult_distrib2
  2674   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2675   right_inverse <-- hypreal_mult_inverse
  2676   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2677   order_refl <-- {hypreal,hypnat}_le_refl
  2678   order_trans <-- {hypreal,hypnat}_le_trans
  2679   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2680   order_less_le <-- {hypreal,hypnat}_less_le
  2681   linorder_linear <-- {hypreal,hypnat}_le_linear
  2682   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2683   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2684   add_nonneg_nonneg <-- hypreal_le_add_order
  2685 
  2686 * Hyperreal: Separate theorems having to do with type-specific
  2687 versions of constants have been merged into theorems that apply to the
  2688 new polymorphic constants (INCOMPATIBILITY):
  2689 
  2690   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2691   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2692   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2693   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2694   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2695   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2696   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2697   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2698   STAR_diff <-- {STAR,STARC}_diff
  2699   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2700     STARC_hcomplex_of_complex}_image_subset
  2701   starset_n_Un <-- starset{Nat,C}_n_Un
  2702   starset_n_Int <-- starset{Nat,C}_n_Int
  2703   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2704   starset_n_diff <-- starset{Nat,C}_n_diff
  2705   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2706   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2707   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2708   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2709   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2710   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2711   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2712   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2713   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2714   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2715   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2716   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2717   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2718   starfun_diff <-- starfun{C,RC,CR}_diff
  2719   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2720   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2721   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2722   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2723   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2724   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2725   starfun_Id <-- starfunC_Id
  2726   starfun_approx <-- starfun{Nat,CR}_approx
  2727   starfun_capprox <-- starfun{C,RC}_capprox
  2728   starfun_abs <-- starfunNat_rabs
  2729   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2730   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2731   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2732   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2733   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2734   starfun_add_approx <-- starfunCR_add_approx
  2735   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2736   starfun_divide <-- starfun{C,CR,RC}_divide
  2737   starfun_n <-- starfun{Nat,C}_n
  2738   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2739   starfun_n_add <-- starfun{Nat,C}_n_add
  2740   starfun_n_add_minus <-- starfunNat_n_add_minus
  2741   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2742   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2743   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2744 
  2745   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2746   star_n_minus <-- {hypreal,hcomplex}_minus
  2747   star_n_diff <-- {hypreal,hcomplex}_diff
  2748   star_n_mult <-- {hypreal,hcomplex}_mult
  2749   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2750   star_n_le <-- {hypreal,hypnat}_le
  2751   star_n_less <-- {hypreal,hypnat}_less
  2752   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2753   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2754   star_n_abs <-- hypreal_hrabs
  2755   star_n_divide <-- hcomplex_divide
  2756 
  2757   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2758   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2759   star_of_diff <-- hypreal_of_real_diff
  2760   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2761   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2762   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2763   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2764   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2765   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2766   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2767   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2768   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2769   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2770   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2771   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2772   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2773   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2774   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2775   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2776   star_of_power <-- hypreal_of_real_power
  2777   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2778 
  2779 * Hyperreal: new method "transfer" that implements the transfer
  2780 principle of nonstandard analysis. With a subgoal that mentions
  2781 nonstandard types like "'a star", the command "apply transfer"
  2782 replaces it with an equivalent one that mentions only standard types.
  2783 To be successful, all free variables must have standard types; non-
  2784 standard variables must have explicit universal quantifiers.
  2785 
  2786 * Hyperreal: A theory of Taylor series.
  2787 
  2788 
  2789 *** HOLCF ***
  2790 
  2791 * Discontinued special version of 'constdefs' (which used to support
  2792 continuous functions) in favor of the general Pure one with full
  2793 type-inference.
  2794 
  2795 * New simplification procedure for solving continuity conditions; it
  2796 is much faster on terms with many nested lambda abstractions (cubic
  2797 instead of exponential time).
  2798 
  2799 * New syntax for domain package: selector names are now optional.
  2800 Parentheses should be omitted unless argument is lazy, for example:
  2801 
  2802   domain 'a stream = cons "'a" (lazy "'a stream")
  2803 
  2804 * New command 'fixrec' for defining recursive functions with pattern
  2805 matching; defining multiple functions with mutual recursion is also
  2806 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2807 sinr, or any data constructor defined by the domain package. The given
  2808 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2809 syntax and examples.
  2810 
  2811 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2812 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2813 but the proof obligation additionally includes an admissibility
  2814 requirement. The packages generate instances of class cpo or pcpo,
  2815 with continuity and strictness theorems for Rep and Abs.
  2816 
  2817 * HOLCF: Many theorems have been renamed according to a more standard naming
  2818 scheme (INCOMPATIBILITY):
  2819 
  2820   foo_inject:  "foo$x = foo$y ==> x = y"
  2821   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2822   foo_less:    "(foo$x << foo$y) = (x << y)"
  2823   foo_strict:  "foo$UU = UU"
  2824   foo_defined: "... ==> foo$x ~= UU"
  2825   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2826 
  2827 
  2828 *** ZF ***
  2829 
  2830 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2831 including the First Isomorphism Theorem (on quotienting by the kernel
  2832 of a homomorphism).
  2833 
  2834 * ZF/Simplifier: install second copy of type solver that actually
  2835 makes use of TC rules declared to Isar proof contexts (or locales);
  2836 the old version is still required for ML proof scripts.
  2837 
  2838 
  2839 *** Cube ***
  2840 
  2841 * Converted to Isar theory format; use locales instead of axiomatic
  2842 theories.
  2843 
  2844 
  2845 *** ML ***
  2846 
  2847 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2848 for ||>, ||>>, |>>,
  2849 
  2850 * Pure/library.ML no longer defines its own option datatype, but uses
  2851 that of the SML basis, which has constructors NONE and SOME instead of
  2852 None and Some, as well as exception Option.Option instead of OPTION.
  2853 The functions the, if_none, is_some, is_none have been adapted
  2854 accordingly, while Option.map replaces apsome.
  2855 
  2856 * Pure/library.ML: the exception LIST has been given up in favour of
  2857 the standard exceptions Empty and Subscript, as well as
  2858 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2859 superceded by the standard hd and tl functions etc.
  2860 
  2861 A number of basic list functions are no longer exported to the ML
  2862 toplevel, as they are variants of predefined functions.  The following
  2863 suggests how one can translate existing code:
  2864 
  2865     rev_append xs ys = List.revAppend (xs, ys)
  2866     nth_elem (i, xs) = List.nth (xs, i)
  2867     last_elem xs = List.last xs
  2868     flat xss = List.concat xss
  2869     seq fs = List.app fs
  2870     partition P xs = List.partition P xs
  2871     mapfilter f xs = List.mapPartial f xs
  2872 
  2873 * Pure/library.ML: several combinators for linear functional
  2874 transformations, notably reverse application and composition:
  2875 
  2876   x |> f                f #> g
  2877   (x, y) |-> f          f #-> g
  2878 
  2879 * Pure/library.ML: introduced/changed precedence of infix operators:
  2880 
  2881   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2882   infix 2 ?;
  2883   infix 3 o oo ooo oooo;
  2884   infix 4 ~~ upto downto;
  2885 
  2886 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2887 infix operators.
  2888 
  2889 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2890 fold_map support linear functional transformations and nesting.  For
  2891 example:
  2892 
  2893   fold f [x1, ..., xN] y =
  2894     y |> f x1 |> ... |> f xN
  2895 
  2896   (fold o fold) f [xs1, ..., xsN] y =
  2897     y |> fold f xs1 |> ... |> fold f xsN
  2898 
  2899   fold f [x1, ..., xN] =
  2900     f x1 #> ... #> f xN
  2901 
  2902   (fold o fold) f [xs1, ..., xsN] =
  2903     fold f xs1 #> ... #> fold f xsN
  2904 
  2905 * Pure/library.ML: the following selectors on type 'a option are
  2906 available:
  2907 
  2908   the:               'a option -> 'a  (*partial*)
  2909   these:             'a option -> 'a  where 'a = 'b list
  2910   the_default: 'a -> 'a option -> 'a
  2911   the_list:          'a option -> 'a list
  2912 
  2913 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2914 basic operations for association lists, following natural argument
  2915 order; moreover the explicit equality predicate passed here avoids
  2916 potentially expensive polymorphic runtime equality checks.
  2917 The old functions may be expressed as follows:
  2918 
  2919   assoc = uncurry (AList.lookup (op =))
  2920   assocs = these oo AList.lookup (op =)
  2921   overwrite = uncurry (AList.update (op =)) o swap
  2922 
  2923 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2924 
  2925   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2926   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2927 
  2928 replacing make_keylist and keyfilter (occassionally used)
  2929 Naive rewrites:
  2930 
  2931   make_keylist = AList.make
  2932   keyfilter = AList.find (op =)
  2933 
  2934 * eq_fst and eq_snd now take explicit equality parameter, thus
  2935   avoiding eqtypes. Naive rewrites:
  2936 
  2937     eq_fst = eq_fst (op =)
  2938     eq_snd = eq_snd (op =)
  2939 
  2940 * Removed deprecated apl and apr (rarely used).
  2941   Naive rewrites:
  2942 
  2943     apl (n, op) =>>= curry op n
  2944     apr (op, m) =>>= fn n => op (n, m)
  2945 
  2946 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2947 provides a reasonably efficient light-weight implementation of sets as
  2948 lists.
  2949 
  2950 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2951 few new operations; existing lookup and update are now curried to
  2952 follow natural argument order (for use with fold etc.);
  2953 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2954 
  2955 * Pure/General: output via the Isabelle channels of
  2956 writeln/warning/error etc. is now passed through Output.output, with a
  2957 hook for arbitrary transformations depending on the print_mode
  2958 (cf. Output.add_mode -- the first active mode that provides a output
  2959 function wins).  Already formatted output may be embedded into further
  2960 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2961 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2962 accommodate easy composition of diagnostic messages etc.  Programmers
  2963 rarely need to care about Output.output or Output.raw at all, with
  2964 some notable exceptions: Output.output is required when bypassing the
  2965 standard channels (writeln etc.), or in token translations to produce
  2966 properly formatted results; Output.raw is required when capturing
  2967 already output material that will eventually be presented to the user
  2968 a second time.  For the default print mode, both Output.output and
  2969 Output.raw have no effect.
  2970 
  2971 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2972 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2973 cumulative results are displayed at the end of a batch session.
  2974 
  2975 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2976 replaced by File.platform_path and File.shell_path (with appropriate
  2977 hooks).  This provides a clean interface for unusual systems where the
  2978 internal and external process view of file names are different.
  2979 
  2980 * Pure: more efficient orders for basic syntactic entities: added
  2981 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2982 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2983 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2984 orders now -- potential INCOMPATIBILITY for code that depends on a
  2985 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2986 Library.sort_strings on result).
  2987 
  2988 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2989 fold_types traverse types/terms from left to right, observing natural
  2990 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2991 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2992 
  2993 * Pure: name spaces have been refined, with significant changes of the
  2994 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2995 to extern(_table).  The plain name entry path is superceded by a
  2996 general 'naming' context, which also includes the 'policy' to produce
  2997 a fully qualified name and external accesses of a fully qualified
  2998 name; NameSpace.extend is superceded by context dependent
  2999 Sign.declare_name.  Several theory and proof context operations modify
  3000 the naming context.  Especially note Theory.restore_naming and
  3001 ProofContext.restore_naming to get back to a sane state; note that
  3002 Theory.add_path is no longer sufficient to recover from
  3003 Theory.absolute_path in particular.
  3004 
  3005 * Pure: new flags short_names (default false) and unique_names
  3006 (default true) for controlling output of qualified names.  If
  3007 short_names is set, names are printed unqualified.  If unique_names is
  3008 reset, the name prefix is reduced to the minimum required to achieve
  3009 the original result when interning again, even if there is an overlap
  3010 with earlier declarations.
  3011 
  3012 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3013 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3014 (useful for printing error messages).  INCOMPATIBILITY.
  3015 
  3016 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3017 Theory.theory are now identified, referring to the universal
  3018 Context.theory (see Pure/context.ML).  Actual signature and theory
  3019 content is managed as theory data.  The old code and interfaces were
  3020 spread over many files and structures; the new arrangement introduces
  3021 considerable INCOMPATIBILITY to gain more clarity:
  3022 
  3023   Context -- theory management operations (name, identity, inclusion,
  3024     parents, ancestors, merge, etc.), plus generic theory data;
  3025 
  3026   Sign -- logical signature and syntax operations (declaring consts,
  3027     types, etc.), plus certify/read for common entities;
  3028 
  3029   Theory -- logical theory operations (stating axioms, definitions,
  3030     oracles), plus a copy of logical signature operations (consts,
  3031     types, etc.); also a few basic management operations (Theory.copy,
  3032     Theory.merge, etc.)
  3033 
  3034 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3035 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3036 for convenience -- they merely return the theory.
  3037 
  3038 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3039 
  3040 * Pure: the Isar proof context type is already defined early in Pure
  3041 as Context.proof (note that ProofContext.context and Proof.context are
  3042 aliases, where the latter is the preferred name).  This enables other
  3043 Isabelle components to refer to that type even before Isar is present.
  3044 
  3045 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3046 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3047 any of these kinds.  For example, Sign.intern typeK is now
  3048 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3049 Theory.hide_types.  Also note that former
  3050 Theory.hide_classes/types/consts are now
  3051 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3052 internalize their arguments!  INCOMPATIBILITY.
  3053 
  3054 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3055 datatype thmref (with constructors Name and NameSelection) instead of
  3056 plain string -- INCOMPATIBILITY;
  3057 
  3058 * Pure: cases produced by proof methods specify options, where NONE
  3059 means to remove case bindings -- INCOMPATIBILITY in
  3060 (RAW_)METHOD_CASES.
  3061 
  3062 * Pure: the following operations retrieve axioms or theorems from a
  3063 theory node or theory hierarchy, respectively:
  3064 
  3065   Theory.axioms_of: theory -> (string * term) list
  3066   Theory.all_axioms_of: theory -> (string * term) list
  3067   PureThy.thms_of: theory -> (string * thm) list
  3068   PureThy.all_thms_of: theory -> (string * thm) list
  3069 
  3070 * Pure: print_tac now outputs the goal through the trace channel.
  3071 
  3072 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3073 Reference Toplevel.debug (default false) controls detailed printing
  3074 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3075 controls execution profiling -- set to 1 for time and 2 for space
  3076 (both increase the runtime).
  3077 
  3078 * Isar session: The initial use of ROOT.ML is now always timed,
  3079 i.e. the log will show the actual process times, in contrast to the
  3080 elapsed wall-clock time that the outer shell wrapper produces.
  3081 
  3082 * Simplifier: improved handling of bound variables (nameless
  3083 representation, avoid allocating new strings).  Simprocs that invoke
  3084 the Simplifier recursively should use Simplifier.inherit_bounds to
  3085 avoid local name clashes.  Failure to do so produces warnings
  3086 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3087 for further details.
  3088 
  3089 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3090 bindings for all theorems stored within a given theory; this may help
  3091 in porting non-Isar theories to Isar ones, while keeping ML proof
  3092 scripts for the time being.
  3093 
  3094 * ML operator HTML.with_charset specifies the charset begin used for
  3095 generated HTML files.  For example:
  3096 
  3097   HTML.with_charset "utf-8" use_thy "Hebrew";
  3098   HTML.with_charset "utf-8" use_thy "Chinese";
  3099 
  3100 
  3101 *** System ***
  3102 
  3103 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3104 isabelle, isatool etc.).
  3105 
  3106 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3107 isatool doc, isatool mkdir, display_drafts etc.).
  3108 
  3109 * isatool usedir: option -f allows specification of the ML file to be
  3110 used by Isabelle; default is ROOT.ML.
  3111 
  3112 * New isatool version outputs the version identifier of the Isabelle
  3113 distribution being used.
  3114 
  3115 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3116 (containing Boolean satisfiability problems) into Isabelle/HOL
  3117 theories.
  3118 
  3119 
  3120 
  3121 New in Isabelle2004 (April 2004)
  3122 --------------------------------
  3123 
  3124 *** General ***
  3125 
  3126 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3127   Replaces linorder.ML.
  3128 
  3129 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3130   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3131   (\<a>...\<z>), are now considered normal letters, and can therefore
  3132   be used anywhere where an ASCII letter (a...zA...Z) has until
  3133   now. COMPATIBILITY: This obviously changes the parsing of some
  3134   terms, especially where a symbol has been used as a binder, say
  3135   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3136   as an identifier.  Fix it by inserting a space around former
  3137   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3138   existing theory and ML files.
  3139 
  3140 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3141 
  3142 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3143   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3144   a normal (but invisible) letter. For multiple letter subscripts repeat
  3145   \<^isub> like this: x\<^isub>1\<^isub>2.
  3146 
  3147 * Pure: There are now sub-/superscripts that can span more than one
  3148   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3149   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3150   superscript. The new control characters are not identifier parts.
  3151 
  3152 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3153   content of "..." to the latex file instead of \isacntrl... . The "..."
  3154   may consist of any printable characters excluding the end bracket >.
  3155 
  3156 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3157   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3158   declare constants "final", which prevents their being given a definition
  3159   later.  It is useful for constants whose behaviour is fixed axiomatically
  3160   rather than definitionally, such as the meta-logic connectives.
  3161 
  3162 * Pure: 'instance' now handles general arities with general sorts
  3163   (i.e. intersections of classes),
  3164 
  3165 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3166   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3167   It can be changed to alter the colors/layout of generated pages.
  3168 
  3169 
  3170 *** Isar ***
  3171 
  3172 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3173   cut_tac, subgoal_tac and thin_tac:
  3174   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3175     locales are no longer forced to write Isar proof scripts.
  3176     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3177     emulations.
  3178   - INCOMPATIBILITY: names of variables to be instantiated may no
  3179     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3180     This is consistent with the instantiation attribute "where".
  3181 
  3182 * Attributes "where" and "of":
  3183   - Now take type variables of instantiated theorem into account when reading
  3184     the instantiation string.  This fixes a bug that caused instantiated
  3185     theorems to have too special types in some circumstances.
  3186   - "where" permits explicit instantiations of type variables.
  3187 
  3188 * Calculation commands "moreover" and "also" no longer interfere with
  3189   current facts ("this"), admitting arbitrary combinations with "then"
  3190   and derived forms.
  3191 
  3192 * Locales:
  3193   - Goal statements involving the context element "includes" no longer
  3194     generate theorems with internal delta predicates (those ending on
  3195     "_axioms") in the premise.
  3196     Resolve particular premise with <locale>.intro to obtain old form.
  3197   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3198     specification and "includes" elements in goal statement.
  3199   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3200     [intro?] and [elim?] (respectively) by default.
  3201   - Experimental command for instantiation of locales in proof contexts:
  3202         instantiate <label>[<attrs>]: <loc>
  3203     Instantiates locale <loc> and adds all its theorems to the current context
  3204     taking into account their attributes.  Label and attrs are optional
  3205     modifiers, like in theorem declarations.  If present, names of
  3206     instantiated theorems are qualified with <label>, and the attributes
  3207     <attrs> are applied after any attributes these theorems might have already.
  3208       If the locale has assumptions, a chained fact of the form
  3209     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3210     are derived.  The command does not support old-style locales declared
  3211     with "locale (open)".
  3212       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3213 
  3214 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3215   (Isar) contexts.
  3216 
  3217 
  3218 *** HOL ***
  3219 
  3220 * Proof import: new image HOL4 contains the imported library from
  3221   the HOL4 system with about 2500 theorems. It is imported by
  3222   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3223   can be used like any other Isabelle image.  See
  3224   HOL/Import/HOL/README for more information.
  3225 
  3226 * Simplifier:
  3227   - Much improved handling of linear and partial orders.
  3228     Reasoners for linear and partial orders are set up for type classes
  3229     "linorder" and "order" respectively, and are added to the default simpset
  3230     as solvers.  This means that the simplifier can build transitivity chains
  3231     to solve goals from the assumptions.
  3232   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3233     of blast or auto after simplification become unnecessary because the goal
  3234     is solved by simplification already.
  3235 
  3236 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3237     all proved in axiomatic type classes for semirings, rings and fields.
  3238 
  3239 * Numerics:
  3240   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3241     now formalized using the Ring_and_Field theory mentioned above.
  3242   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3243     than before, because now they are set up once in a generic manner.
  3244   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3245     Look for the general versions in Ring_and_Field (and Power if they concern
  3246     exponentiation).
  3247 
  3248 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3249 
  3250 * Records:
  3251   - Record types are now by default printed with their type abbreviation
  3252     instead of the list of all field types. This can be configured via
  3253     the reference "print_record_type_abbr".
  3254   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3255     (not enabled by default).
  3256   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3257     EX x. x = sel r to True (not enabled by default).
  3258   - Tactic "record_split_simp_tac" to split and simplify records added.
  3259 
  3260 * 'specification' command added, allowing for definition by
  3261   specification.  There is also an 'ax_specification' command that
  3262   introduces the new constants axiomatically.
  3263 
  3264 * arith(_tac) is now able to generate counterexamples for reals as well.
  3265 
  3266 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3267 
  3268 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3269   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3270 
  3271 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3272   matrix theory to linear programming.
  3273 
  3274 * Unions and Intersections:
  3275   The latex output syntax of UN and INT has been changed
  3276   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3277   i.e. the index formulae has become a subscript.
  3278   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3279 
  3280 * Unions and Intersections over Intervals:
  3281   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3282   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3283   like in normal math, and corresponding versions for < and for intersection.
  3284 
  3285 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3286   lexicographic dictonary ordering has been added as "lexord".
  3287 
  3288 * ML: the legacy theory structures Int and List have been removed. They had
  3289   conflicted with ML Basis Library structures having the same names.
  3290 
  3291 * 'refute' command added to search for (finite) countermodels.  Only works
  3292   for a fragment of HOL.  The installation of an external SAT solver is
  3293   highly recommended.  See "HOL/Refute.thy" for details.
  3294 
  3295 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3296   formulae under an assignment of free variables to random values.
  3297   In contrast to 'refute', it can deal with inductive datatypes,
  3298   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3299   for examples.
  3300 
  3301 
  3302 *** HOLCF ***
  3303 
  3304 * Streams now come with concatenation and are part of the HOLCF image
  3305 
  3306 
  3307 
  3308 New in Isabelle2003 (May 2003)
  3309 ------------------------------
  3310 
  3311 *** General ***
  3312 
  3313 * Provers/simplifier:
  3314 
  3315   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3316     Assumptions are now subject to complete mutual simplification,
  3317     not just from left to right. The simplifier now preserves
  3318     the order of assumptions.
  3319 
  3320     Potential INCOMPATIBILITY:
  3321 
  3322     -- simp sometimes diverges where the old version did
  3323        not, e.g. invoking simp on the goal
  3324 
  3325         [| P (f x); y = x; f x = f y |] ==> Q
  3326 
  3327        now gives rise to the infinite reduction sequence
  3328 
  3329         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3330 
  3331        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3332        kind of problem.
  3333 
  3334     -- Tactics combining classical reasoner and simplification (such as auto)
  3335        are also affected by this change, because many of them rely on
  3336        simp. They may sometimes diverge as well or yield a different numbers
  3337        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3338        in case of problems. Sometimes subsequent calls to the classical
  3339        reasoner will fail because a preceeding call to the simplifier too
  3340        eagerly simplified the goal, e.g. deleted redundant premises.
  3341 
  3342   - The simplifier trace now shows the names of the applied rewrite rules
  3343 
  3344   - You can limit the number of recursive invocations of the simplifier
  3345     during conditional rewriting (where the simplifie tries to solve the
  3346     conditions before applying the rewrite rule):
  3347     ML "simp_depth_limit := n"
  3348     where n is an integer. Thus you can force termination where previously
  3349     the simplifier would diverge.
  3350 
  3351   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3352 
  3353   - No longer aborts on failed congruence proof.  Instead, the
  3354     congruence is ignored.
  3355 
  3356 * Pure: New generic framework for extracting programs from constructive
  3357   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3358   as HOL/Extraction for some case studies.
  3359 
  3360 * Pure: The main goal of the proof state is no longer shown by default, only
  3361 the subgoals. This behaviour is controlled by a new flag.
  3362    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3363 (ML: Proof.show_main_goal).
  3364 
  3365 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3366 rules whose conclusion matches subgoal 1:
  3367       PG menu: Isabelle/Isar -> Show me -> matching rules
  3368 The rules are ordered by how closely they match the subgoal.
  3369 In particular, rules that solve a subgoal outright are displayed first
  3370 (or rather last, the way they are printed).
  3371 (ML: ProofGeneral.print_intros())
  3372 
  3373 * Pure: New flag trace_unify_fail causes unification to print
  3374 diagnostic information (PG: in trace buffer) when it fails. This is
  3375 useful for figuring out why single step proofs like rule, erule or
  3376 assumption failed.
  3377 
  3378 * Pure: Locale specifications now produce predicate definitions
  3379 according to the body of text (covering assumptions modulo local
  3380 definitions); predicate "loc_axioms" covers newly introduced text,
  3381 while "loc" is cumulative wrt. all included locale expressions; the
  3382 latter view is presented only on export into the global theory
  3383 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3384 on the old view without predicates;
  3385 
  3386 * Pure: predefined locales "var" and "struct" are useful for sharing
  3387 parameters (as in CASL, for example); just specify something like
  3388 ``var x + var y + struct M'' as import;
  3389 
  3390 * Pure: improved thms_containing: proper indexing of facts instead of
  3391 raw theorems; check validity of results wrt. current name space;
  3392 include local facts of proof configuration (also covers active
  3393 locales), cover fixed variables in index; may use "_" in term
  3394 specification; an optional limit for the number of printed facts may
  3395 be given (the default is 40);
  3396 
  3397 * Pure: disallow duplicate fact bindings within new-style theory files
  3398 (batch-mode only);
  3399 
  3400 * Provers: improved induct method: assumptions introduced by case
  3401 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3402 the goal statement); "foo" still refers to all facts collectively;
  3403 
  3404 * Provers: the function blast.overloaded has been removed: all constants
  3405 are regarded as potentially overloaded, which improves robustness in exchange
  3406 for slight decrease in efficiency;
  3407 
  3408 * Provers/linorder: New generic prover for transitivity reasoning over
  3409 linear orders.  Note: this prover is not efficient!
  3410 
  3411 * Isar: preview of problems to finish 'show' now produce an error
  3412 rather than just a warning (in interactive mode);
  3413 
  3414 
  3415 *** HOL ***
  3416 
  3417 * arith(_tac)
  3418 
  3419  - Produces a counter example if it cannot prove a goal.
  3420    Note that the counter example may be spurious if the goal is not a formula
  3421    of quantifier-free linear arithmetic.
  3422    In ProofGeneral the counter example appears in the trace buffer.
  3423 
  3424  - Knows about div k and mod k where k is a numeral of type nat or int.
  3425 
  3426  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3427    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3428    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3429 
  3430 * simp's arithmetic capabilities have been enhanced a bit: it now
  3431 takes ~= in premises into account (by performing a case split);
  3432 
  3433 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3434 are distributed over a sum of terms;
  3435 
  3436 * New tactic "trans_tac" and method "trans" instantiate
  3437 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3438 "<=", "<" and "=").
  3439 
  3440 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3441 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3442 
  3443 * 'typedef' command has new option "open" to suppress the set
  3444 definition;
  3445 
  3446 * functions Min and Max on finite sets have been introduced (theory
  3447 Finite_Set);
  3448 
  3449 * attribute [symmetric] now works for relations as well; it turns
  3450 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3451 
  3452 * induct over a !!-quantified statement (say !!x1..xn):
  3453   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3454 
  3455 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3456 %x. None. Warning: empty_def now refers to the previously hidden definition
  3457 of the empty set.
  3458 
  3459 * Algebra: formalization of classical algebra.  Intended as base for
  3460 any algebraic development in Isabelle.  Currently covers group theory
  3461 (up to Sylow's theorem) and ring theory (Universal Property of
  3462 Univariate Polynomials).  Contributions welcome;
  3463 
  3464 * GroupTheory: deleted, since its material has been moved to Algebra;
  3465 
  3466 * Complex: new directory of the complex numbers with numeric constants,
  3467 nonstandard complex numbers, and some complex analysis, standard and
  3468 nonstandard (Jacques Fleuriot);
  3469 
  3470 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3471 
  3472 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3473 Fleuriot);
  3474 
  3475 * Real/HahnBanach: updated and adapted to locales;
  3476 
  3477 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3478 Gray and Kramer);
  3479 
  3480 * UNITY: added the Meier-Sanders theory of progress sets;
  3481 
  3482 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3483 as abstract algorithms, instantiated to the JVM;
  3484 
  3485 * Bali: Java source language formalization. Type system, operational
  3486 semantics, axiomatic semantics. Supported language features:
  3487 classes, interfaces, objects,virtual methods, static methods,
  3488 static/instance fields, arrays, access modifiers, definite
  3489 assignment, exceptions.
  3490 
  3491 
  3492 *** ZF ***
  3493 
  3494 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3495 universe, etc.);
  3496 
  3497 * Main ZF: virtually all theories converted to new-style format;
  3498 
  3499 
  3500 *** ML ***
  3501 
  3502 * Pure: Tactic.prove provides sane interface for internal proofs;
  3503 omits the infamous "standard" operation, so this is more appropriate
  3504 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3505 
  3506 * Pure: improved error reporting of simprocs;
  3507 
  3508 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3509 up simprocs;
  3510 
  3511 
  3512 *** Document preparation ***
  3513 
  3514 * uses \par instead of \\ for line breaks in theory text. This may
  3515 shift some page breaks in large documents. To get the old behaviour
  3516 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3517 
  3518 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3519 other packages
  3520 
  3521 * \<euro> now needs package babel/greek instead of marvosym (which
  3522 broke \Rightarrow)
  3523 
  3524 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3525 textcomp package)
  3526 
  3527 
  3528 
  3529 New in Isabelle2002 (March 2002)
  3530 --------------------------------
  3531 
  3532 *** Document preparation ***
  3533 
  3534 * greatly simplified document preparation setup, including more
  3535 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3536 instructive isatool mkdir; users should basically be able to get
  3537 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3538 users may run a separate document processing stage manually like this:
  3539 "isatool usedir -D output HOL Test && isatool document Test/output";
  3540 
  3541 * theory dependency graph may now be incorporated into documents;
  3542 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3543 with \includegraphics of LaTeX;
  3544 
  3545 * proper spacing of consecutive markup elements, especially text
  3546 blocks after section headings;
  3547 
  3548 * support bold style (for single symbols only), input syntax is like
  3549 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3550 
  3551 * \<bullet> is now output as bold \cdot by default, which looks much
  3552 better in printed text;
  3553 
  3554 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3555 note that these symbols are currently unavailable in Proof General /
  3556 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3557 
  3558 * isatool latex no longer depends on changed TEXINPUTS, instead
  3559 isatool document copies the Isabelle style files to the target
  3560 location;
  3561 
  3562 
  3563 *** Isar ***
  3564 
  3565 * Pure/Provers: improved proof by cases and induction;
  3566   - 'case' command admits impromptu naming of parameters (such as
  3567     "case (Suc n)");
  3568   - 'induct' method divinates rule instantiation from the inductive
  3569     claim; no longer requires excessive ?P bindings for proper
  3570     instantiation of cases;
  3571   - 'induct' method properly enumerates all possibilities of set/type
  3572     rules; as a consequence facts may be also passed through *type*
  3573     rules without further ado;
  3574   - 'induct' method now derives symbolic cases from the *rulified*
  3575     rule (before it used to rulify cases stemming from the internal
  3576     atomized version); this means that the context of a non-atomic
  3577     statement becomes is included in the hypothesis, avoiding the
  3578     slightly cumbersome show "PROP ?case" form;
  3579   - 'induct' may now use elim-style induction rules without chaining
  3580     facts, using ``missing'' premises from the goal state; this allows
  3581     rules stemming from inductive sets to be applied in unstructured
  3582     scripts, while still benefitting from proper handling of non-atomic
  3583     statements; NB: major inductive premises need to be put first, all
  3584     the rest of the goal is passed through the induction;
  3585   - 'induct' proper support for mutual induction involving non-atomic
  3586     rule statements (uses the new concept of simultaneous goals, see
  3587     below);
  3588   - append all possible rule selections, but only use the first
  3589     success (no backtracking);
  3590   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3591   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3592   - added 'print_induct_rules' (covered by help item in recent Proof
  3593     General versions);
  3594   - moved induct/cases attributes to Pure, methods to Provers;
  3595   - generic method setup instantiated for FOL and HOL;
  3596 
  3597 * Pure: support multiple simultaneous goal statements, for example
  3598 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3599 meta-level mechanism, this acts as if several individual goals had
  3600 been stated separately; in particular common proof methods need to be
  3601 repeated in order to cover all claims; note that a single elimination
  3602 step is *not* sufficient to establish the two conjunctions, so this
  3603 fails:
  3604 
  3605   assume "A & B" then have A and B ..   (*".." fails*)
  3606 
  3607 better use "obtain" in situations as above; alternative refer to
  3608 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  3609 
  3610 * Pure: proper integration with ``locales''; unlike the original
  3611 version by Florian Kammller, Isar locales package high-level proof
  3612 contexts rather than raw logical ones (e.g. we admit to include
  3613 attributes everywhere); operations on locales include merge and
  3614 rename; support for implicit arguments (``structures''); simultaneous
  3615 type-inference over imports and text; see also HOL/ex/Locales.thy for
  3616 some examples;
  3617 
  3618 * Pure: the following commands have been ``localized'', supporting a
  3619 target locale specification "(in name)": 'lemma', 'theorem',
  3620 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  3621 stored both within the locale and at the theory level (exported and
  3622 qualified by the locale name);
  3623 
  3624 * Pure: theory goals may now be specified in ``long'' form, with
  3625 ad-hoc contexts consisting of arbitrary locale elements. for example
  3626 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  3627 definitions may be given, too); the result is a meta-level rule with
  3628 the context elements being discharged in the obvious way;
  3629 
  3630 * Pure: new proof command 'using' allows to augment currently used
  3631 facts after a goal statement ('using' is syntactically analogous to
  3632 'apply', but acts on the goal's facts only); this allows chained facts
  3633 to be separated into parts given before and after a claim, as in
  3634 ``from a and b have C using d and e <proof>'';
  3635 
  3636 * Pure: renamed "antecedent" case to "rule_context";
  3637 
  3638 * Pure: new 'judgment' command records explicit information about the
  3639 object-logic embedding (used by several tools internally); no longer
  3640 use hard-wired "Trueprop";
  3641 
  3642 * Pure: added 'corollary' command;
  3643 
  3644 * Pure: fixed 'token_translation' command;
  3645 
  3646 * Pure: removed obsolete 'exported' attribute;
  3647 
  3648 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3649 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3650 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3651 
  3652 * Pure: method 'atomize' presents local goal premises as object-level
  3653 statements (atomic meta-level propositions); setup controlled via
  3654 rewrite rules declarations of 'atomize' attribute; example
  3655 application: 'induct' method with proper rule statements in improper
  3656 proof *scripts*;
  3657 
  3658 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3659 now consider the syntactic context of assumptions, giving a better
  3660 chance to get type-inference of the arguments right (this is
  3661 especially important for locales);
  3662 
  3663 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3664 mode;
  3665 
  3666 * Pure/obtain: the formal conclusion "thesis", being marked as
  3667 ``internal'', may no longer be reference directly in the text;
  3668 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3669 situations;
  3670 
  3671 * Pure: generic 'sym' attribute which declares a rule both as pure
  3672 'elim?' and for the 'symmetric' operation;
  3673 
  3674 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3675 text; the fixed correlation with particular command syntax has been
  3676 discontinued;
  3677 
  3678 * Pure: new method 'rules' is particularly well-suited for proof
  3679 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3680 but often produces more compact proof terms with less detours;
  3681 
  3682 * Pure/Provers/classical: simplified integration with pure rule
  3683 attributes and methods; the classical "intro?/elim?/dest?"
  3684 declarations coincide with the pure ones; the "rule" method no longer
  3685 includes classically swapped intros; "intro" and "elim" methods no
  3686 longer pick rules from the context; also got rid of ML declarations
  3687 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3688 INCOMPATIBILITY;
  3689 
  3690 * Provers/classical: attribute 'swapped' produces classical inversions
  3691 of introduction rules;
  3692 
  3693 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3694 rules instead of full simplifier context; 'iff' attribute handles
  3695 conditional rules;
  3696 
  3697 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3698 
  3699 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3700 "(permissive)" option to recover old behavior;
  3701 
  3702 * HOL: 'inductive' no longer features separate (collective) attributes
  3703 for 'intros' (was found too confusing);
  3704 
  3705 * HOL: properly declared induction rules less_induct and
  3706 wf_induct_rule;
  3707 
  3708 
  3709 *** HOL ***
  3710 
  3711 * HOL: moved over to sane numeral syntax; the new policy is as
  3712 follows:
  3713 
  3714   - 0 and 1 are polymorphic constants, which are defined on any
  3715   numeric type (nat, int, real etc.);
  3716 
  3717   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3718   binary representation internally;
  3719 
  3720   - type nat has special constructor Suc, and generally prefers Suc 0
  3721   over 1::nat and Suc (Suc 0) over 2::nat;
  3722 
  3723 This change may cause significant problems of INCOMPATIBILITY; here
  3724 are some hints on converting existing sources:
  3725 
  3726   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3727   entities, so expressions involving "-" (unary or binary minus) need
  3728   to be spaced properly;
  3729 
  3730   - existing occurrences of "1" may need to be constraint "1::nat" or
  3731   even replaced by Suc 0; similar for old "2";
  3732 
  3733   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3734 
  3735   - remove all special provisions on numerals in proofs;
  3736 
  3737 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3738 representation (depends on bin_arith_simps in the default context);
  3739 
  3740 * HOL: symbolic syntax for x^2 (numeral 2);
  3741 
  3742 * HOL: the class of all HOL types is now called "type" rather than
  3743 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3744 in axclass/classes, instance/arities, and (usually rare) occurrences
  3745 in typings (of consts etc.); internally the class is called
  3746 "HOL.type", ML programs should refer to HOLogic.typeS;
  3747 
  3748 * HOL/record package improvements:
  3749   - new derived operations "fields" to build a partial record section,
  3750     "extend" to promote a fixed record to a record scheme, and
  3751     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3752     declared as simp by default;
  3753   - shared operations ("more", "fields", etc.) now need to be always
  3754     qualified) --- potential INCOMPATIBILITY;
  3755   - removed "make_scheme" operations (use "make" with "extend") --
  3756     INCOMPATIBILITY;
  3757   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3758   - provides cases/induct rules for use with corresponding Isar
  3759     methods (for concrete records, record schemes, concrete more
  3760     parts, and schematic more parts -- in that order);
  3761   - internal definitions directly based on a light-weight abstract
  3762     theory of product types over typedef rather than datatype;
  3763 
  3764 * HOL: generic code generator for generating executable ML code from
  3765 specifications; specific support for HOL constructs such as inductive
  3766 datatypes and sets, as well as recursive functions; can be invoked
  3767 via 'generate_code' theory section;
  3768 
  3769 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3770 
  3771 * HOL: consolidated and renamed several theories.  In particular:
  3772         Ord.thy has been absorbed into HOL.thy
  3773         String.thy has been absorbed into List.thy
  3774 
  3775 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3776 (beware of argument permutation!);
  3777 
  3778 * HOL: linorder_less_split superseded by linorder_cases;
  3779 
  3780 * HOL/List: "nodups" renamed to "distinct";
  3781 
  3782 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3783 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3784   - Ex_def has changed, now need to use some_eq_ex
  3785 
  3786 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3787 in this (rare) case use:
  3788 
  3789   delSWrapper "split_all_tac"
  3790   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3791 
  3792 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3793 MAY FAIL;
  3794 
  3795 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3796 Isabelle's type classes, ^ on functions and relations has too general
  3797 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3798 necessary to attach explicit type constraints;
  3799 
  3800 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3801 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3802 renamed accordingly (eg "compI" -> "rel_compI").
  3803 
  3804 * HOL: syntax translations now work properly with numerals and records
  3805 expressions;
  3806 
  3807 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3808 of "lam" -- INCOMPATIBILITY;
  3809 
  3810 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3811 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3812 renamed "Product_Type.unit";
  3813 
  3814 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3815 
  3816 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3817 the "cases" method);
  3818 
  3819 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3820 Florian Kammller);
  3821 
  3822 * HOL/IMP: updated and converted to new-style theory format; several
  3823 parts turned into readable document, with proper Isar proof texts and
  3824 some explanations (by Gerwin Klein);
  3825 
  3826 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3827 
  3828 * HOL-Hyperreal is now a logic image;
  3829 
  3830 
  3831 *** HOLCF ***
  3832 
  3833 * Isar: consts/constdefs supports mixfix syntax for continuous
  3834 operations;
  3835 
  3836 * Isar: domain package adapted to new-style theory format, e.g. see
  3837 HOLCF/ex/Dnat.thy;
  3838 
  3839 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3840 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3841 lift.induct_tac, always use UU instead of Undef;
  3842 
  3843 * HOLCF/IMP: updated and converted to new-style theory;
  3844 
  3845 
  3846 *** ZF ***
  3847 
  3848 * Isar: proper integration of logic-specific tools and packages,
  3849 including theory commands '(co)inductive', '(co)datatype',
  3850 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3851 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3852 
  3853 * theory Main no longer includes AC; for the Axiom of Choice, base
  3854 your theory on Main_ZFC;
  3855 
  3856 * the integer library now covers quotients and remainders, with many
  3857 laws relating division to addition, multiplication, etc.;
  3858 
  3859 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3860 typeless version of the formalism;
  3861 
  3862 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3863 format;
  3864 
  3865 * ZF/Induct: new directory for examples of inductive definitions,
  3866 including theory Multiset for multiset orderings; converted to
  3867 new-style theory format;
  3868 
  3869 * ZF: many new theorems about lists, ordinals, etc.;
  3870 
  3871 
  3872 *** General ***
  3873 
  3874 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3875 variable proof controls level of detail: 0 = no proofs (only oracle
  3876 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3877 also ref manual for further ML interfaces;
  3878 
  3879 * Pure/axclass: removed obsolete ML interface
  3880 goal_subclass/goal_arity;
  3881 
  3882 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3883 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3884 separate tokens, so expressions involving minus need to be spaced
  3885 properly;
  3886 
  3887 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3888 rather than "infixl" or "infixr";
  3889 
  3890 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3891 sort constraint specifications in type inference; e.g. "x::_::foo"
  3892 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3893 type variable);
  3894 
  3895 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3896 control output of nested => (types); the default behavior is
  3897 "type_brackets";
  3898 
  3899 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3900 tokens into AST constants;
  3901 
  3902 * Pure/syntax: prefer later declarations of translations and print
  3903 translation functions; potential INCOMPATIBILITY: need to reverse
  3904 multiple declarations for same syntax element constant;
  3905 
  3906 * Pure/show_hyps reset by default (in accordance to existing Isar
  3907 practice);
  3908 
  3909 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3910 addSafter;
  3911 
  3912 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3913 as well;
  3914 
  3915 * system: tested support for MacOS X; should be able to get Isabelle +
  3916 Proof General to work in a plain Terminal after installing Poly/ML
  3917 (e.g. from the Isabelle distribution area) and GNU bash alone
  3918 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3919 support requires further installations, e.g. from
  3920 http://fink.sourceforge.net/);
  3921 
  3922 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3923 
  3924 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3925 of 40 MB), cf. ML_OPTIONS;
  3926 
  3927 * system: Proof General keywords specification is now part of the
  3928 Isabelle distribution (see etc/isar-keywords.el);
  3929 
  3930 * system: support for persistent Proof General sessions (refrain from
  3931 outdating all loaded theories on startup); user may create writable
  3932 logic images like this: ``isabelle -q HOL Test'';
  3933 
  3934 * system: smart selection of Isabelle process versus Isabelle
  3935 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3936 run both "isabelle" and "Isabelle" even if file names are badly
  3937 damaged (executable inspects the case of the first letter of its own
  3938 name); added separate "isabelle-process" and "isabelle-interface";
  3939 
  3940 * system: refrain from any attempt at filtering input streams; no
  3941 longer support ``8bit'' encoding of old isabelle font, instead proper
  3942 iso-latin characters may now be used; the related isatools
  3943 "symbolinput" and "nonascii" have disappeared as well;
  3944 
  3945 * system: removed old "xterm" interface (the print modes "xterm" and
  3946 "xterm_color" are still available for direct use in a suitable
  3947 terminal);
  3948 
  3949 
  3950 
  3951 New in Isabelle99-2 (February 2001)
  3952 -----------------------------------
  3953 
  3954 *** Overview of INCOMPATIBILITIES ***
  3955 
  3956 * HOL: please note that theories in the Library and elsewhere often use the
  3957 new-style (Isar) format; to refer to their theorems in an ML script you must
  3958 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3959 
  3960 * HOL: inductive package no longer splits induction rule aggressively,
  3961 but only as far as specified by the introductions given; the old
  3962 format may be recovered via ML function complete_split_rule or attribute
  3963 'split_rule (complete)';
  3964 
  3965 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3966 gfp_Tarski to gfp_unfold;
  3967 
  3968 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3969 
  3970 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3971 relation); infix "^^" has been renamed "``"; infix "``" has been
  3972 renamed "`"; "univalent" has been renamed "single_valued";
  3973 
  3974 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3975 operation;
  3976 
  3977 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3978 
  3979 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3980 
  3981 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3982 consequence, it is no longer monotonic wrt. the local goal context
  3983 (which is now passed through the inductive cases);
  3984 
  3985 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3986 \<gg> to \<ggreater>;
  3987 
  3988 
  3989 *** Document preparation ***
  3990 
  3991 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3992 available: are "it" for near math-mode best-style output, "sl" for
  3993 slanted text style, and "tt" for plain type-writer; if no
  3994 \isabellestyle command is given, output is according to slanted
  3995 type-writer);
  3996 
  3997 * support sub/super scripts (for single symbols only), input syntax is
  3998 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3999 
  4000 * some more standard symbols; see Appendix A of the system manual for
  4001 the complete list of symbols defined in isabellesym.sty;
  4002 
  4003 * improved isabelle style files; more abstract symbol implementation
  4004 (should now use \isamath{...} and \isatext{...} in custom symbol
  4005 definitions);
  4006 
  4007 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4008 state; Note that presentation of goal states does not conform to
  4009 actual human-readable proof documents.  Please do not include goal
  4010 states into document output unless you really know what you are doing!
  4011 
  4012 * proper indentation of antiquoted output with proportional LaTeX
  4013 fonts;
  4014 
  4015 * no_document ML operator temporarily disables LaTeX document
  4016 generation;
  4017 
  4018 * isatool unsymbolize tunes sources for plain ASCII communication;
  4019 
  4020 
  4021 *** Isar ***
  4022 
  4023 * Pure: Isar now suffers initial goal statements to contain unbound
  4024 schematic variables (this does not conform to actual readable proof
  4025 documents, due to unpredictable outcome and non-compositional proof
  4026 checking); users who know what they are doing may use schematic goals
  4027 for Prolog-style synthesis of proven results;
  4028 
  4029 * Pure: assumption method (an implicit finishing) now handles actual
  4030 rules as well;
  4031 
  4032 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4033 initial goal, declare "that" only as Pure intro (only for single
  4034 steps); the "that" rule assumption may now be involved in implicit
  4035 finishing, thus ".." becomes a feasible for trivial obtains;
  4036 
  4037 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4038 instance proofs may be performed by "..";
  4039 
  4040 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4041 statements as well;
  4042 
  4043 * Pure: more robust selection of calculational rules;
  4044 
  4045 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4046 rule (as well as the assumption rule);
  4047 
  4048 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4049 lemmas, using the graph browser tool;
  4050 
  4051 * Pure: predict failure of "show" in interactive mode;
  4052 
  4053 * Pure: 'thms_containing' now takes actual terms as arguments;
  4054 
  4055 * HOL: improved method 'induct' --- now handles non-atomic goals
  4056 (potential INCOMPATIBILITY); tuned error handling;
  4057 
  4058 * HOL: cases and induct rules now provide explicit hints about the
  4059 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4060 any remaining facts are inserted into the goal verbatim;
  4061 
  4062 * HOL: local contexts (aka cases) may now contain term bindings as
  4063 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4064 the result to be shown in each case;
  4065 
  4066 * HOL: added 'recdef_tc' command;
  4067 
  4068 * isatool convert assists in eliminating legacy ML scripts;
  4069 
  4070 
  4071 *** HOL ***
  4072 
  4073 * HOL/Library: a collection of generic theories to be used together
  4074 with main HOL; the theory loader path already includes this directory
  4075 by default; the following existing theories have been moved here:
  4076 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4077 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4078 
  4079 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4080 modelling and verification task performed in Isabelle/HOL +
  4081 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4082 
  4083 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4084 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4085 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4086 'domain', this makes the theory consistent with mathematical
  4087 literature;
  4088 
  4089 * HOL basics: added overloaded operations "inverse" and "divide"
  4090 (infix "/"), syntax for generic "abs" operation, generic summation
  4091 operator \<Sum>;
  4092 
  4093 * HOL/typedef: simplified package, provide more useful rules (see also
  4094 HOL/subset.thy);
  4095 
  4096 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4097 now expressed as a proper nested rule (old-style tactic scripts may
  4098 require atomize_strip_tac to cope with non-atomic premises);
  4099 
  4100 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4101 to "split_conv" (old name still available for compatibility);
  4102 
  4103 * HOL: improved concrete syntax for strings (e.g. allows translation
  4104 rules with string literals);
  4105 
  4106 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4107  and Fleuriot's mechanization of analysis, including the transcendental
  4108  functions for the reals;
  4109 
  4110 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4111 
  4112 
  4113 *** CTT ***
  4114 
  4115 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4116 "lam" is displayed as TWO lambda-symbols
  4117 
  4118 * CTT: theory Main now available, containing everything (that is, Bool
  4119 and Arith);
  4120 
  4121 
  4122 *** General ***
  4123 
  4124 * Pure: the Simplifier has been implemented properly as a derived rule
  4125 outside of the actual kernel (at last!); the overall performance
  4126 penalty in practical applications is about 50%, while reliability of
  4127 the Isabelle inference kernel has been greatly improved;
  4128 
  4129 * print modes "brackets" and "no_brackets" control output of nested =>
  4130 (types) and ==> (props); the default behaviour is "brackets";
  4131 
  4132 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4133 as assumptions as well;
  4134 
  4135 * system: support Poly/ML 4.0;
  4136 
  4137 * system: isatool install handles KDE version 1 or 2;
  4138 
  4139 
  4140 
  4141 New in Isabelle99-1 (October 2000)
  4142 ----------------------------------
  4143 
  4144 *** Overview of INCOMPATIBILITIES ***
  4145 
  4146 * HOL: simplification of natural numbers is much changed; to partly
  4147 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4148 issue the following ML commands:
  4149 
  4150   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4151   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4152 
  4153 * HOL: simplification no longer dives into case-expressions; this is
  4154 controlled by "t.weak_case_cong" for each datatype t;
  4155 
  4156 * HOL: nat_less_induct renamed to less_induct;
  4157 
  4158 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4159 fixsome to patch .thy and .ML sources automatically;
  4160 
  4161   select_equality  -> some_equality
  4162   select_eq_Ex     -> some_eq_ex
  4163   selectI2EX       -> someI2_ex
  4164   selectI2         -> someI2
  4165   selectI          -> someI
  4166   select1_equality -> some1_equality
  4167   Eps_sym_eq       -> some_sym_eq_trivial
  4168   Eps_eq           -> some_eq_trivial
  4169 
  4170 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4171 
  4172 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4173 instead);
  4174 
  4175 * HOL: the recursion equations generated by 'recdef' are now called
  4176 f.simps instead of f.rules;
  4177 
  4178 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4179 
  4180 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4181 sometimes be needed;
  4182 
  4183 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4184 
  4185 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4186 
  4187 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4188 product is now "<*>" instead of "Times"; the lexicographic product is
  4189 now "<*lex*>" instead of "**";
  4190 
  4191 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4192 of main HOL, but was unused); better use HOL's datatype package;
  4193 
  4194 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4195 the old syntax may be recovered as follows:
  4196 
  4197   syntax (symbols)
  4198     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4199       (infixl "\\<oplus>" 100)
  4200 
  4201 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4202 
  4203 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4204 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4205 internally;
  4206 
  4207 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4208 changed from A/r to A//r;
  4209 
  4210 * ZF: new treatment of arithmetic (nat & int) may break some old
  4211 proofs;
  4212 
  4213 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4214 rulify -> rule_format, elimify -> elim_format, ...);
  4215 
  4216 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4217 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4218 should have to change intro!! to intro? only); replaced "delrule" by
  4219 "rule del";
  4220 
  4221 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4222 
  4223 * Provers: strengthened force_tac by using new first_best_tac;
  4224 
  4225 * LaTeX document preparation: several changes of isabelle.sty (see
  4226 lib/texinputs);
  4227 
  4228 
  4229 *** Document preparation ***
  4230 
  4231 * formal comments (text blocks etc.) in new-style theories may now
  4232 contain antiquotations of thm/prop/term/typ/text to be presented
  4233 according to latex print mode; concrete syntax is like this:
  4234 @{term[show_types] "f(x) = a + x"};
  4235 
  4236 * isatool mkdir provides easy setup of Isabelle session directories,
  4237 including proper document sources;
  4238 
  4239 * generated LaTeX sources are now deleted after successful run
  4240 (isatool document -c); may retain a copy somewhere else via -D option
  4241 of isatool usedir;
  4242 
  4243 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4244 style files, achieving self-contained LaTeX sources and simplifying
  4245 LaTeX debugging;
  4246 
  4247 * old-style theories now produce (crude) LaTeX output as well;
  4248 
  4249 * browser info session directories are now self-contained (may be put
  4250 on WWW server seperately); improved graphs of nested sessions; removed
  4251 graph for 'all sessions';
  4252 
  4253 * several improvements in isabelle style files; \isabellestyle{it}
  4254 produces fake math mode output; \isamarkupheader is now \section by
  4255 default; see lib/texinputs/isabelle.sty etc.;
  4256 
  4257 
  4258 *** Isar ***
  4259 
  4260 * Isar/Pure: local results and corresponding term bindings are now
  4261 subject to Hindley-Milner polymorphism (similar to ML); this
  4262 accommodates incremental type-inference very nicely;
  4263 
  4264 * Isar/Pure: new derived language element 'obtain' supports
  4265 generalized existence reasoning;
  4266 
  4267 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4268 support accumulation of results, without applying any rules yet;
  4269 useful to collect intermediate results without explicit name
  4270 references, and for use with transitivity rules with more than 2
  4271 premises;
  4272 
  4273 * Isar/Pure: scalable support for case-analysis type proofs: new
  4274 'case' language element refers to local contexts symbolically, as
  4275 produced by certain proof methods; internally, case names are attached
  4276 to theorems as "tags";
  4277 
  4278 * Isar/Pure: theory command 'hide' removes declarations from
  4279 class/type/const name spaces;
  4280 
  4281 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4282 indicate potential overloading;
  4283 
  4284 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4285 
  4286 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4287 "{a,b,c}" instead of {a,b,c};
  4288 
  4289 * Isar/Pure now provides its own version of intro/elim/dest
  4290 attributes; useful for building new logics, but beware of confusion
  4291 with the version in Provers/classical;
  4292 
  4293 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4294 case name 'antecedent';
  4295 
  4296 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4297 to the current context is now done automatically);
  4298 
  4299 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4300 for definining proof methods in ML;
  4301 
  4302 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4303 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4304 most cases, one should have to change intro!! to intro? only);
  4305 replaced "delrule" by "rule del";
  4306 
  4307 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4308 'symmetric' attribute (the latter supercedes [RS sym]);
  4309 
  4310 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4311 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4312 well (including splits);
  4313 
  4314 * Isar/Provers: Simplifier and Classical methods now support all kind
  4315 of modifiers used in the past, including 'cong', 'iff', etc.
  4316 
  4317 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4318 of Simplifier and Classical reasoner);
  4319 
  4320 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4321 now support named cases; major packages (inductive, datatype, primrec,
  4322 recdef) support case names and properly name parameters;
  4323 
  4324 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4325 monotonicity conditions are extracted to be proven at end of
  4326 calculations;
  4327 
  4328 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4329 method anyway;
  4330 
  4331 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4332 split_if split_if_asm; datatype package provides theorems foo.splits =
  4333 foo.split foo.split_asm for each datatype;
  4334 
  4335 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4336 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4337 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4338 use "(cases (simplified))" method in proper proof texts);
  4339 
  4340 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4341 
  4342 * Isar: names of theorems etc. may be natural numbers as well;
  4343 
  4344 * Isar: 'pr' command: optional arguments for goals_limit and
  4345 ProofContext.prems_limit; no longer prints theory contexts, but only
  4346 proof states;
  4347 
  4348 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4349 additional print modes to be specified; e.g. "pr(latex)" will print
  4350 proof state according to the Isabelle LaTeX style;
  4351 
  4352 * Isar: improved support for emulating tactic scripts, including proof
  4353 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4354 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4355 (for HOL datatypes);
  4356 
  4357 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4358 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4359 'proof method scripts' have to be in depth-first order;
  4360 
  4361 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4362 
  4363 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4364 should instead use individual commands for printing items
  4365 (print_commands, print_methods etc.);
  4366 
  4367 * Isar: added 'nothing' --- the empty list of theorems;
  4368 
  4369 
  4370 *** HOL ***
  4371 
  4372 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4373 corresponding virtual machine and a specification of its bytecode
  4374 verifier and a lightweight bytecode verifier, including proofs of
  4375 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4376 Cornelia Pusch (see also the homepage of project Bali at
  4377 http://isabelle.in.tum.de/Bali/);
  4378 
  4379 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4380 Clemens Ballarin;
  4381 
  4382 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4383 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4384 Rasmussen;
  4385 
  4386 * HOL/Lattice: fundamental concepts of lattice theory and order
  4387 structures, including duals, properties of bounds versus algebraic
  4388 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4389 Theorem for complete lattices etc.; may also serve as a demonstration
  4390 for abstract algebraic reasoning using axiomatic type classes, and
  4391 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4392 
  4393 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4394 von Oheimb;
  4395 
  4396 * HOL/IMPP: extension of IMP with local variables and mutually
  4397 recursive procedures, by David von Oheimb;
  4398 
  4399 * HOL/Lambda: converted into new-style theory and document;
  4400 
  4401 * HOL/ex/Multiquote: example of multiple nested quotations and
  4402 anti-quotations -- basically a generalized version of de-Bruijn
  4403 representation; very useful in avoiding lifting of operations;
  4404 
  4405 * HOL/record: added general record equality rule to simpset; fixed
  4406 select-update simplification procedure to handle extended records as
  4407 well; admit "r" as field name;
  4408 
  4409 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4410 other numeric types and also as the identity of groups, rings, etc.;
  4411 
  4412 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4413 Types nat and int belong to this axclass;
  4414 
  4415 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4416    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4417    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4418   two terms #m*u and #n*u are replaced by #(m+n)*u
  4419     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4420   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4421     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4422 
  4423 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4424 powerful prover for predicate logic but knows nothing of clasets; see
  4425 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4426 
  4427 * HOL: new version of "case_tac" subsumes both boolean case split and
  4428 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4429 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4430 
  4431 * HOL: simplification no longer dives into case-expressions: only the
  4432 selector expression is simplified, but not the remaining arms; to
  4433 enable full simplification of case-expressions for datatype t, you may
  4434 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4435 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4436 
  4437 * HOL/recdef: the recursion equations generated by 'recdef' for
  4438 function 'f' are now called f.simps instead of f.rules; if all
  4439 termination conditions are proved automatically, these simplification
  4440 rules are added to the simpset, as in primrec; rules may be named
  4441 individually as well, resulting in a separate list of theorems for
  4442 each equation;
  4443 
  4444 * HOL/While is a new theory that provides a while-combinator. It
  4445 permits the definition of tail-recursive functions without the
  4446 provision of a termination measure. The latter is necessary once the
  4447 invariant proof rule for while is applied.
  4448 
  4449 * HOL: new (overloaded) notation for the set of elements below/above
  4450 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4451 
  4452 * HOL: theorems impI, allI, ballI bound as "strip";
  4453 
  4454 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4455 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4456 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4457 
  4458 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4459 
  4460 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4461 main HOL, but was unused);
  4462 
  4463 * HOL: fewer consts declared as global (e.g. have to refer to
  4464 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4465 
  4466 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4467 in case of overlap with user translations (e.g. judgements over
  4468 tuples); (note that the underlying logical represenation is still
  4469 bogus);
  4470 
  4471 
  4472 *** ZF ***
  4473 
  4474 * ZF: simplification automatically cancels common terms in arithmetic
  4475 expressions over nat and int;
  4476 
  4477 * ZF: new treatment of nat to minimize type-checking: all operators
  4478 coerce their operands to a natural number using the function natify,
  4479 making the algebraic laws unconditional;
  4480 
  4481 * ZF: as above, for int: operators coerce their operands to an integer
  4482 using the function intify;
  4483 
  4484 * ZF: the integer library now contains many of the usual laws for the
  4485 orderings, including $<=, and monotonicity laws for $+ and $*;
  4486 
  4487 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4488 simplification;
  4489 
  4490 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4491 to the simplifier and classical reasoner simultaneously;
  4492 
  4493 
  4494 *** General ***
  4495 
  4496 * Provers: blast_tac now handles actual object-logic rules as
  4497 assumptions; note that auto_tac uses blast_tac internally as well;
  4498 
  4499 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4500 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4501 
  4502 * Provers: delrules now handles destruct rules as well (no longer need
  4503 explicit make_elim);
  4504 
  4505 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4506   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4507 use instead the strong form,
  4508   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4509 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4510 from destruct-rules;
  4511 
  4512 * Provers: Simplifier.easy_setup provides a fast path to basic
  4513 Simplifier setup for new object-logics;
  4514 
  4515 * Pure: AST translation rules no longer require constant head on LHS;
  4516 
  4517 * Pure: improved name spaces: ambiguous output is qualified; support
  4518 for hiding of names;
  4519 
  4520 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4521 XSYMBOL_HOME; no longer need to do manual configuration in most
  4522 situations;
  4523 
  4524 * system: compression of ML heaps images may now be controlled via -c
  4525 option of isabelle and isatool usedir (currently only observed by
  4526 Poly/ML);
  4527 
  4528 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4529 useful for remote X11);
  4530 
  4531 * system: provide TAGS file for Isabelle sources;
  4532 
  4533 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4534 order;
  4535 
  4536 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4537 timing flag supersedes proof_timing and Toplevel.trace;
  4538 
  4539 * ML: new combinators |>> and |>>> for incremental transformations
  4540 with secondary results (e.g. certain theory extensions):
  4541 
  4542 * ML: PureThy.add_defs gets additional argument to indicate potential
  4543 overloading (usually false);
  4544 
  4545 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4546 results;
  4547 
  4548 
  4549 
  4550 New in Isabelle99 (October 1999)
  4551 --------------------------------
  4552 
  4553 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4554 
  4555 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4556 are no longer simplified.  (This allows the simplifier to unfold recursive
  4557 functional programs.)  To restore the old behaviour, declare
  4558 
  4559     Delcongs [if_weak_cong];
  4560 
  4561 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4562 complement;
  4563 
  4564 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4565 
  4566 * HOL/datatype: mutual_induct_tac no longer exists --
  4567   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  4568 
  4569 * HOL/typedef: fixed type inference for representing set; type
  4570 arguments now have to occur explicitly on the rhs as type constraints;
  4571 
  4572 * ZF: The con_defs part of an inductive definition may no longer refer
  4573 to constants declared in the same theory;
  4574 
  4575 * HOL, ZF: the function mk_cases, generated by the inductive
  4576 definition package, has lost an argument.  To simplify its result, it
  4577 uses the default simpset instead of a supplied list of theorems.
  4578 
  4579 * HOL/List: the constructors of type list are now Nil and Cons;
  4580 
  4581 * Simplifier: the type of the infix ML functions
  4582         setSSolver addSSolver setSolver addSolver
  4583 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4584 for packaging solvers. A solver is created via
  4585         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4586 where the string argument is only a comment.
  4587 
  4588 
  4589 *** Proof tools ***
  4590 
  4591 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4592 decision procedure for linear arithmetic. Currently it is used for
  4593 types `nat', `int', and `real' in HOL (see below); it can, should and
  4594 will be instantiated for other types and logics as well.
  4595 
  4596 * The simplifier now accepts rewrite rules with flexible heads, eg
  4597      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4598   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4599   matching.
  4600 
  4601 
  4602 *** General ***
  4603 
  4604 * New Isabelle/Isar subsystem provides an alternative to traditional
  4605 tactical theorem proving; together with the ProofGeneral/isar user
  4606 interface it offers an interactive environment for developing human
  4607 readable proof documents (Isar == Intelligible semi-automated
  4608 reasoning); for further information see isatool doc isar-ref,
  4609 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  4610 
  4611 * improved and simplified presentation of theories: better HTML markup
  4612 (including colors), graph views in several sizes; isatool usedir now
  4613 provides a proper interface for user theories (via -P option); actual
  4614 document preparation based on (PDF)LaTeX is available as well (for
  4615 new-style theories only); see isatool doc system for more information;
  4616 
  4617 * native support for Proof General, both for classic Isabelle and
  4618 Isabelle/Isar;
  4619 
  4620 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  4621 using the graph browser tool;
  4622 
  4623 * Isabelle manuals now also available as PDF;
  4624 
  4625 * theory loader rewritten from scratch (may not be fully
  4626 bug-compatible); old loadpath variable has been replaced by show_path,
  4627 add_path, del_path, reset_path functions; new operations such as
  4628 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  4629 isatool doc ref);
  4630 
  4631 * improved isatool install: option -k creates KDE application icon,
  4632 option -p DIR installs standalone binaries;
  4633 
  4634 * added ML_PLATFORM setting (useful for cross-platform installations);
  4635 more robust handling of platform specific ML images for SML/NJ;
  4636 
  4637 * the settings environment is now statically scoped, i.e. it is never
  4638 created again in sub-processes invoked from isabelle, isatool, or
  4639 Isabelle;
  4640 
  4641 * path element specification '~~' refers to '$ISABELLE_HOME';
  4642 
  4643 * in locales, the "assumes" and "defines" parts may be omitted if
  4644 empty;
  4645 
  4646 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4647 long arrows);
  4648 
  4649 * new print_mode "HTML";
  4650 
  4651 * new flag show_tags controls display of tags of theorems (which are
  4652 basically just comments that may be attached by some tools);
  4653 
  4654 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4655 mode and goal output format:
  4656 
  4657 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4658 244c244
  4659 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4660 ---
  4661 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4662 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4663 181c181
  4664 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4665 ---
  4666 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4667 
  4668 * function bind_thms stores lists of theorems (cf. bind_thm);
  4669 
  4670 * new shorthand tactics ftac, eatac, datac, fatac;
  4671 
  4672 * qed (and friends) now accept "" as result name; in that case the
  4673 theorem is not stored, but proper checks and presentation of the
  4674 result still apply;
  4675 
  4676 * theorem database now also indexes constants "Trueprop", "all",
  4677 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4678 
  4679 
  4680 *** HOL ***
  4681 
  4682 ** HOL arithmetic **
  4683 
  4684 * There are now decision procedures for linear arithmetic over nat and
  4685 int:
  4686 
  4687 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4688 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4689 are treated as atomic; subformulae not involving type `nat' or `int'
  4690 are ignored; quantified subformulae are ignored unless they are
  4691 positive universal or negative existential. The tactic has to be
  4692 invoked by hand and can be a little bit slow. In particular, the
  4693 running time is exponential in the number of occurrences of `min' and
  4694 `max', and `-' on `nat'.
  4695 
  4696 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4697 (negated) (in)equalities among the premises and the conclusion into
  4698 account (i.e. no compound formulae) and does not know about `min' and
  4699 `max', and `-' on `nat'. It is fast and is used automatically by the
  4700 simplifier.
  4701 
  4702 NB: At the moment, these decision procedures do not cope with mixed
  4703 nat/int formulae where the two parts interact, such as `m < n ==>
  4704 int(m) < int(n)'.
  4705 
  4706 * HOL/Numeral provides a generic theory of numerals (encoded
  4707 efficiently as bit strings); setup for types nat/int/real is in place;
  4708 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4709 int, existing theories and proof scripts may require a few additional
  4710 type constraints;
  4711 
  4712 * integer division and remainder can now be performed on constant
  4713 arguments;
  4714 
  4715 * many properties of integer multiplication, division and remainder
  4716 are now available;
  4717 
  4718 * An interface to the Stanford Validity Checker (SVC) is available through the
  4719 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4720 are proved automatically.  SVC must be installed separately, and its results
  4721 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4722 invocation of the underlying oracle).  For SVC see
  4723   http://verify.stanford.edu/SVC
  4724 
  4725 * IsaMakefile: the HOL-Real target now builds an actual image;
  4726 
  4727 
  4728 ** HOL misc **
  4729 
  4730 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4731 (in Isabelle/Isar) -- by Gertrud Bauer;
  4732 
  4733 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4734 analysis for assembly languages with subtypes;
  4735 
  4736 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4737 -- avoids syntactic ambiguities and treats state, transition, and
  4738 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4739 changed syntax and (many) tactics;
  4740 
  4741 * HOL/inductive: Now also handles more general introduction rules such
  4742   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4743   theorems are now maintained within the theory (maintained via the
  4744   "mono" attribute);
  4745 
  4746 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4747   (using function types) such as
  4748 
  4749   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4750 
  4751 * HOL/record: record_simproc (part of the default simpset) takes care
  4752 of selectors applied to updated records; record_split_tac is no longer
  4753 part of the default claset; update_defs may now be removed from the
  4754 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4755 
  4756   claset_ref () := claset() addSWrapper record_split_wrapper;
  4757   Delsimprocs [record_simproc]
  4758 
  4759 * HOL/typedef: fixed type inference for representing set; type
  4760 arguments now have to occur explicitly on the rhs as type constraints;
  4761 
  4762 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4763 names rather than an ML expression;
  4764 
  4765 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4766 supplied later.  Program schemes can be defined, such as
  4767     "While B C s = (if B s then While B C (C s) else s)"
  4768 where the well-founded relation can be chosen after B and C have been given.
  4769 
  4770 * HOL/List: the constructors of type list are now Nil and Cons;
  4771 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4772 course, ML tools referring to List.list.op # etc. have to be adapted;
  4773 
  4774 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4775 disabled by default; run isabelle with option -m HOL to get back to
  4776 the original Gordon/HOL-style output;
  4777 
  4778 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4779 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4780 
  4781 * HOL basic syntax simplified (more orthogonal): all variants of
  4782 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4783 Eps operator is provided as well: "SOME x. P[x]";
  4784 
  4785 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4786 
  4787 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4788 thus available for user theories;
  4789 
  4790 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4791 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4792 time;
  4793 
  4794 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4795 several times and then mp;
  4796 
  4797 
  4798 *** LK ***
  4799 
  4800 * the notation <<...>> is now available as a notation for sequences of
  4801 formulas;
  4802 
  4803 * the simplifier is now installed
  4804 
  4805 * the axiom system has been generalized (thanks to Soren Heilmann)
  4806 
  4807 * the classical reasoner now has a default rule database
  4808 
  4809 
  4810 *** ZF ***
  4811 
  4812 * new primrec section allows primitive recursive functions to be given
  4813 directly (as in HOL) over datatypes and the natural numbers;
  4814 
  4815 * new tactics induct_tac and exhaust_tac for induction (or case
  4816 analysis) over datatypes and the natural numbers;
  4817 
  4818 * the datatype declaration of type T now defines the recursor T_rec;
  4819 
  4820 * simplification automatically does freeness reasoning for datatype
  4821 constructors;
  4822 
  4823 * automatic type-inference, with AddTCs command to insert new
  4824 type-checking rules;
  4825 
  4826 * datatype introduction rules are now added as Safe Introduction rules
  4827 to the claset;
  4828 
  4829 * the syntax "if P then x else y" is now available in addition to
  4830 if(P,x,y);
  4831 
  4832 
  4833 *** Internal programming interfaces ***
  4834 
  4835 * tuned simplifier trace output; new flag debug_simp;
  4836 
  4837 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4838 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4839 
  4840 * AxClass.axclass_tac lost the theory argument;
  4841 
  4842 * tuned current_goals_markers semantics: begin / end goal avoids
  4843 printing empty lines;
  4844 
  4845 * removed prs and prs_fn hook, which was broken because it did not
  4846 include \n in its semantics, forcing writeln to add one
  4847 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4848 string -> unit if you really want to output text without newline;
  4849 
  4850 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4851 plain output, interface builders may have to enable 'isabelle_font'
  4852 mode to get Isabelle font glyphs as before;
  4853 
  4854 * refined token_translation interface; INCOMPATIBILITY: output length
  4855 now of type real instead of int;
  4856 
  4857 * theory loader actions may be traced via new ThyInfo.add_hook
  4858 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4859 your own database of information attached to *whole* theories -- as
  4860 opposed to intra-theory data slots offered via TheoryDataFun;
  4861 
  4862 * proper handling of dangling sort hypotheses (at last!);
  4863 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4864 extra sort hypotheses that can be witnessed from the type signature;
  4865 the force_strip_shyps flag is gone, any remaining shyps are simply
  4866 left in the theorem (with a warning issued by strip_shyps_warning);
  4867 
  4868 
  4869 
  4870 New in Isabelle98-1 (October 1998)
  4871 ----------------------------------
  4872 
  4873 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4874 
  4875 * several changes of automated proof tools;
  4876 
  4877 * HOL: major changes to the inductive and datatype packages, including
  4878 some minor incompatibilities of theory syntax;
  4879 
  4880 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4881 called `inj_on';
  4882 
  4883 * HOL: removed duplicate thms in Arith:
  4884   less_imp_add_less  should be replaced by  trans_less_add1
  4885   le_imp_add_le      should be replaced by  trans_le_add1
  4886 
  4887 * HOL: unary minus is now overloaded (new type constraints may be
  4888 required);
  4889 
  4890 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4891 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4892 now taken as an integer constant.
  4893 
  4894 * Pure: ML function 'theory_of' renamed to 'theory';
  4895 
  4896 
  4897 *** Proof tools ***
  4898 
  4899 * Simplifier:
  4900   1. Asm_full_simp_tac is now more aggressive.
  4901      1. It will sometimes reorient premises if that increases their power to
  4902         simplify.
  4903      2. It does no longer proceed strictly from left to right but may also
  4904         rotate premises to achieve further simplification.
  4905      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4906      old Asm_full_simp_tac in that it does not rotate premises.
  4907   2. The simplifier now knows a little bit about nat-arithmetic.
  4908 
  4909 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4910 allows for selected deletion of wrappers, by introduction of names for
  4911 wrapper functionals.  This implies that addbefore, addSbefore,
  4912 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4913 and that adding two tactics with the same name overwrites the first
  4914 one (emitting a warning).
  4915   type wrapper = (int -> tactic) -> (int -> tactic)
  4916   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4917   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4918   delWrapper, delSWrapper: claset *  string            -> claset
  4919   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4920 
  4921 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4922 semantics; addbefore now affects only the unsafe part of step_tac
  4923 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4924 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4925 by Force_tac;
  4926 
  4927 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4928 compWrapper; added safe wrapper (and access functions for it);
  4929 
  4930 * HOL/split_all_tac is now much faster and fails if there is nothing
  4931 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4932 and the names of the automatically generated variables have changed.
  4933 split_all_tac has moved within claset() from unsafe wrappers to safe
  4934 wrappers, which means that !!-bound variables are split much more
  4935 aggressively, and safe_tac and clarify_tac now split such variables.
  4936 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4937 Note: the same holds for record_split_tac, which does the job of
  4938 split_all_tac for record fields.
  4939 
  4940 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4941 permanently to the default simpset using Addsplits just like
  4942 Addsimps. They can be removed via Delsplits just like
  4943 Delsimps. Lower-case versions are also available.
  4944 
  4945 * HOL/Simplifier: The rule split_if is now part of the default
  4946 simpset. This means that the simplifier will eliminate all occurrences
  4947 of if-then-else in the conclusion of a goal. To prevent this, you can
  4948 either remove split_if completely from the default simpset by
  4949 `Delsplits [split_if]' or remove it in a specific call of the
  4950 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4951 other case splitting rules to/from the default simpset: every datatype
  4952 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4953 t is the name of the datatype).
  4954 
  4955 * Classical reasoner / Simplifier combination: new force_tac (and
  4956 derivatives Force_tac, force) combines rewriting and classical
  4957 reasoning (and whatever other tools) similarly to auto_tac, but is
  4958 aimed to solve the given subgoal completely.
  4959 
  4960 
  4961 *** General ***
  4962 
  4963 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4964 and `goalw': the theory is no longer needed as an explicit argument -
  4965 the current theory context is used; assumptions are no longer returned
  4966 at the ML-level unless one of them starts with ==> or !!; it is
  4967 recommended to convert to these new commands using isatool fixgoal
  4968 (backup your sources first!);
  4969 
  4970 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4971 the current theory context, and 'theory' to lookup stored theories;
  4972 
  4973 * new theory section 'locale' for declaring constants, assumptions and
  4974 definitions that have local scope;
  4975 
  4976 * new theory section 'nonterminals' for purely syntactic types;
  4977 
  4978 * new theory section 'setup' for generic ML setup functions
  4979 (e.g. package initialization);
  4980 
  4981 * the distribution now includes Isabelle icons: see
  4982 lib/logo/isabelle-{small,tiny}.xpm;
  4983 
  4984 * isatool install - install binaries with absolute references to
  4985 ISABELLE_HOME/bin;
  4986 
  4987 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4988 
  4989 * print mode 'emacs' reserved for Isamode;
  4990 
  4991 * support multiple print (ast) translations per constant name;
  4992 
  4993 * theorems involving oracles are now printed with a suffixed [!];
  4994 
  4995 
  4996 *** HOL ***
  4997 
  4998 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4999 
  5000 * HOL/inductive package reorganized and improved: now supports mutual
  5001 definitions such as
  5002 
  5003   inductive EVEN ODD
  5004     intrs
  5005       null "0 : EVEN"
  5006       oddI "n : EVEN ==> Suc n : ODD"
  5007       evenI "n : ODD ==> Suc n : EVEN"
  5008 
  5009 new theorem list "elims" contains an elimination rule for each of the
  5010 recursive sets; inductive definitions now handle disjunctive premises
  5011 correctly (also ZF);
  5012 
  5013 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5014 "mutual_induct" no longer exists - the induction rule is always
  5015 contained in "induct";
  5016 
  5017 
  5018 * HOL/datatype package re-implemented and greatly improved: now
  5019 supports mutually recursive datatypes such as
  5020 
  5021   datatype
  5022     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5023             | SUM ('a aexp) ('a aexp)
  5024             | DIFF ('a aexp) ('a aexp)
  5025             | NUM 'a
  5026   and
  5027     'a bexp = LESS ('a aexp) ('a aexp)
  5028             | AND ('a bexp) ('a bexp)
  5029             | OR ('a bexp) ('a bexp)
  5030 
  5031 as well as indirectly recursive datatypes such as
  5032 
  5033   datatype
  5034     ('a, 'b) term = Var 'a
  5035                   | App 'b ((('a, 'b) term) list)
  5036 
  5037 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5038 induction on mutually / indirectly recursive datatypes.
  5039 
  5040 Primrec equations are now stored in theory and can be accessed via
  5041 <function_name>.simps.
  5042 
  5043 INCOMPATIBILITIES:
  5044 
  5045   - Theories using datatypes must now have theory Datatype as an
  5046     ancestor.
  5047   - The specific <typename>.induct_tac no longer exists - use the
  5048     generic induct_tac instead.
  5049   - natE has been renamed to nat.exhaust - use exhaust_tac
  5050     instead of res_inst_tac ... natE. Note that the variable
  5051     names in nat.exhaust differ from the names in natE, this
  5052     may cause some "fragile" proofs to fail.
  5053   - The theorems split_<typename>_case and split_<typename>_case_asm
  5054     have been renamed to <typename>.split and <typename>.split_asm.
  5055   - Since default sorts of type variables are now handled correctly,
  5056     some datatype definitions may have to be annotated with explicit
  5057     sort constraints.
  5058   - Primrec definitions no longer require function name and type
  5059     of recursive argument.
  5060 
  5061 Consider using isatool fixdatatype to adapt your theories and proof
  5062 scripts to the new package (backup your sources first!).
  5063 
  5064 
  5065 * HOL/record package: considerably improved implementation; now
  5066 includes concrete syntax for record types, terms, updates; theorems
  5067 for surjective pairing and splitting !!-bound record variables; proof
  5068 support is as follows:
  5069 
  5070   1) standard conversions (selectors or updates applied to record
  5071 constructor terms) are part of the standard simpset;
  5072 
  5073   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5074 made part of standard simpset and claset via addIffs;
  5075 
  5076   3) a tactic for record field splitting (record_split_tac) is part of
  5077 the standard claset (addSWrapper);
  5078 
  5079 To get a better idea about these rules you may retrieve them via
  5080 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5081 the name of your record type.
  5082 
  5083 The split tactic 3) conceptually simplifies by the following rule:
  5084 
  5085   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5086 
  5087 Thus any record variable that is bound by meta-all will automatically
  5088 blow up into some record constructor term, consequently the
  5089 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5090 solve record problems automatically.
  5091 
  5092 
  5093 * reorganized the main HOL image: HOL/Integ and String loaded by
  5094 default; theory Main includes everything;
  5095 
  5096 * automatic simplification of integer sums and comparisons, using cancellation;
  5097 
  5098 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5099 
  5100 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5101 
  5102 * many new identities for unions, intersections, set difference, etc.;
  5103 
  5104 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5105 called split_if, split_split, split_sum_case and split_nat_case (to go
  5106 with add/delsplits);
  5107 
  5108 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5109 (?x::unit) = (); this is made part of the default simpset, which COULD
  5110 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5111 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5112 unit_abs_eta_conv is added in order to counter the effect of
  5113 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5114 %u.f();
  5115 
  5116 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5117 makes more sense);
  5118 
  5119 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5120   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5121   disjointness reasoning but breaking a few old proofs.
  5122 
  5123 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5124 to 'converse' from 'inverse' (for compatibility with ZF and some
  5125 literature);
  5126 
  5127 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5128 the well-founded relation;
  5129 
  5130 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5131     Compl A.  The "Compl" syntax remains available as input syntax for this
  5132     release ONLY.
  5133 
  5134 * HOL/Update: new theory of function updates:
  5135     f(a:=b) == %x. if x=a then b else f x
  5136 may also be iterated as in f(a:=b,c:=d,...);
  5137 
  5138 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5139 
  5140 * HOL/List:
  5141   - new function list_update written xs[i:=v] that updates the i-th
  5142     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5143   - new function `upt' written [i..j(] which generates the list
  5144     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5145     bound write [i..j], which is a shorthand for [i..j+1(].
  5146   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5147 
  5148 * HOL/Arith:
  5149   - removed 'pred' (predecessor) function;
  5150   - generalized some theorems about n-1;
  5151   - many new laws about "div" and "mod";
  5152   - new laws about greatest common divisors (see theory ex/Primes);
  5153 
  5154 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5155 instead of "inverse";
  5156 
  5157 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5158   of the multiset ordering;
  5159 
  5160 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5161   (not included by default);
  5162 
  5163 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5164 
  5165 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5166   programs, i.e. different program variables may have different types.
  5167 
  5168 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5169   [previously, this check worked only if the rewrite rule was unconditional]
  5170   Now rew can involve either definitions or equalities (either == or =).
  5171 
  5172 
  5173 *** ZF ***
  5174 
  5175 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5176   only the theorems proved on ZF.ML;
  5177 
  5178 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5179   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5180   disjointness reasoning but breaking a few old proofs.
  5181 
  5182 * ZF/Update: new theory of function updates
  5183     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5184   may also be iterated as in f(a:=b,c:=d,...);
  5185 
  5186 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5187 
  5188 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5189   [previously, this check worked only if the rewrite rule was unconditional]
  5190   Now rew can involve either definitions or equalities (either == or =).
  5191 
  5192 * case_tac provided for compatibility with HOL
  5193     (like the old excluded_middle_tac, but with subgoals swapped)
  5194 
  5195 
  5196 *** Internal programming interfaces ***
  5197 
  5198 * Pure: several new basic modules made available for general use, see
  5199 also src/Pure/README;
  5200 
  5201 * improved the theory data mechanism to support encapsulation (data
  5202 kind name replaced by private Object.kind, acting as authorization
  5203 key); new type-safe user interface via functor TheoryDataFun; generic
  5204 print_data function becomes basically useless;
  5205 
  5206 * removed global_names compatibility flag -- all theory declarations
  5207 are qualified by default;
  5208 
  5209 * module Pure/Syntax now offers quote / antiquote translation
  5210 functions (useful for Hoare logic etc. with implicit dependencies);
  5211 see HOL/ex/Antiquote for an example use;
  5212 
  5213 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5214 cterm -> thm;
  5215 
  5216 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5217 subgoal;
  5218 
  5219 * Display.print_goals function moved to Locale.print_goals;
  5220 
  5221 * standard print function for goals supports current_goals_markers
  5222 variable for marking begin of proof, end of proof, start of goal; the
  5223 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5224 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5225 for example;
  5226 
  5227 
  5228 
  5229 New in Isabelle98 (January 1998)
  5230 --------------------------------
  5231 
  5232 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5233 
  5234 * changed lexical syntax of terms / types: dots made part of long
  5235 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5236 
  5237 * simpset (and claset) reference variable replaced by functions
  5238 simpset / simpset_ref;
  5239 
  5240 * no longer supports theory aliases (via merge) and non-trivial
  5241 implicit merge of thms' signatures;
  5242 
  5243 * most internal names of constants changed due to qualified names;
  5244 
  5245 * changed Pure/Sequence interface (see Pure/seq.ML);
  5246 
  5247 
  5248 *** General Changes ***
  5249 
  5250 * hierachically structured name spaces (for consts, types, axms, thms
  5251 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5252 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5253 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5254 long_names for fully qualified output names; NOTE: ML programs
  5255 (special tactics, packages etc.) referring to internal names may have
  5256 to be adapted to cope with fully qualified names; in case of severe
  5257 backward campatibility problems try setting 'global_names' at compile
  5258 time to have enrything declared within a flat name space; one may also
  5259 fine tune name declarations in theories via the 'global' and 'local'
  5260 section;
  5261 
  5262 * reimplemented the implicit simpset and claset using the new anytype
  5263 data filed in signatures; references simpset:simpset ref etc. are
  5264 replaced by functions simpset:unit->simpset and
  5265 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5266 to patch your ML files accordingly;
  5267 
  5268 * HTML output now includes theory graph data for display with Java
  5269 applet or isatool browser; data generated automatically via isatool
  5270 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5271 
  5272 * defs may now be conditional; improved rewrite_goals_tac to handle
  5273 conditional equations;
  5274 
  5275 * defs now admits additional type arguments, using TYPE('a) syntax;
  5276 
  5277 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5278 creates a new theory node; implicit merge of thms' signatures is
  5279 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5280 transfer:theory->thm->thm in (rare) cases;
  5281 
  5282 * improved handling of draft signatures / theories; draft thms (and
  5283 ctyps, cterms) are automatically promoted to real ones;
  5284 
  5285 * slightly changed interfaces for oracles: admit many per theory, named
  5286 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5287 
  5288 * print_goals: optional output of const types (set show_consts and
  5289 show_types);
  5290 
  5291 * improved output of warnings (###) and errors (***);
  5292 
  5293 * subgoal_tac displays a warning if the new subgoal has type variables;
  5294 
  5295 * removed old README and Makefiles;
  5296 
  5297 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5298 
  5299 * removed obsolete init_pps and init_database;
  5300 
  5301 * deleted the obsolete tactical STATE, which was declared by
  5302     fun STATE tacfun st = tacfun st st;
  5303 
  5304 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5305 (which abbreviates $HOME);
  5306 
  5307 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5308 use isatool fixseq to adapt your ML programs (this works for fully
  5309 qualified references to the Sequence structure only!);
  5310 
  5311 * use_thy no longer requires writable current directory; it always
  5312 reloads .ML *and* .thy file, if either one is out of date;
  5313 
  5314 
  5315 *** Classical Reasoner ***
  5316 
  5317 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5318 tactics that use classical reasoning to simplify a subgoal without
  5319 splitting it into several subgoals;
  5320 
  5321 * Safe_tac: like safe_tac but uses the default claset;
  5322 
  5323 
  5324 *** Simplifier ***
  5325 
  5326 * added simplification meta rules:
  5327     (asm_)(full_)simplify: simpset -> thm -> thm;
  5328 
  5329 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5330 logics (again);
  5331 
  5332 * added prems argument to simplification procedures;
  5333 
  5334 * HOL, FOL, ZF: added infix function `addsplits':
  5335   instead of `<simpset> setloop (split_tac <thms>)'
  5336   you can simply write `<simpset> addsplits <thms>'
  5337 
  5338 
  5339 *** Syntax ***
  5340 
  5341 * TYPE('a) syntax for type reflection terms;
  5342 
  5343 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5344 
  5345 * pretty printer: changed order of mixfix annotation preference (again!);
  5346 
  5347 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5348 
  5349 
  5350 *** HOL ***
  5351 
  5352 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5353   with `addloop' of the simplifier to faciliate case splitting in premises.
  5354 
  5355 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5356 
  5357 * HOL/Auth: new protocol proofs including some for the Internet
  5358   protocol TLS;
  5359 
  5360 * HOL/Map: new theory of `maps' a la VDM;
  5361 
  5362 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5363 cancelling out common nat summands from =, <, <= (in)equalities, or
  5364 differences; simplification procedures nat_cancel_factor for
  5365 cancelling common factor from =, <, <= (in)equalities over natural
  5366 sums; nat_cancel contains both kinds of procedures, it is installed by
  5367 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5368 
  5369 * HOL/simplifier: terms of the form
  5370   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5371   are rewritten to
  5372   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5373   and those of the form
  5374   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5375   are rewritten to
  5376   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5377 
  5378 * HOL/datatype
  5379   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5380 
  5381   P(t_case f1 ... fn x) =
  5382      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5383         ...
  5384        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5385      )
  5386 
  5387   and a theorem `split_t_case_asm' of the form
  5388 
  5389   P(t_case f1 ... fn x) =
  5390     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5391         ...
  5392        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5393      )
  5394   which can be added to a simpset via `addsplits'. The existing theorems
  5395   expand_list_case and expand_option_case have been renamed to
  5396   split_list_case and split_option_case.
  5397 
  5398 * HOL/Arithmetic:
  5399   - `pred n' is automatically converted to `n-1'.
  5400     Users are strongly encouraged not to use `pred' any longer,
  5401     because it will disappear altogether at some point.
  5402   - Users are strongly encouraged to write "0 < n" rather than
  5403     "n ~= 0". Theorems and proof tools have been modified towards this
  5404     `standard'.
  5405 
  5406 * HOL/Lists:
  5407   the function "set_of_list" has been renamed "set" (and its theorems too);
  5408   the function "nth" now takes its arguments in the reverse order and
  5409   has acquired the infix notation "!" as in "xs!n".
  5410 
  5411 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5412 
  5413 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5414   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5415 
  5416 * HOL/record: extensible records with schematic structural subtyping
  5417 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5418 still lacks various theorems and concrete record syntax;
  5419 
  5420 
  5421 *** HOLCF ***
  5422 
  5423 * removed "axioms" and "generated by" sections;
  5424 
  5425 * replaced "ops" section by extended "consts" section, which is capable of
  5426   handling the continuous function space "->" directly;
  5427 
  5428 * domain package:
  5429   . proves theorems immediately and stores them in the theory,
  5430   . creates hierachical name space,
  5431   . now uses normal mixfix annotations (instead of cinfix...),
  5432   . minor changes to some names and values (for consistency),
  5433   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5434   . separator between mutual domain defs: changed "," to "and",
  5435   . improved handling of sort constraints;  now they have to
  5436     appear on the left-hand side of the equations only;
  5437 
  5438 * fixed LAM <x,y,zs>.b syntax;
  5439 
  5440 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5441 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5442 
  5443 
  5444 *** FOL and ZF ***
  5445 
  5446 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5447   with `addloop' of the simplifier to faciliate case splitting in premises.
  5448 
  5449 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5450 in HOL, they strip ALL and --> from proved theorems;
  5451 
  5452 
  5453 
  5454 New in Isabelle94-8 (May 1997)
  5455 ------------------------------
  5456 
  5457 *** General Changes ***
  5458 
  5459 * new utilities to build / run / maintain Isabelle etc. (in parts
  5460 still somewhat experimental); old Makefiles etc. still functional;
  5461 
  5462 * new 'Isabelle System Manual';
  5463 
  5464 * INSTALL text, together with ./configure and ./build scripts;
  5465 
  5466 * reimplemented type inference for greater efficiency, better error
  5467 messages and clean internal interface;
  5468 
  5469 * prlim command for dealing with lots of subgoals (an easier way of
  5470 setting goals_limit);
  5471 
  5472 
  5473 *** Syntax ***
  5474 
  5475 * supports alternative (named) syntax tables (parser and pretty
  5476 printer); internal interface is provided by add_modesyntax(_i);
  5477 
  5478 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5479 be used in conjunction with the Isabelle symbol font; uses the
  5480 "symbols" syntax table;
  5481 
  5482 * added token_translation interface (may translate name tokens in
  5483 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5484 the current print_mode); IMPORTANT: user print translation functions
  5485 are responsible for marking newly introduced bounds
  5486 (Syntax.mark_boundT);
  5487 
  5488 * token translations for modes "xterm" and "xterm_color" that display
  5489 names in bold, underline etc. or colors (which requires a color
  5490 version of xterm);
  5491 
  5492 * infixes may now be declared with names independent of their syntax;
  5493 
  5494 * added typed_print_translation (like print_translation, but may
  5495 access type of constant);
  5496 
  5497 
  5498 *** Classical Reasoner ***
  5499 
  5500 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5501 some limitations.  Blast_tac...
  5502   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5503   + ignores elimination rules that don't have the correct format
  5504         (the conclusion MUST be a formula variable)
  5505   + ignores types, which can make HOL proofs fail
  5506   + rules must not require higher-order unification, e.g. apply_type in ZF
  5507     [message "Function Var's argument not a bound variable" relates to this]
  5508   + its proof strategy is more general but can actually be slower
  5509 
  5510 * substitution with equality assumptions no longer permutes other
  5511 assumptions;
  5512 
  5513 * minor changes in semantics of addafter (now called addaltern); renamed
  5514 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5515 (and access functions for it);
  5516 
  5517 * improved combination of classical reasoner and simplifier:
  5518   + functions for handling clasimpsets
  5519   + improvement of addss: now the simplifier is called _after_ the
  5520     safe steps.
  5521   + safe variant of addss called addSss: uses safe simplifications
  5522     _during_ the safe steps. It is more complete as it allows multiple
  5523     instantiations of unknowns (e.g. with slow_tac).
  5524 
  5525 *** Simplifier ***
  5526 
  5527 * added interface for simplification procedures (functions that
  5528 produce *proven* rewrite rules on the fly, depending on current
  5529 redex);
  5530 
  5531 * ordering on terms as parameter (used for ordered rewriting);
  5532 
  5533 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5534 
  5535 * the solver is now split into a safe and an unsafe part.
  5536 This should be invisible for the normal user, except that the
  5537 functions setsolver and addsolver have been renamed to setSolver and
  5538 addSolver; added safe_asm_full_simp_tac;
  5539 
  5540 
  5541 *** HOL ***
  5542 
  5543 * a generic induction tactic `induct_tac' which works for all datatypes and
  5544 also for type `nat';
  5545 
  5546 * a generic case distinction tactic `exhaust_tac' which works for all
  5547 datatypes and also for type `nat';
  5548 
  5549 * each datatype comes with a function `size';
  5550 
  5551 * patterns in case expressions allow tuple patterns as arguments to
  5552 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5553 
  5554 * primrec now also works with type nat;
  5555 
  5556 * recdef: a new declaration form, allows general recursive functions to be
  5557 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5558 
  5559 * the constant for negation has been renamed from "not" to "Not" to
  5560 harmonize with FOL, ZF, LK, etc.;
  5561 
  5562 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5563 infinite lists;
  5564 
  5565 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5566 
  5567 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  5568 problems in commutative rings, using axiomatic type classes for + and *;
  5569 
  5570 * more examples in HOL/MiniML and HOL/Auth;
  5571 
  5572 * more default rewrite rules for quantifiers, union/intersection;
  5573 
  5574 * a new constant `arbitrary == @x.False';
  5575 
  5576 * HOLCF/IOA replaces old HOL/IOA;
  5577 
  5578 * HOLCF changes: derived all rules and arities
  5579   + axiomatic type classes instead of classes
  5580   + typedef instead of faking type definitions
  5581   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5582   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5583   + eliminated the types void, one, tr
  5584   + use unit lift and bool lift (with translations) instead of one and tr
  5585   + eliminated blift from Lift3.thy (use Def instead of blift)
  5586   all eliminated rules are derived as theorems --> no visible changes ;
  5587 
  5588 
  5589 *** ZF ***
  5590 
  5591 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5592 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5593 as ZF_cs addSIs [equalityI];
  5594 
  5595 
  5596 
  5597 New in Isabelle94-7 (November 96)
  5598 ---------------------------------
  5599 
  5600 * allowing negative levels (as offsets) in prlev and choplev;
  5601 
  5602 * super-linear speedup for large simplifications;
  5603 
  5604 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  5605 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  5606 FAIL); can suppress it using the command Delsimps (ex_simps @
  5607 all_simps); De Morgan laws are also now included, by default;
  5608 
  5609 * improved printing of ==>  :  ~:
  5610 
  5611 * new object-logic "Sequents" adds linear logic, while replacing LK
  5612 and Modal (thanks to Sara Kalvala);
  5613 
  5614 * HOL/Auth: correctness proofs for authentication protocols;
  5615 
  5616 * HOL: new auto_tac combines rewriting and classical reasoning (many
  5617 examples on HOL/Auth);
  5618 
  5619 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  5620 the rewriter and classical reasoner simultaneously;
  5621 
  5622 * function uresult no longer returns theorems in "standard" format;
  5623 regain previous version by: val uresult = standard o uresult;
  5624 
  5625 
  5626 
  5627 New in Isabelle94-6
  5628 -------------------
  5629 
  5630 * oracles -- these establish an interface between Isabelle and trusted
  5631 external reasoners, which may deliver results as theorems;
  5632 
  5633 * proof objects (in particular record all uses of oracles);
  5634 
  5635 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  5636 
  5637 * "constdefs" section in theory files;
  5638 
  5639 * "primrec" section (HOL) no longer requires names;
  5640 
  5641 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  5642 
  5643 
  5644 
  5645 New in Isabelle94-5
  5646 -------------------
  5647 
  5648 * reduced space requirements;
  5649 
  5650 * automatic HTML generation from theories;
  5651 
  5652 * theory files no longer require "..." (quotes) around most types;
  5653 
  5654 * new examples, including two proofs of the Church-Rosser theorem;
  5655 
  5656 * non-curried (1994) version of HOL is no longer distributed;
  5657 
  5658 
  5659 
  5660 New in Isabelle94-4
  5661 -------------------
  5662 
  5663 * greatly reduced space requirements;
  5664 
  5665 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5666 
  5667 * searchable theorem database (see the section "Retrieving theorems" on
  5668 page 8 of the Reference Manual);
  5669 
  5670 * new examples, including Grabczewski's monumental case study of the
  5671 Axiom of Choice;
  5672 
  5673 * The previous version of HOL renamed to Old_HOL;
  5674 
  5675 * The new version of HOL (previously called CHOL) uses a curried syntax
  5676 for functions.  Application looks like f a b instead of f(a,b);
  5677 
  5678 * Mutually recursive inductive definitions finally work in HOL;
  5679 
  5680 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5681 translates to the operator "split";
  5682 
  5683 
  5684 
  5685 New in Isabelle94-3
  5686 -------------------
  5687 
  5688 * new infix operator, addss, allowing the classical reasoner to
  5689 perform simplification at each step of its search.  Example:
  5690         fast_tac (cs addss ss)
  5691 
  5692 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5693 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5694 look like (a,b) instead of <a,b>;
  5695 
  5696 * PLEASE NOTE: CHOL will eventually replace HOL!
  5697 
  5698 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5699 It translates to the operator "split".  A new theory of integers is available;
  5700 
  5701 * In ZF, integer numerals now denote two's-complement binary integers.
  5702 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5703 
  5704 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5705 of the Axiom of Choice;
  5706 
  5707 
  5708 
  5709 New in Isabelle94-2
  5710 -------------------
  5711 
  5712 * Significantly faster resolution;
  5713 
  5714 * the different sections in a .thy file can now be mixed and repeated
  5715 freely;
  5716 
  5717 * Database of theorems for FOL, HOL and ZF.  New
  5718 commands including qed, qed_goal and bind_thm store theorems in the database.
  5719 
  5720 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5721 a given theory (thms_of), or find out what theory a theorem was proved in
  5722 (theory_of_thm);
  5723 
  5724 * Bugs fixed in the inductive definition and datatype packages;
  5725 
  5726 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5727 and HOL_dup_cs obsolete;
  5728 
  5729 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5730 have been removed;
  5731 
  5732 * Simpler definition of function space in ZF;
  5733 
  5734 * new results about cardinal and ordinal arithmetic in ZF;
  5735 
  5736 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5737 types;
  5738 
  5739 :mode=text:wrap=hard:maxLineLen=72:
  5740 
  5741 
  5742 $Id$