NEWS
author wenzelm
Wed Jan 21 23:21:44 2009 +0100 (2009-01-21)
changeset 29606 fedb8be05f24
parent 29398 89813bbf0f3e
child 29608 564ea783ace8
permissions -rw-r--r--
removed Ids;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Simplified main Isabelle executables, with less surprises on
    10 case-insensitive file-systems (such as Mac OS).
    11 
    12   - The main Isabelle tool wrapper is now called "isabelle" instead of
    13     "isatool."
    14 
    15   - The former "isabelle" alias for "isabelle-process" has been
    16     removed (should rarely occur to regular users).
    17 
    18   - The former "isabelle-interface" and its alias "Isabelle" have been
    19     removed (interfaces are now regular Isabelle tools).
    20 
    21 Within scripts and make files, the Isabelle environment variables
    22 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
    23 respectively.  (The latter are still available as legacy feature.)
    24 
    25 The old isabelle-interface wrapper could react in confusing ways if
    26 the interface was uninstalled or changed otherwise.  Individual
    27 interface tool configuration is now more explicit, see also the
    28 Isabelle system manual.  In particular, Proof General is now available
    29 via "isabelle emacs".
    30 
    31 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
    32 purge installed copies of Isabelle executables and re-run "isabelle
    33 install -p ...", or use symlinks.
    34 
    35 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
    36 old ~/isabelle, which was slightly non-standard and apt cause
    37 surprises on case-insensitive file-systems.
    38 
    39 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
    40 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
    41 care is required when using older releases of Isabelle.  Note that
    42 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
    43 Isabelle distribution.
    44 
    45 * Proofs of fully specified statements are run in parallel on
    46 multi-core systems.  A speedup factor of 2-3 can be expected on a
    47 regular 4-core machine, if the initial heap space is made reasonably
    48 large (cf. Poly/ML option -H).  [Poly/ML 5.2.1 or later]
    49 
    50 * The Isabelle System Manual (system) has been updated, with formally
    51 checked references as hyperlinks.
    52 
    53 * Generalized Isar history, with support for linear undo, direct state
    54 addressing etc.
    55 
    56 * Recovered hiding of consts, which was accidentally broken in
    57 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
    58 makes c inaccessible; consider using ``hide (open) const c'' instead.
    59 
    60 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
    61 interface instead.
    62 
    63 * There is a new syntactic category "float_const" for signed decimal
    64 fractions (e.g. 123.45 or -123.45).
    65 
    66 
    67 *** Pure ***
    68 
    69 * Type Binding.T gradually replaces formerly used type bstring for names
    70 to be bound.  Name space interface for declarations has been simplified:
    71 
    72   NameSpace.declare: NameSpace.naming
    73     -> Binding.T -> NameSpace.T -> string * NameSpace.T
    74   NameSpace.bind: NameSpace.naming
    75     -> Binding.T * 'a -> 'a NameSpace.table -> string * 'a NameSpace.table
    76          (*exception Symtab.DUP*)
    77 
    78 See further modules src/Pure/General/binding.ML and
    79 src/Pure/General/name_space.ML
    80 
    81 * Module moves in repository:
    82     src/Pure/Tools/value.ML ~> src/Tools/
    83     src/Pure/Tools/quickcheck.ML ~> src/Tools/
    84 
    85 * Slightly more coherent Pure syntax, with updated documentation in
    86 isar-ref manual.  Removed locales meta_term_syntax and
    87 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
    88 INCOMPATIBILITY in rare situations.
    89 
    90 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
    91 hypotheses.  Sorts required in the course of reasoning need to be
    92 covered by the constraints in the initial statement, completed by the
    93 type instance information of the background theory.  Non-trivial sort
    94 hypotheses, which rarely occur in practice, may be specified via
    95 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
    96 
    97   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
    98 
    99 The result contains an implicit sort hypotheses as before --
   100 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   101 normalization.
   102 
   103 * Changed defaults for unify configuration options:
   104 
   105   unify_trace_bound = 50 (formerly 25)
   106   unify_search_bound = 60 (formerly 30)
   107 
   108 * Different bookkeeping for code equations:
   109   a) On theory merge, the last set of code equations for a particular constant
   110      is taken (in accordance with the policy applied by other parts of the
   111      code generator framework).
   112   b) Code equations stemming from explicit declarations (e.g. code attribute)
   113      gain priority over default code equations stemming from definition, primrec,
   114      fun etc.
   115   INCOMPATIBILITY.
   116 
   117 * Global versions of theorems stemming from classes do not carry
   118 a parameter prefix any longer.  INCOMPATIBILITY.
   119 
   120 * Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   121 In existing theorem specifications replace the includes element by the
   122 respective context elements of the included locale, omitting those that
   123 are already present in the theorem specification.  Multiple assume
   124 elements of a locale should be replaced by a single one involving the
   125 locale predicate.  In the proof body, declarations (most notably
   126 theorems) may be regained by interpreting the respective locales in the
   127 proof context as required (command "interpret").
   128 If using "includes" in replacement of a target solely because the
   129 parameter types in the theorem are not as general as in the target,
   130 consider declaring a new locale with additional type constraints on the
   131 parameters (context element "constrains").
   132 
   133 * Dropped "locale (open)".  INCOMPATIBILITY.
   134 
   135 * Interpretation commands no longer attempt to simplify goal.
   136 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   137 methods intro_locales and unfold_locales to clarify.
   138 
   139 * Interpretation commands no longer accept interpretation attributes.
   140 INCOMPATBILITY.
   141 
   142 * Complete re-implementation of locales.  INCOMPATIBILITY.
   143 The most important changes are listed below.  See documentation
   144 (forthcoming) and tutorial (also forthcoming) for details.
   145 
   146 - In locale expressions, instantiation replaces renaming.  Parameters
   147 must be declared in a for clause.  To aid compatibility with previous
   148 parameter inheritance, in locale declarations, parameters that are not
   149 'touched' (instantiation position "_" or omitted) are implicitly added
   150 with their syntax at the beginning of the for clause.
   151 
   152 - Syntax from abbreviations and definitions in locales is available in
   153 locale expressions and context elements.  The latter is particularly
   154 useful in locale declarations.
   155 
   156 - More flexible mechanisms to qualify names generated by locale
   157 expressions.  Qualifiers (prefixes) may be specified in locale
   158 expressions.  Available are normal qualifiers (syntax "name:") and strict
   159 qualifiers (syntax "name!:").  The latter must occur in name references
   160 and are useful to avoid accidental hiding of names, the former are
   161 optional.  Qualifiers derived from the parameter names of a locale are no
   162 longer generated.
   163 
   164 - "sublocale l < e" replaces "interpretation l < e".  The instantiation
   165 clause in "interpretation" and "interpret" (square brackets) is no
   166 longer available.  Use locale expressions.
   167 
   168 - When converting proof scripts, be sure to replace qualifiers in
   169 "interpretation" and "interpret" by strict qualifiers.  Qualifiers in
   170 locale expressions range over a single locale instance only.
   171 
   172 * Command 'instance': attached definitions no longer accepted.
   173 INCOMPATIBILITY, use proper 'instantiation' target.
   174 
   175 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   176 
   177 * The 'axiomatization' command now only works within a global theory
   178 context.  INCOMPATIBILITY.
   179 
   180 
   181 *** Document preparation ***
   182 
   183 * Antiquotation @{lemma} now imitates a regular terminal proof,
   184 demanding keyword 'by' and supporting the full method expression
   185 syntax just like the Isar command 'by'.
   186 
   187 
   188 *** HOL ***
   189 
   190 * Made source layout more coherent with logical distribution
   191 structure:
   192 
   193     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   194     src/HOL/Library/Code_Message.thy ~> src/HOL/
   195     src/HOL/Library/Dense_Linear_Order.thy ~> src/HOL/
   196     src/HOL/Library/GCD.thy ~> src/HOL/
   197     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   198     src/HOL/Library/Parity.thy ~> src/HOL/
   199     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   200     src/HOL/Real/ContNotDenum.thy ~> src/HOL/
   201     src/HOL/Real/Lubs.thy ~> src/HOL/
   202     src/HOL/Real/PReal.thy ~> src/HOL/
   203     src/HOL/Real/Rational.thy ~> src/HOL/
   204     src/HOL/Real/RComplete.thy ~> src/HOL/
   205     src/HOL/Real/RealDef.thy ~> src/HOL/
   206     src/HOL/Real/RealPow.thy ~> src/HOL/
   207     src/HOL/Real/Real.thy ~> src/HOL/
   208     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   209     src/HOL/Complex/Complex.thy ~> src/HOL/
   210     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/
   211     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/
   212     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   213     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   214     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   215     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   216     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   217     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   218     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   219     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   220     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   221     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   222     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   223     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   224     src/HOL/Real/Float ~> src/HOL/Library/
   225     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   226     src/HOL/Real/RealVector.thy ~> src/HOL/
   227 
   228     src/HOL/arith_data.ML ~> src/HOL/Tools
   229     src/HOL/hologic.ML ~> src/HOL/Tools
   230     src/HOL/simpdata.ML ~> src/HOL/Tools
   231     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   232     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   233     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   234     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   235     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   236     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   237     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   238 
   239     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   240     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   241     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   242     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   243     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   244     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   245 
   246 * If methods "eval" and "evaluation" encounter a structured proof state
   247 with !!/==>, only the conclusion is evaluated to True (if possible),
   248 avoiding strange error messages.
   249 
   250 * Simplifier: simproc for let expressions now unfolds if bound variable
   251 occurs at most one time in let expression body.  INCOMPATIBILITY.
   252 
   253 * New classes "top" and "bot" with corresponding operations "top" and "bot"
   254 in theory Orderings;  instantiation of class "complete_lattice" requires
   255 instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   256 
   257 * Changed definition lemma "less_fun_def" in order to provide an instance
   258 for preorders on functions;  use lemma "less_le" instead.  INCOMPATIBILITY.
   259 
   260 * Unified theorem tables for both code code generators.  Thus
   261 [code func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   262 
   263 * Constants "undefined" and "default" replace "arbitrary".  Usually
   264 "undefined" is the right choice to replace "arbitrary", though logically
   265 there is no difference.  INCOMPATIBILITY.
   266 
   267 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   268 Posix processes.  Avoids potentially expensive forking of the ML
   269 process.  New thread-based implementation also works on non-Unix
   270 platforms (Cygwin).  Provers are no longer hardwired, but defined
   271 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   272 commands are covered in the isar-ref manual
   273 
   274 * Wrapper scripts for remote SystemOnTPTP service allows to use
   275 sledgehammer without local ATP installation (Vampire etc.).  See also
   276 ISABELLE_HOME/contrib/SystemOnTPTP and the VAMPIRE_HOME setting
   277 variable.  Other provers may be included via suitable ML wrappers, see
   278 also src/HOL/ATP_Linkup.thy.
   279 
   280 * Normalization by evaluation now allows non-leftlinear equations.
   281 Declare with attribute [code nbe].
   282 
   283 * Command "value" now integrates different evaluation
   284 mechanisms.  The result of the first successful evaluation mechanism
   285 is printed.  In square brackets a particular named evaluation
   286 mechanisms may be specified (currently, [SML], [code] or [nbe]).  See
   287 further src/HOL/ex/Eval_Examples.thy.
   288 
   289 * New method "sizechange" to automate termination proofs using (a
   290 modification of) the size-change principle. Requires SAT solver. See
   291 src/HOL/ex/Termination.thy for examples.
   292 
   293 * HOL/Orderings: class "wellorder" moved here, with explicit induction
   294 rule "less_induct" as assumption.  For instantiation of "wellorder" by
   295 means of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.
   296 
   297 * HOL/Orderings: added class "preorder" as superclass of "order".
   298 INCOMPATIBILITY: Instantiation proofs for order, linorder
   299 etc. slightly changed.  Some theorems named order_class.* now named
   300 preorder_class.*.
   301 
   302 * HOL/Finite_Set: added a new fold combinator of type
   303   ('a => 'b => 'b) => 'b => 'a set => 'b
   304 Occasionally this is more convenient than the old fold combinator which is
   305 now defined in terms of the new one and renamed to fold_image.
   306 
   307 * HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
   308 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   309 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   310 of lemmas from Divides has been generalized from nat to class
   311 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   312 renames resulting from duplicate elimination:
   313 
   314     dvd_def_mod ~>          dvd_eq_mod_eq_0
   315     zero_dvd_iff ~>         dvd_0_left_iff
   316     dvd_0 ~>                dvd_0_right
   317     DIVISION_BY_ZERO_DIV ~> div_by_0
   318     DIVISION_BY_ZERO_MOD ~> mod_by_0
   319     mult_div ~>             div_mult_self2_is_id
   320     mult_mod ~>             mod_mult_self2_is_0
   321 
   322 * HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   323 zlcm (for int); carried together from various gcd/lcm developements in
   324 the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
   325 corresponding theorems renamed accordingly.  INCOMPATIBILY.  To
   326 recover tupled syntax, use syntax declarations like:
   327 
   328     hide (open) const gcd
   329     abbreviation gcd where
   330       "gcd == (%(a, b). GCD.gcd a b)"
   331     notation (output)
   332       GCD.gcd ("gcd '(_, _')")
   333 
   334 (analogously for lcm, zgcd, zlcm).
   335 
   336 * HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   337 
   338 * The real numbers offer decimal input syntax: 12.34 is translated into
   339   1234/10^4. This translation is not reversed upon output.
   340 
   341 * New ML antiquotation @{code}: takes constant as argument, generates
   342 corresponding code in background and inserts name of the corresponding
   343 resulting ML value/function/datatype constructor binding in place.
   344 All occurrences of @{code} with a single ML block are generated
   345 simultaneously.  Provides a generic and safe interface for
   346 instrumentalizing code generation.  See HOL/ex/Code_Antiq for a toy
   347 example, or HOL/Complex/ex/ReflectedFerrack for a more ambitious
   348 application.  In future you ought refrain from ad-hoc compiling
   349 generated SML code on the ML toplevel.  Note that (for technical
   350 reasons) @{code} cannot refer to constants for which user-defined
   351 serializations are set.  Refer to the corresponding ML counterpart
   352 directly in that cases.
   353 
   354 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   355 Complex_Main.thy remain as they are.
   356 
   357 * New image HOL-Plain provides a minimal HOL with the most important
   358 tools available (inductive, datatype, primrec, ...).  By convention
   359 the corresponding theory Plain should be ancestor of every further
   360 (library) theory.  Some library theories now have ancestor Plain
   361 (instead of Main), thus theory Main occasionally has to be imported
   362 explicitly.
   363 
   364 * The metis method now fails in the usual manner, rather than raising
   365 an exception, if it determines that it cannot prove the theorem.
   366 
   367 * The metis method no longer fails because the theorem is too trivial
   368 (contains the empty clause).
   369 
   370 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   371 as the structured Isar versions "cases" and "induct", cf. the
   372 corresponding "cases" and "induct" attributes.  Mutual induction rules
   373 are now presented as a list of individual projections
   374 (e.g. foo_bar.inducts for types foo and bar); the old format with
   375 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   376 rare situations a different rule is selected --- notably nested tuple
   377 elimination instead of former prod.exhaust: use explicit (case_tac t
   378 rule: prod.exhaust) here.
   379 
   380 * Attributes "cases", "induct", "coinduct" support "del" option.
   381 
   382 * Removed fact "case_split_thm", which duplicates "case_split".
   383 
   384 * Command 'rep_datatype': instead of theorem names the command now
   385 takes a list of terms denoting the constructors of the type to be
   386 represented as datatype.  The characteristic theorems have to be
   387 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   388 have disappeared in favour of existing ones:
   389 
   390     unit_induct                 ~> unit.induct
   391     prod_induct                 ~> prod.induct
   392     sum_induct                  ~> sum.induct
   393     Suc_Suc_eq                  ~> nat.inject
   394     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   395 
   396 * Library/Nat_Infinity: added addition, numeral syntax and more
   397 instantiations for algebraic structures.  Removed some duplicate
   398 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   399 
   400 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   401 menu.
   402 
   403 
   404 *** HOL-Algebra ***
   405 
   406 * New locales for orders and lattices where the equivalence relation
   407   is not restricted to equality.  INCOMPATIBILITY: all order and
   408   lattice locales use a record structure with field eq for the
   409   equivalence.
   410 
   411 * New theory of factorial domains.
   412 
   413 * Units_l_inv and Units_r_inv are now simprules by default.
   414 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   415 and/or r_inv will now also require deletion of these lemmas.
   416 
   417 * Renamed the following theorems.  INCOMPATIBILITY.
   418 UpperD ~> Upper_memD
   419 LowerD ~> Lower_memD
   420 least_carrier ~> least_closed
   421 greatest_carrier ~> greatest_closed
   422 greatest_Lower_above ~> greatest_Lower_below
   423 one_zero ~> carrier_one_zero
   424 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   425 
   426 
   427 *** HOL-NSA ***
   428 
   429 * Created new image HOL-NSA, containing theories of nonstandard
   430 analysis which were previously part of HOL-Complex.  Entry point
   431 Hyperreal.thy remains valid, but theories formerly using
   432 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   433 
   434 
   435 *** ZF ***
   436 
   437 * Proof of Zorn's Lemma for partial orders.
   438 
   439 
   440 *** ML ***
   441 
   442 * High-level support for concurrent ML programming, see
   443 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   444 particularly convenient to organize independent functional
   445 computations.  The concept of "synchronized variables" provides a
   446 higher-order interface for components with shared state, avoiding the
   447 delicate details of mutexes and condition variables.  [Poly/ML 5.2.1
   448 or later]
   449 
   450 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   451 to 'a -> thm, while results are always tagged with an authentic oracle
   452 name.  The Isar command 'oracle' is now polymorphic, no argument type
   453 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   454 accordingly.  Note that extra performance may be gained by producing
   455 the cterm carefully, avoiding slow Thm.cterm_of.
   456 
   457 * ML bindings produced via Isar commands are stored within the Isar
   458 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   459 become thread-safe and work with undo as expected (concerning
   460 top-level bindings, not side-effects on global references).
   461 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   462 compiler at runtime; really global bindings need to be given outside a
   463 theory. [Poly/ML 5.2 or later]
   464 
   465 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   466 context. Top-level ML bindings are stored within the proof context in
   467 a purely sequential fashion, disregarding the nested proof structure.
   468 ML bindings introduced by 'ML_prf' are discarded at the end of the
   469 proof.  [Poly/ML 5.2 or later]
   470 
   471 * Generic Toplevel.add_hook interface allows to analyze the result of
   472 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   473 for theorem dependency output of transactions resulting in a new
   474 theory state.
   475 
   476 * Name bindings in higher specification mechanisms (notably
   477 LocalTheory.define, LocalTheory.note, and derived packages) are now
   478 formalized as type Name.binding, replacing old bstring.
   479 INCOMPATIBILITY, need to wrap strings via Name.binding function, see
   480 also Name.name_of.  Packages should pass name bindings given by the
   481 user to underlying specification mechanisms; this enables precise
   482 tracking of source positions, for example.
   483 
   484 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   485 LocalTheory.note etc.) now refer to the *full* internal name, not the
   486 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   487 
   488 * Rules and tactics that read instantiations (read_instantiate,
   489 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   490 context, which is required for parsing and type-checking.  Moreover,
   491 the variables are specified as plain indexnames, not string encodings
   492 thereof.  INCOMPATIBILITY.
   493 
   494 * Disposed old type and term read functions (Sign.read_def_typ,
   495 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   496 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   497 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   498 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   499 resort for legacy applications.
   500 
   501 * Antiquotations: block-structured compilation context indicated by
   502 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   503 
   504   @{let ?pat = term}                      - term abbreviation (HO matching)
   505   @{note name = fact}                     - fact abbreviation
   506   @{thm fact}                             - singleton fact (with attributes)
   507   @{thms fact}                            - general fact (with attributes)
   508   @{lemma prop by method}                 - singleton goal
   509   @{lemma prop by meth1 meth2}            - singleton goal
   510   @{lemma prop1 ... propN by method}      - general goal
   511   @{lemma prop1 ... propN by meth1 meth2} - general goal
   512   @{lemma (open) ...}                     - open derivation
   513 
   514 
   515 *** System ***
   516 
   517 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   518 Poly/ML 5.2.1 or later.
   519 
   520 * The Isabelle "emacs" tool provides a specific interface to invoke
   521 Proof General / Emacs, with more explicit failure if that is not
   522 installed (the old isabelle-interface script silently falls back on
   523 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   524 installation location of the Proof General distribution.
   525 
   526 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   527 the Isabelle process into a JVM/Scala application.  See
   528 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   529 process wrapper has been discontinued.)
   530 
   531 * Status messages (with exact source position information) are
   532 emitted, if proper markup print mode is enabled.  This allows
   533 user-interface components to provide detailed feedback on internal
   534 prover operations.
   535 
   536 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   537 
   538 
   539 
   540 New in Isabelle2008 (June 2008)
   541 -------------------------------
   542 
   543 *** General ***
   544 
   545 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   546 and updated, with formally checked references as hyperlinks.
   547 
   548 * Theory loader: use_thy (and similar operations) no longer set the
   549 implicit ML context, which was occasionally hard to predict and in
   550 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   551 provides a proper context already.
   552 
   553 * Theory loader: old-style ML proof scripts being *attached* to a thy
   554 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   555 'use' within a theory file will do the job.
   556 
   557 * Name space merge now observes canonical order, i.e. the second space
   558 is inserted into the first one, while existing entries in the first
   559 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   560 swap theory imports.
   561 
   562 * Syntax: symbol \<chi> is now considered a letter.  Potential
   563 INCOMPATIBILITY in identifier syntax etc.
   564 
   565 * Outer syntax: string tokens no longer admit escaped white space,
   566 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   567 white space without escapes.
   568 
   569 * Outer syntax: string tokens may contain arbitrary character codes
   570 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   571 "foo_bar".
   572 
   573 
   574 *** Pure ***
   575 
   576 * Context-dependent token translations.  Default setup reverts locally
   577 fixed variables, and adds hilite markup for undeclared frees.
   578 
   579 * Unused theorems can be found using the new command 'unused_thms'.
   580 There are three ways of invoking it:
   581 
   582 (1) unused_thms
   583      Only finds unused theorems in the current theory.
   584 
   585 (2) unused_thms thy_1 ... thy_n -
   586      Finds unused theorems in the current theory and all of its ancestors,
   587      excluding the theories thy_1 ... thy_n and all of their ancestors.
   588 
   589 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   590      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   591      their ancestors, excluding the theories thy_1 ... thy_n and all of
   592      their ancestors.
   593 
   594 In order to increase the readability of the list produced by
   595 unused_thms, theorems that have been created by a particular instance
   596 of a theory command such as 'inductive' or 'function' are considered
   597 to belong to the same "group", meaning that if at least one theorem in
   598 this group is used, the other theorems in the same group are no longer
   599 reported as unused.  Moreover, if all theorems in the group are
   600 unused, only one theorem in the group is displayed.
   601 
   602 Note that proof objects have to be switched on in order for
   603 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   604 usually the case when using Proof General with the default settings).
   605 
   606 * Authentic naming of facts disallows ad-hoc overwriting of previous
   607 theorems within the same name space.  INCOMPATIBILITY, need to remove
   608 duplicate fact bindings, or even accidental fact duplications.  Note
   609 that tools may maintain dynamically scoped facts systematically, using
   610 PureThy.add_thms_dynamic.
   611 
   612 * Command 'hide' now allows to hide from "fact" name space as well.
   613 
   614 * Eliminated destructive theorem database, simpset, claset, and
   615 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   616 update of theories within ML code.
   617 
   618 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   619 INCOMPATIBILITY, object-logics depending on former Pure require
   620 additional setup PureThy.old_appl_syntax_setup; object-logics
   621 depending on former CPure need to refer to Pure.
   622 
   623 * Commands 'use' and 'ML' are now purely functional, operating on
   624 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   625 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   626 INCOMPATIBILITY.
   627 
   628 * Command 'setup': discontinued implicit version with ML reference.
   629 
   630 * Instantiation target allows for simultaneous specification of class
   631 instance operations together with an instantiation proof.
   632 Type-checking phase allows to refer to class operations uniformly.
   633 See src/HOL/Complex/Complex.thy for an Isar example and
   634 src/HOL/Library/Eval.thy for an ML example.
   635 
   636 * Indexing of literal facts: be more serious about including only
   637 facts from the visible specification/proof context, but not the
   638 background context (locale etc.).  Affects `prop` notation and method
   639 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   640 situations.
   641 
   642 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   643 "(open)" option, which used to expose internal bound variables to the
   644 proof text.
   645 
   646 * Isar statements: removed obsolete case "rule_context".
   647 INCOMPATIBILITY, better use explicit fixes/assumes.
   648 
   649 * Locale proofs: default proof step now includes 'unfold_locales';
   650 hence 'proof' without argument may be used to unfold locale
   651 predicates.
   652 
   653 
   654 *** Document preparation ***
   655 
   656 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   657 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   658 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   659 spot); renamed link color from "darkblue" to "linkcolor" (default
   660 value unchanged, can be redefined via \definecolor); no longer sets
   661 "a4paper" option (unnecessary or even intrusive).
   662 
   663 * Antiquotation @{lemma A method} proves proposition A by the given
   664 method (either a method name or a method name plus (optional) method
   665 arguments in parentheses) and prints A just like @{prop A}.
   666 
   667 
   668 *** HOL ***
   669 
   670 * New primrec package.  Specification syntax conforms in style to
   671 definition/function/....  No separate induction rule is provided.  The
   672 "primrec" command distinguishes old-style and new-style specifications
   673 by syntax.  The former primrec package is now named OldPrimrecPackage.
   674 When adjusting theories, beware: constants stemming from new-style
   675 primrec specifications have authentic syntax.
   676 
   677 * Metis prover is now an order of magnitude faster, and also works
   678 with multithreading.
   679 
   680 * Metis: the maximum number of clauses that can be produced from a
   681 theorem is now given by the attribute max_clauses.  Theorems that
   682 exceed this number are ignored, with a warning printed.
   683 
   684 * Sledgehammer no longer produces structured proofs by default. To
   685 enable, declare [[sledgehammer_full = true]].  Attributes
   686 reconstruction_modulus, reconstruction_sorts renamed
   687 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   688 
   689 * Method "induct_scheme" derives user-specified induction rules
   690 from well-founded induction and completeness of patterns. This factors
   691 out some operations that are done internally by the function package
   692 and makes them available separately.  See
   693 src/HOL/ex/Induction_Scheme.thy for examples.
   694 
   695 * More flexible generation of measure functions for termination
   696 proofs: Measure functions can be declared by proving a rule of the
   697 form "is_measure f" and giving it the [measure_function] attribute.
   698 The "is_measure" predicate is logically meaningless (always true), and
   699 just guides the heuristic.  To find suitable measure functions, the
   700 termination prover sets up the goal "is_measure ?f" of the appropriate
   701 type and generates all solutions by prolog-style backwards proof using
   702 the declared rules.
   703 
   704 This setup also deals with rules like 
   705 
   706   "is_measure f ==> is_measure (list_size f)"
   707 
   708 which accommodates nested datatypes that recurse through lists.
   709 Similar rules are predeclared for products and option types.
   710 
   711 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   712 
   713   INCOMPATIBILITIES:
   714 
   715   - Definitions of overloaded constants on sets have to be replaced by
   716     definitions on => and bool.
   717 
   718   - Some definitions of overloaded operators on sets can now be proved
   719     using the definitions of the operators on => and bool.  Therefore,
   720     the following theorems have been renamed:
   721 
   722       subset_def   -> subset_eq
   723       psubset_def  -> psubset_eq
   724       set_diff_def -> set_diff_eq
   725       Compl_def    -> Compl_eq
   726       Sup_set_def  -> Sup_set_eq
   727       Inf_set_def  -> Inf_set_eq
   728       sup_set_def  -> sup_set_eq
   729       inf_set_def  -> inf_set_eq
   730 
   731   - Due to the incompleteness of the HO unification algorithm, some
   732     rules such as subst may require manual instantiation, if some of
   733     the unknowns in the rule is a set.
   734 
   735   - Higher order unification and forward proofs:
   736     The proof pattern
   737 
   738       have "P (S::'a set)" <...>
   739       then have "EX S. P S" ..
   740 
   741     no longer works (due to the incompleteness of the HO unification
   742     algorithm) and must be replaced by the pattern
   743 
   744       have "EX S. P S"
   745       proof
   746         show "P S" <...>
   747       qed
   748 
   749   - Calculational reasoning with subst (or similar rules):
   750     The proof pattern
   751 
   752       have "P (S::'a set)" <...>
   753       also have "S = T" <...>
   754       finally have "P T" .
   755 
   756     no longer works (for similar reasons as the previous example) and
   757     must be replaced by something like
   758 
   759       have "P (S::'a set)" <...>
   760       moreover have "S = T" <...>
   761       ultimately have "P T" by simp
   762 
   763   - Tactics or packages written in ML code:
   764     Code performing pattern matching on types via
   765 
   766       Type ("set", [T]) => ...
   767 
   768     must be rewritten. Moreover, functions like strip_type or
   769     binder_types no longer return the right value when applied to a
   770     type of the form
   771 
   772       T1 => ... => Tn => U => bool
   773 
   774     rather than
   775 
   776       T1 => ... => Tn => U set
   777 
   778 * Merged theories Wellfounded_Recursion, Accessible_Part and
   779 Wellfounded_Relations to theory Wellfounded.
   780 
   781 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   782 
   783 * Class finite no longer treats UNIV as class parameter.  Use class
   784 enum from theory Library/Enum instead to achieve a similar effect.
   785 INCOMPATIBILITY.
   786 
   787 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   788 and "Cons".  INCOMPATIBILITY.
   789 
   790 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   791 Potential INCOMPATIBILITY.
   792 
   793 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   794 injective_fst_snd removed, use split_eta and prod_eqI instead.
   795 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   796 
   797 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   798 the same name in theory Orderings:
   799 
   800   less_trans
   801   less_linear
   802   le_imp_less_or_eq
   803   le_less_trans
   804   less_le_trans
   805   less_not_sym
   806   less_asym
   807 
   808 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
   809 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
   810 and different variable names.
   811 
   812 * Library/Option_ord.thy: Canonical order on option type.
   813 
   814 * Library/RBT.thy: Red-black trees, an efficient implementation of
   815 finite maps.
   816 
   817 * Library/Countable.thy: Type class for countable types.
   818 
   819 * Theory Int: The representation of numerals has changed.  The infix
   820 operator BIT and the bit datatype with constructors B0 and B1 have
   821 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
   822 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
   823 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
   824 accordingly.
   825 
   826 * Theory Nat: definition of <= and < on natural numbers no longer
   827 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
   828 le_def and less_def have disappeared.  Consider lemmas not_less
   829 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
   830 
   831 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
   832 (whose purpose mainly is for various fold_set functionals) have been
   833 abandoned in favor of the existing algebraic classes
   834 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
   835 lower_semilattice (resp. upper_semilattice) and linorder.
   836 INCOMPATIBILITY.
   837 
   838 * Theory Transitive_Closure: induct and cases rules now declare proper
   839 case_names ("base" and "step").  INCOMPATIBILITY.
   840 
   841 * Theorem Inductive.lfp_ordinal_induct generalized to complete
   842 lattices.  The form set-specific version is available as
   843 Inductive.lfp_ordinal_induct_set.
   844 
   845 * Renamed theorems "power.simps" to "power_int.simps".
   846 INCOMPATIBILITY.
   847 
   848 * Class semiring_div provides basic abstract properties of semirings
   849 with division and modulo operations.  Subsumes former class dvd_mod.
   850 
   851 * Merged theories IntDef, Numeral and IntArith into unified theory
   852 Int.  INCOMPATIBILITY.
   853 
   854 * Theory Library/Code_Index: type "index" now represents natural
   855 numbers rather than integers.  INCOMPATIBILITY.
   856 
   857 * New class "uminus" with operation "uminus" (split of from class
   858 "minus" which now only has operation "minus", binary).
   859 INCOMPATIBILITY.
   860 
   861 * Constants "card", "internal_split", "option_map" now with authentic
   862 syntax.  INCOMPATIBILITY.
   863 
   864 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
   865 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
   866 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
   867 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
   868 Sup_set_def, le_def, less_def, option_map_def now with object
   869 equality.  INCOMPATIBILITY.
   870 
   871 * Records. Removed K_record, and replaced it by pure lambda term
   872 %x. c. The simplifier setup is now more robust against eta expansion.
   873 INCOMPATIBILITY: in cases explicitly referring to K_record.
   874 
   875 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
   876 
   877 * Library/ListVector: new theory of arithmetic vector operations.
   878 
   879 * Library/Order_Relation: new theory of various orderings as sets of
   880 pairs.  Defines preorders, partial orders, linear orders and
   881 well-orders on sets and on types.
   882 
   883 
   884 *** ZF ***
   885 
   886 * Renamed some theories to allow to loading both ZF and HOL in the
   887 same session:
   888 
   889   Datatype  -> Datatype_ZF
   890   Inductive -> Inductive_ZF
   891   Int       -> Int_ZF
   892   IntDiv    -> IntDiv_ZF
   893   Nat       -> Nat_ZF
   894   List      -> List_ZF
   895   Main      -> Main_ZF
   896 
   897 INCOMPATIBILITY: ZF theories that import individual theories below
   898 Main might need to be adapted.  Regular theory Main is still
   899 available, as trivial extension of Main_ZF.
   900 
   901 
   902 *** ML ***
   903 
   904 * ML within Isar: antiquotation @{const name} or @{const
   905 name(typargs)} produces statically-checked Const term.
   906 
   907 * Functor NamedThmsFun: data is available to the user as dynamic fact
   908 (of the same name).  Removed obsolete print command.
   909 
   910 * Removed obsolete "use_legacy_bindings" function.
   911 
   912 * The ``print mode'' is now a thread-local value derived from a global
   913 template (the former print_mode reference), thus access becomes
   914 non-critical.  The global print_mode reference is for session
   915 management only; user-code should use print_mode_value,
   916 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
   917 
   918 * Functions system/system_out provide a robust way to invoke external
   919 shell commands, with propagation of interrupts (requires Poly/ML
   920 5.2.1).  Do not use OS.Process.system etc. from the basis library!
   921 
   922 
   923 *** System ***
   924 
   925 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
   926 in accordance with Proof General 3.7, which prefers GNU emacs.
   927 
   928 * isatool tty runs Isabelle process with plain tty interaction;
   929 optional line editor may be specified via ISABELLE_LINE_EDITOR
   930 setting, the default settings attempt to locate "ledit" and "rlwrap".
   931 
   932 * isatool browser now works with Cygwin as well, using general
   933 "javapath" function defined in Isabelle process environment.
   934 
   935 * YXML notation provides a simple and efficient alternative to
   936 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
   937 isatool yxml as described in the Isabelle system manual.
   938 
   939 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
   940 provides general wrapper for managing an Isabelle process in a robust
   941 fashion, with ``cooked'' output from stdin/stderr.
   942 
   943 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
   944 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
   945 
   946 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
   947 way of changing the user's settings is via
   948 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
   949 script.
   950 
   951 * Multithreading.max_threads := 0 refers to the number of actual CPU
   952 cores of the underlying machine, which is a good starting point for
   953 optimal performance tuning.  The corresponding usedir option -M allows
   954 "max" as an alias for "0".  WARNING: does not work on certain versions
   955 of Mac OS (with Poly/ML 5.1).
   956 
   957 * isabelle-process: non-ML sessions are run with "nice", to reduce the
   958 adverse effect of Isabelle flooding interactive front-ends (notably
   959 ProofGeneral / XEmacs).
   960 
   961 
   962 
   963 New in Isabelle2007 (November 2007)
   964 -----------------------------------
   965 
   966 *** General ***
   967 
   968 * More uniform information about legacy features, notably a
   969 warning/error of "Legacy feature: ...", depending on the state of the
   970 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
   971 legacy features will disappear eventually.
   972 
   973 * Theory syntax: the header format ``theory A = B + C:'' has been
   974 discontinued in favour of ``theory A imports B C begin''.  Use isatool
   975 fixheaders to convert existing theory files.  INCOMPATIBILITY.
   976 
   977 * Theory syntax: the old non-Isar theory file format has been
   978 discontinued altogether.  Note that ML proof scripts may still be used
   979 with Isar theories; migration is usually quite simple with the ML
   980 function use_legacy_bindings.  INCOMPATIBILITY.
   981 
   982 * Theory syntax: some popular names (e.g. 'class', 'declaration',
   983 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
   984 quotes.
   985 
   986 * Theory loader: be more serious about observing the static theory
   987 header specifications (including optional directories), but not the
   988 accidental file locations of previously successful loads.  The strict
   989 update policy of former update_thy is now already performed by
   990 use_thy, so the former has been removed; use_thys updates several
   991 theories simultaneously, just as 'imports' within a theory header
   992 specification, but without merging the results.  Potential
   993 INCOMPATIBILITY: may need to refine theory headers and commands
   994 ROOT.ML which depend on load order.
   995 
   996 * Theory loader: optional support for content-based file
   997 identification, instead of the traditional scheme of full physical
   998 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
   999 (cf. the system manual).  The new scheme allows to work with
  1000 non-finished theories in persistent session images, such that source
  1001 files may be moved later on without requiring reloads.
  1002 
  1003 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1004 file (with the same base name as the theory) are considered a legacy
  1005 feature, which will disappear eventually. Even now, the theory loader
  1006 no longer maintains dependencies on such files.
  1007 
  1008 * Syntax: the scope for resolving ambiguities via type-inference is
  1009 now limited to individual terms, instead of whole simultaneous
  1010 specifications as before. This greatly reduces the complexity of the
  1011 syntax module and improves flexibility by separating parsing and
  1012 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1013 'fixes' etc.) are required in rare situations.
  1014 
  1015 * Syntax: constants introduced by new-style packages ('definition',
  1016 'abbreviation' etc.) are passed through the syntax module in
  1017 ``authentic mode''. This means that associated mixfix annotations
  1018 really stick to such constants, independently of potential name space
  1019 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1020 trees are represented slightly differently, may need to adapt syntax
  1021 translations accordingly. Use CONST marker in 'translations' and
  1022 @{const_syntax} antiquotation in 'parse_translation' etc.
  1023 
  1024 * Legacy goal package: reduced interface to the bare minimum required
  1025 to keep existing proof scripts running.  Most other user-level
  1026 functions are now part of the OldGoals structure, which is *not* open
  1027 by default (consider isatool expandshort before open OldGoals).
  1028 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1029 these tend to cause confusion about the actual goal (!) context being
  1030 used here, which is not necessarily the same as the_context().
  1031 
  1032 * Command 'find_theorems': supports "*" wild-card in "name:"
  1033 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1034 support a specific search form (see ProofGeneral/CHANGES).
  1035 
  1036 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1037 by default, which means that "prems" (and also "fixed variables") are
  1038 suppressed from proof state output.  Note that the ProofGeneral
  1039 settings mechanism allows to change and save options persistently, but
  1040 older versions of Isabelle will fail to start up if a negative prems
  1041 limit is imposed.
  1042 
  1043 * Local theory targets may be specified by non-nested blocks of
  1044 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1045 contain definitions, theorems etc., including any derived mechanism
  1046 that has been implemented on top of these primitives.  This concept
  1047 generalizes the existing ``theorem (in ...)'' towards more versatility
  1048 and scalability.
  1049 
  1050 * Proof General interface: proper undo of final 'end' command;
  1051 discontinued Isabelle/classic mode (ML proof scripts).
  1052 
  1053 
  1054 *** Document preparation ***
  1055 
  1056 * Added antiquotation @{theory name} which prints the given name,
  1057 after checking that it refers to a valid ancestor theory in the
  1058 current context.
  1059 
  1060 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1061 check the given source text as ML type/structure, printing verbatim.
  1062 
  1063 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1064 "c args == rhs" given in the current context.  (Any number of
  1065 arguments may be given on the LHS.)
  1066 
  1067 
  1068 *** Pure ***
  1069 
  1070 * The 'class' package offers a combination of axclass and locale to
  1071 achieve Haskell-like type classes in Isabelle.  Definitions and
  1072 theorems within a class context produce both relative results (with
  1073 implicit parameters according to the locale context), and polymorphic
  1074 constants with qualified polymorphism (according to the class
  1075 context).  Within the body context of a 'class' target, a separate
  1076 syntax layer ("user space type system") takes care of converting
  1077 between global polymorphic consts and internal locale representation.
  1078 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1079 "isatool doc classes" provides a tutorial.
  1080 
  1081 * Generic code generator framework allows to generate executable
  1082 code for ML and Haskell (including Isabelle classes).  A short usage
  1083 sketch:
  1084 
  1085     internal compilation:
  1086         export_code <list of constants (term syntax)> in SML
  1087     writing SML code to a file:
  1088         export_code <list of constants (term syntax)> in SML <filename>
  1089     writing OCaml code to a file:
  1090         export_code <list of constants (term syntax)> in OCaml <filename>
  1091     writing Haskell code to a bunch of files:
  1092         export_code <list of constants (term syntax)> in Haskell <filename>
  1093 
  1094     evaluating closed propositions to True/False using code generation:
  1095         method ``eval''
  1096 
  1097 Reasonable default setup of framework in HOL.
  1098 
  1099 Theorem attributs for selecting and transforming function equations theorems:
  1100 
  1101     [code fun]:        select a theorem as function equation for a specific constant
  1102     [code fun del]:    deselect a theorem as function equation for a specific constant
  1103     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1104     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1105 
  1106 User-defined serializations (target in {SML, OCaml, Haskell}):
  1107 
  1108     code_const <and-list of constants (term syntax)>
  1109       {(target) <and-list of const target syntax>}+
  1110 
  1111     code_type <and-list of type constructors>
  1112       {(target) <and-list of type target syntax>}+
  1113 
  1114     code_instance <and-list of instances>
  1115       {(target)}+
  1116         where instance ::= <type constructor> :: <class>
  1117 
  1118     code_class <and_list of classes>
  1119       {(target) <and-list of class target syntax>}+
  1120         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1121 
  1122 code_instance and code_class only are effective to target Haskell.
  1123 
  1124 For example usage see src/HOL/ex/Codegenerator.thy and
  1125 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1126 generation from Isabelle/HOL theories is available via "isatool doc
  1127 codegen".
  1128 
  1129 * Code generator: consts in 'consts_code' Isar commands are now
  1130 referred to by usual term syntax (including optional type
  1131 annotations).
  1132 
  1133 * Command 'no_translations' removes translation rules from theory
  1134 syntax.
  1135 
  1136 * Overloaded definitions are now actually checked for acyclic
  1137 dependencies.  The overloading scheme is slightly more general than
  1138 that of Haskell98, although Isabelle does not demand an exact
  1139 correspondence to type class and instance declarations.
  1140 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1141 exotic versions of overloading -- at the discretion of the user!
  1142 
  1143 Polymorphic constants are represented via type arguments, i.e. the
  1144 instantiation that matches an instance against the most general
  1145 declaration given in the signature.  For example, with the declaration
  1146 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1147 as c(nat).  Overloading is essentially simultaneous structural
  1148 recursion over such type arguments.  Incomplete specification patterns
  1149 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1150 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1151 Command 'print_theory' outputs the normalized system of recursive
  1152 equations, see section "definitions".
  1153 
  1154 * Configuration options are maintained within the theory or proof
  1155 context (with name and type bool/int/string), providing a very simple
  1156 interface to a poor-man's version of general context data.  Tools may
  1157 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1158 these values using Config.get etc.  Users may change options via an
  1159 associated attribute of the same name.  This form of context
  1160 declaration works particularly well with commands 'declare' or
  1161 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1162 very easy to avoid global references, which would not observe Isar
  1163 toplevel undo/redo and fail to work with multithreading.
  1164 
  1165 Various global ML references of Pure and HOL have been turned into
  1166 configuration options:
  1167 
  1168   Unify.search_bound		unify_search_bound
  1169   Unify.trace_bound		unify_trace_bound
  1170   Unify.trace_simp		unify_trace_simp
  1171   Unify.trace_types		unify_trace_types
  1172   Simplifier.simp_depth_limit	simp_depth_limit
  1173   Blast.depth_limit		blast_depth_limit
  1174   DatatypeProp.dtK		datatype_distinctness_limit
  1175   fast_arith_neq_limit  	fast_arith_neq_limit
  1176   fast_arith_split_limit	fast_arith_split_limit
  1177 
  1178 * Named collections of theorems may be easily installed as context
  1179 data using the functor NamedThmsFun (see also
  1180 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1181 attributes; there is also a toplevel print command.  This facility is
  1182 just a common case of general context data, which is the preferred way
  1183 for anything more complex than just a list of facts in canonical
  1184 order.
  1185 
  1186 * Isar: command 'declaration' augments a local theory by generic
  1187 declaration functions written in ML.  This enables arbitrary content
  1188 being added to the context, depending on a morphism that tells the
  1189 difference of the original declaration context wrt. the application
  1190 context encountered later on.
  1191 
  1192 * Isar: proper interfaces for simplification procedures.  Command
  1193 'simproc_setup' declares named simprocs (with match patterns, and body
  1194 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1195 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1196 
  1197 * Isar: an extra pair of brackets around attribute declarations
  1198 abbreviates a theorem reference involving an internal dummy fact,
  1199 which will be ignored later --- only the effect of the attribute on
  1200 the background context will persist.  This form of in-place
  1201 declarations is particularly useful with commands like 'declare' and
  1202 'using', for example ``have A using [[simproc a]] by simp''.
  1203 
  1204 * Isar: method "assumption" (and implicit closing of subproofs) now
  1205 takes simple non-atomic goal assumptions into account: after applying
  1206 an assumption as a rule the resulting subgoals are solved by atomic
  1207 assumption steps.  This is particularly useful to finish 'obtain'
  1208 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1209 without referring to the original premise "!!x. P x ==> thesis" in the
  1210 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1211 more permissive.
  1212 
  1213 * Isar: implicit use of prems from the Isar proof context is
  1214 considered a legacy feature.  Common applications like ``have A .''
  1215 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1216 referencing facts explicitly here improves readability and
  1217 maintainability of proof texts.
  1218 
  1219 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1220 the obtained context from the course of reasoning!  For example:
  1221 
  1222   assume "EX x y. A x & B y"   -- "any previous fact"
  1223   then guess x and y by clarify
  1224 
  1225 This technique is potentially adventurous, depending on the facts and
  1226 proof tools being involved here.
  1227 
  1228 * Isar: known facts from the proof context may be specified as literal
  1229 propositions, using ASCII back-quote syntax.  This works wherever
  1230 named facts used to be allowed so far, in proof commands, proof
  1231 methods, attributes etc.  Literal facts are retrieved from the context
  1232 according to unification of type and term parameters.  For example,
  1233 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1234 theorems in the current context, then these are valid literal facts:
  1235 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1236 
  1237 There is also a proof method "fact" which does the same composition
  1238 for explicit goal states, e.g. the following proof texts coincide with
  1239 certain special cases of literal facts:
  1240 
  1241   have "A" by fact                 ==  note `A`
  1242   have "A ==> B" by fact           ==  note `A ==> B`
  1243   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1244   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1245 
  1246 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1247 outer syntax.  Thus symbolic identifiers may be used without
  1248 additional white space in declarations like this: ``assume *: A''.
  1249 
  1250 * Isar: 'print_facts' prints all local facts of the current context,
  1251 both named and unnamed ones.
  1252 
  1253 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1254 
  1255   def x == "t" and y == "u"
  1256 
  1257 * Isar: added command 'unfolding', which is structurally similar to
  1258 'using', but affects both the goal state and facts by unfolding given
  1259 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1260 'unfolded' attribute may be replaced by first-class proof text.
  1261 
  1262 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1263 and command 'unfolding' now all support object-level equalities
  1264 (potentially conditional).  The underlying notion of rewrite rule is
  1265 analogous to the 'rule_format' attribute, but *not* that of the
  1266 Simplifier (which is usually more generous).
  1267 
  1268 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1269 premises of a theorem by n. Useful in conjunction with drule.
  1270 
  1271 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1272 method expression within a sandbox consisting of the first N
  1273 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1274 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1275 simplifies all new goals that emerge from applying rule foo to the
  1276 originally first one.
  1277 
  1278 * Isar: schematic goals are no longer restricted to higher-order
  1279 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1280 expected.
  1281 
  1282 * Isar: the conclusion of a long theorem statement is now either
  1283 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1284 (essentially a disjunction of cases with local parameters and
  1285 assumptions).  The latter allows to express general elimination rules
  1286 adequately; in this notation common elimination rules look like this:
  1287 
  1288   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1289     assumes "EX x. P x"
  1290     obtains x where "P x"
  1291 
  1292   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1293     assumes "A & B"
  1294     obtains A and B
  1295 
  1296   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1297     assumes "A | B"
  1298     obtains
  1299       A
  1300     | B
  1301 
  1302 The subsequent classical rules even refer to the formal "thesis"
  1303 explicitly:
  1304 
  1305   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1306     obtains "~ thesis"
  1307 
  1308   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1309     obtains "thesis ==> something"
  1310 
  1311 The actual proof of an 'obtains' statement is analogous to that of the
  1312 Isar proof element 'obtain', only that there may be several cases.
  1313 Optional case names may be specified in parentheses; these will be
  1314 available both in the present proof and as annotations in the
  1315 resulting rule, for later use with the 'cases' method (cf. attribute
  1316 case_names).
  1317 
  1318 * Isar: the assumptions of a long theorem statement are available as
  1319 "assms" fact in the proof context.  This is more appropriate than the
  1320 (historical) "prems", which refers to all assumptions of the current
  1321 context, including those from the target locale, proof body etc.
  1322 
  1323 * Isar: 'print_statement' prints theorems from the current theory or
  1324 proof context in long statement form, according to the syntax of a
  1325 top-level lemma.
  1326 
  1327 * Isar: 'obtain' takes an optional case name for the local context
  1328 introduction rule (default "that").
  1329 
  1330 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1331 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1332 to occur.
  1333 
  1334 * Pure: syntax "CONST name" produces a fully internalized constant
  1335 according to the current context.  This is particularly useful for
  1336 syntax translations that should refer to internal constant
  1337 representations independently of name spaces.
  1338 
  1339 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1340 instead of "FOO ". This allows multiple binder declarations to coexist
  1341 in the same context.  INCOMPATIBILITY.
  1342 
  1343 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1344 primitive that also works in a locale context (both for constants and
  1345 fixed variables). Type declaration and internal syntactic representation
  1346 of given constants retrieved from the context. Likewise, the
  1347 'no_notation' command allows to remove given syntax annotations from the
  1348 current context.
  1349 
  1350 * Isar/locales: new derived specification elements 'axiomatization',
  1351 'definition', 'abbreviation', which support type-inference, admit
  1352 object-level specifications (equality, equivalence).  See also the
  1353 isar-ref manual.  Examples:
  1354 
  1355   axiomatization
  1356     eq  (infix "===" 50) where
  1357     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1358 
  1359   definition "f x y = x + y + 1"
  1360   definition g where "g x = f x x"
  1361 
  1362   abbreviation
  1363     neq  (infix "=!=" 50) where
  1364     "x =!= y == ~ (x === y)"
  1365 
  1366 These specifications may be also used in a locale context.  Then the
  1367 constants being introduced depend on certain fixed parameters, and the
  1368 constant name is qualified by the locale base name.  An internal
  1369 abbreviation takes care for convenient input and output, making the
  1370 parameters implicit and using the original short name.  See also
  1371 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1372 entities from a monomorphic theory.
  1373 
  1374 Presently, abbreviations are only available 'in' a target locale, but
  1375 not inherited by general import expressions.  Also note that
  1376 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1377 'translations' in common applications.  The "no_abbrevs" print mode
  1378 prevents folding of abbreviations in term output.
  1379 
  1380 Concrete syntax is attached to specified constants in internal form,
  1381 independently of name spaces.  The parse tree representation is
  1382 slightly different -- use 'notation' instead of raw 'syntax', and
  1383 'translations' with explicit "CONST" markup to accommodate this.
  1384 
  1385 * Pure/Isar: unified syntax for new-style specification mechanisms
  1386 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1387 full type inference and dummy patterns ("_").  For example:
  1388 
  1389   definition "K x _ = x"
  1390 
  1391   inductive conj for A B
  1392   where "A ==> B ==> conj A B"
  1393 
  1394 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1395 the current context.  Print mode "no_abbrevs" prevents inversion of
  1396 abbreviations on output.
  1397 
  1398 * Isar/locales: improved parameter handling: use of locales "var" and
  1399 "struct" no longer necessary; - parameter renamings are no longer
  1400 required to be injective.  For example, this allows to define
  1401 endomorphisms as locale endom = homom mult mult h.
  1402 
  1403 * Isar/locales: changed the way locales with predicates are defined.
  1404 Instead of accumulating the specification, the imported expression is
  1405 now an interpretation.  INCOMPATIBILITY: different normal form of
  1406 locale expressions.  In particular, in interpretations of locales with
  1407 predicates, goals repesenting already interpreted fragments are not
  1408 removed automatically.  Use methods `intro_locales' and
  1409 `unfold_locales'; see below.
  1410 
  1411 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1412 provide backward reasoning on locales predicates.  The methods are
  1413 aware of interpretations and discharge corresponding goals.
  1414 `intro_locales' is less aggressive then `unfold_locales' and does not
  1415 unfold predicates to assumptions.
  1416 
  1417 * Isar/locales: the order in which locale fragments are accumulated
  1418 has changed.  This enables to override declarations from fragments due
  1419 to interpretations -- for example, unwanted simp rules.
  1420 
  1421 * Isar/locales: interpretation in theories and proof contexts has been
  1422 extended.  One may now specify (and prove) equations, which are
  1423 unfolded in interpreted theorems.  This is useful for replacing
  1424 defined concepts (constants depending on locale parameters) by
  1425 concepts already existing in the target context.  Example:
  1426 
  1427   interpretation partial_order ["op <= :: [int, int] => bool"]
  1428     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1429 
  1430 Typically, the constant `partial_order.less' is created by a
  1431 definition specification element in the context of locale
  1432 partial_order.
  1433 
  1434 * Method "induct": improved internal context management to support
  1435 local fixes and defines on-the-fly. Thus explicit meta-level
  1436 connectives !!  and ==> are rarely required anymore in inductive goals
  1437 (using object-logic connectives for this purpose has been long
  1438 obsolete anyway). Common proof patterns are explained in
  1439 src/HOL/Induct/Common_Patterns.thy, see also
  1440 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1441 examples.
  1442 
  1443 * Method "induct": improved handling of simultaneous goals. Instead of
  1444 introducing object-level conjunction, the statement is now split into
  1445 several conclusions, while the corresponding symbolic cases are nested
  1446 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1447 see src/HOL/Induct/Common_Patterns.thy, for example.
  1448 
  1449 * Method "induct": mutual induction rules are now specified as a list
  1450 of rule sharing the same induction cases. HOL packages usually provide
  1451 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1452 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1453 mutual induction rules differently, i.e. like this:
  1454 
  1455   (induct rule: foo_bar.inducts)
  1456   (induct set: foo bar)
  1457   (induct pred: foo bar)
  1458   (induct type: foo bar)
  1459 
  1460 The ML function ProjectRule.projections turns old-style rules into the
  1461 new format.
  1462 
  1463 * Method "coinduct": dual of induction, see
  1464 src/HOL/Library/Coinductive_List.thy for various examples.
  1465 
  1466 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1467 considered a legacy feature.
  1468 
  1469 * Attribute "symmetric" produces result with standardized schematic
  1470 variables (index 0).  Potential INCOMPATIBILITY.
  1471 
  1472 * Simplifier: by default the simplifier trace only shows top level
  1473 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1474 default. Thus there is less danger of being flooded by the trace. The
  1475 trace indicates where parts have been suppressed.
  1476   
  1477 * Provers/classical: removed obsolete classical version of elim_format
  1478 attribute; classical elim/dest rules are now treated uniformly when
  1479 manipulating the claset.
  1480 
  1481 * Provers/classical: stricter checks to ensure that supplied intro,
  1482 dest and elim rules are well-formed; dest and elim rules must have at
  1483 least one premise.
  1484 
  1485 * Provers/classical: attributes dest/elim/intro take an optional
  1486 weight argument for the rule (just as the Pure versions).  Weights are
  1487 ignored by automated tools, but determine the search order of single
  1488 rule steps.
  1489 
  1490 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1491 where the body does not mention the bound variable.  Note that dummy
  1492 patterns implicitly depend on their context of bounds, which makes
  1493 "{_. _}" match any set comprehension as expected.  Potential
  1494 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1495 constant "_idtdummy" in the binding position.
  1496 
  1497 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1498 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1499 for example "A -> B" => "Pi A (%_. B)".
  1500 
  1501 * Pure: 'class_deps' command visualizes the subclass relation, using
  1502 the graph browser tool.
  1503 
  1504 * Pure: 'print_theory' now suppresses certain internal declarations by
  1505 default; use '!' option for full details.
  1506 
  1507 
  1508 *** HOL ***
  1509 
  1510 * Method "metis" proves goals by applying the Metis general-purpose
  1511 resolution prover (see also http://gilith.com/software/metis/).
  1512 Examples are in the directory MetisExamples.  WARNING: the
  1513 Isabelle/HOL-Metis integration does not yet work properly with
  1514 multi-threading.
  1515   
  1516 * Command 'sledgehammer' invokes external automatic theorem provers as
  1517 background processes.  It generates calls to the "metis" method if
  1518 successful. These can be pasted into the proof.  Users do not have to
  1519 wait for the automatic provers to return.  WARNING: does not really
  1520 work with multi-threading.
  1521 
  1522 * New "auto_quickcheck" feature tests outermost goal statements for
  1523 potential counter-examples.  Controlled by ML references
  1524 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1525 5000 milliseconds).  Fails silently if statements is outside of
  1526 executable fragment, or any other codgenerator problem occurs.
  1527 
  1528 * New constant "undefined" with axiom "undefined x = undefined".
  1529 
  1530 * Added class "HOL.eq", allowing for code generation with polymorphic
  1531 equality.
  1532 
  1533 * Some renaming of class constants due to canonical name prefixing in
  1534 the new 'class' package:
  1535 
  1536     HOL.abs ~> HOL.abs_class.abs
  1537     HOL.divide ~> HOL.divide_class.divide
  1538     0 ~> HOL.zero_class.zero
  1539     1 ~> HOL.one_class.one
  1540     op + ~> HOL.plus_class.plus
  1541     op - ~> HOL.minus_class.minus
  1542     uminus ~> HOL.minus_class.uminus
  1543     op * ~> HOL.times_class.times
  1544     op < ~> HOL.ord_class.less
  1545     op <= > HOL.ord_class.less_eq
  1546     Nat.power ~> Power.power_class.power
  1547     Nat.size ~> Nat.size_class.size
  1548     Numeral.number_of ~> Numeral.number_class.number_of
  1549     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1550     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1551     Orderings.min ~> Orderings.ord_class.min
  1552     Orderings.max ~> Orderings.ord_class.max
  1553     Divides.op div ~> Divides.div_class.div
  1554     Divides.op mod ~> Divides.div_class.mod
  1555     Divides.op dvd ~> Divides.div_class.dvd
  1556 
  1557 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1558 
  1559 a) User-defined constants using any of the names "plus", "minus",
  1560 "times", "less" or "less_eq". The standard syntax translations for
  1561 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1562 names.
  1563 
  1564 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1565 INCOMPATIBILITY: use more specific names.
  1566 
  1567 c) Permutative equations (e.g. "a + b = b + a")
  1568 Since the change of names also changes the order of terms, permutative
  1569 rewrite rules may get applied in a different order. Experience shows
  1570 that this is rarely the case (only two adaptions in the whole Isabelle
  1571 distribution).  INCOMPATIBILITY: rewrite proofs
  1572 
  1573 d) ML code directly refering to constant names
  1574 This in general only affects hand-written proof tactics, simprocs and
  1575 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1576 Consider using @{const_name} antiquotation.
  1577 
  1578 * New class "default" with associated constant "default".
  1579 
  1580 * Function "sgn" is now overloaded and available on int, real, complex
  1581 (and other numeric types), using class "sgn".  Two possible defs of
  1582 sgn are given as equational assumptions in the classes sgn_if and
  1583 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1584 INCOMPATIBILITY.
  1585 
  1586 * Locale "partial_order" now unified with class "order" (cf. theory
  1587 Orderings), added parameter "less".  INCOMPATIBILITY.
  1588 
  1589 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1590 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1591 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1592 
  1593 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1594 changed order of proof goals in instance proofs.
  1595 
  1596 * The transitivity reasoner for partial and linear orders is set up
  1597 for classes "order" and "linorder".  Instances of the reasoner are available
  1598 in all contexts importing or interpreting the corresponding locales.
  1599 Method "order" invokes the reasoner separately; the reasoner
  1600 is also integrated with the Simplifier as a solver.  Diagnostic
  1601 command 'print_orders' shows the available instances of the reasoner
  1602 in the current context.
  1603 
  1604 * Localized monotonicity predicate in theory "Orderings"; integrated
  1605 lemmas max_of_mono and min_of_mono with this predicate.
  1606 INCOMPATIBILITY.
  1607 
  1608 * Formulation of theorem "dense" changed slightly due to integration
  1609 with new class dense_linear_order.
  1610 
  1611 * Uniform lattice theory development in HOL.
  1612 
  1613     constants "meet" and "join" now named "inf" and "sup"
  1614     constant "Meet" now named "Inf"
  1615 
  1616     classes "meet_semilorder" and "join_semilorder" now named
  1617       "lower_semilattice" and "upper_semilattice"
  1618     class "lorder" now named "lattice"
  1619     class "comp_lat" now named "complete_lattice"
  1620 
  1621     Instantiation of lattice classes allows explicit definitions
  1622     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1623 
  1624   INCOMPATIBILITY.  Theorem renames:
  1625 
  1626     meet_left_le            ~> inf_le1
  1627     meet_right_le           ~> inf_le2
  1628     join_left_le            ~> sup_ge1
  1629     join_right_le           ~> sup_ge2
  1630     meet_join_le            ~> inf_sup_ord
  1631     le_meetI                ~> le_infI
  1632     join_leI                ~> le_supI
  1633     le_meet                 ~> le_inf_iff
  1634     le_join                 ~> ge_sup_conv
  1635     meet_idempotent         ~> inf_idem
  1636     join_idempotent         ~> sup_idem
  1637     meet_comm               ~> inf_commute
  1638     join_comm               ~> sup_commute
  1639     meet_leI1               ~> le_infI1
  1640     meet_leI2               ~> le_infI2
  1641     le_joinI1               ~> le_supI1
  1642     le_joinI2               ~> le_supI2
  1643     meet_assoc              ~> inf_assoc
  1644     join_assoc              ~> sup_assoc
  1645     meet_left_comm          ~> inf_left_commute
  1646     meet_left_idempotent    ~> inf_left_idem
  1647     join_left_comm          ~> sup_left_commute
  1648     join_left_idempotent    ~> sup_left_idem
  1649     meet_aci                ~> inf_aci
  1650     join_aci                ~> sup_aci
  1651     le_def_meet             ~> le_iff_inf
  1652     le_def_join             ~> le_iff_sup
  1653     join_absorp2            ~> sup_absorb2
  1654     join_absorp1            ~> sup_absorb1
  1655     meet_absorp1            ~> inf_absorb1
  1656     meet_absorp2            ~> inf_absorb2
  1657     meet_join_absorp        ~> inf_sup_absorb
  1658     join_meet_absorp        ~> sup_inf_absorb
  1659     distrib_join_le         ~> distrib_sup_le
  1660     distrib_meet_le         ~> distrib_inf_le
  1661 
  1662     add_meet_distrib_left   ~> add_inf_distrib_left
  1663     add_join_distrib_left   ~> add_sup_distrib_left
  1664     is_join_neg_meet        ~> is_join_neg_inf
  1665     is_meet_neg_join        ~> is_meet_neg_sup
  1666     add_meet_distrib_right  ~> add_inf_distrib_right
  1667     add_join_distrib_right  ~> add_sup_distrib_right
  1668     add_meet_join_distribs  ~> add_sup_inf_distribs
  1669     join_eq_neg_meet        ~> sup_eq_neg_inf
  1670     meet_eq_neg_join        ~> inf_eq_neg_sup
  1671     add_eq_meet_join        ~> add_eq_inf_sup
  1672     meet_0_imp_0            ~> inf_0_imp_0
  1673     join_0_imp_0            ~> sup_0_imp_0
  1674     meet_0_eq_0             ~> inf_0_eq_0
  1675     join_0_eq_0             ~> sup_0_eq_0
  1676     neg_meet_eq_join        ~> neg_inf_eq_sup
  1677     neg_join_eq_meet        ~> neg_sup_eq_inf
  1678     join_eq_if              ~> sup_eq_if
  1679 
  1680     mono_meet               ~> mono_inf
  1681     mono_join               ~> mono_sup
  1682     meet_bool_eq            ~> inf_bool_eq
  1683     join_bool_eq            ~> sup_bool_eq
  1684     meet_fun_eq             ~> inf_fun_eq
  1685     join_fun_eq             ~> sup_fun_eq
  1686     meet_set_eq             ~> inf_set_eq
  1687     join_set_eq             ~> sup_set_eq
  1688     meet1_iff               ~> inf1_iff
  1689     meet2_iff               ~> inf2_iff
  1690     meet1I                  ~> inf1I
  1691     meet2I                  ~> inf2I
  1692     meet1D1                 ~> inf1D1
  1693     meet2D1                 ~> inf2D1
  1694     meet1D2                 ~> inf1D2
  1695     meet2D2                 ~> inf2D2
  1696     meet1E                  ~> inf1E
  1697     meet2E                  ~> inf2E
  1698     join1_iff               ~> sup1_iff
  1699     join2_iff               ~> sup2_iff
  1700     join1I1                 ~> sup1I1
  1701     join2I1                 ~> sup2I1
  1702     join1I1                 ~> sup1I1
  1703     join2I2                 ~> sup1I2
  1704     join1CI                 ~> sup1CI
  1705     join2CI                 ~> sup2CI
  1706     join1E                  ~> sup1E
  1707     join2E                  ~> sup2E
  1708 
  1709     is_meet_Meet            ~> is_meet_Inf
  1710     Meet_bool_def           ~> Inf_bool_def
  1711     Meet_fun_def            ~> Inf_fun_def
  1712     Meet_greatest           ~> Inf_greatest
  1713     Meet_lower              ~> Inf_lower
  1714     Meet_set_def            ~> Inf_set_def
  1715 
  1716     Sup_def                 ~> Sup_Inf
  1717     Sup_bool_eq             ~> Sup_bool_def
  1718     Sup_fun_eq              ~> Sup_fun_def
  1719     Sup_set_eq              ~> Sup_set_def
  1720 
  1721     listsp_meetI            ~> listsp_infI
  1722     listsp_meet_eq          ~> listsp_inf_eq
  1723 
  1724     meet_min                ~> inf_min
  1725     join_max                ~> sup_max
  1726 
  1727 * Added syntactic class "size"; overloaded constant "size" now has
  1728 type "'a::size ==> bool"
  1729 
  1730 * Internal reorganisation of `size' of datatypes: size theorems
  1731 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1732 simplification rules by default!); theorems "prod.size" now named
  1733 "*.size".
  1734 
  1735 * Class "div" now inherits from class "times" rather than "type".
  1736 INCOMPATIBILITY.
  1737 
  1738 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1739 Linorder etc.  have disappeared; operations defined in terms of
  1740 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1741 
  1742 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1743 
  1744 * HOL-Word: New extensive library and type for generic, fixed size
  1745 machine words, with arithemtic, bit-wise, shifting and rotating
  1746 operations, reflection into int, nat, and bool lists, automation for
  1747 linear arithmetic (by automatic reflection into nat or int), including
  1748 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1749 arithmetic type classes, supporting automatic simplification of
  1750 numerals on all operations.
  1751 
  1752 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1753 
  1754 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1755 
  1756 * Code generator library theories:
  1757   - Code_Integer represents HOL integers by big integer literals in target
  1758     languages.
  1759   - Code_Char represents HOL characters by character literals in target
  1760     languages.
  1761   - Code_Char_chr like Code_Char, but also offers treatment of character
  1762     codes; includes Code_Integer.
  1763   - Executable_Set allows to generate code for finite sets using lists.
  1764   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1765     denominator).
  1766   - Executable_Real implements a subset of real numbers, namly those
  1767     representable by rational numbers.
  1768   - Efficient_Nat implements natural numbers by integers, which in general will
  1769     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1770     includes Code_Integer.
  1771   - Code_Index provides an additional datatype index which is mapped to
  1772     target-language built-in integers.
  1773   - Code_Message provides an additional datatype message_string which is isomorphic to
  1774     strings; messages are mapped to target-language strings.
  1775 
  1776 * New package for inductive predicates
  1777 
  1778   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1779 
  1780     inductive
  1781       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1782       for z_1 :: U_1 and ... and z_n :: U_m
  1783     where
  1784       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1785     | ...
  1786 
  1787   with full support for type-inference, rather than
  1788 
  1789     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1790 
  1791     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1792     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1793 
  1794     inductive "s z_1 ... z_m"
  1795     intros
  1796       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1797       ...
  1798 
  1799   For backward compatibility, there is a wrapper allowing inductive
  1800   sets to be defined with the new package via
  1801 
  1802     inductive_set
  1803       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1804       for z_1 :: U_1 and ... and z_n :: U_m
  1805     where
  1806       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1807     | ...
  1808 
  1809   or
  1810 
  1811     inductive_set
  1812       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1813       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1814       for z_1 :: U_1 and ... and z_n :: U_m
  1815     where
  1816       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1817     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1818     | ...
  1819 
  1820   if the additional syntax "p ..." is required.
  1821 
  1822   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1823   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1824 
  1825   INCOMPATIBILITIES:
  1826 
  1827   - Since declaration and definition of inductive sets or predicates
  1828     is no longer separated, abbreviations involving the newly
  1829     introduced sets or predicates must be specified together with the
  1830     introduction rules after the 'where' keyword (see above), rather
  1831     than before the actual inductive definition.
  1832 
  1833   - The variables in induction and elimination rules are now
  1834     quantified in the order of their occurrence in the introduction
  1835     rules, rather than in alphabetical order. Since this may break
  1836     some proofs, these proofs either have to be repaired, e.g. by
  1837     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1838     statements of the form
  1839 
  1840       case (rule_i a_i_1 ... a_i_{k_i})
  1841 
  1842     or the old order of quantification has to be restored by explicitly adding
  1843     meta-level quantifiers in the introduction rules, i.e.
  1844 
  1845       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  1846 
  1847   - The format of the elimination rules is now
  1848 
  1849       p z_1 ... z_m x_1 ... x_n ==>
  1850         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1851         ==> ... ==> P
  1852 
  1853     for predicates and
  1854 
  1855       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1856         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1857         ==> ... ==> P
  1858 
  1859     for sets rather than
  1860 
  1861       x : s z_1 ... z_m ==>
  1862         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1863         ==> ... ==> P
  1864 
  1865     This may require terms in goals to be expanded to n-tuples
  1866     (e.g. using case_tac or simplification with the split_paired_all
  1867     rule) before the above elimination rule is applicable.
  1868 
  1869   - The elimination or case analysis rules for (mutually) inductive
  1870     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1871     list of rules "p_1_..._p_k.elims" is no longer available.
  1872 
  1873 * New package "function"/"fun" for general recursive functions,
  1874 supporting mutual and nested recursion, definitions in local contexts,
  1875 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1876 for small examples, and the separate tutorial on the function
  1877 package. The old recdef "package" is still available as before, but
  1878 users are encouraged to use the new package.
  1879 
  1880 * Method "lexicographic_order" automatically synthesizes termination
  1881 relations as lexicographic combinations of size measures. 
  1882 
  1883 * Case-expressions allow arbitrary constructor-patterns (including
  1884 "_") and take their order into account, like in functional
  1885 programming.  Internally, this is translated into nested
  1886 case-expressions; missing cases are added and mapped to the predefined
  1887 constant "undefined". In complicated cases printing may no longer show
  1888 the original input but the internal form. Lambda-abstractions allow
  1889 the same form of pattern matching: "% pat1 => e1 | ..." is an
  1890 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  1891 variable.
  1892 
  1893 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  1894 is an abbreviation for "of_nat :: nat => int". The simplification
  1895 rules for "of_nat" have been changed to work like "int" did
  1896 previously.  Potential INCOMPATIBILITY:
  1897   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  1898   - of_nat_diff and of_nat_mult are no longer default simp rules
  1899 
  1900 * Method "algebra" solves polynomial equations over (semi)rings using
  1901 Groebner bases. The (semi)ring structure is defined by locales and the
  1902 tool setup depends on that generic context. Installing the method for
  1903 a specific type involves instantiating the locale and possibly adding
  1904 declarations for computation on the coefficients.  The method is
  1905 already instantiated for natural numbers and for the axiomatic class
  1906 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  1907 CALCULEMUS 2007 for the general principles underlying this
  1908 architecture of context-aware proof-tools.
  1909 
  1910 * Method "ferrack" implements quantifier elimination over
  1911 special-purpose dense linear orders using locales (analogous to
  1912 "algebra"). The method is already installed for class
  1913 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  1914 rat, etc.
  1915 
  1916 * Former constant "List.op @" now named "List.append".  Use ML
  1917 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  1918 circumvent possible incompatibilities when working on ML level.
  1919 
  1920 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1921 
  1922 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1923 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1924 
  1925 * New syntax for Haskell-like list comprehension (input only), eg.
  1926 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1927 
  1928 * The special syntax for function "filter" has changed from [x :
  1929 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1930 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1931 
  1932 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1933 defined on nat only, as an abbreviation for [a..<Suc b]
  1934 INCOMPATIBILITY.
  1935 
  1936 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1937 
  1938 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1939 
  1940 * New lemma collection field_simps (an extension of ring_simps) for
  1941 manipulating (in)equations involving division. Multiplies with all
  1942 denominators that can be proved to be non-zero (in equations) or
  1943 positive/negative (in inequations).
  1944 
  1945 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1946 have been improved and renamed to ring_simps, group_simps and
  1947 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1948 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1949 
  1950 * Theory Library/Commutative_Ring: switched from recdef to function
  1951 package; constants add, mul, pow now curried.  Infix syntax for
  1952 algebraic operations.
  1953 
  1954 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1955 INCOMPATIBILITY.
  1956 
  1957 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1958 INCOMPATIBILITY.
  1959 
  1960 * HOL/records: generalised field-update to take a function on the
  1961 field rather than the new value: r(|A := x|) is translated to A_update
  1962 (K x) r The K-combinator that is internally used is called K_record.
  1963 INCOMPATIBILITY: Usage of the plain update functions has to be
  1964 adapted.
  1965  
  1966 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1967 * x = 0, which are required for a semiring.  Richer structures do not
  1968 inherit from semiring_0 anymore, because this property is a theorem
  1969 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1970 there is more to prove, but this is mostly trivial.
  1971 
  1972 * Class "recpower" is generalized to arbitrary monoids, not just
  1973 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1974 commutativity or semiring properties additionally.
  1975 
  1976 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1977 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1978 better use 'abbreviation'.
  1979 
  1980 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1981 
  1982 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1983 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1984 significant changes for setting up numeral syntax for types:
  1985   - New constants Numeral.pred and Numeral.succ instead
  1986       of former Numeral.bin_pred and Numeral.bin_succ.
  1987   - Use integer operations instead of bin_add, bin_mult and so on.
  1988   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1989   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1990 
  1991 See src/HOL/Integ/IntArith.thy for an example setup.
  1992 
  1993 * Command 'normal_form' computes the normal form of a term that may
  1994 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1995 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1996 heavy-duty computations because the functions are compiled to ML
  1997 first.  Correspondingly, a method "normalization" is provided.  See
  1998 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1999 
  2000 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2001 25 like -->); output depends on the "iff" print_mode, the default is
  2002 "A = B" (with priority 50).
  2003 
  2004 * Relations less (<) and less_eq (<=) are also available on type bool.
  2005 Modified syntax to disallow nesting without explicit parentheses,
  2006 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2007 INCOMPATIBILITY.
  2008 
  2009 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2010 
  2011 * Relation composition operator "op O" now has precedence 75 and binds
  2012 stronger than union and intersection. INCOMPATIBILITY.
  2013 
  2014 * The old set interval syntax "{m..n(}" (and relatives) has been
  2015 removed.  Use "{m..<n}" (and relatives) instead.
  2016 
  2017 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2018 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2019 ``declare [[simproc del: neq]]''.
  2020 
  2021 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2022 True/False.
  2023 
  2024 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2025 
  2026 * Theorem setsum_mult renamed to setsum_right_distrib.
  2027 
  2028 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2029 ``rule'' method.
  2030 
  2031 * Reimplemented methods "sat" and "satx", with several improvements:
  2032 goals no longer need to be stated as "<prems> ==> False", equivalences
  2033 (i.e. "=" on type bool) are handled, variable names of the form
  2034 "lit_<n>" are no longer reserved, significant speedup.
  2035 
  2036 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2037 zChaff is still supported as well.
  2038 
  2039 * 'inductive' and 'datatype': provide projections of mutual rules,
  2040 bundled as foo_bar.inducts;
  2041 
  2042 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2043 Library.
  2044 
  2045 * Library: moved theory Accessible_Part to main HOL.
  2046 
  2047 * Library: added theory Coinductive_List of potentially infinite lists
  2048 as greatest fixed-point.
  2049 
  2050 * Library: added theory AssocList which implements (finite) maps as
  2051 association lists.
  2052 
  2053 * Method "evaluation" solves goals (i.e. a boolean expression)
  2054 efficiently by compiling it to ML.  The goal is "proved" (via an
  2055 oracle) if it evaluates to True.
  2056 
  2057 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2058 also when invoked by the simplifier.  This results in the Simplifier
  2059 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2060 Configuration option fast_arith_split_limit=0 recovers the old
  2061 behavior.
  2062 
  2063 * Support for hex (0x20) and binary (0b1001) numerals.
  2064 
  2065 * New method: reify eqs (t), where eqs are equations for an
  2066 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2067 parameter, computes a term s::'b and a list xs::'a list and proves the
  2068 theorem I xs s = t. This is also known as reification or quoting. The
  2069 resulting theorem is applied to the subgoal to substitute t with I xs
  2070 s.  If t is omitted, the subgoal itself is reified.
  2071 
  2072 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2073 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2074 where f is supposed to be a computable function (in the sense of code
  2075 generattion). The method uses reify to compute s and xs as above then
  2076 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2077 r and finally gets the theorem t = r, which is again applied to the
  2078 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2079 
  2080 * Reflection: Automatic reification now handels binding, an example is
  2081 available in src/HOL/ex/ReflectionEx.thy
  2082 
  2083 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2084 command 'statespace' that is similar to 'record', but introduces an
  2085 abstract specification based on the locale infrastructure instead of
  2086 HOL types.  This leads to extra flexibility in composing state spaces,
  2087 in particular multiple inheritance and renaming of components.
  2088 
  2089 
  2090 *** HOL-Complex ***
  2091 
  2092 * Hyperreal: Functions root and sqrt are now defined on negative real
  2093 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2094 Nonnegativity side conditions have been removed from many lemmas, so
  2095 that more subgoals may now be solved by simplification; potential
  2096 INCOMPATIBILITY.
  2097 
  2098 * Real: new type classes formalize real normed vector spaces and
  2099 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2100 and norm :: 'a => real.
  2101 
  2102 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2103 reals into other types. The overloaded constant Reals :: 'a set is now
  2104 defined as range of_real; potential INCOMPATIBILITY.
  2105 
  2106 * Real: proper support for ML code generation, including 'quickcheck'.
  2107 Reals are implemented as arbitrary precision rationals.
  2108 
  2109 * Hyperreal: Several constants that previously worked only for the
  2110 reals have been generalized, so they now work over arbitrary vector
  2111 spaces. Type annotations may need to be added in some cases; potential
  2112 INCOMPATIBILITY.
  2113 
  2114   Infinitesimal  :: ('a::real_normed_vector) star set
  2115   HFinite        :: ('a::real_normed_vector) star set
  2116   HInfinite      :: ('a::real_normed_vector) star set
  2117   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2118   monad          :: ('a::real_normed_vector) star => 'a star set
  2119   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2120   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2121   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2122   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2123   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2124   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2125   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2126   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2127   sgn            :: 'a::real_normed_vector => 'a
  2128   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2129 
  2130 * Complex: Some complex-specific constants are now abbreviations for
  2131 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2132 hnorm.  Other constants have been entirely removed in favor of the
  2133 polymorphic versions (INCOMPATIBILITY):
  2134 
  2135   approx        <-- capprox
  2136   HFinite       <-- CFinite
  2137   HInfinite     <-- CInfinite
  2138   Infinitesimal <-- CInfinitesimal
  2139   monad         <-- cmonad
  2140   galaxy        <-- cgalaxy
  2141   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2142   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2143   (ns)deriv     <-- (ns)cderiv
  2144 
  2145 
  2146 *** HOL-Algebra ***
  2147 
  2148 * Formalisation of ideals and the quotient construction over rings.
  2149 
  2150 * Order and lattice theory no longer based on records.
  2151 INCOMPATIBILITY.
  2152 
  2153 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2154 greatest_closed.  INCOMPATIBILITY.
  2155 
  2156 * Method algebra is now set up via an attribute.  For examples see
  2157 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2158 of algebraic structures.
  2159 
  2160 * Renamed theory CRing to Ring.
  2161 
  2162 
  2163 *** HOL-Nominal ***
  2164 
  2165 * Substantial, yet incomplete support for nominal datatypes (binding
  2166 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2167 src/HOL/Nominal/Examples.  Prospective users should consult
  2168 http://isabelle.in.tum.de/nominal/
  2169 
  2170 
  2171 *** ML ***
  2172 
  2173 * ML basics: just one true type int, which coincides with IntInf.int
  2174 (even on SML/NJ).
  2175 
  2176 * ML within Isar: antiquotations allow to embed statically-checked
  2177 formal entities in the source, referring to the context available at
  2178 compile-time.  For example:
  2179 
  2180 ML {* @{sort "{zero,one}"} *}
  2181 ML {* @{typ "'a => 'b"} *}
  2182 ML {* @{term "%x. x"} *}
  2183 ML {* @{prop "x == y"} *}
  2184 ML {* @{ctyp "'a => 'b"} *}
  2185 ML {* @{cterm "%x. x"} *}
  2186 ML {* @{cprop "x == y"} *}
  2187 ML {* @{thm asm_rl} *}
  2188 ML {* @{thms asm_rl} *}
  2189 ML {* @{type_name c} *}
  2190 ML {* @{type_syntax c} *}
  2191 ML {* @{const_name c} *}
  2192 ML {* @{const_syntax c} *}
  2193 ML {* @{context} *}
  2194 ML {* @{theory} *}
  2195 ML {* @{theory Pure} *}
  2196 ML {* @{theory_ref} *}
  2197 ML {* @{theory_ref Pure} *}
  2198 ML {* @{simpset} *}
  2199 ML {* @{claset} *}
  2200 ML {* @{clasimpset} *}
  2201 
  2202 The same works for sources being ``used'' within an Isar context.
  2203 
  2204 * ML in Isar: improved error reporting; extra verbosity with
  2205 ML_Context.trace enabled.
  2206 
  2207 * Pure/General/table.ML: the join operations now works via exceptions
  2208 DUP/SAME instead of type option. This is simpler in simple cases, and
  2209 admits slightly more efficient complex applications.
  2210 
  2211 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2212 use Context.generic instead of just theory.
  2213 
  2214 * Pure: datatype Context.generic joins theory/Proof.context and
  2215 provides some facilities for code that works in either kind of
  2216 context, notably GenericDataFun for uniform theory and proof data.
  2217 
  2218 * Pure: simplified internal attribute type, which is now always
  2219 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2220 local (Proof.context) attributes have been discontinued, while
  2221 minimizing code duplication. Thm.rule_attribute and
  2222 Thm.declaration_attribute build canonical attributes; see also structure
  2223 Context for further operations on Context.generic, notably
  2224 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2225 declarations and definitions.
  2226 
  2227 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2228 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2229 init only required for impure data. INCOMPATIBILITY: empty really need
  2230 to be empty (no dependencies on theory content!)
  2231 
  2232 * Pure/kernel: consts certification ignores sort constraints given in
  2233 signature declarations. (This information is not relevant to the
  2234 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2235 potential INCOMPATIBILITY.
  2236 
  2237 * Pure: axiomatic type classes are now purely definitional, with
  2238 explicit proofs of class axioms and super class relations performed
  2239 internally. See Pure/axclass.ML for the main internal interfaces --
  2240 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2241 AxClass.axiomatize_class/classrel/arity supersede
  2242 Sign.add_classes/classrel/arities.
  2243 
  2244 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2245 global/local versions on theory vs. Proof.context have been
  2246 discontinued; Attrib.syntax and Method.syntax have been adapted
  2247 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2248 attributes, methods, etc.
  2249 
  2250 * Pure: several functions of signature "... -> theory -> theory * ..."
  2251 have been reoriented to "... -> theory -> ... * theory" in order to
  2252 allow natural usage in combination with the ||>, ||>>, |-> and
  2253 fold_map combinators.
  2254 
  2255 * Pure: official theorem names (closed derivations) and additional
  2256 comments (tags) are now strictly separate.  Name hints -- which are
  2257 maintained as tags -- may be attached any time without affecting the
  2258 derivation.
  2259 
  2260 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2261 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2262 achieve the old behaviour.
  2263 
  2264 * Pure: the "Goal" constant is now called "prop", supporting a
  2265 slightly more general idea of ``protecting'' meta-level rule
  2266 statements.
  2267 
  2268 * Pure: Logic.(un)varify only works in a global context, which is now
  2269 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2270 Logic.legacy_(un)varify as temporary workaround.
  2271 
  2272 * Pure: structure Name provides scalable operations for generating
  2273 internal variable names, notably Name.variants etc.  This replaces
  2274 some popular functions from term.ML:
  2275 
  2276   Term.variant		->  Name.variant
  2277   Term.variantlist	->  Name.variant_list
  2278   Term.invent_names	->  Name.invent_list
  2279 
  2280 Note that low-level renaming rarely occurs in new code -- operations
  2281 from structure Variable are used instead (see below).
  2282 
  2283 * Pure: structure Variable provides fundamental operations for proper
  2284 treatment of fixed/schematic variables in a context.  For example,
  2285 Variable.import introduces fixes for schematics of given facts and
  2286 Variable.export reverses the effect (up to renaming) -- this replaces
  2287 various freeze_thaw operations.
  2288 
  2289 * Pure: structure Goal provides simple interfaces for
  2290 init/conclude/finish and tactical prove operations (replacing former
  2291 Tactic.prove).  Goal.prove is the canonical way to prove results
  2292 within a given context; Goal.prove_global is a degraded version for
  2293 theory level goals, including a global Drule.standard.  Note that
  2294 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2295 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2296 in a locale context).
  2297 
  2298 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2299 and type checking (Syntax.check_term etc.), with common combinations
  2300 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2301 which are considered legacy and await removal.
  2302 
  2303 * Pure/Syntax: generic interfaces for type unchecking
  2304 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2305 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2306 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2307 available for convenience, but refer to the very same operations using
  2308 a mere theory instead of a full context.
  2309 
  2310 * Isar: simplified treatment of user-level errors, using exception
  2311 ERROR of string uniformly.  Function error now merely raises ERROR,
  2312 without any side effect on output channels.  The Isar toplevel takes
  2313 care of proper display of ERROR exceptions.  ML code may use plain
  2314 handle/can/try; cat_error may be used to concatenate errors like this:
  2315 
  2316   ... handle ERROR msg => cat_error msg "..."
  2317 
  2318 Toplevel ML code (run directly or through the Isar toplevel) may be
  2319 embedded into the Isar toplevel with exception display/debug like
  2320 this:
  2321 
  2322   Isar.toplevel (fn () => ...)
  2323 
  2324 INCOMPATIBILITY, removed special transform_error facilities, removed
  2325 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2326 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2327 -- use plain ERROR instead.
  2328 
  2329 * Isar: theory setup now has type (theory -> theory), instead of a
  2330 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2331 
  2332 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2333 ProofContext.debug/verbose flags.
  2334 
  2335 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2336 theory before entering a proof state.  Transactions now always see a
  2337 quasi-functional intermediate checkpoint, both in interactive and
  2338 batch mode.
  2339 
  2340 * Isar: simplified interfaces for outer syntax.  Renamed
  2341 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2342 OuterSyntax.add_parsers -- this functionality is now included in
  2343 OuterSyntax.command etc.  INCOMPATIBILITY.
  2344 
  2345 * Simplifier: the simpset of a running simplification process now
  2346 contains a proof context (cf. Simplifier.the_context), which is the
  2347 very context that the initial simpset has been retrieved from (by
  2348 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2349 (solver, looper etc.) may depend on arbitrary proof data.
  2350 
  2351 * Simplifier.inherit_context inherits the proof context (plus the
  2352 local bounds) of the current simplification process; any simproc
  2353 etc. that calls the Simplifier recursively should do this!  Removed
  2354 former Simplifier.inherit_bounds, which is already included here --
  2355 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2356 specify an explicit context using Simplifier.context/theory_context.
  2357 
  2358 * Simplifier/Classical Reasoner: more abstract interfaces
  2359 change_simpset/claset for modifying the simpset/claset reference of a
  2360 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2361 INCOMPATIBILITY.
  2362 
  2363 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2364 "Trueprop" etc.
  2365 
  2366 
  2367 *** System ***
  2368 
  2369 * settings: the default heap location within ISABELLE_HOME_USER now
  2370 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2371 Isabelle installations.
  2372 
  2373 * isabelle-process: option -S (secure mode) disables some critical
  2374 operations, notably runtime compilation and evaluation of ML source
  2375 code.
  2376 
  2377 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2378 
  2379 * Support for parallel execution, using native multicore support of
  2380 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2381 independent theories, according to the given theory header
  2382 specifications. The maximum number of worker threads is specified via
  2383 usedir option -M or the "max-threads" setting in Proof General. A
  2384 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2385 to 6 on a 8-core machine.  User-code needs to observe certain
  2386 guidelines for thread-safe programming, see appendix A in the Isar
  2387 Implementation manual.
  2388 
  2389 
  2390 
  2391 New in Isabelle2005 (October 2005)
  2392 ----------------------------------
  2393 
  2394 *** General ***
  2395 
  2396 * Theory headers: the new header syntax for Isar theories is
  2397 
  2398   theory <name>
  2399   imports <theory1> ... <theoryN>
  2400   uses <file1> ... <fileM>
  2401   begin
  2402 
  2403 where the 'uses' part is optional.  The previous syntax
  2404 
  2405   theory <name> = <theory1> + ... + <theoryN>:
  2406 
  2407 will disappear in the next release.  Use isatool fixheaders to convert
  2408 existing theory files.  Note that there is no change in ancient
  2409 non-Isar theories now, but these will disappear soon.
  2410 
  2411 * Theory loader: parent theories can now also be referred to via
  2412 relative and absolute paths.
  2413 
  2414 * Command 'find_theorems' searches for a list of criteria instead of a
  2415 list of constants. Known criteria are: intro, elim, dest, name:string,
  2416 simp:term, and any term. Criteria can be preceded by '-' to select
  2417 theorems that do not match. Intro, elim, dest select theorems that
  2418 match the current goal, name:s selects theorems whose fully qualified
  2419 name contain s, and simp:term selects all simplification rules whose
  2420 lhs match term.  Any other term is interpreted as pattern and selects
  2421 all theorems matching the pattern. Available in ProofGeneral under
  2422 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2423 
  2424   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2425 
  2426 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2427 matching the current goal as introduction rule and not having "HOL."
  2428 in their name (i.e. not being defined in theory HOL).
  2429 
  2430 * Command 'thms_containing' has been discontinued in favour of
  2431 'find_theorems'; INCOMPATIBILITY.
  2432 
  2433 * Communication with Proof General is now 8bit clean, which means that
  2434 Unicode text in UTF-8 encoding may be used within theory texts (both
  2435 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2436 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2437 
  2438   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2439   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2440 
  2441 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2442 Classical Reasoner.  Typical big applications run around 2 times
  2443 faster.
  2444 
  2445 
  2446 *** Document preparation ***
  2447 
  2448 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2449 of raw sources.  Only those symbols that do not require additional
  2450 LaTeX packages (depending on comments in isabellesym.sty) are
  2451 displayed properly, everything else is left verbatim.  isatool display
  2452 and isatool print are used as front ends (these are subject to the
  2453 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2454 
  2455 * Command tags control specific markup of certain regions of text,
  2456 notably folding and hiding.  Predefined tags include "theory" (for
  2457 theory begin and end), "proof" for proof commands, and "ML" for
  2458 commands involving ML code; the additional tags "visible" and
  2459 "invisible" are unused by default.  Users may give explicit tag
  2460 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2461 interpretation of tags is determined by the LaTeX job during document
  2462 preparation: see option -V of isatool usedir, or options -n and -t of
  2463 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2464 \isadroptag.
  2465 
  2466 Several document versions may be produced at the same time via isatool
  2467 usedir (the generated index.html will link all of them).  Typical
  2468 specifications include ''-V document=theory,proof,ML'' to present
  2469 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2470 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2471 these parts without any formal replacement text.  The Isabelle site
  2472 default settings produce ''document'' and ''outline'' versions as
  2473 specified above.
  2474 
  2475 * Several new antiquotations:
  2476 
  2477   @{term_type term} prints a term with its type annotated;
  2478 
  2479   @{typeof term} prints the type of a term;
  2480 
  2481   @{const const} is the same as @{term const}, but checks that the
  2482   argument is a known logical constant;
  2483 
  2484   @{term_style style term} and @{thm_style style thm} print a term or
  2485   theorem applying a "style" to it
  2486 
  2487   @{ML text}
  2488 
  2489 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2490 definitions, equations, inequations etc., 'concl' printing only the
  2491 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2492 to print the specified premise.  TermStyle.add_style provides an ML
  2493 interface for introducing further styles.  See also the "LaTeX Sugar"
  2494 document practical applications.  The ML antiquotation prints
  2495 type-checked ML expressions verbatim.
  2496 
  2497 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2498 and 'text' support optional locale specification '(in loc)', which
  2499 specifies the default context for interpreting antiquotations.  For
  2500 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2501 
  2502 * Option 'locale=NAME' of antiquotations specifies an alternative
  2503 context interpreting the subsequent argument.  For example: @{thm
  2504 [locale=lattice] inf_assoc}.
  2505 
  2506 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2507 a proof context.
  2508 
  2509 * Proper output of antiquotations for theory commands involving a
  2510 proof context (such as 'locale' or 'theorem (in loc) ...').
  2511 
  2512 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2513 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2514 
  2515 * isatool usedir: new option -C (default true) controls whether option
  2516 -D should include a copy of the original document directory; -C false
  2517 prevents unwanted effects such as copying of administrative CVS data.
  2518 
  2519 
  2520 *** Pure ***
  2521 
  2522 * Considerably improved version of 'constdefs' command.  Now performs
  2523 automatic type-inference of declared constants; additional support for
  2524 local structure declarations (cf. locales and HOL records), see also
  2525 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2526 sequential dependencies of definitions within a single 'constdefs'
  2527 section; moreover, the declared name needs to be an identifier.  If
  2528 all fails, consider to fall back on 'consts' and 'defs' separately.
  2529 
  2530 * Improved indexed syntax and implicit structures.  First of all,
  2531 indexed syntax provides a notational device for subscripted
  2532 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2533 expressions.  Secondly, in a local context with structure
  2534 declarations, number indexes \<^sub>n or the empty index (default
  2535 number 1) refer to a certain fixed variable implicitly; option
  2536 show_structs controls printing of implicit structures.  Typical
  2537 applications of these concepts involve record types and locales.
  2538 
  2539 * New command 'no_syntax' removes grammar declarations (and
  2540 translations) resulting from the given syntax specification, which is
  2541 interpreted in the same manner as for the 'syntax' command.
  2542 
  2543 * 'Advanced' translation functions (parse_translation etc.) may depend
  2544 on the signature of the theory context being presently used for
  2545 parsing/printing, see also isar-ref manual.
  2546 
  2547 * Improved 'oracle' command provides a type-safe interface to turn an
  2548 ML expression of type theory -> T -> term into a primitive rule of
  2549 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2550 is already included here); see also FOL/ex/IffExample.thy;
  2551 INCOMPATIBILITY.
  2552 
  2553 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2554 before); "cI" is no longer bound, use "c.intro" instead.
  2555 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2556 axclasses vs. locales.
  2557 
  2558 * Improved internal renaming of symbolic identifiers -- attach primes
  2559 instead of base 26 numbers.
  2560 
  2561 * New flag show_question_marks controls printing of leading question
  2562 marks in schematic variable names.
  2563 
  2564 * In schematic variable names, *any* symbol following \<^isub> or
  2565 \<^isup> is now treated as part of the base name.  For example, the
  2566 following works without printing of awkward ".0" indexes:
  2567 
  2568   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2569     by simp
  2570 
  2571 * Inner syntax includes (*(*nested*) comments*).
  2572 
  2573 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2574 annotations as "(00...)".
  2575 
  2576 * Clear separation of logical types and nonterminals, where the latter
  2577 may only occur in 'syntax' specifications or type abbreviations.
  2578 Before that distinction was only partially implemented via type class
  2579 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2580 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2581 exotic syntax specifications may require further adaption
  2582 (e.g. Cube/Cube.thy).
  2583 
  2584 * Removed obsolete type class "logic", use the top sort {} instead.
  2585 Note that non-logical types should be declared as 'nonterminals'
  2586 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2587 specifications.
  2588 
  2589 * Attributes 'induct' and 'cases': type or set names may now be
  2590 locally fixed variables as well.
  2591 
  2592 * Simplifier: can now control the depth to which conditional rewriting
  2593 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2594 Limit.
  2595 
  2596 * Simplifier: simplification procedures may now take the current
  2597 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2598 interface), which is very useful for calling the Simplifier
  2599 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2600 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2601 low-level mk_simproc no longer applies Logic.varify internally, to
  2602 allow for use in a context of fixed variables.
  2603 
  2604 * thin_tac now works even if the assumption being deleted contains !!
  2605 or ==>.  More generally, erule now works even if the major premise of
  2606 the elimination rule contains !! or ==>.
  2607 
  2608 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2609 
  2610 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2611 from Pure, which contains all common declarations already.  Both
  2612 theories are defined via plain Isabelle/Isar .thy files.
  2613 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2614 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2615 use isatool fixcpure to adapt your theory and ML sources.
  2616 
  2617 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2618 selections of theorems in named facts via index ranges.
  2619 
  2620 * 'print_theorems': in theory mode, really print the difference
  2621 wrt. the last state (works for interactive theory development only),
  2622 in proof mode print all local facts (cf. 'print_facts');
  2623 
  2624 * 'hide': option '(open)' hides only base names.
  2625 
  2626 * More efficient treatment of intermediate checkpoints in interactive
  2627 theory development.
  2628 
  2629 * Code generator is now invoked via code_module (incremental code
  2630 generation) and code_library (modular code generation, ML structures
  2631 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2632 must be quoted when used as identifiers.
  2633 
  2634 * New 'value' command for reading, evaluating and printing terms using
  2635 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2636 quoted when used as identifier.
  2637 
  2638 
  2639 *** Locales ***
  2640 
  2641 * New commands for the interpretation of locale expressions in
  2642 theories (1), locales (2) and proof contexts (3).  These generate
  2643 proof obligations from the expression specification.  After the
  2644 obligations have been discharged, theorems of the expression are added
  2645 to the theory, target locale or proof context.  The synopsis of the
  2646 commands is a follows:
  2647 
  2648   (1) interpretation expr inst
  2649   (2) interpretation target < expr
  2650   (3) interpret expr inst
  2651 
  2652 Interpretation in theories and proof contexts require a parameter
  2653 instantiation of terms from the current context.  This is applied to
  2654 specifications and theorems of the interpreted expression.
  2655 Interpretation in locales only permits parameter renaming through the
  2656 locale expression.  Interpretation is smart in that interpretations
  2657 that are active already do not occur in proof obligations, neither are
  2658 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2659 inspect active interpretations of a particular locale.  For details,
  2660 see the Isar Reference manual.  Examples can be found in
  2661 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2662 
  2663 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2664 'interpret' instead.
  2665 
  2666 * New context element 'constrains' for adding type constraints to
  2667 parameters.
  2668 
  2669 * Context expressions: renaming of parameters with syntax
  2670 redeclaration.
  2671 
  2672 * Locale declaration: 'includes' disallowed.
  2673 
  2674 * Proper static binding of attribute syntax -- i.e. types / terms /
  2675 facts mentioned as arguments are always those of the locale definition
  2676 context, independently of the context of later invocations.  Moreover,
  2677 locale operations (renaming and type / term instantiation) are applied
  2678 to attribute arguments as expected.
  2679 
  2680 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2681 actual attributes; rare situations may require Attrib.attribute to
  2682 embed those attributes into Attrib.src that lack concrete syntax.
  2683 Attribute implementations need to cooperate properly with the static
  2684 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2685 Attrib.XXX_thm etc. already do the right thing without further
  2686 intervention.  Only unusual applications -- such as "where" or "of"
  2687 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2688 on the context and the facts involved -- may have to assign parsed
  2689 values to argument tokens explicitly.
  2690 
  2691 * Changed parameter management in theorem generation for long goal
  2692 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2693 theorem statement in rare situations.
  2694 
  2695 * Locale inspection command 'print_locale' omits notes elements.  Use
  2696 'print_locale!' to have them included in the output.
  2697 
  2698 
  2699 *** Provers ***
  2700 
  2701 * Provers/hypsubst.ML: improved version of the subst method, for
  2702 single-step rewriting: it now works in bound variable contexts. New is
  2703 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2704 rewrite a different subterm than the original subst method, which is
  2705 still available as 'simplesubst'.
  2706 
  2707 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2708 and quasi orders.
  2709 
  2710 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2711 reflexive-transitive closure of relations.
  2712 
  2713 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2714 limit (previously hard-coded with a value of 20) user-definable.
  2715 
  2716 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2717 is peformed already.  Object-logics merely need to finish their
  2718 initial simpset configuration as before.  INCOMPATIBILITY.
  2719 
  2720 
  2721 *** HOL ***
  2722 
  2723 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2724 
  2725   syntax (epsilon)
  2726     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2727 
  2728 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2729 and x-symbol; use option '-m epsilon' to get it actually printed.
  2730 Moreover, the mathematically important symbolic identifier \<epsilon>
  2731 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2732 
  2733 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2734 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2735 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2736 support corresponding Isar calculations.
  2737 
  2738 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2739 instead of ":".
  2740 
  2741 * theory SetInterval: changed the syntax for open intervals:
  2742 
  2743   Old       New
  2744   {..n(}    {..<n}
  2745   {)n..}    {n<..}
  2746   {m..n(}   {m..<n}
  2747   {)m..n}   {m<..n}
  2748   {)m..n(}  {m<..<n}
  2749 
  2750 The old syntax is still supported but will disappear in the next
  2751 release.  For conversion use the following Emacs search and replace
  2752 patterns (these are not perfect but work quite well):
  2753 
  2754   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2755   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2756 
  2757 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2758 equalities in commutative rings; method 'algebra' provides a generic
  2759 interface.
  2760 
  2761 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2762 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2763 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2764 be a tuple pattern.
  2765 
  2766 Some new syntax forms are available:
  2767 
  2768   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2769   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2770   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2771   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2772 
  2773 The latter form "\<Sum>x < k. e" used to be based on a separate
  2774 function "Summation", which has been discontinued.
  2775 
  2776 * theory Finite_Set: in structured induction proofs, the insert case
  2777 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2778 (insert F x)'.
  2779 
  2780 * The 'refute' command has been extended to support a much larger
  2781 fragment of HOL, including axiomatic type classes, constdefs and
  2782 typedefs, inductive datatypes and recursion.
  2783 
  2784 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2785 Requires zChaff with proof generation to be installed.  See
  2786 HOL/ex/SAT_Examples.thy for examples.
  2787 
  2788 * Datatype induction via method 'induct' now preserves the name of the
  2789 induction variable. For example, when proving P(xs::'a list) by
  2790 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2791 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2792 in unstructured proof scripts.
  2793 
  2794 * Reworked implementation of records.  Improved scalability for
  2795 records with many fields, avoiding performance problems for type
  2796 inference. Records are no longer composed of nested field types, but
  2797 of nested extension types. Therefore the record type only grows linear
  2798 in the number of extensions and not in the number of fields.  The
  2799 top-level (users) view on records is preserved.  Potential
  2800 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2801 old record representation. The type generated for a record is called
  2802 <record_name>_ext_type.
  2803 
  2804 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2805 proofs triggered by a record definition or a simproc (if
  2806 quick_and_dirty is enabled).  Definitions of large records can take
  2807 quite long.
  2808 
  2809 New simproc record_upd_simproc for simplification of multiple record
  2810 updates enabled by default.  Moreover, trivial updates are also
  2811 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2812 occasionally, since simplification is more powerful by default.
  2813 
  2814 * typedef: proper support for polymorphic sets, which contain extra
  2815 type-variables in the term.
  2816 
  2817 * Simplifier: automatically reasons about transitivity chains
  2818 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2819 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2820 old proofs break occasionally as simplification may now solve more
  2821 goals than previously.
  2822 
  2823 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2824 present.  Works for all partial orders (class "order"), in particular
  2825 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2826 just like y <= x.
  2827 
  2828 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2829 bound variable or a constant then the let is unfolded.  Otherwise
  2830 first a is simplified to b, and then f b is simplified to g. If
  2831 possible we abstract b from g arriving at "let x = b in h x",
  2832 otherwise we unfold the let and arrive at g.  The simproc can be
  2833 enabled/disabled by the reference use_let_simproc.  Potential
  2834 INCOMPATIBILITY since simplification is more powerful by default.
  2835 
  2836 * Classical reasoning: the meson method now accepts theorems as arguments.
  2837 
  2838 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2839 jobs to provide advice on the provability of subgoals.
  2840 
  2841 * Theory OrderedGroup and Ring_and_Field: various additions and
  2842 improvements to faciliate calculations involving equalities and
  2843 inequalities.
  2844 
  2845 The following theorems have been eliminated or modified
  2846 (INCOMPATIBILITY):
  2847 
  2848   abs_eq             now named abs_of_nonneg
  2849   abs_of_ge_0        now named abs_of_nonneg
  2850   abs_minus_eq       now named abs_of_nonpos
  2851   imp_abs_id         now named abs_of_nonneg
  2852   imp_abs_neg_id     now named abs_of_nonpos
  2853   mult_pos           now named mult_pos_pos
  2854   mult_pos_le        now named mult_nonneg_nonneg
  2855   mult_pos_neg_le    now named mult_nonneg_nonpos
  2856   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2857   mult_neg           now named mult_neg_neg
  2858   mult_neg_le        now named mult_nonpos_nonpos
  2859 
  2860 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2861      
  2862      zero_le_square
  2863      not_square_less_zero 
  2864 
  2865   The following lemmas have been deleted from Real/RealPow:
  2866   
  2867      realpow_zero_zero
  2868      realpow_two
  2869      realpow_less
  2870      zero_le_power
  2871      realpow_two_le
  2872      abs_realpow_two
  2873      realpow_two_abs     
  2874 
  2875 * Theory Parity: added rules for simplifying exponents.
  2876 
  2877 * Theory List:
  2878 
  2879 The following theorems have been eliminated or modified
  2880 (INCOMPATIBILITY):
  2881 
  2882   list_all_Nil       now named list_all.simps(1)
  2883   list_all_Cons      now named list_all.simps(2)
  2884   list_all_conv      now named list_all_iff
  2885   set_mem_eq         now named mem_iff
  2886 
  2887 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  2888 asymptotic "big O" calculations.  See the notes in BigO.thy.
  2889 
  2890 
  2891 *** HOL-Complex ***
  2892 
  2893 * Theory RealDef: better support for embedding natural numbers and
  2894 integers in the reals.
  2895 
  2896 The following theorems have been eliminated or modified
  2897 (INCOMPATIBILITY):
  2898 
  2899   exp_ge_add_one_self  now requires no hypotheses
  2900   real_of_int_add      reversed direction of equality (use [symmetric])
  2901   real_of_int_minus    reversed direction of equality (use [symmetric])
  2902   real_of_int_diff     reversed direction of equality (use [symmetric])
  2903   real_of_int_mult     reversed direction of equality (use [symmetric])
  2904 
  2905 * Theory RComplete: expanded support for floor and ceiling functions.
  2906 
  2907 * Theory Ln is new, with properties of the natural logarithm
  2908 
  2909 * Hyperreal: There is a new type constructor "star" for making
  2910 nonstandard types.  The old type names are now type synonyms:
  2911 
  2912   hypreal = real star
  2913   hypnat = nat star
  2914   hcomplex = complex star
  2915 
  2916 * Hyperreal: Many groups of similarly-defined constants have been
  2917 replaced by polymorphic versions (INCOMPATIBILITY):
  2918 
  2919   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2920 
  2921   starset      <-- starsetNat, starsetC
  2922   *s*          <-- *sNat*, *sc*
  2923   starset_n    <-- starsetNat_n, starsetC_n
  2924   *sn*         <-- *sNatn*, *scn*
  2925   InternalSets <-- InternalNatSets, InternalCSets
  2926 
  2927   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2928   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2929   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2930   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2931   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2932 
  2933 * Hyperreal: Many type-specific theorems have been removed in favor of
  2934 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2935 
  2936   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2937   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2938   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2939   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2940   right_minus <-- hypreal_add_minus
  2941   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2942   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2943   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2944   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2945   mult_1_right <-- hcomplex_mult_one_right
  2946   mult_zero_left <-- hcomplex_mult_zero_left
  2947   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2948   right_distrib <-- hypnat_add_mult_distrib2
  2949   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2950   right_inverse <-- hypreal_mult_inverse
  2951   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2952   order_refl <-- {hypreal,hypnat}_le_refl
  2953   order_trans <-- {hypreal,hypnat}_le_trans
  2954   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2955   order_less_le <-- {hypreal,hypnat}_less_le
  2956   linorder_linear <-- {hypreal,hypnat}_le_linear
  2957   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2958   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2959   add_nonneg_nonneg <-- hypreal_le_add_order
  2960 
  2961 * Hyperreal: Separate theorems having to do with type-specific
  2962 versions of constants have been merged into theorems that apply to the
  2963 new polymorphic constants (INCOMPATIBILITY):
  2964 
  2965   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2966   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2967   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2968   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2969   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2970   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2971   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2972   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2973   STAR_diff <-- {STAR,STARC}_diff
  2974   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2975     STARC_hcomplex_of_complex}_image_subset
  2976   starset_n_Un <-- starset{Nat,C}_n_Un
  2977   starset_n_Int <-- starset{Nat,C}_n_Int
  2978   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2979   starset_n_diff <-- starset{Nat,C}_n_diff
  2980   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2981   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2982   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2983   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2984   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2985   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2986   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2987   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2988   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2989   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2990   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2991   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2992   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2993   starfun_diff <-- starfun{C,RC,CR}_diff
  2994   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2995   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2996   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2997   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2998   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2999   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3000   starfun_Id <-- starfunC_Id
  3001   starfun_approx <-- starfun{Nat,CR}_approx
  3002   starfun_capprox <-- starfun{C,RC}_capprox
  3003   starfun_abs <-- starfunNat_rabs
  3004   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3005   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3006   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3007   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3008   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3009   starfun_add_approx <-- starfunCR_add_approx
  3010   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3011   starfun_divide <-- starfun{C,CR,RC}_divide
  3012   starfun_n <-- starfun{Nat,C}_n
  3013   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3014   starfun_n_add <-- starfun{Nat,C}_n_add
  3015   starfun_n_add_minus <-- starfunNat_n_add_minus
  3016   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3017   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3018   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3019 
  3020   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3021   star_n_minus <-- {hypreal,hcomplex}_minus
  3022   star_n_diff <-- {hypreal,hcomplex}_diff
  3023   star_n_mult <-- {hypreal,hcomplex}_mult
  3024   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3025   star_n_le <-- {hypreal,hypnat}_le
  3026   star_n_less <-- {hypreal,hypnat}_less
  3027   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3028   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3029   star_n_abs <-- hypreal_hrabs
  3030   star_n_divide <-- hcomplex_divide
  3031 
  3032   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3033   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3034   star_of_diff <-- hypreal_of_real_diff
  3035   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3036   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3037   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3038   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3039   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3040   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3041   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3042   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3043   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3044   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3045   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3046   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3047   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3048   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3049   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3050   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3051   star_of_power <-- hypreal_of_real_power
  3052   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3053 
  3054 * Hyperreal: new method "transfer" that implements the transfer
  3055 principle of nonstandard analysis. With a subgoal that mentions
  3056 nonstandard types like "'a star", the command "apply transfer"
  3057 replaces it with an equivalent one that mentions only standard types.
  3058 To be successful, all free variables must have standard types; non-
  3059 standard variables must have explicit universal quantifiers.
  3060 
  3061 * Hyperreal: A theory of Taylor series.
  3062 
  3063 
  3064 *** HOLCF ***
  3065 
  3066 * Discontinued special version of 'constdefs' (which used to support
  3067 continuous functions) in favor of the general Pure one with full
  3068 type-inference.
  3069 
  3070 * New simplification procedure for solving continuity conditions; it
  3071 is much faster on terms with many nested lambda abstractions (cubic
  3072 instead of exponential time).
  3073 
  3074 * New syntax for domain package: selector names are now optional.
  3075 Parentheses should be omitted unless argument is lazy, for example:
  3076 
  3077   domain 'a stream = cons "'a" (lazy "'a stream")
  3078 
  3079 * New command 'fixrec' for defining recursive functions with pattern
  3080 matching; defining multiple functions with mutual recursion is also
  3081 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3082 sinr, or any data constructor defined by the domain package. The given
  3083 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3084 syntax and examples.
  3085 
  3086 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3087 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3088 but the proof obligation additionally includes an admissibility
  3089 requirement. The packages generate instances of class cpo or pcpo,
  3090 with continuity and strictness theorems for Rep and Abs.
  3091 
  3092 * HOLCF: Many theorems have been renamed according to a more standard naming
  3093 scheme (INCOMPATIBILITY):
  3094 
  3095   foo_inject:  "foo$x = foo$y ==> x = y"
  3096   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3097   foo_less:    "(foo$x << foo$y) = (x << y)"
  3098   foo_strict:  "foo$UU = UU"
  3099   foo_defined: "... ==> foo$x ~= UU"
  3100   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3101 
  3102 
  3103 *** ZF ***
  3104 
  3105 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3106 including the First Isomorphism Theorem (on quotienting by the kernel
  3107 of a homomorphism).
  3108 
  3109 * ZF/Simplifier: install second copy of type solver that actually
  3110 makes use of TC rules declared to Isar proof contexts (or locales);
  3111 the old version is still required for ML proof scripts.
  3112 
  3113 
  3114 *** Cube ***
  3115 
  3116 * Converted to Isar theory format; use locales instead of axiomatic
  3117 theories.
  3118 
  3119 
  3120 *** ML ***
  3121 
  3122 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3123 for ||>, ||>>, |>>,
  3124 
  3125 * Pure/library.ML no longer defines its own option datatype, but uses
  3126 that of the SML basis, which has constructors NONE and SOME instead of
  3127 None and Some, as well as exception Option.Option instead of OPTION.
  3128 The functions the, if_none, is_some, is_none have been adapted
  3129 accordingly, while Option.map replaces apsome.
  3130 
  3131 * Pure/library.ML: the exception LIST has been given up in favour of
  3132 the standard exceptions Empty and Subscript, as well as
  3133 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3134 superceded by the standard hd and tl functions etc.
  3135 
  3136 A number of basic list functions are no longer exported to the ML
  3137 toplevel, as they are variants of predefined functions.  The following
  3138 suggests how one can translate existing code:
  3139 
  3140     rev_append xs ys = List.revAppend (xs, ys)
  3141     nth_elem (i, xs) = List.nth (xs, i)
  3142     last_elem xs = List.last xs
  3143     flat xss = List.concat xss
  3144     seq fs = List.app fs
  3145     partition P xs = List.partition P xs
  3146     mapfilter f xs = List.mapPartial f xs
  3147 
  3148 * Pure/library.ML: several combinators for linear functional
  3149 transformations, notably reverse application and composition:
  3150 
  3151   x |> f                f #> g
  3152   (x, y) |-> f          f #-> g
  3153 
  3154 * Pure/library.ML: introduced/changed precedence of infix operators:
  3155 
  3156   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3157   infix 2 ?;
  3158   infix 3 o oo ooo oooo;
  3159   infix 4 ~~ upto downto;
  3160 
  3161 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3162 infix operators.
  3163 
  3164 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3165 fold_map support linear functional transformations and nesting.  For
  3166 example:
  3167 
  3168   fold f [x1, ..., xN] y =
  3169     y |> f x1 |> ... |> f xN
  3170 
  3171   (fold o fold) f [xs1, ..., xsN] y =
  3172     y |> fold f xs1 |> ... |> fold f xsN
  3173 
  3174   fold f [x1, ..., xN] =
  3175     f x1 #> ... #> f xN
  3176 
  3177   (fold o fold) f [xs1, ..., xsN] =
  3178     fold f xs1 #> ... #> fold f xsN
  3179 
  3180 * Pure/library.ML: the following selectors on type 'a option are
  3181 available:
  3182 
  3183   the:               'a option -> 'a  (*partial*)
  3184   these:             'a option -> 'a  where 'a = 'b list
  3185   the_default: 'a -> 'a option -> 'a
  3186   the_list:          'a option -> 'a list
  3187 
  3188 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3189 basic operations for association lists, following natural argument
  3190 order; moreover the explicit equality predicate passed here avoids
  3191 potentially expensive polymorphic runtime equality checks.
  3192 The old functions may be expressed as follows:
  3193 
  3194   assoc = uncurry (AList.lookup (op =))
  3195   assocs = these oo AList.lookup (op =)
  3196   overwrite = uncurry (AList.update (op =)) o swap
  3197 
  3198 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3199 
  3200   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3201   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3202 
  3203 replacing make_keylist and keyfilter (occassionally used)
  3204 Naive rewrites:
  3205 
  3206   make_keylist = AList.make
  3207   keyfilter = AList.find (op =)
  3208 
  3209 * eq_fst and eq_snd now take explicit equality parameter, thus
  3210   avoiding eqtypes. Naive rewrites:
  3211 
  3212     eq_fst = eq_fst (op =)
  3213     eq_snd = eq_snd (op =)
  3214 
  3215 * Removed deprecated apl and apr (rarely used).
  3216   Naive rewrites:
  3217 
  3218     apl (n, op) =>>= curry op n
  3219     apr (op, m) =>>= fn n => op (n, m)
  3220 
  3221 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3222 provides a reasonably efficient light-weight implementation of sets as
  3223 lists.
  3224 
  3225 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3226 few new operations; existing lookup and update are now curried to
  3227 follow natural argument order (for use with fold etc.);
  3228 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3229 
  3230 * Pure/General: output via the Isabelle channels of
  3231 writeln/warning/error etc. is now passed through Output.output, with a
  3232 hook for arbitrary transformations depending on the print_mode
  3233 (cf. Output.add_mode -- the first active mode that provides a output
  3234 function wins).  Already formatted output may be embedded into further
  3235 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3236 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3237 accommodate easy composition of diagnostic messages etc.  Programmers
  3238 rarely need to care about Output.output or Output.raw at all, with
  3239 some notable exceptions: Output.output is required when bypassing the
  3240 standard channels (writeln etc.), or in token translations to produce
  3241 properly formatted results; Output.raw is required when capturing
  3242 already output material that will eventually be presented to the user
  3243 a second time.  For the default print mode, both Output.output and
  3244 Output.raw have no effect.
  3245 
  3246 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3247 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3248 cumulative results are displayed at the end of a batch session.
  3249 
  3250 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3251 replaced by File.platform_path and File.shell_path (with appropriate
  3252 hooks).  This provides a clean interface for unusual systems where the
  3253 internal and external process view of file names are different.
  3254 
  3255 * Pure: more efficient orders for basic syntactic entities: added
  3256 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3257 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3258 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3259 orders now -- potential INCOMPATIBILITY for code that depends on a
  3260 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3261 Library.sort_strings on result).
  3262 
  3263 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3264 fold_types traverse types/terms from left to right, observing natural
  3265 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3266 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3267 
  3268 * Pure: name spaces have been refined, with significant changes of the
  3269 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3270 to extern(_table).  The plain name entry path is superceded by a
  3271 general 'naming' context, which also includes the 'policy' to produce
  3272 a fully qualified name and external accesses of a fully qualified
  3273 name; NameSpace.extend is superceded by context dependent
  3274 Sign.declare_name.  Several theory and proof context operations modify
  3275 the naming context.  Especially note Theory.restore_naming and
  3276 ProofContext.restore_naming to get back to a sane state; note that
  3277 Theory.add_path is no longer sufficient to recover from
  3278 Theory.absolute_path in particular.
  3279 
  3280 * Pure: new flags short_names (default false) and unique_names
  3281 (default true) for controlling output of qualified names.  If
  3282 short_names is set, names are printed unqualified.  If unique_names is
  3283 reset, the name prefix is reduced to the minimum required to achieve
  3284 the original result when interning again, even if there is an overlap
  3285 with earlier declarations.
  3286 
  3287 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3288 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3289 (useful for printing error messages).  INCOMPATIBILITY.
  3290 
  3291 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3292 Theory.theory are now identified, referring to the universal
  3293 Context.theory (see Pure/context.ML).  Actual signature and theory
  3294 content is managed as theory data.  The old code and interfaces were
  3295 spread over many files and structures; the new arrangement introduces
  3296 considerable INCOMPATIBILITY to gain more clarity:
  3297 
  3298   Context -- theory management operations (name, identity, inclusion,
  3299     parents, ancestors, merge, etc.), plus generic theory data;
  3300 
  3301   Sign -- logical signature and syntax operations (declaring consts,
  3302     types, etc.), plus certify/read for common entities;
  3303 
  3304   Theory -- logical theory operations (stating axioms, definitions,
  3305     oracles), plus a copy of logical signature operations (consts,
  3306     types, etc.); also a few basic management operations (Theory.copy,
  3307     Theory.merge, etc.)
  3308 
  3309 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3310 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3311 for convenience -- they merely return the theory.
  3312 
  3313 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3314 
  3315 * Pure: the Isar proof context type is already defined early in Pure
  3316 as Context.proof (note that ProofContext.context and Proof.context are
  3317 aliases, where the latter is the preferred name).  This enables other
  3318 Isabelle components to refer to that type even before Isar is present.
  3319 
  3320 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3321 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3322 any of these kinds.  For example, Sign.intern typeK is now
  3323 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3324 Theory.hide_types.  Also note that former
  3325 Theory.hide_classes/types/consts are now
  3326 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3327 internalize their arguments!  INCOMPATIBILITY.
  3328 
  3329 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3330 datatype thmref (with constructors Name and NameSelection) instead of
  3331 plain string -- INCOMPATIBILITY;
  3332 
  3333 * Pure: cases produced by proof methods specify options, where NONE
  3334 means to remove case bindings -- INCOMPATIBILITY in
  3335 (RAW_)METHOD_CASES.
  3336 
  3337 * Pure: the following operations retrieve axioms or theorems from a
  3338 theory node or theory hierarchy, respectively:
  3339 
  3340   Theory.axioms_of: theory -> (string * term) list
  3341   Theory.all_axioms_of: theory -> (string * term) list
  3342   PureThy.thms_of: theory -> (string * thm) list
  3343   PureThy.all_thms_of: theory -> (string * thm) list
  3344 
  3345 * Pure: print_tac now outputs the goal through the trace channel.
  3346 
  3347 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3348 Reference Toplevel.debug (default false) controls detailed printing
  3349 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3350 controls execution profiling -- set to 1 for time and 2 for space
  3351 (both increase the runtime).
  3352 
  3353 * Isar session: The initial use of ROOT.ML is now always timed,
  3354 i.e. the log will show the actual process times, in contrast to the
  3355 elapsed wall-clock time that the outer shell wrapper produces.
  3356 
  3357 * Simplifier: improved handling of bound variables (nameless
  3358 representation, avoid allocating new strings).  Simprocs that invoke
  3359 the Simplifier recursively should use Simplifier.inherit_bounds to
  3360 avoid local name clashes.  Failure to do so produces warnings
  3361 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3362 for further details.
  3363 
  3364 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3365 bindings for all theorems stored within a given theory; this may help
  3366 in porting non-Isar theories to Isar ones, while keeping ML proof
  3367 scripts for the time being.
  3368 
  3369 * ML operator HTML.with_charset specifies the charset begin used for
  3370 generated HTML files.  For example:
  3371 
  3372   HTML.with_charset "utf-8" use_thy "Hebrew";
  3373   HTML.with_charset "utf-8" use_thy "Chinese";
  3374 
  3375 
  3376 *** System ***
  3377 
  3378 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3379 isabelle, isatool etc.).
  3380 
  3381 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3382 isatool doc, isatool mkdir, display_drafts etc.).
  3383 
  3384 * isatool usedir: option -f allows specification of the ML file to be
  3385 used by Isabelle; default is ROOT.ML.
  3386 
  3387 * New isatool version outputs the version identifier of the Isabelle
  3388 distribution being used.
  3389 
  3390 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3391 (containing Boolean satisfiability problems) into Isabelle/HOL
  3392 theories.
  3393 
  3394 
  3395 
  3396 New in Isabelle2004 (April 2004)
  3397 --------------------------------
  3398 
  3399 *** General ***
  3400 
  3401 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3402   Replaces linorder.ML.
  3403 
  3404 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3405   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3406   (\<a>...\<z>), are now considered normal letters, and can therefore
  3407   be used anywhere where an ASCII letter (a...zA...Z) has until
  3408   now. COMPATIBILITY: This obviously changes the parsing of some
  3409   terms, especially where a symbol has been used as a binder, say
  3410   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3411   as an identifier.  Fix it by inserting a space around former
  3412   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3413   existing theory and ML files.
  3414 
  3415 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3416 
  3417 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3418   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3419   a normal (but invisible) letter. For multiple letter subscripts repeat
  3420   \<^isub> like this: x\<^isub>1\<^isub>2.
  3421 
  3422 * Pure: There are now sub-/superscripts that can span more than one
  3423   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3424   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3425   superscript. The new control characters are not identifier parts.
  3426 
  3427 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3428   content of "..." to the latex file instead of \isacntrl... . The "..."
  3429   may consist of any printable characters excluding the end bracket >.
  3430 
  3431 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3432   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3433   declare constants "final", which prevents their being given a definition
  3434   later.  It is useful for constants whose behaviour is fixed axiomatically
  3435   rather than definitionally, such as the meta-logic connectives.
  3436 
  3437 * Pure: 'instance' now handles general arities with general sorts
  3438   (i.e. intersections of classes),
  3439 
  3440 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3441   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3442   It can be changed to alter the colors/layout of generated pages.
  3443 
  3444 
  3445 *** Isar ***
  3446 
  3447 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3448   cut_tac, subgoal_tac and thin_tac:
  3449   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3450     locales are no longer forced to write Isar proof scripts.
  3451     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3452     emulations.
  3453   - INCOMPATIBILITY: names of variables to be instantiated may no
  3454     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3455     This is consistent with the instantiation attribute "where".
  3456 
  3457 * Attributes "where" and "of":
  3458   - Now take type variables of instantiated theorem into account when reading
  3459     the instantiation string.  This fixes a bug that caused instantiated
  3460     theorems to have too special types in some circumstances.
  3461   - "where" permits explicit instantiations of type variables.
  3462 
  3463 * Calculation commands "moreover" and "also" no longer interfere with
  3464   current facts ("this"), admitting arbitrary combinations with "then"
  3465   and derived forms.
  3466 
  3467 * Locales:
  3468   - Goal statements involving the context element "includes" no longer
  3469     generate theorems with internal delta predicates (those ending on
  3470     "_axioms") in the premise.
  3471     Resolve particular premise with <locale>.intro to obtain old form.
  3472   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3473     specification and "includes" elements in goal statement.
  3474   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3475     [intro?] and [elim?] (respectively) by default.
  3476   - Experimental command for instantiation of locales in proof contexts:
  3477         instantiate <label>[<attrs>]: <loc>
  3478     Instantiates locale <loc> and adds all its theorems to the current context
  3479     taking into account their attributes.  Label and attrs are optional
  3480     modifiers, like in theorem declarations.  If present, names of
  3481     instantiated theorems are qualified with <label>, and the attributes
  3482     <attrs> are applied after any attributes these theorems might have already.
  3483       If the locale has assumptions, a chained fact of the form
  3484     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3485     are derived.  The command does not support old-style locales declared
  3486     with "locale (open)".
  3487       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3488 
  3489 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3490   (Isar) contexts.
  3491 
  3492 
  3493 *** HOL ***
  3494 
  3495 * Proof import: new image HOL4 contains the imported library from
  3496   the HOL4 system with about 2500 theorems. It is imported by
  3497   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3498   can be used like any other Isabelle image.  See
  3499   HOL/Import/HOL/README for more information.
  3500 
  3501 * Simplifier:
  3502   - Much improved handling of linear and partial orders.
  3503     Reasoners for linear and partial orders are set up for type classes
  3504     "linorder" and "order" respectively, and are added to the default simpset
  3505     as solvers.  This means that the simplifier can build transitivity chains
  3506     to solve goals from the assumptions.
  3507   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3508     of blast or auto after simplification become unnecessary because the goal
  3509     is solved by simplification already.
  3510 
  3511 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3512     all proved in axiomatic type classes for semirings, rings and fields.
  3513 
  3514 * Numerics:
  3515   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3516     now formalized using the Ring_and_Field theory mentioned above.
  3517   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3518     than before, because now they are set up once in a generic manner.
  3519   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3520     Look for the general versions in Ring_and_Field (and Power if they concern
  3521     exponentiation).
  3522 
  3523 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3524 
  3525 * Records:
  3526   - Record types are now by default printed with their type abbreviation
  3527     instead of the list of all field types. This can be configured via
  3528     the reference "print_record_type_abbr".
  3529   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3530     (not enabled by default).
  3531   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3532     EX x. x = sel r to True (not enabled by default).
  3533   - Tactic "record_split_simp_tac" to split and simplify records added.
  3534 
  3535 * 'specification' command added, allowing for definition by
  3536   specification.  There is also an 'ax_specification' command that
  3537   introduces the new constants axiomatically.
  3538 
  3539 * arith(_tac) is now able to generate counterexamples for reals as well.
  3540 
  3541 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3542 
  3543 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3544   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3545 
  3546 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3547   matrix theory to linear programming.
  3548 
  3549 * Unions and Intersections:
  3550   The latex output syntax of UN and INT has been changed
  3551   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3552   i.e. the index formulae has become a subscript.
  3553   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3554 
  3555 * Unions and Intersections over Intervals:
  3556   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3557   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3558   like in normal math, and corresponding versions for < and for intersection.
  3559 
  3560 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3561   lexicographic dictonary ordering has been added as "lexord".
  3562 
  3563 * ML: the legacy theory structures Int and List have been removed. They had
  3564   conflicted with ML Basis Library structures having the same names.
  3565 
  3566 * 'refute' command added to search for (finite) countermodels.  Only works
  3567   for a fragment of HOL.  The installation of an external SAT solver is
  3568   highly recommended.  See "HOL/Refute.thy" for details.
  3569 
  3570 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3571   formulae under an assignment of free variables to random values.
  3572   In contrast to 'refute', it can deal with inductive datatypes,
  3573   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3574   for examples.
  3575 
  3576 
  3577 *** HOLCF ***
  3578 
  3579 * Streams now come with concatenation and are part of the HOLCF image
  3580 
  3581 
  3582 
  3583 New in Isabelle2003 (May 2003)
  3584 ------------------------------
  3585 
  3586 *** General ***
  3587 
  3588 * Provers/simplifier:
  3589 
  3590   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3591     Assumptions are now subject to complete mutual simplification,
  3592     not just from left to right. The simplifier now preserves
  3593     the order of assumptions.
  3594 
  3595     Potential INCOMPATIBILITY:
  3596 
  3597     -- simp sometimes diverges where the old version did
  3598        not, e.g. invoking simp on the goal
  3599 
  3600         [| P (f x); y = x; f x = f y |] ==> Q
  3601 
  3602        now gives rise to the infinite reduction sequence
  3603 
  3604         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3605 
  3606        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3607        kind of problem.
  3608 
  3609     -- Tactics combining classical reasoner and simplification (such as auto)
  3610        are also affected by this change, because many of them rely on
  3611        simp. They may sometimes diverge as well or yield a different numbers
  3612        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3613        in case of problems. Sometimes subsequent calls to the classical
  3614        reasoner will fail because a preceeding call to the simplifier too
  3615        eagerly simplified the goal, e.g. deleted redundant premises.
  3616 
  3617   - The simplifier trace now shows the names of the applied rewrite rules
  3618 
  3619   - You can limit the number of recursive invocations of the simplifier
  3620     during conditional rewriting (where the simplifie tries to solve the
  3621     conditions before applying the rewrite rule):
  3622     ML "simp_depth_limit := n"
  3623     where n is an integer. Thus you can force termination where previously
  3624     the simplifier would diverge.
  3625 
  3626   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3627 
  3628   - No longer aborts on failed congruence proof.  Instead, the
  3629     congruence is ignored.
  3630 
  3631 * Pure: New generic framework for extracting programs from constructive
  3632   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3633   as HOL/Extraction for some case studies.
  3634 
  3635 * Pure: The main goal of the proof state is no longer shown by default, only
  3636 the subgoals. This behaviour is controlled by a new flag.
  3637    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3638 (ML: Proof.show_main_goal).
  3639 
  3640 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3641 rules whose conclusion matches subgoal 1:
  3642       PG menu: Isabelle/Isar -> Show me -> matching rules
  3643 The rules are ordered by how closely they match the subgoal.
  3644 In particular, rules that solve a subgoal outright are displayed first
  3645 (or rather last, the way they are printed).
  3646 (ML: ProofGeneral.print_intros())
  3647 
  3648 * Pure: New flag trace_unify_fail causes unification to print
  3649 diagnostic information (PG: in trace buffer) when it fails. This is
  3650 useful for figuring out why single step proofs like rule, erule or
  3651 assumption failed.
  3652 
  3653 * Pure: Locale specifications now produce predicate definitions
  3654 according to the body of text (covering assumptions modulo local
  3655 definitions); predicate "loc_axioms" covers newly introduced text,
  3656 while "loc" is cumulative wrt. all included locale expressions; the
  3657 latter view is presented only on export into the global theory
  3658 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3659 on the old view without predicates;
  3660 
  3661 * Pure: predefined locales "var" and "struct" are useful for sharing
  3662 parameters (as in CASL, for example); just specify something like
  3663 ``var x + var y + struct M'' as import;
  3664 
  3665 * Pure: improved thms_containing: proper indexing of facts instead of
  3666 raw theorems; check validity of results wrt. current name space;
  3667 include local facts of proof configuration (also covers active
  3668 locales), cover fixed variables in index; may use "_" in term
  3669 specification; an optional limit for the number of printed facts may
  3670 be given (the default is 40);
  3671 
  3672 * Pure: disallow duplicate fact bindings within new-style theory files
  3673 (batch-mode only);
  3674 
  3675 * Provers: improved induct method: assumptions introduced by case
  3676 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3677 the goal statement); "foo" still refers to all facts collectively;
  3678 
  3679 * Provers: the function blast.overloaded has been removed: all constants
  3680 are regarded as potentially overloaded, which improves robustness in exchange
  3681 for slight decrease in efficiency;
  3682 
  3683 * Provers/linorder: New generic prover for transitivity reasoning over
  3684 linear orders.  Note: this prover is not efficient!
  3685 
  3686 * Isar: preview of problems to finish 'show' now produce an error
  3687 rather than just a warning (in interactive mode);
  3688 
  3689 
  3690 *** HOL ***
  3691 
  3692 * arith(_tac)
  3693 
  3694  - Produces a counter example if it cannot prove a goal.
  3695    Note that the counter example may be spurious if the goal is not a formula
  3696    of quantifier-free linear arithmetic.
  3697    In ProofGeneral the counter example appears in the trace buffer.
  3698 
  3699  - Knows about div k and mod k where k is a numeral of type nat or int.
  3700 
  3701  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3702    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3703    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3704 
  3705 * simp's arithmetic capabilities have been enhanced a bit: it now
  3706 takes ~= in premises into account (by performing a case split);
  3707 
  3708 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3709 are distributed over a sum of terms;
  3710 
  3711 * New tactic "trans_tac" and method "trans" instantiate
  3712 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3713 "<=", "<" and "=").
  3714 
  3715 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3716 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3717 
  3718 * 'typedef' command has new option "open" to suppress the set
  3719 definition;
  3720 
  3721 * functions Min and Max on finite sets have been introduced (theory
  3722 Finite_Set);
  3723 
  3724 * attribute [symmetric] now works for relations as well; it turns
  3725 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3726 
  3727 * induct over a !!-quantified statement (say !!x1..xn):
  3728   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3729 
  3730 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3731 %x. None. Warning: empty_def now refers to the previously hidden definition
  3732 of the empty set.
  3733 
  3734 * Algebra: formalization of classical algebra.  Intended as base for
  3735 any algebraic development in Isabelle.  Currently covers group theory
  3736 (up to Sylow's theorem) and ring theory (Universal Property of
  3737 Univariate Polynomials).  Contributions welcome;
  3738 
  3739 * GroupTheory: deleted, since its material has been moved to Algebra;
  3740 
  3741 * Complex: new directory of the complex numbers with numeric constants,
  3742 nonstandard complex numbers, and some complex analysis, standard and
  3743 nonstandard (Jacques Fleuriot);
  3744 
  3745 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3746 
  3747 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3748 Fleuriot);
  3749 
  3750 * Real/HahnBanach: updated and adapted to locales;
  3751 
  3752 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3753 Gray and Kramer);
  3754 
  3755 * UNITY: added the Meier-Sanders theory of progress sets;
  3756 
  3757 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3758 as abstract algorithms, instantiated to the JVM;
  3759 
  3760 * Bali: Java source language formalization. Type system, operational
  3761 semantics, axiomatic semantics. Supported language features:
  3762 classes, interfaces, objects,virtual methods, static methods,
  3763 static/instance fields, arrays, access modifiers, definite
  3764 assignment, exceptions.
  3765 
  3766 
  3767 *** ZF ***
  3768 
  3769 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3770 universe, etc.);
  3771 
  3772 * Main ZF: virtually all theories converted to new-style format;
  3773 
  3774 
  3775 *** ML ***
  3776 
  3777 * Pure: Tactic.prove provides sane interface for internal proofs;
  3778 omits the infamous "standard" operation, so this is more appropriate
  3779 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3780 
  3781 * Pure: improved error reporting of simprocs;
  3782 
  3783 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3784 up simprocs;
  3785 
  3786 
  3787 *** Document preparation ***
  3788 
  3789 * uses \par instead of \\ for line breaks in theory text. This may
  3790 shift some page breaks in large documents. To get the old behaviour
  3791 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3792 
  3793 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3794 other packages
  3795 
  3796 * \<euro> now needs package babel/greek instead of marvosym (which
  3797 broke \Rightarrow)
  3798 
  3799 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3800 textcomp package)
  3801 
  3802 
  3803 
  3804 New in Isabelle2002 (March 2002)
  3805 --------------------------------
  3806 
  3807 *** Document preparation ***
  3808 
  3809 * greatly simplified document preparation setup, including more
  3810 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3811 instructive isatool mkdir; users should basically be able to get
  3812 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3813 users may run a separate document processing stage manually like this:
  3814 "isatool usedir -D output HOL Test && isatool document Test/output";
  3815 
  3816 * theory dependency graph may now be incorporated into documents;
  3817 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3818 with \includegraphics of LaTeX;
  3819 
  3820 * proper spacing of consecutive markup elements, especially text
  3821 blocks after section headings;
  3822 
  3823 * support bold style (for single symbols only), input syntax is like
  3824 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3825 
  3826 * \<bullet> is now output as bold \cdot by default, which looks much
  3827 better in printed text;
  3828 
  3829 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3830 note that these symbols are currently unavailable in Proof General /
  3831 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3832 
  3833 * isatool latex no longer depends on changed TEXINPUTS, instead
  3834 isatool document copies the Isabelle style files to the target
  3835 location;
  3836 
  3837 
  3838 *** Isar ***
  3839 
  3840 * Pure/Provers: improved proof by cases and induction;
  3841   - 'case' command admits impromptu naming of parameters (such as
  3842     "case (Suc n)");
  3843   - 'induct' method divinates rule instantiation from the inductive
  3844     claim; no longer requires excessive ?P bindings for proper
  3845     instantiation of cases;
  3846   - 'induct' method properly enumerates all possibilities of set/type
  3847     rules; as a consequence facts may be also passed through *type*
  3848     rules without further ado;
  3849   - 'induct' method now derives symbolic cases from the *rulified*
  3850     rule (before it used to rulify cases stemming from the internal
  3851     atomized version); this means that the context of a non-atomic
  3852     statement becomes is included in the hypothesis, avoiding the
  3853     slightly cumbersome show "PROP ?case" form;
  3854   - 'induct' may now use elim-style induction rules without chaining
  3855     facts, using ``missing'' premises from the goal state; this allows
  3856     rules stemming from inductive sets to be applied in unstructured
  3857     scripts, while still benefitting from proper handling of non-atomic
  3858     statements; NB: major inductive premises need to be put first, all
  3859     the rest of the goal is passed through the induction;
  3860   - 'induct' proper support for mutual induction involving non-atomic
  3861     rule statements (uses the new concept of simultaneous goals, see
  3862     below);
  3863   - append all possible rule selections, but only use the first
  3864     success (no backtracking);
  3865   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3866   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3867   - added 'print_induct_rules' (covered by help item in recent Proof
  3868     General versions);
  3869   - moved induct/cases attributes to Pure, methods to Provers;
  3870   - generic method setup instantiated for FOL and HOL;
  3871 
  3872 * Pure: support multiple simultaneous goal statements, for example
  3873 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3874 meta-level mechanism, this acts as if several individual goals had
  3875 been stated separately; in particular common proof methods need to be
  3876 repeated in order to cover all claims; note that a single elimination
  3877 step is *not* sufficient to establish the two conjunctions, so this
  3878 fails:
  3879 
  3880   assume "A & B" then have A and B ..   (*".." fails*)
  3881 
  3882 better use "obtain" in situations as above; alternative refer to
  3883 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  3884 
  3885 * Pure: proper integration with ``locales''; unlike the original
  3886 version by Florian Kammller, Isar locales package high-level proof
  3887 contexts rather than raw logical ones (e.g. we admit to include
  3888 attributes everywhere); operations on locales include merge and
  3889 rename; support for implicit arguments (``structures''); simultaneous
  3890 type-inference over imports and text; see also HOL/ex/Locales.thy for
  3891 some examples;
  3892 
  3893 * Pure: the following commands have been ``localized'', supporting a
  3894 target locale specification "(in name)": 'lemma', 'theorem',
  3895 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  3896 stored both within the locale and at the theory level (exported and
  3897 qualified by the locale name);
  3898 
  3899 * Pure: theory goals may now be specified in ``long'' form, with
  3900 ad-hoc contexts consisting of arbitrary locale elements. for example
  3901 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  3902 definitions may be given, too); the result is a meta-level rule with
  3903 the context elements being discharged in the obvious way;
  3904 
  3905 * Pure: new proof command 'using' allows to augment currently used
  3906 facts after a goal statement ('using' is syntactically analogous to
  3907 'apply', but acts on the goal's facts only); this allows chained facts
  3908 to be separated into parts given before and after a claim, as in
  3909 ``from a and b have C using d and e <proof>'';
  3910 
  3911 * Pure: renamed "antecedent" case to "rule_context";
  3912 
  3913 * Pure: new 'judgment' command records explicit information about the
  3914 object-logic embedding (used by several tools internally); no longer
  3915 use hard-wired "Trueprop";
  3916 
  3917 * Pure: added 'corollary' command;
  3918 
  3919 * Pure: fixed 'token_translation' command;
  3920 
  3921 * Pure: removed obsolete 'exported' attribute;
  3922 
  3923 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3924 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3925 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3926 
  3927 * Pure: method 'atomize' presents local goal premises as object-level
  3928 statements (atomic meta-level propositions); setup controlled via
  3929 rewrite rules declarations of 'atomize' attribute; example
  3930 application: 'induct' method with proper rule statements in improper
  3931 proof *scripts*;
  3932 
  3933 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3934 now consider the syntactic context of assumptions, giving a better
  3935 chance to get type-inference of the arguments right (this is
  3936 especially important for locales);
  3937 
  3938 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3939 mode;
  3940 
  3941 * Pure/obtain: the formal conclusion "thesis", being marked as
  3942 ``internal'', may no longer be reference directly in the text;
  3943 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3944 situations;
  3945 
  3946 * Pure: generic 'sym' attribute which declares a rule both as pure
  3947 'elim?' and for the 'symmetric' operation;
  3948 
  3949 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3950 text; the fixed correlation with particular command syntax has been
  3951 discontinued;
  3952 
  3953 * Pure: new method 'rules' is particularly well-suited for proof
  3954 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3955 but often produces more compact proof terms with less detours;
  3956 
  3957 * Pure/Provers/classical: simplified integration with pure rule
  3958 attributes and methods; the classical "intro?/elim?/dest?"
  3959 declarations coincide with the pure ones; the "rule" method no longer
  3960 includes classically swapped intros; "intro" and "elim" methods no
  3961 longer pick rules from the context; also got rid of ML declarations
  3962 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3963 INCOMPATIBILITY;
  3964 
  3965 * Provers/classical: attribute 'swapped' produces classical inversions
  3966 of introduction rules;
  3967 
  3968 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3969 rules instead of full simplifier context; 'iff' attribute handles
  3970 conditional rules;
  3971 
  3972 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3973 
  3974 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3975 "(permissive)" option to recover old behavior;
  3976 
  3977 * HOL: 'inductive' no longer features separate (collective) attributes
  3978 for 'intros' (was found too confusing);
  3979 
  3980 * HOL: properly declared induction rules less_induct and
  3981 wf_induct_rule;
  3982 
  3983 
  3984 *** HOL ***
  3985 
  3986 * HOL: moved over to sane numeral syntax; the new policy is as
  3987 follows:
  3988 
  3989   - 0 and 1 are polymorphic constants, which are defined on any
  3990   numeric type (nat, int, real etc.);
  3991 
  3992   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3993   binary representation internally;
  3994 
  3995   - type nat has special constructor Suc, and generally prefers Suc 0
  3996   over 1::nat and Suc (Suc 0) over 2::nat;
  3997 
  3998 This change may cause significant problems of INCOMPATIBILITY; here
  3999 are some hints on converting existing sources:
  4000 
  4001   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4002   entities, so expressions involving "-" (unary or binary minus) need
  4003   to be spaced properly;
  4004 
  4005   - existing occurrences of "1" may need to be constraint "1::nat" or
  4006   even replaced by Suc 0; similar for old "2";
  4007 
  4008   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4009 
  4010   - remove all special provisions on numerals in proofs;
  4011 
  4012 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4013 representation (depends on bin_arith_simps in the default context);
  4014 
  4015 * HOL: symbolic syntax for x^2 (numeral 2);
  4016 
  4017 * HOL: the class of all HOL types is now called "type" rather than
  4018 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4019 in axclass/classes, instance/arities, and (usually rare) occurrences
  4020 in typings (of consts etc.); internally the class is called
  4021 "HOL.type", ML programs should refer to HOLogic.typeS;
  4022 
  4023 * HOL/record package improvements:
  4024   - new derived operations "fields" to build a partial record section,
  4025     "extend" to promote a fixed record to a record scheme, and
  4026     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4027     declared as simp by default;
  4028   - shared operations ("more", "fields", etc.) now need to be always
  4029     qualified) --- potential INCOMPATIBILITY;
  4030   - removed "make_scheme" operations (use "make" with "extend") --
  4031     INCOMPATIBILITY;
  4032   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4033   - provides cases/induct rules for use with corresponding Isar
  4034     methods (for concrete records, record schemes, concrete more
  4035     parts, and schematic more parts -- in that order);
  4036   - internal definitions directly based on a light-weight abstract
  4037     theory of product types over typedef rather than datatype;
  4038 
  4039 * HOL: generic code generator for generating executable ML code from
  4040 specifications; specific support for HOL constructs such as inductive
  4041 datatypes and sets, as well as recursive functions; can be invoked
  4042 via 'generate_code' theory section;
  4043 
  4044 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4045 
  4046 * HOL: consolidated and renamed several theories.  In particular:
  4047         Ord.thy has been absorbed into HOL.thy
  4048         String.thy has been absorbed into List.thy
  4049 
  4050 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4051 (beware of argument permutation!);
  4052 
  4053 * HOL: linorder_less_split superseded by linorder_cases;
  4054 
  4055 * HOL/List: "nodups" renamed to "distinct";
  4056 
  4057 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4058 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4059   - Ex_def has changed, now need to use some_eq_ex
  4060 
  4061 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4062 in this (rare) case use:
  4063 
  4064   delSWrapper "split_all_tac"
  4065   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4066 
  4067 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4068 MAY FAIL;
  4069 
  4070 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4071 Isabelle's type classes, ^ on functions and relations has too general
  4072 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4073 necessary to attach explicit type constraints;
  4074 
  4075 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4076 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4077 renamed accordingly (eg "compI" -> "rel_compI").
  4078 
  4079 * HOL: syntax translations now work properly with numerals and records
  4080 expressions;
  4081 
  4082 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4083 of "lam" -- INCOMPATIBILITY;
  4084 
  4085 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4086 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4087 renamed "Product_Type.unit";
  4088 
  4089 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4090 
  4091 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4092 the "cases" method);
  4093 
  4094 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4095 Florian Kammller);
  4096 
  4097 * HOL/IMP: updated and converted to new-style theory format; several
  4098 parts turned into readable document, with proper Isar proof texts and
  4099 some explanations (by Gerwin Klein);
  4100 
  4101 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4102 
  4103 * HOL-Hyperreal is now a logic image;
  4104 
  4105 
  4106 *** HOLCF ***
  4107 
  4108 * Isar: consts/constdefs supports mixfix syntax for continuous
  4109 operations;
  4110 
  4111 * Isar: domain package adapted to new-style theory format, e.g. see
  4112 HOLCF/ex/Dnat.thy;
  4113 
  4114 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4115 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4116 lift.induct_tac, always use UU instead of Undef;
  4117 
  4118 * HOLCF/IMP: updated and converted to new-style theory;
  4119 
  4120 
  4121 *** ZF ***
  4122 
  4123 * Isar: proper integration of logic-specific tools and packages,
  4124 including theory commands '(co)inductive', '(co)datatype',
  4125 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4126 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4127 
  4128 * theory Main no longer includes AC; for the Axiom of Choice, base
  4129 your theory on Main_ZFC;
  4130 
  4131 * the integer library now covers quotients and remainders, with many
  4132 laws relating division to addition, multiplication, etc.;
  4133 
  4134 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4135 typeless version of the formalism;
  4136 
  4137 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4138 format;
  4139 
  4140 * ZF/Induct: new directory for examples of inductive definitions,
  4141 including theory Multiset for multiset orderings; converted to
  4142 new-style theory format;
  4143 
  4144 * ZF: many new theorems about lists, ordinals, etc.;
  4145 
  4146 
  4147 *** General ***
  4148 
  4149 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4150 variable proof controls level of detail: 0 = no proofs (only oracle
  4151 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4152 also ref manual for further ML interfaces;
  4153 
  4154 * Pure/axclass: removed obsolete ML interface
  4155 goal_subclass/goal_arity;
  4156 
  4157 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4158 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4159 separate tokens, so expressions involving minus need to be spaced
  4160 properly;
  4161 
  4162 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4163 rather than "infixl" or "infixr";
  4164 
  4165 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4166 sort constraint specifications in type inference; e.g. "x::_::foo"
  4167 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4168 type variable);
  4169 
  4170 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4171 control output of nested => (types); the default behavior is
  4172 "type_brackets";
  4173 
  4174 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4175 tokens into AST constants;
  4176 
  4177 * Pure/syntax: prefer later declarations of translations and print
  4178 translation functions; potential INCOMPATIBILITY: need to reverse
  4179 multiple declarations for same syntax element constant;
  4180 
  4181 * Pure/show_hyps reset by default (in accordance to existing Isar
  4182 practice);
  4183 
  4184 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4185 addSafter;
  4186 
  4187 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4188 as well;
  4189 
  4190 * system: tested support for MacOS X; should be able to get Isabelle +
  4191 Proof General to work in a plain Terminal after installing Poly/ML
  4192 (e.g. from the Isabelle distribution area) and GNU bash alone
  4193 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4194 support requires further installations, e.g. from
  4195 http://fink.sourceforge.net/);
  4196 
  4197 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4198 
  4199 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4200 of 40 MB), cf. ML_OPTIONS;
  4201 
  4202 * system: Proof General keywords specification is now part of the
  4203 Isabelle distribution (see etc/isar-keywords.el);
  4204 
  4205 * system: support for persistent Proof General sessions (refrain from
  4206 outdating all loaded theories on startup); user may create writable
  4207 logic images like this: ``isabelle -q HOL Test'';
  4208 
  4209 * system: smart selection of Isabelle process versus Isabelle
  4210 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4211 run both "isabelle" and "Isabelle" even if file names are badly
  4212 damaged (executable inspects the case of the first letter of its own
  4213 name); added separate "isabelle-process" and "isabelle-interface";
  4214 
  4215 * system: refrain from any attempt at filtering input streams; no
  4216 longer support ``8bit'' encoding of old isabelle font, instead proper
  4217 iso-latin characters may now be used; the related isatools
  4218 "symbolinput" and "nonascii" have disappeared as well;
  4219 
  4220 * system: removed old "xterm" interface (the print modes "xterm" and
  4221 "xterm_color" are still available for direct use in a suitable
  4222 terminal);
  4223 
  4224 
  4225 
  4226 New in Isabelle99-2 (February 2001)
  4227 -----------------------------------
  4228 
  4229 *** Overview of INCOMPATIBILITIES ***
  4230 
  4231 * HOL: please note that theories in the Library and elsewhere often use the
  4232 new-style (Isar) format; to refer to their theorems in an ML script you must
  4233 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4234 
  4235 * HOL: inductive package no longer splits induction rule aggressively,
  4236 but only as far as specified by the introductions given; the old
  4237 format may be recovered via ML function complete_split_rule or attribute
  4238 'split_rule (complete)';
  4239 
  4240 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4241 gfp_Tarski to gfp_unfold;
  4242 
  4243 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4244 
  4245 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4246 relation); infix "^^" has been renamed "``"; infix "``" has been
  4247 renamed "`"; "univalent" has been renamed "single_valued";
  4248 
  4249 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4250 operation;
  4251 
  4252 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4253 
  4254 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4255 
  4256 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4257 consequence, it is no longer monotonic wrt. the local goal context
  4258 (which is now passed through the inductive cases);
  4259 
  4260 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4261 \<gg> to \<ggreater>;
  4262 
  4263 
  4264 *** Document preparation ***
  4265 
  4266 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4267 available: are "it" for near math-mode best-style output, "sl" for
  4268 slanted text style, and "tt" for plain type-writer; if no
  4269 \isabellestyle command is given, output is according to slanted
  4270 type-writer);
  4271 
  4272 * support sub/super scripts (for single symbols only), input syntax is
  4273 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4274 
  4275 * some more standard symbols; see Appendix A of the system manual for
  4276 the complete list of symbols defined in isabellesym.sty;
  4277 
  4278 * improved isabelle style files; more abstract symbol implementation
  4279 (should now use \isamath{...} and \isatext{...} in custom symbol
  4280 definitions);
  4281 
  4282 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4283 state; Note that presentation of goal states does not conform to
  4284 actual human-readable proof documents.  Please do not include goal
  4285 states into document output unless you really know what you are doing!
  4286 
  4287 * proper indentation of antiquoted output with proportional LaTeX
  4288 fonts;
  4289 
  4290 * no_document ML operator temporarily disables LaTeX document
  4291 generation;
  4292 
  4293 * isatool unsymbolize tunes sources for plain ASCII communication;
  4294 
  4295 
  4296 *** Isar ***
  4297 
  4298 * Pure: Isar now suffers initial goal statements to contain unbound
  4299 schematic variables (this does not conform to actual readable proof
  4300 documents, due to unpredictable outcome and non-compositional proof
  4301 checking); users who know what they are doing may use schematic goals
  4302 for Prolog-style synthesis of proven results;
  4303 
  4304 * Pure: assumption method (an implicit finishing) now handles actual
  4305 rules as well;
  4306 
  4307 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4308 initial goal, declare "that" only as Pure intro (only for single
  4309 steps); the "that" rule assumption may now be involved in implicit
  4310 finishing, thus ".." becomes a feasible for trivial obtains;
  4311 
  4312 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4313 instance proofs may be performed by "..";
  4314 
  4315 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4316 statements as well;
  4317 
  4318 * Pure: more robust selection of calculational rules;
  4319 
  4320 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4321 rule (as well as the assumption rule);
  4322 
  4323 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4324 lemmas, using the graph browser tool;
  4325 
  4326 * Pure: predict failure of "show" in interactive mode;
  4327 
  4328 * Pure: 'thms_containing' now takes actual terms as arguments;
  4329 
  4330 * HOL: improved method 'induct' --- now handles non-atomic goals
  4331 (potential INCOMPATIBILITY); tuned error handling;
  4332 
  4333 * HOL: cases and induct rules now provide explicit hints about the
  4334 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4335 any remaining facts are inserted into the goal verbatim;
  4336 
  4337 * HOL: local contexts (aka cases) may now contain term bindings as
  4338 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4339 the result to be shown in each case;
  4340 
  4341 * HOL: added 'recdef_tc' command;
  4342 
  4343 * isatool convert assists in eliminating legacy ML scripts;
  4344 
  4345 
  4346 *** HOL ***
  4347 
  4348 * HOL/Library: a collection of generic theories to be used together
  4349 with main HOL; the theory loader path already includes this directory
  4350 by default; the following existing theories have been moved here:
  4351 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4352 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4353 
  4354 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4355 modelling and verification task performed in Isabelle/HOL +
  4356 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4357 
  4358 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4359 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4360 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4361 'domain', this makes the theory consistent with mathematical
  4362 literature;
  4363 
  4364 * HOL basics: added overloaded operations "inverse" and "divide"
  4365 (infix "/"), syntax for generic "abs" operation, generic summation
  4366 operator \<Sum>;
  4367 
  4368 * HOL/typedef: simplified package, provide more useful rules (see also
  4369 HOL/subset.thy);
  4370 
  4371 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4372 now expressed as a proper nested rule (old-style tactic scripts may
  4373 require atomize_strip_tac to cope with non-atomic premises);
  4374 
  4375 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4376 to "split_conv" (old name still available for compatibility);
  4377 
  4378 * HOL: improved concrete syntax for strings (e.g. allows translation
  4379 rules with string literals);
  4380 
  4381 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4382  and Fleuriot's mechanization of analysis, including the transcendental
  4383  functions for the reals;
  4384 
  4385 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4386 
  4387 
  4388 *** CTT ***
  4389 
  4390 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4391 "lam" is displayed as TWO lambda-symbols
  4392 
  4393 * CTT: theory Main now available, containing everything (that is, Bool
  4394 and Arith);
  4395 
  4396 
  4397 *** General ***
  4398 
  4399 * Pure: the Simplifier has been implemented properly as a derived rule
  4400 outside of the actual kernel (at last!); the overall performance
  4401 penalty in practical applications is about 50%, while reliability of
  4402 the Isabelle inference kernel has been greatly improved;
  4403 
  4404 * print modes "brackets" and "no_brackets" control output of nested =>
  4405 (types) and ==> (props); the default behaviour is "brackets";
  4406 
  4407 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4408 as assumptions as well;
  4409 
  4410 * system: support Poly/ML 4.0;
  4411 
  4412 * system: isatool install handles KDE version 1 or 2;
  4413 
  4414 
  4415 
  4416 New in Isabelle99-1 (October 2000)
  4417 ----------------------------------
  4418 
  4419 *** Overview of INCOMPATIBILITIES ***
  4420 
  4421 * HOL: simplification of natural numbers is much changed; to partly
  4422 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4423 issue the following ML commands:
  4424 
  4425   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4426   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4427 
  4428 * HOL: simplification no longer dives into case-expressions; this is
  4429 controlled by "t.weak_case_cong" for each datatype t;
  4430 
  4431 * HOL: nat_less_induct renamed to less_induct;
  4432 
  4433 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4434 fixsome to patch .thy and .ML sources automatically;
  4435 
  4436   select_equality  -> some_equality
  4437   select_eq_Ex     -> some_eq_ex
  4438   selectI2EX       -> someI2_ex
  4439   selectI2         -> someI2
  4440   selectI          -> someI
  4441   select1_equality -> some1_equality
  4442   Eps_sym_eq       -> some_sym_eq_trivial
  4443   Eps_eq           -> some_eq_trivial
  4444 
  4445 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4446 
  4447 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4448 instead);
  4449 
  4450 * HOL: the recursion equations generated by 'recdef' are now called
  4451 f.simps instead of f.rules;
  4452 
  4453 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4454 
  4455 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4456 sometimes be needed;
  4457 
  4458 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4459 
  4460 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4461 
  4462 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4463 product is now "<*>" instead of "Times"; the lexicographic product is
  4464 now "<*lex*>" instead of "**";
  4465 
  4466 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4467 of main HOL, but was unused); better use HOL's datatype package;
  4468 
  4469 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4470 the old syntax may be recovered as follows:
  4471 
  4472   syntax (symbols)
  4473     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4474       (infixl "\\<oplus>" 100)
  4475 
  4476 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4477 
  4478 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4479 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4480 internally;
  4481 
  4482 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4483 changed from A/r to A//r;
  4484 
  4485 * ZF: new treatment of arithmetic (nat & int) may break some old
  4486 proofs;
  4487 
  4488 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4489 rulify -> rule_format, elimify -> elim_format, ...);
  4490 
  4491 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4492 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4493 should have to change intro!! to intro? only); replaced "delrule" by
  4494 "rule del";
  4495 
  4496 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4497 
  4498 * Provers: strengthened force_tac by using new first_best_tac;
  4499 
  4500 * LaTeX document preparation: several changes of isabelle.sty (see
  4501 lib/texinputs);
  4502 
  4503 
  4504 *** Document preparation ***
  4505 
  4506 * formal comments (text blocks etc.) in new-style theories may now
  4507 contain antiquotations of thm/prop/term/typ/text to be presented
  4508 according to latex print mode; concrete syntax is like this:
  4509 @{term[show_types] "f(x) = a + x"};
  4510 
  4511 * isatool mkdir provides easy setup of Isabelle session directories,
  4512 including proper document sources;
  4513 
  4514 * generated LaTeX sources are now deleted after successful run
  4515 (isatool document -c); may retain a copy somewhere else via -D option
  4516 of isatool usedir;
  4517 
  4518 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4519 style files, achieving self-contained LaTeX sources and simplifying
  4520 LaTeX debugging;
  4521 
  4522 * old-style theories now produce (crude) LaTeX output as well;
  4523 
  4524 * browser info session directories are now self-contained (may be put
  4525 on WWW server seperately); improved graphs of nested sessions; removed
  4526 graph for 'all sessions';
  4527 
  4528 * several improvements in isabelle style files; \isabellestyle{it}
  4529 produces fake math mode output; \isamarkupheader is now \section by
  4530 default; see lib/texinputs/isabelle.sty etc.;
  4531 
  4532 
  4533 *** Isar ***
  4534 
  4535 * Isar/Pure: local results and corresponding term bindings are now
  4536 subject to Hindley-Milner polymorphism (similar to ML); this
  4537 accommodates incremental type-inference very nicely;
  4538 
  4539 * Isar/Pure: new derived language element 'obtain' supports
  4540 generalized existence reasoning;
  4541 
  4542 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4543 support accumulation of results, without applying any rules yet;
  4544 useful to collect intermediate results without explicit name
  4545 references, and for use with transitivity rules with more than 2
  4546 premises;
  4547 
  4548 * Isar/Pure: scalable support for case-analysis type proofs: new
  4549 'case' language element refers to local contexts symbolically, as
  4550 produced by certain proof methods; internally, case names are attached
  4551 to theorems as "tags";
  4552 
  4553 * Isar/Pure: theory command 'hide' removes declarations from
  4554 class/type/const name spaces;
  4555 
  4556 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4557 indicate potential overloading;
  4558 
  4559 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4560 
  4561 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4562 "{a,b,c}" instead of {a,b,c};
  4563 
  4564 * Isar/Pure now provides its own version of intro/elim/dest
  4565 attributes; useful for building new logics, but beware of confusion
  4566 with the version in Provers/classical;
  4567 
  4568 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4569 case name 'antecedent';
  4570 
  4571 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4572 to the current context is now done automatically);
  4573 
  4574 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4575 for definining proof methods in ML;
  4576 
  4577 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4578 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4579 most cases, one should have to change intro!! to intro? only);
  4580 replaced "delrule" by "rule del";
  4581 
  4582 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4583 'symmetric' attribute (the latter supercedes [RS sym]);
  4584 
  4585 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4586 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4587 well (including splits);
  4588 
  4589 * Isar/Provers: Simplifier and Classical methods now support all kind
  4590 of modifiers used in the past, including 'cong', 'iff', etc.
  4591 
  4592 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4593 of Simplifier and Classical reasoner);
  4594 
  4595 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4596 now support named cases; major packages (inductive, datatype, primrec,
  4597 recdef) support case names and properly name parameters;
  4598 
  4599 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4600 monotonicity conditions are extracted to be proven at end of
  4601 calculations;
  4602 
  4603 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4604 method anyway;
  4605 
  4606 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4607 split_if split_if_asm; datatype package provides theorems foo.splits =
  4608 foo.split foo.split_asm for each datatype;
  4609 
  4610 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4611 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4612 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4613 use "(cases (simplified))" method in proper proof texts);
  4614 
  4615 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4616 
  4617 * Isar: names of theorems etc. may be natural numbers as well;
  4618 
  4619 * Isar: 'pr' command: optional arguments for goals_limit and
  4620 ProofContext.prems_limit; no longer prints theory contexts, but only
  4621 proof states;
  4622 
  4623 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4624 additional print modes to be specified; e.g. "pr(latex)" will print
  4625 proof state according to the Isabelle LaTeX style;
  4626 
  4627 * Isar: improved support for emulating tactic scripts, including proof
  4628 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4629 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4630 (for HOL datatypes);
  4631 
  4632 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4633 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4634 'proof method scripts' have to be in depth-first order;
  4635 
  4636 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4637 
  4638 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4639 should instead use individual commands for printing items
  4640 (print_commands, print_methods etc.);
  4641 
  4642 * Isar: added 'nothing' --- the empty list of theorems;
  4643 
  4644 
  4645 *** HOL ***
  4646 
  4647 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4648 corresponding virtual machine and a specification of its bytecode
  4649 verifier and a lightweight bytecode verifier, including proofs of
  4650 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4651 Cornelia Pusch (see also the homepage of project Bali at
  4652 http://isabelle.in.tum.de/Bali/);
  4653 
  4654 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4655 Clemens Ballarin;
  4656 
  4657 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4658 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4659 Rasmussen;
  4660 
  4661 * HOL/Lattice: fundamental concepts of lattice theory and order
  4662 structures, including duals, properties of bounds versus algebraic
  4663 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4664 Theorem for complete lattices etc.; may also serve as a demonstration
  4665 for abstract algebraic reasoning using axiomatic type classes, and
  4666 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4667 
  4668 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4669 von Oheimb;
  4670 
  4671 * HOL/IMPP: extension of IMP with local variables and mutually
  4672 recursive procedures, by David von Oheimb;
  4673 
  4674 * HOL/Lambda: converted into new-style theory and document;
  4675 
  4676 * HOL/ex/Multiquote: example of multiple nested quotations and
  4677 anti-quotations -- basically a generalized version of de-Bruijn
  4678 representation; very useful in avoiding lifting of operations;
  4679 
  4680 * HOL/record: added general record equality rule to simpset; fixed
  4681 select-update simplification procedure to handle extended records as
  4682 well; admit "r" as field name;
  4683 
  4684 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4685 other numeric types and also as the identity of groups, rings, etc.;
  4686 
  4687 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4688 Types nat and int belong to this axclass;
  4689 
  4690 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4691    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4692    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4693   two terms #m*u and #n*u are replaced by #(m+n)*u
  4694     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4695   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4696     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4697 
  4698 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4699 powerful prover for predicate logic but knows nothing of clasets; see
  4700 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4701 
  4702 * HOL: new version of "case_tac" subsumes both boolean case split and
  4703 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4704 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4705 
  4706 * HOL: simplification no longer dives into case-expressions: only the
  4707 selector expression is simplified, but not the remaining arms; to
  4708 enable full simplification of case-expressions for datatype t, you may
  4709 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4710 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4711 
  4712 * HOL/recdef: the recursion equations generated by 'recdef' for
  4713 function 'f' are now called f.simps instead of f.rules; if all
  4714 termination conditions are proved automatically, these simplification
  4715 rules are added to the simpset, as in primrec; rules may be named
  4716 individually as well, resulting in a separate list of theorems for
  4717 each equation;
  4718 
  4719 * HOL/While is a new theory that provides a while-combinator. It
  4720 permits the definition of tail-recursive functions without the
  4721 provision of a termination measure. The latter is necessary once the
  4722 invariant proof rule for while is applied.
  4723 
  4724 * HOL: new (overloaded) notation for the set of elements below/above
  4725 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4726 
  4727 * HOL: theorems impI, allI, ballI bound as "strip";
  4728 
  4729 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4730 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4731 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4732 
  4733 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4734 
  4735 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4736 main HOL, but was unused);
  4737 
  4738 * HOL: fewer consts declared as global (e.g. have to refer to
  4739 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4740 
  4741 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4742 in case of overlap with user translations (e.g. judgements over
  4743 tuples); (note that the underlying logical represenation is still
  4744 bogus);
  4745 
  4746 
  4747 *** ZF ***
  4748 
  4749 * ZF: simplification automatically cancels common terms in arithmetic
  4750 expressions over nat and int;
  4751 
  4752 * ZF: new treatment of nat to minimize type-checking: all operators
  4753 coerce their operands to a natural number using the function natify,
  4754 making the algebraic laws unconditional;
  4755 
  4756 * ZF: as above, for int: operators coerce their operands to an integer
  4757 using the function intify;
  4758 
  4759 * ZF: the integer library now contains many of the usual laws for the
  4760 orderings, including $<=, and monotonicity laws for $+ and $*;
  4761 
  4762 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4763 simplification;
  4764 
  4765 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4766 to the simplifier and classical reasoner simultaneously;
  4767 
  4768 
  4769 *** General ***
  4770 
  4771 * Provers: blast_tac now handles actual object-logic rules as
  4772 assumptions; note that auto_tac uses blast_tac internally as well;
  4773 
  4774 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4775 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4776 
  4777 * Provers: delrules now handles destruct rules as well (no longer need
  4778 explicit make_elim);
  4779 
  4780 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4781   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4782 use instead the strong form,
  4783   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4784 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4785 from destruct-rules;
  4786 
  4787 * Provers: Simplifier.easy_setup provides a fast path to basic
  4788 Simplifier setup for new object-logics;
  4789 
  4790 * Pure: AST translation rules no longer require constant head on LHS;
  4791 
  4792 * Pure: improved name spaces: ambiguous output is qualified; support
  4793 for hiding of names;
  4794 
  4795 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4796 XSYMBOL_HOME; no longer need to do manual configuration in most
  4797 situations;
  4798 
  4799 * system: compression of ML heaps images may now be controlled via -c
  4800 option of isabelle and isatool usedir (currently only observed by
  4801 Poly/ML);
  4802 
  4803 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4804 useful for remote X11);
  4805 
  4806 * system: provide TAGS file for Isabelle sources;
  4807 
  4808 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4809 order;
  4810 
  4811 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4812 timing flag supersedes proof_timing and Toplevel.trace;
  4813 
  4814 * ML: new combinators |>> and |>>> for incremental transformations
  4815 with secondary results (e.g. certain theory extensions):
  4816 
  4817 * ML: PureThy.add_defs gets additional argument to indicate potential
  4818 overloading (usually false);
  4819 
  4820 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4821 results;
  4822 
  4823 
  4824 
  4825 New in Isabelle99 (October 1999)
  4826 --------------------------------
  4827 
  4828 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4829 
  4830 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4831 are no longer simplified.  (This allows the simplifier to unfold recursive
  4832 functional programs.)  To restore the old behaviour, declare
  4833 
  4834     Delcongs [if_weak_cong];
  4835 
  4836 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4837 complement;
  4838 
  4839 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4840 
  4841 * HOL/datatype: mutual_induct_tac no longer exists --
  4842   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  4843 
  4844 * HOL/typedef: fixed type inference for representing set; type
  4845 arguments now have to occur explicitly on the rhs as type constraints;
  4846 
  4847 * ZF: The con_defs part of an inductive definition may no longer refer
  4848 to constants declared in the same theory;
  4849 
  4850 * HOL, ZF: the function mk_cases, generated by the inductive
  4851 definition package, has lost an argument.  To simplify its result, it
  4852 uses the default simpset instead of a supplied list of theorems.
  4853 
  4854 * HOL/List: the constructors of type list are now Nil and Cons;
  4855 
  4856 * Simplifier: the type of the infix ML functions
  4857         setSSolver addSSolver setSolver addSolver
  4858 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4859 for packaging solvers. A solver is created via
  4860         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4861 where the string argument is only a comment.
  4862 
  4863 
  4864 *** Proof tools ***
  4865 
  4866 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4867 decision procedure for linear arithmetic. Currently it is used for
  4868 types `nat', `int', and `real' in HOL (see below); it can, should and
  4869 will be instantiated for other types and logics as well.
  4870 
  4871 * The simplifier now accepts rewrite rules with flexible heads, eg
  4872      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4873   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4874   matching.
  4875 
  4876 
  4877 *** General ***
  4878 
  4879 * New Isabelle/Isar subsystem provides an alternative to traditional
  4880 tactical theorem proving; together with the ProofGeneral/isar user
  4881 interface it offers an interactive environment for developing human
  4882 readable proof documents (Isar == Intelligible semi-automated
  4883 reasoning); for further information see isatool doc isar-ref,
  4884 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  4885 
  4886 * improved and simplified presentation of theories: better HTML markup
  4887 (including colors), graph views in several sizes; isatool usedir now
  4888 provides a proper interface for user theories (via -P option); actual
  4889 document preparation based on (PDF)LaTeX is available as well (for
  4890 new-style theories only); see isatool doc system for more information;
  4891 
  4892 * native support for Proof General, both for classic Isabelle and
  4893 Isabelle/Isar;
  4894 
  4895 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  4896 using the graph browser tool;
  4897 
  4898 * Isabelle manuals now also available as PDF;
  4899 
  4900 * theory loader rewritten from scratch (may not be fully
  4901 bug-compatible); old loadpath variable has been replaced by show_path,
  4902 add_path, del_path, reset_path functions; new operations such as
  4903 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  4904 isatool doc ref);
  4905 
  4906 * improved isatool install: option -k creates KDE application icon,
  4907 option -p DIR installs standalone binaries;
  4908 
  4909 * added ML_PLATFORM setting (useful for cross-platform installations);
  4910 more robust handling of platform specific ML images for SML/NJ;
  4911 
  4912 * the settings environment is now statically scoped, i.e. it is never
  4913 created again in sub-processes invoked from isabelle, isatool, or
  4914 Isabelle;
  4915 
  4916 * path element specification '~~' refers to '$ISABELLE_HOME';
  4917 
  4918 * in locales, the "assumes" and "defines" parts may be omitted if
  4919 empty;
  4920 
  4921 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4922 long arrows);
  4923 
  4924 * new print_mode "HTML";
  4925 
  4926 * new flag show_tags controls display of tags of theorems (which are
  4927 basically just comments that may be attached by some tools);
  4928 
  4929 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4930 mode and goal output format:
  4931 
  4932 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4933 244c244
  4934 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4935 ---
  4936 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4937 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4938 181c181
  4939 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4940 ---
  4941 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4942 
  4943 * function bind_thms stores lists of theorems (cf. bind_thm);
  4944 
  4945 * new shorthand tactics ftac, eatac, datac, fatac;
  4946 
  4947 * qed (and friends) now accept "" as result name; in that case the
  4948 theorem is not stored, but proper checks and presentation of the
  4949 result still apply;
  4950 
  4951 * theorem database now also indexes constants "Trueprop", "all",
  4952 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4953 
  4954 
  4955 *** HOL ***
  4956 
  4957 ** HOL arithmetic **
  4958 
  4959 * There are now decision procedures for linear arithmetic over nat and
  4960 int:
  4961 
  4962 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4963 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4964 are treated as atomic; subformulae not involving type `nat' or `int'
  4965 are ignored; quantified subformulae are ignored unless they are
  4966 positive universal or negative existential. The tactic has to be
  4967 invoked by hand and can be a little bit slow. In particular, the
  4968 running time is exponential in the number of occurrences of `min' and
  4969 `max', and `-' on `nat'.
  4970 
  4971 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4972 (negated) (in)equalities among the premises and the conclusion into
  4973 account (i.e. no compound formulae) and does not know about `min' and
  4974 `max', and `-' on `nat'. It is fast and is used automatically by the
  4975 simplifier.
  4976 
  4977 NB: At the moment, these decision procedures do not cope with mixed
  4978 nat/int formulae where the two parts interact, such as `m < n ==>
  4979 int(m) < int(n)'.
  4980 
  4981 * HOL/Numeral provides a generic theory of numerals (encoded
  4982 efficiently as bit strings); setup for types nat/int/real is in place;
  4983 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4984 int, existing theories and proof scripts may require a few additional
  4985 type constraints;
  4986 
  4987 * integer division and remainder can now be performed on constant
  4988 arguments;
  4989 
  4990 * many properties of integer multiplication, division and remainder
  4991 are now available;
  4992 
  4993 * An interface to the Stanford Validity Checker (SVC) is available through the
  4994 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4995 are proved automatically.  SVC must be installed separately, and its results
  4996 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4997 invocation of the underlying oracle).  For SVC see
  4998   http://verify.stanford.edu/SVC
  4999 
  5000 * IsaMakefile: the HOL-Real target now builds an actual image;
  5001 
  5002 
  5003 ** HOL misc **
  5004 
  5005 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5006 (in Isabelle/Isar) -- by Gertrud Bauer;
  5007 
  5008 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5009 analysis for assembly languages with subtypes;
  5010 
  5011 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5012 -- avoids syntactic ambiguities and treats state, transition, and
  5013 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5014 changed syntax and (many) tactics;
  5015 
  5016 * HOL/inductive: Now also handles more general introduction rules such
  5017   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5018   theorems are now maintained within the theory (maintained via the
  5019   "mono" attribute);
  5020 
  5021 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5022   (using function types) such as
  5023 
  5024   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5025 
  5026 * HOL/record: record_simproc (part of the default simpset) takes care
  5027 of selectors applied to updated records; record_split_tac is no longer
  5028 part of the default claset; update_defs may now be removed from the
  5029 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5030 
  5031   claset_ref () := claset() addSWrapper record_split_wrapper;
  5032   Delsimprocs [record_simproc]
  5033 
  5034 * HOL/typedef: fixed type inference for representing set; type
  5035 arguments now have to occur explicitly on the rhs as type constraints;
  5036 
  5037 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5038 names rather than an ML expression;
  5039 
  5040 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5041 supplied later.  Program schemes can be defined, such as
  5042     "While B C s = (if B s then While B C (C s) else s)"
  5043 where the well-founded relation can be chosen after B and C have been given.
  5044 
  5045 * HOL/List: the constructors of type list are now Nil and Cons;
  5046 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5047 course, ML tools referring to List.list.op # etc. have to be adapted;
  5048 
  5049 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5050 disabled by default; run isabelle with option -m HOL to get back to
  5051 the original Gordon/HOL-style output;
  5052 
  5053 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5054 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5055 
  5056 * HOL basic syntax simplified (more orthogonal): all variants of
  5057 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5058 Eps operator is provided as well: "SOME x. P[x]";
  5059 
  5060 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5061 
  5062 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5063 thus available for user theories;
  5064 
  5065 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5066 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5067 time;
  5068 
  5069 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5070 several times and then mp;
  5071 
  5072 
  5073 *** LK ***
  5074 
  5075 * the notation <<...>> is now available as a notation for sequences of
  5076 formulas;
  5077 
  5078 * the simplifier is now installed
  5079 
  5080 * the axiom system has been generalized (thanks to Soren Heilmann)
  5081 
  5082 * the classical reasoner now has a default rule database
  5083 
  5084 
  5085 *** ZF ***
  5086 
  5087 * new primrec section allows primitive recursive functions to be given
  5088 directly (as in HOL) over datatypes and the natural numbers;
  5089 
  5090 * new tactics induct_tac and exhaust_tac for induction (or case
  5091 analysis) over datatypes and the natural numbers;
  5092 
  5093 * the datatype declaration of type T now defines the recursor T_rec;
  5094 
  5095 * simplification automatically does freeness reasoning for datatype
  5096 constructors;
  5097 
  5098 * automatic type-inference, with AddTCs command to insert new
  5099 type-checking rules;
  5100 
  5101 * datatype introduction rules are now added as Safe Introduction rules
  5102 to the claset;
  5103 
  5104 * the syntax "if P then x else y" is now available in addition to
  5105 if(P,x,y);
  5106 
  5107 
  5108 *** Internal programming interfaces ***
  5109 
  5110 * tuned simplifier trace output; new flag debug_simp;
  5111 
  5112 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5113 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5114 
  5115 * AxClass.axclass_tac lost the theory argument;
  5116 
  5117 * tuned current_goals_markers semantics: begin / end goal avoids
  5118 printing empty lines;
  5119 
  5120 * removed prs and prs_fn hook, which was broken because it did not
  5121 include \n in its semantics, forcing writeln to add one
  5122 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5123 string -> unit if you really want to output text without newline;
  5124 
  5125 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5126 plain output, interface builders may have to enable 'isabelle_font'
  5127 mode to get Isabelle font glyphs as before;
  5128 
  5129 * refined token_translation interface; INCOMPATIBILITY: output length
  5130 now of type real instead of int;
  5131 
  5132 * theory loader actions may be traced via new ThyInfo.add_hook
  5133 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5134 your own database of information attached to *whole* theories -- as
  5135 opposed to intra-theory data slots offered via TheoryDataFun;
  5136 
  5137 * proper handling of dangling sort hypotheses (at last!);
  5138 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5139 extra sort hypotheses that can be witnessed from the type signature;
  5140 the force_strip_shyps flag is gone, any remaining shyps are simply
  5141 left in the theorem (with a warning issued by strip_shyps_warning);
  5142 
  5143 
  5144 
  5145 New in Isabelle98-1 (October 1998)
  5146 ----------------------------------
  5147 
  5148 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5149 
  5150 * several changes of automated proof tools;
  5151 
  5152 * HOL: major changes to the inductive and datatype packages, including
  5153 some minor incompatibilities of theory syntax;
  5154 
  5155 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5156 called `inj_on';
  5157 
  5158 * HOL: removed duplicate thms in Arith:
  5159   less_imp_add_less  should be replaced by  trans_less_add1
  5160   le_imp_add_le      should be replaced by  trans_le_add1
  5161 
  5162 * HOL: unary minus is now overloaded (new type constraints may be
  5163 required);
  5164 
  5165 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5166 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5167 now taken as an integer constant.
  5168 
  5169 * Pure: ML function 'theory_of' renamed to 'theory';
  5170 
  5171 
  5172 *** Proof tools ***
  5173 
  5174 * Simplifier:
  5175   1. Asm_full_simp_tac is now more aggressive.
  5176      1. It will sometimes reorient premises if that increases their power to
  5177         simplify.
  5178      2. It does no longer proceed strictly from left to right but may also
  5179         rotate premises to achieve further simplification.
  5180      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5181      old Asm_full_simp_tac in that it does not rotate premises.
  5182   2. The simplifier now knows a little bit about nat-arithmetic.
  5183 
  5184 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5185 allows for selected deletion of wrappers, by introduction of names for
  5186 wrapper functionals.  This implies that addbefore, addSbefore,
  5187 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5188 and that adding two tactics with the same name overwrites the first
  5189 one (emitting a warning).
  5190   type wrapper = (int -> tactic) -> (int -> tactic)
  5191   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5192   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5193   delWrapper, delSWrapper: claset *  string            -> claset
  5194   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5195 
  5196 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5197 semantics; addbefore now affects only the unsafe part of step_tac
  5198 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5199 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5200 by Force_tac;
  5201 
  5202 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5203 compWrapper; added safe wrapper (and access functions for it);
  5204 
  5205 * HOL/split_all_tac is now much faster and fails if there is nothing
  5206 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5207 and the names of the automatically generated variables have changed.
  5208 split_all_tac has moved within claset() from unsafe wrappers to safe
  5209 wrappers, which means that !!-bound variables are split much more
  5210 aggressively, and safe_tac and clarify_tac now split such variables.
  5211 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5212 Note: the same holds for record_split_tac, which does the job of
  5213 split_all_tac for record fields.
  5214 
  5215 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5216 permanently to the default simpset using Addsplits just like
  5217 Addsimps. They can be removed via Delsplits just like
  5218 Delsimps. Lower-case versions are also available.
  5219 
  5220 * HOL/Simplifier: The rule split_if is now part of the default
  5221 simpset. This means that the simplifier will eliminate all occurrences
  5222 of if-then-else in the conclusion of a goal. To prevent this, you can
  5223 either remove split_if completely from the default simpset by
  5224 `Delsplits [split_if]' or remove it in a specific call of the
  5225 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5226 other case splitting rules to/from the default simpset: every datatype
  5227 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5228 t is the name of the datatype).
  5229 
  5230 * Classical reasoner / Simplifier combination: new force_tac (and
  5231 derivatives Force_tac, force) combines rewriting and classical
  5232 reasoning (and whatever other tools) similarly to auto_tac, but is
  5233 aimed to solve the given subgoal completely.
  5234 
  5235 
  5236 *** General ***
  5237 
  5238 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5239 and `goalw': the theory is no longer needed as an explicit argument -
  5240 the current theory context is used; assumptions are no longer returned
  5241 at the ML-level unless one of them starts with ==> or !!; it is
  5242 recommended to convert to these new commands using isatool fixgoal
  5243 (backup your sources first!);
  5244 
  5245 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5246 the current theory context, and 'theory' to lookup stored theories;
  5247 
  5248 * new theory section 'locale' for declaring constants, assumptions and
  5249 definitions that have local scope;
  5250 
  5251 * new theory section 'nonterminals' for purely syntactic types;
  5252 
  5253 * new theory section 'setup' for generic ML setup functions
  5254 (e.g. package initialization);
  5255 
  5256 * the distribution now includes Isabelle icons: see
  5257 lib/logo/isabelle-{small,tiny}.xpm;
  5258 
  5259 * isatool install - install binaries with absolute references to
  5260 ISABELLE_HOME/bin;
  5261 
  5262 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5263 
  5264 * print mode 'emacs' reserved for Isamode;
  5265 
  5266 * support multiple print (ast) translations per constant name;
  5267 
  5268 * theorems involving oracles are now printed with a suffixed [!];
  5269 
  5270 
  5271 *** HOL ***
  5272 
  5273 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5274 
  5275 * HOL/inductive package reorganized and improved: now supports mutual
  5276 definitions such as
  5277 
  5278   inductive EVEN ODD
  5279     intrs
  5280       null "0 : EVEN"
  5281       oddI "n : EVEN ==> Suc n : ODD"
  5282       evenI "n : ODD ==> Suc n : EVEN"
  5283 
  5284 new theorem list "elims" contains an elimination rule for each of the
  5285 recursive sets; inductive definitions now handle disjunctive premises
  5286 correctly (also ZF);
  5287 
  5288 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5289 "mutual_induct" no longer exists - the induction rule is always
  5290 contained in "induct";
  5291 
  5292 
  5293 * HOL/datatype package re-implemented and greatly improved: now
  5294 supports mutually recursive datatypes such as
  5295 
  5296   datatype
  5297     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5298             | SUM ('a aexp) ('a aexp)
  5299             | DIFF ('a aexp) ('a aexp)
  5300             | NUM 'a
  5301   and
  5302     'a bexp = LESS ('a aexp) ('a aexp)
  5303             | AND ('a bexp) ('a bexp)
  5304             | OR ('a bexp) ('a bexp)
  5305 
  5306 as well as indirectly recursive datatypes such as
  5307 
  5308   datatype
  5309     ('a, 'b) term = Var 'a
  5310                   | App 'b ((('a, 'b) term) list)
  5311 
  5312 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5313 induction on mutually / indirectly recursive datatypes.
  5314 
  5315 Primrec equations are now stored in theory and can be accessed via
  5316 <function_name>.simps.
  5317 
  5318 INCOMPATIBILITIES:
  5319 
  5320   - Theories using datatypes must now have theory Datatype as an
  5321     ancestor.
  5322   - The specific <typename>.induct_tac no longer exists - use the
  5323     generic induct_tac instead.
  5324   - natE has been renamed to nat.exhaust - use exhaust_tac
  5325     instead of res_inst_tac ... natE. Note that the variable
  5326     names in nat.exhaust differ from the names in natE, this
  5327     may cause some "fragile" proofs to fail.
  5328   - The theorems split_<typename>_case and split_<typename>_case_asm
  5329     have been renamed to <typename>.split and <typename>.split_asm.
  5330   - Since default sorts of type variables are now handled correctly,
  5331     some datatype definitions may have to be annotated with explicit
  5332     sort constraints.
  5333   - Primrec definitions no longer require function name and type
  5334     of recursive argument.
  5335 
  5336 Consider using isatool fixdatatype to adapt your theories and proof
  5337 scripts to the new package (backup your sources first!).
  5338 
  5339 
  5340 * HOL/record package: considerably improved implementation; now
  5341 includes concrete syntax for record types, terms, updates; theorems
  5342 for surjective pairing and splitting !!-bound record variables; proof
  5343 support is as follows:
  5344 
  5345   1) standard conversions (selectors or updates applied to record
  5346 constructor terms) are part of the standard simpset;
  5347 
  5348   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5349 made part of standard simpset and claset via addIffs;
  5350 
  5351   3) a tactic for record field splitting (record_split_tac) is part of
  5352 the standard claset (addSWrapper);
  5353 
  5354 To get a better idea about these rules you may retrieve them via
  5355 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5356 the name of your record type.
  5357 
  5358 The split tactic 3) conceptually simplifies by the following rule:
  5359 
  5360   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5361 
  5362 Thus any record variable that is bound by meta-all will automatically
  5363 blow up into some record constructor term, consequently the
  5364 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5365 solve record problems automatically.
  5366 
  5367 
  5368 * reorganized the main HOL image: HOL/Integ and String loaded by
  5369 default; theory Main includes everything;
  5370 
  5371 * automatic simplification of integer sums and comparisons, using cancellation;
  5372 
  5373 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5374 
  5375 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5376 
  5377 * many new identities for unions, intersections, set difference, etc.;
  5378 
  5379 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5380 called split_if, split_split, split_sum_case and split_nat_case (to go
  5381 with add/delsplits);
  5382 
  5383 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5384 (?x::unit) = (); this is made part of the default simpset, which COULD
  5385 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5386 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5387 unit_abs_eta_conv is added in order to counter the effect of
  5388 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5389 %u.f();
  5390 
  5391 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5392 makes more sense);
  5393 
  5394 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5395   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5396   disjointness reasoning but breaking a few old proofs.
  5397 
  5398 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5399 to 'converse' from 'inverse' (for compatibility with ZF and some
  5400 literature);
  5401 
  5402 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5403 the well-founded relation;
  5404 
  5405 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5406     Compl A.  The "Compl" syntax remains available as input syntax for this
  5407     release ONLY.
  5408 
  5409 * HOL/Update: new theory of function updates:
  5410     f(a:=b) == %x. if x=a then b else f x
  5411 may also be iterated as in f(a:=b,c:=d,...);
  5412 
  5413 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5414 
  5415 * HOL/List:
  5416   - new function list_update written xs[i:=v] that updates the i-th
  5417     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5418   - new function `upt' written [i..j(] which generates the list
  5419     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5420     bound write [i..j], which is a shorthand for [i..j+1(].
  5421   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5422 
  5423 * HOL/Arith:
  5424   - removed 'pred' (predecessor) function;
  5425   - generalized some theorems about n-1;
  5426   - many new laws about "div" and "mod";
  5427   - new laws about greatest common divisors (see theory ex/Primes);
  5428 
  5429 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5430 instead of "inverse";
  5431 
  5432 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5433   of the multiset ordering;
  5434 
  5435 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5436   (not included by default);
  5437 
  5438 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5439 
  5440 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5441   programs, i.e. different program variables may have different types.
  5442 
  5443 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5444   [previously, this check worked only if the rewrite rule was unconditional]
  5445   Now rew can involve either definitions or equalities (either == or =).
  5446 
  5447 
  5448 *** ZF ***
  5449 
  5450 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5451   only the theorems proved on ZF.ML;
  5452 
  5453 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5454   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5455   disjointness reasoning but breaking a few old proofs.
  5456 
  5457 * ZF/Update: new theory of function updates
  5458     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5459   may also be iterated as in f(a:=b,c:=d,...);
  5460 
  5461 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5462 
  5463 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5464   [previously, this check worked only if the rewrite rule was unconditional]
  5465   Now rew can involve either definitions or equalities (either == or =).
  5466 
  5467 * case_tac provided for compatibility with HOL
  5468     (like the old excluded_middle_tac, but with subgoals swapped)
  5469 
  5470 
  5471 *** Internal programming interfaces ***
  5472 
  5473 * Pure: several new basic modules made available for general use, see
  5474 also src/Pure/README;
  5475 
  5476 * improved the theory data mechanism to support encapsulation (data
  5477 kind name replaced by private Object.kind, acting as authorization
  5478 key); new type-safe user interface via functor TheoryDataFun; generic
  5479 print_data function becomes basically useless;
  5480 
  5481 * removed global_names compatibility flag -- all theory declarations
  5482 are qualified by default;
  5483 
  5484 * module Pure/Syntax now offers quote / antiquote translation
  5485 functions (useful for Hoare logic etc. with implicit dependencies);
  5486 see HOL/ex/Antiquote for an example use;
  5487 
  5488 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5489 cterm -> thm;
  5490 
  5491 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5492 subgoal;
  5493 
  5494 * Display.print_goals function moved to Locale.print_goals;
  5495 
  5496 * standard print function for goals supports current_goals_markers
  5497 variable for marking begin of proof, end of proof, start of goal; the
  5498 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5499 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5500 for example;
  5501 
  5502 
  5503 
  5504 New in Isabelle98 (January 1998)
  5505 --------------------------------
  5506 
  5507 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5508 
  5509 * changed lexical syntax of terms / types: dots made part of long
  5510 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5511 
  5512 * simpset (and claset) reference variable replaced by functions
  5513 simpset / simpset_ref;
  5514 
  5515 * no longer supports theory aliases (via merge) and non-trivial
  5516 implicit merge of thms' signatures;
  5517 
  5518 * most internal names of constants changed due to qualified names;
  5519 
  5520 * changed Pure/Sequence interface (see Pure/seq.ML);
  5521 
  5522 
  5523 *** General Changes ***
  5524 
  5525 * hierachically structured name spaces (for consts, types, axms, thms
  5526 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5527 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5528 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5529 long_names for fully qualified output names; NOTE: ML programs
  5530 (special tactics, packages etc.) referring to internal names may have
  5531 to be adapted to cope with fully qualified names; in case of severe
  5532 backward campatibility problems try setting 'global_names' at compile
  5533 time to have enrything declared within a flat name space; one may also
  5534 fine tune name declarations in theories via the 'global' and 'local'
  5535 section;
  5536 
  5537 * reimplemented the implicit simpset and claset using the new anytype
  5538 data filed in signatures; references simpset:simpset ref etc. are
  5539 replaced by functions simpset:unit->simpset and
  5540 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5541 to patch your ML files accordingly;
  5542 
  5543 * HTML output now includes theory graph data for display with Java
  5544 applet or isatool browser; data generated automatically via isatool
  5545 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5546 
  5547 * defs may now be conditional; improved rewrite_goals_tac to handle
  5548 conditional equations;
  5549 
  5550 * defs now admits additional type arguments, using TYPE('a) syntax;
  5551 
  5552 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5553 creates a new theory node; implicit merge of thms' signatures is
  5554 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5555 transfer:theory->thm->thm in (rare) cases;
  5556 
  5557 * improved handling of draft signatures / theories; draft thms (and
  5558 ctyps, cterms) are automatically promoted to real ones;
  5559 
  5560 * slightly changed interfaces for oracles: admit many per theory, named
  5561 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5562 
  5563 * print_goals: optional output of const types (set show_consts and
  5564 show_types);
  5565 
  5566 * improved output of warnings (###) and errors (***);
  5567 
  5568 * subgoal_tac displays a warning if the new subgoal has type variables;
  5569 
  5570 * removed old README and Makefiles;
  5571 
  5572 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5573 
  5574 * removed obsolete init_pps and init_database;
  5575 
  5576 * deleted the obsolete tactical STATE, which was declared by
  5577     fun STATE tacfun st = tacfun st st;
  5578 
  5579 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5580 (which abbreviates $HOME);
  5581 
  5582 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5583 use isatool fixseq to adapt your ML programs (this works for fully
  5584 qualified references to the Sequence structure only!);
  5585 
  5586 * use_thy no longer requires writable current directory; it always
  5587 reloads .ML *and* .thy file, if either one is out of date;
  5588 
  5589 
  5590 *** Classical Reasoner ***
  5591 
  5592 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5593 tactics that use classical reasoning to simplify a subgoal without
  5594 splitting it into several subgoals;
  5595 
  5596 * Safe_tac: like safe_tac but uses the default claset;
  5597 
  5598 
  5599 *** Simplifier ***
  5600 
  5601 * added simplification meta rules:
  5602     (asm_)(full_)simplify: simpset -> thm -> thm;
  5603 
  5604 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5605 logics (again);
  5606 
  5607 * added prems argument to simplification procedures;
  5608 
  5609 * HOL, FOL, ZF: added infix function `addsplits':
  5610   instead of `<simpset> setloop (split_tac <thms>)'
  5611   you can simply write `<simpset> addsplits <thms>'
  5612 
  5613 
  5614 *** Syntax ***
  5615 
  5616 * TYPE('a) syntax for type reflection terms;
  5617 
  5618 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5619 
  5620 * pretty printer: changed order of mixfix annotation preference (again!);
  5621 
  5622 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5623 
  5624 
  5625 *** HOL ***
  5626 
  5627 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5628   with `addloop' of the simplifier to faciliate case splitting in premises.
  5629 
  5630 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5631 
  5632 * HOL/Auth: new protocol proofs including some for the Internet
  5633   protocol TLS;
  5634 
  5635 * HOL/Map: new theory of `maps' a la VDM;
  5636 
  5637 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5638 cancelling out common nat summands from =, <, <= (in)equalities, or
  5639 differences; simplification procedures nat_cancel_factor for
  5640 cancelling common factor from =, <, <= (in)equalities over natural
  5641 sums; nat_cancel contains both kinds of procedures, it is installed by
  5642 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5643 
  5644 * HOL/simplifier: terms of the form
  5645   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5646   are rewritten to
  5647   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5648   and those of the form
  5649   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5650   are rewritten to
  5651   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5652 
  5653 * HOL/datatype
  5654   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5655 
  5656   P(t_case f1 ... fn x) =
  5657      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5658         ...
  5659        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5660      )
  5661 
  5662   and a theorem `split_t_case_asm' of the form
  5663 
  5664   P(t_case f1 ... fn x) =
  5665     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5666         ...
  5667        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5668      )
  5669   which can be added to a simpset via `addsplits'. The existing theorems
  5670   expand_list_case and expand_option_case have been renamed to
  5671   split_list_case and split_option_case.
  5672 
  5673 * HOL/Arithmetic:
  5674   - `pred n' is automatically converted to `n-1'.
  5675     Users are strongly encouraged not to use `pred' any longer,
  5676     because it will disappear altogether at some point.
  5677   - Users are strongly encouraged to write "0 < n" rather than
  5678     "n ~= 0". Theorems and proof tools have been modified towards this
  5679     `standard'.
  5680 
  5681 * HOL/Lists:
  5682   the function "set_of_list" has been renamed "set" (and its theorems too);
  5683   the function "nth" now takes its arguments in the reverse order and
  5684   has acquired the infix notation "!" as in "xs!n".
  5685 
  5686 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5687 
  5688 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5689   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5690 
  5691 * HOL/record: extensible records with schematic structural subtyping
  5692 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5693 still lacks various theorems and concrete record syntax;
  5694 
  5695 
  5696 *** HOLCF ***
  5697 
  5698 * removed "axioms" and "generated by" sections;
  5699 
  5700 * replaced "ops" section by extended "consts" section, which is capable of
  5701   handling the continuous function space "->" directly;
  5702 
  5703 * domain package:
  5704   . proves theorems immediately and stores them in the theory,
  5705   . creates hierachical name space,
  5706   . now uses normal mixfix annotations (instead of cinfix...),
  5707   . minor changes to some names and values (for consistency),
  5708   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5709   . separator between mutual domain defs: changed "," to "and",
  5710   . improved handling of sort constraints;  now they have to
  5711     appear on the left-hand side of the equations only;
  5712 
  5713 * fixed LAM <x,y,zs>.b syntax;
  5714 
  5715 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5716 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5717 
  5718 
  5719 *** FOL and ZF ***
  5720 
  5721 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5722   with `addloop' of the simplifier to faciliate case splitting in premises.
  5723 
  5724 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5725 in HOL, they strip ALL and --> from proved theorems;
  5726 
  5727 
  5728 
  5729 New in Isabelle94-8 (May 1997)
  5730 ------------------------------
  5731 
  5732 *** General Changes ***
  5733 
  5734 * new utilities to build / run / maintain Isabelle etc. (in parts
  5735 still somewhat experimental); old Makefiles etc. still functional;
  5736 
  5737 * new 'Isabelle System Manual';
  5738 
  5739 * INSTALL text, together with ./configure and ./build scripts;
  5740 
  5741 * reimplemented type inference for greater efficiency, better error
  5742 messages and clean internal interface;
  5743 
  5744 * prlim command for dealing with lots of subgoals (an easier way of
  5745 setting goals_limit);
  5746 
  5747 
  5748 *** Syntax ***
  5749 
  5750 * supports alternative (named) syntax tables (parser and pretty
  5751 printer); internal interface is provided by add_modesyntax(_i);
  5752 
  5753 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5754 be used in conjunction with the Isabelle symbol font; uses the
  5755 "symbols" syntax table;
  5756 
  5757 * added token_translation interface (may translate name tokens in
  5758 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5759 the current print_mode); IMPORTANT: user print translation functions
  5760 are responsible for marking newly introduced bounds
  5761 (Syntax.mark_boundT);
  5762 
  5763 * token translations for modes "xterm" and "xterm_color" that display
  5764 names in bold, underline etc. or colors (which requires a color
  5765 version of xterm);
  5766 
  5767 * infixes may now be declared with names independent of their syntax;
  5768 
  5769 * added typed_print_translation (like print_translation, but may
  5770 access type of constant);
  5771 
  5772 
  5773 *** Classical Reasoner ***
  5774 
  5775 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5776 some limitations.  Blast_tac...
  5777   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5778   + ignores elimination rules that don't have the correct format
  5779         (the conclusion MUST be a formula variable)
  5780   + ignores types, which can make HOL proofs fail
  5781   + rules must not require higher-order unification, e.g. apply_type in ZF
  5782     [message "Function Var's argument not a bound variable" relates to this]
  5783   + its proof strategy is more general but can actually be slower
  5784 
  5785 * substitution with equality assumptions no longer permutes other
  5786 assumptions;
  5787 
  5788 * minor changes in semantics of addafter (now called addaltern); renamed
  5789 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5790 (and access functions for it);
  5791 
  5792 * improved combination of classical reasoner and simplifier:
  5793   + functions for handling clasimpsets
  5794   + improvement of addss: now the simplifier is called _after_ the
  5795     safe steps.
  5796   + safe variant of addss called addSss: uses safe simplifications
  5797     _during_ the safe steps. It is more complete as it allows multiple
  5798     instantiations of unknowns (e.g. with slow_tac).
  5799 
  5800 *** Simplifier ***
  5801 
  5802 * added interface for simplification procedures (functions that
  5803 produce *proven* rewrite rules on the fly, depending on current
  5804 redex);
  5805 
  5806 * ordering on terms as parameter (used for ordered rewriting);
  5807 
  5808 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5809 
  5810 * the solver is now split into a safe and an unsafe part.
  5811 This should be invisible for the normal user, except that the
  5812 functions setsolver and addsolver have been renamed to setSolver and
  5813 addSolver; added safe_asm_full_simp_tac;
  5814 
  5815 
  5816 *** HOL ***
  5817 
  5818 * a generic induction tactic `induct_tac' which works for all datatypes and
  5819 also for type `nat';
  5820 
  5821 * a generic case distinction tactic `exhaust_tac' which works for all
  5822 datatypes and also for type `nat';
  5823 
  5824 * each datatype comes with a function `size';
  5825 
  5826 * patterns in case expressions allow tuple patterns as arguments to
  5827 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5828 
  5829 * primrec now also works with type nat;
  5830 
  5831 * recdef: a new declaration form, allows general recursive functions to be
  5832 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5833 
  5834 * the constant for negation has been renamed from "not" to "Not" to
  5835 harmonize with FOL, ZF, LK, etc.;
  5836 
  5837 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5838 infinite lists;
  5839 
  5840 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5841 
  5842 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  5843 problems in commutative rings, using axiomatic type classes for + and *;
  5844 
  5845 * more examples in HOL/MiniML and HOL/Auth;
  5846 
  5847 * more default rewrite rules for quantifiers, union/intersection;
  5848 
  5849 * a new constant `arbitrary == @x.False';
  5850 
  5851 * HOLCF/IOA replaces old HOL/IOA;
  5852 
  5853 * HOLCF changes: derived all rules and arities
  5854   + axiomatic type classes instead of classes
  5855   + typedef instead of faking type definitions
  5856   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5857   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5858   + eliminated the types void, one, tr
  5859   + use unit lift and bool lift (with translations) instead of one and tr
  5860   + eliminated blift from Lift3.thy (use Def instead of blift)
  5861   all eliminated rules are derived as theorems --> no visible changes ;
  5862 
  5863 
  5864 *** ZF ***
  5865 
  5866 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5867 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5868 as ZF_cs addSIs [equalityI];
  5869 
  5870 
  5871 
  5872 New in Isabelle94-7 (November 96)
  5873 ---------------------------------
  5874 
  5875 * allowing negative levels (as offsets) in prlev and choplev;
  5876 
  5877 * super-linear speedup for large simplifications;
  5878 
  5879 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  5880 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  5881 FAIL); can suppress it using the command Delsimps (ex_simps @
  5882 all_simps); De Morgan laws are also now included, by default;
  5883 
  5884 * improved printing of ==>  :  ~:
  5885 
  5886 * new object-logic "Sequents" adds linear logic, while replacing LK
  5887 and Modal (thanks to Sara Kalvala);
  5888 
  5889 * HOL/Auth: correctness proofs for authentication protocols;
  5890 
  5891 * HOL: new auto_tac combines rewriting and classical reasoning (many
  5892 examples on HOL/Auth);
  5893 
  5894 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  5895 the rewriter and classical reasoner simultaneously;
  5896 
  5897 * function uresult no longer returns theorems in "standard" format;
  5898 regain previous version by: val uresult = standard o uresult;
  5899 
  5900 
  5901 
  5902 New in Isabelle94-6
  5903 -------------------
  5904 
  5905 * oracles -- these establish an interface between Isabelle and trusted
  5906 external reasoners, which may deliver results as theorems;
  5907 
  5908 * proof objects (in particular record all uses of oracles);
  5909 
  5910 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  5911 
  5912 * "constdefs" section in theory files;
  5913 
  5914 * "primrec" section (HOL) no longer requires names;
  5915 
  5916 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  5917 
  5918 
  5919 
  5920 New in Isabelle94-5
  5921 -------------------
  5922 
  5923 * reduced space requirements;
  5924 
  5925 * automatic HTML generation from theories;
  5926 
  5927 * theory files no longer require "..." (quotes) around most types;
  5928 
  5929 * new examples, including two proofs of the Church-Rosser theorem;
  5930 
  5931 * non-curried (1994) version of HOL is no longer distributed;
  5932 
  5933 
  5934 
  5935 New in Isabelle94-4
  5936 -------------------
  5937 
  5938 * greatly reduced space requirements;
  5939 
  5940 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5941 
  5942 * searchable theorem database (see the section "Retrieving theorems" on
  5943 page 8 of the Reference Manual);
  5944 
  5945 * new examples, including Grabczewski's monumental case study of the
  5946 Axiom of Choice;
  5947 
  5948 * The previous version of HOL renamed to Old_HOL;
  5949 
  5950 * The new version of HOL (previously called CHOL) uses a curried syntax
  5951 for functions.  Application looks like f a b instead of f(a,b);
  5952 
  5953 * Mutually recursive inductive definitions finally work in HOL;
  5954 
  5955 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5956 translates to the operator "split";
  5957 
  5958 
  5959 
  5960 New in Isabelle94-3
  5961 -------------------
  5962 
  5963 * new infix operator, addss, allowing the classical reasoner to
  5964 perform simplification at each step of its search.  Example:
  5965         fast_tac (cs addss ss)
  5966 
  5967 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5968 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5969 look like (a,b) instead of <a,b>;
  5970 
  5971 * PLEASE NOTE: CHOL will eventually replace HOL!
  5972 
  5973 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5974 It translates to the operator "split".  A new theory of integers is available;
  5975 
  5976 * In ZF, integer numerals now denote two's-complement binary integers.
  5977 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5978 
  5979 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5980 of the Axiom of Choice;
  5981 
  5982 
  5983 
  5984 New in Isabelle94-2
  5985 -------------------
  5986 
  5987 * Significantly faster resolution;
  5988 
  5989 * the different sections in a .thy file can now be mixed and repeated
  5990 freely;
  5991 
  5992 * Database of theorems for FOL, HOL and ZF.  New
  5993 commands including qed, qed_goal and bind_thm store theorems in the database.
  5994 
  5995 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5996 a given theory (thms_of), or find out what theory a theorem was proved in
  5997 (theory_of_thm);
  5998 
  5999 * Bugs fixed in the inductive definition and datatype packages;
  6000 
  6001 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  6002 and HOL_dup_cs obsolete;
  6003 
  6004 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  6005 have been removed;
  6006 
  6007 * Simpler definition of function space in ZF;
  6008 
  6009 * new results about cardinal and ordinal arithmetic in ZF;
  6010 
  6011 * 'subtype' facility in HOL for introducing new types as subsets of existing
  6012 types;
  6013 
  6014 :mode=text:wrap=hard:maxLineLen=72: