NEWS
author nipkow
Tue Mar 03 17:05:18 2009 +0100 (2009-03-03)
changeset 30224 79136ce06bdb
parent 30200 0db3a35eab01
child 30235 58d147683393
permissions -rw-r--r--
removed and renamed redundant lemmas
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * The main reference manuals (isar-ref, implementation, system) have
    10 been updated and extended.  Formally checked references as hyperlinks
    11 are now available in uniform manner.
    12 
    13 * Simplified main Isabelle executables, with less surprises on
    14 case-insensitive file-systems (such as Mac OS).
    15 
    16   - The main Isabelle tool wrapper is now called "isabelle" instead of
    17     "isatool."
    18 
    19   - The former "isabelle" alias for "isabelle-process" has been
    20     removed (should rarely occur to regular users).
    21 
    22   - The former "isabelle-interface" and its alias "Isabelle" have been
    23     removed (interfaces are now regular Isabelle tools).
    24 
    25 Within scripts and make files, the Isabelle environment variables
    26 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
    27 respectively.  (The latter are still available as legacy feature.)
    28 
    29 The old isabelle-interface wrapper could react in confusing ways if
    30 the interface was uninstalled or changed otherwise.  Individual
    31 interface tool configuration is now more explicit, see also the
    32 Isabelle system manual.  In particular, Proof General is now available
    33 via "isabelle emacs".
    34 
    35 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
    36 purge installed copies of Isabelle executables and re-run "isabelle
    37 install -p ...", or use symlinks.
    38 
    39 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
    40 old ~/isabelle, which was slightly non-standard and apt cause
    41 surprises on case-insensitive file-systems.
    42 
    43 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
    44 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
    45 care is required when using older releases of Isabelle.  Note that
    46 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
    47 Isabelle distribution.
    48 
    49 * Proofs of fully specified statements are run in parallel on
    50 multi-core systems.  A speedup factor of 2-3 can be expected on a
    51 regular 4-core machine, if the initial heap space is made reasonably
    52 large (cf. Poly/ML option -H).  [Poly/ML 5.2.1 or later]
    53 
    54 * Generalized Isar history, with support for linear undo, direct state
    55 addressing etc.
    56 
    57 * Recovered hiding of consts, which was accidentally broken in
    58 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
    59 makes c inaccessible; consider using ``hide (open) const c'' instead.
    60 
    61 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
    62 interface instead.
    63 
    64 * There is a new syntactic category "float_const" for signed decimal
    65 fractions (e.g. 123.45 or -123.45).
    66 
    67 * New prover for coherent logic (see src/Tools/coherent.ML).
    68 
    69 
    70 *** Pure ***
    71 
    72 * Class declaration: sc. "base sort" must not be given in import list
    73 any longer but is inferred from the specification.  Particularly in HOL,
    74 write
    75 
    76     class foo = ...     instead of      class foo = type + ...
    77 
    78 * Type binding gradually replaces formerly used type bstring for names
    79 to be bound.  Name space interface for declarations has been simplified:
    80 
    81   NameSpace.declare: NameSpace.naming
    82     -> binding -> NameSpace.T -> string * NameSpace.T
    83   NameSpace.bind: NameSpace.naming
    84     -> binding * 'a -> 'a NameSpace.table -> string * 'a NameSpace.table
    85          (*exception Symtab.DUP*)
    86 
    87 See further modules src/Pure/General/binding.ML and
    88 src/Pure/General/name_space.ML
    89 
    90 * Module moves in repository:
    91     src/Pure/Tools/value.ML ~> src/Tools/
    92     src/Pure/Tools/quickcheck.ML ~> src/Tools/
    93 
    94 * Slightly more coherent Pure syntax, with updated documentation in
    95 isar-ref manual.  Removed locales meta_term_syntax and
    96 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
    97 INCOMPATIBILITY in rare situations.
    98 
    99 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
   100 hypotheses.  Sorts required in the course of reasoning need to be
   101 covered by the constraints in the initial statement, completed by the
   102 type instance information of the background theory.  Non-trivial sort
   103 hypotheses, which rarely occur in practice, may be specified via
   104 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
   105 
   106   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
   107 
   108 The result contains an implicit sort hypotheses as before --
   109 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   110 normalization.
   111 
   112 * Changed defaults for unify configuration options:
   113 
   114   unify_trace_bound = 50 (formerly 25)
   115   unify_search_bound = 60 (formerly 30)
   116 
   117 * Different bookkeeping for code equations (INCOMPATIBILITY):
   118 
   119   a) On theory merge, the last set of code equations for a particular
   120      constant is taken (in accordance with the policy applied by other
   121      parts of the code generator framework).
   122 
   123   b) Code equations stemming from explicit declarations (e.g. code
   124      attribute) gain priority over default code equations stemming
   125      from definition, primrec, fun etc.
   126 
   127 * Global versions of theorems stemming from classes do not carry a
   128 parameter prefix any longer.  INCOMPATIBILITY.
   129 
   130 * Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   131 In existing theorem specifications replace the includes element by the
   132 respective context elements of the included locale, omitting those
   133 that are already present in the theorem specification.  Multiple
   134 assume elements of a locale should be replaced by a single one
   135 involving the locale predicate.  In the proof body, declarations (most
   136 notably theorems) may be regained by interpreting the respective
   137 locales in the proof context as required (command "interpret").
   138 
   139 If using "includes" in replacement of a target solely because the
   140 parameter types in the theorem are not as general as in the target,
   141 consider declaring a new locale with additional type constraints on
   142 the parameters (context element "constrains").
   143 
   144 * Dropped "locale (open)".  INCOMPATIBILITY.
   145 
   146 * Interpretation commands no longer attempt to simplify goal.
   147 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   148 methods intro_locales and unfold_locales to clarify.
   149 
   150 * Interpretation commands no longer accept interpretation attributes.
   151 INCOMPATBILITY.
   152 
   153 * Complete re-implementation of locales.  INCOMPATIBILITY.  The most
   154 important changes are listed below.  See documentation (forthcoming)
   155 and tutorial (also forthcoming) for details.
   156 
   157 - In locale expressions, instantiation replaces renaming.  Parameters
   158 must be declared in a for clause.  To aid compatibility with previous
   159 parameter inheritance, in locale declarations, parameters that are not
   160 'touched' (instantiation position "_" or omitted) are implicitly added
   161 with their syntax at the beginning of the for clause.
   162 
   163 - Syntax from abbreviations and definitions in locales is available in
   164 locale expressions and context elements.  The latter is particularly
   165 useful in locale declarations.
   166 
   167 - More flexible mechanisms to qualify names generated by locale
   168 expressions.  Qualifiers (prefixes) may be specified in locale
   169 expressions.  Available are normal qualifiers (syntax "name:") and
   170 strict qualifiers (syntax "name!:").  The latter must occur in name
   171 references and are useful to avoid accidental hiding of names, the
   172 former are optional.  Qualifiers derived from the parameter names of a
   173 locale are no longer generated.
   174 
   175 - "sublocale l < e" replaces "interpretation l < e".  The
   176 instantiation clause in "interpretation" and "interpret" (square
   177 brackets) is no longer available.  Use locale expressions.
   178 
   179 - When converting proof scripts, be sure to replace qualifiers in
   180 "interpretation" and "interpret" by strict qualifiers.  Qualifiers in
   181 locale expressions range over a single locale instance only.
   182 
   183 * Command 'instance': attached definitions no longer accepted.
   184 INCOMPATIBILITY, use proper 'instantiation' target.
   185 
   186 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   187 
   188 * The 'axiomatization' command now only works within a global theory
   189 context.  INCOMPATIBILITY.
   190 
   191 * New find_theorems criterion "solves" matching theorems that directly
   192 solve the current goal. Try "find_theorems solves".
   193 
   194 * Added an auto solve option, which can be enabled through the
   195 ProofGeneral Isabelle settings menu (disabled by default).
   196  
   197 When enabled, find_theorems solves is called whenever a new lemma is
   198 stated. Any theorems that could solve the lemma directly are listed
   199 underneath the goal.
   200 
   201 * New command find_consts searches for constants based on type and
   202 name patterns, e.g.
   203 
   204     find_consts "_ => bool"
   205 
   206 By default, matching is against subtypes, but it may be restricted to
   207 the whole type. Searching by name is possible. Multiple queries are
   208 conjunctive and queries may be negated by prefixing them with a
   209 hyphen:
   210 
   211     find_consts strict: "_ => bool" name: "Int" -"int => int"
   212 
   213 
   214 *** Document preparation ***
   215 
   216 * Antiquotation @{lemma} now imitates a regular terminal proof,
   217 demanding keyword 'by' and supporting the full method expression
   218 syntax just like the Isar command 'by'.
   219 
   220 
   221 *** HOL ***
   222 
   223 * Auxiliary class "itself" has disappeared -- classes without any parameter
   224 are treated as expected by the 'class' command.
   225 
   226 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   227 
   228 * Common decision procedures (Cooper, MIR, Ferrack, Approximation, Dense_Linear_Order)
   229 now in directory HOL/Decision_Procs.
   230 
   231 * Theory HOL/Decisioin_Procs/Approximation.thy provides the new proof method
   232 "approximation".  It proves formulas on real values by using interval arithmetic.
   233 In the formulas are also the transcendental functions sin, cos, tan, atan, ln,
   234 exp and the constant pi are allowed.  For examples see HOL/ex/ApproximationEx.thy.
   235 
   236 * Theory "Reflection" now resides in HOL/Library.
   237 
   238 * Entry point to Word library now simply named "Word".  INCOMPATIBILITY.
   239 
   240 * Made source layout more coherent with logical distribution
   241 structure:
   242 
   243     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   244     src/HOL/Library/Code_Message.thy ~> src/HOL/
   245     src/HOL/Library/GCD.thy ~> src/HOL/
   246     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   247     src/HOL/Library/Parity.thy ~> src/HOL/
   248     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   249     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   250     src/HOL/Real/Lubs.thy ~> src/HOL/
   251     src/HOL/Real/PReal.thy ~> src/HOL/
   252     src/HOL/Real/Rational.thy ~> src/HOL/
   253     src/HOL/Real/RComplete.thy ~> src/HOL/
   254     src/HOL/Real/RealDef.thy ~> src/HOL/
   255     src/HOL/Real/RealPow.thy ~> src/HOL/
   256     src/HOL/Real/Real.thy ~> src/HOL/
   257     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   258     src/HOL/Complex/Complex.thy ~> src/HOL/
   259     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   260     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   261     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   262     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   263     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   264     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   265     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   266     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   267     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   268     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   269     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   270     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   271     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   272     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   273     src/HOL/Real/Float ~> src/HOL/Library/
   274     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   275     src/HOL/Real/RealVector.thy ~> src/HOL/
   276 
   277     src/HOL/arith_data.ML ~> src/HOL/Tools
   278     src/HOL/hologic.ML ~> src/HOL/Tools
   279     src/HOL/simpdata.ML ~> src/HOL/Tools
   280     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   281     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   282     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   283     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   284     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   285     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   286     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   287 
   288     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   289     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   290     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   291     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   292     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   293     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   294 
   295 * If methods "eval" and "evaluation" encounter a structured proof state
   296 with !!/==>, only the conclusion is evaluated to True (if possible),
   297 avoiding strange error messages.
   298 
   299 * Simplifier: simproc for let expressions now unfolds if bound variable
   300 occurs at most one time in let expression body.  INCOMPATIBILITY.
   301 
   302 * New classes "top" and "bot" with corresponding operations "top" and "bot"
   303 in theory Orderings;  instantiation of class "complete_lattice" requires
   304 instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   305 
   306 * Changed definition lemma "less_fun_def" in order to provide an instance
   307 for preorders on functions;  use lemma "less_le" instead.  INCOMPATIBILITY.
   308 
   309 * Unified theorem tables for both code code generators.  Thus
   310 [code func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   311 
   312 * Constants "undefined" and "default" replace "arbitrary".  Usually
   313 "undefined" is the right choice to replace "arbitrary", though logically
   314 there is no difference.  INCOMPATIBILITY.
   315 
   316 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   317 Posix processes.  Avoids potentially expensive forking of the ML
   318 process.  New thread-based implementation also works on non-Unix
   319 platforms (Cygwin).  Provers are no longer hardwired, but defined
   320 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   321 commands are covered in the isar-ref manual.
   322 
   323 * Wrapper scripts for remote SystemOnTPTP service allows to use
   324 sledgehammer without local ATP installation (Vampire etc.).  See also
   325 ISABELLE_HOME/contrib/SystemOnTPTP and the VAMPIRE_HOME setting
   326 variable.  Other provers may be included via suitable ML wrappers, see
   327 also src/HOL/ATP_Linkup.thy.
   328 
   329 * Normalization by evaluation now allows non-leftlinear equations.
   330 Declare with attribute [code nbe].
   331 
   332 * Command "value" now integrates different evaluation
   333 mechanisms.  The result of the first successful evaluation mechanism
   334 is printed.  In square brackets a particular named evaluation
   335 mechanisms may be specified (currently, [SML], [code] or [nbe]).  See
   336 further src/HOL/ex/Eval_Examples.thy.
   337 
   338 * New method "sizechange" to automate termination proofs using (a
   339 modification of) the size-change principle. Requires SAT solver. See
   340 src/HOL/ex/Termination.thy for examples.
   341 
   342 * HOL/Orderings: class "wellorder" moved here, with explicit induction
   343 rule "less_induct" as assumption.  For instantiation of "wellorder" by
   344 means of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.
   345 
   346 * HOL/Orderings: added class "preorder" as superclass of "order".
   347 INCOMPATIBILITY: Instantiation proofs for order, linorder
   348 etc. slightly changed.  Some theorems named order_class.* now named
   349 preorder_class.*.
   350 
   351 * HOL/Relation:
   352 Renamed "refl" to "refl_on", "reflexive" to "refl, "diag" to "Id_on".
   353 
   354 * HOL/Finite_Set: added a new fold combinator of type
   355   ('a => 'b => 'b) => 'b => 'a set => 'b
   356 Occasionally this is more convenient than the old fold combinator which is
   357 now defined in terms of the new one and renamed to fold_image.
   358 
   359 * HOL/Ring_and_Field and HOL/OrderedGroup: The lemmas "group_simps" and
   360 "ring_simps" have been replaced by "algebra_simps" (which can be extended with
   361 further lemmas!). At the moment both still exist but the former will disappear
   362 at some point.
   363 
   364 * HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
   365 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   366 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   367 of lemmas from Divides has been generalized from nat to class
   368 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   369 renames resulting from duplicate elimination:
   370 
   371     dvd_def_mod ~>          dvd_eq_mod_eq_0
   372     zero_dvd_iff ~>         dvd_0_left_iff
   373     dvd_0 ~>                dvd_0_right
   374     DIVISION_BY_ZERO_DIV ~> div_by_0
   375     DIVISION_BY_ZERO_MOD ~> mod_by_0
   376     mult_div ~>             div_mult_self2_is_id
   377     mult_mod ~>             mod_mult_self2_is_0
   378 
   379 * HOL/IntDiv: removed many lemmas that are instances of class-based
   380 generalizations (from Divides and Ring_and_Field).
   381 INCOMPATIBILITY. Rename old lemmas as follows:
   382 
   383 dvd_diff               -> nat_dvd_diff
   384 dvd_zminus_iff         -> dvd_minus_iff
   385 mod_add1_eq            -> mod_add_eq
   386 mod_mult1_eq           -> mod_mult_right_eq
   387 mod_mult1_eq'          -> mod_mult_left_eq
   388 mod_mult_distrib_mod   -> mod_mult_eq
   389 nat_mod_add_left_eq    -> mod_add_left_eq
   390 nat_mod_add_right_eq   -> mod_add_right_eq
   391 nat_mod_div_trivial    -> mod_div_trivial
   392 nat_mod_mod_trivial    -> mod_mod_trivial
   393 zdiv_zadd_self1        -> div_add_self1
   394 zdiv_zadd_self2        -> div_add_self2
   395 zdiv_zmult_self1       -> div_mult_self2_is_id
   396 zdiv_zmult_self2       -> div_mult_self1_is_id
   397 zdvd_triv_left         -> dvd_triv_left
   398 zdvd_triv_right        -> dvd_triv_right
   399 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   400 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   401 zmod_zadd_left_eq      -> mod_add_left_eq
   402 zmod_zadd_right_eq     -> mod_add_right_eq
   403 zmod_zadd_self1        -> mod_add_self1
   404 zmod_zadd_self2        -> mod_add_self2
   405 zmod_zadd1_eq          -> mod_add_eq
   406 zmod_zdiff1_eq         -> mod_diff_eq
   407 zmod_zdvd_zmod         -> mod_mod_cancel
   408 zmod_zmod_cancel       -> mod_mod_cancel
   409 zmod_zmult_self1       -> mod_mult_self2_is_0
   410 zmod_zmult_self2       -> mod_mult_self1_is_0
   411 zmod_1                 -> mod_by_1
   412 zdiv_1                 -> div_by_1
   413 zdvd_abs1              -> abs_dvd_iff
   414 zdvd_abs2              -> dvd_abs_iff
   415 zdvd_refl              -> dvd_refl
   416 zdvd_trans             -> dvd_trans
   417 zdvd_zadd              -> dvd_add
   418 zdvd_zdiff             -> dvd_diff
   419 zdvd_zminus_iff        -> dvd_minus_iff
   420 zdvd_zminus2_iff       -> minus_dvd_iff
   421 zdvd_zmultD            -> dvd_mult_right
   422 zdvd_zmultD2           -> dvd_mult_left
   423 zdvd_zmult_mono        -> mult_dvd_mono
   424 zdvd_0_right           -> dvd_0_right
   425 zdvd_0_left            -> dvd_0_left_iff
   426 zdvd_1_left            -> one_dvd
   427 zminus_dvd_iff         -> minus_dvd_iff
   428 
   429 * HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   430 zlcm (for int); carried together from various gcd/lcm developements in
   431 the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
   432 corresponding theorems renamed accordingly.  INCOMPATIBILITY.  To
   433 recover tupled syntax, use syntax declarations like:
   434 
   435     hide (open) const gcd
   436     abbreviation gcd where
   437       "gcd == (%(a, b). GCD.gcd a b)"
   438     notation (output)
   439       GCD.gcd ("gcd '(_, _')")
   440 
   441 (analogously for lcm, zgcd, zlcm).
   442 
   443 * HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   444 
   445 * The real numbers offer decimal input syntax: 12.34 is translated into
   446   1234/10^2. This translation is not reversed upon output.
   447 
   448 * New ML antiquotation @{code}: takes constant as argument, generates
   449 corresponding code in background and inserts name of the corresponding
   450 resulting ML value/function/datatype constructor binding in place.
   451 All occurrences of @{code} with a single ML block are generated
   452 simultaneously.  Provides a generic and safe interface for
   453 instrumentalizing code generation.  See HOL/ex/Code_Antiq for a toy
   454 example, or HOL/Complex/ex/ReflectedFerrack for a more ambitious
   455 application.  In future you ought refrain from ad-hoc compiling
   456 generated SML code on the ML toplevel.  Note that (for technical
   457 reasons) @{code} cannot refer to constants for which user-defined
   458 serializations are set.  Refer to the corresponding ML counterpart
   459 directly in that cases.
   460 
   461 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   462 Complex_Main.thy remain as they are.
   463 
   464 * New image HOL-Plain provides a minimal HOL with the most important
   465 tools available (inductive, datatype, primrec, ...).  By convention
   466 the corresponding theory Plain should be ancestor of every further
   467 (library) theory.  Some library theories now have ancestor Plain
   468 (instead of Main), thus theory Main occasionally has to be imported
   469 explicitly.
   470 
   471 * The metis method now fails in the usual manner, rather than raising
   472 an exception, if it determines that it cannot prove the theorem.
   473 
   474 * The metis method no longer fails because the theorem is too trivial
   475 (contains the empty clause).
   476 
   477 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   478 as the structured Isar versions "cases" and "induct", cf. the
   479 corresponding "cases" and "induct" attributes.  Mutual induction rules
   480 are now presented as a list of individual projections
   481 (e.g. foo_bar.inducts for types foo and bar); the old format with
   482 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   483 rare situations a different rule is selected --- notably nested tuple
   484 elimination instead of former prod.exhaust: use explicit (case_tac t
   485 rule: prod.exhaust) here.
   486 
   487 * Attributes "cases", "induct", "coinduct" support "del" option.
   488 
   489 * Removed fact "case_split_thm", which duplicates "case_split".
   490 
   491 * Command 'rep_datatype': instead of theorem names the command now
   492 takes a list of terms denoting the constructors of the type to be
   493 represented as datatype.  The characteristic theorems have to be
   494 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   495 have disappeared in favour of existing ones:
   496 
   497     unit_induct                 ~> unit.induct
   498     prod_induct                 ~> prod.induct
   499     sum_induct                  ~> sum.induct
   500     Suc_Suc_eq                  ~> nat.inject
   501     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   502 
   503 * Library/Nat_Infinity: added addition, numeral syntax and more
   504 instantiations for algebraic structures.  Removed some duplicate
   505 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   506 
   507 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   508 menu.
   509 
   510 
   511 *** HOL-Algebra ***
   512 
   513 * New locales for orders and lattices where the equivalence relation
   514 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   515 locales use a record structure with field eq for the equivalence.
   516 
   517 * New theory of factorial domains.
   518 
   519 * Units_l_inv and Units_r_inv are now simprules by default.
   520 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   521 and/or r_inv will now also require deletion of these lemmas.
   522 
   523 * Renamed the following theorems.  INCOMPATIBILITY.
   524 UpperD ~> Upper_memD
   525 LowerD ~> Lower_memD
   526 least_carrier ~> least_closed
   527 greatest_carrier ~> greatest_closed
   528 greatest_Lower_above ~> greatest_Lower_below
   529 one_zero ~> carrier_one_zero
   530 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   531 
   532 
   533 *** HOL-NSA ***
   534 
   535 * Created new image HOL-NSA, containing theories of nonstandard
   536 analysis which were previously part of HOL-Complex.  Entry point
   537 Hyperreal.thy remains valid, but theories formerly using
   538 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   539 
   540 
   541 *** ZF ***
   542 
   543 * Proof of Zorn's Lemma for partial orders.
   544 
   545 
   546 *** HOLCF ***
   547 
   548 * Reimplemented the simplification procedure for proving continuity
   549 subgoals.  The new simproc is extensible; users can declare additional
   550 continuity introduction rules with the attribute [cont2cont].
   551 
   552 * The continuity simproc now uses a different introduction rule for
   553 solving continuity subgoals on terms with lambda abstractions.  In
   554 some rare cases the new simproc may fail to solve subgoals that the
   555 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   556 Potential INCOMPATIBILITY.
   557 
   558 * The syntax of the fixrec package has changed.  The specification
   559 syntax now conforms in style to definition, primrec, function, etc.
   560 See HOLCF/ex/Fixrec_ex.thy for examples.  INCOMPATIBILITY.
   561 
   562 
   563 *** ML ***
   564 
   565 * High-level support for concurrent ML programming, see
   566 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   567 particularly convenient to organize independent functional
   568 computations.  The concept of "synchronized variables" provides a
   569 higher-order interface for components with shared state, avoiding the
   570 delicate details of mutexes and condition variables.  [Poly/ML 5.2.1
   571 or later]
   572 
   573 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   574 to 'a -> thm, while results are always tagged with an authentic oracle
   575 name.  The Isar command 'oracle' is now polymorphic, no argument type
   576 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   577 accordingly.  Note that extra performance may be gained by producing
   578 the cterm carefully, avoiding slow Thm.cterm_of.
   579 
   580 * ML bindings produced via Isar commands are stored within the Isar
   581 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   582 become thread-safe and work with undo as expected (concerning
   583 top-level bindings, not side-effects on global references).
   584 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   585 compiler at runtime; really global bindings need to be given outside a
   586 theory. [Poly/ML 5.2 or later]
   587 
   588 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   589 context. Top-level ML bindings are stored within the proof context in
   590 a purely sequential fashion, disregarding the nested proof structure.
   591 ML bindings introduced by 'ML_prf' are discarded at the end of the
   592 proof.  [Poly/ML 5.2 or later]
   593 
   594 * Generic Toplevel.add_hook interface allows to analyze the result of
   595 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   596 for theorem dependency output of transactions resulting in a new
   597 theory state.
   598 
   599 * Name bindings in higher specification mechanisms (notably
   600 LocalTheory.define, LocalTheory.note, and derived packages) are now
   601 formalized as type Name.binding, replacing old bstring.
   602 INCOMPATIBILITY, need to wrap strings via Name.binding function, see
   603 also Name.name_of.  Packages should pass name bindings given by the
   604 user to underlying specification mechanisms; this enables precise
   605 tracking of source positions, for example.
   606 
   607 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   608 LocalTheory.note etc.) now refer to the *full* internal name, not the
   609 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   610 
   611 * Rules and tactics that read instantiations (read_instantiate,
   612 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   613 context, which is required for parsing and type-checking.  Moreover,
   614 the variables are specified as plain indexnames, not string encodings
   615 thereof.  INCOMPATIBILITY.
   616 
   617 * Disposed old type and term read functions (Sign.read_def_typ,
   618 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   619 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   620 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   621 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   622 resort for legacy applications.
   623 
   624 * Antiquotations: block-structured compilation context indicated by
   625 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   626 
   627   @{let ?pat = term}                      - term abbreviation (HO matching)
   628   @{note name = fact}                     - fact abbreviation
   629   @{thm fact}                             - singleton fact (with attributes)
   630   @{thms fact}                            - general fact (with attributes)
   631   @{lemma prop by method}                 - singleton goal
   632   @{lemma prop by meth1 meth2}            - singleton goal
   633   @{lemma prop1 ... propN by method}      - general goal
   634   @{lemma prop1 ... propN by meth1 meth2} - general goal
   635   @{lemma (open) ...}                     - open derivation
   636 
   637 
   638 *** System ***
   639 
   640 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   641 Poly/ML 5.2.1 or later.
   642 
   643 * The Isabelle "emacs" tool provides a specific interface to invoke
   644 Proof General / Emacs, with more explicit failure if that is not
   645 installed (the old isabelle-interface script silently falls back on
   646 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   647 installation location of the Proof General distribution.
   648 
   649 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   650 the Isabelle process into a JVM/Scala application.  See
   651 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   652 process wrapper has been discontinued.)
   653 
   654 * Status messages (with exact source position information) are
   655 emitted, if proper markup print mode is enabled.  This allows
   656 user-interface components to provide detailed feedback on internal
   657 prover operations.
   658 
   659 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   660 
   661 
   662 
   663 New in Isabelle2008 (June 2008)
   664 -------------------------------
   665 
   666 *** General ***
   667 
   668 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   669 and updated, with formally checked references as hyperlinks.
   670 
   671 * Theory loader: use_thy (and similar operations) no longer set the
   672 implicit ML context, which was occasionally hard to predict and in
   673 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   674 provides a proper context already.
   675 
   676 * Theory loader: old-style ML proof scripts being *attached* to a thy
   677 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   678 'use' within a theory file will do the job.
   679 
   680 * Name space merge now observes canonical order, i.e. the second space
   681 is inserted into the first one, while existing entries in the first
   682 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   683 swap theory imports.
   684 
   685 * Syntax: symbol \<chi> is now considered a letter.  Potential
   686 INCOMPATIBILITY in identifier syntax etc.
   687 
   688 * Outer syntax: string tokens no longer admit escaped white space,
   689 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   690 white space without escapes.
   691 
   692 * Outer syntax: string tokens may contain arbitrary character codes
   693 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   694 "foo_bar".
   695 
   696 
   697 *** Pure ***
   698 
   699 * Context-dependent token translations.  Default setup reverts locally
   700 fixed variables, and adds hilite markup for undeclared frees.
   701 
   702 * Unused theorems can be found using the new command 'unused_thms'.
   703 There are three ways of invoking it:
   704 
   705 (1) unused_thms
   706      Only finds unused theorems in the current theory.
   707 
   708 (2) unused_thms thy_1 ... thy_n -
   709      Finds unused theorems in the current theory and all of its ancestors,
   710      excluding the theories thy_1 ... thy_n and all of their ancestors.
   711 
   712 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   713      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   714      their ancestors, excluding the theories thy_1 ... thy_n and all of
   715      their ancestors.
   716 
   717 In order to increase the readability of the list produced by
   718 unused_thms, theorems that have been created by a particular instance
   719 of a theory command such as 'inductive' or 'function' are considered
   720 to belong to the same "group", meaning that if at least one theorem in
   721 this group is used, the other theorems in the same group are no longer
   722 reported as unused.  Moreover, if all theorems in the group are
   723 unused, only one theorem in the group is displayed.
   724 
   725 Note that proof objects have to be switched on in order for
   726 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   727 usually the case when using Proof General with the default settings).
   728 
   729 * Authentic naming of facts disallows ad-hoc overwriting of previous
   730 theorems within the same name space.  INCOMPATIBILITY, need to remove
   731 duplicate fact bindings, or even accidental fact duplications.  Note
   732 that tools may maintain dynamically scoped facts systematically, using
   733 PureThy.add_thms_dynamic.
   734 
   735 * Command 'hide' now allows to hide from "fact" name space as well.
   736 
   737 * Eliminated destructive theorem database, simpset, claset, and
   738 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   739 update of theories within ML code.
   740 
   741 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   742 INCOMPATIBILITY, object-logics depending on former Pure require
   743 additional setup PureThy.old_appl_syntax_setup; object-logics
   744 depending on former CPure need to refer to Pure.
   745 
   746 * Commands 'use' and 'ML' are now purely functional, operating on
   747 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   748 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   749 INCOMPATIBILITY.
   750 
   751 * Command 'setup': discontinued implicit version with ML reference.
   752 
   753 * Instantiation target allows for simultaneous specification of class
   754 instance operations together with an instantiation proof.
   755 Type-checking phase allows to refer to class operations uniformly.
   756 See src/HOL/Complex/Complex.thy for an Isar example and
   757 src/HOL/Library/Eval.thy for an ML example.
   758 
   759 * Indexing of literal facts: be more serious about including only
   760 facts from the visible specification/proof context, but not the
   761 background context (locale etc.).  Affects `prop` notation and method
   762 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   763 situations.
   764 
   765 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   766 "(open)" option, which used to expose internal bound variables to the
   767 proof text.
   768 
   769 * Isar statements: removed obsolete case "rule_context".
   770 INCOMPATIBILITY, better use explicit fixes/assumes.
   771 
   772 * Locale proofs: default proof step now includes 'unfold_locales';
   773 hence 'proof' without argument may be used to unfold locale
   774 predicates.
   775 
   776 
   777 *** Document preparation ***
   778 
   779 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   780 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   781 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   782 spot); renamed link color from "darkblue" to "linkcolor" (default
   783 value unchanged, can be redefined via \definecolor); no longer sets
   784 "a4paper" option (unnecessary or even intrusive).
   785 
   786 * Antiquotation @{lemma A method} proves proposition A by the given
   787 method (either a method name or a method name plus (optional) method
   788 arguments in parentheses) and prints A just like @{prop A}.
   789 
   790 
   791 *** HOL ***
   792 
   793 * New primrec package.  Specification syntax conforms in style to
   794 definition/function/....  No separate induction rule is provided.  The
   795 "primrec" command distinguishes old-style and new-style specifications
   796 by syntax.  The former primrec package is now named OldPrimrecPackage.
   797 When adjusting theories, beware: constants stemming from new-style
   798 primrec specifications have authentic syntax.
   799 
   800 * Metis prover is now an order of magnitude faster, and also works
   801 with multithreading.
   802 
   803 * Metis: the maximum number of clauses that can be produced from a
   804 theorem is now given by the attribute max_clauses.  Theorems that
   805 exceed this number are ignored, with a warning printed.
   806 
   807 * Sledgehammer no longer produces structured proofs by default. To
   808 enable, declare [[sledgehammer_full = true]].  Attributes
   809 reconstruction_modulus, reconstruction_sorts renamed
   810 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   811 
   812 * Method "induct_scheme" derives user-specified induction rules
   813 from well-founded induction and completeness of patterns. This factors
   814 out some operations that are done internally by the function package
   815 and makes them available separately.  See
   816 src/HOL/ex/Induction_Scheme.thy for examples.
   817 
   818 * More flexible generation of measure functions for termination
   819 proofs: Measure functions can be declared by proving a rule of the
   820 form "is_measure f" and giving it the [measure_function] attribute.
   821 The "is_measure" predicate is logically meaningless (always true), and
   822 just guides the heuristic.  To find suitable measure functions, the
   823 termination prover sets up the goal "is_measure ?f" of the appropriate
   824 type and generates all solutions by prolog-style backwards proof using
   825 the declared rules.
   826 
   827 This setup also deals with rules like 
   828 
   829   "is_measure f ==> is_measure (list_size f)"
   830 
   831 which accommodates nested datatypes that recurse through lists.
   832 Similar rules are predeclared for products and option types.
   833 
   834 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   835 
   836   INCOMPATIBILITIES:
   837 
   838   - Definitions of overloaded constants on sets have to be replaced by
   839     definitions on => and bool.
   840 
   841   - Some definitions of overloaded operators on sets can now be proved
   842     using the definitions of the operators on => and bool.  Therefore,
   843     the following theorems have been renamed:
   844 
   845       subset_def   -> subset_eq
   846       psubset_def  -> psubset_eq
   847       set_diff_def -> set_diff_eq
   848       Compl_def    -> Compl_eq
   849       Sup_set_def  -> Sup_set_eq
   850       Inf_set_def  -> Inf_set_eq
   851       sup_set_def  -> sup_set_eq
   852       inf_set_def  -> inf_set_eq
   853 
   854   - Due to the incompleteness of the HO unification algorithm, some
   855     rules such as subst may require manual instantiation, if some of
   856     the unknowns in the rule is a set.
   857 
   858   - Higher order unification and forward proofs:
   859     The proof pattern
   860 
   861       have "P (S::'a set)" <...>
   862       then have "EX S. P S" ..
   863 
   864     no longer works (due to the incompleteness of the HO unification
   865     algorithm) and must be replaced by the pattern
   866 
   867       have "EX S. P S"
   868       proof
   869         show "P S" <...>
   870       qed
   871 
   872   - Calculational reasoning with subst (or similar rules):
   873     The proof pattern
   874 
   875       have "P (S::'a set)" <...>
   876       also have "S = T" <...>
   877       finally have "P T" .
   878 
   879     no longer works (for similar reasons as the previous example) and
   880     must be replaced by something like
   881 
   882       have "P (S::'a set)" <...>
   883       moreover have "S = T" <...>
   884       ultimately have "P T" by simp
   885 
   886   - Tactics or packages written in ML code:
   887     Code performing pattern matching on types via
   888 
   889       Type ("set", [T]) => ...
   890 
   891     must be rewritten. Moreover, functions like strip_type or
   892     binder_types no longer return the right value when applied to a
   893     type of the form
   894 
   895       T1 => ... => Tn => U => bool
   896 
   897     rather than
   898 
   899       T1 => ... => Tn => U set
   900 
   901 * Merged theories Wellfounded_Recursion, Accessible_Part and
   902 Wellfounded_Relations to theory Wellfounded.
   903 
   904 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   905 
   906 * Class finite no longer treats UNIV as class parameter.  Use class
   907 enum from theory Library/Enum instead to achieve a similar effect.
   908 INCOMPATIBILITY.
   909 
   910 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   911 and "Cons".  INCOMPATIBILITY.
   912 
   913 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   914 Potential INCOMPATIBILITY.
   915 
   916 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   917 injective_fst_snd removed, use split_eta and prod_eqI instead.
   918 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   919 
   920 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   921 the same name in theory Orderings:
   922 
   923   less_trans
   924   less_linear
   925   le_imp_less_or_eq
   926   le_less_trans
   927   less_le_trans
   928   less_not_sym
   929   less_asym
   930 
   931 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
   932 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
   933 and different variable names.
   934 
   935 * Library/Option_ord.thy: Canonical order on option type.
   936 
   937 * Library/RBT.thy: Red-black trees, an efficient implementation of
   938 finite maps.
   939 
   940 * Library/Countable.thy: Type class for countable types.
   941 
   942 * Theory Int: The representation of numerals has changed.  The infix
   943 operator BIT and the bit datatype with constructors B0 and B1 have
   944 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
   945 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
   946 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
   947 accordingly.
   948 
   949 * Theory Nat: definition of <= and < on natural numbers no longer
   950 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
   951 le_def and less_def have disappeared.  Consider lemmas not_less
   952 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
   953 
   954 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
   955 (whose purpose mainly is for various fold_set functionals) have been
   956 abandoned in favor of the existing algebraic classes
   957 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
   958 lower_semilattice (resp. upper_semilattice) and linorder.
   959 INCOMPATIBILITY.
   960 
   961 * Theory Transitive_Closure: induct and cases rules now declare proper
   962 case_names ("base" and "step").  INCOMPATIBILITY.
   963 
   964 * Theorem Inductive.lfp_ordinal_induct generalized to complete
   965 lattices.  The form set-specific version is available as
   966 Inductive.lfp_ordinal_induct_set.
   967 
   968 * Renamed theorems "power.simps" to "power_int.simps".
   969 INCOMPATIBILITY.
   970 
   971 * Class semiring_div provides basic abstract properties of semirings
   972 with division and modulo operations.  Subsumes former class dvd_mod.
   973 
   974 * Merged theories IntDef, Numeral and IntArith into unified theory
   975 Int.  INCOMPATIBILITY.
   976 
   977 * Theory Library/Code_Index: type "index" now represents natural
   978 numbers rather than integers.  INCOMPATIBILITY.
   979 
   980 * New class "uminus" with operation "uminus" (split of from class
   981 "minus" which now only has operation "minus", binary).
   982 INCOMPATIBILITY.
   983 
   984 * Constants "card", "internal_split", "option_map" now with authentic
   985 syntax.  INCOMPATIBILITY.
   986 
   987 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
   988 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
   989 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
   990 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
   991 Sup_set_def, le_def, less_def, option_map_def now with object
   992 equality.  INCOMPATIBILITY.
   993 
   994 * Records. Removed K_record, and replaced it by pure lambda term
   995 %x. c. The simplifier setup is now more robust against eta expansion.
   996 INCOMPATIBILITY: in cases explicitly referring to K_record.
   997 
   998 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
   999 
  1000 * Library/ListVector: new theory of arithmetic vector operations.
  1001 
  1002 * Library/Order_Relation: new theory of various orderings as sets of
  1003 pairs.  Defines preorders, partial orders, linear orders and
  1004 well-orders on sets and on types.
  1005 
  1006 
  1007 *** ZF ***
  1008 
  1009 * Renamed some theories to allow to loading both ZF and HOL in the
  1010 same session:
  1011 
  1012   Datatype  -> Datatype_ZF
  1013   Inductive -> Inductive_ZF
  1014   Int       -> Int_ZF
  1015   IntDiv    -> IntDiv_ZF
  1016   Nat       -> Nat_ZF
  1017   List      -> List_ZF
  1018   Main      -> Main_ZF
  1019 
  1020 INCOMPATIBILITY: ZF theories that import individual theories below
  1021 Main might need to be adapted.  Regular theory Main is still
  1022 available, as trivial extension of Main_ZF.
  1023 
  1024 
  1025 *** ML ***
  1026 
  1027 * ML within Isar: antiquotation @{const name} or @{const
  1028 name(typargs)} produces statically-checked Const term.
  1029 
  1030 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1031 (of the same name).  Removed obsolete print command.
  1032 
  1033 * Removed obsolete "use_legacy_bindings" function.
  1034 
  1035 * The ``print mode'' is now a thread-local value derived from a global
  1036 template (the former print_mode reference), thus access becomes
  1037 non-critical.  The global print_mode reference is for session
  1038 management only; user-code should use print_mode_value,
  1039 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1040 
  1041 * Functions system/system_out provide a robust way to invoke external
  1042 shell commands, with propagation of interrupts (requires Poly/ML
  1043 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1044 
  1045 
  1046 *** System ***
  1047 
  1048 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1049 in accordance with Proof General 3.7, which prefers GNU emacs.
  1050 
  1051 * isatool tty runs Isabelle process with plain tty interaction;
  1052 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1053 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1054 
  1055 * isatool browser now works with Cygwin as well, using general
  1056 "javapath" function defined in Isabelle process environment.
  1057 
  1058 * YXML notation provides a simple and efficient alternative to
  1059 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1060 isatool yxml as described in the Isabelle system manual.
  1061 
  1062 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1063 provides general wrapper for managing an Isabelle process in a robust
  1064 fashion, with ``cooked'' output from stdin/stderr.
  1065 
  1066 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1067 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1068 
  1069 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1070 way of changing the user's settings is via
  1071 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1072 script.
  1073 
  1074 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1075 cores of the underlying machine, which is a good starting point for
  1076 optimal performance tuning.  The corresponding usedir option -M allows
  1077 "max" as an alias for "0".  WARNING: does not work on certain versions
  1078 of Mac OS (with Poly/ML 5.1).
  1079 
  1080 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1081 adverse effect of Isabelle flooding interactive front-ends (notably
  1082 ProofGeneral / XEmacs).
  1083 
  1084 
  1085 
  1086 New in Isabelle2007 (November 2007)
  1087 -----------------------------------
  1088 
  1089 *** General ***
  1090 
  1091 * More uniform information about legacy features, notably a
  1092 warning/error of "Legacy feature: ...", depending on the state of the
  1093 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1094 legacy features will disappear eventually.
  1095 
  1096 * Theory syntax: the header format ``theory A = B + C:'' has been
  1097 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1098 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1099 
  1100 * Theory syntax: the old non-Isar theory file format has been
  1101 discontinued altogether.  Note that ML proof scripts may still be used
  1102 with Isar theories; migration is usually quite simple with the ML
  1103 function use_legacy_bindings.  INCOMPATIBILITY.
  1104 
  1105 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1106 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1107 quotes.
  1108 
  1109 * Theory loader: be more serious about observing the static theory
  1110 header specifications (including optional directories), but not the
  1111 accidental file locations of previously successful loads.  The strict
  1112 update policy of former update_thy is now already performed by
  1113 use_thy, so the former has been removed; use_thys updates several
  1114 theories simultaneously, just as 'imports' within a theory header
  1115 specification, but without merging the results.  Potential
  1116 INCOMPATIBILITY: may need to refine theory headers and commands
  1117 ROOT.ML which depend on load order.
  1118 
  1119 * Theory loader: optional support for content-based file
  1120 identification, instead of the traditional scheme of full physical
  1121 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1122 (cf. the system manual).  The new scheme allows to work with
  1123 non-finished theories in persistent session images, such that source
  1124 files may be moved later on without requiring reloads.
  1125 
  1126 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1127 file (with the same base name as the theory) are considered a legacy
  1128 feature, which will disappear eventually. Even now, the theory loader
  1129 no longer maintains dependencies on such files.
  1130 
  1131 * Syntax: the scope for resolving ambiguities via type-inference is
  1132 now limited to individual terms, instead of whole simultaneous
  1133 specifications as before. This greatly reduces the complexity of the
  1134 syntax module and improves flexibility by separating parsing and
  1135 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1136 'fixes' etc.) are required in rare situations.
  1137 
  1138 * Syntax: constants introduced by new-style packages ('definition',
  1139 'abbreviation' etc.) are passed through the syntax module in
  1140 ``authentic mode''. This means that associated mixfix annotations
  1141 really stick to such constants, independently of potential name space
  1142 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1143 trees are represented slightly differently, may need to adapt syntax
  1144 translations accordingly. Use CONST marker in 'translations' and
  1145 @{const_syntax} antiquotation in 'parse_translation' etc.
  1146 
  1147 * Legacy goal package: reduced interface to the bare minimum required
  1148 to keep existing proof scripts running.  Most other user-level
  1149 functions are now part of the OldGoals structure, which is *not* open
  1150 by default (consider isatool expandshort before open OldGoals).
  1151 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1152 these tend to cause confusion about the actual goal (!) context being
  1153 used here, which is not necessarily the same as the_context().
  1154 
  1155 * Command 'find_theorems': supports "*" wild-card in "name:"
  1156 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1157 support a specific search form (see ProofGeneral/CHANGES).
  1158 
  1159 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1160 by default, which means that "prems" (and also "fixed variables") are
  1161 suppressed from proof state output.  Note that the ProofGeneral
  1162 settings mechanism allows to change and save options persistently, but
  1163 older versions of Isabelle will fail to start up if a negative prems
  1164 limit is imposed.
  1165 
  1166 * Local theory targets may be specified by non-nested blocks of
  1167 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1168 contain definitions, theorems etc., including any derived mechanism
  1169 that has been implemented on top of these primitives.  This concept
  1170 generalizes the existing ``theorem (in ...)'' towards more versatility
  1171 and scalability.
  1172 
  1173 * Proof General interface: proper undo of final 'end' command;
  1174 discontinued Isabelle/classic mode (ML proof scripts).
  1175 
  1176 
  1177 *** Document preparation ***
  1178 
  1179 * Added antiquotation @{theory name} which prints the given name,
  1180 after checking that it refers to a valid ancestor theory in the
  1181 current context.
  1182 
  1183 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1184 check the given source text as ML type/structure, printing verbatim.
  1185 
  1186 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1187 "c args == rhs" given in the current context.  (Any number of
  1188 arguments may be given on the LHS.)
  1189 
  1190 
  1191 *** Pure ***
  1192 
  1193 * The 'class' package offers a combination of axclass and locale to
  1194 achieve Haskell-like type classes in Isabelle.  Definitions and
  1195 theorems within a class context produce both relative results (with
  1196 implicit parameters according to the locale context), and polymorphic
  1197 constants with qualified polymorphism (according to the class
  1198 context).  Within the body context of a 'class' target, a separate
  1199 syntax layer ("user space type system") takes care of converting
  1200 between global polymorphic consts and internal locale representation.
  1201 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1202 "isatool doc classes" provides a tutorial.
  1203 
  1204 * Generic code generator framework allows to generate executable
  1205 code for ML and Haskell (including Isabelle classes).  A short usage
  1206 sketch:
  1207 
  1208     internal compilation:
  1209         export_code <list of constants (term syntax)> in SML
  1210     writing SML code to a file:
  1211         export_code <list of constants (term syntax)> in SML <filename>
  1212     writing OCaml code to a file:
  1213         export_code <list of constants (term syntax)> in OCaml <filename>
  1214     writing Haskell code to a bunch of files:
  1215         export_code <list of constants (term syntax)> in Haskell <filename>
  1216 
  1217     evaluating closed propositions to True/False using code generation:
  1218         method ``eval''
  1219 
  1220 Reasonable default setup of framework in HOL.
  1221 
  1222 Theorem attributs for selecting and transforming function equations theorems:
  1223 
  1224     [code fun]:        select a theorem as function equation for a specific constant
  1225     [code fun del]:    deselect a theorem as function equation for a specific constant
  1226     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1227     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1228 
  1229 User-defined serializations (target in {SML, OCaml, Haskell}):
  1230 
  1231     code_const <and-list of constants (term syntax)>
  1232       {(target) <and-list of const target syntax>}+
  1233 
  1234     code_type <and-list of type constructors>
  1235       {(target) <and-list of type target syntax>}+
  1236 
  1237     code_instance <and-list of instances>
  1238       {(target)}+
  1239         where instance ::= <type constructor> :: <class>
  1240 
  1241     code_class <and_list of classes>
  1242       {(target) <and-list of class target syntax>}+
  1243         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1244 
  1245 code_instance and code_class only are effective to target Haskell.
  1246 
  1247 For example usage see src/HOL/ex/Codegenerator.thy and
  1248 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1249 generation from Isabelle/HOL theories is available via "isatool doc
  1250 codegen".
  1251 
  1252 * Code generator: consts in 'consts_code' Isar commands are now
  1253 referred to by usual term syntax (including optional type
  1254 annotations).
  1255 
  1256 * Command 'no_translations' removes translation rules from theory
  1257 syntax.
  1258 
  1259 * Overloaded definitions are now actually checked for acyclic
  1260 dependencies.  The overloading scheme is slightly more general than
  1261 that of Haskell98, although Isabelle does not demand an exact
  1262 correspondence to type class and instance declarations.
  1263 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1264 exotic versions of overloading -- at the discretion of the user!
  1265 
  1266 Polymorphic constants are represented via type arguments, i.e. the
  1267 instantiation that matches an instance against the most general
  1268 declaration given in the signature.  For example, with the declaration
  1269 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1270 as c(nat).  Overloading is essentially simultaneous structural
  1271 recursion over such type arguments.  Incomplete specification patterns
  1272 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1273 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1274 Command 'print_theory' outputs the normalized system of recursive
  1275 equations, see section "definitions".
  1276 
  1277 * Configuration options are maintained within the theory or proof
  1278 context (with name and type bool/int/string), providing a very simple
  1279 interface to a poor-man's version of general context data.  Tools may
  1280 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1281 these values using Config.get etc.  Users may change options via an
  1282 associated attribute of the same name.  This form of context
  1283 declaration works particularly well with commands 'declare' or
  1284 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1285 very easy to avoid global references, which would not observe Isar
  1286 toplevel undo/redo and fail to work with multithreading.
  1287 
  1288 Various global ML references of Pure and HOL have been turned into
  1289 configuration options:
  1290 
  1291   Unify.search_bound		unify_search_bound
  1292   Unify.trace_bound		unify_trace_bound
  1293   Unify.trace_simp		unify_trace_simp
  1294   Unify.trace_types		unify_trace_types
  1295   Simplifier.simp_depth_limit	simp_depth_limit
  1296   Blast.depth_limit		blast_depth_limit
  1297   DatatypeProp.dtK		datatype_distinctness_limit
  1298   fast_arith_neq_limit  	fast_arith_neq_limit
  1299   fast_arith_split_limit	fast_arith_split_limit
  1300 
  1301 * Named collections of theorems may be easily installed as context
  1302 data using the functor NamedThmsFun (see also
  1303 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1304 attributes; there is also a toplevel print command.  This facility is
  1305 just a common case of general context data, which is the preferred way
  1306 for anything more complex than just a list of facts in canonical
  1307 order.
  1308 
  1309 * Isar: command 'declaration' augments a local theory by generic
  1310 declaration functions written in ML.  This enables arbitrary content
  1311 being added to the context, depending on a morphism that tells the
  1312 difference of the original declaration context wrt. the application
  1313 context encountered later on.
  1314 
  1315 * Isar: proper interfaces for simplification procedures.  Command
  1316 'simproc_setup' declares named simprocs (with match patterns, and body
  1317 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1318 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1319 
  1320 * Isar: an extra pair of brackets around attribute declarations
  1321 abbreviates a theorem reference involving an internal dummy fact,
  1322 which will be ignored later --- only the effect of the attribute on
  1323 the background context will persist.  This form of in-place
  1324 declarations is particularly useful with commands like 'declare' and
  1325 'using', for example ``have A using [[simproc a]] by simp''.
  1326 
  1327 * Isar: method "assumption" (and implicit closing of subproofs) now
  1328 takes simple non-atomic goal assumptions into account: after applying
  1329 an assumption as a rule the resulting subgoals are solved by atomic
  1330 assumption steps.  This is particularly useful to finish 'obtain'
  1331 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1332 without referring to the original premise "!!x. P x ==> thesis" in the
  1333 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1334 more permissive.
  1335 
  1336 * Isar: implicit use of prems from the Isar proof context is
  1337 considered a legacy feature.  Common applications like ``have A .''
  1338 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1339 referencing facts explicitly here improves readability and
  1340 maintainability of proof texts.
  1341 
  1342 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1343 the obtained context from the course of reasoning!  For example:
  1344 
  1345   assume "EX x y. A x & B y"   -- "any previous fact"
  1346   then guess x and y by clarify
  1347 
  1348 This technique is potentially adventurous, depending on the facts and
  1349 proof tools being involved here.
  1350 
  1351 * Isar: known facts from the proof context may be specified as literal
  1352 propositions, using ASCII back-quote syntax.  This works wherever
  1353 named facts used to be allowed so far, in proof commands, proof
  1354 methods, attributes etc.  Literal facts are retrieved from the context
  1355 according to unification of type and term parameters.  For example,
  1356 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1357 theorems in the current context, then these are valid literal facts:
  1358 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1359 
  1360 There is also a proof method "fact" which does the same composition
  1361 for explicit goal states, e.g. the following proof texts coincide with
  1362 certain special cases of literal facts:
  1363 
  1364   have "A" by fact                 ==  note `A`
  1365   have "A ==> B" by fact           ==  note `A ==> B`
  1366   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1367   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1368 
  1369 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1370 outer syntax.  Thus symbolic identifiers may be used without
  1371 additional white space in declarations like this: ``assume *: A''.
  1372 
  1373 * Isar: 'print_facts' prints all local facts of the current context,
  1374 both named and unnamed ones.
  1375 
  1376 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1377 
  1378   def x == "t" and y == "u"
  1379 
  1380 * Isar: added command 'unfolding', which is structurally similar to
  1381 'using', but affects both the goal state and facts by unfolding given
  1382 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1383 'unfolded' attribute may be replaced by first-class proof text.
  1384 
  1385 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1386 and command 'unfolding' now all support object-level equalities
  1387 (potentially conditional).  The underlying notion of rewrite rule is
  1388 analogous to the 'rule_format' attribute, but *not* that of the
  1389 Simplifier (which is usually more generous).
  1390 
  1391 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1392 premises of a theorem by n. Useful in conjunction with drule.
  1393 
  1394 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1395 method expression within a sandbox consisting of the first N
  1396 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1397 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1398 simplifies all new goals that emerge from applying rule foo to the
  1399 originally first one.
  1400 
  1401 * Isar: schematic goals are no longer restricted to higher-order
  1402 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1403 expected.
  1404 
  1405 * Isar: the conclusion of a long theorem statement is now either
  1406 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1407 (essentially a disjunction of cases with local parameters and
  1408 assumptions).  The latter allows to express general elimination rules
  1409 adequately; in this notation common elimination rules look like this:
  1410 
  1411   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1412     assumes "EX x. P x"
  1413     obtains x where "P x"
  1414 
  1415   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1416     assumes "A & B"
  1417     obtains A and B
  1418 
  1419   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1420     assumes "A | B"
  1421     obtains
  1422       A
  1423     | B
  1424 
  1425 The subsequent classical rules even refer to the formal "thesis"
  1426 explicitly:
  1427 
  1428   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1429     obtains "~ thesis"
  1430 
  1431   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1432     obtains "thesis ==> something"
  1433 
  1434 The actual proof of an 'obtains' statement is analogous to that of the
  1435 Isar proof element 'obtain', only that there may be several cases.
  1436 Optional case names may be specified in parentheses; these will be
  1437 available both in the present proof and as annotations in the
  1438 resulting rule, for later use with the 'cases' method (cf. attribute
  1439 case_names).
  1440 
  1441 * Isar: the assumptions of a long theorem statement are available as
  1442 "assms" fact in the proof context.  This is more appropriate than the
  1443 (historical) "prems", which refers to all assumptions of the current
  1444 context, including those from the target locale, proof body etc.
  1445 
  1446 * Isar: 'print_statement' prints theorems from the current theory or
  1447 proof context in long statement form, according to the syntax of a
  1448 top-level lemma.
  1449 
  1450 * Isar: 'obtain' takes an optional case name for the local context
  1451 introduction rule (default "that").
  1452 
  1453 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1454 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1455 to occur.
  1456 
  1457 * Pure: syntax "CONST name" produces a fully internalized constant
  1458 according to the current context.  This is particularly useful for
  1459 syntax translations that should refer to internal constant
  1460 representations independently of name spaces.
  1461 
  1462 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1463 instead of "FOO ". This allows multiple binder declarations to coexist
  1464 in the same context.  INCOMPATIBILITY.
  1465 
  1466 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1467 primitive that also works in a locale context (both for constants and
  1468 fixed variables). Type declaration and internal syntactic representation
  1469 of given constants retrieved from the context. Likewise, the
  1470 'no_notation' command allows to remove given syntax annotations from the
  1471 current context.
  1472 
  1473 * Isar/locales: new derived specification elements 'axiomatization',
  1474 'definition', 'abbreviation', which support type-inference, admit
  1475 object-level specifications (equality, equivalence).  See also the
  1476 isar-ref manual.  Examples:
  1477 
  1478   axiomatization
  1479     eq  (infix "===" 50) where
  1480     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1481 
  1482   definition "f x y = x + y + 1"
  1483   definition g where "g x = f x x"
  1484 
  1485   abbreviation
  1486     neq  (infix "=!=" 50) where
  1487     "x =!= y == ~ (x === y)"
  1488 
  1489 These specifications may be also used in a locale context.  Then the
  1490 constants being introduced depend on certain fixed parameters, and the
  1491 constant name is qualified by the locale base name.  An internal
  1492 abbreviation takes care for convenient input and output, making the
  1493 parameters implicit and using the original short name.  See also
  1494 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1495 entities from a monomorphic theory.
  1496 
  1497 Presently, abbreviations are only available 'in' a target locale, but
  1498 not inherited by general import expressions.  Also note that
  1499 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1500 'translations' in common applications.  The "no_abbrevs" print mode
  1501 prevents folding of abbreviations in term output.
  1502 
  1503 Concrete syntax is attached to specified constants in internal form,
  1504 independently of name spaces.  The parse tree representation is
  1505 slightly different -- use 'notation' instead of raw 'syntax', and
  1506 'translations' with explicit "CONST" markup to accommodate this.
  1507 
  1508 * Pure/Isar: unified syntax for new-style specification mechanisms
  1509 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1510 full type inference and dummy patterns ("_").  For example:
  1511 
  1512   definition "K x _ = x"
  1513 
  1514   inductive conj for A B
  1515   where "A ==> B ==> conj A B"
  1516 
  1517 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1518 the current context.  Print mode "no_abbrevs" prevents inversion of
  1519 abbreviations on output.
  1520 
  1521 * Isar/locales: improved parameter handling: use of locales "var" and
  1522 "struct" no longer necessary; - parameter renamings are no longer
  1523 required to be injective.  For example, this allows to define
  1524 endomorphisms as locale endom = homom mult mult h.
  1525 
  1526 * Isar/locales: changed the way locales with predicates are defined.
  1527 Instead of accumulating the specification, the imported expression is
  1528 now an interpretation.  INCOMPATIBILITY: different normal form of
  1529 locale expressions.  In particular, in interpretations of locales with
  1530 predicates, goals repesenting already interpreted fragments are not
  1531 removed automatically.  Use methods `intro_locales' and
  1532 `unfold_locales'; see below.
  1533 
  1534 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1535 provide backward reasoning on locales predicates.  The methods are
  1536 aware of interpretations and discharge corresponding goals.
  1537 `intro_locales' is less aggressive then `unfold_locales' and does not
  1538 unfold predicates to assumptions.
  1539 
  1540 * Isar/locales: the order in which locale fragments are accumulated
  1541 has changed.  This enables to override declarations from fragments due
  1542 to interpretations -- for example, unwanted simp rules.
  1543 
  1544 * Isar/locales: interpretation in theories and proof contexts has been
  1545 extended.  One may now specify (and prove) equations, which are
  1546 unfolded in interpreted theorems.  This is useful for replacing
  1547 defined concepts (constants depending on locale parameters) by
  1548 concepts already existing in the target context.  Example:
  1549 
  1550   interpretation partial_order ["op <= :: [int, int] => bool"]
  1551     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1552 
  1553 Typically, the constant `partial_order.less' is created by a
  1554 definition specification element in the context of locale
  1555 partial_order.
  1556 
  1557 * Method "induct": improved internal context management to support
  1558 local fixes and defines on-the-fly. Thus explicit meta-level
  1559 connectives !!  and ==> are rarely required anymore in inductive goals
  1560 (using object-logic connectives for this purpose has been long
  1561 obsolete anyway). Common proof patterns are explained in
  1562 src/HOL/Induct/Common_Patterns.thy, see also
  1563 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1564 examples.
  1565 
  1566 * Method "induct": improved handling of simultaneous goals. Instead of
  1567 introducing object-level conjunction, the statement is now split into
  1568 several conclusions, while the corresponding symbolic cases are nested
  1569 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1570 see src/HOL/Induct/Common_Patterns.thy, for example.
  1571 
  1572 * Method "induct": mutual induction rules are now specified as a list
  1573 of rule sharing the same induction cases. HOL packages usually provide
  1574 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1575 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1576 mutual induction rules differently, i.e. like this:
  1577 
  1578   (induct rule: foo_bar.inducts)
  1579   (induct set: foo bar)
  1580   (induct pred: foo bar)
  1581   (induct type: foo bar)
  1582 
  1583 The ML function ProjectRule.projections turns old-style rules into the
  1584 new format.
  1585 
  1586 * Method "coinduct": dual of induction, see
  1587 src/HOL/Library/Coinductive_List.thy for various examples.
  1588 
  1589 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1590 considered a legacy feature.
  1591 
  1592 * Attribute "symmetric" produces result with standardized schematic
  1593 variables (index 0).  Potential INCOMPATIBILITY.
  1594 
  1595 * Simplifier: by default the simplifier trace only shows top level
  1596 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1597 default. Thus there is less danger of being flooded by the trace. The
  1598 trace indicates where parts have been suppressed.
  1599   
  1600 * Provers/classical: removed obsolete classical version of elim_format
  1601 attribute; classical elim/dest rules are now treated uniformly when
  1602 manipulating the claset.
  1603 
  1604 * Provers/classical: stricter checks to ensure that supplied intro,
  1605 dest and elim rules are well-formed; dest and elim rules must have at
  1606 least one premise.
  1607 
  1608 * Provers/classical: attributes dest/elim/intro take an optional
  1609 weight argument for the rule (just as the Pure versions).  Weights are
  1610 ignored by automated tools, but determine the search order of single
  1611 rule steps.
  1612 
  1613 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1614 where the body does not mention the bound variable.  Note that dummy
  1615 patterns implicitly depend on their context of bounds, which makes
  1616 "{_. _}" match any set comprehension as expected.  Potential
  1617 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1618 constant "_idtdummy" in the binding position.
  1619 
  1620 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1621 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1622 for example "A -> B" => "Pi A (%_. B)".
  1623 
  1624 * Pure: 'class_deps' command visualizes the subclass relation, using
  1625 the graph browser tool.
  1626 
  1627 * Pure: 'print_theory' now suppresses certain internal declarations by
  1628 default; use '!' option for full details.
  1629 
  1630 
  1631 *** HOL ***
  1632 
  1633 * Method "metis" proves goals by applying the Metis general-purpose
  1634 resolution prover (see also http://gilith.com/software/metis/).
  1635 Examples are in the directory MetisExamples.  WARNING: the
  1636 Isabelle/HOL-Metis integration does not yet work properly with
  1637 multi-threading.
  1638   
  1639 * Command 'sledgehammer' invokes external automatic theorem provers as
  1640 background processes.  It generates calls to the "metis" method if
  1641 successful. These can be pasted into the proof.  Users do not have to
  1642 wait for the automatic provers to return.  WARNING: does not really
  1643 work with multi-threading.
  1644 
  1645 * New "auto_quickcheck" feature tests outermost goal statements for
  1646 potential counter-examples.  Controlled by ML references
  1647 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1648 5000 milliseconds).  Fails silently if statements is outside of
  1649 executable fragment, or any other codgenerator problem occurs.
  1650 
  1651 * New constant "undefined" with axiom "undefined x = undefined".
  1652 
  1653 * Added class "HOL.eq", allowing for code generation with polymorphic
  1654 equality.
  1655 
  1656 * Some renaming of class constants due to canonical name prefixing in
  1657 the new 'class' package:
  1658 
  1659     HOL.abs ~> HOL.abs_class.abs
  1660     HOL.divide ~> HOL.divide_class.divide
  1661     0 ~> HOL.zero_class.zero
  1662     1 ~> HOL.one_class.one
  1663     op + ~> HOL.plus_class.plus
  1664     op - ~> HOL.minus_class.minus
  1665     uminus ~> HOL.minus_class.uminus
  1666     op * ~> HOL.times_class.times
  1667     op < ~> HOL.ord_class.less
  1668     op <= > HOL.ord_class.less_eq
  1669     Nat.power ~> Power.power_class.power
  1670     Nat.size ~> Nat.size_class.size
  1671     Numeral.number_of ~> Numeral.number_class.number_of
  1672     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1673     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1674     Orderings.min ~> Orderings.ord_class.min
  1675     Orderings.max ~> Orderings.ord_class.max
  1676     Divides.op div ~> Divides.div_class.div
  1677     Divides.op mod ~> Divides.div_class.mod
  1678     Divides.op dvd ~> Divides.div_class.dvd
  1679 
  1680 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1681 
  1682 a) User-defined constants using any of the names "plus", "minus",
  1683 "times", "less" or "less_eq". The standard syntax translations for
  1684 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1685 names.
  1686 
  1687 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1688 INCOMPATIBILITY: use more specific names.
  1689 
  1690 c) Permutative equations (e.g. "a + b = b + a")
  1691 Since the change of names also changes the order of terms, permutative
  1692 rewrite rules may get applied in a different order. Experience shows
  1693 that this is rarely the case (only two adaptions in the whole Isabelle
  1694 distribution).  INCOMPATIBILITY: rewrite proofs
  1695 
  1696 d) ML code directly refering to constant names
  1697 This in general only affects hand-written proof tactics, simprocs and
  1698 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1699 Consider using @{const_name} antiquotation.
  1700 
  1701 * New class "default" with associated constant "default".
  1702 
  1703 * Function "sgn" is now overloaded and available on int, real, complex
  1704 (and other numeric types), using class "sgn".  Two possible defs of
  1705 sgn are given as equational assumptions in the classes sgn_if and
  1706 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1707 INCOMPATIBILITY.
  1708 
  1709 * Locale "partial_order" now unified with class "order" (cf. theory
  1710 Orderings), added parameter "less".  INCOMPATIBILITY.
  1711 
  1712 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1713 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1714 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1715 
  1716 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1717 changed order of proof goals in instance proofs.
  1718 
  1719 * The transitivity reasoner for partial and linear orders is set up
  1720 for classes "order" and "linorder".  Instances of the reasoner are available
  1721 in all contexts importing or interpreting the corresponding locales.
  1722 Method "order" invokes the reasoner separately; the reasoner
  1723 is also integrated with the Simplifier as a solver.  Diagnostic
  1724 command 'print_orders' shows the available instances of the reasoner
  1725 in the current context.
  1726 
  1727 * Localized monotonicity predicate in theory "Orderings"; integrated
  1728 lemmas max_of_mono and min_of_mono with this predicate.
  1729 INCOMPATIBILITY.
  1730 
  1731 * Formulation of theorem "dense" changed slightly due to integration
  1732 with new class dense_linear_order.
  1733 
  1734 * Uniform lattice theory development in HOL.
  1735 
  1736     constants "meet" and "join" now named "inf" and "sup"
  1737     constant "Meet" now named "Inf"
  1738 
  1739     classes "meet_semilorder" and "join_semilorder" now named
  1740       "lower_semilattice" and "upper_semilattice"
  1741     class "lorder" now named "lattice"
  1742     class "comp_lat" now named "complete_lattice"
  1743 
  1744     Instantiation of lattice classes allows explicit definitions
  1745     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1746 
  1747   INCOMPATIBILITY.  Theorem renames:
  1748 
  1749     meet_left_le            ~> inf_le1
  1750     meet_right_le           ~> inf_le2
  1751     join_left_le            ~> sup_ge1
  1752     join_right_le           ~> sup_ge2
  1753     meet_join_le            ~> inf_sup_ord
  1754     le_meetI                ~> le_infI
  1755     join_leI                ~> le_supI
  1756     le_meet                 ~> le_inf_iff
  1757     le_join                 ~> ge_sup_conv
  1758     meet_idempotent         ~> inf_idem
  1759     join_idempotent         ~> sup_idem
  1760     meet_comm               ~> inf_commute
  1761     join_comm               ~> sup_commute
  1762     meet_leI1               ~> le_infI1
  1763     meet_leI2               ~> le_infI2
  1764     le_joinI1               ~> le_supI1
  1765     le_joinI2               ~> le_supI2
  1766     meet_assoc              ~> inf_assoc
  1767     join_assoc              ~> sup_assoc
  1768     meet_left_comm          ~> inf_left_commute
  1769     meet_left_idempotent    ~> inf_left_idem
  1770     join_left_comm          ~> sup_left_commute
  1771     join_left_idempotent    ~> sup_left_idem
  1772     meet_aci                ~> inf_aci
  1773     join_aci                ~> sup_aci
  1774     le_def_meet             ~> le_iff_inf
  1775     le_def_join             ~> le_iff_sup
  1776     join_absorp2            ~> sup_absorb2
  1777     join_absorp1            ~> sup_absorb1
  1778     meet_absorp1            ~> inf_absorb1
  1779     meet_absorp2            ~> inf_absorb2
  1780     meet_join_absorp        ~> inf_sup_absorb
  1781     join_meet_absorp        ~> sup_inf_absorb
  1782     distrib_join_le         ~> distrib_sup_le
  1783     distrib_meet_le         ~> distrib_inf_le
  1784 
  1785     add_meet_distrib_left   ~> add_inf_distrib_left
  1786     add_join_distrib_left   ~> add_sup_distrib_left
  1787     is_join_neg_meet        ~> is_join_neg_inf
  1788     is_meet_neg_join        ~> is_meet_neg_sup
  1789     add_meet_distrib_right  ~> add_inf_distrib_right
  1790     add_join_distrib_right  ~> add_sup_distrib_right
  1791     add_meet_join_distribs  ~> add_sup_inf_distribs
  1792     join_eq_neg_meet        ~> sup_eq_neg_inf
  1793     meet_eq_neg_join        ~> inf_eq_neg_sup
  1794     add_eq_meet_join        ~> add_eq_inf_sup
  1795     meet_0_imp_0            ~> inf_0_imp_0
  1796     join_0_imp_0            ~> sup_0_imp_0
  1797     meet_0_eq_0             ~> inf_0_eq_0
  1798     join_0_eq_0             ~> sup_0_eq_0
  1799     neg_meet_eq_join        ~> neg_inf_eq_sup
  1800     neg_join_eq_meet        ~> neg_sup_eq_inf
  1801     join_eq_if              ~> sup_eq_if
  1802 
  1803     mono_meet               ~> mono_inf
  1804     mono_join               ~> mono_sup
  1805     meet_bool_eq            ~> inf_bool_eq
  1806     join_bool_eq            ~> sup_bool_eq
  1807     meet_fun_eq             ~> inf_fun_eq
  1808     join_fun_eq             ~> sup_fun_eq
  1809     meet_set_eq             ~> inf_set_eq
  1810     join_set_eq             ~> sup_set_eq
  1811     meet1_iff               ~> inf1_iff
  1812     meet2_iff               ~> inf2_iff
  1813     meet1I                  ~> inf1I
  1814     meet2I                  ~> inf2I
  1815     meet1D1                 ~> inf1D1
  1816     meet2D1                 ~> inf2D1
  1817     meet1D2                 ~> inf1D2
  1818     meet2D2                 ~> inf2D2
  1819     meet1E                  ~> inf1E
  1820     meet2E                  ~> inf2E
  1821     join1_iff               ~> sup1_iff
  1822     join2_iff               ~> sup2_iff
  1823     join1I1                 ~> sup1I1
  1824     join2I1                 ~> sup2I1
  1825     join1I1                 ~> sup1I1
  1826     join2I2                 ~> sup1I2
  1827     join1CI                 ~> sup1CI
  1828     join2CI                 ~> sup2CI
  1829     join1E                  ~> sup1E
  1830     join2E                  ~> sup2E
  1831 
  1832     is_meet_Meet            ~> is_meet_Inf
  1833     Meet_bool_def           ~> Inf_bool_def
  1834     Meet_fun_def            ~> Inf_fun_def
  1835     Meet_greatest           ~> Inf_greatest
  1836     Meet_lower              ~> Inf_lower
  1837     Meet_set_def            ~> Inf_set_def
  1838 
  1839     Sup_def                 ~> Sup_Inf
  1840     Sup_bool_eq             ~> Sup_bool_def
  1841     Sup_fun_eq              ~> Sup_fun_def
  1842     Sup_set_eq              ~> Sup_set_def
  1843 
  1844     listsp_meetI            ~> listsp_infI
  1845     listsp_meet_eq          ~> listsp_inf_eq
  1846 
  1847     meet_min                ~> inf_min
  1848     join_max                ~> sup_max
  1849 
  1850 * Added syntactic class "size"; overloaded constant "size" now has
  1851 type "'a::size ==> bool"
  1852 
  1853 * Internal reorganisation of `size' of datatypes: size theorems
  1854 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1855 simplification rules by default!); theorems "prod.size" now named
  1856 "*.size".
  1857 
  1858 * Class "div" now inherits from class "times" rather than "type".
  1859 INCOMPATIBILITY.
  1860 
  1861 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1862 Linorder etc.  have disappeared; operations defined in terms of
  1863 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1864 
  1865 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1866 
  1867 * HOL-Word: New extensive library and type for generic, fixed size
  1868 machine words, with arithemtic, bit-wise, shifting and rotating
  1869 operations, reflection into int, nat, and bool lists, automation for
  1870 linear arithmetic (by automatic reflection into nat or int), including
  1871 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1872 arithmetic type classes, supporting automatic simplification of
  1873 numerals on all operations.
  1874 
  1875 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1876 
  1877 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1878 
  1879 * Code generator library theories:
  1880   - Code_Integer represents HOL integers by big integer literals in target
  1881     languages.
  1882   - Code_Char represents HOL characters by character literals in target
  1883     languages.
  1884   - Code_Char_chr like Code_Char, but also offers treatment of character
  1885     codes; includes Code_Integer.
  1886   - Executable_Set allows to generate code for finite sets using lists.
  1887   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1888     denominator).
  1889   - Executable_Real implements a subset of real numbers, namly those
  1890     representable by rational numbers.
  1891   - Efficient_Nat implements natural numbers by integers, which in general will
  1892     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1893     includes Code_Integer.
  1894   - Code_Index provides an additional datatype index which is mapped to
  1895     target-language built-in integers.
  1896   - Code_Message provides an additional datatype message_string which is isomorphic to
  1897     strings; messages are mapped to target-language strings.
  1898 
  1899 * New package for inductive predicates
  1900 
  1901   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1902 
  1903     inductive
  1904       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1905       for z_1 :: U_1 and ... and z_n :: U_m
  1906     where
  1907       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1908     | ...
  1909 
  1910   with full support for type-inference, rather than
  1911 
  1912     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1913 
  1914     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1915     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1916 
  1917     inductive "s z_1 ... z_m"
  1918     intros
  1919       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1920       ...
  1921 
  1922   For backward compatibility, there is a wrapper allowing inductive
  1923   sets to be defined with the new package via
  1924 
  1925     inductive_set
  1926       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1927       for z_1 :: U_1 and ... and z_n :: U_m
  1928     where
  1929       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1930     | ...
  1931 
  1932   or
  1933 
  1934     inductive_set
  1935       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1936       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1937       for z_1 :: U_1 and ... and z_n :: U_m
  1938     where
  1939       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1940     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1941     | ...
  1942 
  1943   if the additional syntax "p ..." is required.
  1944 
  1945   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1946   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1947 
  1948   INCOMPATIBILITIES:
  1949 
  1950   - Since declaration and definition of inductive sets or predicates
  1951     is no longer separated, abbreviations involving the newly
  1952     introduced sets or predicates must be specified together with the
  1953     introduction rules after the 'where' keyword (see above), rather
  1954     than before the actual inductive definition.
  1955 
  1956   - The variables in induction and elimination rules are now
  1957     quantified in the order of their occurrence in the introduction
  1958     rules, rather than in alphabetical order. Since this may break
  1959     some proofs, these proofs either have to be repaired, e.g. by
  1960     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1961     statements of the form
  1962 
  1963       case (rule_i a_i_1 ... a_i_{k_i})
  1964 
  1965     or the old order of quantification has to be restored by explicitly adding
  1966     meta-level quantifiers in the introduction rules, i.e.
  1967 
  1968       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  1969 
  1970   - The format of the elimination rules is now
  1971 
  1972       p z_1 ... z_m x_1 ... x_n ==>
  1973         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1974         ==> ... ==> P
  1975 
  1976     for predicates and
  1977 
  1978       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1979         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1980         ==> ... ==> P
  1981 
  1982     for sets rather than
  1983 
  1984       x : s z_1 ... z_m ==>
  1985         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1986         ==> ... ==> P
  1987 
  1988     This may require terms in goals to be expanded to n-tuples
  1989     (e.g. using case_tac or simplification with the split_paired_all
  1990     rule) before the above elimination rule is applicable.
  1991 
  1992   - The elimination or case analysis rules for (mutually) inductive
  1993     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1994     list of rules "p_1_..._p_k.elims" is no longer available.
  1995 
  1996 * New package "function"/"fun" for general recursive functions,
  1997 supporting mutual and nested recursion, definitions in local contexts,
  1998 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1999 for small examples, and the separate tutorial on the function
  2000 package. The old recdef "package" is still available as before, but
  2001 users are encouraged to use the new package.
  2002 
  2003 * Method "lexicographic_order" automatically synthesizes termination
  2004 relations as lexicographic combinations of size measures. 
  2005 
  2006 * Case-expressions allow arbitrary constructor-patterns (including
  2007 "_") and take their order into account, like in functional
  2008 programming.  Internally, this is translated into nested
  2009 case-expressions; missing cases are added and mapped to the predefined
  2010 constant "undefined". In complicated cases printing may no longer show
  2011 the original input but the internal form. Lambda-abstractions allow
  2012 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2013 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2014 variable.
  2015 
  2016 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2017 is an abbreviation for "of_nat :: nat => int". The simplification
  2018 rules for "of_nat" have been changed to work like "int" did
  2019 previously.  Potential INCOMPATIBILITY:
  2020   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2021   - of_nat_diff and of_nat_mult are no longer default simp rules
  2022 
  2023 * Method "algebra" solves polynomial equations over (semi)rings using
  2024 Groebner bases. The (semi)ring structure is defined by locales and the
  2025 tool setup depends on that generic context. Installing the method for
  2026 a specific type involves instantiating the locale and possibly adding
  2027 declarations for computation on the coefficients.  The method is
  2028 already instantiated for natural numbers and for the axiomatic class
  2029 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2030 CALCULEMUS 2007 for the general principles underlying this
  2031 architecture of context-aware proof-tools.
  2032 
  2033 * Method "ferrack" implements quantifier elimination over
  2034 special-purpose dense linear orders using locales (analogous to
  2035 "algebra"). The method is already installed for class
  2036 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2037 rat, etc.
  2038 
  2039 * Former constant "List.op @" now named "List.append".  Use ML
  2040 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2041 circumvent possible incompatibilities when working on ML level.
  2042 
  2043 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2044 
  2045 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2046 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2047 
  2048 * New syntax for Haskell-like list comprehension (input only), eg.
  2049 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2050 
  2051 * The special syntax for function "filter" has changed from [x :
  2052 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2053 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2054 
  2055 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2056 defined on nat only, as an abbreviation for [a..<Suc b]
  2057 INCOMPATIBILITY.
  2058 
  2059 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2060 
  2061 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2062 
  2063 * New lemma collection field_simps (an extension of ring_simps) for
  2064 manipulating (in)equations involving division. Multiplies with all
  2065 denominators that can be proved to be non-zero (in equations) or
  2066 positive/negative (in inequations).
  2067 
  2068 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2069 have been improved and renamed to ring_simps, group_simps and
  2070 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2071 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2072 
  2073 * Theory Library/Commutative_Ring: switched from recdef to function
  2074 package; constants add, mul, pow now curried.  Infix syntax for
  2075 algebraic operations.
  2076 
  2077 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2078 INCOMPATIBILITY.
  2079 
  2080 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2081 INCOMPATIBILITY.
  2082 
  2083 * HOL/records: generalised field-update to take a function on the
  2084 field rather than the new value: r(|A := x|) is translated to A_update
  2085 (K x) r The K-combinator that is internally used is called K_record.
  2086 INCOMPATIBILITY: Usage of the plain update functions has to be
  2087 adapted.
  2088  
  2089 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2090 * x = 0, which are required for a semiring.  Richer structures do not
  2091 inherit from semiring_0 anymore, because this property is a theorem
  2092 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2093 there is more to prove, but this is mostly trivial.
  2094 
  2095 * Class "recpower" is generalized to arbitrary monoids, not just
  2096 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2097 commutativity or semiring properties additionally.
  2098 
  2099 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2100 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2101 better use 'abbreviation'.
  2102 
  2103 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2104 
  2105 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2106 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2107 significant changes for setting up numeral syntax for types:
  2108   - New constants Numeral.pred and Numeral.succ instead
  2109       of former Numeral.bin_pred and Numeral.bin_succ.
  2110   - Use integer operations instead of bin_add, bin_mult and so on.
  2111   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2112   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2113 
  2114 See src/HOL/Integ/IntArith.thy for an example setup.
  2115 
  2116 * Command 'normal_form' computes the normal form of a term that may
  2117 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2118 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2119 heavy-duty computations because the functions are compiled to ML
  2120 first.  Correspondingly, a method "normalization" is provided.  See
  2121 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2122 
  2123 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2124 25 like -->); output depends on the "iff" print_mode, the default is
  2125 "A = B" (with priority 50).
  2126 
  2127 * Relations less (<) and less_eq (<=) are also available on type bool.
  2128 Modified syntax to disallow nesting without explicit parentheses,
  2129 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2130 INCOMPATIBILITY.
  2131 
  2132 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2133 
  2134 * Relation composition operator "op O" now has precedence 75 and binds
  2135 stronger than union and intersection. INCOMPATIBILITY.
  2136 
  2137 * The old set interval syntax "{m..n(}" (and relatives) has been
  2138 removed.  Use "{m..<n}" (and relatives) instead.
  2139 
  2140 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2141 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2142 ``declare [[simproc del: neq]]''.
  2143 
  2144 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2145 True/False.
  2146 
  2147 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2148 
  2149 * Theorem setsum_mult renamed to setsum_right_distrib.
  2150 
  2151 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2152 ``rule'' method.
  2153 
  2154 * Reimplemented methods "sat" and "satx", with several improvements:
  2155 goals no longer need to be stated as "<prems> ==> False", equivalences
  2156 (i.e. "=" on type bool) are handled, variable names of the form
  2157 "lit_<n>" are no longer reserved, significant speedup.
  2158 
  2159 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2160 zChaff is still supported as well.
  2161 
  2162 * 'inductive' and 'datatype': provide projections of mutual rules,
  2163 bundled as foo_bar.inducts;
  2164 
  2165 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2166 Library.
  2167 
  2168 * Library: moved theory Accessible_Part to main HOL.
  2169 
  2170 * Library: added theory Coinductive_List of potentially infinite lists
  2171 as greatest fixed-point.
  2172 
  2173 * Library: added theory AssocList which implements (finite) maps as
  2174 association lists.
  2175 
  2176 * Method "evaluation" solves goals (i.e. a boolean expression)
  2177 efficiently by compiling it to ML.  The goal is "proved" (via an
  2178 oracle) if it evaluates to True.
  2179 
  2180 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2181 also when invoked by the simplifier.  This results in the Simplifier
  2182 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2183 Configuration option fast_arith_split_limit=0 recovers the old
  2184 behavior.
  2185 
  2186 * Support for hex (0x20) and binary (0b1001) numerals.
  2187 
  2188 * New method: reify eqs (t), where eqs are equations for an
  2189 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2190 parameter, computes a term s::'b and a list xs::'a list and proves the
  2191 theorem I xs s = t. This is also known as reification or quoting. The
  2192 resulting theorem is applied to the subgoal to substitute t with I xs
  2193 s.  If t is omitted, the subgoal itself is reified.
  2194 
  2195 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2196 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2197 where f is supposed to be a computable function (in the sense of code
  2198 generattion). The method uses reify to compute s and xs as above then
  2199 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2200 r and finally gets the theorem t = r, which is again applied to the
  2201 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2202 
  2203 * Reflection: Automatic reification now handels binding, an example is
  2204 available in src/HOL/ex/ReflectionEx.thy
  2205 
  2206 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2207 command 'statespace' that is similar to 'record', but introduces an
  2208 abstract specification based on the locale infrastructure instead of
  2209 HOL types.  This leads to extra flexibility in composing state spaces,
  2210 in particular multiple inheritance and renaming of components.
  2211 
  2212 
  2213 *** HOL-Complex ***
  2214 
  2215 * Hyperreal: Functions root and sqrt are now defined on negative real
  2216 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2217 Nonnegativity side conditions have been removed from many lemmas, so
  2218 that more subgoals may now be solved by simplification; potential
  2219 INCOMPATIBILITY.
  2220 
  2221 * Real: new type classes formalize real normed vector spaces and
  2222 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2223 and norm :: 'a => real.
  2224 
  2225 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2226 reals into other types. The overloaded constant Reals :: 'a set is now
  2227 defined as range of_real; potential INCOMPATIBILITY.
  2228 
  2229 * Real: proper support for ML code generation, including 'quickcheck'.
  2230 Reals are implemented as arbitrary precision rationals.
  2231 
  2232 * Hyperreal: Several constants that previously worked only for the
  2233 reals have been generalized, so they now work over arbitrary vector
  2234 spaces. Type annotations may need to be added in some cases; potential
  2235 INCOMPATIBILITY.
  2236 
  2237   Infinitesimal  :: ('a::real_normed_vector) star set
  2238   HFinite        :: ('a::real_normed_vector) star set
  2239   HInfinite      :: ('a::real_normed_vector) star set
  2240   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2241   monad          :: ('a::real_normed_vector) star => 'a star set
  2242   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2243   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2244   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2245   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2246   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2247   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2248   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2249   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2250   sgn            :: 'a::real_normed_vector => 'a
  2251   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2252 
  2253 * Complex: Some complex-specific constants are now abbreviations for
  2254 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2255 hnorm.  Other constants have been entirely removed in favor of the
  2256 polymorphic versions (INCOMPATIBILITY):
  2257 
  2258   approx        <-- capprox
  2259   HFinite       <-- CFinite
  2260   HInfinite     <-- CInfinite
  2261   Infinitesimal <-- CInfinitesimal
  2262   monad         <-- cmonad
  2263   galaxy        <-- cgalaxy
  2264   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2265   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2266   (ns)deriv     <-- (ns)cderiv
  2267 
  2268 
  2269 *** HOL-Algebra ***
  2270 
  2271 * Formalisation of ideals and the quotient construction over rings.
  2272 
  2273 * Order and lattice theory no longer based on records.
  2274 INCOMPATIBILITY.
  2275 
  2276 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2277 greatest_closed.  INCOMPATIBILITY.
  2278 
  2279 * Method algebra is now set up via an attribute.  For examples see
  2280 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2281 of algebraic structures.
  2282 
  2283 * Renamed theory CRing to Ring.
  2284 
  2285 
  2286 *** HOL-Nominal ***
  2287 
  2288 * Substantial, yet incomplete support for nominal datatypes (binding
  2289 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2290 src/HOL/Nominal/Examples.  Prospective users should consult
  2291 http://isabelle.in.tum.de/nominal/
  2292 
  2293 
  2294 *** ML ***
  2295 
  2296 * ML basics: just one true type int, which coincides with IntInf.int
  2297 (even on SML/NJ).
  2298 
  2299 * ML within Isar: antiquotations allow to embed statically-checked
  2300 formal entities in the source, referring to the context available at
  2301 compile-time.  For example:
  2302 
  2303 ML {* @{sort "{zero,one}"} *}
  2304 ML {* @{typ "'a => 'b"} *}
  2305 ML {* @{term "%x. x"} *}
  2306 ML {* @{prop "x == y"} *}
  2307 ML {* @{ctyp "'a => 'b"} *}
  2308 ML {* @{cterm "%x. x"} *}
  2309 ML {* @{cprop "x == y"} *}
  2310 ML {* @{thm asm_rl} *}
  2311 ML {* @{thms asm_rl} *}
  2312 ML {* @{type_name c} *}
  2313 ML {* @{type_syntax c} *}
  2314 ML {* @{const_name c} *}
  2315 ML {* @{const_syntax c} *}
  2316 ML {* @{context} *}
  2317 ML {* @{theory} *}
  2318 ML {* @{theory Pure} *}
  2319 ML {* @{theory_ref} *}
  2320 ML {* @{theory_ref Pure} *}
  2321 ML {* @{simpset} *}
  2322 ML {* @{claset} *}
  2323 ML {* @{clasimpset} *}
  2324 
  2325 The same works for sources being ``used'' within an Isar context.
  2326 
  2327 * ML in Isar: improved error reporting; extra verbosity with
  2328 ML_Context.trace enabled.
  2329 
  2330 * Pure/General/table.ML: the join operations now works via exceptions
  2331 DUP/SAME instead of type option. This is simpler in simple cases, and
  2332 admits slightly more efficient complex applications.
  2333 
  2334 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2335 use Context.generic instead of just theory.
  2336 
  2337 * Pure: datatype Context.generic joins theory/Proof.context and
  2338 provides some facilities for code that works in either kind of
  2339 context, notably GenericDataFun for uniform theory and proof data.
  2340 
  2341 * Pure: simplified internal attribute type, which is now always
  2342 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2343 local (Proof.context) attributes have been discontinued, while
  2344 minimizing code duplication. Thm.rule_attribute and
  2345 Thm.declaration_attribute build canonical attributes; see also structure
  2346 Context for further operations on Context.generic, notably
  2347 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2348 declarations and definitions.
  2349 
  2350 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2351 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2352 init only required for impure data. INCOMPATIBILITY: empty really need
  2353 to be empty (no dependencies on theory content!)
  2354 
  2355 * Pure/kernel: consts certification ignores sort constraints given in
  2356 signature declarations. (This information is not relevant to the
  2357 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2358 potential INCOMPATIBILITY.
  2359 
  2360 * Pure: axiomatic type classes are now purely definitional, with
  2361 explicit proofs of class axioms and super class relations performed
  2362 internally. See Pure/axclass.ML for the main internal interfaces --
  2363 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2364 AxClass.axiomatize_class/classrel/arity supersede
  2365 Sign.add_classes/classrel/arities.
  2366 
  2367 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2368 global/local versions on theory vs. Proof.context have been
  2369 discontinued; Attrib.syntax and Method.syntax have been adapted
  2370 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2371 attributes, methods, etc.
  2372 
  2373 * Pure: several functions of signature "... -> theory -> theory * ..."
  2374 have been reoriented to "... -> theory -> ... * theory" in order to
  2375 allow natural usage in combination with the ||>, ||>>, |-> and
  2376 fold_map combinators.
  2377 
  2378 * Pure: official theorem names (closed derivations) and additional
  2379 comments (tags) are now strictly separate.  Name hints -- which are
  2380 maintained as tags -- may be attached any time without affecting the
  2381 derivation.
  2382 
  2383 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2384 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2385 achieve the old behaviour.
  2386 
  2387 * Pure: the "Goal" constant is now called "prop", supporting a
  2388 slightly more general idea of ``protecting'' meta-level rule
  2389 statements.
  2390 
  2391 * Pure: Logic.(un)varify only works in a global context, which is now
  2392 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2393 Logic.legacy_(un)varify as temporary workaround.
  2394 
  2395 * Pure: structure Name provides scalable operations for generating
  2396 internal variable names, notably Name.variants etc.  This replaces
  2397 some popular functions from term.ML:
  2398 
  2399   Term.variant		->  Name.variant
  2400   Term.variantlist	->  Name.variant_list
  2401   Term.invent_names	->  Name.invent_list
  2402 
  2403 Note that low-level renaming rarely occurs in new code -- operations
  2404 from structure Variable are used instead (see below).
  2405 
  2406 * Pure: structure Variable provides fundamental operations for proper
  2407 treatment of fixed/schematic variables in a context.  For example,
  2408 Variable.import introduces fixes for schematics of given facts and
  2409 Variable.export reverses the effect (up to renaming) -- this replaces
  2410 various freeze_thaw operations.
  2411 
  2412 * Pure: structure Goal provides simple interfaces for
  2413 init/conclude/finish and tactical prove operations (replacing former
  2414 Tactic.prove).  Goal.prove is the canonical way to prove results
  2415 within a given context; Goal.prove_global is a degraded version for
  2416 theory level goals, including a global Drule.standard.  Note that
  2417 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2418 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2419 in a locale context).
  2420 
  2421 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2422 and type checking (Syntax.check_term etc.), with common combinations
  2423 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2424 which are considered legacy and await removal.
  2425 
  2426 * Pure/Syntax: generic interfaces for type unchecking
  2427 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2428 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2429 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2430 available for convenience, but refer to the very same operations using
  2431 a mere theory instead of a full context.
  2432 
  2433 * Isar: simplified treatment of user-level errors, using exception
  2434 ERROR of string uniformly.  Function error now merely raises ERROR,
  2435 without any side effect on output channels.  The Isar toplevel takes
  2436 care of proper display of ERROR exceptions.  ML code may use plain
  2437 handle/can/try; cat_error may be used to concatenate errors like this:
  2438 
  2439   ... handle ERROR msg => cat_error msg "..."
  2440 
  2441 Toplevel ML code (run directly or through the Isar toplevel) may be
  2442 embedded into the Isar toplevel with exception display/debug like
  2443 this:
  2444 
  2445   Isar.toplevel (fn () => ...)
  2446 
  2447 INCOMPATIBILITY, removed special transform_error facilities, removed
  2448 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2449 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2450 -- use plain ERROR instead.
  2451 
  2452 * Isar: theory setup now has type (theory -> theory), instead of a
  2453 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2454 
  2455 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2456 ProofContext.debug/verbose flags.
  2457 
  2458 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2459 theory before entering a proof state.  Transactions now always see a
  2460 quasi-functional intermediate checkpoint, both in interactive and
  2461 batch mode.
  2462 
  2463 * Isar: simplified interfaces for outer syntax.  Renamed
  2464 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2465 OuterSyntax.add_parsers -- this functionality is now included in
  2466 OuterSyntax.command etc.  INCOMPATIBILITY.
  2467 
  2468 * Simplifier: the simpset of a running simplification process now
  2469 contains a proof context (cf. Simplifier.the_context), which is the
  2470 very context that the initial simpset has been retrieved from (by
  2471 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2472 (solver, looper etc.) may depend on arbitrary proof data.
  2473 
  2474 * Simplifier.inherit_context inherits the proof context (plus the
  2475 local bounds) of the current simplification process; any simproc
  2476 etc. that calls the Simplifier recursively should do this!  Removed
  2477 former Simplifier.inherit_bounds, which is already included here --
  2478 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2479 specify an explicit context using Simplifier.context/theory_context.
  2480 
  2481 * Simplifier/Classical Reasoner: more abstract interfaces
  2482 change_simpset/claset for modifying the simpset/claset reference of a
  2483 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2484 INCOMPATIBILITY.
  2485 
  2486 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2487 "Trueprop" etc.
  2488 
  2489 
  2490 *** System ***
  2491 
  2492 * settings: the default heap location within ISABELLE_HOME_USER now
  2493 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2494 Isabelle installations.
  2495 
  2496 * isabelle-process: option -S (secure mode) disables some critical
  2497 operations, notably runtime compilation and evaluation of ML source
  2498 code.
  2499 
  2500 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2501 
  2502 * Support for parallel execution, using native multicore support of
  2503 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2504 independent theories, according to the given theory header
  2505 specifications. The maximum number of worker threads is specified via
  2506 usedir option -M or the "max-threads" setting in Proof General. A
  2507 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2508 to 6 on a 8-core machine.  User-code needs to observe certain
  2509 guidelines for thread-safe programming, see appendix A in the Isar
  2510 Implementation manual.
  2511 
  2512 
  2513 
  2514 New in Isabelle2005 (October 2005)
  2515 ----------------------------------
  2516 
  2517 *** General ***
  2518 
  2519 * Theory headers: the new header syntax for Isar theories is
  2520 
  2521   theory <name>
  2522   imports <theory1> ... <theoryN>
  2523   uses <file1> ... <fileM>
  2524   begin
  2525 
  2526 where the 'uses' part is optional.  The previous syntax
  2527 
  2528   theory <name> = <theory1> + ... + <theoryN>:
  2529 
  2530 will disappear in the next release.  Use isatool fixheaders to convert
  2531 existing theory files.  Note that there is no change in ancient
  2532 non-Isar theories now, but these will disappear soon.
  2533 
  2534 * Theory loader: parent theories can now also be referred to via
  2535 relative and absolute paths.
  2536 
  2537 * Command 'find_theorems' searches for a list of criteria instead of a
  2538 list of constants. Known criteria are: intro, elim, dest, name:string,
  2539 simp:term, and any term. Criteria can be preceded by '-' to select
  2540 theorems that do not match. Intro, elim, dest select theorems that
  2541 match the current goal, name:s selects theorems whose fully qualified
  2542 name contain s, and simp:term selects all simplification rules whose
  2543 lhs match term.  Any other term is interpreted as pattern and selects
  2544 all theorems matching the pattern. Available in ProofGeneral under
  2545 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2546 
  2547   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2548 
  2549 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2550 matching the current goal as introduction rule and not having "HOL."
  2551 in their name (i.e. not being defined in theory HOL).
  2552 
  2553 * Command 'thms_containing' has been discontinued in favour of
  2554 'find_theorems'; INCOMPATIBILITY.
  2555 
  2556 * Communication with Proof General is now 8bit clean, which means that
  2557 Unicode text in UTF-8 encoding may be used within theory texts (both
  2558 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2559 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2560 
  2561   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2562   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2563 
  2564 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2565 Classical Reasoner.  Typical big applications run around 2 times
  2566 faster.
  2567 
  2568 
  2569 *** Document preparation ***
  2570 
  2571 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2572 of raw sources.  Only those symbols that do not require additional
  2573 LaTeX packages (depending on comments in isabellesym.sty) are
  2574 displayed properly, everything else is left verbatim.  isatool display
  2575 and isatool print are used as front ends (these are subject to the
  2576 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2577 
  2578 * Command tags control specific markup of certain regions of text,
  2579 notably folding and hiding.  Predefined tags include "theory" (for
  2580 theory begin and end), "proof" for proof commands, and "ML" for
  2581 commands involving ML code; the additional tags "visible" and
  2582 "invisible" are unused by default.  Users may give explicit tag
  2583 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2584 interpretation of tags is determined by the LaTeX job during document
  2585 preparation: see option -V of isatool usedir, or options -n and -t of
  2586 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2587 \isadroptag.
  2588 
  2589 Several document versions may be produced at the same time via isatool
  2590 usedir (the generated index.html will link all of them).  Typical
  2591 specifications include ''-V document=theory,proof,ML'' to present
  2592 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2593 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2594 these parts without any formal replacement text.  The Isabelle site
  2595 default settings produce ''document'' and ''outline'' versions as
  2596 specified above.
  2597 
  2598 * Several new antiquotations:
  2599 
  2600   @{term_type term} prints a term with its type annotated;
  2601 
  2602   @{typeof term} prints the type of a term;
  2603 
  2604   @{const const} is the same as @{term const}, but checks that the
  2605   argument is a known logical constant;
  2606 
  2607   @{term_style style term} and @{thm_style style thm} print a term or
  2608   theorem applying a "style" to it
  2609 
  2610   @{ML text}
  2611 
  2612 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2613 definitions, equations, inequations etc., 'concl' printing only the
  2614 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2615 to print the specified premise.  TermStyle.add_style provides an ML
  2616 interface for introducing further styles.  See also the "LaTeX Sugar"
  2617 document practical applications.  The ML antiquotation prints
  2618 type-checked ML expressions verbatim.
  2619 
  2620 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2621 and 'text' support optional locale specification '(in loc)', which
  2622 specifies the default context for interpreting antiquotations.  For
  2623 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2624 
  2625 * Option 'locale=NAME' of antiquotations specifies an alternative
  2626 context interpreting the subsequent argument.  For example: @{thm
  2627 [locale=lattice] inf_assoc}.
  2628 
  2629 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2630 a proof context.
  2631 
  2632 * Proper output of antiquotations for theory commands involving a
  2633 proof context (such as 'locale' or 'theorem (in loc) ...').
  2634 
  2635 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2636 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2637 
  2638 * isatool usedir: new option -C (default true) controls whether option
  2639 -D should include a copy of the original document directory; -C false
  2640 prevents unwanted effects such as copying of administrative CVS data.
  2641 
  2642 
  2643 *** Pure ***
  2644 
  2645 * Considerably improved version of 'constdefs' command.  Now performs
  2646 automatic type-inference of declared constants; additional support for
  2647 local structure declarations (cf. locales and HOL records), see also
  2648 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2649 sequential dependencies of definitions within a single 'constdefs'
  2650 section; moreover, the declared name needs to be an identifier.  If
  2651 all fails, consider to fall back on 'consts' and 'defs' separately.
  2652 
  2653 * Improved indexed syntax and implicit structures.  First of all,
  2654 indexed syntax provides a notational device for subscripted
  2655 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2656 expressions.  Secondly, in a local context with structure
  2657 declarations, number indexes \<^sub>n or the empty index (default
  2658 number 1) refer to a certain fixed variable implicitly; option
  2659 show_structs controls printing of implicit structures.  Typical
  2660 applications of these concepts involve record types and locales.
  2661 
  2662 * New command 'no_syntax' removes grammar declarations (and
  2663 translations) resulting from the given syntax specification, which is
  2664 interpreted in the same manner as for the 'syntax' command.
  2665 
  2666 * 'Advanced' translation functions (parse_translation etc.) may depend
  2667 on the signature of the theory context being presently used for
  2668 parsing/printing, see also isar-ref manual.
  2669 
  2670 * Improved 'oracle' command provides a type-safe interface to turn an
  2671 ML expression of type theory -> T -> term into a primitive rule of
  2672 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2673 is already included here); see also FOL/ex/IffExample.thy;
  2674 INCOMPATIBILITY.
  2675 
  2676 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2677 before); "cI" is no longer bound, use "c.intro" instead.
  2678 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2679 axclasses vs. locales.
  2680 
  2681 * Improved internal renaming of symbolic identifiers -- attach primes
  2682 instead of base 26 numbers.
  2683 
  2684 * New flag show_question_marks controls printing of leading question
  2685 marks in schematic variable names.
  2686 
  2687 * In schematic variable names, *any* symbol following \<^isub> or
  2688 \<^isup> is now treated as part of the base name.  For example, the
  2689 following works without printing of awkward ".0" indexes:
  2690 
  2691   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2692     by simp
  2693 
  2694 * Inner syntax includes (*(*nested*) comments*).
  2695 
  2696 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2697 annotations as "(00...)".
  2698 
  2699 * Clear separation of logical types and nonterminals, where the latter
  2700 may only occur in 'syntax' specifications or type abbreviations.
  2701 Before that distinction was only partially implemented via type class
  2702 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2703 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2704 exotic syntax specifications may require further adaption
  2705 (e.g. Cube/Cube.thy).
  2706 
  2707 * Removed obsolete type class "logic", use the top sort {} instead.
  2708 Note that non-logical types should be declared as 'nonterminals'
  2709 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2710 specifications.
  2711 
  2712 * Attributes 'induct' and 'cases': type or set names may now be
  2713 locally fixed variables as well.
  2714 
  2715 * Simplifier: can now control the depth to which conditional rewriting
  2716 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2717 Limit.
  2718 
  2719 * Simplifier: simplification procedures may now take the current
  2720 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2721 interface), which is very useful for calling the Simplifier
  2722 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2723 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2724 low-level mk_simproc no longer applies Logic.varify internally, to
  2725 allow for use in a context of fixed variables.
  2726 
  2727 * thin_tac now works even if the assumption being deleted contains !!
  2728 or ==>.  More generally, erule now works even if the major premise of
  2729 the elimination rule contains !! or ==>.
  2730 
  2731 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2732 
  2733 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2734 from Pure, which contains all common declarations already.  Both
  2735 theories are defined via plain Isabelle/Isar .thy files.
  2736 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2737 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2738 use isatool fixcpure to adapt your theory and ML sources.
  2739 
  2740 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2741 selections of theorems in named facts via index ranges.
  2742 
  2743 * 'print_theorems': in theory mode, really print the difference
  2744 wrt. the last state (works for interactive theory development only),
  2745 in proof mode print all local facts (cf. 'print_facts');
  2746 
  2747 * 'hide': option '(open)' hides only base names.
  2748 
  2749 * More efficient treatment of intermediate checkpoints in interactive
  2750 theory development.
  2751 
  2752 * Code generator is now invoked via code_module (incremental code
  2753 generation) and code_library (modular code generation, ML structures
  2754 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2755 must be quoted when used as identifiers.
  2756 
  2757 * New 'value' command for reading, evaluating and printing terms using
  2758 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2759 quoted when used as identifier.
  2760 
  2761 
  2762 *** Locales ***
  2763 
  2764 * New commands for the interpretation of locale expressions in
  2765 theories (1), locales (2) and proof contexts (3).  These generate
  2766 proof obligations from the expression specification.  After the
  2767 obligations have been discharged, theorems of the expression are added
  2768 to the theory, target locale or proof context.  The synopsis of the
  2769 commands is a follows:
  2770 
  2771   (1) interpretation expr inst
  2772   (2) interpretation target < expr
  2773   (3) interpret expr inst
  2774 
  2775 Interpretation in theories and proof contexts require a parameter
  2776 instantiation of terms from the current context.  This is applied to
  2777 specifications and theorems of the interpreted expression.
  2778 Interpretation in locales only permits parameter renaming through the
  2779 locale expression.  Interpretation is smart in that interpretations
  2780 that are active already do not occur in proof obligations, neither are
  2781 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2782 inspect active interpretations of a particular locale.  For details,
  2783 see the Isar Reference manual.  Examples can be found in
  2784 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2785 
  2786 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2787 'interpret' instead.
  2788 
  2789 * New context element 'constrains' for adding type constraints to
  2790 parameters.
  2791 
  2792 * Context expressions: renaming of parameters with syntax
  2793 redeclaration.
  2794 
  2795 * Locale declaration: 'includes' disallowed.
  2796 
  2797 * Proper static binding of attribute syntax -- i.e. types / terms /
  2798 facts mentioned as arguments are always those of the locale definition
  2799 context, independently of the context of later invocations.  Moreover,
  2800 locale operations (renaming and type / term instantiation) are applied
  2801 to attribute arguments as expected.
  2802 
  2803 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2804 actual attributes; rare situations may require Attrib.attribute to
  2805 embed those attributes into Attrib.src that lack concrete syntax.
  2806 Attribute implementations need to cooperate properly with the static
  2807 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2808 Attrib.XXX_thm etc. already do the right thing without further
  2809 intervention.  Only unusual applications -- such as "where" or "of"
  2810 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2811 on the context and the facts involved -- may have to assign parsed
  2812 values to argument tokens explicitly.
  2813 
  2814 * Changed parameter management in theorem generation for long goal
  2815 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2816 theorem statement in rare situations.
  2817 
  2818 * Locale inspection command 'print_locale' omits notes elements.  Use
  2819 'print_locale!' to have them included in the output.
  2820 
  2821 
  2822 *** Provers ***
  2823 
  2824 * Provers/hypsubst.ML: improved version of the subst method, for
  2825 single-step rewriting: it now works in bound variable contexts. New is
  2826 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2827 rewrite a different subterm than the original subst method, which is
  2828 still available as 'simplesubst'.
  2829 
  2830 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2831 and quasi orders.
  2832 
  2833 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2834 reflexive-transitive closure of relations.
  2835 
  2836 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2837 limit (previously hard-coded with a value of 20) user-definable.
  2838 
  2839 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2840 is peformed already.  Object-logics merely need to finish their
  2841 initial simpset configuration as before.  INCOMPATIBILITY.
  2842 
  2843 
  2844 *** HOL ***
  2845 
  2846 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2847 
  2848   syntax (epsilon)
  2849     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2850 
  2851 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2852 and x-symbol; use option '-m epsilon' to get it actually printed.
  2853 Moreover, the mathematically important symbolic identifier \<epsilon>
  2854 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2855 
  2856 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2857 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2858 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2859 support corresponding Isar calculations.
  2860 
  2861 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2862 instead of ":".
  2863 
  2864 * theory SetInterval: changed the syntax for open intervals:
  2865 
  2866   Old       New
  2867   {..n(}    {..<n}
  2868   {)n..}    {n<..}
  2869   {m..n(}   {m..<n}
  2870   {)m..n}   {m<..n}
  2871   {)m..n(}  {m<..<n}
  2872 
  2873 The old syntax is still supported but will disappear in the next
  2874 release.  For conversion use the following Emacs search and replace
  2875 patterns (these are not perfect but work quite well):
  2876 
  2877   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2878   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2879 
  2880 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2881 equalities in commutative rings; method 'algebra' provides a generic
  2882 interface.
  2883 
  2884 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2885 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2886 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2887 be a tuple pattern.
  2888 
  2889 Some new syntax forms are available:
  2890 
  2891   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2892   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2893   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2894   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2895 
  2896 The latter form "\<Sum>x < k. e" used to be based on a separate
  2897 function "Summation", which has been discontinued.
  2898 
  2899 * theory Finite_Set: in structured induction proofs, the insert case
  2900 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2901 (insert F x)'.
  2902 
  2903 * The 'refute' command has been extended to support a much larger
  2904 fragment of HOL, including axiomatic type classes, constdefs and
  2905 typedefs, inductive datatypes and recursion.
  2906 
  2907 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2908 Requires zChaff with proof generation to be installed.  See
  2909 HOL/ex/SAT_Examples.thy for examples.
  2910 
  2911 * Datatype induction via method 'induct' now preserves the name of the
  2912 induction variable. For example, when proving P(xs::'a list) by
  2913 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2914 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2915 in unstructured proof scripts.
  2916 
  2917 * Reworked implementation of records.  Improved scalability for
  2918 records with many fields, avoiding performance problems for type
  2919 inference. Records are no longer composed of nested field types, but
  2920 of nested extension types. Therefore the record type only grows linear
  2921 in the number of extensions and not in the number of fields.  The
  2922 top-level (users) view on records is preserved.  Potential
  2923 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2924 old record representation. The type generated for a record is called
  2925 <record_name>_ext_type.
  2926 
  2927 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2928 proofs triggered by a record definition or a simproc (if
  2929 quick_and_dirty is enabled).  Definitions of large records can take
  2930 quite long.
  2931 
  2932 New simproc record_upd_simproc for simplification of multiple record
  2933 updates enabled by default.  Moreover, trivial updates are also
  2934 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2935 occasionally, since simplification is more powerful by default.
  2936 
  2937 * typedef: proper support for polymorphic sets, which contain extra
  2938 type-variables in the term.
  2939 
  2940 * Simplifier: automatically reasons about transitivity chains
  2941 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2942 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2943 old proofs break occasionally as simplification may now solve more
  2944 goals than previously.
  2945 
  2946 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2947 present.  Works for all partial orders (class "order"), in particular
  2948 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2949 just like y <= x.
  2950 
  2951 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2952 bound variable or a constant then the let is unfolded.  Otherwise
  2953 first a is simplified to b, and then f b is simplified to g. If
  2954 possible we abstract b from g arriving at "let x = b in h x",
  2955 otherwise we unfold the let and arrive at g.  The simproc can be
  2956 enabled/disabled by the reference use_let_simproc.  Potential
  2957 INCOMPATIBILITY since simplification is more powerful by default.
  2958 
  2959 * Classical reasoning: the meson method now accepts theorems as arguments.
  2960 
  2961 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2962 jobs to provide advice on the provability of subgoals.
  2963 
  2964 * Theory OrderedGroup and Ring_and_Field: various additions and
  2965 improvements to faciliate calculations involving equalities and
  2966 inequalities.
  2967 
  2968 The following theorems have been eliminated or modified
  2969 (INCOMPATIBILITY):
  2970 
  2971   abs_eq             now named abs_of_nonneg
  2972   abs_of_ge_0        now named abs_of_nonneg
  2973   abs_minus_eq       now named abs_of_nonpos
  2974   imp_abs_id         now named abs_of_nonneg
  2975   imp_abs_neg_id     now named abs_of_nonpos
  2976   mult_pos           now named mult_pos_pos
  2977   mult_pos_le        now named mult_nonneg_nonneg
  2978   mult_pos_neg_le    now named mult_nonneg_nonpos
  2979   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2980   mult_neg           now named mult_neg_neg
  2981   mult_neg_le        now named mult_nonpos_nonpos
  2982 
  2983 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2984      
  2985      zero_le_square
  2986      not_square_less_zero 
  2987 
  2988   The following lemmas have been deleted from Real/RealPow:
  2989   
  2990      realpow_zero_zero
  2991      realpow_two
  2992      realpow_less
  2993      zero_le_power
  2994      realpow_two_le
  2995      abs_realpow_two
  2996      realpow_two_abs     
  2997 
  2998 * Theory Parity: added rules for simplifying exponents.
  2999 
  3000 * Theory List:
  3001 
  3002 The following theorems have been eliminated or modified
  3003 (INCOMPATIBILITY):
  3004 
  3005   list_all_Nil       now named list_all.simps(1)
  3006   list_all_Cons      now named list_all.simps(2)
  3007   list_all_conv      now named list_all_iff
  3008   set_mem_eq         now named mem_iff
  3009 
  3010 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3011 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3012 
  3013 
  3014 *** HOL-Complex ***
  3015 
  3016 * Theory RealDef: better support for embedding natural numbers and
  3017 integers in the reals.
  3018 
  3019 The following theorems have been eliminated or modified
  3020 (INCOMPATIBILITY):
  3021 
  3022   exp_ge_add_one_self  now requires no hypotheses
  3023   real_of_int_add      reversed direction of equality (use [symmetric])
  3024   real_of_int_minus    reversed direction of equality (use [symmetric])
  3025   real_of_int_diff     reversed direction of equality (use [symmetric])
  3026   real_of_int_mult     reversed direction of equality (use [symmetric])
  3027 
  3028 * Theory RComplete: expanded support for floor and ceiling functions.
  3029 
  3030 * Theory Ln is new, with properties of the natural logarithm
  3031 
  3032 * Hyperreal: There is a new type constructor "star" for making
  3033 nonstandard types.  The old type names are now type synonyms:
  3034 
  3035   hypreal = real star
  3036   hypnat = nat star
  3037   hcomplex = complex star
  3038 
  3039 * Hyperreal: Many groups of similarly-defined constants have been
  3040 replaced by polymorphic versions (INCOMPATIBILITY):
  3041 
  3042   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3043 
  3044   starset      <-- starsetNat, starsetC
  3045   *s*          <-- *sNat*, *sc*
  3046   starset_n    <-- starsetNat_n, starsetC_n
  3047   *sn*         <-- *sNatn*, *scn*
  3048   InternalSets <-- InternalNatSets, InternalCSets
  3049 
  3050   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3051   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3052   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3053   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3054   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3055 
  3056 * Hyperreal: Many type-specific theorems have been removed in favor of
  3057 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3058 
  3059   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3060   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3061   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3062   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3063   right_minus <-- hypreal_add_minus
  3064   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3065   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3066   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3067   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3068   mult_1_right <-- hcomplex_mult_one_right
  3069   mult_zero_left <-- hcomplex_mult_zero_left
  3070   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3071   right_distrib <-- hypnat_add_mult_distrib2
  3072   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3073   right_inverse <-- hypreal_mult_inverse
  3074   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3075   order_refl <-- {hypreal,hypnat}_le_refl
  3076   order_trans <-- {hypreal,hypnat}_le_trans
  3077   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3078   order_less_le <-- {hypreal,hypnat}_less_le
  3079   linorder_linear <-- {hypreal,hypnat}_le_linear
  3080   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3081   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3082   add_nonneg_nonneg <-- hypreal_le_add_order
  3083 
  3084 * Hyperreal: Separate theorems having to do with type-specific
  3085 versions of constants have been merged into theorems that apply to the
  3086 new polymorphic constants (INCOMPATIBILITY):
  3087 
  3088   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3089   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3090   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3091   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3092   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3093   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3094   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3095   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3096   STAR_diff <-- {STAR,STARC}_diff
  3097   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3098     STARC_hcomplex_of_complex}_image_subset
  3099   starset_n_Un <-- starset{Nat,C}_n_Un
  3100   starset_n_Int <-- starset{Nat,C}_n_Int
  3101   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3102   starset_n_diff <-- starset{Nat,C}_n_diff
  3103   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3104   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3105   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3106   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3107   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3108   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3109   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3110   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3111   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3112   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3113   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3114   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3115   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3116   starfun_diff <-- starfun{C,RC,CR}_diff
  3117   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3118   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3119   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3120   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3121   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3122   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3123   starfun_Id <-- starfunC_Id
  3124   starfun_approx <-- starfun{Nat,CR}_approx
  3125   starfun_capprox <-- starfun{C,RC}_capprox
  3126   starfun_abs <-- starfunNat_rabs
  3127   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3128   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3129   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3130   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3131   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3132   starfun_add_approx <-- starfunCR_add_approx
  3133   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3134   starfun_divide <-- starfun{C,CR,RC}_divide
  3135   starfun_n <-- starfun{Nat,C}_n
  3136   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3137   starfun_n_add <-- starfun{Nat,C}_n_add
  3138   starfun_n_add_minus <-- starfunNat_n_add_minus
  3139   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3140   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3141   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3142 
  3143   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3144   star_n_minus <-- {hypreal,hcomplex}_minus
  3145   star_n_diff <-- {hypreal,hcomplex}_diff
  3146   star_n_mult <-- {hypreal,hcomplex}_mult
  3147   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3148   star_n_le <-- {hypreal,hypnat}_le
  3149   star_n_less <-- {hypreal,hypnat}_less
  3150   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3151   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3152   star_n_abs <-- hypreal_hrabs
  3153   star_n_divide <-- hcomplex_divide
  3154 
  3155   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3156   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3157   star_of_diff <-- hypreal_of_real_diff
  3158   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3159   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3160   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3161   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3162   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3163   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3164   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3165   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3166   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3167   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3168   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3169   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3170   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3171   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3172   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3173   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3174   star_of_power <-- hypreal_of_real_power
  3175   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3176 
  3177 * Hyperreal: new method "transfer" that implements the transfer
  3178 principle of nonstandard analysis. With a subgoal that mentions
  3179 nonstandard types like "'a star", the command "apply transfer"
  3180 replaces it with an equivalent one that mentions only standard types.
  3181 To be successful, all free variables must have standard types; non-
  3182 standard variables must have explicit universal quantifiers.
  3183 
  3184 * Hyperreal: A theory of Taylor series.
  3185 
  3186 
  3187 *** HOLCF ***
  3188 
  3189 * Discontinued special version of 'constdefs' (which used to support
  3190 continuous functions) in favor of the general Pure one with full
  3191 type-inference.
  3192 
  3193 * New simplification procedure for solving continuity conditions; it
  3194 is much faster on terms with many nested lambda abstractions (cubic
  3195 instead of exponential time).
  3196 
  3197 * New syntax for domain package: selector names are now optional.
  3198 Parentheses should be omitted unless argument is lazy, for example:
  3199 
  3200   domain 'a stream = cons "'a" (lazy "'a stream")
  3201 
  3202 * New command 'fixrec' for defining recursive functions with pattern
  3203 matching; defining multiple functions with mutual recursion is also
  3204 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3205 sinr, or any data constructor defined by the domain package. The given
  3206 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3207 syntax and examples.
  3208 
  3209 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3210 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3211 but the proof obligation additionally includes an admissibility
  3212 requirement. The packages generate instances of class cpo or pcpo,
  3213 with continuity and strictness theorems for Rep and Abs.
  3214 
  3215 * HOLCF: Many theorems have been renamed according to a more standard naming
  3216 scheme (INCOMPATIBILITY):
  3217 
  3218   foo_inject:  "foo$x = foo$y ==> x = y"
  3219   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3220   foo_less:    "(foo$x << foo$y) = (x << y)"
  3221   foo_strict:  "foo$UU = UU"
  3222   foo_defined: "... ==> foo$x ~= UU"
  3223   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3224 
  3225 
  3226 *** ZF ***
  3227 
  3228 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3229 including the First Isomorphism Theorem (on quotienting by the kernel
  3230 of a homomorphism).
  3231 
  3232 * ZF/Simplifier: install second copy of type solver that actually
  3233 makes use of TC rules declared to Isar proof contexts (or locales);
  3234 the old version is still required for ML proof scripts.
  3235 
  3236 
  3237 *** Cube ***
  3238 
  3239 * Converted to Isar theory format; use locales instead of axiomatic
  3240 theories.
  3241 
  3242 
  3243 *** ML ***
  3244 
  3245 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3246 for ||>, ||>>, |>>,
  3247 
  3248 * Pure/library.ML no longer defines its own option datatype, but uses
  3249 that of the SML basis, which has constructors NONE and SOME instead of
  3250 None and Some, as well as exception Option.Option instead of OPTION.
  3251 The functions the, if_none, is_some, is_none have been adapted
  3252 accordingly, while Option.map replaces apsome.
  3253 
  3254 * Pure/library.ML: the exception LIST has been given up in favour of
  3255 the standard exceptions Empty and Subscript, as well as
  3256 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3257 superceded by the standard hd and tl functions etc.
  3258 
  3259 A number of basic list functions are no longer exported to the ML
  3260 toplevel, as they are variants of predefined functions.  The following
  3261 suggests how one can translate existing code:
  3262 
  3263     rev_append xs ys = List.revAppend (xs, ys)
  3264     nth_elem (i, xs) = List.nth (xs, i)
  3265     last_elem xs = List.last xs
  3266     flat xss = List.concat xss
  3267     seq fs = List.app fs
  3268     partition P xs = List.partition P xs
  3269     mapfilter f xs = List.mapPartial f xs
  3270 
  3271 * Pure/library.ML: several combinators for linear functional
  3272 transformations, notably reverse application and composition:
  3273 
  3274   x |> f                f #> g
  3275   (x, y) |-> f          f #-> g
  3276 
  3277 * Pure/library.ML: introduced/changed precedence of infix operators:
  3278 
  3279   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3280   infix 2 ?;
  3281   infix 3 o oo ooo oooo;
  3282   infix 4 ~~ upto downto;
  3283 
  3284 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3285 infix operators.
  3286 
  3287 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3288 fold_map support linear functional transformations and nesting.  For
  3289 example:
  3290 
  3291   fold f [x1, ..., xN] y =
  3292     y |> f x1 |> ... |> f xN
  3293 
  3294   (fold o fold) f [xs1, ..., xsN] y =
  3295     y |> fold f xs1 |> ... |> fold f xsN
  3296 
  3297   fold f [x1, ..., xN] =
  3298     f x1 #> ... #> f xN
  3299 
  3300   (fold o fold) f [xs1, ..., xsN] =
  3301     fold f xs1 #> ... #> fold f xsN
  3302 
  3303 * Pure/library.ML: the following selectors on type 'a option are
  3304 available:
  3305 
  3306   the:               'a option -> 'a  (*partial*)
  3307   these:             'a option -> 'a  where 'a = 'b list
  3308   the_default: 'a -> 'a option -> 'a
  3309   the_list:          'a option -> 'a list
  3310 
  3311 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3312 basic operations for association lists, following natural argument
  3313 order; moreover the explicit equality predicate passed here avoids
  3314 potentially expensive polymorphic runtime equality checks.
  3315 The old functions may be expressed as follows:
  3316 
  3317   assoc = uncurry (AList.lookup (op =))
  3318   assocs = these oo AList.lookup (op =)
  3319   overwrite = uncurry (AList.update (op =)) o swap
  3320 
  3321 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3322 
  3323   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3324   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3325 
  3326 replacing make_keylist and keyfilter (occassionally used)
  3327 Naive rewrites:
  3328 
  3329   make_keylist = AList.make
  3330   keyfilter = AList.find (op =)
  3331 
  3332 * eq_fst and eq_snd now take explicit equality parameter, thus
  3333   avoiding eqtypes. Naive rewrites:
  3334 
  3335     eq_fst = eq_fst (op =)
  3336     eq_snd = eq_snd (op =)
  3337 
  3338 * Removed deprecated apl and apr (rarely used).
  3339   Naive rewrites:
  3340 
  3341     apl (n, op) =>>= curry op n
  3342     apr (op, m) =>>= fn n => op (n, m)
  3343 
  3344 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3345 provides a reasonably efficient light-weight implementation of sets as
  3346 lists.
  3347 
  3348 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3349 few new operations; existing lookup and update are now curried to
  3350 follow natural argument order (for use with fold etc.);
  3351 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3352 
  3353 * Pure/General: output via the Isabelle channels of
  3354 writeln/warning/error etc. is now passed through Output.output, with a
  3355 hook for arbitrary transformations depending on the print_mode
  3356 (cf. Output.add_mode -- the first active mode that provides a output
  3357 function wins).  Already formatted output may be embedded into further
  3358 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3359 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3360 accommodate easy composition of diagnostic messages etc.  Programmers
  3361 rarely need to care about Output.output or Output.raw at all, with
  3362 some notable exceptions: Output.output is required when bypassing the
  3363 standard channels (writeln etc.), or in token translations to produce
  3364 properly formatted results; Output.raw is required when capturing
  3365 already output material that will eventually be presented to the user
  3366 a second time.  For the default print mode, both Output.output and
  3367 Output.raw have no effect.
  3368 
  3369 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3370 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3371 cumulative results are displayed at the end of a batch session.
  3372 
  3373 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3374 replaced by File.platform_path and File.shell_path (with appropriate
  3375 hooks).  This provides a clean interface for unusual systems where the
  3376 internal and external process view of file names are different.
  3377 
  3378 * Pure: more efficient orders for basic syntactic entities: added
  3379 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3380 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3381 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3382 orders now -- potential INCOMPATIBILITY for code that depends on a
  3383 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3384 Library.sort_strings on result).
  3385 
  3386 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3387 fold_types traverse types/terms from left to right, observing natural
  3388 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3389 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3390 
  3391 * Pure: name spaces have been refined, with significant changes of the
  3392 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3393 to extern(_table).  The plain name entry path is superceded by a
  3394 general 'naming' context, which also includes the 'policy' to produce
  3395 a fully qualified name and external accesses of a fully qualified
  3396 name; NameSpace.extend is superceded by context dependent
  3397 Sign.declare_name.  Several theory and proof context operations modify
  3398 the naming context.  Especially note Theory.restore_naming and
  3399 ProofContext.restore_naming to get back to a sane state; note that
  3400 Theory.add_path is no longer sufficient to recover from
  3401 Theory.absolute_path in particular.
  3402 
  3403 * Pure: new flags short_names (default false) and unique_names
  3404 (default true) for controlling output of qualified names.  If
  3405 short_names is set, names are printed unqualified.  If unique_names is
  3406 reset, the name prefix is reduced to the minimum required to achieve
  3407 the original result when interning again, even if there is an overlap
  3408 with earlier declarations.
  3409 
  3410 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3411 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3412 (useful for printing error messages).  INCOMPATIBILITY.
  3413 
  3414 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3415 Theory.theory are now identified, referring to the universal
  3416 Context.theory (see Pure/context.ML).  Actual signature and theory
  3417 content is managed as theory data.  The old code and interfaces were
  3418 spread over many files and structures; the new arrangement introduces
  3419 considerable INCOMPATIBILITY to gain more clarity:
  3420 
  3421   Context -- theory management operations (name, identity, inclusion,
  3422     parents, ancestors, merge, etc.), plus generic theory data;
  3423 
  3424   Sign -- logical signature and syntax operations (declaring consts,
  3425     types, etc.), plus certify/read for common entities;
  3426 
  3427   Theory -- logical theory operations (stating axioms, definitions,
  3428     oracles), plus a copy of logical signature operations (consts,
  3429     types, etc.); also a few basic management operations (Theory.copy,
  3430     Theory.merge, etc.)
  3431 
  3432 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3433 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3434 for convenience -- they merely return the theory.
  3435 
  3436 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3437 
  3438 * Pure: the Isar proof context type is already defined early in Pure
  3439 as Context.proof (note that ProofContext.context and Proof.context are
  3440 aliases, where the latter is the preferred name).  This enables other
  3441 Isabelle components to refer to that type even before Isar is present.
  3442 
  3443 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3444 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3445 any of these kinds.  For example, Sign.intern typeK is now
  3446 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3447 Theory.hide_types.  Also note that former
  3448 Theory.hide_classes/types/consts are now
  3449 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3450 internalize their arguments!  INCOMPATIBILITY.
  3451 
  3452 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3453 datatype thmref (with constructors Name and NameSelection) instead of
  3454 plain string -- INCOMPATIBILITY;
  3455 
  3456 * Pure: cases produced by proof methods specify options, where NONE
  3457 means to remove case bindings -- INCOMPATIBILITY in
  3458 (RAW_)METHOD_CASES.
  3459 
  3460 * Pure: the following operations retrieve axioms or theorems from a
  3461 theory node or theory hierarchy, respectively:
  3462 
  3463   Theory.axioms_of: theory -> (string * term) list
  3464   Theory.all_axioms_of: theory -> (string * term) list
  3465   PureThy.thms_of: theory -> (string * thm) list
  3466   PureThy.all_thms_of: theory -> (string * thm) list
  3467 
  3468 * Pure: print_tac now outputs the goal through the trace channel.
  3469 
  3470 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3471 Reference Toplevel.debug (default false) controls detailed printing
  3472 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3473 controls execution profiling -- set to 1 for time and 2 for space
  3474 (both increase the runtime).
  3475 
  3476 * Isar session: The initial use of ROOT.ML is now always timed,
  3477 i.e. the log will show the actual process times, in contrast to the
  3478 elapsed wall-clock time that the outer shell wrapper produces.
  3479 
  3480 * Simplifier: improved handling of bound variables (nameless
  3481 representation, avoid allocating new strings).  Simprocs that invoke
  3482 the Simplifier recursively should use Simplifier.inherit_bounds to
  3483 avoid local name clashes.  Failure to do so produces warnings
  3484 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3485 for further details.
  3486 
  3487 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3488 bindings for all theorems stored within a given theory; this may help
  3489 in porting non-Isar theories to Isar ones, while keeping ML proof
  3490 scripts for the time being.
  3491 
  3492 * ML operator HTML.with_charset specifies the charset begin used for
  3493 generated HTML files.  For example:
  3494 
  3495   HTML.with_charset "utf-8" use_thy "Hebrew";
  3496   HTML.with_charset "utf-8" use_thy "Chinese";
  3497 
  3498 
  3499 *** System ***
  3500 
  3501 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3502 isabelle, isatool etc.).
  3503 
  3504 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3505 isatool doc, isatool mkdir, display_drafts etc.).
  3506 
  3507 * isatool usedir: option -f allows specification of the ML file to be
  3508 used by Isabelle; default is ROOT.ML.
  3509 
  3510 * New isatool version outputs the version identifier of the Isabelle
  3511 distribution being used.
  3512 
  3513 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3514 (containing Boolean satisfiability problems) into Isabelle/HOL
  3515 theories.
  3516 
  3517 
  3518 
  3519 New in Isabelle2004 (April 2004)
  3520 --------------------------------
  3521 
  3522 *** General ***
  3523 
  3524 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3525   Replaces linorder.ML.
  3526 
  3527 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3528   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3529   (\<a>...\<z>), are now considered normal letters, and can therefore
  3530   be used anywhere where an ASCII letter (a...zA...Z) has until
  3531   now. COMPATIBILITY: This obviously changes the parsing of some
  3532   terms, especially where a symbol has been used as a binder, say
  3533   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3534   as an identifier.  Fix it by inserting a space around former
  3535   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3536   existing theory and ML files.
  3537 
  3538 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3539 
  3540 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3541   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3542   a normal (but invisible) letter. For multiple letter subscripts repeat
  3543   \<^isub> like this: x\<^isub>1\<^isub>2.
  3544 
  3545 * Pure: There are now sub-/superscripts that can span more than one
  3546   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3547   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3548   superscript. The new control characters are not identifier parts.
  3549 
  3550 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3551   content of "..." to the latex file instead of \isacntrl... . The "..."
  3552   may consist of any printable characters excluding the end bracket >.
  3553 
  3554 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3555   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3556   declare constants "final", which prevents their being given a definition
  3557   later.  It is useful for constants whose behaviour is fixed axiomatically
  3558   rather than definitionally, such as the meta-logic connectives.
  3559 
  3560 * Pure: 'instance' now handles general arities with general sorts
  3561   (i.e. intersections of classes),
  3562 
  3563 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3564   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3565   It can be changed to alter the colors/layout of generated pages.
  3566 
  3567 
  3568 *** Isar ***
  3569 
  3570 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3571   cut_tac, subgoal_tac and thin_tac:
  3572   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3573     locales are no longer forced to write Isar proof scripts.
  3574     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3575     emulations.
  3576   - INCOMPATIBILITY: names of variables to be instantiated may no
  3577     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3578     This is consistent with the instantiation attribute "where".
  3579 
  3580 * Attributes "where" and "of":
  3581   - Now take type variables of instantiated theorem into account when reading
  3582     the instantiation string.  This fixes a bug that caused instantiated
  3583     theorems to have too special types in some circumstances.
  3584   - "where" permits explicit instantiations of type variables.
  3585 
  3586 * Calculation commands "moreover" and "also" no longer interfere with
  3587   current facts ("this"), admitting arbitrary combinations with "then"
  3588   and derived forms.
  3589 
  3590 * Locales:
  3591   - Goal statements involving the context element "includes" no longer
  3592     generate theorems with internal delta predicates (those ending on
  3593     "_axioms") in the premise.
  3594     Resolve particular premise with <locale>.intro to obtain old form.
  3595   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3596     specification and "includes" elements in goal statement.
  3597   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3598     [intro?] and [elim?] (respectively) by default.
  3599   - Experimental command for instantiation of locales in proof contexts:
  3600         instantiate <label>[<attrs>]: <loc>
  3601     Instantiates locale <loc> and adds all its theorems to the current context
  3602     taking into account their attributes.  Label and attrs are optional
  3603     modifiers, like in theorem declarations.  If present, names of
  3604     instantiated theorems are qualified with <label>, and the attributes
  3605     <attrs> are applied after any attributes these theorems might have already.
  3606       If the locale has assumptions, a chained fact of the form
  3607     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3608     are derived.  The command does not support old-style locales declared
  3609     with "locale (open)".
  3610       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3611 
  3612 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3613   (Isar) contexts.
  3614 
  3615 
  3616 *** HOL ***
  3617 
  3618 * Proof import: new image HOL4 contains the imported library from
  3619   the HOL4 system with about 2500 theorems. It is imported by
  3620   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3621   can be used like any other Isabelle image.  See
  3622   HOL/Import/HOL/README for more information.
  3623 
  3624 * Simplifier:
  3625   - Much improved handling of linear and partial orders.
  3626     Reasoners for linear and partial orders are set up for type classes
  3627     "linorder" and "order" respectively, and are added to the default simpset
  3628     as solvers.  This means that the simplifier can build transitivity chains
  3629     to solve goals from the assumptions.
  3630   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3631     of blast or auto after simplification become unnecessary because the goal
  3632     is solved by simplification already.
  3633 
  3634 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3635     all proved in axiomatic type classes for semirings, rings and fields.
  3636 
  3637 * Numerics:
  3638   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3639     now formalized using the Ring_and_Field theory mentioned above.
  3640   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3641     than before, because now they are set up once in a generic manner.
  3642   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3643     Look for the general versions in Ring_and_Field (and Power if they concern
  3644     exponentiation).
  3645 
  3646 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3647 
  3648 * Records:
  3649   - Record types are now by default printed with their type abbreviation
  3650     instead of the list of all field types. This can be configured via
  3651     the reference "print_record_type_abbr".
  3652   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3653     (not enabled by default).
  3654   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3655     EX x. x = sel r to True (not enabled by default).
  3656   - Tactic "record_split_simp_tac" to split and simplify records added.
  3657 
  3658 * 'specification' command added, allowing for definition by
  3659   specification.  There is also an 'ax_specification' command that
  3660   introduces the new constants axiomatically.
  3661 
  3662 * arith(_tac) is now able to generate counterexamples for reals as well.
  3663 
  3664 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3665 
  3666 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3667   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3668 
  3669 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3670   matrix theory to linear programming.
  3671 
  3672 * Unions and Intersections:
  3673   The latex output syntax of UN and INT has been changed
  3674   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3675   i.e. the index formulae has become a subscript.
  3676   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3677 
  3678 * Unions and Intersections over Intervals:
  3679   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3680   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3681   like in normal math, and corresponding versions for < and for intersection.
  3682 
  3683 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3684   lexicographic dictonary ordering has been added as "lexord".
  3685 
  3686 * ML: the legacy theory structures Int and List have been removed. They had
  3687   conflicted with ML Basis Library structures having the same names.
  3688 
  3689 * 'refute' command added to search for (finite) countermodels.  Only works
  3690   for a fragment of HOL.  The installation of an external SAT solver is
  3691   highly recommended.  See "HOL/Refute.thy" for details.
  3692 
  3693 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3694   formulae under an assignment of free variables to random values.
  3695   In contrast to 'refute', it can deal with inductive datatypes,
  3696   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3697   for examples.
  3698 
  3699 
  3700 *** HOLCF ***
  3701 
  3702 * Streams now come with concatenation and are part of the HOLCF image
  3703 
  3704 
  3705 
  3706 New in Isabelle2003 (May 2003)
  3707 ------------------------------
  3708 
  3709 *** General ***
  3710 
  3711 * Provers/simplifier:
  3712 
  3713   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3714     Assumptions are now subject to complete mutual simplification,
  3715     not just from left to right. The simplifier now preserves
  3716     the order of assumptions.
  3717 
  3718     Potential INCOMPATIBILITY:
  3719 
  3720     -- simp sometimes diverges where the old version did
  3721        not, e.g. invoking simp on the goal
  3722 
  3723         [| P (f x); y = x; f x = f y |] ==> Q
  3724 
  3725        now gives rise to the infinite reduction sequence
  3726 
  3727         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3728 
  3729        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3730        kind of problem.
  3731 
  3732     -- Tactics combining classical reasoner and simplification (such as auto)
  3733        are also affected by this change, because many of them rely on
  3734        simp. They may sometimes diverge as well or yield a different numbers
  3735        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3736        in case of problems. Sometimes subsequent calls to the classical
  3737        reasoner will fail because a preceeding call to the simplifier too
  3738        eagerly simplified the goal, e.g. deleted redundant premises.
  3739 
  3740   - The simplifier trace now shows the names of the applied rewrite rules
  3741 
  3742   - You can limit the number of recursive invocations of the simplifier
  3743     during conditional rewriting (where the simplifie tries to solve the
  3744     conditions before applying the rewrite rule):
  3745     ML "simp_depth_limit := n"
  3746     where n is an integer. Thus you can force termination where previously
  3747     the simplifier would diverge.
  3748 
  3749   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3750 
  3751   - No longer aborts on failed congruence proof.  Instead, the
  3752     congruence is ignored.
  3753 
  3754 * Pure: New generic framework for extracting programs from constructive
  3755   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3756   as HOL/Extraction for some case studies.
  3757 
  3758 * Pure: The main goal of the proof state is no longer shown by default, only
  3759 the subgoals. This behaviour is controlled by a new flag.
  3760    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3761 (ML: Proof.show_main_goal).
  3762 
  3763 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3764 rules whose conclusion matches subgoal 1:
  3765       PG menu: Isabelle/Isar -> Show me -> matching rules
  3766 The rules are ordered by how closely they match the subgoal.
  3767 In particular, rules that solve a subgoal outright are displayed first
  3768 (or rather last, the way they are printed).
  3769 (ML: ProofGeneral.print_intros())
  3770 
  3771 * Pure: New flag trace_unify_fail causes unification to print
  3772 diagnostic information (PG: in trace buffer) when it fails. This is
  3773 useful for figuring out why single step proofs like rule, erule or
  3774 assumption failed.
  3775 
  3776 * Pure: Locale specifications now produce predicate definitions
  3777 according to the body of text (covering assumptions modulo local
  3778 definitions); predicate "loc_axioms" covers newly introduced text,
  3779 while "loc" is cumulative wrt. all included locale expressions; the
  3780 latter view is presented only on export into the global theory
  3781 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3782 on the old view without predicates;
  3783 
  3784 * Pure: predefined locales "var" and "struct" are useful for sharing
  3785 parameters (as in CASL, for example); just specify something like
  3786 ``var x + var y + struct M'' as import;
  3787 
  3788 * Pure: improved thms_containing: proper indexing of facts instead of
  3789 raw theorems; check validity of results wrt. current name space;
  3790 include local facts of proof configuration (also covers active
  3791 locales), cover fixed variables in index; may use "_" in term
  3792 specification; an optional limit for the number of printed facts may
  3793 be given (the default is 40);
  3794 
  3795 * Pure: disallow duplicate fact bindings within new-style theory files
  3796 (batch-mode only);
  3797 
  3798 * Provers: improved induct method: assumptions introduced by case
  3799 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3800 the goal statement); "foo" still refers to all facts collectively;
  3801 
  3802 * Provers: the function blast.overloaded has been removed: all constants
  3803 are regarded as potentially overloaded, which improves robustness in exchange
  3804 for slight decrease in efficiency;
  3805 
  3806 * Provers/linorder: New generic prover for transitivity reasoning over
  3807 linear orders.  Note: this prover is not efficient!
  3808 
  3809 * Isar: preview of problems to finish 'show' now produce an error
  3810 rather than just a warning (in interactive mode);
  3811 
  3812 
  3813 *** HOL ***
  3814 
  3815 * arith(_tac)
  3816 
  3817  - Produces a counter example if it cannot prove a goal.
  3818    Note that the counter example may be spurious if the goal is not a formula
  3819    of quantifier-free linear arithmetic.
  3820    In ProofGeneral the counter example appears in the trace buffer.
  3821 
  3822  - Knows about div k and mod k where k is a numeral of type nat or int.
  3823 
  3824  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3825    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3826    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3827 
  3828 * simp's arithmetic capabilities have been enhanced a bit: it now
  3829 takes ~= in premises into account (by performing a case split);
  3830 
  3831 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3832 are distributed over a sum of terms;
  3833 
  3834 * New tactic "trans_tac" and method "trans" instantiate
  3835 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3836 "<=", "<" and "=").
  3837 
  3838 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3839 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3840 
  3841 * 'typedef' command has new option "open" to suppress the set
  3842 definition;
  3843 
  3844 * functions Min and Max on finite sets have been introduced (theory
  3845 Finite_Set);
  3846 
  3847 * attribute [symmetric] now works for relations as well; it turns
  3848 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3849 
  3850 * induct over a !!-quantified statement (say !!x1..xn):
  3851   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3852 
  3853 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3854 %x. None. Warning: empty_def now refers to the previously hidden definition
  3855 of the empty set.
  3856 
  3857 * Algebra: formalization of classical algebra.  Intended as base for
  3858 any algebraic development in Isabelle.  Currently covers group theory
  3859 (up to Sylow's theorem) and ring theory (Universal Property of
  3860 Univariate Polynomials).  Contributions welcome;
  3861 
  3862 * GroupTheory: deleted, since its material has been moved to Algebra;
  3863 
  3864 * Complex: new directory of the complex numbers with numeric constants,
  3865 nonstandard complex numbers, and some complex analysis, standard and
  3866 nonstandard (Jacques Fleuriot);
  3867 
  3868 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3869 
  3870 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3871 Fleuriot);
  3872 
  3873 * Real/HahnBanach: updated and adapted to locales;
  3874 
  3875 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3876 Gray and Kramer);
  3877 
  3878 * UNITY: added the Meier-Sanders theory of progress sets;
  3879 
  3880 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3881 as abstract algorithms, instantiated to the JVM;
  3882 
  3883 * Bali: Java source language formalization. Type system, operational
  3884 semantics, axiomatic semantics. Supported language features:
  3885 classes, interfaces, objects,virtual methods, static methods,
  3886 static/instance fields, arrays, access modifiers, definite
  3887 assignment, exceptions.
  3888 
  3889 
  3890 *** ZF ***
  3891 
  3892 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3893 universe, etc.);
  3894 
  3895 * Main ZF: virtually all theories converted to new-style format;
  3896 
  3897 
  3898 *** ML ***
  3899 
  3900 * Pure: Tactic.prove provides sane interface for internal proofs;
  3901 omits the infamous "standard" operation, so this is more appropriate
  3902 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3903 
  3904 * Pure: improved error reporting of simprocs;
  3905 
  3906 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3907 up simprocs;
  3908 
  3909 
  3910 *** Document preparation ***
  3911 
  3912 * uses \par instead of \\ for line breaks in theory text. This may
  3913 shift some page breaks in large documents. To get the old behaviour
  3914 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3915 
  3916 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3917 other packages
  3918 
  3919 * \<euro> now needs package babel/greek instead of marvosym (which
  3920 broke \Rightarrow)
  3921 
  3922 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3923 textcomp package)
  3924 
  3925 
  3926 
  3927 New in Isabelle2002 (March 2002)
  3928 --------------------------------
  3929 
  3930 *** Document preparation ***
  3931 
  3932 * greatly simplified document preparation setup, including more
  3933 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3934 instructive isatool mkdir; users should basically be able to get
  3935 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3936 users may run a separate document processing stage manually like this:
  3937 "isatool usedir -D output HOL Test && isatool document Test/output";
  3938 
  3939 * theory dependency graph may now be incorporated into documents;
  3940 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3941 with \includegraphics of LaTeX;
  3942 
  3943 * proper spacing of consecutive markup elements, especially text
  3944 blocks after section headings;
  3945 
  3946 * support bold style (for single symbols only), input syntax is like
  3947 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3948 
  3949 * \<bullet> is now output as bold \cdot by default, which looks much
  3950 better in printed text;
  3951 
  3952 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3953 note that these symbols are currently unavailable in Proof General /
  3954 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3955 
  3956 * isatool latex no longer depends on changed TEXINPUTS, instead
  3957 isatool document copies the Isabelle style files to the target
  3958 location;
  3959 
  3960 
  3961 *** Isar ***
  3962 
  3963 * Pure/Provers: improved proof by cases and induction;
  3964   - 'case' command admits impromptu naming of parameters (such as
  3965     "case (Suc n)");
  3966   - 'induct' method divinates rule instantiation from the inductive
  3967     claim; no longer requires excessive ?P bindings for proper
  3968     instantiation of cases;
  3969   - 'induct' method properly enumerates all possibilities of set/type
  3970     rules; as a consequence facts may be also passed through *type*
  3971     rules without further ado;
  3972   - 'induct' method now derives symbolic cases from the *rulified*
  3973     rule (before it used to rulify cases stemming from the internal
  3974     atomized version); this means that the context of a non-atomic
  3975     statement becomes is included in the hypothesis, avoiding the
  3976     slightly cumbersome show "PROP ?case" form;
  3977   - 'induct' may now use elim-style induction rules without chaining
  3978     facts, using ``missing'' premises from the goal state; this allows
  3979     rules stemming from inductive sets to be applied in unstructured
  3980     scripts, while still benefitting from proper handling of non-atomic
  3981     statements; NB: major inductive premises need to be put first, all
  3982     the rest of the goal is passed through the induction;
  3983   - 'induct' proper support for mutual induction involving non-atomic
  3984     rule statements (uses the new concept of simultaneous goals, see
  3985     below);
  3986   - append all possible rule selections, but only use the first
  3987     success (no backtracking);
  3988   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3989   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3990   - added 'print_induct_rules' (covered by help item in recent Proof
  3991     General versions);
  3992   - moved induct/cases attributes to Pure, methods to Provers;
  3993   - generic method setup instantiated for FOL and HOL;
  3994 
  3995 * Pure: support multiple simultaneous goal statements, for example
  3996 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3997 meta-level mechanism, this acts as if several individual goals had
  3998 been stated separately; in particular common proof methods need to be
  3999 repeated in order to cover all claims; note that a single elimination
  4000 step is *not* sufficient to establish the two conjunctions, so this
  4001 fails:
  4002 
  4003   assume "A & B" then have A and B ..   (*".." fails*)
  4004 
  4005 better use "obtain" in situations as above; alternative refer to
  4006 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4007 
  4008 * Pure: proper integration with ``locales''; unlike the original
  4009 version by Florian Kammller, Isar locales package high-level proof
  4010 contexts rather than raw logical ones (e.g. we admit to include
  4011 attributes everywhere); operations on locales include merge and
  4012 rename; support for implicit arguments (``structures''); simultaneous
  4013 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4014 some examples;
  4015 
  4016 * Pure: the following commands have been ``localized'', supporting a
  4017 target locale specification "(in name)": 'lemma', 'theorem',
  4018 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4019 stored both within the locale and at the theory level (exported and
  4020 qualified by the locale name);
  4021 
  4022 * Pure: theory goals may now be specified in ``long'' form, with
  4023 ad-hoc contexts consisting of arbitrary locale elements. for example
  4024 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4025 definitions may be given, too); the result is a meta-level rule with
  4026 the context elements being discharged in the obvious way;
  4027 
  4028 * Pure: new proof command 'using' allows to augment currently used
  4029 facts after a goal statement ('using' is syntactically analogous to
  4030 'apply', but acts on the goal's facts only); this allows chained facts
  4031 to be separated into parts given before and after a claim, as in
  4032 ``from a and b have C using d and e <proof>'';
  4033 
  4034 * Pure: renamed "antecedent" case to "rule_context";
  4035 
  4036 * Pure: new 'judgment' command records explicit information about the
  4037 object-logic embedding (used by several tools internally); no longer
  4038 use hard-wired "Trueprop";
  4039 
  4040 * Pure: added 'corollary' command;
  4041 
  4042 * Pure: fixed 'token_translation' command;
  4043 
  4044 * Pure: removed obsolete 'exported' attribute;
  4045 
  4046 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4047 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4048 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4049 
  4050 * Pure: method 'atomize' presents local goal premises as object-level
  4051 statements (atomic meta-level propositions); setup controlled via
  4052 rewrite rules declarations of 'atomize' attribute; example
  4053 application: 'induct' method with proper rule statements in improper
  4054 proof *scripts*;
  4055 
  4056 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4057 now consider the syntactic context of assumptions, giving a better
  4058 chance to get type-inference of the arguments right (this is
  4059 especially important for locales);
  4060 
  4061 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4062 mode;
  4063 
  4064 * Pure/obtain: the formal conclusion "thesis", being marked as
  4065 ``internal'', may no longer be reference directly in the text;
  4066 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4067 situations;
  4068 
  4069 * Pure: generic 'sym' attribute which declares a rule both as pure
  4070 'elim?' and for the 'symmetric' operation;
  4071 
  4072 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4073 text; the fixed correlation with particular command syntax has been
  4074 discontinued;
  4075 
  4076 * Pure: new method 'rules' is particularly well-suited for proof
  4077 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4078 but often produces more compact proof terms with less detours;
  4079 
  4080 * Pure/Provers/classical: simplified integration with pure rule
  4081 attributes and methods; the classical "intro?/elim?/dest?"
  4082 declarations coincide with the pure ones; the "rule" method no longer
  4083 includes classically swapped intros; "intro" and "elim" methods no
  4084 longer pick rules from the context; also got rid of ML declarations
  4085 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4086 INCOMPATIBILITY;
  4087 
  4088 * Provers/classical: attribute 'swapped' produces classical inversions
  4089 of introduction rules;
  4090 
  4091 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4092 rules instead of full simplifier context; 'iff' attribute handles
  4093 conditional rules;
  4094 
  4095 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4096 
  4097 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4098 "(permissive)" option to recover old behavior;
  4099 
  4100 * HOL: 'inductive' no longer features separate (collective) attributes
  4101 for 'intros' (was found too confusing);
  4102 
  4103 * HOL: properly declared induction rules less_induct and
  4104 wf_induct_rule;
  4105 
  4106 
  4107 *** HOL ***
  4108 
  4109 * HOL: moved over to sane numeral syntax; the new policy is as
  4110 follows:
  4111 
  4112   - 0 and 1 are polymorphic constants, which are defined on any
  4113   numeric type (nat, int, real etc.);
  4114 
  4115   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4116   binary representation internally;
  4117 
  4118   - type nat has special constructor Suc, and generally prefers Suc 0
  4119   over 1::nat and Suc (Suc 0) over 2::nat;
  4120 
  4121 This change may cause significant problems of INCOMPATIBILITY; here
  4122 are some hints on converting existing sources:
  4123 
  4124   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4125   entities, so expressions involving "-" (unary or binary minus) need
  4126   to be spaced properly;
  4127 
  4128   - existing occurrences of "1" may need to be constraint "1::nat" or
  4129   even replaced by Suc 0; similar for old "2";
  4130 
  4131   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4132 
  4133   - remove all special provisions on numerals in proofs;
  4134 
  4135 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4136 representation (depends on bin_arith_simps in the default context);
  4137 
  4138 * HOL: symbolic syntax for x^2 (numeral 2);
  4139 
  4140 * HOL: the class of all HOL types is now called "type" rather than
  4141 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4142 in axclass/classes, instance/arities, and (usually rare) occurrences
  4143 in typings (of consts etc.); internally the class is called
  4144 "HOL.type", ML programs should refer to HOLogic.typeS;
  4145 
  4146 * HOL/record package improvements:
  4147   - new derived operations "fields" to build a partial record section,
  4148     "extend" to promote a fixed record to a record scheme, and
  4149     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4150     declared as simp by default;
  4151   - shared operations ("more", "fields", etc.) now need to be always
  4152     qualified) --- potential INCOMPATIBILITY;
  4153   - removed "make_scheme" operations (use "make" with "extend") --
  4154     INCOMPATIBILITY;
  4155   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4156   - provides cases/induct rules for use with corresponding Isar
  4157     methods (for concrete records, record schemes, concrete more
  4158     parts, and schematic more parts -- in that order);
  4159   - internal definitions directly based on a light-weight abstract
  4160     theory of product types over typedef rather than datatype;
  4161 
  4162 * HOL: generic code generator for generating executable ML code from
  4163 specifications; specific support for HOL constructs such as inductive
  4164 datatypes and sets, as well as recursive functions; can be invoked
  4165 via 'generate_code' theory section;
  4166 
  4167 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4168 
  4169 * HOL: consolidated and renamed several theories.  In particular:
  4170         Ord.thy has been absorbed into HOL.thy
  4171         String.thy has been absorbed into List.thy
  4172 
  4173 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4174 (beware of argument permutation!);
  4175 
  4176 * HOL: linorder_less_split superseded by linorder_cases;
  4177 
  4178 * HOL/List: "nodups" renamed to "distinct";
  4179 
  4180 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4181 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4182   - Ex_def has changed, now need to use some_eq_ex
  4183 
  4184 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4185 in this (rare) case use:
  4186 
  4187   delSWrapper "split_all_tac"
  4188   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4189 
  4190 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4191 MAY FAIL;
  4192 
  4193 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4194 Isabelle's type classes, ^ on functions and relations has too general
  4195 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4196 necessary to attach explicit type constraints;
  4197 
  4198 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4199 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4200 renamed accordingly (eg "compI" -> "rel_compI").
  4201 
  4202 * HOL: syntax translations now work properly with numerals and records
  4203 expressions;
  4204 
  4205 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4206 of "lam" -- INCOMPATIBILITY;
  4207 
  4208 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4209 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4210 renamed "Product_Type.unit";
  4211 
  4212 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4213 
  4214 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4215 the "cases" method);
  4216 
  4217 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4218 Florian Kammller);
  4219 
  4220 * HOL/IMP: updated and converted to new-style theory format; several
  4221 parts turned into readable document, with proper Isar proof texts and
  4222 some explanations (by Gerwin Klein);
  4223 
  4224 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4225 
  4226 * HOL-Hyperreal is now a logic image;
  4227 
  4228 
  4229 *** HOLCF ***
  4230 
  4231 * Isar: consts/constdefs supports mixfix syntax for continuous
  4232 operations;
  4233 
  4234 * Isar: domain package adapted to new-style theory format, e.g. see
  4235 HOLCF/ex/Dnat.thy;
  4236 
  4237 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4238 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4239 lift.induct_tac, always use UU instead of Undef;
  4240 
  4241 * HOLCF/IMP: updated and converted to new-style theory;
  4242 
  4243 
  4244 *** ZF ***
  4245 
  4246 * Isar: proper integration of logic-specific tools and packages,
  4247 including theory commands '(co)inductive', '(co)datatype',
  4248 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4249 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4250 
  4251 * theory Main no longer includes AC; for the Axiom of Choice, base
  4252 your theory on Main_ZFC;
  4253 
  4254 * the integer library now covers quotients and remainders, with many
  4255 laws relating division to addition, multiplication, etc.;
  4256 
  4257 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4258 typeless version of the formalism;
  4259 
  4260 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4261 format;
  4262 
  4263 * ZF/Induct: new directory for examples of inductive definitions,
  4264 including theory Multiset for multiset orderings; converted to
  4265 new-style theory format;
  4266 
  4267 * ZF: many new theorems about lists, ordinals, etc.;
  4268 
  4269 
  4270 *** General ***
  4271 
  4272 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4273 variable proof controls level of detail: 0 = no proofs (only oracle
  4274 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4275 also ref manual for further ML interfaces;
  4276 
  4277 * Pure/axclass: removed obsolete ML interface
  4278 goal_subclass/goal_arity;
  4279 
  4280 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4281 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4282 separate tokens, so expressions involving minus need to be spaced
  4283 properly;
  4284 
  4285 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4286 rather than "infixl" or "infixr";
  4287 
  4288 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4289 sort constraint specifications in type inference; e.g. "x::_::foo"
  4290 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4291 type variable);
  4292 
  4293 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4294 control output of nested => (types); the default behavior is
  4295 "type_brackets";
  4296 
  4297 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4298 tokens into AST constants;
  4299 
  4300 * Pure/syntax: prefer later declarations of translations and print
  4301 translation functions; potential INCOMPATIBILITY: need to reverse
  4302 multiple declarations for same syntax element constant;
  4303 
  4304 * Pure/show_hyps reset by default (in accordance to existing Isar
  4305 practice);
  4306 
  4307 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4308 addSafter;
  4309 
  4310 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4311 as well;
  4312 
  4313 * system: tested support for MacOS X; should be able to get Isabelle +
  4314 Proof General to work in a plain Terminal after installing Poly/ML
  4315 (e.g. from the Isabelle distribution area) and GNU bash alone
  4316 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4317 support requires further installations, e.g. from
  4318 http://fink.sourceforge.net/);
  4319 
  4320 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4321 
  4322 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4323 of 40 MB), cf. ML_OPTIONS;
  4324 
  4325 * system: Proof General keywords specification is now part of the
  4326 Isabelle distribution (see etc/isar-keywords.el);
  4327 
  4328 * system: support for persistent Proof General sessions (refrain from
  4329 outdating all loaded theories on startup); user may create writable
  4330 logic images like this: ``isabelle -q HOL Test'';
  4331 
  4332 * system: smart selection of Isabelle process versus Isabelle
  4333 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4334 run both "isabelle" and "Isabelle" even if file names are badly
  4335 damaged (executable inspects the case of the first letter of its own
  4336 name); added separate "isabelle-process" and "isabelle-interface";
  4337 
  4338 * system: refrain from any attempt at filtering input streams; no
  4339 longer support ``8bit'' encoding of old isabelle font, instead proper
  4340 iso-latin characters may now be used; the related isatools
  4341 "symbolinput" and "nonascii" have disappeared as well;
  4342 
  4343 * system: removed old "xterm" interface (the print modes "xterm" and
  4344 "xterm_color" are still available for direct use in a suitable
  4345 terminal);
  4346 
  4347 
  4348 
  4349 New in Isabelle99-2 (February 2001)
  4350 -----------------------------------
  4351 
  4352 *** Overview of INCOMPATIBILITIES ***
  4353 
  4354 * HOL: please note that theories in the Library and elsewhere often use the
  4355 new-style (Isar) format; to refer to their theorems in an ML script you must
  4356 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4357 
  4358 * HOL: inductive package no longer splits induction rule aggressively,
  4359 but only as far as specified by the introductions given; the old
  4360 format may be recovered via ML function complete_split_rule or attribute
  4361 'split_rule (complete)';
  4362 
  4363 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4364 gfp_Tarski to gfp_unfold;
  4365 
  4366 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4367 
  4368 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4369 relation); infix "^^" has been renamed "``"; infix "``" has been
  4370 renamed "`"; "univalent" has been renamed "single_valued";
  4371 
  4372 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4373 operation;
  4374 
  4375 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4376 
  4377 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4378 
  4379 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4380 consequence, it is no longer monotonic wrt. the local goal context
  4381 (which is now passed through the inductive cases);
  4382 
  4383 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4384 \<gg> to \<ggreater>;
  4385 
  4386 
  4387 *** Document preparation ***
  4388 
  4389 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4390 available: are "it" for near math-mode best-style output, "sl" for
  4391 slanted text style, and "tt" for plain type-writer; if no
  4392 \isabellestyle command is given, output is according to slanted
  4393 type-writer);
  4394 
  4395 * support sub/super scripts (for single symbols only), input syntax is
  4396 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4397 
  4398 * some more standard symbols; see Appendix A of the system manual for
  4399 the complete list of symbols defined in isabellesym.sty;
  4400 
  4401 * improved isabelle style files; more abstract symbol implementation
  4402 (should now use \isamath{...} and \isatext{...} in custom symbol
  4403 definitions);
  4404 
  4405 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4406 state; Note that presentation of goal states does not conform to
  4407 actual human-readable proof documents.  Please do not include goal
  4408 states into document output unless you really know what you are doing!
  4409 
  4410 * proper indentation of antiquoted output with proportional LaTeX
  4411 fonts;
  4412 
  4413 * no_document ML operator temporarily disables LaTeX document
  4414 generation;
  4415 
  4416 * isatool unsymbolize tunes sources for plain ASCII communication;
  4417 
  4418 
  4419 *** Isar ***
  4420 
  4421 * Pure: Isar now suffers initial goal statements to contain unbound
  4422 schematic variables (this does not conform to actual readable proof
  4423 documents, due to unpredictable outcome and non-compositional proof
  4424 checking); users who know what they are doing may use schematic goals
  4425 for Prolog-style synthesis of proven results;
  4426 
  4427 * Pure: assumption method (an implicit finishing) now handles actual
  4428 rules as well;
  4429 
  4430 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4431 initial goal, declare "that" only as Pure intro (only for single
  4432 steps); the "that" rule assumption may now be involved in implicit
  4433 finishing, thus ".." becomes a feasible for trivial obtains;
  4434 
  4435 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4436 instance proofs may be performed by "..";
  4437 
  4438 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4439 statements as well;
  4440 
  4441 * Pure: more robust selection of calculational rules;
  4442 
  4443 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4444 rule (as well as the assumption rule);
  4445 
  4446 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4447 lemmas, using the graph browser tool;
  4448 
  4449 * Pure: predict failure of "show" in interactive mode;
  4450 
  4451 * Pure: 'thms_containing' now takes actual terms as arguments;
  4452 
  4453 * HOL: improved method 'induct' --- now handles non-atomic goals
  4454 (potential INCOMPATIBILITY); tuned error handling;
  4455 
  4456 * HOL: cases and induct rules now provide explicit hints about the
  4457 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4458 any remaining facts are inserted into the goal verbatim;
  4459 
  4460 * HOL: local contexts (aka cases) may now contain term bindings as
  4461 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4462 the result to be shown in each case;
  4463 
  4464 * HOL: added 'recdef_tc' command;
  4465 
  4466 * isatool convert assists in eliminating legacy ML scripts;
  4467 
  4468 
  4469 *** HOL ***
  4470 
  4471 * HOL/Library: a collection of generic theories to be used together
  4472 with main HOL; the theory loader path already includes this directory
  4473 by default; the following existing theories have been moved here:
  4474 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4475 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4476 
  4477 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4478 modelling and verification task performed in Isabelle/HOL +
  4479 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4480 
  4481 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4482 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4483 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4484 'domain', this makes the theory consistent with mathematical
  4485 literature;
  4486 
  4487 * HOL basics: added overloaded operations "inverse" and "divide"
  4488 (infix "/"), syntax for generic "abs" operation, generic summation
  4489 operator \<Sum>;
  4490 
  4491 * HOL/typedef: simplified package, provide more useful rules (see also
  4492 HOL/subset.thy);
  4493 
  4494 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4495 now expressed as a proper nested rule (old-style tactic scripts may
  4496 require atomize_strip_tac to cope with non-atomic premises);
  4497 
  4498 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4499 to "split_conv" (old name still available for compatibility);
  4500 
  4501 * HOL: improved concrete syntax for strings (e.g. allows translation
  4502 rules with string literals);
  4503 
  4504 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4505  and Fleuriot's mechanization of analysis, including the transcendental
  4506  functions for the reals;
  4507 
  4508 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4509 
  4510 
  4511 *** CTT ***
  4512 
  4513 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4514 "lam" is displayed as TWO lambda-symbols
  4515 
  4516 * CTT: theory Main now available, containing everything (that is, Bool
  4517 and Arith);
  4518 
  4519 
  4520 *** General ***
  4521 
  4522 * Pure: the Simplifier has been implemented properly as a derived rule
  4523 outside of the actual kernel (at last!); the overall performance
  4524 penalty in practical applications is about 50%, while reliability of
  4525 the Isabelle inference kernel has been greatly improved;
  4526 
  4527 * print modes "brackets" and "no_brackets" control output of nested =>
  4528 (types) and ==> (props); the default behaviour is "brackets";
  4529 
  4530 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4531 as assumptions as well;
  4532 
  4533 * system: support Poly/ML 4.0;
  4534 
  4535 * system: isatool install handles KDE version 1 or 2;
  4536 
  4537 
  4538 
  4539 New in Isabelle99-1 (October 2000)
  4540 ----------------------------------
  4541 
  4542 *** Overview of INCOMPATIBILITIES ***
  4543 
  4544 * HOL: simplification of natural numbers is much changed; to partly
  4545 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4546 issue the following ML commands:
  4547 
  4548   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4549   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4550 
  4551 * HOL: simplification no longer dives into case-expressions; this is
  4552 controlled by "t.weak_case_cong" for each datatype t;
  4553 
  4554 * HOL: nat_less_induct renamed to less_induct;
  4555 
  4556 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4557 fixsome to patch .thy and .ML sources automatically;
  4558 
  4559   select_equality  -> some_equality
  4560   select_eq_Ex     -> some_eq_ex
  4561   selectI2EX       -> someI2_ex
  4562   selectI2         -> someI2
  4563   selectI          -> someI
  4564   select1_equality -> some1_equality
  4565   Eps_sym_eq       -> some_sym_eq_trivial
  4566   Eps_eq           -> some_eq_trivial
  4567 
  4568 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4569 
  4570 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4571 instead);
  4572 
  4573 * HOL: the recursion equations generated by 'recdef' are now called
  4574 f.simps instead of f.rules;
  4575 
  4576 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4577 
  4578 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4579 sometimes be needed;
  4580 
  4581 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4582 
  4583 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4584 
  4585 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4586 product is now "<*>" instead of "Times"; the lexicographic product is
  4587 now "<*lex*>" instead of "**";
  4588 
  4589 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4590 of main HOL, but was unused); better use HOL's datatype package;
  4591 
  4592 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4593 the old syntax may be recovered as follows:
  4594 
  4595   syntax (symbols)
  4596     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4597       (infixl "\\<oplus>" 100)
  4598 
  4599 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4600 
  4601 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4602 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4603 internally;
  4604 
  4605 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4606 changed from A/r to A//r;
  4607 
  4608 * ZF: new treatment of arithmetic (nat & int) may break some old
  4609 proofs;
  4610 
  4611 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4612 rulify -> rule_format, elimify -> elim_format, ...);
  4613 
  4614 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4615 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4616 should have to change intro!! to intro? only); replaced "delrule" by
  4617 "rule del";
  4618 
  4619 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4620 
  4621 * Provers: strengthened force_tac by using new first_best_tac;
  4622 
  4623 * LaTeX document preparation: several changes of isabelle.sty (see
  4624 lib/texinputs);
  4625 
  4626 
  4627 *** Document preparation ***
  4628 
  4629 * formal comments (text blocks etc.) in new-style theories may now
  4630 contain antiquotations of thm/prop/term/typ/text to be presented
  4631 according to latex print mode; concrete syntax is like this:
  4632 @{term[show_types] "f(x) = a + x"};
  4633 
  4634 * isatool mkdir provides easy setup of Isabelle session directories,
  4635 including proper document sources;
  4636 
  4637 * generated LaTeX sources are now deleted after successful run
  4638 (isatool document -c); may retain a copy somewhere else via -D option
  4639 of isatool usedir;
  4640 
  4641 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4642 style files, achieving self-contained LaTeX sources and simplifying
  4643 LaTeX debugging;
  4644 
  4645 * old-style theories now produce (crude) LaTeX output as well;
  4646 
  4647 * browser info session directories are now self-contained (may be put
  4648 on WWW server seperately); improved graphs of nested sessions; removed
  4649 graph for 'all sessions';
  4650 
  4651 * several improvements in isabelle style files; \isabellestyle{it}
  4652 produces fake math mode output; \isamarkupheader is now \section by
  4653 default; see lib/texinputs/isabelle.sty etc.;
  4654 
  4655 
  4656 *** Isar ***
  4657 
  4658 * Isar/Pure: local results and corresponding term bindings are now
  4659 subject to Hindley-Milner polymorphism (similar to ML); this
  4660 accommodates incremental type-inference very nicely;
  4661 
  4662 * Isar/Pure: new derived language element 'obtain' supports
  4663 generalized existence reasoning;
  4664 
  4665 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4666 support accumulation of results, without applying any rules yet;
  4667 useful to collect intermediate results without explicit name
  4668 references, and for use with transitivity rules with more than 2
  4669 premises;
  4670 
  4671 * Isar/Pure: scalable support for case-analysis type proofs: new
  4672 'case' language element refers to local contexts symbolically, as
  4673 produced by certain proof methods; internally, case names are attached
  4674 to theorems as "tags";
  4675 
  4676 * Isar/Pure: theory command 'hide' removes declarations from
  4677 class/type/const name spaces;
  4678 
  4679 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4680 indicate potential overloading;
  4681 
  4682 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4683 
  4684 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4685 "{a,b,c}" instead of {a,b,c};
  4686 
  4687 * Isar/Pure now provides its own version of intro/elim/dest
  4688 attributes; useful for building new logics, but beware of confusion
  4689 with the version in Provers/classical;
  4690 
  4691 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4692 case name 'antecedent';
  4693 
  4694 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4695 to the current context is now done automatically);
  4696 
  4697 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4698 for definining proof methods in ML;
  4699 
  4700 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4701 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4702 most cases, one should have to change intro!! to intro? only);
  4703 replaced "delrule" by "rule del";
  4704 
  4705 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4706 'symmetric' attribute (the latter supercedes [RS sym]);
  4707 
  4708 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4709 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4710 well (including splits);
  4711 
  4712 * Isar/Provers: Simplifier and Classical methods now support all kind
  4713 of modifiers used in the past, including 'cong', 'iff', etc.
  4714 
  4715 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4716 of Simplifier and Classical reasoner);
  4717 
  4718 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4719 now support named cases; major packages (inductive, datatype, primrec,
  4720 recdef) support case names and properly name parameters;
  4721 
  4722 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4723 monotonicity conditions are extracted to be proven at end of
  4724 calculations;
  4725 
  4726 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4727 method anyway;
  4728 
  4729 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4730 split_if split_if_asm; datatype package provides theorems foo.splits =
  4731 foo.split foo.split_asm for each datatype;
  4732 
  4733 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4734 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4735 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4736 use "(cases (simplified))" method in proper proof texts);
  4737 
  4738 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4739 
  4740 * Isar: names of theorems etc. may be natural numbers as well;
  4741 
  4742 * Isar: 'pr' command: optional arguments for goals_limit and
  4743 ProofContext.prems_limit; no longer prints theory contexts, but only
  4744 proof states;
  4745 
  4746 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4747 additional print modes to be specified; e.g. "pr(latex)" will print
  4748 proof state according to the Isabelle LaTeX style;
  4749 
  4750 * Isar: improved support for emulating tactic scripts, including proof
  4751 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4752 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4753 (for HOL datatypes);
  4754 
  4755 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4756 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4757 'proof method scripts' have to be in depth-first order;
  4758 
  4759 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4760 
  4761 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4762 should instead use individual commands for printing items
  4763 (print_commands, print_methods etc.);
  4764 
  4765 * Isar: added 'nothing' --- the empty list of theorems;
  4766 
  4767 
  4768 *** HOL ***
  4769 
  4770 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4771 corresponding virtual machine and a specification of its bytecode
  4772 verifier and a lightweight bytecode verifier, including proofs of
  4773 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4774 Cornelia Pusch (see also the homepage of project Bali at
  4775 http://isabelle.in.tum.de/Bali/);
  4776 
  4777 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4778 Clemens Ballarin;
  4779 
  4780 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4781 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4782 Rasmussen;
  4783 
  4784 * HOL/Lattice: fundamental concepts of lattice theory and order
  4785 structures, including duals, properties of bounds versus algebraic
  4786 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4787 Theorem for complete lattices etc.; may also serve as a demonstration
  4788 for abstract algebraic reasoning using axiomatic type classes, and
  4789 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4790 
  4791 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4792 von Oheimb;
  4793 
  4794 * HOL/IMPP: extension of IMP with local variables and mutually
  4795 recursive procedures, by David von Oheimb;
  4796 
  4797 * HOL/Lambda: converted into new-style theory and document;
  4798 
  4799 * HOL/ex/Multiquote: example of multiple nested quotations and
  4800 anti-quotations -- basically a generalized version of de-Bruijn
  4801 representation; very useful in avoiding lifting of operations;
  4802 
  4803 * HOL/record: added general record equality rule to simpset; fixed
  4804 select-update simplification procedure to handle extended records as
  4805 well; admit "r" as field name;
  4806 
  4807 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4808 other numeric types and also as the identity of groups, rings, etc.;
  4809 
  4810 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4811 Types nat and int belong to this axclass;
  4812 
  4813 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4814    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4815    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4816   two terms #m*u and #n*u are replaced by #(m+n)*u
  4817     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4818   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4819     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4820 
  4821 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4822 powerful prover for predicate logic but knows nothing of clasets; see
  4823 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4824 
  4825 * HOL: new version of "case_tac" subsumes both boolean case split and
  4826 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4827 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4828 
  4829 * HOL: simplification no longer dives into case-expressions: only the
  4830 selector expression is simplified, but not the remaining arms; to
  4831 enable full simplification of case-expressions for datatype t, you may
  4832 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4833 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4834 
  4835 * HOL/recdef: the recursion equations generated by 'recdef' for
  4836 function 'f' are now called f.simps instead of f.rules; if all
  4837 termination conditions are proved automatically, these simplification
  4838 rules are added to the simpset, as in primrec; rules may be named
  4839 individually as well, resulting in a separate list of theorems for
  4840 each equation;
  4841 
  4842 * HOL/While is a new theory that provides a while-combinator. It
  4843 permits the definition of tail-recursive functions without the
  4844 provision of a termination measure. The latter is necessary once the
  4845 invariant proof rule for while is applied.
  4846 
  4847 * HOL: new (overloaded) notation for the set of elements below/above
  4848 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4849 
  4850 * HOL: theorems impI, allI, ballI bound as "strip";
  4851 
  4852 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4853 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4854 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4855 
  4856 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4857 
  4858 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4859 main HOL, but was unused);
  4860 
  4861 * HOL: fewer consts declared as global (e.g. have to refer to
  4862 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4863 
  4864 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4865 in case of overlap with user translations (e.g. judgements over
  4866 tuples); (note that the underlying logical represenation is still
  4867 bogus);
  4868 
  4869 
  4870 *** ZF ***
  4871 
  4872 * ZF: simplification automatically cancels common terms in arithmetic
  4873 expressions over nat and int;
  4874 
  4875 * ZF: new treatment of nat to minimize type-checking: all operators
  4876 coerce their operands to a natural number using the function natify,
  4877 making the algebraic laws unconditional;
  4878 
  4879 * ZF: as above, for int: operators coerce their operands to an integer
  4880 using the function intify;
  4881 
  4882 * ZF: the integer library now contains many of the usual laws for the
  4883 orderings, including $<=, and monotonicity laws for $+ and $*;
  4884 
  4885 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4886 simplification;
  4887 
  4888 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4889 to the simplifier and classical reasoner simultaneously;
  4890 
  4891 
  4892 *** General ***
  4893 
  4894 * Provers: blast_tac now handles actual object-logic rules as
  4895 assumptions; note that auto_tac uses blast_tac internally as well;
  4896 
  4897 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4898 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4899 
  4900 * Provers: delrules now handles destruct rules as well (no longer need
  4901 explicit make_elim);
  4902 
  4903 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4904   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4905 use instead the strong form,
  4906   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4907 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4908 from destruct-rules;
  4909 
  4910 * Provers: Simplifier.easy_setup provides a fast path to basic
  4911 Simplifier setup for new object-logics;
  4912 
  4913 * Pure: AST translation rules no longer require constant head on LHS;
  4914 
  4915 * Pure: improved name spaces: ambiguous output is qualified; support
  4916 for hiding of names;
  4917 
  4918 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4919 XSYMBOL_HOME; no longer need to do manual configuration in most
  4920 situations;
  4921 
  4922 * system: compression of ML heaps images may now be controlled via -c
  4923 option of isabelle and isatool usedir (currently only observed by
  4924 Poly/ML);
  4925 
  4926 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4927 useful for remote X11);
  4928 
  4929 * system: provide TAGS file for Isabelle sources;
  4930 
  4931 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4932 order;
  4933 
  4934 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4935 timing flag supersedes proof_timing and Toplevel.trace;
  4936 
  4937 * ML: new combinators |>> and |>>> for incremental transformations
  4938 with secondary results (e.g. certain theory extensions):
  4939 
  4940 * ML: PureThy.add_defs gets additional argument to indicate potential
  4941 overloading (usually false);
  4942 
  4943 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4944 results;
  4945 
  4946 
  4947 
  4948 New in Isabelle99 (October 1999)
  4949 --------------------------------
  4950 
  4951 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4952 
  4953 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4954 are no longer simplified.  (This allows the simplifier to unfold recursive
  4955 functional programs.)  To restore the old behaviour, declare
  4956 
  4957     Delcongs [if_weak_cong];
  4958 
  4959 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4960 complement;
  4961 
  4962 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4963 
  4964 * HOL/datatype: mutual_induct_tac no longer exists --
  4965   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  4966 
  4967 * HOL/typedef: fixed type inference for representing set; type
  4968 arguments now have to occur explicitly on the rhs as type constraints;
  4969 
  4970 * ZF: The con_defs part of an inductive definition may no longer refer
  4971 to constants declared in the same theory;
  4972 
  4973 * HOL, ZF: the function mk_cases, generated by the inductive
  4974 definition package, has lost an argument.  To simplify its result, it
  4975 uses the default simpset instead of a supplied list of theorems.
  4976 
  4977 * HOL/List: the constructors of type list are now Nil and Cons;
  4978 
  4979 * Simplifier: the type of the infix ML functions
  4980         setSSolver addSSolver setSolver addSolver
  4981 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4982 for packaging solvers. A solver is created via
  4983         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4984 where the string argument is only a comment.
  4985 
  4986 
  4987 *** Proof tools ***
  4988 
  4989 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4990 decision procedure for linear arithmetic. Currently it is used for
  4991 types `nat', `int', and `real' in HOL (see below); it can, should and
  4992 will be instantiated for other types and logics as well.
  4993 
  4994 * The simplifier now accepts rewrite rules with flexible heads, eg
  4995      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4996   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4997   matching.
  4998 
  4999 
  5000 *** General ***
  5001 
  5002 * New Isabelle/Isar subsystem provides an alternative to traditional
  5003 tactical theorem proving; together with the ProofGeneral/isar user
  5004 interface it offers an interactive environment for developing human
  5005 readable proof documents (Isar == Intelligible semi-automated
  5006 reasoning); for further information see isatool doc isar-ref,
  5007 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5008 
  5009 * improved and simplified presentation of theories: better HTML markup
  5010 (including colors), graph views in several sizes; isatool usedir now
  5011 provides a proper interface for user theories (via -P option); actual
  5012 document preparation based on (PDF)LaTeX is available as well (for
  5013 new-style theories only); see isatool doc system for more information;
  5014 
  5015 * native support for Proof General, both for classic Isabelle and
  5016 Isabelle/Isar;
  5017 
  5018 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5019 using the graph browser tool;
  5020 
  5021 * Isabelle manuals now also available as PDF;
  5022 
  5023 * theory loader rewritten from scratch (may not be fully
  5024 bug-compatible); old loadpath variable has been replaced by show_path,
  5025 add_path, del_path, reset_path functions; new operations such as
  5026 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5027 isatool doc ref);
  5028 
  5029 * improved isatool install: option -k creates KDE application icon,
  5030 option -p DIR installs standalone binaries;
  5031 
  5032 * added ML_PLATFORM setting (useful for cross-platform installations);
  5033 more robust handling of platform specific ML images for SML/NJ;
  5034 
  5035 * the settings environment is now statically scoped, i.e. it is never
  5036 created again in sub-processes invoked from isabelle, isatool, or
  5037 Isabelle;
  5038 
  5039 * path element specification '~~' refers to '$ISABELLE_HOME';
  5040 
  5041 * in locales, the "assumes" and "defines" parts may be omitted if
  5042 empty;
  5043 
  5044 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5045 long arrows);
  5046 
  5047 * new print_mode "HTML";
  5048 
  5049 * new flag show_tags controls display of tags of theorems (which are
  5050 basically just comments that may be attached by some tools);
  5051 
  5052 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5053 mode and goal output format:
  5054 
  5055 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5056 244c244
  5057 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5058 ---
  5059 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5060 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5061 181c181
  5062 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5063 ---
  5064 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5065 
  5066 * function bind_thms stores lists of theorems (cf. bind_thm);
  5067 
  5068 * new shorthand tactics ftac, eatac, datac, fatac;
  5069 
  5070 * qed (and friends) now accept "" as result name; in that case the
  5071 theorem is not stored, but proper checks and presentation of the
  5072 result still apply;
  5073 
  5074 * theorem database now also indexes constants "Trueprop", "all",
  5075 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5076 
  5077 
  5078 *** HOL ***
  5079 
  5080 ** HOL arithmetic **
  5081 
  5082 * There are now decision procedures for linear arithmetic over nat and
  5083 int:
  5084 
  5085 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5086 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5087 are treated as atomic; subformulae not involving type `nat' or `int'
  5088 are ignored; quantified subformulae are ignored unless they are
  5089 positive universal or negative existential. The tactic has to be
  5090 invoked by hand and can be a little bit slow. In particular, the
  5091 running time is exponential in the number of occurrences of `min' and
  5092 `max', and `-' on `nat'.
  5093 
  5094 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5095 (negated) (in)equalities among the premises and the conclusion into
  5096 account (i.e. no compound formulae) and does not know about `min' and
  5097 `max', and `-' on `nat'. It is fast and is used automatically by the
  5098 simplifier.
  5099 
  5100 NB: At the moment, these decision procedures do not cope with mixed
  5101 nat/int formulae where the two parts interact, such as `m < n ==>
  5102 int(m) < int(n)'.
  5103 
  5104 * HOL/Numeral provides a generic theory of numerals (encoded
  5105 efficiently as bit strings); setup for types nat/int/real is in place;
  5106 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5107 int, existing theories and proof scripts may require a few additional
  5108 type constraints;
  5109 
  5110 * integer division and remainder can now be performed on constant
  5111 arguments;
  5112 
  5113 * many properties of integer multiplication, division and remainder
  5114 are now available;
  5115 
  5116 * An interface to the Stanford Validity Checker (SVC) is available through the
  5117 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5118 are proved automatically.  SVC must be installed separately, and its results
  5119 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5120 invocation of the underlying oracle).  For SVC see
  5121   http://verify.stanford.edu/SVC
  5122 
  5123 * IsaMakefile: the HOL-Real target now builds an actual image;
  5124 
  5125 
  5126 ** HOL misc **
  5127 
  5128 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5129 (in Isabelle/Isar) -- by Gertrud Bauer;
  5130 
  5131 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5132 analysis for assembly languages with subtypes;
  5133 
  5134 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5135 -- avoids syntactic ambiguities and treats state, transition, and
  5136 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5137 changed syntax and (many) tactics;
  5138 
  5139 * HOL/inductive: Now also handles more general introduction rules such
  5140   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5141   theorems are now maintained within the theory (maintained via the
  5142   "mono" attribute);
  5143 
  5144 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5145   (using function types) such as
  5146 
  5147   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5148 
  5149 * HOL/record: record_simproc (part of the default simpset) takes care
  5150 of selectors applied to updated records; record_split_tac is no longer
  5151 part of the default claset; update_defs may now be removed from the
  5152 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5153 
  5154   claset_ref () := claset() addSWrapper record_split_wrapper;
  5155   Delsimprocs [record_simproc]
  5156 
  5157 * HOL/typedef: fixed type inference for representing set; type
  5158 arguments now have to occur explicitly on the rhs as type constraints;
  5159 
  5160 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5161 names rather than an ML expression;
  5162 
  5163 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5164 supplied later.  Program schemes can be defined, such as
  5165     "While B C s = (if B s then While B C (C s) else s)"
  5166 where the well-founded relation can be chosen after B and C have been given.
  5167 
  5168 * HOL/List: the constructors of type list are now Nil and Cons;
  5169 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5170 course, ML tools referring to List.list.op # etc. have to be adapted;
  5171 
  5172 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5173 disabled by default; run isabelle with option -m HOL to get back to
  5174 the original Gordon/HOL-style output;
  5175 
  5176 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5177 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5178 
  5179 * HOL basic syntax simplified (more orthogonal): all variants of
  5180 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5181 Eps operator is provided as well: "SOME x. P[x]";
  5182 
  5183 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5184 
  5185 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5186 thus available for user theories;
  5187 
  5188 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5189 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5190 time;
  5191 
  5192 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5193 several times and then mp;
  5194 
  5195 
  5196 *** LK ***
  5197 
  5198 * the notation <<...>> is now available as a notation for sequences of
  5199 formulas;
  5200 
  5201 * the simplifier is now installed
  5202 
  5203 * the axiom system has been generalized (thanks to Soren Heilmann)
  5204 
  5205 * the classical reasoner now has a default rule database
  5206 
  5207 
  5208 *** ZF ***
  5209 
  5210 * new primrec section allows primitive recursive functions to be given
  5211 directly (as in HOL) over datatypes and the natural numbers;
  5212 
  5213 * new tactics induct_tac and exhaust_tac for induction (or case
  5214 analysis) over datatypes and the natural numbers;
  5215 
  5216 * the datatype declaration of type T now defines the recursor T_rec;
  5217 
  5218 * simplification automatically does freeness reasoning for datatype
  5219 constructors;
  5220 
  5221 * automatic type-inference, with AddTCs command to insert new
  5222 type-checking rules;
  5223 
  5224 * datatype introduction rules are now added as Safe Introduction rules
  5225 to the claset;
  5226 
  5227 * the syntax "if P then x else y" is now available in addition to
  5228 if(P,x,y);
  5229 
  5230 
  5231 *** Internal programming interfaces ***
  5232 
  5233 * tuned simplifier trace output; new flag debug_simp;
  5234 
  5235 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5236 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5237 
  5238 * AxClass.axclass_tac lost the theory argument;
  5239 
  5240 * tuned current_goals_markers semantics: begin / end goal avoids
  5241 printing empty lines;
  5242 
  5243 * removed prs and prs_fn hook, which was broken because it did not
  5244 include \n in its semantics, forcing writeln to add one
  5245 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5246 string -> unit if you really want to output text without newline;
  5247 
  5248 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5249 plain output, interface builders may have to enable 'isabelle_font'
  5250 mode to get Isabelle font glyphs as before;
  5251 
  5252 * refined token_translation interface; INCOMPATIBILITY: output length
  5253 now of type real instead of int;
  5254 
  5255 * theory loader actions may be traced via new ThyInfo.add_hook
  5256 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5257 your own database of information attached to *whole* theories -- as
  5258 opposed to intra-theory data slots offered via TheoryDataFun;
  5259 
  5260 * proper handling of dangling sort hypotheses (at last!);
  5261 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5262 extra sort hypotheses that can be witnessed from the type signature;
  5263 the force_strip_shyps flag is gone, any remaining shyps are simply
  5264 left in the theorem (with a warning issued by strip_shyps_warning);
  5265 
  5266 
  5267 
  5268 New in Isabelle98-1 (October 1998)
  5269 ----------------------------------
  5270 
  5271 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5272 
  5273 * several changes of automated proof tools;
  5274 
  5275 * HOL: major changes to the inductive and datatype packages, including
  5276 some minor incompatibilities of theory syntax;
  5277 
  5278 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5279 called `inj_on';
  5280 
  5281 * HOL: removed duplicate thms in Arith:
  5282   less_imp_add_less  should be replaced by  trans_less_add1
  5283   le_imp_add_le      should be replaced by  trans_le_add1
  5284 
  5285 * HOL: unary minus is now overloaded (new type constraints may be
  5286 required);
  5287 
  5288 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5289 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5290 now taken as an integer constant.
  5291 
  5292 * Pure: ML function 'theory_of' renamed to 'theory';
  5293 
  5294 
  5295 *** Proof tools ***
  5296 
  5297 * Simplifier:
  5298   1. Asm_full_simp_tac is now more aggressive.
  5299      1. It will sometimes reorient premises if that increases their power to
  5300         simplify.
  5301      2. It does no longer proceed strictly from left to right but may also
  5302         rotate premises to achieve further simplification.
  5303      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5304      old Asm_full_simp_tac in that it does not rotate premises.
  5305   2. The simplifier now knows a little bit about nat-arithmetic.
  5306 
  5307 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5308 allows for selected deletion of wrappers, by introduction of names for
  5309 wrapper functionals.  This implies that addbefore, addSbefore,
  5310 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5311 and that adding two tactics with the same name overwrites the first
  5312 one (emitting a warning).
  5313   type wrapper = (int -> tactic) -> (int -> tactic)
  5314   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5315   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5316   delWrapper, delSWrapper: claset *  string            -> claset
  5317   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5318 
  5319 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5320 semantics; addbefore now affects only the unsafe part of step_tac
  5321 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5322 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5323 by Force_tac;
  5324 
  5325 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5326 compWrapper; added safe wrapper (and access functions for it);
  5327 
  5328 * HOL/split_all_tac is now much faster and fails if there is nothing
  5329 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5330 and the names of the automatically generated variables have changed.
  5331 split_all_tac has moved within claset() from unsafe wrappers to safe
  5332 wrappers, which means that !!-bound variables are split much more
  5333 aggressively, and safe_tac and clarify_tac now split such variables.
  5334 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5335 Note: the same holds for record_split_tac, which does the job of
  5336 split_all_tac for record fields.
  5337 
  5338 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5339 permanently to the default simpset using Addsplits just like
  5340 Addsimps. They can be removed via Delsplits just like
  5341 Delsimps. Lower-case versions are also available.
  5342 
  5343 * HOL/Simplifier: The rule split_if is now part of the default
  5344 simpset. This means that the simplifier will eliminate all occurrences
  5345 of if-then-else in the conclusion of a goal. To prevent this, you can
  5346 either remove split_if completely from the default simpset by
  5347 `Delsplits [split_if]' or remove it in a specific call of the
  5348 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5349 other case splitting rules to/from the default simpset: every datatype
  5350 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5351 t is the name of the datatype).
  5352 
  5353 * Classical reasoner / Simplifier combination: new force_tac (and
  5354 derivatives Force_tac, force) combines rewriting and classical
  5355 reasoning (and whatever other tools) similarly to auto_tac, but is
  5356 aimed to solve the given subgoal completely.
  5357 
  5358 
  5359 *** General ***
  5360 
  5361 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5362 and `goalw': the theory is no longer needed as an explicit argument -
  5363 the current theory context is used; assumptions are no longer returned
  5364 at the ML-level unless one of them starts with ==> or !!; it is
  5365 recommended to convert to these new commands using isatool fixgoal
  5366 (backup your sources first!);
  5367 
  5368 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5369 the current theory context, and 'theory' to lookup stored theories;
  5370 
  5371 * new theory section 'locale' for declaring constants, assumptions and
  5372 definitions that have local scope;
  5373 
  5374 * new theory section 'nonterminals' for purely syntactic types;
  5375 
  5376 * new theory section 'setup' for generic ML setup functions
  5377 (e.g. package initialization);
  5378 
  5379 * the distribution now includes Isabelle icons: see
  5380 lib/logo/isabelle-{small,tiny}.xpm;
  5381 
  5382 * isatool install - install binaries with absolute references to
  5383 ISABELLE_HOME/bin;
  5384 
  5385 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5386 
  5387 * print mode 'emacs' reserved for Isamode;
  5388 
  5389 * support multiple print (ast) translations per constant name;
  5390 
  5391 * theorems involving oracles are now printed with a suffixed [!];
  5392 
  5393 
  5394 *** HOL ***
  5395 
  5396 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5397 
  5398 * HOL/inductive package reorganized and improved: now supports mutual
  5399 definitions such as
  5400 
  5401   inductive EVEN ODD
  5402     intrs
  5403       null "0 : EVEN"
  5404       oddI "n : EVEN ==> Suc n : ODD"
  5405       evenI "n : ODD ==> Suc n : EVEN"
  5406 
  5407 new theorem list "elims" contains an elimination rule for each of the
  5408 recursive sets; inductive definitions now handle disjunctive premises
  5409 correctly (also ZF);
  5410 
  5411 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5412 "mutual_induct" no longer exists - the induction rule is always
  5413 contained in "induct";
  5414 
  5415 
  5416 * HOL/datatype package re-implemented and greatly improved: now
  5417 supports mutually recursive datatypes such as
  5418 
  5419   datatype
  5420     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5421             | SUM ('a aexp) ('a aexp)
  5422             | DIFF ('a aexp) ('a aexp)
  5423             | NUM 'a
  5424   and
  5425     'a bexp = LESS ('a aexp) ('a aexp)
  5426             | AND ('a bexp) ('a bexp)
  5427             | OR ('a bexp) ('a bexp)
  5428 
  5429 as well as indirectly recursive datatypes such as
  5430 
  5431   datatype
  5432     ('a, 'b) term = Var 'a
  5433                   | App 'b ((('a, 'b) term) list)
  5434 
  5435 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5436 induction on mutually / indirectly recursive datatypes.
  5437 
  5438 Primrec equations are now stored in theory and can be accessed via
  5439 <function_name>.simps.
  5440 
  5441 INCOMPATIBILITIES:
  5442 
  5443   - Theories using datatypes must now have theory Datatype as an
  5444     ancestor.
  5445   - The specific <typename>.induct_tac no longer exists - use the
  5446     generic induct_tac instead.
  5447   - natE has been renamed to nat.exhaust - use exhaust_tac
  5448     instead of res_inst_tac ... natE. Note that the variable
  5449     names in nat.exhaust differ from the names in natE, this
  5450     may cause some "fragile" proofs to fail.
  5451   - The theorems split_<typename>_case and split_<typename>_case_asm
  5452     have been renamed to <typename>.split and <typename>.split_asm.
  5453   - Since default sorts of type variables are now handled correctly,
  5454     some datatype definitions may have to be annotated with explicit
  5455     sort constraints.
  5456   - Primrec definitions no longer require function name and type
  5457     of recursive argument.
  5458 
  5459 Consider using isatool fixdatatype to adapt your theories and proof
  5460 scripts to the new package (backup your sources first!).
  5461 
  5462 
  5463 * HOL/record package: considerably improved implementation; now
  5464 includes concrete syntax for record types, terms, updates; theorems
  5465 for surjective pairing and splitting !!-bound record variables; proof
  5466 support is as follows:
  5467 
  5468   1) standard conversions (selectors or updates applied to record
  5469 constructor terms) are part of the standard simpset;
  5470 
  5471   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5472 made part of standard simpset and claset via addIffs;
  5473 
  5474   3) a tactic for record field splitting (record_split_tac) is part of
  5475 the standard claset (addSWrapper);
  5476 
  5477 To get a better idea about these rules you may retrieve them via
  5478 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5479 the name of your record type.
  5480 
  5481 The split tactic 3) conceptually simplifies by the following rule:
  5482 
  5483   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5484 
  5485 Thus any record variable that is bound by meta-all will automatically
  5486 blow up into some record constructor term, consequently the
  5487 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5488 solve record problems automatically.
  5489 
  5490 
  5491 * reorganized the main HOL image: HOL/Integ and String loaded by
  5492 default; theory Main includes everything;
  5493 
  5494 * automatic simplification of integer sums and comparisons, using cancellation;
  5495 
  5496 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5497 
  5498 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5499 
  5500 * many new identities for unions, intersections, set difference, etc.;
  5501 
  5502 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5503 called split_if, split_split, split_sum_case and split_nat_case (to go
  5504 with add/delsplits);
  5505 
  5506 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5507 (?x::unit) = (); this is made part of the default simpset, which COULD
  5508 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5509 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5510 unit_abs_eta_conv is added in order to counter the effect of
  5511 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5512 %u.f();
  5513 
  5514 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5515 makes more sense);
  5516 
  5517 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5518   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5519   disjointness reasoning but breaking a few old proofs.
  5520 
  5521 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5522 to 'converse' from 'inverse' (for compatibility with ZF and some
  5523 literature);
  5524 
  5525 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5526 the well-founded relation;
  5527 
  5528 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5529     Compl A.  The "Compl" syntax remains available as input syntax for this
  5530     release ONLY.
  5531 
  5532 * HOL/Update: new theory of function updates:
  5533     f(a:=b) == %x. if x=a then b else f x
  5534 may also be iterated as in f(a:=b,c:=d,...);
  5535 
  5536 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5537 
  5538 * HOL/List:
  5539   - new function list_update written xs[i:=v] that updates the i-th
  5540     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5541   - new function `upt' written [i..j(] which generates the list
  5542     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5543     bound write [i..j], which is a shorthand for [i..j+1(].
  5544   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5545 
  5546 * HOL/Arith:
  5547   - removed 'pred' (predecessor) function;
  5548   - generalized some theorems about n-1;
  5549   - many new laws about "div" and "mod";
  5550   - new laws about greatest common divisors (see theory ex/Primes);
  5551 
  5552 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5553 instead of "inverse";
  5554 
  5555 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5556   of the multiset ordering;
  5557 
  5558 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5559   (not included by default);
  5560 
  5561 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5562 
  5563 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5564   programs, i.e. different program variables may have different types.
  5565 
  5566 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5567   [previously, this check worked only if the rewrite rule was unconditional]
  5568   Now rew can involve either definitions or equalities (either == or =).
  5569 
  5570 
  5571 *** ZF ***
  5572 
  5573 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5574   only the theorems proved on ZF.ML;
  5575 
  5576 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5577   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5578   disjointness reasoning but breaking a few old proofs.
  5579 
  5580 * ZF/Update: new theory of function updates
  5581     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5582   may also be iterated as in f(a:=b,c:=d,...);
  5583 
  5584 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5585 
  5586 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5587   [previously, this check worked only if the rewrite rule was unconditional]
  5588   Now rew can involve either definitions or equalities (either == or =).
  5589 
  5590 * case_tac provided for compatibility with HOL
  5591     (like the old excluded_middle_tac, but with subgoals swapped)
  5592 
  5593 
  5594 *** Internal programming interfaces ***
  5595 
  5596 * Pure: several new basic modules made available for general use, see
  5597 also src/Pure/README;
  5598 
  5599 * improved the theory data mechanism to support encapsulation (data
  5600 kind name replaced by private Object.kind, acting as authorization
  5601 key); new type-safe user interface via functor TheoryDataFun; generic
  5602 print_data function becomes basically useless;
  5603 
  5604 * removed global_names compatibility flag -- all theory declarations
  5605 are qualified by default;
  5606 
  5607 * module Pure/Syntax now offers quote / antiquote translation
  5608 functions (useful for Hoare logic etc. with implicit dependencies);
  5609 see HOL/ex/Antiquote for an example use;
  5610 
  5611 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5612 cterm -> thm;
  5613 
  5614 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5615 subgoal;
  5616 
  5617 * Display.print_goals function moved to Locale.print_goals;
  5618 
  5619 * standard print function for goals supports current_goals_markers
  5620 variable for marking begin of proof, end of proof, start of goal; the
  5621 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5622 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5623 for example;
  5624 
  5625 
  5626 
  5627 New in Isabelle98 (January 1998)
  5628 --------------------------------
  5629 
  5630 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5631 
  5632 * changed lexical syntax of terms / types: dots made part of long
  5633 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5634 
  5635 * simpset (and claset) reference variable replaced by functions
  5636 simpset / simpset_ref;
  5637 
  5638 * no longer supports theory aliases (via merge) and non-trivial
  5639 implicit merge of thms' signatures;
  5640 
  5641 * most internal names of constants changed due to qualified names;
  5642 
  5643 * changed Pure/Sequence interface (see Pure/seq.ML);
  5644 
  5645 
  5646 *** General Changes ***
  5647 
  5648 * hierachically structured name spaces (for consts, types, axms, thms
  5649 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5650 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5651 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5652 long_names for fully qualified output names; NOTE: ML programs
  5653 (special tactics, packages etc.) referring to internal names may have
  5654 to be adapted to cope with fully qualified names; in case of severe
  5655 backward campatibility problems try setting 'global_names' at compile
  5656 time to have enrything declared within a flat name space; one may also
  5657 fine tune name declarations in theories via the 'global' and 'local'
  5658 section;
  5659 
  5660 * reimplemented the implicit simpset and claset using the new anytype
  5661 data filed in signatures; references simpset:simpset ref etc. are
  5662 replaced by functions simpset:unit->simpset and
  5663 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5664 to patch your ML files accordingly;
  5665 
  5666 * HTML output now includes theory graph data for display with Java
  5667 applet or isatool browser; data generated automatically via isatool
  5668 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5669 
  5670 * defs may now be conditional; improved rewrite_goals_tac to handle
  5671 conditional equations;
  5672 
  5673 * defs now admits additional type arguments, using TYPE('a) syntax;
  5674 
  5675 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5676 creates a new theory node; implicit merge of thms' signatures is
  5677 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5678 transfer:theory->thm->thm in (rare) cases;
  5679 
  5680 * improved handling of draft signatures / theories; draft thms (and
  5681 ctyps, cterms) are automatically promoted to real ones;
  5682 
  5683 * slightly changed interfaces for oracles: admit many per theory, named
  5684 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5685 
  5686 * print_goals: optional output of const types (set show_consts and
  5687 show_types);
  5688 
  5689 * improved output of warnings (###) and errors (***);
  5690 
  5691 * subgoal_tac displays a warning if the new subgoal has type variables;
  5692 
  5693 * removed old README and Makefiles;
  5694 
  5695 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5696 
  5697 * removed obsolete init_pps and init_database;
  5698 
  5699 * deleted the obsolete tactical STATE, which was declared by
  5700     fun STATE tacfun st = tacfun st st;
  5701 
  5702 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5703 (which abbreviates $HOME);
  5704 
  5705 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5706 use isatool fixseq to adapt your ML programs (this works for fully
  5707 qualified references to the Sequence structure only!);
  5708 
  5709 * use_thy no longer requires writable current directory; it always
  5710 reloads .ML *and* .thy file, if either one is out of date;
  5711 
  5712 
  5713 *** Classical Reasoner ***
  5714 
  5715 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5716 tactics that use classical reasoning to simplify a subgoal without
  5717 splitting it into several subgoals;
  5718 
  5719 * Safe_tac: like safe_tac but uses the default claset;
  5720 
  5721 
  5722 *** Simplifier ***
  5723 
  5724 * added simplification meta rules:
  5725     (asm_)(full_)simplify: simpset -> thm -> thm;
  5726 
  5727 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5728 logics (again);
  5729 
  5730 * added prems argument to simplification procedures;
  5731 
  5732 * HOL, FOL, ZF: added infix function `addsplits':
  5733   instead of `<simpset> setloop (split_tac <thms>)'
  5734   you can simply write `<simpset> addsplits <thms>'
  5735 
  5736 
  5737 *** Syntax ***
  5738 
  5739 * TYPE('a) syntax for type reflection terms;
  5740 
  5741 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5742 
  5743 * pretty printer: changed order of mixfix annotation preference (again!);
  5744 
  5745 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5746 
  5747 
  5748 *** HOL ***
  5749 
  5750 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5751   with `addloop' of the simplifier to faciliate case splitting in premises.
  5752 
  5753 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5754 
  5755 * HOL/Auth: new protocol proofs including some for the Internet
  5756   protocol TLS;
  5757 
  5758 * HOL/Map: new theory of `maps' a la VDM;
  5759 
  5760 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5761 cancelling out common nat summands from =, <, <= (in)equalities, or
  5762 differences; simplification procedures nat_cancel_factor for
  5763 cancelling common factor from =, <, <= (in)equalities over natural
  5764 sums; nat_cancel contains both kinds of procedures, it is installed by
  5765 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5766 
  5767 * HOL/simplifier: terms of the form
  5768   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5769   are rewritten to
  5770   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5771   and those of the form
  5772   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5773   are rewritten to
  5774   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5775 
  5776 * HOL/datatype
  5777   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5778 
  5779   P(t_case f1 ... fn x) =
  5780      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5781         ...
  5782        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5783      )
  5784 
  5785   and a theorem `split_t_case_asm' of the form
  5786 
  5787   P(t_case f1 ... fn x) =
  5788     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5789         ...
  5790        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5791      )
  5792   which can be added to a simpset via `addsplits'. The existing theorems
  5793   expand_list_case and expand_option_case have been renamed to
  5794   split_list_case and split_option_case.
  5795 
  5796 * HOL/Arithmetic:
  5797   - `pred n' is automatically converted to `n-1'.
  5798     Users are strongly encouraged not to use `pred' any longer,
  5799     because it will disappear altogether at some point.
  5800   - Users are strongly encouraged to write "0 < n" rather than
  5801     "n ~= 0". Theorems and proof tools have been modified towards this
  5802     `standard'.
  5803 
  5804 * HOL/Lists:
  5805   the function "set_of_list" has been renamed "set" (and its theorems too);
  5806   the function "nth" now takes its arguments in the reverse order and
  5807   has acquired the infix notation "!" as in "xs!n".
  5808 
  5809 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5810 
  5811 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5812   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5813 
  5814 * HOL/record: extensible records with schematic structural subtyping
  5815 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5816 still lacks various theorems and concrete record syntax;
  5817 
  5818 
  5819 *** HOLCF ***
  5820 
  5821 * removed "axioms" and "generated by" sections;
  5822 
  5823 * replaced "ops" section by extended "consts" section, which is capable of
  5824   handling the continuous function space "->" directly;
  5825 
  5826 * domain package:
  5827   . proves theorems immediately and stores them in the theory,
  5828   . creates hierachical name space,
  5829   . now uses normal mixfix annotations (instead of cinfix...),
  5830   . minor changes to some names and values (for consistency),
  5831   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5832   . separator between mutual domain defs: changed "," to "and",
  5833   . improved handling of sort constraints;  now they have to
  5834     appear on the left-hand side of the equations only;
  5835 
  5836 * fixed LAM <x,y,zs>.b syntax;
  5837 
  5838 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5839 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5840 
  5841 
  5842 *** FOL and ZF ***
  5843 
  5844 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5845   with `addloop' of the simplifier to faciliate case splitting in premises.
  5846 
  5847 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5848 in HOL, they strip ALL and --> from proved theorems;
  5849 
  5850 
  5851 
  5852 New in Isabelle94-8 (May 1997)
  5853 ------------------------------
  5854 
  5855 *** General Changes ***
  5856 
  5857 * new utilities to build / run / maintain Isabelle etc. (in parts
  5858 still somewhat experimental); old Makefiles etc. still functional;
  5859 
  5860 * new 'Isabelle System Manual';
  5861 
  5862 * INSTALL text, together with ./configure and ./build scripts;
  5863 
  5864 * reimplemented type inference for greater efficiency, better error
  5865 messages and clean internal interface;
  5866 
  5867 * prlim command for dealing with lots of subgoals (an easier way of
  5868 setting goals_limit);
  5869 
  5870 
  5871 *** Syntax ***
  5872 
  5873 * supports alternative (named) syntax tables (parser and pretty
  5874 printer); internal interface is provided by add_modesyntax(_i);
  5875 
  5876 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5877 be used in conjunction with the Isabelle symbol font; uses the
  5878 "symbols" syntax table;
  5879 
  5880 * added token_translation interface (may translate name tokens in
  5881 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5882 the current print_mode); IMPORTANT: user print translation functions
  5883 are responsible for marking newly introduced bounds
  5884 (Syntax.mark_boundT);
  5885 
  5886 * token translations for modes "xterm" and "xterm_color" that display
  5887 names in bold, underline etc. or colors (which requires a color
  5888 version of xterm);
  5889 
  5890 * infixes may now be declared with names independent of their syntax;
  5891 
  5892 * added typed_print_translation (like print_translation, but may
  5893 access type of constant);
  5894 
  5895 
  5896 *** Classical Reasoner ***
  5897 
  5898 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5899 some limitations.  Blast_tac...
  5900   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5901   + ignores elimination rules that don't have the correct format
  5902         (the conclusion MUST be a formula variable)
  5903   + ignores types, which can make HOL proofs fail
  5904   + rules must not require higher-order unification, e.g. apply_type in ZF
  5905     [message "Function Var's argument not a bound variable" relates to this]
  5906   + its proof strategy is more general but can actually be slower
  5907 
  5908 * substitution with equality assumptions no longer permutes other
  5909 assumptions;
  5910 
  5911 * minor changes in semantics of addafter (now called addaltern); renamed
  5912 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5913 (and access functions for it);
  5914 
  5915 * improved combination of classical reasoner and simplifier:
  5916   + functions for handling clasimpsets
  5917   + improvement of addss: now the simplifier is called _after_ the
  5918     safe steps.
  5919   + safe variant of addss called addSss: uses safe simplifications
  5920     _during_ the safe steps. It is more complete as it allows multiple
  5921     instantiations of unknowns (e.g. with slow_tac).
  5922 
  5923 *** Simplifier ***
  5924 
  5925 * added interface for simplification procedures (functions that
  5926 produce *proven* rewrite rules on the fly, depending on current
  5927 redex);
  5928 
  5929 * ordering on terms as parameter (used for ordered rewriting);
  5930 
  5931 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5932 
  5933 * the solver is now split into a safe and an unsafe part.
  5934 This should be invisible for the normal user, except that the
  5935 functions setsolver and addsolver have been renamed to setSolver and
  5936 addSolver; added safe_asm_full_simp_tac;
  5937 
  5938 
  5939 *** HOL ***
  5940 
  5941 * a generic induction tactic `induct_tac' which works for all datatypes and
  5942 also for type `nat';
  5943 
  5944 * a generic case distinction tactic `exhaust_tac' which works for all
  5945 datatypes and also for type `nat';
  5946 
  5947 * each datatype comes with a function `size';
  5948 
  5949 * patterns in case expressions allow tuple patterns as arguments to
  5950 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5951 
  5952 * primrec now also works with type nat;
  5953 
  5954 * recdef: a new declaration form, allows general recursive functions to be
  5955 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5956 
  5957 * the constant for negation has been renamed from "not" to "Not" to
  5958 harmonize with FOL, ZF, LK, etc.;
  5959 
  5960 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5961 infinite lists;
  5962 
  5963 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5964 
  5965 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  5966 problems in commutative rings, using axiomatic type classes for + and *;
  5967 
  5968 * more examples in HOL/MiniML and HOL/Auth;
  5969 
  5970 * more default rewrite rules for quantifiers, union/intersection;
  5971 
  5972 * a new constant `arbitrary == @x.False';
  5973 
  5974 * HOLCF/IOA replaces old HOL/IOA;
  5975 
  5976 * HOLCF changes: derived all rules and arities
  5977   + axiomatic type classes instead of classes
  5978   + typedef instead of faking type definitions
  5979   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5980   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5981   + eliminated the types void, one, tr
  5982   + use unit lift and bool lift (with translations) instead of one and tr
  5983   + eliminated blift from Lift3.thy (use Def instead of blift)
  5984   all eliminated rules are derived as theorems --> no visible changes ;
  5985 
  5986 
  5987 *** ZF ***
  5988 
  5989 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5990 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5991 as ZF_cs addSIs [equalityI];
  5992 
  5993 
  5994 
  5995 New in Isabelle94-7 (November 96)
  5996 ---------------------------------
  5997 
  5998 * allowing negative levels (as offsets) in prlev and choplev;
  5999 
  6000 * super-linear speedup for large simplifications;
  6001 
  6002 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6003 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6004 FAIL); can suppress it using the command Delsimps (ex_simps @
  6005 all_simps); De Morgan laws are also now included, by default;
  6006 
  6007 * improved printing of ==>  :  ~:
  6008 
  6009 * new object-logic "Sequents" adds linear logic, while replacing LK
  6010 and Modal (thanks to Sara Kalvala);
  6011 
  6012 * HOL/Auth: correctness proofs for authentication protocols;
  6013 
  6014 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6015 examples on HOL/Auth);
  6016 
  6017 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6018 the rewriter and classical reasoner simultaneously;
  6019 
  6020 * function uresult no longer returns theorems in "standard" format;
  6021 regain previous version by: val uresult = standard o uresult;
  6022 
  6023 
  6024 
  6025 New in Isabelle94-6
  6026 -------------------
  6027 
  6028 * oracles -- these establish an interface between Isabelle and trusted
  6029 external reasoners, which may deliver results as theorems;
  6030 
  6031 * proof objects (in particular record all uses of oracles);
  6032 
  6033 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6034 
  6035 * "constdefs" section in theory files;
  6036 
  6037 * "primrec" section (HOL) no longer requires names;
  6038 
  6039 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6040 
  6041 
  6042 
  6043 New in Isabelle94-5
  6044 -------------------
  6045 
  6046 * reduced space requirements;
  6047 
  6048 * automatic HTML generation from theories;
  6049 
  6050 * theory files no longer require "..." (quotes) around most types;
  6051 
  6052 * new examples, including two proofs of the Church-Rosser theorem;
  6053 
  6054 * non-curried (1994) version of HOL is no longer distributed;
  6055 
  6056 
  6057 
  6058 New in Isabelle94-4
  6059 -------------------
  6060 
  6061 * greatly reduced space requirements;
  6062 
  6063 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6064 
  6065 * searchable theorem database (see the section "Retrieving theorems" on
  6066 page 8 of the Reference Manual);
  6067 
  6068 * new examples, including Grabczewski's monumental case study of the
  6069 Axiom of Choice;
  6070 
  6071 * The previous version of HOL renamed to Old_HOL;
  6072 
  6073 * The new version of HOL (previously called CHOL) uses a curried syntax
  6074 for functions.  Application looks like f a b instead of f(a,b);
  6075 
  6076 * Mutually recursive inductive definitions finally work in HOL;
  6077 
  6078 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6079 translates to the operator "split";
  6080 
  6081 
  6082 
  6083 New in Isabelle94-3
  6084 -------------------
  6085 
  6086 * new infix operator, addss, allowing the classical reasoner to
  6087 perform simplification at each step of its search.  Example:
  6088         fast_tac (cs addss ss)
  6089 
  6090 * a new logic, CHOL, the same as HOL, but with a curried syntax
  6091 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  6092 look like (a,b) instead of <a,b>;
  6093 
  6094 * PLEASE NOTE: CHOL will eventually replace HOL!
  6095 
  6096 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  6097 It translates to the operator "split".  A new theory of integers is available;
  6098 
  6099 * In ZF, integer numerals now denote two's-complement binary integers.
  6100 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  6101 
  6102 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  6103 of the Axiom of Choice;
  6104 
  6105 
  6106 
  6107 New in Isabelle94-2
  6108 -------------------
  6109 
  6110 * Significantly faster resolution;
  6111 
  6112 * the different sections in a .thy file can now be mixed and repeated
  6113 freely;
  6114 
  6115 * Database of theorems for FOL, HOL and ZF.  New
  6116 commands including qed, qed_goal and bind_thm store theorems in the database.
  6117 
  6118 * Simple database queries: return a named theorem (get_thm) or all theorems of
  6119 a given theory (thms_of), or find out what theory a theorem was proved in
  6120 (theory_of_thm);
  6121 
  6122 * Bugs fixed in the inductive definition and datatype packages;
  6123 
  6124 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  6125 and HOL_dup_cs obsolete;
  6126 
  6127 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  6128 have been removed;
  6129 
  6130 * Simpler definition of function space in ZF;
  6131 
  6132 * new results about cardinal and ordinal arithmetic in ZF;
  6133 
  6134 * 'subtype' facility in HOL for introducing new types as subsets of existing
  6135 types;
  6136 
  6137 :mode=text:wrap=hard:maxLineLen=72: