NEWS
author haftmann
Fri Mar 27 10:05:13 2009 +0100 (2009-03-27)
changeset 30740 2d3ae5a7edb2
parent 30706 e20227b5e6a3
child 30741 9e23e3ea7edd
permissions -rw-r--r--
dropped toy example Code_Antiq
     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 * Module moves in repository:
    79     src/Pure/Tools/value.ML ~> src/Tools/
    80     src/Pure/Tools/quickcheck.ML ~> src/Tools/
    81 
    82 * Slightly more coherent Pure syntax, with updated documentation in
    83 isar-ref manual.  Removed locales meta_term_syntax and
    84 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
    85 INCOMPATIBILITY in rare situations.
    86 
    87 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
    88 hypotheses.  Sorts required in the course of reasoning need to be
    89 covered by the constraints in the initial statement, completed by the
    90 type instance information of the background theory.  Non-trivial sort
    91 hypotheses, which rarely occur in practice, may be specified via
    92 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
    93 
    94   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
    95 
    96 The result contains an implicit sort hypotheses as before --
    97 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
    98 normalization.
    99 
   100 * Changed defaults for unify configuration options:
   101 
   102   unify_trace_bound = 50 (formerly 25)
   103   unify_search_bound = 60 (formerly 30)
   104 
   105 * Different bookkeeping for code equations (INCOMPATIBILITY):
   106 
   107   a) On theory merge, the last set of code equations for a particular
   108      constant is taken (in accordance with the policy applied by other
   109      parts of the code generator framework).
   110 
   111   b) Code equations stemming from explicit declarations (e.g. code
   112      attribute) gain priority over default code equations stemming
   113      from definition, primrec, fun etc.
   114 
   115 * Global versions of theorems stemming from classes do not carry a
   116 parameter prefix any longer.  INCOMPATIBILITY.
   117 
   118 * Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   119 In existing theorem specifications replace the includes element by the
   120 respective context elements of the included locale, omitting those
   121 that are already present in the theorem specification.  Multiple
   122 assume elements of a locale should be replaced by a single one
   123 involving the locale predicate.  In the proof body, declarations (most
   124 notably theorems) may be regained by interpreting the respective
   125 locales in the proof context as required (command "interpret").
   126 
   127 If using "includes" in replacement of a target solely because the
   128 parameter types in the theorem are not as general as in the target,
   129 consider declaring a new locale with additional type constraints on
   130 the parameters (context element "constrains").
   131 
   132 * Dropped "locale (open)".  INCOMPATIBILITY.
   133 
   134 * Interpretation commands no longer attempt to simplify goal.
   135 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   136 methods intro_locales and unfold_locales to clarify.
   137 
   138 * Interpretation commands no longer accept interpretation attributes.
   139 INCOMPATBILITY.
   140 
   141 * Complete re-implementation of locales.  INCOMPATIBILITY.  The most
   142 important changes are listed below.  See documentation (forthcoming)
   143 and tutorial (also forthcoming) for details.
   144 
   145 - In locale expressions, instantiation replaces renaming.  Parameters
   146 must be declared in a for clause.  To aid compatibility with previous
   147 parameter inheritance, in locale declarations, parameters that are not
   148 'touched' (instantiation position "_" or omitted) are implicitly added
   149 with their syntax at the beginning of the for clause.
   150 
   151 - Syntax from abbreviations and definitions in locales is available in
   152 locale expressions and context elements.  The latter is particularly
   153 useful in locale declarations.
   154 
   155 - More flexible mechanisms to qualify names generated by locale
   156 expressions.  Qualifiers (prefixes) may be specified in locale
   157 expressions.  Available are normal qualifiers (syntax "name:") and
   158 strict qualifiers (syntax "name!:").  The latter must occur in name
   159 references and are useful to avoid accidental hiding of names, the
   160 former are optional.  Qualifiers derived from the parameter names of a
   161 locale are no longer generated.
   162 
   163 - "sublocale l < e" replaces "interpretation l < e".  The
   164 instantiation clause in "interpretation" and "interpret" (square
   165 brackets) is no longer available.  Use locale expressions.
   166 
   167 - When converting proof scripts, be sure to replace qualifiers in
   168 "interpretation" and "interpret" by strict qualifiers.  Qualifiers in
   169 locale expressions range over a single locale instance only.
   170 
   171 * Command 'instance': attached definitions no longer accepted.
   172 INCOMPATIBILITY, use proper 'instantiation' target.
   173 
   174 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   175 
   176 * The 'axiomatization' command now only works within a global theory
   177 context.  INCOMPATIBILITY.
   178 
   179 * New 'find_theorems' criterion "solves" matching theorems that
   180 directly solve the current goal.
   181 
   182 * Auto solve feature for main theorem statements (cf. option in Proof
   183 General Isabelle settings menu, enabled by default).  Whenever a new
   184 goal is stated, "find_theorems solves" is called; any theorems that
   185 could solve the lemma directly are listed underneath the goal.
   186 
   187 * Command 'find_consts' searches for constants based on type and name
   188 patterns, e.g.
   189 
   190     find_consts "_ => bool"
   191 
   192 By default, matching is against subtypes, but it may be restricted to
   193 the whole type. Searching by name is possible.  Multiple queries are
   194 conjunctive and queries may be negated by prefixing them with a
   195 hyphen:
   196 
   197     find_consts strict: "_ => bool" name: "Int" -"int => int"
   198 
   199 * Command 'local_setup' is similar to 'setup', but operates on a local
   200 theory context.
   201 
   202 
   203 *** Document preparation ***
   204 
   205 * Antiquotation @{lemma} now imitates a regular terminal proof,
   206 demanding keyword 'by' and supporting the full method expression
   207 syntax just like the Isar command 'by'.
   208 
   209 
   210 *** HOL ***
   211 
   212 * Theory Library/Polynomial.thy defines an abstract type 'a poly of
   213 univariate polynomials with coefficients of type 'a.  In addition to
   214 the standard ring operations, it also supports div and mod.  Code
   215 generation is also supported, using list-style constructors.
   216 
   217 * Theory Library/Inner_Product.thy defines a class of real_inner for
   218 real inner product spaces, with an overloaded operation inner :: 'a =>
   219 'a => real.  Class real_inner is a subclass of real_normed_vector from
   220 RealVector.thy.
   221 
   222 * Theory Library/Product_Vector.thy provides instances for the product
   223 type 'a * 'b of several classes from RealVector.thy and
   224 Inner_Product.thy.  Definitions of addition, subtraction, scalar
   225 multiplication, norms, and inner products are included.
   226 
   227 * Theory Library/Bit.thy defines the field "bit" of integers modulo 2.
   228 In addition to the field operations, numerals and case syntax are also
   229 supported.
   230 
   231 * Theory Library/Diagonalize.thy provides constructive version of
   232 Cantor's first diagonalization argument.
   233 
   234 * New predicate "strict_mono" classifies strict functions on partial orders.
   235 With strict functions on linear orders, reasoning about (in)equalities is
   236 facilitated by theorems "strict_mono_eq", "strict_mono_less_eq" and "strict_mono_less".
   237 
   238 * Some set operations are now proper qualified constants with authentic syntax.
   239 INCOMPATIBILITY:
   240 
   241     op Int ~>   Set.Int
   242     op Un ~>    Set.Un
   243     INTER ~>    Set.INTER
   244     UNION ~>    Set.UNION
   245     Inter ~>    Set.Inter
   246     Union ~>    Set.Union
   247     {} ~>       Set.empty
   248     UNIV ~>     Set.UNIV
   249 
   250 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in theory
   251 Set.
   252 
   253 * Auxiliary class "itself" has disappeared -- classes without any parameter
   254 are treated as expected by the 'class' command.
   255 
   256 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   257 
   258 * Common decision procedures (Cooper, MIR, Ferrack, Approximation, Dense_Linear_Order)
   259 now in directory HOL/Decision_Procs.
   260 
   261 * Theory HOL/Decision_Procs/Approximation.thy provides the new proof method
   262 "approximation".  It proves formulas on real values by using interval arithmetic.
   263 In the formulas are also the transcendental functions sin, cos, tan, atan, ln,
   264 exp and the constant pi are allowed. For examples see
   265 HOL/Descision_Procs/ex/Approximation_Ex.thy.
   266 
   267 * Theory "Reflection" now resides in HOL/Library.
   268 
   269 * Entry point to Word library now simply named "Word".  INCOMPATIBILITY.
   270 
   271 * Made source layout more coherent with logical distribution
   272 structure:
   273 
   274     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   275     src/HOL/Library/Code_Message.thy ~> src/HOL/
   276     src/HOL/Library/GCD.thy ~> src/HOL/
   277     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   278     src/HOL/Library/Parity.thy ~> src/HOL/
   279     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   280     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   281     src/HOL/Real/Lubs.thy ~> src/HOL/
   282     src/HOL/Real/PReal.thy ~> src/HOL/
   283     src/HOL/Real/Rational.thy ~> src/HOL/
   284     src/HOL/Real/RComplete.thy ~> src/HOL/
   285     src/HOL/Real/RealDef.thy ~> src/HOL/
   286     src/HOL/Real/RealPow.thy ~> src/HOL/
   287     src/HOL/Real/Real.thy ~> src/HOL/
   288     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   289     src/HOL/Complex/Complex.thy ~> src/HOL/
   290     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   291     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   292     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   293     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   294     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   295     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   296     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   297     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   298     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   299     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   300     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   301     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   302     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   303     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   304     src/HOL/Real/Float ~> src/HOL/Library/
   305     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   306     src/HOL/Real/RealVector.thy ~> src/HOL/
   307 
   308     src/HOL/arith_data.ML ~> src/HOL/Tools
   309     src/HOL/hologic.ML ~> src/HOL/Tools
   310     src/HOL/simpdata.ML ~> src/HOL/Tools
   311     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   312     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   313     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   314     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   315     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   316     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   317     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   318 
   319     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   320     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   321     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   322     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   323     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   324     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   325 
   326 * If methods "eval" and "evaluation" encounter a structured proof state
   327 with !!/==>, only the conclusion is evaluated to True (if possible),
   328 avoiding strange error messages.
   329 
   330 * Simplifier: simproc for let expressions now unfolds if bound variable
   331 occurs at most once in let expression body.  INCOMPATIBILITY.
   332 
   333 * New attribute "arith" for facts that should always be used automaticaly
   334 by arithmetic. It is intended to be used locally in proofs, eg
   335 assumes [arith]: "x > 0"
   336 Global usage is discouraged because of possible performance impact.
   337 
   338 * New classes "top" and "bot" with corresponding operations "top" and "bot"
   339 in theory Orderings;  instantiation of class "complete_lattice" requires
   340 instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   341 
   342 * Changed definition lemma "less_fun_def" in order to provide an instance
   343 for preorders on functions;  use lemma "less_le" instead.  INCOMPATIBILITY.
   344 
   345 * Unified theorem tables for both code code generators.  Thus
   346 [code func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   347 
   348 * Constants "undefined" and "default" replace "arbitrary".  Usually
   349 "undefined" is the right choice to replace "arbitrary", though logically
   350 there is no difference.  INCOMPATIBILITY.
   351 
   352 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   353 Posix processes.  Avoids potentially expensive forking of the ML
   354 process.  New thread-based implementation also works on non-Unix
   355 platforms (Cygwin).  Provers are no longer hardwired, but defined
   356 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   357 commands are covered in the isar-ref manual.
   358 
   359 * Wrapper scripts for remote SystemOnTPTP service allows to use
   360 sledgehammer without local ATP installation (Vampire etc.). Other
   361 provers may be included via suitable ML wrappers, see also
   362 src/HOL/ATP_Linkup.thy.
   363 
   364 * Normalization by evaluation now allows non-leftlinear equations.
   365 Declare with attribute [code nbe].
   366 
   367 * Command "value" now integrates different evaluation
   368 mechanisms.  The result of the first successful evaluation mechanism
   369 is printed.  In square brackets a particular named evaluation
   370 mechanisms may be specified (currently, [SML], [code] or [nbe]).  See
   371 further src/HOL/ex/Eval_Examples.thy.
   372 
   373 * New method "sizechange" to automate termination proofs using (a
   374 modification of) the size-change principle. Requires SAT solver. See
   375 src/HOL/ex/Termination.thy for examples.
   376 
   377 * HOL/Orderings: class "wellorder" moved here, with explicit induction
   378 rule "less_induct" as assumption.  For instantiation of "wellorder" by
   379 means of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.
   380 
   381 * HOL/Orderings: added class "preorder" as superclass of "order".
   382 INCOMPATIBILITY: Instantiation proofs for order, linorder
   383 etc. slightly changed.  Some theorems named order_class.* now named
   384 preorder_class.*.
   385 
   386 * HOL/Relation:
   387 Renamed "refl" to "refl_on", "reflexive" to "refl, "diag" to "Id_on".
   388 
   389 * HOL/Finite_Set: added a new fold combinator of type
   390   ('a => 'b => 'b) => 'b => 'a set => 'b
   391 Occasionally this is more convenient than the old fold combinator which is
   392 now defined in terms of the new one and renamed to fold_image.
   393 
   394 * HOL/Ring_and_Field and HOL/OrderedGroup: The lemmas "group_simps" and
   395 "ring_simps" have been replaced by "algebra_simps" (which can be extended with
   396 further lemmas!). At the moment both still exist but the former will disappear
   397 at some point.
   398 
   399 * HOL/Power: Lemma power_Suc is now declared as a simp rule in class
   400 recpower.  Type-specific simp rules for various recpower types have
   401 been removed.  INCOMPATIBILITY.  Rename old lemmas as follows:
   402 
   403 rat_power_0    -> power_0
   404 rat_power_Suc  -> power_Suc
   405 realpow_0      -> power_0
   406 realpow_Suc    -> power_Suc
   407 complexpow_0   -> power_0
   408 complexpow_Suc -> power_Suc
   409 power_poly_0   -> power_0
   410 power_poly_Suc -> power_Suc
   411 
   412 * HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
   413 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   414 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   415 of lemmas from Divides has been generalized from nat to class
   416 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   417 renames resulting from duplicate elimination:
   418 
   419     dvd_def_mod ~>          dvd_eq_mod_eq_0
   420     zero_dvd_iff ~>         dvd_0_left_iff
   421     dvd_0 ~>                dvd_0_right
   422     DIVISION_BY_ZERO_DIV ~> div_by_0
   423     DIVISION_BY_ZERO_MOD ~> mod_by_0
   424     mult_div ~>             div_mult_self2_is_id
   425     mult_mod ~>             mod_mult_self2_is_0
   426 
   427 * HOL/IntDiv: removed many lemmas that are instances of class-based
   428 generalizations (from Divides and Ring_and_Field).
   429 INCOMPATIBILITY. Rename old lemmas as follows:
   430 
   431 dvd_diff               -> nat_dvd_diff
   432 dvd_zminus_iff         -> dvd_minus_iff
   433 mod_add1_eq            -> mod_add_eq
   434 mod_mult1_eq           -> mod_mult_right_eq
   435 mod_mult1_eq'          -> mod_mult_left_eq
   436 mod_mult_distrib_mod   -> mod_mult_eq
   437 nat_mod_add_left_eq    -> mod_add_left_eq
   438 nat_mod_add_right_eq   -> mod_add_right_eq
   439 nat_mod_div_trivial    -> mod_div_trivial
   440 nat_mod_mod_trivial    -> mod_mod_trivial
   441 zdiv_zadd_self1        -> div_add_self1
   442 zdiv_zadd_self2        -> div_add_self2
   443 zdiv_zmult_self1       -> div_mult_self2_is_id
   444 zdiv_zmult_self2       -> div_mult_self1_is_id
   445 zdvd_triv_left         -> dvd_triv_left
   446 zdvd_triv_right        -> dvd_triv_right
   447 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   448 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   449 zmod_zadd_left_eq      -> mod_add_left_eq
   450 zmod_zadd_right_eq     -> mod_add_right_eq
   451 zmod_zadd_self1        -> mod_add_self1
   452 zmod_zadd_self2        -> mod_add_self2
   453 zmod_zadd1_eq          -> mod_add_eq
   454 zmod_zdiff1_eq         -> mod_diff_eq
   455 zmod_zdvd_zmod         -> mod_mod_cancel
   456 zmod_zmod_cancel       -> mod_mod_cancel
   457 zmod_zmult_self1       -> mod_mult_self2_is_0
   458 zmod_zmult_self2       -> mod_mult_self1_is_0
   459 zmod_1                 -> mod_by_1
   460 zdiv_1                 -> div_by_1
   461 zdvd_abs1              -> abs_dvd_iff
   462 zdvd_abs2              -> dvd_abs_iff
   463 zdvd_refl              -> dvd_refl
   464 zdvd_trans             -> dvd_trans
   465 zdvd_zadd              -> dvd_add
   466 zdvd_zdiff             -> dvd_diff
   467 zdvd_zminus_iff        -> dvd_minus_iff
   468 zdvd_zminus2_iff       -> minus_dvd_iff
   469 zdvd_zmultD            -> dvd_mult_right
   470 zdvd_zmultD2           -> dvd_mult_left
   471 zdvd_zmult_mono        -> mult_dvd_mono
   472 zdvd_0_right           -> dvd_0_right
   473 zdvd_0_left            -> dvd_0_left_iff
   474 zdvd_1_left            -> one_dvd
   475 zminus_dvd_iff         -> minus_dvd_iff
   476 
   477 * HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   478 zlcm (for int); carried together from various gcd/lcm developements in
   479 the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
   480 corresponding theorems renamed accordingly.  INCOMPATIBILITY.  To
   481 recover tupled syntax, use syntax declarations like:
   482 
   483     hide (open) const gcd
   484     abbreviation gcd where
   485       "gcd == (%(a, b). GCD.gcd a b)"
   486     notation (output)
   487       GCD.gcd ("gcd '(_, _')")
   488 
   489 (analogously for lcm, zgcd, zlcm).
   490 
   491 * HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   492 
   493 * The real numbers offer decimal input syntax: 12.34 is translated into
   494   1234/10^2. This translation is not reversed upon output.
   495 
   496 * New ML antiquotation @{code}: takes constant as argument, generates
   497 corresponding code in background and inserts name of the corresponding
   498 resulting ML value/function/datatype constructor binding in place.
   499 All occurrences of @{code} with a single ML block are generated
   500 simultaneously.  Provides a generic and safe interface for
   501 instrumentalizing code generation.  See HOL/Decision_Procs/Ferrack for
   502 a more ambitious application.  In future you ought refrain from ad-hoc
   503 compiling generated SML code on the ML toplevel.  Note that (for technical
   504 reasons) @{code} cannot refer to constants for which user-defined
   505 serializations are set.  Refer to the corresponding ML counterpart
   506 directly in that cases.
   507 
   508 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   509 Complex_Main.thy remain as they are.
   510 
   511 * New image HOL-Plain provides a minimal HOL with the most important
   512 tools available (inductive, datatype, primrec, ...).  By convention
   513 the corresponding theory Plain should be ancestor of every further
   514 (library) theory.  Some library theories now have ancestor Plain
   515 (instead of Main), thus theory Main occasionally has to be imported
   516 explicitly.
   517 
   518 * The metis method now fails in the usual manner, rather than raising
   519 an exception, if it determines that it cannot prove the theorem.
   520 
   521 * The metis method no longer fails because the theorem is too trivial
   522 (contains the empty clause).
   523 
   524 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   525 as the structured Isar versions "cases" and "induct", cf. the
   526 corresponding "cases" and "induct" attributes.  Mutual induction rules
   527 are now presented as a list of individual projections
   528 (e.g. foo_bar.inducts for types foo and bar); the old format with
   529 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   530 rare situations a different rule is selected --- notably nested tuple
   531 elimination instead of former prod.exhaust: use explicit (case_tac t
   532 rule: prod.exhaust) here.
   533 
   534 * Attributes "cases", "induct", "coinduct" support "del" option.
   535 
   536 * Removed fact "case_split_thm", which duplicates "case_split".
   537 
   538 * Command 'rep_datatype': instead of theorem names the command now
   539 takes a list of terms denoting the constructors of the type to be
   540 represented as datatype.  The characteristic theorems have to be
   541 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   542 have disappeared in favour of existing ones:
   543 
   544     unit_induct                 ~> unit.induct
   545     prod_induct                 ~> prod.induct
   546     sum_induct                  ~> sum.induct
   547     Suc_Suc_eq                  ~> nat.inject
   548     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   549 
   550 * The option datatype has been moved to a new theory HOL/Option.thy.
   551 Renamed option_map to Option.map, and o2s to Option.set.
   552 
   553 * Library/Nat_Infinity: added addition, numeral syntax and more
   554 instantiations for algebraic structures.  Removed some duplicate
   555 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   556 
   557 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   558 menu.
   559 
   560 * Linear arithmetic now ignores all inequalities when
   561 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   562 
   563 
   564 *** HOL-Algebra ***
   565 
   566 * New locales for orders and lattices where the equivalence relation
   567 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   568 locales use a record structure with field eq for the equivalence.
   569 
   570 * New theory of factorial domains.
   571 
   572 * Units_l_inv and Units_r_inv are now simprules by default.
   573 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   574 and/or r_inv will now also require deletion of these lemmas.
   575 
   576 * Renamed the following theorems.  INCOMPATIBILITY.
   577 UpperD ~> Upper_memD
   578 LowerD ~> Lower_memD
   579 least_carrier ~> least_closed
   580 greatest_carrier ~> greatest_closed
   581 greatest_Lower_above ~> greatest_Lower_below
   582 one_zero ~> carrier_one_zero
   583 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   584 
   585 
   586 *** HOL-NSA ***
   587 
   588 * Created new image HOL-NSA, containing theories of nonstandard
   589 analysis which were previously part of HOL-Complex.  Entry point
   590 Hyperreal.thy remains valid, but theories formerly using
   591 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   592 
   593 
   594 *** ZF ***
   595 
   596 * Proof of Zorn's Lemma for partial orders.
   597 
   598 
   599 *** HOLCF ***
   600 
   601 * Reimplemented the simplification procedure for proving continuity
   602 subgoals.  The new simproc is extensible; users can declare additional
   603 continuity introduction rules with the attribute [cont2cont].
   604 
   605 * The continuity simproc now uses a different introduction rule for
   606 solving continuity subgoals on terms with lambda abstractions.  In
   607 some rare cases the new simproc may fail to solve subgoals that the
   608 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   609 Potential INCOMPATIBILITY.
   610 
   611 * The syntax of the fixrec package has changed.  The specification
   612 syntax now conforms in style to definition, primrec, function, etc.
   613 See HOLCF/ex/Fixrec_ex.thy for examples.  INCOMPATIBILITY.
   614 
   615 
   616 *** ML ***
   617 
   618 * High-level support for concurrent ML programming, see
   619 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   620 particularly convenient to organize independent functional
   621 computations.  The concept of "synchronized variables" provides a
   622 higher-order interface for components with shared state, avoiding the
   623 delicate details of mutexes and condition variables.  [Poly/ML 5.2.1
   624 or later]
   625 
   626 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   627 and Method.setup, as well as commands 'attribute_setup' and
   628 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   629 existing code accordingly, or use plain 'setup' together with old
   630 Method.add_method.
   631 
   632 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   633 to 'a -> thm, while results are always tagged with an authentic oracle
   634 name.  The Isar command 'oracle' is now polymorphic, no argument type
   635 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   636 accordingly.  Note that extra performance may be gained by producing
   637 the cterm carefully, avoiding slow Thm.cterm_of.
   638 
   639 * ML bindings produced via Isar commands are stored within the Isar
   640 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   641 become thread-safe and work with undo as expected (concerning
   642 top-level bindings, not side-effects on global references).
   643 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   644 compiler at runtime; really global bindings need to be given outside a
   645 theory. [Poly/ML 5.2 or later]
   646 
   647 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   648 context. Top-level ML bindings are stored within the proof context in
   649 a purely sequential fashion, disregarding the nested proof structure.
   650 ML bindings introduced by 'ML_prf' are discarded at the end of the
   651 proof.  [Poly/ML 5.2 or later]
   652 
   653 * Generic Toplevel.add_hook interface allows to analyze the result of
   654 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   655 for theorem dependency output of transactions resulting in a new
   656 theory state.
   657 
   658 * More systematic treatment of long names, abstract name bindings, and
   659 name space operations.  Basic operations on qualified names have been
   660 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   661 Long_Name.append.  Old type bstring has been mostly replaced by
   662 abstract type binding (see structure Binding), which supports precise
   663 qualification (by packages and local theory targets), as well as
   664 proper tracking of source positions.  INCOMPATIBILITY, need to wrap
   665 old bstring values into Binding.name, or better pass through abstract
   666 bindings everywhere.  See further src/Pure/General/long_name.ML,
   667 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   668 
   669 * Simplified interface for defining document antiquotations via
   670 ThyOutput.antiquotation, ThyOutput.output, and optionally
   671 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   672 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   673 examples.
   674 
   675 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   676 LocalTheory.note etc.) now refer to the *full* internal name, not the
   677 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   678 
   679 * Rules and tactics that read instantiations (read_instantiate,
   680 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   681 context, which is required for parsing and type-checking.  Moreover,
   682 the variables are specified as plain indexnames, not string encodings
   683 thereof.  INCOMPATIBILITY.
   684 
   685 * Disposed old type and term read functions (Sign.read_def_typ,
   686 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   687 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   688 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   689 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   690 resort for legacy applications.
   691 
   692 * Disposed old declarations, tactics, tactic combinators that refer to
   693 the simpset or claset of an implicit theory (such as Addsimps,
   694 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   695 embedded ML text, or local_simpset_of with a proper context passed as
   696 explicit runtime argument.
   697 
   698 * Antiquotations: block-structured compilation context indicated by
   699 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   700 
   701   @{let ?pat = term}                      - term abbreviation (HO matching)
   702   @{note name = fact}                     - fact abbreviation
   703   @{thm fact}                             - singleton fact (with attributes)
   704   @{thms fact}                            - general fact (with attributes)
   705   @{lemma prop by method}                 - singleton goal
   706   @{lemma prop by meth1 meth2}            - singleton goal
   707   @{lemma prop1 ... propN by method}      - general goal
   708   @{lemma prop1 ... propN by meth1 meth2} - general goal
   709   @{lemma (open) ...}                     - open derivation
   710 
   711 
   712 *** System ***
   713 
   714 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   715 Poly/ML 5.2.1 or later.
   716 
   717 * The Isabelle "emacs" tool provides a specific interface to invoke
   718 Proof General / Emacs, with more explicit failure if that is not
   719 installed (the old isabelle-interface script silently falls back on
   720 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   721 installation location of the Proof General distribution.
   722 
   723 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   724 the Isabelle process into a JVM/Scala application.  See
   725 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   726 process wrapper has been discontinued.)
   727 
   728 * Status messages (with exact source position information) are
   729 emitted, if proper markup print mode is enabled.  This allows
   730 user-interface components to provide detailed feedback on internal
   731 prover operations.
   732 
   733 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   734 
   735 
   736 
   737 New in Isabelle2008 (June 2008)
   738 -------------------------------
   739 
   740 *** General ***
   741 
   742 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   743 and updated, with formally checked references as hyperlinks.
   744 
   745 * Theory loader: use_thy (and similar operations) no longer set the
   746 implicit ML context, which was occasionally hard to predict and in
   747 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   748 provides a proper context already.
   749 
   750 * Theory loader: old-style ML proof scripts being *attached* to a thy
   751 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   752 'use' within a theory file will do the job.
   753 
   754 * Name space merge now observes canonical order, i.e. the second space
   755 is inserted into the first one, while existing entries in the first
   756 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   757 swap theory imports.
   758 
   759 * Syntax: symbol \<chi> is now considered a letter.  Potential
   760 INCOMPATIBILITY in identifier syntax etc.
   761 
   762 * Outer syntax: string tokens no longer admit escaped white space,
   763 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   764 white space without escapes.
   765 
   766 * Outer syntax: string tokens may contain arbitrary character codes
   767 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   768 "foo_bar".
   769 
   770 
   771 *** Pure ***
   772 
   773 * Context-dependent token translations.  Default setup reverts locally
   774 fixed variables, and adds hilite markup for undeclared frees.
   775 
   776 * Unused theorems can be found using the new command 'unused_thms'.
   777 There are three ways of invoking it:
   778 
   779 (1) unused_thms
   780      Only finds unused theorems in the current theory.
   781 
   782 (2) unused_thms thy_1 ... thy_n -
   783      Finds unused theorems in the current theory and all of its ancestors,
   784      excluding the theories thy_1 ... thy_n and all of their ancestors.
   785 
   786 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   787      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   788      their ancestors, excluding the theories thy_1 ... thy_n and all of
   789      their ancestors.
   790 
   791 In order to increase the readability of the list produced by
   792 unused_thms, theorems that have been created by a particular instance
   793 of a theory command such as 'inductive' or 'function' are considered
   794 to belong to the same "group", meaning that if at least one theorem in
   795 this group is used, the other theorems in the same group are no longer
   796 reported as unused.  Moreover, if all theorems in the group are
   797 unused, only one theorem in the group is displayed.
   798 
   799 Note that proof objects have to be switched on in order for
   800 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   801 usually the case when using Proof General with the default settings).
   802 
   803 * Authentic naming of facts disallows ad-hoc overwriting of previous
   804 theorems within the same name space.  INCOMPATIBILITY, need to remove
   805 duplicate fact bindings, or even accidental fact duplications.  Note
   806 that tools may maintain dynamically scoped facts systematically, using
   807 PureThy.add_thms_dynamic.
   808 
   809 * Command 'hide' now allows to hide from "fact" name space as well.
   810 
   811 * Eliminated destructive theorem database, simpset, claset, and
   812 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   813 update of theories within ML code.
   814 
   815 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   816 INCOMPATIBILITY, object-logics depending on former Pure require
   817 additional setup PureThy.old_appl_syntax_setup; object-logics
   818 depending on former CPure need to refer to Pure.
   819 
   820 * Commands 'use' and 'ML' are now purely functional, operating on
   821 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   822 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   823 INCOMPATIBILITY.
   824 
   825 * Command 'setup': discontinued implicit version with ML reference.
   826 
   827 * Instantiation target allows for simultaneous specification of class
   828 instance operations together with an instantiation proof.
   829 Type-checking phase allows to refer to class operations uniformly.
   830 See src/HOL/Complex/Complex.thy for an Isar example and
   831 src/HOL/Library/Eval.thy for an ML example.
   832 
   833 * Indexing of literal facts: be more serious about including only
   834 facts from the visible specification/proof context, but not the
   835 background context (locale etc.).  Affects `prop` notation and method
   836 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   837 situations.
   838 
   839 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   840 "(open)" option, which used to expose internal bound variables to the
   841 proof text.
   842 
   843 * Isar statements: removed obsolete case "rule_context".
   844 INCOMPATIBILITY, better use explicit fixes/assumes.
   845 
   846 * Locale proofs: default proof step now includes 'unfold_locales';
   847 hence 'proof' without argument may be used to unfold locale
   848 predicates.
   849 
   850 
   851 *** Document preparation ***
   852 
   853 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   854 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   855 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   856 spot); renamed link color from "darkblue" to "linkcolor" (default
   857 value unchanged, can be redefined via \definecolor); no longer sets
   858 "a4paper" option (unnecessary or even intrusive).
   859 
   860 * Antiquotation @{lemma A method} proves proposition A by the given
   861 method (either a method name or a method name plus (optional) method
   862 arguments in parentheses) and prints A just like @{prop A}.
   863 
   864 
   865 *** HOL ***
   866 
   867 * New primrec package.  Specification syntax conforms in style to
   868 definition/function/....  No separate induction rule is provided.  The
   869 "primrec" command distinguishes old-style and new-style specifications
   870 by syntax.  The former primrec package is now named OldPrimrecPackage.
   871 When adjusting theories, beware: constants stemming from new-style
   872 primrec specifications have authentic syntax.
   873 
   874 * Metis prover is now an order of magnitude faster, and also works
   875 with multithreading.
   876 
   877 * Metis: the maximum number of clauses that can be produced from a
   878 theorem is now given by the attribute max_clauses.  Theorems that
   879 exceed this number are ignored, with a warning printed.
   880 
   881 * Sledgehammer no longer produces structured proofs by default. To
   882 enable, declare [[sledgehammer_full = true]].  Attributes
   883 reconstruction_modulus, reconstruction_sorts renamed
   884 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   885 
   886 * Method "induct_scheme" derives user-specified induction rules
   887 from well-founded induction and completeness of patterns. This factors
   888 out some operations that are done internally by the function package
   889 and makes them available separately.  See
   890 src/HOL/ex/Induction_Scheme.thy for examples.
   891 
   892 * More flexible generation of measure functions for termination
   893 proofs: Measure functions can be declared by proving a rule of the
   894 form "is_measure f" and giving it the [measure_function] attribute.
   895 The "is_measure" predicate is logically meaningless (always true), and
   896 just guides the heuristic.  To find suitable measure functions, the
   897 termination prover sets up the goal "is_measure ?f" of the appropriate
   898 type and generates all solutions by prolog-style backwards proof using
   899 the declared rules.
   900 
   901 This setup also deals with rules like 
   902 
   903   "is_measure f ==> is_measure (list_size f)"
   904 
   905 which accommodates nested datatypes that recurse through lists.
   906 Similar rules are predeclared for products and option types.
   907 
   908 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   909 
   910   INCOMPATIBILITIES:
   911 
   912   - Definitions of overloaded constants on sets have to be replaced by
   913     definitions on => and bool.
   914 
   915   - Some definitions of overloaded operators on sets can now be proved
   916     using the definitions of the operators on => and bool.  Therefore,
   917     the following theorems have been renamed:
   918 
   919       subset_def   -> subset_eq
   920       psubset_def  -> psubset_eq
   921       set_diff_def -> set_diff_eq
   922       Compl_def    -> Compl_eq
   923       Sup_set_def  -> Sup_set_eq
   924       Inf_set_def  -> Inf_set_eq
   925       sup_set_def  -> sup_set_eq
   926       inf_set_def  -> inf_set_eq
   927 
   928   - Due to the incompleteness of the HO unification algorithm, some
   929     rules such as subst may require manual instantiation, if some of
   930     the unknowns in the rule is a set.
   931 
   932   - Higher order unification and forward proofs:
   933     The proof pattern
   934 
   935       have "P (S::'a set)" <...>
   936       then have "EX S. P S" ..
   937 
   938     no longer works (due to the incompleteness of the HO unification
   939     algorithm) and must be replaced by the pattern
   940 
   941       have "EX S. P S"
   942       proof
   943         show "P S" <...>
   944       qed
   945 
   946   - Calculational reasoning with subst (or similar rules):
   947     The proof pattern
   948 
   949       have "P (S::'a set)" <...>
   950       also have "S = T" <...>
   951       finally have "P T" .
   952 
   953     no longer works (for similar reasons as the previous example) and
   954     must be replaced by something like
   955 
   956       have "P (S::'a set)" <...>
   957       moreover have "S = T" <...>
   958       ultimately have "P T" by simp
   959 
   960   - Tactics or packages written in ML code:
   961     Code performing pattern matching on types via
   962 
   963       Type ("set", [T]) => ...
   964 
   965     must be rewritten. Moreover, functions like strip_type or
   966     binder_types no longer return the right value when applied to a
   967     type of the form
   968 
   969       T1 => ... => Tn => U => bool
   970 
   971     rather than
   972 
   973       T1 => ... => Tn => U set
   974 
   975 * Merged theories Wellfounded_Recursion, Accessible_Part and
   976 Wellfounded_Relations to theory Wellfounded.
   977 
   978 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   979 
   980 * Class finite no longer treats UNIV as class parameter.  Use class
   981 enum from theory Library/Enum instead to achieve a similar effect.
   982 INCOMPATIBILITY.
   983 
   984 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   985 and "Cons".  INCOMPATIBILITY.
   986 
   987 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   988 Potential INCOMPATIBILITY.
   989 
   990 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   991 injective_fst_snd removed, use split_eta and prod_eqI instead.
   992 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   993 
   994 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   995 the same name in theory Orderings:
   996 
   997   less_trans
   998   less_linear
   999   le_imp_less_or_eq
  1000   le_less_trans
  1001   less_le_trans
  1002   less_not_sym
  1003   less_asym
  1004 
  1005 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1006 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1007 and different variable names.
  1008 
  1009 * Library/Option_ord.thy: Canonical order on option type.
  1010 
  1011 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1012 finite maps.
  1013 
  1014 * Library/Countable.thy: Type class for countable types.
  1015 
  1016 * Theory Int: The representation of numerals has changed.  The infix
  1017 operator BIT and the bit datatype with constructors B0 and B1 have
  1018 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1019 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1020 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1021 accordingly.
  1022 
  1023 * Theory Nat: definition of <= and < on natural numbers no longer
  1024 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1025 le_def and less_def have disappeared.  Consider lemmas not_less
  1026 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1027 
  1028 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1029 (whose purpose mainly is for various fold_set functionals) have been
  1030 abandoned in favor of the existing algebraic classes
  1031 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1032 lower_semilattice (resp. upper_semilattice) and linorder.
  1033 INCOMPATIBILITY.
  1034 
  1035 * Theory Transitive_Closure: induct and cases rules now declare proper
  1036 case_names ("base" and "step").  INCOMPATIBILITY.
  1037 
  1038 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1039 lattices.  The form set-specific version is available as
  1040 Inductive.lfp_ordinal_induct_set.
  1041 
  1042 * Renamed theorems "power.simps" to "power_int.simps".
  1043 INCOMPATIBILITY.
  1044 
  1045 * Class semiring_div provides basic abstract properties of semirings
  1046 with division and modulo operations.  Subsumes former class dvd_mod.
  1047 
  1048 * Merged theories IntDef, Numeral and IntArith into unified theory
  1049 Int.  INCOMPATIBILITY.
  1050 
  1051 * Theory Library/Code_Index: type "index" now represents natural
  1052 numbers rather than integers.  INCOMPATIBILITY.
  1053 
  1054 * New class "uminus" with operation "uminus" (split of from class
  1055 "minus" which now only has operation "minus", binary).
  1056 INCOMPATIBILITY.
  1057 
  1058 * Constants "card", "internal_split", "option_map" now with authentic
  1059 syntax.  INCOMPATIBILITY.
  1060 
  1061 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1062 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1063 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1064 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1065 Sup_set_def, le_def, less_def, option_map_def now with object
  1066 equality.  INCOMPATIBILITY.
  1067 
  1068 * Records. Removed K_record, and replaced it by pure lambda term
  1069 %x. c. The simplifier setup is now more robust against eta expansion.
  1070 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1071 
  1072 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1073 
  1074 * Library/ListVector: new theory of arithmetic vector operations.
  1075 
  1076 * Library/Order_Relation: new theory of various orderings as sets of
  1077 pairs.  Defines preorders, partial orders, linear orders and
  1078 well-orders on sets and on types.
  1079 
  1080 
  1081 *** ZF ***
  1082 
  1083 * Renamed some theories to allow to loading both ZF and HOL in the
  1084 same session:
  1085 
  1086   Datatype  -> Datatype_ZF
  1087   Inductive -> Inductive_ZF
  1088   Int       -> Int_ZF
  1089   IntDiv    -> IntDiv_ZF
  1090   Nat       -> Nat_ZF
  1091   List      -> List_ZF
  1092   Main      -> Main_ZF
  1093 
  1094 INCOMPATIBILITY: ZF theories that import individual theories below
  1095 Main might need to be adapted.  Regular theory Main is still
  1096 available, as trivial extension of Main_ZF.
  1097 
  1098 
  1099 *** ML ***
  1100 
  1101 * ML within Isar: antiquotation @{const name} or @{const
  1102 name(typargs)} produces statically-checked Const term.
  1103 
  1104 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1105 (of the same name).  Removed obsolete print command.
  1106 
  1107 * Removed obsolete "use_legacy_bindings" function.
  1108 
  1109 * The ``print mode'' is now a thread-local value derived from a global
  1110 template (the former print_mode reference), thus access becomes
  1111 non-critical.  The global print_mode reference is for session
  1112 management only; user-code should use print_mode_value,
  1113 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1114 
  1115 * Functions system/system_out provide a robust way to invoke external
  1116 shell commands, with propagation of interrupts (requires Poly/ML
  1117 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1118 
  1119 
  1120 *** System ***
  1121 
  1122 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1123 in accordance with Proof General 3.7, which prefers GNU emacs.
  1124 
  1125 * isatool tty runs Isabelle process with plain tty interaction;
  1126 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1127 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1128 
  1129 * isatool browser now works with Cygwin as well, using general
  1130 "javapath" function defined in Isabelle process environment.
  1131 
  1132 * YXML notation provides a simple and efficient alternative to
  1133 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1134 isatool yxml as described in the Isabelle system manual.
  1135 
  1136 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1137 provides general wrapper for managing an Isabelle process in a robust
  1138 fashion, with ``cooked'' output from stdin/stderr.
  1139 
  1140 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1141 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1142 
  1143 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1144 way of changing the user's settings is via
  1145 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1146 script.
  1147 
  1148 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1149 cores of the underlying machine, which is a good starting point for
  1150 optimal performance tuning.  The corresponding usedir option -M allows
  1151 "max" as an alias for "0".  WARNING: does not work on certain versions
  1152 of Mac OS (with Poly/ML 5.1).
  1153 
  1154 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1155 adverse effect of Isabelle flooding interactive front-ends (notably
  1156 ProofGeneral / XEmacs).
  1157 
  1158 
  1159 
  1160 New in Isabelle2007 (November 2007)
  1161 -----------------------------------
  1162 
  1163 *** General ***
  1164 
  1165 * More uniform information about legacy features, notably a
  1166 warning/error of "Legacy feature: ...", depending on the state of the
  1167 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1168 legacy features will disappear eventually.
  1169 
  1170 * Theory syntax: the header format ``theory A = B + C:'' has been
  1171 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1172 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1173 
  1174 * Theory syntax: the old non-Isar theory file format has been
  1175 discontinued altogether.  Note that ML proof scripts may still be used
  1176 with Isar theories; migration is usually quite simple with the ML
  1177 function use_legacy_bindings.  INCOMPATIBILITY.
  1178 
  1179 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1180 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1181 quotes.
  1182 
  1183 * Theory loader: be more serious about observing the static theory
  1184 header specifications (including optional directories), but not the
  1185 accidental file locations of previously successful loads.  The strict
  1186 update policy of former update_thy is now already performed by
  1187 use_thy, so the former has been removed; use_thys updates several
  1188 theories simultaneously, just as 'imports' within a theory header
  1189 specification, but without merging the results.  Potential
  1190 INCOMPATIBILITY: may need to refine theory headers and commands
  1191 ROOT.ML which depend on load order.
  1192 
  1193 * Theory loader: optional support for content-based file
  1194 identification, instead of the traditional scheme of full physical
  1195 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1196 (cf. the system manual).  The new scheme allows to work with
  1197 non-finished theories in persistent session images, such that source
  1198 files may be moved later on without requiring reloads.
  1199 
  1200 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1201 file (with the same base name as the theory) are considered a legacy
  1202 feature, which will disappear eventually. Even now, the theory loader
  1203 no longer maintains dependencies on such files.
  1204 
  1205 * Syntax: the scope for resolving ambiguities via type-inference is
  1206 now limited to individual terms, instead of whole simultaneous
  1207 specifications as before. This greatly reduces the complexity of the
  1208 syntax module and improves flexibility by separating parsing and
  1209 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1210 'fixes' etc.) are required in rare situations.
  1211 
  1212 * Syntax: constants introduced by new-style packages ('definition',
  1213 'abbreviation' etc.) are passed through the syntax module in
  1214 ``authentic mode''. This means that associated mixfix annotations
  1215 really stick to such constants, independently of potential name space
  1216 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1217 trees are represented slightly differently, may need to adapt syntax
  1218 translations accordingly. Use CONST marker in 'translations' and
  1219 @{const_syntax} antiquotation in 'parse_translation' etc.
  1220 
  1221 * Legacy goal package: reduced interface to the bare minimum required
  1222 to keep existing proof scripts running.  Most other user-level
  1223 functions are now part of the OldGoals structure, which is *not* open
  1224 by default (consider isatool expandshort before open OldGoals).
  1225 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1226 these tend to cause confusion about the actual goal (!) context being
  1227 used here, which is not necessarily the same as the_context().
  1228 
  1229 * Command 'find_theorems': supports "*" wild-card in "name:"
  1230 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1231 support a specific search form (see ProofGeneral/CHANGES).
  1232 
  1233 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1234 by default, which means that "prems" (and also "fixed variables") are
  1235 suppressed from proof state output.  Note that the ProofGeneral
  1236 settings mechanism allows to change and save options persistently, but
  1237 older versions of Isabelle will fail to start up if a negative prems
  1238 limit is imposed.
  1239 
  1240 * Local theory targets may be specified by non-nested blocks of
  1241 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1242 contain definitions, theorems etc., including any derived mechanism
  1243 that has been implemented on top of these primitives.  This concept
  1244 generalizes the existing ``theorem (in ...)'' towards more versatility
  1245 and scalability.
  1246 
  1247 * Proof General interface: proper undo of final 'end' command;
  1248 discontinued Isabelle/classic mode (ML proof scripts).
  1249 
  1250 
  1251 *** Document preparation ***
  1252 
  1253 * Added antiquotation @{theory name} which prints the given name,
  1254 after checking that it refers to a valid ancestor theory in the
  1255 current context.
  1256 
  1257 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1258 check the given source text as ML type/structure, printing verbatim.
  1259 
  1260 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1261 "c args == rhs" given in the current context.  (Any number of
  1262 arguments may be given on the LHS.)
  1263 
  1264 
  1265 *** Pure ***
  1266 
  1267 * The 'class' package offers a combination of axclass and locale to
  1268 achieve Haskell-like type classes in Isabelle.  Definitions and
  1269 theorems within a class context produce both relative results (with
  1270 implicit parameters according to the locale context), and polymorphic
  1271 constants with qualified polymorphism (according to the class
  1272 context).  Within the body context of a 'class' target, a separate
  1273 syntax layer ("user space type system") takes care of converting
  1274 between global polymorphic consts and internal locale representation.
  1275 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1276 "isatool doc classes" provides a tutorial.
  1277 
  1278 * Generic code generator framework allows to generate executable
  1279 code for ML and Haskell (including Isabelle classes).  A short usage
  1280 sketch:
  1281 
  1282     internal compilation:
  1283         export_code <list of constants (term syntax)> in SML
  1284     writing SML code to a file:
  1285         export_code <list of constants (term syntax)> in SML <filename>
  1286     writing OCaml code to a file:
  1287         export_code <list of constants (term syntax)> in OCaml <filename>
  1288     writing Haskell code to a bunch of files:
  1289         export_code <list of constants (term syntax)> in Haskell <filename>
  1290 
  1291     evaluating closed propositions to True/False using code generation:
  1292         method ``eval''
  1293 
  1294 Reasonable default setup of framework in HOL.
  1295 
  1296 Theorem attributs for selecting and transforming function equations theorems:
  1297 
  1298     [code fun]:        select a theorem as function equation for a specific constant
  1299     [code fun del]:    deselect a theorem as function equation for a specific constant
  1300     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1301     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1302 
  1303 User-defined serializations (target in {SML, OCaml, Haskell}):
  1304 
  1305     code_const <and-list of constants (term syntax)>
  1306       {(target) <and-list of const target syntax>}+
  1307 
  1308     code_type <and-list of type constructors>
  1309       {(target) <and-list of type target syntax>}+
  1310 
  1311     code_instance <and-list of instances>
  1312       {(target)}+
  1313         where instance ::= <type constructor> :: <class>
  1314 
  1315     code_class <and_list of classes>
  1316       {(target) <and-list of class target syntax>}+
  1317         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1318 
  1319 code_instance and code_class only are effective to target Haskell.
  1320 
  1321 For example usage see src/HOL/ex/Codegenerator.thy and
  1322 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1323 generation from Isabelle/HOL theories is available via "isatool doc
  1324 codegen".
  1325 
  1326 * Code generator: consts in 'consts_code' Isar commands are now
  1327 referred to by usual term syntax (including optional type
  1328 annotations).
  1329 
  1330 * Command 'no_translations' removes translation rules from theory
  1331 syntax.
  1332 
  1333 * Overloaded definitions are now actually checked for acyclic
  1334 dependencies.  The overloading scheme is slightly more general than
  1335 that of Haskell98, although Isabelle does not demand an exact
  1336 correspondence to type class and instance declarations.
  1337 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1338 exotic versions of overloading -- at the discretion of the user!
  1339 
  1340 Polymorphic constants are represented via type arguments, i.e. the
  1341 instantiation that matches an instance against the most general
  1342 declaration given in the signature.  For example, with the declaration
  1343 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1344 as c(nat).  Overloading is essentially simultaneous structural
  1345 recursion over such type arguments.  Incomplete specification patterns
  1346 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1347 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1348 Command 'print_theory' outputs the normalized system of recursive
  1349 equations, see section "definitions".
  1350 
  1351 * Configuration options are maintained within the theory or proof
  1352 context (with name and type bool/int/string), providing a very simple
  1353 interface to a poor-man's version of general context data.  Tools may
  1354 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1355 these values using Config.get etc.  Users may change options via an
  1356 associated attribute of the same name.  This form of context
  1357 declaration works particularly well with commands 'declare' or
  1358 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1359 very easy to avoid global references, which would not observe Isar
  1360 toplevel undo/redo and fail to work with multithreading.
  1361 
  1362 Various global ML references of Pure and HOL have been turned into
  1363 configuration options:
  1364 
  1365   Unify.search_bound		unify_search_bound
  1366   Unify.trace_bound		unify_trace_bound
  1367   Unify.trace_simp		unify_trace_simp
  1368   Unify.trace_types		unify_trace_types
  1369   Simplifier.simp_depth_limit	simp_depth_limit
  1370   Blast.depth_limit		blast_depth_limit
  1371   DatatypeProp.dtK		datatype_distinctness_limit
  1372   fast_arith_neq_limit  	fast_arith_neq_limit
  1373   fast_arith_split_limit	fast_arith_split_limit
  1374 
  1375 * Named collections of theorems may be easily installed as context
  1376 data using the functor NamedThmsFun (see also
  1377 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1378 attributes; there is also a toplevel print command.  This facility is
  1379 just a common case of general context data, which is the preferred way
  1380 for anything more complex than just a list of facts in canonical
  1381 order.
  1382 
  1383 * Isar: command 'declaration' augments a local theory by generic
  1384 declaration functions written in ML.  This enables arbitrary content
  1385 being added to the context, depending on a morphism that tells the
  1386 difference of the original declaration context wrt. the application
  1387 context encountered later on.
  1388 
  1389 * Isar: proper interfaces for simplification procedures.  Command
  1390 'simproc_setup' declares named simprocs (with match patterns, and body
  1391 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1392 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1393 
  1394 * Isar: an extra pair of brackets around attribute declarations
  1395 abbreviates a theorem reference involving an internal dummy fact,
  1396 which will be ignored later --- only the effect of the attribute on
  1397 the background context will persist.  This form of in-place
  1398 declarations is particularly useful with commands like 'declare' and
  1399 'using', for example ``have A using [[simproc a]] by simp''.
  1400 
  1401 * Isar: method "assumption" (and implicit closing of subproofs) now
  1402 takes simple non-atomic goal assumptions into account: after applying
  1403 an assumption as a rule the resulting subgoals are solved by atomic
  1404 assumption steps.  This is particularly useful to finish 'obtain'
  1405 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1406 without referring to the original premise "!!x. P x ==> thesis" in the
  1407 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1408 more permissive.
  1409 
  1410 * Isar: implicit use of prems from the Isar proof context is
  1411 considered a legacy feature.  Common applications like ``have A .''
  1412 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1413 referencing facts explicitly here improves readability and
  1414 maintainability of proof texts.
  1415 
  1416 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1417 the obtained context from the course of reasoning!  For example:
  1418 
  1419   assume "EX x y. A x & B y"   -- "any previous fact"
  1420   then guess x and y by clarify
  1421 
  1422 This technique is potentially adventurous, depending on the facts and
  1423 proof tools being involved here.
  1424 
  1425 * Isar: known facts from the proof context may be specified as literal
  1426 propositions, using ASCII back-quote syntax.  This works wherever
  1427 named facts used to be allowed so far, in proof commands, proof
  1428 methods, attributes etc.  Literal facts are retrieved from the context
  1429 according to unification of type and term parameters.  For example,
  1430 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1431 theorems in the current context, then these are valid literal facts:
  1432 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1433 
  1434 There is also a proof method "fact" which does the same composition
  1435 for explicit goal states, e.g. the following proof texts coincide with
  1436 certain special cases of literal facts:
  1437 
  1438   have "A" by fact                 ==  note `A`
  1439   have "A ==> B" by fact           ==  note `A ==> B`
  1440   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1441   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1442 
  1443 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1444 outer syntax.  Thus symbolic identifiers may be used without
  1445 additional white space in declarations like this: ``assume *: A''.
  1446 
  1447 * Isar: 'print_facts' prints all local facts of the current context,
  1448 both named and unnamed ones.
  1449 
  1450 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1451 
  1452   def x == "t" and y == "u"
  1453 
  1454 * Isar: added command 'unfolding', which is structurally similar to
  1455 'using', but affects both the goal state and facts by unfolding given
  1456 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1457 'unfolded' attribute may be replaced by first-class proof text.
  1458 
  1459 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1460 and command 'unfolding' now all support object-level equalities
  1461 (potentially conditional).  The underlying notion of rewrite rule is
  1462 analogous to the 'rule_format' attribute, but *not* that of the
  1463 Simplifier (which is usually more generous).
  1464 
  1465 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1466 premises of a theorem by n. Useful in conjunction with drule.
  1467 
  1468 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1469 method expression within a sandbox consisting of the first N
  1470 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1471 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1472 simplifies all new goals that emerge from applying rule foo to the
  1473 originally first one.
  1474 
  1475 * Isar: schematic goals are no longer restricted to higher-order
  1476 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1477 expected.
  1478 
  1479 * Isar: the conclusion of a long theorem statement is now either
  1480 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1481 (essentially a disjunction of cases with local parameters and
  1482 assumptions).  The latter allows to express general elimination rules
  1483 adequately; in this notation common elimination rules look like this:
  1484 
  1485   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1486     assumes "EX x. P x"
  1487     obtains x where "P x"
  1488 
  1489   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1490     assumes "A & B"
  1491     obtains A and B
  1492 
  1493   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1494     assumes "A | B"
  1495     obtains
  1496       A
  1497     | B
  1498 
  1499 The subsequent classical rules even refer to the formal "thesis"
  1500 explicitly:
  1501 
  1502   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1503     obtains "~ thesis"
  1504 
  1505   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1506     obtains "thesis ==> something"
  1507 
  1508 The actual proof of an 'obtains' statement is analogous to that of the
  1509 Isar proof element 'obtain', only that there may be several cases.
  1510 Optional case names may be specified in parentheses; these will be
  1511 available both in the present proof and as annotations in the
  1512 resulting rule, for later use with the 'cases' method (cf. attribute
  1513 case_names).
  1514 
  1515 * Isar: the assumptions of a long theorem statement are available as
  1516 "assms" fact in the proof context.  This is more appropriate than the
  1517 (historical) "prems", which refers to all assumptions of the current
  1518 context, including those from the target locale, proof body etc.
  1519 
  1520 * Isar: 'print_statement' prints theorems from the current theory or
  1521 proof context in long statement form, according to the syntax of a
  1522 top-level lemma.
  1523 
  1524 * Isar: 'obtain' takes an optional case name for the local context
  1525 introduction rule (default "that").
  1526 
  1527 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1528 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1529 to occur.
  1530 
  1531 * Pure: syntax "CONST name" produces a fully internalized constant
  1532 according to the current context.  This is particularly useful for
  1533 syntax translations that should refer to internal constant
  1534 representations independently of name spaces.
  1535 
  1536 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1537 instead of "FOO ". This allows multiple binder declarations to coexist
  1538 in the same context.  INCOMPATIBILITY.
  1539 
  1540 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1541 primitive that also works in a locale context (both for constants and
  1542 fixed variables). Type declaration and internal syntactic representation
  1543 of given constants retrieved from the context. Likewise, the
  1544 'no_notation' command allows to remove given syntax annotations from the
  1545 current context.
  1546 
  1547 * Isar/locales: new derived specification elements 'axiomatization',
  1548 'definition', 'abbreviation', which support type-inference, admit
  1549 object-level specifications (equality, equivalence).  See also the
  1550 isar-ref manual.  Examples:
  1551 
  1552   axiomatization
  1553     eq  (infix "===" 50) where
  1554     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1555 
  1556   definition "f x y = x + y + 1"
  1557   definition g where "g x = f x x"
  1558 
  1559   abbreviation
  1560     neq  (infix "=!=" 50) where
  1561     "x =!= y == ~ (x === y)"
  1562 
  1563 These specifications may be also used in a locale context.  Then the
  1564 constants being introduced depend on certain fixed parameters, and the
  1565 constant name is qualified by the locale base name.  An internal
  1566 abbreviation takes care for convenient input and output, making the
  1567 parameters implicit and using the original short name.  See also
  1568 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1569 entities from a monomorphic theory.
  1570 
  1571 Presently, abbreviations are only available 'in' a target locale, but
  1572 not inherited by general import expressions.  Also note that
  1573 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1574 'translations' in common applications.  The "no_abbrevs" print mode
  1575 prevents folding of abbreviations in term output.
  1576 
  1577 Concrete syntax is attached to specified constants in internal form,
  1578 independently of name spaces.  The parse tree representation is
  1579 slightly different -- use 'notation' instead of raw 'syntax', and
  1580 'translations' with explicit "CONST" markup to accommodate this.
  1581 
  1582 * Pure/Isar: unified syntax for new-style specification mechanisms
  1583 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1584 full type inference and dummy patterns ("_").  For example:
  1585 
  1586   definition "K x _ = x"
  1587 
  1588   inductive conj for A B
  1589   where "A ==> B ==> conj A B"
  1590 
  1591 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1592 the current context.  Print mode "no_abbrevs" prevents inversion of
  1593 abbreviations on output.
  1594 
  1595 * Isar/locales: improved parameter handling: use of locales "var" and
  1596 "struct" no longer necessary; - parameter renamings are no longer
  1597 required to be injective.  For example, this allows to define
  1598 endomorphisms as locale endom = homom mult mult h.
  1599 
  1600 * Isar/locales: changed the way locales with predicates are defined.
  1601 Instead of accumulating the specification, the imported expression is
  1602 now an interpretation.  INCOMPATIBILITY: different normal form of
  1603 locale expressions.  In particular, in interpretations of locales with
  1604 predicates, goals repesenting already interpreted fragments are not
  1605 removed automatically.  Use methods `intro_locales' and
  1606 `unfold_locales'; see below.
  1607 
  1608 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1609 provide backward reasoning on locales predicates.  The methods are
  1610 aware of interpretations and discharge corresponding goals.
  1611 `intro_locales' is less aggressive then `unfold_locales' and does not
  1612 unfold predicates to assumptions.
  1613 
  1614 * Isar/locales: the order in which locale fragments are accumulated
  1615 has changed.  This enables to override declarations from fragments due
  1616 to interpretations -- for example, unwanted simp rules.
  1617 
  1618 * Isar/locales: interpretation in theories and proof contexts has been
  1619 extended.  One may now specify (and prove) equations, which are
  1620 unfolded in interpreted theorems.  This is useful for replacing
  1621 defined concepts (constants depending on locale parameters) by
  1622 concepts already existing in the target context.  Example:
  1623 
  1624   interpretation partial_order ["op <= :: [int, int] => bool"]
  1625     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1626 
  1627 Typically, the constant `partial_order.less' is created by a
  1628 definition specification element in the context of locale
  1629 partial_order.
  1630 
  1631 * Method "induct": improved internal context management to support
  1632 local fixes and defines on-the-fly. Thus explicit meta-level
  1633 connectives !!  and ==> are rarely required anymore in inductive goals
  1634 (using object-logic connectives for this purpose has been long
  1635 obsolete anyway). Common proof patterns are explained in
  1636 src/HOL/Induct/Common_Patterns.thy, see also
  1637 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1638 examples.
  1639 
  1640 * Method "induct": improved handling of simultaneous goals. Instead of
  1641 introducing object-level conjunction, the statement is now split into
  1642 several conclusions, while the corresponding symbolic cases are nested
  1643 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1644 see src/HOL/Induct/Common_Patterns.thy, for example.
  1645 
  1646 * Method "induct": mutual induction rules are now specified as a list
  1647 of rule sharing the same induction cases. HOL packages usually provide
  1648 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1649 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1650 mutual induction rules differently, i.e. like this:
  1651 
  1652   (induct rule: foo_bar.inducts)
  1653   (induct set: foo bar)
  1654   (induct pred: foo bar)
  1655   (induct type: foo bar)
  1656 
  1657 The ML function ProjectRule.projections turns old-style rules into the
  1658 new format.
  1659 
  1660 * Method "coinduct": dual of induction, see
  1661 src/HOL/Library/Coinductive_List.thy for various examples.
  1662 
  1663 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1664 considered a legacy feature.
  1665 
  1666 * Attribute "symmetric" produces result with standardized schematic
  1667 variables (index 0).  Potential INCOMPATIBILITY.
  1668 
  1669 * Simplifier: by default the simplifier trace only shows top level
  1670 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1671 default. Thus there is less danger of being flooded by the trace. The
  1672 trace indicates where parts have been suppressed.
  1673   
  1674 * Provers/classical: removed obsolete classical version of elim_format
  1675 attribute; classical elim/dest rules are now treated uniformly when
  1676 manipulating the claset.
  1677 
  1678 * Provers/classical: stricter checks to ensure that supplied intro,
  1679 dest and elim rules are well-formed; dest and elim rules must have at
  1680 least one premise.
  1681 
  1682 * Provers/classical: attributes dest/elim/intro take an optional
  1683 weight argument for the rule (just as the Pure versions).  Weights are
  1684 ignored by automated tools, but determine the search order of single
  1685 rule steps.
  1686 
  1687 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1688 where the body does not mention the bound variable.  Note that dummy
  1689 patterns implicitly depend on their context of bounds, which makes
  1690 "{_. _}" match any set comprehension as expected.  Potential
  1691 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1692 constant "_idtdummy" in the binding position.
  1693 
  1694 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1695 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1696 for example "A -> B" => "Pi A (%_. B)".
  1697 
  1698 * Pure: 'class_deps' command visualizes the subclass relation, using
  1699 the graph browser tool.
  1700 
  1701 * Pure: 'print_theory' now suppresses certain internal declarations by
  1702 default; use '!' option for full details.
  1703 
  1704 
  1705 *** HOL ***
  1706 
  1707 * Method "metis" proves goals by applying the Metis general-purpose
  1708 resolution prover (see also http://gilith.com/software/metis/).
  1709 Examples are in the directory MetisExamples.  WARNING: the
  1710 Isabelle/HOL-Metis integration does not yet work properly with
  1711 multi-threading.
  1712   
  1713 * Command 'sledgehammer' invokes external automatic theorem provers as
  1714 background processes.  It generates calls to the "metis" method if
  1715 successful. These can be pasted into the proof.  Users do not have to
  1716 wait for the automatic provers to return.  WARNING: does not really
  1717 work with multi-threading.
  1718 
  1719 * New "auto_quickcheck" feature tests outermost goal statements for
  1720 potential counter-examples.  Controlled by ML references
  1721 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1722 5000 milliseconds).  Fails silently if statements is outside of
  1723 executable fragment, or any other codgenerator problem occurs.
  1724 
  1725 * New constant "undefined" with axiom "undefined x = undefined".
  1726 
  1727 * Added class "HOL.eq", allowing for code generation with polymorphic
  1728 equality.
  1729 
  1730 * Some renaming of class constants due to canonical name prefixing in
  1731 the new 'class' package:
  1732 
  1733     HOL.abs ~> HOL.abs_class.abs
  1734     HOL.divide ~> HOL.divide_class.divide
  1735     0 ~> HOL.zero_class.zero
  1736     1 ~> HOL.one_class.one
  1737     op + ~> HOL.plus_class.plus
  1738     op - ~> HOL.minus_class.minus
  1739     uminus ~> HOL.minus_class.uminus
  1740     op * ~> HOL.times_class.times
  1741     op < ~> HOL.ord_class.less
  1742     op <= > HOL.ord_class.less_eq
  1743     Nat.power ~> Power.power_class.power
  1744     Nat.size ~> Nat.size_class.size
  1745     Numeral.number_of ~> Numeral.number_class.number_of
  1746     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1747     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1748     Orderings.min ~> Orderings.ord_class.min
  1749     Orderings.max ~> Orderings.ord_class.max
  1750     Divides.op div ~> Divides.div_class.div
  1751     Divides.op mod ~> Divides.div_class.mod
  1752     Divides.op dvd ~> Divides.div_class.dvd
  1753 
  1754 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1755 
  1756 a) User-defined constants using any of the names "plus", "minus",
  1757 "times", "less" or "less_eq". The standard syntax translations for
  1758 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1759 names.
  1760 
  1761 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1762 INCOMPATIBILITY: use more specific names.
  1763 
  1764 c) Permutative equations (e.g. "a + b = b + a")
  1765 Since the change of names also changes the order of terms, permutative
  1766 rewrite rules may get applied in a different order. Experience shows
  1767 that this is rarely the case (only two adaptions in the whole Isabelle
  1768 distribution).  INCOMPATIBILITY: rewrite proofs
  1769 
  1770 d) ML code directly refering to constant names
  1771 This in general only affects hand-written proof tactics, simprocs and
  1772 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1773 Consider using @{const_name} antiquotation.
  1774 
  1775 * New class "default" with associated constant "default".
  1776 
  1777 * Function "sgn" is now overloaded and available on int, real, complex
  1778 (and other numeric types), using class "sgn".  Two possible defs of
  1779 sgn are given as equational assumptions in the classes sgn_if and
  1780 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1781 INCOMPATIBILITY.
  1782 
  1783 * Locale "partial_order" now unified with class "order" (cf. theory
  1784 Orderings), added parameter "less".  INCOMPATIBILITY.
  1785 
  1786 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1787 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1788 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1789 
  1790 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1791 changed order of proof goals in instance proofs.
  1792 
  1793 * The transitivity reasoner for partial and linear orders is set up
  1794 for classes "order" and "linorder".  Instances of the reasoner are available
  1795 in all contexts importing or interpreting the corresponding locales.
  1796 Method "order" invokes the reasoner separately; the reasoner
  1797 is also integrated with the Simplifier as a solver.  Diagnostic
  1798 command 'print_orders' shows the available instances of the reasoner
  1799 in the current context.
  1800 
  1801 * Localized monotonicity predicate in theory "Orderings"; integrated
  1802 lemmas max_of_mono and min_of_mono with this predicate.
  1803 INCOMPATIBILITY.
  1804 
  1805 * Formulation of theorem "dense" changed slightly due to integration
  1806 with new class dense_linear_order.
  1807 
  1808 * Uniform lattice theory development in HOL.
  1809 
  1810     constants "meet" and "join" now named "inf" and "sup"
  1811     constant "Meet" now named "Inf"
  1812 
  1813     classes "meet_semilorder" and "join_semilorder" now named
  1814       "lower_semilattice" and "upper_semilattice"
  1815     class "lorder" now named "lattice"
  1816     class "comp_lat" now named "complete_lattice"
  1817 
  1818     Instantiation of lattice classes allows explicit definitions
  1819     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1820 
  1821   INCOMPATIBILITY.  Theorem renames:
  1822 
  1823     meet_left_le            ~> inf_le1
  1824     meet_right_le           ~> inf_le2
  1825     join_left_le            ~> sup_ge1
  1826     join_right_le           ~> sup_ge2
  1827     meet_join_le            ~> inf_sup_ord
  1828     le_meetI                ~> le_infI
  1829     join_leI                ~> le_supI
  1830     le_meet                 ~> le_inf_iff
  1831     le_join                 ~> ge_sup_conv
  1832     meet_idempotent         ~> inf_idem
  1833     join_idempotent         ~> sup_idem
  1834     meet_comm               ~> inf_commute
  1835     join_comm               ~> sup_commute
  1836     meet_leI1               ~> le_infI1
  1837     meet_leI2               ~> le_infI2
  1838     le_joinI1               ~> le_supI1
  1839     le_joinI2               ~> le_supI2
  1840     meet_assoc              ~> inf_assoc
  1841     join_assoc              ~> sup_assoc
  1842     meet_left_comm          ~> inf_left_commute
  1843     meet_left_idempotent    ~> inf_left_idem
  1844     join_left_comm          ~> sup_left_commute
  1845     join_left_idempotent    ~> sup_left_idem
  1846     meet_aci                ~> inf_aci
  1847     join_aci                ~> sup_aci
  1848     le_def_meet             ~> le_iff_inf
  1849     le_def_join             ~> le_iff_sup
  1850     join_absorp2            ~> sup_absorb2
  1851     join_absorp1            ~> sup_absorb1
  1852     meet_absorp1            ~> inf_absorb1
  1853     meet_absorp2            ~> inf_absorb2
  1854     meet_join_absorp        ~> inf_sup_absorb
  1855     join_meet_absorp        ~> sup_inf_absorb
  1856     distrib_join_le         ~> distrib_sup_le
  1857     distrib_meet_le         ~> distrib_inf_le
  1858 
  1859     add_meet_distrib_left   ~> add_inf_distrib_left
  1860     add_join_distrib_left   ~> add_sup_distrib_left
  1861     is_join_neg_meet        ~> is_join_neg_inf
  1862     is_meet_neg_join        ~> is_meet_neg_sup
  1863     add_meet_distrib_right  ~> add_inf_distrib_right
  1864     add_join_distrib_right  ~> add_sup_distrib_right
  1865     add_meet_join_distribs  ~> add_sup_inf_distribs
  1866     join_eq_neg_meet        ~> sup_eq_neg_inf
  1867     meet_eq_neg_join        ~> inf_eq_neg_sup
  1868     add_eq_meet_join        ~> add_eq_inf_sup
  1869     meet_0_imp_0            ~> inf_0_imp_0
  1870     join_0_imp_0            ~> sup_0_imp_0
  1871     meet_0_eq_0             ~> inf_0_eq_0
  1872     join_0_eq_0             ~> sup_0_eq_0
  1873     neg_meet_eq_join        ~> neg_inf_eq_sup
  1874     neg_join_eq_meet        ~> neg_sup_eq_inf
  1875     join_eq_if              ~> sup_eq_if
  1876 
  1877     mono_meet               ~> mono_inf
  1878     mono_join               ~> mono_sup
  1879     meet_bool_eq            ~> inf_bool_eq
  1880     join_bool_eq            ~> sup_bool_eq
  1881     meet_fun_eq             ~> inf_fun_eq
  1882     join_fun_eq             ~> sup_fun_eq
  1883     meet_set_eq             ~> inf_set_eq
  1884     join_set_eq             ~> sup_set_eq
  1885     meet1_iff               ~> inf1_iff
  1886     meet2_iff               ~> inf2_iff
  1887     meet1I                  ~> inf1I
  1888     meet2I                  ~> inf2I
  1889     meet1D1                 ~> inf1D1
  1890     meet2D1                 ~> inf2D1
  1891     meet1D2                 ~> inf1D2
  1892     meet2D2                 ~> inf2D2
  1893     meet1E                  ~> inf1E
  1894     meet2E                  ~> inf2E
  1895     join1_iff               ~> sup1_iff
  1896     join2_iff               ~> sup2_iff
  1897     join1I1                 ~> sup1I1
  1898     join2I1                 ~> sup2I1
  1899     join1I1                 ~> sup1I1
  1900     join2I2                 ~> sup1I2
  1901     join1CI                 ~> sup1CI
  1902     join2CI                 ~> sup2CI
  1903     join1E                  ~> sup1E
  1904     join2E                  ~> sup2E
  1905 
  1906     is_meet_Meet            ~> is_meet_Inf
  1907     Meet_bool_def           ~> Inf_bool_def
  1908     Meet_fun_def            ~> Inf_fun_def
  1909     Meet_greatest           ~> Inf_greatest
  1910     Meet_lower              ~> Inf_lower
  1911     Meet_set_def            ~> Inf_set_def
  1912 
  1913     Sup_def                 ~> Sup_Inf
  1914     Sup_bool_eq             ~> Sup_bool_def
  1915     Sup_fun_eq              ~> Sup_fun_def
  1916     Sup_set_eq              ~> Sup_set_def
  1917 
  1918     listsp_meetI            ~> listsp_infI
  1919     listsp_meet_eq          ~> listsp_inf_eq
  1920 
  1921     meet_min                ~> inf_min
  1922     join_max                ~> sup_max
  1923 
  1924 * Added syntactic class "size"; overloaded constant "size" now has
  1925 type "'a::size ==> bool"
  1926 
  1927 * Internal reorganisation of `size' of datatypes: size theorems
  1928 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1929 simplification rules by default!); theorems "prod.size" now named
  1930 "*.size".
  1931 
  1932 * Class "div" now inherits from class "times" rather than "type".
  1933 INCOMPATIBILITY.
  1934 
  1935 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1936 Linorder etc.  have disappeared; operations defined in terms of
  1937 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1938 
  1939 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1940 
  1941 * HOL-Word: New extensive library and type for generic, fixed size
  1942 machine words, with arithemtic, bit-wise, shifting and rotating
  1943 operations, reflection into int, nat, and bool lists, automation for
  1944 linear arithmetic (by automatic reflection into nat or int), including
  1945 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1946 arithmetic type classes, supporting automatic simplification of
  1947 numerals on all operations.
  1948 
  1949 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1950 
  1951 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1952 
  1953 * Code generator library theories:
  1954   - Code_Integer represents HOL integers by big integer literals in target
  1955     languages.
  1956   - Code_Char represents HOL characters by character literals in target
  1957     languages.
  1958   - Code_Char_chr like Code_Char, but also offers treatment of character
  1959     codes; includes Code_Integer.
  1960   - Executable_Set allows to generate code for finite sets using lists.
  1961   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1962     denominator).
  1963   - Executable_Real implements a subset of real numbers, namly those
  1964     representable by rational numbers.
  1965   - Efficient_Nat implements natural numbers by integers, which in general will
  1966     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1967     includes Code_Integer.
  1968   - Code_Index provides an additional datatype index which is mapped to
  1969     target-language built-in integers.
  1970   - Code_Message provides an additional datatype message_string which is isomorphic to
  1971     strings; messages are mapped to target-language strings.
  1972 
  1973 * New package for inductive predicates
  1974 
  1975   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1976 
  1977     inductive
  1978       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1979       for z_1 :: U_1 and ... and z_n :: U_m
  1980     where
  1981       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1982     | ...
  1983 
  1984   with full support for type-inference, rather than
  1985 
  1986     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1987 
  1988     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1989     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1990 
  1991     inductive "s z_1 ... z_m"
  1992     intros
  1993       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1994       ...
  1995 
  1996   For backward compatibility, there is a wrapper allowing inductive
  1997   sets to be defined with the new package via
  1998 
  1999     inductive_set
  2000       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2001       for z_1 :: U_1 and ... and z_n :: U_m
  2002     where
  2003       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2004     | ...
  2005 
  2006   or
  2007 
  2008     inductive_set
  2009       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2010       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2011       for z_1 :: U_1 and ... and z_n :: U_m
  2012     where
  2013       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2014     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2015     | ...
  2016 
  2017   if the additional syntax "p ..." is required.
  2018 
  2019   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2020   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2021 
  2022   INCOMPATIBILITIES:
  2023 
  2024   - Since declaration and definition of inductive sets or predicates
  2025     is no longer separated, abbreviations involving the newly
  2026     introduced sets or predicates must be specified together with the
  2027     introduction rules after the 'where' keyword (see above), rather
  2028     than before the actual inductive definition.
  2029 
  2030   - The variables in induction and elimination rules are now
  2031     quantified in the order of their occurrence in the introduction
  2032     rules, rather than in alphabetical order. Since this may break
  2033     some proofs, these proofs either have to be repaired, e.g. by
  2034     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2035     statements of the form
  2036 
  2037       case (rule_i a_i_1 ... a_i_{k_i})
  2038 
  2039     or the old order of quantification has to be restored by explicitly adding
  2040     meta-level quantifiers in the introduction rules, i.e.
  2041 
  2042       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2043 
  2044   - The format of the elimination rules is now
  2045 
  2046       p z_1 ... z_m x_1 ... x_n ==>
  2047         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2048         ==> ... ==> P
  2049 
  2050     for predicates and
  2051 
  2052       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2053         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2054         ==> ... ==> P
  2055 
  2056     for sets rather than
  2057 
  2058       x : s z_1 ... z_m ==>
  2059         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2060         ==> ... ==> P
  2061 
  2062     This may require terms in goals to be expanded to n-tuples
  2063     (e.g. using case_tac or simplification with the split_paired_all
  2064     rule) before the above elimination rule is applicable.
  2065 
  2066   - The elimination or case analysis rules for (mutually) inductive
  2067     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2068     list of rules "p_1_..._p_k.elims" is no longer available.
  2069 
  2070 * New package "function"/"fun" for general recursive functions,
  2071 supporting mutual and nested recursion, definitions in local contexts,
  2072 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2073 for small examples, and the separate tutorial on the function
  2074 package. The old recdef "package" is still available as before, but
  2075 users are encouraged to use the new package.
  2076 
  2077 * Method "lexicographic_order" automatically synthesizes termination
  2078 relations as lexicographic combinations of size measures. 
  2079 
  2080 * Case-expressions allow arbitrary constructor-patterns (including
  2081 "_") and take their order into account, like in functional
  2082 programming.  Internally, this is translated into nested
  2083 case-expressions; missing cases are added and mapped to the predefined
  2084 constant "undefined". In complicated cases printing may no longer show
  2085 the original input but the internal form. Lambda-abstractions allow
  2086 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2087 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2088 variable.
  2089 
  2090 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2091 is an abbreviation for "of_nat :: nat => int". The simplification
  2092 rules for "of_nat" have been changed to work like "int" did
  2093 previously.  Potential INCOMPATIBILITY:
  2094   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2095   - of_nat_diff and of_nat_mult are no longer default simp rules
  2096 
  2097 * Method "algebra" solves polynomial equations over (semi)rings using
  2098 Groebner bases. The (semi)ring structure is defined by locales and the
  2099 tool setup depends on that generic context. Installing the method for
  2100 a specific type involves instantiating the locale and possibly adding
  2101 declarations for computation on the coefficients.  The method is
  2102 already instantiated for natural numbers and for the axiomatic class
  2103 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2104 CALCULEMUS 2007 for the general principles underlying this
  2105 architecture of context-aware proof-tools.
  2106 
  2107 * Method "ferrack" implements quantifier elimination over
  2108 special-purpose dense linear orders using locales (analogous to
  2109 "algebra"). The method is already installed for class
  2110 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2111 rat, etc.
  2112 
  2113 * Former constant "List.op @" now named "List.append".  Use ML
  2114 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2115 circumvent possible incompatibilities when working on ML level.
  2116 
  2117 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2118 
  2119 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2120 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2121 
  2122 * New syntax for Haskell-like list comprehension (input only), eg.
  2123 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2124 
  2125 * The special syntax for function "filter" has changed from [x :
  2126 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2127 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2128 
  2129 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2130 defined on nat only, as an abbreviation for [a..<Suc b]
  2131 INCOMPATIBILITY.
  2132 
  2133 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2134 
  2135 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2136 
  2137 * New lemma collection field_simps (an extension of ring_simps) for
  2138 manipulating (in)equations involving division. Multiplies with all
  2139 denominators that can be proved to be non-zero (in equations) or
  2140 positive/negative (in inequations).
  2141 
  2142 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2143 have been improved and renamed to ring_simps, group_simps and
  2144 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2145 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2146 
  2147 * Theory Library/Commutative_Ring: switched from recdef to function
  2148 package; constants add, mul, pow now curried.  Infix syntax for
  2149 algebraic operations.
  2150 
  2151 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2152 INCOMPATIBILITY.
  2153 
  2154 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2155 INCOMPATIBILITY.
  2156 
  2157 * HOL/records: generalised field-update to take a function on the
  2158 field rather than the new value: r(|A := x|) is translated to A_update
  2159 (K x) r The K-combinator that is internally used is called K_record.
  2160 INCOMPATIBILITY: Usage of the plain update functions has to be
  2161 adapted.
  2162  
  2163 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2164 * x = 0, which are required for a semiring.  Richer structures do not
  2165 inherit from semiring_0 anymore, because this property is a theorem
  2166 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2167 there is more to prove, but this is mostly trivial.
  2168 
  2169 * Class "recpower" is generalized to arbitrary monoids, not just
  2170 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2171 commutativity or semiring properties additionally.
  2172 
  2173 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2174 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2175 better use 'abbreviation'.
  2176 
  2177 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2178 
  2179 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2180 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2181 significant changes for setting up numeral syntax for types:
  2182   - New constants Numeral.pred and Numeral.succ instead
  2183       of former Numeral.bin_pred and Numeral.bin_succ.
  2184   - Use integer operations instead of bin_add, bin_mult and so on.
  2185   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2186   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2187 
  2188 See src/HOL/Integ/IntArith.thy for an example setup.
  2189 
  2190 * Command 'normal_form' computes the normal form of a term that may
  2191 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2192 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2193 heavy-duty computations because the functions are compiled to ML
  2194 first.  Correspondingly, a method "normalization" is provided.  See
  2195 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2196 
  2197 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2198 25 like -->); output depends on the "iff" print_mode, the default is
  2199 "A = B" (with priority 50).
  2200 
  2201 * Relations less (<) and less_eq (<=) are also available on type bool.
  2202 Modified syntax to disallow nesting without explicit parentheses,
  2203 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2204 INCOMPATIBILITY.
  2205 
  2206 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2207 
  2208 * Relation composition operator "op O" now has precedence 75 and binds
  2209 stronger than union and intersection. INCOMPATIBILITY.
  2210 
  2211 * The old set interval syntax "{m..n(}" (and relatives) has been
  2212 removed.  Use "{m..<n}" (and relatives) instead.
  2213 
  2214 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2215 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2216 ``declare [[simproc del: neq]]''.
  2217 
  2218 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2219 True/False.
  2220 
  2221 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2222 
  2223 * Theorem setsum_mult renamed to setsum_right_distrib.
  2224 
  2225 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2226 ``rule'' method.
  2227 
  2228 * Reimplemented methods "sat" and "satx", with several improvements:
  2229 goals no longer need to be stated as "<prems> ==> False", equivalences
  2230 (i.e. "=" on type bool) are handled, variable names of the form
  2231 "lit_<n>" are no longer reserved, significant speedup.
  2232 
  2233 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2234 zChaff is still supported as well.
  2235 
  2236 * 'inductive' and 'datatype': provide projections of mutual rules,
  2237 bundled as foo_bar.inducts;
  2238 
  2239 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2240 Library.
  2241 
  2242 * Library: moved theory Accessible_Part to main HOL.
  2243 
  2244 * Library: added theory Coinductive_List of potentially infinite lists
  2245 as greatest fixed-point.
  2246 
  2247 * Library: added theory AssocList which implements (finite) maps as
  2248 association lists.
  2249 
  2250 * Method "evaluation" solves goals (i.e. a boolean expression)
  2251 efficiently by compiling it to ML.  The goal is "proved" (via an
  2252 oracle) if it evaluates to True.
  2253 
  2254 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2255 also when invoked by the simplifier.  This results in the Simplifier
  2256 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2257 Configuration option fast_arith_split_limit=0 recovers the old
  2258 behavior.
  2259 
  2260 * Support for hex (0x20) and binary (0b1001) numerals.
  2261 
  2262 * New method: reify eqs (t), where eqs are equations for an
  2263 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2264 parameter, computes a term s::'b and a list xs::'a list and proves the
  2265 theorem I xs s = t. This is also known as reification or quoting. The
  2266 resulting theorem is applied to the subgoal to substitute t with I xs
  2267 s.  If t is omitted, the subgoal itself is reified.
  2268 
  2269 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2270 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2271 where f is supposed to be a computable function (in the sense of code
  2272 generattion). The method uses reify to compute s and xs as above then
  2273 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2274 r and finally gets the theorem t = r, which is again applied to the
  2275 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2276 
  2277 * Reflection: Automatic reification now handels binding, an example is
  2278 available in src/HOL/ex/ReflectionEx.thy
  2279 
  2280 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2281 command 'statespace' that is similar to 'record', but introduces an
  2282 abstract specification based on the locale infrastructure instead of
  2283 HOL types.  This leads to extra flexibility in composing state spaces,
  2284 in particular multiple inheritance and renaming of components.
  2285 
  2286 
  2287 *** HOL-Complex ***
  2288 
  2289 * Hyperreal: Functions root and sqrt are now defined on negative real
  2290 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2291 Nonnegativity side conditions have been removed from many lemmas, so
  2292 that more subgoals may now be solved by simplification; potential
  2293 INCOMPATIBILITY.
  2294 
  2295 * Real: new type classes formalize real normed vector spaces and
  2296 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2297 and norm :: 'a => real.
  2298 
  2299 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2300 reals into other types. The overloaded constant Reals :: 'a set is now
  2301 defined as range of_real; potential INCOMPATIBILITY.
  2302 
  2303 * Real: proper support for ML code generation, including 'quickcheck'.
  2304 Reals are implemented as arbitrary precision rationals.
  2305 
  2306 * Hyperreal: Several constants that previously worked only for the
  2307 reals have been generalized, so they now work over arbitrary vector
  2308 spaces. Type annotations may need to be added in some cases; potential
  2309 INCOMPATIBILITY.
  2310 
  2311   Infinitesimal  :: ('a::real_normed_vector) star set
  2312   HFinite        :: ('a::real_normed_vector) star set
  2313   HInfinite      :: ('a::real_normed_vector) star set
  2314   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2315   monad          :: ('a::real_normed_vector) star => 'a star set
  2316   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2317   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2318   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2319   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2320   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2321   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2322   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2323   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2324   sgn            :: 'a::real_normed_vector => 'a
  2325   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2326 
  2327 * Complex: Some complex-specific constants are now abbreviations for
  2328 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2329 hnorm.  Other constants have been entirely removed in favor of the
  2330 polymorphic versions (INCOMPATIBILITY):
  2331 
  2332   approx        <-- capprox
  2333   HFinite       <-- CFinite
  2334   HInfinite     <-- CInfinite
  2335   Infinitesimal <-- CInfinitesimal
  2336   monad         <-- cmonad
  2337   galaxy        <-- cgalaxy
  2338   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2339   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2340   (ns)deriv     <-- (ns)cderiv
  2341 
  2342 
  2343 *** HOL-Algebra ***
  2344 
  2345 * Formalisation of ideals and the quotient construction over rings.
  2346 
  2347 * Order and lattice theory no longer based on records.
  2348 INCOMPATIBILITY.
  2349 
  2350 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2351 greatest_closed.  INCOMPATIBILITY.
  2352 
  2353 * Method algebra is now set up via an attribute.  For examples see
  2354 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2355 of algebraic structures.
  2356 
  2357 * Renamed theory CRing to Ring.
  2358 
  2359 
  2360 *** HOL-Nominal ***
  2361 
  2362 * Substantial, yet incomplete support for nominal datatypes (binding
  2363 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2364 src/HOL/Nominal/Examples.  Prospective users should consult
  2365 http://isabelle.in.tum.de/nominal/
  2366 
  2367 
  2368 *** ML ***
  2369 
  2370 * ML basics: just one true type int, which coincides with IntInf.int
  2371 (even on SML/NJ).
  2372 
  2373 * ML within Isar: antiquotations allow to embed statically-checked
  2374 formal entities in the source, referring to the context available at
  2375 compile-time.  For example:
  2376 
  2377 ML {* @{sort "{zero,one}"} *}
  2378 ML {* @{typ "'a => 'b"} *}
  2379 ML {* @{term "%x. x"} *}
  2380 ML {* @{prop "x == y"} *}
  2381 ML {* @{ctyp "'a => 'b"} *}
  2382 ML {* @{cterm "%x. x"} *}
  2383 ML {* @{cprop "x == y"} *}
  2384 ML {* @{thm asm_rl} *}
  2385 ML {* @{thms asm_rl} *}
  2386 ML {* @{type_name c} *}
  2387 ML {* @{type_syntax c} *}
  2388 ML {* @{const_name c} *}
  2389 ML {* @{const_syntax c} *}
  2390 ML {* @{context} *}
  2391 ML {* @{theory} *}
  2392 ML {* @{theory Pure} *}
  2393 ML {* @{theory_ref} *}
  2394 ML {* @{theory_ref Pure} *}
  2395 ML {* @{simpset} *}
  2396 ML {* @{claset} *}
  2397 ML {* @{clasimpset} *}
  2398 
  2399 The same works for sources being ``used'' within an Isar context.
  2400 
  2401 * ML in Isar: improved error reporting; extra verbosity with
  2402 ML_Context.trace enabled.
  2403 
  2404 * Pure/General/table.ML: the join operations now works via exceptions
  2405 DUP/SAME instead of type option. This is simpler in simple cases, and
  2406 admits slightly more efficient complex applications.
  2407 
  2408 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2409 use Context.generic instead of just theory.
  2410 
  2411 * Pure: datatype Context.generic joins theory/Proof.context and
  2412 provides some facilities for code that works in either kind of
  2413 context, notably GenericDataFun for uniform theory and proof data.
  2414 
  2415 * Pure: simplified internal attribute type, which is now always
  2416 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2417 local (Proof.context) attributes have been discontinued, while
  2418 minimizing code duplication. Thm.rule_attribute and
  2419 Thm.declaration_attribute build canonical attributes; see also structure
  2420 Context for further operations on Context.generic, notably
  2421 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2422 declarations and definitions.
  2423 
  2424 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2425 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2426 init only required for impure data. INCOMPATIBILITY: empty really need
  2427 to be empty (no dependencies on theory content!)
  2428 
  2429 * Pure/kernel: consts certification ignores sort constraints given in
  2430 signature declarations. (This information is not relevant to the
  2431 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2432 potential INCOMPATIBILITY.
  2433 
  2434 * Pure: axiomatic type classes are now purely definitional, with
  2435 explicit proofs of class axioms and super class relations performed
  2436 internally. See Pure/axclass.ML for the main internal interfaces --
  2437 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2438 AxClass.axiomatize_class/classrel/arity supersede
  2439 Sign.add_classes/classrel/arities.
  2440 
  2441 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2442 global/local versions on theory vs. Proof.context have been
  2443 discontinued; Attrib.syntax and Method.syntax have been adapted
  2444 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2445 attributes, methods, etc.
  2446 
  2447 * Pure: several functions of signature "... -> theory -> theory * ..."
  2448 have been reoriented to "... -> theory -> ... * theory" in order to
  2449 allow natural usage in combination with the ||>, ||>>, |-> and
  2450 fold_map combinators.
  2451 
  2452 * Pure: official theorem names (closed derivations) and additional
  2453 comments (tags) are now strictly separate.  Name hints -- which are
  2454 maintained as tags -- may be attached any time without affecting the
  2455 derivation.
  2456 
  2457 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2458 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2459 achieve the old behaviour.
  2460 
  2461 * Pure: the "Goal" constant is now called "prop", supporting a
  2462 slightly more general idea of ``protecting'' meta-level rule
  2463 statements.
  2464 
  2465 * Pure: Logic.(un)varify only works in a global context, which is now
  2466 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2467 Logic.legacy_(un)varify as temporary workaround.
  2468 
  2469 * Pure: structure Name provides scalable operations for generating
  2470 internal variable names, notably Name.variants etc.  This replaces
  2471 some popular functions from term.ML:
  2472 
  2473   Term.variant		->  Name.variant
  2474   Term.variantlist	->  Name.variant_list
  2475   Term.invent_names	->  Name.invent_list
  2476 
  2477 Note that low-level renaming rarely occurs in new code -- operations
  2478 from structure Variable are used instead (see below).
  2479 
  2480 * Pure: structure Variable provides fundamental operations for proper
  2481 treatment of fixed/schematic variables in a context.  For example,
  2482 Variable.import introduces fixes for schematics of given facts and
  2483 Variable.export reverses the effect (up to renaming) -- this replaces
  2484 various freeze_thaw operations.
  2485 
  2486 * Pure: structure Goal provides simple interfaces for
  2487 init/conclude/finish and tactical prove operations (replacing former
  2488 Tactic.prove).  Goal.prove is the canonical way to prove results
  2489 within a given context; Goal.prove_global is a degraded version for
  2490 theory level goals, including a global Drule.standard.  Note that
  2491 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2492 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2493 in a locale context).
  2494 
  2495 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2496 and type checking (Syntax.check_term etc.), with common combinations
  2497 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2498 which are considered legacy and await removal.
  2499 
  2500 * Pure/Syntax: generic interfaces for type unchecking
  2501 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2502 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2503 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2504 available for convenience, but refer to the very same operations using
  2505 a mere theory instead of a full context.
  2506 
  2507 * Isar: simplified treatment of user-level errors, using exception
  2508 ERROR of string uniformly.  Function error now merely raises ERROR,
  2509 without any side effect on output channels.  The Isar toplevel takes
  2510 care of proper display of ERROR exceptions.  ML code may use plain
  2511 handle/can/try; cat_error may be used to concatenate errors like this:
  2512 
  2513   ... handle ERROR msg => cat_error msg "..."
  2514 
  2515 Toplevel ML code (run directly or through the Isar toplevel) may be
  2516 embedded into the Isar toplevel with exception display/debug like
  2517 this:
  2518 
  2519   Isar.toplevel (fn () => ...)
  2520 
  2521 INCOMPATIBILITY, removed special transform_error facilities, removed
  2522 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2523 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2524 -- use plain ERROR instead.
  2525 
  2526 * Isar: theory setup now has type (theory -> theory), instead of a
  2527 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2528 
  2529 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2530 ProofContext.debug/verbose flags.
  2531 
  2532 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2533 theory before entering a proof state.  Transactions now always see a
  2534 quasi-functional intermediate checkpoint, both in interactive and
  2535 batch mode.
  2536 
  2537 * Isar: simplified interfaces for outer syntax.  Renamed
  2538 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2539 OuterSyntax.add_parsers -- this functionality is now included in
  2540 OuterSyntax.command etc.  INCOMPATIBILITY.
  2541 
  2542 * Simplifier: the simpset of a running simplification process now
  2543 contains a proof context (cf. Simplifier.the_context), which is the
  2544 very context that the initial simpset has been retrieved from (by
  2545 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2546 (solver, looper etc.) may depend on arbitrary proof data.
  2547 
  2548 * Simplifier.inherit_context inherits the proof context (plus the
  2549 local bounds) of the current simplification process; any simproc
  2550 etc. that calls the Simplifier recursively should do this!  Removed
  2551 former Simplifier.inherit_bounds, which is already included here --
  2552 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2553 specify an explicit context using Simplifier.context/theory_context.
  2554 
  2555 * Simplifier/Classical Reasoner: more abstract interfaces
  2556 change_simpset/claset for modifying the simpset/claset reference of a
  2557 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2558 INCOMPATIBILITY.
  2559 
  2560 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2561 "Trueprop" etc.
  2562 
  2563 
  2564 *** System ***
  2565 
  2566 * settings: the default heap location within ISABELLE_HOME_USER now
  2567 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2568 Isabelle installations.
  2569 
  2570 * isabelle-process: option -S (secure mode) disables some critical
  2571 operations, notably runtime compilation and evaluation of ML source
  2572 code.
  2573 
  2574 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2575 
  2576 * Support for parallel execution, using native multicore support of
  2577 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2578 independent theories, according to the given theory header
  2579 specifications. The maximum number of worker threads is specified via
  2580 usedir option -M or the "max-threads" setting in Proof General. A
  2581 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2582 to 6 on a 8-core machine.  User-code needs to observe certain
  2583 guidelines for thread-safe programming, see appendix A in the Isar
  2584 Implementation manual.
  2585 
  2586 
  2587 
  2588 New in Isabelle2005 (October 2005)
  2589 ----------------------------------
  2590 
  2591 *** General ***
  2592 
  2593 * Theory headers: the new header syntax for Isar theories is
  2594 
  2595   theory <name>
  2596   imports <theory1> ... <theoryN>
  2597   uses <file1> ... <fileM>
  2598   begin
  2599 
  2600 where the 'uses' part is optional.  The previous syntax
  2601 
  2602   theory <name> = <theory1> + ... + <theoryN>:
  2603 
  2604 will disappear in the next release.  Use isatool fixheaders to convert
  2605 existing theory files.  Note that there is no change in ancient
  2606 non-Isar theories now, but these will disappear soon.
  2607 
  2608 * Theory loader: parent theories can now also be referred to via
  2609 relative and absolute paths.
  2610 
  2611 * Command 'find_theorems' searches for a list of criteria instead of a
  2612 list of constants. Known criteria are: intro, elim, dest, name:string,
  2613 simp:term, and any term. Criteria can be preceded by '-' to select
  2614 theorems that do not match. Intro, elim, dest select theorems that
  2615 match the current goal, name:s selects theorems whose fully qualified
  2616 name contain s, and simp:term selects all simplification rules whose
  2617 lhs match term.  Any other term is interpreted as pattern and selects
  2618 all theorems matching the pattern. Available in ProofGeneral under
  2619 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2620 
  2621   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2622 
  2623 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2624 matching the current goal as introduction rule and not having "HOL."
  2625 in their name (i.e. not being defined in theory HOL).
  2626 
  2627 * Command 'thms_containing' has been discontinued in favour of
  2628 'find_theorems'; INCOMPATIBILITY.
  2629 
  2630 * Communication with Proof General is now 8bit clean, which means that
  2631 Unicode text in UTF-8 encoding may be used within theory texts (both
  2632 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2633 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2634 
  2635   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2636   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2637 
  2638 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2639 Classical Reasoner.  Typical big applications run around 2 times
  2640 faster.
  2641 
  2642 
  2643 *** Document preparation ***
  2644 
  2645 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2646 of raw sources.  Only those symbols that do not require additional
  2647 LaTeX packages (depending on comments in isabellesym.sty) are
  2648 displayed properly, everything else is left verbatim.  isatool display
  2649 and isatool print are used as front ends (these are subject to the
  2650 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2651 
  2652 * Command tags control specific markup of certain regions of text,
  2653 notably folding and hiding.  Predefined tags include "theory" (for
  2654 theory begin and end), "proof" for proof commands, and "ML" for
  2655 commands involving ML code; the additional tags "visible" and
  2656 "invisible" are unused by default.  Users may give explicit tag
  2657 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2658 interpretation of tags is determined by the LaTeX job during document
  2659 preparation: see option -V of isatool usedir, or options -n and -t of
  2660 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2661 \isadroptag.
  2662 
  2663 Several document versions may be produced at the same time via isatool
  2664 usedir (the generated index.html will link all of them).  Typical
  2665 specifications include ''-V document=theory,proof,ML'' to present
  2666 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2667 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2668 these parts without any formal replacement text.  The Isabelle site
  2669 default settings produce ''document'' and ''outline'' versions as
  2670 specified above.
  2671 
  2672 * Several new antiquotations:
  2673 
  2674   @{term_type term} prints a term with its type annotated;
  2675 
  2676   @{typeof term} prints the type of a term;
  2677 
  2678   @{const const} is the same as @{term const}, but checks that the
  2679   argument is a known logical constant;
  2680 
  2681   @{term_style style term} and @{thm_style style thm} print a term or
  2682   theorem applying a "style" to it
  2683 
  2684   @{ML text}
  2685 
  2686 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2687 definitions, equations, inequations etc., 'concl' printing only the
  2688 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2689 to print the specified premise.  TermStyle.add_style provides an ML
  2690 interface for introducing further styles.  See also the "LaTeX Sugar"
  2691 document practical applications.  The ML antiquotation prints
  2692 type-checked ML expressions verbatim.
  2693 
  2694 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2695 and 'text' support optional locale specification '(in loc)', which
  2696 specifies the default context for interpreting antiquotations.  For
  2697 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2698 
  2699 * Option 'locale=NAME' of antiquotations specifies an alternative
  2700 context interpreting the subsequent argument.  For example: @{thm
  2701 [locale=lattice] inf_assoc}.
  2702 
  2703 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2704 a proof context.
  2705 
  2706 * Proper output of antiquotations for theory commands involving a
  2707 proof context (such as 'locale' or 'theorem (in loc) ...').
  2708 
  2709 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2710 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2711 
  2712 * isatool usedir: new option -C (default true) controls whether option
  2713 -D should include a copy of the original document directory; -C false
  2714 prevents unwanted effects such as copying of administrative CVS data.
  2715 
  2716 
  2717 *** Pure ***
  2718 
  2719 * Considerably improved version of 'constdefs' command.  Now performs
  2720 automatic type-inference of declared constants; additional support for
  2721 local structure declarations (cf. locales and HOL records), see also
  2722 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2723 sequential dependencies of definitions within a single 'constdefs'
  2724 section; moreover, the declared name needs to be an identifier.  If
  2725 all fails, consider to fall back on 'consts' and 'defs' separately.
  2726 
  2727 * Improved indexed syntax and implicit structures.  First of all,
  2728 indexed syntax provides a notational device for subscripted
  2729 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2730 expressions.  Secondly, in a local context with structure
  2731 declarations, number indexes \<^sub>n or the empty index (default
  2732 number 1) refer to a certain fixed variable implicitly; option
  2733 show_structs controls printing of implicit structures.  Typical
  2734 applications of these concepts involve record types and locales.
  2735 
  2736 * New command 'no_syntax' removes grammar declarations (and
  2737 translations) resulting from the given syntax specification, which is
  2738 interpreted in the same manner as for the 'syntax' command.
  2739 
  2740 * 'Advanced' translation functions (parse_translation etc.) may depend
  2741 on the signature of the theory context being presently used for
  2742 parsing/printing, see also isar-ref manual.
  2743 
  2744 * Improved 'oracle' command provides a type-safe interface to turn an
  2745 ML expression of type theory -> T -> term into a primitive rule of
  2746 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2747 is already included here); see also FOL/ex/IffExample.thy;
  2748 INCOMPATIBILITY.
  2749 
  2750 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2751 before); "cI" is no longer bound, use "c.intro" instead.
  2752 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2753 axclasses vs. locales.
  2754 
  2755 * Improved internal renaming of symbolic identifiers -- attach primes
  2756 instead of base 26 numbers.
  2757 
  2758 * New flag show_question_marks controls printing of leading question
  2759 marks in schematic variable names.
  2760 
  2761 * In schematic variable names, *any* symbol following \<^isub> or
  2762 \<^isup> is now treated as part of the base name.  For example, the
  2763 following works without printing of awkward ".0" indexes:
  2764 
  2765   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2766     by simp
  2767 
  2768 * Inner syntax includes (*(*nested*) comments*).
  2769 
  2770 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2771 annotations as "(00...)".
  2772 
  2773 * Clear separation of logical types and nonterminals, where the latter
  2774 may only occur in 'syntax' specifications or type abbreviations.
  2775 Before that distinction was only partially implemented via type class
  2776 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2777 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2778 exotic syntax specifications may require further adaption
  2779 (e.g. Cube/Cube.thy).
  2780 
  2781 * Removed obsolete type class "logic", use the top sort {} instead.
  2782 Note that non-logical types should be declared as 'nonterminals'
  2783 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2784 specifications.
  2785 
  2786 * Attributes 'induct' and 'cases': type or set names may now be
  2787 locally fixed variables as well.
  2788 
  2789 * Simplifier: can now control the depth to which conditional rewriting
  2790 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2791 Limit.
  2792 
  2793 * Simplifier: simplification procedures may now take the current
  2794 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2795 interface), which is very useful for calling the Simplifier
  2796 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2797 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2798 low-level mk_simproc no longer applies Logic.varify internally, to
  2799 allow for use in a context of fixed variables.
  2800 
  2801 * thin_tac now works even if the assumption being deleted contains !!
  2802 or ==>.  More generally, erule now works even if the major premise of
  2803 the elimination rule contains !! or ==>.
  2804 
  2805 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2806 
  2807 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2808 from Pure, which contains all common declarations already.  Both
  2809 theories are defined via plain Isabelle/Isar .thy files.
  2810 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2811 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2812 use isatool fixcpure to adapt your theory and ML sources.
  2813 
  2814 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2815 selections of theorems in named facts via index ranges.
  2816 
  2817 * 'print_theorems': in theory mode, really print the difference
  2818 wrt. the last state (works for interactive theory development only),
  2819 in proof mode print all local facts (cf. 'print_facts');
  2820 
  2821 * 'hide': option '(open)' hides only base names.
  2822 
  2823 * More efficient treatment of intermediate checkpoints in interactive
  2824 theory development.
  2825 
  2826 * Code generator is now invoked via code_module (incremental code
  2827 generation) and code_library (modular code generation, ML structures
  2828 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2829 must be quoted when used as identifiers.
  2830 
  2831 * New 'value' command for reading, evaluating and printing terms using
  2832 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2833 quoted when used as identifier.
  2834 
  2835 
  2836 *** Locales ***
  2837 
  2838 * New commands for the interpretation of locale expressions in
  2839 theories (1), locales (2) and proof contexts (3).  These generate
  2840 proof obligations from the expression specification.  After the
  2841 obligations have been discharged, theorems of the expression are added
  2842 to the theory, target locale or proof context.  The synopsis of the
  2843 commands is a follows:
  2844 
  2845   (1) interpretation expr inst
  2846   (2) interpretation target < expr
  2847   (3) interpret expr inst
  2848 
  2849 Interpretation in theories and proof contexts require a parameter
  2850 instantiation of terms from the current context.  This is applied to
  2851 specifications and theorems of the interpreted expression.
  2852 Interpretation in locales only permits parameter renaming through the
  2853 locale expression.  Interpretation is smart in that interpretations
  2854 that are active already do not occur in proof obligations, neither are
  2855 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2856 inspect active interpretations of a particular locale.  For details,
  2857 see the Isar Reference manual.  Examples can be found in
  2858 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2859 
  2860 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2861 'interpret' instead.
  2862 
  2863 * New context element 'constrains' for adding type constraints to
  2864 parameters.
  2865 
  2866 * Context expressions: renaming of parameters with syntax
  2867 redeclaration.
  2868 
  2869 * Locale declaration: 'includes' disallowed.
  2870 
  2871 * Proper static binding of attribute syntax -- i.e. types / terms /
  2872 facts mentioned as arguments are always those of the locale definition
  2873 context, independently of the context of later invocations.  Moreover,
  2874 locale operations (renaming and type / term instantiation) are applied
  2875 to attribute arguments as expected.
  2876 
  2877 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2878 actual attributes; rare situations may require Attrib.attribute to
  2879 embed those attributes into Attrib.src that lack concrete syntax.
  2880 Attribute implementations need to cooperate properly with the static
  2881 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2882 Attrib.XXX_thm etc. already do the right thing without further
  2883 intervention.  Only unusual applications -- such as "where" or "of"
  2884 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2885 on the context and the facts involved -- may have to assign parsed
  2886 values to argument tokens explicitly.
  2887 
  2888 * Changed parameter management in theorem generation for long goal
  2889 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2890 theorem statement in rare situations.
  2891 
  2892 * Locale inspection command 'print_locale' omits notes elements.  Use
  2893 'print_locale!' to have them included in the output.
  2894 
  2895 
  2896 *** Provers ***
  2897 
  2898 * Provers/hypsubst.ML: improved version of the subst method, for
  2899 single-step rewriting: it now works in bound variable contexts. New is
  2900 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2901 rewrite a different subterm than the original subst method, which is
  2902 still available as 'simplesubst'.
  2903 
  2904 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2905 and quasi orders.
  2906 
  2907 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2908 reflexive-transitive closure of relations.
  2909 
  2910 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2911 limit (previously hard-coded with a value of 20) user-definable.
  2912 
  2913 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2914 is peformed already.  Object-logics merely need to finish their
  2915 initial simpset configuration as before.  INCOMPATIBILITY.
  2916 
  2917 
  2918 *** HOL ***
  2919 
  2920 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2921 
  2922   syntax (epsilon)
  2923     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2924 
  2925 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2926 and x-symbol; use option '-m epsilon' to get it actually printed.
  2927 Moreover, the mathematically important symbolic identifier \<epsilon>
  2928 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2929 
  2930 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2931 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2932 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2933 support corresponding Isar calculations.
  2934 
  2935 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2936 instead of ":".
  2937 
  2938 * theory SetInterval: changed the syntax for open intervals:
  2939 
  2940   Old       New
  2941   {..n(}    {..<n}
  2942   {)n..}    {n<..}
  2943   {m..n(}   {m..<n}
  2944   {)m..n}   {m<..n}
  2945   {)m..n(}  {m<..<n}
  2946 
  2947 The old syntax is still supported but will disappear in the next
  2948 release.  For conversion use the following Emacs search and replace
  2949 patterns (these are not perfect but work quite well):
  2950 
  2951   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2952   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2953 
  2954 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2955 equalities in commutative rings; method 'algebra' provides a generic
  2956 interface.
  2957 
  2958 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2959 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2960 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2961 be a tuple pattern.
  2962 
  2963 Some new syntax forms are available:
  2964 
  2965   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2966   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2967   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2968   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2969 
  2970 The latter form "\<Sum>x < k. e" used to be based on a separate
  2971 function "Summation", which has been discontinued.
  2972 
  2973 * theory Finite_Set: in structured induction proofs, the insert case
  2974 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2975 (insert F x)'.
  2976 
  2977 * The 'refute' command has been extended to support a much larger
  2978 fragment of HOL, including axiomatic type classes, constdefs and
  2979 typedefs, inductive datatypes and recursion.
  2980 
  2981 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2982 Requires zChaff with proof generation to be installed.  See
  2983 HOL/ex/SAT_Examples.thy for examples.
  2984 
  2985 * Datatype induction via method 'induct' now preserves the name of the
  2986 induction variable. For example, when proving P(xs::'a list) by
  2987 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2988 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2989 in unstructured proof scripts.
  2990 
  2991 * Reworked implementation of records.  Improved scalability for
  2992 records with many fields, avoiding performance problems for type
  2993 inference. Records are no longer composed of nested field types, but
  2994 of nested extension types. Therefore the record type only grows linear
  2995 in the number of extensions and not in the number of fields.  The
  2996 top-level (users) view on records is preserved.  Potential
  2997 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2998 old record representation. The type generated for a record is called
  2999 <record_name>_ext_type.
  3000 
  3001 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3002 proofs triggered by a record definition or a simproc (if
  3003 quick_and_dirty is enabled).  Definitions of large records can take
  3004 quite long.
  3005 
  3006 New simproc record_upd_simproc for simplification of multiple record
  3007 updates enabled by default.  Moreover, trivial updates are also
  3008 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3009 occasionally, since simplification is more powerful by default.
  3010 
  3011 * typedef: proper support for polymorphic sets, which contain extra
  3012 type-variables in the term.
  3013 
  3014 * Simplifier: automatically reasons about transitivity chains
  3015 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3016 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3017 old proofs break occasionally as simplification may now solve more
  3018 goals than previously.
  3019 
  3020 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3021 present.  Works for all partial orders (class "order"), in particular
  3022 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3023 just like y <= x.
  3024 
  3025 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3026 bound variable or a constant then the let is unfolded.  Otherwise
  3027 first a is simplified to b, and then f b is simplified to g. If
  3028 possible we abstract b from g arriving at "let x = b in h x",
  3029 otherwise we unfold the let and arrive at g.  The simproc can be
  3030 enabled/disabled by the reference use_let_simproc.  Potential
  3031 INCOMPATIBILITY since simplification is more powerful by default.
  3032 
  3033 * Classical reasoning: the meson method now accepts theorems as arguments.
  3034 
  3035 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3036 jobs to provide advice on the provability of subgoals.
  3037 
  3038 * Theory OrderedGroup and Ring_and_Field: various additions and
  3039 improvements to faciliate calculations involving equalities and
  3040 inequalities.
  3041 
  3042 The following theorems have been eliminated or modified
  3043 (INCOMPATIBILITY):
  3044 
  3045   abs_eq             now named abs_of_nonneg
  3046   abs_of_ge_0        now named abs_of_nonneg
  3047   abs_minus_eq       now named abs_of_nonpos
  3048   imp_abs_id         now named abs_of_nonneg
  3049   imp_abs_neg_id     now named abs_of_nonpos
  3050   mult_pos           now named mult_pos_pos
  3051   mult_pos_le        now named mult_nonneg_nonneg
  3052   mult_pos_neg_le    now named mult_nonneg_nonpos
  3053   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3054   mult_neg           now named mult_neg_neg
  3055   mult_neg_le        now named mult_nonpos_nonpos
  3056 
  3057 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3058      
  3059      zero_le_square
  3060      not_square_less_zero 
  3061 
  3062   The following lemmas have been deleted from Real/RealPow:
  3063   
  3064      realpow_zero_zero
  3065      realpow_two
  3066      realpow_less
  3067      zero_le_power
  3068      realpow_two_le
  3069      abs_realpow_two
  3070      realpow_two_abs     
  3071 
  3072 * Theory Parity: added rules for simplifying exponents.
  3073 
  3074 * Theory List:
  3075 
  3076 The following theorems have been eliminated or modified
  3077 (INCOMPATIBILITY):
  3078 
  3079   list_all_Nil       now named list_all.simps(1)
  3080   list_all_Cons      now named list_all.simps(2)
  3081   list_all_conv      now named list_all_iff
  3082   set_mem_eq         now named mem_iff
  3083 
  3084 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3085 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3086 
  3087 
  3088 *** HOL-Complex ***
  3089 
  3090 * Theory RealDef: better support for embedding natural numbers and
  3091 integers in the reals.
  3092 
  3093 The following theorems have been eliminated or modified
  3094 (INCOMPATIBILITY):
  3095 
  3096   exp_ge_add_one_self  now requires no hypotheses
  3097   real_of_int_add      reversed direction of equality (use [symmetric])
  3098   real_of_int_minus    reversed direction of equality (use [symmetric])
  3099   real_of_int_diff     reversed direction of equality (use [symmetric])
  3100   real_of_int_mult     reversed direction of equality (use [symmetric])
  3101 
  3102 * Theory RComplete: expanded support for floor and ceiling functions.
  3103 
  3104 * Theory Ln is new, with properties of the natural logarithm
  3105 
  3106 * Hyperreal: There is a new type constructor "star" for making
  3107 nonstandard types.  The old type names are now type synonyms:
  3108 
  3109   hypreal = real star
  3110   hypnat = nat star
  3111   hcomplex = complex star
  3112 
  3113 * Hyperreal: Many groups of similarly-defined constants have been
  3114 replaced by polymorphic versions (INCOMPATIBILITY):
  3115 
  3116   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3117 
  3118   starset      <-- starsetNat, starsetC
  3119   *s*          <-- *sNat*, *sc*
  3120   starset_n    <-- starsetNat_n, starsetC_n
  3121   *sn*         <-- *sNatn*, *scn*
  3122   InternalSets <-- InternalNatSets, InternalCSets
  3123 
  3124   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3125   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3126   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3127   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3128   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3129 
  3130 * Hyperreal: Many type-specific theorems have been removed in favor of
  3131 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3132 
  3133   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3134   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3135   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3136   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3137   right_minus <-- hypreal_add_minus
  3138   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3139   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3140   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3141   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3142   mult_1_right <-- hcomplex_mult_one_right
  3143   mult_zero_left <-- hcomplex_mult_zero_left
  3144   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3145   right_distrib <-- hypnat_add_mult_distrib2
  3146   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3147   right_inverse <-- hypreal_mult_inverse
  3148   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3149   order_refl <-- {hypreal,hypnat}_le_refl
  3150   order_trans <-- {hypreal,hypnat}_le_trans
  3151   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3152   order_less_le <-- {hypreal,hypnat}_less_le
  3153   linorder_linear <-- {hypreal,hypnat}_le_linear
  3154   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3155   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3156   add_nonneg_nonneg <-- hypreal_le_add_order
  3157 
  3158 * Hyperreal: Separate theorems having to do with type-specific
  3159 versions of constants have been merged into theorems that apply to the
  3160 new polymorphic constants (INCOMPATIBILITY):
  3161 
  3162   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3163   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3164   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3165   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3166   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3167   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3168   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3169   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3170   STAR_diff <-- {STAR,STARC}_diff
  3171   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3172     STARC_hcomplex_of_complex}_image_subset
  3173   starset_n_Un <-- starset{Nat,C}_n_Un
  3174   starset_n_Int <-- starset{Nat,C}_n_Int
  3175   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3176   starset_n_diff <-- starset{Nat,C}_n_diff
  3177   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3178   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3179   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3180   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3181   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3182   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3183   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3184   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3185   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3186   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3187   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3188   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3189   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3190   starfun_diff <-- starfun{C,RC,CR}_diff
  3191   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3192   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3193   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3194   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3195   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3196   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3197   starfun_Id <-- starfunC_Id
  3198   starfun_approx <-- starfun{Nat,CR}_approx
  3199   starfun_capprox <-- starfun{C,RC}_capprox
  3200   starfun_abs <-- starfunNat_rabs
  3201   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3202   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3203   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3204   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3205   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3206   starfun_add_approx <-- starfunCR_add_approx
  3207   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3208   starfun_divide <-- starfun{C,CR,RC}_divide
  3209   starfun_n <-- starfun{Nat,C}_n
  3210   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3211   starfun_n_add <-- starfun{Nat,C}_n_add
  3212   starfun_n_add_minus <-- starfunNat_n_add_minus
  3213   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3214   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3215   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3216 
  3217   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3218   star_n_minus <-- {hypreal,hcomplex}_minus
  3219   star_n_diff <-- {hypreal,hcomplex}_diff
  3220   star_n_mult <-- {hypreal,hcomplex}_mult
  3221   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3222   star_n_le <-- {hypreal,hypnat}_le
  3223   star_n_less <-- {hypreal,hypnat}_less
  3224   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3225   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3226   star_n_abs <-- hypreal_hrabs
  3227   star_n_divide <-- hcomplex_divide
  3228 
  3229   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3230   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3231   star_of_diff <-- hypreal_of_real_diff
  3232   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3233   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3234   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3235   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3236   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3237   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3238   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3239   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3240   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3241   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3242   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3243   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3244   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3245   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3246   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3247   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3248   star_of_power <-- hypreal_of_real_power
  3249   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3250 
  3251 * Hyperreal: new method "transfer" that implements the transfer
  3252 principle of nonstandard analysis. With a subgoal that mentions
  3253 nonstandard types like "'a star", the command "apply transfer"
  3254 replaces it with an equivalent one that mentions only standard types.
  3255 To be successful, all free variables must have standard types; non-
  3256 standard variables must have explicit universal quantifiers.
  3257 
  3258 * Hyperreal: A theory of Taylor series.
  3259 
  3260 
  3261 *** HOLCF ***
  3262 
  3263 * Discontinued special version of 'constdefs' (which used to support
  3264 continuous functions) in favor of the general Pure one with full
  3265 type-inference.
  3266 
  3267 * New simplification procedure for solving continuity conditions; it
  3268 is much faster on terms with many nested lambda abstractions (cubic
  3269 instead of exponential time).
  3270 
  3271 * New syntax for domain package: selector names are now optional.
  3272 Parentheses should be omitted unless argument is lazy, for example:
  3273 
  3274   domain 'a stream = cons "'a" (lazy "'a stream")
  3275 
  3276 * New command 'fixrec' for defining recursive functions with pattern
  3277 matching; defining multiple functions with mutual recursion is also
  3278 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3279 sinr, or any data constructor defined by the domain package. The given
  3280 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3281 syntax and examples.
  3282 
  3283 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3284 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3285 but the proof obligation additionally includes an admissibility
  3286 requirement. The packages generate instances of class cpo or pcpo,
  3287 with continuity and strictness theorems for Rep and Abs.
  3288 
  3289 * HOLCF: Many theorems have been renamed according to a more standard naming
  3290 scheme (INCOMPATIBILITY):
  3291 
  3292   foo_inject:  "foo$x = foo$y ==> x = y"
  3293   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3294   foo_less:    "(foo$x << foo$y) = (x << y)"
  3295   foo_strict:  "foo$UU = UU"
  3296   foo_defined: "... ==> foo$x ~= UU"
  3297   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3298 
  3299 
  3300 *** ZF ***
  3301 
  3302 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3303 including the First Isomorphism Theorem (on quotienting by the kernel
  3304 of a homomorphism).
  3305 
  3306 * ZF/Simplifier: install second copy of type solver that actually
  3307 makes use of TC rules declared to Isar proof contexts (or locales);
  3308 the old version is still required for ML proof scripts.
  3309 
  3310 
  3311 *** Cube ***
  3312 
  3313 * Converted to Isar theory format; use locales instead of axiomatic
  3314 theories.
  3315 
  3316 
  3317 *** ML ***
  3318 
  3319 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3320 for ||>, ||>>, |>>,
  3321 
  3322 * Pure/library.ML no longer defines its own option datatype, but uses
  3323 that of the SML basis, which has constructors NONE and SOME instead of
  3324 None and Some, as well as exception Option.Option instead of OPTION.
  3325 The functions the, if_none, is_some, is_none have been adapted
  3326 accordingly, while Option.map replaces apsome.
  3327 
  3328 * Pure/library.ML: the exception LIST has been given up in favour of
  3329 the standard exceptions Empty and Subscript, as well as
  3330 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3331 superceded by the standard hd and tl functions etc.
  3332 
  3333 A number of basic list functions are no longer exported to the ML
  3334 toplevel, as they are variants of predefined functions.  The following
  3335 suggests how one can translate existing code:
  3336 
  3337     rev_append xs ys = List.revAppend (xs, ys)
  3338     nth_elem (i, xs) = List.nth (xs, i)
  3339     last_elem xs = List.last xs
  3340     flat xss = List.concat xss
  3341     seq fs = List.app fs
  3342     partition P xs = List.partition P xs
  3343     mapfilter f xs = List.mapPartial f xs
  3344 
  3345 * Pure/library.ML: several combinators for linear functional
  3346 transformations, notably reverse application and composition:
  3347 
  3348   x |> f                f #> g
  3349   (x, y) |-> f          f #-> g
  3350 
  3351 * Pure/library.ML: introduced/changed precedence of infix operators:
  3352 
  3353   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3354   infix 2 ?;
  3355   infix 3 o oo ooo oooo;
  3356   infix 4 ~~ upto downto;
  3357 
  3358 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3359 infix operators.
  3360 
  3361 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3362 fold_map support linear functional transformations and nesting.  For
  3363 example:
  3364 
  3365   fold f [x1, ..., xN] y =
  3366     y |> f x1 |> ... |> f xN
  3367 
  3368   (fold o fold) f [xs1, ..., xsN] y =
  3369     y |> fold f xs1 |> ... |> fold f xsN
  3370 
  3371   fold f [x1, ..., xN] =
  3372     f x1 #> ... #> f xN
  3373 
  3374   (fold o fold) f [xs1, ..., xsN] =
  3375     fold f xs1 #> ... #> fold f xsN
  3376 
  3377 * Pure/library.ML: the following selectors on type 'a option are
  3378 available:
  3379 
  3380   the:               'a option -> 'a  (*partial*)
  3381   these:             'a option -> 'a  where 'a = 'b list
  3382   the_default: 'a -> 'a option -> 'a
  3383   the_list:          'a option -> 'a list
  3384 
  3385 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3386 basic operations for association lists, following natural argument
  3387 order; moreover the explicit equality predicate passed here avoids
  3388 potentially expensive polymorphic runtime equality checks.
  3389 The old functions may be expressed as follows:
  3390 
  3391   assoc = uncurry (AList.lookup (op =))
  3392   assocs = these oo AList.lookup (op =)
  3393   overwrite = uncurry (AList.update (op =)) o swap
  3394 
  3395 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3396 
  3397   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3398   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3399 
  3400 replacing make_keylist and keyfilter (occassionally used)
  3401 Naive rewrites:
  3402 
  3403   make_keylist = AList.make
  3404   keyfilter = AList.find (op =)
  3405 
  3406 * eq_fst and eq_snd now take explicit equality parameter, thus
  3407   avoiding eqtypes. Naive rewrites:
  3408 
  3409     eq_fst = eq_fst (op =)
  3410     eq_snd = eq_snd (op =)
  3411 
  3412 * Removed deprecated apl and apr (rarely used).
  3413   Naive rewrites:
  3414 
  3415     apl (n, op) =>>= curry op n
  3416     apr (op, m) =>>= fn n => op (n, m)
  3417 
  3418 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3419 provides a reasonably efficient light-weight implementation of sets as
  3420 lists.
  3421 
  3422 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3423 few new operations; existing lookup and update are now curried to
  3424 follow natural argument order (for use with fold etc.);
  3425 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3426 
  3427 * Pure/General: output via the Isabelle channels of
  3428 writeln/warning/error etc. is now passed through Output.output, with a
  3429 hook for arbitrary transformations depending on the print_mode
  3430 (cf. Output.add_mode -- the first active mode that provides a output
  3431 function wins).  Already formatted output may be embedded into further
  3432 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3433 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3434 accommodate easy composition of diagnostic messages etc.  Programmers
  3435 rarely need to care about Output.output or Output.raw at all, with
  3436 some notable exceptions: Output.output is required when bypassing the
  3437 standard channels (writeln etc.), or in token translations to produce
  3438 properly formatted results; Output.raw is required when capturing
  3439 already output material that will eventually be presented to the user
  3440 a second time.  For the default print mode, both Output.output and
  3441 Output.raw have no effect.
  3442 
  3443 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3444 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3445 cumulative results are displayed at the end of a batch session.
  3446 
  3447 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3448 replaced by File.platform_path and File.shell_path (with appropriate
  3449 hooks).  This provides a clean interface for unusual systems where the
  3450 internal and external process view of file names are different.
  3451 
  3452 * Pure: more efficient orders for basic syntactic entities: added
  3453 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3454 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3455 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3456 orders now -- potential INCOMPATIBILITY for code that depends on a
  3457 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3458 Library.sort_strings on result).
  3459 
  3460 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3461 fold_types traverse types/terms from left to right, observing natural
  3462 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3463 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3464 
  3465 * Pure: name spaces have been refined, with significant changes of the
  3466 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3467 to extern(_table).  The plain name entry path is superceded by a
  3468 general 'naming' context, which also includes the 'policy' to produce
  3469 a fully qualified name and external accesses of a fully qualified
  3470 name; NameSpace.extend is superceded by context dependent
  3471 Sign.declare_name.  Several theory and proof context operations modify
  3472 the naming context.  Especially note Theory.restore_naming and
  3473 ProofContext.restore_naming to get back to a sane state; note that
  3474 Theory.add_path is no longer sufficient to recover from
  3475 Theory.absolute_path in particular.
  3476 
  3477 * Pure: new flags short_names (default false) and unique_names
  3478 (default true) for controlling output of qualified names.  If
  3479 short_names is set, names are printed unqualified.  If unique_names is
  3480 reset, the name prefix is reduced to the minimum required to achieve
  3481 the original result when interning again, even if there is an overlap
  3482 with earlier declarations.
  3483 
  3484 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3485 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3486 (useful for printing error messages).  INCOMPATIBILITY.
  3487 
  3488 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3489 Theory.theory are now identified, referring to the universal
  3490 Context.theory (see Pure/context.ML).  Actual signature and theory
  3491 content is managed as theory data.  The old code and interfaces were
  3492 spread over many files and structures; the new arrangement introduces
  3493 considerable INCOMPATIBILITY to gain more clarity:
  3494 
  3495   Context -- theory management operations (name, identity, inclusion,
  3496     parents, ancestors, merge, etc.), plus generic theory data;
  3497 
  3498   Sign -- logical signature and syntax operations (declaring consts,
  3499     types, etc.), plus certify/read for common entities;
  3500 
  3501   Theory -- logical theory operations (stating axioms, definitions,
  3502     oracles), plus a copy of logical signature operations (consts,
  3503     types, etc.); also a few basic management operations (Theory.copy,
  3504     Theory.merge, etc.)
  3505 
  3506 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3507 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3508 for convenience -- they merely return the theory.
  3509 
  3510 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3511 
  3512 * Pure: the Isar proof context type is already defined early in Pure
  3513 as Context.proof (note that ProofContext.context and Proof.context are
  3514 aliases, where the latter is the preferred name).  This enables other
  3515 Isabelle components to refer to that type even before Isar is present.
  3516 
  3517 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3518 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3519 any of these kinds.  For example, Sign.intern typeK is now
  3520 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3521 Theory.hide_types.  Also note that former
  3522 Theory.hide_classes/types/consts are now
  3523 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3524 internalize their arguments!  INCOMPATIBILITY.
  3525 
  3526 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3527 datatype thmref (with constructors Name and NameSelection) instead of
  3528 plain string -- INCOMPATIBILITY;
  3529 
  3530 * Pure: cases produced by proof methods specify options, where NONE
  3531 means to remove case bindings -- INCOMPATIBILITY in
  3532 (RAW_)METHOD_CASES.
  3533 
  3534 * Pure: the following operations retrieve axioms or theorems from a
  3535 theory node or theory hierarchy, respectively:
  3536 
  3537   Theory.axioms_of: theory -> (string * term) list
  3538   Theory.all_axioms_of: theory -> (string * term) list
  3539   PureThy.thms_of: theory -> (string * thm) list
  3540   PureThy.all_thms_of: theory -> (string * thm) list
  3541 
  3542 * Pure: print_tac now outputs the goal through the trace channel.
  3543 
  3544 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3545 Reference Toplevel.debug (default false) controls detailed printing
  3546 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3547 controls execution profiling -- set to 1 for time and 2 for space
  3548 (both increase the runtime).
  3549 
  3550 * Isar session: The initial use of ROOT.ML is now always timed,
  3551 i.e. the log will show the actual process times, in contrast to the
  3552 elapsed wall-clock time that the outer shell wrapper produces.
  3553 
  3554 * Simplifier: improved handling of bound variables (nameless
  3555 representation, avoid allocating new strings).  Simprocs that invoke
  3556 the Simplifier recursively should use Simplifier.inherit_bounds to
  3557 avoid local name clashes.  Failure to do so produces warnings
  3558 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3559 for further details.
  3560 
  3561 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3562 bindings for all theorems stored within a given theory; this may help
  3563 in porting non-Isar theories to Isar ones, while keeping ML proof
  3564 scripts for the time being.
  3565 
  3566 * ML operator HTML.with_charset specifies the charset begin used for
  3567 generated HTML files.  For example:
  3568 
  3569   HTML.with_charset "utf-8" use_thy "Hebrew";
  3570   HTML.with_charset "utf-8" use_thy "Chinese";
  3571 
  3572 
  3573 *** System ***
  3574 
  3575 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3576 isabelle, isatool etc.).
  3577 
  3578 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3579 isatool doc, isatool mkdir, display_drafts etc.).
  3580 
  3581 * isatool usedir: option -f allows specification of the ML file to be
  3582 used by Isabelle; default is ROOT.ML.
  3583 
  3584 * New isatool version outputs the version identifier of the Isabelle
  3585 distribution being used.
  3586 
  3587 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3588 (containing Boolean satisfiability problems) into Isabelle/HOL
  3589 theories.
  3590 
  3591 
  3592 
  3593 New in Isabelle2004 (April 2004)
  3594 --------------------------------
  3595 
  3596 *** General ***
  3597 
  3598 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3599   Replaces linorder.ML.
  3600 
  3601 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3602   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3603   (\<a>...\<z>), are now considered normal letters, and can therefore
  3604   be used anywhere where an ASCII letter (a...zA...Z) has until
  3605   now. COMPATIBILITY: This obviously changes the parsing of some
  3606   terms, especially where a symbol has been used as a binder, say
  3607   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3608   as an identifier.  Fix it by inserting a space around former
  3609   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3610   existing theory and ML files.
  3611 
  3612 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3613 
  3614 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3615   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3616   a normal (but invisible) letter. For multiple letter subscripts repeat
  3617   \<^isub> like this: x\<^isub>1\<^isub>2.
  3618 
  3619 * Pure: There are now sub-/superscripts that can span more than one
  3620   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3621   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3622   superscript. The new control characters are not identifier parts.
  3623 
  3624 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3625   content of "..." to the latex file instead of \isacntrl... . The "..."
  3626   may consist of any printable characters excluding the end bracket >.
  3627 
  3628 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3629   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3630   declare constants "final", which prevents their being given a definition
  3631   later.  It is useful for constants whose behaviour is fixed axiomatically
  3632   rather than definitionally, such as the meta-logic connectives.
  3633 
  3634 * Pure: 'instance' now handles general arities with general sorts
  3635   (i.e. intersections of classes),
  3636 
  3637 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3638   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3639   It can be changed to alter the colors/layout of generated pages.
  3640 
  3641 
  3642 *** Isar ***
  3643 
  3644 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3645   cut_tac, subgoal_tac and thin_tac:
  3646   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3647     locales are no longer forced to write Isar proof scripts.
  3648     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3649     emulations.
  3650   - INCOMPATIBILITY: names of variables to be instantiated may no
  3651     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3652     This is consistent with the instantiation attribute "where".
  3653 
  3654 * Attributes "where" and "of":
  3655   - Now take type variables of instantiated theorem into account when reading
  3656     the instantiation string.  This fixes a bug that caused instantiated
  3657     theorems to have too special types in some circumstances.
  3658   - "where" permits explicit instantiations of type variables.
  3659 
  3660 * Calculation commands "moreover" and "also" no longer interfere with
  3661   current facts ("this"), admitting arbitrary combinations with "then"
  3662   and derived forms.
  3663 
  3664 * Locales:
  3665   - Goal statements involving the context element "includes" no longer
  3666     generate theorems with internal delta predicates (those ending on
  3667     "_axioms") in the premise.
  3668     Resolve particular premise with <locale>.intro to obtain old form.
  3669   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3670     specification and "includes" elements in goal statement.
  3671   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3672     [intro?] and [elim?] (respectively) by default.
  3673   - Experimental command for instantiation of locales in proof contexts:
  3674         instantiate <label>[<attrs>]: <loc>
  3675     Instantiates locale <loc> and adds all its theorems to the current context
  3676     taking into account their attributes.  Label and attrs are optional
  3677     modifiers, like in theorem declarations.  If present, names of
  3678     instantiated theorems are qualified with <label>, and the attributes
  3679     <attrs> are applied after any attributes these theorems might have already.
  3680       If the locale has assumptions, a chained fact of the form
  3681     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3682     are derived.  The command does not support old-style locales declared
  3683     with "locale (open)".
  3684       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3685 
  3686 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3687   (Isar) contexts.
  3688 
  3689 
  3690 *** HOL ***
  3691 
  3692 * Proof import: new image HOL4 contains the imported library from
  3693   the HOL4 system with about 2500 theorems. It is imported by
  3694   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3695   can be used like any other Isabelle image.  See
  3696   HOL/Import/HOL/README for more information.
  3697 
  3698 * Simplifier:
  3699   - Much improved handling of linear and partial orders.
  3700     Reasoners for linear and partial orders are set up for type classes
  3701     "linorder" and "order" respectively, and are added to the default simpset
  3702     as solvers.  This means that the simplifier can build transitivity chains
  3703     to solve goals from the assumptions.
  3704   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3705     of blast or auto after simplification become unnecessary because the goal
  3706     is solved by simplification already.
  3707 
  3708 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3709     all proved in axiomatic type classes for semirings, rings and fields.
  3710 
  3711 * Numerics:
  3712   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3713     now formalized using the Ring_and_Field theory mentioned above.
  3714   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3715     than before, because now they are set up once in a generic manner.
  3716   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3717     Look for the general versions in Ring_and_Field (and Power if they concern
  3718     exponentiation).
  3719 
  3720 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3721 
  3722 * Records:
  3723   - Record types are now by default printed with their type abbreviation
  3724     instead of the list of all field types. This can be configured via
  3725     the reference "print_record_type_abbr".
  3726   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3727     (not enabled by default).
  3728   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3729     EX x. x = sel r to True (not enabled by default).
  3730   - Tactic "record_split_simp_tac" to split and simplify records added.
  3731 
  3732 * 'specification' command added, allowing for definition by
  3733   specification.  There is also an 'ax_specification' command that
  3734   introduces the new constants axiomatically.
  3735 
  3736 * arith(_tac) is now able to generate counterexamples for reals as well.
  3737 
  3738 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3739 
  3740 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3741   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3742 
  3743 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3744   matrix theory to linear programming.
  3745 
  3746 * Unions and Intersections:
  3747   The latex output syntax of UN and INT has been changed
  3748   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3749   i.e. the index formulae has become a subscript.
  3750   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3751 
  3752 * Unions and Intersections over Intervals:
  3753   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3754   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3755   like in normal math, and corresponding versions for < and for intersection.
  3756 
  3757 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3758   lexicographic dictonary ordering has been added as "lexord".
  3759 
  3760 * ML: the legacy theory structures Int and List have been removed. They had
  3761   conflicted with ML Basis Library structures having the same names.
  3762 
  3763 * 'refute' command added to search for (finite) countermodels.  Only works
  3764   for a fragment of HOL.  The installation of an external SAT solver is
  3765   highly recommended.  See "HOL/Refute.thy" for details.
  3766 
  3767 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3768   formulae under an assignment of free variables to random values.
  3769   In contrast to 'refute', it can deal with inductive datatypes,
  3770   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3771   for examples.
  3772 
  3773 
  3774 *** HOLCF ***
  3775 
  3776 * Streams now come with concatenation and are part of the HOLCF image
  3777 
  3778 
  3779 
  3780 New in Isabelle2003 (May 2003)
  3781 ------------------------------
  3782 
  3783 *** General ***
  3784 
  3785 * Provers/simplifier:
  3786 
  3787   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3788     Assumptions are now subject to complete mutual simplification,
  3789     not just from left to right. The simplifier now preserves
  3790     the order of assumptions.
  3791 
  3792     Potential INCOMPATIBILITY:
  3793 
  3794     -- simp sometimes diverges where the old version did
  3795        not, e.g. invoking simp on the goal
  3796 
  3797         [| P (f x); y = x; f x = f y |] ==> Q
  3798 
  3799        now gives rise to the infinite reduction sequence
  3800 
  3801         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3802 
  3803        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3804        kind of problem.
  3805 
  3806     -- Tactics combining classical reasoner and simplification (such as auto)
  3807        are also affected by this change, because many of them rely on
  3808        simp. They may sometimes diverge as well or yield a different numbers
  3809        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3810        in case of problems. Sometimes subsequent calls to the classical
  3811        reasoner will fail because a preceeding call to the simplifier too
  3812        eagerly simplified the goal, e.g. deleted redundant premises.
  3813 
  3814   - The simplifier trace now shows the names of the applied rewrite rules
  3815 
  3816   - You can limit the number of recursive invocations of the simplifier
  3817     during conditional rewriting (where the simplifie tries to solve the
  3818     conditions before applying the rewrite rule):
  3819     ML "simp_depth_limit := n"
  3820     where n is an integer. Thus you can force termination where previously
  3821     the simplifier would diverge.
  3822 
  3823   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3824 
  3825   - No longer aborts on failed congruence proof.  Instead, the
  3826     congruence is ignored.
  3827 
  3828 * Pure: New generic framework for extracting programs from constructive
  3829   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3830   as HOL/Extraction for some case studies.
  3831 
  3832 * Pure: The main goal of the proof state is no longer shown by default, only
  3833 the subgoals. This behaviour is controlled by a new flag.
  3834    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3835 (ML: Proof.show_main_goal).
  3836 
  3837 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3838 rules whose conclusion matches subgoal 1:
  3839       PG menu: Isabelle/Isar -> Show me -> matching rules
  3840 The rules are ordered by how closely they match the subgoal.
  3841 In particular, rules that solve a subgoal outright are displayed first
  3842 (or rather last, the way they are printed).
  3843 (ML: ProofGeneral.print_intros())
  3844 
  3845 * Pure: New flag trace_unify_fail causes unification to print
  3846 diagnostic information (PG: in trace buffer) when it fails. This is
  3847 useful for figuring out why single step proofs like rule, erule or
  3848 assumption failed.
  3849 
  3850 * Pure: Locale specifications now produce predicate definitions
  3851 according to the body of text (covering assumptions modulo local
  3852 definitions); predicate "loc_axioms" covers newly introduced text,
  3853 while "loc" is cumulative wrt. all included locale expressions; the
  3854 latter view is presented only on export into the global theory
  3855 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3856 on the old view without predicates;
  3857 
  3858 * Pure: predefined locales "var" and "struct" are useful for sharing
  3859 parameters (as in CASL, for example); just specify something like
  3860 ``var x + var y + struct M'' as import;
  3861 
  3862 * Pure: improved thms_containing: proper indexing of facts instead of
  3863 raw theorems; check validity of results wrt. current name space;
  3864 include local facts of proof configuration (also covers active
  3865 locales), cover fixed variables in index; may use "_" in term
  3866 specification; an optional limit for the number of printed facts may
  3867 be given (the default is 40);
  3868 
  3869 * Pure: disallow duplicate fact bindings within new-style theory files
  3870 (batch-mode only);
  3871 
  3872 * Provers: improved induct method: assumptions introduced by case
  3873 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3874 the goal statement); "foo" still refers to all facts collectively;
  3875 
  3876 * Provers: the function blast.overloaded has been removed: all constants
  3877 are regarded as potentially overloaded, which improves robustness in exchange
  3878 for slight decrease in efficiency;
  3879 
  3880 * Provers/linorder: New generic prover for transitivity reasoning over
  3881 linear orders.  Note: this prover is not efficient!
  3882 
  3883 * Isar: preview of problems to finish 'show' now produce an error
  3884 rather than just a warning (in interactive mode);
  3885 
  3886 
  3887 *** HOL ***
  3888 
  3889 * arith(_tac)
  3890 
  3891  - Produces a counter example if it cannot prove a goal.
  3892    Note that the counter example may be spurious if the goal is not a formula
  3893    of quantifier-free linear arithmetic.
  3894    In ProofGeneral the counter example appears in the trace buffer.
  3895 
  3896  - Knows about div k and mod k where k is a numeral of type nat or int.
  3897 
  3898  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3899    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3900    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3901 
  3902 * simp's arithmetic capabilities have been enhanced a bit: it now
  3903 takes ~= in premises into account (by performing a case split);
  3904 
  3905 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3906 are distributed over a sum of terms;
  3907 
  3908 * New tactic "trans_tac" and method "trans" instantiate
  3909 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3910 "<=", "<" and "=").
  3911 
  3912 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3913 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3914 
  3915 * 'typedef' command has new option "open" to suppress the set
  3916 definition;
  3917 
  3918 * functions Min and Max on finite sets have been introduced (theory
  3919 Finite_Set);
  3920 
  3921 * attribute [symmetric] now works for relations as well; it turns
  3922 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3923 
  3924 * induct over a !!-quantified statement (say !!x1..xn):
  3925   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3926 
  3927 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3928 %x. None. Warning: empty_def now refers to the previously hidden definition
  3929 of the empty set.
  3930 
  3931 * Algebra: formalization of classical algebra.  Intended as base for
  3932 any algebraic development in Isabelle.  Currently covers group theory
  3933 (up to Sylow's theorem) and ring theory (Universal Property of
  3934 Univariate Polynomials).  Contributions welcome;
  3935 
  3936 * GroupTheory: deleted, since its material has been moved to Algebra;
  3937 
  3938 * Complex: new directory of the complex numbers with numeric constants,
  3939 nonstandard complex numbers, and some complex analysis, standard and
  3940 nonstandard (Jacques Fleuriot);
  3941 
  3942 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3943 
  3944 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3945 Fleuriot);
  3946 
  3947 * Real/HahnBanach: updated and adapted to locales;
  3948 
  3949 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3950 Gray and Kramer);
  3951 
  3952 * UNITY: added the Meier-Sanders theory of progress sets;
  3953 
  3954 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3955 as abstract algorithms, instantiated to the JVM;
  3956 
  3957 * Bali: Java source language formalization. Type system, operational
  3958 semantics, axiomatic semantics. Supported language features:
  3959 classes, interfaces, objects,virtual methods, static methods,
  3960 static/instance fields, arrays, access modifiers, definite
  3961 assignment, exceptions.
  3962 
  3963 
  3964 *** ZF ***
  3965 
  3966 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3967 universe, etc.);
  3968 
  3969 * Main ZF: virtually all theories converted to new-style format;
  3970 
  3971 
  3972 *** ML ***
  3973 
  3974 * Pure: Tactic.prove provides sane interface for internal proofs;
  3975 omits the infamous "standard" operation, so this is more appropriate
  3976 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3977 
  3978 * Pure: improved error reporting of simprocs;
  3979 
  3980 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3981 up simprocs;
  3982 
  3983 
  3984 *** Document preparation ***
  3985 
  3986 * uses \par instead of \\ for line breaks in theory text. This may
  3987 shift some page breaks in large documents. To get the old behaviour
  3988 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3989 
  3990 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3991 other packages
  3992 
  3993 * \<euro> now needs package babel/greek instead of marvosym (which
  3994 broke \Rightarrow)
  3995 
  3996 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3997 textcomp package)
  3998 
  3999 
  4000 
  4001 New in Isabelle2002 (March 2002)
  4002 --------------------------------
  4003 
  4004 *** Document preparation ***
  4005 
  4006 * greatly simplified document preparation setup, including more
  4007 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4008 instructive isatool mkdir; users should basically be able to get
  4009 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4010 users may run a separate document processing stage manually like this:
  4011 "isatool usedir -D output HOL Test && isatool document Test/output";
  4012 
  4013 * theory dependency graph may now be incorporated into documents;
  4014 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4015 with \includegraphics of LaTeX;
  4016 
  4017 * proper spacing of consecutive markup elements, especially text
  4018 blocks after section headings;
  4019 
  4020 * support bold style (for single symbols only), input syntax is like
  4021 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4022 
  4023 * \<bullet> is now output as bold \cdot by default, which looks much
  4024 better in printed text;
  4025 
  4026 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4027 note that these symbols are currently unavailable in Proof General /
  4028 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4029 
  4030 * isatool latex no longer depends on changed TEXINPUTS, instead
  4031 isatool document copies the Isabelle style files to the target
  4032 location;
  4033 
  4034 
  4035 *** Isar ***
  4036 
  4037 * Pure/Provers: improved proof by cases and induction;
  4038   - 'case' command admits impromptu naming of parameters (such as
  4039     "case (Suc n)");
  4040   - 'induct' method divinates rule instantiation from the inductive
  4041     claim; no longer requires excessive ?P bindings for proper
  4042     instantiation of cases;
  4043   - 'induct' method properly enumerates all possibilities of set/type
  4044     rules; as a consequence facts may be also passed through *type*
  4045     rules without further ado;
  4046   - 'induct' method now derives symbolic cases from the *rulified*
  4047     rule (before it used to rulify cases stemming from the internal
  4048     atomized version); this means that the context of a non-atomic
  4049     statement becomes is included in the hypothesis, avoiding the
  4050     slightly cumbersome show "PROP ?case" form;
  4051   - 'induct' may now use elim-style induction rules without chaining
  4052     facts, using ``missing'' premises from the goal state; this allows
  4053     rules stemming from inductive sets to be applied in unstructured
  4054     scripts, while still benefitting from proper handling of non-atomic
  4055     statements; NB: major inductive premises need to be put first, all
  4056     the rest of the goal is passed through the induction;
  4057   - 'induct' proper support for mutual induction involving non-atomic
  4058     rule statements (uses the new concept of simultaneous goals, see
  4059     below);
  4060   - append all possible rule selections, but only use the first
  4061     success (no backtracking);
  4062   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4063   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4064   - added 'print_induct_rules' (covered by help item in recent Proof
  4065     General versions);
  4066   - moved induct/cases attributes to Pure, methods to Provers;
  4067   - generic method setup instantiated for FOL and HOL;
  4068 
  4069 * Pure: support multiple simultaneous goal statements, for example
  4070 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4071 meta-level mechanism, this acts as if several individual goals had
  4072 been stated separately; in particular common proof methods need to be
  4073 repeated in order to cover all claims; note that a single elimination
  4074 step is *not* sufficient to establish the two conjunctions, so this
  4075 fails:
  4076 
  4077   assume "A & B" then have A and B ..   (*".." fails*)
  4078 
  4079 better use "obtain" in situations as above; alternative refer to
  4080 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4081 
  4082 * Pure: proper integration with ``locales''; unlike the original
  4083 version by Florian Kammller, Isar locales package high-level proof
  4084 contexts rather than raw logical ones (e.g. we admit to include
  4085 attributes everywhere); operations on locales include merge and
  4086 rename; support for implicit arguments (``structures''); simultaneous
  4087 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4088 some examples;
  4089 
  4090 * Pure: the following commands have been ``localized'', supporting a
  4091 target locale specification "(in name)": 'lemma', 'theorem',
  4092 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4093 stored both within the locale and at the theory level (exported and
  4094 qualified by the locale name);
  4095 
  4096 * Pure: theory goals may now be specified in ``long'' form, with
  4097 ad-hoc contexts consisting of arbitrary locale elements. for example
  4098 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4099 definitions may be given, too); the result is a meta-level rule with
  4100 the context elements being discharged in the obvious way;
  4101 
  4102 * Pure: new proof command 'using' allows to augment currently used
  4103 facts after a goal statement ('using' is syntactically analogous to
  4104 'apply', but acts on the goal's facts only); this allows chained facts
  4105 to be separated into parts given before and after a claim, as in
  4106 ``from a and b have C using d and e <proof>'';
  4107 
  4108 * Pure: renamed "antecedent" case to "rule_context";
  4109 
  4110 * Pure: new 'judgment' command records explicit information about the
  4111 object-logic embedding (used by several tools internally); no longer
  4112 use hard-wired "Trueprop";
  4113 
  4114 * Pure: added 'corollary' command;
  4115 
  4116 * Pure: fixed 'token_translation' command;
  4117 
  4118 * Pure: removed obsolete 'exported' attribute;
  4119 
  4120 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4121 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4122 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4123 
  4124 * Pure: method 'atomize' presents local goal premises as object-level
  4125 statements (atomic meta-level propositions); setup controlled via
  4126 rewrite rules declarations of 'atomize' attribute; example
  4127 application: 'induct' method with proper rule statements in improper
  4128 proof *scripts*;
  4129 
  4130 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4131 now consider the syntactic context of assumptions, giving a better
  4132 chance to get type-inference of the arguments right (this is
  4133 especially important for locales);
  4134 
  4135 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4136 mode;
  4137 
  4138 * Pure/obtain: the formal conclusion "thesis", being marked as
  4139 ``internal'', may no longer be reference directly in the text;
  4140 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4141 situations;
  4142 
  4143 * Pure: generic 'sym' attribute which declares a rule both as pure
  4144 'elim?' and for the 'symmetric' operation;
  4145 
  4146 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4147 text; the fixed correlation with particular command syntax has been
  4148 discontinued;
  4149 
  4150 * Pure: new method 'rules' is particularly well-suited for proof
  4151 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4152 but often produces more compact proof terms with less detours;
  4153 
  4154 * Pure/Provers/classical: simplified integration with pure rule
  4155 attributes and methods; the classical "intro?/elim?/dest?"
  4156 declarations coincide with the pure ones; the "rule" method no longer
  4157 includes classically swapped intros; "intro" and "elim" methods no
  4158 longer pick rules from the context; also got rid of ML declarations
  4159 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4160 INCOMPATIBILITY;
  4161 
  4162 * Provers/classical: attribute 'swapped' produces classical inversions
  4163 of introduction rules;
  4164 
  4165 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4166 rules instead of full simplifier context; 'iff' attribute handles
  4167 conditional rules;
  4168 
  4169 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4170 
  4171 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4172 "(permissive)" option to recover old behavior;
  4173 
  4174 * HOL: 'inductive' no longer features separate (collective) attributes
  4175 for 'intros' (was found too confusing);
  4176 
  4177 * HOL: properly declared induction rules less_induct and
  4178 wf_induct_rule;
  4179 
  4180 
  4181 *** HOL ***
  4182 
  4183 * HOL: moved over to sane numeral syntax; the new policy is as
  4184 follows:
  4185 
  4186   - 0 and 1 are polymorphic constants, which are defined on any
  4187   numeric type (nat, int, real etc.);
  4188 
  4189   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4190   binary representation internally;
  4191 
  4192   - type nat has special constructor Suc, and generally prefers Suc 0
  4193   over 1::nat and Suc (Suc 0) over 2::nat;
  4194 
  4195 This change may cause significant problems of INCOMPATIBILITY; here
  4196 are some hints on converting existing sources:
  4197 
  4198   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4199   entities, so expressions involving "-" (unary or binary minus) need
  4200   to be spaced properly;
  4201 
  4202   - existing occurrences of "1" may need to be constraint "1::nat" or
  4203   even replaced by Suc 0; similar for old "2";
  4204 
  4205   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4206 
  4207   - remove all special provisions on numerals in proofs;
  4208 
  4209 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4210 representation (depends on bin_arith_simps in the default context);
  4211 
  4212 * HOL: symbolic syntax for x^2 (numeral 2);
  4213 
  4214 * HOL: the class of all HOL types is now called "type" rather than
  4215 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4216 in axclass/classes, instance/arities, and (usually rare) occurrences
  4217 in typings (of consts etc.); internally the class is called
  4218 "HOL.type", ML programs should refer to HOLogic.typeS;
  4219 
  4220 * HOL/record package improvements:
  4221   - new derived operations "fields" to build a partial record section,
  4222     "extend" to promote a fixed record to a record scheme, and
  4223     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4224     declared as simp by default;
  4225   - shared operations ("more", "fields", etc.) now need to be always
  4226     qualified) --- potential INCOMPATIBILITY;
  4227   - removed "make_scheme" operations (use "make" with "extend") --
  4228     INCOMPATIBILITY;
  4229   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4230   - provides cases/induct rules for use with corresponding Isar
  4231     methods (for concrete records, record schemes, concrete more
  4232     parts, and schematic more parts -- in that order);
  4233   - internal definitions directly based on a light-weight abstract
  4234     theory of product types over typedef rather than datatype;
  4235 
  4236 * HOL: generic code generator for generating executable ML code from
  4237 specifications; specific support for HOL constructs such as inductive
  4238 datatypes and sets, as well as recursive functions; can be invoked
  4239 via 'generate_code' theory section;
  4240 
  4241 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4242 
  4243 * HOL: consolidated and renamed several theories.  In particular:
  4244         Ord.thy has been absorbed into HOL.thy
  4245         String.thy has been absorbed into List.thy
  4246 
  4247 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4248 (beware of argument permutation!);
  4249 
  4250 * HOL: linorder_less_split superseded by linorder_cases;
  4251 
  4252 * HOL/List: "nodups" renamed to "distinct";
  4253 
  4254 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4255 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4256   - Ex_def has changed, now need to use some_eq_ex
  4257 
  4258 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4259 in this (rare) case use:
  4260 
  4261   delSWrapper "split_all_tac"
  4262   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4263 
  4264 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4265 MAY FAIL;
  4266 
  4267 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4268 Isabelle's type classes, ^ on functions and relations has too general
  4269 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4270 necessary to attach explicit type constraints;
  4271 
  4272 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4273 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4274 renamed accordingly (eg "compI" -> "rel_compI").
  4275 
  4276 * HOL: syntax translations now work properly with numerals and records
  4277 expressions;
  4278 
  4279 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4280 of "lam" -- INCOMPATIBILITY;
  4281 
  4282 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4283 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4284 renamed "Product_Type.unit";
  4285 
  4286 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4287 
  4288 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4289 the "cases" method);
  4290 
  4291 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4292 Florian Kammller);
  4293 
  4294 * HOL/IMP: updated and converted to new-style theory format; several
  4295 parts turned into readable document, with proper Isar proof texts and
  4296 some explanations (by Gerwin Klein);
  4297 
  4298 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4299 
  4300 * HOL-Hyperreal is now a logic image;
  4301 
  4302 
  4303 *** HOLCF ***
  4304 
  4305 * Isar: consts/constdefs supports mixfix syntax for continuous
  4306 operations;
  4307 
  4308 * Isar: domain package adapted to new-style theory format, e.g. see
  4309 HOLCF/ex/Dnat.thy;
  4310 
  4311 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4312 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4313 lift.induct_tac, always use UU instead of Undef;
  4314 
  4315 * HOLCF/IMP: updated and converted to new-style theory;
  4316 
  4317 
  4318 *** ZF ***
  4319 
  4320 * Isar: proper integration of logic-specific tools and packages,
  4321 including theory commands '(co)inductive', '(co)datatype',
  4322 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4323 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4324 
  4325 * theory Main no longer includes AC; for the Axiom of Choice, base
  4326 your theory on Main_ZFC;
  4327 
  4328 * the integer library now covers quotients and remainders, with many
  4329 laws relating division to addition, multiplication, etc.;
  4330 
  4331 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4332 typeless version of the formalism;
  4333 
  4334 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4335 format;
  4336 
  4337 * ZF/Induct: new directory for examples of inductive definitions,
  4338 including theory Multiset for multiset orderings; converted to
  4339 new-style theory format;
  4340 
  4341 * ZF: many new theorems about lists, ordinals, etc.;
  4342 
  4343 
  4344 *** General ***
  4345 
  4346 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4347 variable proof controls level of detail: 0 = no proofs (only oracle
  4348 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4349 also ref manual for further ML interfaces;
  4350 
  4351 * Pure/axclass: removed obsolete ML interface
  4352 goal_subclass/goal_arity;
  4353 
  4354 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4355 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4356 separate tokens, so expressions involving minus need to be spaced
  4357 properly;
  4358 
  4359 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4360 rather than "infixl" or "infixr";
  4361 
  4362 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4363 sort constraint specifications in type inference; e.g. "x::_::foo"
  4364 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4365 type variable);
  4366 
  4367 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4368 control output of nested => (types); the default behavior is
  4369 "type_brackets";
  4370 
  4371 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4372 tokens into AST constants;
  4373 
  4374 * Pure/syntax: prefer later declarations of translations and print
  4375 translation functions; potential INCOMPATIBILITY: need to reverse
  4376 multiple declarations for same syntax element constant;
  4377 
  4378 * Pure/show_hyps reset by default (in accordance to existing Isar
  4379 practice);
  4380 
  4381 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4382 addSafter;
  4383 
  4384 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4385 as well;
  4386 
  4387 * system: tested support for MacOS X; should be able to get Isabelle +
  4388 Proof General to work in a plain Terminal after installing Poly/ML
  4389 (e.g. from the Isabelle distribution area) and GNU bash alone
  4390 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4391 support requires further installations, e.g. from
  4392 http://fink.sourceforge.net/);
  4393 
  4394 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4395 
  4396 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4397 of 40 MB), cf. ML_OPTIONS;
  4398 
  4399 * system: Proof General keywords specification is now part of the
  4400 Isabelle distribution (see etc/isar-keywords.el);
  4401 
  4402 * system: support for persistent Proof General sessions (refrain from
  4403 outdating all loaded theories on startup); user may create writable
  4404 logic images like this: ``isabelle -q HOL Test'';
  4405 
  4406 * system: smart selection of Isabelle process versus Isabelle
  4407 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4408 run both "isabelle" and "Isabelle" even if file names are badly
  4409 damaged (executable inspects the case of the first letter of its own
  4410 name); added separate "isabelle-process" and "isabelle-interface";
  4411 
  4412 * system: refrain from any attempt at filtering input streams; no
  4413 longer support ``8bit'' encoding of old isabelle font, instead proper
  4414 iso-latin characters may now be used; the related isatools
  4415 "symbolinput" and "nonascii" have disappeared as well;
  4416 
  4417 * system: removed old "xterm" interface (the print modes "xterm" and
  4418 "xterm_color" are still available for direct use in a suitable
  4419 terminal);
  4420 
  4421 
  4422 
  4423 New in Isabelle99-2 (February 2001)
  4424 -----------------------------------
  4425 
  4426 *** Overview of INCOMPATIBILITIES ***
  4427 
  4428 * HOL: please note that theories in the Library and elsewhere often use the
  4429 new-style (Isar) format; to refer to their theorems in an ML script you must
  4430 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4431 
  4432 * HOL: inductive package no longer splits induction rule aggressively,
  4433 but only as far as specified by the introductions given; the old
  4434 format may be recovered via ML function complete_split_rule or attribute
  4435 'split_rule (complete)';
  4436 
  4437 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4438 gfp_Tarski to gfp_unfold;
  4439 
  4440 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4441 
  4442 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4443 relation); infix "^^" has been renamed "``"; infix "``" has been
  4444 renamed "`"; "univalent" has been renamed "single_valued";
  4445 
  4446 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4447 operation;
  4448 
  4449 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4450 
  4451 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4452 
  4453 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4454 consequence, it is no longer monotonic wrt. the local goal context
  4455 (which is now passed through the inductive cases);
  4456 
  4457 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4458 \<gg> to \<ggreater>;
  4459 
  4460 
  4461 *** Document preparation ***
  4462 
  4463 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4464 available: are "it" for near math-mode best-style output, "sl" for
  4465 slanted text style, and "tt" for plain type-writer; if no
  4466 \isabellestyle command is given, output is according to slanted
  4467 type-writer);
  4468 
  4469 * support sub/super scripts (for single symbols only), input syntax is
  4470 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4471 
  4472 * some more standard symbols; see Appendix A of the system manual for
  4473 the complete list of symbols defined in isabellesym.sty;
  4474 
  4475 * improved isabelle style files; more abstract symbol implementation
  4476 (should now use \isamath{...} and \isatext{...} in custom symbol
  4477 definitions);
  4478 
  4479 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4480 state; Note that presentation of goal states does not conform to
  4481 actual human-readable proof documents.  Please do not include goal
  4482 states into document output unless you really know what you are doing!
  4483 
  4484 * proper indentation of antiquoted output with proportional LaTeX
  4485 fonts;
  4486 
  4487 * no_document ML operator temporarily disables LaTeX document
  4488 generation;
  4489 
  4490 * isatool unsymbolize tunes sources for plain ASCII communication;
  4491 
  4492 
  4493 *** Isar ***
  4494 
  4495 * Pure: Isar now suffers initial goal statements to contain unbound
  4496 schematic variables (this does not conform to actual readable proof
  4497 documents, due to unpredictable outcome and non-compositional proof
  4498 checking); users who know what they are doing may use schematic goals
  4499 for Prolog-style synthesis of proven results;
  4500 
  4501 * Pure: assumption method (an implicit finishing) now handles actual
  4502 rules as well;
  4503 
  4504 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4505 initial goal, declare "that" only as Pure intro (only for single
  4506 steps); the "that" rule assumption may now be involved in implicit
  4507 finishing, thus ".." becomes a feasible for trivial obtains;
  4508 
  4509 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4510 instance proofs may be performed by "..";
  4511 
  4512 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4513 statements as well;
  4514 
  4515 * Pure: more robust selection of calculational rules;
  4516 
  4517 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4518 rule (as well as the assumption rule);
  4519 
  4520 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4521 lemmas, using the graph browser tool;
  4522 
  4523 * Pure: predict failure of "show" in interactive mode;
  4524 
  4525 * Pure: 'thms_containing' now takes actual terms as arguments;
  4526 
  4527 * HOL: improved method 'induct' --- now handles non-atomic goals
  4528 (potential INCOMPATIBILITY); tuned error handling;
  4529 
  4530 * HOL: cases and induct rules now provide explicit hints about the
  4531 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4532 any remaining facts are inserted into the goal verbatim;
  4533 
  4534 * HOL: local contexts (aka cases) may now contain term bindings as
  4535 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4536 the result to be shown in each case;
  4537 
  4538 * HOL: added 'recdef_tc' command;
  4539 
  4540 * isatool convert assists in eliminating legacy ML scripts;
  4541 
  4542 
  4543 *** HOL ***
  4544 
  4545 * HOL/Library: a collection of generic theories to be used together
  4546 with main HOL; the theory loader path already includes this directory
  4547 by default; the following existing theories have been moved here:
  4548 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4549 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4550 
  4551 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4552 modelling and verification task performed in Isabelle/HOL +
  4553 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4554 
  4555 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4556 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4557 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4558 'domain', this makes the theory consistent with mathematical
  4559 literature;
  4560 
  4561 * HOL basics: added overloaded operations "inverse" and "divide"
  4562 (infix "/"), syntax for generic "abs" operation, generic summation
  4563 operator \<Sum>;
  4564 
  4565 * HOL/typedef: simplified package, provide more useful rules (see also
  4566 HOL/subset.thy);
  4567 
  4568 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4569 now expressed as a proper nested rule (old-style tactic scripts may
  4570 require atomize_strip_tac to cope with non-atomic premises);
  4571 
  4572 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4573 to "split_conv" (old name still available for compatibility);
  4574 
  4575 * HOL: improved concrete syntax for strings (e.g. allows translation
  4576 rules with string literals);
  4577 
  4578 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4579  and Fleuriot's mechanization of analysis, including the transcendental
  4580  functions for the reals;
  4581 
  4582 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4583 
  4584 
  4585 *** CTT ***
  4586 
  4587 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4588 "lam" is displayed as TWO lambda-symbols
  4589 
  4590 * CTT: theory Main now available, containing everything (that is, Bool
  4591 and Arith);
  4592 
  4593 
  4594 *** General ***
  4595 
  4596 * Pure: the Simplifier has been implemented properly as a derived rule
  4597 outside of the actual kernel (at last!); the overall performance
  4598 penalty in practical applications is about 50%, while reliability of
  4599 the Isabelle inference kernel has been greatly improved;
  4600 
  4601 * print modes "brackets" and "no_brackets" control output of nested =>
  4602 (types) and ==> (props); the default behaviour is "brackets";
  4603 
  4604 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4605 as assumptions as well;
  4606 
  4607 * system: support Poly/ML 4.0;
  4608 
  4609 * system: isatool install handles KDE version 1 or 2;
  4610 
  4611 
  4612 
  4613 New in Isabelle99-1 (October 2000)
  4614 ----------------------------------
  4615 
  4616 *** Overview of INCOMPATIBILITIES ***
  4617 
  4618 * HOL: simplification of natural numbers is much changed; to partly
  4619 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4620 issue the following ML commands:
  4621 
  4622   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4623   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4624 
  4625 * HOL: simplification no longer dives into case-expressions; this is
  4626 controlled by "t.weak_case_cong" for each datatype t;
  4627 
  4628 * HOL: nat_less_induct renamed to less_induct;
  4629 
  4630 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4631 fixsome to patch .thy and .ML sources automatically;
  4632 
  4633   select_equality  -> some_equality
  4634   select_eq_Ex     -> some_eq_ex
  4635   selectI2EX       -> someI2_ex
  4636   selectI2         -> someI2
  4637   selectI          -> someI
  4638   select1_equality -> some1_equality
  4639   Eps_sym_eq       -> some_sym_eq_trivial
  4640   Eps_eq           -> some_eq_trivial
  4641 
  4642 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4643 
  4644 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4645 instead);
  4646 
  4647 * HOL: the recursion equations generated by 'recdef' are now called
  4648 f.simps instead of f.rules;
  4649 
  4650 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4651 
  4652 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4653 sometimes be needed;
  4654 
  4655 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4656 
  4657 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4658 
  4659 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4660 product is now "<*>" instead of "Times"; the lexicographic product is
  4661 now "<*lex*>" instead of "**";
  4662 
  4663 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4664 of main HOL, but was unused); better use HOL's datatype package;
  4665 
  4666 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4667 the old syntax may be recovered as follows:
  4668 
  4669   syntax (symbols)
  4670     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4671       (infixl "\\<oplus>" 100)
  4672 
  4673 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4674 
  4675 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4676 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4677 internally;
  4678 
  4679 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4680 changed from A/r to A//r;
  4681 
  4682 * ZF: new treatment of arithmetic (nat & int) may break some old
  4683 proofs;
  4684 
  4685 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4686 rulify -> rule_format, elimify -> elim_format, ...);
  4687 
  4688 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4689 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4690 should have to change intro!! to intro? only); replaced "delrule" by
  4691 "rule del";
  4692 
  4693 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4694 
  4695 * Provers: strengthened force_tac by using new first_best_tac;
  4696 
  4697 * LaTeX document preparation: several changes of isabelle.sty (see
  4698 lib/texinputs);
  4699 
  4700 
  4701 *** Document preparation ***
  4702 
  4703 * formal comments (text blocks etc.) in new-style theories may now
  4704 contain antiquotations of thm/prop/term/typ/text to be presented
  4705 according to latex print mode; concrete syntax is like this:
  4706 @{term[show_types] "f(x) = a + x"};
  4707 
  4708 * isatool mkdir provides easy setup of Isabelle session directories,
  4709 including proper document sources;
  4710 
  4711 * generated LaTeX sources are now deleted after successful run
  4712 (isatool document -c); may retain a copy somewhere else via -D option
  4713 of isatool usedir;
  4714 
  4715 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4716 style files, achieving self-contained LaTeX sources and simplifying
  4717 LaTeX debugging;
  4718 
  4719 * old-style theories now produce (crude) LaTeX output as well;
  4720 
  4721 * browser info session directories are now self-contained (may be put
  4722 on WWW server seperately); improved graphs of nested sessions; removed
  4723 graph for 'all sessions';
  4724 
  4725 * several improvements in isabelle style files; \isabellestyle{it}
  4726 produces fake math mode output; \isamarkupheader is now \section by
  4727 default; see lib/texinputs/isabelle.sty etc.;
  4728 
  4729 
  4730 *** Isar ***
  4731 
  4732 * Isar/Pure: local results and corresponding term bindings are now
  4733 subject to Hindley-Milner polymorphism (similar to ML); this
  4734 accommodates incremental type-inference very nicely;
  4735 
  4736 * Isar/Pure: new derived language element 'obtain' supports
  4737 generalized existence reasoning;
  4738 
  4739 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4740 support accumulation of results, without applying any rules yet;
  4741 useful to collect intermediate results without explicit name
  4742 references, and for use with transitivity rules with more than 2
  4743 premises;
  4744 
  4745 * Isar/Pure: scalable support for case-analysis type proofs: new
  4746 'case' language element refers to local contexts symbolically, as
  4747 produced by certain proof methods; internally, case names are attached
  4748 to theorems as "tags";
  4749 
  4750 * Isar/Pure: theory command 'hide' removes declarations from
  4751 class/type/const name spaces;
  4752 
  4753 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4754 indicate potential overloading;
  4755 
  4756 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4757 
  4758 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4759 "{a,b,c}" instead of {a,b,c};
  4760 
  4761 * Isar/Pure now provides its own version of intro/elim/dest
  4762 attributes; useful for building new logics, but beware of confusion
  4763 with the version in Provers/classical;
  4764 
  4765 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4766 case name 'antecedent';
  4767 
  4768 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4769 to the current context is now done automatically);
  4770 
  4771 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4772 for definining proof methods in ML;
  4773 
  4774 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4775 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4776 most cases, one should have to change intro!! to intro? only);
  4777 replaced "delrule" by "rule del";
  4778 
  4779 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4780 'symmetric' attribute (the latter supercedes [RS sym]);
  4781 
  4782 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4783 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4784 well (including splits);
  4785 
  4786 * Isar/Provers: Simplifier and Classical methods now support all kind
  4787 of modifiers used in the past, including 'cong', 'iff', etc.
  4788 
  4789 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4790 of Simplifier and Classical reasoner);
  4791 
  4792 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4793 now support named cases; major packages (inductive, datatype, primrec,
  4794 recdef) support case names and properly name parameters;
  4795 
  4796 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4797 monotonicity conditions are extracted to be proven at end of
  4798 calculations;
  4799 
  4800 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4801 method anyway;
  4802 
  4803 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4804 split_if split_if_asm; datatype package provides theorems foo.splits =
  4805 foo.split foo.split_asm for each datatype;
  4806 
  4807 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4808 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4809 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4810 use "(cases (simplified))" method in proper proof texts);
  4811 
  4812 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4813 
  4814 * Isar: names of theorems etc. may be natural numbers as well;
  4815 
  4816 * Isar: 'pr' command: optional arguments for goals_limit and
  4817 ProofContext.prems_limit; no longer prints theory contexts, but only
  4818 proof states;
  4819 
  4820 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4821 additional print modes to be specified; e.g. "pr(latex)" will print
  4822 proof state according to the Isabelle LaTeX style;
  4823 
  4824 * Isar: improved support for emulating tactic scripts, including proof
  4825 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4826 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4827 (for HOL datatypes);
  4828 
  4829 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4830 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4831 'proof method scripts' have to be in depth-first order;
  4832 
  4833 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4834 
  4835 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4836 should instead use individual commands for printing items
  4837 (print_commands, print_methods etc.);
  4838 
  4839 * Isar: added 'nothing' --- the empty list of theorems;
  4840 
  4841 
  4842 *** HOL ***
  4843 
  4844 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4845 corresponding virtual machine and a specification of its bytecode
  4846 verifier and a lightweight bytecode verifier, including proofs of
  4847 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4848 Cornelia Pusch (see also the homepage of project Bali at
  4849 http://isabelle.in.tum.de/Bali/);
  4850 
  4851 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4852 Clemens Ballarin;
  4853 
  4854 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4855 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4856 Rasmussen;
  4857 
  4858 * HOL/Lattice: fundamental concepts of lattice theory and order
  4859 structures, including duals, properties of bounds versus algebraic
  4860 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4861 Theorem for complete lattices etc.; may also serve as a demonstration
  4862 for abstract algebraic reasoning using axiomatic type classes, and
  4863 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4864 
  4865 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4866 von Oheimb;
  4867 
  4868 * HOL/IMPP: extension of IMP with local variables and mutually
  4869 recursive procedures, by David von Oheimb;
  4870 
  4871 * HOL/Lambda: converted into new-style theory and document;
  4872 
  4873 * HOL/ex/Multiquote: example of multiple nested quotations and
  4874 anti-quotations -- basically a generalized version of de-Bruijn
  4875 representation; very useful in avoiding lifting of operations;
  4876 
  4877 * HOL/record: added general record equality rule to simpset; fixed
  4878 select-update simplification procedure to handle extended records as
  4879 well; admit "r" as field name;
  4880 
  4881 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4882 other numeric types and also as the identity of groups, rings, etc.;
  4883 
  4884 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4885 Types nat and int belong to this axclass;
  4886 
  4887 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4888    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4889    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4890   two terms #m*u and #n*u are replaced by #(m+n)*u
  4891     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4892   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4893     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4894 
  4895 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4896 powerful prover for predicate logic but knows nothing of clasets; see
  4897 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4898 
  4899 * HOL: new version of "case_tac" subsumes both boolean case split and
  4900 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4901 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4902 
  4903 * HOL: simplification no longer dives into case-expressions: only the
  4904 selector expression is simplified, but not the remaining arms; to
  4905 enable full simplification of case-expressions for datatype t, you may
  4906 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4907 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4908 
  4909 * HOL/recdef: the recursion equations generated by 'recdef' for
  4910 function 'f' are now called f.simps instead of f.rules; if all
  4911 termination conditions are proved automatically, these simplification
  4912 rules are added to the simpset, as in primrec; rules may be named
  4913 individually as well, resulting in a separate list of theorems for
  4914 each equation;
  4915 
  4916 * HOL/While is a new theory that provides a while-combinator. It
  4917 permits the definition of tail-recursive functions without the
  4918 provision of a termination measure. The latter is necessary once the
  4919 invariant proof rule for while is applied.
  4920 
  4921 * HOL: new (overloaded) notation for the set of elements below/above
  4922 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4923 
  4924 * HOL: theorems impI, allI, ballI bound as "strip";
  4925 
  4926 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4927 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4928 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4929 
  4930 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4931 
  4932 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4933 main HOL, but was unused);
  4934 
  4935 * HOL: fewer consts declared as global (e.g. have to refer to
  4936 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4937 
  4938 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4939 in case of overlap with user translations (e.g. judgements over
  4940 tuples); (note that the underlying logical represenation is still
  4941 bogus);
  4942 
  4943 
  4944 *** ZF ***
  4945 
  4946 * ZF: simplification automatically cancels common terms in arithmetic
  4947 expressions over nat and int;
  4948 
  4949 * ZF: new treatment of nat to minimize type-checking: all operators
  4950 coerce their operands to a natural number using the function natify,
  4951 making the algebraic laws unconditional;
  4952 
  4953 * ZF: as above, for int: operators coerce their operands to an integer
  4954 using the function intify;
  4955 
  4956 * ZF: the integer library now contains many of the usual laws for the
  4957 orderings, including $<=, and monotonicity laws for $+ and $*;
  4958 
  4959 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4960 simplification;
  4961 
  4962 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4963 to the simplifier and classical reasoner simultaneously;
  4964 
  4965 
  4966 *** General ***
  4967 
  4968 * Provers: blast_tac now handles actual object-logic rules as
  4969 assumptions; note that auto_tac uses blast_tac internally as well;
  4970 
  4971 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4972 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4973 
  4974 * Provers: delrules now handles destruct rules as well (no longer need
  4975 explicit make_elim);
  4976 
  4977 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4978   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4979 use instead the strong form,
  4980   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4981 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4982 from destruct-rules;
  4983 
  4984 * Provers: Simplifier.easy_setup provides a fast path to basic
  4985 Simplifier setup for new object-logics;
  4986 
  4987 * Pure: AST translation rules no longer require constant head on LHS;
  4988 
  4989 * Pure: improved name spaces: ambiguous output is qualified; support
  4990 for hiding of names;
  4991 
  4992 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4993 XSYMBOL_HOME; no longer need to do manual configuration in most
  4994 situations;
  4995 
  4996 * system: compression of ML heaps images may now be controlled via -c
  4997 option of isabelle and isatool usedir (currently only observed by
  4998 Poly/ML);
  4999 
  5000 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5001 useful for remote X11);
  5002 
  5003 * system: provide TAGS file for Isabelle sources;
  5004 
  5005 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5006 order;
  5007 
  5008 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5009 timing flag supersedes proof_timing and Toplevel.trace;
  5010 
  5011 * ML: new combinators |>> and |>>> for incremental transformations
  5012 with secondary results (e.g. certain theory extensions):
  5013 
  5014 * ML: PureThy.add_defs gets additional argument to indicate potential
  5015 overloading (usually false);
  5016 
  5017 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5018 results;
  5019 
  5020 
  5021 
  5022 New in Isabelle99 (October 1999)
  5023 --------------------------------
  5024 
  5025 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5026 
  5027 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5028 are no longer simplified.  (This allows the simplifier to unfold recursive
  5029 functional programs.)  To restore the old behaviour, declare
  5030 
  5031     Delcongs [if_weak_cong];
  5032 
  5033 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5034 complement;
  5035 
  5036 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5037 
  5038 * HOL/datatype: mutual_induct_tac no longer exists --
  5039   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5040 
  5041 * HOL/typedef: fixed type inference for representing set; type
  5042 arguments now have to occur explicitly on the rhs as type constraints;
  5043 
  5044 * ZF: The con_defs part of an inductive definition may no longer refer
  5045 to constants declared in the same theory;
  5046 
  5047 * HOL, ZF: the function mk_cases, generated by the inductive
  5048 definition package, has lost an argument.  To simplify its result, it
  5049 uses the default simpset instead of a supplied list of theorems.
  5050 
  5051 * HOL/List: the constructors of type list are now Nil and Cons;
  5052 
  5053 * Simplifier: the type of the infix ML functions
  5054         setSSolver addSSolver setSolver addSolver
  5055 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5056 for packaging solvers. A solver is created via
  5057         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5058 where the string argument is only a comment.
  5059 
  5060 
  5061 *** Proof tools ***
  5062 
  5063 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5064 decision procedure for linear arithmetic. Currently it is used for
  5065 types `nat', `int', and `real' in HOL (see below); it can, should and
  5066 will be instantiated for other types and logics as well.
  5067 
  5068 * The simplifier now accepts rewrite rules with flexible heads, eg
  5069      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5070   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5071   matching.
  5072 
  5073 
  5074 *** General ***
  5075 
  5076 * New Isabelle/Isar subsystem provides an alternative to traditional
  5077 tactical theorem proving; together with the ProofGeneral/isar user
  5078 interface it offers an interactive environment for developing human
  5079 readable proof documents (Isar == Intelligible semi-automated
  5080 reasoning); for further information see isatool doc isar-ref,
  5081 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5082 
  5083 * improved and simplified presentation of theories: better HTML markup
  5084 (including colors), graph views in several sizes; isatool usedir now
  5085 provides a proper interface for user theories (via -P option); actual
  5086 document preparation based on (PDF)LaTeX is available as well (for
  5087 new-style theories only); see isatool doc system for more information;
  5088 
  5089 * native support for Proof General, both for classic Isabelle and
  5090 Isabelle/Isar;
  5091 
  5092 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5093 using the graph browser tool;
  5094 
  5095 * Isabelle manuals now also available as PDF;
  5096 
  5097 * theory loader rewritten from scratch (may not be fully
  5098 bug-compatible); old loadpath variable has been replaced by show_path,
  5099 add_path, del_path, reset_path functions; new operations such as
  5100 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5101 isatool doc ref);
  5102 
  5103 * improved isatool install: option -k creates KDE application icon,
  5104 option -p DIR installs standalone binaries;
  5105 
  5106 * added ML_PLATFORM setting (useful for cross-platform installations);
  5107 more robust handling of platform specific ML images for SML/NJ;
  5108 
  5109 * the settings environment is now statically scoped, i.e. it is never
  5110 created again in sub-processes invoked from isabelle, isatool, or
  5111 Isabelle;
  5112 
  5113 * path element specification '~~' refers to '$ISABELLE_HOME';
  5114 
  5115 * in locales, the "assumes" and "defines" parts may be omitted if
  5116 empty;
  5117 
  5118 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5119 long arrows);
  5120 
  5121 * new print_mode "HTML";
  5122 
  5123 * new flag show_tags controls display of tags of theorems (which are
  5124 basically just comments that may be attached by some tools);
  5125 
  5126 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5127 mode and goal output format:
  5128 
  5129 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5130 244c244
  5131 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5132 ---
  5133 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5134 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5135 181c181
  5136 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5137 ---
  5138 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5139 
  5140 * function bind_thms stores lists of theorems (cf. bind_thm);
  5141 
  5142 * new shorthand tactics ftac, eatac, datac, fatac;
  5143 
  5144 * qed (and friends) now accept "" as result name; in that case the
  5145 theorem is not stored, but proper checks and presentation of the
  5146 result still apply;
  5147 
  5148 * theorem database now also indexes constants "Trueprop", "all",
  5149 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5150 
  5151 
  5152 *** HOL ***
  5153 
  5154 ** HOL arithmetic **
  5155 
  5156 * There are now decision procedures for linear arithmetic over nat and
  5157 int:
  5158 
  5159 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5160 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5161 are treated as atomic; subformulae not involving type `nat' or `int'
  5162 are ignored; quantified subformulae are ignored unless they are
  5163 positive universal or negative existential. The tactic has to be
  5164 invoked by hand and can be a little bit slow. In particular, the
  5165 running time is exponential in the number of occurrences of `min' and
  5166 `max', and `-' on `nat'.
  5167 
  5168 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5169 (negated) (in)equalities among the premises and the conclusion into
  5170 account (i.e. no compound formulae) and does not know about `min' and
  5171 `max', and `-' on `nat'. It is fast and is used automatically by the
  5172 simplifier.
  5173 
  5174 NB: At the moment, these decision procedures do not cope with mixed
  5175 nat/int formulae where the two parts interact, such as `m < n ==>
  5176 int(m) < int(n)'.
  5177 
  5178 * HOL/Numeral provides a generic theory of numerals (encoded
  5179 efficiently as bit strings); setup for types nat/int/real is in place;
  5180 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5181 int, existing theories and proof scripts may require a few additional
  5182 type constraints;
  5183 
  5184 * integer division and remainder can now be performed on constant
  5185 arguments;
  5186 
  5187 * many properties of integer multiplication, division and remainder
  5188 are now available;
  5189 
  5190 * An interface to the Stanford Validity Checker (SVC) is available through the
  5191 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5192 are proved automatically.  SVC must be installed separately, and its results
  5193 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5194 invocation of the underlying oracle).  For SVC see
  5195   http://verify.stanford.edu/SVC
  5196 
  5197 * IsaMakefile: the HOL-Real target now builds an actual image;
  5198 
  5199 
  5200 ** HOL misc **
  5201 
  5202 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5203 (in Isabelle/Isar) -- by Gertrud Bauer;
  5204 
  5205 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5206 analysis for assembly languages with subtypes;
  5207 
  5208 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5209 -- avoids syntactic ambiguities and treats state, transition, and
  5210 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5211 changed syntax and (many) tactics;
  5212 
  5213 * HOL/inductive: Now also handles more general introduction rules such
  5214   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5215   theorems are now maintained within the theory (maintained via the
  5216   "mono" attribute);
  5217 
  5218 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5219   (using function types) such as
  5220 
  5221   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5222 
  5223 * HOL/record: record_simproc (part of the default simpset) takes care
  5224 of selectors applied to updated records; record_split_tac is no longer
  5225 part of the default claset; update_defs may now be removed from the
  5226 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5227 
  5228   claset_ref () := claset() addSWrapper record_split_wrapper;
  5229   Delsimprocs [record_simproc]
  5230 
  5231 * HOL/typedef: fixed type inference for representing set; type
  5232 arguments now have to occur explicitly on the rhs as type constraints;
  5233 
  5234 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5235 names rather than an ML expression;
  5236 
  5237 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5238 supplied later.  Program schemes can be defined, such as
  5239     "While B C s = (if B s then While B C (C s) else s)"
  5240 where the well-founded relation can be chosen after B and C have been given.
  5241 
  5242 * HOL/List: the constructors of type list are now Nil and Cons;
  5243 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5244 course, ML tools referring to List.list.op # etc. have to be adapted;
  5245 
  5246 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5247 disabled by default; run isabelle with option -m HOL to get back to
  5248 the original Gordon/HOL-style output;
  5249 
  5250 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5251 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5252 
  5253 * HOL basic syntax simplified (more orthogonal): all variants of
  5254 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5255 Eps operator is provided as well: "SOME x. P[x]";
  5256 
  5257 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5258 
  5259 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5260 thus available for user theories;
  5261 
  5262 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5263 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5264 time;
  5265 
  5266 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5267 several times and then mp;
  5268 
  5269 
  5270 *** LK ***
  5271 
  5272 * the notation <<...>> is now available as a notation for sequences of
  5273 formulas;
  5274 
  5275 * the simplifier is now installed
  5276 
  5277 * the axiom system has been generalized (thanks to Soren Heilmann)
  5278 
  5279 * the classical reasoner now has a default rule database
  5280 
  5281 
  5282 *** ZF ***
  5283 
  5284 * new primrec section allows primitive recursive functions to be given
  5285 directly (as in HOL) over datatypes and the natural numbers;
  5286 
  5287 * new tactics induct_tac and exhaust_tac for induction (or case
  5288 analysis) over datatypes and the natural numbers;
  5289 
  5290 * the datatype declaration of type T now defines the recursor T_rec;
  5291 
  5292 * simplification automatically does freeness reasoning for datatype
  5293 constructors;
  5294 
  5295 * automatic type-inference, with AddTCs command to insert new
  5296 type-checking rules;
  5297 
  5298 * datatype introduction rules are now added as Safe Introduction rules
  5299 to the claset;
  5300 
  5301 * the syntax "if P then x else y" is now available in addition to
  5302 if(P,x,y);
  5303 
  5304 
  5305 *** Internal programming interfaces ***
  5306 
  5307 * tuned simplifier trace output; new flag debug_simp;
  5308 
  5309 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5310 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5311 
  5312 * AxClass.axclass_tac lost the theory argument;
  5313 
  5314 * tuned current_goals_markers semantics: begin / end goal avoids
  5315 printing empty lines;
  5316 
  5317 * removed prs and prs_fn hook, which was broken because it did not
  5318 include \n in its semantics, forcing writeln to add one
  5319 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5320 string -> unit if you really want to output text without newline;
  5321 
  5322 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5323 plain output, interface builders may have to enable 'isabelle_font'
  5324 mode to get Isabelle font glyphs as before;
  5325 
  5326 * refined token_translation interface; INCOMPATIBILITY: output length
  5327 now of type real instead of int;
  5328 
  5329 * theory loader actions may be traced via new ThyInfo.add_hook
  5330 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5331 your own database of information attached to *whole* theories -- as
  5332 opposed to intra-theory data slots offered via TheoryDataFun;
  5333 
  5334 * proper handling of dangling sort hypotheses (at last!);
  5335 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5336 extra sort hypotheses that can be witnessed from the type signature;
  5337 the force_strip_shyps flag is gone, any remaining shyps are simply
  5338 left in the theorem (with a warning issued by strip_shyps_warning);
  5339 
  5340 
  5341 
  5342 New in Isabelle98-1 (October 1998)
  5343 ----------------------------------
  5344 
  5345 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5346 
  5347 * several changes of automated proof tools;
  5348 
  5349 * HOL: major changes to the inductive and datatype packages, including
  5350 some minor incompatibilities of theory syntax;
  5351 
  5352 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5353 called `inj_on';
  5354 
  5355 * HOL: removed duplicate thms in Arith:
  5356   less_imp_add_less  should be replaced by  trans_less_add1
  5357   le_imp_add_le      should be replaced by  trans_le_add1
  5358 
  5359 * HOL: unary minus is now overloaded (new type constraints may be
  5360 required);
  5361 
  5362 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5363 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5364 now taken as an integer constant.
  5365 
  5366 * Pure: ML function 'theory_of' renamed to 'theory';
  5367 
  5368 
  5369 *** Proof tools ***
  5370 
  5371 * Simplifier:
  5372   1. Asm_full_simp_tac is now more aggressive.
  5373      1. It will sometimes reorient premises if that increases their power to
  5374         simplify.
  5375      2. It does no longer proceed strictly from left to right but may also
  5376         rotate premises to achieve further simplification.
  5377      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5378      old Asm_full_simp_tac in that it does not rotate premises.
  5379   2. The simplifier now knows a little bit about nat-arithmetic.
  5380 
  5381 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5382 allows for selected deletion of wrappers, by introduction of names for
  5383 wrapper functionals.  This implies that addbefore, addSbefore,
  5384 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5385 and that adding two tactics with the same name overwrites the first
  5386 one (emitting a warning).
  5387   type wrapper = (int -> tactic) -> (int -> tactic)
  5388   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5389   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5390   delWrapper, delSWrapper: claset *  string            -> claset
  5391   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5392 
  5393 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5394 semantics; addbefore now affects only the unsafe part of step_tac
  5395 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5396 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5397 by Force_tac;
  5398 
  5399 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5400 compWrapper; added safe wrapper (and access functions for it);
  5401 
  5402 * HOL/split_all_tac is now much faster and fails if there is nothing
  5403 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5404 and the names of the automatically generated variables have changed.
  5405 split_all_tac has moved within claset() from unsafe wrappers to safe
  5406 wrappers, which means that !!-bound variables are split much more
  5407 aggressively, and safe_tac and clarify_tac now split such variables.
  5408 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5409 Note: the same holds for record_split_tac, which does the job of
  5410 split_all_tac for record fields.
  5411 
  5412 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5413 permanently to the default simpset using Addsplits just like
  5414 Addsimps. They can be removed via Delsplits just like
  5415 Delsimps. Lower-case versions are also available.
  5416 
  5417 * HOL/Simplifier: The rule split_if is now part of the default
  5418 simpset. This means that the simplifier will eliminate all occurrences
  5419 of if-then-else in the conclusion of a goal. To prevent this, you can
  5420 either remove split_if completely from the default simpset by
  5421 `Delsplits [split_if]' or remove it in a specific call of the
  5422 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5423 other case splitting rules to/from the default simpset: every datatype
  5424 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5425 t is the name of the datatype).
  5426 
  5427 * Classical reasoner / Simplifier combination: new force_tac (and
  5428 derivatives Force_tac, force) combines rewriting and classical
  5429 reasoning (and whatever other tools) similarly to auto_tac, but is
  5430 aimed to solve the given subgoal completely.
  5431 
  5432 
  5433 *** General ***
  5434 
  5435 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5436 and `goalw': the theory is no longer needed as an explicit argument -
  5437 the current theory context is used; assumptions are no longer returned
  5438 at the ML-level unless one of them starts with ==> or !!; it is
  5439 recommended to convert to these new commands using isatool fixgoal
  5440 (backup your sources first!);
  5441 
  5442 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5443 the current theory context, and 'theory' to lookup stored theories;
  5444 
  5445 * new theory section 'locale' for declaring constants, assumptions and
  5446 definitions that have local scope;
  5447 
  5448 * new theory section 'nonterminals' for purely syntactic types;
  5449 
  5450 * new theory section 'setup' for generic ML setup functions
  5451 (e.g. package initialization);
  5452 
  5453 * the distribution now includes Isabelle icons: see
  5454 lib/logo/isabelle-{small,tiny}.xpm;
  5455 
  5456 * isatool install - install binaries with absolute references to
  5457 ISABELLE_HOME/bin;
  5458 
  5459 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5460 
  5461 * print mode 'emacs' reserved for Isamode;
  5462 
  5463 * support multiple print (ast) translations per constant name;
  5464 
  5465 * theorems involving oracles are now printed with a suffixed [!];
  5466 
  5467 
  5468 *** HOL ***
  5469 
  5470 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5471 
  5472 * HOL/inductive package reorganized and improved: now supports mutual
  5473 definitions such as
  5474 
  5475   inductive EVEN ODD
  5476     intrs
  5477       null "0 : EVEN"
  5478       oddI "n : EVEN ==> Suc n : ODD"
  5479       evenI "n : ODD ==> Suc n : EVEN"
  5480 
  5481 new theorem list "elims" contains an elimination rule for each of the
  5482 recursive sets; inductive definitions now handle disjunctive premises
  5483 correctly (also ZF);
  5484 
  5485 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5486 "mutual_induct" no longer exists - the induction rule is always
  5487 contained in "induct";
  5488 
  5489 
  5490 * HOL/datatype package re-implemented and greatly improved: now
  5491 supports mutually recursive datatypes such as
  5492 
  5493   datatype
  5494     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5495             | SUM ('a aexp) ('a aexp)
  5496             | DIFF ('a aexp) ('a aexp)
  5497             | NUM 'a
  5498   and
  5499     'a bexp = LESS ('a aexp) ('a aexp)
  5500             | AND ('a bexp) ('a bexp)
  5501             | OR ('a bexp) ('a bexp)
  5502 
  5503 as well as indirectly recursive datatypes such as
  5504 
  5505   datatype
  5506     ('a, 'b) term = Var 'a
  5507                   | App 'b ((('a, 'b) term) list)
  5508 
  5509 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5510 induction on mutually / indirectly recursive datatypes.
  5511 
  5512 Primrec equations are now stored in theory and can be accessed via
  5513 <function_name>.simps.
  5514 
  5515 INCOMPATIBILITIES:
  5516 
  5517   - Theories using datatypes must now have theory Datatype as an
  5518     ancestor.
  5519   - The specific <typename>.induct_tac no longer exists - use the
  5520     generic induct_tac instead.
  5521   - natE has been renamed to nat.exhaust - use exhaust_tac
  5522     instead of res_inst_tac ... natE. Note that the variable
  5523     names in nat.exhaust differ from the names in natE, this
  5524     may cause some "fragile" proofs to fail.
  5525   - The theorems split_<typename>_case and split_<typename>_case_asm
  5526     have been renamed to <typename>.split and <typename>.split_asm.
  5527   - Since default sorts of type variables are now handled correctly,
  5528     some datatype definitions may have to be annotated with explicit
  5529     sort constraints.
  5530   - Primrec definitions no longer require function name and type
  5531     of recursive argument.
  5532 
  5533 Consider using isatool fixdatatype to adapt your theories and proof
  5534 scripts to the new package (backup your sources first!).
  5535 
  5536 
  5537 * HOL/record package: considerably improved implementation; now
  5538 includes concrete syntax for record types, terms, updates; theorems
  5539 for surjective pairing and splitting !!-bound record variables; proof
  5540 support is as follows:
  5541 
  5542   1) standard conversions (selectors or updates applied to record
  5543 constructor terms) are part of the standard simpset;
  5544 
  5545   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5546 made part of standard simpset and claset via addIffs;
  5547 
  5548   3) a tactic for record field splitting (record_split_tac) is part of
  5549 the standard claset (addSWrapper);
  5550 
  5551 To get a better idea about these rules you may retrieve them via
  5552 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5553 the name of your record type.
  5554 
  5555 The split tactic 3) conceptually simplifies by the following rule:
  5556 
  5557   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5558 
  5559 Thus any record variable that is bound by meta-all will automatically
  5560 blow up into some record constructor term, consequently the
  5561 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5562 solve record problems automatically.
  5563 
  5564 
  5565 * reorganized the main HOL image: HOL/Integ and String loaded by
  5566 default; theory Main includes everything;
  5567 
  5568 * automatic simplification of integer sums and comparisons, using cancellation;
  5569 
  5570 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5571 
  5572 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5573 
  5574 * many new identities for unions, intersections, set difference, etc.;
  5575 
  5576 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5577 called split_if, split_split, split_sum_case and split_nat_case (to go
  5578 with add/delsplits);
  5579 
  5580 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5581 (?x::unit) = (); this is made part of the default simpset, which COULD
  5582 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5583 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5584 unit_abs_eta_conv is added in order to counter the effect of
  5585 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5586 %u.f();
  5587 
  5588 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5589 makes more sense);
  5590 
  5591 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5592   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5593   disjointness reasoning but breaking a few old proofs.
  5594 
  5595 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5596 to 'converse' from 'inverse' (for compatibility with ZF and some
  5597 literature);
  5598 
  5599 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5600 the well-founded relation;
  5601 
  5602 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5603     Compl A.  The "Compl" syntax remains available as input syntax for this
  5604     release ONLY.
  5605 
  5606 * HOL/Update: new theory of function updates:
  5607     f(a:=b) == %x. if x=a then b else f x
  5608 may also be iterated as in f(a:=b,c:=d,...);
  5609 
  5610 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5611 
  5612 * HOL/List:
  5613   - new function list_update written xs[i:=v] that updates the i-th
  5614     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5615   - new function `upt' written [i..j(] which generates the list
  5616     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5617     bound write [i..j], which is a shorthand for [i..j+1(].
  5618   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5619 
  5620 * HOL/Arith:
  5621   - removed 'pred' (predecessor) function;
  5622   - generalized some theorems about n-1;
  5623   - many new laws about "div" and "mod";
  5624   - new laws about greatest common divisors (see theory ex/Primes);
  5625 
  5626 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5627 instead of "inverse";
  5628 
  5629 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5630   of the multiset ordering;
  5631 
  5632 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5633   (not included by default);
  5634 
  5635 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5636 
  5637 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5638   programs, i.e. different program variables may have different types.
  5639 
  5640 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5641   [previously, this check worked only if the rewrite rule was unconditional]
  5642   Now rew can involve either definitions or equalities (either == or =).
  5643 
  5644 
  5645 *** ZF ***
  5646 
  5647 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5648   only the theorems proved on ZF.ML;
  5649 
  5650 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5651   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5652   disjointness reasoning but breaking a few old proofs.
  5653 
  5654 * ZF/Update: new theory of function updates
  5655     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5656   may also be iterated as in f(a:=b,c:=d,...);
  5657 
  5658 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5659 
  5660 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5661   [previously, this check worked only if the rewrite rule was unconditional]
  5662   Now rew can involve either definitions or equalities (either == or =).
  5663 
  5664 * case_tac provided for compatibility with HOL
  5665     (like the old excluded_middle_tac, but with subgoals swapped)
  5666 
  5667 
  5668 *** Internal programming interfaces ***
  5669 
  5670 * Pure: several new basic modules made available for general use, see
  5671 also src/Pure/README;
  5672 
  5673 * improved the theory data mechanism to support encapsulation (data
  5674 kind name replaced by private Object.kind, acting as authorization
  5675 key); new type-safe user interface via functor TheoryDataFun; generic
  5676 print_data function becomes basically useless;
  5677 
  5678 * removed global_names compatibility flag -- all theory declarations
  5679 are qualified by default;
  5680 
  5681 * module Pure/Syntax now offers quote / antiquote translation
  5682 functions (useful for Hoare logic etc. with implicit dependencies);
  5683 see HOL/ex/Antiquote for an example use;
  5684 
  5685 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5686 cterm -> thm;
  5687 
  5688 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5689 subgoal;
  5690 
  5691 * Display.print_goals function moved to Locale.print_goals;
  5692 
  5693 * standard print function for goals supports current_goals_markers
  5694 variable for marking begin of proof, end of proof, start of goal; the
  5695 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5696 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5697 for example;
  5698 
  5699 
  5700 
  5701 New in Isabelle98 (January 1998)
  5702 --------------------------------
  5703 
  5704 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5705 
  5706 * changed lexical syntax of terms / types: dots made part of long
  5707 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5708 
  5709 * simpset (and claset) reference variable replaced by functions
  5710 simpset / simpset_ref;
  5711 
  5712 * no longer supports theory aliases (via merge) and non-trivial
  5713 implicit merge of thms' signatures;
  5714 
  5715 * most internal names of constants changed due to qualified names;
  5716 
  5717 * changed Pure/Sequence interface (see Pure/seq.ML);
  5718 
  5719 
  5720 *** General Changes ***
  5721 
  5722 * hierachically structured name spaces (for consts, types, axms, thms
  5723 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5724 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5725 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5726 long_names for fully qualified output names; NOTE: ML programs
  5727 (special tactics, packages etc.) referring to internal names may have
  5728 to be adapted to cope with fully qualified names; in case of severe
  5729 backward campatibility problems try setting 'global_names' at compile
  5730 time to have enrything declared within a flat name space; one may also
  5731 fine tune name declarations in theories via the 'global' and 'local'
  5732 section;
  5733 
  5734 * reimplemented the implicit simpset and claset using the new anytype
  5735 data filed in signatures; references simpset:simpset ref etc. are
  5736 replaced by functions simpset:unit->simpset and
  5737 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5738 to patch your ML files accordingly;
  5739 
  5740 * HTML output now includes theory graph data for display with Java
  5741 applet or isatool browser; data generated automatically via isatool
  5742 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5743 
  5744 * defs may now be conditional; improved rewrite_goals_tac to handle
  5745 conditional equations;
  5746 
  5747 * defs now admits additional type arguments, using TYPE('a) syntax;
  5748 
  5749 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5750 creates a new theory node; implicit merge of thms' signatures is
  5751 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5752 transfer:theory->thm->thm in (rare) cases;
  5753 
  5754 * improved handling of draft signatures / theories; draft thms (and
  5755 ctyps, cterms) are automatically promoted to real ones;
  5756 
  5757 * slightly changed interfaces for oracles: admit many per theory, named
  5758 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5759 
  5760 * print_goals: optional output of const types (set show_consts and
  5761 show_types);
  5762 
  5763 * improved output of warnings (###) and errors (***);
  5764 
  5765 * subgoal_tac displays a warning if the new subgoal has type variables;
  5766 
  5767 * removed old README and Makefiles;
  5768 
  5769 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5770 
  5771 * removed obsolete init_pps and init_database;
  5772 
  5773 * deleted the obsolete tactical STATE, which was declared by
  5774     fun STATE tacfun st = tacfun st st;
  5775 
  5776 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5777 (which abbreviates $HOME);
  5778 
  5779 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5780 use isatool fixseq to adapt your ML programs (this works for fully
  5781 qualified references to the Sequence structure only!);
  5782 
  5783 * use_thy no longer requires writable current directory; it always
  5784 reloads .ML *and* .thy file, if either one is out of date;
  5785 
  5786 
  5787 *** Classical Reasoner ***
  5788 
  5789 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5790 tactics that use classical reasoning to simplify a subgoal without
  5791 splitting it into several subgoals;
  5792 
  5793 * Safe_tac: like safe_tac but uses the default claset;
  5794 
  5795 
  5796 *** Simplifier ***
  5797 
  5798 * added simplification meta rules:
  5799     (asm_)(full_)simplify: simpset -> thm -> thm;
  5800 
  5801 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5802 logics (again);
  5803 
  5804 * added prems argument to simplification procedures;
  5805 
  5806 * HOL, FOL, ZF: added infix function `addsplits':
  5807   instead of `<simpset> setloop (split_tac <thms>)'
  5808   you can simply write `<simpset> addsplits <thms>'
  5809 
  5810 
  5811 *** Syntax ***
  5812 
  5813 * TYPE('a) syntax for type reflection terms;
  5814 
  5815 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5816 
  5817 * pretty printer: changed order of mixfix annotation preference (again!);
  5818 
  5819 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5820 
  5821 
  5822 *** HOL ***
  5823 
  5824 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5825   with `addloop' of the simplifier to faciliate case splitting in premises.
  5826 
  5827 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5828 
  5829 * HOL/Auth: new protocol proofs including some for the Internet
  5830   protocol TLS;
  5831 
  5832 * HOL/Map: new theory of `maps' a la VDM;
  5833 
  5834 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5835 cancelling out common nat summands from =, <, <= (in)equalities, or
  5836 differences; simplification procedures nat_cancel_factor for
  5837 cancelling common factor from =, <, <= (in)equalities over natural
  5838 sums; nat_cancel contains both kinds of procedures, it is installed by
  5839 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5840 
  5841 * HOL/simplifier: terms of the form
  5842   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5843   are rewritten to
  5844   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5845   and those of the form
  5846   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5847   are rewritten to
  5848   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5849 
  5850 * HOL/datatype
  5851   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5852 
  5853   P(t_case f1 ... fn x) =
  5854      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5855         ...
  5856        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5857      )
  5858 
  5859   and a theorem `split_t_case_asm' of the form
  5860 
  5861   P(t_case f1 ... fn x) =
  5862     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5863         ...
  5864        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5865      )
  5866   which can be added to a simpset via `addsplits'. The existing theorems
  5867   expand_list_case and expand_option_case have been renamed to
  5868   split_list_case and split_option_case.
  5869 
  5870 * HOL/Arithmetic:
  5871   - `pred n' is automatically converted to `n-1'.
  5872     Users are strongly encouraged not to use `pred' any longer,
  5873     because it will disappear altogether at some point.
  5874   - Users are strongly encouraged to write "0 < n" rather than
  5875     "n ~= 0". Theorems and proof tools have been modified towards this
  5876     `standard'.
  5877 
  5878 * HOL/Lists:
  5879   the function "set_of_list" has been renamed "set" (and its theorems too);
  5880   the function "nth" now takes its arguments in the reverse order and
  5881   has acquired the infix notation "!" as in "xs!n".
  5882 
  5883 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5884 
  5885 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5886   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5887 
  5888 * HOL/record: extensible records with schematic structural subtyping
  5889 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5890 still lacks various theorems and concrete record syntax;
  5891 
  5892 
  5893 *** HOLCF ***
  5894 
  5895 * removed "axioms" and "generated by" sections;
  5896 
  5897 * replaced "ops" section by extended "consts" section, which is capable of
  5898   handling the continuous function space "->" directly;
  5899 
  5900 * domain package:
  5901   . proves theorems immediately and stores them in the theory,
  5902   . creates hierachical name space,
  5903   . now uses normal mixfix annotations (instead of cinfix...),
  5904   . minor changes to some names and values (for consistency),
  5905   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5906   . separator between mutual domain defs: changed "," to "and",
  5907   . improved handling of sort constraints;  now they have to
  5908     appear on the left-hand side of the equations only;
  5909 
  5910 * fixed LAM <x,y,zs>.b syntax;
  5911 
  5912 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5913 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5914 
  5915 
  5916 *** FOL and ZF ***
  5917 
  5918 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5919   with `addloop' of the simplifier to faciliate case splitting in premises.
  5920 
  5921 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5922 in HOL, they strip ALL and --> from proved theorems;
  5923 
  5924 
  5925 
  5926 New in Isabelle94-8 (May 1997)
  5927 ------------------------------
  5928 
  5929 *** General Changes ***
  5930 
  5931 * new utilities to build / run / maintain Isabelle etc. (in parts
  5932 still somewhat experimental); old Makefiles etc. still functional;
  5933 
  5934 * new 'Isabelle System Manual';
  5935 
  5936 * INSTALL text, together with ./configure and ./build scripts;
  5937 
  5938 * reimplemented type inference for greater efficiency, better error
  5939 messages and clean internal interface;
  5940 
  5941 * prlim command for dealing with lots of subgoals (an easier way of
  5942 setting goals_limit);
  5943 
  5944 
  5945 *** Syntax ***
  5946 
  5947 * supports alternative (named) syntax tables (parser and pretty
  5948 printer); internal interface is provided by add_modesyntax(_i);
  5949 
  5950 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5951 be used in conjunction with the Isabelle symbol font; uses the
  5952 "symbols" syntax table;
  5953 
  5954 * added token_translation interface (may translate name tokens in
  5955 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5956 the current print_mode); IMPORTANT: user print translation functions
  5957 are responsible for marking newly introduced bounds
  5958 (Syntax.mark_boundT);
  5959 
  5960 * token translations for modes "xterm" and "xterm_color" that display
  5961 names in bold, underline etc. or colors (which requires a color
  5962 version of xterm);
  5963 
  5964 * infixes may now be declared with names independent of their syntax;
  5965 
  5966 * added typed_print_translation (like print_translation, but may
  5967 access type of constant);
  5968 
  5969 
  5970 *** Classical Reasoner ***
  5971 
  5972 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5973 some limitations.  Blast_tac...
  5974   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5975   + ignores elimination rules that don't have the correct format
  5976         (the conclusion MUST be a formula variable)
  5977   + ignores types, which can make HOL proofs fail
  5978   + rules must not require higher-order unification, e.g. apply_type in ZF
  5979     [message "Function Var's argument not a bound variable" relates to this]
  5980   + its proof strategy is more general but can actually be slower
  5981 
  5982 * substitution with equality assumptions no longer permutes other
  5983 assumptions;
  5984 
  5985 * minor changes in semantics of addafter (now called addaltern); renamed
  5986 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5987 (and access functions for it);
  5988 
  5989 * improved combination of classical reasoner and simplifier:
  5990   + functions for handling clasimpsets
  5991   + improvement of addss: now the simplifier is called _after_ the
  5992     safe steps.
  5993   + safe variant of addss called addSss: uses safe simplifications
  5994     _during_ the safe steps. It is more complete as it allows multiple
  5995     instantiations of unknowns (e.g. with slow_tac).
  5996 
  5997 *** Simplifier ***
  5998 
  5999 * added interface for simplification procedures (functions that
  6000 produce *proven* rewrite rules on the fly, depending on current
  6001 redex);
  6002 
  6003 * ordering on terms as parameter (used for ordered rewriting);
  6004 
  6005 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6006 
  6007 * the solver is now split into a safe and an unsafe part.
  6008 This should be invisible for the normal user, except that the
  6009 functions setsolver and addsolver have been renamed to setSolver and
  6010 addSolver; added safe_asm_full_simp_tac;
  6011 
  6012 
  6013 *** HOL ***
  6014 
  6015 * a generic induction tactic `induct_tac' which works for all datatypes and
  6016 also for type `nat';
  6017 
  6018 * a generic case distinction tactic `exhaust_tac' which works for all
  6019 datatypes and also for type `nat';
  6020 
  6021 * each datatype comes with a function `size';
  6022 
  6023 * patterns in case expressions allow tuple patterns as arguments to
  6024 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6025 
  6026 * primrec now also works with type nat;
  6027 
  6028 * recdef: a new declaration form, allows general recursive functions to be
  6029 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6030 
  6031 * the constant for negation has been renamed from "not" to "Not" to
  6032 harmonize with FOL, ZF, LK, etc.;
  6033 
  6034 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6035 infinite lists;
  6036 
  6037 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6038 
  6039 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6040 problems in commutative rings, using axiomatic type classes for + and *;
  6041 
  6042 * more examples in HOL/MiniML and HOL/Auth;
  6043 
  6044 * more default rewrite rules for quantifiers, union/intersection;
  6045 
  6046 * a new constant `arbitrary == @x.False';
  6047 
  6048 * HOLCF/IOA replaces old HOL/IOA;
  6049 
  6050 * HOLCF changes: derived all rules and arities
  6051   + axiomatic type classes instead of classes
  6052   + typedef instead of faking type definitions
  6053   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6054   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6055   + eliminated the types void, one, tr
  6056   + use unit lift and bool lift (with translations) instead of one and tr
  6057   + eliminated blift from Lift3.thy (use Def instead of blift)
  6058   all eliminated rules are derived as theorems --> no visible changes ;
  6059 
  6060 
  6061 *** ZF ***
  6062 
  6063 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6064 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6065 as ZF_cs addSIs [equalityI];
  6066 
  6067 
  6068 
  6069 New in Isabelle94-7 (November 96)
  6070 ---------------------------------
  6071 
  6072 * allowing negative levels (as offsets) in prlev and choplev;
  6073 
  6074 * super-linear speedup for large simplifications;
  6075 
  6076 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6077 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6078 FAIL); can suppress it using the command Delsimps (ex_simps @
  6079 all_simps); De Morgan laws are also now included, by default;
  6080 
  6081 * improved printing of ==>  :  ~:
  6082 
  6083 * new object-logic "Sequents" adds linear logic, while replacing LK
  6084 and Modal (thanks to Sara Kalvala);
  6085 
  6086 * HOL/Auth: correctness proofs for authentication protocols;
  6087 
  6088 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6089 examples on HOL/Auth);
  6090 
  6091 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6092 the rewriter and classical reasoner simultaneously;
  6093 
  6094 * function uresult no longer returns theorems in "standard" format;
  6095 regain previous version by: val uresult = standard o uresult;
  6096 
  6097 
  6098 
  6099 New in Isabelle94-6
  6100 -------------------
  6101 
  6102 * oracles -- these establish an interface between Isabelle and trusted
  6103 external reasoners, which may deliver results as theorems;
  6104 
  6105 * proof objects (in particular record all uses of oracles);
  6106 
  6107 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6108 
  6109 * "constdefs" section in theory files;
  6110 
  6111 * "primrec" section (HOL) no longer requires names;
  6112 
  6113 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6114 
  6115 
  6116 
  6117 New in Isabelle94-5
  6118 -------------------
  6119 
  6120 * reduced space requirements;
  6121 
  6122 * automatic HTML generation from theories;
  6123 
  6124 * theory files no longer require "..." (quotes) around most types;
  6125 
  6126 * new examples, including two proofs of the Church-Rosser theorem;
  6127 
  6128 * non-curried (1994) version of HOL is no longer distributed;
  6129 
  6130 
  6131 
  6132 New in Isabelle94-4
  6133 -------------------
  6134 
  6135 * greatly reduced space requirements;
  6136 
  6137 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6138 
  6139 * searchable theorem database (see the section "Retrieving theorems" on
  6140 page 8 of the Reference Manual);
  6141 
  6142 * new examples, including Grabczewski's monumental case study of the
  6143 Axiom of Choice;
  6144 
  6145 * The previous version of HOL renamed to Old_HOL;
  6146 
  6147 * The new version of HOL (previously called CHOL) uses a curried syntax
  6148 for functions.  Application looks like f a b instead of f(a,b);
  6149 
  6150 * Mutually recursive inductive definitions finally work in HOL;
  6151 
  6152 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6153 translates to the operator "split";
  6154 
  6155 
  6156 
  6157 New in Isabelle94-3
  6158 -------------------
  6159 
  6160 * new infix operator, addss, allowing the classical reasoner to
  6161 perform simplification at each step of its search.  Example:
  6162         fast_tac (cs addss ss)
  6163 
  6164 * a new logic, CHOL, the same as HOL, but with a curried syntax
  6165 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  6166 look like (a,b) instead of <a,b>;
  6167 
  6168 * PLEASE NOTE: CHOL will eventually replace HOL!
  6169 
  6170 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  6171 It translates to the operator "split".  A new theory of integers is available;
  6172 
  6173 * In ZF, integer numerals now denote two's-complement binary integers.
  6174 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  6175 
  6176 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  6177 of the Axiom of Choice;
  6178 
  6179 
  6180 
  6181 New in Isabelle94-2
  6182 -------------------
  6183 
  6184 * Significantly faster resolution;
  6185 
  6186 * the different sections in a .thy file can now be mixed and repeated
  6187 freely;
  6188 
  6189 * Database of theorems for FOL, HOL and ZF.  New
  6190 commands including qed, qed_goal and bind_thm store theorems in the database.
  6191 
  6192 * Simple database queries: return a named theorem (get_thm) or all theorems of
  6193 a given theory (thms_of), or find out what theory a theorem was proved in
  6194 (theory_of_thm);
  6195 
  6196 * Bugs fixed in the inductive definition and datatype packages;
  6197 
  6198 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  6199 and HOL_dup_cs obsolete;
  6200 
  6201 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  6202 have been removed;
  6203 
  6204 * Simpler definition of function space in ZF;
  6205 
  6206 * new results about cardinal and ordinal arithmetic in ZF;
  6207 
  6208 * 'subtype' facility in HOL for introducing new types as subsets of existing
  6209 types;
  6210 
  6211 :mode=text:wrap=hard:maxLineLen=72: