NEWS
author nipkow
Tue Mar 24 14:08:13 2009 +0100 (2009-03-24)
changeset 30706 e20227b5e6a3
parent 30609 983e8b6e4e69
child 30728 f0aeca99b5d9
child 30740 2d3ae5a7edb2
permissions -rw-r--r--
NEWS: [arith]
     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/ex/Code_Antiq for a toy
   502 example, or HOL/Complex/ex/ReflectedFerrack for a more ambitious
   503 application.  In future you ought refrain from ad-hoc compiling
   504 generated SML code on the ML toplevel.  Note that (for technical
   505 reasons) @{code} cannot refer to constants for which user-defined
   506 serializations are set.  Refer to the corresponding ML counterpart
   507 directly in that cases.
   508 
   509 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   510 Complex_Main.thy remain as they are.
   511 
   512 * New image HOL-Plain provides a minimal HOL with the most important
   513 tools available (inductive, datatype, primrec, ...).  By convention
   514 the corresponding theory Plain should be ancestor of every further
   515 (library) theory.  Some library theories now have ancestor Plain
   516 (instead of Main), thus theory Main occasionally has to be imported
   517 explicitly.
   518 
   519 * The metis method now fails in the usual manner, rather than raising
   520 an exception, if it determines that it cannot prove the theorem.
   521 
   522 * The metis method no longer fails because the theorem is too trivial
   523 (contains the empty clause).
   524 
   525 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   526 as the structured Isar versions "cases" and "induct", cf. the
   527 corresponding "cases" and "induct" attributes.  Mutual induction rules
   528 are now presented as a list of individual projections
   529 (e.g. foo_bar.inducts for types foo and bar); the old format with
   530 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   531 rare situations a different rule is selected --- notably nested tuple
   532 elimination instead of former prod.exhaust: use explicit (case_tac t
   533 rule: prod.exhaust) here.
   534 
   535 * Attributes "cases", "induct", "coinduct" support "del" option.
   536 
   537 * Removed fact "case_split_thm", which duplicates "case_split".
   538 
   539 * Command 'rep_datatype': instead of theorem names the command now
   540 takes a list of terms denoting the constructors of the type to be
   541 represented as datatype.  The characteristic theorems have to be
   542 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   543 have disappeared in favour of existing ones:
   544 
   545     unit_induct                 ~> unit.induct
   546     prod_induct                 ~> prod.induct
   547     sum_induct                  ~> sum.induct
   548     Suc_Suc_eq                  ~> nat.inject
   549     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   550 
   551 * The option datatype has been moved to a new theory HOL/Option.thy.
   552 Renamed option_map to Option.map, and o2s to Option.set.
   553 
   554 * Library/Nat_Infinity: added addition, numeral syntax and more
   555 instantiations for algebraic structures.  Removed some duplicate
   556 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   557 
   558 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   559 menu.
   560 
   561 * Linear arithmetic now ignores all inequalities when
   562 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   563 
   564 
   565 *** HOL-Algebra ***
   566 
   567 * New locales for orders and lattices where the equivalence relation
   568 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   569 locales use a record structure with field eq for the equivalence.
   570 
   571 * New theory of factorial domains.
   572 
   573 * Units_l_inv and Units_r_inv are now simprules by default.
   574 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   575 and/or r_inv will now also require deletion of these lemmas.
   576 
   577 * Renamed the following theorems.  INCOMPATIBILITY.
   578 UpperD ~> Upper_memD
   579 LowerD ~> Lower_memD
   580 least_carrier ~> least_closed
   581 greatest_carrier ~> greatest_closed
   582 greatest_Lower_above ~> greatest_Lower_below
   583 one_zero ~> carrier_one_zero
   584 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   585 
   586 
   587 *** HOL-NSA ***
   588 
   589 * Created new image HOL-NSA, containing theories of nonstandard
   590 analysis which were previously part of HOL-Complex.  Entry point
   591 Hyperreal.thy remains valid, but theories formerly using
   592 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   593 
   594 
   595 *** ZF ***
   596 
   597 * Proof of Zorn's Lemma for partial orders.
   598 
   599 
   600 *** HOLCF ***
   601 
   602 * Reimplemented the simplification procedure for proving continuity
   603 subgoals.  The new simproc is extensible; users can declare additional
   604 continuity introduction rules with the attribute [cont2cont].
   605 
   606 * The continuity simproc now uses a different introduction rule for
   607 solving continuity subgoals on terms with lambda abstractions.  In
   608 some rare cases the new simproc may fail to solve subgoals that the
   609 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   610 Potential INCOMPATIBILITY.
   611 
   612 * The syntax of the fixrec package has changed.  The specification
   613 syntax now conforms in style to definition, primrec, function, etc.
   614 See HOLCF/ex/Fixrec_ex.thy for examples.  INCOMPATIBILITY.
   615 
   616 
   617 *** ML ***
   618 
   619 * High-level support for concurrent ML programming, see
   620 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   621 particularly convenient to organize independent functional
   622 computations.  The concept of "synchronized variables" provides a
   623 higher-order interface for components with shared state, avoiding the
   624 delicate details of mutexes and condition variables.  [Poly/ML 5.2.1
   625 or later]
   626 
   627 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   628 and Method.setup, as well as commands 'attribute_setup' and
   629 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   630 existing code accordingly, or use plain 'setup' together with old
   631 Method.add_method.
   632 
   633 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   634 to 'a -> thm, while results are always tagged with an authentic oracle
   635 name.  The Isar command 'oracle' is now polymorphic, no argument type
   636 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   637 accordingly.  Note that extra performance may be gained by producing
   638 the cterm carefully, avoiding slow Thm.cterm_of.
   639 
   640 * ML bindings produced via Isar commands are stored within the Isar
   641 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   642 become thread-safe and work with undo as expected (concerning
   643 top-level bindings, not side-effects on global references).
   644 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   645 compiler at runtime; really global bindings need to be given outside a
   646 theory. [Poly/ML 5.2 or later]
   647 
   648 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   649 context. Top-level ML bindings are stored within the proof context in
   650 a purely sequential fashion, disregarding the nested proof structure.
   651 ML bindings introduced by 'ML_prf' are discarded at the end of the
   652 proof.  [Poly/ML 5.2 or later]
   653 
   654 * Generic Toplevel.add_hook interface allows to analyze the result of
   655 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   656 for theorem dependency output of transactions resulting in a new
   657 theory state.
   658 
   659 * More systematic treatment of long names, abstract name bindings, and
   660 name space operations.  Basic operations on qualified names have been
   661 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   662 Long_Name.append.  Old type bstring has been mostly replaced by
   663 abstract type binding (see structure Binding), which supports precise
   664 qualification (by packages and local theory targets), as well as
   665 proper tracking of source positions.  INCOMPATIBILITY, need to wrap
   666 old bstring values into Binding.name, or better pass through abstract
   667 bindings everywhere.  See further src/Pure/General/long_name.ML,
   668 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   669 
   670 * Simplified interface for defining document antiquotations via
   671 ThyOutput.antiquotation, ThyOutput.output, and optionally
   672 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   673 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   674 examples.
   675 
   676 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   677 LocalTheory.note etc.) now refer to the *full* internal name, not the
   678 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   679 
   680 * Rules and tactics that read instantiations (read_instantiate,
   681 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   682 context, which is required for parsing and type-checking.  Moreover,
   683 the variables are specified as plain indexnames, not string encodings
   684 thereof.  INCOMPATIBILITY.
   685 
   686 * Disposed old type and term read functions (Sign.read_def_typ,
   687 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   688 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   689 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   690 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   691 resort for legacy applications.
   692 
   693 * Disposed old declarations, tactics, tactic combinators that refer to
   694 the simpset or claset of an implicit theory (such as Addsimps,
   695 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   696 embedded ML text, or local_simpset_of with a proper context passed as
   697 explicit runtime argument.
   698 
   699 * Antiquotations: block-structured compilation context indicated by
   700 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   701 
   702   @{let ?pat = term}                      - term abbreviation (HO matching)
   703   @{note name = fact}                     - fact abbreviation
   704   @{thm fact}                             - singleton fact (with attributes)
   705   @{thms fact}                            - general fact (with attributes)
   706   @{lemma prop by method}                 - singleton goal
   707   @{lemma prop by meth1 meth2}            - singleton goal
   708   @{lemma prop1 ... propN by method}      - general goal
   709   @{lemma prop1 ... propN by meth1 meth2} - general goal
   710   @{lemma (open) ...}                     - open derivation
   711 
   712 
   713 *** System ***
   714 
   715 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   716 Poly/ML 5.2.1 or later.
   717 
   718 * The Isabelle "emacs" tool provides a specific interface to invoke
   719 Proof General / Emacs, with more explicit failure if that is not
   720 installed (the old isabelle-interface script silently falls back on
   721 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   722 installation location of the Proof General distribution.
   723 
   724 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   725 the Isabelle process into a JVM/Scala application.  See
   726 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   727 process wrapper has been discontinued.)
   728 
   729 * Status messages (with exact source position information) are
   730 emitted, if proper markup print mode is enabled.  This allows
   731 user-interface components to provide detailed feedback on internal
   732 prover operations.
   733 
   734 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   735 
   736 
   737 
   738 New in Isabelle2008 (June 2008)
   739 -------------------------------
   740 
   741 *** General ***
   742 
   743 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   744 and updated, with formally checked references as hyperlinks.
   745 
   746 * Theory loader: use_thy (and similar operations) no longer set the
   747 implicit ML context, which was occasionally hard to predict and in
   748 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   749 provides a proper context already.
   750 
   751 * Theory loader: old-style ML proof scripts being *attached* to a thy
   752 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   753 'use' within a theory file will do the job.
   754 
   755 * Name space merge now observes canonical order, i.e. the second space
   756 is inserted into the first one, while existing entries in the first
   757 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   758 swap theory imports.
   759 
   760 * Syntax: symbol \<chi> is now considered a letter.  Potential
   761 INCOMPATIBILITY in identifier syntax etc.
   762 
   763 * Outer syntax: string tokens no longer admit escaped white space,
   764 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   765 white space without escapes.
   766 
   767 * Outer syntax: string tokens may contain arbitrary character codes
   768 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   769 "foo_bar".
   770 
   771 
   772 *** Pure ***
   773 
   774 * Context-dependent token translations.  Default setup reverts locally
   775 fixed variables, and adds hilite markup for undeclared frees.
   776 
   777 * Unused theorems can be found using the new command 'unused_thms'.
   778 There are three ways of invoking it:
   779 
   780 (1) unused_thms
   781      Only finds unused theorems in the current theory.
   782 
   783 (2) unused_thms thy_1 ... thy_n -
   784      Finds unused theorems in the current theory and all of its ancestors,
   785      excluding the theories thy_1 ... thy_n and all of their ancestors.
   786 
   787 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   788      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   789      their ancestors, excluding the theories thy_1 ... thy_n and all of
   790      their ancestors.
   791 
   792 In order to increase the readability of the list produced by
   793 unused_thms, theorems that have been created by a particular instance
   794 of a theory command such as 'inductive' or 'function' are considered
   795 to belong to the same "group", meaning that if at least one theorem in
   796 this group is used, the other theorems in the same group are no longer
   797 reported as unused.  Moreover, if all theorems in the group are
   798 unused, only one theorem in the group is displayed.
   799 
   800 Note that proof objects have to be switched on in order for
   801 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   802 usually the case when using Proof General with the default settings).
   803 
   804 * Authentic naming of facts disallows ad-hoc overwriting of previous
   805 theorems within the same name space.  INCOMPATIBILITY, need to remove
   806 duplicate fact bindings, or even accidental fact duplications.  Note
   807 that tools may maintain dynamically scoped facts systematically, using
   808 PureThy.add_thms_dynamic.
   809 
   810 * Command 'hide' now allows to hide from "fact" name space as well.
   811 
   812 * Eliminated destructive theorem database, simpset, claset, and
   813 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   814 update of theories within ML code.
   815 
   816 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   817 INCOMPATIBILITY, object-logics depending on former Pure require
   818 additional setup PureThy.old_appl_syntax_setup; object-logics
   819 depending on former CPure need to refer to Pure.
   820 
   821 * Commands 'use' and 'ML' are now purely functional, operating on
   822 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   823 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   824 INCOMPATIBILITY.
   825 
   826 * Command 'setup': discontinued implicit version with ML reference.
   827 
   828 * Instantiation target allows for simultaneous specification of class
   829 instance operations together with an instantiation proof.
   830 Type-checking phase allows to refer to class operations uniformly.
   831 See src/HOL/Complex/Complex.thy for an Isar example and
   832 src/HOL/Library/Eval.thy for an ML example.
   833 
   834 * Indexing of literal facts: be more serious about including only
   835 facts from the visible specification/proof context, but not the
   836 background context (locale etc.).  Affects `prop` notation and method
   837 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   838 situations.
   839 
   840 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   841 "(open)" option, which used to expose internal bound variables to the
   842 proof text.
   843 
   844 * Isar statements: removed obsolete case "rule_context".
   845 INCOMPATIBILITY, better use explicit fixes/assumes.
   846 
   847 * Locale proofs: default proof step now includes 'unfold_locales';
   848 hence 'proof' without argument may be used to unfold locale
   849 predicates.
   850 
   851 
   852 *** Document preparation ***
   853 
   854 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   855 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   856 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   857 spot); renamed link color from "darkblue" to "linkcolor" (default
   858 value unchanged, can be redefined via \definecolor); no longer sets
   859 "a4paper" option (unnecessary or even intrusive).
   860 
   861 * Antiquotation @{lemma A method} proves proposition A by the given
   862 method (either a method name or a method name plus (optional) method
   863 arguments in parentheses) and prints A just like @{prop A}.
   864 
   865 
   866 *** HOL ***
   867 
   868 * New primrec package.  Specification syntax conforms in style to
   869 definition/function/....  No separate induction rule is provided.  The
   870 "primrec" command distinguishes old-style and new-style specifications
   871 by syntax.  The former primrec package is now named OldPrimrecPackage.
   872 When adjusting theories, beware: constants stemming from new-style
   873 primrec specifications have authentic syntax.
   874 
   875 * Metis prover is now an order of magnitude faster, and also works
   876 with multithreading.
   877 
   878 * Metis: the maximum number of clauses that can be produced from a
   879 theorem is now given by the attribute max_clauses.  Theorems that
   880 exceed this number are ignored, with a warning printed.
   881 
   882 * Sledgehammer no longer produces structured proofs by default. To
   883 enable, declare [[sledgehammer_full = true]].  Attributes
   884 reconstruction_modulus, reconstruction_sorts renamed
   885 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   886 
   887 * Method "induct_scheme" derives user-specified induction rules
   888 from well-founded induction and completeness of patterns. This factors
   889 out some operations that are done internally by the function package
   890 and makes them available separately.  See
   891 src/HOL/ex/Induction_Scheme.thy for examples.
   892 
   893 * More flexible generation of measure functions for termination
   894 proofs: Measure functions can be declared by proving a rule of the
   895 form "is_measure f" and giving it the [measure_function] attribute.
   896 The "is_measure" predicate is logically meaningless (always true), and
   897 just guides the heuristic.  To find suitable measure functions, the
   898 termination prover sets up the goal "is_measure ?f" of the appropriate
   899 type and generates all solutions by prolog-style backwards proof using
   900 the declared rules.
   901 
   902 This setup also deals with rules like 
   903 
   904   "is_measure f ==> is_measure (list_size f)"
   905 
   906 which accommodates nested datatypes that recurse through lists.
   907 Similar rules are predeclared for products and option types.
   908 
   909 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   910 
   911   INCOMPATIBILITIES:
   912 
   913   - Definitions of overloaded constants on sets have to be replaced by
   914     definitions on => and bool.
   915 
   916   - Some definitions of overloaded operators on sets can now be proved
   917     using the definitions of the operators on => and bool.  Therefore,
   918     the following theorems have been renamed:
   919 
   920       subset_def   -> subset_eq
   921       psubset_def  -> psubset_eq
   922       set_diff_def -> set_diff_eq
   923       Compl_def    -> Compl_eq
   924       Sup_set_def  -> Sup_set_eq
   925       Inf_set_def  -> Inf_set_eq
   926       sup_set_def  -> sup_set_eq
   927       inf_set_def  -> inf_set_eq
   928 
   929   - Due to the incompleteness of the HO unification algorithm, some
   930     rules such as subst may require manual instantiation, if some of
   931     the unknowns in the rule is a set.
   932 
   933   - Higher order unification and forward proofs:
   934     The proof pattern
   935 
   936       have "P (S::'a set)" <...>
   937       then have "EX S. P S" ..
   938 
   939     no longer works (due to the incompleteness of the HO unification
   940     algorithm) and must be replaced by the pattern
   941 
   942       have "EX S. P S"
   943       proof
   944         show "P S" <...>
   945       qed
   946 
   947   - Calculational reasoning with subst (or similar rules):
   948     The proof pattern
   949 
   950       have "P (S::'a set)" <...>
   951       also have "S = T" <...>
   952       finally have "P T" .
   953 
   954     no longer works (for similar reasons as the previous example) and
   955     must be replaced by something like
   956 
   957       have "P (S::'a set)" <...>
   958       moreover have "S = T" <...>
   959       ultimately have "P T" by simp
   960 
   961   - Tactics or packages written in ML code:
   962     Code performing pattern matching on types via
   963 
   964       Type ("set", [T]) => ...
   965 
   966     must be rewritten. Moreover, functions like strip_type or
   967     binder_types no longer return the right value when applied to a
   968     type of the form
   969 
   970       T1 => ... => Tn => U => bool
   971 
   972     rather than
   973 
   974       T1 => ... => Tn => U set
   975 
   976 * Merged theories Wellfounded_Recursion, Accessible_Part and
   977 Wellfounded_Relations to theory Wellfounded.
   978 
   979 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   980 
   981 * Class finite no longer treats UNIV as class parameter.  Use class
   982 enum from theory Library/Enum instead to achieve a similar effect.
   983 INCOMPATIBILITY.
   984 
   985 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   986 and "Cons".  INCOMPATIBILITY.
   987 
   988 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   989 Potential INCOMPATIBILITY.
   990 
   991 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   992 injective_fst_snd removed, use split_eta and prod_eqI instead.
   993 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   994 
   995 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   996 the same name in theory Orderings:
   997 
   998   less_trans
   999   less_linear
  1000   le_imp_less_or_eq
  1001   le_less_trans
  1002   less_le_trans
  1003   less_not_sym
  1004   less_asym
  1005 
  1006 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1007 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1008 and different variable names.
  1009 
  1010 * Library/Option_ord.thy: Canonical order on option type.
  1011 
  1012 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1013 finite maps.
  1014 
  1015 * Library/Countable.thy: Type class for countable types.
  1016 
  1017 * Theory Int: The representation of numerals has changed.  The infix
  1018 operator BIT and the bit datatype with constructors B0 and B1 have
  1019 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1020 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1021 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1022 accordingly.
  1023 
  1024 * Theory Nat: definition of <= and < on natural numbers no longer
  1025 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1026 le_def and less_def have disappeared.  Consider lemmas not_less
  1027 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1028 
  1029 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1030 (whose purpose mainly is for various fold_set functionals) have been
  1031 abandoned in favor of the existing algebraic classes
  1032 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1033 lower_semilattice (resp. upper_semilattice) and linorder.
  1034 INCOMPATIBILITY.
  1035 
  1036 * Theory Transitive_Closure: induct and cases rules now declare proper
  1037 case_names ("base" and "step").  INCOMPATIBILITY.
  1038 
  1039 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1040 lattices.  The form set-specific version is available as
  1041 Inductive.lfp_ordinal_induct_set.
  1042 
  1043 * Renamed theorems "power.simps" to "power_int.simps".
  1044 INCOMPATIBILITY.
  1045 
  1046 * Class semiring_div provides basic abstract properties of semirings
  1047 with division and modulo operations.  Subsumes former class dvd_mod.
  1048 
  1049 * Merged theories IntDef, Numeral and IntArith into unified theory
  1050 Int.  INCOMPATIBILITY.
  1051 
  1052 * Theory Library/Code_Index: type "index" now represents natural
  1053 numbers rather than integers.  INCOMPATIBILITY.
  1054 
  1055 * New class "uminus" with operation "uminus" (split of from class
  1056 "minus" which now only has operation "minus", binary).
  1057 INCOMPATIBILITY.
  1058 
  1059 * Constants "card", "internal_split", "option_map" now with authentic
  1060 syntax.  INCOMPATIBILITY.
  1061 
  1062 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1063 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1064 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1065 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1066 Sup_set_def, le_def, less_def, option_map_def now with object
  1067 equality.  INCOMPATIBILITY.
  1068 
  1069 * Records. Removed K_record, and replaced it by pure lambda term
  1070 %x. c. The simplifier setup is now more robust against eta expansion.
  1071 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1072 
  1073 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1074 
  1075 * Library/ListVector: new theory of arithmetic vector operations.
  1076 
  1077 * Library/Order_Relation: new theory of various orderings as sets of
  1078 pairs.  Defines preorders, partial orders, linear orders and
  1079 well-orders on sets and on types.
  1080 
  1081 
  1082 *** ZF ***
  1083 
  1084 * Renamed some theories to allow to loading both ZF and HOL in the
  1085 same session:
  1086 
  1087   Datatype  -> Datatype_ZF
  1088   Inductive -> Inductive_ZF
  1089   Int       -> Int_ZF
  1090   IntDiv    -> IntDiv_ZF
  1091   Nat       -> Nat_ZF
  1092   List      -> List_ZF
  1093   Main      -> Main_ZF
  1094 
  1095 INCOMPATIBILITY: ZF theories that import individual theories below
  1096 Main might need to be adapted.  Regular theory Main is still
  1097 available, as trivial extension of Main_ZF.
  1098 
  1099 
  1100 *** ML ***
  1101 
  1102 * ML within Isar: antiquotation @{const name} or @{const
  1103 name(typargs)} produces statically-checked Const term.
  1104 
  1105 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1106 (of the same name).  Removed obsolete print command.
  1107 
  1108 * Removed obsolete "use_legacy_bindings" function.
  1109 
  1110 * The ``print mode'' is now a thread-local value derived from a global
  1111 template (the former print_mode reference), thus access becomes
  1112 non-critical.  The global print_mode reference is for session
  1113 management only; user-code should use print_mode_value,
  1114 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1115 
  1116 * Functions system/system_out provide a robust way to invoke external
  1117 shell commands, with propagation of interrupts (requires Poly/ML
  1118 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1119 
  1120 
  1121 *** System ***
  1122 
  1123 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1124 in accordance with Proof General 3.7, which prefers GNU emacs.
  1125 
  1126 * isatool tty runs Isabelle process with plain tty interaction;
  1127 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1128 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1129 
  1130 * isatool browser now works with Cygwin as well, using general
  1131 "javapath" function defined in Isabelle process environment.
  1132 
  1133 * YXML notation provides a simple and efficient alternative to
  1134 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1135 isatool yxml as described in the Isabelle system manual.
  1136 
  1137 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1138 provides general wrapper for managing an Isabelle process in a robust
  1139 fashion, with ``cooked'' output from stdin/stderr.
  1140 
  1141 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1142 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1143 
  1144 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1145 way of changing the user's settings is via
  1146 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1147 script.
  1148 
  1149 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1150 cores of the underlying machine, which is a good starting point for
  1151 optimal performance tuning.  The corresponding usedir option -M allows
  1152 "max" as an alias for "0".  WARNING: does not work on certain versions
  1153 of Mac OS (with Poly/ML 5.1).
  1154 
  1155 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1156 adverse effect of Isabelle flooding interactive front-ends (notably
  1157 ProofGeneral / XEmacs).
  1158 
  1159 
  1160 
  1161 New in Isabelle2007 (November 2007)
  1162 -----------------------------------
  1163 
  1164 *** General ***
  1165 
  1166 * More uniform information about legacy features, notably a
  1167 warning/error of "Legacy feature: ...", depending on the state of the
  1168 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1169 legacy features will disappear eventually.
  1170 
  1171 * Theory syntax: the header format ``theory A = B + C:'' has been
  1172 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1173 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1174 
  1175 * Theory syntax: the old non-Isar theory file format has been
  1176 discontinued altogether.  Note that ML proof scripts may still be used
  1177 with Isar theories; migration is usually quite simple with the ML
  1178 function use_legacy_bindings.  INCOMPATIBILITY.
  1179 
  1180 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1181 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1182 quotes.
  1183 
  1184 * Theory loader: be more serious about observing the static theory
  1185 header specifications (including optional directories), but not the
  1186 accidental file locations of previously successful loads.  The strict
  1187 update policy of former update_thy is now already performed by
  1188 use_thy, so the former has been removed; use_thys updates several
  1189 theories simultaneously, just as 'imports' within a theory header
  1190 specification, but without merging the results.  Potential
  1191 INCOMPATIBILITY: may need to refine theory headers and commands
  1192 ROOT.ML which depend on load order.
  1193 
  1194 * Theory loader: optional support for content-based file
  1195 identification, instead of the traditional scheme of full physical
  1196 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1197 (cf. the system manual).  The new scheme allows to work with
  1198 non-finished theories in persistent session images, such that source
  1199 files may be moved later on without requiring reloads.
  1200 
  1201 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1202 file (with the same base name as the theory) are considered a legacy
  1203 feature, which will disappear eventually. Even now, the theory loader
  1204 no longer maintains dependencies on such files.
  1205 
  1206 * Syntax: the scope for resolving ambiguities via type-inference is
  1207 now limited to individual terms, instead of whole simultaneous
  1208 specifications as before. This greatly reduces the complexity of the
  1209 syntax module and improves flexibility by separating parsing and
  1210 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1211 'fixes' etc.) are required in rare situations.
  1212 
  1213 * Syntax: constants introduced by new-style packages ('definition',
  1214 'abbreviation' etc.) are passed through the syntax module in
  1215 ``authentic mode''. This means that associated mixfix annotations
  1216 really stick to such constants, independently of potential name space
  1217 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1218 trees are represented slightly differently, may need to adapt syntax
  1219 translations accordingly. Use CONST marker in 'translations' and
  1220 @{const_syntax} antiquotation in 'parse_translation' etc.
  1221 
  1222 * Legacy goal package: reduced interface to the bare minimum required
  1223 to keep existing proof scripts running.  Most other user-level
  1224 functions are now part of the OldGoals structure, which is *not* open
  1225 by default (consider isatool expandshort before open OldGoals).
  1226 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1227 these tend to cause confusion about the actual goal (!) context being
  1228 used here, which is not necessarily the same as the_context().
  1229 
  1230 * Command 'find_theorems': supports "*" wild-card in "name:"
  1231 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1232 support a specific search form (see ProofGeneral/CHANGES).
  1233 
  1234 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1235 by default, which means that "prems" (and also "fixed variables") are
  1236 suppressed from proof state output.  Note that the ProofGeneral
  1237 settings mechanism allows to change and save options persistently, but
  1238 older versions of Isabelle will fail to start up if a negative prems
  1239 limit is imposed.
  1240 
  1241 * Local theory targets may be specified by non-nested blocks of
  1242 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1243 contain definitions, theorems etc., including any derived mechanism
  1244 that has been implemented on top of these primitives.  This concept
  1245 generalizes the existing ``theorem (in ...)'' towards more versatility
  1246 and scalability.
  1247 
  1248 * Proof General interface: proper undo of final 'end' command;
  1249 discontinued Isabelle/classic mode (ML proof scripts).
  1250 
  1251 
  1252 *** Document preparation ***
  1253 
  1254 * Added antiquotation @{theory name} which prints the given name,
  1255 after checking that it refers to a valid ancestor theory in the
  1256 current context.
  1257 
  1258 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1259 check the given source text as ML type/structure, printing verbatim.
  1260 
  1261 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1262 "c args == rhs" given in the current context.  (Any number of
  1263 arguments may be given on the LHS.)
  1264 
  1265 
  1266 *** Pure ***
  1267 
  1268 * The 'class' package offers a combination of axclass and locale to
  1269 achieve Haskell-like type classes in Isabelle.  Definitions and
  1270 theorems within a class context produce both relative results (with
  1271 implicit parameters according to the locale context), and polymorphic
  1272 constants with qualified polymorphism (according to the class
  1273 context).  Within the body context of a 'class' target, a separate
  1274 syntax layer ("user space type system") takes care of converting
  1275 between global polymorphic consts and internal locale representation.
  1276 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1277 "isatool doc classes" provides a tutorial.
  1278 
  1279 * Generic code generator framework allows to generate executable
  1280 code for ML and Haskell (including Isabelle classes).  A short usage
  1281 sketch:
  1282 
  1283     internal compilation:
  1284         export_code <list of constants (term syntax)> in SML
  1285     writing SML code to a file:
  1286         export_code <list of constants (term syntax)> in SML <filename>
  1287     writing OCaml code to a file:
  1288         export_code <list of constants (term syntax)> in OCaml <filename>
  1289     writing Haskell code to a bunch of files:
  1290         export_code <list of constants (term syntax)> in Haskell <filename>
  1291 
  1292     evaluating closed propositions to True/False using code generation:
  1293         method ``eval''
  1294 
  1295 Reasonable default setup of framework in HOL.
  1296 
  1297 Theorem attributs for selecting and transforming function equations theorems:
  1298 
  1299     [code fun]:        select a theorem as function equation for a specific constant
  1300     [code fun del]:    deselect a theorem as function equation for a specific constant
  1301     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1302     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1303 
  1304 User-defined serializations (target in {SML, OCaml, Haskell}):
  1305 
  1306     code_const <and-list of constants (term syntax)>
  1307       {(target) <and-list of const target syntax>}+
  1308 
  1309     code_type <and-list of type constructors>
  1310       {(target) <and-list of type target syntax>}+
  1311 
  1312     code_instance <and-list of instances>
  1313       {(target)}+
  1314         where instance ::= <type constructor> :: <class>
  1315 
  1316     code_class <and_list of classes>
  1317       {(target) <and-list of class target syntax>}+
  1318         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1319 
  1320 code_instance and code_class only are effective to target Haskell.
  1321 
  1322 For example usage see src/HOL/ex/Codegenerator.thy and
  1323 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1324 generation from Isabelle/HOL theories is available via "isatool doc
  1325 codegen".
  1326 
  1327 * Code generator: consts in 'consts_code' Isar commands are now
  1328 referred to by usual term syntax (including optional type
  1329 annotations).
  1330 
  1331 * Command 'no_translations' removes translation rules from theory
  1332 syntax.
  1333 
  1334 * Overloaded definitions are now actually checked for acyclic
  1335 dependencies.  The overloading scheme is slightly more general than
  1336 that of Haskell98, although Isabelle does not demand an exact
  1337 correspondence to type class and instance declarations.
  1338 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1339 exotic versions of overloading -- at the discretion of the user!
  1340 
  1341 Polymorphic constants are represented via type arguments, i.e. the
  1342 instantiation that matches an instance against the most general
  1343 declaration given in the signature.  For example, with the declaration
  1344 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1345 as c(nat).  Overloading is essentially simultaneous structural
  1346 recursion over such type arguments.  Incomplete specification patterns
  1347 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1348 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1349 Command 'print_theory' outputs the normalized system of recursive
  1350 equations, see section "definitions".
  1351 
  1352 * Configuration options are maintained within the theory or proof
  1353 context (with name and type bool/int/string), providing a very simple
  1354 interface to a poor-man's version of general context data.  Tools may
  1355 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1356 these values using Config.get etc.  Users may change options via an
  1357 associated attribute of the same name.  This form of context
  1358 declaration works particularly well with commands 'declare' or
  1359 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1360 very easy to avoid global references, which would not observe Isar
  1361 toplevel undo/redo and fail to work with multithreading.
  1362 
  1363 Various global ML references of Pure and HOL have been turned into
  1364 configuration options:
  1365 
  1366   Unify.search_bound		unify_search_bound
  1367   Unify.trace_bound		unify_trace_bound
  1368   Unify.trace_simp		unify_trace_simp
  1369   Unify.trace_types		unify_trace_types
  1370   Simplifier.simp_depth_limit	simp_depth_limit
  1371   Blast.depth_limit		blast_depth_limit
  1372   DatatypeProp.dtK		datatype_distinctness_limit
  1373   fast_arith_neq_limit  	fast_arith_neq_limit
  1374   fast_arith_split_limit	fast_arith_split_limit
  1375 
  1376 * Named collections of theorems may be easily installed as context
  1377 data using the functor NamedThmsFun (see also
  1378 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1379 attributes; there is also a toplevel print command.  This facility is
  1380 just a common case of general context data, which is the preferred way
  1381 for anything more complex than just a list of facts in canonical
  1382 order.
  1383 
  1384 * Isar: command 'declaration' augments a local theory by generic
  1385 declaration functions written in ML.  This enables arbitrary content
  1386 being added to the context, depending on a morphism that tells the
  1387 difference of the original declaration context wrt. the application
  1388 context encountered later on.
  1389 
  1390 * Isar: proper interfaces for simplification procedures.  Command
  1391 'simproc_setup' declares named simprocs (with match patterns, and body
  1392 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1393 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1394 
  1395 * Isar: an extra pair of brackets around attribute declarations
  1396 abbreviates a theorem reference involving an internal dummy fact,
  1397 which will be ignored later --- only the effect of the attribute on
  1398 the background context will persist.  This form of in-place
  1399 declarations is particularly useful with commands like 'declare' and
  1400 'using', for example ``have A using [[simproc a]] by simp''.
  1401 
  1402 * Isar: method "assumption" (and implicit closing of subproofs) now
  1403 takes simple non-atomic goal assumptions into account: after applying
  1404 an assumption as a rule the resulting subgoals are solved by atomic
  1405 assumption steps.  This is particularly useful to finish 'obtain'
  1406 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1407 without referring to the original premise "!!x. P x ==> thesis" in the
  1408 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1409 more permissive.
  1410 
  1411 * Isar: implicit use of prems from the Isar proof context is
  1412 considered a legacy feature.  Common applications like ``have A .''
  1413 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1414 referencing facts explicitly here improves readability and
  1415 maintainability of proof texts.
  1416 
  1417 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1418 the obtained context from the course of reasoning!  For example:
  1419 
  1420   assume "EX x y. A x & B y"   -- "any previous fact"
  1421   then guess x and y by clarify
  1422 
  1423 This technique is potentially adventurous, depending on the facts and
  1424 proof tools being involved here.
  1425 
  1426 * Isar: known facts from the proof context may be specified as literal
  1427 propositions, using ASCII back-quote syntax.  This works wherever
  1428 named facts used to be allowed so far, in proof commands, proof
  1429 methods, attributes etc.  Literal facts are retrieved from the context
  1430 according to unification of type and term parameters.  For example,
  1431 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1432 theorems in the current context, then these are valid literal facts:
  1433 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1434 
  1435 There is also a proof method "fact" which does the same composition
  1436 for explicit goal states, e.g. the following proof texts coincide with
  1437 certain special cases of literal facts:
  1438 
  1439   have "A" by fact                 ==  note `A`
  1440   have "A ==> B" by fact           ==  note `A ==> B`
  1441   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1442   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1443 
  1444 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1445 outer syntax.  Thus symbolic identifiers may be used without
  1446 additional white space in declarations like this: ``assume *: A''.
  1447 
  1448 * Isar: 'print_facts' prints all local facts of the current context,
  1449 both named and unnamed ones.
  1450 
  1451 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1452 
  1453   def x == "t" and y == "u"
  1454 
  1455 * Isar: added command 'unfolding', which is structurally similar to
  1456 'using', but affects both the goal state and facts by unfolding given
  1457 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1458 'unfolded' attribute may be replaced by first-class proof text.
  1459 
  1460 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1461 and command 'unfolding' now all support object-level equalities
  1462 (potentially conditional).  The underlying notion of rewrite rule is
  1463 analogous to the 'rule_format' attribute, but *not* that of the
  1464 Simplifier (which is usually more generous).
  1465 
  1466 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1467 premises of a theorem by n. Useful in conjunction with drule.
  1468 
  1469 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1470 method expression within a sandbox consisting of the first N
  1471 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1472 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1473 simplifies all new goals that emerge from applying rule foo to the
  1474 originally first one.
  1475 
  1476 * Isar: schematic goals are no longer restricted to higher-order
  1477 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1478 expected.
  1479 
  1480 * Isar: the conclusion of a long theorem statement is now either
  1481 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1482 (essentially a disjunction of cases with local parameters and
  1483 assumptions).  The latter allows to express general elimination rules
  1484 adequately; in this notation common elimination rules look like this:
  1485 
  1486   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1487     assumes "EX x. P x"
  1488     obtains x where "P x"
  1489 
  1490   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1491     assumes "A & B"
  1492     obtains A and B
  1493 
  1494   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1495     assumes "A | B"
  1496     obtains
  1497       A
  1498     | B
  1499 
  1500 The subsequent classical rules even refer to the formal "thesis"
  1501 explicitly:
  1502 
  1503   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1504     obtains "~ thesis"
  1505 
  1506   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1507     obtains "thesis ==> something"
  1508 
  1509 The actual proof of an 'obtains' statement is analogous to that of the
  1510 Isar proof element 'obtain', only that there may be several cases.
  1511 Optional case names may be specified in parentheses; these will be
  1512 available both in the present proof and as annotations in the
  1513 resulting rule, for later use with the 'cases' method (cf. attribute
  1514 case_names).
  1515 
  1516 * Isar: the assumptions of a long theorem statement are available as
  1517 "assms" fact in the proof context.  This is more appropriate than the
  1518 (historical) "prems", which refers to all assumptions of the current
  1519 context, including those from the target locale, proof body etc.
  1520 
  1521 * Isar: 'print_statement' prints theorems from the current theory or
  1522 proof context in long statement form, according to the syntax of a
  1523 top-level lemma.
  1524 
  1525 * Isar: 'obtain' takes an optional case name for the local context
  1526 introduction rule (default "that").
  1527 
  1528 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1529 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1530 to occur.
  1531 
  1532 * Pure: syntax "CONST name" produces a fully internalized constant
  1533 according to the current context.  This is particularly useful for
  1534 syntax translations that should refer to internal constant
  1535 representations independently of name spaces.
  1536 
  1537 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1538 instead of "FOO ". This allows multiple binder declarations to coexist
  1539 in the same context.  INCOMPATIBILITY.
  1540 
  1541 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1542 primitive that also works in a locale context (both for constants and
  1543 fixed variables). Type declaration and internal syntactic representation
  1544 of given constants retrieved from the context. Likewise, the
  1545 'no_notation' command allows to remove given syntax annotations from the
  1546 current context.
  1547 
  1548 * Isar/locales: new derived specification elements 'axiomatization',
  1549 'definition', 'abbreviation', which support type-inference, admit
  1550 object-level specifications (equality, equivalence).  See also the
  1551 isar-ref manual.  Examples:
  1552 
  1553   axiomatization
  1554     eq  (infix "===" 50) where
  1555     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1556 
  1557   definition "f x y = x + y + 1"
  1558   definition g where "g x = f x x"
  1559 
  1560   abbreviation
  1561     neq  (infix "=!=" 50) where
  1562     "x =!= y == ~ (x === y)"
  1563 
  1564 These specifications may be also used in a locale context.  Then the
  1565 constants being introduced depend on certain fixed parameters, and the
  1566 constant name is qualified by the locale base name.  An internal
  1567 abbreviation takes care for convenient input and output, making the
  1568 parameters implicit and using the original short name.  See also
  1569 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1570 entities from a monomorphic theory.
  1571 
  1572 Presently, abbreviations are only available 'in' a target locale, but
  1573 not inherited by general import expressions.  Also note that
  1574 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1575 'translations' in common applications.  The "no_abbrevs" print mode
  1576 prevents folding of abbreviations in term output.
  1577 
  1578 Concrete syntax is attached to specified constants in internal form,
  1579 independently of name spaces.  The parse tree representation is
  1580 slightly different -- use 'notation' instead of raw 'syntax', and
  1581 'translations' with explicit "CONST" markup to accommodate this.
  1582 
  1583 * Pure/Isar: unified syntax for new-style specification mechanisms
  1584 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1585 full type inference and dummy patterns ("_").  For example:
  1586 
  1587   definition "K x _ = x"
  1588 
  1589   inductive conj for A B
  1590   where "A ==> B ==> conj A B"
  1591 
  1592 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1593 the current context.  Print mode "no_abbrevs" prevents inversion of
  1594 abbreviations on output.
  1595 
  1596 * Isar/locales: improved parameter handling: use of locales "var" and
  1597 "struct" no longer necessary; - parameter renamings are no longer
  1598 required to be injective.  For example, this allows to define
  1599 endomorphisms as locale endom = homom mult mult h.
  1600 
  1601 * Isar/locales: changed the way locales with predicates are defined.
  1602 Instead of accumulating the specification, the imported expression is
  1603 now an interpretation.  INCOMPATIBILITY: different normal form of
  1604 locale expressions.  In particular, in interpretations of locales with
  1605 predicates, goals repesenting already interpreted fragments are not
  1606 removed automatically.  Use methods `intro_locales' and
  1607 `unfold_locales'; see below.
  1608 
  1609 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1610 provide backward reasoning on locales predicates.  The methods are
  1611 aware of interpretations and discharge corresponding goals.
  1612 `intro_locales' is less aggressive then `unfold_locales' and does not
  1613 unfold predicates to assumptions.
  1614 
  1615 * Isar/locales: the order in which locale fragments are accumulated
  1616 has changed.  This enables to override declarations from fragments due
  1617 to interpretations -- for example, unwanted simp rules.
  1618 
  1619 * Isar/locales: interpretation in theories and proof contexts has been
  1620 extended.  One may now specify (and prove) equations, which are
  1621 unfolded in interpreted theorems.  This is useful for replacing
  1622 defined concepts (constants depending on locale parameters) by
  1623 concepts already existing in the target context.  Example:
  1624 
  1625   interpretation partial_order ["op <= :: [int, int] => bool"]
  1626     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1627 
  1628 Typically, the constant `partial_order.less' is created by a
  1629 definition specification element in the context of locale
  1630 partial_order.
  1631 
  1632 * Method "induct": improved internal context management to support
  1633 local fixes and defines on-the-fly. Thus explicit meta-level
  1634 connectives !!  and ==> are rarely required anymore in inductive goals
  1635 (using object-logic connectives for this purpose has been long
  1636 obsolete anyway). Common proof patterns are explained in
  1637 src/HOL/Induct/Common_Patterns.thy, see also
  1638 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1639 examples.
  1640 
  1641 * Method "induct": improved handling of simultaneous goals. Instead of
  1642 introducing object-level conjunction, the statement is now split into
  1643 several conclusions, while the corresponding symbolic cases are nested
  1644 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1645 see src/HOL/Induct/Common_Patterns.thy, for example.
  1646 
  1647 * Method "induct": mutual induction rules are now specified as a list
  1648 of rule sharing the same induction cases. HOL packages usually provide
  1649 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1650 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1651 mutual induction rules differently, i.e. like this:
  1652 
  1653   (induct rule: foo_bar.inducts)
  1654   (induct set: foo bar)
  1655   (induct pred: foo bar)
  1656   (induct type: foo bar)
  1657 
  1658 The ML function ProjectRule.projections turns old-style rules into the
  1659 new format.
  1660 
  1661 * Method "coinduct": dual of induction, see
  1662 src/HOL/Library/Coinductive_List.thy for various examples.
  1663 
  1664 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1665 considered a legacy feature.
  1666 
  1667 * Attribute "symmetric" produces result with standardized schematic
  1668 variables (index 0).  Potential INCOMPATIBILITY.
  1669 
  1670 * Simplifier: by default the simplifier trace only shows top level
  1671 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1672 default. Thus there is less danger of being flooded by the trace. The
  1673 trace indicates where parts have been suppressed.
  1674   
  1675 * Provers/classical: removed obsolete classical version of elim_format
  1676 attribute; classical elim/dest rules are now treated uniformly when
  1677 manipulating the claset.
  1678 
  1679 * Provers/classical: stricter checks to ensure that supplied intro,
  1680 dest and elim rules are well-formed; dest and elim rules must have at
  1681 least one premise.
  1682 
  1683 * Provers/classical: attributes dest/elim/intro take an optional
  1684 weight argument for the rule (just as the Pure versions).  Weights are
  1685 ignored by automated tools, but determine the search order of single
  1686 rule steps.
  1687 
  1688 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1689 where the body does not mention the bound variable.  Note that dummy
  1690 patterns implicitly depend on their context of bounds, which makes
  1691 "{_. _}" match any set comprehension as expected.  Potential
  1692 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1693 constant "_idtdummy" in the binding position.
  1694 
  1695 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1696 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1697 for example "A -> B" => "Pi A (%_. B)".
  1698 
  1699 * Pure: 'class_deps' command visualizes the subclass relation, using
  1700 the graph browser tool.
  1701 
  1702 * Pure: 'print_theory' now suppresses certain internal declarations by
  1703 default; use '!' option for full details.
  1704 
  1705 
  1706 *** HOL ***
  1707 
  1708 * Method "metis" proves goals by applying the Metis general-purpose
  1709 resolution prover (see also http://gilith.com/software/metis/).
  1710 Examples are in the directory MetisExamples.  WARNING: the
  1711 Isabelle/HOL-Metis integration does not yet work properly with
  1712 multi-threading.
  1713   
  1714 * Command 'sledgehammer' invokes external automatic theorem provers as
  1715 background processes.  It generates calls to the "metis" method if
  1716 successful. These can be pasted into the proof.  Users do not have to
  1717 wait for the automatic provers to return.  WARNING: does not really
  1718 work with multi-threading.
  1719 
  1720 * New "auto_quickcheck" feature tests outermost goal statements for
  1721 potential counter-examples.  Controlled by ML references
  1722 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1723 5000 milliseconds).  Fails silently if statements is outside of
  1724 executable fragment, or any other codgenerator problem occurs.
  1725 
  1726 * New constant "undefined" with axiom "undefined x = undefined".
  1727 
  1728 * Added class "HOL.eq", allowing for code generation with polymorphic
  1729 equality.
  1730 
  1731 * Some renaming of class constants due to canonical name prefixing in
  1732 the new 'class' package:
  1733 
  1734     HOL.abs ~> HOL.abs_class.abs
  1735     HOL.divide ~> HOL.divide_class.divide
  1736     0 ~> HOL.zero_class.zero
  1737     1 ~> HOL.one_class.one
  1738     op + ~> HOL.plus_class.plus
  1739     op - ~> HOL.minus_class.minus
  1740     uminus ~> HOL.minus_class.uminus
  1741     op * ~> HOL.times_class.times
  1742     op < ~> HOL.ord_class.less
  1743     op <= > HOL.ord_class.less_eq
  1744     Nat.power ~> Power.power_class.power
  1745     Nat.size ~> Nat.size_class.size
  1746     Numeral.number_of ~> Numeral.number_class.number_of
  1747     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1748     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1749     Orderings.min ~> Orderings.ord_class.min
  1750     Orderings.max ~> Orderings.ord_class.max
  1751     Divides.op div ~> Divides.div_class.div
  1752     Divides.op mod ~> Divides.div_class.mod
  1753     Divides.op dvd ~> Divides.div_class.dvd
  1754 
  1755 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1756 
  1757 a) User-defined constants using any of the names "plus", "minus",
  1758 "times", "less" or "less_eq". The standard syntax translations for
  1759 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1760 names.
  1761 
  1762 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1763 INCOMPATIBILITY: use more specific names.
  1764 
  1765 c) Permutative equations (e.g. "a + b = b + a")
  1766 Since the change of names also changes the order of terms, permutative
  1767 rewrite rules may get applied in a different order. Experience shows
  1768 that this is rarely the case (only two adaptions in the whole Isabelle
  1769 distribution).  INCOMPATIBILITY: rewrite proofs
  1770 
  1771 d) ML code directly refering to constant names
  1772 This in general only affects hand-written proof tactics, simprocs and
  1773 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1774 Consider using @{const_name} antiquotation.
  1775 
  1776 * New class "default" with associated constant "default".
  1777 
  1778 * Function "sgn" is now overloaded and available on int, real, complex
  1779 (and other numeric types), using class "sgn".  Two possible defs of
  1780 sgn are given as equational assumptions in the classes sgn_if and
  1781 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1782 INCOMPATIBILITY.
  1783 
  1784 * Locale "partial_order" now unified with class "order" (cf. theory
  1785 Orderings), added parameter "less".  INCOMPATIBILITY.
  1786 
  1787 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1788 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1789 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1790 
  1791 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1792 changed order of proof goals in instance proofs.
  1793 
  1794 * The transitivity reasoner for partial and linear orders is set up
  1795 for classes "order" and "linorder".  Instances of the reasoner are available
  1796 in all contexts importing or interpreting the corresponding locales.
  1797 Method "order" invokes the reasoner separately; the reasoner
  1798 is also integrated with the Simplifier as a solver.  Diagnostic
  1799 command 'print_orders' shows the available instances of the reasoner
  1800 in the current context.
  1801 
  1802 * Localized monotonicity predicate in theory "Orderings"; integrated
  1803 lemmas max_of_mono and min_of_mono with this predicate.
  1804 INCOMPATIBILITY.
  1805 
  1806 * Formulation of theorem "dense" changed slightly due to integration
  1807 with new class dense_linear_order.
  1808 
  1809 * Uniform lattice theory development in HOL.
  1810 
  1811     constants "meet" and "join" now named "inf" and "sup"
  1812     constant "Meet" now named "Inf"
  1813 
  1814     classes "meet_semilorder" and "join_semilorder" now named
  1815       "lower_semilattice" and "upper_semilattice"
  1816     class "lorder" now named "lattice"
  1817     class "comp_lat" now named "complete_lattice"
  1818 
  1819     Instantiation of lattice classes allows explicit definitions
  1820     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1821 
  1822   INCOMPATIBILITY.  Theorem renames:
  1823 
  1824     meet_left_le            ~> inf_le1
  1825     meet_right_le           ~> inf_le2
  1826     join_left_le            ~> sup_ge1
  1827     join_right_le           ~> sup_ge2
  1828     meet_join_le            ~> inf_sup_ord
  1829     le_meetI                ~> le_infI
  1830     join_leI                ~> le_supI
  1831     le_meet                 ~> le_inf_iff
  1832     le_join                 ~> ge_sup_conv
  1833     meet_idempotent         ~> inf_idem
  1834     join_idempotent         ~> sup_idem
  1835     meet_comm               ~> inf_commute
  1836     join_comm               ~> sup_commute
  1837     meet_leI1               ~> le_infI1
  1838     meet_leI2               ~> le_infI2
  1839     le_joinI1               ~> le_supI1
  1840     le_joinI2               ~> le_supI2
  1841     meet_assoc              ~> inf_assoc
  1842     join_assoc              ~> sup_assoc
  1843     meet_left_comm          ~> inf_left_commute
  1844     meet_left_idempotent    ~> inf_left_idem
  1845     join_left_comm          ~> sup_left_commute
  1846     join_left_idempotent    ~> sup_left_idem
  1847     meet_aci                ~> inf_aci
  1848     join_aci                ~> sup_aci
  1849     le_def_meet             ~> le_iff_inf
  1850     le_def_join             ~> le_iff_sup
  1851     join_absorp2            ~> sup_absorb2
  1852     join_absorp1            ~> sup_absorb1
  1853     meet_absorp1            ~> inf_absorb1
  1854     meet_absorp2            ~> inf_absorb2
  1855     meet_join_absorp        ~> inf_sup_absorb
  1856     join_meet_absorp        ~> sup_inf_absorb
  1857     distrib_join_le         ~> distrib_sup_le
  1858     distrib_meet_le         ~> distrib_inf_le
  1859 
  1860     add_meet_distrib_left   ~> add_inf_distrib_left
  1861     add_join_distrib_left   ~> add_sup_distrib_left
  1862     is_join_neg_meet        ~> is_join_neg_inf
  1863     is_meet_neg_join        ~> is_meet_neg_sup
  1864     add_meet_distrib_right  ~> add_inf_distrib_right
  1865     add_join_distrib_right  ~> add_sup_distrib_right
  1866     add_meet_join_distribs  ~> add_sup_inf_distribs
  1867     join_eq_neg_meet        ~> sup_eq_neg_inf
  1868     meet_eq_neg_join        ~> inf_eq_neg_sup
  1869     add_eq_meet_join        ~> add_eq_inf_sup
  1870     meet_0_imp_0            ~> inf_0_imp_0
  1871     join_0_imp_0            ~> sup_0_imp_0
  1872     meet_0_eq_0             ~> inf_0_eq_0
  1873     join_0_eq_0             ~> sup_0_eq_0
  1874     neg_meet_eq_join        ~> neg_inf_eq_sup
  1875     neg_join_eq_meet        ~> neg_sup_eq_inf
  1876     join_eq_if              ~> sup_eq_if
  1877 
  1878     mono_meet               ~> mono_inf
  1879     mono_join               ~> mono_sup
  1880     meet_bool_eq            ~> inf_bool_eq
  1881     join_bool_eq            ~> sup_bool_eq
  1882     meet_fun_eq             ~> inf_fun_eq
  1883     join_fun_eq             ~> sup_fun_eq
  1884     meet_set_eq             ~> inf_set_eq
  1885     join_set_eq             ~> sup_set_eq
  1886     meet1_iff               ~> inf1_iff
  1887     meet2_iff               ~> inf2_iff
  1888     meet1I                  ~> inf1I
  1889     meet2I                  ~> inf2I
  1890     meet1D1                 ~> inf1D1
  1891     meet2D1                 ~> inf2D1
  1892     meet1D2                 ~> inf1D2
  1893     meet2D2                 ~> inf2D2
  1894     meet1E                  ~> inf1E
  1895     meet2E                  ~> inf2E
  1896     join1_iff               ~> sup1_iff
  1897     join2_iff               ~> sup2_iff
  1898     join1I1                 ~> sup1I1
  1899     join2I1                 ~> sup2I1
  1900     join1I1                 ~> sup1I1
  1901     join2I2                 ~> sup1I2
  1902     join1CI                 ~> sup1CI
  1903     join2CI                 ~> sup2CI
  1904     join1E                  ~> sup1E
  1905     join2E                  ~> sup2E
  1906 
  1907     is_meet_Meet            ~> is_meet_Inf
  1908     Meet_bool_def           ~> Inf_bool_def
  1909     Meet_fun_def            ~> Inf_fun_def
  1910     Meet_greatest           ~> Inf_greatest
  1911     Meet_lower              ~> Inf_lower
  1912     Meet_set_def            ~> Inf_set_def
  1913 
  1914     Sup_def                 ~> Sup_Inf
  1915     Sup_bool_eq             ~> Sup_bool_def
  1916     Sup_fun_eq              ~> Sup_fun_def
  1917     Sup_set_eq              ~> Sup_set_def
  1918 
  1919     listsp_meetI            ~> listsp_infI
  1920     listsp_meet_eq          ~> listsp_inf_eq
  1921 
  1922     meet_min                ~> inf_min
  1923     join_max                ~> sup_max
  1924 
  1925 * Added syntactic class "size"; overloaded constant "size" now has
  1926 type "'a::size ==> bool"
  1927 
  1928 * Internal reorganisation of `size' of datatypes: size theorems
  1929 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1930 simplification rules by default!); theorems "prod.size" now named
  1931 "*.size".
  1932 
  1933 * Class "div" now inherits from class "times" rather than "type".
  1934 INCOMPATIBILITY.
  1935 
  1936 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1937 Linorder etc.  have disappeared; operations defined in terms of
  1938 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1939 
  1940 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1941 
  1942 * HOL-Word: New extensive library and type for generic, fixed size
  1943 machine words, with arithemtic, bit-wise, shifting and rotating
  1944 operations, reflection into int, nat, and bool lists, automation for
  1945 linear arithmetic (by automatic reflection into nat or int), including
  1946 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1947 arithmetic type classes, supporting automatic simplification of
  1948 numerals on all operations.
  1949 
  1950 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1951 
  1952 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1953 
  1954 * Code generator library theories:
  1955   - Code_Integer represents HOL integers by big integer literals in target
  1956     languages.
  1957   - Code_Char represents HOL characters by character literals in target
  1958     languages.
  1959   - Code_Char_chr like Code_Char, but also offers treatment of character
  1960     codes; includes Code_Integer.
  1961   - Executable_Set allows to generate code for finite sets using lists.
  1962   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1963     denominator).
  1964   - Executable_Real implements a subset of real numbers, namly those
  1965     representable by rational numbers.
  1966   - Efficient_Nat implements natural numbers by integers, which in general will
  1967     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1968     includes Code_Integer.
  1969   - Code_Index provides an additional datatype index which is mapped to
  1970     target-language built-in integers.
  1971   - Code_Message provides an additional datatype message_string which is isomorphic to
  1972     strings; messages are mapped to target-language strings.
  1973 
  1974 * New package for inductive predicates
  1975 
  1976   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1977 
  1978     inductive
  1979       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1980       for z_1 :: U_1 and ... and z_n :: U_m
  1981     where
  1982       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1983     | ...
  1984 
  1985   with full support for type-inference, rather than
  1986 
  1987     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1988 
  1989     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1990     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1991 
  1992     inductive "s z_1 ... z_m"
  1993     intros
  1994       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1995       ...
  1996 
  1997   For backward compatibility, there is a wrapper allowing inductive
  1998   sets to be defined with the new package via
  1999 
  2000     inductive_set
  2001       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2002       for z_1 :: U_1 and ... and z_n :: U_m
  2003     where
  2004       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2005     | ...
  2006 
  2007   or
  2008 
  2009     inductive_set
  2010       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2011       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2012       for z_1 :: U_1 and ... and z_n :: U_m
  2013     where
  2014       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2015     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2016     | ...
  2017 
  2018   if the additional syntax "p ..." is required.
  2019 
  2020   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2021   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2022 
  2023   INCOMPATIBILITIES:
  2024 
  2025   - Since declaration and definition of inductive sets or predicates
  2026     is no longer separated, abbreviations involving the newly
  2027     introduced sets or predicates must be specified together with the
  2028     introduction rules after the 'where' keyword (see above), rather
  2029     than before the actual inductive definition.
  2030 
  2031   - The variables in induction and elimination rules are now
  2032     quantified in the order of their occurrence in the introduction
  2033     rules, rather than in alphabetical order. Since this may break
  2034     some proofs, these proofs either have to be repaired, e.g. by
  2035     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2036     statements of the form
  2037 
  2038       case (rule_i a_i_1 ... a_i_{k_i})
  2039 
  2040     or the old order of quantification has to be restored by explicitly adding
  2041     meta-level quantifiers in the introduction rules, i.e.
  2042 
  2043       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2044 
  2045   - The format of the elimination rules is now
  2046 
  2047       p z_1 ... z_m x_1 ... x_n ==>
  2048         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2049         ==> ... ==> P
  2050 
  2051     for predicates and
  2052 
  2053       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2054         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2055         ==> ... ==> P
  2056 
  2057     for sets rather than
  2058 
  2059       x : s z_1 ... z_m ==>
  2060         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2061         ==> ... ==> P
  2062 
  2063     This may require terms in goals to be expanded to n-tuples
  2064     (e.g. using case_tac or simplification with the split_paired_all
  2065     rule) before the above elimination rule is applicable.
  2066 
  2067   - The elimination or case analysis rules for (mutually) inductive
  2068     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2069     list of rules "p_1_..._p_k.elims" is no longer available.
  2070 
  2071 * New package "function"/"fun" for general recursive functions,
  2072 supporting mutual and nested recursion, definitions in local contexts,
  2073 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2074 for small examples, and the separate tutorial on the function
  2075 package. The old recdef "package" is still available as before, but
  2076 users are encouraged to use the new package.
  2077 
  2078 * Method "lexicographic_order" automatically synthesizes termination
  2079 relations as lexicographic combinations of size measures. 
  2080 
  2081 * Case-expressions allow arbitrary constructor-patterns (including
  2082 "_") and take their order into account, like in functional
  2083 programming.  Internally, this is translated into nested
  2084 case-expressions; missing cases are added and mapped to the predefined
  2085 constant "undefined". In complicated cases printing may no longer show
  2086 the original input but the internal form. Lambda-abstractions allow
  2087 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2088 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2089 variable.
  2090 
  2091 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2092 is an abbreviation for "of_nat :: nat => int". The simplification
  2093 rules for "of_nat" have been changed to work like "int" did
  2094 previously.  Potential INCOMPATIBILITY:
  2095   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2096   - of_nat_diff and of_nat_mult are no longer default simp rules
  2097 
  2098 * Method "algebra" solves polynomial equations over (semi)rings using
  2099 Groebner bases. The (semi)ring structure is defined by locales and the
  2100 tool setup depends on that generic context. Installing the method for
  2101 a specific type involves instantiating the locale and possibly adding
  2102 declarations for computation on the coefficients.  The method is
  2103 already instantiated for natural numbers and for the axiomatic class
  2104 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2105 CALCULEMUS 2007 for the general principles underlying this
  2106 architecture of context-aware proof-tools.
  2107 
  2108 * Method "ferrack" implements quantifier elimination over
  2109 special-purpose dense linear orders using locales (analogous to
  2110 "algebra"). The method is already installed for class
  2111 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2112 rat, etc.
  2113 
  2114 * Former constant "List.op @" now named "List.append".  Use ML
  2115 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2116 circumvent possible incompatibilities when working on ML level.
  2117 
  2118 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2119 
  2120 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2121 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2122 
  2123 * New syntax for Haskell-like list comprehension (input only), eg.
  2124 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2125 
  2126 * The special syntax for function "filter" has changed from [x :
  2127 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2128 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2129 
  2130 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2131 defined on nat only, as an abbreviation for [a..<Suc b]
  2132 INCOMPATIBILITY.
  2133 
  2134 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2135 
  2136 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2137 
  2138 * New lemma collection field_simps (an extension of ring_simps) for
  2139 manipulating (in)equations involving division. Multiplies with all
  2140 denominators that can be proved to be non-zero (in equations) or
  2141 positive/negative (in inequations).
  2142 
  2143 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2144 have been improved and renamed to ring_simps, group_simps and
  2145 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2146 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2147 
  2148 * Theory Library/Commutative_Ring: switched from recdef to function
  2149 package; constants add, mul, pow now curried.  Infix syntax for
  2150 algebraic operations.
  2151 
  2152 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2153 INCOMPATIBILITY.
  2154 
  2155 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2156 INCOMPATIBILITY.
  2157 
  2158 * HOL/records: generalised field-update to take a function on the
  2159 field rather than the new value: r(|A := x|) is translated to A_update
  2160 (K x) r The K-combinator that is internally used is called K_record.
  2161 INCOMPATIBILITY: Usage of the plain update functions has to be
  2162 adapted.
  2163  
  2164 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2165 * x = 0, which are required for a semiring.  Richer structures do not
  2166 inherit from semiring_0 anymore, because this property is a theorem
  2167 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2168 there is more to prove, but this is mostly trivial.
  2169 
  2170 * Class "recpower" is generalized to arbitrary monoids, not just
  2171 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2172 commutativity or semiring properties additionally.
  2173 
  2174 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2175 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2176 better use 'abbreviation'.
  2177 
  2178 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2179 
  2180 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2181 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2182 significant changes for setting up numeral syntax for types:
  2183   - New constants Numeral.pred and Numeral.succ instead
  2184       of former Numeral.bin_pred and Numeral.bin_succ.
  2185   - Use integer operations instead of bin_add, bin_mult and so on.
  2186   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2187   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2188 
  2189 See src/HOL/Integ/IntArith.thy for an example setup.
  2190 
  2191 * Command 'normal_form' computes the normal form of a term that may
  2192 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2193 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2194 heavy-duty computations because the functions are compiled to ML
  2195 first.  Correspondingly, a method "normalization" is provided.  See
  2196 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2197 
  2198 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2199 25 like -->); output depends on the "iff" print_mode, the default is
  2200 "A = B" (with priority 50).
  2201 
  2202 * Relations less (<) and less_eq (<=) are also available on type bool.
  2203 Modified syntax to disallow nesting without explicit parentheses,
  2204 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2205 INCOMPATIBILITY.
  2206 
  2207 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2208 
  2209 * Relation composition operator "op O" now has precedence 75 and binds
  2210 stronger than union and intersection. INCOMPATIBILITY.
  2211 
  2212 * The old set interval syntax "{m..n(}" (and relatives) has been
  2213 removed.  Use "{m..<n}" (and relatives) instead.
  2214 
  2215 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2216 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2217 ``declare [[simproc del: neq]]''.
  2218 
  2219 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2220 True/False.
  2221 
  2222 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2223 
  2224 * Theorem setsum_mult renamed to setsum_right_distrib.
  2225 
  2226 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2227 ``rule'' method.
  2228 
  2229 * Reimplemented methods "sat" and "satx", with several improvements:
  2230 goals no longer need to be stated as "<prems> ==> False", equivalences
  2231 (i.e. "=" on type bool) are handled, variable names of the form
  2232 "lit_<n>" are no longer reserved, significant speedup.
  2233 
  2234 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2235 zChaff is still supported as well.
  2236 
  2237 * 'inductive' and 'datatype': provide projections of mutual rules,
  2238 bundled as foo_bar.inducts;
  2239 
  2240 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2241 Library.
  2242 
  2243 * Library: moved theory Accessible_Part to main HOL.
  2244 
  2245 * Library: added theory Coinductive_List of potentially infinite lists
  2246 as greatest fixed-point.
  2247 
  2248 * Library: added theory AssocList which implements (finite) maps as
  2249 association lists.
  2250 
  2251 * Method "evaluation" solves goals (i.e. a boolean expression)
  2252 efficiently by compiling it to ML.  The goal is "proved" (via an
  2253 oracle) if it evaluates to True.
  2254 
  2255 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2256 also when invoked by the simplifier.  This results in the Simplifier
  2257 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2258 Configuration option fast_arith_split_limit=0 recovers the old
  2259 behavior.
  2260 
  2261 * Support for hex (0x20) and binary (0b1001) numerals.
  2262 
  2263 * New method: reify eqs (t), where eqs are equations for an
  2264 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2265 parameter, computes a term s::'b and a list xs::'a list and proves the
  2266 theorem I xs s = t. This is also known as reification or quoting. The
  2267 resulting theorem is applied to the subgoal to substitute t with I xs
  2268 s.  If t is omitted, the subgoal itself is reified.
  2269 
  2270 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2271 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2272 where f is supposed to be a computable function (in the sense of code
  2273 generattion). The method uses reify to compute s and xs as above then
  2274 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2275 r and finally gets the theorem t = r, which is again applied to the
  2276 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2277 
  2278 * Reflection: Automatic reification now handels binding, an example is
  2279 available in src/HOL/ex/ReflectionEx.thy
  2280 
  2281 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2282 command 'statespace' that is similar to 'record', but introduces an
  2283 abstract specification based on the locale infrastructure instead of
  2284 HOL types.  This leads to extra flexibility in composing state spaces,
  2285 in particular multiple inheritance and renaming of components.
  2286 
  2287 
  2288 *** HOL-Complex ***
  2289 
  2290 * Hyperreal: Functions root and sqrt are now defined on negative real
  2291 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2292 Nonnegativity side conditions have been removed from many lemmas, so
  2293 that more subgoals may now be solved by simplification; potential
  2294 INCOMPATIBILITY.
  2295 
  2296 * Real: new type classes formalize real normed vector spaces and
  2297 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2298 and norm :: 'a => real.
  2299 
  2300 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2301 reals into other types. The overloaded constant Reals :: 'a set is now
  2302 defined as range of_real; potential INCOMPATIBILITY.
  2303 
  2304 * Real: proper support for ML code generation, including 'quickcheck'.
  2305 Reals are implemented as arbitrary precision rationals.
  2306 
  2307 * Hyperreal: Several constants that previously worked only for the
  2308 reals have been generalized, so they now work over arbitrary vector
  2309 spaces. Type annotations may need to be added in some cases; potential
  2310 INCOMPATIBILITY.
  2311 
  2312   Infinitesimal  :: ('a::real_normed_vector) star set
  2313   HFinite        :: ('a::real_normed_vector) star set
  2314   HInfinite      :: ('a::real_normed_vector) star set
  2315   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2316   monad          :: ('a::real_normed_vector) star => 'a star set
  2317   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2318   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2319   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2320   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2321   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2322   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2323   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2324   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2325   sgn            :: 'a::real_normed_vector => 'a
  2326   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2327 
  2328 * Complex: Some complex-specific constants are now abbreviations for
  2329 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2330 hnorm.  Other constants have been entirely removed in favor of the
  2331 polymorphic versions (INCOMPATIBILITY):
  2332 
  2333   approx        <-- capprox
  2334   HFinite       <-- CFinite
  2335   HInfinite     <-- CInfinite
  2336   Infinitesimal <-- CInfinitesimal
  2337   monad         <-- cmonad
  2338   galaxy        <-- cgalaxy
  2339   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2340   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2341   (ns)deriv     <-- (ns)cderiv
  2342 
  2343 
  2344 *** HOL-Algebra ***
  2345 
  2346 * Formalisation of ideals and the quotient construction over rings.
  2347 
  2348 * Order and lattice theory no longer based on records.
  2349 INCOMPATIBILITY.
  2350 
  2351 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2352 greatest_closed.  INCOMPATIBILITY.
  2353 
  2354 * Method algebra is now set up via an attribute.  For examples see
  2355 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2356 of algebraic structures.
  2357 
  2358 * Renamed theory CRing to Ring.
  2359 
  2360 
  2361 *** HOL-Nominal ***
  2362 
  2363 * Substantial, yet incomplete support for nominal datatypes (binding
  2364 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2365 src/HOL/Nominal/Examples.  Prospective users should consult
  2366 http://isabelle.in.tum.de/nominal/
  2367 
  2368 
  2369 *** ML ***
  2370 
  2371 * ML basics: just one true type int, which coincides with IntInf.int
  2372 (even on SML/NJ).
  2373 
  2374 * ML within Isar: antiquotations allow to embed statically-checked
  2375 formal entities in the source, referring to the context available at
  2376 compile-time.  For example:
  2377 
  2378 ML {* @{sort "{zero,one}"} *}
  2379 ML {* @{typ "'a => 'b"} *}
  2380 ML {* @{term "%x. x"} *}
  2381 ML {* @{prop "x == y"} *}
  2382 ML {* @{ctyp "'a => 'b"} *}
  2383 ML {* @{cterm "%x. x"} *}
  2384 ML {* @{cprop "x == y"} *}
  2385 ML {* @{thm asm_rl} *}
  2386 ML {* @{thms asm_rl} *}
  2387 ML {* @{type_name c} *}
  2388 ML {* @{type_syntax c} *}
  2389 ML {* @{const_name c} *}
  2390 ML {* @{const_syntax c} *}
  2391 ML {* @{context} *}
  2392 ML {* @{theory} *}
  2393 ML {* @{theory Pure} *}
  2394 ML {* @{theory_ref} *}
  2395 ML {* @{theory_ref Pure} *}
  2396 ML {* @{simpset} *}
  2397 ML {* @{claset} *}
  2398 ML {* @{clasimpset} *}
  2399 
  2400 The same works for sources being ``used'' within an Isar context.
  2401 
  2402 * ML in Isar: improved error reporting; extra verbosity with
  2403 ML_Context.trace enabled.
  2404 
  2405 * Pure/General/table.ML: the join operations now works via exceptions
  2406 DUP/SAME instead of type option. This is simpler in simple cases, and
  2407 admits slightly more efficient complex applications.
  2408 
  2409 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2410 use Context.generic instead of just theory.
  2411 
  2412 * Pure: datatype Context.generic joins theory/Proof.context and
  2413 provides some facilities for code that works in either kind of
  2414 context, notably GenericDataFun for uniform theory and proof data.
  2415 
  2416 * Pure: simplified internal attribute type, which is now always
  2417 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2418 local (Proof.context) attributes have been discontinued, while
  2419 minimizing code duplication. Thm.rule_attribute and
  2420 Thm.declaration_attribute build canonical attributes; see also structure
  2421 Context for further operations on Context.generic, notably
  2422 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2423 declarations and definitions.
  2424 
  2425 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2426 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2427 init only required for impure data. INCOMPATIBILITY: empty really need
  2428 to be empty (no dependencies on theory content!)
  2429 
  2430 * Pure/kernel: consts certification ignores sort constraints given in
  2431 signature declarations. (This information is not relevant to the
  2432 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2433 potential INCOMPATIBILITY.
  2434 
  2435 * Pure: axiomatic type classes are now purely definitional, with
  2436 explicit proofs of class axioms and super class relations performed
  2437 internally. See Pure/axclass.ML for the main internal interfaces --
  2438 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2439 AxClass.axiomatize_class/classrel/arity supersede
  2440 Sign.add_classes/classrel/arities.
  2441 
  2442 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2443 global/local versions on theory vs. Proof.context have been
  2444 discontinued; Attrib.syntax and Method.syntax have been adapted
  2445 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2446 attributes, methods, etc.
  2447 
  2448 * Pure: several functions of signature "... -> theory -> theory * ..."
  2449 have been reoriented to "... -> theory -> ... * theory" in order to
  2450 allow natural usage in combination with the ||>, ||>>, |-> and
  2451 fold_map combinators.
  2452 
  2453 * Pure: official theorem names (closed derivations) and additional
  2454 comments (tags) are now strictly separate.  Name hints -- which are
  2455 maintained as tags -- may be attached any time without affecting the
  2456 derivation.
  2457 
  2458 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2459 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2460 achieve the old behaviour.
  2461 
  2462 * Pure: the "Goal" constant is now called "prop", supporting a
  2463 slightly more general idea of ``protecting'' meta-level rule
  2464 statements.
  2465 
  2466 * Pure: Logic.(un)varify only works in a global context, which is now
  2467 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2468 Logic.legacy_(un)varify as temporary workaround.
  2469 
  2470 * Pure: structure Name provides scalable operations for generating
  2471 internal variable names, notably Name.variants etc.  This replaces
  2472 some popular functions from term.ML:
  2473 
  2474   Term.variant		->  Name.variant
  2475   Term.variantlist	->  Name.variant_list
  2476   Term.invent_names	->  Name.invent_list
  2477 
  2478 Note that low-level renaming rarely occurs in new code -- operations
  2479 from structure Variable are used instead (see below).
  2480 
  2481 * Pure: structure Variable provides fundamental operations for proper
  2482 treatment of fixed/schematic variables in a context.  For example,
  2483 Variable.import introduces fixes for schematics of given facts and
  2484 Variable.export reverses the effect (up to renaming) -- this replaces
  2485 various freeze_thaw operations.
  2486 
  2487 * Pure: structure Goal provides simple interfaces for
  2488 init/conclude/finish and tactical prove operations (replacing former
  2489 Tactic.prove).  Goal.prove is the canonical way to prove results
  2490 within a given context; Goal.prove_global is a degraded version for
  2491 theory level goals, including a global Drule.standard.  Note that
  2492 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2493 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2494 in a locale context).
  2495 
  2496 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2497 and type checking (Syntax.check_term etc.), with common combinations
  2498 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2499 which are considered legacy and await removal.
  2500 
  2501 * Pure/Syntax: generic interfaces for type unchecking
  2502 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2503 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2504 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2505 available for convenience, but refer to the very same operations using
  2506 a mere theory instead of a full context.
  2507 
  2508 * Isar: simplified treatment of user-level errors, using exception
  2509 ERROR of string uniformly.  Function error now merely raises ERROR,
  2510 without any side effect on output channels.  The Isar toplevel takes
  2511 care of proper display of ERROR exceptions.  ML code may use plain
  2512 handle/can/try; cat_error may be used to concatenate errors like this:
  2513 
  2514   ... handle ERROR msg => cat_error msg "..."
  2515 
  2516 Toplevel ML code (run directly or through the Isar toplevel) may be
  2517 embedded into the Isar toplevel with exception display/debug like
  2518 this:
  2519 
  2520   Isar.toplevel (fn () => ...)
  2521 
  2522 INCOMPATIBILITY, removed special transform_error facilities, removed
  2523 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2524 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2525 -- use plain ERROR instead.
  2526 
  2527 * Isar: theory setup now has type (theory -> theory), instead of a
  2528 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2529 
  2530 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2531 ProofContext.debug/verbose flags.
  2532 
  2533 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2534 theory before entering a proof state.  Transactions now always see a
  2535 quasi-functional intermediate checkpoint, both in interactive and
  2536 batch mode.
  2537 
  2538 * Isar: simplified interfaces for outer syntax.  Renamed
  2539 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2540 OuterSyntax.add_parsers -- this functionality is now included in
  2541 OuterSyntax.command etc.  INCOMPATIBILITY.
  2542 
  2543 * Simplifier: the simpset of a running simplification process now
  2544 contains a proof context (cf. Simplifier.the_context), which is the
  2545 very context that the initial simpset has been retrieved from (by
  2546 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2547 (solver, looper etc.) may depend on arbitrary proof data.
  2548 
  2549 * Simplifier.inherit_context inherits the proof context (plus the
  2550 local bounds) of the current simplification process; any simproc
  2551 etc. that calls the Simplifier recursively should do this!  Removed
  2552 former Simplifier.inherit_bounds, which is already included here --
  2553 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2554 specify an explicit context using Simplifier.context/theory_context.
  2555 
  2556 * Simplifier/Classical Reasoner: more abstract interfaces
  2557 change_simpset/claset for modifying the simpset/claset reference of a
  2558 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2559 INCOMPATIBILITY.
  2560 
  2561 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2562 "Trueprop" etc.
  2563 
  2564 
  2565 *** System ***
  2566 
  2567 * settings: the default heap location within ISABELLE_HOME_USER now
  2568 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2569 Isabelle installations.
  2570 
  2571 * isabelle-process: option -S (secure mode) disables some critical
  2572 operations, notably runtime compilation and evaluation of ML source
  2573 code.
  2574 
  2575 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2576 
  2577 * Support for parallel execution, using native multicore support of
  2578 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2579 independent theories, according to the given theory header
  2580 specifications. The maximum number of worker threads is specified via
  2581 usedir option -M or the "max-threads" setting in Proof General. A
  2582 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2583 to 6 on a 8-core machine.  User-code needs to observe certain
  2584 guidelines for thread-safe programming, see appendix A in the Isar
  2585 Implementation manual.
  2586 
  2587 
  2588 
  2589 New in Isabelle2005 (October 2005)
  2590 ----------------------------------
  2591 
  2592 *** General ***
  2593 
  2594 * Theory headers: the new header syntax for Isar theories is
  2595 
  2596   theory <name>
  2597   imports <theory1> ... <theoryN>
  2598   uses <file1> ... <fileM>
  2599   begin
  2600 
  2601 where the 'uses' part is optional.  The previous syntax
  2602 
  2603   theory <name> = <theory1> + ... + <theoryN>:
  2604 
  2605 will disappear in the next release.  Use isatool fixheaders to convert
  2606 existing theory files.  Note that there is no change in ancient
  2607 non-Isar theories now, but these will disappear soon.
  2608 
  2609 * Theory loader: parent theories can now also be referred to via
  2610 relative and absolute paths.
  2611 
  2612 * Command 'find_theorems' searches for a list of criteria instead of a
  2613 list of constants. Known criteria are: intro, elim, dest, name:string,
  2614 simp:term, and any term. Criteria can be preceded by '-' to select
  2615 theorems that do not match. Intro, elim, dest select theorems that
  2616 match the current goal, name:s selects theorems whose fully qualified
  2617 name contain s, and simp:term selects all simplification rules whose
  2618 lhs match term.  Any other term is interpreted as pattern and selects
  2619 all theorems matching the pattern. Available in ProofGeneral under
  2620 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2621 
  2622   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2623 
  2624 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2625 matching the current goal as introduction rule and not having "HOL."
  2626 in their name (i.e. not being defined in theory HOL).
  2627 
  2628 * Command 'thms_containing' has been discontinued in favour of
  2629 'find_theorems'; INCOMPATIBILITY.
  2630 
  2631 * Communication with Proof General is now 8bit clean, which means that
  2632 Unicode text in UTF-8 encoding may be used within theory texts (both
  2633 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2634 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2635 
  2636   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2637   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2638 
  2639 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2640 Classical Reasoner.  Typical big applications run around 2 times
  2641 faster.
  2642 
  2643 
  2644 *** Document preparation ***
  2645 
  2646 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2647 of raw sources.  Only those symbols that do not require additional
  2648 LaTeX packages (depending on comments in isabellesym.sty) are
  2649 displayed properly, everything else is left verbatim.  isatool display
  2650 and isatool print are used as front ends (these are subject to the
  2651 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2652 
  2653 * Command tags control specific markup of certain regions of text,
  2654 notably folding and hiding.  Predefined tags include "theory" (for
  2655 theory begin and end), "proof" for proof commands, and "ML" for
  2656 commands involving ML code; the additional tags "visible" and
  2657 "invisible" are unused by default.  Users may give explicit tag
  2658 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2659 interpretation of tags is determined by the LaTeX job during document
  2660 preparation: see option -V of isatool usedir, or options -n and -t of
  2661 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2662 \isadroptag.
  2663 
  2664 Several document versions may be produced at the same time via isatool
  2665 usedir (the generated index.html will link all of them).  Typical
  2666 specifications include ''-V document=theory,proof,ML'' to present
  2667 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2668 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2669 these parts without any formal replacement text.  The Isabelle site
  2670 default settings produce ''document'' and ''outline'' versions as
  2671 specified above.
  2672 
  2673 * Several new antiquotations:
  2674 
  2675   @{term_type term} prints a term with its type annotated;
  2676 
  2677   @{typeof term} prints the type of a term;
  2678 
  2679   @{const const} is the same as @{term const}, but checks that the
  2680   argument is a known logical constant;
  2681 
  2682   @{term_style style term} and @{thm_style style thm} print a term or
  2683   theorem applying a "style" to it
  2684 
  2685   @{ML text}
  2686 
  2687 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2688 definitions, equations, inequations etc., 'concl' printing only the
  2689 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2690 to print the specified premise.  TermStyle.add_style provides an ML
  2691 interface for introducing further styles.  See also the "LaTeX Sugar"
  2692 document practical applications.  The ML antiquotation prints
  2693 type-checked ML expressions verbatim.
  2694 
  2695 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2696 and 'text' support optional locale specification '(in loc)', which
  2697 specifies the default context for interpreting antiquotations.  For
  2698 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2699 
  2700 * Option 'locale=NAME' of antiquotations specifies an alternative
  2701 context interpreting the subsequent argument.  For example: @{thm
  2702 [locale=lattice] inf_assoc}.
  2703 
  2704 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2705 a proof context.
  2706 
  2707 * Proper output of antiquotations for theory commands involving a
  2708 proof context (such as 'locale' or 'theorem (in loc) ...').
  2709 
  2710 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2711 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2712 
  2713 * isatool usedir: new option -C (default true) controls whether option
  2714 -D should include a copy of the original document directory; -C false
  2715 prevents unwanted effects such as copying of administrative CVS data.
  2716 
  2717 
  2718 *** Pure ***
  2719 
  2720 * Considerably improved version of 'constdefs' command.  Now performs
  2721 automatic type-inference of declared constants; additional support for
  2722 local structure declarations (cf. locales and HOL records), see also
  2723 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2724 sequential dependencies of definitions within a single 'constdefs'
  2725 section; moreover, the declared name needs to be an identifier.  If
  2726 all fails, consider to fall back on 'consts' and 'defs' separately.
  2727 
  2728 * Improved indexed syntax and implicit structures.  First of all,
  2729 indexed syntax provides a notational device for subscripted
  2730 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2731 expressions.  Secondly, in a local context with structure
  2732 declarations, number indexes \<^sub>n or the empty index (default
  2733 number 1) refer to a certain fixed variable implicitly; option
  2734 show_structs controls printing of implicit structures.  Typical
  2735 applications of these concepts involve record types and locales.
  2736 
  2737 * New command 'no_syntax' removes grammar declarations (and
  2738 translations) resulting from the given syntax specification, which is
  2739 interpreted in the same manner as for the 'syntax' command.
  2740 
  2741 * 'Advanced' translation functions (parse_translation etc.) may depend
  2742 on the signature of the theory context being presently used for
  2743 parsing/printing, see also isar-ref manual.
  2744 
  2745 * Improved 'oracle' command provides a type-safe interface to turn an
  2746 ML expression of type theory -> T -> term into a primitive rule of
  2747 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2748 is already included here); see also FOL/ex/IffExample.thy;
  2749 INCOMPATIBILITY.
  2750 
  2751 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2752 before); "cI" is no longer bound, use "c.intro" instead.
  2753 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2754 axclasses vs. locales.
  2755 
  2756 * Improved internal renaming of symbolic identifiers -- attach primes
  2757 instead of base 26 numbers.
  2758 
  2759 * New flag show_question_marks controls printing of leading question
  2760 marks in schematic variable names.
  2761 
  2762 * In schematic variable names, *any* symbol following \<^isub> or
  2763 \<^isup> is now treated as part of the base name.  For example, the
  2764 following works without printing of awkward ".0" indexes:
  2765 
  2766   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2767     by simp
  2768 
  2769 * Inner syntax includes (*(*nested*) comments*).
  2770 
  2771 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2772 annotations as "(00...)".
  2773 
  2774 * Clear separation of logical types and nonterminals, where the latter
  2775 may only occur in 'syntax' specifications or type abbreviations.
  2776 Before that distinction was only partially implemented via type class
  2777 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2778 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2779 exotic syntax specifications may require further adaption
  2780 (e.g. Cube/Cube.thy).
  2781 
  2782 * Removed obsolete type class "logic", use the top sort {} instead.
  2783 Note that non-logical types should be declared as 'nonterminals'
  2784 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2785 specifications.
  2786 
  2787 * Attributes 'induct' and 'cases': type or set names may now be
  2788 locally fixed variables as well.
  2789 
  2790 * Simplifier: can now control the depth to which conditional rewriting
  2791 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2792 Limit.
  2793 
  2794 * Simplifier: simplification procedures may now take the current
  2795 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2796 interface), which is very useful for calling the Simplifier
  2797 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2798 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2799 low-level mk_simproc no longer applies Logic.varify internally, to
  2800 allow for use in a context of fixed variables.
  2801 
  2802 * thin_tac now works even if the assumption being deleted contains !!
  2803 or ==>.  More generally, erule now works even if the major premise of
  2804 the elimination rule contains !! or ==>.
  2805 
  2806 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2807 
  2808 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2809 from Pure, which contains all common declarations already.  Both
  2810 theories are defined via plain Isabelle/Isar .thy files.
  2811 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2812 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2813 use isatool fixcpure to adapt your theory and ML sources.
  2814 
  2815 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2816 selections of theorems in named facts via index ranges.
  2817 
  2818 * 'print_theorems': in theory mode, really print the difference
  2819 wrt. the last state (works for interactive theory development only),
  2820 in proof mode print all local facts (cf. 'print_facts');
  2821 
  2822 * 'hide': option '(open)' hides only base names.
  2823 
  2824 * More efficient treatment of intermediate checkpoints in interactive
  2825 theory development.
  2826 
  2827 * Code generator is now invoked via code_module (incremental code
  2828 generation) and code_library (modular code generation, ML structures
  2829 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2830 must be quoted when used as identifiers.
  2831 
  2832 * New 'value' command for reading, evaluating and printing terms using
  2833 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2834 quoted when used as identifier.
  2835 
  2836 
  2837 *** Locales ***
  2838 
  2839 * New commands for the interpretation of locale expressions in
  2840 theories (1), locales (2) and proof contexts (3).  These generate
  2841 proof obligations from the expression specification.  After the
  2842 obligations have been discharged, theorems of the expression are added
  2843 to the theory, target locale or proof context.  The synopsis of the
  2844 commands is a follows:
  2845 
  2846   (1) interpretation expr inst
  2847   (2) interpretation target < expr
  2848   (3) interpret expr inst
  2849 
  2850 Interpretation in theories and proof contexts require a parameter
  2851 instantiation of terms from the current context.  This is applied to
  2852 specifications and theorems of the interpreted expression.
  2853 Interpretation in locales only permits parameter renaming through the
  2854 locale expression.  Interpretation is smart in that interpretations
  2855 that are active already do not occur in proof obligations, neither are
  2856 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2857 inspect active interpretations of a particular locale.  For details,
  2858 see the Isar Reference manual.  Examples can be found in
  2859 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2860 
  2861 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2862 'interpret' instead.
  2863 
  2864 * New context element 'constrains' for adding type constraints to
  2865 parameters.
  2866 
  2867 * Context expressions: renaming of parameters with syntax
  2868 redeclaration.
  2869 
  2870 * Locale declaration: 'includes' disallowed.
  2871 
  2872 * Proper static binding of attribute syntax -- i.e. types / terms /
  2873 facts mentioned as arguments are always those of the locale definition
  2874 context, independently of the context of later invocations.  Moreover,
  2875 locale operations (renaming and type / term instantiation) are applied
  2876 to attribute arguments as expected.
  2877 
  2878 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2879 actual attributes; rare situations may require Attrib.attribute to
  2880 embed those attributes into Attrib.src that lack concrete syntax.
  2881 Attribute implementations need to cooperate properly with the static
  2882 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2883 Attrib.XXX_thm etc. already do the right thing without further
  2884 intervention.  Only unusual applications -- such as "where" or "of"
  2885 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2886 on the context and the facts involved -- may have to assign parsed
  2887 values to argument tokens explicitly.
  2888 
  2889 * Changed parameter management in theorem generation for long goal
  2890 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2891 theorem statement in rare situations.
  2892 
  2893 * Locale inspection command 'print_locale' omits notes elements.  Use
  2894 'print_locale!' to have them included in the output.
  2895 
  2896 
  2897 *** Provers ***
  2898 
  2899 * Provers/hypsubst.ML: improved version of the subst method, for
  2900 single-step rewriting: it now works in bound variable contexts. New is
  2901 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2902 rewrite a different subterm than the original subst method, which is
  2903 still available as 'simplesubst'.
  2904 
  2905 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2906 and quasi orders.
  2907 
  2908 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2909 reflexive-transitive closure of relations.
  2910 
  2911 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2912 limit (previously hard-coded with a value of 20) user-definable.
  2913 
  2914 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2915 is peformed already.  Object-logics merely need to finish their
  2916 initial simpset configuration as before.  INCOMPATIBILITY.
  2917 
  2918 
  2919 *** HOL ***
  2920 
  2921 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2922 
  2923   syntax (epsilon)
  2924     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2925 
  2926 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2927 and x-symbol; use option '-m epsilon' to get it actually printed.
  2928 Moreover, the mathematically important symbolic identifier \<epsilon>
  2929 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2930 
  2931 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2932 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2933 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2934 support corresponding Isar calculations.
  2935 
  2936 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2937 instead of ":".
  2938 
  2939 * theory SetInterval: changed the syntax for open intervals:
  2940 
  2941   Old       New
  2942   {..n(}    {..<n}
  2943   {)n..}    {n<..}
  2944   {m..n(}   {m..<n}
  2945   {)m..n}   {m<..n}
  2946   {)m..n(}  {m<..<n}
  2947 
  2948 The old syntax is still supported but will disappear in the next
  2949 release.  For conversion use the following Emacs search and replace
  2950 patterns (these are not perfect but work quite well):
  2951 
  2952   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2953   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2954 
  2955 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2956 equalities in commutative rings; method 'algebra' provides a generic
  2957 interface.
  2958 
  2959 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2960 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2961 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2962 be a tuple pattern.
  2963 
  2964 Some new syntax forms are available:
  2965 
  2966   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2967   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2968   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2969   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2970 
  2971 The latter form "\<Sum>x < k. e" used to be based on a separate
  2972 function "Summation", which has been discontinued.
  2973 
  2974 * theory Finite_Set: in structured induction proofs, the insert case
  2975 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2976 (insert F x)'.
  2977 
  2978 * The 'refute' command has been extended to support a much larger
  2979 fragment of HOL, including axiomatic type classes, constdefs and
  2980 typedefs, inductive datatypes and recursion.
  2981 
  2982 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2983 Requires zChaff with proof generation to be installed.  See
  2984 HOL/ex/SAT_Examples.thy for examples.
  2985 
  2986 * Datatype induction via method 'induct' now preserves the name of the
  2987 induction variable. For example, when proving P(xs::'a list) by
  2988 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2989 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2990 in unstructured proof scripts.
  2991 
  2992 * Reworked implementation of records.  Improved scalability for
  2993 records with many fields, avoiding performance problems for type
  2994 inference. Records are no longer composed of nested field types, but
  2995 of nested extension types. Therefore the record type only grows linear
  2996 in the number of extensions and not in the number of fields.  The
  2997 top-level (users) view on records is preserved.  Potential
  2998 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2999 old record representation. The type generated for a record is called
  3000 <record_name>_ext_type.
  3001 
  3002 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3003 proofs triggered by a record definition or a simproc (if
  3004 quick_and_dirty is enabled).  Definitions of large records can take
  3005 quite long.
  3006 
  3007 New simproc record_upd_simproc for simplification of multiple record
  3008 updates enabled by default.  Moreover, trivial updates are also
  3009 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3010 occasionally, since simplification is more powerful by default.
  3011 
  3012 * typedef: proper support for polymorphic sets, which contain extra
  3013 type-variables in the term.
  3014 
  3015 * Simplifier: automatically reasons about transitivity chains
  3016 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3017 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3018 old proofs break occasionally as simplification may now solve more
  3019 goals than previously.
  3020 
  3021 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3022 present.  Works for all partial orders (class "order"), in particular
  3023 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3024 just like y <= x.
  3025 
  3026 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3027 bound variable or a constant then the let is unfolded.  Otherwise
  3028 first a is simplified to b, and then f b is simplified to g. If
  3029 possible we abstract b from g arriving at "let x = b in h x",
  3030 otherwise we unfold the let and arrive at g.  The simproc can be
  3031 enabled/disabled by the reference use_let_simproc.  Potential
  3032 INCOMPATIBILITY since simplification is more powerful by default.
  3033 
  3034 * Classical reasoning: the meson method now accepts theorems as arguments.
  3035 
  3036 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3037 jobs to provide advice on the provability of subgoals.
  3038 
  3039 * Theory OrderedGroup and Ring_and_Field: various additions and
  3040 improvements to faciliate calculations involving equalities and
  3041 inequalities.
  3042 
  3043 The following theorems have been eliminated or modified
  3044 (INCOMPATIBILITY):
  3045 
  3046   abs_eq             now named abs_of_nonneg
  3047   abs_of_ge_0        now named abs_of_nonneg
  3048   abs_minus_eq       now named abs_of_nonpos
  3049   imp_abs_id         now named abs_of_nonneg
  3050   imp_abs_neg_id     now named abs_of_nonpos
  3051   mult_pos           now named mult_pos_pos
  3052   mult_pos_le        now named mult_nonneg_nonneg
  3053   mult_pos_neg_le    now named mult_nonneg_nonpos
  3054   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3055   mult_neg           now named mult_neg_neg
  3056   mult_neg_le        now named mult_nonpos_nonpos
  3057 
  3058 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3059      
  3060      zero_le_square
  3061      not_square_less_zero 
  3062 
  3063   The following lemmas have been deleted from Real/RealPow:
  3064   
  3065      realpow_zero_zero
  3066      realpow_two
  3067      realpow_less
  3068      zero_le_power
  3069      realpow_two_le
  3070      abs_realpow_two
  3071      realpow_two_abs     
  3072 
  3073 * Theory Parity: added rules for simplifying exponents.
  3074 
  3075 * Theory List:
  3076 
  3077 The following theorems have been eliminated or modified
  3078 (INCOMPATIBILITY):
  3079 
  3080   list_all_Nil       now named list_all.simps(1)
  3081   list_all_Cons      now named list_all.simps(2)
  3082   list_all_conv      now named list_all_iff
  3083   set_mem_eq         now named mem_iff
  3084 
  3085 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3086 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3087 
  3088 
  3089 *** HOL-Complex ***
  3090 
  3091 * Theory RealDef: better support for embedding natural numbers and
  3092 integers in the reals.
  3093 
  3094 The following theorems have been eliminated or modified
  3095 (INCOMPATIBILITY):
  3096 
  3097   exp_ge_add_one_self  now requires no hypotheses
  3098   real_of_int_add      reversed direction of equality (use [symmetric])
  3099   real_of_int_minus    reversed direction of equality (use [symmetric])
  3100   real_of_int_diff     reversed direction of equality (use [symmetric])
  3101   real_of_int_mult     reversed direction of equality (use [symmetric])
  3102 
  3103 * Theory RComplete: expanded support for floor and ceiling functions.
  3104 
  3105 * Theory Ln is new, with properties of the natural logarithm
  3106 
  3107 * Hyperreal: There is a new type constructor "star" for making
  3108 nonstandard types.  The old type names are now type synonyms:
  3109 
  3110   hypreal = real star
  3111   hypnat = nat star
  3112   hcomplex = complex star
  3113 
  3114 * Hyperreal: Many groups of similarly-defined constants have been
  3115 replaced by polymorphic versions (INCOMPATIBILITY):
  3116 
  3117   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3118 
  3119   starset      <-- starsetNat, starsetC
  3120   *s*          <-- *sNat*, *sc*
  3121   starset_n    <-- starsetNat_n, starsetC_n
  3122   *sn*         <-- *sNatn*, *scn*
  3123   InternalSets <-- InternalNatSets, InternalCSets
  3124 
  3125   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3126   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3127   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3128   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3129   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3130 
  3131 * Hyperreal: Many type-specific theorems have been removed in favor of
  3132 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3133 
  3134   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3135   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3136   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3137   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3138   right_minus <-- hypreal_add_minus
  3139   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3140   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3141   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3142   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3143   mult_1_right <-- hcomplex_mult_one_right
  3144   mult_zero_left <-- hcomplex_mult_zero_left
  3145   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3146   right_distrib <-- hypnat_add_mult_distrib2
  3147   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3148   right_inverse <-- hypreal_mult_inverse
  3149   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3150   order_refl <-- {hypreal,hypnat}_le_refl
  3151   order_trans <-- {hypreal,hypnat}_le_trans
  3152   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3153   order_less_le <-- {hypreal,hypnat}_less_le
  3154   linorder_linear <-- {hypreal,hypnat}_le_linear
  3155   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3156   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3157   add_nonneg_nonneg <-- hypreal_le_add_order
  3158 
  3159 * Hyperreal: Separate theorems having to do with type-specific
  3160 versions of constants have been merged into theorems that apply to the
  3161 new polymorphic constants (INCOMPATIBILITY):
  3162 
  3163   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3164   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3165   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3166   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3167   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3168   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3169   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3170   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3171   STAR_diff <-- {STAR,STARC}_diff
  3172   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3173     STARC_hcomplex_of_complex}_image_subset
  3174   starset_n_Un <-- starset{Nat,C}_n_Un
  3175   starset_n_Int <-- starset{Nat,C}_n_Int
  3176   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3177   starset_n_diff <-- starset{Nat,C}_n_diff
  3178   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3179   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3180   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3181   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3182   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3183   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3184   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3185   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3186   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3187   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3188   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3189   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3190   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3191   starfun_diff <-- starfun{C,RC,CR}_diff
  3192   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3193   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3194   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3195   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3196   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3197   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3198   starfun_Id <-- starfunC_Id
  3199   starfun_approx <-- starfun{Nat,CR}_approx
  3200   starfun_capprox <-- starfun{C,RC}_capprox
  3201   starfun_abs <-- starfunNat_rabs
  3202   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3203   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3204   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3205   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3206   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3207   starfun_add_approx <-- starfunCR_add_approx
  3208   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3209   starfun_divide <-- starfun{C,CR,RC}_divide
  3210   starfun_n <-- starfun{Nat,C}_n
  3211   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3212   starfun_n_add <-- starfun{Nat,C}_n_add
  3213   starfun_n_add_minus <-- starfunNat_n_add_minus
  3214   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3215   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3216   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3217 
  3218   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3219   star_n_minus <-- {hypreal,hcomplex}_minus
  3220   star_n_diff <-- {hypreal,hcomplex}_diff
  3221   star_n_mult <-- {hypreal,hcomplex}_mult
  3222   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3223   star_n_le <-- {hypreal,hypnat}_le
  3224   star_n_less <-- {hypreal,hypnat}_less
  3225   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3226   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3227   star_n_abs <-- hypreal_hrabs
  3228   star_n_divide <-- hcomplex_divide
  3229 
  3230   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3231   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3232   star_of_diff <-- hypreal_of_real_diff
  3233   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3234   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3235   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3236   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3237   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3238   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3239   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3240   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3241   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3242   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3243   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3244   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3245   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3246   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3247   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3248   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3249   star_of_power <-- hypreal_of_real_power
  3250   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3251 
  3252 * Hyperreal: new method "transfer" that implements the transfer
  3253 principle of nonstandard analysis. With a subgoal that mentions
  3254 nonstandard types like "'a star", the command "apply transfer"
  3255 replaces it with an equivalent one that mentions only standard types.
  3256 To be successful, all free variables must have standard types; non-
  3257 standard variables must have explicit universal quantifiers.
  3258 
  3259 * Hyperreal: A theory of Taylor series.
  3260 
  3261 
  3262 *** HOLCF ***
  3263 
  3264 * Discontinued special version of 'constdefs' (which used to support
  3265 continuous functions) in favor of the general Pure one with full
  3266 type-inference.
  3267 
  3268 * New simplification procedure for solving continuity conditions; it
  3269 is much faster on terms with many nested lambda abstractions (cubic
  3270 instead of exponential time).
  3271 
  3272 * New syntax for domain package: selector names are now optional.
  3273 Parentheses should be omitted unless argument is lazy, for example:
  3274 
  3275   domain 'a stream = cons "'a" (lazy "'a stream")
  3276 
  3277 * New command 'fixrec' for defining recursive functions with pattern
  3278 matching; defining multiple functions with mutual recursion is also
  3279 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3280 sinr, or any data constructor defined by the domain package. The given
  3281 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3282 syntax and examples.
  3283 
  3284 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3285 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3286 but the proof obligation additionally includes an admissibility
  3287 requirement. The packages generate instances of class cpo or pcpo,
  3288 with continuity and strictness theorems for Rep and Abs.
  3289 
  3290 * HOLCF: Many theorems have been renamed according to a more standard naming
  3291 scheme (INCOMPATIBILITY):
  3292 
  3293   foo_inject:  "foo$x = foo$y ==> x = y"
  3294   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3295   foo_less:    "(foo$x << foo$y) = (x << y)"
  3296   foo_strict:  "foo$UU = UU"
  3297   foo_defined: "... ==> foo$x ~= UU"
  3298   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3299 
  3300 
  3301 *** ZF ***
  3302 
  3303 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3304 including the First Isomorphism Theorem (on quotienting by the kernel
  3305 of a homomorphism).
  3306 
  3307 * ZF/Simplifier: install second copy of type solver that actually
  3308 makes use of TC rules declared to Isar proof contexts (or locales);
  3309 the old version is still required for ML proof scripts.
  3310 
  3311 
  3312 *** Cube ***
  3313 
  3314 * Converted to Isar theory format; use locales instead of axiomatic
  3315 theories.
  3316 
  3317 
  3318 *** ML ***
  3319 
  3320 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3321 for ||>, ||>>, |>>,
  3322 
  3323 * Pure/library.ML no longer defines its own option datatype, but uses
  3324 that of the SML basis, which has constructors NONE and SOME instead of
  3325 None and Some, as well as exception Option.Option instead of OPTION.
  3326 The functions the, if_none, is_some, is_none have been adapted
  3327 accordingly, while Option.map replaces apsome.
  3328 
  3329 * Pure/library.ML: the exception LIST has been given up in favour of
  3330 the standard exceptions Empty and Subscript, as well as
  3331 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3332 superceded by the standard hd and tl functions etc.
  3333 
  3334 A number of basic list functions are no longer exported to the ML
  3335 toplevel, as they are variants of predefined functions.  The following
  3336 suggests how one can translate existing code:
  3337 
  3338     rev_append xs ys = List.revAppend (xs, ys)
  3339     nth_elem (i, xs) = List.nth (xs, i)
  3340     last_elem xs = List.last xs
  3341     flat xss = List.concat xss
  3342     seq fs = List.app fs
  3343     partition P xs = List.partition P xs
  3344     mapfilter f xs = List.mapPartial f xs
  3345 
  3346 * Pure/library.ML: several combinators for linear functional
  3347 transformations, notably reverse application and composition:
  3348 
  3349   x |> f                f #> g
  3350   (x, y) |-> f          f #-> g
  3351 
  3352 * Pure/library.ML: introduced/changed precedence of infix operators:
  3353 
  3354   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3355   infix 2 ?;
  3356   infix 3 o oo ooo oooo;
  3357   infix 4 ~~ upto downto;
  3358 
  3359 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3360 infix operators.
  3361 
  3362 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3363 fold_map support linear functional transformations and nesting.  For
  3364 example:
  3365 
  3366   fold f [x1, ..., xN] y =
  3367     y |> f x1 |> ... |> f xN
  3368 
  3369   (fold o fold) f [xs1, ..., xsN] y =
  3370     y |> fold f xs1 |> ... |> fold f xsN
  3371 
  3372   fold f [x1, ..., xN] =
  3373     f x1 #> ... #> f xN
  3374 
  3375   (fold o fold) f [xs1, ..., xsN] =
  3376     fold f xs1 #> ... #> fold f xsN
  3377 
  3378 * Pure/library.ML: the following selectors on type 'a option are
  3379 available:
  3380 
  3381   the:               'a option -> 'a  (*partial*)
  3382   these:             'a option -> 'a  where 'a = 'b list
  3383   the_default: 'a -> 'a option -> 'a
  3384   the_list:          'a option -> 'a list
  3385 
  3386 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3387 basic operations for association lists, following natural argument
  3388 order; moreover the explicit equality predicate passed here avoids
  3389 potentially expensive polymorphic runtime equality checks.
  3390 The old functions may be expressed as follows:
  3391 
  3392   assoc = uncurry (AList.lookup (op =))
  3393   assocs = these oo AList.lookup (op =)
  3394   overwrite = uncurry (AList.update (op =)) o swap
  3395 
  3396 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3397 
  3398   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3399   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3400 
  3401 replacing make_keylist and keyfilter (occassionally used)
  3402 Naive rewrites:
  3403 
  3404   make_keylist = AList.make
  3405   keyfilter = AList.find (op =)
  3406 
  3407 * eq_fst and eq_snd now take explicit equality parameter, thus
  3408   avoiding eqtypes. Naive rewrites:
  3409 
  3410     eq_fst = eq_fst (op =)
  3411     eq_snd = eq_snd (op =)
  3412 
  3413 * Removed deprecated apl and apr (rarely used).
  3414   Naive rewrites:
  3415 
  3416     apl (n, op) =>>= curry op n
  3417     apr (op, m) =>>= fn n => op (n, m)
  3418 
  3419 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3420 provides a reasonably efficient light-weight implementation of sets as
  3421 lists.
  3422 
  3423 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3424 few new operations; existing lookup and update are now curried to
  3425 follow natural argument order (for use with fold etc.);
  3426 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3427 
  3428 * Pure/General: output via the Isabelle channels of
  3429 writeln/warning/error etc. is now passed through Output.output, with a
  3430 hook for arbitrary transformations depending on the print_mode
  3431 (cf. Output.add_mode -- the first active mode that provides a output
  3432 function wins).  Already formatted output may be embedded into further
  3433 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3434 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3435 accommodate easy composition of diagnostic messages etc.  Programmers
  3436 rarely need to care about Output.output or Output.raw at all, with
  3437 some notable exceptions: Output.output is required when bypassing the
  3438 standard channels (writeln etc.), or in token translations to produce
  3439 properly formatted results; Output.raw is required when capturing
  3440 already output material that will eventually be presented to the user
  3441 a second time.  For the default print mode, both Output.output and
  3442 Output.raw have no effect.
  3443 
  3444 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3445 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3446 cumulative results are displayed at the end of a batch session.
  3447 
  3448 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3449 replaced by File.platform_path and File.shell_path (with appropriate
  3450 hooks).  This provides a clean interface for unusual systems where the
  3451 internal and external process view of file names are different.
  3452 
  3453 * Pure: more efficient orders for basic syntactic entities: added
  3454 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3455 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3456 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3457 orders now -- potential INCOMPATIBILITY for code that depends on a
  3458 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3459 Library.sort_strings on result).
  3460 
  3461 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3462 fold_types traverse types/terms from left to right, observing natural
  3463 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3464 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3465 
  3466 * Pure: name spaces have been refined, with significant changes of the
  3467 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3468 to extern(_table).  The plain name entry path is superceded by a
  3469 general 'naming' context, which also includes the 'policy' to produce
  3470 a fully qualified name and external accesses of a fully qualified
  3471 name; NameSpace.extend is superceded by context dependent
  3472 Sign.declare_name.  Several theory and proof context operations modify
  3473 the naming context.  Especially note Theory.restore_naming and
  3474 ProofContext.restore_naming to get back to a sane state; note that
  3475 Theory.add_path is no longer sufficient to recover from
  3476 Theory.absolute_path in particular.
  3477 
  3478 * Pure: new flags short_names (default false) and unique_names
  3479 (default true) for controlling output of qualified names.  If
  3480 short_names is set, names are printed unqualified.  If unique_names is
  3481 reset, the name prefix is reduced to the minimum required to achieve
  3482 the original result when interning again, even if there is an overlap
  3483 with earlier declarations.
  3484 
  3485 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3486 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3487 (useful for printing error messages).  INCOMPATIBILITY.
  3488 
  3489 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3490 Theory.theory are now identified, referring to the universal
  3491 Context.theory (see Pure/context.ML).  Actual signature and theory
  3492 content is managed as theory data.  The old code and interfaces were
  3493 spread over many files and structures; the new arrangement introduces
  3494 considerable INCOMPATIBILITY to gain more clarity:
  3495 
  3496   Context -- theory management operations (name, identity, inclusion,
  3497     parents, ancestors, merge, etc.), plus generic theory data;
  3498 
  3499   Sign -- logical signature and syntax operations (declaring consts,
  3500     types, etc.), plus certify/read for common entities;
  3501 
  3502   Theory -- logical theory operations (stating axioms, definitions,
  3503     oracles), plus a copy of logical signature operations (consts,
  3504     types, etc.); also a few basic management operations (Theory.copy,
  3505     Theory.merge, etc.)
  3506 
  3507 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3508 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3509 for convenience -- they merely return the theory.
  3510 
  3511 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3512 
  3513 * Pure: the Isar proof context type is already defined early in Pure
  3514 as Context.proof (note that ProofContext.context and Proof.context are
  3515 aliases, where the latter is the preferred name).  This enables other
  3516 Isabelle components to refer to that type even before Isar is present.
  3517 
  3518 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3519 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3520 any of these kinds.  For example, Sign.intern typeK is now
  3521 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3522 Theory.hide_types.  Also note that former
  3523 Theory.hide_classes/types/consts are now
  3524 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3525 internalize their arguments!  INCOMPATIBILITY.
  3526 
  3527 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3528 datatype thmref (with constructors Name and NameSelection) instead of
  3529 plain string -- INCOMPATIBILITY;
  3530 
  3531 * Pure: cases produced by proof methods specify options, where NONE
  3532 means to remove case bindings -- INCOMPATIBILITY in
  3533 (RAW_)METHOD_CASES.
  3534 
  3535 * Pure: the following operations retrieve axioms or theorems from a
  3536 theory node or theory hierarchy, respectively:
  3537 
  3538   Theory.axioms_of: theory -> (string * term) list
  3539   Theory.all_axioms_of: theory -> (string * term) list
  3540   PureThy.thms_of: theory -> (string * thm) list
  3541   PureThy.all_thms_of: theory -> (string * thm) list
  3542 
  3543 * Pure: print_tac now outputs the goal through the trace channel.
  3544 
  3545 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3546 Reference Toplevel.debug (default false) controls detailed printing
  3547 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3548 controls execution profiling -- set to 1 for time and 2 for space
  3549 (both increase the runtime).
  3550 
  3551 * Isar session: The initial use of ROOT.ML is now always timed,
  3552 i.e. the log will show the actual process times, in contrast to the
  3553 elapsed wall-clock time that the outer shell wrapper produces.
  3554 
  3555 * Simplifier: improved handling of bound variables (nameless
  3556 representation, avoid allocating new strings).  Simprocs that invoke
  3557 the Simplifier recursively should use Simplifier.inherit_bounds to
  3558 avoid local name clashes.  Failure to do so produces warnings
  3559 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3560 for further details.
  3561 
  3562 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3563 bindings for all theorems stored within a given theory; this may help
  3564 in porting non-Isar theories to Isar ones, while keeping ML proof
  3565 scripts for the time being.
  3566 
  3567 * ML operator HTML.with_charset specifies the charset begin used for
  3568 generated HTML files.  For example:
  3569 
  3570   HTML.with_charset "utf-8" use_thy "Hebrew";
  3571   HTML.with_charset "utf-8" use_thy "Chinese";
  3572 
  3573 
  3574 *** System ***
  3575 
  3576 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3577 isabelle, isatool etc.).
  3578 
  3579 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3580 isatool doc, isatool mkdir, display_drafts etc.).
  3581 
  3582 * isatool usedir: option -f allows specification of the ML file to be
  3583 used by Isabelle; default is ROOT.ML.
  3584 
  3585 * New isatool version outputs the version identifier of the Isabelle
  3586 distribution being used.
  3587 
  3588 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3589 (containing Boolean satisfiability problems) into Isabelle/HOL
  3590 theories.
  3591 
  3592 
  3593 
  3594 New in Isabelle2004 (April 2004)
  3595 --------------------------------
  3596 
  3597 *** General ***
  3598 
  3599 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3600   Replaces linorder.ML.
  3601 
  3602 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3603   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3604   (\<a>...\<z>), are now considered normal letters, and can therefore
  3605   be used anywhere where an ASCII letter (a...zA...Z) has until
  3606   now. COMPATIBILITY: This obviously changes the parsing of some
  3607   terms, especially where a symbol has been used as a binder, say
  3608   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3609   as an identifier.  Fix it by inserting a space around former
  3610   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3611   existing theory and ML files.
  3612 
  3613 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3614 
  3615 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3616   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3617   a normal (but invisible) letter. For multiple letter subscripts repeat
  3618   \<^isub> like this: x\<^isub>1\<^isub>2.
  3619 
  3620 * Pure: There are now sub-/superscripts that can span more than one
  3621   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3622   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3623   superscript. The new control characters are not identifier parts.
  3624 
  3625 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3626   content of "..." to the latex file instead of \isacntrl... . The "..."
  3627   may consist of any printable characters excluding the end bracket >.
  3628 
  3629 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3630   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3631   declare constants "final", which prevents their being given a definition
  3632   later.  It is useful for constants whose behaviour is fixed axiomatically
  3633   rather than definitionally, such as the meta-logic connectives.
  3634 
  3635 * Pure: 'instance' now handles general arities with general sorts
  3636   (i.e. intersections of classes),
  3637 
  3638 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3639   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3640   It can be changed to alter the colors/layout of generated pages.
  3641 
  3642 
  3643 *** Isar ***
  3644 
  3645 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3646   cut_tac, subgoal_tac and thin_tac:
  3647   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3648     locales are no longer forced to write Isar proof scripts.
  3649     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3650     emulations.
  3651   - INCOMPATIBILITY: names of variables to be instantiated may no
  3652     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3653     This is consistent with the instantiation attribute "where".
  3654 
  3655 * Attributes "where" and "of":
  3656   - Now take type variables of instantiated theorem into account when reading
  3657     the instantiation string.  This fixes a bug that caused instantiated
  3658     theorems to have too special types in some circumstances.
  3659   - "where" permits explicit instantiations of type variables.
  3660 
  3661 * Calculation commands "moreover" and "also" no longer interfere with
  3662   current facts ("this"), admitting arbitrary combinations with "then"
  3663   and derived forms.
  3664 
  3665 * Locales:
  3666   - Goal statements involving the context element "includes" no longer
  3667     generate theorems with internal delta predicates (those ending on
  3668     "_axioms") in the premise.
  3669     Resolve particular premise with <locale>.intro to obtain old form.
  3670   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3671     specification and "includes" elements in goal statement.
  3672   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3673     [intro?] and [elim?] (respectively) by default.
  3674   - Experimental command for instantiation of locales in proof contexts:
  3675         instantiate <label>[<attrs>]: <loc>
  3676     Instantiates locale <loc> and adds all its theorems to the current context
  3677     taking into account their attributes.  Label and attrs are optional
  3678     modifiers, like in theorem declarations.  If present, names of
  3679     instantiated theorems are qualified with <label>, and the attributes
  3680     <attrs> are applied after any attributes these theorems might have already.
  3681       If the locale has assumptions, a chained fact of the form
  3682     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3683     are derived.  The command does not support old-style locales declared
  3684     with "locale (open)".
  3685       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3686 
  3687 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3688   (Isar) contexts.
  3689 
  3690 
  3691 *** HOL ***
  3692 
  3693 * Proof import: new image HOL4 contains the imported library from
  3694   the HOL4 system with about 2500 theorems. It is imported by
  3695   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3696   can be used like any other Isabelle image.  See
  3697   HOL/Import/HOL/README for more information.
  3698 
  3699 * Simplifier:
  3700   - Much improved handling of linear and partial orders.
  3701     Reasoners for linear and partial orders are set up for type classes
  3702     "linorder" and "order" respectively, and are added to the default simpset
  3703     as solvers.  This means that the simplifier can build transitivity chains
  3704     to solve goals from the assumptions.
  3705   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3706     of blast or auto after simplification become unnecessary because the goal
  3707     is solved by simplification already.
  3708 
  3709 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3710     all proved in axiomatic type classes for semirings, rings and fields.
  3711 
  3712 * Numerics:
  3713   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3714     now formalized using the Ring_and_Field theory mentioned above.
  3715   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3716     than before, because now they are set up once in a generic manner.
  3717   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3718     Look for the general versions in Ring_and_Field (and Power if they concern
  3719     exponentiation).
  3720 
  3721 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3722 
  3723 * Records:
  3724   - Record types are now by default printed with their type abbreviation
  3725     instead of the list of all field types. This can be configured via
  3726     the reference "print_record_type_abbr".
  3727   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3728     (not enabled by default).
  3729   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3730     EX x. x = sel r to True (not enabled by default).
  3731   - Tactic "record_split_simp_tac" to split and simplify records added.
  3732 
  3733 * 'specification' command added, allowing for definition by
  3734   specification.  There is also an 'ax_specification' command that
  3735   introduces the new constants axiomatically.
  3736 
  3737 * arith(_tac) is now able to generate counterexamples for reals as well.
  3738 
  3739 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3740 
  3741 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3742   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3743 
  3744 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3745   matrix theory to linear programming.
  3746 
  3747 * Unions and Intersections:
  3748   The latex output syntax of UN and INT has been changed
  3749   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3750   i.e. the index formulae has become a subscript.
  3751   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3752 
  3753 * Unions and Intersections over Intervals:
  3754   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3755   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3756   like in normal math, and corresponding versions for < and for intersection.
  3757 
  3758 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3759   lexicographic dictonary ordering has been added as "lexord".
  3760 
  3761 * ML: the legacy theory structures Int and List have been removed. They had
  3762   conflicted with ML Basis Library structures having the same names.
  3763 
  3764 * 'refute' command added to search for (finite) countermodels.  Only works
  3765   for a fragment of HOL.  The installation of an external SAT solver is
  3766   highly recommended.  See "HOL/Refute.thy" for details.
  3767 
  3768 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3769   formulae under an assignment of free variables to random values.
  3770   In contrast to 'refute', it can deal with inductive datatypes,
  3771   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3772   for examples.
  3773 
  3774 
  3775 *** HOLCF ***
  3776 
  3777 * Streams now come with concatenation and are part of the HOLCF image
  3778 
  3779 
  3780 
  3781 New in Isabelle2003 (May 2003)
  3782 ------------------------------
  3783 
  3784 *** General ***
  3785 
  3786 * Provers/simplifier:
  3787 
  3788   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3789     Assumptions are now subject to complete mutual simplification,
  3790     not just from left to right. The simplifier now preserves
  3791     the order of assumptions.
  3792 
  3793     Potential INCOMPATIBILITY:
  3794 
  3795     -- simp sometimes diverges where the old version did
  3796        not, e.g. invoking simp on the goal
  3797 
  3798         [| P (f x); y = x; f x = f y |] ==> Q
  3799 
  3800        now gives rise to the infinite reduction sequence
  3801 
  3802         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3803 
  3804        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3805        kind of problem.
  3806 
  3807     -- Tactics combining classical reasoner and simplification (such as auto)
  3808        are also affected by this change, because many of them rely on
  3809        simp. They may sometimes diverge as well or yield a different numbers
  3810        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3811        in case of problems. Sometimes subsequent calls to the classical
  3812        reasoner will fail because a preceeding call to the simplifier too
  3813        eagerly simplified the goal, e.g. deleted redundant premises.
  3814 
  3815   - The simplifier trace now shows the names of the applied rewrite rules
  3816 
  3817   - You can limit the number of recursive invocations of the simplifier
  3818     during conditional rewriting (where the simplifie tries to solve the
  3819     conditions before applying the rewrite rule):
  3820     ML "simp_depth_limit := n"
  3821     where n is an integer. Thus you can force termination where previously
  3822     the simplifier would diverge.
  3823 
  3824   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3825 
  3826   - No longer aborts on failed congruence proof.  Instead, the
  3827     congruence is ignored.
  3828 
  3829 * Pure: New generic framework for extracting programs from constructive
  3830   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3831   as HOL/Extraction for some case studies.
  3832 
  3833 * Pure: The main goal of the proof state is no longer shown by default, only
  3834 the subgoals. This behaviour is controlled by a new flag.
  3835    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3836 (ML: Proof.show_main_goal).
  3837 
  3838 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3839 rules whose conclusion matches subgoal 1:
  3840       PG menu: Isabelle/Isar -> Show me -> matching rules
  3841 The rules are ordered by how closely they match the subgoal.
  3842 In particular, rules that solve a subgoal outright are displayed first
  3843 (or rather last, the way they are printed).
  3844 (ML: ProofGeneral.print_intros())
  3845 
  3846 * Pure: New flag trace_unify_fail causes unification to print
  3847 diagnostic information (PG: in trace buffer) when it fails. This is
  3848 useful for figuring out why single step proofs like rule, erule or
  3849 assumption failed.
  3850 
  3851 * Pure: Locale specifications now produce predicate definitions
  3852 according to the body of text (covering assumptions modulo local
  3853 definitions); predicate "loc_axioms" covers newly introduced text,
  3854 while "loc" is cumulative wrt. all included locale expressions; the
  3855 latter view is presented only on export into the global theory
  3856 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3857 on the old view without predicates;
  3858 
  3859 * Pure: predefined locales "var" and "struct" are useful for sharing
  3860 parameters (as in CASL, for example); just specify something like
  3861 ``var x + var y + struct M'' as import;
  3862 
  3863 * Pure: improved thms_containing: proper indexing of facts instead of
  3864 raw theorems; check validity of results wrt. current name space;
  3865 include local facts of proof configuration (also covers active
  3866 locales), cover fixed variables in index; may use "_" in term
  3867 specification; an optional limit for the number of printed facts may
  3868 be given (the default is 40);
  3869 
  3870 * Pure: disallow duplicate fact bindings within new-style theory files
  3871 (batch-mode only);
  3872 
  3873 * Provers: improved induct method: assumptions introduced by case
  3874 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3875 the goal statement); "foo" still refers to all facts collectively;
  3876 
  3877 * Provers: the function blast.overloaded has been removed: all constants
  3878 are regarded as potentially overloaded, which improves robustness in exchange
  3879 for slight decrease in efficiency;
  3880 
  3881 * Provers/linorder: New generic prover for transitivity reasoning over
  3882 linear orders.  Note: this prover is not efficient!
  3883 
  3884 * Isar: preview of problems to finish 'show' now produce an error
  3885 rather than just a warning (in interactive mode);
  3886 
  3887 
  3888 *** HOL ***
  3889 
  3890 * arith(_tac)
  3891 
  3892  - Produces a counter example if it cannot prove a goal.
  3893    Note that the counter example may be spurious if the goal is not a formula
  3894    of quantifier-free linear arithmetic.
  3895    In ProofGeneral the counter example appears in the trace buffer.
  3896 
  3897  - Knows about div k and mod k where k is a numeral of type nat or int.
  3898 
  3899  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3900    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3901    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3902 
  3903 * simp's arithmetic capabilities have been enhanced a bit: it now
  3904 takes ~= in premises into account (by performing a case split);
  3905 
  3906 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3907 are distributed over a sum of terms;
  3908 
  3909 * New tactic "trans_tac" and method "trans" instantiate
  3910 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3911 "<=", "<" and "=").
  3912 
  3913 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3914 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3915 
  3916 * 'typedef' command has new option "open" to suppress the set
  3917 definition;
  3918 
  3919 * functions Min and Max on finite sets have been introduced (theory
  3920 Finite_Set);
  3921 
  3922 * attribute [symmetric] now works for relations as well; it turns
  3923 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3924 
  3925 * induct over a !!-quantified statement (say !!x1..xn):
  3926   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3927 
  3928 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3929 %x. None. Warning: empty_def now refers to the previously hidden definition
  3930 of the empty set.
  3931 
  3932 * Algebra: formalization of classical algebra.  Intended as base for
  3933 any algebraic development in Isabelle.  Currently covers group theory
  3934 (up to Sylow's theorem) and ring theory (Universal Property of
  3935 Univariate Polynomials).  Contributions welcome;
  3936 
  3937 * GroupTheory: deleted, since its material has been moved to Algebra;
  3938 
  3939 * Complex: new directory of the complex numbers with numeric constants,
  3940 nonstandard complex numbers, and some complex analysis, standard and
  3941 nonstandard (Jacques Fleuriot);
  3942 
  3943 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3944 
  3945 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3946 Fleuriot);
  3947 
  3948 * Real/HahnBanach: updated and adapted to locales;
  3949 
  3950 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3951 Gray and Kramer);
  3952 
  3953 * UNITY: added the Meier-Sanders theory of progress sets;
  3954 
  3955 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3956 as abstract algorithms, instantiated to the JVM;
  3957 
  3958 * Bali: Java source language formalization. Type system, operational
  3959 semantics, axiomatic semantics. Supported language features:
  3960 classes, interfaces, objects,virtual methods, static methods,
  3961 static/instance fields, arrays, access modifiers, definite
  3962 assignment, exceptions.
  3963 
  3964 
  3965 *** ZF ***
  3966 
  3967 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3968 universe, etc.);
  3969 
  3970 * Main ZF: virtually all theories converted to new-style format;
  3971 
  3972 
  3973 *** ML ***
  3974 
  3975 * Pure: Tactic.prove provides sane interface for internal proofs;
  3976 omits the infamous "standard" operation, so this is more appropriate
  3977 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3978 
  3979 * Pure: improved error reporting of simprocs;
  3980 
  3981 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3982 up simprocs;
  3983 
  3984 
  3985 *** Document preparation ***
  3986 
  3987 * uses \par instead of \\ for line breaks in theory text. This may
  3988 shift some page breaks in large documents. To get the old behaviour
  3989 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3990 
  3991 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3992 other packages
  3993 
  3994 * \<euro> now needs package babel/greek instead of marvosym (which
  3995 broke \Rightarrow)
  3996 
  3997 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3998 textcomp package)
  3999 
  4000 
  4001 
  4002 New in Isabelle2002 (March 2002)
  4003 --------------------------------
  4004 
  4005 *** Document preparation ***
  4006 
  4007 * greatly simplified document preparation setup, including more
  4008 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4009 instructive isatool mkdir; users should basically be able to get
  4010 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4011 users may run a separate document processing stage manually like this:
  4012 "isatool usedir -D output HOL Test && isatool document Test/output";
  4013 
  4014 * theory dependency graph may now be incorporated into documents;
  4015 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4016 with \includegraphics of LaTeX;
  4017 
  4018 * proper spacing of consecutive markup elements, especially text
  4019 blocks after section headings;
  4020 
  4021 * support bold style (for single symbols only), input syntax is like
  4022 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4023 
  4024 * \<bullet> is now output as bold \cdot by default, which looks much
  4025 better in printed text;
  4026 
  4027 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4028 note that these symbols are currently unavailable in Proof General /
  4029 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4030 
  4031 * isatool latex no longer depends on changed TEXINPUTS, instead
  4032 isatool document copies the Isabelle style files to the target
  4033 location;
  4034 
  4035 
  4036 *** Isar ***
  4037 
  4038 * Pure/Provers: improved proof by cases and induction;
  4039   - 'case' command admits impromptu naming of parameters (such as
  4040     "case (Suc n)");
  4041   - 'induct' method divinates rule instantiation from the inductive
  4042     claim; no longer requires excessive ?P bindings for proper
  4043     instantiation of cases;
  4044   - 'induct' method properly enumerates all possibilities of set/type
  4045     rules; as a consequence facts may be also passed through *type*
  4046     rules without further ado;
  4047   - 'induct' method now derives symbolic cases from the *rulified*
  4048     rule (before it used to rulify cases stemming from the internal
  4049     atomized version); this means that the context of a non-atomic
  4050     statement becomes is included in the hypothesis, avoiding the
  4051     slightly cumbersome show "PROP ?case" form;
  4052   - 'induct' may now use elim-style induction rules without chaining
  4053     facts, using ``missing'' premises from the goal state; this allows
  4054     rules stemming from inductive sets to be applied in unstructured
  4055     scripts, while still benefitting from proper handling of non-atomic
  4056     statements; NB: major inductive premises need to be put first, all
  4057     the rest of the goal is passed through the induction;
  4058   - 'induct' proper support for mutual induction involving non-atomic
  4059     rule statements (uses the new concept of simultaneous goals, see
  4060     below);
  4061   - append all possible rule selections, but only use the first
  4062     success (no backtracking);
  4063   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4064   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4065   - added 'print_induct_rules' (covered by help item in recent Proof
  4066     General versions);
  4067   - moved induct/cases attributes to Pure, methods to Provers;
  4068   - generic method setup instantiated for FOL and HOL;
  4069 
  4070 * Pure: support multiple simultaneous goal statements, for example
  4071 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4072 meta-level mechanism, this acts as if several individual goals had
  4073 been stated separately; in particular common proof methods need to be
  4074 repeated in order to cover all claims; note that a single elimination
  4075 step is *not* sufficient to establish the two conjunctions, so this
  4076 fails:
  4077 
  4078   assume "A & B" then have A and B ..   (*".." fails*)
  4079 
  4080 better use "obtain" in situations as above; alternative refer to
  4081 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4082 
  4083 * Pure: proper integration with ``locales''; unlike the original
  4084 version by Florian Kammller, Isar locales package high-level proof
  4085 contexts rather than raw logical ones (e.g. we admit to include
  4086 attributes everywhere); operations on locales include merge and
  4087 rename; support for implicit arguments (``structures''); simultaneous
  4088 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4089 some examples;
  4090 
  4091 * Pure: the following commands have been ``localized'', supporting a
  4092 target locale specification "(in name)": 'lemma', 'theorem',
  4093 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4094 stored both within the locale and at the theory level (exported and
  4095 qualified by the locale name);
  4096 
  4097 * Pure: theory goals may now be specified in ``long'' form, with
  4098 ad-hoc contexts consisting of arbitrary locale elements. for example
  4099 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4100 definitions may be given, too); the result is a meta-level rule with
  4101 the context elements being discharged in the obvious way;
  4102 
  4103 * Pure: new proof command 'using' allows to augment currently used
  4104 facts after a goal statement ('using' is syntactically analogous to
  4105 'apply', but acts on the goal's facts only); this allows chained facts
  4106 to be separated into parts given before and after a claim, as in
  4107 ``from a and b have C using d and e <proof>'';
  4108 
  4109 * Pure: renamed "antecedent" case to "rule_context";
  4110 
  4111 * Pure: new 'judgment' command records explicit information about the
  4112 object-logic embedding (used by several tools internally); no longer
  4113 use hard-wired "Trueprop";
  4114 
  4115 * Pure: added 'corollary' command;
  4116 
  4117 * Pure: fixed 'token_translation' command;
  4118 
  4119 * Pure: removed obsolete 'exported' attribute;
  4120 
  4121 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4122 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4123 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4124 
  4125 * Pure: method 'atomize' presents local goal premises as object-level
  4126 statements (atomic meta-level propositions); setup controlled via
  4127 rewrite rules declarations of 'atomize' attribute; example
  4128 application: 'induct' method with proper rule statements in improper
  4129 proof *scripts*;
  4130 
  4131 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4132 now consider the syntactic context of assumptions, giving a better
  4133 chance to get type-inference of the arguments right (this is
  4134 especially important for locales);
  4135 
  4136 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4137 mode;
  4138 
  4139 * Pure/obtain: the formal conclusion "thesis", being marked as
  4140 ``internal'', may no longer be reference directly in the text;
  4141 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4142 situations;
  4143 
  4144 * Pure: generic 'sym' attribute which declares a rule both as pure
  4145 'elim?' and for the 'symmetric' operation;
  4146 
  4147 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4148 text; the fixed correlation with particular command syntax has been
  4149 discontinued;
  4150 
  4151 * Pure: new method 'rules' is particularly well-suited for proof
  4152 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4153 but often produces more compact proof terms with less detours;
  4154 
  4155 * Pure/Provers/classical: simplified integration with pure rule
  4156 attributes and methods; the classical "intro?/elim?/dest?"
  4157 declarations coincide with the pure ones; the "rule" method no longer
  4158 includes classically swapped intros; "intro" and "elim" methods no
  4159 longer pick rules from the context; also got rid of ML declarations
  4160 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4161 INCOMPATIBILITY;
  4162 
  4163 * Provers/classical: attribute 'swapped' produces classical inversions
  4164 of introduction rules;
  4165 
  4166 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4167 rules instead of full simplifier context; 'iff' attribute handles
  4168 conditional rules;
  4169 
  4170 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4171 
  4172 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4173 "(permissive)" option to recover old behavior;
  4174 
  4175 * HOL: 'inductive' no longer features separate (collective) attributes
  4176 for 'intros' (was found too confusing);
  4177 
  4178 * HOL: properly declared induction rules less_induct and
  4179 wf_induct_rule;
  4180 
  4181 
  4182 *** HOL ***
  4183 
  4184 * HOL: moved over to sane numeral syntax; the new policy is as
  4185 follows:
  4186 
  4187   - 0 and 1 are polymorphic constants, which are defined on any
  4188   numeric type (nat, int, real etc.);
  4189 
  4190   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4191   binary representation internally;
  4192 
  4193   - type nat has special constructor Suc, and generally prefers Suc 0
  4194   over 1::nat and Suc (Suc 0) over 2::nat;
  4195 
  4196 This change may cause significant problems of INCOMPATIBILITY; here
  4197 are some hints on converting existing sources:
  4198 
  4199   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4200   entities, so expressions involving "-" (unary or binary minus) need
  4201   to be spaced properly;
  4202 
  4203   - existing occurrences of "1" may need to be constraint "1::nat" or
  4204   even replaced by Suc 0; similar for old "2";
  4205 
  4206   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4207 
  4208   - remove all special provisions on numerals in proofs;
  4209 
  4210 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4211 representation (depends on bin_arith_simps in the default context);
  4212 
  4213 * HOL: symbolic syntax for x^2 (numeral 2);
  4214 
  4215 * HOL: the class of all HOL types is now called "type" rather than
  4216 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4217 in axclass/classes, instance/arities, and (usually rare) occurrences
  4218 in typings (of consts etc.); internally the class is called
  4219 "HOL.type", ML programs should refer to HOLogic.typeS;
  4220 
  4221 * HOL/record package improvements:
  4222   - new derived operations "fields" to build a partial record section,
  4223     "extend" to promote a fixed record to a record scheme, and
  4224     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4225     declared as simp by default;
  4226   - shared operations ("more", "fields", etc.) now need to be always
  4227     qualified) --- potential INCOMPATIBILITY;
  4228   - removed "make_scheme" operations (use "make" with "extend") --
  4229     INCOMPATIBILITY;
  4230   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4231   - provides cases/induct rules for use with corresponding Isar
  4232     methods (for concrete records, record schemes, concrete more
  4233     parts, and schematic more parts -- in that order);
  4234   - internal definitions directly based on a light-weight abstract
  4235     theory of product types over typedef rather than datatype;
  4236 
  4237 * HOL: generic code generator for generating executable ML code from
  4238 specifications; specific support for HOL constructs such as inductive
  4239 datatypes and sets, as well as recursive functions; can be invoked
  4240 via 'generate_code' theory section;
  4241 
  4242 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4243 
  4244 * HOL: consolidated and renamed several theories.  In particular:
  4245         Ord.thy has been absorbed into HOL.thy
  4246         String.thy has been absorbed into List.thy
  4247 
  4248 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4249 (beware of argument permutation!);
  4250 
  4251 * HOL: linorder_less_split superseded by linorder_cases;
  4252 
  4253 * HOL/List: "nodups" renamed to "distinct";
  4254 
  4255 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4256 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4257   - Ex_def has changed, now need to use some_eq_ex
  4258 
  4259 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4260 in this (rare) case use:
  4261 
  4262   delSWrapper "split_all_tac"
  4263   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4264 
  4265 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4266 MAY FAIL;
  4267 
  4268 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4269 Isabelle's type classes, ^ on functions and relations has too general
  4270 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4271 necessary to attach explicit type constraints;
  4272 
  4273 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4274 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4275 renamed accordingly (eg "compI" -> "rel_compI").
  4276 
  4277 * HOL: syntax translations now work properly with numerals and records
  4278 expressions;
  4279 
  4280 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4281 of "lam" -- INCOMPATIBILITY;
  4282 
  4283 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4284 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4285 renamed "Product_Type.unit";
  4286 
  4287 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4288 
  4289 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4290 the "cases" method);
  4291 
  4292 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4293 Florian Kammller);
  4294 
  4295 * HOL/IMP: updated and converted to new-style theory format; several
  4296 parts turned into readable document, with proper Isar proof texts and
  4297 some explanations (by Gerwin Klein);
  4298 
  4299 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4300 
  4301 * HOL-Hyperreal is now a logic image;
  4302 
  4303 
  4304 *** HOLCF ***
  4305 
  4306 * Isar: consts/constdefs supports mixfix syntax for continuous
  4307 operations;
  4308 
  4309 * Isar: domain package adapted to new-style theory format, e.g. see
  4310 HOLCF/ex/Dnat.thy;
  4311 
  4312 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4313 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4314 lift.induct_tac, always use UU instead of Undef;
  4315 
  4316 * HOLCF/IMP: updated and converted to new-style theory;
  4317 
  4318 
  4319 *** ZF ***
  4320 
  4321 * Isar: proper integration of logic-specific tools and packages,
  4322 including theory commands '(co)inductive', '(co)datatype',
  4323 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4324 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4325 
  4326 * theory Main no longer includes AC; for the Axiom of Choice, base
  4327 your theory on Main_ZFC;
  4328 
  4329 * the integer library now covers quotients and remainders, with many
  4330 laws relating division to addition, multiplication, etc.;
  4331 
  4332 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4333 typeless version of the formalism;
  4334 
  4335 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4336 format;
  4337 
  4338 * ZF/Induct: new directory for examples of inductive definitions,
  4339 including theory Multiset for multiset orderings; converted to
  4340 new-style theory format;
  4341 
  4342 * ZF: many new theorems about lists, ordinals, etc.;
  4343 
  4344 
  4345 *** General ***
  4346 
  4347 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4348 variable proof controls level of detail: 0 = no proofs (only oracle
  4349 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4350 also ref manual for further ML interfaces;
  4351 
  4352 * Pure/axclass: removed obsolete ML interface
  4353 goal_subclass/goal_arity;
  4354 
  4355 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4356 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4357 separate tokens, so expressions involving minus need to be spaced
  4358 properly;
  4359 
  4360 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4361 rather than "infixl" or "infixr";
  4362 
  4363 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4364 sort constraint specifications in type inference; e.g. "x::_::foo"
  4365 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4366 type variable);
  4367 
  4368 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4369 control output of nested => (types); the default behavior is
  4370 "type_brackets";
  4371 
  4372 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4373 tokens into AST constants;
  4374 
  4375 * Pure/syntax: prefer later declarations of translations and print
  4376 translation functions; potential INCOMPATIBILITY: need to reverse
  4377 multiple declarations for same syntax element constant;
  4378 
  4379 * Pure/show_hyps reset by default (in accordance to existing Isar
  4380 practice);
  4381 
  4382 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4383 addSafter;
  4384 
  4385 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4386 as well;
  4387 
  4388 * system: tested support for MacOS X; should be able to get Isabelle +
  4389 Proof General to work in a plain Terminal after installing Poly/ML
  4390 (e.g. from the Isabelle distribution area) and GNU bash alone
  4391 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4392 support requires further installations, e.g. from
  4393 http://fink.sourceforge.net/);
  4394 
  4395 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4396 
  4397 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4398 of 40 MB), cf. ML_OPTIONS;
  4399 
  4400 * system: Proof General keywords specification is now part of the
  4401 Isabelle distribution (see etc/isar-keywords.el);
  4402 
  4403 * system: support for persistent Proof General sessions (refrain from
  4404 outdating all loaded theories on startup); user may create writable
  4405 logic images like this: ``isabelle -q HOL Test'';
  4406 
  4407 * system: smart selection of Isabelle process versus Isabelle
  4408 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4409 run both "isabelle" and "Isabelle" even if file names are badly
  4410 damaged (executable inspects the case of the first letter of its own
  4411 name); added separate "isabelle-process" and "isabelle-interface";
  4412 
  4413 * system: refrain from any attempt at filtering input streams; no
  4414 longer support ``8bit'' encoding of old isabelle font, instead proper
  4415 iso-latin characters may now be used; the related isatools
  4416 "symbolinput" and "nonascii" have disappeared as well;
  4417 
  4418 * system: removed old "xterm" interface (the print modes "xterm" and
  4419 "xterm_color" are still available for direct use in a suitable
  4420 terminal);
  4421 
  4422 
  4423 
  4424 New in Isabelle99-2 (February 2001)
  4425 -----------------------------------
  4426 
  4427 *** Overview of INCOMPATIBILITIES ***
  4428 
  4429 * HOL: please note that theories in the Library and elsewhere often use the
  4430 new-style (Isar) format; to refer to their theorems in an ML script you must
  4431 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4432 
  4433 * HOL: inductive package no longer splits induction rule aggressively,
  4434 but only as far as specified by the introductions given; the old
  4435 format may be recovered via ML function complete_split_rule or attribute
  4436 'split_rule (complete)';
  4437 
  4438 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4439 gfp_Tarski to gfp_unfold;
  4440 
  4441 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4442 
  4443 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4444 relation); infix "^^" has been renamed "``"; infix "``" has been
  4445 renamed "`"; "univalent" has been renamed "single_valued";
  4446 
  4447 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4448 operation;
  4449 
  4450 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4451 
  4452 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4453 
  4454 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4455 consequence, it is no longer monotonic wrt. the local goal context
  4456 (which is now passed through the inductive cases);
  4457 
  4458 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4459 \<gg> to \<ggreater>;
  4460 
  4461 
  4462 *** Document preparation ***
  4463 
  4464 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4465 available: are "it" for near math-mode best-style output, "sl" for
  4466 slanted text style, and "tt" for plain type-writer; if no
  4467 \isabellestyle command is given, output is according to slanted
  4468 type-writer);
  4469 
  4470 * support sub/super scripts (for single symbols only), input syntax is
  4471 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4472 
  4473 * some more standard symbols; see Appendix A of the system manual for
  4474 the complete list of symbols defined in isabellesym.sty;
  4475 
  4476 * improved isabelle style files; more abstract symbol implementation
  4477 (should now use \isamath{...} and \isatext{...} in custom symbol
  4478 definitions);
  4479 
  4480 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4481 state; Note that presentation of goal states does not conform to
  4482 actual human-readable proof documents.  Please do not include goal
  4483 states into document output unless you really know what you are doing!
  4484 
  4485 * proper indentation of antiquoted output with proportional LaTeX
  4486 fonts;
  4487 
  4488 * no_document ML operator temporarily disables LaTeX document
  4489 generation;
  4490 
  4491 * isatool unsymbolize tunes sources for plain ASCII communication;
  4492 
  4493 
  4494 *** Isar ***
  4495 
  4496 * Pure: Isar now suffers initial goal statements to contain unbound
  4497 schematic variables (this does not conform to actual readable proof
  4498 documents, due to unpredictable outcome and non-compositional proof
  4499 checking); users who know what they are doing may use schematic goals
  4500 for Prolog-style synthesis of proven results;
  4501 
  4502 * Pure: assumption method (an implicit finishing) now handles actual
  4503 rules as well;
  4504 
  4505 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4506 initial goal, declare "that" only as Pure intro (only for single
  4507 steps); the "that" rule assumption may now be involved in implicit
  4508 finishing, thus ".." becomes a feasible for trivial obtains;
  4509 
  4510 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4511 instance proofs may be performed by "..";
  4512 
  4513 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4514 statements as well;
  4515 
  4516 * Pure: more robust selection of calculational rules;
  4517 
  4518 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4519 rule (as well as the assumption rule);
  4520 
  4521 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4522 lemmas, using the graph browser tool;
  4523 
  4524 * Pure: predict failure of "show" in interactive mode;
  4525 
  4526 * Pure: 'thms_containing' now takes actual terms as arguments;
  4527 
  4528 * HOL: improved method 'induct' --- now handles non-atomic goals
  4529 (potential INCOMPATIBILITY); tuned error handling;
  4530 
  4531 * HOL: cases and induct rules now provide explicit hints about the
  4532 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4533 any remaining facts are inserted into the goal verbatim;
  4534 
  4535 * HOL: local contexts (aka cases) may now contain term bindings as
  4536 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4537 the result to be shown in each case;
  4538 
  4539 * HOL: added 'recdef_tc' command;
  4540 
  4541 * isatool convert assists in eliminating legacy ML scripts;
  4542 
  4543 
  4544 *** HOL ***
  4545 
  4546 * HOL/Library: a collection of generic theories to be used together
  4547 with main HOL; the theory loader path already includes this directory
  4548 by default; the following existing theories have been moved here:
  4549 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4550 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4551 
  4552 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4553 modelling and verification task performed in Isabelle/HOL +
  4554 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4555 
  4556 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4557 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4558 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4559 'domain', this makes the theory consistent with mathematical
  4560 literature;
  4561 
  4562 * HOL basics: added overloaded operations "inverse" and "divide"
  4563 (infix "/"), syntax for generic "abs" operation, generic summation
  4564 operator \<Sum>;
  4565 
  4566 * HOL/typedef: simplified package, provide more useful rules (see also
  4567 HOL/subset.thy);
  4568 
  4569 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4570 now expressed as a proper nested rule (old-style tactic scripts may
  4571 require atomize_strip_tac to cope with non-atomic premises);
  4572 
  4573 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4574 to "split_conv" (old name still available for compatibility);
  4575 
  4576 * HOL: improved concrete syntax for strings (e.g. allows translation
  4577 rules with string literals);
  4578 
  4579 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4580  and Fleuriot's mechanization of analysis, including the transcendental
  4581  functions for the reals;
  4582 
  4583 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4584 
  4585 
  4586 *** CTT ***
  4587 
  4588 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4589 "lam" is displayed as TWO lambda-symbols
  4590 
  4591 * CTT: theory Main now available, containing everything (that is, Bool
  4592 and Arith);
  4593 
  4594 
  4595 *** General ***
  4596 
  4597 * Pure: the Simplifier has been implemented properly as a derived rule
  4598 outside of the actual kernel (at last!); the overall performance
  4599 penalty in practical applications is about 50%, while reliability of
  4600 the Isabelle inference kernel has been greatly improved;
  4601 
  4602 * print modes "brackets" and "no_brackets" control output of nested =>
  4603 (types) and ==> (props); the default behaviour is "brackets";
  4604 
  4605 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4606 as assumptions as well;
  4607 
  4608 * system: support Poly/ML 4.0;
  4609 
  4610 * system: isatool install handles KDE version 1 or 2;
  4611 
  4612 
  4613 
  4614 New in Isabelle99-1 (October 2000)
  4615 ----------------------------------
  4616 
  4617 *** Overview of INCOMPATIBILITIES ***
  4618 
  4619 * HOL: simplification of natural numbers is much changed; to partly
  4620 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4621 issue the following ML commands:
  4622 
  4623   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4624   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4625 
  4626 * HOL: simplification no longer dives into case-expressions; this is
  4627 controlled by "t.weak_case_cong" for each datatype t;
  4628 
  4629 * HOL: nat_less_induct renamed to less_induct;
  4630 
  4631 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4632 fixsome to patch .thy and .ML sources automatically;
  4633 
  4634   select_equality  -> some_equality
  4635   select_eq_Ex     -> some_eq_ex
  4636   selectI2EX       -> someI2_ex
  4637   selectI2         -> someI2
  4638   selectI          -> someI
  4639   select1_equality -> some1_equality
  4640   Eps_sym_eq       -> some_sym_eq_trivial
  4641   Eps_eq           -> some_eq_trivial
  4642 
  4643 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4644 
  4645 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4646 instead);
  4647 
  4648 * HOL: the recursion equations generated by 'recdef' are now called
  4649 f.simps instead of f.rules;
  4650 
  4651 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4652 
  4653 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4654 sometimes be needed;
  4655 
  4656 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4657 
  4658 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4659 
  4660 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4661 product is now "<*>" instead of "Times"; the lexicographic product is
  4662 now "<*lex*>" instead of "**";
  4663 
  4664 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4665 of main HOL, but was unused); better use HOL's datatype package;
  4666 
  4667 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4668 the old syntax may be recovered as follows:
  4669 
  4670   syntax (symbols)
  4671     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4672       (infixl "\\<oplus>" 100)
  4673 
  4674 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4675 
  4676 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4677 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4678 internally;
  4679 
  4680 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4681 changed from A/r to A//r;
  4682 
  4683 * ZF: new treatment of arithmetic (nat & int) may break some old
  4684 proofs;
  4685 
  4686 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4687 rulify -> rule_format, elimify -> elim_format, ...);
  4688 
  4689 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4690 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4691 should have to change intro!! to intro? only); replaced "delrule" by
  4692 "rule del";
  4693 
  4694 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4695 
  4696 * Provers: strengthened force_tac by using new first_best_tac;
  4697 
  4698 * LaTeX document preparation: several changes of isabelle.sty (see
  4699 lib/texinputs);
  4700 
  4701 
  4702 *** Document preparation ***
  4703 
  4704 * formal comments (text blocks etc.) in new-style theories may now
  4705 contain antiquotations of thm/prop/term/typ/text to be presented
  4706 according to latex print mode; concrete syntax is like this:
  4707 @{term[show_types] "f(x) = a + x"};
  4708 
  4709 * isatool mkdir provides easy setup of Isabelle session directories,
  4710 including proper document sources;
  4711 
  4712 * generated LaTeX sources are now deleted after successful run
  4713 (isatool document -c); may retain a copy somewhere else via -D option
  4714 of isatool usedir;
  4715 
  4716 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4717 style files, achieving self-contained LaTeX sources and simplifying
  4718 LaTeX debugging;
  4719 
  4720 * old-style theories now produce (crude) LaTeX output as well;
  4721 
  4722 * browser info session directories are now self-contained (may be put
  4723 on WWW server seperately); improved graphs of nested sessions; removed
  4724 graph for 'all sessions';
  4725 
  4726 * several improvements in isabelle style files; \isabellestyle{it}
  4727 produces fake math mode output; \isamarkupheader is now \section by
  4728 default; see lib/texinputs/isabelle.sty etc.;
  4729 
  4730 
  4731 *** Isar ***
  4732 
  4733 * Isar/Pure: local results and corresponding term bindings are now
  4734 subject to Hindley-Milner polymorphism (similar to ML); this
  4735 accommodates incremental type-inference very nicely;
  4736 
  4737 * Isar/Pure: new derived language element 'obtain' supports
  4738 generalized existence reasoning;
  4739 
  4740 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4741 support accumulation of results, without applying any rules yet;
  4742 useful to collect intermediate results without explicit name
  4743 references, and for use with transitivity rules with more than 2
  4744 premises;
  4745 
  4746 * Isar/Pure: scalable support for case-analysis type proofs: new
  4747 'case' language element refers to local contexts symbolically, as
  4748 produced by certain proof methods; internally, case names are attached
  4749 to theorems as "tags";
  4750 
  4751 * Isar/Pure: theory command 'hide' removes declarations from
  4752 class/type/const name spaces;
  4753 
  4754 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4755 indicate potential overloading;
  4756 
  4757 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4758 
  4759 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4760 "{a,b,c}" instead of {a,b,c};
  4761 
  4762 * Isar/Pure now provides its own version of intro/elim/dest
  4763 attributes; useful for building new logics, but beware of confusion
  4764 with the version in Provers/classical;
  4765 
  4766 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4767 case name 'antecedent';
  4768 
  4769 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4770 to the current context is now done automatically);
  4771 
  4772 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4773 for definining proof methods in ML;
  4774 
  4775 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4776 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4777 most cases, one should have to change intro!! to intro? only);
  4778 replaced "delrule" by "rule del";
  4779 
  4780 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4781 'symmetric' attribute (the latter supercedes [RS sym]);
  4782 
  4783 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4784 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4785 well (including splits);
  4786 
  4787 * Isar/Provers: Simplifier and Classical methods now support all kind
  4788 of modifiers used in the past, including 'cong', 'iff', etc.
  4789 
  4790 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4791 of Simplifier and Classical reasoner);
  4792 
  4793 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4794 now support named cases; major packages (inductive, datatype, primrec,
  4795 recdef) support case names and properly name parameters;
  4796 
  4797 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4798 monotonicity conditions are extracted to be proven at end of
  4799 calculations;
  4800 
  4801 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4802 method anyway;
  4803 
  4804 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4805 split_if split_if_asm; datatype package provides theorems foo.splits =
  4806 foo.split foo.split_asm for each datatype;
  4807 
  4808 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4809 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4810 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4811 use "(cases (simplified))" method in proper proof texts);
  4812 
  4813 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4814 
  4815 * Isar: names of theorems etc. may be natural numbers as well;
  4816 
  4817 * Isar: 'pr' command: optional arguments for goals_limit and
  4818 ProofContext.prems_limit; no longer prints theory contexts, but only
  4819 proof states;
  4820 
  4821 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4822 additional print modes to be specified; e.g. "pr(latex)" will print
  4823 proof state according to the Isabelle LaTeX style;
  4824 
  4825 * Isar: improved support for emulating tactic scripts, including proof
  4826 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4827 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4828 (for HOL datatypes);
  4829 
  4830 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4831 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4832 'proof method scripts' have to be in depth-first order;
  4833 
  4834 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4835 
  4836 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4837 should instead use individual commands for printing items
  4838 (print_commands, print_methods etc.);
  4839 
  4840 * Isar: added 'nothing' --- the empty list of theorems;
  4841 
  4842 
  4843 *** HOL ***
  4844 
  4845 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4846 corresponding virtual machine and a specification of its bytecode
  4847 verifier and a lightweight bytecode verifier, including proofs of
  4848 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4849 Cornelia Pusch (see also the homepage of project Bali at
  4850 http://isabelle.in.tum.de/Bali/);
  4851 
  4852 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4853 Clemens Ballarin;
  4854 
  4855 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4856 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4857 Rasmussen;
  4858 
  4859 * HOL/Lattice: fundamental concepts of lattice theory and order
  4860 structures, including duals, properties of bounds versus algebraic
  4861 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4862 Theorem for complete lattices etc.; may also serve as a demonstration
  4863 for abstract algebraic reasoning using axiomatic type classes, and
  4864 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4865 
  4866 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4867 von Oheimb;
  4868 
  4869 * HOL/IMPP: extension of IMP with local variables and mutually
  4870 recursive procedures, by David von Oheimb;
  4871 
  4872 * HOL/Lambda: converted into new-style theory and document;
  4873 
  4874 * HOL/ex/Multiquote: example of multiple nested quotations and
  4875 anti-quotations -- basically a generalized version of de-Bruijn
  4876 representation; very useful in avoiding lifting of operations;
  4877 
  4878 * HOL/record: added general record equality rule to simpset; fixed
  4879 select-update simplification procedure to handle extended records as
  4880 well; admit "r" as field name;
  4881 
  4882 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4883 other numeric types and also as the identity of groups, rings, etc.;
  4884 
  4885 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4886 Types nat and int belong to this axclass;
  4887 
  4888 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4889    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4890    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4891   two terms #m*u and #n*u are replaced by #(m+n)*u
  4892     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4893   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4894     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4895 
  4896 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4897 powerful prover for predicate logic but knows nothing of clasets; see
  4898 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4899 
  4900 * HOL: new version of "case_tac" subsumes both boolean case split and
  4901 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4902 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4903 
  4904 * HOL: simplification no longer dives into case-expressions: only the
  4905 selector expression is simplified, but not the remaining arms; to
  4906 enable full simplification of case-expressions for datatype t, you may
  4907 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4908 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4909 
  4910 * HOL/recdef: the recursion equations generated by 'recdef' for
  4911 function 'f' are now called f.simps instead of f.rules; if all
  4912 termination conditions are proved automatically, these simplification
  4913 rules are added to the simpset, as in primrec; rules may be named
  4914 individually as well, resulting in a separate list of theorems for
  4915 each equation;
  4916 
  4917 * HOL/While is a new theory that provides a while-combinator. It
  4918 permits the definition of tail-recursive functions without the
  4919 provision of a termination measure. The latter is necessary once the
  4920 invariant proof rule for while is applied.
  4921 
  4922 * HOL: new (overloaded) notation for the set of elements below/above
  4923 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4924 
  4925 * HOL: theorems impI, allI, ballI bound as "strip";
  4926 
  4927 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4928 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4929 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4930 
  4931 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4932 
  4933 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4934 main HOL, but was unused);
  4935 
  4936 * HOL: fewer consts declared as global (e.g. have to refer to
  4937 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4938 
  4939 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4940 in case of overlap with user translations (e.g. judgements over
  4941 tuples); (note that the underlying logical represenation is still
  4942 bogus);
  4943 
  4944 
  4945 *** ZF ***
  4946 
  4947 * ZF: simplification automatically cancels common terms in arithmetic
  4948 expressions over nat and int;
  4949 
  4950 * ZF: new treatment of nat to minimize type-checking: all operators
  4951 coerce their operands to a natural number using the function natify,
  4952 making the algebraic laws unconditional;
  4953 
  4954 * ZF: as above, for int: operators coerce their operands to an integer
  4955 using the function intify;
  4956 
  4957 * ZF: the integer library now contains many of the usual laws for the
  4958 orderings, including $<=, and monotonicity laws for $+ and $*;
  4959 
  4960 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4961 simplification;
  4962 
  4963 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4964 to the simplifier and classical reasoner simultaneously;
  4965 
  4966 
  4967 *** General ***
  4968 
  4969 * Provers: blast_tac now handles actual object-logic rules as
  4970 assumptions; note that auto_tac uses blast_tac internally as well;
  4971 
  4972 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4973 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4974 
  4975 * Provers: delrules now handles destruct rules as well (no longer need
  4976 explicit make_elim);
  4977 
  4978 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4979   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4980 use instead the strong form,
  4981   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4982 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4983 from destruct-rules;
  4984 
  4985 * Provers: Simplifier.easy_setup provides a fast path to basic
  4986 Simplifier setup for new object-logics;
  4987 
  4988 * Pure: AST translation rules no longer require constant head on LHS;
  4989 
  4990 * Pure: improved name spaces: ambiguous output is qualified; support
  4991 for hiding of names;
  4992 
  4993 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4994 XSYMBOL_HOME; no longer need to do manual configuration in most
  4995 situations;
  4996 
  4997 * system: compression of ML heaps images may now be controlled via -c
  4998 option of isabelle and isatool usedir (currently only observed by
  4999 Poly/ML);
  5000 
  5001 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5002 useful for remote X11);
  5003 
  5004 * system: provide TAGS file for Isabelle sources;
  5005 
  5006 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5007 order;
  5008 
  5009 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5010 timing flag supersedes proof_timing and Toplevel.trace;
  5011 
  5012 * ML: new combinators |>> and |>>> for incremental transformations
  5013 with secondary results (e.g. certain theory extensions):
  5014 
  5015 * ML: PureThy.add_defs gets additional argument to indicate potential
  5016 overloading (usually false);
  5017 
  5018 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5019 results;
  5020 
  5021 
  5022 
  5023 New in Isabelle99 (October 1999)
  5024 --------------------------------
  5025 
  5026 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5027 
  5028 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5029 are no longer simplified.  (This allows the simplifier to unfold recursive
  5030 functional programs.)  To restore the old behaviour, declare
  5031 
  5032     Delcongs [if_weak_cong];
  5033 
  5034 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5035 complement;
  5036 
  5037 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5038 
  5039 * HOL/datatype: mutual_induct_tac no longer exists --
  5040   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5041 
  5042 * HOL/typedef: fixed type inference for representing set; type
  5043 arguments now have to occur explicitly on the rhs as type constraints;
  5044 
  5045 * ZF: The con_defs part of an inductive definition may no longer refer
  5046 to constants declared in the same theory;
  5047 
  5048 * HOL, ZF: the function mk_cases, generated by the inductive
  5049 definition package, has lost an argument.  To simplify its result, it
  5050 uses the default simpset instead of a supplied list of theorems.
  5051 
  5052 * HOL/List: the constructors of type list are now Nil and Cons;
  5053 
  5054 * Simplifier: the type of the infix ML functions
  5055         setSSolver addSSolver setSolver addSolver
  5056 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5057 for packaging solvers. A solver is created via
  5058         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5059 where the string argument is only a comment.
  5060 
  5061 
  5062 *** Proof tools ***
  5063 
  5064 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5065 decision procedure for linear arithmetic. Currently it is used for
  5066 types `nat', `int', and `real' in HOL (see below); it can, should and
  5067 will be instantiated for other types and logics as well.
  5068 
  5069 * The simplifier now accepts rewrite rules with flexible heads, eg
  5070      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5071   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5072   matching.
  5073 
  5074 
  5075 *** General ***
  5076 
  5077 * New Isabelle/Isar subsystem provides an alternative to traditional
  5078 tactical theorem proving; together with the ProofGeneral/isar user
  5079 interface it offers an interactive environment for developing human
  5080 readable proof documents (Isar == Intelligible semi-automated
  5081 reasoning); for further information see isatool doc isar-ref,
  5082 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5083 
  5084 * improved and simplified presentation of theories: better HTML markup
  5085 (including colors), graph views in several sizes; isatool usedir now
  5086 provides a proper interface for user theories (via -P option); actual
  5087 document preparation based on (PDF)LaTeX is available as well (for
  5088 new-style theories only); see isatool doc system for more information;
  5089 
  5090 * native support for Proof General, both for classic Isabelle and
  5091 Isabelle/Isar;
  5092 
  5093 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5094 using the graph browser tool;
  5095 
  5096 * Isabelle manuals now also available as PDF;
  5097 
  5098 * theory loader rewritten from scratch (may not be fully
  5099 bug-compatible); old loadpath variable has been replaced by show_path,
  5100 add_path, del_path, reset_path functions; new operations such as
  5101 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5102 isatool doc ref);
  5103 
  5104 * improved isatool install: option -k creates KDE application icon,
  5105 option -p DIR installs standalone binaries;
  5106 
  5107 * added ML_PLATFORM setting (useful for cross-platform installations);
  5108 more robust handling of platform specific ML images for SML/NJ;
  5109 
  5110 * the settings environment is now statically scoped, i.e. it is never
  5111 created again in sub-processes invoked from isabelle, isatool, or
  5112 Isabelle;
  5113 
  5114 * path element specification '~~' refers to '$ISABELLE_HOME';
  5115 
  5116 * in locales, the "assumes" and "defines" parts may be omitted if
  5117 empty;
  5118 
  5119 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5120 long arrows);
  5121 
  5122 * new print_mode "HTML";
  5123 
  5124 * new flag show_tags controls display of tags of theorems (which are
  5125 basically just comments that may be attached by some tools);
  5126 
  5127 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5128 mode and goal output format:
  5129 
  5130 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5131 244c244
  5132 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5133 ---
  5134 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5135 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5136 181c181
  5137 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5138 ---
  5139 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5140 
  5141 * function bind_thms stores lists of theorems (cf. bind_thm);
  5142 
  5143 * new shorthand tactics ftac, eatac, datac, fatac;
  5144 
  5145 * qed (and friends) now accept "" as result name; in that case the
  5146 theorem is not stored, but proper checks and presentation of the
  5147 result still apply;
  5148 
  5149 * theorem database now also indexes constants "Trueprop", "all",
  5150 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5151 
  5152 
  5153 *** HOL ***
  5154 
  5155 ** HOL arithmetic **
  5156 
  5157 * There are now decision procedures for linear arithmetic over nat and
  5158 int:
  5159 
  5160 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5161 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5162 are treated as atomic; subformulae not involving type `nat' or `int'
  5163 are ignored; quantified subformulae are ignored unless they are
  5164 positive universal or negative existential. The tactic has to be
  5165 invoked by hand and can be a little bit slow. In particular, the
  5166 running time is exponential in the number of occurrences of `min' and
  5167 `max', and `-' on `nat'.
  5168 
  5169 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5170 (negated) (in)equalities among the premises and the conclusion into
  5171 account (i.e. no compound formulae) and does not know about `min' and
  5172 `max', and `-' on `nat'. It is fast and is used automatically by the
  5173 simplifier.
  5174 
  5175 NB: At the moment, these decision procedures do not cope with mixed
  5176 nat/int formulae where the two parts interact, such as `m < n ==>
  5177 int(m) < int(n)'.
  5178 
  5179 * HOL/Numeral provides a generic theory of numerals (encoded
  5180 efficiently as bit strings); setup for types nat/int/real is in place;
  5181 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5182 int, existing theories and proof scripts may require a few additional
  5183 type constraints;
  5184 
  5185 * integer division and remainder can now be performed on constant
  5186 arguments;
  5187 
  5188 * many properties of integer multiplication, division and remainder
  5189 are now available;
  5190 
  5191 * An interface to the Stanford Validity Checker (SVC) is available through the
  5192 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5193 are proved automatically.  SVC must be installed separately, and its results
  5194 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5195 invocation of the underlying oracle).  For SVC see
  5196   http://verify.stanford.edu/SVC
  5197 
  5198 * IsaMakefile: the HOL-Real target now builds an actual image;
  5199 
  5200 
  5201 ** HOL misc **
  5202 
  5203 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5204 (in Isabelle/Isar) -- by Gertrud Bauer;
  5205 
  5206 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5207 analysis for assembly languages with subtypes;
  5208 
  5209 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5210 -- avoids syntactic ambiguities and treats state, transition, and
  5211 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5212 changed syntax and (many) tactics;
  5213 
  5214 * HOL/inductive: Now also handles more general introduction rules such
  5215   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5216   theorems are now maintained within the theory (maintained via the
  5217   "mono" attribute);
  5218 
  5219 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5220   (using function types) such as
  5221 
  5222   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5223 
  5224 * HOL/record: record_simproc (part of the default simpset) takes care
  5225 of selectors applied to updated records; record_split_tac is no longer
  5226 part of the default claset; update_defs may now be removed from the
  5227 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5228 
  5229   claset_ref () := claset() addSWrapper record_split_wrapper;
  5230   Delsimprocs [record_simproc]
  5231 
  5232 * HOL/typedef: fixed type inference for representing set; type
  5233 arguments now have to occur explicitly on the rhs as type constraints;
  5234 
  5235 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5236 names rather than an ML expression;
  5237 
  5238 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5239 supplied later.  Program schemes can be defined, such as
  5240     "While B C s = (if B s then While B C (C s) else s)"
  5241 where the well-founded relation can be chosen after B and C have been given.
  5242 
  5243 * HOL/List: the constructors of type list are now Nil and Cons;
  5244 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5245 course, ML tools referring to List.list.op # etc. have to be adapted;
  5246 
  5247 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5248 disabled by default; run isabelle with option -m HOL to get back to
  5249 the original Gordon/HOL-style output;
  5250 
  5251 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5252 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5253 
  5254 * HOL basic syntax simplified (more orthogonal): all variants of
  5255 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5256 Eps operator is provided as well: "SOME x. P[x]";
  5257 
  5258 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5259 
  5260 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5261 thus available for user theories;
  5262 
  5263 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5264 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5265 time;
  5266 
  5267 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5268 several times and then mp;
  5269 
  5270 
  5271 *** LK ***
  5272 
  5273 * the notation <<...>> is now available as a notation for sequences of
  5274 formulas;
  5275 
  5276 * the simplifier is now installed
  5277 
  5278 * the axiom system has been generalized (thanks to Soren Heilmann)
  5279 
  5280 * the classical reasoner now has a default rule database
  5281 
  5282 
  5283 *** ZF ***
  5284 
  5285 * new primrec section allows primitive recursive functions to be given
  5286 directly (as in HOL) over datatypes and the natural numbers;
  5287 
  5288 * new tactics induct_tac and exhaust_tac for induction (or case
  5289 analysis) over datatypes and the natural numbers;
  5290 
  5291 * the datatype declaration of type T now defines the recursor T_rec;
  5292 
  5293 * simplification automatically does freeness reasoning for datatype
  5294 constructors;
  5295 
  5296 * automatic type-inference, with AddTCs command to insert new
  5297 type-checking rules;
  5298 
  5299 * datatype introduction rules are now added as Safe Introduction rules
  5300 to the claset;
  5301 
  5302 * the syntax "if P then x else y" is now available in addition to
  5303 if(P,x,y);
  5304 
  5305 
  5306 *** Internal programming interfaces ***
  5307 
  5308 * tuned simplifier trace output; new flag debug_simp;
  5309 
  5310 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5311 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5312 
  5313 * AxClass.axclass_tac lost the theory argument;
  5314 
  5315 * tuned current_goals_markers semantics: begin / end goal avoids
  5316 printing empty lines;
  5317 
  5318 * removed prs and prs_fn hook, which was broken because it did not
  5319 include \n in its semantics, forcing writeln to add one
  5320 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5321 string -> unit if you really want to output text without newline;
  5322 
  5323 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5324 plain output, interface builders may have to enable 'isabelle_font'
  5325 mode to get Isabelle font glyphs as before;
  5326 
  5327 * refined token_translation interface; INCOMPATIBILITY: output length
  5328 now of type real instead of int;
  5329 
  5330 * theory loader actions may be traced via new ThyInfo.add_hook
  5331 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5332 your own database of information attached to *whole* theories -- as
  5333 opposed to intra-theory data slots offered via TheoryDataFun;
  5334 
  5335 * proper handling of dangling sort hypotheses (at last!);
  5336 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5337 extra sort hypotheses that can be witnessed from the type signature;
  5338 the force_strip_shyps flag is gone, any remaining shyps are simply
  5339 left in the theorem (with a warning issued by strip_shyps_warning);
  5340 
  5341 
  5342 
  5343 New in Isabelle98-1 (October 1998)
  5344 ----------------------------------
  5345 
  5346 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5347 
  5348 * several changes of automated proof tools;
  5349 
  5350 * HOL: major changes to the inductive and datatype packages, including
  5351 some minor incompatibilities of theory syntax;
  5352 
  5353 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5354 called `inj_on';
  5355 
  5356 * HOL: removed duplicate thms in Arith:
  5357   less_imp_add_less  should be replaced by  trans_less_add1
  5358   le_imp_add_le      should be replaced by  trans_le_add1
  5359 
  5360 * HOL: unary minus is now overloaded (new type constraints may be
  5361 required);
  5362 
  5363 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5364 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5365 now taken as an integer constant.
  5366 
  5367 * Pure: ML function 'theory_of' renamed to 'theory';
  5368 
  5369 
  5370 *** Proof tools ***
  5371 
  5372 * Simplifier:
  5373   1. Asm_full_simp_tac is now more aggressive.
  5374      1. It will sometimes reorient premises if that increases their power to
  5375         simplify.
  5376      2. It does no longer proceed strictly from left to right but may also
  5377         rotate premises to achieve further simplification.
  5378      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5379      old Asm_full_simp_tac in that it does not rotate premises.
  5380   2. The simplifier now knows a little bit about nat-arithmetic.
  5381 
  5382 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5383 allows for selected deletion of wrappers, by introduction of names for
  5384 wrapper functionals.  This implies that addbefore, addSbefore,
  5385 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5386 and that adding two tactics with the same name overwrites the first
  5387 one (emitting a warning).
  5388   type wrapper = (int -> tactic) -> (int -> tactic)
  5389   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5390   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5391   delWrapper, delSWrapper: claset *  string            -> claset
  5392   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5393 
  5394 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5395 semantics; addbefore now affects only the unsafe part of step_tac
  5396 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5397 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5398 by Force_tac;
  5399 
  5400 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5401 compWrapper; added safe wrapper (and access functions for it);
  5402 
  5403 * HOL/split_all_tac is now much faster and fails if there is nothing
  5404 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5405 and the names of the automatically generated variables have changed.
  5406 split_all_tac has moved within claset() from unsafe wrappers to safe
  5407 wrappers, which means that !!-bound variables are split much more
  5408 aggressively, and safe_tac and clarify_tac now split such variables.
  5409 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5410 Note: the same holds for record_split_tac, which does the job of
  5411 split_all_tac for record fields.
  5412 
  5413 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5414 permanently to the default simpset using Addsplits just like
  5415 Addsimps. They can be removed via Delsplits just like
  5416 Delsimps. Lower-case versions are also available.
  5417 
  5418 * HOL/Simplifier: The rule split_if is now part of the default
  5419 simpset. This means that the simplifier will eliminate all occurrences
  5420 of if-then-else in the conclusion of a goal. To prevent this, you can
  5421 either remove split_if completely from the default simpset by
  5422 `Delsplits [split_if]' or remove it in a specific call of the
  5423 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5424 other case splitting rules to/from the default simpset: every datatype
  5425 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5426 t is the name of the datatype).
  5427 
  5428 * Classical reasoner / Simplifier combination: new force_tac (and
  5429 derivatives Force_tac, force) combines rewriting and classical
  5430 reasoning (and whatever other tools) similarly to auto_tac, but is
  5431 aimed to solve the given subgoal completely.
  5432 
  5433 
  5434 *** General ***
  5435 
  5436 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5437 and `goalw': the theory is no longer needed as an explicit argument -
  5438 the current theory context is used; assumptions are no longer returned
  5439 at the ML-level unless one of them starts with ==> or !!; it is
  5440 recommended to convert to these new commands using isatool fixgoal
  5441 (backup your sources first!);
  5442 
  5443 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5444 the current theory context, and 'theory' to lookup stored theories;
  5445 
  5446 * new theory section 'locale' for declaring constants, assumptions and
  5447 definitions that have local scope;
  5448 
  5449 * new theory section 'nonterminals' for purely syntactic types;
  5450 
  5451 * new theory section 'setup' for generic ML setup functions
  5452 (e.g. package initialization);
  5453 
  5454 * the distribution now includes Isabelle icons: see
  5455 lib/logo/isabelle-{small,tiny}.xpm;
  5456 
  5457 * isatool install - install binaries with absolute references to
  5458 ISABELLE_HOME/bin;
  5459 
  5460 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5461 
  5462 * print mode 'emacs' reserved for Isamode;
  5463 
  5464 * support multiple print (ast) translations per constant name;
  5465 
  5466 * theorems involving oracles are now printed with a suffixed [!];
  5467 
  5468 
  5469 *** HOL ***
  5470 
  5471 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5472 
  5473 * HOL/inductive package reorganized and improved: now supports mutual
  5474 definitions such as
  5475 
  5476   inductive EVEN ODD
  5477     intrs
  5478       null "0 : EVEN"
  5479       oddI "n : EVEN ==> Suc n : ODD"
  5480       evenI "n : ODD ==> Suc n : EVEN"
  5481 
  5482 new theorem list "elims" contains an elimination rule for each of the
  5483 recursive sets; inductive definitions now handle disjunctive premises
  5484 correctly (also ZF);
  5485 
  5486 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5487 "mutual_induct" no longer exists - the induction rule is always
  5488 contained in "induct";
  5489 
  5490 
  5491 * HOL/datatype package re-implemented and greatly improved: now
  5492 supports mutually recursive datatypes such as
  5493 
  5494   datatype
  5495     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5496             | SUM ('a aexp) ('a aexp)
  5497             | DIFF ('a aexp) ('a aexp)
  5498             | NUM 'a
  5499   and
  5500     'a bexp = LESS ('a aexp) ('a aexp)
  5501             | AND ('a bexp) ('a bexp)
  5502             | OR ('a bexp) ('a bexp)
  5503 
  5504 as well as indirectly recursive datatypes such as
  5505 
  5506   datatype
  5507     ('a, 'b) term = Var 'a
  5508                   | App 'b ((('a, 'b) term) list)
  5509 
  5510 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5511 induction on mutually / indirectly recursive datatypes.
  5512 
  5513 Primrec equations are now stored in theory and can be accessed via
  5514 <function_name>.simps.
  5515 
  5516 INCOMPATIBILITIES:
  5517 
  5518   - Theories using datatypes must now have theory Datatype as an
  5519     ancestor.
  5520   - The specific <typename>.induct_tac no longer exists - use the
  5521     generic induct_tac instead.
  5522   - natE has been renamed to nat.exhaust - use exhaust_tac
  5523     instead of res_inst_tac ... natE. Note that the variable
  5524     names in nat.exhaust differ from the names in natE, this
  5525     may cause some "fragile" proofs to fail.
  5526   - The theorems split_<typename>_case and split_<typename>_case_asm
  5527     have been renamed to <typename>.split and <typename>.split_asm.
  5528   - Since default sorts of type variables are now handled correctly,
  5529     some datatype definitions may have to be annotated with explicit
  5530     sort constraints.
  5531   - Primrec definitions no longer require function name and type
  5532     of recursive argument.
  5533 
  5534 Consider using isatool fixdatatype to adapt your theories and proof
  5535 scripts to the new package (backup your sources first!).
  5536 
  5537 
  5538 * HOL/record package: considerably improved implementation; now
  5539 includes concrete syntax for record types, terms, updates; theorems
  5540 for surjective pairing and splitting !!-bound record variables; proof
  5541 support is as follows:
  5542 
  5543   1) standard conversions (selectors or updates applied to record
  5544 constructor terms) are part of the standard simpset;
  5545 
  5546   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5547 made part of standard simpset and claset via addIffs;
  5548 
  5549   3) a tactic for record field splitting (record_split_tac) is part of
  5550 the standard claset (addSWrapper);
  5551 
  5552 To get a better idea about these rules you may retrieve them via
  5553 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5554 the name of your record type.
  5555 
  5556 The split tactic 3) conceptually simplifies by the following rule:
  5557 
  5558   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5559 
  5560 Thus any record variable that is bound by meta-all will automatically
  5561 blow up into some record constructor term, consequently the
  5562 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5563 solve record problems automatically.
  5564 
  5565 
  5566 * reorganized the main HOL image: HOL/Integ and String loaded by
  5567 default; theory Main includes everything;
  5568 
  5569 * automatic simplification of integer sums and comparisons, using cancellation;
  5570 
  5571 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5572 
  5573 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5574 
  5575 * many new identities for unions, intersections, set difference, etc.;
  5576 
  5577 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5578 called split_if, split_split, split_sum_case and split_nat_case (to go
  5579 with add/delsplits);
  5580 
  5581 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5582 (?x::unit) = (); this is made part of the default simpset, which COULD
  5583 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5584 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5585 unit_abs_eta_conv is added in order to counter the effect of
  5586 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5587 %u.f();
  5588 
  5589 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5590 makes more sense);
  5591 
  5592 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5593   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5594   disjointness reasoning but breaking a few old proofs.
  5595 
  5596 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5597 to 'converse' from 'inverse' (for compatibility with ZF and some
  5598 literature);
  5599 
  5600 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5601 the well-founded relation;
  5602 
  5603 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5604     Compl A.  The "Compl" syntax remains available as input syntax for this
  5605     release ONLY.
  5606 
  5607 * HOL/Update: new theory of function updates:
  5608     f(a:=b) == %x. if x=a then b else f x
  5609 may also be iterated as in f(a:=b,c:=d,...);
  5610 
  5611 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5612 
  5613 * HOL/List:
  5614   - new function list_update written xs[i:=v] that updates the i-th
  5615     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5616   - new function `upt' written [i..j(] which generates the list
  5617     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5618     bound write [i..j], which is a shorthand for [i..j+1(].
  5619   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5620 
  5621 * HOL/Arith:
  5622   - removed 'pred' (predecessor) function;
  5623   - generalized some theorems about n-1;
  5624   - many new laws about "div" and "mod";
  5625   - new laws about greatest common divisors (see theory ex/Primes);
  5626 
  5627 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5628 instead of "inverse";
  5629 
  5630 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5631   of the multiset ordering;
  5632 
  5633 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5634   (not included by default);
  5635 
  5636 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5637 
  5638 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5639   programs, i.e. different program variables may have different types.
  5640 
  5641 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5642   [previously, this check worked only if the rewrite rule was unconditional]
  5643   Now rew can involve either definitions or equalities (either == or =).
  5644 
  5645 
  5646 *** ZF ***
  5647 
  5648 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5649   only the theorems proved on ZF.ML;
  5650 
  5651 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5652   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5653   disjointness reasoning but breaking a few old proofs.
  5654 
  5655 * ZF/Update: new theory of function updates
  5656     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5657   may also be iterated as in f(a:=b,c:=d,...);
  5658 
  5659 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5660 
  5661 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5662   [previously, this check worked only if the rewrite rule was unconditional]
  5663   Now rew can involve either definitions or equalities (either == or =).
  5664 
  5665 * case_tac provided for compatibility with HOL
  5666     (like the old excluded_middle_tac, but with subgoals swapped)
  5667 
  5668 
  5669 *** Internal programming interfaces ***
  5670 
  5671 * Pure: several new basic modules made available for general use, see
  5672 also src/Pure/README;
  5673 
  5674 * improved the theory data mechanism to support encapsulation (data
  5675 kind name replaced by private Object.kind, acting as authorization
  5676 key); new type-safe user interface via functor TheoryDataFun; generic
  5677 print_data function becomes basically useless;
  5678 
  5679 * removed global_names compatibility flag -- all theory declarations
  5680 are qualified by default;
  5681 
  5682 * module Pure/Syntax now offers quote / antiquote translation
  5683 functions (useful for Hoare logic etc. with implicit dependencies);
  5684 see HOL/ex/Antiquote for an example use;
  5685 
  5686 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5687 cterm -> thm;
  5688 
  5689 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5690 subgoal;
  5691 
  5692 * Display.print_goals function moved to Locale.print_goals;
  5693 
  5694 * standard print function for goals supports current_goals_markers
  5695 variable for marking begin of proof, end of proof, start of goal; the
  5696 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5697 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5698 for example;
  5699 
  5700 
  5701 
  5702 New in Isabelle98 (January 1998)
  5703 --------------------------------
  5704 
  5705 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5706 
  5707 * changed lexical syntax of terms / types: dots made part of long
  5708 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5709 
  5710 * simpset (and claset) reference variable replaced by functions
  5711 simpset / simpset_ref;
  5712 
  5713 * no longer supports theory aliases (via merge) and non-trivial
  5714 implicit merge of thms' signatures;
  5715 
  5716 * most internal names of constants changed due to qualified names;
  5717 
  5718 * changed Pure/Sequence interface (see Pure/seq.ML);
  5719 
  5720 
  5721 *** General Changes ***
  5722 
  5723 * hierachically structured name spaces (for consts, types, axms, thms
  5724 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5725 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5726 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5727 long_names for fully qualified output names; NOTE: ML programs
  5728 (special tactics, packages etc.) referring to internal names may have
  5729 to be adapted to cope with fully qualified names; in case of severe
  5730 backward campatibility problems try setting 'global_names' at compile
  5731 time to have enrything declared within a flat name space; one may also
  5732 fine tune name declarations in theories via the 'global' and 'local'
  5733 section;
  5734 
  5735 * reimplemented the implicit simpset and claset using the new anytype
  5736 data filed in signatures; references simpset:simpset ref etc. are
  5737 replaced by functions simpset:unit->simpset and
  5738 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5739 to patch your ML files accordingly;
  5740 
  5741 * HTML output now includes theory graph data for display with Java
  5742 applet or isatool browser; data generated automatically via isatool
  5743 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5744 
  5745 * defs may now be conditional; improved rewrite_goals_tac to handle
  5746 conditional equations;
  5747 
  5748 * defs now admits additional type arguments, using TYPE('a) syntax;
  5749 
  5750 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5751 creates a new theory node; implicit merge of thms' signatures is
  5752 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5753 transfer:theory->thm->thm in (rare) cases;
  5754 
  5755 * improved handling of draft signatures / theories; draft thms (and
  5756 ctyps, cterms) are automatically promoted to real ones;
  5757 
  5758 * slightly changed interfaces for oracles: admit many per theory, named
  5759 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5760 
  5761 * print_goals: optional output of const types (set show_consts and
  5762 show_types);
  5763 
  5764 * improved output of warnings (###) and errors (***);
  5765 
  5766 * subgoal_tac displays a warning if the new subgoal has type variables;
  5767 
  5768 * removed old README and Makefiles;
  5769 
  5770 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5771 
  5772 * removed obsolete init_pps and init_database;
  5773 
  5774 * deleted the obsolete tactical STATE, which was declared by
  5775     fun STATE tacfun st = tacfun st st;
  5776 
  5777 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5778 (which abbreviates $HOME);
  5779 
  5780 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5781 use isatool fixseq to adapt your ML programs (this works for fully
  5782 qualified references to the Sequence structure only!);
  5783 
  5784 * use_thy no longer requires writable current directory; it always
  5785 reloads .ML *and* .thy file, if either one is out of date;
  5786 
  5787 
  5788 *** Classical Reasoner ***
  5789 
  5790 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5791 tactics that use classical reasoning to simplify a subgoal without
  5792 splitting it into several subgoals;
  5793 
  5794 * Safe_tac: like safe_tac but uses the default claset;
  5795 
  5796 
  5797 *** Simplifier ***
  5798 
  5799 * added simplification meta rules:
  5800     (asm_)(full_)simplify: simpset -> thm -> thm;
  5801 
  5802 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5803 logics (again);
  5804 
  5805 * added prems argument to simplification procedures;
  5806 
  5807 * HOL, FOL, ZF: added infix function `addsplits':
  5808   instead of `<simpset> setloop (split_tac <thms>)'
  5809   you can simply write `<simpset> addsplits <thms>'
  5810 
  5811 
  5812 *** Syntax ***
  5813 
  5814 * TYPE('a) syntax for type reflection terms;
  5815 
  5816 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5817 
  5818 * pretty printer: changed order of mixfix annotation preference (again!);
  5819 
  5820 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5821 
  5822 
  5823 *** HOL ***
  5824 
  5825 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5826   with `addloop' of the simplifier to faciliate case splitting in premises.
  5827 
  5828 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5829 
  5830 * HOL/Auth: new protocol proofs including some for the Internet
  5831   protocol TLS;
  5832 
  5833 * HOL/Map: new theory of `maps' a la VDM;
  5834 
  5835 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5836 cancelling out common nat summands from =, <, <= (in)equalities, or
  5837 differences; simplification procedures nat_cancel_factor for
  5838 cancelling common factor from =, <, <= (in)equalities over natural
  5839 sums; nat_cancel contains both kinds of procedures, it is installed by
  5840 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5841 
  5842 * HOL/simplifier: terms of the form
  5843   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5844   are rewritten to
  5845   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5846   and those of the form
  5847   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5848   are rewritten to
  5849   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5850 
  5851 * HOL/datatype
  5852   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5853 
  5854   P(t_case f1 ... fn x) =
  5855      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5856         ...
  5857        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5858      )
  5859 
  5860   and a theorem `split_t_case_asm' of the form
  5861 
  5862   P(t_case f1 ... fn x) =
  5863     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5864         ...
  5865        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5866      )
  5867   which can be added to a simpset via `addsplits'. The existing theorems
  5868   expand_list_case and expand_option_case have been renamed to
  5869   split_list_case and split_option_case.
  5870 
  5871 * HOL/Arithmetic:
  5872   - `pred n' is automatically converted to `n-1'.
  5873     Users are strongly encouraged not to use `pred' any longer,
  5874     because it will disappear altogether at some point.
  5875   - Users are strongly encouraged to write "0 < n" rather than
  5876     "n ~= 0". Theorems and proof tools have been modified towards this
  5877     `standard'.
  5878 
  5879 * HOL/Lists:
  5880   the function "set_of_list" has been renamed "set" (and its theorems too);
  5881   the function "nth" now takes its arguments in the reverse order and
  5882   has acquired the infix notation "!" as in "xs!n".
  5883 
  5884 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5885 
  5886 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5887   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5888 
  5889 * HOL/record: extensible records with schematic structural subtyping
  5890 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5891 still lacks various theorems and concrete record syntax;
  5892 
  5893 
  5894 *** HOLCF ***
  5895 
  5896 * removed "axioms" and "generated by" sections;
  5897 
  5898 * replaced "ops" section by extended "consts" section, which is capable of
  5899   handling the continuous function space "->" directly;
  5900 
  5901 * domain package:
  5902   . proves theorems immediately and stores them in the theory,
  5903   . creates hierachical name space,
  5904   . now uses normal mixfix annotations (instead of cinfix...),
  5905   . minor changes to some names and values (for consistency),
  5906   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5907   . separator between mutual domain defs: changed "," to "and",
  5908   . improved handling of sort constraints;  now they have to
  5909     appear on the left-hand side of the equations only;
  5910 
  5911 * fixed LAM <x,y,zs>.b syntax;
  5912 
  5913 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5914 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5915 
  5916 
  5917 *** FOL and ZF ***
  5918 
  5919 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5920   with `addloop' of the simplifier to faciliate case splitting in premises.
  5921 
  5922 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5923 in HOL, they strip ALL and --> from proved theorems;
  5924 
  5925 
  5926 
  5927 New in Isabelle94-8 (May 1997)
  5928 ------------------------------
  5929 
  5930 *** General Changes ***
  5931 
  5932 * new utilities to build / run / maintain Isabelle etc. (in parts
  5933 still somewhat experimental); old Makefiles etc. still functional;
  5934 
  5935 * new 'Isabelle System Manual';
  5936 
  5937 * INSTALL text, together with ./configure and ./build scripts;
  5938 
  5939 * reimplemented type inference for greater efficiency, better error
  5940 messages and clean internal interface;
  5941 
  5942 * prlim command for dealing with lots of subgoals (an easier way of
  5943 setting goals_limit);
  5944 
  5945 
  5946 *** Syntax ***
  5947 
  5948 * supports alternative (named) syntax tables (parser and pretty
  5949 printer); internal interface is provided by add_modesyntax(_i);
  5950 
  5951 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5952 be used in conjunction with the Isabelle symbol font; uses the
  5953 "symbols" syntax table;
  5954 
  5955 * added token_translation interface (may translate name tokens in
  5956 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5957 the current print_mode); IMPORTANT: user print translation functions
  5958 are responsible for marking newly introduced bounds
  5959 (Syntax.mark_boundT);
  5960 
  5961 * token translations for modes "xterm" and "xterm_color" that display
  5962 names in bold, underline etc. or colors (which requires a color
  5963 version of xterm);
  5964 
  5965 * infixes may now be declared with names independent of their syntax;
  5966 
  5967 * added typed_print_translation (like print_translation, but may
  5968 access type of constant);
  5969 
  5970 
  5971 *** Classical Reasoner ***
  5972 
  5973 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5974 some limitations.  Blast_tac...
  5975   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5976   + ignores elimination rules that don't have the correct format
  5977         (the conclusion MUST be a formula variable)
  5978   + ignores types, which can make HOL proofs fail
  5979   + rules must not require higher-order unification, e.g. apply_type in ZF
  5980     [message "Function Var's argument not a bound variable" relates to this]
  5981   + its proof strategy is more general but can actually be slower
  5982 
  5983 * substitution with equality assumptions no longer permutes other
  5984 assumptions;
  5985 
  5986 * minor changes in semantics of addafter (now called addaltern); renamed
  5987 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5988 (and access functions for it);
  5989 
  5990 * improved combination of classical reasoner and simplifier:
  5991   + functions for handling clasimpsets
  5992   + improvement of addss: now the simplifier is called _after_ the
  5993     safe steps.
  5994   + safe variant of addss called addSss: uses safe simplifications
  5995     _during_ the safe steps. It is more complete as it allows multiple
  5996     instantiations of unknowns (e.g. with slow_tac).
  5997 
  5998 *** Simplifier ***
  5999 
  6000 * added interface for simplification procedures (functions that
  6001 produce *proven* rewrite rules on the fly, depending on current
  6002 redex);
  6003 
  6004 * ordering on terms as parameter (used for ordered rewriting);
  6005 
  6006 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6007 
  6008 * the solver is now split into a safe and an unsafe part.
  6009 This should be invisible for the normal user, except that the
  6010 functions setsolver and addsolver have been renamed to setSolver and
  6011 addSolver; added safe_asm_full_simp_tac;
  6012 
  6013 
  6014 *** HOL ***
  6015 
  6016 * a generic induction tactic `induct_tac' which works for all datatypes and
  6017 also for type `nat';
  6018 
  6019 * a generic case distinction tactic `exhaust_tac' which works for all
  6020 datatypes and also for type `nat';
  6021 
  6022 * each datatype comes with a function `size';
  6023 
  6024 * patterns in case expressions allow tuple patterns as arguments to
  6025 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6026 
  6027 * primrec now also works with type nat;
  6028 
  6029 * recdef: a new declaration form, allows general recursive functions to be
  6030 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6031 
  6032 * the constant for negation has been renamed from "not" to "Not" to
  6033 harmonize with FOL, ZF, LK, etc.;
  6034 
  6035 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6036 infinite lists;
  6037 
  6038 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6039 
  6040 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6041 problems in commutative rings, using axiomatic type classes for + and *;
  6042 
  6043 * more examples in HOL/MiniML and HOL/Auth;
  6044 
  6045 * more default rewrite rules for quantifiers, union/intersection;
  6046 
  6047 * a new constant `arbitrary == @x.False';
  6048 
  6049 * HOLCF/IOA replaces old HOL/IOA;
  6050 
  6051 * HOLCF changes: derived all rules and arities
  6052   + axiomatic type classes instead of classes
  6053   + typedef instead of faking type definitions
  6054   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6055   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6056   + eliminated the types void, one, tr
  6057   + use unit lift and bool lift (with translations) instead of one and tr
  6058   + eliminated blift from Lift3.thy (use Def instead of blift)
  6059   all eliminated rules are derived as theorems --> no visible changes ;
  6060 
  6061 
  6062 *** ZF ***
  6063 
  6064 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6065 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6066 as ZF_cs addSIs [equalityI];
  6067 
  6068 
  6069 
  6070 New in Isabelle94-7 (November 96)
  6071 ---------------------------------
  6072 
  6073 * allowing negative levels (as offsets) in prlev and choplev;
  6074 
  6075 * super-linear speedup for large simplifications;
  6076 
  6077 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6078 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6079 FAIL); can suppress it using the command Delsimps (ex_simps @
  6080 all_simps); De Morgan laws are also now included, by default;
  6081 
  6082 * improved printing of ==>  :  ~:
  6083 
  6084 * new object-logic "Sequents" adds linear logic, while replacing LK
  6085 and Modal (thanks to Sara Kalvala);
  6086 
  6087 * HOL/Auth: correctness proofs for authentication protocols;
  6088 
  6089 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6090 examples on HOL/Auth);
  6091 
  6092 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6093 the rewriter and classical reasoner simultaneously;
  6094 
  6095 * function uresult no longer returns theorems in "standard" format;
  6096 regain previous version by: val uresult = standard o uresult;
  6097 
  6098 
  6099 
  6100 New in Isabelle94-6
  6101 -------------------
  6102 
  6103 * oracles -- these establish an interface between Isabelle and trusted
  6104 external reasoners, which may deliver results as theorems;
  6105 
  6106 * proof objects (in particular record all uses of oracles);
  6107 
  6108 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6109 
  6110 * "constdefs" section in theory files;
  6111 
  6112 * "primrec" section (HOL) no longer requires names;
  6113 
  6114 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6115 
  6116 
  6117 
  6118 New in Isabelle94-5
  6119 -------------------
  6120 
  6121 * reduced space requirements;
  6122 
  6123 * automatic HTML generation from theories;
  6124 
  6125 * theory files no longer require "..." (quotes) around most types;
  6126 
  6127 * new examples, including two proofs of the Church-Rosser theorem;
  6128 
  6129 * non-curried (1994) version of HOL is no longer distributed;
  6130 
  6131 
  6132 
  6133 New in Isabelle94-4
  6134 -------------------
  6135 
  6136 * greatly reduced space requirements;
  6137 
  6138 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6139 
  6140 * searchable theorem database (see the section "Retrieving theorems" on
  6141 page 8 of the Reference Manual);
  6142 
  6143 * new examples, including Grabczewski's monumental case study of the
  6144 Axiom of Choice;
  6145 
  6146 * The previous version of HOL renamed to Old_HOL;
  6147 
  6148 * The new version of HOL (previously called CHOL) uses a curried syntax
  6149 for functions.  Application looks like f a b instead of f(a,b);
  6150 
  6151 * Mutually recursive inductive definitions finally work in HOL;
  6152 
  6153 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6154 translates to the operator "split";
  6155 
  6156 
  6157 
  6158 New in Isabelle94-3
  6159 -------------------
  6160 
  6161 * new infix operator, addss, allowing the classical reasoner to
  6162 perform simplification at each step of its search.  Example:
  6163         fast_tac (cs addss ss)
  6164 
  6165 * a new logic, CHOL, the same as HOL, but with a curried syntax
  6166 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  6167 look like (a,b) instead of <a,b>;
  6168 
  6169 * PLEASE NOTE: CHOL will eventually replace HOL!
  6170 
  6171 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  6172 It translates to the operator "split".  A new theory of integers is available;
  6173 
  6174 * In ZF, integer numerals now denote two's-complement binary integers.
  6175 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  6176 
  6177 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  6178 of the Axiom of Choice;
  6179 
  6180 
  6181 
  6182 New in Isabelle94-2
  6183 -------------------
  6184 
  6185 * Significantly faster resolution;
  6186 
  6187 * the different sections in a .thy file can now be mixed and repeated
  6188 freely;
  6189 
  6190 * Database of theorems for FOL, HOL and ZF.  New
  6191 commands including qed, qed_goal and bind_thm store theorems in the database.
  6192 
  6193 * Simple database queries: return a named theorem (get_thm) or all theorems of
  6194 a given theory (thms_of), or find out what theory a theorem was proved in
  6195 (theory_of_thm);
  6196 
  6197 * Bugs fixed in the inductive definition and datatype packages;
  6198 
  6199 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  6200 and HOL_dup_cs obsolete;
  6201 
  6202 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  6203 have been removed;
  6204 
  6205 * Simpler definition of function space in ZF;
  6206 
  6207 * new results about cardinal and ordinal arithmetic in ZF;
  6208 
  6209 * 'subtype' facility in HOL for introducing new types as subsets of existing
  6210 types;
  6211 
  6212 :mode=text:wrap=hard:maxLineLen=72: