NEWS
author wenzelm
Fri Mar 20 17:12:37 2009 +0100 (2009-03-20)
changeset 30609 983e8b6e4e69
parent 30577 79cc595655c0
child 30706 e20227b5e6a3
permissions -rw-r--r--
Disposed old declarations, tactics, tactic combinators that refer to the simpset or claset of an implicit theory;
     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 classes "top" and "bot" with corresponding operations "top" and "bot"
   334 in theory Orderings;  instantiation of class "complete_lattice" requires
   335 instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   336 
   337 * Changed definition lemma "less_fun_def" in order to provide an instance
   338 for preorders on functions;  use lemma "less_le" instead.  INCOMPATIBILITY.
   339 
   340 * Unified theorem tables for both code code generators.  Thus
   341 [code func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   342 
   343 * Constants "undefined" and "default" replace "arbitrary".  Usually
   344 "undefined" is the right choice to replace "arbitrary", though logically
   345 there is no difference.  INCOMPATIBILITY.
   346 
   347 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   348 Posix processes.  Avoids potentially expensive forking of the ML
   349 process.  New thread-based implementation also works on non-Unix
   350 platforms (Cygwin).  Provers are no longer hardwired, but defined
   351 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   352 commands are covered in the isar-ref manual.
   353 
   354 * Wrapper scripts for remote SystemOnTPTP service allows to use
   355 sledgehammer without local ATP installation (Vampire etc.). Other
   356 provers may be included via suitable ML wrappers, see also
   357 src/HOL/ATP_Linkup.thy.
   358 
   359 * Normalization by evaluation now allows non-leftlinear equations.
   360 Declare with attribute [code nbe].
   361 
   362 * Command "value" now integrates different evaluation
   363 mechanisms.  The result of the first successful evaluation mechanism
   364 is printed.  In square brackets a particular named evaluation
   365 mechanisms may be specified (currently, [SML], [code] or [nbe]).  See
   366 further src/HOL/ex/Eval_Examples.thy.
   367 
   368 * New method "sizechange" to automate termination proofs using (a
   369 modification of) the size-change principle. Requires SAT solver. See
   370 src/HOL/ex/Termination.thy for examples.
   371 
   372 * HOL/Orderings: class "wellorder" moved here, with explicit induction
   373 rule "less_induct" as assumption.  For instantiation of "wellorder" by
   374 means of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.
   375 
   376 * HOL/Orderings: added class "preorder" as superclass of "order".
   377 INCOMPATIBILITY: Instantiation proofs for order, linorder
   378 etc. slightly changed.  Some theorems named order_class.* now named
   379 preorder_class.*.
   380 
   381 * HOL/Relation:
   382 Renamed "refl" to "refl_on", "reflexive" to "refl, "diag" to "Id_on".
   383 
   384 * HOL/Finite_Set: added a new fold combinator of type
   385   ('a => 'b => 'b) => 'b => 'a set => 'b
   386 Occasionally this is more convenient than the old fold combinator which is
   387 now defined in terms of the new one and renamed to fold_image.
   388 
   389 * HOL/Ring_and_Field and HOL/OrderedGroup: The lemmas "group_simps" and
   390 "ring_simps" have been replaced by "algebra_simps" (which can be extended with
   391 further lemmas!). At the moment both still exist but the former will disappear
   392 at some point.
   393 
   394 * HOL/Power: Lemma power_Suc is now declared as a simp rule in class
   395 recpower.  Type-specific simp rules for various recpower types have
   396 been removed.  INCOMPATIBILITY.  Rename old lemmas as follows:
   397 
   398 rat_power_0    -> power_0
   399 rat_power_Suc  -> power_Suc
   400 realpow_0      -> power_0
   401 realpow_Suc    -> power_Suc
   402 complexpow_0   -> power_0
   403 complexpow_Suc -> power_Suc
   404 power_poly_0   -> power_0
   405 power_poly_Suc -> power_Suc
   406 
   407 * HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
   408 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   409 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   410 of lemmas from Divides has been generalized from nat to class
   411 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   412 renames resulting from duplicate elimination:
   413 
   414     dvd_def_mod ~>          dvd_eq_mod_eq_0
   415     zero_dvd_iff ~>         dvd_0_left_iff
   416     dvd_0 ~>                dvd_0_right
   417     DIVISION_BY_ZERO_DIV ~> div_by_0
   418     DIVISION_BY_ZERO_MOD ~> mod_by_0
   419     mult_div ~>             div_mult_self2_is_id
   420     mult_mod ~>             mod_mult_self2_is_0
   421 
   422 * HOL/IntDiv: removed many lemmas that are instances of class-based
   423 generalizations (from Divides and Ring_and_Field).
   424 INCOMPATIBILITY. Rename old lemmas as follows:
   425 
   426 dvd_diff               -> nat_dvd_diff
   427 dvd_zminus_iff         -> dvd_minus_iff
   428 mod_add1_eq            -> mod_add_eq
   429 mod_mult1_eq           -> mod_mult_right_eq
   430 mod_mult1_eq'          -> mod_mult_left_eq
   431 mod_mult_distrib_mod   -> mod_mult_eq
   432 nat_mod_add_left_eq    -> mod_add_left_eq
   433 nat_mod_add_right_eq   -> mod_add_right_eq
   434 nat_mod_div_trivial    -> mod_div_trivial
   435 nat_mod_mod_trivial    -> mod_mod_trivial
   436 zdiv_zadd_self1        -> div_add_self1
   437 zdiv_zadd_self2        -> div_add_self2
   438 zdiv_zmult_self1       -> div_mult_self2_is_id
   439 zdiv_zmult_self2       -> div_mult_self1_is_id
   440 zdvd_triv_left         -> dvd_triv_left
   441 zdvd_triv_right        -> dvd_triv_right
   442 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   443 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   444 zmod_zadd_left_eq      -> mod_add_left_eq
   445 zmod_zadd_right_eq     -> mod_add_right_eq
   446 zmod_zadd_self1        -> mod_add_self1
   447 zmod_zadd_self2        -> mod_add_self2
   448 zmod_zadd1_eq          -> mod_add_eq
   449 zmod_zdiff1_eq         -> mod_diff_eq
   450 zmod_zdvd_zmod         -> mod_mod_cancel
   451 zmod_zmod_cancel       -> mod_mod_cancel
   452 zmod_zmult_self1       -> mod_mult_self2_is_0
   453 zmod_zmult_self2       -> mod_mult_self1_is_0
   454 zmod_1                 -> mod_by_1
   455 zdiv_1                 -> div_by_1
   456 zdvd_abs1              -> abs_dvd_iff
   457 zdvd_abs2              -> dvd_abs_iff
   458 zdvd_refl              -> dvd_refl
   459 zdvd_trans             -> dvd_trans
   460 zdvd_zadd              -> dvd_add
   461 zdvd_zdiff             -> dvd_diff
   462 zdvd_zminus_iff        -> dvd_minus_iff
   463 zdvd_zminus2_iff       -> minus_dvd_iff
   464 zdvd_zmultD            -> dvd_mult_right
   465 zdvd_zmultD2           -> dvd_mult_left
   466 zdvd_zmult_mono        -> mult_dvd_mono
   467 zdvd_0_right           -> dvd_0_right
   468 zdvd_0_left            -> dvd_0_left_iff
   469 zdvd_1_left            -> one_dvd
   470 zminus_dvd_iff         -> minus_dvd_iff
   471 
   472 * HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   473 zlcm (for int); carried together from various gcd/lcm developements in
   474 the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
   475 corresponding theorems renamed accordingly.  INCOMPATIBILITY.  To
   476 recover tupled syntax, use syntax declarations like:
   477 
   478     hide (open) const gcd
   479     abbreviation gcd where
   480       "gcd == (%(a, b). GCD.gcd a b)"
   481     notation (output)
   482       GCD.gcd ("gcd '(_, _')")
   483 
   484 (analogously for lcm, zgcd, zlcm).
   485 
   486 * HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   487 
   488 * The real numbers offer decimal input syntax: 12.34 is translated into
   489   1234/10^2. This translation is not reversed upon output.
   490 
   491 * New ML antiquotation @{code}: takes constant as argument, generates
   492 corresponding code in background and inserts name of the corresponding
   493 resulting ML value/function/datatype constructor binding in place.
   494 All occurrences of @{code} with a single ML block are generated
   495 simultaneously.  Provides a generic and safe interface for
   496 instrumentalizing code generation.  See HOL/ex/Code_Antiq for a toy
   497 example, or HOL/Complex/ex/ReflectedFerrack for a more ambitious
   498 application.  In future you ought refrain from ad-hoc compiling
   499 generated SML code on the ML toplevel.  Note that (for technical
   500 reasons) @{code} cannot refer to constants for which user-defined
   501 serializations are set.  Refer to the corresponding ML counterpart
   502 directly in that cases.
   503 
   504 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   505 Complex_Main.thy remain as they are.
   506 
   507 * New image HOL-Plain provides a minimal HOL with the most important
   508 tools available (inductive, datatype, primrec, ...).  By convention
   509 the corresponding theory Plain should be ancestor of every further
   510 (library) theory.  Some library theories now have ancestor Plain
   511 (instead of Main), thus theory Main occasionally has to be imported
   512 explicitly.
   513 
   514 * The metis method now fails in the usual manner, rather than raising
   515 an exception, if it determines that it cannot prove the theorem.
   516 
   517 * The metis method no longer fails because the theorem is too trivial
   518 (contains the empty clause).
   519 
   520 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   521 as the structured Isar versions "cases" and "induct", cf. the
   522 corresponding "cases" and "induct" attributes.  Mutual induction rules
   523 are now presented as a list of individual projections
   524 (e.g. foo_bar.inducts for types foo and bar); the old format with
   525 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   526 rare situations a different rule is selected --- notably nested tuple
   527 elimination instead of former prod.exhaust: use explicit (case_tac t
   528 rule: prod.exhaust) here.
   529 
   530 * Attributes "cases", "induct", "coinduct" support "del" option.
   531 
   532 * Removed fact "case_split_thm", which duplicates "case_split".
   533 
   534 * Command 'rep_datatype': instead of theorem names the command now
   535 takes a list of terms denoting the constructors of the type to be
   536 represented as datatype.  The characteristic theorems have to be
   537 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   538 have disappeared in favour of existing ones:
   539 
   540     unit_induct                 ~> unit.induct
   541     prod_induct                 ~> prod.induct
   542     sum_induct                  ~> sum.induct
   543     Suc_Suc_eq                  ~> nat.inject
   544     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   545 
   546 * The option datatype has been moved to a new theory HOL/Option.thy.
   547 Renamed option_map to Option.map, and o2s to Option.set.
   548 
   549 * Library/Nat_Infinity: added addition, numeral syntax and more
   550 instantiations for algebraic structures.  Removed some duplicate
   551 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   552 
   553 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   554 menu.
   555 
   556 * Linear arithmetic now ignores all inequalities when
   557 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   558 
   559 
   560 *** HOL-Algebra ***
   561 
   562 * New locales for orders and lattices where the equivalence relation
   563 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   564 locales use a record structure with field eq for the equivalence.
   565 
   566 * New theory of factorial domains.
   567 
   568 * Units_l_inv and Units_r_inv are now simprules by default.
   569 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   570 and/or r_inv will now also require deletion of these lemmas.
   571 
   572 * Renamed the following theorems.  INCOMPATIBILITY.
   573 UpperD ~> Upper_memD
   574 LowerD ~> Lower_memD
   575 least_carrier ~> least_closed
   576 greatest_carrier ~> greatest_closed
   577 greatest_Lower_above ~> greatest_Lower_below
   578 one_zero ~> carrier_one_zero
   579 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   580 
   581 
   582 *** HOL-NSA ***
   583 
   584 * Created new image HOL-NSA, containing theories of nonstandard
   585 analysis which were previously part of HOL-Complex.  Entry point
   586 Hyperreal.thy remains valid, but theories formerly using
   587 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   588 
   589 
   590 *** ZF ***
   591 
   592 * Proof of Zorn's Lemma for partial orders.
   593 
   594 
   595 *** HOLCF ***
   596 
   597 * Reimplemented the simplification procedure for proving continuity
   598 subgoals.  The new simproc is extensible; users can declare additional
   599 continuity introduction rules with the attribute [cont2cont].
   600 
   601 * The continuity simproc now uses a different introduction rule for
   602 solving continuity subgoals on terms with lambda abstractions.  In
   603 some rare cases the new simproc may fail to solve subgoals that the
   604 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   605 Potential INCOMPATIBILITY.
   606 
   607 * The syntax of the fixrec package has changed.  The specification
   608 syntax now conforms in style to definition, primrec, function, etc.
   609 See HOLCF/ex/Fixrec_ex.thy for examples.  INCOMPATIBILITY.
   610 
   611 
   612 *** ML ***
   613 
   614 * High-level support for concurrent ML programming, see
   615 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   616 particularly convenient to organize independent functional
   617 computations.  The concept of "synchronized variables" provides a
   618 higher-order interface for components with shared state, avoiding the
   619 delicate details of mutexes and condition variables.  [Poly/ML 5.2.1
   620 or later]
   621 
   622 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   623 and Method.setup, as well as commands 'attribute_setup' and
   624 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   625 existing code accordingly, or use plain 'setup' together with old
   626 Method.add_method.
   627 
   628 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   629 to 'a -> thm, while results are always tagged with an authentic oracle
   630 name.  The Isar command 'oracle' is now polymorphic, no argument type
   631 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   632 accordingly.  Note that extra performance may be gained by producing
   633 the cterm carefully, avoiding slow Thm.cterm_of.
   634 
   635 * ML bindings produced via Isar commands are stored within the Isar
   636 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   637 become thread-safe and work with undo as expected (concerning
   638 top-level bindings, not side-effects on global references).
   639 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   640 compiler at runtime; really global bindings need to be given outside a
   641 theory. [Poly/ML 5.2 or later]
   642 
   643 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   644 context. Top-level ML bindings are stored within the proof context in
   645 a purely sequential fashion, disregarding the nested proof structure.
   646 ML bindings introduced by 'ML_prf' are discarded at the end of the
   647 proof.  [Poly/ML 5.2 or later]
   648 
   649 * Generic Toplevel.add_hook interface allows to analyze the result of
   650 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   651 for theorem dependency output of transactions resulting in a new
   652 theory state.
   653 
   654 * More systematic treatment of long names, abstract name bindings, and
   655 name space operations.  Basic operations on qualified names have been
   656 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   657 Long_Name.append.  Old type bstring has been mostly replaced by
   658 abstract type binding (see structure Binding), which supports precise
   659 qualification (by packages and local theory targets), as well as
   660 proper tracking of source positions.  INCOMPATIBILITY, need to wrap
   661 old bstring values into Binding.name, or better pass through abstract
   662 bindings everywhere.  See further src/Pure/General/long_name.ML,
   663 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   664 
   665 * Simplified interface for defining document antiquotations via
   666 ThyOutput.antiquotation, ThyOutput.output, and optionally
   667 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   668 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   669 examples.
   670 
   671 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   672 LocalTheory.note etc.) now refer to the *full* internal name, not the
   673 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   674 
   675 * Rules and tactics that read instantiations (read_instantiate,
   676 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   677 context, which is required for parsing and type-checking.  Moreover,
   678 the variables are specified as plain indexnames, not string encodings
   679 thereof.  INCOMPATIBILITY.
   680 
   681 * Disposed old type and term read functions (Sign.read_def_typ,
   682 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   683 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   684 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   685 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   686 resort for legacy applications.
   687 
   688 * Disposed old declarations, tactics, tactic combinators that refer to
   689 the simpset or claset of an implicit theory (such as Addsimps,
   690 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   691 embedded ML text, or local_simpset_of with a proper context passed as
   692 explicit runtime argument.
   693 
   694 * Antiquotations: block-structured compilation context indicated by
   695 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   696 
   697   @{let ?pat = term}                      - term abbreviation (HO matching)
   698   @{note name = fact}                     - fact abbreviation
   699   @{thm fact}                             - singleton fact (with attributes)
   700   @{thms fact}                            - general fact (with attributes)
   701   @{lemma prop by method}                 - singleton goal
   702   @{lemma prop by meth1 meth2}            - singleton goal
   703   @{lemma prop1 ... propN by method}      - general goal
   704   @{lemma prop1 ... propN by meth1 meth2} - general goal
   705   @{lemma (open) ...}                     - open derivation
   706 
   707 
   708 *** System ***
   709 
   710 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   711 Poly/ML 5.2.1 or later.
   712 
   713 * The Isabelle "emacs" tool provides a specific interface to invoke
   714 Proof General / Emacs, with more explicit failure if that is not
   715 installed (the old isabelle-interface script silently falls back on
   716 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   717 installation location of the Proof General distribution.
   718 
   719 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   720 the Isabelle process into a JVM/Scala application.  See
   721 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   722 process wrapper has been discontinued.)
   723 
   724 * Status messages (with exact source position information) are
   725 emitted, if proper markup print mode is enabled.  This allows
   726 user-interface components to provide detailed feedback on internal
   727 prover operations.
   728 
   729 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   730 
   731 
   732 
   733 New in Isabelle2008 (June 2008)
   734 -------------------------------
   735 
   736 *** General ***
   737 
   738 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   739 and updated, with formally checked references as hyperlinks.
   740 
   741 * Theory loader: use_thy (and similar operations) no longer set the
   742 implicit ML context, which was occasionally hard to predict and in
   743 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   744 provides a proper context already.
   745 
   746 * Theory loader: old-style ML proof scripts being *attached* to a thy
   747 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   748 'use' within a theory file will do the job.
   749 
   750 * Name space merge now observes canonical order, i.e. the second space
   751 is inserted into the first one, while existing entries in the first
   752 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   753 swap theory imports.
   754 
   755 * Syntax: symbol \<chi> is now considered a letter.  Potential
   756 INCOMPATIBILITY in identifier syntax etc.
   757 
   758 * Outer syntax: string tokens no longer admit escaped white space,
   759 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   760 white space without escapes.
   761 
   762 * Outer syntax: string tokens may contain arbitrary character codes
   763 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   764 "foo_bar".
   765 
   766 
   767 *** Pure ***
   768 
   769 * Context-dependent token translations.  Default setup reverts locally
   770 fixed variables, and adds hilite markup for undeclared frees.
   771 
   772 * Unused theorems can be found using the new command 'unused_thms'.
   773 There are three ways of invoking it:
   774 
   775 (1) unused_thms
   776      Only finds unused theorems in the current theory.
   777 
   778 (2) unused_thms thy_1 ... thy_n -
   779      Finds unused theorems in the current theory and all of its ancestors,
   780      excluding the theories thy_1 ... thy_n and all of their ancestors.
   781 
   782 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   783      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   784      their ancestors, excluding the theories thy_1 ... thy_n and all of
   785      their ancestors.
   786 
   787 In order to increase the readability of the list produced by
   788 unused_thms, theorems that have been created by a particular instance
   789 of a theory command such as 'inductive' or 'function' are considered
   790 to belong to the same "group", meaning that if at least one theorem in
   791 this group is used, the other theorems in the same group are no longer
   792 reported as unused.  Moreover, if all theorems in the group are
   793 unused, only one theorem in the group is displayed.
   794 
   795 Note that proof objects have to be switched on in order for
   796 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   797 usually the case when using Proof General with the default settings).
   798 
   799 * Authentic naming of facts disallows ad-hoc overwriting of previous
   800 theorems within the same name space.  INCOMPATIBILITY, need to remove
   801 duplicate fact bindings, or even accidental fact duplications.  Note
   802 that tools may maintain dynamically scoped facts systematically, using
   803 PureThy.add_thms_dynamic.
   804 
   805 * Command 'hide' now allows to hide from "fact" name space as well.
   806 
   807 * Eliminated destructive theorem database, simpset, claset, and
   808 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   809 update of theories within ML code.
   810 
   811 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   812 INCOMPATIBILITY, object-logics depending on former Pure require
   813 additional setup PureThy.old_appl_syntax_setup; object-logics
   814 depending on former CPure need to refer to Pure.
   815 
   816 * Commands 'use' and 'ML' are now purely functional, operating on
   817 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   818 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   819 INCOMPATIBILITY.
   820 
   821 * Command 'setup': discontinued implicit version with ML reference.
   822 
   823 * Instantiation target allows for simultaneous specification of class
   824 instance operations together with an instantiation proof.
   825 Type-checking phase allows to refer to class operations uniformly.
   826 See src/HOL/Complex/Complex.thy for an Isar example and
   827 src/HOL/Library/Eval.thy for an ML example.
   828 
   829 * Indexing of literal facts: be more serious about including only
   830 facts from the visible specification/proof context, but not the
   831 background context (locale etc.).  Affects `prop` notation and method
   832 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   833 situations.
   834 
   835 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   836 "(open)" option, which used to expose internal bound variables to the
   837 proof text.
   838 
   839 * Isar statements: removed obsolete case "rule_context".
   840 INCOMPATIBILITY, better use explicit fixes/assumes.
   841 
   842 * Locale proofs: default proof step now includes 'unfold_locales';
   843 hence 'proof' without argument may be used to unfold locale
   844 predicates.
   845 
   846 
   847 *** Document preparation ***
   848 
   849 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   850 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   851 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   852 spot); renamed link color from "darkblue" to "linkcolor" (default
   853 value unchanged, can be redefined via \definecolor); no longer sets
   854 "a4paper" option (unnecessary or even intrusive).
   855 
   856 * Antiquotation @{lemma A method} proves proposition A by the given
   857 method (either a method name or a method name plus (optional) method
   858 arguments in parentheses) and prints A just like @{prop A}.
   859 
   860 
   861 *** HOL ***
   862 
   863 * New primrec package.  Specification syntax conforms in style to
   864 definition/function/....  No separate induction rule is provided.  The
   865 "primrec" command distinguishes old-style and new-style specifications
   866 by syntax.  The former primrec package is now named OldPrimrecPackage.
   867 When adjusting theories, beware: constants stemming from new-style
   868 primrec specifications have authentic syntax.
   869 
   870 * Metis prover is now an order of magnitude faster, and also works
   871 with multithreading.
   872 
   873 * Metis: the maximum number of clauses that can be produced from a
   874 theorem is now given by the attribute max_clauses.  Theorems that
   875 exceed this number are ignored, with a warning printed.
   876 
   877 * Sledgehammer no longer produces structured proofs by default. To
   878 enable, declare [[sledgehammer_full = true]].  Attributes
   879 reconstruction_modulus, reconstruction_sorts renamed
   880 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   881 
   882 * Method "induct_scheme" derives user-specified induction rules
   883 from well-founded induction and completeness of patterns. This factors
   884 out some operations that are done internally by the function package
   885 and makes them available separately.  See
   886 src/HOL/ex/Induction_Scheme.thy for examples.
   887 
   888 * More flexible generation of measure functions for termination
   889 proofs: Measure functions can be declared by proving a rule of the
   890 form "is_measure f" and giving it the [measure_function] attribute.
   891 The "is_measure" predicate is logically meaningless (always true), and
   892 just guides the heuristic.  To find suitable measure functions, the
   893 termination prover sets up the goal "is_measure ?f" of the appropriate
   894 type and generates all solutions by prolog-style backwards proof using
   895 the declared rules.
   896 
   897 This setup also deals with rules like 
   898 
   899   "is_measure f ==> is_measure (list_size f)"
   900 
   901 which accommodates nested datatypes that recurse through lists.
   902 Similar rules are predeclared for products and option types.
   903 
   904 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   905 
   906   INCOMPATIBILITIES:
   907 
   908   - Definitions of overloaded constants on sets have to be replaced by
   909     definitions on => and bool.
   910 
   911   - Some definitions of overloaded operators on sets can now be proved
   912     using the definitions of the operators on => and bool.  Therefore,
   913     the following theorems have been renamed:
   914 
   915       subset_def   -> subset_eq
   916       psubset_def  -> psubset_eq
   917       set_diff_def -> set_diff_eq
   918       Compl_def    -> Compl_eq
   919       Sup_set_def  -> Sup_set_eq
   920       Inf_set_def  -> Inf_set_eq
   921       sup_set_def  -> sup_set_eq
   922       inf_set_def  -> inf_set_eq
   923 
   924   - Due to the incompleteness of the HO unification algorithm, some
   925     rules such as subst may require manual instantiation, if some of
   926     the unknowns in the rule is a set.
   927 
   928   - Higher order unification and forward proofs:
   929     The proof pattern
   930 
   931       have "P (S::'a set)" <...>
   932       then have "EX S. P S" ..
   933 
   934     no longer works (due to the incompleteness of the HO unification
   935     algorithm) and must be replaced by the pattern
   936 
   937       have "EX S. P S"
   938       proof
   939         show "P S" <...>
   940       qed
   941 
   942   - Calculational reasoning with subst (or similar rules):
   943     The proof pattern
   944 
   945       have "P (S::'a set)" <...>
   946       also have "S = T" <...>
   947       finally have "P T" .
   948 
   949     no longer works (for similar reasons as the previous example) and
   950     must be replaced by something like
   951 
   952       have "P (S::'a set)" <...>
   953       moreover have "S = T" <...>
   954       ultimately have "P T" by simp
   955 
   956   - Tactics or packages written in ML code:
   957     Code performing pattern matching on types via
   958 
   959       Type ("set", [T]) => ...
   960 
   961     must be rewritten. Moreover, functions like strip_type or
   962     binder_types no longer return the right value when applied to a
   963     type of the form
   964 
   965       T1 => ... => Tn => U => bool
   966 
   967     rather than
   968 
   969       T1 => ... => Tn => U set
   970 
   971 * Merged theories Wellfounded_Recursion, Accessible_Part and
   972 Wellfounded_Relations to theory Wellfounded.
   973 
   974 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   975 
   976 * Class finite no longer treats UNIV as class parameter.  Use class
   977 enum from theory Library/Enum instead to achieve a similar effect.
   978 INCOMPATIBILITY.
   979 
   980 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   981 and "Cons".  INCOMPATIBILITY.
   982 
   983 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   984 Potential INCOMPATIBILITY.
   985 
   986 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   987 injective_fst_snd removed, use split_eta and prod_eqI instead.
   988 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   989 
   990 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   991 the same name in theory Orderings:
   992 
   993   less_trans
   994   less_linear
   995   le_imp_less_or_eq
   996   le_less_trans
   997   less_le_trans
   998   less_not_sym
   999   less_asym
  1000 
  1001 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1002 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1003 and different variable names.
  1004 
  1005 * Library/Option_ord.thy: Canonical order on option type.
  1006 
  1007 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1008 finite maps.
  1009 
  1010 * Library/Countable.thy: Type class for countable types.
  1011 
  1012 * Theory Int: The representation of numerals has changed.  The infix
  1013 operator BIT and the bit datatype with constructors B0 and B1 have
  1014 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1015 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1016 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1017 accordingly.
  1018 
  1019 * Theory Nat: definition of <= and < on natural numbers no longer
  1020 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1021 le_def and less_def have disappeared.  Consider lemmas not_less
  1022 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1023 
  1024 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1025 (whose purpose mainly is for various fold_set functionals) have been
  1026 abandoned in favor of the existing algebraic classes
  1027 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1028 lower_semilattice (resp. upper_semilattice) and linorder.
  1029 INCOMPATIBILITY.
  1030 
  1031 * Theory Transitive_Closure: induct and cases rules now declare proper
  1032 case_names ("base" and "step").  INCOMPATIBILITY.
  1033 
  1034 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1035 lattices.  The form set-specific version is available as
  1036 Inductive.lfp_ordinal_induct_set.
  1037 
  1038 * Renamed theorems "power.simps" to "power_int.simps".
  1039 INCOMPATIBILITY.
  1040 
  1041 * Class semiring_div provides basic abstract properties of semirings
  1042 with division and modulo operations.  Subsumes former class dvd_mod.
  1043 
  1044 * Merged theories IntDef, Numeral and IntArith into unified theory
  1045 Int.  INCOMPATIBILITY.
  1046 
  1047 * Theory Library/Code_Index: type "index" now represents natural
  1048 numbers rather than integers.  INCOMPATIBILITY.
  1049 
  1050 * New class "uminus" with operation "uminus" (split of from class
  1051 "minus" which now only has operation "minus", binary).
  1052 INCOMPATIBILITY.
  1053 
  1054 * Constants "card", "internal_split", "option_map" now with authentic
  1055 syntax.  INCOMPATIBILITY.
  1056 
  1057 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1058 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1059 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1060 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1061 Sup_set_def, le_def, less_def, option_map_def now with object
  1062 equality.  INCOMPATIBILITY.
  1063 
  1064 * Records. Removed K_record, and replaced it by pure lambda term
  1065 %x. c. The simplifier setup is now more robust against eta expansion.
  1066 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1067 
  1068 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1069 
  1070 * Library/ListVector: new theory of arithmetic vector operations.
  1071 
  1072 * Library/Order_Relation: new theory of various orderings as sets of
  1073 pairs.  Defines preorders, partial orders, linear orders and
  1074 well-orders on sets and on types.
  1075 
  1076 
  1077 *** ZF ***
  1078 
  1079 * Renamed some theories to allow to loading both ZF and HOL in the
  1080 same session:
  1081 
  1082   Datatype  -> Datatype_ZF
  1083   Inductive -> Inductive_ZF
  1084   Int       -> Int_ZF
  1085   IntDiv    -> IntDiv_ZF
  1086   Nat       -> Nat_ZF
  1087   List      -> List_ZF
  1088   Main      -> Main_ZF
  1089 
  1090 INCOMPATIBILITY: ZF theories that import individual theories below
  1091 Main might need to be adapted.  Regular theory Main is still
  1092 available, as trivial extension of Main_ZF.
  1093 
  1094 
  1095 *** ML ***
  1096 
  1097 * ML within Isar: antiquotation @{const name} or @{const
  1098 name(typargs)} produces statically-checked Const term.
  1099 
  1100 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1101 (of the same name).  Removed obsolete print command.
  1102 
  1103 * Removed obsolete "use_legacy_bindings" function.
  1104 
  1105 * The ``print mode'' is now a thread-local value derived from a global
  1106 template (the former print_mode reference), thus access becomes
  1107 non-critical.  The global print_mode reference is for session
  1108 management only; user-code should use print_mode_value,
  1109 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1110 
  1111 * Functions system/system_out provide a robust way to invoke external
  1112 shell commands, with propagation of interrupts (requires Poly/ML
  1113 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1114 
  1115 
  1116 *** System ***
  1117 
  1118 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1119 in accordance with Proof General 3.7, which prefers GNU emacs.
  1120 
  1121 * isatool tty runs Isabelle process with plain tty interaction;
  1122 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1123 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1124 
  1125 * isatool browser now works with Cygwin as well, using general
  1126 "javapath" function defined in Isabelle process environment.
  1127 
  1128 * YXML notation provides a simple and efficient alternative to
  1129 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1130 isatool yxml as described in the Isabelle system manual.
  1131 
  1132 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1133 provides general wrapper for managing an Isabelle process in a robust
  1134 fashion, with ``cooked'' output from stdin/stderr.
  1135 
  1136 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1137 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1138 
  1139 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1140 way of changing the user's settings is via
  1141 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1142 script.
  1143 
  1144 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1145 cores of the underlying machine, which is a good starting point for
  1146 optimal performance tuning.  The corresponding usedir option -M allows
  1147 "max" as an alias for "0".  WARNING: does not work on certain versions
  1148 of Mac OS (with Poly/ML 5.1).
  1149 
  1150 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1151 adverse effect of Isabelle flooding interactive front-ends (notably
  1152 ProofGeneral / XEmacs).
  1153 
  1154 
  1155 
  1156 New in Isabelle2007 (November 2007)
  1157 -----------------------------------
  1158 
  1159 *** General ***
  1160 
  1161 * More uniform information about legacy features, notably a
  1162 warning/error of "Legacy feature: ...", depending on the state of the
  1163 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1164 legacy features will disappear eventually.
  1165 
  1166 * Theory syntax: the header format ``theory A = B + C:'' has been
  1167 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1168 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1169 
  1170 * Theory syntax: the old non-Isar theory file format has been
  1171 discontinued altogether.  Note that ML proof scripts may still be used
  1172 with Isar theories; migration is usually quite simple with the ML
  1173 function use_legacy_bindings.  INCOMPATIBILITY.
  1174 
  1175 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1176 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1177 quotes.
  1178 
  1179 * Theory loader: be more serious about observing the static theory
  1180 header specifications (including optional directories), but not the
  1181 accidental file locations of previously successful loads.  The strict
  1182 update policy of former update_thy is now already performed by
  1183 use_thy, so the former has been removed; use_thys updates several
  1184 theories simultaneously, just as 'imports' within a theory header
  1185 specification, but without merging the results.  Potential
  1186 INCOMPATIBILITY: may need to refine theory headers and commands
  1187 ROOT.ML which depend on load order.
  1188 
  1189 * Theory loader: optional support for content-based file
  1190 identification, instead of the traditional scheme of full physical
  1191 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1192 (cf. the system manual).  The new scheme allows to work with
  1193 non-finished theories in persistent session images, such that source
  1194 files may be moved later on without requiring reloads.
  1195 
  1196 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1197 file (with the same base name as the theory) are considered a legacy
  1198 feature, which will disappear eventually. Even now, the theory loader
  1199 no longer maintains dependencies on such files.
  1200 
  1201 * Syntax: the scope for resolving ambiguities via type-inference is
  1202 now limited to individual terms, instead of whole simultaneous
  1203 specifications as before. This greatly reduces the complexity of the
  1204 syntax module and improves flexibility by separating parsing and
  1205 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1206 'fixes' etc.) are required in rare situations.
  1207 
  1208 * Syntax: constants introduced by new-style packages ('definition',
  1209 'abbreviation' etc.) are passed through the syntax module in
  1210 ``authentic mode''. This means that associated mixfix annotations
  1211 really stick to such constants, independently of potential name space
  1212 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1213 trees are represented slightly differently, may need to adapt syntax
  1214 translations accordingly. Use CONST marker in 'translations' and
  1215 @{const_syntax} antiquotation in 'parse_translation' etc.
  1216 
  1217 * Legacy goal package: reduced interface to the bare minimum required
  1218 to keep existing proof scripts running.  Most other user-level
  1219 functions are now part of the OldGoals structure, which is *not* open
  1220 by default (consider isatool expandshort before open OldGoals).
  1221 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1222 these tend to cause confusion about the actual goal (!) context being
  1223 used here, which is not necessarily the same as the_context().
  1224 
  1225 * Command 'find_theorems': supports "*" wild-card in "name:"
  1226 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1227 support a specific search form (see ProofGeneral/CHANGES).
  1228 
  1229 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1230 by default, which means that "prems" (and also "fixed variables") are
  1231 suppressed from proof state output.  Note that the ProofGeneral
  1232 settings mechanism allows to change and save options persistently, but
  1233 older versions of Isabelle will fail to start up if a negative prems
  1234 limit is imposed.
  1235 
  1236 * Local theory targets may be specified by non-nested blocks of
  1237 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1238 contain definitions, theorems etc., including any derived mechanism
  1239 that has been implemented on top of these primitives.  This concept
  1240 generalizes the existing ``theorem (in ...)'' towards more versatility
  1241 and scalability.
  1242 
  1243 * Proof General interface: proper undo of final 'end' command;
  1244 discontinued Isabelle/classic mode (ML proof scripts).
  1245 
  1246 
  1247 *** Document preparation ***
  1248 
  1249 * Added antiquotation @{theory name} which prints the given name,
  1250 after checking that it refers to a valid ancestor theory in the
  1251 current context.
  1252 
  1253 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1254 check the given source text as ML type/structure, printing verbatim.
  1255 
  1256 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1257 "c args == rhs" given in the current context.  (Any number of
  1258 arguments may be given on the LHS.)
  1259 
  1260 
  1261 *** Pure ***
  1262 
  1263 * The 'class' package offers a combination of axclass and locale to
  1264 achieve Haskell-like type classes in Isabelle.  Definitions and
  1265 theorems within a class context produce both relative results (with
  1266 implicit parameters according to the locale context), and polymorphic
  1267 constants with qualified polymorphism (according to the class
  1268 context).  Within the body context of a 'class' target, a separate
  1269 syntax layer ("user space type system") takes care of converting
  1270 between global polymorphic consts and internal locale representation.
  1271 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1272 "isatool doc classes" provides a tutorial.
  1273 
  1274 * Generic code generator framework allows to generate executable
  1275 code for ML and Haskell (including Isabelle classes).  A short usage
  1276 sketch:
  1277 
  1278     internal compilation:
  1279         export_code <list of constants (term syntax)> in SML
  1280     writing SML code to a file:
  1281         export_code <list of constants (term syntax)> in SML <filename>
  1282     writing OCaml code to a file:
  1283         export_code <list of constants (term syntax)> in OCaml <filename>
  1284     writing Haskell code to a bunch of files:
  1285         export_code <list of constants (term syntax)> in Haskell <filename>
  1286 
  1287     evaluating closed propositions to True/False using code generation:
  1288         method ``eval''
  1289 
  1290 Reasonable default setup of framework in HOL.
  1291 
  1292 Theorem attributs for selecting and transforming function equations theorems:
  1293 
  1294     [code fun]:        select a theorem as function equation for a specific constant
  1295     [code fun del]:    deselect a theorem as function equation for a specific constant
  1296     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1297     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1298 
  1299 User-defined serializations (target in {SML, OCaml, Haskell}):
  1300 
  1301     code_const <and-list of constants (term syntax)>
  1302       {(target) <and-list of const target syntax>}+
  1303 
  1304     code_type <and-list of type constructors>
  1305       {(target) <and-list of type target syntax>}+
  1306 
  1307     code_instance <and-list of instances>
  1308       {(target)}+
  1309         where instance ::= <type constructor> :: <class>
  1310 
  1311     code_class <and_list of classes>
  1312       {(target) <and-list of class target syntax>}+
  1313         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1314 
  1315 code_instance and code_class only are effective to target Haskell.
  1316 
  1317 For example usage see src/HOL/ex/Codegenerator.thy and
  1318 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1319 generation from Isabelle/HOL theories is available via "isatool doc
  1320 codegen".
  1321 
  1322 * Code generator: consts in 'consts_code' Isar commands are now
  1323 referred to by usual term syntax (including optional type
  1324 annotations).
  1325 
  1326 * Command 'no_translations' removes translation rules from theory
  1327 syntax.
  1328 
  1329 * Overloaded definitions are now actually checked for acyclic
  1330 dependencies.  The overloading scheme is slightly more general than
  1331 that of Haskell98, although Isabelle does not demand an exact
  1332 correspondence to type class and instance declarations.
  1333 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1334 exotic versions of overloading -- at the discretion of the user!
  1335 
  1336 Polymorphic constants are represented via type arguments, i.e. the
  1337 instantiation that matches an instance against the most general
  1338 declaration given in the signature.  For example, with the declaration
  1339 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1340 as c(nat).  Overloading is essentially simultaneous structural
  1341 recursion over such type arguments.  Incomplete specification patterns
  1342 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1343 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1344 Command 'print_theory' outputs the normalized system of recursive
  1345 equations, see section "definitions".
  1346 
  1347 * Configuration options are maintained within the theory or proof
  1348 context (with name and type bool/int/string), providing a very simple
  1349 interface to a poor-man's version of general context data.  Tools may
  1350 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1351 these values using Config.get etc.  Users may change options via an
  1352 associated attribute of the same name.  This form of context
  1353 declaration works particularly well with commands 'declare' or
  1354 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1355 very easy to avoid global references, which would not observe Isar
  1356 toplevel undo/redo and fail to work with multithreading.
  1357 
  1358 Various global ML references of Pure and HOL have been turned into
  1359 configuration options:
  1360 
  1361   Unify.search_bound		unify_search_bound
  1362   Unify.trace_bound		unify_trace_bound
  1363   Unify.trace_simp		unify_trace_simp
  1364   Unify.trace_types		unify_trace_types
  1365   Simplifier.simp_depth_limit	simp_depth_limit
  1366   Blast.depth_limit		blast_depth_limit
  1367   DatatypeProp.dtK		datatype_distinctness_limit
  1368   fast_arith_neq_limit  	fast_arith_neq_limit
  1369   fast_arith_split_limit	fast_arith_split_limit
  1370 
  1371 * Named collections of theorems may be easily installed as context
  1372 data using the functor NamedThmsFun (see also
  1373 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1374 attributes; there is also a toplevel print command.  This facility is
  1375 just a common case of general context data, which is the preferred way
  1376 for anything more complex than just a list of facts in canonical
  1377 order.
  1378 
  1379 * Isar: command 'declaration' augments a local theory by generic
  1380 declaration functions written in ML.  This enables arbitrary content
  1381 being added to the context, depending on a morphism that tells the
  1382 difference of the original declaration context wrt. the application
  1383 context encountered later on.
  1384 
  1385 * Isar: proper interfaces for simplification procedures.  Command
  1386 'simproc_setup' declares named simprocs (with match patterns, and body
  1387 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1388 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1389 
  1390 * Isar: an extra pair of brackets around attribute declarations
  1391 abbreviates a theorem reference involving an internal dummy fact,
  1392 which will be ignored later --- only the effect of the attribute on
  1393 the background context will persist.  This form of in-place
  1394 declarations is particularly useful with commands like 'declare' and
  1395 'using', for example ``have A using [[simproc a]] by simp''.
  1396 
  1397 * Isar: method "assumption" (and implicit closing of subproofs) now
  1398 takes simple non-atomic goal assumptions into account: after applying
  1399 an assumption as a rule the resulting subgoals are solved by atomic
  1400 assumption steps.  This is particularly useful to finish 'obtain'
  1401 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1402 without referring to the original premise "!!x. P x ==> thesis" in the
  1403 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1404 more permissive.
  1405 
  1406 * Isar: implicit use of prems from the Isar proof context is
  1407 considered a legacy feature.  Common applications like ``have A .''
  1408 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1409 referencing facts explicitly here improves readability and
  1410 maintainability of proof texts.
  1411 
  1412 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1413 the obtained context from the course of reasoning!  For example:
  1414 
  1415   assume "EX x y. A x & B y"   -- "any previous fact"
  1416   then guess x and y by clarify
  1417 
  1418 This technique is potentially adventurous, depending on the facts and
  1419 proof tools being involved here.
  1420 
  1421 * Isar: known facts from the proof context may be specified as literal
  1422 propositions, using ASCII back-quote syntax.  This works wherever
  1423 named facts used to be allowed so far, in proof commands, proof
  1424 methods, attributes etc.  Literal facts are retrieved from the context
  1425 according to unification of type and term parameters.  For example,
  1426 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1427 theorems in the current context, then these are valid literal facts:
  1428 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1429 
  1430 There is also a proof method "fact" which does the same composition
  1431 for explicit goal states, e.g. the following proof texts coincide with
  1432 certain special cases of literal facts:
  1433 
  1434   have "A" by fact                 ==  note `A`
  1435   have "A ==> B" by fact           ==  note `A ==> B`
  1436   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1437   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1438 
  1439 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1440 outer syntax.  Thus symbolic identifiers may be used without
  1441 additional white space in declarations like this: ``assume *: A''.
  1442 
  1443 * Isar: 'print_facts' prints all local facts of the current context,
  1444 both named and unnamed ones.
  1445 
  1446 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1447 
  1448   def x == "t" and y == "u"
  1449 
  1450 * Isar: added command 'unfolding', which is structurally similar to
  1451 'using', but affects both the goal state and facts by unfolding given
  1452 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1453 'unfolded' attribute may be replaced by first-class proof text.
  1454 
  1455 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1456 and command 'unfolding' now all support object-level equalities
  1457 (potentially conditional).  The underlying notion of rewrite rule is
  1458 analogous to the 'rule_format' attribute, but *not* that of the
  1459 Simplifier (which is usually more generous).
  1460 
  1461 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1462 premises of a theorem by n. Useful in conjunction with drule.
  1463 
  1464 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1465 method expression within a sandbox consisting of the first N
  1466 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1467 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1468 simplifies all new goals that emerge from applying rule foo to the
  1469 originally first one.
  1470 
  1471 * Isar: schematic goals are no longer restricted to higher-order
  1472 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1473 expected.
  1474 
  1475 * Isar: the conclusion of a long theorem statement is now either
  1476 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1477 (essentially a disjunction of cases with local parameters and
  1478 assumptions).  The latter allows to express general elimination rules
  1479 adequately; in this notation common elimination rules look like this:
  1480 
  1481   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1482     assumes "EX x. P x"
  1483     obtains x where "P x"
  1484 
  1485   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1486     assumes "A & B"
  1487     obtains A and B
  1488 
  1489   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1490     assumes "A | B"
  1491     obtains
  1492       A
  1493     | B
  1494 
  1495 The subsequent classical rules even refer to the formal "thesis"
  1496 explicitly:
  1497 
  1498   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1499     obtains "~ thesis"
  1500 
  1501   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1502     obtains "thesis ==> something"
  1503 
  1504 The actual proof of an 'obtains' statement is analogous to that of the
  1505 Isar proof element 'obtain', only that there may be several cases.
  1506 Optional case names may be specified in parentheses; these will be
  1507 available both in the present proof and as annotations in the
  1508 resulting rule, for later use with the 'cases' method (cf. attribute
  1509 case_names).
  1510 
  1511 * Isar: the assumptions of a long theorem statement are available as
  1512 "assms" fact in the proof context.  This is more appropriate than the
  1513 (historical) "prems", which refers to all assumptions of the current
  1514 context, including those from the target locale, proof body etc.
  1515 
  1516 * Isar: 'print_statement' prints theorems from the current theory or
  1517 proof context in long statement form, according to the syntax of a
  1518 top-level lemma.
  1519 
  1520 * Isar: 'obtain' takes an optional case name for the local context
  1521 introduction rule (default "that").
  1522 
  1523 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1524 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1525 to occur.
  1526 
  1527 * Pure: syntax "CONST name" produces a fully internalized constant
  1528 according to the current context.  This is particularly useful for
  1529 syntax translations that should refer to internal constant
  1530 representations independently of name spaces.
  1531 
  1532 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1533 instead of "FOO ". This allows multiple binder declarations to coexist
  1534 in the same context.  INCOMPATIBILITY.
  1535 
  1536 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1537 primitive that also works in a locale context (both for constants and
  1538 fixed variables). Type declaration and internal syntactic representation
  1539 of given constants retrieved from the context. Likewise, the
  1540 'no_notation' command allows to remove given syntax annotations from the
  1541 current context.
  1542 
  1543 * Isar/locales: new derived specification elements 'axiomatization',
  1544 'definition', 'abbreviation', which support type-inference, admit
  1545 object-level specifications (equality, equivalence).  See also the
  1546 isar-ref manual.  Examples:
  1547 
  1548   axiomatization
  1549     eq  (infix "===" 50) where
  1550     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1551 
  1552   definition "f x y = x + y + 1"
  1553   definition g where "g x = f x x"
  1554 
  1555   abbreviation
  1556     neq  (infix "=!=" 50) where
  1557     "x =!= y == ~ (x === y)"
  1558 
  1559 These specifications may be also used in a locale context.  Then the
  1560 constants being introduced depend on certain fixed parameters, and the
  1561 constant name is qualified by the locale base name.  An internal
  1562 abbreviation takes care for convenient input and output, making the
  1563 parameters implicit and using the original short name.  See also
  1564 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1565 entities from a monomorphic theory.
  1566 
  1567 Presently, abbreviations are only available 'in' a target locale, but
  1568 not inherited by general import expressions.  Also note that
  1569 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1570 'translations' in common applications.  The "no_abbrevs" print mode
  1571 prevents folding of abbreviations in term output.
  1572 
  1573 Concrete syntax is attached to specified constants in internal form,
  1574 independently of name spaces.  The parse tree representation is
  1575 slightly different -- use 'notation' instead of raw 'syntax', and
  1576 'translations' with explicit "CONST" markup to accommodate this.
  1577 
  1578 * Pure/Isar: unified syntax for new-style specification mechanisms
  1579 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1580 full type inference and dummy patterns ("_").  For example:
  1581 
  1582   definition "K x _ = x"
  1583 
  1584   inductive conj for A B
  1585   where "A ==> B ==> conj A B"
  1586 
  1587 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1588 the current context.  Print mode "no_abbrevs" prevents inversion of
  1589 abbreviations on output.
  1590 
  1591 * Isar/locales: improved parameter handling: use of locales "var" and
  1592 "struct" no longer necessary; - parameter renamings are no longer
  1593 required to be injective.  For example, this allows to define
  1594 endomorphisms as locale endom = homom mult mult h.
  1595 
  1596 * Isar/locales: changed the way locales with predicates are defined.
  1597 Instead of accumulating the specification, the imported expression is
  1598 now an interpretation.  INCOMPATIBILITY: different normal form of
  1599 locale expressions.  In particular, in interpretations of locales with
  1600 predicates, goals repesenting already interpreted fragments are not
  1601 removed automatically.  Use methods `intro_locales' and
  1602 `unfold_locales'; see below.
  1603 
  1604 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1605 provide backward reasoning on locales predicates.  The methods are
  1606 aware of interpretations and discharge corresponding goals.
  1607 `intro_locales' is less aggressive then `unfold_locales' and does not
  1608 unfold predicates to assumptions.
  1609 
  1610 * Isar/locales: the order in which locale fragments are accumulated
  1611 has changed.  This enables to override declarations from fragments due
  1612 to interpretations -- for example, unwanted simp rules.
  1613 
  1614 * Isar/locales: interpretation in theories and proof contexts has been
  1615 extended.  One may now specify (and prove) equations, which are
  1616 unfolded in interpreted theorems.  This is useful for replacing
  1617 defined concepts (constants depending on locale parameters) by
  1618 concepts already existing in the target context.  Example:
  1619 
  1620   interpretation partial_order ["op <= :: [int, int] => bool"]
  1621     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1622 
  1623 Typically, the constant `partial_order.less' is created by a
  1624 definition specification element in the context of locale
  1625 partial_order.
  1626 
  1627 * Method "induct": improved internal context management to support
  1628 local fixes and defines on-the-fly. Thus explicit meta-level
  1629 connectives !!  and ==> are rarely required anymore in inductive goals
  1630 (using object-logic connectives for this purpose has been long
  1631 obsolete anyway). Common proof patterns are explained in
  1632 src/HOL/Induct/Common_Patterns.thy, see also
  1633 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1634 examples.
  1635 
  1636 * Method "induct": improved handling of simultaneous goals. Instead of
  1637 introducing object-level conjunction, the statement is now split into
  1638 several conclusions, while the corresponding symbolic cases are nested
  1639 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1640 see src/HOL/Induct/Common_Patterns.thy, for example.
  1641 
  1642 * Method "induct": mutual induction rules are now specified as a list
  1643 of rule sharing the same induction cases. HOL packages usually provide
  1644 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1645 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1646 mutual induction rules differently, i.e. like this:
  1647 
  1648   (induct rule: foo_bar.inducts)
  1649   (induct set: foo bar)
  1650   (induct pred: foo bar)
  1651   (induct type: foo bar)
  1652 
  1653 The ML function ProjectRule.projections turns old-style rules into the
  1654 new format.
  1655 
  1656 * Method "coinduct": dual of induction, see
  1657 src/HOL/Library/Coinductive_List.thy for various examples.
  1658 
  1659 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1660 considered a legacy feature.
  1661 
  1662 * Attribute "symmetric" produces result with standardized schematic
  1663 variables (index 0).  Potential INCOMPATIBILITY.
  1664 
  1665 * Simplifier: by default the simplifier trace only shows top level
  1666 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1667 default. Thus there is less danger of being flooded by the trace. The
  1668 trace indicates where parts have been suppressed.
  1669   
  1670 * Provers/classical: removed obsolete classical version of elim_format
  1671 attribute; classical elim/dest rules are now treated uniformly when
  1672 manipulating the claset.
  1673 
  1674 * Provers/classical: stricter checks to ensure that supplied intro,
  1675 dest and elim rules are well-formed; dest and elim rules must have at
  1676 least one premise.
  1677 
  1678 * Provers/classical: attributes dest/elim/intro take an optional
  1679 weight argument for the rule (just as the Pure versions).  Weights are
  1680 ignored by automated tools, but determine the search order of single
  1681 rule steps.
  1682 
  1683 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1684 where the body does not mention the bound variable.  Note that dummy
  1685 patterns implicitly depend on their context of bounds, which makes
  1686 "{_. _}" match any set comprehension as expected.  Potential
  1687 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1688 constant "_idtdummy" in the binding position.
  1689 
  1690 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1691 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1692 for example "A -> B" => "Pi A (%_. B)".
  1693 
  1694 * Pure: 'class_deps' command visualizes the subclass relation, using
  1695 the graph browser tool.
  1696 
  1697 * Pure: 'print_theory' now suppresses certain internal declarations by
  1698 default; use '!' option for full details.
  1699 
  1700 
  1701 *** HOL ***
  1702 
  1703 * Method "metis" proves goals by applying the Metis general-purpose
  1704 resolution prover (see also http://gilith.com/software/metis/).
  1705 Examples are in the directory MetisExamples.  WARNING: the
  1706 Isabelle/HOL-Metis integration does not yet work properly with
  1707 multi-threading.
  1708   
  1709 * Command 'sledgehammer' invokes external automatic theorem provers as
  1710 background processes.  It generates calls to the "metis" method if
  1711 successful. These can be pasted into the proof.  Users do not have to
  1712 wait for the automatic provers to return.  WARNING: does not really
  1713 work with multi-threading.
  1714 
  1715 * New "auto_quickcheck" feature tests outermost goal statements for
  1716 potential counter-examples.  Controlled by ML references
  1717 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1718 5000 milliseconds).  Fails silently if statements is outside of
  1719 executable fragment, or any other codgenerator problem occurs.
  1720 
  1721 * New constant "undefined" with axiom "undefined x = undefined".
  1722 
  1723 * Added class "HOL.eq", allowing for code generation with polymorphic
  1724 equality.
  1725 
  1726 * Some renaming of class constants due to canonical name prefixing in
  1727 the new 'class' package:
  1728 
  1729     HOL.abs ~> HOL.abs_class.abs
  1730     HOL.divide ~> HOL.divide_class.divide
  1731     0 ~> HOL.zero_class.zero
  1732     1 ~> HOL.one_class.one
  1733     op + ~> HOL.plus_class.plus
  1734     op - ~> HOL.minus_class.minus
  1735     uminus ~> HOL.minus_class.uminus
  1736     op * ~> HOL.times_class.times
  1737     op < ~> HOL.ord_class.less
  1738     op <= > HOL.ord_class.less_eq
  1739     Nat.power ~> Power.power_class.power
  1740     Nat.size ~> Nat.size_class.size
  1741     Numeral.number_of ~> Numeral.number_class.number_of
  1742     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1743     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1744     Orderings.min ~> Orderings.ord_class.min
  1745     Orderings.max ~> Orderings.ord_class.max
  1746     Divides.op div ~> Divides.div_class.div
  1747     Divides.op mod ~> Divides.div_class.mod
  1748     Divides.op dvd ~> Divides.div_class.dvd
  1749 
  1750 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1751 
  1752 a) User-defined constants using any of the names "plus", "minus",
  1753 "times", "less" or "less_eq". The standard syntax translations for
  1754 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1755 names.
  1756 
  1757 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1758 INCOMPATIBILITY: use more specific names.
  1759 
  1760 c) Permutative equations (e.g. "a + b = b + a")
  1761 Since the change of names also changes the order of terms, permutative
  1762 rewrite rules may get applied in a different order. Experience shows
  1763 that this is rarely the case (only two adaptions in the whole Isabelle
  1764 distribution).  INCOMPATIBILITY: rewrite proofs
  1765 
  1766 d) ML code directly refering to constant names
  1767 This in general only affects hand-written proof tactics, simprocs and
  1768 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1769 Consider using @{const_name} antiquotation.
  1770 
  1771 * New class "default" with associated constant "default".
  1772 
  1773 * Function "sgn" is now overloaded and available on int, real, complex
  1774 (and other numeric types), using class "sgn".  Two possible defs of
  1775 sgn are given as equational assumptions in the classes sgn_if and
  1776 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1777 INCOMPATIBILITY.
  1778 
  1779 * Locale "partial_order" now unified with class "order" (cf. theory
  1780 Orderings), added parameter "less".  INCOMPATIBILITY.
  1781 
  1782 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1783 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1784 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1785 
  1786 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1787 changed order of proof goals in instance proofs.
  1788 
  1789 * The transitivity reasoner for partial and linear orders is set up
  1790 for classes "order" and "linorder".  Instances of the reasoner are available
  1791 in all contexts importing or interpreting the corresponding locales.
  1792 Method "order" invokes the reasoner separately; the reasoner
  1793 is also integrated with the Simplifier as a solver.  Diagnostic
  1794 command 'print_orders' shows the available instances of the reasoner
  1795 in the current context.
  1796 
  1797 * Localized monotonicity predicate in theory "Orderings"; integrated
  1798 lemmas max_of_mono and min_of_mono with this predicate.
  1799 INCOMPATIBILITY.
  1800 
  1801 * Formulation of theorem "dense" changed slightly due to integration
  1802 with new class dense_linear_order.
  1803 
  1804 * Uniform lattice theory development in HOL.
  1805 
  1806     constants "meet" and "join" now named "inf" and "sup"
  1807     constant "Meet" now named "Inf"
  1808 
  1809     classes "meet_semilorder" and "join_semilorder" now named
  1810       "lower_semilattice" and "upper_semilattice"
  1811     class "lorder" now named "lattice"
  1812     class "comp_lat" now named "complete_lattice"
  1813 
  1814     Instantiation of lattice classes allows explicit definitions
  1815     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1816 
  1817   INCOMPATIBILITY.  Theorem renames:
  1818 
  1819     meet_left_le            ~> inf_le1
  1820     meet_right_le           ~> inf_le2
  1821     join_left_le            ~> sup_ge1
  1822     join_right_le           ~> sup_ge2
  1823     meet_join_le            ~> inf_sup_ord
  1824     le_meetI                ~> le_infI
  1825     join_leI                ~> le_supI
  1826     le_meet                 ~> le_inf_iff
  1827     le_join                 ~> ge_sup_conv
  1828     meet_idempotent         ~> inf_idem
  1829     join_idempotent         ~> sup_idem
  1830     meet_comm               ~> inf_commute
  1831     join_comm               ~> sup_commute
  1832     meet_leI1               ~> le_infI1
  1833     meet_leI2               ~> le_infI2
  1834     le_joinI1               ~> le_supI1
  1835     le_joinI2               ~> le_supI2
  1836     meet_assoc              ~> inf_assoc
  1837     join_assoc              ~> sup_assoc
  1838     meet_left_comm          ~> inf_left_commute
  1839     meet_left_idempotent    ~> inf_left_idem
  1840     join_left_comm          ~> sup_left_commute
  1841     join_left_idempotent    ~> sup_left_idem
  1842     meet_aci                ~> inf_aci
  1843     join_aci                ~> sup_aci
  1844     le_def_meet             ~> le_iff_inf
  1845     le_def_join             ~> le_iff_sup
  1846     join_absorp2            ~> sup_absorb2
  1847     join_absorp1            ~> sup_absorb1
  1848     meet_absorp1            ~> inf_absorb1
  1849     meet_absorp2            ~> inf_absorb2
  1850     meet_join_absorp        ~> inf_sup_absorb
  1851     join_meet_absorp        ~> sup_inf_absorb
  1852     distrib_join_le         ~> distrib_sup_le
  1853     distrib_meet_le         ~> distrib_inf_le
  1854 
  1855     add_meet_distrib_left   ~> add_inf_distrib_left
  1856     add_join_distrib_left   ~> add_sup_distrib_left
  1857     is_join_neg_meet        ~> is_join_neg_inf
  1858     is_meet_neg_join        ~> is_meet_neg_sup
  1859     add_meet_distrib_right  ~> add_inf_distrib_right
  1860     add_join_distrib_right  ~> add_sup_distrib_right
  1861     add_meet_join_distribs  ~> add_sup_inf_distribs
  1862     join_eq_neg_meet        ~> sup_eq_neg_inf
  1863     meet_eq_neg_join        ~> inf_eq_neg_sup
  1864     add_eq_meet_join        ~> add_eq_inf_sup
  1865     meet_0_imp_0            ~> inf_0_imp_0
  1866     join_0_imp_0            ~> sup_0_imp_0
  1867     meet_0_eq_0             ~> inf_0_eq_0
  1868     join_0_eq_0             ~> sup_0_eq_0
  1869     neg_meet_eq_join        ~> neg_inf_eq_sup
  1870     neg_join_eq_meet        ~> neg_sup_eq_inf
  1871     join_eq_if              ~> sup_eq_if
  1872 
  1873     mono_meet               ~> mono_inf
  1874     mono_join               ~> mono_sup
  1875     meet_bool_eq            ~> inf_bool_eq
  1876     join_bool_eq            ~> sup_bool_eq
  1877     meet_fun_eq             ~> inf_fun_eq
  1878     join_fun_eq             ~> sup_fun_eq
  1879     meet_set_eq             ~> inf_set_eq
  1880     join_set_eq             ~> sup_set_eq
  1881     meet1_iff               ~> inf1_iff
  1882     meet2_iff               ~> inf2_iff
  1883     meet1I                  ~> inf1I
  1884     meet2I                  ~> inf2I
  1885     meet1D1                 ~> inf1D1
  1886     meet2D1                 ~> inf2D1
  1887     meet1D2                 ~> inf1D2
  1888     meet2D2                 ~> inf2D2
  1889     meet1E                  ~> inf1E
  1890     meet2E                  ~> inf2E
  1891     join1_iff               ~> sup1_iff
  1892     join2_iff               ~> sup2_iff
  1893     join1I1                 ~> sup1I1
  1894     join2I1                 ~> sup2I1
  1895     join1I1                 ~> sup1I1
  1896     join2I2                 ~> sup1I2
  1897     join1CI                 ~> sup1CI
  1898     join2CI                 ~> sup2CI
  1899     join1E                  ~> sup1E
  1900     join2E                  ~> sup2E
  1901 
  1902     is_meet_Meet            ~> is_meet_Inf
  1903     Meet_bool_def           ~> Inf_bool_def
  1904     Meet_fun_def            ~> Inf_fun_def
  1905     Meet_greatest           ~> Inf_greatest
  1906     Meet_lower              ~> Inf_lower
  1907     Meet_set_def            ~> Inf_set_def
  1908 
  1909     Sup_def                 ~> Sup_Inf
  1910     Sup_bool_eq             ~> Sup_bool_def
  1911     Sup_fun_eq              ~> Sup_fun_def
  1912     Sup_set_eq              ~> Sup_set_def
  1913 
  1914     listsp_meetI            ~> listsp_infI
  1915     listsp_meet_eq          ~> listsp_inf_eq
  1916 
  1917     meet_min                ~> inf_min
  1918     join_max                ~> sup_max
  1919 
  1920 * Added syntactic class "size"; overloaded constant "size" now has
  1921 type "'a::size ==> bool"
  1922 
  1923 * Internal reorganisation of `size' of datatypes: size theorems
  1924 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1925 simplification rules by default!); theorems "prod.size" now named
  1926 "*.size".
  1927 
  1928 * Class "div" now inherits from class "times" rather than "type".
  1929 INCOMPATIBILITY.
  1930 
  1931 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1932 Linorder etc.  have disappeared; operations defined in terms of
  1933 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1934 
  1935 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1936 
  1937 * HOL-Word: New extensive library and type for generic, fixed size
  1938 machine words, with arithemtic, bit-wise, shifting and rotating
  1939 operations, reflection into int, nat, and bool lists, automation for
  1940 linear arithmetic (by automatic reflection into nat or int), including
  1941 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1942 arithmetic type classes, supporting automatic simplification of
  1943 numerals on all operations.
  1944 
  1945 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1946 
  1947 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1948 
  1949 * Code generator library theories:
  1950   - Code_Integer represents HOL integers by big integer literals in target
  1951     languages.
  1952   - Code_Char represents HOL characters by character literals in target
  1953     languages.
  1954   - Code_Char_chr like Code_Char, but also offers treatment of character
  1955     codes; includes Code_Integer.
  1956   - Executable_Set allows to generate code for finite sets using lists.
  1957   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1958     denominator).
  1959   - Executable_Real implements a subset of real numbers, namly those
  1960     representable by rational numbers.
  1961   - Efficient_Nat implements natural numbers by integers, which in general will
  1962     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1963     includes Code_Integer.
  1964   - Code_Index provides an additional datatype index which is mapped to
  1965     target-language built-in integers.
  1966   - Code_Message provides an additional datatype message_string which is isomorphic to
  1967     strings; messages are mapped to target-language strings.
  1968 
  1969 * New package for inductive predicates
  1970 
  1971   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1972 
  1973     inductive
  1974       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1975       for z_1 :: U_1 and ... and z_n :: U_m
  1976     where
  1977       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1978     | ...
  1979 
  1980   with full support for type-inference, rather than
  1981 
  1982     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1983 
  1984     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1985     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1986 
  1987     inductive "s z_1 ... z_m"
  1988     intros
  1989       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1990       ...
  1991 
  1992   For backward compatibility, there is a wrapper allowing inductive
  1993   sets to be defined with the new package via
  1994 
  1995     inductive_set
  1996       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1997       for z_1 :: U_1 and ... and z_n :: U_m
  1998     where
  1999       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2000     | ...
  2001 
  2002   or
  2003 
  2004     inductive_set
  2005       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2006       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2007       for z_1 :: U_1 and ... and z_n :: U_m
  2008     where
  2009       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2010     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2011     | ...
  2012 
  2013   if the additional syntax "p ..." is required.
  2014 
  2015   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2016   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2017 
  2018   INCOMPATIBILITIES:
  2019 
  2020   - Since declaration and definition of inductive sets or predicates
  2021     is no longer separated, abbreviations involving the newly
  2022     introduced sets or predicates must be specified together with the
  2023     introduction rules after the 'where' keyword (see above), rather
  2024     than before the actual inductive definition.
  2025 
  2026   - The variables in induction and elimination rules are now
  2027     quantified in the order of their occurrence in the introduction
  2028     rules, rather than in alphabetical order. Since this may break
  2029     some proofs, these proofs either have to be repaired, e.g. by
  2030     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2031     statements of the form
  2032 
  2033       case (rule_i a_i_1 ... a_i_{k_i})
  2034 
  2035     or the old order of quantification has to be restored by explicitly adding
  2036     meta-level quantifiers in the introduction rules, i.e.
  2037 
  2038       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2039 
  2040   - The format of the elimination rules is now
  2041 
  2042       p z_1 ... z_m x_1 ... x_n ==>
  2043         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2044         ==> ... ==> P
  2045 
  2046     for predicates and
  2047 
  2048       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2049         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2050         ==> ... ==> P
  2051 
  2052     for sets rather than
  2053 
  2054       x : s z_1 ... z_m ==>
  2055         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2056         ==> ... ==> P
  2057 
  2058     This may require terms in goals to be expanded to n-tuples
  2059     (e.g. using case_tac or simplification with the split_paired_all
  2060     rule) before the above elimination rule is applicable.
  2061 
  2062   - The elimination or case analysis rules for (mutually) inductive
  2063     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2064     list of rules "p_1_..._p_k.elims" is no longer available.
  2065 
  2066 * New package "function"/"fun" for general recursive functions,
  2067 supporting mutual and nested recursion, definitions in local contexts,
  2068 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2069 for small examples, and the separate tutorial on the function
  2070 package. The old recdef "package" is still available as before, but
  2071 users are encouraged to use the new package.
  2072 
  2073 * Method "lexicographic_order" automatically synthesizes termination
  2074 relations as lexicographic combinations of size measures. 
  2075 
  2076 * Case-expressions allow arbitrary constructor-patterns (including
  2077 "_") and take their order into account, like in functional
  2078 programming.  Internally, this is translated into nested
  2079 case-expressions; missing cases are added and mapped to the predefined
  2080 constant "undefined". In complicated cases printing may no longer show
  2081 the original input but the internal form. Lambda-abstractions allow
  2082 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2083 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2084 variable.
  2085 
  2086 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2087 is an abbreviation for "of_nat :: nat => int". The simplification
  2088 rules for "of_nat" have been changed to work like "int" did
  2089 previously.  Potential INCOMPATIBILITY:
  2090   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2091   - of_nat_diff and of_nat_mult are no longer default simp rules
  2092 
  2093 * Method "algebra" solves polynomial equations over (semi)rings using
  2094 Groebner bases. The (semi)ring structure is defined by locales and the
  2095 tool setup depends on that generic context. Installing the method for
  2096 a specific type involves instantiating the locale and possibly adding
  2097 declarations for computation on the coefficients.  The method is
  2098 already instantiated for natural numbers and for the axiomatic class
  2099 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2100 CALCULEMUS 2007 for the general principles underlying this
  2101 architecture of context-aware proof-tools.
  2102 
  2103 * Method "ferrack" implements quantifier elimination over
  2104 special-purpose dense linear orders using locales (analogous to
  2105 "algebra"). The method is already installed for class
  2106 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2107 rat, etc.
  2108 
  2109 * Former constant "List.op @" now named "List.append".  Use ML
  2110 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2111 circumvent possible incompatibilities when working on ML level.
  2112 
  2113 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2114 
  2115 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2116 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2117 
  2118 * New syntax for Haskell-like list comprehension (input only), eg.
  2119 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2120 
  2121 * The special syntax for function "filter" has changed from [x :
  2122 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2123 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2124 
  2125 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2126 defined on nat only, as an abbreviation for [a..<Suc b]
  2127 INCOMPATIBILITY.
  2128 
  2129 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2130 
  2131 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2132 
  2133 * New lemma collection field_simps (an extension of ring_simps) for
  2134 manipulating (in)equations involving division. Multiplies with all
  2135 denominators that can be proved to be non-zero (in equations) or
  2136 positive/negative (in inequations).
  2137 
  2138 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2139 have been improved and renamed to ring_simps, group_simps and
  2140 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2141 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2142 
  2143 * Theory Library/Commutative_Ring: switched from recdef to function
  2144 package; constants add, mul, pow now curried.  Infix syntax for
  2145 algebraic operations.
  2146 
  2147 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2148 INCOMPATIBILITY.
  2149 
  2150 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2151 INCOMPATIBILITY.
  2152 
  2153 * HOL/records: generalised field-update to take a function on the
  2154 field rather than the new value: r(|A := x|) is translated to A_update
  2155 (K x) r The K-combinator that is internally used is called K_record.
  2156 INCOMPATIBILITY: Usage of the plain update functions has to be
  2157 adapted.
  2158  
  2159 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2160 * x = 0, which are required for a semiring.  Richer structures do not
  2161 inherit from semiring_0 anymore, because this property is a theorem
  2162 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2163 there is more to prove, but this is mostly trivial.
  2164 
  2165 * Class "recpower" is generalized to arbitrary monoids, not just
  2166 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2167 commutativity or semiring properties additionally.
  2168 
  2169 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2170 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2171 better use 'abbreviation'.
  2172 
  2173 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2174 
  2175 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2176 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2177 significant changes for setting up numeral syntax for types:
  2178   - New constants Numeral.pred and Numeral.succ instead
  2179       of former Numeral.bin_pred and Numeral.bin_succ.
  2180   - Use integer operations instead of bin_add, bin_mult and so on.
  2181   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2182   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2183 
  2184 See src/HOL/Integ/IntArith.thy for an example setup.
  2185 
  2186 * Command 'normal_form' computes the normal form of a term that may
  2187 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2188 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2189 heavy-duty computations because the functions are compiled to ML
  2190 first.  Correspondingly, a method "normalization" is provided.  See
  2191 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2192 
  2193 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2194 25 like -->); output depends on the "iff" print_mode, the default is
  2195 "A = B" (with priority 50).
  2196 
  2197 * Relations less (<) and less_eq (<=) are also available on type bool.
  2198 Modified syntax to disallow nesting without explicit parentheses,
  2199 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2200 INCOMPATIBILITY.
  2201 
  2202 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2203 
  2204 * Relation composition operator "op O" now has precedence 75 and binds
  2205 stronger than union and intersection. INCOMPATIBILITY.
  2206 
  2207 * The old set interval syntax "{m..n(}" (and relatives) has been
  2208 removed.  Use "{m..<n}" (and relatives) instead.
  2209 
  2210 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2211 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2212 ``declare [[simproc del: neq]]''.
  2213 
  2214 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2215 True/False.
  2216 
  2217 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2218 
  2219 * Theorem setsum_mult renamed to setsum_right_distrib.
  2220 
  2221 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2222 ``rule'' method.
  2223 
  2224 * Reimplemented methods "sat" and "satx", with several improvements:
  2225 goals no longer need to be stated as "<prems> ==> False", equivalences
  2226 (i.e. "=" on type bool) are handled, variable names of the form
  2227 "lit_<n>" are no longer reserved, significant speedup.
  2228 
  2229 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2230 zChaff is still supported as well.
  2231 
  2232 * 'inductive' and 'datatype': provide projections of mutual rules,
  2233 bundled as foo_bar.inducts;
  2234 
  2235 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2236 Library.
  2237 
  2238 * Library: moved theory Accessible_Part to main HOL.
  2239 
  2240 * Library: added theory Coinductive_List of potentially infinite lists
  2241 as greatest fixed-point.
  2242 
  2243 * Library: added theory AssocList which implements (finite) maps as
  2244 association lists.
  2245 
  2246 * Method "evaluation" solves goals (i.e. a boolean expression)
  2247 efficiently by compiling it to ML.  The goal is "proved" (via an
  2248 oracle) if it evaluates to True.
  2249 
  2250 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2251 also when invoked by the simplifier.  This results in the Simplifier
  2252 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2253 Configuration option fast_arith_split_limit=0 recovers the old
  2254 behavior.
  2255 
  2256 * Support for hex (0x20) and binary (0b1001) numerals.
  2257 
  2258 * New method: reify eqs (t), where eqs are equations for an
  2259 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2260 parameter, computes a term s::'b and a list xs::'a list and proves the
  2261 theorem I xs s = t. This is also known as reification or quoting. The
  2262 resulting theorem is applied to the subgoal to substitute t with I xs
  2263 s.  If t is omitted, the subgoal itself is reified.
  2264 
  2265 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2266 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2267 where f is supposed to be a computable function (in the sense of code
  2268 generattion). The method uses reify to compute s and xs as above then
  2269 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2270 r and finally gets the theorem t = r, which is again applied to the
  2271 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2272 
  2273 * Reflection: Automatic reification now handels binding, an example is
  2274 available in src/HOL/ex/ReflectionEx.thy
  2275 
  2276 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2277 command 'statespace' that is similar to 'record', but introduces an
  2278 abstract specification based on the locale infrastructure instead of
  2279 HOL types.  This leads to extra flexibility in composing state spaces,
  2280 in particular multiple inheritance and renaming of components.
  2281 
  2282 
  2283 *** HOL-Complex ***
  2284 
  2285 * Hyperreal: Functions root and sqrt are now defined on negative real
  2286 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2287 Nonnegativity side conditions have been removed from many lemmas, so
  2288 that more subgoals may now be solved by simplification; potential
  2289 INCOMPATIBILITY.
  2290 
  2291 * Real: new type classes formalize real normed vector spaces and
  2292 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2293 and norm :: 'a => real.
  2294 
  2295 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2296 reals into other types. The overloaded constant Reals :: 'a set is now
  2297 defined as range of_real; potential INCOMPATIBILITY.
  2298 
  2299 * Real: proper support for ML code generation, including 'quickcheck'.
  2300 Reals are implemented as arbitrary precision rationals.
  2301 
  2302 * Hyperreal: Several constants that previously worked only for the
  2303 reals have been generalized, so they now work over arbitrary vector
  2304 spaces. Type annotations may need to be added in some cases; potential
  2305 INCOMPATIBILITY.
  2306 
  2307   Infinitesimal  :: ('a::real_normed_vector) star set
  2308   HFinite        :: ('a::real_normed_vector) star set
  2309   HInfinite      :: ('a::real_normed_vector) star set
  2310   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2311   monad          :: ('a::real_normed_vector) star => 'a star set
  2312   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2313   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2314   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2315   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2316   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2317   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2318   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2319   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2320   sgn            :: 'a::real_normed_vector => 'a
  2321   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2322 
  2323 * Complex: Some complex-specific constants are now abbreviations for
  2324 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2325 hnorm.  Other constants have been entirely removed in favor of the
  2326 polymorphic versions (INCOMPATIBILITY):
  2327 
  2328   approx        <-- capprox
  2329   HFinite       <-- CFinite
  2330   HInfinite     <-- CInfinite
  2331   Infinitesimal <-- CInfinitesimal
  2332   monad         <-- cmonad
  2333   galaxy        <-- cgalaxy
  2334   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2335   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2336   (ns)deriv     <-- (ns)cderiv
  2337 
  2338 
  2339 *** HOL-Algebra ***
  2340 
  2341 * Formalisation of ideals and the quotient construction over rings.
  2342 
  2343 * Order and lattice theory no longer based on records.
  2344 INCOMPATIBILITY.
  2345 
  2346 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2347 greatest_closed.  INCOMPATIBILITY.
  2348 
  2349 * Method algebra is now set up via an attribute.  For examples see
  2350 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2351 of algebraic structures.
  2352 
  2353 * Renamed theory CRing to Ring.
  2354 
  2355 
  2356 *** HOL-Nominal ***
  2357 
  2358 * Substantial, yet incomplete support for nominal datatypes (binding
  2359 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2360 src/HOL/Nominal/Examples.  Prospective users should consult
  2361 http://isabelle.in.tum.de/nominal/
  2362 
  2363 
  2364 *** ML ***
  2365 
  2366 * ML basics: just one true type int, which coincides with IntInf.int
  2367 (even on SML/NJ).
  2368 
  2369 * ML within Isar: antiquotations allow to embed statically-checked
  2370 formal entities in the source, referring to the context available at
  2371 compile-time.  For example:
  2372 
  2373 ML {* @{sort "{zero,one}"} *}
  2374 ML {* @{typ "'a => 'b"} *}
  2375 ML {* @{term "%x. x"} *}
  2376 ML {* @{prop "x == y"} *}
  2377 ML {* @{ctyp "'a => 'b"} *}
  2378 ML {* @{cterm "%x. x"} *}
  2379 ML {* @{cprop "x == y"} *}
  2380 ML {* @{thm asm_rl} *}
  2381 ML {* @{thms asm_rl} *}
  2382 ML {* @{type_name c} *}
  2383 ML {* @{type_syntax c} *}
  2384 ML {* @{const_name c} *}
  2385 ML {* @{const_syntax c} *}
  2386 ML {* @{context} *}
  2387 ML {* @{theory} *}
  2388 ML {* @{theory Pure} *}
  2389 ML {* @{theory_ref} *}
  2390 ML {* @{theory_ref Pure} *}
  2391 ML {* @{simpset} *}
  2392 ML {* @{claset} *}
  2393 ML {* @{clasimpset} *}
  2394 
  2395 The same works for sources being ``used'' within an Isar context.
  2396 
  2397 * ML in Isar: improved error reporting; extra verbosity with
  2398 ML_Context.trace enabled.
  2399 
  2400 * Pure/General/table.ML: the join operations now works via exceptions
  2401 DUP/SAME instead of type option. This is simpler in simple cases, and
  2402 admits slightly more efficient complex applications.
  2403 
  2404 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2405 use Context.generic instead of just theory.
  2406 
  2407 * Pure: datatype Context.generic joins theory/Proof.context and
  2408 provides some facilities for code that works in either kind of
  2409 context, notably GenericDataFun for uniform theory and proof data.
  2410 
  2411 * Pure: simplified internal attribute type, which is now always
  2412 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2413 local (Proof.context) attributes have been discontinued, while
  2414 minimizing code duplication. Thm.rule_attribute and
  2415 Thm.declaration_attribute build canonical attributes; see also structure
  2416 Context for further operations on Context.generic, notably
  2417 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2418 declarations and definitions.
  2419 
  2420 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2421 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2422 init only required for impure data. INCOMPATIBILITY: empty really need
  2423 to be empty (no dependencies on theory content!)
  2424 
  2425 * Pure/kernel: consts certification ignores sort constraints given in
  2426 signature declarations. (This information is not relevant to the
  2427 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2428 potential INCOMPATIBILITY.
  2429 
  2430 * Pure: axiomatic type classes are now purely definitional, with
  2431 explicit proofs of class axioms and super class relations performed
  2432 internally. See Pure/axclass.ML for the main internal interfaces --
  2433 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2434 AxClass.axiomatize_class/classrel/arity supersede
  2435 Sign.add_classes/classrel/arities.
  2436 
  2437 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2438 global/local versions on theory vs. Proof.context have been
  2439 discontinued; Attrib.syntax and Method.syntax have been adapted
  2440 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2441 attributes, methods, etc.
  2442 
  2443 * Pure: several functions of signature "... -> theory -> theory * ..."
  2444 have been reoriented to "... -> theory -> ... * theory" in order to
  2445 allow natural usage in combination with the ||>, ||>>, |-> and
  2446 fold_map combinators.
  2447 
  2448 * Pure: official theorem names (closed derivations) and additional
  2449 comments (tags) are now strictly separate.  Name hints -- which are
  2450 maintained as tags -- may be attached any time without affecting the
  2451 derivation.
  2452 
  2453 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2454 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2455 achieve the old behaviour.
  2456 
  2457 * Pure: the "Goal" constant is now called "prop", supporting a
  2458 slightly more general idea of ``protecting'' meta-level rule
  2459 statements.
  2460 
  2461 * Pure: Logic.(un)varify only works in a global context, which is now
  2462 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2463 Logic.legacy_(un)varify as temporary workaround.
  2464 
  2465 * Pure: structure Name provides scalable operations for generating
  2466 internal variable names, notably Name.variants etc.  This replaces
  2467 some popular functions from term.ML:
  2468 
  2469   Term.variant		->  Name.variant
  2470   Term.variantlist	->  Name.variant_list
  2471   Term.invent_names	->  Name.invent_list
  2472 
  2473 Note that low-level renaming rarely occurs in new code -- operations
  2474 from structure Variable are used instead (see below).
  2475 
  2476 * Pure: structure Variable provides fundamental operations for proper
  2477 treatment of fixed/schematic variables in a context.  For example,
  2478 Variable.import introduces fixes for schematics of given facts and
  2479 Variable.export reverses the effect (up to renaming) -- this replaces
  2480 various freeze_thaw operations.
  2481 
  2482 * Pure: structure Goal provides simple interfaces for
  2483 init/conclude/finish and tactical prove operations (replacing former
  2484 Tactic.prove).  Goal.prove is the canonical way to prove results
  2485 within a given context; Goal.prove_global is a degraded version for
  2486 theory level goals, including a global Drule.standard.  Note that
  2487 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2488 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2489 in a locale context).
  2490 
  2491 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2492 and type checking (Syntax.check_term etc.), with common combinations
  2493 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2494 which are considered legacy and await removal.
  2495 
  2496 * Pure/Syntax: generic interfaces for type unchecking
  2497 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2498 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2499 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2500 available for convenience, but refer to the very same operations using
  2501 a mere theory instead of a full context.
  2502 
  2503 * Isar: simplified treatment of user-level errors, using exception
  2504 ERROR of string uniformly.  Function error now merely raises ERROR,
  2505 without any side effect on output channels.  The Isar toplevel takes
  2506 care of proper display of ERROR exceptions.  ML code may use plain
  2507 handle/can/try; cat_error may be used to concatenate errors like this:
  2508 
  2509   ... handle ERROR msg => cat_error msg "..."
  2510 
  2511 Toplevel ML code (run directly or through the Isar toplevel) may be
  2512 embedded into the Isar toplevel with exception display/debug like
  2513 this:
  2514 
  2515   Isar.toplevel (fn () => ...)
  2516 
  2517 INCOMPATIBILITY, removed special transform_error facilities, removed
  2518 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2519 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2520 -- use plain ERROR instead.
  2521 
  2522 * Isar: theory setup now has type (theory -> theory), instead of a
  2523 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2524 
  2525 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2526 ProofContext.debug/verbose flags.
  2527 
  2528 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2529 theory before entering a proof state.  Transactions now always see a
  2530 quasi-functional intermediate checkpoint, both in interactive and
  2531 batch mode.
  2532 
  2533 * Isar: simplified interfaces for outer syntax.  Renamed
  2534 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2535 OuterSyntax.add_parsers -- this functionality is now included in
  2536 OuterSyntax.command etc.  INCOMPATIBILITY.
  2537 
  2538 * Simplifier: the simpset of a running simplification process now
  2539 contains a proof context (cf. Simplifier.the_context), which is the
  2540 very context that the initial simpset has been retrieved from (by
  2541 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2542 (solver, looper etc.) may depend on arbitrary proof data.
  2543 
  2544 * Simplifier.inherit_context inherits the proof context (plus the
  2545 local bounds) of the current simplification process; any simproc
  2546 etc. that calls the Simplifier recursively should do this!  Removed
  2547 former Simplifier.inherit_bounds, which is already included here --
  2548 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2549 specify an explicit context using Simplifier.context/theory_context.
  2550 
  2551 * Simplifier/Classical Reasoner: more abstract interfaces
  2552 change_simpset/claset for modifying the simpset/claset reference of a
  2553 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2554 INCOMPATIBILITY.
  2555 
  2556 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2557 "Trueprop" etc.
  2558 
  2559 
  2560 *** System ***
  2561 
  2562 * settings: the default heap location within ISABELLE_HOME_USER now
  2563 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2564 Isabelle installations.
  2565 
  2566 * isabelle-process: option -S (secure mode) disables some critical
  2567 operations, notably runtime compilation and evaluation of ML source
  2568 code.
  2569 
  2570 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2571 
  2572 * Support for parallel execution, using native multicore support of
  2573 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2574 independent theories, according to the given theory header
  2575 specifications. The maximum number of worker threads is specified via
  2576 usedir option -M or the "max-threads" setting in Proof General. A
  2577 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2578 to 6 on a 8-core machine.  User-code needs to observe certain
  2579 guidelines for thread-safe programming, see appendix A in the Isar
  2580 Implementation manual.
  2581 
  2582 
  2583 
  2584 New in Isabelle2005 (October 2005)
  2585 ----------------------------------
  2586 
  2587 *** General ***
  2588 
  2589 * Theory headers: the new header syntax for Isar theories is
  2590 
  2591   theory <name>
  2592   imports <theory1> ... <theoryN>
  2593   uses <file1> ... <fileM>
  2594   begin
  2595 
  2596 where the 'uses' part is optional.  The previous syntax
  2597 
  2598   theory <name> = <theory1> + ... + <theoryN>:
  2599 
  2600 will disappear in the next release.  Use isatool fixheaders to convert
  2601 existing theory files.  Note that there is no change in ancient
  2602 non-Isar theories now, but these will disappear soon.
  2603 
  2604 * Theory loader: parent theories can now also be referred to via
  2605 relative and absolute paths.
  2606 
  2607 * Command 'find_theorems' searches for a list of criteria instead of a
  2608 list of constants. Known criteria are: intro, elim, dest, name:string,
  2609 simp:term, and any term. Criteria can be preceded by '-' to select
  2610 theorems that do not match. Intro, elim, dest select theorems that
  2611 match the current goal, name:s selects theorems whose fully qualified
  2612 name contain s, and simp:term selects all simplification rules whose
  2613 lhs match term.  Any other term is interpreted as pattern and selects
  2614 all theorems matching the pattern. Available in ProofGeneral under
  2615 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2616 
  2617   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2618 
  2619 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2620 matching the current goal as introduction rule and not having "HOL."
  2621 in their name (i.e. not being defined in theory HOL).
  2622 
  2623 * Command 'thms_containing' has been discontinued in favour of
  2624 'find_theorems'; INCOMPATIBILITY.
  2625 
  2626 * Communication with Proof General is now 8bit clean, which means that
  2627 Unicode text in UTF-8 encoding may be used within theory texts (both
  2628 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2629 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2630 
  2631   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2632   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2633 
  2634 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2635 Classical Reasoner.  Typical big applications run around 2 times
  2636 faster.
  2637 
  2638 
  2639 *** Document preparation ***
  2640 
  2641 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2642 of raw sources.  Only those symbols that do not require additional
  2643 LaTeX packages (depending on comments in isabellesym.sty) are
  2644 displayed properly, everything else is left verbatim.  isatool display
  2645 and isatool print are used as front ends (these are subject to the
  2646 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2647 
  2648 * Command tags control specific markup of certain regions of text,
  2649 notably folding and hiding.  Predefined tags include "theory" (for
  2650 theory begin and end), "proof" for proof commands, and "ML" for
  2651 commands involving ML code; the additional tags "visible" and
  2652 "invisible" are unused by default.  Users may give explicit tag
  2653 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2654 interpretation of tags is determined by the LaTeX job during document
  2655 preparation: see option -V of isatool usedir, or options -n and -t of
  2656 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2657 \isadroptag.
  2658 
  2659 Several document versions may be produced at the same time via isatool
  2660 usedir (the generated index.html will link all of them).  Typical
  2661 specifications include ''-V document=theory,proof,ML'' to present
  2662 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2663 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2664 these parts without any formal replacement text.  The Isabelle site
  2665 default settings produce ''document'' and ''outline'' versions as
  2666 specified above.
  2667 
  2668 * Several new antiquotations:
  2669 
  2670   @{term_type term} prints a term with its type annotated;
  2671 
  2672   @{typeof term} prints the type of a term;
  2673 
  2674   @{const const} is the same as @{term const}, but checks that the
  2675   argument is a known logical constant;
  2676 
  2677   @{term_style style term} and @{thm_style style thm} print a term or
  2678   theorem applying a "style" to it
  2679 
  2680   @{ML text}
  2681 
  2682 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2683 definitions, equations, inequations etc., 'concl' printing only the
  2684 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2685 to print the specified premise.  TermStyle.add_style provides an ML
  2686 interface for introducing further styles.  See also the "LaTeX Sugar"
  2687 document practical applications.  The ML antiquotation prints
  2688 type-checked ML expressions verbatim.
  2689 
  2690 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2691 and 'text' support optional locale specification '(in loc)', which
  2692 specifies the default context for interpreting antiquotations.  For
  2693 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2694 
  2695 * Option 'locale=NAME' of antiquotations specifies an alternative
  2696 context interpreting the subsequent argument.  For example: @{thm
  2697 [locale=lattice] inf_assoc}.
  2698 
  2699 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2700 a proof context.
  2701 
  2702 * Proper output of antiquotations for theory commands involving a
  2703 proof context (such as 'locale' or 'theorem (in loc) ...').
  2704 
  2705 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2706 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2707 
  2708 * isatool usedir: new option -C (default true) controls whether option
  2709 -D should include a copy of the original document directory; -C false
  2710 prevents unwanted effects such as copying of administrative CVS data.
  2711 
  2712 
  2713 *** Pure ***
  2714 
  2715 * Considerably improved version of 'constdefs' command.  Now performs
  2716 automatic type-inference of declared constants; additional support for
  2717 local structure declarations (cf. locales and HOL records), see also
  2718 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2719 sequential dependencies of definitions within a single 'constdefs'
  2720 section; moreover, the declared name needs to be an identifier.  If
  2721 all fails, consider to fall back on 'consts' and 'defs' separately.
  2722 
  2723 * Improved indexed syntax and implicit structures.  First of all,
  2724 indexed syntax provides a notational device for subscripted
  2725 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2726 expressions.  Secondly, in a local context with structure
  2727 declarations, number indexes \<^sub>n or the empty index (default
  2728 number 1) refer to a certain fixed variable implicitly; option
  2729 show_structs controls printing of implicit structures.  Typical
  2730 applications of these concepts involve record types and locales.
  2731 
  2732 * New command 'no_syntax' removes grammar declarations (and
  2733 translations) resulting from the given syntax specification, which is
  2734 interpreted in the same manner as for the 'syntax' command.
  2735 
  2736 * 'Advanced' translation functions (parse_translation etc.) may depend
  2737 on the signature of the theory context being presently used for
  2738 parsing/printing, see also isar-ref manual.
  2739 
  2740 * Improved 'oracle' command provides a type-safe interface to turn an
  2741 ML expression of type theory -> T -> term into a primitive rule of
  2742 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2743 is already included here); see also FOL/ex/IffExample.thy;
  2744 INCOMPATIBILITY.
  2745 
  2746 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2747 before); "cI" is no longer bound, use "c.intro" instead.
  2748 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2749 axclasses vs. locales.
  2750 
  2751 * Improved internal renaming of symbolic identifiers -- attach primes
  2752 instead of base 26 numbers.
  2753 
  2754 * New flag show_question_marks controls printing of leading question
  2755 marks in schematic variable names.
  2756 
  2757 * In schematic variable names, *any* symbol following \<^isub> or
  2758 \<^isup> is now treated as part of the base name.  For example, the
  2759 following works without printing of awkward ".0" indexes:
  2760 
  2761   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2762     by simp
  2763 
  2764 * Inner syntax includes (*(*nested*) comments*).
  2765 
  2766 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2767 annotations as "(00...)".
  2768 
  2769 * Clear separation of logical types and nonterminals, where the latter
  2770 may only occur in 'syntax' specifications or type abbreviations.
  2771 Before that distinction was only partially implemented via type class
  2772 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2773 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2774 exotic syntax specifications may require further adaption
  2775 (e.g. Cube/Cube.thy).
  2776 
  2777 * Removed obsolete type class "logic", use the top sort {} instead.
  2778 Note that non-logical types should be declared as 'nonterminals'
  2779 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2780 specifications.
  2781 
  2782 * Attributes 'induct' and 'cases': type or set names may now be
  2783 locally fixed variables as well.
  2784 
  2785 * Simplifier: can now control the depth to which conditional rewriting
  2786 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2787 Limit.
  2788 
  2789 * Simplifier: simplification procedures may now take the current
  2790 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2791 interface), which is very useful for calling the Simplifier
  2792 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2793 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2794 low-level mk_simproc no longer applies Logic.varify internally, to
  2795 allow for use in a context of fixed variables.
  2796 
  2797 * thin_tac now works even if the assumption being deleted contains !!
  2798 or ==>.  More generally, erule now works even if the major premise of
  2799 the elimination rule contains !! or ==>.
  2800 
  2801 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2802 
  2803 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2804 from Pure, which contains all common declarations already.  Both
  2805 theories are defined via plain Isabelle/Isar .thy files.
  2806 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2807 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2808 use isatool fixcpure to adapt your theory and ML sources.
  2809 
  2810 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2811 selections of theorems in named facts via index ranges.
  2812 
  2813 * 'print_theorems': in theory mode, really print the difference
  2814 wrt. the last state (works for interactive theory development only),
  2815 in proof mode print all local facts (cf. 'print_facts');
  2816 
  2817 * 'hide': option '(open)' hides only base names.
  2818 
  2819 * More efficient treatment of intermediate checkpoints in interactive
  2820 theory development.
  2821 
  2822 * Code generator is now invoked via code_module (incremental code
  2823 generation) and code_library (modular code generation, ML structures
  2824 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2825 must be quoted when used as identifiers.
  2826 
  2827 * New 'value' command for reading, evaluating and printing terms using
  2828 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2829 quoted when used as identifier.
  2830 
  2831 
  2832 *** Locales ***
  2833 
  2834 * New commands for the interpretation of locale expressions in
  2835 theories (1), locales (2) and proof contexts (3).  These generate
  2836 proof obligations from the expression specification.  After the
  2837 obligations have been discharged, theorems of the expression are added
  2838 to the theory, target locale or proof context.  The synopsis of the
  2839 commands is a follows:
  2840 
  2841   (1) interpretation expr inst
  2842   (2) interpretation target < expr
  2843   (3) interpret expr inst
  2844 
  2845 Interpretation in theories and proof contexts require a parameter
  2846 instantiation of terms from the current context.  This is applied to
  2847 specifications and theorems of the interpreted expression.
  2848 Interpretation in locales only permits parameter renaming through the
  2849 locale expression.  Interpretation is smart in that interpretations
  2850 that are active already do not occur in proof obligations, neither are
  2851 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2852 inspect active interpretations of a particular locale.  For details,
  2853 see the Isar Reference manual.  Examples can be found in
  2854 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2855 
  2856 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2857 'interpret' instead.
  2858 
  2859 * New context element 'constrains' for adding type constraints to
  2860 parameters.
  2861 
  2862 * Context expressions: renaming of parameters with syntax
  2863 redeclaration.
  2864 
  2865 * Locale declaration: 'includes' disallowed.
  2866 
  2867 * Proper static binding of attribute syntax -- i.e. types / terms /
  2868 facts mentioned as arguments are always those of the locale definition
  2869 context, independently of the context of later invocations.  Moreover,
  2870 locale operations (renaming and type / term instantiation) are applied
  2871 to attribute arguments as expected.
  2872 
  2873 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2874 actual attributes; rare situations may require Attrib.attribute to
  2875 embed those attributes into Attrib.src that lack concrete syntax.
  2876 Attribute implementations need to cooperate properly with the static
  2877 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2878 Attrib.XXX_thm etc. already do the right thing without further
  2879 intervention.  Only unusual applications -- such as "where" or "of"
  2880 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2881 on the context and the facts involved -- may have to assign parsed
  2882 values to argument tokens explicitly.
  2883 
  2884 * Changed parameter management in theorem generation for long goal
  2885 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2886 theorem statement in rare situations.
  2887 
  2888 * Locale inspection command 'print_locale' omits notes elements.  Use
  2889 'print_locale!' to have them included in the output.
  2890 
  2891 
  2892 *** Provers ***
  2893 
  2894 * Provers/hypsubst.ML: improved version of the subst method, for
  2895 single-step rewriting: it now works in bound variable contexts. New is
  2896 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2897 rewrite a different subterm than the original subst method, which is
  2898 still available as 'simplesubst'.
  2899 
  2900 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2901 and quasi orders.
  2902 
  2903 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2904 reflexive-transitive closure of relations.
  2905 
  2906 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2907 limit (previously hard-coded with a value of 20) user-definable.
  2908 
  2909 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2910 is peformed already.  Object-logics merely need to finish their
  2911 initial simpset configuration as before.  INCOMPATIBILITY.
  2912 
  2913 
  2914 *** HOL ***
  2915 
  2916 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2917 
  2918   syntax (epsilon)
  2919     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2920 
  2921 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2922 and x-symbol; use option '-m epsilon' to get it actually printed.
  2923 Moreover, the mathematically important symbolic identifier \<epsilon>
  2924 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2925 
  2926 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2927 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2928 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2929 support corresponding Isar calculations.
  2930 
  2931 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2932 instead of ":".
  2933 
  2934 * theory SetInterval: changed the syntax for open intervals:
  2935 
  2936   Old       New
  2937   {..n(}    {..<n}
  2938   {)n..}    {n<..}
  2939   {m..n(}   {m..<n}
  2940   {)m..n}   {m<..n}
  2941   {)m..n(}  {m<..<n}
  2942 
  2943 The old syntax is still supported but will disappear in the next
  2944 release.  For conversion use the following Emacs search and replace
  2945 patterns (these are not perfect but work quite well):
  2946 
  2947   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2948   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2949 
  2950 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2951 equalities in commutative rings; method 'algebra' provides a generic
  2952 interface.
  2953 
  2954 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2955 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2956 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2957 be a tuple pattern.
  2958 
  2959 Some new syntax forms are available:
  2960 
  2961   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2962   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2963   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2964   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2965 
  2966 The latter form "\<Sum>x < k. e" used to be based on a separate
  2967 function "Summation", which has been discontinued.
  2968 
  2969 * theory Finite_Set: in structured induction proofs, the insert case
  2970 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2971 (insert F x)'.
  2972 
  2973 * The 'refute' command has been extended to support a much larger
  2974 fragment of HOL, including axiomatic type classes, constdefs and
  2975 typedefs, inductive datatypes and recursion.
  2976 
  2977 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2978 Requires zChaff with proof generation to be installed.  See
  2979 HOL/ex/SAT_Examples.thy for examples.
  2980 
  2981 * Datatype induction via method 'induct' now preserves the name of the
  2982 induction variable. For example, when proving P(xs::'a list) by
  2983 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2984 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2985 in unstructured proof scripts.
  2986 
  2987 * Reworked implementation of records.  Improved scalability for
  2988 records with many fields, avoiding performance problems for type
  2989 inference. Records are no longer composed of nested field types, but
  2990 of nested extension types. Therefore the record type only grows linear
  2991 in the number of extensions and not in the number of fields.  The
  2992 top-level (users) view on records is preserved.  Potential
  2993 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2994 old record representation. The type generated for a record is called
  2995 <record_name>_ext_type.
  2996 
  2997 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2998 proofs triggered by a record definition or a simproc (if
  2999 quick_and_dirty is enabled).  Definitions of large records can take
  3000 quite long.
  3001 
  3002 New simproc record_upd_simproc for simplification of multiple record
  3003 updates enabled by default.  Moreover, trivial updates are also
  3004 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3005 occasionally, since simplification is more powerful by default.
  3006 
  3007 * typedef: proper support for polymorphic sets, which contain extra
  3008 type-variables in the term.
  3009 
  3010 * Simplifier: automatically reasons about transitivity chains
  3011 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3012 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3013 old proofs break occasionally as simplification may now solve more
  3014 goals than previously.
  3015 
  3016 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3017 present.  Works for all partial orders (class "order"), in particular
  3018 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3019 just like y <= x.
  3020 
  3021 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3022 bound variable or a constant then the let is unfolded.  Otherwise
  3023 first a is simplified to b, and then f b is simplified to g. If
  3024 possible we abstract b from g arriving at "let x = b in h x",
  3025 otherwise we unfold the let and arrive at g.  The simproc can be
  3026 enabled/disabled by the reference use_let_simproc.  Potential
  3027 INCOMPATIBILITY since simplification is more powerful by default.
  3028 
  3029 * Classical reasoning: the meson method now accepts theorems as arguments.
  3030 
  3031 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3032 jobs to provide advice on the provability of subgoals.
  3033 
  3034 * Theory OrderedGroup and Ring_and_Field: various additions and
  3035 improvements to faciliate calculations involving equalities and
  3036 inequalities.
  3037 
  3038 The following theorems have been eliminated or modified
  3039 (INCOMPATIBILITY):
  3040 
  3041   abs_eq             now named abs_of_nonneg
  3042   abs_of_ge_0        now named abs_of_nonneg
  3043   abs_minus_eq       now named abs_of_nonpos
  3044   imp_abs_id         now named abs_of_nonneg
  3045   imp_abs_neg_id     now named abs_of_nonpos
  3046   mult_pos           now named mult_pos_pos
  3047   mult_pos_le        now named mult_nonneg_nonneg
  3048   mult_pos_neg_le    now named mult_nonneg_nonpos
  3049   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3050   mult_neg           now named mult_neg_neg
  3051   mult_neg_le        now named mult_nonpos_nonpos
  3052 
  3053 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3054      
  3055      zero_le_square
  3056      not_square_less_zero 
  3057 
  3058   The following lemmas have been deleted from Real/RealPow:
  3059   
  3060      realpow_zero_zero
  3061      realpow_two
  3062      realpow_less
  3063      zero_le_power
  3064      realpow_two_le
  3065      abs_realpow_two
  3066      realpow_two_abs     
  3067 
  3068 * Theory Parity: added rules for simplifying exponents.
  3069 
  3070 * Theory List:
  3071 
  3072 The following theorems have been eliminated or modified
  3073 (INCOMPATIBILITY):
  3074 
  3075   list_all_Nil       now named list_all.simps(1)
  3076   list_all_Cons      now named list_all.simps(2)
  3077   list_all_conv      now named list_all_iff
  3078   set_mem_eq         now named mem_iff
  3079 
  3080 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3081 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3082 
  3083 
  3084 *** HOL-Complex ***
  3085 
  3086 * Theory RealDef: better support for embedding natural numbers and
  3087 integers in the reals.
  3088 
  3089 The following theorems have been eliminated or modified
  3090 (INCOMPATIBILITY):
  3091 
  3092   exp_ge_add_one_self  now requires no hypotheses
  3093   real_of_int_add      reversed direction of equality (use [symmetric])
  3094   real_of_int_minus    reversed direction of equality (use [symmetric])
  3095   real_of_int_diff     reversed direction of equality (use [symmetric])
  3096   real_of_int_mult     reversed direction of equality (use [symmetric])
  3097 
  3098 * Theory RComplete: expanded support for floor and ceiling functions.
  3099 
  3100 * Theory Ln is new, with properties of the natural logarithm
  3101 
  3102 * Hyperreal: There is a new type constructor "star" for making
  3103 nonstandard types.  The old type names are now type synonyms:
  3104 
  3105   hypreal = real star
  3106   hypnat = nat star
  3107   hcomplex = complex star
  3108 
  3109 * Hyperreal: Many groups of similarly-defined constants have been
  3110 replaced by polymorphic versions (INCOMPATIBILITY):
  3111 
  3112   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3113 
  3114   starset      <-- starsetNat, starsetC
  3115   *s*          <-- *sNat*, *sc*
  3116   starset_n    <-- starsetNat_n, starsetC_n
  3117   *sn*         <-- *sNatn*, *scn*
  3118   InternalSets <-- InternalNatSets, InternalCSets
  3119 
  3120   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3121   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3122   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3123   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3124   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3125 
  3126 * Hyperreal: Many type-specific theorems have been removed in favor of
  3127 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3128 
  3129   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3130   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3131   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3132   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3133   right_minus <-- hypreal_add_minus
  3134   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3135   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3136   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3137   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3138   mult_1_right <-- hcomplex_mult_one_right
  3139   mult_zero_left <-- hcomplex_mult_zero_left
  3140   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3141   right_distrib <-- hypnat_add_mult_distrib2
  3142   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3143   right_inverse <-- hypreal_mult_inverse
  3144   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3145   order_refl <-- {hypreal,hypnat}_le_refl
  3146   order_trans <-- {hypreal,hypnat}_le_trans
  3147   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3148   order_less_le <-- {hypreal,hypnat}_less_le
  3149   linorder_linear <-- {hypreal,hypnat}_le_linear
  3150   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3151   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3152   add_nonneg_nonneg <-- hypreal_le_add_order
  3153 
  3154 * Hyperreal: Separate theorems having to do with type-specific
  3155 versions of constants have been merged into theorems that apply to the
  3156 new polymorphic constants (INCOMPATIBILITY):
  3157 
  3158   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3159   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3160   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3161   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3162   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3163   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3164   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3165   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3166   STAR_diff <-- {STAR,STARC}_diff
  3167   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3168     STARC_hcomplex_of_complex}_image_subset
  3169   starset_n_Un <-- starset{Nat,C}_n_Un
  3170   starset_n_Int <-- starset{Nat,C}_n_Int
  3171   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3172   starset_n_diff <-- starset{Nat,C}_n_diff
  3173   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3174   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3175   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3176   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3177   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3178   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3179   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3180   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3181   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3182   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3183   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3184   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3185   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3186   starfun_diff <-- starfun{C,RC,CR}_diff
  3187   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3188   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3189   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3190   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3191   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3192   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3193   starfun_Id <-- starfunC_Id
  3194   starfun_approx <-- starfun{Nat,CR}_approx
  3195   starfun_capprox <-- starfun{C,RC}_capprox
  3196   starfun_abs <-- starfunNat_rabs
  3197   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3198   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3199   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3200   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3201   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3202   starfun_add_approx <-- starfunCR_add_approx
  3203   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3204   starfun_divide <-- starfun{C,CR,RC}_divide
  3205   starfun_n <-- starfun{Nat,C}_n
  3206   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3207   starfun_n_add <-- starfun{Nat,C}_n_add
  3208   starfun_n_add_minus <-- starfunNat_n_add_minus
  3209   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3210   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3211   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3212 
  3213   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3214   star_n_minus <-- {hypreal,hcomplex}_minus
  3215   star_n_diff <-- {hypreal,hcomplex}_diff
  3216   star_n_mult <-- {hypreal,hcomplex}_mult
  3217   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3218   star_n_le <-- {hypreal,hypnat}_le
  3219   star_n_less <-- {hypreal,hypnat}_less
  3220   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3221   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3222   star_n_abs <-- hypreal_hrabs
  3223   star_n_divide <-- hcomplex_divide
  3224 
  3225   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3226   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3227   star_of_diff <-- hypreal_of_real_diff
  3228   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3229   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3230   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3231   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3232   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3233   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3234   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3235   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3236   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3237   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3238   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3239   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3240   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3241   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3242   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3243   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3244   star_of_power <-- hypreal_of_real_power
  3245   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3246 
  3247 * Hyperreal: new method "transfer" that implements the transfer
  3248 principle of nonstandard analysis. With a subgoal that mentions
  3249 nonstandard types like "'a star", the command "apply transfer"
  3250 replaces it with an equivalent one that mentions only standard types.
  3251 To be successful, all free variables must have standard types; non-
  3252 standard variables must have explicit universal quantifiers.
  3253 
  3254 * Hyperreal: A theory of Taylor series.
  3255 
  3256 
  3257 *** HOLCF ***
  3258 
  3259 * Discontinued special version of 'constdefs' (which used to support
  3260 continuous functions) in favor of the general Pure one with full
  3261 type-inference.
  3262 
  3263 * New simplification procedure for solving continuity conditions; it
  3264 is much faster on terms with many nested lambda abstractions (cubic
  3265 instead of exponential time).
  3266 
  3267 * New syntax for domain package: selector names are now optional.
  3268 Parentheses should be omitted unless argument is lazy, for example:
  3269 
  3270   domain 'a stream = cons "'a" (lazy "'a stream")
  3271 
  3272 * New command 'fixrec' for defining recursive functions with pattern
  3273 matching; defining multiple functions with mutual recursion is also
  3274 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3275 sinr, or any data constructor defined by the domain package. The given
  3276 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3277 syntax and examples.
  3278 
  3279 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3280 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3281 but the proof obligation additionally includes an admissibility
  3282 requirement. The packages generate instances of class cpo or pcpo,
  3283 with continuity and strictness theorems for Rep and Abs.
  3284 
  3285 * HOLCF: Many theorems have been renamed according to a more standard naming
  3286 scheme (INCOMPATIBILITY):
  3287 
  3288   foo_inject:  "foo$x = foo$y ==> x = y"
  3289   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3290   foo_less:    "(foo$x << foo$y) = (x << y)"
  3291   foo_strict:  "foo$UU = UU"
  3292   foo_defined: "... ==> foo$x ~= UU"
  3293   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3294 
  3295 
  3296 *** ZF ***
  3297 
  3298 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3299 including the First Isomorphism Theorem (on quotienting by the kernel
  3300 of a homomorphism).
  3301 
  3302 * ZF/Simplifier: install second copy of type solver that actually
  3303 makes use of TC rules declared to Isar proof contexts (or locales);
  3304 the old version is still required for ML proof scripts.
  3305 
  3306 
  3307 *** Cube ***
  3308 
  3309 * Converted to Isar theory format; use locales instead of axiomatic
  3310 theories.
  3311 
  3312 
  3313 *** ML ***
  3314 
  3315 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3316 for ||>, ||>>, |>>,
  3317 
  3318 * Pure/library.ML no longer defines its own option datatype, but uses
  3319 that of the SML basis, which has constructors NONE and SOME instead of
  3320 None and Some, as well as exception Option.Option instead of OPTION.
  3321 The functions the, if_none, is_some, is_none have been adapted
  3322 accordingly, while Option.map replaces apsome.
  3323 
  3324 * Pure/library.ML: the exception LIST has been given up in favour of
  3325 the standard exceptions Empty and Subscript, as well as
  3326 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3327 superceded by the standard hd and tl functions etc.
  3328 
  3329 A number of basic list functions are no longer exported to the ML
  3330 toplevel, as they are variants of predefined functions.  The following
  3331 suggests how one can translate existing code:
  3332 
  3333     rev_append xs ys = List.revAppend (xs, ys)
  3334     nth_elem (i, xs) = List.nth (xs, i)
  3335     last_elem xs = List.last xs
  3336     flat xss = List.concat xss
  3337     seq fs = List.app fs
  3338     partition P xs = List.partition P xs
  3339     mapfilter f xs = List.mapPartial f xs
  3340 
  3341 * Pure/library.ML: several combinators for linear functional
  3342 transformations, notably reverse application and composition:
  3343 
  3344   x |> f                f #> g
  3345   (x, y) |-> f          f #-> g
  3346 
  3347 * Pure/library.ML: introduced/changed precedence of infix operators:
  3348 
  3349   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3350   infix 2 ?;
  3351   infix 3 o oo ooo oooo;
  3352   infix 4 ~~ upto downto;
  3353 
  3354 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3355 infix operators.
  3356 
  3357 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3358 fold_map support linear functional transformations and nesting.  For
  3359 example:
  3360 
  3361   fold f [x1, ..., xN] y =
  3362     y |> f x1 |> ... |> f xN
  3363 
  3364   (fold o fold) f [xs1, ..., xsN] y =
  3365     y |> fold f xs1 |> ... |> fold f xsN
  3366 
  3367   fold f [x1, ..., xN] =
  3368     f x1 #> ... #> f xN
  3369 
  3370   (fold o fold) f [xs1, ..., xsN] =
  3371     fold f xs1 #> ... #> fold f xsN
  3372 
  3373 * Pure/library.ML: the following selectors on type 'a option are
  3374 available:
  3375 
  3376   the:               'a option -> 'a  (*partial*)
  3377   these:             'a option -> 'a  where 'a = 'b list
  3378   the_default: 'a -> 'a option -> 'a
  3379   the_list:          'a option -> 'a list
  3380 
  3381 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3382 basic operations for association lists, following natural argument
  3383 order; moreover the explicit equality predicate passed here avoids
  3384 potentially expensive polymorphic runtime equality checks.
  3385 The old functions may be expressed as follows:
  3386 
  3387   assoc = uncurry (AList.lookup (op =))
  3388   assocs = these oo AList.lookup (op =)
  3389   overwrite = uncurry (AList.update (op =)) o swap
  3390 
  3391 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3392 
  3393   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3394   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3395 
  3396 replacing make_keylist and keyfilter (occassionally used)
  3397 Naive rewrites:
  3398 
  3399   make_keylist = AList.make
  3400   keyfilter = AList.find (op =)
  3401 
  3402 * eq_fst and eq_snd now take explicit equality parameter, thus
  3403   avoiding eqtypes. Naive rewrites:
  3404 
  3405     eq_fst = eq_fst (op =)
  3406     eq_snd = eq_snd (op =)
  3407 
  3408 * Removed deprecated apl and apr (rarely used).
  3409   Naive rewrites:
  3410 
  3411     apl (n, op) =>>= curry op n
  3412     apr (op, m) =>>= fn n => op (n, m)
  3413 
  3414 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3415 provides a reasonably efficient light-weight implementation of sets as
  3416 lists.
  3417 
  3418 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3419 few new operations; existing lookup and update are now curried to
  3420 follow natural argument order (for use with fold etc.);
  3421 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3422 
  3423 * Pure/General: output via the Isabelle channels of
  3424 writeln/warning/error etc. is now passed through Output.output, with a
  3425 hook for arbitrary transformations depending on the print_mode
  3426 (cf. Output.add_mode -- the first active mode that provides a output
  3427 function wins).  Already formatted output may be embedded into further
  3428 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3429 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3430 accommodate easy composition of diagnostic messages etc.  Programmers
  3431 rarely need to care about Output.output or Output.raw at all, with
  3432 some notable exceptions: Output.output is required when bypassing the
  3433 standard channels (writeln etc.), or in token translations to produce
  3434 properly formatted results; Output.raw is required when capturing
  3435 already output material that will eventually be presented to the user
  3436 a second time.  For the default print mode, both Output.output and
  3437 Output.raw have no effect.
  3438 
  3439 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3440 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3441 cumulative results are displayed at the end of a batch session.
  3442 
  3443 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3444 replaced by File.platform_path and File.shell_path (with appropriate
  3445 hooks).  This provides a clean interface for unusual systems where the
  3446 internal and external process view of file names are different.
  3447 
  3448 * Pure: more efficient orders for basic syntactic entities: added
  3449 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3450 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3451 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3452 orders now -- potential INCOMPATIBILITY for code that depends on a
  3453 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3454 Library.sort_strings on result).
  3455 
  3456 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3457 fold_types traverse types/terms from left to right, observing natural
  3458 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3459 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3460 
  3461 * Pure: name spaces have been refined, with significant changes of the
  3462 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3463 to extern(_table).  The plain name entry path is superceded by a
  3464 general 'naming' context, which also includes the 'policy' to produce
  3465 a fully qualified name and external accesses of a fully qualified
  3466 name; NameSpace.extend is superceded by context dependent
  3467 Sign.declare_name.  Several theory and proof context operations modify
  3468 the naming context.  Especially note Theory.restore_naming and
  3469 ProofContext.restore_naming to get back to a sane state; note that
  3470 Theory.add_path is no longer sufficient to recover from
  3471 Theory.absolute_path in particular.
  3472 
  3473 * Pure: new flags short_names (default false) and unique_names
  3474 (default true) for controlling output of qualified names.  If
  3475 short_names is set, names are printed unqualified.  If unique_names is
  3476 reset, the name prefix is reduced to the minimum required to achieve
  3477 the original result when interning again, even if there is an overlap
  3478 with earlier declarations.
  3479 
  3480 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3481 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3482 (useful for printing error messages).  INCOMPATIBILITY.
  3483 
  3484 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3485 Theory.theory are now identified, referring to the universal
  3486 Context.theory (see Pure/context.ML).  Actual signature and theory
  3487 content is managed as theory data.  The old code and interfaces were
  3488 spread over many files and structures; the new arrangement introduces
  3489 considerable INCOMPATIBILITY to gain more clarity:
  3490 
  3491   Context -- theory management operations (name, identity, inclusion,
  3492     parents, ancestors, merge, etc.), plus generic theory data;
  3493 
  3494   Sign -- logical signature and syntax operations (declaring consts,
  3495     types, etc.), plus certify/read for common entities;
  3496 
  3497   Theory -- logical theory operations (stating axioms, definitions,
  3498     oracles), plus a copy of logical signature operations (consts,
  3499     types, etc.); also a few basic management operations (Theory.copy,
  3500     Theory.merge, etc.)
  3501 
  3502 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3503 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3504 for convenience -- they merely return the theory.
  3505 
  3506 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3507 
  3508 * Pure: the Isar proof context type is already defined early in Pure
  3509 as Context.proof (note that ProofContext.context and Proof.context are
  3510 aliases, where the latter is the preferred name).  This enables other
  3511 Isabelle components to refer to that type even before Isar is present.
  3512 
  3513 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3514 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3515 any of these kinds.  For example, Sign.intern typeK is now
  3516 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3517 Theory.hide_types.  Also note that former
  3518 Theory.hide_classes/types/consts are now
  3519 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3520 internalize their arguments!  INCOMPATIBILITY.
  3521 
  3522 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3523 datatype thmref (with constructors Name and NameSelection) instead of
  3524 plain string -- INCOMPATIBILITY;
  3525 
  3526 * Pure: cases produced by proof methods specify options, where NONE
  3527 means to remove case bindings -- INCOMPATIBILITY in
  3528 (RAW_)METHOD_CASES.
  3529 
  3530 * Pure: the following operations retrieve axioms or theorems from a
  3531 theory node or theory hierarchy, respectively:
  3532 
  3533   Theory.axioms_of: theory -> (string * term) list
  3534   Theory.all_axioms_of: theory -> (string * term) list
  3535   PureThy.thms_of: theory -> (string * thm) list
  3536   PureThy.all_thms_of: theory -> (string * thm) list
  3537 
  3538 * Pure: print_tac now outputs the goal through the trace channel.
  3539 
  3540 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3541 Reference Toplevel.debug (default false) controls detailed printing
  3542 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3543 controls execution profiling -- set to 1 for time and 2 for space
  3544 (both increase the runtime).
  3545 
  3546 * Isar session: The initial use of ROOT.ML is now always timed,
  3547 i.e. the log will show the actual process times, in contrast to the
  3548 elapsed wall-clock time that the outer shell wrapper produces.
  3549 
  3550 * Simplifier: improved handling of bound variables (nameless
  3551 representation, avoid allocating new strings).  Simprocs that invoke
  3552 the Simplifier recursively should use Simplifier.inherit_bounds to
  3553 avoid local name clashes.  Failure to do so produces warnings
  3554 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3555 for further details.
  3556 
  3557 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3558 bindings for all theorems stored within a given theory; this may help
  3559 in porting non-Isar theories to Isar ones, while keeping ML proof
  3560 scripts for the time being.
  3561 
  3562 * ML operator HTML.with_charset specifies the charset begin used for
  3563 generated HTML files.  For example:
  3564 
  3565   HTML.with_charset "utf-8" use_thy "Hebrew";
  3566   HTML.with_charset "utf-8" use_thy "Chinese";
  3567 
  3568 
  3569 *** System ***
  3570 
  3571 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3572 isabelle, isatool etc.).
  3573 
  3574 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3575 isatool doc, isatool mkdir, display_drafts etc.).
  3576 
  3577 * isatool usedir: option -f allows specification of the ML file to be
  3578 used by Isabelle; default is ROOT.ML.
  3579 
  3580 * New isatool version outputs the version identifier of the Isabelle
  3581 distribution being used.
  3582 
  3583 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3584 (containing Boolean satisfiability problems) into Isabelle/HOL
  3585 theories.
  3586 
  3587 
  3588 
  3589 New in Isabelle2004 (April 2004)
  3590 --------------------------------
  3591 
  3592 *** General ***
  3593 
  3594 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3595   Replaces linorder.ML.
  3596 
  3597 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3598   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3599   (\<a>...\<z>), are now considered normal letters, and can therefore
  3600   be used anywhere where an ASCII letter (a...zA...Z) has until
  3601   now. COMPATIBILITY: This obviously changes the parsing of some
  3602   terms, especially where a symbol has been used as a binder, say
  3603   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3604   as an identifier.  Fix it by inserting a space around former
  3605   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3606   existing theory and ML files.
  3607 
  3608 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3609 
  3610 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3611   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3612   a normal (but invisible) letter. For multiple letter subscripts repeat
  3613   \<^isub> like this: x\<^isub>1\<^isub>2.
  3614 
  3615 * Pure: There are now sub-/superscripts that can span more than one
  3616   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3617   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3618   superscript. The new control characters are not identifier parts.
  3619 
  3620 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3621   content of "..." to the latex file instead of \isacntrl... . The "..."
  3622   may consist of any printable characters excluding the end bracket >.
  3623 
  3624 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3625   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3626   declare constants "final", which prevents their being given a definition
  3627   later.  It is useful for constants whose behaviour is fixed axiomatically
  3628   rather than definitionally, such as the meta-logic connectives.
  3629 
  3630 * Pure: 'instance' now handles general arities with general sorts
  3631   (i.e. intersections of classes),
  3632 
  3633 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3634   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3635   It can be changed to alter the colors/layout of generated pages.
  3636 
  3637 
  3638 *** Isar ***
  3639 
  3640 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3641   cut_tac, subgoal_tac and thin_tac:
  3642   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3643     locales are no longer forced to write Isar proof scripts.
  3644     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3645     emulations.
  3646   - INCOMPATIBILITY: names of variables to be instantiated may no
  3647     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3648     This is consistent with the instantiation attribute "where".
  3649 
  3650 * Attributes "where" and "of":
  3651   - Now take type variables of instantiated theorem into account when reading
  3652     the instantiation string.  This fixes a bug that caused instantiated
  3653     theorems to have too special types in some circumstances.
  3654   - "where" permits explicit instantiations of type variables.
  3655 
  3656 * Calculation commands "moreover" and "also" no longer interfere with
  3657   current facts ("this"), admitting arbitrary combinations with "then"
  3658   and derived forms.
  3659 
  3660 * Locales:
  3661   - Goal statements involving the context element "includes" no longer
  3662     generate theorems with internal delta predicates (those ending on
  3663     "_axioms") in the premise.
  3664     Resolve particular premise with <locale>.intro to obtain old form.
  3665   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3666     specification and "includes" elements in goal statement.
  3667   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3668     [intro?] and [elim?] (respectively) by default.
  3669   - Experimental command for instantiation of locales in proof contexts:
  3670         instantiate <label>[<attrs>]: <loc>
  3671     Instantiates locale <loc> and adds all its theorems to the current context
  3672     taking into account their attributes.  Label and attrs are optional
  3673     modifiers, like in theorem declarations.  If present, names of
  3674     instantiated theorems are qualified with <label>, and the attributes
  3675     <attrs> are applied after any attributes these theorems might have already.
  3676       If the locale has assumptions, a chained fact of the form
  3677     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3678     are derived.  The command does not support old-style locales declared
  3679     with "locale (open)".
  3680       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3681 
  3682 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3683   (Isar) contexts.
  3684 
  3685 
  3686 *** HOL ***
  3687 
  3688 * Proof import: new image HOL4 contains the imported library from
  3689   the HOL4 system with about 2500 theorems. It is imported by
  3690   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3691   can be used like any other Isabelle image.  See
  3692   HOL/Import/HOL/README for more information.
  3693 
  3694 * Simplifier:
  3695   - Much improved handling of linear and partial orders.
  3696     Reasoners for linear and partial orders are set up for type classes
  3697     "linorder" and "order" respectively, and are added to the default simpset
  3698     as solvers.  This means that the simplifier can build transitivity chains
  3699     to solve goals from the assumptions.
  3700   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3701     of blast or auto after simplification become unnecessary because the goal
  3702     is solved by simplification already.
  3703 
  3704 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3705     all proved in axiomatic type classes for semirings, rings and fields.
  3706 
  3707 * Numerics:
  3708   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3709     now formalized using the Ring_and_Field theory mentioned above.
  3710   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3711     than before, because now they are set up once in a generic manner.
  3712   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3713     Look for the general versions in Ring_and_Field (and Power if they concern
  3714     exponentiation).
  3715 
  3716 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3717 
  3718 * Records:
  3719   - Record types are now by default printed with their type abbreviation
  3720     instead of the list of all field types. This can be configured via
  3721     the reference "print_record_type_abbr".
  3722   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3723     (not enabled by default).
  3724   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3725     EX x. x = sel r to True (not enabled by default).
  3726   - Tactic "record_split_simp_tac" to split and simplify records added.
  3727 
  3728 * 'specification' command added, allowing for definition by
  3729   specification.  There is also an 'ax_specification' command that
  3730   introduces the new constants axiomatically.
  3731 
  3732 * arith(_tac) is now able to generate counterexamples for reals as well.
  3733 
  3734 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3735 
  3736 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3737   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3738 
  3739 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3740   matrix theory to linear programming.
  3741 
  3742 * Unions and Intersections:
  3743   The latex output syntax of UN and INT has been changed
  3744   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3745   i.e. the index formulae has become a subscript.
  3746   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3747 
  3748 * Unions and Intersections over Intervals:
  3749   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3750   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3751   like in normal math, and corresponding versions for < and for intersection.
  3752 
  3753 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3754   lexicographic dictonary ordering has been added as "lexord".
  3755 
  3756 * ML: the legacy theory structures Int and List have been removed. They had
  3757   conflicted with ML Basis Library structures having the same names.
  3758 
  3759 * 'refute' command added to search for (finite) countermodels.  Only works
  3760   for a fragment of HOL.  The installation of an external SAT solver is
  3761   highly recommended.  See "HOL/Refute.thy" for details.
  3762 
  3763 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3764   formulae under an assignment of free variables to random values.
  3765   In contrast to 'refute', it can deal with inductive datatypes,
  3766   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3767   for examples.
  3768 
  3769 
  3770 *** HOLCF ***
  3771 
  3772 * Streams now come with concatenation and are part of the HOLCF image
  3773 
  3774 
  3775 
  3776 New in Isabelle2003 (May 2003)
  3777 ------------------------------
  3778 
  3779 *** General ***
  3780 
  3781 * Provers/simplifier:
  3782 
  3783   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3784     Assumptions are now subject to complete mutual simplification,
  3785     not just from left to right. The simplifier now preserves
  3786     the order of assumptions.
  3787 
  3788     Potential INCOMPATIBILITY:
  3789 
  3790     -- simp sometimes diverges where the old version did
  3791        not, e.g. invoking simp on the goal
  3792 
  3793         [| P (f x); y = x; f x = f y |] ==> Q
  3794 
  3795        now gives rise to the infinite reduction sequence
  3796 
  3797         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3798 
  3799        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3800        kind of problem.
  3801 
  3802     -- Tactics combining classical reasoner and simplification (such as auto)
  3803        are also affected by this change, because many of them rely on
  3804        simp. They may sometimes diverge as well or yield a different numbers
  3805        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3806        in case of problems. Sometimes subsequent calls to the classical
  3807        reasoner will fail because a preceeding call to the simplifier too
  3808        eagerly simplified the goal, e.g. deleted redundant premises.
  3809 
  3810   - The simplifier trace now shows the names of the applied rewrite rules
  3811 
  3812   - You can limit the number of recursive invocations of the simplifier
  3813     during conditional rewriting (where the simplifie tries to solve the
  3814     conditions before applying the rewrite rule):
  3815     ML "simp_depth_limit := n"
  3816     where n is an integer. Thus you can force termination where previously
  3817     the simplifier would diverge.
  3818 
  3819   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3820 
  3821   - No longer aborts on failed congruence proof.  Instead, the
  3822     congruence is ignored.
  3823 
  3824 * Pure: New generic framework for extracting programs from constructive
  3825   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3826   as HOL/Extraction for some case studies.
  3827 
  3828 * Pure: The main goal of the proof state is no longer shown by default, only
  3829 the subgoals. This behaviour is controlled by a new flag.
  3830    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3831 (ML: Proof.show_main_goal).
  3832 
  3833 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3834 rules whose conclusion matches subgoal 1:
  3835       PG menu: Isabelle/Isar -> Show me -> matching rules
  3836 The rules are ordered by how closely they match the subgoal.
  3837 In particular, rules that solve a subgoal outright are displayed first
  3838 (or rather last, the way they are printed).
  3839 (ML: ProofGeneral.print_intros())
  3840 
  3841 * Pure: New flag trace_unify_fail causes unification to print
  3842 diagnostic information (PG: in trace buffer) when it fails. This is
  3843 useful for figuring out why single step proofs like rule, erule or
  3844 assumption failed.
  3845 
  3846 * Pure: Locale specifications now produce predicate definitions
  3847 according to the body of text (covering assumptions modulo local
  3848 definitions); predicate "loc_axioms" covers newly introduced text,
  3849 while "loc" is cumulative wrt. all included locale expressions; the
  3850 latter view is presented only on export into the global theory
  3851 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3852 on the old view without predicates;
  3853 
  3854 * Pure: predefined locales "var" and "struct" are useful for sharing
  3855 parameters (as in CASL, for example); just specify something like
  3856 ``var x + var y + struct M'' as import;
  3857 
  3858 * Pure: improved thms_containing: proper indexing of facts instead of
  3859 raw theorems; check validity of results wrt. current name space;
  3860 include local facts of proof configuration (also covers active
  3861 locales), cover fixed variables in index; may use "_" in term
  3862 specification; an optional limit for the number of printed facts may
  3863 be given (the default is 40);
  3864 
  3865 * Pure: disallow duplicate fact bindings within new-style theory files
  3866 (batch-mode only);
  3867 
  3868 * Provers: improved induct method: assumptions introduced by case
  3869 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3870 the goal statement); "foo" still refers to all facts collectively;
  3871 
  3872 * Provers: the function blast.overloaded has been removed: all constants
  3873 are regarded as potentially overloaded, which improves robustness in exchange
  3874 for slight decrease in efficiency;
  3875 
  3876 * Provers/linorder: New generic prover for transitivity reasoning over
  3877 linear orders.  Note: this prover is not efficient!
  3878 
  3879 * Isar: preview of problems to finish 'show' now produce an error
  3880 rather than just a warning (in interactive mode);
  3881 
  3882 
  3883 *** HOL ***
  3884 
  3885 * arith(_tac)
  3886 
  3887  - Produces a counter example if it cannot prove a goal.
  3888    Note that the counter example may be spurious if the goal is not a formula
  3889    of quantifier-free linear arithmetic.
  3890    In ProofGeneral the counter example appears in the trace buffer.
  3891 
  3892  - Knows about div k and mod k where k is a numeral of type nat or int.
  3893 
  3894  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3895    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3896    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3897 
  3898 * simp's arithmetic capabilities have been enhanced a bit: it now
  3899 takes ~= in premises into account (by performing a case split);
  3900 
  3901 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3902 are distributed over a sum of terms;
  3903 
  3904 * New tactic "trans_tac" and method "trans" instantiate
  3905 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3906 "<=", "<" and "=").
  3907 
  3908 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3909 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3910 
  3911 * 'typedef' command has new option "open" to suppress the set
  3912 definition;
  3913 
  3914 * functions Min and Max on finite sets have been introduced (theory
  3915 Finite_Set);
  3916 
  3917 * attribute [symmetric] now works for relations as well; it turns
  3918 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3919 
  3920 * induct over a !!-quantified statement (say !!x1..xn):
  3921   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3922 
  3923 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3924 %x. None. Warning: empty_def now refers to the previously hidden definition
  3925 of the empty set.
  3926 
  3927 * Algebra: formalization of classical algebra.  Intended as base for
  3928 any algebraic development in Isabelle.  Currently covers group theory
  3929 (up to Sylow's theorem) and ring theory (Universal Property of
  3930 Univariate Polynomials).  Contributions welcome;
  3931 
  3932 * GroupTheory: deleted, since its material has been moved to Algebra;
  3933 
  3934 * Complex: new directory of the complex numbers with numeric constants,
  3935 nonstandard complex numbers, and some complex analysis, standard and
  3936 nonstandard (Jacques Fleuriot);
  3937 
  3938 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3939 
  3940 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3941 Fleuriot);
  3942 
  3943 * Real/HahnBanach: updated and adapted to locales;
  3944 
  3945 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3946 Gray and Kramer);
  3947 
  3948 * UNITY: added the Meier-Sanders theory of progress sets;
  3949 
  3950 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3951 as abstract algorithms, instantiated to the JVM;
  3952 
  3953 * Bali: Java source language formalization. Type system, operational
  3954 semantics, axiomatic semantics. Supported language features:
  3955 classes, interfaces, objects,virtual methods, static methods,
  3956 static/instance fields, arrays, access modifiers, definite
  3957 assignment, exceptions.
  3958 
  3959 
  3960 *** ZF ***
  3961 
  3962 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3963 universe, etc.);
  3964 
  3965 * Main ZF: virtually all theories converted to new-style format;
  3966 
  3967 
  3968 *** ML ***
  3969 
  3970 * Pure: Tactic.prove provides sane interface for internal proofs;
  3971 omits the infamous "standard" operation, so this is more appropriate
  3972 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3973 
  3974 * Pure: improved error reporting of simprocs;
  3975 
  3976 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3977 up simprocs;
  3978 
  3979 
  3980 *** Document preparation ***
  3981 
  3982 * uses \par instead of \\ for line breaks in theory text. This may
  3983 shift some page breaks in large documents. To get the old behaviour
  3984 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3985 
  3986 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3987 other packages
  3988 
  3989 * \<euro> now needs package babel/greek instead of marvosym (which
  3990 broke \Rightarrow)
  3991 
  3992 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3993 textcomp package)
  3994 
  3995 
  3996 
  3997 New in Isabelle2002 (March 2002)
  3998 --------------------------------
  3999 
  4000 *** Document preparation ***
  4001 
  4002 * greatly simplified document preparation setup, including more
  4003 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4004 instructive isatool mkdir; users should basically be able to get
  4005 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4006 users may run a separate document processing stage manually like this:
  4007 "isatool usedir -D output HOL Test && isatool document Test/output";
  4008 
  4009 * theory dependency graph may now be incorporated into documents;
  4010 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4011 with \includegraphics of LaTeX;
  4012 
  4013 * proper spacing of consecutive markup elements, especially text
  4014 blocks after section headings;
  4015 
  4016 * support bold style (for single symbols only), input syntax is like
  4017 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4018 
  4019 * \<bullet> is now output as bold \cdot by default, which looks much
  4020 better in printed text;
  4021 
  4022 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4023 note that these symbols are currently unavailable in Proof General /
  4024 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4025 
  4026 * isatool latex no longer depends on changed TEXINPUTS, instead
  4027 isatool document copies the Isabelle style files to the target
  4028 location;
  4029 
  4030 
  4031 *** Isar ***
  4032 
  4033 * Pure/Provers: improved proof by cases and induction;
  4034   - 'case' command admits impromptu naming of parameters (such as
  4035     "case (Suc n)");
  4036   - 'induct' method divinates rule instantiation from the inductive
  4037     claim; no longer requires excessive ?P bindings for proper
  4038     instantiation of cases;
  4039   - 'induct' method properly enumerates all possibilities of set/type
  4040     rules; as a consequence facts may be also passed through *type*
  4041     rules without further ado;
  4042   - 'induct' method now derives symbolic cases from the *rulified*
  4043     rule (before it used to rulify cases stemming from the internal
  4044     atomized version); this means that the context of a non-atomic
  4045     statement becomes is included in the hypothesis, avoiding the
  4046     slightly cumbersome show "PROP ?case" form;
  4047   - 'induct' may now use elim-style induction rules without chaining
  4048     facts, using ``missing'' premises from the goal state; this allows
  4049     rules stemming from inductive sets to be applied in unstructured
  4050     scripts, while still benefitting from proper handling of non-atomic
  4051     statements; NB: major inductive premises need to be put first, all
  4052     the rest of the goal is passed through the induction;
  4053   - 'induct' proper support for mutual induction involving non-atomic
  4054     rule statements (uses the new concept of simultaneous goals, see
  4055     below);
  4056   - append all possible rule selections, but only use the first
  4057     success (no backtracking);
  4058   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4059   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4060   - added 'print_induct_rules' (covered by help item in recent Proof
  4061     General versions);
  4062   - moved induct/cases attributes to Pure, methods to Provers;
  4063   - generic method setup instantiated for FOL and HOL;
  4064 
  4065 * Pure: support multiple simultaneous goal statements, for example
  4066 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4067 meta-level mechanism, this acts as if several individual goals had
  4068 been stated separately; in particular common proof methods need to be
  4069 repeated in order to cover all claims; note that a single elimination
  4070 step is *not* sufficient to establish the two conjunctions, so this
  4071 fails:
  4072 
  4073   assume "A & B" then have A and B ..   (*".." fails*)
  4074 
  4075 better use "obtain" in situations as above; alternative refer to
  4076 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4077 
  4078 * Pure: proper integration with ``locales''; unlike the original
  4079 version by Florian Kammller, Isar locales package high-level proof
  4080 contexts rather than raw logical ones (e.g. we admit to include
  4081 attributes everywhere); operations on locales include merge and
  4082 rename; support for implicit arguments (``structures''); simultaneous
  4083 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4084 some examples;
  4085 
  4086 * Pure: the following commands have been ``localized'', supporting a
  4087 target locale specification "(in name)": 'lemma', 'theorem',
  4088 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4089 stored both within the locale and at the theory level (exported and
  4090 qualified by the locale name);
  4091 
  4092 * Pure: theory goals may now be specified in ``long'' form, with
  4093 ad-hoc contexts consisting of arbitrary locale elements. for example
  4094 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4095 definitions may be given, too); the result is a meta-level rule with
  4096 the context elements being discharged in the obvious way;
  4097 
  4098 * Pure: new proof command 'using' allows to augment currently used
  4099 facts after a goal statement ('using' is syntactically analogous to
  4100 'apply', but acts on the goal's facts only); this allows chained facts
  4101 to be separated into parts given before and after a claim, as in
  4102 ``from a and b have C using d and e <proof>'';
  4103 
  4104 * Pure: renamed "antecedent" case to "rule_context";
  4105 
  4106 * Pure: new 'judgment' command records explicit information about the
  4107 object-logic embedding (used by several tools internally); no longer
  4108 use hard-wired "Trueprop";
  4109 
  4110 * Pure: added 'corollary' command;
  4111 
  4112 * Pure: fixed 'token_translation' command;
  4113 
  4114 * Pure: removed obsolete 'exported' attribute;
  4115 
  4116 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4117 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4118 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4119 
  4120 * Pure: method 'atomize' presents local goal premises as object-level
  4121 statements (atomic meta-level propositions); setup controlled via
  4122 rewrite rules declarations of 'atomize' attribute; example
  4123 application: 'induct' method with proper rule statements in improper
  4124 proof *scripts*;
  4125 
  4126 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4127 now consider the syntactic context of assumptions, giving a better
  4128 chance to get type-inference of the arguments right (this is
  4129 especially important for locales);
  4130 
  4131 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4132 mode;
  4133 
  4134 * Pure/obtain: the formal conclusion "thesis", being marked as
  4135 ``internal'', may no longer be reference directly in the text;
  4136 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4137 situations;
  4138 
  4139 * Pure: generic 'sym' attribute which declares a rule both as pure
  4140 'elim?' and for the 'symmetric' operation;
  4141 
  4142 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4143 text; the fixed correlation with particular command syntax has been
  4144 discontinued;
  4145 
  4146 * Pure: new method 'rules' is particularly well-suited for proof
  4147 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4148 but often produces more compact proof terms with less detours;
  4149 
  4150 * Pure/Provers/classical: simplified integration with pure rule
  4151 attributes and methods; the classical "intro?/elim?/dest?"
  4152 declarations coincide with the pure ones; the "rule" method no longer
  4153 includes classically swapped intros; "intro" and "elim" methods no
  4154 longer pick rules from the context; also got rid of ML declarations
  4155 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4156 INCOMPATIBILITY;
  4157 
  4158 * Provers/classical: attribute 'swapped' produces classical inversions
  4159 of introduction rules;
  4160 
  4161 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4162 rules instead of full simplifier context; 'iff' attribute handles
  4163 conditional rules;
  4164 
  4165 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4166 
  4167 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4168 "(permissive)" option to recover old behavior;
  4169 
  4170 * HOL: 'inductive' no longer features separate (collective) attributes
  4171 for 'intros' (was found too confusing);
  4172 
  4173 * HOL: properly declared induction rules less_induct and
  4174 wf_induct_rule;
  4175 
  4176 
  4177 *** HOL ***
  4178 
  4179 * HOL: moved over to sane numeral syntax; the new policy is as
  4180 follows:
  4181 
  4182   - 0 and 1 are polymorphic constants, which are defined on any
  4183   numeric type (nat, int, real etc.);
  4184 
  4185   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4186   binary representation internally;
  4187 
  4188   - type nat has special constructor Suc, and generally prefers Suc 0
  4189   over 1::nat and Suc (Suc 0) over 2::nat;
  4190 
  4191 This change may cause significant problems of INCOMPATIBILITY; here
  4192 are some hints on converting existing sources:
  4193 
  4194   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4195   entities, so expressions involving "-" (unary or binary minus) need
  4196   to be spaced properly;
  4197 
  4198   - existing occurrences of "1" may need to be constraint "1::nat" or
  4199   even replaced by Suc 0; similar for old "2";
  4200 
  4201   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4202 
  4203   - remove all special provisions on numerals in proofs;
  4204 
  4205 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4206 representation (depends on bin_arith_simps in the default context);
  4207 
  4208 * HOL: symbolic syntax for x^2 (numeral 2);
  4209 
  4210 * HOL: the class of all HOL types is now called "type" rather than
  4211 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4212 in axclass/classes, instance/arities, and (usually rare) occurrences
  4213 in typings (of consts etc.); internally the class is called
  4214 "HOL.type", ML programs should refer to HOLogic.typeS;
  4215 
  4216 * HOL/record package improvements:
  4217   - new derived operations "fields" to build a partial record section,
  4218     "extend" to promote a fixed record to a record scheme, and
  4219     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4220     declared as simp by default;
  4221   - shared operations ("more", "fields", etc.) now need to be always
  4222     qualified) --- potential INCOMPATIBILITY;
  4223   - removed "make_scheme" operations (use "make" with "extend") --
  4224     INCOMPATIBILITY;
  4225   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4226   - provides cases/induct rules for use with corresponding Isar
  4227     methods (for concrete records, record schemes, concrete more
  4228     parts, and schematic more parts -- in that order);
  4229   - internal definitions directly based on a light-weight abstract
  4230     theory of product types over typedef rather than datatype;
  4231 
  4232 * HOL: generic code generator for generating executable ML code from
  4233 specifications; specific support for HOL constructs such as inductive
  4234 datatypes and sets, as well as recursive functions; can be invoked
  4235 via 'generate_code' theory section;
  4236 
  4237 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4238 
  4239 * HOL: consolidated and renamed several theories.  In particular:
  4240         Ord.thy has been absorbed into HOL.thy
  4241         String.thy has been absorbed into List.thy
  4242 
  4243 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4244 (beware of argument permutation!);
  4245 
  4246 * HOL: linorder_less_split superseded by linorder_cases;
  4247 
  4248 * HOL/List: "nodups" renamed to "distinct";
  4249 
  4250 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4251 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4252   - Ex_def has changed, now need to use some_eq_ex
  4253 
  4254 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4255 in this (rare) case use:
  4256 
  4257   delSWrapper "split_all_tac"
  4258   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4259 
  4260 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4261 MAY FAIL;
  4262 
  4263 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4264 Isabelle's type classes, ^ on functions and relations has too general
  4265 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4266 necessary to attach explicit type constraints;
  4267 
  4268 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4269 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4270 renamed accordingly (eg "compI" -> "rel_compI").
  4271 
  4272 * HOL: syntax translations now work properly with numerals and records
  4273 expressions;
  4274 
  4275 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4276 of "lam" -- INCOMPATIBILITY;
  4277 
  4278 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4279 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4280 renamed "Product_Type.unit";
  4281 
  4282 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4283 
  4284 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4285 the "cases" method);
  4286 
  4287 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4288 Florian Kammller);
  4289 
  4290 * HOL/IMP: updated and converted to new-style theory format; several
  4291 parts turned into readable document, with proper Isar proof texts and
  4292 some explanations (by Gerwin Klein);
  4293 
  4294 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4295 
  4296 * HOL-Hyperreal is now a logic image;
  4297 
  4298 
  4299 *** HOLCF ***
  4300 
  4301 * Isar: consts/constdefs supports mixfix syntax for continuous
  4302 operations;
  4303 
  4304 * Isar: domain package adapted to new-style theory format, e.g. see
  4305 HOLCF/ex/Dnat.thy;
  4306 
  4307 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4308 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4309 lift.induct_tac, always use UU instead of Undef;
  4310 
  4311 * HOLCF/IMP: updated and converted to new-style theory;
  4312 
  4313 
  4314 *** ZF ***
  4315 
  4316 * Isar: proper integration of logic-specific tools and packages,
  4317 including theory commands '(co)inductive', '(co)datatype',
  4318 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4319 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4320 
  4321 * theory Main no longer includes AC; for the Axiom of Choice, base
  4322 your theory on Main_ZFC;
  4323 
  4324 * the integer library now covers quotients and remainders, with many
  4325 laws relating division to addition, multiplication, etc.;
  4326 
  4327 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4328 typeless version of the formalism;
  4329 
  4330 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4331 format;
  4332 
  4333 * ZF/Induct: new directory for examples of inductive definitions,
  4334 including theory Multiset for multiset orderings; converted to
  4335 new-style theory format;
  4336 
  4337 * ZF: many new theorems about lists, ordinals, etc.;
  4338 
  4339 
  4340 *** General ***
  4341 
  4342 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4343 variable proof controls level of detail: 0 = no proofs (only oracle
  4344 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4345 also ref manual for further ML interfaces;
  4346 
  4347 * Pure/axclass: removed obsolete ML interface
  4348 goal_subclass/goal_arity;
  4349 
  4350 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4351 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4352 separate tokens, so expressions involving minus need to be spaced
  4353 properly;
  4354 
  4355 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4356 rather than "infixl" or "infixr";
  4357 
  4358 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4359 sort constraint specifications in type inference; e.g. "x::_::foo"
  4360 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4361 type variable);
  4362 
  4363 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4364 control output of nested => (types); the default behavior is
  4365 "type_brackets";
  4366 
  4367 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4368 tokens into AST constants;
  4369 
  4370 * Pure/syntax: prefer later declarations of translations and print
  4371 translation functions; potential INCOMPATIBILITY: need to reverse
  4372 multiple declarations for same syntax element constant;
  4373 
  4374 * Pure/show_hyps reset by default (in accordance to existing Isar
  4375 practice);
  4376 
  4377 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4378 addSafter;
  4379 
  4380 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4381 as well;
  4382 
  4383 * system: tested support for MacOS X; should be able to get Isabelle +
  4384 Proof General to work in a plain Terminal after installing Poly/ML
  4385 (e.g. from the Isabelle distribution area) and GNU bash alone
  4386 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4387 support requires further installations, e.g. from
  4388 http://fink.sourceforge.net/);
  4389 
  4390 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4391 
  4392 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4393 of 40 MB), cf. ML_OPTIONS;
  4394 
  4395 * system: Proof General keywords specification is now part of the
  4396 Isabelle distribution (see etc/isar-keywords.el);
  4397 
  4398 * system: support for persistent Proof General sessions (refrain from
  4399 outdating all loaded theories on startup); user may create writable
  4400 logic images like this: ``isabelle -q HOL Test'';
  4401 
  4402 * system: smart selection of Isabelle process versus Isabelle
  4403 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4404 run both "isabelle" and "Isabelle" even if file names are badly
  4405 damaged (executable inspects the case of the first letter of its own
  4406 name); added separate "isabelle-process" and "isabelle-interface";
  4407 
  4408 * system: refrain from any attempt at filtering input streams; no
  4409 longer support ``8bit'' encoding of old isabelle font, instead proper
  4410 iso-latin characters may now be used; the related isatools
  4411 "symbolinput" and "nonascii" have disappeared as well;
  4412 
  4413 * system: removed old "xterm" interface (the print modes "xterm" and
  4414 "xterm_color" are still available for direct use in a suitable
  4415 terminal);
  4416 
  4417 
  4418 
  4419 New in Isabelle99-2 (February 2001)
  4420 -----------------------------------
  4421 
  4422 *** Overview of INCOMPATIBILITIES ***
  4423 
  4424 * HOL: please note that theories in the Library and elsewhere often use the
  4425 new-style (Isar) format; to refer to their theorems in an ML script you must
  4426 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4427 
  4428 * HOL: inductive package no longer splits induction rule aggressively,
  4429 but only as far as specified by the introductions given; the old
  4430 format may be recovered via ML function complete_split_rule or attribute
  4431 'split_rule (complete)';
  4432 
  4433 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4434 gfp_Tarski to gfp_unfold;
  4435 
  4436 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4437 
  4438 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4439 relation); infix "^^" has been renamed "``"; infix "``" has been
  4440 renamed "`"; "univalent" has been renamed "single_valued";
  4441 
  4442 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4443 operation;
  4444 
  4445 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4446 
  4447 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4448 
  4449 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4450 consequence, it is no longer monotonic wrt. the local goal context
  4451 (which is now passed through the inductive cases);
  4452 
  4453 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4454 \<gg> to \<ggreater>;
  4455 
  4456 
  4457 *** Document preparation ***
  4458 
  4459 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4460 available: are "it" for near math-mode best-style output, "sl" for
  4461 slanted text style, and "tt" for plain type-writer; if no
  4462 \isabellestyle command is given, output is according to slanted
  4463 type-writer);
  4464 
  4465 * support sub/super scripts (for single symbols only), input syntax is
  4466 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4467 
  4468 * some more standard symbols; see Appendix A of the system manual for
  4469 the complete list of symbols defined in isabellesym.sty;
  4470 
  4471 * improved isabelle style files; more abstract symbol implementation
  4472 (should now use \isamath{...} and \isatext{...} in custom symbol
  4473 definitions);
  4474 
  4475 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4476 state; Note that presentation of goal states does not conform to
  4477 actual human-readable proof documents.  Please do not include goal
  4478 states into document output unless you really know what you are doing!
  4479 
  4480 * proper indentation of antiquoted output with proportional LaTeX
  4481 fonts;
  4482 
  4483 * no_document ML operator temporarily disables LaTeX document
  4484 generation;
  4485 
  4486 * isatool unsymbolize tunes sources for plain ASCII communication;
  4487 
  4488 
  4489 *** Isar ***
  4490 
  4491 * Pure: Isar now suffers initial goal statements to contain unbound
  4492 schematic variables (this does not conform to actual readable proof
  4493 documents, due to unpredictable outcome and non-compositional proof
  4494 checking); users who know what they are doing may use schematic goals
  4495 for Prolog-style synthesis of proven results;
  4496 
  4497 * Pure: assumption method (an implicit finishing) now handles actual
  4498 rules as well;
  4499 
  4500 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4501 initial goal, declare "that" only as Pure intro (only for single
  4502 steps); the "that" rule assumption may now be involved in implicit
  4503 finishing, thus ".." becomes a feasible for trivial obtains;
  4504 
  4505 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4506 instance proofs may be performed by "..";
  4507 
  4508 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4509 statements as well;
  4510 
  4511 * Pure: more robust selection of calculational rules;
  4512 
  4513 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4514 rule (as well as the assumption rule);
  4515 
  4516 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4517 lemmas, using the graph browser tool;
  4518 
  4519 * Pure: predict failure of "show" in interactive mode;
  4520 
  4521 * Pure: 'thms_containing' now takes actual terms as arguments;
  4522 
  4523 * HOL: improved method 'induct' --- now handles non-atomic goals
  4524 (potential INCOMPATIBILITY); tuned error handling;
  4525 
  4526 * HOL: cases and induct rules now provide explicit hints about the
  4527 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4528 any remaining facts are inserted into the goal verbatim;
  4529 
  4530 * HOL: local contexts (aka cases) may now contain term bindings as
  4531 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4532 the result to be shown in each case;
  4533 
  4534 * HOL: added 'recdef_tc' command;
  4535 
  4536 * isatool convert assists in eliminating legacy ML scripts;
  4537 
  4538 
  4539 *** HOL ***
  4540 
  4541 * HOL/Library: a collection of generic theories to be used together
  4542 with main HOL; the theory loader path already includes this directory
  4543 by default; the following existing theories have been moved here:
  4544 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4545 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4546 
  4547 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4548 modelling and verification task performed in Isabelle/HOL +
  4549 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4550 
  4551 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4552 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4553 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4554 'domain', this makes the theory consistent with mathematical
  4555 literature;
  4556 
  4557 * HOL basics: added overloaded operations "inverse" and "divide"
  4558 (infix "/"), syntax for generic "abs" operation, generic summation
  4559 operator \<Sum>;
  4560 
  4561 * HOL/typedef: simplified package, provide more useful rules (see also
  4562 HOL/subset.thy);
  4563 
  4564 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4565 now expressed as a proper nested rule (old-style tactic scripts may
  4566 require atomize_strip_tac to cope with non-atomic premises);
  4567 
  4568 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4569 to "split_conv" (old name still available for compatibility);
  4570 
  4571 * HOL: improved concrete syntax for strings (e.g. allows translation
  4572 rules with string literals);
  4573 
  4574 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4575  and Fleuriot's mechanization of analysis, including the transcendental
  4576  functions for the reals;
  4577 
  4578 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4579 
  4580 
  4581 *** CTT ***
  4582 
  4583 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4584 "lam" is displayed as TWO lambda-symbols
  4585 
  4586 * CTT: theory Main now available, containing everything (that is, Bool
  4587 and Arith);
  4588 
  4589 
  4590 *** General ***
  4591 
  4592 * Pure: the Simplifier has been implemented properly as a derived rule
  4593 outside of the actual kernel (at last!); the overall performance
  4594 penalty in practical applications is about 50%, while reliability of
  4595 the Isabelle inference kernel has been greatly improved;
  4596 
  4597 * print modes "brackets" and "no_brackets" control output of nested =>
  4598 (types) and ==> (props); the default behaviour is "brackets";
  4599 
  4600 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4601 as assumptions as well;
  4602 
  4603 * system: support Poly/ML 4.0;
  4604 
  4605 * system: isatool install handles KDE version 1 or 2;
  4606 
  4607 
  4608 
  4609 New in Isabelle99-1 (October 2000)
  4610 ----------------------------------
  4611 
  4612 *** Overview of INCOMPATIBILITIES ***
  4613 
  4614 * HOL: simplification of natural numbers is much changed; to partly
  4615 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4616 issue the following ML commands:
  4617 
  4618   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4619   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4620 
  4621 * HOL: simplification no longer dives into case-expressions; this is
  4622 controlled by "t.weak_case_cong" for each datatype t;
  4623 
  4624 * HOL: nat_less_induct renamed to less_induct;
  4625 
  4626 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4627 fixsome to patch .thy and .ML sources automatically;
  4628 
  4629   select_equality  -> some_equality
  4630   select_eq_Ex     -> some_eq_ex
  4631   selectI2EX       -> someI2_ex
  4632   selectI2         -> someI2
  4633   selectI          -> someI
  4634   select1_equality -> some1_equality
  4635   Eps_sym_eq       -> some_sym_eq_trivial
  4636   Eps_eq           -> some_eq_trivial
  4637 
  4638 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4639 
  4640 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4641 instead);
  4642 
  4643 * HOL: the recursion equations generated by 'recdef' are now called
  4644 f.simps instead of f.rules;
  4645 
  4646 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4647 
  4648 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4649 sometimes be needed;
  4650 
  4651 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4652 
  4653 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4654 
  4655 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4656 product is now "<*>" instead of "Times"; the lexicographic product is
  4657 now "<*lex*>" instead of "**";
  4658 
  4659 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4660 of main HOL, but was unused); better use HOL's datatype package;
  4661 
  4662 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4663 the old syntax may be recovered as follows:
  4664 
  4665   syntax (symbols)
  4666     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4667       (infixl "\\<oplus>" 100)
  4668 
  4669 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4670 
  4671 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4672 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4673 internally;
  4674 
  4675 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4676 changed from A/r to A//r;
  4677 
  4678 * ZF: new treatment of arithmetic (nat & int) may break some old
  4679 proofs;
  4680 
  4681 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4682 rulify -> rule_format, elimify -> elim_format, ...);
  4683 
  4684 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4685 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4686 should have to change intro!! to intro? only); replaced "delrule" by
  4687 "rule del";
  4688 
  4689 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4690 
  4691 * Provers: strengthened force_tac by using new first_best_tac;
  4692 
  4693 * LaTeX document preparation: several changes of isabelle.sty (see
  4694 lib/texinputs);
  4695 
  4696 
  4697 *** Document preparation ***
  4698 
  4699 * formal comments (text blocks etc.) in new-style theories may now
  4700 contain antiquotations of thm/prop/term/typ/text to be presented
  4701 according to latex print mode; concrete syntax is like this:
  4702 @{term[show_types] "f(x) = a + x"};
  4703 
  4704 * isatool mkdir provides easy setup of Isabelle session directories,
  4705 including proper document sources;
  4706 
  4707 * generated LaTeX sources are now deleted after successful run
  4708 (isatool document -c); may retain a copy somewhere else via -D option
  4709 of isatool usedir;
  4710 
  4711 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4712 style files, achieving self-contained LaTeX sources and simplifying
  4713 LaTeX debugging;
  4714 
  4715 * old-style theories now produce (crude) LaTeX output as well;
  4716 
  4717 * browser info session directories are now self-contained (may be put
  4718 on WWW server seperately); improved graphs of nested sessions; removed
  4719 graph for 'all sessions';
  4720 
  4721 * several improvements in isabelle style files; \isabellestyle{it}
  4722 produces fake math mode output; \isamarkupheader is now \section by
  4723 default; see lib/texinputs/isabelle.sty etc.;
  4724 
  4725 
  4726 *** Isar ***
  4727 
  4728 * Isar/Pure: local results and corresponding term bindings are now
  4729 subject to Hindley-Milner polymorphism (similar to ML); this
  4730 accommodates incremental type-inference very nicely;
  4731 
  4732 * Isar/Pure: new derived language element 'obtain' supports
  4733 generalized existence reasoning;
  4734 
  4735 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4736 support accumulation of results, without applying any rules yet;
  4737 useful to collect intermediate results without explicit name
  4738 references, and for use with transitivity rules with more than 2
  4739 premises;
  4740 
  4741 * Isar/Pure: scalable support for case-analysis type proofs: new
  4742 'case' language element refers to local contexts symbolically, as
  4743 produced by certain proof methods; internally, case names are attached
  4744 to theorems as "tags";
  4745 
  4746 * Isar/Pure: theory command 'hide' removes declarations from
  4747 class/type/const name spaces;
  4748 
  4749 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4750 indicate potential overloading;
  4751 
  4752 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4753 
  4754 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4755 "{a,b,c}" instead of {a,b,c};
  4756 
  4757 * Isar/Pure now provides its own version of intro/elim/dest
  4758 attributes; useful for building new logics, but beware of confusion
  4759 with the version in Provers/classical;
  4760 
  4761 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4762 case name 'antecedent';
  4763 
  4764 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4765 to the current context is now done automatically);
  4766 
  4767 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4768 for definining proof methods in ML;
  4769 
  4770 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4771 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4772 most cases, one should have to change intro!! to intro? only);
  4773 replaced "delrule" by "rule del";
  4774 
  4775 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4776 'symmetric' attribute (the latter supercedes [RS sym]);
  4777 
  4778 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4779 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4780 well (including splits);
  4781 
  4782 * Isar/Provers: Simplifier and Classical methods now support all kind
  4783 of modifiers used in the past, including 'cong', 'iff', etc.
  4784 
  4785 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4786 of Simplifier and Classical reasoner);
  4787 
  4788 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4789 now support named cases; major packages (inductive, datatype, primrec,
  4790 recdef) support case names and properly name parameters;
  4791 
  4792 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4793 monotonicity conditions are extracted to be proven at end of
  4794 calculations;
  4795 
  4796 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4797 method anyway;
  4798 
  4799 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4800 split_if split_if_asm; datatype package provides theorems foo.splits =
  4801 foo.split foo.split_asm for each datatype;
  4802 
  4803 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4804 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4805 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4806 use "(cases (simplified))" method in proper proof texts);
  4807 
  4808 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4809 
  4810 * Isar: names of theorems etc. may be natural numbers as well;
  4811 
  4812 * Isar: 'pr' command: optional arguments for goals_limit and
  4813 ProofContext.prems_limit; no longer prints theory contexts, but only
  4814 proof states;
  4815 
  4816 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4817 additional print modes to be specified; e.g. "pr(latex)" will print
  4818 proof state according to the Isabelle LaTeX style;
  4819 
  4820 * Isar: improved support for emulating tactic scripts, including proof
  4821 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4822 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4823 (for HOL datatypes);
  4824 
  4825 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4826 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4827 'proof method scripts' have to be in depth-first order;
  4828 
  4829 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4830 
  4831 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4832 should instead use individual commands for printing items
  4833 (print_commands, print_methods etc.);
  4834 
  4835 * Isar: added 'nothing' --- the empty list of theorems;
  4836 
  4837 
  4838 *** HOL ***
  4839 
  4840 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4841 corresponding virtual machine and a specification of its bytecode
  4842 verifier and a lightweight bytecode verifier, including proofs of
  4843 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4844 Cornelia Pusch (see also the homepage of project Bali at
  4845 http://isabelle.in.tum.de/Bali/);
  4846 
  4847 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4848 Clemens Ballarin;
  4849 
  4850 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4851 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4852 Rasmussen;
  4853 
  4854 * HOL/Lattice: fundamental concepts of lattice theory and order
  4855 structures, including duals, properties of bounds versus algebraic
  4856 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4857 Theorem for complete lattices etc.; may also serve as a demonstration
  4858 for abstract algebraic reasoning using axiomatic type classes, and
  4859 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4860 
  4861 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4862 von Oheimb;
  4863 
  4864 * HOL/IMPP: extension of IMP with local variables and mutually
  4865 recursive procedures, by David von Oheimb;
  4866 
  4867 * HOL/Lambda: converted into new-style theory and document;
  4868 
  4869 * HOL/ex/Multiquote: example of multiple nested quotations and
  4870 anti-quotations -- basically a generalized version of de-Bruijn
  4871 representation; very useful in avoiding lifting of operations;
  4872 
  4873 * HOL/record: added general record equality rule to simpset; fixed
  4874 select-update simplification procedure to handle extended records as
  4875 well; admit "r" as field name;
  4876 
  4877 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4878 other numeric types and also as the identity of groups, rings, etc.;
  4879 
  4880 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4881 Types nat and int belong to this axclass;
  4882 
  4883 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4884    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4885    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4886   two terms #m*u and #n*u are replaced by #(m+n)*u
  4887     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4888   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4889     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4890 
  4891 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4892 powerful prover for predicate logic but knows nothing of clasets; see
  4893 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4894 
  4895 * HOL: new version of "case_tac" subsumes both boolean case split and
  4896 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4897 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4898 
  4899 * HOL: simplification no longer dives into case-expressions: only the
  4900 selector expression is simplified, but not the remaining arms; to
  4901 enable full simplification of case-expressions for datatype t, you may
  4902 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4903 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4904 
  4905 * HOL/recdef: the recursion equations generated by 'recdef' for
  4906 function 'f' are now called f.simps instead of f.rules; if all
  4907 termination conditions are proved automatically, these simplification
  4908 rules are added to the simpset, as in primrec; rules may be named
  4909 individually as well, resulting in a separate list of theorems for
  4910 each equation;
  4911 
  4912 * HOL/While is a new theory that provides a while-combinator. It
  4913 permits the definition of tail-recursive functions without the
  4914 provision of a termination measure. The latter is necessary once the
  4915 invariant proof rule for while is applied.
  4916 
  4917 * HOL: new (overloaded) notation for the set of elements below/above
  4918 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4919 
  4920 * HOL: theorems impI, allI, ballI bound as "strip";
  4921 
  4922 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4923 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4924 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4925 
  4926 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4927 
  4928 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4929 main HOL, but was unused);
  4930 
  4931 * HOL: fewer consts declared as global (e.g. have to refer to
  4932 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4933 
  4934 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4935 in case of overlap with user translations (e.g. judgements over
  4936 tuples); (note that the underlying logical represenation is still
  4937 bogus);
  4938 
  4939 
  4940 *** ZF ***
  4941 
  4942 * ZF: simplification automatically cancels common terms in arithmetic
  4943 expressions over nat and int;
  4944 
  4945 * ZF: new treatment of nat to minimize type-checking: all operators
  4946 coerce their operands to a natural number using the function natify,
  4947 making the algebraic laws unconditional;
  4948 
  4949 * ZF: as above, for int: operators coerce their operands to an integer
  4950 using the function intify;
  4951 
  4952 * ZF: the integer library now contains many of the usual laws for the
  4953 orderings, including $<=, and monotonicity laws for $+ and $*;
  4954 
  4955 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4956 simplification;
  4957 
  4958 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4959 to the simplifier and classical reasoner simultaneously;
  4960 
  4961 
  4962 *** General ***
  4963 
  4964 * Provers: blast_tac now handles actual object-logic rules as
  4965 assumptions; note that auto_tac uses blast_tac internally as well;
  4966 
  4967 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4968 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4969 
  4970 * Provers: delrules now handles destruct rules as well (no longer need
  4971 explicit make_elim);
  4972 
  4973 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4974   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4975 use instead the strong form,
  4976   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4977 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4978 from destruct-rules;
  4979 
  4980 * Provers: Simplifier.easy_setup provides a fast path to basic
  4981 Simplifier setup for new object-logics;
  4982 
  4983 * Pure: AST translation rules no longer require constant head on LHS;
  4984 
  4985 * Pure: improved name spaces: ambiguous output is qualified; support
  4986 for hiding of names;
  4987 
  4988 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4989 XSYMBOL_HOME; no longer need to do manual configuration in most
  4990 situations;
  4991 
  4992 * system: compression of ML heaps images may now be controlled via -c
  4993 option of isabelle and isatool usedir (currently only observed by
  4994 Poly/ML);
  4995 
  4996 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4997 useful for remote X11);
  4998 
  4999 * system: provide TAGS file for Isabelle sources;
  5000 
  5001 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5002 order;
  5003 
  5004 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5005 timing flag supersedes proof_timing and Toplevel.trace;
  5006 
  5007 * ML: new combinators |>> and |>>> for incremental transformations
  5008 with secondary results (e.g. certain theory extensions):
  5009 
  5010 * ML: PureThy.add_defs gets additional argument to indicate potential
  5011 overloading (usually false);
  5012 
  5013 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5014 results;
  5015 
  5016 
  5017 
  5018 New in Isabelle99 (October 1999)
  5019 --------------------------------
  5020 
  5021 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5022 
  5023 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5024 are no longer simplified.  (This allows the simplifier to unfold recursive
  5025 functional programs.)  To restore the old behaviour, declare
  5026 
  5027     Delcongs [if_weak_cong];
  5028 
  5029 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5030 complement;
  5031 
  5032 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5033 
  5034 * HOL/datatype: mutual_induct_tac no longer exists --
  5035   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5036 
  5037 * HOL/typedef: fixed type inference for representing set; type
  5038 arguments now have to occur explicitly on the rhs as type constraints;
  5039 
  5040 * ZF: The con_defs part of an inductive definition may no longer refer
  5041 to constants declared in the same theory;
  5042 
  5043 * HOL, ZF: the function mk_cases, generated by the inductive
  5044 definition package, has lost an argument.  To simplify its result, it
  5045 uses the default simpset instead of a supplied list of theorems.
  5046 
  5047 * HOL/List: the constructors of type list are now Nil and Cons;
  5048 
  5049 * Simplifier: the type of the infix ML functions
  5050         setSSolver addSSolver setSolver addSolver
  5051 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5052 for packaging solvers. A solver is created via
  5053         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5054 where the string argument is only a comment.
  5055 
  5056 
  5057 *** Proof tools ***
  5058 
  5059 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5060 decision procedure for linear arithmetic. Currently it is used for
  5061 types `nat', `int', and `real' in HOL (see below); it can, should and
  5062 will be instantiated for other types and logics as well.
  5063 
  5064 * The simplifier now accepts rewrite rules with flexible heads, eg
  5065      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5066   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5067   matching.
  5068 
  5069 
  5070 *** General ***
  5071 
  5072 * New Isabelle/Isar subsystem provides an alternative to traditional
  5073 tactical theorem proving; together with the ProofGeneral/isar user
  5074 interface it offers an interactive environment for developing human
  5075 readable proof documents (Isar == Intelligible semi-automated
  5076 reasoning); for further information see isatool doc isar-ref,
  5077 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5078 
  5079 * improved and simplified presentation of theories: better HTML markup
  5080 (including colors), graph views in several sizes; isatool usedir now
  5081 provides a proper interface for user theories (via -P option); actual
  5082 document preparation based on (PDF)LaTeX is available as well (for
  5083 new-style theories only); see isatool doc system for more information;
  5084 
  5085 * native support for Proof General, both for classic Isabelle and
  5086 Isabelle/Isar;
  5087 
  5088 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5089 using the graph browser tool;
  5090 
  5091 * Isabelle manuals now also available as PDF;
  5092 
  5093 * theory loader rewritten from scratch (may not be fully
  5094 bug-compatible); old loadpath variable has been replaced by show_path,
  5095 add_path, del_path, reset_path functions; new operations such as
  5096 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5097 isatool doc ref);
  5098 
  5099 * improved isatool install: option -k creates KDE application icon,
  5100 option -p DIR installs standalone binaries;
  5101 
  5102 * added ML_PLATFORM setting (useful for cross-platform installations);
  5103 more robust handling of platform specific ML images for SML/NJ;
  5104 
  5105 * the settings environment is now statically scoped, i.e. it is never
  5106 created again in sub-processes invoked from isabelle, isatool, or
  5107 Isabelle;
  5108 
  5109 * path element specification '~~' refers to '$ISABELLE_HOME';
  5110 
  5111 * in locales, the "assumes" and "defines" parts may be omitted if
  5112 empty;
  5113 
  5114 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5115 long arrows);
  5116 
  5117 * new print_mode "HTML";
  5118 
  5119 * new flag show_tags controls display of tags of theorems (which are
  5120 basically just comments that may be attached by some tools);
  5121 
  5122 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5123 mode and goal output format:
  5124 
  5125 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5126 244c244
  5127 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5128 ---
  5129 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5130 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5131 181c181
  5132 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5133 ---
  5134 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5135 
  5136 * function bind_thms stores lists of theorems (cf. bind_thm);
  5137 
  5138 * new shorthand tactics ftac, eatac, datac, fatac;
  5139 
  5140 * qed (and friends) now accept "" as result name; in that case the
  5141 theorem is not stored, but proper checks and presentation of the
  5142 result still apply;
  5143 
  5144 * theorem database now also indexes constants "Trueprop", "all",
  5145 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5146 
  5147 
  5148 *** HOL ***
  5149 
  5150 ** HOL arithmetic **
  5151 
  5152 * There are now decision procedures for linear arithmetic over nat and
  5153 int:
  5154 
  5155 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5156 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5157 are treated as atomic; subformulae not involving type `nat' or `int'
  5158 are ignored; quantified subformulae are ignored unless they are
  5159 positive universal or negative existential. The tactic has to be
  5160 invoked by hand and can be a little bit slow. In particular, the
  5161 running time is exponential in the number of occurrences of `min' and
  5162 `max', and `-' on `nat'.
  5163 
  5164 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5165 (negated) (in)equalities among the premises and the conclusion into
  5166 account (i.e. no compound formulae) and does not know about `min' and
  5167 `max', and `-' on `nat'. It is fast and is used automatically by the
  5168 simplifier.
  5169 
  5170 NB: At the moment, these decision procedures do not cope with mixed
  5171 nat/int formulae where the two parts interact, such as `m < n ==>
  5172 int(m) < int(n)'.
  5173 
  5174 * HOL/Numeral provides a generic theory of numerals (encoded
  5175 efficiently as bit strings); setup for types nat/int/real is in place;
  5176 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5177 int, existing theories and proof scripts may require a few additional
  5178 type constraints;
  5179 
  5180 * integer division and remainder can now be performed on constant
  5181 arguments;
  5182 
  5183 * many properties of integer multiplication, division and remainder
  5184 are now available;
  5185 
  5186 * An interface to the Stanford Validity Checker (SVC) is available through the
  5187 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5188 are proved automatically.  SVC must be installed separately, and its results
  5189 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5190 invocation of the underlying oracle).  For SVC see
  5191   http://verify.stanford.edu/SVC
  5192 
  5193 * IsaMakefile: the HOL-Real target now builds an actual image;
  5194 
  5195 
  5196 ** HOL misc **
  5197 
  5198 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5199 (in Isabelle/Isar) -- by Gertrud Bauer;
  5200 
  5201 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5202 analysis for assembly languages with subtypes;
  5203 
  5204 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5205 -- avoids syntactic ambiguities and treats state, transition, and
  5206 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5207 changed syntax and (many) tactics;
  5208 
  5209 * HOL/inductive: Now also handles more general introduction rules such
  5210   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5211   theorems are now maintained within the theory (maintained via the
  5212   "mono" attribute);
  5213 
  5214 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5215   (using function types) such as
  5216 
  5217   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5218 
  5219 * HOL/record: record_simproc (part of the default simpset) takes care
  5220 of selectors applied to updated records; record_split_tac is no longer
  5221 part of the default claset; update_defs may now be removed from the
  5222 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5223 
  5224   claset_ref () := claset() addSWrapper record_split_wrapper;
  5225   Delsimprocs [record_simproc]
  5226 
  5227 * HOL/typedef: fixed type inference for representing set; type
  5228 arguments now have to occur explicitly on the rhs as type constraints;
  5229 
  5230 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5231 names rather than an ML expression;
  5232 
  5233 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5234 supplied later.  Program schemes can be defined, such as
  5235     "While B C s = (if B s then While B C (C s) else s)"
  5236 where the well-founded relation can be chosen after B and C have been given.
  5237 
  5238 * HOL/List: the constructors of type list are now Nil and Cons;
  5239 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5240 course, ML tools referring to List.list.op # etc. have to be adapted;
  5241 
  5242 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5243 disabled by default; run isabelle with option -m HOL to get back to
  5244 the original Gordon/HOL-style output;
  5245 
  5246 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5247 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5248 
  5249 * HOL basic syntax simplified (more orthogonal): all variants of
  5250 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5251 Eps operator is provided as well: "SOME x. P[x]";
  5252 
  5253 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5254 
  5255 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5256 thus available for user theories;
  5257 
  5258 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5259 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5260 time;
  5261 
  5262 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5263 several times and then mp;
  5264 
  5265 
  5266 *** LK ***
  5267 
  5268 * the notation <<...>> is now available as a notation for sequences of
  5269 formulas;
  5270 
  5271 * the simplifier is now installed
  5272 
  5273 * the axiom system has been generalized (thanks to Soren Heilmann)
  5274 
  5275 * the classical reasoner now has a default rule database
  5276 
  5277 
  5278 *** ZF ***
  5279 
  5280 * new primrec section allows primitive recursive functions to be given
  5281 directly (as in HOL) over datatypes and the natural numbers;
  5282 
  5283 * new tactics induct_tac and exhaust_tac for induction (or case
  5284 analysis) over datatypes and the natural numbers;
  5285 
  5286 * the datatype declaration of type T now defines the recursor T_rec;
  5287 
  5288 * simplification automatically does freeness reasoning for datatype
  5289 constructors;
  5290 
  5291 * automatic type-inference, with AddTCs command to insert new
  5292 type-checking rules;
  5293 
  5294 * datatype introduction rules are now added as Safe Introduction rules
  5295 to the claset;
  5296 
  5297 * the syntax "if P then x else y" is now available in addition to
  5298 if(P,x,y);
  5299 
  5300 
  5301 *** Internal programming interfaces ***
  5302 
  5303 * tuned simplifier trace output; new flag debug_simp;
  5304 
  5305 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5306 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5307 
  5308 * AxClass.axclass_tac lost the theory argument;
  5309 
  5310 * tuned current_goals_markers semantics: begin / end goal avoids
  5311 printing empty lines;
  5312 
  5313 * removed prs and prs_fn hook, which was broken because it did not
  5314 include \n in its semantics, forcing writeln to add one
  5315 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5316 string -> unit if you really want to output text without newline;
  5317 
  5318 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5319 plain output, interface builders may have to enable 'isabelle_font'
  5320 mode to get Isabelle font glyphs as before;
  5321 
  5322 * refined token_translation interface; INCOMPATIBILITY: output length
  5323 now of type real instead of int;
  5324 
  5325 * theory loader actions may be traced via new ThyInfo.add_hook
  5326 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5327 your own database of information attached to *whole* theories -- as
  5328 opposed to intra-theory data slots offered via TheoryDataFun;
  5329 
  5330 * proper handling of dangling sort hypotheses (at last!);
  5331 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5332 extra sort hypotheses that can be witnessed from the type signature;
  5333 the force_strip_shyps flag is gone, any remaining shyps are simply
  5334 left in the theorem (with a warning issued by strip_shyps_warning);
  5335 
  5336 
  5337 
  5338 New in Isabelle98-1 (October 1998)
  5339 ----------------------------------
  5340 
  5341 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5342 
  5343 * several changes of automated proof tools;
  5344 
  5345 * HOL: major changes to the inductive and datatype packages, including
  5346 some minor incompatibilities of theory syntax;
  5347 
  5348 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5349 called `inj_on';
  5350 
  5351 * HOL: removed duplicate thms in Arith:
  5352   less_imp_add_less  should be replaced by  trans_less_add1
  5353   le_imp_add_le      should be replaced by  trans_le_add1
  5354 
  5355 * HOL: unary minus is now overloaded (new type constraints may be
  5356 required);
  5357 
  5358 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5359 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5360 now taken as an integer constant.
  5361 
  5362 * Pure: ML function 'theory_of' renamed to 'theory';
  5363 
  5364 
  5365 *** Proof tools ***
  5366 
  5367 * Simplifier:
  5368   1. Asm_full_simp_tac is now more aggressive.
  5369      1. It will sometimes reorient premises if that increases their power to
  5370         simplify.
  5371      2. It does no longer proceed strictly from left to right but may also
  5372         rotate premises to achieve further simplification.
  5373      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5374      old Asm_full_simp_tac in that it does not rotate premises.
  5375   2. The simplifier now knows a little bit about nat-arithmetic.
  5376 
  5377 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5378 allows for selected deletion of wrappers, by introduction of names for
  5379 wrapper functionals.  This implies that addbefore, addSbefore,
  5380 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5381 and that adding two tactics with the same name overwrites the first
  5382 one (emitting a warning).
  5383   type wrapper = (int -> tactic) -> (int -> tactic)
  5384   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5385   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5386   delWrapper, delSWrapper: claset *  string            -> claset
  5387   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5388 
  5389 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5390 semantics; addbefore now affects only the unsafe part of step_tac
  5391 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5392 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5393 by Force_tac;
  5394 
  5395 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5396 compWrapper; added safe wrapper (and access functions for it);
  5397 
  5398 * HOL/split_all_tac is now much faster and fails if there is nothing
  5399 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5400 and the names of the automatically generated variables have changed.
  5401 split_all_tac has moved within claset() from unsafe wrappers to safe
  5402 wrappers, which means that !!-bound variables are split much more
  5403 aggressively, and safe_tac and clarify_tac now split such variables.
  5404 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5405 Note: the same holds for record_split_tac, which does the job of
  5406 split_all_tac for record fields.
  5407 
  5408 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5409 permanently to the default simpset using Addsplits just like
  5410 Addsimps. They can be removed via Delsplits just like
  5411 Delsimps. Lower-case versions are also available.
  5412 
  5413 * HOL/Simplifier: The rule split_if is now part of the default
  5414 simpset. This means that the simplifier will eliminate all occurrences
  5415 of if-then-else in the conclusion of a goal. To prevent this, you can
  5416 either remove split_if completely from the default simpset by
  5417 `Delsplits [split_if]' or remove it in a specific call of the
  5418 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5419 other case splitting rules to/from the default simpset: every datatype
  5420 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5421 t is the name of the datatype).
  5422 
  5423 * Classical reasoner / Simplifier combination: new force_tac (and
  5424 derivatives Force_tac, force) combines rewriting and classical
  5425 reasoning (and whatever other tools) similarly to auto_tac, but is
  5426 aimed to solve the given subgoal completely.
  5427 
  5428 
  5429 *** General ***
  5430 
  5431 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5432 and `goalw': the theory is no longer needed as an explicit argument -
  5433 the current theory context is used; assumptions are no longer returned
  5434 at the ML-level unless one of them starts with ==> or !!; it is
  5435 recommended to convert to these new commands using isatool fixgoal
  5436 (backup your sources first!);
  5437 
  5438 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5439 the current theory context, and 'theory' to lookup stored theories;
  5440 
  5441 * new theory section 'locale' for declaring constants, assumptions and
  5442 definitions that have local scope;
  5443 
  5444 * new theory section 'nonterminals' for purely syntactic types;
  5445 
  5446 * new theory section 'setup' for generic ML setup functions
  5447 (e.g. package initialization);
  5448 
  5449 * the distribution now includes Isabelle icons: see
  5450 lib/logo/isabelle-{small,tiny}.xpm;
  5451 
  5452 * isatool install - install binaries with absolute references to
  5453 ISABELLE_HOME/bin;
  5454 
  5455 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5456 
  5457 * print mode 'emacs' reserved for Isamode;
  5458 
  5459 * support multiple print (ast) translations per constant name;
  5460 
  5461 * theorems involving oracles are now printed with a suffixed [!];
  5462 
  5463 
  5464 *** HOL ***
  5465 
  5466 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5467 
  5468 * HOL/inductive package reorganized and improved: now supports mutual
  5469 definitions such as
  5470 
  5471   inductive EVEN ODD
  5472     intrs
  5473       null "0 : EVEN"
  5474       oddI "n : EVEN ==> Suc n : ODD"
  5475       evenI "n : ODD ==> Suc n : EVEN"
  5476 
  5477 new theorem list "elims" contains an elimination rule for each of the
  5478 recursive sets; inductive definitions now handle disjunctive premises
  5479 correctly (also ZF);
  5480 
  5481 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5482 "mutual_induct" no longer exists - the induction rule is always
  5483 contained in "induct";
  5484 
  5485 
  5486 * HOL/datatype package re-implemented and greatly improved: now
  5487 supports mutually recursive datatypes such as
  5488 
  5489   datatype
  5490     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5491             | SUM ('a aexp) ('a aexp)
  5492             | DIFF ('a aexp) ('a aexp)
  5493             | NUM 'a
  5494   and
  5495     'a bexp = LESS ('a aexp) ('a aexp)
  5496             | AND ('a bexp) ('a bexp)
  5497             | OR ('a bexp) ('a bexp)
  5498 
  5499 as well as indirectly recursive datatypes such as
  5500 
  5501   datatype
  5502     ('a, 'b) term = Var 'a
  5503                   | App 'b ((('a, 'b) term) list)
  5504 
  5505 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5506 induction on mutually / indirectly recursive datatypes.
  5507 
  5508 Primrec equations are now stored in theory and can be accessed via
  5509 <function_name>.simps.
  5510 
  5511 INCOMPATIBILITIES:
  5512 
  5513   - Theories using datatypes must now have theory Datatype as an
  5514     ancestor.
  5515   - The specific <typename>.induct_tac no longer exists - use the
  5516     generic induct_tac instead.
  5517   - natE has been renamed to nat.exhaust - use exhaust_tac
  5518     instead of res_inst_tac ... natE. Note that the variable
  5519     names in nat.exhaust differ from the names in natE, this
  5520     may cause some "fragile" proofs to fail.
  5521   - The theorems split_<typename>_case and split_<typename>_case_asm
  5522     have been renamed to <typename>.split and <typename>.split_asm.
  5523   - Since default sorts of type variables are now handled correctly,
  5524     some datatype definitions may have to be annotated with explicit
  5525     sort constraints.
  5526   - Primrec definitions no longer require function name and type
  5527     of recursive argument.
  5528 
  5529 Consider using isatool fixdatatype to adapt your theories and proof
  5530 scripts to the new package (backup your sources first!).
  5531 
  5532 
  5533 * HOL/record package: considerably improved implementation; now
  5534 includes concrete syntax for record types, terms, updates; theorems
  5535 for surjective pairing and splitting !!-bound record variables; proof
  5536 support is as follows:
  5537 
  5538   1) standard conversions (selectors or updates applied to record
  5539 constructor terms) are part of the standard simpset;
  5540 
  5541   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5542 made part of standard simpset and claset via addIffs;
  5543 
  5544   3) a tactic for record field splitting (record_split_tac) is part of
  5545 the standard claset (addSWrapper);
  5546 
  5547 To get a better idea about these rules you may retrieve them via
  5548 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5549 the name of your record type.
  5550 
  5551 The split tactic 3) conceptually simplifies by the following rule:
  5552 
  5553   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5554 
  5555 Thus any record variable that is bound by meta-all will automatically
  5556 blow up into some record constructor term, consequently the
  5557 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5558 solve record problems automatically.
  5559 
  5560 
  5561 * reorganized the main HOL image: HOL/Integ and String loaded by
  5562 default; theory Main includes everything;
  5563 
  5564 * automatic simplification of integer sums and comparisons, using cancellation;
  5565 
  5566 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5567 
  5568 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5569 
  5570 * many new identities for unions, intersections, set difference, etc.;
  5571 
  5572 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5573 called split_if, split_split, split_sum_case and split_nat_case (to go
  5574 with add/delsplits);
  5575 
  5576 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5577 (?x::unit) = (); this is made part of the default simpset, which COULD
  5578 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5579 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5580 unit_abs_eta_conv is added in order to counter the effect of
  5581 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5582 %u.f();
  5583 
  5584 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5585 makes more sense);
  5586 
  5587 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5588   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5589   disjointness reasoning but breaking a few old proofs.
  5590 
  5591 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5592 to 'converse' from 'inverse' (for compatibility with ZF and some
  5593 literature);
  5594 
  5595 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5596 the well-founded relation;
  5597 
  5598 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5599     Compl A.  The "Compl" syntax remains available as input syntax for this
  5600     release ONLY.
  5601 
  5602 * HOL/Update: new theory of function updates:
  5603     f(a:=b) == %x. if x=a then b else f x
  5604 may also be iterated as in f(a:=b,c:=d,...);
  5605 
  5606 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5607 
  5608 * HOL/List:
  5609   - new function list_update written xs[i:=v] that updates the i-th
  5610     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5611   - new function `upt' written [i..j(] which generates the list
  5612     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5613     bound write [i..j], which is a shorthand for [i..j+1(].
  5614   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5615 
  5616 * HOL/Arith:
  5617   - removed 'pred' (predecessor) function;
  5618   - generalized some theorems about n-1;
  5619   - many new laws about "div" and "mod";
  5620   - new laws about greatest common divisors (see theory ex/Primes);
  5621 
  5622 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5623 instead of "inverse";
  5624 
  5625 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5626   of the multiset ordering;
  5627 
  5628 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5629   (not included by default);
  5630 
  5631 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5632 
  5633 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5634   programs, i.e. different program variables may have different types.
  5635 
  5636 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5637   [previously, this check worked only if the rewrite rule was unconditional]
  5638   Now rew can involve either definitions or equalities (either == or =).
  5639 
  5640 
  5641 *** ZF ***
  5642 
  5643 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5644   only the theorems proved on ZF.ML;
  5645 
  5646 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5647   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5648   disjointness reasoning but breaking a few old proofs.
  5649 
  5650 * ZF/Update: new theory of function updates
  5651     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5652   may also be iterated as in f(a:=b,c:=d,...);
  5653 
  5654 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5655 
  5656 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5657   [previously, this check worked only if the rewrite rule was unconditional]
  5658   Now rew can involve either definitions or equalities (either == or =).
  5659 
  5660 * case_tac provided for compatibility with HOL
  5661     (like the old excluded_middle_tac, but with subgoals swapped)
  5662 
  5663 
  5664 *** Internal programming interfaces ***
  5665 
  5666 * Pure: several new basic modules made available for general use, see
  5667 also src/Pure/README;
  5668 
  5669 * improved the theory data mechanism to support encapsulation (data
  5670 kind name replaced by private Object.kind, acting as authorization
  5671 key); new type-safe user interface via functor TheoryDataFun; generic
  5672 print_data function becomes basically useless;
  5673 
  5674 * removed global_names compatibility flag -- all theory declarations
  5675 are qualified by default;
  5676 
  5677 * module Pure/Syntax now offers quote / antiquote translation
  5678 functions (useful for Hoare logic etc. with implicit dependencies);
  5679 see HOL/ex/Antiquote for an example use;
  5680 
  5681 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5682 cterm -> thm;
  5683 
  5684 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5685 subgoal;
  5686 
  5687 * Display.print_goals function moved to Locale.print_goals;
  5688 
  5689 * standard print function for goals supports current_goals_markers
  5690 variable for marking begin of proof, end of proof, start of goal; the
  5691 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5692 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5693 for example;
  5694 
  5695 
  5696 
  5697 New in Isabelle98 (January 1998)
  5698 --------------------------------
  5699 
  5700 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5701 
  5702 * changed lexical syntax of terms / types: dots made part of long
  5703 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5704 
  5705 * simpset (and claset) reference variable replaced by functions
  5706 simpset / simpset_ref;
  5707 
  5708 * no longer supports theory aliases (via merge) and non-trivial
  5709 implicit merge of thms' signatures;
  5710 
  5711 * most internal names of constants changed due to qualified names;
  5712 
  5713 * changed Pure/Sequence interface (see Pure/seq.ML);
  5714 
  5715 
  5716 *** General Changes ***
  5717 
  5718 * hierachically structured name spaces (for consts, types, axms, thms
  5719 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5720 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5721 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5722 long_names for fully qualified output names; NOTE: ML programs
  5723 (special tactics, packages etc.) referring to internal names may have
  5724 to be adapted to cope with fully qualified names; in case of severe
  5725 backward campatibility problems try setting 'global_names' at compile
  5726 time to have enrything declared within a flat name space; one may also
  5727 fine tune name declarations in theories via the 'global' and 'local'
  5728 section;
  5729 
  5730 * reimplemented the implicit simpset and claset using the new anytype
  5731 data filed in signatures; references simpset:simpset ref etc. are
  5732 replaced by functions simpset:unit->simpset and
  5733 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5734 to patch your ML files accordingly;
  5735 
  5736 * HTML output now includes theory graph data for display with Java
  5737 applet or isatool browser; data generated automatically via isatool
  5738 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5739 
  5740 * defs may now be conditional; improved rewrite_goals_tac to handle
  5741 conditional equations;
  5742 
  5743 * defs now admits additional type arguments, using TYPE('a) syntax;
  5744 
  5745 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5746 creates a new theory node; implicit merge of thms' signatures is
  5747 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5748 transfer:theory->thm->thm in (rare) cases;
  5749 
  5750 * improved handling of draft signatures / theories; draft thms (and
  5751 ctyps, cterms) are automatically promoted to real ones;
  5752 
  5753 * slightly changed interfaces for oracles: admit many per theory, named
  5754 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5755 
  5756 * print_goals: optional output of const types (set show_consts and
  5757 show_types);
  5758 
  5759 * improved output of warnings (###) and errors (***);
  5760 
  5761 * subgoal_tac displays a warning if the new subgoal has type variables;
  5762 
  5763 * removed old README and Makefiles;
  5764 
  5765 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5766 
  5767 * removed obsolete init_pps and init_database;
  5768 
  5769 * deleted the obsolete tactical STATE, which was declared by
  5770     fun STATE tacfun st = tacfun st st;
  5771 
  5772 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5773 (which abbreviates $HOME);
  5774 
  5775 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5776 use isatool fixseq to adapt your ML programs (this works for fully
  5777 qualified references to the Sequence structure only!);
  5778 
  5779 * use_thy no longer requires writable current directory; it always
  5780 reloads .ML *and* .thy file, if either one is out of date;
  5781 
  5782 
  5783 *** Classical Reasoner ***
  5784 
  5785 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5786 tactics that use classical reasoning to simplify a subgoal without
  5787 splitting it into several subgoals;
  5788 
  5789 * Safe_tac: like safe_tac but uses the default claset;
  5790 
  5791 
  5792 *** Simplifier ***
  5793 
  5794 * added simplification meta rules:
  5795     (asm_)(full_)simplify: simpset -> thm -> thm;
  5796 
  5797 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5798 logics (again);
  5799 
  5800 * added prems argument to simplification procedures;
  5801 
  5802 * HOL, FOL, ZF: added infix function `addsplits':
  5803   instead of `<simpset> setloop (split_tac <thms>)'
  5804   you can simply write `<simpset> addsplits <thms>'
  5805 
  5806 
  5807 *** Syntax ***
  5808 
  5809 * TYPE('a) syntax for type reflection terms;
  5810 
  5811 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5812 
  5813 * pretty printer: changed order of mixfix annotation preference (again!);
  5814 
  5815 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5816 
  5817 
  5818 *** HOL ***
  5819 
  5820 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5821   with `addloop' of the simplifier to faciliate case splitting in premises.
  5822 
  5823 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5824 
  5825 * HOL/Auth: new protocol proofs including some for the Internet
  5826   protocol TLS;
  5827 
  5828 * HOL/Map: new theory of `maps' a la VDM;
  5829 
  5830 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5831 cancelling out common nat summands from =, <, <= (in)equalities, or
  5832 differences; simplification procedures nat_cancel_factor for
  5833 cancelling common factor from =, <, <= (in)equalities over natural
  5834 sums; nat_cancel contains both kinds of procedures, it is installed by
  5835 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5836 
  5837 * HOL/simplifier: terms of the form
  5838   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5839   are rewritten to
  5840   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5841   and those of the form
  5842   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5843   are rewritten to
  5844   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5845 
  5846 * HOL/datatype
  5847   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5848 
  5849   P(t_case f1 ... fn x) =
  5850      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5851         ...
  5852        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5853      )
  5854 
  5855   and a theorem `split_t_case_asm' of the form
  5856 
  5857   P(t_case f1 ... fn x) =
  5858     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5859         ...
  5860        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5861      )
  5862   which can be added to a simpset via `addsplits'. The existing theorems
  5863   expand_list_case and expand_option_case have been renamed to
  5864   split_list_case and split_option_case.
  5865 
  5866 * HOL/Arithmetic:
  5867   - `pred n' is automatically converted to `n-1'.
  5868     Users are strongly encouraged not to use `pred' any longer,
  5869     because it will disappear altogether at some point.
  5870   - Users are strongly encouraged to write "0 < n" rather than
  5871     "n ~= 0". Theorems and proof tools have been modified towards this
  5872     `standard'.
  5873 
  5874 * HOL/Lists:
  5875   the function "set_of_list" has been renamed "set" (and its theorems too);
  5876   the function "nth" now takes its arguments in the reverse order and
  5877   has acquired the infix notation "!" as in "xs!n".
  5878 
  5879 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5880 
  5881 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5882   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5883 
  5884 * HOL/record: extensible records with schematic structural subtyping
  5885 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5886 still lacks various theorems and concrete record syntax;
  5887 
  5888 
  5889 *** HOLCF ***
  5890 
  5891 * removed "axioms" and "generated by" sections;
  5892 
  5893 * replaced "ops" section by extended "consts" section, which is capable of
  5894   handling the continuous function space "->" directly;
  5895 
  5896 * domain package:
  5897   . proves theorems immediately and stores them in the theory,
  5898   . creates hierachical name space,
  5899   . now uses normal mixfix annotations (instead of cinfix...),
  5900   . minor changes to some names and values (for consistency),
  5901   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5902   . separator between mutual domain defs: changed "," to "and",
  5903   . improved handling of sort constraints;  now they have to
  5904     appear on the left-hand side of the equations only;
  5905 
  5906 * fixed LAM <x,y,zs>.b syntax;
  5907 
  5908 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5909 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5910 
  5911 
  5912 *** FOL and ZF ***
  5913 
  5914 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5915   with `addloop' of the simplifier to faciliate case splitting in premises.
  5916 
  5917 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5918 in HOL, they strip ALL and --> from proved theorems;
  5919 
  5920 
  5921 
  5922 New in Isabelle94-8 (May 1997)
  5923 ------------------------------
  5924 
  5925 *** General Changes ***
  5926 
  5927 * new utilities to build / run / maintain Isabelle etc. (in parts
  5928 still somewhat experimental); old Makefiles etc. still functional;
  5929 
  5930 * new 'Isabelle System Manual';
  5931 
  5932 * INSTALL text, together with ./configure and ./build scripts;
  5933 
  5934 * reimplemented type inference for greater efficiency, better error
  5935 messages and clean internal interface;
  5936 
  5937 * prlim command for dealing with lots of subgoals (an easier way of
  5938 setting goals_limit);
  5939 
  5940 
  5941 *** Syntax ***
  5942 
  5943 * supports alternative (named) syntax tables (parser and pretty
  5944 printer); internal interface is provided by add_modesyntax(_i);
  5945 
  5946 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5947 be used in conjunction with the Isabelle symbol font; uses the
  5948 "symbols" syntax table;
  5949 
  5950 * added token_translation interface (may translate name tokens in
  5951 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5952 the current print_mode); IMPORTANT: user print translation functions
  5953 are responsible for marking newly introduced bounds
  5954 (Syntax.mark_boundT);
  5955 
  5956 * token translations for modes "xterm" and "xterm_color" that display
  5957 names in bold, underline etc. or colors (which requires a color
  5958 version of xterm);
  5959 
  5960 * infixes may now be declared with names independent of their syntax;
  5961 
  5962 * added typed_print_translation (like print_translation, but may
  5963 access type of constant);
  5964 
  5965 
  5966 *** Classical Reasoner ***
  5967 
  5968 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5969 some limitations.  Blast_tac...
  5970   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5971   + ignores elimination rules that don't have the correct format
  5972         (the conclusion MUST be a formula variable)
  5973   + ignores types, which can make HOL proofs fail
  5974   + rules must not require higher-order unification, e.g. apply_type in ZF
  5975     [message "Function Var's argument not a bound variable" relates to this]
  5976   + its proof strategy is more general but can actually be slower
  5977 
  5978 * substitution with equality assumptions no longer permutes other
  5979 assumptions;
  5980 
  5981 * minor changes in semantics of addafter (now called addaltern); renamed
  5982 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5983 (and access functions for it);
  5984 
  5985 * improved combination of classical reasoner and simplifier:
  5986   + functions for handling clasimpsets
  5987   + improvement of addss: now the simplifier is called _after_ the
  5988     safe steps.
  5989   + safe variant of addss called addSss: uses safe simplifications
  5990     _during_ the safe steps. It is more complete as it allows multiple
  5991     instantiations of unknowns (e.g. with slow_tac).
  5992 
  5993 *** Simplifier ***
  5994 
  5995 * added interface for simplification procedures (functions that
  5996 produce *proven* rewrite rules on the fly, depending on current
  5997 redex);
  5998 
  5999 * ordering on terms as parameter (used for ordered rewriting);
  6000 
  6001 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6002 
  6003 * the solver is now split into a safe and an unsafe part.
  6004 This should be invisible for the normal user, except that the
  6005 functions setsolver and addsolver have been renamed to setSolver and
  6006 addSolver; added safe_asm_full_simp_tac;
  6007 
  6008 
  6009 *** HOL ***
  6010 
  6011 * a generic induction tactic `induct_tac' which works for all datatypes and
  6012 also for type `nat';
  6013 
  6014 * a generic case distinction tactic `exhaust_tac' which works for all
  6015 datatypes and also for type `nat';
  6016 
  6017 * each datatype comes with a function `size';
  6018 
  6019 * patterns in case expressions allow tuple patterns as arguments to
  6020 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6021 
  6022 * primrec now also works with type nat;
  6023 
  6024 * recdef: a new declaration form, allows general recursive functions to be
  6025 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6026 
  6027 * the constant for negation has been renamed from "not" to "Not" to
  6028 harmonize with FOL, ZF, LK, etc.;
  6029 
  6030 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6031 infinite lists;
  6032 
  6033 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6034 
  6035 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6036 problems in commutative rings, using axiomatic type classes for + and *;
  6037 
  6038 * more examples in HOL/MiniML and HOL/Auth;
  6039 
  6040 * more default rewrite rules for quantifiers, union/intersection;
  6041 
  6042 * a new constant `arbitrary == @x.False';
  6043 
  6044 * HOLCF/IOA replaces old HOL/IOA;
  6045 
  6046 * HOLCF changes: derived all rules and arities
  6047   + axiomatic type classes instead of classes
  6048   + typedef instead of faking type definitions
  6049   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6050   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6051   + eliminated the types void, one, tr
  6052   + use unit lift and bool lift (with translations) instead of one and tr
  6053   + eliminated blift from Lift3.thy (use Def instead of blift)
  6054   all eliminated rules are derived as theorems --> no visible changes ;
  6055 
  6056 
  6057 *** ZF ***
  6058 
  6059 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6060 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6061 as ZF_cs addSIs [equalityI];
  6062 
  6063 
  6064 
  6065 New in Isabelle94-7 (November 96)
  6066 ---------------------------------
  6067 
  6068 * allowing negative levels (as offsets) in prlev and choplev;
  6069 
  6070 * super-linear speedup for large simplifications;
  6071 
  6072 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6073 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6074 FAIL); can suppress it using the command Delsimps (ex_simps @
  6075 all_simps); De Morgan laws are also now included, by default;
  6076 
  6077 * improved printing of ==>  :  ~:
  6078 
  6079 * new object-logic "Sequents" adds linear logic, while replacing LK
  6080 and Modal (thanks to Sara Kalvala);
  6081 
  6082 * HOL/Auth: correctness proofs for authentication protocols;
  6083 
  6084 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6085 examples on HOL/Auth);
  6086 
  6087 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6088 the rewriter and classical reasoner simultaneously;
  6089 
  6090 * function uresult no longer returns theorems in "standard" format;
  6091 regain previous version by: val uresult = standard o uresult;
  6092 
  6093 
  6094 
  6095 New in Isabelle94-6
  6096 -------------------
  6097 
  6098 * oracles -- these establish an interface between Isabelle and trusted
  6099 external reasoners, which may deliver results as theorems;
  6100 
  6101 * proof objects (in particular record all uses of oracles);
  6102 
  6103 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6104 
  6105 * "constdefs" section in theory files;
  6106 
  6107 * "primrec" section (HOL) no longer requires names;
  6108 
  6109 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6110 
  6111 
  6112 
  6113 New in Isabelle94-5
  6114 -------------------
  6115 
  6116 * reduced space requirements;
  6117 
  6118 * automatic HTML generation from theories;
  6119 
  6120 * theory files no longer require "..." (quotes) around most types;
  6121 
  6122 * new examples, including two proofs of the Church-Rosser theorem;
  6123 
  6124 * non-curried (1994) version of HOL is no longer distributed;
  6125 
  6126 
  6127 
  6128 New in Isabelle94-4
  6129 -------------------
  6130 
  6131 * greatly reduced space requirements;
  6132 
  6133 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6134 
  6135 * searchable theorem database (see the section "Retrieving theorems" on
  6136 page 8 of the Reference Manual);
  6137 
  6138 * new examples, including Grabczewski's monumental case study of the
  6139 Axiom of Choice;
  6140 
  6141 * The previous version of HOL renamed to Old_HOL;
  6142 
  6143 * The new version of HOL (previously called CHOL) uses a curried syntax
  6144 for functions.  Application looks like f a b instead of f(a,b);
  6145 
  6146 * Mutually recursive inductive definitions finally work in HOL;
  6147 
  6148 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6149 translates to the operator "split";
  6150 
  6151 
  6152 
  6153 New in Isabelle94-3
  6154 -------------------
  6155 
  6156 * new infix operator, addss, allowing the classical reasoner to
  6157 perform simplification at each step of its search.  Example:
  6158         fast_tac (cs addss ss)
  6159 
  6160 * a new logic, CHOL, the same as HOL, but with a curried syntax
  6161 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  6162 look like (a,b) instead of <a,b>;
  6163 
  6164 * PLEASE NOTE: CHOL will eventually replace HOL!
  6165 
  6166 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  6167 It translates to the operator "split".  A new theory of integers is available;
  6168 
  6169 * In ZF, integer numerals now denote two's-complement binary integers.
  6170 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  6171 
  6172 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  6173 of the Axiom of Choice;
  6174 
  6175 
  6176 
  6177 New in Isabelle94-2
  6178 -------------------
  6179 
  6180 * Significantly faster resolution;
  6181 
  6182 * the different sections in a .thy file can now be mixed and repeated
  6183 freely;
  6184 
  6185 * Database of theorems for FOL, HOL and ZF.  New
  6186 commands including qed, qed_goal and bind_thm store theorems in the database.
  6187 
  6188 * Simple database queries: return a named theorem (get_thm) or all theorems of
  6189 a given theory (thms_of), or find out what theory a theorem was proved in
  6190 (theory_of_thm);
  6191 
  6192 * Bugs fixed in the inductive definition and datatype packages;
  6193 
  6194 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  6195 and HOL_dup_cs obsolete;
  6196 
  6197 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  6198 have been removed;
  6199 
  6200 * Simpler definition of function space in ZF;
  6201 
  6202 * new results about cardinal and ordinal arithmetic in ZF;
  6203 
  6204 * 'subtype' facility in HOL for introducing new types as subsets of existing
  6205 types;
  6206 
  6207 :mode=text:wrap=hard:maxLineLen=72: