NEWS
author huffman
Mon Mar 16 15:58:41 2009 -0700 (2009-03-16)
changeset 30562 7b0017587e7d
parent 30547 4c2514625873
child 30577 79cc595655c0
permissions -rw-r--r--
document new additions to HOL/Library
     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 directly
   180 solve the current goal. Try "find_theorems solves".
   181 
   182 * Added an auto solve option, which can be enabled through the
   183 ProofGeneral Isabelle settings menu (disabled by default).
   184  
   185 When enabled, find_theorems solves is called whenever a new lemma is
   186 stated. Any theorems that could solve the lemma directly are listed
   187 underneath the goal.
   188 
   189 * New command 'find_consts' searches for constants based on type and
   190 name patterns, e.g.
   191 
   192     find_consts "_ => bool"
   193 
   194 By default, matching is against subtypes, but it may be restricted to
   195 the whole type. Searching by name is possible. Multiple queries are
   196 conjunctive and queries may be negated by prefixing them with a
   197 hyphen:
   198 
   199     find_consts strict: "_ => bool" name: "Int" -"int => int"
   200 
   201 * New command 'local_setup' is similar to 'setup', but operates on a
   202 local theory context.
   203 
   204 
   205 *** Document preparation ***
   206 
   207 * Antiquotation @{lemma} now imitates a regular terminal proof,
   208 demanding keyword 'by' and supporting the full method expression
   209 syntax just like the Isar command 'by'.
   210 
   211 
   212 *** HOL ***
   213 
   214 * Theory Library/Polynomial.thy defines an abstract type 'a poly of
   215 univariate polynomials with coefficients of type 'a.  In addition to
   216 the standard ring operations, it also supports div and mod.  Code
   217 generation is also supported, using list-style constructors.
   218 
   219 * Theory Library/Inner_Product.thy defines a class of real_inner for
   220 real inner product spaces, with an overloaded operation inner :: 'a =>
   221 'a => real.  Class real_inner is a subclass of real_normed_vector from
   222 RealVector.thy.
   223 
   224 * Theory Library/Product_Vector.thy provides instances for the product
   225 type 'a * 'b of several classes from RealVector.thy and
   226 Inner_Product.thy.  Definitions of addition, subtraction, scalar
   227 multiplication, norms, and inner products are included.
   228 
   229 * Theory Library/Bit.thy defines the field "bit" of integers modulo 2.
   230 In addition to the field operations, numerals and case syntax are also
   231 supported.
   232 
   233 * Theory Library/Diagonalize.thy provides constructive version of
   234 Cantor's first diagonalization argument.
   235 
   236 * New predicate "strict_mono" classifies strict functions on partial orders.
   237 With strict functions on linear orders, reasoning about (in)equalities is
   238 facilitated by theorems "strict_mono_eq", "strict_mono_less_eq" and "strict_mono_less".
   239 
   240 * Some set operations are now proper qualified constants with authentic syntax.
   241 INCOMPATIBILITY:
   242 
   243     op Int ~>   Set.Int
   244     op Un ~>    Set.Un
   245     INTER ~>    Set.INTER
   246     UNION ~>    Set.UNION
   247     Inter ~>    Set.Inter
   248     Union ~>    Set.Union
   249     {} ~>       Set.empty
   250     UNIV ~>     Set.UNIV
   251 
   252 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in theory
   253 Set.
   254 
   255 * Auxiliary class "itself" has disappeared -- classes without any parameter
   256 are treated as expected by the 'class' command.
   257 
   258 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   259 
   260 * Common decision procedures (Cooper, MIR, Ferrack, Approximation, Dense_Linear_Order)
   261 now in directory HOL/Decision_Procs.
   262 
   263 * Theory HOL/Decision_Procs/Approximation.thy provides the new proof method
   264 "approximation".  It proves formulas on real values by using interval arithmetic.
   265 In the formulas are also the transcendental functions sin, cos, tan, atan, ln,
   266 exp and the constant pi are allowed. For examples see
   267 HOL/Descision_Procs/ex/Approximation_Ex.thy.
   268 
   269 * Theory "Reflection" now resides in HOL/Library.
   270 
   271 * Entry point to Word library now simply named "Word".  INCOMPATIBILITY.
   272 
   273 * Made source layout more coherent with logical distribution
   274 structure:
   275 
   276     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   277     src/HOL/Library/Code_Message.thy ~> src/HOL/
   278     src/HOL/Library/GCD.thy ~> src/HOL/
   279     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   280     src/HOL/Library/Parity.thy ~> src/HOL/
   281     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   282     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   283     src/HOL/Real/Lubs.thy ~> src/HOL/
   284     src/HOL/Real/PReal.thy ~> src/HOL/
   285     src/HOL/Real/Rational.thy ~> src/HOL/
   286     src/HOL/Real/RComplete.thy ~> src/HOL/
   287     src/HOL/Real/RealDef.thy ~> src/HOL/
   288     src/HOL/Real/RealPow.thy ~> src/HOL/
   289     src/HOL/Real/Real.thy ~> src/HOL/
   290     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   291     src/HOL/Complex/Complex.thy ~> src/HOL/
   292     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   293     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   294     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   295     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   296     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   297     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   298     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   299     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   300     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   301     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   302     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   303     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   304     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   305     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   306     src/HOL/Real/Float ~> src/HOL/Library/
   307     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   308     src/HOL/Real/RealVector.thy ~> src/HOL/
   309 
   310     src/HOL/arith_data.ML ~> src/HOL/Tools
   311     src/HOL/hologic.ML ~> src/HOL/Tools
   312     src/HOL/simpdata.ML ~> src/HOL/Tools
   313     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   314     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   315     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   316     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   317     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   318     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   319     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   320 
   321     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   322     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   323     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   324     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   325     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   326     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   327 
   328 * If methods "eval" and "evaluation" encounter a structured proof state
   329 with !!/==>, only the conclusion is evaluated to True (if possible),
   330 avoiding strange error messages.
   331 
   332 * Simplifier: simproc for let expressions now unfolds if bound variable
   333 occurs at most once in let expression body.  INCOMPATIBILITY.
   334 
   335 * New classes "top" and "bot" with corresponding operations "top" and "bot"
   336 in theory Orderings;  instantiation of class "complete_lattice" requires
   337 instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   338 
   339 * Changed definition lemma "less_fun_def" in order to provide an instance
   340 for preorders on functions;  use lemma "less_le" instead.  INCOMPATIBILITY.
   341 
   342 * Unified theorem tables for both code code generators.  Thus
   343 [code func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   344 
   345 * Constants "undefined" and "default" replace "arbitrary".  Usually
   346 "undefined" is the right choice to replace "arbitrary", though logically
   347 there is no difference.  INCOMPATIBILITY.
   348 
   349 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   350 Posix processes.  Avoids potentially expensive forking of the ML
   351 process.  New thread-based implementation also works on non-Unix
   352 platforms (Cygwin).  Provers are no longer hardwired, but defined
   353 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   354 commands are covered in the isar-ref manual.
   355 
   356 * Wrapper scripts for remote SystemOnTPTP service allows to use
   357 sledgehammer without local ATP installation (Vampire etc.). Other
   358 provers may be included via suitable ML wrappers, see also
   359 src/HOL/ATP_Linkup.thy.
   360 
   361 * Normalization by evaluation now allows non-leftlinear equations.
   362 Declare with attribute [code nbe].
   363 
   364 * Command "value" now integrates different evaluation
   365 mechanisms.  The result of the first successful evaluation mechanism
   366 is printed.  In square brackets a particular named evaluation
   367 mechanisms may be specified (currently, [SML], [code] or [nbe]).  See
   368 further src/HOL/ex/Eval_Examples.thy.
   369 
   370 * New method "sizechange" to automate termination proofs using (a
   371 modification of) the size-change principle. Requires SAT solver. See
   372 src/HOL/ex/Termination.thy for examples.
   373 
   374 * HOL/Orderings: class "wellorder" moved here, with explicit induction
   375 rule "less_induct" as assumption.  For instantiation of "wellorder" by
   376 means of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.
   377 
   378 * HOL/Orderings: added class "preorder" as superclass of "order".
   379 INCOMPATIBILITY: Instantiation proofs for order, linorder
   380 etc. slightly changed.  Some theorems named order_class.* now named
   381 preorder_class.*.
   382 
   383 * HOL/Relation:
   384 Renamed "refl" to "refl_on", "reflexive" to "refl, "diag" to "Id_on".
   385 
   386 * HOL/Finite_Set: added a new fold combinator of type
   387   ('a => 'b => 'b) => 'b => 'a set => 'b
   388 Occasionally this is more convenient than the old fold combinator which is
   389 now defined in terms of the new one and renamed to fold_image.
   390 
   391 * HOL/Ring_and_Field and HOL/OrderedGroup: The lemmas "group_simps" and
   392 "ring_simps" have been replaced by "algebra_simps" (which can be extended with
   393 further lemmas!). At the moment both still exist but the former will disappear
   394 at some point.
   395 
   396 * HOL/Power: Lemma power_Suc is now declared as a simp rule in class
   397 recpower.  Type-specific simp rules for various recpower types have
   398 been removed.  INCOMPATIBILITY.  Rename old lemmas as follows:
   399 
   400 rat_power_0    -> power_0
   401 rat_power_Suc  -> power_Suc
   402 realpow_0      -> power_0
   403 realpow_Suc    -> power_Suc
   404 complexpow_0   -> power_0
   405 complexpow_Suc -> power_Suc
   406 power_poly_0   -> power_0
   407 power_poly_Suc -> power_Suc
   408 
   409 * HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
   410 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   411 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   412 of lemmas from Divides has been generalized from nat to class
   413 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   414 renames resulting from duplicate elimination:
   415 
   416     dvd_def_mod ~>          dvd_eq_mod_eq_0
   417     zero_dvd_iff ~>         dvd_0_left_iff
   418     dvd_0 ~>                dvd_0_right
   419     DIVISION_BY_ZERO_DIV ~> div_by_0
   420     DIVISION_BY_ZERO_MOD ~> mod_by_0
   421     mult_div ~>             div_mult_self2_is_id
   422     mult_mod ~>             mod_mult_self2_is_0
   423 
   424 * HOL/IntDiv: removed many lemmas that are instances of class-based
   425 generalizations (from Divides and Ring_and_Field).
   426 INCOMPATIBILITY. Rename old lemmas as follows:
   427 
   428 dvd_diff               -> nat_dvd_diff
   429 dvd_zminus_iff         -> dvd_minus_iff
   430 mod_add1_eq            -> mod_add_eq
   431 mod_mult1_eq           -> mod_mult_right_eq
   432 mod_mult1_eq'          -> mod_mult_left_eq
   433 mod_mult_distrib_mod   -> mod_mult_eq
   434 nat_mod_add_left_eq    -> mod_add_left_eq
   435 nat_mod_add_right_eq   -> mod_add_right_eq
   436 nat_mod_div_trivial    -> mod_div_trivial
   437 nat_mod_mod_trivial    -> mod_mod_trivial
   438 zdiv_zadd_self1        -> div_add_self1
   439 zdiv_zadd_self2        -> div_add_self2
   440 zdiv_zmult_self1       -> div_mult_self2_is_id
   441 zdiv_zmult_self2       -> div_mult_self1_is_id
   442 zdvd_triv_left         -> dvd_triv_left
   443 zdvd_triv_right        -> dvd_triv_right
   444 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   445 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   446 zmod_zadd_left_eq      -> mod_add_left_eq
   447 zmod_zadd_right_eq     -> mod_add_right_eq
   448 zmod_zadd_self1        -> mod_add_self1
   449 zmod_zadd_self2        -> mod_add_self2
   450 zmod_zadd1_eq          -> mod_add_eq
   451 zmod_zdiff1_eq         -> mod_diff_eq
   452 zmod_zdvd_zmod         -> mod_mod_cancel
   453 zmod_zmod_cancel       -> mod_mod_cancel
   454 zmod_zmult_self1       -> mod_mult_self2_is_0
   455 zmod_zmult_self2       -> mod_mult_self1_is_0
   456 zmod_1                 -> mod_by_1
   457 zdiv_1                 -> div_by_1
   458 zdvd_abs1              -> abs_dvd_iff
   459 zdvd_abs2              -> dvd_abs_iff
   460 zdvd_refl              -> dvd_refl
   461 zdvd_trans             -> dvd_trans
   462 zdvd_zadd              -> dvd_add
   463 zdvd_zdiff             -> dvd_diff
   464 zdvd_zminus_iff        -> dvd_minus_iff
   465 zdvd_zminus2_iff       -> minus_dvd_iff
   466 zdvd_zmultD            -> dvd_mult_right
   467 zdvd_zmultD2           -> dvd_mult_left
   468 zdvd_zmult_mono        -> mult_dvd_mono
   469 zdvd_0_right           -> dvd_0_right
   470 zdvd_0_left            -> dvd_0_left_iff
   471 zdvd_1_left            -> one_dvd
   472 zminus_dvd_iff         -> minus_dvd_iff
   473 
   474 * HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   475 zlcm (for int); carried together from various gcd/lcm developements in
   476 the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
   477 corresponding theorems renamed accordingly.  INCOMPATIBILITY.  To
   478 recover tupled syntax, use syntax declarations like:
   479 
   480     hide (open) const gcd
   481     abbreviation gcd where
   482       "gcd == (%(a, b). GCD.gcd a b)"
   483     notation (output)
   484       GCD.gcd ("gcd '(_, _')")
   485 
   486 (analogously for lcm, zgcd, zlcm).
   487 
   488 * HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   489 
   490 * The real numbers offer decimal input syntax: 12.34 is translated into
   491   1234/10^2. This translation is not reversed upon output.
   492 
   493 * New ML antiquotation @{code}: takes constant as argument, generates
   494 corresponding code in background and inserts name of the corresponding
   495 resulting ML value/function/datatype constructor binding in place.
   496 All occurrences of @{code} with a single ML block are generated
   497 simultaneously.  Provides a generic and safe interface for
   498 instrumentalizing code generation.  See HOL/ex/Code_Antiq for a toy
   499 example, or HOL/Complex/ex/ReflectedFerrack for a more ambitious
   500 application.  In future you ought refrain from ad-hoc compiling
   501 generated SML code on the ML toplevel.  Note that (for technical
   502 reasons) @{code} cannot refer to constants for which user-defined
   503 serializations are set.  Refer to the corresponding ML counterpart
   504 directly in that cases.
   505 
   506 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   507 Complex_Main.thy remain as they are.
   508 
   509 * New image HOL-Plain provides a minimal HOL with the most important
   510 tools available (inductive, datatype, primrec, ...).  By convention
   511 the corresponding theory Plain should be ancestor of every further
   512 (library) theory.  Some library theories now have ancestor Plain
   513 (instead of Main), thus theory Main occasionally has to be imported
   514 explicitly.
   515 
   516 * The metis method now fails in the usual manner, rather than raising
   517 an exception, if it determines that it cannot prove the theorem.
   518 
   519 * The metis method no longer fails because the theorem is too trivial
   520 (contains the empty clause).
   521 
   522 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   523 as the structured Isar versions "cases" and "induct", cf. the
   524 corresponding "cases" and "induct" attributes.  Mutual induction rules
   525 are now presented as a list of individual projections
   526 (e.g. foo_bar.inducts for types foo and bar); the old format with
   527 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   528 rare situations a different rule is selected --- notably nested tuple
   529 elimination instead of former prod.exhaust: use explicit (case_tac t
   530 rule: prod.exhaust) here.
   531 
   532 * Attributes "cases", "induct", "coinduct" support "del" option.
   533 
   534 * Removed fact "case_split_thm", which duplicates "case_split".
   535 
   536 * Command 'rep_datatype': instead of theorem names the command now
   537 takes a list of terms denoting the constructors of the type to be
   538 represented as datatype.  The characteristic theorems have to be
   539 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   540 have disappeared in favour of existing ones:
   541 
   542     unit_induct                 ~> unit.induct
   543     prod_induct                 ~> prod.induct
   544     sum_induct                  ~> sum.induct
   545     Suc_Suc_eq                  ~> nat.inject
   546     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   547 
   548 * The option datatype has been moved to a new theory HOL/Option.thy.
   549 Renamed option_map to Option.map, and o2s to Option.set.
   550 
   551 * Library/Nat_Infinity: added addition, numeral syntax and more
   552 instantiations for algebraic structures.  Removed some duplicate
   553 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   554 
   555 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   556 menu.
   557 
   558 * Linear arithmetic now ignores all inequalities when
   559 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   560 
   561 
   562 *** HOL-Algebra ***
   563 
   564 * New locales for orders and lattices where the equivalence relation
   565 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   566 locales use a record structure with field eq for the equivalence.
   567 
   568 * New theory of factorial domains.
   569 
   570 * Units_l_inv and Units_r_inv are now simprules by default.
   571 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   572 and/or r_inv will now also require deletion of these lemmas.
   573 
   574 * Renamed the following theorems.  INCOMPATIBILITY.
   575 UpperD ~> Upper_memD
   576 LowerD ~> Lower_memD
   577 least_carrier ~> least_closed
   578 greatest_carrier ~> greatest_closed
   579 greatest_Lower_above ~> greatest_Lower_below
   580 one_zero ~> carrier_one_zero
   581 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   582 
   583 
   584 *** HOL-NSA ***
   585 
   586 * Created new image HOL-NSA, containing theories of nonstandard
   587 analysis which were previously part of HOL-Complex.  Entry point
   588 Hyperreal.thy remains valid, but theories formerly using
   589 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   590 
   591 
   592 *** ZF ***
   593 
   594 * Proof of Zorn's Lemma for partial orders.
   595 
   596 
   597 *** HOLCF ***
   598 
   599 * Reimplemented the simplification procedure for proving continuity
   600 subgoals.  The new simproc is extensible; users can declare additional
   601 continuity introduction rules with the attribute [cont2cont].
   602 
   603 * The continuity simproc now uses a different introduction rule for
   604 solving continuity subgoals on terms with lambda abstractions.  In
   605 some rare cases the new simproc may fail to solve subgoals that the
   606 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   607 Potential INCOMPATIBILITY.
   608 
   609 * The syntax of the fixrec package has changed.  The specification
   610 syntax now conforms in style to definition, primrec, function, etc.
   611 See HOLCF/ex/Fixrec_ex.thy for examples.  INCOMPATIBILITY.
   612 
   613 
   614 *** ML ***
   615 
   616 * High-level support for concurrent ML programming, see
   617 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   618 particularly convenient to organize independent functional
   619 computations.  The concept of "synchronized variables" provides a
   620 higher-order interface for components with shared state, avoiding the
   621 delicate details of mutexes and condition variables.  [Poly/ML 5.2.1
   622 or later]
   623 
   624 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   625 and Method.setup, as well as commands 'attribute_setup' and
   626 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   627 existing code accordingly, or use plain 'setup' together with old
   628 Method.add_method.
   629 
   630 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   631 to 'a -> thm, while results are always tagged with an authentic oracle
   632 name.  The Isar command 'oracle' is now polymorphic, no argument type
   633 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   634 accordingly.  Note that extra performance may be gained by producing
   635 the cterm carefully, avoiding slow Thm.cterm_of.
   636 
   637 * ML bindings produced via Isar commands are stored within the Isar
   638 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   639 become thread-safe and work with undo as expected (concerning
   640 top-level bindings, not side-effects on global references).
   641 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   642 compiler at runtime; really global bindings need to be given outside a
   643 theory. [Poly/ML 5.2 or later]
   644 
   645 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   646 context. Top-level ML bindings are stored within the proof context in
   647 a purely sequential fashion, disregarding the nested proof structure.
   648 ML bindings introduced by 'ML_prf' are discarded at the end of the
   649 proof.  [Poly/ML 5.2 or later]
   650 
   651 * Generic Toplevel.add_hook interface allows to analyze the result of
   652 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   653 for theorem dependency output of transactions resulting in a new
   654 theory state.
   655 
   656 * More systematic treatment of long names, abstract name bindings, and
   657 name space operations.  Basic operations on qualified names have been
   658 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   659 Long_Name.append.  Old type bstring has been mostly replaced by
   660 abstract type binding (see structure Binding), which supports precise
   661 qualification (by packages and local theory targets), as well as
   662 proper tracking of source positions.  INCOMPATIBILITY, need to wrap
   663 old bstring values into Binding.name, or better pass through abstract
   664 bindings everywhere.  See further src/Pure/General/long_name.ML,
   665 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   666 
   667 * Simplified interface for defining document antiquotations via
   668 ThyOutput.antiquotation, ThyOutput.output, and optionally
   669 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   670 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   671 examples.
   672 
   673 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   674 LocalTheory.note etc.) now refer to the *full* internal name, not the
   675 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   676 
   677 * Rules and tactics that read instantiations (read_instantiate,
   678 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   679 context, which is required for parsing and type-checking.  Moreover,
   680 the variables are specified as plain indexnames, not string encodings
   681 thereof.  INCOMPATIBILITY.
   682 
   683 * Disposed old type and term read functions (Sign.read_def_typ,
   684 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   685 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   686 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   687 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   688 resort for legacy applications.
   689 
   690 * Antiquotations: block-structured compilation context indicated by
   691 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   692 
   693   @{let ?pat = term}                      - term abbreviation (HO matching)
   694   @{note name = fact}                     - fact abbreviation
   695   @{thm fact}                             - singleton fact (with attributes)
   696   @{thms fact}                            - general fact (with attributes)
   697   @{lemma prop by method}                 - singleton goal
   698   @{lemma prop by meth1 meth2}            - singleton goal
   699   @{lemma prop1 ... propN by method}      - general goal
   700   @{lemma prop1 ... propN by meth1 meth2} - general goal
   701   @{lemma (open) ...}                     - open derivation
   702 
   703 
   704 *** System ***
   705 
   706 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   707 Poly/ML 5.2.1 or later.
   708 
   709 * The Isabelle "emacs" tool provides a specific interface to invoke
   710 Proof General / Emacs, with more explicit failure if that is not
   711 installed (the old isabelle-interface script silently falls back on
   712 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   713 installation location of the Proof General distribution.
   714 
   715 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   716 the Isabelle process into a JVM/Scala application.  See
   717 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   718 process wrapper has been discontinued.)
   719 
   720 * Status messages (with exact source position information) are
   721 emitted, if proper markup print mode is enabled.  This allows
   722 user-interface components to provide detailed feedback on internal
   723 prover operations.
   724 
   725 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   726 
   727 
   728 
   729 New in Isabelle2008 (June 2008)
   730 -------------------------------
   731 
   732 *** General ***
   733 
   734 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   735 and updated, with formally checked references as hyperlinks.
   736 
   737 * Theory loader: use_thy (and similar operations) no longer set the
   738 implicit ML context, which was occasionally hard to predict and in
   739 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   740 provides a proper context already.
   741 
   742 * Theory loader: old-style ML proof scripts being *attached* to a thy
   743 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   744 'use' within a theory file will do the job.
   745 
   746 * Name space merge now observes canonical order, i.e. the second space
   747 is inserted into the first one, while existing entries in the first
   748 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   749 swap theory imports.
   750 
   751 * Syntax: symbol \<chi> is now considered a letter.  Potential
   752 INCOMPATIBILITY in identifier syntax etc.
   753 
   754 * Outer syntax: string tokens no longer admit escaped white space,
   755 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   756 white space without escapes.
   757 
   758 * Outer syntax: string tokens may contain arbitrary character codes
   759 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   760 "foo_bar".
   761 
   762 
   763 *** Pure ***
   764 
   765 * Context-dependent token translations.  Default setup reverts locally
   766 fixed variables, and adds hilite markup for undeclared frees.
   767 
   768 * Unused theorems can be found using the new command 'unused_thms'.
   769 There are three ways of invoking it:
   770 
   771 (1) unused_thms
   772      Only finds unused theorems in the current theory.
   773 
   774 (2) unused_thms thy_1 ... thy_n -
   775      Finds unused theorems in the current theory and all of its ancestors,
   776      excluding the theories thy_1 ... thy_n and all of their ancestors.
   777 
   778 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   779      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   780      their ancestors, excluding the theories thy_1 ... thy_n and all of
   781      their ancestors.
   782 
   783 In order to increase the readability of the list produced by
   784 unused_thms, theorems that have been created by a particular instance
   785 of a theory command such as 'inductive' or 'function' are considered
   786 to belong to the same "group", meaning that if at least one theorem in
   787 this group is used, the other theorems in the same group are no longer
   788 reported as unused.  Moreover, if all theorems in the group are
   789 unused, only one theorem in the group is displayed.
   790 
   791 Note that proof objects have to be switched on in order for
   792 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   793 usually the case when using Proof General with the default settings).
   794 
   795 * Authentic naming of facts disallows ad-hoc overwriting of previous
   796 theorems within the same name space.  INCOMPATIBILITY, need to remove
   797 duplicate fact bindings, or even accidental fact duplications.  Note
   798 that tools may maintain dynamically scoped facts systematically, using
   799 PureThy.add_thms_dynamic.
   800 
   801 * Command 'hide' now allows to hide from "fact" name space as well.
   802 
   803 * Eliminated destructive theorem database, simpset, claset, and
   804 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   805 update of theories within ML code.
   806 
   807 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   808 INCOMPATIBILITY, object-logics depending on former Pure require
   809 additional setup PureThy.old_appl_syntax_setup; object-logics
   810 depending on former CPure need to refer to Pure.
   811 
   812 * Commands 'use' and 'ML' are now purely functional, operating on
   813 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   814 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   815 INCOMPATIBILITY.
   816 
   817 * Command 'setup': discontinued implicit version with ML reference.
   818 
   819 * Instantiation target allows for simultaneous specification of class
   820 instance operations together with an instantiation proof.
   821 Type-checking phase allows to refer to class operations uniformly.
   822 See src/HOL/Complex/Complex.thy for an Isar example and
   823 src/HOL/Library/Eval.thy for an ML example.
   824 
   825 * Indexing of literal facts: be more serious about including only
   826 facts from the visible specification/proof context, but not the
   827 background context (locale etc.).  Affects `prop` notation and method
   828 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   829 situations.
   830 
   831 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   832 "(open)" option, which used to expose internal bound variables to the
   833 proof text.
   834 
   835 * Isar statements: removed obsolete case "rule_context".
   836 INCOMPATIBILITY, better use explicit fixes/assumes.
   837 
   838 * Locale proofs: default proof step now includes 'unfold_locales';
   839 hence 'proof' without argument may be used to unfold locale
   840 predicates.
   841 
   842 
   843 *** Document preparation ***
   844 
   845 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   846 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   847 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   848 spot); renamed link color from "darkblue" to "linkcolor" (default
   849 value unchanged, can be redefined via \definecolor); no longer sets
   850 "a4paper" option (unnecessary or even intrusive).
   851 
   852 * Antiquotation @{lemma A method} proves proposition A by the given
   853 method (either a method name or a method name plus (optional) method
   854 arguments in parentheses) and prints A just like @{prop A}.
   855 
   856 
   857 *** HOL ***
   858 
   859 * New primrec package.  Specification syntax conforms in style to
   860 definition/function/....  No separate induction rule is provided.  The
   861 "primrec" command distinguishes old-style and new-style specifications
   862 by syntax.  The former primrec package is now named OldPrimrecPackage.
   863 When adjusting theories, beware: constants stemming from new-style
   864 primrec specifications have authentic syntax.
   865 
   866 * Metis prover is now an order of magnitude faster, and also works
   867 with multithreading.
   868 
   869 * Metis: the maximum number of clauses that can be produced from a
   870 theorem is now given by the attribute max_clauses.  Theorems that
   871 exceed this number are ignored, with a warning printed.
   872 
   873 * Sledgehammer no longer produces structured proofs by default. To
   874 enable, declare [[sledgehammer_full = true]].  Attributes
   875 reconstruction_modulus, reconstruction_sorts renamed
   876 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   877 
   878 * Method "induct_scheme" derives user-specified induction rules
   879 from well-founded induction and completeness of patterns. This factors
   880 out some operations that are done internally by the function package
   881 and makes them available separately.  See
   882 src/HOL/ex/Induction_Scheme.thy for examples.
   883 
   884 * More flexible generation of measure functions for termination
   885 proofs: Measure functions can be declared by proving a rule of the
   886 form "is_measure f" and giving it the [measure_function] attribute.
   887 The "is_measure" predicate is logically meaningless (always true), and
   888 just guides the heuristic.  To find suitable measure functions, the
   889 termination prover sets up the goal "is_measure ?f" of the appropriate
   890 type and generates all solutions by prolog-style backwards proof using
   891 the declared rules.
   892 
   893 This setup also deals with rules like 
   894 
   895   "is_measure f ==> is_measure (list_size f)"
   896 
   897 which accommodates nested datatypes that recurse through lists.
   898 Similar rules are predeclared for products and option types.
   899 
   900 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   901 
   902   INCOMPATIBILITIES:
   903 
   904   - Definitions of overloaded constants on sets have to be replaced by
   905     definitions on => and bool.
   906 
   907   - Some definitions of overloaded operators on sets can now be proved
   908     using the definitions of the operators on => and bool.  Therefore,
   909     the following theorems have been renamed:
   910 
   911       subset_def   -> subset_eq
   912       psubset_def  -> psubset_eq
   913       set_diff_def -> set_diff_eq
   914       Compl_def    -> Compl_eq
   915       Sup_set_def  -> Sup_set_eq
   916       Inf_set_def  -> Inf_set_eq
   917       sup_set_def  -> sup_set_eq
   918       inf_set_def  -> inf_set_eq
   919 
   920   - Due to the incompleteness of the HO unification algorithm, some
   921     rules such as subst may require manual instantiation, if some of
   922     the unknowns in the rule is a set.
   923 
   924   - Higher order unification and forward proofs:
   925     The proof pattern
   926 
   927       have "P (S::'a set)" <...>
   928       then have "EX S. P S" ..
   929 
   930     no longer works (due to the incompleteness of the HO unification
   931     algorithm) and must be replaced by the pattern
   932 
   933       have "EX S. P S"
   934       proof
   935         show "P S" <...>
   936       qed
   937 
   938   - Calculational reasoning with subst (or similar rules):
   939     The proof pattern
   940 
   941       have "P (S::'a set)" <...>
   942       also have "S = T" <...>
   943       finally have "P T" .
   944 
   945     no longer works (for similar reasons as the previous example) and
   946     must be replaced by something like
   947 
   948       have "P (S::'a set)" <...>
   949       moreover have "S = T" <...>
   950       ultimately have "P T" by simp
   951 
   952   - Tactics or packages written in ML code:
   953     Code performing pattern matching on types via
   954 
   955       Type ("set", [T]) => ...
   956 
   957     must be rewritten. Moreover, functions like strip_type or
   958     binder_types no longer return the right value when applied to a
   959     type of the form
   960 
   961       T1 => ... => Tn => U => bool
   962 
   963     rather than
   964 
   965       T1 => ... => Tn => U set
   966 
   967 * Merged theories Wellfounded_Recursion, Accessible_Part and
   968 Wellfounded_Relations to theory Wellfounded.
   969 
   970 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   971 
   972 * Class finite no longer treats UNIV as class parameter.  Use class
   973 enum from theory Library/Enum instead to achieve a similar effect.
   974 INCOMPATIBILITY.
   975 
   976 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   977 and "Cons".  INCOMPATIBILITY.
   978 
   979 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   980 Potential INCOMPATIBILITY.
   981 
   982 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   983 injective_fst_snd removed, use split_eta and prod_eqI instead.
   984 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   985 
   986 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   987 the same name in theory Orderings:
   988 
   989   less_trans
   990   less_linear
   991   le_imp_less_or_eq
   992   le_less_trans
   993   less_le_trans
   994   less_not_sym
   995   less_asym
   996 
   997 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
   998 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
   999 and different variable names.
  1000 
  1001 * Library/Option_ord.thy: Canonical order on option type.
  1002 
  1003 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1004 finite maps.
  1005 
  1006 * Library/Countable.thy: Type class for countable types.
  1007 
  1008 * Theory Int: The representation of numerals has changed.  The infix
  1009 operator BIT and the bit datatype with constructors B0 and B1 have
  1010 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1011 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1012 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1013 accordingly.
  1014 
  1015 * Theory Nat: definition of <= and < on natural numbers no longer
  1016 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1017 le_def and less_def have disappeared.  Consider lemmas not_less
  1018 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1019 
  1020 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1021 (whose purpose mainly is for various fold_set functionals) have been
  1022 abandoned in favor of the existing algebraic classes
  1023 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1024 lower_semilattice (resp. upper_semilattice) and linorder.
  1025 INCOMPATIBILITY.
  1026 
  1027 * Theory Transitive_Closure: induct and cases rules now declare proper
  1028 case_names ("base" and "step").  INCOMPATIBILITY.
  1029 
  1030 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1031 lattices.  The form set-specific version is available as
  1032 Inductive.lfp_ordinal_induct_set.
  1033 
  1034 * Renamed theorems "power.simps" to "power_int.simps".
  1035 INCOMPATIBILITY.
  1036 
  1037 * Class semiring_div provides basic abstract properties of semirings
  1038 with division and modulo operations.  Subsumes former class dvd_mod.
  1039 
  1040 * Merged theories IntDef, Numeral and IntArith into unified theory
  1041 Int.  INCOMPATIBILITY.
  1042 
  1043 * Theory Library/Code_Index: type "index" now represents natural
  1044 numbers rather than integers.  INCOMPATIBILITY.
  1045 
  1046 * New class "uminus" with operation "uminus" (split of from class
  1047 "minus" which now only has operation "minus", binary).
  1048 INCOMPATIBILITY.
  1049 
  1050 * Constants "card", "internal_split", "option_map" now with authentic
  1051 syntax.  INCOMPATIBILITY.
  1052 
  1053 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1054 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1055 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1056 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1057 Sup_set_def, le_def, less_def, option_map_def now with object
  1058 equality.  INCOMPATIBILITY.
  1059 
  1060 * Records. Removed K_record, and replaced it by pure lambda term
  1061 %x. c. The simplifier setup is now more robust against eta expansion.
  1062 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1063 
  1064 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1065 
  1066 * Library/ListVector: new theory of arithmetic vector operations.
  1067 
  1068 * Library/Order_Relation: new theory of various orderings as sets of
  1069 pairs.  Defines preorders, partial orders, linear orders and
  1070 well-orders on sets and on types.
  1071 
  1072 
  1073 *** ZF ***
  1074 
  1075 * Renamed some theories to allow to loading both ZF and HOL in the
  1076 same session:
  1077 
  1078   Datatype  -> Datatype_ZF
  1079   Inductive -> Inductive_ZF
  1080   Int       -> Int_ZF
  1081   IntDiv    -> IntDiv_ZF
  1082   Nat       -> Nat_ZF
  1083   List      -> List_ZF
  1084   Main      -> Main_ZF
  1085 
  1086 INCOMPATIBILITY: ZF theories that import individual theories below
  1087 Main might need to be adapted.  Regular theory Main is still
  1088 available, as trivial extension of Main_ZF.
  1089 
  1090 
  1091 *** ML ***
  1092 
  1093 * ML within Isar: antiquotation @{const name} or @{const
  1094 name(typargs)} produces statically-checked Const term.
  1095 
  1096 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1097 (of the same name).  Removed obsolete print command.
  1098 
  1099 * Removed obsolete "use_legacy_bindings" function.
  1100 
  1101 * The ``print mode'' is now a thread-local value derived from a global
  1102 template (the former print_mode reference), thus access becomes
  1103 non-critical.  The global print_mode reference is for session
  1104 management only; user-code should use print_mode_value,
  1105 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1106 
  1107 * Functions system/system_out provide a robust way to invoke external
  1108 shell commands, with propagation of interrupts (requires Poly/ML
  1109 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1110 
  1111 
  1112 *** System ***
  1113 
  1114 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1115 in accordance with Proof General 3.7, which prefers GNU emacs.
  1116 
  1117 * isatool tty runs Isabelle process with plain tty interaction;
  1118 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1119 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1120 
  1121 * isatool browser now works with Cygwin as well, using general
  1122 "javapath" function defined in Isabelle process environment.
  1123 
  1124 * YXML notation provides a simple and efficient alternative to
  1125 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1126 isatool yxml as described in the Isabelle system manual.
  1127 
  1128 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1129 provides general wrapper for managing an Isabelle process in a robust
  1130 fashion, with ``cooked'' output from stdin/stderr.
  1131 
  1132 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1133 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1134 
  1135 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1136 way of changing the user's settings is via
  1137 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1138 script.
  1139 
  1140 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1141 cores of the underlying machine, which is a good starting point for
  1142 optimal performance tuning.  The corresponding usedir option -M allows
  1143 "max" as an alias for "0".  WARNING: does not work on certain versions
  1144 of Mac OS (with Poly/ML 5.1).
  1145 
  1146 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1147 adverse effect of Isabelle flooding interactive front-ends (notably
  1148 ProofGeneral / XEmacs).
  1149 
  1150 
  1151 
  1152 New in Isabelle2007 (November 2007)
  1153 -----------------------------------
  1154 
  1155 *** General ***
  1156 
  1157 * More uniform information about legacy features, notably a
  1158 warning/error of "Legacy feature: ...", depending on the state of the
  1159 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1160 legacy features will disappear eventually.
  1161 
  1162 * Theory syntax: the header format ``theory A = B + C:'' has been
  1163 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1164 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1165 
  1166 * Theory syntax: the old non-Isar theory file format has been
  1167 discontinued altogether.  Note that ML proof scripts may still be used
  1168 with Isar theories; migration is usually quite simple with the ML
  1169 function use_legacy_bindings.  INCOMPATIBILITY.
  1170 
  1171 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1172 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1173 quotes.
  1174 
  1175 * Theory loader: be more serious about observing the static theory
  1176 header specifications (including optional directories), but not the
  1177 accidental file locations of previously successful loads.  The strict
  1178 update policy of former update_thy is now already performed by
  1179 use_thy, so the former has been removed; use_thys updates several
  1180 theories simultaneously, just as 'imports' within a theory header
  1181 specification, but without merging the results.  Potential
  1182 INCOMPATIBILITY: may need to refine theory headers and commands
  1183 ROOT.ML which depend on load order.
  1184 
  1185 * Theory loader: optional support for content-based file
  1186 identification, instead of the traditional scheme of full physical
  1187 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1188 (cf. the system manual).  The new scheme allows to work with
  1189 non-finished theories in persistent session images, such that source
  1190 files may be moved later on without requiring reloads.
  1191 
  1192 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1193 file (with the same base name as the theory) are considered a legacy
  1194 feature, which will disappear eventually. Even now, the theory loader
  1195 no longer maintains dependencies on such files.
  1196 
  1197 * Syntax: the scope for resolving ambiguities via type-inference is
  1198 now limited to individual terms, instead of whole simultaneous
  1199 specifications as before. This greatly reduces the complexity of the
  1200 syntax module and improves flexibility by separating parsing and
  1201 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1202 'fixes' etc.) are required in rare situations.
  1203 
  1204 * Syntax: constants introduced by new-style packages ('definition',
  1205 'abbreviation' etc.) are passed through the syntax module in
  1206 ``authentic mode''. This means that associated mixfix annotations
  1207 really stick to such constants, independently of potential name space
  1208 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1209 trees are represented slightly differently, may need to adapt syntax
  1210 translations accordingly. Use CONST marker in 'translations' and
  1211 @{const_syntax} antiquotation in 'parse_translation' etc.
  1212 
  1213 * Legacy goal package: reduced interface to the bare minimum required
  1214 to keep existing proof scripts running.  Most other user-level
  1215 functions are now part of the OldGoals structure, which is *not* open
  1216 by default (consider isatool expandshort before open OldGoals).
  1217 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1218 these tend to cause confusion about the actual goal (!) context being
  1219 used here, which is not necessarily the same as the_context().
  1220 
  1221 * Command 'find_theorems': supports "*" wild-card in "name:"
  1222 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1223 support a specific search form (see ProofGeneral/CHANGES).
  1224 
  1225 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1226 by default, which means that "prems" (and also "fixed variables") are
  1227 suppressed from proof state output.  Note that the ProofGeneral
  1228 settings mechanism allows to change and save options persistently, but
  1229 older versions of Isabelle will fail to start up if a negative prems
  1230 limit is imposed.
  1231 
  1232 * Local theory targets may be specified by non-nested blocks of
  1233 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1234 contain definitions, theorems etc., including any derived mechanism
  1235 that has been implemented on top of these primitives.  This concept
  1236 generalizes the existing ``theorem (in ...)'' towards more versatility
  1237 and scalability.
  1238 
  1239 * Proof General interface: proper undo of final 'end' command;
  1240 discontinued Isabelle/classic mode (ML proof scripts).
  1241 
  1242 
  1243 *** Document preparation ***
  1244 
  1245 * Added antiquotation @{theory name} which prints the given name,
  1246 after checking that it refers to a valid ancestor theory in the
  1247 current context.
  1248 
  1249 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1250 check the given source text as ML type/structure, printing verbatim.
  1251 
  1252 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1253 "c args == rhs" given in the current context.  (Any number of
  1254 arguments may be given on the LHS.)
  1255 
  1256 
  1257 *** Pure ***
  1258 
  1259 * The 'class' package offers a combination of axclass and locale to
  1260 achieve Haskell-like type classes in Isabelle.  Definitions and
  1261 theorems within a class context produce both relative results (with
  1262 implicit parameters according to the locale context), and polymorphic
  1263 constants with qualified polymorphism (according to the class
  1264 context).  Within the body context of a 'class' target, a separate
  1265 syntax layer ("user space type system") takes care of converting
  1266 between global polymorphic consts and internal locale representation.
  1267 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1268 "isatool doc classes" provides a tutorial.
  1269 
  1270 * Generic code generator framework allows to generate executable
  1271 code for ML and Haskell (including Isabelle classes).  A short usage
  1272 sketch:
  1273 
  1274     internal compilation:
  1275         export_code <list of constants (term syntax)> in SML
  1276     writing SML code to a file:
  1277         export_code <list of constants (term syntax)> in SML <filename>
  1278     writing OCaml code to a file:
  1279         export_code <list of constants (term syntax)> in OCaml <filename>
  1280     writing Haskell code to a bunch of files:
  1281         export_code <list of constants (term syntax)> in Haskell <filename>
  1282 
  1283     evaluating closed propositions to True/False using code generation:
  1284         method ``eval''
  1285 
  1286 Reasonable default setup of framework in HOL.
  1287 
  1288 Theorem attributs for selecting and transforming function equations theorems:
  1289 
  1290     [code fun]:        select a theorem as function equation for a specific constant
  1291     [code fun del]:    deselect a theorem as function equation for a specific constant
  1292     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1293     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1294 
  1295 User-defined serializations (target in {SML, OCaml, Haskell}):
  1296 
  1297     code_const <and-list of constants (term syntax)>
  1298       {(target) <and-list of const target syntax>}+
  1299 
  1300     code_type <and-list of type constructors>
  1301       {(target) <and-list of type target syntax>}+
  1302 
  1303     code_instance <and-list of instances>
  1304       {(target)}+
  1305         where instance ::= <type constructor> :: <class>
  1306 
  1307     code_class <and_list of classes>
  1308       {(target) <and-list of class target syntax>}+
  1309         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1310 
  1311 code_instance and code_class only are effective to target Haskell.
  1312 
  1313 For example usage see src/HOL/ex/Codegenerator.thy and
  1314 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1315 generation from Isabelle/HOL theories is available via "isatool doc
  1316 codegen".
  1317 
  1318 * Code generator: consts in 'consts_code' Isar commands are now
  1319 referred to by usual term syntax (including optional type
  1320 annotations).
  1321 
  1322 * Command 'no_translations' removes translation rules from theory
  1323 syntax.
  1324 
  1325 * Overloaded definitions are now actually checked for acyclic
  1326 dependencies.  The overloading scheme is slightly more general than
  1327 that of Haskell98, although Isabelle does not demand an exact
  1328 correspondence to type class and instance declarations.
  1329 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1330 exotic versions of overloading -- at the discretion of the user!
  1331 
  1332 Polymorphic constants are represented via type arguments, i.e. the
  1333 instantiation that matches an instance against the most general
  1334 declaration given in the signature.  For example, with the declaration
  1335 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1336 as c(nat).  Overloading is essentially simultaneous structural
  1337 recursion over such type arguments.  Incomplete specification patterns
  1338 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1339 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1340 Command 'print_theory' outputs the normalized system of recursive
  1341 equations, see section "definitions".
  1342 
  1343 * Configuration options are maintained within the theory or proof
  1344 context (with name and type bool/int/string), providing a very simple
  1345 interface to a poor-man's version of general context data.  Tools may
  1346 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1347 these values using Config.get etc.  Users may change options via an
  1348 associated attribute of the same name.  This form of context
  1349 declaration works particularly well with commands 'declare' or
  1350 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1351 very easy to avoid global references, which would not observe Isar
  1352 toplevel undo/redo and fail to work with multithreading.
  1353 
  1354 Various global ML references of Pure and HOL have been turned into
  1355 configuration options:
  1356 
  1357   Unify.search_bound		unify_search_bound
  1358   Unify.trace_bound		unify_trace_bound
  1359   Unify.trace_simp		unify_trace_simp
  1360   Unify.trace_types		unify_trace_types
  1361   Simplifier.simp_depth_limit	simp_depth_limit
  1362   Blast.depth_limit		blast_depth_limit
  1363   DatatypeProp.dtK		datatype_distinctness_limit
  1364   fast_arith_neq_limit  	fast_arith_neq_limit
  1365   fast_arith_split_limit	fast_arith_split_limit
  1366 
  1367 * Named collections of theorems may be easily installed as context
  1368 data using the functor NamedThmsFun (see also
  1369 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1370 attributes; there is also a toplevel print command.  This facility is
  1371 just a common case of general context data, which is the preferred way
  1372 for anything more complex than just a list of facts in canonical
  1373 order.
  1374 
  1375 * Isar: command 'declaration' augments a local theory by generic
  1376 declaration functions written in ML.  This enables arbitrary content
  1377 being added to the context, depending on a morphism that tells the
  1378 difference of the original declaration context wrt. the application
  1379 context encountered later on.
  1380 
  1381 * Isar: proper interfaces for simplification procedures.  Command
  1382 'simproc_setup' declares named simprocs (with match patterns, and body
  1383 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1384 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1385 
  1386 * Isar: an extra pair of brackets around attribute declarations
  1387 abbreviates a theorem reference involving an internal dummy fact,
  1388 which will be ignored later --- only the effect of the attribute on
  1389 the background context will persist.  This form of in-place
  1390 declarations is particularly useful with commands like 'declare' and
  1391 'using', for example ``have A using [[simproc a]] by simp''.
  1392 
  1393 * Isar: method "assumption" (and implicit closing of subproofs) now
  1394 takes simple non-atomic goal assumptions into account: after applying
  1395 an assumption as a rule the resulting subgoals are solved by atomic
  1396 assumption steps.  This is particularly useful to finish 'obtain'
  1397 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1398 without referring to the original premise "!!x. P x ==> thesis" in the
  1399 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1400 more permissive.
  1401 
  1402 * Isar: implicit use of prems from the Isar proof context is
  1403 considered a legacy feature.  Common applications like ``have A .''
  1404 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1405 referencing facts explicitly here improves readability and
  1406 maintainability of proof texts.
  1407 
  1408 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1409 the obtained context from the course of reasoning!  For example:
  1410 
  1411   assume "EX x y. A x & B y"   -- "any previous fact"
  1412   then guess x and y by clarify
  1413 
  1414 This technique is potentially adventurous, depending on the facts and
  1415 proof tools being involved here.
  1416 
  1417 * Isar: known facts from the proof context may be specified as literal
  1418 propositions, using ASCII back-quote syntax.  This works wherever
  1419 named facts used to be allowed so far, in proof commands, proof
  1420 methods, attributes etc.  Literal facts are retrieved from the context
  1421 according to unification of type and term parameters.  For example,
  1422 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1423 theorems in the current context, then these are valid literal facts:
  1424 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1425 
  1426 There is also a proof method "fact" which does the same composition
  1427 for explicit goal states, e.g. the following proof texts coincide with
  1428 certain special cases of literal facts:
  1429 
  1430   have "A" by fact                 ==  note `A`
  1431   have "A ==> B" by fact           ==  note `A ==> B`
  1432   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1433   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1434 
  1435 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1436 outer syntax.  Thus symbolic identifiers may be used without
  1437 additional white space in declarations like this: ``assume *: A''.
  1438 
  1439 * Isar: 'print_facts' prints all local facts of the current context,
  1440 both named and unnamed ones.
  1441 
  1442 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1443 
  1444   def x == "t" and y == "u"
  1445 
  1446 * Isar: added command 'unfolding', which is structurally similar to
  1447 'using', but affects both the goal state and facts by unfolding given
  1448 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1449 'unfolded' attribute may be replaced by first-class proof text.
  1450 
  1451 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1452 and command 'unfolding' now all support object-level equalities
  1453 (potentially conditional).  The underlying notion of rewrite rule is
  1454 analogous to the 'rule_format' attribute, but *not* that of the
  1455 Simplifier (which is usually more generous).
  1456 
  1457 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1458 premises of a theorem by n. Useful in conjunction with drule.
  1459 
  1460 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1461 method expression within a sandbox consisting of the first N
  1462 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1463 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1464 simplifies all new goals that emerge from applying rule foo to the
  1465 originally first one.
  1466 
  1467 * Isar: schematic goals are no longer restricted to higher-order
  1468 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1469 expected.
  1470 
  1471 * Isar: the conclusion of a long theorem statement is now either
  1472 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1473 (essentially a disjunction of cases with local parameters and
  1474 assumptions).  The latter allows to express general elimination rules
  1475 adequately; in this notation common elimination rules look like this:
  1476 
  1477   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1478     assumes "EX x. P x"
  1479     obtains x where "P x"
  1480 
  1481   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1482     assumes "A & B"
  1483     obtains A and B
  1484 
  1485   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1486     assumes "A | B"
  1487     obtains
  1488       A
  1489     | B
  1490 
  1491 The subsequent classical rules even refer to the formal "thesis"
  1492 explicitly:
  1493 
  1494   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1495     obtains "~ thesis"
  1496 
  1497   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1498     obtains "thesis ==> something"
  1499 
  1500 The actual proof of an 'obtains' statement is analogous to that of the
  1501 Isar proof element 'obtain', only that there may be several cases.
  1502 Optional case names may be specified in parentheses; these will be
  1503 available both in the present proof and as annotations in the
  1504 resulting rule, for later use with the 'cases' method (cf. attribute
  1505 case_names).
  1506 
  1507 * Isar: the assumptions of a long theorem statement are available as
  1508 "assms" fact in the proof context.  This is more appropriate than the
  1509 (historical) "prems", which refers to all assumptions of the current
  1510 context, including those from the target locale, proof body etc.
  1511 
  1512 * Isar: 'print_statement' prints theorems from the current theory or
  1513 proof context in long statement form, according to the syntax of a
  1514 top-level lemma.
  1515 
  1516 * Isar: 'obtain' takes an optional case name for the local context
  1517 introduction rule (default "that").
  1518 
  1519 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1520 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1521 to occur.
  1522 
  1523 * Pure: syntax "CONST name" produces a fully internalized constant
  1524 according to the current context.  This is particularly useful for
  1525 syntax translations that should refer to internal constant
  1526 representations independently of name spaces.
  1527 
  1528 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1529 instead of "FOO ". This allows multiple binder declarations to coexist
  1530 in the same context.  INCOMPATIBILITY.
  1531 
  1532 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1533 primitive that also works in a locale context (both for constants and
  1534 fixed variables). Type declaration and internal syntactic representation
  1535 of given constants retrieved from the context. Likewise, the
  1536 'no_notation' command allows to remove given syntax annotations from the
  1537 current context.
  1538 
  1539 * Isar/locales: new derived specification elements 'axiomatization',
  1540 'definition', 'abbreviation', which support type-inference, admit
  1541 object-level specifications (equality, equivalence).  See also the
  1542 isar-ref manual.  Examples:
  1543 
  1544   axiomatization
  1545     eq  (infix "===" 50) where
  1546     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1547 
  1548   definition "f x y = x + y + 1"
  1549   definition g where "g x = f x x"
  1550 
  1551   abbreviation
  1552     neq  (infix "=!=" 50) where
  1553     "x =!= y == ~ (x === y)"
  1554 
  1555 These specifications may be also used in a locale context.  Then the
  1556 constants being introduced depend on certain fixed parameters, and the
  1557 constant name is qualified by the locale base name.  An internal
  1558 abbreviation takes care for convenient input and output, making the
  1559 parameters implicit and using the original short name.  See also
  1560 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1561 entities from a monomorphic theory.
  1562 
  1563 Presently, abbreviations are only available 'in' a target locale, but
  1564 not inherited by general import expressions.  Also note that
  1565 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1566 'translations' in common applications.  The "no_abbrevs" print mode
  1567 prevents folding of abbreviations in term output.
  1568 
  1569 Concrete syntax is attached to specified constants in internal form,
  1570 independently of name spaces.  The parse tree representation is
  1571 slightly different -- use 'notation' instead of raw 'syntax', and
  1572 'translations' with explicit "CONST" markup to accommodate this.
  1573 
  1574 * Pure/Isar: unified syntax for new-style specification mechanisms
  1575 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1576 full type inference and dummy patterns ("_").  For example:
  1577 
  1578   definition "K x _ = x"
  1579 
  1580   inductive conj for A B
  1581   where "A ==> B ==> conj A B"
  1582 
  1583 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1584 the current context.  Print mode "no_abbrevs" prevents inversion of
  1585 abbreviations on output.
  1586 
  1587 * Isar/locales: improved parameter handling: use of locales "var" and
  1588 "struct" no longer necessary; - parameter renamings are no longer
  1589 required to be injective.  For example, this allows to define
  1590 endomorphisms as locale endom = homom mult mult h.
  1591 
  1592 * Isar/locales: changed the way locales with predicates are defined.
  1593 Instead of accumulating the specification, the imported expression is
  1594 now an interpretation.  INCOMPATIBILITY: different normal form of
  1595 locale expressions.  In particular, in interpretations of locales with
  1596 predicates, goals repesenting already interpreted fragments are not
  1597 removed automatically.  Use methods `intro_locales' and
  1598 `unfold_locales'; see below.
  1599 
  1600 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1601 provide backward reasoning on locales predicates.  The methods are
  1602 aware of interpretations and discharge corresponding goals.
  1603 `intro_locales' is less aggressive then `unfold_locales' and does not
  1604 unfold predicates to assumptions.
  1605 
  1606 * Isar/locales: the order in which locale fragments are accumulated
  1607 has changed.  This enables to override declarations from fragments due
  1608 to interpretations -- for example, unwanted simp rules.
  1609 
  1610 * Isar/locales: interpretation in theories and proof contexts has been
  1611 extended.  One may now specify (and prove) equations, which are
  1612 unfolded in interpreted theorems.  This is useful for replacing
  1613 defined concepts (constants depending on locale parameters) by
  1614 concepts already existing in the target context.  Example:
  1615 
  1616   interpretation partial_order ["op <= :: [int, int] => bool"]
  1617     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1618 
  1619 Typically, the constant `partial_order.less' is created by a
  1620 definition specification element in the context of locale
  1621 partial_order.
  1622 
  1623 * Method "induct": improved internal context management to support
  1624 local fixes and defines on-the-fly. Thus explicit meta-level
  1625 connectives !!  and ==> are rarely required anymore in inductive goals
  1626 (using object-logic connectives for this purpose has been long
  1627 obsolete anyway). Common proof patterns are explained in
  1628 src/HOL/Induct/Common_Patterns.thy, see also
  1629 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1630 examples.
  1631 
  1632 * Method "induct": improved handling of simultaneous goals. Instead of
  1633 introducing object-level conjunction, the statement is now split into
  1634 several conclusions, while the corresponding symbolic cases are nested
  1635 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1636 see src/HOL/Induct/Common_Patterns.thy, for example.
  1637 
  1638 * Method "induct": mutual induction rules are now specified as a list
  1639 of rule sharing the same induction cases. HOL packages usually provide
  1640 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1641 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1642 mutual induction rules differently, i.e. like this:
  1643 
  1644   (induct rule: foo_bar.inducts)
  1645   (induct set: foo bar)
  1646   (induct pred: foo bar)
  1647   (induct type: foo bar)
  1648 
  1649 The ML function ProjectRule.projections turns old-style rules into the
  1650 new format.
  1651 
  1652 * Method "coinduct": dual of induction, see
  1653 src/HOL/Library/Coinductive_List.thy for various examples.
  1654 
  1655 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1656 considered a legacy feature.
  1657 
  1658 * Attribute "symmetric" produces result with standardized schematic
  1659 variables (index 0).  Potential INCOMPATIBILITY.
  1660 
  1661 * Simplifier: by default the simplifier trace only shows top level
  1662 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1663 default. Thus there is less danger of being flooded by the trace. The
  1664 trace indicates where parts have been suppressed.
  1665   
  1666 * Provers/classical: removed obsolete classical version of elim_format
  1667 attribute; classical elim/dest rules are now treated uniformly when
  1668 manipulating the claset.
  1669 
  1670 * Provers/classical: stricter checks to ensure that supplied intro,
  1671 dest and elim rules are well-formed; dest and elim rules must have at
  1672 least one premise.
  1673 
  1674 * Provers/classical: attributes dest/elim/intro take an optional
  1675 weight argument for the rule (just as the Pure versions).  Weights are
  1676 ignored by automated tools, but determine the search order of single
  1677 rule steps.
  1678 
  1679 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1680 where the body does not mention the bound variable.  Note that dummy
  1681 patterns implicitly depend on their context of bounds, which makes
  1682 "{_. _}" match any set comprehension as expected.  Potential
  1683 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1684 constant "_idtdummy" in the binding position.
  1685 
  1686 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1687 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1688 for example "A -> B" => "Pi A (%_. B)".
  1689 
  1690 * Pure: 'class_deps' command visualizes the subclass relation, using
  1691 the graph browser tool.
  1692 
  1693 * Pure: 'print_theory' now suppresses certain internal declarations by
  1694 default; use '!' option for full details.
  1695 
  1696 
  1697 *** HOL ***
  1698 
  1699 * Method "metis" proves goals by applying the Metis general-purpose
  1700 resolution prover (see also http://gilith.com/software/metis/).
  1701 Examples are in the directory MetisExamples.  WARNING: the
  1702 Isabelle/HOL-Metis integration does not yet work properly with
  1703 multi-threading.
  1704   
  1705 * Command 'sledgehammer' invokes external automatic theorem provers as
  1706 background processes.  It generates calls to the "metis" method if
  1707 successful. These can be pasted into the proof.  Users do not have to
  1708 wait for the automatic provers to return.  WARNING: does not really
  1709 work with multi-threading.
  1710 
  1711 * New "auto_quickcheck" feature tests outermost goal statements for
  1712 potential counter-examples.  Controlled by ML references
  1713 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1714 5000 milliseconds).  Fails silently if statements is outside of
  1715 executable fragment, or any other codgenerator problem occurs.
  1716 
  1717 * New constant "undefined" with axiom "undefined x = undefined".
  1718 
  1719 * Added class "HOL.eq", allowing for code generation with polymorphic
  1720 equality.
  1721 
  1722 * Some renaming of class constants due to canonical name prefixing in
  1723 the new 'class' package:
  1724 
  1725     HOL.abs ~> HOL.abs_class.abs
  1726     HOL.divide ~> HOL.divide_class.divide
  1727     0 ~> HOL.zero_class.zero
  1728     1 ~> HOL.one_class.one
  1729     op + ~> HOL.plus_class.plus
  1730     op - ~> HOL.minus_class.minus
  1731     uminus ~> HOL.minus_class.uminus
  1732     op * ~> HOL.times_class.times
  1733     op < ~> HOL.ord_class.less
  1734     op <= > HOL.ord_class.less_eq
  1735     Nat.power ~> Power.power_class.power
  1736     Nat.size ~> Nat.size_class.size
  1737     Numeral.number_of ~> Numeral.number_class.number_of
  1738     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1739     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1740     Orderings.min ~> Orderings.ord_class.min
  1741     Orderings.max ~> Orderings.ord_class.max
  1742     Divides.op div ~> Divides.div_class.div
  1743     Divides.op mod ~> Divides.div_class.mod
  1744     Divides.op dvd ~> Divides.div_class.dvd
  1745 
  1746 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1747 
  1748 a) User-defined constants using any of the names "plus", "minus",
  1749 "times", "less" or "less_eq". The standard syntax translations for
  1750 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1751 names.
  1752 
  1753 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1754 INCOMPATIBILITY: use more specific names.
  1755 
  1756 c) Permutative equations (e.g. "a + b = b + a")
  1757 Since the change of names also changes the order of terms, permutative
  1758 rewrite rules may get applied in a different order. Experience shows
  1759 that this is rarely the case (only two adaptions in the whole Isabelle
  1760 distribution).  INCOMPATIBILITY: rewrite proofs
  1761 
  1762 d) ML code directly refering to constant names
  1763 This in general only affects hand-written proof tactics, simprocs and
  1764 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1765 Consider using @{const_name} antiquotation.
  1766 
  1767 * New class "default" with associated constant "default".
  1768 
  1769 * Function "sgn" is now overloaded and available on int, real, complex
  1770 (and other numeric types), using class "sgn".  Two possible defs of
  1771 sgn are given as equational assumptions in the classes sgn_if and
  1772 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1773 INCOMPATIBILITY.
  1774 
  1775 * Locale "partial_order" now unified with class "order" (cf. theory
  1776 Orderings), added parameter "less".  INCOMPATIBILITY.
  1777 
  1778 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1779 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1780 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1781 
  1782 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1783 changed order of proof goals in instance proofs.
  1784 
  1785 * The transitivity reasoner for partial and linear orders is set up
  1786 for classes "order" and "linorder".  Instances of the reasoner are available
  1787 in all contexts importing or interpreting the corresponding locales.
  1788 Method "order" invokes the reasoner separately; the reasoner
  1789 is also integrated with the Simplifier as a solver.  Diagnostic
  1790 command 'print_orders' shows the available instances of the reasoner
  1791 in the current context.
  1792 
  1793 * Localized monotonicity predicate in theory "Orderings"; integrated
  1794 lemmas max_of_mono and min_of_mono with this predicate.
  1795 INCOMPATIBILITY.
  1796 
  1797 * Formulation of theorem "dense" changed slightly due to integration
  1798 with new class dense_linear_order.
  1799 
  1800 * Uniform lattice theory development in HOL.
  1801 
  1802     constants "meet" and "join" now named "inf" and "sup"
  1803     constant "Meet" now named "Inf"
  1804 
  1805     classes "meet_semilorder" and "join_semilorder" now named
  1806       "lower_semilattice" and "upper_semilattice"
  1807     class "lorder" now named "lattice"
  1808     class "comp_lat" now named "complete_lattice"
  1809 
  1810     Instantiation of lattice classes allows explicit definitions
  1811     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1812 
  1813   INCOMPATIBILITY.  Theorem renames:
  1814 
  1815     meet_left_le            ~> inf_le1
  1816     meet_right_le           ~> inf_le2
  1817     join_left_le            ~> sup_ge1
  1818     join_right_le           ~> sup_ge2
  1819     meet_join_le            ~> inf_sup_ord
  1820     le_meetI                ~> le_infI
  1821     join_leI                ~> le_supI
  1822     le_meet                 ~> le_inf_iff
  1823     le_join                 ~> ge_sup_conv
  1824     meet_idempotent         ~> inf_idem
  1825     join_idempotent         ~> sup_idem
  1826     meet_comm               ~> inf_commute
  1827     join_comm               ~> sup_commute
  1828     meet_leI1               ~> le_infI1
  1829     meet_leI2               ~> le_infI2
  1830     le_joinI1               ~> le_supI1
  1831     le_joinI2               ~> le_supI2
  1832     meet_assoc              ~> inf_assoc
  1833     join_assoc              ~> sup_assoc
  1834     meet_left_comm          ~> inf_left_commute
  1835     meet_left_idempotent    ~> inf_left_idem
  1836     join_left_comm          ~> sup_left_commute
  1837     join_left_idempotent    ~> sup_left_idem
  1838     meet_aci                ~> inf_aci
  1839     join_aci                ~> sup_aci
  1840     le_def_meet             ~> le_iff_inf
  1841     le_def_join             ~> le_iff_sup
  1842     join_absorp2            ~> sup_absorb2
  1843     join_absorp1            ~> sup_absorb1
  1844     meet_absorp1            ~> inf_absorb1
  1845     meet_absorp2            ~> inf_absorb2
  1846     meet_join_absorp        ~> inf_sup_absorb
  1847     join_meet_absorp        ~> sup_inf_absorb
  1848     distrib_join_le         ~> distrib_sup_le
  1849     distrib_meet_le         ~> distrib_inf_le
  1850 
  1851     add_meet_distrib_left   ~> add_inf_distrib_left
  1852     add_join_distrib_left   ~> add_sup_distrib_left
  1853     is_join_neg_meet        ~> is_join_neg_inf
  1854     is_meet_neg_join        ~> is_meet_neg_sup
  1855     add_meet_distrib_right  ~> add_inf_distrib_right
  1856     add_join_distrib_right  ~> add_sup_distrib_right
  1857     add_meet_join_distribs  ~> add_sup_inf_distribs
  1858     join_eq_neg_meet        ~> sup_eq_neg_inf
  1859     meet_eq_neg_join        ~> inf_eq_neg_sup
  1860     add_eq_meet_join        ~> add_eq_inf_sup
  1861     meet_0_imp_0            ~> inf_0_imp_0
  1862     join_0_imp_0            ~> sup_0_imp_0
  1863     meet_0_eq_0             ~> inf_0_eq_0
  1864     join_0_eq_0             ~> sup_0_eq_0
  1865     neg_meet_eq_join        ~> neg_inf_eq_sup
  1866     neg_join_eq_meet        ~> neg_sup_eq_inf
  1867     join_eq_if              ~> sup_eq_if
  1868 
  1869     mono_meet               ~> mono_inf
  1870     mono_join               ~> mono_sup
  1871     meet_bool_eq            ~> inf_bool_eq
  1872     join_bool_eq            ~> sup_bool_eq
  1873     meet_fun_eq             ~> inf_fun_eq
  1874     join_fun_eq             ~> sup_fun_eq
  1875     meet_set_eq             ~> inf_set_eq
  1876     join_set_eq             ~> sup_set_eq
  1877     meet1_iff               ~> inf1_iff
  1878     meet2_iff               ~> inf2_iff
  1879     meet1I                  ~> inf1I
  1880     meet2I                  ~> inf2I
  1881     meet1D1                 ~> inf1D1
  1882     meet2D1                 ~> inf2D1
  1883     meet1D2                 ~> inf1D2
  1884     meet2D2                 ~> inf2D2
  1885     meet1E                  ~> inf1E
  1886     meet2E                  ~> inf2E
  1887     join1_iff               ~> sup1_iff
  1888     join2_iff               ~> sup2_iff
  1889     join1I1                 ~> sup1I1
  1890     join2I1                 ~> sup2I1
  1891     join1I1                 ~> sup1I1
  1892     join2I2                 ~> sup1I2
  1893     join1CI                 ~> sup1CI
  1894     join2CI                 ~> sup2CI
  1895     join1E                  ~> sup1E
  1896     join2E                  ~> sup2E
  1897 
  1898     is_meet_Meet            ~> is_meet_Inf
  1899     Meet_bool_def           ~> Inf_bool_def
  1900     Meet_fun_def            ~> Inf_fun_def
  1901     Meet_greatest           ~> Inf_greatest
  1902     Meet_lower              ~> Inf_lower
  1903     Meet_set_def            ~> Inf_set_def
  1904 
  1905     Sup_def                 ~> Sup_Inf
  1906     Sup_bool_eq             ~> Sup_bool_def
  1907     Sup_fun_eq              ~> Sup_fun_def
  1908     Sup_set_eq              ~> Sup_set_def
  1909 
  1910     listsp_meetI            ~> listsp_infI
  1911     listsp_meet_eq          ~> listsp_inf_eq
  1912 
  1913     meet_min                ~> inf_min
  1914     join_max                ~> sup_max
  1915 
  1916 * Added syntactic class "size"; overloaded constant "size" now has
  1917 type "'a::size ==> bool"
  1918 
  1919 * Internal reorganisation of `size' of datatypes: size theorems
  1920 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1921 simplification rules by default!); theorems "prod.size" now named
  1922 "*.size".
  1923 
  1924 * Class "div" now inherits from class "times" rather than "type".
  1925 INCOMPATIBILITY.
  1926 
  1927 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1928 Linorder etc.  have disappeared; operations defined in terms of
  1929 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1930 
  1931 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1932 
  1933 * HOL-Word: New extensive library and type for generic, fixed size
  1934 machine words, with arithemtic, bit-wise, shifting and rotating
  1935 operations, reflection into int, nat, and bool lists, automation for
  1936 linear arithmetic (by automatic reflection into nat or int), including
  1937 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1938 arithmetic type classes, supporting automatic simplification of
  1939 numerals on all operations.
  1940 
  1941 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1942 
  1943 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1944 
  1945 * Code generator library theories:
  1946   - Code_Integer represents HOL integers by big integer literals in target
  1947     languages.
  1948   - Code_Char represents HOL characters by character literals in target
  1949     languages.
  1950   - Code_Char_chr like Code_Char, but also offers treatment of character
  1951     codes; includes Code_Integer.
  1952   - Executable_Set allows to generate code for finite sets using lists.
  1953   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1954     denominator).
  1955   - Executable_Real implements a subset of real numbers, namly those
  1956     representable by rational numbers.
  1957   - Efficient_Nat implements natural numbers by integers, which in general will
  1958     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1959     includes Code_Integer.
  1960   - Code_Index provides an additional datatype index which is mapped to
  1961     target-language built-in integers.
  1962   - Code_Message provides an additional datatype message_string which is isomorphic to
  1963     strings; messages are mapped to target-language strings.
  1964 
  1965 * New package for inductive predicates
  1966 
  1967   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1968 
  1969     inductive
  1970       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1971       for z_1 :: U_1 and ... and z_n :: U_m
  1972     where
  1973       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1974     | ...
  1975 
  1976   with full support for type-inference, rather than
  1977 
  1978     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1979 
  1980     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1981     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1982 
  1983     inductive "s z_1 ... z_m"
  1984     intros
  1985       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1986       ...
  1987 
  1988   For backward compatibility, there is a wrapper allowing inductive
  1989   sets to be defined with the new package via
  1990 
  1991     inductive_set
  1992       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1993       for z_1 :: U_1 and ... and z_n :: U_m
  1994     where
  1995       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1996     | ...
  1997 
  1998   or
  1999 
  2000     inductive_set
  2001       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2002       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2003       for z_1 :: U_1 and ... and z_n :: U_m
  2004     where
  2005       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2006     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2007     | ...
  2008 
  2009   if the additional syntax "p ..." is required.
  2010 
  2011   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2012   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2013 
  2014   INCOMPATIBILITIES:
  2015 
  2016   - Since declaration and definition of inductive sets or predicates
  2017     is no longer separated, abbreviations involving the newly
  2018     introduced sets or predicates must be specified together with the
  2019     introduction rules after the 'where' keyword (see above), rather
  2020     than before the actual inductive definition.
  2021 
  2022   - The variables in induction and elimination rules are now
  2023     quantified in the order of their occurrence in the introduction
  2024     rules, rather than in alphabetical order. Since this may break
  2025     some proofs, these proofs either have to be repaired, e.g. by
  2026     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2027     statements of the form
  2028 
  2029       case (rule_i a_i_1 ... a_i_{k_i})
  2030 
  2031     or the old order of quantification has to be restored by explicitly adding
  2032     meta-level quantifiers in the introduction rules, i.e.
  2033 
  2034       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2035 
  2036   - The format of the elimination rules is now
  2037 
  2038       p z_1 ... z_m x_1 ... x_n ==>
  2039         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2040         ==> ... ==> P
  2041 
  2042     for predicates and
  2043 
  2044       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2045         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2046         ==> ... ==> P
  2047 
  2048     for sets rather than
  2049 
  2050       x : s z_1 ... z_m ==>
  2051         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2052         ==> ... ==> P
  2053 
  2054     This may require terms in goals to be expanded to n-tuples
  2055     (e.g. using case_tac or simplification with the split_paired_all
  2056     rule) before the above elimination rule is applicable.
  2057 
  2058   - The elimination or case analysis rules for (mutually) inductive
  2059     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2060     list of rules "p_1_..._p_k.elims" is no longer available.
  2061 
  2062 * New package "function"/"fun" for general recursive functions,
  2063 supporting mutual and nested recursion, definitions in local contexts,
  2064 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2065 for small examples, and the separate tutorial on the function
  2066 package. The old recdef "package" is still available as before, but
  2067 users are encouraged to use the new package.
  2068 
  2069 * Method "lexicographic_order" automatically synthesizes termination
  2070 relations as lexicographic combinations of size measures. 
  2071 
  2072 * Case-expressions allow arbitrary constructor-patterns (including
  2073 "_") and take their order into account, like in functional
  2074 programming.  Internally, this is translated into nested
  2075 case-expressions; missing cases are added and mapped to the predefined
  2076 constant "undefined". In complicated cases printing may no longer show
  2077 the original input but the internal form. Lambda-abstractions allow
  2078 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2079 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2080 variable.
  2081 
  2082 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2083 is an abbreviation for "of_nat :: nat => int". The simplification
  2084 rules for "of_nat" have been changed to work like "int" did
  2085 previously.  Potential INCOMPATIBILITY:
  2086   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2087   - of_nat_diff and of_nat_mult are no longer default simp rules
  2088 
  2089 * Method "algebra" solves polynomial equations over (semi)rings using
  2090 Groebner bases. The (semi)ring structure is defined by locales and the
  2091 tool setup depends on that generic context. Installing the method for
  2092 a specific type involves instantiating the locale and possibly adding
  2093 declarations for computation on the coefficients.  The method is
  2094 already instantiated for natural numbers and for the axiomatic class
  2095 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2096 CALCULEMUS 2007 for the general principles underlying this
  2097 architecture of context-aware proof-tools.
  2098 
  2099 * Method "ferrack" implements quantifier elimination over
  2100 special-purpose dense linear orders using locales (analogous to
  2101 "algebra"). The method is already installed for class
  2102 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2103 rat, etc.
  2104 
  2105 * Former constant "List.op @" now named "List.append".  Use ML
  2106 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2107 circumvent possible incompatibilities when working on ML level.
  2108 
  2109 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2110 
  2111 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2112 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2113 
  2114 * New syntax for Haskell-like list comprehension (input only), eg.
  2115 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2116 
  2117 * The special syntax for function "filter" has changed from [x :
  2118 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2119 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2120 
  2121 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2122 defined on nat only, as an abbreviation for [a..<Suc b]
  2123 INCOMPATIBILITY.
  2124 
  2125 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2126 
  2127 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2128 
  2129 * New lemma collection field_simps (an extension of ring_simps) for
  2130 manipulating (in)equations involving division. Multiplies with all
  2131 denominators that can be proved to be non-zero (in equations) or
  2132 positive/negative (in inequations).
  2133 
  2134 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2135 have been improved and renamed to ring_simps, group_simps and
  2136 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2137 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2138 
  2139 * Theory Library/Commutative_Ring: switched from recdef to function
  2140 package; constants add, mul, pow now curried.  Infix syntax for
  2141 algebraic operations.
  2142 
  2143 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2144 INCOMPATIBILITY.
  2145 
  2146 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2147 INCOMPATIBILITY.
  2148 
  2149 * HOL/records: generalised field-update to take a function on the
  2150 field rather than the new value: r(|A := x|) is translated to A_update
  2151 (K x) r The K-combinator that is internally used is called K_record.
  2152 INCOMPATIBILITY: Usage of the plain update functions has to be
  2153 adapted.
  2154  
  2155 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2156 * x = 0, which are required for a semiring.  Richer structures do not
  2157 inherit from semiring_0 anymore, because this property is a theorem
  2158 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2159 there is more to prove, but this is mostly trivial.
  2160 
  2161 * Class "recpower" is generalized to arbitrary monoids, not just
  2162 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2163 commutativity or semiring properties additionally.
  2164 
  2165 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2166 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2167 better use 'abbreviation'.
  2168 
  2169 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2170 
  2171 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2172 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2173 significant changes for setting up numeral syntax for types:
  2174   - New constants Numeral.pred and Numeral.succ instead
  2175       of former Numeral.bin_pred and Numeral.bin_succ.
  2176   - Use integer operations instead of bin_add, bin_mult and so on.
  2177   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2178   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2179 
  2180 See src/HOL/Integ/IntArith.thy for an example setup.
  2181 
  2182 * Command 'normal_form' computes the normal form of a term that may
  2183 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2184 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2185 heavy-duty computations because the functions are compiled to ML
  2186 first.  Correspondingly, a method "normalization" is provided.  See
  2187 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2188 
  2189 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2190 25 like -->); output depends on the "iff" print_mode, the default is
  2191 "A = B" (with priority 50).
  2192 
  2193 * Relations less (<) and less_eq (<=) are also available on type bool.
  2194 Modified syntax to disallow nesting without explicit parentheses,
  2195 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2196 INCOMPATIBILITY.
  2197 
  2198 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2199 
  2200 * Relation composition operator "op O" now has precedence 75 and binds
  2201 stronger than union and intersection. INCOMPATIBILITY.
  2202 
  2203 * The old set interval syntax "{m..n(}" (and relatives) has been
  2204 removed.  Use "{m..<n}" (and relatives) instead.
  2205 
  2206 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2207 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2208 ``declare [[simproc del: neq]]''.
  2209 
  2210 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2211 True/False.
  2212 
  2213 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2214 
  2215 * Theorem setsum_mult renamed to setsum_right_distrib.
  2216 
  2217 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2218 ``rule'' method.
  2219 
  2220 * Reimplemented methods "sat" and "satx", with several improvements:
  2221 goals no longer need to be stated as "<prems> ==> False", equivalences
  2222 (i.e. "=" on type bool) are handled, variable names of the form
  2223 "lit_<n>" are no longer reserved, significant speedup.
  2224 
  2225 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2226 zChaff is still supported as well.
  2227 
  2228 * 'inductive' and 'datatype': provide projections of mutual rules,
  2229 bundled as foo_bar.inducts;
  2230 
  2231 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2232 Library.
  2233 
  2234 * Library: moved theory Accessible_Part to main HOL.
  2235 
  2236 * Library: added theory Coinductive_List of potentially infinite lists
  2237 as greatest fixed-point.
  2238 
  2239 * Library: added theory AssocList which implements (finite) maps as
  2240 association lists.
  2241 
  2242 * Method "evaluation" solves goals (i.e. a boolean expression)
  2243 efficiently by compiling it to ML.  The goal is "proved" (via an
  2244 oracle) if it evaluates to True.
  2245 
  2246 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2247 also when invoked by the simplifier.  This results in the Simplifier
  2248 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2249 Configuration option fast_arith_split_limit=0 recovers the old
  2250 behavior.
  2251 
  2252 * Support for hex (0x20) and binary (0b1001) numerals.
  2253 
  2254 * New method: reify eqs (t), where eqs are equations for an
  2255 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2256 parameter, computes a term s::'b and a list xs::'a list and proves the
  2257 theorem I xs s = t. This is also known as reification or quoting. The
  2258 resulting theorem is applied to the subgoal to substitute t with I xs
  2259 s.  If t is omitted, the subgoal itself is reified.
  2260 
  2261 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2262 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2263 where f is supposed to be a computable function (in the sense of code
  2264 generattion). The method uses reify to compute s and xs as above then
  2265 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2266 r and finally gets the theorem t = r, which is again applied to the
  2267 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2268 
  2269 * Reflection: Automatic reification now handels binding, an example is
  2270 available in src/HOL/ex/ReflectionEx.thy
  2271 
  2272 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2273 command 'statespace' that is similar to 'record', but introduces an
  2274 abstract specification based on the locale infrastructure instead of
  2275 HOL types.  This leads to extra flexibility in composing state spaces,
  2276 in particular multiple inheritance and renaming of components.
  2277 
  2278 
  2279 *** HOL-Complex ***
  2280 
  2281 * Hyperreal: Functions root and sqrt are now defined on negative real
  2282 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2283 Nonnegativity side conditions have been removed from many lemmas, so
  2284 that more subgoals may now be solved by simplification; potential
  2285 INCOMPATIBILITY.
  2286 
  2287 * Real: new type classes formalize real normed vector spaces and
  2288 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2289 and norm :: 'a => real.
  2290 
  2291 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2292 reals into other types. The overloaded constant Reals :: 'a set is now
  2293 defined as range of_real; potential INCOMPATIBILITY.
  2294 
  2295 * Real: proper support for ML code generation, including 'quickcheck'.
  2296 Reals are implemented as arbitrary precision rationals.
  2297 
  2298 * Hyperreal: Several constants that previously worked only for the
  2299 reals have been generalized, so they now work over arbitrary vector
  2300 spaces. Type annotations may need to be added in some cases; potential
  2301 INCOMPATIBILITY.
  2302 
  2303   Infinitesimal  :: ('a::real_normed_vector) star set
  2304   HFinite        :: ('a::real_normed_vector) star set
  2305   HInfinite      :: ('a::real_normed_vector) star set
  2306   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2307   monad          :: ('a::real_normed_vector) star => 'a star set
  2308   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2309   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2310   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2311   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2312   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2313   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2314   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2315   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2316   sgn            :: 'a::real_normed_vector => 'a
  2317   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2318 
  2319 * Complex: Some complex-specific constants are now abbreviations for
  2320 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2321 hnorm.  Other constants have been entirely removed in favor of the
  2322 polymorphic versions (INCOMPATIBILITY):
  2323 
  2324   approx        <-- capprox
  2325   HFinite       <-- CFinite
  2326   HInfinite     <-- CInfinite
  2327   Infinitesimal <-- CInfinitesimal
  2328   monad         <-- cmonad
  2329   galaxy        <-- cgalaxy
  2330   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2331   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2332   (ns)deriv     <-- (ns)cderiv
  2333 
  2334 
  2335 *** HOL-Algebra ***
  2336 
  2337 * Formalisation of ideals and the quotient construction over rings.
  2338 
  2339 * Order and lattice theory no longer based on records.
  2340 INCOMPATIBILITY.
  2341 
  2342 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2343 greatest_closed.  INCOMPATIBILITY.
  2344 
  2345 * Method algebra is now set up via an attribute.  For examples see
  2346 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2347 of algebraic structures.
  2348 
  2349 * Renamed theory CRing to Ring.
  2350 
  2351 
  2352 *** HOL-Nominal ***
  2353 
  2354 * Substantial, yet incomplete support for nominal datatypes (binding
  2355 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2356 src/HOL/Nominal/Examples.  Prospective users should consult
  2357 http://isabelle.in.tum.de/nominal/
  2358 
  2359 
  2360 *** ML ***
  2361 
  2362 * ML basics: just one true type int, which coincides with IntInf.int
  2363 (even on SML/NJ).
  2364 
  2365 * ML within Isar: antiquotations allow to embed statically-checked
  2366 formal entities in the source, referring to the context available at
  2367 compile-time.  For example:
  2368 
  2369 ML {* @{sort "{zero,one}"} *}
  2370 ML {* @{typ "'a => 'b"} *}
  2371 ML {* @{term "%x. x"} *}
  2372 ML {* @{prop "x == y"} *}
  2373 ML {* @{ctyp "'a => 'b"} *}
  2374 ML {* @{cterm "%x. x"} *}
  2375 ML {* @{cprop "x == y"} *}
  2376 ML {* @{thm asm_rl} *}
  2377 ML {* @{thms asm_rl} *}
  2378 ML {* @{type_name c} *}
  2379 ML {* @{type_syntax c} *}
  2380 ML {* @{const_name c} *}
  2381 ML {* @{const_syntax c} *}
  2382 ML {* @{context} *}
  2383 ML {* @{theory} *}
  2384 ML {* @{theory Pure} *}
  2385 ML {* @{theory_ref} *}
  2386 ML {* @{theory_ref Pure} *}
  2387 ML {* @{simpset} *}
  2388 ML {* @{claset} *}
  2389 ML {* @{clasimpset} *}
  2390 
  2391 The same works for sources being ``used'' within an Isar context.
  2392 
  2393 * ML in Isar: improved error reporting; extra verbosity with
  2394 ML_Context.trace enabled.
  2395 
  2396 * Pure/General/table.ML: the join operations now works via exceptions
  2397 DUP/SAME instead of type option. This is simpler in simple cases, and
  2398 admits slightly more efficient complex applications.
  2399 
  2400 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2401 use Context.generic instead of just theory.
  2402 
  2403 * Pure: datatype Context.generic joins theory/Proof.context and
  2404 provides some facilities for code that works in either kind of
  2405 context, notably GenericDataFun for uniform theory and proof data.
  2406 
  2407 * Pure: simplified internal attribute type, which is now always
  2408 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2409 local (Proof.context) attributes have been discontinued, while
  2410 minimizing code duplication. Thm.rule_attribute and
  2411 Thm.declaration_attribute build canonical attributes; see also structure
  2412 Context for further operations on Context.generic, notably
  2413 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2414 declarations and definitions.
  2415 
  2416 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2417 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2418 init only required for impure data. INCOMPATIBILITY: empty really need
  2419 to be empty (no dependencies on theory content!)
  2420 
  2421 * Pure/kernel: consts certification ignores sort constraints given in
  2422 signature declarations. (This information is not relevant to the
  2423 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2424 potential INCOMPATIBILITY.
  2425 
  2426 * Pure: axiomatic type classes are now purely definitional, with
  2427 explicit proofs of class axioms and super class relations performed
  2428 internally. See Pure/axclass.ML for the main internal interfaces --
  2429 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2430 AxClass.axiomatize_class/classrel/arity supersede
  2431 Sign.add_classes/classrel/arities.
  2432 
  2433 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2434 global/local versions on theory vs. Proof.context have been
  2435 discontinued; Attrib.syntax and Method.syntax have been adapted
  2436 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2437 attributes, methods, etc.
  2438 
  2439 * Pure: several functions of signature "... -> theory -> theory * ..."
  2440 have been reoriented to "... -> theory -> ... * theory" in order to
  2441 allow natural usage in combination with the ||>, ||>>, |-> and
  2442 fold_map combinators.
  2443 
  2444 * Pure: official theorem names (closed derivations) and additional
  2445 comments (tags) are now strictly separate.  Name hints -- which are
  2446 maintained as tags -- may be attached any time without affecting the
  2447 derivation.
  2448 
  2449 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2450 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2451 achieve the old behaviour.
  2452 
  2453 * Pure: the "Goal" constant is now called "prop", supporting a
  2454 slightly more general idea of ``protecting'' meta-level rule
  2455 statements.
  2456 
  2457 * Pure: Logic.(un)varify only works in a global context, which is now
  2458 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2459 Logic.legacy_(un)varify as temporary workaround.
  2460 
  2461 * Pure: structure Name provides scalable operations for generating
  2462 internal variable names, notably Name.variants etc.  This replaces
  2463 some popular functions from term.ML:
  2464 
  2465   Term.variant		->  Name.variant
  2466   Term.variantlist	->  Name.variant_list
  2467   Term.invent_names	->  Name.invent_list
  2468 
  2469 Note that low-level renaming rarely occurs in new code -- operations
  2470 from structure Variable are used instead (see below).
  2471 
  2472 * Pure: structure Variable provides fundamental operations for proper
  2473 treatment of fixed/schematic variables in a context.  For example,
  2474 Variable.import introduces fixes for schematics of given facts and
  2475 Variable.export reverses the effect (up to renaming) -- this replaces
  2476 various freeze_thaw operations.
  2477 
  2478 * Pure: structure Goal provides simple interfaces for
  2479 init/conclude/finish and tactical prove operations (replacing former
  2480 Tactic.prove).  Goal.prove is the canonical way to prove results
  2481 within a given context; Goal.prove_global is a degraded version for
  2482 theory level goals, including a global Drule.standard.  Note that
  2483 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2484 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2485 in a locale context).
  2486 
  2487 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2488 and type checking (Syntax.check_term etc.), with common combinations
  2489 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2490 which are considered legacy and await removal.
  2491 
  2492 * Pure/Syntax: generic interfaces for type unchecking
  2493 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2494 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2495 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2496 available for convenience, but refer to the very same operations using
  2497 a mere theory instead of a full context.
  2498 
  2499 * Isar: simplified treatment of user-level errors, using exception
  2500 ERROR of string uniformly.  Function error now merely raises ERROR,
  2501 without any side effect on output channels.  The Isar toplevel takes
  2502 care of proper display of ERROR exceptions.  ML code may use plain
  2503 handle/can/try; cat_error may be used to concatenate errors like this:
  2504 
  2505   ... handle ERROR msg => cat_error msg "..."
  2506 
  2507 Toplevel ML code (run directly or through the Isar toplevel) may be
  2508 embedded into the Isar toplevel with exception display/debug like
  2509 this:
  2510 
  2511   Isar.toplevel (fn () => ...)
  2512 
  2513 INCOMPATIBILITY, removed special transform_error facilities, removed
  2514 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2515 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2516 -- use plain ERROR instead.
  2517 
  2518 * Isar: theory setup now has type (theory -> theory), instead of a
  2519 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2520 
  2521 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2522 ProofContext.debug/verbose flags.
  2523 
  2524 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2525 theory before entering a proof state.  Transactions now always see a
  2526 quasi-functional intermediate checkpoint, both in interactive and
  2527 batch mode.
  2528 
  2529 * Isar: simplified interfaces for outer syntax.  Renamed
  2530 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2531 OuterSyntax.add_parsers -- this functionality is now included in
  2532 OuterSyntax.command etc.  INCOMPATIBILITY.
  2533 
  2534 * Simplifier: the simpset of a running simplification process now
  2535 contains a proof context (cf. Simplifier.the_context), which is the
  2536 very context that the initial simpset has been retrieved from (by
  2537 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2538 (solver, looper etc.) may depend on arbitrary proof data.
  2539 
  2540 * Simplifier.inherit_context inherits the proof context (plus the
  2541 local bounds) of the current simplification process; any simproc
  2542 etc. that calls the Simplifier recursively should do this!  Removed
  2543 former Simplifier.inherit_bounds, which is already included here --
  2544 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2545 specify an explicit context using Simplifier.context/theory_context.
  2546 
  2547 * Simplifier/Classical Reasoner: more abstract interfaces
  2548 change_simpset/claset for modifying the simpset/claset reference of a
  2549 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2550 INCOMPATIBILITY.
  2551 
  2552 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2553 "Trueprop" etc.
  2554 
  2555 
  2556 *** System ***
  2557 
  2558 * settings: the default heap location within ISABELLE_HOME_USER now
  2559 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2560 Isabelle installations.
  2561 
  2562 * isabelle-process: option -S (secure mode) disables some critical
  2563 operations, notably runtime compilation and evaluation of ML source
  2564 code.
  2565 
  2566 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2567 
  2568 * Support for parallel execution, using native multicore support of
  2569 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2570 independent theories, according to the given theory header
  2571 specifications. The maximum number of worker threads is specified via
  2572 usedir option -M or the "max-threads" setting in Proof General. A
  2573 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2574 to 6 on a 8-core machine.  User-code needs to observe certain
  2575 guidelines for thread-safe programming, see appendix A in the Isar
  2576 Implementation manual.
  2577 
  2578 
  2579 
  2580 New in Isabelle2005 (October 2005)
  2581 ----------------------------------
  2582 
  2583 *** General ***
  2584 
  2585 * Theory headers: the new header syntax for Isar theories is
  2586 
  2587   theory <name>
  2588   imports <theory1> ... <theoryN>
  2589   uses <file1> ... <fileM>
  2590   begin
  2591 
  2592 where the 'uses' part is optional.  The previous syntax
  2593 
  2594   theory <name> = <theory1> + ... + <theoryN>:
  2595 
  2596 will disappear in the next release.  Use isatool fixheaders to convert
  2597 existing theory files.  Note that there is no change in ancient
  2598 non-Isar theories now, but these will disappear soon.
  2599 
  2600 * Theory loader: parent theories can now also be referred to via
  2601 relative and absolute paths.
  2602 
  2603 * Command 'find_theorems' searches for a list of criteria instead of a
  2604 list of constants. Known criteria are: intro, elim, dest, name:string,
  2605 simp:term, and any term. Criteria can be preceded by '-' to select
  2606 theorems that do not match. Intro, elim, dest select theorems that
  2607 match the current goal, name:s selects theorems whose fully qualified
  2608 name contain s, and simp:term selects all simplification rules whose
  2609 lhs match term.  Any other term is interpreted as pattern and selects
  2610 all theorems matching the pattern. Available in ProofGeneral under
  2611 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2612 
  2613   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2614 
  2615 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2616 matching the current goal as introduction rule and not having "HOL."
  2617 in their name (i.e. not being defined in theory HOL).
  2618 
  2619 * Command 'thms_containing' has been discontinued in favour of
  2620 'find_theorems'; INCOMPATIBILITY.
  2621 
  2622 * Communication with Proof General is now 8bit clean, which means that
  2623 Unicode text in UTF-8 encoding may be used within theory texts (both
  2624 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2625 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2626 
  2627   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2628   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2629 
  2630 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2631 Classical Reasoner.  Typical big applications run around 2 times
  2632 faster.
  2633 
  2634 
  2635 *** Document preparation ***
  2636 
  2637 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2638 of raw sources.  Only those symbols that do not require additional
  2639 LaTeX packages (depending on comments in isabellesym.sty) are
  2640 displayed properly, everything else is left verbatim.  isatool display
  2641 and isatool print are used as front ends (these are subject to the
  2642 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2643 
  2644 * Command tags control specific markup of certain regions of text,
  2645 notably folding and hiding.  Predefined tags include "theory" (for
  2646 theory begin and end), "proof" for proof commands, and "ML" for
  2647 commands involving ML code; the additional tags "visible" and
  2648 "invisible" are unused by default.  Users may give explicit tag
  2649 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2650 interpretation of tags is determined by the LaTeX job during document
  2651 preparation: see option -V of isatool usedir, or options -n and -t of
  2652 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2653 \isadroptag.
  2654 
  2655 Several document versions may be produced at the same time via isatool
  2656 usedir (the generated index.html will link all of them).  Typical
  2657 specifications include ''-V document=theory,proof,ML'' to present
  2658 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2659 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2660 these parts without any formal replacement text.  The Isabelle site
  2661 default settings produce ''document'' and ''outline'' versions as
  2662 specified above.
  2663 
  2664 * Several new antiquotations:
  2665 
  2666   @{term_type term} prints a term with its type annotated;
  2667 
  2668   @{typeof term} prints the type of a term;
  2669 
  2670   @{const const} is the same as @{term const}, but checks that the
  2671   argument is a known logical constant;
  2672 
  2673   @{term_style style term} and @{thm_style style thm} print a term or
  2674   theorem applying a "style" to it
  2675 
  2676   @{ML text}
  2677 
  2678 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2679 definitions, equations, inequations etc., 'concl' printing only the
  2680 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2681 to print the specified premise.  TermStyle.add_style provides an ML
  2682 interface for introducing further styles.  See also the "LaTeX Sugar"
  2683 document practical applications.  The ML antiquotation prints
  2684 type-checked ML expressions verbatim.
  2685 
  2686 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2687 and 'text' support optional locale specification '(in loc)', which
  2688 specifies the default context for interpreting antiquotations.  For
  2689 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2690 
  2691 * Option 'locale=NAME' of antiquotations specifies an alternative
  2692 context interpreting the subsequent argument.  For example: @{thm
  2693 [locale=lattice] inf_assoc}.
  2694 
  2695 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2696 a proof context.
  2697 
  2698 * Proper output of antiquotations for theory commands involving a
  2699 proof context (such as 'locale' or 'theorem (in loc) ...').
  2700 
  2701 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2702 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2703 
  2704 * isatool usedir: new option -C (default true) controls whether option
  2705 -D should include a copy of the original document directory; -C false
  2706 prevents unwanted effects such as copying of administrative CVS data.
  2707 
  2708 
  2709 *** Pure ***
  2710 
  2711 * Considerably improved version of 'constdefs' command.  Now performs
  2712 automatic type-inference of declared constants; additional support for
  2713 local structure declarations (cf. locales and HOL records), see also
  2714 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2715 sequential dependencies of definitions within a single 'constdefs'
  2716 section; moreover, the declared name needs to be an identifier.  If
  2717 all fails, consider to fall back on 'consts' and 'defs' separately.
  2718 
  2719 * Improved indexed syntax and implicit structures.  First of all,
  2720 indexed syntax provides a notational device for subscripted
  2721 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2722 expressions.  Secondly, in a local context with structure
  2723 declarations, number indexes \<^sub>n or the empty index (default
  2724 number 1) refer to a certain fixed variable implicitly; option
  2725 show_structs controls printing of implicit structures.  Typical
  2726 applications of these concepts involve record types and locales.
  2727 
  2728 * New command 'no_syntax' removes grammar declarations (and
  2729 translations) resulting from the given syntax specification, which is
  2730 interpreted in the same manner as for the 'syntax' command.
  2731 
  2732 * 'Advanced' translation functions (parse_translation etc.) may depend
  2733 on the signature of the theory context being presently used for
  2734 parsing/printing, see also isar-ref manual.
  2735 
  2736 * Improved 'oracle' command provides a type-safe interface to turn an
  2737 ML expression of type theory -> T -> term into a primitive rule of
  2738 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2739 is already included here); see also FOL/ex/IffExample.thy;
  2740 INCOMPATIBILITY.
  2741 
  2742 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2743 before); "cI" is no longer bound, use "c.intro" instead.
  2744 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2745 axclasses vs. locales.
  2746 
  2747 * Improved internal renaming of symbolic identifiers -- attach primes
  2748 instead of base 26 numbers.
  2749 
  2750 * New flag show_question_marks controls printing of leading question
  2751 marks in schematic variable names.
  2752 
  2753 * In schematic variable names, *any* symbol following \<^isub> or
  2754 \<^isup> is now treated as part of the base name.  For example, the
  2755 following works without printing of awkward ".0" indexes:
  2756 
  2757   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2758     by simp
  2759 
  2760 * Inner syntax includes (*(*nested*) comments*).
  2761 
  2762 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2763 annotations as "(00...)".
  2764 
  2765 * Clear separation of logical types and nonterminals, where the latter
  2766 may only occur in 'syntax' specifications or type abbreviations.
  2767 Before that distinction was only partially implemented via type class
  2768 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2769 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2770 exotic syntax specifications may require further adaption
  2771 (e.g. Cube/Cube.thy).
  2772 
  2773 * Removed obsolete type class "logic", use the top sort {} instead.
  2774 Note that non-logical types should be declared as 'nonterminals'
  2775 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2776 specifications.
  2777 
  2778 * Attributes 'induct' and 'cases': type or set names may now be
  2779 locally fixed variables as well.
  2780 
  2781 * Simplifier: can now control the depth to which conditional rewriting
  2782 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2783 Limit.
  2784 
  2785 * Simplifier: simplification procedures may now take the current
  2786 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2787 interface), which is very useful for calling the Simplifier
  2788 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2789 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2790 low-level mk_simproc no longer applies Logic.varify internally, to
  2791 allow for use in a context of fixed variables.
  2792 
  2793 * thin_tac now works even if the assumption being deleted contains !!
  2794 or ==>.  More generally, erule now works even if the major premise of
  2795 the elimination rule contains !! or ==>.
  2796 
  2797 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2798 
  2799 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2800 from Pure, which contains all common declarations already.  Both
  2801 theories are defined via plain Isabelle/Isar .thy files.
  2802 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2803 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2804 use isatool fixcpure to adapt your theory and ML sources.
  2805 
  2806 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2807 selections of theorems in named facts via index ranges.
  2808 
  2809 * 'print_theorems': in theory mode, really print the difference
  2810 wrt. the last state (works for interactive theory development only),
  2811 in proof mode print all local facts (cf. 'print_facts');
  2812 
  2813 * 'hide': option '(open)' hides only base names.
  2814 
  2815 * More efficient treatment of intermediate checkpoints in interactive
  2816 theory development.
  2817 
  2818 * Code generator is now invoked via code_module (incremental code
  2819 generation) and code_library (modular code generation, ML structures
  2820 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2821 must be quoted when used as identifiers.
  2822 
  2823 * New 'value' command for reading, evaluating and printing terms using
  2824 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2825 quoted when used as identifier.
  2826 
  2827 
  2828 *** Locales ***
  2829 
  2830 * New commands for the interpretation of locale expressions in
  2831 theories (1), locales (2) and proof contexts (3).  These generate
  2832 proof obligations from the expression specification.  After the
  2833 obligations have been discharged, theorems of the expression are added
  2834 to the theory, target locale or proof context.  The synopsis of the
  2835 commands is a follows:
  2836 
  2837   (1) interpretation expr inst
  2838   (2) interpretation target < expr
  2839   (3) interpret expr inst
  2840 
  2841 Interpretation in theories and proof contexts require a parameter
  2842 instantiation of terms from the current context.  This is applied to
  2843 specifications and theorems of the interpreted expression.
  2844 Interpretation in locales only permits parameter renaming through the
  2845 locale expression.  Interpretation is smart in that interpretations
  2846 that are active already do not occur in proof obligations, neither are
  2847 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2848 inspect active interpretations of a particular locale.  For details,
  2849 see the Isar Reference manual.  Examples can be found in
  2850 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2851 
  2852 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2853 'interpret' instead.
  2854 
  2855 * New context element 'constrains' for adding type constraints to
  2856 parameters.
  2857 
  2858 * Context expressions: renaming of parameters with syntax
  2859 redeclaration.
  2860 
  2861 * Locale declaration: 'includes' disallowed.
  2862 
  2863 * Proper static binding of attribute syntax -- i.e. types / terms /
  2864 facts mentioned as arguments are always those of the locale definition
  2865 context, independently of the context of later invocations.  Moreover,
  2866 locale operations (renaming and type / term instantiation) are applied
  2867 to attribute arguments as expected.
  2868 
  2869 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2870 actual attributes; rare situations may require Attrib.attribute to
  2871 embed those attributes into Attrib.src that lack concrete syntax.
  2872 Attribute implementations need to cooperate properly with the static
  2873 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2874 Attrib.XXX_thm etc. already do the right thing without further
  2875 intervention.  Only unusual applications -- such as "where" or "of"
  2876 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2877 on the context and the facts involved -- may have to assign parsed
  2878 values to argument tokens explicitly.
  2879 
  2880 * Changed parameter management in theorem generation for long goal
  2881 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2882 theorem statement in rare situations.
  2883 
  2884 * Locale inspection command 'print_locale' omits notes elements.  Use
  2885 'print_locale!' to have them included in the output.
  2886 
  2887 
  2888 *** Provers ***
  2889 
  2890 * Provers/hypsubst.ML: improved version of the subst method, for
  2891 single-step rewriting: it now works in bound variable contexts. New is
  2892 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2893 rewrite a different subterm than the original subst method, which is
  2894 still available as 'simplesubst'.
  2895 
  2896 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2897 and quasi orders.
  2898 
  2899 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2900 reflexive-transitive closure of relations.
  2901 
  2902 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2903 limit (previously hard-coded with a value of 20) user-definable.
  2904 
  2905 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2906 is peformed already.  Object-logics merely need to finish their
  2907 initial simpset configuration as before.  INCOMPATIBILITY.
  2908 
  2909 
  2910 *** HOL ***
  2911 
  2912 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2913 
  2914   syntax (epsilon)
  2915     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2916 
  2917 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2918 and x-symbol; use option '-m epsilon' to get it actually printed.
  2919 Moreover, the mathematically important symbolic identifier \<epsilon>
  2920 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2921 
  2922 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2923 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2924 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2925 support corresponding Isar calculations.
  2926 
  2927 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2928 instead of ":".
  2929 
  2930 * theory SetInterval: changed the syntax for open intervals:
  2931 
  2932   Old       New
  2933   {..n(}    {..<n}
  2934   {)n..}    {n<..}
  2935   {m..n(}   {m..<n}
  2936   {)m..n}   {m<..n}
  2937   {)m..n(}  {m<..<n}
  2938 
  2939 The old syntax is still supported but will disappear in the next
  2940 release.  For conversion use the following Emacs search and replace
  2941 patterns (these are not perfect but work quite well):
  2942 
  2943   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2944   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2945 
  2946 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2947 equalities in commutative rings; method 'algebra' provides a generic
  2948 interface.
  2949 
  2950 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2951 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2952 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2953 be a tuple pattern.
  2954 
  2955 Some new syntax forms are available:
  2956 
  2957   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2958   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2959   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2960   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2961 
  2962 The latter form "\<Sum>x < k. e" used to be based on a separate
  2963 function "Summation", which has been discontinued.
  2964 
  2965 * theory Finite_Set: in structured induction proofs, the insert case
  2966 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2967 (insert F x)'.
  2968 
  2969 * The 'refute' command has been extended to support a much larger
  2970 fragment of HOL, including axiomatic type classes, constdefs and
  2971 typedefs, inductive datatypes and recursion.
  2972 
  2973 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2974 Requires zChaff with proof generation to be installed.  See
  2975 HOL/ex/SAT_Examples.thy for examples.
  2976 
  2977 * Datatype induction via method 'induct' now preserves the name of the
  2978 induction variable. For example, when proving P(xs::'a list) by
  2979 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2980 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2981 in unstructured proof scripts.
  2982 
  2983 * Reworked implementation of records.  Improved scalability for
  2984 records with many fields, avoiding performance problems for type
  2985 inference. Records are no longer composed of nested field types, but
  2986 of nested extension types. Therefore the record type only grows linear
  2987 in the number of extensions and not in the number of fields.  The
  2988 top-level (users) view on records is preserved.  Potential
  2989 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2990 old record representation. The type generated for a record is called
  2991 <record_name>_ext_type.
  2992 
  2993 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2994 proofs triggered by a record definition or a simproc (if
  2995 quick_and_dirty is enabled).  Definitions of large records can take
  2996 quite long.
  2997 
  2998 New simproc record_upd_simproc for simplification of multiple record
  2999 updates enabled by default.  Moreover, trivial updates are also
  3000 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3001 occasionally, since simplification is more powerful by default.
  3002 
  3003 * typedef: proper support for polymorphic sets, which contain extra
  3004 type-variables in the term.
  3005 
  3006 * Simplifier: automatically reasons about transitivity chains
  3007 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3008 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3009 old proofs break occasionally as simplification may now solve more
  3010 goals than previously.
  3011 
  3012 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3013 present.  Works for all partial orders (class "order"), in particular
  3014 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3015 just like y <= x.
  3016 
  3017 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3018 bound variable or a constant then the let is unfolded.  Otherwise
  3019 first a is simplified to b, and then f b is simplified to g. If
  3020 possible we abstract b from g arriving at "let x = b in h x",
  3021 otherwise we unfold the let and arrive at g.  The simproc can be
  3022 enabled/disabled by the reference use_let_simproc.  Potential
  3023 INCOMPATIBILITY since simplification is more powerful by default.
  3024 
  3025 * Classical reasoning: the meson method now accepts theorems as arguments.
  3026 
  3027 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3028 jobs to provide advice on the provability of subgoals.
  3029 
  3030 * Theory OrderedGroup and Ring_and_Field: various additions and
  3031 improvements to faciliate calculations involving equalities and
  3032 inequalities.
  3033 
  3034 The following theorems have been eliminated or modified
  3035 (INCOMPATIBILITY):
  3036 
  3037   abs_eq             now named abs_of_nonneg
  3038   abs_of_ge_0        now named abs_of_nonneg
  3039   abs_minus_eq       now named abs_of_nonpos
  3040   imp_abs_id         now named abs_of_nonneg
  3041   imp_abs_neg_id     now named abs_of_nonpos
  3042   mult_pos           now named mult_pos_pos
  3043   mult_pos_le        now named mult_nonneg_nonneg
  3044   mult_pos_neg_le    now named mult_nonneg_nonpos
  3045   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3046   mult_neg           now named mult_neg_neg
  3047   mult_neg_le        now named mult_nonpos_nonpos
  3048 
  3049 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3050      
  3051      zero_le_square
  3052      not_square_less_zero 
  3053 
  3054   The following lemmas have been deleted from Real/RealPow:
  3055   
  3056      realpow_zero_zero
  3057      realpow_two
  3058      realpow_less
  3059      zero_le_power
  3060      realpow_two_le
  3061      abs_realpow_two
  3062      realpow_two_abs     
  3063 
  3064 * Theory Parity: added rules for simplifying exponents.
  3065 
  3066 * Theory List:
  3067 
  3068 The following theorems have been eliminated or modified
  3069 (INCOMPATIBILITY):
  3070 
  3071   list_all_Nil       now named list_all.simps(1)
  3072   list_all_Cons      now named list_all.simps(2)
  3073   list_all_conv      now named list_all_iff
  3074   set_mem_eq         now named mem_iff
  3075 
  3076 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3077 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3078 
  3079 
  3080 *** HOL-Complex ***
  3081 
  3082 * Theory RealDef: better support for embedding natural numbers and
  3083 integers in the reals.
  3084 
  3085 The following theorems have been eliminated or modified
  3086 (INCOMPATIBILITY):
  3087 
  3088   exp_ge_add_one_self  now requires no hypotheses
  3089   real_of_int_add      reversed direction of equality (use [symmetric])
  3090   real_of_int_minus    reversed direction of equality (use [symmetric])
  3091   real_of_int_diff     reversed direction of equality (use [symmetric])
  3092   real_of_int_mult     reversed direction of equality (use [symmetric])
  3093 
  3094 * Theory RComplete: expanded support for floor and ceiling functions.
  3095 
  3096 * Theory Ln is new, with properties of the natural logarithm
  3097 
  3098 * Hyperreal: There is a new type constructor "star" for making
  3099 nonstandard types.  The old type names are now type synonyms:
  3100 
  3101   hypreal = real star
  3102   hypnat = nat star
  3103   hcomplex = complex star
  3104 
  3105 * Hyperreal: Many groups of similarly-defined constants have been
  3106 replaced by polymorphic versions (INCOMPATIBILITY):
  3107 
  3108   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3109 
  3110   starset      <-- starsetNat, starsetC
  3111   *s*          <-- *sNat*, *sc*
  3112   starset_n    <-- starsetNat_n, starsetC_n
  3113   *sn*         <-- *sNatn*, *scn*
  3114   InternalSets <-- InternalNatSets, InternalCSets
  3115 
  3116   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3117   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3118   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3119   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3120   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3121 
  3122 * Hyperreal: Many type-specific theorems have been removed in favor of
  3123 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3124 
  3125   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3126   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3127   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3128   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3129   right_minus <-- hypreal_add_minus
  3130   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3131   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3132   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3133   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3134   mult_1_right <-- hcomplex_mult_one_right
  3135   mult_zero_left <-- hcomplex_mult_zero_left
  3136   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3137   right_distrib <-- hypnat_add_mult_distrib2
  3138   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3139   right_inverse <-- hypreal_mult_inverse
  3140   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3141   order_refl <-- {hypreal,hypnat}_le_refl
  3142   order_trans <-- {hypreal,hypnat}_le_trans
  3143   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3144   order_less_le <-- {hypreal,hypnat}_less_le
  3145   linorder_linear <-- {hypreal,hypnat}_le_linear
  3146   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3147   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3148   add_nonneg_nonneg <-- hypreal_le_add_order
  3149 
  3150 * Hyperreal: Separate theorems having to do with type-specific
  3151 versions of constants have been merged into theorems that apply to the
  3152 new polymorphic constants (INCOMPATIBILITY):
  3153 
  3154   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3155   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3156   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3157   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3158   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3159   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3160   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3161   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3162   STAR_diff <-- {STAR,STARC}_diff
  3163   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3164     STARC_hcomplex_of_complex}_image_subset
  3165   starset_n_Un <-- starset{Nat,C}_n_Un
  3166   starset_n_Int <-- starset{Nat,C}_n_Int
  3167   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3168   starset_n_diff <-- starset{Nat,C}_n_diff
  3169   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3170   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3171   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3172   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3173   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3174   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3175   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3176   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3177   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3178   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3179   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3180   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3181   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3182   starfun_diff <-- starfun{C,RC,CR}_diff
  3183   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3184   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3185   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3186   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3187   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3188   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3189   starfun_Id <-- starfunC_Id
  3190   starfun_approx <-- starfun{Nat,CR}_approx
  3191   starfun_capprox <-- starfun{C,RC}_capprox
  3192   starfun_abs <-- starfunNat_rabs
  3193   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3194   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3195   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3196   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3197   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3198   starfun_add_approx <-- starfunCR_add_approx
  3199   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3200   starfun_divide <-- starfun{C,CR,RC}_divide
  3201   starfun_n <-- starfun{Nat,C}_n
  3202   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3203   starfun_n_add <-- starfun{Nat,C}_n_add
  3204   starfun_n_add_minus <-- starfunNat_n_add_minus
  3205   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3206   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3207   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3208 
  3209   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3210   star_n_minus <-- {hypreal,hcomplex}_minus
  3211   star_n_diff <-- {hypreal,hcomplex}_diff
  3212   star_n_mult <-- {hypreal,hcomplex}_mult
  3213   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3214   star_n_le <-- {hypreal,hypnat}_le
  3215   star_n_less <-- {hypreal,hypnat}_less
  3216   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3217   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3218   star_n_abs <-- hypreal_hrabs
  3219   star_n_divide <-- hcomplex_divide
  3220 
  3221   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3222   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3223   star_of_diff <-- hypreal_of_real_diff
  3224   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3225   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3226   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3227   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3228   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3229   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3230   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3231   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3232   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3233   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3234   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3235   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3236   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3237   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3238   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3239   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3240   star_of_power <-- hypreal_of_real_power
  3241   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3242 
  3243 * Hyperreal: new method "transfer" that implements the transfer
  3244 principle of nonstandard analysis. With a subgoal that mentions
  3245 nonstandard types like "'a star", the command "apply transfer"
  3246 replaces it with an equivalent one that mentions only standard types.
  3247 To be successful, all free variables must have standard types; non-
  3248 standard variables must have explicit universal quantifiers.
  3249 
  3250 * Hyperreal: A theory of Taylor series.
  3251 
  3252 
  3253 *** HOLCF ***
  3254 
  3255 * Discontinued special version of 'constdefs' (which used to support
  3256 continuous functions) in favor of the general Pure one with full
  3257 type-inference.
  3258 
  3259 * New simplification procedure for solving continuity conditions; it
  3260 is much faster on terms with many nested lambda abstractions (cubic
  3261 instead of exponential time).
  3262 
  3263 * New syntax for domain package: selector names are now optional.
  3264 Parentheses should be omitted unless argument is lazy, for example:
  3265 
  3266   domain 'a stream = cons "'a" (lazy "'a stream")
  3267 
  3268 * New command 'fixrec' for defining recursive functions with pattern
  3269 matching; defining multiple functions with mutual recursion is also
  3270 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3271 sinr, or any data constructor defined by the domain package. The given
  3272 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3273 syntax and examples.
  3274 
  3275 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3276 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3277 but the proof obligation additionally includes an admissibility
  3278 requirement. The packages generate instances of class cpo or pcpo,
  3279 with continuity and strictness theorems for Rep and Abs.
  3280 
  3281 * HOLCF: Many theorems have been renamed according to a more standard naming
  3282 scheme (INCOMPATIBILITY):
  3283 
  3284   foo_inject:  "foo$x = foo$y ==> x = y"
  3285   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3286   foo_less:    "(foo$x << foo$y) = (x << y)"
  3287   foo_strict:  "foo$UU = UU"
  3288   foo_defined: "... ==> foo$x ~= UU"
  3289   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3290 
  3291 
  3292 *** ZF ***
  3293 
  3294 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3295 including the First Isomorphism Theorem (on quotienting by the kernel
  3296 of a homomorphism).
  3297 
  3298 * ZF/Simplifier: install second copy of type solver that actually
  3299 makes use of TC rules declared to Isar proof contexts (or locales);
  3300 the old version is still required for ML proof scripts.
  3301 
  3302 
  3303 *** Cube ***
  3304 
  3305 * Converted to Isar theory format; use locales instead of axiomatic
  3306 theories.
  3307 
  3308 
  3309 *** ML ***
  3310 
  3311 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3312 for ||>, ||>>, |>>,
  3313 
  3314 * Pure/library.ML no longer defines its own option datatype, but uses
  3315 that of the SML basis, which has constructors NONE and SOME instead of
  3316 None and Some, as well as exception Option.Option instead of OPTION.
  3317 The functions the, if_none, is_some, is_none have been adapted
  3318 accordingly, while Option.map replaces apsome.
  3319 
  3320 * Pure/library.ML: the exception LIST has been given up in favour of
  3321 the standard exceptions Empty and Subscript, as well as
  3322 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3323 superceded by the standard hd and tl functions etc.
  3324 
  3325 A number of basic list functions are no longer exported to the ML
  3326 toplevel, as they are variants of predefined functions.  The following
  3327 suggests how one can translate existing code:
  3328 
  3329     rev_append xs ys = List.revAppend (xs, ys)
  3330     nth_elem (i, xs) = List.nth (xs, i)
  3331     last_elem xs = List.last xs
  3332     flat xss = List.concat xss
  3333     seq fs = List.app fs
  3334     partition P xs = List.partition P xs
  3335     mapfilter f xs = List.mapPartial f xs
  3336 
  3337 * Pure/library.ML: several combinators for linear functional
  3338 transformations, notably reverse application and composition:
  3339 
  3340   x |> f                f #> g
  3341   (x, y) |-> f          f #-> g
  3342 
  3343 * Pure/library.ML: introduced/changed precedence of infix operators:
  3344 
  3345   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3346   infix 2 ?;
  3347   infix 3 o oo ooo oooo;
  3348   infix 4 ~~ upto downto;
  3349 
  3350 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3351 infix operators.
  3352 
  3353 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3354 fold_map support linear functional transformations and nesting.  For
  3355 example:
  3356 
  3357   fold f [x1, ..., xN] y =
  3358     y |> f x1 |> ... |> f xN
  3359 
  3360   (fold o fold) f [xs1, ..., xsN] y =
  3361     y |> fold f xs1 |> ... |> fold f xsN
  3362 
  3363   fold f [x1, ..., xN] =
  3364     f x1 #> ... #> f xN
  3365 
  3366   (fold o fold) f [xs1, ..., xsN] =
  3367     fold f xs1 #> ... #> fold f xsN
  3368 
  3369 * Pure/library.ML: the following selectors on type 'a option are
  3370 available:
  3371 
  3372   the:               'a option -> 'a  (*partial*)
  3373   these:             'a option -> 'a  where 'a = 'b list
  3374   the_default: 'a -> 'a option -> 'a
  3375   the_list:          'a option -> 'a list
  3376 
  3377 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3378 basic operations for association lists, following natural argument
  3379 order; moreover the explicit equality predicate passed here avoids
  3380 potentially expensive polymorphic runtime equality checks.
  3381 The old functions may be expressed as follows:
  3382 
  3383   assoc = uncurry (AList.lookup (op =))
  3384   assocs = these oo AList.lookup (op =)
  3385   overwrite = uncurry (AList.update (op =)) o swap
  3386 
  3387 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3388 
  3389   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3390   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3391 
  3392 replacing make_keylist and keyfilter (occassionally used)
  3393 Naive rewrites:
  3394 
  3395   make_keylist = AList.make
  3396   keyfilter = AList.find (op =)
  3397 
  3398 * eq_fst and eq_snd now take explicit equality parameter, thus
  3399   avoiding eqtypes. Naive rewrites:
  3400 
  3401     eq_fst = eq_fst (op =)
  3402     eq_snd = eq_snd (op =)
  3403 
  3404 * Removed deprecated apl and apr (rarely used).
  3405   Naive rewrites:
  3406 
  3407     apl (n, op) =>>= curry op n
  3408     apr (op, m) =>>= fn n => op (n, m)
  3409 
  3410 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3411 provides a reasonably efficient light-weight implementation of sets as
  3412 lists.
  3413 
  3414 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3415 few new operations; existing lookup and update are now curried to
  3416 follow natural argument order (for use with fold etc.);
  3417 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3418 
  3419 * Pure/General: output via the Isabelle channels of
  3420 writeln/warning/error etc. is now passed through Output.output, with a
  3421 hook for arbitrary transformations depending on the print_mode
  3422 (cf. Output.add_mode -- the first active mode that provides a output
  3423 function wins).  Already formatted output may be embedded into further
  3424 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3425 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3426 accommodate easy composition of diagnostic messages etc.  Programmers
  3427 rarely need to care about Output.output or Output.raw at all, with
  3428 some notable exceptions: Output.output is required when bypassing the
  3429 standard channels (writeln etc.), or in token translations to produce
  3430 properly formatted results; Output.raw is required when capturing
  3431 already output material that will eventually be presented to the user
  3432 a second time.  For the default print mode, both Output.output and
  3433 Output.raw have no effect.
  3434 
  3435 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3436 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3437 cumulative results are displayed at the end of a batch session.
  3438 
  3439 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3440 replaced by File.platform_path and File.shell_path (with appropriate
  3441 hooks).  This provides a clean interface for unusual systems where the
  3442 internal and external process view of file names are different.
  3443 
  3444 * Pure: more efficient orders for basic syntactic entities: added
  3445 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3446 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3447 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3448 orders now -- potential INCOMPATIBILITY for code that depends on a
  3449 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3450 Library.sort_strings on result).
  3451 
  3452 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3453 fold_types traverse types/terms from left to right, observing natural
  3454 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3455 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3456 
  3457 * Pure: name spaces have been refined, with significant changes of the
  3458 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3459 to extern(_table).  The plain name entry path is superceded by a
  3460 general 'naming' context, which also includes the 'policy' to produce
  3461 a fully qualified name and external accesses of a fully qualified
  3462 name; NameSpace.extend is superceded by context dependent
  3463 Sign.declare_name.  Several theory and proof context operations modify
  3464 the naming context.  Especially note Theory.restore_naming and
  3465 ProofContext.restore_naming to get back to a sane state; note that
  3466 Theory.add_path is no longer sufficient to recover from
  3467 Theory.absolute_path in particular.
  3468 
  3469 * Pure: new flags short_names (default false) and unique_names
  3470 (default true) for controlling output of qualified names.  If
  3471 short_names is set, names are printed unqualified.  If unique_names is
  3472 reset, the name prefix is reduced to the minimum required to achieve
  3473 the original result when interning again, even if there is an overlap
  3474 with earlier declarations.
  3475 
  3476 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3477 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3478 (useful for printing error messages).  INCOMPATIBILITY.
  3479 
  3480 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3481 Theory.theory are now identified, referring to the universal
  3482 Context.theory (see Pure/context.ML).  Actual signature and theory
  3483 content is managed as theory data.  The old code and interfaces were
  3484 spread over many files and structures; the new arrangement introduces
  3485 considerable INCOMPATIBILITY to gain more clarity:
  3486 
  3487   Context -- theory management operations (name, identity, inclusion,
  3488     parents, ancestors, merge, etc.), plus generic theory data;
  3489 
  3490   Sign -- logical signature and syntax operations (declaring consts,
  3491     types, etc.), plus certify/read for common entities;
  3492 
  3493   Theory -- logical theory operations (stating axioms, definitions,
  3494     oracles), plus a copy of logical signature operations (consts,
  3495     types, etc.); also a few basic management operations (Theory.copy,
  3496     Theory.merge, etc.)
  3497 
  3498 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3499 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3500 for convenience -- they merely return the theory.
  3501 
  3502 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3503 
  3504 * Pure: the Isar proof context type is already defined early in Pure
  3505 as Context.proof (note that ProofContext.context and Proof.context are
  3506 aliases, where the latter is the preferred name).  This enables other
  3507 Isabelle components to refer to that type even before Isar is present.
  3508 
  3509 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3510 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3511 any of these kinds.  For example, Sign.intern typeK is now
  3512 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3513 Theory.hide_types.  Also note that former
  3514 Theory.hide_classes/types/consts are now
  3515 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3516 internalize their arguments!  INCOMPATIBILITY.
  3517 
  3518 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3519 datatype thmref (with constructors Name and NameSelection) instead of
  3520 plain string -- INCOMPATIBILITY;
  3521 
  3522 * Pure: cases produced by proof methods specify options, where NONE
  3523 means to remove case bindings -- INCOMPATIBILITY in
  3524 (RAW_)METHOD_CASES.
  3525 
  3526 * Pure: the following operations retrieve axioms or theorems from a
  3527 theory node or theory hierarchy, respectively:
  3528 
  3529   Theory.axioms_of: theory -> (string * term) list
  3530   Theory.all_axioms_of: theory -> (string * term) list
  3531   PureThy.thms_of: theory -> (string * thm) list
  3532   PureThy.all_thms_of: theory -> (string * thm) list
  3533 
  3534 * Pure: print_tac now outputs the goal through the trace channel.
  3535 
  3536 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3537 Reference Toplevel.debug (default false) controls detailed printing
  3538 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3539 controls execution profiling -- set to 1 for time and 2 for space
  3540 (both increase the runtime).
  3541 
  3542 * Isar session: The initial use of ROOT.ML is now always timed,
  3543 i.e. the log will show the actual process times, in contrast to the
  3544 elapsed wall-clock time that the outer shell wrapper produces.
  3545 
  3546 * Simplifier: improved handling of bound variables (nameless
  3547 representation, avoid allocating new strings).  Simprocs that invoke
  3548 the Simplifier recursively should use Simplifier.inherit_bounds to
  3549 avoid local name clashes.  Failure to do so produces warnings
  3550 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3551 for further details.
  3552 
  3553 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3554 bindings for all theorems stored within a given theory; this may help
  3555 in porting non-Isar theories to Isar ones, while keeping ML proof
  3556 scripts for the time being.
  3557 
  3558 * ML operator HTML.with_charset specifies the charset begin used for
  3559 generated HTML files.  For example:
  3560 
  3561   HTML.with_charset "utf-8" use_thy "Hebrew";
  3562   HTML.with_charset "utf-8" use_thy "Chinese";
  3563 
  3564 
  3565 *** System ***
  3566 
  3567 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3568 isabelle, isatool etc.).
  3569 
  3570 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3571 isatool doc, isatool mkdir, display_drafts etc.).
  3572 
  3573 * isatool usedir: option -f allows specification of the ML file to be
  3574 used by Isabelle; default is ROOT.ML.
  3575 
  3576 * New isatool version outputs the version identifier of the Isabelle
  3577 distribution being used.
  3578 
  3579 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3580 (containing Boolean satisfiability problems) into Isabelle/HOL
  3581 theories.
  3582 
  3583 
  3584 
  3585 New in Isabelle2004 (April 2004)
  3586 --------------------------------
  3587 
  3588 *** General ***
  3589 
  3590 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3591   Replaces linorder.ML.
  3592 
  3593 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3594   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3595   (\<a>...\<z>), are now considered normal letters, and can therefore
  3596   be used anywhere where an ASCII letter (a...zA...Z) has until
  3597   now. COMPATIBILITY: This obviously changes the parsing of some
  3598   terms, especially where a symbol has been used as a binder, say
  3599   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3600   as an identifier.  Fix it by inserting a space around former
  3601   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3602   existing theory and ML files.
  3603 
  3604 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3605 
  3606 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3607   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3608   a normal (but invisible) letter. For multiple letter subscripts repeat
  3609   \<^isub> like this: x\<^isub>1\<^isub>2.
  3610 
  3611 * Pure: There are now sub-/superscripts that can span more than one
  3612   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3613   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3614   superscript. The new control characters are not identifier parts.
  3615 
  3616 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3617   content of "..." to the latex file instead of \isacntrl... . The "..."
  3618   may consist of any printable characters excluding the end bracket >.
  3619 
  3620 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3621   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3622   declare constants "final", which prevents their being given a definition
  3623   later.  It is useful for constants whose behaviour is fixed axiomatically
  3624   rather than definitionally, such as the meta-logic connectives.
  3625 
  3626 * Pure: 'instance' now handles general arities with general sorts
  3627   (i.e. intersections of classes),
  3628 
  3629 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3630   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3631   It can be changed to alter the colors/layout of generated pages.
  3632 
  3633 
  3634 *** Isar ***
  3635 
  3636 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3637   cut_tac, subgoal_tac and thin_tac:
  3638   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3639     locales are no longer forced to write Isar proof scripts.
  3640     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3641     emulations.
  3642   - INCOMPATIBILITY: names of variables to be instantiated may no
  3643     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3644     This is consistent with the instantiation attribute "where".
  3645 
  3646 * Attributes "where" and "of":
  3647   - Now take type variables of instantiated theorem into account when reading
  3648     the instantiation string.  This fixes a bug that caused instantiated
  3649     theorems to have too special types in some circumstances.
  3650   - "where" permits explicit instantiations of type variables.
  3651 
  3652 * Calculation commands "moreover" and "also" no longer interfere with
  3653   current facts ("this"), admitting arbitrary combinations with "then"
  3654   and derived forms.
  3655 
  3656 * Locales:
  3657   - Goal statements involving the context element "includes" no longer
  3658     generate theorems with internal delta predicates (those ending on
  3659     "_axioms") in the premise.
  3660     Resolve particular premise with <locale>.intro to obtain old form.
  3661   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3662     specification and "includes" elements in goal statement.
  3663   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3664     [intro?] and [elim?] (respectively) by default.
  3665   - Experimental command for instantiation of locales in proof contexts:
  3666         instantiate <label>[<attrs>]: <loc>
  3667     Instantiates locale <loc> and adds all its theorems to the current context
  3668     taking into account their attributes.  Label and attrs are optional
  3669     modifiers, like in theorem declarations.  If present, names of
  3670     instantiated theorems are qualified with <label>, and the attributes
  3671     <attrs> are applied after any attributes these theorems might have already.
  3672       If the locale has assumptions, a chained fact of the form
  3673     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3674     are derived.  The command does not support old-style locales declared
  3675     with "locale (open)".
  3676       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3677 
  3678 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3679   (Isar) contexts.
  3680 
  3681 
  3682 *** HOL ***
  3683 
  3684 * Proof import: new image HOL4 contains the imported library from
  3685   the HOL4 system with about 2500 theorems. It is imported by
  3686   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3687   can be used like any other Isabelle image.  See
  3688   HOL/Import/HOL/README for more information.
  3689 
  3690 * Simplifier:
  3691   - Much improved handling of linear and partial orders.
  3692     Reasoners for linear and partial orders are set up for type classes
  3693     "linorder" and "order" respectively, and are added to the default simpset
  3694     as solvers.  This means that the simplifier can build transitivity chains
  3695     to solve goals from the assumptions.
  3696   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3697     of blast or auto after simplification become unnecessary because the goal
  3698     is solved by simplification already.
  3699 
  3700 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3701     all proved in axiomatic type classes for semirings, rings and fields.
  3702 
  3703 * Numerics:
  3704   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3705     now formalized using the Ring_and_Field theory mentioned above.
  3706   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3707     than before, because now they are set up once in a generic manner.
  3708   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3709     Look for the general versions in Ring_and_Field (and Power if they concern
  3710     exponentiation).
  3711 
  3712 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3713 
  3714 * Records:
  3715   - Record types are now by default printed with their type abbreviation
  3716     instead of the list of all field types. This can be configured via
  3717     the reference "print_record_type_abbr".
  3718   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3719     (not enabled by default).
  3720   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3721     EX x. x = sel r to True (not enabled by default).
  3722   - Tactic "record_split_simp_tac" to split and simplify records added.
  3723 
  3724 * 'specification' command added, allowing for definition by
  3725   specification.  There is also an 'ax_specification' command that
  3726   introduces the new constants axiomatically.
  3727 
  3728 * arith(_tac) is now able to generate counterexamples for reals as well.
  3729 
  3730 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3731 
  3732 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3733   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3734 
  3735 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3736   matrix theory to linear programming.
  3737 
  3738 * Unions and Intersections:
  3739   The latex output syntax of UN and INT has been changed
  3740   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3741   i.e. the index formulae has become a subscript.
  3742   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3743 
  3744 * Unions and Intersections over Intervals:
  3745   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3746   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3747   like in normal math, and corresponding versions for < and for intersection.
  3748 
  3749 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3750   lexicographic dictonary ordering has been added as "lexord".
  3751 
  3752 * ML: the legacy theory structures Int and List have been removed. They had
  3753   conflicted with ML Basis Library structures having the same names.
  3754 
  3755 * 'refute' command added to search for (finite) countermodels.  Only works
  3756   for a fragment of HOL.  The installation of an external SAT solver is
  3757   highly recommended.  See "HOL/Refute.thy" for details.
  3758 
  3759 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3760   formulae under an assignment of free variables to random values.
  3761   In contrast to 'refute', it can deal with inductive datatypes,
  3762   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3763   for examples.
  3764 
  3765 
  3766 *** HOLCF ***
  3767 
  3768 * Streams now come with concatenation and are part of the HOLCF image
  3769 
  3770 
  3771 
  3772 New in Isabelle2003 (May 2003)
  3773 ------------------------------
  3774 
  3775 *** General ***
  3776 
  3777 * Provers/simplifier:
  3778 
  3779   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3780     Assumptions are now subject to complete mutual simplification,
  3781     not just from left to right. The simplifier now preserves
  3782     the order of assumptions.
  3783 
  3784     Potential INCOMPATIBILITY:
  3785 
  3786     -- simp sometimes diverges where the old version did
  3787        not, e.g. invoking simp on the goal
  3788 
  3789         [| P (f x); y = x; f x = f y |] ==> Q
  3790 
  3791        now gives rise to the infinite reduction sequence
  3792 
  3793         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3794 
  3795        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3796        kind of problem.
  3797 
  3798     -- Tactics combining classical reasoner and simplification (such as auto)
  3799        are also affected by this change, because many of them rely on
  3800        simp. They may sometimes diverge as well or yield a different numbers
  3801        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3802        in case of problems. Sometimes subsequent calls to the classical
  3803        reasoner will fail because a preceeding call to the simplifier too
  3804        eagerly simplified the goal, e.g. deleted redundant premises.
  3805 
  3806   - The simplifier trace now shows the names of the applied rewrite rules
  3807 
  3808   - You can limit the number of recursive invocations of the simplifier
  3809     during conditional rewriting (where the simplifie tries to solve the
  3810     conditions before applying the rewrite rule):
  3811     ML "simp_depth_limit := n"
  3812     where n is an integer. Thus you can force termination where previously
  3813     the simplifier would diverge.
  3814 
  3815   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3816 
  3817   - No longer aborts on failed congruence proof.  Instead, the
  3818     congruence is ignored.
  3819 
  3820 * Pure: New generic framework for extracting programs from constructive
  3821   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3822   as HOL/Extraction for some case studies.
  3823 
  3824 * Pure: The main goal of the proof state is no longer shown by default, only
  3825 the subgoals. This behaviour is controlled by a new flag.
  3826    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3827 (ML: Proof.show_main_goal).
  3828 
  3829 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3830 rules whose conclusion matches subgoal 1:
  3831       PG menu: Isabelle/Isar -> Show me -> matching rules
  3832 The rules are ordered by how closely they match the subgoal.
  3833 In particular, rules that solve a subgoal outright are displayed first
  3834 (or rather last, the way they are printed).
  3835 (ML: ProofGeneral.print_intros())
  3836 
  3837 * Pure: New flag trace_unify_fail causes unification to print
  3838 diagnostic information (PG: in trace buffer) when it fails. This is
  3839 useful for figuring out why single step proofs like rule, erule or
  3840 assumption failed.
  3841 
  3842 * Pure: Locale specifications now produce predicate definitions
  3843 according to the body of text (covering assumptions modulo local
  3844 definitions); predicate "loc_axioms" covers newly introduced text,
  3845 while "loc" is cumulative wrt. all included locale expressions; the
  3846 latter view is presented only on export into the global theory
  3847 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3848 on the old view without predicates;
  3849 
  3850 * Pure: predefined locales "var" and "struct" are useful for sharing
  3851 parameters (as in CASL, for example); just specify something like
  3852 ``var x + var y + struct M'' as import;
  3853 
  3854 * Pure: improved thms_containing: proper indexing of facts instead of
  3855 raw theorems; check validity of results wrt. current name space;
  3856 include local facts of proof configuration (also covers active
  3857 locales), cover fixed variables in index; may use "_" in term
  3858 specification; an optional limit for the number of printed facts may
  3859 be given (the default is 40);
  3860 
  3861 * Pure: disallow duplicate fact bindings within new-style theory files
  3862 (batch-mode only);
  3863 
  3864 * Provers: improved induct method: assumptions introduced by case
  3865 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3866 the goal statement); "foo" still refers to all facts collectively;
  3867 
  3868 * Provers: the function blast.overloaded has been removed: all constants
  3869 are regarded as potentially overloaded, which improves robustness in exchange
  3870 for slight decrease in efficiency;
  3871 
  3872 * Provers/linorder: New generic prover for transitivity reasoning over
  3873 linear orders.  Note: this prover is not efficient!
  3874 
  3875 * Isar: preview of problems to finish 'show' now produce an error
  3876 rather than just a warning (in interactive mode);
  3877 
  3878 
  3879 *** HOL ***
  3880 
  3881 * arith(_tac)
  3882 
  3883  - Produces a counter example if it cannot prove a goal.
  3884    Note that the counter example may be spurious if the goal is not a formula
  3885    of quantifier-free linear arithmetic.
  3886    In ProofGeneral the counter example appears in the trace buffer.
  3887 
  3888  - Knows about div k and mod k where k is a numeral of type nat or int.
  3889 
  3890  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3891    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3892    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3893 
  3894 * simp's arithmetic capabilities have been enhanced a bit: it now
  3895 takes ~= in premises into account (by performing a case split);
  3896 
  3897 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3898 are distributed over a sum of terms;
  3899 
  3900 * New tactic "trans_tac" and method "trans" instantiate
  3901 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3902 "<=", "<" and "=").
  3903 
  3904 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3905 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3906 
  3907 * 'typedef' command has new option "open" to suppress the set
  3908 definition;
  3909 
  3910 * functions Min and Max on finite sets have been introduced (theory
  3911 Finite_Set);
  3912 
  3913 * attribute [symmetric] now works for relations as well; it turns
  3914 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3915 
  3916 * induct over a !!-quantified statement (say !!x1..xn):
  3917   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3918 
  3919 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3920 %x. None. Warning: empty_def now refers to the previously hidden definition
  3921 of the empty set.
  3922 
  3923 * Algebra: formalization of classical algebra.  Intended as base for
  3924 any algebraic development in Isabelle.  Currently covers group theory
  3925 (up to Sylow's theorem) and ring theory (Universal Property of
  3926 Univariate Polynomials).  Contributions welcome;
  3927 
  3928 * GroupTheory: deleted, since its material has been moved to Algebra;
  3929 
  3930 * Complex: new directory of the complex numbers with numeric constants,
  3931 nonstandard complex numbers, and some complex analysis, standard and
  3932 nonstandard (Jacques Fleuriot);
  3933 
  3934 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3935 
  3936 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3937 Fleuriot);
  3938 
  3939 * Real/HahnBanach: updated and adapted to locales;
  3940 
  3941 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3942 Gray and Kramer);
  3943 
  3944 * UNITY: added the Meier-Sanders theory of progress sets;
  3945 
  3946 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3947 as abstract algorithms, instantiated to the JVM;
  3948 
  3949 * Bali: Java source language formalization. Type system, operational
  3950 semantics, axiomatic semantics. Supported language features:
  3951 classes, interfaces, objects,virtual methods, static methods,
  3952 static/instance fields, arrays, access modifiers, definite
  3953 assignment, exceptions.
  3954 
  3955 
  3956 *** ZF ***
  3957 
  3958 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3959 universe, etc.);
  3960 
  3961 * Main ZF: virtually all theories converted to new-style format;
  3962 
  3963 
  3964 *** ML ***
  3965 
  3966 * Pure: Tactic.prove provides sane interface for internal proofs;
  3967 omits the infamous "standard" operation, so this is more appropriate
  3968 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3969 
  3970 * Pure: improved error reporting of simprocs;
  3971 
  3972 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3973 up simprocs;
  3974 
  3975 
  3976 *** Document preparation ***
  3977 
  3978 * uses \par instead of \\ for line breaks in theory text. This may
  3979 shift some page breaks in large documents. To get the old behaviour
  3980 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3981 
  3982 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3983 other packages
  3984 
  3985 * \<euro> now needs package babel/greek instead of marvosym (which
  3986 broke \Rightarrow)
  3987 
  3988 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3989 textcomp package)
  3990 
  3991 
  3992 
  3993 New in Isabelle2002 (March 2002)
  3994 --------------------------------
  3995 
  3996 *** Document preparation ***
  3997 
  3998 * greatly simplified document preparation setup, including more
  3999 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4000 instructive isatool mkdir; users should basically be able to get
  4001 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4002 users may run a separate document processing stage manually like this:
  4003 "isatool usedir -D output HOL Test && isatool document Test/output";
  4004 
  4005 * theory dependency graph may now be incorporated into documents;
  4006 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4007 with \includegraphics of LaTeX;
  4008 
  4009 * proper spacing of consecutive markup elements, especially text
  4010 blocks after section headings;
  4011 
  4012 * support bold style (for single symbols only), input syntax is like
  4013 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4014 
  4015 * \<bullet> is now output as bold \cdot by default, which looks much
  4016 better in printed text;
  4017 
  4018 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4019 note that these symbols are currently unavailable in Proof General /
  4020 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4021 
  4022 * isatool latex no longer depends on changed TEXINPUTS, instead
  4023 isatool document copies the Isabelle style files to the target
  4024 location;
  4025 
  4026 
  4027 *** Isar ***
  4028 
  4029 * Pure/Provers: improved proof by cases and induction;
  4030   - 'case' command admits impromptu naming of parameters (such as
  4031     "case (Suc n)");
  4032   - 'induct' method divinates rule instantiation from the inductive
  4033     claim; no longer requires excessive ?P bindings for proper
  4034     instantiation of cases;
  4035   - 'induct' method properly enumerates all possibilities of set/type
  4036     rules; as a consequence facts may be also passed through *type*
  4037     rules without further ado;
  4038   - 'induct' method now derives symbolic cases from the *rulified*
  4039     rule (before it used to rulify cases stemming from the internal
  4040     atomized version); this means that the context of a non-atomic
  4041     statement becomes is included in the hypothesis, avoiding the
  4042     slightly cumbersome show "PROP ?case" form;
  4043   - 'induct' may now use elim-style induction rules without chaining
  4044     facts, using ``missing'' premises from the goal state; this allows
  4045     rules stemming from inductive sets to be applied in unstructured
  4046     scripts, while still benefitting from proper handling of non-atomic
  4047     statements; NB: major inductive premises need to be put first, all
  4048     the rest of the goal is passed through the induction;
  4049   - 'induct' proper support for mutual induction involving non-atomic
  4050     rule statements (uses the new concept of simultaneous goals, see
  4051     below);
  4052   - append all possible rule selections, but only use the first
  4053     success (no backtracking);
  4054   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4055   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4056   - added 'print_induct_rules' (covered by help item in recent Proof
  4057     General versions);
  4058   - moved induct/cases attributes to Pure, methods to Provers;
  4059   - generic method setup instantiated for FOL and HOL;
  4060 
  4061 * Pure: support multiple simultaneous goal statements, for example
  4062 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4063 meta-level mechanism, this acts as if several individual goals had
  4064 been stated separately; in particular common proof methods need to be
  4065 repeated in order to cover all claims; note that a single elimination
  4066 step is *not* sufficient to establish the two conjunctions, so this
  4067 fails:
  4068 
  4069   assume "A & B" then have A and B ..   (*".." fails*)
  4070 
  4071 better use "obtain" in situations as above; alternative refer to
  4072 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4073 
  4074 * Pure: proper integration with ``locales''; unlike the original
  4075 version by Florian Kammller, Isar locales package high-level proof
  4076 contexts rather than raw logical ones (e.g. we admit to include
  4077 attributes everywhere); operations on locales include merge and
  4078 rename; support for implicit arguments (``structures''); simultaneous
  4079 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4080 some examples;
  4081 
  4082 * Pure: the following commands have been ``localized'', supporting a
  4083 target locale specification "(in name)": 'lemma', 'theorem',
  4084 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4085 stored both within the locale and at the theory level (exported and
  4086 qualified by the locale name);
  4087 
  4088 * Pure: theory goals may now be specified in ``long'' form, with
  4089 ad-hoc contexts consisting of arbitrary locale elements. for example
  4090 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4091 definitions may be given, too); the result is a meta-level rule with
  4092 the context elements being discharged in the obvious way;
  4093 
  4094 * Pure: new proof command 'using' allows to augment currently used
  4095 facts after a goal statement ('using' is syntactically analogous to
  4096 'apply', but acts on the goal's facts only); this allows chained facts
  4097 to be separated into parts given before and after a claim, as in
  4098 ``from a and b have C using d and e <proof>'';
  4099 
  4100 * Pure: renamed "antecedent" case to "rule_context";
  4101 
  4102 * Pure: new 'judgment' command records explicit information about the
  4103 object-logic embedding (used by several tools internally); no longer
  4104 use hard-wired "Trueprop";
  4105 
  4106 * Pure: added 'corollary' command;
  4107 
  4108 * Pure: fixed 'token_translation' command;
  4109 
  4110 * Pure: removed obsolete 'exported' attribute;
  4111 
  4112 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4113 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4114 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4115 
  4116 * Pure: method 'atomize' presents local goal premises as object-level
  4117 statements (atomic meta-level propositions); setup controlled via
  4118 rewrite rules declarations of 'atomize' attribute; example
  4119 application: 'induct' method with proper rule statements in improper
  4120 proof *scripts*;
  4121 
  4122 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4123 now consider the syntactic context of assumptions, giving a better
  4124 chance to get type-inference of the arguments right (this is
  4125 especially important for locales);
  4126 
  4127 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4128 mode;
  4129 
  4130 * Pure/obtain: the formal conclusion "thesis", being marked as
  4131 ``internal'', may no longer be reference directly in the text;
  4132 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4133 situations;
  4134 
  4135 * Pure: generic 'sym' attribute which declares a rule both as pure
  4136 'elim?' and for the 'symmetric' operation;
  4137 
  4138 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4139 text; the fixed correlation with particular command syntax has been
  4140 discontinued;
  4141 
  4142 * Pure: new method 'rules' is particularly well-suited for proof
  4143 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4144 but often produces more compact proof terms with less detours;
  4145 
  4146 * Pure/Provers/classical: simplified integration with pure rule
  4147 attributes and methods; the classical "intro?/elim?/dest?"
  4148 declarations coincide with the pure ones; the "rule" method no longer
  4149 includes classically swapped intros; "intro" and "elim" methods no
  4150 longer pick rules from the context; also got rid of ML declarations
  4151 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4152 INCOMPATIBILITY;
  4153 
  4154 * Provers/classical: attribute 'swapped' produces classical inversions
  4155 of introduction rules;
  4156 
  4157 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4158 rules instead of full simplifier context; 'iff' attribute handles
  4159 conditional rules;
  4160 
  4161 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4162 
  4163 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4164 "(permissive)" option to recover old behavior;
  4165 
  4166 * HOL: 'inductive' no longer features separate (collective) attributes
  4167 for 'intros' (was found too confusing);
  4168 
  4169 * HOL: properly declared induction rules less_induct and
  4170 wf_induct_rule;
  4171 
  4172 
  4173 *** HOL ***
  4174 
  4175 * HOL: moved over to sane numeral syntax; the new policy is as
  4176 follows:
  4177 
  4178   - 0 and 1 are polymorphic constants, which are defined on any
  4179   numeric type (nat, int, real etc.);
  4180 
  4181   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4182   binary representation internally;
  4183 
  4184   - type nat has special constructor Suc, and generally prefers Suc 0
  4185   over 1::nat and Suc (Suc 0) over 2::nat;
  4186 
  4187 This change may cause significant problems of INCOMPATIBILITY; here
  4188 are some hints on converting existing sources:
  4189 
  4190   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4191   entities, so expressions involving "-" (unary or binary minus) need
  4192   to be spaced properly;
  4193 
  4194   - existing occurrences of "1" may need to be constraint "1::nat" or
  4195   even replaced by Suc 0; similar for old "2";
  4196 
  4197   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4198 
  4199   - remove all special provisions on numerals in proofs;
  4200 
  4201 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4202 representation (depends on bin_arith_simps in the default context);
  4203 
  4204 * HOL: symbolic syntax for x^2 (numeral 2);
  4205 
  4206 * HOL: the class of all HOL types is now called "type" rather than
  4207 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4208 in axclass/classes, instance/arities, and (usually rare) occurrences
  4209 in typings (of consts etc.); internally the class is called
  4210 "HOL.type", ML programs should refer to HOLogic.typeS;
  4211 
  4212 * HOL/record package improvements:
  4213   - new derived operations "fields" to build a partial record section,
  4214     "extend" to promote a fixed record to a record scheme, and
  4215     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4216     declared as simp by default;
  4217   - shared operations ("more", "fields", etc.) now need to be always
  4218     qualified) --- potential INCOMPATIBILITY;
  4219   - removed "make_scheme" operations (use "make" with "extend") --
  4220     INCOMPATIBILITY;
  4221   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4222   - provides cases/induct rules for use with corresponding Isar
  4223     methods (for concrete records, record schemes, concrete more
  4224     parts, and schematic more parts -- in that order);
  4225   - internal definitions directly based on a light-weight abstract
  4226     theory of product types over typedef rather than datatype;
  4227 
  4228 * HOL: generic code generator for generating executable ML code from
  4229 specifications; specific support for HOL constructs such as inductive
  4230 datatypes and sets, as well as recursive functions; can be invoked
  4231 via 'generate_code' theory section;
  4232 
  4233 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4234 
  4235 * HOL: consolidated and renamed several theories.  In particular:
  4236         Ord.thy has been absorbed into HOL.thy
  4237         String.thy has been absorbed into List.thy
  4238 
  4239 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4240 (beware of argument permutation!);
  4241 
  4242 * HOL: linorder_less_split superseded by linorder_cases;
  4243 
  4244 * HOL/List: "nodups" renamed to "distinct";
  4245 
  4246 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4247 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4248   - Ex_def has changed, now need to use some_eq_ex
  4249 
  4250 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4251 in this (rare) case use:
  4252 
  4253   delSWrapper "split_all_tac"
  4254   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4255 
  4256 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4257 MAY FAIL;
  4258 
  4259 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4260 Isabelle's type classes, ^ on functions and relations has too general
  4261 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4262 necessary to attach explicit type constraints;
  4263 
  4264 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4265 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4266 renamed accordingly (eg "compI" -> "rel_compI").
  4267 
  4268 * HOL: syntax translations now work properly with numerals and records
  4269 expressions;
  4270 
  4271 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4272 of "lam" -- INCOMPATIBILITY;
  4273 
  4274 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4275 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4276 renamed "Product_Type.unit";
  4277 
  4278 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4279 
  4280 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4281 the "cases" method);
  4282 
  4283 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4284 Florian Kammller);
  4285 
  4286 * HOL/IMP: updated and converted to new-style theory format; several
  4287 parts turned into readable document, with proper Isar proof texts and
  4288 some explanations (by Gerwin Klein);
  4289 
  4290 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4291 
  4292 * HOL-Hyperreal is now a logic image;
  4293 
  4294 
  4295 *** HOLCF ***
  4296 
  4297 * Isar: consts/constdefs supports mixfix syntax for continuous
  4298 operations;
  4299 
  4300 * Isar: domain package adapted to new-style theory format, e.g. see
  4301 HOLCF/ex/Dnat.thy;
  4302 
  4303 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4304 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4305 lift.induct_tac, always use UU instead of Undef;
  4306 
  4307 * HOLCF/IMP: updated and converted to new-style theory;
  4308 
  4309 
  4310 *** ZF ***
  4311 
  4312 * Isar: proper integration of logic-specific tools and packages,
  4313 including theory commands '(co)inductive', '(co)datatype',
  4314 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4315 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4316 
  4317 * theory Main no longer includes AC; for the Axiom of Choice, base
  4318 your theory on Main_ZFC;
  4319 
  4320 * the integer library now covers quotients and remainders, with many
  4321 laws relating division to addition, multiplication, etc.;
  4322 
  4323 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4324 typeless version of the formalism;
  4325 
  4326 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4327 format;
  4328 
  4329 * ZF/Induct: new directory for examples of inductive definitions,
  4330 including theory Multiset for multiset orderings; converted to
  4331 new-style theory format;
  4332 
  4333 * ZF: many new theorems about lists, ordinals, etc.;
  4334 
  4335 
  4336 *** General ***
  4337 
  4338 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4339 variable proof controls level of detail: 0 = no proofs (only oracle
  4340 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4341 also ref manual for further ML interfaces;
  4342 
  4343 * Pure/axclass: removed obsolete ML interface
  4344 goal_subclass/goal_arity;
  4345 
  4346 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4347 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4348 separate tokens, so expressions involving minus need to be spaced
  4349 properly;
  4350 
  4351 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4352 rather than "infixl" or "infixr";
  4353 
  4354 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4355 sort constraint specifications in type inference; e.g. "x::_::foo"
  4356 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4357 type variable);
  4358 
  4359 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4360 control output of nested => (types); the default behavior is
  4361 "type_brackets";
  4362 
  4363 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4364 tokens into AST constants;
  4365 
  4366 * Pure/syntax: prefer later declarations of translations and print
  4367 translation functions; potential INCOMPATIBILITY: need to reverse
  4368 multiple declarations for same syntax element constant;
  4369 
  4370 * Pure/show_hyps reset by default (in accordance to existing Isar
  4371 practice);
  4372 
  4373 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4374 addSafter;
  4375 
  4376 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4377 as well;
  4378 
  4379 * system: tested support for MacOS X; should be able to get Isabelle +
  4380 Proof General to work in a plain Terminal after installing Poly/ML
  4381 (e.g. from the Isabelle distribution area) and GNU bash alone
  4382 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4383 support requires further installations, e.g. from
  4384 http://fink.sourceforge.net/);
  4385 
  4386 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4387 
  4388 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4389 of 40 MB), cf. ML_OPTIONS;
  4390 
  4391 * system: Proof General keywords specification is now part of the
  4392 Isabelle distribution (see etc/isar-keywords.el);
  4393 
  4394 * system: support for persistent Proof General sessions (refrain from
  4395 outdating all loaded theories on startup); user may create writable
  4396 logic images like this: ``isabelle -q HOL Test'';
  4397 
  4398 * system: smart selection of Isabelle process versus Isabelle
  4399 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4400 run both "isabelle" and "Isabelle" even if file names are badly
  4401 damaged (executable inspects the case of the first letter of its own
  4402 name); added separate "isabelle-process" and "isabelle-interface";
  4403 
  4404 * system: refrain from any attempt at filtering input streams; no
  4405 longer support ``8bit'' encoding of old isabelle font, instead proper
  4406 iso-latin characters may now be used; the related isatools
  4407 "symbolinput" and "nonascii" have disappeared as well;
  4408 
  4409 * system: removed old "xterm" interface (the print modes "xterm" and
  4410 "xterm_color" are still available for direct use in a suitable
  4411 terminal);
  4412 
  4413 
  4414 
  4415 New in Isabelle99-2 (February 2001)
  4416 -----------------------------------
  4417 
  4418 *** Overview of INCOMPATIBILITIES ***
  4419 
  4420 * HOL: please note that theories in the Library and elsewhere often use the
  4421 new-style (Isar) format; to refer to their theorems in an ML script you must
  4422 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4423 
  4424 * HOL: inductive package no longer splits induction rule aggressively,
  4425 but only as far as specified by the introductions given; the old
  4426 format may be recovered via ML function complete_split_rule or attribute
  4427 'split_rule (complete)';
  4428 
  4429 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4430 gfp_Tarski to gfp_unfold;
  4431 
  4432 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4433 
  4434 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4435 relation); infix "^^" has been renamed "``"; infix "``" has been
  4436 renamed "`"; "univalent" has been renamed "single_valued";
  4437 
  4438 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4439 operation;
  4440 
  4441 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4442 
  4443 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4444 
  4445 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4446 consequence, it is no longer monotonic wrt. the local goal context
  4447 (which is now passed through the inductive cases);
  4448 
  4449 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4450 \<gg> to \<ggreater>;
  4451 
  4452 
  4453 *** Document preparation ***
  4454 
  4455 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4456 available: are "it" for near math-mode best-style output, "sl" for
  4457 slanted text style, and "tt" for plain type-writer; if no
  4458 \isabellestyle command is given, output is according to slanted
  4459 type-writer);
  4460 
  4461 * support sub/super scripts (for single symbols only), input syntax is
  4462 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4463 
  4464 * some more standard symbols; see Appendix A of the system manual for
  4465 the complete list of symbols defined in isabellesym.sty;
  4466 
  4467 * improved isabelle style files; more abstract symbol implementation
  4468 (should now use \isamath{...} and \isatext{...} in custom symbol
  4469 definitions);
  4470 
  4471 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4472 state; Note that presentation of goal states does not conform to
  4473 actual human-readable proof documents.  Please do not include goal
  4474 states into document output unless you really know what you are doing!
  4475 
  4476 * proper indentation of antiquoted output with proportional LaTeX
  4477 fonts;
  4478 
  4479 * no_document ML operator temporarily disables LaTeX document
  4480 generation;
  4481 
  4482 * isatool unsymbolize tunes sources for plain ASCII communication;
  4483 
  4484 
  4485 *** Isar ***
  4486 
  4487 * Pure: Isar now suffers initial goal statements to contain unbound
  4488 schematic variables (this does not conform to actual readable proof
  4489 documents, due to unpredictable outcome and non-compositional proof
  4490 checking); users who know what they are doing may use schematic goals
  4491 for Prolog-style synthesis of proven results;
  4492 
  4493 * Pure: assumption method (an implicit finishing) now handles actual
  4494 rules as well;
  4495 
  4496 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4497 initial goal, declare "that" only as Pure intro (only for single
  4498 steps); the "that" rule assumption may now be involved in implicit
  4499 finishing, thus ".." becomes a feasible for trivial obtains;
  4500 
  4501 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4502 instance proofs may be performed by "..";
  4503 
  4504 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4505 statements as well;
  4506 
  4507 * Pure: more robust selection of calculational rules;
  4508 
  4509 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4510 rule (as well as the assumption rule);
  4511 
  4512 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4513 lemmas, using the graph browser tool;
  4514 
  4515 * Pure: predict failure of "show" in interactive mode;
  4516 
  4517 * Pure: 'thms_containing' now takes actual terms as arguments;
  4518 
  4519 * HOL: improved method 'induct' --- now handles non-atomic goals
  4520 (potential INCOMPATIBILITY); tuned error handling;
  4521 
  4522 * HOL: cases and induct rules now provide explicit hints about the
  4523 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4524 any remaining facts are inserted into the goal verbatim;
  4525 
  4526 * HOL: local contexts (aka cases) may now contain term bindings as
  4527 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4528 the result to be shown in each case;
  4529 
  4530 * HOL: added 'recdef_tc' command;
  4531 
  4532 * isatool convert assists in eliminating legacy ML scripts;
  4533 
  4534 
  4535 *** HOL ***
  4536 
  4537 * HOL/Library: a collection of generic theories to be used together
  4538 with main HOL; the theory loader path already includes this directory
  4539 by default; the following existing theories have been moved here:
  4540 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4541 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4542 
  4543 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4544 modelling and verification task performed in Isabelle/HOL +
  4545 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4546 
  4547 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4548 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4549 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4550 'domain', this makes the theory consistent with mathematical
  4551 literature;
  4552 
  4553 * HOL basics: added overloaded operations "inverse" and "divide"
  4554 (infix "/"), syntax for generic "abs" operation, generic summation
  4555 operator \<Sum>;
  4556 
  4557 * HOL/typedef: simplified package, provide more useful rules (see also
  4558 HOL/subset.thy);
  4559 
  4560 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4561 now expressed as a proper nested rule (old-style tactic scripts may
  4562 require atomize_strip_tac to cope with non-atomic premises);
  4563 
  4564 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4565 to "split_conv" (old name still available for compatibility);
  4566 
  4567 * HOL: improved concrete syntax for strings (e.g. allows translation
  4568 rules with string literals);
  4569 
  4570 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4571  and Fleuriot's mechanization of analysis, including the transcendental
  4572  functions for the reals;
  4573 
  4574 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4575 
  4576 
  4577 *** CTT ***
  4578 
  4579 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4580 "lam" is displayed as TWO lambda-symbols
  4581 
  4582 * CTT: theory Main now available, containing everything (that is, Bool
  4583 and Arith);
  4584 
  4585 
  4586 *** General ***
  4587 
  4588 * Pure: the Simplifier has been implemented properly as a derived rule
  4589 outside of the actual kernel (at last!); the overall performance
  4590 penalty in practical applications is about 50%, while reliability of
  4591 the Isabelle inference kernel has been greatly improved;
  4592 
  4593 * print modes "brackets" and "no_brackets" control output of nested =>
  4594 (types) and ==> (props); the default behaviour is "brackets";
  4595 
  4596 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4597 as assumptions as well;
  4598 
  4599 * system: support Poly/ML 4.0;
  4600 
  4601 * system: isatool install handles KDE version 1 or 2;
  4602 
  4603 
  4604 
  4605 New in Isabelle99-1 (October 2000)
  4606 ----------------------------------
  4607 
  4608 *** Overview of INCOMPATIBILITIES ***
  4609 
  4610 * HOL: simplification of natural numbers is much changed; to partly
  4611 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4612 issue the following ML commands:
  4613 
  4614   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4615   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4616 
  4617 * HOL: simplification no longer dives into case-expressions; this is
  4618 controlled by "t.weak_case_cong" for each datatype t;
  4619 
  4620 * HOL: nat_less_induct renamed to less_induct;
  4621 
  4622 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4623 fixsome to patch .thy and .ML sources automatically;
  4624 
  4625   select_equality  -> some_equality
  4626   select_eq_Ex     -> some_eq_ex
  4627   selectI2EX       -> someI2_ex
  4628   selectI2         -> someI2
  4629   selectI          -> someI
  4630   select1_equality -> some1_equality
  4631   Eps_sym_eq       -> some_sym_eq_trivial
  4632   Eps_eq           -> some_eq_trivial
  4633 
  4634 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4635 
  4636 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4637 instead);
  4638 
  4639 * HOL: the recursion equations generated by 'recdef' are now called
  4640 f.simps instead of f.rules;
  4641 
  4642 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4643 
  4644 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4645 sometimes be needed;
  4646 
  4647 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4648 
  4649 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4650 
  4651 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4652 product is now "<*>" instead of "Times"; the lexicographic product is
  4653 now "<*lex*>" instead of "**";
  4654 
  4655 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4656 of main HOL, but was unused); better use HOL's datatype package;
  4657 
  4658 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4659 the old syntax may be recovered as follows:
  4660 
  4661   syntax (symbols)
  4662     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4663       (infixl "\\<oplus>" 100)
  4664 
  4665 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4666 
  4667 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4668 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4669 internally;
  4670 
  4671 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4672 changed from A/r to A//r;
  4673 
  4674 * ZF: new treatment of arithmetic (nat & int) may break some old
  4675 proofs;
  4676 
  4677 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4678 rulify -> rule_format, elimify -> elim_format, ...);
  4679 
  4680 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4681 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4682 should have to change intro!! to intro? only); replaced "delrule" by
  4683 "rule del";
  4684 
  4685 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4686 
  4687 * Provers: strengthened force_tac by using new first_best_tac;
  4688 
  4689 * LaTeX document preparation: several changes of isabelle.sty (see
  4690 lib/texinputs);
  4691 
  4692 
  4693 *** Document preparation ***
  4694 
  4695 * formal comments (text blocks etc.) in new-style theories may now
  4696 contain antiquotations of thm/prop/term/typ/text to be presented
  4697 according to latex print mode; concrete syntax is like this:
  4698 @{term[show_types] "f(x) = a + x"};
  4699 
  4700 * isatool mkdir provides easy setup of Isabelle session directories,
  4701 including proper document sources;
  4702 
  4703 * generated LaTeX sources are now deleted after successful run
  4704 (isatool document -c); may retain a copy somewhere else via -D option
  4705 of isatool usedir;
  4706 
  4707 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4708 style files, achieving self-contained LaTeX sources and simplifying
  4709 LaTeX debugging;
  4710 
  4711 * old-style theories now produce (crude) LaTeX output as well;
  4712 
  4713 * browser info session directories are now self-contained (may be put
  4714 on WWW server seperately); improved graphs of nested sessions; removed
  4715 graph for 'all sessions';
  4716 
  4717 * several improvements in isabelle style files; \isabellestyle{it}
  4718 produces fake math mode output; \isamarkupheader is now \section by
  4719 default; see lib/texinputs/isabelle.sty etc.;
  4720 
  4721 
  4722 *** Isar ***
  4723 
  4724 * Isar/Pure: local results and corresponding term bindings are now
  4725 subject to Hindley-Milner polymorphism (similar to ML); this
  4726 accommodates incremental type-inference very nicely;
  4727 
  4728 * Isar/Pure: new derived language element 'obtain' supports
  4729 generalized existence reasoning;
  4730 
  4731 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4732 support accumulation of results, without applying any rules yet;
  4733 useful to collect intermediate results without explicit name
  4734 references, and for use with transitivity rules with more than 2
  4735 premises;
  4736 
  4737 * Isar/Pure: scalable support for case-analysis type proofs: new
  4738 'case' language element refers to local contexts symbolically, as
  4739 produced by certain proof methods; internally, case names are attached
  4740 to theorems as "tags";
  4741 
  4742 * Isar/Pure: theory command 'hide' removes declarations from
  4743 class/type/const name spaces;
  4744 
  4745 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4746 indicate potential overloading;
  4747 
  4748 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4749 
  4750 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4751 "{a,b,c}" instead of {a,b,c};
  4752 
  4753 * Isar/Pure now provides its own version of intro/elim/dest
  4754 attributes; useful for building new logics, but beware of confusion
  4755 with the version in Provers/classical;
  4756 
  4757 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4758 case name 'antecedent';
  4759 
  4760 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4761 to the current context is now done automatically);
  4762 
  4763 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4764 for definining proof methods in ML;
  4765 
  4766 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4767 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4768 most cases, one should have to change intro!! to intro? only);
  4769 replaced "delrule" by "rule del";
  4770 
  4771 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4772 'symmetric' attribute (the latter supercedes [RS sym]);
  4773 
  4774 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4775 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4776 well (including splits);
  4777 
  4778 * Isar/Provers: Simplifier and Classical methods now support all kind
  4779 of modifiers used in the past, including 'cong', 'iff', etc.
  4780 
  4781 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4782 of Simplifier and Classical reasoner);
  4783 
  4784 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4785 now support named cases; major packages (inductive, datatype, primrec,
  4786 recdef) support case names and properly name parameters;
  4787 
  4788 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4789 monotonicity conditions are extracted to be proven at end of
  4790 calculations;
  4791 
  4792 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4793 method anyway;
  4794 
  4795 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4796 split_if split_if_asm; datatype package provides theorems foo.splits =
  4797 foo.split foo.split_asm for each datatype;
  4798 
  4799 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4800 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4801 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4802 use "(cases (simplified))" method in proper proof texts);
  4803 
  4804 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4805 
  4806 * Isar: names of theorems etc. may be natural numbers as well;
  4807 
  4808 * Isar: 'pr' command: optional arguments for goals_limit and
  4809 ProofContext.prems_limit; no longer prints theory contexts, but only
  4810 proof states;
  4811 
  4812 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4813 additional print modes to be specified; e.g. "pr(latex)" will print
  4814 proof state according to the Isabelle LaTeX style;
  4815 
  4816 * Isar: improved support for emulating tactic scripts, including proof
  4817 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4818 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4819 (for HOL datatypes);
  4820 
  4821 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4822 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4823 'proof method scripts' have to be in depth-first order;
  4824 
  4825 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4826 
  4827 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4828 should instead use individual commands for printing items
  4829 (print_commands, print_methods etc.);
  4830 
  4831 * Isar: added 'nothing' --- the empty list of theorems;
  4832 
  4833 
  4834 *** HOL ***
  4835 
  4836 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4837 corresponding virtual machine and a specification of its bytecode
  4838 verifier and a lightweight bytecode verifier, including proofs of
  4839 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4840 Cornelia Pusch (see also the homepage of project Bali at
  4841 http://isabelle.in.tum.de/Bali/);
  4842 
  4843 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4844 Clemens Ballarin;
  4845 
  4846 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4847 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4848 Rasmussen;
  4849 
  4850 * HOL/Lattice: fundamental concepts of lattice theory and order
  4851 structures, including duals, properties of bounds versus algebraic
  4852 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4853 Theorem for complete lattices etc.; may also serve as a demonstration
  4854 for abstract algebraic reasoning using axiomatic type classes, and
  4855 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4856 
  4857 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4858 von Oheimb;
  4859 
  4860 * HOL/IMPP: extension of IMP with local variables and mutually
  4861 recursive procedures, by David von Oheimb;
  4862 
  4863 * HOL/Lambda: converted into new-style theory and document;
  4864 
  4865 * HOL/ex/Multiquote: example of multiple nested quotations and
  4866 anti-quotations -- basically a generalized version of de-Bruijn
  4867 representation; very useful in avoiding lifting of operations;
  4868 
  4869 * HOL/record: added general record equality rule to simpset; fixed
  4870 select-update simplification procedure to handle extended records as
  4871 well; admit "r" as field name;
  4872 
  4873 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4874 other numeric types and also as the identity of groups, rings, etc.;
  4875 
  4876 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4877 Types nat and int belong to this axclass;
  4878 
  4879 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4880    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4881    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4882   two terms #m*u and #n*u are replaced by #(m+n)*u
  4883     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4884   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4885     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4886 
  4887 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4888 powerful prover for predicate logic but knows nothing of clasets; see
  4889 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4890 
  4891 * HOL: new version of "case_tac" subsumes both boolean case split and
  4892 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4893 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4894 
  4895 * HOL: simplification no longer dives into case-expressions: only the
  4896 selector expression is simplified, but not the remaining arms; to
  4897 enable full simplification of case-expressions for datatype t, you may
  4898 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4899 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4900 
  4901 * HOL/recdef: the recursion equations generated by 'recdef' for
  4902 function 'f' are now called f.simps instead of f.rules; if all
  4903 termination conditions are proved automatically, these simplification
  4904 rules are added to the simpset, as in primrec; rules may be named
  4905 individually as well, resulting in a separate list of theorems for
  4906 each equation;
  4907 
  4908 * HOL/While is a new theory that provides a while-combinator. It
  4909 permits the definition of tail-recursive functions without the
  4910 provision of a termination measure. The latter is necessary once the
  4911 invariant proof rule for while is applied.
  4912 
  4913 * HOL: new (overloaded) notation for the set of elements below/above
  4914 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4915 
  4916 * HOL: theorems impI, allI, ballI bound as "strip";
  4917 
  4918 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4919 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4920 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4921 
  4922 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4923 
  4924 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4925 main HOL, but was unused);
  4926 
  4927 * HOL: fewer consts declared as global (e.g. have to refer to
  4928 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4929 
  4930 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4931 in case of overlap with user translations (e.g. judgements over
  4932 tuples); (note that the underlying logical represenation is still
  4933 bogus);
  4934 
  4935 
  4936 *** ZF ***
  4937 
  4938 * ZF: simplification automatically cancels common terms in arithmetic
  4939 expressions over nat and int;
  4940 
  4941 * ZF: new treatment of nat to minimize type-checking: all operators
  4942 coerce their operands to a natural number using the function natify,
  4943 making the algebraic laws unconditional;
  4944 
  4945 * ZF: as above, for int: operators coerce their operands to an integer
  4946 using the function intify;
  4947 
  4948 * ZF: the integer library now contains many of the usual laws for the
  4949 orderings, including $<=, and monotonicity laws for $+ and $*;
  4950 
  4951 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4952 simplification;
  4953 
  4954 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4955 to the simplifier and classical reasoner simultaneously;
  4956 
  4957 
  4958 *** General ***
  4959 
  4960 * Provers: blast_tac now handles actual object-logic rules as
  4961 assumptions; note that auto_tac uses blast_tac internally as well;
  4962 
  4963 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4964 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4965 
  4966 * Provers: delrules now handles destruct rules as well (no longer need
  4967 explicit make_elim);
  4968 
  4969 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4970   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4971 use instead the strong form,
  4972   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4973 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4974 from destruct-rules;
  4975 
  4976 * Provers: Simplifier.easy_setup provides a fast path to basic
  4977 Simplifier setup for new object-logics;
  4978 
  4979 * Pure: AST translation rules no longer require constant head on LHS;
  4980 
  4981 * Pure: improved name spaces: ambiguous output is qualified; support
  4982 for hiding of names;
  4983 
  4984 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4985 XSYMBOL_HOME; no longer need to do manual configuration in most
  4986 situations;
  4987 
  4988 * system: compression of ML heaps images may now be controlled via -c
  4989 option of isabelle and isatool usedir (currently only observed by
  4990 Poly/ML);
  4991 
  4992 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4993 useful for remote X11);
  4994 
  4995 * system: provide TAGS file for Isabelle sources;
  4996 
  4997 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4998 order;
  4999 
  5000 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5001 timing flag supersedes proof_timing and Toplevel.trace;
  5002 
  5003 * ML: new combinators |>> and |>>> for incremental transformations
  5004 with secondary results (e.g. certain theory extensions):
  5005 
  5006 * ML: PureThy.add_defs gets additional argument to indicate potential
  5007 overloading (usually false);
  5008 
  5009 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5010 results;
  5011 
  5012 
  5013 
  5014 New in Isabelle99 (October 1999)
  5015 --------------------------------
  5016 
  5017 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5018 
  5019 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5020 are no longer simplified.  (This allows the simplifier to unfold recursive
  5021 functional programs.)  To restore the old behaviour, declare
  5022 
  5023     Delcongs [if_weak_cong];
  5024 
  5025 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5026 complement;
  5027 
  5028 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5029 
  5030 * HOL/datatype: mutual_induct_tac no longer exists --
  5031   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5032 
  5033 * HOL/typedef: fixed type inference for representing set; type
  5034 arguments now have to occur explicitly on the rhs as type constraints;
  5035 
  5036 * ZF: The con_defs part of an inductive definition may no longer refer
  5037 to constants declared in the same theory;
  5038 
  5039 * HOL, ZF: the function mk_cases, generated by the inductive
  5040 definition package, has lost an argument.  To simplify its result, it
  5041 uses the default simpset instead of a supplied list of theorems.
  5042 
  5043 * HOL/List: the constructors of type list are now Nil and Cons;
  5044 
  5045 * Simplifier: the type of the infix ML functions
  5046         setSSolver addSSolver setSolver addSolver
  5047 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5048 for packaging solvers. A solver is created via
  5049         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5050 where the string argument is only a comment.
  5051 
  5052 
  5053 *** Proof tools ***
  5054 
  5055 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5056 decision procedure for linear arithmetic. Currently it is used for
  5057 types `nat', `int', and `real' in HOL (see below); it can, should and
  5058 will be instantiated for other types and logics as well.
  5059 
  5060 * The simplifier now accepts rewrite rules with flexible heads, eg
  5061      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5062   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5063   matching.
  5064 
  5065 
  5066 *** General ***
  5067 
  5068 * New Isabelle/Isar subsystem provides an alternative to traditional
  5069 tactical theorem proving; together with the ProofGeneral/isar user
  5070 interface it offers an interactive environment for developing human
  5071 readable proof documents (Isar == Intelligible semi-automated
  5072 reasoning); for further information see isatool doc isar-ref,
  5073 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5074 
  5075 * improved and simplified presentation of theories: better HTML markup
  5076 (including colors), graph views in several sizes; isatool usedir now
  5077 provides a proper interface for user theories (via -P option); actual
  5078 document preparation based on (PDF)LaTeX is available as well (for
  5079 new-style theories only); see isatool doc system for more information;
  5080 
  5081 * native support for Proof General, both for classic Isabelle and
  5082 Isabelle/Isar;
  5083 
  5084 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5085 using the graph browser tool;
  5086 
  5087 * Isabelle manuals now also available as PDF;
  5088 
  5089 * theory loader rewritten from scratch (may not be fully
  5090 bug-compatible); old loadpath variable has been replaced by show_path,
  5091 add_path, del_path, reset_path functions; new operations such as
  5092 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5093 isatool doc ref);
  5094 
  5095 * improved isatool install: option -k creates KDE application icon,
  5096 option -p DIR installs standalone binaries;
  5097 
  5098 * added ML_PLATFORM setting (useful for cross-platform installations);
  5099 more robust handling of platform specific ML images for SML/NJ;
  5100 
  5101 * the settings environment is now statically scoped, i.e. it is never
  5102 created again in sub-processes invoked from isabelle, isatool, or
  5103 Isabelle;
  5104 
  5105 * path element specification '~~' refers to '$ISABELLE_HOME';
  5106 
  5107 * in locales, the "assumes" and "defines" parts may be omitted if
  5108 empty;
  5109 
  5110 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5111 long arrows);
  5112 
  5113 * new print_mode "HTML";
  5114 
  5115 * new flag show_tags controls display of tags of theorems (which are
  5116 basically just comments that may be attached by some tools);
  5117 
  5118 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5119 mode and goal output format:
  5120 
  5121 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5122 244c244
  5123 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5124 ---
  5125 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5126 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5127 181c181
  5128 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5129 ---
  5130 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5131 
  5132 * function bind_thms stores lists of theorems (cf. bind_thm);
  5133 
  5134 * new shorthand tactics ftac, eatac, datac, fatac;
  5135 
  5136 * qed (and friends) now accept "" as result name; in that case the
  5137 theorem is not stored, but proper checks and presentation of the
  5138 result still apply;
  5139 
  5140 * theorem database now also indexes constants "Trueprop", "all",
  5141 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5142 
  5143 
  5144 *** HOL ***
  5145 
  5146 ** HOL arithmetic **
  5147 
  5148 * There are now decision procedures for linear arithmetic over nat and
  5149 int:
  5150 
  5151 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5152 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5153 are treated as atomic; subformulae not involving type `nat' or `int'
  5154 are ignored; quantified subformulae are ignored unless they are
  5155 positive universal or negative existential. The tactic has to be
  5156 invoked by hand and can be a little bit slow. In particular, the
  5157 running time is exponential in the number of occurrences of `min' and
  5158 `max', and `-' on `nat'.
  5159 
  5160 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5161 (negated) (in)equalities among the premises and the conclusion into
  5162 account (i.e. no compound formulae) and does not know about `min' and
  5163 `max', and `-' on `nat'. It is fast and is used automatically by the
  5164 simplifier.
  5165 
  5166 NB: At the moment, these decision procedures do not cope with mixed
  5167 nat/int formulae where the two parts interact, such as `m < n ==>
  5168 int(m) < int(n)'.
  5169 
  5170 * HOL/Numeral provides a generic theory of numerals (encoded
  5171 efficiently as bit strings); setup for types nat/int/real is in place;
  5172 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5173 int, existing theories and proof scripts may require a few additional
  5174 type constraints;
  5175 
  5176 * integer division and remainder can now be performed on constant
  5177 arguments;
  5178 
  5179 * many properties of integer multiplication, division and remainder
  5180 are now available;
  5181 
  5182 * An interface to the Stanford Validity Checker (SVC) is available through the
  5183 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5184 are proved automatically.  SVC must be installed separately, and its results
  5185 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5186 invocation of the underlying oracle).  For SVC see
  5187   http://verify.stanford.edu/SVC
  5188 
  5189 * IsaMakefile: the HOL-Real target now builds an actual image;
  5190 
  5191 
  5192 ** HOL misc **
  5193 
  5194 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5195 (in Isabelle/Isar) -- by Gertrud Bauer;
  5196 
  5197 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5198 analysis for assembly languages with subtypes;
  5199 
  5200 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5201 -- avoids syntactic ambiguities and treats state, transition, and
  5202 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5203 changed syntax and (many) tactics;
  5204 
  5205 * HOL/inductive: Now also handles more general introduction rules such
  5206   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5207   theorems are now maintained within the theory (maintained via the
  5208   "mono" attribute);
  5209 
  5210 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5211   (using function types) such as
  5212 
  5213   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5214 
  5215 * HOL/record: record_simproc (part of the default simpset) takes care
  5216 of selectors applied to updated records; record_split_tac is no longer
  5217 part of the default claset; update_defs may now be removed from the
  5218 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5219 
  5220   claset_ref () := claset() addSWrapper record_split_wrapper;
  5221   Delsimprocs [record_simproc]
  5222 
  5223 * HOL/typedef: fixed type inference for representing set; type
  5224 arguments now have to occur explicitly on the rhs as type constraints;
  5225 
  5226 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5227 names rather than an ML expression;
  5228 
  5229 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5230 supplied later.  Program schemes can be defined, such as
  5231     "While B C s = (if B s then While B C (C s) else s)"
  5232 where the well-founded relation can be chosen after B and C have been given.
  5233 
  5234 * HOL/List: the constructors of type list are now Nil and Cons;
  5235 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5236 course, ML tools referring to List.list.op # etc. have to be adapted;
  5237 
  5238 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5239 disabled by default; run isabelle with option -m HOL to get back to
  5240 the original Gordon/HOL-style output;
  5241 
  5242 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5243 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5244 
  5245 * HOL basic syntax simplified (more orthogonal): all variants of
  5246 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5247 Eps operator is provided as well: "SOME x. P[x]";
  5248 
  5249 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5250 
  5251 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5252 thus available for user theories;
  5253 
  5254 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5255 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5256 time;
  5257 
  5258 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5259 several times and then mp;
  5260 
  5261 
  5262 *** LK ***
  5263 
  5264 * the notation <<...>> is now available as a notation for sequences of
  5265 formulas;
  5266 
  5267 * the simplifier is now installed
  5268 
  5269 * the axiom system has been generalized (thanks to Soren Heilmann)
  5270 
  5271 * the classical reasoner now has a default rule database
  5272 
  5273 
  5274 *** ZF ***
  5275 
  5276 * new primrec section allows primitive recursive functions to be given
  5277 directly (as in HOL) over datatypes and the natural numbers;
  5278 
  5279 * new tactics induct_tac and exhaust_tac for induction (or case
  5280 analysis) over datatypes and the natural numbers;
  5281 
  5282 * the datatype declaration of type T now defines the recursor T_rec;
  5283 
  5284 * simplification automatically does freeness reasoning for datatype
  5285 constructors;
  5286 
  5287 * automatic type-inference, with AddTCs command to insert new
  5288 type-checking rules;
  5289 
  5290 * datatype introduction rules are now added as Safe Introduction rules
  5291 to the claset;
  5292 
  5293 * the syntax "if P then x else y" is now available in addition to
  5294 if(P,x,y);
  5295 
  5296 
  5297 *** Internal programming interfaces ***
  5298 
  5299 * tuned simplifier trace output; new flag debug_simp;
  5300 
  5301 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5302 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5303 
  5304 * AxClass.axclass_tac lost the theory argument;
  5305 
  5306 * tuned current_goals_markers semantics: begin / end goal avoids
  5307 printing empty lines;
  5308 
  5309 * removed prs and prs_fn hook, which was broken because it did not
  5310 include \n in its semantics, forcing writeln to add one
  5311 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5312 string -> unit if you really want to output text without newline;
  5313 
  5314 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5315 plain output, interface builders may have to enable 'isabelle_font'
  5316 mode to get Isabelle font glyphs as before;
  5317 
  5318 * refined token_translation interface; INCOMPATIBILITY: output length
  5319 now of type real instead of int;
  5320 
  5321 * theory loader actions may be traced via new ThyInfo.add_hook
  5322 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5323 your own database of information attached to *whole* theories -- as
  5324 opposed to intra-theory data slots offered via TheoryDataFun;
  5325 
  5326 * proper handling of dangling sort hypotheses (at last!);
  5327 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5328 extra sort hypotheses that can be witnessed from the type signature;
  5329 the force_strip_shyps flag is gone, any remaining shyps are simply
  5330 left in the theorem (with a warning issued by strip_shyps_warning);
  5331 
  5332 
  5333 
  5334 New in Isabelle98-1 (October 1998)
  5335 ----------------------------------
  5336 
  5337 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5338 
  5339 * several changes of automated proof tools;
  5340 
  5341 * HOL: major changes to the inductive and datatype packages, including
  5342 some minor incompatibilities of theory syntax;
  5343 
  5344 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5345 called `inj_on';
  5346 
  5347 * HOL: removed duplicate thms in Arith:
  5348   less_imp_add_less  should be replaced by  trans_less_add1
  5349   le_imp_add_le      should be replaced by  trans_le_add1
  5350 
  5351 * HOL: unary minus is now overloaded (new type constraints may be
  5352 required);
  5353 
  5354 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5355 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5356 now taken as an integer constant.
  5357 
  5358 * Pure: ML function 'theory_of' renamed to 'theory';
  5359 
  5360 
  5361 *** Proof tools ***
  5362 
  5363 * Simplifier:
  5364   1. Asm_full_simp_tac is now more aggressive.
  5365      1. It will sometimes reorient premises if that increases their power to
  5366         simplify.
  5367      2. It does no longer proceed strictly from left to right but may also
  5368         rotate premises to achieve further simplification.
  5369      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5370      old Asm_full_simp_tac in that it does not rotate premises.
  5371   2. The simplifier now knows a little bit about nat-arithmetic.
  5372 
  5373 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5374 allows for selected deletion of wrappers, by introduction of names for
  5375 wrapper functionals.  This implies that addbefore, addSbefore,
  5376 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5377 and that adding two tactics with the same name overwrites the first
  5378 one (emitting a warning).
  5379   type wrapper = (int -> tactic) -> (int -> tactic)
  5380   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5381   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5382   delWrapper, delSWrapper: claset *  string            -> claset
  5383   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5384 
  5385 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5386 semantics; addbefore now affects only the unsafe part of step_tac
  5387 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5388 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5389 by Force_tac;
  5390 
  5391 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5392 compWrapper; added safe wrapper (and access functions for it);
  5393 
  5394 * HOL/split_all_tac is now much faster and fails if there is nothing
  5395 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5396 and the names of the automatically generated variables have changed.
  5397 split_all_tac has moved within claset() from unsafe wrappers to safe
  5398 wrappers, which means that !!-bound variables are split much more
  5399 aggressively, and safe_tac and clarify_tac now split such variables.
  5400 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5401 Note: the same holds for record_split_tac, which does the job of
  5402 split_all_tac for record fields.
  5403 
  5404 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5405 permanently to the default simpset using Addsplits just like
  5406 Addsimps. They can be removed via Delsplits just like
  5407 Delsimps. Lower-case versions are also available.
  5408 
  5409 * HOL/Simplifier: The rule split_if is now part of the default
  5410 simpset. This means that the simplifier will eliminate all occurrences
  5411 of if-then-else in the conclusion of a goal. To prevent this, you can
  5412 either remove split_if completely from the default simpset by
  5413 `Delsplits [split_if]' or remove it in a specific call of the
  5414 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5415 other case splitting rules to/from the default simpset: every datatype
  5416 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5417 t is the name of the datatype).
  5418 
  5419 * Classical reasoner / Simplifier combination: new force_tac (and
  5420 derivatives Force_tac, force) combines rewriting and classical
  5421 reasoning (and whatever other tools) similarly to auto_tac, but is
  5422 aimed to solve the given subgoal completely.
  5423 
  5424 
  5425 *** General ***
  5426 
  5427 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5428 and `goalw': the theory is no longer needed as an explicit argument -
  5429 the current theory context is used; assumptions are no longer returned
  5430 at the ML-level unless one of them starts with ==> or !!; it is
  5431 recommended to convert to these new commands using isatool fixgoal
  5432 (backup your sources first!);
  5433 
  5434 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5435 the current theory context, and 'theory' to lookup stored theories;
  5436 
  5437 * new theory section 'locale' for declaring constants, assumptions and
  5438 definitions that have local scope;
  5439 
  5440 * new theory section 'nonterminals' for purely syntactic types;
  5441 
  5442 * new theory section 'setup' for generic ML setup functions
  5443 (e.g. package initialization);
  5444 
  5445 * the distribution now includes Isabelle icons: see
  5446 lib/logo/isabelle-{small,tiny}.xpm;
  5447 
  5448 * isatool install - install binaries with absolute references to
  5449 ISABELLE_HOME/bin;
  5450 
  5451 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5452 
  5453 * print mode 'emacs' reserved for Isamode;
  5454 
  5455 * support multiple print (ast) translations per constant name;
  5456 
  5457 * theorems involving oracles are now printed with a suffixed [!];
  5458 
  5459 
  5460 *** HOL ***
  5461 
  5462 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5463 
  5464 * HOL/inductive package reorganized and improved: now supports mutual
  5465 definitions such as
  5466 
  5467   inductive EVEN ODD
  5468     intrs
  5469       null "0 : EVEN"
  5470       oddI "n : EVEN ==> Suc n : ODD"
  5471       evenI "n : ODD ==> Suc n : EVEN"
  5472 
  5473 new theorem list "elims" contains an elimination rule for each of the
  5474 recursive sets; inductive definitions now handle disjunctive premises
  5475 correctly (also ZF);
  5476 
  5477 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5478 "mutual_induct" no longer exists - the induction rule is always
  5479 contained in "induct";
  5480 
  5481 
  5482 * HOL/datatype package re-implemented and greatly improved: now
  5483 supports mutually recursive datatypes such as
  5484 
  5485   datatype
  5486     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5487             | SUM ('a aexp) ('a aexp)
  5488             | DIFF ('a aexp) ('a aexp)
  5489             | NUM 'a
  5490   and
  5491     'a bexp = LESS ('a aexp) ('a aexp)
  5492             | AND ('a bexp) ('a bexp)
  5493             | OR ('a bexp) ('a bexp)
  5494 
  5495 as well as indirectly recursive datatypes such as
  5496 
  5497   datatype
  5498     ('a, 'b) term = Var 'a
  5499                   | App 'b ((('a, 'b) term) list)
  5500 
  5501 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5502 induction on mutually / indirectly recursive datatypes.
  5503 
  5504 Primrec equations are now stored in theory and can be accessed via
  5505 <function_name>.simps.
  5506 
  5507 INCOMPATIBILITIES:
  5508 
  5509   - Theories using datatypes must now have theory Datatype as an
  5510     ancestor.
  5511   - The specific <typename>.induct_tac no longer exists - use the
  5512     generic induct_tac instead.
  5513   - natE has been renamed to nat.exhaust - use exhaust_tac
  5514     instead of res_inst_tac ... natE. Note that the variable
  5515     names in nat.exhaust differ from the names in natE, this
  5516     may cause some "fragile" proofs to fail.
  5517   - The theorems split_<typename>_case and split_<typename>_case_asm
  5518     have been renamed to <typename>.split and <typename>.split_asm.
  5519   - Since default sorts of type variables are now handled correctly,
  5520     some datatype definitions may have to be annotated with explicit
  5521     sort constraints.
  5522   - Primrec definitions no longer require function name and type
  5523     of recursive argument.
  5524 
  5525 Consider using isatool fixdatatype to adapt your theories and proof
  5526 scripts to the new package (backup your sources first!).
  5527 
  5528 
  5529 * HOL/record package: considerably improved implementation; now
  5530 includes concrete syntax for record types, terms, updates; theorems
  5531 for surjective pairing and splitting !!-bound record variables; proof
  5532 support is as follows:
  5533 
  5534   1) standard conversions (selectors or updates applied to record
  5535 constructor terms) are part of the standard simpset;
  5536 
  5537   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5538 made part of standard simpset and claset via addIffs;
  5539 
  5540   3) a tactic for record field splitting (record_split_tac) is part of
  5541 the standard claset (addSWrapper);
  5542 
  5543 To get a better idea about these rules you may retrieve them via
  5544 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5545 the name of your record type.
  5546 
  5547 The split tactic 3) conceptually simplifies by the following rule:
  5548 
  5549   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5550 
  5551 Thus any record variable that is bound by meta-all will automatically
  5552 blow up into some record constructor term, consequently the
  5553 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5554 solve record problems automatically.
  5555 
  5556 
  5557 * reorganized the main HOL image: HOL/Integ and String loaded by
  5558 default; theory Main includes everything;
  5559 
  5560 * automatic simplification of integer sums and comparisons, using cancellation;
  5561 
  5562 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5563 
  5564 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5565 
  5566 * many new identities for unions, intersections, set difference, etc.;
  5567 
  5568 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5569 called split_if, split_split, split_sum_case and split_nat_case (to go
  5570 with add/delsplits);
  5571 
  5572 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5573 (?x::unit) = (); this is made part of the default simpset, which COULD
  5574 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5575 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5576 unit_abs_eta_conv is added in order to counter the effect of
  5577 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5578 %u.f();
  5579 
  5580 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5581 makes more sense);
  5582 
  5583 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5584   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5585   disjointness reasoning but breaking a few old proofs.
  5586 
  5587 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5588 to 'converse' from 'inverse' (for compatibility with ZF and some
  5589 literature);
  5590 
  5591 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5592 the well-founded relation;
  5593 
  5594 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5595     Compl A.  The "Compl" syntax remains available as input syntax for this
  5596     release ONLY.
  5597 
  5598 * HOL/Update: new theory of function updates:
  5599     f(a:=b) == %x. if x=a then b else f x
  5600 may also be iterated as in f(a:=b,c:=d,...);
  5601 
  5602 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5603 
  5604 * HOL/List:
  5605   - new function list_update written xs[i:=v] that updates the i-th
  5606     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5607   - new function `upt' written [i..j(] which generates the list
  5608     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5609     bound write [i..j], which is a shorthand for [i..j+1(].
  5610   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5611 
  5612 * HOL/Arith:
  5613   - removed 'pred' (predecessor) function;
  5614   - generalized some theorems about n-1;
  5615   - many new laws about "div" and "mod";
  5616   - new laws about greatest common divisors (see theory ex/Primes);
  5617 
  5618 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5619 instead of "inverse";
  5620 
  5621 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5622   of the multiset ordering;
  5623 
  5624 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5625   (not included by default);
  5626 
  5627 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5628 
  5629 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5630   programs, i.e. different program variables may have different types.
  5631 
  5632 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5633   [previously, this check worked only if the rewrite rule was unconditional]
  5634   Now rew can involve either definitions or equalities (either == or =).
  5635 
  5636 
  5637 *** ZF ***
  5638 
  5639 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5640   only the theorems proved on ZF.ML;
  5641 
  5642 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5643   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5644   disjointness reasoning but breaking a few old proofs.
  5645 
  5646 * ZF/Update: new theory of function updates
  5647     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5648   may also be iterated as in f(a:=b,c:=d,...);
  5649 
  5650 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5651 
  5652 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5653   [previously, this check worked only if the rewrite rule was unconditional]
  5654   Now rew can involve either definitions or equalities (either == or =).
  5655 
  5656 * case_tac provided for compatibility with HOL
  5657     (like the old excluded_middle_tac, but with subgoals swapped)
  5658 
  5659 
  5660 *** Internal programming interfaces ***
  5661 
  5662 * Pure: several new basic modules made available for general use, see
  5663 also src/Pure/README;
  5664 
  5665 * improved the theory data mechanism to support encapsulation (data
  5666 kind name replaced by private Object.kind, acting as authorization
  5667 key); new type-safe user interface via functor TheoryDataFun; generic
  5668 print_data function becomes basically useless;
  5669 
  5670 * removed global_names compatibility flag -- all theory declarations
  5671 are qualified by default;
  5672 
  5673 * module Pure/Syntax now offers quote / antiquote translation
  5674 functions (useful for Hoare logic etc. with implicit dependencies);
  5675 see HOL/ex/Antiquote for an example use;
  5676 
  5677 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5678 cterm -> thm;
  5679 
  5680 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5681 subgoal;
  5682 
  5683 * Display.print_goals function moved to Locale.print_goals;
  5684 
  5685 * standard print function for goals supports current_goals_markers
  5686 variable for marking begin of proof, end of proof, start of goal; the
  5687 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5688 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5689 for example;
  5690 
  5691 
  5692 
  5693 New in Isabelle98 (January 1998)
  5694 --------------------------------
  5695 
  5696 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5697 
  5698 * changed lexical syntax of terms / types: dots made part of long
  5699 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5700 
  5701 * simpset (and claset) reference variable replaced by functions
  5702 simpset / simpset_ref;
  5703 
  5704 * no longer supports theory aliases (via merge) and non-trivial
  5705 implicit merge of thms' signatures;
  5706 
  5707 * most internal names of constants changed due to qualified names;
  5708 
  5709 * changed Pure/Sequence interface (see Pure/seq.ML);
  5710 
  5711 
  5712 *** General Changes ***
  5713 
  5714 * hierachically structured name spaces (for consts, types, axms, thms
  5715 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5716 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5717 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5718 long_names for fully qualified output names; NOTE: ML programs
  5719 (special tactics, packages etc.) referring to internal names may have
  5720 to be adapted to cope with fully qualified names; in case of severe
  5721 backward campatibility problems try setting 'global_names' at compile
  5722 time to have enrything declared within a flat name space; one may also
  5723 fine tune name declarations in theories via the 'global' and 'local'
  5724 section;
  5725 
  5726 * reimplemented the implicit simpset and claset using the new anytype
  5727 data filed in signatures; references simpset:simpset ref etc. are
  5728 replaced by functions simpset:unit->simpset and
  5729 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5730 to patch your ML files accordingly;
  5731 
  5732 * HTML output now includes theory graph data for display with Java
  5733 applet or isatool browser; data generated automatically via isatool
  5734 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5735 
  5736 * defs may now be conditional; improved rewrite_goals_tac to handle
  5737 conditional equations;
  5738 
  5739 * defs now admits additional type arguments, using TYPE('a) syntax;
  5740 
  5741 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5742 creates a new theory node; implicit merge of thms' signatures is
  5743 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5744 transfer:theory->thm->thm in (rare) cases;
  5745 
  5746 * improved handling of draft signatures / theories; draft thms (and
  5747 ctyps, cterms) are automatically promoted to real ones;
  5748 
  5749 * slightly changed interfaces for oracles: admit many per theory, named
  5750 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5751 
  5752 * print_goals: optional output of const types (set show_consts and
  5753 show_types);
  5754 
  5755 * improved output of warnings (###) and errors (***);
  5756 
  5757 * subgoal_tac displays a warning if the new subgoal has type variables;
  5758 
  5759 * removed old README and Makefiles;
  5760 
  5761 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5762 
  5763 * removed obsolete init_pps and init_database;
  5764 
  5765 * deleted the obsolete tactical STATE, which was declared by
  5766     fun STATE tacfun st = tacfun st st;
  5767 
  5768 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5769 (which abbreviates $HOME);
  5770 
  5771 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5772 use isatool fixseq to adapt your ML programs (this works for fully
  5773 qualified references to the Sequence structure only!);
  5774 
  5775 * use_thy no longer requires writable current directory; it always
  5776 reloads .ML *and* .thy file, if either one is out of date;
  5777 
  5778 
  5779 *** Classical Reasoner ***
  5780 
  5781 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5782 tactics that use classical reasoning to simplify a subgoal without
  5783 splitting it into several subgoals;
  5784 
  5785 * Safe_tac: like safe_tac but uses the default claset;
  5786 
  5787 
  5788 *** Simplifier ***
  5789 
  5790 * added simplification meta rules:
  5791     (asm_)(full_)simplify: simpset -> thm -> thm;
  5792 
  5793 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5794 logics (again);
  5795 
  5796 * added prems argument to simplification procedures;
  5797 
  5798 * HOL, FOL, ZF: added infix function `addsplits':
  5799   instead of `<simpset> setloop (split_tac <thms>)'
  5800   you can simply write `<simpset> addsplits <thms>'
  5801 
  5802 
  5803 *** Syntax ***
  5804 
  5805 * TYPE('a) syntax for type reflection terms;
  5806 
  5807 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5808 
  5809 * pretty printer: changed order of mixfix annotation preference (again!);
  5810 
  5811 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5812 
  5813 
  5814 *** HOL ***
  5815 
  5816 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5817   with `addloop' of the simplifier to faciliate case splitting in premises.
  5818 
  5819 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5820 
  5821 * HOL/Auth: new protocol proofs including some for the Internet
  5822   protocol TLS;
  5823 
  5824 * HOL/Map: new theory of `maps' a la VDM;
  5825 
  5826 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5827 cancelling out common nat summands from =, <, <= (in)equalities, or
  5828 differences; simplification procedures nat_cancel_factor for
  5829 cancelling common factor from =, <, <= (in)equalities over natural
  5830 sums; nat_cancel contains both kinds of procedures, it is installed by
  5831 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5832 
  5833 * HOL/simplifier: terms of the form
  5834   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5835   are rewritten to
  5836   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5837   and those of the form
  5838   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5839   are rewritten to
  5840   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5841 
  5842 * HOL/datatype
  5843   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5844 
  5845   P(t_case f1 ... fn x) =
  5846      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5847         ...
  5848        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5849      )
  5850 
  5851   and a theorem `split_t_case_asm' of the form
  5852 
  5853   P(t_case f1 ... fn x) =
  5854     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5855         ...
  5856        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5857      )
  5858   which can be added to a simpset via `addsplits'. The existing theorems
  5859   expand_list_case and expand_option_case have been renamed to
  5860   split_list_case and split_option_case.
  5861 
  5862 * HOL/Arithmetic:
  5863   - `pred n' is automatically converted to `n-1'.
  5864     Users are strongly encouraged not to use `pred' any longer,
  5865     because it will disappear altogether at some point.
  5866   - Users are strongly encouraged to write "0 < n" rather than
  5867     "n ~= 0". Theorems and proof tools have been modified towards this
  5868     `standard'.
  5869 
  5870 * HOL/Lists:
  5871   the function "set_of_list" has been renamed "set" (and its theorems too);
  5872   the function "nth" now takes its arguments in the reverse order and
  5873   has acquired the infix notation "!" as in "xs!n".
  5874 
  5875 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5876 
  5877 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5878   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5879 
  5880 * HOL/record: extensible records with schematic structural subtyping
  5881 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5882 still lacks various theorems and concrete record syntax;
  5883 
  5884 
  5885 *** HOLCF ***
  5886 
  5887 * removed "axioms" and "generated by" sections;
  5888 
  5889 * replaced "ops" section by extended "consts" section, which is capable of
  5890   handling the continuous function space "->" directly;
  5891 
  5892 * domain package:
  5893   . proves theorems immediately and stores them in the theory,
  5894   . creates hierachical name space,
  5895   . now uses normal mixfix annotations (instead of cinfix...),
  5896   . minor changes to some names and values (for consistency),
  5897   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5898   . separator between mutual domain defs: changed "," to "and",
  5899   . improved handling of sort constraints;  now they have to
  5900     appear on the left-hand side of the equations only;
  5901 
  5902 * fixed LAM <x,y,zs>.b syntax;
  5903 
  5904 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5905 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5906 
  5907 
  5908 *** FOL and ZF ***
  5909 
  5910 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5911   with `addloop' of the simplifier to faciliate case splitting in premises.
  5912 
  5913 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5914 in HOL, they strip ALL and --> from proved theorems;
  5915 
  5916 
  5917 
  5918 New in Isabelle94-8 (May 1997)
  5919 ------------------------------
  5920 
  5921 *** General Changes ***
  5922 
  5923 * new utilities to build / run / maintain Isabelle etc. (in parts
  5924 still somewhat experimental); old Makefiles etc. still functional;
  5925 
  5926 * new 'Isabelle System Manual';
  5927 
  5928 * INSTALL text, together with ./configure and ./build scripts;
  5929 
  5930 * reimplemented type inference for greater efficiency, better error
  5931 messages and clean internal interface;
  5932 
  5933 * prlim command for dealing with lots of subgoals (an easier way of
  5934 setting goals_limit);
  5935 
  5936 
  5937 *** Syntax ***
  5938 
  5939 * supports alternative (named) syntax tables (parser and pretty
  5940 printer); internal interface is provided by add_modesyntax(_i);
  5941 
  5942 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5943 be used in conjunction with the Isabelle symbol font; uses the
  5944 "symbols" syntax table;
  5945 
  5946 * added token_translation interface (may translate name tokens in
  5947 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5948 the current print_mode); IMPORTANT: user print translation functions
  5949 are responsible for marking newly introduced bounds
  5950 (Syntax.mark_boundT);
  5951 
  5952 * token translations for modes "xterm" and "xterm_color" that display
  5953 names in bold, underline etc. or colors (which requires a color
  5954 version of xterm);
  5955 
  5956 * infixes may now be declared with names independent of their syntax;
  5957 
  5958 * added typed_print_translation (like print_translation, but may
  5959 access type of constant);
  5960 
  5961 
  5962 *** Classical Reasoner ***
  5963 
  5964 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5965 some limitations.  Blast_tac...
  5966   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5967   + ignores elimination rules that don't have the correct format
  5968         (the conclusion MUST be a formula variable)
  5969   + ignores types, which can make HOL proofs fail
  5970   + rules must not require higher-order unification, e.g. apply_type in ZF
  5971     [message "Function Var's argument not a bound variable" relates to this]
  5972   + its proof strategy is more general but can actually be slower
  5973 
  5974 * substitution with equality assumptions no longer permutes other
  5975 assumptions;
  5976 
  5977 * minor changes in semantics of addafter (now called addaltern); renamed
  5978 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5979 (and access functions for it);
  5980 
  5981 * improved combination of classical reasoner and simplifier:
  5982   + functions for handling clasimpsets
  5983   + improvement of addss: now the simplifier is called _after_ the
  5984     safe steps.
  5985   + safe variant of addss called addSss: uses safe simplifications
  5986     _during_ the safe steps. It is more complete as it allows multiple
  5987     instantiations of unknowns (e.g. with slow_tac).
  5988 
  5989 *** Simplifier ***
  5990 
  5991 * added interface for simplification procedures (functions that
  5992 produce *proven* rewrite rules on the fly, depending on current
  5993 redex);
  5994 
  5995 * ordering on terms as parameter (used for ordered rewriting);
  5996 
  5997 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5998 
  5999 * the solver is now split into a safe and an unsafe part.
  6000 This should be invisible for the normal user, except that the
  6001 functions setsolver and addsolver have been renamed to setSolver and
  6002 addSolver; added safe_asm_full_simp_tac;
  6003 
  6004 
  6005 *** HOL ***
  6006 
  6007 * a generic induction tactic `induct_tac' which works for all datatypes and
  6008 also for type `nat';
  6009 
  6010 * a generic case distinction tactic `exhaust_tac' which works for all
  6011 datatypes and also for type `nat';
  6012 
  6013 * each datatype comes with a function `size';
  6014 
  6015 * patterns in case expressions allow tuple patterns as arguments to
  6016 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6017 
  6018 * primrec now also works with type nat;
  6019 
  6020 * recdef: a new declaration form, allows general recursive functions to be
  6021 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6022 
  6023 * the constant for negation has been renamed from "not" to "Not" to
  6024 harmonize with FOL, ZF, LK, etc.;
  6025 
  6026 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6027 infinite lists;
  6028 
  6029 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6030 
  6031 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6032 problems in commutative rings, using axiomatic type classes for + and *;
  6033 
  6034 * more examples in HOL/MiniML and HOL/Auth;
  6035 
  6036 * more default rewrite rules for quantifiers, union/intersection;
  6037 
  6038 * a new constant `arbitrary == @x.False';
  6039 
  6040 * HOLCF/IOA replaces old HOL/IOA;
  6041 
  6042 * HOLCF changes: derived all rules and arities
  6043   + axiomatic type classes instead of classes
  6044   + typedef instead of faking type definitions
  6045   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6046   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6047   + eliminated the types void, one, tr
  6048   + use unit lift and bool lift (with translations) instead of one and tr
  6049   + eliminated blift from Lift3.thy (use Def instead of blift)
  6050   all eliminated rules are derived as theorems --> no visible changes ;
  6051 
  6052 
  6053 *** ZF ***
  6054 
  6055 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6056 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6057 as ZF_cs addSIs [equalityI];
  6058 
  6059 
  6060 
  6061 New in Isabelle94-7 (November 96)
  6062 ---------------------------------
  6063 
  6064 * allowing negative levels (as offsets) in prlev and choplev;
  6065 
  6066 * super-linear speedup for large simplifications;
  6067 
  6068 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6069 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6070 FAIL); can suppress it using the command Delsimps (ex_simps @
  6071 all_simps); De Morgan laws are also now included, by default;
  6072 
  6073 * improved printing of ==>  :  ~:
  6074 
  6075 * new object-logic "Sequents" adds linear logic, while replacing LK
  6076 and Modal (thanks to Sara Kalvala);
  6077 
  6078 * HOL/Auth: correctness proofs for authentication protocols;
  6079 
  6080 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6081 examples on HOL/Auth);
  6082 
  6083 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6084 the rewriter and classical reasoner simultaneously;
  6085 
  6086 * function uresult no longer returns theorems in "standard" format;
  6087 regain previous version by: val uresult = standard o uresult;
  6088 
  6089 
  6090 
  6091 New in Isabelle94-6
  6092 -------------------
  6093 
  6094 * oracles -- these establish an interface between Isabelle and trusted
  6095 external reasoners, which may deliver results as theorems;
  6096 
  6097 * proof objects (in particular record all uses of oracles);
  6098 
  6099 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6100 
  6101 * "constdefs" section in theory files;
  6102 
  6103 * "primrec" section (HOL) no longer requires names;
  6104 
  6105 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6106 
  6107 
  6108 
  6109 New in Isabelle94-5
  6110 -------------------
  6111 
  6112 * reduced space requirements;
  6113 
  6114 * automatic HTML generation from theories;
  6115 
  6116 * theory files no longer require "..." (quotes) around most types;
  6117 
  6118 * new examples, including two proofs of the Church-Rosser theorem;
  6119 
  6120 * non-curried (1994) version of HOL is no longer distributed;
  6121 
  6122 
  6123 
  6124 New in Isabelle94-4
  6125 -------------------
  6126 
  6127 * greatly reduced space requirements;
  6128 
  6129 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6130 
  6131 * searchable theorem database (see the section "Retrieving theorems" on
  6132 page 8 of the Reference Manual);
  6133 
  6134 * new examples, including Grabczewski's monumental case study of the
  6135 Axiom of Choice;
  6136 
  6137 * The previous version of HOL renamed to Old_HOL;
  6138 
  6139 * The new version of HOL (previously called CHOL) uses a curried syntax
  6140 for functions.  Application looks like f a b instead of f(a,b);
  6141 
  6142 * Mutually recursive inductive definitions finally work in HOL;
  6143 
  6144 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6145 translates to the operator "split";
  6146 
  6147 
  6148 
  6149 New in Isabelle94-3
  6150 -------------------
  6151 
  6152 * new infix operator, addss, allowing the classical reasoner to
  6153 perform simplification at each step of its search.  Example:
  6154         fast_tac (cs addss ss)
  6155 
  6156 * a new logic, CHOL, the same as HOL, but with a curried syntax
  6157 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  6158 look like (a,b) instead of <a,b>;
  6159 
  6160 * PLEASE NOTE: CHOL will eventually replace HOL!
  6161 
  6162 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  6163 It translates to the operator "split".  A new theory of integers is available;
  6164 
  6165 * In ZF, integer numerals now denote two's-complement binary integers.
  6166 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  6167 
  6168 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  6169 of the Axiom of Choice;
  6170 
  6171 
  6172 
  6173 New in Isabelle94-2
  6174 -------------------
  6175 
  6176 * Significantly faster resolution;
  6177 
  6178 * the different sections in a .thy file can now be mixed and repeated
  6179 freely;
  6180 
  6181 * Database of theorems for FOL, HOL and ZF.  New
  6182 commands including qed, qed_goal and bind_thm store theorems in the database.
  6183 
  6184 * Simple database queries: return a named theorem (get_thm) or all theorems of
  6185 a given theory (thms_of), or find out what theory a theorem was proved in
  6186 (theory_of_thm);
  6187 
  6188 * Bugs fixed in the inductive definition and datatype packages;
  6189 
  6190 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  6191 and HOL_dup_cs obsolete;
  6192 
  6193 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  6194 have been removed;
  6195 
  6196 * Simpler definition of function space in ZF;
  6197 
  6198 * new results about cardinal and ordinal arithmetic in ZF;
  6199 
  6200 * 'subtype' facility in HOL for introducing new types as subsets of existing
  6201 types;
  6202 
  6203 :mode=text:wrap=hard:maxLineLen=72: