NEWS
author haftmann
Fri Mar 27 10:12:55 2009 +0100 (2009-03-27)
changeset 30741 9e23e3ea7edd
parent 30728 f0aeca99b5d9
parent 30740 2d3ae5a7edb2
child 30845 9a887484de53
permissions -rw-r--r--
merged
     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 the Tutorial on Locales for
   143 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, and can be marked as mandatory (syntax: "name!:") or
   158 optional (syntax "name?:").  The default depends for plain "name:"
   159 depends on the situation where a locale expression is used: in
   160 commands 'locale' and 'sublocale' prefixes are optional, in
   161 'interpretation' and 'interpret' prefixes are mandatory.  Old-style
   162 implicit qualifiers derived from the parameter names of a locale are
   163 no longer generated.
   164 
   165 - "sublocale l < e" replaces "interpretation l < e".  The
   166 instantiation clause in "interpretation" and "interpret" (square
   167 brackets) is no longer available.  Use locale expressions.
   168 
   169 - When converting proof scripts, be sure to mandatory qualifiers in
   170 'interpretation' and 'interpret' should be retained by default, even
   171 if this is an INCOMPATIBILITY compared to former behaviour.
   172 Qualifiers in locale expressions range over a single locale instance
   173 only.
   174 
   175 * Command 'instance': attached definitions no longer accepted.
   176 INCOMPATIBILITY, use proper 'instantiation' target.
   177 
   178 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   179 
   180 * The 'axiomatization' command now only works within a global theory
   181 context.  INCOMPATIBILITY.
   182 
   183 * New 'find_theorems' criterion "solves" matching theorems that
   184 directly solve the current goal.
   185 
   186 * Auto solve feature for main theorem statements (cf. option in Proof
   187 General Isabelle settings menu, disabled by default).  Whenever a new
   188 goal is stated, "find_theorems solves" is called; any theorems that
   189 could solve the lemma directly are listed as part of the goal state.
   190 
   191 * Command 'find_consts' searches for constants based on type and name
   192 patterns, e.g.
   193 
   194     find_consts "_ => bool"
   195 
   196 By default, matching is against subtypes, but it may be restricted to
   197 the whole type.  Searching by name is possible.  Multiple queries are
   198 conjunctive and queries may be negated by prefixing them with a
   199 hyphen:
   200 
   201     find_consts strict: "_ => bool" name: "Int" -"int => int"
   202 
   203 * Command 'local_setup' is similar to 'setup', but operates on a local
   204 theory context.
   205 
   206 
   207 *** Document preparation ***
   208 
   209 * Antiquotation @{lemma} now imitates a regular terminal proof,
   210 demanding keyword 'by' and supporting the full method expression
   211 syntax just like the Isar command 'by'.
   212 
   213 
   214 *** HOL ***
   215 
   216 * Theory Library/Polynomial.thy defines an abstract type 'a poly of
   217 univariate polynomials with coefficients of type 'a.  In addition to
   218 the standard ring operations, it also supports div and mod.  Code
   219 generation is also supported, using list-style constructors.
   220 
   221 * Theory Library/Inner_Product.thy defines a class of real_inner for
   222 real inner product spaces, with an overloaded operation inner :: 'a =>
   223 'a => real.  Class real_inner is a subclass of real_normed_vector from
   224 RealVector.thy.
   225 
   226 * Theory Library/Product_Vector.thy provides instances for the product
   227 type 'a * 'b of several classes from RealVector.thy and
   228 Inner_Product.thy.  Definitions of addition, subtraction, scalar
   229 multiplication, norms, and inner products are included.
   230 
   231 * Theory Library/Bit.thy defines the field "bit" of integers modulo 2.
   232 In addition to the field operations, numerals and case syntax are also
   233 supported.
   234 
   235 * Theory Library/Diagonalize.thy provides constructive version of
   236 Cantor's first diagonalization argument.
   237 
   238 * New predicate "strict_mono" classifies strict functions on partial orders.
   239 With strict functions on linear orders, reasoning about (in)equalities is
   240 facilitated by theorems "strict_mono_eq", "strict_mono_less_eq" and "strict_mono_less".
   241 
   242 * Some set operations are now proper qualified constants with authentic syntax.
   243 INCOMPATIBILITY:
   244 
   245     op Int ~>   Set.Int
   246     op Un ~>    Set.Un
   247     INTER ~>    Set.INTER
   248     UNION ~>    Set.UNION
   249     Inter ~>    Set.Inter
   250     Union ~>    Set.Union
   251     {} ~>       Set.empty
   252     UNIV ~>     Set.UNIV
   253 
   254 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in theory
   255 Set.
   256 
   257 * Auxiliary class "itself" has disappeared -- classes without any parameter
   258 are treated as expected by the 'class' command.
   259 
   260 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   261 
   262 * Common decision procedures (Cooper, MIR, Ferrack, Approximation, Dense_Linear_Order)
   263 now in directory HOL/Decision_Procs.
   264 
   265 * Theory HOL/Decision_Procs/Approximation.thy provides the new proof method
   266 "approximation".  It proves formulas on real values by using interval arithmetic.
   267 In the formulas are also the transcendental functions sin, cos, tan, atan, ln,
   268 exp and the constant pi are allowed. For examples see
   269 HOL/Descision_Procs/ex/Approximation_Ex.thy.
   270 
   271 * Theory "Reflection" now resides in HOL/Library.
   272 
   273 * Entry point to Word library now simply named "Word".  INCOMPATIBILITY.
   274 
   275 * Made source layout more coherent with logical distribution
   276 structure:
   277 
   278     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   279     src/HOL/Library/Code_Message.thy ~> src/HOL/
   280     src/HOL/Library/GCD.thy ~> src/HOL/
   281     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   282     src/HOL/Library/Parity.thy ~> src/HOL/
   283     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   284     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   285     src/HOL/Real/Lubs.thy ~> src/HOL/
   286     src/HOL/Real/PReal.thy ~> src/HOL/
   287     src/HOL/Real/Rational.thy ~> src/HOL/
   288     src/HOL/Real/RComplete.thy ~> src/HOL/
   289     src/HOL/Real/RealDef.thy ~> src/HOL/
   290     src/HOL/Real/RealPow.thy ~> src/HOL/
   291     src/HOL/Real/Real.thy ~> src/HOL/
   292     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   293     src/HOL/Complex/Complex.thy ~> src/HOL/
   294     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   295     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   296     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   297     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   298     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   299     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   300     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   301     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   302     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   303     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   304     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   305     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   306     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   307     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   308     src/HOL/Real/Float ~> src/HOL/Library/
   309     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   310     src/HOL/Real/RealVector.thy ~> src/HOL/
   311 
   312     src/HOL/arith_data.ML ~> src/HOL/Tools
   313     src/HOL/hologic.ML ~> src/HOL/Tools
   314     src/HOL/simpdata.ML ~> src/HOL/Tools
   315     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   316     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   317     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   318     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   319     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   320     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   321     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   322 
   323     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   324     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   325     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   326     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   327     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   328     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   329 
   330 * If methods "eval" and "evaluation" encounter a structured proof state
   331 with !!/==>, only the conclusion is evaluated to True (if possible),
   332 avoiding strange error messages.
   333 
   334 * Simplifier: simproc for let expressions now unfolds if bound variable
   335 occurs at most once in let expression body.  INCOMPATIBILITY.
   336 
   337 * New attribute "arith" for facts that should always be used automaticaly
   338 by arithmetic. It is intended to be used locally in proofs, eg
   339 assumes [arith]: "x > 0"
   340 Global usage is discouraged because of possible performance impact.
   341 
   342 * New classes "top" and "bot" with corresponding operations "top" and "bot"
   343 in theory Orderings;  instantiation of class "complete_lattice" requires
   344 instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   345 
   346 * Changed definition lemma "less_fun_def" in order to provide an instance
   347 for preorders on functions;  use lemma "less_le" instead.  INCOMPATIBILITY.
   348 
   349 * Unified theorem tables for both code code generators.  Thus
   350 [code func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   351 
   352 * Constants "undefined" and "default" replace "arbitrary".  Usually
   353 "undefined" is the right choice to replace "arbitrary", though logically
   354 there is no difference.  INCOMPATIBILITY.
   355 
   356 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   357 Posix processes.  Avoids potentially expensive forking of the ML
   358 process.  New thread-based implementation also works on non-Unix
   359 platforms (Cygwin).  Provers are no longer hardwired, but defined
   360 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   361 commands are covered in the isar-ref manual.
   362 
   363 * Wrapper scripts for remote SystemOnTPTP service allows to use
   364 sledgehammer without local ATP installation (Vampire etc.). Other
   365 provers may be included via suitable ML wrappers, see also
   366 src/HOL/ATP_Linkup.thy.
   367 
   368 * Normalization by evaluation now allows non-leftlinear equations.
   369 Declare with attribute [code nbe].
   370 
   371 * Command "value" now integrates different evaluation
   372 mechanisms.  The result of the first successful evaluation mechanism
   373 is printed.  In square brackets a particular named evaluation
   374 mechanisms may be specified (currently, [SML], [code] or [nbe]).  See
   375 further src/HOL/ex/Eval_Examples.thy.
   376 
   377 * New method "sizechange" to automate termination proofs using (a
   378 modification of) the size-change principle. Requires SAT solver. See
   379 src/HOL/ex/Termination.thy for examples.
   380 
   381 * HOL/Orderings: class "wellorder" moved here, with explicit induction
   382 rule "less_induct" as assumption.  For instantiation of "wellorder" by
   383 means of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.
   384 
   385 * HOL/Orderings: added class "preorder" as superclass of "order".
   386 INCOMPATIBILITY: Instantiation proofs for order, linorder
   387 etc. slightly changed.  Some theorems named order_class.* now named
   388 preorder_class.*.
   389 
   390 * HOL/Relation:
   391 Renamed "refl" to "refl_on", "reflexive" to "refl, "diag" to "Id_on".
   392 
   393 * HOL/Finite_Set: added a new fold combinator of type
   394   ('a => 'b => 'b) => 'b => 'a set => 'b
   395 Occasionally this is more convenient than the old fold combinator which is
   396 now defined in terms of the new one and renamed to fold_image.
   397 
   398 * HOL/Ring_and_Field and HOL/OrderedGroup: The lemmas "group_simps" and
   399 "ring_simps" have been replaced by "algebra_simps" (which can be extended with
   400 further lemmas!). At the moment both still exist but the former will disappear
   401 at some point.
   402 
   403 * HOL/Power: Lemma power_Suc is now declared as a simp rule in class
   404 recpower.  Type-specific simp rules for various recpower types have
   405 been removed.  INCOMPATIBILITY.  Rename old lemmas as follows:
   406 
   407 rat_power_0    -> power_0
   408 rat_power_Suc  -> power_Suc
   409 realpow_0      -> power_0
   410 realpow_Suc    -> power_Suc
   411 complexpow_0   -> power_0
   412 complexpow_Suc -> power_Suc
   413 power_poly_0   -> power_0
   414 power_poly_Suc -> power_Suc
   415 
   416 * HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
   417 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   418 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   419 of lemmas from Divides has been generalized from nat to class
   420 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   421 renames resulting from duplicate elimination:
   422 
   423     dvd_def_mod ~>          dvd_eq_mod_eq_0
   424     zero_dvd_iff ~>         dvd_0_left_iff
   425     dvd_0 ~>                dvd_0_right
   426     DIVISION_BY_ZERO_DIV ~> div_by_0
   427     DIVISION_BY_ZERO_MOD ~> mod_by_0
   428     mult_div ~>             div_mult_self2_is_id
   429     mult_mod ~>             mod_mult_self2_is_0
   430 
   431 * HOL/IntDiv: removed many lemmas that are instances of class-based
   432 generalizations (from Divides and Ring_and_Field).
   433 INCOMPATIBILITY. Rename old lemmas as follows:
   434 
   435 dvd_diff               -> nat_dvd_diff
   436 dvd_zminus_iff         -> dvd_minus_iff
   437 mod_add1_eq            -> mod_add_eq
   438 mod_mult1_eq           -> mod_mult_right_eq
   439 mod_mult1_eq'          -> mod_mult_left_eq
   440 mod_mult_distrib_mod   -> mod_mult_eq
   441 nat_mod_add_left_eq    -> mod_add_left_eq
   442 nat_mod_add_right_eq   -> mod_add_right_eq
   443 nat_mod_div_trivial    -> mod_div_trivial
   444 nat_mod_mod_trivial    -> mod_mod_trivial
   445 zdiv_zadd_self1        -> div_add_self1
   446 zdiv_zadd_self2        -> div_add_self2
   447 zdiv_zmult_self1       -> div_mult_self2_is_id
   448 zdiv_zmult_self2       -> div_mult_self1_is_id
   449 zdvd_triv_left         -> dvd_triv_left
   450 zdvd_triv_right        -> dvd_triv_right
   451 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   452 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   453 zmod_zadd_left_eq      -> mod_add_left_eq
   454 zmod_zadd_right_eq     -> mod_add_right_eq
   455 zmod_zadd_self1        -> mod_add_self1
   456 zmod_zadd_self2        -> mod_add_self2
   457 zmod_zadd1_eq          -> mod_add_eq
   458 zmod_zdiff1_eq         -> mod_diff_eq
   459 zmod_zdvd_zmod         -> mod_mod_cancel
   460 zmod_zmod_cancel       -> mod_mod_cancel
   461 zmod_zmult_self1       -> mod_mult_self2_is_0
   462 zmod_zmult_self2       -> mod_mult_self1_is_0
   463 zmod_1                 -> mod_by_1
   464 zdiv_1                 -> div_by_1
   465 zdvd_abs1              -> abs_dvd_iff
   466 zdvd_abs2              -> dvd_abs_iff
   467 zdvd_refl              -> dvd_refl
   468 zdvd_trans             -> dvd_trans
   469 zdvd_zadd              -> dvd_add
   470 zdvd_zdiff             -> dvd_diff
   471 zdvd_zminus_iff        -> dvd_minus_iff
   472 zdvd_zminus2_iff       -> minus_dvd_iff
   473 zdvd_zmultD            -> dvd_mult_right
   474 zdvd_zmultD2           -> dvd_mult_left
   475 zdvd_zmult_mono        -> mult_dvd_mono
   476 zdvd_0_right           -> dvd_0_right
   477 zdvd_0_left            -> dvd_0_left_iff
   478 zdvd_1_left            -> one_dvd
   479 zminus_dvd_iff         -> minus_dvd_iff
   480 
   481 * HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   482 zlcm (for int); carried together from various gcd/lcm developements in
   483 the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
   484 corresponding theorems renamed accordingly.  INCOMPATIBILITY.  To
   485 recover tupled syntax, use syntax declarations like:
   486 
   487     hide (open) const gcd
   488     abbreviation gcd where
   489       "gcd == (%(a, b). GCD.gcd a b)"
   490     notation (output)
   491       GCD.gcd ("gcd '(_, _')")
   492 
   493 (analogously for lcm, zgcd, zlcm).
   494 
   495 * HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   496 
   497 * The real numbers offer decimal input syntax: 12.34 is translated into
   498   1234/10^2. This translation is not reversed upon output.
   499 
   500 * New ML antiquotation @{code}: takes constant as argument, generates
   501 corresponding code in background and inserts name of the corresponding
   502 resulting ML value/function/datatype constructor binding in place.
   503 All occurrences of @{code} with a single ML block are generated
   504 simultaneously.  Provides a generic and safe interface for
   505 instrumentalizing code generation.  See HOL/Decision_Procs/Ferrack for
   506 a more ambitious application.  In future you ought refrain from ad-hoc
   507 compiling generated SML code on the ML toplevel.  Note that (for technical
   508 reasons) @{code} cannot refer to constants for which user-defined
   509 serializations are set.  Refer to the corresponding ML counterpart
   510 directly in that cases.
   511 
   512 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   513 Complex_Main.thy remain as they are.
   514 
   515 * New image HOL-Plain provides a minimal HOL with the most important
   516 tools available (inductive, datatype, primrec, ...).  By convention
   517 the corresponding theory Plain should be ancestor of every further
   518 (library) theory.  Some library theories now have ancestor Plain
   519 (instead of Main), thus theory Main occasionally has to be imported
   520 explicitly.
   521 
   522 * The metis method now fails in the usual manner, rather than raising
   523 an exception, if it determines that it cannot prove the theorem.
   524 
   525 * The metis method no longer fails because the theorem is too trivial
   526 (contains the empty clause).
   527 
   528 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   529 as the structured Isar versions "cases" and "induct", cf. the
   530 corresponding "cases" and "induct" attributes.  Mutual induction rules
   531 are now presented as a list of individual projections
   532 (e.g. foo_bar.inducts for types foo and bar); the old format with
   533 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   534 rare situations a different rule is selected --- notably nested tuple
   535 elimination instead of former prod.exhaust: use explicit (case_tac t
   536 rule: prod.exhaust) here.
   537 
   538 * Attributes "cases", "induct", "coinduct" support "del" option.
   539 
   540 * Removed fact "case_split_thm", which duplicates "case_split".
   541 
   542 * Command 'rep_datatype': instead of theorem names the command now
   543 takes a list of terms denoting the constructors of the type to be
   544 represented as datatype.  The characteristic theorems have to be
   545 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   546 have disappeared in favour of existing ones:
   547 
   548     unit_induct                 ~> unit.induct
   549     prod_induct                 ~> prod.induct
   550     sum_induct                  ~> sum.induct
   551     Suc_Suc_eq                  ~> nat.inject
   552     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   553 
   554 * The option datatype has been moved to a new theory HOL/Option.thy.
   555 Renamed option_map to Option.map, and o2s to Option.set.
   556 
   557 * Library/Nat_Infinity: added addition, numeral syntax and more
   558 instantiations for algebraic structures.  Removed some duplicate
   559 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   560 
   561 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   562 menu.
   563 
   564 * Linear arithmetic now ignores all inequalities when
   565 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   566 
   567 
   568 *** HOL-Algebra ***
   569 
   570 * New locales for orders and lattices where the equivalence relation
   571 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   572 locales use a record structure with field eq for the equivalence.
   573 
   574 * New theory of factorial domains.
   575 
   576 * Units_l_inv and Units_r_inv are now simprules by default.
   577 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   578 and/or r_inv will now also require deletion of these lemmas.
   579 
   580 * Renamed the following theorems.  INCOMPATIBILITY.
   581 UpperD ~> Upper_memD
   582 LowerD ~> Lower_memD
   583 least_carrier ~> least_closed
   584 greatest_carrier ~> greatest_closed
   585 greatest_Lower_above ~> greatest_Lower_below
   586 one_zero ~> carrier_one_zero
   587 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   588 
   589 
   590 *** HOL-NSA ***
   591 
   592 * Created new image HOL-NSA, containing theories of nonstandard
   593 analysis which were previously part of HOL-Complex.  Entry point
   594 Hyperreal.thy remains valid, but theories formerly using
   595 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   596 
   597 
   598 *** ZF ***
   599 
   600 * Proof of Zorn's Lemma for partial orders.
   601 
   602 
   603 *** HOLCF ***
   604 
   605 * Reimplemented the simplification procedure for proving continuity
   606 subgoals.  The new simproc is extensible; users can declare additional
   607 continuity introduction rules with the attribute [cont2cont].
   608 
   609 * The continuity simproc now uses a different introduction rule for
   610 solving continuity subgoals on terms with lambda abstractions.  In
   611 some rare cases the new simproc may fail to solve subgoals that the
   612 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   613 Potential INCOMPATIBILITY.
   614 
   615 * The syntax of the fixrec package has changed.  The specification
   616 syntax now conforms in style to definition, primrec, function, etc.
   617 See HOLCF/ex/Fixrec_ex.thy for examples.  INCOMPATIBILITY.
   618 
   619 
   620 *** ML ***
   621 
   622 * High-level support for concurrent ML programming, see
   623 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   624 particularly convenient to organize independent functional
   625 computations.  The concept of "synchronized variables" provides a
   626 higher-order interface for components with shared state, avoiding the
   627 delicate details of mutexes and condition variables.  [Poly/ML 5.2.1
   628 or later]
   629 
   630 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   631 and Method.setup, as well as commands 'attribute_setup' and
   632 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   633 existing code accordingly, or use plain 'setup' together with old
   634 Method.add_method.
   635 
   636 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   637 to 'a -> thm, while results are always tagged with an authentic oracle
   638 name.  The Isar command 'oracle' is now polymorphic, no argument type
   639 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   640 accordingly.  Note that extra performance may be gained by producing
   641 the cterm carefully, avoiding slow Thm.cterm_of.
   642 
   643 * ML bindings produced via Isar commands are stored within the Isar
   644 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   645 become thread-safe and work with undo as expected (concerning
   646 top-level bindings, not side-effects on global references).
   647 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   648 compiler at runtime; really global bindings need to be given outside a
   649 theory. [Poly/ML 5.2 or later]
   650 
   651 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   652 context. Top-level ML bindings are stored within the proof context in
   653 a purely sequential fashion, disregarding the nested proof structure.
   654 ML bindings introduced by 'ML_prf' are discarded at the end of the
   655 proof.  [Poly/ML 5.2 or later]
   656 
   657 * Generic Toplevel.add_hook interface allows to analyze the result of
   658 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   659 for theorem dependency output of transactions resulting in a new
   660 theory state.
   661 
   662 * More systematic treatment of long names, abstract name bindings, and
   663 name space operations.  Basic operations on qualified names have been
   664 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   665 Long_Name.append.  Old type bstring has been mostly replaced by
   666 abstract type binding (see structure Binding), which supports precise
   667 qualification (by packages and local theory targets), as well as
   668 proper tracking of source positions.  INCOMPATIBILITY, need to wrap
   669 old bstring values into Binding.name, or better pass through abstract
   670 bindings everywhere.  See further src/Pure/General/long_name.ML,
   671 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   672 
   673 * Simplified interface for defining document antiquotations via
   674 ThyOutput.antiquotation, ThyOutput.output, and optionally
   675 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   676 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   677 examples.
   678 
   679 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   680 LocalTheory.note etc.) now refer to the *full* internal name, not the
   681 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   682 
   683 * Rules and tactics that read instantiations (read_instantiate,
   684 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   685 context, which is required for parsing and type-checking.  Moreover,
   686 the variables are specified as plain indexnames, not string encodings
   687 thereof.  INCOMPATIBILITY.
   688 
   689 * Disposed old type and term read functions (Sign.read_def_typ,
   690 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   691 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   692 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   693 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   694 resort for legacy applications.
   695 
   696 * Disposed old declarations, tactics, tactic combinators that refer to
   697 the simpset or claset of an implicit theory (such as Addsimps,
   698 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   699 embedded ML text, or local_simpset_of with a proper context passed as
   700 explicit runtime argument.
   701 
   702 * Antiquotations: block-structured compilation context indicated by
   703 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   704 
   705   @{let ?pat = term}                      - term abbreviation (HO matching)
   706   @{note name = fact}                     - fact abbreviation
   707   @{thm fact}                             - singleton fact (with attributes)
   708   @{thms fact}                            - general fact (with attributes)
   709   @{lemma prop by method}                 - singleton goal
   710   @{lemma prop by meth1 meth2}            - singleton goal
   711   @{lemma prop1 ... propN by method}      - general goal
   712   @{lemma prop1 ... propN by meth1 meth2} - general goal
   713   @{lemma (open) ...}                     - open derivation
   714 
   715 
   716 *** System ***
   717 
   718 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   719 Poly/ML 5.2.1 or later.
   720 
   721 * The Isabelle "emacs" tool provides a specific interface to invoke
   722 Proof General / Emacs, with more explicit failure if that is not
   723 installed (the old isabelle-interface script silently falls back on
   724 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   725 installation location of the Proof General distribution.
   726 
   727 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   728 the Isabelle process into a JVM/Scala application.  See
   729 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   730 process wrapper has been discontinued.)
   731 
   732 * Status messages (with exact source position information) are
   733 emitted, if proper markup print mode is enabled.  This allows
   734 user-interface components to provide detailed feedback on internal
   735 prover operations.
   736 
   737 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   738 
   739 
   740 
   741 New in Isabelle2008 (June 2008)
   742 -------------------------------
   743 
   744 *** General ***
   745 
   746 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   747 and updated, with formally checked references as hyperlinks.
   748 
   749 * Theory loader: use_thy (and similar operations) no longer set the
   750 implicit ML context, which was occasionally hard to predict and in
   751 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   752 provides a proper context already.
   753 
   754 * Theory loader: old-style ML proof scripts being *attached* to a thy
   755 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   756 'use' within a theory file will do the job.
   757 
   758 * Name space merge now observes canonical order, i.e. the second space
   759 is inserted into the first one, while existing entries in the first
   760 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   761 swap theory imports.
   762 
   763 * Syntax: symbol \<chi> is now considered a letter.  Potential
   764 INCOMPATIBILITY in identifier syntax etc.
   765 
   766 * Outer syntax: string tokens no longer admit escaped white space,
   767 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   768 white space without escapes.
   769 
   770 * Outer syntax: string tokens may contain arbitrary character codes
   771 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   772 "foo_bar".
   773 
   774 
   775 *** Pure ***
   776 
   777 * Context-dependent token translations.  Default setup reverts locally
   778 fixed variables, and adds hilite markup for undeclared frees.
   779 
   780 * Unused theorems can be found using the new command 'unused_thms'.
   781 There are three ways of invoking it:
   782 
   783 (1) unused_thms
   784      Only finds unused theorems in the current theory.
   785 
   786 (2) unused_thms thy_1 ... thy_n -
   787      Finds unused theorems in the current theory and all of its ancestors,
   788      excluding the theories thy_1 ... thy_n and all of their ancestors.
   789 
   790 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   791      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   792      their ancestors, excluding the theories thy_1 ... thy_n and all of
   793      their ancestors.
   794 
   795 In order to increase the readability of the list produced by
   796 unused_thms, theorems that have been created by a particular instance
   797 of a theory command such as 'inductive' or 'function' are considered
   798 to belong to the same "group", meaning that if at least one theorem in
   799 this group is used, the other theorems in the same group are no longer
   800 reported as unused.  Moreover, if all theorems in the group are
   801 unused, only one theorem in the group is displayed.
   802 
   803 Note that proof objects have to be switched on in order for
   804 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   805 usually the case when using Proof General with the default settings).
   806 
   807 * Authentic naming of facts disallows ad-hoc overwriting of previous
   808 theorems within the same name space.  INCOMPATIBILITY, need to remove
   809 duplicate fact bindings, or even accidental fact duplications.  Note
   810 that tools may maintain dynamically scoped facts systematically, using
   811 PureThy.add_thms_dynamic.
   812 
   813 * Command 'hide' now allows to hide from "fact" name space as well.
   814 
   815 * Eliminated destructive theorem database, simpset, claset, and
   816 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   817 update of theories within ML code.
   818 
   819 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   820 INCOMPATIBILITY, object-logics depending on former Pure require
   821 additional setup PureThy.old_appl_syntax_setup; object-logics
   822 depending on former CPure need to refer to Pure.
   823 
   824 * Commands 'use' and 'ML' are now purely functional, operating on
   825 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   826 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   827 INCOMPATIBILITY.
   828 
   829 * Command 'setup': discontinued implicit version with ML reference.
   830 
   831 * Instantiation target allows for simultaneous specification of class
   832 instance operations together with an instantiation proof.
   833 Type-checking phase allows to refer to class operations uniformly.
   834 See src/HOL/Complex/Complex.thy for an Isar example and
   835 src/HOL/Library/Eval.thy for an ML example.
   836 
   837 * Indexing of literal facts: be more serious about including only
   838 facts from the visible specification/proof context, but not the
   839 background context (locale etc.).  Affects `prop` notation and method
   840 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   841 situations.
   842 
   843 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   844 "(open)" option, which used to expose internal bound variables to the
   845 proof text.
   846 
   847 * Isar statements: removed obsolete case "rule_context".
   848 INCOMPATIBILITY, better use explicit fixes/assumes.
   849 
   850 * Locale proofs: default proof step now includes 'unfold_locales';
   851 hence 'proof' without argument may be used to unfold locale
   852 predicates.
   853 
   854 
   855 *** Document preparation ***
   856 
   857 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   858 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   859 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   860 spot); renamed link color from "darkblue" to "linkcolor" (default
   861 value unchanged, can be redefined via \definecolor); no longer sets
   862 "a4paper" option (unnecessary or even intrusive).
   863 
   864 * Antiquotation @{lemma A method} proves proposition A by the given
   865 method (either a method name or a method name plus (optional) method
   866 arguments in parentheses) and prints A just like @{prop A}.
   867 
   868 
   869 *** HOL ***
   870 
   871 * New primrec package.  Specification syntax conforms in style to
   872 definition/function/....  No separate induction rule is provided.  The
   873 "primrec" command distinguishes old-style and new-style specifications
   874 by syntax.  The former primrec package is now named OldPrimrecPackage.
   875 When adjusting theories, beware: constants stemming from new-style
   876 primrec specifications have authentic syntax.
   877 
   878 * Metis prover is now an order of magnitude faster, and also works
   879 with multithreading.
   880 
   881 * Metis: the maximum number of clauses that can be produced from a
   882 theorem is now given by the attribute max_clauses.  Theorems that
   883 exceed this number are ignored, with a warning printed.
   884 
   885 * Sledgehammer no longer produces structured proofs by default. To
   886 enable, declare [[sledgehammer_full = true]].  Attributes
   887 reconstruction_modulus, reconstruction_sorts renamed
   888 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   889 
   890 * Method "induct_scheme" derives user-specified induction rules
   891 from well-founded induction and completeness of patterns. This factors
   892 out some operations that are done internally by the function package
   893 and makes them available separately.  See
   894 src/HOL/ex/Induction_Scheme.thy for examples.
   895 
   896 * More flexible generation of measure functions for termination
   897 proofs: Measure functions can be declared by proving a rule of the
   898 form "is_measure f" and giving it the [measure_function] attribute.
   899 The "is_measure" predicate is logically meaningless (always true), and
   900 just guides the heuristic.  To find suitable measure functions, the
   901 termination prover sets up the goal "is_measure ?f" of the appropriate
   902 type and generates all solutions by prolog-style backwards proof using
   903 the declared rules.
   904 
   905 This setup also deals with rules like 
   906 
   907   "is_measure f ==> is_measure (list_size f)"
   908 
   909 which accommodates nested datatypes that recurse through lists.
   910 Similar rules are predeclared for products and option types.
   911 
   912 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   913 
   914   INCOMPATIBILITIES:
   915 
   916   - Definitions of overloaded constants on sets have to be replaced by
   917     definitions on => and bool.
   918 
   919   - Some definitions of overloaded operators on sets can now be proved
   920     using the definitions of the operators on => and bool.  Therefore,
   921     the following theorems have been renamed:
   922 
   923       subset_def   -> subset_eq
   924       psubset_def  -> psubset_eq
   925       set_diff_def -> set_diff_eq
   926       Compl_def    -> Compl_eq
   927       Sup_set_def  -> Sup_set_eq
   928       Inf_set_def  -> Inf_set_eq
   929       sup_set_def  -> sup_set_eq
   930       inf_set_def  -> inf_set_eq
   931 
   932   - Due to the incompleteness of the HO unification algorithm, some
   933     rules such as subst may require manual instantiation, if some of
   934     the unknowns in the rule is a set.
   935 
   936   - Higher order unification and forward proofs:
   937     The proof pattern
   938 
   939       have "P (S::'a set)" <...>
   940       then have "EX S. P S" ..
   941 
   942     no longer works (due to the incompleteness of the HO unification
   943     algorithm) and must be replaced by the pattern
   944 
   945       have "EX S. P S"
   946       proof
   947         show "P S" <...>
   948       qed
   949 
   950   - Calculational reasoning with subst (or similar rules):
   951     The proof pattern
   952 
   953       have "P (S::'a set)" <...>
   954       also have "S = T" <...>
   955       finally have "P T" .
   956 
   957     no longer works (for similar reasons as the previous example) and
   958     must be replaced by something like
   959 
   960       have "P (S::'a set)" <...>
   961       moreover have "S = T" <...>
   962       ultimately have "P T" by simp
   963 
   964   - Tactics or packages written in ML code:
   965     Code performing pattern matching on types via
   966 
   967       Type ("set", [T]) => ...
   968 
   969     must be rewritten. Moreover, functions like strip_type or
   970     binder_types no longer return the right value when applied to a
   971     type of the form
   972 
   973       T1 => ... => Tn => U => bool
   974 
   975     rather than
   976 
   977       T1 => ... => Tn => U set
   978 
   979 * Merged theories Wellfounded_Recursion, Accessible_Part and
   980 Wellfounded_Relations to theory Wellfounded.
   981 
   982 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   983 
   984 * Class finite no longer treats UNIV as class parameter.  Use class
   985 enum from theory Library/Enum instead to achieve a similar effect.
   986 INCOMPATIBILITY.
   987 
   988 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   989 and "Cons".  INCOMPATIBILITY.
   990 
   991 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   992 Potential INCOMPATIBILITY.
   993 
   994 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   995 injective_fst_snd removed, use split_eta and prod_eqI instead.
   996 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   997 
   998 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   999 the same name in theory Orderings:
  1000 
  1001   less_trans
  1002   less_linear
  1003   le_imp_less_or_eq
  1004   le_less_trans
  1005   less_le_trans
  1006   less_not_sym
  1007   less_asym
  1008 
  1009 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1010 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1011 and different variable names.
  1012 
  1013 * Library/Option_ord.thy: Canonical order on option type.
  1014 
  1015 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1016 finite maps.
  1017 
  1018 * Library/Countable.thy: Type class for countable types.
  1019 
  1020 * Theory Int: The representation of numerals has changed.  The infix
  1021 operator BIT and the bit datatype with constructors B0 and B1 have
  1022 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1023 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1024 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1025 accordingly.
  1026 
  1027 * Theory Nat: definition of <= and < on natural numbers no longer
  1028 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1029 le_def and less_def have disappeared.  Consider lemmas not_less
  1030 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1031 
  1032 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1033 (whose purpose mainly is for various fold_set functionals) have been
  1034 abandoned in favor of the existing algebraic classes
  1035 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1036 lower_semilattice (resp. upper_semilattice) and linorder.
  1037 INCOMPATIBILITY.
  1038 
  1039 * Theory Transitive_Closure: induct and cases rules now declare proper
  1040 case_names ("base" and "step").  INCOMPATIBILITY.
  1041 
  1042 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1043 lattices.  The form set-specific version is available as
  1044 Inductive.lfp_ordinal_induct_set.
  1045 
  1046 * Renamed theorems "power.simps" to "power_int.simps".
  1047 INCOMPATIBILITY.
  1048 
  1049 * Class semiring_div provides basic abstract properties of semirings
  1050 with division and modulo operations.  Subsumes former class dvd_mod.
  1051 
  1052 * Merged theories IntDef, Numeral and IntArith into unified theory
  1053 Int.  INCOMPATIBILITY.
  1054 
  1055 * Theory Library/Code_Index: type "index" now represents natural
  1056 numbers rather than integers.  INCOMPATIBILITY.
  1057 
  1058 * New class "uminus" with operation "uminus" (split of from class
  1059 "minus" which now only has operation "minus", binary).
  1060 INCOMPATIBILITY.
  1061 
  1062 * Constants "card", "internal_split", "option_map" now with authentic
  1063 syntax.  INCOMPATIBILITY.
  1064 
  1065 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1066 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1067 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1068 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1069 Sup_set_def, le_def, less_def, option_map_def now with object
  1070 equality.  INCOMPATIBILITY.
  1071 
  1072 * Records. Removed K_record, and replaced it by pure lambda term
  1073 %x. c. The simplifier setup is now more robust against eta expansion.
  1074 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1075 
  1076 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1077 
  1078 * Library/ListVector: new theory of arithmetic vector operations.
  1079 
  1080 * Library/Order_Relation: new theory of various orderings as sets of
  1081 pairs.  Defines preorders, partial orders, linear orders and
  1082 well-orders on sets and on types.
  1083 
  1084 
  1085 *** ZF ***
  1086 
  1087 * Renamed some theories to allow to loading both ZF and HOL in the
  1088 same session:
  1089 
  1090   Datatype  -> Datatype_ZF
  1091   Inductive -> Inductive_ZF
  1092   Int       -> Int_ZF
  1093   IntDiv    -> IntDiv_ZF
  1094   Nat       -> Nat_ZF
  1095   List      -> List_ZF
  1096   Main      -> Main_ZF
  1097 
  1098 INCOMPATIBILITY: ZF theories that import individual theories below
  1099 Main might need to be adapted.  Regular theory Main is still
  1100 available, as trivial extension of Main_ZF.
  1101 
  1102 
  1103 *** ML ***
  1104 
  1105 * ML within Isar: antiquotation @{const name} or @{const
  1106 name(typargs)} produces statically-checked Const term.
  1107 
  1108 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1109 (of the same name).  Removed obsolete print command.
  1110 
  1111 * Removed obsolete "use_legacy_bindings" function.
  1112 
  1113 * The ``print mode'' is now a thread-local value derived from a global
  1114 template (the former print_mode reference), thus access becomes
  1115 non-critical.  The global print_mode reference is for session
  1116 management only; user-code should use print_mode_value,
  1117 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1118 
  1119 * Functions system/system_out provide a robust way to invoke external
  1120 shell commands, with propagation of interrupts (requires Poly/ML
  1121 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1122 
  1123 
  1124 *** System ***
  1125 
  1126 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1127 in accordance with Proof General 3.7, which prefers GNU emacs.
  1128 
  1129 * isatool tty runs Isabelle process with plain tty interaction;
  1130 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1131 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1132 
  1133 * isatool browser now works with Cygwin as well, using general
  1134 "javapath" function defined in Isabelle process environment.
  1135 
  1136 * YXML notation provides a simple and efficient alternative to
  1137 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1138 isatool yxml as described in the Isabelle system manual.
  1139 
  1140 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1141 provides general wrapper for managing an Isabelle process in a robust
  1142 fashion, with ``cooked'' output from stdin/stderr.
  1143 
  1144 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1145 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1146 
  1147 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1148 way of changing the user's settings is via
  1149 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1150 script.
  1151 
  1152 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1153 cores of the underlying machine, which is a good starting point for
  1154 optimal performance tuning.  The corresponding usedir option -M allows
  1155 "max" as an alias for "0".  WARNING: does not work on certain versions
  1156 of Mac OS (with Poly/ML 5.1).
  1157 
  1158 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1159 adverse effect of Isabelle flooding interactive front-ends (notably
  1160 ProofGeneral / XEmacs).
  1161 
  1162 
  1163 
  1164 New in Isabelle2007 (November 2007)
  1165 -----------------------------------
  1166 
  1167 *** General ***
  1168 
  1169 * More uniform information about legacy features, notably a
  1170 warning/error of "Legacy feature: ...", depending on the state of the
  1171 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1172 legacy features will disappear eventually.
  1173 
  1174 * Theory syntax: the header format ``theory A = B + C:'' has been
  1175 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1176 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1177 
  1178 * Theory syntax: the old non-Isar theory file format has been
  1179 discontinued altogether.  Note that ML proof scripts may still be used
  1180 with Isar theories; migration is usually quite simple with the ML
  1181 function use_legacy_bindings.  INCOMPATIBILITY.
  1182 
  1183 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1184 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1185 quotes.
  1186 
  1187 * Theory loader: be more serious about observing the static theory
  1188 header specifications (including optional directories), but not the
  1189 accidental file locations of previously successful loads.  The strict
  1190 update policy of former update_thy is now already performed by
  1191 use_thy, so the former has been removed; use_thys updates several
  1192 theories simultaneously, just as 'imports' within a theory header
  1193 specification, but without merging the results.  Potential
  1194 INCOMPATIBILITY: may need to refine theory headers and commands
  1195 ROOT.ML which depend on load order.
  1196 
  1197 * Theory loader: optional support for content-based file
  1198 identification, instead of the traditional scheme of full physical
  1199 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1200 (cf. the system manual).  The new scheme allows to work with
  1201 non-finished theories in persistent session images, such that source
  1202 files may be moved later on without requiring reloads.
  1203 
  1204 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1205 file (with the same base name as the theory) are considered a legacy
  1206 feature, which will disappear eventually. Even now, the theory loader
  1207 no longer maintains dependencies on such files.
  1208 
  1209 * Syntax: the scope for resolving ambiguities via type-inference is
  1210 now limited to individual terms, instead of whole simultaneous
  1211 specifications as before. This greatly reduces the complexity of the
  1212 syntax module and improves flexibility by separating parsing and
  1213 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1214 'fixes' etc.) are required in rare situations.
  1215 
  1216 * Syntax: constants introduced by new-style packages ('definition',
  1217 'abbreviation' etc.) are passed through the syntax module in
  1218 ``authentic mode''. This means that associated mixfix annotations
  1219 really stick to such constants, independently of potential name space
  1220 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1221 trees are represented slightly differently, may need to adapt syntax
  1222 translations accordingly. Use CONST marker in 'translations' and
  1223 @{const_syntax} antiquotation in 'parse_translation' etc.
  1224 
  1225 * Legacy goal package: reduced interface to the bare minimum required
  1226 to keep existing proof scripts running.  Most other user-level
  1227 functions are now part of the OldGoals structure, which is *not* open
  1228 by default (consider isatool expandshort before open OldGoals).
  1229 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1230 these tend to cause confusion about the actual goal (!) context being
  1231 used here, which is not necessarily the same as the_context().
  1232 
  1233 * Command 'find_theorems': supports "*" wild-card in "name:"
  1234 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1235 support a specific search form (see ProofGeneral/CHANGES).
  1236 
  1237 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1238 by default, which means that "prems" (and also "fixed variables") are
  1239 suppressed from proof state output.  Note that the ProofGeneral
  1240 settings mechanism allows to change and save options persistently, but
  1241 older versions of Isabelle will fail to start up if a negative prems
  1242 limit is imposed.
  1243 
  1244 * Local theory targets may be specified by non-nested blocks of
  1245 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1246 contain definitions, theorems etc., including any derived mechanism
  1247 that has been implemented on top of these primitives.  This concept
  1248 generalizes the existing ``theorem (in ...)'' towards more versatility
  1249 and scalability.
  1250 
  1251 * Proof General interface: proper undo of final 'end' command;
  1252 discontinued Isabelle/classic mode (ML proof scripts).
  1253 
  1254 
  1255 *** Document preparation ***
  1256 
  1257 * Added antiquotation @{theory name} which prints the given name,
  1258 after checking that it refers to a valid ancestor theory in the
  1259 current context.
  1260 
  1261 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1262 check the given source text as ML type/structure, printing verbatim.
  1263 
  1264 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1265 "c args == rhs" given in the current context.  (Any number of
  1266 arguments may be given on the LHS.)
  1267 
  1268 
  1269 *** Pure ***
  1270 
  1271 * The 'class' package offers a combination of axclass and locale to
  1272 achieve Haskell-like type classes in Isabelle.  Definitions and
  1273 theorems within a class context produce both relative results (with
  1274 implicit parameters according to the locale context), and polymorphic
  1275 constants with qualified polymorphism (according to the class
  1276 context).  Within the body context of a 'class' target, a separate
  1277 syntax layer ("user space type system") takes care of converting
  1278 between global polymorphic consts and internal locale representation.
  1279 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1280 "isatool doc classes" provides a tutorial.
  1281 
  1282 * Generic code generator framework allows to generate executable
  1283 code for ML and Haskell (including Isabelle classes).  A short usage
  1284 sketch:
  1285 
  1286     internal compilation:
  1287         export_code <list of constants (term syntax)> in SML
  1288     writing SML code to a file:
  1289         export_code <list of constants (term syntax)> in SML <filename>
  1290     writing OCaml code to a file:
  1291         export_code <list of constants (term syntax)> in OCaml <filename>
  1292     writing Haskell code to a bunch of files:
  1293         export_code <list of constants (term syntax)> in Haskell <filename>
  1294 
  1295     evaluating closed propositions to True/False using code generation:
  1296         method ``eval''
  1297 
  1298 Reasonable default setup of framework in HOL.
  1299 
  1300 Theorem attributs for selecting and transforming function equations theorems:
  1301 
  1302     [code fun]:        select a theorem as function equation for a specific constant
  1303     [code fun del]:    deselect a theorem as function equation for a specific constant
  1304     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1305     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1306 
  1307 User-defined serializations (target in {SML, OCaml, Haskell}):
  1308 
  1309     code_const <and-list of constants (term syntax)>
  1310       {(target) <and-list of const target syntax>}+
  1311 
  1312     code_type <and-list of type constructors>
  1313       {(target) <and-list of type target syntax>}+
  1314 
  1315     code_instance <and-list of instances>
  1316       {(target)}+
  1317         where instance ::= <type constructor> :: <class>
  1318 
  1319     code_class <and_list of classes>
  1320       {(target) <and-list of class target syntax>}+
  1321         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1322 
  1323 code_instance and code_class only are effective to target Haskell.
  1324 
  1325 For example usage see src/HOL/ex/Codegenerator.thy and
  1326 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1327 generation from Isabelle/HOL theories is available via "isatool doc
  1328 codegen".
  1329 
  1330 * Code generator: consts in 'consts_code' Isar commands are now
  1331 referred to by usual term syntax (including optional type
  1332 annotations).
  1333 
  1334 * Command 'no_translations' removes translation rules from theory
  1335 syntax.
  1336 
  1337 * Overloaded definitions are now actually checked for acyclic
  1338 dependencies.  The overloading scheme is slightly more general than
  1339 that of Haskell98, although Isabelle does not demand an exact
  1340 correspondence to type class and instance declarations.
  1341 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1342 exotic versions of overloading -- at the discretion of the user!
  1343 
  1344 Polymorphic constants are represented via type arguments, i.e. the
  1345 instantiation that matches an instance against the most general
  1346 declaration given in the signature.  For example, with the declaration
  1347 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1348 as c(nat).  Overloading is essentially simultaneous structural
  1349 recursion over such type arguments.  Incomplete specification patterns
  1350 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1351 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1352 Command 'print_theory' outputs the normalized system of recursive
  1353 equations, see section "definitions".
  1354 
  1355 * Configuration options are maintained within the theory or proof
  1356 context (with name and type bool/int/string), providing a very simple
  1357 interface to a poor-man's version of general context data.  Tools may
  1358 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1359 these values using Config.get etc.  Users may change options via an
  1360 associated attribute of the same name.  This form of context
  1361 declaration works particularly well with commands 'declare' or
  1362 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1363 very easy to avoid global references, which would not observe Isar
  1364 toplevel undo/redo and fail to work with multithreading.
  1365 
  1366 Various global ML references of Pure and HOL have been turned into
  1367 configuration options:
  1368 
  1369   Unify.search_bound		unify_search_bound
  1370   Unify.trace_bound		unify_trace_bound
  1371   Unify.trace_simp		unify_trace_simp
  1372   Unify.trace_types		unify_trace_types
  1373   Simplifier.simp_depth_limit	simp_depth_limit
  1374   Blast.depth_limit		blast_depth_limit
  1375   DatatypeProp.dtK		datatype_distinctness_limit
  1376   fast_arith_neq_limit  	fast_arith_neq_limit
  1377   fast_arith_split_limit	fast_arith_split_limit
  1378 
  1379 * Named collections of theorems may be easily installed as context
  1380 data using the functor NamedThmsFun (see also
  1381 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1382 attributes; there is also a toplevel print command.  This facility is
  1383 just a common case of general context data, which is the preferred way
  1384 for anything more complex than just a list of facts in canonical
  1385 order.
  1386 
  1387 * Isar: command 'declaration' augments a local theory by generic
  1388 declaration functions written in ML.  This enables arbitrary content
  1389 being added to the context, depending on a morphism that tells the
  1390 difference of the original declaration context wrt. the application
  1391 context encountered later on.
  1392 
  1393 * Isar: proper interfaces for simplification procedures.  Command
  1394 'simproc_setup' declares named simprocs (with match patterns, and body
  1395 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1396 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1397 
  1398 * Isar: an extra pair of brackets around attribute declarations
  1399 abbreviates a theorem reference involving an internal dummy fact,
  1400 which will be ignored later --- only the effect of the attribute on
  1401 the background context will persist.  This form of in-place
  1402 declarations is particularly useful with commands like 'declare' and
  1403 'using', for example ``have A using [[simproc a]] by simp''.
  1404 
  1405 * Isar: method "assumption" (and implicit closing of subproofs) now
  1406 takes simple non-atomic goal assumptions into account: after applying
  1407 an assumption as a rule the resulting subgoals are solved by atomic
  1408 assumption steps.  This is particularly useful to finish 'obtain'
  1409 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1410 without referring to the original premise "!!x. P x ==> thesis" in the
  1411 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1412 more permissive.
  1413 
  1414 * Isar: implicit use of prems from the Isar proof context is
  1415 considered a legacy feature.  Common applications like ``have A .''
  1416 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1417 referencing facts explicitly here improves readability and
  1418 maintainability of proof texts.
  1419 
  1420 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1421 the obtained context from the course of reasoning!  For example:
  1422 
  1423   assume "EX x y. A x & B y"   -- "any previous fact"
  1424   then guess x and y by clarify
  1425 
  1426 This technique is potentially adventurous, depending on the facts and
  1427 proof tools being involved here.
  1428 
  1429 * Isar: known facts from the proof context may be specified as literal
  1430 propositions, using ASCII back-quote syntax.  This works wherever
  1431 named facts used to be allowed so far, in proof commands, proof
  1432 methods, attributes etc.  Literal facts are retrieved from the context
  1433 according to unification of type and term parameters.  For example,
  1434 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1435 theorems in the current context, then these are valid literal facts:
  1436 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1437 
  1438 There is also a proof method "fact" which does the same composition
  1439 for explicit goal states, e.g. the following proof texts coincide with
  1440 certain special cases of literal facts:
  1441 
  1442   have "A" by fact                 ==  note `A`
  1443   have "A ==> B" by fact           ==  note `A ==> B`
  1444   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1445   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1446 
  1447 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1448 outer syntax.  Thus symbolic identifiers may be used without
  1449 additional white space in declarations like this: ``assume *: A''.
  1450 
  1451 * Isar: 'print_facts' prints all local facts of the current context,
  1452 both named and unnamed ones.
  1453 
  1454 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1455 
  1456   def x == "t" and y == "u"
  1457 
  1458 * Isar: added command 'unfolding', which is structurally similar to
  1459 'using', but affects both the goal state and facts by unfolding given
  1460 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1461 'unfolded' attribute may be replaced by first-class proof text.
  1462 
  1463 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1464 and command 'unfolding' now all support object-level equalities
  1465 (potentially conditional).  The underlying notion of rewrite rule is
  1466 analogous to the 'rule_format' attribute, but *not* that of the
  1467 Simplifier (which is usually more generous).
  1468 
  1469 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1470 premises of a theorem by n. Useful in conjunction with drule.
  1471 
  1472 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1473 method expression within a sandbox consisting of the first N
  1474 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1475 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1476 simplifies all new goals that emerge from applying rule foo to the
  1477 originally first one.
  1478 
  1479 * Isar: schematic goals are no longer restricted to higher-order
  1480 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1481 expected.
  1482 
  1483 * Isar: the conclusion of a long theorem statement is now either
  1484 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1485 (essentially a disjunction of cases with local parameters and
  1486 assumptions).  The latter allows to express general elimination rules
  1487 adequately; in this notation common elimination rules look like this:
  1488 
  1489   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1490     assumes "EX x. P x"
  1491     obtains x where "P x"
  1492 
  1493   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1494     assumes "A & B"
  1495     obtains A and B
  1496 
  1497   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1498     assumes "A | B"
  1499     obtains
  1500       A
  1501     | B
  1502 
  1503 The subsequent classical rules even refer to the formal "thesis"
  1504 explicitly:
  1505 
  1506   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1507     obtains "~ thesis"
  1508 
  1509   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1510     obtains "thesis ==> something"
  1511 
  1512 The actual proof of an 'obtains' statement is analogous to that of the
  1513 Isar proof element 'obtain', only that there may be several cases.
  1514 Optional case names may be specified in parentheses; these will be
  1515 available both in the present proof and as annotations in the
  1516 resulting rule, for later use with the 'cases' method (cf. attribute
  1517 case_names).
  1518 
  1519 * Isar: the assumptions of a long theorem statement are available as
  1520 "assms" fact in the proof context.  This is more appropriate than the
  1521 (historical) "prems", which refers to all assumptions of the current
  1522 context, including those from the target locale, proof body etc.
  1523 
  1524 * Isar: 'print_statement' prints theorems from the current theory or
  1525 proof context in long statement form, according to the syntax of a
  1526 top-level lemma.
  1527 
  1528 * Isar: 'obtain' takes an optional case name for the local context
  1529 introduction rule (default "that").
  1530 
  1531 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1532 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1533 to occur.
  1534 
  1535 * Pure: syntax "CONST name" produces a fully internalized constant
  1536 according to the current context.  This is particularly useful for
  1537 syntax translations that should refer to internal constant
  1538 representations independently of name spaces.
  1539 
  1540 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1541 instead of "FOO ". This allows multiple binder declarations to coexist
  1542 in the same context.  INCOMPATIBILITY.
  1543 
  1544 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1545 primitive that also works in a locale context (both for constants and
  1546 fixed variables). Type declaration and internal syntactic representation
  1547 of given constants retrieved from the context. Likewise, the
  1548 'no_notation' command allows to remove given syntax annotations from the
  1549 current context.
  1550 
  1551 * Isar/locales: new derived specification elements 'axiomatization',
  1552 'definition', 'abbreviation', which support type-inference, admit
  1553 object-level specifications (equality, equivalence).  See also the
  1554 isar-ref manual.  Examples:
  1555 
  1556   axiomatization
  1557     eq  (infix "===" 50) where
  1558     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1559 
  1560   definition "f x y = x + y + 1"
  1561   definition g where "g x = f x x"
  1562 
  1563   abbreviation
  1564     neq  (infix "=!=" 50) where
  1565     "x =!= y == ~ (x === y)"
  1566 
  1567 These specifications may be also used in a locale context.  Then the
  1568 constants being introduced depend on certain fixed parameters, and the
  1569 constant name is qualified by the locale base name.  An internal
  1570 abbreviation takes care for convenient input and output, making the
  1571 parameters implicit and using the original short name.  See also
  1572 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1573 entities from a monomorphic theory.
  1574 
  1575 Presently, abbreviations are only available 'in' a target locale, but
  1576 not inherited by general import expressions.  Also note that
  1577 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1578 'translations' in common applications.  The "no_abbrevs" print mode
  1579 prevents folding of abbreviations in term output.
  1580 
  1581 Concrete syntax is attached to specified constants in internal form,
  1582 independently of name spaces.  The parse tree representation is
  1583 slightly different -- use 'notation' instead of raw 'syntax', and
  1584 'translations' with explicit "CONST" markup to accommodate this.
  1585 
  1586 * Pure/Isar: unified syntax for new-style specification mechanisms
  1587 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1588 full type inference and dummy patterns ("_").  For example:
  1589 
  1590   definition "K x _ = x"
  1591 
  1592   inductive conj for A B
  1593   where "A ==> B ==> conj A B"
  1594 
  1595 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1596 the current context.  Print mode "no_abbrevs" prevents inversion of
  1597 abbreviations on output.
  1598 
  1599 * Isar/locales: improved parameter handling: use of locales "var" and
  1600 "struct" no longer necessary; - parameter renamings are no longer
  1601 required to be injective.  For example, this allows to define
  1602 endomorphisms as locale endom = homom mult mult h.
  1603 
  1604 * Isar/locales: changed the way locales with predicates are defined.
  1605 Instead of accumulating the specification, the imported expression is
  1606 now an interpretation.  INCOMPATIBILITY: different normal form of
  1607 locale expressions.  In particular, in interpretations of locales with
  1608 predicates, goals repesenting already interpreted fragments are not
  1609 removed automatically.  Use methods `intro_locales' and
  1610 `unfold_locales'; see below.
  1611 
  1612 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1613 provide backward reasoning on locales predicates.  The methods are
  1614 aware of interpretations and discharge corresponding goals.
  1615 `intro_locales' is less aggressive then `unfold_locales' and does not
  1616 unfold predicates to assumptions.
  1617 
  1618 * Isar/locales: the order in which locale fragments are accumulated
  1619 has changed.  This enables to override declarations from fragments due
  1620 to interpretations -- for example, unwanted simp rules.
  1621 
  1622 * Isar/locales: interpretation in theories and proof contexts has been
  1623 extended.  One may now specify (and prove) equations, which are
  1624 unfolded in interpreted theorems.  This is useful for replacing
  1625 defined concepts (constants depending on locale parameters) by
  1626 concepts already existing in the target context.  Example:
  1627 
  1628   interpretation partial_order ["op <= :: [int, int] => bool"]
  1629     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1630 
  1631 Typically, the constant `partial_order.less' is created by a
  1632 definition specification element in the context of locale
  1633 partial_order.
  1634 
  1635 * Method "induct": improved internal context management to support
  1636 local fixes and defines on-the-fly. Thus explicit meta-level
  1637 connectives !!  and ==> are rarely required anymore in inductive goals
  1638 (using object-logic connectives for this purpose has been long
  1639 obsolete anyway). Common proof patterns are explained in
  1640 src/HOL/Induct/Common_Patterns.thy, see also
  1641 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1642 examples.
  1643 
  1644 * Method "induct": improved handling of simultaneous goals. Instead of
  1645 introducing object-level conjunction, the statement is now split into
  1646 several conclusions, while the corresponding symbolic cases are nested
  1647 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1648 see src/HOL/Induct/Common_Patterns.thy, for example.
  1649 
  1650 * Method "induct": mutual induction rules are now specified as a list
  1651 of rule sharing the same induction cases. HOL packages usually provide
  1652 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1653 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1654 mutual induction rules differently, i.e. like this:
  1655 
  1656   (induct rule: foo_bar.inducts)
  1657   (induct set: foo bar)
  1658   (induct pred: foo bar)
  1659   (induct type: foo bar)
  1660 
  1661 The ML function ProjectRule.projections turns old-style rules into the
  1662 new format.
  1663 
  1664 * Method "coinduct": dual of induction, see
  1665 src/HOL/Library/Coinductive_List.thy for various examples.
  1666 
  1667 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1668 considered a legacy feature.
  1669 
  1670 * Attribute "symmetric" produces result with standardized schematic
  1671 variables (index 0).  Potential INCOMPATIBILITY.
  1672 
  1673 * Simplifier: by default the simplifier trace only shows top level
  1674 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1675 default. Thus there is less danger of being flooded by the trace. The
  1676 trace indicates where parts have been suppressed.
  1677   
  1678 * Provers/classical: removed obsolete classical version of elim_format
  1679 attribute; classical elim/dest rules are now treated uniformly when
  1680 manipulating the claset.
  1681 
  1682 * Provers/classical: stricter checks to ensure that supplied intro,
  1683 dest and elim rules are well-formed; dest and elim rules must have at
  1684 least one premise.
  1685 
  1686 * Provers/classical: attributes dest/elim/intro take an optional
  1687 weight argument for the rule (just as the Pure versions).  Weights are
  1688 ignored by automated tools, but determine the search order of single
  1689 rule steps.
  1690 
  1691 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1692 where the body does not mention the bound variable.  Note that dummy
  1693 patterns implicitly depend on their context of bounds, which makes
  1694 "{_. _}" match any set comprehension as expected.  Potential
  1695 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1696 constant "_idtdummy" in the binding position.
  1697 
  1698 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1699 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1700 for example "A -> B" => "Pi A (%_. B)".
  1701 
  1702 * Pure: 'class_deps' command visualizes the subclass relation, using
  1703 the graph browser tool.
  1704 
  1705 * Pure: 'print_theory' now suppresses certain internal declarations by
  1706 default; use '!' option for full details.
  1707 
  1708 
  1709 *** HOL ***
  1710 
  1711 * Method "metis" proves goals by applying the Metis general-purpose
  1712 resolution prover (see also http://gilith.com/software/metis/).
  1713 Examples are in the directory MetisExamples.  WARNING: the
  1714 Isabelle/HOL-Metis integration does not yet work properly with
  1715 multi-threading.
  1716   
  1717 * Command 'sledgehammer' invokes external automatic theorem provers as
  1718 background processes.  It generates calls to the "metis" method if
  1719 successful. These can be pasted into the proof.  Users do not have to
  1720 wait for the automatic provers to return.  WARNING: does not really
  1721 work with multi-threading.
  1722 
  1723 * New "auto_quickcheck" feature tests outermost goal statements for
  1724 potential counter-examples.  Controlled by ML references
  1725 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1726 5000 milliseconds).  Fails silently if statements is outside of
  1727 executable fragment, or any other codgenerator problem occurs.
  1728 
  1729 * New constant "undefined" with axiom "undefined x = undefined".
  1730 
  1731 * Added class "HOL.eq", allowing for code generation with polymorphic
  1732 equality.
  1733 
  1734 * Some renaming of class constants due to canonical name prefixing in
  1735 the new 'class' package:
  1736 
  1737     HOL.abs ~> HOL.abs_class.abs
  1738     HOL.divide ~> HOL.divide_class.divide
  1739     0 ~> HOL.zero_class.zero
  1740     1 ~> HOL.one_class.one
  1741     op + ~> HOL.plus_class.plus
  1742     op - ~> HOL.minus_class.minus
  1743     uminus ~> HOL.minus_class.uminus
  1744     op * ~> HOL.times_class.times
  1745     op < ~> HOL.ord_class.less
  1746     op <= > HOL.ord_class.less_eq
  1747     Nat.power ~> Power.power_class.power
  1748     Nat.size ~> Nat.size_class.size
  1749     Numeral.number_of ~> Numeral.number_class.number_of
  1750     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1751     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1752     Orderings.min ~> Orderings.ord_class.min
  1753     Orderings.max ~> Orderings.ord_class.max
  1754     Divides.op div ~> Divides.div_class.div
  1755     Divides.op mod ~> Divides.div_class.mod
  1756     Divides.op dvd ~> Divides.div_class.dvd
  1757 
  1758 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1759 
  1760 a) User-defined constants using any of the names "plus", "minus",
  1761 "times", "less" or "less_eq". The standard syntax translations for
  1762 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1763 names.
  1764 
  1765 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1766 INCOMPATIBILITY: use more specific names.
  1767 
  1768 c) Permutative equations (e.g. "a + b = b + a")
  1769 Since the change of names also changes the order of terms, permutative
  1770 rewrite rules may get applied in a different order. Experience shows
  1771 that this is rarely the case (only two adaptions in the whole Isabelle
  1772 distribution).  INCOMPATIBILITY: rewrite proofs
  1773 
  1774 d) ML code directly refering to constant names
  1775 This in general only affects hand-written proof tactics, simprocs and
  1776 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1777 Consider using @{const_name} antiquotation.
  1778 
  1779 * New class "default" with associated constant "default".
  1780 
  1781 * Function "sgn" is now overloaded and available on int, real, complex
  1782 (and other numeric types), using class "sgn".  Two possible defs of
  1783 sgn are given as equational assumptions in the classes sgn_if and
  1784 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1785 INCOMPATIBILITY.
  1786 
  1787 * Locale "partial_order" now unified with class "order" (cf. theory
  1788 Orderings), added parameter "less".  INCOMPATIBILITY.
  1789 
  1790 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1791 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1792 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1793 
  1794 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1795 changed order of proof goals in instance proofs.
  1796 
  1797 * The transitivity reasoner for partial and linear orders is set up
  1798 for classes "order" and "linorder".  Instances of the reasoner are available
  1799 in all contexts importing or interpreting the corresponding locales.
  1800 Method "order" invokes the reasoner separately; the reasoner
  1801 is also integrated with the Simplifier as a solver.  Diagnostic
  1802 command 'print_orders' shows the available instances of the reasoner
  1803 in the current context.
  1804 
  1805 * Localized monotonicity predicate in theory "Orderings"; integrated
  1806 lemmas max_of_mono and min_of_mono with this predicate.
  1807 INCOMPATIBILITY.
  1808 
  1809 * Formulation of theorem "dense" changed slightly due to integration
  1810 with new class dense_linear_order.
  1811 
  1812 * Uniform lattice theory development in HOL.
  1813 
  1814     constants "meet" and "join" now named "inf" and "sup"
  1815     constant "Meet" now named "Inf"
  1816 
  1817     classes "meet_semilorder" and "join_semilorder" now named
  1818       "lower_semilattice" and "upper_semilattice"
  1819     class "lorder" now named "lattice"
  1820     class "comp_lat" now named "complete_lattice"
  1821 
  1822     Instantiation of lattice classes allows explicit definitions
  1823     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1824 
  1825   INCOMPATIBILITY.  Theorem renames:
  1826 
  1827     meet_left_le            ~> inf_le1
  1828     meet_right_le           ~> inf_le2
  1829     join_left_le            ~> sup_ge1
  1830     join_right_le           ~> sup_ge2
  1831     meet_join_le            ~> inf_sup_ord
  1832     le_meetI                ~> le_infI
  1833     join_leI                ~> le_supI
  1834     le_meet                 ~> le_inf_iff
  1835     le_join                 ~> ge_sup_conv
  1836     meet_idempotent         ~> inf_idem
  1837     join_idempotent         ~> sup_idem
  1838     meet_comm               ~> inf_commute
  1839     join_comm               ~> sup_commute
  1840     meet_leI1               ~> le_infI1
  1841     meet_leI2               ~> le_infI2
  1842     le_joinI1               ~> le_supI1
  1843     le_joinI2               ~> le_supI2
  1844     meet_assoc              ~> inf_assoc
  1845     join_assoc              ~> sup_assoc
  1846     meet_left_comm          ~> inf_left_commute
  1847     meet_left_idempotent    ~> inf_left_idem
  1848     join_left_comm          ~> sup_left_commute
  1849     join_left_idempotent    ~> sup_left_idem
  1850     meet_aci                ~> inf_aci
  1851     join_aci                ~> sup_aci
  1852     le_def_meet             ~> le_iff_inf
  1853     le_def_join             ~> le_iff_sup
  1854     join_absorp2            ~> sup_absorb2
  1855     join_absorp1            ~> sup_absorb1
  1856     meet_absorp1            ~> inf_absorb1
  1857     meet_absorp2            ~> inf_absorb2
  1858     meet_join_absorp        ~> inf_sup_absorb
  1859     join_meet_absorp        ~> sup_inf_absorb
  1860     distrib_join_le         ~> distrib_sup_le
  1861     distrib_meet_le         ~> distrib_inf_le
  1862 
  1863     add_meet_distrib_left   ~> add_inf_distrib_left
  1864     add_join_distrib_left   ~> add_sup_distrib_left
  1865     is_join_neg_meet        ~> is_join_neg_inf
  1866     is_meet_neg_join        ~> is_meet_neg_sup
  1867     add_meet_distrib_right  ~> add_inf_distrib_right
  1868     add_join_distrib_right  ~> add_sup_distrib_right
  1869     add_meet_join_distribs  ~> add_sup_inf_distribs
  1870     join_eq_neg_meet        ~> sup_eq_neg_inf
  1871     meet_eq_neg_join        ~> inf_eq_neg_sup
  1872     add_eq_meet_join        ~> add_eq_inf_sup
  1873     meet_0_imp_0            ~> inf_0_imp_0
  1874     join_0_imp_0            ~> sup_0_imp_0
  1875     meet_0_eq_0             ~> inf_0_eq_0
  1876     join_0_eq_0             ~> sup_0_eq_0
  1877     neg_meet_eq_join        ~> neg_inf_eq_sup
  1878     neg_join_eq_meet        ~> neg_sup_eq_inf
  1879     join_eq_if              ~> sup_eq_if
  1880 
  1881     mono_meet               ~> mono_inf
  1882     mono_join               ~> mono_sup
  1883     meet_bool_eq            ~> inf_bool_eq
  1884     join_bool_eq            ~> sup_bool_eq
  1885     meet_fun_eq             ~> inf_fun_eq
  1886     join_fun_eq             ~> sup_fun_eq
  1887     meet_set_eq             ~> inf_set_eq
  1888     join_set_eq             ~> sup_set_eq
  1889     meet1_iff               ~> inf1_iff
  1890     meet2_iff               ~> inf2_iff
  1891     meet1I                  ~> inf1I
  1892     meet2I                  ~> inf2I
  1893     meet1D1                 ~> inf1D1
  1894     meet2D1                 ~> inf2D1
  1895     meet1D2                 ~> inf1D2
  1896     meet2D2                 ~> inf2D2
  1897     meet1E                  ~> inf1E
  1898     meet2E                  ~> inf2E
  1899     join1_iff               ~> sup1_iff
  1900     join2_iff               ~> sup2_iff
  1901     join1I1                 ~> sup1I1
  1902     join2I1                 ~> sup2I1
  1903     join1I1                 ~> sup1I1
  1904     join2I2                 ~> sup1I2
  1905     join1CI                 ~> sup1CI
  1906     join2CI                 ~> sup2CI
  1907     join1E                  ~> sup1E
  1908     join2E                  ~> sup2E
  1909 
  1910     is_meet_Meet            ~> is_meet_Inf
  1911     Meet_bool_def           ~> Inf_bool_def
  1912     Meet_fun_def            ~> Inf_fun_def
  1913     Meet_greatest           ~> Inf_greatest
  1914     Meet_lower              ~> Inf_lower
  1915     Meet_set_def            ~> Inf_set_def
  1916 
  1917     Sup_def                 ~> Sup_Inf
  1918     Sup_bool_eq             ~> Sup_bool_def
  1919     Sup_fun_eq              ~> Sup_fun_def
  1920     Sup_set_eq              ~> Sup_set_def
  1921 
  1922     listsp_meetI            ~> listsp_infI
  1923     listsp_meet_eq          ~> listsp_inf_eq
  1924 
  1925     meet_min                ~> inf_min
  1926     join_max                ~> sup_max
  1927 
  1928 * Added syntactic class "size"; overloaded constant "size" now has
  1929 type "'a::size ==> bool"
  1930 
  1931 * Internal reorganisation of `size' of datatypes: size theorems
  1932 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1933 simplification rules by default!); theorems "prod.size" now named
  1934 "*.size".
  1935 
  1936 * Class "div" now inherits from class "times" rather than "type".
  1937 INCOMPATIBILITY.
  1938 
  1939 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1940 Linorder etc.  have disappeared; operations defined in terms of
  1941 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1942 
  1943 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1944 
  1945 * HOL-Word: New extensive library and type for generic, fixed size
  1946 machine words, with arithemtic, bit-wise, shifting and rotating
  1947 operations, reflection into int, nat, and bool lists, automation for
  1948 linear arithmetic (by automatic reflection into nat or int), including
  1949 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1950 arithmetic type classes, supporting automatic simplification of
  1951 numerals on all operations.
  1952 
  1953 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1954 
  1955 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1956 
  1957 * Code generator library theories:
  1958   - Code_Integer represents HOL integers by big integer literals in target
  1959     languages.
  1960   - Code_Char represents HOL characters by character literals in target
  1961     languages.
  1962   - Code_Char_chr like Code_Char, but also offers treatment of character
  1963     codes; includes Code_Integer.
  1964   - Executable_Set allows to generate code for finite sets using lists.
  1965   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1966     denominator).
  1967   - Executable_Real implements a subset of real numbers, namly those
  1968     representable by rational numbers.
  1969   - Efficient_Nat implements natural numbers by integers, which in general will
  1970     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1971     includes Code_Integer.
  1972   - Code_Index provides an additional datatype index which is mapped to
  1973     target-language built-in integers.
  1974   - Code_Message provides an additional datatype message_string which is isomorphic to
  1975     strings; messages are mapped to target-language strings.
  1976 
  1977 * New package for inductive predicates
  1978 
  1979   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1980 
  1981     inductive
  1982       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1983       for z_1 :: U_1 and ... and z_n :: U_m
  1984     where
  1985       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1986     | ...
  1987 
  1988   with full support for type-inference, rather than
  1989 
  1990     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1991 
  1992     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1993     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1994 
  1995     inductive "s z_1 ... z_m"
  1996     intros
  1997       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1998       ...
  1999 
  2000   For backward compatibility, there is a wrapper allowing inductive
  2001   sets to be defined with the new package via
  2002 
  2003     inductive_set
  2004       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2005       for z_1 :: U_1 and ... and z_n :: U_m
  2006     where
  2007       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2008     | ...
  2009 
  2010   or
  2011 
  2012     inductive_set
  2013       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2014       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2015       for z_1 :: U_1 and ... and z_n :: U_m
  2016     where
  2017       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2018     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2019     | ...
  2020 
  2021   if the additional syntax "p ..." is required.
  2022 
  2023   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2024   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2025 
  2026   INCOMPATIBILITIES:
  2027 
  2028   - Since declaration and definition of inductive sets or predicates
  2029     is no longer separated, abbreviations involving the newly
  2030     introduced sets or predicates must be specified together with the
  2031     introduction rules after the 'where' keyword (see above), rather
  2032     than before the actual inductive definition.
  2033 
  2034   - The variables in induction and elimination rules are now
  2035     quantified in the order of their occurrence in the introduction
  2036     rules, rather than in alphabetical order. Since this may break
  2037     some proofs, these proofs either have to be repaired, e.g. by
  2038     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2039     statements of the form
  2040 
  2041       case (rule_i a_i_1 ... a_i_{k_i})
  2042 
  2043     or the old order of quantification has to be restored by explicitly adding
  2044     meta-level quantifiers in the introduction rules, i.e.
  2045 
  2046       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2047 
  2048   - The format of the elimination rules is now
  2049 
  2050       p z_1 ... z_m x_1 ... x_n ==>
  2051         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2052         ==> ... ==> P
  2053 
  2054     for predicates and
  2055 
  2056       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2057         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2058         ==> ... ==> P
  2059 
  2060     for sets rather than
  2061 
  2062       x : s z_1 ... z_m ==>
  2063         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2064         ==> ... ==> P
  2065 
  2066     This may require terms in goals to be expanded to n-tuples
  2067     (e.g. using case_tac or simplification with the split_paired_all
  2068     rule) before the above elimination rule is applicable.
  2069 
  2070   - The elimination or case analysis rules for (mutually) inductive
  2071     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2072     list of rules "p_1_..._p_k.elims" is no longer available.
  2073 
  2074 * New package "function"/"fun" for general recursive functions,
  2075 supporting mutual and nested recursion, definitions in local contexts,
  2076 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2077 for small examples, and the separate tutorial on the function
  2078 package. The old recdef "package" is still available as before, but
  2079 users are encouraged to use the new package.
  2080 
  2081 * Method "lexicographic_order" automatically synthesizes termination
  2082 relations as lexicographic combinations of size measures. 
  2083 
  2084 * Case-expressions allow arbitrary constructor-patterns (including
  2085 "_") and take their order into account, like in functional
  2086 programming.  Internally, this is translated into nested
  2087 case-expressions; missing cases are added and mapped to the predefined
  2088 constant "undefined". In complicated cases printing may no longer show
  2089 the original input but the internal form. Lambda-abstractions allow
  2090 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2091 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2092 variable.
  2093 
  2094 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2095 is an abbreviation for "of_nat :: nat => int". The simplification
  2096 rules for "of_nat" have been changed to work like "int" did
  2097 previously.  Potential INCOMPATIBILITY:
  2098   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2099   - of_nat_diff and of_nat_mult are no longer default simp rules
  2100 
  2101 * Method "algebra" solves polynomial equations over (semi)rings using
  2102 Groebner bases. The (semi)ring structure is defined by locales and the
  2103 tool setup depends on that generic context. Installing the method for
  2104 a specific type involves instantiating the locale and possibly adding
  2105 declarations for computation on the coefficients.  The method is
  2106 already instantiated for natural numbers and for the axiomatic class
  2107 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2108 CALCULEMUS 2007 for the general principles underlying this
  2109 architecture of context-aware proof-tools.
  2110 
  2111 * Method "ferrack" implements quantifier elimination over
  2112 special-purpose dense linear orders using locales (analogous to
  2113 "algebra"). The method is already installed for class
  2114 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2115 rat, etc.
  2116 
  2117 * Former constant "List.op @" now named "List.append".  Use ML
  2118 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2119 circumvent possible incompatibilities when working on ML level.
  2120 
  2121 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2122 
  2123 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2124 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2125 
  2126 * New syntax for Haskell-like list comprehension (input only), eg.
  2127 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2128 
  2129 * The special syntax for function "filter" has changed from [x :
  2130 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2131 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2132 
  2133 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2134 defined on nat only, as an abbreviation for [a..<Suc b]
  2135 INCOMPATIBILITY.
  2136 
  2137 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2138 
  2139 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2140 
  2141 * New lemma collection field_simps (an extension of ring_simps) for
  2142 manipulating (in)equations involving division. Multiplies with all
  2143 denominators that can be proved to be non-zero (in equations) or
  2144 positive/negative (in inequations).
  2145 
  2146 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2147 have been improved and renamed to ring_simps, group_simps and
  2148 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2149 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2150 
  2151 * Theory Library/Commutative_Ring: switched from recdef to function
  2152 package; constants add, mul, pow now curried.  Infix syntax for
  2153 algebraic operations.
  2154 
  2155 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2156 INCOMPATIBILITY.
  2157 
  2158 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2159 INCOMPATIBILITY.
  2160 
  2161 * HOL/records: generalised field-update to take a function on the
  2162 field rather than the new value: r(|A := x|) is translated to A_update
  2163 (K x) r The K-combinator that is internally used is called K_record.
  2164 INCOMPATIBILITY: Usage of the plain update functions has to be
  2165 adapted.
  2166  
  2167 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2168 * x = 0, which are required for a semiring.  Richer structures do not
  2169 inherit from semiring_0 anymore, because this property is a theorem
  2170 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2171 there is more to prove, but this is mostly trivial.
  2172 
  2173 * Class "recpower" is generalized to arbitrary monoids, not just
  2174 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2175 commutativity or semiring properties additionally.
  2176 
  2177 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2178 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2179 better use 'abbreviation'.
  2180 
  2181 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2182 
  2183 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2184 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2185 significant changes for setting up numeral syntax for types:
  2186   - New constants Numeral.pred and Numeral.succ instead
  2187       of former Numeral.bin_pred and Numeral.bin_succ.
  2188   - Use integer operations instead of bin_add, bin_mult and so on.
  2189   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2190   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2191 
  2192 See src/HOL/Integ/IntArith.thy for an example setup.
  2193 
  2194 * Command 'normal_form' computes the normal form of a term that may
  2195 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2196 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2197 heavy-duty computations because the functions are compiled to ML
  2198 first.  Correspondingly, a method "normalization" is provided.  See
  2199 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2200 
  2201 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2202 25 like -->); output depends on the "iff" print_mode, the default is
  2203 "A = B" (with priority 50).
  2204 
  2205 * Relations less (<) and less_eq (<=) are also available on type bool.
  2206 Modified syntax to disallow nesting without explicit parentheses,
  2207 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2208 INCOMPATIBILITY.
  2209 
  2210 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2211 
  2212 * Relation composition operator "op O" now has precedence 75 and binds
  2213 stronger than union and intersection. INCOMPATIBILITY.
  2214 
  2215 * The old set interval syntax "{m..n(}" (and relatives) has been
  2216 removed.  Use "{m..<n}" (and relatives) instead.
  2217 
  2218 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2219 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2220 ``declare [[simproc del: neq]]''.
  2221 
  2222 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2223 True/False.
  2224 
  2225 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2226 
  2227 * Theorem setsum_mult renamed to setsum_right_distrib.
  2228 
  2229 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2230 ``rule'' method.
  2231 
  2232 * Reimplemented methods "sat" and "satx", with several improvements:
  2233 goals no longer need to be stated as "<prems> ==> False", equivalences
  2234 (i.e. "=" on type bool) are handled, variable names of the form
  2235 "lit_<n>" are no longer reserved, significant speedup.
  2236 
  2237 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2238 zChaff is still supported as well.
  2239 
  2240 * 'inductive' and 'datatype': provide projections of mutual rules,
  2241 bundled as foo_bar.inducts;
  2242 
  2243 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2244 Library.
  2245 
  2246 * Library: moved theory Accessible_Part to main HOL.
  2247 
  2248 * Library: added theory Coinductive_List of potentially infinite lists
  2249 as greatest fixed-point.
  2250 
  2251 * Library: added theory AssocList which implements (finite) maps as
  2252 association lists.
  2253 
  2254 * Method "evaluation" solves goals (i.e. a boolean expression)
  2255 efficiently by compiling it to ML.  The goal is "proved" (via an
  2256 oracle) if it evaluates to True.
  2257 
  2258 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2259 also when invoked by the simplifier.  This results in the Simplifier
  2260 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2261 Configuration option fast_arith_split_limit=0 recovers the old
  2262 behavior.
  2263 
  2264 * Support for hex (0x20) and binary (0b1001) numerals.
  2265 
  2266 * New method: reify eqs (t), where eqs are equations for an
  2267 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2268 parameter, computes a term s::'b and a list xs::'a list and proves the
  2269 theorem I xs s = t. This is also known as reification or quoting. The
  2270 resulting theorem is applied to the subgoal to substitute t with I xs
  2271 s.  If t is omitted, the subgoal itself is reified.
  2272 
  2273 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2274 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2275 where f is supposed to be a computable function (in the sense of code
  2276 generattion). The method uses reify to compute s and xs as above then
  2277 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2278 r and finally gets the theorem t = r, which is again applied to the
  2279 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2280 
  2281 * Reflection: Automatic reification now handels binding, an example is
  2282 available in src/HOL/ex/ReflectionEx.thy
  2283 
  2284 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2285 command 'statespace' that is similar to 'record', but introduces an
  2286 abstract specification based on the locale infrastructure instead of
  2287 HOL types.  This leads to extra flexibility in composing state spaces,
  2288 in particular multiple inheritance and renaming of components.
  2289 
  2290 
  2291 *** HOL-Complex ***
  2292 
  2293 * Hyperreal: Functions root and sqrt are now defined on negative real
  2294 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2295 Nonnegativity side conditions have been removed from many lemmas, so
  2296 that more subgoals may now be solved by simplification; potential
  2297 INCOMPATIBILITY.
  2298 
  2299 * Real: new type classes formalize real normed vector spaces and
  2300 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2301 and norm :: 'a => real.
  2302 
  2303 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2304 reals into other types. The overloaded constant Reals :: 'a set is now
  2305 defined as range of_real; potential INCOMPATIBILITY.
  2306 
  2307 * Real: proper support for ML code generation, including 'quickcheck'.
  2308 Reals are implemented as arbitrary precision rationals.
  2309 
  2310 * Hyperreal: Several constants that previously worked only for the
  2311 reals have been generalized, so they now work over arbitrary vector
  2312 spaces. Type annotations may need to be added in some cases; potential
  2313 INCOMPATIBILITY.
  2314 
  2315   Infinitesimal  :: ('a::real_normed_vector) star set
  2316   HFinite        :: ('a::real_normed_vector) star set
  2317   HInfinite      :: ('a::real_normed_vector) star set
  2318   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2319   monad          :: ('a::real_normed_vector) star => 'a star set
  2320   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2321   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2322   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2323   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2324   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2325   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2326   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2327   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2328   sgn            :: 'a::real_normed_vector => 'a
  2329   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2330 
  2331 * Complex: Some complex-specific constants are now abbreviations for
  2332 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2333 hnorm.  Other constants have been entirely removed in favor of the
  2334 polymorphic versions (INCOMPATIBILITY):
  2335 
  2336   approx        <-- capprox
  2337   HFinite       <-- CFinite
  2338   HInfinite     <-- CInfinite
  2339   Infinitesimal <-- CInfinitesimal
  2340   monad         <-- cmonad
  2341   galaxy        <-- cgalaxy
  2342   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2343   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2344   (ns)deriv     <-- (ns)cderiv
  2345 
  2346 
  2347 *** HOL-Algebra ***
  2348 
  2349 * Formalisation of ideals and the quotient construction over rings.
  2350 
  2351 * Order and lattice theory no longer based on records.
  2352 INCOMPATIBILITY.
  2353 
  2354 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2355 greatest_closed.  INCOMPATIBILITY.
  2356 
  2357 * Method algebra is now set up via an attribute.  For examples see
  2358 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2359 of algebraic structures.
  2360 
  2361 * Renamed theory CRing to Ring.
  2362 
  2363 
  2364 *** HOL-Nominal ***
  2365 
  2366 * Substantial, yet incomplete support for nominal datatypes (binding
  2367 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2368 src/HOL/Nominal/Examples.  Prospective users should consult
  2369 http://isabelle.in.tum.de/nominal/
  2370 
  2371 
  2372 *** ML ***
  2373 
  2374 * ML basics: just one true type int, which coincides with IntInf.int
  2375 (even on SML/NJ).
  2376 
  2377 * ML within Isar: antiquotations allow to embed statically-checked
  2378 formal entities in the source, referring to the context available at
  2379 compile-time.  For example:
  2380 
  2381 ML {* @{sort "{zero,one}"} *}
  2382 ML {* @{typ "'a => 'b"} *}
  2383 ML {* @{term "%x. x"} *}
  2384 ML {* @{prop "x == y"} *}
  2385 ML {* @{ctyp "'a => 'b"} *}
  2386 ML {* @{cterm "%x. x"} *}
  2387 ML {* @{cprop "x == y"} *}
  2388 ML {* @{thm asm_rl} *}
  2389 ML {* @{thms asm_rl} *}
  2390 ML {* @{type_name c} *}
  2391 ML {* @{type_syntax c} *}
  2392 ML {* @{const_name c} *}
  2393 ML {* @{const_syntax c} *}
  2394 ML {* @{context} *}
  2395 ML {* @{theory} *}
  2396 ML {* @{theory Pure} *}
  2397 ML {* @{theory_ref} *}
  2398 ML {* @{theory_ref Pure} *}
  2399 ML {* @{simpset} *}
  2400 ML {* @{claset} *}
  2401 ML {* @{clasimpset} *}
  2402 
  2403 The same works for sources being ``used'' within an Isar context.
  2404 
  2405 * ML in Isar: improved error reporting; extra verbosity with
  2406 ML_Context.trace enabled.
  2407 
  2408 * Pure/General/table.ML: the join operations now works via exceptions
  2409 DUP/SAME instead of type option. This is simpler in simple cases, and
  2410 admits slightly more efficient complex applications.
  2411 
  2412 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2413 use Context.generic instead of just theory.
  2414 
  2415 * Pure: datatype Context.generic joins theory/Proof.context and
  2416 provides some facilities for code that works in either kind of
  2417 context, notably GenericDataFun for uniform theory and proof data.
  2418 
  2419 * Pure: simplified internal attribute type, which is now always
  2420 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2421 local (Proof.context) attributes have been discontinued, while
  2422 minimizing code duplication. Thm.rule_attribute and
  2423 Thm.declaration_attribute build canonical attributes; see also structure
  2424 Context for further operations on Context.generic, notably
  2425 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2426 declarations and definitions.
  2427 
  2428 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2429 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2430 init only required for impure data. INCOMPATIBILITY: empty really need
  2431 to be empty (no dependencies on theory content!)
  2432 
  2433 * Pure/kernel: consts certification ignores sort constraints given in
  2434 signature declarations. (This information is not relevant to the
  2435 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2436 potential INCOMPATIBILITY.
  2437 
  2438 * Pure: axiomatic type classes are now purely definitional, with
  2439 explicit proofs of class axioms and super class relations performed
  2440 internally. See Pure/axclass.ML for the main internal interfaces --
  2441 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2442 AxClass.axiomatize_class/classrel/arity supersede
  2443 Sign.add_classes/classrel/arities.
  2444 
  2445 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2446 global/local versions on theory vs. Proof.context have been
  2447 discontinued; Attrib.syntax and Method.syntax have been adapted
  2448 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2449 attributes, methods, etc.
  2450 
  2451 * Pure: several functions of signature "... -> theory -> theory * ..."
  2452 have been reoriented to "... -> theory -> ... * theory" in order to
  2453 allow natural usage in combination with the ||>, ||>>, |-> and
  2454 fold_map combinators.
  2455 
  2456 * Pure: official theorem names (closed derivations) and additional
  2457 comments (tags) are now strictly separate.  Name hints -- which are
  2458 maintained as tags -- may be attached any time without affecting the
  2459 derivation.
  2460 
  2461 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2462 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2463 achieve the old behaviour.
  2464 
  2465 * Pure: the "Goal" constant is now called "prop", supporting a
  2466 slightly more general idea of ``protecting'' meta-level rule
  2467 statements.
  2468 
  2469 * Pure: Logic.(un)varify only works in a global context, which is now
  2470 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2471 Logic.legacy_(un)varify as temporary workaround.
  2472 
  2473 * Pure: structure Name provides scalable operations for generating
  2474 internal variable names, notably Name.variants etc.  This replaces
  2475 some popular functions from term.ML:
  2476 
  2477   Term.variant		->  Name.variant
  2478   Term.variantlist	->  Name.variant_list
  2479   Term.invent_names	->  Name.invent_list
  2480 
  2481 Note that low-level renaming rarely occurs in new code -- operations
  2482 from structure Variable are used instead (see below).
  2483 
  2484 * Pure: structure Variable provides fundamental operations for proper
  2485 treatment of fixed/schematic variables in a context.  For example,
  2486 Variable.import introduces fixes for schematics of given facts and
  2487 Variable.export reverses the effect (up to renaming) -- this replaces
  2488 various freeze_thaw operations.
  2489 
  2490 * Pure: structure Goal provides simple interfaces for
  2491 init/conclude/finish and tactical prove operations (replacing former
  2492 Tactic.prove).  Goal.prove is the canonical way to prove results
  2493 within a given context; Goal.prove_global is a degraded version for
  2494 theory level goals, including a global Drule.standard.  Note that
  2495 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2496 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2497 in a locale context).
  2498 
  2499 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2500 and type checking (Syntax.check_term etc.), with common combinations
  2501 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2502 which are considered legacy and await removal.
  2503 
  2504 * Pure/Syntax: generic interfaces for type unchecking
  2505 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2506 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2507 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2508 available for convenience, but refer to the very same operations using
  2509 a mere theory instead of a full context.
  2510 
  2511 * Isar: simplified treatment of user-level errors, using exception
  2512 ERROR of string uniformly.  Function error now merely raises ERROR,
  2513 without any side effect on output channels.  The Isar toplevel takes
  2514 care of proper display of ERROR exceptions.  ML code may use plain
  2515 handle/can/try; cat_error may be used to concatenate errors like this:
  2516 
  2517   ... handle ERROR msg => cat_error msg "..."
  2518 
  2519 Toplevel ML code (run directly or through the Isar toplevel) may be
  2520 embedded into the Isar toplevel with exception display/debug like
  2521 this:
  2522 
  2523   Isar.toplevel (fn () => ...)
  2524 
  2525 INCOMPATIBILITY, removed special transform_error facilities, removed
  2526 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2527 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2528 -- use plain ERROR instead.
  2529 
  2530 * Isar: theory setup now has type (theory -> theory), instead of a
  2531 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2532 
  2533 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2534 ProofContext.debug/verbose flags.
  2535 
  2536 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2537 theory before entering a proof state.  Transactions now always see a
  2538 quasi-functional intermediate checkpoint, both in interactive and
  2539 batch mode.
  2540 
  2541 * Isar: simplified interfaces for outer syntax.  Renamed
  2542 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2543 OuterSyntax.add_parsers -- this functionality is now included in
  2544 OuterSyntax.command etc.  INCOMPATIBILITY.
  2545 
  2546 * Simplifier: the simpset of a running simplification process now
  2547 contains a proof context (cf. Simplifier.the_context), which is the
  2548 very context that the initial simpset has been retrieved from (by
  2549 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2550 (solver, looper etc.) may depend on arbitrary proof data.
  2551 
  2552 * Simplifier.inherit_context inherits the proof context (plus the
  2553 local bounds) of the current simplification process; any simproc
  2554 etc. that calls the Simplifier recursively should do this!  Removed
  2555 former Simplifier.inherit_bounds, which is already included here --
  2556 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2557 specify an explicit context using Simplifier.context/theory_context.
  2558 
  2559 * Simplifier/Classical Reasoner: more abstract interfaces
  2560 change_simpset/claset for modifying the simpset/claset reference of a
  2561 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2562 INCOMPATIBILITY.
  2563 
  2564 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2565 "Trueprop" etc.
  2566 
  2567 
  2568 *** System ***
  2569 
  2570 * settings: the default heap location within ISABELLE_HOME_USER now
  2571 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2572 Isabelle installations.
  2573 
  2574 * isabelle-process: option -S (secure mode) disables some critical
  2575 operations, notably runtime compilation and evaluation of ML source
  2576 code.
  2577 
  2578 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2579 
  2580 * Support for parallel execution, using native multicore support of
  2581 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2582 independent theories, according to the given theory header
  2583 specifications. The maximum number of worker threads is specified via
  2584 usedir option -M or the "max-threads" setting in Proof General. A
  2585 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2586 to 6 on a 8-core machine.  User-code needs to observe certain
  2587 guidelines for thread-safe programming, see appendix A in the Isar
  2588 Implementation manual.
  2589 
  2590 
  2591 
  2592 New in Isabelle2005 (October 2005)
  2593 ----------------------------------
  2594 
  2595 *** General ***
  2596 
  2597 * Theory headers: the new header syntax for Isar theories is
  2598 
  2599   theory <name>
  2600   imports <theory1> ... <theoryN>
  2601   uses <file1> ... <fileM>
  2602   begin
  2603 
  2604 where the 'uses' part is optional.  The previous syntax
  2605 
  2606   theory <name> = <theory1> + ... + <theoryN>:
  2607 
  2608 will disappear in the next release.  Use isatool fixheaders to convert
  2609 existing theory files.  Note that there is no change in ancient
  2610 non-Isar theories now, but these will disappear soon.
  2611 
  2612 * Theory loader: parent theories can now also be referred to via
  2613 relative and absolute paths.
  2614 
  2615 * Command 'find_theorems' searches for a list of criteria instead of a
  2616 list of constants. Known criteria are: intro, elim, dest, name:string,
  2617 simp:term, and any term. Criteria can be preceded by '-' to select
  2618 theorems that do not match. Intro, elim, dest select theorems that
  2619 match the current goal, name:s selects theorems whose fully qualified
  2620 name contain s, and simp:term selects all simplification rules whose
  2621 lhs match term.  Any other term is interpreted as pattern and selects
  2622 all theorems matching the pattern. Available in ProofGeneral under
  2623 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2624 
  2625   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2626 
  2627 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2628 matching the current goal as introduction rule and not having "HOL."
  2629 in their name (i.e. not being defined in theory HOL).
  2630 
  2631 * Command 'thms_containing' has been discontinued in favour of
  2632 'find_theorems'; INCOMPATIBILITY.
  2633 
  2634 * Communication with Proof General is now 8bit clean, which means that
  2635 Unicode text in UTF-8 encoding may be used within theory texts (both
  2636 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2637 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2638 
  2639   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2640   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2641 
  2642 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2643 Classical Reasoner.  Typical big applications run around 2 times
  2644 faster.
  2645 
  2646 
  2647 *** Document preparation ***
  2648 
  2649 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2650 of raw sources.  Only those symbols that do not require additional
  2651 LaTeX packages (depending on comments in isabellesym.sty) are
  2652 displayed properly, everything else is left verbatim.  isatool display
  2653 and isatool print are used as front ends (these are subject to the
  2654 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2655 
  2656 * Command tags control specific markup of certain regions of text,
  2657 notably folding and hiding.  Predefined tags include "theory" (for
  2658 theory begin and end), "proof" for proof commands, and "ML" for
  2659 commands involving ML code; the additional tags "visible" and
  2660 "invisible" are unused by default.  Users may give explicit tag
  2661 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2662 interpretation of tags is determined by the LaTeX job during document
  2663 preparation: see option -V of isatool usedir, or options -n and -t of
  2664 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2665 \isadroptag.
  2666 
  2667 Several document versions may be produced at the same time via isatool
  2668 usedir (the generated index.html will link all of them).  Typical
  2669 specifications include ''-V document=theory,proof,ML'' to present
  2670 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2671 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2672 these parts without any formal replacement text.  The Isabelle site
  2673 default settings produce ''document'' and ''outline'' versions as
  2674 specified above.
  2675 
  2676 * Several new antiquotations:
  2677 
  2678   @{term_type term} prints a term with its type annotated;
  2679 
  2680   @{typeof term} prints the type of a term;
  2681 
  2682   @{const const} is the same as @{term const}, but checks that the
  2683   argument is a known logical constant;
  2684 
  2685   @{term_style style term} and @{thm_style style thm} print a term or
  2686   theorem applying a "style" to it
  2687 
  2688   @{ML text}
  2689 
  2690 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2691 definitions, equations, inequations etc., 'concl' printing only the
  2692 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2693 to print the specified premise.  TermStyle.add_style provides an ML
  2694 interface for introducing further styles.  See also the "LaTeX Sugar"
  2695 document practical applications.  The ML antiquotation prints
  2696 type-checked ML expressions verbatim.
  2697 
  2698 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2699 and 'text' support optional locale specification '(in loc)', which
  2700 specifies the default context for interpreting antiquotations.  For
  2701 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2702 
  2703 * Option 'locale=NAME' of antiquotations specifies an alternative
  2704 context interpreting the subsequent argument.  For example: @{thm
  2705 [locale=lattice] inf_assoc}.
  2706 
  2707 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2708 a proof context.
  2709 
  2710 * Proper output of antiquotations for theory commands involving a
  2711 proof context (such as 'locale' or 'theorem (in loc) ...').
  2712 
  2713 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2714 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2715 
  2716 * isatool usedir: new option -C (default true) controls whether option
  2717 -D should include a copy of the original document directory; -C false
  2718 prevents unwanted effects such as copying of administrative CVS data.
  2719 
  2720 
  2721 *** Pure ***
  2722 
  2723 * Considerably improved version of 'constdefs' command.  Now performs
  2724 automatic type-inference of declared constants; additional support for
  2725 local structure declarations (cf. locales and HOL records), see also
  2726 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2727 sequential dependencies of definitions within a single 'constdefs'
  2728 section; moreover, the declared name needs to be an identifier.  If
  2729 all fails, consider to fall back on 'consts' and 'defs' separately.
  2730 
  2731 * Improved indexed syntax and implicit structures.  First of all,
  2732 indexed syntax provides a notational device for subscripted
  2733 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2734 expressions.  Secondly, in a local context with structure
  2735 declarations, number indexes \<^sub>n or the empty index (default
  2736 number 1) refer to a certain fixed variable implicitly; option
  2737 show_structs controls printing of implicit structures.  Typical
  2738 applications of these concepts involve record types and locales.
  2739 
  2740 * New command 'no_syntax' removes grammar declarations (and
  2741 translations) resulting from the given syntax specification, which is
  2742 interpreted in the same manner as for the 'syntax' command.
  2743 
  2744 * 'Advanced' translation functions (parse_translation etc.) may depend
  2745 on the signature of the theory context being presently used for
  2746 parsing/printing, see also isar-ref manual.
  2747 
  2748 * Improved 'oracle' command provides a type-safe interface to turn an
  2749 ML expression of type theory -> T -> term into a primitive rule of
  2750 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2751 is already included here); see also FOL/ex/IffExample.thy;
  2752 INCOMPATIBILITY.
  2753 
  2754 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2755 before); "cI" is no longer bound, use "c.intro" instead.
  2756 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2757 axclasses vs. locales.
  2758 
  2759 * Improved internal renaming of symbolic identifiers -- attach primes
  2760 instead of base 26 numbers.
  2761 
  2762 * New flag show_question_marks controls printing of leading question
  2763 marks in schematic variable names.
  2764 
  2765 * In schematic variable names, *any* symbol following \<^isub> or
  2766 \<^isup> is now treated as part of the base name.  For example, the
  2767 following works without printing of awkward ".0" indexes:
  2768 
  2769   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2770     by simp
  2771 
  2772 * Inner syntax includes (*(*nested*) comments*).
  2773 
  2774 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2775 annotations as "(00...)".
  2776 
  2777 * Clear separation of logical types and nonterminals, where the latter
  2778 may only occur in 'syntax' specifications or type abbreviations.
  2779 Before that distinction was only partially implemented via type class
  2780 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2781 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2782 exotic syntax specifications may require further adaption
  2783 (e.g. Cube/Cube.thy).
  2784 
  2785 * Removed obsolete type class "logic", use the top sort {} instead.
  2786 Note that non-logical types should be declared as 'nonterminals'
  2787 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2788 specifications.
  2789 
  2790 * Attributes 'induct' and 'cases': type or set names may now be
  2791 locally fixed variables as well.
  2792 
  2793 * Simplifier: can now control the depth to which conditional rewriting
  2794 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2795 Limit.
  2796 
  2797 * Simplifier: simplification procedures may now take the current
  2798 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2799 interface), which is very useful for calling the Simplifier
  2800 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2801 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2802 low-level mk_simproc no longer applies Logic.varify internally, to
  2803 allow for use in a context of fixed variables.
  2804 
  2805 * thin_tac now works even if the assumption being deleted contains !!
  2806 or ==>.  More generally, erule now works even if the major premise of
  2807 the elimination rule contains !! or ==>.
  2808 
  2809 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2810 
  2811 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2812 from Pure, which contains all common declarations already.  Both
  2813 theories are defined via plain Isabelle/Isar .thy files.
  2814 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2815 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2816 use isatool fixcpure to adapt your theory and ML sources.
  2817 
  2818 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2819 selections of theorems in named facts via index ranges.
  2820 
  2821 * 'print_theorems': in theory mode, really print the difference
  2822 wrt. the last state (works for interactive theory development only),
  2823 in proof mode print all local facts (cf. 'print_facts');
  2824 
  2825 * 'hide': option '(open)' hides only base names.
  2826 
  2827 * More efficient treatment of intermediate checkpoints in interactive
  2828 theory development.
  2829 
  2830 * Code generator is now invoked via code_module (incremental code
  2831 generation) and code_library (modular code generation, ML structures
  2832 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2833 must be quoted when used as identifiers.
  2834 
  2835 * New 'value' command for reading, evaluating and printing terms using
  2836 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2837 quoted when used as identifier.
  2838 
  2839 
  2840 *** Locales ***
  2841 
  2842 * New commands for the interpretation of locale expressions in
  2843 theories (1), locales (2) and proof contexts (3).  These generate
  2844 proof obligations from the expression specification.  After the
  2845 obligations have been discharged, theorems of the expression are added
  2846 to the theory, target locale or proof context.  The synopsis of the
  2847 commands is a follows:
  2848 
  2849   (1) interpretation expr inst
  2850   (2) interpretation target < expr
  2851   (3) interpret expr inst
  2852 
  2853 Interpretation in theories and proof contexts require a parameter
  2854 instantiation of terms from the current context.  This is applied to
  2855 specifications and theorems of the interpreted expression.
  2856 Interpretation in locales only permits parameter renaming through the
  2857 locale expression.  Interpretation is smart in that interpretations
  2858 that are active already do not occur in proof obligations, neither are
  2859 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2860 inspect active interpretations of a particular locale.  For details,
  2861 see the Isar Reference manual.  Examples can be found in
  2862 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2863 
  2864 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2865 'interpret' instead.
  2866 
  2867 * New context element 'constrains' for adding type constraints to
  2868 parameters.
  2869 
  2870 * Context expressions: renaming of parameters with syntax
  2871 redeclaration.
  2872 
  2873 * Locale declaration: 'includes' disallowed.
  2874 
  2875 * Proper static binding of attribute syntax -- i.e. types / terms /
  2876 facts mentioned as arguments are always those of the locale definition
  2877 context, independently of the context of later invocations.  Moreover,
  2878 locale operations (renaming and type / term instantiation) are applied
  2879 to attribute arguments as expected.
  2880 
  2881 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2882 actual attributes; rare situations may require Attrib.attribute to
  2883 embed those attributes into Attrib.src that lack concrete syntax.
  2884 Attribute implementations need to cooperate properly with the static
  2885 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2886 Attrib.XXX_thm etc. already do the right thing without further
  2887 intervention.  Only unusual applications -- such as "where" or "of"
  2888 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2889 on the context and the facts involved -- may have to assign parsed
  2890 values to argument tokens explicitly.
  2891 
  2892 * Changed parameter management in theorem generation for long goal
  2893 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2894 theorem statement in rare situations.
  2895 
  2896 * Locale inspection command 'print_locale' omits notes elements.  Use
  2897 'print_locale!' to have them included in the output.
  2898 
  2899 
  2900 *** Provers ***
  2901 
  2902 * Provers/hypsubst.ML: improved version of the subst method, for
  2903 single-step rewriting: it now works in bound variable contexts. New is
  2904 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2905 rewrite a different subterm than the original subst method, which is
  2906 still available as 'simplesubst'.
  2907 
  2908 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2909 and quasi orders.
  2910 
  2911 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2912 reflexive-transitive closure of relations.
  2913 
  2914 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2915 limit (previously hard-coded with a value of 20) user-definable.
  2916 
  2917 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2918 is peformed already.  Object-logics merely need to finish their
  2919 initial simpset configuration as before.  INCOMPATIBILITY.
  2920 
  2921 
  2922 *** HOL ***
  2923 
  2924 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2925 
  2926   syntax (epsilon)
  2927     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2928 
  2929 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2930 and x-symbol; use option '-m epsilon' to get it actually printed.
  2931 Moreover, the mathematically important symbolic identifier \<epsilon>
  2932 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2933 
  2934 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2935 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2936 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2937 support corresponding Isar calculations.
  2938 
  2939 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2940 instead of ":".
  2941 
  2942 * theory SetInterval: changed the syntax for open intervals:
  2943 
  2944   Old       New
  2945   {..n(}    {..<n}
  2946   {)n..}    {n<..}
  2947   {m..n(}   {m..<n}
  2948   {)m..n}   {m<..n}
  2949   {)m..n(}  {m<..<n}
  2950 
  2951 The old syntax is still supported but will disappear in the next
  2952 release.  For conversion use the following Emacs search and replace
  2953 patterns (these are not perfect but work quite well):
  2954 
  2955   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2956   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2957 
  2958 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2959 equalities in commutative rings; method 'algebra' provides a generic
  2960 interface.
  2961 
  2962 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2963 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2964 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2965 be a tuple pattern.
  2966 
  2967 Some new syntax forms are available:
  2968 
  2969   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2970   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2971   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2972   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2973 
  2974 The latter form "\<Sum>x < k. e" used to be based on a separate
  2975 function "Summation", which has been discontinued.
  2976 
  2977 * theory Finite_Set: in structured induction proofs, the insert case
  2978 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2979 (insert F x)'.
  2980 
  2981 * The 'refute' command has been extended to support a much larger
  2982 fragment of HOL, including axiomatic type classes, constdefs and
  2983 typedefs, inductive datatypes and recursion.
  2984 
  2985 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2986 Requires zChaff with proof generation to be installed.  See
  2987 HOL/ex/SAT_Examples.thy for examples.
  2988 
  2989 * Datatype induction via method 'induct' now preserves the name of the
  2990 induction variable. For example, when proving P(xs::'a list) by
  2991 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2992 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2993 in unstructured proof scripts.
  2994 
  2995 * Reworked implementation of records.  Improved scalability for
  2996 records with many fields, avoiding performance problems for type
  2997 inference. Records are no longer composed of nested field types, but
  2998 of nested extension types. Therefore the record type only grows linear
  2999 in the number of extensions and not in the number of fields.  The
  3000 top-level (users) view on records is preserved.  Potential
  3001 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3002 old record representation. The type generated for a record is called
  3003 <record_name>_ext_type.
  3004 
  3005 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3006 proofs triggered by a record definition or a simproc (if
  3007 quick_and_dirty is enabled).  Definitions of large records can take
  3008 quite long.
  3009 
  3010 New simproc record_upd_simproc for simplification of multiple record
  3011 updates enabled by default.  Moreover, trivial updates are also
  3012 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3013 occasionally, since simplification is more powerful by default.
  3014 
  3015 * typedef: proper support for polymorphic sets, which contain extra
  3016 type-variables in the term.
  3017 
  3018 * Simplifier: automatically reasons about transitivity chains
  3019 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3020 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3021 old proofs break occasionally as simplification may now solve more
  3022 goals than previously.
  3023 
  3024 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3025 present.  Works for all partial orders (class "order"), in particular
  3026 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3027 just like y <= x.
  3028 
  3029 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3030 bound variable or a constant then the let is unfolded.  Otherwise
  3031 first a is simplified to b, and then f b is simplified to g. If
  3032 possible we abstract b from g arriving at "let x = b in h x",
  3033 otherwise we unfold the let and arrive at g.  The simproc can be
  3034 enabled/disabled by the reference use_let_simproc.  Potential
  3035 INCOMPATIBILITY since simplification is more powerful by default.
  3036 
  3037 * Classical reasoning: the meson method now accepts theorems as arguments.
  3038 
  3039 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3040 jobs to provide advice on the provability of subgoals.
  3041 
  3042 * Theory OrderedGroup and Ring_and_Field: various additions and
  3043 improvements to faciliate calculations involving equalities and
  3044 inequalities.
  3045 
  3046 The following theorems have been eliminated or modified
  3047 (INCOMPATIBILITY):
  3048 
  3049   abs_eq             now named abs_of_nonneg
  3050   abs_of_ge_0        now named abs_of_nonneg
  3051   abs_minus_eq       now named abs_of_nonpos
  3052   imp_abs_id         now named abs_of_nonneg
  3053   imp_abs_neg_id     now named abs_of_nonpos
  3054   mult_pos           now named mult_pos_pos
  3055   mult_pos_le        now named mult_nonneg_nonneg
  3056   mult_pos_neg_le    now named mult_nonneg_nonpos
  3057   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3058   mult_neg           now named mult_neg_neg
  3059   mult_neg_le        now named mult_nonpos_nonpos
  3060 
  3061 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3062      
  3063      zero_le_square
  3064      not_square_less_zero 
  3065 
  3066   The following lemmas have been deleted from Real/RealPow:
  3067   
  3068      realpow_zero_zero
  3069      realpow_two
  3070      realpow_less
  3071      zero_le_power
  3072      realpow_two_le
  3073      abs_realpow_two
  3074      realpow_two_abs     
  3075 
  3076 * Theory Parity: added rules for simplifying exponents.
  3077 
  3078 * Theory List:
  3079 
  3080 The following theorems have been eliminated or modified
  3081 (INCOMPATIBILITY):
  3082 
  3083   list_all_Nil       now named list_all.simps(1)
  3084   list_all_Cons      now named list_all.simps(2)
  3085   list_all_conv      now named list_all_iff
  3086   set_mem_eq         now named mem_iff
  3087 
  3088 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3089 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3090 
  3091 
  3092 *** HOL-Complex ***
  3093 
  3094 * Theory RealDef: better support for embedding natural numbers and
  3095 integers in the reals.
  3096 
  3097 The following theorems have been eliminated or modified
  3098 (INCOMPATIBILITY):
  3099 
  3100   exp_ge_add_one_self  now requires no hypotheses
  3101   real_of_int_add      reversed direction of equality (use [symmetric])
  3102   real_of_int_minus    reversed direction of equality (use [symmetric])
  3103   real_of_int_diff     reversed direction of equality (use [symmetric])
  3104   real_of_int_mult     reversed direction of equality (use [symmetric])
  3105 
  3106 * Theory RComplete: expanded support for floor and ceiling functions.
  3107 
  3108 * Theory Ln is new, with properties of the natural logarithm
  3109 
  3110 * Hyperreal: There is a new type constructor "star" for making
  3111 nonstandard types.  The old type names are now type synonyms:
  3112 
  3113   hypreal = real star
  3114   hypnat = nat star
  3115   hcomplex = complex star
  3116 
  3117 * Hyperreal: Many groups of similarly-defined constants have been
  3118 replaced by polymorphic versions (INCOMPATIBILITY):
  3119 
  3120   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3121 
  3122   starset      <-- starsetNat, starsetC
  3123   *s*          <-- *sNat*, *sc*
  3124   starset_n    <-- starsetNat_n, starsetC_n
  3125   *sn*         <-- *sNatn*, *scn*
  3126   InternalSets <-- InternalNatSets, InternalCSets
  3127 
  3128   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3129   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3130   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3131   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3132   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3133 
  3134 * Hyperreal: Many type-specific theorems have been removed in favor of
  3135 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3136 
  3137   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3138   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3139   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3140   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3141   right_minus <-- hypreal_add_minus
  3142   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3143   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3144   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3145   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3146   mult_1_right <-- hcomplex_mult_one_right
  3147   mult_zero_left <-- hcomplex_mult_zero_left
  3148   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3149   right_distrib <-- hypnat_add_mult_distrib2
  3150   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3151   right_inverse <-- hypreal_mult_inverse
  3152   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3153   order_refl <-- {hypreal,hypnat}_le_refl
  3154   order_trans <-- {hypreal,hypnat}_le_trans
  3155   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3156   order_less_le <-- {hypreal,hypnat}_less_le
  3157   linorder_linear <-- {hypreal,hypnat}_le_linear
  3158   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3159   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3160   add_nonneg_nonneg <-- hypreal_le_add_order
  3161 
  3162 * Hyperreal: Separate theorems having to do with type-specific
  3163 versions of constants have been merged into theorems that apply to the
  3164 new polymorphic constants (INCOMPATIBILITY):
  3165 
  3166   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3167   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3168   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3169   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3170   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3171   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3172   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3173   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3174   STAR_diff <-- {STAR,STARC}_diff
  3175   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3176     STARC_hcomplex_of_complex}_image_subset
  3177   starset_n_Un <-- starset{Nat,C}_n_Un
  3178   starset_n_Int <-- starset{Nat,C}_n_Int
  3179   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3180   starset_n_diff <-- starset{Nat,C}_n_diff
  3181   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3182   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3183   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3184   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3185   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3186   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3187   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3188   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3189   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3190   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3191   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3192   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3193   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3194   starfun_diff <-- starfun{C,RC,CR}_diff
  3195   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3196   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3197   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3198   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3199   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3200   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3201   starfun_Id <-- starfunC_Id
  3202   starfun_approx <-- starfun{Nat,CR}_approx
  3203   starfun_capprox <-- starfun{C,RC}_capprox
  3204   starfun_abs <-- starfunNat_rabs
  3205   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3206   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3207   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3208   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3209   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3210   starfun_add_approx <-- starfunCR_add_approx
  3211   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3212   starfun_divide <-- starfun{C,CR,RC}_divide
  3213   starfun_n <-- starfun{Nat,C}_n
  3214   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3215   starfun_n_add <-- starfun{Nat,C}_n_add
  3216   starfun_n_add_minus <-- starfunNat_n_add_minus
  3217   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3218   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3219   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3220 
  3221   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3222   star_n_minus <-- {hypreal,hcomplex}_minus
  3223   star_n_diff <-- {hypreal,hcomplex}_diff
  3224   star_n_mult <-- {hypreal,hcomplex}_mult
  3225   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3226   star_n_le <-- {hypreal,hypnat}_le
  3227   star_n_less <-- {hypreal,hypnat}_less
  3228   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3229   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3230   star_n_abs <-- hypreal_hrabs
  3231   star_n_divide <-- hcomplex_divide
  3232 
  3233   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3234   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3235   star_of_diff <-- hypreal_of_real_diff
  3236   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3237   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3238   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3239   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3240   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3241   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3242   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3243   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3244   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3245   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3246   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3247   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3248   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3249   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3250   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3251   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3252   star_of_power <-- hypreal_of_real_power
  3253   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3254 
  3255 * Hyperreal: new method "transfer" that implements the transfer
  3256 principle of nonstandard analysis. With a subgoal that mentions
  3257 nonstandard types like "'a star", the command "apply transfer"
  3258 replaces it with an equivalent one that mentions only standard types.
  3259 To be successful, all free variables must have standard types; non-
  3260 standard variables must have explicit universal quantifiers.
  3261 
  3262 * Hyperreal: A theory of Taylor series.
  3263 
  3264 
  3265 *** HOLCF ***
  3266 
  3267 * Discontinued special version of 'constdefs' (which used to support
  3268 continuous functions) in favor of the general Pure one with full
  3269 type-inference.
  3270 
  3271 * New simplification procedure for solving continuity conditions; it
  3272 is much faster on terms with many nested lambda abstractions (cubic
  3273 instead of exponential time).
  3274 
  3275 * New syntax for domain package: selector names are now optional.
  3276 Parentheses should be omitted unless argument is lazy, for example:
  3277 
  3278   domain 'a stream = cons "'a" (lazy "'a stream")
  3279 
  3280 * New command 'fixrec' for defining recursive functions with pattern
  3281 matching; defining multiple functions with mutual recursion is also
  3282 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3283 sinr, or any data constructor defined by the domain package. The given
  3284 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3285 syntax and examples.
  3286 
  3287 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3288 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3289 but the proof obligation additionally includes an admissibility
  3290 requirement. The packages generate instances of class cpo or pcpo,
  3291 with continuity and strictness theorems for Rep and Abs.
  3292 
  3293 * HOLCF: Many theorems have been renamed according to a more standard naming
  3294 scheme (INCOMPATIBILITY):
  3295 
  3296   foo_inject:  "foo$x = foo$y ==> x = y"
  3297   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3298   foo_less:    "(foo$x << foo$y) = (x << y)"
  3299   foo_strict:  "foo$UU = UU"
  3300   foo_defined: "... ==> foo$x ~= UU"
  3301   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3302 
  3303 
  3304 *** ZF ***
  3305 
  3306 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3307 including the First Isomorphism Theorem (on quotienting by the kernel
  3308 of a homomorphism).
  3309 
  3310 * ZF/Simplifier: install second copy of type solver that actually
  3311 makes use of TC rules declared to Isar proof contexts (or locales);
  3312 the old version is still required for ML proof scripts.
  3313 
  3314 
  3315 *** Cube ***
  3316 
  3317 * Converted to Isar theory format; use locales instead of axiomatic
  3318 theories.
  3319 
  3320 
  3321 *** ML ***
  3322 
  3323 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3324 for ||>, ||>>, |>>,
  3325 
  3326 * Pure/library.ML no longer defines its own option datatype, but uses
  3327 that of the SML basis, which has constructors NONE and SOME instead of
  3328 None and Some, as well as exception Option.Option instead of OPTION.
  3329 The functions the, if_none, is_some, is_none have been adapted
  3330 accordingly, while Option.map replaces apsome.
  3331 
  3332 * Pure/library.ML: the exception LIST has been given up in favour of
  3333 the standard exceptions Empty and Subscript, as well as
  3334 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3335 superceded by the standard hd and tl functions etc.
  3336 
  3337 A number of basic list functions are no longer exported to the ML
  3338 toplevel, as they are variants of predefined functions.  The following
  3339 suggests how one can translate existing code:
  3340 
  3341     rev_append xs ys = List.revAppend (xs, ys)
  3342     nth_elem (i, xs) = List.nth (xs, i)
  3343     last_elem xs = List.last xs
  3344     flat xss = List.concat xss
  3345     seq fs = List.app fs
  3346     partition P xs = List.partition P xs
  3347     mapfilter f xs = List.mapPartial f xs
  3348 
  3349 * Pure/library.ML: several combinators for linear functional
  3350 transformations, notably reverse application and composition:
  3351 
  3352   x |> f                f #> g
  3353   (x, y) |-> f          f #-> g
  3354 
  3355 * Pure/library.ML: introduced/changed precedence of infix operators:
  3356 
  3357   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3358   infix 2 ?;
  3359   infix 3 o oo ooo oooo;
  3360   infix 4 ~~ upto downto;
  3361 
  3362 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3363 infix operators.
  3364 
  3365 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3366 fold_map support linear functional transformations and nesting.  For
  3367 example:
  3368 
  3369   fold f [x1, ..., xN] y =
  3370     y |> f x1 |> ... |> f xN
  3371 
  3372   (fold o fold) f [xs1, ..., xsN] y =
  3373     y |> fold f xs1 |> ... |> fold f xsN
  3374 
  3375   fold f [x1, ..., xN] =
  3376     f x1 #> ... #> f xN
  3377 
  3378   (fold o fold) f [xs1, ..., xsN] =
  3379     fold f xs1 #> ... #> fold f xsN
  3380 
  3381 * Pure/library.ML: the following selectors on type 'a option are
  3382 available:
  3383 
  3384   the:               'a option -> 'a  (*partial*)
  3385   these:             'a option -> 'a  where 'a = 'b list
  3386   the_default: 'a -> 'a option -> 'a
  3387   the_list:          'a option -> 'a list
  3388 
  3389 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3390 basic operations for association lists, following natural argument
  3391 order; moreover the explicit equality predicate passed here avoids
  3392 potentially expensive polymorphic runtime equality checks.
  3393 The old functions may be expressed as follows:
  3394 
  3395   assoc = uncurry (AList.lookup (op =))
  3396   assocs = these oo AList.lookup (op =)
  3397   overwrite = uncurry (AList.update (op =)) o swap
  3398 
  3399 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3400 
  3401   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3402   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3403 
  3404 replacing make_keylist and keyfilter (occassionally used)
  3405 Naive rewrites:
  3406 
  3407   make_keylist = AList.make
  3408   keyfilter = AList.find (op =)
  3409 
  3410 * eq_fst and eq_snd now take explicit equality parameter, thus
  3411   avoiding eqtypes. Naive rewrites:
  3412 
  3413     eq_fst = eq_fst (op =)
  3414     eq_snd = eq_snd (op =)
  3415 
  3416 * Removed deprecated apl and apr (rarely used).
  3417   Naive rewrites:
  3418 
  3419     apl (n, op) =>>= curry op n
  3420     apr (op, m) =>>= fn n => op (n, m)
  3421 
  3422 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3423 provides a reasonably efficient light-weight implementation of sets as
  3424 lists.
  3425 
  3426 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3427 few new operations; existing lookup and update are now curried to
  3428 follow natural argument order (for use with fold etc.);
  3429 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3430 
  3431 * Pure/General: output via the Isabelle channels of
  3432 writeln/warning/error etc. is now passed through Output.output, with a
  3433 hook for arbitrary transformations depending on the print_mode
  3434 (cf. Output.add_mode -- the first active mode that provides a output
  3435 function wins).  Already formatted output may be embedded into further
  3436 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3437 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3438 accommodate easy composition of diagnostic messages etc.  Programmers
  3439 rarely need to care about Output.output or Output.raw at all, with
  3440 some notable exceptions: Output.output is required when bypassing the
  3441 standard channels (writeln etc.), or in token translations to produce
  3442 properly formatted results; Output.raw is required when capturing
  3443 already output material that will eventually be presented to the user
  3444 a second time.  For the default print mode, both Output.output and
  3445 Output.raw have no effect.
  3446 
  3447 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3448 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3449 cumulative results are displayed at the end of a batch session.
  3450 
  3451 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3452 replaced by File.platform_path and File.shell_path (with appropriate
  3453 hooks).  This provides a clean interface for unusual systems where the
  3454 internal and external process view of file names are different.
  3455 
  3456 * Pure: more efficient orders for basic syntactic entities: added
  3457 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3458 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3459 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3460 orders now -- potential INCOMPATIBILITY for code that depends on a
  3461 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3462 Library.sort_strings on result).
  3463 
  3464 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3465 fold_types traverse types/terms from left to right, observing natural
  3466 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3467 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3468 
  3469 * Pure: name spaces have been refined, with significant changes of the
  3470 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3471 to extern(_table).  The plain name entry path is superceded by a
  3472 general 'naming' context, which also includes the 'policy' to produce
  3473 a fully qualified name and external accesses of a fully qualified
  3474 name; NameSpace.extend is superceded by context dependent
  3475 Sign.declare_name.  Several theory and proof context operations modify
  3476 the naming context.  Especially note Theory.restore_naming and
  3477 ProofContext.restore_naming to get back to a sane state; note that
  3478 Theory.add_path is no longer sufficient to recover from
  3479 Theory.absolute_path in particular.
  3480 
  3481 * Pure: new flags short_names (default false) and unique_names
  3482 (default true) for controlling output of qualified names.  If
  3483 short_names is set, names are printed unqualified.  If unique_names is
  3484 reset, the name prefix is reduced to the minimum required to achieve
  3485 the original result when interning again, even if there is an overlap
  3486 with earlier declarations.
  3487 
  3488 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3489 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3490 (useful for printing error messages).  INCOMPATIBILITY.
  3491 
  3492 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3493 Theory.theory are now identified, referring to the universal
  3494 Context.theory (see Pure/context.ML).  Actual signature and theory
  3495 content is managed as theory data.  The old code and interfaces were
  3496 spread over many files and structures; the new arrangement introduces
  3497 considerable INCOMPATIBILITY to gain more clarity:
  3498 
  3499   Context -- theory management operations (name, identity, inclusion,
  3500     parents, ancestors, merge, etc.), plus generic theory data;
  3501 
  3502   Sign -- logical signature and syntax operations (declaring consts,
  3503     types, etc.), plus certify/read for common entities;
  3504 
  3505   Theory -- logical theory operations (stating axioms, definitions,
  3506     oracles), plus a copy of logical signature operations (consts,
  3507     types, etc.); also a few basic management operations (Theory.copy,
  3508     Theory.merge, etc.)
  3509 
  3510 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3511 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3512 for convenience -- they merely return the theory.
  3513 
  3514 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3515 
  3516 * Pure: the Isar proof context type is already defined early in Pure
  3517 as Context.proof (note that ProofContext.context and Proof.context are
  3518 aliases, where the latter is the preferred name).  This enables other
  3519 Isabelle components to refer to that type even before Isar is present.
  3520 
  3521 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3522 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3523 any of these kinds.  For example, Sign.intern typeK is now
  3524 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3525 Theory.hide_types.  Also note that former
  3526 Theory.hide_classes/types/consts are now
  3527 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3528 internalize their arguments!  INCOMPATIBILITY.
  3529 
  3530 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3531 datatype thmref (with constructors Name and NameSelection) instead of
  3532 plain string -- INCOMPATIBILITY;
  3533 
  3534 * Pure: cases produced by proof methods specify options, where NONE
  3535 means to remove case bindings -- INCOMPATIBILITY in
  3536 (RAW_)METHOD_CASES.
  3537 
  3538 * Pure: the following operations retrieve axioms or theorems from a
  3539 theory node or theory hierarchy, respectively:
  3540 
  3541   Theory.axioms_of: theory -> (string * term) list
  3542   Theory.all_axioms_of: theory -> (string * term) list
  3543   PureThy.thms_of: theory -> (string * thm) list
  3544   PureThy.all_thms_of: theory -> (string * thm) list
  3545 
  3546 * Pure: print_tac now outputs the goal through the trace channel.
  3547 
  3548 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3549 Reference Toplevel.debug (default false) controls detailed printing
  3550 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3551 controls execution profiling -- set to 1 for time and 2 for space
  3552 (both increase the runtime).
  3553 
  3554 * Isar session: The initial use of ROOT.ML is now always timed,
  3555 i.e. the log will show the actual process times, in contrast to the
  3556 elapsed wall-clock time that the outer shell wrapper produces.
  3557 
  3558 * Simplifier: improved handling of bound variables (nameless
  3559 representation, avoid allocating new strings).  Simprocs that invoke
  3560 the Simplifier recursively should use Simplifier.inherit_bounds to
  3561 avoid local name clashes.  Failure to do so produces warnings
  3562 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3563 for further details.
  3564 
  3565 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3566 bindings for all theorems stored within a given theory; this may help
  3567 in porting non-Isar theories to Isar ones, while keeping ML proof
  3568 scripts for the time being.
  3569 
  3570 * ML operator HTML.with_charset specifies the charset begin used for
  3571 generated HTML files.  For example:
  3572 
  3573   HTML.with_charset "utf-8" use_thy "Hebrew";
  3574   HTML.with_charset "utf-8" use_thy "Chinese";
  3575 
  3576 
  3577 *** System ***
  3578 
  3579 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3580 isabelle, isatool etc.).
  3581 
  3582 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3583 isatool doc, isatool mkdir, display_drafts etc.).
  3584 
  3585 * isatool usedir: option -f allows specification of the ML file to be
  3586 used by Isabelle; default is ROOT.ML.
  3587 
  3588 * New isatool version outputs the version identifier of the Isabelle
  3589 distribution being used.
  3590 
  3591 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3592 (containing Boolean satisfiability problems) into Isabelle/HOL
  3593 theories.
  3594 
  3595 
  3596 
  3597 New in Isabelle2004 (April 2004)
  3598 --------------------------------
  3599 
  3600 *** General ***
  3601 
  3602 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3603   Replaces linorder.ML.
  3604 
  3605 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3606   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3607   (\<a>...\<z>), are now considered normal letters, and can therefore
  3608   be used anywhere where an ASCII letter (a...zA...Z) has until
  3609   now. COMPATIBILITY: This obviously changes the parsing of some
  3610   terms, especially where a symbol has been used as a binder, say
  3611   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3612   as an identifier.  Fix it by inserting a space around former
  3613   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3614   existing theory and ML files.
  3615 
  3616 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3617 
  3618 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3619   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3620   a normal (but invisible) letter. For multiple letter subscripts repeat
  3621   \<^isub> like this: x\<^isub>1\<^isub>2.
  3622 
  3623 * Pure: There are now sub-/superscripts that can span more than one
  3624   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3625   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3626   superscript. The new control characters are not identifier parts.
  3627 
  3628 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3629   content of "..." to the latex file instead of \isacntrl... . The "..."
  3630   may consist of any printable characters excluding the end bracket >.
  3631 
  3632 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3633   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3634   declare constants "final", which prevents their being given a definition
  3635   later.  It is useful for constants whose behaviour is fixed axiomatically
  3636   rather than definitionally, such as the meta-logic connectives.
  3637 
  3638 * Pure: 'instance' now handles general arities with general sorts
  3639   (i.e. intersections of classes),
  3640 
  3641 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3642   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3643   It can be changed to alter the colors/layout of generated pages.
  3644 
  3645 
  3646 *** Isar ***
  3647 
  3648 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3649   cut_tac, subgoal_tac and thin_tac:
  3650   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3651     locales are no longer forced to write Isar proof scripts.
  3652     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3653     emulations.
  3654   - INCOMPATIBILITY: names of variables to be instantiated may no
  3655     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3656     This is consistent with the instantiation attribute "where".
  3657 
  3658 * Attributes "where" and "of":
  3659   - Now take type variables of instantiated theorem into account when reading
  3660     the instantiation string.  This fixes a bug that caused instantiated
  3661     theorems to have too special types in some circumstances.
  3662   - "where" permits explicit instantiations of type variables.
  3663 
  3664 * Calculation commands "moreover" and "also" no longer interfere with
  3665   current facts ("this"), admitting arbitrary combinations with "then"
  3666   and derived forms.
  3667 
  3668 * Locales:
  3669   - Goal statements involving the context element "includes" no longer
  3670     generate theorems with internal delta predicates (those ending on
  3671     "_axioms") in the premise.
  3672     Resolve particular premise with <locale>.intro to obtain old form.
  3673   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3674     specification and "includes" elements in goal statement.
  3675   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3676     [intro?] and [elim?] (respectively) by default.
  3677   - Experimental command for instantiation of locales in proof contexts:
  3678         instantiate <label>[<attrs>]: <loc>
  3679     Instantiates locale <loc> and adds all its theorems to the current context
  3680     taking into account their attributes.  Label and attrs are optional
  3681     modifiers, like in theorem declarations.  If present, names of
  3682     instantiated theorems are qualified with <label>, and the attributes
  3683     <attrs> are applied after any attributes these theorems might have already.
  3684       If the locale has assumptions, a chained fact of the form
  3685     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3686     are derived.  The command does not support old-style locales declared
  3687     with "locale (open)".
  3688       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3689 
  3690 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3691   (Isar) contexts.
  3692 
  3693 
  3694 *** HOL ***
  3695 
  3696 * Proof import: new image HOL4 contains the imported library from
  3697   the HOL4 system with about 2500 theorems. It is imported by
  3698   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3699   can be used like any other Isabelle image.  See
  3700   HOL/Import/HOL/README for more information.
  3701 
  3702 * Simplifier:
  3703   - Much improved handling of linear and partial orders.
  3704     Reasoners for linear and partial orders are set up for type classes
  3705     "linorder" and "order" respectively, and are added to the default simpset
  3706     as solvers.  This means that the simplifier can build transitivity chains
  3707     to solve goals from the assumptions.
  3708   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3709     of blast or auto after simplification become unnecessary because the goal
  3710     is solved by simplification already.
  3711 
  3712 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3713     all proved in axiomatic type classes for semirings, rings and fields.
  3714 
  3715 * Numerics:
  3716   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3717     now formalized using the Ring_and_Field theory mentioned above.
  3718   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3719     than before, because now they are set up once in a generic manner.
  3720   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3721     Look for the general versions in Ring_and_Field (and Power if they concern
  3722     exponentiation).
  3723 
  3724 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3725 
  3726 * Records:
  3727   - Record types are now by default printed with their type abbreviation
  3728     instead of the list of all field types. This can be configured via
  3729     the reference "print_record_type_abbr".
  3730   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3731     (not enabled by default).
  3732   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3733     EX x. x = sel r to True (not enabled by default).
  3734   - Tactic "record_split_simp_tac" to split and simplify records added.
  3735 
  3736 * 'specification' command added, allowing for definition by
  3737   specification.  There is also an 'ax_specification' command that
  3738   introduces the new constants axiomatically.
  3739 
  3740 * arith(_tac) is now able to generate counterexamples for reals as well.
  3741 
  3742 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3743 
  3744 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3745   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3746 
  3747 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3748   matrix theory to linear programming.
  3749 
  3750 * Unions and Intersections:
  3751   The latex output syntax of UN and INT has been changed
  3752   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3753   i.e. the index formulae has become a subscript.
  3754   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3755 
  3756 * Unions and Intersections over Intervals:
  3757   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3758   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3759   like in normal math, and corresponding versions for < and for intersection.
  3760 
  3761 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3762   lexicographic dictonary ordering has been added as "lexord".
  3763 
  3764 * ML: the legacy theory structures Int and List have been removed. They had
  3765   conflicted with ML Basis Library structures having the same names.
  3766 
  3767 * 'refute' command added to search for (finite) countermodels.  Only works
  3768   for a fragment of HOL.  The installation of an external SAT solver is
  3769   highly recommended.  See "HOL/Refute.thy" for details.
  3770 
  3771 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3772   formulae under an assignment of free variables to random values.
  3773   In contrast to 'refute', it can deal with inductive datatypes,
  3774   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3775   for examples.
  3776 
  3777 
  3778 *** HOLCF ***
  3779 
  3780 * Streams now come with concatenation and are part of the HOLCF image
  3781 
  3782 
  3783 
  3784 New in Isabelle2003 (May 2003)
  3785 ------------------------------
  3786 
  3787 *** General ***
  3788 
  3789 * Provers/simplifier:
  3790 
  3791   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3792     Assumptions are now subject to complete mutual simplification,
  3793     not just from left to right. The simplifier now preserves
  3794     the order of assumptions.
  3795 
  3796     Potential INCOMPATIBILITY:
  3797 
  3798     -- simp sometimes diverges where the old version did
  3799        not, e.g. invoking simp on the goal
  3800 
  3801         [| P (f x); y = x; f x = f y |] ==> Q
  3802 
  3803        now gives rise to the infinite reduction sequence
  3804 
  3805         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3806 
  3807        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3808        kind of problem.
  3809 
  3810     -- Tactics combining classical reasoner and simplification (such as auto)
  3811        are also affected by this change, because many of them rely on
  3812        simp. They may sometimes diverge as well or yield a different numbers
  3813        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3814        in case of problems. Sometimes subsequent calls to the classical
  3815        reasoner will fail because a preceeding call to the simplifier too
  3816        eagerly simplified the goal, e.g. deleted redundant premises.
  3817 
  3818   - The simplifier trace now shows the names of the applied rewrite rules
  3819 
  3820   - You can limit the number of recursive invocations of the simplifier
  3821     during conditional rewriting (where the simplifie tries to solve the
  3822     conditions before applying the rewrite rule):
  3823     ML "simp_depth_limit := n"
  3824     where n is an integer. Thus you can force termination where previously
  3825     the simplifier would diverge.
  3826 
  3827   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3828 
  3829   - No longer aborts on failed congruence proof.  Instead, the
  3830     congruence is ignored.
  3831 
  3832 * Pure: New generic framework for extracting programs from constructive
  3833   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3834   as HOL/Extraction for some case studies.
  3835 
  3836 * Pure: The main goal of the proof state is no longer shown by default, only
  3837 the subgoals. This behaviour is controlled by a new flag.
  3838    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3839 (ML: Proof.show_main_goal).
  3840 
  3841 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3842 rules whose conclusion matches subgoal 1:
  3843       PG menu: Isabelle/Isar -> Show me -> matching rules
  3844 The rules are ordered by how closely they match the subgoal.
  3845 In particular, rules that solve a subgoal outright are displayed first
  3846 (or rather last, the way they are printed).
  3847 (ML: ProofGeneral.print_intros())
  3848 
  3849 * Pure: New flag trace_unify_fail causes unification to print
  3850 diagnostic information (PG: in trace buffer) when it fails. This is
  3851 useful for figuring out why single step proofs like rule, erule or
  3852 assumption failed.
  3853 
  3854 * Pure: Locale specifications now produce predicate definitions
  3855 according to the body of text (covering assumptions modulo local
  3856 definitions); predicate "loc_axioms" covers newly introduced text,
  3857 while "loc" is cumulative wrt. all included locale expressions; the
  3858 latter view is presented only on export into the global theory
  3859 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3860 on the old view without predicates;
  3861 
  3862 * Pure: predefined locales "var" and "struct" are useful for sharing
  3863 parameters (as in CASL, for example); just specify something like
  3864 ``var x + var y + struct M'' as import;
  3865 
  3866 * Pure: improved thms_containing: proper indexing of facts instead of
  3867 raw theorems; check validity of results wrt. current name space;
  3868 include local facts of proof configuration (also covers active
  3869 locales), cover fixed variables in index; may use "_" in term
  3870 specification; an optional limit for the number of printed facts may
  3871 be given (the default is 40);
  3872 
  3873 * Pure: disallow duplicate fact bindings within new-style theory files
  3874 (batch-mode only);
  3875 
  3876 * Provers: improved induct method: assumptions introduced by case
  3877 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3878 the goal statement); "foo" still refers to all facts collectively;
  3879 
  3880 * Provers: the function blast.overloaded has been removed: all constants
  3881 are regarded as potentially overloaded, which improves robustness in exchange
  3882 for slight decrease in efficiency;
  3883 
  3884 * Provers/linorder: New generic prover for transitivity reasoning over
  3885 linear orders.  Note: this prover is not efficient!
  3886 
  3887 * Isar: preview of problems to finish 'show' now produce an error
  3888 rather than just a warning (in interactive mode);
  3889 
  3890 
  3891 *** HOL ***
  3892 
  3893 * arith(_tac)
  3894 
  3895  - Produces a counter example if it cannot prove a goal.
  3896    Note that the counter example may be spurious if the goal is not a formula
  3897    of quantifier-free linear arithmetic.
  3898    In ProofGeneral the counter example appears in the trace buffer.
  3899 
  3900  - Knows about div k and mod k where k is a numeral of type nat or int.
  3901 
  3902  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3903    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3904    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3905 
  3906 * simp's arithmetic capabilities have been enhanced a bit: it now
  3907 takes ~= in premises into account (by performing a case split);
  3908 
  3909 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3910 are distributed over a sum of terms;
  3911 
  3912 * New tactic "trans_tac" and method "trans" instantiate
  3913 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3914 "<=", "<" and "=").
  3915 
  3916 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3917 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3918 
  3919 * 'typedef' command has new option "open" to suppress the set
  3920 definition;
  3921 
  3922 * functions Min and Max on finite sets have been introduced (theory
  3923 Finite_Set);
  3924 
  3925 * attribute [symmetric] now works for relations as well; it turns
  3926 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3927 
  3928 * induct over a !!-quantified statement (say !!x1..xn):
  3929   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3930 
  3931 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3932 %x. None. Warning: empty_def now refers to the previously hidden definition
  3933 of the empty set.
  3934 
  3935 * Algebra: formalization of classical algebra.  Intended as base for
  3936 any algebraic development in Isabelle.  Currently covers group theory
  3937 (up to Sylow's theorem) and ring theory (Universal Property of
  3938 Univariate Polynomials).  Contributions welcome;
  3939 
  3940 * GroupTheory: deleted, since its material has been moved to Algebra;
  3941 
  3942 * Complex: new directory of the complex numbers with numeric constants,
  3943 nonstandard complex numbers, and some complex analysis, standard and
  3944 nonstandard (Jacques Fleuriot);
  3945 
  3946 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3947 
  3948 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3949 Fleuriot);
  3950 
  3951 * Real/HahnBanach: updated and adapted to locales;
  3952 
  3953 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3954 Gray and Kramer);
  3955 
  3956 * UNITY: added the Meier-Sanders theory of progress sets;
  3957 
  3958 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3959 as abstract algorithms, instantiated to the JVM;
  3960 
  3961 * Bali: Java source language formalization. Type system, operational
  3962 semantics, axiomatic semantics. Supported language features:
  3963 classes, interfaces, objects,virtual methods, static methods,
  3964 static/instance fields, arrays, access modifiers, definite
  3965 assignment, exceptions.
  3966 
  3967 
  3968 *** ZF ***
  3969 
  3970 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3971 universe, etc.);
  3972 
  3973 * Main ZF: virtually all theories converted to new-style format;
  3974 
  3975 
  3976 *** ML ***
  3977 
  3978 * Pure: Tactic.prove provides sane interface for internal proofs;
  3979 omits the infamous "standard" operation, so this is more appropriate
  3980 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3981 
  3982 * Pure: improved error reporting of simprocs;
  3983 
  3984 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3985 up simprocs;
  3986 
  3987 
  3988 *** Document preparation ***
  3989 
  3990 * uses \par instead of \\ for line breaks in theory text. This may
  3991 shift some page breaks in large documents. To get the old behaviour
  3992 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3993 
  3994 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3995 other packages
  3996 
  3997 * \<euro> now needs package babel/greek instead of marvosym (which
  3998 broke \Rightarrow)
  3999 
  4000 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4001 textcomp package)
  4002 
  4003 
  4004 
  4005 New in Isabelle2002 (March 2002)
  4006 --------------------------------
  4007 
  4008 *** Document preparation ***
  4009 
  4010 * greatly simplified document preparation setup, including more
  4011 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4012 instructive isatool mkdir; users should basically be able to get
  4013 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4014 users may run a separate document processing stage manually like this:
  4015 "isatool usedir -D output HOL Test && isatool document Test/output";
  4016 
  4017 * theory dependency graph may now be incorporated into documents;
  4018 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4019 with \includegraphics of LaTeX;
  4020 
  4021 * proper spacing of consecutive markup elements, especially text
  4022 blocks after section headings;
  4023 
  4024 * support bold style (for single symbols only), input syntax is like
  4025 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4026 
  4027 * \<bullet> is now output as bold \cdot by default, which looks much
  4028 better in printed text;
  4029 
  4030 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4031 note that these symbols are currently unavailable in Proof General /
  4032 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4033 
  4034 * isatool latex no longer depends on changed TEXINPUTS, instead
  4035 isatool document copies the Isabelle style files to the target
  4036 location;
  4037 
  4038 
  4039 *** Isar ***
  4040 
  4041 * Pure/Provers: improved proof by cases and induction;
  4042   - 'case' command admits impromptu naming of parameters (such as
  4043     "case (Suc n)");
  4044   - 'induct' method divinates rule instantiation from the inductive
  4045     claim; no longer requires excessive ?P bindings for proper
  4046     instantiation of cases;
  4047   - 'induct' method properly enumerates all possibilities of set/type
  4048     rules; as a consequence facts may be also passed through *type*
  4049     rules without further ado;
  4050   - 'induct' method now derives symbolic cases from the *rulified*
  4051     rule (before it used to rulify cases stemming from the internal
  4052     atomized version); this means that the context of a non-atomic
  4053     statement becomes is included in the hypothesis, avoiding the
  4054     slightly cumbersome show "PROP ?case" form;
  4055   - 'induct' may now use elim-style induction rules without chaining
  4056     facts, using ``missing'' premises from the goal state; this allows
  4057     rules stemming from inductive sets to be applied in unstructured
  4058     scripts, while still benefitting from proper handling of non-atomic
  4059     statements; NB: major inductive premises need to be put first, all
  4060     the rest of the goal is passed through the induction;
  4061   - 'induct' proper support for mutual induction involving non-atomic
  4062     rule statements (uses the new concept of simultaneous goals, see
  4063     below);
  4064   - append all possible rule selections, but only use the first
  4065     success (no backtracking);
  4066   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4067   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4068   - added 'print_induct_rules' (covered by help item in recent Proof
  4069     General versions);
  4070   - moved induct/cases attributes to Pure, methods to Provers;
  4071   - generic method setup instantiated for FOL and HOL;
  4072 
  4073 * Pure: support multiple simultaneous goal statements, for example
  4074 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4075 meta-level mechanism, this acts as if several individual goals had
  4076 been stated separately; in particular common proof methods need to be
  4077 repeated in order to cover all claims; note that a single elimination
  4078 step is *not* sufficient to establish the two conjunctions, so this
  4079 fails:
  4080 
  4081   assume "A & B" then have A and B ..   (*".." fails*)
  4082 
  4083 better use "obtain" in situations as above; alternative refer to
  4084 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4085 
  4086 * Pure: proper integration with ``locales''; unlike the original
  4087 version by Florian Kammller, Isar locales package high-level proof
  4088 contexts rather than raw logical ones (e.g. we admit to include
  4089 attributes everywhere); operations on locales include merge and
  4090 rename; support for implicit arguments (``structures''); simultaneous
  4091 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4092 some examples;
  4093 
  4094 * Pure: the following commands have been ``localized'', supporting a
  4095 target locale specification "(in name)": 'lemma', 'theorem',
  4096 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4097 stored both within the locale and at the theory level (exported and
  4098 qualified by the locale name);
  4099 
  4100 * Pure: theory goals may now be specified in ``long'' form, with
  4101 ad-hoc contexts consisting of arbitrary locale elements. for example
  4102 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4103 definitions may be given, too); the result is a meta-level rule with
  4104 the context elements being discharged in the obvious way;
  4105 
  4106 * Pure: new proof command 'using' allows to augment currently used
  4107 facts after a goal statement ('using' is syntactically analogous to
  4108 'apply', but acts on the goal's facts only); this allows chained facts
  4109 to be separated into parts given before and after a claim, as in
  4110 ``from a and b have C using d and e <proof>'';
  4111 
  4112 * Pure: renamed "antecedent" case to "rule_context";
  4113 
  4114 * Pure: new 'judgment' command records explicit information about the
  4115 object-logic embedding (used by several tools internally); no longer
  4116 use hard-wired "Trueprop";
  4117 
  4118 * Pure: added 'corollary' command;
  4119 
  4120 * Pure: fixed 'token_translation' command;
  4121 
  4122 * Pure: removed obsolete 'exported' attribute;
  4123 
  4124 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4125 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4126 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4127 
  4128 * Pure: method 'atomize' presents local goal premises as object-level
  4129 statements (atomic meta-level propositions); setup controlled via
  4130 rewrite rules declarations of 'atomize' attribute; example
  4131 application: 'induct' method with proper rule statements in improper
  4132 proof *scripts*;
  4133 
  4134 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4135 now consider the syntactic context of assumptions, giving a better
  4136 chance to get type-inference of the arguments right (this is
  4137 especially important for locales);
  4138 
  4139 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4140 mode;
  4141 
  4142 * Pure/obtain: the formal conclusion "thesis", being marked as
  4143 ``internal'', may no longer be reference directly in the text;
  4144 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4145 situations;
  4146 
  4147 * Pure: generic 'sym' attribute which declares a rule both as pure
  4148 'elim?' and for the 'symmetric' operation;
  4149 
  4150 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4151 text; the fixed correlation with particular command syntax has been
  4152 discontinued;
  4153 
  4154 * Pure: new method 'rules' is particularly well-suited for proof
  4155 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4156 but often produces more compact proof terms with less detours;
  4157 
  4158 * Pure/Provers/classical: simplified integration with pure rule
  4159 attributes and methods; the classical "intro?/elim?/dest?"
  4160 declarations coincide with the pure ones; the "rule" method no longer
  4161 includes classically swapped intros; "intro" and "elim" methods no
  4162 longer pick rules from the context; also got rid of ML declarations
  4163 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4164 INCOMPATIBILITY;
  4165 
  4166 * Provers/classical: attribute 'swapped' produces classical inversions
  4167 of introduction rules;
  4168 
  4169 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4170 rules instead of full simplifier context; 'iff' attribute handles
  4171 conditional rules;
  4172 
  4173 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4174 
  4175 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4176 "(permissive)" option to recover old behavior;
  4177 
  4178 * HOL: 'inductive' no longer features separate (collective) attributes
  4179 for 'intros' (was found too confusing);
  4180 
  4181 * HOL: properly declared induction rules less_induct and
  4182 wf_induct_rule;
  4183 
  4184 
  4185 *** HOL ***
  4186 
  4187 * HOL: moved over to sane numeral syntax; the new policy is as
  4188 follows:
  4189 
  4190   - 0 and 1 are polymorphic constants, which are defined on any
  4191   numeric type (nat, int, real etc.);
  4192 
  4193   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4194   binary representation internally;
  4195 
  4196   - type nat has special constructor Suc, and generally prefers Suc 0
  4197   over 1::nat and Suc (Suc 0) over 2::nat;
  4198 
  4199 This change may cause significant problems of INCOMPATIBILITY; here
  4200 are some hints on converting existing sources:
  4201 
  4202   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4203   entities, so expressions involving "-" (unary or binary minus) need
  4204   to be spaced properly;
  4205 
  4206   - existing occurrences of "1" may need to be constraint "1::nat" or
  4207   even replaced by Suc 0; similar for old "2";
  4208 
  4209   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4210 
  4211   - remove all special provisions on numerals in proofs;
  4212 
  4213 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4214 representation (depends on bin_arith_simps in the default context);
  4215 
  4216 * HOL: symbolic syntax for x^2 (numeral 2);
  4217 
  4218 * HOL: the class of all HOL types is now called "type" rather than
  4219 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4220 in axclass/classes, instance/arities, and (usually rare) occurrences
  4221 in typings (of consts etc.); internally the class is called
  4222 "HOL.type", ML programs should refer to HOLogic.typeS;
  4223 
  4224 * HOL/record package improvements:
  4225   - new derived operations "fields" to build a partial record section,
  4226     "extend" to promote a fixed record to a record scheme, and
  4227     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4228     declared as simp by default;
  4229   - shared operations ("more", "fields", etc.) now need to be always
  4230     qualified) --- potential INCOMPATIBILITY;
  4231   - removed "make_scheme" operations (use "make" with "extend") --
  4232     INCOMPATIBILITY;
  4233   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4234   - provides cases/induct rules for use with corresponding Isar
  4235     methods (for concrete records, record schemes, concrete more
  4236     parts, and schematic more parts -- in that order);
  4237   - internal definitions directly based on a light-weight abstract
  4238     theory of product types over typedef rather than datatype;
  4239 
  4240 * HOL: generic code generator for generating executable ML code from
  4241 specifications; specific support for HOL constructs such as inductive
  4242 datatypes and sets, as well as recursive functions; can be invoked
  4243 via 'generate_code' theory section;
  4244 
  4245 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4246 
  4247 * HOL: consolidated and renamed several theories.  In particular:
  4248         Ord.thy has been absorbed into HOL.thy
  4249         String.thy has been absorbed into List.thy
  4250 
  4251 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4252 (beware of argument permutation!);
  4253 
  4254 * HOL: linorder_less_split superseded by linorder_cases;
  4255 
  4256 * HOL/List: "nodups" renamed to "distinct";
  4257 
  4258 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4259 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4260   - Ex_def has changed, now need to use some_eq_ex
  4261 
  4262 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4263 in this (rare) case use:
  4264 
  4265   delSWrapper "split_all_tac"
  4266   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4267 
  4268 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4269 MAY FAIL;
  4270 
  4271 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4272 Isabelle's type classes, ^ on functions and relations has too general
  4273 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4274 necessary to attach explicit type constraints;
  4275 
  4276 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4277 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4278 renamed accordingly (eg "compI" -> "rel_compI").
  4279 
  4280 * HOL: syntax translations now work properly with numerals and records
  4281 expressions;
  4282 
  4283 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4284 of "lam" -- INCOMPATIBILITY;
  4285 
  4286 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4287 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4288 renamed "Product_Type.unit";
  4289 
  4290 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4291 
  4292 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4293 the "cases" method);
  4294 
  4295 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4296 Florian Kammller);
  4297 
  4298 * HOL/IMP: updated and converted to new-style theory format; several
  4299 parts turned into readable document, with proper Isar proof texts and
  4300 some explanations (by Gerwin Klein);
  4301 
  4302 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4303 
  4304 * HOL-Hyperreal is now a logic image;
  4305 
  4306 
  4307 *** HOLCF ***
  4308 
  4309 * Isar: consts/constdefs supports mixfix syntax for continuous
  4310 operations;
  4311 
  4312 * Isar: domain package adapted to new-style theory format, e.g. see
  4313 HOLCF/ex/Dnat.thy;
  4314 
  4315 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4316 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4317 lift.induct_tac, always use UU instead of Undef;
  4318 
  4319 * HOLCF/IMP: updated and converted to new-style theory;
  4320 
  4321 
  4322 *** ZF ***
  4323 
  4324 * Isar: proper integration of logic-specific tools and packages,
  4325 including theory commands '(co)inductive', '(co)datatype',
  4326 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4327 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4328 
  4329 * theory Main no longer includes AC; for the Axiom of Choice, base
  4330 your theory on Main_ZFC;
  4331 
  4332 * the integer library now covers quotients and remainders, with many
  4333 laws relating division to addition, multiplication, etc.;
  4334 
  4335 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4336 typeless version of the formalism;
  4337 
  4338 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4339 format;
  4340 
  4341 * ZF/Induct: new directory for examples of inductive definitions,
  4342 including theory Multiset for multiset orderings; converted to
  4343 new-style theory format;
  4344 
  4345 * ZF: many new theorems about lists, ordinals, etc.;
  4346 
  4347 
  4348 *** General ***
  4349 
  4350 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4351 variable proof controls level of detail: 0 = no proofs (only oracle
  4352 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4353 also ref manual for further ML interfaces;
  4354 
  4355 * Pure/axclass: removed obsolete ML interface
  4356 goal_subclass/goal_arity;
  4357 
  4358 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4359 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4360 separate tokens, so expressions involving minus need to be spaced
  4361 properly;
  4362 
  4363 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4364 rather than "infixl" or "infixr";
  4365 
  4366 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4367 sort constraint specifications in type inference; e.g. "x::_::foo"
  4368 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4369 type variable);
  4370 
  4371 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4372 control output of nested => (types); the default behavior is
  4373 "type_brackets";
  4374 
  4375 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4376 tokens into AST constants;
  4377 
  4378 * Pure/syntax: prefer later declarations of translations and print
  4379 translation functions; potential INCOMPATIBILITY: need to reverse
  4380 multiple declarations for same syntax element constant;
  4381 
  4382 * Pure/show_hyps reset by default (in accordance to existing Isar
  4383 practice);
  4384 
  4385 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4386 addSafter;
  4387 
  4388 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4389 as well;
  4390 
  4391 * system: tested support for MacOS X; should be able to get Isabelle +
  4392 Proof General to work in a plain Terminal after installing Poly/ML
  4393 (e.g. from the Isabelle distribution area) and GNU bash alone
  4394 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4395 support requires further installations, e.g. from
  4396 http://fink.sourceforge.net/);
  4397 
  4398 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4399 
  4400 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4401 of 40 MB), cf. ML_OPTIONS;
  4402 
  4403 * system: Proof General keywords specification is now part of the
  4404 Isabelle distribution (see etc/isar-keywords.el);
  4405 
  4406 * system: support for persistent Proof General sessions (refrain from
  4407 outdating all loaded theories on startup); user may create writable
  4408 logic images like this: ``isabelle -q HOL Test'';
  4409 
  4410 * system: smart selection of Isabelle process versus Isabelle
  4411 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4412 run both "isabelle" and "Isabelle" even if file names are badly
  4413 damaged (executable inspects the case of the first letter of its own
  4414 name); added separate "isabelle-process" and "isabelle-interface";
  4415 
  4416 * system: refrain from any attempt at filtering input streams; no
  4417 longer support ``8bit'' encoding of old isabelle font, instead proper
  4418 iso-latin characters may now be used; the related isatools
  4419 "symbolinput" and "nonascii" have disappeared as well;
  4420 
  4421 * system: removed old "xterm" interface (the print modes "xterm" and
  4422 "xterm_color" are still available for direct use in a suitable
  4423 terminal);
  4424 
  4425 
  4426 
  4427 New in Isabelle99-2 (February 2001)
  4428 -----------------------------------
  4429 
  4430 *** Overview of INCOMPATIBILITIES ***
  4431 
  4432 * HOL: please note that theories in the Library and elsewhere often use the
  4433 new-style (Isar) format; to refer to their theorems in an ML script you must
  4434 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4435 
  4436 * HOL: inductive package no longer splits induction rule aggressively,
  4437 but only as far as specified by the introductions given; the old
  4438 format may be recovered via ML function complete_split_rule or attribute
  4439 'split_rule (complete)';
  4440 
  4441 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4442 gfp_Tarski to gfp_unfold;
  4443 
  4444 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4445 
  4446 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4447 relation); infix "^^" has been renamed "``"; infix "``" has been
  4448 renamed "`"; "univalent" has been renamed "single_valued";
  4449 
  4450 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4451 operation;
  4452 
  4453 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4454 
  4455 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4456 
  4457 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4458 consequence, it is no longer monotonic wrt. the local goal context
  4459 (which is now passed through the inductive cases);
  4460 
  4461 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4462 \<gg> to \<ggreater>;
  4463 
  4464 
  4465 *** Document preparation ***
  4466 
  4467 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4468 available: are "it" for near math-mode best-style output, "sl" for
  4469 slanted text style, and "tt" for plain type-writer; if no
  4470 \isabellestyle command is given, output is according to slanted
  4471 type-writer);
  4472 
  4473 * support sub/super scripts (for single symbols only), input syntax is
  4474 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4475 
  4476 * some more standard symbols; see Appendix A of the system manual for
  4477 the complete list of symbols defined in isabellesym.sty;
  4478 
  4479 * improved isabelle style files; more abstract symbol implementation
  4480 (should now use \isamath{...} and \isatext{...} in custom symbol
  4481 definitions);
  4482 
  4483 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4484 state; Note that presentation of goal states does not conform to
  4485 actual human-readable proof documents.  Please do not include goal
  4486 states into document output unless you really know what you are doing!
  4487 
  4488 * proper indentation of antiquoted output with proportional LaTeX
  4489 fonts;
  4490 
  4491 * no_document ML operator temporarily disables LaTeX document
  4492 generation;
  4493 
  4494 * isatool unsymbolize tunes sources for plain ASCII communication;
  4495 
  4496 
  4497 *** Isar ***
  4498 
  4499 * Pure: Isar now suffers initial goal statements to contain unbound
  4500 schematic variables (this does not conform to actual readable proof
  4501 documents, due to unpredictable outcome and non-compositional proof
  4502 checking); users who know what they are doing may use schematic goals
  4503 for Prolog-style synthesis of proven results;
  4504 
  4505 * Pure: assumption method (an implicit finishing) now handles actual
  4506 rules as well;
  4507 
  4508 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4509 initial goal, declare "that" only as Pure intro (only for single
  4510 steps); the "that" rule assumption may now be involved in implicit
  4511 finishing, thus ".." becomes a feasible for trivial obtains;
  4512 
  4513 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4514 instance proofs may be performed by "..";
  4515 
  4516 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4517 statements as well;
  4518 
  4519 * Pure: more robust selection of calculational rules;
  4520 
  4521 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4522 rule (as well as the assumption rule);
  4523 
  4524 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4525 lemmas, using the graph browser tool;
  4526 
  4527 * Pure: predict failure of "show" in interactive mode;
  4528 
  4529 * Pure: 'thms_containing' now takes actual terms as arguments;
  4530 
  4531 * HOL: improved method 'induct' --- now handles non-atomic goals
  4532 (potential INCOMPATIBILITY); tuned error handling;
  4533 
  4534 * HOL: cases and induct rules now provide explicit hints about the
  4535 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4536 any remaining facts are inserted into the goal verbatim;
  4537 
  4538 * HOL: local contexts (aka cases) may now contain term bindings as
  4539 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4540 the result to be shown in each case;
  4541 
  4542 * HOL: added 'recdef_tc' command;
  4543 
  4544 * isatool convert assists in eliminating legacy ML scripts;
  4545 
  4546 
  4547 *** HOL ***
  4548 
  4549 * HOL/Library: a collection of generic theories to be used together
  4550 with main HOL; the theory loader path already includes this directory
  4551 by default; the following existing theories have been moved here:
  4552 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4553 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4554 
  4555 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4556 modelling and verification task performed in Isabelle/HOL +
  4557 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4558 
  4559 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4560 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4561 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4562 'domain', this makes the theory consistent with mathematical
  4563 literature;
  4564 
  4565 * HOL basics: added overloaded operations "inverse" and "divide"
  4566 (infix "/"), syntax for generic "abs" operation, generic summation
  4567 operator \<Sum>;
  4568 
  4569 * HOL/typedef: simplified package, provide more useful rules (see also
  4570 HOL/subset.thy);
  4571 
  4572 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4573 now expressed as a proper nested rule (old-style tactic scripts may
  4574 require atomize_strip_tac to cope with non-atomic premises);
  4575 
  4576 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4577 to "split_conv" (old name still available for compatibility);
  4578 
  4579 * HOL: improved concrete syntax for strings (e.g. allows translation
  4580 rules with string literals);
  4581 
  4582 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4583  and Fleuriot's mechanization of analysis, including the transcendental
  4584  functions for the reals;
  4585 
  4586 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4587 
  4588 
  4589 *** CTT ***
  4590 
  4591 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4592 "lam" is displayed as TWO lambda-symbols
  4593 
  4594 * CTT: theory Main now available, containing everything (that is, Bool
  4595 and Arith);
  4596 
  4597 
  4598 *** General ***
  4599 
  4600 * Pure: the Simplifier has been implemented properly as a derived rule
  4601 outside of the actual kernel (at last!); the overall performance
  4602 penalty in practical applications is about 50%, while reliability of
  4603 the Isabelle inference kernel has been greatly improved;
  4604 
  4605 * print modes "brackets" and "no_brackets" control output of nested =>
  4606 (types) and ==> (props); the default behaviour is "brackets";
  4607 
  4608 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4609 as assumptions as well;
  4610 
  4611 * system: support Poly/ML 4.0;
  4612 
  4613 * system: isatool install handles KDE version 1 or 2;
  4614 
  4615 
  4616 
  4617 New in Isabelle99-1 (October 2000)
  4618 ----------------------------------
  4619 
  4620 *** Overview of INCOMPATIBILITIES ***
  4621 
  4622 * HOL: simplification of natural numbers is much changed; to partly
  4623 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4624 issue the following ML commands:
  4625 
  4626   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4627   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4628 
  4629 * HOL: simplification no longer dives into case-expressions; this is
  4630 controlled by "t.weak_case_cong" for each datatype t;
  4631 
  4632 * HOL: nat_less_induct renamed to less_induct;
  4633 
  4634 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4635 fixsome to patch .thy and .ML sources automatically;
  4636 
  4637   select_equality  -> some_equality
  4638   select_eq_Ex     -> some_eq_ex
  4639   selectI2EX       -> someI2_ex
  4640   selectI2         -> someI2
  4641   selectI          -> someI
  4642   select1_equality -> some1_equality
  4643   Eps_sym_eq       -> some_sym_eq_trivial
  4644   Eps_eq           -> some_eq_trivial
  4645 
  4646 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4647 
  4648 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4649 instead);
  4650 
  4651 * HOL: the recursion equations generated by 'recdef' are now called
  4652 f.simps instead of f.rules;
  4653 
  4654 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4655 
  4656 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4657 sometimes be needed;
  4658 
  4659 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4660 
  4661 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4662 
  4663 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4664 product is now "<*>" instead of "Times"; the lexicographic product is
  4665 now "<*lex*>" instead of "**";
  4666 
  4667 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4668 of main HOL, but was unused); better use HOL's datatype package;
  4669 
  4670 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4671 the old syntax may be recovered as follows:
  4672 
  4673   syntax (symbols)
  4674     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4675       (infixl "\\<oplus>" 100)
  4676 
  4677 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4678 
  4679 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4680 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4681 internally;
  4682 
  4683 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4684 changed from A/r to A//r;
  4685 
  4686 * ZF: new treatment of arithmetic (nat & int) may break some old
  4687 proofs;
  4688 
  4689 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4690 rulify -> rule_format, elimify -> elim_format, ...);
  4691 
  4692 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4693 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4694 should have to change intro!! to intro? only); replaced "delrule" by
  4695 "rule del";
  4696 
  4697 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4698 
  4699 * Provers: strengthened force_tac by using new first_best_tac;
  4700 
  4701 * LaTeX document preparation: several changes of isabelle.sty (see
  4702 lib/texinputs);
  4703 
  4704 
  4705 *** Document preparation ***
  4706 
  4707 * formal comments (text blocks etc.) in new-style theories may now
  4708 contain antiquotations of thm/prop/term/typ/text to be presented
  4709 according to latex print mode; concrete syntax is like this:
  4710 @{term[show_types] "f(x) = a + x"};
  4711 
  4712 * isatool mkdir provides easy setup of Isabelle session directories,
  4713 including proper document sources;
  4714 
  4715 * generated LaTeX sources are now deleted after successful run
  4716 (isatool document -c); may retain a copy somewhere else via -D option
  4717 of isatool usedir;
  4718 
  4719 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4720 style files, achieving self-contained LaTeX sources and simplifying
  4721 LaTeX debugging;
  4722 
  4723 * old-style theories now produce (crude) LaTeX output as well;
  4724 
  4725 * browser info session directories are now self-contained (may be put
  4726 on WWW server seperately); improved graphs of nested sessions; removed
  4727 graph for 'all sessions';
  4728 
  4729 * several improvements in isabelle style files; \isabellestyle{it}
  4730 produces fake math mode output; \isamarkupheader is now \section by
  4731 default; see lib/texinputs/isabelle.sty etc.;
  4732 
  4733 
  4734 *** Isar ***
  4735 
  4736 * Isar/Pure: local results and corresponding term bindings are now
  4737 subject to Hindley-Milner polymorphism (similar to ML); this
  4738 accommodates incremental type-inference very nicely;
  4739 
  4740 * Isar/Pure: new derived language element 'obtain' supports
  4741 generalized existence reasoning;
  4742 
  4743 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4744 support accumulation of results, without applying any rules yet;
  4745 useful to collect intermediate results without explicit name
  4746 references, and for use with transitivity rules with more than 2
  4747 premises;
  4748 
  4749 * Isar/Pure: scalable support for case-analysis type proofs: new
  4750 'case' language element refers to local contexts symbolically, as
  4751 produced by certain proof methods; internally, case names are attached
  4752 to theorems as "tags";
  4753 
  4754 * Isar/Pure: theory command 'hide' removes declarations from
  4755 class/type/const name spaces;
  4756 
  4757 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4758 indicate potential overloading;
  4759 
  4760 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4761 
  4762 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4763 "{a,b,c}" instead of {a,b,c};
  4764 
  4765 * Isar/Pure now provides its own version of intro/elim/dest
  4766 attributes; useful for building new logics, but beware of confusion
  4767 with the version in Provers/classical;
  4768 
  4769 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4770 case name 'antecedent';
  4771 
  4772 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4773 to the current context is now done automatically);
  4774 
  4775 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4776 for definining proof methods in ML;
  4777 
  4778 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4779 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4780 most cases, one should have to change intro!! to intro? only);
  4781 replaced "delrule" by "rule del";
  4782 
  4783 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4784 'symmetric' attribute (the latter supercedes [RS sym]);
  4785 
  4786 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4787 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4788 well (including splits);
  4789 
  4790 * Isar/Provers: Simplifier and Classical methods now support all kind
  4791 of modifiers used in the past, including 'cong', 'iff', etc.
  4792 
  4793 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4794 of Simplifier and Classical reasoner);
  4795 
  4796 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4797 now support named cases; major packages (inductive, datatype, primrec,
  4798 recdef) support case names and properly name parameters;
  4799 
  4800 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4801 monotonicity conditions are extracted to be proven at end of
  4802 calculations;
  4803 
  4804 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4805 method anyway;
  4806 
  4807 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4808 split_if split_if_asm; datatype package provides theorems foo.splits =
  4809 foo.split foo.split_asm for each datatype;
  4810 
  4811 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4812 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4813 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4814 use "(cases (simplified))" method in proper proof texts);
  4815 
  4816 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4817 
  4818 * Isar: names of theorems etc. may be natural numbers as well;
  4819 
  4820 * Isar: 'pr' command: optional arguments for goals_limit and
  4821 ProofContext.prems_limit; no longer prints theory contexts, but only
  4822 proof states;
  4823 
  4824 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4825 additional print modes to be specified; e.g. "pr(latex)" will print
  4826 proof state according to the Isabelle LaTeX style;
  4827 
  4828 * Isar: improved support for emulating tactic scripts, including proof
  4829 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4830 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4831 (for HOL datatypes);
  4832 
  4833 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4834 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4835 'proof method scripts' have to be in depth-first order;
  4836 
  4837 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4838 
  4839 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4840 should instead use individual commands for printing items
  4841 (print_commands, print_methods etc.);
  4842 
  4843 * Isar: added 'nothing' --- the empty list of theorems;
  4844 
  4845 
  4846 *** HOL ***
  4847 
  4848 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4849 corresponding virtual machine and a specification of its bytecode
  4850 verifier and a lightweight bytecode verifier, including proofs of
  4851 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4852 Cornelia Pusch (see also the homepage of project Bali at
  4853 http://isabelle.in.tum.de/Bali/);
  4854 
  4855 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4856 Clemens Ballarin;
  4857 
  4858 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4859 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4860 Rasmussen;
  4861 
  4862 * HOL/Lattice: fundamental concepts of lattice theory and order
  4863 structures, including duals, properties of bounds versus algebraic
  4864 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4865 Theorem for complete lattices etc.; may also serve as a demonstration
  4866 for abstract algebraic reasoning using axiomatic type classes, and
  4867 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4868 
  4869 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4870 von Oheimb;
  4871 
  4872 * HOL/IMPP: extension of IMP with local variables and mutually
  4873 recursive procedures, by David von Oheimb;
  4874 
  4875 * HOL/Lambda: converted into new-style theory and document;
  4876 
  4877 * HOL/ex/Multiquote: example of multiple nested quotations and
  4878 anti-quotations -- basically a generalized version of de-Bruijn
  4879 representation; very useful in avoiding lifting of operations;
  4880 
  4881 * HOL/record: added general record equality rule to simpset; fixed
  4882 select-update simplification procedure to handle extended records as
  4883 well; admit "r" as field name;
  4884 
  4885 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4886 other numeric types and also as the identity of groups, rings, etc.;
  4887 
  4888 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4889 Types nat and int belong to this axclass;
  4890 
  4891 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4892    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4893    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4894   two terms #m*u and #n*u are replaced by #(m+n)*u
  4895     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4896   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4897     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4898 
  4899 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4900 powerful prover for predicate logic but knows nothing of clasets; see
  4901 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4902 
  4903 * HOL: new version of "case_tac" subsumes both boolean case split and
  4904 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4905 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4906 
  4907 * HOL: simplification no longer dives into case-expressions: only the
  4908 selector expression is simplified, but not the remaining arms; to
  4909 enable full simplification of case-expressions for datatype t, you may
  4910 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4911 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4912 
  4913 * HOL/recdef: the recursion equations generated by 'recdef' for
  4914 function 'f' are now called f.simps instead of f.rules; if all
  4915 termination conditions are proved automatically, these simplification
  4916 rules are added to the simpset, as in primrec; rules may be named
  4917 individually as well, resulting in a separate list of theorems for
  4918 each equation;
  4919 
  4920 * HOL/While is a new theory that provides a while-combinator. It
  4921 permits the definition of tail-recursive functions without the
  4922 provision of a termination measure. The latter is necessary once the
  4923 invariant proof rule for while is applied.
  4924 
  4925 * HOL: new (overloaded) notation for the set of elements below/above
  4926 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4927 
  4928 * HOL: theorems impI, allI, ballI bound as "strip";
  4929 
  4930 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4931 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4932 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4933 
  4934 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4935 
  4936 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4937 main HOL, but was unused);
  4938 
  4939 * HOL: fewer consts declared as global (e.g. have to refer to
  4940 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4941 
  4942 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4943 in case of overlap with user translations (e.g. judgements over
  4944 tuples); (note that the underlying logical represenation is still
  4945 bogus);
  4946 
  4947 
  4948 *** ZF ***
  4949 
  4950 * ZF: simplification automatically cancels common terms in arithmetic
  4951 expressions over nat and int;
  4952 
  4953 * ZF: new treatment of nat to minimize type-checking: all operators
  4954 coerce their operands to a natural number using the function natify,
  4955 making the algebraic laws unconditional;
  4956 
  4957 * ZF: as above, for int: operators coerce their operands to an integer
  4958 using the function intify;
  4959 
  4960 * ZF: the integer library now contains many of the usual laws for the
  4961 orderings, including $<=, and monotonicity laws for $+ and $*;
  4962 
  4963 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4964 simplification;
  4965 
  4966 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4967 to the simplifier and classical reasoner simultaneously;
  4968 
  4969 
  4970 *** General ***
  4971 
  4972 * Provers: blast_tac now handles actual object-logic rules as
  4973 assumptions; note that auto_tac uses blast_tac internally as well;
  4974 
  4975 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4976 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4977 
  4978 * Provers: delrules now handles destruct rules as well (no longer need
  4979 explicit make_elim);
  4980 
  4981 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4982   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4983 use instead the strong form,
  4984   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4985 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4986 from destruct-rules;
  4987 
  4988 * Provers: Simplifier.easy_setup provides a fast path to basic
  4989 Simplifier setup for new object-logics;
  4990 
  4991 * Pure: AST translation rules no longer require constant head on LHS;
  4992 
  4993 * Pure: improved name spaces: ambiguous output is qualified; support
  4994 for hiding of names;
  4995 
  4996 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4997 XSYMBOL_HOME; no longer need to do manual configuration in most
  4998 situations;
  4999 
  5000 * system: compression of ML heaps images may now be controlled via -c
  5001 option of isabelle and isatool usedir (currently only observed by
  5002 Poly/ML);
  5003 
  5004 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5005 useful for remote X11);
  5006 
  5007 * system: provide TAGS file for Isabelle sources;
  5008 
  5009 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5010 order;
  5011 
  5012 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5013 timing flag supersedes proof_timing and Toplevel.trace;
  5014 
  5015 * ML: new combinators |>> and |>>> for incremental transformations
  5016 with secondary results (e.g. certain theory extensions):
  5017 
  5018 * ML: PureThy.add_defs gets additional argument to indicate potential
  5019 overloading (usually false);
  5020 
  5021 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5022 results;
  5023 
  5024 
  5025 
  5026 New in Isabelle99 (October 1999)
  5027 --------------------------------
  5028 
  5029 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5030 
  5031 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5032 are no longer simplified.  (This allows the simplifier to unfold recursive
  5033 functional programs.)  To restore the old behaviour, declare
  5034 
  5035     Delcongs [if_weak_cong];
  5036 
  5037 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5038 complement;
  5039 
  5040 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5041 
  5042 * HOL/datatype: mutual_induct_tac no longer exists --
  5043   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5044 
  5045 * HOL/typedef: fixed type inference for representing set; type
  5046 arguments now have to occur explicitly on the rhs as type constraints;
  5047 
  5048 * ZF: The con_defs part of an inductive definition may no longer refer
  5049 to constants declared in the same theory;
  5050 
  5051 * HOL, ZF: the function mk_cases, generated by the inductive
  5052 definition package, has lost an argument.  To simplify its result, it
  5053 uses the default simpset instead of a supplied list of theorems.
  5054 
  5055 * HOL/List: the constructors of type list are now Nil and Cons;
  5056 
  5057 * Simplifier: the type of the infix ML functions
  5058         setSSolver addSSolver setSolver addSolver
  5059 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5060 for packaging solvers. A solver is created via
  5061         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5062 where the string argument is only a comment.
  5063 
  5064 
  5065 *** Proof tools ***
  5066 
  5067 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5068 decision procedure for linear arithmetic. Currently it is used for
  5069 types `nat', `int', and `real' in HOL (see below); it can, should and
  5070 will be instantiated for other types and logics as well.
  5071 
  5072 * The simplifier now accepts rewrite rules with flexible heads, eg
  5073      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5074   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5075   matching.
  5076 
  5077 
  5078 *** General ***
  5079 
  5080 * New Isabelle/Isar subsystem provides an alternative to traditional
  5081 tactical theorem proving; together with the ProofGeneral/isar user
  5082 interface it offers an interactive environment for developing human
  5083 readable proof documents (Isar == Intelligible semi-automated
  5084 reasoning); for further information see isatool doc isar-ref,
  5085 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5086 
  5087 * improved and simplified presentation of theories: better HTML markup
  5088 (including colors), graph views in several sizes; isatool usedir now
  5089 provides a proper interface for user theories (via -P option); actual
  5090 document preparation based on (PDF)LaTeX is available as well (for
  5091 new-style theories only); see isatool doc system for more information;
  5092 
  5093 * native support for Proof General, both for classic Isabelle and
  5094 Isabelle/Isar;
  5095 
  5096 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5097 using the graph browser tool;
  5098 
  5099 * Isabelle manuals now also available as PDF;
  5100 
  5101 * theory loader rewritten from scratch (may not be fully
  5102 bug-compatible); old loadpath variable has been replaced by show_path,
  5103 add_path, del_path, reset_path functions; new operations such as
  5104 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5105 isatool doc ref);
  5106 
  5107 * improved isatool install: option -k creates KDE application icon,
  5108 option -p DIR installs standalone binaries;
  5109 
  5110 * added ML_PLATFORM setting (useful for cross-platform installations);
  5111 more robust handling of platform specific ML images for SML/NJ;
  5112 
  5113 * the settings environment is now statically scoped, i.e. it is never
  5114 created again in sub-processes invoked from isabelle, isatool, or
  5115 Isabelle;
  5116 
  5117 * path element specification '~~' refers to '$ISABELLE_HOME';
  5118 
  5119 * in locales, the "assumes" and "defines" parts may be omitted if
  5120 empty;
  5121 
  5122 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5123 long arrows);
  5124 
  5125 * new print_mode "HTML";
  5126 
  5127 * new flag show_tags controls display of tags of theorems (which are
  5128 basically just comments that may be attached by some tools);
  5129 
  5130 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5131 mode and goal output format:
  5132 
  5133 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5134 244c244
  5135 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5136 ---
  5137 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5138 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5139 181c181
  5140 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5141 ---
  5142 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5143 
  5144 * function bind_thms stores lists of theorems (cf. bind_thm);
  5145 
  5146 * new shorthand tactics ftac, eatac, datac, fatac;
  5147 
  5148 * qed (and friends) now accept "" as result name; in that case the
  5149 theorem is not stored, but proper checks and presentation of the
  5150 result still apply;
  5151 
  5152 * theorem database now also indexes constants "Trueprop", "all",
  5153 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5154 
  5155 
  5156 *** HOL ***
  5157 
  5158 ** HOL arithmetic **
  5159 
  5160 * There are now decision procedures for linear arithmetic over nat and
  5161 int:
  5162 
  5163 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5164 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5165 are treated as atomic; subformulae not involving type `nat' or `int'
  5166 are ignored; quantified subformulae are ignored unless they are
  5167 positive universal or negative existential. The tactic has to be
  5168 invoked by hand and can be a little bit slow. In particular, the
  5169 running time is exponential in the number of occurrences of `min' and
  5170 `max', and `-' on `nat'.
  5171 
  5172 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5173 (negated) (in)equalities among the premises and the conclusion into
  5174 account (i.e. no compound formulae) and does not know about `min' and
  5175 `max', and `-' on `nat'. It is fast and is used automatically by the
  5176 simplifier.
  5177 
  5178 NB: At the moment, these decision procedures do not cope with mixed
  5179 nat/int formulae where the two parts interact, such as `m < n ==>
  5180 int(m) < int(n)'.
  5181 
  5182 * HOL/Numeral provides a generic theory of numerals (encoded
  5183 efficiently as bit strings); setup for types nat/int/real is in place;
  5184 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5185 int, existing theories and proof scripts may require a few additional
  5186 type constraints;
  5187 
  5188 * integer division and remainder can now be performed on constant
  5189 arguments;
  5190 
  5191 * many properties of integer multiplication, division and remainder
  5192 are now available;
  5193 
  5194 * An interface to the Stanford Validity Checker (SVC) is available through the
  5195 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5196 are proved automatically.  SVC must be installed separately, and its results
  5197 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5198 invocation of the underlying oracle).  For SVC see
  5199   http://verify.stanford.edu/SVC
  5200 
  5201 * IsaMakefile: the HOL-Real target now builds an actual image;
  5202 
  5203 
  5204 ** HOL misc **
  5205 
  5206 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5207 (in Isabelle/Isar) -- by Gertrud Bauer;
  5208 
  5209 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5210 analysis for assembly languages with subtypes;
  5211 
  5212 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5213 -- avoids syntactic ambiguities and treats state, transition, and
  5214 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5215 changed syntax and (many) tactics;
  5216 
  5217 * HOL/inductive: Now also handles more general introduction rules such
  5218   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5219   theorems are now maintained within the theory (maintained via the
  5220   "mono" attribute);
  5221 
  5222 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5223   (using function types) such as
  5224 
  5225   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5226 
  5227 * HOL/record: record_simproc (part of the default simpset) takes care
  5228 of selectors applied to updated records; record_split_tac is no longer
  5229 part of the default claset; update_defs may now be removed from the
  5230 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5231 
  5232   claset_ref () := claset() addSWrapper record_split_wrapper;
  5233   Delsimprocs [record_simproc]
  5234 
  5235 * HOL/typedef: fixed type inference for representing set; type
  5236 arguments now have to occur explicitly on the rhs as type constraints;
  5237 
  5238 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5239 names rather than an ML expression;
  5240 
  5241 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5242 supplied later.  Program schemes can be defined, such as
  5243     "While B C s = (if B s then While B C (C s) else s)"
  5244 where the well-founded relation can be chosen after B and C have been given.
  5245 
  5246 * HOL/List: the constructors of type list are now Nil and Cons;
  5247 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5248 course, ML tools referring to List.list.op # etc. have to be adapted;
  5249 
  5250 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5251 disabled by default; run isabelle with option -m HOL to get back to
  5252 the original Gordon/HOL-style output;
  5253 
  5254 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5255 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5256 
  5257 * HOL basic syntax simplified (more orthogonal): all variants of
  5258 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5259 Eps operator is provided as well: "SOME x. P[x]";
  5260 
  5261 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5262 
  5263 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5264 thus available for user theories;
  5265 
  5266 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5267 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5268 time;
  5269 
  5270 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5271 several times and then mp;
  5272 
  5273 
  5274 *** LK ***
  5275 
  5276 * the notation <<...>> is now available as a notation for sequences of
  5277 formulas;
  5278 
  5279 * the simplifier is now installed
  5280 
  5281 * the axiom system has been generalized (thanks to Soren Heilmann)
  5282 
  5283 * the classical reasoner now has a default rule database
  5284 
  5285 
  5286 *** ZF ***
  5287 
  5288 * new primrec section allows primitive recursive functions to be given
  5289 directly (as in HOL) over datatypes and the natural numbers;
  5290 
  5291 * new tactics induct_tac and exhaust_tac for induction (or case
  5292 analysis) over datatypes and the natural numbers;
  5293 
  5294 * the datatype declaration of type T now defines the recursor T_rec;
  5295 
  5296 * simplification automatically does freeness reasoning for datatype
  5297 constructors;
  5298 
  5299 * automatic type-inference, with AddTCs command to insert new
  5300 type-checking rules;
  5301 
  5302 * datatype introduction rules are now added as Safe Introduction rules
  5303 to the claset;
  5304 
  5305 * the syntax "if P then x else y" is now available in addition to
  5306 if(P,x,y);
  5307 
  5308 
  5309 *** Internal programming interfaces ***
  5310 
  5311 * tuned simplifier trace output; new flag debug_simp;
  5312 
  5313 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5314 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5315 
  5316 * AxClass.axclass_tac lost the theory argument;
  5317 
  5318 * tuned current_goals_markers semantics: begin / end goal avoids
  5319 printing empty lines;
  5320 
  5321 * removed prs and prs_fn hook, which was broken because it did not
  5322 include \n in its semantics, forcing writeln to add one
  5323 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5324 string -> unit if you really want to output text without newline;
  5325 
  5326 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5327 plain output, interface builders may have to enable 'isabelle_font'
  5328 mode to get Isabelle font glyphs as before;
  5329 
  5330 * refined token_translation interface; INCOMPATIBILITY: output length
  5331 now of type real instead of int;
  5332 
  5333 * theory loader actions may be traced via new ThyInfo.add_hook
  5334 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5335 your own database of information attached to *whole* theories -- as
  5336 opposed to intra-theory data slots offered via TheoryDataFun;
  5337 
  5338 * proper handling of dangling sort hypotheses (at last!);
  5339 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5340 extra sort hypotheses that can be witnessed from the type signature;
  5341 the force_strip_shyps flag is gone, any remaining shyps are simply
  5342 left in the theorem (with a warning issued by strip_shyps_warning);
  5343 
  5344 
  5345 
  5346 New in Isabelle98-1 (October 1998)
  5347 ----------------------------------
  5348 
  5349 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5350 
  5351 * several changes of automated proof tools;
  5352 
  5353 * HOL: major changes to the inductive and datatype packages, including
  5354 some minor incompatibilities of theory syntax;
  5355 
  5356 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5357 called `inj_on';
  5358 
  5359 * HOL: removed duplicate thms in Arith:
  5360   less_imp_add_less  should be replaced by  trans_less_add1
  5361   le_imp_add_le      should be replaced by  trans_le_add1
  5362 
  5363 * HOL: unary minus is now overloaded (new type constraints may be
  5364 required);
  5365 
  5366 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5367 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5368 now taken as an integer constant.
  5369 
  5370 * Pure: ML function 'theory_of' renamed to 'theory';
  5371 
  5372 
  5373 *** Proof tools ***
  5374 
  5375 * Simplifier:
  5376   1. Asm_full_simp_tac is now more aggressive.
  5377      1. It will sometimes reorient premises if that increases their power to
  5378         simplify.
  5379      2. It does no longer proceed strictly from left to right but may also
  5380         rotate premises to achieve further simplification.
  5381      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5382      old Asm_full_simp_tac in that it does not rotate premises.
  5383   2. The simplifier now knows a little bit about nat-arithmetic.
  5384 
  5385 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5386 allows for selected deletion of wrappers, by introduction of names for
  5387 wrapper functionals.  This implies that addbefore, addSbefore,
  5388 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5389 and that adding two tactics with the same name overwrites the first
  5390 one (emitting a warning).
  5391   type wrapper = (int -> tactic) -> (int -> tactic)
  5392   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5393   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5394   delWrapper, delSWrapper: claset *  string            -> claset
  5395   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5396 
  5397 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5398 semantics; addbefore now affects only the unsafe part of step_tac
  5399 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5400 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5401 by Force_tac;
  5402 
  5403 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5404 compWrapper; added safe wrapper (and access functions for it);
  5405 
  5406 * HOL/split_all_tac is now much faster and fails if there is nothing
  5407 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5408 and the names of the automatically generated variables have changed.
  5409 split_all_tac has moved within claset() from unsafe wrappers to safe
  5410 wrappers, which means that !!-bound variables are split much more
  5411 aggressively, and safe_tac and clarify_tac now split such variables.
  5412 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5413 Note: the same holds for record_split_tac, which does the job of
  5414 split_all_tac for record fields.
  5415 
  5416 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5417 permanently to the default simpset using Addsplits just like
  5418 Addsimps. They can be removed via Delsplits just like
  5419 Delsimps. Lower-case versions are also available.
  5420 
  5421 * HOL/Simplifier: The rule split_if is now part of the default
  5422 simpset. This means that the simplifier will eliminate all occurrences
  5423 of if-then-else in the conclusion of a goal. To prevent this, you can
  5424 either remove split_if completely from the default simpset by
  5425 `Delsplits [split_if]' or remove it in a specific call of the
  5426 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5427 other case splitting rules to/from the default simpset: every datatype
  5428 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5429 t is the name of the datatype).
  5430 
  5431 * Classical reasoner / Simplifier combination: new force_tac (and
  5432 derivatives Force_tac, force) combines rewriting and classical
  5433 reasoning (and whatever other tools) similarly to auto_tac, but is
  5434 aimed to solve the given subgoal completely.
  5435 
  5436 
  5437 *** General ***
  5438 
  5439 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5440 and `goalw': the theory is no longer needed as an explicit argument -
  5441 the current theory context is used; assumptions are no longer returned
  5442 at the ML-level unless one of them starts with ==> or !!; it is
  5443 recommended to convert to these new commands using isatool fixgoal
  5444 (backup your sources first!);
  5445 
  5446 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5447 the current theory context, and 'theory' to lookup stored theories;
  5448 
  5449 * new theory section 'locale' for declaring constants, assumptions and
  5450 definitions that have local scope;
  5451 
  5452 * new theory section 'nonterminals' for purely syntactic types;
  5453 
  5454 * new theory section 'setup' for generic ML setup functions
  5455 (e.g. package initialization);
  5456 
  5457 * the distribution now includes Isabelle icons: see
  5458 lib/logo/isabelle-{small,tiny}.xpm;
  5459 
  5460 * isatool install - install binaries with absolute references to
  5461 ISABELLE_HOME/bin;
  5462 
  5463 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5464 
  5465 * print mode 'emacs' reserved for Isamode;
  5466 
  5467 * support multiple print (ast) translations per constant name;
  5468 
  5469 * theorems involving oracles are now printed with a suffixed [!];
  5470 
  5471 
  5472 *** HOL ***
  5473 
  5474 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5475 
  5476 * HOL/inductive package reorganized and improved: now supports mutual
  5477 definitions such as
  5478 
  5479   inductive EVEN ODD
  5480     intrs
  5481       null "0 : EVEN"
  5482       oddI "n : EVEN ==> Suc n : ODD"
  5483       evenI "n : ODD ==> Suc n : EVEN"
  5484 
  5485 new theorem list "elims" contains an elimination rule for each of the
  5486 recursive sets; inductive definitions now handle disjunctive premises
  5487 correctly (also ZF);
  5488 
  5489 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5490 "mutual_induct" no longer exists - the induction rule is always
  5491 contained in "induct";
  5492 
  5493 
  5494 * HOL/datatype package re-implemented and greatly improved: now
  5495 supports mutually recursive datatypes such as
  5496 
  5497   datatype
  5498     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5499             | SUM ('a aexp) ('a aexp)
  5500             | DIFF ('a aexp) ('a aexp)
  5501             | NUM 'a
  5502   and
  5503     'a bexp = LESS ('a aexp) ('a aexp)
  5504             | AND ('a bexp) ('a bexp)
  5505             | OR ('a bexp) ('a bexp)
  5506 
  5507 as well as indirectly recursive datatypes such as
  5508 
  5509   datatype
  5510     ('a, 'b) term = Var 'a
  5511                   | App 'b ((('a, 'b) term) list)
  5512 
  5513 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5514 induction on mutually / indirectly recursive datatypes.
  5515 
  5516 Primrec equations are now stored in theory and can be accessed via
  5517 <function_name>.simps.
  5518 
  5519 INCOMPATIBILITIES:
  5520 
  5521   - Theories using datatypes must now have theory Datatype as an
  5522     ancestor.
  5523   - The specific <typename>.induct_tac no longer exists - use the
  5524     generic induct_tac instead.
  5525   - natE has been renamed to nat.exhaust - use exhaust_tac
  5526     instead of res_inst_tac ... natE. Note that the variable
  5527     names in nat.exhaust differ from the names in natE, this
  5528     may cause some "fragile" proofs to fail.
  5529   - The theorems split_<typename>_case and split_<typename>_case_asm
  5530     have been renamed to <typename>.split and <typename>.split_asm.
  5531   - Since default sorts of type variables are now handled correctly,
  5532     some datatype definitions may have to be annotated with explicit
  5533     sort constraints.
  5534   - Primrec definitions no longer require function name and type
  5535     of recursive argument.
  5536 
  5537 Consider using isatool fixdatatype to adapt your theories and proof
  5538 scripts to the new package (backup your sources first!).
  5539 
  5540 
  5541 * HOL/record package: considerably improved implementation; now
  5542 includes concrete syntax for record types, terms, updates; theorems
  5543 for surjective pairing and splitting !!-bound record variables; proof
  5544 support is as follows:
  5545 
  5546   1) standard conversions (selectors or updates applied to record
  5547 constructor terms) are part of the standard simpset;
  5548 
  5549   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5550 made part of standard simpset and claset via addIffs;
  5551 
  5552   3) a tactic for record field splitting (record_split_tac) is part of
  5553 the standard claset (addSWrapper);
  5554 
  5555 To get a better idea about these rules you may retrieve them via
  5556 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5557 the name of your record type.
  5558 
  5559 The split tactic 3) conceptually simplifies by the following rule:
  5560 
  5561   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5562 
  5563 Thus any record variable that is bound by meta-all will automatically
  5564 blow up into some record constructor term, consequently the
  5565 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5566 solve record problems automatically.
  5567 
  5568 
  5569 * reorganized the main HOL image: HOL/Integ and String loaded by
  5570 default; theory Main includes everything;
  5571 
  5572 * automatic simplification of integer sums and comparisons, using cancellation;
  5573 
  5574 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5575 
  5576 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5577 
  5578 * many new identities for unions, intersections, set difference, etc.;
  5579 
  5580 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5581 called split_if, split_split, split_sum_case and split_nat_case (to go
  5582 with add/delsplits);
  5583 
  5584 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5585 (?x::unit) = (); this is made part of the default simpset, which COULD
  5586 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5587 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5588 unit_abs_eta_conv is added in order to counter the effect of
  5589 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5590 %u.f();
  5591 
  5592 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5593 makes more sense);
  5594 
  5595 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5596   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5597   disjointness reasoning but breaking a few old proofs.
  5598 
  5599 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5600 to 'converse' from 'inverse' (for compatibility with ZF and some
  5601 literature);
  5602 
  5603 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5604 the well-founded relation;
  5605 
  5606 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5607     Compl A.  The "Compl" syntax remains available as input syntax for this
  5608     release ONLY.
  5609 
  5610 * HOL/Update: new theory of function updates:
  5611     f(a:=b) == %x. if x=a then b else f x
  5612 may also be iterated as in f(a:=b,c:=d,...);
  5613 
  5614 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5615 
  5616 * HOL/List:
  5617   - new function list_update written xs[i:=v] that updates the i-th
  5618     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5619   - new function `upt' written [i..j(] which generates the list
  5620     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5621     bound write [i..j], which is a shorthand for [i..j+1(].
  5622   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5623 
  5624 * HOL/Arith:
  5625   - removed 'pred' (predecessor) function;
  5626   - generalized some theorems about n-1;
  5627   - many new laws about "div" and "mod";
  5628   - new laws about greatest common divisors (see theory ex/Primes);
  5629 
  5630 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5631 instead of "inverse";
  5632 
  5633 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5634   of the multiset ordering;
  5635 
  5636 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5637   (not included by default);
  5638 
  5639 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5640 
  5641 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5642   programs, i.e. different program variables may have different types.
  5643 
  5644 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5645   [previously, this check worked only if the rewrite rule was unconditional]
  5646   Now rew can involve either definitions or equalities (either == or =).
  5647 
  5648 
  5649 *** ZF ***
  5650 
  5651 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5652   only the theorems proved on ZF.ML;
  5653 
  5654 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5655   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5656   disjointness reasoning but breaking a few old proofs.
  5657 
  5658 * ZF/Update: new theory of function updates
  5659     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5660   may also be iterated as in f(a:=b,c:=d,...);
  5661 
  5662 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5663 
  5664 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5665   [previously, this check worked only if the rewrite rule was unconditional]
  5666   Now rew can involve either definitions or equalities (either == or =).
  5667 
  5668 * case_tac provided for compatibility with HOL
  5669     (like the old excluded_middle_tac, but with subgoals swapped)
  5670 
  5671 
  5672 *** Internal programming interfaces ***
  5673 
  5674 * Pure: several new basic modules made available for general use, see
  5675 also src/Pure/README;
  5676 
  5677 * improved the theory data mechanism to support encapsulation (data
  5678 kind name replaced by private Object.kind, acting as authorization
  5679 key); new type-safe user interface via functor TheoryDataFun; generic
  5680 print_data function becomes basically useless;
  5681 
  5682 * removed global_names compatibility flag -- all theory declarations
  5683 are qualified by default;
  5684 
  5685 * module Pure/Syntax now offers quote / antiquote translation
  5686 functions (useful for Hoare logic etc. with implicit dependencies);
  5687 see HOL/ex/Antiquote for an example use;
  5688 
  5689 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5690 cterm -> thm;
  5691 
  5692 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5693 subgoal;
  5694 
  5695 * Display.print_goals function moved to Locale.print_goals;
  5696 
  5697 * standard print function for goals supports current_goals_markers
  5698 variable for marking begin of proof, end of proof, start of goal; the
  5699 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5700 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5701 for example;
  5702 
  5703 
  5704 
  5705 New in Isabelle98 (January 1998)
  5706 --------------------------------
  5707 
  5708 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5709 
  5710 * changed lexical syntax of terms / types: dots made part of long
  5711 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5712 
  5713 * simpset (and claset) reference variable replaced by functions
  5714 simpset / simpset_ref;
  5715 
  5716 * no longer supports theory aliases (via merge) and non-trivial
  5717 implicit merge of thms' signatures;
  5718 
  5719 * most internal names of constants changed due to qualified names;
  5720 
  5721 * changed Pure/Sequence interface (see Pure/seq.ML);
  5722 
  5723 
  5724 *** General Changes ***
  5725 
  5726 * hierachically structured name spaces (for consts, types, axms, thms
  5727 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5728 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5729 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5730 long_names for fully qualified output names; NOTE: ML programs
  5731 (special tactics, packages etc.) referring to internal names may have
  5732 to be adapted to cope with fully qualified names; in case of severe
  5733 backward campatibility problems try setting 'global_names' at compile
  5734 time to have enrything declared within a flat name space; one may also
  5735 fine tune name declarations in theories via the 'global' and 'local'
  5736 section;
  5737 
  5738 * reimplemented the implicit simpset and claset using the new anytype
  5739 data filed in signatures; references simpset:simpset ref etc. are
  5740 replaced by functions simpset:unit->simpset and
  5741 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5742 to patch your ML files accordingly;
  5743 
  5744 * HTML output now includes theory graph data for display with Java
  5745 applet or isatool browser; data generated automatically via isatool
  5746 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5747 
  5748 * defs may now be conditional; improved rewrite_goals_tac to handle
  5749 conditional equations;
  5750 
  5751 * defs now admits additional type arguments, using TYPE('a) syntax;
  5752 
  5753 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5754 creates a new theory node; implicit merge of thms' signatures is
  5755 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5756 transfer:theory->thm->thm in (rare) cases;
  5757 
  5758 * improved handling of draft signatures / theories; draft thms (and
  5759 ctyps, cterms) are automatically promoted to real ones;
  5760 
  5761 * slightly changed interfaces for oracles: admit many per theory, named
  5762 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5763 
  5764 * print_goals: optional output of const types (set show_consts and
  5765 show_types);
  5766 
  5767 * improved output of warnings (###) and errors (***);
  5768 
  5769 * subgoal_tac displays a warning if the new subgoal has type variables;
  5770 
  5771 * removed old README and Makefiles;
  5772 
  5773 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5774 
  5775 * removed obsolete init_pps and init_database;
  5776 
  5777 * deleted the obsolete tactical STATE, which was declared by
  5778     fun STATE tacfun st = tacfun st st;
  5779 
  5780 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5781 (which abbreviates $HOME);
  5782 
  5783 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5784 use isatool fixseq to adapt your ML programs (this works for fully
  5785 qualified references to the Sequence structure only!);
  5786 
  5787 * use_thy no longer requires writable current directory; it always
  5788 reloads .ML *and* .thy file, if either one is out of date;
  5789 
  5790 
  5791 *** Classical Reasoner ***
  5792 
  5793 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5794 tactics that use classical reasoning to simplify a subgoal without
  5795 splitting it into several subgoals;
  5796 
  5797 * Safe_tac: like safe_tac but uses the default claset;
  5798 
  5799 
  5800 *** Simplifier ***
  5801 
  5802 * added simplification meta rules:
  5803     (asm_)(full_)simplify: simpset -> thm -> thm;
  5804 
  5805 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5806 logics (again);
  5807 
  5808 * added prems argument to simplification procedures;
  5809 
  5810 * HOL, FOL, ZF: added infix function `addsplits':
  5811   instead of `<simpset> setloop (split_tac <thms>)'
  5812   you can simply write `<simpset> addsplits <thms>'
  5813 
  5814 
  5815 *** Syntax ***
  5816 
  5817 * TYPE('a) syntax for type reflection terms;
  5818 
  5819 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5820 
  5821 * pretty printer: changed order of mixfix annotation preference (again!);
  5822 
  5823 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5824 
  5825 
  5826 *** HOL ***
  5827 
  5828 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5829   with `addloop' of the simplifier to faciliate case splitting in premises.
  5830 
  5831 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5832 
  5833 * HOL/Auth: new protocol proofs including some for the Internet
  5834   protocol TLS;
  5835 
  5836 * HOL/Map: new theory of `maps' a la VDM;
  5837 
  5838 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5839 cancelling out common nat summands from =, <, <= (in)equalities, or
  5840 differences; simplification procedures nat_cancel_factor for
  5841 cancelling common factor from =, <, <= (in)equalities over natural
  5842 sums; nat_cancel contains both kinds of procedures, it is installed by
  5843 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5844 
  5845 * HOL/simplifier: terms of the form
  5846   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5847   are rewritten to
  5848   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5849   and those of the form
  5850   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5851   are rewritten to
  5852   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5853 
  5854 * HOL/datatype
  5855   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5856 
  5857   P(t_case f1 ... fn x) =
  5858      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5859         ...
  5860        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5861      )
  5862 
  5863   and a theorem `split_t_case_asm' of the form
  5864 
  5865   P(t_case f1 ... fn x) =
  5866     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5867         ...
  5868        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5869      )
  5870   which can be added to a simpset via `addsplits'. The existing theorems
  5871   expand_list_case and expand_option_case have been renamed to
  5872   split_list_case and split_option_case.
  5873 
  5874 * HOL/Arithmetic:
  5875   - `pred n' is automatically converted to `n-1'.
  5876     Users are strongly encouraged not to use `pred' any longer,
  5877     because it will disappear altogether at some point.
  5878   - Users are strongly encouraged to write "0 < n" rather than
  5879     "n ~= 0". Theorems and proof tools have been modified towards this
  5880     `standard'.
  5881 
  5882 * HOL/Lists:
  5883   the function "set_of_list" has been renamed "set" (and its theorems too);
  5884   the function "nth" now takes its arguments in the reverse order and
  5885   has acquired the infix notation "!" as in "xs!n".
  5886 
  5887 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5888 
  5889 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5890   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5891 
  5892 * HOL/record: extensible records with schematic structural subtyping
  5893 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5894 still lacks various theorems and concrete record syntax;
  5895 
  5896 
  5897 *** HOLCF ***
  5898 
  5899 * removed "axioms" and "generated by" sections;
  5900 
  5901 * replaced "ops" section by extended "consts" section, which is capable of
  5902   handling the continuous function space "->" directly;
  5903 
  5904 * domain package:
  5905   . proves theorems immediately and stores them in the theory,
  5906   . creates hierachical name space,
  5907   . now uses normal mixfix annotations (instead of cinfix...),
  5908   . minor changes to some names and values (for consistency),
  5909   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5910   . separator between mutual domain defs: changed "," to "and",
  5911   . improved handling of sort constraints;  now they have to
  5912     appear on the left-hand side of the equations only;
  5913 
  5914 * fixed LAM <x,y,zs>.b syntax;
  5915 
  5916 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5917 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5918 
  5919 
  5920 *** FOL and ZF ***
  5921 
  5922 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5923   with `addloop' of the simplifier to faciliate case splitting in premises.
  5924 
  5925 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5926 in HOL, they strip ALL and --> from proved theorems;
  5927 
  5928 
  5929 
  5930 New in Isabelle94-8 (May 1997)
  5931 ------------------------------
  5932 
  5933 *** General Changes ***
  5934 
  5935 * new utilities to build / run / maintain Isabelle etc. (in parts
  5936 still somewhat experimental); old Makefiles etc. still functional;
  5937 
  5938 * new 'Isabelle System Manual';
  5939 
  5940 * INSTALL text, together with ./configure and ./build scripts;
  5941 
  5942 * reimplemented type inference for greater efficiency, better error
  5943 messages and clean internal interface;
  5944 
  5945 * prlim command for dealing with lots of subgoals (an easier way of
  5946 setting goals_limit);
  5947 
  5948 
  5949 *** Syntax ***
  5950 
  5951 * supports alternative (named) syntax tables (parser and pretty
  5952 printer); internal interface is provided by add_modesyntax(_i);
  5953 
  5954 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5955 be used in conjunction with the Isabelle symbol font; uses the
  5956 "symbols" syntax table;
  5957 
  5958 * added token_translation interface (may translate name tokens in
  5959 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5960 the current print_mode); IMPORTANT: user print translation functions
  5961 are responsible for marking newly introduced bounds
  5962 (Syntax.mark_boundT);
  5963 
  5964 * token translations for modes "xterm" and "xterm_color" that display
  5965 names in bold, underline etc. or colors (which requires a color
  5966 version of xterm);
  5967 
  5968 * infixes may now be declared with names independent of their syntax;
  5969 
  5970 * added typed_print_translation (like print_translation, but may
  5971 access type of constant);
  5972 
  5973 
  5974 *** Classical Reasoner ***
  5975 
  5976 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5977 some limitations.  Blast_tac...
  5978   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5979   + ignores elimination rules that don't have the correct format
  5980         (the conclusion MUST be a formula variable)
  5981   + ignores types, which can make HOL proofs fail
  5982   + rules must not require higher-order unification, e.g. apply_type in ZF
  5983     [message "Function Var's argument not a bound variable" relates to this]
  5984   + its proof strategy is more general but can actually be slower
  5985 
  5986 * substitution with equality assumptions no longer permutes other
  5987 assumptions;
  5988 
  5989 * minor changes in semantics of addafter (now called addaltern); renamed
  5990 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5991 (and access functions for it);
  5992 
  5993 * improved combination of classical reasoner and simplifier:
  5994   + functions for handling clasimpsets
  5995   + improvement of addss: now the simplifier is called _after_ the
  5996     safe steps.
  5997   + safe variant of addss called addSss: uses safe simplifications
  5998     _during_ the safe steps. It is more complete as it allows multiple
  5999     instantiations of unknowns (e.g. with slow_tac).
  6000 
  6001 *** Simplifier ***
  6002 
  6003 * added interface for simplification procedures (functions that
  6004 produce *proven* rewrite rules on the fly, depending on current
  6005 redex);
  6006 
  6007 * ordering on terms as parameter (used for ordered rewriting);
  6008 
  6009 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6010 
  6011 * the solver is now split into a safe and an unsafe part.
  6012 This should be invisible for the normal user, except that the
  6013 functions setsolver and addsolver have been renamed to setSolver and
  6014 addSolver; added safe_asm_full_simp_tac;
  6015 
  6016 
  6017 *** HOL ***
  6018 
  6019 * a generic induction tactic `induct_tac' which works for all datatypes and
  6020 also for type `nat';
  6021 
  6022 * a generic case distinction tactic `exhaust_tac' which works for all
  6023 datatypes and also for type `nat';
  6024 
  6025 * each datatype comes with a function `size';
  6026 
  6027 * patterns in case expressions allow tuple patterns as arguments to
  6028 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6029 
  6030 * primrec now also works with type nat;
  6031 
  6032 * recdef: a new declaration form, allows general recursive functions to be
  6033 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6034 
  6035 * the constant for negation has been renamed from "not" to "Not" to
  6036 harmonize with FOL, ZF, LK, etc.;
  6037 
  6038 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6039 infinite lists;
  6040 
  6041 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6042 
  6043 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6044 problems in commutative rings, using axiomatic type classes for + and *;
  6045 
  6046 * more examples in HOL/MiniML and HOL/Auth;
  6047 
  6048 * more default rewrite rules for quantifiers, union/intersection;
  6049 
  6050 * a new constant `arbitrary == @x.False';
  6051 
  6052 * HOLCF/IOA replaces old HOL/IOA;
  6053 
  6054 * HOLCF changes: derived all rules and arities
  6055   + axiomatic type classes instead of classes
  6056   + typedef instead of faking type definitions
  6057   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6058   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6059   + eliminated the types void, one, tr
  6060   + use unit lift and bool lift (with translations) instead of one and tr
  6061   + eliminated blift from Lift3.thy (use Def instead of blift)
  6062   all eliminated rules are derived as theorems --> no visible changes ;
  6063 
  6064 
  6065 *** ZF ***
  6066 
  6067 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6068 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6069 as ZF_cs addSIs [equalityI];
  6070 
  6071 
  6072 
  6073 New in Isabelle94-7 (November 96)
  6074 ---------------------------------
  6075 
  6076 * allowing negative levels (as offsets) in prlev and choplev;
  6077 
  6078 * super-linear speedup for large simplifications;
  6079 
  6080 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6081 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6082 FAIL); can suppress it using the command Delsimps (ex_simps @
  6083 all_simps); De Morgan laws are also now included, by default;
  6084 
  6085 * improved printing of ==>  :  ~:
  6086 
  6087 * new object-logic "Sequents" adds linear logic, while replacing LK
  6088 and Modal (thanks to Sara Kalvala);
  6089 
  6090 * HOL/Auth: correctness proofs for authentication protocols;
  6091 
  6092 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6093 examples on HOL/Auth);
  6094 
  6095 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6096 the rewriter and classical reasoner simultaneously;
  6097 
  6098 * function uresult no longer returns theorems in "standard" format;
  6099 regain previous version by: val uresult = standard o uresult;
  6100 
  6101 
  6102 
  6103 New in Isabelle94-6
  6104 -------------------
  6105 
  6106 * oracles -- these establish an interface between Isabelle and trusted
  6107 external reasoners, which may deliver results as theorems;
  6108 
  6109 * proof objects (in particular record all uses of oracles);
  6110 
  6111 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6112 
  6113 * "constdefs" section in theory files;
  6114 
  6115 * "primrec" section (HOL) no longer requires names;
  6116 
  6117 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6118 
  6119 
  6120 
  6121 New in Isabelle94-5
  6122 -------------------
  6123 
  6124 * reduced space requirements;
  6125 
  6126 * automatic HTML generation from theories;
  6127 
  6128 * theory files no longer require "..." (quotes) around most types;
  6129 
  6130 * new examples, including two proofs of the Church-Rosser theorem;
  6131 
  6132 * non-curried (1994) version of HOL is no longer distributed;
  6133 
  6134 
  6135 
  6136 New in Isabelle94-4
  6137 -------------------
  6138 
  6139 * greatly reduced space requirements;
  6140 
  6141 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6142 
  6143 * searchable theorem database (see the section "Retrieving theorems" on
  6144 page 8 of the Reference Manual);
  6145 
  6146 * new examples, including Grabczewski's monumental case study of the
  6147 Axiom of Choice;
  6148 
  6149 * The previous version of HOL renamed to Old_HOL;
  6150 
  6151 * The new version of HOL (previously called CHOL) uses a curried syntax
  6152 for functions.  Application looks like f a b instead of f(a,b);
  6153 
  6154 * Mutually recursive inductive definitions finally work in HOL;
  6155 
  6156 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6157 translates to the operator "split";
  6158 
  6159 
  6160 
  6161 New in Isabelle94-3
  6162 -------------------
  6163 
  6164 * new infix operator, addss, allowing the classical reasoner to
  6165 perform simplification at each step of its search.  Example:
  6166         fast_tac (cs addss ss)
  6167 
  6168 * a new logic, CHOL, the same as HOL, but with a curried syntax
  6169 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  6170 look like (a,b) instead of <a,b>;
  6171 
  6172 * PLEASE NOTE: CHOL will eventually replace HOL!
  6173 
  6174 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  6175 It translates to the operator "split".  A new theory of integers is available;
  6176 
  6177 * In ZF, integer numerals now denote two's-complement binary integers.
  6178 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  6179 
  6180 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  6181 of the Axiom of Choice;
  6182 
  6183 
  6184 
  6185 New in Isabelle94-2
  6186 -------------------
  6187 
  6188 * Significantly faster resolution;
  6189 
  6190 * the different sections in a .thy file can now be mixed and repeated
  6191 freely;
  6192 
  6193 * Database of theorems for FOL, HOL and ZF.  New
  6194 commands including qed, qed_goal and bind_thm store theorems in the database.
  6195 
  6196 * Simple database queries: return a named theorem (get_thm) or all theorems of
  6197 a given theory (thms_of), or find out what theory a theorem was proved in
  6198 (theory_of_thm);
  6199 
  6200 * Bugs fixed in the inductive definition and datatype packages;
  6201 
  6202 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  6203 and HOL_dup_cs obsolete;
  6204 
  6205 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  6206 have been removed;
  6207 
  6208 * Simpler definition of function space in ZF;
  6209 
  6210 * new results about cardinal and ordinal arithmetic in ZF;
  6211 
  6212 * 'subtype' facility in HOL for introducing new types as subsets of existing
  6213 types;
  6214 
  6215 :mode=text:wrap=hard:maxLineLen=72: