NEWS
author nipkow
Wed Aug 04 11:25:08 2004 +0200 (2004-08-04)
changeset 15106 e8cef6993701
parent 15103 79846e8792eb
child 15119 e5f167042c1d
permissions -rw-r--r--
aded comment
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Provers/quasi.ML:  new transitivity reasoners for transitivity only
    10   and quasi orders.
    11 
    12 * Provers/trancl.ML:  new transitivity reasoner for transitive and
    13   reflexive-transitive closure of relations.
    14 
    15 * Pure: considerably improved version of 'constdefs' command.  Now
    16   performs automatic type-inference of declared constants; additional
    17   support for local structure declarations (cf. locales and HOL
    18   records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    19   to observe strictly sequential dependencies of definitions within a
    20   single 'constdefs' section; moreover, the declared name needs to be
    21   an identifier.  If all fails, consider to fall back on 'consts' and
    22   'defs' separately.
    23 
    24 * Pure: improved indexed syntax and implicit structures.  First of
    25   all, indexed syntax provides a notational device for subscripted
    26   application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    27   expressions.  Secondly, in a local context with structure
    28   declarations, number indexes \<^sub>n or the empty index (default
    29   number 1) refer to a certain fixed variable implicitly; option
    30   show_structs controls printing of implicit structures.  Typical
    31   applications of these concepts involve record types and locales.
    32 
    33 * Pure: clear separation of logical types and nonterminals, where the
    34   latter may only occur in 'syntax' specifications or type
    35   abbreviations.  Before that distinction was only partially
    36   implemented via type class "logic" vs. "{}".  Potential
    37   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
    38   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
    39   specifications may require further adaption (e.g. Cube/Base.thy).
    40 
    41 * Pure: removed obsolete type class "logic", use the top sort {}
    42   instead.  Note that non-logical types should be declared as
    43   'nonterminals' rather than 'types'.  INCOMPATIBILITY for new
    44   object-logic specifications.
    45 
    46 * Pure: print_tac now outputs the goal through the trace channel.
    47 
    48 * Pure: reference Namespace.unique_names included.  If true the
    49   (shortest) namespace-prefix is printed to disambiguate conflicts (as
    50   yet). If false the first entry wins (as during parsing). Default
    51   value is true.
    52 
    53 * Pure: tuned internal renaming of symbolic identifiers -- attach
    54   primes instead of base 26 numbers.
    55 
    56 * Pure/Syntax: inner syntax includes (*(*nested*) comments*).
    57 
    58 * Pure/Syntax: pretty pinter now supports unbreakable blocks,
    59   specified in mixfix annotations as "(00...)".
    60 
    61 * Pure/Syntax: 'advanced' translation functions (parse_translation
    62   etc.) may depend on the signature of the theory context being
    63   presently used for parsing/printing, see also isar-ref manual.
    64 
    65 * Pure/Simplifier: simplification procedures may now take the current
    66   simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
    67   interface), which is very useful for calling the Simplifier
    68   recursively.  Minor INCOMPATIBILITY: the 'prems' argument of
    69   simprocs is gone -- use prems_of_ss on the simpset instead.
    70   Moreover, the low-level mk_simproc no longer applies Logic.varify
    71   internally, to allow for use in a context of fixed variables.
    72 
    73 * Provers: Simplifier and Classical Reasoner now support proof context
    74   dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
    75   components are stored in the theory and patched into the
    76   simpset/claset when used in an Isar proof context.  Context
    77   dependent components are maintained by the following theory
    78   operations:
    79 
    80     Simplifier.add_context_simprocs
    81     Simplifier.del_context_simprocs
    82     Simplifier.set_context_subgoaler
    83     Simplifier.reset_context_subgoaler
    84     Simplifier.add_context_looper
    85     Simplifier.del_context_looper
    86     Simplifier.add_context_unsafe_solver
    87     Simplifier.add_context_safe_solver
    88 
    89     Classical.add_context_safe_wrapper
    90     Classical.del_context_safe_wrapper
    91     Classical.add_context_unsafe_wrapper
    92     Classical.del_context_unsafe_wrapper
    93 
    94   IMPORTANT NOTE: proof tools (methods etc.) need to use
    95   local_simpset_of and local_claset_of to instead of the primitive
    96   Simplifier.get_local_simpset and Classical.get_local_claset,
    97   respectively, in order to see the context dependent fields!
    98 
    99 * Document preparation: antiquotations now provide the option
   100   'locale=NAME' to specify an alternative context used for evaluating
   101   and printing the subsequent argument, as in @{thm [locale=LC]
   102   fold_commute}, for example.
   103 
   104 * Document preparation: commands 'display_drafts' and 'print_drafts'
   105   perform simple output of raw sources.  Only those symbols that do
   106   not require additional LaTeX packages (depending on comments in
   107   isabellesym.sty) are displayed properly, everything else is left
   108   verbatim.  We use isatool display and isatool print as front ends;
   109   these are subject to the DVI_VIEWER and PRINT_COMMAND settings,
   110   respectively.
   111 
   112 * ML: output via the Isabelle channels of writeln/warning/error
   113   etc. is now passed through Output.output, with a hook for arbitrary
   114   transformations depending on the print_mode (cf. Output.add_mode --
   115   the first active mode that provides a output function wins).
   116   Already formatted output may be embedded into further text via
   117   Output.raw; the result of Pretty.string_of/str_of and derived
   118   functions (string_of_term/cterm/thm etc.) is already marked raw to
   119   accommodate easy composition of diagnostic messages etc.
   120   Programmers rarely need to care about Output.output or Output.raw at
   121   all, with some notable exceptions: Output.output is required when
   122   bypassing the standard channels (writeln etc.), or in token
   123   translations to produce properly formatted results; Output.raw is
   124   required when capturing already output material that will eventually
   125   be presented to the user a second time.  For the default print mode,
   126   both Output.output and Output.raw have no effect.
   127 
   128 
   129 *** HOL ***
   130 
   131 * HOL/record: reimplementation of records. Improved scalability for
   132   records with many fields, avoiding performance problems for type
   133   inference. Records are no longer composed of nested field types, but
   134   of nested extension types. Therefore the record type only grows
   135   linear in the number of extensions and not in the number of fields.
   136   The top-level (users) view on records is preserved.  Potential
   137   INCOMPATIBILITY only in strange cases, where the theory depends on
   138   the old record representation. The type generated for a record is
   139   called <record_name>_ext_type.
   140 
   141 * HOL/record: Reference record_quick_and_dirty_sensitive can be
   142   enabled to skip the proofs triggered by a record definition or a
   143   simproc (if quick_and_dirty is enabled). Definitions of large
   144   records can take quite long.
   145 
   146 * HOL/record: "record_upd_simproc" for simplification of multiple
   147   record updates enabled by default.  Moreover, trivial updates are
   148   also removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   149   occasionally, since simplification is more powerful by default.
   150 
   151 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
   152 
   153   syntax (epsilon)
   154     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   155 
   156   The symbol \<some> is displayed as the alternative epsilon of LaTeX
   157   and x-symbol; use option '-m epsilon' to get it actually printed.
   158   Moreover, the mathematically important symbolic identifier
   159   \<epsilon> becomes available as variable, constant etc.
   160 
   161 * HOL/SetInterval: The syntax for open intervals has changed:
   162 
   163   Old         New
   164   {..n(}   -> {..<n}
   165   {)n..}   -> {n<..}
   166   {m..n(}  -> {m..<n}
   167   {)m..n}  -> {m<..n}
   168   {)m..n(} -> {m<..<n}
   169 
   170   The old syntax is still supported but will disappear in the future.
   171   For conversion use the following emacs search and replace patterns:
   172 
   173   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   174   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   175 
   176   They are not perfect but work quite well.
   177 
   178 * HOL: The syntax for 'setsum', summation over finite sets, has changed:
   179 
   180   The syntax for 'setsum (%x. e) A' used to be '\<Sum>x:A. e'
   181   and is now either 'SUM x:A. e' or '\<Sum>x\<in>A. e'.
   182 
   183   There is new syntax for summation over finite sets:
   184 
   185   '\<Sum>x | P. e'    is the same as  'setsum (%x. e) {x. P}'
   186   '\<Sum>x=a..b. e'   is the same as  'setsum (%x. e) {a..b}'
   187   '\<Sum>x=a..<b. e'  is the same as  'setsum (%x. e) {a..<b}'
   188   '\<Sum>x<k. e'      is the same as  'setsum (%x. e) {..<k}'
   189 
   190   Function 'Summation' over nat is gone, its syntax '\<Sum>i<k. e'
   191   now translates into 'setsum' as above.
   192 
   193 * HOL/Simplifier: Is now set up to reason about transitivity chains
   194   involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
   195   provided by Provers/trancl.ML as additional solvers.
   196   INCOMPATIBILITY: old proofs break occasionally as simplification may
   197   now solve more goals than previously.
   198 
   199 
   200 *** HOLCF ***
   201 
   202 * HOLCF: discontinued special version of 'constdefs' (which used to
   203   support continuous functions) in favor of the general Pure one with
   204   full type-inference.
   205 
   206 
   207 *** ZF ***
   208 
   209 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the
   210   First Isomorphism Theorem (on quotienting by the kernel of a
   211   homomorphism).
   212 
   213 * ZF/Simplifier: install second copy of type solver that actually
   214   makes use of TC rules declared to Isar proof contexts (or locales);
   215   the old version is still required for ML proof scripts.
   216 
   217 
   218 
   219 New in Isabelle2004 (April 2004)
   220 --------------------------------
   221 
   222 *** General ***
   223 
   224 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   225   Replaces linorder.ML.
   226 
   227 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   228   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   229   (\<a>...\<z>), are now considered normal letters, and can therefore
   230   be used anywhere where an ASCII letter (a...zA...Z) has until
   231   now. COMPATIBILITY: This obviously changes the parsing of some
   232   terms, especially where a symbol has been used as a binder, say
   233   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   234   as an identifier.  Fix it by inserting a space around former
   235   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   236   existing theory and ML files.
   237 
   238 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   239 
   240 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   241   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   242   a normal (but invisible) letter. For multiple letter subscripts repeat
   243   \<^isub> like this: x\<^isub>1\<^isub>2.
   244 
   245 * Pure: There are now sub-/superscripts that can span more than one
   246   character. Text between \<^bsub> and \<^esub> is set in subscript in
   247   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   248   superscript. The new control characters are not identifier parts.
   249 
   250 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   251   content of "..." to the latex file instead of \isacntrl... . The "..."
   252   may consist of any printable characters excluding the end bracket >.
   253 
   254 * Pure: Using new Isar command "finalconsts" (or the ML functions
   255   Theory.add_finals or Theory.add_finals_i) it is now possible to
   256   declare constants "final", which prevents their being given a definition
   257   later.  It is useful for constants whose behaviour is fixed axiomatically
   258   rather than definitionally, such as the meta-logic connectives.
   259 
   260 * Pure: 'instance' now handles general arities with general sorts
   261   (i.e. intersections of classes),
   262 
   263 * Presentation: generated HTML now uses a CSS style sheet to make layout
   264   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   265   It can be changed to alter the colors/layout of generated pages.
   266 
   267 
   268 *** Isar ***
   269 
   270 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   271   cut_tac, subgoal_tac and thin_tac:
   272   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   273     locales are no longer forced to write Isar proof scripts.
   274     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   275     emulations.
   276   - INCOMPATIBILITY: names of variables to be instantiated may no
   277     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   278     This is consistent with the instantiation attribute "where".
   279 
   280 * Attributes "where" and "of":
   281   - Now take type variables of instantiated theorem into account when reading
   282     the instantiation string.  This fixes a bug that caused instantiated
   283     theorems to have too special types in some circumstances.
   284   - "where" permits explicit instantiations of type variables.
   285 
   286 * Calculation commands "moreover" and "also" no longer interfere with
   287   current facts ("this"), admitting arbitrary combinations with "then"
   288   and derived forms.
   289 
   290 * Locales:
   291   - Goal statements involving the context element "includes" no longer
   292     generate theorems with internal delta predicates (those ending on
   293     "_axioms") in the premise.
   294     Resolve particular premise with <locale>.intro to obtain old form.
   295   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   296     specification and "includes" elements in goal statement.
   297   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   298     [intro?] and [elim?] (respectively) by default.
   299   - Experimental command for instantiation of locales in proof contexts:
   300         instantiate <label>[<attrs>]: <loc>
   301     Instantiates locale <loc> and adds all its theorems to the current context
   302     taking into account their attributes.  Label and attrs are optional
   303     modifiers, like in theorem declarations.  If present, names of
   304     instantiated theorems are qualified with <label>, and the attributes
   305     <attrs> are applied after any attributes these theorems might have already.
   306       If the locale has assumptions, a chained fact of the form
   307     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   308     are derived.  The command does not support old-style locales declared
   309     with "locale (open)".
   310       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   311 
   312 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   313   (Isar) contexts.
   314 
   315 
   316 *** HOL ***
   317 
   318 * Proof import: new image HOL4 contains the imported library from
   319   the HOL4 system with about 2500 theorems. It is imported by
   320   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   321   can be used like any other Isabelle image.  See
   322   HOL/Import/HOL/README for more information.
   323 
   324 * Simplifier:
   325   - Much improved handling of linear and partial orders.
   326     Reasoners for linear and partial orders are set up for type classes
   327     "linorder" and "order" respectively, and are added to the default simpset
   328     as solvers.  This means that the simplifier can build transitivity chains
   329     to solve goals from the assumptions.
   330   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   331     of blast or auto after simplification become unnecessary because the goal
   332     is solved by simplification already.
   333 
   334 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   335     all proved in axiomatic type classes for semirings, rings and fields.
   336 
   337 * Numerics:
   338   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   339     now formalized using the Ring_and_Field theory mentioned above.
   340   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   341     than before, because now they are set up once in a generic manner.
   342   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   343     Look for the general versions in Ring_and_Field (and Power if they concern
   344     exponentiation).
   345 
   346 * Type "rat" of the rational numbers is now available in HOL-Complex.
   347 
   348 * Records:
   349   - Record types are now by default printed with their type abbreviation
   350     instead of the list of all field types. This can be configured via
   351     the reference "print_record_type_abbr".
   352   - Simproc "record_upd_simproc" for simplification of multiple updates added
   353     (not enabled by default).
   354   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   355     EX x. x = sel r to True (not enabled by default).
   356   - Tactic "record_split_simp_tac" to split and simplify records added.
   357 
   358 * 'specification' command added, allowing for definition by
   359   specification.  There is also an 'ax_specification' command that
   360   introduces the new constants axiomatically.
   361 
   362 * arith(_tac) is now able to generate counterexamples for reals as well.
   363 
   364 * HOL-Algebra: new locale "ring" for non-commutative rings.
   365 
   366 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   367   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   368 
   369 * HOL-Matrix: a first theory for matrices in HOL with an application of
   370   matrix theory to linear programming.
   371 
   372 * Unions and Intersections:
   373   The x-symbol output syntax of UN and INT has been changed
   374   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   375   i.e. the index formulae has become a subscript, like in normal math.
   376   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   377   The subscript version is also accepted as input syntax.
   378 
   379 * Unions and Intersections over Intervals:
   380   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   381   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   382   like in normal math, and corresponding versions for < and for intersection.
   383 
   384 * ML: the legacy theory structures Int and List have been removed. They had
   385   conflicted with ML Basis Library structures having the same names.
   386 
   387 * 'refute' command added to search for (finite) countermodels.  Only works
   388   for a fragment of HOL.  The installation of an external SAT solver is
   389   highly recommended.  See "HOL/Refute.thy" for details.
   390 
   391 * 'quickcheck' command: Allows to find counterexamples by evaluating
   392   formulae under an assignment of free variables to random values.
   393   In contrast to 'refute', it can deal with inductive datatypes,
   394   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   395   for examples.
   396 
   397 
   398 *** HOLCF ***
   399 
   400 * Streams now come with concatenation and are part of the HOLCF image
   401 
   402 
   403 
   404 New in Isabelle2003 (May 2003)
   405 ------------------------------
   406 
   407 *** General ***
   408 
   409 * Provers/simplifier:
   410 
   411   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   412     Assumptions are now subject to complete mutual simplification,
   413     not just from left to right. The simplifier now preserves
   414     the order of assumptions.
   415 
   416     Potential INCOMPATIBILITY:
   417 
   418     -- simp sometimes diverges where the old version did
   419        not, e.g. invoking simp on the goal
   420 
   421         [| P (f x); y = x; f x = f y |] ==> Q
   422 
   423        now gives rise to the infinite reduction sequence
   424 
   425         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   426 
   427        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   428        kind of problem.
   429 
   430     -- Tactics combining classical reasoner and simplification (such as auto)
   431        are also affected by this change, because many of them rely on
   432        simp. They may sometimes diverge as well or yield a different numbers
   433        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   434        in case of problems. Sometimes subsequent calls to the classical
   435        reasoner will fail because a preceeding call to the simplifier too
   436        eagerly simplified the goal, e.g. deleted redundant premises.
   437 
   438   - The simplifier trace now shows the names of the applied rewrite rules
   439 
   440   - You can limit the number of recursive invocations of the simplifier
   441     during conditional rewriting (where the simplifie tries to solve the
   442     conditions before applying the rewrite rule):
   443     ML "simp_depth_limit := n"
   444     where n is an integer. Thus you can force termination where previously
   445     the simplifier would diverge.
   446 
   447   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   448 
   449   - No longer aborts on failed congruence proof.  Instead, the
   450     congruence is ignored.
   451 
   452 * Pure: New generic framework for extracting programs from constructive
   453   proofs. See HOL/Extraction.thy for an example instantiation, as well
   454   as HOL/Extraction for some case studies.
   455 
   456 * Pure: The main goal of the proof state is no longer shown by default, only
   457 the subgoals. This behaviour is controlled by a new flag.
   458    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   459 (ML: Proof.show_main_goal).
   460 
   461 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   462 rules whose conclusion matches subgoal 1:
   463       PG menu: Isabelle/Isar -> Show me -> matching rules
   464 The rules are ordered by how closely they match the subgoal.
   465 In particular, rules that solve a subgoal outright are displayed first
   466 (or rather last, the way they are printed).
   467 (ML: ProofGeneral.print_intros())
   468 
   469 * Pure: New flag trace_unify_fail causes unification to print
   470 diagnostic information (PG: in trace buffer) when it fails. This is
   471 useful for figuring out why single step proofs like rule, erule or
   472 assumption failed.
   473 
   474 * Pure: Locale specifications now produce predicate definitions
   475 according to the body of text (covering assumptions modulo local
   476 definitions); predicate "loc_axioms" covers newly introduced text,
   477 while "loc" is cumulative wrt. all included locale expressions; the
   478 latter view is presented only on export into the global theory
   479 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   480 on the old view without predicates;
   481 
   482 * Pure: predefined locales "var" and "struct" are useful for sharing
   483 parameters (as in CASL, for example); just specify something like
   484 ``var x + var y + struct M'' as import;
   485 
   486 * Pure: improved thms_containing: proper indexing of facts instead of
   487 raw theorems; check validity of results wrt. current name space;
   488 include local facts of proof configuration (also covers active
   489 locales), cover fixed variables in index; may use "_" in term
   490 specification; an optional limit for the number of printed facts may
   491 be given (the default is 40);
   492 
   493 * Pure: disallow duplicate fact bindings within new-style theory files
   494 (batch-mode only);
   495 
   496 * Provers: improved induct method: assumptions introduced by case
   497 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   498 the goal statement); "foo" still refers to all facts collectively;
   499 
   500 * Provers: the function blast.overloaded has been removed: all constants
   501 are regarded as potentially overloaded, which improves robustness in exchange
   502 for slight decrease in efficiency;
   503 
   504 * Provers/linorder: New generic prover for transitivity reasoning over
   505 linear orders.  Note: this prover is not efficient!
   506 
   507 * Isar: preview of problems to finish 'show' now produce an error
   508 rather than just a warning (in interactive mode);
   509 
   510 
   511 *** HOL ***
   512 
   513 * arith(_tac)
   514 
   515  - Produces a counter example if it cannot prove a goal.
   516    Note that the counter example may be spurious if the goal is not a formula
   517    of quantifier-free linear arithmetic.
   518    In ProofGeneral the counter example appears in the trace buffer.
   519 
   520  - Knows about div k and mod k where k is a numeral of type nat or int.
   521 
   522  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   523    linear arithmetic fails. This takes account of quantifiers and divisibility.
   524    Presburger arithmetic can also be called explicitly via presburger(_tac).
   525 
   526 * simp's arithmetic capabilities have been enhanced a bit: it now
   527 takes ~= in premises into account (by performing a case split);
   528 
   529 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   530 are distributed over a sum of terms;
   531 
   532 * New tactic "trans_tac" and method "trans" instantiate
   533 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   534 "<=", "<" and "=").
   535 
   536 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   537 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   538 
   539 * 'typedef' command has new option "open" to suppress the set
   540 definition;
   541 
   542 * functions Min and Max on finite sets have been introduced (theory
   543 Finite_Set);
   544 
   545 * attribute [symmetric] now works for relations as well; it turns
   546 (x,y) : R^-1 into (y,x) : R, and vice versa;
   547 
   548 * induct over a !!-quantified statement (say !!x1..xn):
   549   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   550 
   551 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   552 %x. None. Warning: empty_def now refers to the previously hidden definition
   553 of the empty set.
   554 
   555 * Algebra: formalization of classical algebra.  Intended as base for
   556 any algebraic development in Isabelle.  Currently covers group theory
   557 (up to Sylow's theorem) and ring theory (Universal Property of
   558 Univariate Polynomials).  Contributions welcome;
   559 
   560 * GroupTheory: deleted, since its material has been moved to Algebra;
   561 
   562 * Complex: new directory of the complex numbers with numeric constants,
   563 nonstandard complex numbers, and some complex analysis, standard and
   564 nonstandard (Jacques Fleuriot);
   565 
   566 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   567 
   568 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   569 Fleuriot);
   570 
   571 * Real/HahnBanach: updated and adapted to locales;
   572 
   573 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   574 Gray and Kramer);
   575 
   576 * UNITY: added the Meier-Sanders theory of progress sets;
   577 
   578 * MicroJava: bytecode verifier and lightweight bytecode verifier
   579 as abstract algorithms, instantiated to the JVM;
   580 
   581 * Bali: Java source language formalization. Type system, operational
   582 semantics, axiomatic semantics. Supported language features:
   583 classes, interfaces, objects,virtual methods, static methods,
   584 static/instance fields, arrays, access modifiers, definite
   585 assignment, exceptions.
   586 
   587 
   588 *** ZF ***
   589 
   590 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   591 universe, etc.);
   592 
   593 * Main ZF: virtually all theories converted to new-style format;
   594 
   595 
   596 *** ML ***
   597 
   598 * Pure: Tactic.prove provides sane interface for internal proofs;
   599 omits the infamous "standard" operation, so this is more appropriate
   600 than prove_goalw_cterm in many situations (e.g. in simprocs);
   601 
   602 * Pure: improved error reporting of simprocs;
   603 
   604 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   605 up simprocs;
   606 
   607 
   608 *** Document preparation ***
   609 
   610 * uses \par instead of \\ for line breaks in theory text. This may
   611 shift some page breaks in large documents. To get the old behaviour
   612 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   613 
   614 * minimized dependencies of isabelle.sty and isabellesym.sty on
   615 other packages
   616 
   617 * \<euro> now needs package babel/greek instead of marvosym (which
   618 broke \Rightarrow)
   619 
   620 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   621 textcomp package)
   622 
   623 
   624 
   625 New in Isabelle2002 (March 2002)
   626 --------------------------------
   627 
   628 *** Document preparation ***
   629 
   630 * greatly simplified document preparation setup, including more
   631 graceful interpretation of isatool usedir -i/-d/-D options, and more
   632 instructive isatool mkdir; users should basically be able to get
   633 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   634 users may run a separate document processing stage manually like this:
   635 "isatool usedir -D output HOL Test && isatool document Test/output";
   636 
   637 * theory dependency graph may now be incorporated into documents;
   638 isatool usedir -g true will produce session_graph.eps/.pdf for use
   639 with \includegraphics of LaTeX;
   640 
   641 * proper spacing of consecutive markup elements, especially text
   642 blocks after section headings;
   643 
   644 * support bold style (for single symbols only), input syntax is like
   645 this: "\<^bold>\<alpha>" or "\<^bold>A";
   646 
   647 * \<bullet> is now output as bold \cdot by default, which looks much
   648 better in printed text;
   649 
   650 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   651 note that these symbols are currently unavailable in Proof General /
   652 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   653 
   654 * isatool latex no longer depends on changed TEXINPUTS, instead
   655 isatool document copies the Isabelle style files to the target
   656 location;
   657 
   658 
   659 *** Isar ***
   660 
   661 * Pure/Provers: improved proof by cases and induction;
   662   - 'case' command admits impromptu naming of parameters (such as
   663     "case (Suc n)");
   664   - 'induct' method divinates rule instantiation from the inductive
   665     claim; no longer requires excessive ?P bindings for proper
   666     instantiation of cases;
   667   - 'induct' method properly enumerates all possibilities of set/type
   668     rules; as a consequence facts may be also passed through *type*
   669     rules without further ado;
   670   - 'induct' method now derives symbolic cases from the *rulified*
   671     rule (before it used to rulify cases stemming from the internal
   672     atomized version); this means that the context of a non-atomic
   673     statement becomes is included in the hypothesis, avoiding the
   674     slightly cumbersome show "PROP ?case" form;
   675   - 'induct' may now use elim-style induction rules without chaining
   676     facts, using ``missing'' premises from the goal state; this allows
   677     rules stemming from inductive sets to be applied in unstructured
   678     scripts, while still benefitting from proper handling of non-atomic
   679     statements; NB: major inductive premises need to be put first, all
   680     the rest of the goal is passed through the induction;
   681   - 'induct' proper support for mutual induction involving non-atomic
   682     rule statements (uses the new concept of simultaneous goals, see
   683     below);
   684   - append all possible rule selections, but only use the first
   685     success (no backtracking);
   686   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   687   - undeclared rule case names default to numbers 1, 2, 3, ...;
   688   - added 'print_induct_rules' (covered by help item in recent Proof
   689     General versions);
   690   - moved induct/cases attributes to Pure, methods to Provers;
   691   - generic method setup instantiated for FOL and HOL;
   692 
   693 * Pure: support multiple simultaneous goal statements, for example
   694 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   695 meta-level mechanism, this acts as if several individual goals had
   696 been stated separately; in particular common proof methods need to be
   697 repeated in order to cover all claims; note that a single elimination
   698 step is *not* sufficient to establish the two conjunctions, so this
   699 fails:
   700 
   701   assume "A & B" then have A and B ..   (*".." fails*)
   702 
   703 better use "obtain" in situations as above; alternative refer to
   704 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   705 
   706 * Pure: proper integration with ``locales''; unlike the original
   707 version by Florian Kammüller, Isar locales package high-level proof
   708 contexts rather than raw logical ones (e.g. we admit to include
   709 attributes everywhere); operations on locales include merge and
   710 rename; support for implicit arguments (``structures''); simultaneous
   711 type-inference over imports and text; see also HOL/ex/Locales.thy for
   712 some examples;
   713 
   714 * Pure: the following commands have been ``localized'', supporting a
   715 target locale specification "(in name)": 'lemma', 'theorem',
   716 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   717 stored both within the locale and at the theory level (exported and
   718 qualified by the locale name);
   719 
   720 * Pure: theory goals may now be specified in ``long'' form, with
   721 ad-hoc contexts consisting of arbitrary locale elements. for example
   722 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   723 definitions may be given, too); the result is a meta-level rule with
   724 the context elements being discharged in the obvious way;
   725 
   726 * Pure: new proof command 'using' allows to augment currently used
   727 facts after a goal statement ('using' is syntactically analogous to
   728 'apply', but acts on the goal's facts only); this allows chained facts
   729 to be separated into parts given before and after a claim, as in
   730 ``from a and b have C using d and e <proof>'';
   731 
   732 * Pure: renamed "antecedent" case to "rule_context";
   733 
   734 * Pure: new 'judgment' command records explicit information about the
   735 object-logic embedding (used by several tools internally); no longer
   736 use hard-wired "Trueprop";
   737 
   738 * Pure: added 'corollary' command;
   739 
   740 * Pure: fixed 'token_translation' command;
   741 
   742 * Pure: removed obsolete 'exported' attribute;
   743 
   744 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   745 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   746 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   747 
   748 * Pure: method 'atomize' presents local goal premises as object-level
   749 statements (atomic meta-level propositions); setup controlled via
   750 rewrite rules declarations of 'atomize' attribute; example
   751 application: 'induct' method with proper rule statements in improper
   752 proof *scripts*;
   753 
   754 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   755 now consider the syntactic context of assumptions, giving a better
   756 chance to get type-inference of the arguments right (this is
   757 especially important for locales);
   758 
   759 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   760 mode;
   761 
   762 * Pure/obtain: the formal conclusion "thesis", being marked as
   763 ``internal'', may no longer be reference directly in the text;
   764 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   765 situations;
   766 
   767 * Pure: generic 'sym' attribute which declares a rule both as pure
   768 'elim?' and for the 'symmetric' operation;
   769 
   770 * Pure: marginal comments ``--'' may now occur just anywhere in the
   771 text; the fixed correlation with particular command syntax has been
   772 discontinued;
   773 
   774 * Pure: new method 'rules' is particularly well-suited for proof
   775 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   776 but often produces more compact proof terms with less detours;
   777 
   778 * Pure/Provers/classical: simplified integration with pure rule
   779 attributes and methods; the classical "intro?/elim?/dest?"
   780 declarations coincide with the pure ones; the "rule" method no longer
   781 includes classically swapped intros; "intro" and "elim" methods no
   782 longer pick rules from the context; also got rid of ML declarations
   783 AddXIs/AddXEs/AddXDs; all of this has some potential for
   784 INCOMPATIBILITY;
   785 
   786 * Provers/classical: attribute 'swapped' produces classical inversions
   787 of introduction rules;
   788 
   789 * Provers/simplifier: 'simplified' attribute may refer to explicit
   790 rules instead of full simplifier context; 'iff' attribute handles
   791 conditional rules;
   792 
   793 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   794 
   795 * HOL: 'recdef' now fails on unfinished automated proofs, use
   796 "(permissive)" option to recover old behavior;
   797 
   798 * HOL: 'inductive' no longer features separate (collective) attributes
   799 for 'intros' (was found too confusing);
   800 
   801 * HOL: properly declared induction rules less_induct and
   802 wf_induct_rule;
   803 
   804 
   805 *** HOL ***
   806 
   807 * HOL: moved over to sane numeral syntax; the new policy is as
   808 follows:
   809 
   810   - 0 and 1 are polymorphic constants, which are defined on any
   811   numeric type (nat, int, real etc.);
   812 
   813   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   814   binary representation internally;
   815 
   816   - type nat has special constructor Suc, and generally prefers Suc 0
   817   over 1::nat and Suc (Suc 0) over 2::nat;
   818 
   819 This change may cause significant problems of INCOMPATIBILITY; here
   820 are some hints on converting existing sources:
   821 
   822   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   823   entities, so expressions involving "-" (unary or binary minus) need
   824   to be spaced properly;
   825 
   826   - existing occurrences of "1" may need to be constraint "1::nat" or
   827   even replaced by Suc 0; similar for old "2";
   828 
   829   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   830 
   831   - remove all special provisions on numerals in proofs;
   832 
   833 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   834 representation (depends on bin_arith_simps in the default context);
   835 
   836 * HOL: symbolic syntax for x^2 (numeral 2);
   837 
   838 * HOL: the class of all HOL types is now called "type" rather than
   839 "term"; INCOMPATIBILITY, need to adapt references to this type class
   840 in axclass/classes, instance/arities, and (usually rare) occurrences
   841 in typings (of consts etc.); internally the class is called
   842 "HOL.type", ML programs should refer to HOLogic.typeS;
   843 
   844 * HOL/record package improvements:
   845   - new derived operations "fields" to build a partial record section,
   846     "extend" to promote a fixed record to a record scheme, and
   847     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   848     declared as simp by default;
   849   - shared operations ("more", "fields", etc.) now need to be always
   850     qualified) --- potential INCOMPATIBILITY;
   851   - removed "make_scheme" operations (use "make" with "extend") --
   852     INCOMPATIBILITY;
   853   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   854   - provides cases/induct rules for use with corresponding Isar
   855     methods (for concrete records, record schemes, concrete more
   856     parts, and schematic more parts -- in that order);
   857   - internal definitions directly based on a light-weight abstract
   858     theory of product types over typedef rather than datatype;
   859 
   860 * HOL: generic code generator for generating executable ML code from
   861 specifications; specific support for HOL constructs such as inductive
   862 datatypes and sets, as well as recursive functions; can be invoked
   863 via 'generate_code' theory section;
   864 
   865 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   866 
   867 * HOL: consolidated and renamed several theories.  In particular:
   868         Ord.thy has been absorbed into HOL.thy
   869         String.thy has been absorbed into List.thy
   870 
   871 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   872 (beware of argument permutation!);
   873 
   874 * HOL: linorder_less_split superseded by linorder_cases;
   875 
   876 * HOL/List: "nodups" renamed to "distinct";
   877 
   878 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   879 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   880   - Ex_def has changed, now need to use some_eq_ex
   881 
   882 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   883 in this (rare) case use:
   884 
   885   delSWrapper "split_all_tac"
   886   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   887 
   888 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   889 MAY FAIL;
   890 
   891 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   892 Isabelle's type classes, ^ on functions and relations has too general
   893 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   894 necessary to attach explicit type constraints;
   895 
   896 * HOL/Relation: the prefix name of the infix "O" has been changed from
   897 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   898 renamed accordingly (eg "compI" -> "rel_compI").
   899 
   900 * HOL: syntax translations now work properly with numerals and records
   901 expressions;
   902 
   903 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   904 of "lam" -- INCOMPATIBILITY;
   905 
   906 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   907 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   908 renamed "Product_Type.unit";
   909 
   910 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   911 
   912 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   913 the "cases" method);
   914 
   915 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   916 Florian Kammüller);
   917 
   918 * HOL/IMP: updated and converted to new-style theory format; several
   919 parts turned into readable document, with proper Isar proof texts and
   920 some explanations (by Gerwin Klein);
   921 
   922 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   923 
   924 * HOL-Hyperreal is now a logic image;
   925 
   926 
   927 *** HOLCF ***
   928 
   929 * Isar: consts/constdefs supports mixfix syntax for continuous
   930 operations;
   931 
   932 * Isar: domain package adapted to new-style theory format, e.g. see
   933 HOLCF/ex/Dnat.thy;
   934 
   935 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   936 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   937 lift.induct_tac, always use UU instead of Undef;
   938 
   939 * HOLCF/IMP: updated and converted to new-style theory;
   940 
   941 
   942 *** ZF ***
   943 
   944 * Isar: proper integration of logic-specific tools and packages,
   945 including theory commands '(co)inductive', '(co)datatype',
   946 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   947 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   948 
   949 * theory Main no longer includes AC; for the Axiom of Choice, base
   950 your theory on Main_ZFC;
   951 
   952 * the integer library now covers quotients and remainders, with many
   953 laws relating division to addition, multiplication, etc.;
   954 
   955 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   956 typeless version of the formalism;
   957 
   958 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   959 format;
   960 
   961 * ZF/Induct: new directory for examples of inductive definitions,
   962 including theory Multiset for multiset orderings; converted to
   963 new-style theory format;
   964 
   965 * ZF: many new theorems about lists, ordinals, etc.;
   966 
   967 
   968 *** General ***
   969 
   970 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   971 variable proof controls level of detail: 0 = no proofs (only oracle
   972 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   973 also ref manual for further ML interfaces;
   974 
   975 * Pure/axclass: removed obsolete ML interface
   976 goal_subclass/goal_arity;
   977 
   978 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   979 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   980 separate tokens, so expressions involving minus need to be spaced
   981 properly;
   982 
   983 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   984 rather than "infixl" or "infixr";
   985 
   986 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   987 sort constraint specifications in type inference; e.g. "x::_::foo"
   988 ensures that the type of "x" is of sort "foo" (but not necessarily a
   989 type variable);
   990 
   991 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   992 control output of nested => (types); the default behavior is
   993 "type_brackets";
   994 
   995 * Pure/syntax: builtin parse translation for "_constify" turns valued
   996 tokens into AST constants;
   997 
   998 * Pure/syntax: prefer later declarations of translations and print
   999 translation functions; potential INCOMPATIBILITY: need to reverse
  1000 multiple declarations for same syntax element constant;
  1001 
  1002 * Pure/show_hyps reset by default (in accordance to existing Isar
  1003 practice);
  1004 
  1005 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1006 addSafter;
  1007 
  1008 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1009 as well;
  1010 
  1011 * system: tested support for MacOS X; should be able to get Isabelle +
  1012 Proof General to work in a plain Terminal after installing Poly/ML
  1013 (e.g. from the Isabelle distribution area) and GNU bash alone
  1014 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1015 support requires further installations, e.g. from
  1016 http://fink.sourceforge.net/);
  1017 
  1018 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1019 
  1020 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1021 of 40 MB), cf. ML_OPTIONS;
  1022 
  1023 * system: Proof General keywords specification is now part of the
  1024 Isabelle distribution (see etc/isar-keywords.el);
  1025 
  1026 * system: support for persistent Proof General sessions (refrain from
  1027 outdating all loaded theories on startup); user may create writable
  1028 logic images like this: ``isabelle -q HOL Test'';
  1029 
  1030 * system: smart selection of Isabelle process versus Isabelle
  1031 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1032 run both "isabelle" and "Isabelle" even if file names are badly
  1033 damaged (executable inspects the case of the first letter of its own
  1034 name); added separate "isabelle-process" and "isabelle-interface";
  1035 
  1036 * system: refrain from any attempt at filtering input streams; no
  1037 longer support ``8bit'' encoding of old isabelle font, instead proper
  1038 iso-latin characters may now be used; the related isatools
  1039 "symbolinput" and "nonascii" have disappeared as well;
  1040 
  1041 * system: removed old "xterm" interface (the print modes "xterm" and
  1042 "xterm_color" are still available for direct use in a suitable
  1043 terminal);
  1044 
  1045 
  1046 
  1047 New in Isabelle99-2 (February 2001)
  1048 -----------------------------------
  1049 
  1050 *** Overview of INCOMPATIBILITIES ***
  1051 
  1052 * HOL: please note that theories in the Library and elsewhere often use the
  1053 new-style (Isar) format; to refer to their theorems in an ML script you must
  1054 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1055 
  1056 * HOL: inductive package no longer splits induction rule aggressively,
  1057 but only as far as specified by the introductions given; the old
  1058 format may be recovered via ML function complete_split_rule or attribute
  1059 'split_rule (complete)';
  1060 
  1061 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1062 gfp_Tarski to gfp_unfold;
  1063 
  1064 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1065 
  1066 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1067 relation); infix "^^" has been renamed "``"; infix "``" has been
  1068 renamed "`"; "univalent" has been renamed "single_valued";
  1069 
  1070 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1071 operation;
  1072 
  1073 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1074 
  1075 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1076 
  1077 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1078 consequence, it is no longer monotonic wrt. the local goal context
  1079 (which is now passed through the inductive cases);
  1080 
  1081 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1082 \<gg> to \<ggreater>;
  1083 
  1084 
  1085 *** Document preparation ***
  1086 
  1087 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1088 available: are "it" for near math-mode best-style output, "sl" for
  1089 slanted text style, and "tt" for plain type-writer; if no
  1090 \isabellestyle command is given, output is according to slanted
  1091 type-writer);
  1092 
  1093 * support sub/super scripts (for single symbols only), input syntax is
  1094 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1095 
  1096 * some more standard symbols; see Appendix A of the system manual for
  1097 the complete list of symbols defined in isabellesym.sty;
  1098 
  1099 * improved isabelle style files; more abstract symbol implementation
  1100 (should now use \isamath{...} and \isatext{...} in custom symbol
  1101 definitions);
  1102 
  1103 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1104 state; Note that presentation of goal states does not conform to
  1105 actual human-readable proof documents.  Please do not include goal
  1106 states into document output unless you really know what you are doing!
  1107 
  1108 * proper indentation of antiquoted output with proportional LaTeX
  1109 fonts;
  1110 
  1111 * no_document ML operator temporarily disables LaTeX document
  1112 generation;
  1113 
  1114 * isatool unsymbolize tunes sources for plain ASCII communication;
  1115 
  1116 
  1117 *** Isar ***
  1118 
  1119 * Pure: Isar now suffers initial goal statements to contain unbound
  1120 schematic variables (this does not conform to actual readable proof
  1121 documents, due to unpredictable outcome and non-compositional proof
  1122 checking); users who know what they are doing may use schematic goals
  1123 for Prolog-style synthesis of proven results;
  1124 
  1125 * Pure: assumption method (an implicit finishing) now handles actual
  1126 rules as well;
  1127 
  1128 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1129 initial goal, declare "that" only as Pure intro (only for single
  1130 steps); the "that" rule assumption may now be involved in implicit
  1131 finishing, thus ".." becomes a feasible for trivial obtains;
  1132 
  1133 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1134 instance proofs may be performed by "..";
  1135 
  1136 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1137 statements as well;
  1138 
  1139 * Pure: more robust selection of calculational rules;
  1140 
  1141 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1142 rule (as well as the assumption rule);
  1143 
  1144 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1145 lemmas, using the graph browser tool;
  1146 
  1147 * Pure: predict failure of "show" in interactive mode;
  1148 
  1149 * Pure: 'thms_containing' now takes actual terms as arguments;
  1150 
  1151 * HOL: improved method 'induct' --- now handles non-atomic goals
  1152 (potential INCOMPATIBILITY); tuned error handling;
  1153 
  1154 * HOL: cases and induct rules now provide explicit hints about the
  1155 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1156 any remaining facts are inserted into the goal verbatim;
  1157 
  1158 * HOL: local contexts (aka cases) may now contain term bindings as
  1159 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1160 the result to be shown in each case;
  1161 
  1162 * HOL: added 'recdef_tc' command;
  1163 
  1164 * isatool convert assists in eliminating legacy ML scripts;
  1165 
  1166 
  1167 *** HOL ***
  1168 
  1169 * HOL/Library: a collection of generic theories to be used together
  1170 with main HOL; the theory loader path already includes this directory
  1171 by default; the following existing theories have been moved here:
  1172 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1173 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1174 
  1175 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1176 modelling and verification task performed in Isabelle/HOL +
  1177 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1178 
  1179 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1180 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1181 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1182 'domain', this makes the theory consistent with mathematical
  1183 literature;
  1184 
  1185 * HOL basics: added overloaded operations "inverse" and "divide"
  1186 (infix "/"), syntax for generic "abs" operation, generic summation
  1187 operator \<Sum>;
  1188 
  1189 * HOL/typedef: simplified package, provide more useful rules (see also
  1190 HOL/subset.thy);
  1191 
  1192 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1193 now expressed as a proper nested rule (old-style tactic scripts may
  1194 require atomize_strip_tac to cope with non-atomic premises);
  1195 
  1196 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1197 to "split_conv" (old name still available for compatibility);
  1198 
  1199 * HOL: improved concrete syntax for strings (e.g. allows translation
  1200 rules with string literals);
  1201 
  1202 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1203  and Fleuriot's mechanization of analysis, including the transcendental
  1204  functions for the reals;
  1205 
  1206 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1207 
  1208 
  1209 *** CTT ***
  1210 
  1211 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1212 "lam" is displayed as TWO lambda-symbols
  1213 
  1214 * CTT: theory Main now available, containing everything (that is, Bool
  1215 and Arith);
  1216 
  1217 
  1218 *** General ***
  1219 
  1220 * Pure: the Simplifier has been implemented properly as a derived rule
  1221 outside of the actual kernel (at last!); the overall performance
  1222 penalty in practical applications is about 50%, while reliability of
  1223 the Isabelle inference kernel has been greatly improved;
  1224 
  1225 * print modes "brackets" and "no_brackets" control output of nested =>
  1226 (types) and ==> (props); the default behaviour is "brackets";
  1227 
  1228 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1229 as assumptions as well;
  1230 
  1231 * system: support Poly/ML 4.0;
  1232 
  1233 * system: isatool install handles KDE version 1 or 2;
  1234 
  1235 
  1236 
  1237 New in Isabelle99-1 (October 2000)
  1238 ----------------------------------
  1239 
  1240 *** Overview of INCOMPATIBILITIES ***
  1241 
  1242 * HOL: simplification of natural numbers is much changed; to partly
  1243 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1244 issue the following ML commands:
  1245 
  1246   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1247   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1248 
  1249 * HOL: simplification no longer dives into case-expressions; this is
  1250 controlled by "t.weak_case_cong" for each datatype t;
  1251 
  1252 * HOL: nat_less_induct renamed to less_induct;
  1253 
  1254 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1255 fixsome to patch .thy and .ML sources automatically;
  1256 
  1257   select_equality  -> some_equality
  1258   select_eq_Ex     -> some_eq_ex
  1259   selectI2EX       -> someI2_ex
  1260   selectI2         -> someI2
  1261   selectI          -> someI
  1262   select1_equality -> some1_equality
  1263   Eps_sym_eq       -> some_sym_eq_trivial
  1264   Eps_eq           -> some_eq_trivial
  1265 
  1266 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1267 
  1268 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1269 instead);
  1270 
  1271 * HOL: the recursion equations generated by 'recdef' are now called
  1272 f.simps instead of f.rules;
  1273 
  1274 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1275 
  1276 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1277 sometimes be needed;
  1278 
  1279 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1280 
  1281 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1282 
  1283 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1284 product is now "<*>" instead of "Times"; the lexicographic product is
  1285 now "<*lex*>" instead of "**";
  1286 
  1287 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1288 of main HOL, but was unused); better use HOL's datatype package;
  1289 
  1290 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1291 the old syntax may be recovered as follows:
  1292 
  1293   syntax (symbols)
  1294     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1295       (infixl "\\<oplus>" 100)
  1296 
  1297 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1298 
  1299 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1300 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1301 internally;
  1302 
  1303 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1304 changed from A/r to A//r;
  1305 
  1306 * ZF: new treatment of arithmetic (nat & int) may break some old
  1307 proofs;
  1308 
  1309 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1310 rulify -> rule_format, elimify -> elim_format, ...);
  1311 
  1312 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1313 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1314 should have to change intro!! to intro? only); replaced "delrule" by
  1315 "rule del";
  1316 
  1317 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1318 
  1319 * Provers: strengthened force_tac by using new first_best_tac;
  1320 
  1321 * LaTeX document preparation: several changes of isabelle.sty (see
  1322 lib/texinputs);
  1323 
  1324 
  1325 *** Document preparation ***
  1326 
  1327 * formal comments (text blocks etc.) in new-style theories may now
  1328 contain antiquotations of thm/prop/term/typ/text to be presented
  1329 according to latex print mode; concrete syntax is like this:
  1330 @{term[show_types] "f(x) = a + x"};
  1331 
  1332 * isatool mkdir provides easy setup of Isabelle session directories,
  1333 including proper document sources;
  1334 
  1335 * generated LaTeX sources are now deleted after successful run
  1336 (isatool document -c); may retain a copy somewhere else via -D option
  1337 of isatool usedir;
  1338 
  1339 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1340 style files, achieving self-contained LaTeX sources and simplifying
  1341 LaTeX debugging;
  1342 
  1343 * old-style theories now produce (crude) LaTeX output as well;
  1344 
  1345 * browser info session directories are now self-contained (may be put
  1346 on WWW server seperately); improved graphs of nested sessions; removed
  1347 graph for 'all sessions';
  1348 
  1349 * several improvements in isabelle style files; \isabellestyle{it}
  1350 produces fake math mode output; \isamarkupheader is now \section by
  1351 default; see lib/texinputs/isabelle.sty etc.;
  1352 
  1353 
  1354 *** Isar ***
  1355 
  1356 * Isar/Pure: local results and corresponding term bindings are now
  1357 subject to Hindley-Milner polymorphism (similar to ML); this
  1358 accommodates incremental type-inference very nicely;
  1359 
  1360 * Isar/Pure: new derived language element 'obtain' supports
  1361 generalized existence reasoning;
  1362 
  1363 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1364 support accumulation of results, without applying any rules yet;
  1365 useful to collect intermediate results without explicit name
  1366 references, and for use with transitivity rules with more than 2
  1367 premises;
  1368 
  1369 * Isar/Pure: scalable support for case-analysis type proofs: new
  1370 'case' language element refers to local contexts symbolically, as
  1371 produced by certain proof methods; internally, case names are attached
  1372 to theorems as "tags";
  1373 
  1374 * Isar/Pure: theory command 'hide' removes declarations from
  1375 class/type/const name spaces;
  1376 
  1377 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1378 indicate potential overloading;
  1379 
  1380 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1381 
  1382 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1383 "{a,b,c}" instead of {a,b,c};
  1384 
  1385 * Isar/Pure now provides its own version of intro/elim/dest
  1386 attributes; useful for building new logics, but beware of confusion
  1387 with the version in Provers/classical;
  1388 
  1389 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1390 case name 'antecedent';
  1391 
  1392 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1393 to the current context is now done automatically);
  1394 
  1395 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1396 for definining proof methods in ML;
  1397 
  1398 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1399 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1400 most cases, one should have to change intro!! to intro? only);
  1401 replaced "delrule" by "rule del";
  1402 
  1403 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1404 'symmetric' attribute (the latter supercedes [RS sym]);
  1405 
  1406 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1407 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1408 well (including splits);
  1409 
  1410 * Isar/Provers: Simplifier and Classical methods now support all kind
  1411 of modifiers used in the past, including 'cong', 'iff', etc.
  1412 
  1413 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1414 of Simplifier and Classical reasoner);
  1415 
  1416 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1417 now support named cases; major packages (inductive, datatype, primrec,
  1418 recdef) support case names and properly name parameters;
  1419 
  1420 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1421 monotonicity conditions are extracted to be proven at end of
  1422 calculations;
  1423 
  1424 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1425 method anyway;
  1426 
  1427 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1428 split_if split_if_asm; datatype package provides theorems foo.splits =
  1429 foo.split foo.split_asm for each datatype;
  1430 
  1431 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1432 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1433 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1434 use "(cases (simplified))" method in proper proof texts);
  1435 
  1436 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1437 
  1438 * Isar: names of theorems etc. may be natural numbers as well;
  1439 
  1440 * Isar: 'pr' command: optional arguments for goals_limit and
  1441 ProofContext.prems_limit; no longer prints theory contexts, but only
  1442 proof states;
  1443 
  1444 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1445 additional print modes to be specified; e.g. "pr(latex)" will print
  1446 proof state according to the Isabelle LaTeX style;
  1447 
  1448 * Isar: improved support for emulating tactic scripts, including proof
  1449 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1450 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1451 (for HOL datatypes);
  1452 
  1453 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1454 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1455 'proof method scripts' have to be in depth-first order;
  1456 
  1457 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1458 
  1459 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1460 should instead use individual commands for printing items
  1461 (print_commands, print_methods etc.);
  1462 
  1463 * Isar: added 'nothing' --- the empty list of theorems;
  1464 
  1465 
  1466 *** HOL ***
  1467 
  1468 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1469 corresponding virtual machine and a specification of its bytecode
  1470 verifier and a lightweight bytecode verifier, including proofs of
  1471 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1472 Cornelia Pusch (see also the homepage of project Bali at
  1473 http://isabelle.in.tum.de/Bali/);
  1474 
  1475 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1476 Clemens Ballarin;
  1477 
  1478 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1479 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1480 Rasmussen;
  1481 
  1482 * HOL/Lattice: fundamental concepts of lattice theory and order
  1483 structures, including duals, properties of bounds versus algebraic
  1484 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1485 Theorem for complete lattices etc.; may also serve as a demonstration
  1486 for abstract algebraic reasoning using axiomatic type classes, and
  1487 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1488 
  1489 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1490 von Oheimb;
  1491 
  1492 * HOL/IMPP: extension of IMP with local variables and mutually
  1493 recursive procedures, by David von Oheimb;
  1494 
  1495 * HOL/Lambda: converted into new-style theory and document;
  1496 
  1497 * HOL/ex/Multiquote: example of multiple nested quotations and
  1498 anti-quotations -- basically a generalized version of de-Bruijn
  1499 representation; very useful in avoiding lifting of operations;
  1500 
  1501 * HOL/record: added general record equality rule to simpset; fixed
  1502 select-update simplification procedure to handle extended records as
  1503 well; admit "r" as field name;
  1504 
  1505 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1506 other numeric types and also as the identity of groups, rings, etc.;
  1507 
  1508 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1509 Types nat and int belong to this axclass;
  1510 
  1511 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1512    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1513    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1514   two terms #m*u and #n*u are replaced by #(m+n)*u
  1515     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1516   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1517     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1518 
  1519 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1520 powerful prover for predicate logic but knows nothing of clasets; see
  1521 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1522 
  1523 * HOL: new version of "case_tac" subsumes both boolean case split and
  1524 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1525 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1526 
  1527 * HOL: simplification no longer dives into case-expressions: only the
  1528 selector expression is simplified, but not the remaining arms; to
  1529 enable full simplification of case-expressions for datatype t, you may
  1530 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1531 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1532 
  1533 * HOL/recdef: the recursion equations generated by 'recdef' for
  1534 function 'f' are now called f.simps instead of f.rules; if all
  1535 termination conditions are proved automatically, these simplification
  1536 rules are added to the simpset, as in primrec; rules may be named
  1537 individually as well, resulting in a separate list of theorems for
  1538 each equation;
  1539 
  1540 * HOL/While is a new theory that provides a while-combinator. It
  1541 permits the definition of tail-recursive functions without the
  1542 provision of a termination measure. The latter is necessary once the
  1543 invariant proof rule for while is applied.
  1544 
  1545 * HOL: new (overloaded) notation for the set of elements below/above
  1546 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1547 
  1548 * HOL: theorems impI, allI, ballI bound as "strip";
  1549 
  1550 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1551 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1552 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1553 
  1554 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1555 
  1556 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1557 main HOL, but was unused);
  1558 
  1559 * HOL: fewer consts declared as global (e.g. have to refer to
  1560 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1561 
  1562 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1563 in case of overlap with user translations (e.g. judgements over
  1564 tuples); (note that the underlying logical represenation is still
  1565 bogus);
  1566 
  1567 
  1568 *** ZF ***
  1569 
  1570 * ZF: simplification automatically cancels common terms in arithmetic
  1571 expressions over nat and int;
  1572 
  1573 * ZF: new treatment of nat to minimize type-checking: all operators
  1574 coerce their operands to a natural number using the function natify,
  1575 making the algebraic laws unconditional;
  1576 
  1577 * ZF: as above, for int: operators coerce their operands to an integer
  1578 using the function intify;
  1579 
  1580 * ZF: the integer library now contains many of the usual laws for the
  1581 orderings, including $<=, and monotonicity laws for $+ and $*;
  1582 
  1583 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1584 simplification;
  1585 
  1586 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1587 to the simplifier and classical reasoner simultaneously;
  1588 
  1589 
  1590 *** General ***
  1591 
  1592 * Provers: blast_tac now handles actual object-logic rules as
  1593 assumptions; note that auto_tac uses blast_tac internally as well;
  1594 
  1595 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1596 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1597 
  1598 * Provers: delrules now handles destruct rules as well (no longer need
  1599 explicit make_elim);
  1600 
  1601 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1602   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1603 use instead the strong form,
  1604   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1605 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1606 from destruct-rules;
  1607 
  1608 * Provers: Simplifier.easy_setup provides a fast path to basic
  1609 Simplifier setup for new object-logics;
  1610 
  1611 * Pure: AST translation rules no longer require constant head on LHS;
  1612 
  1613 * Pure: improved name spaces: ambiguous output is qualified; support
  1614 for hiding of names;
  1615 
  1616 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1617 XSYMBOL_HOME; no longer need to do manual configuration in most
  1618 situations;
  1619 
  1620 * system: compression of ML heaps images may now be controlled via -c
  1621 option of isabelle and isatool usedir (currently only observed by
  1622 Poly/ML);
  1623 
  1624 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1625 useful for remote X11);
  1626 
  1627 * system: provide TAGS file for Isabelle sources;
  1628 
  1629 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1630 order;
  1631 
  1632 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1633 timing flag supersedes proof_timing and Toplevel.trace;
  1634 
  1635 * ML: new combinators |>> and |>>> for incremental transformations
  1636 with secondary results (e.g. certain theory extensions):
  1637 
  1638 * ML: PureThy.add_defs gets additional argument to indicate potential
  1639 overloading (usually false);
  1640 
  1641 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1642 results;
  1643 
  1644 
  1645 
  1646 New in Isabelle99 (October 1999)
  1647 --------------------------------
  1648 
  1649 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1650 
  1651 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1652 are no longer simplified.  (This allows the simplifier to unfold recursive
  1653 functional programs.)  To restore the old behaviour, declare
  1654 
  1655     Delcongs [if_weak_cong];
  1656 
  1657 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1658 complement;
  1659 
  1660 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1661 
  1662 * HOL/datatype: mutual_induct_tac no longer exists --
  1663   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1664 
  1665 * HOL/typedef: fixed type inference for representing set; type
  1666 arguments now have to occur explicitly on the rhs as type constraints;
  1667 
  1668 * ZF: The con_defs part of an inductive definition may no longer refer
  1669 to constants declared in the same theory;
  1670 
  1671 * HOL, ZF: the function mk_cases, generated by the inductive
  1672 definition package, has lost an argument.  To simplify its result, it
  1673 uses the default simpset instead of a supplied list of theorems.
  1674 
  1675 * HOL/List: the constructors of type list are now Nil and Cons;
  1676 
  1677 * Simplifier: the type of the infix ML functions
  1678         setSSolver addSSolver setSolver addSolver
  1679 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1680 for packaging solvers. A solver is created via
  1681         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1682 where the string argument is only a comment.
  1683 
  1684 
  1685 *** Proof tools ***
  1686 
  1687 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1688 decision procedure for linear arithmetic. Currently it is used for
  1689 types `nat', `int', and `real' in HOL (see below); it can, should and
  1690 will be instantiated for other types and logics as well.
  1691 
  1692 * The simplifier now accepts rewrite rules with flexible heads, eg
  1693      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1694   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1695   matching.
  1696 
  1697 
  1698 *** General ***
  1699 
  1700 * New Isabelle/Isar subsystem provides an alternative to traditional
  1701 tactical theorem proving; together with the ProofGeneral/isar user
  1702 interface it offers an interactive environment for developing human
  1703 readable proof documents (Isar == Intelligible semi-automated
  1704 reasoning); for further information see isatool doc isar-ref,
  1705 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1706 
  1707 * improved and simplified presentation of theories: better HTML markup
  1708 (including colors), graph views in several sizes; isatool usedir now
  1709 provides a proper interface for user theories (via -P option); actual
  1710 document preparation based on (PDF)LaTeX is available as well (for
  1711 new-style theories only); see isatool doc system for more information;
  1712 
  1713 * native support for Proof General, both for classic Isabelle and
  1714 Isabelle/Isar;
  1715 
  1716 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1717 using the graph browser tool;
  1718 
  1719 * Isabelle manuals now also available as PDF;
  1720 
  1721 * theory loader rewritten from scratch (may not be fully
  1722 bug-compatible); old loadpath variable has been replaced by show_path,
  1723 add_path, del_path, reset_path functions; new operations such as
  1724 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1725 isatool doc ref);
  1726 
  1727 * improved isatool install: option -k creates KDE application icon,
  1728 option -p DIR installs standalone binaries;
  1729 
  1730 * added ML_PLATFORM setting (useful for cross-platform installations);
  1731 more robust handling of platform specific ML images for SML/NJ;
  1732 
  1733 * the settings environment is now statically scoped, i.e. it is never
  1734 created again in sub-processes invoked from isabelle, isatool, or
  1735 Isabelle;
  1736 
  1737 * path element specification '~~' refers to '$ISABELLE_HOME';
  1738 
  1739 * in locales, the "assumes" and "defines" parts may be omitted if
  1740 empty;
  1741 
  1742 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1743 long arrows);
  1744 
  1745 * new print_mode "HTML";
  1746 
  1747 * new flag show_tags controls display of tags of theorems (which are
  1748 basically just comments that may be attached by some tools);
  1749 
  1750 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1751 mode and goal output format:
  1752 
  1753 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1754 244c244
  1755 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1756 ---
  1757 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1758 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1759 181c181
  1760 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1761 ---
  1762 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1763 
  1764 * function bind_thms stores lists of theorems (cf. bind_thm);
  1765 
  1766 * new shorthand tactics ftac, eatac, datac, fatac;
  1767 
  1768 * qed (and friends) now accept "" as result name; in that case the
  1769 theorem is not stored, but proper checks and presentation of the
  1770 result still apply;
  1771 
  1772 * theorem database now also indexes constants "Trueprop", "all",
  1773 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1774 
  1775 
  1776 *** HOL ***
  1777 
  1778 ** HOL arithmetic **
  1779 
  1780 * There are now decision procedures for linear arithmetic over nat and
  1781 int:
  1782 
  1783 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1784 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1785 are treated as atomic; subformulae not involving type `nat' or `int'
  1786 are ignored; quantified subformulae are ignored unless they are
  1787 positive universal or negative existential. The tactic has to be
  1788 invoked by hand and can be a little bit slow. In particular, the
  1789 running time is exponential in the number of occurrences of `min' and
  1790 `max', and `-' on `nat'.
  1791 
  1792 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1793 (negated) (in)equalities among the premises and the conclusion into
  1794 account (i.e. no compound formulae) and does not know about `min' and
  1795 `max', and `-' on `nat'. It is fast and is used automatically by the
  1796 simplifier.
  1797 
  1798 NB: At the moment, these decision procedures do not cope with mixed
  1799 nat/int formulae where the two parts interact, such as `m < n ==>
  1800 int(m) < int(n)'.
  1801 
  1802 * HOL/Numeral provides a generic theory of numerals (encoded
  1803 efficiently as bit strings); setup for types nat/int/real is in place;
  1804 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1805 int, existing theories and proof scripts may require a few additional
  1806 type constraints;
  1807 
  1808 * integer division and remainder can now be performed on constant
  1809 arguments;
  1810 
  1811 * many properties of integer multiplication, division and remainder
  1812 are now available;
  1813 
  1814 * An interface to the Stanford Validity Checker (SVC) is available through the
  1815 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1816 are proved automatically.  SVC must be installed separately, and its results
  1817 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1818 invocation of the underlying oracle).  For SVC see
  1819   http://verify.stanford.edu/SVC
  1820 
  1821 * IsaMakefile: the HOL-Real target now builds an actual image;
  1822 
  1823 
  1824 ** HOL misc **
  1825 
  1826 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1827 (in Isabelle/Isar) -- by Gertrud Bauer;
  1828 
  1829 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1830 analysis for assembly languages with subtypes;
  1831 
  1832 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1833 -- avoids syntactic ambiguities and treats state, transition, and
  1834 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1835 changed syntax and (many) tactics;
  1836 
  1837 * HOL/inductive: Now also handles more general introduction rules such
  1838   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1839   theorems are now maintained within the theory (maintained via the
  1840   "mono" attribute);
  1841 
  1842 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1843   (using function types) such as
  1844 
  1845   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1846 
  1847 * HOL/record: record_simproc (part of the default simpset) takes care
  1848 of selectors applied to updated records; record_split_tac is no longer
  1849 part of the default claset; update_defs may now be removed from the
  1850 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1851 
  1852   claset_ref () := claset() addSWrapper record_split_wrapper;
  1853   Delsimprocs [record_simproc]
  1854 
  1855 * HOL/typedef: fixed type inference for representing set; type
  1856 arguments now have to occur explicitly on the rhs as type constraints;
  1857 
  1858 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1859 names rather than an ML expression;
  1860 
  1861 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1862 supplied later.  Program schemes can be defined, such as
  1863     "While B C s = (if B s then While B C (C s) else s)"
  1864 where the well-founded relation can be chosen after B and C have been given.
  1865 
  1866 * HOL/List: the constructors of type list are now Nil and Cons;
  1867 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1868 course, ML tools referring to List.list.op # etc. have to be adapted;
  1869 
  1870 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1871 disabled by default; run isabelle with option -m HOL to get back to
  1872 the original Gordon/HOL-style output;
  1873 
  1874 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1875 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1876 
  1877 * HOL basic syntax simplified (more orthogonal): all variants of
  1878 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1879 Eps operator is provided as well: "SOME x. P[x]";
  1880 
  1881 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1882 
  1883 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1884 thus available for user theories;
  1885 
  1886 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1887 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1888 time;
  1889 
  1890 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1891 several times and then mp;
  1892 
  1893 
  1894 *** LK ***
  1895 
  1896 * the notation <<...>> is now available as a notation for sequences of
  1897 formulas;
  1898 
  1899 * the simplifier is now installed
  1900 
  1901 * the axiom system has been generalized (thanks to Soren Heilmann)
  1902 
  1903 * the classical reasoner now has a default rule database
  1904 
  1905 
  1906 *** ZF ***
  1907 
  1908 * new primrec section allows primitive recursive functions to be given
  1909 directly (as in HOL) over datatypes and the natural numbers;
  1910 
  1911 * new tactics induct_tac and exhaust_tac for induction (or case
  1912 analysis) over datatypes and the natural numbers;
  1913 
  1914 * the datatype declaration of type T now defines the recursor T_rec;
  1915 
  1916 * simplification automatically does freeness reasoning for datatype
  1917 constructors;
  1918 
  1919 * automatic type-inference, with AddTCs command to insert new
  1920 type-checking rules;
  1921 
  1922 * datatype introduction rules are now added as Safe Introduction rules
  1923 to the claset;
  1924 
  1925 * the syntax "if P then x else y" is now available in addition to
  1926 if(P,x,y);
  1927 
  1928 
  1929 *** Internal programming interfaces ***
  1930 
  1931 * tuned simplifier trace output; new flag debug_simp;
  1932 
  1933 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1934 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1935 
  1936 * AxClass.axclass_tac lost the theory argument;
  1937 
  1938 * tuned current_goals_markers semantics: begin / end goal avoids
  1939 printing empty lines;
  1940 
  1941 * removed prs and prs_fn hook, which was broken because it did not
  1942 include \n in its semantics, forcing writeln to add one
  1943 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1944 string -> unit if you really want to output text without newline;
  1945 
  1946 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1947 plain output, interface builders may have to enable 'isabelle_font'
  1948 mode to get Isabelle font glyphs as before;
  1949 
  1950 * refined token_translation interface; INCOMPATIBILITY: output length
  1951 now of type real instead of int;
  1952 
  1953 * theory loader actions may be traced via new ThyInfo.add_hook
  1954 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1955 your own database of information attached to *whole* theories -- as
  1956 opposed to intra-theory data slots offered via TheoryDataFun;
  1957 
  1958 * proper handling of dangling sort hypotheses (at last!);
  1959 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1960 extra sort hypotheses that can be witnessed from the type signature;
  1961 the force_strip_shyps flag is gone, any remaining shyps are simply
  1962 left in the theorem (with a warning issued by strip_shyps_warning);
  1963 
  1964 
  1965 
  1966 New in Isabelle98-1 (October 1998)
  1967 ----------------------------------
  1968 
  1969 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1970 
  1971 * several changes of automated proof tools;
  1972 
  1973 * HOL: major changes to the inductive and datatype packages, including
  1974 some minor incompatibilities of theory syntax;
  1975 
  1976 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1977 called `inj_on';
  1978 
  1979 * HOL: removed duplicate thms in Arith:
  1980   less_imp_add_less  should be replaced by  trans_less_add1
  1981   le_imp_add_le      should be replaced by  trans_le_add1
  1982 
  1983 * HOL: unary minus is now overloaded (new type constraints may be
  1984 required);
  1985 
  1986 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1987 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1988 now taken as an integer constant.
  1989 
  1990 * Pure: ML function 'theory_of' renamed to 'theory';
  1991 
  1992 
  1993 *** Proof tools ***
  1994 
  1995 * Simplifier:
  1996   1. Asm_full_simp_tac is now more aggressive.
  1997      1. It will sometimes reorient premises if that increases their power to
  1998         simplify.
  1999      2. It does no longer proceed strictly from left to right but may also
  2000         rotate premises to achieve further simplification.
  2001      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2002      old Asm_full_simp_tac in that it does not rotate premises.
  2003   2. The simplifier now knows a little bit about nat-arithmetic.
  2004 
  2005 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2006 allows for selected deletion of wrappers, by introduction of names for
  2007 wrapper functionals.  This implies that addbefore, addSbefore,
  2008 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2009 and that adding two tactics with the same name overwrites the first
  2010 one (emitting a warning).
  2011   type wrapper = (int -> tactic) -> (int -> tactic)
  2012   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2013   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2014   delWrapper, delSWrapper: claset *  string            -> claset
  2015   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2016 
  2017 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2018 semantics; addbefore now affects only the unsafe part of step_tac
  2019 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2020 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2021 by Force_tac;
  2022 
  2023 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2024 compWrapper; added safe wrapper (and access functions for it);
  2025 
  2026 * HOL/split_all_tac is now much faster and fails if there is nothing
  2027 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2028 and the names of the automatically generated variables have changed.
  2029 split_all_tac has moved within claset() from unsafe wrappers to safe
  2030 wrappers, which means that !!-bound variables are split much more
  2031 aggressively, and safe_tac and clarify_tac now split such variables.
  2032 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2033 Note: the same holds for record_split_tac, which does the job of
  2034 split_all_tac for record fields.
  2035 
  2036 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2037 permanently to the default simpset using Addsplits just like
  2038 Addsimps. They can be removed via Delsplits just like
  2039 Delsimps. Lower-case versions are also available.
  2040 
  2041 * HOL/Simplifier: The rule split_if is now part of the default
  2042 simpset. This means that the simplifier will eliminate all occurrences
  2043 of if-then-else in the conclusion of a goal. To prevent this, you can
  2044 either remove split_if completely from the default simpset by
  2045 `Delsplits [split_if]' or remove it in a specific call of the
  2046 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2047 other case splitting rules to/from the default simpset: every datatype
  2048 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2049 t is the name of the datatype).
  2050 
  2051 * Classical reasoner / Simplifier combination: new force_tac (and
  2052 derivatives Force_tac, force) combines rewriting and classical
  2053 reasoning (and whatever other tools) similarly to auto_tac, but is
  2054 aimed to solve the given subgoal completely.
  2055 
  2056 
  2057 *** General ***
  2058 
  2059 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2060 and `goalw': the theory is no longer needed as an explicit argument -
  2061 the current theory context is used; assumptions are no longer returned
  2062 at the ML-level unless one of them starts with ==> or !!; it is
  2063 recommended to convert to these new commands using isatool fixgoal
  2064 (backup your sources first!);
  2065 
  2066 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2067 the current theory context, and 'theory' to lookup stored theories;
  2068 
  2069 * new theory section 'locale' for declaring constants, assumptions and
  2070 definitions that have local scope;
  2071 
  2072 * new theory section 'nonterminals' for purely syntactic types;
  2073 
  2074 * new theory section 'setup' for generic ML setup functions
  2075 (e.g. package initialization);
  2076 
  2077 * the distribution now includes Isabelle icons: see
  2078 lib/logo/isabelle-{small,tiny}.xpm;
  2079 
  2080 * isatool install - install binaries with absolute references to
  2081 ISABELLE_HOME/bin;
  2082 
  2083 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2084 
  2085 * print mode 'emacs' reserved for Isamode;
  2086 
  2087 * support multiple print (ast) translations per constant name;
  2088 
  2089 * theorems involving oracles are now printed with a suffixed [!];
  2090 
  2091 
  2092 *** HOL ***
  2093 
  2094 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2095 
  2096 * HOL/inductive package reorganized and improved: now supports mutual
  2097 definitions such as
  2098 
  2099   inductive EVEN ODD
  2100     intrs
  2101       null "0 : EVEN"
  2102       oddI "n : EVEN ==> Suc n : ODD"
  2103       evenI "n : ODD ==> Suc n : EVEN"
  2104 
  2105 new theorem list "elims" contains an elimination rule for each of the
  2106 recursive sets; inductive definitions now handle disjunctive premises
  2107 correctly (also ZF);
  2108 
  2109 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2110 "mutual_induct" no longer exists - the induction rule is always
  2111 contained in "induct";
  2112 
  2113 
  2114 * HOL/datatype package re-implemented and greatly improved: now
  2115 supports mutually recursive datatypes such as
  2116 
  2117   datatype
  2118     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2119             | SUM ('a aexp) ('a aexp)
  2120             | DIFF ('a aexp) ('a aexp)
  2121             | NUM 'a
  2122   and
  2123     'a bexp = LESS ('a aexp) ('a aexp)
  2124             | AND ('a bexp) ('a bexp)
  2125             | OR ('a bexp) ('a bexp)
  2126 
  2127 as well as indirectly recursive datatypes such as
  2128 
  2129   datatype
  2130     ('a, 'b) term = Var 'a
  2131                   | App 'b ((('a, 'b) term) list)
  2132 
  2133 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2134 induction on mutually / indirectly recursive datatypes.
  2135 
  2136 Primrec equations are now stored in theory and can be accessed via
  2137 <function_name>.simps.
  2138 
  2139 INCOMPATIBILITIES:
  2140 
  2141   - Theories using datatypes must now have theory Datatype as an
  2142     ancestor.
  2143   - The specific <typename>.induct_tac no longer exists - use the
  2144     generic induct_tac instead.
  2145   - natE has been renamed to nat.exhaust - use exhaust_tac
  2146     instead of res_inst_tac ... natE. Note that the variable
  2147     names in nat.exhaust differ from the names in natE, this
  2148     may cause some "fragile" proofs to fail.
  2149   - The theorems split_<typename>_case and split_<typename>_case_asm
  2150     have been renamed to <typename>.split and <typename>.split_asm.
  2151   - Since default sorts of type variables are now handled correctly,
  2152     some datatype definitions may have to be annotated with explicit
  2153     sort constraints.
  2154   - Primrec definitions no longer require function name and type
  2155     of recursive argument.
  2156 
  2157 Consider using isatool fixdatatype to adapt your theories and proof
  2158 scripts to the new package (backup your sources first!).
  2159 
  2160 
  2161 * HOL/record package: considerably improved implementation; now
  2162 includes concrete syntax for record types, terms, updates; theorems
  2163 for surjective pairing and splitting !!-bound record variables; proof
  2164 support is as follows:
  2165 
  2166   1) standard conversions (selectors or updates applied to record
  2167 constructor terms) are part of the standard simpset;
  2168 
  2169   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2170 made part of standard simpset and claset via addIffs;
  2171 
  2172   3) a tactic for record field splitting (record_split_tac) is part of
  2173 the standard claset (addSWrapper);
  2174 
  2175 To get a better idea about these rules you may retrieve them via
  2176 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2177 the name of your record type.
  2178 
  2179 The split tactic 3) conceptually simplifies by the following rule:
  2180 
  2181   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2182 
  2183 Thus any record variable that is bound by meta-all will automatically
  2184 blow up into some record constructor term, consequently the
  2185 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2186 solve record problems automatically.
  2187 
  2188 
  2189 * reorganized the main HOL image: HOL/Integ and String loaded by
  2190 default; theory Main includes everything;
  2191 
  2192 * automatic simplification of integer sums and comparisons, using cancellation;
  2193 
  2194 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2195 
  2196 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2197 
  2198 * many new identities for unions, intersections, set difference, etc.;
  2199 
  2200 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2201 called split_if, split_split, split_sum_case and split_nat_case (to go
  2202 with add/delsplits);
  2203 
  2204 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2205 (?x::unit) = (); this is made part of the default simpset, which COULD
  2206 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2207 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2208 unit_abs_eta_conv is added in order to counter the effect of
  2209 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2210 %u.f();
  2211 
  2212 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2213 makes more sense);
  2214 
  2215 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2216   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2217   disjointness reasoning but breaking a few old proofs.
  2218 
  2219 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2220 to 'converse' from 'inverse' (for compatibility with ZF and some
  2221 literature);
  2222 
  2223 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2224 the well-founded relation;
  2225 
  2226 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2227     Compl A.  The "Compl" syntax remains available as input syntax for this
  2228     release ONLY.
  2229 
  2230 * HOL/Update: new theory of function updates:
  2231     f(a:=b) == %x. if x=a then b else f x
  2232 may also be iterated as in f(a:=b,c:=d,...);
  2233 
  2234 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2235 
  2236 * HOL/List:
  2237   - new function list_update written xs[i:=v] that updates the i-th
  2238     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2239   - new function `upt' written [i..j(] which generates the list
  2240     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2241     bound write [i..j], which is a shorthand for [i..j+1(].
  2242   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2243 
  2244 * HOL/Arith:
  2245   - removed 'pred' (predecessor) function;
  2246   - generalized some theorems about n-1;
  2247   - many new laws about "div" and "mod";
  2248   - new laws about greatest common divisors (see theory ex/Primes);
  2249 
  2250 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2251 instead of "inverse";
  2252 
  2253 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2254   of the multiset ordering;
  2255 
  2256 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2257   (not included by default);
  2258 
  2259 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2260 
  2261 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2262   programs, i.e. different program variables may have different types.
  2263 
  2264 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2265   [previously, this check worked only if the rewrite rule was unconditional]
  2266   Now rew can involve either definitions or equalities (either == or =).
  2267 
  2268 
  2269 *** ZF ***
  2270 
  2271 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2272   only the theorems proved on ZF.ML;
  2273 
  2274 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2275   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2276   disjointness reasoning but breaking a few old proofs.
  2277 
  2278 * ZF/Update: new theory of function updates
  2279     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2280   may also be iterated as in f(a:=b,c:=d,...);
  2281 
  2282 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2283 
  2284 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2285   [previously, this check worked only if the rewrite rule was unconditional]
  2286   Now rew can involve either definitions or equalities (either == or =).
  2287 
  2288 * case_tac provided for compatibility with HOL
  2289     (like the old excluded_middle_tac, but with subgoals swapped)
  2290 
  2291 
  2292 *** Internal programming interfaces ***
  2293 
  2294 * Pure: several new basic modules made available for general use, see
  2295 also src/Pure/README;
  2296 
  2297 * improved the theory data mechanism to support encapsulation (data
  2298 kind name replaced by private Object.kind, acting as authorization
  2299 key); new type-safe user interface via functor TheoryDataFun; generic
  2300 print_data function becomes basically useless;
  2301 
  2302 * removed global_names compatibility flag -- all theory declarations
  2303 are qualified by default;
  2304 
  2305 * module Pure/Syntax now offers quote / antiquote translation
  2306 functions (useful for Hoare logic etc. with implicit dependencies);
  2307 see HOL/ex/Antiquote for an example use;
  2308 
  2309 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2310 cterm -> thm;
  2311 
  2312 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2313 subgoal;
  2314 
  2315 * Display.print_goals function moved to Locale.print_goals;
  2316 
  2317 * standard print function for goals supports current_goals_markers
  2318 variable for marking begin of proof, end of proof, start of goal; the
  2319 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2320 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2321 for example;
  2322 
  2323 
  2324 
  2325 New in Isabelle98 (January 1998)
  2326 --------------------------------
  2327 
  2328 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2329 
  2330 * changed lexical syntax of terms / types: dots made part of long
  2331 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2332 
  2333 * simpset (and claset) reference variable replaced by functions
  2334 simpset / simpset_ref;
  2335 
  2336 * no longer supports theory aliases (via merge) and non-trivial
  2337 implicit merge of thms' signatures;
  2338 
  2339 * most internal names of constants changed due to qualified names;
  2340 
  2341 * changed Pure/Sequence interface (see Pure/seq.ML);
  2342 
  2343 
  2344 *** General Changes ***
  2345 
  2346 * hierachically structured name spaces (for consts, types, axms, thms
  2347 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2348 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2349 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2350 long_names for fully qualified output names; NOTE: ML programs
  2351 (special tactics, packages etc.) referring to internal names may have
  2352 to be adapted to cope with fully qualified names; in case of severe
  2353 backward campatibility problems try setting 'global_names' at compile
  2354 time to have enrything declared within a flat name space; one may also
  2355 fine tune name declarations in theories via the 'global' and 'local'
  2356 section;
  2357 
  2358 * reimplemented the implicit simpset and claset using the new anytype
  2359 data filed in signatures; references simpset:simpset ref etc. are
  2360 replaced by functions simpset:unit->simpset and
  2361 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2362 to patch your ML files accordingly;
  2363 
  2364 * HTML output now includes theory graph data for display with Java
  2365 applet or isatool browser; data generated automatically via isatool
  2366 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2367 
  2368 * defs may now be conditional; improved rewrite_goals_tac to handle
  2369 conditional equations;
  2370 
  2371 * defs now admits additional type arguments, using TYPE('a) syntax;
  2372 
  2373 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2374 creates a new theory node; implicit merge of thms' signatures is
  2375 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2376 transfer:theory->thm->thm in (rare) cases;
  2377 
  2378 * improved handling of draft signatures / theories; draft thms (and
  2379 ctyps, cterms) are automatically promoted to real ones;
  2380 
  2381 * slightly changed interfaces for oracles: admit many per theory, named
  2382 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2383 
  2384 * print_goals: optional output of const types (set show_consts and
  2385 show_types);
  2386 
  2387 * improved output of warnings (###) and errors (***);
  2388 
  2389 * subgoal_tac displays a warning if the new subgoal has type variables;
  2390 
  2391 * removed old README and Makefiles;
  2392 
  2393 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2394 
  2395 * removed obsolete init_pps and init_database;
  2396 
  2397 * deleted the obsolete tactical STATE, which was declared by
  2398     fun STATE tacfun st = tacfun st st;
  2399 
  2400 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2401 (which abbreviates $HOME);
  2402 
  2403 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2404 use isatool fixseq to adapt your ML programs (this works for fully
  2405 qualified references to the Sequence structure only!);
  2406 
  2407 * use_thy no longer requires writable current directory; it always
  2408 reloads .ML *and* .thy file, if either one is out of date;
  2409 
  2410 
  2411 *** Classical Reasoner ***
  2412 
  2413 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2414 tactics that use classical reasoning to simplify a subgoal without
  2415 splitting it into several subgoals;
  2416 
  2417 * Safe_tac: like safe_tac but uses the default claset;
  2418 
  2419 
  2420 *** Simplifier ***
  2421 
  2422 * added simplification meta rules:
  2423     (asm_)(full_)simplify: simpset -> thm -> thm;
  2424 
  2425 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2426 logics (again);
  2427 
  2428 * added prems argument to simplification procedures;
  2429 
  2430 * HOL, FOL, ZF: added infix function `addsplits':
  2431   instead of `<simpset> setloop (split_tac <thms>)'
  2432   you can simply write `<simpset> addsplits <thms>'
  2433 
  2434 
  2435 *** Syntax ***
  2436 
  2437 * TYPE('a) syntax for type reflection terms;
  2438 
  2439 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2440 
  2441 * pretty printer: changed order of mixfix annotation preference (again!);
  2442 
  2443 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2444 
  2445 
  2446 *** HOL ***
  2447 
  2448 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2449   with `addloop' of the simplifier to faciliate case splitting in premises.
  2450 
  2451 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2452 
  2453 * HOL/Auth: new protocol proofs including some for the Internet
  2454   protocol TLS;
  2455 
  2456 * HOL/Map: new theory of `maps' a la VDM;
  2457 
  2458 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2459 cancelling out common nat summands from =, <, <= (in)equalities, or
  2460 differences; simplification procedures nat_cancel_factor for
  2461 cancelling common factor from =, <, <= (in)equalities over natural
  2462 sums; nat_cancel contains both kinds of procedures, it is installed by
  2463 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2464 
  2465 * HOL/simplifier: terms of the form
  2466   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2467   are rewritten to
  2468   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2469   and those of the form
  2470   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2471   are rewritten to
  2472   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2473 
  2474 * HOL/datatype
  2475   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2476 
  2477   P(t_case f1 ... fn x) =
  2478      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2479         ...
  2480        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2481      )
  2482 
  2483   and a theorem `split_t_case_asm' of the form
  2484 
  2485   P(t_case f1 ... fn x) =
  2486     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2487         ...
  2488        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2489      )
  2490   which can be added to a simpset via `addsplits'. The existing theorems
  2491   expand_list_case and expand_option_case have been renamed to
  2492   split_list_case and split_option_case.
  2493 
  2494 * HOL/Arithmetic:
  2495   - `pred n' is automatically converted to `n-1'.
  2496     Users are strongly encouraged not to use `pred' any longer,
  2497     because it will disappear altogether at some point.
  2498   - Users are strongly encouraged to write "0 < n" rather than
  2499     "n ~= 0". Theorems and proof tools have been modified towards this
  2500     `standard'.
  2501 
  2502 * HOL/Lists:
  2503   the function "set_of_list" has been renamed "set" (and its theorems too);
  2504   the function "nth" now takes its arguments in the reverse order and
  2505   has acquired the infix notation "!" as in "xs!n".
  2506 
  2507 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2508 
  2509 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2510   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2511 
  2512 * HOL/record: extensible records with schematic structural subtyping
  2513 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2514 still lacks various theorems and concrete record syntax;
  2515 
  2516 
  2517 *** HOLCF ***
  2518 
  2519 * removed "axioms" and "generated by" sections;
  2520 
  2521 * replaced "ops" section by extended "consts" section, which is capable of
  2522   handling the continuous function space "->" directly;
  2523 
  2524 * domain package:
  2525   . proves theorems immediately and stores them in the theory,
  2526   . creates hierachical name space,
  2527   . now uses normal mixfix annotations (instead of cinfix...),
  2528   . minor changes to some names and values (for consistency),
  2529   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2530   . separator between mutual domain defs: changed "," to "and",
  2531   . improved handling of sort constraints;  now they have to
  2532     appear on the left-hand side of the equations only;
  2533 
  2534 * fixed LAM <x,y,zs>.b syntax;
  2535 
  2536 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2537 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2538 
  2539 
  2540 *** FOL and ZF ***
  2541 
  2542 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2543   with `addloop' of the simplifier to faciliate case splitting in premises.
  2544 
  2545 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2546 in HOL, they strip ALL and --> from proved theorems;
  2547 
  2548 
  2549 
  2550 New in Isabelle94-8 (May 1997)
  2551 ------------------------------
  2552 
  2553 *** General Changes ***
  2554 
  2555 * new utilities to build / run / maintain Isabelle etc. (in parts
  2556 still somewhat experimental); old Makefiles etc. still functional;
  2557 
  2558 * new 'Isabelle System Manual';
  2559 
  2560 * INSTALL text, together with ./configure and ./build scripts;
  2561 
  2562 * reimplemented type inference for greater efficiency, better error
  2563 messages and clean internal interface;
  2564 
  2565 * prlim command for dealing with lots of subgoals (an easier way of
  2566 setting goals_limit);
  2567 
  2568 
  2569 *** Syntax ***
  2570 
  2571 * supports alternative (named) syntax tables (parser and pretty
  2572 printer); internal interface is provided by add_modesyntax(_i);
  2573 
  2574 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2575 be used in conjunction with the Isabelle symbol font; uses the
  2576 "symbols" syntax table;
  2577 
  2578 * added token_translation interface (may translate name tokens in
  2579 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2580 the current print_mode); IMPORTANT: user print translation functions
  2581 are responsible for marking newly introduced bounds
  2582 (Syntax.mark_boundT);
  2583 
  2584 * token translations for modes "xterm" and "xterm_color" that display
  2585 names in bold, underline etc. or colors (which requires a color
  2586 version of xterm);
  2587 
  2588 * infixes may now be declared with names independent of their syntax;
  2589 
  2590 * added typed_print_translation (like print_translation, but may
  2591 access type of constant);
  2592 
  2593 
  2594 *** Classical Reasoner ***
  2595 
  2596 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2597 some limitations.  Blast_tac...
  2598   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2599   + ignores elimination rules that don't have the correct format
  2600         (the conclusion MUST be a formula variable)
  2601   + ignores types, which can make HOL proofs fail
  2602   + rules must not require higher-order unification, e.g. apply_type in ZF
  2603     [message "Function Var's argument not a bound variable" relates to this]
  2604   + its proof strategy is more general but can actually be slower
  2605 
  2606 * substitution with equality assumptions no longer permutes other
  2607 assumptions;
  2608 
  2609 * minor changes in semantics of addafter (now called addaltern); renamed
  2610 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2611 (and access functions for it);
  2612 
  2613 * improved combination of classical reasoner and simplifier:
  2614   + functions for handling clasimpsets
  2615   + improvement of addss: now the simplifier is called _after_ the
  2616     safe steps.
  2617   + safe variant of addss called addSss: uses safe simplifications
  2618     _during_ the safe steps. It is more complete as it allows multiple
  2619     instantiations of unknowns (e.g. with slow_tac).
  2620 
  2621 *** Simplifier ***
  2622 
  2623 * added interface for simplification procedures (functions that
  2624 produce *proven* rewrite rules on the fly, depending on current
  2625 redex);
  2626 
  2627 * ordering on terms as parameter (used for ordered rewriting);
  2628 
  2629 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2630 
  2631 * the solver is now split into a safe and an unsafe part.
  2632 This should be invisible for the normal user, except that the
  2633 functions setsolver and addsolver have been renamed to setSolver and
  2634 addSolver; added safe_asm_full_simp_tac;
  2635 
  2636 
  2637 *** HOL ***
  2638 
  2639 * a generic induction tactic `induct_tac' which works for all datatypes and
  2640 also for type `nat';
  2641 
  2642 * a generic case distinction tactic `exhaust_tac' which works for all
  2643 datatypes and also for type `nat';
  2644 
  2645 * each datatype comes with a function `size';
  2646 
  2647 * patterns in case expressions allow tuple patterns as arguments to
  2648 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2649 
  2650 * primrec now also works with type nat;
  2651 
  2652 * recdef: a new declaration form, allows general recursive functions to be
  2653 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2654 
  2655 * the constant for negation has been renamed from "not" to "Not" to
  2656 harmonize with FOL, ZF, LK, etc.;
  2657 
  2658 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2659 infinite lists;
  2660 
  2661 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2662 
  2663 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2664 problems in commutative rings, using axiomatic type classes for + and *;
  2665 
  2666 * more examples in HOL/MiniML and HOL/Auth;
  2667 
  2668 * more default rewrite rules for quantifiers, union/intersection;
  2669 
  2670 * a new constant `arbitrary == @x.False';
  2671 
  2672 * HOLCF/IOA replaces old HOL/IOA;
  2673 
  2674 * HOLCF changes: derived all rules and arities
  2675   + axiomatic type classes instead of classes
  2676   + typedef instead of faking type definitions
  2677   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2678   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2679   + eliminated the types void, one, tr
  2680   + use unit lift and bool lift (with translations) instead of one and tr
  2681   + eliminated blift from Lift3.thy (use Def instead of blift)
  2682   all eliminated rules are derived as theorems --> no visible changes ;
  2683 
  2684 
  2685 *** ZF ***
  2686 
  2687 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2688 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2689 as ZF_cs addSIs [equalityI];
  2690 
  2691 
  2692 
  2693 New in Isabelle94-7 (November 96)
  2694 ---------------------------------
  2695 
  2696 * allowing negative levels (as offsets) in prlev and choplev;
  2697 
  2698 * super-linear speedup for large simplifications;
  2699 
  2700 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2701 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2702 FAIL); can suppress it using the command Delsimps (ex_simps @
  2703 all_simps); De Morgan laws are also now included, by default;
  2704 
  2705 * improved printing of ==>  :  ~:
  2706 
  2707 * new object-logic "Sequents" adds linear logic, while replacing LK
  2708 and Modal (thanks to Sara Kalvala);
  2709 
  2710 * HOL/Auth: correctness proofs for authentication protocols;
  2711 
  2712 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2713 examples on HOL/Auth);
  2714 
  2715 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2716 the rewriter and classical reasoner simultaneously;
  2717 
  2718 * function uresult no longer returns theorems in "standard" format;
  2719 regain previous version by: val uresult = standard o uresult;
  2720 
  2721 
  2722 
  2723 New in Isabelle94-6
  2724 -------------------
  2725 
  2726 * oracles -- these establish an interface between Isabelle and trusted
  2727 external reasoners, which may deliver results as theorems;
  2728 
  2729 * proof objects (in particular record all uses of oracles);
  2730 
  2731 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2732 
  2733 * "constdefs" section in theory files;
  2734 
  2735 * "primrec" section (HOL) no longer requires names;
  2736 
  2737 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2738 
  2739 
  2740 
  2741 New in Isabelle94-5
  2742 -------------------
  2743 
  2744 * reduced space requirements;
  2745 
  2746 * automatic HTML generation from theories;
  2747 
  2748 * theory files no longer require "..." (quotes) around most types;
  2749 
  2750 * new examples, including two proofs of the Church-Rosser theorem;
  2751 
  2752 * non-curried (1994) version of HOL is no longer distributed;
  2753 
  2754 
  2755 
  2756 New in Isabelle94-4
  2757 -------------------
  2758 
  2759 * greatly reduced space requirements;
  2760 
  2761 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2762 
  2763 * searchable theorem database (see the section "Retrieving theorems" on
  2764 page 8 of the Reference Manual);
  2765 
  2766 * new examples, including Grabczewski's monumental case study of the
  2767 Axiom of Choice;
  2768 
  2769 * The previous version of HOL renamed to Old_HOL;
  2770 
  2771 * The new version of HOL (previously called CHOL) uses a curried syntax
  2772 for functions.  Application looks like f a b instead of f(a,b);
  2773 
  2774 * Mutually recursive inductive definitions finally work in HOL;
  2775 
  2776 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2777 translates to the operator "split";
  2778 
  2779 
  2780 
  2781 New in Isabelle94-3
  2782 -------------------
  2783 
  2784 * new infix operator, addss, allowing the classical reasoner to
  2785 perform simplification at each step of its search.  Example:
  2786         fast_tac (cs addss ss)
  2787 
  2788 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2789 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2790 look like (a,b) instead of <a,b>;
  2791 
  2792 * PLEASE NOTE: CHOL will eventually replace HOL!
  2793 
  2794 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2795 It translates to the operator "split".  A new theory of integers is available;
  2796 
  2797 * In ZF, integer numerals now denote two's-complement binary integers.
  2798 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2799 
  2800 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2801 of the Axiom of Choice;
  2802 
  2803 
  2804 
  2805 New in Isabelle94-2
  2806 -------------------
  2807 
  2808 * Significantly faster resolution;
  2809 
  2810 * the different sections in a .thy file can now be mixed and repeated
  2811 freely;
  2812 
  2813 * Database of theorems for FOL, HOL and ZF.  New
  2814 commands including qed, qed_goal and bind_thm store theorems in the database.
  2815 
  2816 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2817 a given theory (thms_of), or find out what theory a theorem was proved in
  2818 (theory_of_thm);
  2819 
  2820 * Bugs fixed in the inductive definition and datatype packages;
  2821 
  2822 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2823 and HOL_dup_cs obsolete;
  2824 
  2825 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2826 have been removed;
  2827 
  2828 * Simpler definition of function space in ZF;
  2829 
  2830 * new results about cardinal and ordinal arithmetic in ZF;
  2831 
  2832 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2833 types;
  2834 
  2835 
  2836 $Id$