NEWS
author paulson
Sat Jul 31 20:54:23 2004 +0200 (2004-07-31)
changeset 15094 a7d1a3fdc30d
parent 15089 430264838064
child 15103 79846e8792eb
permissions -rw-r--r--
conversion of Hyperreal/{Fact,Filter} to Isar scripts
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Provers/trancl.ML:  new transitivity reasoner for transitive and
    10   reflexive-transitive closure of relations.
    11 
    12 * Pure: considerably improved version of 'constdefs' command.  Now
    13   performs automatic type-inference of declared constants; additional
    14   support for local structure declarations (cf. locales and HOL
    15   records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    16   to observe strictly sequential dependencies of definitions within a
    17   single 'constdefs' section; moreover, the declared name needs to be
    18   an identifier.  If all fails, consider to fall back on 'consts' and
    19   'defs' separately.
    20 
    21 * Pure: improved indexed syntax and implicit structures.  First of
    22   all, indexed syntax provides a notational device for subscripted
    23   application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    24   expressions.  Secondly, in a local context with structure
    25   declarations, number indexes \<^sub>n or the empty index (default
    26   number 1) refer to a certain fixed variable implicitly; option
    27   show_structs controls printing of implicit structures.  Typical
    28   applications of these concepts involve record types and locales.
    29 
    30 * Pure: clear separation of logical types and nonterminals, where the
    31   latter may only occur in 'syntax' specifications or type
    32   abbreviations.  Before that distinction was only partially
    33   implemented via type class "logic" vs. "{}".  Potential
    34   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
    35   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
    36   specifications may require further adaption (e.g. Cube/Base.thy).
    37 
    38 * Pure: removed obsolete type class "logic", use the top sort {}
    39   instead.  Note that non-logical types should be declared as
    40   'nonterminals' rather than 'types'.  INCOMPATIBILITY for new
    41   object-logic specifications.
    42 
    43 * Pure: print_tac now outputs the goal through the trace channel.
    44 
    45 * Pure: reference Namespace.unique_names included.  If true the
    46   (shortest) namespace-prefix is printed to disambiguate conflicts (as
    47   yet). If false the first entry wins (as during parsing). Default
    48   value is true.
    49 
    50 * Pure: tuned internal renaming of symbolic identifiers -- attach
    51   primes instead of base 26 numbers.
    52 
    53 * Pure/Syntax: inner syntax includes (*(*nested*) comments*).
    54 
    55 * Pure/Syntax: pretty pinter now supports unbreakable blocks,
    56   specified in mixfix annotations as "(00...)".
    57 
    58 * Pure/Syntax: 'advanced' translation functions (parse_translation
    59   etc.) may depend on the signature of the theory context being
    60   presently used for parsing/printing, see also isar-ref manual.
    61 
    62 * Pure/Simplifier: simplification procedures may now take the current
    63   simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
    64   interface), which is very useful for calling the Simplifier
    65   recursively.  Minor INCOMPATIBILITY: the 'prems' argument of
    66   simprocs is gone -- use prems_of_ss on the simpset instead.
    67   Moreover, the low-level mk_simproc no longer applies Logic.varify
    68   internally, to allow for use in a context of fixed variables.
    69 
    70 * Provers: Simplifier and Classical Reasoner now support proof context
    71   dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
    72   components are stored in the theory and patched into the
    73   simpset/claset when used in an Isar proof context.  Context
    74   dependent components are maintained by the following theory
    75   operations:
    76 
    77     Simplifier.add_context_simprocs
    78     Simplifier.del_context_simprocs
    79     Simplifier.set_context_subgoaler
    80     Simplifier.reset_context_subgoaler
    81     Simplifier.add_context_looper
    82     Simplifier.del_context_looper
    83     Simplifier.add_context_unsafe_solver
    84     Simplifier.add_context_safe_solver
    85 
    86     Classical.add_context_safe_wrapper
    87     Classical.del_context_safe_wrapper
    88     Classical.add_context_unsafe_wrapper
    89     Classical.del_context_unsafe_wrapper
    90 
    91   IMPORTANT NOTE: proof tools (methods etc.) need to use
    92   local_simpset_of and local_claset_of to instead of the primitive
    93   Simplifier.get_local_simpset and Classical.get_local_claset,
    94   respectively, in order to see the context dependent fields!
    95 
    96 * Document preparation: antiquotations now provide the option
    97   'locale=NAME' to specify an alternative context used for evaluating
    98   and printing the subsequent argument, as in @{thm [locale=LC]
    99   fold_commute}, for example.
   100 
   101 * Document preparation: commands 'display_drafts' and 'print_drafts'
   102   perform simple output of raw sources.  Only those symbols that do
   103   not require additional LaTeX packages (depending on comments in
   104   isabellesym.sty) are displayed properly, everything else is left
   105   verbatim.  We use isatool display and isatool print as front ends;
   106   these are subject to the DVI_VIEWER and PRINT_COMMAND settings,
   107   respectively.
   108 
   109 * ML: output via the Isabelle channels of writeln/warning/error
   110   etc. is now passed through Output.output, with a hook for arbitrary
   111   transformations depending on the print_mode (cf. Output.add_mode --
   112   the first active mode that provides a output function wins).
   113   Already formatted output may be embedded into further text via
   114   Output.raw; the result of Pretty.string_of/str_of and derived
   115   functions (string_of_term/cterm/thm etc.) is already marked raw to
   116   accommodate easy composition of diagnostic messages etc.
   117   Programmers rarely need to care about Output.output or Output.raw at
   118   all, with some notable exceptions: Output.output is required when
   119   bypassing the standard channels (writeln etc.), or in token
   120   translations to produce properly formatted results; Output.raw is
   121   required when capturing already output material that will eventually
   122   be presented to the user a second time.  For the default print mode,
   123   both Output.output and Output.raw have no effect.
   124 
   125 
   126 *** HOL ***
   127 
   128 * HOL/record: reimplementation of records. Improved scalability for
   129   records with many fields, avoiding performance problems for type
   130   inference. Records are no longer composed of nested field types, but
   131   of nested extension types. Therefore the record type only grows
   132   linear in the number of extensions and not in the number of fields.
   133   The top-level (users) view on records is preserved.  Potential
   134   INCOMPATIBILITY only in strange cases, where the theory depends on
   135   the old record representation. The type generated for a record is
   136   called <record_name>_ext_type.
   137 
   138 * HOL/record: Reference record_quick_and_dirty_sensitive can be
   139   enabled to skip the proofs triggered by a record definition or a
   140   simproc (if quick_and_dirty is enabled). Definitions of large
   141   records can take quite long.
   142 
   143 * HOL/record: "record_upd_simproc" for simplification of multiple
   144   record updates enabled by default.  Moreover, trivial updates are
   145   also removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   146   occasionally, since simplification is more powerful by default.
   147 
   148 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
   149 
   150   syntax (epsilon)
   151     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   152 
   153   The symbol \<some> is displayed as the alternative epsilon of LaTeX
   154   and x-symbol; use option '-m epsilon' to get it actually printed.
   155   Moreover, the mathematically important symbolic identifier
   156   \<epsilon> becomes available as variable, constant etc.
   157 
   158 * HOL/SetInterval: The syntax for open intervals has changed:
   159 
   160   Old         New
   161   {..n(}   -> {..<n}
   162   {)n..}   -> {n<..}
   163   {m..n(}  -> {m..<n}
   164   {)m..n}  -> {m<..n}
   165   {)m..n(} -> {m<..<n}
   166 
   167   The old syntax is still supported but will disappear in the future.
   168   For conversion use the following emacs search and replace patterns:
   169 
   170   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   171   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   172 
   173   They are not perfect but work quite well.
   174 
   175 * HOL: The syntax for 'setsum', summation over finite sets, has changed:
   176 
   177   The syntax for 'setsum (%x. e) A' used to be '\<Sum>x:A. e'
   178   and is now either 'SUM x:A. e' or '\<Sum>x\<in>A. e'.
   179 
   180   There is new syntax for summation over finite sets:
   181 
   182   '\<Sum>x | P. e'    is the same as  'setsum (%x. e) {x. P}'
   183   '\<Sum>x=a..b. e'   is the same as  'setsum (%x. e) {a..b}'
   184   '\<Sum>x=a..<b. e'  is the same as  'setsum (%x. e) {a..<b}'
   185   '\<Sum>x<k. e'      is the same as  'setsum (%x. e) {..<k}'
   186 
   187   Function 'Summation' over nat is gone, its syntax '\<Sum>i<k. e'
   188   now translates into 'setsum' as above.
   189 
   190 * HOL/Simplifier: Is now set up to reason about transitivity chains
   191   involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
   192   provided by Provers/trancl.ML as additional solvers.
   193   INCOMPATIBILITY: old proofs break occasionally as simplification may
   194   now solve more goals than previously.
   195 
   196 
   197 *** HOLCF ***
   198 
   199 * HOLCF: discontinued special version of 'constdefs' (which used to
   200   support continuous functions) in favor of the general Pure one with
   201   full type-inference.
   202 
   203 
   204 *** ZF ***
   205 
   206 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the
   207   First Isomorphism Theorem (on quotienting by the kernel of a
   208   homomorphism).
   209 
   210 * ZF/Simplifier: install second copy of type solver that actually
   211   makes use of TC rules declared to Isar proof contexts (or locales);
   212   the old version is still required for ML proof scripts.
   213 
   214 
   215 
   216 New in Isabelle2004 (April 2004)
   217 --------------------------------
   218 
   219 *** General ***
   220 
   221 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   222   Replaces linorder.ML.
   223 
   224 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   225   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   226   (\<a>...\<z>), are now considered normal letters, and can therefore
   227   be used anywhere where an ASCII letter (a...zA...Z) has until
   228   now. COMPATIBILITY: This obviously changes the parsing of some
   229   terms, especially where a symbol has been used as a binder, say
   230   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   231   as an identifier.  Fix it by inserting a space around former
   232   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   233   existing theory and ML files.
   234 
   235 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   236 
   237 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   238   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   239   a normal (but invisible) letter. For multiple letter subscripts repeat
   240   \<^isub> like this: x\<^isub>1\<^isub>2.
   241 
   242 * Pure: There are now sub-/superscripts that can span more than one
   243   character. Text between \<^bsub> and \<^esub> is set in subscript in
   244   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   245   superscript. The new control characters are not identifier parts.
   246 
   247 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   248   content of "..." to the latex file instead of \isacntrl... . The "..."
   249   may consist of any printable characters excluding the end bracket >.
   250 
   251 * Pure: Using new Isar command "finalconsts" (or the ML functions
   252   Theory.add_finals or Theory.add_finals_i) it is now possible to
   253   declare constants "final", which prevents their being given a definition
   254   later.  It is useful for constants whose behaviour is fixed axiomatically
   255   rather than definitionally, such as the meta-logic connectives.
   256 
   257 * Pure: 'instance' now handles general arities with general sorts
   258   (i.e. intersections of classes),
   259 
   260 * Presentation: generated HTML now uses a CSS style sheet to make layout
   261   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   262   It can be changed to alter the colors/layout of generated pages.
   263 
   264 
   265 *** Isar ***
   266 
   267 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   268   cut_tac, subgoal_tac and thin_tac:
   269   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   270     locales are no longer forced to write Isar proof scripts.
   271     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   272     emulations.
   273   - INCOMPATIBILITY: names of variables to be instantiated may no
   274     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   275     This is consistent with the instantiation attribute "where".
   276 
   277 * Attributes "where" and "of":
   278   - Now take type variables of instantiated theorem into account when reading
   279     the instantiation string.  This fixes a bug that caused instantiated
   280     theorems to have too special types in some circumstances.
   281   - "where" permits explicit instantiations of type variables.
   282 
   283 * Calculation commands "moreover" and "also" no longer interfere with
   284   current facts ("this"), admitting arbitrary combinations with "then"
   285   and derived forms.
   286 
   287 * Locales:
   288   - Goal statements involving the context element "includes" no longer
   289     generate theorems with internal delta predicates (those ending on
   290     "_axioms") in the premise.
   291     Resolve particular premise with <locale>.intro to obtain old form.
   292   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   293     specification and "includes" elements in goal statement.
   294   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   295     [intro?] and [elim?] (respectively) by default.
   296   - Experimental command for instantiation of locales in proof contexts:
   297         instantiate <label>[<attrs>]: <loc>
   298     Instantiates locale <loc> and adds all its theorems to the current context
   299     taking into account their attributes.  Label and attrs are optional
   300     modifiers, like in theorem declarations.  If present, names of
   301     instantiated theorems are qualified with <label>, and the attributes
   302     <attrs> are applied after any attributes these theorems might have already.
   303       If the locale has assumptions, a chained fact of the form
   304     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   305     are derived.  The command does not support old-style locales declared
   306     with "locale (open)".
   307       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   308 
   309 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   310   (Isar) contexts.
   311 
   312 
   313 *** HOL ***
   314 
   315 * Proof import: new image HOL4 contains the imported library from
   316   the HOL4 system with about 2500 theorems. It is imported by
   317   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   318   can be used like any other Isabelle image.  See
   319   HOL/Import/HOL/README for more information.
   320 
   321 * Simplifier:
   322   - Much improved handling of linear and partial orders.
   323     Reasoners for linear and partial orders are set up for type classes
   324     "linorder" and "order" respectively, and are added to the default simpset
   325     as solvers.  This means that the simplifier can build transitivity chains
   326     to solve goals from the assumptions.
   327   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   328     of blast or auto after simplification become unnecessary because the goal
   329     is solved by simplification already.
   330 
   331 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   332     all proved in axiomatic type classes for semirings, rings and fields.
   333 
   334 * Numerics:
   335   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   336     now formalized using the Ring_and_Field theory mentioned above.
   337   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   338     than before, because now they are set up once in a generic manner.
   339   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   340     Look for the general versions in Ring_and_Field (and Power if they concern
   341     exponentiation).
   342 
   343 * Type "rat" of the rational numbers is now available in HOL-Complex.
   344 
   345 * Records:
   346   - Record types are now by default printed with their type abbreviation
   347     instead of the list of all field types. This can be configured via
   348     the reference "print_record_type_abbr".
   349   - Simproc "record_upd_simproc" for simplification of multiple updates added
   350     (not enabled by default).
   351   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   352     EX x. x = sel r to True (not enabled by default).
   353   - Tactic "record_split_simp_tac" to split and simplify records added.
   354 
   355 * 'specification' command added, allowing for definition by
   356   specification.  There is also an 'ax_specification' command that
   357   introduces the new constants axiomatically.
   358 
   359 * arith(_tac) is now able to generate counterexamples for reals as well.
   360 
   361 * HOL-Algebra: new locale "ring" for non-commutative rings.
   362 
   363 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   364   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   365 
   366 * HOL-Matrix: a first theory for matrices in HOL with an application of
   367   matrix theory to linear programming.
   368 
   369 * Unions and Intersections:
   370   The x-symbol output syntax of UN and INT has been changed
   371   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   372   i.e. the index formulae has become a subscript, like in normal math.
   373   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   374   The subscript version is also accepted as input syntax.
   375 
   376 * Unions and Intersections over Intervals:
   377   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   378   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   379   like in normal math, and corresponding versions for < and for intersection.
   380 
   381 * ML: the legacy theory structures Int and List have been removed. They had
   382   conflicted with ML Basis Library structures having the same names.
   383 
   384 * 'refute' command added to search for (finite) countermodels.  Only works
   385   for a fragment of HOL.  The installation of an external SAT solver is
   386   highly recommended.  See "HOL/Refute.thy" for details.
   387 
   388 * 'quickcheck' command: Allows to find counterexamples by evaluating
   389   formulae under an assignment of free variables to random values.
   390   In contrast to 'refute', it can deal with inductive datatypes,
   391   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   392   for examples.
   393 
   394 
   395 *** HOLCF ***
   396 
   397 * Streams now come with concatenation and are part of the HOLCF image
   398 
   399 
   400 
   401 New in Isabelle2003 (May 2003)
   402 ------------------------------
   403 
   404 *** General ***
   405 
   406 * Provers/simplifier:
   407 
   408   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   409     Assumptions are now subject to complete mutual simplification,
   410     not just from left to right. The simplifier now preserves
   411     the order of assumptions.
   412 
   413     Potential INCOMPATIBILITY:
   414 
   415     -- simp sometimes diverges where the old version did
   416        not, e.g. invoking simp on the goal
   417 
   418         [| P (f x); y = x; f x = f y |] ==> Q
   419 
   420        now gives rise to the infinite reduction sequence
   421 
   422         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   423 
   424        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   425        kind of problem.
   426 
   427     -- Tactics combining classical reasoner and simplification (such as auto)
   428        are also affected by this change, because many of them rely on
   429        simp. They may sometimes diverge as well or yield a different numbers
   430        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   431        in case of problems. Sometimes subsequent calls to the classical
   432        reasoner will fail because a preceeding call to the simplifier too
   433        eagerly simplified the goal, e.g. deleted redundant premises.
   434 
   435   - The simplifier trace now shows the names of the applied rewrite rules
   436 
   437   - You can limit the number of recursive invocations of the simplifier
   438     during conditional rewriting (where the simplifie tries to solve the
   439     conditions before applying the rewrite rule):
   440     ML "simp_depth_limit := n"
   441     where n is an integer. Thus you can force termination where previously
   442     the simplifier would diverge.
   443 
   444   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   445 
   446   - No longer aborts on failed congruence proof.  Instead, the
   447     congruence is ignored.
   448 
   449 * Pure: New generic framework for extracting programs from constructive
   450   proofs. See HOL/Extraction.thy for an example instantiation, as well
   451   as HOL/Extraction for some case studies.
   452 
   453 * Pure: The main goal of the proof state is no longer shown by default, only
   454 the subgoals. This behaviour is controlled by a new flag.
   455    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   456 (ML: Proof.show_main_goal).
   457 
   458 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   459 rules whose conclusion matches subgoal 1:
   460       PG menu: Isabelle/Isar -> Show me -> matching rules
   461 The rules are ordered by how closely they match the subgoal.
   462 In particular, rules that solve a subgoal outright are displayed first
   463 (or rather last, the way they are printed).
   464 (ML: ProofGeneral.print_intros())
   465 
   466 * Pure: New flag trace_unify_fail causes unification to print
   467 diagnostic information (PG: in trace buffer) when it fails. This is
   468 useful for figuring out why single step proofs like rule, erule or
   469 assumption failed.
   470 
   471 * Pure: Locale specifications now produce predicate definitions
   472 according to the body of text (covering assumptions modulo local
   473 definitions); predicate "loc_axioms" covers newly introduced text,
   474 while "loc" is cumulative wrt. all included locale expressions; the
   475 latter view is presented only on export into the global theory
   476 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   477 on the old view without predicates;
   478 
   479 * Pure: predefined locales "var" and "struct" are useful for sharing
   480 parameters (as in CASL, for example); just specify something like
   481 ``var x + var y + struct M'' as import;
   482 
   483 * Pure: improved thms_containing: proper indexing of facts instead of
   484 raw theorems; check validity of results wrt. current name space;
   485 include local facts of proof configuration (also covers active
   486 locales), cover fixed variables in index; may use "_" in term
   487 specification; an optional limit for the number of printed facts may
   488 be given (the default is 40);
   489 
   490 * Pure: disallow duplicate fact bindings within new-style theory files
   491 (batch-mode only);
   492 
   493 * Provers: improved induct method: assumptions introduced by case
   494 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   495 the goal statement); "foo" still refers to all facts collectively;
   496 
   497 * Provers: the function blast.overloaded has been removed: all constants
   498 are regarded as potentially overloaded, which improves robustness in exchange
   499 for slight decrease in efficiency;
   500 
   501 * Provers/linorder: New generic prover for transitivity reasoning over
   502 linear orders.  Note: this prover is not efficient!
   503 
   504 * Isar: preview of problems to finish 'show' now produce an error
   505 rather than just a warning (in interactive mode);
   506 
   507 
   508 *** HOL ***
   509 
   510 * arith(_tac)
   511 
   512  - Produces a counter example if it cannot prove a goal.
   513    Note that the counter example may be spurious if the goal is not a formula
   514    of quantifier-free linear arithmetic.
   515    In ProofGeneral the counter example appears in the trace buffer.
   516 
   517  - Knows about div k and mod k where k is a numeral of type nat or int.
   518 
   519  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   520    linear arithmetic fails. This takes account of quantifiers and divisibility.
   521    Presburger arithmetic can also be called explicitly via presburger(_tac).
   522 
   523 * simp's arithmetic capabilities have been enhanced a bit: it now
   524 takes ~= in premises into account (by performing a case split);
   525 
   526 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   527 are distributed over a sum of terms;
   528 
   529 * New tactic "trans_tac" and method "trans" instantiate
   530 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   531 "<=", "<" and "=").
   532 
   533 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   534 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   535 
   536 * 'typedef' command has new option "open" to suppress the set
   537 definition;
   538 
   539 * functions Min and Max on finite sets have been introduced (theory
   540 Finite_Set);
   541 
   542 * attribute [symmetric] now works for relations as well; it turns
   543 (x,y) : R^-1 into (y,x) : R, and vice versa;
   544 
   545 * induct over a !!-quantified statement (say !!x1..xn):
   546   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   547 
   548 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   549 %x. None. Warning: empty_def now refers to the previously hidden definition
   550 of the empty set.
   551 
   552 * Algebra: formalization of classical algebra.  Intended as base for
   553 any algebraic development in Isabelle.  Currently covers group theory
   554 (up to Sylow's theorem) and ring theory (Universal Property of
   555 Univariate Polynomials).  Contributions welcome;
   556 
   557 * GroupTheory: deleted, since its material has been moved to Algebra;
   558 
   559 * Complex: new directory of the complex numbers with numeric constants,
   560 nonstandard complex numbers, and some complex analysis, standard and
   561 nonstandard (Jacques Fleuriot);
   562 
   563 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   564 
   565 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   566 Fleuriot);
   567 
   568 * Real/HahnBanach: updated and adapted to locales;
   569 
   570 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   571 Gray and Kramer);
   572 
   573 * UNITY: added the Meier-Sanders theory of progress sets;
   574 
   575 * MicroJava: bytecode verifier and lightweight bytecode verifier
   576 as abstract algorithms, instantiated to the JVM;
   577 
   578 * Bali: Java source language formalization. Type system, operational
   579 semantics, axiomatic semantics. Supported language features:
   580 classes, interfaces, objects,virtual methods, static methods,
   581 static/instance fields, arrays, access modifiers, definite
   582 assignment, exceptions.
   583 
   584 
   585 *** ZF ***
   586 
   587 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   588 universe, etc.);
   589 
   590 * Main ZF: virtually all theories converted to new-style format;
   591 
   592 
   593 *** ML ***
   594 
   595 * Pure: Tactic.prove provides sane interface for internal proofs;
   596 omits the infamous "standard" operation, so this is more appropriate
   597 than prove_goalw_cterm in many situations (e.g. in simprocs);
   598 
   599 * Pure: improved error reporting of simprocs;
   600 
   601 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   602 up simprocs;
   603 
   604 
   605 *** Document preparation ***
   606 
   607 * uses \par instead of \\ for line breaks in theory text. This may
   608 shift some page breaks in large documents. To get the old behaviour
   609 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   610 
   611 * minimized dependencies of isabelle.sty and isabellesym.sty on
   612 other packages
   613 
   614 * \<euro> now needs package babel/greek instead of marvosym (which
   615 broke \Rightarrow)
   616 
   617 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   618 textcomp package)
   619 
   620 
   621 
   622 New in Isabelle2002 (March 2002)
   623 --------------------------------
   624 
   625 *** Document preparation ***
   626 
   627 * greatly simplified document preparation setup, including more
   628 graceful interpretation of isatool usedir -i/-d/-D options, and more
   629 instructive isatool mkdir; users should basically be able to get
   630 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   631 users may run a separate document processing stage manually like this:
   632 "isatool usedir -D output HOL Test && isatool document Test/output";
   633 
   634 * theory dependency graph may now be incorporated into documents;
   635 isatool usedir -g true will produce session_graph.eps/.pdf for use
   636 with \includegraphics of LaTeX;
   637 
   638 * proper spacing of consecutive markup elements, especially text
   639 blocks after section headings;
   640 
   641 * support bold style (for single symbols only), input syntax is like
   642 this: "\<^bold>\<alpha>" or "\<^bold>A";
   643 
   644 * \<bullet> is now output as bold \cdot by default, which looks much
   645 better in printed text;
   646 
   647 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   648 note that these symbols are currently unavailable in Proof General /
   649 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   650 
   651 * isatool latex no longer depends on changed TEXINPUTS, instead
   652 isatool document copies the Isabelle style files to the target
   653 location;
   654 
   655 
   656 *** Isar ***
   657 
   658 * Pure/Provers: improved proof by cases and induction;
   659   - 'case' command admits impromptu naming of parameters (such as
   660     "case (Suc n)");
   661   - 'induct' method divinates rule instantiation from the inductive
   662     claim; no longer requires excessive ?P bindings for proper
   663     instantiation of cases;
   664   - 'induct' method properly enumerates all possibilities of set/type
   665     rules; as a consequence facts may be also passed through *type*
   666     rules without further ado;
   667   - 'induct' method now derives symbolic cases from the *rulified*
   668     rule (before it used to rulify cases stemming from the internal
   669     atomized version); this means that the context of a non-atomic
   670     statement becomes is included in the hypothesis, avoiding the
   671     slightly cumbersome show "PROP ?case" form;
   672   - 'induct' may now use elim-style induction rules without chaining
   673     facts, using ``missing'' premises from the goal state; this allows
   674     rules stemming from inductive sets to be applied in unstructured
   675     scripts, while still benefitting from proper handling of non-atomic
   676     statements; NB: major inductive premises need to be put first, all
   677     the rest of the goal is passed through the induction;
   678   - 'induct' proper support for mutual induction involving non-atomic
   679     rule statements (uses the new concept of simultaneous goals, see
   680     below);
   681   - append all possible rule selections, but only use the first
   682     success (no backtracking);
   683   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   684   - undeclared rule case names default to numbers 1, 2, 3, ...;
   685   - added 'print_induct_rules' (covered by help item in recent Proof
   686     General versions);
   687   - moved induct/cases attributes to Pure, methods to Provers;
   688   - generic method setup instantiated for FOL and HOL;
   689 
   690 * Pure: support multiple simultaneous goal statements, for example
   691 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   692 meta-level mechanism, this acts as if several individual goals had
   693 been stated separately; in particular common proof methods need to be
   694 repeated in order to cover all claims; note that a single elimination
   695 step is *not* sufficient to establish the two conjunctions, so this
   696 fails:
   697 
   698   assume "A & B" then have A and B ..   (*".." fails*)
   699 
   700 better use "obtain" in situations as above; alternative refer to
   701 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   702 
   703 * Pure: proper integration with ``locales''; unlike the original
   704 version by Florian Kammüller, Isar locales package high-level proof
   705 contexts rather than raw logical ones (e.g. we admit to include
   706 attributes everywhere); operations on locales include merge and
   707 rename; support for implicit arguments (``structures''); simultaneous
   708 type-inference over imports and text; see also HOL/ex/Locales.thy for
   709 some examples;
   710 
   711 * Pure: the following commands have been ``localized'', supporting a
   712 target locale specification "(in name)": 'lemma', 'theorem',
   713 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   714 stored both within the locale and at the theory level (exported and
   715 qualified by the locale name);
   716 
   717 * Pure: theory goals may now be specified in ``long'' form, with
   718 ad-hoc contexts consisting of arbitrary locale elements. for example
   719 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   720 definitions may be given, too); the result is a meta-level rule with
   721 the context elements being discharged in the obvious way;
   722 
   723 * Pure: new proof command 'using' allows to augment currently used
   724 facts after a goal statement ('using' is syntactically analogous to
   725 'apply', but acts on the goal's facts only); this allows chained facts
   726 to be separated into parts given before and after a claim, as in
   727 ``from a and b have C using d and e <proof>'';
   728 
   729 * Pure: renamed "antecedent" case to "rule_context";
   730 
   731 * Pure: new 'judgment' command records explicit information about the
   732 object-logic embedding (used by several tools internally); no longer
   733 use hard-wired "Trueprop";
   734 
   735 * Pure: added 'corollary' command;
   736 
   737 * Pure: fixed 'token_translation' command;
   738 
   739 * Pure: removed obsolete 'exported' attribute;
   740 
   741 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   742 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   743 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   744 
   745 * Pure: method 'atomize' presents local goal premises as object-level
   746 statements (atomic meta-level propositions); setup controlled via
   747 rewrite rules declarations of 'atomize' attribute; example
   748 application: 'induct' method with proper rule statements in improper
   749 proof *scripts*;
   750 
   751 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   752 now consider the syntactic context of assumptions, giving a better
   753 chance to get type-inference of the arguments right (this is
   754 especially important for locales);
   755 
   756 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   757 mode;
   758 
   759 * Pure/obtain: the formal conclusion "thesis", being marked as
   760 ``internal'', may no longer be reference directly in the text;
   761 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   762 situations;
   763 
   764 * Pure: generic 'sym' attribute which declares a rule both as pure
   765 'elim?' and for the 'symmetric' operation;
   766 
   767 * Pure: marginal comments ``--'' may now occur just anywhere in the
   768 text; the fixed correlation with particular command syntax has been
   769 discontinued;
   770 
   771 * Pure: new method 'rules' is particularly well-suited for proof
   772 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   773 but often produces more compact proof terms with less detours;
   774 
   775 * Pure/Provers/classical: simplified integration with pure rule
   776 attributes and methods; the classical "intro?/elim?/dest?"
   777 declarations coincide with the pure ones; the "rule" method no longer
   778 includes classically swapped intros; "intro" and "elim" methods no
   779 longer pick rules from the context; also got rid of ML declarations
   780 AddXIs/AddXEs/AddXDs; all of this has some potential for
   781 INCOMPATIBILITY;
   782 
   783 * Provers/classical: attribute 'swapped' produces classical inversions
   784 of introduction rules;
   785 
   786 * Provers/simplifier: 'simplified' attribute may refer to explicit
   787 rules instead of full simplifier context; 'iff' attribute handles
   788 conditional rules;
   789 
   790 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   791 
   792 * HOL: 'recdef' now fails on unfinished automated proofs, use
   793 "(permissive)" option to recover old behavior;
   794 
   795 * HOL: 'inductive' no longer features separate (collective) attributes
   796 for 'intros' (was found too confusing);
   797 
   798 * HOL: properly declared induction rules less_induct and
   799 wf_induct_rule;
   800 
   801 
   802 *** HOL ***
   803 
   804 * HOL: moved over to sane numeral syntax; the new policy is as
   805 follows:
   806 
   807   - 0 and 1 are polymorphic constants, which are defined on any
   808   numeric type (nat, int, real etc.);
   809 
   810   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   811   binary representation internally;
   812 
   813   - type nat has special constructor Suc, and generally prefers Suc 0
   814   over 1::nat and Suc (Suc 0) over 2::nat;
   815 
   816 This change may cause significant problems of INCOMPATIBILITY; here
   817 are some hints on converting existing sources:
   818 
   819   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   820   entities, so expressions involving "-" (unary or binary minus) need
   821   to be spaced properly;
   822 
   823   - existing occurrences of "1" may need to be constraint "1::nat" or
   824   even replaced by Suc 0; similar for old "2";
   825 
   826   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   827 
   828   - remove all special provisions on numerals in proofs;
   829 
   830 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   831 representation (depends on bin_arith_simps in the default context);
   832 
   833 * HOL: symbolic syntax for x^2 (numeral 2);
   834 
   835 * HOL: the class of all HOL types is now called "type" rather than
   836 "term"; INCOMPATIBILITY, need to adapt references to this type class
   837 in axclass/classes, instance/arities, and (usually rare) occurrences
   838 in typings (of consts etc.); internally the class is called
   839 "HOL.type", ML programs should refer to HOLogic.typeS;
   840 
   841 * HOL/record package improvements:
   842   - new derived operations "fields" to build a partial record section,
   843     "extend" to promote a fixed record to a record scheme, and
   844     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   845     declared as simp by default;
   846   - shared operations ("more", "fields", etc.) now need to be always
   847     qualified) --- potential INCOMPATIBILITY;
   848   - removed "make_scheme" operations (use "make" with "extend") --
   849     INCOMPATIBILITY;
   850   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   851   - provides cases/induct rules for use with corresponding Isar
   852     methods (for concrete records, record schemes, concrete more
   853     parts, and schematic more parts -- in that order);
   854   - internal definitions directly based on a light-weight abstract
   855     theory of product types over typedef rather than datatype;
   856 
   857 * HOL: generic code generator for generating executable ML code from
   858 specifications; specific support for HOL constructs such as inductive
   859 datatypes and sets, as well as recursive functions; can be invoked
   860 via 'generate_code' theory section;
   861 
   862 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   863 
   864 * HOL: consolidated and renamed several theories.  In particular:
   865         Ord.thy has been absorbed into HOL.thy
   866         String.thy has been absorbed into List.thy
   867 
   868 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   869 (beware of argument permutation!);
   870 
   871 * HOL: linorder_less_split superseded by linorder_cases;
   872 
   873 * HOL/List: "nodups" renamed to "distinct";
   874 
   875 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   876 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   877   - Ex_def has changed, now need to use some_eq_ex
   878 
   879 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   880 in this (rare) case use:
   881 
   882   delSWrapper "split_all_tac"
   883   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   884 
   885 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   886 MAY FAIL;
   887 
   888 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   889 Isabelle's type classes, ^ on functions and relations has too general
   890 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   891 necessary to attach explicit type constraints;
   892 
   893 * HOL/Relation: the prefix name of the infix "O" has been changed from
   894 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   895 renamed accordingly (eg "compI" -> "rel_compI").
   896 
   897 * HOL: syntax translations now work properly with numerals and records
   898 expressions;
   899 
   900 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   901 of "lam" -- INCOMPATIBILITY;
   902 
   903 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   904 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   905 renamed "Product_Type.unit";
   906 
   907 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   908 
   909 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   910 the "cases" method);
   911 
   912 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   913 Florian Kammüller);
   914 
   915 * HOL/IMP: updated and converted to new-style theory format; several
   916 parts turned into readable document, with proper Isar proof texts and
   917 some explanations (by Gerwin Klein);
   918 
   919 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   920 
   921 * HOL-Hyperreal is now a logic image;
   922 
   923 
   924 *** HOLCF ***
   925 
   926 * Isar: consts/constdefs supports mixfix syntax for continuous
   927 operations;
   928 
   929 * Isar: domain package adapted to new-style theory format, e.g. see
   930 HOLCF/ex/Dnat.thy;
   931 
   932 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   933 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   934 lift.induct_tac, always use UU instead of Undef;
   935 
   936 * HOLCF/IMP: updated and converted to new-style theory;
   937 
   938 
   939 *** ZF ***
   940 
   941 * Isar: proper integration of logic-specific tools and packages,
   942 including theory commands '(co)inductive', '(co)datatype',
   943 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   944 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   945 
   946 * theory Main no longer includes AC; for the Axiom of Choice, base
   947 your theory on Main_ZFC;
   948 
   949 * the integer library now covers quotients and remainders, with many
   950 laws relating division to addition, multiplication, etc.;
   951 
   952 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   953 typeless version of the formalism;
   954 
   955 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   956 format;
   957 
   958 * ZF/Induct: new directory for examples of inductive definitions,
   959 including theory Multiset for multiset orderings; converted to
   960 new-style theory format;
   961 
   962 * ZF: many new theorems about lists, ordinals, etc.;
   963 
   964 
   965 *** General ***
   966 
   967 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   968 variable proof controls level of detail: 0 = no proofs (only oracle
   969 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   970 also ref manual for further ML interfaces;
   971 
   972 * Pure/axclass: removed obsolete ML interface
   973 goal_subclass/goal_arity;
   974 
   975 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   976 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   977 separate tokens, so expressions involving minus need to be spaced
   978 properly;
   979 
   980 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   981 rather than "infixl" or "infixr";
   982 
   983 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   984 sort constraint specifications in type inference; e.g. "x::_::foo"
   985 ensures that the type of "x" is of sort "foo" (but not necessarily a
   986 type variable);
   987 
   988 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   989 control output of nested => (types); the default behavior is
   990 "type_brackets";
   991 
   992 * Pure/syntax: builtin parse translation for "_constify" turns valued
   993 tokens into AST constants;
   994 
   995 * Pure/syntax: prefer later declarations of translations and print
   996 translation functions; potential INCOMPATIBILITY: need to reverse
   997 multiple declarations for same syntax element constant;
   998 
   999 * Pure/show_hyps reset by default (in accordance to existing Isar
  1000 practice);
  1001 
  1002 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1003 addSafter;
  1004 
  1005 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1006 as well;
  1007 
  1008 * system: tested support for MacOS X; should be able to get Isabelle +
  1009 Proof General to work in a plain Terminal after installing Poly/ML
  1010 (e.g. from the Isabelle distribution area) and GNU bash alone
  1011 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1012 support requires further installations, e.g. from
  1013 http://fink.sourceforge.net/);
  1014 
  1015 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1016 
  1017 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1018 of 40 MB), cf. ML_OPTIONS;
  1019 
  1020 * system: Proof General keywords specification is now part of the
  1021 Isabelle distribution (see etc/isar-keywords.el);
  1022 
  1023 * system: support for persistent Proof General sessions (refrain from
  1024 outdating all loaded theories on startup); user may create writable
  1025 logic images like this: ``isabelle -q HOL Test'';
  1026 
  1027 * system: smart selection of Isabelle process versus Isabelle
  1028 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1029 run both "isabelle" and "Isabelle" even if file names are badly
  1030 damaged (executable inspects the case of the first letter of its own
  1031 name); added separate "isabelle-process" and "isabelle-interface";
  1032 
  1033 * system: refrain from any attempt at filtering input streams; no
  1034 longer support ``8bit'' encoding of old isabelle font, instead proper
  1035 iso-latin characters may now be used; the related isatools
  1036 "symbolinput" and "nonascii" have disappeared as well;
  1037 
  1038 * system: removed old "xterm" interface (the print modes "xterm" and
  1039 "xterm_color" are still available for direct use in a suitable
  1040 terminal);
  1041 
  1042 
  1043 
  1044 New in Isabelle99-2 (February 2001)
  1045 -----------------------------------
  1046 
  1047 *** Overview of INCOMPATIBILITIES ***
  1048 
  1049 * HOL: please note that theories in the Library and elsewhere often use the
  1050 new-style (Isar) format; to refer to their theorems in an ML script you must
  1051 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1052 
  1053 * HOL: inductive package no longer splits induction rule aggressively,
  1054 but only as far as specified by the introductions given; the old
  1055 format may be recovered via ML function complete_split_rule or attribute
  1056 'split_rule (complete)';
  1057 
  1058 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1059 gfp_Tarski to gfp_unfold;
  1060 
  1061 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1062 
  1063 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1064 relation); infix "^^" has been renamed "``"; infix "``" has been
  1065 renamed "`"; "univalent" has been renamed "single_valued";
  1066 
  1067 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1068 operation;
  1069 
  1070 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1071 
  1072 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1073 
  1074 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1075 consequence, it is no longer monotonic wrt. the local goal context
  1076 (which is now passed through the inductive cases);
  1077 
  1078 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1079 \<gg> to \<ggreater>;
  1080 
  1081 
  1082 *** Document preparation ***
  1083 
  1084 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1085 available: are "it" for near math-mode best-style output, "sl" for
  1086 slanted text style, and "tt" for plain type-writer; if no
  1087 \isabellestyle command is given, output is according to slanted
  1088 type-writer);
  1089 
  1090 * support sub/super scripts (for single symbols only), input syntax is
  1091 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1092 
  1093 * some more standard symbols; see Appendix A of the system manual for
  1094 the complete list of symbols defined in isabellesym.sty;
  1095 
  1096 * improved isabelle style files; more abstract symbol implementation
  1097 (should now use \isamath{...} and \isatext{...} in custom symbol
  1098 definitions);
  1099 
  1100 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1101 state; Note that presentation of goal states does not conform to
  1102 actual human-readable proof documents.  Please do not include goal
  1103 states into document output unless you really know what you are doing!
  1104 
  1105 * proper indentation of antiquoted output with proportional LaTeX
  1106 fonts;
  1107 
  1108 * no_document ML operator temporarily disables LaTeX document
  1109 generation;
  1110 
  1111 * isatool unsymbolize tunes sources for plain ASCII communication;
  1112 
  1113 
  1114 *** Isar ***
  1115 
  1116 * Pure: Isar now suffers initial goal statements to contain unbound
  1117 schematic variables (this does not conform to actual readable proof
  1118 documents, due to unpredictable outcome and non-compositional proof
  1119 checking); users who know what they are doing may use schematic goals
  1120 for Prolog-style synthesis of proven results;
  1121 
  1122 * Pure: assumption method (an implicit finishing) now handles actual
  1123 rules as well;
  1124 
  1125 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1126 initial goal, declare "that" only as Pure intro (only for single
  1127 steps); the "that" rule assumption may now be involved in implicit
  1128 finishing, thus ".." becomes a feasible for trivial obtains;
  1129 
  1130 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1131 instance proofs may be performed by "..";
  1132 
  1133 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1134 statements as well;
  1135 
  1136 * Pure: more robust selection of calculational rules;
  1137 
  1138 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1139 rule (as well as the assumption rule);
  1140 
  1141 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1142 lemmas, using the graph browser tool;
  1143 
  1144 * Pure: predict failure of "show" in interactive mode;
  1145 
  1146 * Pure: 'thms_containing' now takes actual terms as arguments;
  1147 
  1148 * HOL: improved method 'induct' --- now handles non-atomic goals
  1149 (potential INCOMPATIBILITY); tuned error handling;
  1150 
  1151 * HOL: cases and induct rules now provide explicit hints about the
  1152 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1153 any remaining facts are inserted into the goal verbatim;
  1154 
  1155 * HOL: local contexts (aka cases) may now contain term bindings as
  1156 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1157 the result to be shown in each case;
  1158 
  1159 * HOL: added 'recdef_tc' command;
  1160 
  1161 * isatool convert assists in eliminating legacy ML scripts;
  1162 
  1163 
  1164 *** HOL ***
  1165 
  1166 * HOL/Library: a collection of generic theories to be used together
  1167 with main HOL; the theory loader path already includes this directory
  1168 by default; the following existing theories have been moved here:
  1169 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1170 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1171 
  1172 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1173 modelling and verification task performed in Isabelle/HOL +
  1174 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1175 
  1176 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1177 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1178 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1179 'domain', this makes the theory consistent with mathematical
  1180 literature;
  1181 
  1182 * HOL basics: added overloaded operations "inverse" and "divide"
  1183 (infix "/"), syntax for generic "abs" operation, generic summation
  1184 operator \<Sum>;
  1185 
  1186 * HOL/typedef: simplified package, provide more useful rules (see also
  1187 HOL/subset.thy);
  1188 
  1189 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1190 now expressed as a proper nested rule (old-style tactic scripts may
  1191 require atomize_strip_tac to cope with non-atomic premises);
  1192 
  1193 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1194 to "split_conv" (old name still available for compatibility);
  1195 
  1196 * HOL: improved concrete syntax for strings (e.g. allows translation
  1197 rules with string literals);
  1198 
  1199 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1200  and Fleuriot's mechanization of analysis, including the transcendental
  1201  functions for the reals;
  1202 
  1203 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1204 
  1205 
  1206 *** CTT ***
  1207 
  1208 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1209 "lam" is displayed as TWO lambda-symbols
  1210 
  1211 * CTT: theory Main now available, containing everything (that is, Bool
  1212 and Arith);
  1213 
  1214 
  1215 *** General ***
  1216 
  1217 * Pure: the Simplifier has been implemented properly as a derived rule
  1218 outside of the actual kernel (at last!); the overall performance
  1219 penalty in practical applications is about 50%, while reliability of
  1220 the Isabelle inference kernel has been greatly improved;
  1221 
  1222 * print modes "brackets" and "no_brackets" control output of nested =>
  1223 (types) and ==> (props); the default behaviour is "brackets";
  1224 
  1225 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1226 as assumptions as well;
  1227 
  1228 * system: support Poly/ML 4.0;
  1229 
  1230 * system: isatool install handles KDE version 1 or 2;
  1231 
  1232 
  1233 
  1234 New in Isabelle99-1 (October 2000)
  1235 ----------------------------------
  1236 
  1237 *** Overview of INCOMPATIBILITIES ***
  1238 
  1239 * HOL: simplification of natural numbers is much changed; to partly
  1240 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1241 issue the following ML commands:
  1242 
  1243   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1244   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1245 
  1246 * HOL: simplification no longer dives into case-expressions; this is
  1247 controlled by "t.weak_case_cong" for each datatype t;
  1248 
  1249 * HOL: nat_less_induct renamed to less_induct;
  1250 
  1251 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1252 fixsome to patch .thy and .ML sources automatically;
  1253 
  1254   select_equality  -> some_equality
  1255   select_eq_Ex     -> some_eq_ex
  1256   selectI2EX       -> someI2_ex
  1257   selectI2         -> someI2
  1258   selectI          -> someI
  1259   select1_equality -> some1_equality
  1260   Eps_sym_eq       -> some_sym_eq_trivial
  1261   Eps_eq           -> some_eq_trivial
  1262 
  1263 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1264 
  1265 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1266 instead);
  1267 
  1268 * HOL: the recursion equations generated by 'recdef' are now called
  1269 f.simps instead of f.rules;
  1270 
  1271 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1272 
  1273 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1274 sometimes be needed;
  1275 
  1276 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1277 
  1278 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1279 
  1280 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1281 product is now "<*>" instead of "Times"; the lexicographic product is
  1282 now "<*lex*>" instead of "**";
  1283 
  1284 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1285 of main HOL, but was unused); better use HOL's datatype package;
  1286 
  1287 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1288 the old syntax may be recovered as follows:
  1289 
  1290   syntax (symbols)
  1291     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1292       (infixl "\\<oplus>" 100)
  1293 
  1294 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1295 
  1296 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1297 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1298 internally;
  1299 
  1300 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1301 changed from A/r to A//r;
  1302 
  1303 * ZF: new treatment of arithmetic (nat & int) may break some old
  1304 proofs;
  1305 
  1306 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1307 rulify -> rule_format, elimify -> elim_format, ...);
  1308 
  1309 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1310 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1311 should have to change intro!! to intro? only); replaced "delrule" by
  1312 "rule del";
  1313 
  1314 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1315 
  1316 * Provers: strengthened force_tac by using new first_best_tac;
  1317 
  1318 * LaTeX document preparation: several changes of isabelle.sty (see
  1319 lib/texinputs);
  1320 
  1321 
  1322 *** Document preparation ***
  1323 
  1324 * formal comments (text blocks etc.) in new-style theories may now
  1325 contain antiquotations of thm/prop/term/typ/text to be presented
  1326 according to latex print mode; concrete syntax is like this:
  1327 @{term[show_types] "f(x) = a + x"};
  1328 
  1329 * isatool mkdir provides easy setup of Isabelle session directories,
  1330 including proper document sources;
  1331 
  1332 * generated LaTeX sources are now deleted after successful run
  1333 (isatool document -c); may retain a copy somewhere else via -D option
  1334 of isatool usedir;
  1335 
  1336 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1337 style files, achieving self-contained LaTeX sources and simplifying
  1338 LaTeX debugging;
  1339 
  1340 * old-style theories now produce (crude) LaTeX output as well;
  1341 
  1342 * browser info session directories are now self-contained (may be put
  1343 on WWW server seperately); improved graphs of nested sessions; removed
  1344 graph for 'all sessions';
  1345 
  1346 * several improvements in isabelle style files; \isabellestyle{it}
  1347 produces fake math mode output; \isamarkupheader is now \section by
  1348 default; see lib/texinputs/isabelle.sty etc.;
  1349 
  1350 
  1351 *** Isar ***
  1352 
  1353 * Isar/Pure: local results and corresponding term bindings are now
  1354 subject to Hindley-Milner polymorphism (similar to ML); this
  1355 accommodates incremental type-inference very nicely;
  1356 
  1357 * Isar/Pure: new derived language element 'obtain' supports
  1358 generalized existence reasoning;
  1359 
  1360 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1361 support accumulation of results, without applying any rules yet;
  1362 useful to collect intermediate results without explicit name
  1363 references, and for use with transitivity rules with more than 2
  1364 premises;
  1365 
  1366 * Isar/Pure: scalable support for case-analysis type proofs: new
  1367 'case' language element refers to local contexts symbolically, as
  1368 produced by certain proof methods; internally, case names are attached
  1369 to theorems as "tags";
  1370 
  1371 * Isar/Pure: theory command 'hide' removes declarations from
  1372 class/type/const name spaces;
  1373 
  1374 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1375 indicate potential overloading;
  1376 
  1377 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1378 
  1379 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1380 "{a,b,c}" instead of {a,b,c};
  1381 
  1382 * Isar/Pure now provides its own version of intro/elim/dest
  1383 attributes; useful for building new logics, but beware of confusion
  1384 with the version in Provers/classical;
  1385 
  1386 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1387 case name 'antecedent';
  1388 
  1389 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1390 to the current context is now done automatically);
  1391 
  1392 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1393 for definining proof methods in ML;
  1394 
  1395 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1396 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1397 most cases, one should have to change intro!! to intro? only);
  1398 replaced "delrule" by "rule del";
  1399 
  1400 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1401 'symmetric' attribute (the latter supercedes [RS sym]);
  1402 
  1403 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1404 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1405 well (including splits);
  1406 
  1407 * Isar/Provers: Simplifier and Classical methods now support all kind
  1408 of modifiers used in the past, including 'cong', 'iff', etc.
  1409 
  1410 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1411 of Simplifier and Classical reasoner);
  1412 
  1413 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1414 now support named cases; major packages (inductive, datatype, primrec,
  1415 recdef) support case names and properly name parameters;
  1416 
  1417 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1418 monotonicity conditions are extracted to be proven at end of
  1419 calculations;
  1420 
  1421 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1422 method anyway;
  1423 
  1424 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1425 split_if split_if_asm; datatype package provides theorems foo.splits =
  1426 foo.split foo.split_asm for each datatype;
  1427 
  1428 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1429 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1430 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1431 use "(cases (simplified))" method in proper proof texts);
  1432 
  1433 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1434 
  1435 * Isar: names of theorems etc. may be natural numbers as well;
  1436 
  1437 * Isar: 'pr' command: optional arguments for goals_limit and
  1438 ProofContext.prems_limit; no longer prints theory contexts, but only
  1439 proof states;
  1440 
  1441 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1442 additional print modes to be specified; e.g. "pr(latex)" will print
  1443 proof state according to the Isabelle LaTeX style;
  1444 
  1445 * Isar: improved support for emulating tactic scripts, including proof
  1446 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1447 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1448 (for HOL datatypes);
  1449 
  1450 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1451 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1452 'proof method scripts' have to be in depth-first order;
  1453 
  1454 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1455 
  1456 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1457 should instead use individual commands for printing items
  1458 (print_commands, print_methods etc.);
  1459 
  1460 * Isar: added 'nothing' --- the empty list of theorems;
  1461 
  1462 
  1463 *** HOL ***
  1464 
  1465 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1466 corresponding virtual machine and a specification of its bytecode
  1467 verifier and a lightweight bytecode verifier, including proofs of
  1468 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1469 Cornelia Pusch (see also the homepage of project Bali at
  1470 http://isabelle.in.tum.de/Bali/);
  1471 
  1472 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1473 Clemens Ballarin;
  1474 
  1475 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1476 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1477 Rasmussen;
  1478 
  1479 * HOL/Lattice: fundamental concepts of lattice theory and order
  1480 structures, including duals, properties of bounds versus algebraic
  1481 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1482 Theorem for complete lattices etc.; may also serve as a demonstration
  1483 for abstract algebraic reasoning using axiomatic type classes, and
  1484 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1485 
  1486 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1487 von Oheimb;
  1488 
  1489 * HOL/IMPP: extension of IMP with local variables and mutually
  1490 recursive procedures, by David von Oheimb;
  1491 
  1492 * HOL/Lambda: converted into new-style theory and document;
  1493 
  1494 * HOL/ex/Multiquote: example of multiple nested quotations and
  1495 anti-quotations -- basically a generalized version of de-Bruijn
  1496 representation; very useful in avoiding lifting of operations;
  1497 
  1498 * HOL/record: added general record equality rule to simpset; fixed
  1499 select-update simplification procedure to handle extended records as
  1500 well; admit "r" as field name;
  1501 
  1502 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1503 other numeric types and also as the identity of groups, rings, etc.;
  1504 
  1505 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1506 Types nat and int belong to this axclass;
  1507 
  1508 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1509    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1510    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1511   two terms #m*u and #n*u are replaced by #(m+n)*u
  1512     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1513   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1514     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1515 
  1516 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1517 powerful prover for predicate logic but knows nothing of clasets; see
  1518 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1519 
  1520 * HOL: new version of "case_tac" subsumes both boolean case split and
  1521 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1522 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1523 
  1524 * HOL: simplification no longer dives into case-expressions: only the
  1525 selector expression is simplified, but not the remaining arms; to
  1526 enable full simplification of case-expressions for datatype t, you may
  1527 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1528 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1529 
  1530 * HOL/recdef: the recursion equations generated by 'recdef' for
  1531 function 'f' are now called f.simps instead of f.rules; if all
  1532 termination conditions are proved automatically, these simplification
  1533 rules are added to the simpset, as in primrec; rules may be named
  1534 individually as well, resulting in a separate list of theorems for
  1535 each equation;
  1536 
  1537 * HOL/While is a new theory that provides a while-combinator. It
  1538 permits the definition of tail-recursive functions without the
  1539 provision of a termination measure. The latter is necessary once the
  1540 invariant proof rule for while is applied.
  1541 
  1542 * HOL: new (overloaded) notation for the set of elements below/above
  1543 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1544 
  1545 * HOL: theorems impI, allI, ballI bound as "strip";
  1546 
  1547 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1548 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1549 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1550 
  1551 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1552 
  1553 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1554 main HOL, but was unused);
  1555 
  1556 * HOL: fewer consts declared as global (e.g. have to refer to
  1557 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1558 
  1559 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1560 in case of overlap with user translations (e.g. judgements over
  1561 tuples); (note that the underlying logical represenation is still
  1562 bogus);
  1563 
  1564 
  1565 *** ZF ***
  1566 
  1567 * ZF: simplification automatically cancels common terms in arithmetic
  1568 expressions over nat and int;
  1569 
  1570 * ZF: new treatment of nat to minimize type-checking: all operators
  1571 coerce their operands to a natural number using the function natify,
  1572 making the algebraic laws unconditional;
  1573 
  1574 * ZF: as above, for int: operators coerce their operands to an integer
  1575 using the function intify;
  1576 
  1577 * ZF: the integer library now contains many of the usual laws for the
  1578 orderings, including $<=, and monotonicity laws for $+ and $*;
  1579 
  1580 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1581 simplification;
  1582 
  1583 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1584 to the simplifier and classical reasoner simultaneously;
  1585 
  1586 
  1587 *** General ***
  1588 
  1589 * Provers: blast_tac now handles actual object-logic rules as
  1590 assumptions; note that auto_tac uses blast_tac internally as well;
  1591 
  1592 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1593 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1594 
  1595 * Provers: delrules now handles destruct rules as well (no longer need
  1596 explicit make_elim);
  1597 
  1598 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1599   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1600 use instead the strong form,
  1601   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1602 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1603 from destruct-rules;
  1604 
  1605 * Provers: Simplifier.easy_setup provides a fast path to basic
  1606 Simplifier setup for new object-logics;
  1607 
  1608 * Pure: AST translation rules no longer require constant head on LHS;
  1609 
  1610 * Pure: improved name spaces: ambiguous output is qualified; support
  1611 for hiding of names;
  1612 
  1613 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1614 XSYMBOL_HOME; no longer need to do manual configuration in most
  1615 situations;
  1616 
  1617 * system: compression of ML heaps images may now be controlled via -c
  1618 option of isabelle and isatool usedir (currently only observed by
  1619 Poly/ML);
  1620 
  1621 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1622 useful for remote X11);
  1623 
  1624 * system: provide TAGS file for Isabelle sources;
  1625 
  1626 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1627 order;
  1628 
  1629 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1630 timing flag supersedes proof_timing and Toplevel.trace;
  1631 
  1632 * ML: new combinators |>> and |>>> for incremental transformations
  1633 with secondary results (e.g. certain theory extensions):
  1634 
  1635 * ML: PureThy.add_defs gets additional argument to indicate potential
  1636 overloading (usually false);
  1637 
  1638 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1639 results;
  1640 
  1641 
  1642 
  1643 New in Isabelle99 (October 1999)
  1644 --------------------------------
  1645 
  1646 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1647 
  1648 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1649 are no longer simplified.  (This allows the simplifier to unfold recursive
  1650 functional programs.)  To restore the old behaviour, declare
  1651 
  1652     Delcongs [if_weak_cong];
  1653 
  1654 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1655 complement;
  1656 
  1657 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1658 
  1659 * HOL/datatype: mutual_induct_tac no longer exists --
  1660   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1661 
  1662 * HOL/typedef: fixed type inference for representing set; type
  1663 arguments now have to occur explicitly on the rhs as type constraints;
  1664 
  1665 * ZF: The con_defs part of an inductive definition may no longer refer
  1666 to constants declared in the same theory;
  1667 
  1668 * HOL, ZF: the function mk_cases, generated by the inductive
  1669 definition package, has lost an argument.  To simplify its result, it
  1670 uses the default simpset instead of a supplied list of theorems.
  1671 
  1672 * HOL/List: the constructors of type list are now Nil and Cons;
  1673 
  1674 * Simplifier: the type of the infix ML functions
  1675         setSSolver addSSolver setSolver addSolver
  1676 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1677 for packaging solvers. A solver is created via
  1678         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1679 where the string argument is only a comment.
  1680 
  1681 
  1682 *** Proof tools ***
  1683 
  1684 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1685 decision procedure for linear arithmetic. Currently it is used for
  1686 types `nat', `int', and `real' in HOL (see below); it can, should and
  1687 will be instantiated for other types and logics as well.
  1688 
  1689 * The simplifier now accepts rewrite rules with flexible heads, eg
  1690      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1691   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1692   matching.
  1693 
  1694 
  1695 *** General ***
  1696 
  1697 * New Isabelle/Isar subsystem provides an alternative to traditional
  1698 tactical theorem proving; together with the ProofGeneral/isar user
  1699 interface it offers an interactive environment for developing human
  1700 readable proof documents (Isar == Intelligible semi-automated
  1701 reasoning); for further information see isatool doc isar-ref,
  1702 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1703 
  1704 * improved and simplified presentation of theories: better HTML markup
  1705 (including colors), graph views in several sizes; isatool usedir now
  1706 provides a proper interface for user theories (via -P option); actual
  1707 document preparation based on (PDF)LaTeX is available as well (for
  1708 new-style theories only); see isatool doc system for more information;
  1709 
  1710 * native support for Proof General, both for classic Isabelle and
  1711 Isabelle/Isar;
  1712 
  1713 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1714 using the graph browser tool;
  1715 
  1716 * Isabelle manuals now also available as PDF;
  1717 
  1718 * theory loader rewritten from scratch (may not be fully
  1719 bug-compatible); old loadpath variable has been replaced by show_path,
  1720 add_path, del_path, reset_path functions; new operations such as
  1721 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1722 isatool doc ref);
  1723 
  1724 * improved isatool install: option -k creates KDE application icon,
  1725 option -p DIR installs standalone binaries;
  1726 
  1727 * added ML_PLATFORM setting (useful for cross-platform installations);
  1728 more robust handling of platform specific ML images for SML/NJ;
  1729 
  1730 * the settings environment is now statically scoped, i.e. it is never
  1731 created again in sub-processes invoked from isabelle, isatool, or
  1732 Isabelle;
  1733 
  1734 * path element specification '~~' refers to '$ISABELLE_HOME';
  1735 
  1736 * in locales, the "assumes" and "defines" parts may be omitted if
  1737 empty;
  1738 
  1739 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1740 long arrows);
  1741 
  1742 * new print_mode "HTML";
  1743 
  1744 * new flag show_tags controls display of tags of theorems (which are
  1745 basically just comments that may be attached by some tools);
  1746 
  1747 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1748 mode and goal output format:
  1749 
  1750 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1751 244c244
  1752 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1753 ---
  1754 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1755 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1756 181c181
  1757 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1758 ---
  1759 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1760 
  1761 * function bind_thms stores lists of theorems (cf. bind_thm);
  1762 
  1763 * new shorthand tactics ftac, eatac, datac, fatac;
  1764 
  1765 * qed (and friends) now accept "" as result name; in that case the
  1766 theorem is not stored, but proper checks and presentation of the
  1767 result still apply;
  1768 
  1769 * theorem database now also indexes constants "Trueprop", "all",
  1770 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1771 
  1772 
  1773 *** HOL ***
  1774 
  1775 ** HOL arithmetic **
  1776 
  1777 * There are now decision procedures for linear arithmetic over nat and
  1778 int:
  1779 
  1780 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1781 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1782 are treated as atomic; subformulae not involving type `nat' or `int'
  1783 are ignored; quantified subformulae are ignored unless they are
  1784 positive universal or negative existential. The tactic has to be
  1785 invoked by hand and can be a little bit slow. In particular, the
  1786 running time is exponential in the number of occurrences of `min' and
  1787 `max', and `-' on `nat'.
  1788 
  1789 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1790 (negated) (in)equalities among the premises and the conclusion into
  1791 account (i.e. no compound formulae) and does not know about `min' and
  1792 `max', and `-' on `nat'. It is fast and is used automatically by the
  1793 simplifier.
  1794 
  1795 NB: At the moment, these decision procedures do not cope with mixed
  1796 nat/int formulae where the two parts interact, such as `m < n ==>
  1797 int(m) < int(n)'.
  1798 
  1799 * HOL/Numeral provides a generic theory of numerals (encoded
  1800 efficiently as bit strings); setup for types nat/int/real is in place;
  1801 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1802 int, existing theories and proof scripts may require a few additional
  1803 type constraints;
  1804 
  1805 * integer division and remainder can now be performed on constant
  1806 arguments;
  1807 
  1808 * many properties of integer multiplication, division and remainder
  1809 are now available;
  1810 
  1811 * An interface to the Stanford Validity Checker (SVC) is available through the
  1812 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1813 are proved automatically.  SVC must be installed separately, and its results
  1814 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1815 invocation of the underlying oracle).  For SVC see
  1816   http://verify.stanford.edu/SVC
  1817 
  1818 * IsaMakefile: the HOL-Real target now builds an actual image;
  1819 
  1820 
  1821 ** HOL misc **
  1822 
  1823 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1824 (in Isabelle/Isar) -- by Gertrud Bauer;
  1825 
  1826 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1827 analysis for assembly languages with subtypes;
  1828 
  1829 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1830 -- avoids syntactic ambiguities and treats state, transition, and
  1831 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1832 changed syntax and (many) tactics;
  1833 
  1834 * HOL/inductive: Now also handles more general introduction rules such
  1835   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1836   theorems are now maintained within the theory (maintained via the
  1837   "mono" attribute);
  1838 
  1839 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1840   (using function types) such as
  1841 
  1842   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1843 
  1844 * HOL/record: record_simproc (part of the default simpset) takes care
  1845 of selectors applied to updated records; record_split_tac is no longer
  1846 part of the default claset; update_defs may now be removed from the
  1847 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1848 
  1849   claset_ref () := claset() addSWrapper record_split_wrapper;
  1850   Delsimprocs [record_simproc]
  1851 
  1852 * HOL/typedef: fixed type inference for representing set; type
  1853 arguments now have to occur explicitly on the rhs as type constraints;
  1854 
  1855 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1856 names rather than an ML expression;
  1857 
  1858 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1859 supplied later.  Program schemes can be defined, such as
  1860     "While B C s = (if B s then While B C (C s) else s)"
  1861 where the well-founded relation can be chosen after B and C have been given.
  1862 
  1863 * HOL/List: the constructors of type list are now Nil and Cons;
  1864 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1865 course, ML tools referring to List.list.op # etc. have to be adapted;
  1866 
  1867 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1868 disabled by default; run isabelle with option -m HOL to get back to
  1869 the original Gordon/HOL-style output;
  1870 
  1871 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1872 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1873 
  1874 * HOL basic syntax simplified (more orthogonal): all variants of
  1875 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1876 Eps operator is provided as well: "SOME x. P[x]";
  1877 
  1878 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1879 
  1880 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1881 thus available for user theories;
  1882 
  1883 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1884 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1885 time;
  1886 
  1887 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1888 several times and then mp;
  1889 
  1890 
  1891 *** LK ***
  1892 
  1893 * the notation <<...>> is now available as a notation for sequences of
  1894 formulas;
  1895 
  1896 * the simplifier is now installed
  1897 
  1898 * the axiom system has been generalized (thanks to Soren Heilmann)
  1899 
  1900 * the classical reasoner now has a default rule database
  1901 
  1902 
  1903 *** ZF ***
  1904 
  1905 * new primrec section allows primitive recursive functions to be given
  1906 directly (as in HOL) over datatypes and the natural numbers;
  1907 
  1908 * new tactics induct_tac and exhaust_tac for induction (or case
  1909 analysis) over datatypes and the natural numbers;
  1910 
  1911 * the datatype declaration of type T now defines the recursor T_rec;
  1912 
  1913 * simplification automatically does freeness reasoning for datatype
  1914 constructors;
  1915 
  1916 * automatic type-inference, with AddTCs command to insert new
  1917 type-checking rules;
  1918 
  1919 * datatype introduction rules are now added as Safe Introduction rules
  1920 to the claset;
  1921 
  1922 * the syntax "if P then x else y" is now available in addition to
  1923 if(P,x,y);
  1924 
  1925 
  1926 *** Internal programming interfaces ***
  1927 
  1928 * tuned simplifier trace output; new flag debug_simp;
  1929 
  1930 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1931 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1932 
  1933 * AxClass.axclass_tac lost the theory argument;
  1934 
  1935 * tuned current_goals_markers semantics: begin / end goal avoids
  1936 printing empty lines;
  1937 
  1938 * removed prs and prs_fn hook, which was broken because it did not
  1939 include \n in its semantics, forcing writeln to add one
  1940 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1941 string -> unit if you really want to output text without newline;
  1942 
  1943 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1944 plain output, interface builders may have to enable 'isabelle_font'
  1945 mode to get Isabelle font glyphs as before;
  1946 
  1947 * refined token_translation interface; INCOMPATIBILITY: output length
  1948 now of type real instead of int;
  1949 
  1950 * theory loader actions may be traced via new ThyInfo.add_hook
  1951 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1952 your own database of information attached to *whole* theories -- as
  1953 opposed to intra-theory data slots offered via TheoryDataFun;
  1954 
  1955 * proper handling of dangling sort hypotheses (at last!);
  1956 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1957 extra sort hypotheses that can be witnessed from the type signature;
  1958 the force_strip_shyps flag is gone, any remaining shyps are simply
  1959 left in the theorem (with a warning issued by strip_shyps_warning);
  1960 
  1961 
  1962 
  1963 New in Isabelle98-1 (October 1998)
  1964 ----------------------------------
  1965 
  1966 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1967 
  1968 * several changes of automated proof tools;
  1969 
  1970 * HOL: major changes to the inductive and datatype packages, including
  1971 some minor incompatibilities of theory syntax;
  1972 
  1973 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1974 called `inj_on';
  1975 
  1976 * HOL: removed duplicate thms in Arith:
  1977   less_imp_add_less  should be replaced by  trans_less_add1
  1978   le_imp_add_le      should be replaced by  trans_le_add1
  1979 
  1980 * HOL: unary minus is now overloaded (new type constraints may be
  1981 required);
  1982 
  1983 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1984 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1985 now taken as an integer constant.
  1986 
  1987 * Pure: ML function 'theory_of' renamed to 'theory';
  1988 
  1989 
  1990 *** Proof tools ***
  1991 
  1992 * Simplifier:
  1993   1. Asm_full_simp_tac is now more aggressive.
  1994      1. It will sometimes reorient premises if that increases their power to
  1995         simplify.
  1996      2. It does no longer proceed strictly from left to right but may also
  1997         rotate premises to achieve further simplification.
  1998      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1999      old Asm_full_simp_tac in that it does not rotate premises.
  2000   2. The simplifier now knows a little bit about nat-arithmetic.
  2001 
  2002 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2003 allows for selected deletion of wrappers, by introduction of names for
  2004 wrapper functionals.  This implies that addbefore, addSbefore,
  2005 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2006 and that adding two tactics with the same name overwrites the first
  2007 one (emitting a warning).
  2008   type wrapper = (int -> tactic) -> (int -> tactic)
  2009   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2010   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2011   delWrapper, delSWrapper: claset *  string            -> claset
  2012   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2013 
  2014 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2015 semantics; addbefore now affects only the unsafe part of step_tac
  2016 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2017 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2018 by Force_tac;
  2019 
  2020 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2021 compWrapper; added safe wrapper (and access functions for it);
  2022 
  2023 * HOL/split_all_tac is now much faster and fails if there is nothing
  2024 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2025 and the names of the automatically generated variables have changed.
  2026 split_all_tac has moved within claset() from unsafe wrappers to safe
  2027 wrappers, which means that !!-bound variables are split much more
  2028 aggressively, and safe_tac and clarify_tac now split such variables.
  2029 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2030 Note: the same holds for record_split_tac, which does the job of
  2031 split_all_tac for record fields.
  2032 
  2033 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2034 permanently to the default simpset using Addsplits just like
  2035 Addsimps. They can be removed via Delsplits just like
  2036 Delsimps. Lower-case versions are also available.
  2037 
  2038 * HOL/Simplifier: The rule split_if is now part of the default
  2039 simpset. This means that the simplifier will eliminate all occurrences
  2040 of if-then-else in the conclusion of a goal. To prevent this, you can
  2041 either remove split_if completely from the default simpset by
  2042 `Delsplits [split_if]' or remove it in a specific call of the
  2043 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2044 other case splitting rules to/from the default simpset: every datatype
  2045 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2046 t is the name of the datatype).
  2047 
  2048 * Classical reasoner / Simplifier combination: new force_tac (and
  2049 derivatives Force_tac, force) combines rewriting and classical
  2050 reasoning (and whatever other tools) similarly to auto_tac, but is
  2051 aimed to solve the given subgoal completely.
  2052 
  2053 
  2054 *** General ***
  2055 
  2056 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2057 and `goalw': the theory is no longer needed as an explicit argument -
  2058 the current theory context is used; assumptions are no longer returned
  2059 at the ML-level unless one of them starts with ==> or !!; it is
  2060 recommended to convert to these new commands using isatool fixgoal
  2061 (backup your sources first!);
  2062 
  2063 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2064 the current theory context, and 'theory' to lookup stored theories;
  2065 
  2066 * new theory section 'locale' for declaring constants, assumptions and
  2067 definitions that have local scope;
  2068 
  2069 * new theory section 'nonterminals' for purely syntactic types;
  2070 
  2071 * new theory section 'setup' for generic ML setup functions
  2072 (e.g. package initialization);
  2073 
  2074 * the distribution now includes Isabelle icons: see
  2075 lib/logo/isabelle-{small,tiny}.xpm;
  2076 
  2077 * isatool install - install binaries with absolute references to
  2078 ISABELLE_HOME/bin;
  2079 
  2080 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2081 
  2082 * print mode 'emacs' reserved for Isamode;
  2083 
  2084 * support multiple print (ast) translations per constant name;
  2085 
  2086 * theorems involving oracles are now printed with a suffixed [!];
  2087 
  2088 
  2089 *** HOL ***
  2090 
  2091 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2092 
  2093 * HOL/inductive package reorganized and improved: now supports mutual
  2094 definitions such as
  2095 
  2096   inductive EVEN ODD
  2097     intrs
  2098       null "0 : EVEN"
  2099       oddI "n : EVEN ==> Suc n : ODD"
  2100       evenI "n : ODD ==> Suc n : EVEN"
  2101 
  2102 new theorem list "elims" contains an elimination rule for each of the
  2103 recursive sets; inductive definitions now handle disjunctive premises
  2104 correctly (also ZF);
  2105 
  2106 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2107 "mutual_induct" no longer exists - the induction rule is always
  2108 contained in "induct";
  2109 
  2110 
  2111 * HOL/datatype package re-implemented and greatly improved: now
  2112 supports mutually recursive datatypes such as
  2113 
  2114   datatype
  2115     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2116             | SUM ('a aexp) ('a aexp)
  2117             | DIFF ('a aexp) ('a aexp)
  2118             | NUM 'a
  2119   and
  2120     'a bexp = LESS ('a aexp) ('a aexp)
  2121             | AND ('a bexp) ('a bexp)
  2122             | OR ('a bexp) ('a bexp)
  2123 
  2124 as well as indirectly recursive datatypes such as
  2125 
  2126   datatype
  2127     ('a, 'b) term = Var 'a
  2128                   | App 'b ((('a, 'b) term) list)
  2129 
  2130 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2131 induction on mutually / indirectly recursive datatypes.
  2132 
  2133 Primrec equations are now stored in theory and can be accessed via
  2134 <function_name>.simps.
  2135 
  2136 INCOMPATIBILITIES:
  2137 
  2138   - Theories using datatypes must now have theory Datatype as an
  2139     ancestor.
  2140   - The specific <typename>.induct_tac no longer exists - use the
  2141     generic induct_tac instead.
  2142   - natE has been renamed to nat.exhaust - use exhaust_tac
  2143     instead of res_inst_tac ... natE. Note that the variable
  2144     names in nat.exhaust differ from the names in natE, this
  2145     may cause some "fragile" proofs to fail.
  2146   - The theorems split_<typename>_case and split_<typename>_case_asm
  2147     have been renamed to <typename>.split and <typename>.split_asm.
  2148   - Since default sorts of type variables are now handled correctly,
  2149     some datatype definitions may have to be annotated with explicit
  2150     sort constraints.
  2151   - Primrec definitions no longer require function name and type
  2152     of recursive argument.
  2153 
  2154 Consider using isatool fixdatatype to adapt your theories and proof
  2155 scripts to the new package (backup your sources first!).
  2156 
  2157 
  2158 * HOL/record package: considerably improved implementation; now
  2159 includes concrete syntax for record types, terms, updates; theorems
  2160 for surjective pairing and splitting !!-bound record variables; proof
  2161 support is as follows:
  2162 
  2163   1) standard conversions (selectors or updates applied to record
  2164 constructor terms) are part of the standard simpset;
  2165 
  2166   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2167 made part of standard simpset and claset via addIffs;
  2168 
  2169   3) a tactic for record field splitting (record_split_tac) is part of
  2170 the standard claset (addSWrapper);
  2171 
  2172 To get a better idea about these rules you may retrieve them via
  2173 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2174 the name of your record type.
  2175 
  2176 The split tactic 3) conceptually simplifies by the following rule:
  2177 
  2178   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2179 
  2180 Thus any record variable that is bound by meta-all will automatically
  2181 blow up into some record constructor term, consequently the
  2182 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2183 solve record problems automatically.
  2184 
  2185 
  2186 * reorganized the main HOL image: HOL/Integ and String loaded by
  2187 default; theory Main includes everything;
  2188 
  2189 * automatic simplification of integer sums and comparisons, using cancellation;
  2190 
  2191 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2192 
  2193 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2194 
  2195 * many new identities for unions, intersections, set difference, etc.;
  2196 
  2197 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2198 called split_if, split_split, split_sum_case and split_nat_case (to go
  2199 with add/delsplits);
  2200 
  2201 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2202 (?x::unit) = (); this is made part of the default simpset, which COULD
  2203 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2204 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2205 unit_abs_eta_conv is added in order to counter the effect of
  2206 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2207 %u.f();
  2208 
  2209 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2210 makes more sense);
  2211 
  2212 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2213   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2214   disjointness reasoning but breaking a few old proofs.
  2215 
  2216 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2217 to 'converse' from 'inverse' (for compatibility with ZF and some
  2218 literature);
  2219 
  2220 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2221 the well-founded relation;
  2222 
  2223 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2224     Compl A.  The "Compl" syntax remains available as input syntax for this
  2225     release ONLY.
  2226 
  2227 * HOL/Update: new theory of function updates:
  2228     f(a:=b) == %x. if x=a then b else f x
  2229 may also be iterated as in f(a:=b,c:=d,...);
  2230 
  2231 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2232 
  2233 * HOL/List:
  2234   - new function list_update written xs[i:=v] that updates the i-th
  2235     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2236   - new function `upt' written [i..j(] which generates the list
  2237     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2238     bound write [i..j], which is a shorthand for [i..j+1(].
  2239   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2240 
  2241 * HOL/Arith:
  2242   - removed 'pred' (predecessor) function;
  2243   - generalized some theorems about n-1;
  2244   - many new laws about "div" and "mod";
  2245   - new laws about greatest common divisors (see theory ex/Primes);
  2246 
  2247 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2248 instead of "inverse";
  2249 
  2250 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2251   of the multiset ordering;
  2252 
  2253 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2254   (not included by default);
  2255 
  2256 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2257 
  2258 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2259   programs, i.e. different program variables may have different types.
  2260 
  2261 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2262   [previously, this check worked only if the rewrite rule was unconditional]
  2263   Now rew can involve either definitions or equalities (either == or =).
  2264 
  2265 
  2266 *** ZF ***
  2267 
  2268 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2269   only the theorems proved on ZF.ML;
  2270 
  2271 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2272   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2273   disjointness reasoning but breaking a few old proofs.
  2274 
  2275 * ZF/Update: new theory of function updates
  2276     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2277   may also be iterated as in f(a:=b,c:=d,...);
  2278 
  2279 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2280 
  2281 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2282   [previously, this check worked only if the rewrite rule was unconditional]
  2283   Now rew can involve either definitions or equalities (either == or =).
  2284 
  2285 * case_tac provided for compatibility with HOL
  2286     (like the old excluded_middle_tac, but with subgoals swapped)
  2287 
  2288 
  2289 *** Internal programming interfaces ***
  2290 
  2291 * Pure: several new basic modules made available for general use, see
  2292 also src/Pure/README;
  2293 
  2294 * improved the theory data mechanism to support encapsulation (data
  2295 kind name replaced by private Object.kind, acting as authorization
  2296 key); new type-safe user interface via functor TheoryDataFun; generic
  2297 print_data function becomes basically useless;
  2298 
  2299 * removed global_names compatibility flag -- all theory declarations
  2300 are qualified by default;
  2301 
  2302 * module Pure/Syntax now offers quote / antiquote translation
  2303 functions (useful for Hoare logic etc. with implicit dependencies);
  2304 see HOL/ex/Antiquote for an example use;
  2305 
  2306 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2307 cterm -> thm;
  2308 
  2309 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2310 subgoal;
  2311 
  2312 * Display.print_goals function moved to Locale.print_goals;
  2313 
  2314 * standard print function for goals supports current_goals_markers
  2315 variable for marking begin of proof, end of proof, start of goal; the
  2316 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2317 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2318 for example;
  2319 
  2320 
  2321 
  2322 New in Isabelle98 (January 1998)
  2323 --------------------------------
  2324 
  2325 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2326 
  2327 * changed lexical syntax of terms / types: dots made part of long
  2328 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2329 
  2330 * simpset (and claset) reference variable replaced by functions
  2331 simpset / simpset_ref;
  2332 
  2333 * no longer supports theory aliases (via merge) and non-trivial
  2334 implicit merge of thms' signatures;
  2335 
  2336 * most internal names of constants changed due to qualified names;
  2337 
  2338 * changed Pure/Sequence interface (see Pure/seq.ML);
  2339 
  2340 
  2341 *** General Changes ***
  2342 
  2343 * hierachically structured name spaces (for consts, types, axms, thms
  2344 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2345 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2346 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2347 long_names for fully qualified output names; NOTE: ML programs
  2348 (special tactics, packages etc.) referring to internal names may have
  2349 to be adapted to cope with fully qualified names; in case of severe
  2350 backward campatibility problems try setting 'global_names' at compile
  2351 time to have enrything declared within a flat name space; one may also
  2352 fine tune name declarations in theories via the 'global' and 'local'
  2353 section;
  2354 
  2355 * reimplemented the implicit simpset and claset using the new anytype
  2356 data filed in signatures; references simpset:simpset ref etc. are
  2357 replaced by functions simpset:unit->simpset and
  2358 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2359 to patch your ML files accordingly;
  2360 
  2361 * HTML output now includes theory graph data for display with Java
  2362 applet or isatool browser; data generated automatically via isatool
  2363 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2364 
  2365 * defs may now be conditional; improved rewrite_goals_tac to handle
  2366 conditional equations;
  2367 
  2368 * defs now admits additional type arguments, using TYPE('a) syntax;
  2369 
  2370 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2371 creates a new theory node; implicit merge of thms' signatures is
  2372 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2373 transfer:theory->thm->thm in (rare) cases;
  2374 
  2375 * improved handling of draft signatures / theories; draft thms (and
  2376 ctyps, cterms) are automatically promoted to real ones;
  2377 
  2378 * slightly changed interfaces for oracles: admit many per theory, named
  2379 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2380 
  2381 * print_goals: optional output of const types (set show_consts and
  2382 show_types);
  2383 
  2384 * improved output of warnings (###) and errors (***);
  2385 
  2386 * subgoal_tac displays a warning if the new subgoal has type variables;
  2387 
  2388 * removed old README and Makefiles;
  2389 
  2390 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2391 
  2392 * removed obsolete init_pps and init_database;
  2393 
  2394 * deleted the obsolete tactical STATE, which was declared by
  2395     fun STATE tacfun st = tacfun st st;
  2396 
  2397 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2398 (which abbreviates $HOME);
  2399 
  2400 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2401 use isatool fixseq to adapt your ML programs (this works for fully
  2402 qualified references to the Sequence structure only!);
  2403 
  2404 * use_thy no longer requires writable current directory; it always
  2405 reloads .ML *and* .thy file, if either one is out of date;
  2406 
  2407 
  2408 *** Classical Reasoner ***
  2409 
  2410 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2411 tactics that use classical reasoning to simplify a subgoal without
  2412 splitting it into several subgoals;
  2413 
  2414 * Safe_tac: like safe_tac but uses the default claset;
  2415 
  2416 
  2417 *** Simplifier ***
  2418 
  2419 * added simplification meta rules:
  2420     (asm_)(full_)simplify: simpset -> thm -> thm;
  2421 
  2422 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2423 logics (again);
  2424 
  2425 * added prems argument to simplification procedures;
  2426 
  2427 * HOL, FOL, ZF: added infix function `addsplits':
  2428   instead of `<simpset> setloop (split_tac <thms>)'
  2429   you can simply write `<simpset> addsplits <thms>'
  2430 
  2431 
  2432 *** Syntax ***
  2433 
  2434 * TYPE('a) syntax for type reflection terms;
  2435 
  2436 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2437 
  2438 * pretty printer: changed order of mixfix annotation preference (again!);
  2439 
  2440 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2441 
  2442 
  2443 *** HOL ***
  2444 
  2445 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2446   with `addloop' of the simplifier to faciliate case splitting in premises.
  2447 
  2448 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2449 
  2450 * HOL/Auth: new protocol proofs including some for the Internet
  2451   protocol TLS;
  2452 
  2453 * HOL/Map: new theory of `maps' a la VDM;
  2454 
  2455 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2456 cancelling out common nat summands from =, <, <= (in)equalities, or
  2457 differences; simplification procedures nat_cancel_factor for
  2458 cancelling common factor from =, <, <= (in)equalities over natural
  2459 sums; nat_cancel contains both kinds of procedures, it is installed by
  2460 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2461 
  2462 * HOL/simplifier: terms of the form
  2463   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2464   are rewritten to
  2465   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2466   and those of the form
  2467   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2468   are rewritten to
  2469   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2470 
  2471 * HOL/datatype
  2472   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2473 
  2474   P(t_case f1 ... fn x) =
  2475      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2476         ...
  2477        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2478      )
  2479 
  2480   and a theorem `split_t_case_asm' of the form
  2481 
  2482   P(t_case f1 ... fn x) =
  2483     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2484         ...
  2485        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2486      )
  2487   which can be added to a simpset via `addsplits'. The existing theorems
  2488   expand_list_case and expand_option_case have been renamed to
  2489   split_list_case and split_option_case.
  2490 
  2491 * HOL/Arithmetic:
  2492   - `pred n' is automatically converted to `n-1'.
  2493     Users are strongly encouraged not to use `pred' any longer,
  2494     because it will disappear altogether at some point.
  2495   - Users are strongly encouraged to write "0 < n" rather than
  2496     "n ~= 0". Theorems and proof tools have been modified towards this
  2497     `standard'.
  2498 
  2499 * HOL/Lists:
  2500   the function "set_of_list" has been renamed "set" (and its theorems too);
  2501   the function "nth" now takes its arguments in the reverse order and
  2502   has acquired the infix notation "!" as in "xs!n".
  2503 
  2504 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2505 
  2506 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2507   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2508 
  2509 * HOL/record: extensible records with schematic structural subtyping
  2510 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2511 still lacks various theorems and concrete record syntax;
  2512 
  2513 
  2514 *** HOLCF ***
  2515 
  2516 * removed "axioms" and "generated by" sections;
  2517 
  2518 * replaced "ops" section by extended "consts" section, which is capable of
  2519   handling the continuous function space "->" directly;
  2520 
  2521 * domain package:
  2522   . proves theorems immediately and stores them in the theory,
  2523   . creates hierachical name space,
  2524   . now uses normal mixfix annotations (instead of cinfix...),
  2525   . minor changes to some names and values (for consistency),
  2526   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2527   . separator between mutual domain defs: changed "," to "and",
  2528   . improved handling of sort constraints;  now they have to
  2529     appear on the left-hand side of the equations only;
  2530 
  2531 * fixed LAM <x,y,zs>.b syntax;
  2532 
  2533 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2534 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2535 
  2536 
  2537 *** FOL and ZF ***
  2538 
  2539 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2540   with `addloop' of the simplifier to faciliate case splitting in premises.
  2541 
  2542 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2543 in HOL, they strip ALL and --> from proved theorems;
  2544 
  2545 
  2546 
  2547 New in Isabelle94-8 (May 1997)
  2548 ------------------------------
  2549 
  2550 *** General Changes ***
  2551 
  2552 * new utilities to build / run / maintain Isabelle etc. (in parts
  2553 still somewhat experimental); old Makefiles etc. still functional;
  2554 
  2555 * new 'Isabelle System Manual';
  2556 
  2557 * INSTALL text, together with ./configure and ./build scripts;
  2558 
  2559 * reimplemented type inference for greater efficiency, better error
  2560 messages and clean internal interface;
  2561 
  2562 * prlim command for dealing with lots of subgoals (an easier way of
  2563 setting goals_limit);
  2564 
  2565 
  2566 *** Syntax ***
  2567 
  2568 * supports alternative (named) syntax tables (parser and pretty
  2569 printer); internal interface is provided by add_modesyntax(_i);
  2570 
  2571 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2572 be used in conjunction with the Isabelle symbol font; uses the
  2573 "symbols" syntax table;
  2574 
  2575 * added token_translation interface (may translate name tokens in
  2576 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2577 the current print_mode); IMPORTANT: user print translation functions
  2578 are responsible for marking newly introduced bounds
  2579 (Syntax.mark_boundT);
  2580 
  2581 * token translations for modes "xterm" and "xterm_color" that display
  2582 names in bold, underline etc. or colors (which requires a color
  2583 version of xterm);
  2584 
  2585 * infixes may now be declared with names independent of their syntax;
  2586 
  2587 * added typed_print_translation (like print_translation, but may
  2588 access type of constant);
  2589 
  2590 
  2591 *** Classical Reasoner ***
  2592 
  2593 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2594 some limitations.  Blast_tac...
  2595   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2596   + ignores elimination rules that don't have the correct format
  2597         (the conclusion MUST be a formula variable)
  2598   + ignores types, which can make HOL proofs fail
  2599   + rules must not require higher-order unification, e.g. apply_type in ZF
  2600     [message "Function Var's argument not a bound variable" relates to this]
  2601   + its proof strategy is more general but can actually be slower
  2602 
  2603 * substitution with equality assumptions no longer permutes other
  2604 assumptions;
  2605 
  2606 * minor changes in semantics of addafter (now called addaltern); renamed
  2607 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2608 (and access functions for it);
  2609 
  2610 * improved combination of classical reasoner and simplifier:
  2611   + functions for handling clasimpsets
  2612   + improvement of addss: now the simplifier is called _after_ the
  2613     safe steps.
  2614   + safe variant of addss called addSss: uses safe simplifications
  2615     _during_ the safe steps. It is more complete as it allows multiple
  2616     instantiations of unknowns (e.g. with slow_tac).
  2617 
  2618 *** Simplifier ***
  2619 
  2620 * added interface for simplification procedures (functions that
  2621 produce *proven* rewrite rules on the fly, depending on current
  2622 redex);
  2623 
  2624 * ordering on terms as parameter (used for ordered rewriting);
  2625 
  2626 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2627 
  2628 * the solver is now split into a safe and an unsafe part.
  2629 This should be invisible for the normal user, except that the
  2630 functions setsolver and addsolver have been renamed to setSolver and
  2631 addSolver; added safe_asm_full_simp_tac;
  2632 
  2633 
  2634 *** HOL ***
  2635 
  2636 * a generic induction tactic `induct_tac' which works for all datatypes and
  2637 also for type `nat';
  2638 
  2639 * a generic case distinction tactic `exhaust_tac' which works for all
  2640 datatypes and also for type `nat';
  2641 
  2642 * each datatype comes with a function `size';
  2643 
  2644 * patterns in case expressions allow tuple patterns as arguments to
  2645 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2646 
  2647 * primrec now also works with type nat;
  2648 
  2649 * recdef: a new declaration form, allows general recursive functions to be
  2650 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2651 
  2652 * the constant for negation has been renamed from "not" to "Not" to
  2653 harmonize with FOL, ZF, LK, etc.;
  2654 
  2655 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2656 infinite lists;
  2657 
  2658 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2659 
  2660 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2661 problems in commutative rings, using axiomatic type classes for + and *;
  2662 
  2663 * more examples in HOL/MiniML and HOL/Auth;
  2664 
  2665 * more default rewrite rules for quantifiers, union/intersection;
  2666 
  2667 * a new constant `arbitrary == @x.False';
  2668 
  2669 * HOLCF/IOA replaces old HOL/IOA;
  2670 
  2671 * HOLCF changes: derived all rules and arities
  2672   + axiomatic type classes instead of classes
  2673   + typedef instead of faking type definitions
  2674   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2675   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2676   + eliminated the types void, one, tr
  2677   + use unit lift and bool lift (with translations) instead of one and tr
  2678   + eliminated blift from Lift3.thy (use Def instead of blift)
  2679   all eliminated rules are derived as theorems --> no visible changes ;
  2680 
  2681 
  2682 *** ZF ***
  2683 
  2684 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2685 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2686 as ZF_cs addSIs [equalityI];
  2687 
  2688 
  2689 
  2690 New in Isabelle94-7 (November 96)
  2691 ---------------------------------
  2692 
  2693 * allowing negative levels (as offsets) in prlev and choplev;
  2694 
  2695 * super-linear speedup for large simplifications;
  2696 
  2697 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2698 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2699 FAIL); can suppress it using the command Delsimps (ex_simps @
  2700 all_simps); De Morgan laws are also now included, by default;
  2701 
  2702 * improved printing of ==>  :  ~:
  2703 
  2704 * new object-logic "Sequents" adds linear logic, while replacing LK
  2705 and Modal (thanks to Sara Kalvala);
  2706 
  2707 * HOL/Auth: correctness proofs for authentication protocols;
  2708 
  2709 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2710 examples on HOL/Auth);
  2711 
  2712 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2713 the rewriter and classical reasoner simultaneously;
  2714 
  2715 * function uresult no longer returns theorems in "standard" format;
  2716 regain previous version by: val uresult = standard o uresult;
  2717 
  2718 
  2719 
  2720 New in Isabelle94-6
  2721 -------------------
  2722 
  2723 * oracles -- these establish an interface between Isabelle and trusted
  2724 external reasoners, which may deliver results as theorems;
  2725 
  2726 * proof objects (in particular record all uses of oracles);
  2727 
  2728 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2729 
  2730 * "constdefs" section in theory files;
  2731 
  2732 * "primrec" section (HOL) no longer requires names;
  2733 
  2734 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2735 
  2736 
  2737 
  2738 New in Isabelle94-5
  2739 -------------------
  2740 
  2741 * reduced space requirements;
  2742 
  2743 * automatic HTML generation from theories;
  2744 
  2745 * theory files no longer require "..." (quotes) around most types;
  2746 
  2747 * new examples, including two proofs of the Church-Rosser theorem;
  2748 
  2749 * non-curried (1994) version of HOL is no longer distributed;
  2750 
  2751 
  2752 
  2753 New in Isabelle94-4
  2754 -------------------
  2755 
  2756 * greatly reduced space requirements;
  2757 
  2758 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2759 
  2760 * searchable theorem database (see the section "Retrieving theorems" on
  2761 page 8 of the Reference Manual);
  2762 
  2763 * new examples, including Grabczewski's monumental case study of the
  2764 Axiom of Choice;
  2765 
  2766 * The previous version of HOL renamed to Old_HOL;
  2767 
  2768 * The new version of HOL (previously called CHOL) uses a curried syntax
  2769 for functions.  Application looks like f a b instead of f(a,b);
  2770 
  2771 * Mutually recursive inductive definitions finally work in HOL;
  2772 
  2773 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2774 translates to the operator "split";
  2775 
  2776 
  2777 
  2778 New in Isabelle94-3
  2779 -------------------
  2780 
  2781 * new infix operator, addss, allowing the classical reasoner to
  2782 perform simplification at each step of its search.  Example:
  2783         fast_tac (cs addss ss)
  2784 
  2785 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2786 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2787 look like (a,b) instead of <a,b>;
  2788 
  2789 * PLEASE NOTE: CHOL will eventually replace HOL!
  2790 
  2791 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2792 It translates to the operator "split".  A new theory of integers is available;
  2793 
  2794 * In ZF, integer numerals now denote two's-complement binary integers.
  2795 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2796 
  2797 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2798 of the Axiom of Choice;
  2799 
  2800 
  2801 
  2802 New in Isabelle94-2
  2803 -------------------
  2804 
  2805 * Significantly faster resolution;
  2806 
  2807 * the different sections in a .thy file can now be mixed and repeated
  2808 freely;
  2809 
  2810 * Database of theorems for FOL, HOL and ZF.  New
  2811 commands including qed, qed_goal and bind_thm store theorems in the database.
  2812 
  2813 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2814 a given theory (thms_of), or find out what theory a theorem was proved in
  2815 (theory_of_thm);
  2816 
  2817 * Bugs fixed in the inductive definition and datatype packages;
  2818 
  2819 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2820 and HOL_dup_cs obsolete;
  2821 
  2822 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2823 have been removed;
  2824 
  2825 * Simpler definition of function space in ZF;
  2826 
  2827 * new results about cardinal and ordinal arithmetic in ZF;
  2828 
  2829 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2830 types;
  2831 
  2832 
  2833 $Id$