NEWS
author webertj
Mon Aug 23 16:41:06 2004 +0200 (2004-08-23)
changeset 15154 db582d6e89de
parent 15148 3879dc0e9a9c
child 15163 73386e0319a2
permissions -rw-r--r--
new isatool dimacs2hol
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Theory headers: the new header syntax for Isar theories is
    10 
    11   theory <name>
    12   imports <theory1> ... <theoryn>
    13   begin
    14 
    15   optionally also with a "files" section. The syntax
    16 
    17   theory <name> = <theory1> + ... + <theoryn>:
    18 
    19   will still be supported for some time but will eventually disappear.
    20   The syntax of old-style theories has not changed.
    21 
    22 * Provers/quasi.ML:  new transitivity reasoners for transitivity only
    23   and quasi orders.
    24 
    25 * Provers/trancl.ML:  new transitivity reasoner for transitive and
    26   reflexive-transitive closure of relations.
    27 
    28 * Pure: considerably improved version of 'constdefs' command.  Now
    29   performs automatic type-inference of declared constants; additional
    30   support for local structure declarations (cf. locales and HOL
    31   records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    32   to observe strictly sequential dependencies of definitions within a
    33   single 'constdefs' section; moreover, the declared name needs to be
    34   an identifier.  If all fails, consider to fall back on 'consts' and
    35   'defs' separately.
    36 
    37 * Pure: improved indexed syntax and implicit structures.  First of
    38   all, indexed syntax provides a notational device for subscripted
    39   application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    40   expressions.  Secondly, in a local context with structure
    41   declarations, number indexes \<^sub>n or the empty index (default
    42   number 1) refer to a certain fixed variable implicitly; option
    43   show_structs controls printing of implicit structures.  Typical
    44   applications of these concepts involve record types and locales.
    45 
    46 * Pure: clear separation of logical types and nonterminals, where the
    47   latter may only occur in 'syntax' specifications or type
    48   abbreviations.  Before that distinction was only partially
    49   implemented via type class "logic" vs. "{}".  Potential
    50   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
    51   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
    52   specifications may require further adaption (e.g. Cube/Base.thy).
    53 
    54 * Pure: removed obsolete type class "logic", use the top sort {}
    55   instead.  Note that non-logical types should be declared as
    56   'nonterminals' rather than 'types'.  INCOMPATIBILITY for new
    57   object-logic specifications.
    58 
    59 * Pure: print_tac now outputs the goal through the trace channel.
    60 
    61 * Pure: reference Namespace.unique_names included.  If true the
    62   (shortest) namespace-prefix is printed to disambiguate conflicts (as
    63   yet). If false the first entry wins (as during parsing). Default
    64   value is true.
    65 
    66 * Pure: tuned internal renaming of symbolic identifiers -- attach
    67   primes instead of base 26 numbers.
    68 
    69 * Pure/Syntax: inner syntax includes (*(*nested*) comments*).
    70 
    71 * Pure/Syntax: pretty pinter now supports unbreakable blocks,
    72   specified in mixfix annotations as "(00...)".
    73 
    74 * Pure/Syntax: 'advanced' translation functions (parse_translation
    75   etc.) may depend on the signature of the theory context being
    76   presently used for parsing/printing, see also isar-ref manual.
    77 
    78 * Pure/Simplifier: simplification procedures may now take the current
    79   simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
    80   interface), which is very useful for calling the Simplifier
    81   recursively.  Minor INCOMPATIBILITY: the 'prems' argument of
    82   simprocs is gone -- use prems_of_ss on the simpset instead.
    83   Moreover, the low-level mk_simproc no longer applies Logic.varify
    84   internally, to allow for use in a context of fixed variables.
    85 
    86 * Provers: Simplifier and Classical Reasoner now support proof context
    87   dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
    88   components are stored in the theory and patched into the
    89   simpset/claset when used in an Isar proof context.  Context
    90   dependent components are maintained by the following theory
    91   operations:
    92 
    93     Simplifier.add_context_simprocs
    94     Simplifier.del_context_simprocs
    95     Simplifier.set_context_subgoaler
    96     Simplifier.reset_context_subgoaler
    97     Simplifier.add_context_looper
    98     Simplifier.del_context_looper
    99     Simplifier.add_context_unsafe_solver
   100     Simplifier.add_context_safe_solver
   101 
   102     Classical.add_context_safe_wrapper
   103     Classical.del_context_safe_wrapper
   104     Classical.add_context_unsafe_wrapper
   105     Classical.del_context_unsafe_wrapper
   106 
   107   IMPORTANT NOTE: proof tools (methods etc.) need to use
   108   local_simpset_of and local_claset_of to instead of the primitive
   109   Simplifier.get_local_simpset and Classical.get_local_claset,
   110   respectively, in order to see the context dependent fields!
   111 
   112 * Document preparation: antiquotations now provide the option
   113   'locale=NAME' to specify an alternative context used for evaluating
   114   and printing the subsequent argument, as in @{thm [locale=LC]
   115   fold_commute}, for example.
   116 
   117 * Document preparation: commands 'display_drafts' and 'print_drafts'
   118   perform simple output of raw sources.  Only those symbols that do
   119   not require additional LaTeX packages (depending on comments in
   120   isabellesym.sty) are displayed properly, everything else is left
   121   verbatim.  We use isatool display and isatool print as front ends;
   122   these are subject to the DVI_VIEWER and PRINT_COMMAND settings,
   123   respectively.
   124 
   125 * ML: output via the Isabelle channels of writeln/warning/error
   126   etc. is now passed through Output.output, with a hook for arbitrary
   127   transformations depending on the print_mode (cf. Output.add_mode --
   128   the first active mode that provides a output function wins).
   129   Already formatted output may be embedded into further text via
   130   Output.raw; the result of Pretty.string_of/str_of and derived
   131   functions (string_of_term/cterm/thm etc.) is already marked raw to
   132   accommodate easy composition of diagnostic messages etc.
   133   Programmers rarely need to care about Output.output or Output.raw at
   134   all, with some notable exceptions: Output.output is required when
   135   bypassing the standard channels (writeln etc.), or in token
   136   translations to produce properly formatted results; Output.raw is
   137   required when capturing already output material that will eventually
   138   be presented to the user a second time.  For the default print mode,
   139   both Output.output and Output.raw have no effect.
   140 
   141 
   142 *** Isar ***
   143 
   144 * Locales:
   145   - "includes" disallowed in declaration of named locales (command "locale").
   146 
   147  
   148 *** HOL ***
   149 
   150 * HOL/record: reimplementation of records. Improved scalability for
   151   records with many fields, avoiding performance problems for type
   152   inference. Records are no longer composed of nested field types, but
   153   of nested extension types. Therefore the record type only grows
   154   linear in the number of extensions and not in the number of fields.
   155   The top-level (users) view on records is preserved.  Potential
   156   INCOMPATIBILITY only in strange cases, where the theory depends on
   157   the old record representation. The type generated for a record is
   158   called <record_name>_ext_type.
   159 
   160 * HOL/record: Reference record_quick_and_dirty_sensitive can be
   161   enabled to skip the proofs triggered by a record definition or a
   162   simproc (if quick_and_dirty is enabled). Definitions of large
   163   records can take quite long.
   164 
   165 * HOL/record: "record_upd_simproc" for simplification of multiple
   166   record updates enabled by default.  Moreover, trivial updates are
   167   also removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   168   occasionally, since simplification is more powerful by default.
   169 
   170 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
   171 
   172   syntax (epsilon)
   173     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   174 
   175   The symbol \<some> is displayed as the alternative epsilon of LaTeX
   176   and x-symbol; use option '-m epsilon' to get it actually printed.
   177   Moreover, the mathematically important symbolic identifier
   178   \<epsilon> becomes available as variable, constant etc.
   179 
   180 * HOL/SetInterval: The syntax for open intervals has changed:
   181 
   182   Old         New
   183   {..n(}   -> {..<n}
   184   {)n..}   -> {n<..}
   185   {m..n(}  -> {m..<n}
   186   {)m..n}  -> {m<..n}
   187   {)m..n(} -> {m<..<n}
   188 
   189   The old syntax is still supported but will disappear in the future.
   190   For conversion use the following emacs search and replace patterns:
   191 
   192   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   193   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   194 
   195   They are not perfect but work quite well.
   196 
   197 * HOL: The syntax for 'setsum', summation over finite sets, has changed:
   198 
   199   The syntax for 'setsum (%x. e) A' used to be '\<Sum>x:A. e'
   200   and is now either 'SUM x:A. e' or '\<Sum>x\<in>A. e'.
   201 
   202   There is new syntax for summation over finite sets:
   203 
   204   '\<Sum>x | P. e'    is the same as  'setsum (%x. e) {x. P}'
   205   '\<Sum>x=a..b. e'   is the same as  'setsum (%x. e) {a..b}'
   206   '\<Sum>x=a..<b. e'  is the same as  'setsum (%x. e) {a..<b}'
   207   '\<Sum>x<k. e'      is the same as  'setsum (%x. e) {..<k}'
   208 
   209   Function 'Summation' over nat is gone, its syntax '\<Sum>i<k. e'
   210   now translates into 'setsum' as above.
   211 
   212 * HOL/Simplifier: Is now set up to reason about transitivity chains
   213   involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
   214   provided by Provers/trancl.ML as additional solvers.
   215   INCOMPATIBILITY: old proofs break occasionally as simplification may
   216   now solve more goals than previously.
   217 
   218 * HOL: new 'isatool dimacs2hol' to convert files in DIMACS CNF format
   219   (containing Boolean satisfiability problems) into Isabelle/HOL theories.
   220 
   221 
   222 *** HOLCF ***
   223 
   224 * HOLCF: discontinued special version of 'constdefs' (which used to
   225   support continuous functions) in favor of the general Pure one with
   226   full type-inference.
   227 
   228 
   229 *** ZF ***
   230 
   231 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the
   232   First Isomorphism Theorem (on quotienting by the kernel of a
   233   homomorphism).
   234 
   235 * ZF/Simplifier: install second copy of type solver that actually
   236   makes use of TC rules declared to Isar proof contexts (or locales);
   237   the old version is still required for ML proof scripts.
   238 
   239 
   240 
   241 New in Isabelle2004 (April 2004)
   242 --------------------------------
   243 
   244 *** General ***
   245 
   246 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   247   Replaces linorder.ML.
   248 
   249 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   250   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   251   (\<a>...\<z>), are now considered normal letters, and can therefore
   252   be used anywhere where an ASCII letter (a...zA...Z) has until
   253   now. COMPATIBILITY: This obviously changes the parsing of some
   254   terms, especially where a symbol has been used as a binder, say
   255   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   256   as an identifier.  Fix it by inserting a space around former
   257   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   258   existing theory and ML files.
   259 
   260 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   261 
   262 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   263   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   264   a normal (but invisible) letter. For multiple letter subscripts repeat
   265   \<^isub> like this: x\<^isub>1\<^isub>2.
   266 
   267 * Pure: There are now sub-/superscripts that can span more than one
   268   character. Text between \<^bsub> and \<^esub> is set in subscript in
   269   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   270   superscript. The new control characters are not identifier parts.
   271 
   272 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   273   content of "..." to the latex file instead of \isacntrl... . The "..."
   274   may consist of any printable characters excluding the end bracket >.
   275 
   276 * Pure: Using new Isar command "finalconsts" (or the ML functions
   277   Theory.add_finals or Theory.add_finals_i) it is now possible to
   278   declare constants "final", which prevents their being given a definition
   279   later.  It is useful for constants whose behaviour is fixed axiomatically
   280   rather than definitionally, such as the meta-logic connectives.
   281 
   282 * Pure: 'instance' now handles general arities with general sorts
   283   (i.e. intersections of classes),
   284 
   285 * Presentation: generated HTML now uses a CSS style sheet to make layout
   286   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   287   It can be changed to alter the colors/layout of generated pages.
   288 
   289 
   290 *** Isar ***
   291 
   292 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   293   cut_tac, subgoal_tac and thin_tac:
   294   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   295     locales are no longer forced to write Isar proof scripts.
   296     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   297     emulations.
   298   - INCOMPATIBILITY: names of variables to be instantiated may no
   299     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   300     This is consistent with the instantiation attribute "where".
   301 
   302 * Attributes "where" and "of":
   303   - Now take type variables of instantiated theorem into account when reading
   304     the instantiation string.  This fixes a bug that caused instantiated
   305     theorems to have too special types in some circumstances.
   306   - "where" permits explicit instantiations of type variables.
   307 
   308 * Calculation commands "moreover" and "also" no longer interfere with
   309   current facts ("this"), admitting arbitrary combinations with "then"
   310   and derived forms.
   311 
   312 * Locales:
   313   - Goal statements involving the context element "includes" no longer
   314     generate theorems with internal delta predicates (those ending on
   315     "_axioms") in the premise.
   316     Resolve particular premise with <locale>.intro to obtain old form.
   317   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   318     specification and "includes" elements in goal statement.
   319   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   320     [intro?] and [elim?] (respectively) by default.
   321   - Experimental command for instantiation of locales in proof contexts:
   322         instantiate <label>[<attrs>]: <loc>
   323     Instantiates locale <loc> and adds all its theorems to the current context
   324     taking into account their attributes.  Label and attrs are optional
   325     modifiers, like in theorem declarations.  If present, names of
   326     instantiated theorems are qualified with <label>, and the attributes
   327     <attrs> are applied after any attributes these theorems might have already.
   328       If the locale has assumptions, a chained fact of the form
   329     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   330     are derived.  The command does not support old-style locales declared
   331     with "locale (open)".
   332       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   333 
   334 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   335   (Isar) contexts.
   336 
   337 
   338 *** HOL ***
   339 
   340 * Proof import: new image HOL4 contains the imported library from
   341   the HOL4 system with about 2500 theorems. It is imported by
   342   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   343   can be used like any other Isabelle image.  See
   344   HOL/Import/HOL/README for more information.
   345 
   346 * Simplifier:
   347   - Much improved handling of linear and partial orders.
   348     Reasoners for linear and partial orders are set up for type classes
   349     "linorder" and "order" respectively, and are added to the default simpset
   350     as solvers.  This means that the simplifier can build transitivity chains
   351     to solve goals from the assumptions.
   352   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   353     of blast or auto after simplification become unnecessary because the goal
   354     is solved by simplification already.
   355 
   356 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   357     all proved in axiomatic type classes for semirings, rings and fields.
   358 
   359 * Numerics:
   360   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   361     now formalized using the Ring_and_Field theory mentioned above.
   362   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   363     than before, because now they are set up once in a generic manner.
   364   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   365     Look for the general versions in Ring_and_Field (and Power if they concern
   366     exponentiation).
   367 
   368 * Type "rat" of the rational numbers is now available in HOL-Complex.
   369 
   370 * Records:
   371   - Record types are now by default printed with their type abbreviation
   372     instead of the list of all field types. This can be configured via
   373     the reference "print_record_type_abbr".
   374   - Simproc "record_upd_simproc" for simplification of multiple updates added
   375     (not enabled by default).
   376   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   377     EX x. x = sel r to True (not enabled by default).
   378   - Tactic "record_split_simp_tac" to split and simplify records added.
   379 
   380 * 'specification' command added, allowing for definition by
   381   specification.  There is also an 'ax_specification' command that
   382   introduces the new constants axiomatically.
   383 
   384 * arith(_tac) is now able to generate counterexamples for reals as well.
   385 
   386 * HOL-Algebra: new locale "ring" for non-commutative rings.
   387 
   388 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   389   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   390 
   391 * HOL-Matrix: a first theory for matrices in HOL with an application of
   392   matrix theory to linear programming.
   393 
   394 * Unions and Intersections:
   395   The latex output syntax of UN and INT has been changed
   396   from "\Union x \in A. B" to "\Union_{x \in A} B"
   397   i.e. the index formulae has become a subscript.
   398   Similarly for "\Union x. B", and for \Inter instead of \Union.
   399 
   400 * Unions and Intersections over Intervals:
   401   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   402   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   403   like in normal math, and corresponding versions for < and for intersection.
   404 
   405 * ML: the legacy theory structures Int and List have been removed. They had
   406   conflicted with ML Basis Library structures having the same names.
   407 
   408 * 'refute' command added to search for (finite) countermodels.  Only works
   409   for a fragment of HOL.  The installation of an external SAT solver is
   410   highly recommended.  See "HOL/Refute.thy" for details.
   411 
   412 * 'quickcheck' command: Allows to find counterexamples by evaluating
   413   formulae under an assignment of free variables to random values.
   414   In contrast to 'refute', it can deal with inductive datatypes,
   415   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   416   for examples.
   417 
   418 
   419 *** HOLCF ***
   420 
   421 * Streams now come with concatenation and are part of the HOLCF image
   422 
   423 
   424 
   425 New in Isabelle2003 (May 2003)
   426 ------------------------------
   427 
   428 *** General ***
   429 
   430 * Provers/simplifier:
   431 
   432   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   433     Assumptions are now subject to complete mutual simplification,
   434     not just from left to right. The simplifier now preserves
   435     the order of assumptions.
   436 
   437     Potential INCOMPATIBILITY:
   438 
   439     -- simp sometimes diverges where the old version did
   440        not, e.g. invoking simp on the goal
   441 
   442         [| P (f x); y = x; f x = f y |] ==> Q
   443 
   444        now gives rise to the infinite reduction sequence
   445 
   446         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   447 
   448        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   449        kind of problem.
   450 
   451     -- Tactics combining classical reasoner and simplification (such as auto)
   452        are also affected by this change, because many of them rely on
   453        simp. They may sometimes diverge as well or yield a different numbers
   454        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   455        in case of problems. Sometimes subsequent calls to the classical
   456        reasoner will fail because a preceeding call to the simplifier too
   457        eagerly simplified the goal, e.g. deleted redundant premises.
   458 
   459   - The simplifier trace now shows the names of the applied rewrite rules
   460 
   461   - You can limit the number of recursive invocations of the simplifier
   462     during conditional rewriting (where the simplifie tries to solve the
   463     conditions before applying the rewrite rule):
   464     ML "simp_depth_limit := n"
   465     where n is an integer. Thus you can force termination where previously
   466     the simplifier would diverge.
   467 
   468   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   469 
   470   - No longer aborts on failed congruence proof.  Instead, the
   471     congruence is ignored.
   472 
   473 * Pure: New generic framework for extracting programs from constructive
   474   proofs. See HOL/Extraction.thy for an example instantiation, as well
   475   as HOL/Extraction for some case studies.
   476 
   477 * Pure: The main goal of the proof state is no longer shown by default, only
   478 the subgoals. This behaviour is controlled by a new flag.
   479    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   480 (ML: Proof.show_main_goal).
   481 
   482 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   483 rules whose conclusion matches subgoal 1:
   484       PG menu: Isabelle/Isar -> Show me -> matching rules
   485 The rules are ordered by how closely they match the subgoal.
   486 In particular, rules that solve a subgoal outright are displayed first
   487 (or rather last, the way they are printed).
   488 (ML: ProofGeneral.print_intros())
   489 
   490 * Pure: New flag trace_unify_fail causes unification to print
   491 diagnostic information (PG: in trace buffer) when it fails. This is
   492 useful for figuring out why single step proofs like rule, erule or
   493 assumption failed.
   494 
   495 * Pure: Locale specifications now produce predicate definitions
   496 according to the body of text (covering assumptions modulo local
   497 definitions); predicate "loc_axioms" covers newly introduced text,
   498 while "loc" is cumulative wrt. all included locale expressions; the
   499 latter view is presented only on export into the global theory
   500 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   501 on the old view without predicates;
   502 
   503 * Pure: predefined locales "var" and "struct" are useful for sharing
   504 parameters (as in CASL, for example); just specify something like
   505 ``var x + var y + struct M'' as import;
   506 
   507 * Pure: improved thms_containing: proper indexing of facts instead of
   508 raw theorems; check validity of results wrt. current name space;
   509 include local facts of proof configuration (also covers active
   510 locales), cover fixed variables in index; may use "_" in term
   511 specification; an optional limit for the number of printed facts may
   512 be given (the default is 40);
   513 
   514 * Pure: disallow duplicate fact bindings within new-style theory files
   515 (batch-mode only);
   516 
   517 * Provers: improved induct method: assumptions introduced by case
   518 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   519 the goal statement); "foo" still refers to all facts collectively;
   520 
   521 * Provers: the function blast.overloaded has been removed: all constants
   522 are regarded as potentially overloaded, which improves robustness in exchange
   523 for slight decrease in efficiency;
   524 
   525 * Provers/linorder: New generic prover for transitivity reasoning over
   526 linear orders.  Note: this prover is not efficient!
   527 
   528 * Isar: preview of problems to finish 'show' now produce an error
   529 rather than just a warning (in interactive mode);
   530 
   531 
   532 *** HOL ***
   533 
   534 * arith(_tac)
   535 
   536  - Produces a counter example if it cannot prove a goal.
   537    Note that the counter example may be spurious if the goal is not a formula
   538    of quantifier-free linear arithmetic.
   539    In ProofGeneral the counter example appears in the trace buffer.
   540 
   541  - Knows about div k and mod k where k is a numeral of type nat or int.
   542 
   543  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   544    linear arithmetic fails. This takes account of quantifiers and divisibility.
   545    Presburger arithmetic can also be called explicitly via presburger(_tac).
   546 
   547 * simp's arithmetic capabilities have been enhanced a bit: it now
   548 takes ~= in premises into account (by performing a case split);
   549 
   550 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   551 are distributed over a sum of terms;
   552 
   553 * New tactic "trans_tac" and method "trans" instantiate
   554 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   555 "<=", "<" and "=").
   556 
   557 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   558 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   559 
   560 * 'typedef' command has new option "open" to suppress the set
   561 definition;
   562 
   563 * functions Min and Max on finite sets have been introduced (theory
   564 Finite_Set);
   565 
   566 * attribute [symmetric] now works for relations as well; it turns
   567 (x,y) : R^-1 into (y,x) : R, and vice versa;
   568 
   569 * induct over a !!-quantified statement (say !!x1..xn):
   570   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   571 
   572 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   573 %x. None. Warning: empty_def now refers to the previously hidden definition
   574 of the empty set.
   575 
   576 * Algebra: formalization of classical algebra.  Intended as base for
   577 any algebraic development in Isabelle.  Currently covers group theory
   578 (up to Sylow's theorem) and ring theory (Universal Property of
   579 Univariate Polynomials).  Contributions welcome;
   580 
   581 * GroupTheory: deleted, since its material has been moved to Algebra;
   582 
   583 * Complex: new directory of the complex numbers with numeric constants,
   584 nonstandard complex numbers, and some complex analysis, standard and
   585 nonstandard (Jacques Fleuriot);
   586 
   587 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   588 
   589 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   590 Fleuriot);
   591 
   592 * Real/HahnBanach: updated and adapted to locales;
   593 
   594 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   595 Gray and Kramer);
   596 
   597 * UNITY: added the Meier-Sanders theory of progress sets;
   598 
   599 * MicroJava: bytecode verifier and lightweight bytecode verifier
   600 as abstract algorithms, instantiated to the JVM;
   601 
   602 * Bali: Java source language formalization. Type system, operational
   603 semantics, axiomatic semantics. Supported language features:
   604 classes, interfaces, objects,virtual methods, static methods,
   605 static/instance fields, arrays, access modifiers, definite
   606 assignment, exceptions.
   607 
   608 
   609 *** ZF ***
   610 
   611 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   612 universe, etc.);
   613 
   614 * Main ZF: virtually all theories converted to new-style format;
   615 
   616 
   617 *** ML ***
   618 
   619 * Pure: Tactic.prove provides sane interface for internal proofs;
   620 omits the infamous "standard" operation, so this is more appropriate
   621 than prove_goalw_cterm in many situations (e.g. in simprocs);
   622 
   623 * Pure: improved error reporting of simprocs;
   624 
   625 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   626 up simprocs;
   627 
   628 
   629 *** Document preparation ***
   630 
   631 * uses \par instead of \\ for line breaks in theory text. This may
   632 shift some page breaks in large documents. To get the old behaviour
   633 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   634 
   635 * minimized dependencies of isabelle.sty and isabellesym.sty on
   636 other packages
   637 
   638 * \<euro> now needs package babel/greek instead of marvosym (which
   639 broke \Rightarrow)
   640 
   641 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   642 textcomp package)
   643 
   644 
   645 
   646 New in Isabelle2002 (March 2002)
   647 --------------------------------
   648 
   649 *** Document preparation ***
   650 
   651 * greatly simplified document preparation setup, including more
   652 graceful interpretation of isatool usedir -i/-d/-D options, and more
   653 instructive isatool mkdir; users should basically be able to get
   654 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   655 users may run a separate document processing stage manually like this:
   656 "isatool usedir -D output HOL Test && isatool document Test/output";
   657 
   658 * theory dependency graph may now be incorporated into documents;
   659 isatool usedir -g true will produce session_graph.eps/.pdf for use
   660 with \includegraphics of LaTeX;
   661 
   662 * proper spacing of consecutive markup elements, especially text
   663 blocks after section headings;
   664 
   665 * support bold style (for single symbols only), input syntax is like
   666 this: "\<^bold>\<alpha>" or "\<^bold>A";
   667 
   668 * \<bullet> is now output as bold \cdot by default, which looks much
   669 better in printed text;
   670 
   671 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   672 note that these symbols are currently unavailable in Proof General /
   673 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   674 
   675 * isatool latex no longer depends on changed TEXINPUTS, instead
   676 isatool document copies the Isabelle style files to the target
   677 location;
   678 
   679 
   680 *** Isar ***
   681 
   682 * Pure/Provers: improved proof by cases and induction;
   683   - 'case' command admits impromptu naming of parameters (such as
   684     "case (Suc n)");
   685   - 'induct' method divinates rule instantiation from the inductive
   686     claim; no longer requires excessive ?P bindings for proper
   687     instantiation of cases;
   688   - 'induct' method properly enumerates all possibilities of set/type
   689     rules; as a consequence facts may be also passed through *type*
   690     rules without further ado;
   691   - 'induct' method now derives symbolic cases from the *rulified*
   692     rule (before it used to rulify cases stemming from the internal
   693     atomized version); this means that the context of a non-atomic
   694     statement becomes is included in the hypothesis, avoiding the
   695     slightly cumbersome show "PROP ?case" form;
   696   - 'induct' may now use elim-style induction rules without chaining
   697     facts, using ``missing'' premises from the goal state; this allows
   698     rules stemming from inductive sets to be applied in unstructured
   699     scripts, while still benefitting from proper handling of non-atomic
   700     statements; NB: major inductive premises need to be put first, all
   701     the rest of the goal is passed through the induction;
   702   - 'induct' proper support for mutual induction involving non-atomic
   703     rule statements (uses the new concept of simultaneous goals, see
   704     below);
   705   - append all possible rule selections, but only use the first
   706     success (no backtracking);
   707   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   708   - undeclared rule case names default to numbers 1, 2, 3, ...;
   709   - added 'print_induct_rules' (covered by help item in recent Proof
   710     General versions);
   711   - moved induct/cases attributes to Pure, methods to Provers;
   712   - generic method setup instantiated for FOL and HOL;
   713 
   714 * Pure: support multiple simultaneous goal statements, for example
   715 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   716 meta-level mechanism, this acts as if several individual goals had
   717 been stated separately; in particular common proof methods need to be
   718 repeated in order to cover all claims; note that a single elimination
   719 step is *not* sufficient to establish the two conjunctions, so this
   720 fails:
   721 
   722   assume "A & B" then have A and B ..   (*".." fails*)
   723 
   724 better use "obtain" in situations as above; alternative refer to
   725 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   726 
   727 * Pure: proper integration with ``locales''; unlike the original
   728 version by Florian Kammller, Isar locales package high-level proof
   729 contexts rather than raw logical ones (e.g. we admit to include
   730 attributes everywhere); operations on locales include merge and
   731 rename; support for implicit arguments (``structures''); simultaneous
   732 type-inference over imports and text; see also HOL/ex/Locales.thy for
   733 some examples;
   734 
   735 * Pure: the following commands have been ``localized'', supporting a
   736 target locale specification "(in name)": 'lemma', 'theorem',
   737 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   738 stored both within the locale and at the theory level (exported and
   739 qualified by the locale name);
   740 
   741 * Pure: theory goals may now be specified in ``long'' form, with
   742 ad-hoc contexts consisting of arbitrary locale elements. for example
   743 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   744 definitions may be given, too); the result is a meta-level rule with
   745 the context elements being discharged in the obvious way;
   746 
   747 * Pure: new proof command 'using' allows to augment currently used
   748 facts after a goal statement ('using' is syntactically analogous to
   749 'apply', but acts on the goal's facts only); this allows chained facts
   750 to be separated into parts given before and after a claim, as in
   751 ``from a and b have C using d and e <proof>'';
   752 
   753 * Pure: renamed "antecedent" case to "rule_context";
   754 
   755 * Pure: new 'judgment' command records explicit information about the
   756 object-logic embedding (used by several tools internally); no longer
   757 use hard-wired "Trueprop";
   758 
   759 * Pure: added 'corollary' command;
   760 
   761 * Pure: fixed 'token_translation' command;
   762 
   763 * Pure: removed obsolete 'exported' attribute;
   764 
   765 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   766 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   767 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   768 
   769 * Pure: method 'atomize' presents local goal premises as object-level
   770 statements (atomic meta-level propositions); setup controlled via
   771 rewrite rules declarations of 'atomize' attribute; example
   772 application: 'induct' method with proper rule statements in improper
   773 proof *scripts*;
   774 
   775 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   776 now consider the syntactic context of assumptions, giving a better
   777 chance to get type-inference of the arguments right (this is
   778 especially important for locales);
   779 
   780 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   781 mode;
   782 
   783 * Pure/obtain: the formal conclusion "thesis", being marked as
   784 ``internal'', may no longer be reference directly in the text;
   785 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   786 situations;
   787 
   788 * Pure: generic 'sym' attribute which declares a rule both as pure
   789 'elim?' and for the 'symmetric' operation;
   790 
   791 * Pure: marginal comments ``--'' may now occur just anywhere in the
   792 text; the fixed correlation with particular command syntax has been
   793 discontinued;
   794 
   795 * Pure: new method 'rules' is particularly well-suited for proof
   796 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   797 but often produces more compact proof terms with less detours;
   798 
   799 * Pure/Provers/classical: simplified integration with pure rule
   800 attributes and methods; the classical "intro?/elim?/dest?"
   801 declarations coincide with the pure ones; the "rule" method no longer
   802 includes classically swapped intros; "intro" and "elim" methods no
   803 longer pick rules from the context; also got rid of ML declarations
   804 AddXIs/AddXEs/AddXDs; all of this has some potential for
   805 INCOMPATIBILITY;
   806 
   807 * Provers/classical: attribute 'swapped' produces classical inversions
   808 of introduction rules;
   809 
   810 * Provers/simplifier: 'simplified' attribute may refer to explicit
   811 rules instead of full simplifier context; 'iff' attribute handles
   812 conditional rules;
   813 
   814 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   815 
   816 * HOL: 'recdef' now fails on unfinished automated proofs, use
   817 "(permissive)" option to recover old behavior;
   818 
   819 * HOL: 'inductive' no longer features separate (collective) attributes
   820 for 'intros' (was found too confusing);
   821 
   822 * HOL: properly declared induction rules less_induct and
   823 wf_induct_rule;
   824 
   825 
   826 *** HOL ***
   827 
   828 * HOL: moved over to sane numeral syntax; the new policy is as
   829 follows:
   830 
   831   - 0 and 1 are polymorphic constants, which are defined on any
   832   numeric type (nat, int, real etc.);
   833 
   834   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   835   binary representation internally;
   836 
   837   - type nat has special constructor Suc, and generally prefers Suc 0
   838   over 1::nat and Suc (Suc 0) over 2::nat;
   839 
   840 This change may cause significant problems of INCOMPATIBILITY; here
   841 are some hints on converting existing sources:
   842 
   843   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   844   entities, so expressions involving "-" (unary or binary minus) need
   845   to be spaced properly;
   846 
   847   - existing occurrences of "1" may need to be constraint "1::nat" or
   848   even replaced by Suc 0; similar for old "2";
   849 
   850   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   851 
   852   - remove all special provisions on numerals in proofs;
   853 
   854 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   855 representation (depends on bin_arith_simps in the default context);
   856 
   857 * HOL: symbolic syntax for x^2 (numeral 2);
   858 
   859 * HOL: the class of all HOL types is now called "type" rather than
   860 "term"; INCOMPATIBILITY, need to adapt references to this type class
   861 in axclass/classes, instance/arities, and (usually rare) occurrences
   862 in typings (of consts etc.); internally the class is called
   863 "HOL.type", ML programs should refer to HOLogic.typeS;
   864 
   865 * HOL/record package improvements:
   866   - new derived operations "fields" to build a partial record section,
   867     "extend" to promote a fixed record to a record scheme, and
   868     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   869     declared as simp by default;
   870   - shared operations ("more", "fields", etc.) now need to be always
   871     qualified) --- potential INCOMPATIBILITY;
   872   - removed "make_scheme" operations (use "make" with "extend") --
   873     INCOMPATIBILITY;
   874   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   875   - provides cases/induct rules for use with corresponding Isar
   876     methods (for concrete records, record schemes, concrete more
   877     parts, and schematic more parts -- in that order);
   878   - internal definitions directly based on a light-weight abstract
   879     theory of product types over typedef rather than datatype;
   880 
   881 * HOL: generic code generator for generating executable ML code from
   882 specifications; specific support for HOL constructs such as inductive
   883 datatypes and sets, as well as recursive functions; can be invoked
   884 via 'generate_code' theory section;
   885 
   886 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   887 
   888 * HOL: consolidated and renamed several theories.  In particular:
   889         Ord.thy has been absorbed into HOL.thy
   890         String.thy has been absorbed into List.thy
   891 
   892 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   893 (beware of argument permutation!);
   894 
   895 * HOL: linorder_less_split superseded by linorder_cases;
   896 
   897 * HOL/List: "nodups" renamed to "distinct";
   898 
   899 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   900 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   901   - Ex_def has changed, now need to use some_eq_ex
   902 
   903 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   904 in this (rare) case use:
   905 
   906   delSWrapper "split_all_tac"
   907   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   908 
   909 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   910 MAY FAIL;
   911 
   912 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   913 Isabelle's type classes, ^ on functions and relations has too general
   914 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   915 necessary to attach explicit type constraints;
   916 
   917 * HOL/Relation: the prefix name of the infix "O" has been changed from
   918 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   919 renamed accordingly (eg "compI" -> "rel_compI").
   920 
   921 * HOL: syntax translations now work properly with numerals and records
   922 expressions;
   923 
   924 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   925 of "lam" -- INCOMPATIBILITY;
   926 
   927 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   928 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   929 renamed "Product_Type.unit";
   930 
   931 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   932 
   933 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   934 the "cases" method);
   935 
   936 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   937 Florian Kammller);
   938 
   939 * HOL/IMP: updated and converted to new-style theory format; several
   940 parts turned into readable document, with proper Isar proof texts and
   941 some explanations (by Gerwin Klein);
   942 
   943 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   944 
   945 * HOL-Hyperreal is now a logic image;
   946 
   947 
   948 *** HOLCF ***
   949 
   950 * Isar: consts/constdefs supports mixfix syntax for continuous
   951 operations;
   952 
   953 * Isar: domain package adapted to new-style theory format, e.g. see
   954 HOLCF/ex/Dnat.thy;
   955 
   956 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   957 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   958 lift.induct_tac, always use UU instead of Undef;
   959 
   960 * HOLCF/IMP: updated and converted to new-style theory;
   961 
   962 
   963 *** ZF ***
   964 
   965 * Isar: proper integration of logic-specific tools and packages,
   966 including theory commands '(co)inductive', '(co)datatype',
   967 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   968 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   969 
   970 * theory Main no longer includes AC; for the Axiom of Choice, base
   971 your theory on Main_ZFC;
   972 
   973 * the integer library now covers quotients and remainders, with many
   974 laws relating division to addition, multiplication, etc.;
   975 
   976 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   977 typeless version of the formalism;
   978 
   979 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   980 format;
   981 
   982 * ZF/Induct: new directory for examples of inductive definitions,
   983 including theory Multiset for multiset orderings; converted to
   984 new-style theory format;
   985 
   986 * ZF: many new theorems about lists, ordinals, etc.;
   987 
   988 
   989 *** General ***
   990 
   991 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   992 variable proof controls level of detail: 0 = no proofs (only oracle
   993 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   994 also ref manual for further ML interfaces;
   995 
   996 * Pure/axclass: removed obsolete ML interface
   997 goal_subclass/goal_arity;
   998 
   999 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1000 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1001 separate tokens, so expressions involving minus need to be spaced
  1002 properly;
  1003 
  1004 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1005 rather than "infixl" or "infixr";
  1006 
  1007 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1008 sort constraint specifications in type inference; e.g. "x::_::foo"
  1009 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1010 type variable);
  1011 
  1012 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1013 control output of nested => (types); the default behavior is
  1014 "type_brackets";
  1015 
  1016 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1017 tokens into AST constants;
  1018 
  1019 * Pure/syntax: prefer later declarations of translations and print
  1020 translation functions; potential INCOMPATIBILITY: need to reverse
  1021 multiple declarations for same syntax element constant;
  1022 
  1023 * Pure/show_hyps reset by default (in accordance to existing Isar
  1024 practice);
  1025 
  1026 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1027 addSafter;
  1028 
  1029 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1030 as well;
  1031 
  1032 * system: tested support for MacOS X; should be able to get Isabelle +
  1033 Proof General to work in a plain Terminal after installing Poly/ML
  1034 (e.g. from the Isabelle distribution area) and GNU bash alone
  1035 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1036 support requires further installations, e.g. from
  1037 http://fink.sourceforge.net/);
  1038 
  1039 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1040 
  1041 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1042 of 40 MB), cf. ML_OPTIONS;
  1043 
  1044 * system: Proof General keywords specification is now part of the
  1045 Isabelle distribution (see etc/isar-keywords.el);
  1046 
  1047 * system: support for persistent Proof General sessions (refrain from
  1048 outdating all loaded theories on startup); user may create writable
  1049 logic images like this: ``isabelle -q HOL Test'';
  1050 
  1051 * system: smart selection of Isabelle process versus Isabelle
  1052 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1053 run both "isabelle" and "Isabelle" even if file names are badly
  1054 damaged (executable inspects the case of the first letter of its own
  1055 name); added separate "isabelle-process" and "isabelle-interface";
  1056 
  1057 * system: refrain from any attempt at filtering input streams; no
  1058 longer support ``8bit'' encoding of old isabelle font, instead proper
  1059 iso-latin characters may now be used; the related isatools
  1060 "symbolinput" and "nonascii" have disappeared as well;
  1061 
  1062 * system: removed old "xterm" interface (the print modes "xterm" and
  1063 "xterm_color" are still available for direct use in a suitable
  1064 terminal);
  1065 
  1066 
  1067 
  1068 New in Isabelle99-2 (February 2001)
  1069 -----------------------------------
  1070 
  1071 *** Overview of INCOMPATIBILITIES ***
  1072 
  1073 * HOL: please note that theories in the Library and elsewhere often use the
  1074 new-style (Isar) format; to refer to their theorems in an ML script you must
  1075 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1076 
  1077 * HOL: inductive package no longer splits induction rule aggressively,
  1078 but only as far as specified by the introductions given; the old
  1079 format may be recovered via ML function complete_split_rule or attribute
  1080 'split_rule (complete)';
  1081 
  1082 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1083 gfp_Tarski to gfp_unfold;
  1084 
  1085 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1086 
  1087 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1088 relation); infix "^^" has been renamed "``"; infix "``" has been
  1089 renamed "`"; "univalent" has been renamed "single_valued";
  1090 
  1091 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1092 operation;
  1093 
  1094 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1095 
  1096 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1097 
  1098 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1099 consequence, it is no longer monotonic wrt. the local goal context
  1100 (which is now passed through the inductive cases);
  1101 
  1102 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1103 \<gg> to \<ggreater>;
  1104 
  1105 
  1106 *** Document preparation ***
  1107 
  1108 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1109 available: are "it" for near math-mode best-style output, "sl" for
  1110 slanted text style, and "tt" for plain type-writer; if no
  1111 \isabellestyle command is given, output is according to slanted
  1112 type-writer);
  1113 
  1114 * support sub/super scripts (for single symbols only), input syntax is
  1115 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1116 
  1117 * some more standard symbols; see Appendix A of the system manual for
  1118 the complete list of symbols defined in isabellesym.sty;
  1119 
  1120 * improved isabelle style files; more abstract symbol implementation
  1121 (should now use \isamath{...} and \isatext{...} in custom symbol
  1122 definitions);
  1123 
  1124 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1125 state; Note that presentation of goal states does not conform to
  1126 actual human-readable proof documents.  Please do not include goal
  1127 states into document output unless you really know what you are doing!
  1128 
  1129 * proper indentation of antiquoted output with proportional LaTeX
  1130 fonts;
  1131 
  1132 * no_document ML operator temporarily disables LaTeX document
  1133 generation;
  1134 
  1135 * isatool unsymbolize tunes sources for plain ASCII communication;
  1136 
  1137 
  1138 *** Isar ***
  1139 
  1140 * Pure: Isar now suffers initial goal statements to contain unbound
  1141 schematic variables (this does not conform to actual readable proof
  1142 documents, due to unpredictable outcome and non-compositional proof
  1143 checking); users who know what they are doing may use schematic goals
  1144 for Prolog-style synthesis of proven results;
  1145 
  1146 * Pure: assumption method (an implicit finishing) now handles actual
  1147 rules as well;
  1148 
  1149 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1150 initial goal, declare "that" only as Pure intro (only for single
  1151 steps); the "that" rule assumption may now be involved in implicit
  1152 finishing, thus ".." becomes a feasible for trivial obtains;
  1153 
  1154 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1155 instance proofs may be performed by "..";
  1156 
  1157 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1158 statements as well;
  1159 
  1160 * Pure: more robust selection of calculational rules;
  1161 
  1162 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1163 rule (as well as the assumption rule);
  1164 
  1165 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1166 lemmas, using the graph browser tool;
  1167 
  1168 * Pure: predict failure of "show" in interactive mode;
  1169 
  1170 * Pure: 'thms_containing' now takes actual terms as arguments;
  1171 
  1172 * HOL: improved method 'induct' --- now handles non-atomic goals
  1173 (potential INCOMPATIBILITY); tuned error handling;
  1174 
  1175 * HOL: cases and induct rules now provide explicit hints about the
  1176 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1177 any remaining facts are inserted into the goal verbatim;
  1178 
  1179 * HOL: local contexts (aka cases) may now contain term bindings as
  1180 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1181 the result to be shown in each case;
  1182 
  1183 * HOL: added 'recdef_tc' command;
  1184 
  1185 * isatool convert assists in eliminating legacy ML scripts;
  1186 
  1187 
  1188 *** HOL ***
  1189 
  1190 * HOL/Library: a collection of generic theories to be used together
  1191 with main HOL; the theory loader path already includes this directory
  1192 by default; the following existing theories have been moved here:
  1193 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1194 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1195 
  1196 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1197 modelling and verification task performed in Isabelle/HOL +
  1198 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1199 
  1200 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1201 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1202 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1203 'domain', this makes the theory consistent with mathematical
  1204 literature;
  1205 
  1206 * HOL basics: added overloaded operations "inverse" and "divide"
  1207 (infix "/"), syntax for generic "abs" operation, generic summation
  1208 operator \<Sum>;
  1209 
  1210 * HOL/typedef: simplified package, provide more useful rules (see also
  1211 HOL/subset.thy);
  1212 
  1213 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1214 now expressed as a proper nested rule (old-style tactic scripts may
  1215 require atomize_strip_tac to cope with non-atomic premises);
  1216 
  1217 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1218 to "split_conv" (old name still available for compatibility);
  1219 
  1220 * HOL: improved concrete syntax for strings (e.g. allows translation
  1221 rules with string literals);
  1222 
  1223 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1224  and Fleuriot's mechanization of analysis, including the transcendental
  1225  functions for the reals;
  1226 
  1227 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1228 
  1229 
  1230 *** CTT ***
  1231 
  1232 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1233 "lam" is displayed as TWO lambda-symbols
  1234 
  1235 * CTT: theory Main now available, containing everything (that is, Bool
  1236 and Arith);
  1237 
  1238 
  1239 *** General ***
  1240 
  1241 * Pure: the Simplifier has been implemented properly as a derived rule
  1242 outside of the actual kernel (at last!); the overall performance
  1243 penalty in practical applications is about 50%, while reliability of
  1244 the Isabelle inference kernel has been greatly improved;
  1245 
  1246 * print modes "brackets" and "no_brackets" control output of nested =>
  1247 (types) and ==> (props); the default behaviour is "brackets";
  1248 
  1249 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1250 as assumptions as well;
  1251 
  1252 * system: support Poly/ML 4.0;
  1253 
  1254 * system: isatool install handles KDE version 1 or 2;
  1255 
  1256 
  1257 
  1258 New in Isabelle99-1 (October 2000)
  1259 ----------------------------------
  1260 
  1261 *** Overview of INCOMPATIBILITIES ***
  1262 
  1263 * HOL: simplification of natural numbers is much changed; to partly
  1264 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1265 issue the following ML commands:
  1266 
  1267   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1268   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1269 
  1270 * HOL: simplification no longer dives into case-expressions; this is
  1271 controlled by "t.weak_case_cong" for each datatype t;
  1272 
  1273 * HOL: nat_less_induct renamed to less_induct;
  1274 
  1275 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1276 fixsome to patch .thy and .ML sources automatically;
  1277 
  1278   select_equality  -> some_equality
  1279   select_eq_Ex     -> some_eq_ex
  1280   selectI2EX       -> someI2_ex
  1281   selectI2         -> someI2
  1282   selectI          -> someI
  1283   select1_equality -> some1_equality
  1284   Eps_sym_eq       -> some_sym_eq_trivial
  1285   Eps_eq           -> some_eq_trivial
  1286 
  1287 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1288 
  1289 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1290 instead);
  1291 
  1292 * HOL: the recursion equations generated by 'recdef' are now called
  1293 f.simps instead of f.rules;
  1294 
  1295 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1296 
  1297 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1298 sometimes be needed;
  1299 
  1300 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1301 
  1302 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1303 
  1304 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1305 product is now "<*>" instead of "Times"; the lexicographic product is
  1306 now "<*lex*>" instead of "**";
  1307 
  1308 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1309 of main HOL, but was unused); better use HOL's datatype package;
  1310 
  1311 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1312 the old syntax may be recovered as follows:
  1313 
  1314   syntax (symbols)
  1315     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1316       (infixl "\\<oplus>" 100)
  1317 
  1318 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1319 
  1320 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1321 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1322 internally;
  1323 
  1324 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1325 changed from A/r to A//r;
  1326 
  1327 * ZF: new treatment of arithmetic (nat & int) may break some old
  1328 proofs;
  1329 
  1330 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1331 rulify -> rule_format, elimify -> elim_format, ...);
  1332 
  1333 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1334 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1335 should have to change intro!! to intro? only); replaced "delrule" by
  1336 "rule del";
  1337 
  1338 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1339 
  1340 * Provers: strengthened force_tac by using new first_best_tac;
  1341 
  1342 * LaTeX document preparation: several changes of isabelle.sty (see
  1343 lib/texinputs);
  1344 
  1345 
  1346 *** Document preparation ***
  1347 
  1348 * formal comments (text blocks etc.) in new-style theories may now
  1349 contain antiquotations of thm/prop/term/typ/text to be presented
  1350 according to latex print mode; concrete syntax is like this:
  1351 @{term[show_types] "f(x) = a + x"};
  1352 
  1353 * isatool mkdir provides easy setup of Isabelle session directories,
  1354 including proper document sources;
  1355 
  1356 * generated LaTeX sources are now deleted after successful run
  1357 (isatool document -c); may retain a copy somewhere else via -D option
  1358 of isatool usedir;
  1359 
  1360 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1361 style files, achieving self-contained LaTeX sources and simplifying
  1362 LaTeX debugging;
  1363 
  1364 * old-style theories now produce (crude) LaTeX output as well;
  1365 
  1366 * browser info session directories are now self-contained (may be put
  1367 on WWW server seperately); improved graphs of nested sessions; removed
  1368 graph for 'all sessions';
  1369 
  1370 * several improvements in isabelle style files; \isabellestyle{it}
  1371 produces fake math mode output; \isamarkupheader is now \section by
  1372 default; see lib/texinputs/isabelle.sty etc.;
  1373 
  1374 
  1375 *** Isar ***
  1376 
  1377 * Isar/Pure: local results and corresponding term bindings are now
  1378 subject to Hindley-Milner polymorphism (similar to ML); this
  1379 accommodates incremental type-inference very nicely;
  1380 
  1381 * Isar/Pure: new derived language element 'obtain' supports
  1382 generalized existence reasoning;
  1383 
  1384 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1385 support accumulation of results, without applying any rules yet;
  1386 useful to collect intermediate results without explicit name
  1387 references, and for use with transitivity rules with more than 2
  1388 premises;
  1389 
  1390 * Isar/Pure: scalable support for case-analysis type proofs: new
  1391 'case' language element refers to local contexts symbolically, as
  1392 produced by certain proof methods; internally, case names are attached
  1393 to theorems as "tags";
  1394 
  1395 * Isar/Pure: theory command 'hide' removes declarations from
  1396 class/type/const name spaces;
  1397 
  1398 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1399 indicate potential overloading;
  1400 
  1401 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1402 
  1403 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1404 "{a,b,c}" instead of {a,b,c};
  1405 
  1406 * Isar/Pure now provides its own version of intro/elim/dest
  1407 attributes; useful for building new logics, but beware of confusion
  1408 with the version in Provers/classical;
  1409 
  1410 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1411 case name 'antecedent';
  1412 
  1413 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1414 to the current context is now done automatically);
  1415 
  1416 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1417 for definining proof methods in ML;
  1418 
  1419 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1420 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1421 most cases, one should have to change intro!! to intro? only);
  1422 replaced "delrule" by "rule del";
  1423 
  1424 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1425 'symmetric' attribute (the latter supercedes [RS sym]);
  1426 
  1427 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1428 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1429 well (including splits);
  1430 
  1431 * Isar/Provers: Simplifier and Classical methods now support all kind
  1432 of modifiers used in the past, including 'cong', 'iff', etc.
  1433 
  1434 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1435 of Simplifier and Classical reasoner);
  1436 
  1437 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1438 now support named cases; major packages (inductive, datatype, primrec,
  1439 recdef) support case names and properly name parameters;
  1440 
  1441 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1442 monotonicity conditions are extracted to be proven at end of
  1443 calculations;
  1444 
  1445 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1446 method anyway;
  1447 
  1448 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1449 split_if split_if_asm; datatype package provides theorems foo.splits =
  1450 foo.split foo.split_asm for each datatype;
  1451 
  1452 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1453 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1454 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1455 use "(cases (simplified))" method in proper proof texts);
  1456 
  1457 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1458 
  1459 * Isar: names of theorems etc. may be natural numbers as well;
  1460 
  1461 * Isar: 'pr' command: optional arguments for goals_limit and
  1462 ProofContext.prems_limit; no longer prints theory contexts, but only
  1463 proof states;
  1464 
  1465 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1466 additional print modes to be specified; e.g. "pr(latex)" will print
  1467 proof state according to the Isabelle LaTeX style;
  1468 
  1469 * Isar: improved support for emulating tactic scripts, including proof
  1470 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1471 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1472 (for HOL datatypes);
  1473 
  1474 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1475 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1476 'proof method scripts' have to be in depth-first order;
  1477 
  1478 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1479 
  1480 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1481 should instead use individual commands for printing items
  1482 (print_commands, print_methods etc.);
  1483 
  1484 * Isar: added 'nothing' --- the empty list of theorems;
  1485 
  1486 
  1487 *** HOL ***
  1488 
  1489 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1490 corresponding virtual machine and a specification of its bytecode
  1491 verifier and a lightweight bytecode verifier, including proofs of
  1492 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1493 Cornelia Pusch (see also the homepage of project Bali at
  1494 http://isabelle.in.tum.de/Bali/);
  1495 
  1496 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1497 Clemens Ballarin;
  1498 
  1499 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1500 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1501 Rasmussen;
  1502 
  1503 * HOL/Lattice: fundamental concepts of lattice theory and order
  1504 structures, including duals, properties of bounds versus algebraic
  1505 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1506 Theorem for complete lattices etc.; may also serve as a demonstration
  1507 for abstract algebraic reasoning using axiomatic type classes, and
  1508 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1509 
  1510 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1511 von Oheimb;
  1512 
  1513 * HOL/IMPP: extension of IMP with local variables and mutually
  1514 recursive procedures, by David von Oheimb;
  1515 
  1516 * HOL/Lambda: converted into new-style theory and document;
  1517 
  1518 * HOL/ex/Multiquote: example of multiple nested quotations and
  1519 anti-quotations -- basically a generalized version of de-Bruijn
  1520 representation; very useful in avoiding lifting of operations;
  1521 
  1522 * HOL/record: added general record equality rule to simpset; fixed
  1523 select-update simplification procedure to handle extended records as
  1524 well; admit "r" as field name;
  1525 
  1526 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1527 other numeric types and also as the identity of groups, rings, etc.;
  1528 
  1529 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1530 Types nat and int belong to this axclass;
  1531 
  1532 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1533    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1534    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1535   two terms #m*u and #n*u are replaced by #(m+n)*u
  1536     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1537   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1538     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1539 
  1540 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1541 powerful prover for predicate logic but knows nothing of clasets; see
  1542 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1543 
  1544 * HOL: new version of "case_tac" subsumes both boolean case split and
  1545 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1546 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1547 
  1548 * HOL: simplification no longer dives into case-expressions: only the
  1549 selector expression is simplified, but not the remaining arms; to
  1550 enable full simplification of case-expressions for datatype t, you may
  1551 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1552 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1553 
  1554 * HOL/recdef: the recursion equations generated by 'recdef' for
  1555 function 'f' are now called f.simps instead of f.rules; if all
  1556 termination conditions are proved automatically, these simplification
  1557 rules are added to the simpset, as in primrec; rules may be named
  1558 individually as well, resulting in a separate list of theorems for
  1559 each equation;
  1560 
  1561 * HOL/While is a new theory that provides a while-combinator. It
  1562 permits the definition of tail-recursive functions without the
  1563 provision of a termination measure. The latter is necessary once the
  1564 invariant proof rule for while is applied.
  1565 
  1566 * HOL: new (overloaded) notation for the set of elements below/above
  1567 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1568 
  1569 * HOL: theorems impI, allI, ballI bound as "strip";
  1570 
  1571 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1572 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1573 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1574 
  1575 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1576 
  1577 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1578 main HOL, but was unused);
  1579 
  1580 * HOL: fewer consts declared as global (e.g. have to refer to
  1581 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1582 
  1583 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1584 in case of overlap with user translations (e.g. judgements over
  1585 tuples); (note that the underlying logical represenation is still
  1586 bogus);
  1587 
  1588 
  1589 *** ZF ***
  1590 
  1591 * ZF: simplification automatically cancels common terms in arithmetic
  1592 expressions over nat and int;
  1593 
  1594 * ZF: new treatment of nat to minimize type-checking: all operators
  1595 coerce their operands to a natural number using the function natify,
  1596 making the algebraic laws unconditional;
  1597 
  1598 * ZF: as above, for int: operators coerce their operands to an integer
  1599 using the function intify;
  1600 
  1601 * ZF: the integer library now contains many of the usual laws for the
  1602 orderings, including $<=, and monotonicity laws for $+ and $*;
  1603 
  1604 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1605 simplification;
  1606 
  1607 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1608 to the simplifier and classical reasoner simultaneously;
  1609 
  1610 
  1611 *** General ***
  1612 
  1613 * Provers: blast_tac now handles actual object-logic rules as
  1614 assumptions; note that auto_tac uses blast_tac internally as well;
  1615 
  1616 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1617 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1618 
  1619 * Provers: delrules now handles destruct rules as well (no longer need
  1620 explicit make_elim);
  1621 
  1622 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1623   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1624 use instead the strong form,
  1625   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1626 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1627 from destruct-rules;
  1628 
  1629 * Provers: Simplifier.easy_setup provides a fast path to basic
  1630 Simplifier setup for new object-logics;
  1631 
  1632 * Pure: AST translation rules no longer require constant head on LHS;
  1633 
  1634 * Pure: improved name spaces: ambiguous output is qualified; support
  1635 for hiding of names;
  1636 
  1637 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1638 XSYMBOL_HOME; no longer need to do manual configuration in most
  1639 situations;
  1640 
  1641 * system: compression of ML heaps images may now be controlled via -c
  1642 option of isabelle and isatool usedir (currently only observed by
  1643 Poly/ML);
  1644 
  1645 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1646 useful for remote X11);
  1647 
  1648 * system: provide TAGS file for Isabelle sources;
  1649 
  1650 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1651 order;
  1652 
  1653 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1654 timing flag supersedes proof_timing and Toplevel.trace;
  1655 
  1656 * ML: new combinators |>> and |>>> for incremental transformations
  1657 with secondary results (e.g. certain theory extensions):
  1658 
  1659 * ML: PureThy.add_defs gets additional argument to indicate potential
  1660 overloading (usually false);
  1661 
  1662 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1663 results;
  1664 
  1665 
  1666 
  1667 New in Isabelle99 (October 1999)
  1668 --------------------------------
  1669 
  1670 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1671 
  1672 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1673 are no longer simplified.  (This allows the simplifier to unfold recursive
  1674 functional programs.)  To restore the old behaviour, declare
  1675 
  1676     Delcongs [if_weak_cong];
  1677 
  1678 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1679 complement;
  1680 
  1681 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1682 
  1683 * HOL/datatype: mutual_induct_tac no longer exists --
  1684   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1685 
  1686 * HOL/typedef: fixed type inference for representing set; type
  1687 arguments now have to occur explicitly on the rhs as type constraints;
  1688 
  1689 * ZF: The con_defs part of an inductive definition may no longer refer
  1690 to constants declared in the same theory;
  1691 
  1692 * HOL, ZF: the function mk_cases, generated by the inductive
  1693 definition package, has lost an argument.  To simplify its result, it
  1694 uses the default simpset instead of a supplied list of theorems.
  1695 
  1696 * HOL/List: the constructors of type list are now Nil and Cons;
  1697 
  1698 * Simplifier: the type of the infix ML functions
  1699         setSSolver addSSolver setSolver addSolver
  1700 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1701 for packaging solvers. A solver is created via
  1702         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1703 where the string argument is only a comment.
  1704 
  1705 
  1706 *** Proof tools ***
  1707 
  1708 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1709 decision procedure for linear arithmetic. Currently it is used for
  1710 types `nat', `int', and `real' in HOL (see below); it can, should and
  1711 will be instantiated for other types and logics as well.
  1712 
  1713 * The simplifier now accepts rewrite rules with flexible heads, eg
  1714      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1715   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1716   matching.
  1717 
  1718 
  1719 *** General ***
  1720 
  1721 * New Isabelle/Isar subsystem provides an alternative to traditional
  1722 tactical theorem proving; together with the ProofGeneral/isar user
  1723 interface it offers an interactive environment for developing human
  1724 readable proof documents (Isar == Intelligible semi-automated
  1725 reasoning); for further information see isatool doc isar-ref,
  1726 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1727 
  1728 * improved and simplified presentation of theories: better HTML markup
  1729 (including colors), graph views in several sizes; isatool usedir now
  1730 provides a proper interface for user theories (via -P option); actual
  1731 document preparation based on (PDF)LaTeX is available as well (for
  1732 new-style theories only); see isatool doc system for more information;
  1733 
  1734 * native support for Proof General, both for classic Isabelle and
  1735 Isabelle/Isar;
  1736 
  1737 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1738 using the graph browser tool;
  1739 
  1740 * Isabelle manuals now also available as PDF;
  1741 
  1742 * theory loader rewritten from scratch (may not be fully
  1743 bug-compatible); old loadpath variable has been replaced by show_path,
  1744 add_path, del_path, reset_path functions; new operations such as
  1745 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1746 isatool doc ref);
  1747 
  1748 * improved isatool install: option -k creates KDE application icon,
  1749 option -p DIR installs standalone binaries;
  1750 
  1751 * added ML_PLATFORM setting (useful for cross-platform installations);
  1752 more robust handling of platform specific ML images for SML/NJ;
  1753 
  1754 * the settings environment is now statically scoped, i.e. it is never
  1755 created again in sub-processes invoked from isabelle, isatool, or
  1756 Isabelle;
  1757 
  1758 * path element specification '~~' refers to '$ISABELLE_HOME';
  1759 
  1760 * in locales, the "assumes" and "defines" parts may be omitted if
  1761 empty;
  1762 
  1763 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1764 long arrows);
  1765 
  1766 * new print_mode "HTML";
  1767 
  1768 * new flag show_tags controls display of tags of theorems (which are
  1769 basically just comments that may be attached by some tools);
  1770 
  1771 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1772 mode and goal output format:
  1773 
  1774 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1775 244c244
  1776 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1777 ---
  1778 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1779 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1780 181c181
  1781 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1782 ---
  1783 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1784 
  1785 * function bind_thms stores lists of theorems (cf. bind_thm);
  1786 
  1787 * new shorthand tactics ftac, eatac, datac, fatac;
  1788 
  1789 * qed (and friends) now accept "" as result name; in that case the
  1790 theorem is not stored, but proper checks and presentation of the
  1791 result still apply;
  1792 
  1793 * theorem database now also indexes constants "Trueprop", "all",
  1794 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1795 
  1796 
  1797 *** HOL ***
  1798 
  1799 ** HOL arithmetic **
  1800 
  1801 * There are now decision procedures for linear arithmetic over nat and
  1802 int:
  1803 
  1804 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1805 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1806 are treated as atomic; subformulae not involving type `nat' or `int'
  1807 are ignored; quantified subformulae are ignored unless they are
  1808 positive universal or negative existential. The tactic has to be
  1809 invoked by hand and can be a little bit slow. In particular, the
  1810 running time is exponential in the number of occurrences of `min' and
  1811 `max', and `-' on `nat'.
  1812 
  1813 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1814 (negated) (in)equalities among the premises and the conclusion into
  1815 account (i.e. no compound formulae) and does not know about `min' and
  1816 `max', and `-' on `nat'. It is fast and is used automatically by the
  1817 simplifier.
  1818 
  1819 NB: At the moment, these decision procedures do not cope with mixed
  1820 nat/int formulae where the two parts interact, such as `m < n ==>
  1821 int(m) < int(n)'.
  1822 
  1823 * HOL/Numeral provides a generic theory of numerals (encoded
  1824 efficiently as bit strings); setup for types nat/int/real is in place;
  1825 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1826 int, existing theories and proof scripts may require a few additional
  1827 type constraints;
  1828 
  1829 * integer division and remainder can now be performed on constant
  1830 arguments;
  1831 
  1832 * many properties of integer multiplication, division and remainder
  1833 are now available;
  1834 
  1835 * An interface to the Stanford Validity Checker (SVC) is available through the
  1836 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1837 are proved automatically.  SVC must be installed separately, and its results
  1838 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1839 invocation of the underlying oracle).  For SVC see
  1840   http://verify.stanford.edu/SVC
  1841 
  1842 * IsaMakefile: the HOL-Real target now builds an actual image;
  1843 
  1844 
  1845 ** HOL misc **
  1846 
  1847 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1848 (in Isabelle/Isar) -- by Gertrud Bauer;
  1849 
  1850 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1851 analysis for assembly languages with subtypes;
  1852 
  1853 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1854 -- avoids syntactic ambiguities and treats state, transition, and
  1855 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1856 changed syntax and (many) tactics;
  1857 
  1858 * HOL/inductive: Now also handles more general introduction rules such
  1859   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1860   theorems are now maintained within the theory (maintained via the
  1861   "mono" attribute);
  1862 
  1863 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1864   (using function types) such as
  1865 
  1866   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1867 
  1868 * HOL/record: record_simproc (part of the default simpset) takes care
  1869 of selectors applied to updated records; record_split_tac is no longer
  1870 part of the default claset; update_defs may now be removed from the
  1871 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1872 
  1873   claset_ref () := claset() addSWrapper record_split_wrapper;
  1874   Delsimprocs [record_simproc]
  1875 
  1876 * HOL/typedef: fixed type inference for representing set; type
  1877 arguments now have to occur explicitly on the rhs as type constraints;
  1878 
  1879 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1880 names rather than an ML expression;
  1881 
  1882 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1883 supplied later.  Program schemes can be defined, such as
  1884     "While B C s = (if B s then While B C (C s) else s)"
  1885 where the well-founded relation can be chosen after B and C have been given.
  1886 
  1887 * HOL/List: the constructors of type list are now Nil and Cons;
  1888 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1889 course, ML tools referring to List.list.op # etc. have to be adapted;
  1890 
  1891 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1892 disabled by default; run isabelle with option -m HOL to get back to
  1893 the original Gordon/HOL-style output;
  1894 
  1895 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1896 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1897 
  1898 * HOL basic syntax simplified (more orthogonal): all variants of
  1899 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1900 Eps operator is provided as well: "SOME x. P[x]";
  1901 
  1902 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1903 
  1904 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1905 thus available for user theories;
  1906 
  1907 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1908 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1909 time;
  1910 
  1911 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1912 several times and then mp;
  1913 
  1914 
  1915 *** LK ***
  1916 
  1917 * the notation <<...>> is now available as a notation for sequences of
  1918 formulas;
  1919 
  1920 * the simplifier is now installed
  1921 
  1922 * the axiom system has been generalized (thanks to Soren Heilmann)
  1923 
  1924 * the classical reasoner now has a default rule database
  1925 
  1926 
  1927 *** ZF ***
  1928 
  1929 * new primrec section allows primitive recursive functions to be given
  1930 directly (as in HOL) over datatypes and the natural numbers;
  1931 
  1932 * new tactics induct_tac and exhaust_tac for induction (or case
  1933 analysis) over datatypes and the natural numbers;
  1934 
  1935 * the datatype declaration of type T now defines the recursor T_rec;
  1936 
  1937 * simplification automatically does freeness reasoning for datatype
  1938 constructors;
  1939 
  1940 * automatic type-inference, with AddTCs command to insert new
  1941 type-checking rules;
  1942 
  1943 * datatype introduction rules are now added as Safe Introduction rules
  1944 to the claset;
  1945 
  1946 * the syntax "if P then x else y" is now available in addition to
  1947 if(P,x,y);
  1948 
  1949 
  1950 *** Internal programming interfaces ***
  1951 
  1952 * tuned simplifier trace output; new flag debug_simp;
  1953 
  1954 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1955 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1956 
  1957 * AxClass.axclass_tac lost the theory argument;
  1958 
  1959 * tuned current_goals_markers semantics: begin / end goal avoids
  1960 printing empty lines;
  1961 
  1962 * removed prs and prs_fn hook, which was broken because it did not
  1963 include \n in its semantics, forcing writeln to add one
  1964 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1965 string -> unit if you really want to output text without newline;
  1966 
  1967 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1968 plain output, interface builders may have to enable 'isabelle_font'
  1969 mode to get Isabelle font glyphs as before;
  1970 
  1971 * refined token_translation interface; INCOMPATIBILITY: output length
  1972 now of type real instead of int;
  1973 
  1974 * theory loader actions may be traced via new ThyInfo.add_hook
  1975 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1976 your own database of information attached to *whole* theories -- as
  1977 opposed to intra-theory data slots offered via TheoryDataFun;
  1978 
  1979 * proper handling of dangling sort hypotheses (at last!);
  1980 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1981 extra sort hypotheses that can be witnessed from the type signature;
  1982 the force_strip_shyps flag is gone, any remaining shyps are simply
  1983 left in the theorem (with a warning issued by strip_shyps_warning);
  1984 
  1985 
  1986 
  1987 New in Isabelle98-1 (October 1998)
  1988 ----------------------------------
  1989 
  1990 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1991 
  1992 * several changes of automated proof tools;
  1993 
  1994 * HOL: major changes to the inductive and datatype packages, including
  1995 some minor incompatibilities of theory syntax;
  1996 
  1997 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1998 called `inj_on';
  1999 
  2000 * HOL: removed duplicate thms in Arith:
  2001   less_imp_add_less  should be replaced by  trans_less_add1
  2002   le_imp_add_le      should be replaced by  trans_le_add1
  2003 
  2004 * HOL: unary minus is now overloaded (new type constraints may be
  2005 required);
  2006 
  2007 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2008 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2009 now taken as an integer constant.
  2010 
  2011 * Pure: ML function 'theory_of' renamed to 'theory';
  2012 
  2013 
  2014 *** Proof tools ***
  2015 
  2016 * Simplifier:
  2017   1. Asm_full_simp_tac is now more aggressive.
  2018      1. It will sometimes reorient premises if that increases their power to
  2019         simplify.
  2020      2. It does no longer proceed strictly from left to right but may also
  2021         rotate premises to achieve further simplification.
  2022      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2023      old Asm_full_simp_tac in that it does not rotate premises.
  2024   2. The simplifier now knows a little bit about nat-arithmetic.
  2025 
  2026 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2027 allows for selected deletion of wrappers, by introduction of names for
  2028 wrapper functionals.  This implies that addbefore, addSbefore,
  2029 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2030 and that adding two tactics with the same name overwrites the first
  2031 one (emitting a warning).
  2032   type wrapper = (int -> tactic) -> (int -> tactic)
  2033   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2034   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2035   delWrapper, delSWrapper: claset *  string            -> claset
  2036   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2037 
  2038 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2039 semantics; addbefore now affects only the unsafe part of step_tac
  2040 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2041 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2042 by Force_tac;
  2043 
  2044 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2045 compWrapper; added safe wrapper (and access functions for it);
  2046 
  2047 * HOL/split_all_tac is now much faster and fails if there is nothing
  2048 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2049 and the names of the automatically generated variables have changed.
  2050 split_all_tac has moved within claset() from unsafe wrappers to safe
  2051 wrappers, which means that !!-bound variables are split much more
  2052 aggressively, and safe_tac and clarify_tac now split such variables.
  2053 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2054 Note: the same holds for record_split_tac, which does the job of
  2055 split_all_tac for record fields.
  2056 
  2057 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2058 permanently to the default simpset using Addsplits just like
  2059 Addsimps. They can be removed via Delsplits just like
  2060 Delsimps. Lower-case versions are also available.
  2061 
  2062 * HOL/Simplifier: The rule split_if is now part of the default
  2063 simpset. This means that the simplifier will eliminate all occurrences
  2064 of if-then-else in the conclusion of a goal. To prevent this, you can
  2065 either remove split_if completely from the default simpset by
  2066 `Delsplits [split_if]' or remove it in a specific call of the
  2067 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2068 other case splitting rules to/from the default simpset: every datatype
  2069 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2070 t is the name of the datatype).
  2071 
  2072 * Classical reasoner / Simplifier combination: new force_tac (and
  2073 derivatives Force_tac, force) combines rewriting and classical
  2074 reasoning (and whatever other tools) similarly to auto_tac, but is
  2075 aimed to solve the given subgoal completely.
  2076 
  2077 
  2078 *** General ***
  2079 
  2080 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2081 and `goalw': the theory is no longer needed as an explicit argument -
  2082 the current theory context is used; assumptions are no longer returned
  2083 at the ML-level unless one of them starts with ==> or !!; it is
  2084 recommended to convert to these new commands using isatool fixgoal
  2085 (backup your sources first!);
  2086 
  2087 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2088 the current theory context, and 'theory' to lookup stored theories;
  2089 
  2090 * new theory section 'locale' for declaring constants, assumptions and
  2091 definitions that have local scope;
  2092 
  2093 * new theory section 'nonterminals' for purely syntactic types;
  2094 
  2095 * new theory section 'setup' for generic ML setup functions
  2096 (e.g. package initialization);
  2097 
  2098 * the distribution now includes Isabelle icons: see
  2099 lib/logo/isabelle-{small,tiny}.xpm;
  2100 
  2101 * isatool install - install binaries with absolute references to
  2102 ISABELLE_HOME/bin;
  2103 
  2104 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2105 
  2106 * print mode 'emacs' reserved for Isamode;
  2107 
  2108 * support multiple print (ast) translations per constant name;
  2109 
  2110 * theorems involving oracles are now printed with a suffixed [!];
  2111 
  2112 
  2113 *** HOL ***
  2114 
  2115 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2116 
  2117 * HOL/inductive package reorganized and improved: now supports mutual
  2118 definitions such as
  2119 
  2120   inductive EVEN ODD
  2121     intrs
  2122       null "0 : EVEN"
  2123       oddI "n : EVEN ==> Suc n : ODD"
  2124       evenI "n : ODD ==> Suc n : EVEN"
  2125 
  2126 new theorem list "elims" contains an elimination rule for each of the
  2127 recursive sets; inductive definitions now handle disjunctive premises
  2128 correctly (also ZF);
  2129 
  2130 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2131 "mutual_induct" no longer exists - the induction rule is always
  2132 contained in "induct";
  2133 
  2134 
  2135 * HOL/datatype package re-implemented and greatly improved: now
  2136 supports mutually recursive datatypes such as
  2137 
  2138   datatype
  2139     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2140             | SUM ('a aexp) ('a aexp)
  2141             | DIFF ('a aexp) ('a aexp)
  2142             | NUM 'a
  2143   and
  2144     'a bexp = LESS ('a aexp) ('a aexp)
  2145             | AND ('a bexp) ('a bexp)
  2146             | OR ('a bexp) ('a bexp)
  2147 
  2148 as well as indirectly recursive datatypes such as
  2149 
  2150   datatype
  2151     ('a, 'b) term = Var 'a
  2152                   | App 'b ((('a, 'b) term) list)
  2153 
  2154 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2155 induction on mutually / indirectly recursive datatypes.
  2156 
  2157 Primrec equations are now stored in theory and can be accessed via
  2158 <function_name>.simps.
  2159 
  2160 INCOMPATIBILITIES:
  2161 
  2162   - Theories using datatypes must now have theory Datatype as an
  2163     ancestor.
  2164   - The specific <typename>.induct_tac no longer exists - use the
  2165     generic induct_tac instead.
  2166   - natE has been renamed to nat.exhaust - use exhaust_tac
  2167     instead of res_inst_tac ... natE. Note that the variable
  2168     names in nat.exhaust differ from the names in natE, this
  2169     may cause some "fragile" proofs to fail.
  2170   - The theorems split_<typename>_case and split_<typename>_case_asm
  2171     have been renamed to <typename>.split and <typename>.split_asm.
  2172   - Since default sorts of type variables are now handled correctly,
  2173     some datatype definitions may have to be annotated with explicit
  2174     sort constraints.
  2175   - Primrec definitions no longer require function name and type
  2176     of recursive argument.
  2177 
  2178 Consider using isatool fixdatatype to adapt your theories and proof
  2179 scripts to the new package (backup your sources first!).
  2180 
  2181 
  2182 * HOL/record package: considerably improved implementation; now
  2183 includes concrete syntax for record types, terms, updates; theorems
  2184 for surjective pairing and splitting !!-bound record variables; proof
  2185 support is as follows:
  2186 
  2187   1) standard conversions (selectors or updates applied to record
  2188 constructor terms) are part of the standard simpset;
  2189 
  2190   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2191 made part of standard simpset and claset via addIffs;
  2192 
  2193   3) a tactic for record field splitting (record_split_tac) is part of
  2194 the standard claset (addSWrapper);
  2195 
  2196 To get a better idea about these rules you may retrieve them via
  2197 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2198 the name of your record type.
  2199 
  2200 The split tactic 3) conceptually simplifies by the following rule:
  2201 
  2202   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2203 
  2204 Thus any record variable that is bound by meta-all will automatically
  2205 blow up into some record constructor term, consequently the
  2206 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2207 solve record problems automatically.
  2208 
  2209 
  2210 * reorganized the main HOL image: HOL/Integ and String loaded by
  2211 default; theory Main includes everything;
  2212 
  2213 * automatic simplification of integer sums and comparisons, using cancellation;
  2214 
  2215 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2216 
  2217 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2218 
  2219 * many new identities for unions, intersections, set difference, etc.;
  2220 
  2221 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2222 called split_if, split_split, split_sum_case and split_nat_case (to go
  2223 with add/delsplits);
  2224 
  2225 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2226 (?x::unit) = (); this is made part of the default simpset, which COULD
  2227 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2228 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2229 unit_abs_eta_conv is added in order to counter the effect of
  2230 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2231 %u.f();
  2232 
  2233 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2234 makes more sense);
  2235 
  2236 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2237   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2238   disjointness reasoning but breaking a few old proofs.
  2239 
  2240 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2241 to 'converse' from 'inverse' (for compatibility with ZF and some
  2242 literature);
  2243 
  2244 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2245 the well-founded relation;
  2246 
  2247 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2248     Compl A.  The "Compl" syntax remains available as input syntax for this
  2249     release ONLY.
  2250 
  2251 * HOL/Update: new theory of function updates:
  2252     f(a:=b) == %x. if x=a then b else f x
  2253 may also be iterated as in f(a:=b,c:=d,...);
  2254 
  2255 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2256 
  2257 * HOL/List:
  2258   - new function list_update written xs[i:=v] that updates the i-th
  2259     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2260   - new function `upt' written [i..j(] which generates the list
  2261     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2262     bound write [i..j], which is a shorthand for [i..j+1(].
  2263   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2264 
  2265 * HOL/Arith:
  2266   - removed 'pred' (predecessor) function;
  2267   - generalized some theorems about n-1;
  2268   - many new laws about "div" and "mod";
  2269   - new laws about greatest common divisors (see theory ex/Primes);
  2270 
  2271 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2272 instead of "inverse";
  2273 
  2274 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2275   of the multiset ordering;
  2276 
  2277 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2278   (not included by default);
  2279 
  2280 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2281 
  2282 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2283   programs, i.e. different program variables may have different types.
  2284 
  2285 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2286   [previously, this check worked only if the rewrite rule was unconditional]
  2287   Now rew can involve either definitions or equalities (either == or =).
  2288 
  2289 
  2290 *** ZF ***
  2291 
  2292 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2293   only the theorems proved on ZF.ML;
  2294 
  2295 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2296   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2297   disjointness reasoning but breaking a few old proofs.
  2298 
  2299 * ZF/Update: new theory of function updates
  2300     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2301   may also be iterated as in f(a:=b,c:=d,...);
  2302 
  2303 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2304 
  2305 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2306   [previously, this check worked only if the rewrite rule was unconditional]
  2307   Now rew can involve either definitions or equalities (either == or =).
  2308 
  2309 * case_tac provided for compatibility with HOL
  2310     (like the old excluded_middle_tac, but with subgoals swapped)
  2311 
  2312 
  2313 *** Internal programming interfaces ***
  2314 
  2315 * Pure: several new basic modules made available for general use, see
  2316 also src/Pure/README;
  2317 
  2318 * improved the theory data mechanism to support encapsulation (data
  2319 kind name replaced by private Object.kind, acting as authorization
  2320 key); new type-safe user interface via functor TheoryDataFun; generic
  2321 print_data function becomes basically useless;
  2322 
  2323 * removed global_names compatibility flag -- all theory declarations
  2324 are qualified by default;
  2325 
  2326 * module Pure/Syntax now offers quote / antiquote translation
  2327 functions (useful for Hoare logic etc. with implicit dependencies);
  2328 see HOL/ex/Antiquote for an example use;
  2329 
  2330 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2331 cterm -> thm;
  2332 
  2333 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2334 subgoal;
  2335 
  2336 * Display.print_goals function moved to Locale.print_goals;
  2337 
  2338 * standard print function for goals supports current_goals_markers
  2339 variable for marking begin of proof, end of proof, start of goal; the
  2340 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2341 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2342 for example;
  2343 
  2344 
  2345 
  2346 New in Isabelle98 (January 1998)
  2347 --------------------------------
  2348 
  2349 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2350 
  2351 * changed lexical syntax of terms / types: dots made part of long
  2352 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2353 
  2354 * simpset (and claset) reference variable replaced by functions
  2355 simpset / simpset_ref;
  2356 
  2357 * no longer supports theory aliases (via merge) and non-trivial
  2358 implicit merge of thms' signatures;
  2359 
  2360 * most internal names of constants changed due to qualified names;
  2361 
  2362 * changed Pure/Sequence interface (see Pure/seq.ML);
  2363 
  2364 
  2365 *** General Changes ***
  2366 
  2367 * hierachically structured name spaces (for consts, types, axms, thms
  2368 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2369 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2370 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2371 long_names for fully qualified output names; NOTE: ML programs
  2372 (special tactics, packages etc.) referring to internal names may have
  2373 to be adapted to cope with fully qualified names; in case of severe
  2374 backward campatibility problems try setting 'global_names' at compile
  2375 time to have enrything declared within a flat name space; one may also
  2376 fine tune name declarations in theories via the 'global' and 'local'
  2377 section;
  2378 
  2379 * reimplemented the implicit simpset and claset using the new anytype
  2380 data filed in signatures; references simpset:simpset ref etc. are
  2381 replaced by functions simpset:unit->simpset and
  2382 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2383 to patch your ML files accordingly;
  2384 
  2385 * HTML output now includes theory graph data for display with Java
  2386 applet or isatool browser; data generated automatically via isatool
  2387 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2388 
  2389 * defs may now be conditional; improved rewrite_goals_tac to handle
  2390 conditional equations;
  2391 
  2392 * defs now admits additional type arguments, using TYPE('a) syntax;
  2393 
  2394 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2395 creates a new theory node; implicit merge of thms' signatures is
  2396 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2397 transfer:theory->thm->thm in (rare) cases;
  2398 
  2399 * improved handling of draft signatures / theories; draft thms (and
  2400 ctyps, cterms) are automatically promoted to real ones;
  2401 
  2402 * slightly changed interfaces for oracles: admit many per theory, named
  2403 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2404 
  2405 * print_goals: optional output of const types (set show_consts and
  2406 show_types);
  2407 
  2408 * improved output of warnings (###) and errors (***);
  2409 
  2410 * subgoal_tac displays a warning if the new subgoal has type variables;
  2411 
  2412 * removed old README and Makefiles;
  2413 
  2414 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2415 
  2416 * removed obsolete init_pps and init_database;
  2417 
  2418 * deleted the obsolete tactical STATE, which was declared by
  2419     fun STATE tacfun st = tacfun st st;
  2420 
  2421 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2422 (which abbreviates $HOME);
  2423 
  2424 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2425 use isatool fixseq to adapt your ML programs (this works for fully
  2426 qualified references to the Sequence structure only!);
  2427 
  2428 * use_thy no longer requires writable current directory; it always
  2429 reloads .ML *and* .thy file, if either one is out of date;
  2430 
  2431 
  2432 *** Classical Reasoner ***
  2433 
  2434 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2435 tactics that use classical reasoning to simplify a subgoal without
  2436 splitting it into several subgoals;
  2437 
  2438 * Safe_tac: like safe_tac but uses the default claset;
  2439 
  2440 
  2441 *** Simplifier ***
  2442 
  2443 * added simplification meta rules:
  2444     (asm_)(full_)simplify: simpset -> thm -> thm;
  2445 
  2446 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2447 logics (again);
  2448 
  2449 * added prems argument to simplification procedures;
  2450 
  2451 * HOL, FOL, ZF: added infix function `addsplits':
  2452   instead of `<simpset> setloop (split_tac <thms>)'
  2453   you can simply write `<simpset> addsplits <thms>'
  2454 
  2455 
  2456 *** Syntax ***
  2457 
  2458 * TYPE('a) syntax for type reflection terms;
  2459 
  2460 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2461 
  2462 * pretty printer: changed order of mixfix annotation preference (again!);
  2463 
  2464 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2465 
  2466 
  2467 *** HOL ***
  2468 
  2469 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2470   with `addloop' of the simplifier to faciliate case splitting in premises.
  2471 
  2472 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2473 
  2474 * HOL/Auth: new protocol proofs including some for the Internet
  2475   protocol TLS;
  2476 
  2477 * HOL/Map: new theory of `maps' a la VDM;
  2478 
  2479 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2480 cancelling out common nat summands from =, <, <= (in)equalities, or
  2481 differences; simplification procedures nat_cancel_factor for
  2482 cancelling common factor from =, <, <= (in)equalities over natural
  2483 sums; nat_cancel contains both kinds of procedures, it is installed by
  2484 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2485 
  2486 * HOL/simplifier: terms of the form
  2487   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2488   are rewritten to
  2489   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2490   and those of the form
  2491   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2492   are rewritten to
  2493   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2494 
  2495 * HOL/datatype
  2496   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2497 
  2498   P(t_case f1 ... fn x) =
  2499      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2500         ...
  2501        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2502      )
  2503 
  2504   and a theorem `split_t_case_asm' of the form
  2505 
  2506   P(t_case f1 ... fn x) =
  2507     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2508         ...
  2509        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2510      )
  2511   which can be added to a simpset via `addsplits'. The existing theorems
  2512   expand_list_case and expand_option_case have been renamed to
  2513   split_list_case and split_option_case.
  2514 
  2515 * HOL/Arithmetic:
  2516   - `pred n' is automatically converted to `n-1'.
  2517     Users are strongly encouraged not to use `pred' any longer,
  2518     because it will disappear altogether at some point.
  2519   - Users are strongly encouraged to write "0 < n" rather than
  2520     "n ~= 0". Theorems and proof tools have been modified towards this
  2521     `standard'.
  2522 
  2523 * HOL/Lists:
  2524   the function "set_of_list" has been renamed "set" (and its theorems too);
  2525   the function "nth" now takes its arguments in the reverse order and
  2526   has acquired the infix notation "!" as in "xs!n".
  2527 
  2528 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2529 
  2530 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2531   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2532 
  2533 * HOL/record: extensible records with schematic structural subtyping
  2534 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2535 still lacks various theorems and concrete record syntax;
  2536 
  2537 
  2538 *** HOLCF ***
  2539 
  2540 * removed "axioms" and "generated by" sections;
  2541 
  2542 * replaced "ops" section by extended "consts" section, which is capable of
  2543   handling the continuous function space "->" directly;
  2544 
  2545 * domain package:
  2546   . proves theorems immediately and stores them in the theory,
  2547   . creates hierachical name space,
  2548   . now uses normal mixfix annotations (instead of cinfix...),
  2549   . minor changes to some names and values (for consistency),
  2550   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2551   . separator between mutual domain defs: changed "," to "and",
  2552   . improved handling of sort constraints;  now they have to
  2553     appear on the left-hand side of the equations only;
  2554 
  2555 * fixed LAM <x,y,zs>.b syntax;
  2556 
  2557 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2558 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2559 
  2560 
  2561 *** FOL and ZF ***
  2562 
  2563 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2564   with `addloop' of the simplifier to faciliate case splitting in premises.
  2565 
  2566 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2567 in HOL, they strip ALL and --> from proved theorems;
  2568 
  2569 
  2570 
  2571 New in Isabelle94-8 (May 1997)
  2572 ------------------------------
  2573 
  2574 *** General Changes ***
  2575 
  2576 * new utilities to build / run / maintain Isabelle etc. (in parts
  2577 still somewhat experimental); old Makefiles etc. still functional;
  2578 
  2579 * new 'Isabelle System Manual';
  2580 
  2581 * INSTALL text, together with ./configure and ./build scripts;
  2582 
  2583 * reimplemented type inference for greater efficiency, better error
  2584 messages and clean internal interface;
  2585 
  2586 * prlim command for dealing with lots of subgoals (an easier way of
  2587 setting goals_limit);
  2588 
  2589 
  2590 *** Syntax ***
  2591 
  2592 * supports alternative (named) syntax tables (parser and pretty
  2593 printer); internal interface is provided by add_modesyntax(_i);
  2594 
  2595 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2596 be used in conjunction with the Isabelle symbol font; uses the
  2597 "symbols" syntax table;
  2598 
  2599 * added token_translation interface (may translate name tokens in
  2600 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2601 the current print_mode); IMPORTANT: user print translation functions
  2602 are responsible for marking newly introduced bounds
  2603 (Syntax.mark_boundT);
  2604 
  2605 * token translations for modes "xterm" and "xterm_color" that display
  2606 names in bold, underline etc. or colors (which requires a color
  2607 version of xterm);
  2608 
  2609 * infixes may now be declared with names independent of their syntax;
  2610 
  2611 * added typed_print_translation (like print_translation, but may
  2612 access type of constant);
  2613 
  2614 
  2615 *** Classical Reasoner ***
  2616 
  2617 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2618 some limitations.  Blast_tac...
  2619   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2620   + ignores elimination rules that don't have the correct format
  2621         (the conclusion MUST be a formula variable)
  2622   + ignores types, which can make HOL proofs fail
  2623   + rules must not require higher-order unification, e.g. apply_type in ZF
  2624     [message "Function Var's argument not a bound variable" relates to this]
  2625   + its proof strategy is more general but can actually be slower
  2626 
  2627 * substitution with equality assumptions no longer permutes other
  2628 assumptions;
  2629 
  2630 * minor changes in semantics of addafter (now called addaltern); renamed
  2631 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2632 (and access functions for it);
  2633 
  2634 * improved combination of classical reasoner and simplifier:
  2635   + functions for handling clasimpsets
  2636   + improvement of addss: now the simplifier is called _after_ the
  2637     safe steps.
  2638   + safe variant of addss called addSss: uses safe simplifications
  2639     _during_ the safe steps. It is more complete as it allows multiple
  2640     instantiations of unknowns (e.g. with slow_tac).
  2641 
  2642 *** Simplifier ***
  2643 
  2644 * added interface for simplification procedures (functions that
  2645 produce *proven* rewrite rules on the fly, depending on current
  2646 redex);
  2647 
  2648 * ordering on terms as parameter (used for ordered rewriting);
  2649 
  2650 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2651 
  2652 * the solver is now split into a safe and an unsafe part.
  2653 This should be invisible for the normal user, except that the
  2654 functions setsolver and addsolver have been renamed to setSolver and
  2655 addSolver; added safe_asm_full_simp_tac;
  2656 
  2657 
  2658 *** HOL ***
  2659 
  2660 * a generic induction tactic `induct_tac' which works for all datatypes and
  2661 also for type `nat';
  2662 
  2663 * a generic case distinction tactic `exhaust_tac' which works for all
  2664 datatypes and also for type `nat';
  2665 
  2666 * each datatype comes with a function `size';
  2667 
  2668 * patterns in case expressions allow tuple patterns as arguments to
  2669 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2670 
  2671 * primrec now also works with type nat;
  2672 
  2673 * recdef: a new declaration form, allows general recursive functions to be
  2674 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2675 
  2676 * the constant for negation has been renamed from "not" to "Not" to
  2677 harmonize with FOL, ZF, LK, etc.;
  2678 
  2679 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2680 infinite lists;
  2681 
  2682 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2683 
  2684 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2685 problems in commutative rings, using axiomatic type classes for + and *;
  2686 
  2687 * more examples in HOL/MiniML and HOL/Auth;
  2688 
  2689 * more default rewrite rules for quantifiers, union/intersection;
  2690 
  2691 * a new constant `arbitrary == @x.False';
  2692 
  2693 * HOLCF/IOA replaces old HOL/IOA;
  2694 
  2695 * HOLCF changes: derived all rules and arities
  2696   + axiomatic type classes instead of classes
  2697   + typedef instead of faking type definitions
  2698   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2699   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2700   + eliminated the types void, one, tr
  2701   + use unit lift and bool lift (with translations) instead of one and tr
  2702   + eliminated blift from Lift3.thy (use Def instead of blift)
  2703   all eliminated rules are derived as theorems --> no visible changes ;
  2704 
  2705 
  2706 *** ZF ***
  2707 
  2708 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2709 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2710 as ZF_cs addSIs [equalityI];
  2711 
  2712 
  2713 
  2714 New in Isabelle94-7 (November 96)
  2715 ---------------------------------
  2716 
  2717 * allowing negative levels (as offsets) in prlev and choplev;
  2718 
  2719 * super-linear speedup for large simplifications;
  2720 
  2721 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2722 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2723 FAIL); can suppress it using the command Delsimps (ex_simps @
  2724 all_simps); De Morgan laws are also now included, by default;
  2725 
  2726 * improved printing of ==>  :  ~:
  2727 
  2728 * new object-logic "Sequents" adds linear logic, while replacing LK
  2729 and Modal (thanks to Sara Kalvala);
  2730 
  2731 * HOL/Auth: correctness proofs for authentication protocols;
  2732 
  2733 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2734 examples on HOL/Auth);
  2735 
  2736 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2737 the rewriter and classical reasoner simultaneously;
  2738 
  2739 * function uresult no longer returns theorems in "standard" format;
  2740 regain previous version by: val uresult = standard o uresult;
  2741 
  2742 
  2743 
  2744 New in Isabelle94-6
  2745 -------------------
  2746 
  2747 * oracles -- these establish an interface between Isabelle and trusted
  2748 external reasoners, which may deliver results as theorems;
  2749 
  2750 * proof objects (in particular record all uses of oracles);
  2751 
  2752 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2753 
  2754 * "constdefs" section in theory files;
  2755 
  2756 * "primrec" section (HOL) no longer requires names;
  2757 
  2758 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2759 
  2760 
  2761 
  2762 New in Isabelle94-5
  2763 -------------------
  2764 
  2765 * reduced space requirements;
  2766 
  2767 * automatic HTML generation from theories;
  2768 
  2769 * theory files no longer require "..." (quotes) around most types;
  2770 
  2771 * new examples, including two proofs of the Church-Rosser theorem;
  2772 
  2773 * non-curried (1994) version of HOL is no longer distributed;
  2774 
  2775 
  2776 
  2777 New in Isabelle94-4
  2778 -------------------
  2779 
  2780 * greatly reduced space requirements;
  2781 
  2782 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2783 
  2784 * searchable theorem database (see the section "Retrieving theorems" on
  2785 page 8 of the Reference Manual);
  2786 
  2787 * new examples, including Grabczewski's monumental case study of the
  2788 Axiom of Choice;
  2789 
  2790 * The previous version of HOL renamed to Old_HOL;
  2791 
  2792 * The new version of HOL (previously called CHOL) uses a curried syntax
  2793 for functions.  Application looks like f a b instead of f(a,b);
  2794 
  2795 * Mutually recursive inductive definitions finally work in HOL;
  2796 
  2797 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2798 translates to the operator "split";
  2799 
  2800 
  2801 
  2802 New in Isabelle94-3
  2803 -------------------
  2804 
  2805 * new infix operator, addss, allowing the classical reasoner to
  2806 perform simplification at each step of its search.  Example:
  2807         fast_tac (cs addss ss)
  2808 
  2809 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2810 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2811 look like (a,b) instead of <a,b>;
  2812 
  2813 * PLEASE NOTE: CHOL will eventually replace HOL!
  2814 
  2815 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2816 It translates to the operator "split".  A new theory of integers is available;
  2817 
  2818 * In ZF, integer numerals now denote two's-complement binary integers.
  2819 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2820 
  2821 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2822 of the Axiom of Choice;
  2823 
  2824 
  2825 
  2826 New in Isabelle94-2
  2827 -------------------
  2828 
  2829 * Significantly faster resolution;
  2830 
  2831 * the different sections in a .thy file can now be mixed and repeated
  2832 freely;
  2833 
  2834 * Database of theorems for FOL, HOL and ZF.  New
  2835 commands including qed, qed_goal and bind_thm store theorems in the database.
  2836 
  2837 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2838 a given theory (thms_of), or find out what theory a theorem was proved in
  2839 (theory_of_thm);
  2840 
  2841 * Bugs fixed in the inductive definition and datatype packages;
  2842 
  2843 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2844 and HOL_dup_cs obsolete;
  2845 
  2846 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2847 have been removed;
  2848 
  2849 * Simpler definition of function space in ZF;
  2850 
  2851 * new results about cardinal and ordinal arithmetic in ZF;
  2852 
  2853 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2854 types;
  2855 
  2856 
  2857 $Id$