NEWS
author nipkow
Tue Oct 12 16:59:56 2004 +0200 (2004-10-12)
changeset 15242 1a4b471b1afa
parent 15206 09d78ec709c7
child 15277 eb649b6dbf15
permissions -rw-r--r--
*** empty log message ***
     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 * Provers/blast.ML:  new reference depth_limit to make blast's depth
    29   limit (previously hard-coded with a value of 20) user-definable.
    30 
    31 * Pure: considerably improved version of 'constdefs' command.  Now
    32   performs automatic type-inference of declared constants; additional
    33   support for local structure declarations (cf. locales and HOL
    34   records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    35   to observe strictly sequential dependencies of definitions within a
    36   single 'constdefs' section; moreover, the declared name needs to be
    37   an identifier.  If all fails, consider to fall back on 'consts' and
    38   'defs' separately.
    39 
    40 * Pure: improved indexed syntax and implicit structures.  First of
    41   all, indexed syntax provides a notational device for subscripted
    42   application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    43   expressions.  Secondly, in a local context with structure
    44   declarations, number indexes \<^sub>n or the empty index (default
    45   number 1) refer to a certain fixed variable implicitly; option
    46   show_structs controls printing of implicit structures.  Typical
    47   applications of these concepts involve record types and locales.
    48 
    49 * Pure: clear separation of logical types and nonterminals, where the
    50   latter may only occur in 'syntax' specifications or type
    51   abbreviations.  Before that distinction was only partially
    52   implemented via type class "logic" vs. "{}".  Potential
    53   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
    54   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
    55   specifications may require further adaption (e.g. Cube/Base.thy).
    56 
    57 * Pure: removed obsolete type class "logic", use the top sort {}
    58   instead.  Note that non-logical types should be declared as
    59   'nonterminals' rather than 'types'.  INCOMPATIBILITY for new
    60   object-logic specifications.
    61 
    62 * Pure: print_tac now outputs the goal through the trace channel.
    63 
    64 * Pure: reference Namespace.unique_names included.  If true the
    65   (shortest) namespace-prefix is printed to disambiguate conflicts (as
    66   yet). If false the first entry wins (as during parsing). Default
    67   value is true.
    68 
    69 * Pure: tuned internal renaming of symbolic identifiers -- attach
    70   primes instead of base 26 numbers.
    71 
    72 * Pure/Syntax: inner syntax includes (*(*nested*) comments*).
    73 
    74 * Pure/Syntax: pretty pinter now supports unbreakable blocks,
    75   specified in mixfix annotations as "(00...)".
    76 
    77 * Pure/Syntax: 'advanced' translation functions (parse_translation
    78   etc.) may depend on the signature of the theory context being
    79   presently used for parsing/printing, see also isar-ref manual.
    80 
    81 * Pure/Simplifier: simplification procedures may now take the current
    82   simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
    83   interface), which is very useful for calling the Simplifier
    84   recursively.  Minor INCOMPATIBILITY: the 'prems' argument of
    85   simprocs is gone -- use prems_of_ss on the simpset instead.
    86   Moreover, the low-level mk_simproc no longer applies Logic.varify
    87   internally, to allow for use in a context of fixed variables.
    88 
    89 * Provers: Simplifier and Classical Reasoner now support proof context
    90   dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
    91   components are stored in the theory and patched into the
    92   simpset/claset when used in an Isar proof context.  Context
    93   dependent components are maintained by the following theory
    94   operations:
    95 
    96     Simplifier.add_context_simprocs
    97     Simplifier.del_context_simprocs
    98     Simplifier.set_context_subgoaler
    99     Simplifier.reset_context_subgoaler
   100     Simplifier.add_context_looper
   101     Simplifier.del_context_looper
   102     Simplifier.add_context_unsafe_solver
   103     Simplifier.add_context_safe_solver
   104 
   105     Classical.add_context_safe_wrapper
   106     Classical.del_context_safe_wrapper
   107     Classical.add_context_unsafe_wrapper
   108     Classical.del_context_unsafe_wrapper
   109 
   110   IMPORTANT NOTE: proof tools (methods etc.) need to use
   111   local_simpset_of and local_claset_of to instead of the primitive
   112   Simplifier.get_local_simpset and Classical.get_local_claset,
   113   respectively, in order to see the context dependent fields!
   114 
   115 * Document preparation: antiquotations now provide the option
   116   'locale=NAME' to specify an alternative context used for evaluating
   117   and printing the subsequent argument, as in @{thm [locale=LC]
   118   fold_commute}, for example.
   119 
   120 * Document preparation: commands 'display_drafts' and 'print_drafts'
   121   perform simple output of raw sources.  Only those symbols that do
   122   not require additional LaTeX packages (depending on comments in
   123   isabellesym.sty) are displayed properly, everything else is left
   124   verbatim.  We use isatool display and isatool print as front ends;
   125   these are subject to the DVI_VIEWER and PRINT_COMMAND settings,
   126   respectively.
   127 
   128 * ML: output via the Isabelle channels of writeln/warning/error
   129   etc. is now passed through Output.output, with a hook for arbitrary
   130   transformations depending on the print_mode (cf. Output.add_mode --
   131   the first active mode that provides a output function wins).
   132   Already formatted output may be embedded into further text via
   133   Output.raw; the result of Pretty.string_of/str_of and derived
   134   functions (string_of_term/cterm/thm etc.) is already marked raw to
   135   accommodate easy composition of diagnostic messages etc.
   136   Programmers rarely need to care about Output.output or Output.raw at
   137   all, with some notable exceptions: Output.output is required when
   138   bypassing the standard channels (writeln etc.), or in token
   139   translations to produce properly formatted results; Output.raw is
   140   required when capturing already output material that will eventually
   141   be presented to the user a second time.  For the default print mode,
   142   both Output.output and Output.raw have no effect.
   143 
   144 
   145 *** Isar ***
   146 
   147 * Locales:
   148   - "includes" disallowed in declaration of named locales (command "locale").
   149   - Fixed parameter management in theorem generation for goals with "includes".
   150     INCOMPATIBILITY: rarely, the generated theorem statement is different.
   151  
   152 *** HOL ***
   153 
   154 * Datatype induction via method `induct' now preserves the name of the
   155   induction variable. For example, when proving P(xs::'a list) by induction
   156   on xs, the induction step is now P(xs) ==> P(a#xs) rather than
   157   P(list) ==> P(a#list) as previously.
   158 
   159 * HOL/record: reimplementation of records. Improved scalability for
   160   records with many fields, avoiding performance problems for type
   161   inference. Records are no longer composed of nested field types, but
   162   of nested extension types. Therefore the record type only grows
   163   linear in the number of extensions and not in the number of fields.
   164   The top-level (users) view on records is preserved.  Potential
   165   INCOMPATIBILITY only in strange cases, where the theory depends on
   166   the old record representation. The type generated for a record is
   167   called <record_name>_ext_type.
   168 
   169 * HOL/record: Reference record_quick_and_dirty_sensitive can be
   170   enabled to skip the proofs triggered by a record definition or a
   171   simproc (if quick_and_dirty is enabled). Definitions of large
   172   records can take quite long.
   173 
   174 * HOL/record: "record_upd_simproc" for simplification of multiple
   175   record updates enabled by default.  Moreover, trivial updates are
   176   also removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   177   occasionally, since simplification is more powerful by default.
   178 
   179 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
   180 
   181   syntax (epsilon)
   182     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   183 
   184   The symbol \<some> is displayed as the alternative epsilon of LaTeX
   185   and x-symbol; use option '-m epsilon' to get it actually printed.
   186   Moreover, the mathematically important symbolic identifier
   187   \<epsilon> becomes available as variable, constant etc.
   188 
   189 * HOL/SetInterval: The syntax for open intervals has changed:
   190 
   191   Old         New
   192   {..n(}   -> {..<n}
   193   {)n..}   -> {n<..}
   194   {m..n(}  -> {m..<n}
   195   {)m..n}  -> {m<..n}
   196   {)m..n(} -> {m<..<n}
   197 
   198   The old syntax is still supported but will disappear in the future.
   199   For conversion use the following emacs search and replace patterns:
   200 
   201   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   202   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   203 
   204   They are not perfect but work quite well.
   205 
   206 * HOL: The syntax for 'setsum', summation over finite sets, has changed:
   207 
   208   The syntax for 'setsum (%x. e) A' used to be '\<Sum>x:A. e'
   209   and is now either 'SUM x:A. e' or '\<Sum>x\<in>A. e'.
   210 
   211   There is new syntax for summation over finite sets:
   212 
   213   '\<Sum>x | P. e'    is the same as  'setsum (%x. e) {x. P}'
   214   '\<Sum>x=a..b. e'   is the same as  'setsum (%x. e) {a..b}'
   215   '\<Sum>x=a..<b. e'  is the same as  'setsum (%x. e) {a..<b}'
   216   '\<Sum>x<k. e'      is the same as  'setsum (%x. e) {..<k}'
   217 
   218   Function 'Summation' over nat is gone, its syntax '\<Sum>i<k. e'
   219   now translates into 'setsum' as above.
   220 
   221 * HOL/Simplifier:
   222 
   223   - Is now set up to reason about transitivity chains involving "trancl"
   224   (r^+) and "rtrancl" (r^*) by setting up tactics provided by
   225   Provers/trancl.ML as additional solvers.  INCOMPATIBILITY: old proofs break
   226   occasionally as simplification may now solve more goals than previously.
   227 
   228   - Converts x <= y into x = y if assumption y <= x is present.  Works for
   229   all partial orders (class "order"), in particular numbers and sets. For
   230   linear orders (e.g. numbers) it treats ~ x < y just like y <= x.
   231 
   232 * HOL: new 'isatool dimacs2hol' to convert files in DIMACS CNF format
   233   (containing Boolean satisfiability problems) into Isabelle/HOL theories.
   234 
   235 
   236 *** HOLCF ***
   237 
   238 * HOLCF: discontinued special version of 'constdefs' (which used to
   239   support continuous functions) in favor of the general Pure one with
   240   full type-inference.
   241 
   242 
   243 *** ZF ***
   244 
   245 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the
   246   First Isomorphism Theorem (on quotienting by the kernel of a
   247   homomorphism).
   248 
   249 * ZF/Simplifier: install second copy of type solver that actually
   250   makes use of TC rules declared to Isar proof contexts (or locales);
   251   the old version is still required for ML proof scripts.
   252 
   253 
   254 
   255 New in Isabelle2004 (April 2004)
   256 --------------------------------
   257 
   258 *** General ***
   259 
   260 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   261   Replaces linorder.ML.
   262 
   263 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   264   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   265   (\<a>...\<z>), are now considered normal letters, and can therefore
   266   be used anywhere where an ASCII letter (a...zA...Z) has until
   267   now. COMPATIBILITY: This obviously changes the parsing of some
   268   terms, especially where a symbol has been used as a binder, say
   269   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   270   as an identifier.  Fix it by inserting a space around former
   271   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   272   existing theory and ML files.
   273 
   274 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   275 
   276 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   277   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   278   a normal (but invisible) letter. For multiple letter subscripts repeat
   279   \<^isub> like this: x\<^isub>1\<^isub>2.
   280 
   281 * Pure: There are now sub-/superscripts that can span more than one
   282   character. Text between \<^bsub> and \<^esub> is set in subscript in
   283   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   284   superscript. The new control characters are not identifier parts.
   285 
   286 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   287   content of "..." to the latex file instead of \isacntrl... . The "..."
   288   may consist of any printable characters excluding the end bracket >.
   289 
   290 * Pure: Using new Isar command "finalconsts" (or the ML functions
   291   Theory.add_finals or Theory.add_finals_i) it is now possible to
   292   declare constants "final", which prevents their being given a definition
   293   later.  It is useful for constants whose behaviour is fixed axiomatically
   294   rather than definitionally, such as the meta-logic connectives.
   295 
   296 * Pure: 'instance' now handles general arities with general sorts
   297   (i.e. intersections of classes),
   298 
   299 * Presentation: generated HTML now uses a CSS style sheet to make layout
   300   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   301   It can be changed to alter the colors/layout of generated pages.
   302 
   303 
   304 *** Isar ***
   305 
   306 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   307   cut_tac, subgoal_tac and thin_tac:
   308   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   309     locales are no longer forced to write Isar proof scripts.
   310     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   311     emulations.
   312   - INCOMPATIBILITY: names of variables to be instantiated may no
   313     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   314     This is consistent with the instantiation attribute "where".
   315 
   316 * Attributes "where" and "of":
   317   - Now take type variables of instantiated theorem into account when reading
   318     the instantiation string.  This fixes a bug that caused instantiated
   319     theorems to have too special types in some circumstances.
   320   - "where" permits explicit instantiations of type variables.
   321 
   322 * Calculation commands "moreover" and "also" no longer interfere with
   323   current facts ("this"), admitting arbitrary combinations with "then"
   324   and derived forms.
   325 
   326 * Locales:
   327   - Goal statements involving the context element "includes" no longer
   328     generate theorems with internal delta predicates (those ending on
   329     "_axioms") in the premise.
   330     Resolve particular premise with <locale>.intro to obtain old form.
   331   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   332     specification and "includes" elements in goal statement.
   333   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   334     [intro?] and [elim?] (respectively) by default.
   335   - Experimental command for instantiation of locales in proof contexts:
   336         instantiate <label>[<attrs>]: <loc>
   337     Instantiates locale <loc> and adds all its theorems to the current context
   338     taking into account their attributes.  Label and attrs are optional
   339     modifiers, like in theorem declarations.  If present, names of
   340     instantiated theorems are qualified with <label>, and the attributes
   341     <attrs> are applied after any attributes these theorems might have already.
   342       If the locale has assumptions, a chained fact of the form
   343     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   344     are derived.  The command does not support old-style locales declared
   345     with "locale (open)".
   346       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   347 
   348 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   349   (Isar) contexts.
   350 
   351 
   352 *** HOL ***
   353 
   354 * Proof import: new image HOL4 contains the imported library from
   355   the HOL4 system with about 2500 theorems. It is imported by
   356   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   357   can be used like any other Isabelle image.  See
   358   HOL/Import/HOL/README for more information.
   359 
   360 * Simplifier:
   361   - Much improved handling of linear and partial orders.
   362     Reasoners for linear and partial orders are set up for type classes
   363     "linorder" and "order" respectively, and are added to the default simpset
   364     as solvers.  This means that the simplifier can build transitivity chains
   365     to solve goals from the assumptions.
   366   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   367     of blast or auto after simplification become unnecessary because the goal
   368     is solved by simplification already.
   369 
   370 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   371     all proved in axiomatic type classes for semirings, rings and fields.
   372 
   373 * Numerics:
   374   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   375     now formalized using the Ring_and_Field theory mentioned above.
   376   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   377     than before, because now they are set up once in a generic manner.
   378   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   379     Look for the general versions in Ring_and_Field (and Power if they concern
   380     exponentiation).
   381 
   382 * Type "rat" of the rational numbers is now available in HOL-Complex.
   383 
   384 * Records:
   385   - Record types are now by default printed with their type abbreviation
   386     instead of the list of all field types. This can be configured via
   387     the reference "print_record_type_abbr".
   388   - Simproc "record_upd_simproc" for simplification of multiple updates added
   389     (not enabled by default).
   390   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   391     EX x. x = sel r to True (not enabled by default).
   392   - Tactic "record_split_simp_tac" to split and simplify records added.
   393 
   394 * 'specification' command added, allowing for definition by
   395   specification.  There is also an 'ax_specification' command that
   396   introduces the new constants axiomatically.
   397 
   398 * arith(_tac) is now able to generate counterexamples for reals as well.
   399 
   400 * HOL-Algebra: new locale "ring" for non-commutative rings.
   401 
   402 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   403   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   404 
   405 * HOL-Matrix: a first theory for matrices in HOL with an application of
   406   matrix theory to linear programming.
   407 
   408 * Unions and Intersections:
   409   The latex output syntax of UN and INT has been changed
   410   from "\Union x \in A. B" to "\Union_{x \in A} B"
   411   i.e. the index formulae has become a subscript.
   412   Similarly for "\Union x. B", and for \Inter instead of \Union.
   413 
   414 * Unions and Intersections over Intervals:
   415   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   416   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   417   like in normal math, and corresponding versions for < and for intersection.
   418 
   419 * ML: the legacy theory structures Int and List have been removed. They had
   420   conflicted with ML Basis Library structures having the same names.
   421 
   422 * 'refute' command added to search for (finite) countermodels.  Only works
   423   for a fragment of HOL.  The installation of an external SAT solver is
   424   highly recommended.  See "HOL/Refute.thy" for details.
   425 
   426 * 'quickcheck' command: Allows to find counterexamples by evaluating
   427   formulae under an assignment of free variables to random values.
   428   In contrast to 'refute', it can deal with inductive datatypes,
   429   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   430   for examples.
   431 
   432 
   433 *** HOLCF ***
   434 
   435 * Streams now come with concatenation and are part of the HOLCF image
   436 
   437 
   438 
   439 New in Isabelle2003 (May 2003)
   440 ------------------------------
   441 
   442 *** General ***
   443 
   444 * Provers/simplifier:
   445 
   446   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   447     Assumptions are now subject to complete mutual simplification,
   448     not just from left to right. The simplifier now preserves
   449     the order of assumptions.
   450 
   451     Potential INCOMPATIBILITY:
   452 
   453     -- simp sometimes diverges where the old version did
   454        not, e.g. invoking simp on the goal
   455 
   456         [| P (f x); y = x; f x = f y |] ==> Q
   457 
   458        now gives rise to the infinite reduction sequence
   459 
   460         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   461 
   462        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   463        kind of problem.
   464 
   465     -- Tactics combining classical reasoner and simplification (such as auto)
   466        are also affected by this change, because many of them rely on
   467        simp. They may sometimes diverge as well or yield a different numbers
   468        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   469        in case of problems. Sometimes subsequent calls to the classical
   470        reasoner will fail because a preceeding call to the simplifier too
   471        eagerly simplified the goal, e.g. deleted redundant premises.
   472 
   473   - The simplifier trace now shows the names of the applied rewrite rules
   474 
   475   - You can limit the number of recursive invocations of the simplifier
   476     during conditional rewriting (where the simplifie tries to solve the
   477     conditions before applying the rewrite rule):
   478     ML "simp_depth_limit := n"
   479     where n is an integer. Thus you can force termination where previously
   480     the simplifier would diverge.
   481 
   482   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   483 
   484   - No longer aborts on failed congruence proof.  Instead, the
   485     congruence is ignored.
   486 
   487 * Pure: New generic framework for extracting programs from constructive
   488   proofs. See HOL/Extraction.thy for an example instantiation, as well
   489   as HOL/Extraction for some case studies.
   490 
   491 * Pure: The main goal of the proof state is no longer shown by default, only
   492 the subgoals. This behaviour is controlled by a new flag.
   493    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   494 (ML: Proof.show_main_goal).
   495 
   496 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   497 rules whose conclusion matches subgoal 1:
   498       PG menu: Isabelle/Isar -> Show me -> matching rules
   499 The rules are ordered by how closely they match the subgoal.
   500 In particular, rules that solve a subgoal outright are displayed first
   501 (or rather last, the way they are printed).
   502 (ML: ProofGeneral.print_intros())
   503 
   504 * Pure: New flag trace_unify_fail causes unification to print
   505 diagnostic information (PG: in trace buffer) when it fails. This is
   506 useful for figuring out why single step proofs like rule, erule or
   507 assumption failed.
   508 
   509 * Pure: Locale specifications now produce predicate definitions
   510 according to the body of text (covering assumptions modulo local
   511 definitions); predicate "loc_axioms" covers newly introduced text,
   512 while "loc" is cumulative wrt. all included locale expressions; the
   513 latter view is presented only on export into the global theory
   514 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   515 on the old view without predicates;
   516 
   517 * Pure: predefined locales "var" and "struct" are useful for sharing
   518 parameters (as in CASL, for example); just specify something like
   519 ``var x + var y + struct M'' as import;
   520 
   521 * Pure: improved thms_containing: proper indexing of facts instead of
   522 raw theorems; check validity of results wrt. current name space;
   523 include local facts of proof configuration (also covers active
   524 locales), cover fixed variables in index; may use "_" in term
   525 specification; an optional limit for the number of printed facts may
   526 be given (the default is 40);
   527 
   528 * Pure: disallow duplicate fact bindings within new-style theory files
   529 (batch-mode only);
   530 
   531 * Provers: improved induct method: assumptions introduced by case
   532 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   533 the goal statement); "foo" still refers to all facts collectively;
   534 
   535 * Provers: the function blast.overloaded has been removed: all constants
   536 are regarded as potentially overloaded, which improves robustness in exchange
   537 for slight decrease in efficiency;
   538 
   539 * Provers/linorder: New generic prover for transitivity reasoning over
   540 linear orders.  Note: this prover is not efficient!
   541 
   542 * Isar: preview of problems to finish 'show' now produce an error
   543 rather than just a warning (in interactive mode);
   544 
   545 
   546 *** HOL ***
   547 
   548 * arith(_tac)
   549 
   550  - Produces a counter example if it cannot prove a goal.
   551    Note that the counter example may be spurious if the goal is not a formula
   552    of quantifier-free linear arithmetic.
   553    In ProofGeneral the counter example appears in the trace buffer.
   554 
   555  - Knows about div k and mod k where k is a numeral of type nat or int.
   556 
   557  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   558    linear arithmetic fails. This takes account of quantifiers and divisibility.
   559    Presburger arithmetic can also be called explicitly via presburger(_tac).
   560 
   561 * simp's arithmetic capabilities have been enhanced a bit: it now
   562 takes ~= in premises into account (by performing a case split);
   563 
   564 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   565 are distributed over a sum of terms;
   566 
   567 * New tactic "trans_tac" and method "trans" instantiate
   568 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   569 "<=", "<" and "=").
   570 
   571 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   572 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   573 
   574 * 'typedef' command has new option "open" to suppress the set
   575 definition;
   576 
   577 * functions Min and Max on finite sets have been introduced (theory
   578 Finite_Set);
   579 
   580 * attribute [symmetric] now works for relations as well; it turns
   581 (x,y) : R^-1 into (y,x) : R, and vice versa;
   582 
   583 * induct over a !!-quantified statement (say !!x1..xn):
   584   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   585 
   586 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   587 %x. None. Warning: empty_def now refers to the previously hidden definition
   588 of the empty set.
   589 
   590 * Algebra: formalization of classical algebra.  Intended as base for
   591 any algebraic development in Isabelle.  Currently covers group theory
   592 (up to Sylow's theorem) and ring theory (Universal Property of
   593 Univariate Polynomials).  Contributions welcome;
   594 
   595 * GroupTheory: deleted, since its material has been moved to Algebra;
   596 
   597 * Complex: new directory of the complex numbers with numeric constants,
   598 nonstandard complex numbers, and some complex analysis, standard and
   599 nonstandard (Jacques Fleuriot);
   600 
   601 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   602 
   603 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   604 Fleuriot);
   605 
   606 * Real/HahnBanach: updated and adapted to locales;
   607 
   608 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   609 Gray and Kramer);
   610 
   611 * UNITY: added the Meier-Sanders theory of progress sets;
   612 
   613 * MicroJava: bytecode verifier and lightweight bytecode verifier
   614 as abstract algorithms, instantiated to the JVM;
   615 
   616 * Bali: Java source language formalization. Type system, operational
   617 semantics, axiomatic semantics. Supported language features:
   618 classes, interfaces, objects,virtual methods, static methods,
   619 static/instance fields, arrays, access modifiers, definite
   620 assignment, exceptions.
   621 
   622 
   623 *** ZF ***
   624 
   625 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   626 universe, etc.);
   627 
   628 * Main ZF: virtually all theories converted to new-style format;
   629 
   630 
   631 *** ML ***
   632 
   633 * Pure: Tactic.prove provides sane interface for internal proofs;
   634 omits the infamous "standard" operation, so this is more appropriate
   635 than prove_goalw_cterm in many situations (e.g. in simprocs);
   636 
   637 * Pure: improved error reporting of simprocs;
   638 
   639 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   640 up simprocs;
   641 
   642 
   643 *** Document preparation ***
   644 
   645 * uses \par instead of \\ for line breaks in theory text. This may
   646 shift some page breaks in large documents. To get the old behaviour
   647 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   648 
   649 * minimized dependencies of isabelle.sty and isabellesym.sty on
   650 other packages
   651 
   652 * \<euro> now needs package babel/greek instead of marvosym (which
   653 broke \Rightarrow)
   654 
   655 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   656 textcomp package)
   657 
   658 
   659 
   660 New in Isabelle2002 (March 2002)
   661 --------------------------------
   662 
   663 *** Document preparation ***
   664 
   665 * greatly simplified document preparation setup, including more
   666 graceful interpretation of isatool usedir -i/-d/-D options, and more
   667 instructive isatool mkdir; users should basically be able to get
   668 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   669 users may run a separate document processing stage manually like this:
   670 "isatool usedir -D output HOL Test && isatool document Test/output";
   671 
   672 * theory dependency graph may now be incorporated into documents;
   673 isatool usedir -g true will produce session_graph.eps/.pdf for use
   674 with \includegraphics of LaTeX;
   675 
   676 * proper spacing of consecutive markup elements, especially text
   677 blocks after section headings;
   678 
   679 * support bold style (for single symbols only), input syntax is like
   680 this: "\<^bold>\<alpha>" or "\<^bold>A";
   681 
   682 * \<bullet> is now output as bold \cdot by default, which looks much
   683 better in printed text;
   684 
   685 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   686 note that these symbols are currently unavailable in Proof General /
   687 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   688 
   689 * isatool latex no longer depends on changed TEXINPUTS, instead
   690 isatool document copies the Isabelle style files to the target
   691 location;
   692 
   693 
   694 *** Isar ***
   695 
   696 * Pure/Provers: improved proof by cases and induction;
   697   - 'case' command admits impromptu naming of parameters (such as
   698     "case (Suc n)");
   699   - 'induct' method divinates rule instantiation from the inductive
   700     claim; no longer requires excessive ?P bindings for proper
   701     instantiation of cases;
   702   - 'induct' method properly enumerates all possibilities of set/type
   703     rules; as a consequence facts may be also passed through *type*
   704     rules without further ado;
   705   - 'induct' method now derives symbolic cases from the *rulified*
   706     rule (before it used to rulify cases stemming from the internal
   707     atomized version); this means that the context of a non-atomic
   708     statement becomes is included in the hypothesis, avoiding the
   709     slightly cumbersome show "PROP ?case" form;
   710   - 'induct' may now use elim-style induction rules without chaining
   711     facts, using ``missing'' premises from the goal state; this allows
   712     rules stemming from inductive sets to be applied in unstructured
   713     scripts, while still benefitting from proper handling of non-atomic
   714     statements; NB: major inductive premises need to be put first, all
   715     the rest of the goal is passed through the induction;
   716   - 'induct' proper support for mutual induction involving non-atomic
   717     rule statements (uses the new concept of simultaneous goals, see
   718     below);
   719   - append all possible rule selections, but only use the first
   720     success (no backtracking);
   721   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   722   - undeclared rule case names default to numbers 1, 2, 3, ...;
   723   - added 'print_induct_rules' (covered by help item in recent Proof
   724     General versions);
   725   - moved induct/cases attributes to Pure, methods to Provers;
   726   - generic method setup instantiated for FOL and HOL;
   727 
   728 * Pure: support multiple simultaneous goal statements, for example
   729 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   730 meta-level mechanism, this acts as if several individual goals had
   731 been stated separately; in particular common proof methods need to be
   732 repeated in order to cover all claims; note that a single elimination
   733 step is *not* sufficient to establish the two conjunctions, so this
   734 fails:
   735 
   736   assume "A & B" then have A and B ..   (*".." fails*)
   737 
   738 better use "obtain" in situations as above; alternative refer to
   739 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   740 
   741 * Pure: proper integration with ``locales''; unlike the original
   742 version by Florian Kammller, Isar locales package high-level proof
   743 contexts rather than raw logical ones (e.g. we admit to include
   744 attributes everywhere); operations on locales include merge and
   745 rename; support for implicit arguments (``structures''); simultaneous
   746 type-inference over imports and text; see also HOL/ex/Locales.thy for
   747 some examples;
   748 
   749 * Pure: the following commands have been ``localized'', supporting a
   750 target locale specification "(in name)": 'lemma', 'theorem',
   751 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   752 stored both within the locale and at the theory level (exported and
   753 qualified by the locale name);
   754 
   755 * Pure: theory goals may now be specified in ``long'' form, with
   756 ad-hoc contexts consisting of arbitrary locale elements. for example
   757 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   758 definitions may be given, too); the result is a meta-level rule with
   759 the context elements being discharged in the obvious way;
   760 
   761 * Pure: new proof command 'using' allows to augment currently used
   762 facts after a goal statement ('using' is syntactically analogous to
   763 'apply', but acts on the goal's facts only); this allows chained facts
   764 to be separated into parts given before and after a claim, as in
   765 ``from a and b have C using d and e <proof>'';
   766 
   767 * Pure: renamed "antecedent" case to "rule_context";
   768 
   769 * Pure: new 'judgment' command records explicit information about the
   770 object-logic embedding (used by several tools internally); no longer
   771 use hard-wired "Trueprop";
   772 
   773 * Pure: added 'corollary' command;
   774 
   775 * Pure: fixed 'token_translation' command;
   776 
   777 * Pure: removed obsolete 'exported' attribute;
   778 
   779 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   780 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   781 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   782 
   783 * Pure: method 'atomize' presents local goal premises as object-level
   784 statements (atomic meta-level propositions); setup controlled via
   785 rewrite rules declarations of 'atomize' attribute; example
   786 application: 'induct' method with proper rule statements in improper
   787 proof *scripts*;
   788 
   789 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   790 now consider the syntactic context of assumptions, giving a better
   791 chance to get type-inference of the arguments right (this is
   792 especially important for locales);
   793 
   794 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   795 mode;
   796 
   797 * Pure/obtain: the formal conclusion "thesis", being marked as
   798 ``internal'', may no longer be reference directly in the text;
   799 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   800 situations;
   801 
   802 * Pure: generic 'sym' attribute which declares a rule both as pure
   803 'elim?' and for the 'symmetric' operation;
   804 
   805 * Pure: marginal comments ``--'' may now occur just anywhere in the
   806 text; the fixed correlation with particular command syntax has been
   807 discontinued;
   808 
   809 * Pure: new method 'rules' is particularly well-suited for proof
   810 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   811 but often produces more compact proof terms with less detours;
   812 
   813 * Pure/Provers/classical: simplified integration with pure rule
   814 attributes and methods; the classical "intro?/elim?/dest?"
   815 declarations coincide with the pure ones; the "rule" method no longer
   816 includes classically swapped intros; "intro" and "elim" methods no
   817 longer pick rules from the context; also got rid of ML declarations
   818 AddXIs/AddXEs/AddXDs; all of this has some potential for
   819 INCOMPATIBILITY;
   820 
   821 * Provers/classical: attribute 'swapped' produces classical inversions
   822 of introduction rules;
   823 
   824 * Provers/simplifier: 'simplified' attribute may refer to explicit
   825 rules instead of full simplifier context; 'iff' attribute handles
   826 conditional rules;
   827 
   828 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   829 
   830 * HOL: 'recdef' now fails on unfinished automated proofs, use
   831 "(permissive)" option to recover old behavior;
   832 
   833 * HOL: 'inductive' no longer features separate (collective) attributes
   834 for 'intros' (was found too confusing);
   835 
   836 * HOL: properly declared induction rules less_induct and
   837 wf_induct_rule;
   838 
   839 
   840 *** HOL ***
   841 
   842 * HOL: moved over to sane numeral syntax; the new policy is as
   843 follows:
   844 
   845   - 0 and 1 are polymorphic constants, which are defined on any
   846   numeric type (nat, int, real etc.);
   847 
   848   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   849   binary representation internally;
   850 
   851   - type nat has special constructor Suc, and generally prefers Suc 0
   852   over 1::nat and Suc (Suc 0) over 2::nat;
   853 
   854 This change may cause significant problems of INCOMPATIBILITY; here
   855 are some hints on converting existing sources:
   856 
   857   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   858   entities, so expressions involving "-" (unary or binary minus) need
   859   to be spaced properly;
   860 
   861   - existing occurrences of "1" may need to be constraint "1::nat" or
   862   even replaced by Suc 0; similar for old "2";
   863 
   864   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   865 
   866   - remove all special provisions on numerals in proofs;
   867 
   868 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   869 representation (depends on bin_arith_simps in the default context);
   870 
   871 * HOL: symbolic syntax for x^2 (numeral 2);
   872 
   873 * HOL: the class of all HOL types is now called "type" rather than
   874 "term"; INCOMPATIBILITY, need to adapt references to this type class
   875 in axclass/classes, instance/arities, and (usually rare) occurrences
   876 in typings (of consts etc.); internally the class is called
   877 "HOL.type", ML programs should refer to HOLogic.typeS;
   878 
   879 * HOL/record package improvements:
   880   - new derived operations "fields" to build a partial record section,
   881     "extend" to promote a fixed record to a record scheme, and
   882     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   883     declared as simp by default;
   884   - shared operations ("more", "fields", etc.) now need to be always
   885     qualified) --- potential INCOMPATIBILITY;
   886   - removed "make_scheme" operations (use "make" with "extend") --
   887     INCOMPATIBILITY;
   888   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   889   - provides cases/induct rules for use with corresponding Isar
   890     methods (for concrete records, record schemes, concrete more
   891     parts, and schematic more parts -- in that order);
   892   - internal definitions directly based on a light-weight abstract
   893     theory of product types over typedef rather than datatype;
   894 
   895 * HOL: generic code generator for generating executable ML code from
   896 specifications; specific support for HOL constructs such as inductive
   897 datatypes and sets, as well as recursive functions; can be invoked
   898 via 'generate_code' theory section;
   899 
   900 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   901 
   902 * HOL: consolidated and renamed several theories.  In particular:
   903         Ord.thy has been absorbed into HOL.thy
   904         String.thy has been absorbed into List.thy
   905 
   906 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   907 (beware of argument permutation!);
   908 
   909 * HOL: linorder_less_split superseded by linorder_cases;
   910 
   911 * HOL/List: "nodups" renamed to "distinct";
   912 
   913 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   914 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   915   - Ex_def has changed, now need to use some_eq_ex
   916 
   917 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   918 in this (rare) case use:
   919 
   920   delSWrapper "split_all_tac"
   921   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   922 
   923 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   924 MAY FAIL;
   925 
   926 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   927 Isabelle's type classes, ^ on functions and relations has too general
   928 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   929 necessary to attach explicit type constraints;
   930 
   931 * HOL/Relation: the prefix name of the infix "O" has been changed from
   932 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   933 renamed accordingly (eg "compI" -> "rel_compI").
   934 
   935 * HOL: syntax translations now work properly with numerals and records
   936 expressions;
   937 
   938 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   939 of "lam" -- INCOMPATIBILITY;
   940 
   941 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   942 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   943 renamed "Product_Type.unit";
   944 
   945 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   946 
   947 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   948 the "cases" method);
   949 
   950 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   951 Florian Kammller);
   952 
   953 * HOL/IMP: updated and converted to new-style theory format; several
   954 parts turned into readable document, with proper Isar proof texts and
   955 some explanations (by Gerwin Klein);
   956 
   957 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   958 
   959 * HOL-Hyperreal is now a logic image;
   960 
   961 
   962 *** HOLCF ***
   963 
   964 * Isar: consts/constdefs supports mixfix syntax for continuous
   965 operations;
   966 
   967 * Isar: domain package adapted to new-style theory format, e.g. see
   968 HOLCF/ex/Dnat.thy;
   969 
   970 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   971 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   972 lift.induct_tac, always use UU instead of Undef;
   973 
   974 * HOLCF/IMP: updated and converted to new-style theory;
   975 
   976 
   977 *** ZF ***
   978 
   979 * Isar: proper integration of logic-specific tools and packages,
   980 including theory commands '(co)inductive', '(co)datatype',
   981 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   982 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   983 
   984 * theory Main no longer includes AC; for the Axiom of Choice, base
   985 your theory on Main_ZFC;
   986 
   987 * the integer library now covers quotients and remainders, with many
   988 laws relating division to addition, multiplication, etc.;
   989 
   990 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   991 typeless version of the formalism;
   992 
   993 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   994 format;
   995 
   996 * ZF/Induct: new directory for examples of inductive definitions,
   997 including theory Multiset for multiset orderings; converted to
   998 new-style theory format;
   999 
  1000 * ZF: many new theorems about lists, ordinals, etc.;
  1001 
  1002 
  1003 *** General ***
  1004 
  1005 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1006 variable proof controls level of detail: 0 = no proofs (only oracle
  1007 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1008 also ref manual for further ML interfaces;
  1009 
  1010 * Pure/axclass: removed obsolete ML interface
  1011 goal_subclass/goal_arity;
  1012 
  1013 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1014 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1015 separate tokens, so expressions involving minus need to be spaced
  1016 properly;
  1017 
  1018 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1019 rather than "infixl" or "infixr";
  1020 
  1021 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1022 sort constraint specifications in type inference; e.g. "x::_::foo"
  1023 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1024 type variable);
  1025 
  1026 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1027 control output of nested => (types); the default behavior is
  1028 "type_brackets";
  1029 
  1030 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1031 tokens into AST constants;
  1032 
  1033 * Pure/syntax: prefer later declarations of translations and print
  1034 translation functions; potential INCOMPATIBILITY: need to reverse
  1035 multiple declarations for same syntax element constant;
  1036 
  1037 * Pure/show_hyps reset by default (in accordance to existing Isar
  1038 practice);
  1039 
  1040 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1041 addSafter;
  1042 
  1043 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1044 as well;
  1045 
  1046 * system: tested support for MacOS X; should be able to get Isabelle +
  1047 Proof General to work in a plain Terminal after installing Poly/ML
  1048 (e.g. from the Isabelle distribution area) and GNU bash alone
  1049 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1050 support requires further installations, e.g. from
  1051 http://fink.sourceforge.net/);
  1052 
  1053 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1054 
  1055 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1056 of 40 MB), cf. ML_OPTIONS;
  1057 
  1058 * system: Proof General keywords specification is now part of the
  1059 Isabelle distribution (see etc/isar-keywords.el);
  1060 
  1061 * system: support for persistent Proof General sessions (refrain from
  1062 outdating all loaded theories on startup); user may create writable
  1063 logic images like this: ``isabelle -q HOL Test'';
  1064 
  1065 * system: smart selection of Isabelle process versus Isabelle
  1066 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1067 run both "isabelle" and "Isabelle" even if file names are badly
  1068 damaged (executable inspects the case of the first letter of its own
  1069 name); added separate "isabelle-process" and "isabelle-interface";
  1070 
  1071 * system: refrain from any attempt at filtering input streams; no
  1072 longer support ``8bit'' encoding of old isabelle font, instead proper
  1073 iso-latin characters may now be used; the related isatools
  1074 "symbolinput" and "nonascii" have disappeared as well;
  1075 
  1076 * system: removed old "xterm" interface (the print modes "xterm" and
  1077 "xterm_color" are still available for direct use in a suitable
  1078 terminal);
  1079 
  1080 
  1081 
  1082 New in Isabelle99-2 (February 2001)
  1083 -----------------------------------
  1084 
  1085 *** Overview of INCOMPATIBILITIES ***
  1086 
  1087 * HOL: please note that theories in the Library and elsewhere often use the
  1088 new-style (Isar) format; to refer to their theorems in an ML script you must
  1089 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1090 
  1091 * HOL: inductive package no longer splits induction rule aggressively,
  1092 but only as far as specified by the introductions given; the old
  1093 format may be recovered via ML function complete_split_rule or attribute
  1094 'split_rule (complete)';
  1095 
  1096 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1097 gfp_Tarski to gfp_unfold;
  1098 
  1099 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1100 
  1101 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1102 relation); infix "^^" has been renamed "``"; infix "``" has been
  1103 renamed "`"; "univalent" has been renamed "single_valued";
  1104 
  1105 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1106 operation;
  1107 
  1108 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1109 
  1110 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1111 
  1112 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1113 consequence, it is no longer monotonic wrt. the local goal context
  1114 (which is now passed through the inductive cases);
  1115 
  1116 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1117 \<gg> to \<ggreater>;
  1118 
  1119 
  1120 *** Document preparation ***
  1121 
  1122 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1123 available: are "it" for near math-mode best-style output, "sl" for
  1124 slanted text style, and "tt" for plain type-writer; if no
  1125 \isabellestyle command is given, output is according to slanted
  1126 type-writer);
  1127 
  1128 * support sub/super scripts (for single symbols only), input syntax is
  1129 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1130 
  1131 * some more standard symbols; see Appendix A of the system manual for
  1132 the complete list of symbols defined in isabellesym.sty;
  1133 
  1134 * improved isabelle style files; more abstract symbol implementation
  1135 (should now use \isamath{...} and \isatext{...} in custom symbol
  1136 definitions);
  1137 
  1138 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1139 state; Note that presentation of goal states does not conform to
  1140 actual human-readable proof documents.  Please do not include goal
  1141 states into document output unless you really know what you are doing!
  1142 
  1143 * proper indentation of antiquoted output with proportional LaTeX
  1144 fonts;
  1145 
  1146 * no_document ML operator temporarily disables LaTeX document
  1147 generation;
  1148 
  1149 * isatool unsymbolize tunes sources for plain ASCII communication;
  1150 
  1151 
  1152 *** Isar ***
  1153 
  1154 * Pure: Isar now suffers initial goal statements to contain unbound
  1155 schematic variables (this does not conform to actual readable proof
  1156 documents, due to unpredictable outcome and non-compositional proof
  1157 checking); users who know what they are doing may use schematic goals
  1158 for Prolog-style synthesis of proven results;
  1159 
  1160 * Pure: assumption method (an implicit finishing) now handles actual
  1161 rules as well;
  1162 
  1163 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1164 initial goal, declare "that" only as Pure intro (only for single
  1165 steps); the "that" rule assumption may now be involved in implicit
  1166 finishing, thus ".." becomes a feasible for trivial obtains;
  1167 
  1168 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1169 instance proofs may be performed by "..";
  1170 
  1171 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1172 statements as well;
  1173 
  1174 * Pure: more robust selection of calculational rules;
  1175 
  1176 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1177 rule (as well as the assumption rule);
  1178 
  1179 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1180 lemmas, using the graph browser tool;
  1181 
  1182 * Pure: predict failure of "show" in interactive mode;
  1183 
  1184 * Pure: 'thms_containing' now takes actual terms as arguments;
  1185 
  1186 * HOL: improved method 'induct' --- now handles non-atomic goals
  1187 (potential INCOMPATIBILITY); tuned error handling;
  1188 
  1189 * HOL: cases and induct rules now provide explicit hints about the
  1190 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1191 any remaining facts are inserted into the goal verbatim;
  1192 
  1193 * HOL: local contexts (aka cases) may now contain term bindings as
  1194 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1195 the result to be shown in each case;
  1196 
  1197 * HOL: added 'recdef_tc' command;
  1198 
  1199 * isatool convert assists in eliminating legacy ML scripts;
  1200 
  1201 
  1202 *** HOL ***
  1203 
  1204 * HOL/Library: a collection of generic theories to be used together
  1205 with main HOL; the theory loader path already includes this directory
  1206 by default; the following existing theories have been moved here:
  1207 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1208 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1209 
  1210 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1211 modelling and verification task performed in Isabelle/HOL +
  1212 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1213 
  1214 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1215 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1216 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1217 'domain', this makes the theory consistent with mathematical
  1218 literature;
  1219 
  1220 * HOL basics: added overloaded operations "inverse" and "divide"
  1221 (infix "/"), syntax for generic "abs" operation, generic summation
  1222 operator \<Sum>;
  1223 
  1224 * HOL/typedef: simplified package, provide more useful rules (see also
  1225 HOL/subset.thy);
  1226 
  1227 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1228 now expressed as a proper nested rule (old-style tactic scripts may
  1229 require atomize_strip_tac to cope with non-atomic premises);
  1230 
  1231 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1232 to "split_conv" (old name still available for compatibility);
  1233 
  1234 * HOL: improved concrete syntax for strings (e.g. allows translation
  1235 rules with string literals);
  1236 
  1237 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1238  and Fleuriot's mechanization of analysis, including the transcendental
  1239  functions for the reals;
  1240 
  1241 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1242 
  1243 
  1244 *** CTT ***
  1245 
  1246 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1247 "lam" is displayed as TWO lambda-symbols
  1248 
  1249 * CTT: theory Main now available, containing everything (that is, Bool
  1250 and Arith);
  1251 
  1252 
  1253 *** General ***
  1254 
  1255 * Pure: the Simplifier has been implemented properly as a derived rule
  1256 outside of the actual kernel (at last!); the overall performance
  1257 penalty in practical applications is about 50%, while reliability of
  1258 the Isabelle inference kernel has been greatly improved;
  1259 
  1260 * print modes "brackets" and "no_brackets" control output of nested =>
  1261 (types) and ==> (props); the default behaviour is "brackets";
  1262 
  1263 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1264 as assumptions as well;
  1265 
  1266 * system: support Poly/ML 4.0;
  1267 
  1268 * system: isatool install handles KDE version 1 or 2;
  1269 
  1270 
  1271 
  1272 New in Isabelle99-1 (October 2000)
  1273 ----------------------------------
  1274 
  1275 *** Overview of INCOMPATIBILITIES ***
  1276 
  1277 * HOL: simplification of natural numbers is much changed; to partly
  1278 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1279 issue the following ML commands:
  1280 
  1281   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1282   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1283 
  1284 * HOL: simplification no longer dives into case-expressions; this is
  1285 controlled by "t.weak_case_cong" for each datatype t;
  1286 
  1287 * HOL: nat_less_induct renamed to less_induct;
  1288 
  1289 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1290 fixsome to patch .thy and .ML sources automatically;
  1291 
  1292   select_equality  -> some_equality
  1293   select_eq_Ex     -> some_eq_ex
  1294   selectI2EX       -> someI2_ex
  1295   selectI2         -> someI2
  1296   selectI          -> someI
  1297   select1_equality -> some1_equality
  1298   Eps_sym_eq       -> some_sym_eq_trivial
  1299   Eps_eq           -> some_eq_trivial
  1300 
  1301 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1302 
  1303 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1304 instead);
  1305 
  1306 * HOL: the recursion equations generated by 'recdef' are now called
  1307 f.simps instead of f.rules;
  1308 
  1309 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1310 
  1311 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1312 sometimes be needed;
  1313 
  1314 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1315 
  1316 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1317 
  1318 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1319 product is now "<*>" instead of "Times"; the lexicographic product is
  1320 now "<*lex*>" instead of "**";
  1321 
  1322 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1323 of main HOL, but was unused); better use HOL's datatype package;
  1324 
  1325 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1326 the old syntax may be recovered as follows:
  1327 
  1328   syntax (symbols)
  1329     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1330       (infixl "\\<oplus>" 100)
  1331 
  1332 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1333 
  1334 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1335 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1336 internally;
  1337 
  1338 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1339 changed from A/r to A//r;
  1340 
  1341 * ZF: new treatment of arithmetic (nat & int) may break some old
  1342 proofs;
  1343 
  1344 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1345 rulify -> rule_format, elimify -> elim_format, ...);
  1346 
  1347 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1348 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1349 should have to change intro!! to intro? only); replaced "delrule" by
  1350 "rule del";
  1351 
  1352 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1353 
  1354 * Provers: strengthened force_tac by using new first_best_tac;
  1355 
  1356 * LaTeX document preparation: several changes of isabelle.sty (see
  1357 lib/texinputs);
  1358 
  1359 
  1360 *** Document preparation ***
  1361 
  1362 * formal comments (text blocks etc.) in new-style theories may now
  1363 contain antiquotations of thm/prop/term/typ/text to be presented
  1364 according to latex print mode; concrete syntax is like this:
  1365 @{term[show_types] "f(x) = a + x"};
  1366 
  1367 * isatool mkdir provides easy setup of Isabelle session directories,
  1368 including proper document sources;
  1369 
  1370 * generated LaTeX sources are now deleted after successful run
  1371 (isatool document -c); may retain a copy somewhere else via -D option
  1372 of isatool usedir;
  1373 
  1374 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1375 style files, achieving self-contained LaTeX sources and simplifying
  1376 LaTeX debugging;
  1377 
  1378 * old-style theories now produce (crude) LaTeX output as well;
  1379 
  1380 * browser info session directories are now self-contained (may be put
  1381 on WWW server seperately); improved graphs of nested sessions; removed
  1382 graph for 'all sessions';
  1383 
  1384 * several improvements in isabelle style files; \isabellestyle{it}
  1385 produces fake math mode output; \isamarkupheader is now \section by
  1386 default; see lib/texinputs/isabelle.sty etc.;
  1387 
  1388 
  1389 *** Isar ***
  1390 
  1391 * Isar/Pure: local results and corresponding term bindings are now
  1392 subject to Hindley-Milner polymorphism (similar to ML); this
  1393 accommodates incremental type-inference very nicely;
  1394 
  1395 * Isar/Pure: new derived language element 'obtain' supports
  1396 generalized existence reasoning;
  1397 
  1398 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1399 support accumulation of results, without applying any rules yet;
  1400 useful to collect intermediate results without explicit name
  1401 references, and for use with transitivity rules with more than 2
  1402 premises;
  1403 
  1404 * Isar/Pure: scalable support for case-analysis type proofs: new
  1405 'case' language element refers to local contexts symbolically, as
  1406 produced by certain proof methods; internally, case names are attached
  1407 to theorems as "tags";
  1408 
  1409 * Isar/Pure: theory command 'hide' removes declarations from
  1410 class/type/const name spaces;
  1411 
  1412 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1413 indicate potential overloading;
  1414 
  1415 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1416 
  1417 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1418 "{a,b,c}" instead of {a,b,c};
  1419 
  1420 * Isar/Pure now provides its own version of intro/elim/dest
  1421 attributes; useful for building new logics, but beware of confusion
  1422 with the version in Provers/classical;
  1423 
  1424 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1425 case name 'antecedent';
  1426 
  1427 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1428 to the current context is now done automatically);
  1429 
  1430 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1431 for definining proof methods in ML;
  1432 
  1433 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1434 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1435 most cases, one should have to change intro!! to intro? only);
  1436 replaced "delrule" by "rule del";
  1437 
  1438 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1439 'symmetric' attribute (the latter supercedes [RS sym]);
  1440 
  1441 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1442 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1443 well (including splits);
  1444 
  1445 * Isar/Provers: Simplifier and Classical methods now support all kind
  1446 of modifiers used in the past, including 'cong', 'iff', etc.
  1447 
  1448 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1449 of Simplifier and Classical reasoner);
  1450 
  1451 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1452 now support named cases; major packages (inductive, datatype, primrec,
  1453 recdef) support case names and properly name parameters;
  1454 
  1455 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1456 monotonicity conditions are extracted to be proven at end of
  1457 calculations;
  1458 
  1459 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1460 method anyway;
  1461 
  1462 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1463 split_if split_if_asm; datatype package provides theorems foo.splits =
  1464 foo.split foo.split_asm for each datatype;
  1465 
  1466 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1467 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1468 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1469 use "(cases (simplified))" method in proper proof texts);
  1470 
  1471 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1472 
  1473 * Isar: names of theorems etc. may be natural numbers as well;
  1474 
  1475 * Isar: 'pr' command: optional arguments for goals_limit and
  1476 ProofContext.prems_limit; no longer prints theory contexts, but only
  1477 proof states;
  1478 
  1479 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1480 additional print modes to be specified; e.g. "pr(latex)" will print
  1481 proof state according to the Isabelle LaTeX style;
  1482 
  1483 * Isar: improved support for emulating tactic scripts, including proof
  1484 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1485 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1486 (for HOL datatypes);
  1487 
  1488 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1489 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1490 'proof method scripts' have to be in depth-first order;
  1491 
  1492 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1493 
  1494 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1495 should instead use individual commands for printing items
  1496 (print_commands, print_methods etc.);
  1497 
  1498 * Isar: added 'nothing' --- the empty list of theorems;
  1499 
  1500 
  1501 *** HOL ***
  1502 
  1503 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1504 corresponding virtual machine and a specification of its bytecode
  1505 verifier and a lightweight bytecode verifier, including proofs of
  1506 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1507 Cornelia Pusch (see also the homepage of project Bali at
  1508 http://isabelle.in.tum.de/Bali/);
  1509 
  1510 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1511 Clemens Ballarin;
  1512 
  1513 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1514 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1515 Rasmussen;
  1516 
  1517 * HOL/Lattice: fundamental concepts of lattice theory and order
  1518 structures, including duals, properties of bounds versus algebraic
  1519 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1520 Theorem for complete lattices etc.; may also serve as a demonstration
  1521 for abstract algebraic reasoning using axiomatic type classes, and
  1522 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1523 
  1524 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1525 von Oheimb;
  1526 
  1527 * HOL/IMPP: extension of IMP with local variables and mutually
  1528 recursive procedures, by David von Oheimb;
  1529 
  1530 * HOL/Lambda: converted into new-style theory and document;
  1531 
  1532 * HOL/ex/Multiquote: example of multiple nested quotations and
  1533 anti-quotations -- basically a generalized version of de-Bruijn
  1534 representation; very useful in avoiding lifting of operations;
  1535 
  1536 * HOL/record: added general record equality rule to simpset; fixed
  1537 select-update simplification procedure to handle extended records as
  1538 well; admit "r" as field name;
  1539 
  1540 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1541 other numeric types and also as the identity of groups, rings, etc.;
  1542 
  1543 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1544 Types nat and int belong to this axclass;
  1545 
  1546 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1547    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1548    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1549   two terms #m*u and #n*u are replaced by #(m+n)*u
  1550     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1551   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1552     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1553 
  1554 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1555 powerful prover for predicate logic but knows nothing of clasets; see
  1556 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1557 
  1558 * HOL: new version of "case_tac" subsumes both boolean case split and
  1559 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1560 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1561 
  1562 * HOL: simplification no longer dives into case-expressions: only the
  1563 selector expression is simplified, but not the remaining arms; to
  1564 enable full simplification of case-expressions for datatype t, you may
  1565 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1566 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1567 
  1568 * HOL/recdef: the recursion equations generated by 'recdef' for
  1569 function 'f' are now called f.simps instead of f.rules; if all
  1570 termination conditions are proved automatically, these simplification
  1571 rules are added to the simpset, as in primrec; rules may be named
  1572 individually as well, resulting in a separate list of theorems for
  1573 each equation;
  1574 
  1575 * HOL/While is a new theory that provides a while-combinator. It
  1576 permits the definition of tail-recursive functions without the
  1577 provision of a termination measure. The latter is necessary once the
  1578 invariant proof rule for while is applied.
  1579 
  1580 * HOL: new (overloaded) notation for the set of elements below/above
  1581 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1582 
  1583 * HOL: theorems impI, allI, ballI bound as "strip";
  1584 
  1585 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1586 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1587 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1588 
  1589 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1590 
  1591 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1592 main HOL, but was unused);
  1593 
  1594 * HOL: fewer consts declared as global (e.g. have to refer to
  1595 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1596 
  1597 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1598 in case of overlap with user translations (e.g. judgements over
  1599 tuples); (note that the underlying logical represenation is still
  1600 bogus);
  1601 
  1602 
  1603 *** ZF ***
  1604 
  1605 * ZF: simplification automatically cancels common terms in arithmetic
  1606 expressions over nat and int;
  1607 
  1608 * ZF: new treatment of nat to minimize type-checking: all operators
  1609 coerce their operands to a natural number using the function natify,
  1610 making the algebraic laws unconditional;
  1611 
  1612 * ZF: as above, for int: operators coerce their operands to an integer
  1613 using the function intify;
  1614 
  1615 * ZF: the integer library now contains many of the usual laws for the
  1616 orderings, including $<=, and monotonicity laws for $+ and $*;
  1617 
  1618 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1619 simplification;
  1620 
  1621 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1622 to the simplifier and classical reasoner simultaneously;
  1623 
  1624 
  1625 *** General ***
  1626 
  1627 * Provers: blast_tac now handles actual object-logic rules as
  1628 assumptions; note that auto_tac uses blast_tac internally as well;
  1629 
  1630 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1631 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1632 
  1633 * Provers: delrules now handles destruct rules as well (no longer need
  1634 explicit make_elim);
  1635 
  1636 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1637   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1638 use instead the strong form,
  1639   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1640 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1641 from destruct-rules;
  1642 
  1643 * Provers: Simplifier.easy_setup provides a fast path to basic
  1644 Simplifier setup for new object-logics;
  1645 
  1646 * Pure: AST translation rules no longer require constant head on LHS;
  1647 
  1648 * Pure: improved name spaces: ambiguous output is qualified; support
  1649 for hiding of names;
  1650 
  1651 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1652 XSYMBOL_HOME; no longer need to do manual configuration in most
  1653 situations;
  1654 
  1655 * system: compression of ML heaps images may now be controlled via -c
  1656 option of isabelle and isatool usedir (currently only observed by
  1657 Poly/ML);
  1658 
  1659 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1660 useful for remote X11);
  1661 
  1662 * system: provide TAGS file for Isabelle sources;
  1663 
  1664 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1665 order;
  1666 
  1667 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1668 timing flag supersedes proof_timing and Toplevel.trace;
  1669 
  1670 * ML: new combinators |>> and |>>> for incremental transformations
  1671 with secondary results (e.g. certain theory extensions):
  1672 
  1673 * ML: PureThy.add_defs gets additional argument to indicate potential
  1674 overloading (usually false);
  1675 
  1676 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1677 results;
  1678 
  1679 
  1680 
  1681 New in Isabelle99 (October 1999)
  1682 --------------------------------
  1683 
  1684 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1685 
  1686 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1687 are no longer simplified.  (This allows the simplifier to unfold recursive
  1688 functional programs.)  To restore the old behaviour, declare
  1689 
  1690     Delcongs [if_weak_cong];
  1691 
  1692 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1693 complement;
  1694 
  1695 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1696 
  1697 * HOL/datatype: mutual_induct_tac no longer exists --
  1698   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1699 
  1700 * HOL/typedef: fixed type inference for representing set; type
  1701 arguments now have to occur explicitly on the rhs as type constraints;
  1702 
  1703 * ZF: The con_defs part of an inductive definition may no longer refer
  1704 to constants declared in the same theory;
  1705 
  1706 * HOL, ZF: the function mk_cases, generated by the inductive
  1707 definition package, has lost an argument.  To simplify its result, it
  1708 uses the default simpset instead of a supplied list of theorems.
  1709 
  1710 * HOL/List: the constructors of type list are now Nil and Cons;
  1711 
  1712 * Simplifier: the type of the infix ML functions
  1713         setSSolver addSSolver setSolver addSolver
  1714 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1715 for packaging solvers. A solver is created via
  1716         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1717 where the string argument is only a comment.
  1718 
  1719 
  1720 *** Proof tools ***
  1721 
  1722 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1723 decision procedure for linear arithmetic. Currently it is used for
  1724 types `nat', `int', and `real' in HOL (see below); it can, should and
  1725 will be instantiated for other types and logics as well.
  1726 
  1727 * The simplifier now accepts rewrite rules with flexible heads, eg
  1728      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1729   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1730   matching.
  1731 
  1732 
  1733 *** General ***
  1734 
  1735 * New Isabelle/Isar subsystem provides an alternative to traditional
  1736 tactical theorem proving; together with the ProofGeneral/isar user
  1737 interface it offers an interactive environment for developing human
  1738 readable proof documents (Isar == Intelligible semi-automated
  1739 reasoning); for further information see isatool doc isar-ref,
  1740 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1741 
  1742 * improved and simplified presentation of theories: better HTML markup
  1743 (including colors), graph views in several sizes; isatool usedir now
  1744 provides a proper interface for user theories (via -P option); actual
  1745 document preparation based on (PDF)LaTeX is available as well (for
  1746 new-style theories only); see isatool doc system for more information;
  1747 
  1748 * native support for Proof General, both for classic Isabelle and
  1749 Isabelle/Isar;
  1750 
  1751 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1752 using the graph browser tool;
  1753 
  1754 * Isabelle manuals now also available as PDF;
  1755 
  1756 * theory loader rewritten from scratch (may not be fully
  1757 bug-compatible); old loadpath variable has been replaced by show_path,
  1758 add_path, del_path, reset_path functions; new operations such as
  1759 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1760 isatool doc ref);
  1761 
  1762 * improved isatool install: option -k creates KDE application icon,
  1763 option -p DIR installs standalone binaries;
  1764 
  1765 * added ML_PLATFORM setting (useful for cross-platform installations);
  1766 more robust handling of platform specific ML images for SML/NJ;
  1767 
  1768 * the settings environment is now statically scoped, i.e. it is never
  1769 created again in sub-processes invoked from isabelle, isatool, or
  1770 Isabelle;
  1771 
  1772 * path element specification '~~' refers to '$ISABELLE_HOME';
  1773 
  1774 * in locales, the "assumes" and "defines" parts may be omitted if
  1775 empty;
  1776 
  1777 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1778 long arrows);
  1779 
  1780 * new print_mode "HTML";
  1781 
  1782 * new flag show_tags controls display of tags of theorems (which are
  1783 basically just comments that may be attached by some tools);
  1784 
  1785 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1786 mode and goal output format:
  1787 
  1788 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1789 244c244
  1790 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1791 ---
  1792 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1793 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1794 181c181
  1795 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1796 ---
  1797 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1798 
  1799 * function bind_thms stores lists of theorems (cf. bind_thm);
  1800 
  1801 * new shorthand tactics ftac, eatac, datac, fatac;
  1802 
  1803 * qed (and friends) now accept "" as result name; in that case the
  1804 theorem is not stored, but proper checks and presentation of the
  1805 result still apply;
  1806 
  1807 * theorem database now also indexes constants "Trueprop", "all",
  1808 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1809 
  1810 
  1811 *** HOL ***
  1812 
  1813 ** HOL arithmetic **
  1814 
  1815 * There are now decision procedures for linear arithmetic over nat and
  1816 int:
  1817 
  1818 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1819 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1820 are treated as atomic; subformulae not involving type `nat' or `int'
  1821 are ignored; quantified subformulae are ignored unless they are
  1822 positive universal or negative existential. The tactic has to be
  1823 invoked by hand and can be a little bit slow. In particular, the
  1824 running time is exponential in the number of occurrences of `min' and
  1825 `max', and `-' on `nat'.
  1826 
  1827 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1828 (negated) (in)equalities among the premises and the conclusion into
  1829 account (i.e. no compound formulae) and does not know about `min' and
  1830 `max', and `-' on `nat'. It is fast and is used automatically by the
  1831 simplifier.
  1832 
  1833 NB: At the moment, these decision procedures do not cope with mixed
  1834 nat/int formulae where the two parts interact, such as `m < n ==>
  1835 int(m) < int(n)'.
  1836 
  1837 * HOL/Numeral provides a generic theory of numerals (encoded
  1838 efficiently as bit strings); setup for types nat/int/real is in place;
  1839 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1840 int, existing theories and proof scripts may require a few additional
  1841 type constraints;
  1842 
  1843 * integer division and remainder can now be performed on constant
  1844 arguments;
  1845 
  1846 * many properties of integer multiplication, division and remainder
  1847 are now available;
  1848 
  1849 * An interface to the Stanford Validity Checker (SVC) is available through the
  1850 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1851 are proved automatically.  SVC must be installed separately, and its results
  1852 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1853 invocation of the underlying oracle).  For SVC see
  1854   http://verify.stanford.edu/SVC
  1855 
  1856 * IsaMakefile: the HOL-Real target now builds an actual image;
  1857 
  1858 
  1859 ** HOL misc **
  1860 
  1861 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1862 (in Isabelle/Isar) -- by Gertrud Bauer;
  1863 
  1864 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1865 analysis for assembly languages with subtypes;
  1866 
  1867 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1868 -- avoids syntactic ambiguities and treats state, transition, and
  1869 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1870 changed syntax and (many) tactics;
  1871 
  1872 * HOL/inductive: Now also handles more general introduction rules such
  1873   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1874   theorems are now maintained within the theory (maintained via the
  1875   "mono" attribute);
  1876 
  1877 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1878   (using function types) such as
  1879 
  1880   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1881 
  1882 * HOL/record: record_simproc (part of the default simpset) takes care
  1883 of selectors applied to updated records; record_split_tac is no longer
  1884 part of the default claset; update_defs may now be removed from the
  1885 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1886 
  1887   claset_ref () := claset() addSWrapper record_split_wrapper;
  1888   Delsimprocs [record_simproc]
  1889 
  1890 * HOL/typedef: fixed type inference for representing set; type
  1891 arguments now have to occur explicitly on the rhs as type constraints;
  1892 
  1893 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1894 names rather than an ML expression;
  1895 
  1896 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1897 supplied later.  Program schemes can be defined, such as
  1898     "While B C s = (if B s then While B C (C s) else s)"
  1899 where the well-founded relation can be chosen after B and C have been given.
  1900 
  1901 * HOL/List: the constructors of type list are now Nil and Cons;
  1902 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1903 course, ML tools referring to List.list.op # etc. have to be adapted;
  1904 
  1905 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1906 disabled by default; run isabelle with option -m HOL to get back to
  1907 the original Gordon/HOL-style output;
  1908 
  1909 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1910 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1911 
  1912 * HOL basic syntax simplified (more orthogonal): all variants of
  1913 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1914 Eps operator is provided as well: "SOME x. P[x]";
  1915 
  1916 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1917 
  1918 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1919 thus available for user theories;
  1920 
  1921 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1922 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1923 time;
  1924 
  1925 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1926 several times and then mp;
  1927 
  1928 
  1929 *** LK ***
  1930 
  1931 * the notation <<...>> is now available as a notation for sequences of
  1932 formulas;
  1933 
  1934 * the simplifier is now installed
  1935 
  1936 * the axiom system has been generalized (thanks to Soren Heilmann)
  1937 
  1938 * the classical reasoner now has a default rule database
  1939 
  1940 
  1941 *** ZF ***
  1942 
  1943 * new primrec section allows primitive recursive functions to be given
  1944 directly (as in HOL) over datatypes and the natural numbers;
  1945 
  1946 * new tactics induct_tac and exhaust_tac for induction (or case
  1947 analysis) over datatypes and the natural numbers;
  1948 
  1949 * the datatype declaration of type T now defines the recursor T_rec;
  1950 
  1951 * simplification automatically does freeness reasoning for datatype
  1952 constructors;
  1953 
  1954 * automatic type-inference, with AddTCs command to insert new
  1955 type-checking rules;
  1956 
  1957 * datatype introduction rules are now added as Safe Introduction rules
  1958 to the claset;
  1959 
  1960 * the syntax "if P then x else y" is now available in addition to
  1961 if(P,x,y);
  1962 
  1963 
  1964 *** Internal programming interfaces ***
  1965 
  1966 * tuned simplifier trace output; new flag debug_simp;
  1967 
  1968 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1969 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1970 
  1971 * AxClass.axclass_tac lost the theory argument;
  1972 
  1973 * tuned current_goals_markers semantics: begin / end goal avoids
  1974 printing empty lines;
  1975 
  1976 * removed prs and prs_fn hook, which was broken because it did not
  1977 include \n in its semantics, forcing writeln to add one
  1978 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1979 string -> unit if you really want to output text without newline;
  1980 
  1981 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1982 plain output, interface builders may have to enable 'isabelle_font'
  1983 mode to get Isabelle font glyphs as before;
  1984 
  1985 * refined token_translation interface; INCOMPATIBILITY: output length
  1986 now of type real instead of int;
  1987 
  1988 * theory loader actions may be traced via new ThyInfo.add_hook
  1989 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1990 your own database of information attached to *whole* theories -- as
  1991 opposed to intra-theory data slots offered via TheoryDataFun;
  1992 
  1993 * proper handling of dangling sort hypotheses (at last!);
  1994 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1995 extra sort hypotheses that can be witnessed from the type signature;
  1996 the force_strip_shyps flag is gone, any remaining shyps are simply
  1997 left in the theorem (with a warning issued by strip_shyps_warning);
  1998 
  1999 
  2000 
  2001 New in Isabelle98-1 (October 1998)
  2002 ----------------------------------
  2003 
  2004 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2005 
  2006 * several changes of automated proof tools;
  2007 
  2008 * HOL: major changes to the inductive and datatype packages, including
  2009 some minor incompatibilities of theory syntax;
  2010 
  2011 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2012 called `inj_on';
  2013 
  2014 * HOL: removed duplicate thms in Arith:
  2015   less_imp_add_less  should be replaced by  trans_less_add1
  2016   le_imp_add_le      should be replaced by  trans_le_add1
  2017 
  2018 * HOL: unary minus is now overloaded (new type constraints may be
  2019 required);
  2020 
  2021 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2022 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2023 now taken as an integer constant.
  2024 
  2025 * Pure: ML function 'theory_of' renamed to 'theory';
  2026 
  2027 
  2028 *** Proof tools ***
  2029 
  2030 * Simplifier:
  2031   1. Asm_full_simp_tac is now more aggressive.
  2032      1. It will sometimes reorient premises if that increases their power to
  2033         simplify.
  2034      2. It does no longer proceed strictly from left to right but may also
  2035         rotate premises to achieve further simplification.
  2036      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2037      old Asm_full_simp_tac in that it does not rotate premises.
  2038   2. The simplifier now knows a little bit about nat-arithmetic.
  2039 
  2040 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2041 allows for selected deletion of wrappers, by introduction of names for
  2042 wrapper functionals.  This implies that addbefore, addSbefore,
  2043 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2044 and that adding two tactics with the same name overwrites the first
  2045 one (emitting a warning).
  2046   type wrapper = (int -> tactic) -> (int -> tactic)
  2047   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2048   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2049   delWrapper, delSWrapper: claset *  string            -> claset
  2050   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2051 
  2052 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2053 semantics; addbefore now affects only the unsafe part of step_tac
  2054 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2055 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2056 by Force_tac;
  2057 
  2058 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2059 compWrapper; added safe wrapper (and access functions for it);
  2060 
  2061 * HOL/split_all_tac is now much faster and fails if there is nothing
  2062 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2063 and the names of the automatically generated variables have changed.
  2064 split_all_tac has moved within claset() from unsafe wrappers to safe
  2065 wrappers, which means that !!-bound variables are split much more
  2066 aggressively, and safe_tac and clarify_tac now split such variables.
  2067 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2068 Note: the same holds for record_split_tac, which does the job of
  2069 split_all_tac for record fields.
  2070 
  2071 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2072 permanently to the default simpset using Addsplits just like
  2073 Addsimps. They can be removed via Delsplits just like
  2074 Delsimps. Lower-case versions are also available.
  2075 
  2076 * HOL/Simplifier: The rule split_if is now part of the default
  2077 simpset. This means that the simplifier will eliminate all occurrences
  2078 of if-then-else in the conclusion of a goal. To prevent this, you can
  2079 either remove split_if completely from the default simpset by
  2080 `Delsplits [split_if]' or remove it in a specific call of the
  2081 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2082 other case splitting rules to/from the default simpset: every datatype
  2083 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2084 t is the name of the datatype).
  2085 
  2086 * Classical reasoner / Simplifier combination: new force_tac (and
  2087 derivatives Force_tac, force) combines rewriting and classical
  2088 reasoning (and whatever other tools) similarly to auto_tac, but is
  2089 aimed to solve the given subgoal completely.
  2090 
  2091 
  2092 *** General ***
  2093 
  2094 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2095 and `goalw': the theory is no longer needed as an explicit argument -
  2096 the current theory context is used; assumptions are no longer returned
  2097 at the ML-level unless one of them starts with ==> or !!; it is
  2098 recommended to convert to these new commands using isatool fixgoal
  2099 (backup your sources first!);
  2100 
  2101 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2102 the current theory context, and 'theory' to lookup stored theories;
  2103 
  2104 * new theory section 'locale' for declaring constants, assumptions and
  2105 definitions that have local scope;
  2106 
  2107 * new theory section 'nonterminals' for purely syntactic types;
  2108 
  2109 * new theory section 'setup' for generic ML setup functions
  2110 (e.g. package initialization);
  2111 
  2112 * the distribution now includes Isabelle icons: see
  2113 lib/logo/isabelle-{small,tiny}.xpm;
  2114 
  2115 * isatool install - install binaries with absolute references to
  2116 ISABELLE_HOME/bin;
  2117 
  2118 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2119 
  2120 * print mode 'emacs' reserved for Isamode;
  2121 
  2122 * support multiple print (ast) translations per constant name;
  2123 
  2124 * theorems involving oracles are now printed with a suffixed [!];
  2125 
  2126 
  2127 *** HOL ***
  2128 
  2129 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2130 
  2131 * HOL/inductive package reorganized and improved: now supports mutual
  2132 definitions such as
  2133 
  2134   inductive EVEN ODD
  2135     intrs
  2136       null "0 : EVEN"
  2137       oddI "n : EVEN ==> Suc n : ODD"
  2138       evenI "n : ODD ==> Suc n : EVEN"
  2139 
  2140 new theorem list "elims" contains an elimination rule for each of the
  2141 recursive sets; inductive definitions now handle disjunctive premises
  2142 correctly (also ZF);
  2143 
  2144 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2145 "mutual_induct" no longer exists - the induction rule is always
  2146 contained in "induct";
  2147 
  2148 
  2149 * HOL/datatype package re-implemented and greatly improved: now
  2150 supports mutually recursive datatypes such as
  2151 
  2152   datatype
  2153     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2154             | SUM ('a aexp) ('a aexp)
  2155             | DIFF ('a aexp) ('a aexp)
  2156             | NUM 'a
  2157   and
  2158     'a bexp = LESS ('a aexp) ('a aexp)
  2159             | AND ('a bexp) ('a bexp)
  2160             | OR ('a bexp) ('a bexp)
  2161 
  2162 as well as indirectly recursive datatypes such as
  2163 
  2164   datatype
  2165     ('a, 'b) term = Var 'a
  2166                   | App 'b ((('a, 'b) term) list)
  2167 
  2168 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2169 induction on mutually / indirectly recursive datatypes.
  2170 
  2171 Primrec equations are now stored in theory and can be accessed via
  2172 <function_name>.simps.
  2173 
  2174 INCOMPATIBILITIES:
  2175 
  2176   - Theories using datatypes must now have theory Datatype as an
  2177     ancestor.
  2178   - The specific <typename>.induct_tac no longer exists - use the
  2179     generic induct_tac instead.
  2180   - natE has been renamed to nat.exhaust - use exhaust_tac
  2181     instead of res_inst_tac ... natE. Note that the variable
  2182     names in nat.exhaust differ from the names in natE, this
  2183     may cause some "fragile" proofs to fail.
  2184   - The theorems split_<typename>_case and split_<typename>_case_asm
  2185     have been renamed to <typename>.split and <typename>.split_asm.
  2186   - Since default sorts of type variables are now handled correctly,
  2187     some datatype definitions may have to be annotated with explicit
  2188     sort constraints.
  2189   - Primrec definitions no longer require function name and type
  2190     of recursive argument.
  2191 
  2192 Consider using isatool fixdatatype to adapt your theories and proof
  2193 scripts to the new package (backup your sources first!).
  2194 
  2195 
  2196 * HOL/record package: considerably improved implementation; now
  2197 includes concrete syntax for record types, terms, updates; theorems
  2198 for surjective pairing and splitting !!-bound record variables; proof
  2199 support is as follows:
  2200 
  2201   1) standard conversions (selectors or updates applied to record
  2202 constructor terms) are part of the standard simpset;
  2203 
  2204   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2205 made part of standard simpset and claset via addIffs;
  2206 
  2207   3) a tactic for record field splitting (record_split_tac) is part of
  2208 the standard claset (addSWrapper);
  2209 
  2210 To get a better idea about these rules you may retrieve them via
  2211 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2212 the name of your record type.
  2213 
  2214 The split tactic 3) conceptually simplifies by the following rule:
  2215 
  2216   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2217 
  2218 Thus any record variable that is bound by meta-all will automatically
  2219 blow up into some record constructor term, consequently the
  2220 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2221 solve record problems automatically.
  2222 
  2223 
  2224 * reorganized the main HOL image: HOL/Integ and String loaded by
  2225 default; theory Main includes everything;
  2226 
  2227 * automatic simplification of integer sums and comparisons, using cancellation;
  2228 
  2229 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2230 
  2231 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2232 
  2233 * many new identities for unions, intersections, set difference, etc.;
  2234 
  2235 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2236 called split_if, split_split, split_sum_case and split_nat_case (to go
  2237 with add/delsplits);
  2238 
  2239 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2240 (?x::unit) = (); this is made part of the default simpset, which COULD
  2241 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2242 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2243 unit_abs_eta_conv is added in order to counter the effect of
  2244 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2245 %u.f();
  2246 
  2247 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2248 makes more sense);
  2249 
  2250 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2251   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2252   disjointness reasoning but breaking a few old proofs.
  2253 
  2254 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2255 to 'converse' from 'inverse' (for compatibility with ZF and some
  2256 literature);
  2257 
  2258 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2259 the well-founded relation;
  2260 
  2261 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2262     Compl A.  The "Compl" syntax remains available as input syntax for this
  2263     release ONLY.
  2264 
  2265 * HOL/Update: new theory of function updates:
  2266     f(a:=b) == %x. if x=a then b else f x
  2267 may also be iterated as in f(a:=b,c:=d,...);
  2268 
  2269 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2270 
  2271 * HOL/List:
  2272   - new function list_update written xs[i:=v] that updates the i-th
  2273     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2274   - new function `upt' written [i..j(] which generates the list
  2275     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2276     bound write [i..j], which is a shorthand for [i..j+1(].
  2277   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2278 
  2279 * HOL/Arith:
  2280   - removed 'pred' (predecessor) function;
  2281   - generalized some theorems about n-1;
  2282   - many new laws about "div" and "mod";
  2283   - new laws about greatest common divisors (see theory ex/Primes);
  2284 
  2285 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2286 instead of "inverse";
  2287 
  2288 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2289   of the multiset ordering;
  2290 
  2291 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2292   (not included by default);
  2293 
  2294 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2295 
  2296 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2297   programs, i.e. different program variables may have different types.
  2298 
  2299 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2300   [previously, this check worked only if the rewrite rule was unconditional]
  2301   Now rew can involve either definitions or equalities (either == or =).
  2302 
  2303 
  2304 *** ZF ***
  2305 
  2306 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2307   only the theorems proved on ZF.ML;
  2308 
  2309 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2310   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2311   disjointness reasoning but breaking a few old proofs.
  2312 
  2313 * ZF/Update: new theory of function updates
  2314     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2315   may also be iterated as in f(a:=b,c:=d,...);
  2316 
  2317 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2318 
  2319 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2320   [previously, this check worked only if the rewrite rule was unconditional]
  2321   Now rew can involve either definitions or equalities (either == or =).
  2322 
  2323 * case_tac provided for compatibility with HOL
  2324     (like the old excluded_middle_tac, but with subgoals swapped)
  2325 
  2326 
  2327 *** Internal programming interfaces ***
  2328 
  2329 * Pure: several new basic modules made available for general use, see
  2330 also src/Pure/README;
  2331 
  2332 * improved the theory data mechanism to support encapsulation (data
  2333 kind name replaced by private Object.kind, acting as authorization
  2334 key); new type-safe user interface via functor TheoryDataFun; generic
  2335 print_data function becomes basically useless;
  2336 
  2337 * removed global_names compatibility flag -- all theory declarations
  2338 are qualified by default;
  2339 
  2340 * module Pure/Syntax now offers quote / antiquote translation
  2341 functions (useful for Hoare logic etc. with implicit dependencies);
  2342 see HOL/ex/Antiquote for an example use;
  2343 
  2344 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2345 cterm -> thm;
  2346 
  2347 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2348 subgoal;
  2349 
  2350 * Display.print_goals function moved to Locale.print_goals;
  2351 
  2352 * standard print function for goals supports current_goals_markers
  2353 variable for marking begin of proof, end of proof, start of goal; the
  2354 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2355 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2356 for example;
  2357 
  2358 
  2359 
  2360 New in Isabelle98 (January 1998)
  2361 --------------------------------
  2362 
  2363 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2364 
  2365 * changed lexical syntax of terms / types: dots made part of long
  2366 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2367 
  2368 * simpset (and claset) reference variable replaced by functions
  2369 simpset / simpset_ref;
  2370 
  2371 * no longer supports theory aliases (via merge) and non-trivial
  2372 implicit merge of thms' signatures;
  2373 
  2374 * most internal names of constants changed due to qualified names;
  2375 
  2376 * changed Pure/Sequence interface (see Pure/seq.ML);
  2377 
  2378 
  2379 *** General Changes ***
  2380 
  2381 * hierachically structured name spaces (for consts, types, axms, thms
  2382 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2383 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2384 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2385 long_names for fully qualified output names; NOTE: ML programs
  2386 (special tactics, packages etc.) referring to internal names may have
  2387 to be adapted to cope with fully qualified names; in case of severe
  2388 backward campatibility problems try setting 'global_names' at compile
  2389 time to have enrything declared within a flat name space; one may also
  2390 fine tune name declarations in theories via the 'global' and 'local'
  2391 section;
  2392 
  2393 * reimplemented the implicit simpset and claset using the new anytype
  2394 data filed in signatures; references simpset:simpset ref etc. are
  2395 replaced by functions simpset:unit->simpset and
  2396 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2397 to patch your ML files accordingly;
  2398 
  2399 * HTML output now includes theory graph data for display with Java
  2400 applet or isatool browser; data generated automatically via isatool
  2401 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2402 
  2403 * defs may now be conditional; improved rewrite_goals_tac to handle
  2404 conditional equations;
  2405 
  2406 * defs now admits additional type arguments, using TYPE('a) syntax;
  2407 
  2408 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2409 creates a new theory node; implicit merge of thms' signatures is
  2410 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2411 transfer:theory->thm->thm in (rare) cases;
  2412 
  2413 * improved handling of draft signatures / theories; draft thms (and
  2414 ctyps, cterms) are automatically promoted to real ones;
  2415 
  2416 * slightly changed interfaces for oracles: admit many per theory, named
  2417 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2418 
  2419 * print_goals: optional output of const types (set show_consts and
  2420 show_types);
  2421 
  2422 * improved output of warnings (###) and errors (***);
  2423 
  2424 * subgoal_tac displays a warning if the new subgoal has type variables;
  2425 
  2426 * removed old README and Makefiles;
  2427 
  2428 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2429 
  2430 * removed obsolete init_pps and init_database;
  2431 
  2432 * deleted the obsolete tactical STATE, which was declared by
  2433     fun STATE tacfun st = tacfun st st;
  2434 
  2435 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2436 (which abbreviates $HOME);
  2437 
  2438 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2439 use isatool fixseq to adapt your ML programs (this works for fully
  2440 qualified references to the Sequence structure only!);
  2441 
  2442 * use_thy no longer requires writable current directory; it always
  2443 reloads .ML *and* .thy file, if either one is out of date;
  2444 
  2445 
  2446 *** Classical Reasoner ***
  2447 
  2448 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2449 tactics that use classical reasoning to simplify a subgoal without
  2450 splitting it into several subgoals;
  2451 
  2452 * Safe_tac: like safe_tac but uses the default claset;
  2453 
  2454 
  2455 *** Simplifier ***
  2456 
  2457 * added simplification meta rules:
  2458     (asm_)(full_)simplify: simpset -> thm -> thm;
  2459 
  2460 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2461 logics (again);
  2462 
  2463 * added prems argument to simplification procedures;
  2464 
  2465 * HOL, FOL, ZF: added infix function `addsplits':
  2466   instead of `<simpset> setloop (split_tac <thms>)'
  2467   you can simply write `<simpset> addsplits <thms>'
  2468 
  2469 
  2470 *** Syntax ***
  2471 
  2472 * TYPE('a) syntax for type reflection terms;
  2473 
  2474 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2475 
  2476 * pretty printer: changed order of mixfix annotation preference (again!);
  2477 
  2478 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2479 
  2480 
  2481 *** HOL ***
  2482 
  2483 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2484   with `addloop' of the simplifier to faciliate case splitting in premises.
  2485 
  2486 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2487 
  2488 * HOL/Auth: new protocol proofs including some for the Internet
  2489   protocol TLS;
  2490 
  2491 * HOL/Map: new theory of `maps' a la VDM;
  2492 
  2493 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2494 cancelling out common nat summands from =, <, <= (in)equalities, or
  2495 differences; simplification procedures nat_cancel_factor for
  2496 cancelling common factor from =, <, <= (in)equalities over natural
  2497 sums; nat_cancel contains both kinds of procedures, it is installed by
  2498 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2499 
  2500 * HOL/simplifier: terms of the form
  2501   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2502   are rewritten to
  2503   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2504   and those of the form
  2505   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2506   are rewritten to
  2507   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2508 
  2509 * HOL/datatype
  2510   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2511 
  2512   P(t_case f1 ... fn x) =
  2513      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2514         ...
  2515        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2516      )
  2517 
  2518   and a theorem `split_t_case_asm' of the form
  2519 
  2520   P(t_case f1 ... fn x) =
  2521     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2522         ...
  2523        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2524      )
  2525   which can be added to a simpset via `addsplits'. The existing theorems
  2526   expand_list_case and expand_option_case have been renamed to
  2527   split_list_case and split_option_case.
  2528 
  2529 * HOL/Arithmetic:
  2530   - `pred n' is automatically converted to `n-1'.
  2531     Users are strongly encouraged not to use `pred' any longer,
  2532     because it will disappear altogether at some point.
  2533   - Users are strongly encouraged to write "0 < n" rather than
  2534     "n ~= 0". Theorems and proof tools have been modified towards this
  2535     `standard'.
  2536 
  2537 * HOL/Lists:
  2538   the function "set_of_list" has been renamed "set" (and its theorems too);
  2539   the function "nth" now takes its arguments in the reverse order and
  2540   has acquired the infix notation "!" as in "xs!n".
  2541 
  2542 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2543 
  2544 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2545   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2546 
  2547 * HOL/record: extensible records with schematic structural subtyping
  2548 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2549 still lacks various theorems and concrete record syntax;
  2550 
  2551 
  2552 *** HOLCF ***
  2553 
  2554 * removed "axioms" and "generated by" sections;
  2555 
  2556 * replaced "ops" section by extended "consts" section, which is capable of
  2557   handling the continuous function space "->" directly;
  2558 
  2559 * domain package:
  2560   . proves theorems immediately and stores them in the theory,
  2561   . creates hierachical name space,
  2562   . now uses normal mixfix annotations (instead of cinfix...),
  2563   . minor changes to some names and values (for consistency),
  2564   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2565   . separator between mutual domain defs: changed "," to "and",
  2566   . improved handling of sort constraints;  now they have to
  2567     appear on the left-hand side of the equations only;
  2568 
  2569 * fixed LAM <x,y,zs>.b syntax;
  2570 
  2571 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2572 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2573 
  2574 
  2575 *** FOL and ZF ***
  2576 
  2577 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2578   with `addloop' of the simplifier to faciliate case splitting in premises.
  2579 
  2580 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2581 in HOL, they strip ALL and --> from proved theorems;
  2582 
  2583 
  2584 
  2585 New in Isabelle94-8 (May 1997)
  2586 ------------------------------
  2587 
  2588 *** General Changes ***
  2589 
  2590 * new utilities to build / run / maintain Isabelle etc. (in parts
  2591 still somewhat experimental); old Makefiles etc. still functional;
  2592 
  2593 * new 'Isabelle System Manual';
  2594 
  2595 * INSTALL text, together with ./configure and ./build scripts;
  2596 
  2597 * reimplemented type inference for greater efficiency, better error
  2598 messages and clean internal interface;
  2599 
  2600 * prlim command for dealing with lots of subgoals (an easier way of
  2601 setting goals_limit);
  2602 
  2603 
  2604 *** Syntax ***
  2605 
  2606 * supports alternative (named) syntax tables (parser and pretty
  2607 printer); internal interface is provided by add_modesyntax(_i);
  2608 
  2609 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2610 be used in conjunction with the Isabelle symbol font; uses the
  2611 "symbols" syntax table;
  2612 
  2613 * added token_translation interface (may translate name tokens in
  2614 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2615 the current print_mode); IMPORTANT: user print translation functions
  2616 are responsible for marking newly introduced bounds
  2617 (Syntax.mark_boundT);
  2618 
  2619 * token translations for modes "xterm" and "xterm_color" that display
  2620 names in bold, underline etc. or colors (which requires a color
  2621 version of xterm);
  2622 
  2623 * infixes may now be declared with names independent of their syntax;
  2624 
  2625 * added typed_print_translation (like print_translation, but may
  2626 access type of constant);
  2627 
  2628 
  2629 *** Classical Reasoner ***
  2630 
  2631 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2632 some limitations.  Blast_tac...
  2633   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2634   + ignores elimination rules that don't have the correct format
  2635         (the conclusion MUST be a formula variable)
  2636   + ignores types, which can make HOL proofs fail
  2637   + rules must not require higher-order unification, e.g. apply_type in ZF
  2638     [message "Function Var's argument not a bound variable" relates to this]
  2639   + its proof strategy is more general but can actually be slower
  2640 
  2641 * substitution with equality assumptions no longer permutes other
  2642 assumptions;
  2643 
  2644 * minor changes in semantics of addafter (now called addaltern); renamed
  2645 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2646 (and access functions for it);
  2647 
  2648 * improved combination of classical reasoner and simplifier:
  2649   + functions for handling clasimpsets
  2650   + improvement of addss: now the simplifier is called _after_ the
  2651     safe steps.
  2652   + safe variant of addss called addSss: uses safe simplifications
  2653     _during_ the safe steps. It is more complete as it allows multiple
  2654     instantiations of unknowns (e.g. with slow_tac).
  2655 
  2656 *** Simplifier ***
  2657 
  2658 * added interface for simplification procedures (functions that
  2659 produce *proven* rewrite rules on the fly, depending on current
  2660 redex);
  2661 
  2662 * ordering on terms as parameter (used for ordered rewriting);
  2663 
  2664 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2665 
  2666 * the solver is now split into a safe and an unsafe part.
  2667 This should be invisible for the normal user, except that the
  2668 functions setsolver and addsolver have been renamed to setSolver and
  2669 addSolver; added safe_asm_full_simp_tac;
  2670 
  2671 
  2672 *** HOL ***
  2673 
  2674 * a generic induction tactic `induct_tac' which works for all datatypes and
  2675 also for type `nat';
  2676 
  2677 * a generic case distinction tactic `exhaust_tac' which works for all
  2678 datatypes and also for type `nat';
  2679 
  2680 * each datatype comes with a function `size';
  2681 
  2682 * patterns in case expressions allow tuple patterns as arguments to
  2683 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2684 
  2685 * primrec now also works with type nat;
  2686 
  2687 * recdef: a new declaration form, allows general recursive functions to be
  2688 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2689 
  2690 * the constant for negation has been renamed from "not" to "Not" to
  2691 harmonize with FOL, ZF, LK, etc.;
  2692 
  2693 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2694 infinite lists;
  2695 
  2696 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2697 
  2698 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2699 problems in commutative rings, using axiomatic type classes for + and *;
  2700 
  2701 * more examples in HOL/MiniML and HOL/Auth;
  2702 
  2703 * more default rewrite rules for quantifiers, union/intersection;
  2704 
  2705 * a new constant `arbitrary == @x.False';
  2706 
  2707 * HOLCF/IOA replaces old HOL/IOA;
  2708 
  2709 * HOLCF changes: derived all rules and arities
  2710   + axiomatic type classes instead of classes
  2711   + typedef instead of faking type definitions
  2712   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2713   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2714   + eliminated the types void, one, tr
  2715   + use unit lift and bool lift (with translations) instead of one and tr
  2716   + eliminated blift from Lift3.thy (use Def instead of blift)
  2717   all eliminated rules are derived as theorems --> no visible changes ;
  2718 
  2719 
  2720 *** ZF ***
  2721 
  2722 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2723 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2724 as ZF_cs addSIs [equalityI];
  2725 
  2726 
  2727 
  2728 New in Isabelle94-7 (November 96)
  2729 ---------------------------------
  2730 
  2731 * allowing negative levels (as offsets) in prlev and choplev;
  2732 
  2733 * super-linear speedup for large simplifications;
  2734 
  2735 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2736 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2737 FAIL); can suppress it using the command Delsimps (ex_simps @
  2738 all_simps); De Morgan laws are also now included, by default;
  2739 
  2740 * improved printing of ==>  :  ~:
  2741 
  2742 * new object-logic "Sequents" adds linear logic, while replacing LK
  2743 and Modal (thanks to Sara Kalvala);
  2744 
  2745 * HOL/Auth: correctness proofs for authentication protocols;
  2746 
  2747 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2748 examples on HOL/Auth);
  2749 
  2750 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2751 the rewriter and classical reasoner simultaneously;
  2752 
  2753 * function uresult no longer returns theorems in "standard" format;
  2754 regain previous version by: val uresult = standard o uresult;
  2755 
  2756 
  2757 
  2758 New in Isabelle94-6
  2759 -------------------
  2760 
  2761 * oracles -- these establish an interface between Isabelle and trusted
  2762 external reasoners, which may deliver results as theorems;
  2763 
  2764 * proof objects (in particular record all uses of oracles);
  2765 
  2766 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2767 
  2768 * "constdefs" section in theory files;
  2769 
  2770 * "primrec" section (HOL) no longer requires names;
  2771 
  2772 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2773 
  2774 
  2775 
  2776 New in Isabelle94-5
  2777 -------------------
  2778 
  2779 * reduced space requirements;
  2780 
  2781 * automatic HTML generation from theories;
  2782 
  2783 * theory files no longer require "..." (quotes) around most types;
  2784 
  2785 * new examples, including two proofs of the Church-Rosser theorem;
  2786 
  2787 * non-curried (1994) version of HOL is no longer distributed;
  2788 
  2789 
  2790 
  2791 New in Isabelle94-4
  2792 -------------------
  2793 
  2794 * greatly reduced space requirements;
  2795 
  2796 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2797 
  2798 * searchable theorem database (see the section "Retrieving theorems" on
  2799 page 8 of the Reference Manual);
  2800 
  2801 * new examples, including Grabczewski's monumental case study of the
  2802 Axiom of Choice;
  2803 
  2804 * The previous version of HOL renamed to Old_HOL;
  2805 
  2806 * The new version of HOL (previously called CHOL) uses a curried syntax
  2807 for functions.  Application looks like f a b instead of f(a,b);
  2808 
  2809 * Mutually recursive inductive definitions finally work in HOL;
  2810 
  2811 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2812 translates to the operator "split";
  2813 
  2814 
  2815 
  2816 New in Isabelle94-3
  2817 -------------------
  2818 
  2819 * new infix operator, addss, allowing the classical reasoner to
  2820 perform simplification at each step of its search.  Example:
  2821         fast_tac (cs addss ss)
  2822 
  2823 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2824 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2825 look like (a,b) instead of <a,b>;
  2826 
  2827 * PLEASE NOTE: CHOL will eventually replace HOL!
  2828 
  2829 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2830 It translates to the operator "split".  A new theory of integers is available;
  2831 
  2832 * In ZF, integer numerals now denote two's-complement binary integers.
  2833 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2834 
  2835 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2836 of the Axiom of Choice;
  2837 
  2838 
  2839 
  2840 New in Isabelle94-2
  2841 -------------------
  2842 
  2843 * Significantly faster resolution;
  2844 
  2845 * the different sections in a .thy file can now be mixed and repeated
  2846 freely;
  2847 
  2848 * Database of theorems for FOL, HOL and ZF.  New
  2849 commands including qed, qed_goal and bind_thm store theorems in the database.
  2850 
  2851 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2852 a given theory (thms_of), or find out what theory a theorem was proved in
  2853 (theory_of_thm);
  2854 
  2855 * Bugs fixed in the inductive definition and datatype packages;
  2856 
  2857 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2858 and HOL_dup_cs obsolete;
  2859 
  2860 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2861 have been removed;
  2862 
  2863 * Simpler definition of function space in ZF;
  2864 
  2865 * new results about cardinal and ordinal arithmetic in ZF;
  2866 
  2867 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2868 types;
  2869 
  2870 
  2871 $Id$