NEWS
author skalberg
Wed Jun 30 00:42:59 2004 +0200 (2004-06-30)
changeset 15011 35be762f58f9
parent 14972 51f95648abad
child 15012 28fa57b57209
permissions -rw-r--r--
Made simplification procedures simpset-aware.
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Pure: Simplification procedures can now take the current simpset as
    10   an additional argument; This is useful for calling the simplifier
    11   recursively.  See the functions MetaSimplifier.full_{mk_simproc,
    12   simproc,simproc_i}.
    13 
    14 * Pure: considerably improved version of 'constdefs' command.  Now
    15   performs automatic type-inference of declared constants; additional
    16   support for local structure declarations (cf. locales and HOL
    17   records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    18   to observe strictly sequential dependencies of definitions within a
    19   single 'constdefs' section; moreover, the declared name needs to be
    20   an identifier.  If all fails, consider to fall back on 'consts' and
    21   'defs' separately.
    22 
    23 * Pure: improved indexed syntax and implicit structures.  First of
    24   all, indexed syntax provides a notational device for subscripted
    25   application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    26   expressions.  Secondly, in a local context with structure
    27   declarations, number indexes \<^sub>n or the empty index (default
    28   number 1) refer to a certain fixed variable implicitly; option
    29   show_structs controls printing of implicit structures.  Typical
    30   applications of these concepts involve record types and locales.
    31 
    32 * Pure: clear separation of logical types and nonterminals, where the
    33   latter may only occur in 'syntax' specifications or type
    34   abbreviations.  Before that distinction was only partially
    35   implemented via type class "logic" vs. "{}".  Potential
    36   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
    37   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
    38   specifications may require further adaption (e.g. Cube/Base.thy).
    39 
    40 * Pure: removed obsolete type class "logic", use the top sort {}
    41   instead.  Note that non-logical types should be declared as
    42   'nonterminals' rather than 'types'.  INCOMPATIBILITY for new
    43   object-logic specifications.
    44 
    45 * Pure/Syntax: inner syntax includes (*(*nested*) comments*).
    46 
    47 * Pure/Syntax: pretty pinter now supports unbreakable blocks,
    48   specified in mixfix annotations as "(00...)".
    49 
    50 * Pure/Syntax: 'advanced' translation functions (parse_translation
    51   etc.) may depend on the signature of the theory context being
    52   presently used for parsing/printing, see also isar-ref manual.
    53 
    54 * Pure: tuned internal renaming of symbolic identifiers -- attach
    55   primes instead of base 26 numbers.
    56 
    57 * Document preparation: antiquotations now provide the option
    58   'locale=NAME' to specify an alternative context used for evaluating
    59   and printing the subsequent argument, as in @{thm [locale=LC]
    60   fold_commute}, for example.
    61 
    62 * Document preparation: commands 'display_drafts' and 'print_drafts'
    63   perform simple output of raw sources.  Only those symbols that do
    64   not require additional LaTeX packages (depending on comments in
    65   isabellesym.sty) are displayed properly, everything else is left
    66   verbatim.  We use isatool display and isatool print as front ends;
    67   these are subject to the DVI_VIEWER and PRINT_COMMAND settings,
    68   respectively.
    69 
    70 * ML: output via the Isabelle channels of writeln/warning/error
    71   etc. is now passed through Output.output, with a hook for arbitrary
    72   transformations depending on the print_mode (cf. Output.add_mode --
    73   the first active mode that provides a output function wins).
    74   Already formatted output may be embedded into further text via
    75   Output.raw; the result of Pretty.string_of/str_of and derived
    76   functions (string_of_term/cterm/thm etc.) is already marked raw to
    77   accommodate easy composition of diagnostic messages etc.
    78   Programmers rarely need to care about Output.output or Output.raw at
    79   all, with some notable exceptions: Output.output is required when
    80   bypassing the standard channels (writeln etc.), or in token
    81   translations to produce properly formatted results; Output.raw is
    82   required when capturing already output material that will eventually
    83   be presented to the user a second time.  For the default print mode,
    84   both Output.output and Output.raw have no effect.
    85 
    86 
    87 *** HOL ***
    88 
    89 * HOL/record: reimplementation of records. Improved scalability for
    90   records with many fields, avoiding performance problems for type
    91   inference. Records are no longer composed of nested field types, but
    92   of nested extension types. Therefore the record type only grows
    93   linear in the number of extensions and not in the number of fields.
    94   The top-level (users) view on records is preserved.  Potential
    95   INCOMPATIBILITY only in strange cases, where the theory depends on
    96   the old record representation. The type generated for a record is
    97   called <record_name>_ext_type.
    98 
    99 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
   100 
   101   syntax (epsilon)
   102     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   103 
   104   The symbol \<some> is displayed as the alternative epsilon of LaTeX
   105   and x-symbol; use option '-m epsilon' to get it actually printed.
   106   Moreover, the mathematically important symbolic identifier
   107   \<epsilon> becomes available as variable, constant etc.
   108 
   109 * Simplifier: "record_upd_simproc" for simplification of multiple
   110   record updates enabled by default.  INCOMPATIBILITY: old proofs
   111   break occasionally, since simplification is more powerful by
   112   default.
   113 
   114 
   115 *** HOLCF ***
   116 
   117 * HOLCF: discontinued special version of 'constdefs' (which used to
   118   support continuous functions) in favor of the general Pure one with
   119   full type-inference.
   120 
   121 
   122 *** ZF ***
   123 
   124 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the First
   125   Isomorphism Theorem (on quotienting by the kernel of a homomorphism).
   126 
   127 
   128 
   129 New in Isabelle2004 (April 2004)
   130 --------------------------------
   131 
   132 *** General ***
   133 
   134 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   135   Replaces linorder.ML.
   136 
   137 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   138   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   139   (\<a>...\<z>), are now considered normal letters, and can therefore
   140   be used anywhere where an ASCII letter (a...zA...Z) has until
   141   now. COMPATIBILITY: This obviously changes the parsing of some
   142   terms, especially where a symbol has been used as a binder, say
   143   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   144   as an identifier.  Fix it by inserting a space around former
   145   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   146   existing theory and ML files.
   147 
   148 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   149 
   150 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   151   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   152   a normal (but invisible) letter. For multiple letter subscripts repeat
   153   \<^isub> like this: x\<^isub>1\<^isub>2.
   154 
   155 * Pure: There are now sub-/superscripts that can span more than one
   156   character. Text between \<^bsub> and \<^esub> is set in subscript in
   157   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   158   superscript. The new control characters are not identifier parts.
   159 
   160 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   161   content of "..." to the latex file instead of \isacntrl... . The "..."
   162   may consist of any printable characters excluding the end bracket >.
   163 
   164 * Pure: Using new Isar command "finalconsts" (or the ML functions
   165   Theory.add_finals or Theory.add_finals_i) it is now possible to
   166   declare constants "final", which prevents their being given a definition
   167   later.  It is useful for constants whose behaviour is fixed axiomatically
   168   rather than definitionally, such as the meta-logic connectives.
   169 
   170 * Pure: 'instance' now handles general arities with general sorts
   171   (i.e. intersections of classes),
   172 
   173 * Presentation: generated HTML now uses a CSS style sheet to make layout
   174   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   175   It can be changed to alter the colors/layout of generated pages.
   176 
   177 
   178 *** Isar ***
   179 
   180 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   181   cut_tac, subgoal_tac and thin_tac:
   182   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   183     locales are no longer forced to write Isar proof scripts.
   184     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   185     emulations.
   186   - INCOMPATIBILITY: names of variables to be instantiated may no
   187     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   188     This is consistent with the instantiation attribute "where".
   189 
   190 * Attributes "where" and "of":
   191   - Now take type variables of instantiated theorem into account when reading
   192     the instantiation string.  This fixes a bug that caused instantiated
   193     theorems to have too special types in some circumstances.
   194   - "where" permits explicit instantiations of type variables.
   195 
   196 * Calculation commands "moreover" and "also" no longer interfere with
   197   current facts ("this"), admitting arbitrary combinations with "then"
   198   and derived forms.
   199 
   200 * Locales:
   201   - Goal statements involving the context element "includes" no longer
   202     generate theorems with internal delta predicates (those ending on
   203     "_axioms") in the premise.
   204     Resolve particular premise with <locale>.intro to obtain old form.
   205   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   206     specification and "includes" elements in goal statement.
   207   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   208     [intro?] and [elim?] (respectively) by default.
   209   - Experimental command for instantiation of locales in proof contexts:
   210         instantiate <label>[<attrs>]: <loc>
   211     Instantiates locale <loc> and adds all its theorems to the current context
   212     taking into account their attributes.  Label and attrs are optional
   213     modifiers, like in theorem declarations.  If present, names of
   214     instantiated theorems are qualified with <label>, and the attributes
   215     <attrs> are applied after any attributes these theorems might have already.
   216       If the locale has assumptions, a chained fact of the form
   217     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   218     are derived.  The command does not support old-style locales declared
   219     with "locale (open)".
   220       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   221 
   222 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   223   (Isar) contexts.
   224 
   225 
   226 *** HOL ***
   227 
   228 * Proof import: new image HOL4 contains the imported library from
   229   the HOL4 system with about 2500 theorems. It is imported by
   230   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   231   can be used like any other Isabelle image.  See
   232   HOL/Import/HOL/README for more information.
   233 
   234 * Simplifier:
   235   - Much improved handling of linear and partial orders.
   236     Reasoners for linear and partial orders are set up for type classes
   237     "linorder" and "order" respectively, and are added to the default simpset
   238     as solvers.  This means that the simplifier can build transitivity chains
   239     to solve goals from the assumptions.
   240   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   241     of blast or auto after simplification become unnecessary because the goal
   242     is solved by simplification already.
   243 
   244 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   245     all proved in axiomatic type classes for semirings, rings and fields.
   246 
   247 * Numerics:
   248   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   249     now formalized using the Ring_and_Field theory mentioned above.
   250   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   251     than before, because now they are set up once in a generic manner.
   252   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   253     Look for the general versions in Ring_and_Field (and Power if they concern
   254     exponentiation).
   255 
   256 * Type "rat" of the rational numbers is now available in HOL-Complex.
   257 
   258 * Records:
   259   - Record types are now by default printed with their type abbreviation
   260     instead of the list of all field types. This can be configured via
   261     the reference "print_record_type_abbr".
   262   - Simproc "record_upd_simproc" for simplification of multiple updates added
   263     (not enabled by default).
   264   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   265     EX x. x = sel r to True (not enabled by default).
   266   - Tactic "record_split_simp_tac" to split and simplify records added.
   267 
   268 * 'specification' command added, allowing for definition by
   269   specification.  There is also an 'ax_specification' command that
   270   introduces the new constants axiomatically.
   271 
   272 * arith(_tac) is now able to generate counterexamples for reals as well.
   273 
   274 * HOL-Algebra: new locale "ring" for non-commutative rings.
   275 
   276 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   277   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   278 
   279 * HOL-Matrix: a first theory for matrices in HOL with an application of
   280   matrix theory to linear programming.
   281 
   282 * Unions and Intersections:
   283   The x-symbol output syntax of UN and INT has been changed
   284   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   285   i.e. the index formulae has become a subscript, like in normal math.
   286   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   287   The subscript version is also accepted as input syntax.
   288 
   289 * Unions and Intersections over Intervals:
   290   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   291   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   292   like in normal math, and corresponding versions for < and for intersection.
   293 
   294 * ML: the legacy theory structures Int and List have been removed. They had
   295   conflicted with ML Basis Library structures having the same names.
   296 
   297 * 'refute' command added to search for (finite) countermodels.  Only works
   298   for a fragment of HOL.  The installation of an external SAT solver is
   299   highly recommended.  See "HOL/Refute.thy" for details.
   300 
   301 * 'quickcheck' command: Allows to find counterexamples by evaluating
   302   formulae under an assignment of free variables to random values.
   303   In contrast to 'refute', it can deal with inductive datatypes,
   304   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   305   for examples.
   306 
   307 
   308 *** HOLCF ***
   309 
   310 * Streams now come with concatenation and are part of the HOLCF image
   311 
   312 
   313 
   314 New in Isabelle2003 (May 2003)
   315 ------------------------------
   316 
   317 *** General ***
   318 
   319 * Provers/simplifier:
   320 
   321   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   322     Assumptions are now subject to complete mutual simplification,
   323     not just from left to right. The simplifier now preserves
   324     the order of assumptions.
   325 
   326     Potential INCOMPATIBILITY:
   327 
   328     -- simp sometimes diverges where the old version did
   329        not, e.g. invoking simp on the goal
   330 
   331         [| P (f x); y = x; f x = f y |] ==> Q
   332 
   333        now gives rise to the infinite reduction sequence
   334 
   335         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   336 
   337        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   338        kind of problem.
   339 
   340     -- Tactics combining classical reasoner and simplification (such as auto)
   341        are also affected by this change, because many of them rely on
   342        simp. They may sometimes diverge as well or yield a different numbers
   343        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   344        in case of problems. Sometimes subsequent calls to the classical
   345        reasoner will fail because a preceeding call to the simplifier too
   346        eagerly simplified the goal, e.g. deleted redundant premises.
   347 
   348   - The simplifier trace now shows the names of the applied rewrite rules
   349 
   350   - You can limit the number of recursive invocations of the simplifier
   351     during conditional rewriting (where the simplifie tries to solve the
   352     conditions before applying the rewrite rule):
   353     ML "simp_depth_limit := n"
   354     where n is an integer. Thus you can force termination where previously
   355     the simplifier would diverge.
   356 
   357   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   358 
   359   - No longer aborts on failed congruence proof.  Instead, the
   360     congruence is ignored.
   361 
   362 * Pure: New generic framework for extracting programs from constructive
   363   proofs. See HOL/Extraction.thy for an example instantiation, as well
   364   as HOL/Extraction for some case studies.
   365 
   366 * Pure: The main goal of the proof state is no longer shown by default, only
   367 the subgoals. This behaviour is controlled by a new flag.
   368    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   369 (ML: Proof.show_main_goal).
   370 
   371 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   372 rules whose conclusion matches subgoal 1:
   373       PG menu: Isabelle/Isar -> Show me -> matching rules
   374 The rules are ordered by how closely they match the subgoal.
   375 In particular, rules that solve a subgoal outright are displayed first
   376 (or rather last, the way they are printed).
   377 (ML: ProofGeneral.print_intros())
   378 
   379 * Pure: New flag trace_unify_fail causes unification to print
   380 diagnostic information (PG: in trace buffer) when it fails. This is
   381 useful for figuring out why single step proofs like rule, erule or
   382 assumption failed.
   383 
   384 * Pure: Locale specifications now produce predicate definitions
   385 according to the body of text (covering assumptions modulo local
   386 definitions); predicate "loc_axioms" covers newly introduced text,
   387 while "loc" is cumulative wrt. all included locale expressions; the
   388 latter view is presented only on export into the global theory
   389 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   390 on the old view without predicates;
   391 
   392 * Pure: predefined locales "var" and "struct" are useful for sharing
   393 parameters (as in CASL, for example); just specify something like
   394 ``var x + var y + struct M'' as import;
   395 
   396 * Pure: improved thms_containing: proper indexing of facts instead of
   397 raw theorems; check validity of results wrt. current name space;
   398 include local facts of proof configuration (also covers active
   399 locales), cover fixed variables in index; may use "_" in term
   400 specification; an optional limit for the number of printed facts may
   401 be given (the default is 40);
   402 
   403 * Pure: disallow duplicate fact bindings within new-style theory files
   404 (batch-mode only);
   405 
   406 * Provers: improved induct method: assumptions introduced by case
   407 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   408 the goal statement); "foo" still refers to all facts collectively;
   409 
   410 * Provers: the function blast.overloaded has been removed: all constants
   411 are regarded as potentially overloaded, which improves robustness in exchange
   412 for slight decrease in efficiency;
   413 
   414 * Provers/linorder: New generic prover for transitivity reasoning over
   415 linear orders.  Note: this prover is not efficient!
   416 
   417 * Isar: preview of problems to finish 'show' now produce an error
   418 rather than just a warning (in interactive mode);
   419 
   420 
   421 *** HOL ***
   422 
   423 * arith(_tac)
   424 
   425  - Produces a counter example if it cannot prove a goal.
   426    Note that the counter example may be spurious if the goal is not a formula
   427    of quantifier-free linear arithmetic.
   428    In ProofGeneral the counter example appears in the trace buffer.
   429 
   430  - Knows about div k and mod k where k is a numeral of type nat or int.
   431 
   432  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   433    linear arithmetic fails. This takes account of quantifiers and divisibility.
   434    Presburger arithmetic can also be called explicitly via presburger(_tac).
   435 
   436 * simp's arithmetic capabilities have been enhanced a bit: it now
   437 takes ~= in premises into account (by performing a case split);
   438 
   439 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   440 are distributed over a sum of terms;
   441 
   442 * New tactic "trans_tac" and method "trans" instantiate
   443 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   444 "<=", "<" and "=").
   445 
   446 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   447 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   448 
   449 * 'typedef' command has new option "open" to suppress the set
   450 definition;
   451 
   452 * functions Min and Max on finite sets have been introduced (theory
   453 Finite_Set);
   454 
   455 * attribute [symmetric] now works for relations as well; it turns
   456 (x,y) : R^-1 into (y,x) : R, and vice versa;
   457 
   458 * induct over a !!-quantified statement (say !!x1..xn):
   459   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   460 
   461 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   462 %x. None. Warning: empty_def now refers to the previously hidden definition
   463 of the empty set.
   464 
   465 * Algebra: formalization of classical algebra.  Intended as base for
   466 any algebraic development in Isabelle.  Currently covers group theory
   467 (up to Sylow's theorem) and ring theory (Universal Property of
   468 Univariate Polynomials).  Contributions welcome;
   469 
   470 * GroupTheory: deleted, since its material has been moved to Algebra;
   471 
   472 * Complex: new directory of the complex numbers with numeric constants,
   473 nonstandard complex numbers, and some complex analysis, standard and
   474 nonstandard (Jacques Fleuriot);
   475 
   476 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   477 
   478 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   479 Fleuriot);
   480 
   481 * Real/HahnBanach: updated and adapted to locales;
   482 
   483 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   484 Gray and Kramer);
   485 
   486 * UNITY: added the Meier-Sanders theory of progress sets;
   487 
   488 * MicroJava: bytecode verifier and lightweight bytecode verifier
   489 as abstract algorithms, instantiated to the JVM;
   490 
   491 * Bali: Java source language formalization. Type system, operational
   492 semantics, axiomatic semantics. Supported language features:
   493 classes, interfaces, objects,virtual methods, static methods,
   494 static/instance fields, arrays, access modifiers, definite
   495 assignment, exceptions.
   496 
   497 
   498 *** ZF ***
   499 
   500 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   501 universe, etc.);
   502 
   503 * Main ZF: virtually all theories converted to new-style format;
   504 
   505 
   506 *** ML ***
   507 
   508 * Pure: Tactic.prove provides sane interface for internal proofs;
   509 omits the infamous "standard" operation, so this is more appropriate
   510 than prove_goalw_cterm in many situations (e.g. in simprocs);
   511 
   512 * Pure: improved error reporting of simprocs;
   513 
   514 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   515 up simprocs;
   516 
   517 
   518 *** Document preparation ***
   519 
   520 * uses \par instead of \\ for line breaks in theory text. This may
   521 shift some page breaks in large documents. To get the old behaviour
   522 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   523 
   524 * minimized dependencies of isabelle.sty and isabellesym.sty on
   525 other packages
   526 
   527 * \<euro> now needs package babel/greek instead of marvosym (which
   528 broke \Rightarrow)
   529 
   530 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   531 textcomp package)
   532 
   533 
   534 
   535 New in Isabelle2002 (March 2002)
   536 --------------------------------
   537 
   538 *** Document preparation ***
   539 
   540 * greatly simplified document preparation setup, including more
   541 graceful interpretation of isatool usedir -i/-d/-D options, and more
   542 instructive isatool mkdir; users should basically be able to get
   543 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   544 users may run a separate document processing stage manually like this:
   545 "isatool usedir -D output HOL Test && isatool document Test/output";
   546 
   547 * theory dependency graph may now be incorporated into documents;
   548 isatool usedir -g true will produce session_graph.eps/.pdf for use
   549 with \includegraphics of LaTeX;
   550 
   551 * proper spacing of consecutive markup elements, especially text
   552 blocks after section headings;
   553 
   554 * support bold style (for single symbols only), input syntax is like
   555 this: "\<^bold>\<alpha>" or "\<^bold>A";
   556 
   557 * \<bullet> is now output as bold \cdot by default, which looks much
   558 better in printed text;
   559 
   560 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   561 note that these symbols are currently unavailable in Proof General /
   562 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   563 
   564 * isatool latex no longer depends on changed TEXINPUTS, instead
   565 isatool document copies the Isabelle style files to the target
   566 location;
   567 
   568 
   569 *** Isar ***
   570 
   571 * Pure/Provers: improved proof by cases and induction;
   572   - 'case' command admits impromptu naming of parameters (such as
   573     "case (Suc n)");
   574   - 'induct' method divinates rule instantiation from the inductive
   575     claim; no longer requires excessive ?P bindings for proper
   576     instantiation of cases;
   577   - 'induct' method properly enumerates all possibilities of set/type
   578     rules; as a consequence facts may be also passed through *type*
   579     rules without further ado;
   580   - 'induct' method now derives symbolic cases from the *rulified*
   581     rule (before it used to rulify cases stemming from the internal
   582     atomized version); this means that the context of a non-atomic
   583     statement becomes is included in the hypothesis, avoiding the
   584     slightly cumbersome show "PROP ?case" form;
   585   - 'induct' may now use elim-style induction rules without chaining
   586     facts, using ``missing'' premises from the goal state; this allows
   587     rules stemming from inductive sets to be applied in unstructured
   588     scripts, while still benefitting from proper handling of non-atomic
   589     statements; NB: major inductive premises need to be put first, all
   590     the rest of the goal is passed through the induction;
   591   - 'induct' proper support for mutual induction involving non-atomic
   592     rule statements (uses the new concept of simultaneous goals, see
   593     below);
   594   - append all possible rule selections, but only use the first
   595     success (no backtracking);
   596   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   597   - undeclared rule case names default to numbers 1, 2, 3, ...;
   598   - added 'print_induct_rules' (covered by help item in recent Proof
   599     General versions);
   600   - moved induct/cases attributes to Pure, methods to Provers;
   601   - generic method setup instantiated for FOL and HOL;
   602 
   603 * Pure: support multiple simultaneous goal statements, for example
   604 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   605 meta-level mechanism, this acts as if several individual goals had
   606 been stated separately; in particular common proof methods need to be
   607 repeated in order to cover all claims; note that a single elimination
   608 step is *not* sufficient to establish the two conjunctions, so this
   609 fails:
   610 
   611   assume "A & B" then have A and B ..   (*".." fails*)
   612 
   613 better use "obtain" in situations as above; alternative refer to
   614 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   615 
   616 * Pure: proper integration with ``locales''; unlike the original
   617 version by Florian Kammüller, Isar locales package high-level proof
   618 contexts rather than raw logical ones (e.g. we admit to include
   619 attributes everywhere); operations on locales include merge and
   620 rename; support for implicit arguments (``structures''); simultaneous
   621 type-inference over imports and text; see also HOL/ex/Locales.thy for
   622 some examples;
   623 
   624 * Pure: the following commands have been ``localized'', supporting a
   625 target locale specification "(in name)": 'lemma', 'theorem',
   626 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   627 stored both within the locale and at the theory level (exported and
   628 qualified by the locale name);
   629 
   630 * Pure: theory goals may now be specified in ``long'' form, with
   631 ad-hoc contexts consisting of arbitrary locale elements. for example
   632 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   633 definitions may be given, too); the result is a meta-level rule with
   634 the context elements being discharged in the obvious way;
   635 
   636 * Pure: new proof command 'using' allows to augment currently used
   637 facts after a goal statement ('using' is syntactically analogous to
   638 'apply', but acts on the goal's facts only); this allows chained facts
   639 to be separated into parts given before and after a claim, as in
   640 ``from a and b have C using d and e <proof>'';
   641 
   642 * Pure: renamed "antecedent" case to "rule_context";
   643 
   644 * Pure: new 'judgment' command records explicit information about the
   645 object-logic embedding (used by several tools internally); no longer
   646 use hard-wired "Trueprop";
   647 
   648 * Pure: added 'corollary' command;
   649 
   650 * Pure: fixed 'token_translation' command;
   651 
   652 * Pure: removed obsolete 'exported' attribute;
   653 
   654 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   655 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   656 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   657 
   658 * Pure: method 'atomize' presents local goal premises as object-level
   659 statements (atomic meta-level propositions); setup controlled via
   660 rewrite rules declarations of 'atomize' attribute; example
   661 application: 'induct' method with proper rule statements in improper
   662 proof *scripts*;
   663 
   664 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   665 now consider the syntactic context of assumptions, giving a better
   666 chance to get type-inference of the arguments right (this is
   667 especially important for locales);
   668 
   669 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   670 mode;
   671 
   672 * Pure/obtain: the formal conclusion "thesis", being marked as
   673 ``internal'', may no longer be reference directly in the text;
   674 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   675 situations;
   676 
   677 * Pure: generic 'sym' attribute which declares a rule both as pure
   678 'elim?' and for the 'symmetric' operation;
   679 
   680 * Pure: marginal comments ``--'' may now occur just anywhere in the
   681 text; the fixed correlation with particular command syntax has been
   682 discontinued;
   683 
   684 * Pure: new method 'rules' is particularly well-suited for proof
   685 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   686 but often produces more compact proof terms with less detours;
   687 
   688 * Pure/Provers/classical: simplified integration with pure rule
   689 attributes and methods; the classical "intro?/elim?/dest?"
   690 declarations coincide with the pure ones; the "rule" method no longer
   691 includes classically swapped intros; "intro" and "elim" methods no
   692 longer pick rules from the context; also got rid of ML declarations
   693 AddXIs/AddXEs/AddXDs; all of this has some potential for
   694 INCOMPATIBILITY;
   695 
   696 * Provers/classical: attribute 'swapped' produces classical inversions
   697 of introduction rules;
   698 
   699 * Provers/simplifier: 'simplified' attribute may refer to explicit
   700 rules instead of full simplifier context; 'iff' attribute handles
   701 conditional rules;
   702 
   703 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   704 
   705 * HOL: 'recdef' now fails on unfinished automated proofs, use
   706 "(permissive)" option to recover old behavior;
   707 
   708 * HOL: 'inductive' no longer features separate (collective) attributes
   709 for 'intros' (was found too confusing);
   710 
   711 * HOL: properly declared induction rules less_induct and
   712 wf_induct_rule;
   713 
   714 
   715 *** HOL ***
   716 
   717 * HOL: moved over to sane numeral syntax; the new policy is as
   718 follows:
   719 
   720   - 0 and 1 are polymorphic constants, which are defined on any
   721   numeric type (nat, int, real etc.);
   722 
   723   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   724   binary representation internally;
   725 
   726   - type nat has special constructor Suc, and generally prefers Suc 0
   727   over 1::nat and Suc (Suc 0) over 2::nat;
   728 
   729 This change may cause significant problems of INCOMPATIBILITY; here
   730 are some hints on converting existing sources:
   731 
   732   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   733   entities, so expressions involving "-" (unary or binary minus) need
   734   to be spaced properly;
   735 
   736   - existing occurrences of "1" may need to be constraint "1::nat" or
   737   even replaced by Suc 0; similar for old "2";
   738 
   739   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   740 
   741   - remove all special provisions on numerals in proofs;
   742 
   743 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   744 representation (depends on bin_arith_simps in the default context);
   745 
   746 * HOL: symbolic syntax for x^2 (numeral 2);
   747 
   748 * HOL: the class of all HOL types is now called "type" rather than
   749 "term"; INCOMPATIBILITY, need to adapt references to this type class
   750 in axclass/classes, instance/arities, and (usually rare) occurrences
   751 in typings (of consts etc.); internally the class is called
   752 "HOL.type", ML programs should refer to HOLogic.typeS;
   753 
   754 * HOL/record package improvements:
   755   - new derived operations "fields" to build a partial record section,
   756     "extend" to promote a fixed record to a record scheme, and
   757     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   758     declared as simp by default;
   759   - shared operations ("more", "fields", etc.) now need to be always
   760     qualified) --- potential INCOMPATIBILITY;
   761   - removed "make_scheme" operations (use "make" with "extend") --
   762     INCOMPATIBILITY;
   763   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   764   - provides cases/induct rules for use with corresponding Isar
   765     methods (for concrete records, record schemes, concrete more
   766     parts, and schematic more parts -- in that order);
   767   - internal definitions directly based on a light-weight abstract
   768     theory of product types over typedef rather than datatype;
   769 
   770 * HOL: generic code generator for generating executable ML code from
   771 specifications; specific support for HOL constructs such as inductive
   772 datatypes and sets, as well as recursive functions; can be invoked
   773 via 'generate_code' theory section;
   774 
   775 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   776 
   777 * HOL: consolidated and renamed several theories.  In particular:
   778         Ord.thy has been absorbed into HOL.thy
   779         String.thy has been absorbed into List.thy
   780 
   781 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   782 (beware of argument permutation!);
   783 
   784 * HOL: linorder_less_split superseded by linorder_cases;
   785 
   786 * HOL/List: "nodups" renamed to "distinct";
   787 
   788 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   789 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   790   - Ex_def has changed, now need to use some_eq_ex
   791 
   792 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   793 in this (rare) case use:
   794 
   795   delSWrapper "split_all_tac"
   796   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   797 
   798 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   799 MAY FAIL;
   800 
   801 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   802 Isabelle's type classes, ^ on functions and relations has too general
   803 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   804 necessary to attach explicit type constraints;
   805 
   806 * HOL/Relation: the prefix name of the infix "O" has been changed from
   807 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   808 renamed accordingly (eg "compI" -> "rel_compI").
   809 
   810 * HOL: syntax translations now work properly with numerals and records
   811 expressions;
   812 
   813 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   814 of "lam" -- INCOMPATIBILITY;
   815 
   816 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   817 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   818 renamed "Product_Type.unit";
   819 
   820 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   821 
   822 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   823 the "cases" method);
   824 
   825 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   826 Florian Kammüller);
   827 
   828 * HOL/IMP: updated and converted to new-style theory format; several
   829 parts turned into readable document, with proper Isar proof texts and
   830 some explanations (by Gerwin Klein);
   831 
   832 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   833 
   834 * HOL-Hyperreal is now a logic image;
   835 
   836 
   837 *** HOLCF ***
   838 
   839 * Isar: consts/constdefs supports mixfix syntax for continuous
   840 operations;
   841 
   842 * Isar: domain package adapted to new-style theory format, e.g. see
   843 HOLCF/ex/Dnat.thy;
   844 
   845 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   846 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   847 lift.induct_tac, always use UU instead of Undef;
   848 
   849 * HOLCF/IMP: updated and converted to new-style theory;
   850 
   851 
   852 *** ZF ***
   853 
   854 * Isar: proper integration of logic-specific tools and packages,
   855 including theory commands '(co)inductive', '(co)datatype',
   856 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   857 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   858 
   859 * theory Main no longer includes AC; for the Axiom of Choice, base
   860 your theory on Main_ZFC;
   861 
   862 * the integer library now covers quotients and remainders, with many
   863 laws relating division to addition, multiplication, etc.;
   864 
   865 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   866 typeless version of the formalism;
   867 
   868 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   869 format;
   870 
   871 * ZF/Induct: new directory for examples of inductive definitions,
   872 including theory Multiset for multiset orderings; converted to
   873 new-style theory format;
   874 
   875 * ZF: many new theorems about lists, ordinals, etc.;
   876 
   877 
   878 *** General ***
   879 
   880 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   881 variable proof controls level of detail: 0 = no proofs (only oracle
   882 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   883 also ref manual for further ML interfaces;
   884 
   885 * Pure/axclass: removed obsolete ML interface
   886 goal_subclass/goal_arity;
   887 
   888 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   889 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   890 separate tokens, so expressions involving minus need to be spaced
   891 properly;
   892 
   893 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   894 rather than "infixl" or "infixr";
   895 
   896 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   897 sort constraint specifications in type inference; e.g. "x::_::foo"
   898 ensures that the type of "x" is of sort "foo" (but not necessarily a
   899 type variable);
   900 
   901 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   902 control output of nested => (types); the default behavior is
   903 "type_brackets";
   904 
   905 * Pure/syntax: builtin parse translation for "_constify" turns valued
   906 tokens into AST constants;
   907 
   908 * Pure/syntax: prefer later declarations of translations and print
   909 translation functions; potential INCOMPATIBILITY: need to reverse
   910 multiple declarations for same syntax element constant;
   911 
   912 * Pure/show_hyps reset by default (in accordance to existing Isar
   913 practice);
   914 
   915 * Provers/classical: renamed addaltern to addafter, addSaltern to
   916 addSafter;
   917 
   918 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   919 as well;
   920 
   921 * system: tested support for MacOS X; should be able to get Isabelle +
   922 Proof General to work in a plain Terminal after installing Poly/ML
   923 (e.g. from the Isabelle distribution area) and GNU bash alone
   924 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   925 support requires further installations, e.g. from
   926 http://fink.sourceforge.net/);
   927 
   928 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   929 
   930 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   931 of 40 MB), cf. ML_OPTIONS;
   932 
   933 * system: Proof General keywords specification is now part of the
   934 Isabelle distribution (see etc/isar-keywords.el);
   935 
   936 * system: support for persistent Proof General sessions (refrain from
   937 outdating all loaded theories on startup); user may create writable
   938 logic images like this: ``isabelle -q HOL Test'';
   939 
   940 * system: smart selection of Isabelle process versus Isabelle
   941 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   942 run both "isabelle" and "Isabelle" even if file names are badly
   943 damaged (executable inspects the case of the first letter of its own
   944 name); added separate "isabelle-process" and "isabelle-interface";
   945 
   946 * system: refrain from any attempt at filtering input streams; no
   947 longer support ``8bit'' encoding of old isabelle font, instead proper
   948 iso-latin characters may now be used; the related isatools
   949 "symbolinput" and "nonascii" have disappeared as well;
   950 
   951 * system: removed old "xterm" interface (the print modes "xterm" and
   952 "xterm_color" are still available for direct use in a suitable
   953 terminal);
   954 
   955 
   956 
   957 New in Isabelle99-2 (February 2001)
   958 -----------------------------------
   959 
   960 *** Overview of INCOMPATIBILITIES ***
   961 
   962 * HOL: please note that theories in the Library and elsewhere often use the
   963 new-style (Isar) format; to refer to their theorems in an ML script you must
   964 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   965 
   966 * HOL: inductive package no longer splits induction rule aggressively,
   967 but only as far as specified by the introductions given; the old
   968 format may be recovered via ML function complete_split_rule or attribute
   969 'split_rule (complete)';
   970 
   971 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   972 gfp_Tarski to gfp_unfold;
   973 
   974 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   975 
   976 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   977 relation); infix "^^" has been renamed "``"; infix "``" has been
   978 renamed "`"; "univalent" has been renamed "single_valued";
   979 
   980 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   981 operation;
   982 
   983 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   984 
   985 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   986 
   987 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   988 consequence, it is no longer monotonic wrt. the local goal context
   989 (which is now passed through the inductive cases);
   990 
   991 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   992 \<gg> to \<ggreater>;
   993 
   994 
   995 *** Document preparation ***
   996 
   997 * \isabellestyle{NAME} selects version of Isabelle output (currently
   998 available: are "it" for near math-mode best-style output, "sl" for
   999 slanted text style, and "tt" for plain type-writer; if no
  1000 \isabellestyle command is given, output is according to slanted
  1001 type-writer);
  1002 
  1003 * support sub/super scripts (for single symbols only), input syntax is
  1004 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1005 
  1006 * some more standard symbols; see Appendix A of the system manual for
  1007 the complete list of symbols defined in isabellesym.sty;
  1008 
  1009 * improved isabelle style files; more abstract symbol implementation
  1010 (should now use \isamath{...} and \isatext{...} in custom symbol
  1011 definitions);
  1012 
  1013 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1014 state; Note that presentation of goal states does not conform to
  1015 actual human-readable proof documents.  Please do not include goal
  1016 states into document output unless you really know what you are doing!
  1017 
  1018 * proper indentation of antiquoted output with proportional LaTeX
  1019 fonts;
  1020 
  1021 * no_document ML operator temporarily disables LaTeX document
  1022 generation;
  1023 
  1024 * isatool unsymbolize tunes sources for plain ASCII communication;
  1025 
  1026 
  1027 *** Isar ***
  1028 
  1029 * Pure: Isar now suffers initial goal statements to contain unbound
  1030 schematic variables (this does not conform to actual readable proof
  1031 documents, due to unpredictable outcome and non-compositional proof
  1032 checking); users who know what they are doing may use schematic goals
  1033 for Prolog-style synthesis of proven results;
  1034 
  1035 * Pure: assumption method (an implicit finishing) now handles actual
  1036 rules as well;
  1037 
  1038 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1039 initial goal, declare "that" only as Pure intro (only for single
  1040 steps); the "that" rule assumption may now be involved in implicit
  1041 finishing, thus ".." becomes a feasible for trivial obtains;
  1042 
  1043 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1044 instance proofs may be performed by "..";
  1045 
  1046 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1047 statements as well;
  1048 
  1049 * Pure: more robust selection of calculational rules;
  1050 
  1051 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1052 rule (as well as the assumption rule);
  1053 
  1054 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1055 lemmas, using the graph browser tool;
  1056 
  1057 * Pure: predict failure of "show" in interactive mode;
  1058 
  1059 * Pure: 'thms_containing' now takes actual terms as arguments;
  1060 
  1061 * HOL: improved method 'induct' --- now handles non-atomic goals
  1062 (potential INCOMPATIBILITY); tuned error handling;
  1063 
  1064 * HOL: cases and induct rules now provide explicit hints about the
  1065 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1066 any remaining facts are inserted into the goal verbatim;
  1067 
  1068 * HOL: local contexts (aka cases) may now contain term bindings as
  1069 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1070 the result to be shown in each case;
  1071 
  1072 * HOL: added 'recdef_tc' command;
  1073 
  1074 * isatool convert assists in eliminating legacy ML scripts;
  1075 
  1076 
  1077 *** HOL ***
  1078 
  1079 * HOL/Library: a collection of generic theories to be used together
  1080 with main HOL; the theory loader path already includes this directory
  1081 by default; the following existing theories have been moved here:
  1082 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1083 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1084 
  1085 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1086 modelling and verification task performed in Isabelle/HOL +
  1087 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1088 
  1089 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1090 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1091 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1092 'domain', this makes the theory consistent with mathematical
  1093 literature;
  1094 
  1095 * HOL basics: added overloaded operations "inverse" and "divide"
  1096 (infix "/"), syntax for generic "abs" operation, generic summation
  1097 operator \<Sum>;
  1098 
  1099 * HOL/typedef: simplified package, provide more useful rules (see also
  1100 HOL/subset.thy);
  1101 
  1102 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1103 now expressed as a proper nested rule (old-style tactic scripts may
  1104 require atomize_strip_tac to cope with non-atomic premises);
  1105 
  1106 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1107 to "split_conv" (old name still available for compatibility);
  1108 
  1109 * HOL: improved concrete syntax for strings (e.g. allows translation
  1110 rules with string literals);
  1111 
  1112 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1113  and Fleuriot's mechanization of analysis, including the transcendental
  1114  functions for the reals;
  1115 
  1116 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1117 
  1118 
  1119 *** CTT ***
  1120 
  1121 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1122 "lam" is displayed as TWO lambda-symbols
  1123 
  1124 * CTT: theory Main now available, containing everything (that is, Bool
  1125 and Arith);
  1126 
  1127 
  1128 *** General ***
  1129 
  1130 * Pure: the Simplifier has been implemented properly as a derived rule
  1131 outside of the actual kernel (at last!); the overall performance
  1132 penalty in practical applications is about 50%, while reliability of
  1133 the Isabelle inference kernel has been greatly improved;
  1134 
  1135 * print modes "brackets" and "no_brackets" control output of nested =>
  1136 (types) and ==> (props); the default behaviour is "brackets";
  1137 
  1138 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1139 as assumptions as well;
  1140 
  1141 * system: support Poly/ML 4.0;
  1142 
  1143 * system: isatool install handles KDE version 1 or 2;
  1144 
  1145 
  1146 
  1147 New in Isabelle99-1 (October 2000)
  1148 ----------------------------------
  1149 
  1150 *** Overview of INCOMPATIBILITIES ***
  1151 
  1152 * HOL: simplification of natural numbers is much changed; to partly
  1153 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1154 issue the following ML commands:
  1155 
  1156   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1157   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1158 
  1159 * HOL: simplification no longer dives into case-expressions; this is
  1160 controlled by "t.weak_case_cong" for each datatype t;
  1161 
  1162 * HOL: nat_less_induct renamed to less_induct;
  1163 
  1164 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1165 fixsome to patch .thy and .ML sources automatically;
  1166 
  1167   select_equality  -> some_equality
  1168   select_eq_Ex     -> some_eq_ex
  1169   selectI2EX       -> someI2_ex
  1170   selectI2         -> someI2
  1171   selectI          -> someI
  1172   select1_equality -> some1_equality
  1173   Eps_sym_eq       -> some_sym_eq_trivial
  1174   Eps_eq           -> some_eq_trivial
  1175 
  1176 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1177 
  1178 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1179 instead);
  1180 
  1181 * HOL: the recursion equations generated by 'recdef' are now called
  1182 f.simps instead of f.rules;
  1183 
  1184 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1185 
  1186 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1187 sometimes be needed;
  1188 
  1189 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1190 
  1191 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1192 
  1193 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1194 product is now "<*>" instead of "Times"; the lexicographic product is
  1195 now "<*lex*>" instead of "**";
  1196 
  1197 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1198 of main HOL, but was unused); better use HOL's datatype package;
  1199 
  1200 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1201 the old syntax may be recovered as follows:
  1202 
  1203   syntax (symbols)
  1204     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1205       (infixl "\\<oplus>" 100)
  1206 
  1207 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1208 
  1209 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1210 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1211 internally;
  1212 
  1213 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1214 changed from A/r to A//r;
  1215 
  1216 * ZF: new treatment of arithmetic (nat & int) may break some old
  1217 proofs;
  1218 
  1219 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1220 rulify -> rule_format, elimify -> elim_format, ...);
  1221 
  1222 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1223 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1224 should have to change intro!! to intro? only); replaced "delrule" by
  1225 "rule del";
  1226 
  1227 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1228 
  1229 * Provers: strengthened force_tac by using new first_best_tac;
  1230 
  1231 * LaTeX document preparation: several changes of isabelle.sty (see
  1232 lib/texinputs);
  1233 
  1234 
  1235 *** Document preparation ***
  1236 
  1237 * formal comments (text blocks etc.) in new-style theories may now
  1238 contain antiquotations of thm/prop/term/typ/text to be presented
  1239 according to latex print mode; concrete syntax is like this:
  1240 @{term[show_types] "f(x) = a + x"};
  1241 
  1242 * isatool mkdir provides easy setup of Isabelle session directories,
  1243 including proper document sources;
  1244 
  1245 * generated LaTeX sources are now deleted after successful run
  1246 (isatool document -c); may retain a copy somewhere else via -D option
  1247 of isatool usedir;
  1248 
  1249 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1250 style files, achieving self-contained LaTeX sources and simplifying
  1251 LaTeX debugging;
  1252 
  1253 * old-style theories now produce (crude) LaTeX output as well;
  1254 
  1255 * browser info session directories are now self-contained (may be put
  1256 on WWW server seperately); improved graphs of nested sessions; removed
  1257 graph for 'all sessions';
  1258 
  1259 * several improvements in isabelle style files; \isabellestyle{it}
  1260 produces fake math mode output; \isamarkupheader is now \section by
  1261 default; see lib/texinputs/isabelle.sty etc.;
  1262 
  1263 
  1264 *** Isar ***
  1265 
  1266 * Isar/Pure: local results and corresponding term bindings are now
  1267 subject to Hindley-Milner polymorphism (similar to ML); this
  1268 accommodates incremental type-inference very nicely;
  1269 
  1270 * Isar/Pure: new derived language element 'obtain' supports
  1271 generalized existence reasoning;
  1272 
  1273 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1274 support accumulation of results, without applying any rules yet;
  1275 useful to collect intermediate results without explicit name
  1276 references, and for use with transitivity rules with more than 2
  1277 premises;
  1278 
  1279 * Isar/Pure: scalable support for case-analysis type proofs: new
  1280 'case' language element refers to local contexts symbolically, as
  1281 produced by certain proof methods; internally, case names are attached
  1282 to theorems as "tags";
  1283 
  1284 * Isar/Pure: theory command 'hide' removes declarations from
  1285 class/type/const name spaces;
  1286 
  1287 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1288 indicate potential overloading;
  1289 
  1290 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1291 
  1292 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1293 "{a,b,c}" instead of {a,b,c};
  1294 
  1295 * Isar/Pure now provides its own version of intro/elim/dest
  1296 attributes; useful for building new logics, but beware of confusion
  1297 with the version in Provers/classical;
  1298 
  1299 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1300 case name 'antecedent';
  1301 
  1302 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1303 to the current context is now done automatically);
  1304 
  1305 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1306 for definining proof methods in ML;
  1307 
  1308 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1309 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1310 most cases, one should have to change intro!! to intro? only);
  1311 replaced "delrule" by "rule del";
  1312 
  1313 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1314 'symmetric' attribute (the latter supercedes [RS sym]);
  1315 
  1316 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1317 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1318 well (including splits);
  1319 
  1320 * Isar/Provers: Simplifier and Classical methods now support all kind
  1321 of modifiers used in the past, including 'cong', 'iff', etc.
  1322 
  1323 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1324 of Simplifier and Classical reasoner);
  1325 
  1326 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1327 now support named cases; major packages (inductive, datatype, primrec,
  1328 recdef) support case names and properly name parameters;
  1329 
  1330 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1331 monotonicity conditions are extracted to be proven at end of
  1332 calculations;
  1333 
  1334 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1335 method anyway;
  1336 
  1337 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1338 split_if split_if_asm; datatype package provides theorems foo.splits =
  1339 foo.split foo.split_asm for each datatype;
  1340 
  1341 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1342 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1343 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1344 use "(cases (simplified))" method in proper proof texts);
  1345 
  1346 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1347 
  1348 * Isar: names of theorems etc. may be natural numbers as well;
  1349 
  1350 * Isar: 'pr' command: optional arguments for goals_limit and
  1351 ProofContext.prems_limit; no longer prints theory contexts, but only
  1352 proof states;
  1353 
  1354 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1355 additional print modes to be specified; e.g. "pr(latex)" will print
  1356 proof state according to the Isabelle LaTeX style;
  1357 
  1358 * Isar: improved support for emulating tactic scripts, including proof
  1359 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1360 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1361 (for HOL datatypes);
  1362 
  1363 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1364 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1365 'proof method scripts' have to be in depth-first order;
  1366 
  1367 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1368 
  1369 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1370 should instead use individual commands for printing items
  1371 (print_commands, print_methods etc.);
  1372 
  1373 * Isar: added 'nothing' --- the empty list of theorems;
  1374 
  1375 
  1376 *** HOL ***
  1377 
  1378 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1379 corresponding virtual machine and a specification of its bytecode
  1380 verifier and a lightweight bytecode verifier, including proofs of
  1381 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1382 Cornelia Pusch (see also the homepage of project Bali at
  1383 http://isabelle.in.tum.de/Bali/);
  1384 
  1385 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1386 Clemens Ballarin;
  1387 
  1388 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1389 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1390 Rasmussen;
  1391 
  1392 * HOL/Lattice: fundamental concepts of lattice theory and order
  1393 structures, including duals, properties of bounds versus algebraic
  1394 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1395 Theorem for complete lattices etc.; may also serve as a demonstration
  1396 for abstract algebraic reasoning using axiomatic type classes, and
  1397 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1398 
  1399 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1400 von Oheimb;
  1401 
  1402 * HOL/IMPP: extension of IMP with local variables and mutually
  1403 recursive procedures, by David von Oheimb;
  1404 
  1405 * HOL/Lambda: converted into new-style theory and document;
  1406 
  1407 * HOL/ex/Multiquote: example of multiple nested quotations and
  1408 anti-quotations -- basically a generalized version of de-Bruijn
  1409 representation; very useful in avoiding lifting of operations;
  1410 
  1411 * HOL/record: added general record equality rule to simpset; fixed
  1412 select-update simplification procedure to handle extended records as
  1413 well; admit "r" as field name;
  1414 
  1415 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1416 other numeric types and also as the identity of groups, rings, etc.;
  1417 
  1418 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1419 Types nat and int belong to this axclass;
  1420 
  1421 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1422    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1423    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1424   two terms #m*u and #n*u are replaced by #(m+n)*u
  1425     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1426   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1427     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1428 
  1429 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1430 powerful prover for predicate logic but knows nothing of clasets; see
  1431 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1432 
  1433 * HOL: new version of "case_tac" subsumes both boolean case split and
  1434 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1435 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1436 
  1437 * HOL: simplification no longer dives into case-expressions: only the
  1438 selector expression is simplified, but not the remaining arms; to
  1439 enable full simplification of case-expressions for datatype t, you may
  1440 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1441 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1442 
  1443 * HOL/recdef: the recursion equations generated by 'recdef' for
  1444 function 'f' are now called f.simps instead of f.rules; if all
  1445 termination conditions are proved automatically, these simplification
  1446 rules are added to the simpset, as in primrec; rules may be named
  1447 individually as well, resulting in a separate list of theorems for
  1448 each equation;
  1449 
  1450 * HOL/While is a new theory that provides a while-combinator. It
  1451 permits the definition of tail-recursive functions without the
  1452 provision of a termination measure. The latter is necessary once the
  1453 invariant proof rule for while is applied.
  1454 
  1455 * HOL: new (overloaded) notation for the set of elements below/above
  1456 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1457 
  1458 * HOL: theorems impI, allI, ballI bound as "strip";
  1459 
  1460 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1461 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1462 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1463 
  1464 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1465 
  1466 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1467 main HOL, but was unused);
  1468 
  1469 * HOL: fewer consts declared as global (e.g. have to refer to
  1470 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1471 
  1472 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1473 in case of overlap with user translations (e.g. judgements over
  1474 tuples); (note that the underlying logical represenation is still
  1475 bogus);
  1476 
  1477 
  1478 *** ZF ***
  1479 
  1480 * ZF: simplification automatically cancels common terms in arithmetic
  1481 expressions over nat and int;
  1482 
  1483 * ZF: new treatment of nat to minimize type-checking: all operators
  1484 coerce their operands to a natural number using the function natify,
  1485 making the algebraic laws unconditional;
  1486 
  1487 * ZF: as above, for int: operators coerce their operands to an integer
  1488 using the function intify;
  1489 
  1490 * ZF: the integer library now contains many of the usual laws for the
  1491 orderings, including $<=, and monotonicity laws for $+ and $*;
  1492 
  1493 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1494 simplification;
  1495 
  1496 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1497 to the simplifier and classical reasoner simultaneously;
  1498 
  1499 
  1500 *** General ***
  1501 
  1502 * Provers: blast_tac now handles actual object-logic rules as
  1503 assumptions; note that auto_tac uses blast_tac internally as well;
  1504 
  1505 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1506 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1507 
  1508 * Provers: delrules now handles destruct rules as well (no longer need
  1509 explicit make_elim);
  1510 
  1511 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1512   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1513 use instead the strong form,
  1514   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1515 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1516 from destruct-rules;
  1517 
  1518 * Provers: Simplifier.easy_setup provides a fast path to basic
  1519 Simplifier setup for new object-logics;
  1520 
  1521 * Pure: AST translation rules no longer require constant head on LHS;
  1522 
  1523 * Pure: improved name spaces: ambiguous output is qualified; support
  1524 for hiding of names;
  1525 
  1526 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1527 XSYMBOL_HOME; no longer need to do manual configuration in most
  1528 situations;
  1529 
  1530 * system: compression of ML heaps images may now be controlled via -c
  1531 option of isabelle and isatool usedir (currently only observed by
  1532 Poly/ML);
  1533 
  1534 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1535 useful for remote X11);
  1536 
  1537 * system: provide TAGS file for Isabelle sources;
  1538 
  1539 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1540 order;
  1541 
  1542 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1543 timing flag supersedes proof_timing and Toplevel.trace;
  1544 
  1545 * ML: new combinators |>> and |>>> for incremental transformations
  1546 with secondary results (e.g. certain theory extensions):
  1547 
  1548 * ML: PureThy.add_defs gets additional argument to indicate potential
  1549 overloading (usually false);
  1550 
  1551 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1552 results;
  1553 
  1554 
  1555 
  1556 New in Isabelle99 (October 1999)
  1557 --------------------------------
  1558 
  1559 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1560 
  1561 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1562 are no longer simplified.  (This allows the simplifier to unfold recursive
  1563 functional programs.)  To restore the old behaviour, declare
  1564 
  1565     Delcongs [if_weak_cong];
  1566 
  1567 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1568 complement;
  1569 
  1570 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1571 
  1572 * HOL/datatype: mutual_induct_tac no longer exists --
  1573   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1574 
  1575 * HOL/typedef: fixed type inference for representing set; type
  1576 arguments now have to occur explicitly on the rhs as type constraints;
  1577 
  1578 * ZF: The con_defs part of an inductive definition may no longer refer
  1579 to constants declared in the same theory;
  1580 
  1581 * HOL, ZF: the function mk_cases, generated by the inductive
  1582 definition package, has lost an argument.  To simplify its result, it
  1583 uses the default simpset instead of a supplied list of theorems.
  1584 
  1585 * HOL/List: the constructors of type list are now Nil and Cons;
  1586 
  1587 * Simplifier: the type of the infix ML functions
  1588         setSSolver addSSolver setSolver addSolver
  1589 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1590 for packaging solvers. A solver is created via
  1591         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1592 where the string argument is only a comment.
  1593 
  1594 
  1595 *** Proof tools ***
  1596 
  1597 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1598 decision procedure for linear arithmetic. Currently it is used for
  1599 types `nat', `int', and `real' in HOL (see below); it can, should and
  1600 will be instantiated for other types and logics as well.
  1601 
  1602 * The simplifier now accepts rewrite rules with flexible heads, eg
  1603      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1604   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1605   matching.
  1606 
  1607 
  1608 *** General ***
  1609 
  1610 * New Isabelle/Isar subsystem provides an alternative to traditional
  1611 tactical theorem proving; together with the ProofGeneral/isar user
  1612 interface it offers an interactive environment for developing human
  1613 readable proof documents (Isar == Intelligible semi-automated
  1614 reasoning); for further information see isatool doc isar-ref,
  1615 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1616 
  1617 * improved and simplified presentation of theories: better HTML markup
  1618 (including colors), graph views in several sizes; isatool usedir now
  1619 provides a proper interface for user theories (via -P option); actual
  1620 document preparation based on (PDF)LaTeX is available as well (for
  1621 new-style theories only); see isatool doc system for more information;
  1622 
  1623 * native support for Proof General, both for classic Isabelle and
  1624 Isabelle/Isar;
  1625 
  1626 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1627 using the graph browser tool;
  1628 
  1629 * Isabelle manuals now also available as PDF;
  1630 
  1631 * theory loader rewritten from scratch (may not be fully
  1632 bug-compatible); old loadpath variable has been replaced by show_path,
  1633 add_path, del_path, reset_path functions; new operations such as
  1634 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1635 isatool doc ref);
  1636 
  1637 * improved isatool install: option -k creates KDE application icon,
  1638 option -p DIR installs standalone binaries;
  1639 
  1640 * added ML_PLATFORM setting (useful for cross-platform installations);
  1641 more robust handling of platform specific ML images for SML/NJ;
  1642 
  1643 * the settings environment is now statically scoped, i.e. it is never
  1644 created again in sub-processes invoked from isabelle, isatool, or
  1645 Isabelle;
  1646 
  1647 * path element specification '~~' refers to '$ISABELLE_HOME';
  1648 
  1649 * in locales, the "assumes" and "defines" parts may be omitted if
  1650 empty;
  1651 
  1652 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1653 long arrows);
  1654 
  1655 * new print_mode "HTML";
  1656 
  1657 * new flag show_tags controls display of tags of theorems (which are
  1658 basically just comments that may be attached by some tools);
  1659 
  1660 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1661 mode and goal output format:
  1662 
  1663 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1664 244c244
  1665 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1666 ---
  1667 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1668 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1669 181c181
  1670 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1671 ---
  1672 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1673 
  1674 * function bind_thms stores lists of theorems (cf. bind_thm);
  1675 
  1676 * new shorthand tactics ftac, eatac, datac, fatac;
  1677 
  1678 * qed (and friends) now accept "" as result name; in that case the
  1679 theorem is not stored, but proper checks and presentation of the
  1680 result still apply;
  1681 
  1682 * theorem database now also indexes constants "Trueprop", "all",
  1683 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1684 
  1685 
  1686 *** HOL ***
  1687 
  1688 ** HOL arithmetic **
  1689 
  1690 * There are now decision procedures for linear arithmetic over nat and
  1691 int:
  1692 
  1693 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1694 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1695 are treated as atomic; subformulae not involving type `nat' or `int'
  1696 are ignored; quantified subformulae are ignored unless they are
  1697 positive universal or negative existential. The tactic has to be
  1698 invoked by hand and can be a little bit slow. In particular, the
  1699 running time is exponential in the number of occurrences of `min' and
  1700 `max', and `-' on `nat'.
  1701 
  1702 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1703 (negated) (in)equalities among the premises and the conclusion into
  1704 account (i.e. no compound formulae) and does not know about `min' and
  1705 `max', and `-' on `nat'. It is fast and is used automatically by the
  1706 simplifier.
  1707 
  1708 NB: At the moment, these decision procedures do not cope with mixed
  1709 nat/int formulae where the two parts interact, such as `m < n ==>
  1710 int(m) < int(n)'.
  1711 
  1712 * HOL/Numeral provides a generic theory of numerals (encoded
  1713 efficiently as bit strings); setup for types nat/int/real is in place;
  1714 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1715 int, existing theories and proof scripts may require a few additional
  1716 type constraints;
  1717 
  1718 * integer division and remainder can now be performed on constant
  1719 arguments;
  1720 
  1721 * many properties of integer multiplication, division and remainder
  1722 are now available;
  1723 
  1724 * An interface to the Stanford Validity Checker (SVC) is available through the
  1725 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1726 are proved automatically.  SVC must be installed separately, and its results
  1727 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1728 invocation of the underlying oracle).  For SVC see
  1729   http://verify.stanford.edu/SVC
  1730 
  1731 * IsaMakefile: the HOL-Real target now builds an actual image;
  1732 
  1733 
  1734 ** HOL misc **
  1735 
  1736 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1737 (in Isabelle/Isar) -- by Gertrud Bauer;
  1738 
  1739 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1740 analysis for assembly languages with subtypes;
  1741 
  1742 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1743 -- avoids syntactic ambiguities and treats state, transition, and
  1744 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1745 changed syntax and (many) tactics;
  1746 
  1747 * HOL/inductive: Now also handles more general introduction rules such
  1748   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1749   theorems are now maintained within the theory (maintained via the
  1750   "mono" attribute);
  1751 
  1752 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1753   (using function types) such as
  1754 
  1755   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1756 
  1757 * HOL/record: record_simproc (part of the default simpset) takes care
  1758 of selectors applied to updated records; record_split_tac is no longer
  1759 part of the default claset; update_defs may now be removed from the
  1760 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1761 
  1762   claset_ref () := claset() addSWrapper record_split_wrapper;
  1763   Delsimprocs [record_simproc]
  1764 
  1765 * HOL/typedef: fixed type inference for representing set; type
  1766 arguments now have to occur explicitly on the rhs as type constraints;
  1767 
  1768 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1769 names rather than an ML expression;
  1770 
  1771 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1772 supplied later.  Program schemes can be defined, such as
  1773     "While B C s = (if B s then While B C (C s) else s)"
  1774 where the well-founded relation can be chosen after B and C have been given.
  1775 
  1776 * HOL/List: the constructors of type list are now Nil and Cons;
  1777 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1778 course, ML tools referring to List.list.op # etc. have to be adapted;
  1779 
  1780 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1781 disabled by default; run isabelle with option -m HOL to get back to
  1782 the original Gordon/HOL-style output;
  1783 
  1784 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1785 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1786 
  1787 * HOL basic syntax simplified (more orthogonal): all variants of
  1788 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1789 Eps operator is provided as well: "SOME x. P[x]";
  1790 
  1791 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1792 
  1793 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1794 thus available for user theories;
  1795 
  1796 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1797 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1798 time;
  1799 
  1800 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1801 several times and then mp;
  1802 
  1803 
  1804 *** LK ***
  1805 
  1806 * the notation <<...>> is now available as a notation for sequences of
  1807 formulas;
  1808 
  1809 * the simplifier is now installed
  1810 
  1811 * the axiom system has been generalized (thanks to Soren Heilmann)
  1812 
  1813 * the classical reasoner now has a default rule database
  1814 
  1815 
  1816 *** ZF ***
  1817 
  1818 * new primrec section allows primitive recursive functions to be given
  1819 directly (as in HOL) over datatypes and the natural numbers;
  1820 
  1821 * new tactics induct_tac and exhaust_tac for induction (or case
  1822 analysis) over datatypes and the natural numbers;
  1823 
  1824 * the datatype declaration of type T now defines the recursor T_rec;
  1825 
  1826 * simplification automatically does freeness reasoning for datatype
  1827 constructors;
  1828 
  1829 * automatic type-inference, with AddTCs command to insert new
  1830 type-checking rules;
  1831 
  1832 * datatype introduction rules are now added as Safe Introduction rules
  1833 to the claset;
  1834 
  1835 * the syntax "if P then x else y" is now available in addition to
  1836 if(P,x,y);
  1837 
  1838 
  1839 *** Internal programming interfaces ***
  1840 
  1841 * tuned simplifier trace output; new flag debug_simp;
  1842 
  1843 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1844 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1845 
  1846 * AxClass.axclass_tac lost the theory argument;
  1847 
  1848 * tuned current_goals_markers semantics: begin / end goal avoids
  1849 printing empty lines;
  1850 
  1851 * removed prs and prs_fn hook, which was broken because it did not
  1852 include \n in its semantics, forcing writeln to add one
  1853 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1854 string -> unit if you really want to output text without newline;
  1855 
  1856 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1857 plain output, interface builders may have to enable 'isabelle_font'
  1858 mode to get Isabelle font glyphs as before;
  1859 
  1860 * refined token_translation interface; INCOMPATIBILITY: output length
  1861 now of type real instead of int;
  1862 
  1863 * theory loader actions may be traced via new ThyInfo.add_hook
  1864 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1865 your own database of information attached to *whole* theories -- as
  1866 opposed to intra-theory data slots offered via TheoryDataFun;
  1867 
  1868 * proper handling of dangling sort hypotheses (at last!);
  1869 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1870 extra sort hypotheses that can be witnessed from the type signature;
  1871 the force_strip_shyps flag is gone, any remaining shyps are simply
  1872 left in the theorem (with a warning issued by strip_shyps_warning);
  1873 
  1874 
  1875 
  1876 New in Isabelle98-1 (October 1998)
  1877 ----------------------------------
  1878 
  1879 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1880 
  1881 * several changes of automated proof tools;
  1882 
  1883 * HOL: major changes to the inductive and datatype packages, including
  1884 some minor incompatibilities of theory syntax;
  1885 
  1886 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1887 called `inj_on';
  1888 
  1889 * HOL: removed duplicate thms in Arith:
  1890   less_imp_add_less  should be replaced by  trans_less_add1
  1891   le_imp_add_le      should be replaced by  trans_le_add1
  1892 
  1893 * HOL: unary minus is now overloaded (new type constraints may be
  1894 required);
  1895 
  1896 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1897 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1898 now taken as an integer constant.
  1899 
  1900 * Pure: ML function 'theory_of' renamed to 'theory';
  1901 
  1902 
  1903 *** Proof tools ***
  1904 
  1905 * Simplifier:
  1906   1. Asm_full_simp_tac is now more aggressive.
  1907      1. It will sometimes reorient premises if that increases their power to
  1908         simplify.
  1909      2. It does no longer proceed strictly from left to right but may also
  1910         rotate premises to achieve further simplification.
  1911      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1912      old Asm_full_simp_tac in that it does not rotate premises.
  1913   2. The simplifier now knows a little bit about nat-arithmetic.
  1914 
  1915 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1916 allows for selected deletion of wrappers, by introduction of names for
  1917 wrapper functionals.  This implies that addbefore, addSbefore,
  1918 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1919 and that adding two tactics with the same name overwrites the first
  1920 one (emitting a warning).
  1921   type wrapper = (int -> tactic) -> (int -> tactic)
  1922   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1923   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1924   delWrapper, delSWrapper: claset *  string            -> claset
  1925   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1926 
  1927 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1928 semantics; addbefore now affects only the unsafe part of step_tac
  1929 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1930 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1931 by Force_tac;
  1932 
  1933 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1934 compWrapper; added safe wrapper (and access functions for it);
  1935 
  1936 * HOL/split_all_tac is now much faster and fails if there is nothing
  1937 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1938 and the names of the automatically generated variables have changed.
  1939 split_all_tac has moved within claset() from unsafe wrappers to safe
  1940 wrappers, which means that !!-bound variables are split much more
  1941 aggressively, and safe_tac and clarify_tac now split such variables.
  1942 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1943 Note: the same holds for record_split_tac, which does the job of
  1944 split_all_tac for record fields.
  1945 
  1946 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1947 permanently to the default simpset using Addsplits just like
  1948 Addsimps. They can be removed via Delsplits just like
  1949 Delsimps. Lower-case versions are also available.
  1950 
  1951 * HOL/Simplifier: The rule split_if is now part of the default
  1952 simpset. This means that the simplifier will eliminate all occurrences
  1953 of if-then-else in the conclusion of a goal. To prevent this, you can
  1954 either remove split_if completely from the default simpset by
  1955 `Delsplits [split_if]' or remove it in a specific call of the
  1956 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1957 other case splitting rules to/from the default simpset: every datatype
  1958 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1959 t is the name of the datatype).
  1960 
  1961 * Classical reasoner / Simplifier combination: new force_tac (and
  1962 derivatives Force_tac, force) combines rewriting and classical
  1963 reasoning (and whatever other tools) similarly to auto_tac, but is
  1964 aimed to solve the given subgoal completely.
  1965 
  1966 
  1967 *** General ***
  1968 
  1969 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1970 and `goalw': the theory is no longer needed as an explicit argument -
  1971 the current theory context is used; assumptions are no longer returned
  1972 at the ML-level unless one of them starts with ==> or !!; it is
  1973 recommended to convert to these new commands using isatool fixgoal
  1974 (backup your sources first!);
  1975 
  1976 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1977 the current theory context, and 'theory' to lookup stored theories;
  1978 
  1979 * new theory section 'locale' for declaring constants, assumptions and
  1980 definitions that have local scope;
  1981 
  1982 * new theory section 'nonterminals' for purely syntactic types;
  1983 
  1984 * new theory section 'setup' for generic ML setup functions
  1985 (e.g. package initialization);
  1986 
  1987 * the distribution now includes Isabelle icons: see
  1988 lib/logo/isabelle-{small,tiny}.xpm;
  1989 
  1990 * isatool install - install binaries with absolute references to
  1991 ISABELLE_HOME/bin;
  1992 
  1993 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1994 
  1995 * print mode 'emacs' reserved for Isamode;
  1996 
  1997 * support multiple print (ast) translations per constant name;
  1998 
  1999 * theorems involving oracles are now printed with a suffixed [!];
  2000 
  2001 
  2002 *** HOL ***
  2003 
  2004 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2005 
  2006 * HOL/inductive package reorganized and improved: now supports mutual
  2007 definitions such as
  2008 
  2009   inductive EVEN ODD
  2010     intrs
  2011       null "0 : EVEN"
  2012       oddI "n : EVEN ==> Suc n : ODD"
  2013       evenI "n : ODD ==> Suc n : EVEN"
  2014 
  2015 new theorem list "elims" contains an elimination rule for each of the
  2016 recursive sets; inductive definitions now handle disjunctive premises
  2017 correctly (also ZF);
  2018 
  2019 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2020 "mutual_induct" no longer exists - the induction rule is always
  2021 contained in "induct";
  2022 
  2023 
  2024 * HOL/datatype package re-implemented and greatly improved: now
  2025 supports mutually recursive datatypes such as
  2026 
  2027   datatype
  2028     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2029             | SUM ('a aexp) ('a aexp)
  2030             | DIFF ('a aexp) ('a aexp)
  2031             | NUM 'a
  2032   and
  2033     'a bexp = LESS ('a aexp) ('a aexp)
  2034             | AND ('a bexp) ('a bexp)
  2035             | OR ('a bexp) ('a bexp)
  2036 
  2037 as well as indirectly recursive datatypes such as
  2038 
  2039   datatype
  2040     ('a, 'b) term = Var 'a
  2041                   | App 'b ((('a, 'b) term) list)
  2042 
  2043 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2044 induction on mutually / indirectly recursive datatypes.
  2045 
  2046 Primrec equations are now stored in theory and can be accessed via
  2047 <function_name>.simps.
  2048 
  2049 INCOMPATIBILITIES:
  2050 
  2051   - Theories using datatypes must now have theory Datatype as an
  2052     ancestor.
  2053   - The specific <typename>.induct_tac no longer exists - use the
  2054     generic induct_tac instead.
  2055   - natE has been renamed to nat.exhaust - use exhaust_tac
  2056     instead of res_inst_tac ... natE. Note that the variable
  2057     names in nat.exhaust differ from the names in natE, this
  2058     may cause some "fragile" proofs to fail.
  2059   - The theorems split_<typename>_case and split_<typename>_case_asm
  2060     have been renamed to <typename>.split and <typename>.split_asm.
  2061   - Since default sorts of type variables are now handled correctly,
  2062     some datatype definitions may have to be annotated with explicit
  2063     sort constraints.
  2064   - Primrec definitions no longer require function name and type
  2065     of recursive argument.
  2066 
  2067 Consider using isatool fixdatatype to adapt your theories and proof
  2068 scripts to the new package (backup your sources first!).
  2069 
  2070 
  2071 * HOL/record package: considerably improved implementation; now
  2072 includes concrete syntax for record types, terms, updates; theorems
  2073 for surjective pairing and splitting !!-bound record variables; proof
  2074 support is as follows:
  2075 
  2076   1) standard conversions (selectors or updates applied to record
  2077 constructor terms) are part of the standard simpset;
  2078 
  2079   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2080 made part of standard simpset and claset via addIffs;
  2081 
  2082   3) a tactic for record field splitting (record_split_tac) is part of
  2083 the standard claset (addSWrapper);
  2084 
  2085 To get a better idea about these rules you may retrieve them via
  2086 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2087 the name of your record type.
  2088 
  2089 The split tactic 3) conceptually simplifies by the following rule:
  2090 
  2091   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2092 
  2093 Thus any record variable that is bound by meta-all will automatically
  2094 blow up into some record constructor term, consequently the
  2095 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2096 solve record problems automatically.
  2097 
  2098 
  2099 * reorganized the main HOL image: HOL/Integ and String loaded by
  2100 default; theory Main includes everything;
  2101 
  2102 * automatic simplification of integer sums and comparisons, using cancellation;
  2103 
  2104 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2105 
  2106 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2107 
  2108 * many new identities for unions, intersections, set difference, etc.;
  2109 
  2110 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2111 called split_if, split_split, split_sum_case and split_nat_case (to go
  2112 with add/delsplits);
  2113 
  2114 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2115 (?x::unit) = (); this is made part of the default simpset, which COULD
  2116 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2117 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2118 unit_abs_eta_conv is added in order to counter the effect of
  2119 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2120 %u.f();
  2121 
  2122 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2123 makes more sense);
  2124 
  2125 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2126   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2127   disjointness reasoning but breaking a few old proofs.
  2128 
  2129 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2130 to 'converse' from 'inverse' (for compatibility with ZF and some
  2131 literature);
  2132 
  2133 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2134 the well-founded relation;
  2135 
  2136 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2137     Compl A.  The "Compl" syntax remains available as input syntax for this
  2138     release ONLY.
  2139 
  2140 * HOL/Update: new theory of function updates:
  2141     f(a:=b) == %x. if x=a then b else f x
  2142 may also be iterated as in f(a:=b,c:=d,...);
  2143 
  2144 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2145 
  2146 * HOL/List:
  2147   - new function list_update written xs[i:=v] that updates the i-th
  2148     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2149   - new function `upt' written [i..j(] which generates the list
  2150     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2151     bound write [i..j], which is a shorthand for [i..j+1(].
  2152   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2153 
  2154 * HOL/Arith:
  2155   - removed 'pred' (predecessor) function;
  2156   - generalized some theorems about n-1;
  2157   - many new laws about "div" and "mod";
  2158   - new laws about greatest common divisors (see theory ex/Primes);
  2159 
  2160 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2161 instead of "inverse";
  2162 
  2163 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2164   of the multiset ordering;
  2165 
  2166 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2167   (not included by default);
  2168 
  2169 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2170 
  2171 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2172   programs, i.e. different program variables may have different types.
  2173 
  2174 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2175   [previously, this check worked only if the rewrite rule was unconditional]
  2176   Now rew can involve either definitions or equalities (either == or =).
  2177 
  2178 
  2179 *** ZF ***
  2180 
  2181 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2182   only the theorems proved on ZF.ML;
  2183 
  2184 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2185   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2186   disjointness reasoning but breaking a few old proofs.
  2187 
  2188 * ZF/Update: new theory of function updates
  2189     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2190   may also be iterated as in f(a:=b,c:=d,...);
  2191 
  2192 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2193 
  2194 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2195   [previously, this check worked only if the rewrite rule was unconditional]
  2196   Now rew can involve either definitions or equalities (either == or =).
  2197 
  2198 * case_tac provided for compatibility with HOL
  2199     (like the old excluded_middle_tac, but with subgoals swapped)
  2200 
  2201 
  2202 *** Internal programming interfaces ***
  2203 
  2204 * Pure: several new basic modules made available for general use, see
  2205 also src/Pure/README;
  2206 
  2207 * improved the theory data mechanism to support encapsulation (data
  2208 kind name replaced by private Object.kind, acting as authorization
  2209 key); new type-safe user interface via functor TheoryDataFun; generic
  2210 print_data function becomes basically useless;
  2211 
  2212 * removed global_names compatibility flag -- all theory declarations
  2213 are qualified by default;
  2214 
  2215 * module Pure/Syntax now offers quote / antiquote translation
  2216 functions (useful for Hoare logic etc. with implicit dependencies);
  2217 see HOL/ex/Antiquote for an example use;
  2218 
  2219 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2220 cterm -> thm;
  2221 
  2222 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2223 subgoal;
  2224 
  2225 * Display.print_goals function moved to Locale.print_goals;
  2226 
  2227 * standard print function for goals supports current_goals_markers
  2228 variable for marking begin of proof, end of proof, start of goal; the
  2229 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2230 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2231 for example;
  2232 
  2233 
  2234 
  2235 New in Isabelle98 (January 1998)
  2236 --------------------------------
  2237 
  2238 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2239 
  2240 * changed lexical syntax of terms / types: dots made part of long
  2241 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2242 
  2243 * simpset (and claset) reference variable replaced by functions
  2244 simpset / simpset_ref;
  2245 
  2246 * no longer supports theory aliases (via merge) and non-trivial
  2247 implicit merge of thms' signatures;
  2248 
  2249 * most internal names of constants changed due to qualified names;
  2250 
  2251 * changed Pure/Sequence interface (see Pure/seq.ML);
  2252 
  2253 
  2254 *** General Changes ***
  2255 
  2256 * hierachically structured name spaces (for consts, types, axms, thms
  2257 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2258 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2259 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2260 long_names for fully qualified output names; NOTE: ML programs
  2261 (special tactics, packages etc.) referring to internal names may have
  2262 to be adapted to cope with fully qualified names; in case of severe
  2263 backward campatibility problems try setting 'global_names' at compile
  2264 time to have enrything declared within a flat name space; one may also
  2265 fine tune name declarations in theories via the 'global' and 'local'
  2266 section;
  2267 
  2268 * reimplemented the implicit simpset and claset using the new anytype
  2269 data filed in signatures; references simpset:simpset ref etc. are
  2270 replaced by functions simpset:unit->simpset and
  2271 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2272 to patch your ML files accordingly;
  2273 
  2274 * HTML output now includes theory graph data for display with Java
  2275 applet or isatool browser; data generated automatically via isatool
  2276 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2277 
  2278 * defs may now be conditional; improved rewrite_goals_tac to handle
  2279 conditional equations;
  2280 
  2281 * defs now admits additional type arguments, using TYPE('a) syntax;
  2282 
  2283 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2284 creates a new theory node; implicit merge of thms' signatures is
  2285 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2286 transfer:theory->thm->thm in (rare) cases;
  2287 
  2288 * improved handling of draft signatures / theories; draft thms (and
  2289 ctyps, cterms) are automatically promoted to real ones;
  2290 
  2291 * slightly changed interfaces for oracles: admit many per theory, named
  2292 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2293 
  2294 * print_goals: optional output of const types (set show_consts and
  2295 show_types);
  2296 
  2297 * improved output of warnings (###) and errors (***);
  2298 
  2299 * subgoal_tac displays a warning if the new subgoal has type variables;
  2300 
  2301 * removed old README and Makefiles;
  2302 
  2303 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2304 
  2305 * removed obsolete init_pps and init_database;
  2306 
  2307 * deleted the obsolete tactical STATE, which was declared by
  2308     fun STATE tacfun st = tacfun st st;
  2309 
  2310 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2311 (which abbreviates $HOME);
  2312 
  2313 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2314 use isatool fixseq to adapt your ML programs (this works for fully
  2315 qualified references to the Sequence structure only!);
  2316 
  2317 * use_thy no longer requires writable current directory; it always
  2318 reloads .ML *and* .thy file, if either one is out of date;
  2319 
  2320 
  2321 *** Classical Reasoner ***
  2322 
  2323 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2324 tactics that use classical reasoning to simplify a subgoal without
  2325 splitting it into several subgoals;
  2326 
  2327 * Safe_tac: like safe_tac but uses the default claset;
  2328 
  2329 
  2330 *** Simplifier ***
  2331 
  2332 * added simplification meta rules:
  2333     (asm_)(full_)simplify: simpset -> thm -> thm;
  2334 
  2335 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2336 logics (again);
  2337 
  2338 * added prems argument to simplification procedures;
  2339 
  2340 * HOL, FOL, ZF: added infix function `addsplits':
  2341   instead of `<simpset> setloop (split_tac <thms>)'
  2342   you can simply write `<simpset> addsplits <thms>'
  2343 
  2344 
  2345 *** Syntax ***
  2346 
  2347 * TYPE('a) syntax for type reflection terms;
  2348 
  2349 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2350 
  2351 * pretty printer: changed order of mixfix annotation preference (again!);
  2352 
  2353 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2354 
  2355 
  2356 *** HOL ***
  2357 
  2358 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2359   with `addloop' of the simplifier to faciliate case splitting in premises.
  2360 
  2361 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2362 
  2363 * HOL/Auth: new protocol proofs including some for the Internet
  2364   protocol TLS;
  2365 
  2366 * HOL/Map: new theory of `maps' a la VDM;
  2367 
  2368 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2369 cancelling out common nat summands from =, <, <= (in)equalities, or
  2370 differences; simplification procedures nat_cancel_factor for
  2371 cancelling common factor from =, <, <= (in)equalities over natural
  2372 sums; nat_cancel contains both kinds of procedures, it is installed by
  2373 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2374 
  2375 * HOL/simplifier: terms of the form
  2376   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2377   are rewritten to
  2378   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2379   and those of the form
  2380   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2381   are rewritten to
  2382   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2383 
  2384 * HOL/datatype
  2385   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2386 
  2387   P(t_case f1 ... fn x) =
  2388      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2389         ...
  2390        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2391      )
  2392 
  2393   and a theorem `split_t_case_asm' of the form
  2394 
  2395   P(t_case f1 ... fn x) =
  2396     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2397         ...
  2398        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2399      )
  2400   which can be added to a simpset via `addsplits'. The existing theorems
  2401   expand_list_case and expand_option_case have been renamed to
  2402   split_list_case and split_option_case.
  2403 
  2404 * HOL/Arithmetic:
  2405   - `pred n' is automatically converted to `n-1'.
  2406     Users are strongly encouraged not to use `pred' any longer,
  2407     because it will disappear altogether at some point.
  2408   - Users are strongly encouraged to write "0 < n" rather than
  2409     "n ~= 0". Theorems and proof tools have been modified towards this
  2410     `standard'.
  2411 
  2412 * HOL/Lists:
  2413   the function "set_of_list" has been renamed "set" (and its theorems too);
  2414   the function "nth" now takes its arguments in the reverse order and
  2415   has acquired the infix notation "!" as in "xs!n".
  2416 
  2417 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2418 
  2419 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2420   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2421 
  2422 * HOL/record: extensible records with schematic structural subtyping
  2423 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2424 still lacks various theorems and concrete record syntax;
  2425 
  2426 
  2427 *** HOLCF ***
  2428 
  2429 * removed "axioms" and "generated by" sections;
  2430 
  2431 * replaced "ops" section by extended "consts" section, which is capable of
  2432   handling the continuous function space "->" directly;
  2433 
  2434 * domain package:
  2435   . proves theorems immediately and stores them in the theory,
  2436   . creates hierachical name space,
  2437   . now uses normal mixfix annotations (instead of cinfix...),
  2438   . minor changes to some names and values (for consistency),
  2439   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2440   . separator between mutual domain defs: changed "," to "and",
  2441   . improved handling of sort constraints;  now they have to
  2442     appear on the left-hand side of the equations only;
  2443 
  2444 * fixed LAM <x,y,zs>.b syntax;
  2445 
  2446 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2447 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2448 
  2449 
  2450 *** FOL and ZF ***
  2451 
  2452 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2453   with `addloop' of the simplifier to faciliate case splitting in premises.
  2454 
  2455 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2456 in HOL, they strip ALL and --> from proved theorems;
  2457 
  2458 
  2459 
  2460 New in Isabelle94-8 (May 1997)
  2461 ------------------------------
  2462 
  2463 *** General Changes ***
  2464 
  2465 * new utilities to build / run / maintain Isabelle etc. (in parts
  2466 still somewhat experimental); old Makefiles etc. still functional;
  2467 
  2468 * new 'Isabelle System Manual';
  2469 
  2470 * INSTALL text, together with ./configure and ./build scripts;
  2471 
  2472 * reimplemented type inference for greater efficiency, better error
  2473 messages and clean internal interface;
  2474 
  2475 * prlim command for dealing with lots of subgoals (an easier way of
  2476 setting goals_limit);
  2477 
  2478 
  2479 *** Syntax ***
  2480 
  2481 * supports alternative (named) syntax tables (parser and pretty
  2482 printer); internal interface is provided by add_modesyntax(_i);
  2483 
  2484 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2485 be used in conjunction with the Isabelle symbol font; uses the
  2486 "symbols" syntax table;
  2487 
  2488 * added token_translation interface (may translate name tokens in
  2489 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2490 the current print_mode); IMPORTANT: user print translation functions
  2491 are responsible for marking newly introduced bounds
  2492 (Syntax.mark_boundT);
  2493 
  2494 * token translations for modes "xterm" and "xterm_color" that display
  2495 names in bold, underline etc. or colors (which requires a color
  2496 version of xterm);
  2497 
  2498 * infixes may now be declared with names independent of their syntax;
  2499 
  2500 * added typed_print_translation (like print_translation, but may
  2501 access type of constant);
  2502 
  2503 
  2504 *** Classical Reasoner ***
  2505 
  2506 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2507 some limitations.  Blast_tac...
  2508   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2509   + ignores elimination rules that don't have the correct format
  2510         (the conclusion MUST be a formula variable)
  2511   + ignores types, which can make HOL proofs fail
  2512   + rules must not require higher-order unification, e.g. apply_type in ZF
  2513     [message "Function Var's argument not a bound variable" relates to this]
  2514   + its proof strategy is more general but can actually be slower
  2515 
  2516 * substitution with equality assumptions no longer permutes other
  2517 assumptions;
  2518 
  2519 * minor changes in semantics of addafter (now called addaltern); renamed
  2520 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2521 (and access functions for it);
  2522 
  2523 * improved combination of classical reasoner and simplifier:
  2524   + functions for handling clasimpsets
  2525   + improvement of addss: now the simplifier is called _after_ the
  2526     safe steps.
  2527   + safe variant of addss called addSss: uses safe simplifications
  2528     _during_ the safe steps. It is more complete as it allows multiple
  2529     instantiations of unknowns (e.g. with slow_tac).
  2530 
  2531 *** Simplifier ***
  2532 
  2533 * added interface for simplification procedures (functions that
  2534 produce *proven* rewrite rules on the fly, depending on current
  2535 redex);
  2536 
  2537 * ordering on terms as parameter (used for ordered rewriting);
  2538 
  2539 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2540 
  2541 * the solver is now split into a safe and an unsafe part.
  2542 This should be invisible for the normal user, except that the
  2543 functions setsolver and addsolver have been renamed to setSolver and
  2544 addSolver; added safe_asm_full_simp_tac;
  2545 
  2546 
  2547 *** HOL ***
  2548 
  2549 * a generic induction tactic `induct_tac' which works for all datatypes and
  2550 also for type `nat';
  2551 
  2552 * a generic case distinction tactic `exhaust_tac' which works for all
  2553 datatypes and also for type `nat';
  2554 
  2555 * each datatype comes with a function `size';
  2556 
  2557 * patterns in case expressions allow tuple patterns as arguments to
  2558 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2559 
  2560 * primrec now also works with type nat;
  2561 
  2562 * recdef: a new declaration form, allows general recursive functions to be
  2563 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2564 
  2565 * the constant for negation has been renamed from "not" to "Not" to
  2566 harmonize with FOL, ZF, LK, etc.;
  2567 
  2568 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2569 infinite lists;
  2570 
  2571 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2572 
  2573 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2574 problems in commutative rings, using axiomatic type classes for + and *;
  2575 
  2576 * more examples in HOL/MiniML and HOL/Auth;
  2577 
  2578 * more default rewrite rules for quantifiers, union/intersection;
  2579 
  2580 * a new constant `arbitrary == @x.False';
  2581 
  2582 * HOLCF/IOA replaces old HOL/IOA;
  2583 
  2584 * HOLCF changes: derived all rules and arities
  2585   + axiomatic type classes instead of classes
  2586   + typedef instead of faking type definitions
  2587   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2588   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2589   + eliminated the types void, one, tr
  2590   + use unit lift and bool lift (with translations) instead of one and tr
  2591   + eliminated blift from Lift3.thy (use Def instead of blift)
  2592   all eliminated rules are derived as theorems --> no visible changes ;
  2593 
  2594 
  2595 *** ZF ***
  2596 
  2597 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2598 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2599 as ZF_cs addSIs [equalityI];
  2600 
  2601 
  2602 
  2603 New in Isabelle94-7 (November 96)
  2604 ---------------------------------
  2605 
  2606 * allowing negative levels (as offsets) in prlev and choplev;
  2607 
  2608 * super-linear speedup for large simplifications;
  2609 
  2610 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2611 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2612 FAIL); can suppress it using the command Delsimps (ex_simps @
  2613 all_simps); De Morgan laws are also now included, by default;
  2614 
  2615 * improved printing of ==>  :  ~:
  2616 
  2617 * new object-logic "Sequents" adds linear logic, while replacing LK
  2618 and Modal (thanks to Sara Kalvala);
  2619 
  2620 * HOL/Auth: correctness proofs for authentication protocols;
  2621 
  2622 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2623 examples on HOL/Auth);
  2624 
  2625 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2626 the rewriter and classical reasoner simultaneously;
  2627 
  2628 * function uresult no longer returns theorems in "standard" format;
  2629 regain previous version by: val uresult = standard o uresult;
  2630 
  2631 
  2632 
  2633 New in Isabelle94-6
  2634 -------------------
  2635 
  2636 * oracles -- these establish an interface between Isabelle and trusted
  2637 external reasoners, which may deliver results as theorems;
  2638 
  2639 * proof objects (in particular record all uses of oracles);
  2640 
  2641 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2642 
  2643 * "constdefs" section in theory files;
  2644 
  2645 * "primrec" section (HOL) no longer requires names;
  2646 
  2647 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2648 
  2649 
  2650 
  2651 New in Isabelle94-5
  2652 -------------------
  2653 
  2654 * reduced space requirements;
  2655 
  2656 * automatic HTML generation from theories;
  2657 
  2658 * theory files no longer require "..." (quotes) around most types;
  2659 
  2660 * new examples, including two proofs of the Church-Rosser theorem;
  2661 
  2662 * non-curried (1994) version of HOL is no longer distributed;
  2663 
  2664 
  2665 
  2666 New in Isabelle94-4
  2667 -------------------
  2668 
  2669 * greatly reduced space requirements;
  2670 
  2671 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2672 
  2673 * searchable theorem database (see the section "Retrieving theorems" on
  2674 page 8 of the Reference Manual);
  2675 
  2676 * new examples, including Grabczewski's monumental case study of the
  2677 Axiom of Choice;
  2678 
  2679 * The previous version of HOL renamed to Old_HOL;
  2680 
  2681 * The new version of HOL (previously called CHOL) uses a curried syntax
  2682 for functions.  Application looks like f a b instead of f(a,b);
  2683 
  2684 * Mutually recursive inductive definitions finally work in HOL;
  2685 
  2686 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2687 translates to the operator "split";
  2688 
  2689 
  2690 
  2691 New in Isabelle94-3
  2692 -------------------
  2693 
  2694 * new infix operator, addss, allowing the classical reasoner to
  2695 perform simplification at each step of its search.  Example:
  2696         fast_tac (cs addss ss)
  2697 
  2698 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2699 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2700 look like (a,b) instead of <a,b>;
  2701 
  2702 * PLEASE NOTE: CHOL will eventually replace HOL!
  2703 
  2704 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2705 It translates to the operator "split".  A new theory of integers is available;
  2706 
  2707 * In ZF, integer numerals now denote two's-complement binary integers.
  2708 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2709 
  2710 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2711 of the Axiom of Choice;
  2712 
  2713 
  2714 
  2715 New in Isabelle94-2
  2716 -------------------
  2717 
  2718 * Significantly faster resolution;
  2719 
  2720 * the different sections in a .thy file can now be mixed and repeated
  2721 freely;
  2722 
  2723 * Database of theorems for FOL, HOL and ZF.  New
  2724 commands including qed, qed_goal and bind_thm store theorems in the database.
  2725 
  2726 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2727 a given theory (thms_of), or find out what theory a theorem was proved in
  2728 (theory_of_thm);
  2729 
  2730 * Bugs fixed in the inductive definition and datatype packages;
  2731 
  2732 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2733 and HOL_dup_cs obsolete;
  2734 
  2735 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2736 have been removed;
  2737 
  2738 * Simpler definition of function space in ZF;
  2739 
  2740 * new results about cardinal and ordinal arithmetic in ZF;
  2741 
  2742 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2743 types;
  2744 
  2745 
  2746 $Id$