NEWS
author schirmer
Wed Jun 30 14:04:58 2004 +0200 (2004-06-30)
changeset 15012 28fa57b57209
parent 15011 35be762f58f9
child 15018 0a84ca4e0f90
permissions -rw-r--r--
Added reference record_definition_quick_and_dirty_sensitive, to
skip proofs triggered by a record definition, if quick_and_dirty
is enabled.
     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/record: Reference record_definition_quick_and_dirty_sensitive
   100   can be enabled to skip the proofs triggered by a record definition
   101   (if quick_and_dirty is enabled). Definitions of large records can
   102   take quite long.
   103 
   104 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
   105 
   106   syntax (epsilon)
   107     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   108 
   109   The symbol \<some> is displayed as the alternative epsilon of LaTeX
   110   and x-symbol; use option '-m epsilon' to get it actually printed.
   111   Moreover, the mathematically important symbolic identifier
   112   \<epsilon> becomes available as variable, constant etc.
   113 
   114 * Simplifier: "record_upd_simproc" for simplification of multiple
   115   record updates enabled by default.  INCOMPATIBILITY: old proofs
   116   break occasionally, since simplification is more powerful by
   117   default.
   118 
   119 
   120 *** HOLCF ***
   121 
   122 * HOLCF: discontinued special version of 'constdefs' (which used to
   123   support continuous functions) in favor of the general Pure one with
   124   full type-inference.
   125 
   126 
   127 *** ZF ***
   128 
   129 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the First
   130   Isomorphism Theorem (on quotienting by the kernel of a homomorphism).
   131 
   132 
   133 
   134 New in Isabelle2004 (April 2004)
   135 --------------------------------
   136 
   137 *** General ***
   138 
   139 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   140   Replaces linorder.ML.
   141 
   142 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   143   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   144   (\<a>...\<z>), are now considered normal letters, and can therefore
   145   be used anywhere where an ASCII letter (a...zA...Z) has until
   146   now. COMPATIBILITY: This obviously changes the parsing of some
   147   terms, especially where a symbol has been used as a binder, say
   148   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   149   as an identifier.  Fix it by inserting a space around former
   150   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   151   existing theory and ML files.
   152 
   153 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   154 
   155 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   156   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   157   a normal (but invisible) letter. For multiple letter subscripts repeat
   158   \<^isub> like this: x\<^isub>1\<^isub>2.
   159 
   160 * Pure: There are now sub-/superscripts that can span more than one
   161   character. Text between \<^bsub> and \<^esub> is set in subscript in
   162   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   163   superscript. The new control characters are not identifier parts.
   164 
   165 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   166   content of "..." to the latex file instead of \isacntrl... . The "..."
   167   may consist of any printable characters excluding the end bracket >.
   168 
   169 * Pure: Using new Isar command "finalconsts" (or the ML functions
   170   Theory.add_finals or Theory.add_finals_i) it is now possible to
   171   declare constants "final", which prevents their being given a definition
   172   later.  It is useful for constants whose behaviour is fixed axiomatically
   173   rather than definitionally, such as the meta-logic connectives.
   174 
   175 * Pure: 'instance' now handles general arities with general sorts
   176   (i.e. intersections of classes),
   177 
   178 * Presentation: generated HTML now uses a CSS style sheet to make layout
   179   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   180   It can be changed to alter the colors/layout of generated pages.
   181 
   182 
   183 *** Isar ***
   184 
   185 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   186   cut_tac, subgoal_tac and thin_tac:
   187   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   188     locales are no longer forced to write Isar proof scripts.
   189     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   190     emulations.
   191   - INCOMPATIBILITY: names of variables to be instantiated may no
   192     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   193     This is consistent with the instantiation attribute "where".
   194 
   195 * Attributes "where" and "of":
   196   - Now take type variables of instantiated theorem into account when reading
   197     the instantiation string.  This fixes a bug that caused instantiated
   198     theorems to have too special types in some circumstances.
   199   - "where" permits explicit instantiations of type variables.
   200 
   201 * Calculation commands "moreover" and "also" no longer interfere with
   202   current facts ("this"), admitting arbitrary combinations with "then"
   203   and derived forms.
   204 
   205 * Locales:
   206   - Goal statements involving the context element "includes" no longer
   207     generate theorems with internal delta predicates (those ending on
   208     "_axioms") in the premise.
   209     Resolve particular premise with <locale>.intro to obtain old form.
   210   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   211     specification and "includes" elements in goal statement.
   212   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   213     [intro?] and [elim?] (respectively) by default.
   214   - Experimental command for instantiation of locales in proof contexts:
   215         instantiate <label>[<attrs>]: <loc>
   216     Instantiates locale <loc> and adds all its theorems to the current context
   217     taking into account their attributes.  Label and attrs are optional
   218     modifiers, like in theorem declarations.  If present, names of
   219     instantiated theorems are qualified with <label>, and the attributes
   220     <attrs> are applied after any attributes these theorems might have already.
   221       If the locale has assumptions, a chained fact of the form
   222     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   223     are derived.  The command does not support old-style locales declared
   224     with "locale (open)".
   225       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   226 
   227 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   228   (Isar) contexts.
   229 
   230 
   231 *** HOL ***
   232 
   233 * Proof import: new image HOL4 contains the imported library from
   234   the HOL4 system with about 2500 theorems. It is imported by
   235   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   236   can be used like any other Isabelle image.  See
   237   HOL/Import/HOL/README for more information.
   238 
   239 * Simplifier:
   240   - Much improved handling of linear and partial orders.
   241     Reasoners for linear and partial orders are set up for type classes
   242     "linorder" and "order" respectively, and are added to the default simpset
   243     as solvers.  This means that the simplifier can build transitivity chains
   244     to solve goals from the assumptions.
   245   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   246     of blast or auto after simplification become unnecessary because the goal
   247     is solved by simplification already.
   248 
   249 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   250     all proved in axiomatic type classes for semirings, rings and fields.
   251 
   252 * Numerics:
   253   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   254     now formalized using the Ring_and_Field theory mentioned above.
   255   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   256     than before, because now they are set up once in a generic manner.
   257   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   258     Look for the general versions in Ring_and_Field (and Power if they concern
   259     exponentiation).
   260 
   261 * Type "rat" of the rational numbers is now available in HOL-Complex.
   262 
   263 * Records:
   264   - Record types are now by default printed with their type abbreviation
   265     instead of the list of all field types. This can be configured via
   266     the reference "print_record_type_abbr".
   267   - Simproc "record_upd_simproc" for simplification of multiple updates added
   268     (not enabled by default).
   269   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   270     EX x. x = sel r to True (not enabled by default).
   271   - Tactic "record_split_simp_tac" to split and simplify records added.
   272 
   273 * 'specification' command added, allowing for definition by
   274   specification.  There is also an 'ax_specification' command that
   275   introduces the new constants axiomatically.
   276 
   277 * arith(_tac) is now able to generate counterexamples for reals as well.
   278 
   279 * HOL-Algebra: new locale "ring" for non-commutative rings.
   280 
   281 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   282   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   283 
   284 * HOL-Matrix: a first theory for matrices in HOL with an application of
   285   matrix theory to linear programming.
   286 
   287 * Unions and Intersections:
   288   The x-symbol output syntax of UN and INT has been changed
   289   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   290   i.e. the index formulae has become a subscript, like in normal math.
   291   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   292   The subscript version is also accepted as input syntax.
   293 
   294 * Unions and Intersections over Intervals:
   295   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   296   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   297   like in normal math, and corresponding versions for < and for intersection.
   298 
   299 * ML: the legacy theory structures Int and List have been removed. They had
   300   conflicted with ML Basis Library structures having the same names.
   301 
   302 * 'refute' command added to search for (finite) countermodels.  Only works
   303   for a fragment of HOL.  The installation of an external SAT solver is
   304   highly recommended.  See "HOL/Refute.thy" for details.
   305 
   306 * 'quickcheck' command: Allows to find counterexamples by evaluating
   307   formulae under an assignment of free variables to random values.
   308   In contrast to 'refute', it can deal with inductive datatypes,
   309   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   310   for examples.
   311 
   312 
   313 *** HOLCF ***
   314 
   315 * Streams now come with concatenation and are part of the HOLCF image
   316 
   317 
   318 
   319 New in Isabelle2003 (May 2003)
   320 ------------------------------
   321 
   322 *** General ***
   323 
   324 * Provers/simplifier:
   325 
   326   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   327     Assumptions are now subject to complete mutual simplification,
   328     not just from left to right. The simplifier now preserves
   329     the order of assumptions.
   330 
   331     Potential INCOMPATIBILITY:
   332 
   333     -- simp sometimes diverges where the old version did
   334        not, e.g. invoking simp on the goal
   335 
   336         [| P (f x); y = x; f x = f y |] ==> Q
   337 
   338        now gives rise to the infinite reduction sequence
   339 
   340         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   341 
   342        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   343        kind of problem.
   344 
   345     -- Tactics combining classical reasoner and simplification (such as auto)
   346        are also affected by this change, because many of them rely on
   347        simp. They may sometimes diverge as well or yield a different numbers
   348        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   349        in case of problems. Sometimes subsequent calls to the classical
   350        reasoner will fail because a preceeding call to the simplifier too
   351        eagerly simplified the goal, e.g. deleted redundant premises.
   352 
   353   - The simplifier trace now shows the names of the applied rewrite rules
   354 
   355   - You can limit the number of recursive invocations of the simplifier
   356     during conditional rewriting (where the simplifie tries to solve the
   357     conditions before applying the rewrite rule):
   358     ML "simp_depth_limit := n"
   359     where n is an integer. Thus you can force termination where previously
   360     the simplifier would diverge.
   361 
   362   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   363 
   364   - No longer aborts on failed congruence proof.  Instead, the
   365     congruence is ignored.
   366 
   367 * Pure: New generic framework for extracting programs from constructive
   368   proofs. See HOL/Extraction.thy for an example instantiation, as well
   369   as HOL/Extraction for some case studies.
   370 
   371 * Pure: The main goal of the proof state is no longer shown by default, only
   372 the subgoals. This behaviour is controlled by a new flag.
   373    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   374 (ML: Proof.show_main_goal).
   375 
   376 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   377 rules whose conclusion matches subgoal 1:
   378       PG menu: Isabelle/Isar -> Show me -> matching rules
   379 The rules are ordered by how closely they match the subgoal.
   380 In particular, rules that solve a subgoal outright are displayed first
   381 (or rather last, the way they are printed).
   382 (ML: ProofGeneral.print_intros())
   383 
   384 * Pure: New flag trace_unify_fail causes unification to print
   385 diagnostic information (PG: in trace buffer) when it fails. This is
   386 useful for figuring out why single step proofs like rule, erule or
   387 assumption failed.
   388 
   389 * Pure: Locale specifications now produce predicate definitions
   390 according to the body of text (covering assumptions modulo local
   391 definitions); predicate "loc_axioms" covers newly introduced text,
   392 while "loc" is cumulative wrt. all included locale expressions; the
   393 latter view is presented only on export into the global theory
   394 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   395 on the old view without predicates;
   396 
   397 * Pure: predefined locales "var" and "struct" are useful for sharing
   398 parameters (as in CASL, for example); just specify something like
   399 ``var x + var y + struct M'' as import;
   400 
   401 * Pure: improved thms_containing: proper indexing of facts instead of
   402 raw theorems; check validity of results wrt. current name space;
   403 include local facts of proof configuration (also covers active
   404 locales), cover fixed variables in index; may use "_" in term
   405 specification; an optional limit for the number of printed facts may
   406 be given (the default is 40);
   407 
   408 * Pure: disallow duplicate fact bindings within new-style theory files
   409 (batch-mode only);
   410 
   411 * Provers: improved induct method: assumptions introduced by case
   412 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   413 the goal statement); "foo" still refers to all facts collectively;
   414 
   415 * Provers: the function blast.overloaded has been removed: all constants
   416 are regarded as potentially overloaded, which improves robustness in exchange
   417 for slight decrease in efficiency;
   418 
   419 * Provers/linorder: New generic prover for transitivity reasoning over
   420 linear orders.  Note: this prover is not efficient!
   421 
   422 * Isar: preview of problems to finish 'show' now produce an error
   423 rather than just a warning (in interactive mode);
   424 
   425 
   426 *** HOL ***
   427 
   428 * arith(_tac)
   429 
   430  - Produces a counter example if it cannot prove a goal.
   431    Note that the counter example may be spurious if the goal is not a formula
   432    of quantifier-free linear arithmetic.
   433    In ProofGeneral the counter example appears in the trace buffer.
   434 
   435  - Knows about div k and mod k where k is a numeral of type nat or int.
   436 
   437  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   438    linear arithmetic fails. This takes account of quantifiers and divisibility.
   439    Presburger arithmetic can also be called explicitly via presburger(_tac).
   440 
   441 * simp's arithmetic capabilities have been enhanced a bit: it now
   442 takes ~= in premises into account (by performing a case split);
   443 
   444 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   445 are distributed over a sum of terms;
   446 
   447 * New tactic "trans_tac" and method "trans" instantiate
   448 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   449 "<=", "<" and "=").
   450 
   451 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   452 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   453 
   454 * 'typedef' command has new option "open" to suppress the set
   455 definition;
   456 
   457 * functions Min and Max on finite sets have been introduced (theory
   458 Finite_Set);
   459 
   460 * attribute [symmetric] now works for relations as well; it turns
   461 (x,y) : R^-1 into (y,x) : R, and vice versa;
   462 
   463 * induct over a !!-quantified statement (say !!x1..xn):
   464   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   465 
   466 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   467 %x. None. Warning: empty_def now refers to the previously hidden definition
   468 of the empty set.
   469 
   470 * Algebra: formalization of classical algebra.  Intended as base for
   471 any algebraic development in Isabelle.  Currently covers group theory
   472 (up to Sylow's theorem) and ring theory (Universal Property of
   473 Univariate Polynomials).  Contributions welcome;
   474 
   475 * GroupTheory: deleted, since its material has been moved to Algebra;
   476 
   477 * Complex: new directory of the complex numbers with numeric constants,
   478 nonstandard complex numbers, and some complex analysis, standard and
   479 nonstandard (Jacques Fleuriot);
   480 
   481 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   482 
   483 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   484 Fleuriot);
   485 
   486 * Real/HahnBanach: updated and adapted to locales;
   487 
   488 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   489 Gray and Kramer);
   490 
   491 * UNITY: added the Meier-Sanders theory of progress sets;
   492 
   493 * MicroJava: bytecode verifier and lightweight bytecode verifier
   494 as abstract algorithms, instantiated to the JVM;
   495 
   496 * Bali: Java source language formalization. Type system, operational
   497 semantics, axiomatic semantics. Supported language features:
   498 classes, interfaces, objects,virtual methods, static methods,
   499 static/instance fields, arrays, access modifiers, definite
   500 assignment, exceptions.
   501 
   502 
   503 *** ZF ***
   504 
   505 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   506 universe, etc.);
   507 
   508 * Main ZF: virtually all theories converted to new-style format;
   509 
   510 
   511 *** ML ***
   512 
   513 * Pure: Tactic.prove provides sane interface for internal proofs;
   514 omits the infamous "standard" operation, so this is more appropriate
   515 than prove_goalw_cterm in many situations (e.g. in simprocs);
   516 
   517 * Pure: improved error reporting of simprocs;
   518 
   519 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   520 up simprocs;
   521 
   522 
   523 *** Document preparation ***
   524 
   525 * uses \par instead of \\ for line breaks in theory text. This may
   526 shift some page breaks in large documents. To get the old behaviour
   527 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   528 
   529 * minimized dependencies of isabelle.sty and isabellesym.sty on
   530 other packages
   531 
   532 * \<euro> now needs package babel/greek instead of marvosym (which
   533 broke \Rightarrow)
   534 
   535 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   536 textcomp package)
   537 
   538 
   539 
   540 New in Isabelle2002 (March 2002)
   541 --------------------------------
   542 
   543 *** Document preparation ***
   544 
   545 * greatly simplified document preparation setup, including more
   546 graceful interpretation of isatool usedir -i/-d/-D options, and more
   547 instructive isatool mkdir; users should basically be able to get
   548 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   549 users may run a separate document processing stage manually like this:
   550 "isatool usedir -D output HOL Test && isatool document Test/output";
   551 
   552 * theory dependency graph may now be incorporated into documents;
   553 isatool usedir -g true will produce session_graph.eps/.pdf for use
   554 with \includegraphics of LaTeX;
   555 
   556 * proper spacing of consecutive markup elements, especially text
   557 blocks after section headings;
   558 
   559 * support bold style (for single symbols only), input syntax is like
   560 this: "\<^bold>\<alpha>" or "\<^bold>A";
   561 
   562 * \<bullet> is now output as bold \cdot by default, which looks much
   563 better in printed text;
   564 
   565 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   566 note that these symbols are currently unavailable in Proof General /
   567 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   568 
   569 * isatool latex no longer depends on changed TEXINPUTS, instead
   570 isatool document copies the Isabelle style files to the target
   571 location;
   572 
   573 
   574 *** Isar ***
   575 
   576 * Pure/Provers: improved proof by cases and induction;
   577   - 'case' command admits impromptu naming of parameters (such as
   578     "case (Suc n)");
   579   - 'induct' method divinates rule instantiation from the inductive
   580     claim; no longer requires excessive ?P bindings for proper
   581     instantiation of cases;
   582   - 'induct' method properly enumerates all possibilities of set/type
   583     rules; as a consequence facts may be also passed through *type*
   584     rules without further ado;
   585   - 'induct' method now derives symbolic cases from the *rulified*
   586     rule (before it used to rulify cases stemming from the internal
   587     atomized version); this means that the context of a non-atomic
   588     statement becomes is included in the hypothesis, avoiding the
   589     slightly cumbersome show "PROP ?case" form;
   590   - 'induct' may now use elim-style induction rules without chaining
   591     facts, using ``missing'' premises from the goal state; this allows
   592     rules stemming from inductive sets to be applied in unstructured
   593     scripts, while still benefitting from proper handling of non-atomic
   594     statements; NB: major inductive premises need to be put first, all
   595     the rest of the goal is passed through the induction;
   596   - 'induct' proper support for mutual induction involving non-atomic
   597     rule statements (uses the new concept of simultaneous goals, see
   598     below);
   599   - append all possible rule selections, but only use the first
   600     success (no backtracking);
   601   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   602   - undeclared rule case names default to numbers 1, 2, 3, ...;
   603   - added 'print_induct_rules' (covered by help item in recent Proof
   604     General versions);
   605   - moved induct/cases attributes to Pure, methods to Provers;
   606   - generic method setup instantiated for FOL and HOL;
   607 
   608 * Pure: support multiple simultaneous goal statements, for example
   609 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   610 meta-level mechanism, this acts as if several individual goals had
   611 been stated separately; in particular common proof methods need to be
   612 repeated in order to cover all claims; note that a single elimination
   613 step is *not* sufficient to establish the two conjunctions, so this
   614 fails:
   615 
   616   assume "A & B" then have A and B ..   (*".." fails*)
   617 
   618 better use "obtain" in situations as above; alternative refer to
   619 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   620 
   621 * Pure: proper integration with ``locales''; unlike the original
   622 version by Florian Kammüller, Isar locales package high-level proof
   623 contexts rather than raw logical ones (e.g. we admit to include
   624 attributes everywhere); operations on locales include merge and
   625 rename; support for implicit arguments (``structures''); simultaneous
   626 type-inference over imports and text; see also HOL/ex/Locales.thy for
   627 some examples;
   628 
   629 * Pure: the following commands have been ``localized'', supporting a
   630 target locale specification "(in name)": 'lemma', 'theorem',
   631 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   632 stored both within the locale and at the theory level (exported and
   633 qualified by the locale name);
   634 
   635 * Pure: theory goals may now be specified in ``long'' form, with
   636 ad-hoc contexts consisting of arbitrary locale elements. for example
   637 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   638 definitions may be given, too); the result is a meta-level rule with
   639 the context elements being discharged in the obvious way;
   640 
   641 * Pure: new proof command 'using' allows to augment currently used
   642 facts after a goal statement ('using' is syntactically analogous to
   643 'apply', but acts on the goal's facts only); this allows chained facts
   644 to be separated into parts given before and after a claim, as in
   645 ``from a and b have C using d and e <proof>'';
   646 
   647 * Pure: renamed "antecedent" case to "rule_context";
   648 
   649 * Pure: new 'judgment' command records explicit information about the
   650 object-logic embedding (used by several tools internally); no longer
   651 use hard-wired "Trueprop";
   652 
   653 * Pure: added 'corollary' command;
   654 
   655 * Pure: fixed 'token_translation' command;
   656 
   657 * Pure: removed obsolete 'exported' attribute;
   658 
   659 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   660 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   661 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   662 
   663 * Pure: method 'atomize' presents local goal premises as object-level
   664 statements (atomic meta-level propositions); setup controlled via
   665 rewrite rules declarations of 'atomize' attribute; example
   666 application: 'induct' method with proper rule statements in improper
   667 proof *scripts*;
   668 
   669 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   670 now consider the syntactic context of assumptions, giving a better
   671 chance to get type-inference of the arguments right (this is
   672 especially important for locales);
   673 
   674 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   675 mode;
   676 
   677 * Pure/obtain: the formal conclusion "thesis", being marked as
   678 ``internal'', may no longer be reference directly in the text;
   679 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   680 situations;
   681 
   682 * Pure: generic 'sym' attribute which declares a rule both as pure
   683 'elim?' and for the 'symmetric' operation;
   684 
   685 * Pure: marginal comments ``--'' may now occur just anywhere in the
   686 text; the fixed correlation with particular command syntax has been
   687 discontinued;
   688 
   689 * Pure: new method 'rules' is particularly well-suited for proof
   690 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   691 but often produces more compact proof terms with less detours;
   692 
   693 * Pure/Provers/classical: simplified integration with pure rule
   694 attributes and methods; the classical "intro?/elim?/dest?"
   695 declarations coincide with the pure ones; the "rule" method no longer
   696 includes classically swapped intros; "intro" and "elim" methods no
   697 longer pick rules from the context; also got rid of ML declarations
   698 AddXIs/AddXEs/AddXDs; all of this has some potential for
   699 INCOMPATIBILITY;
   700 
   701 * Provers/classical: attribute 'swapped' produces classical inversions
   702 of introduction rules;
   703 
   704 * Provers/simplifier: 'simplified' attribute may refer to explicit
   705 rules instead of full simplifier context; 'iff' attribute handles
   706 conditional rules;
   707 
   708 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   709 
   710 * HOL: 'recdef' now fails on unfinished automated proofs, use
   711 "(permissive)" option to recover old behavior;
   712 
   713 * HOL: 'inductive' no longer features separate (collective) attributes
   714 for 'intros' (was found too confusing);
   715 
   716 * HOL: properly declared induction rules less_induct and
   717 wf_induct_rule;
   718 
   719 
   720 *** HOL ***
   721 
   722 * HOL: moved over to sane numeral syntax; the new policy is as
   723 follows:
   724 
   725   - 0 and 1 are polymorphic constants, which are defined on any
   726   numeric type (nat, int, real etc.);
   727 
   728   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   729   binary representation internally;
   730 
   731   - type nat has special constructor Suc, and generally prefers Suc 0
   732   over 1::nat and Suc (Suc 0) over 2::nat;
   733 
   734 This change may cause significant problems of INCOMPATIBILITY; here
   735 are some hints on converting existing sources:
   736 
   737   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   738   entities, so expressions involving "-" (unary or binary minus) need
   739   to be spaced properly;
   740 
   741   - existing occurrences of "1" may need to be constraint "1::nat" or
   742   even replaced by Suc 0; similar for old "2";
   743 
   744   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   745 
   746   - remove all special provisions on numerals in proofs;
   747 
   748 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   749 representation (depends on bin_arith_simps in the default context);
   750 
   751 * HOL: symbolic syntax for x^2 (numeral 2);
   752 
   753 * HOL: the class of all HOL types is now called "type" rather than
   754 "term"; INCOMPATIBILITY, need to adapt references to this type class
   755 in axclass/classes, instance/arities, and (usually rare) occurrences
   756 in typings (of consts etc.); internally the class is called
   757 "HOL.type", ML programs should refer to HOLogic.typeS;
   758 
   759 * HOL/record package improvements:
   760   - new derived operations "fields" to build a partial record section,
   761     "extend" to promote a fixed record to a record scheme, and
   762     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   763     declared as simp by default;
   764   - shared operations ("more", "fields", etc.) now need to be always
   765     qualified) --- potential INCOMPATIBILITY;
   766   - removed "make_scheme" operations (use "make" with "extend") --
   767     INCOMPATIBILITY;
   768   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   769   - provides cases/induct rules for use with corresponding Isar
   770     methods (for concrete records, record schemes, concrete more
   771     parts, and schematic more parts -- in that order);
   772   - internal definitions directly based on a light-weight abstract
   773     theory of product types over typedef rather than datatype;
   774 
   775 * HOL: generic code generator for generating executable ML code from
   776 specifications; specific support for HOL constructs such as inductive
   777 datatypes and sets, as well as recursive functions; can be invoked
   778 via 'generate_code' theory section;
   779 
   780 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   781 
   782 * HOL: consolidated and renamed several theories.  In particular:
   783         Ord.thy has been absorbed into HOL.thy
   784         String.thy has been absorbed into List.thy
   785 
   786 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   787 (beware of argument permutation!);
   788 
   789 * HOL: linorder_less_split superseded by linorder_cases;
   790 
   791 * HOL/List: "nodups" renamed to "distinct";
   792 
   793 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   794 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   795   - Ex_def has changed, now need to use some_eq_ex
   796 
   797 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   798 in this (rare) case use:
   799 
   800   delSWrapper "split_all_tac"
   801   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   802 
   803 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   804 MAY FAIL;
   805 
   806 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   807 Isabelle's type classes, ^ on functions and relations has too general
   808 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   809 necessary to attach explicit type constraints;
   810 
   811 * HOL/Relation: the prefix name of the infix "O" has been changed from
   812 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   813 renamed accordingly (eg "compI" -> "rel_compI").
   814 
   815 * HOL: syntax translations now work properly with numerals and records
   816 expressions;
   817 
   818 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   819 of "lam" -- INCOMPATIBILITY;
   820 
   821 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   822 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   823 renamed "Product_Type.unit";
   824 
   825 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   826 
   827 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   828 the "cases" method);
   829 
   830 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   831 Florian Kammüller);
   832 
   833 * HOL/IMP: updated and converted to new-style theory format; several
   834 parts turned into readable document, with proper Isar proof texts and
   835 some explanations (by Gerwin Klein);
   836 
   837 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   838 
   839 * HOL-Hyperreal is now a logic image;
   840 
   841 
   842 *** HOLCF ***
   843 
   844 * Isar: consts/constdefs supports mixfix syntax for continuous
   845 operations;
   846 
   847 * Isar: domain package adapted to new-style theory format, e.g. see
   848 HOLCF/ex/Dnat.thy;
   849 
   850 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   851 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   852 lift.induct_tac, always use UU instead of Undef;
   853 
   854 * HOLCF/IMP: updated and converted to new-style theory;
   855 
   856 
   857 *** ZF ***
   858 
   859 * Isar: proper integration of logic-specific tools and packages,
   860 including theory commands '(co)inductive', '(co)datatype',
   861 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   862 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   863 
   864 * theory Main no longer includes AC; for the Axiom of Choice, base
   865 your theory on Main_ZFC;
   866 
   867 * the integer library now covers quotients and remainders, with many
   868 laws relating division to addition, multiplication, etc.;
   869 
   870 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   871 typeless version of the formalism;
   872 
   873 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   874 format;
   875 
   876 * ZF/Induct: new directory for examples of inductive definitions,
   877 including theory Multiset for multiset orderings; converted to
   878 new-style theory format;
   879 
   880 * ZF: many new theorems about lists, ordinals, etc.;
   881 
   882 
   883 *** General ***
   884 
   885 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   886 variable proof controls level of detail: 0 = no proofs (only oracle
   887 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   888 also ref manual for further ML interfaces;
   889 
   890 * Pure/axclass: removed obsolete ML interface
   891 goal_subclass/goal_arity;
   892 
   893 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   894 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   895 separate tokens, so expressions involving minus need to be spaced
   896 properly;
   897 
   898 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   899 rather than "infixl" or "infixr";
   900 
   901 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   902 sort constraint specifications in type inference; e.g. "x::_::foo"
   903 ensures that the type of "x" is of sort "foo" (but not necessarily a
   904 type variable);
   905 
   906 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   907 control output of nested => (types); the default behavior is
   908 "type_brackets";
   909 
   910 * Pure/syntax: builtin parse translation for "_constify" turns valued
   911 tokens into AST constants;
   912 
   913 * Pure/syntax: prefer later declarations of translations and print
   914 translation functions; potential INCOMPATIBILITY: need to reverse
   915 multiple declarations for same syntax element constant;
   916 
   917 * Pure/show_hyps reset by default (in accordance to existing Isar
   918 practice);
   919 
   920 * Provers/classical: renamed addaltern to addafter, addSaltern to
   921 addSafter;
   922 
   923 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   924 as well;
   925 
   926 * system: tested support for MacOS X; should be able to get Isabelle +
   927 Proof General to work in a plain Terminal after installing Poly/ML
   928 (e.g. from the Isabelle distribution area) and GNU bash alone
   929 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   930 support requires further installations, e.g. from
   931 http://fink.sourceforge.net/);
   932 
   933 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   934 
   935 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   936 of 40 MB), cf. ML_OPTIONS;
   937 
   938 * system: Proof General keywords specification is now part of the
   939 Isabelle distribution (see etc/isar-keywords.el);
   940 
   941 * system: support for persistent Proof General sessions (refrain from
   942 outdating all loaded theories on startup); user may create writable
   943 logic images like this: ``isabelle -q HOL Test'';
   944 
   945 * system: smart selection of Isabelle process versus Isabelle
   946 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   947 run both "isabelle" and "Isabelle" even if file names are badly
   948 damaged (executable inspects the case of the first letter of its own
   949 name); added separate "isabelle-process" and "isabelle-interface";
   950 
   951 * system: refrain from any attempt at filtering input streams; no
   952 longer support ``8bit'' encoding of old isabelle font, instead proper
   953 iso-latin characters may now be used; the related isatools
   954 "symbolinput" and "nonascii" have disappeared as well;
   955 
   956 * system: removed old "xterm" interface (the print modes "xterm" and
   957 "xterm_color" are still available for direct use in a suitable
   958 terminal);
   959 
   960 
   961 
   962 New in Isabelle99-2 (February 2001)
   963 -----------------------------------
   964 
   965 *** Overview of INCOMPATIBILITIES ***
   966 
   967 * HOL: please note that theories in the Library and elsewhere often use the
   968 new-style (Isar) format; to refer to their theorems in an ML script you must
   969 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   970 
   971 * HOL: inductive package no longer splits induction rule aggressively,
   972 but only as far as specified by the introductions given; the old
   973 format may be recovered via ML function complete_split_rule or attribute
   974 'split_rule (complete)';
   975 
   976 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   977 gfp_Tarski to gfp_unfold;
   978 
   979 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   980 
   981 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   982 relation); infix "^^" has been renamed "``"; infix "``" has been
   983 renamed "`"; "univalent" has been renamed "single_valued";
   984 
   985 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   986 operation;
   987 
   988 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   989 
   990 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   991 
   992 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   993 consequence, it is no longer monotonic wrt. the local goal context
   994 (which is now passed through the inductive cases);
   995 
   996 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   997 \<gg> to \<ggreater>;
   998 
   999 
  1000 *** Document preparation ***
  1001 
  1002 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1003 available: are "it" for near math-mode best-style output, "sl" for
  1004 slanted text style, and "tt" for plain type-writer; if no
  1005 \isabellestyle command is given, output is according to slanted
  1006 type-writer);
  1007 
  1008 * support sub/super scripts (for single symbols only), input syntax is
  1009 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1010 
  1011 * some more standard symbols; see Appendix A of the system manual for
  1012 the complete list of symbols defined in isabellesym.sty;
  1013 
  1014 * improved isabelle style files; more abstract symbol implementation
  1015 (should now use \isamath{...} and \isatext{...} in custom symbol
  1016 definitions);
  1017 
  1018 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1019 state; Note that presentation of goal states does not conform to
  1020 actual human-readable proof documents.  Please do not include goal
  1021 states into document output unless you really know what you are doing!
  1022 
  1023 * proper indentation of antiquoted output with proportional LaTeX
  1024 fonts;
  1025 
  1026 * no_document ML operator temporarily disables LaTeX document
  1027 generation;
  1028 
  1029 * isatool unsymbolize tunes sources for plain ASCII communication;
  1030 
  1031 
  1032 *** Isar ***
  1033 
  1034 * Pure: Isar now suffers initial goal statements to contain unbound
  1035 schematic variables (this does not conform to actual readable proof
  1036 documents, due to unpredictable outcome and non-compositional proof
  1037 checking); users who know what they are doing may use schematic goals
  1038 for Prolog-style synthesis of proven results;
  1039 
  1040 * Pure: assumption method (an implicit finishing) now handles actual
  1041 rules as well;
  1042 
  1043 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1044 initial goal, declare "that" only as Pure intro (only for single
  1045 steps); the "that" rule assumption may now be involved in implicit
  1046 finishing, thus ".." becomes a feasible for trivial obtains;
  1047 
  1048 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1049 instance proofs may be performed by "..";
  1050 
  1051 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1052 statements as well;
  1053 
  1054 * Pure: more robust selection of calculational rules;
  1055 
  1056 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1057 rule (as well as the assumption rule);
  1058 
  1059 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1060 lemmas, using the graph browser tool;
  1061 
  1062 * Pure: predict failure of "show" in interactive mode;
  1063 
  1064 * Pure: 'thms_containing' now takes actual terms as arguments;
  1065 
  1066 * HOL: improved method 'induct' --- now handles non-atomic goals
  1067 (potential INCOMPATIBILITY); tuned error handling;
  1068 
  1069 * HOL: cases and induct rules now provide explicit hints about the
  1070 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1071 any remaining facts are inserted into the goal verbatim;
  1072 
  1073 * HOL: local contexts (aka cases) may now contain term bindings as
  1074 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1075 the result to be shown in each case;
  1076 
  1077 * HOL: added 'recdef_tc' command;
  1078 
  1079 * isatool convert assists in eliminating legacy ML scripts;
  1080 
  1081 
  1082 *** HOL ***
  1083 
  1084 * HOL/Library: a collection of generic theories to be used together
  1085 with main HOL; the theory loader path already includes this directory
  1086 by default; the following existing theories have been moved here:
  1087 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1088 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1089 
  1090 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1091 modelling and verification task performed in Isabelle/HOL +
  1092 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1093 
  1094 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1095 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1096 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1097 'domain', this makes the theory consistent with mathematical
  1098 literature;
  1099 
  1100 * HOL basics: added overloaded operations "inverse" and "divide"
  1101 (infix "/"), syntax for generic "abs" operation, generic summation
  1102 operator \<Sum>;
  1103 
  1104 * HOL/typedef: simplified package, provide more useful rules (see also
  1105 HOL/subset.thy);
  1106 
  1107 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1108 now expressed as a proper nested rule (old-style tactic scripts may
  1109 require atomize_strip_tac to cope with non-atomic premises);
  1110 
  1111 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1112 to "split_conv" (old name still available for compatibility);
  1113 
  1114 * HOL: improved concrete syntax for strings (e.g. allows translation
  1115 rules with string literals);
  1116 
  1117 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1118  and Fleuriot's mechanization of analysis, including the transcendental
  1119  functions for the reals;
  1120 
  1121 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1122 
  1123 
  1124 *** CTT ***
  1125 
  1126 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1127 "lam" is displayed as TWO lambda-symbols
  1128 
  1129 * CTT: theory Main now available, containing everything (that is, Bool
  1130 and Arith);
  1131 
  1132 
  1133 *** General ***
  1134 
  1135 * Pure: the Simplifier has been implemented properly as a derived rule
  1136 outside of the actual kernel (at last!); the overall performance
  1137 penalty in practical applications is about 50%, while reliability of
  1138 the Isabelle inference kernel has been greatly improved;
  1139 
  1140 * print modes "brackets" and "no_brackets" control output of nested =>
  1141 (types) and ==> (props); the default behaviour is "brackets";
  1142 
  1143 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1144 as assumptions as well;
  1145 
  1146 * system: support Poly/ML 4.0;
  1147 
  1148 * system: isatool install handles KDE version 1 or 2;
  1149 
  1150 
  1151 
  1152 New in Isabelle99-1 (October 2000)
  1153 ----------------------------------
  1154 
  1155 *** Overview of INCOMPATIBILITIES ***
  1156 
  1157 * HOL: simplification of natural numbers is much changed; to partly
  1158 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1159 issue the following ML commands:
  1160 
  1161   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1162   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1163 
  1164 * HOL: simplification no longer dives into case-expressions; this is
  1165 controlled by "t.weak_case_cong" for each datatype t;
  1166 
  1167 * HOL: nat_less_induct renamed to less_induct;
  1168 
  1169 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1170 fixsome to patch .thy and .ML sources automatically;
  1171 
  1172   select_equality  -> some_equality
  1173   select_eq_Ex     -> some_eq_ex
  1174   selectI2EX       -> someI2_ex
  1175   selectI2         -> someI2
  1176   selectI          -> someI
  1177   select1_equality -> some1_equality
  1178   Eps_sym_eq       -> some_sym_eq_trivial
  1179   Eps_eq           -> some_eq_trivial
  1180 
  1181 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1182 
  1183 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1184 instead);
  1185 
  1186 * HOL: the recursion equations generated by 'recdef' are now called
  1187 f.simps instead of f.rules;
  1188 
  1189 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1190 
  1191 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1192 sometimes be needed;
  1193 
  1194 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1195 
  1196 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1197 
  1198 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1199 product is now "<*>" instead of "Times"; the lexicographic product is
  1200 now "<*lex*>" instead of "**";
  1201 
  1202 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1203 of main HOL, but was unused); better use HOL's datatype package;
  1204 
  1205 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1206 the old syntax may be recovered as follows:
  1207 
  1208   syntax (symbols)
  1209     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1210       (infixl "\\<oplus>" 100)
  1211 
  1212 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1213 
  1214 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1215 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1216 internally;
  1217 
  1218 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1219 changed from A/r to A//r;
  1220 
  1221 * ZF: new treatment of arithmetic (nat & int) may break some old
  1222 proofs;
  1223 
  1224 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1225 rulify -> rule_format, elimify -> elim_format, ...);
  1226 
  1227 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1228 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1229 should have to change intro!! to intro? only); replaced "delrule" by
  1230 "rule del";
  1231 
  1232 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1233 
  1234 * Provers: strengthened force_tac by using new first_best_tac;
  1235 
  1236 * LaTeX document preparation: several changes of isabelle.sty (see
  1237 lib/texinputs);
  1238 
  1239 
  1240 *** Document preparation ***
  1241 
  1242 * formal comments (text blocks etc.) in new-style theories may now
  1243 contain antiquotations of thm/prop/term/typ/text to be presented
  1244 according to latex print mode; concrete syntax is like this:
  1245 @{term[show_types] "f(x) = a + x"};
  1246 
  1247 * isatool mkdir provides easy setup of Isabelle session directories,
  1248 including proper document sources;
  1249 
  1250 * generated LaTeX sources are now deleted after successful run
  1251 (isatool document -c); may retain a copy somewhere else via -D option
  1252 of isatool usedir;
  1253 
  1254 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1255 style files, achieving self-contained LaTeX sources and simplifying
  1256 LaTeX debugging;
  1257 
  1258 * old-style theories now produce (crude) LaTeX output as well;
  1259 
  1260 * browser info session directories are now self-contained (may be put
  1261 on WWW server seperately); improved graphs of nested sessions; removed
  1262 graph for 'all sessions';
  1263 
  1264 * several improvements in isabelle style files; \isabellestyle{it}
  1265 produces fake math mode output; \isamarkupheader is now \section by
  1266 default; see lib/texinputs/isabelle.sty etc.;
  1267 
  1268 
  1269 *** Isar ***
  1270 
  1271 * Isar/Pure: local results and corresponding term bindings are now
  1272 subject to Hindley-Milner polymorphism (similar to ML); this
  1273 accommodates incremental type-inference very nicely;
  1274 
  1275 * Isar/Pure: new derived language element 'obtain' supports
  1276 generalized existence reasoning;
  1277 
  1278 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1279 support accumulation of results, without applying any rules yet;
  1280 useful to collect intermediate results without explicit name
  1281 references, and for use with transitivity rules with more than 2
  1282 premises;
  1283 
  1284 * Isar/Pure: scalable support for case-analysis type proofs: new
  1285 'case' language element refers to local contexts symbolically, as
  1286 produced by certain proof methods; internally, case names are attached
  1287 to theorems as "tags";
  1288 
  1289 * Isar/Pure: theory command 'hide' removes declarations from
  1290 class/type/const name spaces;
  1291 
  1292 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1293 indicate potential overloading;
  1294 
  1295 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1296 
  1297 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1298 "{a,b,c}" instead of {a,b,c};
  1299 
  1300 * Isar/Pure now provides its own version of intro/elim/dest
  1301 attributes; useful for building new logics, but beware of confusion
  1302 with the version in Provers/classical;
  1303 
  1304 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1305 case name 'antecedent';
  1306 
  1307 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1308 to the current context is now done automatically);
  1309 
  1310 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1311 for definining proof methods in ML;
  1312 
  1313 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1314 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1315 most cases, one should have to change intro!! to intro? only);
  1316 replaced "delrule" by "rule del";
  1317 
  1318 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1319 'symmetric' attribute (the latter supercedes [RS sym]);
  1320 
  1321 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1322 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1323 well (including splits);
  1324 
  1325 * Isar/Provers: Simplifier and Classical methods now support all kind
  1326 of modifiers used in the past, including 'cong', 'iff', etc.
  1327 
  1328 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1329 of Simplifier and Classical reasoner);
  1330 
  1331 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1332 now support named cases; major packages (inductive, datatype, primrec,
  1333 recdef) support case names and properly name parameters;
  1334 
  1335 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1336 monotonicity conditions are extracted to be proven at end of
  1337 calculations;
  1338 
  1339 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1340 method anyway;
  1341 
  1342 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1343 split_if split_if_asm; datatype package provides theorems foo.splits =
  1344 foo.split foo.split_asm for each datatype;
  1345 
  1346 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1347 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1348 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1349 use "(cases (simplified))" method in proper proof texts);
  1350 
  1351 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1352 
  1353 * Isar: names of theorems etc. may be natural numbers as well;
  1354 
  1355 * Isar: 'pr' command: optional arguments for goals_limit and
  1356 ProofContext.prems_limit; no longer prints theory contexts, but only
  1357 proof states;
  1358 
  1359 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1360 additional print modes to be specified; e.g. "pr(latex)" will print
  1361 proof state according to the Isabelle LaTeX style;
  1362 
  1363 * Isar: improved support for emulating tactic scripts, including proof
  1364 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1365 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1366 (for HOL datatypes);
  1367 
  1368 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1369 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1370 'proof method scripts' have to be in depth-first order;
  1371 
  1372 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1373 
  1374 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1375 should instead use individual commands for printing items
  1376 (print_commands, print_methods etc.);
  1377 
  1378 * Isar: added 'nothing' --- the empty list of theorems;
  1379 
  1380 
  1381 *** HOL ***
  1382 
  1383 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1384 corresponding virtual machine and a specification of its bytecode
  1385 verifier and a lightweight bytecode verifier, including proofs of
  1386 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1387 Cornelia Pusch (see also the homepage of project Bali at
  1388 http://isabelle.in.tum.de/Bali/);
  1389 
  1390 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1391 Clemens Ballarin;
  1392 
  1393 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1394 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1395 Rasmussen;
  1396 
  1397 * HOL/Lattice: fundamental concepts of lattice theory and order
  1398 structures, including duals, properties of bounds versus algebraic
  1399 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1400 Theorem for complete lattices etc.; may also serve as a demonstration
  1401 for abstract algebraic reasoning using axiomatic type classes, and
  1402 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1403 
  1404 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1405 von Oheimb;
  1406 
  1407 * HOL/IMPP: extension of IMP with local variables and mutually
  1408 recursive procedures, by David von Oheimb;
  1409 
  1410 * HOL/Lambda: converted into new-style theory and document;
  1411 
  1412 * HOL/ex/Multiquote: example of multiple nested quotations and
  1413 anti-quotations -- basically a generalized version of de-Bruijn
  1414 representation; very useful in avoiding lifting of operations;
  1415 
  1416 * HOL/record: added general record equality rule to simpset; fixed
  1417 select-update simplification procedure to handle extended records as
  1418 well; admit "r" as field name;
  1419 
  1420 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1421 other numeric types and also as the identity of groups, rings, etc.;
  1422 
  1423 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1424 Types nat and int belong to this axclass;
  1425 
  1426 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1427    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1428    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1429   two terms #m*u and #n*u are replaced by #(m+n)*u
  1430     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1431   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1432     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1433 
  1434 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1435 powerful prover for predicate logic but knows nothing of clasets; see
  1436 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1437 
  1438 * HOL: new version of "case_tac" subsumes both boolean case split and
  1439 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1440 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1441 
  1442 * HOL: simplification no longer dives into case-expressions: only the
  1443 selector expression is simplified, but not the remaining arms; to
  1444 enable full simplification of case-expressions for datatype t, you may
  1445 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1446 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1447 
  1448 * HOL/recdef: the recursion equations generated by 'recdef' for
  1449 function 'f' are now called f.simps instead of f.rules; if all
  1450 termination conditions are proved automatically, these simplification
  1451 rules are added to the simpset, as in primrec; rules may be named
  1452 individually as well, resulting in a separate list of theorems for
  1453 each equation;
  1454 
  1455 * HOL/While is a new theory that provides a while-combinator. It
  1456 permits the definition of tail-recursive functions without the
  1457 provision of a termination measure. The latter is necessary once the
  1458 invariant proof rule for while is applied.
  1459 
  1460 * HOL: new (overloaded) notation for the set of elements below/above
  1461 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1462 
  1463 * HOL: theorems impI, allI, ballI bound as "strip";
  1464 
  1465 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1466 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1467 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1468 
  1469 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1470 
  1471 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1472 main HOL, but was unused);
  1473 
  1474 * HOL: fewer consts declared as global (e.g. have to refer to
  1475 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1476 
  1477 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1478 in case of overlap with user translations (e.g. judgements over
  1479 tuples); (note that the underlying logical represenation is still
  1480 bogus);
  1481 
  1482 
  1483 *** ZF ***
  1484 
  1485 * ZF: simplification automatically cancels common terms in arithmetic
  1486 expressions over nat and int;
  1487 
  1488 * ZF: new treatment of nat to minimize type-checking: all operators
  1489 coerce their operands to a natural number using the function natify,
  1490 making the algebraic laws unconditional;
  1491 
  1492 * ZF: as above, for int: operators coerce their operands to an integer
  1493 using the function intify;
  1494 
  1495 * ZF: the integer library now contains many of the usual laws for the
  1496 orderings, including $<=, and monotonicity laws for $+ and $*;
  1497 
  1498 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1499 simplification;
  1500 
  1501 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1502 to the simplifier and classical reasoner simultaneously;
  1503 
  1504 
  1505 *** General ***
  1506 
  1507 * Provers: blast_tac now handles actual object-logic rules as
  1508 assumptions; note that auto_tac uses blast_tac internally as well;
  1509 
  1510 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1511 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1512 
  1513 * Provers: delrules now handles destruct rules as well (no longer need
  1514 explicit make_elim);
  1515 
  1516 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1517   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1518 use instead the strong form,
  1519   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1520 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1521 from destruct-rules;
  1522 
  1523 * Provers: Simplifier.easy_setup provides a fast path to basic
  1524 Simplifier setup for new object-logics;
  1525 
  1526 * Pure: AST translation rules no longer require constant head on LHS;
  1527 
  1528 * Pure: improved name spaces: ambiguous output is qualified; support
  1529 for hiding of names;
  1530 
  1531 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1532 XSYMBOL_HOME; no longer need to do manual configuration in most
  1533 situations;
  1534 
  1535 * system: compression of ML heaps images may now be controlled via -c
  1536 option of isabelle and isatool usedir (currently only observed by
  1537 Poly/ML);
  1538 
  1539 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1540 useful for remote X11);
  1541 
  1542 * system: provide TAGS file for Isabelle sources;
  1543 
  1544 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1545 order;
  1546 
  1547 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1548 timing flag supersedes proof_timing and Toplevel.trace;
  1549 
  1550 * ML: new combinators |>> and |>>> for incremental transformations
  1551 with secondary results (e.g. certain theory extensions):
  1552 
  1553 * ML: PureThy.add_defs gets additional argument to indicate potential
  1554 overloading (usually false);
  1555 
  1556 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1557 results;
  1558 
  1559 
  1560 
  1561 New in Isabelle99 (October 1999)
  1562 --------------------------------
  1563 
  1564 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1565 
  1566 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1567 are no longer simplified.  (This allows the simplifier to unfold recursive
  1568 functional programs.)  To restore the old behaviour, declare
  1569 
  1570     Delcongs [if_weak_cong];
  1571 
  1572 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1573 complement;
  1574 
  1575 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1576 
  1577 * HOL/datatype: mutual_induct_tac no longer exists --
  1578   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1579 
  1580 * HOL/typedef: fixed type inference for representing set; type
  1581 arguments now have to occur explicitly on the rhs as type constraints;
  1582 
  1583 * ZF: The con_defs part of an inductive definition may no longer refer
  1584 to constants declared in the same theory;
  1585 
  1586 * HOL, ZF: the function mk_cases, generated by the inductive
  1587 definition package, has lost an argument.  To simplify its result, it
  1588 uses the default simpset instead of a supplied list of theorems.
  1589 
  1590 * HOL/List: the constructors of type list are now Nil and Cons;
  1591 
  1592 * Simplifier: the type of the infix ML functions
  1593         setSSolver addSSolver setSolver addSolver
  1594 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1595 for packaging solvers. A solver is created via
  1596         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1597 where the string argument is only a comment.
  1598 
  1599 
  1600 *** Proof tools ***
  1601 
  1602 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1603 decision procedure for linear arithmetic. Currently it is used for
  1604 types `nat', `int', and `real' in HOL (see below); it can, should and
  1605 will be instantiated for other types and logics as well.
  1606 
  1607 * The simplifier now accepts rewrite rules with flexible heads, eg
  1608      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1609   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1610   matching.
  1611 
  1612 
  1613 *** General ***
  1614 
  1615 * New Isabelle/Isar subsystem provides an alternative to traditional
  1616 tactical theorem proving; together with the ProofGeneral/isar user
  1617 interface it offers an interactive environment for developing human
  1618 readable proof documents (Isar == Intelligible semi-automated
  1619 reasoning); for further information see isatool doc isar-ref,
  1620 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1621 
  1622 * improved and simplified presentation of theories: better HTML markup
  1623 (including colors), graph views in several sizes; isatool usedir now
  1624 provides a proper interface for user theories (via -P option); actual
  1625 document preparation based on (PDF)LaTeX is available as well (for
  1626 new-style theories only); see isatool doc system for more information;
  1627 
  1628 * native support for Proof General, both for classic Isabelle and
  1629 Isabelle/Isar;
  1630 
  1631 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1632 using the graph browser tool;
  1633 
  1634 * Isabelle manuals now also available as PDF;
  1635 
  1636 * theory loader rewritten from scratch (may not be fully
  1637 bug-compatible); old loadpath variable has been replaced by show_path,
  1638 add_path, del_path, reset_path functions; new operations such as
  1639 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1640 isatool doc ref);
  1641 
  1642 * improved isatool install: option -k creates KDE application icon,
  1643 option -p DIR installs standalone binaries;
  1644 
  1645 * added ML_PLATFORM setting (useful for cross-platform installations);
  1646 more robust handling of platform specific ML images for SML/NJ;
  1647 
  1648 * the settings environment is now statically scoped, i.e. it is never
  1649 created again in sub-processes invoked from isabelle, isatool, or
  1650 Isabelle;
  1651 
  1652 * path element specification '~~' refers to '$ISABELLE_HOME';
  1653 
  1654 * in locales, the "assumes" and "defines" parts may be omitted if
  1655 empty;
  1656 
  1657 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1658 long arrows);
  1659 
  1660 * new print_mode "HTML";
  1661 
  1662 * new flag show_tags controls display of tags of theorems (which are
  1663 basically just comments that may be attached by some tools);
  1664 
  1665 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1666 mode and goal output format:
  1667 
  1668 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1669 244c244
  1670 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1671 ---
  1672 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1673 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1674 181c181
  1675 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1676 ---
  1677 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1678 
  1679 * function bind_thms stores lists of theorems (cf. bind_thm);
  1680 
  1681 * new shorthand tactics ftac, eatac, datac, fatac;
  1682 
  1683 * qed (and friends) now accept "" as result name; in that case the
  1684 theorem is not stored, but proper checks and presentation of the
  1685 result still apply;
  1686 
  1687 * theorem database now also indexes constants "Trueprop", "all",
  1688 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1689 
  1690 
  1691 *** HOL ***
  1692 
  1693 ** HOL arithmetic **
  1694 
  1695 * There are now decision procedures for linear arithmetic over nat and
  1696 int:
  1697 
  1698 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1699 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1700 are treated as atomic; subformulae not involving type `nat' or `int'
  1701 are ignored; quantified subformulae are ignored unless they are
  1702 positive universal or negative existential. The tactic has to be
  1703 invoked by hand and can be a little bit slow. In particular, the
  1704 running time is exponential in the number of occurrences of `min' and
  1705 `max', and `-' on `nat'.
  1706 
  1707 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1708 (negated) (in)equalities among the premises and the conclusion into
  1709 account (i.e. no compound formulae) and does not know about `min' and
  1710 `max', and `-' on `nat'. It is fast and is used automatically by the
  1711 simplifier.
  1712 
  1713 NB: At the moment, these decision procedures do not cope with mixed
  1714 nat/int formulae where the two parts interact, such as `m < n ==>
  1715 int(m) < int(n)'.
  1716 
  1717 * HOL/Numeral provides a generic theory of numerals (encoded
  1718 efficiently as bit strings); setup for types nat/int/real is in place;
  1719 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1720 int, existing theories and proof scripts may require a few additional
  1721 type constraints;
  1722 
  1723 * integer division and remainder can now be performed on constant
  1724 arguments;
  1725 
  1726 * many properties of integer multiplication, division and remainder
  1727 are now available;
  1728 
  1729 * An interface to the Stanford Validity Checker (SVC) is available through the
  1730 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1731 are proved automatically.  SVC must be installed separately, and its results
  1732 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1733 invocation of the underlying oracle).  For SVC see
  1734   http://verify.stanford.edu/SVC
  1735 
  1736 * IsaMakefile: the HOL-Real target now builds an actual image;
  1737 
  1738 
  1739 ** HOL misc **
  1740 
  1741 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1742 (in Isabelle/Isar) -- by Gertrud Bauer;
  1743 
  1744 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1745 analysis for assembly languages with subtypes;
  1746 
  1747 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1748 -- avoids syntactic ambiguities and treats state, transition, and
  1749 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1750 changed syntax and (many) tactics;
  1751 
  1752 * HOL/inductive: Now also handles more general introduction rules such
  1753   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1754   theorems are now maintained within the theory (maintained via the
  1755   "mono" attribute);
  1756 
  1757 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1758   (using function types) such as
  1759 
  1760   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1761 
  1762 * HOL/record: record_simproc (part of the default simpset) takes care
  1763 of selectors applied to updated records; record_split_tac is no longer
  1764 part of the default claset; update_defs may now be removed from the
  1765 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1766 
  1767   claset_ref () := claset() addSWrapper record_split_wrapper;
  1768   Delsimprocs [record_simproc]
  1769 
  1770 * HOL/typedef: fixed type inference for representing set; type
  1771 arguments now have to occur explicitly on the rhs as type constraints;
  1772 
  1773 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1774 names rather than an ML expression;
  1775 
  1776 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1777 supplied later.  Program schemes can be defined, such as
  1778     "While B C s = (if B s then While B C (C s) else s)"
  1779 where the well-founded relation can be chosen after B and C have been given.
  1780 
  1781 * HOL/List: the constructors of type list are now Nil and Cons;
  1782 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1783 course, ML tools referring to List.list.op # etc. have to be adapted;
  1784 
  1785 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1786 disabled by default; run isabelle with option -m HOL to get back to
  1787 the original Gordon/HOL-style output;
  1788 
  1789 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1790 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1791 
  1792 * HOL basic syntax simplified (more orthogonal): all variants of
  1793 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1794 Eps operator is provided as well: "SOME x. P[x]";
  1795 
  1796 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1797 
  1798 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1799 thus available for user theories;
  1800 
  1801 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1802 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1803 time;
  1804 
  1805 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1806 several times and then mp;
  1807 
  1808 
  1809 *** LK ***
  1810 
  1811 * the notation <<...>> is now available as a notation for sequences of
  1812 formulas;
  1813 
  1814 * the simplifier is now installed
  1815 
  1816 * the axiom system has been generalized (thanks to Soren Heilmann)
  1817 
  1818 * the classical reasoner now has a default rule database
  1819 
  1820 
  1821 *** ZF ***
  1822 
  1823 * new primrec section allows primitive recursive functions to be given
  1824 directly (as in HOL) over datatypes and the natural numbers;
  1825 
  1826 * new tactics induct_tac and exhaust_tac for induction (or case
  1827 analysis) over datatypes and the natural numbers;
  1828 
  1829 * the datatype declaration of type T now defines the recursor T_rec;
  1830 
  1831 * simplification automatically does freeness reasoning for datatype
  1832 constructors;
  1833 
  1834 * automatic type-inference, with AddTCs command to insert new
  1835 type-checking rules;
  1836 
  1837 * datatype introduction rules are now added as Safe Introduction rules
  1838 to the claset;
  1839 
  1840 * the syntax "if P then x else y" is now available in addition to
  1841 if(P,x,y);
  1842 
  1843 
  1844 *** Internal programming interfaces ***
  1845 
  1846 * tuned simplifier trace output; new flag debug_simp;
  1847 
  1848 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1849 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1850 
  1851 * AxClass.axclass_tac lost the theory argument;
  1852 
  1853 * tuned current_goals_markers semantics: begin / end goal avoids
  1854 printing empty lines;
  1855 
  1856 * removed prs and prs_fn hook, which was broken because it did not
  1857 include \n in its semantics, forcing writeln to add one
  1858 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1859 string -> unit if you really want to output text without newline;
  1860 
  1861 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1862 plain output, interface builders may have to enable 'isabelle_font'
  1863 mode to get Isabelle font glyphs as before;
  1864 
  1865 * refined token_translation interface; INCOMPATIBILITY: output length
  1866 now of type real instead of int;
  1867 
  1868 * theory loader actions may be traced via new ThyInfo.add_hook
  1869 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1870 your own database of information attached to *whole* theories -- as
  1871 opposed to intra-theory data slots offered via TheoryDataFun;
  1872 
  1873 * proper handling of dangling sort hypotheses (at last!);
  1874 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1875 extra sort hypotheses that can be witnessed from the type signature;
  1876 the force_strip_shyps flag is gone, any remaining shyps are simply
  1877 left in the theorem (with a warning issued by strip_shyps_warning);
  1878 
  1879 
  1880 
  1881 New in Isabelle98-1 (October 1998)
  1882 ----------------------------------
  1883 
  1884 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1885 
  1886 * several changes of automated proof tools;
  1887 
  1888 * HOL: major changes to the inductive and datatype packages, including
  1889 some minor incompatibilities of theory syntax;
  1890 
  1891 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1892 called `inj_on';
  1893 
  1894 * HOL: removed duplicate thms in Arith:
  1895   less_imp_add_less  should be replaced by  trans_less_add1
  1896   le_imp_add_le      should be replaced by  trans_le_add1
  1897 
  1898 * HOL: unary minus is now overloaded (new type constraints may be
  1899 required);
  1900 
  1901 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1902 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1903 now taken as an integer constant.
  1904 
  1905 * Pure: ML function 'theory_of' renamed to 'theory';
  1906 
  1907 
  1908 *** Proof tools ***
  1909 
  1910 * Simplifier:
  1911   1. Asm_full_simp_tac is now more aggressive.
  1912      1. It will sometimes reorient premises if that increases their power to
  1913         simplify.
  1914      2. It does no longer proceed strictly from left to right but may also
  1915         rotate premises to achieve further simplification.
  1916      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1917      old Asm_full_simp_tac in that it does not rotate premises.
  1918   2. The simplifier now knows a little bit about nat-arithmetic.
  1919 
  1920 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1921 allows for selected deletion of wrappers, by introduction of names for
  1922 wrapper functionals.  This implies that addbefore, addSbefore,
  1923 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1924 and that adding two tactics with the same name overwrites the first
  1925 one (emitting a warning).
  1926   type wrapper = (int -> tactic) -> (int -> tactic)
  1927   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1928   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1929   delWrapper, delSWrapper: claset *  string            -> claset
  1930   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1931 
  1932 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1933 semantics; addbefore now affects only the unsafe part of step_tac
  1934 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1935 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1936 by Force_tac;
  1937 
  1938 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1939 compWrapper; added safe wrapper (and access functions for it);
  1940 
  1941 * HOL/split_all_tac is now much faster and fails if there is nothing
  1942 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1943 and the names of the automatically generated variables have changed.
  1944 split_all_tac has moved within claset() from unsafe wrappers to safe
  1945 wrappers, which means that !!-bound variables are split much more
  1946 aggressively, and safe_tac and clarify_tac now split such variables.
  1947 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1948 Note: the same holds for record_split_tac, which does the job of
  1949 split_all_tac for record fields.
  1950 
  1951 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1952 permanently to the default simpset using Addsplits just like
  1953 Addsimps. They can be removed via Delsplits just like
  1954 Delsimps. Lower-case versions are also available.
  1955 
  1956 * HOL/Simplifier: The rule split_if is now part of the default
  1957 simpset. This means that the simplifier will eliminate all occurrences
  1958 of if-then-else in the conclusion of a goal. To prevent this, you can
  1959 either remove split_if completely from the default simpset by
  1960 `Delsplits [split_if]' or remove it in a specific call of the
  1961 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1962 other case splitting rules to/from the default simpset: every datatype
  1963 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1964 t is the name of the datatype).
  1965 
  1966 * Classical reasoner / Simplifier combination: new force_tac (and
  1967 derivatives Force_tac, force) combines rewriting and classical
  1968 reasoning (and whatever other tools) similarly to auto_tac, but is
  1969 aimed to solve the given subgoal completely.
  1970 
  1971 
  1972 *** General ***
  1973 
  1974 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1975 and `goalw': the theory is no longer needed as an explicit argument -
  1976 the current theory context is used; assumptions are no longer returned
  1977 at the ML-level unless one of them starts with ==> or !!; it is
  1978 recommended to convert to these new commands using isatool fixgoal
  1979 (backup your sources first!);
  1980 
  1981 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1982 the current theory context, and 'theory' to lookup stored theories;
  1983 
  1984 * new theory section 'locale' for declaring constants, assumptions and
  1985 definitions that have local scope;
  1986 
  1987 * new theory section 'nonterminals' for purely syntactic types;
  1988 
  1989 * new theory section 'setup' for generic ML setup functions
  1990 (e.g. package initialization);
  1991 
  1992 * the distribution now includes Isabelle icons: see
  1993 lib/logo/isabelle-{small,tiny}.xpm;
  1994 
  1995 * isatool install - install binaries with absolute references to
  1996 ISABELLE_HOME/bin;
  1997 
  1998 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1999 
  2000 * print mode 'emacs' reserved for Isamode;
  2001 
  2002 * support multiple print (ast) translations per constant name;
  2003 
  2004 * theorems involving oracles are now printed with a suffixed [!];
  2005 
  2006 
  2007 *** HOL ***
  2008 
  2009 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2010 
  2011 * HOL/inductive package reorganized and improved: now supports mutual
  2012 definitions such as
  2013 
  2014   inductive EVEN ODD
  2015     intrs
  2016       null "0 : EVEN"
  2017       oddI "n : EVEN ==> Suc n : ODD"
  2018       evenI "n : ODD ==> Suc n : EVEN"
  2019 
  2020 new theorem list "elims" contains an elimination rule for each of the
  2021 recursive sets; inductive definitions now handle disjunctive premises
  2022 correctly (also ZF);
  2023 
  2024 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2025 "mutual_induct" no longer exists - the induction rule is always
  2026 contained in "induct";
  2027 
  2028 
  2029 * HOL/datatype package re-implemented and greatly improved: now
  2030 supports mutually recursive datatypes such as
  2031 
  2032   datatype
  2033     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2034             | SUM ('a aexp) ('a aexp)
  2035             | DIFF ('a aexp) ('a aexp)
  2036             | NUM 'a
  2037   and
  2038     'a bexp = LESS ('a aexp) ('a aexp)
  2039             | AND ('a bexp) ('a bexp)
  2040             | OR ('a bexp) ('a bexp)
  2041 
  2042 as well as indirectly recursive datatypes such as
  2043 
  2044   datatype
  2045     ('a, 'b) term = Var 'a
  2046                   | App 'b ((('a, 'b) term) list)
  2047 
  2048 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2049 induction on mutually / indirectly recursive datatypes.
  2050 
  2051 Primrec equations are now stored in theory and can be accessed via
  2052 <function_name>.simps.
  2053 
  2054 INCOMPATIBILITIES:
  2055 
  2056   - Theories using datatypes must now have theory Datatype as an
  2057     ancestor.
  2058   - The specific <typename>.induct_tac no longer exists - use the
  2059     generic induct_tac instead.
  2060   - natE has been renamed to nat.exhaust - use exhaust_tac
  2061     instead of res_inst_tac ... natE. Note that the variable
  2062     names in nat.exhaust differ from the names in natE, this
  2063     may cause some "fragile" proofs to fail.
  2064   - The theorems split_<typename>_case and split_<typename>_case_asm
  2065     have been renamed to <typename>.split and <typename>.split_asm.
  2066   - Since default sorts of type variables are now handled correctly,
  2067     some datatype definitions may have to be annotated with explicit
  2068     sort constraints.
  2069   - Primrec definitions no longer require function name and type
  2070     of recursive argument.
  2071 
  2072 Consider using isatool fixdatatype to adapt your theories and proof
  2073 scripts to the new package (backup your sources first!).
  2074 
  2075 
  2076 * HOL/record package: considerably improved implementation; now
  2077 includes concrete syntax for record types, terms, updates; theorems
  2078 for surjective pairing and splitting !!-bound record variables; proof
  2079 support is as follows:
  2080 
  2081   1) standard conversions (selectors or updates applied to record
  2082 constructor terms) are part of the standard simpset;
  2083 
  2084   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2085 made part of standard simpset and claset via addIffs;
  2086 
  2087   3) a tactic for record field splitting (record_split_tac) is part of
  2088 the standard claset (addSWrapper);
  2089 
  2090 To get a better idea about these rules you may retrieve them via
  2091 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2092 the name of your record type.
  2093 
  2094 The split tactic 3) conceptually simplifies by the following rule:
  2095 
  2096   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2097 
  2098 Thus any record variable that is bound by meta-all will automatically
  2099 blow up into some record constructor term, consequently the
  2100 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2101 solve record problems automatically.
  2102 
  2103 
  2104 * reorganized the main HOL image: HOL/Integ and String loaded by
  2105 default; theory Main includes everything;
  2106 
  2107 * automatic simplification of integer sums and comparisons, using cancellation;
  2108 
  2109 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2110 
  2111 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2112 
  2113 * many new identities for unions, intersections, set difference, etc.;
  2114 
  2115 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2116 called split_if, split_split, split_sum_case and split_nat_case (to go
  2117 with add/delsplits);
  2118 
  2119 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2120 (?x::unit) = (); this is made part of the default simpset, which COULD
  2121 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2122 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2123 unit_abs_eta_conv is added in order to counter the effect of
  2124 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2125 %u.f();
  2126 
  2127 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2128 makes more sense);
  2129 
  2130 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2131   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2132   disjointness reasoning but breaking a few old proofs.
  2133 
  2134 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2135 to 'converse' from 'inverse' (for compatibility with ZF and some
  2136 literature);
  2137 
  2138 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2139 the well-founded relation;
  2140 
  2141 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2142     Compl A.  The "Compl" syntax remains available as input syntax for this
  2143     release ONLY.
  2144 
  2145 * HOL/Update: new theory of function updates:
  2146     f(a:=b) == %x. if x=a then b else f x
  2147 may also be iterated as in f(a:=b,c:=d,...);
  2148 
  2149 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2150 
  2151 * HOL/List:
  2152   - new function list_update written xs[i:=v] that updates the i-th
  2153     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2154   - new function `upt' written [i..j(] which generates the list
  2155     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2156     bound write [i..j], which is a shorthand for [i..j+1(].
  2157   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2158 
  2159 * HOL/Arith:
  2160   - removed 'pred' (predecessor) function;
  2161   - generalized some theorems about n-1;
  2162   - many new laws about "div" and "mod";
  2163   - new laws about greatest common divisors (see theory ex/Primes);
  2164 
  2165 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2166 instead of "inverse";
  2167 
  2168 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2169   of the multiset ordering;
  2170 
  2171 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2172   (not included by default);
  2173 
  2174 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2175 
  2176 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2177   programs, i.e. different program variables may have different types.
  2178 
  2179 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2180   [previously, this check worked only if the rewrite rule was unconditional]
  2181   Now rew can involve either definitions or equalities (either == or =).
  2182 
  2183 
  2184 *** ZF ***
  2185 
  2186 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2187   only the theorems proved on ZF.ML;
  2188 
  2189 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2190   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2191   disjointness reasoning but breaking a few old proofs.
  2192 
  2193 * ZF/Update: new theory of function updates
  2194     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2195   may also be iterated as in f(a:=b,c:=d,...);
  2196 
  2197 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2198 
  2199 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2200   [previously, this check worked only if the rewrite rule was unconditional]
  2201   Now rew can involve either definitions or equalities (either == or =).
  2202 
  2203 * case_tac provided for compatibility with HOL
  2204     (like the old excluded_middle_tac, but with subgoals swapped)
  2205 
  2206 
  2207 *** Internal programming interfaces ***
  2208 
  2209 * Pure: several new basic modules made available for general use, see
  2210 also src/Pure/README;
  2211 
  2212 * improved the theory data mechanism to support encapsulation (data
  2213 kind name replaced by private Object.kind, acting as authorization
  2214 key); new type-safe user interface via functor TheoryDataFun; generic
  2215 print_data function becomes basically useless;
  2216 
  2217 * removed global_names compatibility flag -- all theory declarations
  2218 are qualified by default;
  2219 
  2220 * module Pure/Syntax now offers quote / antiquote translation
  2221 functions (useful for Hoare logic etc. with implicit dependencies);
  2222 see HOL/ex/Antiquote for an example use;
  2223 
  2224 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2225 cterm -> thm;
  2226 
  2227 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2228 subgoal;
  2229 
  2230 * Display.print_goals function moved to Locale.print_goals;
  2231 
  2232 * standard print function for goals supports current_goals_markers
  2233 variable for marking begin of proof, end of proof, start of goal; the
  2234 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2235 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2236 for example;
  2237 
  2238 
  2239 
  2240 New in Isabelle98 (January 1998)
  2241 --------------------------------
  2242 
  2243 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2244 
  2245 * changed lexical syntax of terms / types: dots made part of long
  2246 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2247 
  2248 * simpset (and claset) reference variable replaced by functions
  2249 simpset / simpset_ref;
  2250 
  2251 * no longer supports theory aliases (via merge) and non-trivial
  2252 implicit merge of thms' signatures;
  2253 
  2254 * most internal names of constants changed due to qualified names;
  2255 
  2256 * changed Pure/Sequence interface (see Pure/seq.ML);
  2257 
  2258 
  2259 *** General Changes ***
  2260 
  2261 * hierachically structured name spaces (for consts, types, axms, thms
  2262 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2263 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2264 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2265 long_names for fully qualified output names; NOTE: ML programs
  2266 (special tactics, packages etc.) referring to internal names may have
  2267 to be adapted to cope with fully qualified names; in case of severe
  2268 backward campatibility problems try setting 'global_names' at compile
  2269 time to have enrything declared within a flat name space; one may also
  2270 fine tune name declarations in theories via the 'global' and 'local'
  2271 section;
  2272 
  2273 * reimplemented the implicit simpset and claset using the new anytype
  2274 data filed in signatures; references simpset:simpset ref etc. are
  2275 replaced by functions simpset:unit->simpset and
  2276 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2277 to patch your ML files accordingly;
  2278 
  2279 * HTML output now includes theory graph data for display with Java
  2280 applet or isatool browser; data generated automatically via isatool
  2281 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2282 
  2283 * defs may now be conditional; improved rewrite_goals_tac to handle
  2284 conditional equations;
  2285 
  2286 * defs now admits additional type arguments, using TYPE('a) syntax;
  2287 
  2288 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2289 creates a new theory node; implicit merge of thms' signatures is
  2290 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2291 transfer:theory->thm->thm in (rare) cases;
  2292 
  2293 * improved handling of draft signatures / theories; draft thms (and
  2294 ctyps, cterms) are automatically promoted to real ones;
  2295 
  2296 * slightly changed interfaces for oracles: admit many per theory, named
  2297 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2298 
  2299 * print_goals: optional output of const types (set show_consts and
  2300 show_types);
  2301 
  2302 * improved output of warnings (###) and errors (***);
  2303 
  2304 * subgoal_tac displays a warning if the new subgoal has type variables;
  2305 
  2306 * removed old README and Makefiles;
  2307 
  2308 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2309 
  2310 * removed obsolete init_pps and init_database;
  2311 
  2312 * deleted the obsolete tactical STATE, which was declared by
  2313     fun STATE tacfun st = tacfun st st;
  2314 
  2315 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2316 (which abbreviates $HOME);
  2317 
  2318 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2319 use isatool fixseq to adapt your ML programs (this works for fully
  2320 qualified references to the Sequence structure only!);
  2321 
  2322 * use_thy no longer requires writable current directory; it always
  2323 reloads .ML *and* .thy file, if either one is out of date;
  2324 
  2325 
  2326 *** Classical Reasoner ***
  2327 
  2328 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2329 tactics that use classical reasoning to simplify a subgoal without
  2330 splitting it into several subgoals;
  2331 
  2332 * Safe_tac: like safe_tac but uses the default claset;
  2333 
  2334 
  2335 *** Simplifier ***
  2336 
  2337 * added simplification meta rules:
  2338     (asm_)(full_)simplify: simpset -> thm -> thm;
  2339 
  2340 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2341 logics (again);
  2342 
  2343 * added prems argument to simplification procedures;
  2344 
  2345 * HOL, FOL, ZF: added infix function `addsplits':
  2346   instead of `<simpset> setloop (split_tac <thms>)'
  2347   you can simply write `<simpset> addsplits <thms>'
  2348 
  2349 
  2350 *** Syntax ***
  2351 
  2352 * TYPE('a) syntax for type reflection terms;
  2353 
  2354 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2355 
  2356 * pretty printer: changed order of mixfix annotation preference (again!);
  2357 
  2358 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2359 
  2360 
  2361 *** HOL ***
  2362 
  2363 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2364   with `addloop' of the simplifier to faciliate case splitting in premises.
  2365 
  2366 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2367 
  2368 * HOL/Auth: new protocol proofs including some for the Internet
  2369   protocol TLS;
  2370 
  2371 * HOL/Map: new theory of `maps' a la VDM;
  2372 
  2373 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2374 cancelling out common nat summands from =, <, <= (in)equalities, or
  2375 differences; simplification procedures nat_cancel_factor for
  2376 cancelling common factor from =, <, <= (in)equalities over natural
  2377 sums; nat_cancel contains both kinds of procedures, it is installed by
  2378 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2379 
  2380 * HOL/simplifier: terms of the form
  2381   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2382   are rewritten to
  2383   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2384   and those of the form
  2385   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2386   are rewritten to
  2387   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2388 
  2389 * HOL/datatype
  2390   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2391 
  2392   P(t_case f1 ... fn x) =
  2393      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2394         ...
  2395        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2396      )
  2397 
  2398   and a theorem `split_t_case_asm' of the form
  2399 
  2400   P(t_case f1 ... fn x) =
  2401     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2402         ...
  2403        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2404      )
  2405   which can be added to a simpset via `addsplits'. The existing theorems
  2406   expand_list_case and expand_option_case have been renamed to
  2407   split_list_case and split_option_case.
  2408 
  2409 * HOL/Arithmetic:
  2410   - `pred n' is automatically converted to `n-1'.
  2411     Users are strongly encouraged not to use `pred' any longer,
  2412     because it will disappear altogether at some point.
  2413   - Users are strongly encouraged to write "0 < n" rather than
  2414     "n ~= 0". Theorems and proof tools have been modified towards this
  2415     `standard'.
  2416 
  2417 * HOL/Lists:
  2418   the function "set_of_list" has been renamed "set" (and its theorems too);
  2419   the function "nth" now takes its arguments in the reverse order and
  2420   has acquired the infix notation "!" as in "xs!n".
  2421 
  2422 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2423 
  2424 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2425   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2426 
  2427 * HOL/record: extensible records with schematic structural subtyping
  2428 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2429 still lacks various theorems and concrete record syntax;
  2430 
  2431 
  2432 *** HOLCF ***
  2433 
  2434 * removed "axioms" and "generated by" sections;
  2435 
  2436 * replaced "ops" section by extended "consts" section, which is capable of
  2437   handling the continuous function space "->" directly;
  2438 
  2439 * domain package:
  2440   . proves theorems immediately and stores them in the theory,
  2441   . creates hierachical name space,
  2442   . now uses normal mixfix annotations (instead of cinfix...),
  2443   . minor changes to some names and values (for consistency),
  2444   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2445   . separator between mutual domain defs: changed "," to "and",
  2446   . improved handling of sort constraints;  now they have to
  2447     appear on the left-hand side of the equations only;
  2448 
  2449 * fixed LAM <x,y,zs>.b syntax;
  2450 
  2451 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2452 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2453 
  2454 
  2455 *** FOL and ZF ***
  2456 
  2457 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2458   with `addloop' of the simplifier to faciliate case splitting in premises.
  2459 
  2460 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2461 in HOL, they strip ALL and --> from proved theorems;
  2462 
  2463 
  2464 
  2465 New in Isabelle94-8 (May 1997)
  2466 ------------------------------
  2467 
  2468 *** General Changes ***
  2469 
  2470 * new utilities to build / run / maintain Isabelle etc. (in parts
  2471 still somewhat experimental); old Makefiles etc. still functional;
  2472 
  2473 * new 'Isabelle System Manual';
  2474 
  2475 * INSTALL text, together with ./configure and ./build scripts;
  2476 
  2477 * reimplemented type inference for greater efficiency, better error
  2478 messages and clean internal interface;
  2479 
  2480 * prlim command for dealing with lots of subgoals (an easier way of
  2481 setting goals_limit);
  2482 
  2483 
  2484 *** Syntax ***
  2485 
  2486 * supports alternative (named) syntax tables (parser and pretty
  2487 printer); internal interface is provided by add_modesyntax(_i);
  2488 
  2489 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2490 be used in conjunction with the Isabelle symbol font; uses the
  2491 "symbols" syntax table;
  2492 
  2493 * added token_translation interface (may translate name tokens in
  2494 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2495 the current print_mode); IMPORTANT: user print translation functions
  2496 are responsible for marking newly introduced bounds
  2497 (Syntax.mark_boundT);
  2498 
  2499 * token translations for modes "xterm" and "xterm_color" that display
  2500 names in bold, underline etc. or colors (which requires a color
  2501 version of xterm);
  2502 
  2503 * infixes may now be declared with names independent of their syntax;
  2504 
  2505 * added typed_print_translation (like print_translation, but may
  2506 access type of constant);
  2507 
  2508 
  2509 *** Classical Reasoner ***
  2510 
  2511 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2512 some limitations.  Blast_tac...
  2513   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2514   + ignores elimination rules that don't have the correct format
  2515         (the conclusion MUST be a formula variable)
  2516   + ignores types, which can make HOL proofs fail
  2517   + rules must not require higher-order unification, e.g. apply_type in ZF
  2518     [message "Function Var's argument not a bound variable" relates to this]
  2519   + its proof strategy is more general but can actually be slower
  2520 
  2521 * substitution with equality assumptions no longer permutes other
  2522 assumptions;
  2523 
  2524 * minor changes in semantics of addafter (now called addaltern); renamed
  2525 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2526 (and access functions for it);
  2527 
  2528 * improved combination of classical reasoner and simplifier:
  2529   + functions for handling clasimpsets
  2530   + improvement of addss: now the simplifier is called _after_ the
  2531     safe steps.
  2532   + safe variant of addss called addSss: uses safe simplifications
  2533     _during_ the safe steps. It is more complete as it allows multiple
  2534     instantiations of unknowns (e.g. with slow_tac).
  2535 
  2536 *** Simplifier ***
  2537 
  2538 * added interface for simplification procedures (functions that
  2539 produce *proven* rewrite rules on the fly, depending on current
  2540 redex);
  2541 
  2542 * ordering on terms as parameter (used for ordered rewriting);
  2543 
  2544 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2545 
  2546 * the solver is now split into a safe and an unsafe part.
  2547 This should be invisible for the normal user, except that the
  2548 functions setsolver and addsolver have been renamed to setSolver and
  2549 addSolver; added safe_asm_full_simp_tac;
  2550 
  2551 
  2552 *** HOL ***
  2553 
  2554 * a generic induction tactic `induct_tac' which works for all datatypes and
  2555 also for type `nat';
  2556 
  2557 * a generic case distinction tactic `exhaust_tac' which works for all
  2558 datatypes and also for type `nat';
  2559 
  2560 * each datatype comes with a function `size';
  2561 
  2562 * patterns in case expressions allow tuple patterns as arguments to
  2563 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2564 
  2565 * primrec now also works with type nat;
  2566 
  2567 * recdef: a new declaration form, allows general recursive functions to be
  2568 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2569 
  2570 * the constant for negation has been renamed from "not" to "Not" to
  2571 harmonize with FOL, ZF, LK, etc.;
  2572 
  2573 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2574 infinite lists;
  2575 
  2576 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2577 
  2578 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2579 problems in commutative rings, using axiomatic type classes for + and *;
  2580 
  2581 * more examples in HOL/MiniML and HOL/Auth;
  2582 
  2583 * more default rewrite rules for quantifiers, union/intersection;
  2584 
  2585 * a new constant `arbitrary == @x.False';
  2586 
  2587 * HOLCF/IOA replaces old HOL/IOA;
  2588 
  2589 * HOLCF changes: derived all rules and arities
  2590   + axiomatic type classes instead of classes
  2591   + typedef instead of faking type definitions
  2592   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2593   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2594   + eliminated the types void, one, tr
  2595   + use unit lift and bool lift (with translations) instead of one and tr
  2596   + eliminated blift from Lift3.thy (use Def instead of blift)
  2597   all eliminated rules are derived as theorems --> no visible changes ;
  2598 
  2599 
  2600 *** ZF ***
  2601 
  2602 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2603 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2604 as ZF_cs addSIs [equalityI];
  2605 
  2606 
  2607 
  2608 New in Isabelle94-7 (November 96)
  2609 ---------------------------------
  2610 
  2611 * allowing negative levels (as offsets) in prlev and choplev;
  2612 
  2613 * super-linear speedup for large simplifications;
  2614 
  2615 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2616 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2617 FAIL); can suppress it using the command Delsimps (ex_simps @
  2618 all_simps); De Morgan laws are also now included, by default;
  2619 
  2620 * improved printing of ==>  :  ~:
  2621 
  2622 * new object-logic "Sequents" adds linear logic, while replacing LK
  2623 and Modal (thanks to Sara Kalvala);
  2624 
  2625 * HOL/Auth: correctness proofs for authentication protocols;
  2626 
  2627 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2628 examples on HOL/Auth);
  2629 
  2630 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2631 the rewriter and classical reasoner simultaneously;
  2632 
  2633 * function uresult no longer returns theorems in "standard" format;
  2634 regain previous version by: val uresult = standard o uresult;
  2635 
  2636 
  2637 
  2638 New in Isabelle94-6
  2639 -------------------
  2640 
  2641 * oracles -- these establish an interface between Isabelle and trusted
  2642 external reasoners, which may deliver results as theorems;
  2643 
  2644 * proof objects (in particular record all uses of oracles);
  2645 
  2646 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2647 
  2648 * "constdefs" section in theory files;
  2649 
  2650 * "primrec" section (HOL) no longer requires names;
  2651 
  2652 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2653 
  2654 
  2655 
  2656 New in Isabelle94-5
  2657 -------------------
  2658 
  2659 * reduced space requirements;
  2660 
  2661 * automatic HTML generation from theories;
  2662 
  2663 * theory files no longer require "..." (quotes) around most types;
  2664 
  2665 * new examples, including two proofs of the Church-Rosser theorem;
  2666 
  2667 * non-curried (1994) version of HOL is no longer distributed;
  2668 
  2669 
  2670 
  2671 New in Isabelle94-4
  2672 -------------------
  2673 
  2674 * greatly reduced space requirements;
  2675 
  2676 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2677 
  2678 * searchable theorem database (see the section "Retrieving theorems" on
  2679 page 8 of the Reference Manual);
  2680 
  2681 * new examples, including Grabczewski's monumental case study of the
  2682 Axiom of Choice;
  2683 
  2684 * The previous version of HOL renamed to Old_HOL;
  2685 
  2686 * The new version of HOL (previously called CHOL) uses a curried syntax
  2687 for functions.  Application looks like f a b instead of f(a,b);
  2688 
  2689 * Mutually recursive inductive definitions finally work in HOL;
  2690 
  2691 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2692 translates to the operator "split";
  2693 
  2694 
  2695 
  2696 New in Isabelle94-3
  2697 -------------------
  2698 
  2699 * new infix operator, addss, allowing the classical reasoner to
  2700 perform simplification at each step of its search.  Example:
  2701         fast_tac (cs addss ss)
  2702 
  2703 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2704 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2705 look like (a,b) instead of <a,b>;
  2706 
  2707 * PLEASE NOTE: CHOL will eventually replace HOL!
  2708 
  2709 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2710 It translates to the operator "split".  A new theory of integers is available;
  2711 
  2712 * In ZF, integer numerals now denote two's-complement binary integers.
  2713 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2714 
  2715 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2716 of the Axiom of Choice;
  2717 
  2718 
  2719 
  2720 New in Isabelle94-2
  2721 -------------------
  2722 
  2723 * Significantly faster resolution;
  2724 
  2725 * the different sections in a .thy file can now be mixed and repeated
  2726 freely;
  2727 
  2728 * Database of theorems for FOL, HOL and ZF.  New
  2729 commands including qed, qed_goal and bind_thm store theorems in the database.
  2730 
  2731 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2732 a given theory (thms_of), or find out what theory a theorem was proved in
  2733 (theory_of_thm);
  2734 
  2735 * Bugs fixed in the inductive definition and datatype packages;
  2736 
  2737 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2738 and HOL_dup_cs obsolete;
  2739 
  2740 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2741 have been removed;
  2742 
  2743 * Simpler definition of function space in ZF;
  2744 
  2745 * new results about cardinal and ordinal arithmetic in ZF;
  2746 
  2747 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2748 types;
  2749 
  2750 
  2751 $Id$