NEWS
author wenzelm
Sun Jun 20 09:26:29 2004 +0200 (2004-06-20)
changeset 14972 51f95648abad
parent 14934 bf9f525d4821
child 15011 35be762f58f9
permissions -rw-r--r--
tuned;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Pure: considerably improved version of 'constdefs' command.  Now
    10   performs automatic type-inference of declared constants; additional
    11   support for local structure declarations (cf. locales and HOL
    12   records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    13   to observe strictly sequential dependencies of definitions within a
    14   single 'constdefs' section; moreover, the declared name needs to be
    15   an identifier.  If all fails, consider to fall back on 'consts' and
    16   'defs' separately.
    17 
    18 * Pure: improved indexed syntax and implicit structures.  First of
    19   all, indexed syntax provides a notational device for subscripted
    20   application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    21   expressions.  Secondly, in a local context with structure
    22   declarations, number indexes \<^sub>n or the empty index (default
    23   number 1) refer to a certain fixed variable implicitly; option
    24   show_structs controls printing of implicit structures.  Typical
    25   applications of these concepts involve record types and locales.
    26 
    27 * Pure: clear separation of logical types and nonterminals, where the
    28   latter may only occur in 'syntax' specifications or type
    29   abbreviations.  Before that distinction was only partially
    30   implemented via type class "logic" vs. "{}".  Potential
    31   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
    32   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
    33   specifications may require further adaption (e.g. Cube/Base.thy).
    34 
    35 * Pure: removed obsolete type class "logic", use the top sort {}
    36   instead.  Note that non-logical types should be declared as
    37   'nonterminals' rather than 'types'.  INCOMPATIBILITY for new
    38   object-logic specifications.
    39 
    40 * Pure/Syntax: inner syntax includes (*(*nested*) comments*).
    41 
    42 * Pure/Syntax: pretty pinter now supports unbreakable blocks,
    43   specified in mixfix annotations as "(00...)".
    44 
    45 * Pure/Syntax: 'advanced' translation functions (parse_translation
    46   etc.) may depend on the signature of the theory context being
    47   presently used for parsing/printing, see also isar-ref manual.
    48 
    49 * Pure: tuned internal renaming of symbolic identifiers -- attach
    50   primes instead of base 26 numbers.
    51 
    52 * Document preparation: antiquotations now provide the option
    53   'locale=NAME' to specify an alternative context used for evaluating
    54   and printing the subsequent argument, as in @{thm [locale=LC]
    55   fold_commute}, for example.
    56 
    57 * Document preparation: commands 'display_drafts' and 'print_drafts'
    58   perform simple output of raw sources.  Only those symbols that do
    59   not require additional LaTeX packages (depending on comments in
    60   isabellesym.sty) are displayed properly, everything else is left
    61   verbatim.  We use isatool display and isatool print as front ends;
    62   these are subject to the DVI_VIEWER and PRINT_COMMAND settings,
    63   respectively.
    64 
    65 * ML: output via the Isabelle channels of writeln/warning/error
    66   etc. is now passed through Output.output, with a hook for arbitrary
    67   transformations depending on the print_mode (cf. Output.add_mode --
    68   the first active mode that provides a output function wins).
    69   Already formatted output may be embedded into further text via
    70   Output.raw; the result of Pretty.string_of/str_of and derived
    71   functions (string_of_term/cterm/thm etc.) is already marked raw to
    72   accommodate easy composition of diagnostic messages etc.
    73   Programmers rarely need to care about Output.output or Output.raw at
    74   all, with some notable exceptions: Output.output is required when
    75   bypassing the standard channels (writeln etc.), or in token
    76   translations to produce properly formatted results; Output.raw is
    77   required when capturing already output material that will eventually
    78   be presented to the user a second time.  For the default print mode,
    79   both Output.output and Output.raw have no effect.
    80 
    81 
    82 *** HOL ***
    83 
    84 * HOL/record: reimplementation of records. Improved scalability for
    85   records with many fields, avoiding performance problems for type
    86   inference. Records are no longer composed of nested field types, but
    87   of nested extension types. Therefore the record type only grows
    88   linear in the number of extensions and not in the number of fields.
    89   The top-level (users) view on records is preserved.  Potential
    90   INCOMPATIBILITY only in strange cases, where the theory depends on
    91   the old record representation. The type generated for a record is
    92   called <record_name>_ext_type.
    93 
    94 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
    95 
    96   syntax (epsilon)
    97     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
    98 
    99   The symbol \<some> is displayed as the alternative epsilon of LaTeX
   100   and x-symbol; use option '-m epsilon' to get it actually printed.
   101   Moreover, the mathematically important symbolic identifier
   102   \<epsilon> becomes available as variable, constant etc.
   103 
   104 * Simplifier: "record_upd_simproc" for simplification of multiple
   105   record updates enabled by default.  INCOMPATIBILITY: old proofs
   106   break occasionally, since simplification is more powerful by
   107   default.
   108 
   109 
   110 *** HOLCF ***
   111 
   112 * HOLCF: discontinued special version of 'constdefs' (which used to
   113   support continuous functions) in favor of the general Pure one with
   114   full type-inference.
   115 
   116 
   117 *** ZF ***
   118 
   119 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the First
   120   Isomorphism Theorem (on quotienting by the kernel of a homomorphism).
   121 
   122 
   123 
   124 New in Isabelle2004 (April 2004)
   125 --------------------------------
   126 
   127 *** General ***
   128 
   129 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   130   Replaces linorder.ML.
   131 
   132 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   133   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   134   (\<a>...\<z>), are now considered normal letters, and can therefore
   135   be used anywhere where an ASCII letter (a...zA...Z) has until
   136   now. COMPATIBILITY: This obviously changes the parsing of some
   137   terms, especially where a symbol has been used as a binder, say
   138   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   139   as an identifier.  Fix it by inserting a space around former
   140   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   141   existing theory and ML files.
   142 
   143 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   144 
   145 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   146   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   147   a normal (but invisible) letter. For multiple letter subscripts repeat
   148   \<^isub> like this: x\<^isub>1\<^isub>2.
   149 
   150 * Pure: There are now sub-/superscripts that can span more than one
   151   character. Text between \<^bsub> and \<^esub> is set in subscript in
   152   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   153   superscript. The new control characters are not identifier parts.
   154 
   155 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   156   content of "..." to the latex file instead of \isacntrl... . The "..."
   157   may consist of any printable characters excluding the end bracket >.
   158 
   159 * Pure: Using new Isar command "finalconsts" (or the ML functions
   160   Theory.add_finals or Theory.add_finals_i) it is now possible to
   161   declare constants "final", which prevents their being given a definition
   162   later.  It is useful for constants whose behaviour is fixed axiomatically
   163   rather than definitionally, such as the meta-logic connectives.
   164 
   165 * Pure: 'instance' now handles general arities with general sorts
   166   (i.e. intersections of classes),
   167 
   168 * Presentation: generated HTML now uses a CSS style sheet to make layout
   169   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   170   It can be changed to alter the colors/layout of generated pages.
   171 
   172 
   173 *** Isar ***
   174 
   175 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   176   cut_tac, subgoal_tac and thin_tac:
   177   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   178     locales are no longer forced to write Isar proof scripts.
   179     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   180     emulations.
   181   - INCOMPATIBILITY: names of variables to be instantiated may no
   182     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   183     This is consistent with the instantiation attribute "where".
   184 
   185 * Attributes "where" and "of":
   186   - Now take type variables of instantiated theorem into account when reading
   187     the instantiation string.  This fixes a bug that caused instantiated
   188     theorems to have too special types in some circumstances.
   189   - "where" permits explicit instantiations of type variables.
   190 
   191 * Calculation commands "moreover" and "also" no longer interfere with
   192   current facts ("this"), admitting arbitrary combinations with "then"
   193   and derived forms.
   194 
   195 * Locales:
   196   - Goal statements involving the context element "includes" no longer
   197     generate theorems with internal delta predicates (those ending on
   198     "_axioms") in the premise.
   199     Resolve particular premise with <locale>.intro to obtain old form.
   200   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   201     specification and "includes" elements in goal statement.
   202   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   203     [intro?] and [elim?] (respectively) by default.
   204   - Experimental command for instantiation of locales in proof contexts:
   205         instantiate <label>[<attrs>]: <loc>
   206     Instantiates locale <loc> and adds all its theorems to the current context
   207     taking into account their attributes.  Label and attrs are optional
   208     modifiers, like in theorem declarations.  If present, names of
   209     instantiated theorems are qualified with <label>, and the attributes
   210     <attrs> are applied after any attributes these theorems might have already.
   211       If the locale has assumptions, a chained fact of the form
   212     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   213     are derived.  The command does not support old-style locales declared
   214     with "locale (open)".
   215       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   216 
   217 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   218   (Isar) contexts.
   219 
   220 
   221 *** HOL ***
   222 
   223 * Proof import: new image HOL4 contains the imported library from
   224   the HOL4 system with about 2500 theorems. It is imported by
   225   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   226   can be used like any other Isabelle image.  See
   227   HOL/Import/HOL/README for more information.
   228 
   229 * Simplifier:
   230   - Much improved handling of linear and partial orders.
   231     Reasoners for linear and partial orders are set up for type classes
   232     "linorder" and "order" respectively, and are added to the default simpset
   233     as solvers.  This means that the simplifier can build transitivity chains
   234     to solve goals from the assumptions.
   235   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   236     of blast or auto after simplification become unnecessary because the goal
   237     is solved by simplification already.
   238 
   239 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   240     all proved in axiomatic type classes for semirings, rings and fields.
   241 
   242 * Numerics:
   243   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   244     now formalized using the Ring_and_Field theory mentioned above.
   245   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   246     than before, because now they are set up once in a generic manner.
   247   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   248     Look for the general versions in Ring_and_Field (and Power if they concern
   249     exponentiation).
   250 
   251 * Type "rat" of the rational numbers is now available in HOL-Complex.
   252 
   253 * Records:
   254   - Record types are now by default printed with their type abbreviation
   255     instead of the list of all field types. This can be configured via
   256     the reference "print_record_type_abbr".
   257   - Simproc "record_upd_simproc" for simplification of multiple updates added
   258     (not enabled by default).
   259   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   260     EX x. x = sel r to True (not enabled by default).
   261   - Tactic "record_split_simp_tac" to split and simplify records added.
   262 
   263 * 'specification' command added, allowing for definition by
   264   specification.  There is also an 'ax_specification' command that
   265   introduces the new constants axiomatically.
   266 
   267 * arith(_tac) is now able to generate counterexamples for reals as well.
   268 
   269 * HOL-Algebra: new locale "ring" for non-commutative rings.
   270 
   271 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   272   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   273 
   274 * HOL-Matrix: a first theory for matrices in HOL with an application of
   275   matrix theory to linear programming.
   276 
   277 * Unions and Intersections:
   278   The x-symbol output syntax of UN and INT has been changed
   279   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   280   i.e. the index formulae has become a subscript, like in normal math.
   281   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   282   The subscript version is also accepted as input syntax.
   283 
   284 * Unions and Intersections over Intervals:
   285   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   286   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   287   like in normal math, and corresponding versions for < and for intersection.
   288 
   289 * ML: the legacy theory structures Int and List have been removed. They had
   290   conflicted with ML Basis Library structures having the same names.
   291 
   292 * 'refute' command added to search for (finite) countermodels.  Only works
   293   for a fragment of HOL.  The installation of an external SAT solver is
   294   highly recommended.  See "HOL/Refute.thy" for details.
   295 
   296 * 'quickcheck' command: Allows to find counterexamples by evaluating
   297   formulae under an assignment of free variables to random values.
   298   In contrast to 'refute', it can deal with inductive datatypes,
   299   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   300   for examples.
   301 
   302 
   303 *** HOLCF ***
   304 
   305 * Streams now come with concatenation and are part of the HOLCF image
   306 
   307 
   308 
   309 New in Isabelle2003 (May 2003)
   310 ------------------------------
   311 
   312 *** General ***
   313 
   314 * Provers/simplifier:
   315 
   316   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   317     Assumptions are now subject to complete mutual simplification,
   318     not just from left to right. The simplifier now preserves
   319     the order of assumptions.
   320 
   321     Potential INCOMPATIBILITY:
   322 
   323     -- simp sometimes diverges where the old version did
   324        not, e.g. invoking simp on the goal
   325 
   326         [| P (f x); y = x; f x = f y |] ==> Q
   327 
   328        now gives rise to the infinite reduction sequence
   329 
   330         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   331 
   332        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   333        kind of problem.
   334 
   335     -- Tactics combining classical reasoner and simplification (such as auto)
   336        are also affected by this change, because many of them rely on
   337        simp. They may sometimes diverge as well or yield a different numbers
   338        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   339        in case of problems. Sometimes subsequent calls to the classical
   340        reasoner will fail because a preceeding call to the simplifier too
   341        eagerly simplified the goal, e.g. deleted redundant premises.
   342 
   343   - The simplifier trace now shows the names of the applied rewrite rules
   344 
   345   - You can limit the number of recursive invocations of the simplifier
   346     during conditional rewriting (where the simplifie tries to solve the
   347     conditions before applying the rewrite rule):
   348     ML "simp_depth_limit := n"
   349     where n is an integer. Thus you can force termination where previously
   350     the simplifier would diverge.
   351 
   352   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   353 
   354   - No longer aborts on failed congruence proof.  Instead, the
   355     congruence is ignored.
   356 
   357 * Pure: New generic framework for extracting programs from constructive
   358   proofs. See HOL/Extraction.thy for an example instantiation, as well
   359   as HOL/Extraction for some case studies.
   360 
   361 * Pure: The main goal of the proof state is no longer shown by default, only
   362 the subgoals. This behaviour is controlled by a new flag.
   363    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   364 (ML: Proof.show_main_goal).
   365 
   366 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   367 rules whose conclusion matches subgoal 1:
   368       PG menu: Isabelle/Isar -> Show me -> matching rules
   369 The rules are ordered by how closely they match the subgoal.
   370 In particular, rules that solve a subgoal outright are displayed first
   371 (or rather last, the way they are printed).
   372 (ML: ProofGeneral.print_intros())
   373 
   374 * Pure: New flag trace_unify_fail causes unification to print
   375 diagnostic information (PG: in trace buffer) when it fails. This is
   376 useful for figuring out why single step proofs like rule, erule or
   377 assumption failed.
   378 
   379 * Pure: Locale specifications now produce predicate definitions
   380 according to the body of text (covering assumptions modulo local
   381 definitions); predicate "loc_axioms" covers newly introduced text,
   382 while "loc" is cumulative wrt. all included locale expressions; the
   383 latter view is presented only on export into the global theory
   384 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   385 on the old view without predicates;
   386 
   387 * Pure: predefined locales "var" and "struct" are useful for sharing
   388 parameters (as in CASL, for example); just specify something like
   389 ``var x + var y + struct M'' as import;
   390 
   391 * Pure: improved thms_containing: proper indexing of facts instead of
   392 raw theorems; check validity of results wrt. current name space;
   393 include local facts of proof configuration (also covers active
   394 locales), cover fixed variables in index; may use "_" in term
   395 specification; an optional limit for the number of printed facts may
   396 be given (the default is 40);
   397 
   398 * Pure: disallow duplicate fact bindings within new-style theory files
   399 (batch-mode only);
   400 
   401 * Provers: improved induct method: assumptions introduced by case
   402 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   403 the goal statement); "foo" still refers to all facts collectively;
   404 
   405 * Provers: the function blast.overloaded has been removed: all constants
   406 are regarded as potentially overloaded, which improves robustness in exchange
   407 for slight decrease in efficiency;
   408 
   409 * Provers/linorder: New generic prover for transitivity reasoning over
   410 linear orders.  Note: this prover is not efficient!
   411 
   412 * Isar: preview of problems to finish 'show' now produce an error
   413 rather than just a warning (in interactive mode);
   414 
   415 
   416 *** HOL ***
   417 
   418 * arith(_tac)
   419 
   420  - Produces a counter example if it cannot prove a goal.
   421    Note that the counter example may be spurious if the goal is not a formula
   422    of quantifier-free linear arithmetic.
   423    In ProofGeneral the counter example appears in the trace buffer.
   424 
   425  - Knows about div k and mod k where k is a numeral of type nat or int.
   426 
   427  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   428    linear arithmetic fails. This takes account of quantifiers and divisibility.
   429    Presburger arithmetic can also be called explicitly via presburger(_tac).
   430 
   431 * simp's arithmetic capabilities have been enhanced a bit: it now
   432 takes ~= in premises into account (by performing a case split);
   433 
   434 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   435 are distributed over a sum of terms;
   436 
   437 * New tactic "trans_tac" and method "trans" instantiate
   438 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   439 "<=", "<" and "=").
   440 
   441 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   442 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   443 
   444 * 'typedef' command has new option "open" to suppress the set
   445 definition;
   446 
   447 * functions Min and Max on finite sets have been introduced (theory
   448 Finite_Set);
   449 
   450 * attribute [symmetric] now works for relations as well; it turns
   451 (x,y) : R^-1 into (y,x) : R, and vice versa;
   452 
   453 * induct over a !!-quantified statement (say !!x1..xn):
   454   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   455 
   456 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   457 %x. None. Warning: empty_def now refers to the previously hidden definition
   458 of the empty set.
   459 
   460 * Algebra: formalization of classical algebra.  Intended as base for
   461 any algebraic development in Isabelle.  Currently covers group theory
   462 (up to Sylow's theorem) and ring theory (Universal Property of
   463 Univariate Polynomials).  Contributions welcome;
   464 
   465 * GroupTheory: deleted, since its material has been moved to Algebra;
   466 
   467 * Complex: new directory of the complex numbers with numeric constants,
   468 nonstandard complex numbers, and some complex analysis, standard and
   469 nonstandard (Jacques Fleuriot);
   470 
   471 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   472 
   473 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   474 Fleuriot);
   475 
   476 * Real/HahnBanach: updated and adapted to locales;
   477 
   478 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   479 Gray and Kramer);
   480 
   481 * UNITY: added the Meier-Sanders theory of progress sets;
   482 
   483 * MicroJava: bytecode verifier and lightweight bytecode verifier
   484 as abstract algorithms, instantiated to the JVM;
   485 
   486 * Bali: Java source language formalization. Type system, operational
   487 semantics, axiomatic semantics. Supported language features:
   488 classes, interfaces, objects,virtual methods, static methods,
   489 static/instance fields, arrays, access modifiers, definite
   490 assignment, exceptions.
   491 
   492 
   493 *** ZF ***
   494 
   495 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   496 universe, etc.);
   497 
   498 * Main ZF: virtually all theories converted to new-style format;
   499 
   500 
   501 *** ML ***
   502 
   503 * Pure: Tactic.prove provides sane interface for internal proofs;
   504 omits the infamous "standard" operation, so this is more appropriate
   505 than prove_goalw_cterm in many situations (e.g. in simprocs);
   506 
   507 * Pure: improved error reporting of simprocs;
   508 
   509 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   510 up simprocs;
   511 
   512 
   513 *** Document preparation ***
   514 
   515 * uses \par instead of \\ for line breaks in theory text. This may
   516 shift some page breaks in large documents. To get the old behaviour
   517 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   518 
   519 * minimized dependencies of isabelle.sty and isabellesym.sty on
   520 other packages
   521 
   522 * \<euro> now needs package babel/greek instead of marvosym (which
   523 broke \Rightarrow)
   524 
   525 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   526 textcomp package)
   527 
   528 
   529 
   530 New in Isabelle2002 (March 2002)
   531 --------------------------------
   532 
   533 *** Document preparation ***
   534 
   535 * greatly simplified document preparation setup, including more
   536 graceful interpretation of isatool usedir -i/-d/-D options, and more
   537 instructive isatool mkdir; users should basically be able to get
   538 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   539 users may run a separate document processing stage manually like this:
   540 "isatool usedir -D output HOL Test && isatool document Test/output";
   541 
   542 * theory dependency graph may now be incorporated into documents;
   543 isatool usedir -g true will produce session_graph.eps/.pdf for use
   544 with \includegraphics of LaTeX;
   545 
   546 * proper spacing of consecutive markup elements, especially text
   547 blocks after section headings;
   548 
   549 * support bold style (for single symbols only), input syntax is like
   550 this: "\<^bold>\<alpha>" or "\<^bold>A";
   551 
   552 * \<bullet> is now output as bold \cdot by default, which looks much
   553 better in printed text;
   554 
   555 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   556 note that these symbols are currently unavailable in Proof General /
   557 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   558 
   559 * isatool latex no longer depends on changed TEXINPUTS, instead
   560 isatool document copies the Isabelle style files to the target
   561 location;
   562 
   563 
   564 *** Isar ***
   565 
   566 * Pure/Provers: improved proof by cases and induction;
   567   - 'case' command admits impromptu naming of parameters (such as
   568     "case (Suc n)");
   569   - 'induct' method divinates rule instantiation from the inductive
   570     claim; no longer requires excessive ?P bindings for proper
   571     instantiation of cases;
   572   - 'induct' method properly enumerates all possibilities of set/type
   573     rules; as a consequence facts may be also passed through *type*
   574     rules without further ado;
   575   - 'induct' method now derives symbolic cases from the *rulified*
   576     rule (before it used to rulify cases stemming from the internal
   577     atomized version); this means that the context of a non-atomic
   578     statement becomes is included in the hypothesis, avoiding the
   579     slightly cumbersome show "PROP ?case" form;
   580   - 'induct' may now use elim-style induction rules without chaining
   581     facts, using ``missing'' premises from the goal state; this allows
   582     rules stemming from inductive sets to be applied in unstructured
   583     scripts, while still benefitting from proper handling of non-atomic
   584     statements; NB: major inductive premises need to be put first, all
   585     the rest of the goal is passed through the induction;
   586   - 'induct' proper support for mutual induction involving non-atomic
   587     rule statements (uses the new concept of simultaneous goals, see
   588     below);
   589   - append all possible rule selections, but only use the first
   590     success (no backtracking);
   591   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   592   - undeclared rule case names default to numbers 1, 2, 3, ...;
   593   - added 'print_induct_rules' (covered by help item in recent Proof
   594     General versions);
   595   - moved induct/cases attributes to Pure, methods to Provers;
   596   - generic method setup instantiated for FOL and HOL;
   597 
   598 * Pure: support multiple simultaneous goal statements, for example
   599 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   600 meta-level mechanism, this acts as if several individual goals had
   601 been stated separately; in particular common proof methods need to be
   602 repeated in order to cover all claims; note that a single elimination
   603 step is *not* sufficient to establish the two conjunctions, so this
   604 fails:
   605 
   606   assume "A & B" then have A and B ..   (*".." fails*)
   607 
   608 better use "obtain" in situations as above; alternative refer to
   609 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   610 
   611 * Pure: proper integration with ``locales''; unlike the original
   612 version by Florian Kammüller, Isar locales package high-level proof
   613 contexts rather than raw logical ones (e.g. we admit to include
   614 attributes everywhere); operations on locales include merge and
   615 rename; support for implicit arguments (``structures''); simultaneous
   616 type-inference over imports and text; see also HOL/ex/Locales.thy for
   617 some examples;
   618 
   619 * Pure: the following commands have been ``localized'', supporting a
   620 target locale specification "(in name)": 'lemma', 'theorem',
   621 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   622 stored both within the locale and at the theory level (exported and
   623 qualified by the locale name);
   624 
   625 * Pure: theory goals may now be specified in ``long'' form, with
   626 ad-hoc contexts consisting of arbitrary locale elements. for example
   627 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   628 definitions may be given, too); the result is a meta-level rule with
   629 the context elements being discharged in the obvious way;
   630 
   631 * Pure: new proof command 'using' allows to augment currently used
   632 facts after a goal statement ('using' is syntactically analogous to
   633 'apply', but acts on the goal's facts only); this allows chained facts
   634 to be separated into parts given before and after a claim, as in
   635 ``from a and b have C using d and e <proof>'';
   636 
   637 * Pure: renamed "antecedent" case to "rule_context";
   638 
   639 * Pure: new 'judgment' command records explicit information about the
   640 object-logic embedding (used by several tools internally); no longer
   641 use hard-wired "Trueprop";
   642 
   643 * Pure: added 'corollary' command;
   644 
   645 * Pure: fixed 'token_translation' command;
   646 
   647 * Pure: removed obsolete 'exported' attribute;
   648 
   649 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   650 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   651 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   652 
   653 * Pure: method 'atomize' presents local goal premises as object-level
   654 statements (atomic meta-level propositions); setup controlled via
   655 rewrite rules declarations of 'atomize' attribute; example
   656 application: 'induct' method with proper rule statements in improper
   657 proof *scripts*;
   658 
   659 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   660 now consider the syntactic context of assumptions, giving a better
   661 chance to get type-inference of the arguments right (this is
   662 especially important for locales);
   663 
   664 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   665 mode;
   666 
   667 * Pure/obtain: the formal conclusion "thesis", being marked as
   668 ``internal'', may no longer be reference directly in the text;
   669 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   670 situations;
   671 
   672 * Pure: generic 'sym' attribute which declares a rule both as pure
   673 'elim?' and for the 'symmetric' operation;
   674 
   675 * Pure: marginal comments ``--'' may now occur just anywhere in the
   676 text; the fixed correlation with particular command syntax has been
   677 discontinued;
   678 
   679 * Pure: new method 'rules' is particularly well-suited for proof
   680 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   681 but often produces more compact proof terms with less detours;
   682 
   683 * Pure/Provers/classical: simplified integration with pure rule
   684 attributes and methods; the classical "intro?/elim?/dest?"
   685 declarations coincide with the pure ones; the "rule" method no longer
   686 includes classically swapped intros; "intro" and "elim" methods no
   687 longer pick rules from the context; also got rid of ML declarations
   688 AddXIs/AddXEs/AddXDs; all of this has some potential for
   689 INCOMPATIBILITY;
   690 
   691 * Provers/classical: attribute 'swapped' produces classical inversions
   692 of introduction rules;
   693 
   694 * Provers/simplifier: 'simplified' attribute may refer to explicit
   695 rules instead of full simplifier context; 'iff' attribute handles
   696 conditional rules;
   697 
   698 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   699 
   700 * HOL: 'recdef' now fails on unfinished automated proofs, use
   701 "(permissive)" option to recover old behavior;
   702 
   703 * HOL: 'inductive' no longer features separate (collective) attributes
   704 for 'intros' (was found too confusing);
   705 
   706 * HOL: properly declared induction rules less_induct and
   707 wf_induct_rule;
   708 
   709 
   710 *** HOL ***
   711 
   712 * HOL: moved over to sane numeral syntax; the new policy is as
   713 follows:
   714 
   715   - 0 and 1 are polymorphic constants, which are defined on any
   716   numeric type (nat, int, real etc.);
   717 
   718   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   719   binary representation internally;
   720 
   721   - type nat has special constructor Suc, and generally prefers Suc 0
   722   over 1::nat and Suc (Suc 0) over 2::nat;
   723 
   724 This change may cause significant problems of INCOMPATIBILITY; here
   725 are some hints on converting existing sources:
   726 
   727   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   728   entities, so expressions involving "-" (unary or binary minus) need
   729   to be spaced properly;
   730 
   731   - existing occurrences of "1" may need to be constraint "1::nat" or
   732   even replaced by Suc 0; similar for old "2";
   733 
   734   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   735 
   736   - remove all special provisions on numerals in proofs;
   737 
   738 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   739 representation (depends on bin_arith_simps in the default context);
   740 
   741 * HOL: symbolic syntax for x^2 (numeral 2);
   742 
   743 * HOL: the class of all HOL types is now called "type" rather than
   744 "term"; INCOMPATIBILITY, need to adapt references to this type class
   745 in axclass/classes, instance/arities, and (usually rare) occurrences
   746 in typings (of consts etc.); internally the class is called
   747 "HOL.type", ML programs should refer to HOLogic.typeS;
   748 
   749 * HOL/record package improvements:
   750   - new derived operations "fields" to build a partial record section,
   751     "extend" to promote a fixed record to a record scheme, and
   752     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   753     declared as simp by default;
   754   - shared operations ("more", "fields", etc.) now need to be always
   755     qualified) --- potential INCOMPATIBILITY;
   756   - removed "make_scheme" operations (use "make" with "extend") --
   757     INCOMPATIBILITY;
   758   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   759   - provides cases/induct rules for use with corresponding Isar
   760     methods (for concrete records, record schemes, concrete more
   761     parts, and schematic more parts -- in that order);
   762   - internal definitions directly based on a light-weight abstract
   763     theory of product types over typedef rather than datatype;
   764 
   765 * HOL: generic code generator for generating executable ML code from
   766 specifications; specific support for HOL constructs such as inductive
   767 datatypes and sets, as well as recursive functions; can be invoked
   768 via 'generate_code' theory section;
   769 
   770 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   771 
   772 * HOL: consolidated and renamed several theories.  In particular:
   773         Ord.thy has been absorbed into HOL.thy
   774         String.thy has been absorbed into List.thy
   775 
   776 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   777 (beware of argument permutation!);
   778 
   779 * HOL: linorder_less_split superseded by linorder_cases;
   780 
   781 * HOL/List: "nodups" renamed to "distinct";
   782 
   783 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   784 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   785   - Ex_def has changed, now need to use some_eq_ex
   786 
   787 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   788 in this (rare) case use:
   789 
   790   delSWrapper "split_all_tac"
   791   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   792 
   793 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   794 MAY FAIL;
   795 
   796 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   797 Isabelle's type classes, ^ on functions and relations has too general
   798 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   799 necessary to attach explicit type constraints;
   800 
   801 * HOL/Relation: the prefix name of the infix "O" has been changed from
   802 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   803 renamed accordingly (eg "compI" -> "rel_compI").
   804 
   805 * HOL: syntax translations now work properly with numerals and records
   806 expressions;
   807 
   808 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   809 of "lam" -- INCOMPATIBILITY;
   810 
   811 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   812 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   813 renamed "Product_Type.unit";
   814 
   815 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   816 
   817 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   818 the "cases" method);
   819 
   820 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   821 Florian Kammüller);
   822 
   823 * HOL/IMP: updated and converted to new-style theory format; several
   824 parts turned into readable document, with proper Isar proof texts and
   825 some explanations (by Gerwin Klein);
   826 
   827 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   828 
   829 * HOL-Hyperreal is now a logic image;
   830 
   831 
   832 *** HOLCF ***
   833 
   834 * Isar: consts/constdefs supports mixfix syntax for continuous
   835 operations;
   836 
   837 * Isar: domain package adapted to new-style theory format, e.g. see
   838 HOLCF/ex/Dnat.thy;
   839 
   840 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   841 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   842 lift.induct_tac, always use UU instead of Undef;
   843 
   844 * HOLCF/IMP: updated and converted to new-style theory;
   845 
   846 
   847 *** ZF ***
   848 
   849 * Isar: proper integration of logic-specific tools and packages,
   850 including theory commands '(co)inductive', '(co)datatype',
   851 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   852 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   853 
   854 * theory Main no longer includes AC; for the Axiom of Choice, base
   855 your theory on Main_ZFC;
   856 
   857 * the integer library now covers quotients and remainders, with many
   858 laws relating division to addition, multiplication, etc.;
   859 
   860 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   861 typeless version of the formalism;
   862 
   863 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   864 format;
   865 
   866 * ZF/Induct: new directory for examples of inductive definitions,
   867 including theory Multiset for multiset orderings; converted to
   868 new-style theory format;
   869 
   870 * ZF: many new theorems about lists, ordinals, etc.;
   871 
   872 
   873 *** General ***
   874 
   875 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   876 variable proof controls level of detail: 0 = no proofs (only oracle
   877 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   878 also ref manual for further ML interfaces;
   879 
   880 * Pure/axclass: removed obsolete ML interface
   881 goal_subclass/goal_arity;
   882 
   883 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   884 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   885 separate tokens, so expressions involving minus need to be spaced
   886 properly;
   887 
   888 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   889 rather than "infixl" or "infixr";
   890 
   891 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   892 sort constraint specifications in type inference; e.g. "x::_::foo"
   893 ensures that the type of "x" is of sort "foo" (but not necessarily a
   894 type variable);
   895 
   896 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   897 control output of nested => (types); the default behavior is
   898 "type_brackets";
   899 
   900 * Pure/syntax: builtin parse translation for "_constify" turns valued
   901 tokens into AST constants;
   902 
   903 * Pure/syntax: prefer later declarations of translations and print
   904 translation functions; potential INCOMPATIBILITY: need to reverse
   905 multiple declarations for same syntax element constant;
   906 
   907 * Pure/show_hyps reset by default (in accordance to existing Isar
   908 practice);
   909 
   910 * Provers/classical: renamed addaltern to addafter, addSaltern to
   911 addSafter;
   912 
   913 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   914 as well;
   915 
   916 * system: tested support for MacOS X; should be able to get Isabelle +
   917 Proof General to work in a plain Terminal after installing Poly/ML
   918 (e.g. from the Isabelle distribution area) and GNU bash alone
   919 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   920 support requires further installations, e.g. from
   921 http://fink.sourceforge.net/);
   922 
   923 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   924 
   925 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   926 of 40 MB), cf. ML_OPTIONS;
   927 
   928 * system: Proof General keywords specification is now part of the
   929 Isabelle distribution (see etc/isar-keywords.el);
   930 
   931 * system: support for persistent Proof General sessions (refrain from
   932 outdating all loaded theories on startup); user may create writable
   933 logic images like this: ``isabelle -q HOL Test'';
   934 
   935 * system: smart selection of Isabelle process versus Isabelle
   936 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   937 run both "isabelle" and "Isabelle" even if file names are badly
   938 damaged (executable inspects the case of the first letter of its own
   939 name); added separate "isabelle-process" and "isabelle-interface";
   940 
   941 * system: refrain from any attempt at filtering input streams; no
   942 longer support ``8bit'' encoding of old isabelle font, instead proper
   943 iso-latin characters may now be used; the related isatools
   944 "symbolinput" and "nonascii" have disappeared as well;
   945 
   946 * system: removed old "xterm" interface (the print modes "xterm" and
   947 "xterm_color" are still available for direct use in a suitable
   948 terminal);
   949 
   950 
   951 
   952 New in Isabelle99-2 (February 2001)
   953 -----------------------------------
   954 
   955 *** Overview of INCOMPATIBILITIES ***
   956 
   957 * HOL: please note that theories in the Library and elsewhere often use the
   958 new-style (Isar) format; to refer to their theorems in an ML script you must
   959 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   960 
   961 * HOL: inductive package no longer splits induction rule aggressively,
   962 but only as far as specified by the introductions given; the old
   963 format may be recovered via ML function complete_split_rule or attribute
   964 'split_rule (complete)';
   965 
   966 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   967 gfp_Tarski to gfp_unfold;
   968 
   969 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   970 
   971 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   972 relation); infix "^^" has been renamed "``"; infix "``" has been
   973 renamed "`"; "univalent" has been renamed "single_valued";
   974 
   975 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   976 operation;
   977 
   978 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   979 
   980 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   981 
   982 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   983 consequence, it is no longer monotonic wrt. the local goal context
   984 (which is now passed through the inductive cases);
   985 
   986 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   987 \<gg> to \<ggreater>;
   988 
   989 
   990 *** Document preparation ***
   991 
   992 * \isabellestyle{NAME} selects version of Isabelle output (currently
   993 available: are "it" for near math-mode best-style output, "sl" for
   994 slanted text style, and "tt" for plain type-writer; if no
   995 \isabellestyle command is given, output is according to slanted
   996 type-writer);
   997 
   998 * support sub/super scripts (for single symbols only), input syntax is
   999 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1000 
  1001 * some more standard symbols; see Appendix A of the system manual for
  1002 the complete list of symbols defined in isabellesym.sty;
  1003 
  1004 * improved isabelle style files; more abstract symbol implementation
  1005 (should now use \isamath{...} and \isatext{...} in custom symbol
  1006 definitions);
  1007 
  1008 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1009 state; Note that presentation of goal states does not conform to
  1010 actual human-readable proof documents.  Please do not include goal
  1011 states into document output unless you really know what you are doing!
  1012 
  1013 * proper indentation of antiquoted output with proportional LaTeX
  1014 fonts;
  1015 
  1016 * no_document ML operator temporarily disables LaTeX document
  1017 generation;
  1018 
  1019 * isatool unsymbolize tunes sources for plain ASCII communication;
  1020 
  1021 
  1022 *** Isar ***
  1023 
  1024 * Pure: Isar now suffers initial goal statements to contain unbound
  1025 schematic variables (this does not conform to actual readable proof
  1026 documents, due to unpredictable outcome and non-compositional proof
  1027 checking); users who know what they are doing may use schematic goals
  1028 for Prolog-style synthesis of proven results;
  1029 
  1030 * Pure: assumption method (an implicit finishing) now handles actual
  1031 rules as well;
  1032 
  1033 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1034 initial goal, declare "that" only as Pure intro (only for single
  1035 steps); the "that" rule assumption may now be involved in implicit
  1036 finishing, thus ".." becomes a feasible for trivial obtains;
  1037 
  1038 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1039 instance proofs may be performed by "..";
  1040 
  1041 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1042 statements as well;
  1043 
  1044 * Pure: more robust selection of calculational rules;
  1045 
  1046 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1047 rule (as well as the assumption rule);
  1048 
  1049 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1050 lemmas, using the graph browser tool;
  1051 
  1052 * Pure: predict failure of "show" in interactive mode;
  1053 
  1054 * Pure: 'thms_containing' now takes actual terms as arguments;
  1055 
  1056 * HOL: improved method 'induct' --- now handles non-atomic goals
  1057 (potential INCOMPATIBILITY); tuned error handling;
  1058 
  1059 * HOL: cases and induct rules now provide explicit hints about the
  1060 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1061 any remaining facts are inserted into the goal verbatim;
  1062 
  1063 * HOL: local contexts (aka cases) may now contain term bindings as
  1064 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1065 the result to be shown in each case;
  1066 
  1067 * HOL: added 'recdef_tc' command;
  1068 
  1069 * isatool convert assists in eliminating legacy ML scripts;
  1070 
  1071 
  1072 *** HOL ***
  1073 
  1074 * HOL/Library: a collection of generic theories to be used together
  1075 with main HOL; the theory loader path already includes this directory
  1076 by default; the following existing theories have been moved here:
  1077 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1078 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1079 
  1080 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1081 modelling and verification task performed in Isabelle/HOL +
  1082 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1083 
  1084 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1085 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1086 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1087 'domain', this makes the theory consistent with mathematical
  1088 literature;
  1089 
  1090 * HOL basics: added overloaded operations "inverse" and "divide"
  1091 (infix "/"), syntax for generic "abs" operation, generic summation
  1092 operator \<Sum>;
  1093 
  1094 * HOL/typedef: simplified package, provide more useful rules (see also
  1095 HOL/subset.thy);
  1096 
  1097 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1098 now expressed as a proper nested rule (old-style tactic scripts may
  1099 require atomize_strip_tac to cope with non-atomic premises);
  1100 
  1101 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1102 to "split_conv" (old name still available for compatibility);
  1103 
  1104 * HOL: improved concrete syntax for strings (e.g. allows translation
  1105 rules with string literals);
  1106 
  1107 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1108  and Fleuriot's mechanization of analysis, including the transcendental
  1109  functions for the reals;
  1110 
  1111 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1112 
  1113 
  1114 *** CTT ***
  1115 
  1116 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1117 "lam" is displayed as TWO lambda-symbols
  1118 
  1119 * CTT: theory Main now available, containing everything (that is, Bool
  1120 and Arith);
  1121 
  1122 
  1123 *** General ***
  1124 
  1125 * Pure: the Simplifier has been implemented properly as a derived rule
  1126 outside of the actual kernel (at last!); the overall performance
  1127 penalty in practical applications is about 50%, while reliability of
  1128 the Isabelle inference kernel has been greatly improved;
  1129 
  1130 * print modes "brackets" and "no_brackets" control output of nested =>
  1131 (types) and ==> (props); the default behaviour is "brackets";
  1132 
  1133 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1134 as assumptions as well;
  1135 
  1136 * system: support Poly/ML 4.0;
  1137 
  1138 * system: isatool install handles KDE version 1 or 2;
  1139 
  1140 
  1141 
  1142 New in Isabelle99-1 (October 2000)
  1143 ----------------------------------
  1144 
  1145 *** Overview of INCOMPATIBILITIES ***
  1146 
  1147 * HOL: simplification of natural numbers is much changed; to partly
  1148 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1149 issue the following ML commands:
  1150 
  1151   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1152   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1153 
  1154 * HOL: simplification no longer dives into case-expressions; this is
  1155 controlled by "t.weak_case_cong" for each datatype t;
  1156 
  1157 * HOL: nat_less_induct renamed to less_induct;
  1158 
  1159 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1160 fixsome to patch .thy and .ML sources automatically;
  1161 
  1162   select_equality  -> some_equality
  1163   select_eq_Ex     -> some_eq_ex
  1164   selectI2EX       -> someI2_ex
  1165   selectI2         -> someI2
  1166   selectI          -> someI
  1167   select1_equality -> some1_equality
  1168   Eps_sym_eq       -> some_sym_eq_trivial
  1169   Eps_eq           -> some_eq_trivial
  1170 
  1171 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1172 
  1173 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1174 instead);
  1175 
  1176 * HOL: the recursion equations generated by 'recdef' are now called
  1177 f.simps instead of f.rules;
  1178 
  1179 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1180 
  1181 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1182 sometimes be needed;
  1183 
  1184 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1185 
  1186 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1187 
  1188 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1189 product is now "<*>" instead of "Times"; the lexicographic product is
  1190 now "<*lex*>" instead of "**";
  1191 
  1192 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1193 of main HOL, but was unused); better use HOL's datatype package;
  1194 
  1195 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1196 the old syntax may be recovered as follows:
  1197 
  1198   syntax (symbols)
  1199     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1200       (infixl "\\<oplus>" 100)
  1201 
  1202 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1203 
  1204 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1205 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1206 internally;
  1207 
  1208 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1209 changed from A/r to A//r;
  1210 
  1211 * ZF: new treatment of arithmetic (nat & int) may break some old
  1212 proofs;
  1213 
  1214 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1215 rulify -> rule_format, elimify -> elim_format, ...);
  1216 
  1217 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1218 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1219 should have to change intro!! to intro? only); replaced "delrule" by
  1220 "rule del";
  1221 
  1222 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1223 
  1224 * Provers: strengthened force_tac by using new first_best_tac;
  1225 
  1226 * LaTeX document preparation: several changes of isabelle.sty (see
  1227 lib/texinputs);
  1228 
  1229 
  1230 *** Document preparation ***
  1231 
  1232 * formal comments (text blocks etc.) in new-style theories may now
  1233 contain antiquotations of thm/prop/term/typ/text to be presented
  1234 according to latex print mode; concrete syntax is like this:
  1235 @{term[show_types] "f(x) = a + x"};
  1236 
  1237 * isatool mkdir provides easy setup of Isabelle session directories,
  1238 including proper document sources;
  1239 
  1240 * generated LaTeX sources are now deleted after successful run
  1241 (isatool document -c); may retain a copy somewhere else via -D option
  1242 of isatool usedir;
  1243 
  1244 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1245 style files, achieving self-contained LaTeX sources and simplifying
  1246 LaTeX debugging;
  1247 
  1248 * old-style theories now produce (crude) LaTeX output as well;
  1249 
  1250 * browser info session directories are now self-contained (may be put
  1251 on WWW server seperately); improved graphs of nested sessions; removed
  1252 graph for 'all sessions';
  1253 
  1254 * several improvements in isabelle style files; \isabellestyle{it}
  1255 produces fake math mode output; \isamarkupheader is now \section by
  1256 default; see lib/texinputs/isabelle.sty etc.;
  1257 
  1258 
  1259 *** Isar ***
  1260 
  1261 * Isar/Pure: local results and corresponding term bindings are now
  1262 subject to Hindley-Milner polymorphism (similar to ML); this
  1263 accommodates incremental type-inference very nicely;
  1264 
  1265 * Isar/Pure: new derived language element 'obtain' supports
  1266 generalized existence reasoning;
  1267 
  1268 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1269 support accumulation of results, without applying any rules yet;
  1270 useful to collect intermediate results without explicit name
  1271 references, and for use with transitivity rules with more than 2
  1272 premises;
  1273 
  1274 * Isar/Pure: scalable support for case-analysis type proofs: new
  1275 'case' language element refers to local contexts symbolically, as
  1276 produced by certain proof methods; internally, case names are attached
  1277 to theorems as "tags";
  1278 
  1279 * Isar/Pure: theory command 'hide' removes declarations from
  1280 class/type/const name spaces;
  1281 
  1282 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1283 indicate potential overloading;
  1284 
  1285 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1286 
  1287 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1288 "{a,b,c}" instead of {a,b,c};
  1289 
  1290 * Isar/Pure now provides its own version of intro/elim/dest
  1291 attributes; useful for building new logics, but beware of confusion
  1292 with the version in Provers/classical;
  1293 
  1294 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1295 case name 'antecedent';
  1296 
  1297 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1298 to the current context is now done automatically);
  1299 
  1300 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1301 for definining proof methods in ML;
  1302 
  1303 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1304 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1305 most cases, one should have to change intro!! to intro? only);
  1306 replaced "delrule" by "rule del";
  1307 
  1308 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1309 'symmetric' attribute (the latter supercedes [RS sym]);
  1310 
  1311 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1312 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1313 well (including splits);
  1314 
  1315 * Isar/Provers: Simplifier and Classical methods now support all kind
  1316 of modifiers used in the past, including 'cong', 'iff', etc.
  1317 
  1318 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1319 of Simplifier and Classical reasoner);
  1320 
  1321 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1322 now support named cases; major packages (inductive, datatype, primrec,
  1323 recdef) support case names and properly name parameters;
  1324 
  1325 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1326 monotonicity conditions are extracted to be proven at end of
  1327 calculations;
  1328 
  1329 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1330 method anyway;
  1331 
  1332 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1333 split_if split_if_asm; datatype package provides theorems foo.splits =
  1334 foo.split foo.split_asm for each datatype;
  1335 
  1336 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1337 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1338 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1339 use "(cases (simplified))" method in proper proof texts);
  1340 
  1341 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1342 
  1343 * Isar: names of theorems etc. may be natural numbers as well;
  1344 
  1345 * Isar: 'pr' command: optional arguments for goals_limit and
  1346 ProofContext.prems_limit; no longer prints theory contexts, but only
  1347 proof states;
  1348 
  1349 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1350 additional print modes to be specified; e.g. "pr(latex)" will print
  1351 proof state according to the Isabelle LaTeX style;
  1352 
  1353 * Isar: improved support for emulating tactic scripts, including proof
  1354 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1355 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1356 (for HOL datatypes);
  1357 
  1358 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1359 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1360 'proof method scripts' have to be in depth-first order;
  1361 
  1362 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1363 
  1364 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1365 should instead use individual commands for printing items
  1366 (print_commands, print_methods etc.);
  1367 
  1368 * Isar: added 'nothing' --- the empty list of theorems;
  1369 
  1370 
  1371 *** HOL ***
  1372 
  1373 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1374 corresponding virtual machine and a specification of its bytecode
  1375 verifier and a lightweight bytecode verifier, including proofs of
  1376 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1377 Cornelia Pusch (see also the homepage of project Bali at
  1378 http://isabelle.in.tum.de/Bali/);
  1379 
  1380 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1381 Clemens Ballarin;
  1382 
  1383 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1384 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1385 Rasmussen;
  1386 
  1387 * HOL/Lattice: fundamental concepts of lattice theory and order
  1388 structures, including duals, properties of bounds versus algebraic
  1389 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1390 Theorem for complete lattices etc.; may also serve as a demonstration
  1391 for abstract algebraic reasoning using axiomatic type classes, and
  1392 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1393 
  1394 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1395 von Oheimb;
  1396 
  1397 * HOL/IMPP: extension of IMP with local variables and mutually
  1398 recursive procedures, by David von Oheimb;
  1399 
  1400 * HOL/Lambda: converted into new-style theory and document;
  1401 
  1402 * HOL/ex/Multiquote: example of multiple nested quotations and
  1403 anti-quotations -- basically a generalized version of de-Bruijn
  1404 representation; very useful in avoiding lifting of operations;
  1405 
  1406 * HOL/record: added general record equality rule to simpset; fixed
  1407 select-update simplification procedure to handle extended records as
  1408 well; admit "r" as field name;
  1409 
  1410 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1411 other numeric types and also as the identity of groups, rings, etc.;
  1412 
  1413 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1414 Types nat and int belong to this axclass;
  1415 
  1416 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1417    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1418    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1419   two terms #m*u and #n*u are replaced by #(m+n)*u
  1420     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1421   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1422     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1423 
  1424 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1425 powerful prover for predicate logic but knows nothing of clasets; see
  1426 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1427 
  1428 * HOL: new version of "case_tac" subsumes both boolean case split and
  1429 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1430 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1431 
  1432 * HOL: simplification no longer dives into case-expressions: only the
  1433 selector expression is simplified, but not the remaining arms; to
  1434 enable full simplification of case-expressions for datatype t, you may
  1435 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1436 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1437 
  1438 * HOL/recdef: the recursion equations generated by 'recdef' for
  1439 function 'f' are now called f.simps instead of f.rules; if all
  1440 termination conditions are proved automatically, these simplification
  1441 rules are added to the simpset, as in primrec; rules may be named
  1442 individually as well, resulting in a separate list of theorems for
  1443 each equation;
  1444 
  1445 * HOL/While is a new theory that provides a while-combinator. It
  1446 permits the definition of tail-recursive functions without the
  1447 provision of a termination measure. The latter is necessary once the
  1448 invariant proof rule for while is applied.
  1449 
  1450 * HOL: new (overloaded) notation for the set of elements below/above
  1451 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1452 
  1453 * HOL: theorems impI, allI, ballI bound as "strip";
  1454 
  1455 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1456 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1457 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1458 
  1459 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1460 
  1461 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1462 main HOL, but was unused);
  1463 
  1464 * HOL: fewer consts declared as global (e.g. have to refer to
  1465 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1466 
  1467 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1468 in case of overlap with user translations (e.g. judgements over
  1469 tuples); (note that the underlying logical represenation is still
  1470 bogus);
  1471 
  1472 
  1473 *** ZF ***
  1474 
  1475 * ZF: simplification automatically cancels common terms in arithmetic
  1476 expressions over nat and int;
  1477 
  1478 * ZF: new treatment of nat to minimize type-checking: all operators
  1479 coerce their operands to a natural number using the function natify,
  1480 making the algebraic laws unconditional;
  1481 
  1482 * ZF: as above, for int: operators coerce their operands to an integer
  1483 using the function intify;
  1484 
  1485 * ZF: the integer library now contains many of the usual laws for the
  1486 orderings, including $<=, and monotonicity laws for $+ and $*;
  1487 
  1488 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1489 simplification;
  1490 
  1491 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1492 to the simplifier and classical reasoner simultaneously;
  1493 
  1494 
  1495 *** General ***
  1496 
  1497 * Provers: blast_tac now handles actual object-logic rules as
  1498 assumptions; note that auto_tac uses blast_tac internally as well;
  1499 
  1500 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1501 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1502 
  1503 * Provers: delrules now handles destruct rules as well (no longer need
  1504 explicit make_elim);
  1505 
  1506 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1507   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1508 use instead the strong form,
  1509   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1510 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1511 from destruct-rules;
  1512 
  1513 * Provers: Simplifier.easy_setup provides a fast path to basic
  1514 Simplifier setup for new object-logics;
  1515 
  1516 * Pure: AST translation rules no longer require constant head on LHS;
  1517 
  1518 * Pure: improved name spaces: ambiguous output is qualified; support
  1519 for hiding of names;
  1520 
  1521 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1522 XSYMBOL_HOME; no longer need to do manual configuration in most
  1523 situations;
  1524 
  1525 * system: compression of ML heaps images may now be controlled via -c
  1526 option of isabelle and isatool usedir (currently only observed by
  1527 Poly/ML);
  1528 
  1529 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1530 useful for remote X11);
  1531 
  1532 * system: provide TAGS file for Isabelle sources;
  1533 
  1534 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1535 order;
  1536 
  1537 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1538 timing flag supersedes proof_timing and Toplevel.trace;
  1539 
  1540 * ML: new combinators |>> and |>>> for incremental transformations
  1541 with secondary results (e.g. certain theory extensions):
  1542 
  1543 * ML: PureThy.add_defs gets additional argument to indicate potential
  1544 overloading (usually false);
  1545 
  1546 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1547 results;
  1548 
  1549 
  1550 
  1551 New in Isabelle99 (October 1999)
  1552 --------------------------------
  1553 
  1554 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1555 
  1556 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1557 are no longer simplified.  (This allows the simplifier to unfold recursive
  1558 functional programs.)  To restore the old behaviour, declare
  1559 
  1560     Delcongs [if_weak_cong];
  1561 
  1562 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1563 complement;
  1564 
  1565 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1566 
  1567 * HOL/datatype: mutual_induct_tac no longer exists --
  1568   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1569 
  1570 * HOL/typedef: fixed type inference for representing set; type
  1571 arguments now have to occur explicitly on the rhs as type constraints;
  1572 
  1573 * ZF: The con_defs part of an inductive definition may no longer refer
  1574 to constants declared in the same theory;
  1575 
  1576 * HOL, ZF: the function mk_cases, generated by the inductive
  1577 definition package, has lost an argument.  To simplify its result, it
  1578 uses the default simpset instead of a supplied list of theorems.
  1579 
  1580 * HOL/List: the constructors of type list are now Nil and Cons;
  1581 
  1582 * Simplifier: the type of the infix ML functions
  1583         setSSolver addSSolver setSolver addSolver
  1584 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1585 for packaging solvers. A solver is created via
  1586         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1587 where the string argument is only a comment.
  1588 
  1589 
  1590 *** Proof tools ***
  1591 
  1592 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1593 decision procedure for linear arithmetic. Currently it is used for
  1594 types `nat', `int', and `real' in HOL (see below); it can, should and
  1595 will be instantiated for other types and logics as well.
  1596 
  1597 * The simplifier now accepts rewrite rules with flexible heads, eg
  1598      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1599   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1600   matching.
  1601 
  1602 
  1603 *** General ***
  1604 
  1605 * New Isabelle/Isar subsystem provides an alternative to traditional
  1606 tactical theorem proving; together with the ProofGeneral/isar user
  1607 interface it offers an interactive environment for developing human
  1608 readable proof documents (Isar == Intelligible semi-automated
  1609 reasoning); for further information see isatool doc isar-ref,
  1610 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1611 
  1612 * improved and simplified presentation of theories: better HTML markup
  1613 (including colors), graph views in several sizes; isatool usedir now
  1614 provides a proper interface for user theories (via -P option); actual
  1615 document preparation based on (PDF)LaTeX is available as well (for
  1616 new-style theories only); see isatool doc system for more information;
  1617 
  1618 * native support for Proof General, both for classic Isabelle and
  1619 Isabelle/Isar;
  1620 
  1621 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1622 using the graph browser tool;
  1623 
  1624 * Isabelle manuals now also available as PDF;
  1625 
  1626 * theory loader rewritten from scratch (may not be fully
  1627 bug-compatible); old loadpath variable has been replaced by show_path,
  1628 add_path, del_path, reset_path functions; new operations such as
  1629 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1630 isatool doc ref);
  1631 
  1632 * improved isatool install: option -k creates KDE application icon,
  1633 option -p DIR installs standalone binaries;
  1634 
  1635 * added ML_PLATFORM setting (useful for cross-platform installations);
  1636 more robust handling of platform specific ML images for SML/NJ;
  1637 
  1638 * the settings environment is now statically scoped, i.e. it is never
  1639 created again in sub-processes invoked from isabelle, isatool, or
  1640 Isabelle;
  1641 
  1642 * path element specification '~~' refers to '$ISABELLE_HOME';
  1643 
  1644 * in locales, the "assumes" and "defines" parts may be omitted if
  1645 empty;
  1646 
  1647 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1648 long arrows);
  1649 
  1650 * new print_mode "HTML";
  1651 
  1652 * new flag show_tags controls display of tags of theorems (which are
  1653 basically just comments that may be attached by some tools);
  1654 
  1655 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1656 mode and goal output format:
  1657 
  1658 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1659 244c244
  1660 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1661 ---
  1662 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1663 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1664 181c181
  1665 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1666 ---
  1667 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1668 
  1669 * function bind_thms stores lists of theorems (cf. bind_thm);
  1670 
  1671 * new shorthand tactics ftac, eatac, datac, fatac;
  1672 
  1673 * qed (and friends) now accept "" as result name; in that case the
  1674 theorem is not stored, but proper checks and presentation of the
  1675 result still apply;
  1676 
  1677 * theorem database now also indexes constants "Trueprop", "all",
  1678 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1679 
  1680 
  1681 *** HOL ***
  1682 
  1683 ** HOL arithmetic **
  1684 
  1685 * There are now decision procedures for linear arithmetic over nat and
  1686 int:
  1687 
  1688 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1689 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1690 are treated as atomic; subformulae not involving type `nat' or `int'
  1691 are ignored; quantified subformulae are ignored unless they are
  1692 positive universal or negative existential. The tactic has to be
  1693 invoked by hand and can be a little bit slow. In particular, the
  1694 running time is exponential in the number of occurrences of `min' and
  1695 `max', and `-' on `nat'.
  1696 
  1697 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1698 (negated) (in)equalities among the premises and the conclusion into
  1699 account (i.e. no compound formulae) and does not know about `min' and
  1700 `max', and `-' on `nat'. It is fast and is used automatically by the
  1701 simplifier.
  1702 
  1703 NB: At the moment, these decision procedures do not cope with mixed
  1704 nat/int formulae where the two parts interact, such as `m < n ==>
  1705 int(m) < int(n)'.
  1706 
  1707 * HOL/Numeral provides a generic theory of numerals (encoded
  1708 efficiently as bit strings); setup for types nat/int/real is in place;
  1709 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1710 int, existing theories and proof scripts may require a few additional
  1711 type constraints;
  1712 
  1713 * integer division and remainder can now be performed on constant
  1714 arguments;
  1715 
  1716 * many properties of integer multiplication, division and remainder
  1717 are now available;
  1718 
  1719 * An interface to the Stanford Validity Checker (SVC) is available through the
  1720 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1721 are proved automatically.  SVC must be installed separately, and its results
  1722 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1723 invocation of the underlying oracle).  For SVC see
  1724   http://verify.stanford.edu/SVC
  1725 
  1726 * IsaMakefile: the HOL-Real target now builds an actual image;
  1727 
  1728 
  1729 ** HOL misc **
  1730 
  1731 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1732 (in Isabelle/Isar) -- by Gertrud Bauer;
  1733 
  1734 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1735 analysis for assembly languages with subtypes;
  1736 
  1737 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1738 -- avoids syntactic ambiguities and treats state, transition, and
  1739 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1740 changed syntax and (many) tactics;
  1741 
  1742 * HOL/inductive: Now also handles more general introduction rules such
  1743   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1744   theorems are now maintained within the theory (maintained via the
  1745   "mono" attribute);
  1746 
  1747 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1748   (using function types) such as
  1749 
  1750   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1751 
  1752 * HOL/record: record_simproc (part of the default simpset) takes care
  1753 of selectors applied to updated records; record_split_tac is no longer
  1754 part of the default claset; update_defs may now be removed from the
  1755 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1756 
  1757   claset_ref () := claset() addSWrapper record_split_wrapper;
  1758   Delsimprocs [record_simproc]
  1759 
  1760 * HOL/typedef: fixed type inference for representing set; type
  1761 arguments now have to occur explicitly on the rhs as type constraints;
  1762 
  1763 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1764 names rather than an ML expression;
  1765 
  1766 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1767 supplied later.  Program schemes can be defined, such as
  1768     "While B C s = (if B s then While B C (C s) else s)"
  1769 where the well-founded relation can be chosen after B and C have been given.
  1770 
  1771 * HOL/List: the constructors of type list are now Nil and Cons;
  1772 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1773 course, ML tools referring to List.list.op # etc. have to be adapted;
  1774 
  1775 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1776 disabled by default; run isabelle with option -m HOL to get back to
  1777 the original Gordon/HOL-style output;
  1778 
  1779 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1780 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1781 
  1782 * HOL basic syntax simplified (more orthogonal): all variants of
  1783 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1784 Eps operator is provided as well: "SOME x. P[x]";
  1785 
  1786 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1787 
  1788 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1789 thus available for user theories;
  1790 
  1791 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1792 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1793 time;
  1794 
  1795 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1796 several times and then mp;
  1797 
  1798 
  1799 *** LK ***
  1800 
  1801 * the notation <<...>> is now available as a notation for sequences of
  1802 formulas;
  1803 
  1804 * the simplifier is now installed
  1805 
  1806 * the axiom system has been generalized (thanks to Soren Heilmann)
  1807 
  1808 * the classical reasoner now has a default rule database
  1809 
  1810 
  1811 *** ZF ***
  1812 
  1813 * new primrec section allows primitive recursive functions to be given
  1814 directly (as in HOL) over datatypes and the natural numbers;
  1815 
  1816 * new tactics induct_tac and exhaust_tac for induction (or case
  1817 analysis) over datatypes and the natural numbers;
  1818 
  1819 * the datatype declaration of type T now defines the recursor T_rec;
  1820 
  1821 * simplification automatically does freeness reasoning for datatype
  1822 constructors;
  1823 
  1824 * automatic type-inference, with AddTCs command to insert new
  1825 type-checking rules;
  1826 
  1827 * datatype introduction rules are now added as Safe Introduction rules
  1828 to the claset;
  1829 
  1830 * the syntax "if P then x else y" is now available in addition to
  1831 if(P,x,y);
  1832 
  1833 
  1834 *** Internal programming interfaces ***
  1835 
  1836 * tuned simplifier trace output; new flag debug_simp;
  1837 
  1838 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1839 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1840 
  1841 * AxClass.axclass_tac lost the theory argument;
  1842 
  1843 * tuned current_goals_markers semantics: begin / end goal avoids
  1844 printing empty lines;
  1845 
  1846 * removed prs and prs_fn hook, which was broken because it did not
  1847 include \n in its semantics, forcing writeln to add one
  1848 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1849 string -> unit if you really want to output text without newline;
  1850 
  1851 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1852 plain output, interface builders may have to enable 'isabelle_font'
  1853 mode to get Isabelle font glyphs as before;
  1854 
  1855 * refined token_translation interface; INCOMPATIBILITY: output length
  1856 now of type real instead of int;
  1857 
  1858 * theory loader actions may be traced via new ThyInfo.add_hook
  1859 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1860 your own database of information attached to *whole* theories -- as
  1861 opposed to intra-theory data slots offered via TheoryDataFun;
  1862 
  1863 * proper handling of dangling sort hypotheses (at last!);
  1864 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1865 extra sort hypotheses that can be witnessed from the type signature;
  1866 the force_strip_shyps flag is gone, any remaining shyps are simply
  1867 left in the theorem (with a warning issued by strip_shyps_warning);
  1868 
  1869 
  1870 
  1871 New in Isabelle98-1 (October 1998)
  1872 ----------------------------------
  1873 
  1874 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1875 
  1876 * several changes of automated proof tools;
  1877 
  1878 * HOL: major changes to the inductive and datatype packages, including
  1879 some minor incompatibilities of theory syntax;
  1880 
  1881 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1882 called `inj_on';
  1883 
  1884 * HOL: removed duplicate thms in Arith:
  1885   less_imp_add_less  should be replaced by  trans_less_add1
  1886   le_imp_add_le      should be replaced by  trans_le_add1
  1887 
  1888 * HOL: unary minus is now overloaded (new type constraints may be
  1889 required);
  1890 
  1891 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1892 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1893 now taken as an integer constant.
  1894 
  1895 * Pure: ML function 'theory_of' renamed to 'theory';
  1896 
  1897 
  1898 *** Proof tools ***
  1899 
  1900 * Simplifier:
  1901   1. Asm_full_simp_tac is now more aggressive.
  1902      1. It will sometimes reorient premises if that increases their power to
  1903         simplify.
  1904      2. It does no longer proceed strictly from left to right but may also
  1905         rotate premises to achieve further simplification.
  1906      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1907      old Asm_full_simp_tac in that it does not rotate premises.
  1908   2. The simplifier now knows a little bit about nat-arithmetic.
  1909 
  1910 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1911 allows for selected deletion of wrappers, by introduction of names for
  1912 wrapper functionals.  This implies that addbefore, addSbefore,
  1913 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1914 and that adding two tactics with the same name overwrites the first
  1915 one (emitting a warning).
  1916   type wrapper = (int -> tactic) -> (int -> tactic)
  1917   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1918   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1919   delWrapper, delSWrapper: claset *  string            -> claset
  1920   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1921 
  1922 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1923 semantics; addbefore now affects only the unsafe part of step_tac
  1924 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1925 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1926 by Force_tac;
  1927 
  1928 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1929 compWrapper; added safe wrapper (and access functions for it);
  1930 
  1931 * HOL/split_all_tac is now much faster and fails if there is nothing
  1932 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1933 and the names of the automatically generated variables have changed.
  1934 split_all_tac has moved within claset() from unsafe wrappers to safe
  1935 wrappers, which means that !!-bound variables are split much more
  1936 aggressively, and safe_tac and clarify_tac now split such variables.
  1937 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1938 Note: the same holds for record_split_tac, which does the job of
  1939 split_all_tac for record fields.
  1940 
  1941 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1942 permanently to the default simpset using Addsplits just like
  1943 Addsimps. They can be removed via Delsplits just like
  1944 Delsimps. Lower-case versions are also available.
  1945 
  1946 * HOL/Simplifier: The rule split_if is now part of the default
  1947 simpset. This means that the simplifier will eliminate all occurrences
  1948 of if-then-else in the conclusion of a goal. To prevent this, you can
  1949 either remove split_if completely from the default simpset by
  1950 `Delsplits [split_if]' or remove it in a specific call of the
  1951 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1952 other case splitting rules to/from the default simpset: every datatype
  1953 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1954 t is the name of the datatype).
  1955 
  1956 * Classical reasoner / Simplifier combination: new force_tac (and
  1957 derivatives Force_tac, force) combines rewriting and classical
  1958 reasoning (and whatever other tools) similarly to auto_tac, but is
  1959 aimed to solve the given subgoal completely.
  1960 
  1961 
  1962 *** General ***
  1963 
  1964 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1965 and `goalw': the theory is no longer needed as an explicit argument -
  1966 the current theory context is used; assumptions are no longer returned
  1967 at the ML-level unless one of them starts with ==> or !!; it is
  1968 recommended to convert to these new commands using isatool fixgoal
  1969 (backup your sources first!);
  1970 
  1971 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1972 the current theory context, and 'theory' to lookup stored theories;
  1973 
  1974 * new theory section 'locale' for declaring constants, assumptions and
  1975 definitions that have local scope;
  1976 
  1977 * new theory section 'nonterminals' for purely syntactic types;
  1978 
  1979 * new theory section 'setup' for generic ML setup functions
  1980 (e.g. package initialization);
  1981 
  1982 * the distribution now includes Isabelle icons: see
  1983 lib/logo/isabelle-{small,tiny}.xpm;
  1984 
  1985 * isatool install - install binaries with absolute references to
  1986 ISABELLE_HOME/bin;
  1987 
  1988 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1989 
  1990 * print mode 'emacs' reserved for Isamode;
  1991 
  1992 * support multiple print (ast) translations per constant name;
  1993 
  1994 * theorems involving oracles are now printed with a suffixed [!];
  1995 
  1996 
  1997 *** HOL ***
  1998 
  1999 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2000 
  2001 * HOL/inductive package reorganized and improved: now supports mutual
  2002 definitions such as
  2003 
  2004   inductive EVEN ODD
  2005     intrs
  2006       null "0 : EVEN"
  2007       oddI "n : EVEN ==> Suc n : ODD"
  2008       evenI "n : ODD ==> Suc n : EVEN"
  2009 
  2010 new theorem list "elims" contains an elimination rule for each of the
  2011 recursive sets; inductive definitions now handle disjunctive premises
  2012 correctly (also ZF);
  2013 
  2014 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2015 "mutual_induct" no longer exists - the induction rule is always
  2016 contained in "induct";
  2017 
  2018 
  2019 * HOL/datatype package re-implemented and greatly improved: now
  2020 supports mutually recursive datatypes such as
  2021 
  2022   datatype
  2023     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2024             | SUM ('a aexp) ('a aexp)
  2025             | DIFF ('a aexp) ('a aexp)
  2026             | NUM 'a
  2027   and
  2028     'a bexp = LESS ('a aexp) ('a aexp)
  2029             | AND ('a bexp) ('a bexp)
  2030             | OR ('a bexp) ('a bexp)
  2031 
  2032 as well as indirectly recursive datatypes such as
  2033 
  2034   datatype
  2035     ('a, 'b) term = Var 'a
  2036                   | App 'b ((('a, 'b) term) list)
  2037 
  2038 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2039 induction on mutually / indirectly recursive datatypes.
  2040 
  2041 Primrec equations are now stored in theory and can be accessed via
  2042 <function_name>.simps.
  2043 
  2044 INCOMPATIBILITIES:
  2045 
  2046   - Theories using datatypes must now have theory Datatype as an
  2047     ancestor.
  2048   - The specific <typename>.induct_tac no longer exists - use the
  2049     generic induct_tac instead.
  2050   - natE has been renamed to nat.exhaust - use exhaust_tac
  2051     instead of res_inst_tac ... natE. Note that the variable
  2052     names in nat.exhaust differ from the names in natE, this
  2053     may cause some "fragile" proofs to fail.
  2054   - The theorems split_<typename>_case and split_<typename>_case_asm
  2055     have been renamed to <typename>.split and <typename>.split_asm.
  2056   - Since default sorts of type variables are now handled correctly,
  2057     some datatype definitions may have to be annotated with explicit
  2058     sort constraints.
  2059   - Primrec definitions no longer require function name and type
  2060     of recursive argument.
  2061 
  2062 Consider using isatool fixdatatype to adapt your theories and proof
  2063 scripts to the new package (backup your sources first!).
  2064 
  2065 
  2066 * HOL/record package: considerably improved implementation; now
  2067 includes concrete syntax for record types, terms, updates; theorems
  2068 for surjective pairing and splitting !!-bound record variables; proof
  2069 support is as follows:
  2070 
  2071   1) standard conversions (selectors or updates applied to record
  2072 constructor terms) are part of the standard simpset;
  2073 
  2074   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2075 made part of standard simpset and claset via addIffs;
  2076 
  2077   3) a tactic for record field splitting (record_split_tac) is part of
  2078 the standard claset (addSWrapper);
  2079 
  2080 To get a better idea about these rules you may retrieve them via
  2081 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2082 the name of your record type.
  2083 
  2084 The split tactic 3) conceptually simplifies by the following rule:
  2085 
  2086   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2087 
  2088 Thus any record variable that is bound by meta-all will automatically
  2089 blow up into some record constructor term, consequently the
  2090 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2091 solve record problems automatically.
  2092 
  2093 
  2094 * reorganized the main HOL image: HOL/Integ and String loaded by
  2095 default; theory Main includes everything;
  2096 
  2097 * automatic simplification of integer sums and comparisons, using cancellation;
  2098 
  2099 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2100 
  2101 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2102 
  2103 * many new identities for unions, intersections, set difference, etc.;
  2104 
  2105 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2106 called split_if, split_split, split_sum_case and split_nat_case (to go
  2107 with add/delsplits);
  2108 
  2109 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2110 (?x::unit) = (); this is made part of the default simpset, which COULD
  2111 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2112 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2113 unit_abs_eta_conv is added in order to counter the effect of
  2114 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2115 %u.f();
  2116 
  2117 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2118 makes more sense);
  2119 
  2120 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2121   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2122   disjointness reasoning but breaking a few old proofs.
  2123 
  2124 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2125 to 'converse' from 'inverse' (for compatibility with ZF and some
  2126 literature);
  2127 
  2128 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2129 the well-founded relation;
  2130 
  2131 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2132     Compl A.  The "Compl" syntax remains available as input syntax for this
  2133     release ONLY.
  2134 
  2135 * HOL/Update: new theory of function updates:
  2136     f(a:=b) == %x. if x=a then b else f x
  2137 may also be iterated as in f(a:=b,c:=d,...);
  2138 
  2139 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2140 
  2141 * HOL/List:
  2142   - new function list_update written xs[i:=v] that updates the i-th
  2143     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2144   - new function `upt' written [i..j(] which generates the list
  2145     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2146     bound write [i..j], which is a shorthand for [i..j+1(].
  2147   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2148 
  2149 * HOL/Arith:
  2150   - removed 'pred' (predecessor) function;
  2151   - generalized some theorems about n-1;
  2152   - many new laws about "div" and "mod";
  2153   - new laws about greatest common divisors (see theory ex/Primes);
  2154 
  2155 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2156 instead of "inverse";
  2157 
  2158 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2159   of the multiset ordering;
  2160 
  2161 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2162   (not included by default);
  2163 
  2164 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2165 
  2166 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2167   programs, i.e. different program variables may have different types.
  2168 
  2169 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2170   [previously, this check worked only if the rewrite rule was unconditional]
  2171   Now rew can involve either definitions or equalities (either == or =).
  2172 
  2173 
  2174 *** ZF ***
  2175 
  2176 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2177   only the theorems proved on ZF.ML;
  2178 
  2179 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2180   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2181   disjointness reasoning but breaking a few old proofs.
  2182 
  2183 * ZF/Update: new theory of function updates
  2184     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2185   may also be iterated as in f(a:=b,c:=d,...);
  2186 
  2187 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2188 
  2189 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2190   [previously, this check worked only if the rewrite rule was unconditional]
  2191   Now rew can involve either definitions or equalities (either == or =).
  2192 
  2193 * case_tac provided for compatibility with HOL
  2194     (like the old excluded_middle_tac, but with subgoals swapped)
  2195 
  2196 
  2197 *** Internal programming interfaces ***
  2198 
  2199 * Pure: several new basic modules made available for general use, see
  2200 also src/Pure/README;
  2201 
  2202 * improved the theory data mechanism to support encapsulation (data
  2203 kind name replaced by private Object.kind, acting as authorization
  2204 key); new type-safe user interface via functor TheoryDataFun; generic
  2205 print_data function becomes basically useless;
  2206 
  2207 * removed global_names compatibility flag -- all theory declarations
  2208 are qualified by default;
  2209 
  2210 * module Pure/Syntax now offers quote / antiquote translation
  2211 functions (useful for Hoare logic etc. with implicit dependencies);
  2212 see HOL/ex/Antiquote for an example use;
  2213 
  2214 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2215 cterm -> thm;
  2216 
  2217 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2218 subgoal;
  2219 
  2220 * Display.print_goals function moved to Locale.print_goals;
  2221 
  2222 * standard print function for goals supports current_goals_markers
  2223 variable for marking begin of proof, end of proof, start of goal; the
  2224 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2225 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2226 for example;
  2227 
  2228 
  2229 
  2230 New in Isabelle98 (January 1998)
  2231 --------------------------------
  2232 
  2233 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2234 
  2235 * changed lexical syntax of terms / types: dots made part of long
  2236 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2237 
  2238 * simpset (and claset) reference variable replaced by functions
  2239 simpset / simpset_ref;
  2240 
  2241 * no longer supports theory aliases (via merge) and non-trivial
  2242 implicit merge of thms' signatures;
  2243 
  2244 * most internal names of constants changed due to qualified names;
  2245 
  2246 * changed Pure/Sequence interface (see Pure/seq.ML);
  2247 
  2248 
  2249 *** General Changes ***
  2250 
  2251 * hierachically structured name spaces (for consts, types, axms, thms
  2252 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2253 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2254 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2255 long_names for fully qualified output names; NOTE: ML programs
  2256 (special tactics, packages etc.) referring to internal names may have
  2257 to be adapted to cope with fully qualified names; in case of severe
  2258 backward campatibility problems try setting 'global_names' at compile
  2259 time to have enrything declared within a flat name space; one may also
  2260 fine tune name declarations in theories via the 'global' and 'local'
  2261 section;
  2262 
  2263 * reimplemented the implicit simpset and claset using the new anytype
  2264 data filed in signatures; references simpset:simpset ref etc. are
  2265 replaced by functions simpset:unit->simpset and
  2266 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2267 to patch your ML files accordingly;
  2268 
  2269 * HTML output now includes theory graph data for display with Java
  2270 applet or isatool browser; data generated automatically via isatool
  2271 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2272 
  2273 * defs may now be conditional; improved rewrite_goals_tac to handle
  2274 conditional equations;
  2275 
  2276 * defs now admits additional type arguments, using TYPE('a) syntax;
  2277 
  2278 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2279 creates a new theory node; implicit merge of thms' signatures is
  2280 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2281 transfer:theory->thm->thm in (rare) cases;
  2282 
  2283 * improved handling of draft signatures / theories; draft thms (and
  2284 ctyps, cterms) are automatically promoted to real ones;
  2285 
  2286 * slightly changed interfaces for oracles: admit many per theory, named
  2287 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2288 
  2289 * print_goals: optional output of const types (set show_consts and
  2290 show_types);
  2291 
  2292 * improved output of warnings (###) and errors (***);
  2293 
  2294 * subgoal_tac displays a warning if the new subgoal has type variables;
  2295 
  2296 * removed old README and Makefiles;
  2297 
  2298 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2299 
  2300 * removed obsolete init_pps and init_database;
  2301 
  2302 * deleted the obsolete tactical STATE, which was declared by
  2303     fun STATE tacfun st = tacfun st st;
  2304 
  2305 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2306 (which abbreviates $HOME);
  2307 
  2308 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2309 use isatool fixseq to adapt your ML programs (this works for fully
  2310 qualified references to the Sequence structure only!);
  2311 
  2312 * use_thy no longer requires writable current directory; it always
  2313 reloads .ML *and* .thy file, if either one is out of date;
  2314 
  2315 
  2316 *** Classical Reasoner ***
  2317 
  2318 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2319 tactics that use classical reasoning to simplify a subgoal without
  2320 splitting it into several subgoals;
  2321 
  2322 * Safe_tac: like safe_tac but uses the default claset;
  2323 
  2324 
  2325 *** Simplifier ***
  2326 
  2327 * added simplification meta rules:
  2328     (asm_)(full_)simplify: simpset -> thm -> thm;
  2329 
  2330 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2331 logics (again);
  2332 
  2333 * added prems argument to simplification procedures;
  2334 
  2335 * HOL, FOL, ZF: added infix function `addsplits':
  2336   instead of `<simpset> setloop (split_tac <thms>)'
  2337   you can simply write `<simpset> addsplits <thms>'
  2338 
  2339 
  2340 *** Syntax ***
  2341 
  2342 * TYPE('a) syntax for type reflection terms;
  2343 
  2344 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2345 
  2346 * pretty printer: changed order of mixfix annotation preference (again!);
  2347 
  2348 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2349 
  2350 
  2351 *** HOL ***
  2352 
  2353 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2354   with `addloop' of the simplifier to faciliate case splitting in premises.
  2355 
  2356 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2357 
  2358 * HOL/Auth: new protocol proofs including some for the Internet
  2359   protocol TLS;
  2360 
  2361 * HOL/Map: new theory of `maps' a la VDM;
  2362 
  2363 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2364 cancelling out common nat summands from =, <, <= (in)equalities, or
  2365 differences; simplification procedures nat_cancel_factor for
  2366 cancelling common factor from =, <, <= (in)equalities over natural
  2367 sums; nat_cancel contains both kinds of procedures, it is installed by
  2368 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2369 
  2370 * HOL/simplifier: terms of the form
  2371   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2372   are rewritten to
  2373   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2374   and those of the form
  2375   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2376   are rewritten to
  2377   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2378 
  2379 * HOL/datatype
  2380   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2381 
  2382   P(t_case f1 ... fn x) =
  2383      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2384         ...
  2385        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2386      )
  2387 
  2388   and a theorem `split_t_case_asm' of the form
  2389 
  2390   P(t_case f1 ... fn x) =
  2391     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2392         ...
  2393        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2394      )
  2395   which can be added to a simpset via `addsplits'. The existing theorems
  2396   expand_list_case and expand_option_case have been renamed to
  2397   split_list_case and split_option_case.
  2398 
  2399 * HOL/Arithmetic:
  2400   - `pred n' is automatically converted to `n-1'.
  2401     Users are strongly encouraged not to use `pred' any longer,
  2402     because it will disappear altogether at some point.
  2403   - Users are strongly encouraged to write "0 < n" rather than
  2404     "n ~= 0". Theorems and proof tools have been modified towards this
  2405     `standard'.
  2406 
  2407 * HOL/Lists:
  2408   the function "set_of_list" has been renamed "set" (and its theorems too);
  2409   the function "nth" now takes its arguments in the reverse order and
  2410   has acquired the infix notation "!" as in "xs!n".
  2411 
  2412 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2413 
  2414 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2415   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2416 
  2417 * HOL/record: extensible records with schematic structural subtyping
  2418 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2419 still lacks various theorems and concrete record syntax;
  2420 
  2421 
  2422 *** HOLCF ***
  2423 
  2424 * removed "axioms" and "generated by" sections;
  2425 
  2426 * replaced "ops" section by extended "consts" section, which is capable of
  2427   handling the continuous function space "->" directly;
  2428 
  2429 * domain package:
  2430   . proves theorems immediately and stores them in the theory,
  2431   . creates hierachical name space,
  2432   . now uses normal mixfix annotations (instead of cinfix...),
  2433   . minor changes to some names and values (for consistency),
  2434   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2435   . separator between mutual domain defs: changed "," to "and",
  2436   . improved handling of sort constraints;  now they have to
  2437     appear on the left-hand side of the equations only;
  2438 
  2439 * fixed LAM <x,y,zs>.b syntax;
  2440 
  2441 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2442 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2443 
  2444 
  2445 *** FOL and ZF ***
  2446 
  2447 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2448   with `addloop' of the simplifier to faciliate case splitting in premises.
  2449 
  2450 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2451 in HOL, they strip ALL and --> from proved theorems;
  2452 
  2453 
  2454 
  2455 New in Isabelle94-8 (May 1997)
  2456 ------------------------------
  2457 
  2458 *** General Changes ***
  2459 
  2460 * new utilities to build / run / maintain Isabelle etc. (in parts
  2461 still somewhat experimental); old Makefiles etc. still functional;
  2462 
  2463 * new 'Isabelle System Manual';
  2464 
  2465 * INSTALL text, together with ./configure and ./build scripts;
  2466 
  2467 * reimplemented type inference for greater efficiency, better error
  2468 messages and clean internal interface;
  2469 
  2470 * prlim command for dealing with lots of subgoals (an easier way of
  2471 setting goals_limit);
  2472 
  2473 
  2474 *** Syntax ***
  2475 
  2476 * supports alternative (named) syntax tables (parser and pretty
  2477 printer); internal interface is provided by add_modesyntax(_i);
  2478 
  2479 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2480 be used in conjunction with the Isabelle symbol font; uses the
  2481 "symbols" syntax table;
  2482 
  2483 * added token_translation interface (may translate name tokens in
  2484 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2485 the current print_mode); IMPORTANT: user print translation functions
  2486 are responsible for marking newly introduced bounds
  2487 (Syntax.mark_boundT);
  2488 
  2489 * token translations for modes "xterm" and "xterm_color" that display
  2490 names in bold, underline etc. or colors (which requires a color
  2491 version of xterm);
  2492 
  2493 * infixes may now be declared with names independent of their syntax;
  2494 
  2495 * added typed_print_translation (like print_translation, but may
  2496 access type of constant);
  2497 
  2498 
  2499 *** Classical Reasoner ***
  2500 
  2501 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2502 some limitations.  Blast_tac...
  2503   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2504   + ignores elimination rules that don't have the correct format
  2505         (the conclusion MUST be a formula variable)
  2506   + ignores types, which can make HOL proofs fail
  2507   + rules must not require higher-order unification, e.g. apply_type in ZF
  2508     [message "Function Var's argument not a bound variable" relates to this]
  2509   + its proof strategy is more general but can actually be slower
  2510 
  2511 * substitution with equality assumptions no longer permutes other
  2512 assumptions;
  2513 
  2514 * minor changes in semantics of addafter (now called addaltern); renamed
  2515 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2516 (and access functions for it);
  2517 
  2518 * improved combination of classical reasoner and simplifier:
  2519   + functions for handling clasimpsets
  2520   + improvement of addss: now the simplifier is called _after_ the
  2521     safe steps.
  2522   + safe variant of addss called addSss: uses safe simplifications
  2523     _during_ the safe steps. It is more complete as it allows multiple
  2524     instantiations of unknowns (e.g. with slow_tac).
  2525 
  2526 *** Simplifier ***
  2527 
  2528 * added interface for simplification procedures (functions that
  2529 produce *proven* rewrite rules on the fly, depending on current
  2530 redex);
  2531 
  2532 * ordering on terms as parameter (used for ordered rewriting);
  2533 
  2534 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2535 
  2536 * the solver is now split into a safe and an unsafe part.
  2537 This should be invisible for the normal user, except that the
  2538 functions setsolver and addsolver have been renamed to setSolver and
  2539 addSolver; added safe_asm_full_simp_tac;
  2540 
  2541 
  2542 *** HOL ***
  2543 
  2544 * a generic induction tactic `induct_tac' which works for all datatypes and
  2545 also for type `nat';
  2546 
  2547 * a generic case distinction tactic `exhaust_tac' which works for all
  2548 datatypes and also for type `nat';
  2549 
  2550 * each datatype comes with a function `size';
  2551 
  2552 * patterns in case expressions allow tuple patterns as arguments to
  2553 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2554 
  2555 * primrec now also works with type nat;
  2556 
  2557 * recdef: a new declaration form, allows general recursive functions to be
  2558 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2559 
  2560 * the constant for negation has been renamed from "not" to "Not" to
  2561 harmonize with FOL, ZF, LK, etc.;
  2562 
  2563 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2564 infinite lists;
  2565 
  2566 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2567 
  2568 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2569 problems in commutative rings, using axiomatic type classes for + and *;
  2570 
  2571 * more examples in HOL/MiniML and HOL/Auth;
  2572 
  2573 * more default rewrite rules for quantifiers, union/intersection;
  2574 
  2575 * a new constant `arbitrary == @x.False';
  2576 
  2577 * HOLCF/IOA replaces old HOL/IOA;
  2578 
  2579 * HOLCF changes: derived all rules and arities
  2580   + axiomatic type classes instead of classes
  2581   + typedef instead of faking type definitions
  2582   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2583   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2584   + eliminated the types void, one, tr
  2585   + use unit lift and bool lift (with translations) instead of one and tr
  2586   + eliminated blift from Lift3.thy (use Def instead of blift)
  2587   all eliminated rules are derived as theorems --> no visible changes ;
  2588 
  2589 
  2590 *** ZF ***
  2591 
  2592 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2593 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2594 as ZF_cs addSIs [equalityI];
  2595 
  2596 
  2597 
  2598 New in Isabelle94-7 (November 96)
  2599 ---------------------------------
  2600 
  2601 * allowing negative levels (as offsets) in prlev and choplev;
  2602 
  2603 * super-linear speedup for large simplifications;
  2604 
  2605 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2606 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2607 FAIL); can suppress it using the command Delsimps (ex_simps @
  2608 all_simps); De Morgan laws are also now included, by default;
  2609 
  2610 * improved printing of ==>  :  ~:
  2611 
  2612 * new object-logic "Sequents" adds linear logic, while replacing LK
  2613 and Modal (thanks to Sara Kalvala);
  2614 
  2615 * HOL/Auth: correctness proofs for authentication protocols;
  2616 
  2617 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2618 examples on HOL/Auth);
  2619 
  2620 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2621 the rewriter and classical reasoner simultaneously;
  2622 
  2623 * function uresult no longer returns theorems in "standard" format;
  2624 regain previous version by: val uresult = standard o uresult;
  2625 
  2626 
  2627 
  2628 New in Isabelle94-6
  2629 -------------------
  2630 
  2631 * oracles -- these establish an interface between Isabelle and trusted
  2632 external reasoners, which may deliver results as theorems;
  2633 
  2634 * proof objects (in particular record all uses of oracles);
  2635 
  2636 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2637 
  2638 * "constdefs" section in theory files;
  2639 
  2640 * "primrec" section (HOL) no longer requires names;
  2641 
  2642 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2643 
  2644 
  2645 
  2646 New in Isabelle94-5
  2647 -------------------
  2648 
  2649 * reduced space requirements;
  2650 
  2651 * automatic HTML generation from theories;
  2652 
  2653 * theory files no longer require "..." (quotes) around most types;
  2654 
  2655 * new examples, including two proofs of the Church-Rosser theorem;
  2656 
  2657 * non-curried (1994) version of HOL is no longer distributed;
  2658 
  2659 
  2660 
  2661 New in Isabelle94-4
  2662 -------------------
  2663 
  2664 * greatly reduced space requirements;
  2665 
  2666 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2667 
  2668 * searchable theorem database (see the section "Retrieving theorems" on
  2669 page 8 of the Reference Manual);
  2670 
  2671 * new examples, including Grabczewski's monumental case study of the
  2672 Axiom of Choice;
  2673 
  2674 * The previous version of HOL renamed to Old_HOL;
  2675 
  2676 * The new version of HOL (previously called CHOL) uses a curried syntax
  2677 for functions.  Application looks like f a b instead of f(a,b);
  2678 
  2679 * Mutually recursive inductive definitions finally work in HOL;
  2680 
  2681 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2682 translates to the operator "split";
  2683 
  2684 
  2685 
  2686 New in Isabelle94-3
  2687 -------------------
  2688 
  2689 * new infix operator, addss, allowing the classical reasoner to
  2690 perform simplification at each step of its search.  Example:
  2691         fast_tac (cs addss ss)
  2692 
  2693 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2694 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2695 look like (a,b) instead of <a,b>;
  2696 
  2697 * PLEASE NOTE: CHOL will eventually replace HOL!
  2698 
  2699 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2700 It translates to the operator "split".  A new theory of integers is available;
  2701 
  2702 * In ZF, integer numerals now denote two's-complement binary integers.
  2703 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2704 
  2705 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2706 of the Axiom of Choice;
  2707 
  2708 
  2709 
  2710 New in Isabelle94-2
  2711 -------------------
  2712 
  2713 * Significantly faster resolution;
  2714 
  2715 * the different sections in a .thy file can now be mixed and repeated
  2716 freely;
  2717 
  2718 * Database of theorems for FOL, HOL and ZF.  New
  2719 commands including qed, qed_goal and bind_thm store theorems in the database.
  2720 
  2721 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2722 a given theory (thms_of), or find out what theory a theorem was proved in
  2723 (theory_of_thm);
  2724 
  2725 * Bugs fixed in the inductive definition and datatype packages;
  2726 
  2727 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2728 and HOL_dup_cs obsolete;
  2729 
  2730 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2731 have been removed;
  2732 
  2733 * Simpler definition of function space in ZF;
  2734 
  2735 * new results about cardinal and ordinal arithmetic in ZF;
  2736 
  2737 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2738 types;
  2739 
  2740 
  2741 $Id$