NEWS
author wenzelm
Sun Jun 13 15:30:08 2004 +0200 (2004-06-13)
changeset 14934 bf9f525d4821
parent 14919 0f5fde03e2b5
child 14972 51f95648abad
permissions -rw-r--r--
added display_drafts and print_drafts commands;
     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.
    79 
    80 
    81 *** HOL ***
    82 
    83 * HOL/record: reimplementation of records. Improved scalability for
    84   records with many fields, avoiding performance problems for type
    85   inference. Records are no longer composed of nested field types, but
    86   of nested extension types. Therefore the record type only grows
    87   linear in the number of extensions and not in the number of fields.
    88   The top-level (users) view on records is preserved.  Potential
    89   INCOMPATIBILITY only in strange cases, where the theory depends on
    90   the old record representation. The type generated for a record is
    91   called <record_name>_ext_type.
    92 
    93 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
    94 
    95   syntax (epsilon)
    96     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
    97 
    98   The symbol \<some> is displayed as the alternative epsilon of LaTeX
    99   and x-symbol; use option '-m epsilon' to get it actually printed.
   100   Moreover, the mathematically important symbolic identifier
   101   \<epsilon> becomes available as variable, constant etc.
   102 
   103 * Simplifier: "record_upd_simproc" for simplification of multiple
   104   record updates enabled by default.  INCOMPATIBILITY: old proofs
   105   break occasionally, since simplification is more powerful by
   106   default.
   107 
   108 
   109 *** HOLCF ***
   110 
   111 * HOLCF: discontinued special version of 'constdefs' (which used to
   112   support continuous functions) in favor of the general Pure one with
   113   full type-inference.
   114 
   115 
   116 *** ZF ***
   117 
   118 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the First
   119   Isomorphism Theorem (on quotienting by the kernel of a homomorphism).
   120 
   121 
   122 
   123 New in Isabelle2004 (April 2004)
   124 --------------------------------
   125 
   126 *** General ***
   127 
   128 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   129   Replaces linorder.ML.
   130 
   131 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   132   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   133   (\<a>...\<z>), are now considered normal letters, and can therefore
   134   be used anywhere where an ASCII letter (a...zA...Z) has until
   135   now. COMPATIBILITY: This obviously changes the parsing of some
   136   terms, especially where a symbol has been used as a binder, say
   137   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   138   as an identifier.  Fix it by inserting a space around former
   139   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   140   existing theory and ML files.
   141 
   142 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   143 
   144 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   145   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   146   a normal (but invisible) letter. For multiple letter subscripts repeat
   147   \<^isub> like this: x\<^isub>1\<^isub>2.
   148 
   149 * Pure: There are now sub-/superscripts that can span more than one
   150   character. Text between \<^bsub> and \<^esub> is set in subscript in
   151   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   152   superscript. The new control characters are not identifier parts.
   153 
   154 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   155   content of "..." to the latex file instead of \isacntrl... . The "..."
   156   may consist of any printable characters excluding the end bracket >.
   157 
   158 * Pure: Using new Isar command "finalconsts" (or the ML functions
   159   Theory.add_finals or Theory.add_finals_i) it is now possible to
   160   declare constants "final", which prevents their being given a definition
   161   later.  It is useful for constants whose behaviour is fixed axiomatically
   162   rather than definitionally, such as the meta-logic connectives.
   163 
   164 * Pure: 'instance' now handles general arities with general sorts
   165   (i.e. intersections of classes),
   166 
   167 * Presentation: generated HTML now uses a CSS style sheet to make layout
   168   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   169   It can be changed to alter the colors/layout of generated pages.
   170 
   171 
   172 *** Isar ***
   173 
   174 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   175   cut_tac, subgoal_tac and thin_tac:
   176   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   177     locales are no longer forced to write Isar proof scripts.
   178     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   179     emulations.
   180   - INCOMPATIBILITY: names of variables to be instantiated may no
   181     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   182     This is consistent with the instantiation attribute "where".
   183 
   184 * Attributes "where" and "of":
   185   - Now take type variables of instantiated theorem into account when reading
   186     the instantiation string.  This fixes a bug that caused instantiated
   187     theorems to have too special types in some circumstances.
   188   - "where" permits explicit instantiations of type variables.
   189 
   190 * Calculation commands "moreover" and "also" no longer interfere with
   191   current facts ("this"), admitting arbitrary combinations with "then"
   192   and derived forms.
   193 
   194 * Locales:
   195   - Goal statements involving the context element "includes" no longer
   196     generate theorems with internal delta predicates (those ending on
   197     "_axioms") in the premise.
   198     Resolve particular premise with <locale>.intro to obtain old form.
   199   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   200     specification and "includes" elements in goal statement.
   201   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   202     [intro?] and [elim?] (respectively) by default.
   203   - Experimental command for instantiation of locales in proof contexts:
   204         instantiate <label>[<attrs>]: <loc>
   205     Instantiates locale <loc> and adds all its theorems to the current context
   206     taking into account their attributes.  Label and attrs are optional
   207     modifiers, like in theorem declarations.  If present, names of
   208     instantiated theorems are qualified with <label>, and the attributes
   209     <attrs> are applied after any attributes these theorems might have already.
   210       If the locale has assumptions, a chained fact of the form
   211     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   212     are derived.  The command does not support old-style locales declared
   213     with "locale (open)".
   214       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   215 
   216 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   217   (Isar) contexts.
   218 
   219 
   220 *** HOL ***
   221 
   222 * Proof import: new image HOL4 contains the imported library from
   223   the HOL4 system with about 2500 theorems. It is imported by
   224   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   225   can be used like any other Isabelle image.  See
   226   HOL/Import/HOL/README for more information.
   227 
   228 * Simplifier:
   229   - Much improved handling of linear and partial orders.
   230     Reasoners for linear and partial orders are set up for type classes
   231     "linorder" and "order" respectively, and are added to the default simpset
   232     as solvers.  This means that the simplifier can build transitivity chains
   233     to solve goals from the assumptions.
   234   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   235     of blast or auto after simplification become unnecessary because the goal
   236     is solved by simplification already.
   237 
   238 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   239     all proved in axiomatic type classes for semirings, rings and fields.
   240 
   241 * Numerics:
   242   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   243     now formalized using the Ring_and_Field theory mentioned above.
   244   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   245     than before, because now they are set up once in a generic manner.
   246   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   247     Look for the general versions in Ring_and_Field (and Power if they concern
   248     exponentiation).
   249 
   250 * Type "rat" of the rational numbers is now available in HOL-Complex.
   251 
   252 * Records:
   253   - Record types are now by default printed with their type abbreviation
   254     instead of the list of all field types. This can be configured via
   255     the reference "print_record_type_abbr".
   256   - Simproc "record_upd_simproc" for simplification of multiple updates added
   257     (not enabled by default).
   258   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   259     EX x. x = sel r to True (not enabled by default).
   260   - Tactic "record_split_simp_tac" to split and simplify records added.
   261 
   262 * 'specification' command added, allowing for definition by
   263   specification.  There is also an 'ax_specification' command that
   264   introduces the new constants axiomatically.
   265 
   266 * arith(_tac) is now able to generate counterexamples for reals as well.
   267 
   268 * HOL-Algebra: new locale "ring" for non-commutative rings.
   269 
   270 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   271   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   272 
   273 * HOL-Matrix: a first theory for matrices in HOL with an application of
   274   matrix theory to linear programming.
   275 
   276 * Unions and Intersections:
   277   The x-symbol output syntax of UN and INT has been changed
   278   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   279   i.e. the index formulae has become a subscript, like in normal math.
   280   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   281   The subscript version is also accepted as input syntax.
   282 
   283 * Unions and Intersections over Intervals:
   284   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   285   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   286   like in normal math, and corresponding versions for < and for intersection.
   287 
   288 * ML: the legacy theory structures Int and List have been removed. They had
   289   conflicted with ML Basis Library structures having the same names.
   290 
   291 * 'refute' command added to search for (finite) countermodels.  Only works
   292   for a fragment of HOL.  The installation of an external SAT solver is
   293   highly recommended.  See "HOL/Refute.thy" for details.
   294 
   295 * 'quickcheck' command: Allows to find counterexamples by evaluating
   296   formulae under an assignment of free variables to random values.
   297   In contrast to 'refute', it can deal with inductive datatypes,
   298   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   299   for examples.
   300 
   301 
   302 *** HOLCF ***
   303 
   304 * Streams now come with concatenation and are part of the HOLCF image
   305 
   306 
   307 
   308 New in Isabelle2003 (May 2003)
   309 ------------------------------
   310 
   311 *** General ***
   312 
   313 * Provers/simplifier:
   314 
   315   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   316     Assumptions are now subject to complete mutual simplification,
   317     not just from left to right. The simplifier now preserves
   318     the order of assumptions.
   319 
   320     Potential INCOMPATIBILITY:
   321 
   322     -- simp sometimes diverges where the old version did
   323        not, e.g. invoking simp on the goal
   324 
   325         [| P (f x); y = x; f x = f y |] ==> Q
   326 
   327        now gives rise to the infinite reduction sequence
   328 
   329         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   330 
   331        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   332        kind of problem.
   333 
   334     -- Tactics combining classical reasoner and simplification (such as auto)
   335        are also affected by this change, because many of them rely on
   336        simp. They may sometimes diverge as well or yield a different numbers
   337        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   338        in case of problems. Sometimes subsequent calls to the classical
   339        reasoner will fail because a preceeding call to the simplifier too
   340        eagerly simplified the goal, e.g. deleted redundant premises.
   341 
   342   - The simplifier trace now shows the names of the applied rewrite rules
   343 
   344   - You can limit the number of recursive invocations of the simplifier
   345     during conditional rewriting (where the simplifie tries to solve the
   346     conditions before applying the rewrite rule):
   347     ML "simp_depth_limit := n"
   348     where n is an integer. Thus you can force termination where previously
   349     the simplifier would diverge.
   350 
   351   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   352 
   353   - No longer aborts on failed congruence proof.  Instead, the
   354     congruence is ignored.
   355 
   356 * Pure: New generic framework for extracting programs from constructive
   357   proofs. See HOL/Extraction.thy for an example instantiation, as well
   358   as HOL/Extraction for some case studies.
   359 
   360 * Pure: The main goal of the proof state is no longer shown by default, only
   361 the subgoals. This behaviour is controlled by a new flag.
   362    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   363 (ML: Proof.show_main_goal).
   364 
   365 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   366 rules whose conclusion matches subgoal 1:
   367       PG menu: Isabelle/Isar -> Show me -> matching rules
   368 The rules are ordered by how closely they match the subgoal.
   369 In particular, rules that solve a subgoal outright are displayed first
   370 (or rather last, the way they are printed).
   371 (ML: ProofGeneral.print_intros())
   372 
   373 * Pure: New flag trace_unify_fail causes unification to print
   374 diagnostic information (PG: in trace buffer) when it fails. This is
   375 useful for figuring out why single step proofs like rule, erule or
   376 assumption failed.
   377 
   378 * Pure: Locale specifications now produce predicate definitions
   379 according to the body of text (covering assumptions modulo local
   380 definitions); predicate "loc_axioms" covers newly introduced text,
   381 while "loc" is cumulative wrt. all included locale expressions; the
   382 latter view is presented only on export into the global theory
   383 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   384 on the old view without predicates;
   385 
   386 * Pure: predefined locales "var" and "struct" are useful for sharing
   387 parameters (as in CASL, for example); just specify something like
   388 ``var x + var y + struct M'' as import;
   389 
   390 * Pure: improved thms_containing: proper indexing of facts instead of
   391 raw theorems; check validity of results wrt. current name space;
   392 include local facts of proof configuration (also covers active
   393 locales), cover fixed variables in index; may use "_" in term
   394 specification; an optional limit for the number of printed facts may
   395 be given (the default is 40);
   396 
   397 * Pure: disallow duplicate fact bindings within new-style theory files
   398 (batch-mode only);
   399 
   400 * Provers: improved induct method: assumptions introduced by case
   401 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   402 the goal statement); "foo" still refers to all facts collectively;
   403 
   404 * Provers: the function blast.overloaded has been removed: all constants
   405 are regarded as potentially overloaded, which improves robustness in exchange
   406 for slight decrease in efficiency;
   407 
   408 * Provers/linorder: New generic prover for transitivity reasoning over
   409 linear orders.  Note: this prover is not efficient!
   410 
   411 * Isar: preview of problems to finish 'show' now produce an error
   412 rather than just a warning (in interactive mode);
   413 
   414 
   415 *** HOL ***
   416 
   417 * arith(_tac)
   418 
   419  - Produces a counter example if it cannot prove a goal.
   420    Note that the counter example may be spurious if the goal is not a formula
   421    of quantifier-free linear arithmetic.
   422    In ProofGeneral the counter example appears in the trace buffer.
   423 
   424  - Knows about div k and mod k where k is a numeral of type nat or int.
   425 
   426  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   427    linear arithmetic fails. This takes account of quantifiers and divisibility.
   428    Presburger arithmetic can also be called explicitly via presburger(_tac).
   429 
   430 * simp's arithmetic capabilities have been enhanced a bit: it now
   431 takes ~= in premises into account (by performing a case split);
   432 
   433 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   434 are distributed over a sum of terms;
   435 
   436 * New tactic "trans_tac" and method "trans" instantiate
   437 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   438 "<=", "<" and "=").
   439 
   440 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   441 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   442 
   443 * 'typedef' command has new option "open" to suppress the set
   444 definition;
   445 
   446 * functions Min and Max on finite sets have been introduced (theory
   447 Finite_Set);
   448 
   449 * attribute [symmetric] now works for relations as well; it turns
   450 (x,y) : R^-1 into (y,x) : R, and vice versa;
   451 
   452 * induct over a !!-quantified statement (say !!x1..xn):
   453   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   454 
   455 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   456 %x. None. Warning: empty_def now refers to the previously hidden definition
   457 of the empty set.
   458 
   459 * Algebra: formalization of classical algebra.  Intended as base for
   460 any algebraic development in Isabelle.  Currently covers group theory
   461 (up to Sylow's theorem) and ring theory (Universal Property of
   462 Univariate Polynomials).  Contributions welcome;
   463 
   464 * GroupTheory: deleted, since its material has been moved to Algebra;
   465 
   466 * Complex: new directory of the complex numbers with numeric constants,
   467 nonstandard complex numbers, and some complex analysis, standard and
   468 nonstandard (Jacques Fleuriot);
   469 
   470 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   471 
   472 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   473 Fleuriot);
   474 
   475 * Real/HahnBanach: updated and adapted to locales;
   476 
   477 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   478 Gray and Kramer);
   479 
   480 * UNITY: added the Meier-Sanders theory of progress sets;
   481 
   482 * MicroJava: bytecode verifier and lightweight bytecode verifier
   483 as abstract algorithms, instantiated to the JVM;
   484 
   485 * Bali: Java source language formalization. Type system, operational
   486 semantics, axiomatic semantics. Supported language features:
   487 classes, interfaces, objects,virtual methods, static methods,
   488 static/instance fields, arrays, access modifiers, definite
   489 assignment, exceptions.
   490 
   491 
   492 *** ZF ***
   493 
   494 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   495 universe, etc.);
   496 
   497 * Main ZF: virtually all theories converted to new-style format;
   498 
   499 
   500 *** ML ***
   501 
   502 * Pure: Tactic.prove provides sane interface for internal proofs;
   503 omits the infamous "standard" operation, so this is more appropriate
   504 than prove_goalw_cterm in many situations (e.g. in simprocs);
   505 
   506 * Pure: improved error reporting of simprocs;
   507 
   508 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   509 up simprocs;
   510 
   511 
   512 *** Document preparation ***
   513 
   514 * uses \par instead of \\ for line breaks in theory text. This may
   515 shift some page breaks in large documents. To get the old behaviour
   516 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   517 
   518 * minimized dependencies of isabelle.sty and isabellesym.sty on
   519 other packages
   520 
   521 * \<euro> now needs package babel/greek instead of marvosym (which
   522 broke \Rightarrow)
   523 
   524 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   525 textcomp package)
   526 
   527 
   528 
   529 New in Isabelle2002 (March 2002)
   530 --------------------------------
   531 
   532 *** Document preparation ***
   533 
   534 * greatly simplified document preparation setup, including more
   535 graceful interpretation of isatool usedir -i/-d/-D options, and more
   536 instructive isatool mkdir; users should basically be able to get
   537 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   538 users may run a separate document processing stage manually like this:
   539 "isatool usedir -D output HOL Test && isatool document Test/output";
   540 
   541 * theory dependency graph may now be incorporated into documents;
   542 isatool usedir -g true will produce session_graph.eps/.pdf for use
   543 with \includegraphics of LaTeX;
   544 
   545 * proper spacing of consecutive markup elements, especially text
   546 blocks after section headings;
   547 
   548 * support bold style (for single symbols only), input syntax is like
   549 this: "\<^bold>\<alpha>" or "\<^bold>A";
   550 
   551 * \<bullet> is now output as bold \cdot by default, which looks much
   552 better in printed text;
   553 
   554 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   555 note that these symbols are currently unavailable in Proof General /
   556 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   557 
   558 * isatool latex no longer depends on changed TEXINPUTS, instead
   559 isatool document copies the Isabelle style files to the target
   560 location;
   561 
   562 
   563 *** Isar ***
   564 
   565 * Pure/Provers: improved proof by cases and induction;
   566   - 'case' command admits impromptu naming of parameters (such as
   567     "case (Suc n)");
   568   - 'induct' method divinates rule instantiation from the inductive
   569     claim; no longer requires excessive ?P bindings for proper
   570     instantiation of cases;
   571   - 'induct' method properly enumerates all possibilities of set/type
   572     rules; as a consequence facts may be also passed through *type*
   573     rules without further ado;
   574   - 'induct' method now derives symbolic cases from the *rulified*
   575     rule (before it used to rulify cases stemming from the internal
   576     atomized version); this means that the context of a non-atomic
   577     statement becomes is included in the hypothesis, avoiding the
   578     slightly cumbersome show "PROP ?case" form;
   579   - 'induct' may now use elim-style induction rules without chaining
   580     facts, using ``missing'' premises from the goal state; this allows
   581     rules stemming from inductive sets to be applied in unstructured
   582     scripts, while still benefitting from proper handling of non-atomic
   583     statements; NB: major inductive premises need to be put first, all
   584     the rest of the goal is passed through the induction;
   585   - 'induct' proper support for mutual induction involving non-atomic
   586     rule statements (uses the new concept of simultaneous goals, see
   587     below);
   588   - append all possible rule selections, but only use the first
   589     success (no backtracking);
   590   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   591   - undeclared rule case names default to numbers 1, 2, 3, ...;
   592   - added 'print_induct_rules' (covered by help item in recent Proof
   593     General versions);
   594   - moved induct/cases attributes to Pure, methods to Provers;
   595   - generic method setup instantiated for FOL and HOL;
   596 
   597 * Pure: support multiple simultaneous goal statements, for example
   598 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   599 meta-level mechanism, this acts as if several individual goals had
   600 been stated separately; in particular common proof methods need to be
   601 repeated in order to cover all claims; note that a single elimination
   602 step is *not* sufficient to establish the two conjunctions, so this
   603 fails:
   604 
   605   assume "A & B" then have A and B ..   (*".." fails*)
   606 
   607 better use "obtain" in situations as above; alternative refer to
   608 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   609 
   610 * Pure: proper integration with ``locales''; unlike the original
   611 version by Florian Kammüller, Isar locales package high-level proof
   612 contexts rather than raw logical ones (e.g. we admit to include
   613 attributes everywhere); operations on locales include merge and
   614 rename; support for implicit arguments (``structures''); simultaneous
   615 type-inference over imports and text; see also HOL/ex/Locales.thy for
   616 some examples;
   617 
   618 * Pure: the following commands have been ``localized'', supporting a
   619 target locale specification "(in name)": 'lemma', 'theorem',
   620 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   621 stored both within the locale and at the theory level (exported and
   622 qualified by the locale name);
   623 
   624 * Pure: theory goals may now be specified in ``long'' form, with
   625 ad-hoc contexts consisting of arbitrary locale elements. for example
   626 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   627 definitions may be given, too); the result is a meta-level rule with
   628 the context elements being discharged in the obvious way;
   629 
   630 * Pure: new proof command 'using' allows to augment currently used
   631 facts after a goal statement ('using' is syntactically analogous to
   632 'apply', but acts on the goal's facts only); this allows chained facts
   633 to be separated into parts given before and after a claim, as in
   634 ``from a and b have C using d and e <proof>'';
   635 
   636 * Pure: renamed "antecedent" case to "rule_context";
   637 
   638 * Pure: new 'judgment' command records explicit information about the
   639 object-logic embedding (used by several tools internally); no longer
   640 use hard-wired "Trueprop";
   641 
   642 * Pure: added 'corollary' command;
   643 
   644 * Pure: fixed 'token_translation' command;
   645 
   646 * Pure: removed obsolete 'exported' attribute;
   647 
   648 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   649 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   650 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   651 
   652 * Pure: method 'atomize' presents local goal premises as object-level
   653 statements (atomic meta-level propositions); setup controlled via
   654 rewrite rules declarations of 'atomize' attribute; example
   655 application: 'induct' method with proper rule statements in improper
   656 proof *scripts*;
   657 
   658 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   659 now consider the syntactic context of assumptions, giving a better
   660 chance to get type-inference of the arguments right (this is
   661 especially important for locales);
   662 
   663 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   664 mode;
   665 
   666 * Pure/obtain: the formal conclusion "thesis", being marked as
   667 ``internal'', may no longer be reference directly in the text;
   668 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   669 situations;
   670 
   671 * Pure: generic 'sym' attribute which declares a rule both as pure
   672 'elim?' and for the 'symmetric' operation;
   673 
   674 * Pure: marginal comments ``--'' may now occur just anywhere in the
   675 text; the fixed correlation with particular command syntax has been
   676 discontinued;
   677 
   678 * Pure: new method 'rules' is particularly well-suited for proof
   679 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   680 but often produces more compact proof terms with less detours;
   681 
   682 * Pure/Provers/classical: simplified integration with pure rule
   683 attributes and methods; the classical "intro?/elim?/dest?"
   684 declarations coincide with the pure ones; the "rule" method no longer
   685 includes classically swapped intros; "intro" and "elim" methods no
   686 longer pick rules from the context; also got rid of ML declarations
   687 AddXIs/AddXEs/AddXDs; all of this has some potential for
   688 INCOMPATIBILITY;
   689 
   690 * Provers/classical: attribute 'swapped' produces classical inversions
   691 of introduction rules;
   692 
   693 * Provers/simplifier: 'simplified' attribute may refer to explicit
   694 rules instead of full simplifier context; 'iff' attribute handles
   695 conditional rules;
   696 
   697 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   698 
   699 * HOL: 'recdef' now fails on unfinished automated proofs, use
   700 "(permissive)" option to recover old behavior;
   701 
   702 * HOL: 'inductive' no longer features separate (collective) attributes
   703 for 'intros' (was found too confusing);
   704 
   705 * HOL: properly declared induction rules less_induct and
   706 wf_induct_rule;
   707 
   708 
   709 *** HOL ***
   710 
   711 * HOL: moved over to sane numeral syntax; the new policy is as
   712 follows:
   713 
   714   - 0 and 1 are polymorphic constants, which are defined on any
   715   numeric type (nat, int, real etc.);
   716 
   717   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   718   binary representation internally;
   719 
   720   - type nat has special constructor Suc, and generally prefers Suc 0
   721   over 1::nat and Suc (Suc 0) over 2::nat;
   722 
   723 This change may cause significant problems of INCOMPATIBILITY; here
   724 are some hints on converting existing sources:
   725 
   726   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   727   entities, so expressions involving "-" (unary or binary minus) need
   728   to be spaced properly;
   729 
   730   - existing occurrences of "1" may need to be constraint "1::nat" or
   731   even replaced by Suc 0; similar for old "2";
   732 
   733   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   734 
   735   - remove all special provisions on numerals in proofs;
   736 
   737 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   738 representation (depends on bin_arith_simps in the default context);
   739 
   740 * HOL: symbolic syntax for x^2 (numeral 2);
   741 
   742 * HOL: the class of all HOL types is now called "type" rather than
   743 "term"; INCOMPATIBILITY, need to adapt references to this type class
   744 in axclass/classes, instance/arities, and (usually rare) occurrences
   745 in typings (of consts etc.); internally the class is called
   746 "HOL.type", ML programs should refer to HOLogic.typeS;
   747 
   748 * HOL/record package improvements:
   749   - new derived operations "fields" to build a partial record section,
   750     "extend" to promote a fixed record to a record scheme, and
   751     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   752     declared as simp by default;
   753   - shared operations ("more", "fields", etc.) now need to be always
   754     qualified) --- potential INCOMPATIBILITY;
   755   - removed "make_scheme" operations (use "make" with "extend") --
   756     INCOMPATIBILITY;
   757   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   758   - provides cases/induct rules for use with corresponding Isar
   759     methods (for concrete records, record schemes, concrete more
   760     parts, and schematic more parts -- in that order);
   761   - internal definitions directly based on a light-weight abstract
   762     theory of product types over typedef rather than datatype;
   763 
   764 * HOL: generic code generator for generating executable ML code from
   765 specifications; specific support for HOL constructs such as inductive
   766 datatypes and sets, as well as recursive functions; can be invoked
   767 via 'generate_code' theory section;
   768 
   769 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   770 
   771 * HOL: consolidated and renamed several theories.  In particular:
   772         Ord.thy has been absorbed into HOL.thy
   773         String.thy has been absorbed into List.thy
   774 
   775 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   776 (beware of argument permutation!);
   777 
   778 * HOL: linorder_less_split superseded by linorder_cases;
   779 
   780 * HOL/List: "nodups" renamed to "distinct";
   781 
   782 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   783 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   784   - Ex_def has changed, now need to use some_eq_ex
   785 
   786 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   787 in this (rare) case use:
   788 
   789   delSWrapper "split_all_tac"
   790   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   791 
   792 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   793 MAY FAIL;
   794 
   795 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   796 Isabelle's type classes, ^ on functions and relations has too general
   797 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   798 necessary to attach explicit type constraints;
   799 
   800 * HOL/Relation: the prefix name of the infix "O" has been changed from
   801 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   802 renamed accordingly (eg "compI" -> "rel_compI").
   803 
   804 * HOL: syntax translations now work properly with numerals and records
   805 expressions;
   806 
   807 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   808 of "lam" -- INCOMPATIBILITY;
   809 
   810 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   811 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   812 renamed "Product_Type.unit";
   813 
   814 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   815 
   816 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   817 the "cases" method);
   818 
   819 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   820 Florian Kammüller);
   821 
   822 * HOL/IMP: updated and converted to new-style theory format; several
   823 parts turned into readable document, with proper Isar proof texts and
   824 some explanations (by Gerwin Klein);
   825 
   826 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   827 
   828 * HOL-Hyperreal is now a logic image;
   829 
   830 
   831 *** HOLCF ***
   832 
   833 * Isar: consts/constdefs supports mixfix syntax for continuous
   834 operations;
   835 
   836 * Isar: domain package adapted to new-style theory format, e.g. see
   837 HOLCF/ex/Dnat.thy;
   838 
   839 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   840 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   841 lift.induct_tac, always use UU instead of Undef;
   842 
   843 * HOLCF/IMP: updated and converted to new-style theory;
   844 
   845 
   846 *** ZF ***
   847 
   848 * Isar: proper integration of logic-specific tools and packages,
   849 including theory commands '(co)inductive', '(co)datatype',
   850 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   851 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   852 
   853 * theory Main no longer includes AC; for the Axiom of Choice, base
   854 your theory on Main_ZFC;
   855 
   856 * the integer library now covers quotients and remainders, with many
   857 laws relating division to addition, multiplication, etc.;
   858 
   859 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   860 typeless version of the formalism;
   861 
   862 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   863 format;
   864 
   865 * ZF/Induct: new directory for examples of inductive definitions,
   866 including theory Multiset for multiset orderings; converted to
   867 new-style theory format;
   868 
   869 * ZF: many new theorems about lists, ordinals, etc.;
   870 
   871 
   872 *** General ***
   873 
   874 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   875 variable proof controls level of detail: 0 = no proofs (only oracle
   876 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   877 also ref manual for further ML interfaces;
   878 
   879 * Pure/axclass: removed obsolete ML interface
   880 goal_subclass/goal_arity;
   881 
   882 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   883 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   884 separate tokens, so expressions involving minus need to be spaced
   885 properly;
   886 
   887 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   888 rather than "infixl" or "infixr";
   889 
   890 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   891 sort constraint specifications in type inference; e.g. "x::_::foo"
   892 ensures that the type of "x" is of sort "foo" (but not necessarily a
   893 type variable);
   894 
   895 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   896 control output of nested => (types); the default behavior is
   897 "type_brackets";
   898 
   899 * Pure/syntax: builtin parse translation for "_constify" turns valued
   900 tokens into AST constants;
   901 
   902 * Pure/syntax: prefer later declarations of translations and print
   903 translation functions; potential INCOMPATIBILITY: need to reverse
   904 multiple declarations for same syntax element constant;
   905 
   906 * Pure/show_hyps reset by default (in accordance to existing Isar
   907 practice);
   908 
   909 * Provers/classical: renamed addaltern to addafter, addSaltern to
   910 addSafter;
   911 
   912 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   913 as well;
   914 
   915 * system: tested support for MacOS X; should be able to get Isabelle +
   916 Proof General to work in a plain Terminal after installing Poly/ML
   917 (e.g. from the Isabelle distribution area) and GNU bash alone
   918 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   919 support requires further installations, e.g. from
   920 http://fink.sourceforge.net/);
   921 
   922 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   923 
   924 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   925 of 40 MB), cf. ML_OPTIONS;
   926 
   927 * system: Proof General keywords specification is now part of the
   928 Isabelle distribution (see etc/isar-keywords.el);
   929 
   930 * system: support for persistent Proof General sessions (refrain from
   931 outdating all loaded theories on startup); user may create writable
   932 logic images like this: ``isabelle -q HOL Test'';
   933 
   934 * system: smart selection of Isabelle process versus Isabelle
   935 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   936 run both "isabelle" and "Isabelle" even if file names are badly
   937 damaged (executable inspects the case of the first letter of its own
   938 name); added separate "isabelle-process" and "isabelle-interface";
   939 
   940 * system: refrain from any attempt at filtering input streams; no
   941 longer support ``8bit'' encoding of old isabelle font, instead proper
   942 iso-latin characters may now be used; the related isatools
   943 "symbolinput" and "nonascii" have disappeared as well;
   944 
   945 * system: removed old "xterm" interface (the print modes "xterm" and
   946 "xterm_color" are still available for direct use in a suitable
   947 terminal);
   948 
   949 
   950 
   951 New in Isabelle99-2 (February 2001)
   952 -----------------------------------
   953 
   954 *** Overview of INCOMPATIBILITIES ***
   955 
   956 * HOL: please note that theories in the Library and elsewhere often use the
   957 new-style (Isar) format; to refer to their theorems in an ML script you must
   958 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   959 
   960 * HOL: inductive package no longer splits induction rule aggressively,
   961 but only as far as specified by the introductions given; the old
   962 format may be recovered via ML function complete_split_rule or attribute
   963 'split_rule (complete)';
   964 
   965 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   966 gfp_Tarski to gfp_unfold;
   967 
   968 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   969 
   970 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   971 relation); infix "^^" has been renamed "``"; infix "``" has been
   972 renamed "`"; "univalent" has been renamed "single_valued";
   973 
   974 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   975 operation;
   976 
   977 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   978 
   979 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   980 
   981 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   982 consequence, it is no longer monotonic wrt. the local goal context
   983 (which is now passed through the inductive cases);
   984 
   985 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   986 \<gg> to \<ggreater>;
   987 
   988 
   989 *** Document preparation ***
   990 
   991 * \isabellestyle{NAME} selects version of Isabelle output (currently
   992 available: are "it" for near math-mode best-style output, "sl" for
   993 slanted text style, and "tt" for plain type-writer; if no
   994 \isabellestyle command is given, output is according to slanted
   995 type-writer);
   996 
   997 * support sub/super scripts (for single symbols only), input syntax is
   998 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   999 
  1000 * some more standard symbols; see Appendix A of the system manual for
  1001 the complete list of symbols defined in isabellesym.sty;
  1002 
  1003 * improved isabelle style files; more abstract symbol implementation
  1004 (should now use \isamath{...} and \isatext{...} in custom symbol
  1005 definitions);
  1006 
  1007 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1008 state; Note that presentation of goal states does not conform to
  1009 actual human-readable proof documents.  Please do not include goal
  1010 states into document output unless you really know what you are doing!
  1011 
  1012 * proper indentation of antiquoted output with proportional LaTeX
  1013 fonts;
  1014 
  1015 * no_document ML operator temporarily disables LaTeX document
  1016 generation;
  1017 
  1018 * isatool unsymbolize tunes sources for plain ASCII communication;
  1019 
  1020 
  1021 *** Isar ***
  1022 
  1023 * Pure: Isar now suffers initial goal statements to contain unbound
  1024 schematic variables (this does not conform to actual readable proof
  1025 documents, due to unpredictable outcome and non-compositional proof
  1026 checking); users who know what they are doing may use schematic goals
  1027 for Prolog-style synthesis of proven results;
  1028 
  1029 * Pure: assumption method (an implicit finishing) now handles actual
  1030 rules as well;
  1031 
  1032 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1033 initial goal, declare "that" only as Pure intro (only for single
  1034 steps); the "that" rule assumption may now be involved in implicit
  1035 finishing, thus ".." becomes a feasible for trivial obtains;
  1036 
  1037 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1038 instance proofs may be performed by "..";
  1039 
  1040 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1041 statements as well;
  1042 
  1043 * Pure: more robust selection of calculational rules;
  1044 
  1045 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1046 rule (as well as the assumption rule);
  1047 
  1048 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1049 lemmas, using the graph browser tool;
  1050 
  1051 * Pure: predict failure of "show" in interactive mode;
  1052 
  1053 * Pure: 'thms_containing' now takes actual terms as arguments;
  1054 
  1055 * HOL: improved method 'induct' --- now handles non-atomic goals
  1056 (potential INCOMPATIBILITY); tuned error handling;
  1057 
  1058 * HOL: cases and induct rules now provide explicit hints about the
  1059 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1060 any remaining facts are inserted into the goal verbatim;
  1061 
  1062 * HOL: local contexts (aka cases) may now contain term bindings as
  1063 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1064 the result to be shown in each case;
  1065 
  1066 * HOL: added 'recdef_tc' command;
  1067 
  1068 * isatool convert assists in eliminating legacy ML scripts;
  1069 
  1070 
  1071 *** HOL ***
  1072 
  1073 * HOL/Library: a collection of generic theories to be used together
  1074 with main HOL; the theory loader path already includes this directory
  1075 by default; the following existing theories have been moved here:
  1076 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1077 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1078 
  1079 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1080 modelling and verification task performed in Isabelle/HOL +
  1081 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1082 
  1083 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1084 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1085 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1086 'domain', this makes the theory consistent with mathematical
  1087 literature;
  1088 
  1089 * HOL basics: added overloaded operations "inverse" and "divide"
  1090 (infix "/"), syntax for generic "abs" operation, generic summation
  1091 operator \<Sum>;
  1092 
  1093 * HOL/typedef: simplified package, provide more useful rules (see also
  1094 HOL/subset.thy);
  1095 
  1096 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1097 now expressed as a proper nested rule (old-style tactic scripts may
  1098 require atomize_strip_tac to cope with non-atomic premises);
  1099 
  1100 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1101 to "split_conv" (old name still available for compatibility);
  1102 
  1103 * HOL: improved concrete syntax for strings (e.g. allows translation
  1104 rules with string literals);
  1105 
  1106 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1107  and Fleuriot's mechanization of analysis, including the transcendental
  1108  functions for the reals;
  1109 
  1110 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1111 
  1112 
  1113 *** CTT ***
  1114 
  1115 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1116 "lam" is displayed as TWO lambda-symbols
  1117 
  1118 * CTT: theory Main now available, containing everything (that is, Bool
  1119 and Arith);
  1120 
  1121 
  1122 *** General ***
  1123 
  1124 * Pure: the Simplifier has been implemented properly as a derived rule
  1125 outside of the actual kernel (at last!); the overall performance
  1126 penalty in practical applications is about 50%, while reliability of
  1127 the Isabelle inference kernel has been greatly improved;
  1128 
  1129 * print modes "brackets" and "no_brackets" control output of nested =>
  1130 (types) and ==> (props); the default behaviour is "brackets";
  1131 
  1132 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1133 as assumptions as well;
  1134 
  1135 * system: support Poly/ML 4.0;
  1136 
  1137 * system: isatool install handles KDE version 1 or 2;
  1138 
  1139 
  1140 
  1141 New in Isabelle99-1 (October 2000)
  1142 ----------------------------------
  1143 
  1144 *** Overview of INCOMPATIBILITIES ***
  1145 
  1146 * HOL: simplification of natural numbers is much changed; to partly
  1147 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1148 issue the following ML commands:
  1149 
  1150   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1151   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1152 
  1153 * HOL: simplification no longer dives into case-expressions; this is
  1154 controlled by "t.weak_case_cong" for each datatype t;
  1155 
  1156 * HOL: nat_less_induct renamed to less_induct;
  1157 
  1158 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1159 fixsome to patch .thy and .ML sources automatically;
  1160 
  1161   select_equality  -> some_equality
  1162   select_eq_Ex     -> some_eq_ex
  1163   selectI2EX       -> someI2_ex
  1164   selectI2         -> someI2
  1165   selectI          -> someI
  1166   select1_equality -> some1_equality
  1167   Eps_sym_eq       -> some_sym_eq_trivial
  1168   Eps_eq           -> some_eq_trivial
  1169 
  1170 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1171 
  1172 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1173 instead);
  1174 
  1175 * HOL: the recursion equations generated by 'recdef' are now called
  1176 f.simps instead of f.rules;
  1177 
  1178 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1179 
  1180 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1181 sometimes be needed;
  1182 
  1183 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1184 
  1185 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1186 
  1187 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1188 product is now "<*>" instead of "Times"; the lexicographic product is
  1189 now "<*lex*>" instead of "**";
  1190 
  1191 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1192 of main HOL, but was unused); better use HOL's datatype package;
  1193 
  1194 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1195 the old syntax may be recovered as follows:
  1196 
  1197   syntax (symbols)
  1198     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1199       (infixl "\\<oplus>" 100)
  1200 
  1201 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1202 
  1203 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1204 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1205 internally;
  1206 
  1207 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1208 changed from A/r to A//r;
  1209 
  1210 * ZF: new treatment of arithmetic (nat & int) may break some old
  1211 proofs;
  1212 
  1213 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1214 rulify -> rule_format, elimify -> elim_format, ...);
  1215 
  1216 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1217 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1218 should have to change intro!! to intro? only); replaced "delrule" by
  1219 "rule del";
  1220 
  1221 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1222 
  1223 * Provers: strengthened force_tac by using new first_best_tac;
  1224 
  1225 * LaTeX document preparation: several changes of isabelle.sty (see
  1226 lib/texinputs);
  1227 
  1228 
  1229 *** Document preparation ***
  1230 
  1231 * formal comments (text blocks etc.) in new-style theories may now
  1232 contain antiquotations of thm/prop/term/typ/text to be presented
  1233 according to latex print mode; concrete syntax is like this:
  1234 @{term[show_types] "f(x) = a + x"};
  1235 
  1236 * isatool mkdir provides easy setup of Isabelle session directories,
  1237 including proper document sources;
  1238 
  1239 * generated LaTeX sources are now deleted after successful run
  1240 (isatool document -c); may retain a copy somewhere else via -D option
  1241 of isatool usedir;
  1242 
  1243 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1244 style files, achieving self-contained LaTeX sources and simplifying
  1245 LaTeX debugging;
  1246 
  1247 * old-style theories now produce (crude) LaTeX output as well;
  1248 
  1249 * browser info session directories are now self-contained (may be put
  1250 on WWW server seperately); improved graphs of nested sessions; removed
  1251 graph for 'all sessions';
  1252 
  1253 * several improvements in isabelle style files; \isabellestyle{it}
  1254 produces fake math mode output; \isamarkupheader is now \section by
  1255 default; see lib/texinputs/isabelle.sty etc.;
  1256 
  1257 
  1258 *** Isar ***
  1259 
  1260 * Isar/Pure: local results and corresponding term bindings are now
  1261 subject to Hindley-Milner polymorphism (similar to ML); this
  1262 accommodates incremental type-inference very nicely;
  1263 
  1264 * Isar/Pure: new derived language element 'obtain' supports
  1265 generalized existence reasoning;
  1266 
  1267 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1268 support accumulation of results, without applying any rules yet;
  1269 useful to collect intermediate results without explicit name
  1270 references, and for use with transitivity rules with more than 2
  1271 premises;
  1272 
  1273 * Isar/Pure: scalable support for case-analysis type proofs: new
  1274 'case' language element refers to local contexts symbolically, as
  1275 produced by certain proof methods; internally, case names are attached
  1276 to theorems as "tags";
  1277 
  1278 * Isar/Pure: theory command 'hide' removes declarations from
  1279 class/type/const name spaces;
  1280 
  1281 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1282 indicate potential overloading;
  1283 
  1284 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1285 
  1286 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1287 "{a,b,c}" instead of {a,b,c};
  1288 
  1289 * Isar/Pure now provides its own version of intro/elim/dest
  1290 attributes; useful for building new logics, but beware of confusion
  1291 with the version in Provers/classical;
  1292 
  1293 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1294 case name 'antecedent';
  1295 
  1296 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1297 to the current context is now done automatically);
  1298 
  1299 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1300 for definining proof methods in ML;
  1301 
  1302 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1303 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1304 most cases, one should have to change intro!! to intro? only);
  1305 replaced "delrule" by "rule del";
  1306 
  1307 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1308 'symmetric' attribute (the latter supercedes [RS sym]);
  1309 
  1310 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1311 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1312 well (including splits);
  1313 
  1314 * Isar/Provers: Simplifier and Classical methods now support all kind
  1315 of modifiers used in the past, including 'cong', 'iff', etc.
  1316 
  1317 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1318 of Simplifier and Classical reasoner);
  1319 
  1320 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1321 now support named cases; major packages (inductive, datatype, primrec,
  1322 recdef) support case names and properly name parameters;
  1323 
  1324 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1325 monotonicity conditions are extracted to be proven at end of
  1326 calculations;
  1327 
  1328 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1329 method anyway;
  1330 
  1331 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1332 split_if split_if_asm; datatype package provides theorems foo.splits =
  1333 foo.split foo.split_asm for each datatype;
  1334 
  1335 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1336 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1337 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1338 use "(cases (simplified))" method in proper proof texts);
  1339 
  1340 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1341 
  1342 * Isar: names of theorems etc. may be natural numbers as well;
  1343 
  1344 * Isar: 'pr' command: optional arguments for goals_limit and
  1345 ProofContext.prems_limit; no longer prints theory contexts, but only
  1346 proof states;
  1347 
  1348 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1349 additional print modes to be specified; e.g. "pr(latex)" will print
  1350 proof state according to the Isabelle LaTeX style;
  1351 
  1352 * Isar: improved support for emulating tactic scripts, including proof
  1353 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1354 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1355 (for HOL datatypes);
  1356 
  1357 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1358 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1359 'proof method scripts' have to be in depth-first order;
  1360 
  1361 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1362 
  1363 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1364 should instead use individual commands for printing items
  1365 (print_commands, print_methods etc.);
  1366 
  1367 * Isar: added 'nothing' --- the empty list of theorems;
  1368 
  1369 
  1370 *** HOL ***
  1371 
  1372 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1373 corresponding virtual machine and a specification of its bytecode
  1374 verifier and a lightweight bytecode verifier, including proofs of
  1375 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1376 Cornelia Pusch (see also the homepage of project Bali at
  1377 http://isabelle.in.tum.de/Bali/);
  1378 
  1379 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1380 Clemens Ballarin;
  1381 
  1382 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1383 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1384 Rasmussen;
  1385 
  1386 * HOL/Lattice: fundamental concepts of lattice theory and order
  1387 structures, including duals, properties of bounds versus algebraic
  1388 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1389 Theorem for complete lattices etc.; may also serve as a demonstration
  1390 for abstract algebraic reasoning using axiomatic type classes, and
  1391 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1392 
  1393 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1394 von Oheimb;
  1395 
  1396 * HOL/IMPP: extension of IMP with local variables and mutually
  1397 recursive procedures, by David von Oheimb;
  1398 
  1399 * HOL/Lambda: converted into new-style theory and document;
  1400 
  1401 * HOL/ex/Multiquote: example of multiple nested quotations and
  1402 anti-quotations -- basically a generalized version of de-Bruijn
  1403 representation; very useful in avoiding lifting of operations;
  1404 
  1405 * HOL/record: added general record equality rule to simpset; fixed
  1406 select-update simplification procedure to handle extended records as
  1407 well; admit "r" as field name;
  1408 
  1409 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1410 other numeric types and also as the identity of groups, rings, etc.;
  1411 
  1412 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1413 Types nat and int belong to this axclass;
  1414 
  1415 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1416    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1417    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1418   two terms #m*u and #n*u are replaced by #(m+n)*u
  1419     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1420   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1421     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1422 
  1423 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1424 powerful prover for predicate logic but knows nothing of clasets; see
  1425 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1426 
  1427 * HOL: new version of "case_tac" subsumes both boolean case split and
  1428 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1429 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1430 
  1431 * HOL: simplification no longer dives into case-expressions: only the
  1432 selector expression is simplified, but not the remaining arms; to
  1433 enable full simplification of case-expressions for datatype t, you may
  1434 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1435 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1436 
  1437 * HOL/recdef: the recursion equations generated by 'recdef' for
  1438 function 'f' are now called f.simps instead of f.rules; if all
  1439 termination conditions are proved automatically, these simplification
  1440 rules are added to the simpset, as in primrec; rules may be named
  1441 individually as well, resulting in a separate list of theorems for
  1442 each equation;
  1443 
  1444 * HOL/While is a new theory that provides a while-combinator. It
  1445 permits the definition of tail-recursive functions without the
  1446 provision of a termination measure. The latter is necessary once the
  1447 invariant proof rule for while is applied.
  1448 
  1449 * HOL: new (overloaded) notation for the set of elements below/above
  1450 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1451 
  1452 * HOL: theorems impI, allI, ballI bound as "strip";
  1453 
  1454 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1455 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1456 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1457 
  1458 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1459 
  1460 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1461 main HOL, but was unused);
  1462 
  1463 * HOL: fewer consts declared as global (e.g. have to refer to
  1464 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1465 
  1466 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1467 in case of overlap with user translations (e.g. judgements over
  1468 tuples); (note that the underlying logical represenation is still
  1469 bogus);
  1470 
  1471 
  1472 *** ZF ***
  1473 
  1474 * ZF: simplification automatically cancels common terms in arithmetic
  1475 expressions over nat and int;
  1476 
  1477 * ZF: new treatment of nat to minimize type-checking: all operators
  1478 coerce their operands to a natural number using the function natify,
  1479 making the algebraic laws unconditional;
  1480 
  1481 * ZF: as above, for int: operators coerce their operands to an integer
  1482 using the function intify;
  1483 
  1484 * ZF: the integer library now contains many of the usual laws for the
  1485 orderings, including $<=, and monotonicity laws for $+ and $*;
  1486 
  1487 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1488 simplification;
  1489 
  1490 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1491 to the simplifier and classical reasoner simultaneously;
  1492 
  1493 
  1494 *** General ***
  1495 
  1496 * Provers: blast_tac now handles actual object-logic rules as
  1497 assumptions; note that auto_tac uses blast_tac internally as well;
  1498 
  1499 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1500 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1501 
  1502 * Provers: delrules now handles destruct rules as well (no longer need
  1503 explicit make_elim);
  1504 
  1505 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1506   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1507 use instead the strong form,
  1508   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1509 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1510 from destruct-rules;
  1511 
  1512 * Provers: Simplifier.easy_setup provides a fast path to basic
  1513 Simplifier setup for new object-logics;
  1514 
  1515 * Pure: AST translation rules no longer require constant head on LHS;
  1516 
  1517 * Pure: improved name spaces: ambiguous output is qualified; support
  1518 for hiding of names;
  1519 
  1520 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1521 XSYMBOL_HOME; no longer need to do manual configuration in most
  1522 situations;
  1523 
  1524 * system: compression of ML heaps images may now be controlled via -c
  1525 option of isabelle and isatool usedir (currently only observed by
  1526 Poly/ML);
  1527 
  1528 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1529 useful for remote X11);
  1530 
  1531 * system: provide TAGS file for Isabelle sources;
  1532 
  1533 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1534 order;
  1535 
  1536 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1537 timing flag supersedes proof_timing and Toplevel.trace;
  1538 
  1539 * ML: new combinators |>> and |>>> for incremental transformations
  1540 with secondary results (e.g. certain theory extensions):
  1541 
  1542 * ML: PureThy.add_defs gets additional argument to indicate potential
  1543 overloading (usually false);
  1544 
  1545 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1546 results;
  1547 
  1548 
  1549 
  1550 New in Isabelle99 (October 1999)
  1551 --------------------------------
  1552 
  1553 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1554 
  1555 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1556 are no longer simplified.  (This allows the simplifier to unfold recursive
  1557 functional programs.)  To restore the old behaviour, declare
  1558 
  1559     Delcongs [if_weak_cong];
  1560 
  1561 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1562 complement;
  1563 
  1564 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1565 
  1566 * HOL/datatype: mutual_induct_tac no longer exists --
  1567   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1568 
  1569 * HOL/typedef: fixed type inference for representing set; type
  1570 arguments now have to occur explicitly on the rhs as type constraints;
  1571 
  1572 * ZF: The con_defs part of an inductive definition may no longer refer
  1573 to constants declared in the same theory;
  1574 
  1575 * HOL, ZF: the function mk_cases, generated by the inductive
  1576 definition package, has lost an argument.  To simplify its result, it
  1577 uses the default simpset instead of a supplied list of theorems.
  1578 
  1579 * HOL/List: the constructors of type list are now Nil and Cons;
  1580 
  1581 * Simplifier: the type of the infix ML functions
  1582         setSSolver addSSolver setSolver addSolver
  1583 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1584 for packaging solvers. A solver is created via
  1585         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1586 where the string argument is only a comment.
  1587 
  1588 
  1589 *** Proof tools ***
  1590 
  1591 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1592 decision procedure for linear arithmetic. Currently it is used for
  1593 types `nat', `int', and `real' in HOL (see below); it can, should and
  1594 will be instantiated for other types and logics as well.
  1595 
  1596 * The simplifier now accepts rewrite rules with flexible heads, eg
  1597      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1598   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1599   matching.
  1600 
  1601 
  1602 *** General ***
  1603 
  1604 * New Isabelle/Isar subsystem provides an alternative to traditional
  1605 tactical theorem proving; together with the ProofGeneral/isar user
  1606 interface it offers an interactive environment for developing human
  1607 readable proof documents (Isar == Intelligible semi-automated
  1608 reasoning); for further information see isatool doc isar-ref,
  1609 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1610 
  1611 * improved and simplified presentation of theories: better HTML markup
  1612 (including colors), graph views in several sizes; isatool usedir now
  1613 provides a proper interface for user theories (via -P option); actual
  1614 document preparation based on (PDF)LaTeX is available as well (for
  1615 new-style theories only); see isatool doc system for more information;
  1616 
  1617 * native support for Proof General, both for classic Isabelle and
  1618 Isabelle/Isar;
  1619 
  1620 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1621 using the graph browser tool;
  1622 
  1623 * Isabelle manuals now also available as PDF;
  1624 
  1625 * theory loader rewritten from scratch (may not be fully
  1626 bug-compatible); old loadpath variable has been replaced by show_path,
  1627 add_path, del_path, reset_path functions; new operations such as
  1628 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1629 isatool doc ref);
  1630 
  1631 * improved isatool install: option -k creates KDE application icon,
  1632 option -p DIR installs standalone binaries;
  1633 
  1634 * added ML_PLATFORM setting (useful for cross-platform installations);
  1635 more robust handling of platform specific ML images for SML/NJ;
  1636 
  1637 * the settings environment is now statically scoped, i.e. it is never
  1638 created again in sub-processes invoked from isabelle, isatool, or
  1639 Isabelle;
  1640 
  1641 * path element specification '~~' refers to '$ISABELLE_HOME';
  1642 
  1643 * in locales, the "assumes" and "defines" parts may be omitted if
  1644 empty;
  1645 
  1646 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1647 long arrows);
  1648 
  1649 * new print_mode "HTML";
  1650 
  1651 * new flag show_tags controls display of tags of theorems (which are
  1652 basically just comments that may be attached by some tools);
  1653 
  1654 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1655 mode and goal output format:
  1656 
  1657 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1658 244c244
  1659 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1660 ---
  1661 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1662 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1663 181c181
  1664 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1665 ---
  1666 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1667 
  1668 * function bind_thms stores lists of theorems (cf. bind_thm);
  1669 
  1670 * new shorthand tactics ftac, eatac, datac, fatac;
  1671 
  1672 * qed (and friends) now accept "" as result name; in that case the
  1673 theorem is not stored, but proper checks and presentation of the
  1674 result still apply;
  1675 
  1676 * theorem database now also indexes constants "Trueprop", "all",
  1677 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1678 
  1679 
  1680 *** HOL ***
  1681 
  1682 ** HOL arithmetic **
  1683 
  1684 * There are now decision procedures for linear arithmetic over nat and
  1685 int:
  1686 
  1687 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1688 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1689 are treated as atomic; subformulae not involving type `nat' or `int'
  1690 are ignored; quantified subformulae are ignored unless they are
  1691 positive universal or negative existential. The tactic has to be
  1692 invoked by hand and can be a little bit slow. In particular, the
  1693 running time is exponential in the number of occurrences of `min' and
  1694 `max', and `-' on `nat'.
  1695 
  1696 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1697 (negated) (in)equalities among the premises and the conclusion into
  1698 account (i.e. no compound formulae) and does not know about `min' and
  1699 `max', and `-' on `nat'. It is fast and is used automatically by the
  1700 simplifier.
  1701 
  1702 NB: At the moment, these decision procedures do not cope with mixed
  1703 nat/int formulae where the two parts interact, such as `m < n ==>
  1704 int(m) < int(n)'.
  1705 
  1706 * HOL/Numeral provides a generic theory of numerals (encoded
  1707 efficiently as bit strings); setup for types nat/int/real is in place;
  1708 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1709 int, existing theories and proof scripts may require a few additional
  1710 type constraints;
  1711 
  1712 * integer division and remainder can now be performed on constant
  1713 arguments;
  1714 
  1715 * many properties of integer multiplication, division and remainder
  1716 are now available;
  1717 
  1718 * An interface to the Stanford Validity Checker (SVC) is available through the
  1719 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1720 are proved automatically.  SVC must be installed separately, and its results
  1721 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1722 invocation of the underlying oracle).  For SVC see
  1723   http://verify.stanford.edu/SVC
  1724 
  1725 * IsaMakefile: the HOL-Real target now builds an actual image;
  1726 
  1727 
  1728 ** HOL misc **
  1729 
  1730 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1731 (in Isabelle/Isar) -- by Gertrud Bauer;
  1732 
  1733 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1734 analysis for assembly languages with subtypes;
  1735 
  1736 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1737 -- avoids syntactic ambiguities and treats state, transition, and
  1738 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1739 changed syntax and (many) tactics;
  1740 
  1741 * HOL/inductive: Now also handles more general introduction rules such
  1742   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1743   theorems are now maintained within the theory (maintained via the
  1744   "mono" attribute);
  1745 
  1746 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1747   (using function types) such as
  1748 
  1749   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1750 
  1751 * HOL/record: record_simproc (part of the default simpset) takes care
  1752 of selectors applied to updated records; record_split_tac is no longer
  1753 part of the default claset; update_defs may now be removed from the
  1754 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1755 
  1756   claset_ref () := claset() addSWrapper record_split_wrapper;
  1757   Delsimprocs [record_simproc]
  1758 
  1759 * HOL/typedef: fixed type inference for representing set; type
  1760 arguments now have to occur explicitly on the rhs as type constraints;
  1761 
  1762 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1763 names rather than an ML expression;
  1764 
  1765 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1766 supplied later.  Program schemes can be defined, such as
  1767     "While B C s = (if B s then While B C (C s) else s)"
  1768 where the well-founded relation can be chosen after B and C have been given.
  1769 
  1770 * HOL/List: the constructors of type list are now Nil and Cons;
  1771 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1772 course, ML tools referring to List.list.op # etc. have to be adapted;
  1773 
  1774 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1775 disabled by default; run isabelle with option -m HOL to get back to
  1776 the original Gordon/HOL-style output;
  1777 
  1778 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1779 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1780 
  1781 * HOL basic syntax simplified (more orthogonal): all variants of
  1782 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1783 Eps operator is provided as well: "SOME x. P[x]";
  1784 
  1785 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1786 
  1787 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1788 thus available for user theories;
  1789 
  1790 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1791 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1792 time;
  1793 
  1794 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1795 several times and then mp;
  1796 
  1797 
  1798 *** LK ***
  1799 
  1800 * the notation <<...>> is now available as a notation for sequences of
  1801 formulas;
  1802 
  1803 * the simplifier is now installed
  1804 
  1805 * the axiom system has been generalized (thanks to Soren Heilmann)
  1806 
  1807 * the classical reasoner now has a default rule database
  1808 
  1809 
  1810 *** ZF ***
  1811 
  1812 * new primrec section allows primitive recursive functions to be given
  1813 directly (as in HOL) over datatypes and the natural numbers;
  1814 
  1815 * new tactics induct_tac and exhaust_tac for induction (or case
  1816 analysis) over datatypes and the natural numbers;
  1817 
  1818 * the datatype declaration of type T now defines the recursor T_rec;
  1819 
  1820 * simplification automatically does freeness reasoning for datatype
  1821 constructors;
  1822 
  1823 * automatic type-inference, with AddTCs command to insert new
  1824 type-checking rules;
  1825 
  1826 * datatype introduction rules are now added as Safe Introduction rules
  1827 to the claset;
  1828 
  1829 * the syntax "if P then x else y" is now available in addition to
  1830 if(P,x,y);
  1831 
  1832 
  1833 *** Internal programming interfaces ***
  1834 
  1835 * tuned simplifier trace output; new flag debug_simp;
  1836 
  1837 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1838 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1839 
  1840 * AxClass.axclass_tac lost the theory argument;
  1841 
  1842 * tuned current_goals_markers semantics: begin / end goal avoids
  1843 printing empty lines;
  1844 
  1845 * removed prs and prs_fn hook, which was broken because it did not
  1846 include \n in its semantics, forcing writeln to add one
  1847 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1848 string -> unit if you really want to output text without newline;
  1849 
  1850 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1851 plain output, interface builders may have to enable 'isabelle_font'
  1852 mode to get Isabelle font glyphs as before;
  1853 
  1854 * refined token_translation interface; INCOMPATIBILITY: output length
  1855 now of type real instead of int;
  1856 
  1857 * theory loader actions may be traced via new ThyInfo.add_hook
  1858 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1859 your own database of information attached to *whole* theories -- as
  1860 opposed to intra-theory data slots offered via TheoryDataFun;
  1861 
  1862 * proper handling of dangling sort hypotheses (at last!);
  1863 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1864 extra sort hypotheses that can be witnessed from the type signature;
  1865 the force_strip_shyps flag is gone, any remaining shyps are simply
  1866 left in the theorem (with a warning issued by strip_shyps_warning);
  1867 
  1868 
  1869 
  1870 New in Isabelle98-1 (October 1998)
  1871 ----------------------------------
  1872 
  1873 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1874 
  1875 * several changes of automated proof tools;
  1876 
  1877 * HOL: major changes to the inductive and datatype packages, including
  1878 some minor incompatibilities of theory syntax;
  1879 
  1880 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1881 called `inj_on';
  1882 
  1883 * HOL: removed duplicate thms in Arith:
  1884   less_imp_add_less  should be replaced by  trans_less_add1
  1885   le_imp_add_le      should be replaced by  trans_le_add1
  1886 
  1887 * HOL: unary minus is now overloaded (new type constraints may be
  1888 required);
  1889 
  1890 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1891 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1892 now taken as an integer constant.
  1893 
  1894 * Pure: ML function 'theory_of' renamed to 'theory';
  1895 
  1896 
  1897 *** Proof tools ***
  1898 
  1899 * Simplifier:
  1900   1. Asm_full_simp_tac is now more aggressive.
  1901      1. It will sometimes reorient premises if that increases their power to
  1902         simplify.
  1903      2. It does no longer proceed strictly from left to right but may also
  1904         rotate premises to achieve further simplification.
  1905      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1906      old Asm_full_simp_tac in that it does not rotate premises.
  1907   2. The simplifier now knows a little bit about nat-arithmetic.
  1908 
  1909 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1910 allows for selected deletion of wrappers, by introduction of names for
  1911 wrapper functionals.  This implies that addbefore, addSbefore,
  1912 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1913 and that adding two tactics with the same name overwrites the first
  1914 one (emitting a warning).
  1915   type wrapper = (int -> tactic) -> (int -> tactic)
  1916   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1917   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1918   delWrapper, delSWrapper: claset *  string            -> claset
  1919   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1920 
  1921 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1922 semantics; addbefore now affects only the unsafe part of step_tac
  1923 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1924 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1925 by Force_tac;
  1926 
  1927 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1928 compWrapper; added safe wrapper (and access functions for it);
  1929 
  1930 * HOL/split_all_tac is now much faster and fails if there is nothing
  1931 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1932 and the names of the automatically generated variables have changed.
  1933 split_all_tac has moved within claset() from unsafe wrappers to safe
  1934 wrappers, which means that !!-bound variables are split much more
  1935 aggressively, and safe_tac and clarify_tac now split such variables.
  1936 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1937 Note: the same holds for record_split_tac, which does the job of
  1938 split_all_tac for record fields.
  1939 
  1940 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1941 permanently to the default simpset using Addsplits just like
  1942 Addsimps. They can be removed via Delsplits just like
  1943 Delsimps. Lower-case versions are also available.
  1944 
  1945 * HOL/Simplifier: The rule split_if is now part of the default
  1946 simpset. This means that the simplifier will eliminate all occurrences
  1947 of if-then-else in the conclusion of a goal. To prevent this, you can
  1948 either remove split_if completely from the default simpset by
  1949 `Delsplits [split_if]' or remove it in a specific call of the
  1950 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1951 other case splitting rules to/from the default simpset: every datatype
  1952 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1953 t is the name of the datatype).
  1954 
  1955 * Classical reasoner / Simplifier combination: new force_tac (and
  1956 derivatives Force_tac, force) combines rewriting and classical
  1957 reasoning (and whatever other tools) similarly to auto_tac, but is
  1958 aimed to solve the given subgoal completely.
  1959 
  1960 
  1961 *** General ***
  1962 
  1963 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1964 and `goalw': the theory is no longer needed as an explicit argument -
  1965 the current theory context is used; assumptions are no longer returned
  1966 at the ML-level unless one of them starts with ==> or !!; it is
  1967 recommended to convert to these new commands using isatool fixgoal
  1968 (backup your sources first!);
  1969 
  1970 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1971 the current theory context, and 'theory' to lookup stored theories;
  1972 
  1973 * new theory section 'locale' for declaring constants, assumptions and
  1974 definitions that have local scope;
  1975 
  1976 * new theory section 'nonterminals' for purely syntactic types;
  1977 
  1978 * new theory section 'setup' for generic ML setup functions
  1979 (e.g. package initialization);
  1980 
  1981 * the distribution now includes Isabelle icons: see
  1982 lib/logo/isabelle-{small,tiny}.xpm;
  1983 
  1984 * isatool install - install binaries with absolute references to
  1985 ISABELLE_HOME/bin;
  1986 
  1987 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1988 
  1989 * print mode 'emacs' reserved for Isamode;
  1990 
  1991 * support multiple print (ast) translations per constant name;
  1992 
  1993 * theorems involving oracles are now printed with a suffixed [!];
  1994 
  1995 
  1996 *** HOL ***
  1997 
  1998 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1999 
  2000 * HOL/inductive package reorganized and improved: now supports mutual
  2001 definitions such as
  2002 
  2003   inductive EVEN ODD
  2004     intrs
  2005       null "0 : EVEN"
  2006       oddI "n : EVEN ==> Suc n : ODD"
  2007       evenI "n : ODD ==> Suc n : EVEN"
  2008 
  2009 new theorem list "elims" contains an elimination rule for each of the
  2010 recursive sets; inductive definitions now handle disjunctive premises
  2011 correctly (also ZF);
  2012 
  2013 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2014 "mutual_induct" no longer exists - the induction rule is always
  2015 contained in "induct";
  2016 
  2017 
  2018 * HOL/datatype package re-implemented and greatly improved: now
  2019 supports mutually recursive datatypes such as
  2020 
  2021   datatype
  2022     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2023             | SUM ('a aexp) ('a aexp)
  2024             | DIFF ('a aexp) ('a aexp)
  2025             | NUM 'a
  2026   and
  2027     'a bexp = LESS ('a aexp) ('a aexp)
  2028             | AND ('a bexp) ('a bexp)
  2029             | OR ('a bexp) ('a bexp)
  2030 
  2031 as well as indirectly recursive datatypes such as
  2032 
  2033   datatype
  2034     ('a, 'b) term = Var 'a
  2035                   | App 'b ((('a, 'b) term) list)
  2036 
  2037 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2038 induction on mutually / indirectly recursive datatypes.
  2039 
  2040 Primrec equations are now stored in theory and can be accessed via
  2041 <function_name>.simps.
  2042 
  2043 INCOMPATIBILITIES:
  2044 
  2045   - Theories using datatypes must now have theory Datatype as an
  2046     ancestor.
  2047   - The specific <typename>.induct_tac no longer exists - use the
  2048     generic induct_tac instead.
  2049   - natE has been renamed to nat.exhaust - use exhaust_tac
  2050     instead of res_inst_tac ... natE. Note that the variable
  2051     names in nat.exhaust differ from the names in natE, this
  2052     may cause some "fragile" proofs to fail.
  2053   - The theorems split_<typename>_case and split_<typename>_case_asm
  2054     have been renamed to <typename>.split and <typename>.split_asm.
  2055   - Since default sorts of type variables are now handled correctly,
  2056     some datatype definitions may have to be annotated with explicit
  2057     sort constraints.
  2058   - Primrec definitions no longer require function name and type
  2059     of recursive argument.
  2060 
  2061 Consider using isatool fixdatatype to adapt your theories and proof
  2062 scripts to the new package (backup your sources first!).
  2063 
  2064 
  2065 * HOL/record package: considerably improved implementation; now
  2066 includes concrete syntax for record types, terms, updates; theorems
  2067 for surjective pairing and splitting !!-bound record variables; proof
  2068 support is as follows:
  2069 
  2070   1) standard conversions (selectors or updates applied to record
  2071 constructor terms) are part of the standard simpset;
  2072 
  2073   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2074 made part of standard simpset and claset via addIffs;
  2075 
  2076   3) a tactic for record field splitting (record_split_tac) is part of
  2077 the standard claset (addSWrapper);
  2078 
  2079 To get a better idea about these rules you may retrieve them via
  2080 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2081 the name of your record type.
  2082 
  2083 The split tactic 3) conceptually simplifies by the following rule:
  2084 
  2085   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2086 
  2087 Thus any record variable that is bound by meta-all will automatically
  2088 blow up into some record constructor term, consequently the
  2089 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2090 solve record problems automatically.
  2091 
  2092 
  2093 * reorganized the main HOL image: HOL/Integ and String loaded by
  2094 default; theory Main includes everything;
  2095 
  2096 * automatic simplification of integer sums and comparisons, using cancellation;
  2097 
  2098 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2099 
  2100 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2101 
  2102 * many new identities for unions, intersections, set difference, etc.;
  2103 
  2104 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2105 called split_if, split_split, split_sum_case and split_nat_case (to go
  2106 with add/delsplits);
  2107 
  2108 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2109 (?x::unit) = (); this is made part of the default simpset, which COULD
  2110 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2111 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2112 unit_abs_eta_conv is added in order to counter the effect of
  2113 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2114 %u.f();
  2115 
  2116 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2117 makes more sense);
  2118 
  2119 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2120   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2121   disjointness reasoning but breaking a few old proofs.
  2122 
  2123 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2124 to 'converse' from 'inverse' (for compatibility with ZF and some
  2125 literature);
  2126 
  2127 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2128 the well-founded relation;
  2129 
  2130 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2131     Compl A.  The "Compl" syntax remains available as input syntax for this
  2132     release ONLY.
  2133 
  2134 * HOL/Update: new theory of function updates:
  2135     f(a:=b) == %x. if x=a then b else f x
  2136 may also be iterated as in f(a:=b,c:=d,...);
  2137 
  2138 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2139 
  2140 * HOL/List:
  2141   - new function list_update written xs[i:=v] that updates the i-th
  2142     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2143   - new function `upt' written [i..j(] which generates the list
  2144     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2145     bound write [i..j], which is a shorthand for [i..j+1(].
  2146   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2147 
  2148 * HOL/Arith:
  2149   - removed 'pred' (predecessor) function;
  2150   - generalized some theorems about n-1;
  2151   - many new laws about "div" and "mod";
  2152   - new laws about greatest common divisors (see theory ex/Primes);
  2153 
  2154 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2155 instead of "inverse";
  2156 
  2157 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2158   of the multiset ordering;
  2159 
  2160 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2161   (not included by default);
  2162 
  2163 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2164 
  2165 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2166   programs, i.e. different program variables may have different types.
  2167 
  2168 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2169   [previously, this check worked only if the rewrite rule was unconditional]
  2170   Now rew can involve either definitions or equalities (either == or =).
  2171 
  2172 
  2173 *** ZF ***
  2174 
  2175 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2176   only the theorems proved on ZF.ML;
  2177 
  2178 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2179   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2180   disjointness reasoning but breaking a few old proofs.
  2181 
  2182 * ZF/Update: new theory of function updates
  2183     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2184   may also be iterated as in f(a:=b,c:=d,...);
  2185 
  2186 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2187 
  2188 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2189   [previously, this check worked only if the rewrite rule was unconditional]
  2190   Now rew can involve either definitions or equalities (either == or =).
  2191 
  2192 * case_tac provided for compatibility with HOL
  2193     (like the old excluded_middle_tac, but with subgoals swapped)
  2194 
  2195 
  2196 *** Internal programming interfaces ***
  2197 
  2198 * Pure: several new basic modules made available for general use, see
  2199 also src/Pure/README;
  2200 
  2201 * improved the theory data mechanism to support encapsulation (data
  2202 kind name replaced by private Object.kind, acting as authorization
  2203 key); new type-safe user interface via functor TheoryDataFun; generic
  2204 print_data function becomes basically useless;
  2205 
  2206 * removed global_names compatibility flag -- all theory declarations
  2207 are qualified by default;
  2208 
  2209 * module Pure/Syntax now offers quote / antiquote translation
  2210 functions (useful for Hoare logic etc. with implicit dependencies);
  2211 see HOL/ex/Antiquote for an example use;
  2212 
  2213 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2214 cterm -> thm;
  2215 
  2216 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2217 subgoal;
  2218 
  2219 * Display.print_goals function moved to Locale.print_goals;
  2220 
  2221 * standard print function for goals supports current_goals_markers
  2222 variable for marking begin of proof, end of proof, start of goal; the
  2223 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2224 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2225 for example;
  2226 
  2227 
  2228 
  2229 New in Isabelle98 (January 1998)
  2230 --------------------------------
  2231 
  2232 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2233 
  2234 * changed lexical syntax of terms / types: dots made part of long
  2235 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2236 
  2237 * simpset (and claset) reference variable replaced by functions
  2238 simpset / simpset_ref;
  2239 
  2240 * no longer supports theory aliases (via merge) and non-trivial
  2241 implicit merge of thms' signatures;
  2242 
  2243 * most internal names of constants changed due to qualified names;
  2244 
  2245 * changed Pure/Sequence interface (see Pure/seq.ML);
  2246 
  2247 
  2248 *** General Changes ***
  2249 
  2250 * hierachically structured name spaces (for consts, types, axms, thms
  2251 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2252 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2253 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2254 long_names for fully qualified output names; NOTE: ML programs
  2255 (special tactics, packages etc.) referring to internal names may have
  2256 to be adapted to cope with fully qualified names; in case of severe
  2257 backward campatibility problems try setting 'global_names' at compile
  2258 time to have enrything declared within a flat name space; one may also
  2259 fine tune name declarations in theories via the 'global' and 'local'
  2260 section;
  2261 
  2262 * reimplemented the implicit simpset and claset using the new anytype
  2263 data filed in signatures; references simpset:simpset ref etc. are
  2264 replaced by functions simpset:unit->simpset and
  2265 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2266 to patch your ML files accordingly;
  2267 
  2268 * HTML output now includes theory graph data for display with Java
  2269 applet or isatool browser; data generated automatically via isatool
  2270 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2271 
  2272 * defs may now be conditional; improved rewrite_goals_tac to handle
  2273 conditional equations;
  2274 
  2275 * defs now admits additional type arguments, using TYPE('a) syntax;
  2276 
  2277 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2278 creates a new theory node; implicit merge of thms' signatures is
  2279 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2280 transfer:theory->thm->thm in (rare) cases;
  2281 
  2282 * improved handling of draft signatures / theories; draft thms (and
  2283 ctyps, cterms) are automatically promoted to real ones;
  2284 
  2285 * slightly changed interfaces for oracles: admit many per theory, named
  2286 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2287 
  2288 * print_goals: optional output of const types (set show_consts and
  2289 show_types);
  2290 
  2291 * improved output of warnings (###) and errors (***);
  2292 
  2293 * subgoal_tac displays a warning if the new subgoal has type variables;
  2294 
  2295 * removed old README and Makefiles;
  2296 
  2297 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2298 
  2299 * removed obsolete init_pps and init_database;
  2300 
  2301 * deleted the obsolete tactical STATE, which was declared by
  2302     fun STATE tacfun st = tacfun st st;
  2303 
  2304 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2305 (which abbreviates $HOME);
  2306 
  2307 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2308 use isatool fixseq to adapt your ML programs (this works for fully
  2309 qualified references to the Sequence structure only!);
  2310 
  2311 * use_thy no longer requires writable current directory; it always
  2312 reloads .ML *and* .thy file, if either one is out of date;
  2313 
  2314 
  2315 *** Classical Reasoner ***
  2316 
  2317 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2318 tactics that use classical reasoning to simplify a subgoal without
  2319 splitting it into several subgoals;
  2320 
  2321 * Safe_tac: like safe_tac but uses the default claset;
  2322 
  2323 
  2324 *** Simplifier ***
  2325 
  2326 * added simplification meta rules:
  2327     (asm_)(full_)simplify: simpset -> thm -> thm;
  2328 
  2329 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2330 logics (again);
  2331 
  2332 * added prems argument to simplification procedures;
  2333 
  2334 * HOL, FOL, ZF: added infix function `addsplits':
  2335   instead of `<simpset> setloop (split_tac <thms>)'
  2336   you can simply write `<simpset> addsplits <thms>'
  2337 
  2338 
  2339 *** Syntax ***
  2340 
  2341 * TYPE('a) syntax for type reflection terms;
  2342 
  2343 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2344 
  2345 * pretty printer: changed order of mixfix annotation preference (again!);
  2346 
  2347 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2348 
  2349 
  2350 *** HOL ***
  2351 
  2352 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2353   with `addloop' of the simplifier to faciliate case splitting in premises.
  2354 
  2355 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2356 
  2357 * HOL/Auth: new protocol proofs including some for the Internet
  2358   protocol TLS;
  2359 
  2360 * HOL/Map: new theory of `maps' a la VDM;
  2361 
  2362 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2363 cancelling out common nat summands from =, <, <= (in)equalities, or
  2364 differences; simplification procedures nat_cancel_factor for
  2365 cancelling common factor from =, <, <= (in)equalities over natural
  2366 sums; nat_cancel contains both kinds of procedures, it is installed by
  2367 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2368 
  2369 * HOL/simplifier: terms of the form
  2370   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2371   are rewritten to
  2372   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2373   and those of the form
  2374   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2375   are rewritten to
  2376   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2377 
  2378 * HOL/datatype
  2379   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2380 
  2381   P(t_case f1 ... fn x) =
  2382      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2383         ...
  2384        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2385      )
  2386 
  2387   and a theorem `split_t_case_asm' of the form
  2388 
  2389   P(t_case f1 ... fn x) =
  2390     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2391         ...
  2392        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2393      )
  2394   which can be added to a simpset via `addsplits'. The existing theorems
  2395   expand_list_case and expand_option_case have been renamed to
  2396   split_list_case and split_option_case.
  2397 
  2398 * HOL/Arithmetic:
  2399   - `pred n' is automatically converted to `n-1'.
  2400     Users are strongly encouraged not to use `pred' any longer,
  2401     because it will disappear altogether at some point.
  2402   - Users are strongly encouraged to write "0 < n" rather than
  2403     "n ~= 0". Theorems and proof tools have been modified towards this
  2404     `standard'.
  2405 
  2406 * HOL/Lists:
  2407   the function "set_of_list" has been renamed "set" (and its theorems too);
  2408   the function "nth" now takes its arguments in the reverse order and
  2409   has acquired the infix notation "!" as in "xs!n".
  2410 
  2411 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2412 
  2413 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2414   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2415 
  2416 * HOL/record: extensible records with schematic structural subtyping
  2417 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2418 still lacks various theorems and concrete record syntax;
  2419 
  2420 
  2421 *** HOLCF ***
  2422 
  2423 * removed "axioms" and "generated by" sections;
  2424 
  2425 * replaced "ops" section by extended "consts" section, which is capable of
  2426   handling the continuous function space "->" directly;
  2427 
  2428 * domain package:
  2429   . proves theorems immediately and stores them in the theory,
  2430   . creates hierachical name space,
  2431   . now uses normal mixfix annotations (instead of cinfix...),
  2432   . minor changes to some names and values (for consistency),
  2433   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2434   . separator between mutual domain defs: changed "," to "and",
  2435   . improved handling of sort constraints;  now they have to
  2436     appear on the left-hand side of the equations only;
  2437 
  2438 * fixed LAM <x,y,zs>.b syntax;
  2439 
  2440 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2441 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2442 
  2443 
  2444 *** FOL and ZF ***
  2445 
  2446 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2447   with `addloop' of the simplifier to faciliate case splitting in premises.
  2448 
  2449 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2450 in HOL, they strip ALL and --> from proved theorems;
  2451 
  2452 
  2453 
  2454 New in Isabelle94-8 (May 1997)
  2455 ------------------------------
  2456 
  2457 *** General Changes ***
  2458 
  2459 * new utilities to build / run / maintain Isabelle etc. (in parts
  2460 still somewhat experimental); old Makefiles etc. still functional;
  2461 
  2462 * new 'Isabelle System Manual';
  2463 
  2464 * INSTALL text, together with ./configure and ./build scripts;
  2465 
  2466 * reimplemented type inference for greater efficiency, better error
  2467 messages and clean internal interface;
  2468 
  2469 * prlim command for dealing with lots of subgoals (an easier way of
  2470 setting goals_limit);
  2471 
  2472 
  2473 *** Syntax ***
  2474 
  2475 * supports alternative (named) syntax tables (parser and pretty
  2476 printer); internal interface is provided by add_modesyntax(_i);
  2477 
  2478 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2479 be used in conjunction with the Isabelle symbol font; uses the
  2480 "symbols" syntax table;
  2481 
  2482 * added token_translation interface (may translate name tokens in
  2483 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2484 the current print_mode); IMPORTANT: user print translation functions
  2485 are responsible for marking newly introduced bounds
  2486 (Syntax.mark_boundT);
  2487 
  2488 * token translations for modes "xterm" and "xterm_color" that display
  2489 names in bold, underline etc. or colors (which requires a color
  2490 version of xterm);
  2491 
  2492 * infixes may now be declared with names independent of their syntax;
  2493 
  2494 * added typed_print_translation (like print_translation, but may
  2495 access type of constant);
  2496 
  2497 
  2498 *** Classical Reasoner ***
  2499 
  2500 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2501 some limitations.  Blast_tac...
  2502   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2503   + ignores elimination rules that don't have the correct format
  2504         (the conclusion MUST be a formula variable)
  2505   + ignores types, which can make HOL proofs fail
  2506   + rules must not require higher-order unification, e.g. apply_type in ZF
  2507     [message "Function Var's argument not a bound variable" relates to this]
  2508   + its proof strategy is more general but can actually be slower
  2509 
  2510 * substitution with equality assumptions no longer permutes other
  2511 assumptions;
  2512 
  2513 * minor changes in semantics of addafter (now called addaltern); renamed
  2514 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2515 (and access functions for it);
  2516 
  2517 * improved combination of classical reasoner and simplifier:
  2518   + functions for handling clasimpsets
  2519   + improvement of addss: now the simplifier is called _after_ the
  2520     safe steps.
  2521   + safe variant of addss called addSss: uses safe simplifications
  2522     _during_ the safe steps. It is more complete as it allows multiple
  2523     instantiations of unknowns (e.g. with slow_tac).
  2524 
  2525 *** Simplifier ***
  2526 
  2527 * added interface for simplification procedures (functions that
  2528 produce *proven* rewrite rules on the fly, depending on current
  2529 redex);
  2530 
  2531 * ordering on terms as parameter (used for ordered rewriting);
  2532 
  2533 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2534 
  2535 * the solver is now split into a safe and an unsafe part.
  2536 This should be invisible for the normal user, except that the
  2537 functions setsolver and addsolver have been renamed to setSolver and
  2538 addSolver; added safe_asm_full_simp_tac;
  2539 
  2540 
  2541 *** HOL ***
  2542 
  2543 * a generic induction tactic `induct_tac' which works for all datatypes and
  2544 also for type `nat';
  2545 
  2546 * a generic case distinction tactic `exhaust_tac' which works for all
  2547 datatypes and also for type `nat';
  2548 
  2549 * each datatype comes with a function `size';
  2550 
  2551 * patterns in case expressions allow tuple patterns as arguments to
  2552 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2553 
  2554 * primrec now also works with type nat;
  2555 
  2556 * recdef: a new declaration form, allows general recursive functions to be
  2557 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2558 
  2559 * the constant for negation has been renamed from "not" to "Not" to
  2560 harmonize with FOL, ZF, LK, etc.;
  2561 
  2562 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2563 infinite lists;
  2564 
  2565 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2566 
  2567 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2568 problems in commutative rings, using axiomatic type classes for + and *;
  2569 
  2570 * more examples in HOL/MiniML and HOL/Auth;
  2571 
  2572 * more default rewrite rules for quantifiers, union/intersection;
  2573 
  2574 * a new constant `arbitrary == @x.False';
  2575 
  2576 * HOLCF/IOA replaces old HOL/IOA;
  2577 
  2578 * HOLCF changes: derived all rules and arities
  2579   + axiomatic type classes instead of classes
  2580   + typedef instead of faking type definitions
  2581   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2582   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2583   + eliminated the types void, one, tr
  2584   + use unit lift and bool lift (with translations) instead of one and tr
  2585   + eliminated blift from Lift3.thy (use Def instead of blift)
  2586   all eliminated rules are derived as theorems --> no visible changes ;
  2587 
  2588 
  2589 *** ZF ***
  2590 
  2591 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2592 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2593 as ZF_cs addSIs [equalityI];
  2594 
  2595 
  2596 
  2597 New in Isabelle94-7 (November 96)
  2598 ---------------------------------
  2599 
  2600 * allowing negative levels (as offsets) in prlev and choplev;
  2601 
  2602 * super-linear speedup for large simplifications;
  2603 
  2604 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2605 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2606 FAIL); can suppress it using the command Delsimps (ex_simps @
  2607 all_simps); De Morgan laws are also now included, by default;
  2608 
  2609 * improved printing of ==>  :  ~:
  2610 
  2611 * new object-logic "Sequents" adds linear logic, while replacing LK
  2612 and Modal (thanks to Sara Kalvala);
  2613 
  2614 * HOL/Auth: correctness proofs for authentication protocols;
  2615 
  2616 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2617 examples on HOL/Auth);
  2618 
  2619 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2620 the rewriter and classical reasoner simultaneously;
  2621 
  2622 * function uresult no longer returns theorems in "standard" format;
  2623 regain previous version by: val uresult = standard o uresult;
  2624 
  2625 
  2626 
  2627 New in Isabelle94-6
  2628 -------------------
  2629 
  2630 * oracles -- these establish an interface between Isabelle and trusted
  2631 external reasoners, which may deliver results as theorems;
  2632 
  2633 * proof objects (in particular record all uses of oracles);
  2634 
  2635 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2636 
  2637 * "constdefs" section in theory files;
  2638 
  2639 * "primrec" section (HOL) no longer requires names;
  2640 
  2641 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2642 
  2643 
  2644 
  2645 New in Isabelle94-5
  2646 -------------------
  2647 
  2648 * reduced space requirements;
  2649 
  2650 * automatic HTML generation from theories;
  2651 
  2652 * theory files no longer require "..." (quotes) around most types;
  2653 
  2654 * new examples, including two proofs of the Church-Rosser theorem;
  2655 
  2656 * non-curried (1994) version of HOL is no longer distributed;
  2657 
  2658 
  2659 
  2660 New in Isabelle94-4
  2661 -------------------
  2662 
  2663 * greatly reduced space requirements;
  2664 
  2665 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2666 
  2667 * searchable theorem database (see the section "Retrieving theorems" on
  2668 page 8 of the Reference Manual);
  2669 
  2670 * new examples, including Grabczewski's monumental case study of the
  2671 Axiom of Choice;
  2672 
  2673 * The previous version of HOL renamed to Old_HOL;
  2674 
  2675 * The new version of HOL (previously called CHOL) uses a curried syntax
  2676 for functions.  Application looks like f a b instead of f(a,b);
  2677 
  2678 * Mutually recursive inductive definitions finally work in HOL;
  2679 
  2680 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2681 translates to the operator "split";
  2682 
  2683 
  2684 
  2685 New in Isabelle94-3
  2686 -------------------
  2687 
  2688 * new infix operator, addss, allowing the classical reasoner to
  2689 perform simplification at each step of its search.  Example:
  2690         fast_tac (cs addss ss)
  2691 
  2692 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2693 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2694 look like (a,b) instead of <a,b>;
  2695 
  2696 * PLEASE NOTE: CHOL will eventually replace HOL!
  2697 
  2698 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2699 It translates to the operator "split".  A new theory of integers is available;
  2700 
  2701 * In ZF, integer numerals now denote two's-complement binary integers.
  2702 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2703 
  2704 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2705 of the Axiom of Choice;
  2706 
  2707 
  2708 
  2709 New in Isabelle94-2
  2710 -------------------
  2711 
  2712 * Significantly faster resolution;
  2713 
  2714 * the different sections in a .thy file can now be mixed and repeated
  2715 freely;
  2716 
  2717 * Database of theorems for FOL, HOL and ZF.  New
  2718 commands including qed, qed_goal and bind_thm store theorems in the database.
  2719 
  2720 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2721 a given theory (thms_of), or find out what theory a theorem was proved in
  2722 (theory_of_thm);
  2723 
  2724 * Bugs fixed in the inductive definition and datatype packages;
  2725 
  2726 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2727 and HOL_dup_cs obsolete;
  2728 
  2729 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2730 have been removed;
  2731 
  2732 * Simpler definition of function space in ZF;
  2733 
  2734 * new results about cardinal and ordinal arithmetic in ZF;
  2735 
  2736 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2737 types;
  2738 
  2739 
  2740 $Id$