NEWS
author wenzelm
Thu May 06 14:17:07 2004 +0200 (2004-05-06)
changeset 14707 2d6350d7b9b7
parent 14700 2f885b7e5ba7
child 14709 d01983034ded
permissions -rw-r--r--
show_structs option;
     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 an
    15 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: 'advanced' translation functions (parse_translation etc.) may
    28 depend on the signature of the theory context being presently used for
    29 parsing/printing, see also isar-ref manual.
    30 
    31 * Pure: tuned internal renaming of symbolic identifiers -- attach
    32 primes instead of base 26 numbers.
    33 
    34 
    35 *** HOL ***
    36 
    37 * HOL/record: reimplementation of records to avoid performance
    38 problems for type inference. Records are no longer composed of nested
    39 field types, but of nested extension types. Therefore the record type
    40 only grows linear in the number of extensions and not in the number of
    41 fields.  The top-level (users) view on records is preserved.
    42 Potential INCOMPATIBILITY only in strange cases, where the theory
    43 depends on the old record representation. The type generated for a
    44 record is called <record_name>_ext_type.
    45 
    46 
    47 *** HOLCF ***
    48 
    49 * HOLCF: discontinued special version of 'constdefs' (which used to
    50 support continuous functions) in favor of the general Pure one with
    51 full type-inference.
    52 
    53 
    54 
    55 New in Isabelle2004 (April 2004)
    56 --------------------------------
    57 
    58 *** General ***
    59 
    60 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
    61   Replaces linorder.ML.
    62 
    63 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
    64   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
    65   (\<a>...\<z>), are now considered normal letters, and can therefore
    66   be used anywhere where an ASCII letter (a...zA...Z) has until
    67   now. COMPATIBILITY: This obviously changes the parsing of some
    68   terms, especially where a symbol has been used as a binder, say
    69   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
    70   as an identifier.  Fix it by inserting a space around former
    71   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
    72   existing theory and ML files.
    73 
    74 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
    75 
    76 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now 
    77   allowed in identifiers. Similar to Greek letters \<^isub> is now considered 
    78   a normal (but invisible) letter. For multiple letter subscripts repeat 
    79   \<^isub> like this: x\<^isub>1\<^isub>2. 
    80 
    81 * Pure: There are now sub-/superscripts that can span more than one
    82   character. Text between \<^bsub> and \<^esub> is set in subscript in
    83   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
    84   superscript. The new control characters are not identifier parts.
    85 
    86 * Pure: Control-symbols of the form \<^raw:...> will literally print the
    87   content of "..." to the latex file instead of \isacntrl... . The "..."
    88   may consist of any printable characters excluding the end bracket >.
    89 
    90 * Pure: Using new Isar command "finalconsts" (or the ML functions
    91   Theory.add_finals or Theory.add_finals_i) it is now possible to
    92   declare constants "final", which prevents their being given a definition
    93   later.  It is useful for constants whose behaviour is fixed axiomatically
    94   rather than definitionally, such as the meta-logic connectives.
    95 
    96 * Pure: 'instance' now handles general arities with general sorts
    97   (i.e. intersections of classes),
    98 
    99 * Presentation: generated HTML now uses a CSS style sheet to make layout
   100   (somewhat) independent of content. It is copied from lib/html/isabelle.css. 
   101   It can be changed to alter the colors/layout of generated pages.
   102 
   103 
   104 *** Isar ***
   105 
   106 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   107   cut_tac, subgoal_tac and thin_tac:
   108   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   109     locales are no longer forced to write Isar proof scripts.
   110     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   111     emulations.
   112   - INCOMPATIBILITY: names of variables to be instantiated may no
   113     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   114     This is consistent with the instantiation attribute "where".
   115 
   116 * Attributes "where" and "of":
   117   - Now take type variables of instantiated theorem into account when reading
   118     the instantiation string.  This fixes a bug that caused instantiated
   119     theorems to have too special types in some circumstances.
   120   - "where" permits explicit instantiations of type variables.
   121 
   122 * Calculation commands "moreover" and "also" no longer interfere with
   123   current facts ("this"), admitting arbitrary combinations with "then"
   124   and derived forms.
   125 
   126 * Locales:
   127   - Goal statements involving the context element "includes" no longer
   128     generate theorems with internal delta predicates (those ending on
   129     "_axioms") in the premise.
   130     Resolve particular premise with <locale>.intro to obtain old form.
   131   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   132     specification and "includes" elements in goal statement.
   133   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   134     [intro?] and [elim?] (respectively) by default.
   135   - Experimental command for instantiation of locales in proof contexts:
   136         instantiate <label>[<attrs>]: <loc>
   137     Instantiates locale <loc> and adds all its theorems to the current context
   138     taking into account their attributes.  Label and attrs are optional
   139     modifiers, like in theorem declarations.  If present, names of
   140     instantiated theorems are qualified with <label>, and the attributes
   141     <attrs> are applied after any attributes these theorems might have already.
   142       If the locale has assumptions, a chained fact of the form
   143     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   144     are derived.  The command does not support old-style locales declared
   145     with "locale (open)".
   146       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   147 
   148 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   149   (Isar) contexts.
   150 
   151 
   152 *** HOL ***
   153 
   154 * Proof import: new image HOL4 contains the imported library from
   155   the HOL4 system with about 2500 theorems. It is imported by
   156   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   157   can be used like any other Isabelle image.  See
   158   HOL/Import/HOL/README for more information.
   159 
   160 * Simplifier:
   161   - Much improved handling of linear and partial orders.
   162     Reasoners for linear and partial orders are set up for type classes
   163     "linorder" and "order" respectively, and are added to the default simpset
   164     as solvers.  This means that the simplifier can build transitivity chains
   165     to solve goals from the assumptions.
   166   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   167     of blast or auto after simplification become unnecessary because the goal
   168     is solved by simplification already.
   169 
   170 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws, 
   171     all proved in axiomatic type classes for semirings, rings and fields.
   172 
   173 * Numerics:
   174   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   175     now formalized using the Ring_and_Field theory mentioned above. 
   176   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   177     than before, because now they are set up once in a generic manner.
   178   - INCOMPATIBILITY: many type-specific arithmetic laws have gone. 
   179     Look for the general versions in Ring_and_Field (and Power if they concern
   180     exponentiation).
   181 
   182 * Type "rat" of the rational numbers is now available in HOL-Complex.
   183 
   184 * Records:
   185   - Record types are now by default printed with their type abbreviation
   186     instead of the list of all field types. This can be configured via
   187     the reference "print_record_type_abbr".
   188   - Simproc "record_upd_simproc" for simplification of multiple updates added 
   189     (not enabled by default).
   190   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   191     EX x. x = sel r to True (not enabled by default).
   192   - Tactic "record_split_simp_tac" to split and simplify records added.
   193  
   194 * 'specification' command added, allowing for definition by
   195   specification.  There is also an 'ax_specification' command that
   196   introduces the new constants axiomatically.
   197 
   198 * arith(_tac) is now able to generate counterexamples for reals as well.
   199 
   200 * HOL-Algebra: new locale "ring" for non-commutative rings.
   201 
   202 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   203   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   204 
   205 * HOL-Matrix: a first theory for matrices in HOL with an application of 
   206   matrix theory to linear programming.
   207 
   208 * Unions and Intersections:
   209   The x-symbol output syntax of UN and INT has been changed
   210   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   211   i.e. the index formulae has become a subscript, like in normal math.
   212   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   213   The subscript version is also accepted as input syntax.
   214 
   215 * Unions and Intersections over Intervals:
   216   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is 
   217   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A" 
   218   like in normal math, and corresponding versions for < and for intersection.
   219 
   220 * ML: the legacy theory structures Int and List have been removed. They had
   221   conflicted with ML Basis Library structures having the same names.
   222 
   223 * 'refute' command added to search for (finite) countermodels.  Only works
   224   for a fragment of HOL.  The installation of an external SAT solver is
   225   highly recommended.  See "HOL/Refute.thy" for details.
   226 
   227 * 'quickcheck' command: Allows to find counterexamples by evaluating
   228   formulae under an assignment of free variables to random values.
   229   In contrast to 'refute', it can deal with inductive datatypes,
   230   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   231   for examples.
   232 
   233 
   234 *** HOLCF ***
   235 
   236 * Streams now come with concatenation and are part of the HOLCF image
   237 
   238 
   239 
   240 New in Isabelle2003 (May 2003)
   241 ------------------------------
   242 
   243 *** General ***
   244 
   245 * Provers/simplifier:
   246 
   247   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   248     Assumptions are now subject to complete mutual simplification,
   249     not just from left to right. The simplifier now preserves
   250     the order of assumptions.
   251 
   252     Potential INCOMPATIBILITY:
   253 
   254     -- simp sometimes diverges where the old version did
   255        not, e.g. invoking simp on the goal
   256 
   257         [| P (f x); y = x; f x = f y |] ==> Q
   258 
   259        now gives rise to the infinite reduction sequence
   260 
   261         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   262 
   263        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   264        kind of problem.
   265 
   266     -- Tactics combining classical reasoner and simplification (such as auto)
   267        are also affected by this change, because many of them rely on
   268        simp. They may sometimes diverge as well or yield a different numbers
   269        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   270        in case of problems. Sometimes subsequent calls to the classical
   271        reasoner will fail because a preceeding call to the simplifier too
   272        eagerly simplified the goal, e.g. deleted redundant premises.
   273 
   274   - The simplifier trace now shows the names of the applied rewrite rules
   275 
   276   - You can limit the number of recursive invocations of the simplifier
   277     during conditional rewriting (where the simplifie tries to solve the
   278     conditions before applying the rewrite rule):
   279     ML "simp_depth_limit := n"
   280     where n is an integer. Thus you can force termination where previously
   281     the simplifier would diverge.
   282 
   283   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   284 
   285   - No longer aborts on failed congruence proof.  Instead, the
   286     congruence is ignored.
   287 
   288 * Pure: New generic framework for extracting programs from constructive
   289   proofs. See HOL/Extraction.thy for an example instantiation, as well
   290   as HOL/Extraction for some case studies.
   291 
   292 * Pure: The main goal of the proof state is no longer shown by default, only
   293 the subgoals. This behaviour is controlled by a new flag.
   294    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   295 (ML: Proof.show_main_goal).
   296 
   297 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   298 rules whose conclusion matches subgoal 1:
   299       PG menu: Isabelle/Isar -> Show me -> matching rules
   300 The rules are ordered by how closely they match the subgoal.
   301 In particular, rules that solve a subgoal outright are displayed first
   302 (or rather last, the way they are printed).
   303 (ML: ProofGeneral.print_intros())
   304 
   305 * Pure: New flag trace_unify_fail causes unification to print
   306 diagnostic information (PG: in trace buffer) when it fails. This is
   307 useful for figuring out why single step proofs like rule, erule or
   308 assumption failed.
   309 
   310 * Pure: Locale specifications now produce predicate definitions
   311 according to the body of text (covering assumptions modulo local
   312 definitions); predicate "loc_axioms" covers newly introduced text,
   313 while "loc" is cumulative wrt. all included locale expressions; the
   314 latter view is presented only on export into the global theory
   315 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   316 on the old view without predicates;
   317 
   318 * Pure: predefined locales "var" and "struct" are useful for sharing
   319 parameters (as in CASL, for example); just specify something like
   320 ``var x + var y + struct M'' as import;
   321 
   322 * Pure: improved thms_containing: proper indexing of facts instead of
   323 raw theorems; check validity of results wrt. current name space;
   324 include local facts of proof configuration (also covers active
   325 locales), cover fixed variables in index; may use "_" in term
   326 specification; an optional limit for the number of printed facts may
   327 be given (the default is 40);
   328 
   329 * Pure: disallow duplicate fact bindings within new-style theory files
   330 (batch-mode only);
   331 
   332 * Provers: improved induct method: assumptions introduced by case
   333 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   334 the goal statement); "foo" still refers to all facts collectively;
   335 
   336 * Provers: the function blast.overloaded has been removed: all constants
   337 are regarded as potentially overloaded, which improves robustness in exchange
   338 for slight decrease in efficiency;
   339 
   340 * Provers/linorder: New generic prover for transitivity reasoning over
   341 linear orders.  Note: this prover is not efficient!
   342 
   343 * Isar: preview of problems to finish 'show' now produce an error
   344 rather than just a warning (in interactive mode);
   345 
   346 
   347 *** HOL ***
   348 
   349 * arith(_tac)
   350 
   351  - Produces a counter example if it cannot prove a goal.
   352    Note that the counter example may be spurious if the goal is not a formula
   353    of quantifier-free linear arithmetic.
   354    In ProofGeneral the counter example appears in the trace buffer.
   355 
   356  - Knows about div k and mod k where k is a numeral of type nat or int.
   357 
   358  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   359    linear arithmetic fails. This takes account of quantifiers and divisibility.
   360    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   361 
   362 * simp's arithmetic capabilities have been enhanced a bit: it now
   363 takes ~= in premises into account (by performing a case split);
   364 
   365 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   366 are distributed over a sum of terms;
   367 
   368 * New tactic "trans_tac" and method "trans" instantiate
   369 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   370 "<=", "<" and "="). 
   371 
   372 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   373 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   374 
   375 * 'typedef' command has new option "open" to suppress the set
   376 definition;
   377 
   378 * functions Min and Max on finite sets have been introduced (theory
   379 Finite_Set);
   380 
   381 * attribute [symmetric] now works for relations as well; it turns
   382 (x,y) : R^-1 into (y,x) : R, and vice versa;
   383 
   384 * induct over a !!-quantified statement (say !!x1..xn):
   385   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   386 
   387 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   388 %x. None. Warning: empty_def now refers to the previously hidden definition
   389 of the empty set.
   390 
   391 * Algebra: formalization of classical algebra.  Intended as base for
   392 any algebraic development in Isabelle.  Currently covers group theory
   393 (up to Sylow's theorem) and ring theory (Universal Property of
   394 Univariate Polynomials).  Contributions welcome;
   395 
   396 * GroupTheory: deleted, since its material has been moved to Algebra;
   397 
   398 * Complex: new directory of the complex numbers with numeric constants, 
   399 nonstandard complex numbers, and some complex analysis, standard and 
   400 nonstandard (Jacques Fleuriot);
   401 
   402 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   403 
   404 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   405 Fleuriot);
   406 
   407 * Real/HahnBanach: updated and adapted to locales;
   408 
   409 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   410 Gray and Kramer);
   411 
   412 * UNITY: added the Meier-Sanders theory of progress sets;
   413 
   414 * MicroJava: bytecode verifier and lightweight bytecode verifier
   415 as abstract algorithms, instantiated to the JVM;
   416 
   417 * Bali: Java source language formalization. Type system, operational
   418 semantics, axiomatic semantics. Supported language features:
   419 classes, interfaces, objects,virtual methods, static methods,
   420 static/instance fields, arrays, access modifiers, definite
   421 assignment, exceptions.
   422 
   423 
   424 *** ZF ***
   425 
   426 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   427 universe, etc.);
   428 
   429 * Main ZF: virtually all theories converted to new-style format;
   430 
   431 
   432 *** ML ***
   433 
   434 * Pure: Tactic.prove provides sane interface for internal proofs;
   435 omits the infamous "standard" operation, so this is more appropriate
   436 than prove_goalw_cterm in many situations (e.g. in simprocs);
   437 
   438 * Pure: improved error reporting of simprocs;
   439 
   440 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   441 up simprocs;
   442 
   443 
   444 *** Document preparation ***
   445 
   446 * uses \par instead of \\ for line breaks in theory text. This may
   447 shift some page breaks in large documents. To get the old behaviour
   448 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   449 
   450 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   451 other packages
   452 
   453 * \<euro> now needs package babel/greek instead of marvosym (which
   454 broke \Rightarrow)
   455 
   456 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   457 textcomp package)
   458 
   459 
   460 
   461 New in Isabelle2002 (March 2002)
   462 --------------------------------
   463 
   464 *** Document preparation ***
   465 
   466 * greatly simplified document preparation setup, including more
   467 graceful interpretation of isatool usedir -i/-d/-D options, and more
   468 instructive isatool mkdir; users should basically be able to get
   469 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   470 users may run a separate document processing stage manually like this:
   471 "isatool usedir -D output HOL Test && isatool document Test/output";
   472 
   473 * theory dependency graph may now be incorporated into documents;
   474 isatool usedir -g true will produce session_graph.eps/.pdf for use
   475 with \includegraphics of LaTeX;
   476 
   477 * proper spacing of consecutive markup elements, especially text
   478 blocks after section headings;
   479 
   480 * support bold style (for single symbols only), input syntax is like
   481 this: "\<^bold>\<alpha>" or "\<^bold>A";
   482 
   483 * \<bullet> is now output as bold \cdot by default, which looks much
   484 better in printed text;
   485 
   486 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   487 note that these symbols are currently unavailable in Proof General /
   488 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   489 
   490 * isatool latex no longer depends on changed TEXINPUTS, instead
   491 isatool document copies the Isabelle style files to the target
   492 location;
   493 
   494 
   495 *** Isar ***
   496 
   497 * Pure/Provers: improved proof by cases and induction;
   498   - 'case' command admits impromptu naming of parameters (such as
   499     "case (Suc n)");
   500   - 'induct' method divinates rule instantiation from the inductive
   501     claim; no longer requires excessive ?P bindings for proper
   502     instantiation of cases;
   503   - 'induct' method properly enumerates all possibilities of set/type
   504     rules; as a consequence facts may be also passed through *type*
   505     rules without further ado;
   506   - 'induct' method now derives symbolic cases from the *rulified*
   507     rule (before it used to rulify cases stemming from the internal
   508     atomized version); this means that the context of a non-atomic
   509     statement becomes is included in the hypothesis, avoiding the
   510     slightly cumbersome show "PROP ?case" form;
   511   - 'induct' may now use elim-style induction rules without chaining
   512     facts, using ``missing'' premises from the goal state; this allows
   513     rules stemming from inductive sets to be applied in unstructured
   514     scripts, while still benefitting from proper handling of non-atomic
   515     statements; NB: major inductive premises need to be put first, all
   516     the rest of the goal is passed through the induction;
   517   - 'induct' proper support for mutual induction involving non-atomic
   518     rule statements (uses the new concept of simultaneous goals, see
   519     below);
   520   - append all possible rule selections, but only use the first
   521     success (no backtracking);
   522   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   523   - undeclared rule case names default to numbers 1, 2, 3, ...;
   524   - added 'print_induct_rules' (covered by help item in recent Proof
   525     General versions);
   526   - moved induct/cases attributes to Pure, methods to Provers;
   527   - generic method setup instantiated for FOL and HOL;
   528 
   529 * Pure: support multiple simultaneous goal statements, for example
   530 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   531 meta-level mechanism, this acts as if several individual goals had
   532 been stated separately; in particular common proof methods need to be
   533 repeated in order to cover all claims; note that a single elimination
   534 step is *not* sufficient to establish the two conjunctions, so this
   535 fails:
   536 
   537   assume "A & B" then have A and B ..   (*".." fails*)
   538 
   539 better use "obtain" in situations as above; alternative refer to
   540 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   541 
   542 * Pure: proper integration with ``locales''; unlike the original
   543 version by Florian Kammüller, Isar locales package high-level proof
   544 contexts rather than raw logical ones (e.g. we admit to include
   545 attributes everywhere); operations on locales include merge and
   546 rename; support for implicit arguments (``structures''); simultaneous
   547 type-inference over imports and text; see also HOL/ex/Locales.thy for
   548 some examples;
   549 
   550 * Pure: the following commands have been ``localized'', supporting a
   551 target locale specification "(in name)": 'lemma', 'theorem',
   552 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   553 stored both within the locale and at the theory level (exported and
   554 qualified by the locale name);
   555 
   556 * Pure: theory goals may now be specified in ``long'' form, with
   557 ad-hoc contexts consisting of arbitrary locale elements. for example
   558 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   559 definitions may be given, too); the result is a meta-level rule with
   560 the context elements being discharged in the obvious way;
   561 
   562 * Pure: new proof command 'using' allows to augment currently used
   563 facts after a goal statement ('using' is syntactically analogous to
   564 'apply', but acts on the goal's facts only); this allows chained facts
   565 to be separated into parts given before and after a claim, as in
   566 ``from a and b have C using d and e <proof>'';
   567 
   568 * Pure: renamed "antecedent" case to "rule_context";
   569 
   570 * Pure: new 'judgment' command records explicit information about the
   571 object-logic embedding (used by several tools internally); no longer
   572 use hard-wired "Trueprop";
   573 
   574 * Pure: added 'corollary' command;
   575 
   576 * Pure: fixed 'token_translation' command;
   577 
   578 * Pure: removed obsolete 'exported' attribute;
   579 
   580 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   581 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   582 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   583 
   584 * Pure: method 'atomize' presents local goal premises as object-level
   585 statements (atomic meta-level propositions); setup controlled via
   586 rewrite rules declarations of 'atomize' attribute; example
   587 application: 'induct' method with proper rule statements in improper
   588 proof *scripts*;
   589 
   590 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   591 now consider the syntactic context of assumptions, giving a better
   592 chance to get type-inference of the arguments right (this is
   593 especially important for locales);
   594 
   595 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   596 mode;
   597 
   598 * Pure/obtain: the formal conclusion "thesis", being marked as
   599 ``internal'', may no longer be reference directly in the text;
   600 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   601 situations;
   602 
   603 * Pure: generic 'sym' attribute which declares a rule both as pure
   604 'elim?' and for the 'symmetric' operation;
   605 
   606 * Pure: marginal comments ``--'' may now occur just anywhere in the
   607 text; the fixed correlation with particular command syntax has been
   608 discontinued;
   609 
   610 * Pure: new method 'rules' is particularly well-suited for proof
   611 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   612 but often produces more compact proof terms with less detours;
   613 
   614 * Pure/Provers/classical: simplified integration with pure rule
   615 attributes and methods; the classical "intro?/elim?/dest?"
   616 declarations coincide with the pure ones; the "rule" method no longer
   617 includes classically swapped intros; "intro" and "elim" methods no
   618 longer pick rules from the context; also got rid of ML declarations
   619 AddXIs/AddXEs/AddXDs; all of this has some potential for
   620 INCOMPATIBILITY;
   621 
   622 * Provers/classical: attribute 'swapped' produces classical inversions
   623 of introduction rules;
   624 
   625 * Provers/simplifier: 'simplified' attribute may refer to explicit
   626 rules instead of full simplifier context; 'iff' attribute handles
   627 conditional rules;
   628 
   629 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   630 
   631 * HOL: 'recdef' now fails on unfinished automated proofs, use
   632 "(permissive)" option to recover old behavior;
   633 
   634 * HOL: 'inductive' no longer features separate (collective) attributes
   635 for 'intros' (was found too confusing);
   636 
   637 * HOL: properly declared induction rules less_induct and
   638 wf_induct_rule;
   639 
   640 
   641 *** HOL ***
   642 
   643 * HOL: moved over to sane numeral syntax; the new policy is as
   644 follows:
   645 
   646   - 0 and 1 are polymorphic constants, which are defined on any
   647   numeric type (nat, int, real etc.);
   648 
   649   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   650   binary representation internally;
   651 
   652   - type nat has special constructor Suc, and generally prefers Suc 0
   653   over 1::nat and Suc (Suc 0) over 2::nat;
   654 
   655 This change may cause significant problems of INCOMPATIBILITY; here
   656 are some hints on converting existing sources:
   657 
   658   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   659   entities, so expressions involving "-" (unary or binary minus) need
   660   to be spaced properly;
   661 
   662   - existing occurrences of "1" may need to be constraint "1::nat" or
   663   even replaced by Suc 0; similar for old "2";
   664 
   665   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   666 
   667   - remove all special provisions on numerals in proofs;
   668 
   669 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   670 representation (depends on bin_arith_simps in the default context);
   671 
   672 * HOL: symbolic syntax for x^2 (numeral 2);
   673 
   674 * HOL: the class of all HOL types is now called "type" rather than
   675 "term"; INCOMPATIBILITY, need to adapt references to this type class
   676 in axclass/classes, instance/arities, and (usually rare) occurrences
   677 in typings (of consts etc.); internally the class is called
   678 "HOL.type", ML programs should refer to HOLogic.typeS;
   679 
   680 * HOL/record package improvements:
   681   - new derived operations "fields" to build a partial record section,
   682     "extend" to promote a fixed record to a record scheme, and
   683     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   684     declared as simp by default;
   685   - shared operations ("more", "fields", etc.) now need to be always
   686     qualified) --- potential INCOMPATIBILITY;
   687   - removed "make_scheme" operations (use "make" with "extend") --
   688     INCOMPATIBILITY;
   689   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   690   - provides cases/induct rules for use with corresponding Isar
   691     methods (for concrete records, record schemes, concrete more
   692     parts, and schematic more parts -- in that order);
   693   - internal definitions directly based on a light-weight abstract
   694     theory of product types over typedef rather than datatype;
   695 
   696 * HOL: generic code generator for generating executable ML code from
   697 specifications; specific support for HOL constructs such as inductive
   698 datatypes and sets, as well as recursive functions; can be invoked
   699 via 'generate_code' theory section;
   700 
   701 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   702 
   703 * HOL: consolidated and renamed several theories.  In particular:
   704 	Ord.thy has been absorbed into HOL.thy
   705 	String.thy has been absorbed into List.thy
   706  
   707 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   708 (beware of argument permutation!);
   709 
   710 * HOL: linorder_less_split superseded by linorder_cases;
   711 
   712 * HOL/List: "nodups" renamed to "distinct";
   713 
   714 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   715 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   716   - Ex_def has changed, now need to use some_eq_ex
   717 
   718 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   719 in this (rare) case use:
   720 
   721   delSWrapper "split_all_tac"
   722   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   723 
   724 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   725 MAY FAIL;
   726 
   727 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   728 Isabelle's type classes, ^ on functions and relations has too general
   729 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   730 necessary to attach explicit type constraints;
   731 
   732 * HOL/Relation: the prefix name of the infix "O" has been changed from
   733 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   734 renamed accordingly (eg "compI" -> "rel_compI").
   735 
   736 * HOL: syntax translations now work properly with numerals and records
   737 expressions;
   738 
   739 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   740 of "lam" -- INCOMPATIBILITY;
   741 
   742 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   743 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   744 renamed "Product_Type.unit";
   745 
   746 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   747 
   748 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   749 the "cases" method);
   750 
   751 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   752 Florian Kammüller);
   753 
   754 * HOL/IMP: updated and converted to new-style theory format; several
   755 parts turned into readable document, with proper Isar proof texts and
   756 some explanations (by Gerwin Klein);
   757 
   758 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   759 
   760 * HOL-Hyperreal is now a logic image;
   761 
   762 
   763 *** HOLCF ***
   764 
   765 * Isar: consts/constdefs supports mixfix syntax for continuous
   766 operations;
   767 
   768 * Isar: domain package adapted to new-style theory format, e.g. see
   769 HOLCF/ex/Dnat.thy;
   770 
   771 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   772 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   773 lift.induct_tac, always use UU instead of Undef;
   774 
   775 * HOLCF/IMP: updated and converted to new-style theory;
   776 
   777 
   778 *** ZF ***
   779 
   780 * Isar: proper integration of logic-specific tools and packages,
   781 including theory commands '(co)inductive', '(co)datatype',
   782 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   783 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   784 
   785 * theory Main no longer includes AC; for the Axiom of Choice, base
   786 your theory on Main_ZFC;
   787 
   788 * the integer library now covers quotients and remainders, with many
   789 laws relating division to addition, multiplication, etc.;
   790 
   791 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   792 typeless version of the formalism;
   793 
   794 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   795 format;
   796 
   797 * ZF/Induct: new directory for examples of inductive definitions,
   798 including theory Multiset for multiset orderings; converted to
   799 new-style theory format;
   800 
   801 * ZF: many new theorems about lists, ordinals, etc.;
   802 
   803 
   804 *** General ***
   805 
   806 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   807 variable proof controls level of detail: 0 = no proofs (only oracle
   808 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   809 also ref manual for further ML interfaces;
   810 
   811 * Pure/axclass: removed obsolete ML interface
   812 goal_subclass/goal_arity;
   813 
   814 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   815 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   816 separate tokens, so expressions involving minus need to be spaced
   817 properly;
   818 
   819 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   820 rather than "infixl" or "infixr";
   821 
   822 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   823 sort constraint specifications in type inference; e.g. "x::_::foo"
   824 ensures that the type of "x" is of sort "foo" (but not necessarily a
   825 type variable);
   826 
   827 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   828 control output of nested => (types); the default behavior is
   829 "type_brackets";
   830 
   831 * Pure/syntax: builtin parse translation for "_constify" turns valued
   832 tokens into AST constants;
   833 
   834 * Pure/syntax: prefer later declarations of translations and print
   835 translation functions; potential INCOMPATIBILITY: need to reverse
   836 multiple declarations for same syntax element constant;
   837 
   838 * Pure/show_hyps reset by default (in accordance to existing Isar
   839 practice);
   840 
   841 * Provers/classical: renamed addaltern to addafter, addSaltern to
   842 addSafter;
   843 
   844 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   845 as well;
   846 
   847 * system: tested support for MacOS X; should be able to get Isabelle +
   848 Proof General to work in a plain Terminal after installing Poly/ML
   849 (e.g. from the Isabelle distribution area) and GNU bash alone
   850 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   851 support requires further installations, e.g. from
   852 http://fink.sourceforge.net/);
   853 
   854 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   855 
   856 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   857 of 40 MB), cf. ML_OPTIONS;
   858 
   859 * system: Proof General keywords specification is now part of the
   860 Isabelle distribution (see etc/isar-keywords.el);
   861 
   862 * system: support for persistent Proof General sessions (refrain from
   863 outdating all loaded theories on startup); user may create writable
   864 logic images like this: ``isabelle -q HOL Test'';
   865 
   866 * system: smart selection of Isabelle process versus Isabelle
   867 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   868 run both "isabelle" and "Isabelle" even if file names are badly
   869 damaged (executable inspects the case of the first letter of its own
   870 name); added separate "isabelle-process" and "isabelle-interface";
   871 
   872 * system: refrain from any attempt at filtering input streams; no
   873 longer support ``8bit'' encoding of old isabelle font, instead proper
   874 iso-latin characters may now be used; the related isatools
   875 "symbolinput" and "nonascii" have disappeared as well;
   876 
   877 * system: removed old "xterm" interface (the print modes "xterm" and
   878 "xterm_color" are still available for direct use in a suitable
   879 terminal);
   880 
   881 
   882 
   883 New in Isabelle99-2 (February 2001)
   884 -----------------------------------
   885 
   886 *** Overview of INCOMPATIBILITIES ***
   887 
   888 * HOL: please note that theories in the Library and elsewhere often use the
   889 new-style (Isar) format; to refer to their theorems in an ML script you must
   890 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   891 
   892 * HOL: inductive package no longer splits induction rule aggressively,
   893 but only as far as specified by the introductions given; the old
   894 format may be recovered via ML function complete_split_rule or attribute
   895 'split_rule (complete)';
   896 
   897 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   898 gfp_Tarski to gfp_unfold;
   899 
   900 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   901 
   902 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   903 relation); infix "^^" has been renamed "``"; infix "``" has been
   904 renamed "`"; "univalent" has been renamed "single_valued";
   905 
   906 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   907 operation;
   908 
   909 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   910 
   911 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   912 
   913 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   914 consequence, it is no longer monotonic wrt. the local goal context
   915 (which is now passed through the inductive cases);
   916 
   917 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   918 \<gg> to \<ggreater>;
   919 
   920 
   921 *** Document preparation ***
   922 
   923 * \isabellestyle{NAME} selects version of Isabelle output (currently
   924 available: are "it" for near math-mode best-style output, "sl" for
   925 slanted text style, and "tt" for plain type-writer; if no
   926 \isabellestyle command is given, output is according to slanted
   927 type-writer);
   928 
   929 * support sub/super scripts (for single symbols only), input syntax is
   930 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   931 
   932 * some more standard symbols; see Appendix A of the system manual for
   933 the complete list of symbols defined in isabellesym.sty;
   934 
   935 * improved isabelle style files; more abstract symbol implementation
   936 (should now use \isamath{...} and \isatext{...} in custom symbol
   937 definitions);
   938 
   939 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   940 state; Note that presentation of goal states does not conform to
   941 actual human-readable proof documents.  Please do not include goal
   942 states into document output unless you really know what you are doing!
   943 
   944 * proper indentation of antiquoted output with proportional LaTeX
   945 fonts;
   946 
   947 * no_document ML operator temporarily disables LaTeX document
   948 generation;
   949 
   950 * isatool unsymbolize tunes sources for plain ASCII communication;
   951 
   952 
   953 *** Isar ***
   954 
   955 * Pure: Isar now suffers initial goal statements to contain unbound
   956 schematic variables (this does not conform to actual readable proof
   957 documents, due to unpredictable outcome and non-compositional proof
   958 checking); users who know what they are doing may use schematic goals
   959 for Prolog-style synthesis of proven results;
   960 
   961 * Pure: assumption method (an implicit finishing) now handles actual
   962 rules as well;
   963 
   964 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   965 initial goal, declare "that" only as Pure intro (only for single
   966 steps); the "that" rule assumption may now be involved in implicit
   967 finishing, thus ".." becomes a feasible for trivial obtains;
   968 
   969 * Pure: default proof step now includes 'intro_classes'; thus trivial
   970 instance proofs may be performed by "..";
   971 
   972 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   973 statements as well;
   974 
   975 * Pure: more robust selection of calculational rules;
   976 
   977 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   978 rule (as well as the assumption rule);
   979 
   980 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   981 lemmas, using the graph browser tool;
   982 
   983 * Pure: predict failure of "show" in interactive mode;
   984 
   985 * Pure: 'thms_containing' now takes actual terms as arguments;
   986 
   987 * HOL: improved method 'induct' --- now handles non-atomic goals
   988 (potential INCOMPATIBILITY); tuned error handling;
   989 
   990 * HOL: cases and induct rules now provide explicit hints about the
   991 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   992 any remaining facts are inserted into the goal verbatim;
   993 
   994 * HOL: local contexts (aka cases) may now contain term bindings as
   995 well; the 'cases' and 'induct' methods new provide a ?case binding for
   996 the result to be shown in each case;
   997 
   998 * HOL: added 'recdef_tc' command;
   999 
  1000 * isatool convert assists in eliminating legacy ML scripts;
  1001 
  1002 
  1003 *** HOL ***
  1004 
  1005 * HOL/Library: a collection of generic theories to be used together
  1006 with main HOL; the theory loader path already includes this directory
  1007 by default; the following existing theories have been moved here:
  1008 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1009 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1010 
  1011 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1012 modelling and verification task performed in Isabelle/HOL +
  1013 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1014 
  1015 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1016 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1017 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1018 'domain', this makes the theory consistent with mathematical
  1019 literature;
  1020 
  1021 * HOL basics: added overloaded operations "inverse" and "divide"
  1022 (infix "/"), syntax for generic "abs" operation, generic summation
  1023 operator \<Sum>;
  1024 
  1025 * HOL/typedef: simplified package, provide more useful rules (see also
  1026 HOL/subset.thy);
  1027 
  1028 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1029 now expressed as a proper nested rule (old-style tactic scripts may
  1030 require atomize_strip_tac to cope with non-atomic premises);
  1031 
  1032 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1033 to "split_conv" (old name still available for compatibility);
  1034 
  1035 * HOL: improved concrete syntax for strings (e.g. allows translation
  1036 rules with string literals);
  1037 
  1038 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1039  and Fleuriot's mechanization of analysis, including the transcendental
  1040  functions for the reals;
  1041 
  1042 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1043 
  1044 
  1045 *** CTT ***
  1046 
  1047 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1048 "lam" is displayed as TWO lambda-symbols
  1049 
  1050 * CTT: theory Main now available, containing everything (that is, Bool
  1051 and Arith);
  1052 
  1053 
  1054 *** General ***
  1055 
  1056 * Pure: the Simplifier has been implemented properly as a derived rule
  1057 outside of the actual kernel (at last!); the overall performance
  1058 penalty in practical applications is about 50%, while reliability of
  1059 the Isabelle inference kernel has been greatly improved;
  1060 
  1061 * print modes "brackets" and "no_brackets" control output of nested =>
  1062 (types) and ==> (props); the default behaviour is "brackets";
  1063 
  1064 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1065 as assumptions as well;
  1066 
  1067 * system: support Poly/ML 4.0;
  1068 
  1069 * system: isatool install handles KDE version 1 or 2;
  1070 
  1071 
  1072 
  1073 New in Isabelle99-1 (October 2000)
  1074 ----------------------------------
  1075 
  1076 *** Overview of INCOMPATIBILITIES ***
  1077 
  1078 * HOL: simplification of natural numbers is much changed; to partly
  1079 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1080 issue the following ML commands:
  1081 
  1082   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1083   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1084 
  1085 * HOL: simplification no longer dives into case-expressions; this is
  1086 controlled by "t.weak_case_cong" for each datatype t;
  1087 
  1088 * HOL: nat_less_induct renamed to less_induct;
  1089 
  1090 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1091 fixsome to patch .thy and .ML sources automatically;
  1092 
  1093   select_equality  -> some_equality
  1094   select_eq_Ex     -> some_eq_ex
  1095   selectI2EX       -> someI2_ex
  1096   selectI2         -> someI2
  1097   selectI          -> someI
  1098   select1_equality -> some1_equality
  1099   Eps_sym_eq       -> some_sym_eq_trivial
  1100   Eps_eq           -> some_eq_trivial
  1101 
  1102 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1103 
  1104 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1105 instead);
  1106 
  1107 * HOL: the recursion equations generated by 'recdef' are now called
  1108 f.simps instead of f.rules;
  1109 
  1110 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1111 
  1112 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1113 sometimes be needed;
  1114 
  1115 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1116 
  1117 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1118 
  1119 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1120 product is now "<*>" instead of "Times"; the lexicographic product is
  1121 now "<*lex*>" instead of "**";
  1122 
  1123 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1124 of main HOL, but was unused); better use HOL's datatype package;
  1125 
  1126 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1127 the old syntax may be recovered as follows:
  1128 
  1129   syntax (symbols)
  1130     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1131       (infixl "\\<oplus>" 100)
  1132 
  1133 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1134 
  1135 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1136 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1137 internally;
  1138 
  1139 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1140 changed from A/r to A//r;
  1141 
  1142 * ZF: new treatment of arithmetic (nat & int) may break some old
  1143 proofs;
  1144 
  1145 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1146 rulify -> rule_format, elimify -> elim_format, ...);
  1147 
  1148 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1149 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1150 should have to change intro!! to intro? only); replaced "delrule" by
  1151 "rule del";
  1152 
  1153 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1154 
  1155 * Provers: strengthened force_tac by using new first_best_tac;
  1156 
  1157 * LaTeX document preparation: several changes of isabelle.sty (see
  1158 lib/texinputs);
  1159 
  1160 
  1161 *** Document preparation ***
  1162 
  1163 * formal comments (text blocks etc.) in new-style theories may now
  1164 contain antiquotations of thm/prop/term/typ/text to be presented
  1165 according to latex print mode; concrete syntax is like this:
  1166 @{term[show_types] "f(x) = a + x"};
  1167 
  1168 * isatool mkdir provides easy setup of Isabelle session directories,
  1169 including proper document sources;
  1170 
  1171 * generated LaTeX sources are now deleted after successful run
  1172 (isatool document -c); may retain a copy somewhere else via -D option
  1173 of isatool usedir;
  1174 
  1175 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1176 style files, achieving self-contained LaTeX sources and simplifying
  1177 LaTeX debugging;
  1178 
  1179 * old-style theories now produce (crude) LaTeX output as well;
  1180 
  1181 * browser info session directories are now self-contained (may be put
  1182 on WWW server seperately); improved graphs of nested sessions; removed
  1183 graph for 'all sessions';
  1184 
  1185 * several improvements in isabelle style files; \isabellestyle{it}
  1186 produces fake math mode output; \isamarkupheader is now \section by
  1187 default; see lib/texinputs/isabelle.sty etc.;
  1188 
  1189 
  1190 *** Isar ***
  1191 
  1192 * Isar/Pure: local results and corresponding term bindings are now
  1193 subject to Hindley-Milner polymorphism (similar to ML); this
  1194 accommodates incremental type-inference very nicely;
  1195 
  1196 * Isar/Pure: new derived language element 'obtain' supports
  1197 generalized existence reasoning;
  1198 
  1199 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1200 support accumulation of results, without applying any rules yet;
  1201 useful to collect intermediate results without explicit name
  1202 references, and for use with transitivity rules with more than 2
  1203 premises;
  1204 
  1205 * Isar/Pure: scalable support for case-analysis type proofs: new
  1206 'case' language element refers to local contexts symbolically, as
  1207 produced by certain proof methods; internally, case names are attached
  1208 to theorems as "tags";
  1209 
  1210 * Isar/Pure: theory command 'hide' removes declarations from
  1211 class/type/const name spaces;
  1212 
  1213 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1214 indicate potential overloading;
  1215 
  1216 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1217 
  1218 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1219 "{a,b,c}" instead of {a,b,c};
  1220 
  1221 * Isar/Pure now provides its own version of intro/elim/dest
  1222 attributes; useful for building new logics, but beware of confusion
  1223 with the version in Provers/classical;
  1224 
  1225 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1226 case name 'antecedent';
  1227 
  1228 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1229 to the current context is now done automatically);
  1230 
  1231 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1232 for definining proof methods in ML;
  1233 
  1234 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1235 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1236 most cases, one should have to change intro!! to intro? only);
  1237 replaced "delrule" by "rule del";
  1238 
  1239 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1240 'symmetric' attribute (the latter supercedes [RS sym]);
  1241 
  1242 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1243 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1244 well (including splits);
  1245 
  1246 * Isar/Provers: Simplifier and Classical methods now support all kind
  1247 of modifiers used in the past, including 'cong', 'iff', etc.
  1248 
  1249 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1250 of Simplifier and Classical reasoner);
  1251 
  1252 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1253 now support named cases; major packages (inductive, datatype, primrec,
  1254 recdef) support case names and properly name parameters;
  1255 
  1256 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1257 monotonicity conditions are extracted to be proven at end of
  1258 calculations;
  1259 
  1260 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1261 method anyway;
  1262 
  1263 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1264 split_if split_if_asm; datatype package provides theorems foo.splits =
  1265 foo.split foo.split_asm for each datatype;
  1266 
  1267 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1268 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1269 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1270 use "(cases (simplified))" method in proper proof texts);
  1271 
  1272 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1273 
  1274 * Isar: names of theorems etc. may be natural numbers as well;
  1275 
  1276 * Isar: 'pr' command: optional arguments for goals_limit and
  1277 ProofContext.prems_limit; no longer prints theory contexts, but only
  1278 proof states;
  1279 
  1280 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1281 additional print modes to be specified; e.g. "pr(latex)" will print
  1282 proof state according to the Isabelle LaTeX style;
  1283 
  1284 * Isar: improved support for emulating tactic scripts, including proof
  1285 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1286 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1287 (for HOL datatypes);
  1288 
  1289 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1290 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1291 'proof method scripts' have to be in depth-first order;
  1292 
  1293 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1294 
  1295 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1296 should instead use individual commands for printing items
  1297 (print_commands, print_methods etc.);
  1298 
  1299 * Isar: added 'nothing' --- the empty list of theorems;
  1300 
  1301 
  1302 *** HOL ***
  1303 
  1304 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1305 corresponding virtual machine and a specification of its bytecode
  1306 verifier and a lightweight bytecode verifier, including proofs of
  1307 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1308 Cornelia Pusch (see also the homepage of project Bali at
  1309 http://isabelle.in.tum.de/Bali/);
  1310 
  1311 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1312 Clemens Ballarin;
  1313 
  1314 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1315 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1316 Rasmussen;
  1317 
  1318 * HOL/Lattice: fundamental concepts of lattice theory and order
  1319 structures, including duals, properties of bounds versus algebraic
  1320 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1321 Theorem for complete lattices etc.; may also serve as a demonstration
  1322 for abstract algebraic reasoning using axiomatic type classes, and
  1323 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1324 
  1325 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1326 von Oheimb;
  1327 
  1328 * HOL/IMPP: extension of IMP with local variables and mutually
  1329 recursive procedures, by David von Oheimb;
  1330 
  1331 * HOL/Lambda: converted into new-style theory and document;
  1332 
  1333 * HOL/ex/Multiquote: example of multiple nested quotations and
  1334 anti-quotations -- basically a generalized version of de-Bruijn
  1335 representation; very useful in avoiding lifting of operations;
  1336 
  1337 * HOL/record: added general record equality rule to simpset; fixed
  1338 select-update simplification procedure to handle extended records as
  1339 well; admit "r" as field name;
  1340 
  1341 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1342 other numeric types and also as the identity of groups, rings, etc.;
  1343 
  1344 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1345 Types nat and int belong to this axclass;
  1346 
  1347 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1348    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1349    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1350   two terms #m*u and #n*u are replaced by #(m+n)*u
  1351     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1352   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1353     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1354 
  1355 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1356 powerful prover for predicate logic but knows nothing of clasets; see
  1357 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1358 
  1359 * HOL: new version of "case_tac" subsumes both boolean case split and
  1360 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1361 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1362 
  1363 * HOL: simplification no longer dives into case-expressions: only the
  1364 selector expression is simplified, but not the remaining arms; to
  1365 enable full simplification of case-expressions for datatype t, you may
  1366 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1367 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1368 
  1369 * HOL/recdef: the recursion equations generated by 'recdef' for
  1370 function 'f' are now called f.simps instead of f.rules; if all
  1371 termination conditions are proved automatically, these simplification
  1372 rules are added to the simpset, as in primrec; rules may be named
  1373 individually as well, resulting in a separate list of theorems for
  1374 each equation;
  1375 
  1376 * HOL/While is a new theory that provides a while-combinator. It
  1377 permits the definition of tail-recursive functions without the
  1378 provision of a termination measure. The latter is necessary once the
  1379 invariant proof rule for while is applied.
  1380 
  1381 * HOL: new (overloaded) notation for the set of elements below/above
  1382 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1383 
  1384 * HOL: theorems impI, allI, ballI bound as "strip";
  1385 
  1386 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1387 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1388 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1389 
  1390 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1391 
  1392 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1393 main HOL, but was unused);
  1394 
  1395 * HOL: fewer consts declared as global (e.g. have to refer to
  1396 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1397 
  1398 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1399 in case of overlap with user translations (e.g. judgements over
  1400 tuples); (note that the underlying logical represenation is still
  1401 bogus);
  1402 
  1403 
  1404 *** ZF ***
  1405 
  1406 * ZF: simplification automatically cancels common terms in arithmetic
  1407 expressions over nat and int;
  1408 
  1409 * ZF: new treatment of nat to minimize type-checking: all operators
  1410 coerce their operands to a natural number using the function natify,
  1411 making the algebraic laws unconditional;
  1412 
  1413 * ZF: as above, for int: operators coerce their operands to an integer
  1414 using the function intify;
  1415 
  1416 * ZF: the integer library now contains many of the usual laws for the
  1417 orderings, including $<=, and monotonicity laws for $+ and $*;
  1418 
  1419 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1420 simplification;
  1421 
  1422 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1423 to the simplifier and classical reasoner simultaneously;
  1424 
  1425 
  1426 *** General ***
  1427 
  1428 * Provers: blast_tac now handles actual object-logic rules as
  1429 assumptions; note that auto_tac uses blast_tac internally as well;
  1430 
  1431 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1432 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1433 
  1434 * Provers: delrules now handles destruct rules as well (no longer need
  1435 explicit make_elim);
  1436 
  1437 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1438   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1439 use instead the strong form,
  1440   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1441 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1442 from destruct-rules;
  1443 
  1444 * Provers: Simplifier.easy_setup provides a fast path to basic
  1445 Simplifier setup for new object-logics;
  1446 
  1447 * Pure: AST translation rules no longer require constant head on LHS;
  1448 
  1449 * Pure: improved name spaces: ambiguous output is qualified; support
  1450 for hiding of names;
  1451 
  1452 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1453 XSYMBOL_HOME; no longer need to do manual configuration in most
  1454 situations;
  1455 
  1456 * system: compression of ML heaps images may now be controlled via -c
  1457 option of isabelle and isatool usedir (currently only observed by
  1458 Poly/ML);
  1459 
  1460 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1461 useful for remote X11);
  1462 
  1463 * system: provide TAGS file for Isabelle sources;
  1464 
  1465 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1466 order;
  1467 
  1468 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1469 timing flag supersedes proof_timing and Toplevel.trace;
  1470 
  1471 * ML: new combinators |>> and |>>> for incremental transformations
  1472 with secondary results (e.g. certain theory extensions):
  1473 
  1474 * ML: PureThy.add_defs gets additional argument to indicate potential
  1475 overloading (usually false);
  1476 
  1477 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1478 results;
  1479 
  1480 
  1481 
  1482 New in Isabelle99 (October 1999)
  1483 --------------------------------
  1484 
  1485 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1486 
  1487 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1488 are no longer simplified.  (This allows the simplifier to unfold recursive
  1489 functional programs.)  To restore the old behaviour, declare
  1490 
  1491     Delcongs [if_weak_cong];
  1492 
  1493 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1494 complement;
  1495 
  1496 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1497 
  1498 * HOL/datatype: mutual_induct_tac no longer exists --
  1499   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1500 
  1501 * HOL/typedef: fixed type inference for representing set; type
  1502 arguments now have to occur explicitly on the rhs as type constraints;
  1503 
  1504 * ZF: The con_defs part of an inductive definition may no longer refer
  1505 to constants declared in the same theory;
  1506 
  1507 * HOL, ZF: the function mk_cases, generated by the inductive
  1508 definition package, has lost an argument.  To simplify its result, it
  1509 uses the default simpset instead of a supplied list of theorems.
  1510 
  1511 * HOL/List: the constructors of type list are now Nil and Cons;
  1512 
  1513 * Simplifier: the type of the infix ML functions
  1514         setSSolver addSSolver setSolver addSolver
  1515 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1516 for packaging solvers. A solver is created via
  1517         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1518 where the string argument is only a comment.
  1519 
  1520 
  1521 *** Proof tools ***
  1522 
  1523 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1524 decision procedure for linear arithmetic. Currently it is used for
  1525 types `nat', `int', and `real' in HOL (see below); it can, should and
  1526 will be instantiated for other types and logics as well.
  1527 
  1528 * The simplifier now accepts rewrite rules with flexible heads, eg
  1529      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1530   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1531   matching.
  1532 
  1533 
  1534 *** General ***
  1535 
  1536 * New Isabelle/Isar subsystem provides an alternative to traditional
  1537 tactical theorem proving; together with the ProofGeneral/isar user
  1538 interface it offers an interactive environment for developing human
  1539 readable proof documents (Isar == Intelligible semi-automated
  1540 reasoning); for further information see isatool doc isar-ref,
  1541 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1542 
  1543 * improved and simplified presentation of theories: better HTML markup
  1544 (including colors), graph views in several sizes; isatool usedir now
  1545 provides a proper interface for user theories (via -P option); actual
  1546 document preparation based on (PDF)LaTeX is available as well (for
  1547 new-style theories only); see isatool doc system for more information;
  1548 
  1549 * native support for Proof General, both for classic Isabelle and
  1550 Isabelle/Isar;
  1551 
  1552 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1553 using the graph browser tool;
  1554 
  1555 * Isabelle manuals now also available as PDF;
  1556 
  1557 * theory loader rewritten from scratch (may not be fully
  1558 bug-compatible); old loadpath variable has been replaced by show_path,
  1559 add_path, del_path, reset_path functions; new operations such as
  1560 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1561 isatool doc ref);
  1562 
  1563 * improved isatool install: option -k creates KDE application icon,
  1564 option -p DIR installs standalone binaries;
  1565 
  1566 * added ML_PLATFORM setting (useful for cross-platform installations);
  1567 more robust handling of platform specific ML images for SML/NJ;
  1568 
  1569 * the settings environment is now statically scoped, i.e. it is never
  1570 created again in sub-processes invoked from isabelle, isatool, or
  1571 Isabelle;
  1572 
  1573 * path element specification '~~' refers to '$ISABELLE_HOME';
  1574 
  1575 * in locales, the "assumes" and "defines" parts may be omitted if
  1576 empty;
  1577 
  1578 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1579 long arrows);
  1580 
  1581 * new print_mode "HTML";
  1582 
  1583 * new flag show_tags controls display of tags of theorems (which are
  1584 basically just comments that may be attached by some tools);
  1585 
  1586 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1587 mode and goal output format:
  1588 
  1589 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1590 244c244
  1591 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1592 ---
  1593 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1594 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1595 181c181
  1596 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1597 ---
  1598 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1599 
  1600 * function bind_thms stores lists of theorems (cf. bind_thm);
  1601 
  1602 * new shorthand tactics ftac, eatac, datac, fatac;
  1603 
  1604 * qed (and friends) now accept "" as result name; in that case the
  1605 theorem is not stored, but proper checks and presentation of the
  1606 result still apply;
  1607 
  1608 * theorem database now also indexes constants "Trueprop", "all",
  1609 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1610 
  1611 
  1612 *** HOL ***
  1613 
  1614 ** HOL arithmetic **
  1615 
  1616 * There are now decision procedures for linear arithmetic over nat and
  1617 int:
  1618 
  1619 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1620 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1621 are treated as atomic; subformulae not involving type `nat' or `int'
  1622 are ignored; quantified subformulae are ignored unless they are
  1623 positive universal or negative existential. The tactic has to be
  1624 invoked by hand and can be a little bit slow. In particular, the
  1625 running time is exponential in the number of occurrences of `min' and
  1626 `max', and `-' on `nat'.
  1627 
  1628 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1629 (negated) (in)equalities among the premises and the conclusion into
  1630 account (i.e. no compound formulae) and does not know about `min' and
  1631 `max', and `-' on `nat'. It is fast and is used automatically by the
  1632 simplifier.
  1633 
  1634 NB: At the moment, these decision procedures do not cope with mixed
  1635 nat/int formulae where the two parts interact, such as `m < n ==>
  1636 int(m) < int(n)'.
  1637 
  1638 * HOL/Numeral provides a generic theory of numerals (encoded
  1639 efficiently as bit strings); setup for types nat/int/real is in place;
  1640 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1641 int, existing theories and proof scripts may require a few additional
  1642 type constraints;
  1643 
  1644 * integer division and remainder can now be performed on constant
  1645 arguments;
  1646 
  1647 * many properties of integer multiplication, division and remainder
  1648 are now available;
  1649 
  1650 * An interface to the Stanford Validity Checker (SVC) is available through the
  1651 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1652 are proved automatically.  SVC must be installed separately, and its results
  1653 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1654 invocation of the underlying oracle).  For SVC see
  1655   http://verify.stanford.edu/SVC
  1656 
  1657 * IsaMakefile: the HOL-Real target now builds an actual image;
  1658 
  1659 
  1660 ** HOL misc **
  1661 
  1662 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1663 (in Isabelle/Isar) -- by Gertrud Bauer;
  1664 
  1665 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1666 analysis for assembly languages with subtypes;
  1667 
  1668 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1669 -- avoids syntactic ambiguities and treats state, transition, and
  1670 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1671 changed syntax and (many) tactics;
  1672 
  1673 * HOL/inductive: Now also handles more general introduction rules such
  1674   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1675   theorems are now maintained within the theory (maintained via the
  1676   "mono" attribute);
  1677 
  1678 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1679   (using function types) such as
  1680 
  1681   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1682 
  1683 * HOL/record: record_simproc (part of the default simpset) takes care
  1684 of selectors applied to updated records; record_split_tac is no longer
  1685 part of the default claset; update_defs may now be removed from the
  1686 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1687 
  1688   claset_ref () := claset() addSWrapper record_split_wrapper;
  1689   Delsimprocs [record_simproc]
  1690 
  1691 * HOL/typedef: fixed type inference for representing set; type
  1692 arguments now have to occur explicitly on the rhs as type constraints;
  1693 
  1694 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1695 names rather than an ML expression;
  1696 
  1697 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1698 supplied later.  Program schemes can be defined, such as
  1699     "While B C s = (if B s then While B C (C s) else s)"
  1700 where the well-founded relation can be chosen after B and C have been given.
  1701 
  1702 * HOL/List: the constructors of type list are now Nil and Cons;
  1703 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1704 course, ML tools referring to List.list.op # etc. have to be adapted;
  1705 
  1706 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1707 disabled by default; run isabelle with option -m HOL to get back to
  1708 the original Gordon/HOL-style output;
  1709 
  1710 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1711 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1712 
  1713 * HOL basic syntax simplified (more orthogonal): all variants of
  1714 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1715 Eps operator is provided as well: "SOME x. P[x]";
  1716 
  1717 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1718 
  1719 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1720 thus available for user theories;
  1721 
  1722 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1723 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1724 time;
  1725 
  1726 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1727 several times and then mp;
  1728 
  1729 
  1730 *** LK ***
  1731 
  1732 * the notation <<...>> is now available as a notation for sequences of
  1733 formulas;
  1734 
  1735 * the simplifier is now installed
  1736 
  1737 * the axiom system has been generalized (thanks to Soren Heilmann)
  1738 
  1739 * the classical reasoner now has a default rule database
  1740 
  1741 
  1742 *** ZF ***
  1743 
  1744 * new primrec section allows primitive recursive functions to be given
  1745 directly (as in HOL) over datatypes and the natural numbers;
  1746 
  1747 * new tactics induct_tac and exhaust_tac for induction (or case
  1748 analysis) over datatypes and the natural numbers;
  1749 
  1750 * the datatype declaration of type T now defines the recursor T_rec;
  1751 
  1752 * simplification automatically does freeness reasoning for datatype
  1753 constructors;
  1754 
  1755 * automatic type-inference, with AddTCs command to insert new
  1756 type-checking rules;
  1757 
  1758 * datatype introduction rules are now added as Safe Introduction rules
  1759 to the claset;
  1760 
  1761 * the syntax "if P then x else y" is now available in addition to
  1762 if(P,x,y);
  1763 
  1764 
  1765 *** Internal programming interfaces ***
  1766 
  1767 * tuned simplifier trace output; new flag debug_simp;
  1768 
  1769 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1770 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1771 
  1772 * AxClass.axclass_tac lost the theory argument;
  1773 
  1774 * tuned current_goals_markers semantics: begin / end goal avoids
  1775 printing empty lines;
  1776 
  1777 * removed prs and prs_fn hook, which was broken because it did not
  1778 include \n in its semantics, forcing writeln to add one
  1779 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1780 string -> unit if you really want to output text without newline;
  1781 
  1782 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1783 plain output, interface builders may have to enable 'isabelle_font'
  1784 mode to get Isabelle font glyphs as before;
  1785 
  1786 * refined token_translation interface; INCOMPATIBILITY: output length
  1787 now of type real instead of int;
  1788 
  1789 * theory loader actions may be traced via new ThyInfo.add_hook
  1790 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1791 your own database of information attached to *whole* theories -- as
  1792 opposed to intra-theory data slots offered via TheoryDataFun;
  1793 
  1794 * proper handling of dangling sort hypotheses (at last!);
  1795 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1796 extra sort hypotheses that can be witnessed from the type signature;
  1797 the force_strip_shyps flag is gone, any remaining shyps are simply
  1798 left in the theorem (with a warning issued by strip_shyps_warning);
  1799 
  1800 
  1801 
  1802 New in Isabelle98-1 (October 1998)
  1803 ----------------------------------
  1804 
  1805 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1806 
  1807 * several changes of automated proof tools;
  1808 
  1809 * HOL: major changes to the inductive and datatype packages, including
  1810 some minor incompatibilities of theory syntax;
  1811 
  1812 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1813 called `inj_on';
  1814 
  1815 * HOL: removed duplicate thms in Arith:
  1816   less_imp_add_less  should be replaced by  trans_less_add1
  1817   le_imp_add_le      should be replaced by  trans_le_add1
  1818 
  1819 * HOL: unary minus is now overloaded (new type constraints may be
  1820 required);
  1821 
  1822 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1823 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1824 now taken as an integer constant.
  1825 
  1826 * Pure: ML function 'theory_of' renamed to 'theory';
  1827 
  1828 
  1829 *** Proof tools ***
  1830 
  1831 * Simplifier:
  1832   1. Asm_full_simp_tac is now more aggressive.
  1833      1. It will sometimes reorient premises if that increases their power to
  1834         simplify.
  1835      2. It does no longer proceed strictly from left to right but may also
  1836         rotate premises to achieve further simplification.
  1837      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1838      old Asm_full_simp_tac in that it does not rotate premises.
  1839   2. The simplifier now knows a little bit about nat-arithmetic.
  1840 
  1841 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1842 allows for selected deletion of wrappers, by introduction of names for
  1843 wrapper functionals.  This implies that addbefore, addSbefore,
  1844 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1845 and that adding two tactics with the same name overwrites the first
  1846 one (emitting a warning).
  1847   type wrapper = (int -> tactic) -> (int -> tactic)
  1848   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1849   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1850   delWrapper, delSWrapper: claset *  string            -> claset
  1851   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1852 
  1853 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1854 semantics; addbefore now affects only the unsafe part of step_tac
  1855 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1856 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1857 by Force_tac;
  1858 
  1859 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1860 compWrapper; added safe wrapper (and access functions for it);
  1861 
  1862 * HOL/split_all_tac is now much faster and fails if there is nothing
  1863 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1864 and the names of the automatically generated variables have changed.
  1865 split_all_tac has moved within claset() from unsafe wrappers to safe
  1866 wrappers, which means that !!-bound variables are split much more
  1867 aggressively, and safe_tac and clarify_tac now split such variables.
  1868 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1869 Note: the same holds for record_split_tac, which does the job of
  1870 split_all_tac for record fields.
  1871 
  1872 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1873 permanently to the default simpset using Addsplits just like
  1874 Addsimps. They can be removed via Delsplits just like
  1875 Delsimps. Lower-case versions are also available.
  1876 
  1877 * HOL/Simplifier: The rule split_if is now part of the default
  1878 simpset. This means that the simplifier will eliminate all occurrences
  1879 of if-then-else in the conclusion of a goal. To prevent this, you can
  1880 either remove split_if completely from the default simpset by
  1881 `Delsplits [split_if]' or remove it in a specific call of the
  1882 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1883 other case splitting rules to/from the default simpset: every datatype
  1884 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1885 t is the name of the datatype).
  1886 
  1887 * Classical reasoner / Simplifier combination: new force_tac (and
  1888 derivatives Force_tac, force) combines rewriting and classical
  1889 reasoning (and whatever other tools) similarly to auto_tac, but is
  1890 aimed to solve the given subgoal completely.
  1891 
  1892 
  1893 *** General ***
  1894 
  1895 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1896 and `goalw': the theory is no longer needed as an explicit argument -
  1897 the current theory context is used; assumptions are no longer returned
  1898 at the ML-level unless one of them starts with ==> or !!; it is
  1899 recommended to convert to these new commands using isatool fixgoal
  1900 (backup your sources first!);
  1901 
  1902 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1903 the current theory context, and 'theory' to lookup stored theories;
  1904 
  1905 * new theory section 'locale' for declaring constants, assumptions and
  1906 definitions that have local scope;
  1907 
  1908 * new theory section 'nonterminals' for purely syntactic types;
  1909 
  1910 * new theory section 'setup' for generic ML setup functions
  1911 (e.g. package initialization);
  1912 
  1913 * the distribution now includes Isabelle icons: see
  1914 lib/logo/isabelle-{small,tiny}.xpm;
  1915 
  1916 * isatool install - install binaries with absolute references to
  1917 ISABELLE_HOME/bin;
  1918 
  1919 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1920 
  1921 * print mode 'emacs' reserved for Isamode;
  1922 
  1923 * support multiple print (ast) translations per constant name;
  1924 
  1925 * theorems involving oracles are now printed with a suffixed [!];
  1926 
  1927 
  1928 *** HOL ***
  1929 
  1930 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1931 
  1932 * HOL/inductive package reorganized and improved: now supports mutual
  1933 definitions such as
  1934 
  1935   inductive EVEN ODD
  1936     intrs
  1937       null "0 : EVEN"
  1938       oddI "n : EVEN ==> Suc n : ODD"
  1939       evenI "n : ODD ==> Suc n : EVEN"
  1940 
  1941 new theorem list "elims" contains an elimination rule for each of the
  1942 recursive sets; inductive definitions now handle disjunctive premises
  1943 correctly (also ZF);
  1944 
  1945 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1946 "mutual_induct" no longer exists - the induction rule is always
  1947 contained in "induct";
  1948 
  1949 
  1950 * HOL/datatype package re-implemented and greatly improved: now
  1951 supports mutually recursive datatypes such as
  1952 
  1953   datatype
  1954     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1955             | SUM ('a aexp) ('a aexp)
  1956             | DIFF ('a aexp) ('a aexp)
  1957             | NUM 'a
  1958   and
  1959     'a bexp = LESS ('a aexp) ('a aexp)
  1960             | AND ('a bexp) ('a bexp)
  1961             | OR ('a bexp) ('a bexp)
  1962 
  1963 as well as indirectly recursive datatypes such as
  1964 
  1965   datatype
  1966     ('a, 'b) term = Var 'a
  1967                   | App 'b ((('a, 'b) term) list)
  1968 
  1969 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1970 induction on mutually / indirectly recursive datatypes.
  1971 
  1972 Primrec equations are now stored in theory and can be accessed via
  1973 <function_name>.simps.
  1974 
  1975 INCOMPATIBILITIES:
  1976 
  1977   - Theories using datatypes must now have theory Datatype as an
  1978     ancestor.
  1979   - The specific <typename>.induct_tac no longer exists - use the
  1980     generic induct_tac instead.
  1981   - natE has been renamed to nat.exhaust - use exhaust_tac
  1982     instead of res_inst_tac ... natE. Note that the variable
  1983     names in nat.exhaust differ from the names in natE, this
  1984     may cause some "fragile" proofs to fail.
  1985   - The theorems split_<typename>_case and split_<typename>_case_asm
  1986     have been renamed to <typename>.split and <typename>.split_asm.
  1987   - Since default sorts of type variables are now handled correctly,
  1988     some datatype definitions may have to be annotated with explicit
  1989     sort constraints.
  1990   - Primrec definitions no longer require function name and type
  1991     of recursive argument.
  1992 
  1993 Consider using isatool fixdatatype to adapt your theories and proof
  1994 scripts to the new package (backup your sources first!).
  1995 
  1996 
  1997 * HOL/record package: considerably improved implementation; now
  1998 includes concrete syntax for record types, terms, updates; theorems
  1999 for surjective pairing and splitting !!-bound record variables; proof
  2000 support is as follows:
  2001 
  2002   1) standard conversions (selectors or updates applied to record
  2003 constructor terms) are part of the standard simpset;
  2004 
  2005   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2006 made part of standard simpset and claset via addIffs;
  2007 
  2008   3) a tactic for record field splitting (record_split_tac) is part of
  2009 the standard claset (addSWrapper);
  2010 
  2011 To get a better idea about these rules you may retrieve them via
  2012 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2013 the name of your record type.
  2014 
  2015 The split tactic 3) conceptually simplifies by the following rule:
  2016 
  2017   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2018 
  2019 Thus any record variable that is bound by meta-all will automatically
  2020 blow up into some record constructor term, consequently the
  2021 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2022 solve record problems automatically.
  2023 
  2024 
  2025 * reorganized the main HOL image: HOL/Integ and String loaded by
  2026 default; theory Main includes everything;
  2027 
  2028 * automatic simplification of integer sums and comparisons, using cancellation;
  2029 
  2030 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2031 
  2032 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2033 
  2034 * many new identities for unions, intersections, set difference, etc.;
  2035 
  2036 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2037 called split_if, split_split, split_sum_case and split_nat_case (to go
  2038 with add/delsplits);
  2039 
  2040 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2041 (?x::unit) = (); this is made part of the default simpset, which COULD
  2042 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2043 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2044 unit_abs_eta_conv is added in order to counter the effect of
  2045 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2046 %u.f();
  2047 
  2048 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2049 makes more sense);
  2050 
  2051 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2052   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2053   disjointness reasoning but breaking a few old proofs.
  2054 
  2055 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2056 to 'converse' from 'inverse' (for compatibility with ZF and some
  2057 literature);
  2058 
  2059 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2060 the well-founded relation;
  2061 
  2062 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2063     Compl A.  The "Compl" syntax remains available as input syntax for this
  2064     release ONLY.
  2065 
  2066 * HOL/Update: new theory of function updates:
  2067     f(a:=b) == %x. if x=a then b else f x
  2068 may also be iterated as in f(a:=b,c:=d,...);
  2069 
  2070 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2071 
  2072 * HOL/List:
  2073   - new function list_update written xs[i:=v] that updates the i-th
  2074     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2075   - new function `upt' written [i..j(] which generates the list
  2076     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2077     bound write [i..j], which is a shorthand for [i..j+1(].
  2078   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2079 
  2080 * HOL/Arith:
  2081   - removed 'pred' (predecessor) function;
  2082   - generalized some theorems about n-1;
  2083   - many new laws about "div" and "mod";
  2084   - new laws about greatest common divisors (see theory ex/Primes);
  2085 
  2086 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2087 instead of "inverse";
  2088 
  2089 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2090   of the multiset ordering;
  2091 
  2092 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2093   (not included by default);
  2094 
  2095 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2096 
  2097 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2098   programs, i.e. different program variables may have different types.
  2099 
  2100 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2101   [previously, this check worked only if the rewrite rule was unconditional]
  2102   Now rew can involve either definitions or equalities (either == or =).
  2103 
  2104 
  2105 *** ZF ***
  2106 
  2107 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2108   only the theorems proved on ZF.ML;
  2109 
  2110 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2111   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2112   disjointness reasoning but breaking a few old proofs.
  2113 
  2114 * ZF/Update: new theory of function updates
  2115     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2116   may also be iterated as in f(a:=b,c:=d,...);
  2117 
  2118 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2119 
  2120 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2121   [previously, this check worked only if the rewrite rule was unconditional]
  2122   Now rew can involve either definitions or equalities (either == or =).
  2123 
  2124 * case_tac provided for compatibility with HOL
  2125     (like the old excluded_middle_tac, but with subgoals swapped)
  2126 
  2127 
  2128 *** Internal programming interfaces ***
  2129 
  2130 * Pure: several new basic modules made available for general use, see
  2131 also src/Pure/README;
  2132 
  2133 * improved the theory data mechanism to support encapsulation (data
  2134 kind name replaced by private Object.kind, acting as authorization
  2135 key); new type-safe user interface via functor TheoryDataFun; generic
  2136 print_data function becomes basically useless;
  2137 
  2138 * removed global_names compatibility flag -- all theory declarations
  2139 are qualified by default;
  2140 
  2141 * module Pure/Syntax now offers quote / antiquote translation
  2142 functions (useful for Hoare logic etc. with implicit dependencies);
  2143 see HOL/ex/Antiquote for an example use;
  2144 
  2145 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2146 cterm -> thm;
  2147 
  2148 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2149 subgoal;
  2150 
  2151 * Display.print_goals function moved to Locale.print_goals;
  2152 
  2153 * standard print function for goals supports current_goals_markers
  2154 variable for marking begin of proof, end of proof, start of goal; the
  2155 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2156 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2157 for example;
  2158 
  2159 
  2160 
  2161 New in Isabelle98 (January 1998)
  2162 --------------------------------
  2163 
  2164 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2165 
  2166 * changed lexical syntax of terms / types: dots made part of long
  2167 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2168 
  2169 * simpset (and claset) reference variable replaced by functions
  2170 simpset / simpset_ref;
  2171 
  2172 * no longer supports theory aliases (via merge) and non-trivial
  2173 implicit merge of thms' signatures;
  2174 
  2175 * most internal names of constants changed due to qualified names;
  2176 
  2177 * changed Pure/Sequence interface (see Pure/seq.ML);
  2178 
  2179 
  2180 *** General Changes ***
  2181 
  2182 * hierachically structured name spaces (for consts, types, axms, thms
  2183 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2184 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2185 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2186 long_names for fully qualified output names; NOTE: ML programs
  2187 (special tactics, packages etc.) referring to internal names may have
  2188 to be adapted to cope with fully qualified names; in case of severe
  2189 backward campatibility problems try setting 'global_names' at compile
  2190 time to have enrything declared within a flat name space; one may also
  2191 fine tune name declarations in theories via the 'global' and 'local'
  2192 section;
  2193 
  2194 * reimplemented the implicit simpset and claset using the new anytype
  2195 data filed in signatures; references simpset:simpset ref etc. are
  2196 replaced by functions simpset:unit->simpset and
  2197 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2198 to patch your ML files accordingly;
  2199 
  2200 * HTML output now includes theory graph data for display with Java
  2201 applet or isatool browser; data generated automatically via isatool
  2202 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2203 
  2204 * defs may now be conditional; improved rewrite_goals_tac to handle
  2205 conditional equations;
  2206 
  2207 * defs now admits additional type arguments, using TYPE('a) syntax;
  2208 
  2209 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2210 creates a new theory node; implicit merge of thms' signatures is
  2211 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2212 transfer:theory->thm->thm in (rare) cases;
  2213 
  2214 * improved handling of draft signatures / theories; draft thms (and
  2215 ctyps, cterms) are automatically promoted to real ones;
  2216 
  2217 * slightly changed interfaces for oracles: admit many per theory, named
  2218 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2219 
  2220 * print_goals: optional output of const types (set show_consts and
  2221 show_types);
  2222 
  2223 * improved output of warnings (###) and errors (***);
  2224 
  2225 * subgoal_tac displays a warning if the new subgoal has type variables;
  2226 
  2227 * removed old README and Makefiles;
  2228 
  2229 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2230 
  2231 * removed obsolete init_pps and init_database;
  2232 
  2233 * deleted the obsolete tactical STATE, which was declared by
  2234     fun STATE tacfun st = tacfun st st;
  2235 
  2236 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2237 (which abbreviates $HOME);
  2238 
  2239 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2240 use isatool fixseq to adapt your ML programs (this works for fully
  2241 qualified references to the Sequence structure only!);
  2242 
  2243 * use_thy no longer requires writable current directory; it always
  2244 reloads .ML *and* .thy file, if either one is out of date;
  2245 
  2246 
  2247 *** Classical Reasoner ***
  2248 
  2249 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2250 tactics that use classical reasoning to simplify a subgoal without
  2251 splitting it into several subgoals;
  2252 
  2253 * Safe_tac: like safe_tac but uses the default claset;
  2254 
  2255 
  2256 *** Simplifier ***
  2257 
  2258 * added simplification meta rules:
  2259     (asm_)(full_)simplify: simpset -> thm -> thm;
  2260 
  2261 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2262 logics (again);
  2263 
  2264 * added prems argument to simplification procedures;
  2265 
  2266 * HOL, FOL, ZF: added infix function `addsplits':
  2267   instead of `<simpset> setloop (split_tac <thms>)'
  2268   you can simply write `<simpset> addsplits <thms>'
  2269 
  2270 
  2271 *** Syntax ***
  2272 
  2273 * TYPE('a) syntax for type reflection terms;
  2274 
  2275 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2276 
  2277 * pretty printer: changed order of mixfix annotation preference (again!);
  2278 
  2279 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2280 
  2281 
  2282 *** HOL ***
  2283 
  2284 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2285   with `addloop' of the simplifier to faciliate case splitting in premises.
  2286 
  2287 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2288 
  2289 * HOL/Auth: new protocol proofs including some for the Internet
  2290   protocol TLS;
  2291 
  2292 * HOL/Map: new theory of `maps' a la VDM;
  2293 
  2294 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2295 cancelling out common nat summands from =, <, <= (in)equalities, or
  2296 differences; simplification procedures nat_cancel_factor for
  2297 cancelling common factor from =, <, <= (in)equalities over natural
  2298 sums; nat_cancel contains both kinds of procedures, it is installed by
  2299 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2300 
  2301 * HOL/simplifier: terms of the form
  2302   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2303   are rewritten to
  2304   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2305   and those of the form
  2306   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2307   are rewritten to
  2308   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2309 
  2310 * HOL/datatype
  2311   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2312 
  2313   P(t_case f1 ... fn x) =
  2314      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2315         ...
  2316        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2317      )
  2318 
  2319   and a theorem `split_t_case_asm' of the form
  2320 
  2321   P(t_case f1 ... fn x) =
  2322     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2323         ...
  2324        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2325      )
  2326   which can be added to a simpset via `addsplits'. The existing theorems
  2327   expand_list_case and expand_option_case have been renamed to
  2328   split_list_case and split_option_case.
  2329 
  2330 * HOL/Arithmetic:
  2331   - `pred n' is automatically converted to `n-1'.
  2332     Users are strongly encouraged not to use `pred' any longer,
  2333     because it will disappear altogether at some point.
  2334   - Users are strongly encouraged to write "0 < n" rather than
  2335     "n ~= 0". Theorems and proof tools have been modified towards this
  2336     `standard'.
  2337 
  2338 * HOL/Lists:
  2339   the function "set_of_list" has been renamed "set" (and its theorems too);
  2340   the function "nth" now takes its arguments in the reverse order and
  2341   has acquired the infix notation "!" as in "xs!n".
  2342 
  2343 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2344 
  2345 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2346   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2347 
  2348 * HOL/record: extensible records with schematic structural subtyping
  2349 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2350 still lacks various theorems and concrete record syntax;
  2351 
  2352 
  2353 *** HOLCF ***
  2354 
  2355 * removed "axioms" and "generated by" sections;
  2356 
  2357 * replaced "ops" section by extended "consts" section, which is capable of
  2358   handling the continuous function space "->" directly;
  2359 
  2360 * domain package:
  2361   . proves theorems immediately and stores them in the theory,
  2362   . creates hierachical name space,
  2363   . now uses normal mixfix annotations (instead of cinfix...),
  2364   . minor changes to some names and values (for consistency),
  2365   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2366   . separator between mutual domain defs: changed "," to "and",
  2367   . improved handling of sort constraints;  now they have to
  2368     appear on the left-hand side of the equations only;
  2369 
  2370 * fixed LAM <x,y,zs>.b syntax;
  2371 
  2372 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2373 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2374 
  2375 
  2376 *** FOL and ZF ***
  2377 
  2378 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2379   with `addloop' of the simplifier to faciliate case splitting in premises.
  2380 
  2381 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2382 in HOL, they strip ALL and --> from proved theorems;
  2383 
  2384 
  2385 
  2386 New in Isabelle94-8 (May 1997)
  2387 ------------------------------
  2388 
  2389 *** General Changes ***
  2390 
  2391 * new utilities to build / run / maintain Isabelle etc. (in parts
  2392 still somewhat experimental); old Makefiles etc. still functional;
  2393 
  2394 * new 'Isabelle System Manual';
  2395 
  2396 * INSTALL text, together with ./configure and ./build scripts;
  2397 
  2398 * reimplemented type inference for greater efficiency, better error
  2399 messages and clean internal interface;
  2400 
  2401 * prlim command for dealing with lots of subgoals (an easier way of
  2402 setting goals_limit);
  2403 
  2404 
  2405 *** Syntax ***
  2406 
  2407 * supports alternative (named) syntax tables (parser and pretty
  2408 printer); internal interface is provided by add_modesyntax(_i);
  2409 
  2410 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2411 be used in conjunction with the Isabelle symbol font; uses the
  2412 "symbols" syntax table;
  2413 
  2414 * added token_translation interface (may translate name tokens in
  2415 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2416 the current print_mode); IMPORTANT: user print translation functions
  2417 are responsible for marking newly introduced bounds
  2418 (Syntax.mark_boundT);
  2419 
  2420 * token translations for modes "xterm" and "xterm_color" that display
  2421 names in bold, underline etc. or colors (which requires a color
  2422 version of xterm);
  2423 
  2424 * infixes may now be declared with names independent of their syntax;
  2425 
  2426 * added typed_print_translation (like print_translation, but may
  2427 access type of constant);
  2428 
  2429 
  2430 *** Classical Reasoner ***
  2431 
  2432 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2433 some limitations.  Blast_tac...
  2434   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2435   + ignores elimination rules that don't have the correct format
  2436         (the conclusion MUST be a formula variable)
  2437   + ignores types, which can make HOL proofs fail
  2438   + rules must not require higher-order unification, e.g. apply_type in ZF
  2439     [message "Function Var's argument not a bound variable" relates to this]
  2440   + its proof strategy is more general but can actually be slower
  2441 
  2442 * substitution with equality assumptions no longer permutes other
  2443 assumptions;
  2444 
  2445 * minor changes in semantics of addafter (now called addaltern); renamed
  2446 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2447 (and access functions for it);
  2448 
  2449 * improved combination of classical reasoner and simplifier:
  2450   + functions for handling clasimpsets
  2451   + improvement of addss: now the simplifier is called _after_ the
  2452     safe steps.
  2453   + safe variant of addss called addSss: uses safe simplifications
  2454     _during_ the safe steps. It is more complete as it allows multiple
  2455     instantiations of unknowns (e.g. with slow_tac).
  2456 
  2457 *** Simplifier ***
  2458 
  2459 * added interface for simplification procedures (functions that
  2460 produce *proven* rewrite rules on the fly, depending on current
  2461 redex);
  2462 
  2463 * ordering on terms as parameter (used for ordered rewriting);
  2464 
  2465 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2466 
  2467 * the solver is now split into a safe and an unsafe part.
  2468 This should be invisible for the normal user, except that the
  2469 functions setsolver and addsolver have been renamed to setSolver and
  2470 addSolver; added safe_asm_full_simp_tac;
  2471 
  2472 
  2473 *** HOL ***
  2474 
  2475 * a generic induction tactic `induct_tac' which works for all datatypes and
  2476 also for type `nat';
  2477 
  2478 * a generic case distinction tactic `exhaust_tac' which works for all
  2479 datatypes and also for type `nat';
  2480 
  2481 * each datatype comes with a function `size';
  2482 
  2483 * patterns in case expressions allow tuple patterns as arguments to
  2484 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2485 
  2486 * primrec now also works with type nat;
  2487 
  2488 * recdef: a new declaration form, allows general recursive functions to be
  2489 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2490 
  2491 * the constant for negation has been renamed from "not" to "Not" to
  2492 harmonize with FOL, ZF, LK, etc.;
  2493 
  2494 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2495 infinite lists;
  2496 
  2497 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2498 
  2499 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2500 problems in commutative rings, using axiomatic type classes for + and *;
  2501 
  2502 * more examples in HOL/MiniML and HOL/Auth;
  2503 
  2504 * more default rewrite rules for quantifiers, union/intersection;
  2505 
  2506 * a new constant `arbitrary == @x.False';
  2507 
  2508 * HOLCF/IOA replaces old HOL/IOA;
  2509 
  2510 * HOLCF changes: derived all rules and arities
  2511   + axiomatic type classes instead of classes
  2512   + typedef instead of faking type definitions
  2513   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2514   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2515   + eliminated the types void, one, tr
  2516   + use unit lift and bool lift (with translations) instead of one and tr
  2517   + eliminated blift from Lift3.thy (use Def instead of blift)
  2518   all eliminated rules are derived as theorems --> no visible changes ;
  2519 
  2520 
  2521 *** ZF ***
  2522 
  2523 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2524 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2525 as ZF_cs addSIs [equalityI];
  2526 
  2527 
  2528 
  2529 New in Isabelle94-7 (November 96)
  2530 ---------------------------------
  2531 
  2532 * allowing negative levels (as offsets) in prlev and choplev;
  2533 
  2534 * super-linear speedup for large simplifications;
  2535 
  2536 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2537 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2538 FAIL); can suppress it using the command Delsimps (ex_simps @
  2539 all_simps); De Morgan laws are also now included, by default;
  2540 
  2541 * improved printing of ==>  :  ~:
  2542 
  2543 * new object-logic "Sequents" adds linear logic, while replacing LK
  2544 and Modal (thanks to Sara Kalvala);
  2545 
  2546 * HOL/Auth: correctness proofs for authentication protocols;
  2547 
  2548 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2549 examples on HOL/Auth);
  2550 
  2551 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2552 the rewriter and classical reasoner simultaneously;
  2553 
  2554 * function uresult no longer returns theorems in "standard" format;
  2555 regain previous version by: val uresult = standard o uresult;
  2556 
  2557 
  2558 
  2559 New in Isabelle94-6
  2560 -------------------
  2561 
  2562 * oracles -- these establish an interface between Isabelle and trusted
  2563 external reasoners, which may deliver results as theorems;
  2564 
  2565 * proof objects (in particular record all uses of oracles);
  2566 
  2567 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2568 
  2569 * "constdefs" section in theory files;
  2570 
  2571 * "primrec" section (HOL) no longer requires names;
  2572 
  2573 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2574 
  2575 
  2576 
  2577 New in Isabelle94-5
  2578 -------------------
  2579 
  2580 * reduced space requirements;
  2581 
  2582 * automatic HTML generation from theories;
  2583 
  2584 * theory files no longer require "..." (quotes) around most types;
  2585 
  2586 * new examples, including two proofs of the Church-Rosser theorem;
  2587 
  2588 * non-curried (1994) version of HOL is no longer distributed;
  2589 
  2590 
  2591 
  2592 New in Isabelle94-4
  2593 -------------------
  2594 
  2595 * greatly reduced space requirements;
  2596 
  2597 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2598 
  2599 * searchable theorem database (see the section "Retrieving theorems" on
  2600 page 8 of the Reference Manual);
  2601 
  2602 * new examples, including Grabczewski's monumental case study of the
  2603 Axiom of Choice;
  2604 
  2605 * The previous version of HOL renamed to Old_HOL;
  2606 
  2607 * The new version of HOL (previously called CHOL) uses a curried syntax
  2608 for functions.  Application looks like f a b instead of f(a,b);
  2609 
  2610 * Mutually recursive inductive definitions finally work in HOL;
  2611 
  2612 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2613 translates to the operator "split";
  2614 
  2615 
  2616 
  2617 New in Isabelle94-3
  2618 -------------------
  2619 
  2620 * new infix operator, addss, allowing the classical reasoner to
  2621 perform simplification at each step of its search.  Example:
  2622         fast_tac (cs addss ss)
  2623 
  2624 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2625 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2626 look like (a,b) instead of <a,b>;
  2627 
  2628 * PLEASE NOTE: CHOL will eventually replace HOL!
  2629 
  2630 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2631 It translates to the operator "split".  A new theory of integers is available;
  2632 
  2633 * In ZF, integer numerals now denote two's-complement binary integers.
  2634 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2635 
  2636 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2637 of the Axiom of Choice;
  2638 
  2639 
  2640 
  2641 New in Isabelle94-2
  2642 -------------------
  2643 
  2644 * Significantly faster resolution;
  2645 
  2646 * the different sections in a .thy file can now be mixed and repeated
  2647 freely;
  2648 
  2649 * Database of theorems for FOL, HOL and ZF.  New
  2650 commands including qed, qed_goal and bind_thm store theorems in the database.
  2651 
  2652 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2653 a given theory (thms_of), or find out what theory a theorem was proved in
  2654 (theory_of_thm);
  2655 
  2656 * Bugs fixed in the inductive definition and datatype packages;
  2657 
  2658 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2659 and HOL_dup_cs obsolete;
  2660 
  2661 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2662 have been removed;
  2663 
  2664 * Simpler definition of function space in ZF;
  2665 
  2666 * new results about cardinal and ordinal arithmetic in ZF;
  2667 
  2668 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2669 types;
  2670 
  2671 
  2672 $Id$