NEWS
author schirmer
Mon Jan 26 10:34:02 2004 +0100 (2004-01-26)
changeset 14361 ad2f5da643b4
parent 14333 14f29eb097a3
child 14375 a545da363b23
permissions -rw-r--r--
* Support for raw latex output in control symbols: \<^raw...>
* Symbols may only start with one backslash: \<...>. \\<...> is no longer
accepted by the scanner.
- Adapted some Isar-theories to fit to this policy
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Pure: Greek letters (except small lambda, \<lambda>), as well as gothic
    10   (\<aa>...\<zz>\<AA>...\<ZZ>), caligraphic (\<A>...\<Z>), and euler
    11   (\<a>...\<z>), are now considered normal letters, and can therefore
    12   be used anywhere where an ASCII letter (a...zA...Z) has until
    13   now. COMPATIBILITY: This obviously changes the parsing of some
    14   terms, especially where a symbol has been used as a binder, say
    15   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
    16   as an identifier.  Fix it by inserting a space around former
    17   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
    18   existing theory and ML files.
    19 
    20 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
    21 
    22 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now 
    23   allowed in identifiers. Similar to greek letters \<^isub> is now considered 
    24   a normal (but invisible) letter. For multiple letter subscripts repeat 
    25   \<^isub> like this: x\<^isub>1\<^isub>2. 
    26 
    27 * Pure: There are now sub-/superscripts that can span more than one
    28   character. Text between \<^bsub> and \<^esub> is set in subscript in
    29   PG and LaTeX, text between \<^bsup> and \<^esup> in superscript. The
    30   new control characters are not identifier parts.
    31 
    32 * Pure: Control-symbols of the form \<^raw...> will literally print the
    33   content of ... to the latex file instead of \isacntrl... . The ... 
    34   accepts all printable characters excluding the end bracket >.
    35 
    36 * Pure: Symbols may only start with one backslash: \<...>. \\<...> is no 
    37   longer accepted by the scanner.
    38 
    39 * Pure: Using new Isar command "finalconsts" (or the ML functions
    40   Theory.add_finals or Theory.add_finals_i) it is now possible to
    41   declare constants "final", which prevents their being given a definition
    42   later.  It is useful for constants whose behaviour is fixed axiomatically
    43   rather than definitionally, such as the meta-logic connectives.
    44 
    45 *** Isar ***
    46 
    47 * Tactic emulation methods ?rule_tac, cut_tac, subgoal_tac and thin_tac:
    48   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    49     locales are no longer forced to write Isar proof scripts.
    50     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    51     emulations.
    52   - INCOMPATIBILITY: names of variables to be instantiated may no
    53     longer be enclosed in quotes.  Instead, precede variable name with `?'.
    54     This is consistent with the instantiation attribute "where".
    55 
    56 * Attributes "where" and "of":
    57   - Now take type variables of instantiated theorem into account when reading
    58     the instantiation string.  This fixes a bug that caused instantiated
    59     theorems to have too special types in some circumstances.
    60   - "where" permits explicit instantiations of type variables.
    61 
    62 * Calculation commands "moreover" and "also":
    63   Do not reset facts ("this") any more.
    64 
    65 * Locales:
    66   - Goal statements involving the context element "includes" no longer
    67     generate theorems with internal delta predicates (those ending on
    68     "_axioms") in the premise.
    69     Resolve particular premise with <locale>.intro to obtain old form.
    70   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
    71     specification and "includes" elements in goal statement.
    72   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
    73     [intro?] and [elim?] (respectively) by default.
    74 
    75 * HOL: Tactic emulation methods induct_tac and case_tac understand static
    76   (Isar) contexts.
    77 
    78 *** HOL ***
    79 
    80 * Records:
    81   - Record types are now by default printed with their type abbreviation
    82     instead of the list of all field types. This can be configured via
    83     the reference "print_record_type_abbr".
    84   - Simproc "record_upd_simproc" for simplification of multiple updates added 
    85     (not enabled by default).
    86   - Tactic "record_split_simp_tac" to split and simplify records added.
    87  
    88 * 'specification' command added, allowing for definition by
    89   specification.  There is also an 'ax_specification' command that
    90   introduces the new constants axiomatically.
    91 
    92 * SET-Protocol: formalization and verification of the SET protocol suite;
    93 
    94 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
    95  defintions, thanks to Sava Krsti\'{c} and John Matthews.
    96 
    97 New in Isabelle2003 (May 2003)
    98 --------------------------------
    99 
   100 *** General ***
   101 
   102 * Provers/simplifier:
   103 
   104   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   105     Assumptions are now subject to complete mutual simplification,
   106     not just from left to right. The simplifier now preserves
   107     the order of assumptions.
   108 
   109     Potential INCOMPATIBILITY:
   110 
   111     -- simp sometimes diverges where the old version did
   112        not, e.g. invoking simp on the goal
   113 
   114         [| P (f x); y = x; f x = f y |] ==> Q
   115 
   116        now gives rise to the infinite reduction sequence
   117 
   118         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   119 
   120        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   121        kind of problem.
   122 
   123     -- Tactics combining classical reasoner and simplification (such as auto)
   124        are also affected by this change, because many of them rely on
   125        simp. They may sometimes diverge as well or yield a different numbers
   126        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   127        in case of problems. Sometimes subsequent calls to the classical
   128        reasoner will fail because a preceeding call to the simplifier too
   129        eagerly simplified the goal, e.g. deleted redundant premises.
   130 
   131   - The simplifier trace now shows the names of the applied rewrite rules
   132 
   133   - You can limit the number of recursive invocations of the simplifier
   134     during conditional rewriting (where the simplifie tries to solve the
   135     conditions before applying the rewrite rule):
   136     ML "simp_depth_limit := n"
   137     where n is an integer. Thus you can force termination where previously
   138     the simplifier would diverge.
   139 
   140   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   141 
   142   - No longer aborts on failed congruence proof.  Instead, the
   143     congruence is ignored.
   144 
   145 * Pure: New generic framework for extracting programs from constructive
   146   proofs. See HOL/Extraction.thy for an example instantiation, as well
   147   as HOL/Extraction for some case studies.
   148 
   149 * Pure: The main goal of the proof state is no longer shown by default, only
   150 the subgoals. This behaviour is controlled by a new flag.
   151    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   152 (ML: Proof.show_main_goal).
   153 
   154 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   155 rules whose conclusion matches subgoal 1:
   156       PG menu: Isabelle/Isar -> Show me -> matching rules
   157 The rules are ordered by how closely they match the subgoal.
   158 In particular, rules that solve a subgoal outright are displayed first
   159 (or rather last, the way they are printed).
   160 (ML: ProofGeneral.print_intros())
   161 
   162 * Pure: New flag trace_unify_fail causes unification to print
   163 diagnostic information (PG: in trace buffer) when it fails. This is
   164 useful for figuring out why single step proofs like rule, erule or
   165 assumption failed.
   166 
   167 * Pure: Locale specifications now produce predicate definitions
   168 according to the body of text (covering assumptions modulo local
   169 definitions); predicate "loc_axioms" covers newly introduced text,
   170 while "loc" is cumulative wrt. all included locale expressions; the
   171 latter view is presented only on export into the global theory
   172 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   173 on the old view without predicates;
   174 
   175 * Pure: predefined locales "var" and "struct" are useful for sharing
   176 parameters (as in CASL, for example); just specify something like
   177 ``var x + var y + struct M'' as import;
   178 
   179 * Pure: improved thms_containing: proper indexing of facts instead of
   180 raw theorems; check validity of results wrt. current name space;
   181 include local facts of proof configuration (also covers active
   182 locales), cover fixed variables in index; may use "_" in term
   183 specification; an optional limit for the number of printed facts may
   184 be given (the default is 40);
   185 
   186 * Pure: disallow duplicate fact bindings within new-style theory files
   187 (batch-mode only);
   188 
   189 * Provers: improved induct method: assumptions introduced by case
   190 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   191 the goal statement); "foo" still refers to all facts collectively;
   192 
   193 * Provers: the function blast.overloaded has been removed: all constants
   194 are regarded as potentially overloaded, which improves robustness in exchange
   195 for slight decrease in efficiency;
   196 
   197 * Provers/linorder: New generic prover for transitivity reasoning over
   198 linear orders.  Note: this prover is not efficient!
   199 
   200 * Isar: preview of problems to finish 'show' now produce an error
   201 rather than just a warning (in interactive mode);
   202 
   203 
   204 *** HOL ***
   205 
   206 * arith(_tac)
   207 
   208  - Produces a counter example if it cannot prove a goal.
   209    Note that the counter example may be spurious if the goal is not a formula
   210    of quantifier-free linear arithmetic.
   211    In ProofGeneral the counter example appears in the trace buffer.
   212 
   213  - Knows about div k and mod k where k is a numeral of type nat or int.
   214 
   215  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   216    linear arithmetic fails. This takes account of quantifiers and divisibility.
   217    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   218 
   219 * simp's arithmetic capabilities have been enhanced a bit: it now
   220 takes ~= in premises into account (by performing a case split);
   221 
   222 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   223 are distributed over a sum of terms;
   224 
   225 * New tactic "trans_tac" and method "trans" instantiate
   226 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   227 "<=", "<" and "="). 
   228 
   229 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   230 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   231 
   232 * 'typedef' command has new option "open" to suppress the set
   233 definition;
   234 
   235 * functions Min and Max on finite sets have been introduced (theory
   236 Finite_Set);
   237 
   238 * attribute [symmetric] now works for relations as well; it turns
   239 (x,y) : R^-1 into (y,x) : R, and vice versa;
   240 
   241 * induct over a !!-quantified statement (say !!x1..xn):
   242   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   243 
   244 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   245 %x. None. Warning: empty_def now refers to the previously hidden definition
   246 of the empty set.
   247 
   248 * Algebra: formalization of classical algebra.  Intended as base for
   249 any algebraic development in Isabelle.  Currently covers group theory
   250 (up to Sylow's theorem) and ring theory (Universal Property of
   251 Univariate Polynomials).  Contributions welcome;
   252 
   253 * GroupTheory: deleted, since its material has been moved to Algebra;
   254 
   255 * Complex: new directory of the complex numbers with numeric constants, 
   256 nonstandard complex numbers, and some complex analysis, standard and 
   257 nonstandard (Jacques Fleuriot);
   258 
   259 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   260 
   261 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   262 Fleuriot);
   263 
   264 * Real/HahnBanach: updated and adapted to locales;
   265 
   266 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   267 Gray and Kramer);
   268 
   269 * UNITY: added the Meier-Sanders theory of progress sets;
   270 
   271 * MicroJava: bytecode verifier and lightweight bytecode verifier
   272 as abstract algorithms, instantiated to the JVM;
   273 
   274 * Bali: Java source language formalization. Type system, operational
   275 semantics, axiomatic semantics. Supported language features:
   276 classes, interfaces, objects,virtual methods, static methods,
   277 static/instance fields, arrays, access modifiers, definite
   278 assignment, exceptions.
   279 
   280 
   281 *** ZF ***
   282 
   283 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   284 universe, etc.);
   285 
   286 * Main ZF: virtually all theories converted to new-style format;
   287 
   288 
   289 *** ML ***
   290 
   291 * Pure: Tactic.prove provides sane interface for internal proofs;
   292 omits the infamous "standard" operation, so this is more appropriate
   293 than prove_goalw_cterm in many situations (e.g. in simprocs);
   294 
   295 * Pure: improved error reporting of simprocs;
   296 
   297 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   298 up simprocs;
   299 
   300 
   301 *** Document preparation ***
   302 
   303 * uses \par instead of \\ for line breaks in theory text. This may
   304 shift some page breaks in large documents. To get the old behaviour
   305 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   306 
   307 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   308 other packages
   309 
   310 * \<euro> now needs package babel/greek instead of marvosym (which
   311 broke \Rightarrow)
   312 
   313 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   314 textcomp package)
   315 
   316 
   317 New in Isabelle2002 (March 2002)
   318 --------------------------------
   319 
   320 *** Document preparation ***
   321 
   322 * greatly simplified document preparation setup, including more
   323 graceful interpretation of isatool usedir -i/-d/-D options, and more
   324 instructive isatool mkdir; users should basically be able to get
   325 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   326 users may run a separate document processing stage manually like this:
   327 "isatool usedir -D output HOL Test && isatool document Test/output";
   328 
   329 * theory dependency graph may now be incorporated into documents;
   330 isatool usedir -g true will produce session_graph.eps/.pdf for use
   331 with \includegraphics of LaTeX;
   332 
   333 * proper spacing of consecutive markup elements, especially text
   334 blocks after section headings;
   335 
   336 * support bold style (for single symbols only), input syntax is like
   337 this: "\<^bold>\<alpha>" or "\<^bold>A";
   338 
   339 * \<bullet> is now output as bold \cdot by default, which looks much
   340 better in printed text;
   341 
   342 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   343 note that these symbols are currently unavailable in Proof General /
   344 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   345 
   346 * isatool latex no longer depends on changed TEXINPUTS, instead
   347 isatool document copies the Isabelle style files to the target
   348 location;
   349 
   350 
   351 *** Isar ***
   352 
   353 * Pure/Provers: improved proof by cases and induction;
   354   - 'case' command admits impromptu naming of parameters (such as
   355     "case (Suc n)");
   356   - 'induct' method divinates rule instantiation from the inductive
   357     claim; no longer requires excessive ?P bindings for proper
   358     instantiation of cases;
   359   - 'induct' method properly enumerates all possibilities of set/type
   360     rules; as a consequence facts may be also passed through *type*
   361     rules without further ado;
   362   - 'induct' method now derives symbolic cases from the *rulified*
   363     rule (before it used to rulify cases stemming from the internal
   364     atomized version); this means that the context of a non-atomic
   365     statement becomes is included in the hypothesis, avoiding the
   366     slightly cumbersome show "PROP ?case" form;
   367   - 'induct' may now use elim-style induction rules without chaining
   368     facts, using ``missing'' premises from the goal state; this allows
   369     rules stemming from inductive sets to be applied in unstructured
   370     scripts, while still benefitting from proper handling of non-atomic
   371     statements; NB: major inductive premises need to be put first, all
   372     the rest of the goal is passed through the induction;
   373   - 'induct' proper support for mutual induction involving non-atomic
   374     rule statements (uses the new concept of simultaneous goals, see
   375     below);
   376   - append all possible rule selections, but only use the first
   377     success (no backtracking);
   378   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   379   - undeclared rule case names default to numbers 1, 2, 3, ...;
   380   - added 'print_induct_rules' (covered by help item in recent Proof
   381     General versions);
   382   - moved induct/cases attributes to Pure, methods to Provers;
   383   - generic method setup instantiated for FOL and HOL;
   384 
   385 * Pure: support multiple simultaneous goal statements, for example
   386 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   387 meta-level mechanism, this acts as if several individual goals had
   388 been stated separately; in particular common proof methods need to be
   389 repeated in order to cover all claims; note that a single elimination
   390 step is *not* sufficient to establish the two conjunctions, so this
   391 fails:
   392 
   393   assume "A & B" then have A and B ..   (*".." fails*)
   394 
   395 better use "obtain" in situations as above; alternative refer to
   396 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   397 
   398 * Pure: proper integration with ``locales''; unlike the original
   399 version by Florian Kammüller, Isar locales package high-level proof
   400 contexts rather than raw logical ones (e.g. we admit to include
   401 attributes everywhere); operations on locales include merge and
   402 rename; support for implicit arguments (``structures''); simultaneous
   403 type-inference over imports and text; see also HOL/ex/Locales.thy for
   404 some examples;
   405 
   406 * Pure: the following commands have been ``localized'', supporting a
   407 target locale specification "(in name)": 'lemma', 'theorem',
   408 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   409 stored both within the locale and at the theory level (exported and
   410 qualified by the locale name);
   411 
   412 * Pure: theory goals may now be specified in ``long'' form, with
   413 ad-hoc contexts consisting of arbitrary locale elements. for example
   414 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   415 definitions may be given, too); the result is a meta-level rule with
   416 the context elements being discharged in the obvious way;
   417 
   418 * Pure: new proof command 'using' allows to augment currently used
   419 facts after a goal statement ('using' is syntactically analogous to
   420 'apply', but acts on the goal's facts only); this allows chained facts
   421 to be separated into parts given before and after a claim, as in
   422 ``from a and b have C using d and e <proof>'';
   423 
   424 * Pure: renamed "antecedent" case to "rule_context";
   425 
   426 * Pure: new 'judgment' command records explicit information about the
   427 object-logic embedding (used by several tools internally); no longer
   428 use hard-wired "Trueprop";
   429 
   430 * Pure: added 'corollary' command;
   431 
   432 * Pure: fixed 'token_translation' command;
   433 
   434 * Pure: removed obsolete 'exported' attribute;
   435 
   436 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   437 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   438 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   439 
   440 * Pure: method 'atomize' presents local goal premises as object-level
   441 statements (atomic meta-level propositions); setup controlled via
   442 rewrite rules declarations of 'atomize' attribute; example
   443 application: 'induct' method with proper rule statements in improper
   444 proof *scripts*;
   445 
   446 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   447 now consider the syntactic context of assumptions, giving a better
   448 chance to get type-inference of the arguments right (this is
   449 especially important for locales);
   450 
   451 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   452 mode;
   453 
   454 * Pure/obtain: the formal conclusion "thesis", being marked as
   455 ``internal'', may no longer be reference directly in the text;
   456 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   457 situations;
   458 
   459 * Pure: generic 'sym' attribute which declares a rule both as pure
   460 'elim?' and for the 'symmetric' operation;
   461 
   462 * Pure: marginal comments ``--'' may now occur just anywhere in the
   463 text; the fixed correlation with particular command syntax has been
   464 discontinued;
   465 
   466 * Pure: new method 'rules' is particularly well-suited for proof
   467 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   468 but often produces more compact proof terms with less detours;
   469 
   470 * Pure/Provers/classical: simplified integration with pure rule
   471 attributes and methods; the classical "intro?/elim?/dest?"
   472 declarations coincide with the pure ones; the "rule" method no longer
   473 includes classically swapped intros; "intro" and "elim" methods no
   474 longer pick rules from the context; also got rid of ML declarations
   475 AddXIs/AddXEs/AddXDs; all of this has some potential for
   476 INCOMPATIBILITY;
   477 
   478 * Provers/classical: attribute 'swapped' produces classical inversions
   479 of introduction rules;
   480 
   481 * Provers/simplifier: 'simplified' attribute may refer to explicit
   482 rules instead of full simplifier context; 'iff' attribute handles
   483 conditional rules;
   484 
   485 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   486 
   487 * HOL: 'recdef' now fails on unfinished automated proofs, use
   488 "(permissive)" option to recover old behavior;
   489 
   490 * HOL: 'inductive' no longer features separate (collective) attributes
   491 for 'intros' (was found too confusing);
   492 
   493 * HOL: properly declared induction rules less_induct and
   494 wf_induct_rule;
   495 
   496 
   497 *** HOL ***
   498 
   499 * HOL: moved over to sane numeral syntax; the new policy is as
   500 follows:
   501 
   502   - 0 and 1 are polymorphic constants, which are defined on any
   503   numeric type (nat, int, real etc.);
   504 
   505   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   506   binary representation internally;
   507 
   508   - type nat has special constructor Suc, and generally prefers Suc 0
   509   over 1::nat and Suc (Suc 0) over 2::nat;
   510 
   511 This change may cause significant problems of INCOMPATIBILITY; here
   512 are some hints on converting existing sources:
   513 
   514   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   515   entities, so expressions involving "-" (unary or binary minus) need
   516   to be spaced properly;
   517 
   518   - existing occurrences of "1" may need to be constraint "1::nat" or
   519   even replaced by Suc 0; similar for old "2";
   520 
   521   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   522 
   523   - remove all special provisions on numerals in proofs;
   524 
   525 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   526 representation (depends on bin_arith_simps in the default context);
   527 
   528 * HOL: symbolic syntax for x^2 (numeral 2);
   529 
   530 * HOL: the class of all HOL types is now called "type" rather than
   531 "term"; INCOMPATIBILITY, need to adapt references to this type class
   532 in axclass/classes, instance/arities, and (usually rare) occurrences
   533 in typings (of consts etc.); internally the class is called
   534 "HOL.type", ML programs should refer to HOLogic.typeS;
   535 
   536 * HOL/record package improvements:
   537   - new derived operations "fields" to build a partial record section,
   538     "extend" to promote a fixed record to a record scheme, and
   539     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   540     declared as simp by default;
   541   - shared operations ("more", "fields", etc.) now need to be always
   542     qualified) --- potential INCOMPATIBILITY;
   543   - removed "make_scheme" operations (use "make" with "extend") --
   544     INCOMPATIBILITY;
   545   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   546   - provides cases/induct rules for use with corresponding Isar
   547     methods (for concrete records, record schemes, concrete more
   548     parts, and schematic more parts -- in that order);
   549   - internal definitions directly based on a light-weight abstract
   550     theory of product types over typedef rather than datatype;
   551 
   552 * HOL: generic code generator for generating executable ML code from
   553 specifications; specific support for HOL constructs such as inductive
   554 datatypes and sets, as well as recursive functions; can be invoked
   555 via 'generate_code' theory section;
   556 
   557 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   558 
   559 * HOL: consolidated and renamed several theories.  In particular:
   560 	Ord.thy has been absorbed into HOL.thy
   561 	String.thy has been absorbed into List.thy
   562  
   563 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   564 (beware of argument permutation!);
   565 
   566 * HOL: linorder_less_split superseded by linorder_cases;
   567 
   568 * HOL/List: "nodups" renamed to "distinct";
   569 
   570 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   571 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   572   - Ex_def has changed, now need to use some_eq_ex
   573 
   574 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   575 in this (rare) case use:
   576 
   577   delSWrapper "split_all_tac"
   578   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   579 
   580 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   581 MAY FAIL;
   582 
   583 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   584 Isabelle's type classes, ^ on functions and relations has too general
   585 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   586 necessary to attach explicit type constraints;
   587 
   588 * HOL/Relation: the prefix name of the infix "O" has been changed from
   589 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   590 renamed accordingly (eg "compI" -> "rel_compI").
   591 
   592 * HOL: syntax translations now work properly with numerals and records
   593 expressions;
   594 
   595 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   596 of "lam" -- INCOMPATIBILITY;
   597 
   598 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   599 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   600 renamed "Product_Type.unit";
   601 
   602 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   603 
   604 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   605 the "cases" method);
   606 
   607 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   608 Florian Kammüller);
   609 
   610 * HOL/IMP: updated and converted to new-style theory format; several
   611 parts turned into readable document, with proper Isar proof texts and
   612 some explanations (by Gerwin Klein);
   613 
   614 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   615 
   616 * HOL-Hyperreal is now a logic image;
   617 
   618 
   619 *** HOLCF ***
   620 
   621 * Isar: consts/constdefs supports mixfix syntax for continuous
   622 operations;
   623 
   624 * Isar: domain package adapted to new-style theory format, e.g. see
   625 HOLCF/ex/Dnat.thy;
   626 
   627 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   628 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   629 lift.induct_tac, always use UU instead of Undef;
   630 
   631 * HOLCF/IMP: updated and converted to new-style theory;
   632 
   633 
   634 *** ZF ***
   635 
   636 * Isar: proper integration of logic-specific tools and packages,
   637 including theory commands '(co)inductive', '(co)datatype',
   638 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   639 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   640 
   641 * theory Main no longer includes AC; for the Axiom of Choice, base
   642 your theory on Main_ZFC;
   643 
   644 * the integer library now covers quotients and remainders, with many
   645 laws relating division to addition, multiplication, etc.;
   646 
   647 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   648 typeless version of the formalism;
   649 
   650 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   651 format;
   652 
   653 * ZF/Induct: new directory for examples of inductive definitions,
   654 including theory Multiset for multiset orderings; converted to
   655 new-style theory format;
   656 
   657 * ZF: many new theorems about lists, ordinals, etc.;
   658 
   659 
   660 *** General ***
   661 
   662 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   663 variable proof controls level of detail: 0 = no proofs (only oracle
   664 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   665 also ref manual for further ML interfaces;
   666 
   667 * Pure/axclass: removed obsolete ML interface
   668 goal_subclass/goal_arity;
   669 
   670 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   671 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   672 separate tokens, so expressions involving minus need to be spaced
   673 properly;
   674 
   675 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   676 rather than "infixl" or "infixr";
   677 
   678 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   679 sort constraint specifications in type inference; e.g. "x::_::foo"
   680 ensures that the type of "x" is of sort "foo" (but not necessarily a
   681 type variable);
   682 
   683 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   684 control output of nested => (types); the default behavior is
   685 "type_brackets";
   686 
   687 * Pure/syntax: builtin parse translation for "_constify" turns valued
   688 tokens into AST constants;
   689 
   690 * Pure/syntax: prefer later declarations of translations and print
   691 translation functions; potential INCOMPATIBILITY: need to reverse
   692 multiple declarations for same syntax element constant;
   693 
   694 * Pure/show_hyps reset by default (in accordance to existing Isar
   695 practice);
   696 
   697 * Provers/classical: renamed addaltern to addafter, addSaltern to
   698 addSafter;
   699 
   700 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   701 as well;
   702 
   703 * system: tested support for MacOS X; should be able to get Isabelle +
   704 Proof General to work in a plain Terminal after installing Poly/ML
   705 (e.g. from the Isabelle distribution area) and GNU bash alone
   706 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   707 support requires further installations, e.g. from
   708 http://fink.sourceforge.net/);
   709 
   710 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   711 
   712 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   713 of 40 MB), cf. ML_OPTIONS;
   714 
   715 * system: Proof General keywords specification is now part of the
   716 Isabelle distribution (see etc/isar-keywords.el);
   717 
   718 * system: support for persistent Proof General sessions (refrain from
   719 outdating all loaded theories on startup); user may create writable
   720 logic images like this: ``isabelle -q HOL Test'';
   721 
   722 * system: smart selection of Isabelle process versus Isabelle
   723 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   724 run both "isabelle" and "Isabelle" even if file names are badly
   725 damaged (executable inspects the case of the first letter of its own
   726 name); added separate "isabelle-process" and "isabelle-interface";
   727 
   728 * system: refrain from any attempt at filtering input streams; no
   729 longer support ``8bit'' encoding of old isabelle font, instead proper
   730 iso-latin characters may now be used; the related isatools
   731 "symbolinput" and "nonascii" have disappeared as well;
   732 
   733 * system: removed old "xterm" interface (the print modes "xterm" and
   734 "xterm_color" are still available for direct use in a suitable
   735 terminal);
   736 
   737 
   738 
   739 New in Isabelle99-2 (February 2001)
   740 -----------------------------------
   741 
   742 *** Overview of INCOMPATIBILITIES ***
   743 
   744 * HOL: please note that theories in the Library and elsewhere often use the
   745 new-style (Isar) format; to refer to their theorems in an ML script you must
   746 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   747 
   748 * HOL: inductive package no longer splits induction rule aggressively,
   749 but only as far as specified by the introductions given; the old
   750 format may be recovered via ML function complete_split_rule or attribute
   751 'split_rule (complete)';
   752 
   753 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   754 gfp_Tarski to gfp_unfold;
   755 
   756 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   757 
   758 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   759 relation); infix "^^" has been renamed "``"; infix "``" has been
   760 renamed "`"; "univalent" has been renamed "single_valued";
   761 
   762 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   763 operation;
   764 
   765 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   766 
   767 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   768 
   769 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   770 consequence, it is no longer monotonic wrt. the local goal context
   771 (which is now passed through the inductive cases);
   772 
   773 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   774 \<gg> to \<ggreater>;
   775 
   776 
   777 *** Document preparation ***
   778 
   779 * \isabellestyle{NAME} selects version of Isabelle output (currently
   780 available: are "it" for near math-mode best-style output, "sl" for
   781 slanted text style, and "tt" for plain type-writer; if no
   782 \isabellestyle command is given, output is according to slanted
   783 type-writer);
   784 
   785 * support sub/super scripts (for single symbols only), input syntax is
   786 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   787 
   788 * some more standard symbols; see Appendix A of the system manual for
   789 the complete list of symbols defined in isabellesym.sty;
   790 
   791 * improved isabelle style files; more abstract symbol implementation
   792 (should now use \isamath{...} and \isatext{...} in custom symbol
   793 definitions);
   794 
   795 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   796 state; Note that presentation of goal states does not conform to
   797 actual human-readable proof documents.  Please do not include goal
   798 states into document output unless you really know what you are doing!
   799 
   800 * proper indentation of antiquoted output with proportional LaTeX
   801 fonts;
   802 
   803 * no_document ML operator temporarily disables LaTeX document
   804 generation;
   805 
   806 * isatool unsymbolize tunes sources for plain ASCII communication;
   807 
   808 
   809 *** Isar ***
   810 
   811 * Pure: Isar now suffers initial goal statements to contain unbound
   812 schematic variables (this does not conform to actual readable proof
   813 documents, due to unpredictable outcome and non-compositional proof
   814 checking); users who know what they are doing may use schematic goals
   815 for Prolog-style synthesis of proven results;
   816 
   817 * Pure: assumption method (an implicit finishing) now handles actual
   818 rules as well;
   819 
   820 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   821 initial goal, declare "that" only as Pure intro (only for single
   822 steps); the "that" rule assumption may now be involved in implicit
   823 finishing, thus ".." becomes a feasible for trivial obtains;
   824 
   825 * Pure: default proof step now includes 'intro_classes'; thus trivial
   826 instance proofs may be performed by "..";
   827 
   828 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   829 statements as well;
   830 
   831 * Pure: more robust selection of calculational rules;
   832 
   833 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   834 rule (as well as the assumption rule);
   835 
   836 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   837 lemmas, using the graph browser tool;
   838 
   839 * Pure: predict failure of "show" in interactive mode;
   840 
   841 * Pure: 'thms_containing' now takes actual terms as arguments;
   842 
   843 * HOL: improved method 'induct' --- now handles non-atomic goals
   844 (potential INCOMPATIBILITY); tuned error handling;
   845 
   846 * HOL: cases and induct rules now provide explicit hints about the
   847 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   848 any remaining facts are inserted into the goal verbatim;
   849 
   850 * HOL: local contexts (aka cases) may now contain term bindings as
   851 well; the 'cases' and 'induct' methods new provide a ?case binding for
   852 the result to be shown in each case;
   853 
   854 * HOL: added 'recdef_tc' command;
   855 
   856 * isatool convert assists in eliminating legacy ML scripts;
   857 
   858 
   859 *** HOL ***
   860 
   861 * HOL/Library: a collection of generic theories to be used together
   862 with main HOL; the theory loader path already includes this directory
   863 by default; the following existing theories have been moved here:
   864 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   865 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   866 
   867 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   868 modelling and verification task performed in Isabelle/HOL +
   869 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   870 
   871 * HOL/Algebra: special summation operator SUM no longer exists, it has
   872 been replaced by setsum; infix 'assoc' now has priority 50 (like
   873 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   874 'domain', this makes the theory consistent with mathematical
   875 literature;
   876 
   877 * HOL basics: added overloaded operations "inverse" and "divide"
   878 (infix "/"), syntax for generic "abs" operation, generic summation
   879 operator \<Sum>;
   880 
   881 * HOL/typedef: simplified package, provide more useful rules (see also
   882 HOL/subset.thy);
   883 
   884 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   885 now expressed as a proper nested rule (old-style tactic scripts may
   886 require atomize_strip_tac to cope with non-atomic premises);
   887 
   888 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   889 to "split_conv" (old name still available for compatibility);
   890 
   891 * HOL: improved concrete syntax for strings (e.g. allows translation
   892 rules with string literals);
   893 
   894 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   895  and Fleuriot's mechanization of analysis, including the transcendental
   896  functions for the reals;
   897 
   898 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   899 
   900 
   901 *** CTT ***
   902 
   903 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   904 "lam" is displayed as TWO lambda-symbols
   905 
   906 * CTT: theory Main now available, containing everything (that is, Bool
   907 and Arith);
   908 
   909 
   910 *** General ***
   911 
   912 * Pure: the Simplifier has been implemented properly as a derived rule
   913 outside of the actual kernel (at last!); the overall performance
   914 penalty in practical applications is about 50%, while reliability of
   915 the Isabelle inference kernel has been greatly improved;
   916 
   917 * print modes "brackets" and "no_brackets" control output of nested =>
   918 (types) and ==> (props); the default behaviour is "brackets";
   919 
   920 * Provers: fast_tac (and friends) now handle actual object-logic rules
   921 as assumptions as well;
   922 
   923 * system: support Poly/ML 4.0;
   924 
   925 * system: isatool install handles KDE version 1 or 2;
   926 
   927 
   928 
   929 New in Isabelle99-1 (October 2000)
   930 ----------------------------------
   931 
   932 *** Overview of INCOMPATIBILITIES ***
   933 
   934 * HOL: simplification of natural numbers is much changed; to partly
   935 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   936 issue the following ML commands:
   937 
   938   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   939   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   940 
   941 * HOL: simplification no longer dives into case-expressions; this is
   942 controlled by "t.weak_case_cong" for each datatype t;
   943 
   944 * HOL: nat_less_induct renamed to less_induct;
   945 
   946 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   947 fixsome to patch .thy and .ML sources automatically;
   948 
   949   select_equality  -> some_equality
   950   select_eq_Ex     -> some_eq_ex
   951   selectI2EX       -> someI2_ex
   952   selectI2         -> someI2
   953   selectI          -> someI
   954   select1_equality -> some1_equality
   955   Eps_sym_eq       -> some_sym_eq_trivial
   956   Eps_eq           -> some_eq_trivial
   957 
   958 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   959 
   960 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   961 instead);
   962 
   963 * HOL: the recursion equations generated by 'recdef' are now called
   964 f.simps instead of f.rules;
   965 
   966 * HOL: qed_spec_mp now also handles bounded ALL as well;
   967 
   968 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   969 sometimes be needed;
   970 
   971 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   972 
   973 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   974 
   975 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   976 product is now "<*>" instead of "Times"; the lexicographic product is
   977 now "<*lex*>" instead of "**";
   978 
   979 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   980 of main HOL, but was unused); better use HOL's datatype package;
   981 
   982 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   983 the old syntax may be recovered as follows:
   984 
   985   syntax (symbols)
   986     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   987       (infixl "\\<oplus>" 100)
   988 
   989 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   990 
   991 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   992 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   993 internally;
   994 
   995 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   996 changed from A/r to A//r;
   997 
   998 * ZF: new treatment of arithmetic (nat & int) may break some old
   999 proofs;
  1000 
  1001 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1002 rulify -> rule_format, elimify -> elim_format, ...);
  1003 
  1004 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1005 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1006 should have to change intro!! to intro? only); replaced "delrule" by
  1007 "rule del";
  1008 
  1009 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1010 
  1011 * Provers: strengthened force_tac by using new first_best_tac;
  1012 
  1013 * LaTeX document preparation: several changes of isabelle.sty (see
  1014 lib/texinputs);
  1015 
  1016 
  1017 *** Document preparation ***
  1018 
  1019 * formal comments (text blocks etc.) in new-style theories may now
  1020 contain antiquotations of thm/prop/term/typ/text to be presented
  1021 according to latex print mode; concrete syntax is like this:
  1022 @{term[show_types] "f(x) = a + x"};
  1023 
  1024 * isatool mkdir provides easy setup of Isabelle session directories,
  1025 including proper document sources;
  1026 
  1027 * generated LaTeX sources are now deleted after successful run
  1028 (isatool document -c); may retain a copy somewhere else via -D option
  1029 of isatool usedir;
  1030 
  1031 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1032 style files, achieving self-contained LaTeX sources and simplifying
  1033 LaTeX debugging;
  1034 
  1035 * old-style theories now produce (crude) LaTeX output as well;
  1036 
  1037 * browser info session directories are now self-contained (may be put
  1038 on WWW server seperately); improved graphs of nested sessions; removed
  1039 graph for 'all sessions';
  1040 
  1041 * several improvements in isabelle style files; \isabellestyle{it}
  1042 produces fake math mode output; \isamarkupheader is now \section by
  1043 default; see lib/texinputs/isabelle.sty etc.;
  1044 
  1045 
  1046 *** Isar ***
  1047 
  1048 * Isar/Pure: local results and corresponding term bindings are now
  1049 subject to Hindley-Milner polymorphism (similar to ML); this
  1050 accommodates incremental type-inference very nicely;
  1051 
  1052 * Isar/Pure: new derived language element 'obtain' supports
  1053 generalized existence reasoning;
  1054 
  1055 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1056 support accumulation of results, without applying any rules yet;
  1057 useful to collect intermediate results without explicit name
  1058 references, and for use with transitivity rules with more than 2
  1059 premises;
  1060 
  1061 * Isar/Pure: scalable support for case-analysis type proofs: new
  1062 'case' language element refers to local contexts symbolically, as
  1063 produced by certain proof methods; internally, case names are attached
  1064 to theorems as "tags";
  1065 
  1066 * Isar/Pure: theory command 'hide' removes declarations from
  1067 class/type/const name spaces;
  1068 
  1069 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1070 indicate potential overloading;
  1071 
  1072 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1073 
  1074 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1075 "{a,b,c}" instead of {a,b,c};
  1076 
  1077 * Isar/Pure now provides its own version of intro/elim/dest
  1078 attributes; useful for building new logics, but beware of confusion
  1079 with the version in Provers/classical;
  1080 
  1081 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1082 case name 'antecedent';
  1083 
  1084 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1085 to the current context is now done automatically);
  1086 
  1087 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1088 for definining proof methods in ML;
  1089 
  1090 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1091 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1092 most cases, one should have to change intro!! to intro? only);
  1093 replaced "delrule" by "rule del";
  1094 
  1095 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1096 'symmetric' attribute (the latter supercedes [RS sym]);
  1097 
  1098 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1099 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1100 well (including splits);
  1101 
  1102 * Isar/Provers: Simplifier and Classical methods now support all kind
  1103 of modifiers used in the past, including 'cong', 'iff', etc.
  1104 
  1105 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1106 of Simplifier and Classical reasoner);
  1107 
  1108 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1109 now support named cases; major packages (inductive, datatype, primrec,
  1110 recdef) support case names and properly name parameters;
  1111 
  1112 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1113 monotonicity conditions are extracted to be proven at end of
  1114 calculations;
  1115 
  1116 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1117 method anyway;
  1118 
  1119 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1120 split_if split_if_asm; datatype package provides theorems foo.splits =
  1121 foo.split foo.split_asm for each datatype;
  1122 
  1123 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1124 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1125 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1126 use "(cases (simplified))" method in proper proof texts);
  1127 
  1128 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1129 
  1130 * Isar: names of theorems etc. may be natural numbers as well;
  1131 
  1132 * Isar: 'pr' command: optional arguments for goals_limit and
  1133 ProofContext.prems_limit; no longer prints theory contexts, but only
  1134 proof states;
  1135 
  1136 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1137 additional print modes to be specified; e.g. "pr(latex)" will print
  1138 proof state according to the Isabelle LaTeX style;
  1139 
  1140 * Isar: improved support for emulating tactic scripts, including proof
  1141 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1142 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1143 (for HOL datatypes);
  1144 
  1145 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1146 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1147 'proof method scripts' have to be in depth-first order;
  1148 
  1149 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1150 
  1151 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1152 should instead use individual commands for printing items
  1153 (print_commands, print_methods etc.);
  1154 
  1155 * Isar: added 'nothing' --- the empty list of theorems;
  1156 
  1157 
  1158 *** HOL ***
  1159 
  1160 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1161 corresponding virtual machine and a specification of its bytecode
  1162 verifier and a lightweight bytecode verifier, including proofs of
  1163 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1164 Cornelia Pusch (see also the homepage of project Bali at
  1165 http://isabelle.in.tum.de/Bali/);
  1166 
  1167 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1168 Clemens Ballarin;
  1169 
  1170 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1171 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1172 Rasmussen;
  1173 
  1174 * HOL/Lattice: fundamental concepts of lattice theory and order
  1175 structures, including duals, properties of bounds versus algebraic
  1176 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1177 Theorem for complete lattices etc.; may also serve as a demonstration
  1178 for abstract algebraic reasoning using axiomatic type classes, and
  1179 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1180 
  1181 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1182 von Oheimb;
  1183 
  1184 * HOL/IMPP: extension of IMP with local variables and mutually
  1185 recursive procedures, by David von Oheimb;
  1186 
  1187 * HOL/Lambda: converted into new-style theory and document;
  1188 
  1189 * HOL/ex/Multiquote: example of multiple nested quotations and
  1190 anti-quotations -- basically a generalized version of de-Bruijn
  1191 representation; very useful in avoiding lifting of operations;
  1192 
  1193 * HOL/record: added general record equality rule to simpset; fixed
  1194 select-update simplification procedure to handle extended records as
  1195 well; admit "r" as field name;
  1196 
  1197 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1198 other numeric types and also as the identity of groups, rings, etc.;
  1199 
  1200 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1201 Types nat and int belong to this axclass;
  1202 
  1203 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1204    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1205    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1206   two terms #m*u and #n*u are replaced by #(m+n)*u
  1207     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1208   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1209     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1210 
  1211 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1212 powerful prover for predicate logic but knows nothing of clasets; see
  1213 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1214 
  1215 * HOL: new version of "case_tac" subsumes both boolean case split and
  1216 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1217 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1218 
  1219 * HOL: simplification no longer dives into case-expressions: only the
  1220 selector expression is simplified, but not the remaining arms; to
  1221 enable full simplification of case-expressions for datatype t, you may
  1222 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1223 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1224 
  1225 * HOL/recdef: the recursion equations generated by 'recdef' for
  1226 function 'f' are now called f.simps instead of f.rules; if all
  1227 termination conditions are proved automatically, these simplification
  1228 rules are added to the simpset, as in primrec; rules may be named
  1229 individually as well, resulting in a separate list of theorems for
  1230 each equation;
  1231 
  1232 * HOL/While is a new theory that provides a while-combinator. It
  1233 permits the definition of tail-recursive functions without the
  1234 provision of a termination measure. The latter is necessary once the
  1235 invariant proof rule for while is applied.
  1236 
  1237 * HOL: new (overloaded) notation for the set of elements below/above
  1238 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1239 
  1240 * HOL: theorems impI, allI, ballI bound as "strip";
  1241 
  1242 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1243 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1244 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1245 
  1246 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1247 
  1248 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1249 main HOL, but was unused);
  1250 
  1251 * HOL: fewer consts declared as global (e.g. have to refer to
  1252 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1253 
  1254 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1255 in case of overlap with user translations (e.g. judgements over
  1256 tuples); (note that the underlying logical represenation is still
  1257 bogus);
  1258 
  1259 
  1260 *** ZF ***
  1261 
  1262 * ZF: simplification automatically cancels common terms in arithmetic
  1263 expressions over nat and int;
  1264 
  1265 * ZF: new treatment of nat to minimize type-checking: all operators
  1266 coerce their operands to a natural number using the function natify,
  1267 making the algebraic laws unconditional;
  1268 
  1269 * ZF: as above, for int: operators coerce their operands to an integer
  1270 using the function intify;
  1271 
  1272 * ZF: the integer library now contains many of the usual laws for the
  1273 orderings, including $<=, and monotonicity laws for $+ and $*;
  1274 
  1275 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1276 simplification;
  1277 
  1278 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1279 to the simplifier and classical reasoner simultaneously;
  1280 
  1281 
  1282 *** General ***
  1283 
  1284 * Provers: blast_tac now handles actual object-logic rules as
  1285 assumptions; note that auto_tac uses blast_tac internally as well;
  1286 
  1287 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1288 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1289 
  1290 * Provers: delrules now handles destruct rules as well (no longer need
  1291 explicit make_elim);
  1292 
  1293 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1294   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1295 use instead the strong form,
  1296   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1297 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1298 from destruct-rules;
  1299 
  1300 * Provers: Simplifier.easy_setup provides a fast path to basic
  1301 Simplifier setup for new object-logics;
  1302 
  1303 * Pure: AST translation rules no longer require constant head on LHS;
  1304 
  1305 * Pure: improved name spaces: ambiguous output is qualified; support
  1306 for hiding of names;
  1307 
  1308 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1309 XSYMBOL_HOME; no longer need to do manual configuration in most
  1310 situations;
  1311 
  1312 * system: compression of ML heaps images may now be controlled via -c
  1313 option of isabelle and isatool usedir (currently only observed by
  1314 Poly/ML);
  1315 
  1316 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1317 useful for remote X11);
  1318 
  1319 * system: provide TAGS file for Isabelle sources;
  1320 
  1321 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1322 order;
  1323 
  1324 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1325 timing flag supersedes proof_timing and Toplevel.trace;
  1326 
  1327 * ML: new combinators |>> and |>>> for incremental transformations
  1328 with secondary results (e.g. certain theory extensions):
  1329 
  1330 * ML: PureThy.add_defs gets additional argument to indicate potential
  1331 overloading (usually false);
  1332 
  1333 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1334 results;
  1335 
  1336 
  1337 
  1338 New in Isabelle99 (October 1999)
  1339 --------------------------------
  1340 
  1341 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1342 
  1343 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1344 are no longer simplified.  (This allows the simplifier to unfold recursive
  1345 functional programs.)  To restore the old behaviour, declare
  1346 
  1347     Delcongs [if_weak_cong];
  1348 
  1349 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1350 complement;
  1351 
  1352 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1353 
  1354 * HOL/datatype: mutual_induct_tac no longer exists --
  1355   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1356 
  1357 * HOL/typedef: fixed type inference for representing set; type
  1358 arguments now have to occur explicitly on the rhs as type constraints;
  1359 
  1360 * ZF: The con_defs part of an inductive definition may no longer refer
  1361 to constants declared in the same theory;
  1362 
  1363 * HOL, ZF: the function mk_cases, generated by the inductive
  1364 definition package, has lost an argument.  To simplify its result, it
  1365 uses the default simpset instead of a supplied list of theorems.
  1366 
  1367 * HOL/List: the constructors of type list are now Nil and Cons;
  1368 
  1369 * Simplifier: the type of the infix ML functions
  1370         setSSolver addSSolver setSolver addSolver
  1371 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1372 for packaging solvers. A solver is created via
  1373         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1374 where the string argument is only a comment.
  1375 
  1376 
  1377 *** Proof tools ***
  1378 
  1379 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1380 decision procedure for linear arithmetic. Currently it is used for
  1381 types `nat', `int', and `real' in HOL (see below); it can, should and
  1382 will be instantiated for other types and logics as well.
  1383 
  1384 * The simplifier now accepts rewrite rules with flexible heads, eg
  1385      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1386   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1387   matching.
  1388 
  1389 
  1390 *** General ***
  1391 
  1392 * New Isabelle/Isar subsystem provides an alternative to traditional
  1393 tactical theorem proving; together with the ProofGeneral/isar user
  1394 interface it offers an interactive environment for developing human
  1395 readable proof documents (Isar == Intelligible semi-automated
  1396 reasoning); for further information see isatool doc isar-ref,
  1397 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1398 
  1399 * improved and simplified presentation of theories: better HTML markup
  1400 (including colors), graph views in several sizes; isatool usedir now
  1401 provides a proper interface for user theories (via -P option); actual
  1402 document preparation based on (PDF)LaTeX is available as well (for
  1403 new-style theories only); see isatool doc system for more information;
  1404 
  1405 * native support for Proof General, both for classic Isabelle and
  1406 Isabelle/Isar;
  1407 
  1408 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1409 using the graph browser tool;
  1410 
  1411 * Isabelle manuals now also available as PDF;
  1412 
  1413 * theory loader rewritten from scratch (may not be fully
  1414 bug-compatible); old loadpath variable has been replaced by show_path,
  1415 add_path, del_path, reset_path functions; new operations such as
  1416 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1417 isatool doc ref);
  1418 
  1419 * improved isatool install: option -k creates KDE application icon,
  1420 option -p DIR installs standalone binaries;
  1421 
  1422 * added ML_PLATFORM setting (useful for cross-platform installations);
  1423 more robust handling of platform specific ML images for SML/NJ;
  1424 
  1425 * the settings environment is now statically scoped, i.e. it is never
  1426 created again in sub-processes invoked from isabelle, isatool, or
  1427 Isabelle;
  1428 
  1429 * path element specification '~~' refers to '$ISABELLE_HOME';
  1430 
  1431 * in locales, the "assumes" and "defines" parts may be omitted if
  1432 empty;
  1433 
  1434 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1435 long arrows);
  1436 
  1437 * new print_mode "HTML";
  1438 
  1439 * new flag show_tags controls display of tags of theorems (which are
  1440 basically just comments that may be attached by some tools);
  1441 
  1442 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1443 mode and goal output format:
  1444 
  1445 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1446 244c244
  1447 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1448 ---
  1449 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1450 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1451 181c181
  1452 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1453 ---
  1454 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1455 
  1456 * function bind_thms stores lists of theorems (cf. bind_thm);
  1457 
  1458 * new shorthand tactics ftac, eatac, datac, fatac;
  1459 
  1460 * qed (and friends) now accept "" as result name; in that case the
  1461 theorem is not stored, but proper checks and presentation of the
  1462 result still apply;
  1463 
  1464 * theorem database now also indexes constants "Trueprop", "all",
  1465 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1466 
  1467 
  1468 *** HOL ***
  1469 
  1470 ** HOL arithmetic **
  1471 
  1472 * There are now decision procedures for linear arithmetic over nat and
  1473 int:
  1474 
  1475 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1476 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1477 are treated as atomic; subformulae not involving type `nat' or `int'
  1478 are ignored; quantified subformulae are ignored unless they are
  1479 positive universal or negative existential. The tactic has to be
  1480 invoked by hand and can be a little bit slow. In particular, the
  1481 running time is exponential in the number of occurrences of `min' and
  1482 `max', and `-' on `nat'.
  1483 
  1484 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1485 (negated) (in)equalities among the premises and the conclusion into
  1486 account (i.e. no compound formulae) and does not know about `min' and
  1487 `max', and `-' on `nat'. It is fast and is used automatically by the
  1488 simplifier.
  1489 
  1490 NB: At the moment, these decision procedures do not cope with mixed
  1491 nat/int formulae where the two parts interact, such as `m < n ==>
  1492 int(m) < int(n)'.
  1493 
  1494 * HOL/Numeral provides a generic theory of numerals (encoded
  1495 efficiently as bit strings); setup for types nat/int/real is in place;
  1496 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1497 int, existing theories and proof scripts may require a few additional
  1498 type constraints;
  1499 
  1500 * integer division and remainder can now be performed on constant
  1501 arguments;
  1502 
  1503 * many properties of integer multiplication, division and remainder
  1504 are now available;
  1505 
  1506 * An interface to the Stanford Validity Checker (SVC) is available through the
  1507 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1508 are proved automatically.  SVC must be installed separately, and its results
  1509 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1510 invocation of the underlying oracle).  For SVC see
  1511   http://verify.stanford.edu/SVC
  1512 
  1513 * IsaMakefile: the HOL-Real target now builds an actual image;
  1514 
  1515 
  1516 ** HOL misc **
  1517 
  1518 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1519 (in Isabelle/Isar) -- by Gertrud Bauer;
  1520 
  1521 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1522 analysis for assembly languages with subtypes;
  1523 
  1524 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1525 -- avoids syntactic ambiguities and treats state, transition, and
  1526 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1527 changed syntax and (many) tactics;
  1528 
  1529 * HOL/inductive: Now also handles more general introduction rules such
  1530   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1531   theorems are now maintained within the theory (maintained via the
  1532   "mono" attribute);
  1533 
  1534 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1535   (using function types) such as
  1536 
  1537   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1538 
  1539 * HOL/record: record_simproc (part of the default simpset) takes care
  1540 of selectors applied to updated records; record_split_tac is no longer
  1541 part of the default claset; update_defs may now be removed from the
  1542 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1543 
  1544   claset_ref () := claset() addSWrapper record_split_wrapper;
  1545   Delsimprocs [record_simproc]
  1546 
  1547 * HOL/typedef: fixed type inference for representing set; type
  1548 arguments now have to occur explicitly on the rhs as type constraints;
  1549 
  1550 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1551 names rather than an ML expression;
  1552 
  1553 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1554 supplied later.  Program schemes can be defined, such as
  1555     "While B C s = (if B s then While B C (C s) else s)"
  1556 where the well-founded relation can be chosen after B and C have been given.
  1557 
  1558 * HOL/List: the constructors of type list are now Nil and Cons;
  1559 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1560 course, ML tools referring to List.list.op # etc. have to be adapted;
  1561 
  1562 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1563 disabled by default; run isabelle with option -m HOL to get back to
  1564 the original Gordon/HOL-style output;
  1565 
  1566 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1567 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1568 
  1569 * HOL basic syntax simplified (more orthogonal): all variants of
  1570 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1571 Eps operator is provided as well: "SOME x. P[x]";
  1572 
  1573 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1574 
  1575 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1576 thus available for user theories;
  1577 
  1578 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1579 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1580 time;
  1581 
  1582 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1583 several times and then mp;
  1584 
  1585 
  1586 *** LK ***
  1587 
  1588 * the notation <<...>> is now available as a notation for sequences of
  1589 formulas;
  1590 
  1591 * the simplifier is now installed
  1592 
  1593 * the axiom system has been generalized (thanks to Soren Heilmann)
  1594 
  1595 * the classical reasoner now has a default rule database
  1596 
  1597 
  1598 *** ZF ***
  1599 
  1600 * new primrec section allows primitive recursive functions to be given
  1601 directly (as in HOL) over datatypes and the natural numbers;
  1602 
  1603 * new tactics induct_tac and exhaust_tac for induction (or case
  1604 analysis) over datatypes and the natural numbers;
  1605 
  1606 * the datatype declaration of type T now defines the recursor T_rec;
  1607 
  1608 * simplification automatically does freeness reasoning for datatype
  1609 constructors;
  1610 
  1611 * automatic type-inference, with AddTCs command to insert new
  1612 type-checking rules;
  1613 
  1614 * datatype introduction rules are now added as Safe Introduction rules
  1615 to the claset;
  1616 
  1617 * the syntax "if P then x else y" is now available in addition to
  1618 if(P,x,y);
  1619 
  1620 
  1621 *** Internal programming interfaces ***
  1622 
  1623 * tuned simplifier trace output; new flag debug_simp;
  1624 
  1625 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1626 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1627 
  1628 * AxClass.axclass_tac lost the theory argument;
  1629 
  1630 * tuned current_goals_markers semantics: begin / end goal avoids
  1631 printing empty lines;
  1632 
  1633 * removed prs and prs_fn hook, which was broken because it did not
  1634 include \n in its semantics, forcing writeln to add one
  1635 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1636 string -> unit if you really want to output text without newline;
  1637 
  1638 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1639 plain output, interface builders may have to enable 'isabelle_font'
  1640 mode to get Isabelle font glyphs as before;
  1641 
  1642 * refined token_translation interface; INCOMPATIBILITY: output length
  1643 now of type real instead of int;
  1644 
  1645 * theory loader actions may be traced via new ThyInfo.add_hook
  1646 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1647 your own database of information attached to *whole* theories -- as
  1648 opposed to intra-theory data slots offered via TheoryDataFun;
  1649 
  1650 * proper handling of dangling sort hypotheses (at last!);
  1651 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1652 extra sort hypotheses that can be witnessed from the type signature;
  1653 the force_strip_shyps flag is gone, any remaining shyps are simply
  1654 left in the theorem (with a warning issued by strip_shyps_warning);
  1655 
  1656 
  1657 
  1658 New in Isabelle98-1 (October 1998)
  1659 ----------------------------------
  1660 
  1661 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1662 
  1663 * several changes of automated proof tools;
  1664 
  1665 * HOL: major changes to the inductive and datatype packages, including
  1666 some minor incompatibilities of theory syntax;
  1667 
  1668 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1669 called `inj_on';
  1670 
  1671 * HOL: removed duplicate thms in Arith:
  1672   less_imp_add_less  should be replaced by  trans_less_add1
  1673   le_imp_add_le      should be replaced by  trans_le_add1
  1674 
  1675 * HOL: unary minus is now overloaded (new type constraints may be
  1676 required);
  1677 
  1678 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1679 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1680 now taken as an integer constant.
  1681 
  1682 * Pure: ML function 'theory_of' renamed to 'theory';
  1683 
  1684 
  1685 *** Proof tools ***
  1686 
  1687 * Simplifier:
  1688   1. Asm_full_simp_tac is now more aggressive.
  1689      1. It will sometimes reorient premises if that increases their power to
  1690         simplify.
  1691      2. It does no longer proceed strictly from left to right but may also
  1692         rotate premises to achieve further simplification.
  1693      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1694      old Asm_full_simp_tac in that it does not rotate premises.
  1695   2. The simplifier now knows a little bit about nat-arithmetic.
  1696 
  1697 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1698 allows for selected deletion of wrappers, by introduction of names for
  1699 wrapper functionals.  This implies that addbefore, addSbefore,
  1700 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1701 and that adding two tactics with the same name overwrites the first
  1702 one (emitting a warning).
  1703   type wrapper = (int -> tactic) -> (int -> tactic)
  1704   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1705   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1706   delWrapper, delSWrapper: claset *  string            -> claset
  1707   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1708 
  1709 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1710 semantics; addbefore now affects only the unsafe part of step_tac
  1711 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1712 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1713 by Force_tac;
  1714 
  1715 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1716 compWrapper; added safe wrapper (and access functions for it);
  1717 
  1718 * HOL/split_all_tac is now much faster and fails if there is nothing
  1719 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1720 and the names of the automatically generated variables have changed.
  1721 split_all_tac has moved within claset() from unsafe wrappers to safe
  1722 wrappers, which means that !!-bound variables are split much more
  1723 aggressively, and safe_tac and clarify_tac now split such variables.
  1724 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1725 Note: the same holds for record_split_tac, which does the job of
  1726 split_all_tac for record fields.
  1727 
  1728 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1729 permanently to the default simpset using Addsplits just like
  1730 Addsimps. They can be removed via Delsplits just like
  1731 Delsimps. Lower-case versions are also available.
  1732 
  1733 * HOL/Simplifier: The rule split_if is now part of the default
  1734 simpset. This means that the simplifier will eliminate all occurrences
  1735 of if-then-else in the conclusion of a goal. To prevent this, you can
  1736 either remove split_if completely from the default simpset by
  1737 `Delsplits [split_if]' or remove it in a specific call of the
  1738 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1739 other case splitting rules to/from the default simpset: every datatype
  1740 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1741 t is the name of the datatype).
  1742 
  1743 * Classical reasoner / Simplifier combination: new force_tac (and
  1744 derivatives Force_tac, force) combines rewriting and classical
  1745 reasoning (and whatever other tools) similarly to auto_tac, but is
  1746 aimed to solve the given subgoal completely.
  1747 
  1748 
  1749 *** General ***
  1750 
  1751 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1752 and `goalw': the theory is no longer needed as an explicit argument -
  1753 the current theory context is used; assumptions are no longer returned
  1754 at the ML-level unless one of them starts with ==> or !!; it is
  1755 recommended to convert to these new commands using isatool fixgoal
  1756 (backup your sources first!);
  1757 
  1758 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1759 the current theory context, and 'theory' to lookup stored theories;
  1760 
  1761 * new theory section 'locale' for declaring constants, assumptions and
  1762 definitions that have local scope;
  1763 
  1764 * new theory section 'nonterminals' for purely syntactic types;
  1765 
  1766 * new theory section 'setup' for generic ML setup functions
  1767 (e.g. package initialization);
  1768 
  1769 * the distribution now includes Isabelle icons: see
  1770 lib/logo/isabelle-{small,tiny}.xpm;
  1771 
  1772 * isatool install - install binaries with absolute references to
  1773 ISABELLE_HOME/bin;
  1774 
  1775 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1776 
  1777 * print mode 'emacs' reserved for Isamode;
  1778 
  1779 * support multiple print (ast) translations per constant name;
  1780 
  1781 * theorems involving oracles are now printed with a suffixed [!];
  1782 
  1783 
  1784 *** HOL ***
  1785 
  1786 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1787 
  1788 * HOL/inductive package reorganized and improved: now supports mutual
  1789 definitions such as
  1790 
  1791   inductive EVEN ODD
  1792     intrs
  1793       null "0 : EVEN"
  1794       oddI "n : EVEN ==> Suc n : ODD"
  1795       evenI "n : ODD ==> Suc n : EVEN"
  1796 
  1797 new theorem list "elims" contains an elimination rule for each of the
  1798 recursive sets; inductive definitions now handle disjunctive premises
  1799 correctly (also ZF);
  1800 
  1801 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1802 "mutual_induct" no longer exists - the induction rule is always
  1803 contained in "induct";
  1804 
  1805 
  1806 * HOL/datatype package re-implemented and greatly improved: now
  1807 supports mutually recursive datatypes such as
  1808 
  1809   datatype
  1810     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1811             | SUM ('a aexp) ('a aexp)
  1812             | DIFF ('a aexp) ('a aexp)
  1813             | NUM 'a
  1814   and
  1815     'a bexp = LESS ('a aexp) ('a aexp)
  1816             | AND ('a bexp) ('a bexp)
  1817             | OR ('a bexp) ('a bexp)
  1818 
  1819 as well as indirectly recursive datatypes such as
  1820 
  1821   datatype
  1822     ('a, 'b) term = Var 'a
  1823                   | App 'b ((('a, 'b) term) list)
  1824 
  1825 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1826 induction on mutually / indirectly recursive datatypes.
  1827 
  1828 Primrec equations are now stored in theory and can be accessed via
  1829 <function_name>.simps.
  1830 
  1831 INCOMPATIBILITIES:
  1832 
  1833   - Theories using datatypes must now have theory Datatype as an
  1834     ancestor.
  1835   - The specific <typename>.induct_tac no longer exists - use the
  1836     generic induct_tac instead.
  1837   - natE has been renamed to nat.exhaust - use exhaust_tac
  1838     instead of res_inst_tac ... natE. Note that the variable
  1839     names in nat.exhaust differ from the names in natE, this
  1840     may cause some "fragile" proofs to fail.
  1841   - The theorems split_<typename>_case and split_<typename>_case_asm
  1842     have been renamed to <typename>.split and <typename>.split_asm.
  1843   - Since default sorts of type variables are now handled correctly,
  1844     some datatype definitions may have to be annotated with explicit
  1845     sort constraints.
  1846   - Primrec definitions no longer require function name and type
  1847     of recursive argument.
  1848 
  1849 Consider using isatool fixdatatype to adapt your theories and proof
  1850 scripts to the new package (backup your sources first!).
  1851 
  1852 
  1853 * HOL/record package: considerably improved implementation; now
  1854 includes concrete syntax for record types, terms, updates; theorems
  1855 for surjective pairing and splitting !!-bound record variables; proof
  1856 support is as follows:
  1857 
  1858   1) standard conversions (selectors or updates applied to record
  1859 constructor terms) are part of the standard simpset;
  1860 
  1861   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1862 made part of standard simpset and claset via addIffs;
  1863 
  1864   3) a tactic for record field splitting (record_split_tac) is part of
  1865 the standard claset (addSWrapper);
  1866 
  1867 To get a better idea about these rules you may retrieve them via
  1868 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1869 the name of your record type.
  1870 
  1871 The split tactic 3) conceptually simplifies by the following rule:
  1872 
  1873   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1874 
  1875 Thus any record variable that is bound by meta-all will automatically
  1876 blow up into some record constructor term, consequently the
  1877 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1878 solve record problems automatically.
  1879 
  1880 
  1881 * reorganized the main HOL image: HOL/Integ and String loaded by
  1882 default; theory Main includes everything;
  1883 
  1884 * automatic simplification of integer sums and comparisons, using cancellation;
  1885 
  1886 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1887 
  1888 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1889 
  1890 * many new identities for unions, intersections, set difference, etc.;
  1891 
  1892 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1893 called split_if, split_split, split_sum_case and split_nat_case (to go
  1894 with add/delsplits);
  1895 
  1896 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1897 (?x::unit) = (); this is made part of the default simpset, which COULD
  1898 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1899 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1900 unit_abs_eta_conv is added in order to counter the effect of
  1901 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1902 %u.f();
  1903 
  1904 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1905 makes more sense);
  1906 
  1907 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1908   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1909   disjointness reasoning but breaking a few old proofs.
  1910 
  1911 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1912 to 'converse' from 'inverse' (for compatibility with ZF and some
  1913 literature);
  1914 
  1915 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1916 the well-founded relation;
  1917 
  1918 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1919     Compl A.  The "Compl" syntax remains available as input syntax for this
  1920     release ONLY.
  1921 
  1922 * HOL/Update: new theory of function updates:
  1923     f(a:=b) == %x. if x=a then b else f x
  1924 may also be iterated as in f(a:=b,c:=d,...);
  1925 
  1926 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1927 
  1928 * HOL/List:
  1929   - new function list_update written xs[i:=v] that updates the i-th
  1930     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1931   - new function `upt' written [i..j(] which generates the list
  1932     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1933     bound write [i..j], which is a shorthand for [i..j+1(].
  1934   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1935 
  1936 * HOL/Arith:
  1937   - removed 'pred' (predecessor) function;
  1938   - generalized some theorems about n-1;
  1939   - many new laws about "div" and "mod";
  1940   - new laws about greatest common divisors (see theory ex/Primes);
  1941 
  1942 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1943 instead of "inverse";
  1944 
  1945 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1946   of the multiset ordering;
  1947 
  1948 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1949   (not included by default);
  1950 
  1951 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1952 
  1953 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1954   programs, i.e. different program variables may have different types.
  1955 
  1956 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1957   [previously, this check worked only if the rewrite rule was unconditional]
  1958   Now rew can involve either definitions or equalities (either == or =).
  1959 
  1960 
  1961 *** ZF ***
  1962 
  1963 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1964   only the theorems proved on ZF.ML;
  1965 
  1966 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1967   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1968   disjointness reasoning but breaking a few old proofs.
  1969 
  1970 * ZF/Update: new theory of function updates
  1971     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1972   may also be iterated as in f(a:=b,c:=d,...);
  1973 
  1974 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1975 
  1976 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1977   [previously, this check worked only if the rewrite rule was unconditional]
  1978   Now rew can involve either definitions or equalities (either == or =).
  1979 
  1980 * case_tac provided for compatibility with HOL
  1981     (like the old excluded_middle_tac, but with subgoals swapped)
  1982 
  1983 
  1984 *** Internal programming interfaces ***
  1985 
  1986 * Pure: several new basic modules made available for general use, see
  1987 also src/Pure/README;
  1988 
  1989 * improved the theory data mechanism to support encapsulation (data
  1990 kind name replaced by private Object.kind, acting as authorization
  1991 key); new type-safe user interface via functor TheoryDataFun; generic
  1992 print_data function becomes basically useless;
  1993 
  1994 * removed global_names compatibility flag -- all theory declarations
  1995 are qualified by default;
  1996 
  1997 * module Pure/Syntax now offers quote / antiquote translation
  1998 functions (useful for Hoare logic etc. with implicit dependencies);
  1999 see HOL/ex/Antiquote for an example use;
  2000 
  2001 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2002 cterm -> thm;
  2003 
  2004 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2005 subgoal;
  2006 
  2007 * Display.print_goals function moved to Locale.print_goals;
  2008 
  2009 * standard print function for goals supports current_goals_markers
  2010 variable for marking begin of proof, end of proof, start of goal; the
  2011 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2012 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2013 for example;
  2014 
  2015 
  2016 
  2017 New in Isabelle98 (January 1998)
  2018 --------------------------------
  2019 
  2020 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2021 
  2022 * changed lexical syntax of terms / types: dots made part of long
  2023 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2024 
  2025 * simpset (and claset) reference variable replaced by functions
  2026 simpset / simpset_ref;
  2027 
  2028 * no longer supports theory aliases (via merge) and non-trivial
  2029 implicit merge of thms' signatures;
  2030 
  2031 * most internal names of constants changed due to qualified names;
  2032 
  2033 * changed Pure/Sequence interface (see Pure/seq.ML);
  2034 
  2035 
  2036 *** General Changes ***
  2037 
  2038 * hierachically structured name spaces (for consts, types, axms, thms
  2039 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2040 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2041 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2042 long_names for fully qualified output names; NOTE: ML programs
  2043 (special tactics, packages etc.) referring to internal names may have
  2044 to be adapted to cope with fully qualified names; in case of severe
  2045 backward campatibility problems try setting 'global_names' at compile
  2046 time to have enrything declared within a flat name space; one may also
  2047 fine tune name declarations in theories via the 'global' and 'local'
  2048 section;
  2049 
  2050 * reimplemented the implicit simpset and claset using the new anytype
  2051 data filed in signatures; references simpset:simpset ref etc. are
  2052 replaced by functions simpset:unit->simpset and
  2053 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2054 to patch your ML files accordingly;
  2055 
  2056 * HTML output now includes theory graph data for display with Java
  2057 applet or isatool browser; data generated automatically via isatool
  2058 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2059 
  2060 * defs may now be conditional; improved rewrite_goals_tac to handle
  2061 conditional equations;
  2062 
  2063 * defs now admits additional type arguments, using TYPE('a) syntax;
  2064 
  2065 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2066 creates a new theory node; implicit merge of thms' signatures is
  2067 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2068 transfer:theory->thm->thm in (rare) cases;
  2069 
  2070 * improved handling of draft signatures / theories; draft thms (and
  2071 ctyps, cterms) are automatically promoted to real ones;
  2072 
  2073 * slightly changed interfaces for oracles: admit many per theory, named
  2074 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2075 
  2076 * print_goals: optional output of const types (set show_consts and
  2077 show_types);
  2078 
  2079 * improved output of warnings (###) and errors (***);
  2080 
  2081 * subgoal_tac displays a warning if the new subgoal has type variables;
  2082 
  2083 * removed old README and Makefiles;
  2084 
  2085 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2086 
  2087 * removed obsolete init_pps and init_database;
  2088 
  2089 * deleted the obsolete tactical STATE, which was declared by
  2090     fun STATE tacfun st = tacfun st st;
  2091 
  2092 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2093 (which abbreviates $HOME);
  2094 
  2095 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2096 use isatool fixseq to adapt your ML programs (this works for fully
  2097 qualified references to the Sequence structure only!);
  2098 
  2099 * use_thy no longer requires writable current directory; it always
  2100 reloads .ML *and* .thy file, if either one is out of date;
  2101 
  2102 
  2103 *** Classical Reasoner ***
  2104 
  2105 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2106 tactics that use classical reasoning to simplify a subgoal without
  2107 splitting it into several subgoals;
  2108 
  2109 * Safe_tac: like safe_tac but uses the default claset;
  2110 
  2111 
  2112 *** Simplifier ***
  2113 
  2114 * added simplification meta rules:
  2115     (asm_)(full_)simplify: simpset -> thm -> thm;
  2116 
  2117 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2118 logics (again);
  2119 
  2120 * added prems argument to simplification procedures;
  2121 
  2122 * HOL, FOL, ZF: added infix function `addsplits':
  2123   instead of `<simpset> setloop (split_tac <thms>)'
  2124   you can simply write `<simpset> addsplits <thms>'
  2125 
  2126 
  2127 *** Syntax ***
  2128 
  2129 * TYPE('a) syntax for type reflection terms;
  2130 
  2131 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2132 
  2133 * pretty printer: changed order of mixfix annotation preference (again!);
  2134 
  2135 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2136 
  2137 
  2138 *** HOL ***
  2139 
  2140 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2141   with `addloop' of the simplifier to faciliate case splitting in premises.
  2142 
  2143 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2144 
  2145 * HOL/Auth: new protocol proofs including some for the Internet
  2146   protocol TLS;
  2147 
  2148 * HOL/Map: new theory of `maps' a la VDM;
  2149 
  2150 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2151 cancelling out common nat summands from =, <, <= (in)equalities, or
  2152 differences; simplification procedures nat_cancel_factor for
  2153 cancelling common factor from =, <, <= (in)equalities over natural
  2154 sums; nat_cancel contains both kinds of procedures, it is installed by
  2155 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2156 
  2157 * HOL/simplifier: terms of the form
  2158   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2159   are rewritten to
  2160   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2161   and those of the form
  2162   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2163   are rewritten to
  2164   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2165 
  2166 * HOL/datatype
  2167   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2168 
  2169   P(t_case f1 ... fn x) =
  2170      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2171         ...
  2172        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2173      )
  2174 
  2175   and a theorem `split_t_case_asm' of the form
  2176 
  2177   P(t_case f1 ... fn x) =
  2178     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2179         ...
  2180        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2181      )
  2182   which can be added to a simpset via `addsplits'. The existing theorems
  2183   expand_list_case and expand_option_case have been renamed to
  2184   split_list_case and split_option_case.
  2185 
  2186 * HOL/Arithmetic:
  2187   - `pred n' is automatically converted to `n-1'.
  2188     Users are strongly encouraged not to use `pred' any longer,
  2189     because it will disappear altogether at some point.
  2190   - Users are strongly encouraged to write "0 < n" rather than
  2191     "n ~= 0". Theorems and proof tools have been modified towards this
  2192     `standard'.
  2193 
  2194 * HOL/Lists:
  2195   the function "set_of_list" has been renamed "set" (and its theorems too);
  2196   the function "nth" now takes its arguments in the reverse order and
  2197   has acquired the infix notation "!" as in "xs!n".
  2198 
  2199 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2200 
  2201 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2202   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2203 
  2204 * HOL/record: extensible records with schematic structural subtyping
  2205 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2206 still lacks various theorems and concrete record syntax;
  2207 
  2208 
  2209 *** HOLCF ***
  2210 
  2211 * removed "axioms" and "generated by" sections;
  2212 
  2213 * replaced "ops" section by extended "consts" section, which is capable of
  2214   handling the continuous function space "->" directly;
  2215 
  2216 * domain package:
  2217   . proves theorems immediately and stores them in the theory,
  2218   . creates hierachical name space,
  2219   . now uses normal mixfix annotations (instead of cinfix...),
  2220   . minor changes to some names and values (for consistency),
  2221   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2222   . separator between mutual domain defs: changed "," to "and",
  2223   . improved handling of sort constraints;  now they have to
  2224     appear on the left-hand side of the equations only;
  2225 
  2226 * fixed LAM <x,y,zs>.b syntax;
  2227 
  2228 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2229 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2230 
  2231 
  2232 *** FOL and ZF ***
  2233 
  2234 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2235   with `addloop' of the simplifier to faciliate case splitting in premises.
  2236 
  2237 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2238 in HOL, they strip ALL and --> from proved theorems;
  2239 
  2240 
  2241 
  2242 New in Isabelle94-8 (May 1997)
  2243 ------------------------------
  2244 
  2245 *** General Changes ***
  2246 
  2247 * new utilities to build / run / maintain Isabelle etc. (in parts
  2248 still somewhat experimental); old Makefiles etc. still functional;
  2249 
  2250 * new 'Isabelle System Manual';
  2251 
  2252 * INSTALL text, together with ./configure and ./build scripts;
  2253 
  2254 * reimplemented type inference for greater efficiency, better error
  2255 messages and clean internal interface;
  2256 
  2257 * prlim command for dealing with lots of subgoals (an easier way of
  2258 setting goals_limit);
  2259 
  2260 
  2261 *** Syntax ***
  2262 
  2263 * supports alternative (named) syntax tables (parser and pretty
  2264 printer); internal interface is provided by add_modesyntax(_i);
  2265 
  2266 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2267 be used in conjunction with the Isabelle symbol font; uses the
  2268 "symbols" syntax table;
  2269 
  2270 * added token_translation interface (may translate name tokens in
  2271 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2272 the current print_mode); IMPORTANT: user print translation functions
  2273 are responsible for marking newly introduced bounds
  2274 (Syntax.mark_boundT);
  2275 
  2276 * token translations for modes "xterm" and "xterm_color" that display
  2277 names in bold, underline etc. or colors (which requires a color
  2278 version of xterm);
  2279 
  2280 * infixes may now be declared with names independent of their syntax;
  2281 
  2282 * added typed_print_translation (like print_translation, but may
  2283 access type of constant);
  2284 
  2285 
  2286 *** Classical Reasoner ***
  2287 
  2288 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2289 some limitations.  Blast_tac...
  2290   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2291   + ignores elimination rules that don't have the correct format
  2292         (the conclusion MUST be a formula variable)
  2293   + ignores types, which can make HOL proofs fail
  2294   + rules must not require higher-order unification, e.g. apply_type in ZF
  2295     [message "Function Var's argument not a bound variable" relates to this]
  2296   + its proof strategy is more general but can actually be slower
  2297 
  2298 * substitution with equality assumptions no longer permutes other
  2299 assumptions;
  2300 
  2301 * minor changes in semantics of addafter (now called addaltern); renamed
  2302 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2303 (and access functions for it);
  2304 
  2305 * improved combination of classical reasoner and simplifier:
  2306   + functions for handling clasimpsets
  2307   + improvement of addss: now the simplifier is called _after_ the
  2308     safe steps.
  2309   + safe variant of addss called addSss: uses safe simplifications
  2310     _during_ the safe steps. It is more complete as it allows multiple
  2311     instantiations of unknowns (e.g. with slow_tac).
  2312 
  2313 *** Simplifier ***
  2314 
  2315 * added interface for simplification procedures (functions that
  2316 produce *proven* rewrite rules on the fly, depending on current
  2317 redex);
  2318 
  2319 * ordering on terms as parameter (used for ordered rewriting);
  2320 
  2321 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2322 
  2323 * the solver is now split into a safe and an unsafe part.
  2324 This should be invisible for the normal user, except that the
  2325 functions setsolver and addsolver have been renamed to setSolver and
  2326 addSolver; added safe_asm_full_simp_tac;
  2327 
  2328 
  2329 *** HOL ***
  2330 
  2331 * a generic induction tactic `induct_tac' which works for all datatypes and
  2332 also for type `nat';
  2333 
  2334 * a generic case distinction tactic `exhaust_tac' which works for all
  2335 datatypes and also for type `nat';
  2336 
  2337 * each datatype comes with a function `size';
  2338 
  2339 * patterns in case expressions allow tuple patterns as arguments to
  2340 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2341 
  2342 * primrec now also works with type nat;
  2343 
  2344 * recdef: a new declaration form, allows general recursive functions to be
  2345 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2346 
  2347 * the constant for negation has been renamed from "not" to "Not" to
  2348 harmonize with FOL, ZF, LK, etc.;
  2349 
  2350 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2351 infinite lists;
  2352 
  2353 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2354 
  2355 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2356 problems in commutative rings, using axiomatic type classes for + and *;
  2357 
  2358 * more examples in HOL/MiniML and HOL/Auth;
  2359 
  2360 * more default rewrite rules for quantifiers, union/intersection;
  2361 
  2362 * a new constant `arbitrary == @x.False';
  2363 
  2364 * HOLCF/IOA replaces old HOL/IOA;
  2365 
  2366 * HOLCF changes: derived all rules and arities
  2367   + axiomatic type classes instead of classes
  2368   + typedef instead of faking type definitions
  2369   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2370   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2371   + eliminated the types void, one, tr
  2372   + use unit lift and bool lift (with translations) instead of one and tr
  2373   + eliminated blift from Lift3.thy (use Def instead of blift)
  2374   all eliminated rules are derived as theorems --> no visible changes ;
  2375 
  2376 
  2377 *** ZF ***
  2378 
  2379 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2380 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2381 as ZF_cs addSIs [equalityI];
  2382 
  2383 
  2384 
  2385 New in Isabelle94-7 (November 96)
  2386 ---------------------------------
  2387 
  2388 * allowing negative levels (as offsets) in prlev and choplev;
  2389 
  2390 * super-linear speedup for large simplifications;
  2391 
  2392 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2393 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2394 FAIL); can suppress it using the command Delsimps (ex_simps @
  2395 all_simps); De Morgan laws are also now included, by default;
  2396 
  2397 * improved printing of ==>  :  ~:
  2398 
  2399 * new object-logic "Sequents" adds linear logic, while replacing LK
  2400 and Modal (thanks to Sara Kalvala);
  2401 
  2402 * HOL/Auth: correctness proofs for authentication protocols;
  2403 
  2404 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2405 examples on HOL/Auth);
  2406 
  2407 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2408 the rewriter and classical reasoner simultaneously;
  2409 
  2410 * function uresult no longer returns theorems in "standard" format;
  2411 regain previous version by: val uresult = standard o uresult;
  2412 
  2413 
  2414 
  2415 New in Isabelle94-6
  2416 -------------------
  2417 
  2418 * oracles -- these establish an interface between Isabelle and trusted
  2419 external reasoners, which may deliver results as theorems;
  2420 
  2421 * proof objects (in particular record all uses of oracles);
  2422 
  2423 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2424 
  2425 * "constdefs" section in theory files;
  2426 
  2427 * "primrec" section (HOL) no longer requires names;
  2428 
  2429 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2430 
  2431 
  2432 
  2433 New in Isabelle94-5
  2434 -------------------
  2435 
  2436 * reduced space requirements;
  2437 
  2438 * automatic HTML generation from theories;
  2439 
  2440 * theory files no longer require "..." (quotes) around most types;
  2441 
  2442 * new examples, including two proofs of the Church-Rosser theorem;
  2443 
  2444 * non-curried (1994) version of HOL is no longer distributed;
  2445 
  2446 
  2447 
  2448 New in Isabelle94-4
  2449 -------------------
  2450 
  2451 * greatly reduced space requirements;
  2452 
  2453 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2454 
  2455 * searchable theorem database (see the section "Retrieving theorems" on
  2456 page 8 of the Reference Manual);
  2457 
  2458 * new examples, including Grabczewski's monumental case study of the
  2459 Axiom of Choice;
  2460 
  2461 * The previous version of HOL renamed to Old_HOL;
  2462 
  2463 * The new version of HOL (previously called CHOL) uses a curried syntax
  2464 for functions.  Application looks like f a b instead of f(a,b);
  2465 
  2466 * Mutually recursive inductive definitions finally work in HOL;
  2467 
  2468 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2469 translates to the operator "split";
  2470 
  2471 
  2472 
  2473 New in Isabelle94-3
  2474 -------------------
  2475 
  2476 * new infix operator, addss, allowing the classical reasoner to
  2477 perform simplification at each step of its search.  Example:
  2478         fast_tac (cs addss ss)
  2479 
  2480 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2481 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2482 look like (a,b) instead of <a,b>;
  2483 
  2484 * PLEASE NOTE: CHOL will eventually replace HOL!
  2485 
  2486 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2487 It translates to the operator "split".  A new theory of integers is available;
  2488 
  2489 * In ZF, integer numerals now denote two's-complement binary integers.
  2490 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2491 
  2492 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2493 of the Axiom of Choice;
  2494 
  2495 
  2496 
  2497 New in Isabelle94-2
  2498 -------------------
  2499 
  2500 * Significantly faster resolution;
  2501 
  2502 * the different sections in a .thy file can now be mixed and repeated
  2503 freely;
  2504 
  2505 * Database of theorems for FOL, HOL and ZF.  New
  2506 commands including qed, qed_goal and bind_thm store theorems in the database.
  2507 
  2508 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2509 a given theory (thms_of), or find out what theory a theorem was proved in
  2510 (theory_of_thm);
  2511 
  2512 * Bugs fixed in the inductive definition and datatype packages;
  2513 
  2514 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2515 and HOL_dup_cs obsolete;
  2516 
  2517 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2518 have been removed;
  2519 
  2520 * Simpler definition of function space in ZF;
  2521 
  2522 * new results about cardinal and ordinal arithmetic in ZF;
  2523 
  2524 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2525 types;
  2526 
  2527 
  2528 $Id$