NEWS
author paulson
Mon Feb 16 15:24:03 2004 +0100 (2004-02-16)
changeset 14389 57c2d90936ba
parent 14380 04b603a6f17d
child 14398 c5c47703f763
permissions -rw-r--r--
arith
     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 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws, 
    81     all proved in axiomatic type classes for semirings, rings and fields.
    82 
    83 * Numerics:
    84   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
    85     now formalized using the Ring_and_Field theory mentioned above. 
    86   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
    87     than before, because now they are set up once in a generic manner.
    88   - INCOMPATIBILITY: many type-specific instances of laws proved in 
    89     Ring_and_Field are no longer available.
    90 
    91 * Type "rat" of the rational numbers is now availabe in HOL-Complex.
    92 
    93 * Records:
    94   - Record types are now by default printed with their type abbreviation
    95     instead of the list of all field types. This can be configured via
    96     the reference "print_record_type_abbr".
    97   - Simproc "record_upd_simproc" for simplification of multiple updates added 
    98     (not enabled by default).
    99   - Tactic "record_split_simp_tac" to split and simplify records added.
   100  
   101 * 'specification' command added, allowing for definition by
   102   specification.  There is also an 'ax_specification' command that
   103   introduces the new constants axiomatically.
   104 
   105 * arith(_tac) is now able to generate counterexamples for reals as well.
   106 
   107 * SET-Protocol: formalization and verification of the SET protocol suite;
   108 
   109 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   110  defintions, thanks to Sava Krsti\'{c} and John Matthews.
   111 
   112 * Unions and Intersections:
   113   The x-symbol output syntax of UN and INT has been changed
   114   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   115   i.e. the index formulae has become a subscript, like in normal math.
   116   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   117   The subscript version is also accepted as input syntax.
   118 
   119 
   120 New in Isabelle2003 (May 2003)
   121 --------------------------------
   122 
   123 *** General ***
   124 
   125 * Provers/simplifier:
   126 
   127   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   128     Assumptions are now subject to complete mutual simplification,
   129     not just from left to right. The simplifier now preserves
   130     the order of assumptions.
   131 
   132     Potential INCOMPATIBILITY:
   133 
   134     -- simp sometimes diverges where the old version did
   135        not, e.g. invoking simp on the goal
   136 
   137         [| P (f x); y = x; f x = f y |] ==> Q
   138 
   139        now gives rise to the infinite reduction sequence
   140 
   141         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   142 
   143        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   144        kind of problem.
   145 
   146     -- Tactics combining classical reasoner and simplification (such as auto)
   147        are also affected by this change, because many of them rely on
   148        simp. They may sometimes diverge as well or yield a different numbers
   149        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   150        in case of problems. Sometimes subsequent calls to the classical
   151        reasoner will fail because a preceeding call to the simplifier too
   152        eagerly simplified the goal, e.g. deleted redundant premises.
   153 
   154   - The simplifier trace now shows the names of the applied rewrite rules
   155 
   156   - You can limit the number of recursive invocations of the simplifier
   157     during conditional rewriting (where the simplifie tries to solve the
   158     conditions before applying the rewrite rule):
   159     ML "simp_depth_limit := n"
   160     where n is an integer. Thus you can force termination where previously
   161     the simplifier would diverge.
   162 
   163   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   164 
   165   - No longer aborts on failed congruence proof.  Instead, the
   166     congruence is ignored.
   167 
   168 * Pure: New generic framework for extracting programs from constructive
   169   proofs. See HOL/Extraction.thy for an example instantiation, as well
   170   as HOL/Extraction for some case studies.
   171 
   172 * Pure: The main goal of the proof state is no longer shown by default, only
   173 the subgoals. This behaviour is controlled by a new flag.
   174    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   175 (ML: Proof.show_main_goal).
   176 
   177 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   178 rules whose conclusion matches subgoal 1:
   179       PG menu: Isabelle/Isar -> Show me -> matching rules
   180 The rules are ordered by how closely they match the subgoal.
   181 In particular, rules that solve a subgoal outright are displayed first
   182 (or rather last, the way they are printed).
   183 (ML: ProofGeneral.print_intros())
   184 
   185 * Pure: New flag trace_unify_fail causes unification to print
   186 diagnostic information (PG: in trace buffer) when it fails. This is
   187 useful for figuring out why single step proofs like rule, erule or
   188 assumption failed.
   189 
   190 * Pure: Locale specifications now produce predicate definitions
   191 according to the body of text (covering assumptions modulo local
   192 definitions); predicate "loc_axioms" covers newly introduced text,
   193 while "loc" is cumulative wrt. all included locale expressions; the
   194 latter view is presented only on export into the global theory
   195 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   196 on the old view without predicates;
   197 
   198 * Pure: predefined locales "var" and "struct" are useful for sharing
   199 parameters (as in CASL, for example); just specify something like
   200 ``var x + var y + struct M'' as import;
   201 
   202 * Pure: improved thms_containing: proper indexing of facts instead of
   203 raw theorems; check validity of results wrt. current name space;
   204 include local facts of proof configuration (also covers active
   205 locales), cover fixed variables in index; may use "_" in term
   206 specification; an optional limit for the number of printed facts may
   207 be given (the default is 40);
   208 
   209 * Pure: disallow duplicate fact bindings within new-style theory files
   210 (batch-mode only);
   211 
   212 * Provers: improved induct method: assumptions introduced by case
   213 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   214 the goal statement); "foo" still refers to all facts collectively;
   215 
   216 * Provers: the function blast.overloaded has been removed: all constants
   217 are regarded as potentially overloaded, which improves robustness in exchange
   218 for slight decrease in efficiency;
   219 
   220 * Provers/linorder: New generic prover for transitivity reasoning over
   221 linear orders.  Note: this prover is not efficient!
   222 
   223 * Isar: preview of problems to finish 'show' now produce an error
   224 rather than just a warning (in interactive mode);
   225 
   226 
   227 *** HOL ***
   228 
   229 * arith(_tac)
   230 
   231  - Produces a counter example if it cannot prove a goal.
   232    Note that the counter example may be spurious if the goal is not a formula
   233    of quantifier-free linear arithmetic.
   234    In ProofGeneral the counter example appears in the trace buffer.
   235 
   236  - Knows about div k and mod k where k is a numeral of type nat or int.
   237 
   238  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   239    linear arithmetic fails. This takes account of quantifiers and divisibility.
   240    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   241 
   242 * simp's arithmetic capabilities have been enhanced a bit: it now
   243 takes ~= in premises into account (by performing a case split);
   244 
   245 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   246 are distributed over a sum of terms;
   247 
   248 * New tactic "trans_tac" and method "trans" instantiate
   249 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   250 "<=", "<" and "="). 
   251 
   252 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   253 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   254 
   255 * 'typedef' command has new option "open" to suppress the set
   256 definition;
   257 
   258 * functions Min and Max on finite sets have been introduced (theory
   259 Finite_Set);
   260 
   261 * attribute [symmetric] now works for relations as well; it turns
   262 (x,y) : R^-1 into (y,x) : R, and vice versa;
   263 
   264 * induct over a !!-quantified statement (say !!x1..xn):
   265   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   266 
   267 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   268 %x. None. Warning: empty_def now refers to the previously hidden definition
   269 of the empty set.
   270 
   271 * Algebra: formalization of classical algebra.  Intended as base for
   272 any algebraic development in Isabelle.  Currently covers group theory
   273 (up to Sylow's theorem) and ring theory (Universal Property of
   274 Univariate Polynomials).  Contributions welcome;
   275 
   276 * GroupTheory: deleted, since its material has been moved to Algebra;
   277 
   278 * Complex: new directory of the complex numbers with numeric constants, 
   279 nonstandard complex numbers, and some complex analysis, standard and 
   280 nonstandard (Jacques Fleuriot);
   281 
   282 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   283 
   284 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   285 Fleuriot);
   286 
   287 * Real/HahnBanach: updated and adapted to locales;
   288 
   289 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   290 Gray and Kramer);
   291 
   292 * UNITY: added the Meier-Sanders theory of progress sets;
   293 
   294 * MicroJava: bytecode verifier and lightweight bytecode verifier
   295 as abstract algorithms, instantiated to the JVM;
   296 
   297 * Bali: Java source language formalization. Type system, operational
   298 semantics, axiomatic semantics. Supported language features:
   299 classes, interfaces, objects,virtual methods, static methods,
   300 static/instance fields, arrays, access modifiers, definite
   301 assignment, exceptions.
   302 
   303 
   304 *** ZF ***
   305 
   306 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   307 universe, etc.);
   308 
   309 * Main ZF: virtually all theories converted to new-style format;
   310 
   311 
   312 *** ML ***
   313 
   314 * Pure: Tactic.prove provides sane interface for internal proofs;
   315 omits the infamous "standard" operation, so this is more appropriate
   316 than prove_goalw_cterm in many situations (e.g. in simprocs);
   317 
   318 * Pure: improved error reporting of simprocs;
   319 
   320 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   321 up simprocs;
   322 
   323 
   324 *** Document preparation ***
   325 
   326 * uses \par instead of \\ for line breaks in theory text. This may
   327 shift some page breaks in large documents. To get the old behaviour
   328 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   329 
   330 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   331 other packages
   332 
   333 * \<euro> now needs package babel/greek instead of marvosym (which
   334 broke \Rightarrow)
   335 
   336 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   337 textcomp package)
   338 
   339 
   340 New in Isabelle2002 (March 2002)
   341 --------------------------------
   342 
   343 *** Document preparation ***
   344 
   345 * greatly simplified document preparation setup, including more
   346 graceful interpretation of isatool usedir -i/-d/-D options, and more
   347 instructive isatool mkdir; users should basically be able to get
   348 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   349 users may run a separate document processing stage manually like this:
   350 "isatool usedir -D output HOL Test && isatool document Test/output";
   351 
   352 * theory dependency graph may now be incorporated into documents;
   353 isatool usedir -g true will produce session_graph.eps/.pdf for use
   354 with \includegraphics of LaTeX;
   355 
   356 * proper spacing of consecutive markup elements, especially text
   357 blocks after section headings;
   358 
   359 * support bold style (for single symbols only), input syntax is like
   360 this: "\<^bold>\<alpha>" or "\<^bold>A";
   361 
   362 * \<bullet> is now output as bold \cdot by default, which looks much
   363 better in printed text;
   364 
   365 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   366 note that these symbols are currently unavailable in Proof General /
   367 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   368 
   369 * isatool latex no longer depends on changed TEXINPUTS, instead
   370 isatool document copies the Isabelle style files to the target
   371 location;
   372 
   373 
   374 *** Isar ***
   375 
   376 * Pure/Provers: improved proof by cases and induction;
   377   - 'case' command admits impromptu naming of parameters (such as
   378     "case (Suc n)");
   379   - 'induct' method divinates rule instantiation from the inductive
   380     claim; no longer requires excessive ?P bindings for proper
   381     instantiation of cases;
   382   - 'induct' method properly enumerates all possibilities of set/type
   383     rules; as a consequence facts may be also passed through *type*
   384     rules without further ado;
   385   - 'induct' method now derives symbolic cases from the *rulified*
   386     rule (before it used to rulify cases stemming from the internal
   387     atomized version); this means that the context of a non-atomic
   388     statement becomes is included in the hypothesis, avoiding the
   389     slightly cumbersome show "PROP ?case" form;
   390   - 'induct' may now use elim-style induction rules without chaining
   391     facts, using ``missing'' premises from the goal state; this allows
   392     rules stemming from inductive sets to be applied in unstructured
   393     scripts, while still benefitting from proper handling of non-atomic
   394     statements; NB: major inductive premises need to be put first, all
   395     the rest of the goal is passed through the induction;
   396   - 'induct' proper support for mutual induction involving non-atomic
   397     rule statements (uses the new concept of simultaneous goals, see
   398     below);
   399   - append all possible rule selections, but only use the first
   400     success (no backtracking);
   401   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   402   - undeclared rule case names default to numbers 1, 2, 3, ...;
   403   - added 'print_induct_rules' (covered by help item in recent Proof
   404     General versions);
   405   - moved induct/cases attributes to Pure, methods to Provers;
   406   - generic method setup instantiated for FOL and HOL;
   407 
   408 * Pure: support multiple simultaneous goal statements, for example
   409 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   410 meta-level mechanism, this acts as if several individual goals had
   411 been stated separately; in particular common proof methods need to be
   412 repeated in order to cover all claims; note that a single elimination
   413 step is *not* sufficient to establish the two conjunctions, so this
   414 fails:
   415 
   416   assume "A & B" then have A and B ..   (*".." fails*)
   417 
   418 better use "obtain" in situations as above; alternative refer to
   419 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   420 
   421 * Pure: proper integration with ``locales''; unlike the original
   422 version by Florian Kammüller, Isar locales package high-level proof
   423 contexts rather than raw logical ones (e.g. we admit to include
   424 attributes everywhere); operations on locales include merge and
   425 rename; support for implicit arguments (``structures''); simultaneous
   426 type-inference over imports and text; see also HOL/ex/Locales.thy for
   427 some examples;
   428 
   429 * Pure: the following commands have been ``localized'', supporting a
   430 target locale specification "(in name)": 'lemma', 'theorem',
   431 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   432 stored both within the locale and at the theory level (exported and
   433 qualified by the locale name);
   434 
   435 * Pure: theory goals may now be specified in ``long'' form, with
   436 ad-hoc contexts consisting of arbitrary locale elements. for example
   437 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   438 definitions may be given, too); the result is a meta-level rule with
   439 the context elements being discharged in the obvious way;
   440 
   441 * Pure: new proof command 'using' allows to augment currently used
   442 facts after a goal statement ('using' is syntactically analogous to
   443 'apply', but acts on the goal's facts only); this allows chained facts
   444 to be separated into parts given before and after a claim, as in
   445 ``from a and b have C using d and e <proof>'';
   446 
   447 * Pure: renamed "antecedent" case to "rule_context";
   448 
   449 * Pure: new 'judgment' command records explicit information about the
   450 object-logic embedding (used by several tools internally); no longer
   451 use hard-wired "Trueprop";
   452 
   453 * Pure: added 'corollary' command;
   454 
   455 * Pure: fixed 'token_translation' command;
   456 
   457 * Pure: removed obsolete 'exported' attribute;
   458 
   459 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   460 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   461 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   462 
   463 * Pure: method 'atomize' presents local goal premises as object-level
   464 statements (atomic meta-level propositions); setup controlled via
   465 rewrite rules declarations of 'atomize' attribute; example
   466 application: 'induct' method with proper rule statements in improper
   467 proof *scripts*;
   468 
   469 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   470 now consider the syntactic context of assumptions, giving a better
   471 chance to get type-inference of the arguments right (this is
   472 especially important for locales);
   473 
   474 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   475 mode;
   476 
   477 * Pure/obtain: the formal conclusion "thesis", being marked as
   478 ``internal'', may no longer be reference directly in the text;
   479 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   480 situations;
   481 
   482 * Pure: generic 'sym' attribute which declares a rule both as pure
   483 'elim?' and for the 'symmetric' operation;
   484 
   485 * Pure: marginal comments ``--'' may now occur just anywhere in the
   486 text; the fixed correlation with particular command syntax has been
   487 discontinued;
   488 
   489 * Pure: new method 'rules' is particularly well-suited for proof
   490 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   491 but often produces more compact proof terms with less detours;
   492 
   493 * Pure/Provers/classical: simplified integration with pure rule
   494 attributes and methods; the classical "intro?/elim?/dest?"
   495 declarations coincide with the pure ones; the "rule" method no longer
   496 includes classically swapped intros; "intro" and "elim" methods no
   497 longer pick rules from the context; also got rid of ML declarations
   498 AddXIs/AddXEs/AddXDs; all of this has some potential for
   499 INCOMPATIBILITY;
   500 
   501 * Provers/classical: attribute 'swapped' produces classical inversions
   502 of introduction rules;
   503 
   504 * Provers/simplifier: 'simplified' attribute may refer to explicit
   505 rules instead of full simplifier context; 'iff' attribute handles
   506 conditional rules;
   507 
   508 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   509 
   510 * HOL: 'recdef' now fails on unfinished automated proofs, use
   511 "(permissive)" option to recover old behavior;
   512 
   513 * HOL: 'inductive' no longer features separate (collective) attributes
   514 for 'intros' (was found too confusing);
   515 
   516 * HOL: properly declared induction rules less_induct and
   517 wf_induct_rule;
   518 
   519 
   520 *** HOL ***
   521 
   522 * HOL: moved over to sane numeral syntax; the new policy is as
   523 follows:
   524 
   525   - 0 and 1 are polymorphic constants, which are defined on any
   526   numeric type (nat, int, real etc.);
   527 
   528   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   529   binary representation internally;
   530 
   531   - type nat has special constructor Suc, and generally prefers Suc 0
   532   over 1::nat and Suc (Suc 0) over 2::nat;
   533 
   534 This change may cause significant problems of INCOMPATIBILITY; here
   535 are some hints on converting existing sources:
   536 
   537   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   538   entities, so expressions involving "-" (unary or binary minus) need
   539   to be spaced properly;
   540 
   541   - existing occurrences of "1" may need to be constraint "1::nat" or
   542   even replaced by Suc 0; similar for old "2";
   543 
   544   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   545 
   546   - remove all special provisions on numerals in proofs;
   547 
   548 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   549 representation (depends on bin_arith_simps in the default context);
   550 
   551 * HOL: symbolic syntax for x^2 (numeral 2);
   552 
   553 * HOL: the class of all HOL types is now called "type" rather than
   554 "term"; INCOMPATIBILITY, need to adapt references to this type class
   555 in axclass/classes, instance/arities, and (usually rare) occurrences
   556 in typings (of consts etc.); internally the class is called
   557 "HOL.type", ML programs should refer to HOLogic.typeS;
   558 
   559 * HOL/record package improvements:
   560   - new derived operations "fields" to build a partial record section,
   561     "extend" to promote a fixed record to a record scheme, and
   562     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   563     declared as simp by default;
   564   - shared operations ("more", "fields", etc.) now need to be always
   565     qualified) --- potential INCOMPATIBILITY;
   566   - removed "make_scheme" operations (use "make" with "extend") --
   567     INCOMPATIBILITY;
   568   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   569   - provides cases/induct rules for use with corresponding Isar
   570     methods (for concrete records, record schemes, concrete more
   571     parts, and schematic more parts -- in that order);
   572   - internal definitions directly based on a light-weight abstract
   573     theory of product types over typedef rather than datatype;
   574 
   575 * HOL: generic code generator for generating executable ML code from
   576 specifications; specific support for HOL constructs such as inductive
   577 datatypes and sets, as well as recursive functions; can be invoked
   578 via 'generate_code' theory section;
   579 
   580 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   581 
   582 * HOL: consolidated and renamed several theories.  In particular:
   583 	Ord.thy has been absorbed into HOL.thy
   584 	String.thy has been absorbed into List.thy
   585  
   586 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   587 (beware of argument permutation!);
   588 
   589 * HOL: linorder_less_split superseded by linorder_cases;
   590 
   591 * HOL/List: "nodups" renamed to "distinct";
   592 
   593 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   594 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   595   - Ex_def has changed, now need to use some_eq_ex
   596 
   597 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   598 in this (rare) case use:
   599 
   600   delSWrapper "split_all_tac"
   601   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   602 
   603 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   604 MAY FAIL;
   605 
   606 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   607 Isabelle's type classes, ^ on functions and relations has too general
   608 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   609 necessary to attach explicit type constraints;
   610 
   611 * HOL/Relation: the prefix name of the infix "O" has been changed from
   612 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   613 renamed accordingly (eg "compI" -> "rel_compI").
   614 
   615 * HOL: syntax translations now work properly with numerals and records
   616 expressions;
   617 
   618 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   619 of "lam" -- INCOMPATIBILITY;
   620 
   621 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   622 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   623 renamed "Product_Type.unit";
   624 
   625 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   626 
   627 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   628 the "cases" method);
   629 
   630 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   631 Florian Kammüller);
   632 
   633 * HOL/IMP: updated and converted to new-style theory format; several
   634 parts turned into readable document, with proper Isar proof texts and
   635 some explanations (by Gerwin Klein);
   636 
   637 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   638 
   639 * HOL-Hyperreal is now a logic image;
   640 
   641 
   642 *** HOLCF ***
   643 
   644 * Isar: consts/constdefs supports mixfix syntax for continuous
   645 operations;
   646 
   647 * Isar: domain package adapted to new-style theory format, e.g. see
   648 HOLCF/ex/Dnat.thy;
   649 
   650 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   651 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   652 lift.induct_tac, always use UU instead of Undef;
   653 
   654 * HOLCF/IMP: updated and converted to new-style theory;
   655 
   656 
   657 *** ZF ***
   658 
   659 * Isar: proper integration of logic-specific tools and packages,
   660 including theory commands '(co)inductive', '(co)datatype',
   661 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   662 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   663 
   664 * theory Main no longer includes AC; for the Axiom of Choice, base
   665 your theory on Main_ZFC;
   666 
   667 * the integer library now covers quotients and remainders, with many
   668 laws relating division to addition, multiplication, etc.;
   669 
   670 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   671 typeless version of the formalism;
   672 
   673 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   674 format;
   675 
   676 * ZF/Induct: new directory for examples of inductive definitions,
   677 including theory Multiset for multiset orderings; converted to
   678 new-style theory format;
   679 
   680 * ZF: many new theorems about lists, ordinals, etc.;
   681 
   682 
   683 *** General ***
   684 
   685 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   686 variable proof controls level of detail: 0 = no proofs (only oracle
   687 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   688 also ref manual for further ML interfaces;
   689 
   690 * Pure/axclass: removed obsolete ML interface
   691 goal_subclass/goal_arity;
   692 
   693 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   694 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   695 separate tokens, so expressions involving minus need to be spaced
   696 properly;
   697 
   698 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   699 rather than "infixl" or "infixr";
   700 
   701 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   702 sort constraint specifications in type inference; e.g. "x::_::foo"
   703 ensures that the type of "x" is of sort "foo" (but not necessarily a
   704 type variable);
   705 
   706 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   707 control output of nested => (types); the default behavior is
   708 "type_brackets";
   709 
   710 * Pure/syntax: builtin parse translation for "_constify" turns valued
   711 tokens into AST constants;
   712 
   713 * Pure/syntax: prefer later declarations of translations and print
   714 translation functions; potential INCOMPATIBILITY: need to reverse
   715 multiple declarations for same syntax element constant;
   716 
   717 * Pure/show_hyps reset by default (in accordance to existing Isar
   718 practice);
   719 
   720 * Provers/classical: renamed addaltern to addafter, addSaltern to
   721 addSafter;
   722 
   723 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   724 as well;
   725 
   726 * system: tested support for MacOS X; should be able to get Isabelle +
   727 Proof General to work in a plain Terminal after installing Poly/ML
   728 (e.g. from the Isabelle distribution area) and GNU bash alone
   729 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   730 support requires further installations, e.g. from
   731 http://fink.sourceforge.net/);
   732 
   733 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   734 
   735 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   736 of 40 MB), cf. ML_OPTIONS;
   737 
   738 * system: Proof General keywords specification is now part of the
   739 Isabelle distribution (see etc/isar-keywords.el);
   740 
   741 * system: support for persistent Proof General sessions (refrain from
   742 outdating all loaded theories on startup); user may create writable
   743 logic images like this: ``isabelle -q HOL Test'';
   744 
   745 * system: smart selection of Isabelle process versus Isabelle
   746 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   747 run both "isabelle" and "Isabelle" even if file names are badly
   748 damaged (executable inspects the case of the first letter of its own
   749 name); added separate "isabelle-process" and "isabelle-interface";
   750 
   751 * system: refrain from any attempt at filtering input streams; no
   752 longer support ``8bit'' encoding of old isabelle font, instead proper
   753 iso-latin characters may now be used; the related isatools
   754 "symbolinput" and "nonascii" have disappeared as well;
   755 
   756 * system: removed old "xterm" interface (the print modes "xterm" and
   757 "xterm_color" are still available for direct use in a suitable
   758 terminal);
   759 
   760 
   761 
   762 New in Isabelle99-2 (February 2001)
   763 -----------------------------------
   764 
   765 *** Overview of INCOMPATIBILITIES ***
   766 
   767 * HOL: please note that theories in the Library and elsewhere often use the
   768 new-style (Isar) format; to refer to their theorems in an ML script you must
   769 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   770 
   771 * HOL: inductive package no longer splits induction rule aggressively,
   772 but only as far as specified by the introductions given; the old
   773 format may be recovered via ML function complete_split_rule or attribute
   774 'split_rule (complete)';
   775 
   776 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   777 gfp_Tarski to gfp_unfold;
   778 
   779 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   780 
   781 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   782 relation); infix "^^" has been renamed "``"; infix "``" has been
   783 renamed "`"; "univalent" has been renamed "single_valued";
   784 
   785 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   786 operation;
   787 
   788 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   789 
   790 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   791 
   792 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   793 consequence, it is no longer monotonic wrt. the local goal context
   794 (which is now passed through the inductive cases);
   795 
   796 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   797 \<gg> to \<ggreater>;
   798 
   799 
   800 *** Document preparation ***
   801 
   802 * \isabellestyle{NAME} selects version of Isabelle output (currently
   803 available: are "it" for near math-mode best-style output, "sl" for
   804 slanted text style, and "tt" for plain type-writer; if no
   805 \isabellestyle command is given, output is according to slanted
   806 type-writer);
   807 
   808 * support sub/super scripts (for single symbols only), input syntax is
   809 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   810 
   811 * some more standard symbols; see Appendix A of the system manual for
   812 the complete list of symbols defined in isabellesym.sty;
   813 
   814 * improved isabelle style files; more abstract symbol implementation
   815 (should now use \isamath{...} and \isatext{...} in custom symbol
   816 definitions);
   817 
   818 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   819 state; Note that presentation of goal states does not conform to
   820 actual human-readable proof documents.  Please do not include goal
   821 states into document output unless you really know what you are doing!
   822 
   823 * proper indentation of antiquoted output with proportional LaTeX
   824 fonts;
   825 
   826 * no_document ML operator temporarily disables LaTeX document
   827 generation;
   828 
   829 * isatool unsymbolize tunes sources for plain ASCII communication;
   830 
   831 
   832 *** Isar ***
   833 
   834 * Pure: Isar now suffers initial goal statements to contain unbound
   835 schematic variables (this does not conform to actual readable proof
   836 documents, due to unpredictable outcome and non-compositional proof
   837 checking); users who know what they are doing may use schematic goals
   838 for Prolog-style synthesis of proven results;
   839 
   840 * Pure: assumption method (an implicit finishing) now handles actual
   841 rules as well;
   842 
   843 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   844 initial goal, declare "that" only as Pure intro (only for single
   845 steps); the "that" rule assumption may now be involved in implicit
   846 finishing, thus ".." becomes a feasible for trivial obtains;
   847 
   848 * Pure: default proof step now includes 'intro_classes'; thus trivial
   849 instance proofs may be performed by "..";
   850 
   851 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   852 statements as well;
   853 
   854 * Pure: more robust selection of calculational rules;
   855 
   856 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   857 rule (as well as the assumption rule);
   858 
   859 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   860 lemmas, using the graph browser tool;
   861 
   862 * Pure: predict failure of "show" in interactive mode;
   863 
   864 * Pure: 'thms_containing' now takes actual terms as arguments;
   865 
   866 * HOL: improved method 'induct' --- now handles non-atomic goals
   867 (potential INCOMPATIBILITY); tuned error handling;
   868 
   869 * HOL: cases and induct rules now provide explicit hints about the
   870 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   871 any remaining facts are inserted into the goal verbatim;
   872 
   873 * HOL: local contexts (aka cases) may now contain term bindings as
   874 well; the 'cases' and 'induct' methods new provide a ?case binding for
   875 the result to be shown in each case;
   876 
   877 * HOL: added 'recdef_tc' command;
   878 
   879 * isatool convert assists in eliminating legacy ML scripts;
   880 
   881 
   882 *** HOL ***
   883 
   884 * HOL/Library: a collection of generic theories to be used together
   885 with main HOL; the theory loader path already includes this directory
   886 by default; the following existing theories have been moved here:
   887 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   888 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   889 
   890 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   891 modelling and verification task performed in Isabelle/HOL +
   892 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   893 
   894 * HOL/Algebra: special summation operator SUM no longer exists, it has
   895 been replaced by setsum; infix 'assoc' now has priority 50 (like
   896 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   897 'domain', this makes the theory consistent with mathematical
   898 literature;
   899 
   900 * HOL basics: added overloaded operations "inverse" and "divide"
   901 (infix "/"), syntax for generic "abs" operation, generic summation
   902 operator \<Sum>;
   903 
   904 * HOL/typedef: simplified package, provide more useful rules (see also
   905 HOL/subset.thy);
   906 
   907 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   908 now expressed as a proper nested rule (old-style tactic scripts may
   909 require atomize_strip_tac to cope with non-atomic premises);
   910 
   911 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   912 to "split_conv" (old name still available for compatibility);
   913 
   914 * HOL: improved concrete syntax for strings (e.g. allows translation
   915 rules with string literals);
   916 
   917 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   918  and Fleuriot's mechanization of analysis, including the transcendental
   919  functions for the reals;
   920 
   921 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   922 
   923 
   924 *** CTT ***
   925 
   926 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   927 "lam" is displayed as TWO lambda-symbols
   928 
   929 * CTT: theory Main now available, containing everything (that is, Bool
   930 and Arith);
   931 
   932 
   933 *** General ***
   934 
   935 * Pure: the Simplifier has been implemented properly as a derived rule
   936 outside of the actual kernel (at last!); the overall performance
   937 penalty in practical applications is about 50%, while reliability of
   938 the Isabelle inference kernel has been greatly improved;
   939 
   940 * print modes "brackets" and "no_brackets" control output of nested =>
   941 (types) and ==> (props); the default behaviour is "brackets";
   942 
   943 * Provers: fast_tac (and friends) now handle actual object-logic rules
   944 as assumptions as well;
   945 
   946 * system: support Poly/ML 4.0;
   947 
   948 * system: isatool install handles KDE version 1 or 2;
   949 
   950 
   951 
   952 New in Isabelle99-1 (October 2000)
   953 ----------------------------------
   954 
   955 *** Overview of INCOMPATIBILITIES ***
   956 
   957 * HOL: simplification of natural numbers is much changed; to partly
   958 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   959 issue the following ML commands:
   960 
   961   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   962   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   963 
   964 * HOL: simplification no longer dives into case-expressions; this is
   965 controlled by "t.weak_case_cong" for each datatype t;
   966 
   967 * HOL: nat_less_induct renamed to less_induct;
   968 
   969 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   970 fixsome to patch .thy and .ML sources automatically;
   971 
   972   select_equality  -> some_equality
   973   select_eq_Ex     -> some_eq_ex
   974   selectI2EX       -> someI2_ex
   975   selectI2         -> someI2
   976   selectI          -> someI
   977   select1_equality -> some1_equality
   978   Eps_sym_eq       -> some_sym_eq_trivial
   979   Eps_eq           -> some_eq_trivial
   980 
   981 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   982 
   983 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   984 instead);
   985 
   986 * HOL: the recursion equations generated by 'recdef' are now called
   987 f.simps instead of f.rules;
   988 
   989 * HOL: qed_spec_mp now also handles bounded ALL as well;
   990 
   991 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   992 sometimes be needed;
   993 
   994 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   995 
   996 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   997 
   998 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   999 product is now "<*>" instead of "Times"; the lexicographic product is
  1000 now "<*lex*>" instead of "**";
  1001 
  1002 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1003 of main HOL, but was unused); better use HOL's datatype package;
  1004 
  1005 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1006 the old syntax may be recovered as follows:
  1007 
  1008   syntax (symbols)
  1009     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1010       (infixl "\\<oplus>" 100)
  1011 
  1012 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1013 
  1014 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1015 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1016 internally;
  1017 
  1018 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1019 changed from A/r to A//r;
  1020 
  1021 * ZF: new treatment of arithmetic (nat & int) may break some old
  1022 proofs;
  1023 
  1024 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1025 rulify -> rule_format, elimify -> elim_format, ...);
  1026 
  1027 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1028 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1029 should have to change intro!! to intro? only); replaced "delrule" by
  1030 "rule del";
  1031 
  1032 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1033 
  1034 * Provers: strengthened force_tac by using new first_best_tac;
  1035 
  1036 * LaTeX document preparation: several changes of isabelle.sty (see
  1037 lib/texinputs);
  1038 
  1039 
  1040 *** Document preparation ***
  1041 
  1042 * formal comments (text blocks etc.) in new-style theories may now
  1043 contain antiquotations of thm/prop/term/typ/text to be presented
  1044 according to latex print mode; concrete syntax is like this:
  1045 @{term[show_types] "f(x) = a + x"};
  1046 
  1047 * isatool mkdir provides easy setup of Isabelle session directories,
  1048 including proper document sources;
  1049 
  1050 * generated LaTeX sources are now deleted after successful run
  1051 (isatool document -c); may retain a copy somewhere else via -D option
  1052 of isatool usedir;
  1053 
  1054 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1055 style files, achieving self-contained LaTeX sources and simplifying
  1056 LaTeX debugging;
  1057 
  1058 * old-style theories now produce (crude) LaTeX output as well;
  1059 
  1060 * browser info session directories are now self-contained (may be put
  1061 on WWW server seperately); improved graphs of nested sessions; removed
  1062 graph for 'all sessions';
  1063 
  1064 * several improvements in isabelle style files; \isabellestyle{it}
  1065 produces fake math mode output; \isamarkupheader is now \section by
  1066 default; see lib/texinputs/isabelle.sty etc.;
  1067 
  1068 
  1069 *** Isar ***
  1070 
  1071 * Isar/Pure: local results and corresponding term bindings are now
  1072 subject to Hindley-Milner polymorphism (similar to ML); this
  1073 accommodates incremental type-inference very nicely;
  1074 
  1075 * Isar/Pure: new derived language element 'obtain' supports
  1076 generalized existence reasoning;
  1077 
  1078 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1079 support accumulation of results, without applying any rules yet;
  1080 useful to collect intermediate results without explicit name
  1081 references, and for use with transitivity rules with more than 2
  1082 premises;
  1083 
  1084 * Isar/Pure: scalable support for case-analysis type proofs: new
  1085 'case' language element refers to local contexts symbolically, as
  1086 produced by certain proof methods; internally, case names are attached
  1087 to theorems as "tags";
  1088 
  1089 * Isar/Pure: theory command 'hide' removes declarations from
  1090 class/type/const name spaces;
  1091 
  1092 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1093 indicate potential overloading;
  1094 
  1095 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1096 
  1097 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1098 "{a,b,c}" instead of {a,b,c};
  1099 
  1100 * Isar/Pure now provides its own version of intro/elim/dest
  1101 attributes; useful for building new logics, but beware of confusion
  1102 with the version in Provers/classical;
  1103 
  1104 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1105 case name 'antecedent';
  1106 
  1107 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1108 to the current context is now done automatically);
  1109 
  1110 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1111 for definining proof methods in ML;
  1112 
  1113 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1114 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1115 most cases, one should have to change intro!! to intro? only);
  1116 replaced "delrule" by "rule del";
  1117 
  1118 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1119 'symmetric' attribute (the latter supercedes [RS sym]);
  1120 
  1121 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1122 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1123 well (including splits);
  1124 
  1125 * Isar/Provers: Simplifier and Classical methods now support all kind
  1126 of modifiers used in the past, including 'cong', 'iff', etc.
  1127 
  1128 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1129 of Simplifier and Classical reasoner);
  1130 
  1131 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1132 now support named cases; major packages (inductive, datatype, primrec,
  1133 recdef) support case names and properly name parameters;
  1134 
  1135 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1136 monotonicity conditions are extracted to be proven at end of
  1137 calculations;
  1138 
  1139 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1140 method anyway;
  1141 
  1142 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1143 split_if split_if_asm; datatype package provides theorems foo.splits =
  1144 foo.split foo.split_asm for each datatype;
  1145 
  1146 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1147 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1148 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1149 use "(cases (simplified))" method in proper proof texts);
  1150 
  1151 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1152 
  1153 * Isar: names of theorems etc. may be natural numbers as well;
  1154 
  1155 * Isar: 'pr' command: optional arguments for goals_limit and
  1156 ProofContext.prems_limit; no longer prints theory contexts, but only
  1157 proof states;
  1158 
  1159 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1160 additional print modes to be specified; e.g. "pr(latex)" will print
  1161 proof state according to the Isabelle LaTeX style;
  1162 
  1163 * Isar: improved support for emulating tactic scripts, including proof
  1164 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1165 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1166 (for HOL datatypes);
  1167 
  1168 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1169 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1170 'proof method scripts' have to be in depth-first order;
  1171 
  1172 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1173 
  1174 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1175 should instead use individual commands for printing items
  1176 (print_commands, print_methods etc.);
  1177 
  1178 * Isar: added 'nothing' --- the empty list of theorems;
  1179 
  1180 
  1181 *** HOL ***
  1182 
  1183 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1184 corresponding virtual machine and a specification of its bytecode
  1185 verifier and a lightweight bytecode verifier, including proofs of
  1186 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1187 Cornelia Pusch (see also the homepage of project Bali at
  1188 http://isabelle.in.tum.de/Bali/);
  1189 
  1190 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1191 Clemens Ballarin;
  1192 
  1193 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1194 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1195 Rasmussen;
  1196 
  1197 * HOL/Lattice: fundamental concepts of lattice theory and order
  1198 structures, including duals, properties of bounds versus algebraic
  1199 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1200 Theorem for complete lattices etc.; may also serve as a demonstration
  1201 for abstract algebraic reasoning using axiomatic type classes, and
  1202 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1203 
  1204 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1205 von Oheimb;
  1206 
  1207 * HOL/IMPP: extension of IMP with local variables and mutually
  1208 recursive procedures, by David von Oheimb;
  1209 
  1210 * HOL/Lambda: converted into new-style theory and document;
  1211 
  1212 * HOL/ex/Multiquote: example of multiple nested quotations and
  1213 anti-quotations -- basically a generalized version of de-Bruijn
  1214 representation; very useful in avoiding lifting of operations;
  1215 
  1216 * HOL/record: added general record equality rule to simpset; fixed
  1217 select-update simplification procedure to handle extended records as
  1218 well; admit "r" as field name;
  1219 
  1220 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1221 other numeric types and also as the identity of groups, rings, etc.;
  1222 
  1223 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1224 Types nat and int belong to this axclass;
  1225 
  1226 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1227    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1228    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1229   two terms #m*u and #n*u are replaced by #(m+n)*u
  1230     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1231   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1232     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1233 
  1234 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1235 powerful prover for predicate logic but knows nothing of clasets; see
  1236 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1237 
  1238 * HOL: new version of "case_tac" subsumes both boolean case split and
  1239 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1240 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1241 
  1242 * HOL: simplification no longer dives into case-expressions: only the
  1243 selector expression is simplified, but not the remaining arms; to
  1244 enable full simplification of case-expressions for datatype t, you may
  1245 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1246 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1247 
  1248 * HOL/recdef: the recursion equations generated by 'recdef' for
  1249 function 'f' are now called f.simps instead of f.rules; if all
  1250 termination conditions are proved automatically, these simplification
  1251 rules are added to the simpset, as in primrec; rules may be named
  1252 individually as well, resulting in a separate list of theorems for
  1253 each equation;
  1254 
  1255 * HOL/While is a new theory that provides a while-combinator. It
  1256 permits the definition of tail-recursive functions without the
  1257 provision of a termination measure. The latter is necessary once the
  1258 invariant proof rule for while is applied.
  1259 
  1260 * HOL: new (overloaded) notation for the set of elements below/above
  1261 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1262 
  1263 * HOL: theorems impI, allI, ballI bound as "strip";
  1264 
  1265 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1266 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1267 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1268 
  1269 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1270 
  1271 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1272 main HOL, but was unused);
  1273 
  1274 * HOL: fewer consts declared as global (e.g. have to refer to
  1275 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1276 
  1277 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1278 in case of overlap with user translations (e.g. judgements over
  1279 tuples); (note that the underlying logical represenation is still
  1280 bogus);
  1281 
  1282 
  1283 *** ZF ***
  1284 
  1285 * ZF: simplification automatically cancels common terms in arithmetic
  1286 expressions over nat and int;
  1287 
  1288 * ZF: new treatment of nat to minimize type-checking: all operators
  1289 coerce their operands to a natural number using the function natify,
  1290 making the algebraic laws unconditional;
  1291 
  1292 * ZF: as above, for int: operators coerce their operands to an integer
  1293 using the function intify;
  1294 
  1295 * ZF: the integer library now contains many of the usual laws for the
  1296 orderings, including $<=, and monotonicity laws for $+ and $*;
  1297 
  1298 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1299 simplification;
  1300 
  1301 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1302 to the simplifier and classical reasoner simultaneously;
  1303 
  1304 
  1305 *** General ***
  1306 
  1307 * Provers: blast_tac now handles actual object-logic rules as
  1308 assumptions; note that auto_tac uses blast_tac internally as well;
  1309 
  1310 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1311 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1312 
  1313 * Provers: delrules now handles destruct rules as well (no longer need
  1314 explicit make_elim);
  1315 
  1316 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1317   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1318 use instead the strong form,
  1319   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1320 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1321 from destruct-rules;
  1322 
  1323 * Provers: Simplifier.easy_setup provides a fast path to basic
  1324 Simplifier setup for new object-logics;
  1325 
  1326 * Pure: AST translation rules no longer require constant head on LHS;
  1327 
  1328 * Pure: improved name spaces: ambiguous output is qualified; support
  1329 for hiding of names;
  1330 
  1331 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1332 XSYMBOL_HOME; no longer need to do manual configuration in most
  1333 situations;
  1334 
  1335 * system: compression of ML heaps images may now be controlled via -c
  1336 option of isabelle and isatool usedir (currently only observed by
  1337 Poly/ML);
  1338 
  1339 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1340 useful for remote X11);
  1341 
  1342 * system: provide TAGS file for Isabelle sources;
  1343 
  1344 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1345 order;
  1346 
  1347 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1348 timing flag supersedes proof_timing and Toplevel.trace;
  1349 
  1350 * ML: new combinators |>> and |>>> for incremental transformations
  1351 with secondary results (e.g. certain theory extensions):
  1352 
  1353 * ML: PureThy.add_defs gets additional argument to indicate potential
  1354 overloading (usually false);
  1355 
  1356 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1357 results;
  1358 
  1359 
  1360 
  1361 New in Isabelle99 (October 1999)
  1362 --------------------------------
  1363 
  1364 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1365 
  1366 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1367 are no longer simplified.  (This allows the simplifier to unfold recursive
  1368 functional programs.)  To restore the old behaviour, declare
  1369 
  1370     Delcongs [if_weak_cong];
  1371 
  1372 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1373 complement;
  1374 
  1375 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1376 
  1377 * HOL/datatype: mutual_induct_tac no longer exists --
  1378   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1379 
  1380 * HOL/typedef: fixed type inference for representing set; type
  1381 arguments now have to occur explicitly on the rhs as type constraints;
  1382 
  1383 * ZF: The con_defs part of an inductive definition may no longer refer
  1384 to constants declared in the same theory;
  1385 
  1386 * HOL, ZF: the function mk_cases, generated by the inductive
  1387 definition package, has lost an argument.  To simplify its result, it
  1388 uses the default simpset instead of a supplied list of theorems.
  1389 
  1390 * HOL/List: the constructors of type list are now Nil and Cons;
  1391 
  1392 * Simplifier: the type of the infix ML functions
  1393         setSSolver addSSolver setSolver addSolver
  1394 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1395 for packaging solvers. A solver is created via
  1396         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1397 where the string argument is only a comment.
  1398 
  1399 
  1400 *** Proof tools ***
  1401 
  1402 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1403 decision procedure for linear arithmetic. Currently it is used for
  1404 types `nat', `int', and `real' in HOL (see below); it can, should and
  1405 will be instantiated for other types and logics as well.
  1406 
  1407 * The simplifier now accepts rewrite rules with flexible heads, eg
  1408      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1409   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1410   matching.
  1411 
  1412 
  1413 *** General ***
  1414 
  1415 * New Isabelle/Isar subsystem provides an alternative to traditional
  1416 tactical theorem proving; together with the ProofGeneral/isar user
  1417 interface it offers an interactive environment for developing human
  1418 readable proof documents (Isar == Intelligible semi-automated
  1419 reasoning); for further information see isatool doc isar-ref,
  1420 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1421 
  1422 * improved and simplified presentation of theories: better HTML markup
  1423 (including colors), graph views in several sizes; isatool usedir now
  1424 provides a proper interface for user theories (via -P option); actual
  1425 document preparation based on (PDF)LaTeX is available as well (for
  1426 new-style theories only); see isatool doc system for more information;
  1427 
  1428 * native support for Proof General, both for classic Isabelle and
  1429 Isabelle/Isar;
  1430 
  1431 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1432 using the graph browser tool;
  1433 
  1434 * Isabelle manuals now also available as PDF;
  1435 
  1436 * theory loader rewritten from scratch (may not be fully
  1437 bug-compatible); old loadpath variable has been replaced by show_path,
  1438 add_path, del_path, reset_path functions; new operations such as
  1439 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1440 isatool doc ref);
  1441 
  1442 * improved isatool install: option -k creates KDE application icon,
  1443 option -p DIR installs standalone binaries;
  1444 
  1445 * added ML_PLATFORM setting (useful for cross-platform installations);
  1446 more robust handling of platform specific ML images for SML/NJ;
  1447 
  1448 * the settings environment is now statically scoped, i.e. it is never
  1449 created again in sub-processes invoked from isabelle, isatool, or
  1450 Isabelle;
  1451 
  1452 * path element specification '~~' refers to '$ISABELLE_HOME';
  1453 
  1454 * in locales, the "assumes" and "defines" parts may be omitted if
  1455 empty;
  1456 
  1457 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1458 long arrows);
  1459 
  1460 * new print_mode "HTML";
  1461 
  1462 * new flag show_tags controls display of tags of theorems (which are
  1463 basically just comments that may be attached by some tools);
  1464 
  1465 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1466 mode and goal output format:
  1467 
  1468 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1469 244c244
  1470 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1471 ---
  1472 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1473 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1474 181c181
  1475 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1476 ---
  1477 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1478 
  1479 * function bind_thms stores lists of theorems (cf. bind_thm);
  1480 
  1481 * new shorthand tactics ftac, eatac, datac, fatac;
  1482 
  1483 * qed (and friends) now accept "" as result name; in that case the
  1484 theorem is not stored, but proper checks and presentation of the
  1485 result still apply;
  1486 
  1487 * theorem database now also indexes constants "Trueprop", "all",
  1488 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1489 
  1490 
  1491 *** HOL ***
  1492 
  1493 ** HOL arithmetic **
  1494 
  1495 * There are now decision procedures for linear arithmetic over nat and
  1496 int:
  1497 
  1498 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1499 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1500 are treated as atomic; subformulae not involving type `nat' or `int'
  1501 are ignored; quantified subformulae are ignored unless they are
  1502 positive universal or negative existential. The tactic has to be
  1503 invoked by hand and can be a little bit slow. In particular, the
  1504 running time is exponential in the number of occurrences of `min' and
  1505 `max', and `-' on `nat'.
  1506 
  1507 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1508 (negated) (in)equalities among the premises and the conclusion into
  1509 account (i.e. no compound formulae) and does not know about `min' and
  1510 `max', and `-' on `nat'. It is fast and is used automatically by the
  1511 simplifier.
  1512 
  1513 NB: At the moment, these decision procedures do not cope with mixed
  1514 nat/int formulae where the two parts interact, such as `m < n ==>
  1515 int(m) < int(n)'.
  1516 
  1517 * HOL/Numeral provides a generic theory of numerals (encoded
  1518 efficiently as bit strings); setup for types nat/int/real is in place;
  1519 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1520 int, existing theories and proof scripts may require a few additional
  1521 type constraints;
  1522 
  1523 * integer division and remainder can now be performed on constant
  1524 arguments;
  1525 
  1526 * many properties of integer multiplication, division and remainder
  1527 are now available;
  1528 
  1529 * An interface to the Stanford Validity Checker (SVC) is available through the
  1530 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1531 are proved automatically.  SVC must be installed separately, and its results
  1532 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1533 invocation of the underlying oracle).  For SVC see
  1534   http://verify.stanford.edu/SVC
  1535 
  1536 * IsaMakefile: the HOL-Real target now builds an actual image;
  1537 
  1538 
  1539 ** HOL misc **
  1540 
  1541 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1542 (in Isabelle/Isar) -- by Gertrud Bauer;
  1543 
  1544 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1545 analysis for assembly languages with subtypes;
  1546 
  1547 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1548 -- avoids syntactic ambiguities and treats state, transition, and
  1549 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1550 changed syntax and (many) tactics;
  1551 
  1552 * HOL/inductive: Now also handles more general introduction rules such
  1553   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1554   theorems are now maintained within the theory (maintained via the
  1555   "mono" attribute);
  1556 
  1557 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1558   (using function types) such as
  1559 
  1560   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1561 
  1562 * HOL/record: record_simproc (part of the default simpset) takes care
  1563 of selectors applied to updated records; record_split_tac is no longer
  1564 part of the default claset; update_defs may now be removed from the
  1565 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1566 
  1567   claset_ref () := claset() addSWrapper record_split_wrapper;
  1568   Delsimprocs [record_simproc]
  1569 
  1570 * HOL/typedef: fixed type inference for representing set; type
  1571 arguments now have to occur explicitly on the rhs as type constraints;
  1572 
  1573 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1574 names rather than an ML expression;
  1575 
  1576 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1577 supplied later.  Program schemes can be defined, such as
  1578     "While B C s = (if B s then While B C (C s) else s)"
  1579 where the well-founded relation can be chosen after B and C have been given.
  1580 
  1581 * HOL/List: the constructors of type list are now Nil and Cons;
  1582 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1583 course, ML tools referring to List.list.op # etc. have to be adapted;
  1584 
  1585 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1586 disabled by default; run isabelle with option -m HOL to get back to
  1587 the original Gordon/HOL-style output;
  1588 
  1589 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1590 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1591 
  1592 * HOL basic syntax simplified (more orthogonal): all variants of
  1593 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1594 Eps operator is provided as well: "SOME x. P[x]";
  1595 
  1596 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1597 
  1598 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1599 thus available for user theories;
  1600 
  1601 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1602 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1603 time;
  1604 
  1605 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1606 several times and then mp;
  1607 
  1608 
  1609 *** LK ***
  1610 
  1611 * the notation <<...>> is now available as a notation for sequences of
  1612 formulas;
  1613 
  1614 * the simplifier is now installed
  1615 
  1616 * the axiom system has been generalized (thanks to Soren Heilmann)
  1617 
  1618 * the classical reasoner now has a default rule database
  1619 
  1620 
  1621 *** ZF ***
  1622 
  1623 * new primrec section allows primitive recursive functions to be given
  1624 directly (as in HOL) over datatypes and the natural numbers;
  1625 
  1626 * new tactics induct_tac and exhaust_tac for induction (or case
  1627 analysis) over datatypes and the natural numbers;
  1628 
  1629 * the datatype declaration of type T now defines the recursor T_rec;
  1630 
  1631 * simplification automatically does freeness reasoning for datatype
  1632 constructors;
  1633 
  1634 * automatic type-inference, with AddTCs command to insert new
  1635 type-checking rules;
  1636 
  1637 * datatype introduction rules are now added as Safe Introduction rules
  1638 to the claset;
  1639 
  1640 * the syntax "if P then x else y" is now available in addition to
  1641 if(P,x,y);
  1642 
  1643 
  1644 *** Internal programming interfaces ***
  1645 
  1646 * tuned simplifier trace output; new flag debug_simp;
  1647 
  1648 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1649 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1650 
  1651 * AxClass.axclass_tac lost the theory argument;
  1652 
  1653 * tuned current_goals_markers semantics: begin / end goal avoids
  1654 printing empty lines;
  1655 
  1656 * removed prs and prs_fn hook, which was broken because it did not
  1657 include \n in its semantics, forcing writeln to add one
  1658 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1659 string -> unit if you really want to output text without newline;
  1660 
  1661 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1662 plain output, interface builders may have to enable 'isabelle_font'
  1663 mode to get Isabelle font glyphs as before;
  1664 
  1665 * refined token_translation interface; INCOMPATIBILITY: output length
  1666 now of type real instead of int;
  1667 
  1668 * theory loader actions may be traced via new ThyInfo.add_hook
  1669 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1670 your own database of information attached to *whole* theories -- as
  1671 opposed to intra-theory data slots offered via TheoryDataFun;
  1672 
  1673 * proper handling of dangling sort hypotheses (at last!);
  1674 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1675 extra sort hypotheses that can be witnessed from the type signature;
  1676 the force_strip_shyps flag is gone, any remaining shyps are simply
  1677 left in the theorem (with a warning issued by strip_shyps_warning);
  1678 
  1679 
  1680 
  1681 New in Isabelle98-1 (October 1998)
  1682 ----------------------------------
  1683 
  1684 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1685 
  1686 * several changes of automated proof tools;
  1687 
  1688 * HOL: major changes to the inductive and datatype packages, including
  1689 some minor incompatibilities of theory syntax;
  1690 
  1691 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1692 called `inj_on';
  1693 
  1694 * HOL: removed duplicate thms in Arith:
  1695   less_imp_add_less  should be replaced by  trans_less_add1
  1696   le_imp_add_le      should be replaced by  trans_le_add1
  1697 
  1698 * HOL: unary minus is now overloaded (new type constraints may be
  1699 required);
  1700 
  1701 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1702 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1703 now taken as an integer constant.
  1704 
  1705 * Pure: ML function 'theory_of' renamed to 'theory';
  1706 
  1707 
  1708 *** Proof tools ***
  1709 
  1710 * Simplifier:
  1711   1. Asm_full_simp_tac is now more aggressive.
  1712      1. It will sometimes reorient premises if that increases their power to
  1713         simplify.
  1714      2. It does no longer proceed strictly from left to right but may also
  1715         rotate premises to achieve further simplification.
  1716      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1717      old Asm_full_simp_tac in that it does not rotate premises.
  1718   2. The simplifier now knows a little bit about nat-arithmetic.
  1719 
  1720 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1721 allows for selected deletion of wrappers, by introduction of names for
  1722 wrapper functionals.  This implies that addbefore, addSbefore,
  1723 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1724 and that adding two tactics with the same name overwrites the first
  1725 one (emitting a warning).
  1726   type wrapper = (int -> tactic) -> (int -> tactic)
  1727   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1728   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1729   delWrapper, delSWrapper: claset *  string            -> claset
  1730   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1731 
  1732 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1733 semantics; addbefore now affects only the unsafe part of step_tac
  1734 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1735 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1736 by Force_tac;
  1737 
  1738 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1739 compWrapper; added safe wrapper (and access functions for it);
  1740 
  1741 * HOL/split_all_tac is now much faster and fails if there is nothing
  1742 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1743 and the names of the automatically generated variables have changed.
  1744 split_all_tac has moved within claset() from unsafe wrappers to safe
  1745 wrappers, which means that !!-bound variables are split much more
  1746 aggressively, and safe_tac and clarify_tac now split such variables.
  1747 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1748 Note: the same holds for record_split_tac, which does the job of
  1749 split_all_tac for record fields.
  1750 
  1751 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1752 permanently to the default simpset using Addsplits just like
  1753 Addsimps. They can be removed via Delsplits just like
  1754 Delsimps. Lower-case versions are also available.
  1755 
  1756 * HOL/Simplifier: The rule split_if is now part of the default
  1757 simpset. This means that the simplifier will eliminate all occurrences
  1758 of if-then-else in the conclusion of a goal. To prevent this, you can
  1759 either remove split_if completely from the default simpset by
  1760 `Delsplits [split_if]' or remove it in a specific call of the
  1761 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1762 other case splitting rules to/from the default simpset: every datatype
  1763 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1764 t is the name of the datatype).
  1765 
  1766 * Classical reasoner / Simplifier combination: new force_tac (and
  1767 derivatives Force_tac, force) combines rewriting and classical
  1768 reasoning (and whatever other tools) similarly to auto_tac, but is
  1769 aimed to solve the given subgoal completely.
  1770 
  1771 
  1772 *** General ***
  1773 
  1774 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1775 and `goalw': the theory is no longer needed as an explicit argument -
  1776 the current theory context is used; assumptions are no longer returned
  1777 at the ML-level unless one of them starts with ==> or !!; it is
  1778 recommended to convert to these new commands using isatool fixgoal
  1779 (backup your sources first!);
  1780 
  1781 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1782 the current theory context, and 'theory' to lookup stored theories;
  1783 
  1784 * new theory section 'locale' for declaring constants, assumptions and
  1785 definitions that have local scope;
  1786 
  1787 * new theory section 'nonterminals' for purely syntactic types;
  1788 
  1789 * new theory section 'setup' for generic ML setup functions
  1790 (e.g. package initialization);
  1791 
  1792 * the distribution now includes Isabelle icons: see
  1793 lib/logo/isabelle-{small,tiny}.xpm;
  1794 
  1795 * isatool install - install binaries with absolute references to
  1796 ISABELLE_HOME/bin;
  1797 
  1798 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1799 
  1800 * print mode 'emacs' reserved for Isamode;
  1801 
  1802 * support multiple print (ast) translations per constant name;
  1803 
  1804 * theorems involving oracles are now printed with a suffixed [!];
  1805 
  1806 
  1807 *** HOL ***
  1808 
  1809 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1810 
  1811 * HOL/inductive package reorganized and improved: now supports mutual
  1812 definitions such as
  1813 
  1814   inductive EVEN ODD
  1815     intrs
  1816       null "0 : EVEN"
  1817       oddI "n : EVEN ==> Suc n : ODD"
  1818       evenI "n : ODD ==> Suc n : EVEN"
  1819 
  1820 new theorem list "elims" contains an elimination rule for each of the
  1821 recursive sets; inductive definitions now handle disjunctive premises
  1822 correctly (also ZF);
  1823 
  1824 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1825 "mutual_induct" no longer exists - the induction rule is always
  1826 contained in "induct";
  1827 
  1828 
  1829 * HOL/datatype package re-implemented and greatly improved: now
  1830 supports mutually recursive datatypes such as
  1831 
  1832   datatype
  1833     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1834             | SUM ('a aexp) ('a aexp)
  1835             | DIFF ('a aexp) ('a aexp)
  1836             | NUM 'a
  1837   and
  1838     'a bexp = LESS ('a aexp) ('a aexp)
  1839             | AND ('a bexp) ('a bexp)
  1840             | OR ('a bexp) ('a bexp)
  1841 
  1842 as well as indirectly recursive datatypes such as
  1843 
  1844   datatype
  1845     ('a, 'b) term = Var 'a
  1846                   | App 'b ((('a, 'b) term) list)
  1847 
  1848 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1849 induction on mutually / indirectly recursive datatypes.
  1850 
  1851 Primrec equations are now stored in theory and can be accessed via
  1852 <function_name>.simps.
  1853 
  1854 INCOMPATIBILITIES:
  1855 
  1856   - Theories using datatypes must now have theory Datatype as an
  1857     ancestor.
  1858   - The specific <typename>.induct_tac no longer exists - use the
  1859     generic induct_tac instead.
  1860   - natE has been renamed to nat.exhaust - use exhaust_tac
  1861     instead of res_inst_tac ... natE. Note that the variable
  1862     names in nat.exhaust differ from the names in natE, this
  1863     may cause some "fragile" proofs to fail.
  1864   - The theorems split_<typename>_case and split_<typename>_case_asm
  1865     have been renamed to <typename>.split and <typename>.split_asm.
  1866   - Since default sorts of type variables are now handled correctly,
  1867     some datatype definitions may have to be annotated with explicit
  1868     sort constraints.
  1869   - Primrec definitions no longer require function name and type
  1870     of recursive argument.
  1871 
  1872 Consider using isatool fixdatatype to adapt your theories and proof
  1873 scripts to the new package (backup your sources first!).
  1874 
  1875 
  1876 * HOL/record package: considerably improved implementation; now
  1877 includes concrete syntax for record types, terms, updates; theorems
  1878 for surjective pairing and splitting !!-bound record variables; proof
  1879 support is as follows:
  1880 
  1881   1) standard conversions (selectors or updates applied to record
  1882 constructor terms) are part of the standard simpset;
  1883 
  1884   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1885 made part of standard simpset and claset via addIffs;
  1886 
  1887   3) a tactic for record field splitting (record_split_tac) is part of
  1888 the standard claset (addSWrapper);
  1889 
  1890 To get a better idea about these rules you may retrieve them via
  1891 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1892 the name of your record type.
  1893 
  1894 The split tactic 3) conceptually simplifies by the following rule:
  1895 
  1896   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1897 
  1898 Thus any record variable that is bound by meta-all will automatically
  1899 blow up into some record constructor term, consequently the
  1900 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1901 solve record problems automatically.
  1902 
  1903 
  1904 * reorganized the main HOL image: HOL/Integ and String loaded by
  1905 default; theory Main includes everything;
  1906 
  1907 * automatic simplification of integer sums and comparisons, using cancellation;
  1908 
  1909 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1910 
  1911 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1912 
  1913 * many new identities for unions, intersections, set difference, etc.;
  1914 
  1915 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1916 called split_if, split_split, split_sum_case and split_nat_case (to go
  1917 with add/delsplits);
  1918 
  1919 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1920 (?x::unit) = (); this is made part of the default simpset, which COULD
  1921 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1922 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1923 unit_abs_eta_conv is added in order to counter the effect of
  1924 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1925 %u.f();
  1926 
  1927 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1928 makes more sense);
  1929 
  1930 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1931   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1932   disjointness reasoning but breaking a few old proofs.
  1933 
  1934 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1935 to 'converse' from 'inverse' (for compatibility with ZF and some
  1936 literature);
  1937 
  1938 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1939 the well-founded relation;
  1940 
  1941 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1942     Compl A.  The "Compl" syntax remains available as input syntax for this
  1943     release ONLY.
  1944 
  1945 * HOL/Update: new theory of function updates:
  1946     f(a:=b) == %x. if x=a then b else f x
  1947 may also be iterated as in f(a:=b,c:=d,...);
  1948 
  1949 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1950 
  1951 * HOL/List:
  1952   - new function list_update written xs[i:=v] that updates the i-th
  1953     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1954   - new function `upt' written [i..j(] which generates the list
  1955     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1956     bound write [i..j], which is a shorthand for [i..j+1(].
  1957   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1958 
  1959 * HOL/Arith:
  1960   - removed 'pred' (predecessor) function;
  1961   - generalized some theorems about n-1;
  1962   - many new laws about "div" and "mod";
  1963   - new laws about greatest common divisors (see theory ex/Primes);
  1964 
  1965 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1966 instead of "inverse";
  1967 
  1968 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1969   of the multiset ordering;
  1970 
  1971 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1972   (not included by default);
  1973 
  1974 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1975 
  1976 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1977   programs, i.e. different program variables may have different types.
  1978 
  1979 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1980   [previously, this check worked only if the rewrite rule was unconditional]
  1981   Now rew can involve either definitions or equalities (either == or =).
  1982 
  1983 
  1984 *** ZF ***
  1985 
  1986 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1987   only the theorems proved on ZF.ML;
  1988 
  1989 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1990   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1991   disjointness reasoning but breaking a few old proofs.
  1992 
  1993 * ZF/Update: new theory of function updates
  1994     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1995   may also be iterated as in f(a:=b,c:=d,...);
  1996 
  1997 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1998 
  1999 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2000   [previously, this check worked only if the rewrite rule was unconditional]
  2001   Now rew can involve either definitions or equalities (either == or =).
  2002 
  2003 * case_tac provided for compatibility with HOL
  2004     (like the old excluded_middle_tac, but with subgoals swapped)
  2005 
  2006 
  2007 *** Internal programming interfaces ***
  2008 
  2009 * Pure: several new basic modules made available for general use, see
  2010 also src/Pure/README;
  2011 
  2012 * improved the theory data mechanism to support encapsulation (data
  2013 kind name replaced by private Object.kind, acting as authorization
  2014 key); new type-safe user interface via functor TheoryDataFun; generic
  2015 print_data function becomes basically useless;
  2016 
  2017 * removed global_names compatibility flag -- all theory declarations
  2018 are qualified by default;
  2019 
  2020 * module Pure/Syntax now offers quote / antiquote translation
  2021 functions (useful for Hoare logic etc. with implicit dependencies);
  2022 see HOL/ex/Antiquote for an example use;
  2023 
  2024 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2025 cterm -> thm;
  2026 
  2027 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2028 subgoal;
  2029 
  2030 * Display.print_goals function moved to Locale.print_goals;
  2031 
  2032 * standard print function for goals supports current_goals_markers
  2033 variable for marking begin of proof, end of proof, start of goal; the
  2034 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2035 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2036 for example;
  2037 
  2038 
  2039 
  2040 New in Isabelle98 (January 1998)
  2041 --------------------------------
  2042 
  2043 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2044 
  2045 * changed lexical syntax of terms / types: dots made part of long
  2046 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2047 
  2048 * simpset (and claset) reference variable replaced by functions
  2049 simpset / simpset_ref;
  2050 
  2051 * no longer supports theory aliases (via merge) and non-trivial
  2052 implicit merge of thms' signatures;
  2053 
  2054 * most internal names of constants changed due to qualified names;
  2055 
  2056 * changed Pure/Sequence interface (see Pure/seq.ML);
  2057 
  2058 
  2059 *** General Changes ***
  2060 
  2061 * hierachically structured name spaces (for consts, types, axms, thms
  2062 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2063 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2064 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2065 long_names for fully qualified output names; NOTE: ML programs
  2066 (special tactics, packages etc.) referring to internal names may have
  2067 to be adapted to cope with fully qualified names; in case of severe
  2068 backward campatibility problems try setting 'global_names' at compile
  2069 time to have enrything declared within a flat name space; one may also
  2070 fine tune name declarations in theories via the 'global' and 'local'
  2071 section;
  2072 
  2073 * reimplemented the implicit simpset and claset using the new anytype
  2074 data filed in signatures; references simpset:simpset ref etc. are
  2075 replaced by functions simpset:unit->simpset and
  2076 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2077 to patch your ML files accordingly;
  2078 
  2079 * HTML output now includes theory graph data for display with Java
  2080 applet or isatool browser; data generated automatically via isatool
  2081 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2082 
  2083 * defs may now be conditional; improved rewrite_goals_tac to handle
  2084 conditional equations;
  2085 
  2086 * defs now admits additional type arguments, using TYPE('a) syntax;
  2087 
  2088 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2089 creates a new theory node; implicit merge of thms' signatures is
  2090 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2091 transfer:theory->thm->thm in (rare) cases;
  2092 
  2093 * improved handling of draft signatures / theories; draft thms (and
  2094 ctyps, cterms) are automatically promoted to real ones;
  2095 
  2096 * slightly changed interfaces for oracles: admit many per theory, named
  2097 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2098 
  2099 * print_goals: optional output of const types (set show_consts and
  2100 show_types);
  2101 
  2102 * improved output of warnings (###) and errors (***);
  2103 
  2104 * subgoal_tac displays a warning if the new subgoal has type variables;
  2105 
  2106 * removed old README and Makefiles;
  2107 
  2108 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2109 
  2110 * removed obsolete init_pps and init_database;
  2111 
  2112 * deleted the obsolete tactical STATE, which was declared by
  2113     fun STATE tacfun st = tacfun st st;
  2114 
  2115 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2116 (which abbreviates $HOME);
  2117 
  2118 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2119 use isatool fixseq to adapt your ML programs (this works for fully
  2120 qualified references to the Sequence structure only!);
  2121 
  2122 * use_thy no longer requires writable current directory; it always
  2123 reloads .ML *and* .thy file, if either one is out of date;
  2124 
  2125 
  2126 *** Classical Reasoner ***
  2127 
  2128 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2129 tactics that use classical reasoning to simplify a subgoal without
  2130 splitting it into several subgoals;
  2131 
  2132 * Safe_tac: like safe_tac but uses the default claset;
  2133 
  2134 
  2135 *** Simplifier ***
  2136 
  2137 * added simplification meta rules:
  2138     (asm_)(full_)simplify: simpset -> thm -> thm;
  2139 
  2140 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2141 logics (again);
  2142 
  2143 * added prems argument to simplification procedures;
  2144 
  2145 * HOL, FOL, ZF: added infix function `addsplits':
  2146   instead of `<simpset> setloop (split_tac <thms>)'
  2147   you can simply write `<simpset> addsplits <thms>'
  2148 
  2149 
  2150 *** Syntax ***
  2151 
  2152 * TYPE('a) syntax for type reflection terms;
  2153 
  2154 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2155 
  2156 * pretty printer: changed order of mixfix annotation preference (again!);
  2157 
  2158 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2159 
  2160 
  2161 *** HOL ***
  2162 
  2163 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2164   with `addloop' of the simplifier to faciliate case splitting in premises.
  2165 
  2166 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2167 
  2168 * HOL/Auth: new protocol proofs including some for the Internet
  2169   protocol TLS;
  2170 
  2171 * HOL/Map: new theory of `maps' a la VDM;
  2172 
  2173 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2174 cancelling out common nat summands from =, <, <= (in)equalities, or
  2175 differences; simplification procedures nat_cancel_factor for
  2176 cancelling common factor from =, <, <= (in)equalities over natural
  2177 sums; nat_cancel contains both kinds of procedures, it is installed by
  2178 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2179 
  2180 * HOL/simplifier: terms of the form
  2181   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2182   are rewritten to
  2183   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2184   and those of the form
  2185   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2186   are rewritten to
  2187   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2188 
  2189 * HOL/datatype
  2190   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2191 
  2192   P(t_case f1 ... fn x) =
  2193      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2194         ...
  2195        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2196      )
  2197 
  2198   and a theorem `split_t_case_asm' of the form
  2199 
  2200   P(t_case f1 ... fn x) =
  2201     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2202         ...
  2203        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2204      )
  2205   which can be added to a simpset via `addsplits'. The existing theorems
  2206   expand_list_case and expand_option_case have been renamed to
  2207   split_list_case and split_option_case.
  2208 
  2209 * HOL/Arithmetic:
  2210   - `pred n' is automatically converted to `n-1'.
  2211     Users are strongly encouraged not to use `pred' any longer,
  2212     because it will disappear altogether at some point.
  2213   - Users are strongly encouraged to write "0 < n" rather than
  2214     "n ~= 0". Theorems and proof tools have been modified towards this
  2215     `standard'.
  2216 
  2217 * HOL/Lists:
  2218   the function "set_of_list" has been renamed "set" (and its theorems too);
  2219   the function "nth" now takes its arguments in the reverse order and
  2220   has acquired the infix notation "!" as in "xs!n".
  2221 
  2222 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2223 
  2224 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2225   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2226 
  2227 * HOL/record: extensible records with schematic structural subtyping
  2228 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2229 still lacks various theorems and concrete record syntax;
  2230 
  2231 
  2232 *** HOLCF ***
  2233 
  2234 * removed "axioms" and "generated by" sections;
  2235 
  2236 * replaced "ops" section by extended "consts" section, which is capable of
  2237   handling the continuous function space "->" directly;
  2238 
  2239 * domain package:
  2240   . proves theorems immediately and stores them in the theory,
  2241   . creates hierachical name space,
  2242   . now uses normal mixfix annotations (instead of cinfix...),
  2243   . minor changes to some names and values (for consistency),
  2244   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2245   . separator between mutual domain defs: changed "," to "and",
  2246   . improved handling of sort constraints;  now they have to
  2247     appear on the left-hand side of the equations only;
  2248 
  2249 * fixed LAM <x,y,zs>.b syntax;
  2250 
  2251 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2252 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2253 
  2254 
  2255 *** FOL and ZF ***
  2256 
  2257 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2258   with `addloop' of the simplifier to faciliate case splitting in premises.
  2259 
  2260 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2261 in HOL, they strip ALL and --> from proved theorems;
  2262 
  2263 
  2264 
  2265 New in Isabelle94-8 (May 1997)
  2266 ------------------------------
  2267 
  2268 *** General Changes ***
  2269 
  2270 * new utilities to build / run / maintain Isabelle etc. (in parts
  2271 still somewhat experimental); old Makefiles etc. still functional;
  2272 
  2273 * new 'Isabelle System Manual';
  2274 
  2275 * INSTALL text, together with ./configure and ./build scripts;
  2276 
  2277 * reimplemented type inference for greater efficiency, better error
  2278 messages and clean internal interface;
  2279 
  2280 * prlim command for dealing with lots of subgoals (an easier way of
  2281 setting goals_limit);
  2282 
  2283 
  2284 *** Syntax ***
  2285 
  2286 * supports alternative (named) syntax tables (parser and pretty
  2287 printer); internal interface is provided by add_modesyntax(_i);
  2288 
  2289 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2290 be used in conjunction with the Isabelle symbol font; uses the
  2291 "symbols" syntax table;
  2292 
  2293 * added token_translation interface (may translate name tokens in
  2294 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2295 the current print_mode); IMPORTANT: user print translation functions
  2296 are responsible for marking newly introduced bounds
  2297 (Syntax.mark_boundT);
  2298 
  2299 * token translations for modes "xterm" and "xterm_color" that display
  2300 names in bold, underline etc. or colors (which requires a color
  2301 version of xterm);
  2302 
  2303 * infixes may now be declared with names independent of their syntax;
  2304 
  2305 * added typed_print_translation (like print_translation, but may
  2306 access type of constant);
  2307 
  2308 
  2309 *** Classical Reasoner ***
  2310 
  2311 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2312 some limitations.  Blast_tac...
  2313   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2314   + ignores elimination rules that don't have the correct format
  2315         (the conclusion MUST be a formula variable)
  2316   + ignores types, which can make HOL proofs fail
  2317   + rules must not require higher-order unification, e.g. apply_type in ZF
  2318     [message "Function Var's argument not a bound variable" relates to this]
  2319   + its proof strategy is more general but can actually be slower
  2320 
  2321 * substitution with equality assumptions no longer permutes other
  2322 assumptions;
  2323 
  2324 * minor changes in semantics of addafter (now called addaltern); renamed
  2325 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2326 (and access functions for it);
  2327 
  2328 * improved combination of classical reasoner and simplifier:
  2329   + functions for handling clasimpsets
  2330   + improvement of addss: now the simplifier is called _after_ the
  2331     safe steps.
  2332   + safe variant of addss called addSss: uses safe simplifications
  2333     _during_ the safe steps. It is more complete as it allows multiple
  2334     instantiations of unknowns (e.g. with slow_tac).
  2335 
  2336 *** Simplifier ***
  2337 
  2338 * added interface for simplification procedures (functions that
  2339 produce *proven* rewrite rules on the fly, depending on current
  2340 redex);
  2341 
  2342 * ordering on terms as parameter (used for ordered rewriting);
  2343 
  2344 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2345 
  2346 * the solver is now split into a safe and an unsafe part.
  2347 This should be invisible for the normal user, except that the
  2348 functions setsolver and addsolver have been renamed to setSolver and
  2349 addSolver; added safe_asm_full_simp_tac;
  2350 
  2351 
  2352 *** HOL ***
  2353 
  2354 * a generic induction tactic `induct_tac' which works for all datatypes and
  2355 also for type `nat';
  2356 
  2357 * a generic case distinction tactic `exhaust_tac' which works for all
  2358 datatypes and also for type `nat';
  2359 
  2360 * each datatype comes with a function `size';
  2361 
  2362 * patterns in case expressions allow tuple patterns as arguments to
  2363 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2364 
  2365 * primrec now also works with type nat;
  2366 
  2367 * recdef: a new declaration form, allows general recursive functions to be
  2368 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2369 
  2370 * the constant for negation has been renamed from "not" to "Not" to
  2371 harmonize with FOL, ZF, LK, etc.;
  2372 
  2373 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2374 infinite lists;
  2375 
  2376 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2377 
  2378 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2379 problems in commutative rings, using axiomatic type classes for + and *;
  2380 
  2381 * more examples in HOL/MiniML and HOL/Auth;
  2382 
  2383 * more default rewrite rules for quantifiers, union/intersection;
  2384 
  2385 * a new constant `arbitrary == @x.False';
  2386 
  2387 * HOLCF/IOA replaces old HOL/IOA;
  2388 
  2389 * HOLCF changes: derived all rules and arities
  2390   + axiomatic type classes instead of classes
  2391   + typedef instead of faking type definitions
  2392   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2393   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2394   + eliminated the types void, one, tr
  2395   + use unit lift and bool lift (with translations) instead of one and tr
  2396   + eliminated blift from Lift3.thy (use Def instead of blift)
  2397   all eliminated rules are derived as theorems --> no visible changes ;
  2398 
  2399 
  2400 *** ZF ***
  2401 
  2402 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2403 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2404 as ZF_cs addSIs [equalityI];
  2405 
  2406 
  2407 
  2408 New in Isabelle94-7 (November 96)
  2409 ---------------------------------
  2410 
  2411 * allowing negative levels (as offsets) in prlev and choplev;
  2412 
  2413 * super-linear speedup for large simplifications;
  2414 
  2415 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2416 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2417 FAIL); can suppress it using the command Delsimps (ex_simps @
  2418 all_simps); De Morgan laws are also now included, by default;
  2419 
  2420 * improved printing of ==>  :  ~:
  2421 
  2422 * new object-logic "Sequents" adds linear logic, while replacing LK
  2423 and Modal (thanks to Sara Kalvala);
  2424 
  2425 * HOL/Auth: correctness proofs for authentication protocols;
  2426 
  2427 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2428 examples on HOL/Auth);
  2429 
  2430 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2431 the rewriter and classical reasoner simultaneously;
  2432 
  2433 * function uresult no longer returns theorems in "standard" format;
  2434 regain previous version by: val uresult = standard o uresult;
  2435 
  2436 
  2437 
  2438 New in Isabelle94-6
  2439 -------------------
  2440 
  2441 * oracles -- these establish an interface between Isabelle and trusted
  2442 external reasoners, which may deliver results as theorems;
  2443 
  2444 * proof objects (in particular record all uses of oracles);
  2445 
  2446 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2447 
  2448 * "constdefs" section in theory files;
  2449 
  2450 * "primrec" section (HOL) no longer requires names;
  2451 
  2452 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2453 
  2454 
  2455 
  2456 New in Isabelle94-5
  2457 -------------------
  2458 
  2459 * reduced space requirements;
  2460 
  2461 * automatic HTML generation from theories;
  2462 
  2463 * theory files no longer require "..." (quotes) around most types;
  2464 
  2465 * new examples, including two proofs of the Church-Rosser theorem;
  2466 
  2467 * non-curried (1994) version of HOL is no longer distributed;
  2468 
  2469 
  2470 
  2471 New in Isabelle94-4
  2472 -------------------
  2473 
  2474 * greatly reduced space requirements;
  2475 
  2476 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2477 
  2478 * searchable theorem database (see the section "Retrieving theorems" on
  2479 page 8 of the Reference Manual);
  2480 
  2481 * new examples, including Grabczewski's monumental case study of the
  2482 Axiom of Choice;
  2483 
  2484 * The previous version of HOL renamed to Old_HOL;
  2485 
  2486 * The new version of HOL (previously called CHOL) uses a curried syntax
  2487 for functions.  Application looks like f a b instead of f(a,b);
  2488 
  2489 * Mutually recursive inductive definitions finally work in HOL;
  2490 
  2491 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2492 translates to the operator "split";
  2493 
  2494 
  2495 
  2496 New in Isabelle94-3
  2497 -------------------
  2498 
  2499 * new infix operator, addss, allowing the classical reasoner to
  2500 perform simplification at each step of its search.  Example:
  2501         fast_tac (cs addss ss)
  2502 
  2503 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2504 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2505 look like (a,b) instead of <a,b>;
  2506 
  2507 * PLEASE NOTE: CHOL will eventually replace HOL!
  2508 
  2509 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2510 It translates to the operator "split".  A new theory of integers is available;
  2511 
  2512 * In ZF, integer numerals now denote two's-complement binary integers.
  2513 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2514 
  2515 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2516 of the Axiom of Choice;
  2517 
  2518 
  2519 
  2520 New in Isabelle94-2
  2521 -------------------
  2522 
  2523 * Significantly faster resolution;
  2524 
  2525 * the different sections in a .thy file can now be mixed and repeated
  2526 freely;
  2527 
  2528 * Database of theorems for FOL, HOL and ZF.  New
  2529 commands including qed, qed_goal and bind_thm store theorems in the database.
  2530 
  2531 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2532 a given theory (thms_of), or find out what theory a theorem was proved in
  2533 (theory_of_thm);
  2534 
  2535 * Bugs fixed in the inductive definition and datatype packages;
  2536 
  2537 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2538 and HOL_dup_cs obsolete;
  2539 
  2540 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2541 have been removed;
  2542 
  2543 * Simpler definition of function space in ZF;
  2544 
  2545 * new results about cardinal and ordinal arithmetic in ZF;
  2546 
  2547 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2548 types;
  2549 
  2550 
  2551 $Id$