NEWS
author skalberg
Thu Aug 28 01:56:40 2003 +0200 (2003-08-28)
changeset 14171 0cab06e3bbd0
parent 14136 9b7a62788dac
child 14172 a872d646bf01
permissions -rw-r--r--
Extended the notion of letter and digit, such that now one may use greek,
gothic, euler, or calligraphic letters as normal letters.
     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
    11   euler (\<a>...\<z>), are now considered normal letters, and can
    12   therefore be used anywhere where an ASCII letter (a...zA...Z) has
    13   until now.  Similarily, the symbol digits \<0>...\<9> are now
    14   considered normal digits.  COMPATIBILITY: This obviously changes the
    15   parsing of some terms, especially where a symbol has been used as a
    16   binder, say '\<Pi>x. ...', which is now a type error since \<Pi>x
    17   will be parsed as an identifier.  Fix it by inserting a space around
    18   former symbols.  Call 'isatool fixgreek' to try to fix parsing
    19   errors in existing theory and ML files.
    20 
    21 *** HOL ***
    22 
    23 * 'specification' command added, allowing for definition by
    24 specification.
    25 
    26 
    27 New in Isabelle2003 (May 2003)
    28 --------------------------------
    29 
    30 *** General ***
    31 
    32 * Provers/simplifier:
    33 
    34   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
    35     Assumptions are now subject to complete mutual simplification,
    36     not just from left to right. The simplifier now preserves
    37     the order of assumptions.
    38 
    39     Potential INCOMPATIBILITY:
    40 
    41     -- simp sometimes diverges where the old version did
    42        not, e.g. invoking simp on the goal
    43 
    44         [| P (f x); y = x; f x = f y |] ==> Q
    45 
    46        now gives rise to the infinite reduction sequence
    47 
    48         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
    49 
    50        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
    51        kind of problem.
    52 
    53     -- Tactics combining classical reasoner and simplification (such as auto)
    54        are also affected by this change, because many of them rely on
    55        simp. They may sometimes diverge as well or yield a different numbers
    56        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
    57        in case of problems. Sometimes subsequent calls to the classical
    58        reasoner will fail because a preceeding call to the simplifier too
    59        eagerly simplified the goal, e.g. deleted redundant premises.
    60 
    61   - The simplifier trace now shows the names of the applied rewrite rules
    62 
    63   - You can limit the number of recursive invocations of the simplifier
    64     during conditional rewriting (where the simplifie tries to solve the
    65     conditions before applying the rewrite rule):
    66     ML "simp_depth_limit := n"
    67     where n is an integer. Thus you can force termination where previously
    68     the simplifier would diverge.
    69 
    70   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
    71 
    72   - No longer aborts on failed congruence proof.  Instead, the
    73     congruence is ignored.
    74 
    75 * Pure: New generic framework for extracting programs from constructive
    76   proofs. See HOL/Extraction.thy for an example instantiation, as well
    77   as HOL/Extraction for some case studies.
    78 
    79 * Pure: The main goal of the proof state is no longer shown by default, only
    80 the subgoals. This behaviour is controlled by a new flag.
    81    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
    82 (ML: Proof.show_main_goal).
    83 
    84 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
    85 rules whose conclusion matches subgoal 1:
    86       PG menu: Isabelle/Isar -> Show me -> matching rules
    87 The rules are ordered by how closely they match the subgoal.
    88 In particular, rules that solve a subgoal outright are displayed first
    89 (or rather last, the way they are printed).
    90 (ML: ProofGeneral.print_intros())
    91 
    92 * Pure: New flag trace_unify_fail causes unification to print
    93 diagnostic information (PG: in trace buffer) when it fails. This is
    94 useful for figuring out why single step proofs like rule, erule or
    95 assumption failed.
    96 
    97 * Pure: Locale specifications now produce predicate definitions
    98 according to the body of text (covering assumptions modulo local
    99 definitions); predicate "loc_axioms" covers newly introduced text,
   100 while "loc" is cumulative wrt. all included locale expressions; the
   101 latter view is presented only on export into the global theory
   102 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   103 on the old view without predicates;
   104 
   105 * Pure: predefined locales "var" and "struct" are useful for sharing
   106 parameters (as in CASL, for example); just specify something like
   107 ``var x + var y + struct M'' as import;
   108 
   109 * Pure: improved thms_containing: proper indexing of facts instead of
   110 raw theorems; check validity of results wrt. current name space;
   111 include local facts of proof configuration (also covers active
   112 locales), cover fixed variables in index; may use "_" in term
   113 specification; an optional limit for the number of printed facts may
   114 be given (the default is 40);
   115 
   116 * Pure: disallow duplicate fact bindings within new-style theory files
   117 (batch-mode only);
   118 
   119 * Provers: improved induct method: assumptions introduced by case
   120 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   121 the goal statement); "foo" still refers to all facts collectively;
   122 
   123 * Provers: the function blast.overloaded has been removed: all constants
   124 are regarded as potentially overloaded, which improves robustness in exchange
   125 for slight decrease in efficiency;
   126 
   127 * Provers/linorder: New generic prover for transitivity reasoning over
   128 linear orders.  Note: this prover is not efficient!
   129 
   130 * Isar: preview of problems to finish 'show' now produce an error
   131 rather than just a warning (in interactive mode);
   132 
   133 
   134 *** HOL ***
   135 
   136 * arith(_tac)
   137 
   138  - Produces a counter example if it cannot prove a goal.
   139    Note that the counter example may be spurious if the goal is not a formula
   140    of quantifier-free linear arithmetic.
   141    In ProofGeneral the counter example appears in the trace buffer.
   142 
   143  - Knows about div k and mod k where k is a numeral of type nat or int.
   144 
   145  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   146    linear arithmetic fails. This takes account of quantifiers and divisibility.
   147    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   148 
   149 * simp's arithmetic capabilities have been enhanced a bit: it now
   150 takes ~= in premises into account (by performing a case split);
   151 
   152 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   153 are distributed over a sum of terms;
   154 
   155 * New tactic "trans_tac" and method "trans" instantiate
   156 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   157 "<=", "<" and "="). 
   158 
   159 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   160 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   161 
   162 * 'typedef' command has new option "open" to suppress the set
   163 definition;
   164 
   165 * functions Min and Max on finite sets have been introduced (theory
   166 Finite_Set);
   167 
   168 * attribute [symmetric] now works for relations as well; it turns
   169 (x,y) : R^-1 into (y,x) : R, and vice versa;
   170 
   171 * induct over a !!-quantified statement (say !!x1..xn):
   172   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   173 
   174 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   175 %x. None. Warning: empty_def now refers to the previously hidden definition
   176 of the empty set.
   177 
   178 * Algebra: formalization of classical algebra.  Intended as base for
   179 any algebraic development in Isabelle.  Currently covers group theory
   180 (up to Sylow's theorem) and ring theory (Universal Property of
   181 Univariate Polynomials).  Contributions welcome;
   182 
   183 * GroupTheory: deleted, since its material has been moved to Algebra;
   184 
   185 * Complex: new directory of the complex numbers with numeric constants, 
   186 nonstandard complex numbers, and some complex analysis, standard and 
   187 nonstandard (Jacques Fleuriot);
   188 
   189 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   190 
   191 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   192 Fleuriot);
   193 
   194 * Real/HahnBanach: updated and adapted to locales;
   195 
   196 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   197 Gray and Kramer);
   198 
   199 * UNITY: added the Meier-Sanders theory of progress sets;
   200 
   201 * MicroJava: bytecode verifier and lightweight bytecode verifier
   202 as abstract algorithms, instantiated to the JVM;
   203 
   204 * Bali: Java source language formalization. Type system, operational
   205 semantics, axiomatic semantics. Supported language features:
   206 classes, interfaces, objects,virtual methods, static methods,
   207 static/instance fields, arrays, access modifiers, definite
   208 assignment, exceptions.
   209 
   210 
   211 *** ZF ***
   212 
   213 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   214 universe, etc.);
   215 
   216 * Main ZF: virtually all theories converted to new-style format;
   217 
   218 
   219 *** ML ***
   220 
   221 * Pure: Tactic.prove provides sane interface for internal proofs;
   222 omits the infamous "standard" operation, so this is more appropriate
   223 than prove_goalw_cterm in many situations (e.g. in simprocs);
   224 
   225 * Pure: improved error reporting of simprocs;
   226 
   227 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   228 up simprocs;
   229 
   230 
   231 *** Document preparation ***
   232 
   233 * uses \par instead of \\ for line breaks in theory text. This may
   234 shift some page breaks in large documents. To get the old behaviour
   235 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   236 
   237 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   238 other packages
   239 
   240 * \<euro> now needs package babel/greek instead of marvosym (which
   241 broke \Rightarrow)
   242 
   243 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   244 textcomp package)
   245 
   246 
   247 New in Isabelle2002 (March 2002)
   248 --------------------------------
   249 
   250 *** Document preparation ***
   251 
   252 * greatly simplified document preparation setup, including more
   253 graceful interpretation of isatool usedir -i/-d/-D options, and more
   254 instructive isatool mkdir; users should basically be able to get
   255 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   256 users may run a separate document processing stage manually like this:
   257 "isatool usedir -D output HOL Test && isatool document Test/output";
   258 
   259 * theory dependency graph may now be incorporated into documents;
   260 isatool usedir -g true will produce session_graph.eps/.pdf for use
   261 with \includegraphics of LaTeX;
   262 
   263 * proper spacing of consecutive markup elements, especially text
   264 blocks after section headings;
   265 
   266 * support bold style (for single symbols only), input syntax is like
   267 this: "\<^bold>\<alpha>" or "\<^bold>A";
   268 
   269 * \<bullet> is now output as bold \cdot by default, which looks much
   270 better in printed text;
   271 
   272 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   273 note that these symbols are currently unavailable in Proof General /
   274 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   275 
   276 * isatool latex no longer depends on changed TEXINPUTS, instead
   277 isatool document copies the Isabelle style files to the target
   278 location;
   279 
   280 
   281 *** Isar ***
   282 
   283 * Pure/Provers: improved proof by cases and induction;
   284   - 'case' command admits impromptu naming of parameters (such as
   285     "case (Suc n)");
   286   - 'induct' method divinates rule instantiation from the inductive
   287     claim; no longer requires excessive ?P bindings for proper
   288     instantiation of cases;
   289   - 'induct' method properly enumerates all possibilities of set/type
   290     rules; as a consequence facts may be also passed through *type*
   291     rules without further ado;
   292   - 'induct' method now derives symbolic cases from the *rulified*
   293     rule (before it used to rulify cases stemming from the internal
   294     atomized version); this means that the context of a non-atomic
   295     statement becomes is included in the hypothesis, avoiding the
   296     slightly cumbersome show "PROP ?case" form;
   297   - 'induct' may now use elim-style induction rules without chaining
   298     facts, using ``missing'' premises from the goal state; this allows
   299     rules stemming from inductive sets to be applied in unstructured
   300     scripts, while still benefitting from proper handling of non-atomic
   301     statements; NB: major inductive premises need to be put first, all
   302     the rest of the goal is passed through the induction;
   303   - 'induct' proper support for mutual induction involving non-atomic
   304     rule statements (uses the new concept of simultaneous goals, see
   305     below);
   306   - append all possible rule selections, but only use the first
   307     success (no backtracking);
   308   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   309   - undeclared rule case names default to numbers 1, 2, 3, ...;
   310   - added 'print_induct_rules' (covered by help item in recent Proof
   311     General versions);
   312   - moved induct/cases attributes to Pure, methods to Provers;
   313   - generic method setup instantiated for FOL and HOL;
   314 
   315 * Pure: support multiple simultaneous goal statements, for example
   316 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   317 meta-level mechanism, this acts as if several individual goals had
   318 been stated separately; in particular common proof methods need to be
   319 repeated in order to cover all claims; note that a single elimination
   320 step is *not* sufficient to establish the two conjunctions, so this
   321 fails:
   322 
   323   assume "A & B" then have A and B ..   (*".." fails*)
   324 
   325 better use "obtain" in situations as above; alternative refer to
   326 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   327 
   328 * Pure: proper integration with ``locales''; unlike the original
   329 version by Florian Kammüller, Isar locales package high-level proof
   330 contexts rather than raw logical ones (e.g. we admit to include
   331 attributes everywhere); operations on locales include merge and
   332 rename; support for implicit arguments (``structures''); simultaneous
   333 type-inference over imports and text; see also HOL/ex/Locales.thy for
   334 some examples;
   335 
   336 * Pure: the following commands have been ``localized'', supporting a
   337 target locale specification "(in name)": 'lemma', 'theorem',
   338 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   339 stored both within the locale and at the theory level (exported and
   340 qualified by the locale name);
   341 
   342 * Pure: theory goals may now be specified in ``long'' form, with
   343 ad-hoc contexts consisting of arbitrary locale elements. for example
   344 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   345 definitions may be given, too); the result is a meta-level rule with
   346 the context elements being discharged in the obvious way;
   347 
   348 * Pure: new proof command 'using' allows to augment currently used
   349 facts after a goal statement ('using' is syntactically analogous to
   350 'apply', but acts on the goal's facts only); this allows chained facts
   351 to be separated into parts given before and after a claim, as in
   352 ``from a and b have C using d and e <proof>'';
   353 
   354 * Pure: renamed "antecedent" case to "rule_context";
   355 
   356 * Pure: new 'judgment' command records explicit information about the
   357 object-logic embedding (used by several tools internally); no longer
   358 use hard-wired "Trueprop";
   359 
   360 * Pure: added 'corollary' command;
   361 
   362 * Pure: fixed 'token_translation' command;
   363 
   364 * Pure: removed obsolete 'exported' attribute;
   365 
   366 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   367 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   368 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   369 
   370 * Pure: method 'atomize' presents local goal premises as object-level
   371 statements (atomic meta-level propositions); setup controlled via
   372 rewrite rules declarations of 'atomize' attribute; example
   373 application: 'induct' method with proper rule statements in improper
   374 proof *scripts*;
   375 
   376 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   377 now consider the syntactic context of assumptions, giving a better
   378 chance to get type-inference of the arguments right (this is
   379 especially important for locales);
   380 
   381 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   382 mode;
   383 
   384 * Pure/obtain: the formal conclusion "thesis", being marked as
   385 ``internal'', may no longer be reference directly in the text;
   386 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   387 situations;
   388 
   389 * Pure: generic 'sym' attribute which declares a rule both as pure
   390 'elim?' and for the 'symmetric' operation;
   391 
   392 * Pure: marginal comments ``--'' may now occur just anywhere in the
   393 text; the fixed correlation with particular command syntax has been
   394 discontinued;
   395 
   396 * Pure: new method 'rules' is particularly well-suited for proof
   397 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   398 but often produces more compact proof terms with less detours;
   399 
   400 * Pure/Provers/classical: simplified integration with pure rule
   401 attributes and methods; the classical "intro?/elim?/dest?"
   402 declarations coincide with the pure ones; the "rule" method no longer
   403 includes classically swapped intros; "intro" and "elim" methods no
   404 longer pick rules from the context; also got rid of ML declarations
   405 AddXIs/AddXEs/AddXDs; all of this has some potential for
   406 INCOMPATIBILITY;
   407 
   408 * Provers/classical: attribute 'swapped' produces classical inversions
   409 of introduction rules;
   410 
   411 * Provers/simplifier: 'simplified' attribute may refer to explicit
   412 rules instead of full simplifier context; 'iff' attribute handles
   413 conditional rules;
   414 
   415 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   416 
   417 * HOL: 'recdef' now fails on unfinished automated proofs, use
   418 "(permissive)" option to recover old behavior;
   419 
   420 * HOL: 'inductive' no longer features separate (collective) attributes
   421 for 'intros' (was found too confusing);
   422 
   423 * HOL: properly declared induction rules less_induct and
   424 wf_induct_rule;
   425 
   426 
   427 *** HOL ***
   428 
   429 * HOL: moved over to sane numeral syntax; the new policy is as
   430 follows:
   431 
   432   - 0 and 1 are polymorphic constants, which are defined on any
   433   numeric type (nat, int, real etc.);
   434 
   435   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   436   binary representation internally;
   437 
   438   - type nat has special constructor Suc, and generally prefers Suc 0
   439   over 1::nat and Suc (Suc 0) over 2::nat;
   440 
   441 This change may cause significant problems of INCOMPATIBILITY; here
   442 are some hints on converting existing sources:
   443 
   444   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   445   entities, so expressions involving "-" (unary or binary minus) need
   446   to be spaced properly;
   447 
   448   - existing occurrences of "1" may need to be constraint "1::nat" or
   449   even replaced by Suc 0; similar for old "2";
   450 
   451   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   452 
   453   - remove all special provisions on numerals in proofs;
   454 
   455 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   456 representation (depends on bin_arith_simps in the default context);
   457 
   458 * HOL: symbolic syntax for x^2 (numeral 2);
   459 
   460 * HOL: the class of all HOL types is now called "type" rather than
   461 "term"; INCOMPATIBILITY, need to adapt references to this type class
   462 in axclass/classes, instance/arities, and (usually rare) occurrences
   463 in typings (of consts etc.); internally the class is called
   464 "HOL.type", ML programs should refer to HOLogic.typeS;
   465 
   466 * HOL/record package improvements:
   467   - new derived operations "fields" to build a partial record section,
   468     "extend" to promote a fixed record to a record scheme, and
   469     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   470     declared as simp by default;
   471   - shared operations ("more", "fields", etc.) now need to be always
   472     qualified) --- potential INCOMPATIBILITY;
   473   - removed "make_scheme" operations (use "make" with "extend") --
   474     INCOMPATIBILITY;
   475   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   476   - provides cases/induct rules for use with corresponding Isar
   477     methods (for concrete records, record schemes, concrete more
   478     parts, and schematic more parts -- in that order);
   479   - internal definitions directly based on a light-weight abstract
   480     theory of product types over typedef rather than datatype;
   481 
   482 * HOL: generic code generator for generating executable ML code from
   483 specifications; specific support for HOL constructs such as inductive
   484 datatypes and sets, as well as recursive functions; can be invoked
   485 via 'generate_code' theory section;
   486 
   487 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   488 
   489 * HOL: consolidated and renamed several theories.  In particular:
   490 	Ord.thy has been absorbed into HOL.thy
   491 	String.thy has been absorbed into List.thy
   492  
   493 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   494 (beware of argument permutation!);
   495 
   496 * HOL: linorder_less_split superseded by linorder_cases;
   497 
   498 * HOL/List: "nodups" renamed to "distinct";
   499 
   500 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   501 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   502   - Ex_def has changed, now need to use some_eq_ex
   503 
   504 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   505 in this (rare) case use:
   506 
   507   delSWrapper "split_all_tac"
   508   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   509 
   510 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   511 MAY FAIL;
   512 
   513 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   514 Isabelle's type classes, ^ on functions and relations has too general
   515 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   516 necessary to attach explicit type constraints;
   517 
   518 * HOL/Relation: the prefix name of the infix "O" has been changed from
   519 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   520 renamed accordingly (eg "compI" -> "rel_compI").
   521 
   522 * HOL: syntax translations now work properly with numerals and records
   523 expressions;
   524 
   525 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   526 of "lam" -- INCOMPATIBILITY;
   527 
   528 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   529 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   530 renamed "Product_Type.unit";
   531 
   532 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   533 
   534 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   535 the "cases" method);
   536 
   537 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   538 Florian Kammüller);
   539 
   540 * HOL/IMP: updated and converted to new-style theory format; several
   541 parts turned into readable document, with proper Isar proof texts and
   542 some explanations (by Gerwin Klein);
   543 
   544 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   545 
   546 * HOL-Hyperreal is now a logic image;
   547 
   548 
   549 *** HOLCF ***
   550 
   551 * Isar: consts/constdefs supports mixfix syntax for continuous
   552 operations;
   553 
   554 * Isar: domain package adapted to new-style theory format, e.g. see
   555 HOLCF/ex/Dnat.thy;
   556 
   557 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   558 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   559 lift.induct_tac, always use UU instead of Undef;
   560 
   561 * HOLCF/IMP: updated and converted to new-style theory;
   562 
   563 
   564 *** ZF ***
   565 
   566 * Isar: proper integration of logic-specific tools and packages,
   567 including theory commands '(co)inductive', '(co)datatype',
   568 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   569 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   570 
   571 * theory Main no longer includes AC; for the Axiom of Choice, base
   572 your theory on Main_ZFC;
   573 
   574 * the integer library now covers quotients and remainders, with many
   575 laws relating division to addition, multiplication, etc.;
   576 
   577 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   578 typeless version of the formalism;
   579 
   580 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   581 format;
   582 
   583 * ZF/Induct: new directory for examples of inductive definitions,
   584 including theory Multiset for multiset orderings; converted to
   585 new-style theory format;
   586 
   587 * ZF: many new theorems about lists, ordinals, etc.;
   588 
   589 
   590 *** General ***
   591 
   592 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   593 variable proof controls level of detail: 0 = no proofs (only oracle
   594 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   595 also ref manual for further ML interfaces;
   596 
   597 * Pure/axclass: removed obsolete ML interface
   598 goal_subclass/goal_arity;
   599 
   600 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   601 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   602 separate tokens, so expressions involving minus need to be spaced
   603 properly;
   604 
   605 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   606 rather than "infixl" or "infixr";
   607 
   608 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   609 sort constraint specifications in type inference; e.g. "x::_::foo"
   610 ensures that the type of "x" is of sort "foo" (but not necessarily a
   611 type variable);
   612 
   613 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   614 control output of nested => (types); the default behavior is
   615 "type_brackets";
   616 
   617 * Pure/syntax: builtin parse translation for "_constify" turns valued
   618 tokens into AST constants;
   619 
   620 * Pure/syntax: prefer later declarations of translations and print
   621 translation functions; potential INCOMPATIBILITY: need to reverse
   622 multiple declarations for same syntax element constant;
   623 
   624 * Pure/show_hyps reset by default (in accordance to existing Isar
   625 practice);
   626 
   627 * Provers/classical: renamed addaltern to addafter, addSaltern to
   628 addSafter;
   629 
   630 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   631 as well;
   632 
   633 * system: tested support for MacOS X; should be able to get Isabelle +
   634 Proof General to work in a plain Terminal after installing Poly/ML
   635 (e.g. from the Isabelle distribution area) and GNU bash alone
   636 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   637 support requires further installations, e.g. from
   638 http://fink.sourceforge.net/);
   639 
   640 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   641 
   642 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   643 of 40 MB), cf. ML_OPTIONS;
   644 
   645 * system: Proof General keywords specification is now part of the
   646 Isabelle distribution (see etc/isar-keywords.el);
   647 
   648 * system: support for persistent Proof General sessions (refrain from
   649 outdating all loaded theories on startup); user may create writable
   650 logic images like this: ``isabelle -q HOL Test'';
   651 
   652 * system: smart selection of Isabelle process versus Isabelle
   653 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   654 run both "isabelle" and "Isabelle" even if file names are badly
   655 damaged (executable inspects the case of the first letter of its own
   656 name); added separate "isabelle-process" and "isabelle-interface";
   657 
   658 * system: refrain from any attempt at filtering input streams; no
   659 longer support ``8bit'' encoding of old isabelle font, instead proper
   660 iso-latin characters may now be used; the related isatools
   661 "symbolinput" and "nonascii" have disappeared as well;
   662 
   663 * system: removed old "xterm" interface (the print modes "xterm" and
   664 "xterm_color" are still available for direct use in a suitable
   665 terminal);
   666 
   667 
   668 
   669 New in Isabelle99-2 (February 2001)
   670 -----------------------------------
   671 
   672 *** Overview of INCOMPATIBILITIES ***
   673 
   674 * HOL: please note that theories in the Library and elsewhere often use the
   675 new-style (Isar) format; to refer to their theorems in an ML script you must
   676 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   677 
   678 * HOL: inductive package no longer splits induction rule aggressively,
   679 but only as far as specified by the introductions given; the old
   680 format may be recovered via ML function complete_split_rule or attribute
   681 'split_rule (complete)';
   682 
   683 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   684 gfp_Tarski to gfp_unfold;
   685 
   686 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   687 
   688 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   689 relation); infix "^^" has been renamed "``"; infix "``" has been
   690 renamed "`"; "univalent" has been renamed "single_valued";
   691 
   692 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   693 operation;
   694 
   695 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   696 
   697 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   698 
   699 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   700 consequence, it is no longer monotonic wrt. the local goal context
   701 (which is now passed through the inductive cases);
   702 
   703 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   704 \<gg> to \<ggreater>;
   705 
   706 
   707 *** Document preparation ***
   708 
   709 * \isabellestyle{NAME} selects version of Isabelle output (currently
   710 available: are "it" for near math-mode best-style output, "sl" for
   711 slanted text style, and "tt" for plain type-writer; if no
   712 \isabellestyle command is given, output is according to slanted
   713 type-writer);
   714 
   715 * support sub/super scripts (for single symbols only), input syntax is
   716 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   717 
   718 * some more standard symbols; see Appendix A of the system manual for
   719 the complete list of symbols defined in isabellesym.sty;
   720 
   721 * improved isabelle style files; more abstract symbol implementation
   722 (should now use \isamath{...} and \isatext{...} in custom symbol
   723 definitions);
   724 
   725 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   726 state; Note that presentation of goal states does not conform to
   727 actual human-readable proof documents.  Please do not include goal
   728 states into document output unless you really know what you are doing!
   729 
   730 * proper indentation of antiquoted output with proportional LaTeX
   731 fonts;
   732 
   733 * no_document ML operator temporarily disables LaTeX document
   734 generation;
   735 
   736 * isatool unsymbolize tunes sources for plain ASCII communication;
   737 
   738 
   739 *** Isar ***
   740 
   741 * Pure: Isar now suffers initial goal statements to contain unbound
   742 schematic variables (this does not conform to actual readable proof
   743 documents, due to unpredictable outcome and non-compositional proof
   744 checking); users who know what they are doing may use schematic goals
   745 for Prolog-style synthesis of proven results;
   746 
   747 * Pure: assumption method (an implicit finishing) now handles actual
   748 rules as well;
   749 
   750 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   751 initial goal, declare "that" only as Pure intro (only for single
   752 steps); the "that" rule assumption may now be involved in implicit
   753 finishing, thus ".." becomes a feasible for trivial obtains;
   754 
   755 * Pure: default proof step now includes 'intro_classes'; thus trivial
   756 instance proofs may be performed by "..";
   757 
   758 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   759 statements as well;
   760 
   761 * Pure: more robust selection of calculational rules;
   762 
   763 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   764 rule (as well as the assumption rule);
   765 
   766 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   767 lemmas, using the graph browser tool;
   768 
   769 * Pure: predict failure of "show" in interactive mode;
   770 
   771 * Pure: 'thms_containing' now takes actual terms as arguments;
   772 
   773 * HOL: improved method 'induct' --- now handles non-atomic goals
   774 (potential INCOMPATIBILITY); tuned error handling;
   775 
   776 * HOL: cases and induct rules now provide explicit hints about the
   777 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   778 any remaining facts are inserted into the goal verbatim;
   779 
   780 * HOL: local contexts (aka cases) may now contain term bindings as
   781 well; the 'cases' and 'induct' methods new provide a ?case binding for
   782 the result to be shown in each case;
   783 
   784 * HOL: added 'recdef_tc' command;
   785 
   786 * isatool convert assists in eliminating legacy ML scripts;
   787 
   788 
   789 *** HOL ***
   790 
   791 * HOL/Library: a collection of generic theories to be used together
   792 with main HOL; the theory loader path already includes this directory
   793 by default; the following existing theories have been moved here:
   794 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   795 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   796 
   797 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   798 modelling and verification task performed in Isabelle/HOL +
   799 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   800 
   801 * HOL/Algebra: special summation operator SUM no longer exists, it has
   802 been replaced by setsum; infix 'assoc' now has priority 50 (like
   803 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   804 'domain', this makes the theory consistent with mathematical
   805 literature;
   806 
   807 * HOL basics: added overloaded operations "inverse" and "divide"
   808 (infix "/"), syntax for generic "abs" operation, generic summation
   809 operator \<Sum>;
   810 
   811 * HOL/typedef: simplified package, provide more useful rules (see also
   812 HOL/subset.thy);
   813 
   814 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   815 now expressed as a proper nested rule (old-style tactic scripts may
   816 require atomize_strip_tac to cope with non-atomic premises);
   817 
   818 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   819 to "split_conv" (old name still available for compatibility);
   820 
   821 * HOL: improved concrete syntax for strings (e.g. allows translation
   822 rules with string literals);
   823 
   824 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   825  and Fleuriot's mechanization of analysis, including the transcendental
   826  functions for the reals;
   827 
   828 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   829 
   830 
   831 *** CTT ***
   832 
   833 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   834 "lam" is displayed as TWO lambda-symbols
   835 
   836 * CTT: theory Main now available, containing everything (that is, Bool
   837 and Arith);
   838 
   839 
   840 *** General ***
   841 
   842 * Pure: the Simplifier has been implemented properly as a derived rule
   843 outside of the actual kernel (at last!); the overall performance
   844 penalty in practical applications is about 50%, while reliability of
   845 the Isabelle inference kernel has been greatly improved;
   846 
   847 * print modes "brackets" and "no_brackets" control output of nested =>
   848 (types) and ==> (props); the default behaviour is "brackets";
   849 
   850 * Provers: fast_tac (and friends) now handle actual object-logic rules
   851 as assumptions as well;
   852 
   853 * system: support Poly/ML 4.0;
   854 
   855 * system: isatool install handles KDE version 1 or 2;
   856 
   857 
   858 
   859 New in Isabelle99-1 (October 2000)
   860 ----------------------------------
   861 
   862 *** Overview of INCOMPATIBILITIES ***
   863 
   864 * HOL: simplification of natural numbers is much changed; to partly
   865 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   866 issue the following ML commands:
   867 
   868   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   869   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   870 
   871 * HOL: simplification no longer dives into case-expressions; this is
   872 controlled by "t.weak_case_cong" for each datatype t;
   873 
   874 * HOL: nat_less_induct renamed to less_induct;
   875 
   876 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   877 fixsome to patch .thy and .ML sources automatically;
   878 
   879   select_equality  -> some_equality
   880   select_eq_Ex     -> some_eq_ex
   881   selectI2EX       -> someI2_ex
   882   selectI2         -> someI2
   883   selectI          -> someI
   884   select1_equality -> some1_equality
   885   Eps_sym_eq       -> some_sym_eq_trivial
   886   Eps_eq           -> some_eq_trivial
   887 
   888 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   889 
   890 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   891 instead);
   892 
   893 * HOL: the recursion equations generated by 'recdef' are now called
   894 f.simps instead of f.rules;
   895 
   896 * HOL: qed_spec_mp now also handles bounded ALL as well;
   897 
   898 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   899 sometimes be needed;
   900 
   901 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   902 
   903 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   904 
   905 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   906 product is now "<*>" instead of "Times"; the lexicographic product is
   907 now "<*lex*>" instead of "**";
   908 
   909 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   910 of main HOL, but was unused); better use HOL's datatype package;
   911 
   912 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   913 the old syntax may be recovered as follows:
   914 
   915   syntax (symbols)
   916     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   917       (infixl "\\<oplus>" 100)
   918 
   919 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   920 
   921 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   922 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   923 internally;
   924 
   925 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   926 changed from A/r to A//r;
   927 
   928 * ZF: new treatment of arithmetic (nat & int) may break some old
   929 proofs;
   930 
   931 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   932 rulify -> rule_format, elimify -> elim_format, ...);
   933 
   934 * Isar/Provers: intro/elim/dest attributes changed; renamed
   935 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   936 should have to change intro!! to intro? only); replaced "delrule" by
   937 "rule del";
   938 
   939 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   940 
   941 * Provers: strengthened force_tac by using new first_best_tac;
   942 
   943 * LaTeX document preparation: several changes of isabelle.sty (see
   944 lib/texinputs);
   945 
   946 
   947 *** Document preparation ***
   948 
   949 * formal comments (text blocks etc.) in new-style theories may now
   950 contain antiquotations of thm/prop/term/typ/text to be presented
   951 according to latex print mode; concrete syntax is like this:
   952 @{term[show_types] "f(x) = a + x"};
   953 
   954 * isatool mkdir provides easy setup of Isabelle session directories,
   955 including proper document sources;
   956 
   957 * generated LaTeX sources are now deleted after successful run
   958 (isatool document -c); may retain a copy somewhere else via -D option
   959 of isatool usedir;
   960 
   961 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   962 style files, achieving self-contained LaTeX sources and simplifying
   963 LaTeX debugging;
   964 
   965 * old-style theories now produce (crude) LaTeX output as well;
   966 
   967 * browser info session directories are now self-contained (may be put
   968 on WWW server seperately); improved graphs of nested sessions; removed
   969 graph for 'all sessions';
   970 
   971 * several improvements in isabelle style files; \isabellestyle{it}
   972 produces fake math mode output; \isamarkupheader is now \section by
   973 default; see lib/texinputs/isabelle.sty etc.;
   974 
   975 
   976 *** Isar ***
   977 
   978 * Isar/Pure: local results and corresponding term bindings are now
   979 subject to Hindley-Milner polymorphism (similar to ML); this
   980 accommodates incremental type-inference very nicely;
   981 
   982 * Isar/Pure: new derived language element 'obtain' supports
   983 generalized existence reasoning;
   984 
   985 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   986 support accumulation of results, without applying any rules yet;
   987 useful to collect intermediate results without explicit name
   988 references, and for use with transitivity rules with more than 2
   989 premises;
   990 
   991 * Isar/Pure: scalable support for case-analysis type proofs: new
   992 'case' language element refers to local contexts symbolically, as
   993 produced by certain proof methods; internally, case names are attached
   994 to theorems as "tags";
   995 
   996 * Isar/Pure: theory command 'hide' removes declarations from
   997 class/type/const name spaces;
   998 
   999 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1000 indicate potential overloading;
  1001 
  1002 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1003 
  1004 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1005 "{a,b,c}" instead of {a,b,c};
  1006 
  1007 * Isar/Pure now provides its own version of intro/elim/dest
  1008 attributes; useful for building new logics, but beware of confusion
  1009 with the version in Provers/classical;
  1010 
  1011 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1012 case name 'antecedent';
  1013 
  1014 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1015 to the current context is now done automatically);
  1016 
  1017 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1018 for definining proof methods in ML;
  1019 
  1020 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1021 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1022 most cases, one should have to change intro!! to intro? only);
  1023 replaced "delrule" by "rule del";
  1024 
  1025 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1026 'symmetric' attribute (the latter supercedes [RS sym]);
  1027 
  1028 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1029 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1030 well (including splits);
  1031 
  1032 * Isar/Provers: Simplifier and Classical methods now support all kind
  1033 of modifiers used in the past, including 'cong', 'iff', etc.
  1034 
  1035 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1036 of Simplifier and Classical reasoner);
  1037 
  1038 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1039 now support named cases; major packages (inductive, datatype, primrec,
  1040 recdef) support case names and properly name parameters;
  1041 
  1042 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1043 monotonicity conditions are extracted to be proven at end of
  1044 calculations;
  1045 
  1046 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1047 method anyway;
  1048 
  1049 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1050 split_if split_if_asm; datatype package provides theorems foo.splits =
  1051 foo.split foo.split_asm for each datatype;
  1052 
  1053 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1054 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1055 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1056 use "(cases (simplified))" method in proper proof texts);
  1057 
  1058 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1059 
  1060 * Isar: names of theorems etc. may be natural numbers as well;
  1061 
  1062 * Isar: 'pr' command: optional arguments for goals_limit and
  1063 ProofContext.prems_limit; no longer prints theory contexts, but only
  1064 proof states;
  1065 
  1066 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1067 additional print modes to be specified; e.g. "pr(latex)" will print
  1068 proof state according to the Isabelle LaTeX style;
  1069 
  1070 * Isar: improved support for emulating tactic scripts, including proof
  1071 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1072 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1073 (for HOL datatypes);
  1074 
  1075 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1076 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1077 'proof method scripts' have to be in depth-first order;
  1078 
  1079 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1080 
  1081 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1082 should instead use individual commands for printing items
  1083 (print_commands, print_methods etc.);
  1084 
  1085 * Isar: added 'nothing' --- the empty list of theorems;
  1086 
  1087 
  1088 *** HOL ***
  1089 
  1090 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1091 corresponding virtual machine and a specification of its bytecode
  1092 verifier and a lightweight bytecode verifier, including proofs of
  1093 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1094 Cornelia Pusch (see also the homepage of project Bali at
  1095 http://isabelle.in.tum.de/Bali/);
  1096 
  1097 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1098 Clemens Ballarin;
  1099 
  1100 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1101 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1102 Rasmussen;
  1103 
  1104 * HOL/Lattice: fundamental concepts of lattice theory and order
  1105 structures, including duals, properties of bounds versus algebraic
  1106 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1107 Theorem for complete lattices etc.; may also serve as a demonstration
  1108 for abstract algebraic reasoning using axiomatic type classes, and
  1109 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1110 
  1111 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1112 von Oheimb;
  1113 
  1114 * HOL/IMPP: extension of IMP with local variables and mutually
  1115 recursive procedures, by David von Oheimb;
  1116 
  1117 * HOL/Lambda: converted into new-style theory and document;
  1118 
  1119 * HOL/ex/Multiquote: example of multiple nested quotations and
  1120 anti-quotations -- basically a generalized version of de-Bruijn
  1121 representation; very useful in avoiding lifting of operations;
  1122 
  1123 * HOL/record: added general record equality rule to simpset; fixed
  1124 select-update simplification procedure to handle extended records as
  1125 well; admit "r" as field name;
  1126 
  1127 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1128 other numeric types and also as the identity of groups, rings, etc.;
  1129 
  1130 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1131 Types nat and int belong to this axclass;
  1132 
  1133 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1134    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1135    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1136   two terms #m*u and #n*u are replaced by #(m+n)*u
  1137     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1138   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1139     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1140 
  1141 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1142 powerful prover for predicate logic but knows nothing of clasets; see
  1143 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1144 
  1145 * HOL: new version of "case_tac" subsumes both boolean case split and
  1146 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1147 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1148 
  1149 * HOL: simplification no longer dives into case-expressions: only the
  1150 selector expression is simplified, but not the remaining arms; to
  1151 enable full simplification of case-expressions for datatype t, you may
  1152 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1153 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1154 
  1155 * HOL/recdef: the recursion equations generated by 'recdef' for
  1156 function 'f' are now called f.simps instead of f.rules; if all
  1157 termination conditions are proved automatically, these simplification
  1158 rules are added to the simpset, as in primrec; rules may be named
  1159 individually as well, resulting in a separate list of theorems for
  1160 each equation;
  1161 
  1162 * HOL/While is a new theory that provides a while-combinator. It
  1163 permits the definition of tail-recursive functions without the
  1164 provision of a termination measure. The latter is necessary once the
  1165 invariant proof rule for while is applied.
  1166 
  1167 * HOL: new (overloaded) notation for the set of elements below/above
  1168 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1169 
  1170 * HOL: theorems impI, allI, ballI bound as "strip";
  1171 
  1172 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1173 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1174 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1175 
  1176 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1177 
  1178 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1179 main HOL, but was unused);
  1180 
  1181 * HOL: fewer consts declared as global (e.g. have to refer to
  1182 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1183 
  1184 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1185 in case of overlap with user translations (e.g. judgements over
  1186 tuples); (note that the underlying logical represenation is still
  1187 bogus);
  1188 
  1189 
  1190 *** ZF ***
  1191 
  1192 * ZF: simplification automatically cancels common terms in arithmetic
  1193 expressions over nat and int;
  1194 
  1195 * ZF: new treatment of nat to minimize type-checking: all operators
  1196 coerce their operands to a natural number using the function natify,
  1197 making the algebraic laws unconditional;
  1198 
  1199 * ZF: as above, for int: operators coerce their operands to an integer
  1200 using the function intify;
  1201 
  1202 * ZF: the integer library now contains many of the usual laws for the
  1203 orderings, including $<=, and monotonicity laws for $+ and $*;
  1204 
  1205 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1206 simplification;
  1207 
  1208 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1209 to the simplifier and classical reasoner simultaneously;
  1210 
  1211 
  1212 *** General ***
  1213 
  1214 * Provers: blast_tac now handles actual object-logic rules as
  1215 assumptions; note that auto_tac uses blast_tac internally as well;
  1216 
  1217 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1218 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1219 
  1220 * Provers: delrules now handles destruct rules as well (no longer need
  1221 explicit make_elim);
  1222 
  1223 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1224   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1225 use instead the strong form,
  1226   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1227 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1228 from destruct-rules;
  1229 
  1230 * Provers: Simplifier.easy_setup provides a fast path to basic
  1231 Simplifier setup for new object-logics;
  1232 
  1233 * Pure: AST translation rules no longer require constant head on LHS;
  1234 
  1235 * Pure: improved name spaces: ambiguous output is qualified; support
  1236 for hiding of names;
  1237 
  1238 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1239 XSYMBOL_HOME; no longer need to do manual configuration in most
  1240 situations;
  1241 
  1242 * system: compression of ML heaps images may now be controlled via -c
  1243 option of isabelle and isatool usedir (currently only observed by
  1244 Poly/ML);
  1245 
  1246 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1247 useful for remote X11);
  1248 
  1249 * system: provide TAGS file for Isabelle sources;
  1250 
  1251 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1252 order;
  1253 
  1254 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1255 timing flag supersedes proof_timing and Toplevel.trace;
  1256 
  1257 * ML: new combinators |>> and |>>> for incremental transformations
  1258 with secondary results (e.g. certain theory extensions):
  1259 
  1260 * ML: PureThy.add_defs gets additional argument to indicate potential
  1261 overloading (usually false);
  1262 
  1263 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1264 results;
  1265 
  1266 
  1267 
  1268 New in Isabelle99 (October 1999)
  1269 --------------------------------
  1270 
  1271 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1272 
  1273 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1274 are no longer simplified.  (This allows the simplifier to unfold recursive
  1275 functional programs.)  To restore the old behaviour, declare
  1276 
  1277     Delcongs [if_weak_cong];
  1278 
  1279 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1280 complement;
  1281 
  1282 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1283 
  1284 * HOL/datatype: mutual_induct_tac no longer exists --
  1285   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1286 
  1287 * HOL/typedef: fixed type inference for representing set; type
  1288 arguments now have to occur explicitly on the rhs as type constraints;
  1289 
  1290 * ZF: The con_defs part of an inductive definition may no longer refer
  1291 to constants declared in the same theory;
  1292 
  1293 * HOL, ZF: the function mk_cases, generated by the inductive
  1294 definition package, has lost an argument.  To simplify its result, it
  1295 uses the default simpset instead of a supplied list of theorems.
  1296 
  1297 * HOL/List: the constructors of type list are now Nil and Cons;
  1298 
  1299 * Simplifier: the type of the infix ML functions
  1300         setSSolver addSSolver setSolver addSolver
  1301 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1302 for packaging solvers. A solver is created via
  1303         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1304 where the string argument is only a comment.
  1305 
  1306 
  1307 *** Proof tools ***
  1308 
  1309 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1310 decision procedure for linear arithmetic. Currently it is used for
  1311 types `nat', `int', and `real' in HOL (see below); it can, should and
  1312 will be instantiated for other types and logics as well.
  1313 
  1314 * The simplifier now accepts rewrite rules with flexible heads, eg
  1315      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1316   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1317   matching.
  1318 
  1319 
  1320 *** General ***
  1321 
  1322 * New Isabelle/Isar subsystem provides an alternative to traditional
  1323 tactical theorem proving; together with the ProofGeneral/isar user
  1324 interface it offers an interactive environment for developing human
  1325 readable proof documents (Isar == Intelligible semi-automated
  1326 reasoning); for further information see isatool doc isar-ref,
  1327 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1328 
  1329 * improved and simplified presentation of theories: better HTML markup
  1330 (including colors), graph views in several sizes; isatool usedir now
  1331 provides a proper interface for user theories (via -P option); actual
  1332 document preparation based on (PDF)LaTeX is available as well (for
  1333 new-style theories only); see isatool doc system for more information;
  1334 
  1335 * native support for Proof General, both for classic Isabelle and
  1336 Isabelle/Isar;
  1337 
  1338 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1339 using the graph browser tool;
  1340 
  1341 * Isabelle manuals now also available as PDF;
  1342 
  1343 * theory loader rewritten from scratch (may not be fully
  1344 bug-compatible); old loadpath variable has been replaced by show_path,
  1345 add_path, del_path, reset_path functions; new operations such as
  1346 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1347 isatool doc ref);
  1348 
  1349 * improved isatool install: option -k creates KDE application icon,
  1350 option -p DIR installs standalone binaries;
  1351 
  1352 * added ML_PLATFORM setting (useful for cross-platform installations);
  1353 more robust handling of platform specific ML images for SML/NJ;
  1354 
  1355 * the settings environment is now statically scoped, i.e. it is never
  1356 created again in sub-processes invoked from isabelle, isatool, or
  1357 Isabelle;
  1358 
  1359 * path element specification '~~' refers to '$ISABELLE_HOME';
  1360 
  1361 * in locales, the "assumes" and "defines" parts may be omitted if
  1362 empty;
  1363 
  1364 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1365 long arrows);
  1366 
  1367 * new print_mode "HTML";
  1368 
  1369 * new flag show_tags controls display of tags of theorems (which are
  1370 basically just comments that may be attached by some tools);
  1371 
  1372 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1373 mode and goal output format:
  1374 
  1375 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1376 244c244
  1377 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1378 ---
  1379 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1380 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1381 181c181
  1382 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1383 ---
  1384 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1385 
  1386 * function bind_thms stores lists of theorems (cf. bind_thm);
  1387 
  1388 * new shorthand tactics ftac, eatac, datac, fatac;
  1389 
  1390 * qed (and friends) now accept "" as result name; in that case the
  1391 theorem is not stored, but proper checks and presentation of the
  1392 result still apply;
  1393 
  1394 * theorem database now also indexes constants "Trueprop", "all",
  1395 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1396 
  1397 
  1398 *** HOL ***
  1399 
  1400 ** HOL arithmetic **
  1401 
  1402 * There are now decision procedures for linear arithmetic over nat and
  1403 int:
  1404 
  1405 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1406 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1407 are treated as atomic; subformulae not involving type `nat' or `int'
  1408 are ignored; quantified subformulae are ignored unless they are
  1409 positive universal or negative existential. The tactic has to be
  1410 invoked by hand and can be a little bit slow. In particular, the
  1411 running time is exponential in the number of occurrences of `min' and
  1412 `max', and `-' on `nat'.
  1413 
  1414 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1415 (negated) (in)equalities among the premises and the conclusion into
  1416 account (i.e. no compound formulae) and does not know about `min' and
  1417 `max', and `-' on `nat'. It is fast and is used automatically by the
  1418 simplifier.
  1419 
  1420 NB: At the moment, these decision procedures do not cope with mixed
  1421 nat/int formulae where the two parts interact, such as `m < n ==>
  1422 int(m) < int(n)'.
  1423 
  1424 * HOL/Numeral provides a generic theory of numerals (encoded
  1425 efficiently as bit strings); setup for types nat/int/real is in place;
  1426 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1427 int, existing theories and proof scripts may require a few additional
  1428 type constraints;
  1429 
  1430 * integer division and remainder can now be performed on constant
  1431 arguments;
  1432 
  1433 * many properties of integer multiplication, division and remainder
  1434 are now available;
  1435 
  1436 * An interface to the Stanford Validity Checker (SVC) is available through the
  1437 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1438 are proved automatically.  SVC must be installed separately, and its results
  1439 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1440 invocation of the underlying oracle).  For SVC see
  1441   http://verify.stanford.edu/SVC
  1442 
  1443 * IsaMakefile: the HOL-Real target now builds an actual image;
  1444 
  1445 
  1446 ** HOL misc **
  1447 
  1448 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1449 (in Isabelle/Isar) -- by Gertrud Bauer;
  1450 
  1451 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1452 analysis for assembly languages with subtypes;
  1453 
  1454 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1455 -- avoids syntactic ambiguities and treats state, transition, and
  1456 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1457 changed syntax and (many) tactics;
  1458 
  1459 * HOL/inductive: Now also handles more general introduction rules such
  1460   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1461   theorems are now maintained within the theory (maintained via the
  1462   "mono" attribute);
  1463 
  1464 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1465   (using function types) such as
  1466 
  1467   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1468 
  1469 * HOL/record: record_simproc (part of the default simpset) takes care
  1470 of selectors applied to updated records; record_split_tac is no longer
  1471 part of the default claset; update_defs may now be removed from the
  1472 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1473 
  1474   claset_ref () := claset() addSWrapper record_split_wrapper;
  1475   Delsimprocs [record_simproc]
  1476 
  1477 * HOL/typedef: fixed type inference for representing set; type
  1478 arguments now have to occur explicitly on the rhs as type constraints;
  1479 
  1480 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1481 names rather than an ML expression;
  1482 
  1483 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1484 supplied later.  Program schemes can be defined, such as
  1485     "While B C s = (if B s then While B C (C s) else s)"
  1486 where the well-founded relation can be chosen after B and C have been given.
  1487 
  1488 * HOL/List: the constructors of type list are now Nil and Cons;
  1489 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1490 course, ML tools referring to List.list.op # etc. have to be adapted;
  1491 
  1492 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1493 disabled by default; run isabelle with option -m HOL to get back to
  1494 the original Gordon/HOL-style output;
  1495 
  1496 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1497 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1498 
  1499 * HOL basic syntax simplified (more orthogonal): all variants of
  1500 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1501 Eps operator is provided as well: "SOME x. P[x]";
  1502 
  1503 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1504 
  1505 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1506 thus available for user theories;
  1507 
  1508 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1509 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1510 time;
  1511 
  1512 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1513 several times and then mp;
  1514 
  1515 
  1516 *** LK ***
  1517 
  1518 * the notation <<...>> is now available as a notation for sequences of
  1519 formulas;
  1520 
  1521 * the simplifier is now installed
  1522 
  1523 * the axiom system has been generalized (thanks to Soren Heilmann)
  1524 
  1525 * the classical reasoner now has a default rule database
  1526 
  1527 
  1528 *** ZF ***
  1529 
  1530 * new primrec section allows primitive recursive functions to be given
  1531 directly (as in HOL) over datatypes and the natural numbers;
  1532 
  1533 * new tactics induct_tac and exhaust_tac for induction (or case
  1534 analysis) over datatypes and the natural numbers;
  1535 
  1536 * the datatype declaration of type T now defines the recursor T_rec;
  1537 
  1538 * simplification automatically does freeness reasoning for datatype
  1539 constructors;
  1540 
  1541 * automatic type-inference, with AddTCs command to insert new
  1542 type-checking rules;
  1543 
  1544 * datatype introduction rules are now added as Safe Introduction rules
  1545 to the claset;
  1546 
  1547 * the syntax "if P then x else y" is now available in addition to
  1548 if(P,x,y);
  1549 
  1550 
  1551 *** Internal programming interfaces ***
  1552 
  1553 * tuned simplifier trace output; new flag debug_simp;
  1554 
  1555 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1556 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1557 
  1558 * AxClass.axclass_tac lost the theory argument;
  1559 
  1560 * tuned current_goals_markers semantics: begin / end goal avoids
  1561 printing empty lines;
  1562 
  1563 * removed prs and prs_fn hook, which was broken because it did not
  1564 include \n in its semantics, forcing writeln to add one
  1565 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1566 string -> unit if you really want to output text without newline;
  1567 
  1568 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1569 plain output, interface builders may have to enable 'isabelle_font'
  1570 mode to get Isabelle font glyphs as before;
  1571 
  1572 * refined token_translation interface; INCOMPATIBILITY: output length
  1573 now of type real instead of int;
  1574 
  1575 * theory loader actions may be traced via new ThyInfo.add_hook
  1576 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1577 your own database of information attached to *whole* theories -- as
  1578 opposed to intra-theory data slots offered via TheoryDataFun;
  1579 
  1580 * proper handling of dangling sort hypotheses (at last!);
  1581 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1582 extra sort hypotheses that can be witnessed from the type signature;
  1583 the force_strip_shyps flag is gone, any remaining shyps are simply
  1584 left in the theorem (with a warning issued by strip_shyps_warning);
  1585 
  1586 
  1587 
  1588 New in Isabelle98-1 (October 1998)
  1589 ----------------------------------
  1590 
  1591 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1592 
  1593 * several changes of automated proof tools;
  1594 
  1595 * HOL: major changes to the inductive and datatype packages, including
  1596 some minor incompatibilities of theory syntax;
  1597 
  1598 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1599 called `inj_on';
  1600 
  1601 * HOL: removed duplicate thms in Arith:
  1602   less_imp_add_less  should be replaced by  trans_less_add1
  1603   le_imp_add_le      should be replaced by  trans_le_add1
  1604 
  1605 * HOL: unary minus is now overloaded (new type constraints may be
  1606 required);
  1607 
  1608 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1609 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1610 now taken as an integer constant.
  1611 
  1612 * Pure: ML function 'theory_of' renamed to 'theory';
  1613 
  1614 
  1615 *** Proof tools ***
  1616 
  1617 * Simplifier:
  1618   1. Asm_full_simp_tac is now more aggressive.
  1619      1. It will sometimes reorient premises if that increases their power to
  1620         simplify.
  1621      2. It does no longer proceed strictly from left to right but may also
  1622         rotate premises to achieve further simplification.
  1623      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1624      old Asm_full_simp_tac in that it does not rotate premises.
  1625   2. The simplifier now knows a little bit about nat-arithmetic.
  1626 
  1627 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1628 allows for selected deletion of wrappers, by introduction of names for
  1629 wrapper functionals.  This implies that addbefore, addSbefore,
  1630 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1631 and that adding two tactics with the same name overwrites the first
  1632 one (emitting a warning).
  1633   type wrapper = (int -> tactic) -> (int -> tactic)
  1634   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1635   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1636   delWrapper, delSWrapper: claset *  string            -> claset
  1637   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1638 
  1639 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1640 semantics; addbefore now affects only the unsafe part of step_tac
  1641 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1642 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1643 by Force_tac;
  1644 
  1645 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1646 compWrapper; added safe wrapper (and access functions for it);
  1647 
  1648 * HOL/split_all_tac is now much faster and fails if there is nothing
  1649 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1650 and the names of the automatically generated variables have changed.
  1651 split_all_tac has moved within claset() from unsafe wrappers to safe
  1652 wrappers, which means that !!-bound variables are split much more
  1653 aggressively, and safe_tac and clarify_tac now split such variables.
  1654 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1655 Note: the same holds for record_split_tac, which does the job of
  1656 split_all_tac for record fields.
  1657 
  1658 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1659 permanently to the default simpset using Addsplits just like
  1660 Addsimps. They can be removed via Delsplits just like
  1661 Delsimps. Lower-case versions are also available.
  1662 
  1663 * HOL/Simplifier: The rule split_if is now part of the default
  1664 simpset. This means that the simplifier will eliminate all occurrences
  1665 of if-then-else in the conclusion of a goal. To prevent this, you can
  1666 either remove split_if completely from the default simpset by
  1667 `Delsplits [split_if]' or remove it in a specific call of the
  1668 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1669 other case splitting rules to/from the default simpset: every datatype
  1670 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1671 t is the name of the datatype).
  1672 
  1673 * Classical reasoner / Simplifier combination: new force_tac (and
  1674 derivatives Force_tac, force) combines rewriting and classical
  1675 reasoning (and whatever other tools) similarly to auto_tac, but is
  1676 aimed to solve the given subgoal completely.
  1677 
  1678 
  1679 *** General ***
  1680 
  1681 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1682 and `goalw': the theory is no longer needed as an explicit argument -
  1683 the current theory context is used; assumptions are no longer returned
  1684 at the ML-level unless one of them starts with ==> or !!; it is
  1685 recommended to convert to these new commands using isatool fixgoal
  1686 (backup your sources first!);
  1687 
  1688 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1689 the current theory context, and 'theory' to lookup stored theories;
  1690 
  1691 * new theory section 'locale' for declaring constants, assumptions and
  1692 definitions that have local scope;
  1693 
  1694 * new theory section 'nonterminals' for purely syntactic types;
  1695 
  1696 * new theory section 'setup' for generic ML setup functions
  1697 (e.g. package initialization);
  1698 
  1699 * the distribution now includes Isabelle icons: see
  1700 lib/logo/isabelle-{small,tiny}.xpm;
  1701 
  1702 * isatool install - install binaries with absolute references to
  1703 ISABELLE_HOME/bin;
  1704 
  1705 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1706 
  1707 * print mode 'emacs' reserved for Isamode;
  1708 
  1709 * support multiple print (ast) translations per constant name;
  1710 
  1711 * theorems involving oracles are now printed with a suffixed [!];
  1712 
  1713 
  1714 *** HOL ***
  1715 
  1716 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1717 
  1718 * HOL/inductive package reorganized and improved: now supports mutual
  1719 definitions such as
  1720 
  1721   inductive EVEN ODD
  1722     intrs
  1723       null "0 : EVEN"
  1724       oddI "n : EVEN ==> Suc n : ODD"
  1725       evenI "n : ODD ==> Suc n : EVEN"
  1726 
  1727 new theorem list "elims" contains an elimination rule for each of the
  1728 recursive sets; inductive definitions now handle disjunctive premises
  1729 correctly (also ZF);
  1730 
  1731 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1732 "mutual_induct" no longer exists - the induction rule is always
  1733 contained in "induct";
  1734 
  1735 
  1736 * HOL/datatype package re-implemented and greatly improved: now
  1737 supports mutually recursive datatypes such as
  1738 
  1739   datatype
  1740     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1741             | SUM ('a aexp) ('a aexp)
  1742             | DIFF ('a aexp) ('a aexp)
  1743             | NUM 'a
  1744   and
  1745     'a bexp = LESS ('a aexp) ('a aexp)
  1746             | AND ('a bexp) ('a bexp)
  1747             | OR ('a bexp) ('a bexp)
  1748 
  1749 as well as indirectly recursive datatypes such as
  1750 
  1751   datatype
  1752     ('a, 'b) term = Var 'a
  1753                   | App 'b ((('a, 'b) term) list)
  1754 
  1755 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1756 induction on mutually / indirectly recursive datatypes.
  1757 
  1758 Primrec equations are now stored in theory and can be accessed via
  1759 <function_name>.simps.
  1760 
  1761 INCOMPATIBILITIES:
  1762 
  1763   - Theories using datatypes must now have theory Datatype as an
  1764     ancestor.
  1765   - The specific <typename>.induct_tac no longer exists - use the
  1766     generic induct_tac instead.
  1767   - natE has been renamed to nat.exhaust - use exhaust_tac
  1768     instead of res_inst_tac ... natE. Note that the variable
  1769     names in nat.exhaust differ from the names in natE, this
  1770     may cause some "fragile" proofs to fail.
  1771   - The theorems split_<typename>_case and split_<typename>_case_asm
  1772     have been renamed to <typename>.split and <typename>.split_asm.
  1773   - Since default sorts of type variables are now handled correctly,
  1774     some datatype definitions may have to be annotated with explicit
  1775     sort constraints.
  1776   - Primrec definitions no longer require function name and type
  1777     of recursive argument.
  1778 
  1779 Consider using isatool fixdatatype to adapt your theories and proof
  1780 scripts to the new package (backup your sources first!).
  1781 
  1782 
  1783 * HOL/record package: considerably improved implementation; now
  1784 includes concrete syntax for record types, terms, updates; theorems
  1785 for surjective pairing and splitting !!-bound record variables; proof
  1786 support is as follows:
  1787 
  1788   1) standard conversions (selectors or updates applied to record
  1789 constructor terms) are part of the standard simpset;
  1790 
  1791   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1792 made part of standard simpset and claset via addIffs;
  1793 
  1794   3) a tactic for record field splitting (record_split_tac) is part of
  1795 the standard claset (addSWrapper);
  1796 
  1797 To get a better idea about these rules you may retrieve them via
  1798 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1799 the name of your record type.
  1800 
  1801 The split tactic 3) conceptually simplifies by the following rule:
  1802 
  1803   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1804 
  1805 Thus any record variable that is bound by meta-all will automatically
  1806 blow up into some record constructor term, consequently the
  1807 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1808 solve record problems automatically.
  1809 
  1810 
  1811 * reorganized the main HOL image: HOL/Integ and String loaded by
  1812 default; theory Main includes everything;
  1813 
  1814 * automatic simplification of integer sums and comparisons, using cancellation;
  1815 
  1816 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1817 
  1818 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1819 
  1820 * many new identities for unions, intersections, set difference, etc.;
  1821 
  1822 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1823 called split_if, split_split, split_sum_case and split_nat_case (to go
  1824 with add/delsplits);
  1825 
  1826 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1827 (?x::unit) = (); this is made part of the default simpset, which COULD
  1828 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1829 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1830 unit_abs_eta_conv is added in order to counter the effect of
  1831 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1832 %u.f();
  1833 
  1834 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1835 makes more sense);
  1836 
  1837 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1838   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1839   disjointness reasoning but breaking a few old proofs.
  1840 
  1841 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1842 to 'converse' from 'inverse' (for compatibility with ZF and some
  1843 literature);
  1844 
  1845 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1846 the well-founded relation;
  1847 
  1848 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1849     Compl A.  The "Compl" syntax remains available as input syntax for this
  1850     release ONLY.
  1851 
  1852 * HOL/Update: new theory of function updates:
  1853     f(a:=b) == %x. if x=a then b else f x
  1854 may also be iterated as in f(a:=b,c:=d,...);
  1855 
  1856 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1857 
  1858 * HOL/List:
  1859   - new function list_update written xs[i:=v] that updates the i-th
  1860     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1861   - new function `upt' written [i..j(] which generates the list
  1862     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1863     bound write [i..j], which is a shorthand for [i..j+1(].
  1864   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1865 
  1866 * HOL/Arith:
  1867   - removed 'pred' (predecessor) function;
  1868   - generalized some theorems about n-1;
  1869   - many new laws about "div" and "mod";
  1870   - new laws about greatest common divisors (see theory ex/Primes);
  1871 
  1872 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1873 instead of "inverse";
  1874 
  1875 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1876   of the multiset ordering;
  1877 
  1878 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1879   (not included by default);
  1880 
  1881 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1882 
  1883 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1884   programs, i.e. different program variables may have different types.
  1885 
  1886 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1887   [previously, this check worked only if the rewrite rule was unconditional]
  1888   Now rew can involve either definitions or equalities (either == or =).
  1889 
  1890 
  1891 *** ZF ***
  1892 
  1893 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1894   only the theorems proved on ZF.ML;
  1895 
  1896 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1897   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1898   disjointness reasoning but breaking a few old proofs.
  1899 
  1900 * ZF/Update: new theory of function updates
  1901     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1902   may also be iterated as in f(a:=b,c:=d,...);
  1903 
  1904 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1905 
  1906 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1907   [previously, this check worked only if the rewrite rule was unconditional]
  1908   Now rew can involve either definitions or equalities (either == or =).
  1909 
  1910 * case_tac provided for compatibility with HOL
  1911     (like the old excluded_middle_tac, but with subgoals swapped)
  1912 
  1913 
  1914 *** Internal programming interfaces ***
  1915 
  1916 * Pure: several new basic modules made available for general use, see
  1917 also src/Pure/README;
  1918 
  1919 * improved the theory data mechanism to support encapsulation (data
  1920 kind name replaced by private Object.kind, acting as authorization
  1921 key); new type-safe user interface via functor TheoryDataFun; generic
  1922 print_data function becomes basically useless;
  1923 
  1924 * removed global_names compatibility flag -- all theory declarations
  1925 are qualified by default;
  1926 
  1927 * module Pure/Syntax now offers quote / antiquote translation
  1928 functions (useful for Hoare logic etc. with implicit dependencies);
  1929 see HOL/ex/Antiquote for an example use;
  1930 
  1931 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1932 cterm -> thm;
  1933 
  1934 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1935 subgoal;
  1936 
  1937 * Display.print_goals function moved to Locale.print_goals;
  1938 
  1939 * standard print function for goals supports current_goals_markers
  1940 variable for marking begin of proof, end of proof, start of goal; the
  1941 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1942 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1943 for example;
  1944 
  1945 
  1946 
  1947 New in Isabelle98 (January 1998)
  1948 --------------------------------
  1949 
  1950 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1951 
  1952 * changed lexical syntax of terms / types: dots made part of long
  1953 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1954 
  1955 * simpset (and claset) reference variable replaced by functions
  1956 simpset / simpset_ref;
  1957 
  1958 * no longer supports theory aliases (via merge) and non-trivial
  1959 implicit merge of thms' signatures;
  1960 
  1961 * most internal names of constants changed due to qualified names;
  1962 
  1963 * changed Pure/Sequence interface (see Pure/seq.ML);
  1964 
  1965 
  1966 *** General Changes ***
  1967 
  1968 * hierachically structured name spaces (for consts, types, axms, thms
  1969 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1970 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1971 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1972 long_names for fully qualified output names; NOTE: ML programs
  1973 (special tactics, packages etc.) referring to internal names may have
  1974 to be adapted to cope with fully qualified names; in case of severe
  1975 backward campatibility problems try setting 'global_names' at compile
  1976 time to have enrything declared within a flat name space; one may also
  1977 fine tune name declarations in theories via the 'global' and 'local'
  1978 section;
  1979 
  1980 * reimplemented the implicit simpset and claset using the new anytype
  1981 data filed in signatures; references simpset:simpset ref etc. are
  1982 replaced by functions simpset:unit->simpset and
  1983 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1984 to patch your ML files accordingly;
  1985 
  1986 * HTML output now includes theory graph data for display with Java
  1987 applet or isatool browser; data generated automatically via isatool
  1988 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1989 
  1990 * defs may now be conditional; improved rewrite_goals_tac to handle
  1991 conditional equations;
  1992 
  1993 * defs now admits additional type arguments, using TYPE('a) syntax;
  1994 
  1995 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1996 creates a new theory node; implicit merge of thms' signatures is
  1997 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1998 transfer:theory->thm->thm in (rare) cases;
  1999 
  2000 * improved handling of draft signatures / theories; draft thms (and
  2001 ctyps, cterms) are automatically promoted to real ones;
  2002 
  2003 * slightly changed interfaces for oracles: admit many per theory, named
  2004 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2005 
  2006 * print_goals: optional output of const types (set show_consts and
  2007 show_types);
  2008 
  2009 * improved output of warnings (###) and errors (***);
  2010 
  2011 * subgoal_tac displays a warning if the new subgoal has type variables;
  2012 
  2013 * removed old README and Makefiles;
  2014 
  2015 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2016 
  2017 * removed obsolete init_pps and init_database;
  2018 
  2019 * deleted the obsolete tactical STATE, which was declared by
  2020     fun STATE tacfun st = tacfun st st;
  2021 
  2022 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2023 (which abbreviates $HOME);
  2024 
  2025 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2026 use isatool fixseq to adapt your ML programs (this works for fully
  2027 qualified references to the Sequence structure only!);
  2028 
  2029 * use_thy no longer requires writable current directory; it always
  2030 reloads .ML *and* .thy file, if either one is out of date;
  2031 
  2032 
  2033 *** Classical Reasoner ***
  2034 
  2035 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2036 tactics that use classical reasoning to simplify a subgoal without
  2037 splitting it into several subgoals;
  2038 
  2039 * Safe_tac: like safe_tac but uses the default claset;
  2040 
  2041 
  2042 *** Simplifier ***
  2043 
  2044 * added simplification meta rules:
  2045     (asm_)(full_)simplify: simpset -> thm -> thm;
  2046 
  2047 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2048 logics (again);
  2049 
  2050 * added prems argument to simplification procedures;
  2051 
  2052 * HOL, FOL, ZF: added infix function `addsplits':
  2053   instead of `<simpset> setloop (split_tac <thms>)'
  2054   you can simply write `<simpset> addsplits <thms>'
  2055 
  2056 
  2057 *** Syntax ***
  2058 
  2059 * TYPE('a) syntax for type reflection terms;
  2060 
  2061 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2062 
  2063 * pretty printer: changed order of mixfix annotation preference (again!);
  2064 
  2065 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2066 
  2067 
  2068 *** HOL ***
  2069 
  2070 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2071   with `addloop' of the simplifier to faciliate case splitting in premises.
  2072 
  2073 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2074 
  2075 * HOL/Auth: new protocol proofs including some for the Internet
  2076   protocol TLS;
  2077 
  2078 * HOL/Map: new theory of `maps' a la VDM;
  2079 
  2080 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2081 cancelling out common nat summands from =, <, <= (in)equalities, or
  2082 differences; simplification procedures nat_cancel_factor for
  2083 cancelling common factor from =, <, <= (in)equalities over natural
  2084 sums; nat_cancel contains both kinds of procedures, it is installed by
  2085 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2086 
  2087 * HOL/simplifier: terms of the form
  2088   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2089   are rewritten to
  2090   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2091   and those of the form
  2092   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2093   are rewritten to
  2094   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2095 
  2096 * HOL/datatype
  2097   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2098 
  2099   P(t_case f1 ... fn x) =
  2100      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2101         ...
  2102        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2103      )
  2104 
  2105   and a theorem `split_t_case_asm' of the form
  2106 
  2107   P(t_case f1 ... fn x) =
  2108     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2109         ...
  2110        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2111      )
  2112   which can be added to a simpset via `addsplits'. The existing theorems
  2113   expand_list_case and expand_option_case have been renamed to
  2114   split_list_case and split_option_case.
  2115 
  2116 * HOL/Arithmetic:
  2117   - `pred n' is automatically converted to `n-1'.
  2118     Users are strongly encouraged not to use `pred' any longer,
  2119     because it will disappear altogether at some point.
  2120   - Users are strongly encouraged to write "0 < n" rather than
  2121     "n ~= 0". Theorems and proof tools have been modified towards this
  2122     `standard'.
  2123 
  2124 * HOL/Lists:
  2125   the function "set_of_list" has been renamed "set" (and its theorems too);
  2126   the function "nth" now takes its arguments in the reverse order and
  2127   has acquired the infix notation "!" as in "xs!n".
  2128 
  2129 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2130 
  2131 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2132   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2133 
  2134 * HOL/record: extensible records with schematic structural subtyping
  2135 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2136 still lacks various theorems and concrete record syntax;
  2137 
  2138 
  2139 *** HOLCF ***
  2140 
  2141 * removed "axioms" and "generated by" sections;
  2142 
  2143 * replaced "ops" section by extended "consts" section, which is capable of
  2144   handling the continuous function space "->" directly;
  2145 
  2146 * domain package:
  2147   . proves theorems immediately and stores them in the theory,
  2148   . creates hierachical name space,
  2149   . now uses normal mixfix annotations (instead of cinfix...),
  2150   . minor changes to some names and values (for consistency),
  2151   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2152   . separator between mutual domain defs: changed "," to "and",
  2153   . improved handling of sort constraints;  now they have to
  2154     appear on the left-hand side of the equations only;
  2155 
  2156 * fixed LAM <x,y,zs>.b syntax;
  2157 
  2158 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2159 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2160 
  2161 
  2162 *** FOL and ZF ***
  2163 
  2164 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2165   with `addloop' of the simplifier to faciliate case splitting in premises.
  2166 
  2167 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2168 in HOL, they strip ALL and --> from proved theorems;
  2169 
  2170 
  2171 
  2172 New in Isabelle94-8 (May 1997)
  2173 ------------------------------
  2174 
  2175 *** General Changes ***
  2176 
  2177 * new utilities to build / run / maintain Isabelle etc. (in parts
  2178 still somewhat experimental); old Makefiles etc. still functional;
  2179 
  2180 * new 'Isabelle System Manual';
  2181 
  2182 * INSTALL text, together with ./configure and ./build scripts;
  2183 
  2184 * reimplemented type inference for greater efficiency, better error
  2185 messages and clean internal interface;
  2186 
  2187 * prlim command for dealing with lots of subgoals (an easier way of
  2188 setting goals_limit);
  2189 
  2190 
  2191 *** Syntax ***
  2192 
  2193 * supports alternative (named) syntax tables (parser and pretty
  2194 printer); internal interface is provided by add_modesyntax(_i);
  2195 
  2196 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2197 be used in conjunction with the Isabelle symbol font; uses the
  2198 "symbols" syntax table;
  2199 
  2200 * added token_translation interface (may translate name tokens in
  2201 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2202 the current print_mode); IMPORTANT: user print translation functions
  2203 are responsible for marking newly introduced bounds
  2204 (Syntax.mark_boundT);
  2205 
  2206 * token translations for modes "xterm" and "xterm_color" that display
  2207 names in bold, underline etc. or colors (which requires a color
  2208 version of xterm);
  2209 
  2210 * infixes may now be declared with names independent of their syntax;
  2211 
  2212 * added typed_print_translation (like print_translation, but may
  2213 access type of constant);
  2214 
  2215 
  2216 *** Classical Reasoner ***
  2217 
  2218 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2219 some limitations.  Blast_tac...
  2220   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2221   + ignores elimination rules that don't have the correct format
  2222         (the conclusion MUST be a formula variable)
  2223   + ignores types, which can make HOL proofs fail
  2224   + rules must not require higher-order unification, e.g. apply_type in ZF
  2225     [message "Function Var's argument not a bound variable" relates to this]
  2226   + its proof strategy is more general but can actually be slower
  2227 
  2228 * substitution with equality assumptions no longer permutes other
  2229 assumptions;
  2230 
  2231 * minor changes in semantics of addafter (now called addaltern); renamed
  2232 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2233 (and access functions for it);
  2234 
  2235 * improved combination of classical reasoner and simplifier:
  2236   + functions for handling clasimpsets
  2237   + improvement of addss: now the simplifier is called _after_ the
  2238     safe steps.
  2239   + safe variant of addss called addSss: uses safe simplifications
  2240     _during_ the safe steps. It is more complete as it allows multiple
  2241     instantiations of unknowns (e.g. with slow_tac).
  2242 
  2243 *** Simplifier ***
  2244 
  2245 * added interface for simplification procedures (functions that
  2246 produce *proven* rewrite rules on the fly, depending on current
  2247 redex);
  2248 
  2249 * ordering on terms as parameter (used for ordered rewriting);
  2250 
  2251 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2252 
  2253 * the solver is now split into a safe and an unsafe part.
  2254 This should be invisible for the normal user, except that the
  2255 functions setsolver and addsolver have been renamed to setSolver and
  2256 addSolver; added safe_asm_full_simp_tac;
  2257 
  2258 
  2259 *** HOL ***
  2260 
  2261 * a generic induction tactic `induct_tac' which works for all datatypes and
  2262 also for type `nat';
  2263 
  2264 * a generic case distinction tactic `exhaust_tac' which works for all
  2265 datatypes and also for type `nat';
  2266 
  2267 * each datatype comes with a function `size';
  2268 
  2269 * patterns in case expressions allow tuple patterns as arguments to
  2270 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2271 
  2272 * primrec now also works with type nat;
  2273 
  2274 * recdef: a new declaration form, allows general recursive functions to be
  2275 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2276 
  2277 * the constant for negation has been renamed from "not" to "Not" to
  2278 harmonize with FOL, ZF, LK, etc.;
  2279 
  2280 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2281 infinite lists;
  2282 
  2283 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2284 
  2285 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2286 problems in commutative rings, using axiomatic type classes for + and *;
  2287 
  2288 * more examples in HOL/MiniML and HOL/Auth;
  2289 
  2290 * more default rewrite rules for quantifiers, union/intersection;
  2291 
  2292 * a new constant `arbitrary == @x.False';
  2293 
  2294 * HOLCF/IOA replaces old HOL/IOA;
  2295 
  2296 * HOLCF changes: derived all rules and arities
  2297   + axiomatic type classes instead of classes
  2298   + typedef instead of faking type definitions
  2299   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2300   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2301   + eliminated the types void, one, tr
  2302   + use unit lift and bool lift (with translations) instead of one and tr
  2303   + eliminated blift from Lift3.thy (use Def instead of blift)
  2304   all eliminated rules are derived as theorems --> no visible changes ;
  2305 
  2306 
  2307 *** ZF ***
  2308 
  2309 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2310 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2311 as ZF_cs addSIs [equalityI];
  2312 
  2313 
  2314 
  2315 New in Isabelle94-7 (November 96)
  2316 ---------------------------------
  2317 
  2318 * allowing negative levels (as offsets) in prlev and choplev;
  2319 
  2320 * super-linear speedup for large simplifications;
  2321 
  2322 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2323 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2324 FAIL); can suppress it using the command Delsimps (ex_simps @
  2325 all_simps); De Morgan laws are also now included, by default;
  2326 
  2327 * improved printing of ==>  :  ~:
  2328 
  2329 * new object-logic "Sequents" adds linear logic, while replacing LK
  2330 and Modal (thanks to Sara Kalvala);
  2331 
  2332 * HOL/Auth: correctness proofs for authentication protocols;
  2333 
  2334 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2335 examples on HOL/Auth);
  2336 
  2337 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2338 the rewriter and classical reasoner simultaneously;
  2339 
  2340 * function uresult no longer returns theorems in "standard" format;
  2341 regain previous version by: val uresult = standard o uresult;
  2342 
  2343 
  2344 
  2345 New in Isabelle94-6
  2346 -------------------
  2347 
  2348 * oracles -- these establish an interface between Isabelle and trusted
  2349 external reasoners, which may deliver results as theorems;
  2350 
  2351 * proof objects (in particular record all uses of oracles);
  2352 
  2353 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2354 
  2355 * "constdefs" section in theory files;
  2356 
  2357 * "primrec" section (HOL) no longer requires names;
  2358 
  2359 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2360 
  2361 
  2362 
  2363 New in Isabelle94-5
  2364 -------------------
  2365 
  2366 * reduced space requirements;
  2367 
  2368 * automatic HTML generation from theories;
  2369 
  2370 * theory files no longer require "..." (quotes) around most types;
  2371 
  2372 * new examples, including two proofs of the Church-Rosser theorem;
  2373 
  2374 * non-curried (1994) version of HOL is no longer distributed;
  2375 
  2376 
  2377 
  2378 New in Isabelle94-4
  2379 -------------------
  2380 
  2381 * greatly reduced space requirements;
  2382 
  2383 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2384 
  2385 * searchable theorem database (see the section "Retrieving theorems" on
  2386 page 8 of the Reference Manual);
  2387 
  2388 * new examples, including Grabczewski's monumental case study of the
  2389 Axiom of Choice;
  2390 
  2391 * The previous version of HOL renamed to Old_HOL;
  2392 
  2393 * The new version of HOL (previously called CHOL) uses a curried syntax
  2394 for functions.  Application looks like f a b instead of f(a,b);
  2395 
  2396 * Mutually recursive inductive definitions finally work in HOL;
  2397 
  2398 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2399 translates to the operator "split";
  2400 
  2401 
  2402 
  2403 New in Isabelle94-3
  2404 -------------------
  2405 
  2406 * new infix operator, addss, allowing the classical reasoner to
  2407 perform simplification at each step of its search.  Example:
  2408         fast_tac (cs addss ss)
  2409 
  2410 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2411 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2412 look like (a,b) instead of <a,b>;
  2413 
  2414 * PLEASE NOTE: CHOL will eventually replace HOL!
  2415 
  2416 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2417 It translates to the operator "split".  A new theory of integers is available;
  2418 
  2419 * In ZF, integer numerals now denote two's-complement binary integers.
  2420 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2421 
  2422 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2423 of the Axiom of Choice;
  2424 
  2425 
  2426 
  2427 New in Isabelle94-2
  2428 -------------------
  2429 
  2430 * Significantly faster resolution;
  2431 
  2432 * the different sections in a .thy file can now be mixed and repeated
  2433 freely;
  2434 
  2435 * Database of theorems for FOL, HOL and ZF.  New
  2436 commands including qed, qed_goal and bind_thm store theorems in the database.
  2437 
  2438 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2439 a given theory (thms_of), or find out what theory a theorem was proved in
  2440 (theory_of_thm);
  2441 
  2442 * Bugs fixed in the inductive definition and datatype packages;
  2443 
  2444 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2445 and HOL_dup_cs obsolete;
  2446 
  2447 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2448 have been removed;
  2449 
  2450 * Simpler definition of function space in ZF;
  2451 
  2452 * new results about cardinal and ordinal arithmetic in ZF;
  2453 
  2454 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2455 types;
  2456 
  2457 
  2458 $Id$