NEWS
author wenzelm
Tue Nov 13 22:25:59 2001 +0100 (2001-11-13)
changeset 12177 b1c16d685a99
parent 12163 04c98351f9af
child 12210 2f510d8d8291
permissions -rw-r--r--
* ZF: new-style theory commands 'inductive', 'inductive_cases', and
methods 'ind_cases', 'induct_tac', 'case_tac';
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2001 (?? 2001)
     6 -----------------------------
     7 
     8 *** Document preparation ***
     9 
    10 * greatly simplified document preparation setup, including more
    11 graceful interpretation of isatool usedir -i/-d/-D options, and more
    12 instructive isatool mkdir; users should basically be able to get
    13 started with "isatool mkdir Test && isatool make";
    14 
    15 * theory dependency graph may now be incorporated into documents;
    16 isatool usedir -g true will produce session_graph.eps/.pdf for use
    17 with \includegraphics of LaTeX;
    18 
    19 * proper spacing of consecutive markup elements, especially text
    20 blocks after section headings;
    21 
    22 * support bold style (for single symbols only), input syntax is like
    23 this: "\<^bold>\<alpha>" or "\<^bold>A";
    24 
    25 * \<bullet> is now output as bold \cdot by default, which looks much
    26 better in printed text;
    27 
    28 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    29 note that these symbols are currently unavailable in Proof General /
    30 X-Symbol;
    31 
    32 
    33 *** Isar ***
    34 
    35 * improved proof by cases and induction:
    36   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    37   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    38   - moved induct/cases attributes to Pure, methods to Provers;
    39   - generic method setup instantiated for FOL and HOL;
    40 
    41   - 'case' command admits impromptu naming of parameters (such as
    42 "case (Suc n)");
    43 
    44   - 'induct' method divinates rule instantiation from the inductive
    45 claim; no longer requires excessive ?P bindings for proper
    46 instantiation of cases;
    47 
    48   - 'induct' method properly enumerates all possibilities of set/type
    49 rules; as a consequence facts may be also passed through *type* rules
    50 without further ado;
    51 
    52   - 'induct' method now derives symbolic cases from the *rulified*
    53 rule (before it used to rulify cases stemming from the internal
    54 atomized version); this means that the context of a non-atomic
    55 statement becomes is included in the hypothesis, avoiding the slightly
    56 cumbersome show "PROP ?case" form;
    57 
    58   - 'induct' may now use elim-style induction rules without chaining
    59 facts, using ``missing'' premises from the goal state; this allows
    60 rules stemming from inductive sets to be applied in unstructured
    61 scripts, while still benefitting from proper handling of non-atomic
    62 statements; NB: major inductive premises need to be put first, all the
    63 rest of the goal is passed through the induction;
    64 
    65 - 'induct' proper support for mutual induction involving non-atomic
    66 rule statements (uses the new concept of simultaneous goals, see
    67 below);
    68 
    69 * Pure: support multiple simultaneous goal statements, for example
    70 "have a: A and b: B" (same for 'theorem' etc.); being a pure
    71 meta-level mechanism, this acts as if several individual goals had
    72 been stated separately; in particular common proof methods need to be
    73 repeated in order to cover all claims; note that a single elimination
    74 step is *not* sufficient to establish the two conjunctions, so this
    75 fails:
    76 
    77   assume "A & B" then have A and B ..   (*".." fails*)
    78 
    79 better use "obtain" in situations as above; alternative refer to
    80 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
    81 
    82 * Pure: proper integration with ``locales''; unlike the original
    83 version by Florian Kammueller, Isar locales package high-level proof
    84 contexts rather than raw logical ones (e.g. we admit to include
    85 attributes everywhere);
    86 
    87 * Pure: theory goals now support ad-hoc contexts, which are discharged
    88 in the result, as in ``lemma (assumes A and B) K: A .''; syntax
    89 coincides with that of a locale body;
    90 
    91 * Pure: renamed "antecedent" case to "rule_context";
    92 
    93 * Pure: added 'corollary' command;
    94 
    95 * Pure: fixed 'token_translation' command;
    96 
    97 * Pure: removed obsolete 'exported' attribute;
    98 
    99 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   100 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   101 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   102 
   103 * Pure: method 'atomize' presents local goal premises as object-level
   104 statements (atomic meta-level propositions); setup controlled via
   105 rewrite rules declarations of 'atomize' attribute; example
   106 application: 'induct' method with proper rule statements in improper
   107 proof *scripts*;
   108 
   109 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   110 now consider the syntactic context of assumptions, giving a better
   111 chance to get type-inference of the arguments right (this is
   112 especially important for locales);
   113 
   114 * Provers: 'simplified' attribute may refer to explicit rules instead
   115 of full simplifier context; 'iff' attribute handles conditional rules;
   116 
   117 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   118 
   119 * HOL: 'recdef' now fails on unfinished automated proofs, use
   120 "(permissive)" option to recover old behavior;
   121 
   122 * HOL: 'inductive' no longer features separate (collective) attributes
   123 for 'intros' (was found too confusing);
   124 
   125 
   126 
   127 *** HOL ***
   128 
   129 * HOL: moved over to sane numeral syntax; the new policy is as
   130 follows:
   131 
   132   - 0 and 1 are polymorphic constants, which are defined on any
   133   numeric type (nat, int, real etc.);
   134 
   135   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   136   binary representation internally;
   137 
   138   - type nat has special constructor Suc, and generally prefers Suc 0
   139   over 1::nat and Suc (Suc 0) over 2::nat;
   140 
   141 This change may cause significant INCOMPATIBILITIES; here are some
   142 hints on converting existing sources:
   143 
   144   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   145   entities, so expressions involving "-" (unary or binary minus) need
   146   to be spaced properly;
   147 
   148   - existing occurrences of "1" may need to be constraint "1::nat" or
   149   even replaced by Suc 0; similar for old "2";
   150 
   151   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   152 
   153   - remove all special provisions on numerals in proofs;
   154 
   155 * HOL/record:
   156   - removed old "make" and "make_scheme" operations -- INCOMPATIBILITY;
   157   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   158   - provides cases/induct rules for use with corresponding Isar methods;
   159   - new derived operations "make" (for adding fields of current
   160     record), "extend" to promote fixed record to record scheme, and
   161     "truncate" for the reverse; cf. theorems "derived_defs", which are
   162     *not* declared as simp by default;
   163   - internal definitions directly based on a light-weight abstract
   164     theory of product types over typedef rather than datatype;
   165 
   166 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   167 
   168 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   169 (beware of argument permutation!);
   170 
   171 * HOL: linorder_less_split superseded by linorder_cases;
   172 
   173 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   174 to peripheral theory "Hilbert_Choice";
   175 
   176 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   177 in this (rare) case use:
   178 
   179   delSWrapper "split_all_tac"
   180   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   181 
   182 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   183 MAY FAIL;
   184 
   185 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   186 Isabelle's type classes, ^ on functions and relations has too general
   187 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   188 necessary to attach explicit type constraints;
   189 
   190 * HOL: syntax translations now work properly with numerals and records
   191 expressions;
   192 
   193 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   194 Florian Kammüller;
   195 
   196 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   197 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   198 renamed "Product_Type.unit";
   199 
   200 
   201 *** HOLCF ***
   202 
   203 * proper rep_datatype lift (see theory Lift); use plain induct_tac
   204 instead of former lift.induct_tac; always use UU instead of Undef;
   205 
   206 * 'domain' package adapted to new-style theories, e.g. see
   207 HOLCF/ex/Dnat.thy;
   208 
   209 
   210 *** ZF ***
   211 
   212 * ZF: new-style theory commands 'inductive', 'inductive_cases', and
   213 methods 'ind_cases', 'induct_tac', 'case_tac';
   214 
   215 * ZF: the integer library now covers quotients and remainders, with
   216 many laws relating division to addition, multiplication, etc.;
   217 
   218 * ZF/Induct: new directory for examples of inductive definitions,
   219 including theory Multiset for multiset orderings;
   220 
   221 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   222 typeless version of the formalism;
   223 
   224 
   225 *** General ***
   226 
   227 * kernel: meta-level proof terms (by Stefan Berghofer), see also ref
   228 manual;
   229 
   230 * Pure/axclass: removed obsolete ML interface goal_subclass/goal_arity;
   231 
   232 * classical: renamed addaltern to addafter, addSaltern to addSafter;
   233 
   234 * clasimp: ``iff'' declarations now handle conditional rules as well;
   235 
   236 * syntax: new token syntax "num" for plain numerals (without "#" of
   237 "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now separate
   238 tokens, so expressions involving minus need to be spaced properly;
   239 
   240 * syntax: support non-oriented infixes;
   241 
   242 * syntax: print modes "type_brackets" and "no_type_brackets" control
   243 output of nested => (types); the default behavior is "type_brackets";
   244 
   245 * syntax: builtin parse translation for "_constify" turns valued
   246 tokens into AST constants;
   247 
   248 * system: refrain from any attempt at filtering input streams; no
   249 longer support ``8bit'' encoding of old isabelle font, instead proper
   250 iso-latin characters may now be used;
   251 
   252 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   253 
   254 * system: Proof General keywords specification is now part of the
   255 Isabelle distribution (see etc/isar-keywords.el);
   256 
   257 * system: smart selection of Isabelle process versus Isabelle
   258 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   259 run both "isabelle" and "Isabelle" even if file names are badly
   260 damaged (executable inspects the case of the first letter of its own
   261 name); added separate "isabelle-process" and "isabelle-interface";
   262 
   263 
   264 
   265 New in Isabelle99-2 (February 2001)
   266 -----------------------------------
   267 
   268 *** Overview of INCOMPATIBILITIES ***
   269 
   270 * HOL: please note that theories in the Library and elsewhere often use the
   271 new-style (Isar) format; to refer to their theorems in an ML script you must
   272 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   273 
   274 * HOL: inductive package no longer splits induction rule aggressively,
   275 but only as far as specified by the introductions given; the old
   276 format may be recovered via ML function complete_split_rule or attribute
   277 'split_rule (complete)';
   278 
   279 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   280 gfp_Tarski to gfp_unfold;
   281 
   282 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   283 
   284 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   285 relation); infix "^^" has been renamed "``"; infix "``" has been
   286 renamed "`"; "univalent" has been renamed "single_valued";
   287 
   288 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   289 operation;
   290 
   291 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   292 
   293 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   294 
   295 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   296 consequence, it is no longer monotonic wrt. the local goal context
   297 (which is now passed through the inductive cases);
   298 
   299 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   300 \<gg> to \<ggreater>;
   301 
   302 
   303 *** Document preparation ***
   304 
   305 * \isabellestyle{NAME} selects version of Isabelle output (currently
   306 available: are "it" for near math-mode best-style output, "sl" for
   307 slanted text style, and "tt" for plain type-writer; if no
   308 \isabellestyle command is given, output is according to slanted
   309 type-writer);
   310 
   311 * support sub/super scripts (for single symbols only), input syntax is
   312 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   313 
   314 * some more standard symbols; see Appendix A of the system manual for
   315 the complete list of symbols defined in isabellesym.sty;
   316 
   317 * improved isabelle style files; more abstract symbol implementation
   318 (should now use \isamath{...} and \isatext{...} in custom symbol
   319 definitions);
   320 
   321 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   322 state; Note that presentation of goal states does not conform to
   323 actual human-readable proof documents.  Please do not include goal
   324 states into document output unless you really know what you are doing!
   325 
   326 * proper indentation of antiquoted output with proportional LaTeX
   327 fonts;
   328 
   329 * no_document ML operator temporarily disables LaTeX document
   330 generation;
   331 
   332 * isatool unsymbolize tunes sources for plain ASCII communication;
   333 
   334 
   335 *** Isar ***
   336 
   337 * Pure: Isar now suffers initial goal statements to contain unbound
   338 schematic variables (this does not conform to actual readable proof
   339 documents, due to unpredictable outcome and non-compositional proof
   340 checking); users who know what they are doing may use schematic goals
   341 for Prolog-style synthesis of proven results;
   342 
   343 * Pure: assumption method (an implicit finishing) now handles actual
   344 rules as well;
   345 
   346 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   347 initial goal, declare "that" only as Pure intro (only for single
   348 steps); the "that" rule assumption may now be involved in implicit
   349 finishing, thus ".." becomes a feasible for trivial obtains;
   350 
   351 * Pure: default proof step now includes 'intro_classes'; thus trivial
   352 instance proofs may be performed by "..";
   353 
   354 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   355 statements as well;
   356 
   357 * Pure: more robust selection of calculational rules;
   358 
   359 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   360 rule (as well as the assumption rule);
   361 
   362 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   363 lemmas, using the graph browser tool;
   364 
   365 * Pure: predict failure of "show" in interactive mode;
   366 
   367 * Pure: 'thms_containing' now takes actual terms as arguments;
   368 
   369 * HOL: improved method 'induct' --- now handles non-atomic goals
   370 (potential INCOMPATIBILITY); tuned error handling;
   371 
   372 * HOL: cases and induct rules now provide explicit hints about the
   373 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   374 any remaining facts are inserted into the goal verbatim;
   375 
   376 * HOL: local contexts (aka cases) may now contain term bindings as
   377 well; the 'cases' and 'induct' methods new provide a ?case binding for
   378 the result to be shown in each case;
   379 
   380 * HOL: added 'recdef_tc' command;
   381 
   382 * isatool convert assists in eliminating legacy ML scripts;
   383 
   384 
   385 *** HOL ***
   386 
   387 * HOL/Library: a collection of generic theories to be used together
   388 with main HOL; the theory loader path already includes this directory
   389 by default; the following existing theories have been moved here:
   390 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   391 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   392 
   393 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   394 modelling and verification task performed in Isabelle/HOL +
   395 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   396 
   397 * HOL/Algebra: special summation operator SUM no longer exists, it has
   398 been replaced by setsum; infix 'assoc' now has priority 50 (like
   399 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   400 'domain', this makes the theory consistent with mathematical
   401 literature;
   402 
   403 * HOL basics: added overloaded operations "inverse" and "divide"
   404 (infix "/"), syntax for generic "abs" operation, generic summation
   405 operator \<Sum>;
   406 
   407 * HOL/typedef: simplified package, provide more useful rules (see also
   408 HOL/subset.thy);
   409 
   410 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   411 now expressed as a proper nested rule (old-style tactic scripts may
   412 require atomize_strip_tac to cope with non-atomic premises);
   413 
   414 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   415 to "split_conv" (old name still available for compatibility);
   416 
   417 * HOL: improved concrete syntax for strings (e.g. allows translation
   418 rules with string literals);
   419 
   420 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   421 and Fleuriot's mechanization of analysis;
   422 
   423 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   424 
   425 
   426 *** CTT ***
   427 
   428 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   429 "lam" is displayed as TWO lambda-symbols
   430 
   431 * CTT: theory Main now available, containing everything (that is, Bool
   432 and Arith);
   433 
   434 
   435 *** General ***
   436 
   437 * Pure: the Simplifier has been implemented properly as a derived rule
   438 outside of the actual kernel (at last!); the overall performance
   439 penalty in practical applications is about 50%, while reliability of
   440 the Isabelle inference kernel has been greatly improved;
   441 
   442 * print modes "brackets" and "no_brackets" control output of nested =>
   443 (types) and ==> (props); the default behaviour is "brackets";
   444 
   445 * Provers: fast_tac (and friends) now handle actual object-logic rules
   446 as assumptions as well;
   447 
   448 * system: support Poly/ML 4.0;
   449 
   450 * system: isatool install handles KDE version 1 or 2;
   451 
   452 
   453 
   454 New in Isabelle99-1 (October 2000)
   455 ----------------------------------
   456 
   457 *** Overview of INCOMPATIBILITIES ***
   458 
   459 * HOL: simplification of natural numbers is much changed; to partly
   460 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   461 issue the following ML commands:
   462 
   463   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   464   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   465 
   466 * HOL: simplification no longer dives into case-expressions; this is
   467 controlled by "t.weak_case_cong" for each datatype t;
   468 
   469 * HOL: nat_less_induct renamed to less_induct;
   470 
   471 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   472 fixsome to patch .thy and .ML sources automatically;
   473 
   474   select_equality  -> some_equality
   475   select_eq_Ex     -> some_eq_ex
   476   selectI2EX       -> someI2_ex
   477   selectI2         -> someI2
   478   selectI          -> someI
   479   select1_equality -> some1_equality
   480   Eps_sym_eq       -> some_sym_eq_trivial
   481   Eps_eq           -> some_eq_trivial
   482 
   483 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   484 
   485 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   486 instead);
   487 
   488 * HOL: the recursion equations generated by 'recdef' are now called
   489 f.simps instead of f.rules;
   490 
   491 * HOL: qed_spec_mp now also handles bounded ALL as well;
   492 
   493 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   494 sometimes be needed;
   495 
   496 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   497 
   498 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   499 
   500 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   501 product is now "<*>" instead of "Times"; the lexicographic product is
   502 now "<*lex*>" instead of "**";
   503 
   504 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   505 of main HOL, but was unused); better use HOL's datatype package;
   506 
   507 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   508 the old syntax may be recovered as follows:
   509 
   510   syntax (symbols)
   511     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   512       (infixl "\\<oplus>" 100)
   513 
   514 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   515 
   516 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   517 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   518 internally;
   519 
   520 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   521 changed from A/r to A//r;
   522 
   523 * ZF: new treatment of arithmetic (nat & int) may break some old
   524 proofs;
   525 
   526 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   527 rulify -> rule_format, elimify -> elim_format, ...);
   528 
   529 * Isar/Provers: intro/elim/dest attributes changed; renamed
   530 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   531 should have to change intro!! to intro? only); replaced "delrule" by
   532 "rule del";
   533 
   534 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   535 
   536 * Provers: strengthened force_tac by using new first_best_tac;
   537 
   538 * LaTeX document preparation: several changes of isabelle.sty (see
   539 lib/texinputs);
   540 
   541 
   542 *** Document preparation ***
   543 
   544 * formal comments (text blocks etc.) in new-style theories may now
   545 contain antiquotations of thm/prop/term/typ/text to be presented
   546 according to latex print mode; concrete syntax is like this:
   547 @{term[show_types] "f(x) = a + x"};
   548 
   549 * isatool mkdir provides easy setup of Isabelle session directories,
   550 including proper document sources;
   551 
   552 * generated LaTeX sources are now deleted after successful run
   553 (isatool document -c); may retain a copy somewhere else via -D option
   554 of isatool usedir;
   555 
   556 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   557 style files, achieving self-contained LaTeX sources and simplifying
   558 LaTeX debugging;
   559 
   560 * old-style theories now produce (crude) LaTeX output as well;
   561 
   562 * browser info session directories are now self-contained (may be put
   563 on WWW server seperately); improved graphs of nested sessions; removed
   564 graph for 'all sessions';
   565 
   566 * several improvements in isabelle style files; \isabellestyle{it}
   567 produces fake math mode output; \isamarkupheader is now \section by
   568 default; see lib/texinputs/isabelle.sty etc.;
   569 
   570 
   571 *** Isar ***
   572 
   573 * Isar/Pure: local results and corresponding term bindings are now
   574 subject to Hindley-Milner polymorphism (similar to ML); this
   575 accommodates incremental type-inference very nicely;
   576 
   577 * Isar/Pure: new derived language element 'obtain' supports
   578 generalized existence reasoning;
   579 
   580 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   581 support accumulation of results, without applying any rules yet;
   582 useful to collect intermediate results without explicit name
   583 references, and for use with transitivity rules with more than 2
   584 premises;
   585 
   586 * Isar/Pure: scalable support for case-analysis type proofs: new
   587 'case' language element refers to local contexts symbolically, as
   588 produced by certain proof methods; internally, case names are attached
   589 to theorems as "tags";
   590 
   591 * Isar/Pure: theory command 'hide' removes declarations from
   592 class/type/const name spaces;
   593 
   594 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   595 indicate potential overloading;
   596 
   597 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   598 
   599 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   600 "{a,b,c}" instead of {a,b,c};
   601 
   602 * Isar/Pure now provides its own version of intro/elim/dest
   603 attributes; useful for building new logics, but beware of confusion
   604 with the version in Provers/classical;
   605 
   606 * Isar/Pure: the local context of (non-atomic) goals is provided via
   607 case name 'antecedent';
   608 
   609 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   610 to the current context is now done automatically);
   611 
   612 * Isar/Pure: theory command 'method_setup' provides a simple interface
   613 for definining proof methods in ML;
   614 
   615 * Isar/Provers: intro/elim/dest attributes changed; renamed
   616 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   617 most cases, one should have to change intro!! to intro? only);
   618 replaced "delrule" by "rule del";
   619 
   620 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   621 'symmetric' attribute (the latter supercedes [RS sym]);
   622 
   623 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   624 method modifier); 'simp' method: 'only:' modifier removes loopers as
   625 well (including splits);
   626 
   627 * Isar/Provers: Simplifier and Classical methods now support all kind
   628 of modifiers used in the past, including 'cong', 'iff', etc.
   629 
   630 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   631 of Simplifier and Classical reasoner);
   632 
   633 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   634 now support named cases; major packages (inductive, datatype, primrec,
   635 recdef) support case names and properly name parameters;
   636 
   637 * Isar/HOL: new transitivity rules for substitution in inequalities --
   638 monotonicity conditions are extracted to be proven at end of
   639 calculations;
   640 
   641 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   642 method anyway;
   643 
   644 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   645 split_if split_if_asm; datatype package provides theorems foo.splits =
   646 foo.split foo.split_asm for each datatype;
   647 
   648 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   649 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   650 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   651 use "(cases (simplified))" method in proper proof texts);
   652 
   653 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   654 
   655 * Isar: names of theorems etc. may be natural numbers as well;
   656 
   657 * Isar: 'pr' command: optional arguments for goals_limit and
   658 ProofContext.prems_limit; no longer prints theory contexts, but only
   659 proof states;
   660 
   661 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   662 additional print modes to be specified; e.g. "pr(latex)" will print
   663 proof state according to the Isabelle LaTeX style;
   664 
   665 * Isar: improved support for emulating tactic scripts, including proof
   666 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   667 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   668 (for HOL datatypes);
   669 
   670 * Isar: simplified (more robust) goal selection of proof methods: 1st
   671 goal, all goals, or explicit goal specifier (tactic emulation); thus
   672 'proof method scripts' have to be in depth-first order;
   673 
   674 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   675 
   676 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   677 should instead use individual commands for printing items
   678 (print_commands, print_methods etc.);
   679 
   680 * Isar: added 'nothing' --- the empty list of theorems;
   681 
   682 
   683 *** HOL ***
   684 
   685 * HOL/MicroJava: formalization of a fragment of Java, together with a
   686 corresponding virtual machine and a specification of its bytecode
   687 verifier and a lightweight bytecode verifier, including proofs of
   688 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   689 Cornelia Pusch (see also the homepage of project Bali at
   690 http://isabelle.in.tum.de/Bali/);
   691 
   692 * HOL/Algebra: new theory of rings and univariate polynomials, by
   693 Clemens Ballarin;
   694 
   695 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   696 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   697 Rasmussen;
   698 
   699 * HOL/Lattice: fundamental concepts of lattice theory and order
   700 structures, including duals, properties of bounds versus algebraic
   701 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   702 Theorem for complete lattices etc.; may also serve as a demonstration
   703 for abstract algebraic reasoning using axiomatic type classes, and
   704 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   705 
   706 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   707 von Oheimb;
   708 
   709 * HOL/IMPP: extension of IMP with local variables and mutually
   710 recursive procedures, by David von Oheimb;
   711 
   712 * HOL/Lambda: converted into new-style theory and document;
   713 
   714 * HOL/ex/Multiquote: example of multiple nested quotations and
   715 anti-quotations -- basically a generalized version of de-Bruijn
   716 representation; very useful in avoiding lifting of operations;
   717 
   718 * HOL/record: added general record equality rule to simpset; fixed
   719 select-update simplification procedure to handle extended records as
   720 well; admit "r" as field name;
   721 
   722 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   723 other numeric types and also as the identity of groups, rings, etc.;
   724 
   725 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   726 Types nat and int belong to this axclass;
   727 
   728 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   729    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   730    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   731   two terms #m*u and #n*u are replaced by #(m+n)*u
   732     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   733   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   734     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   735 
   736 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   737 powerful prover for predicate logic but knows nothing of clasets; see
   738 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   739 
   740 * HOL: new version of "case_tac" subsumes both boolean case split and
   741 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   742 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   743 
   744 * HOL: simplification no longer dives into case-expressions: only the
   745 selector expression is simplified, but not the remaining arms; to
   746 enable full simplification of case-expressions for datatype t, you may
   747 remove t.weak_case_cong from the simpset, either globally (Delcongs
   748 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   749 
   750 * HOL/recdef: the recursion equations generated by 'recdef' for
   751 function 'f' are now called f.simps instead of f.rules; if all
   752 termination conditions are proved automatically, these simplification
   753 rules are added to the simpset, as in primrec; rules may be named
   754 individually as well, resulting in a separate list of theorems for
   755 each equation;
   756 
   757 * HOL/While is a new theory that provides a while-combinator. It
   758 permits the definition of tail-recursive functions without the
   759 provision of a termination measure. The latter is necessary once the
   760 invariant proof rule for while is applied.
   761 
   762 * HOL: new (overloaded) notation for the set of elements below/above
   763 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   764 
   765 * HOL: theorems impI, allI, ballI bound as "strip";
   766 
   767 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   768 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   769 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   770 
   771 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   772 
   773 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   774 main HOL, but was unused);
   775 
   776 * HOL: fewer consts declared as global (e.g. have to refer to
   777 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   778 
   779 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   780 in case of overlap with user translations (e.g. judgements over
   781 tuples); (note that the underlying logical represenation is still
   782 bogus);
   783 
   784 
   785 *** ZF ***
   786 
   787 * ZF: simplification automatically cancels common terms in arithmetic
   788 expressions over nat and int;
   789 
   790 * ZF: new treatment of nat to minimize type-checking: all operators
   791 coerce their operands to a natural number using the function natify,
   792 making the algebraic laws unconditional;
   793 
   794 * ZF: as above, for int: operators coerce their operands to an integer
   795 using the function intify;
   796 
   797 * ZF: the integer library now contains many of the usual laws for the
   798 orderings, including $<=, and monotonicity laws for $+ and $*;
   799 
   800 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   801 simplification;
   802 
   803 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   804 to the simplifier and classical reasoner simultaneously;
   805 
   806 
   807 *** General ***
   808 
   809 * Provers: blast_tac now handles actual object-logic rules as
   810 assumptions; note that auto_tac uses blast_tac internally as well;
   811 
   812 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   813 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   814 
   815 * Provers: delrules now handles destruct rules as well (no longer need
   816 explicit make_elim);
   817 
   818 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   819   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   820 use instead the strong form,
   821   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   822 in HOL, FOL and ZF the function cla_make_elim will create such rules
   823 from destruct-rules;
   824 
   825 * Provers: Simplifier.easy_setup provides a fast path to basic
   826 Simplifier setup for new object-logics;
   827 
   828 * Pure: AST translation rules no longer require constant head on LHS;
   829 
   830 * Pure: improved name spaces: ambiguous output is qualified; support
   831 for hiding of names;
   832 
   833 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   834 XSYMBOL_HOME; no longer need to do manual configuration in most
   835 situations;
   836 
   837 * system: compression of ML heaps images may now be controlled via -c
   838 option of isabelle and isatool usedir (currently only observed by
   839 Poly/ML);
   840 
   841 * system: isatool installfonts may handle X-Symbol fonts as well (very
   842 useful for remote X11);
   843 
   844 * system: provide TAGS file for Isabelle sources;
   845 
   846 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   847 order;
   848 
   849 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   850 timing flag supersedes proof_timing and Toplevel.trace;
   851 
   852 * ML: new combinators |>> and |>>> for incremental transformations
   853 with secondary results (e.g. certain theory extensions):
   854 
   855 * ML: PureThy.add_defs gets additional argument to indicate potential
   856 overloading (usually false);
   857 
   858 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   859 results;
   860 
   861 
   862 
   863 New in Isabelle99 (October 1999)
   864 --------------------------------
   865 
   866 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   867 
   868 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   869 are no longer simplified.  (This allows the simplifier to unfold recursive
   870 functional programs.)  To restore the old behaviour, declare
   871 
   872     Delcongs [if_weak_cong];
   873 
   874 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   875 complement;
   876 
   877 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   878 
   879 * HOL/datatype: mutual_induct_tac no longer exists --
   880   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   881 
   882 * HOL/typedef: fixed type inference for representing set; type
   883 arguments now have to occur explicitly on the rhs as type constraints;
   884 
   885 * ZF: The con_defs part of an inductive definition may no longer refer
   886 to constants declared in the same theory;
   887 
   888 * HOL, ZF: the function mk_cases, generated by the inductive
   889 definition package, has lost an argument.  To simplify its result, it
   890 uses the default simpset instead of a supplied list of theorems.
   891 
   892 * HOL/List: the constructors of type list are now Nil and Cons;
   893 
   894 * Simplifier: the type of the infix ML functions
   895         setSSolver addSSolver setSolver addSolver
   896 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   897 for packaging solvers. A solver is created via
   898         mk_solver: string -> (thm list -> int -> tactic) -> solver
   899 where the string argument is only a comment.
   900 
   901 
   902 *** Proof tools ***
   903 
   904 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   905 decision procedure for linear arithmetic. Currently it is used for
   906 types `nat', `int', and `real' in HOL (see below); it can, should and
   907 will be instantiated for other types and logics as well.
   908 
   909 * The simplifier now accepts rewrite rules with flexible heads, eg
   910      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   911   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   912   matching.
   913 
   914 
   915 *** General ***
   916 
   917 * New Isabelle/Isar subsystem provides an alternative to traditional
   918 tactical theorem proving; together with the ProofGeneral/isar user
   919 interface it offers an interactive environment for developing human
   920 readable proof documents (Isar == Intelligible semi-automated
   921 reasoning); for further information see isatool doc isar-ref,
   922 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   923 
   924 * improved and simplified presentation of theories: better HTML markup
   925 (including colors), graph views in several sizes; isatool usedir now
   926 provides a proper interface for user theories (via -P option); actual
   927 document preparation based on (PDF)LaTeX is available as well (for
   928 new-style theories only); see isatool doc system for more information;
   929 
   930 * native support for Proof General, both for classic Isabelle and
   931 Isabelle/Isar;
   932 
   933 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   934 using the graph browser tool;
   935 
   936 * Isabelle manuals now also available as PDF;
   937 
   938 * theory loader rewritten from scratch (may not be fully
   939 bug-compatible); old loadpath variable has been replaced by show_path,
   940 add_path, del_path, reset_path functions; new operations such as
   941 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   942 isatool doc ref);
   943 
   944 * improved isatool install: option -k creates KDE application icon,
   945 option -p DIR installs standalone binaries;
   946 
   947 * added ML_PLATFORM setting (useful for cross-platform installations);
   948 more robust handling of platform specific ML images for SML/NJ;
   949 
   950 * the settings environment is now statically scoped, i.e. it is never
   951 created again in sub-processes invoked from isabelle, isatool, or
   952 Isabelle;
   953 
   954 * path element specification '~~' refers to '$ISABELLE_HOME';
   955 
   956 * in locales, the "assumes" and "defines" parts may be omitted if
   957 empty;
   958 
   959 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   960 long arrows);
   961 
   962 * new print_mode "HTML";
   963 
   964 * new flag show_tags controls display of tags of theorems (which are
   965 basically just comments that may be attached by some tools);
   966 
   967 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   968 mode and goal output format:
   969 
   970 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   971 244c244
   972 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   973 ---
   974 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   975 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   976 181c181
   977 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   978 ---
   979 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   980 
   981 * function bind_thms stores lists of theorems (cf. bind_thm);
   982 
   983 * new shorthand tactics ftac, eatac, datac, fatac;
   984 
   985 * qed (and friends) now accept "" as result name; in that case the
   986 theorem is not stored, but proper checks and presentation of the
   987 result still apply;
   988 
   989 * theorem database now also indexes constants "Trueprop", "all",
   990 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   991 
   992 
   993 *** HOL ***
   994 
   995 ** HOL arithmetic **
   996 
   997 * There are now decision procedures for linear arithmetic over nat and
   998 int:
   999 
  1000 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1001 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1002 are treated as atomic; subformulae not involving type `nat' or `int'
  1003 are ignored; quantified subformulae are ignored unless they are
  1004 positive universal or negative existential. The tactic has to be
  1005 invoked by hand and can be a little bit slow. In particular, the
  1006 running time is exponential in the number of occurrences of `min' and
  1007 `max', and `-' on `nat'.
  1008 
  1009 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1010 (negated) (in)equalities among the premises and the conclusion into
  1011 account (i.e. no compound formulae) and does not know about `min' and
  1012 `max', and `-' on `nat'. It is fast and is used automatically by the
  1013 simplifier.
  1014 
  1015 NB: At the moment, these decision procedures do not cope with mixed
  1016 nat/int formulae where the two parts interact, such as `m < n ==>
  1017 int(m) < int(n)'.
  1018 
  1019 * HOL/Numeral provides a generic theory of numerals (encoded
  1020 efficiently as bit strings); setup for types nat/int/real is in place;
  1021 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1022 int, existing theories and proof scripts may require a few additional
  1023 type constraints;
  1024 
  1025 * integer division and remainder can now be performed on constant
  1026 arguments;
  1027 
  1028 * many properties of integer multiplication, division and remainder
  1029 are now available;
  1030 
  1031 * An interface to the Stanford Validity Checker (SVC) is available through the
  1032 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1033 are proved automatically.  SVC must be installed separately, and its results
  1034 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1035 invocation of the underlying oracle).  For SVC see
  1036   http://verify.stanford.edu/SVC
  1037 
  1038 * IsaMakefile: the HOL-Real target now builds an actual image;
  1039 
  1040 
  1041 ** HOL misc **
  1042 
  1043 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1044 (in Isabelle/Isar) -- by Gertrud Bauer;
  1045 
  1046 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1047 analysis for assembly languages with subtypes;
  1048 
  1049 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1050 -- avoids syntactic ambiguities and treats state, transition, and
  1051 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1052 changed syntax and (many) tactics;
  1053 
  1054 * HOL/inductive: Now also handles more general introduction rules such
  1055   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1056   theorems are now maintained within the theory (maintained via the
  1057   "mono" attribute);
  1058 
  1059 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1060   (using function types) such as
  1061 
  1062   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1063 
  1064 * HOL/record: record_simproc (part of the default simpset) takes care
  1065 of selectors applied to updated records; record_split_tac is no longer
  1066 part of the default claset; update_defs may now be removed from the
  1067 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1068 
  1069   claset_ref () := claset() addSWrapper record_split_wrapper;
  1070   Delsimprocs [record_simproc]
  1071 
  1072 * HOL/typedef: fixed type inference for representing set; type
  1073 arguments now have to occur explicitly on the rhs as type constraints;
  1074 
  1075 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1076 names rather than an ML expression;
  1077 
  1078 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1079 supplied later.  Program schemes can be defined, such as
  1080     "While B C s = (if B s then While B C (C s) else s)"
  1081 where the well-founded relation can be chosen after B and C have been given.
  1082 
  1083 * HOL/List: the constructors of type list are now Nil and Cons;
  1084 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1085 course, ML tools referring to List.list.op # etc. have to be adapted;
  1086 
  1087 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1088 disabled by default; run isabelle with option -m HOL to get back to
  1089 the original Gordon/HOL-style output;
  1090 
  1091 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1092 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1093 
  1094 * HOL basic syntax simplified (more orthogonal): all variants of
  1095 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1096 Eps operator is provided as well: "SOME x. P[x]";
  1097 
  1098 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1099 
  1100 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1101 thus available for user theories;
  1102 
  1103 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1104 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1105 time;
  1106 
  1107 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1108 several times and then mp;
  1109 
  1110 
  1111 *** LK ***
  1112 
  1113 * the notation <<...>> is now available as a notation for sequences of
  1114 formulas;
  1115 
  1116 * the simplifier is now installed
  1117 
  1118 * the axiom system has been generalized (thanks to Soren Heilmann)
  1119 
  1120 * the classical reasoner now has a default rule database
  1121 
  1122 
  1123 *** ZF ***
  1124 
  1125 * new primrec section allows primitive recursive functions to be given
  1126 directly (as in HOL) over datatypes and the natural numbers;
  1127 
  1128 * new tactics induct_tac and exhaust_tac for induction (or case
  1129 analysis) over datatypes and the natural numbers;
  1130 
  1131 * the datatype declaration of type T now defines the recursor T_rec;
  1132 
  1133 * simplification automatically does freeness reasoning for datatype
  1134 constructors;
  1135 
  1136 * automatic type-inference, with AddTCs command to insert new
  1137 type-checking rules;
  1138 
  1139 * datatype introduction rules are now added as Safe Introduction rules
  1140 to the claset;
  1141 
  1142 * the syntax "if P then x else y" is now available in addition to
  1143 if(P,x,y);
  1144 
  1145 
  1146 *** Internal programming interfaces ***
  1147 
  1148 * tuned simplifier trace output; new flag debug_simp;
  1149 
  1150 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1151 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1152 
  1153 * AxClass.axclass_tac lost the theory argument;
  1154 
  1155 * tuned current_goals_markers semantics: begin / end goal avoids
  1156 printing empty lines;
  1157 
  1158 * removed prs and prs_fn hook, which was broken because it did not
  1159 include \n in its semantics, forcing writeln to add one
  1160 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1161 string -> unit if you really want to output text without newline;
  1162 
  1163 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1164 plain output, interface builders may have to enable 'isabelle_font'
  1165 mode to get Isabelle font glyphs as before;
  1166 
  1167 * refined token_translation interface; INCOMPATIBILITY: output length
  1168 now of type real instead of int;
  1169 
  1170 * theory loader actions may be traced via new ThyInfo.add_hook
  1171 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1172 your own database of information attached to *whole* theories -- as
  1173 opposed to intra-theory data slots offered via TheoryDataFun;
  1174 
  1175 * proper handling of dangling sort hypotheses (at last!);
  1176 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1177 extra sort hypotheses that can be witnessed from the type signature;
  1178 the force_strip_shyps flag is gone, any remaining shyps are simply
  1179 left in the theorem (with a warning issued by strip_shyps_warning);
  1180 
  1181 
  1182 
  1183 New in Isabelle98-1 (October 1998)
  1184 ----------------------------------
  1185 
  1186 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1187 
  1188 * several changes of automated proof tools;
  1189 
  1190 * HOL: major changes to the inductive and datatype packages, including
  1191 some minor incompatibilities of theory syntax;
  1192 
  1193 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1194 called `inj_on';
  1195 
  1196 * HOL: removed duplicate thms in Arith:
  1197   less_imp_add_less  should be replaced by  trans_less_add1
  1198   le_imp_add_le      should be replaced by  trans_le_add1
  1199 
  1200 * HOL: unary minus is now overloaded (new type constraints may be
  1201 required);
  1202 
  1203 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1204 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1205 now taken as an integer constant.
  1206 
  1207 * Pure: ML function 'theory_of' renamed to 'theory';
  1208 
  1209 
  1210 *** Proof tools ***
  1211 
  1212 * Simplifier:
  1213   1. Asm_full_simp_tac is now more aggressive.
  1214      1. It will sometimes reorient premises if that increases their power to
  1215         simplify.
  1216      2. It does no longer proceed strictly from left to right but may also
  1217         rotate premises to achieve further simplification.
  1218      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1219      old Asm_full_simp_tac in that it does not rotate premises.
  1220   2. The simplifier now knows a little bit about nat-arithmetic.
  1221 
  1222 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1223 allows for selected deletion of wrappers, by introduction of names for
  1224 wrapper functionals.  This implies that addbefore, addSbefore,
  1225 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1226 and that adding two tactics with the same name overwrites the first
  1227 one (emitting a warning).
  1228   type wrapper = (int -> tactic) -> (int -> tactic)
  1229   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1230   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1231   delWrapper, delSWrapper: claset *  string            -> claset
  1232   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1233 
  1234 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1235 semantics; addbefore now affects only the unsafe part of step_tac
  1236 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1237 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1238 by Force_tac;
  1239 
  1240 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1241 compWrapper; added safe wrapper (and access functions for it);
  1242 
  1243 * HOL/split_all_tac is now much faster and fails if there is nothing
  1244 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1245 and the names of the automatically generated variables have changed.
  1246 split_all_tac has moved within claset() from unsafe wrappers to safe
  1247 wrappers, which means that !!-bound variables are split much more
  1248 aggressively, and safe_tac and clarify_tac now split such variables.
  1249 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1250 Note: the same holds for record_split_tac, which does the job of
  1251 split_all_tac for record fields.
  1252 
  1253 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1254 permanently to the default simpset using Addsplits just like
  1255 Addsimps. They can be removed via Delsplits just like
  1256 Delsimps. Lower-case versions are also available.
  1257 
  1258 * HOL/Simplifier: The rule split_if is now part of the default
  1259 simpset. This means that the simplifier will eliminate all occurrences
  1260 of if-then-else in the conclusion of a goal. To prevent this, you can
  1261 either remove split_if completely from the default simpset by
  1262 `Delsplits [split_if]' or remove it in a specific call of the
  1263 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1264 other case splitting rules to/from the default simpset: every datatype
  1265 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1266 t is the name of the datatype).
  1267 
  1268 * Classical reasoner / Simplifier combination: new force_tac (and
  1269 derivatives Force_tac, force) combines rewriting and classical
  1270 reasoning (and whatever other tools) similarly to auto_tac, but is
  1271 aimed to solve the given subgoal completely.
  1272 
  1273 
  1274 *** General ***
  1275 
  1276 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1277 and `goalw': the theory is no longer needed as an explicit argument -
  1278 the current theory context is used; assumptions are no longer returned
  1279 at the ML-level unless one of them starts with ==> or !!; it is
  1280 recommended to convert to these new commands using isatool fixgoal
  1281 (backup your sources first!);
  1282 
  1283 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1284 the current theory context, and 'theory' to lookup stored theories;
  1285 
  1286 * new theory section 'locale' for declaring constants, assumptions and
  1287 definitions that have local scope;
  1288 
  1289 * new theory section 'nonterminals' for purely syntactic types;
  1290 
  1291 * new theory section 'setup' for generic ML setup functions
  1292 (e.g. package initialization);
  1293 
  1294 * the distribution now includes Isabelle icons: see
  1295 lib/logo/isabelle-{small,tiny}.xpm;
  1296 
  1297 * isatool install - install binaries with absolute references to
  1298 ISABELLE_HOME/bin;
  1299 
  1300 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1301 
  1302 * print mode 'emacs' reserved for Isamode;
  1303 
  1304 * support multiple print (ast) translations per constant name;
  1305 
  1306 * theorems involving oracles are now printed with a suffixed [!];
  1307 
  1308 
  1309 *** HOL ***
  1310 
  1311 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1312 
  1313 * HOL/inductive package reorganized and improved: now supports mutual
  1314 definitions such as
  1315 
  1316   inductive EVEN ODD
  1317     intrs
  1318       null "0 : EVEN"
  1319       oddI "n : EVEN ==> Suc n : ODD"
  1320       evenI "n : ODD ==> Suc n : EVEN"
  1321 
  1322 new theorem list "elims" contains an elimination rule for each of the
  1323 recursive sets; inductive definitions now handle disjunctive premises
  1324 correctly (also ZF);
  1325 
  1326 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1327 "mutual_induct" no longer exists - the induction rule is always
  1328 contained in "induct";
  1329 
  1330 
  1331 * HOL/datatype package re-implemented and greatly improved: now
  1332 supports mutually recursive datatypes such as
  1333 
  1334   datatype
  1335     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1336             | SUM ('a aexp) ('a aexp)
  1337             | DIFF ('a aexp) ('a aexp)
  1338             | NUM 'a
  1339   and
  1340     'a bexp = LESS ('a aexp) ('a aexp)
  1341             | AND ('a bexp) ('a bexp)
  1342             | OR ('a bexp) ('a bexp)
  1343 
  1344 as well as indirectly recursive datatypes such as
  1345 
  1346   datatype
  1347     ('a, 'b) term = Var 'a
  1348                   | App 'b ((('a, 'b) term) list)
  1349 
  1350 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1351 induction on mutually / indirectly recursive datatypes.
  1352 
  1353 Primrec equations are now stored in theory and can be accessed via
  1354 <function_name>.simps.
  1355 
  1356 INCOMPATIBILITIES:
  1357 
  1358   - Theories using datatypes must now have theory Datatype as an
  1359     ancestor.
  1360   - The specific <typename>.induct_tac no longer exists - use the
  1361     generic induct_tac instead.
  1362   - natE has been renamed to nat.exhaust - use exhaust_tac
  1363     instead of res_inst_tac ... natE. Note that the variable
  1364     names in nat.exhaust differ from the names in natE, this
  1365     may cause some "fragile" proofs to fail.
  1366   - The theorems split_<typename>_case and split_<typename>_case_asm
  1367     have been renamed to <typename>.split and <typename>.split_asm.
  1368   - Since default sorts of type variables are now handled correctly,
  1369     some datatype definitions may have to be annotated with explicit
  1370     sort constraints.
  1371   - Primrec definitions no longer require function name and type
  1372     of recursive argument.
  1373 
  1374 Consider using isatool fixdatatype to adapt your theories and proof
  1375 scripts to the new package (backup your sources first!).
  1376 
  1377 
  1378 * HOL/record package: considerably improved implementation; now
  1379 includes concrete syntax for record types, terms, updates; theorems
  1380 for surjective pairing and splitting !!-bound record variables; proof
  1381 support is as follows:
  1382 
  1383   1) standard conversions (selectors or updates applied to record
  1384 constructor terms) are part of the standard simpset;
  1385 
  1386   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1387 made part of standard simpset and claset via addIffs;
  1388 
  1389   3) a tactic for record field splitting (record_split_tac) is part of
  1390 the standard claset (addSWrapper);
  1391 
  1392 To get a better idea about these rules you may retrieve them via
  1393 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1394 the name of your record type.
  1395 
  1396 The split tactic 3) conceptually simplifies by the following rule:
  1397 
  1398   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1399 
  1400 Thus any record variable that is bound by meta-all will automatically
  1401 blow up into some record constructor term, consequently the
  1402 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1403 solve record problems automatically.
  1404 
  1405 
  1406 * reorganized the main HOL image: HOL/Integ and String loaded by
  1407 default; theory Main includes everything;
  1408 
  1409 * automatic simplification of integer sums and comparisons, using cancellation;
  1410 
  1411 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1412 
  1413 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1414 
  1415 * many new identities for unions, intersections, set difference, etc.;
  1416 
  1417 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1418 called split_if, split_split, split_sum_case and split_nat_case (to go
  1419 with add/delsplits);
  1420 
  1421 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1422 (?x::unit) = (); this is made part of the default simpset, which COULD
  1423 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1424 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1425 unit_abs_eta_conv is added in order to counter the effect of
  1426 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1427 %u.f();
  1428 
  1429 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1430 makes more sense);
  1431 
  1432 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1433   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1434   disjointness reasoning but breaking a few old proofs.
  1435 
  1436 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1437 to 'converse' from 'inverse' (for compatibility with ZF and some
  1438 literature);
  1439 
  1440 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1441 the well-founded relation;
  1442 
  1443 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1444     Compl A.  The "Compl" syntax remains available as input syntax for this
  1445     release ONLY.
  1446 
  1447 * HOL/Update: new theory of function updates:
  1448     f(a:=b) == %x. if x=a then b else f x
  1449 may also be iterated as in f(a:=b,c:=d,...);
  1450 
  1451 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1452 
  1453 * HOL/List:
  1454   - new function list_update written xs[i:=v] that updates the i-th
  1455     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1456   - new function `upt' written [i..j(] which generates the list
  1457     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1458     bound write [i..j], which is a shorthand for [i..j+1(].
  1459   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1460 
  1461 * HOL/Arith:
  1462   - removed 'pred' (predecessor) function;
  1463   - generalized some theorems about n-1;
  1464   - many new laws about "div" and "mod";
  1465   - new laws about greatest common divisors (see theory ex/Primes);
  1466 
  1467 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1468 instead of "inverse";
  1469 
  1470 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1471   of the multiset ordering;
  1472 
  1473 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1474   (not included by default);
  1475 
  1476 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1477 
  1478 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1479   programs, i.e. different program variables may have different types.
  1480 
  1481 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1482   [previously, this check worked only if the rewrite rule was unconditional]
  1483   Now rew can involve either definitions or equalities (either == or =).
  1484 
  1485 
  1486 *** ZF ***
  1487 
  1488 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1489   only the theorems proved on ZF.ML;
  1490 
  1491 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1492   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1493   disjointness reasoning but breaking a few old proofs.
  1494 
  1495 * ZF/Update: new theory of function updates
  1496     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1497   may also be iterated as in f(a:=b,c:=d,...);
  1498 
  1499 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1500 
  1501 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1502   [previously, this check worked only if the rewrite rule was unconditional]
  1503   Now rew can involve either definitions or equalities (either == or =).
  1504 
  1505 * case_tac provided for compatibility with HOL
  1506     (like the old excluded_middle_tac, but with subgoals swapped)
  1507 
  1508 
  1509 *** Internal programming interfaces ***
  1510 
  1511 * Pure: several new basic modules made available for general use, see
  1512 also src/Pure/README;
  1513 
  1514 * improved the theory data mechanism to support encapsulation (data
  1515 kind name replaced by private Object.kind, acting as authorization
  1516 key); new type-safe user interface via functor TheoryDataFun; generic
  1517 print_data function becomes basically useless;
  1518 
  1519 * removed global_names compatibility flag -- all theory declarations
  1520 are qualified by default;
  1521 
  1522 * module Pure/Syntax now offers quote / antiquote translation
  1523 functions (useful for Hoare logic etc. with implicit dependencies);
  1524 see HOL/ex/Antiquote for an example use;
  1525 
  1526 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1527 cterm -> thm;
  1528 
  1529 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1530 subgoal;
  1531 
  1532 * Display.print_goals function moved to Locale.print_goals;
  1533 
  1534 * standard print function for goals supports current_goals_markers
  1535 variable for marking begin of proof, end of proof, start of goal; the
  1536 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1537 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1538 for example;
  1539 
  1540 
  1541 
  1542 New in Isabelle98 (January 1998)
  1543 --------------------------------
  1544 
  1545 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1546 
  1547 * changed lexical syntax of terms / types: dots made part of long
  1548 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1549 
  1550 * simpset (and claset) reference variable replaced by functions
  1551 simpset / simpset_ref;
  1552 
  1553 * no longer supports theory aliases (via merge) and non-trivial
  1554 implicit merge of thms' signatures;
  1555 
  1556 * most internal names of constants changed due to qualified names;
  1557 
  1558 * changed Pure/Sequence interface (see Pure/seq.ML);
  1559 
  1560 
  1561 *** General Changes ***
  1562 
  1563 * hierachically structured name spaces (for consts, types, axms, thms
  1564 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1565 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1566 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1567 long_names for fully qualified output names; NOTE: ML programs
  1568 (special tactics, packages etc.) referring to internal names may have
  1569 to be adapted to cope with fully qualified names; in case of severe
  1570 backward campatibility problems try setting 'global_names' at compile
  1571 time to have enrything declared within a flat name space; one may also
  1572 fine tune name declarations in theories via the 'global' and 'local'
  1573 section;
  1574 
  1575 * reimplemented the implicit simpset and claset using the new anytype
  1576 data filed in signatures; references simpset:simpset ref etc. are
  1577 replaced by functions simpset:unit->simpset and
  1578 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1579 to patch your ML files accordingly;
  1580 
  1581 * HTML output now includes theory graph data for display with Java
  1582 applet or isatool browser; data generated automatically via isatool
  1583 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1584 
  1585 * defs may now be conditional; improved rewrite_goals_tac to handle
  1586 conditional equations;
  1587 
  1588 * defs now admits additional type arguments, using TYPE('a) syntax;
  1589 
  1590 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1591 creates a new theory node; implicit merge of thms' signatures is
  1592 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1593 transfer:theory->thm->thm in (rare) cases;
  1594 
  1595 * improved handling of draft signatures / theories; draft thms (and
  1596 ctyps, cterms) are automatically promoted to real ones;
  1597 
  1598 * slightly changed interfaces for oracles: admit many per theory, named
  1599 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1600 
  1601 * print_goals: optional output of const types (set show_consts and
  1602 show_types);
  1603 
  1604 * improved output of warnings (###) and errors (***);
  1605 
  1606 * subgoal_tac displays a warning if the new subgoal has type variables;
  1607 
  1608 * removed old README and Makefiles;
  1609 
  1610 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1611 
  1612 * removed obsolete init_pps and init_database;
  1613 
  1614 * deleted the obsolete tactical STATE, which was declared by
  1615     fun STATE tacfun st = tacfun st st;
  1616 
  1617 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1618 (which abbreviates $HOME);
  1619 
  1620 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1621 use isatool fixseq to adapt your ML programs (this works for fully
  1622 qualified references to the Sequence structure only!);
  1623 
  1624 * use_thy no longer requires writable current directory; it always
  1625 reloads .ML *and* .thy file, if either one is out of date;
  1626 
  1627 
  1628 *** Classical Reasoner ***
  1629 
  1630 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1631 tactics that use classical reasoning to simplify a subgoal without
  1632 splitting it into several subgoals;
  1633 
  1634 * Safe_tac: like safe_tac but uses the default claset;
  1635 
  1636 
  1637 *** Simplifier ***
  1638 
  1639 * added simplification meta rules:
  1640     (asm_)(full_)simplify: simpset -> thm -> thm;
  1641 
  1642 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1643 logics (again);
  1644 
  1645 * added prems argument to simplification procedures;
  1646 
  1647 * HOL, FOL, ZF: added infix function `addsplits':
  1648   instead of `<simpset> setloop (split_tac <thms>)'
  1649   you can simply write `<simpset> addsplits <thms>'
  1650 
  1651 
  1652 *** Syntax ***
  1653 
  1654 * TYPE('a) syntax for type reflection terms;
  1655 
  1656 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1657 
  1658 * pretty printer: changed order of mixfix annotation preference (again!);
  1659 
  1660 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1661 
  1662 
  1663 *** HOL ***
  1664 
  1665 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1666   with `addloop' of the simplifier to faciliate case splitting in premises.
  1667 
  1668 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1669 
  1670 * HOL/Auth: new protocol proofs including some for the Internet
  1671   protocol TLS;
  1672 
  1673 * HOL/Map: new theory of `maps' a la VDM;
  1674 
  1675 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1676 cancelling out common nat summands from =, <, <= (in)equalities, or
  1677 differences; simplification procedures nat_cancel_factor for
  1678 cancelling common factor from =, <, <= (in)equalities over natural
  1679 sums; nat_cancel contains both kinds of procedures, it is installed by
  1680 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1681 
  1682 * HOL/simplifier: terms of the form
  1683   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1684   are rewritten to
  1685   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1686   and those of the form
  1687   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1688   are rewritten to
  1689   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1690 
  1691 * HOL/datatype
  1692   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1693 
  1694   P(t_case f1 ... fn x) =
  1695      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1696         ...
  1697        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1698      )
  1699 
  1700   and a theorem `split_t_case_asm' of the form
  1701 
  1702   P(t_case f1 ... fn x) =
  1703     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1704         ...
  1705        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1706      )
  1707   which can be added to a simpset via `addsplits'. The existing theorems
  1708   expand_list_case and expand_option_case have been renamed to
  1709   split_list_case and split_option_case.
  1710 
  1711 * HOL/Arithmetic:
  1712   - `pred n' is automatically converted to `n-1'.
  1713     Users are strongly encouraged not to use `pred' any longer,
  1714     because it will disappear altogether at some point.
  1715   - Users are strongly encouraged to write "0 < n" rather than
  1716     "n ~= 0". Theorems and proof tools have been modified towards this
  1717     `standard'.
  1718 
  1719 * HOL/Lists:
  1720   the function "set_of_list" has been renamed "set" (and its theorems too);
  1721   the function "nth" now takes its arguments in the reverse order and
  1722   has acquired the infix notation "!" as in "xs!n".
  1723 
  1724 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1725 
  1726 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1727   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1728 
  1729 * HOL/record: extensible records with schematic structural subtyping
  1730 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1731 still lacks various theorems and concrete record syntax;
  1732 
  1733 
  1734 *** HOLCF ***
  1735 
  1736 * removed "axioms" and "generated by" sections;
  1737 
  1738 * replaced "ops" section by extended "consts" section, which is capable of
  1739   handling the continuous function space "->" directly;
  1740 
  1741 * domain package:
  1742   . proves theorems immediately and stores them in the theory,
  1743   . creates hierachical name space,
  1744   . now uses normal mixfix annotations (instead of cinfix...),
  1745   . minor changes to some names and values (for consistency),
  1746   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1747   . separator between mutual domain defs: changed "," to "and",
  1748   . improved handling of sort constraints;  now they have to
  1749     appear on the left-hand side of the equations only;
  1750 
  1751 * fixed LAM <x,y,zs>.b syntax;
  1752 
  1753 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1754 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1755 
  1756 
  1757 *** FOL and ZF ***
  1758 
  1759 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1760   with `addloop' of the simplifier to faciliate case splitting in premises.
  1761 
  1762 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1763 in HOL, they strip ALL and --> from proved theorems;
  1764 
  1765 
  1766 
  1767 New in Isabelle94-8 (May 1997)
  1768 ------------------------------
  1769 
  1770 *** General Changes ***
  1771 
  1772 * new utilities to build / run / maintain Isabelle etc. (in parts
  1773 still somewhat experimental); old Makefiles etc. still functional;
  1774 
  1775 * new 'Isabelle System Manual';
  1776 
  1777 * INSTALL text, together with ./configure and ./build scripts;
  1778 
  1779 * reimplemented type inference for greater efficiency, better error
  1780 messages and clean internal interface;
  1781 
  1782 * prlim command for dealing with lots of subgoals (an easier way of
  1783 setting goals_limit);
  1784 
  1785 
  1786 *** Syntax ***
  1787 
  1788 * supports alternative (named) syntax tables (parser and pretty
  1789 printer); internal interface is provided by add_modesyntax(_i);
  1790 
  1791 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1792 be used in conjunction with the Isabelle symbol font; uses the
  1793 "symbols" syntax table;
  1794 
  1795 * added token_translation interface (may translate name tokens in
  1796 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1797 the current print_mode); IMPORTANT: user print translation functions
  1798 are responsible for marking newly introduced bounds
  1799 (Syntax.mark_boundT);
  1800 
  1801 * token translations for modes "xterm" and "xterm_color" that display
  1802 names in bold, underline etc. or colors (which requires a color
  1803 version of xterm);
  1804 
  1805 * infixes may now be declared with names independent of their syntax;
  1806 
  1807 * added typed_print_translation (like print_translation, but may
  1808 access type of constant);
  1809 
  1810 
  1811 *** Classical Reasoner ***
  1812 
  1813 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1814 some limitations.  Blast_tac...
  1815   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1816   + ignores elimination rules that don't have the correct format
  1817         (the conclusion MUST be a formula variable)
  1818   + ignores types, which can make HOL proofs fail
  1819   + rules must not require higher-order unification, e.g. apply_type in ZF
  1820     [message "Function Var's argument not a bound variable" relates to this]
  1821   + its proof strategy is more general but can actually be slower
  1822 
  1823 * substitution with equality assumptions no longer permutes other
  1824 assumptions;
  1825 
  1826 * minor changes in semantics of addafter (now called addaltern); renamed
  1827 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1828 (and access functions for it);
  1829 
  1830 * improved combination of classical reasoner and simplifier:
  1831   + functions for handling clasimpsets
  1832   + improvement of addss: now the simplifier is called _after_ the
  1833     safe steps.
  1834   + safe variant of addss called addSss: uses safe simplifications
  1835     _during_ the safe steps. It is more complete as it allows multiple
  1836     instantiations of unknowns (e.g. with slow_tac).
  1837 
  1838 *** Simplifier ***
  1839 
  1840 * added interface for simplification procedures (functions that
  1841 produce *proven* rewrite rules on the fly, depending on current
  1842 redex);
  1843 
  1844 * ordering on terms as parameter (used for ordered rewriting);
  1845 
  1846 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1847 
  1848 * the solver is now split into a safe and an unsafe part.
  1849 This should be invisible for the normal user, except that the
  1850 functions setsolver and addsolver have been renamed to setSolver and
  1851 addSolver; added safe_asm_full_simp_tac;
  1852 
  1853 
  1854 *** HOL ***
  1855 
  1856 * a generic induction tactic `induct_tac' which works for all datatypes and
  1857 also for type `nat';
  1858 
  1859 * a generic case distinction tactic `exhaust_tac' which works for all
  1860 datatypes and also for type `nat';
  1861 
  1862 * each datatype comes with a function `size';
  1863 
  1864 * patterns in case expressions allow tuple patterns as arguments to
  1865 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1866 
  1867 * primrec now also works with type nat;
  1868 
  1869 * recdef: a new declaration form, allows general recursive functions to be
  1870 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1871 
  1872 * the constant for negation has been renamed from "not" to "Not" to
  1873 harmonize with FOL, ZF, LK, etc.;
  1874 
  1875 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1876 infinite lists;
  1877 
  1878 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1879 
  1880 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1881 problems in commutative rings, using axiomatic type classes for + and *;
  1882 
  1883 * more examples in HOL/MiniML and HOL/Auth;
  1884 
  1885 * more default rewrite rules for quantifiers, union/intersection;
  1886 
  1887 * a new constant `arbitrary == @x.False';
  1888 
  1889 * HOLCF/IOA replaces old HOL/IOA;
  1890 
  1891 * HOLCF changes: derived all rules and arities
  1892   + axiomatic type classes instead of classes
  1893   + typedef instead of faking type definitions
  1894   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1895   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1896   + eliminated the types void, one, tr
  1897   + use unit lift and bool lift (with translations) instead of one and tr
  1898   + eliminated blift from Lift3.thy (use Def instead of blift)
  1899   all eliminated rules are derived as theorems --> no visible changes ;
  1900 
  1901 
  1902 *** ZF ***
  1903 
  1904 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1905 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1906 as ZF_cs addSIs [equalityI];
  1907 
  1908 
  1909 
  1910 New in Isabelle94-7 (November 96)
  1911 ---------------------------------
  1912 
  1913 * allowing negative levels (as offsets) in prlev and choplev;
  1914 
  1915 * super-linear speedup for large simplifications;
  1916 
  1917 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1918 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1919 FAIL); can suppress it using the command Delsimps (ex_simps @
  1920 all_simps); De Morgan laws are also now included, by default;
  1921 
  1922 * improved printing of ==>  :  ~:
  1923 
  1924 * new object-logic "Sequents" adds linear logic, while replacing LK
  1925 and Modal (thanks to Sara Kalvala);
  1926 
  1927 * HOL/Auth: correctness proofs for authentication protocols;
  1928 
  1929 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1930 examples on HOL/Auth);
  1931 
  1932 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1933 the rewriter and classical reasoner simultaneously;
  1934 
  1935 * function uresult no longer returns theorems in "standard" format;
  1936 regain previous version by: val uresult = standard o uresult;
  1937 
  1938 
  1939 
  1940 New in Isabelle94-6
  1941 -------------------
  1942 
  1943 * oracles -- these establish an interface between Isabelle and trusted
  1944 external reasoners, which may deliver results as theorems;
  1945 
  1946 * proof objects (in particular record all uses of oracles);
  1947 
  1948 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1949 
  1950 * "constdefs" section in theory files;
  1951 
  1952 * "primrec" section (HOL) no longer requires names;
  1953 
  1954 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1955 
  1956 
  1957 
  1958 New in Isabelle94-5
  1959 -------------------
  1960 
  1961 * reduced space requirements;
  1962 
  1963 * automatic HTML generation from theories;
  1964 
  1965 * theory files no longer require "..." (quotes) around most types;
  1966 
  1967 * new examples, including two proofs of the Church-Rosser theorem;
  1968 
  1969 * non-curried (1994) version of HOL is no longer distributed;
  1970 
  1971 
  1972 
  1973 New in Isabelle94-4
  1974 -------------------
  1975 
  1976 * greatly reduced space requirements;
  1977 
  1978 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1979 
  1980 * searchable theorem database (see the section "Retrieving theorems" on
  1981 page 8 of the Reference Manual);
  1982 
  1983 * new examples, including Grabczewski's monumental case study of the
  1984 Axiom of Choice;
  1985 
  1986 * The previous version of HOL renamed to Old_HOL;
  1987 
  1988 * The new version of HOL (previously called CHOL) uses a curried syntax
  1989 for functions.  Application looks like f a b instead of f(a,b);
  1990 
  1991 * Mutually recursive inductive definitions finally work in HOL;
  1992 
  1993 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1994 translates to the operator "split";
  1995 
  1996 
  1997 
  1998 New in Isabelle94-3
  1999 -------------------
  2000 
  2001 * new infix operator, addss, allowing the classical reasoner to
  2002 perform simplification at each step of its search.  Example:
  2003         fast_tac (cs addss ss)
  2004 
  2005 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2006 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2007 look like (a,b) instead of <a,b>;
  2008 
  2009 * PLEASE NOTE: CHOL will eventually replace HOL!
  2010 
  2011 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2012 It translates to the operator "split".  A new theory of integers is available;
  2013 
  2014 * In ZF, integer numerals now denote two's-complement binary integers.
  2015 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2016 
  2017 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2018 of the Axiom of Choice;
  2019 
  2020 
  2021 
  2022 New in Isabelle94-2
  2023 -------------------
  2024 
  2025 * Significantly faster resolution;
  2026 
  2027 * the different sections in a .thy file can now be mixed and repeated
  2028 freely;
  2029 
  2030 * Database of theorems for FOL, HOL and ZF.  New
  2031 commands including qed, qed_goal and bind_thm store theorems in the database.
  2032 
  2033 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2034 a given theory (thms_of), or find out what theory a theorem was proved in
  2035 (theory_of_thm);
  2036 
  2037 * Bugs fixed in the inductive definition and datatype packages;
  2038 
  2039 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2040 and HOL_dup_cs obsolete;
  2041 
  2042 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2043 have been removed;
  2044 
  2045 * Simpler definition of function space in ZF;
  2046 
  2047 * new results about cardinal and ordinal arithmetic in ZF;
  2048 
  2049 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2050 types;
  2051 
  2052 
  2053 $Id$