NEWS
author paulson
Tue Nov 20 10:48:38 2001 +0100 (2001-11-20)
changeset 12245 3dd9aae402bb
parent 12210 2f510d8d8291
child 12253 1886dc96b7e9
permissions -rw-r--r--
Hyperreal
     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 Kammüller, 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 Kammüller;
   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 '(co)inductive', '(co)datatype',
   213 'rep_datatype', 'inductive_cases'; also methods 'ind_cases',
   214 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   215 
   216 * ZF: the integer library now covers quotients and remainders, with
   217 many laws relating division to addition, multiplication, etc.;
   218 
   219 * ZF/Induct: new directory for examples of inductive definitions,
   220 including theory Multiset for multiset orderings;
   221 
   222 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   223 typeless version of the formalism;
   224 
   225 
   226 *** General ***
   227 
   228 * kernel: meta-level proof terms (by Stefan Berghofer), see also ref
   229 manual;
   230 
   231 * Pure/axclass: removed obsolete ML interface goal_subclass/goal_arity;
   232 
   233 * classical: renamed addaltern to addafter, addSaltern to addSafter;
   234 
   235 * clasimp: ``iff'' declarations now handle conditional rules as well;
   236 
   237 * syntax: new token syntax "num" for plain numerals (without "#" of
   238 "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now separate
   239 tokens, so expressions involving minus need to be spaced properly;
   240 
   241 * syntax: support non-oriented infixes;
   242 
   243 * syntax: print modes "type_brackets" and "no_type_brackets" control
   244 output of nested => (types); the default behavior is "type_brackets";
   245 
   246 * syntax: builtin parse translation for "_constify" turns valued
   247 tokens into AST constants;
   248 
   249 * system: refrain from any attempt at filtering input streams; no
   250 longer support ``8bit'' encoding of old isabelle font, instead proper
   251 iso-latin characters may now be used;
   252 
   253 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   254 
   255 * system: Proof General keywords specification is now part of the
   256 Isabelle distribution (see etc/isar-keywords.el);
   257 
   258 * system: smart selection of Isabelle process versus Isabelle
   259 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   260 run both "isabelle" and "Isabelle" even if file names are badly
   261 damaged (executable inspects the case of the first letter of its own
   262 name); added separate "isabelle-process" and "isabelle-interface";
   263 
   264 
   265 
   266 New in Isabelle99-2 (February 2001)
   267 -----------------------------------
   268 
   269 *** Overview of INCOMPATIBILITIES ***
   270 
   271 * HOL: please note that theories in the Library and elsewhere often use the
   272 new-style (Isar) format; to refer to their theorems in an ML script you must
   273 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   274 
   275 * HOL: inductive package no longer splits induction rule aggressively,
   276 but only as far as specified by the introductions given; the old
   277 format may be recovered via ML function complete_split_rule or attribute
   278 'split_rule (complete)';
   279 
   280 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   281 gfp_Tarski to gfp_unfold;
   282 
   283 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   284 
   285 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   286 relation); infix "^^" has been renamed "``"; infix "``" has been
   287 renamed "`"; "univalent" has been renamed "single_valued";
   288 
   289 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   290 operation;
   291 
   292 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   293 
   294 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   295 
   296 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   297 consequence, it is no longer monotonic wrt. the local goal context
   298 (which is now passed through the inductive cases);
   299 
   300 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   301 \<gg> to \<ggreater>;
   302 
   303 
   304 *** Document preparation ***
   305 
   306 * \isabellestyle{NAME} selects version of Isabelle output (currently
   307 available: are "it" for near math-mode best-style output, "sl" for
   308 slanted text style, and "tt" for plain type-writer; if no
   309 \isabellestyle command is given, output is according to slanted
   310 type-writer);
   311 
   312 * support sub/super scripts (for single symbols only), input syntax is
   313 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   314 
   315 * some more standard symbols; see Appendix A of the system manual for
   316 the complete list of symbols defined in isabellesym.sty;
   317 
   318 * improved isabelle style files; more abstract symbol implementation
   319 (should now use \isamath{...} and \isatext{...} in custom symbol
   320 definitions);
   321 
   322 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   323 state; Note that presentation of goal states does not conform to
   324 actual human-readable proof documents.  Please do not include goal
   325 states into document output unless you really know what you are doing!
   326 
   327 * proper indentation of antiquoted output with proportional LaTeX
   328 fonts;
   329 
   330 * no_document ML operator temporarily disables LaTeX document
   331 generation;
   332 
   333 * isatool unsymbolize tunes sources for plain ASCII communication;
   334 
   335 
   336 *** Isar ***
   337 
   338 * Pure: Isar now suffers initial goal statements to contain unbound
   339 schematic variables (this does not conform to actual readable proof
   340 documents, due to unpredictable outcome and non-compositional proof
   341 checking); users who know what they are doing may use schematic goals
   342 for Prolog-style synthesis of proven results;
   343 
   344 * Pure: assumption method (an implicit finishing) now handles actual
   345 rules as well;
   346 
   347 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   348 initial goal, declare "that" only as Pure intro (only for single
   349 steps); the "that" rule assumption may now be involved in implicit
   350 finishing, thus ".." becomes a feasible for trivial obtains;
   351 
   352 * Pure: default proof step now includes 'intro_classes'; thus trivial
   353 instance proofs may be performed by "..";
   354 
   355 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   356 statements as well;
   357 
   358 * Pure: more robust selection of calculational rules;
   359 
   360 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   361 rule (as well as the assumption rule);
   362 
   363 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   364 lemmas, using the graph browser tool;
   365 
   366 * Pure: predict failure of "show" in interactive mode;
   367 
   368 * Pure: 'thms_containing' now takes actual terms as arguments;
   369 
   370 * HOL: improved method 'induct' --- now handles non-atomic goals
   371 (potential INCOMPATIBILITY); tuned error handling;
   372 
   373 * HOL: cases and induct rules now provide explicit hints about the
   374 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   375 any remaining facts are inserted into the goal verbatim;
   376 
   377 * HOL: local contexts (aka cases) may now contain term bindings as
   378 well; the 'cases' and 'induct' methods new provide a ?case binding for
   379 the result to be shown in each case;
   380 
   381 * HOL: added 'recdef_tc' command;
   382 
   383 * isatool convert assists in eliminating legacy ML scripts;
   384 
   385 
   386 *** HOL ***
   387 
   388 * HOL/Library: a collection of generic theories to be used together
   389 with main HOL; the theory loader path already includes this directory
   390 by default; the following existing theories have been moved here:
   391 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   392 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   393 
   394 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   395 modelling and verification task performed in Isabelle/HOL +
   396 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   397 
   398 * HOL/Algebra: special summation operator SUM no longer exists, it has
   399 been replaced by setsum; infix 'assoc' now has priority 50 (like
   400 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   401 'domain', this makes the theory consistent with mathematical
   402 literature;
   403 
   404 * HOL basics: added overloaded operations "inverse" and "divide"
   405 (infix "/"), syntax for generic "abs" operation, generic summation
   406 operator \<Sum>;
   407 
   408 * HOL/typedef: simplified package, provide more useful rules (see also
   409 HOL/subset.thy);
   410 
   411 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   412 now expressed as a proper nested rule (old-style tactic scripts may
   413 require atomize_strip_tac to cope with non-atomic premises);
   414 
   415 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   416 to "split_conv" (old name still available for compatibility);
   417 
   418 * HOL: improved concrete syntax for strings (e.g. allows translation
   419 rules with string literals);
   420 
   421 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   422  and Fleuriot's mechanization of analysis, including the transcendental
   423  functions for the reals;
   424 
   425 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   426 
   427 
   428 *** CTT ***
   429 
   430 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   431 "lam" is displayed as TWO lambda-symbols
   432 
   433 * CTT: theory Main now available, containing everything (that is, Bool
   434 and Arith);
   435 
   436 
   437 *** General ***
   438 
   439 * Pure: the Simplifier has been implemented properly as a derived rule
   440 outside of the actual kernel (at last!); the overall performance
   441 penalty in practical applications is about 50%, while reliability of
   442 the Isabelle inference kernel has been greatly improved;
   443 
   444 * print modes "brackets" and "no_brackets" control output of nested =>
   445 (types) and ==> (props); the default behaviour is "brackets";
   446 
   447 * Provers: fast_tac (and friends) now handle actual object-logic rules
   448 as assumptions as well;
   449 
   450 * system: support Poly/ML 4.0;
   451 
   452 * system: isatool install handles KDE version 1 or 2;
   453 
   454 
   455 
   456 New in Isabelle99-1 (October 2000)
   457 ----------------------------------
   458 
   459 *** Overview of INCOMPATIBILITIES ***
   460 
   461 * HOL: simplification of natural numbers is much changed; to partly
   462 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   463 issue the following ML commands:
   464 
   465   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   466   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   467 
   468 * HOL: simplification no longer dives into case-expressions; this is
   469 controlled by "t.weak_case_cong" for each datatype t;
   470 
   471 * HOL: nat_less_induct renamed to less_induct;
   472 
   473 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   474 fixsome to patch .thy and .ML sources automatically;
   475 
   476   select_equality  -> some_equality
   477   select_eq_Ex     -> some_eq_ex
   478   selectI2EX       -> someI2_ex
   479   selectI2         -> someI2
   480   selectI          -> someI
   481   select1_equality -> some1_equality
   482   Eps_sym_eq       -> some_sym_eq_trivial
   483   Eps_eq           -> some_eq_trivial
   484 
   485 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   486 
   487 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   488 instead);
   489 
   490 * HOL: the recursion equations generated by 'recdef' are now called
   491 f.simps instead of f.rules;
   492 
   493 * HOL: qed_spec_mp now also handles bounded ALL as well;
   494 
   495 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   496 sometimes be needed;
   497 
   498 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   499 
   500 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   501 
   502 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   503 product is now "<*>" instead of "Times"; the lexicographic product is
   504 now "<*lex*>" instead of "**";
   505 
   506 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   507 of main HOL, but was unused); better use HOL's datatype package;
   508 
   509 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   510 the old syntax may be recovered as follows:
   511 
   512   syntax (symbols)
   513     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   514       (infixl "\\<oplus>" 100)
   515 
   516 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   517 
   518 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   519 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   520 internally;
   521 
   522 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   523 changed from A/r to A//r;
   524 
   525 * ZF: new treatment of arithmetic (nat & int) may break some old
   526 proofs;
   527 
   528 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   529 rulify -> rule_format, elimify -> elim_format, ...);
   530 
   531 * Isar/Provers: intro/elim/dest attributes changed; renamed
   532 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   533 should have to change intro!! to intro? only); replaced "delrule" by
   534 "rule del";
   535 
   536 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   537 
   538 * Provers: strengthened force_tac by using new first_best_tac;
   539 
   540 * LaTeX document preparation: several changes of isabelle.sty (see
   541 lib/texinputs);
   542 
   543 
   544 *** Document preparation ***
   545 
   546 * formal comments (text blocks etc.) in new-style theories may now
   547 contain antiquotations of thm/prop/term/typ/text to be presented
   548 according to latex print mode; concrete syntax is like this:
   549 @{term[show_types] "f(x) = a + x"};
   550 
   551 * isatool mkdir provides easy setup of Isabelle session directories,
   552 including proper document sources;
   553 
   554 * generated LaTeX sources are now deleted after successful run
   555 (isatool document -c); may retain a copy somewhere else via -D option
   556 of isatool usedir;
   557 
   558 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   559 style files, achieving self-contained LaTeX sources and simplifying
   560 LaTeX debugging;
   561 
   562 * old-style theories now produce (crude) LaTeX output as well;
   563 
   564 * browser info session directories are now self-contained (may be put
   565 on WWW server seperately); improved graphs of nested sessions; removed
   566 graph for 'all sessions';
   567 
   568 * several improvements in isabelle style files; \isabellestyle{it}
   569 produces fake math mode output; \isamarkupheader is now \section by
   570 default; see lib/texinputs/isabelle.sty etc.;
   571 
   572 
   573 *** Isar ***
   574 
   575 * Isar/Pure: local results and corresponding term bindings are now
   576 subject to Hindley-Milner polymorphism (similar to ML); this
   577 accommodates incremental type-inference very nicely;
   578 
   579 * Isar/Pure: new derived language element 'obtain' supports
   580 generalized existence reasoning;
   581 
   582 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   583 support accumulation of results, without applying any rules yet;
   584 useful to collect intermediate results without explicit name
   585 references, and for use with transitivity rules with more than 2
   586 premises;
   587 
   588 * Isar/Pure: scalable support for case-analysis type proofs: new
   589 'case' language element refers to local contexts symbolically, as
   590 produced by certain proof methods; internally, case names are attached
   591 to theorems as "tags";
   592 
   593 * Isar/Pure: theory command 'hide' removes declarations from
   594 class/type/const name spaces;
   595 
   596 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   597 indicate potential overloading;
   598 
   599 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   600 
   601 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   602 "{a,b,c}" instead of {a,b,c};
   603 
   604 * Isar/Pure now provides its own version of intro/elim/dest
   605 attributes; useful for building new logics, but beware of confusion
   606 with the version in Provers/classical;
   607 
   608 * Isar/Pure: the local context of (non-atomic) goals is provided via
   609 case name 'antecedent';
   610 
   611 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   612 to the current context is now done automatically);
   613 
   614 * Isar/Pure: theory command 'method_setup' provides a simple interface
   615 for definining proof methods in ML;
   616 
   617 * Isar/Provers: intro/elim/dest attributes changed; renamed
   618 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   619 most cases, one should have to change intro!! to intro? only);
   620 replaced "delrule" by "rule del";
   621 
   622 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   623 'symmetric' attribute (the latter supercedes [RS sym]);
   624 
   625 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   626 method modifier); 'simp' method: 'only:' modifier removes loopers as
   627 well (including splits);
   628 
   629 * Isar/Provers: Simplifier and Classical methods now support all kind
   630 of modifiers used in the past, including 'cong', 'iff', etc.
   631 
   632 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   633 of Simplifier and Classical reasoner);
   634 
   635 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   636 now support named cases; major packages (inductive, datatype, primrec,
   637 recdef) support case names and properly name parameters;
   638 
   639 * Isar/HOL: new transitivity rules for substitution in inequalities --
   640 monotonicity conditions are extracted to be proven at end of
   641 calculations;
   642 
   643 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   644 method anyway;
   645 
   646 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   647 split_if split_if_asm; datatype package provides theorems foo.splits =
   648 foo.split foo.split_asm for each datatype;
   649 
   650 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   651 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   652 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   653 use "(cases (simplified))" method in proper proof texts);
   654 
   655 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   656 
   657 * Isar: names of theorems etc. may be natural numbers as well;
   658 
   659 * Isar: 'pr' command: optional arguments for goals_limit and
   660 ProofContext.prems_limit; no longer prints theory contexts, but only
   661 proof states;
   662 
   663 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   664 additional print modes to be specified; e.g. "pr(latex)" will print
   665 proof state according to the Isabelle LaTeX style;
   666 
   667 * Isar: improved support for emulating tactic scripts, including proof
   668 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   669 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   670 (for HOL datatypes);
   671 
   672 * Isar: simplified (more robust) goal selection of proof methods: 1st
   673 goal, all goals, or explicit goal specifier (tactic emulation); thus
   674 'proof method scripts' have to be in depth-first order;
   675 
   676 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   677 
   678 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   679 should instead use individual commands for printing items
   680 (print_commands, print_methods etc.);
   681 
   682 * Isar: added 'nothing' --- the empty list of theorems;
   683 
   684 
   685 *** HOL ***
   686 
   687 * HOL/MicroJava: formalization of a fragment of Java, together with a
   688 corresponding virtual machine and a specification of its bytecode
   689 verifier and a lightweight bytecode verifier, including proofs of
   690 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   691 Cornelia Pusch (see also the homepage of project Bali at
   692 http://isabelle.in.tum.de/Bali/);
   693 
   694 * HOL/Algebra: new theory of rings and univariate polynomials, by
   695 Clemens Ballarin;
   696 
   697 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   698 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   699 Rasmussen;
   700 
   701 * HOL/Lattice: fundamental concepts of lattice theory and order
   702 structures, including duals, properties of bounds versus algebraic
   703 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   704 Theorem for complete lattices etc.; may also serve as a demonstration
   705 for abstract algebraic reasoning using axiomatic type classes, and
   706 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   707 
   708 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   709 von Oheimb;
   710 
   711 * HOL/IMPP: extension of IMP with local variables and mutually
   712 recursive procedures, by David von Oheimb;
   713 
   714 * HOL/Lambda: converted into new-style theory and document;
   715 
   716 * HOL/ex/Multiquote: example of multiple nested quotations and
   717 anti-quotations -- basically a generalized version of de-Bruijn
   718 representation; very useful in avoiding lifting of operations;
   719 
   720 * HOL/record: added general record equality rule to simpset; fixed
   721 select-update simplification procedure to handle extended records as
   722 well; admit "r" as field name;
   723 
   724 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   725 other numeric types and also as the identity of groups, rings, etc.;
   726 
   727 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   728 Types nat and int belong to this axclass;
   729 
   730 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   731    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   732    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   733   two terms #m*u and #n*u are replaced by #(m+n)*u
   734     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   735   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   736     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   737 
   738 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   739 powerful prover for predicate logic but knows nothing of clasets; see
   740 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   741 
   742 * HOL: new version of "case_tac" subsumes both boolean case split and
   743 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   744 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   745 
   746 * HOL: simplification no longer dives into case-expressions: only the
   747 selector expression is simplified, but not the remaining arms; to
   748 enable full simplification of case-expressions for datatype t, you may
   749 remove t.weak_case_cong from the simpset, either globally (Delcongs
   750 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   751 
   752 * HOL/recdef: the recursion equations generated by 'recdef' for
   753 function 'f' are now called f.simps instead of f.rules; if all
   754 termination conditions are proved automatically, these simplification
   755 rules are added to the simpset, as in primrec; rules may be named
   756 individually as well, resulting in a separate list of theorems for
   757 each equation;
   758 
   759 * HOL/While is a new theory that provides a while-combinator. It
   760 permits the definition of tail-recursive functions without the
   761 provision of a termination measure. The latter is necessary once the
   762 invariant proof rule for while is applied.
   763 
   764 * HOL: new (overloaded) notation for the set of elements below/above
   765 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   766 
   767 * HOL: theorems impI, allI, ballI bound as "strip";
   768 
   769 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   770 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   771 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   772 
   773 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   774 
   775 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   776 main HOL, but was unused);
   777 
   778 * HOL: fewer consts declared as global (e.g. have to refer to
   779 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   780 
   781 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   782 in case of overlap with user translations (e.g. judgements over
   783 tuples); (note that the underlying logical represenation is still
   784 bogus);
   785 
   786 
   787 *** ZF ***
   788 
   789 * ZF: simplification automatically cancels common terms in arithmetic
   790 expressions over nat and int;
   791 
   792 * ZF: new treatment of nat to minimize type-checking: all operators
   793 coerce their operands to a natural number using the function natify,
   794 making the algebraic laws unconditional;
   795 
   796 * ZF: as above, for int: operators coerce their operands to an integer
   797 using the function intify;
   798 
   799 * ZF: the integer library now contains many of the usual laws for the
   800 orderings, including $<=, and monotonicity laws for $+ and $*;
   801 
   802 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   803 simplification;
   804 
   805 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   806 to the simplifier and classical reasoner simultaneously;
   807 
   808 
   809 *** General ***
   810 
   811 * Provers: blast_tac now handles actual object-logic rules as
   812 assumptions; note that auto_tac uses blast_tac internally as well;
   813 
   814 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   815 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   816 
   817 * Provers: delrules now handles destruct rules as well (no longer need
   818 explicit make_elim);
   819 
   820 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   821   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   822 use instead the strong form,
   823   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   824 in HOL, FOL and ZF the function cla_make_elim will create such rules
   825 from destruct-rules;
   826 
   827 * Provers: Simplifier.easy_setup provides a fast path to basic
   828 Simplifier setup for new object-logics;
   829 
   830 * Pure: AST translation rules no longer require constant head on LHS;
   831 
   832 * Pure: improved name spaces: ambiguous output is qualified; support
   833 for hiding of names;
   834 
   835 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   836 XSYMBOL_HOME; no longer need to do manual configuration in most
   837 situations;
   838 
   839 * system: compression of ML heaps images may now be controlled via -c
   840 option of isabelle and isatool usedir (currently only observed by
   841 Poly/ML);
   842 
   843 * system: isatool installfonts may handle X-Symbol fonts as well (very
   844 useful for remote X11);
   845 
   846 * system: provide TAGS file for Isabelle sources;
   847 
   848 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   849 order;
   850 
   851 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   852 timing flag supersedes proof_timing and Toplevel.trace;
   853 
   854 * ML: new combinators |>> and |>>> for incremental transformations
   855 with secondary results (e.g. certain theory extensions):
   856 
   857 * ML: PureThy.add_defs gets additional argument to indicate potential
   858 overloading (usually false);
   859 
   860 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   861 results;
   862 
   863 
   864 
   865 New in Isabelle99 (October 1999)
   866 --------------------------------
   867 
   868 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   869 
   870 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   871 are no longer simplified.  (This allows the simplifier to unfold recursive
   872 functional programs.)  To restore the old behaviour, declare
   873 
   874     Delcongs [if_weak_cong];
   875 
   876 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   877 complement;
   878 
   879 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   880 
   881 * HOL/datatype: mutual_induct_tac no longer exists --
   882   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   883 
   884 * HOL/typedef: fixed type inference for representing set; type
   885 arguments now have to occur explicitly on the rhs as type constraints;
   886 
   887 * ZF: The con_defs part of an inductive definition may no longer refer
   888 to constants declared in the same theory;
   889 
   890 * HOL, ZF: the function mk_cases, generated by the inductive
   891 definition package, has lost an argument.  To simplify its result, it
   892 uses the default simpset instead of a supplied list of theorems.
   893 
   894 * HOL/List: the constructors of type list are now Nil and Cons;
   895 
   896 * Simplifier: the type of the infix ML functions
   897         setSSolver addSSolver setSolver addSolver
   898 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   899 for packaging solvers. A solver is created via
   900         mk_solver: string -> (thm list -> int -> tactic) -> solver
   901 where the string argument is only a comment.
   902 
   903 
   904 *** Proof tools ***
   905 
   906 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   907 decision procedure for linear arithmetic. Currently it is used for
   908 types `nat', `int', and `real' in HOL (see below); it can, should and
   909 will be instantiated for other types and logics as well.
   910 
   911 * The simplifier now accepts rewrite rules with flexible heads, eg
   912      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   913   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   914   matching.
   915 
   916 
   917 *** General ***
   918 
   919 * New Isabelle/Isar subsystem provides an alternative to traditional
   920 tactical theorem proving; together with the ProofGeneral/isar user
   921 interface it offers an interactive environment for developing human
   922 readable proof documents (Isar == Intelligible semi-automated
   923 reasoning); for further information see isatool doc isar-ref,
   924 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   925 
   926 * improved and simplified presentation of theories: better HTML markup
   927 (including colors), graph views in several sizes; isatool usedir now
   928 provides a proper interface for user theories (via -P option); actual
   929 document preparation based on (PDF)LaTeX is available as well (for
   930 new-style theories only); see isatool doc system for more information;
   931 
   932 * native support for Proof General, both for classic Isabelle and
   933 Isabelle/Isar;
   934 
   935 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   936 using the graph browser tool;
   937 
   938 * Isabelle manuals now also available as PDF;
   939 
   940 * theory loader rewritten from scratch (may not be fully
   941 bug-compatible); old loadpath variable has been replaced by show_path,
   942 add_path, del_path, reset_path functions; new operations such as
   943 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   944 isatool doc ref);
   945 
   946 * improved isatool install: option -k creates KDE application icon,
   947 option -p DIR installs standalone binaries;
   948 
   949 * added ML_PLATFORM setting (useful for cross-platform installations);
   950 more robust handling of platform specific ML images for SML/NJ;
   951 
   952 * the settings environment is now statically scoped, i.e. it is never
   953 created again in sub-processes invoked from isabelle, isatool, or
   954 Isabelle;
   955 
   956 * path element specification '~~' refers to '$ISABELLE_HOME';
   957 
   958 * in locales, the "assumes" and "defines" parts may be omitted if
   959 empty;
   960 
   961 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   962 long arrows);
   963 
   964 * new print_mode "HTML";
   965 
   966 * new flag show_tags controls display of tags of theorems (which are
   967 basically just comments that may be attached by some tools);
   968 
   969 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   970 mode and goal output format:
   971 
   972 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   973 244c244
   974 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   975 ---
   976 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   977 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   978 181c181
   979 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   980 ---
   981 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   982 
   983 * function bind_thms stores lists of theorems (cf. bind_thm);
   984 
   985 * new shorthand tactics ftac, eatac, datac, fatac;
   986 
   987 * qed (and friends) now accept "" as result name; in that case the
   988 theorem is not stored, but proper checks and presentation of the
   989 result still apply;
   990 
   991 * theorem database now also indexes constants "Trueprop", "all",
   992 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   993 
   994 
   995 *** HOL ***
   996 
   997 ** HOL arithmetic **
   998 
   999 * There are now decision procedures for linear arithmetic over nat and
  1000 int:
  1001 
  1002 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1003 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1004 are treated as atomic; subformulae not involving type `nat' or `int'
  1005 are ignored; quantified subformulae are ignored unless they are
  1006 positive universal or negative existential. The tactic has to be
  1007 invoked by hand and can be a little bit slow. In particular, the
  1008 running time is exponential in the number of occurrences of `min' and
  1009 `max', and `-' on `nat'.
  1010 
  1011 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1012 (negated) (in)equalities among the premises and the conclusion into
  1013 account (i.e. no compound formulae) and does not know about `min' and
  1014 `max', and `-' on `nat'. It is fast and is used automatically by the
  1015 simplifier.
  1016 
  1017 NB: At the moment, these decision procedures do not cope with mixed
  1018 nat/int formulae where the two parts interact, such as `m < n ==>
  1019 int(m) < int(n)'.
  1020 
  1021 * HOL/Numeral provides a generic theory of numerals (encoded
  1022 efficiently as bit strings); setup for types nat/int/real is in place;
  1023 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1024 int, existing theories and proof scripts may require a few additional
  1025 type constraints;
  1026 
  1027 * integer division and remainder can now be performed on constant
  1028 arguments;
  1029 
  1030 * many properties of integer multiplication, division and remainder
  1031 are now available;
  1032 
  1033 * An interface to the Stanford Validity Checker (SVC) is available through the
  1034 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1035 are proved automatically.  SVC must be installed separately, and its results
  1036 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1037 invocation of the underlying oracle).  For SVC see
  1038   http://verify.stanford.edu/SVC
  1039 
  1040 * IsaMakefile: the HOL-Real target now builds an actual image;
  1041 
  1042 
  1043 ** HOL misc **
  1044 
  1045 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1046 (in Isabelle/Isar) -- by Gertrud Bauer;
  1047 
  1048 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1049 analysis for assembly languages with subtypes;
  1050 
  1051 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1052 -- avoids syntactic ambiguities and treats state, transition, and
  1053 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1054 changed syntax and (many) tactics;
  1055 
  1056 * HOL/inductive: Now also handles more general introduction rules such
  1057   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1058   theorems are now maintained within the theory (maintained via the
  1059   "mono" attribute);
  1060 
  1061 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1062   (using function types) such as
  1063 
  1064   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1065 
  1066 * HOL/record: record_simproc (part of the default simpset) takes care
  1067 of selectors applied to updated records; record_split_tac is no longer
  1068 part of the default claset; update_defs may now be removed from the
  1069 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1070 
  1071   claset_ref () := claset() addSWrapper record_split_wrapper;
  1072   Delsimprocs [record_simproc]
  1073 
  1074 * HOL/typedef: fixed type inference for representing set; type
  1075 arguments now have to occur explicitly on the rhs as type constraints;
  1076 
  1077 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1078 names rather than an ML expression;
  1079 
  1080 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1081 supplied later.  Program schemes can be defined, such as
  1082     "While B C s = (if B s then While B C (C s) else s)"
  1083 where the well-founded relation can be chosen after B and C have been given.
  1084 
  1085 * HOL/List: the constructors of type list are now Nil and Cons;
  1086 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1087 course, ML tools referring to List.list.op # etc. have to be adapted;
  1088 
  1089 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1090 disabled by default; run isabelle with option -m HOL to get back to
  1091 the original Gordon/HOL-style output;
  1092 
  1093 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1094 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1095 
  1096 * HOL basic syntax simplified (more orthogonal): all variants of
  1097 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1098 Eps operator is provided as well: "SOME x. P[x]";
  1099 
  1100 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1101 
  1102 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1103 thus available for user theories;
  1104 
  1105 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1106 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1107 time;
  1108 
  1109 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1110 several times and then mp;
  1111 
  1112 
  1113 *** LK ***
  1114 
  1115 * the notation <<...>> is now available as a notation for sequences of
  1116 formulas;
  1117 
  1118 * the simplifier is now installed
  1119 
  1120 * the axiom system has been generalized (thanks to Soren Heilmann)
  1121 
  1122 * the classical reasoner now has a default rule database
  1123 
  1124 
  1125 *** ZF ***
  1126 
  1127 * new primrec section allows primitive recursive functions to be given
  1128 directly (as in HOL) over datatypes and the natural numbers;
  1129 
  1130 * new tactics induct_tac and exhaust_tac for induction (or case
  1131 analysis) over datatypes and the natural numbers;
  1132 
  1133 * the datatype declaration of type T now defines the recursor T_rec;
  1134 
  1135 * simplification automatically does freeness reasoning for datatype
  1136 constructors;
  1137 
  1138 * automatic type-inference, with AddTCs command to insert new
  1139 type-checking rules;
  1140 
  1141 * datatype introduction rules are now added as Safe Introduction rules
  1142 to the claset;
  1143 
  1144 * the syntax "if P then x else y" is now available in addition to
  1145 if(P,x,y);
  1146 
  1147 
  1148 *** Internal programming interfaces ***
  1149 
  1150 * tuned simplifier trace output; new flag debug_simp;
  1151 
  1152 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1153 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1154 
  1155 * AxClass.axclass_tac lost the theory argument;
  1156 
  1157 * tuned current_goals_markers semantics: begin / end goal avoids
  1158 printing empty lines;
  1159 
  1160 * removed prs and prs_fn hook, which was broken because it did not
  1161 include \n in its semantics, forcing writeln to add one
  1162 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1163 string -> unit if you really want to output text without newline;
  1164 
  1165 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1166 plain output, interface builders may have to enable 'isabelle_font'
  1167 mode to get Isabelle font glyphs as before;
  1168 
  1169 * refined token_translation interface; INCOMPATIBILITY: output length
  1170 now of type real instead of int;
  1171 
  1172 * theory loader actions may be traced via new ThyInfo.add_hook
  1173 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1174 your own database of information attached to *whole* theories -- as
  1175 opposed to intra-theory data slots offered via TheoryDataFun;
  1176 
  1177 * proper handling of dangling sort hypotheses (at last!);
  1178 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1179 extra sort hypotheses that can be witnessed from the type signature;
  1180 the force_strip_shyps flag is gone, any remaining shyps are simply
  1181 left in the theorem (with a warning issued by strip_shyps_warning);
  1182 
  1183 
  1184 
  1185 New in Isabelle98-1 (October 1998)
  1186 ----------------------------------
  1187 
  1188 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1189 
  1190 * several changes of automated proof tools;
  1191 
  1192 * HOL: major changes to the inductive and datatype packages, including
  1193 some minor incompatibilities of theory syntax;
  1194 
  1195 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1196 called `inj_on';
  1197 
  1198 * HOL: removed duplicate thms in Arith:
  1199   less_imp_add_less  should be replaced by  trans_less_add1
  1200   le_imp_add_le      should be replaced by  trans_le_add1
  1201 
  1202 * HOL: unary minus is now overloaded (new type constraints may be
  1203 required);
  1204 
  1205 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1206 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1207 now taken as an integer constant.
  1208 
  1209 * Pure: ML function 'theory_of' renamed to 'theory';
  1210 
  1211 
  1212 *** Proof tools ***
  1213 
  1214 * Simplifier:
  1215   1. Asm_full_simp_tac is now more aggressive.
  1216      1. It will sometimes reorient premises if that increases their power to
  1217         simplify.
  1218      2. It does no longer proceed strictly from left to right but may also
  1219         rotate premises to achieve further simplification.
  1220      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1221      old Asm_full_simp_tac in that it does not rotate premises.
  1222   2. The simplifier now knows a little bit about nat-arithmetic.
  1223 
  1224 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1225 allows for selected deletion of wrappers, by introduction of names for
  1226 wrapper functionals.  This implies that addbefore, addSbefore,
  1227 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1228 and that adding two tactics with the same name overwrites the first
  1229 one (emitting a warning).
  1230   type wrapper = (int -> tactic) -> (int -> tactic)
  1231   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1232   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1233   delWrapper, delSWrapper: claset *  string            -> claset
  1234   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1235 
  1236 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1237 semantics; addbefore now affects only the unsafe part of step_tac
  1238 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1239 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1240 by Force_tac;
  1241 
  1242 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1243 compWrapper; added safe wrapper (and access functions for it);
  1244 
  1245 * HOL/split_all_tac is now much faster and fails if there is nothing
  1246 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1247 and the names of the automatically generated variables have changed.
  1248 split_all_tac has moved within claset() from unsafe wrappers to safe
  1249 wrappers, which means that !!-bound variables are split much more
  1250 aggressively, and safe_tac and clarify_tac now split such variables.
  1251 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1252 Note: the same holds for record_split_tac, which does the job of
  1253 split_all_tac for record fields.
  1254 
  1255 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1256 permanently to the default simpset using Addsplits just like
  1257 Addsimps. They can be removed via Delsplits just like
  1258 Delsimps. Lower-case versions are also available.
  1259 
  1260 * HOL/Simplifier: The rule split_if is now part of the default
  1261 simpset. This means that the simplifier will eliminate all occurrences
  1262 of if-then-else in the conclusion of a goal. To prevent this, you can
  1263 either remove split_if completely from the default simpset by
  1264 `Delsplits [split_if]' or remove it in a specific call of the
  1265 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1266 other case splitting rules to/from the default simpset: every datatype
  1267 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1268 t is the name of the datatype).
  1269 
  1270 * Classical reasoner / Simplifier combination: new force_tac (and
  1271 derivatives Force_tac, force) combines rewriting and classical
  1272 reasoning (and whatever other tools) similarly to auto_tac, but is
  1273 aimed to solve the given subgoal completely.
  1274 
  1275 
  1276 *** General ***
  1277 
  1278 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1279 and `goalw': the theory is no longer needed as an explicit argument -
  1280 the current theory context is used; assumptions are no longer returned
  1281 at the ML-level unless one of them starts with ==> or !!; it is
  1282 recommended to convert to these new commands using isatool fixgoal
  1283 (backup your sources first!);
  1284 
  1285 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1286 the current theory context, and 'theory' to lookup stored theories;
  1287 
  1288 * new theory section 'locale' for declaring constants, assumptions and
  1289 definitions that have local scope;
  1290 
  1291 * new theory section 'nonterminals' for purely syntactic types;
  1292 
  1293 * new theory section 'setup' for generic ML setup functions
  1294 (e.g. package initialization);
  1295 
  1296 * the distribution now includes Isabelle icons: see
  1297 lib/logo/isabelle-{small,tiny}.xpm;
  1298 
  1299 * isatool install - install binaries with absolute references to
  1300 ISABELLE_HOME/bin;
  1301 
  1302 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1303 
  1304 * print mode 'emacs' reserved for Isamode;
  1305 
  1306 * support multiple print (ast) translations per constant name;
  1307 
  1308 * theorems involving oracles are now printed with a suffixed [!];
  1309 
  1310 
  1311 *** HOL ***
  1312 
  1313 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1314 
  1315 * HOL/inductive package reorganized and improved: now supports mutual
  1316 definitions such as
  1317 
  1318   inductive EVEN ODD
  1319     intrs
  1320       null "0 : EVEN"
  1321       oddI "n : EVEN ==> Suc n : ODD"
  1322       evenI "n : ODD ==> Suc n : EVEN"
  1323 
  1324 new theorem list "elims" contains an elimination rule for each of the
  1325 recursive sets; inductive definitions now handle disjunctive premises
  1326 correctly (also ZF);
  1327 
  1328 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1329 "mutual_induct" no longer exists - the induction rule is always
  1330 contained in "induct";
  1331 
  1332 
  1333 * HOL/datatype package re-implemented and greatly improved: now
  1334 supports mutually recursive datatypes such as
  1335 
  1336   datatype
  1337     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1338             | SUM ('a aexp) ('a aexp)
  1339             | DIFF ('a aexp) ('a aexp)
  1340             | NUM 'a
  1341   and
  1342     'a bexp = LESS ('a aexp) ('a aexp)
  1343             | AND ('a bexp) ('a bexp)
  1344             | OR ('a bexp) ('a bexp)
  1345 
  1346 as well as indirectly recursive datatypes such as
  1347 
  1348   datatype
  1349     ('a, 'b) term = Var 'a
  1350                   | App 'b ((('a, 'b) term) list)
  1351 
  1352 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1353 induction on mutually / indirectly recursive datatypes.
  1354 
  1355 Primrec equations are now stored in theory and can be accessed via
  1356 <function_name>.simps.
  1357 
  1358 INCOMPATIBILITIES:
  1359 
  1360   - Theories using datatypes must now have theory Datatype as an
  1361     ancestor.
  1362   - The specific <typename>.induct_tac no longer exists - use the
  1363     generic induct_tac instead.
  1364   - natE has been renamed to nat.exhaust - use exhaust_tac
  1365     instead of res_inst_tac ... natE. Note that the variable
  1366     names in nat.exhaust differ from the names in natE, this
  1367     may cause some "fragile" proofs to fail.
  1368   - The theorems split_<typename>_case and split_<typename>_case_asm
  1369     have been renamed to <typename>.split and <typename>.split_asm.
  1370   - Since default sorts of type variables are now handled correctly,
  1371     some datatype definitions may have to be annotated with explicit
  1372     sort constraints.
  1373   - Primrec definitions no longer require function name and type
  1374     of recursive argument.
  1375 
  1376 Consider using isatool fixdatatype to adapt your theories and proof
  1377 scripts to the new package (backup your sources first!).
  1378 
  1379 
  1380 * HOL/record package: considerably improved implementation; now
  1381 includes concrete syntax for record types, terms, updates; theorems
  1382 for surjective pairing and splitting !!-bound record variables; proof
  1383 support is as follows:
  1384 
  1385   1) standard conversions (selectors or updates applied to record
  1386 constructor terms) are part of the standard simpset;
  1387 
  1388   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1389 made part of standard simpset and claset via addIffs;
  1390 
  1391   3) a tactic for record field splitting (record_split_tac) is part of
  1392 the standard claset (addSWrapper);
  1393 
  1394 To get a better idea about these rules you may retrieve them via
  1395 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1396 the name of your record type.
  1397 
  1398 The split tactic 3) conceptually simplifies by the following rule:
  1399 
  1400   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1401 
  1402 Thus any record variable that is bound by meta-all will automatically
  1403 blow up into some record constructor term, consequently the
  1404 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1405 solve record problems automatically.
  1406 
  1407 
  1408 * reorganized the main HOL image: HOL/Integ and String loaded by
  1409 default; theory Main includes everything;
  1410 
  1411 * automatic simplification of integer sums and comparisons, using cancellation;
  1412 
  1413 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1414 
  1415 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1416 
  1417 * many new identities for unions, intersections, set difference, etc.;
  1418 
  1419 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1420 called split_if, split_split, split_sum_case and split_nat_case (to go
  1421 with add/delsplits);
  1422 
  1423 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1424 (?x::unit) = (); this is made part of the default simpset, which COULD
  1425 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1426 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1427 unit_abs_eta_conv is added in order to counter the effect of
  1428 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1429 %u.f();
  1430 
  1431 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1432 makes more sense);
  1433 
  1434 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1435   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1436   disjointness reasoning but breaking a few old proofs.
  1437 
  1438 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1439 to 'converse' from 'inverse' (for compatibility with ZF and some
  1440 literature);
  1441 
  1442 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1443 the well-founded relation;
  1444 
  1445 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1446     Compl A.  The "Compl" syntax remains available as input syntax for this
  1447     release ONLY.
  1448 
  1449 * HOL/Update: new theory of function updates:
  1450     f(a:=b) == %x. if x=a then b else f x
  1451 may also be iterated as in f(a:=b,c:=d,...);
  1452 
  1453 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1454 
  1455 * HOL/List:
  1456   - new function list_update written xs[i:=v] that updates the i-th
  1457     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1458   - new function `upt' written [i..j(] which generates the list
  1459     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1460     bound write [i..j], which is a shorthand for [i..j+1(].
  1461   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1462 
  1463 * HOL/Arith:
  1464   - removed 'pred' (predecessor) function;
  1465   - generalized some theorems about n-1;
  1466   - many new laws about "div" and "mod";
  1467   - new laws about greatest common divisors (see theory ex/Primes);
  1468 
  1469 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1470 instead of "inverse";
  1471 
  1472 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1473   of the multiset ordering;
  1474 
  1475 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1476   (not included by default);
  1477 
  1478 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1479 
  1480 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1481   programs, i.e. different program variables may have different types.
  1482 
  1483 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1484   [previously, this check worked only if the rewrite rule was unconditional]
  1485   Now rew can involve either definitions or equalities (either == or =).
  1486 
  1487 
  1488 *** ZF ***
  1489 
  1490 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1491   only the theorems proved on ZF.ML;
  1492 
  1493 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1494   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1495   disjointness reasoning but breaking a few old proofs.
  1496 
  1497 * ZF/Update: new theory of function updates
  1498     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1499   may also be iterated as in f(a:=b,c:=d,...);
  1500 
  1501 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1502 
  1503 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1504   [previously, this check worked only if the rewrite rule was unconditional]
  1505   Now rew can involve either definitions or equalities (either == or =).
  1506 
  1507 * case_tac provided for compatibility with HOL
  1508     (like the old excluded_middle_tac, but with subgoals swapped)
  1509 
  1510 
  1511 *** Internal programming interfaces ***
  1512 
  1513 * Pure: several new basic modules made available for general use, see
  1514 also src/Pure/README;
  1515 
  1516 * improved the theory data mechanism to support encapsulation (data
  1517 kind name replaced by private Object.kind, acting as authorization
  1518 key); new type-safe user interface via functor TheoryDataFun; generic
  1519 print_data function becomes basically useless;
  1520 
  1521 * removed global_names compatibility flag -- all theory declarations
  1522 are qualified by default;
  1523 
  1524 * module Pure/Syntax now offers quote / antiquote translation
  1525 functions (useful for Hoare logic etc. with implicit dependencies);
  1526 see HOL/ex/Antiquote for an example use;
  1527 
  1528 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1529 cterm -> thm;
  1530 
  1531 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1532 subgoal;
  1533 
  1534 * Display.print_goals function moved to Locale.print_goals;
  1535 
  1536 * standard print function for goals supports current_goals_markers
  1537 variable for marking begin of proof, end of proof, start of goal; the
  1538 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1539 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1540 for example;
  1541 
  1542 
  1543 
  1544 New in Isabelle98 (January 1998)
  1545 --------------------------------
  1546 
  1547 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1548 
  1549 * changed lexical syntax of terms / types: dots made part of long
  1550 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1551 
  1552 * simpset (and claset) reference variable replaced by functions
  1553 simpset / simpset_ref;
  1554 
  1555 * no longer supports theory aliases (via merge) and non-trivial
  1556 implicit merge of thms' signatures;
  1557 
  1558 * most internal names of constants changed due to qualified names;
  1559 
  1560 * changed Pure/Sequence interface (see Pure/seq.ML);
  1561 
  1562 
  1563 *** General Changes ***
  1564 
  1565 * hierachically structured name spaces (for consts, types, axms, thms
  1566 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1567 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1568 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1569 long_names for fully qualified output names; NOTE: ML programs
  1570 (special tactics, packages etc.) referring to internal names may have
  1571 to be adapted to cope with fully qualified names; in case of severe
  1572 backward campatibility problems try setting 'global_names' at compile
  1573 time to have enrything declared within a flat name space; one may also
  1574 fine tune name declarations in theories via the 'global' and 'local'
  1575 section;
  1576 
  1577 * reimplemented the implicit simpset and claset using the new anytype
  1578 data filed in signatures; references simpset:simpset ref etc. are
  1579 replaced by functions simpset:unit->simpset and
  1580 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1581 to patch your ML files accordingly;
  1582 
  1583 * HTML output now includes theory graph data for display with Java
  1584 applet or isatool browser; data generated automatically via isatool
  1585 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1586 
  1587 * defs may now be conditional; improved rewrite_goals_tac to handle
  1588 conditional equations;
  1589 
  1590 * defs now admits additional type arguments, using TYPE('a) syntax;
  1591 
  1592 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1593 creates a new theory node; implicit merge of thms' signatures is
  1594 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1595 transfer:theory->thm->thm in (rare) cases;
  1596 
  1597 * improved handling of draft signatures / theories; draft thms (and
  1598 ctyps, cterms) are automatically promoted to real ones;
  1599 
  1600 * slightly changed interfaces for oracles: admit many per theory, named
  1601 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1602 
  1603 * print_goals: optional output of const types (set show_consts and
  1604 show_types);
  1605 
  1606 * improved output of warnings (###) and errors (***);
  1607 
  1608 * subgoal_tac displays a warning if the new subgoal has type variables;
  1609 
  1610 * removed old README and Makefiles;
  1611 
  1612 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1613 
  1614 * removed obsolete init_pps and init_database;
  1615 
  1616 * deleted the obsolete tactical STATE, which was declared by
  1617     fun STATE tacfun st = tacfun st st;
  1618 
  1619 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1620 (which abbreviates $HOME);
  1621 
  1622 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1623 use isatool fixseq to adapt your ML programs (this works for fully
  1624 qualified references to the Sequence structure only!);
  1625 
  1626 * use_thy no longer requires writable current directory; it always
  1627 reloads .ML *and* .thy file, if either one is out of date;
  1628 
  1629 
  1630 *** Classical Reasoner ***
  1631 
  1632 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1633 tactics that use classical reasoning to simplify a subgoal without
  1634 splitting it into several subgoals;
  1635 
  1636 * Safe_tac: like safe_tac but uses the default claset;
  1637 
  1638 
  1639 *** Simplifier ***
  1640 
  1641 * added simplification meta rules:
  1642     (asm_)(full_)simplify: simpset -> thm -> thm;
  1643 
  1644 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1645 logics (again);
  1646 
  1647 * added prems argument to simplification procedures;
  1648 
  1649 * HOL, FOL, ZF: added infix function `addsplits':
  1650   instead of `<simpset> setloop (split_tac <thms>)'
  1651   you can simply write `<simpset> addsplits <thms>'
  1652 
  1653 
  1654 *** Syntax ***
  1655 
  1656 * TYPE('a) syntax for type reflection terms;
  1657 
  1658 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1659 
  1660 * pretty printer: changed order of mixfix annotation preference (again!);
  1661 
  1662 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1663 
  1664 
  1665 *** HOL ***
  1666 
  1667 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1668   with `addloop' of the simplifier to faciliate case splitting in premises.
  1669 
  1670 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1671 
  1672 * HOL/Auth: new protocol proofs including some for the Internet
  1673   protocol TLS;
  1674 
  1675 * HOL/Map: new theory of `maps' a la VDM;
  1676 
  1677 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1678 cancelling out common nat summands from =, <, <= (in)equalities, or
  1679 differences; simplification procedures nat_cancel_factor for
  1680 cancelling common factor from =, <, <= (in)equalities over natural
  1681 sums; nat_cancel contains both kinds of procedures, it is installed by
  1682 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1683 
  1684 * HOL/simplifier: terms of the form
  1685   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1686   are rewritten to
  1687   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1688   and those of the form
  1689   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1690   are rewritten to
  1691   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1692 
  1693 * HOL/datatype
  1694   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1695 
  1696   P(t_case f1 ... fn x) =
  1697      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1698         ...
  1699        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1700      )
  1701 
  1702   and a theorem `split_t_case_asm' of the form
  1703 
  1704   P(t_case f1 ... fn x) =
  1705     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1706         ...
  1707        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1708      )
  1709   which can be added to a simpset via `addsplits'. The existing theorems
  1710   expand_list_case and expand_option_case have been renamed to
  1711   split_list_case and split_option_case.
  1712 
  1713 * HOL/Arithmetic:
  1714   - `pred n' is automatically converted to `n-1'.
  1715     Users are strongly encouraged not to use `pred' any longer,
  1716     because it will disappear altogether at some point.
  1717   - Users are strongly encouraged to write "0 < n" rather than
  1718     "n ~= 0". Theorems and proof tools have been modified towards this
  1719     `standard'.
  1720 
  1721 * HOL/Lists:
  1722   the function "set_of_list" has been renamed "set" (and its theorems too);
  1723   the function "nth" now takes its arguments in the reverse order and
  1724   has acquired the infix notation "!" as in "xs!n".
  1725 
  1726 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1727 
  1728 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1729   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1730 
  1731 * HOL/record: extensible records with schematic structural subtyping
  1732 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1733 still lacks various theorems and concrete record syntax;
  1734 
  1735 
  1736 *** HOLCF ***
  1737 
  1738 * removed "axioms" and "generated by" sections;
  1739 
  1740 * replaced "ops" section by extended "consts" section, which is capable of
  1741   handling the continuous function space "->" directly;
  1742 
  1743 * domain package:
  1744   . proves theorems immediately and stores them in the theory,
  1745   . creates hierachical name space,
  1746   . now uses normal mixfix annotations (instead of cinfix...),
  1747   . minor changes to some names and values (for consistency),
  1748   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1749   . separator between mutual domain defs: changed "," to "and",
  1750   . improved handling of sort constraints;  now they have to
  1751     appear on the left-hand side of the equations only;
  1752 
  1753 * fixed LAM <x,y,zs>.b syntax;
  1754 
  1755 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1756 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1757 
  1758 
  1759 *** FOL and ZF ***
  1760 
  1761 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1762   with `addloop' of the simplifier to faciliate case splitting in premises.
  1763 
  1764 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1765 in HOL, they strip ALL and --> from proved theorems;
  1766 
  1767 
  1768 
  1769 New in Isabelle94-8 (May 1997)
  1770 ------------------------------
  1771 
  1772 *** General Changes ***
  1773 
  1774 * new utilities to build / run / maintain Isabelle etc. (in parts
  1775 still somewhat experimental); old Makefiles etc. still functional;
  1776 
  1777 * new 'Isabelle System Manual';
  1778 
  1779 * INSTALL text, together with ./configure and ./build scripts;
  1780 
  1781 * reimplemented type inference for greater efficiency, better error
  1782 messages and clean internal interface;
  1783 
  1784 * prlim command for dealing with lots of subgoals (an easier way of
  1785 setting goals_limit);
  1786 
  1787 
  1788 *** Syntax ***
  1789 
  1790 * supports alternative (named) syntax tables (parser and pretty
  1791 printer); internal interface is provided by add_modesyntax(_i);
  1792 
  1793 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1794 be used in conjunction with the Isabelle symbol font; uses the
  1795 "symbols" syntax table;
  1796 
  1797 * added token_translation interface (may translate name tokens in
  1798 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1799 the current print_mode); IMPORTANT: user print translation functions
  1800 are responsible for marking newly introduced bounds
  1801 (Syntax.mark_boundT);
  1802 
  1803 * token translations for modes "xterm" and "xterm_color" that display
  1804 names in bold, underline etc. or colors (which requires a color
  1805 version of xterm);
  1806 
  1807 * infixes may now be declared with names independent of their syntax;
  1808 
  1809 * added typed_print_translation (like print_translation, but may
  1810 access type of constant);
  1811 
  1812 
  1813 *** Classical Reasoner ***
  1814 
  1815 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1816 some limitations.  Blast_tac...
  1817   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1818   + ignores elimination rules that don't have the correct format
  1819         (the conclusion MUST be a formula variable)
  1820   + ignores types, which can make HOL proofs fail
  1821   + rules must not require higher-order unification, e.g. apply_type in ZF
  1822     [message "Function Var's argument not a bound variable" relates to this]
  1823   + its proof strategy is more general but can actually be slower
  1824 
  1825 * substitution with equality assumptions no longer permutes other
  1826 assumptions;
  1827 
  1828 * minor changes in semantics of addafter (now called addaltern); renamed
  1829 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1830 (and access functions for it);
  1831 
  1832 * improved combination of classical reasoner and simplifier:
  1833   + functions for handling clasimpsets
  1834   + improvement of addss: now the simplifier is called _after_ the
  1835     safe steps.
  1836   + safe variant of addss called addSss: uses safe simplifications
  1837     _during_ the safe steps. It is more complete as it allows multiple
  1838     instantiations of unknowns (e.g. with slow_tac).
  1839 
  1840 *** Simplifier ***
  1841 
  1842 * added interface for simplification procedures (functions that
  1843 produce *proven* rewrite rules on the fly, depending on current
  1844 redex);
  1845 
  1846 * ordering on terms as parameter (used for ordered rewriting);
  1847 
  1848 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1849 
  1850 * the solver is now split into a safe and an unsafe part.
  1851 This should be invisible for the normal user, except that the
  1852 functions setsolver and addsolver have been renamed to setSolver and
  1853 addSolver; added safe_asm_full_simp_tac;
  1854 
  1855 
  1856 *** HOL ***
  1857 
  1858 * a generic induction tactic `induct_tac' which works for all datatypes and
  1859 also for type `nat';
  1860 
  1861 * a generic case distinction tactic `exhaust_tac' which works for all
  1862 datatypes and also for type `nat';
  1863 
  1864 * each datatype comes with a function `size';
  1865 
  1866 * patterns in case expressions allow tuple patterns as arguments to
  1867 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1868 
  1869 * primrec now also works with type nat;
  1870 
  1871 * recdef: a new declaration form, allows general recursive functions to be
  1872 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1873 
  1874 * the constant for negation has been renamed from "not" to "Not" to
  1875 harmonize with FOL, ZF, LK, etc.;
  1876 
  1877 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1878 infinite lists;
  1879 
  1880 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1881 
  1882 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1883 problems in commutative rings, using axiomatic type classes for + and *;
  1884 
  1885 * more examples in HOL/MiniML and HOL/Auth;
  1886 
  1887 * more default rewrite rules for quantifiers, union/intersection;
  1888 
  1889 * a new constant `arbitrary == @x.False';
  1890 
  1891 * HOLCF/IOA replaces old HOL/IOA;
  1892 
  1893 * HOLCF changes: derived all rules and arities
  1894   + axiomatic type classes instead of classes
  1895   + typedef instead of faking type definitions
  1896   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1897   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1898   + eliminated the types void, one, tr
  1899   + use unit lift and bool lift (with translations) instead of one and tr
  1900   + eliminated blift from Lift3.thy (use Def instead of blift)
  1901   all eliminated rules are derived as theorems --> no visible changes ;
  1902 
  1903 
  1904 *** ZF ***
  1905 
  1906 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1907 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1908 as ZF_cs addSIs [equalityI];
  1909 
  1910 
  1911 
  1912 New in Isabelle94-7 (November 96)
  1913 ---------------------------------
  1914 
  1915 * allowing negative levels (as offsets) in prlev and choplev;
  1916 
  1917 * super-linear speedup for large simplifications;
  1918 
  1919 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1920 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1921 FAIL); can suppress it using the command Delsimps (ex_simps @
  1922 all_simps); De Morgan laws are also now included, by default;
  1923 
  1924 * improved printing of ==>  :  ~:
  1925 
  1926 * new object-logic "Sequents" adds linear logic, while replacing LK
  1927 and Modal (thanks to Sara Kalvala);
  1928 
  1929 * HOL/Auth: correctness proofs for authentication protocols;
  1930 
  1931 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1932 examples on HOL/Auth);
  1933 
  1934 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1935 the rewriter and classical reasoner simultaneously;
  1936 
  1937 * function uresult no longer returns theorems in "standard" format;
  1938 regain previous version by: val uresult = standard o uresult;
  1939 
  1940 
  1941 
  1942 New in Isabelle94-6
  1943 -------------------
  1944 
  1945 * oracles -- these establish an interface between Isabelle and trusted
  1946 external reasoners, which may deliver results as theorems;
  1947 
  1948 * proof objects (in particular record all uses of oracles);
  1949 
  1950 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1951 
  1952 * "constdefs" section in theory files;
  1953 
  1954 * "primrec" section (HOL) no longer requires names;
  1955 
  1956 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1957 
  1958 
  1959 
  1960 New in Isabelle94-5
  1961 -------------------
  1962 
  1963 * reduced space requirements;
  1964 
  1965 * automatic HTML generation from theories;
  1966 
  1967 * theory files no longer require "..." (quotes) around most types;
  1968 
  1969 * new examples, including two proofs of the Church-Rosser theorem;
  1970 
  1971 * non-curried (1994) version of HOL is no longer distributed;
  1972 
  1973 
  1974 
  1975 New in Isabelle94-4
  1976 -------------------
  1977 
  1978 * greatly reduced space requirements;
  1979 
  1980 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1981 
  1982 * searchable theorem database (see the section "Retrieving theorems" on
  1983 page 8 of the Reference Manual);
  1984 
  1985 * new examples, including Grabczewski's monumental case study of the
  1986 Axiom of Choice;
  1987 
  1988 * The previous version of HOL renamed to Old_HOL;
  1989 
  1990 * The new version of HOL (previously called CHOL) uses a curried syntax
  1991 for functions.  Application looks like f a b instead of f(a,b);
  1992 
  1993 * Mutually recursive inductive definitions finally work in HOL;
  1994 
  1995 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1996 translates to the operator "split";
  1997 
  1998 
  1999 
  2000 New in Isabelle94-3
  2001 -------------------
  2002 
  2003 * new infix operator, addss, allowing the classical reasoner to
  2004 perform simplification at each step of its search.  Example:
  2005         fast_tac (cs addss ss)
  2006 
  2007 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2008 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2009 look like (a,b) instead of <a,b>;
  2010 
  2011 * PLEASE NOTE: CHOL will eventually replace HOL!
  2012 
  2013 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2014 It translates to the operator "split".  A new theory of integers is available;
  2015 
  2016 * In ZF, integer numerals now denote two's-complement binary integers.
  2017 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2018 
  2019 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2020 of the Axiom of Choice;
  2021 
  2022 
  2023 
  2024 New in Isabelle94-2
  2025 -------------------
  2026 
  2027 * Significantly faster resolution;
  2028 
  2029 * the different sections in a .thy file can now be mixed and repeated
  2030 freely;
  2031 
  2032 * Database of theorems for FOL, HOL and ZF.  New
  2033 commands including qed, qed_goal and bind_thm store theorems in the database.
  2034 
  2035 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2036 a given theory (thms_of), or find out what theory a theorem was proved in
  2037 (theory_of_thm);
  2038 
  2039 * Bugs fixed in the inductive definition and datatype packages;
  2040 
  2041 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2042 and HOL_dup_cs obsolete;
  2043 
  2044 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2045 have been removed;
  2046 
  2047 * Simpler definition of function space in ZF;
  2048 
  2049 * new results about cardinal and ordinal arithmetic in ZF;
  2050 
  2051 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2052 types;
  2053 
  2054 
  2055 $Id$