NEWS
author wenzelm
Sat Nov 03 18:40:21 2001 +0100 (2001-11-03)
changeset 12034 4471077c4d4f
parent 12022 9c3377b133c0
child 12078 4eb8061286e5
permissions -rw-r--r--
* 'domain' package adapted to new-style theories, e.g. see
HOLCF/ex/Dnat.thy;
     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 * Pure: renamed "antecedent" case to "rule_context";
    66 
    67 * Pure: added 'corollary' command;
    68 
    69 * Pure: fixed 'token_translation' command;
    70 
    71 * Pure: removed obsolete 'exported' attribute;
    72 
    73 * Pure: dummy pattern "_" in is/let is now automatically lifted over
    74 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
    75 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
    76 
    77 * Pure: method 'atomize' presents local goal premises as object-level
    78 statements (atomic meta-level propositions); setup controlled via
    79 rewrite rules declarations of 'atomize' attribute; example
    80 application: 'induct' method with proper rule statements in improper
    81 proof *scripts*;
    82 
    83 * Provers: 'simplified' attribute may refer to explicit rules instead
    84 of full simplifier context; 'iff' attribute handles conditional rules;
    85 
    86 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
    87 
    88 * HOL: 'recdef' now fails on unfinished automated proofs, use
    89 "(permissive)" option to recover old behavior;
    90 
    91 * HOL: 'inductive' no longer features separate (collective) attributes
    92 for 'intros' (was found too confusing);
    93 
    94 
    95 
    96 *** HOL ***
    97 
    98 * HOL: moved over to sane numeral syntax; the new policy is as
    99 follows:
   100 
   101   - 0 and 1 are polymorphic constants, which are defined on any
   102   numeric type (nat, int, real etc.);
   103 
   104   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   105   binary representation internally;
   106 
   107   - type nat has special constructor Suc, and generally prefers Suc 0
   108   over 1::nat and Suc (Suc 0) over 2::nat;
   109 
   110 This change may cause significant INCOMPATIBILITIES; here are some
   111 hints on converting existing sources:
   112 
   113   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   114   entities, so expressions involving "-" (unary or binary minus) need
   115   to be spaced properly;
   116 
   117   - existing occurrences of "1" may need to be constraint "1::nat" or
   118   even replaced by Suc 0; similar for old "2";
   119 
   120   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   121 
   122   - remove all special provisions on numerals in proofs;
   123 
   124 * HOL/record:
   125   - removed old "make" and "make_scheme" operations -- INCOMPATIBILITY;
   126   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   127   - provides cases/induct rules for use with corresponding Isar methods;
   128   - new derived operations "make" (for adding fields of current
   129     record), "extend" to promote fixed record to record scheme, and
   130     "truncate" for the reverse; cf. theorems "derived_defs", which are
   131     *not* declared as simp by default;
   132   - internal definitions directly based on a light-weight abstract
   133     theory of product types over typedef rather than datatype;
   134 
   135 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   136 
   137 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   138 (beware of argument permutation!);
   139 
   140 * HOL: linorder_less_split superseded by linorder_cases;
   141 
   142 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   143 to peripheral theory "Hilbert_Choice";
   144 
   145 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   146 in this (rare) case use:
   147 
   148   delSWrapper "split_all_tac"
   149   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   150 
   151 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   152 MAY FAIL;
   153 
   154 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   155 Isabelle's type classes, ^ on functions and relations has too general
   156 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   157 necessary to attach explicit type constraints;
   158 
   159 * HOL: syntax translations now work properly with numerals and records
   160 expressions;
   161 
   162 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   163 Florian Kammüller;
   164 
   165 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   166 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   167 renamed "Product_Type.unit";
   168 
   169 
   170 *** HOLCF ***
   171 
   172 * proper rep_datatype lift (see theory Lift); use plain induct_tac
   173 instead of former lift.induct_tac; always use UU instead of Undef;
   174 
   175 * 'domain' package adapted to new-style theories, e.g. see
   176 HOLCF/ex/Dnat.thy;
   177 
   178 
   179 *** ZF ***
   180 
   181 * ZF: the integer library now covers quotients and remainders, with
   182 many laws relating division to addition, multiplication, etc.;
   183 
   184 
   185 *** General ***
   186 
   187 * kernel: meta-level proof terms (by Stefan Berghofer), see also ref
   188 manual;
   189 
   190 * Pure/axclass: removed obsolete ML interface goal_subclass/goal_arity;
   191 
   192 * classical: renamed addaltern to addafter, addSaltern to addSafter;
   193 
   194 * clasimp: ``iff'' declarations now handle conditional rules as well;
   195 
   196 * syntax: new token syntax "num" for plain numerals (without "#" of
   197 "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now separate
   198 tokens, so expressions involving minus need to be spaced properly;
   199 
   200 * syntax: support non-oriented infixes;
   201 
   202 * syntax: print modes "type_brackets" and "no_type_brackets" control
   203 output of nested => (types); the default behavior is "type_brackets";
   204 
   205 * syntax: builtin parse translation for "_constify" turns valued
   206 tokens into AST constants;
   207 
   208 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   209 
   210 * system: Proof General keywords specification is now part of the
   211 Isabelle distribution (see etc/isar-keywords.el);
   212 
   213 * system: smart selection of Isabelle process versus Isabelle
   214 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   215 run both "isabelle" and "Isabelle" even if file names are badly
   216 damaged (executable inspects the case of the first letter of its own
   217 name); added separate "isabelle-process" and "isabelle-interface";
   218 
   219 
   220 
   221 New in Isabelle99-2 (February 2001)
   222 -----------------------------------
   223 
   224 *** Overview of INCOMPATIBILITIES ***
   225 
   226 * HOL: please note that theories in the Library and elsewhere often use the
   227 new-style (Isar) format; to refer to their theorems in an ML script you must
   228 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   229 
   230 * HOL: inductive package no longer splits induction rule aggressively,
   231 but only as far as specified by the introductions given; the old
   232 format may be recovered via ML function complete_split_rule or attribute
   233 'split_rule (complete)';
   234 
   235 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   236 gfp_Tarski to gfp_unfold;
   237 
   238 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   239 
   240 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   241 relation); infix "^^" has been renamed "``"; infix "``" has been
   242 renamed "`"; "univalent" has been renamed "single_valued";
   243 
   244 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   245 operation;
   246 
   247 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   248 
   249 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   250 
   251 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   252 consequence, it is no longer monotonic wrt. the local goal context
   253 (which is now passed through the inductive cases);
   254 
   255 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   256 \<gg> to \<ggreater>;
   257 
   258 
   259 *** Document preparation ***
   260 
   261 * \isabellestyle{NAME} selects version of Isabelle output (currently
   262 available: are "it" for near math-mode best-style output, "sl" for
   263 slanted text style, and "tt" for plain type-writer; if no
   264 \isabellestyle command is given, output is according to slanted
   265 type-writer);
   266 
   267 * support sub/super scripts (for single symbols only), input syntax is
   268 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   269 
   270 * some more standard symbols; see Appendix A of the system manual for
   271 the complete list of symbols defined in isabellesym.sty;
   272 
   273 * improved isabelle style files; more abstract symbol implementation
   274 (should now use \isamath{...} and \isatext{...} in custom symbol
   275 definitions);
   276 
   277 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   278 state; Note that presentation of goal states does not conform to
   279 actual human-readable proof documents.  Please do not include goal
   280 states into document output unless you really know what you are doing!
   281 
   282 * proper indentation of antiquoted output with proportional LaTeX
   283 fonts;
   284 
   285 * no_document ML operator temporarily disables LaTeX document
   286 generation;
   287 
   288 * isatool unsymbolize tunes sources for plain ASCII communication;
   289 
   290 
   291 *** Isar ***
   292 
   293 * Pure: Isar now suffers initial goal statements to contain unbound
   294 schematic variables (this does not conform to actual readable proof
   295 documents, due to unpredictable outcome and non-compositional proof
   296 checking); users who know what they are doing may use schematic goals
   297 for Prolog-style synthesis of proven results;
   298 
   299 * Pure: assumption method (an implicit finishing) now handles actual
   300 rules as well;
   301 
   302 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   303 initial goal, declare "that" only as Pure intro (only for single
   304 steps); the "that" rule assumption may now be involved in implicit
   305 finishing, thus ".." becomes a feasible for trivial obtains;
   306 
   307 * Pure: default proof step now includes 'intro_classes'; thus trivial
   308 instance proofs may be performed by "..";
   309 
   310 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   311 statements as well;
   312 
   313 * Pure: more robust selection of calculational rules;
   314 
   315 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   316 rule (as well as the assumption rule);
   317 
   318 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   319 lemmas, using the graph browser tool;
   320 
   321 * Pure: predict failure of "show" in interactive mode;
   322 
   323 * Pure: 'thms_containing' now takes actual terms as arguments;
   324 
   325 * HOL: improved method 'induct' --- now handles non-atomic goals
   326 (potential INCOMPATIBILITY); tuned error handling;
   327 
   328 * HOL: cases and induct rules now provide explicit hints about the
   329 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   330 any remaining facts are inserted into the goal verbatim;
   331 
   332 * HOL: local contexts (aka cases) may now contain term bindings as
   333 well; the 'cases' and 'induct' methods new provide a ?case binding for
   334 the result to be shown in each case;
   335 
   336 * HOL: added 'recdef_tc' command;
   337 
   338 * isatool convert assists in eliminating legacy ML scripts;
   339 
   340 
   341 *** HOL ***
   342 
   343 * HOL/Library: a collection of generic theories to be used together
   344 with main HOL; the theory loader path already includes this directory
   345 by default; the following existing theories have been moved here:
   346 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   347 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   348 
   349 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   350 modelling and verification task performed in Isabelle/HOL +
   351 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   352 
   353 * HOL/Algebra: special summation operator SUM no longer exists, it has
   354 been replaced by setsum; infix 'assoc' now has priority 50 (like
   355 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   356 'domain', this makes the theory consistent with mathematical
   357 literature;
   358 
   359 * HOL basics: added overloaded operations "inverse" and "divide"
   360 (infix "/"), syntax for generic "abs" operation, generic summation
   361 operator \<Sum>;
   362 
   363 * HOL/typedef: simplified package, provide more useful rules (see also
   364 HOL/subset.thy);
   365 
   366 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   367 now expressed as a proper nested rule (old-style tactic scripts may
   368 require atomize_strip_tac to cope with non-atomic premises);
   369 
   370 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   371 to "split_conv" (old name still available for compatibility);
   372 
   373 * HOL: improved concrete syntax for strings (e.g. allows translation
   374 rules with string literals);
   375 
   376 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   377 and Fleuriot's mechanization of analysis;
   378 
   379 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   380 
   381 
   382 *** CTT ***
   383 
   384 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   385 "lam" is displayed as TWO lambda-symbols
   386 
   387 * CTT: theory Main now available, containing everything (that is, Bool
   388 and Arith);
   389 
   390 
   391 *** General ***
   392 
   393 * Pure: the Simplifier has been implemented properly as a derived rule
   394 outside of the actual kernel (at last!); the overall performance
   395 penalty in practical applications is about 50%, while reliability of
   396 the Isabelle inference kernel has been greatly improved;
   397 
   398 * print modes "brackets" and "no_brackets" control output of nested =>
   399 (types) and ==> (props); the default behaviour is "brackets";
   400 
   401 * Provers: fast_tac (and friends) now handle actual object-logic rules
   402 as assumptions as well;
   403 
   404 * system: support Poly/ML 4.0;
   405 
   406 * system: isatool install handles KDE version 1 or 2;
   407 
   408 
   409 
   410 New in Isabelle99-1 (October 2000)
   411 ----------------------------------
   412 
   413 *** Overview of INCOMPATIBILITIES ***
   414 
   415 * HOL: simplification of natural numbers is much changed; to partly
   416 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   417 issue the following ML commands:
   418 
   419   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   420   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   421 
   422 * HOL: simplification no longer dives into case-expressions; this is
   423 controlled by "t.weak_case_cong" for each datatype t;
   424 
   425 * HOL: nat_less_induct renamed to less_induct;
   426 
   427 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   428 fixsome to patch .thy and .ML sources automatically;
   429 
   430   select_equality  -> some_equality
   431   select_eq_Ex     -> some_eq_ex
   432   selectI2EX       -> someI2_ex
   433   selectI2         -> someI2
   434   selectI          -> someI
   435   select1_equality -> some1_equality
   436   Eps_sym_eq       -> some_sym_eq_trivial
   437   Eps_eq           -> some_eq_trivial
   438 
   439 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   440 
   441 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   442 instead);
   443 
   444 * HOL: the recursion equations generated by 'recdef' are now called
   445 f.simps instead of f.rules;
   446 
   447 * HOL: qed_spec_mp now also handles bounded ALL as well;
   448 
   449 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   450 sometimes be needed;
   451 
   452 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   453 
   454 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   455 
   456 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   457 product is now "<*>" instead of "Times"; the lexicographic product is
   458 now "<*lex*>" instead of "**";
   459 
   460 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   461 of main HOL, but was unused); better use HOL's datatype package;
   462 
   463 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   464 the old syntax may be recovered as follows:
   465 
   466   syntax (symbols)
   467     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   468       (infixl "\\<oplus>" 100)
   469 
   470 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   471 
   472 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   473 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   474 internally;
   475 
   476 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   477 changed from A/r to A//r;
   478 
   479 * ZF: new treatment of arithmetic (nat & int) may break some old
   480 proofs;
   481 
   482 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   483 rulify -> rule_format, elimify -> elim_format, ...);
   484 
   485 * Isar/Provers: intro/elim/dest attributes changed; renamed
   486 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   487 should have to change intro!! to intro? only); replaced "delrule" by
   488 "rule del";
   489 
   490 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   491 
   492 * Provers: strengthened force_tac by using new first_best_tac;
   493 
   494 * LaTeX document preparation: several changes of isabelle.sty (see
   495 lib/texinputs);
   496 
   497 
   498 *** Document preparation ***
   499 
   500 * formal comments (text blocks etc.) in new-style theories may now
   501 contain antiquotations of thm/prop/term/typ/text to be presented
   502 according to latex print mode; concrete syntax is like this:
   503 @{term[show_types] "f(x) = a + x"};
   504 
   505 * isatool mkdir provides easy setup of Isabelle session directories,
   506 including proper document sources;
   507 
   508 * generated LaTeX sources are now deleted after successful run
   509 (isatool document -c); may retain a copy somewhere else via -D option
   510 of isatool usedir;
   511 
   512 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   513 style files, achieving self-contained LaTeX sources and simplifying
   514 LaTeX debugging;
   515 
   516 * old-style theories now produce (crude) LaTeX output as well;
   517 
   518 * browser info session directories are now self-contained (may be put
   519 on WWW server seperately); improved graphs of nested sessions; removed
   520 graph for 'all sessions';
   521 
   522 * several improvements in isabelle style files; \isabellestyle{it}
   523 produces fake math mode output; \isamarkupheader is now \section by
   524 default; see lib/texinputs/isabelle.sty etc.;
   525 
   526 
   527 *** Isar ***
   528 
   529 * Isar/Pure: local results and corresponding term bindings are now
   530 subject to Hindley-Milner polymorphism (similar to ML); this
   531 accommodates incremental type-inference very nicely;
   532 
   533 * Isar/Pure: new derived language element 'obtain' supports
   534 generalized existence reasoning;
   535 
   536 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   537 support accumulation of results, without applying any rules yet;
   538 useful to collect intermediate results without explicit name
   539 references, and for use with transitivity rules with more than 2
   540 premises;
   541 
   542 * Isar/Pure: scalable support for case-analysis type proofs: new
   543 'case' language element refers to local contexts symbolically, as
   544 produced by certain proof methods; internally, case names are attached
   545 to theorems as "tags";
   546 
   547 * Isar/Pure: theory command 'hide' removes declarations from
   548 class/type/const name spaces;
   549 
   550 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   551 indicate potential overloading;
   552 
   553 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   554 
   555 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   556 "{a,b,c}" instead of {a,b,c};
   557 
   558 * Isar/Pure now provides its own version of intro/elim/dest
   559 attributes; useful for building new logics, but beware of confusion
   560 with the version in Provers/classical;
   561 
   562 * Isar/Pure: the local context of (non-atomic) goals is provided via
   563 case name 'antecedent';
   564 
   565 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   566 to the current context is now done automatically);
   567 
   568 * Isar/Pure: theory command 'method_setup' provides a simple interface
   569 for definining proof methods in ML;
   570 
   571 * Isar/Provers: intro/elim/dest attributes changed; renamed
   572 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   573 most cases, one should have to change intro!! to intro? only);
   574 replaced "delrule" by "rule del";
   575 
   576 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   577 'symmetric' attribute (the latter supercedes [RS sym]);
   578 
   579 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   580 method modifier); 'simp' method: 'only:' modifier removes loopers as
   581 well (including splits);
   582 
   583 * Isar/Provers: Simplifier and Classical methods now support all kind
   584 of modifiers used in the past, including 'cong', 'iff', etc.
   585 
   586 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   587 of Simplifier and Classical reasoner);
   588 
   589 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   590 now support named cases; major packages (inductive, datatype, primrec,
   591 recdef) support case names and properly name parameters;
   592 
   593 * Isar/HOL: new transitivity rules for substitution in inequalities --
   594 monotonicity conditions are extracted to be proven at end of
   595 calculations;
   596 
   597 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   598 method anyway;
   599 
   600 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   601 split_if split_if_asm; datatype package provides theorems foo.splits =
   602 foo.split foo.split_asm for each datatype;
   603 
   604 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   605 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   606 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   607 use "(cases (simplified))" method in proper proof texts);
   608 
   609 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   610 
   611 * Isar: names of theorems etc. may be natural numbers as well;
   612 
   613 * Isar: 'pr' command: optional arguments for goals_limit and
   614 ProofContext.prems_limit; no longer prints theory contexts, but only
   615 proof states;
   616 
   617 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   618 additional print modes to be specified; e.g. "pr(latex)" will print
   619 proof state according to the Isabelle LaTeX style;
   620 
   621 * Isar: improved support for emulating tactic scripts, including proof
   622 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   623 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   624 (for HOL datatypes);
   625 
   626 * Isar: simplified (more robust) goal selection of proof methods: 1st
   627 goal, all goals, or explicit goal specifier (tactic emulation); thus
   628 'proof method scripts' have to be in depth-first order;
   629 
   630 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   631 
   632 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   633 should instead use individual commands for printing items
   634 (print_commands, print_methods etc.);
   635 
   636 * Isar: added 'nothing' --- the empty list of theorems;
   637 
   638 
   639 *** HOL ***
   640 
   641 * HOL/MicroJava: formalization of a fragment of Java, together with a
   642 corresponding virtual machine and a specification of its bytecode
   643 verifier and a lightweight bytecode verifier, including proofs of
   644 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   645 Cornelia Pusch (see also the homepage of project Bali at
   646 http://isabelle.in.tum.de/Bali/);
   647 
   648 * HOL/Algebra: new theory of rings and univariate polynomials, by
   649 Clemens Ballarin;
   650 
   651 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   652 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   653 Rasmussen;
   654 
   655 * HOL/Lattice: fundamental concepts of lattice theory and order
   656 structures, including duals, properties of bounds versus algebraic
   657 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   658 Theorem for complete lattices etc.; may also serve as a demonstration
   659 for abstract algebraic reasoning using axiomatic type classes, and
   660 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   661 
   662 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   663 von Oheimb;
   664 
   665 * HOL/IMPP: extension of IMP with local variables and mutually
   666 recursive procedures, by David von Oheimb;
   667 
   668 * HOL/Lambda: converted into new-style theory and document;
   669 
   670 * HOL/ex/Multiquote: example of multiple nested quotations and
   671 anti-quotations -- basically a generalized version of de-Bruijn
   672 representation; very useful in avoiding lifting of operations;
   673 
   674 * HOL/record: added general record equality rule to simpset; fixed
   675 select-update simplification procedure to handle extended records as
   676 well; admit "r" as field name;
   677 
   678 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   679 other numeric types and also as the identity of groups, rings, etc.;
   680 
   681 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   682 Types nat and int belong to this axclass;
   683 
   684 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   685    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   686    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   687   two terms #m*u and #n*u are replaced by #(m+n)*u
   688     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   689   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   690     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   691 
   692 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   693 powerful prover for predicate logic but knows nothing of clasets; see
   694 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   695 
   696 * HOL: new version of "case_tac" subsumes both boolean case split and
   697 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   698 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   699 
   700 * HOL: simplification no longer dives into case-expressions: only the
   701 selector expression is simplified, but not the remaining arms; to
   702 enable full simplification of case-expressions for datatype t, you may
   703 remove t.weak_case_cong from the simpset, either globally (Delcongs
   704 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   705 
   706 * HOL/recdef: the recursion equations generated by 'recdef' for
   707 function 'f' are now called f.simps instead of f.rules; if all
   708 termination conditions are proved automatically, these simplification
   709 rules are added to the simpset, as in primrec; rules may be named
   710 individually as well, resulting in a separate list of theorems for
   711 each equation;
   712 
   713 * HOL/While is a new theory that provides a while-combinator. It
   714 permits the definition of tail-recursive functions without the
   715 provision of a termination measure. The latter is necessary once the
   716 invariant proof rule for while is applied.
   717 
   718 * HOL: new (overloaded) notation for the set of elements below/above
   719 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   720 
   721 * HOL: theorems impI, allI, ballI bound as "strip";
   722 
   723 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   724 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   725 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   726 
   727 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   728 
   729 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   730 main HOL, but was unused);
   731 
   732 * HOL: fewer consts declared as global (e.g. have to refer to
   733 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   734 
   735 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   736 in case of overlap with user translations (e.g. judgements over
   737 tuples); (note that the underlying logical represenation is still
   738 bogus);
   739 
   740 
   741 *** ZF ***
   742 
   743 * ZF: simplification automatically cancels common terms in arithmetic
   744 expressions over nat and int;
   745 
   746 * ZF: new treatment of nat to minimize type-checking: all operators
   747 coerce their operands to a natural number using the function natify,
   748 making the algebraic laws unconditional;
   749 
   750 * ZF: as above, for int: operators coerce their operands to an integer
   751 using the function intify;
   752 
   753 * ZF: the integer library now contains many of the usual laws for the
   754 orderings, including $<=, and monotonicity laws for $+ and $*;
   755 
   756 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   757 simplification;
   758 
   759 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   760 to the simplifier and classical reasoner simultaneously;
   761 
   762 
   763 *** General ***
   764 
   765 * Provers: blast_tac now handles actual object-logic rules as
   766 assumptions; note that auto_tac uses blast_tac internally as well;
   767 
   768 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   769 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   770 
   771 * Provers: delrules now handles destruct rules as well (no longer need
   772 explicit make_elim);
   773 
   774 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   775   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   776 use instead the strong form,
   777   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   778 in HOL, FOL and ZF the function cla_make_elim will create such rules
   779 from destruct-rules;
   780 
   781 * Provers: Simplifier.easy_setup provides a fast path to basic
   782 Simplifier setup for new object-logics;
   783 
   784 * Pure: AST translation rules no longer require constant head on LHS;
   785 
   786 * Pure: improved name spaces: ambiguous output is qualified; support
   787 for hiding of names;
   788 
   789 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   790 XSYMBOL_HOME; no longer need to do manual configuration in most
   791 situations;
   792 
   793 * system: compression of ML heaps images may now be controlled via -c
   794 option of isabelle and isatool usedir (currently only observed by
   795 Poly/ML);
   796 
   797 * system: isatool installfonts may handle X-Symbol fonts as well (very
   798 useful for remote X11);
   799 
   800 * system: provide TAGS file for Isabelle sources;
   801 
   802 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   803 order;
   804 
   805 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   806 timing flag supersedes proof_timing and Toplevel.trace;
   807 
   808 * ML: new combinators |>> and |>>> for incremental transformations
   809 with secondary results (e.g. certain theory extensions):
   810 
   811 * ML: PureThy.add_defs gets additional argument to indicate potential
   812 overloading (usually false);
   813 
   814 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   815 results;
   816 
   817 
   818 
   819 New in Isabelle99 (October 1999)
   820 --------------------------------
   821 
   822 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   823 
   824 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   825 are no longer simplified.  (This allows the simplifier to unfold recursive
   826 functional programs.)  To restore the old behaviour, declare
   827 
   828     Delcongs [if_weak_cong];
   829 
   830 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   831 complement;
   832 
   833 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   834 
   835 * HOL/datatype: mutual_induct_tac no longer exists --
   836   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   837 
   838 * HOL/typedef: fixed type inference for representing set; type
   839 arguments now have to occur explicitly on the rhs as type constraints;
   840 
   841 * ZF: The con_defs part of an inductive definition may no longer refer
   842 to constants declared in the same theory;
   843 
   844 * HOL, ZF: the function mk_cases, generated by the inductive
   845 definition package, has lost an argument.  To simplify its result, it
   846 uses the default simpset instead of a supplied list of theorems.
   847 
   848 * HOL/List: the constructors of type list are now Nil and Cons;
   849 
   850 * Simplifier: the type of the infix ML functions
   851         setSSolver addSSolver setSolver addSolver
   852 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   853 for packaging solvers. A solver is created via
   854         mk_solver: string -> (thm list -> int -> tactic) -> solver
   855 where the string argument is only a comment.
   856 
   857 
   858 *** Proof tools ***
   859 
   860 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   861 decision procedure for linear arithmetic. Currently it is used for
   862 types `nat', `int', and `real' in HOL (see below); it can, should and
   863 will be instantiated for other types and logics as well.
   864 
   865 * The simplifier now accepts rewrite rules with flexible heads, eg
   866      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   867   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   868   matching.
   869 
   870 
   871 *** General ***
   872 
   873 * New Isabelle/Isar subsystem provides an alternative to traditional
   874 tactical theorem proving; together with the ProofGeneral/isar user
   875 interface it offers an interactive environment for developing human
   876 readable proof documents (Isar == Intelligible semi-automated
   877 reasoning); for further information see isatool doc isar-ref,
   878 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   879 
   880 * improved and simplified presentation of theories: better HTML markup
   881 (including colors), graph views in several sizes; isatool usedir now
   882 provides a proper interface for user theories (via -P option); actual
   883 document preparation based on (PDF)LaTeX is available as well (for
   884 new-style theories only); see isatool doc system for more information;
   885 
   886 * native support for Proof General, both for classic Isabelle and
   887 Isabelle/Isar;
   888 
   889 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   890 using the graph browser tool;
   891 
   892 * Isabelle manuals now also available as PDF;
   893 
   894 * theory loader rewritten from scratch (may not be fully
   895 bug-compatible); old loadpath variable has been replaced by show_path,
   896 add_path, del_path, reset_path functions; new operations such as
   897 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   898 isatool doc ref);
   899 
   900 * improved isatool install: option -k creates KDE application icon,
   901 option -p DIR installs standalone binaries;
   902 
   903 * added ML_PLATFORM setting (useful for cross-platform installations);
   904 more robust handling of platform specific ML images for SML/NJ;
   905 
   906 * the settings environment is now statically scoped, i.e. it is never
   907 created again in sub-processes invoked from isabelle, isatool, or
   908 Isabelle;
   909 
   910 * path element specification '~~' refers to '$ISABELLE_HOME';
   911 
   912 * in locales, the "assumes" and "defines" parts may be omitted if
   913 empty;
   914 
   915 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   916 long arrows);
   917 
   918 * new print_mode "HTML";
   919 
   920 * new flag show_tags controls display of tags of theorems (which are
   921 basically just comments that may be attached by some tools);
   922 
   923 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   924 mode and goal output format:
   925 
   926 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   927 244c244
   928 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   929 ---
   930 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   931 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   932 181c181
   933 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   934 ---
   935 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   936 
   937 * function bind_thms stores lists of theorems (cf. bind_thm);
   938 
   939 * new shorthand tactics ftac, eatac, datac, fatac;
   940 
   941 * qed (and friends) now accept "" as result name; in that case the
   942 theorem is not stored, but proper checks and presentation of the
   943 result still apply;
   944 
   945 * theorem database now also indexes constants "Trueprop", "all",
   946 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   947 
   948 
   949 *** HOL ***
   950 
   951 ** HOL arithmetic **
   952 
   953 * There are now decision procedures for linear arithmetic over nat and
   954 int:
   955 
   956 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   957 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   958 are treated as atomic; subformulae not involving type `nat' or `int'
   959 are ignored; quantified subformulae are ignored unless they are
   960 positive universal or negative existential. The tactic has to be
   961 invoked by hand and can be a little bit slow. In particular, the
   962 running time is exponential in the number of occurrences of `min' and
   963 `max', and `-' on `nat'.
   964 
   965 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   966 (negated) (in)equalities among the premises and the conclusion into
   967 account (i.e. no compound formulae) and does not know about `min' and
   968 `max', and `-' on `nat'. It is fast and is used automatically by the
   969 simplifier.
   970 
   971 NB: At the moment, these decision procedures do not cope with mixed
   972 nat/int formulae where the two parts interact, such as `m < n ==>
   973 int(m) < int(n)'.
   974 
   975 * HOL/Numeral provides a generic theory of numerals (encoded
   976 efficiently as bit strings); setup for types nat/int/real is in place;
   977 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   978 int, existing theories and proof scripts may require a few additional
   979 type constraints;
   980 
   981 * integer division and remainder can now be performed on constant
   982 arguments;
   983 
   984 * many properties of integer multiplication, division and remainder
   985 are now available;
   986 
   987 * An interface to the Stanford Validity Checker (SVC) is available through the
   988 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   989 are proved automatically.  SVC must be installed separately, and its results
   990 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   991 invocation of the underlying oracle).  For SVC see
   992   http://verify.stanford.edu/SVC
   993 
   994 * IsaMakefile: the HOL-Real target now builds an actual image;
   995 
   996 
   997 ** HOL misc **
   998 
   999 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1000 (in Isabelle/Isar) -- by Gertrud Bauer;
  1001 
  1002 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1003 analysis for assembly languages with subtypes;
  1004 
  1005 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1006 -- avoids syntactic ambiguities and treats state, transition, and
  1007 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1008 changed syntax and (many) tactics;
  1009 
  1010 * HOL/inductive: Now also handles more general introduction rules such
  1011   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1012   theorems are now maintained within the theory (maintained via the
  1013   "mono" attribute);
  1014 
  1015 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1016   (using function types) such as
  1017 
  1018   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1019 
  1020 * HOL/record: record_simproc (part of the default simpset) takes care
  1021 of selectors applied to updated records; record_split_tac is no longer
  1022 part of the default claset; update_defs may now be removed from the
  1023 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1024 
  1025   claset_ref () := claset() addSWrapper record_split_wrapper;
  1026   Delsimprocs [record_simproc]
  1027 
  1028 * HOL/typedef: fixed type inference for representing set; type
  1029 arguments now have to occur explicitly on the rhs as type constraints;
  1030 
  1031 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1032 names rather than an ML expression;
  1033 
  1034 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1035 supplied later.  Program schemes can be defined, such as
  1036     "While B C s = (if B s then While B C (C s) else s)"
  1037 where the well-founded relation can be chosen after B and C have been given.
  1038 
  1039 * HOL/List: the constructors of type list are now Nil and Cons;
  1040 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1041 course, ML tools referring to List.list.op # etc. have to be adapted;
  1042 
  1043 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1044 disabled by default; run isabelle with option -m HOL to get back to
  1045 the original Gordon/HOL-style output;
  1046 
  1047 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1048 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1049 
  1050 * HOL basic syntax simplified (more orthogonal): all variants of
  1051 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1052 Eps operator is provided as well: "SOME x. P[x]";
  1053 
  1054 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1055 
  1056 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1057 thus available for user theories;
  1058 
  1059 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1060 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1061 time;
  1062 
  1063 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1064 several times and then mp;
  1065 
  1066 
  1067 *** LK ***
  1068 
  1069 * the notation <<...>> is now available as a notation for sequences of
  1070 formulas;
  1071 
  1072 * the simplifier is now installed
  1073 
  1074 * the axiom system has been generalized (thanks to Soren Heilmann)
  1075 
  1076 * the classical reasoner now has a default rule database
  1077 
  1078 
  1079 *** ZF ***
  1080 
  1081 * new primrec section allows primitive recursive functions to be given
  1082 directly (as in HOL) over datatypes and the natural numbers;
  1083 
  1084 * new tactics induct_tac and exhaust_tac for induction (or case
  1085 analysis) over datatypes and the natural numbers;
  1086 
  1087 * the datatype declaration of type T now defines the recursor T_rec;
  1088 
  1089 * simplification automatically does freeness reasoning for datatype
  1090 constructors;
  1091 
  1092 * automatic type-inference, with AddTCs command to insert new
  1093 type-checking rules;
  1094 
  1095 * datatype introduction rules are now added as Safe Introduction rules
  1096 to the claset;
  1097 
  1098 * the syntax "if P then x else y" is now available in addition to
  1099 if(P,x,y);
  1100 
  1101 
  1102 *** Internal programming interfaces ***
  1103 
  1104 * tuned simplifier trace output; new flag debug_simp;
  1105 
  1106 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1107 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1108 
  1109 * AxClass.axclass_tac lost the theory argument;
  1110 
  1111 * tuned current_goals_markers semantics: begin / end goal avoids
  1112 printing empty lines;
  1113 
  1114 * removed prs and prs_fn hook, which was broken because it did not
  1115 include \n in its semantics, forcing writeln to add one
  1116 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1117 string -> unit if you really want to output text without newline;
  1118 
  1119 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1120 plain output, interface builders may have to enable 'isabelle_font'
  1121 mode to get Isabelle font glyphs as before;
  1122 
  1123 * refined token_translation interface; INCOMPATIBILITY: output length
  1124 now of type real instead of int;
  1125 
  1126 * theory loader actions may be traced via new ThyInfo.add_hook
  1127 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1128 your own database of information attached to *whole* theories -- as
  1129 opposed to intra-theory data slots offered via TheoryDataFun;
  1130 
  1131 * proper handling of dangling sort hypotheses (at last!);
  1132 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1133 extra sort hypotheses that can be witnessed from the type signature;
  1134 the force_strip_shyps flag is gone, any remaining shyps are simply
  1135 left in the theorem (with a warning issued by strip_shyps_warning);
  1136 
  1137 
  1138 
  1139 New in Isabelle98-1 (October 1998)
  1140 ----------------------------------
  1141 
  1142 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1143 
  1144 * several changes of automated proof tools;
  1145 
  1146 * HOL: major changes to the inductive and datatype packages, including
  1147 some minor incompatibilities of theory syntax;
  1148 
  1149 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1150 called `inj_on';
  1151 
  1152 * HOL: removed duplicate thms in Arith:
  1153   less_imp_add_less  should be replaced by  trans_less_add1
  1154   le_imp_add_le      should be replaced by  trans_le_add1
  1155 
  1156 * HOL: unary minus is now overloaded (new type constraints may be
  1157 required);
  1158 
  1159 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1160 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1161 now taken as an integer constant.
  1162 
  1163 * Pure: ML function 'theory_of' renamed to 'theory';
  1164 
  1165 
  1166 *** Proof tools ***
  1167 
  1168 * Simplifier:
  1169   1. Asm_full_simp_tac is now more aggressive.
  1170      1. It will sometimes reorient premises if that increases their power to
  1171         simplify.
  1172      2. It does no longer proceed strictly from left to right but may also
  1173         rotate premises to achieve further simplification.
  1174      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1175      old Asm_full_simp_tac in that it does not rotate premises.
  1176   2. The simplifier now knows a little bit about nat-arithmetic.
  1177 
  1178 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1179 allows for selected deletion of wrappers, by introduction of names for
  1180 wrapper functionals.  This implies that addbefore, addSbefore,
  1181 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1182 and that adding two tactics with the same name overwrites the first
  1183 one (emitting a warning).
  1184   type wrapper = (int -> tactic) -> (int -> tactic)
  1185   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1186   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1187   delWrapper, delSWrapper: claset *  string            -> claset
  1188   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1189 
  1190 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1191 semantics; addbefore now affects only the unsafe part of step_tac
  1192 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1193 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1194 by Force_tac;
  1195 
  1196 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1197 compWrapper; added safe wrapper (and access functions for it);
  1198 
  1199 * HOL/split_all_tac is now much faster and fails if there is nothing
  1200 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1201 and the names of the automatically generated variables have changed.
  1202 split_all_tac has moved within claset() from unsafe wrappers to safe
  1203 wrappers, which means that !!-bound variables are split much more
  1204 aggressively, and safe_tac and clarify_tac now split such variables.
  1205 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1206 Note: the same holds for record_split_tac, which does the job of
  1207 split_all_tac for record fields.
  1208 
  1209 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1210 permanently to the default simpset using Addsplits just like
  1211 Addsimps. They can be removed via Delsplits just like
  1212 Delsimps. Lower-case versions are also available.
  1213 
  1214 * HOL/Simplifier: The rule split_if is now part of the default
  1215 simpset. This means that the simplifier will eliminate all occurrences
  1216 of if-then-else in the conclusion of a goal. To prevent this, you can
  1217 either remove split_if completely from the default simpset by
  1218 `Delsplits [split_if]' or remove it in a specific call of the
  1219 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1220 other case splitting rules to/from the default simpset: every datatype
  1221 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1222 t is the name of the datatype).
  1223 
  1224 * Classical reasoner / Simplifier combination: new force_tac (and
  1225 derivatives Force_tac, force) combines rewriting and classical
  1226 reasoning (and whatever other tools) similarly to auto_tac, but is
  1227 aimed to solve the given subgoal completely.
  1228 
  1229 
  1230 *** General ***
  1231 
  1232 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1233 and `goalw': the theory is no longer needed as an explicit argument -
  1234 the current theory context is used; assumptions are no longer returned
  1235 at the ML-level unless one of them starts with ==> or !!; it is
  1236 recommended to convert to these new commands using isatool fixgoal
  1237 (backup your sources first!);
  1238 
  1239 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1240 the current theory context, and 'theory' to lookup stored theories;
  1241 
  1242 * new theory section 'locale' for declaring constants, assumptions and
  1243 definitions that have local scope;
  1244 
  1245 * new theory section 'nonterminals' for purely syntactic types;
  1246 
  1247 * new theory section 'setup' for generic ML setup functions
  1248 (e.g. package initialization);
  1249 
  1250 * the distribution now includes Isabelle icons: see
  1251 lib/logo/isabelle-{small,tiny}.xpm;
  1252 
  1253 * isatool install - install binaries with absolute references to
  1254 ISABELLE_HOME/bin;
  1255 
  1256 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1257 
  1258 * print mode 'emacs' reserved for Isamode;
  1259 
  1260 * support multiple print (ast) translations per constant name;
  1261 
  1262 * theorems involving oracles are now printed with a suffixed [!];
  1263 
  1264 
  1265 *** HOL ***
  1266 
  1267 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1268 
  1269 * HOL/inductive package reorganized and improved: now supports mutual
  1270 definitions such as
  1271 
  1272   inductive EVEN ODD
  1273     intrs
  1274       null "0 : EVEN"
  1275       oddI "n : EVEN ==> Suc n : ODD"
  1276       evenI "n : ODD ==> Suc n : EVEN"
  1277 
  1278 new theorem list "elims" contains an elimination rule for each of the
  1279 recursive sets; inductive definitions now handle disjunctive premises
  1280 correctly (also ZF);
  1281 
  1282 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1283 "mutual_induct" no longer exists - the induction rule is always
  1284 contained in "induct";
  1285 
  1286 
  1287 * HOL/datatype package re-implemented and greatly improved: now
  1288 supports mutually recursive datatypes such as
  1289 
  1290   datatype
  1291     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1292             | SUM ('a aexp) ('a aexp)
  1293             | DIFF ('a aexp) ('a aexp)
  1294             | NUM 'a
  1295   and
  1296     'a bexp = LESS ('a aexp) ('a aexp)
  1297             | AND ('a bexp) ('a bexp)
  1298             | OR ('a bexp) ('a bexp)
  1299 
  1300 as well as indirectly recursive datatypes such as
  1301 
  1302   datatype
  1303     ('a, 'b) term = Var 'a
  1304                   | App 'b ((('a, 'b) term) list)
  1305 
  1306 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1307 induction on mutually / indirectly recursive datatypes.
  1308 
  1309 Primrec equations are now stored in theory and can be accessed via
  1310 <function_name>.simps.
  1311 
  1312 INCOMPATIBILITIES:
  1313 
  1314   - Theories using datatypes must now have theory Datatype as an
  1315     ancestor.
  1316   - The specific <typename>.induct_tac no longer exists - use the
  1317     generic induct_tac instead.
  1318   - natE has been renamed to nat.exhaust - use exhaust_tac
  1319     instead of res_inst_tac ... natE. Note that the variable
  1320     names in nat.exhaust differ from the names in natE, this
  1321     may cause some "fragile" proofs to fail.
  1322   - The theorems split_<typename>_case and split_<typename>_case_asm
  1323     have been renamed to <typename>.split and <typename>.split_asm.
  1324   - Since default sorts of type variables are now handled correctly,
  1325     some datatype definitions may have to be annotated with explicit
  1326     sort constraints.
  1327   - Primrec definitions no longer require function name and type
  1328     of recursive argument.
  1329 
  1330 Consider using isatool fixdatatype to adapt your theories and proof
  1331 scripts to the new package (backup your sources first!).
  1332 
  1333 
  1334 * HOL/record package: considerably improved implementation; now
  1335 includes concrete syntax for record types, terms, updates; theorems
  1336 for surjective pairing and splitting !!-bound record variables; proof
  1337 support is as follows:
  1338 
  1339   1) standard conversions (selectors or updates applied to record
  1340 constructor terms) are part of the standard simpset;
  1341 
  1342   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1343 made part of standard simpset and claset via addIffs;
  1344 
  1345   3) a tactic for record field splitting (record_split_tac) is part of
  1346 the standard claset (addSWrapper);
  1347 
  1348 To get a better idea about these rules you may retrieve them via
  1349 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1350 the name of your record type.
  1351 
  1352 The split tactic 3) conceptually simplifies by the following rule:
  1353 
  1354   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1355 
  1356 Thus any record variable that is bound by meta-all will automatically
  1357 blow up into some record constructor term, consequently the
  1358 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1359 solve record problems automatically.
  1360 
  1361 
  1362 * reorganized the main HOL image: HOL/Integ and String loaded by
  1363 default; theory Main includes everything;
  1364 
  1365 * automatic simplification of integer sums and comparisons, using cancellation;
  1366 
  1367 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1368 
  1369 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1370 
  1371 * many new identities for unions, intersections, set difference, etc.;
  1372 
  1373 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1374 called split_if, split_split, split_sum_case and split_nat_case (to go
  1375 with add/delsplits);
  1376 
  1377 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1378 (?x::unit) = (); this is made part of the default simpset, which COULD
  1379 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1380 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1381 unit_abs_eta_conv is added in order to counter the effect of
  1382 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1383 %u.f();
  1384 
  1385 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1386 makes more sense);
  1387 
  1388 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1389   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1390   disjointness reasoning but breaking a few old proofs.
  1391 
  1392 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1393 to 'converse' from 'inverse' (for compatibility with ZF and some
  1394 literature);
  1395 
  1396 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1397 the well-founded relation;
  1398 
  1399 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1400     Compl A.  The "Compl" syntax remains available as input syntax for this
  1401     release ONLY.
  1402 
  1403 * HOL/Update: new theory of function updates:
  1404     f(a:=b) == %x. if x=a then b else f x
  1405 may also be iterated as in f(a:=b,c:=d,...);
  1406 
  1407 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1408 
  1409 * HOL/List:
  1410   - new function list_update written xs[i:=v] that updates the i-th
  1411     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1412   - new function `upt' written [i..j(] which generates the list
  1413     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1414     bound write [i..j], which is a shorthand for [i..j+1(].
  1415   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1416 
  1417 * HOL/Arith:
  1418   - removed 'pred' (predecessor) function;
  1419   - generalized some theorems about n-1;
  1420   - many new laws about "div" and "mod";
  1421   - new laws about greatest common divisors (see theory ex/Primes);
  1422 
  1423 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1424 instead of "inverse";
  1425 
  1426 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1427   of the multiset ordering;
  1428 
  1429 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1430   (not included by default);
  1431 
  1432 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1433 
  1434 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1435   programs, i.e. different program variables may have different types.
  1436 
  1437 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1438   [previously, this check worked only if the rewrite rule was unconditional]
  1439   Now rew can involve either definitions or equalities (either == or =).
  1440 
  1441 
  1442 *** ZF ***
  1443 
  1444 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1445   only the theorems proved on ZF.ML;
  1446 
  1447 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1448   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1449   disjointness reasoning but breaking a few old proofs.
  1450 
  1451 * ZF/Update: new theory of function updates
  1452     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1453   may also be iterated as in f(a:=b,c:=d,...);
  1454 
  1455 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1456 
  1457 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1458   [previously, this check worked only if the rewrite rule was unconditional]
  1459   Now rew can involve either definitions or equalities (either == or =).
  1460 
  1461 * case_tac provided for compatibility with HOL
  1462     (like the old excluded_middle_tac, but with subgoals swapped)
  1463 
  1464 
  1465 *** Internal programming interfaces ***
  1466 
  1467 * Pure: several new basic modules made available for general use, see
  1468 also src/Pure/README;
  1469 
  1470 * improved the theory data mechanism to support encapsulation (data
  1471 kind name replaced by private Object.kind, acting as authorization
  1472 key); new type-safe user interface via functor TheoryDataFun; generic
  1473 print_data function becomes basically useless;
  1474 
  1475 * removed global_names compatibility flag -- all theory declarations
  1476 are qualified by default;
  1477 
  1478 * module Pure/Syntax now offers quote / antiquote translation
  1479 functions (useful for Hoare logic etc. with implicit dependencies);
  1480 see HOL/ex/Antiquote for an example use;
  1481 
  1482 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1483 cterm -> thm;
  1484 
  1485 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1486 subgoal;
  1487 
  1488 * Display.print_goals function moved to Locale.print_goals;
  1489 
  1490 * standard print function for goals supports current_goals_markers
  1491 variable for marking begin of proof, end of proof, start of goal; the
  1492 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1493 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1494 for example;
  1495 
  1496 
  1497 
  1498 New in Isabelle98 (January 1998)
  1499 --------------------------------
  1500 
  1501 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1502 
  1503 * changed lexical syntax of terms / types: dots made part of long
  1504 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1505 
  1506 * simpset (and claset) reference variable replaced by functions
  1507 simpset / simpset_ref;
  1508 
  1509 * no longer supports theory aliases (via merge) and non-trivial
  1510 implicit merge of thms' signatures;
  1511 
  1512 * most internal names of constants changed due to qualified names;
  1513 
  1514 * changed Pure/Sequence interface (see Pure/seq.ML);
  1515 
  1516 
  1517 *** General Changes ***
  1518 
  1519 * hierachically structured name spaces (for consts, types, axms, thms
  1520 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1521 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1522 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1523 long_names for fully qualified output names; NOTE: ML programs
  1524 (special tactics, packages etc.) referring to internal names may have
  1525 to be adapted to cope with fully qualified names; in case of severe
  1526 backward campatibility problems try setting 'global_names' at compile
  1527 time to have enrything declared within a flat name space; one may also
  1528 fine tune name declarations in theories via the 'global' and 'local'
  1529 section;
  1530 
  1531 * reimplemented the implicit simpset and claset using the new anytype
  1532 data filed in signatures; references simpset:simpset ref etc. are
  1533 replaced by functions simpset:unit->simpset and
  1534 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1535 to patch your ML files accordingly;
  1536 
  1537 * HTML output now includes theory graph data for display with Java
  1538 applet or isatool browser; data generated automatically via isatool
  1539 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1540 
  1541 * defs may now be conditional; improved rewrite_goals_tac to handle
  1542 conditional equations;
  1543 
  1544 * defs now admits additional type arguments, using TYPE('a) syntax;
  1545 
  1546 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1547 creates a new theory node; implicit merge of thms' signatures is
  1548 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1549 transfer:theory->thm->thm in (rare) cases;
  1550 
  1551 * improved handling of draft signatures / theories; draft thms (and
  1552 ctyps, cterms) are automatically promoted to real ones;
  1553 
  1554 * slightly changed interfaces for oracles: admit many per theory, named
  1555 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1556 
  1557 * print_goals: optional output of const types (set show_consts and
  1558 show_types);
  1559 
  1560 * improved output of warnings (###) and errors (***);
  1561 
  1562 * subgoal_tac displays a warning if the new subgoal has type variables;
  1563 
  1564 * removed old README and Makefiles;
  1565 
  1566 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1567 
  1568 * removed obsolete init_pps and init_database;
  1569 
  1570 * deleted the obsolete tactical STATE, which was declared by
  1571     fun STATE tacfun st = tacfun st st;
  1572 
  1573 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1574 (which abbreviates $HOME);
  1575 
  1576 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1577 use isatool fixseq to adapt your ML programs (this works for fully
  1578 qualified references to the Sequence structure only!);
  1579 
  1580 * use_thy no longer requires writable current directory; it always
  1581 reloads .ML *and* .thy file, if either one is out of date;
  1582 
  1583 
  1584 *** Classical Reasoner ***
  1585 
  1586 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1587 tactics that use classical reasoning to simplify a subgoal without
  1588 splitting it into several subgoals;
  1589 
  1590 * Safe_tac: like safe_tac but uses the default claset;
  1591 
  1592 
  1593 *** Simplifier ***
  1594 
  1595 * added simplification meta rules:
  1596     (asm_)(full_)simplify: simpset -> thm -> thm;
  1597 
  1598 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1599 logics (again);
  1600 
  1601 * added prems argument to simplification procedures;
  1602 
  1603 * HOL, FOL, ZF: added infix function `addsplits':
  1604   instead of `<simpset> setloop (split_tac <thms>)'
  1605   you can simply write `<simpset> addsplits <thms>'
  1606 
  1607 
  1608 *** Syntax ***
  1609 
  1610 * TYPE('a) syntax for type reflection terms;
  1611 
  1612 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1613 
  1614 * pretty printer: changed order of mixfix annotation preference (again!);
  1615 
  1616 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1617 
  1618 
  1619 *** HOL ***
  1620 
  1621 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1622   with `addloop' of the simplifier to faciliate case splitting in premises.
  1623 
  1624 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1625 
  1626 * HOL/Auth: new protocol proofs including some for the Internet
  1627   protocol TLS;
  1628 
  1629 * HOL/Map: new theory of `maps' a la VDM;
  1630 
  1631 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1632 cancelling out common nat summands from =, <, <= (in)equalities, or
  1633 differences; simplification procedures nat_cancel_factor for
  1634 cancelling common factor from =, <, <= (in)equalities over natural
  1635 sums; nat_cancel contains both kinds of procedures, it is installed by
  1636 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1637 
  1638 * HOL/simplifier: terms of the form
  1639   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1640   are rewritten to
  1641   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1642   and those of the form
  1643   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1644   are rewritten to
  1645   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1646 
  1647 * HOL/datatype
  1648   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1649 
  1650   P(t_case f1 ... fn x) =
  1651      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1652         ...
  1653        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1654      )
  1655 
  1656   and a theorem `split_t_case_asm' of the form
  1657 
  1658   P(t_case f1 ... fn x) =
  1659     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1660         ...
  1661        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1662      )
  1663   which can be added to a simpset via `addsplits'. The existing theorems
  1664   expand_list_case and expand_option_case have been renamed to
  1665   split_list_case and split_option_case.
  1666 
  1667 * HOL/Arithmetic:
  1668   - `pred n' is automatically converted to `n-1'.
  1669     Users are strongly encouraged not to use `pred' any longer,
  1670     because it will disappear altogether at some point.
  1671   - Users are strongly encouraged to write "0 < n" rather than
  1672     "n ~= 0". Theorems and proof tools have been modified towards this
  1673     `standard'.
  1674 
  1675 * HOL/Lists:
  1676   the function "set_of_list" has been renamed "set" (and its theorems too);
  1677   the function "nth" now takes its arguments in the reverse order and
  1678   has acquired the infix notation "!" as in "xs!n".
  1679 
  1680 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1681 
  1682 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1683   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1684 
  1685 * HOL/record: extensible records with schematic structural subtyping
  1686 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1687 still lacks various theorems and concrete record syntax;
  1688 
  1689 
  1690 *** HOLCF ***
  1691 
  1692 * removed "axioms" and "generated by" sections;
  1693 
  1694 * replaced "ops" section by extended "consts" section, which is capable of
  1695   handling the continuous function space "->" directly;
  1696 
  1697 * domain package:
  1698   . proves theorems immediately and stores them in the theory,
  1699   . creates hierachical name space,
  1700   . now uses normal mixfix annotations (instead of cinfix...),
  1701   . minor changes to some names and values (for consistency),
  1702   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1703   . separator between mutual domain defs: changed "," to "and",
  1704   . improved handling of sort constraints;  now they have to
  1705     appear on the left-hand side of the equations only;
  1706 
  1707 * fixed LAM <x,y,zs>.b syntax;
  1708 
  1709 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1710 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1711 
  1712 
  1713 *** FOL and ZF ***
  1714 
  1715 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1716   with `addloop' of the simplifier to faciliate case splitting in premises.
  1717 
  1718 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1719 in HOL, they strip ALL and --> from proved theorems;
  1720 
  1721 
  1722 
  1723 New in Isabelle94-8 (May 1997)
  1724 ------------------------------
  1725 
  1726 *** General Changes ***
  1727 
  1728 * new utilities to build / run / maintain Isabelle etc. (in parts
  1729 still somewhat experimental); old Makefiles etc. still functional;
  1730 
  1731 * new 'Isabelle System Manual';
  1732 
  1733 * INSTALL text, together with ./configure and ./build scripts;
  1734 
  1735 * reimplemented type inference for greater efficiency, better error
  1736 messages and clean internal interface;
  1737 
  1738 * prlim command for dealing with lots of subgoals (an easier way of
  1739 setting goals_limit);
  1740 
  1741 
  1742 *** Syntax ***
  1743 
  1744 * supports alternative (named) syntax tables (parser and pretty
  1745 printer); internal interface is provided by add_modesyntax(_i);
  1746 
  1747 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1748 be used in conjunction with the Isabelle symbol font; uses the
  1749 "symbols" syntax table;
  1750 
  1751 * added token_translation interface (may translate name tokens in
  1752 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1753 the current print_mode); IMPORTANT: user print translation functions
  1754 are responsible for marking newly introduced bounds
  1755 (Syntax.mark_boundT);
  1756 
  1757 * token translations for modes "xterm" and "xterm_color" that display
  1758 names in bold, underline etc. or colors (which requires a color
  1759 version of xterm);
  1760 
  1761 * infixes may now be declared with names independent of their syntax;
  1762 
  1763 * added typed_print_translation (like print_translation, but may
  1764 access type of constant);
  1765 
  1766 
  1767 *** Classical Reasoner ***
  1768 
  1769 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1770 some limitations.  Blast_tac...
  1771   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1772   + ignores elimination rules that don't have the correct format
  1773         (the conclusion MUST be a formula variable)
  1774   + ignores types, which can make HOL proofs fail
  1775   + rules must not require higher-order unification, e.g. apply_type in ZF
  1776     [message "Function Var's argument not a bound variable" relates to this]
  1777   + its proof strategy is more general but can actually be slower
  1778 
  1779 * substitution with equality assumptions no longer permutes other
  1780 assumptions;
  1781 
  1782 * minor changes in semantics of addafter (now called addaltern); renamed
  1783 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1784 (and access functions for it);
  1785 
  1786 * improved combination of classical reasoner and simplifier:
  1787   + functions for handling clasimpsets
  1788   + improvement of addss: now the simplifier is called _after_ the
  1789     safe steps.
  1790   + safe variant of addss called addSss: uses safe simplifications
  1791     _during_ the safe steps. It is more complete as it allows multiple
  1792     instantiations of unknowns (e.g. with slow_tac).
  1793 
  1794 *** Simplifier ***
  1795 
  1796 * added interface for simplification procedures (functions that
  1797 produce *proven* rewrite rules on the fly, depending on current
  1798 redex);
  1799 
  1800 * ordering on terms as parameter (used for ordered rewriting);
  1801 
  1802 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1803 
  1804 * the solver is now split into a safe and an unsafe part.
  1805 This should be invisible for the normal user, except that the
  1806 functions setsolver and addsolver have been renamed to setSolver and
  1807 addSolver; added safe_asm_full_simp_tac;
  1808 
  1809 
  1810 *** HOL ***
  1811 
  1812 * a generic induction tactic `induct_tac' which works for all datatypes and
  1813 also for type `nat';
  1814 
  1815 * a generic case distinction tactic `exhaust_tac' which works for all
  1816 datatypes and also for type `nat';
  1817 
  1818 * each datatype comes with a function `size';
  1819 
  1820 * patterns in case expressions allow tuple patterns as arguments to
  1821 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1822 
  1823 * primrec now also works with type nat;
  1824 
  1825 * recdef: a new declaration form, allows general recursive functions to be
  1826 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1827 
  1828 * the constant for negation has been renamed from "not" to "Not" to
  1829 harmonize with FOL, ZF, LK, etc.;
  1830 
  1831 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1832 infinite lists;
  1833 
  1834 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1835 
  1836 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1837 problems in commutative rings, using axiomatic type classes for + and *;
  1838 
  1839 * more examples in HOL/MiniML and HOL/Auth;
  1840 
  1841 * more default rewrite rules for quantifiers, union/intersection;
  1842 
  1843 * a new constant `arbitrary == @x.False';
  1844 
  1845 * HOLCF/IOA replaces old HOL/IOA;
  1846 
  1847 * HOLCF changes: derived all rules and arities
  1848   + axiomatic type classes instead of classes
  1849   + typedef instead of faking type definitions
  1850   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1851   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1852   + eliminated the types void, one, tr
  1853   + use unit lift and bool lift (with translations) instead of one and tr
  1854   + eliminated blift from Lift3.thy (use Def instead of blift)
  1855   all eliminated rules are derived as theorems --> no visible changes ;
  1856 
  1857 
  1858 *** ZF ***
  1859 
  1860 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1861 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1862 as ZF_cs addSIs [equalityI];
  1863 
  1864 
  1865 
  1866 New in Isabelle94-7 (November 96)
  1867 ---------------------------------
  1868 
  1869 * allowing negative levels (as offsets) in prlev and choplev;
  1870 
  1871 * super-linear speedup for large simplifications;
  1872 
  1873 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1874 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1875 FAIL); can suppress it using the command Delsimps (ex_simps @
  1876 all_simps); De Morgan laws are also now included, by default;
  1877 
  1878 * improved printing of ==>  :  ~:
  1879 
  1880 * new object-logic "Sequents" adds linear logic, while replacing LK
  1881 and Modal (thanks to Sara Kalvala);
  1882 
  1883 * HOL/Auth: correctness proofs for authentication protocols;
  1884 
  1885 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1886 examples on HOL/Auth);
  1887 
  1888 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1889 the rewriter and classical reasoner simultaneously;
  1890 
  1891 * function uresult no longer returns theorems in "standard" format;
  1892 regain previous version by: val uresult = standard o uresult;
  1893 
  1894 
  1895 
  1896 New in Isabelle94-6
  1897 -------------------
  1898 
  1899 * oracles -- these establish an interface between Isabelle and trusted
  1900 external reasoners, which may deliver results as theorems;
  1901 
  1902 * proof objects (in particular record all uses of oracles);
  1903 
  1904 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1905 
  1906 * "constdefs" section in theory files;
  1907 
  1908 * "primrec" section (HOL) no longer requires names;
  1909 
  1910 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1911 
  1912 
  1913 
  1914 New in Isabelle94-5
  1915 -------------------
  1916 
  1917 * reduced space requirements;
  1918 
  1919 * automatic HTML generation from theories;
  1920 
  1921 * theory files no longer require "..." (quotes) around most types;
  1922 
  1923 * new examples, including two proofs of the Church-Rosser theorem;
  1924 
  1925 * non-curried (1994) version of HOL is no longer distributed;
  1926 
  1927 
  1928 
  1929 New in Isabelle94-4
  1930 -------------------
  1931 
  1932 * greatly reduced space requirements;
  1933 
  1934 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1935 
  1936 * searchable theorem database (see the section "Retrieving theorems" on
  1937 page 8 of the Reference Manual);
  1938 
  1939 * new examples, including Grabczewski's monumental case study of the
  1940 Axiom of Choice;
  1941 
  1942 * The previous version of HOL renamed to Old_HOL;
  1943 
  1944 * The new version of HOL (previously called CHOL) uses a curried syntax
  1945 for functions.  Application looks like f a b instead of f(a,b);
  1946 
  1947 * Mutually recursive inductive definitions finally work in HOL;
  1948 
  1949 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1950 translates to the operator "split";
  1951 
  1952 
  1953 
  1954 New in Isabelle94-3
  1955 -------------------
  1956 
  1957 * new infix operator, addss, allowing the classical reasoner to
  1958 perform simplification at each step of its search.  Example:
  1959         fast_tac (cs addss ss)
  1960 
  1961 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1962 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1963 look like (a,b) instead of <a,b>;
  1964 
  1965 * PLEASE NOTE: CHOL will eventually replace HOL!
  1966 
  1967 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1968 It translates to the operator "split".  A new theory of integers is available;
  1969 
  1970 * In ZF, integer numerals now denote two's-complement binary integers.
  1971 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1972 
  1973 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1974 of the Axiom of Choice;
  1975 
  1976 
  1977 
  1978 New in Isabelle94-2
  1979 -------------------
  1980 
  1981 * Significantly faster resolution;
  1982 
  1983 * the different sections in a .thy file can now be mixed and repeated
  1984 freely;
  1985 
  1986 * Database of theorems for FOL, HOL and ZF.  New
  1987 commands including qed, qed_goal and bind_thm store theorems in the database.
  1988 
  1989 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1990 a given theory (thms_of), or find out what theory a theorem was proved in
  1991 (theory_of_thm);
  1992 
  1993 * Bugs fixed in the inductive definition and datatype packages;
  1994 
  1995 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1996 and HOL_dup_cs obsolete;
  1997 
  1998 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1999 have been removed;
  2000 
  2001 * Simpler definition of function space in ZF;
  2002 
  2003 * new results about cardinal and ordinal arithmetic in ZF;
  2004 
  2005 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2006 types;
  2007 
  2008 
  2009 $Id$