NEWS
author wenzelm
Sat Nov 03 01:33:33 2001 +0100 (2001-11-03)
changeset 12022 9c3377b133c0
parent 11995 4a622f5fb164
child 12034 4471077c4d4f
permissions -rw-r--r--
HOLCF: proper rep_datatype lift (see theory Lift); use plain induct_tac
instead of lift.induct_tac, use UU instead of Undef in cases;
     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 lift.induct_tac, use UU instead of Undef in all cases;
   174 
   175 
   176 *** ZF ***
   177 
   178 * ZF: the integer library now covers quotients and remainders, with
   179 many laws relating division to addition, multiplication, etc.;
   180 
   181 
   182 *** General ***
   183 
   184 * kernel: meta-level proof terms (by Stefan Berghofer), see also ref
   185 manual;
   186 
   187 * Pure/axclass: removed obsolete ML interface goal_subclass/goal_arity;
   188 
   189 * classical: renamed addaltern to addafter, addSaltern to addSafter;
   190 
   191 * clasimp: ``iff'' declarations now handle conditional rules as well;
   192 
   193 * syntax: new token syntax "num" for plain numerals (without "#" of
   194 "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now separate
   195 tokens, so expressions involving minus need to be spaced properly;
   196 
   197 * syntax: support non-oriented infixes;
   198 
   199 * syntax: print modes "type_brackets" and "no_type_brackets" control
   200 output of nested => (types); the default behavior is "type_brackets";
   201 
   202 * syntax: builtin parse translation for "_constify" turns valued
   203 tokens into AST constants;
   204 
   205 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   206 
   207 * system: Proof General keywords specification is now part of the
   208 Isabelle distribution (see etc/isar-keywords.el);
   209 
   210 * system: smart selection of Isabelle process versus Isabelle
   211 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   212 run both "isabelle" and "Isabelle" even if file names are badly
   213 damaged (executable inspects the case of the first letter of its own
   214 name); added separate "isabelle-process" and "isabelle-interface";
   215 
   216 
   217 
   218 New in Isabelle99-2 (February 2001)
   219 -----------------------------------
   220 
   221 *** Overview of INCOMPATIBILITIES ***
   222 
   223 * HOL: please note that theories in the Library and elsewhere often use the
   224 new-style (Isar) format; to refer to their theorems in an ML script you must
   225 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   226 
   227 * HOL: inductive package no longer splits induction rule aggressively,
   228 but only as far as specified by the introductions given; the old
   229 format may be recovered via ML function complete_split_rule or attribute
   230 'split_rule (complete)';
   231 
   232 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   233 gfp_Tarski to gfp_unfold;
   234 
   235 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   236 
   237 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   238 relation); infix "^^" has been renamed "``"; infix "``" has been
   239 renamed "`"; "univalent" has been renamed "single_valued";
   240 
   241 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   242 operation;
   243 
   244 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   245 
   246 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   247 
   248 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   249 consequence, it is no longer monotonic wrt. the local goal context
   250 (which is now passed through the inductive cases);
   251 
   252 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   253 \<gg> to \<ggreater>;
   254 
   255 
   256 *** Document preparation ***
   257 
   258 * \isabellestyle{NAME} selects version of Isabelle output (currently
   259 available: are "it" for near math-mode best-style output, "sl" for
   260 slanted text style, and "tt" for plain type-writer; if no
   261 \isabellestyle command is given, output is according to slanted
   262 type-writer);
   263 
   264 * support sub/super scripts (for single symbols only), input syntax is
   265 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   266 
   267 * some more standard symbols; see Appendix A of the system manual for
   268 the complete list of symbols defined in isabellesym.sty;
   269 
   270 * improved isabelle style files; more abstract symbol implementation
   271 (should now use \isamath{...} and \isatext{...} in custom symbol
   272 definitions);
   273 
   274 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   275 state; Note that presentation of goal states does not conform to
   276 actual human-readable proof documents.  Please do not include goal
   277 states into document output unless you really know what you are doing!
   278 
   279 * proper indentation of antiquoted output with proportional LaTeX
   280 fonts;
   281 
   282 * no_document ML operator temporarily disables LaTeX document
   283 generation;
   284 
   285 * isatool unsymbolize tunes sources for plain ASCII communication;
   286 
   287 
   288 *** Isar ***
   289 
   290 * Pure: Isar now suffers initial goal statements to contain unbound
   291 schematic variables (this does not conform to actual readable proof
   292 documents, due to unpredictable outcome and non-compositional proof
   293 checking); users who know what they are doing may use schematic goals
   294 for Prolog-style synthesis of proven results;
   295 
   296 * Pure: assumption method (an implicit finishing) now handles actual
   297 rules as well;
   298 
   299 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   300 initial goal, declare "that" only as Pure intro (only for single
   301 steps); the "that" rule assumption may now be involved in implicit
   302 finishing, thus ".." becomes a feasible for trivial obtains;
   303 
   304 * Pure: default proof step now includes 'intro_classes'; thus trivial
   305 instance proofs may be performed by "..";
   306 
   307 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   308 statements as well;
   309 
   310 * Pure: more robust selection of calculational rules;
   311 
   312 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   313 rule (as well as the assumption rule);
   314 
   315 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   316 lemmas, using the graph browser tool;
   317 
   318 * Pure: predict failure of "show" in interactive mode;
   319 
   320 * Pure: 'thms_containing' now takes actual terms as arguments;
   321 
   322 * HOL: improved method 'induct' --- now handles non-atomic goals
   323 (potential INCOMPATIBILITY); tuned error handling;
   324 
   325 * HOL: cases and induct rules now provide explicit hints about the
   326 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   327 any remaining facts are inserted into the goal verbatim;
   328 
   329 * HOL: local contexts (aka cases) may now contain term bindings as
   330 well; the 'cases' and 'induct' methods new provide a ?case binding for
   331 the result to be shown in each case;
   332 
   333 * HOL: added 'recdef_tc' command;
   334 
   335 * isatool convert assists in eliminating legacy ML scripts;
   336 
   337 
   338 *** HOL ***
   339 
   340 * HOL/Library: a collection of generic theories to be used together
   341 with main HOL; the theory loader path already includes this directory
   342 by default; the following existing theories have been moved here:
   343 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   344 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   345 
   346 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   347 modelling and verification task performed in Isabelle/HOL +
   348 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   349 
   350 * HOL/Algebra: special summation operator SUM no longer exists, it has
   351 been replaced by setsum; infix 'assoc' now has priority 50 (like
   352 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   353 'domain', this makes the theory consistent with mathematical
   354 literature;
   355 
   356 * HOL basics: added overloaded operations "inverse" and "divide"
   357 (infix "/"), syntax for generic "abs" operation, generic summation
   358 operator \<Sum>;
   359 
   360 * HOL/typedef: simplified package, provide more useful rules (see also
   361 HOL/subset.thy);
   362 
   363 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   364 now expressed as a proper nested rule (old-style tactic scripts may
   365 require atomize_strip_tac to cope with non-atomic premises);
   366 
   367 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   368 to "split_conv" (old name still available for compatibility);
   369 
   370 * HOL: improved concrete syntax for strings (e.g. allows translation
   371 rules with string literals);
   372 
   373 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   374 and Fleuriot's mechanization of analysis;
   375 
   376 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   377 
   378 
   379 *** CTT ***
   380 
   381 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   382 "lam" is displayed as TWO lambda-symbols
   383 
   384 * CTT: theory Main now available, containing everything (that is, Bool
   385 and Arith);
   386 
   387 
   388 *** General ***
   389 
   390 * Pure: the Simplifier has been implemented properly as a derived rule
   391 outside of the actual kernel (at last!); the overall performance
   392 penalty in practical applications is about 50%, while reliability of
   393 the Isabelle inference kernel has been greatly improved;
   394 
   395 * print modes "brackets" and "no_brackets" control output of nested =>
   396 (types) and ==> (props); the default behaviour is "brackets";
   397 
   398 * Provers: fast_tac (and friends) now handle actual object-logic rules
   399 as assumptions as well;
   400 
   401 * system: support Poly/ML 4.0;
   402 
   403 * system: isatool install handles KDE version 1 or 2;
   404 
   405 
   406 
   407 New in Isabelle99-1 (October 2000)
   408 ----------------------------------
   409 
   410 *** Overview of INCOMPATIBILITIES ***
   411 
   412 * HOL: simplification of natural numbers is much changed; to partly
   413 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   414 issue the following ML commands:
   415 
   416   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   417   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   418 
   419 * HOL: simplification no longer dives into case-expressions; this is
   420 controlled by "t.weak_case_cong" for each datatype t;
   421 
   422 * HOL: nat_less_induct renamed to less_induct;
   423 
   424 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   425 fixsome to patch .thy and .ML sources automatically;
   426 
   427   select_equality  -> some_equality
   428   select_eq_Ex     -> some_eq_ex
   429   selectI2EX       -> someI2_ex
   430   selectI2         -> someI2
   431   selectI          -> someI
   432   select1_equality -> some1_equality
   433   Eps_sym_eq       -> some_sym_eq_trivial
   434   Eps_eq           -> some_eq_trivial
   435 
   436 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   437 
   438 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   439 instead);
   440 
   441 * HOL: the recursion equations generated by 'recdef' are now called
   442 f.simps instead of f.rules;
   443 
   444 * HOL: qed_spec_mp now also handles bounded ALL as well;
   445 
   446 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   447 sometimes be needed;
   448 
   449 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   450 
   451 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   452 
   453 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   454 product is now "<*>" instead of "Times"; the lexicographic product is
   455 now "<*lex*>" instead of "**";
   456 
   457 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   458 of main HOL, but was unused); better use HOL's datatype package;
   459 
   460 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   461 the old syntax may be recovered as follows:
   462 
   463   syntax (symbols)
   464     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   465       (infixl "\\<oplus>" 100)
   466 
   467 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   468 
   469 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   470 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   471 internally;
   472 
   473 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   474 changed from A/r to A//r;
   475 
   476 * ZF: new treatment of arithmetic (nat & int) may break some old
   477 proofs;
   478 
   479 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   480 rulify -> rule_format, elimify -> elim_format, ...);
   481 
   482 * Isar/Provers: intro/elim/dest attributes changed; renamed
   483 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   484 should have to change intro!! to intro? only); replaced "delrule" by
   485 "rule del";
   486 
   487 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   488 
   489 * Provers: strengthened force_tac by using new first_best_tac;
   490 
   491 * LaTeX document preparation: several changes of isabelle.sty (see
   492 lib/texinputs);
   493 
   494 
   495 *** Document preparation ***
   496 
   497 * formal comments (text blocks etc.) in new-style theories may now
   498 contain antiquotations of thm/prop/term/typ/text to be presented
   499 according to latex print mode; concrete syntax is like this:
   500 @{term[show_types] "f(x) = a + x"};
   501 
   502 * isatool mkdir provides easy setup of Isabelle session directories,
   503 including proper document sources;
   504 
   505 * generated LaTeX sources are now deleted after successful run
   506 (isatool document -c); may retain a copy somewhere else via -D option
   507 of isatool usedir;
   508 
   509 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   510 style files, achieving self-contained LaTeX sources and simplifying
   511 LaTeX debugging;
   512 
   513 * old-style theories now produce (crude) LaTeX output as well;
   514 
   515 * browser info session directories are now self-contained (may be put
   516 on WWW server seperately); improved graphs of nested sessions; removed
   517 graph for 'all sessions';
   518 
   519 * several improvements in isabelle style files; \isabellestyle{it}
   520 produces fake math mode output; \isamarkupheader is now \section by
   521 default; see lib/texinputs/isabelle.sty etc.;
   522 
   523 
   524 *** Isar ***
   525 
   526 * Isar/Pure: local results and corresponding term bindings are now
   527 subject to Hindley-Milner polymorphism (similar to ML); this
   528 accommodates incremental type-inference very nicely;
   529 
   530 * Isar/Pure: new derived language element 'obtain' supports
   531 generalized existence reasoning;
   532 
   533 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   534 support accumulation of results, without applying any rules yet;
   535 useful to collect intermediate results without explicit name
   536 references, and for use with transitivity rules with more than 2
   537 premises;
   538 
   539 * Isar/Pure: scalable support for case-analysis type proofs: new
   540 'case' language element refers to local contexts symbolically, as
   541 produced by certain proof methods; internally, case names are attached
   542 to theorems as "tags";
   543 
   544 * Isar/Pure: theory command 'hide' removes declarations from
   545 class/type/const name spaces;
   546 
   547 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   548 indicate potential overloading;
   549 
   550 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   551 
   552 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   553 "{a,b,c}" instead of {a,b,c};
   554 
   555 * Isar/Pure now provides its own version of intro/elim/dest
   556 attributes; useful for building new logics, but beware of confusion
   557 with the version in Provers/classical;
   558 
   559 * Isar/Pure: the local context of (non-atomic) goals is provided via
   560 case name 'antecedent';
   561 
   562 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   563 to the current context is now done automatically);
   564 
   565 * Isar/Pure: theory command 'method_setup' provides a simple interface
   566 for definining proof methods in ML;
   567 
   568 * Isar/Provers: intro/elim/dest attributes changed; renamed
   569 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   570 most cases, one should have to change intro!! to intro? only);
   571 replaced "delrule" by "rule del";
   572 
   573 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   574 'symmetric' attribute (the latter supercedes [RS sym]);
   575 
   576 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   577 method modifier); 'simp' method: 'only:' modifier removes loopers as
   578 well (including splits);
   579 
   580 * Isar/Provers: Simplifier and Classical methods now support all kind
   581 of modifiers used in the past, including 'cong', 'iff', etc.
   582 
   583 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   584 of Simplifier and Classical reasoner);
   585 
   586 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   587 now support named cases; major packages (inductive, datatype, primrec,
   588 recdef) support case names and properly name parameters;
   589 
   590 * Isar/HOL: new transitivity rules for substitution in inequalities --
   591 monotonicity conditions are extracted to be proven at end of
   592 calculations;
   593 
   594 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   595 method anyway;
   596 
   597 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   598 split_if split_if_asm; datatype package provides theorems foo.splits =
   599 foo.split foo.split_asm for each datatype;
   600 
   601 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   602 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   603 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   604 use "(cases (simplified))" method in proper proof texts);
   605 
   606 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   607 
   608 * Isar: names of theorems etc. may be natural numbers as well;
   609 
   610 * Isar: 'pr' command: optional arguments for goals_limit and
   611 ProofContext.prems_limit; no longer prints theory contexts, but only
   612 proof states;
   613 
   614 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   615 additional print modes to be specified; e.g. "pr(latex)" will print
   616 proof state according to the Isabelle LaTeX style;
   617 
   618 * Isar: improved support for emulating tactic scripts, including proof
   619 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   620 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   621 (for HOL datatypes);
   622 
   623 * Isar: simplified (more robust) goal selection of proof methods: 1st
   624 goal, all goals, or explicit goal specifier (tactic emulation); thus
   625 'proof method scripts' have to be in depth-first order;
   626 
   627 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   628 
   629 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   630 should instead use individual commands for printing items
   631 (print_commands, print_methods etc.);
   632 
   633 * Isar: added 'nothing' --- the empty list of theorems;
   634 
   635 
   636 *** HOL ***
   637 
   638 * HOL/MicroJava: formalization of a fragment of Java, together with a
   639 corresponding virtual machine and a specification of its bytecode
   640 verifier and a lightweight bytecode verifier, including proofs of
   641 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   642 Cornelia Pusch (see also the homepage of project Bali at
   643 http://isabelle.in.tum.de/Bali/);
   644 
   645 * HOL/Algebra: new theory of rings and univariate polynomials, by
   646 Clemens Ballarin;
   647 
   648 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   649 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   650 Rasmussen;
   651 
   652 * HOL/Lattice: fundamental concepts of lattice theory and order
   653 structures, including duals, properties of bounds versus algebraic
   654 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   655 Theorem for complete lattices etc.; may also serve as a demonstration
   656 for abstract algebraic reasoning using axiomatic type classes, and
   657 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   658 
   659 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   660 von Oheimb;
   661 
   662 * HOL/IMPP: extension of IMP with local variables and mutually
   663 recursive procedures, by David von Oheimb;
   664 
   665 * HOL/Lambda: converted into new-style theory and document;
   666 
   667 * HOL/ex/Multiquote: example of multiple nested quotations and
   668 anti-quotations -- basically a generalized version of de-Bruijn
   669 representation; very useful in avoiding lifting of operations;
   670 
   671 * HOL/record: added general record equality rule to simpset; fixed
   672 select-update simplification procedure to handle extended records as
   673 well; admit "r" as field name;
   674 
   675 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   676 other numeric types and also as the identity of groups, rings, etc.;
   677 
   678 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   679 Types nat and int belong to this axclass;
   680 
   681 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   682    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   683    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   684   two terms #m*u and #n*u are replaced by #(m+n)*u
   685     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   686   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   687     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   688 
   689 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   690 powerful prover for predicate logic but knows nothing of clasets; see
   691 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   692 
   693 * HOL: new version of "case_tac" subsumes both boolean case split and
   694 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   695 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   696 
   697 * HOL: simplification no longer dives into case-expressions: only the
   698 selector expression is simplified, but not the remaining arms; to
   699 enable full simplification of case-expressions for datatype t, you may
   700 remove t.weak_case_cong from the simpset, either globally (Delcongs
   701 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   702 
   703 * HOL/recdef: the recursion equations generated by 'recdef' for
   704 function 'f' are now called f.simps instead of f.rules; if all
   705 termination conditions are proved automatically, these simplification
   706 rules are added to the simpset, as in primrec; rules may be named
   707 individually as well, resulting in a separate list of theorems for
   708 each equation;
   709 
   710 * HOL/While is a new theory that provides a while-combinator. It
   711 permits the definition of tail-recursive functions without the
   712 provision of a termination measure. The latter is necessary once the
   713 invariant proof rule for while is applied.
   714 
   715 * HOL: new (overloaded) notation for the set of elements below/above
   716 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   717 
   718 * HOL: theorems impI, allI, ballI bound as "strip";
   719 
   720 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   721 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   722 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   723 
   724 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   725 
   726 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   727 main HOL, but was unused);
   728 
   729 * HOL: fewer consts declared as global (e.g. have to refer to
   730 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   731 
   732 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   733 in case of overlap with user translations (e.g. judgements over
   734 tuples); (note that the underlying logical represenation is still
   735 bogus);
   736 
   737 
   738 *** ZF ***
   739 
   740 * ZF: simplification automatically cancels common terms in arithmetic
   741 expressions over nat and int;
   742 
   743 * ZF: new treatment of nat to minimize type-checking: all operators
   744 coerce their operands to a natural number using the function natify,
   745 making the algebraic laws unconditional;
   746 
   747 * ZF: as above, for int: operators coerce their operands to an integer
   748 using the function intify;
   749 
   750 * ZF: the integer library now contains many of the usual laws for the
   751 orderings, including $<=, and monotonicity laws for $+ and $*;
   752 
   753 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   754 simplification;
   755 
   756 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   757 to the simplifier and classical reasoner simultaneously;
   758 
   759 
   760 *** General ***
   761 
   762 * Provers: blast_tac now handles actual object-logic rules as
   763 assumptions; note that auto_tac uses blast_tac internally as well;
   764 
   765 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   766 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   767 
   768 * Provers: delrules now handles destruct rules as well (no longer need
   769 explicit make_elim);
   770 
   771 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   772   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   773 use instead the strong form,
   774   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   775 in HOL, FOL and ZF the function cla_make_elim will create such rules
   776 from destruct-rules;
   777 
   778 * Provers: Simplifier.easy_setup provides a fast path to basic
   779 Simplifier setup for new object-logics;
   780 
   781 * Pure: AST translation rules no longer require constant head on LHS;
   782 
   783 * Pure: improved name spaces: ambiguous output is qualified; support
   784 for hiding of names;
   785 
   786 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   787 XSYMBOL_HOME; no longer need to do manual configuration in most
   788 situations;
   789 
   790 * system: compression of ML heaps images may now be controlled via -c
   791 option of isabelle and isatool usedir (currently only observed by
   792 Poly/ML);
   793 
   794 * system: isatool installfonts may handle X-Symbol fonts as well (very
   795 useful for remote X11);
   796 
   797 * system: provide TAGS file for Isabelle sources;
   798 
   799 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   800 order;
   801 
   802 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   803 timing flag supersedes proof_timing and Toplevel.trace;
   804 
   805 * ML: new combinators |>> and |>>> for incremental transformations
   806 with secondary results (e.g. certain theory extensions):
   807 
   808 * ML: PureThy.add_defs gets additional argument to indicate potential
   809 overloading (usually false);
   810 
   811 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   812 results;
   813 
   814 
   815 
   816 New in Isabelle99 (October 1999)
   817 --------------------------------
   818 
   819 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   820 
   821 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   822 are no longer simplified.  (This allows the simplifier to unfold recursive
   823 functional programs.)  To restore the old behaviour, declare
   824 
   825     Delcongs [if_weak_cong];
   826 
   827 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   828 complement;
   829 
   830 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   831 
   832 * HOL/datatype: mutual_induct_tac no longer exists --
   833   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   834 
   835 * HOL/typedef: fixed type inference for representing set; type
   836 arguments now have to occur explicitly on the rhs as type constraints;
   837 
   838 * ZF: The con_defs part of an inductive definition may no longer refer
   839 to constants declared in the same theory;
   840 
   841 * HOL, ZF: the function mk_cases, generated by the inductive
   842 definition package, has lost an argument.  To simplify its result, it
   843 uses the default simpset instead of a supplied list of theorems.
   844 
   845 * HOL/List: the constructors of type list are now Nil and Cons;
   846 
   847 * Simplifier: the type of the infix ML functions
   848         setSSolver addSSolver setSolver addSolver
   849 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   850 for packaging solvers. A solver is created via
   851         mk_solver: string -> (thm list -> int -> tactic) -> solver
   852 where the string argument is only a comment.
   853 
   854 
   855 *** Proof tools ***
   856 
   857 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   858 decision procedure for linear arithmetic. Currently it is used for
   859 types `nat', `int', and `real' in HOL (see below); it can, should and
   860 will be instantiated for other types and logics as well.
   861 
   862 * The simplifier now accepts rewrite rules with flexible heads, eg
   863      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   864   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   865   matching.
   866 
   867 
   868 *** General ***
   869 
   870 * New Isabelle/Isar subsystem provides an alternative to traditional
   871 tactical theorem proving; together with the ProofGeneral/isar user
   872 interface it offers an interactive environment for developing human
   873 readable proof documents (Isar == Intelligible semi-automated
   874 reasoning); for further information see isatool doc isar-ref,
   875 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   876 
   877 * improved and simplified presentation of theories: better HTML markup
   878 (including colors), graph views in several sizes; isatool usedir now
   879 provides a proper interface for user theories (via -P option); actual
   880 document preparation based on (PDF)LaTeX is available as well (for
   881 new-style theories only); see isatool doc system for more information;
   882 
   883 * native support for Proof General, both for classic Isabelle and
   884 Isabelle/Isar;
   885 
   886 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   887 using the graph browser tool;
   888 
   889 * Isabelle manuals now also available as PDF;
   890 
   891 * theory loader rewritten from scratch (may not be fully
   892 bug-compatible); old loadpath variable has been replaced by show_path,
   893 add_path, del_path, reset_path functions; new operations such as
   894 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   895 isatool doc ref);
   896 
   897 * improved isatool install: option -k creates KDE application icon,
   898 option -p DIR installs standalone binaries;
   899 
   900 * added ML_PLATFORM setting (useful for cross-platform installations);
   901 more robust handling of platform specific ML images for SML/NJ;
   902 
   903 * the settings environment is now statically scoped, i.e. it is never
   904 created again in sub-processes invoked from isabelle, isatool, or
   905 Isabelle;
   906 
   907 * path element specification '~~' refers to '$ISABELLE_HOME';
   908 
   909 * in locales, the "assumes" and "defines" parts may be omitted if
   910 empty;
   911 
   912 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   913 long arrows);
   914 
   915 * new print_mode "HTML";
   916 
   917 * new flag show_tags controls display of tags of theorems (which are
   918 basically just comments that may be attached by some tools);
   919 
   920 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   921 mode and goal output format:
   922 
   923 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   924 244c244
   925 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   926 ---
   927 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   928 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   929 181c181
   930 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   931 ---
   932 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   933 
   934 * function bind_thms stores lists of theorems (cf. bind_thm);
   935 
   936 * new shorthand tactics ftac, eatac, datac, fatac;
   937 
   938 * qed (and friends) now accept "" as result name; in that case the
   939 theorem is not stored, but proper checks and presentation of the
   940 result still apply;
   941 
   942 * theorem database now also indexes constants "Trueprop", "all",
   943 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   944 
   945 
   946 *** HOL ***
   947 
   948 ** HOL arithmetic **
   949 
   950 * There are now decision procedures for linear arithmetic over nat and
   951 int:
   952 
   953 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   954 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   955 are treated as atomic; subformulae not involving type `nat' or `int'
   956 are ignored; quantified subformulae are ignored unless they are
   957 positive universal or negative existential. The tactic has to be
   958 invoked by hand and can be a little bit slow. In particular, the
   959 running time is exponential in the number of occurrences of `min' and
   960 `max', and `-' on `nat'.
   961 
   962 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   963 (negated) (in)equalities among the premises and the conclusion into
   964 account (i.e. no compound formulae) and does not know about `min' and
   965 `max', and `-' on `nat'. It is fast and is used automatically by the
   966 simplifier.
   967 
   968 NB: At the moment, these decision procedures do not cope with mixed
   969 nat/int formulae where the two parts interact, such as `m < n ==>
   970 int(m) < int(n)'.
   971 
   972 * HOL/Numeral provides a generic theory of numerals (encoded
   973 efficiently as bit strings); setup for types nat/int/real is in place;
   974 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   975 int, existing theories and proof scripts may require a few additional
   976 type constraints;
   977 
   978 * integer division and remainder can now be performed on constant
   979 arguments;
   980 
   981 * many properties of integer multiplication, division and remainder
   982 are now available;
   983 
   984 * An interface to the Stanford Validity Checker (SVC) is available through the
   985 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   986 are proved automatically.  SVC must be installed separately, and its results
   987 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   988 invocation of the underlying oracle).  For SVC see
   989   http://verify.stanford.edu/SVC
   990 
   991 * IsaMakefile: the HOL-Real target now builds an actual image;
   992 
   993 
   994 ** HOL misc **
   995 
   996 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   997 (in Isabelle/Isar) -- by Gertrud Bauer;
   998 
   999 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1000 analysis for assembly languages with subtypes;
  1001 
  1002 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1003 -- avoids syntactic ambiguities and treats state, transition, and
  1004 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1005 changed syntax and (many) tactics;
  1006 
  1007 * HOL/inductive: Now also handles more general introduction rules such
  1008   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1009   theorems are now maintained within the theory (maintained via the
  1010   "mono" attribute);
  1011 
  1012 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1013   (using function types) such as
  1014 
  1015   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1016 
  1017 * HOL/record: record_simproc (part of the default simpset) takes care
  1018 of selectors applied to updated records; record_split_tac is no longer
  1019 part of the default claset; update_defs may now be removed from the
  1020 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1021 
  1022   claset_ref () := claset() addSWrapper record_split_wrapper;
  1023   Delsimprocs [record_simproc]
  1024 
  1025 * HOL/typedef: fixed type inference for representing set; type
  1026 arguments now have to occur explicitly on the rhs as type constraints;
  1027 
  1028 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1029 names rather than an ML expression;
  1030 
  1031 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1032 supplied later.  Program schemes can be defined, such as
  1033     "While B C s = (if B s then While B C (C s) else s)"
  1034 where the well-founded relation can be chosen after B and C have been given.
  1035 
  1036 * HOL/List: the constructors of type list are now Nil and Cons;
  1037 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1038 course, ML tools referring to List.list.op # etc. have to be adapted;
  1039 
  1040 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1041 disabled by default; run isabelle with option -m HOL to get back to
  1042 the original Gordon/HOL-style output;
  1043 
  1044 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1045 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1046 
  1047 * HOL basic syntax simplified (more orthogonal): all variants of
  1048 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1049 Eps operator is provided as well: "SOME x. P[x]";
  1050 
  1051 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1052 
  1053 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1054 thus available for user theories;
  1055 
  1056 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1057 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1058 time;
  1059 
  1060 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1061 several times and then mp;
  1062 
  1063 
  1064 *** LK ***
  1065 
  1066 * the notation <<...>> is now available as a notation for sequences of
  1067 formulas;
  1068 
  1069 * the simplifier is now installed
  1070 
  1071 * the axiom system has been generalized (thanks to Soren Heilmann)
  1072 
  1073 * the classical reasoner now has a default rule database
  1074 
  1075 
  1076 *** ZF ***
  1077 
  1078 * new primrec section allows primitive recursive functions to be given
  1079 directly (as in HOL) over datatypes and the natural numbers;
  1080 
  1081 * new tactics induct_tac and exhaust_tac for induction (or case
  1082 analysis) over datatypes and the natural numbers;
  1083 
  1084 * the datatype declaration of type T now defines the recursor T_rec;
  1085 
  1086 * simplification automatically does freeness reasoning for datatype
  1087 constructors;
  1088 
  1089 * automatic type-inference, with AddTCs command to insert new
  1090 type-checking rules;
  1091 
  1092 * datatype introduction rules are now added as Safe Introduction rules
  1093 to the claset;
  1094 
  1095 * the syntax "if P then x else y" is now available in addition to
  1096 if(P,x,y);
  1097 
  1098 
  1099 *** Internal programming interfaces ***
  1100 
  1101 * tuned simplifier trace output; new flag debug_simp;
  1102 
  1103 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1104 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1105 
  1106 * AxClass.axclass_tac lost the theory argument;
  1107 
  1108 * tuned current_goals_markers semantics: begin / end goal avoids
  1109 printing empty lines;
  1110 
  1111 * removed prs and prs_fn hook, which was broken because it did not
  1112 include \n in its semantics, forcing writeln to add one
  1113 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1114 string -> unit if you really want to output text without newline;
  1115 
  1116 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1117 plain output, interface builders may have to enable 'isabelle_font'
  1118 mode to get Isabelle font glyphs as before;
  1119 
  1120 * refined token_translation interface; INCOMPATIBILITY: output length
  1121 now of type real instead of int;
  1122 
  1123 * theory loader actions may be traced via new ThyInfo.add_hook
  1124 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1125 your own database of information attached to *whole* theories -- as
  1126 opposed to intra-theory data slots offered via TheoryDataFun;
  1127 
  1128 * proper handling of dangling sort hypotheses (at last!);
  1129 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1130 extra sort hypotheses that can be witnessed from the type signature;
  1131 the force_strip_shyps flag is gone, any remaining shyps are simply
  1132 left in the theorem (with a warning issued by strip_shyps_warning);
  1133 
  1134 
  1135 
  1136 New in Isabelle98-1 (October 1998)
  1137 ----------------------------------
  1138 
  1139 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1140 
  1141 * several changes of automated proof tools;
  1142 
  1143 * HOL: major changes to the inductive and datatype packages, including
  1144 some minor incompatibilities of theory syntax;
  1145 
  1146 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1147 called `inj_on';
  1148 
  1149 * HOL: removed duplicate thms in Arith:
  1150   less_imp_add_less  should be replaced by  trans_less_add1
  1151   le_imp_add_le      should be replaced by  trans_le_add1
  1152 
  1153 * HOL: unary minus is now overloaded (new type constraints may be
  1154 required);
  1155 
  1156 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1157 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1158 now taken as an integer constant.
  1159 
  1160 * Pure: ML function 'theory_of' renamed to 'theory';
  1161 
  1162 
  1163 *** Proof tools ***
  1164 
  1165 * Simplifier:
  1166   1. Asm_full_simp_tac is now more aggressive.
  1167      1. It will sometimes reorient premises if that increases their power to
  1168         simplify.
  1169      2. It does no longer proceed strictly from left to right but may also
  1170         rotate premises to achieve further simplification.
  1171      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1172      old Asm_full_simp_tac in that it does not rotate premises.
  1173   2. The simplifier now knows a little bit about nat-arithmetic.
  1174 
  1175 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1176 allows for selected deletion of wrappers, by introduction of names for
  1177 wrapper functionals.  This implies that addbefore, addSbefore,
  1178 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1179 and that adding two tactics with the same name overwrites the first
  1180 one (emitting a warning).
  1181   type wrapper = (int -> tactic) -> (int -> tactic)
  1182   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1183   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1184   delWrapper, delSWrapper: claset *  string            -> claset
  1185   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1186 
  1187 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1188 semantics; addbefore now affects only the unsafe part of step_tac
  1189 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1190 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1191 by Force_tac;
  1192 
  1193 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1194 compWrapper; added safe wrapper (and access functions for it);
  1195 
  1196 * HOL/split_all_tac is now much faster and fails if there is nothing
  1197 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1198 and the names of the automatically generated variables have changed.
  1199 split_all_tac has moved within claset() from unsafe wrappers to safe
  1200 wrappers, which means that !!-bound variables are split much more
  1201 aggressively, and safe_tac and clarify_tac now split such variables.
  1202 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1203 Note: the same holds for record_split_tac, which does the job of
  1204 split_all_tac for record fields.
  1205 
  1206 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1207 permanently to the default simpset using Addsplits just like
  1208 Addsimps. They can be removed via Delsplits just like
  1209 Delsimps. Lower-case versions are also available.
  1210 
  1211 * HOL/Simplifier: The rule split_if is now part of the default
  1212 simpset. This means that the simplifier will eliminate all occurrences
  1213 of if-then-else in the conclusion of a goal. To prevent this, you can
  1214 either remove split_if completely from the default simpset by
  1215 `Delsplits [split_if]' or remove it in a specific call of the
  1216 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1217 other case splitting rules to/from the default simpset: every datatype
  1218 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1219 t is the name of the datatype).
  1220 
  1221 * Classical reasoner / Simplifier combination: new force_tac (and
  1222 derivatives Force_tac, force) combines rewriting and classical
  1223 reasoning (and whatever other tools) similarly to auto_tac, but is
  1224 aimed to solve the given subgoal completely.
  1225 
  1226 
  1227 *** General ***
  1228 
  1229 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1230 and `goalw': the theory is no longer needed as an explicit argument -
  1231 the current theory context is used; assumptions are no longer returned
  1232 at the ML-level unless one of them starts with ==> or !!; it is
  1233 recommended to convert to these new commands using isatool fixgoal
  1234 (backup your sources first!);
  1235 
  1236 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1237 the current theory context, and 'theory' to lookup stored theories;
  1238 
  1239 * new theory section 'locale' for declaring constants, assumptions and
  1240 definitions that have local scope;
  1241 
  1242 * new theory section 'nonterminals' for purely syntactic types;
  1243 
  1244 * new theory section 'setup' for generic ML setup functions
  1245 (e.g. package initialization);
  1246 
  1247 * the distribution now includes Isabelle icons: see
  1248 lib/logo/isabelle-{small,tiny}.xpm;
  1249 
  1250 * isatool install - install binaries with absolute references to
  1251 ISABELLE_HOME/bin;
  1252 
  1253 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1254 
  1255 * print mode 'emacs' reserved for Isamode;
  1256 
  1257 * support multiple print (ast) translations per constant name;
  1258 
  1259 * theorems involving oracles are now printed with a suffixed [!];
  1260 
  1261 
  1262 *** HOL ***
  1263 
  1264 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1265 
  1266 * HOL/inductive package reorganized and improved: now supports mutual
  1267 definitions such as
  1268 
  1269   inductive EVEN ODD
  1270     intrs
  1271       null "0 : EVEN"
  1272       oddI "n : EVEN ==> Suc n : ODD"
  1273       evenI "n : ODD ==> Suc n : EVEN"
  1274 
  1275 new theorem list "elims" contains an elimination rule for each of the
  1276 recursive sets; inductive definitions now handle disjunctive premises
  1277 correctly (also ZF);
  1278 
  1279 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1280 "mutual_induct" no longer exists - the induction rule is always
  1281 contained in "induct";
  1282 
  1283 
  1284 * HOL/datatype package re-implemented and greatly improved: now
  1285 supports mutually recursive datatypes such as
  1286 
  1287   datatype
  1288     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1289             | SUM ('a aexp) ('a aexp)
  1290             | DIFF ('a aexp) ('a aexp)
  1291             | NUM 'a
  1292   and
  1293     'a bexp = LESS ('a aexp) ('a aexp)
  1294             | AND ('a bexp) ('a bexp)
  1295             | OR ('a bexp) ('a bexp)
  1296 
  1297 as well as indirectly recursive datatypes such as
  1298 
  1299   datatype
  1300     ('a, 'b) term = Var 'a
  1301                   | App 'b ((('a, 'b) term) list)
  1302 
  1303 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1304 induction on mutually / indirectly recursive datatypes.
  1305 
  1306 Primrec equations are now stored in theory and can be accessed via
  1307 <function_name>.simps.
  1308 
  1309 INCOMPATIBILITIES:
  1310 
  1311   - Theories using datatypes must now have theory Datatype as an
  1312     ancestor.
  1313   - The specific <typename>.induct_tac no longer exists - use the
  1314     generic induct_tac instead.
  1315   - natE has been renamed to nat.exhaust - use exhaust_tac
  1316     instead of res_inst_tac ... natE. Note that the variable
  1317     names in nat.exhaust differ from the names in natE, this
  1318     may cause some "fragile" proofs to fail.
  1319   - The theorems split_<typename>_case and split_<typename>_case_asm
  1320     have been renamed to <typename>.split and <typename>.split_asm.
  1321   - Since default sorts of type variables are now handled correctly,
  1322     some datatype definitions may have to be annotated with explicit
  1323     sort constraints.
  1324   - Primrec definitions no longer require function name and type
  1325     of recursive argument.
  1326 
  1327 Consider using isatool fixdatatype to adapt your theories and proof
  1328 scripts to the new package (backup your sources first!).
  1329 
  1330 
  1331 * HOL/record package: considerably improved implementation; now
  1332 includes concrete syntax for record types, terms, updates; theorems
  1333 for surjective pairing and splitting !!-bound record variables; proof
  1334 support is as follows:
  1335 
  1336   1) standard conversions (selectors or updates applied to record
  1337 constructor terms) are part of the standard simpset;
  1338 
  1339   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1340 made part of standard simpset and claset via addIffs;
  1341 
  1342   3) a tactic for record field splitting (record_split_tac) is part of
  1343 the standard claset (addSWrapper);
  1344 
  1345 To get a better idea about these rules you may retrieve them via
  1346 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1347 the name of your record type.
  1348 
  1349 The split tactic 3) conceptually simplifies by the following rule:
  1350 
  1351   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1352 
  1353 Thus any record variable that is bound by meta-all will automatically
  1354 blow up into some record constructor term, consequently the
  1355 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1356 solve record problems automatically.
  1357 
  1358 
  1359 * reorganized the main HOL image: HOL/Integ and String loaded by
  1360 default; theory Main includes everything;
  1361 
  1362 * automatic simplification of integer sums and comparisons, using cancellation;
  1363 
  1364 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1365 
  1366 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1367 
  1368 * many new identities for unions, intersections, set difference, etc.;
  1369 
  1370 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1371 called split_if, split_split, split_sum_case and split_nat_case (to go
  1372 with add/delsplits);
  1373 
  1374 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1375 (?x::unit) = (); this is made part of the default simpset, which COULD
  1376 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1377 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1378 unit_abs_eta_conv is added in order to counter the effect of
  1379 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1380 %u.f();
  1381 
  1382 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1383 makes more sense);
  1384 
  1385 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1386   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1387   disjointness reasoning but breaking a few old proofs.
  1388 
  1389 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1390 to 'converse' from 'inverse' (for compatibility with ZF and some
  1391 literature);
  1392 
  1393 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1394 the well-founded relation;
  1395 
  1396 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1397     Compl A.  The "Compl" syntax remains available as input syntax for this
  1398     release ONLY.
  1399 
  1400 * HOL/Update: new theory of function updates:
  1401     f(a:=b) == %x. if x=a then b else f x
  1402 may also be iterated as in f(a:=b,c:=d,...);
  1403 
  1404 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1405 
  1406 * HOL/List:
  1407   - new function list_update written xs[i:=v] that updates the i-th
  1408     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1409   - new function `upt' written [i..j(] which generates the list
  1410     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1411     bound write [i..j], which is a shorthand for [i..j+1(].
  1412   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1413 
  1414 * HOL/Arith:
  1415   - removed 'pred' (predecessor) function;
  1416   - generalized some theorems about n-1;
  1417   - many new laws about "div" and "mod";
  1418   - new laws about greatest common divisors (see theory ex/Primes);
  1419 
  1420 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1421 instead of "inverse";
  1422 
  1423 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1424   of the multiset ordering;
  1425 
  1426 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1427   (not included by default);
  1428 
  1429 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1430 
  1431 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1432   programs, i.e. different program variables may have different types.
  1433 
  1434 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1435   [previously, this check worked only if the rewrite rule was unconditional]
  1436   Now rew can involve either definitions or equalities (either == or =).
  1437 
  1438 
  1439 *** ZF ***
  1440 
  1441 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1442   only the theorems proved on ZF.ML;
  1443 
  1444 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1445   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1446   disjointness reasoning but breaking a few old proofs.
  1447 
  1448 * ZF/Update: new theory of function updates
  1449     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1450   may also be iterated as in f(a:=b,c:=d,...);
  1451 
  1452 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1453 
  1454 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1455   [previously, this check worked only if the rewrite rule was unconditional]
  1456   Now rew can involve either definitions or equalities (either == or =).
  1457 
  1458 * case_tac provided for compatibility with HOL
  1459     (like the old excluded_middle_tac, but with subgoals swapped)
  1460 
  1461 
  1462 *** Internal programming interfaces ***
  1463 
  1464 * Pure: several new basic modules made available for general use, see
  1465 also src/Pure/README;
  1466 
  1467 * improved the theory data mechanism to support encapsulation (data
  1468 kind name replaced by private Object.kind, acting as authorization
  1469 key); new type-safe user interface via functor TheoryDataFun; generic
  1470 print_data function becomes basically useless;
  1471 
  1472 * removed global_names compatibility flag -- all theory declarations
  1473 are qualified by default;
  1474 
  1475 * module Pure/Syntax now offers quote / antiquote translation
  1476 functions (useful for Hoare logic etc. with implicit dependencies);
  1477 see HOL/ex/Antiquote for an example use;
  1478 
  1479 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1480 cterm -> thm;
  1481 
  1482 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1483 subgoal;
  1484 
  1485 * Display.print_goals function moved to Locale.print_goals;
  1486 
  1487 * standard print function for goals supports current_goals_markers
  1488 variable for marking begin of proof, end of proof, start of goal; the
  1489 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1490 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1491 for example;
  1492 
  1493 
  1494 
  1495 New in Isabelle98 (January 1998)
  1496 --------------------------------
  1497 
  1498 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1499 
  1500 * changed lexical syntax of terms / types: dots made part of long
  1501 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1502 
  1503 * simpset (and claset) reference variable replaced by functions
  1504 simpset / simpset_ref;
  1505 
  1506 * no longer supports theory aliases (via merge) and non-trivial
  1507 implicit merge of thms' signatures;
  1508 
  1509 * most internal names of constants changed due to qualified names;
  1510 
  1511 * changed Pure/Sequence interface (see Pure/seq.ML);
  1512 
  1513 
  1514 *** General Changes ***
  1515 
  1516 * hierachically structured name spaces (for consts, types, axms, thms
  1517 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1518 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1519 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1520 long_names for fully qualified output names; NOTE: ML programs
  1521 (special tactics, packages etc.) referring to internal names may have
  1522 to be adapted to cope with fully qualified names; in case of severe
  1523 backward campatibility problems try setting 'global_names' at compile
  1524 time to have enrything declared within a flat name space; one may also
  1525 fine tune name declarations in theories via the 'global' and 'local'
  1526 section;
  1527 
  1528 * reimplemented the implicit simpset and claset using the new anytype
  1529 data filed in signatures; references simpset:simpset ref etc. are
  1530 replaced by functions simpset:unit->simpset and
  1531 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1532 to patch your ML files accordingly;
  1533 
  1534 * HTML output now includes theory graph data for display with Java
  1535 applet or isatool browser; data generated automatically via isatool
  1536 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1537 
  1538 * defs may now be conditional; improved rewrite_goals_tac to handle
  1539 conditional equations;
  1540 
  1541 * defs now admits additional type arguments, using TYPE('a) syntax;
  1542 
  1543 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1544 creates a new theory node; implicit merge of thms' signatures is
  1545 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1546 transfer:theory->thm->thm in (rare) cases;
  1547 
  1548 * improved handling of draft signatures / theories; draft thms (and
  1549 ctyps, cterms) are automatically promoted to real ones;
  1550 
  1551 * slightly changed interfaces for oracles: admit many per theory, named
  1552 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1553 
  1554 * print_goals: optional output of const types (set show_consts and
  1555 show_types);
  1556 
  1557 * improved output of warnings (###) and errors (***);
  1558 
  1559 * subgoal_tac displays a warning if the new subgoal has type variables;
  1560 
  1561 * removed old README and Makefiles;
  1562 
  1563 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1564 
  1565 * removed obsolete init_pps and init_database;
  1566 
  1567 * deleted the obsolete tactical STATE, which was declared by
  1568     fun STATE tacfun st = tacfun st st;
  1569 
  1570 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1571 (which abbreviates $HOME);
  1572 
  1573 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1574 use isatool fixseq to adapt your ML programs (this works for fully
  1575 qualified references to the Sequence structure only!);
  1576 
  1577 * use_thy no longer requires writable current directory; it always
  1578 reloads .ML *and* .thy file, if either one is out of date;
  1579 
  1580 
  1581 *** Classical Reasoner ***
  1582 
  1583 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1584 tactics that use classical reasoning to simplify a subgoal without
  1585 splitting it into several subgoals;
  1586 
  1587 * Safe_tac: like safe_tac but uses the default claset;
  1588 
  1589 
  1590 *** Simplifier ***
  1591 
  1592 * added simplification meta rules:
  1593     (asm_)(full_)simplify: simpset -> thm -> thm;
  1594 
  1595 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1596 logics (again);
  1597 
  1598 * added prems argument to simplification procedures;
  1599 
  1600 * HOL, FOL, ZF: added infix function `addsplits':
  1601   instead of `<simpset> setloop (split_tac <thms>)'
  1602   you can simply write `<simpset> addsplits <thms>'
  1603 
  1604 
  1605 *** Syntax ***
  1606 
  1607 * TYPE('a) syntax for type reflection terms;
  1608 
  1609 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1610 
  1611 * pretty printer: changed order of mixfix annotation preference (again!);
  1612 
  1613 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1614 
  1615 
  1616 *** HOL ***
  1617 
  1618 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1619   with `addloop' of the simplifier to faciliate case splitting in premises.
  1620 
  1621 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1622 
  1623 * HOL/Auth: new protocol proofs including some for the Internet
  1624   protocol TLS;
  1625 
  1626 * HOL/Map: new theory of `maps' a la VDM;
  1627 
  1628 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1629 cancelling out common nat summands from =, <, <= (in)equalities, or
  1630 differences; simplification procedures nat_cancel_factor for
  1631 cancelling common factor from =, <, <= (in)equalities over natural
  1632 sums; nat_cancel contains both kinds of procedures, it is installed by
  1633 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1634 
  1635 * HOL/simplifier: terms of the form
  1636   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1637   are rewritten to
  1638   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1639   and those of the form
  1640   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1641   are rewritten to
  1642   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1643 
  1644 * HOL/datatype
  1645   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1646 
  1647   P(t_case f1 ... fn x) =
  1648      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1649         ...
  1650        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1651      )
  1652 
  1653   and a theorem `split_t_case_asm' of the form
  1654 
  1655   P(t_case f1 ... fn x) =
  1656     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1657         ...
  1658        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1659      )
  1660   which can be added to a simpset via `addsplits'. The existing theorems
  1661   expand_list_case and expand_option_case have been renamed to
  1662   split_list_case and split_option_case.
  1663 
  1664 * HOL/Arithmetic:
  1665   - `pred n' is automatically converted to `n-1'.
  1666     Users are strongly encouraged not to use `pred' any longer,
  1667     because it will disappear altogether at some point.
  1668   - Users are strongly encouraged to write "0 < n" rather than
  1669     "n ~= 0". Theorems and proof tools have been modified towards this
  1670     `standard'.
  1671 
  1672 * HOL/Lists:
  1673   the function "set_of_list" has been renamed "set" (and its theorems too);
  1674   the function "nth" now takes its arguments in the reverse order and
  1675   has acquired the infix notation "!" as in "xs!n".
  1676 
  1677 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1678 
  1679 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1680   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1681 
  1682 * HOL/record: extensible records with schematic structural subtyping
  1683 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1684 still lacks various theorems and concrete record syntax;
  1685 
  1686 
  1687 *** HOLCF ***
  1688 
  1689 * removed "axioms" and "generated by" sections;
  1690 
  1691 * replaced "ops" section by extended "consts" section, which is capable of
  1692   handling the continuous function space "->" directly;
  1693 
  1694 * domain package:
  1695   . proves theorems immediately and stores them in the theory,
  1696   . creates hierachical name space,
  1697   . now uses normal mixfix annotations (instead of cinfix...),
  1698   . minor changes to some names and values (for consistency),
  1699   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1700   . separator between mutual domain defs: changed "," to "and",
  1701   . improved handling of sort constraints;  now they have to
  1702     appear on the left-hand side of the equations only;
  1703 
  1704 * fixed LAM <x,y,zs>.b syntax;
  1705 
  1706 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1707 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1708 
  1709 
  1710 *** FOL and ZF ***
  1711 
  1712 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1713   with `addloop' of the simplifier to faciliate case splitting in premises.
  1714 
  1715 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1716 in HOL, they strip ALL and --> from proved theorems;
  1717 
  1718 
  1719 
  1720 New in Isabelle94-8 (May 1997)
  1721 ------------------------------
  1722 
  1723 *** General Changes ***
  1724 
  1725 * new utilities to build / run / maintain Isabelle etc. (in parts
  1726 still somewhat experimental); old Makefiles etc. still functional;
  1727 
  1728 * new 'Isabelle System Manual';
  1729 
  1730 * INSTALL text, together with ./configure and ./build scripts;
  1731 
  1732 * reimplemented type inference for greater efficiency, better error
  1733 messages and clean internal interface;
  1734 
  1735 * prlim command for dealing with lots of subgoals (an easier way of
  1736 setting goals_limit);
  1737 
  1738 
  1739 *** Syntax ***
  1740 
  1741 * supports alternative (named) syntax tables (parser and pretty
  1742 printer); internal interface is provided by add_modesyntax(_i);
  1743 
  1744 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1745 be used in conjunction with the Isabelle symbol font; uses the
  1746 "symbols" syntax table;
  1747 
  1748 * added token_translation interface (may translate name tokens in
  1749 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1750 the current print_mode); IMPORTANT: user print translation functions
  1751 are responsible for marking newly introduced bounds
  1752 (Syntax.mark_boundT);
  1753 
  1754 * token translations for modes "xterm" and "xterm_color" that display
  1755 names in bold, underline etc. or colors (which requires a color
  1756 version of xterm);
  1757 
  1758 * infixes may now be declared with names independent of their syntax;
  1759 
  1760 * added typed_print_translation (like print_translation, but may
  1761 access type of constant);
  1762 
  1763 
  1764 *** Classical Reasoner ***
  1765 
  1766 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1767 some limitations.  Blast_tac...
  1768   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1769   + ignores elimination rules that don't have the correct format
  1770         (the conclusion MUST be a formula variable)
  1771   + ignores types, which can make HOL proofs fail
  1772   + rules must not require higher-order unification, e.g. apply_type in ZF
  1773     [message "Function Var's argument not a bound variable" relates to this]
  1774   + its proof strategy is more general but can actually be slower
  1775 
  1776 * substitution with equality assumptions no longer permutes other
  1777 assumptions;
  1778 
  1779 * minor changes in semantics of addafter (now called addaltern); renamed
  1780 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1781 (and access functions for it);
  1782 
  1783 * improved combination of classical reasoner and simplifier:
  1784   + functions for handling clasimpsets
  1785   + improvement of addss: now the simplifier is called _after_ the
  1786     safe steps.
  1787   + safe variant of addss called addSss: uses safe simplifications
  1788     _during_ the safe steps. It is more complete as it allows multiple
  1789     instantiations of unknowns (e.g. with slow_tac).
  1790 
  1791 *** Simplifier ***
  1792 
  1793 * added interface for simplification procedures (functions that
  1794 produce *proven* rewrite rules on the fly, depending on current
  1795 redex);
  1796 
  1797 * ordering on terms as parameter (used for ordered rewriting);
  1798 
  1799 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1800 
  1801 * the solver is now split into a safe and an unsafe part.
  1802 This should be invisible for the normal user, except that the
  1803 functions setsolver and addsolver have been renamed to setSolver and
  1804 addSolver; added safe_asm_full_simp_tac;
  1805 
  1806 
  1807 *** HOL ***
  1808 
  1809 * a generic induction tactic `induct_tac' which works for all datatypes and
  1810 also for type `nat';
  1811 
  1812 * a generic case distinction tactic `exhaust_tac' which works for all
  1813 datatypes and also for type `nat';
  1814 
  1815 * each datatype comes with a function `size';
  1816 
  1817 * patterns in case expressions allow tuple patterns as arguments to
  1818 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1819 
  1820 * primrec now also works with type nat;
  1821 
  1822 * recdef: a new declaration form, allows general recursive functions to be
  1823 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1824 
  1825 * the constant for negation has been renamed from "not" to "Not" to
  1826 harmonize with FOL, ZF, LK, etc.;
  1827 
  1828 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1829 infinite lists;
  1830 
  1831 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1832 
  1833 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1834 problems in commutative rings, using axiomatic type classes for + and *;
  1835 
  1836 * more examples in HOL/MiniML and HOL/Auth;
  1837 
  1838 * more default rewrite rules for quantifiers, union/intersection;
  1839 
  1840 * a new constant `arbitrary == @x.False';
  1841 
  1842 * HOLCF/IOA replaces old HOL/IOA;
  1843 
  1844 * HOLCF changes: derived all rules and arities
  1845   + axiomatic type classes instead of classes
  1846   + typedef instead of faking type definitions
  1847   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1848   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1849   + eliminated the types void, one, tr
  1850   + use unit lift and bool lift (with translations) instead of one and tr
  1851   + eliminated blift from Lift3.thy (use Def instead of blift)
  1852   all eliminated rules are derived as theorems --> no visible changes ;
  1853 
  1854 
  1855 *** ZF ***
  1856 
  1857 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1858 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1859 as ZF_cs addSIs [equalityI];
  1860 
  1861 
  1862 
  1863 New in Isabelle94-7 (November 96)
  1864 ---------------------------------
  1865 
  1866 * allowing negative levels (as offsets) in prlev and choplev;
  1867 
  1868 * super-linear speedup for large simplifications;
  1869 
  1870 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1871 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1872 FAIL); can suppress it using the command Delsimps (ex_simps @
  1873 all_simps); De Morgan laws are also now included, by default;
  1874 
  1875 * improved printing of ==>  :  ~:
  1876 
  1877 * new object-logic "Sequents" adds linear logic, while replacing LK
  1878 and Modal (thanks to Sara Kalvala);
  1879 
  1880 * HOL/Auth: correctness proofs for authentication protocols;
  1881 
  1882 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1883 examples on HOL/Auth);
  1884 
  1885 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1886 the rewriter and classical reasoner simultaneously;
  1887 
  1888 * function uresult no longer returns theorems in "standard" format;
  1889 regain previous version by: val uresult = standard o uresult;
  1890 
  1891 
  1892 
  1893 New in Isabelle94-6
  1894 -------------------
  1895 
  1896 * oracles -- these establish an interface between Isabelle and trusted
  1897 external reasoners, which may deliver results as theorems;
  1898 
  1899 * proof objects (in particular record all uses of oracles);
  1900 
  1901 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1902 
  1903 * "constdefs" section in theory files;
  1904 
  1905 * "primrec" section (HOL) no longer requires names;
  1906 
  1907 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1908 
  1909 
  1910 
  1911 New in Isabelle94-5
  1912 -------------------
  1913 
  1914 * reduced space requirements;
  1915 
  1916 * automatic HTML generation from theories;
  1917 
  1918 * theory files no longer require "..." (quotes) around most types;
  1919 
  1920 * new examples, including two proofs of the Church-Rosser theorem;
  1921 
  1922 * non-curried (1994) version of HOL is no longer distributed;
  1923 
  1924 
  1925 
  1926 New in Isabelle94-4
  1927 -------------------
  1928 
  1929 * greatly reduced space requirements;
  1930 
  1931 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1932 
  1933 * searchable theorem database (see the section "Retrieving theorems" on
  1934 page 8 of the Reference Manual);
  1935 
  1936 * new examples, including Grabczewski's monumental case study of the
  1937 Axiom of Choice;
  1938 
  1939 * The previous version of HOL renamed to Old_HOL;
  1940 
  1941 * The new version of HOL (previously called CHOL) uses a curried syntax
  1942 for functions.  Application looks like f a b instead of f(a,b);
  1943 
  1944 * Mutually recursive inductive definitions finally work in HOL;
  1945 
  1946 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1947 translates to the operator "split";
  1948 
  1949 
  1950 
  1951 New in Isabelle94-3
  1952 -------------------
  1953 
  1954 * new infix operator, addss, allowing the classical reasoner to
  1955 perform simplification at each step of its search.  Example:
  1956         fast_tac (cs addss ss)
  1957 
  1958 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1959 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1960 look like (a,b) instead of <a,b>;
  1961 
  1962 * PLEASE NOTE: CHOL will eventually replace HOL!
  1963 
  1964 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1965 It translates to the operator "split".  A new theory of integers is available;
  1966 
  1967 * In ZF, integer numerals now denote two's-complement binary integers.
  1968 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1969 
  1970 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1971 of the Axiom of Choice;
  1972 
  1973 
  1974 
  1975 New in Isabelle94-2
  1976 -------------------
  1977 
  1978 * Significantly faster resolution;
  1979 
  1980 * the different sections in a .thy file can now be mixed and repeated
  1981 freely;
  1982 
  1983 * Database of theorems for FOL, HOL and ZF.  New
  1984 commands including qed, qed_goal and bind_thm store theorems in the database.
  1985 
  1986 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1987 a given theory (thms_of), or find out what theory a theorem was proved in
  1988 (theory_of_thm);
  1989 
  1990 * Bugs fixed in the inductive definition and datatype packages;
  1991 
  1992 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1993 and HOL_dup_cs obsolete;
  1994 
  1995 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1996 have been removed;
  1997 
  1998 * Simpler definition of function space in ZF;
  1999 
  2000 * new results about cardinal and ordinal arithmetic in ZF;
  2001 
  2002 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2003 types;
  2004 
  2005 
  2006 $Id$