NEWS
author wenzelm
Tue Sep 04 21:10:57 2001 +0200 (2001-09-04)
changeset 11549 e7265e70fd7c
parent 11542 2afde2de26d6
child 11551 8b5064d1c5c9
permissions -rw-r--r--
renamed "antecedent" case to "rule_context";
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2001 (?? 2001)
     6 -----------------------------
     7 
     8 *** Isar ***
     9 
    10 * renamed "antecedent" case to "rule_context";
    11 
    12 
    13 *** HOL ***
    14 
    15 * HOL: added "The" definite description operator;
    16 
    17 * HOL: made split_all_tac safe. EXISTING PROOFS MAY FAIL OR LOOP, so in this
    18   (rare) case use   delSWrapper "split_all_tac" addSbefore 
    19                     ("unsafe_split_all_tac", unsafe_split_all_tac)
    20 
    21 * HOL: added safe wrapper "split_conv_tac" to claset.  EXISTING PROOFS
    22 MAY FAIL;
    23 
    24 * Classical reasoner: renamed addaltern to addafter, addSaltern to addSafter
    25 
    26 * HOL: introduced f^n = f o ... o f
    27   WARNING: due to the limits of Isabelle's type classes, ^ on functions and
    28   relations has too general a domain, namely ('a * 'b)set and 'a => 'b.
    29   This means that it may be necessary to attach explicit type constraints.
    30 
    31 * HOL: syntax translations now work properly with numerals and records
    32 expressions;
    33 
    34 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
    35 Florian Kammüller;
    36 
    37 
    38 *** ZF ***
    39 
    40 * ZF: the integer library now covers quotients and remainders, with
    41 many laws relating division to addition, multiplication, etc.;
    42 
    43 
    44 *** General ***
    45 
    46 * Classical reasoner: renamed addaltern to addafter, addSaltern to
    47 addSafter;
    48 
    49 * print modes "type_brackets" and "no_type_brackets" control output of
    50 nested => (types); the default behaviour is "brackets";
    51 
    52 * Proof General keywords specification is now part of the Isabelle
    53 distribution (see etc/isar-keywords.el);
    54 
    55 
    56 
    57 New in Isabelle99-2 (February 2001)
    58 -----------------------------------
    59 
    60 *** Overview of INCOMPATIBILITIES ***
    61 
    62 * HOL: please note that theories in the Library and elsewhere often use the
    63 new-style (Isar) format; to refer to their theorems in an ML script you must
    64 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
    65 
    66 * HOL: inductive package no longer splits induction rule aggressively,
    67 but only as far as specified by the introductions given; the old
    68 format may be recovered via ML function complete_split_rule or attribute
    69 'split_rule (complete)';
    70 
    71 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
    72 gfp_Tarski to gfp_unfold;
    73 
    74 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
    75 
    76 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
    77 relation); infix "^^" has been renamed "``"; infix "``" has been
    78 renamed "`"; "univalent" has been renamed "single_valued";
    79 
    80 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
    81 operation;
    82 
    83 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
    84 
    85 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
    86 
    87 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
    88 consequence, it is no longer monotonic wrt. the local goal context
    89 (which is now passed through the inductive cases);
    90 
    91 * Document preparation: renamed standard symbols \<ll> to \<lless> and
    92 \<gg> to \<ggreater>;
    93 
    94 
    95 *** Document preparation ***
    96 
    97 * \isabellestyle{NAME} selects version of Isabelle output (currently
    98 available: are "it" for near math-mode best-style output, "sl" for
    99 slanted text style, and "tt" for plain type-writer; if no
   100 \isabellestyle command is given, output is according to slanted
   101 type-writer);
   102 
   103 * support sub/super scripts (for single symbols only), input syntax is
   104 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   105 
   106 * some more standard symbols; see Appendix A of the system manual for
   107 the complete list of symbols defined in isabellesym.sty;
   108 
   109 * improved isabelle style files; more abstract symbol implementation
   110 (should now use \isamath{...} and \isatext{...} in custom symbol
   111 definitions);
   112 
   113 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   114 state; Note that presentation of goal states does not conform to
   115 actual human-readable proof documents.  Please do not include goal
   116 states into document output unless you really know what you are doing!
   117 
   118 * proper indentation of antiquoted output with proportional LaTeX
   119 fonts;
   120 
   121 * no_document ML operator temporarily disables LaTeX document
   122 generation;
   123 
   124 * isatool unsymbolize tunes sources for plain ASCII communication;
   125 
   126 
   127 *** Isar ***
   128 
   129 * Pure: Isar now suffers initial goal statements to contain unbound
   130 schematic variables (this does not conform to actual readable proof
   131 documents, due to unpredictable outcome and non-compositional proof
   132 checking); users who know what they are doing may use schematic goals
   133 for Prolog-style synthesis of proven results;
   134 
   135 * Pure: assumption method (an implicit finishing) now handles actual
   136 rules as well;
   137 
   138 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   139 initial goal, declare "that" only as Pure intro (only for single
   140 steps); the "that" rule assumption may now be involved in implicit
   141 finishing, thus ".." becomes a feasible for trivial obtains;
   142 
   143 * Pure: default proof step now includes 'intro_classes'; thus trivial
   144 instance proofs may be performed by "..";
   145 
   146 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   147 statements as well;
   148 
   149 * Pure: more robust selection of calculational rules;
   150 
   151 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   152 rule (as well as the assumption rule);
   153 
   154 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   155 lemmas, using the graph browser tool;
   156 
   157 * Pure: predict failure of "show" in interactive mode;
   158 
   159 * Pure: 'thms_containing' now takes actual terms as arguments;
   160 
   161 * HOL: improved method 'induct' --- now handles non-atomic goals
   162 (potential INCOMPATIBILITY); tuned error handling;
   163 
   164 * HOL: cases and induct rules now provide explicit hints about the
   165 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   166 any remaining facts are inserted into the goal verbatim;
   167 
   168 * HOL: local contexts (aka cases) may now contain term bindings as
   169 well; the 'cases' and 'induct' methods new provide a ?case binding for
   170 the result to be shown in each case;
   171 
   172 * HOL: added 'recdef_tc' command;
   173 
   174 * isatool convert assists in eliminating legacy ML scripts;
   175 
   176 
   177 *** HOL ***
   178 
   179 * HOL/Library: a collection of generic theories to be used together
   180 with main HOL; the theory loader path already includes this directory
   181 by default; the following existing theories have been moved here:
   182 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   183 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   184 
   185 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   186 modelling and verification task performed in Isabelle/HOL +
   187 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   188 
   189 * HOL/Algebra: special summation operator SUM no longer exists, it has
   190 been replaced by setsum; infix 'assoc' now has priority 50 (like
   191 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   192 'domain', this makes the theory consistent with mathematical
   193 literature;
   194 
   195 * HOL basics: added overloaded operations "inverse" and "divide"
   196 (infix "/"), syntax for generic "abs" operation, generic summation
   197 operator \<Sum>;
   198 
   199 * HOL/typedef: simplified package, provide more useful rules (see also
   200 HOL/subset.thy);
   201 
   202 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   203 now expressed as a proper nested rule (old-style tactic scripts may
   204 require atomize_strip_tac to cope with non-atomic premises);
   205 
   206 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   207 to "split_conv" (old name still available for compatibility);
   208 
   209 * HOL: improved concrete syntax for strings (e.g. allows translation
   210 rules with string literals);
   211 
   212 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   213 and Fleuriot's mechanization of analysis;
   214 
   215 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   216 
   217 
   218 *** CTT ***
   219 
   220 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   221 "lam" is displayed as TWO lambda-symbols
   222 
   223 * CTT: theory Main now available, containing everything (that is, Bool
   224 and Arith);
   225 
   226 
   227 *** General ***
   228 
   229 * Pure: the Simplifier has been implemented properly as a derived rule
   230 outside of the actual kernel (at last!); the overall performance
   231 penalty in practical applications is about 50%, while reliability of
   232 the Isabelle inference kernel has been greatly improved;
   233 
   234 * print modes "brackets" and "no_brackets" control output of nested =>
   235 (types) and ==> (props); the default behaviour is "brackets";
   236 
   237 * Provers: fast_tac (and friends) now handle actual object-logic rules
   238 as assumptions as well;
   239 
   240 * system: support Poly/ML 4.0;
   241 
   242 * system: isatool install handles KDE version 1 or 2;
   243 
   244 
   245 
   246 New in Isabelle99-1 (October 2000)
   247 ----------------------------------
   248 
   249 *** Overview of INCOMPATIBILITIES ***
   250 
   251 * HOL: simplification of natural numbers is much changed; to partly
   252 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   253 issue the following ML commands:
   254 
   255   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   256   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   257 
   258 * HOL: simplification no longer dives into case-expressions; this is
   259 controlled by "t.weak_case_cong" for each datatype t;
   260 
   261 * HOL: nat_less_induct renamed to less_induct;
   262 
   263 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   264 fixsome to patch .thy and .ML sources automatically;
   265 
   266   select_equality  -> some_equality
   267   select_eq_Ex     -> some_eq_ex
   268   selectI2EX       -> someI2_ex
   269   selectI2         -> someI2
   270   selectI          -> someI
   271   select1_equality -> some1_equality
   272   Eps_sym_eq       -> some_sym_eq_trivial
   273   Eps_eq           -> some_eq_trivial
   274 
   275 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   276 
   277 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   278 instead);
   279 
   280 * HOL: the recursion equations generated by 'recdef' are now called
   281 f.simps instead of f.rules;
   282 
   283 * HOL: qed_spec_mp now also handles bounded ALL as well;
   284 
   285 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   286 sometimes be needed;
   287 
   288 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   289 
   290 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   291 
   292 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   293 product is now "<*>" instead of "Times"; the lexicographic product is
   294 now "<*lex*>" instead of "**";
   295 
   296 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   297 of main HOL, but was unused); better use HOL's datatype package;
   298 
   299 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   300 the old syntax may be recovered as follows:
   301 
   302   syntax (symbols)
   303     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   304       (infixl "\\<oplus>" 100)
   305 
   306 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   307 
   308 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   309 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   310 internally;
   311 
   312 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   313 changed from A/r to A//r;
   314 
   315 * ZF: new treatment of arithmetic (nat & int) may break some old
   316 proofs;
   317 
   318 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   319 rulify -> rule_format, elimify -> elim_format, ...);
   320 
   321 * Isar/Provers: intro/elim/dest attributes changed; renamed
   322 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   323 should have to change intro!! to intro? only); replaced "delrule" by
   324 "rule del";
   325 
   326 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   327 
   328 * Provers: strengthened force_tac by using new first_best_tac;
   329 
   330 * LaTeX document preparation: several changes of isabelle.sty (see
   331 lib/texinputs);
   332 
   333 
   334 *** Document preparation ***
   335 
   336 * formal comments (text blocks etc.) in new-style theories may now
   337 contain antiquotations of thm/prop/term/typ/text to be presented
   338 according to latex print mode; concrete syntax is like this:
   339 @{term[show_types] "f(x) = a + x"};
   340 
   341 * isatool mkdir provides easy setup of Isabelle session directories,
   342 including proper document sources;
   343 
   344 * generated LaTeX sources are now deleted after successful run
   345 (isatool document -c); may retain a copy somewhere else via -D option
   346 of isatool usedir;
   347 
   348 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   349 style files, achieving self-contained LaTeX sources and simplifying
   350 LaTeX debugging;
   351 
   352 * old-style theories now produce (crude) LaTeX output as well;
   353 
   354 * browser info session directories are now self-contained (may be put
   355 on WWW server seperately); improved graphs of nested sessions; removed
   356 graph for 'all sessions';
   357 
   358 * several improvements in isabelle style files; \isabellestyle{it}
   359 produces fake math mode output; \isamarkupheader is now \section by
   360 default; see lib/texinputs/isabelle.sty etc.;
   361 
   362 
   363 *** Isar ***
   364 
   365 * Isar/Pure: local results and corresponding term bindings are now
   366 subject to Hindley-Milner polymorphism (similar to ML); this
   367 accommodates incremental type-inference very nicely;
   368 
   369 * Isar/Pure: new derived language element 'obtain' supports
   370 generalized existence reasoning;
   371 
   372 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   373 support accumulation of results, without applying any rules yet;
   374 useful to collect intermediate results without explicit name
   375 references, and for use with transitivity rules with more than 2
   376 premises;
   377 
   378 * Isar/Pure: scalable support for case-analysis type proofs: new
   379 'case' language element refers to local contexts symbolically, as
   380 produced by certain proof methods; internally, case names are attached
   381 to theorems as "tags";
   382 
   383 * Isar/Pure: theory command 'hide' removes declarations from
   384 class/type/const name spaces;
   385 
   386 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   387 indicate potential overloading;
   388 
   389 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   390 
   391 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   392 "{a,b,c}" instead of {a,b,c};
   393 
   394 * Isar/Pure now provides its own version of intro/elim/dest
   395 attributes; useful for building new logics, but beware of confusion
   396 with the version in Provers/classical;
   397 
   398 * Isar/Pure: the local context of (non-atomic) goals is provided via
   399 case name 'antecedent';
   400 
   401 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   402 to the current context is now done automatically);
   403 
   404 * Isar/Pure: theory command 'method_setup' provides a simple interface
   405 for definining proof methods in ML;
   406 
   407 * Isar/Provers: intro/elim/dest attributes changed; renamed
   408 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   409 most cases, one should have to change intro!! to intro? only);
   410 replaced "delrule" by "rule del";
   411 
   412 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   413 'symmetric' attribute (the latter supercedes [RS sym]);
   414 
   415 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   416 method modifier); 'simp' method: 'only:' modifier removes loopers as
   417 well (including splits);
   418 
   419 * Isar/Provers: Simplifier and Classical methods now support all kind
   420 of modifiers used in the past, including 'cong', 'iff', etc.
   421 
   422 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   423 of Simplifier and Classical reasoner);
   424 
   425 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   426 now support named cases; major packages (inductive, datatype, primrec,
   427 recdef) support case names and properly name parameters;
   428 
   429 * Isar/HOL: new transitivity rules for substitution in inequalities --
   430 monotonicity conditions are extracted to be proven at end of
   431 calculations;
   432 
   433 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   434 method anyway;
   435 
   436 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   437 split_if split_if_asm; datatype package provides theorems foo.splits =
   438 foo.split foo.split_asm for each datatype;
   439 
   440 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   441 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   442 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   443 use "(cases (simplified))" method in proper proof texts);
   444 
   445 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   446 
   447 * Isar: names of theorems etc. may be natural numbers as well;
   448 
   449 * Isar: 'pr' command: optional arguments for goals_limit and
   450 ProofContext.prems_limit; no longer prints theory contexts, but only
   451 proof states;
   452 
   453 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   454 additional print modes to be specified; e.g. "pr(latex)" will print
   455 proof state according to the Isabelle LaTeX style;
   456 
   457 * Isar: improved support for emulating tactic scripts, including proof
   458 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   459 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   460 (for HOL datatypes);
   461 
   462 * Isar: simplified (more robust) goal selection of proof methods: 1st
   463 goal, all goals, or explicit goal specifier (tactic emulation); thus
   464 'proof method scripts' have to be in depth-first order;
   465 
   466 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   467 
   468 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   469 should instead use individual commands for printing items
   470 (print_commands, print_methods etc.);
   471 
   472 * Isar: added 'nothing' --- the empty list of theorems;
   473 
   474 
   475 *** HOL ***
   476 
   477 * HOL/MicroJava: formalization of a fragment of Java, together with a
   478 corresponding virtual machine and a specification of its bytecode
   479 verifier and a lightweight bytecode verifier, including proofs of
   480 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   481 Cornelia Pusch (see also the homepage of project Bali at
   482 http://isabelle.in.tum.de/Bali/);
   483 
   484 * HOL/Algebra: new theory of rings and univariate polynomials, by
   485 Clemens Ballarin;
   486 
   487 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   488 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   489 Rasmussen;
   490 
   491 * HOL/Lattice: fundamental concepts of lattice theory and order
   492 structures, including duals, properties of bounds versus algebraic
   493 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   494 Theorem for complete lattices etc.; may also serve as a demonstration
   495 for abstract algebraic reasoning using axiomatic type classes, and
   496 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   497 
   498 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   499 von Oheimb;
   500 
   501 * HOL/IMPP: extension of IMP with local variables and mutually
   502 recursive procedures, by David von Oheimb;
   503 
   504 * HOL/Lambda: converted into new-style theory and document;
   505 
   506 * HOL/ex/Multiquote: example of multiple nested quotations and
   507 anti-quotations -- basically a generalized version of de-Bruijn
   508 representation; very useful in avoiding lifting of operations;
   509 
   510 * HOL/record: added general record equality rule to simpset; fixed
   511 select-update simplification procedure to handle extended records as
   512 well; admit "r" as field name;
   513 
   514 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   515 other numeric types and also as the identity of groups, rings, etc.;
   516 
   517 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   518 Types nat and int belong to this axclass;
   519 
   520 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   521    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   522    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   523   two terms #m*u and #n*u are replaced by #(m+n)*u
   524     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   525   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   526     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   527 
   528 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   529 powerful prover for predicate logic but knows nothing of clasets; see
   530 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   531 
   532 * HOL: new version of "case_tac" subsumes both boolean case split and
   533 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   534 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   535 
   536 * HOL: simplification no longer dives into case-expressions: only the
   537 selector expression is simplified, but not the remaining arms; to
   538 enable full simplification of case-expressions for datatype t, you may
   539 remove t.weak_case_cong from the simpset, either globally (Delcongs
   540 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   541 
   542 * HOL/recdef: the recursion equations generated by 'recdef' for
   543 function 'f' are now called f.simps instead of f.rules; if all
   544 termination conditions are proved automatically, these simplification
   545 rules are added to the simpset, as in primrec; rules may be named
   546 individually as well, resulting in a separate list of theorems for
   547 each equation;
   548 
   549 * HOL/While is a new theory that provides a while-combinator. It
   550 permits the definition of tail-recursive functions without the
   551 provision of a termination measure. The latter is necessary once the
   552 invariant proof rule for while is applied.
   553 
   554 * HOL: new (overloaded) notation for the set of elements below/above
   555 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   556 
   557 * HOL: theorems impI, allI, ballI bound as "strip";
   558 
   559 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   560 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   561 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   562 
   563 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   564 
   565 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   566 main HOL, but was unused);
   567 
   568 * HOL: fewer consts declared as global (e.g. have to refer to
   569 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   570 
   571 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   572 in case of overlap with user translations (e.g. judgements over
   573 tuples); (note that the underlying logical represenation is still
   574 bogus);
   575 
   576 
   577 *** ZF ***
   578 
   579 * ZF: simplification automatically cancels common terms in arithmetic
   580 expressions over nat and int;
   581 
   582 * ZF: new treatment of nat to minimize type-checking: all operators
   583 coerce their operands to a natural number using the function natify,
   584 making the algebraic laws unconditional;
   585 
   586 * ZF: as above, for int: operators coerce their operands to an integer
   587 using the function intify;
   588 
   589 * ZF: the integer library now contains many of the usual laws for the
   590 orderings, including $<=, and monotonicity laws for $+ and $*;
   591 
   592 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   593 simplification;
   594 
   595 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   596 to the simplifier and classical reasoner simultaneously;
   597 
   598 
   599 *** General ***
   600 
   601 * Provers: blast_tac now handles actual object-logic rules as
   602 assumptions; note that auto_tac uses blast_tac internally as well;
   603 
   604 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   605 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   606 
   607 * Provers: delrules now handles destruct rules as well (no longer need
   608 explicit make_elim);
   609 
   610 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   611   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   612 use instead the strong form,
   613   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   614 in HOL, FOL and ZF the function cla_make_elim will create such rules
   615 from destruct-rules;
   616 
   617 * Provers: Simplifier.easy_setup provides a fast path to basic
   618 Simplifier setup for new object-logics;
   619 
   620 * Pure: AST translation rules no longer require constant head on LHS;
   621 
   622 * Pure: improved name spaces: ambiguous output is qualified; support
   623 for hiding of names;
   624 
   625 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   626 XSYMBOL_HOME; no longer need to do manual configuration in most
   627 situations;
   628 
   629 * system: compression of ML heaps images may now be controlled via -c
   630 option of isabelle and isatool usedir (currently only observed by
   631 Poly/ML);
   632 
   633 * system: isatool installfonts may handle X-Symbol fonts as well (very
   634 useful for remote X11);
   635 
   636 * system: provide TAGS file for Isabelle sources;
   637 
   638 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   639 order;
   640 
   641 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   642 timing flag supersedes proof_timing and Toplevel.trace;
   643 
   644 * ML: new combinators |>> and |>>> for incremental transformations
   645 with secondary results (e.g. certain theory extensions):
   646 
   647 * ML: PureThy.add_defs gets additional argument to indicate potential
   648 overloading (usually false);
   649 
   650 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   651 results;
   652 
   653 
   654 
   655 New in Isabelle99 (October 1999)
   656 --------------------------------
   657 
   658 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   659 
   660 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   661 are no longer simplified.  (This allows the simplifier to unfold recursive
   662 functional programs.)  To restore the old behaviour, declare
   663 
   664     Delcongs [if_weak_cong];
   665 
   666 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   667 complement;
   668 
   669 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   670 
   671 * HOL/datatype: mutual_induct_tac no longer exists --
   672   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   673 
   674 * HOL/typedef: fixed type inference for representing set; type
   675 arguments now have to occur explicitly on the rhs as type constraints;
   676 
   677 * ZF: The con_defs part of an inductive definition may no longer refer
   678 to constants declared in the same theory;
   679 
   680 * HOL, ZF: the function mk_cases, generated by the inductive
   681 definition package, has lost an argument.  To simplify its result, it
   682 uses the default simpset instead of a supplied list of theorems.
   683 
   684 * HOL/List: the constructors of type list are now Nil and Cons;
   685 
   686 * Simplifier: the type of the infix ML functions
   687         setSSolver addSSolver setSolver addSolver
   688 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   689 for packaging solvers. A solver is created via
   690         mk_solver: string -> (thm list -> int -> tactic) -> solver
   691 where the string argument is only a comment.
   692 
   693 
   694 *** Proof tools ***
   695 
   696 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   697 decision procedure for linear arithmetic. Currently it is used for
   698 types `nat', `int', and `real' in HOL (see below); it can, should and
   699 will be instantiated for other types and logics as well.
   700 
   701 * The simplifier now accepts rewrite rules with flexible heads, eg
   702      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   703   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   704   matching.
   705 
   706 
   707 *** General ***
   708 
   709 * New Isabelle/Isar subsystem provides an alternative to traditional
   710 tactical theorem proving; together with the ProofGeneral/isar user
   711 interface it offers an interactive environment for developing human
   712 readable proof documents (Isar == Intelligible semi-automated
   713 reasoning); for further information see isatool doc isar-ref,
   714 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   715 
   716 * improved and simplified presentation of theories: better HTML markup
   717 (including colors), graph views in several sizes; isatool usedir now
   718 provides a proper interface for user theories (via -P option); actual
   719 document preparation based on (PDF)LaTeX is available as well (for
   720 new-style theories only); see isatool doc system for more information;
   721 
   722 * native support for Proof General, both for classic Isabelle and
   723 Isabelle/Isar;
   724 
   725 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   726 using the graph browser tool;
   727 
   728 * Isabelle manuals now also available as PDF;
   729 
   730 * theory loader rewritten from scratch (may not be fully
   731 bug-compatible); old loadpath variable has been replaced by show_path,
   732 add_path, del_path, reset_path functions; new operations such as
   733 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   734 isatool doc ref);
   735 
   736 * improved isatool install: option -k creates KDE application icon,
   737 option -p DIR installs standalone binaries;
   738 
   739 * added ML_PLATFORM setting (useful for cross-platform installations);
   740 more robust handling of platform specific ML images for SML/NJ;
   741 
   742 * the settings environment is now statically scoped, i.e. it is never
   743 created again in sub-processes invoked from isabelle, isatool, or
   744 Isabelle;
   745 
   746 * path element specification '~~' refers to '$ISABELLE_HOME';
   747 
   748 * in locales, the "assumes" and "defines" parts may be omitted if
   749 empty;
   750 
   751 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   752 long arrows);
   753 
   754 * new print_mode "HTML";
   755 
   756 * new flag show_tags controls display of tags of theorems (which are
   757 basically just comments that may be attached by some tools);
   758 
   759 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   760 mode and goal output format:
   761 
   762 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   763 244c244
   764 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   765 ---
   766 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   767 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   768 181c181
   769 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   770 ---
   771 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   772 
   773 * function bind_thms stores lists of theorems (cf. bind_thm);
   774 
   775 * new shorthand tactics ftac, eatac, datac, fatac;
   776 
   777 * qed (and friends) now accept "" as result name; in that case the
   778 theorem is not stored, but proper checks and presentation of the
   779 result still apply;
   780 
   781 * theorem database now also indexes constants "Trueprop", "all",
   782 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   783 
   784 
   785 *** HOL ***
   786 
   787 ** HOL arithmetic **
   788 
   789 * There are now decision procedures for linear arithmetic over nat and
   790 int:
   791 
   792 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   793 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   794 are treated as atomic; subformulae not involving type `nat' or `int'
   795 are ignored; quantified subformulae are ignored unless they are
   796 positive universal or negative existential. The tactic has to be
   797 invoked by hand and can be a little bit slow. In particular, the
   798 running time is exponential in the number of occurrences of `min' and
   799 `max', and `-' on `nat'.
   800 
   801 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   802 (negated) (in)equalities among the premises and the conclusion into
   803 account (i.e. no compound formulae) and does not know about `min' and
   804 `max', and `-' on `nat'. It is fast and is used automatically by the
   805 simplifier.
   806 
   807 NB: At the moment, these decision procedures do not cope with mixed
   808 nat/int formulae where the two parts interact, such as `m < n ==>
   809 int(m) < int(n)'.
   810 
   811 * HOL/Numeral provides a generic theory of numerals (encoded
   812 efficiently as bit strings); setup for types nat/int/real is in place;
   813 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   814 int, existing theories and proof scripts may require a few additional
   815 type constraints;
   816 
   817 * integer division and remainder can now be performed on constant
   818 arguments;
   819 
   820 * many properties of integer multiplication, division and remainder
   821 are now available;
   822 
   823 * An interface to the Stanford Validity Checker (SVC) is available through the
   824 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   825 are proved automatically.  SVC must be installed separately, and its results
   826 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   827 invocation of the underlying oracle).  For SVC see
   828   http://verify.stanford.edu/SVC
   829 
   830 * IsaMakefile: the HOL-Real target now builds an actual image;
   831 
   832 
   833 ** HOL misc **
   834 
   835 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   836 (in Isabelle/Isar) -- by Gertrud Bauer;
   837 
   838 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   839 analysis for assembly languages with subtypes;
   840 
   841 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   842 -- avoids syntactic ambiguities and treats state, transition, and
   843 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   844 changed syntax and (many) tactics;
   845 
   846 * HOL/inductive: Now also handles more general introduction rules such
   847   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   848   theorems are now maintained within the theory (maintained via the
   849   "mono" attribute);
   850 
   851 * HOL/datatype: Now also handles arbitrarily branching datatypes
   852   (using function types) such as
   853 
   854   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   855 
   856 * HOL/record: record_simproc (part of the default simpset) takes care
   857 of selectors applied to updated records; record_split_tac is no longer
   858 part of the default claset; update_defs may now be removed from the
   859 simpset in many cases; COMPATIBILITY: old behavior achieved by
   860 
   861   claset_ref () := claset() addSWrapper record_split_wrapper;
   862   Delsimprocs [record_simproc]
   863 
   864 * HOL/typedef: fixed type inference for representing set; type
   865 arguments now have to occur explicitly on the rhs as type constraints;
   866 
   867 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   868 names rather than an ML expression;
   869 
   870 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   871 supplied later.  Program schemes can be defined, such as
   872     "While B C s = (if B s then While B C (C s) else s)"
   873 where the well-founded relation can be chosen after B and C have been given.
   874 
   875 * HOL/List: the constructors of type list are now Nil and Cons;
   876 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   877 course, ML tools referring to List.list.op # etc. have to be adapted;
   878 
   879 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   880 disabled by default; run isabelle with option -m HOL to get back to
   881 the original Gordon/HOL-style output;
   882 
   883 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   884 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   885 
   886 * HOL basic syntax simplified (more orthogonal): all variants of
   887 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   888 Eps operator is provided as well: "SOME x. P[x]";
   889 
   890 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   891 
   892 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   893 thus available for user theories;
   894 
   895 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   896 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   897 time;
   898 
   899 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   900 several times and then mp;
   901 
   902 
   903 *** LK ***
   904 
   905 * the notation <<...>> is now available as a notation for sequences of
   906 formulas;
   907 
   908 * the simplifier is now installed
   909 
   910 * the axiom system has been generalized (thanks to Soren Heilmann)
   911 
   912 * the classical reasoner now has a default rule database
   913 
   914 
   915 *** ZF ***
   916 
   917 * new primrec section allows primitive recursive functions to be given
   918 directly (as in HOL) over datatypes and the natural numbers;
   919 
   920 * new tactics induct_tac and exhaust_tac for induction (or case
   921 analysis) over datatypes and the natural numbers;
   922 
   923 * the datatype declaration of type T now defines the recursor T_rec;
   924 
   925 * simplification automatically does freeness reasoning for datatype
   926 constructors;
   927 
   928 * automatic type-inference, with AddTCs command to insert new
   929 type-checking rules;
   930 
   931 * datatype introduction rules are now added as Safe Introduction rules
   932 to the claset;
   933 
   934 * the syntax "if P then x else y" is now available in addition to
   935 if(P,x,y);
   936 
   937 
   938 *** Internal programming interfaces ***
   939 
   940 * tuned simplifier trace output; new flag debug_simp;
   941 
   942 * structures Vartab / Termtab (instances of TableFun) offer efficient
   943 tables indexed by indexname_ord / term_ord (compatible with aconv);
   944 
   945 * AxClass.axclass_tac lost the theory argument;
   946 
   947 * tuned current_goals_markers semantics: begin / end goal avoids
   948 printing empty lines;
   949 
   950 * removed prs and prs_fn hook, which was broken because it did not
   951 include \n in its semantics, forcing writeln to add one
   952 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   953 string -> unit if you really want to output text without newline;
   954 
   955 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   956 plain output, interface builders may have to enable 'isabelle_font'
   957 mode to get Isabelle font glyphs as before;
   958 
   959 * refined token_translation interface; INCOMPATIBILITY: output length
   960 now of type real instead of int;
   961 
   962 * theory loader actions may be traced via new ThyInfo.add_hook
   963 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   964 your own database of information attached to *whole* theories -- as
   965 opposed to intra-theory data slots offered via TheoryDataFun;
   966 
   967 * proper handling of dangling sort hypotheses (at last!);
   968 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   969 extra sort hypotheses that can be witnessed from the type signature;
   970 the force_strip_shyps flag is gone, any remaining shyps are simply
   971 left in the theorem (with a warning issued by strip_shyps_warning);
   972 
   973 
   974 
   975 New in Isabelle98-1 (October 1998)
   976 ----------------------------------
   977 
   978 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   979 
   980 * several changes of automated proof tools;
   981 
   982 * HOL: major changes to the inductive and datatype packages, including
   983 some minor incompatibilities of theory syntax;
   984 
   985 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   986 called `inj_on';
   987 
   988 * HOL: removed duplicate thms in Arith:
   989   less_imp_add_less  should be replaced by  trans_less_add1
   990   le_imp_add_le      should be replaced by  trans_le_add1
   991 
   992 * HOL: unary minus is now overloaded (new type constraints may be
   993 required);
   994 
   995 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   996 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   997 now taken as an integer constant.
   998 
   999 * Pure: ML function 'theory_of' renamed to 'theory';
  1000 
  1001 
  1002 *** Proof tools ***
  1003 
  1004 * Simplifier:
  1005   1. Asm_full_simp_tac is now more aggressive.
  1006      1. It will sometimes reorient premises if that increases their power to
  1007         simplify.
  1008      2. It does no longer proceed strictly from left to right but may also
  1009         rotate premises to achieve further simplification.
  1010      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1011      old Asm_full_simp_tac in that it does not rotate premises.
  1012   2. The simplifier now knows a little bit about nat-arithmetic.
  1013 
  1014 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1015 allows for selected deletion of wrappers, by introduction of names for
  1016 wrapper functionals.  This implies that addbefore, addSbefore,
  1017 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1018 and that adding two tactics with the same name overwrites the first
  1019 one (emitting a warning).
  1020   type wrapper = (int -> tactic) -> (int -> tactic)
  1021   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1022   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1023   delWrapper, delSWrapper: claset *  string            -> claset
  1024   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1025 
  1026 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1027 semantics; addbefore now affects only the unsafe part of step_tac
  1028 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1029 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1030 by Force_tac;
  1031 
  1032 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1033 compWrapper; added safe wrapper (and access functions for it);
  1034 
  1035 * HOL/split_all_tac is now much faster and fails if there is nothing
  1036 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1037 and the names of the automatically generated variables have changed.
  1038 split_all_tac has moved within claset() from unsafe wrappers to safe
  1039 wrappers, which means that !!-bound variables are split much more
  1040 aggressively, and safe_tac and clarify_tac now split such variables.
  1041 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1042 Note: the same holds for record_split_tac, which does the job of
  1043 split_all_tac for record fields.
  1044 
  1045 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1046 permanently to the default simpset using Addsplits just like
  1047 Addsimps. They can be removed via Delsplits just like
  1048 Delsimps. Lower-case versions are also available.
  1049 
  1050 * HOL/Simplifier: The rule split_if is now part of the default
  1051 simpset. This means that the simplifier will eliminate all occurrences
  1052 of if-then-else in the conclusion of a goal. To prevent this, you can
  1053 either remove split_if completely from the default simpset by
  1054 `Delsplits [split_if]' or remove it in a specific call of the
  1055 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1056 other case splitting rules to/from the default simpset: every datatype
  1057 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1058 t is the name of the datatype).
  1059 
  1060 * Classical reasoner / Simplifier combination: new force_tac (and
  1061 derivatives Force_tac, force) combines rewriting and classical
  1062 reasoning (and whatever other tools) similarly to auto_tac, but is
  1063 aimed to solve the given subgoal completely.
  1064 
  1065 
  1066 *** General ***
  1067 
  1068 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1069 and `goalw': the theory is no longer needed as an explicit argument -
  1070 the current theory context is used; assumptions are no longer returned
  1071 at the ML-level unless one of them starts with ==> or !!; it is
  1072 recommended to convert to these new commands using isatool fixgoal
  1073 (backup your sources first!);
  1074 
  1075 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1076 the current theory context, and 'theory' to lookup stored theories;
  1077 
  1078 * new theory section 'locale' for declaring constants, assumptions and
  1079 definitions that have local scope;
  1080 
  1081 * new theory section 'nonterminals' for purely syntactic types;
  1082 
  1083 * new theory section 'setup' for generic ML setup functions
  1084 (e.g. package initialization);
  1085 
  1086 * the distribution now includes Isabelle icons: see
  1087 lib/logo/isabelle-{small,tiny}.xpm;
  1088 
  1089 * isatool install - install binaries with absolute references to
  1090 ISABELLE_HOME/bin;
  1091 
  1092 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1093 
  1094 * print mode 'emacs' reserved for Isamode;
  1095 
  1096 * support multiple print (ast) translations per constant name;
  1097 
  1098 * theorems involving oracles are now printed with a suffixed [!];
  1099 
  1100 
  1101 *** HOL ***
  1102 
  1103 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1104 
  1105 * HOL/inductive package reorganized and improved: now supports mutual
  1106 definitions such as
  1107 
  1108   inductive EVEN ODD
  1109     intrs
  1110       null "0 : EVEN"
  1111       oddI "n : EVEN ==> Suc n : ODD"
  1112       evenI "n : ODD ==> Suc n : EVEN"
  1113 
  1114 new theorem list "elims" contains an elimination rule for each of the
  1115 recursive sets; inductive definitions now handle disjunctive premises
  1116 correctly (also ZF);
  1117 
  1118 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1119 "mutual_induct" no longer exists - the induction rule is always
  1120 contained in "induct";
  1121 
  1122 
  1123 * HOL/datatype package re-implemented and greatly improved: now
  1124 supports mutually recursive datatypes such as
  1125 
  1126   datatype
  1127     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1128             | SUM ('a aexp) ('a aexp)
  1129             | DIFF ('a aexp) ('a aexp)
  1130             | NUM 'a
  1131   and
  1132     'a bexp = LESS ('a aexp) ('a aexp)
  1133             | AND ('a bexp) ('a bexp)
  1134             | OR ('a bexp) ('a bexp)
  1135 
  1136 as well as indirectly recursive datatypes such as
  1137 
  1138   datatype
  1139     ('a, 'b) term = Var 'a
  1140                   | App 'b ((('a, 'b) term) list)
  1141 
  1142 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1143 induction on mutually / indirectly recursive datatypes.
  1144 
  1145 Primrec equations are now stored in theory and can be accessed via
  1146 <function_name>.simps.
  1147 
  1148 INCOMPATIBILITIES:
  1149 
  1150   - Theories using datatypes must now have theory Datatype as an
  1151     ancestor.
  1152   - The specific <typename>.induct_tac no longer exists - use the
  1153     generic induct_tac instead.
  1154   - natE has been renamed to nat.exhaust - use exhaust_tac
  1155     instead of res_inst_tac ... natE. Note that the variable
  1156     names in nat.exhaust differ from the names in natE, this
  1157     may cause some "fragile" proofs to fail.
  1158   - The theorems split_<typename>_case and split_<typename>_case_asm
  1159     have been renamed to <typename>.split and <typename>.split_asm.
  1160   - Since default sorts of type variables are now handled correctly,
  1161     some datatype definitions may have to be annotated with explicit
  1162     sort constraints.
  1163   - Primrec definitions no longer require function name and type
  1164     of recursive argument.
  1165 
  1166 Consider using isatool fixdatatype to adapt your theories and proof
  1167 scripts to the new package (backup your sources first!).
  1168 
  1169 
  1170 * HOL/record package: considerably improved implementation; now
  1171 includes concrete syntax for record types, terms, updates; theorems
  1172 for surjective pairing and splitting !!-bound record variables; proof
  1173 support is as follows:
  1174 
  1175   1) standard conversions (selectors or updates applied to record
  1176 constructor terms) are part of the standard simpset;
  1177 
  1178   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1179 made part of standard simpset and claset via addIffs;
  1180 
  1181   3) a tactic for record field splitting (record_split_tac) is part of
  1182 the standard claset (addSWrapper);
  1183 
  1184 To get a better idea about these rules you may retrieve them via
  1185 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1186 the name of your record type.
  1187 
  1188 The split tactic 3) conceptually simplifies by the following rule:
  1189 
  1190   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1191 
  1192 Thus any record variable that is bound by meta-all will automatically
  1193 blow up into some record constructor term, consequently the
  1194 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1195 solve record problems automatically.
  1196 
  1197 
  1198 * reorganized the main HOL image: HOL/Integ and String loaded by
  1199 default; theory Main includes everything;
  1200 
  1201 * automatic simplification of integer sums and comparisons, using cancellation;
  1202 
  1203 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1204 
  1205 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1206 
  1207 * many new identities for unions, intersections, set difference, etc.;
  1208 
  1209 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1210 called split_if, split_split, split_sum_case and split_nat_case (to go
  1211 with add/delsplits);
  1212 
  1213 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1214 (?x::unit) = (); this is made part of the default simpset, which COULD
  1215 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1216 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1217 unit_abs_eta_conv is added in order to counter the effect of
  1218 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1219 %u.f();
  1220 
  1221 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1222 makes more sense);
  1223 
  1224 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1225   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1226   disjointness reasoning but breaking a few old proofs.
  1227 
  1228 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1229 to 'converse' from 'inverse' (for compatibility with ZF and some
  1230 literature);
  1231 
  1232 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1233 the well-founded relation;
  1234 
  1235 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1236     Compl A.  The "Compl" syntax remains available as input syntax for this
  1237     release ONLY.
  1238 
  1239 * HOL/Update: new theory of function updates:
  1240     f(a:=b) == %x. if x=a then b else f x
  1241 may also be iterated as in f(a:=b,c:=d,...);
  1242 
  1243 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1244 
  1245 * HOL/List:
  1246   - new function list_update written xs[i:=v] that updates the i-th
  1247     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1248   - new function `upt' written [i..j(] which generates the list
  1249     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1250     bound write [i..j], which is a shorthand for [i..j+1(].
  1251   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1252 
  1253 * HOL/Arith:
  1254   - removed 'pred' (predecessor) function;
  1255   - generalized some theorems about n-1;
  1256   - many new laws about "div" and "mod";
  1257   - new laws about greatest common divisors (see theory ex/Primes);
  1258 
  1259 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1260 instead of "inverse";
  1261 
  1262 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1263   of the multiset ordering;
  1264 
  1265 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1266   (not included by default);
  1267 
  1268 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1269 
  1270 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1271   programs, i.e. different program variables may have different types.
  1272 
  1273 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1274   [previously, this check worked only if the rewrite rule was unconditional]
  1275   Now rew can involve either definitions or equalities (either == or =).
  1276 
  1277 
  1278 *** ZF ***
  1279 
  1280 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1281   only the theorems proved on ZF.ML;
  1282 
  1283 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1284   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1285   disjointness reasoning but breaking a few old proofs.
  1286 
  1287 * ZF/Update: new theory of function updates
  1288     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1289   may also be iterated as in f(a:=b,c:=d,...);
  1290 
  1291 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1292 
  1293 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1294   [previously, this check worked only if the rewrite rule was unconditional]
  1295   Now rew can involve either definitions or equalities (either == or =).
  1296 
  1297 * case_tac provided for compatibility with HOL
  1298     (like the old excluded_middle_tac, but with subgoals swapped)
  1299 
  1300 
  1301 *** Internal programming interfaces ***
  1302 
  1303 * Pure: several new basic modules made available for general use, see
  1304 also src/Pure/README;
  1305 
  1306 * improved the theory data mechanism to support encapsulation (data
  1307 kind name replaced by private Object.kind, acting as authorization
  1308 key); new type-safe user interface via functor TheoryDataFun; generic
  1309 print_data function becomes basically useless;
  1310 
  1311 * removed global_names compatibility flag -- all theory declarations
  1312 are qualified by default;
  1313 
  1314 * module Pure/Syntax now offers quote / antiquote translation
  1315 functions (useful for Hoare logic etc. with implicit dependencies);
  1316 see HOL/ex/Antiquote for an example use;
  1317 
  1318 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1319 cterm -> thm;
  1320 
  1321 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1322 subgoal;
  1323 
  1324 * Display.print_goals function moved to Locale.print_goals;
  1325 
  1326 * standard print function for goals supports current_goals_markers
  1327 variable for marking begin of proof, end of proof, start of goal; the
  1328 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1329 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1330 for example;
  1331 
  1332 
  1333 
  1334 New in Isabelle98 (January 1998)
  1335 --------------------------------
  1336 
  1337 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1338 
  1339 * changed lexical syntax of terms / types: dots made part of long
  1340 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1341 
  1342 * simpset (and claset) reference variable replaced by functions
  1343 simpset / simpset_ref;
  1344 
  1345 * no longer supports theory aliases (via merge) and non-trivial
  1346 implicit merge of thms' signatures;
  1347 
  1348 * most internal names of constants changed due to qualified names;
  1349 
  1350 * changed Pure/Sequence interface (see Pure/seq.ML);
  1351 
  1352 
  1353 *** General Changes ***
  1354 
  1355 * hierachically structured name spaces (for consts, types, axms, thms
  1356 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1357 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1358 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1359 long_names for fully qualified output names; NOTE: ML programs
  1360 (special tactics, packages etc.) referring to internal names may have
  1361 to be adapted to cope with fully qualified names; in case of severe
  1362 backward campatibility problems try setting 'global_names' at compile
  1363 time to have enrything declared within a flat name space; one may also
  1364 fine tune name declarations in theories via the 'global' and 'local'
  1365 section;
  1366 
  1367 * reimplemented the implicit simpset and claset using the new anytype
  1368 data filed in signatures; references simpset:simpset ref etc. are
  1369 replaced by functions simpset:unit->simpset and
  1370 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1371 to patch your ML files accordingly;
  1372 
  1373 * HTML output now includes theory graph data for display with Java
  1374 applet or isatool browser; data generated automatically via isatool
  1375 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1376 
  1377 * defs may now be conditional; improved rewrite_goals_tac to handle
  1378 conditional equations;
  1379 
  1380 * defs now admits additional type arguments, using TYPE('a) syntax;
  1381 
  1382 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1383 creates a new theory node; implicit merge of thms' signatures is
  1384 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1385 transfer:theory->thm->thm in (rare) cases;
  1386 
  1387 * improved handling of draft signatures / theories; draft thms (and
  1388 ctyps, cterms) are automatically promoted to real ones;
  1389 
  1390 * slightly changed interfaces for oracles: admit many per theory, named
  1391 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1392 
  1393 * print_goals: optional output of const types (set show_consts and
  1394 show_types);
  1395 
  1396 * improved output of warnings (###) and errors (***);
  1397 
  1398 * subgoal_tac displays a warning if the new subgoal has type variables;
  1399 
  1400 * removed old README and Makefiles;
  1401 
  1402 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1403 
  1404 * removed obsolete init_pps and init_database;
  1405 
  1406 * deleted the obsolete tactical STATE, which was declared by
  1407     fun STATE tacfun st = tacfun st st;
  1408 
  1409 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1410 (which abbreviates $HOME);
  1411 
  1412 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1413 use isatool fixseq to adapt your ML programs (this works for fully
  1414 qualified references to the Sequence structure only!);
  1415 
  1416 * use_thy no longer requires writable current directory; it always
  1417 reloads .ML *and* .thy file, if either one is out of date;
  1418 
  1419 
  1420 *** Classical Reasoner ***
  1421 
  1422 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1423 tactics that use classical reasoning to simplify a subgoal without
  1424 splitting it into several subgoals;
  1425 
  1426 * Safe_tac: like safe_tac but uses the default claset;
  1427 
  1428 
  1429 *** Simplifier ***
  1430 
  1431 * added simplification meta rules:
  1432     (asm_)(full_)simplify: simpset -> thm -> thm;
  1433 
  1434 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1435 logics (again);
  1436 
  1437 * added prems argument to simplification procedures;
  1438 
  1439 * HOL, FOL, ZF: added infix function `addsplits':
  1440   instead of `<simpset> setloop (split_tac <thms>)'
  1441   you can simply write `<simpset> addsplits <thms>'
  1442 
  1443 
  1444 *** Syntax ***
  1445 
  1446 * TYPE('a) syntax for type reflection terms;
  1447 
  1448 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1449 
  1450 * pretty printer: changed order of mixfix annotation preference (again!);
  1451 
  1452 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1453 
  1454 
  1455 *** HOL ***
  1456 
  1457 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1458   with `addloop' of the simplifier to faciliate case splitting in premises.
  1459 
  1460 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1461 
  1462 * HOL/Auth: new protocol proofs including some for the Internet
  1463   protocol TLS;
  1464 
  1465 * HOL/Map: new theory of `maps' a la VDM;
  1466 
  1467 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1468 cancelling out common nat summands from =, <, <= (in)equalities, or
  1469 differences; simplification procedures nat_cancel_factor for
  1470 cancelling common factor from =, <, <= (in)equalities over natural
  1471 sums; nat_cancel contains both kinds of procedures, it is installed by
  1472 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1473 
  1474 * HOL/simplifier: terms of the form
  1475   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1476   are rewritten to
  1477   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1478   and those of the form
  1479   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1480   are rewritten to
  1481   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1482 
  1483 * HOL/datatype
  1484   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1485 
  1486   P(t_case f1 ... fn x) =
  1487      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1488         ...
  1489        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1490      )
  1491 
  1492   and a theorem `split_t_case_asm' of the form
  1493 
  1494   P(t_case f1 ... fn x) =
  1495     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1496         ...
  1497        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1498      )
  1499   which can be added to a simpset via `addsplits'. The existing theorems
  1500   expand_list_case and expand_option_case have been renamed to
  1501   split_list_case and split_option_case.
  1502 
  1503 * HOL/Arithmetic:
  1504   - `pred n' is automatically converted to `n-1'.
  1505     Users are strongly encouraged not to use `pred' any longer,
  1506     because it will disappear altogether at some point.
  1507   - Users are strongly encouraged to write "0 < n" rather than
  1508     "n ~= 0". Theorems and proof tools have been modified towards this
  1509     `standard'.
  1510 
  1511 * HOL/Lists:
  1512   the function "set_of_list" has been renamed "set" (and its theorems too);
  1513   the function "nth" now takes its arguments in the reverse order and
  1514   has acquired the infix notation "!" as in "xs!n".
  1515 
  1516 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1517 
  1518 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1519   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1520 
  1521 * HOL/record: extensible records with schematic structural subtyping
  1522 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1523 still lacks various theorems and concrete record syntax;
  1524 
  1525 
  1526 *** HOLCF ***
  1527 
  1528 * removed "axioms" and "generated by" sections;
  1529 
  1530 * replaced "ops" section by extended "consts" section, which is capable of
  1531   handling the continuous function space "->" directly;
  1532 
  1533 * domain package:
  1534   . proves theorems immediately and stores them in the theory,
  1535   . creates hierachical name space,
  1536   . now uses normal mixfix annotations (instead of cinfix...),
  1537   . minor changes to some names and values (for consistency),
  1538   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1539   . separator between mutual domain defs: changed "," to "and",
  1540   . improved handling of sort constraints;  now they have to
  1541     appear on the left-hand side of the equations only;
  1542 
  1543 * fixed LAM <x,y,zs>.b syntax;
  1544 
  1545 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1546 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1547 
  1548 
  1549 *** FOL and ZF ***
  1550 
  1551 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1552   with `addloop' of the simplifier to faciliate case splitting in premises.
  1553 
  1554 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1555 in HOL, they strip ALL and --> from proved theorems;
  1556 
  1557 
  1558 
  1559 New in Isabelle94-8 (May 1997)
  1560 ------------------------------
  1561 
  1562 *** General Changes ***
  1563 
  1564 * new utilities to build / run / maintain Isabelle etc. (in parts
  1565 still somewhat experimental); old Makefiles etc. still functional;
  1566 
  1567 * new 'Isabelle System Manual';
  1568 
  1569 * INSTALL text, together with ./configure and ./build scripts;
  1570 
  1571 * reimplemented type inference for greater efficiency, better error
  1572 messages and clean internal interface;
  1573 
  1574 * prlim command for dealing with lots of subgoals (an easier way of
  1575 setting goals_limit);
  1576 
  1577 
  1578 *** Syntax ***
  1579 
  1580 * supports alternative (named) syntax tables (parser and pretty
  1581 printer); internal interface is provided by add_modesyntax(_i);
  1582 
  1583 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1584 be used in conjunction with the Isabelle symbol font; uses the
  1585 "symbols" syntax table;
  1586 
  1587 * added token_translation interface (may translate name tokens in
  1588 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1589 the current print_mode); IMPORTANT: user print translation functions
  1590 are responsible for marking newly introduced bounds
  1591 (Syntax.mark_boundT);
  1592 
  1593 * token translations for modes "xterm" and "xterm_color" that display
  1594 names in bold, underline etc. or colors (which requires a color
  1595 version of xterm);
  1596 
  1597 * infixes may now be declared with names independent of their syntax;
  1598 
  1599 * added typed_print_translation (like print_translation, but may
  1600 access type of constant);
  1601 
  1602 
  1603 *** Classical Reasoner ***
  1604 
  1605 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1606 some limitations.  Blast_tac...
  1607   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1608   + ignores elimination rules that don't have the correct format
  1609         (the conclusion MUST be a formula variable)
  1610   + ignores types, which can make HOL proofs fail
  1611   + rules must not require higher-order unification, e.g. apply_type in ZF
  1612     [message "Function Var's argument not a bound variable" relates to this]
  1613   + its proof strategy is more general but can actually be slower
  1614 
  1615 * substitution with equality assumptions no longer permutes other
  1616 assumptions;
  1617 
  1618 * minor changes in semantics of addafter (now called addaltern); renamed
  1619 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1620 (and access functions for it);
  1621 
  1622 * improved combination of classical reasoner and simplifier:
  1623   + functions for handling clasimpsets
  1624   + improvement of addss: now the simplifier is called _after_ the
  1625     safe steps.
  1626   + safe variant of addss called addSss: uses safe simplifications
  1627     _during_ the safe steps. It is more complete as it allows multiple
  1628     instantiations of unknowns (e.g. with slow_tac).
  1629 
  1630 *** Simplifier ***
  1631 
  1632 * added interface for simplification procedures (functions that
  1633 produce *proven* rewrite rules on the fly, depending on current
  1634 redex);
  1635 
  1636 * ordering on terms as parameter (used for ordered rewriting);
  1637 
  1638 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1639 
  1640 * the solver is now split into a safe and an unsafe part.
  1641 This should be invisible for the normal user, except that the
  1642 functions setsolver and addsolver have been renamed to setSolver and
  1643 addSolver; added safe_asm_full_simp_tac;
  1644 
  1645 
  1646 *** HOL ***
  1647 
  1648 * a generic induction tactic `induct_tac' which works for all datatypes and
  1649 also for type `nat';
  1650 
  1651 * a generic case distinction tactic `exhaust_tac' which works for all
  1652 datatypes and also for type `nat';
  1653 
  1654 * each datatype comes with a function `size';
  1655 
  1656 * patterns in case expressions allow tuple patterns as arguments to
  1657 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1658 
  1659 * primrec now also works with type nat;
  1660 
  1661 * recdef: a new declaration form, allows general recursive functions to be
  1662 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1663 
  1664 * the constant for negation has been renamed from "not" to "Not" to
  1665 harmonize with FOL, ZF, LK, etc.;
  1666 
  1667 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1668 infinite lists;
  1669 
  1670 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1671 
  1672 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1673 problems in commutative rings, using axiomatic type classes for + and *;
  1674 
  1675 * more examples in HOL/MiniML and HOL/Auth;
  1676 
  1677 * more default rewrite rules for quantifiers, union/intersection;
  1678 
  1679 * a new constant `arbitrary == @x.False';
  1680 
  1681 * HOLCF/IOA replaces old HOL/IOA;
  1682 
  1683 * HOLCF changes: derived all rules and arities
  1684   + axiomatic type classes instead of classes
  1685   + typedef instead of faking type definitions
  1686   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1687   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1688   + eliminated the types void, one, tr
  1689   + use unit lift and bool lift (with translations) instead of one and tr
  1690   + eliminated blift from Lift3.thy (use Def instead of blift)
  1691   all eliminated rules are derived as theorems --> no visible changes ;
  1692 
  1693 
  1694 *** ZF ***
  1695 
  1696 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1697 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1698 as ZF_cs addSIs [equalityI];
  1699 
  1700 
  1701 
  1702 New in Isabelle94-7 (November 96)
  1703 ---------------------------------
  1704 
  1705 * allowing negative levels (as offsets) in prlev and choplev;
  1706 
  1707 * super-linear speedup for large simplifications;
  1708 
  1709 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1710 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1711 FAIL); can suppress it using the command Delsimps (ex_simps @
  1712 all_simps); De Morgan laws are also now included, by default;
  1713 
  1714 * improved printing of ==>  :  ~:
  1715 
  1716 * new object-logic "Sequents" adds linear logic, while replacing LK
  1717 and Modal (thanks to Sara Kalvala);
  1718 
  1719 * HOL/Auth: correctness proofs for authentication protocols;
  1720 
  1721 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1722 examples on HOL/Auth);
  1723 
  1724 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1725 the rewriter and classical reasoner simultaneously;
  1726 
  1727 * function uresult no longer returns theorems in "standard" format;
  1728 regain previous version by: val uresult = standard o uresult;
  1729 
  1730 
  1731 
  1732 New in Isabelle94-6
  1733 -------------------
  1734 
  1735 * oracles -- these establish an interface between Isabelle and trusted
  1736 external reasoners, which may deliver results as theorems;
  1737 
  1738 * proof objects (in particular record all uses of oracles);
  1739 
  1740 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1741 
  1742 * "constdefs" section in theory files;
  1743 
  1744 * "primrec" section (HOL) no longer requires names;
  1745 
  1746 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1747 
  1748 
  1749 
  1750 New in Isabelle94-5
  1751 -------------------
  1752 
  1753 * reduced space requirements;
  1754 
  1755 * automatic HTML generation from theories;
  1756 
  1757 * theory files no longer require "..." (quotes) around most types;
  1758 
  1759 * new examples, including two proofs of the Church-Rosser theorem;
  1760 
  1761 * non-curried (1994) version of HOL is no longer distributed;
  1762 
  1763 
  1764 
  1765 New in Isabelle94-4
  1766 -------------------
  1767 
  1768 * greatly reduced space requirements;
  1769 
  1770 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1771 
  1772 * searchable theorem database (see the section "Retrieving theorems" on
  1773 page 8 of the Reference Manual);
  1774 
  1775 * new examples, including Grabczewski's monumental case study of the
  1776 Axiom of Choice;
  1777 
  1778 * The previous version of HOL renamed to Old_HOL;
  1779 
  1780 * The new version of HOL (previously called CHOL) uses a curried syntax
  1781 for functions.  Application looks like f a b instead of f(a,b);
  1782 
  1783 * Mutually recursive inductive definitions finally work in HOL;
  1784 
  1785 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1786 translates to the operator "split";
  1787 
  1788 
  1789 
  1790 New in Isabelle94-3
  1791 -------------------
  1792 
  1793 * new infix operator, addss, allowing the classical reasoner to
  1794 perform simplification at each step of its search.  Example:
  1795         fast_tac (cs addss ss)
  1796 
  1797 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1798 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1799 look like (a,b) instead of <a,b>;
  1800 
  1801 * PLEASE NOTE: CHOL will eventually replace HOL!
  1802 
  1803 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1804 It translates to the operator "split".  A new theory of integers is available;
  1805 
  1806 * In ZF, integer numerals now denote two's-complement binary integers.
  1807 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1808 
  1809 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1810 of the Axiom of Choice;
  1811 
  1812 
  1813 
  1814 New in Isabelle94-2
  1815 -------------------
  1816 
  1817 * Significantly faster resolution;
  1818 
  1819 * the different sections in a .thy file can now be mixed and repeated
  1820 freely;
  1821 
  1822 * Database of theorems for FOL, HOL and ZF.  New
  1823 commands including qed, qed_goal and bind_thm store theorems in the database.
  1824 
  1825 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1826 a given theory (thms_of), or find out what theory a theorem was proved in
  1827 (theory_of_thm);
  1828 
  1829 * Bugs fixed in the inductive definition and datatype packages;
  1830 
  1831 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1832 and HOL_dup_cs obsolete;
  1833 
  1834 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1835 have been removed;
  1836 
  1837 * Simpler definition of function space in ZF;
  1838 
  1839 * new results about cardinal and ordinal arithmetic in ZF;
  1840 
  1841 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1842 types;
  1843 
  1844 
  1845 $Id$