NEWS
author oheimb
Thu Feb 15 13:07:03 2001 +0100 (2001-02-15)
changeset 11130 d14fd58615b9
parent 11124 5b97a468b46d
child 11169 98c2f741e32b
permissions -rw-r--r--
added missiong word
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle99-2 (February 2001)
     6 -----------------------------------
     7 
     8 *** Overview of INCOMPATIBILITIES ***
     9 
    10 * HOL: inductive package no longer splits induction rule aggressively,
    11 but only as far as specified by the introductions given; the old
    12 format may be recovered via ML function complete_split_rule or attribute
    13 'split_rule (complete)';
    14 
    15 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
    16 gfp_Tarski to gfp_unfold;
    17 
    18 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
    19 
    20 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
    21 relation); infix "^^" has been renamed "``"; infix "``" has been
    22 renamed "`"; "univalent" has been renamed "single_valued";
    23 
    24 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
    25 operation;
    26 
    27 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
    28 
    29 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
    30 
    31 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
    32 consequence, it is no longer monotonic wrt. the local goal context
    33 (which is now passed through the inductive cases);
    34 
    35 * Document preparation: renamed standard symbols \<ll> to \<lless> and
    36 \<gg> to \<ggreater>;
    37 
    38 
    39 *** Document preparation ***
    40 
    41 * \isabellestyle{NAME} selects version of Isabelle output (currently
    42 available: are "it" for near math-mode best-style output, "sl" for
    43 slanted text style, and "tt" for plain type-writer; if no
    44 \isabellestyle command is given, output is according to slanted
    45 type-writer);
    46 
    47 * support sub/super scripts (for single symbols only), input syntax is
    48 like this: "A\<^sup>*" or "A\<^sup>\<star>";
    49 
    50 * some more standard symbols; see Appendix A of the system manual for
    51 the complete list of symbols defined in isabellesym.sty;
    52 
    53 * improved isabelle style files; more abstract symbol implementation
    54 (should now use \isamath{...} and \isatext{...} in custom symbol
    55 definitions);
    56 
    57 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
    58 state; Note that presentation of goal states does not conform to
    59 actual human-readable proof documents.  Please do not include goal
    60 states into document output unless you really know what you are doing!
    61 
    62 * proper indentation of antiquoted output with proportional LaTeX
    63 fonts;
    64 
    65 * no_document ML operator temporarily disables LaTeX document
    66 generation;
    67 
    68 * isatool unsymbolize tunes sources for plain ASCII communication;
    69 
    70 
    71 *** Isar ***
    72 
    73 * Pure: Isar now suffers initial goal statements to contain unbound
    74 schematic variables (this does not conform to actual readable proof
    75 documents, due to unpredictable outcome and non-compositional proof
    76 checking); users who know what they are doing may use schematic goals
    77 for Prolog-style synthesis of proven results;
    78 
    79 * Pure: assumption method (an implicit finishing) now handles actual
    80 rules as well;
    81 
    82 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
    83 initial goal, declare "that" only as Pure intro (only for single
    84 steps); the "that" rule assumption may now be involved in implicit
    85 finishing, thus ".." becomes a feasible for trivial obtains;
    86 
    87 * Pure: default proof step now includes 'intro_classes'; thus trivial
    88 instance proofs may be performed by "..";
    89 
    90 * Pure: ?thesis / ?this / "..." now work for pure meta-level
    91 statements as well;
    92 
    93 * Pure: more robust selection of calculational rules;
    94 
    95 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
    96 rule (as well as the assumption rule);
    97 
    98 * Pure: 'thm_deps' command visualizes dependencies of theorems and
    99 lemmas, using the graph browser tool;
   100 
   101 * Pure: predict failure of "show" in interactive mode;
   102 
   103 * Pure: 'thms_containing' now takes actual terms as arguments;
   104 
   105 * HOL: improved method 'induct' --- now handles non-atomic goals
   106 (potential INCOMPATIBILITY); tuned error handling;
   107 
   108 * HOL: cases and induct rules now provide explicit hints about the
   109 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   110 any remaining facts are inserted into the goal verbatim;
   111 
   112 * HOL: local contexts (aka cases) may now contain term bindings as
   113 well; the 'cases' and 'induct' methods new provide a ?case binding for
   114 the result to be shown in each case;
   115 
   116 * HOL: added 'recdef_tc' command;
   117 
   118 * isatool convert assists in eliminating legacy ML scripts;
   119 
   120 
   121 *** HOL ***
   122 
   123 * HOL/Library: a collection of generic theories to be used together
   124 with main HOL; the theory loader path already includes this directory
   125 by default; the following existing theories have been moved here:
   126 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   127 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   128 
   129 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   130 modelling and verification task performed in Isabelle/HOL +
   131 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   132 
   133 * HOL/Algebra: special summation operator SUM no longer exists, it has
   134 been replaced by setsum; infix 'assoc' now has priority 50 (like
   135 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   136 'domain', this makes the theory consistent with mathematical
   137 literature;
   138 
   139 * HOL basics: added overloaded operations "inverse" and "divide"
   140 (infix "/"), syntax for generic "abs" operation, generic summation
   141 operator \<Sum>;
   142 
   143 * HOL/typedef: simplified package, provide more useful rules (see also
   144 HOL/subset.thy);
   145 
   146 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   147 now expressed as a proper nested rule (old-style tactic scripts may
   148 require atomize_strip_tac to cope with non-atomic premises);
   149 
   150 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   151 to "split_conv" (old name still available for compatibility);
   152 
   153 * HOL: improved concrete syntax for strings (e.g. allows translation
   154 rules with string literals);
   155 
   156 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   157 and Fleuriot's mechanization of analysis;
   158 
   159 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   160 
   161 
   162 *** CTT ***
   163 
   164 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   165 "lam" is displayed as TWO lambda-symbols
   166 
   167 * CTT: theory Main now available, containing everything (that is, Bool
   168 and Arith);
   169 
   170 
   171 *** General ***
   172 
   173 * Pure: the Simplifier has been implemented properly as a derived rule
   174 outside of the actual kernel (at last!); the overall performance
   175 penalty in practical applications is about 50%, while reliability of
   176 the Isabelle inference kernel has been greatly improved;
   177 
   178 * print modes "brackets" and "no_brackets" control output of nested =>
   179 (types) and ==> (props); the default behaviour is "brackets";
   180 
   181 * Provers: fast_tac (and friends) now handle actual object-logic rules
   182 as assumptions as well;
   183 
   184 * system: support Poly/ML 4.0;
   185 
   186 * system: isatool install handles KDE version 1 or 2;
   187 
   188 
   189 
   190 New in Isabelle99-1 (October 2000)
   191 ----------------------------------
   192 
   193 *** Overview of INCOMPATIBILITIES ***
   194 
   195 * HOL: simplification of natural numbers is much changed; to partly
   196 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   197 issue the following ML commands:
   198 
   199   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   200   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   201 
   202 * HOL: simplification no longer dives into case-expressions; this is
   203 controlled by "t.weak_case_cong" for each datatype t;
   204 
   205 * HOL: nat_less_induct renamed to less_induct;
   206 
   207 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   208 fixsome to patch .thy and .ML sources automatically;
   209 
   210   select_equality  -> some_equality
   211   select_eq_Ex     -> some_eq_ex
   212   selectI2EX       -> someI2_ex
   213   selectI2         -> someI2
   214   selectI          -> someI
   215   select1_equality -> some1_equality
   216   Eps_sym_eq       -> some_sym_eq_trivial
   217   Eps_eq           -> some_eq_trivial
   218 
   219 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   220 
   221 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   222 instead);
   223 
   224 * HOL: the recursion equations generated by 'recdef' are now called
   225 f.simps instead of f.rules;
   226 
   227 * HOL: qed_spec_mp now also handles bounded ALL as well;
   228 
   229 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   230 sometimes be needed;
   231 
   232 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   233 
   234 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   235 
   236 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   237 product is now "<*>" instead of "Times"; the lexicographic product is
   238 now "<*lex*>" instead of "**";
   239 
   240 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   241 of main HOL, but was unused); better use HOL's datatype package;
   242 
   243 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   244 the old syntax may be recovered as follows:
   245 
   246   syntax (symbols)
   247     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   248       (infixl "\\<oplus>" 100)
   249 
   250 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   251 
   252 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   253 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   254 internally;
   255 
   256 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   257 changed from A/r to A//r;
   258 
   259 * ZF: new treatment of arithmetic (nat & int) may break some old
   260 proofs;
   261 
   262 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   263 rulify -> rule_format, elimify -> elim_format, ...);
   264 
   265 * Isar/Provers: intro/elim/dest attributes changed; renamed
   266 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   267 should have to change intro!! to intro? only); replaced "delrule" by
   268 "rule del";
   269 
   270 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   271 
   272 * Provers: strengthened force_tac by using new first_best_tac;
   273 
   274 * LaTeX document preparation: several changes of isabelle.sty (see
   275 lib/texinputs);
   276 
   277 
   278 *** Document preparation ***
   279 
   280 * formal comments (text blocks etc.) in new-style theories may now
   281 contain antiquotations of thm/prop/term/typ/text to be presented
   282 according to latex print mode; concrete syntax is like this:
   283 @{term[show_types] "f(x) = a + x"};
   284 
   285 * isatool mkdir provides easy setup of Isabelle session directories,
   286 including proper document sources;
   287 
   288 * generated LaTeX sources are now deleted after successful run
   289 (isatool document -c); may retain a copy somewhere else via -D option
   290 of isatool usedir;
   291 
   292 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   293 style files, achieving self-contained LaTeX sources and simplifying
   294 LaTeX debugging;
   295 
   296 * old-style theories now produce (crude) LaTeX output as well;
   297 
   298 * browser info session directories are now self-contained (may be put
   299 on WWW server seperately); improved graphs of nested sessions; removed
   300 graph for 'all sessions';
   301 
   302 * several improvements in isabelle style files; \isabellestyle{it}
   303 produces fake math mode output; \isamarkupheader is now \section by
   304 default; see lib/texinputs/isabelle.sty etc.;
   305 
   306 
   307 *** Isar ***
   308 
   309 * Isar/Pure: local results and corresponding term bindings are now
   310 subject to Hindley-Milner polymorphism (similar to ML); this
   311 accommodates incremental type-inference very nicely;
   312 
   313 * Isar/Pure: new derived language element 'obtain' supports
   314 generalized existence reasoning;
   315 
   316 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   317 support accumulation of results, without applying any rules yet;
   318 useful to collect intermediate results without explicit name
   319 references, and for use with transitivity rules with more than 2
   320 premises;
   321 
   322 * Isar/Pure: scalable support for case-analysis type proofs: new
   323 'case' language element refers to local contexts symbolically, as
   324 produced by certain proof methods; internally, case names are attached
   325 to theorems as "tags";
   326 
   327 * Isar/Pure: theory command 'hide' removes declarations from
   328 class/type/const name spaces;
   329 
   330 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   331 indicate potential overloading;
   332 
   333 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   334 
   335 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   336 "{a,b,c}" instead of {a,b,c};
   337 
   338 * Isar/Pure now provides its own version of intro/elim/dest
   339 attributes; useful for building new logics, but beware of confusion
   340 with the version in Provers/classical;
   341 
   342 * Isar/Pure: the local context of (non-atomic) goals is provided via
   343 case name 'antecedent';
   344 
   345 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   346 to the current context is now done automatically);
   347 
   348 * Isar/Pure: theory command 'method_setup' provides a simple interface
   349 for definining proof methods in ML;
   350 
   351 * Isar/Provers: intro/elim/dest attributes changed; renamed
   352 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   353 most cases, one should have to change intro!! to intro? only);
   354 replaced "delrule" by "rule del";
   355 
   356 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   357 'symmetric' attribute (the latter supercedes [RS sym]);
   358 
   359 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   360 method modifier); 'simp' method: 'only:' modifier removes loopers as
   361 well (including splits);
   362 
   363 * Isar/Provers: Simplifier and Classical methods now support all kind
   364 of modifiers used in the past, including 'cong', 'iff', etc.
   365 
   366 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   367 of Simplifier and Classical reasoner);
   368 
   369 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   370 now support named cases; major packages (inductive, datatype, primrec,
   371 recdef) support case names and properly name parameters;
   372 
   373 * Isar/HOL: new transitivity rules for substitution in inequalities --
   374 monotonicity conditions are extracted to be proven at end of
   375 calculations;
   376 
   377 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   378 method anyway;
   379 
   380 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   381 split_if split_if_asm; datatype package provides theorems foo.splits =
   382 foo.split foo.split_asm for each datatype;
   383 
   384 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   385 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   386 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   387 use "(cases (simplified))" method in proper proof texts);
   388 
   389 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   390 
   391 * Isar: names of theorems etc. may be natural numbers as well;
   392 
   393 * Isar: 'pr' command: optional arguments for goals_limit and
   394 ProofContext.prems_limit; no longer prints theory contexts, but only
   395 proof states;
   396 
   397 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   398 additional print modes to be specified; e.g. "pr(latex)" will print
   399 proof state according to the Isabelle LaTeX style;
   400 
   401 * Isar: improved support for emulating tactic scripts, including proof
   402 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   403 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   404 (for HOL datatypes);
   405 
   406 * Isar: simplified (more robust) goal selection of proof methods: 1st
   407 goal, all goals, or explicit goal specifier (tactic emulation); thus
   408 'proof method scripts' have to be in depth-first order;
   409 
   410 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   411 
   412 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   413 should instead use individual commands for printing items
   414 (print_commands, print_methods etc.);
   415 
   416 * Isar: added 'nothing' --- the empty list of theorems;
   417 
   418 
   419 *** HOL ***
   420 
   421 * HOL/MicroJava: formalization of a fragment of Java, together with a
   422 corresponding virtual machine and a specification of its bytecode
   423 verifier and a lightweight bytecode verifier, including proofs of
   424 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   425 Cornelia Pusch (see also the homepage of project Bali at
   426 http://isabelle.in.tum.de/Bali/);
   427 
   428 * HOL/Algebra: new theory of rings and univariate polynomials, by
   429 Clemens Ballarin;
   430 
   431 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   432 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   433 Rasmussen;
   434 
   435 * HOL/Lattice: fundamental concepts of lattice theory and order
   436 structures, including duals, properties of bounds versus algebraic
   437 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   438 Theorem for complete lattices etc.; may also serve as a demonstration
   439 for abstract algebraic reasoning using axiomatic type classes, and
   440 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   441 
   442 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   443 von Oheimb;
   444 
   445 * HOL/IMPP: extension of IMP with local variables and mutually
   446 recursive procedures, by David von Oheimb;
   447 
   448 * HOL/Lambda: converted into new-style theory and document;
   449 
   450 * HOL/ex/Multiquote: example of multiple nested quotations and
   451 anti-quotations -- basically a generalized version of de-Bruijn
   452 representation; very useful in avoiding lifting of operations;
   453 
   454 * HOL/record: added general record equality rule to simpset; fixed
   455 select-update simplification procedure to handle extended records as
   456 well; admit "r" as field name;
   457 
   458 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   459 other numeric types and also as the identity of groups, rings, etc.;
   460 
   461 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   462 Types nat and int belong to this axclass;
   463 
   464 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   465    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   466    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   467   two terms #m*u and #n*u are replaced by #(m+n)*u
   468     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   469   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   470     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   471 
   472 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   473 powerful prover for predicate logic but knows nothing of clasets; see
   474 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   475 
   476 * HOL: new version of "case_tac" subsumes both boolean case split and
   477 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   478 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   479 
   480 * HOL: simplification no longer dives into case-expressions: only the
   481 selector expression is simplified, but not the remaining arms; to
   482 enable full simplification of case-expressions for datatype t, you may
   483 remove t.weak_case_cong from the simpset, either globally (Delcongs
   484 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   485 
   486 * HOL/recdef: the recursion equations generated by 'recdef' for
   487 function 'f' are now called f.simps instead of f.rules; if all
   488 termination conditions are proved automatically, these simplification
   489 rules are added to the simpset, as in primrec; rules may be named
   490 individually as well, resulting in a separate list of theorems for
   491 each equation;
   492 
   493 * HOL/While is a new theory that provides a while-combinator. It
   494 permits the definition of tail-recursive functions without the
   495 provision of a termination measure. The latter is necessary once the
   496 invariant proof rule for while is applied.
   497 
   498 * HOL: new (overloaded) notation for the set of elements below/above
   499 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   500 
   501 * HOL: theorems impI, allI, ballI bound as "strip";
   502 
   503 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   504 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   505 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   506 
   507 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   508 
   509 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   510 main HOL, but was unused);
   511 
   512 * HOL: fewer consts declared as global (e.g. have to refer to
   513 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   514 
   515 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   516 in case of overlap with user translations (e.g. judgements over
   517 tuples); (note that the underlying logical represenation is still
   518 bogus);
   519 
   520 
   521 *** ZF ***
   522 
   523 * ZF: simplification automatically cancels common terms in arithmetic
   524 expressions over nat and int;
   525 
   526 * ZF: new treatment of nat to minimize type-checking: all operators
   527 coerce their operands to a natural number using the function natify,
   528 making the algebraic laws unconditional;
   529 
   530 * ZF: as above, for int: operators coerce their operands to an integer
   531 using the function intify;
   532 
   533 * ZF: the integer library now contains many of the usual laws for the
   534 orderings, including $<=, and monotonicity laws for $+ and $*;
   535 
   536 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   537 simplification;
   538 
   539 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   540 to the simplifier and classical reasoner simultaneously;
   541 
   542 
   543 *** General ***
   544 
   545 * Provers: blast_tac now handles actual object-logic rules as
   546 assumptions; note that auto_tac uses blast_tac internally as well;
   547 
   548 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   549 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   550 
   551 * Provers: delrules now handles destruct rules as well (no longer need
   552 explicit make_elim);
   553 
   554 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   555   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   556 use instead the strong form,
   557   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   558 in HOL, FOL and ZF the function cla_make_elim will create such rules
   559 from destruct-rules;
   560 
   561 * Provers: Simplifier.easy_setup provides a fast path to basic
   562 Simplifier setup for new object-logics;
   563 
   564 * Pure: AST translation rules no longer require constant head on LHS;
   565 
   566 * Pure: improved name spaces: ambiguous output is qualified; support
   567 for hiding of names;
   568 
   569 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   570 XSYMBOL_HOME; no longer need to do manual configuration in most
   571 situations;
   572 
   573 * system: compression of ML heaps images may now be controlled via -c
   574 option of isabelle and isatool usedir (currently only observed by
   575 Poly/ML);
   576 
   577 * system: isatool installfonts may handle X-Symbol fonts as well (very
   578 useful for remote X11);
   579 
   580 * system: provide TAGS file for Isabelle sources;
   581 
   582 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   583 order;
   584 
   585 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   586 timing flag supersedes proof_timing and Toplevel.trace;
   587 
   588 * ML: new combinators |>> and |>>> for incremental transformations
   589 with secondary results (e.g. certain theory extensions):
   590 
   591 * ML: PureThy.add_defs gets additional argument to indicate potential
   592 overloading (usually false);
   593 
   594 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   595 results;
   596 
   597 
   598 
   599 New in Isabelle99 (October 1999)
   600 --------------------------------
   601 
   602 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   603 
   604 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   605 are no longer simplified.  (This allows the simplifier to unfold recursive
   606 functional programs.)  To restore the old behaviour, declare
   607 
   608     Delcongs [if_weak_cong];
   609 
   610 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   611 complement;
   612 
   613 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   614 
   615 * HOL/datatype: mutual_induct_tac no longer exists --
   616   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   617 
   618 * HOL/typedef: fixed type inference for representing set; type
   619 arguments now have to occur explicitly on the rhs as type constraints;
   620 
   621 * ZF: The con_defs part of an inductive definition may no longer refer
   622 to constants declared in the same theory;
   623 
   624 * HOL, ZF: the function mk_cases, generated by the inductive
   625 definition package, has lost an argument.  To simplify its result, it
   626 uses the default simpset instead of a supplied list of theorems.
   627 
   628 * HOL/List: the constructors of type list are now Nil and Cons;
   629 
   630 * Simplifier: the type of the infix ML functions
   631         setSSolver addSSolver setSolver addSolver
   632 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   633 for packaging solvers. A solver is created via
   634         mk_solver: string -> (thm list -> int -> tactic) -> solver
   635 where the string argument is only a comment.
   636 
   637 
   638 *** Proof tools ***
   639 
   640 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   641 decision procedure for linear arithmetic. Currently it is used for
   642 types `nat', `int', and `real' in HOL (see below); it can, should and
   643 will be instantiated for other types and logics as well.
   644 
   645 * The simplifier now accepts rewrite rules with flexible heads, eg
   646      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   647   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   648   matching.
   649 
   650 
   651 *** General ***
   652 
   653 * New Isabelle/Isar subsystem provides an alternative to traditional
   654 tactical theorem proving; together with the ProofGeneral/isar user
   655 interface it offers an interactive environment for developing human
   656 readable proof documents (Isar == Intelligible semi-automated
   657 reasoning); for further information see isatool doc isar-ref,
   658 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   659 
   660 * improved and simplified presentation of theories: better HTML markup
   661 (including colors), graph views in several sizes; isatool usedir now
   662 provides a proper interface for user theories (via -P option); actual
   663 document preparation based on (PDF)LaTeX is available as well (for
   664 new-style theories only); see isatool doc system for more information;
   665 
   666 * native support for Proof General, both for classic Isabelle and
   667 Isabelle/Isar;
   668 
   669 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   670 using the graph browser tool;
   671 
   672 * Isabelle manuals now also available as PDF;
   673 
   674 * theory loader rewritten from scratch (may not be fully
   675 bug-compatible); old loadpath variable has been replaced by show_path,
   676 add_path, del_path, reset_path functions; new operations such as
   677 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   678 isatool doc ref);
   679 
   680 * improved isatool install: option -k creates KDE application icon,
   681 option -p DIR installs standalone binaries;
   682 
   683 * added ML_PLATFORM setting (useful for cross-platform installations);
   684 more robust handling of platform specific ML images for SML/NJ;
   685 
   686 * the settings environment is now statically scoped, i.e. it is never
   687 created again in sub-processes invoked from isabelle, isatool, or
   688 Isabelle;
   689 
   690 * path element specification '~~' refers to '$ISABELLE_HOME';
   691 
   692 * in locales, the "assumes" and "defines" parts may be omitted if
   693 empty;
   694 
   695 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   696 long arrows);
   697 
   698 * new print_mode "HTML";
   699 
   700 * new flag show_tags controls display of tags of theorems (which are
   701 basically just comments that may be attached by some tools);
   702 
   703 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   704 mode and goal output format:
   705 
   706 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   707 244c244
   708 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   709 ---
   710 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   711 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   712 181c181
   713 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   714 ---
   715 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   716 
   717 * function bind_thms stores lists of theorems (cf. bind_thm);
   718 
   719 * new shorthand tactics ftac, eatac, datac, fatac;
   720 
   721 * qed (and friends) now accept "" as result name; in that case the
   722 theorem is not stored, but proper checks and presentation of the
   723 result still apply;
   724 
   725 * theorem database now also indexes constants "Trueprop", "all",
   726 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   727 
   728 
   729 *** HOL ***
   730 
   731 ** HOL arithmetic **
   732 
   733 * There are now decision procedures for linear arithmetic over nat and
   734 int:
   735 
   736 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   737 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   738 are treated as atomic; subformulae not involving type `nat' or `int'
   739 are ignored; quantified subformulae are ignored unless they are
   740 positive universal or negative existential. The tactic has to be
   741 invoked by hand and can be a little bit slow. In particular, the
   742 running time is exponential in the number of occurrences of `min' and
   743 `max', and `-' on `nat'.
   744 
   745 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   746 (negated) (in)equalities among the premises and the conclusion into
   747 account (i.e. no compound formulae) and does not know about `min' and
   748 `max', and `-' on `nat'. It is fast and is used automatically by the
   749 simplifier.
   750 
   751 NB: At the moment, these decision procedures do not cope with mixed
   752 nat/int formulae where the two parts interact, such as `m < n ==>
   753 int(m) < int(n)'.
   754 
   755 * HOL/Numeral provides a generic theory of numerals (encoded
   756 efficiently as bit strings); setup for types nat/int/real is in place;
   757 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   758 int, existing theories and proof scripts may require a few additional
   759 type constraints;
   760 
   761 * integer division and remainder can now be performed on constant
   762 arguments;
   763 
   764 * many properties of integer multiplication, division and remainder
   765 are now available;
   766 
   767 * An interface to the Stanford Validity Checker (SVC) is available through the
   768 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   769 are proved automatically.  SVC must be installed separately, and its results
   770 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   771 invocation of the underlying oracle).  For SVC see
   772   http://verify.stanford.edu/SVC
   773 
   774 * IsaMakefile: the HOL-Real target now builds an actual image;
   775 
   776 
   777 ** HOL misc **
   778 
   779 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   780 (in Isabelle/Isar) -- by Gertrud Bauer;
   781 
   782 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   783 analysis for assembly languages with subtypes;
   784 
   785 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   786 -- avoids syntactic ambiguities and treats state, transition, and
   787 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   788 changed syntax and (many) tactics;
   789 
   790 * HOL/inductive: Now also handles more general introduction rules such
   791   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   792   theorems are now maintained within the theory (maintained via the
   793   "mono" attribute);
   794 
   795 * HOL/datatype: Now also handles arbitrarily branching datatypes
   796   (using function types) such as
   797 
   798   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   799 
   800 * HOL/record: record_simproc (part of the default simpset) takes care
   801 of selectors applied to updated records; record_split_tac is no longer
   802 part of the default claset; update_defs may now be removed from the
   803 simpset in many cases; COMPATIBILITY: old behavior achieved by
   804 
   805   claset_ref () := claset() addSWrapper record_split_wrapper;
   806   Delsimprocs [record_simproc]
   807 
   808 * HOL/typedef: fixed type inference for representing set; type
   809 arguments now have to occur explicitly on the rhs as type constraints;
   810 
   811 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   812 names rather than an ML expression;
   813 
   814 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   815 supplied later.  Program schemes can be defined, such as
   816     "While B C s = (if B s then While B C (C s) else s)"
   817 where the well-founded relation can be chosen after B and C have been given.
   818 
   819 * HOL/List: the constructors of type list are now Nil and Cons;
   820 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   821 course, ML tools referring to List.list.op # etc. have to be adapted;
   822 
   823 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   824 disabled by default; run isabelle with option -m HOL to get back to
   825 the original Gordon/HOL-style output;
   826 
   827 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   828 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   829 
   830 * HOL basic syntax simplified (more orthogonal): all variants of
   831 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   832 Eps operator is provided as well: "SOME x. P[x]";
   833 
   834 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   835 
   836 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   837 thus available for user theories;
   838 
   839 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   840 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   841 time;
   842 
   843 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   844 several times and then mp;
   845 
   846 
   847 *** LK ***
   848 
   849 * the notation <<...>> is now available as a notation for sequences of
   850 formulas;
   851 
   852 * the simplifier is now installed
   853 
   854 * the axiom system has been generalized (thanks to Soren Heilmann)
   855 
   856 * the classical reasoner now has a default rule database
   857 
   858 
   859 *** ZF ***
   860 
   861 * new primrec section allows primitive recursive functions to be given
   862 directly (as in HOL) over datatypes and the natural numbers;
   863 
   864 * new tactics induct_tac and exhaust_tac for induction (or case
   865 analysis) over datatypes and the natural numbers;
   866 
   867 * the datatype declaration of type T now defines the recursor T_rec;
   868 
   869 * simplification automatically does freeness reasoning for datatype
   870 constructors;
   871 
   872 * automatic type-inference, with AddTCs command to insert new
   873 type-checking rules;
   874 
   875 * datatype introduction rules are now added as Safe Introduction rules
   876 to the claset;
   877 
   878 * the syntax "if P then x else y" is now available in addition to
   879 if(P,x,y);
   880 
   881 
   882 *** Internal programming interfaces ***
   883 
   884 * tuned simplifier trace output; new flag debug_simp;
   885 
   886 * structures Vartab / Termtab (instances of TableFun) offer efficient
   887 tables indexed by indexname_ord / term_ord (compatible with aconv);
   888 
   889 * AxClass.axclass_tac lost the theory argument;
   890 
   891 * tuned current_goals_markers semantics: begin / end goal avoids
   892 printing empty lines;
   893 
   894 * removed prs and prs_fn hook, which was broken because it did not
   895 include \n in its semantics, forcing writeln to add one
   896 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   897 string -> unit if you really want to output text without newline;
   898 
   899 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   900 plain output, interface builders may have to enable 'isabelle_font'
   901 mode to get Isabelle font glyphs as before;
   902 
   903 * refined token_translation interface; INCOMPATIBILITY: output length
   904 now of type real instead of int;
   905 
   906 * theory loader actions may be traced via new ThyInfo.add_hook
   907 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   908 your own database of information attached to *whole* theories -- as
   909 opposed to intra-theory data slots offered via TheoryDataFun;
   910 
   911 * proper handling of dangling sort hypotheses (at last!);
   912 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   913 extra sort hypotheses that can be witnessed from the type signature;
   914 the force_strip_shyps flag is gone, any remaining shyps are simply
   915 left in the theorem (with a warning issued by strip_shyps_warning);
   916 
   917 
   918 
   919 New in Isabelle98-1 (October 1998)
   920 ----------------------------------
   921 
   922 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   923 
   924 * several changes of automated proof tools;
   925 
   926 * HOL: major changes to the inductive and datatype packages, including
   927 some minor incompatibilities of theory syntax;
   928 
   929 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   930 called `inj_on';
   931 
   932 * HOL: removed duplicate thms in Arith:
   933   less_imp_add_less  should be replaced by  trans_less_add1
   934   le_imp_add_le      should be replaced by  trans_le_add1
   935 
   936 * HOL: unary minus is now overloaded (new type constraints may be
   937 required);
   938 
   939 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   940 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   941 now taken as an integer constant.
   942 
   943 * Pure: ML function 'theory_of' renamed to 'theory';
   944 
   945 
   946 *** Proof tools ***
   947 
   948 * Simplifier:
   949   1. Asm_full_simp_tac is now more aggressive.
   950      1. It will sometimes reorient premises if that increases their power to
   951         simplify.
   952      2. It does no longer proceed strictly from left to right but may also
   953         rotate premises to achieve further simplification.
   954      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   955      old Asm_full_simp_tac in that it does not rotate premises.
   956   2. The simplifier now knows a little bit about nat-arithmetic.
   957 
   958 * Classical reasoner: wrapper mechanism for the classical reasoner now
   959 allows for selected deletion of wrappers, by introduction of names for
   960 wrapper functionals.  This implies that addbefore, addSbefore,
   961 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   962 and that adding two tactics with the same name overwrites the first
   963 one (emitting a warning).
   964   type wrapper = (int -> tactic) -> (int -> tactic)
   965   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   966   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   967   delWrapper, delSWrapper: claset *  string            -> claset
   968   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   969 
   970 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   971 semantics; addbefore now affects only the unsafe part of step_tac
   972 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   973 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   974 by Force_tac;
   975 
   976 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   977 compWrapper; added safe wrapper (and access functions for it);
   978 
   979 * HOL/split_all_tac is now much faster and fails if there is nothing
   980 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   981 and the names of the automatically generated variables have changed.
   982 split_all_tac has moved within claset() from unsafe wrappers to safe
   983 wrappers, which means that !!-bound variables are split much more
   984 aggressively, and safe_tac and clarify_tac now split such variables.
   985 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   986 Note: the same holds for record_split_tac, which does the job of
   987 split_all_tac for record fields.
   988 
   989 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   990 permanently to the default simpset using Addsplits just like
   991 Addsimps. They can be removed via Delsplits just like
   992 Delsimps. Lower-case versions are also available.
   993 
   994 * HOL/Simplifier: The rule split_if is now part of the default
   995 simpset. This means that the simplifier will eliminate all occurrences
   996 of if-then-else in the conclusion of a goal. To prevent this, you can
   997 either remove split_if completely from the default simpset by
   998 `Delsplits [split_if]' or remove it in a specific call of the
   999 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1000 other case splitting rules to/from the default simpset: every datatype
  1001 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1002 t is the name of the datatype).
  1003 
  1004 * Classical reasoner / Simplifier combination: new force_tac (and
  1005 derivatives Force_tac, force) combines rewriting and classical
  1006 reasoning (and whatever other tools) similarly to auto_tac, but is
  1007 aimed to solve the given subgoal completely.
  1008 
  1009 
  1010 *** General ***
  1011 
  1012 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1013 and `goalw': the theory is no longer needed as an explicit argument -
  1014 the current theory context is used; assumptions are no longer returned
  1015 at the ML-level unless one of them starts with ==> or !!; it is
  1016 recommended to convert to these new commands using isatool fixgoal
  1017 (backup your sources first!);
  1018 
  1019 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1020 the current theory context, and 'theory' to lookup stored theories;
  1021 
  1022 * new theory section 'locale' for declaring constants, assumptions and
  1023 definitions that have local scope;
  1024 
  1025 * new theory section 'nonterminals' for purely syntactic types;
  1026 
  1027 * new theory section 'setup' for generic ML setup functions
  1028 (e.g. package initialization);
  1029 
  1030 * the distribution now includes Isabelle icons: see
  1031 lib/logo/isabelle-{small,tiny}.xpm;
  1032 
  1033 * isatool install - install binaries with absolute references to
  1034 ISABELLE_HOME/bin;
  1035 
  1036 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1037 
  1038 * print mode 'emacs' reserved for Isamode;
  1039 
  1040 * support multiple print (ast) translations per constant name;
  1041 
  1042 * theorems involving oracles are now printed with a suffixed [!];
  1043 
  1044 
  1045 *** HOL ***
  1046 
  1047 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1048 
  1049 * HOL/inductive package reorganized and improved: now supports mutual
  1050 definitions such as
  1051 
  1052   inductive EVEN ODD
  1053     intrs
  1054       null "0 : EVEN"
  1055       oddI "n : EVEN ==> Suc n : ODD"
  1056       evenI "n : ODD ==> Suc n : EVEN"
  1057 
  1058 new theorem list "elims" contains an elimination rule for each of the
  1059 recursive sets; inductive definitions now handle disjunctive premises
  1060 correctly (also ZF);
  1061 
  1062 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1063 "mutual_induct" no longer exists - the induction rule is always
  1064 contained in "induct";
  1065 
  1066 
  1067 * HOL/datatype package re-implemented and greatly improved: now
  1068 supports mutually recursive datatypes such as
  1069 
  1070   datatype
  1071     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1072             | SUM ('a aexp) ('a aexp)
  1073             | DIFF ('a aexp) ('a aexp)
  1074             | NUM 'a
  1075   and
  1076     'a bexp = LESS ('a aexp) ('a aexp)
  1077             | AND ('a bexp) ('a bexp)
  1078             | OR ('a bexp) ('a bexp)
  1079 
  1080 as well as indirectly recursive datatypes such as
  1081 
  1082   datatype
  1083     ('a, 'b) term = Var 'a
  1084                   | App 'b ((('a, 'b) term) list)
  1085 
  1086 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1087 induction on mutually / indirectly recursive datatypes.
  1088 
  1089 Primrec equations are now stored in theory and can be accessed via
  1090 <function_name>.simps.
  1091 
  1092 INCOMPATIBILITIES:
  1093 
  1094   - Theories using datatypes must now have theory Datatype as an
  1095     ancestor.
  1096   - The specific <typename>.induct_tac no longer exists - use the
  1097     generic induct_tac instead.
  1098   - natE has been renamed to nat.exhaust - use exhaust_tac
  1099     instead of res_inst_tac ... natE. Note that the variable
  1100     names in nat.exhaust differ from the names in natE, this
  1101     may cause some "fragile" proofs to fail.
  1102   - The theorems split_<typename>_case and split_<typename>_case_asm
  1103     have been renamed to <typename>.split and <typename>.split_asm.
  1104   - Since default sorts of type variables are now handled correctly,
  1105     some datatype definitions may have to be annotated with explicit
  1106     sort constraints.
  1107   - Primrec definitions no longer require function name and type
  1108     of recursive argument.
  1109 
  1110 Consider using isatool fixdatatype to adapt your theories and proof
  1111 scripts to the new package (backup your sources first!).
  1112 
  1113 
  1114 * HOL/record package: considerably improved implementation; now
  1115 includes concrete syntax for record types, terms, updates; theorems
  1116 for surjective pairing and splitting !!-bound record variables; proof
  1117 support is as follows:
  1118 
  1119   1) standard conversions (selectors or updates applied to record
  1120 constructor terms) are part of the standard simpset;
  1121 
  1122   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1123 made part of standard simpset and claset via addIffs;
  1124 
  1125   3) a tactic for record field splitting (record_split_tac) is part of
  1126 the standard claset (addSWrapper);
  1127 
  1128 To get a better idea about these rules you may retrieve them via
  1129 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1130 the name of your record type.
  1131 
  1132 The split tactic 3) conceptually simplifies by the following rule:
  1133 
  1134   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1135 
  1136 Thus any record variable that is bound by meta-all will automatically
  1137 blow up into some record constructor term, consequently the
  1138 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1139 solve record problems automatically.
  1140 
  1141 
  1142 * reorganized the main HOL image: HOL/Integ and String loaded by
  1143 default; theory Main includes everything;
  1144 
  1145 * automatic simplification of integer sums and comparisons, using cancellation;
  1146 
  1147 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1148 
  1149 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1150 
  1151 * many new identities for unions, intersections, set difference, etc.;
  1152 
  1153 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1154 called split_if, split_split, split_sum_case and split_nat_case (to go
  1155 with add/delsplits);
  1156 
  1157 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1158 (?x::unit) = (); this is made part of the default simpset, which COULD
  1159 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1160 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1161 unit_abs_eta_conv is added in order to counter the effect of
  1162 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1163 %u.f();
  1164 
  1165 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1166 makes more sense);
  1167 
  1168 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1169   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1170   disjointness reasoning but breaking a few old proofs.
  1171 
  1172 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1173 to 'converse' from 'inverse' (for compatibility with ZF and some
  1174 literature);
  1175 
  1176 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1177 the well-founded relation;
  1178 
  1179 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1180     Compl A.  The "Compl" syntax remains available as input syntax for this
  1181     release ONLY.
  1182 
  1183 * HOL/Update: new theory of function updates:
  1184     f(a:=b) == %x. if x=a then b else f x
  1185 may also be iterated as in f(a:=b,c:=d,...);
  1186 
  1187 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1188 
  1189 * HOL/List:
  1190   - new function list_update written xs[i:=v] that updates the i-th
  1191     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1192   - new function `upt' written [i..j(] which generates the list
  1193     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1194     bound write [i..j], which is a shorthand for [i..j+1(].
  1195   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1196 
  1197 * HOL/Arith:
  1198   - removed 'pred' (predecessor) function;
  1199   - generalized some theorems about n-1;
  1200   - many new laws about "div" and "mod";
  1201   - new laws about greatest common divisors (see theory ex/Primes);
  1202 
  1203 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1204 instead of "inverse";
  1205 
  1206 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1207   of the multiset ordering;
  1208 
  1209 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1210   (not included by default);
  1211 
  1212 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1213 
  1214 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1215   programs, i.e. different program variables may have different types.
  1216 
  1217 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1218   [previously, this check worked only if the rewrite rule was unconditional]
  1219   Now rew can involve either definitions or equalities (either == or =).
  1220 
  1221 
  1222 *** ZF ***
  1223 
  1224 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1225   only the theorems proved on ZF.ML;
  1226 
  1227 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1228   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1229   disjointness reasoning but breaking a few old proofs.
  1230 
  1231 * ZF/Update: new theory of function updates
  1232     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1233   may also be iterated as in f(a:=b,c:=d,...);
  1234 
  1235 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1236 
  1237 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1238   [previously, this check worked only if the rewrite rule was unconditional]
  1239   Now rew can involve either definitions or equalities (either == or =).
  1240 
  1241 * case_tac provided for compatibility with HOL
  1242     (like the old excluded_middle_tac, but with subgoals swapped)
  1243 
  1244 
  1245 *** Internal programming interfaces ***
  1246 
  1247 * Pure: several new basic modules made available for general use, see
  1248 also src/Pure/README;
  1249 
  1250 * improved the theory data mechanism to support encapsulation (data
  1251 kind name replaced by private Object.kind, acting as authorization
  1252 key); new type-safe user interface via functor TheoryDataFun; generic
  1253 print_data function becomes basically useless;
  1254 
  1255 * removed global_names compatibility flag -- all theory declarations
  1256 are qualified by default;
  1257 
  1258 * module Pure/Syntax now offers quote / antiquote translation
  1259 functions (useful for Hoare logic etc. with implicit dependencies);
  1260 see HOL/ex/Antiquote for an example use;
  1261 
  1262 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1263 cterm -> thm;
  1264 
  1265 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1266 subgoal;
  1267 
  1268 * Display.print_goals function moved to Locale.print_goals;
  1269 
  1270 * standard print function for goals supports current_goals_markers
  1271 variable for marking begin of proof, end of proof, start of goal; the
  1272 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1273 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1274 for example;
  1275 
  1276 
  1277 
  1278 New in Isabelle98 (January 1998)
  1279 --------------------------------
  1280 
  1281 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1282 
  1283 * changed lexical syntax of terms / types: dots made part of long
  1284 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1285 
  1286 * simpset (and claset) reference variable replaced by functions
  1287 simpset / simpset_ref;
  1288 
  1289 * no longer supports theory aliases (via merge) and non-trivial
  1290 implicit merge of thms' signatures;
  1291 
  1292 * most internal names of constants changed due to qualified names;
  1293 
  1294 * changed Pure/Sequence interface (see Pure/seq.ML);
  1295 
  1296 
  1297 *** General Changes ***
  1298 
  1299 * hierachically structured name spaces (for consts, types, axms, thms
  1300 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1301 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1302 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1303 long_names for fully qualified output names; NOTE: ML programs
  1304 (special tactics, packages etc.) referring to internal names may have
  1305 to be adapted to cope with fully qualified names; in case of severe
  1306 backward campatibility problems try setting 'global_names' at compile
  1307 time to have enrything declared within a flat name space; one may also
  1308 fine tune name declarations in theories via the 'global' and 'local'
  1309 section;
  1310 
  1311 * reimplemented the implicit simpset and claset using the new anytype
  1312 data filed in signatures; references simpset:simpset ref etc. are
  1313 replaced by functions simpset:unit->simpset and
  1314 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1315 to patch your ML files accordingly;
  1316 
  1317 * HTML output now includes theory graph data for display with Java
  1318 applet or isatool browser; data generated automatically via isatool
  1319 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1320 
  1321 * defs may now be conditional; improved rewrite_goals_tac to handle
  1322 conditional equations;
  1323 
  1324 * defs now admits additional type arguments, using TYPE('a) syntax;
  1325 
  1326 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1327 creates a new theory node; implicit merge of thms' signatures is
  1328 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1329 transfer:theory->thm->thm in (rare) cases;
  1330 
  1331 * improved handling of draft signatures / theories; draft thms (and
  1332 ctyps, cterms) are automatically promoted to real ones;
  1333 
  1334 * slightly changed interfaces for oracles: admit many per theory, named
  1335 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1336 
  1337 * print_goals: optional output of const types (set show_consts and
  1338 show_types);
  1339 
  1340 * improved output of warnings (###) and errors (***);
  1341 
  1342 * subgoal_tac displays a warning if the new subgoal has type variables;
  1343 
  1344 * removed old README and Makefiles;
  1345 
  1346 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1347 
  1348 * removed obsolete init_pps and init_database;
  1349 
  1350 * deleted the obsolete tactical STATE, which was declared by
  1351     fun STATE tacfun st = tacfun st st;
  1352 
  1353 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1354 (which abbreviates $HOME);
  1355 
  1356 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1357 use isatool fixseq to adapt your ML programs (this works for fully
  1358 qualified references to the Sequence structure only!);
  1359 
  1360 * use_thy no longer requires writable current directory; it always
  1361 reloads .ML *and* .thy file, if either one is out of date;
  1362 
  1363 
  1364 *** Classical Reasoner ***
  1365 
  1366 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1367 tactics that use classical reasoning to simplify a subgoal without
  1368 splitting it into several subgoals;
  1369 
  1370 * Safe_tac: like safe_tac but uses the default claset;
  1371 
  1372 
  1373 *** Simplifier ***
  1374 
  1375 * added simplification meta rules:
  1376     (asm_)(full_)simplify: simpset -> thm -> thm;
  1377 
  1378 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1379 logics (again);
  1380 
  1381 * added prems argument to simplification procedures;
  1382 
  1383 * HOL, FOL, ZF: added infix function `addsplits':
  1384   instead of `<simpset> setloop (split_tac <thms>)'
  1385   you can simply write `<simpset> addsplits <thms>'
  1386 
  1387 
  1388 *** Syntax ***
  1389 
  1390 * TYPE('a) syntax for type reflection terms;
  1391 
  1392 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1393 
  1394 * pretty printer: changed order of mixfix annotation preference (again!);
  1395 
  1396 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1397 
  1398 
  1399 *** HOL ***
  1400 
  1401 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1402   with `addloop' of the simplifier to faciliate case splitting in premises.
  1403 
  1404 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1405 
  1406 * HOL/Auth: new protocol proofs including some for the Internet
  1407   protocol TLS;
  1408 
  1409 * HOL/Map: new theory of `maps' a la VDM;
  1410 
  1411 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1412 cancelling out common nat summands from =, <, <= (in)equalities, or
  1413 differences; simplification procedures nat_cancel_factor for
  1414 cancelling common factor from =, <, <= (in)equalities over natural
  1415 sums; nat_cancel contains both kinds of procedures, it is installed by
  1416 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1417 
  1418 * HOL/simplifier: terms of the form
  1419   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1420   are rewritten to
  1421   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1422   and those of the form
  1423   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1424   are rewritten to
  1425   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1426 
  1427 * HOL/datatype
  1428   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1429 
  1430   P(t_case f1 ... fn x) =
  1431      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1432         ...
  1433        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1434      )
  1435 
  1436   and a theorem `split_t_case_asm' of the form
  1437 
  1438   P(t_case f1 ... fn x) =
  1439     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1440         ...
  1441        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1442      )
  1443   which can be added to a simpset via `addsplits'. The existing theorems
  1444   expand_list_case and expand_option_case have been renamed to
  1445   split_list_case and split_option_case.
  1446 
  1447 * HOL/Arithmetic:
  1448   - `pred n' is automatically converted to `n-1'.
  1449     Users are strongly encouraged not to use `pred' any longer,
  1450     because it will disappear altogether at some point.
  1451   - Users are strongly encouraged to write "0 < n" rather than
  1452     "n ~= 0". Theorems and proof tools have been modified towards this
  1453     `standard'.
  1454 
  1455 * HOL/Lists:
  1456   the function "set_of_list" has been renamed "set" (and its theorems too);
  1457   the function "nth" now takes its arguments in the reverse order and
  1458   has acquired the infix notation "!" as in "xs!n".
  1459 
  1460 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1461 
  1462 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1463   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1464 
  1465 * HOL/record: extensible records with schematic structural subtyping
  1466 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1467 still lacks various theorems and concrete record syntax;
  1468 
  1469 
  1470 *** HOLCF ***
  1471 
  1472 * removed "axioms" and "generated by" sections;
  1473 
  1474 * replaced "ops" section by extended "consts" section, which is capable of
  1475   handling the continuous function space "->" directly;
  1476 
  1477 * domain package:
  1478   . proves theorems immediately and stores them in the theory,
  1479   . creates hierachical name space,
  1480   . now uses normal mixfix annotations (instead of cinfix...),
  1481   . minor changes to some names and values (for consistency),
  1482   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1483   . separator between mutual domain defs: changed "," to "and",
  1484   . improved handling of sort constraints;  now they have to
  1485     appear on the left-hand side of the equations only;
  1486 
  1487 * fixed LAM <x,y,zs>.b syntax;
  1488 
  1489 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1490 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1491 
  1492 
  1493 *** FOL and ZF ***
  1494 
  1495 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1496   with `addloop' of the simplifier to faciliate case splitting in premises.
  1497 
  1498 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1499 in HOL, they strip ALL and --> from proved theorems;
  1500 
  1501 
  1502 
  1503 New in Isabelle94-8 (May 1997)
  1504 ------------------------------
  1505 
  1506 *** General Changes ***
  1507 
  1508 * new utilities to build / run / maintain Isabelle etc. (in parts
  1509 still somewhat experimental); old Makefiles etc. still functional;
  1510 
  1511 * new 'Isabelle System Manual';
  1512 
  1513 * INSTALL text, together with ./configure and ./build scripts;
  1514 
  1515 * reimplemented type inference for greater efficiency, better error
  1516 messages and clean internal interface;
  1517 
  1518 * prlim command for dealing with lots of subgoals (an easier way of
  1519 setting goals_limit);
  1520 
  1521 
  1522 *** Syntax ***
  1523 
  1524 * supports alternative (named) syntax tables (parser and pretty
  1525 printer); internal interface is provided by add_modesyntax(_i);
  1526 
  1527 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1528 be used in conjunction with the Isabelle symbol font; uses the
  1529 "symbols" syntax table;
  1530 
  1531 * added token_translation interface (may translate name tokens in
  1532 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1533 the current print_mode); IMPORTANT: user print translation functions
  1534 are responsible for marking newly introduced bounds
  1535 (Syntax.mark_boundT);
  1536 
  1537 * token translations for modes "xterm" and "xterm_color" that display
  1538 names in bold, underline etc. or colors (which requires a color
  1539 version of xterm);
  1540 
  1541 * infixes may now be declared with names independent of their syntax;
  1542 
  1543 * added typed_print_translation (like print_translation, but may
  1544 access type of constant);
  1545 
  1546 
  1547 *** Classical Reasoner ***
  1548 
  1549 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1550 some limitations.  Blast_tac...
  1551   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1552   + ignores elimination rules that don't have the correct format
  1553         (the conclusion MUST be a formula variable)
  1554   + ignores types, which can make HOL proofs fail
  1555   + rules must not require higher-order unification, e.g. apply_type in ZF
  1556     [message "Function Var's argument not a bound variable" relates to this]
  1557   + its proof strategy is more general but can actually be slower
  1558 
  1559 * substitution with equality assumptions no longer permutes other
  1560 assumptions;
  1561 
  1562 * minor changes in semantics of addafter (now called addaltern); renamed
  1563 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1564 (and access functions for it);
  1565 
  1566 * improved combination of classical reasoner and simplifier:
  1567   + functions for handling clasimpsets
  1568   + improvement of addss: now the simplifier is called _after_ the
  1569     safe steps.
  1570   + safe variant of addss called addSss: uses safe simplifications
  1571     _during_ the safe steps. It is more complete as it allows multiple
  1572     instantiations of unknowns (e.g. with slow_tac).
  1573 
  1574 *** Simplifier ***
  1575 
  1576 * added interface for simplification procedures (functions that
  1577 produce *proven* rewrite rules on the fly, depending on current
  1578 redex);
  1579 
  1580 * ordering on terms as parameter (used for ordered rewriting);
  1581 
  1582 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1583 
  1584 * the solver is now split into a safe and an unsafe part.
  1585 This should be invisible for the normal user, except that the
  1586 functions setsolver and addsolver have been renamed to setSolver and
  1587 addSolver; added safe_asm_full_simp_tac;
  1588 
  1589 
  1590 *** HOL ***
  1591 
  1592 * a generic induction tactic `induct_tac' which works for all datatypes and
  1593 also for type `nat';
  1594 
  1595 * a generic case distinction tactic `exhaust_tac' which works for all
  1596 datatypes and also for type `nat';
  1597 
  1598 * each datatype comes with a function `size';
  1599 
  1600 * patterns in case expressions allow tuple patterns as arguments to
  1601 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1602 
  1603 * primrec now also works with type nat;
  1604 
  1605 * recdef: a new declaration form, allows general recursive functions to be
  1606 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1607 
  1608 * the constant for negation has been renamed from "not" to "Not" to
  1609 harmonize with FOL, ZF, LK, etc.;
  1610 
  1611 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1612 infinite lists;
  1613 
  1614 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1615 
  1616 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1617 problems in commutative rings, using axiomatic type classes for + and *;
  1618 
  1619 * more examples in HOL/MiniML and HOL/Auth;
  1620 
  1621 * more default rewrite rules for quantifiers, union/intersection;
  1622 
  1623 * a new constant `arbitrary == @x.False';
  1624 
  1625 * HOLCF/IOA replaces old HOL/IOA;
  1626 
  1627 * HOLCF changes: derived all rules and arities
  1628   + axiomatic type classes instead of classes
  1629   + typedef instead of faking type definitions
  1630   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1631   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1632   + eliminated the types void, one, tr
  1633   + use unit lift and bool lift (with translations) instead of one and tr
  1634   + eliminated blift from Lift3.thy (use Def instead of blift)
  1635   all eliminated rules are derived as theorems --> no visible changes ;
  1636 
  1637 
  1638 *** ZF ***
  1639 
  1640 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1641 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1642 as ZF_cs addSIs [equalityI];
  1643 
  1644 
  1645 
  1646 New in Isabelle94-7 (November 96)
  1647 ---------------------------------
  1648 
  1649 * allowing negative levels (as offsets) in prlev and choplev;
  1650 
  1651 * super-linear speedup for large simplifications;
  1652 
  1653 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1654 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1655 FAIL); can suppress it using the command Delsimps (ex_simps @
  1656 all_simps); De Morgan laws are also now included, by default;
  1657 
  1658 * improved printing of ==>  :  ~:
  1659 
  1660 * new object-logic "Sequents" adds linear logic, while replacing LK
  1661 and Modal (thanks to Sara Kalvala);
  1662 
  1663 * HOL/Auth: correctness proofs for authentication protocols;
  1664 
  1665 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1666 examples on HOL/Auth);
  1667 
  1668 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1669 the rewriter and classical reasoner simultaneously;
  1670 
  1671 * function uresult no longer returns theorems in "standard" format;
  1672 regain previous version by: val uresult = standard o uresult;
  1673 
  1674 
  1675 
  1676 New in Isabelle94-6
  1677 -------------------
  1678 
  1679 * oracles -- these establish an interface between Isabelle and trusted
  1680 external reasoners, which may deliver results as theorems;
  1681 
  1682 * proof objects (in particular record all uses of oracles);
  1683 
  1684 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1685 
  1686 * "constdefs" section in theory files;
  1687 
  1688 * "primrec" section (HOL) no longer requires names;
  1689 
  1690 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1691 
  1692 
  1693 
  1694 New in Isabelle94-5
  1695 -------------------
  1696 
  1697 * reduced space requirements;
  1698 
  1699 * automatic HTML generation from theories;
  1700 
  1701 * theory files no longer require "..." (quotes) around most types;
  1702 
  1703 * new examples, including two proofs of the Church-Rosser theorem;
  1704 
  1705 * non-curried (1994) version of HOL is no longer distributed;
  1706 
  1707 
  1708 
  1709 New in Isabelle94-4
  1710 -------------------
  1711 
  1712 * greatly reduced space requirements;
  1713 
  1714 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1715 
  1716 * searchable theorem database (see the section "Retrieving theorems" on
  1717 page 8 of the Reference Manual);
  1718 
  1719 * new examples, including Grabczewski's monumental case study of the
  1720 Axiom of Choice;
  1721 
  1722 * The previous version of HOL renamed to Old_HOL;
  1723 
  1724 * The new version of HOL (previously called CHOL) uses a curried syntax
  1725 for functions.  Application looks like f a b instead of f(a,b);
  1726 
  1727 * Mutually recursive inductive definitions finally work in HOL;
  1728 
  1729 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1730 translates to the operator "split";
  1731 
  1732 
  1733 
  1734 New in Isabelle94-3
  1735 -------------------
  1736 
  1737 * new infix operator, addss, allowing the classical reasoner to
  1738 perform simplification at each step of its search.  Example:
  1739         fast_tac (cs addss ss)
  1740 
  1741 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1742 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1743 look like (a,b) instead of <a,b>;
  1744 
  1745 * PLEASE NOTE: CHOL will eventually replace HOL!
  1746 
  1747 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1748 It translates to the operator "split".  A new theory of integers is available;
  1749 
  1750 * In ZF, integer numerals now denote two's-complement binary integers.
  1751 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1752 
  1753 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1754 of the Axiom of Choice;
  1755 
  1756 
  1757 
  1758 New in Isabelle94-2
  1759 -------------------
  1760 
  1761 * Significantly faster resolution;
  1762 
  1763 * the different sections in a .thy file can now be mixed and repeated
  1764 freely;
  1765 
  1766 * Database of theorems for FOL, HOL and ZF.  New
  1767 commands including qed, qed_goal and bind_thm store theorems in the database.
  1768 
  1769 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1770 a given theory (thms_of), or find out what theory a theorem was proved in
  1771 (theory_of_thm);
  1772 
  1773 * Bugs fixed in the inductive definition and datatype packages;
  1774 
  1775 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1776 and HOL_dup_cs obsolete;
  1777 
  1778 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1779 have been removed;
  1780 
  1781 * Simpler definition of function space in ZF;
  1782 
  1783 * new results about cardinal and ordinal arithmetic in ZF;
  1784 
  1785 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1786 types;
  1787 
  1788 
  1789 $Id$