NEWS
author ballarin
Sat Feb 10 08:48:10 2001 +0100 (2001-02-10)
changeset 11091 45ffef3d3e75
parent 11062 e86340dc1d28
child 11094 b803ef642e60
permissions -rw-r--r--
Updates to HOL/Algebra:
- axclasses consolidated (lemma one_not_zero)
- summation operator SUM removed, now uses setsum
Use of setsum made it necessary to relax sort constraint in its definition
to {zero, plus}.
     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/Algebra: special summation operator SUM no longer exists, it has
    11 been replaced by setsum; infix 'assoc' now has priority 50 (like 'dvd');
    12 
    13 * HOL/Algebra: axiom 'one_not_zero' has been moved from axclass 'ring'
    14 to 'domain', this makes the theory consistent with mathematical literature;
    15  
    16 * HOL: inductive package no longer splits induction rule aggressively,
    17 but only as far as specified by the introductions given; the old
    18 format may recovered via ML function complete_split_rule or attribute
    19 'split_rule (complete)';
    20 
    21 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
    22 gfp_Tarski to gfp_unfold;
    23 
    24 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
    25 
    26 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
    27 relation); infix "^^" has been renamed "``"; infix "``" has been
    28 renamed "`"; "univalent" has been renamed "single_valued";
    29 
    30 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
    31 operation;
    32 
    33 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
    34 
    35 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
    36 
    37 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
    38 consequence, it is no longer monotonic wrt. the local goal context
    39 (which is now passed through the inductive cases);
    40 
    41 * Document preparation: renamed standard symbols \<ll> to \<lless> and
    42 \<gg> to \<ggreater>;
    43 
    44 
    45 *** Document preparation ***
    46 
    47 * \isabellestyle{NAME} selects version of Isabelle output (currently
    48 available: are "it" for near math-mode best-style output, "sl" for
    49 slanted text style, and "tt" for plain type-writer; if no
    50 \isabellestyle command is given, output is according to slanted
    51 type-writer);
    52 
    53 * support sub/super scripts (for single symbols only), input syntax is
    54 like this: "A\<^sup>*" or "A\<^sup>\<star>";
    55 
    56 * some more standard symbols; see Appendix A of the system manual for
    57 the complete list of symbols defined in isabellesym.sty;
    58 
    59 * improved isabelle style files; more abstract symbol implementation
    60 (should now use \isamath{...} and \isatext{...} in custom symbol
    61 definitions);
    62 
    63 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
    64 state; Note that presentation of goal states does not conform to
    65 actual human-readable proof documents.  Please do not include goal
    66 states into document output unless you really know what you are doing!
    67 
    68 * proper indentation of antiquoted output with proportional LaTeX
    69 fonts;
    70 
    71 * no_document ML operator temporarily disables LaTeX document
    72 generation;
    73 
    74 * isatool unsymbolize tunes sources for plain ASCII communication;
    75 
    76 
    77 *** Isar ***
    78 
    79 * Pure: Isar now suffers initial goal statements to contain unbound
    80 schematic variables (this does not conform to actual readable proof
    81 documents, due to unpredictable outcome and non-compositional proof
    82 checking); users who know what they are doing may use schematic goals
    83 for Prolog-style synthesis of proven results;
    84 
    85 * Pure: assumption method (an implicit finishing) now handles actual
    86 rules as well;
    87 
    88 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
    89 initial goal, declare "that" only as Pure intro (only for single
    90 steps); the "that" rule assumption may now be involved in implicit
    91 finishing, thus ".." becomes a feasible for trivial obtains;
    92 
    93 * Pure: default proof step now includes 'intro_classes'; thus trivial
    94 instance proofs may be performed by "..";
    95 
    96 * Pure: ?thesis / ?this / "..." now work for pure meta-level
    97 statements as well;
    98 
    99 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   100 rule (as well as the assumption rule);
   101 
   102 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   103 lemmas, using the graph browser tool;
   104 
   105 * Pure: predict failure of "show" in interactive mode;
   106 
   107 * Pure: 'thms_containing' now takes actual terms as arguments;
   108 
   109 * HOL: improved method 'induct' --- now handles non-atomic goals
   110 (potential INCOMPATIBILITY); tuned error handling;
   111 
   112 * HOL: cases and induct rules now provide explicit hints about the
   113 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   114 any remaining facts are inserted into the goal verbatim;
   115 
   116 * HOL: local contexts (aka cases) may now contain term bindings as
   117 well; the 'cases' and 'induct' methods new provide a ?case binding for
   118 the result to be shown in each case;
   119 
   120 * HOL: added 'recdef_tc' command;
   121 
   122 * isatool convert assists in eliminating legacy ML scripts;
   123 
   124 
   125 *** HOL ***
   126 
   127 * HOL/Library: a collection of generic theories to be used together
   128 with main HOL; the theory loader path already includes this directory
   129 by default; the following existing theories have been moved here:
   130 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   131 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   132 
   133 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   134 modelling and verification task performed in Isabelle/HOL +
   135 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   136 
   137 * HOL basics: added overloaded operations "inverse" and "divide"
   138 (infix "/"), syntax for generic "abs" operation, generic summation
   139 operator;
   140 
   141 * HOL/typedef: simplified package, provide more useful rules (see also
   142 HOL/subset.thy);
   143 
   144 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   145 now expressed as a proper nested rule (old-style tactic scripts may
   146 require atomize_strip_tac to cope with non-atomic premises);
   147 
   148 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   149 to "split_conv" (old name still available for compatibility);
   150 
   151 * HOL: improved concrete syntax for strings (e.g. allows translation
   152 rules with string literals);
   153 
   154 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   155 and Fleuriot's mechanization of analysis;
   156 
   157 * HOL-Real, HOL-Hyperreals: improved arithmetic simplification;
   158 
   159 
   160 *** CTT ***
   161 
   162 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   163 "lam" is displayed as TWO lambda-symbols
   164 
   165 * CTT: theory Main now available, containing everything (that is, Bool
   166 and Arith);
   167 
   168 
   169 *** General ***
   170 
   171 * print modes "brackets" and "no_brackets" control output of nested =>
   172 (types) and ==> (props); the default behaviour is "brackets";
   173 
   174 * system: support Poly/ML 4.0;
   175 
   176 * Pure: the Simplifier has been implemented properly as a derived rule
   177 outside of the actual kernel (at last!); the overall performance
   178 penalty in practical applications is about 50%, while reliability of
   179 the Isabelle inference kernel has been greatly improved;
   180 
   181 * Provers: fast_tac (and friends) now handle actual object-logic rules
   182 as assumptions as well;
   183 
   184 
   185 
   186 New in Isabelle99-1 (October 2000)
   187 ----------------------------------
   188 
   189 *** Overview of INCOMPATIBILITIES ***
   190 
   191 * HOL: simplification of natural numbers is much changed; to partly
   192 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   193 issue the following ML commands:
   194 
   195   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   196   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   197 
   198 * HOL: simplification no longer dives into case-expressions; this is
   199 controlled by "t.weak_case_cong" for each datatype t;
   200 
   201 * HOL: nat_less_induct renamed to less_induct;
   202 
   203 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   204 fixsome to patch .thy and .ML sources automatically;
   205 
   206   select_equality  -> some_equality
   207   select_eq_Ex     -> some_eq_ex
   208   selectI2EX       -> someI2_ex
   209   selectI2         -> someI2
   210   selectI          -> someI
   211   select1_equality -> some1_equality
   212   Eps_sym_eq       -> some_sym_eq_trivial
   213   Eps_eq           -> some_eq_trivial
   214 
   215 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   216 
   217 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   218 instead);
   219 
   220 * HOL: the recursion equations generated by 'recdef' are now called
   221 f.simps instead of f.rules;
   222 
   223 * HOL: qed_spec_mp now also handles bounded ALL as well;
   224 
   225 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   226 sometimes be needed;
   227 
   228 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   229 
   230 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   231 
   232 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   233 product is now "<*>" instead of "Times"; the lexicographic product is
   234 now "<*lex*>" instead of "**";
   235 
   236 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   237 of main HOL, but was unused); better use HOL's datatype package;
   238 
   239 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   240 the old syntax may be recovered as follows:
   241 
   242   syntax (symbols)
   243     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   244       (infixl "\\<oplus>" 100)
   245 
   246 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   247 
   248 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   249 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   250 internally;
   251 
   252 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   253 changed from A/r to A//r;
   254 
   255 * ZF: new treatment of arithmetic (nat & int) may break some old
   256 proofs;
   257 
   258 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   259 rulify -> rule_format, elimify -> elim_format, ...);
   260 
   261 * Isar/Provers: intro/elim/dest attributes changed; renamed
   262 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   263 should have to change intro!! to intro? only); replaced "delrule" by
   264 "rule del";
   265 
   266 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   267 
   268 * Provers: strengthened force_tac by using new first_best_tac;
   269 
   270 * LaTeX document preparation: several changes of isabelle.sty (see
   271 lib/texinputs);
   272 
   273 
   274 *** Document preparation ***
   275 
   276 * formal comments (text blocks etc.) in new-style theories may now
   277 contain antiquotations of thm/prop/term/typ/text to be presented
   278 according to latex print mode; concrete syntax is like this:
   279 @{term[show_types] "f(x) = a + x"};
   280 
   281 * isatool mkdir provides easy setup of Isabelle session directories,
   282 including proper document sources;
   283 
   284 * generated LaTeX sources are now deleted after successful run
   285 (isatool document -c); may retain a copy somewhere else via -D option
   286 of isatool usedir;
   287 
   288 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   289 style files, achieving self-contained LaTeX sources and simplifying
   290 LaTeX debugging;
   291 
   292 * old-style theories now produce (crude) LaTeX output as well;
   293 
   294 * browser info session directories are now self-contained (may be put
   295 on WWW server seperately); improved graphs of nested sessions; removed
   296 graph for 'all sessions';
   297 
   298 * several improvements in isabelle style files; \isabellestyle{it}
   299 produces fake math mode output; \isamarkupheader is now \section by
   300 default; see lib/texinputs/isabelle.sty etc.;
   301 
   302 
   303 *** Isar ***
   304 
   305 * Isar/Pure: local results and corresponding term bindings are now
   306 subject to Hindley-Milner polymorphism (similar to ML); this
   307 accommodates incremental type-inference very nicely;
   308 
   309 * Isar/Pure: new derived language element 'obtain' supports
   310 generalized existence reasoning;
   311 
   312 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   313 support accumulation of results, without applying any rules yet;
   314 useful to collect intermediate results without explicit name
   315 references, and for use with transitivity rules with more than 2
   316 premises;
   317 
   318 * Isar/Pure: scalable support for case-analysis type proofs: new
   319 'case' language element refers to local contexts symbolically, as
   320 produced by certain proof methods; internally, case names are attached
   321 to theorems as "tags";
   322 
   323 * Isar/Pure: theory command 'hide' removes declarations from
   324 class/type/const name spaces;
   325 
   326 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   327 indicate potential overloading;
   328 
   329 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   330 
   331 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   332 "{a,b,c}" instead of {a,b,c};
   333 
   334 * Isar/Pure now provides its own version of intro/elim/dest
   335 attributes; useful for building new logics, but beware of confusion
   336 with the version in Provers/classical;
   337 
   338 * Isar/Pure: the local context of (non-atomic) goals is provided via
   339 case name 'antecedent';
   340 
   341 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   342 to the current context is now done automatically);
   343 
   344 * Isar/Pure: theory command 'method_setup' provides a simple interface
   345 for definining proof methods in ML;
   346 
   347 * Isar/Provers: intro/elim/dest attributes changed; renamed
   348 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   349 most cases, one should have to change intro!! to intro? only);
   350 replaced "delrule" by "rule del";
   351 
   352 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   353 'symmetric' attribute (the latter supercedes [RS sym]);
   354 
   355 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   356 method modifier); 'simp' method: 'only:' modifier removes loopers as
   357 well (including splits);
   358 
   359 * Isar/Provers: Simplifier and Classical methods now support all kind
   360 of modifiers used in the past, including 'cong', 'iff', etc.
   361 
   362 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   363 of Simplifier and Classical reasoner);
   364 
   365 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   366 now support named cases; major packages (inductive, datatype, primrec,
   367 recdef) support case names and properly name parameters;
   368 
   369 * Isar/HOL: new transitivity rules for substitution in inequalities --
   370 monotonicity conditions are extracted to be proven at end of
   371 calculations;
   372 
   373 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   374 method anyway;
   375 
   376 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   377 split_if split_if_asm; datatype package provides theorems foo.splits =
   378 foo.split foo.split_asm for each datatype;
   379 
   380 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   381 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   382 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   383 use "(cases (simplified))" method in proper proof texts);
   384 
   385 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   386 
   387 * Isar: names of theorems etc. may be natural numbers as well;
   388 
   389 * Isar: 'pr' command: optional arguments for goals_limit and
   390 ProofContext.prems_limit; no longer prints theory contexts, but only
   391 proof states;
   392 
   393 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   394 additional print modes to be specified; e.g. "pr(latex)" will print
   395 proof state according to the Isabelle LaTeX style;
   396 
   397 * Isar: improved support for emulating tactic scripts, including proof
   398 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   399 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   400 (for HOL datatypes);
   401 
   402 * Isar: simplified (more robust) goal selection of proof methods: 1st
   403 goal, all goals, or explicit goal specifier (tactic emulation); thus
   404 'proof method scripts' have to be in depth-first order;
   405 
   406 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   407 
   408 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   409 should instead use individual commands for printing items
   410 (print_commands, print_methods etc.);
   411 
   412 * Isar: added 'nothing' --- the empty list of theorems;
   413 
   414 
   415 *** HOL ***
   416 
   417 * HOL/MicroJava: formalization of a fragment of Java, together with a
   418 corresponding virtual machine and a specification of its bytecode
   419 verifier and a lightweight bytecode verifier, including proofs of
   420 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   421 Cornelia Pusch (see also the homepage of project Bali at
   422 http://isabelle.in.tum.de/Bali/);
   423 
   424 * HOL/Algebra: new theory of rings and univariate polynomials, by
   425 Clemens Ballarin;
   426 
   427 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   428 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   429 Rasmussen;
   430 
   431 * HOL/Lattice: fundamental concepts of lattice theory and order
   432 structures, including duals, properties of bounds versus algebraic
   433 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   434 Theorem for complete lattices etc.; may also serve as a demonstration
   435 for abstract algebraic reasoning using axiomatic type classes, and
   436 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   437 
   438 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   439 von Oheimb;
   440 
   441 * HOL/IMPP: extension of IMP with local variables and mutually
   442 recursive procedures, by David von Oheimb;
   443 
   444 * HOL/Lambda: converted into new-style theory and document;
   445 
   446 * HOL/ex/Multiquote: example of multiple nested quotations and
   447 anti-quotations -- basically a generalized version of de-Bruijn
   448 representation; very useful in avoiding lifting of operations;
   449 
   450 * HOL/record: added general record equality rule to simpset; fixed
   451 select-update simplification procedure to handle extended records as
   452 well; admit "r" as field name;
   453 
   454 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   455 other numeric types and also as the identity of groups, rings, etc.;
   456 
   457 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   458 Types nat and int belong to this axclass;
   459 
   460 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   461    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   462    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   463   two terms #m*u and #n*u are replaced by #(m+n)*u
   464     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   465   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   466     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   467 
   468 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   469 powerful prover for predicate logic but knows nothing of clasets; see
   470 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   471 
   472 * HOL: new version of "case_tac" subsumes both boolean case split and
   473 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   474 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   475 
   476 * HOL: simplification no longer dives into case-expressions: only the
   477 selector expression is simplified, but not the remaining arms; to
   478 enable full simplification of case-expressions for datatype t, you may
   479 remove t.weak_case_cong from the simpset, either globally (Delcongs
   480 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   481 
   482 * HOL/recdef: the recursion equations generated by 'recdef' for
   483 function 'f' are now called f.simps instead of f.rules; if all
   484 termination conditions are proved automatically, these simplification
   485 rules are added to the simpset, as in primrec; rules may be named
   486 individually as well, resulting in a separate list of theorems for
   487 each equation;
   488 
   489 * HOL/While is a new theory that provides a while-combinator. It
   490 permits the definition of tail-recursive functions without the
   491 provision of a termination measure. The latter is necessary once the
   492 invariant proof rule for while is applied.
   493 
   494 * HOL: new (overloaded) notation for the set of elements below/above
   495 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   496 
   497 * HOL: theorems impI, allI, ballI bound as "strip";
   498 
   499 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   500 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   501 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   502 
   503 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   504 
   505 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   506 main HOL, but was unused);
   507 
   508 * HOL: fewer consts declared as global (e.g. have to refer to
   509 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   510 
   511 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   512 in case of overlap with user translations (e.g. judgements over
   513 tuples); (note that the underlying logical represenation is still
   514 bogus);
   515 
   516 
   517 *** ZF ***
   518 
   519 * ZF: simplification automatically cancels common terms in arithmetic
   520 expressions over nat and int;
   521 
   522 * ZF: new treatment of nat to minimize type-checking: all operators
   523 coerce their operands to a natural number using the function natify,
   524 making the algebraic laws unconditional;
   525 
   526 * ZF: as above, for int: operators coerce their operands to an integer
   527 using the function intify;
   528 
   529 * ZF: the integer library now contains many of the usual laws for the
   530 orderings, including $<=, and monotonicity laws for $+ and $*;
   531 
   532 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   533 simplification;
   534 
   535 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   536 to the simplifier and classical reasoner simultaneously;
   537 
   538 
   539 *** General ***
   540 
   541 * Provers: blast_tac now handles actual object-logic rules as
   542 assumptions; note that auto_tac uses blast_tac internally as well;
   543 
   544 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   545 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   546 
   547 * Provers: delrules now handles destruct rules as well (no longer need
   548 explicit make_elim);
   549 
   550 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   551   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   552 use instead the strong form,
   553   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   554 in HOL, FOL and ZF the function cla_make_elim will create such rules
   555 from destruct-rules;
   556 
   557 * Provers: Simplifier.easy_setup provides a fast path to basic
   558 Simplifier setup for new object-logics;
   559 
   560 * Pure: AST translation rules no longer require constant head on LHS;
   561 
   562 * Pure: improved name spaces: ambiguous output is qualified; support
   563 for hiding of names;
   564 
   565 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   566 XSYMBOL_HOME; no longer need to do manual configuration in most
   567 situations;
   568 
   569 * system: compression of ML heaps images may now be controlled via -c
   570 option of isabelle and isatool usedir (currently only observed by
   571 Poly/ML);
   572 
   573 * system: isatool installfonts may handle X-Symbol fonts as well (very
   574 useful for remote X11);
   575 
   576 * system: provide TAGS file for Isabelle sources;
   577 
   578 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   579 order;
   580 
   581 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   582 timing flag supersedes proof_timing and Toplevel.trace;
   583 
   584 * ML: new combinators |>> and |>>> for incremental transformations
   585 with secondary results (e.g. certain theory extensions):
   586 
   587 * ML: PureThy.add_defs gets additional argument to indicate potential
   588 overloading (usually false);
   589 
   590 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   591 results;
   592 
   593 
   594 
   595 New in Isabelle99 (October 1999)
   596 --------------------------------
   597 
   598 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   599 
   600 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   601 are no longer simplified.  (This allows the simplifier to unfold recursive
   602 functional programs.)  To restore the old behaviour, declare
   603 
   604     Delcongs [if_weak_cong];
   605 
   606 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   607 complement;
   608 
   609 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   610 
   611 * HOL/datatype: mutual_induct_tac no longer exists --
   612   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   613 
   614 * HOL/typedef: fixed type inference for representing set; type
   615 arguments now have to occur explicitly on the rhs as type constraints;
   616 
   617 * ZF: The con_defs part of an inductive definition may no longer refer
   618 to constants declared in the same theory;
   619 
   620 * HOL, ZF: the function mk_cases, generated by the inductive
   621 definition package, has lost an argument.  To simplify its result, it
   622 uses the default simpset instead of a supplied list of theorems.
   623 
   624 * HOL/List: the constructors of type list are now Nil and Cons;
   625 
   626 * Simplifier: the type of the infix ML functions
   627         setSSolver addSSolver setSolver addSolver
   628 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   629 for packaging solvers. A solver is created via
   630         mk_solver: string -> (thm list -> int -> tactic) -> solver
   631 where the string argument is only a comment.
   632 
   633 
   634 *** Proof tools ***
   635 
   636 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   637 decision procedure for linear arithmetic. Currently it is used for
   638 types `nat', `int', and `real' in HOL (see below); it can, should and
   639 will be instantiated for other types and logics as well.
   640 
   641 * The simplifier now accepts rewrite rules with flexible heads, eg
   642      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   643   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   644   matching.
   645 
   646 
   647 *** General ***
   648 
   649 * New Isabelle/Isar subsystem provides an alternative to traditional
   650 tactical theorem proving; together with the ProofGeneral/isar user
   651 interface it offers an interactive environment for developing human
   652 readable proof documents (Isar == Intelligible semi-automated
   653 reasoning); for further information see isatool doc isar-ref,
   654 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   655 
   656 * improved and simplified presentation of theories: better HTML markup
   657 (including colors), graph views in several sizes; isatool usedir now
   658 provides a proper interface for user theories (via -P option); actual
   659 document preparation based on (PDF)LaTeX is available as well (for
   660 new-style theories only); see isatool doc system for more information;
   661 
   662 * native support for Proof General, both for classic Isabelle and
   663 Isabelle/Isar;
   664 
   665 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   666 using the graph browser tool;
   667 
   668 * Isabelle manuals now also available as PDF;
   669 
   670 * theory loader rewritten from scratch (may not be fully
   671 bug-compatible); old loadpath variable has been replaced by show_path,
   672 add_path, del_path, reset_path functions; new operations such as
   673 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   674 isatool doc ref);
   675 
   676 * improved isatool install: option -k creates KDE application icon,
   677 option -p DIR installs standalone binaries;
   678 
   679 * added ML_PLATFORM setting (useful for cross-platform installations);
   680 more robust handling of platform specific ML images for SML/NJ;
   681 
   682 * the settings environment is now statically scoped, i.e. it is never
   683 created again in sub-processes invoked from isabelle, isatool, or
   684 Isabelle;
   685 
   686 * path element specification '~~' refers to '$ISABELLE_HOME';
   687 
   688 * in locales, the "assumes" and "defines" parts may be omitted if
   689 empty;
   690 
   691 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   692 long arrows);
   693 
   694 * new print_mode "HTML";
   695 
   696 * new flag show_tags controls display of tags of theorems (which are
   697 basically just comments that may be attached by some tools);
   698 
   699 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   700 mode and goal output format:
   701 
   702 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   703 244c244
   704 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   705 ---
   706 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   707 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   708 181c181
   709 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   710 ---
   711 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   712 
   713 * function bind_thms stores lists of theorems (cf. bind_thm);
   714 
   715 * new shorthand tactics ftac, eatac, datac, fatac;
   716 
   717 * qed (and friends) now accept "" as result name; in that case the
   718 theorem is not stored, but proper checks and presentation of the
   719 result still apply;
   720 
   721 * theorem database now also indexes constants "Trueprop", "all",
   722 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   723 
   724 
   725 *** HOL ***
   726 
   727 ** HOL arithmetic **
   728 
   729 * There are now decision procedures for linear arithmetic over nat and
   730 int:
   731 
   732 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   733 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   734 are treated as atomic; subformulae not involving type `nat' or `int'
   735 are ignored; quantified subformulae are ignored unless they are
   736 positive universal or negative existential. The tactic has to be
   737 invoked by hand and can be a little bit slow. In particular, the
   738 running time is exponential in the number of occurrences of `min' and
   739 `max', and `-' on `nat'.
   740 
   741 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   742 (negated) (in)equalities among the premises and the conclusion into
   743 account (i.e. no compound formulae) and does not know about `min' and
   744 `max', and `-' on `nat'. It is fast and is used automatically by the
   745 simplifier.
   746 
   747 NB: At the moment, these decision procedures do not cope with mixed
   748 nat/int formulae where the two parts interact, such as `m < n ==>
   749 int(m) < int(n)'.
   750 
   751 * HOL/Numeral provides a generic theory of numerals (encoded
   752 efficiently as bit strings); setup for types nat/int/real is in place;
   753 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   754 int, existing theories and proof scripts may require a few additional
   755 type constraints;
   756 
   757 * integer division and remainder can now be performed on constant
   758 arguments;
   759 
   760 * many properties of integer multiplication, division and remainder
   761 are now available;
   762 
   763 * An interface to the Stanford Validity Checker (SVC) is available through the
   764 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   765 are proved automatically.  SVC must be installed separately, and its results
   766 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   767 invocation of the underlying oracle).  For SVC see
   768   http://verify.stanford.edu/SVC
   769 
   770 * IsaMakefile: the HOL-Real target now builds an actual image;
   771 
   772 
   773 ** HOL misc **
   774 
   775 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   776 (in Isabelle/Isar) -- by Gertrud Bauer;
   777 
   778 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   779 analysis for assembly languages with subtypes;
   780 
   781 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   782 -- avoids syntactic ambiguities and treats state, transition, and
   783 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   784 changed syntax and (many) tactics;
   785 
   786 * HOL/inductive: Now also handles more general introduction rules such
   787   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   788   theorems are now maintained within the theory (maintained via the
   789   "mono" attribute);
   790 
   791 * HOL/datatype: Now also handles arbitrarily branching datatypes
   792   (using function types) such as
   793 
   794   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   795 
   796 * HOL/record: record_simproc (part of the default simpset) takes care
   797 of selectors applied to updated records; record_split_tac is no longer
   798 part of the default claset; update_defs may now be removed from the
   799 simpset in many cases; COMPATIBILITY: old behavior achieved by
   800 
   801   claset_ref () := claset() addSWrapper record_split_wrapper;
   802   Delsimprocs [record_simproc]
   803 
   804 * HOL/typedef: fixed type inference for representing set; type
   805 arguments now have to occur explicitly on the rhs as type constraints;
   806 
   807 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   808 names rather than an ML expression;
   809 
   810 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   811 supplied later.  Program schemes can be defined, such as
   812     "While B C s = (if B s then While B C (C s) else s)"
   813 where the well-founded relation can be chosen after B and C have been given.
   814 
   815 * HOL/List: the constructors of type list are now Nil and Cons;
   816 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   817 course, ML tools referring to List.list.op # etc. have to be adapted;
   818 
   819 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   820 disabled by default; run isabelle with option -m HOL to get back to
   821 the original Gordon/HOL-style output;
   822 
   823 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   824 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   825 
   826 * HOL basic syntax simplified (more orthogonal): all variants of
   827 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   828 Eps operator is provided as well: "SOME x. P[x]";
   829 
   830 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   831 
   832 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   833 thus available for user theories;
   834 
   835 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   836 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   837 time;
   838 
   839 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   840 several times and then mp;
   841 
   842 
   843 *** LK ***
   844 
   845 * the notation <<...>> is now available as a notation for sequences of
   846 formulas;
   847 
   848 * the simplifier is now installed
   849 
   850 * the axiom system has been generalized (thanks to Soren Heilmann)
   851 
   852 * the classical reasoner now has a default rule database
   853 
   854 
   855 *** ZF ***
   856 
   857 * new primrec section allows primitive recursive functions to be given
   858 directly (as in HOL) over datatypes and the natural numbers;
   859 
   860 * new tactics induct_tac and exhaust_tac for induction (or case
   861 analysis) over datatypes and the natural numbers;
   862 
   863 * the datatype declaration of type T now defines the recursor T_rec;
   864 
   865 * simplification automatically does freeness reasoning for datatype
   866 constructors;
   867 
   868 * automatic type-inference, with AddTCs command to insert new
   869 type-checking rules;
   870 
   871 * datatype introduction rules are now added as Safe Introduction rules
   872 to the claset;
   873 
   874 * the syntax "if P then x else y" is now available in addition to
   875 if(P,x,y);
   876 
   877 
   878 *** Internal programming interfaces ***
   879 
   880 * tuned simplifier trace output; new flag debug_simp;
   881 
   882 * structures Vartab / Termtab (instances of TableFun) offer efficient
   883 tables indexed by indexname_ord / term_ord (compatible with aconv);
   884 
   885 * AxClass.axclass_tac lost the theory argument;
   886 
   887 * tuned current_goals_markers semantics: begin / end goal avoids
   888 printing empty lines;
   889 
   890 * removed prs and prs_fn hook, which was broken because it did not
   891 include \n in its semantics, forcing writeln to add one
   892 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   893 string -> unit if you really want to output text without newline;
   894 
   895 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   896 plain output, interface builders may have to enable 'isabelle_font'
   897 mode to get Isabelle font glyphs as before;
   898 
   899 * refined token_translation interface; INCOMPATIBILITY: output length
   900 now of type real instead of int;
   901 
   902 * theory loader actions may be traced via new ThyInfo.add_hook
   903 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   904 your own database of information attached to *whole* theories -- as
   905 opposed to intra-theory data slots offered via TheoryDataFun;
   906 
   907 * proper handling of dangling sort hypotheses (at last!);
   908 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   909 extra sort hypotheses that can be witnessed from the type signature;
   910 the force_strip_shyps flag is gone, any remaining shyps are simply
   911 left in the theorem (with a warning issued by strip_shyps_warning);
   912 
   913 
   914 
   915 New in Isabelle98-1 (October 1998)
   916 ----------------------------------
   917 
   918 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   919 
   920 * several changes of automated proof tools;
   921 
   922 * HOL: major changes to the inductive and datatype packages, including
   923 some minor incompatibilities of theory syntax;
   924 
   925 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   926 called `inj_on';
   927 
   928 * HOL: removed duplicate thms in Arith:
   929   less_imp_add_less  should be replaced by  trans_less_add1
   930   le_imp_add_le      should be replaced by  trans_le_add1
   931 
   932 * HOL: unary minus is now overloaded (new type constraints may be
   933 required);
   934 
   935 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   936 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   937 now taken as an integer constant.
   938 
   939 * Pure: ML function 'theory_of' renamed to 'theory';
   940 
   941 
   942 *** Proof tools ***
   943 
   944 * Simplifier:
   945   1. Asm_full_simp_tac is now more aggressive.
   946      1. It will sometimes reorient premises if that increases their power to
   947         simplify.
   948      2. It does no longer proceed strictly from left to right but may also
   949         rotate premises to achieve further simplification.
   950      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   951      old Asm_full_simp_tac in that it does not rotate premises.
   952   2. The simplifier now knows a little bit about nat-arithmetic.
   953 
   954 * Classical reasoner: wrapper mechanism for the classical reasoner now
   955 allows for selected deletion of wrappers, by introduction of names for
   956 wrapper functionals.  This implies that addbefore, addSbefore,
   957 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   958 and that adding two tactics with the same name overwrites the first
   959 one (emitting a warning).
   960   type wrapper = (int -> tactic) -> (int -> tactic)
   961   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   962   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   963   delWrapper, delSWrapper: claset *  string            -> claset
   964   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   965 
   966 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   967 semantics; addbefore now affects only the unsafe part of step_tac
   968 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   969 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   970 by Force_tac;
   971 
   972 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   973 compWrapper; added safe wrapper (and access functions for it);
   974 
   975 * HOL/split_all_tac is now much faster and fails if there is nothing
   976 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   977 and the names of the automatically generated variables have changed.
   978 split_all_tac has moved within claset() from unsafe wrappers to safe
   979 wrappers, which means that !!-bound variables are split much more
   980 aggressively, and safe_tac and clarify_tac now split such variables.
   981 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   982 Note: the same holds for record_split_tac, which does the job of
   983 split_all_tac for record fields.
   984 
   985 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   986 permanently to the default simpset using Addsplits just like
   987 Addsimps. They can be removed via Delsplits just like
   988 Delsimps. Lower-case versions are also available.
   989 
   990 * HOL/Simplifier: The rule split_if is now part of the default
   991 simpset. This means that the simplifier will eliminate all occurrences
   992 of if-then-else in the conclusion of a goal. To prevent this, you can
   993 either remove split_if completely from the default simpset by
   994 `Delsplits [split_if]' or remove it in a specific call of the
   995 simplifier using `... delsplits [split_if]'.  You can also add/delete
   996 other case splitting rules to/from the default simpset: every datatype
   997 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   998 t is the name of the datatype).
   999 
  1000 * Classical reasoner / Simplifier combination: new force_tac (and
  1001 derivatives Force_tac, force) combines rewriting and classical
  1002 reasoning (and whatever other tools) similarly to auto_tac, but is
  1003 aimed to solve the given subgoal completely.
  1004 
  1005 
  1006 *** General ***
  1007 
  1008 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1009 and `goalw': the theory is no longer needed as an explicit argument -
  1010 the current theory context is used; assumptions are no longer returned
  1011 at the ML-level unless one of them starts with ==> or !!; it is
  1012 recommended to convert to these new commands using isatool fixgoal
  1013 (backup your sources first!);
  1014 
  1015 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1016 the current theory context, and 'theory' to lookup stored theories;
  1017 
  1018 * new theory section 'locale' for declaring constants, assumptions and
  1019 definitions that have local scope;
  1020 
  1021 * new theory section 'nonterminals' for purely syntactic types;
  1022 
  1023 * new theory section 'setup' for generic ML setup functions
  1024 (e.g. package initialization);
  1025 
  1026 * the distribution now includes Isabelle icons: see
  1027 lib/logo/isabelle-{small,tiny}.xpm;
  1028 
  1029 * isatool install - install binaries with absolute references to
  1030 ISABELLE_HOME/bin;
  1031 
  1032 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1033 
  1034 * print mode 'emacs' reserved for Isamode;
  1035 
  1036 * support multiple print (ast) translations per constant name;
  1037 
  1038 * theorems involving oracles are now printed with a suffixed [!];
  1039 
  1040 
  1041 *** HOL ***
  1042 
  1043 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1044 
  1045 * HOL/inductive package reorganized and improved: now supports mutual
  1046 definitions such as
  1047 
  1048   inductive EVEN ODD
  1049     intrs
  1050       null "0 : EVEN"
  1051       oddI "n : EVEN ==> Suc n : ODD"
  1052       evenI "n : ODD ==> Suc n : EVEN"
  1053 
  1054 new theorem list "elims" contains an elimination rule for each of the
  1055 recursive sets; inductive definitions now handle disjunctive premises
  1056 correctly (also ZF);
  1057 
  1058 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1059 "mutual_induct" no longer exists - the induction rule is always
  1060 contained in "induct";
  1061 
  1062 
  1063 * HOL/datatype package re-implemented and greatly improved: now
  1064 supports mutually recursive datatypes such as
  1065 
  1066   datatype
  1067     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1068             | SUM ('a aexp) ('a aexp)
  1069             | DIFF ('a aexp) ('a aexp)
  1070             | NUM 'a
  1071   and
  1072     'a bexp = LESS ('a aexp) ('a aexp)
  1073             | AND ('a bexp) ('a bexp)
  1074             | OR ('a bexp) ('a bexp)
  1075 
  1076 as well as indirectly recursive datatypes such as
  1077 
  1078   datatype
  1079     ('a, 'b) term = Var 'a
  1080                   | App 'b ((('a, 'b) term) list)
  1081 
  1082 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1083 induction on mutually / indirectly recursive datatypes.
  1084 
  1085 Primrec equations are now stored in theory and can be accessed via
  1086 <function_name>.simps.
  1087 
  1088 INCOMPATIBILITIES:
  1089 
  1090   - Theories using datatypes must now have theory Datatype as an
  1091     ancestor.
  1092   - The specific <typename>.induct_tac no longer exists - use the
  1093     generic induct_tac instead.
  1094   - natE has been renamed to nat.exhaust - use exhaust_tac
  1095     instead of res_inst_tac ... natE. Note that the variable
  1096     names in nat.exhaust differ from the names in natE, this
  1097     may cause some "fragile" proofs to fail.
  1098   - The theorems split_<typename>_case and split_<typename>_case_asm
  1099     have been renamed to <typename>.split and <typename>.split_asm.
  1100   - Since default sorts of type variables are now handled correctly,
  1101     some datatype definitions may have to be annotated with explicit
  1102     sort constraints.
  1103   - Primrec definitions no longer require function name and type
  1104     of recursive argument.
  1105 
  1106 Consider using isatool fixdatatype to adapt your theories and proof
  1107 scripts to the new package (backup your sources first!).
  1108 
  1109 
  1110 * HOL/record package: considerably improved implementation; now
  1111 includes concrete syntax for record types, terms, updates; theorems
  1112 for surjective pairing and splitting !!-bound record variables; proof
  1113 support is as follows:
  1114 
  1115   1) standard conversions (selectors or updates applied to record
  1116 constructor terms) are part of the standard simpset;
  1117 
  1118   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1119 made part of standard simpset and claset via addIffs;
  1120 
  1121   3) a tactic for record field splitting (record_split_tac) is part of
  1122 the standard claset (addSWrapper);
  1123 
  1124 To get a better idea about these rules you may retrieve them via
  1125 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1126 the name of your record type.
  1127 
  1128 The split tactic 3) conceptually simplifies by the following rule:
  1129 
  1130   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1131 
  1132 Thus any record variable that is bound by meta-all will automatically
  1133 blow up into some record constructor term, consequently the
  1134 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1135 solve record problems automatically.
  1136 
  1137 
  1138 * reorganized the main HOL image: HOL/Integ and String loaded by
  1139 default; theory Main includes everything;
  1140 
  1141 * automatic simplification of integer sums and comparisons, using cancellation;
  1142 
  1143 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1144 
  1145 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1146 
  1147 * many new identities for unions, intersections, set difference, etc.;
  1148 
  1149 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1150 called split_if, split_split, split_sum_case and split_nat_case (to go
  1151 with add/delsplits);
  1152 
  1153 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1154 (?x::unit) = (); this is made part of the default simpset, which COULD
  1155 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1156 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1157 unit_abs_eta_conv is added in order to counter the effect of
  1158 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1159 %u.f();
  1160 
  1161 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1162 makes more sense);
  1163 
  1164 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1165   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1166   disjointness reasoning but breaking a few old proofs.
  1167 
  1168 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1169 to 'converse' from 'inverse' (for compatibility with ZF and some
  1170 literature);
  1171 
  1172 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1173 the well-founded relation;
  1174 
  1175 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1176     Compl A.  The "Compl" syntax remains available as input syntax for this
  1177     release ONLY.
  1178 
  1179 * HOL/Update: new theory of function updates:
  1180     f(a:=b) == %x. if x=a then b else f x
  1181 may also be iterated as in f(a:=b,c:=d,...);
  1182 
  1183 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1184 
  1185 * HOL/List:
  1186   - new function list_update written xs[i:=v] that updates the i-th
  1187     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1188   - new function `upt' written [i..j(] which generates the list
  1189     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1190     bound write [i..j], which is a shorthand for [i..j+1(].
  1191   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1192 
  1193 * HOL/Arith:
  1194   - removed 'pred' (predecessor) function;
  1195   - generalized some theorems about n-1;
  1196   - many new laws about "div" and "mod";
  1197   - new laws about greatest common divisors (see theory ex/Primes);
  1198 
  1199 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1200 instead of "inverse";
  1201 
  1202 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1203   of the multiset ordering;
  1204 
  1205 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1206   (not included by default);
  1207 
  1208 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1209 
  1210 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1211   programs, i.e. different program variables may have different types.
  1212 
  1213 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1214   [previously, this check worked only if the rewrite rule was unconditional]
  1215   Now rew can involve either definitions or equalities (either == or =).
  1216 
  1217 
  1218 *** ZF ***
  1219 
  1220 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1221   only the theorems proved on ZF.ML;
  1222 
  1223 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1224   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1225   disjointness reasoning but breaking a few old proofs.
  1226 
  1227 * ZF/Update: new theory of function updates
  1228     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1229   may also be iterated as in f(a:=b,c:=d,...);
  1230 
  1231 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1232 
  1233 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1234   [previously, this check worked only if the rewrite rule was unconditional]
  1235   Now rew can involve either definitions or equalities (either == or =).
  1236 
  1237 * case_tac provided for compatibility with HOL
  1238     (like the old excluded_middle_tac, but with subgoals swapped)
  1239 
  1240 
  1241 *** Internal programming interfaces ***
  1242 
  1243 * Pure: several new basic modules made available for general use, see
  1244 also src/Pure/README;
  1245 
  1246 * improved the theory data mechanism to support encapsulation (data
  1247 kind name replaced by private Object.kind, acting as authorization
  1248 key); new type-safe user interface via functor TheoryDataFun; generic
  1249 print_data function becomes basically useless;
  1250 
  1251 * removed global_names compatibility flag -- all theory declarations
  1252 are qualified by default;
  1253 
  1254 * module Pure/Syntax now offers quote / antiquote translation
  1255 functions (useful for Hoare logic etc. with implicit dependencies);
  1256 see HOL/ex/Antiquote for an example use;
  1257 
  1258 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1259 cterm -> thm;
  1260 
  1261 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1262 subgoal;
  1263 
  1264 * Display.print_goals function moved to Locale.print_goals;
  1265 
  1266 * standard print function for goals supports current_goals_markers
  1267 variable for marking begin of proof, end of proof, start of goal; the
  1268 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1269 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1270 for example;
  1271 
  1272 
  1273 
  1274 New in Isabelle98 (January 1998)
  1275 --------------------------------
  1276 
  1277 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1278 
  1279 * changed lexical syntax of terms / types: dots made part of long
  1280 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1281 
  1282 * simpset (and claset) reference variable replaced by functions
  1283 simpset / simpset_ref;
  1284 
  1285 * no longer supports theory aliases (via merge) and non-trivial
  1286 implicit merge of thms' signatures;
  1287 
  1288 * most internal names of constants changed due to qualified names;
  1289 
  1290 * changed Pure/Sequence interface (see Pure/seq.ML);
  1291 
  1292 
  1293 *** General Changes ***
  1294 
  1295 * hierachically structured name spaces (for consts, types, axms, thms
  1296 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1297 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1298 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1299 long_names for fully qualified output names; NOTE: ML programs
  1300 (special tactics, packages etc.) referring to internal names may have
  1301 to be adapted to cope with fully qualified names; in case of severe
  1302 backward campatibility problems try setting 'global_names' at compile
  1303 time to have enrything declared within a flat name space; one may also
  1304 fine tune name declarations in theories via the 'global' and 'local'
  1305 section;
  1306 
  1307 * reimplemented the implicit simpset and claset using the new anytype
  1308 data filed in signatures; references simpset:simpset ref etc. are
  1309 replaced by functions simpset:unit->simpset and
  1310 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1311 to patch your ML files accordingly;
  1312 
  1313 * HTML output now includes theory graph data for display with Java
  1314 applet or isatool browser; data generated automatically via isatool
  1315 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1316 
  1317 * defs may now be conditional; improved rewrite_goals_tac to handle
  1318 conditional equations;
  1319 
  1320 * defs now admits additional type arguments, using TYPE('a) syntax;
  1321 
  1322 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1323 creates a new theory node; implicit merge of thms' signatures is
  1324 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1325 transfer:theory->thm->thm in (rare) cases;
  1326 
  1327 * improved handling of draft signatures / theories; draft thms (and
  1328 ctyps, cterms) are automatically promoted to real ones;
  1329 
  1330 * slightly changed interfaces for oracles: admit many per theory, named
  1331 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1332 
  1333 * print_goals: optional output of const types (set show_consts and
  1334 show_types);
  1335 
  1336 * improved output of warnings (###) and errors (***);
  1337 
  1338 * subgoal_tac displays a warning if the new subgoal has type variables;
  1339 
  1340 * removed old README and Makefiles;
  1341 
  1342 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1343 
  1344 * removed obsolete init_pps and init_database;
  1345 
  1346 * deleted the obsolete tactical STATE, which was declared by
  1347     fun STATE tacfun st = tacfun st st;
  1348 
  1349 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1350 (which abbreviates $HOME);
  1351 
  1352 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1353 use isatool fixseq to adapt your ML programs (this works for fully
  1354 qualified references to the Sequence structure only!);
  1355 
  1356 * use_thy no longer requires writable current directory; it always
  1357 reloads .ML *and* .thy file, if either one is out of date;
  1358 
  1359 
  1360 *** Classical Reasoner ***
  1361 
  1362 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1363 tactics that use classical reasoning to simplify a subgoal without
  1364 splitting it into several subgoals;
  1365 
  1366 * Safe_tac: like safe_tac but uses the default claset;
  1367 
  1368 
  1369 *** Simplifier ***
  1370 
  1371 * added simplification meta rules:
  1372     (asm_)(full_)simplify: simpset -> thm -> thm;
  1373 
  1374 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1375 logics (again);
  1376 
  1377 * added prems argument to simplification procedures;
  1378 
  1379 * HOL, FOL, ZF: added infix function `addsplits':
  1380   instead of `<simpset> setloop (split_tac <thms>)'
  1381   you can simply write `<simpset> addsplits <thms>'
  1382 
  1383 
  1384 *** Syntax ***
  1385 
  1386 * TYPE('a) syntax for type reflection terms;
  1387 
  1388 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1389 
  1390 * pretty printer: changed order of mixfix annotation preference (again!);
  1391 
  1392 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1393 
  1394 
  1395 *** HOL ***
  1396 
  1397 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1398   with `addloop' of the simplifier to faciliate case splitting in premises.
  1399 
  1400 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1401 
  1402 * HOL/Auth: new protocol proofs including some for the Internet
  1403   protocol TLS;
  1404 
  1405 * HOL/Map: new theory of `maps' a la VDM;
  1406 
  1407 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1408 cancelling out common nat summands from =, <, <= (in)equalities, or
  1409 differences; simplification procedures nat_cancel_factor for
  1410 cancelling common factor from =, <, <= (in)equalities over natural
  1411 sums; nat_cancel contains both kinds of procedures, it is installed by
  1412 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1413 
  1414 * HOL/simplifier: terms of the form
  1415   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1416   are rewritten to
  1417   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1418   and those of the form
  1419   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1420   are rewritten to
  1421   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1422 
  1423 * HOL/datatype
  1424   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1425 
  1426   P(t_case f1 ... fn x) =
  1427      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1428         ...
  1429        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1430      )
  1431 
  1432   and a theorem `split_t_case_asm' of the form
  1433 
  1434   P(t_case f1 ... fn x) =
  1435     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1436         ...
  1437        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1438      )
  1439   which can be added to a simpset via `addsplits'. The existing theorems
  1440   expand_list_case and expand_option_case have been renamed to
  1441   split_list_case and split_option_case.
  1442 
  1443 * HOL/Arithmetic:
  1444   - `pred n' is automatically converted to `n-1'.
  1445     Users are strongly encouraged not to use `pred' any longer,
  1446     because it will disappear altogether at some point.
  1447   - Users are strongly encouraged to write "0 < n" rather than
  1448     "n ~= 0". Theorems and proof tools have been modified towards this
  1449     `standard'.
  1450 
  1451 * HOL/Lists:
  1452   the function "set_of_list" has been renamed "set" (and its theorems too);
  1453   the function "nth" now takes its arguments in the reverse order and
  1454   has acquired the infix notation "!" as in "xs!n".
  1455 
  1456 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1457 
  1458 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1459   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1460 
  1461 * HOL/record: extensible records with schematic structural subtyping
  1462 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1463 still lacks various theorems and concrete record syntax;
  1464 
  1465 
  1466 *** HOLCF ***
  1467 
  1468 * removed "axioms" and "generated by" sections;
  1469 
  1470 * replaced "ops" section by extended "consts" section, which is capable of
  1471   handling the continuous function space "->" directly;
  1472 
  1473 * domain package:
  1474   . proves theorems immediately and stores them in the theory,
  1475   . creates hierachical name space,
  1476   . now uses normal mixfix annotations (instead of cinfix...),
  1477   . minor changes to some names and values (for consistency),
  1478   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1479   . separator between mutual domain defs: changed "," to "and",
  1480   . improved handling of sort constraints;  now they have to
  1481     appear on the left-hand side of the equations only;
  1482 
  1483 * fixed LAM <x,y,zs>.b syntax;
  1484 
  1485 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1486 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1487 
  1488 
  1489 *** FOL and ZF ***
  1490 
  1491 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1492   with `addloop' of the simplifier to faciliate case splitting in premises.
  1493 
  1494 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1495 in HOL, they strip ALL and --> from proved theorems;
  1496 
  1497 
  1498 
  1499 New in Isabelle94-8 (May 1997)
  1500 ------------------------------
  1501 
  1502 *** General Changes ***
  1503 
  1504 * new utilities to build / run / maintain Isabelle etc. (in parts
  1505 still somewhat experimental); old Makefiles etc. still functional;
  1506 
  1507 * new 'Isabelle System Manual';
  1508 
  1509 * INSTALL text, together with ./configure and ./build scripts;
  1510 
  1511 * reimplemented type inference for greater efficiency, better error
  1512 messages and clean internal interface;
  1513 
  1514 * prlim command for dealing with lots of subgoals (an easier way of
  1515 setting goals_limit);
  1516 
  1517 
  1518 *** Syntax ***
  1519 
  1520 * supports alternative (named) syntax tables (parser and pretty
  1521 printer); internal interface is provided by add_modesyntax(_i);
  1522 
  1523 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1524 be used in conjunction with the Isabelle symbol font; uses the
  1525 "symbols" syntax table;
  1526 
  1527 * added token_translation interface (may translate name tokens in
  1528 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1529 the current print_mode); IMPORTANT: user print translation functions
  1530 are responsible for marking newly introduced bounds
  1531 (Syntax.mark_boundT);
  1532 
  1533 * token translations for modes "xterm" and "xterm_color" that display
  1534 names in bold, underline etc. or colors (which requires a color
  1535 version of xterm);
  1536 
  1537 * infixes may now be declared with names independent of their syntax;
  1538 
  1539 * added typed_print_translation (like print_translation, but may
  1540 access type of constant);
  1541 
  1542 
  1543 *** Classical Reasoner ***
  1544 
  1545 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1546 some limitations.  Blast_tac...
  1547   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1548   + ignores elimination rules that don't have the correct format
  1549         (the conclusion MUST be a formula variable)
  1550   + ignores types, which can make HOL proofs fail
  1551   + rules must not require higher-order unification, e.g. apply_type in ZF
  1552     [message "Function Var's argument not a bound variable" relates to this]
  1553   + its proof strategy is more general but can actually be slower
  1554 
  1555 * substitution with equality assumptions no longer permutes other
  1556 assumptions;
  1557 
  1558 * minor changes in semantics of addafter (now called addaltern); renamed
  1559 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1560 (and access functions for it);
  1561 
  1562 * improved combination of classical reasoner and simplifier:
  1563   + functions for handling clasimpsets
  1564   + improvement of addss: now the simplifier is called _after_ the
  1565     safe steps.
  1566   + safe variant of addss called addSss: uses safe simplifications
  1567     _during_ the safe steps. It is more complete as it allows multiple
  1568     instantiations of unknowns (e.g. with slow_tac).
  1569 
  1570 *** Simplifier ***
  1571 
  1572 * added interface for simplification procedures (functions that
  1573 produce *proven* rewrite rules on the fly, depending on current
  1574 redex);
  1575 
  1576 * ordering on terms as parameter (used for ordered rewriting);
  1577 
  1578 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1579 
  1580 * the solver is now split into a safe and an unsafe part.
  1581 This should be invisible for the normal user, except that the
  1582 functions setsolver and addsolver have been renamed to setSolver and
  1583 addSolver; added safe_asm_full_simp_tac;
  1584 
  1585 
  1586 *** HOL ***
  1587 
  1588 * a generic induction tactic `induct_tac' which works for all datatypes and
  1589 also for type `nat';
  1590 
  1591 * a generic case distinction tactic `exhaust_tac' which works for all
  1592 datatypes and also for type `nat';
  1593 
  1594 * each datatype comes with a function `size';
  1595 
  1596 * patterns in case expressions allow tuple patterns as arguments to
  1597 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1598 
  1599 * primrec now also works with type nat;
  1600 
  1601 * recdef: a new declaration form, allows general recursive functions to be
  1602 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1603 
  1604 * the constant for negation has been renamed from "not" to "Not" to
  1605 harmonize with FOL, ZF, LK, etc.;
  1606 
  1607 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1608 infinite lists;
  1609 
  1610 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1611 
  1612 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1613 problems in commutative rings, using axiomatic type classes for + and *;
  1614 
  1615 * more examples in HOL/MiniML and HOL/Auth;
  1616 
  1617 * more default rewrite rules for quantifiers, union/intersection;
  1618 
  1619 * a new constant `arbitrary == @x.False';
  1620 
  1621 * HOLCF/IOA replaces old HOL/IOA;
  1622 
  1623 * HOLCF changes: derived all rules and arities
  1624   + axiomatic type classes instead of classes
  1625   + typedef instead of faking type definitions
  1626   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1627   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1628   + eliminated the types void, one, tr
  1629   + use unit lift and bool lift (with translations) instead of one and tr
  1630   + eliminated blift from Lift3.thy (use Def instead of blift)
  1631   all eliminated rules are derived as theorems --> no visible changes ;
  1632 
  1633 
  1634 *** ZF ***
  1635 
  1636 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1637 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1638 as ZF_cs addSIs [equalityI];
  1639 
  1640 
  1641 
  1642 New in Isabelle94-7 (November 96)
  1643 ---------------------------------
  1644 
  1645 * allowing negative levels (as offsets) in prlev and choplev;
  1646 
  1647 * super-linear speedup for large simplifications;
  1648 
  1649 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1650 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1651 FAIL); can suppress it using the command Delsimps (ex_simps @
  1652 all_simps); De Morgan laws are also now included, by default;
  1653 
  1654 * improved printing of ==>  :  ~:
  1655 
  1656 * new object-logic "Sequents" adds linear logic, while replacing LK
  1657 and Modal (thanks to Sara Kalvala);
  1658 
  1659 * HOL/Auth: correctness proofs for authentication protocols;
  1660 
  1661 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1662 examples on HOL/Auth);
  1663 
  1664 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1665 the rewriter and classical reasoner simultaneously;
  1666 
  1667 * function uresult no longer returns theorems in "standard" format;
  1668 regain previous version by: val uresult = standard o uresult;
  1669 
  1670 
  1671 
  1672 New in Isabelle94-6
  1673 -------------------
  1674 
  1675 * oracles -- these establish an interface between Isabelle and trusted
  1676 external reasoners, which may deliver results as theorems;
  1677 
  1678 * proof objects (in particular record all uses of oracles);
  1679 
  1680 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1681 
  1682 * "constdefs" section in theory files;
  1683 
  1684 * "primrec" section (HOL) no longer requires names;
  1685 
  1686 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1687 
  1688 
  1689 
  1690 New in Isabelle94-5
  1691 -------------------
  1692 
  1693 * reduced space requirements;
  1694 
  1695 * automatic HTML generation from theories;
  1696 
  1697 * theory files no longer require "..." (quotes) around most types;
  1698 
  1699 * new examples, including two proofs of the Church-Rosser theorem;
  1700 
  1701 * non-curried (1994) version of HOL is no longer distributed;
  1702 
  1703 
  1704 
  1705 New in Isabelle94-4
  1706 -------------------
  1707 
  1708 * greatly reduced space requirements;
  1709 
  1710 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1711 
  1712 * searchable theorem database (see the section "Retrieving theorems" on
  1713 page 8 of the Reference Manual);
  1714 
  1715 * new examples, including Grabczewski's monumental case study of the
  1716 Axiom of Choice;
  1717 
  1718 * The previous version of HOL renamed to Old_HOL;
  1719 
  1720 * The new version of HOL (previously called CHOL) uses a curried syntax
  1721 for functions.  Application looks like f a b instead of f(a,b);
  1722 
  1723 * Mutually recursive inductive definitions finally work in HOL;
  1724 
  1725 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1726 translates to the operator "split";
  1727 
  1728 
  1729 
  1730 New in Isabelle94-3
  1731 -------------------
  1732 
  1733 * new infix operator, addss, allowing the classical reasoner to
  1734 perform simplification at each step of its search.  Example:
  1735         fast_tac (cs addss ss)
  1736 
  1737 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1738 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1739 look like (a,b) instead of <a,b>;
  1740 
  1741 * PLEASE NOTE: CHOL will eventually replace HOL!
  1742 
  1743 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1744 It translates to the operator "split".  A new theory of integers is available;
  1745 
  1746 * In ZF, integer numerals now denote two's-complement binary integers.
  1747 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1748 
  1749 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1750 of the Axiom of Choice;
  1751 
  1752 
  1753 
  1754 New in Isabelle94-2
  1755 -------------------
  1756 
  1757 * Significantly faster resolution;
  1758 
  1759 * the different sections in a .thy file can now be mixed and repeated
  1760 freely;
  1761 
  1762 * Database of theorems for FOL, HOL and ZF.  New
  1763 commands including qed, qed_goal and bind_thm store theorems in the database.
  1764 
  1765 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1766 a given theory (thms_of), or find out what theory a theorem was proved in
  1767 (theory_of_thm);
  1768 
  1769 * Bugs fixed in the inductive definition and datatype packages;
  1770 
  1771 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1772 and HOL_dup_cs obsolete;
  1773 
  1774 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1775 have been removed;
  1776 
  1777 * Simpler definition of function space in ZF;
  1778 
  1779 * new results about cardinal and ordinal arithmetic in ZF;
  1780 
  1781 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1782 types;
  1783 
  1784 
  1785 $Id$