NEWS
author oheimb
Wed Feb 21 12:07:00 2001 +0100 (2001-02-21)
changeset 11172 3c82b641b642
parent 11169 98c2f741e32b
child 11181 d04f57b91166
permissions -rw-r--r--
added split_conv_tac (also to claset()) as an optimization
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 * HOL: added safe wrapper "split_conv_tac" to claset. EXISTING PROOFS MAY FAIL
     5 
     6 * HOL: made split_all_tac safe. EXISTING PROOFS MAY FAIL OR LOOP, so in this
     7   (rare) case use   delSWrapper "split_all_tac" addSbefore 
     8                     ("unsafe_split_all_tac", unsafe_split_all_tac)
     9 
    10 
    11 New in Isabelle99-2 (February 2001)
    12 -----------------------------------
    13 
    14 *** Overview of INCOMPATIBILITIES ***
    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 be 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: more robust selection of calculational rules;
   100 
   101 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   102 rule (as well as the assumption rule);
   103 
   104 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   105 lemmas, using the graph browser tool;
   106 
   107 * Pure: predict failure of "show" in interactive mode;
   108 
   109 * Pure: 'thms_containing' now takes actual terms as arguments;
   110 
   111 * HOL: improved method 'induct' --- now handles non-atomic goals
   112 (potential INCOMPATIBILITY); tuned error handling;
   113 
   114 * HOL: cases and induct rules now provide explicit hints about the
   115 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   116 any remaining facts are inserted into the goal verbatim;
   117 
   118 * HOL: local contexts (aka cases) may now contain term bindings as
   119 well; the 'cases' and 'induct' methods new provide a ?case binding for
   120 the result to be shown in each case;
   121 
   122 * HOL: added 'recdef_tc' command;
   123 
   124 * isatool convert assists in eliminating legacy ML scripts;
   125 
   126 
   127 *** HOL ***
   128 
   129 * HOL/Library: a collection of generic theories to be used together
   130 with main HOL; the theory loader path already includes this directory
   131 by default; the following existing theories have been moved here:
   132 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   133 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   134 
   135 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   136 modelling and verification task performed in Isabelle/HOL +
   137 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   138 
   139 * HOL/Algebra: special summation operator SUM no longer exists, it has
   140 been replaced by setsum; infix 'assoc' now has priority 50 (like
   141 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   142 'domain', this makes the theory consistent with mathematical
   143 literature;
   144 
   145 * HOL basics: added overloaded operations "inverse" and "divide"
   146 (infix "/"), syntax for generic "abs" operation, generic summation
   147 operator \<Sum>;
   148 
   149 * HOL/typedef: simplified package, provide more useful rules (see also
   150 HOL/subset.thy);
   151 
   152 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   153 now expressed as a proper nested rule (old-style tactic scripts may
   154 require atomize_strip_tac to cope with non-atomic premises);
   155 
   156 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   157 to "split_conv" (old name still available for compatibility);
   158 
   159 * HOL: improved concrete syntax for strings (e.g. allows translation
   160 rules with string literals);
   161 
   162 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   163 and Fleuriot's mechanization of analysis;
   164 
   165 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   166 
   167 
   168 *** CTT ***
   169 
   170 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   171 "lam" is displayed as TWO lambda-symbols
   172 
   173 * CTT: theory Main now available, containing everything (that is, Bool
   174 and Arith);
   175 
   176 
   177 *** General ***
   178 
   179 * Pure: the Simplifier has been implemented properly as a derived rule
   180 outside of the actual kernel (at last!); the overall performance
   181 penalty in practical applications is about 50%, while reliability of
   182 the Isabelle inference kernel has been greatly improved;
   183 
   184 * print modes "brackets" and "no_brackets" control output of nested =>
   185 (types) and ==> (props); the default behaviour is "brackets";
   186 
   187 * Provers: fast_tac (and friends) now handle actual object-logic rules
   188 as assumptions as well;
   189 
   190 * system: support Poly/ML 4.0;
   191 
   192 * system: isatool install handles KDE version 1 or 2;
   193 
   194 
   195 
   196 New in Isabelle99-1 (October 2000)
   197 ----------------------------------
   198 
   199 *** Overview of INCOMPATIBILITIES ***
   200 
   201 * HOL: simplification of natural numbers is much changed; to partly
   202 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   203 issue the following ML commands:
   204 
   205   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   206   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   207 
   208 * HOL: simplification no longer dives into case-expressions; this is
   209 controlled by "t.weak_case_cong" for each datatype t;
   210 
   211 * HOL: nat_less_induct renamed to less_induct;
   212 
   213 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   214 fixsome to patch .thy and .ML sources automatically;
   215 
   216   select_equality  -> some_equality
   217   select_eq_Ex     -> some_eq_ex
   218   selectI2EX       -> someI2_ex
   219   selectI2         -> someI2
   220   selectI          -> someI
   221   select1_equality -> some1_equality
   222   Eps_sym_eq       -> some_sym_eq_trivial
   223   Eps_eq           -> some_eq_trivial
   224 
   225 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   226 
   227 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   228 instead);
   229 
   230 * HOL: the recursion equations generated by 'recdef' are now called
   231 f.simps instead of f.rules;
   232 
   233 * HOL: qed_spec_mp now also handles bounded ALL as well;
   234 
   235 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   236 sometimes be needed;
   237 
   238 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   239 
   240 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   241 
   242 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   243 product is now "<*>" instead of "Times"; the lexicographic product is
   244 now "<*lex*>" instead of "**";
   245 
   246 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   247 of main HOL, but was unused); better use HOL's datatype package;
   248 
   249 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   250 the old syntax may be recovered as follows:
   251 
   252   syntax (symbols)
   253     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   254       (infixl "\\<oplus>" 100)
   255 
   256 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   257 
   258 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   259 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   260 internally;
   261 
   262 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   263 changed from A/r to A//r;
   264 
   265 * ZF: new treatment of arithmetic (nat & int) may break some old
   266 proofs;
   267 
   268 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   269 rulify -> rule_format, elimify -> elim_format, ...);
   270 
   271 * Isar/Provers: intro/elim/dest attributes changed; renamed
   272 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   273 should have to change intro!! to intro? only); replaced "delrule" by
   274 "rule del";
   275 
   276 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   277 
   278 * Provers: strengthened force_tac by using new first_best_tac;
   279 
   280 * LaTeX document preparation: several changes of isabelle.sty (see
   281 lib/texinputs);
   282 
   283 
   284 *** Document preparation ***
   285 
   286 * formal comments (text blocks etc.) in new-style theories may now
   287 contain antiquotations of thm/prop/term/typ/text to be presented
   288 according to latex print mode; concrete syntax is like this:
   289 @{term[show_types] "f(x) = a + x"};
   290 
   291 * isatool mkdir provides easy setup of Isabelle session directories,
   292 including proper document sources;
   293 
   294 * generated LaTeX sources are now deleted after successful run
   295 (isatool document -c); may retain a copy somewhere else via -D option
   296 of isatool usedir;
   297 
   298 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   299 style files, achieving self-contained LaTeX sources and simplifying
   300 LaTeX debugging;
   301 
   302 * old-style theories now produce (crude) LaTeX output as well;
   303 
   304 * browser info session directories are now self-contained (may be put
   305 on WWW server seperately); improved graphs of nested sessions; removed
   306 graph for 'all sessions';
   307 
   308 * several improvements in isabelle style files; \isabellestyle{it}
   309 produces fake math mode output; \isamarkupheader is now \section by
   310 default; see lib/texinputs/isabelle.sty etc.;
   311 
   312 
   313 *** Isar ***
   314 
   315 * Isar/Pure: local results and corresponding term bindings are now
   316 subject to Hindley-Milner polymorphism (similar to ML); this
   317 accommodates incremental type-inference very nicely;
   318 
   319 * Isar/Pure: new derived language element 'obtain' supports
   320 generalized existence reasoning;
   321 
   322 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   323 support accumulation of results, without applying any rules yet;
   324 useful to collect intermediate results without explicit name
   325 references, and for use with transitivity rules with more than 2
   326 premises;
   327 
   328 * Isar/Pure: scalable support for case-analysis type proofs: new
   329 'case' language element refers to local contexts symbolically, as
   330 produced by certain proof methods; internally, case names are attached
   331 to theorems as "tags";
   332 
   333 * Isar/Pure: theory command 'hide' removes declarations from
   334 class/type/const name spaces;
   335 
   336 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   337 indicate potential overloading;
   338 
   339 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   340 
   341 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   342 "{a,b,c}" instead of {a,b,c};
   343 
   344 * Isar/Pure now provides its own version of intro/elim/dest
   345 attributes; useful for building new logics, but beware of confusion
   346 with the version in Provers/classical;
   347 
   348 * Isar/Pure: the local context of (non-atomic) goals is provided via
   349 case name 'antecedent';
   350 
   351 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   352 to the current context is now done automatically);
   353 
   354 * Isar/Pure: theory command 'method_setup' provides a simple interface
   355 for definining proof methods in ML;
   356 
   357 * Isar/Provers: intro/elim/dest attributes changed; renamed
   358 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   359 most cases, one should have to change intro!! to intro? only);
   360 replaced "delrule" by "rule del";
   361 
   362 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   363 'symmetric' attribute (the latter supercedes [RS sym]);
   364 
   365 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   366 method modifier); 'simp' method: 'only:' modifier removes loopers as
   367 well (including splits);
   368 
   369 * Isar/Provers: Simplifier and Classical methods now support all kind
   370 of modifiers used in the past, including 'cong', 'iff', etc.
   371 
   372 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   373 of Simplifier and Classical reasoner);
   374 
   375 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   376 now support named cases; major packages (inductive, datatype, primrec,
   377 recdef) support case names and properly name parameters;
   378 
   379 * Isar/HOL: new transitivity rules for substitution in inequalities --
   380 monotonicity conditions are extracted to be proven at end of
   381 calculations;
   382 
   383 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   384 method anyway;
   385 
   386 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   387 split_if split_if_asm; datatype package provides theorems foo.splits =
   388 foo.split foo.split_asm for each datatype;
   389 
   390 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   391 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   392 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   393 use "(cases (simplified))" method in proper proof texts);
   394 
   395 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   396 
   397 * Isar: names of theorems etc. may be natural numbers as well;
   398 
   399 * Isar: 'pr' command: optional arguments for goals_limit and
   400 ProofContext.prems_limit; no longer prints theory contexts, but only
   401 proof states;
   402 
   403 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   404 additional print modes to be specified; e.g. "pr(latex)" will print
   405 proof state according to the Isabelle LaTeX style;
   406 
   407 * Isar: improved support for emulating tactic scripts, including proof
   408 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   409 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   410 (for HOL datatypes);
   411 
   412 * Isar: simplified (more robust) goal selection of proof methods: 1st
   413 goal, all goals, or explicit goal specifier (tactic emulation); thus
   414 'proof method scripts' have to be in depth-first order;
   415 
   416 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   417 
   418 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   419 should instead use individual commands for printing items
   420 (print_commands, print_methods etc.);
   421 
   422 * Isar: added 'nothing' --- the empty list of theorems;
   423 
   424 
   425 *** HOL ***
   426 
   427 * HOL/MicroJava: formalization of a fragment of Java, together with a
   428 corresponding virtual machine and a specification of its bytecode
   429 verifier and a lightweight bytecode verifier, including proofs of
   430 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   431 Cornelia Pusch (see also the homepage of project Bali at
   432 http://isabelle.in.tum.de/Bali/);
   433 
   434 * HOL/Algebra: new theory of rings and univariate polynomials, by
   435 Clemens Ballarin;
   436 
   437 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   438 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   439 Rasmussen;
   440 
   441 * HOL/Lattice: fundamental concepts of lattice theory and order
   442 structures, including duals, properties of bounds versus algebraic
   443 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   444 Theorem for complete lattices etc.; may also serve as a demonstration
   445 for abstract algebraic reasoning using axiomatic type classes, and
   446 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   447 
   448 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   449 von Oheimb;
   450 
   451 * HOL/IMPP: extension of IMP with local variables and mutually
   452 recursive procedures, by David von Oheimb;
   453 
   454 * HOL/Lambda: converted into new-style theory and document;
   455 
   456 * HOL/ex/Multiquote: example of multiple nested quotations and
   457 anti-quotations -- basically a generalized version of de-Bruijn
   458 representation; very useful in avoiding lifting of operations;
   459 
   460 * HOL/record: added general record equality rule to simpset; fixed
   461 select-update simplification procedure to handle extended records as
   462 well; admit "r" as field name;
   463 
   464 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   465 other numeric types and also as the identity of groups, rings, etc.;
   466 
   467 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   468 Types nat and int belong to this axclass;
   469 
   470 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   471    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   472    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   473   two terms #m*u and #n*u are replaced by #(m+n)*u
   474     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   475   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   476     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   477 
   478 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   479 powerful prover for predicate logic but knows nothing of clasets; see
   480 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   481 
   482 * HOL: new version of "case_tac" subsumes both boolean case split and
   483 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   484 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   485 
   486 * HOL: simplification no longer dives into case-expressions: only the
   487 selector expression is simplified, but not the remaining arms; to
   488 enable full simplification of case-expressions for datatype t, you may
   489 remove t.weak_case_cong from the simpset, either globally (Delcongs
   490 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   491 
   492 * HOL/recdef: the recursion equations generated by 'recdef' for
   493 function 'f' are now called f.simps instead of f.rules; if all
   494 termination conditions are proved automatically, these simplification
   495 rules are added to the simpset, as in primrec; rules may be named
   496 individually as well, resulting in a separate list of theorems for
   497 each equation;
   498 
   499 * HOL/While is a new theory that provides a while-combinator. It
   500 permits the definition of tail-recursive functions without the
   501 provision of a termination measure. The latter is necessary once the
   502 invariant proof rule for while is applied.
   503 
   504 * HOL: new (overloaded) notation for the set of elements below/above
   505 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   506 
   507 * HOL: theorems impI, allI, ballI bound as "strip";
   508 
   509 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   510 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   511 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   512 
   513 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   514 
   515 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   516 main HOL, but was unused);
   517 
   518 * HOL: fewer consts declared as global (e.g. have to refer to
   519 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   520 
   521 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   522 in case of overlap with user translations (e.g. judgements over
   523 tuples); (note that the underlying logical represenation is still
   524 bogus);
   525 
   526 
   527 *** ZF ***
   528 
   529 * ZF: simplification automatically cancels common terms in arithmetic
   530 expressions over nat and int;
   531 
   532 * ZF: new treatment of nat to minimize type-checking: all operators
   533 coerce their operands to a natural number using the function natify,
   534 making the algebraic laws unconditional;
   535 
   536 * ZF: as above, for int: operators coerce their operands to an integer
   537 using the function intify;
   538 
   539 * ZF: the integer library now contains many of the usual laws for the
   540 orderings, including $<=, and monotonicity laws for $+ and $*;
   541 
   542 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   543 simplification;
   544 
   545 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   546 to the simplifier and classical reasoner simultaneously;
   547 
   548 
   549 *** General ***
   550 
   551 * Provers: blast_tac now handles actual object-logic rules as
   552 assumptions; note that auto_tac uses blast_tac internally as well;
   553 
   554 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   555 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   556 
   557 * Provers: delrules now handles destruct rules as well (no longer need
   558 explicit make_elim);
   559 
   560 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   561   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   562 use instead the strong form,
   563   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   564 in HOL, FOL and ZF the function cla_make_elim will create such rules
   565 from destruct-rules;
   566 
   567 * Provers: Simplifier.easy_setup provides a fast path to basic
   568 Simplifier setup for new object-logics;
   569 
   570 * Pure: AST translation rules no longer require constant head on LHS;
   571 
   572 * Pure: improved name spaces: ambiguous output is qualified; support
   573 for hiding of names;
   574 
   575 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   576 XSYMBOL_HOME; no longer need to do manual configuration in most
   577 situations;
   578 
   579 * system: compression of ML heaps images may now be controlled via -c
   580 option of isabelle and isatool usedir (currently only observed by
   581 Poly/ML);
   582 
   583 * system: isatool installfonts may handle X-Symbol fonts as well (very
   584 useful for remote X11);
   585 
   586 * system: provide TAGS file for Isabelle sources;
   587 
   588 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   589 order;
   590 
   591 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   592 timing flag supersedes proof_timing and Toplevel.trace;
   593 
   594 * ML: new combinators |>> and |>>> for incremental transformations
   595 with secondary results (e.g. certain theory extensions):
   596 
   597 * ML: PureThy.add_defs gets additional argument to indicate potential
   598 overloading (usually false);
   599 
   600 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   601 results;
   602 
   603 
   604 
   605 New in Isabelle99 (October 1999)
   606 --------------------------------
   607 
   608 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   609 
   610 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   611 are no longer simplified.  (This allows the simplifier to unfold recursive
   612 functional programs.)  To restore the old behaviour, declare
   613 
   614     Delcongs [if_weak_cong];
   615 
   616 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   617 complement;
   618 
   619 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   620 
   621 * HOL/datatype: mutual_induct_tac no longer exists --
   622   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   623 
   624 * HOL/typedef: fixed type inference for representing set; type
   625 arguments now have to occur explicitly on the rhs as type constraints;
   626 
   627 * ZF: The con_defs part of an inductive definition may no longer refer
   628 to constants declared in the same theory;
   629 
   630 * HOL, ZF: the function mk_cases, generated by the inductive
   631 definition package, has lost an argument.  To simplify its result, it
   632 uses the default simpset instead of a supplied list of theorems.
   633 
   634 * HOL/List: the constructors of type list are now Nil and Cons;
   635 
   636 * Simplifier: the type of the infix ML functions
   637         setSSolver addSSolver setSolver addSolver
   638 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   639 for packaging solvers. A solver is created via
   640         mk_solver: string -> (thm list -> int -> tactic) -> solver
   641 where the string argument is only a comment.
   642 
   643 
   644 *** Proof tools ***
   645 
   646 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   647 decision procedure for linear arithmetic. Currently it is used for
   648 types `nat', `int', and `real' in HOL (see below); it can, should and
   649 will be instantiated for other types and logics as well.
   650 
   651 * The simplifier now accepts rewrite rules with flexible heads, eg
   652      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   653   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   654   matching.
   655 
   656 
   657 *** General ***
   658 
   659 * New Isabelle/Isar subsystem provides an alternative to traditional
   660 tactical theorem proving; together with the ProofGeneral/isar user
   661 interface it offers an interactive environment for developing human
   662 readable proof documents (Isar == Intelligible semi-automated
   663 reasoning); for further information see isatool doc isar-ref,
   664 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   665 
   666 * improved and simplified presentation of theories: better HTML markup
   667 (including colors), graph views in several sizes; isatool usedir now
   668 provides a proper interface for user theories (via -P option); actual
   669 document preparation based on (PDF)LaTeX is available as well (for
   670 new-style theories only); see isatool doc system for more information;
   671 
   672 * native support for Proof General, both for classic Isabelle and
   673 Isabelle/Isar;
   674 
   675 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   676 using the graph browser tool;
   677 
   678 * Isabelle manuals now also available as PDF;
   679 
   680 * theory loader rewritten from scratch (may not be fully
   681 bug-compatible); old loadpath variable has been replaced by show_path,
   682 add_path, del_path, reset_path functions; new operations such as
   683 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   684 isatool doc ref);
   685 
   686 * improved isatool install: option -k creates KDE application icon,
   687 option -p DIR installs standalone binaries;
   688 
   689 * added ML_PLATFORM setting (useful for cross-platform installations);
   690 more robust handling of platform specific ML images for SML/NJ;
   691 
   692 * the settings environment is now statically scoped, i.e. it is never
   693 created again in sub-processes invoked from isabelle, isatool, or
   694 Isabelle;
   695 
   696 * path element specification '~~' refers to '$ISABELLE_HOME';
   697 
   698 * in locales, the "assumes" and "defines" parts may be omitted if
   699 empty;
   700 
   701 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   702 long arrows);
   703 
   704 * new print_mode "HTML";
   705 
   706 * new flag show_tags controls display of tags of theorems (which are
   707 basically just comments that may be attached by some tools);
   708 
   709 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   710 mode and goal output format:
   711 
   712 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   713 244c244
   714 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   715 ---
   716 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   717 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   718 181c181
   719 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   720 ---
   721 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   722 
   723 * function bind_thms stores lists of theorems (cf. bind_thm);
   724 
   725 * new shorthand tactics ftac, eatac, datac, fatac;
   726 
   727 * qed (and friends) now accept "" as result name; in that case the
   728 theorem is not stored, but proper checks and presentation of the
   729 result still apply;
   730 
   731 * theorem database now also indexes constants "Trueprop", "all",
   732 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   733 
   734 
   735 *** HOL ***
   736 
   737 ** HOL arithmetic **
   738 
   739 * There are now decision procedures for linear arithmetic over nat and
   740 int:
   741 
   742 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   743 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   744 are treated as atomic; subformulae not involving type `nat' or `int'
   745 are ignored; quantified subformulae are ignored unless they are
   746 positive universal or negative existential. The tactic has to be
   747 invoked by hand and can be a little bit slow. In particular, the
   748 running time is exponential in the number of occurrences of `min' and
   749 `max', and `-' on `nat'.
   750 
   751 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   752 (negated) (in)equalities among the premises and the conclusion into
   753 account (i.e. no compound formulae) and does not know about `min' and
   754 `max', and `-' on `nat'. It is fast and is used automatically by the
   755 simplifier.
   756 
   757 NB: At the moment, these decision procedures do not cope with mixed
   758 nat/int formulae where the two parts interact, such as `m < n ==>
   759 int(m) < int(n)'.
   760 
   761 * HOL/Numeral provides a generic theory of numerals (encoded
   762 efficiently as bit strings); setup for types nat/int/real is in place;
   763 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   764 int, existing theories and proof scripts may require a few additional
   765 type constraints;
   766 
   767 * integer division and remainder can now be performed on constant
   768 arguments;
   769 
   770 * many properties of integer multiplication, division and remainder
   771 are now available;
   772 
   773 * An interface to the Stanford Validity Checker (SVC) is available through the
   774 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   775 are proved automatically.  SVC must be installed separately, and its results
   776 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   777 invocation of the underlying oracle).  For SVC see
   778   http://verify.stanford.edu/SVC
   779 
   780 * IsaMakefile: the HOL-Real target now builds an actual image;
   781 
   782 
   783 ** HOL misc **
   784 
   785 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   786 (in Isabelle/Isar) -- by Gertrud Bauer;
   787 
   788 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   789 analysis for assembly languages with subtypes;
   790 
   791 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   792 -- avoids syntactic ambiguities and treats state, transition, and
   793 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   794 changed syntax and (many) tactics;
   795 
   796 * HOL/inductive: Now also handles more general introduction rules such
   797   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   798   theorems are now maintained within the theory (maintained via the
   799   "mono" attribute);
   800 
   801 * HOL/datatype: Now also handles arbitrarily branching datatypes
   802   (using function types) such as
   803 
   804   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   805 
   806 * HOL/record: record_simproc (part of the default simpset) takes care
   807 of selectors applied to updated records; record_split_tac is no longer
   808 part of the default claset; update_defs may now be removed from the
   809 simpset in many cases; COMPATIBILITY: old behavior achieved by
   810 
   811   claset_ref () := claset() addSWrapper record_split_wrapper;
   812   Delsimprocs [record_simproc]
   813 
   814 * HOL/typedef: fixed type inference for representing set; type
   815 arguments now have to occur explicitly on the rhs as type constraints;
   816 
   817 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   818 names rather than an ML expression;
   819 
   820 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   821 supplied later.  Program schemes can be defined, such as
   822     "While B C s = (if B s then While B C (C s) else s)"
   823 where the well-founded relation can be chosen after B and C have been given.
   824 
   825 * HOL/List: the constructors of type list are now Nil and Cons;
   826 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   827 course, ML tools referring to List.list.op # etc. have to be adapted;
   828 
   829 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   830 disabled by default; run isabelle with option -m HOL to get back to
   831 the original Gordon/HOL-style output;
   832 
   833 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   834 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   835 
   836 * HOL basic syntax simplified (more orthogonal): all variants of
   837 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   838 Eps operator is provided as well: "SOME x. P[x]";
   839 
   840 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   841 
   842 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   843 thus available for user theories;
   844 
   845 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   846 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   847 time;
   848 
   849 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   850 several times and then mp;
   851 
   852 
   853 *** LK ***
   854 
   855 * the notation <<...>> is now available as a notation for sequences of
   856 formulas;
   857 
   858 * the simplifier is now installed
   859 
   860 * the axiom system has been generalized (thanks to Soren Heilmann)
   861 
   862 * the classical reasoner now has a default rule database
   863 
   864 
   865 *** ZF ***
   866 
   867 * new primrec section allows primitive recursive functions to be given
   868 directly (as in HOL) over datatypes and the natural numbers;
   869 
   870 * new tactics induct_tac and exhaust_tac for induction (or case
   871 analysis) over datatypes and the natural numbers;
   872 
   873 * the datatype declaration of type T now defines the recursor T_rec;
   874 
   875 * simplification automatically does freeness reasoning for datatype
   876 constructors;
   877 
   878 * automatic type-inference, with AddTCs command to insert new
   879 type-checking rules;
   880 
   881 * datatype introduction rules are now added as Safe Introduction rules
   882 to the claset;
   883 
   884 * the syntax "if P then x else y" is now available in addition to
   885 if(P,x,y);
   886 
   887 
   888 *** Internal programming interfaces ***
   889 
   890 * tuned simplifier trace output; new flag debug_simp;
   891 
   892 * structures Vartab / Termtab (instances of TableFun) offer efficient
   893 tables indexed by indexname_ord / term_ord (compatible with aconv);
   894 
   895 * AxClass.axclass_tac lost the theory argument;
   896 
   897 * tuned current_goals_markers semantics: begin / end goal avoids
   898 printing empty lines;
   899 
   900 * removed prs and prs_fn hook, which was broken because it did not
   901 include \n in its semantics, forcing writeln to add one
   902 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   903 string -> unit if you really want to output text without newline;
   904 
   905 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   906 plain output, interface builders may have to enable 'isabelle_font'
   907 mode to get Isabelle font glyphs as before;
   908 
   909 * refined token_translation interface; INCOMPATIBILITY: output length
   910 now of type real instead of int;
   911 
   912 * theory loader actions may be traced via new ThyInfo.add_hook
   913 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   914 your own database of information attached to *whole* theories -- as
   915 opposed to intra-theory data slots offered via TheoryDataFun;
   916 
   917 * proper handling of dangling sort hypotheses (at last!);
   918 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   919 extra sort hypotheses that can be witnessed from the type signature;
   920 the force_strip_shyps flag is gone, any remaining shyps are simply
   921 left in the theorem (with a warning issued by strip_shyps_warning);
   922 
   923 
   924 
   925 New in Isabelle98-1 (October 1998)
   926 ----------------------------------
   927 
   928 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   929 
   930 * several changes of automated proof tools;
   931 
   932 * HOL: major changes to the inductive and datatype packages, including
   933 some minor incompatibilities of theory syntax;
   934 
   935 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   936 called `inj_on';
   937 
   938 * HOL: removed duplicate thms in Arith:
   939   less_imp_add_less  should be replaced by  trans_less_add1
   940   le_imp_add_le      should be replaced by  trans_le_add1
   941 
   942 * HOL: unary minus is now overloaded (new type constraints may be
   943 required);
   944 
   945 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   946 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   947 now taken as an integer constant.
   948 
   949 * Pure: ML function 'theory_of' renamed to 'theory';
   950 
   951 
   952 *** Proof tools ***
   953 
   954 * Simplifier:
   955   1. Asm_full_simp_tac is now more aggressive.
   956      1. It will sometimes reorient premises if that increases their power to
   957         simplify.
   958      2. It does no longer proceed strictly from left to right but may also
   959         rotate premises to achieve further simplification.
   960      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   961      old Asm_full_simp_tac in that it does not rotate premises.
   962   2. The simplifier now knows a little bit about nat-arithmetic.
   963 
   964 * Classical reasoner: wrapper mechanism for the classical reasoner now
   965 allows for selected deletion of wrappers, by introduction of names for
   966 wrapper functionals.  This implies that addbefore, addSbefore,
   967 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   968 and that adding two tactics with the same name overwrites the first
   969 one (emitting a warning).
   970   type wrapper = (int -> tactic) -> (int -> tactic)
   971   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   972   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   973   delWrapper, delSWrapper: claset *  string            -> claset
   974   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   975 
   976 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   977 semantics; addbefore now affects only the unsafe part of step_tac
   978 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   979 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   980 by Force_tac;
   981 
   982 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   983 compWrapper; added safe wrapper (and access functions for it);
   984 
   985 * HOL/split_all_tac is now much faster and fails if there is nothing
   986 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   987 and the names of the automatically generated variables have changed.
   988 split_all_tac has moved within claset() from unsafe wrappers to safe
   989 wrappers, which means that !!-bound variables are split much more
   990 aggressively, and safe_tac and clarify_tac now split such variables.
   991 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   992 Note: the same holds for record_split_tac, which does the job of
   993 split_all_tac for record fields.
   994 
   995 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   996 permanently to the default simpset using Addsplits just like
   997 Addsimps. They can be removed via Delsplits just like
   998 Delsimps. Lower-case versions are also available.
   999 
  1000 * HOL/Simplifier: The rule split_if is now part of the default
  1001 simpset. This means that the simplifier will eliminate all occurrences
  1002 of if-then-else in the conclusion of a goal. To prevent this, you can
  1003 either remove split_if completely from the default simpset by
  1004 `Delsplits [split_if]' or remove it in a specific call of the
  1005 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1006 other case splitting rules to/from the default simpset: every datatype
  1007 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1008 t is the name of the datatype).
  1009 
  1010 * Classical reasoner / Simplifier combination: new force_tac (and
  1011 derivatives Force_tac, force) combines rewriting and classical
  1012 reasoning (and whatever other tools) similarly to auto_tac, but is
  1013 aimed to solve the given subgoal completely.
  1014 
  1015 
  1016 *** General ***
  1017 
  1018 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1019 and `goalw': the theory is no longer needed as an explicit argument -
  1020 the current theory context is used; assumptions are no longer returned
  1021 at the ML-level unless one of them starts with ==> or !!; it is
  1022 recommended to convert to these new commands using isatool fixgoal
  1023 (backup your sources first!);
  1024 
  1025 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1026 the current theory context, and 'theory' to lookup stored theories;
  1027 
  1028 * new theory section 'locale' for declaring constants, assumptions and
  1029 definitions that have local scope;
  1030 
  1031 * new theory section 'nonterminals' for purely syntactic types;
  1032 
  1033 * new theory section 'setup' for generic ML setup functions
  1034 (e.g. package initialization);
  1035 
  1036 * the distribution now includes Isabelle icons: see
  1037 lib/logo/isabelle-{small,tiny}.xpm;
  1038 
  1039 * isatool install - install binaries with absolute references to
  1040 ISABELLE_HOME/bin;
  1041 
  1042 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1043 
  1044 * print mode 'emacs' reserved for Isamode;
  1045 
  1046 * support multiple print (ast) translations per constant name;
  1047 
  1048 * theorems involving oracles are now printed with a suffixed [!];
  1049 
  1050 
  1051 *** HOL ***
  1052 
  1053 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1054 
  1055 * HOL/inductive package reorganized and improved: now supports mutual
  1056 definitions such as
  1057 
  1058   inductive EVEN ODD
  1059     intrs
  1060       null "0 : EVEN"
  1061       oddI "n : EVEN ==> Suc n : ODD"
  1062       evenI "n : ODD ==> Suc n : EVEN"
  1063 
  1064 new theorem list "elims" contains an elimination rule for each of the
  1065 recursive sets; inductive definitions now handle disjunctive premises
  1066 correctly (also ZF);
  1067 
  1068 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1069 "mutual_induct" no longer exists - the induction rule is always
  1070 contained in "induct";
  1071 
  1072 
  1073 * HOL/datatype package re-implemented and greatly improved: now
  1074 supports mutually recursive datatypes such as
  1075 
  1076   datatype
  1077     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1078             | SUM ('a aexp) ('a aexp)
  1079             | DIFF ('a aexp) ('a aexp)
  1080             | NUM 'a
  1081   and
  1082     'a bexp = LESS ('a aexp) ('a aexp)
  1083             | AND ('a bexp) ('a bexp)
  1084             | OR ('a bexp) ('a bexp)
  1085 
  1086 as well as indirectly recursive datatypes such as
  1087 
  1088   datatype
  1089     ('a, 'b) term = Var 'a
  1090                   | App 'b ((('a, 'b) term) list)
  1091 
  1092 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1093 induction on mutually / indirectly recursive datatypes.
  1094 
  1095 Primrec equations are now stored in theory and can be accessed via
  1096 <function_name>.simps.
  1097 
  1098 INCOMPATIBILITIES:
  1099 
  1100   - Theories using datatypes must now have theory Datatype as an
  1101     ancestor.
  1102   - The specific <typename>.induct_tac no longer exists - use the
  1103     generic induct_tac instead.
  1104   - natE has been renamed to nat.exhaust - use exhaust_tac
  1105     instead of res_inst_tac ... natE. Note that the variable
  1106     names in nat.exhaust differ from the names in natE, this
  1107     may cause some "fragile" proofs to fail.
  1108   - The theorems split_<typename>_case and split_<typename>_case_asm
  1109     have been renamed to <typename>.split and <typename>.split_asm.
  1110   - Since default sorts of type variables are now handled correctly,
  1111     some datatype definitions may have to be annotated with explicit
  1112     sort constraints.
  1113   - Primrec definitions no longer require function name and type
  1114     of recursive argument.
  1115 
  1116 Consider using isatool fixdatatype to adapt your theories and proof
  1117 scripts to the new package (backup your sources first!).
  1118 
  1119 
  1120 * HOL/record package: considerably improved implementation; now
  1121 includes concrete syntax for record types, terms, updates; theorems
  1122 for surjective pairing and splitting !!-bound record variables; proof
  1123 support is as follows:
  1124 
  1125   1) standard conversions (selectors or updates applied to record
  1126 constructor terms) are part of the standard simpset;
  1127 
  1128   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1129 made part of standard simpset and claset via addIffs;
  1130 
  1131   3) a tactic for record field splitting (record_split_tac) is part of
  1132 the standard claset (addSWrapper);
  1133 
  1134 To get a better idea about these rules you may retrieve them via
  1135 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1136 the name of your record type.
  1137 
  1138 The split tactic 3) conceptually simplifies by the following rule:
  1139 
  1140   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1141 
  1142 Thus any record variable that is bound by meta-all will automatically
  1143 blow up into some record constructor term, consequently the
  1144 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1145 solve record problems automatically.
  1146 
  1147 
  1148 * reorganized the main HOL image: HOL/Integ and String loaded by
  1149 default; theory Main includes everything;
  1150 
  1151 * automatic simplification of integer sums and comparisons, using cancellation;
  1152 
  1153 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1154 
  1155 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1156 
  1157 * many new identities for unions, intersections, set difference, etc.;
  1158 
  1159 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1160 called split_if, split_split, split_sum_case and split_nat_case (to go
  1161 with add/delsplits);
  1162 
  1163 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1164 (?x::unit) = (); this is made part of the default simpset, which COULD
  1165 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1166 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1167 unit_abs_eta_conv is added in order to counter the effect of
  1168 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1169 %u.f();
  1170 
  1171 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1172 makes more sense);
  1173 
  1174 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1175   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1176   disjointness reasoning but breaking a few old proofs.
  1177 
  1178 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1179 to 'converse' from 'inverse' (for compatibility with ZF and some
  1180 literature);
  1181 
  1182 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1183 the well-founded relation;
  1184 
  1185 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1186     Compl A.  The "Compl" syntax remains available as input syntax for this
  1187     release ONLY.
  1188 
  1189 * HOL/Update: new theory of function updates:
  1190     f(a:=b) == %x. if x=a then b else f x
  1191 may also be iterated as in f(a:=b,c:=d,...);
  1192 
  1193 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1194 
  1195 * HOL/List:
  1196   - new function list_update written xs[i:=v] that updates the i-th
  1197     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1198   - new function `upt' written [i..j(] which generates the list
  1199     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1200     bound write [i..j], which is a shorthand for [i..j+1(].
  1201   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1202 
  1203 * HOL/Arith:
  1204   - removed 'pred' (predecessor) function;
  1205   - generalized some theorems about n-1;
  1206   - many new laws about "div" and "mod";
  1207   - new laws about greatest common divisors (see theory ex/Primes);
  1208 
  1209 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1210 instead of "inverse";
  1211 
  1212 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1213   of the multiset ordering;
  1214 
  1215 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1216   (not included by default);
  1217 
  1218 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1219 
  1220 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1221   programs, i.e. different program variables may have different types.
  1222 
  1223 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1224   [previously, this check worked only if the rewrite rule was unconditional]
  1225   Now rew can involve either definitions or equalities (either == or =).
  1226 
  1227 
  1228 *** ZF ***
  1229 
  1230 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1231   only the theorems proved on ZF.ML;
  1232 
  1233 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1234   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1235   disjointness reasoning but breaking a few old proofs.
  1236 
  1237 * ZF/Update: new theory of function updates
  1238     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1239   may also be iterated as in f(a:=b,c:=d,...);
  1240 
  1241 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1242 
  1243 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1244   [previously, this check worked only if the rewrite rule was unconditional]
  1245   Now rew can involve either definitions or equalities (either == or =).
  1246 
  1247 * case_tac provided for compatibility with HOL
  1248     (like the old excluded_middle_tac, but with subgoals swapped)
  1249 
  1250 
  1251 *** Internal programming interfaces ***
  1252 
  1253 * Pure: several new basic modules made available for general use, see
  1254 also src/Pure/README;
  1255 
  1256 * improved the theory data mechanism to support encapsulation (data
  1257 kind name replaced by private Object.kind, acting as authorization
  1258 key); new type-safe user interface via functor TheoryDataFun; generic
  1259 print_data function becomes basically useless;
  1260 
  1261 * removed global_names compatibility flag -- all theory declarations
  1262 are qualified by default;
  1263 
  1264 * module Pure/Syntax now offers quote / antiquote translation
  1265 functions (useful for Hoare logic etc. with implicit dependencies);
  1266 see HOL/ex/Antiquote for an example use;
  1267 
  1268 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1269 cterm -> thm;
  1270 
  1271 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1272 subgoal;
  1273 
  1274 * Display.print_goals function moved to Locale.print_goals;
  1275 
  1276 * standard print function for goals supports current_goals_markers
  1277 variable for marking begin of proof, end of proof, start of goal; the
  1278 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1279 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1280 for example;
  1281 
  1282 
  1283 
  1284 New in Isabelle98 (January 1998)
  1285 --------------------------------
  1286 
  1287 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1288 
  1289 * changed lexical syntax of terms / types: dots made part of long
  1290 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1291 
  1292 * simpset (and claset) reference variable replaced by functions
  1293 simpset / simpset_ref;
  1294 
  1295 * no longer supports theory aliases (via merge) and non-trivial
  1296 implicit merge of thms' signatures;
  1297 
  1298 * most internal names of constants changed due to qualified names;
  1299 
  1300 * changed Pure/Sequence interface (see Pure/seq.ML);
  1301 
  1302 
  1303 *** General Changes ***
  1304 
  1305 * hierachically structured name spaces (for consts, types, axms, thms
  1306 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1307 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1308 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1309 long_names for fully qualified output names; NOTE: ML programs
  1310 (special tactics, packages etc.) referring to internal names may have
  1311 to be adapted to cope with fully qualified names; in case of severe
  1312 backward campatibility problems try setting 'global_names' at compile
  1313 time to have enrything declared within a flat name space; one may also
  1314 fine tune name declarations in theories via the 'global' and 'local'
  1315 section;
  1316 
  1317 * reimplemented the implicit simpset and claset using the new anytype
  1318 data filed in signatures; references simpset:simpset ref etc. are
  1319 replaced by functions simpset:unit->simpset and
  1320 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1321 to patch your ML files accordingly;
  1322 
  1323 * HTML output now includes theory graph data for display with Java
  1324 applet or isatool browser; data generated automatically via isatool
  1325 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1326 
  1327 * defs may now be conditional; improved rewrite_goals_tac to handle
  1328 conditional equations;
  1329 
  1330 * defs now admits additional type arguments, using TYPE('a) syntax;
  1331 
  1332 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1333 creates a new theory node; implicit merge of thms' signatures is
  1334 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1335 transfer:theory->thm->thm in (rare) cases;
  1336 
  1337 * improved handling of draft signatures / theories; draft thms (and
  1338 ctyps, cterms) are automatically promoted to real ones;
  1339 
  1340 * slightly changed interfaces for oracles: admit many per theory, named
  1341 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1342 
  1343 * print_goals: optional output of const types (set show_consts and
  1344 show_types);
  1345 
  1346 * improved output of warnings (###) and errors (***);
  1347 
  1348 * subgoal_tac displays a warning if the new subgoal has type variables;
  1349 
  1350 * removed old README and Makefiles;
  1351 
  1352 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1353 
  1354 * removed obsolete init_pps and init_database;
  1355 
  1356 * deleted the obsolete tactical STATE, which was declared by
  1357     fun STATE tacfun st = tacfun st st;
  1358 
  1359 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1360 (which abbreviates $HOME);
  1361 
  1362 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1363 use isatool fixseq to adapt your ML programs (this works for fully
  1364 qualified references to the Sequence structure only!);
  1365 
  1366 * use_thy no longer requires writable current directory; it always
  1367 reloads .ML *and* .thy file, if either one is out of date;
  1368 
  1369 
  1370 *** Classical Reasoner ***
  1371 
  1372 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1373 tactics that use classical reasoning to simplify a subgoal without
  1374 splitting it into several subgoals;
  1375 
  1376 * Safe_tac: like safe_tac but uses the default claset;
  1377 
  1378 
  1379 *** Simplifier ***
  1380 
  1381 * added simplification meta rules:
  1382     (asm_)(full_)simplify: simpset -> thm -> thm;
  1383 
  1384 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1385 logics (again);
  1386 
  1387 * added prems argument to simplification procedures;
  1388 
  1389 * HOL, FOL, ZF: added infix function `addsplits':
  1390   instead of `<simpset> setloop (split_tac <thms>)'
  1391   you can simply write `<simpset> addsplits <thms>'
  1392 
  1393 
  1394 *** Syntax ***
  1395 
  1396 * TYPE('a) syntax for type reflection terms;
  1397 
  1398 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1399 
  1400 * pretty printer: changed order of mixfix annotation preference (again!);
  1401 
  1402 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1403 
  1404 
  1405 *** HOL ***
  1406 
  1407 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1408   with `addloop' of the simplifier to faciliate case splitting in premises.
  1409 
  1410 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1411 
  1412 * HOL/Auth: new protocol proofs including some for the Internet
  1413   protocol TLS;
  1414 
  1415 * HOL/Map: new theory of `maps' a la VDM;
  1416 
  1417 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1418 cancelling out common nat summands from =, <, <= (in)equalities, or
  1419 differences; simplification procedures nat_cancel_factor for
  1420 cancelling common factor from =, <, <= (in)equalities over natural
  1421 sums; nat_cancel contains both kinds of procedures, it is installed by
  1422 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1423 
  1424 * HOL/simplifier: terms of the form
  1425   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1426   are rewritten to
  1427   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1428   and those of the form
  1429   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1430   are rewritten to
  1431   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1432 
  1433 * HOL/datatype
  1434   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1435 
  1436   P(t_case f1 ... fn x) =
  1437      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1438         ...
  1439        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1440      )
  1441 
  1442   and a theorem `split_t_case_asm' of the form
  1443 
  1444   P(t_case f1 ... fn x) =
  1445     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1446         ...
  1447        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1448      )
  1449   which can be added to a simpset via `addsplits'. The existing theorems
  1450   expand_list_case and expand_option_case have been renamed to
  1451   split_list_case and split_option_case.
  1452 
  1453 * HOL/Arithmetic:
  1454   - `pred n' is automatically converted to `n-1'.
  1455     Users are strongly encouraged not to use `pred' any longer,
  1456     because it will disappear altogether at some point.
  1457   - Users are strongly encouraged to write "0 < n" rather than
  1458     "n ~= 0". Theorems and proof tools have been modified towards this
  1459     `standard'.
  1460 
  1461 * HOL/Lists:
  1462   the function "set_of_list" has been renamed "set" (and its theorems too);
  1463   the function "nth" now takes its arguments in the reverse order and
  1464   has acquired the infix notation "!" as in "xs!n".
  1465 
  1466 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1467 
  1468 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1469   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1470 
  1471 * HOL/record: extensible records with schematic structural subtyping
  1472 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1473 still lacks various theorems and concrete record syntax;
  1474 
  1475 
  1476 *** HOLCF ***
  1477 
  1478 * removed "axioms" and "generated by" sections;
  1479 
  1480 * replaced "ops" section by extended "consts" section, which is capable of
  1481   handling the continuous function space "->" directly;
  1482 
  1483 * domain package:
  1484   . proves theorems immediately and stores them in the theory,
  1485   . creates hierachical name space,
  1486   . now uses normal mixfix annotations (instead of cinfix...),
  1487   . minor changes to some names and values (for consistency),
  1488   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1489   . separator between mutual domain defs: changed "," to "and",
  1490   . improved handling of sort constraints;  now they have to
  1491     appear on the left-hand side of the equations only;
  1492 
  1493 * fixed LAM <x,y,zs>.b syntax;
  1494 
  1495 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1496 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1497 
  1498 
  1499 *** FOL and ZF ***
  1500 
  1501 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1502   with `addloop' of the simplifier to faciliate case splitting in premises.
  1503 
  1504 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1505 in HOL, they strip ALL and --> from proved theorems;
  1506 
  1507 
  1508 
  1509 New in Isabelle94-8 (May 1997)
  1510 ------------------------------
  1511 
  1512 *** General Changes ***
  1513 
  1514 * new utilities to build / run / maintain Isabelle etc. (in parts
  1515 still somewhat experimental); old Makefiles etc. still functional;
  1516 
  1517 * new 'Isabelle System Manual';
  1518 
  1519 * INSTALL text, together with ./configure and ./build scripts;
  1520 
  1521 * reimplemented type inference for greater efficiency, better error
  1522 messages and clean internal interface;
  1523 
  1524 * prlim command for dealing with lots of subgoals (an easier way of
  1525 setting goals_limit);
  1526 
  1527 
  1528 *** Syntax ***
  1529 
  1530 * supports alternative (named) syntax tables (parser and pretty
  1531 printer); internal interface is provided by add_modesyntax(_i);
  1532 
  1533 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1534 be used in conjunction with the Isabelle symbol font; uses the
  1535 "symbols" syntax table;
  1536 
  1537 * added token_translation interface (may translate name tokens in
  1538 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1539 the current print_mode); IMPORTANT: user print translation functions
  1540 are responsible for marking newly introduced bounds
  1541 (Syntax.mark_boundT);
  1542 
  1543 * token translations for modes "xterm" and "xterm_color" that display
  1544 names in bold, underline etc. or colors (which requires a color
  1545 version of xterm);
  1546 
  1547 * infixes may now be declared with names independent of their syntax;
  1548 
  1549 * added typed_print_translation (like print_translation, but may
  1550 access type of constant);
  1551 
  1552 
  1553 *** Classical Reasoner ***
  1554 
  1555 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1556 some limitations.  Blast_tac...
  1557   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1558   + ignores elimination rules that don't have the correct format
  1559         (the conclusion MUST be a formula variable)
  1560   + ignores types, which can make HOL proofs fail
  1561   + rules must not require higher-order unification, e.g. apply_type in ZF
  1562     [message "Function Var's argument not a bound variable" relates to this]
  1563   + its proof strategy is more general but can actually be slower
  1564 
  1565 * substitution with equality assumptions no longer permutes other
  1566 assumptions;
  1567 
  1568 * minor changes in semantics of addafter (now called addaltern); renamed
  1569 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1570 (and access functions for it);
  1571 
  1572 * improved combination of classical reasoner and simplifier:
  1573   + functions for handling clasimpsets
  1574   + improvement of addss: now the simplifier is called _after_ the
  1575     safe steps.
  1576   + safe variant of addss called addSss: uses safe simplifications
  1577     _during_ the safe steps. It is more complete as it allows multiple
  1578     instantiations of unknowns (e.g. with slow_tac).
  1579 
  1580 *** Simplifier ***
  1581 
  1582 * added interface for simplification procedures (functions that
  1583 produce *proven* rewrite rules on the fly, depending on current
  1584 redex);
  1585 
  1586 * ordering on terms as parameter (used for ordered rewriting);
  1587 
  1588 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1589 
  1590 * the solver is now split into a safe and an unsafe part.
  1591 This should be invisible for the normal user, except that the
  1592 functions setsolver and addsolver have been renamed to setSolver and
  1593 addSolver; added safe_asm_full_simp_tac;
  1594 
  1595 
  1596 *** HOL ***
  1597 
  1598 * a generic induction tactic `induct_tac' which works for all datatypes and
  1599 also for type `nat';
  1600 
  1601 * a generic case distinction tactic `exhaust_tac' which works for all
  1602 datatypes and also for type `nat';
  1603 
  1604 * each datatype comes with a function `size';
  1605 
  1606 * patterns in case expressions allow tuple patterns as arguments to
  1607 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1608 
  1609 * primrec now also works with type nat;
  1610 
  1611 * recdef: a new declaration form, allows general recursive functions to be
  1612 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1613 
  1614 * the constant for negation has been renamed from "not" to "Not" to
  1615 harmonize with FOL, ZF, LK, etc.;
  1616 
  1617 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1618 infinite lists;
  1619 
  1620 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1621 
  1622 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1623 problems in commutative rings, using axiomatic type classes for + and *;
  1624 
  1625 * more examples in HOL/MiniML and HOL/Auth;
  1626 
  1627 * more default rewrite rules for quantifiers, union/intersection;
  1628 
  1629 * a new constant `arbitrary == @x.False';
  1630 
  1631 * HOLCF/IOA replaces old HOL/IOA;
  1632 
  1633 * HOLCF changes: derived all rules and arities
  1634   + axiomatic type classes instead of classes
  1635   + typedef instead of faking type definitions
  1636   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1637   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1638   + eliminated the types void, one, tr
  1639   + use unit lift and bool lift (with translations) instead of one and tr
  1640   + eliminated blift from Lift3.thy (use Def instead of blift)
  1641   all eliminated rules are derived as theorems --> no visible changes ;
  1642 
  1643 
  1644 *** ZF ***
  1645 
  1646 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1647 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1648 as ZF_cs addSIs [equalityI];
  1649 
  1650 
  1651 
  1652 New in Isabelle94-7 (November 96)
  1653 ---------------------------------
  1654 
  1655 * allowing negative levels (as offsets) in prlev and choplev;
  1656 
  1657 * super-linear speedup for large simplifications;
  1658 
  1659 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1660 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1661 FAIL); can suppress it using the command Delsimps (ex_simps @
  1662 all_simps); De Morgan laws are also now included, by default;
  1663 
  1664 * improved printing of ==>  :  ~:
  1665 
  1666 * new object-logic "Sequents" adds linear logic, while replacing LK
  1667 and Modal (thanks to Sara Kalvala);
  1668 
  1669 * HOL/Auth: correctness proofs for authentication protocols;
  1670 
  1671 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1672 examples on HOL/Auth);
  1673 
  1674 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1675 the rewriter and classical reasoner simultaneously;
  1676 
  1677 * function uresult no longer returns theorems in "standard" format;
  1678 regain previous version by: val uresult = standard o uresult;
  1679 
  1680 
  1681 
  1682 New in Isabelle94-6
  1683 -------------------
  1684 
  1685 * oracles -- these establish an interface between Isabelle and trusted
  1686 external reasoners, which may deliver results as theorems;
  1687 
  1688 * proof objects (in particular record all uses of oracles);
  1689 
  1690 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1691 
  1692 * "constdefs" section in theory files;
  1693 
  1694 * "primrec" section (HOL) no longer requires names;
  1695 
  1696 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1697 
  1698 
  1699 
  1700 New in Isabelle94-5
  1701 -------------------
  1702 
  1703 * reduced space requirements;
  1704 
  1705 * automatic HTML generation from theories;
  1706 
  1707 * theory files no longer require "..." (quotes) around most types;
  1708 
  1709 * new examples, including two proofs of the Church-Rosser theorem;
  1710 
  1711 * non-curried (1994) version of HOL is no longer distributed;
  1712 
  1713 
  1714 
  1715 New in Isabelle94-4
  1716 -------------------
  1717 
  1718 * greatly reduced space requirements;
  1719 
  1720 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1721 
  1722 * searchable theorem database (see the section "Retrieving theorems" on
  1723 page 8 of the Reference Manual);
  1724 
  1725 * new examples, including Grabczewski's monumental case study of the
  1726 Axiom of Choice;
  1727 
  1728 * The previous version of HOL renamed to Old_HOL;
  1729 
  1730 * The new version of HOL (previously called CHOL) uses a curried syntax
  1731 for functions.  Application looks like f a b instead of f(a,b);
  1732 
  1733 * Mutually recursive inductive definitions finally work in HOL;
  1734 
  1735 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1736 translates to the operator "split";
  1737 
  1738 
  1739 
  1740 New in Isabelle94-3
  1741 -------------------
  1742 
  1743 * new infix operator, addss, allowing the classical reasoner to
  1744 perform simplification at each step of its search.  Example:
  1745         fast_tac (cs addss ss)
  1746 
  1747 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1748 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1749 look like (a,b) instead of <a,b>;
  1750 
  1751 * PLEASE NOTE: CHOL will eventually replace HOL!
  1752 
  1753 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1754 It translates to the operator "split".  A new theory of integers is available;
  1755 
  1756 * In ZF, integer numerals now denote two's-complement binary integers.
  1757 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1758 
  1759 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1760 of the Axiom of Choice;
  1761 
  1762 
  1763 
  1764 New in Isabelle94-2
  1765 -------------------
  1766 
  1767 * Significantly faster resolution;
  1768 
  1769 * the different sections in a .thy file can now be mixed and repeated
  1770 freely;
  1771 
  1772 * Database of theorems for FOL, HOL and ZF.  New
  1773 commands including qed, qed_goal and bind_thm store theorems in the database.
  1774 
  1775 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1776 a given theory (thms_of), or find out what theory a theorem was proved in
  1777 (theory_of_thm);
  1778 
  1779 * Bugs fixed in the inductive definition and datatype packages;
  1780 
  1781 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1782 and HOL_dup_cs obsolete;
  1783 
  1784 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1785 have been removed;
  1786 
  1787 * Simpler definition of function space in ZF;
  1788 
  1789 * new results about cardinal and ordinal arithmetic in ZF;
  1790 
  1791 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1792 types;
  1793 
  1794 
  1795 $Id$