NEWS
author wenzelm
Sat Feb 03 15:20:55 2001 +0100 (2001-02-03)
changeset 11043 2e3bbac8763b
parent 11016 8f8ba41a5e7a
child 11050 ac5709ac50b9
permissions -rw-r--r--
HOL: inductive package no longer splits induction rule aggressively,
but only as far as specified by the introductions given; the old
format may recovered via ML function complete_split_rule or attribute
'split_rule (complete)';
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 *** Overview of INCOMPATIBILITIES ***
     6 
     7 * HOL: inductive package no longer splits induction rule aggressively,
     8 but only as far as specified by the introductions given; the old
     9 format may recovered via ML function complete_split_rule or attribute
    10 'split_rule (complete)';
    11 
    12 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
    13 gfp_Tarski to gfp_unfold;
    14 
    15 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
    16 
    17 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
    18 relation); infix "^^" has been renamed "``"; infix "``" has been
    19 renamed "`"; "univalent" has been renamed "single_valued";
    20 
    21 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
    22 operation;
    23 
    24 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
    25 
    26 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
    27 
    28 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
    29 consequence, it is no longer monotonic wrt. the local goal context
    30 (which is now passed through the inductive cases);
    31 
    32 * Document preparation: renamed standard symbols \<ll> to \<lless> and
    33 \<gg> to \<ggreater>;
    34 
    35 
    36 *** Document preparation ***
    37 
    38 * \isabellestyle{NAME} selects version of Isabelle output (currently
    39 available: are "it" for near math-mode best-style output, "sl" for
    40 slanted text style, and "tt" for plain type-writer; if no
    41 \isabellestyle command is given, output is according to slanted
    42 type-writer);
    43 
    44 * support sub/super scripts (for single symbols only), input syntax is
    45 like this: "A\<^sup>*" or "A\<^sup>\<star>";
    46 
    47 * some more standard symbols; see Appendix A of the system manual for
    48 the complete list;
    49 
    50 * improved isabelle style files; more abstract symbol implementation
    51 (should now use \isamath{...} and \isatext{...} in custom symbol
    52 definitions);
    53 
    54 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
    55 state; Note that presentation of goal states does not conform to
    56 actual human-readable proof documents.  Please do not include goal
    57 states into document output unless you really know what you are doing!
    58 
    59 * isatool unsymbolize tunes sources for plain ASCII communication;
    60 
    61 
    62 *** Isar ***
    63 
    64 * Pure: Isar now suffers initial goal statements to contain unbound
    65 schematic variables (this does not conform to actual readable proof
    66 documents, due to unpredictable outcome and non-compositional proof
    67 checking); users who know what they are doing may use schematic goals
    68 for Prolog-style synthesis of proven results;
    69 
    70 * Pure: assumption method (an implicit finishing) now handles actual
    71 rules as well;
    72 
    73 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
    74 initial goal, declare "that" only as Pure intro (only for single
    75 steps); the "that" rule assumption may now be involved in implicit
    76 finishing, thus ".." becomes a feasible for trivial obtains;
    77 
    78 * Pure: default proof step now includes 'intro_classes'; thus trivial
    79 instance proofs may be performed by "..";
    80 
    81 * Pure: ?thesis / ?this / "..." now work for pure meta-level
    82 statements as well;
    83 
    84 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
    85 rule (as well as the assumption rule);
    86 
    87 * Pure: 'thm_deps' command visualizes dependencies of theorems and
    88 lemmas, using the graph browser tool;
    89 
    90 * Pure: predict failure of "show" in interactive mode;
    91 
    92 * Pure: 'thms_containing' now takes actual terms as arguments;
    93 
    94 * HOL: improved method 'induct' --- now handles non-atomic goals
    95 (potential INCOMPATIBILITY); tuned error handling;
    96 
    97 * HOL: cases and induct rules now provide explicit hints about the
    98 number of facts to be consumed (0 for "type" and 1 for "set" rules);
    99 any remaining facts are inserted into the goal verbatim;
   100 
   101 * HOL: local contexts (aka cases) may now contain term bindings as
   102 well; the 'cases' and 'induct' methods new provide a ?case binding for
   103 the result to be shown in each case;
   104 
   105 * HOL: added 'recdef_tc' command;
   106 
   107 * isatool convert assists in eliminating legacy ML scripts;
   108 
   109 
   110 *** HOL ***
   111 
   112 * HOL/Library: a collection of generic theories to be used together
   113 with main HOL; the theory loader path already includes this directory
   114 by default; the following existing theories have been moved here:
   115 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   116 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   117 
   118 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   119 modelling and verification task performed in Isabelle/HOL +
   120 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   121 
   122 * HOL basics: added overloaded operations "inverse" and "divide"
   123 (infix "/"), syntax for generic "abs" operation, generic summation
   124 operator;
   125 
   126 * HOL/typedef: simplified package, provide more useful rules (see also
   127 HOL/subset.thy);
   128 
   129 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   130 now expressed as a proper nested rule (old-style tactic scripts may
   131 require atomize_strip_tac to cope with non-atomic premises);
   132 
   133 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   134 to "split_conv" (old name still available for compatibility);
   135 
   136 * HOL: improved concrete syntax for strings (e.g. allows translation
   137 rules with string literals);
   138 
   139 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   140 and Fleuriot's mechanization of analysis;
   141 
   142 * HOL-Real, HOL-Hyperreals: improved arithmetic simplification;
   143 
   144 
   145 *** CTT ***
   146 
   147 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   148 "lam" is displayed as TWO lambda-symbols
   149 
   150 * CTT: theory Main now available, containing everything (that is, Bool
   151 and Arith);
   152 
   153 
   154 *** General ***
   155 
   156 * print modes "brackets" and "no_brackets" control output of nested =>
   157 (types) and ==> (props); the default behaviour is "brackets";
   158 
   159 * system: support Poly/ML 4.0 (current beta versions);
   160 
   161 * Pure: the Simplifier has been implemented properly as a derived rule
   162 outside of the actual kernel (at last!); the overall performance
   163 penalty in practical applications is about 50%, while reliability of
   164 the Isabelle inference kernel has been greatly improved;
   165 
   166 * Provers: fast_tac (and friends) now handle actual object-logic rules
   167 as assumptions as well;
   168 
   169 
   170 
   171 New in Isabelle99-1 (October 2000)
   172 ----------------------------------
   173 
   174 *** Overview of INCOMPATIBILITIES ***
   175 
   176 * HOL: simplification of natural numbers is much changed; to partly
   177 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   178 issue the following ML commands:
   179 
   180   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   181   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   182 
   183 * HOL: simplification no longer dives into case-expressions; this is
   184 controlled by "t.weak_case_cong" for each datatype t;
   185 
   186 * HOL: nat_less_induct renamed to less_induct;
   187 
   188 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   189 fixsome to patch .thy and .ML sources automatically;
   190 
   191   select_equality  -> some_equality
   192   select_eq_Ex     -> some_eq_ex
   193   selectI2EX       -> someI2_ex
   194   selectI2         -> someI2
   195   selectI          -> someI
   196   select1_equality -> some1_equality
   197   Eps_sym_eq       -> some_sym_eq_trivial
   198   Eps_eq           -> some_eq_trivial
   199 
   200 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   201 
   202 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   203 instead);
   204 
   205 * HOL: the recursion equations generated by 'recdef' are now called
   206 f.simps instead of f.rules;
   207 
   208 * HOL: qed_spec_mp now also handles bounded ALL as well;
   209 
   210 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   211 sometimes be needed;
   212 
   213 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   214 
   215 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   216 
   217 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   218 product is now "<*>" instead of "Times"; the lexicographic product is
   219 now "<*lex*>" instead of "**";
   220 
   221 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   222 of main HOL, but was unused); better use HOL's datatype package;
   223 
   224 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   225 the old syntax may be recovered as follows:
   226 
   227   syntax (symbols)
   228     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   229       (infixl "\\<oplus>" 100)
   230 
   231 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   232 
   233 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   234 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   235 internally;
   236 
   237 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   238 changed from A/r to A//r;
   239 
   240 * ZF: new treatment of arithmetic (nat & int) may break some old
   241 proofs;
   242 
   243 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   244 rulify -> rule_format, elimify -> elim_format, ...);
   245 
   246 * Isar/Provers: intro/elim/dest attributes changed; renamed
   247 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   248 should have to change intro!! to intro? only); replaced "delrule" by
   249 "rule del";
   250 
   251 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   252 
   253 * Provers: strengthened force_tac by using new first_best_tac;
   254 
   255 * LaTeX document preparation: several changes of isabelle.sty (see
   256 lib/texinputs);
   257 
   258 
   259 *** Document preparation ***
   260 
   261 * formal comments (text blocks etc.) in new-style theories may now
   262 contain antiquotations of thm/prop/term/typ/text to be presented
   263 according to latex print mode; concrete syntax is like this:
   264 @{term[show_types] "f(x) = a + x"};
   265 
   266 * isatool mkdir provides easy setup of Isabelle session directories,
   267 including proper document sources;
   268 
   269 * generated LaTeX sources are now deleted after successful run
   270 (isatool document -c); may retain a copy somewhere else via -D option
   271 of isatool usedir;
   272 
   273 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   274 style files, achieving self-contained LaTeX sources and simplifying
   275 LaTeX debugging;
   276 
   277 * old-style theories now produce (crude) LaTeX output as well;
   278 
   279 * browser info session directories are now self-contained (may be put
   280 on WWW server seperately); improved graphs of nested sessions; removed
   281 graph for 'all sessions';
   282 
   283 * several improvements in isabelle style files; \isabellestyle{it}
   284 produces fake math mode output; \isamarkupheader is now \section by
   285 default; see lib/texinputs/isabelle.sty etc.;
   286 
   287 
   288 *** Isar ***
   289 
   290 * Isar/Pure: local results and corresponding term bindings are now
   291 subject to Hindley-Milner polymorphism (similar to ML); this
   292 accommodates incremental type-inference very nicely;
   293 
   294 * Isar/Pure: new derived language element 'obtain' supports
   295 generalized existence reasoning;
   296 
   297 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   298 support accumulation of results, without applying any rules yet;
   299 useful to collect intermediate results without explicit name
   300 references, and for use with transitivity rules with more than 2
   301 premises;
   302 
   303 * Isar/Pure: scalable support for case-analysis type proofs: new
   304 'case' language element refers to local contexts symbolically, as
   305 produced by certain proof methods; internally, case names are attached
   306 to theorems as "tags";
   307 
   308 * Isar/Pure: theory command 'hide' removes declarations from
   309 class/type/const name spaces;
   310 
   311 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   312 indicate potential overloading;
   313 
   314 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   315 
   316 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   317 "{a,b,c}" instead of {a,b,c};
   318 
   319 * Isar/Pure now provides its own version of intro/elim/dest
   320 attributes; useful for building new logics, but beware of confusion
   321 with the version in Provers/classical;
   322 
   323 * Isar/Pure: the local context of (non-atomic) goals is provided via
   324 case name 'antecedent';
   325 
   326 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   327 to the current context is now done automatically);
   328 
   329 * Isar/Pure: theory command 'method_setup' provides a simple interface
   330 for definining proof methods in ML;
   331 
   332 * Isar/Provers: intro/elim/dest attributes changed; renamed
   333 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   334 most cases, one should have to change intro!! to intro? only);
   335 replaced "delrule" by "rule del";
   336 
   337 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   338 'symmetric' attribute (the latter supercedes [RS sym]);
   339 
   340 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   341 method modifier); 'simp' method: 'only:' modifier removes loopers as
   342 well (including splits);
   343 
   344 * Isar/Provers: Simplifier and Classical methods now support all kind
   345 of modifiers used in the past, including 'cong', 'iff', etc.
   346 
   347 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   348 of Simplifier and Classical reasoner);
   349 
   350 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   351 now support named cases; major packages (inductive, datatype, primrec,
   352 recdef) support case names and properly name parameters;
   353 
   354 * Isar/HOL: new transitivity rules for substitution in inequalities --
   355 monotonicity conditions are extracted to be proven at end of
   356 calculations;
   357 
   358 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   359 method anyway;
   360 
   361 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   362 split_if split_if_asm; datatype package provides theorems foo.splits =
   363 foo.split foo.split_asm for each datatype;
   364 
   365 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   366 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   367 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   368 use "(cases (simplified))" method in proper proof texts);
   369 
   370 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   371 
   372 * Isar: names of theorems etc. may be natural numbers as well;
   373 
   374 * Isar: 'pr' command: optional arguments for goals_limit and
   375 ProofContext.prems_limit; no longer prints theory contexts, but only
   376 proof states;
   377 
   378 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   379 additional print modes to be specified; e.g. "pr(latex)" will print
   380 proof state according to the Isabelle LaTeX style;
   381 
   382 * Isar: improved support for emulating tactic scripts, including proof
   383 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   384 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   385 (for HOL datatypes);
   386 
   387 * Isar: simplified (more robust) goal selection of proof methods: 1st
   388 goal, all goals, or explicit goal specifier (tactic emulation); thus
   389 'proof method scripts' have to be in depth-first order;
   390 
   391 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   392 
   393 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   394 should instead use individual commands for printing items
   395 (print_commands, print_methods etc.);
   396 
   397 * Isar: added 'nothing' --- the empty list of theorems;
   398 
   399 
   400 *** HOL ***
   401 
   402 * HOL/MicroJava: formalization of a fragment of Java, together with a
   403 corresponding virtual machine and a specification of its bytecode
   404 verifier and a lightweight bytecode verifier, including proofs of
   405 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   406 Cornelia Pusch (see also the homepage of project Bali at
   407 http://isabelle.in.tum.de/Bali/);
   408 
   409 * HOL/Algebra: new theory of rings and univariate polynomials, by
   410 Clemens Ballarin;
   411 
   412 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   413 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   414 Rasmussen;
   415 
   416 * HOL/Lattice: fundamental concepts of lattice theory and order
   417 structures, including duals, properties of bounds versus algebraic
   418 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   419 Theorem for complete lattices etc.; may also serve as a demonstration
   420 for abstract algebraic reasoning using axiomatic type classes, and
   421 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   422 
   423 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   424 von Oheimb;
   425 
   426 * HOL/IMPP: extension of IMP with local variables and mutually
   427 recursive procedures, by David von Oheimb;
   428 
   429 * HOL/Lambda: converted into new-style theory and document;
   430 
   431 * HOL/ex/Multiquote: example of multiple nested quotations and
   432 anti-quotations -- basically a generalized version of de-Bruijn
   433 representation; very useful in avoiding lifting of operations;
   434 
   435 * HOL/record: added general record equality rule to simpset; fixed
   436 select-update simplification procedure to handle extended records as
   437 well; admit "r" as field name;
   438 
   439 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   440 other numeric types and also as the identity of groups, rings, etc.;
   441 
   442 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   443 Types nat and int belong to this axclass;
   444 
   445 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   446    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   447    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   448   two terms #m*u and #n*u are replaced by #(m+n)*u
   449     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   450   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   451     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   452 
   453 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   454 powerful prover for predicate logic but knows nothing of clasets; see
   455 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   456 
   457 * HOL: new version of "case_tac" subsumes both boolean case split and
   458 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   459 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   460 
   461 * HOL: simplification no longer dives into case-expressions: only the
   462 selector expression is simplified, but not the remaining arms; to
   463 enable full simplification of case-expressions for datatype t, you may
   464 remove t.weak_case_cong from the simpset, either globally (Delcongs
   465 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   466 
   467 * HOL/recdef: the recursion equations generated by 'recdef' for
   468 function 'f' are now called f.simps instead of f.rules; if all
   469 termination conditions are proved automatically, these simplification
   470 rules are added to the simpset, as in primrec; rules may be named
   471 individually as well, resulting in a separate list of theorems for
   472 each equation;
   473 
   474 * HOL/While is a new theory that provides a while-combinator. It
   475 permits the definition of tail-recursive functions without the
   476 provision of a termination measure. The latter is necessary once the
   477 invariant proof rule for while is applied.
   478 
   479 * HOL: new (overloaded) notation for the set of elements below/above
   480 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   481 
   482 * HOL: theorems impI, allI, ballI bound as "strip";
   483 
   484 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   485 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   486 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   487 
   488 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   489 
   490 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   491 main HOL, but was unused);
   492 
   493 * HOL: fewer consts declared as global (e.g. have to refer to
   494 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   495 
   496 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   497 in case of overlap with user translations (e.g. judgements over
   498 tuples); (note that the underlying logical represenation is still
   499 bogus);
   500 
   501 
   502 *** ZF ***
   503 
   504 * ZF: simplification automatically cancels common terms in arithmetic
   505 expressions over nat and int;
   506 
   507 * ZF: new treatment of nat to minimize type-checking: all operators
   508 coerce their operands to a natural number using the function natify,
   509 making the algebraic laws unconditional;
   510 
   511 * ZF: as above, for int: operators coerce their operands to an integer
   512 using the function intify;
   513 
   514 * ZF: the integer library now contains many of the usual laws for the
   515 orderings, including $<=, and monotonicity laws for $+ and $*;
   516 
   517 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   518 simplification;
   519 
   520 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   521 to the simplifier and classical reasoner simultaneously;
   522 
   523 
   524 *** General ***
   525 
   526 * Provers: blast_tac now handles actual object-logic rules as
   527 assumptions; note that auto_tac uses blast_tac internally as well;
   528 
   529 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   530 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   531 
   532 * Provers: delrules now handles destruct rules as well (no longer need
   533 explicit make_elim);
   534 
   535 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   536   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   537 use instead the strong form,
   538   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   539 in HOL, FOL and ZF the function cla_make_elim will create such rules
   540 from destruct-rules;
   541 
   542 * Provers: Simplifier.easy_setup provides a fast path to basic
   543 Simplifier setup for new object-logics;
   544 
   545 * Pure: AST translation rules no longer require constant head on LHS;
   546 
   547 * Pure: improved name spaces: ambiguous output is qualified; support
   548 for hiding of names;
   549 
   550 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   551 XSYMBOL_HOME; no longer need to do manual configuration in most
   552 situations;
   553 
   554 * system: compression of ML heaps images may now be controlled via -c
   555 option of isabelle and isatool usedir (currently only observed by
   556 Poly/ML);
   557 
   558 * system: isatool installfonts may handle X-Symbol fonts as well (very
   559 useful for remote X11);
   560 
   561 * system: provide TAGS file for Isabelle sources;
   562 
   563 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   564 order;
   565 
   566 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   567 timing flag supersedes proof_timing and Toplevel.trace;
   568 
   569 * ML: new combinators |>> and |>>> for incremental transformations
   570 with secondary results (e.g. certain theory extensions):
   571 
   572 * ML: PureThy.add_defs gets additional argument to indicate potential
   573 overloading (usually false);
   574 
   575 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   576 results;
   577 
   578 
   579 
   580 New in Isabelle99 (October 1999)
   581 --------------------------------
   582 
   583 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   584 
   585 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   586 are no longer simplified.  (This allows the simplifier to unfold recursive
   587 functional programs.)  To restore the old behaviour, declare
   588 
   589     Delcongs [if_weak_cong];
   590 
   591 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   592 complement;
   593 
   594 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   595 
   596 * HOL/datatype: mutual_induct_tac no longer exists --
   597   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   598 
   599 * HOL/typedef: fixed type inference for representing set; type
   600 arguments now have to occur explicitly on the rhs as type constraints;
   601 
   602 * ZF: The con_defs part of an inductive definition may no longer refer
   603 to constants declared in the same theory;
   604 
   605 * HOL, ZF: the function mk_cases, generated by the inductive
   606 definition package, has lost an argument.  To simplify its result, it
   607 uses the default simpset instead of a supplied list of theorems.
   608 
   609 * HOL/List: the constructors of type list are now Nil and Cons;
   610 
   611 * Simplifier: the type of the infix ML functions
   612         setSSolver addSSolver setSolver addSolver
   613 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   614 for packaging solvers. A solver is created via
   615         mk_solver: string -> (thm list -> int -> tactic) -> solver
   616 where the string argument is only a comment.
   617 
   618 
   619 *** Proof tools ***
   620 
   621 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   622 decision procedure for linear arithmetic. Currently it is used for
   623 types `nat', `int', and `real' in HOL (see below); it can, should and
   624 will be instantiated for other types and logics as well.
   625 
   626 * The simplifier now accepts rewrite rules with flexible heads, eg
   627      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   628   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   629   matching.
   630 
   631 
   632 *** General ***
   633 
   634 * New Isabelle/Isar subsystem provides an alternative to traditional
   635 tactical theorem proving; together with the ProofGeneral/isar user
   636 interface it offers an interactive environment for developing human
   637 readable proof documents (Isar == Intelligible semi-automated
   638 reasoning); for further information see isatool doc isar-ref,
   639 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   640 
   641 * improved and simplified presentation of theories: better HTML markup
   642 (including colors), graph views in several sizes; isatool usedir now
   643 provides a proper interface for user theories (via -P option); actual
   644 document preparation based on (PDF)LaTeX is available as well (for
   645 new-style theories only); see isatool doc system for more information;
   646 
   647 * native support for Proof General, both for classic Isabelle and
   648 Isabelle/Isar;
   649 
   650 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   651 using the graph browser tool;
   652 
   653 * Isabelle manuals now also available as PDF;
   654 
   655 * theory loader rewritten from scratch (may not be fully
   656 bug-compatible); old loadpath variable has been replaced by show_path,
   657 add_path, del_path, reset_path functions; new operations such as
   658 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   659 isatool doc ref);
   660 
   661 * improved isatool install: option -k creates KDE application icon,
   662 option -p DIR installs standalone binaries;
   663 
   664 * added ML_PLATFORM setting (useful for cross-platform installations);
   665 more robust handling of platform specific ML images for SML/NJ;
   666 
   667 * the settings environment is now statically scoped, i.e. it is never
   668 created again in sub-processes invoked from isabelle, isatool, or
   669 Isabelle;
   670 
   671 * path element specification '~~' refers to '$ISABELLE_HOME';
   672 
   673 * in locales, the "assumes" and "defines" parts may be omitted if
   674 empty;
   675 
   676 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   677 long arrows);
   678 
   679 * new print_mode "HTML";
   680 
   681 * new flag show_tags controls display of tags of theorems (which are
   682 basically just comments that may be attached by some tools);
   683 
   684 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   685 mode and goal output format:
   686 
   687 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   688 244c244
   689 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   690 ---
   691 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   692 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   693 181c181
   694 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   695 ---
   696 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   697 
   698 * function bind_thms stores lists of theorems (cf. bind_thm);
   699 
   700 * new shorthand tactics ftac, eatac, datac, fatac;
   701 
   702 * qed (and friends) now accept "" as result name; in that case the
   703 theorem is not stored, but proper checks and presentation of the
   704 result still apply;
   705 
   706 * theorem database now also indexes constants "Trueprop", "all",
   707 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   708 
   709 
   710 *** HOL ***
   711 
   712 ** HOL arithmetic **
   713 
   714 * There are now decision procedures for linear arithmetic over nat and
   715 int:
   716 
   717 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   718 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   719 are treated as atomic; subformulae not involving type `nat' or `int'
   720 are ignored; quantified subformulae are ignored unless they are
   721 positive universal or negative existential. The tactic has to be
   722 invoked by hand and can be a little bit slow. In particular, the
   723 running time is exponential in the number of occurrences of `min' and
   724 `max', and `-' on `nat'.
   725 
   726 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   727 (negated) (in)equalities among the premises and the conclusion into
   728 account (i.e. no compound formulae) and does not know about `min' and
   729 `max', and `-' on `nat'. It is fast and is used automatically by the
   730 simplifier.
   731 
   732 NB: At the moment, these decision procedures do not cope with mixed
   733 nat/int formulae where the two parts interact, such as `m < n ==>
   734 int(m) < int(n)'.
   735 
   736 * HOL/Numeral provides a generic theory of numerals (encoded
   737 efficiently as bit strings); setup for types nat/int/real is in place;
   738 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   739 int, existing theories and proof scripts may require a few additional
   740 type constraints;
   741 
   742 * integer division and remainder can now be performed on constant
   743 arguments;
   744 
   745 * many properties of integer multiplication, division and remainder
   746 are now available;
   747 
   748 * An interface to the Stanford Validity Checker (SVC) is available through the
   749 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   750 are proved automatically.  SVC must be installed separately, and its results
   751 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   752 invocation of the underlying oracle).  For SVC see
   753   http://verify.stanford.edu/SVC
   754 
   755 * IsaMakefile: the HOL-Real target now builds an actual image;
   756 
   757 
   758 ** HOL misc **
   759 
   760 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   761 (in Isabelle/Isar) -- by Gertrud Bauer;
   762 
   763 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   764 analysis for assembly languages with subtypes;
   765 
   766 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   767 -- avoids syntactic ambiguities and treats state, transition, and
   768 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   769 changed syntax and (many) tactics;
   770 
   771 * HOL/inductive: Now also handles more general introduction rules such
   772   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   773   theorems are now maintained within the theory (maintained via the
   774   "mono" attribute);
   775 
   776 * HOL/datatype: Now also handles arbitrarily branching datatypes
   777   (using function types) such as
   778 
   779   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   780 
   781 * HOL/record: record_simproc (part of the default simpset) takes care
   782 of selectors applied to updated records; record_split_tac is no longer
   783 part of the default claset; update_defs may now be removed from the
   784 simpset in many cases; COMPATIBILITY: old behavior achieved by
   785 
   786   claset_ref () := claset() addSWrapper record_split_wrapper;
   787   Delsimprocs [record_simproc]
   788 
   789 * HOL/typedef: fixed type inference for representing set; type
   790 arguments now have to occur explicitly on the rhs as type constraints;
   791 
   792 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   793 names rather than an ML expression;
   794 
   795 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   796 supplied later.  Program schemes can be defined, such as
   797     "While B C s = (if B s then While B C (C s) else s)"
   798 where the well-founded relation can be chosen after B and C have been given.
   799 
   800 * HOL/List: the constructors of type list are now Nil and Cons;
   801 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   802 course, ML tools referring to List.list.op # etc. have to be adapted;
   803 
   804 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   805 disabled by default; run isabelle with option -m HOL to get back to
   806 the original Gordon/HOL-style output;
   807 
   808 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   809 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   810 
   811 * HOL basic syntax simplified (more orthogonal): all variants of
   812 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   813 Eps operator is provided as well: "SOME x. P[x]";
   814 
   815 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   816 
   817 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   818 thus available for user theories;
   819 
   820 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   821 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   822 time;
   823 
   824 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   825 several times and then mp;
   826 
   827 
   828 *** LK ***
   829 
   830 * the notation <<...>> is now available as a notation for sequences of
   831 formulas;
   832 
   833 * the simplifier is now installed
   834 
   835 * the axiom system has been generalized (thanks to Soren Heilmann)
   836 
   837 * the classical reasoner now has a default rule database
   838 
   839 
   840 *** ZF ***
   841 
   842 * new primrec section allows primitive recursive functions to be given
   843 directly (as in HOL) over datatypes and the natural numbers;
   844 
   845 * new tactics induct_tac and exhaust_tac for induction (or case
   846 analysis) over datatypes and the natural numbers;
   847 
   848 * the datatype declaration of type T now defines the recursor T_rec;
   849 
   850 * simplification automatically does freeness reasoning for datatype
   851 constructors;
   852 
   853 * automatic type-inference, with AddTCs command to insert new
   854 type-checking rules;
   855 
   856 * datatype introduction rules are now added as Safe Introduction rules
   857 to the claset;
   858 
   859 * the syntax "if P then x else y" is now available in addition to
   860 if(P,x,y);
   861 
   862 
   863 *** Internal programming interfaces ***
   864 
   865 * tuned simplifier trace output; new flag debug_simp;
   866 
   867 * structures Vartab / Termtab (instances of TableFun) offer efficient
   868 tables indexed by indexname_ord / term_ord (compatible with aconv);
   869 
   870 * AxClass.axclass_tac lost the theory argument;
   871 
   872 * tuned current_goals_markers semantics: begin / end goal avoids
   873 printing empty lines;
   874 
   875 * removed prs and prs_fn hook, which was broken because it did not
   876 include \n in its semantics, forcing writeln to add one
   877 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   878 string -> unit if you really want to output text without newline;
   879 
   880 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   881 plain output, interface builders may have to enable 'isabelle_font'
   882 mode to get Isabelle font glyphs as before;
   883 
   884 * refined token_translation interface; INCOMPATIBILITY: output length
   885 now of type real instead of int;
   886 
   887 * theory loader actions may be traced via new ThyInfo.add_hook
   888 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   889 your own database of information attached to *whole* theories -- as
   890 opposed to intra-theory data slots offered via TheoryDataFun;
   891 
   892 * proper handling of dangling sort hypotheses (at last!);
   893 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   894 extra sort hypotheses that can be witnessed from the type signature;
   895 the force_strip_shyps flag is gone, any remaining shyps are simply
   896 left in the theorem (with a warning issued by strip_shyps_warning);
   897 
   898 
   899 
   900 New in Isabelle98-1 (October 1998)
   901 ----------------------------------
   902 
   903 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   904 
   905 * several changes of automated proof tools;
   906 
   907 * HOL: major changes to the inductive and datatype packages, including
   908 some minor incompatibilities of theory syntax;
   909 
   910 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   911 called `inj_on';
   912 
   913 * HOL: removed duplicate thms in Arith:
   914   less_imp_add_less  should be replaced by  trans_less_add1
   915   le_imp_add_le      should be replaced by  trans_le_add1
   916 
   917 * HOL: unary minus is now overloaded (new type constraints may be
   918 required);
   919 
   920 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   921 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   922 now taken as an integer constant.
   923 
   924 * Pure: ML function 'theory_of' renamed to 'theory';
   925 
   926 
   927 *** Proof tools ***
   928 
   929 * Simplifier:
   930   1. Asm_full_simp_tac is now more aggressive.
   931      1. It will sometimes reorient premises if that increases their power to
   932         simplify.
   933      2. It does no longer proceed strictly from left to right but may also
   934         rotate premises to achieve further simplification.
   935      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   936      old Asm_full_simp_tac in that it does not rotate premises.
   937   2. The simplifier now knows a little bit about nat-arithmetic.
   938 
   939 * Classical reasoner: wrapper mechanism for the classical reasoner now
   940 allows for selected deletion of wrappers, by introduction of names for
   941 wrapper functionals.  This implies that addbefore, addSbefore,
   942 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   943 and that adding two tactics with the same name overwrites the first
   944 one (emitting a warning).
   945   type wrapper = (int -> tactic) -> (int -> tactic)
   946   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   947   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   948   delWrapper, delSWrapper: claset *  string            -> claset
   949   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   950 
   951 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   952 semantics; addbefore now affects only the unsafe part of step_tac
   953 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   954 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   955 by Force_tac;
   956 
   957 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   958 compWrapper; added safe wrapper (and access functions for it);
   959 
   960 * HOL/split_all_tac is now much faster and fails if there is nothing
   961 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   962 and the names of the automatically generated variables have changed.
   963 split_all_tac has moved within claset() from unsafe wrappers to safe
   964 wrappers, which means that !!-bound variables are split much more
   965 aggressively, and safe_tac and clarify_tac now split such variables.
   966 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   967 Note: the same holds for record_split_tac, which does the job of
   968 split_all_tac for record fields.
   969 
   970 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   971 permanently to the default simpset using Addsplits just like
   972 Addsimps. They can be removed via Delsplits just like
   973 Delsimps. Lower-case versions are also available.
   974 
   975 * HOL/Simplifier: The rule split_if is now part of the default
   976 simpset. This means that the simplifier will eliminate all occurrences
   977 of if-then-else in the conclusion of a goal. To prevent this, you can
   978 either remove split_if completely from the default simpset by
   979 `Delsplits [split_if]' or remove it in a specific call of the
   980 simplifier using `... delsplits [split_if]'.  You can also add/delete
   981 other case splitting rules to/from the default simpset: every datatype
   982 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   983 t is the name of the datatype).
   984 
   985 * Classical reasoner / Simplifier combination: new force_tac (and
   986 derivatives Force_tac, force) combines rewriting and classical
   987 reasoning (and whatever other tools) similarly to auto_tac, but is
   988 aimed to solve the given subgoal completely.
   989 
   990 
   991 *** General ***
   992 
   993 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   994 and `goalw': the theory is no longer needed as an explicit argument -
   995 the current theory context is used; assumptions are no longer returned
   996 at the ML-level unless one of them starts with ==> or !!; it is
   997 recommended to convert to these new commands using isatool fixgoal
   998 (backup your sources first!);
   999 
  1000 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1001 the current theory context, and 'theory' to lookup stored theories;
  1002 
  1003 * new theory section 'locale' for declaring constants, assumptions and
  1004 definitions that have local scope;
  1005 
  1006 * new theory section 'nonterminals' for purely syntactic types;
  1007 
  1008 * new theory section 'setup' for generic ML setup functions
  1009 (e.g. package initialization);
  1010 
  1011 * the distribution now includes Isabelle icons: see
  1012 lib/logo/isabelle-{small,tiny}.xpm;
  1013 
  1014 * isatool install - install binaries with absolute references to
  1015 ISABELLE_HOME/bin;
  1016 
  1017 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1018 
  1019 * print mode 'emacs' reserved for Isamode;
  1020 
  1021 * support multiple print (ast) translations per constant name;
  1022 
  1023 * theorems involving oracles are now printed with a suffixed [!];
  1024 
  1025 
  1026 *** HOL ***
  1027 
  1028 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1029 
  1030 * HOL/inductive package reorganized and improved: now supports mutual
  1031 definitions such as
  1032 
  1033   inductive EVEN ODD
  1034     intrs
  1035       null "0 : EVEN"
  1036       oddI "n : EVEN ==> Suc n : ODD"
  1037       evenI "n : ODD ==> Suc n : EVEN"
  1038 
  1039 new theorem list "elims" contains an elimination rule for each of the
  1040 recursive sets; inductive definitions now handle disjunctive premises
  1041 correctly (also ZF);
  1042 
  1043 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1044 "mutual_induct" no longer exists - the induction rule is always
  1045 contained in "induct";
  1046 
  1047 
  1048 * HOL/datatype package re-implemented and greatly improved: now
  1049 supports mutually recursive datatypes such as
  1050 
  1051   datatype
  1052     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1053             | SUM ('a aexp) ('a aexp)
  1054             | DIFF ('a aexp) ('a aexp)
  1055             | NUM 'a
  1056   and
  1057     'a bexp = LESS ('a aexp) ('a aexp)
  1058             | AND ('a bexp) ('a bexp)
  1059             | OR ('a bexp) ('a bexp)
  1060 
  1061 as well as indirectly recursive datatypes such as
  1062 
  1063   datatype
  1064     ('a, 'b) term = Var 'a
  1065                   | App 'b ((('a, 'b) term) list)
  1066 
  1067 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1068 induction on mutually / indirectly recursive datatypes.
  1069 
  1070 Primrec equations are now stored in theory and can be accessed via
  1071 <function_name>.simps.
  1072 
  1073 INCOMPATIBILITIES:
  1074 
  1075   - Theories using datatypes must now have theory Datatype as an
  1076     ancestor.
  1077   - The specific <typename>.induct_tac no longer exists - use the
  1078     generic induct_tac instead.
  1079   - natE has been renamed to nat.exhaust - use exhaust_tac
  1080     instead of res_inst_tac ... natE. Note that the variable
  1081     names in nat.exhaust differ from the names in natE, this
  1082     may cause some "fragile" proofs to fail.
  1083   - The theorems split_<typename>_case and split_<typename>_case_asm
  1084     have been renamed to <typename>.split and <typename>.split_asm.
  1085   - Since default sorts of type variables are now handled correctly,
  1086     some datatype definitions may have to be annotated with explicit
  1087     sort constraints.
  1088   - Primrec definitions no longer require function name and type
  1089     of recursive argument.
  1090 
  1091 Consider using isatool fixdatatype to adapt your theories and proof
  1092 scripts to the new package (backup your sources first!).
  1093 
  1094 
  1095 * HOL/record package: considerably improved implementation; now
  1096 includes concrete syntax for record types, terms, updates; theorems
  1097 for surjective pairing and splitting !!-bound record variables; proof
  1098 support is as follows:
  1099 
  1100   1) standard conversions (selectors or updates applied to record
  1101 constructor terms) are part of the standard simpset;
  1102 
  1103   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1104 made part of standard simpset and claset via addIffs;
  1105 
  1106   3) a tactic for record field splitting (record_split_tac) is part of
  1107 the standard claset (addSWrapper);
  1108 
  1109 To get a better idea about these rules you may retrieve them via
  1110 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1111 the name of your record type.
  1112 
  1113 The split tactic 3) conceptually simplifies by the following rule:
  1114 
  1115   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1116 
  1117 Thus any record variable that is bound by meta-all will automatically
  1118 blow up into some record constructor term, consequently the
  1119 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1120 solve record problems automatically.
  1121 
  1122 
  1123 * reorganized the main HOL image: HOL/Integ and String loaded by
  1124 default; theory Main includes everything;
  1125 
  1126 * automatic simplification of integer sums and comparisons, using cancellation;
  1127 
  1128 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1129 
  1130 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1131 
  1132 * many new identities for unions, intersections, set difference, etc.;
  1133 
  1134 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1135 called split_if, split_split, split_sum_case and split_nat_case (to go
  1136 with add/delsplits);
  1137 
  1138 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1139 (?x::unit) = (); this is made part of the default simpset, which COULD
  1140 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1141 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1142 unit_abs_eta_conv is added in order to counter the effect of
  1143 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1144 %u.f();
  1145 
  1146 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1147 makes more sense);
  1148 
  1149 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1150   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1151   disjointness reasoning but breaking a few old proofs.
  1152 
  1153 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1154 to 'converse' from 'inverse' (for compatibility with ZF and some
  1155 literature);
  1156 
  1157 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1158 the well-founded relation;
  1159 
  1160 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1161     Compl A.  The "Compl" syntax remains available as input syntax for this
  1162     release ONLY.
  1163 
  1164 * HOL/Update: new theory of function updates:
  1165     f(a:=b) == %x. if x=a then b else f x
  1166 may also be iterated as in f(a:=b,c:=d,...);
  1167 
  1168 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1169 
  1170 * HOL/List:
  1171   - new function list_update written xs[i:=v] that updates the i-th
  1172     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1173   - new function `upt' written [i..j(] which generates the list
  1174     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1175     bound write [i..j], which is a shorthand for [i..j+1(].
  1176   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1177 
  1178 * HOL/Arith:
  1179   - removed 'pred' (predecessor) function;
  1180   - generalized some theorems about n-1;
  1181   - many new laws about "div" and "mod";
  1182   - new laws about greatest common divisors (see theory ex/Primes);
  1183 
  1184 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1185 instead of "inverse";
  1186 
  1187 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1188   of the multiset ordering;
  1189 
  1190 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1191   (not included by default);
  1192 
  1193 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1194 
  1195 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1196   programs, i.e. different program variables may have different types.
  1197 
  1198 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1199   [previously, this check worked only if the rewrite rule was unconditional]
  1200   Now rew can involve either definitions or equalities (either == or =).
  1201 
  1202 
  1203 *** ZF ***
  1204 
  1205 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1206   only the theorems proved on ZF.ML;
  1207 
  1208 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1209   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1210   disjointness reasoning but breaking a few old proofs.
  1211 
  1212 * ZF/Update: new theory of function updates
  1213     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1214   may also be iterated as in f(a:=b,c:=d,...);
  1215 
  1216 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1217 
  1218 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1219   [previously, this check worked only if the rewrite rule was unconditional]
  1220   Now rew can involve either definitions or equalities (either == or =).
  1221 
  1222 * case_tac provided for compatibility with HOL
  1223     (like the old excluded_middle_tac, but with subgoals swapped)
  1224 
  1225 
  1226 *** Internal programming interfaces ***
  1227 
  1228 * Pure: several new basic modules made available for general use, see
  1229 also src/Pure/README;
  1230 
  1231 * improved the theory data mechanism to support encapsulation (data
  1232 kind name replaced by private Object.kind, acting as authorization
  1233 key); new type-safe user interface via functor TheoryDataFun; generic
  1234 print_data function becomes basically useless;
  1235 
  1236 * removed global_names compatibility flag -- all theory declarations
  1237 are qualified by default;
  1238 
  1239 * module Pure/Syntax now offers quote / antiquote translation
  1240 functions (useful for Hoare logic etc. with implicit dependencies);
  1241 see HOL/ex/Antiquote for an example use;
  1242 
  1243 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1244 cterm -> thm;
  1245 
  1246 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1247 subgoal;
  1248 
  1249 * Display.print_goals function moved to Locale.print_goals;
  1250 
  1251 * standard print function for goals supports current_goals_markers
  1252 variable for marking begin of proof, end of proof, start of goal; the
  1253 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1254 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1255 for example;
  1256 
  1257 
  1258 
  1259 New in Isabelle98 (January 1998)
  1260 --------------------------------
  1261 
  1262 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1263 
  1264 * changed lexical syntax of terms / types: dots made part of long
  1265 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1266 
  1267 * simpset (and claset) reference variable replaced by functions
  1268 simpset / simpset_ref;
  1269 
  1270 * no longer supports theory aliases (via merge) and non-trivial
  1271 implicit merge of thms' signatures;
  1272 
  1273 * most internal names of constants changed due to qualified names;
  1274 
  1275 * changed Pure/Sequence interface (see Pure/seq.ML);
  1276 
  1277 
  1278 *** General Changes ***
  1279 
  1280 * hierachically structured name spaces (for consts, types, axms, thms
  1281 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1282 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1283 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1284 long_names for fully qualified output names; NOTE: ML programs
  1285 (special tactics, packages etc.) referring to internal names may have
  1286 to be adapted to cope with fully qualified names; in case of severe
  1287 backward campatibility problems try setting 'global_names' at compile
  1288 time to have enrything declared within a flat name space; one may also
  1289 fine tune name declarations in theories via the 'global' and 'local'
  1290 section;
  1291 
  1292 * reimplemented the implicit simpset and claset using the new anytype
  1293 data filed in signatures; references simpset:simpset ref etc. are
  1294 replaced by functions simpset:unit->simpset and
  1295 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1296 to patch your ML files accordingly;
  1297 
  1298 * HTML output now includes theory graph data for display with Java
  1299 applet or isatool browser; data generated automatically via isatool
  1300 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1301 
  1302 * defs may now be conditional; improved rewrite_goals_tac to handle
  1303 conditional equations;
  1304 
  1305 * defs now admits additional type arguments, using TYPE('a) syntax;
  1306 
  1307 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1308 creates a new theory node; implicit merge of thms' signatures is
  1309 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1310 transfer:theory->thm->thm in (rare) cases;
  1311 
  1312 * improved handling of draft signatures / theories; draft thms (and
  1313 ctyps, cterms) are automatically promoted to real ones;
  1314 
  1315 * slightly changed interfaces for oracles: admit many per theory, named
  1316 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1317 
  1318 * print_goals: optional output of const types (set show_consts and
  1319 show_types);
  1320 
  1321 * improved output of warnings (###) and errors (***);
  1322 
  1323 * subgoal_tac displays a warning if the new subgoal has type variables;
  1324 
  1325 * removed old README and Makefiles;
  1326 
  1327 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1328 
  1329 * removed obsolete init_pps and init_database;
  1330 
  1331 * deleted the obsolete tactical STATE, which was declared by
  1332     fun STATE tacfun st = tacfun st st;
  1333 
  1334 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1335 (which abbreviates $HOME);
  1336 
  1337 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1338 use isatool fixseq to adapt your ML programs (this works for fully
  1339 qualified references to the Sequence structure only!);
  1340 
  1341 * use_thy no longer requires writable current directory; it always
  1342 reloads .ML *and* .thy file, if either one is out of date;
  1343 
  1344 
  1345 *** Classical Reasoner ***
  1346 
  1347 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1348 tactics that use classical reasoning to simplify a subgoal without
  1349 splitting it into several subgoals;
  1350 
  1351 * Safe_tac: like safe_tac but uses the default claset;
  1352 
  1353 
  1354 *** Simplifier ***
  1355 
  1356 * added simplification meta rules:
  1357     (asm_)(full_)simplify: simpset -> thm -> thm;
  1358 
  1359 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1360 logics (again);
  1361 
  1362 * added prems argument to simplification procedures;
  1363 
  1364 * HOL, FOL, ZF: added infix function `addsplits':
  1365   instead of `<simpset> setloop (split_tac <thms>)'
  1366   you can simply write `<simpset> addsplits <thms>'
  1367 
  1368 
  1369 *** Syntax ***
  1370 
  1371 * TYPE('a) syntax for type reflection terms;
  1372 
  1373 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1374 
  1375 * pretty printer: changed order of mixfix annotation preference (again!);
  1376 
  1377 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1378 
  1379 
  1380 *** HOL ***
  1381 
  1382 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1383   with `addloop' of the simplifier to faciliate case splitting in premises.
  1384 
  1385 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1386 
  1387 * HOL/Auth: new protocol proofs including some for the Internet
  1388   protocol TLS;
  1389 
  1390 * HOL/Map: new theory of `maps' a la VDM;
  1391 
  1392 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1393 cancelling out common nat summands from =, <, <= (in)equalities, or
  1394 differences; simplification procedures nat_cancel_factor for
  1395 cancelling common factor from =, <, <= (in)equalities over natural
  1396 sums; nat_cancel contains both kinds of procedures, it is installed by
  1397 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1398 
  1399 * HOL/simplifier: terms of the form
  1400   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1401   are rewritten to
  1402   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1403   and those of the form
  1404   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1405   are rewritten to
  1406   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1407 
  1408 * HOL/datatype
  1409   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1410 
  1411   P(t_case f1 ... fn x) =
  1412      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1413         ...
  1414        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1415      )
  1416 
  1417   and a theorem `split_t_case_asm' of the form
  1418 
  1419   P(t_case f1 ... fn x) =
  1420     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1421         ...
  1422        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1423      )
  1424   which can be added to a simpset via `addsplits'. The existing theorems
  1425   expand_list_case and expand_option_case have been renamed to
  1426   split_list_case and split_option_case.
  1427 
  1428 * HOL/Arithmetic:
  1429   - `pred n' is automatically converted to `n-1'.
  1430     Users are strongly encouraged not to use `pred' any longer,
  1431     because it will disappear altogether at some point.
  1432   - Users are strongly encouraged to write "0 < n" rather than
  1433     "n ~= 0". Theorems and proof tools have been modified towards this
  1434     `standard'.
  1435 
  1436 * HOL/Lists:
  1437   the function "set_of_list" has been renamed "set" (and its theorems too);
  1438   the function "nth" now takes its arguments in the reverse order and
  1439   has acquired the infix notation "!" as in "xs!n".
  1440 
  1441 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1442 
  1443 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1444   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1445 
  1446 * HOL/record: extensible records with schematic structural subtyping
  1447 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1448 still lacks various theorems and concrete record syntax;
  1449 
  1450 
  1451 *** HOLCF ***
  1452 
  1453 * removed "axioms" and "generated by" sections;
  1454 
  1455 * replaced "ops" section by extended "consts" section, which is capable of
  1456   handling the continuous function space "->" directly;
  1457 
  1458 * domain package:
  1459   . proves theorems immediately and stores them in the theory,
  1460   . creates hierachical name space,
  1461   . now uses normal mixfix annotations (instead of cinfix...),
  1462   . minor changes to some names and values (for consistency),
  1463   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1464   . separator between mutual domain defs: changed "," to "and",
  1465   . improved handling of sort constraints;  now they have to
  1466     appear on the left-hand side of the equations only;
  1467 
  1468 * fixed LAM <x,y,zs>.b syntax;
  1469 
  1470 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1471 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1472 
  1473 
  1474 *** FOL and ZF ***
  1475 
  1476 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1477   with `addloop' of the simplifier to faciliate case splitting in premises.
  1478 
  1479 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1480 in HOL, they strip ALL and --> from proved theorems;
  1481 
  1482 
  1483 
  1484 New in Isabelle94-8 (May 1997)
  1485 ------------------------------
  1486 
  1487 *** General Changes ***
  1488 
  1489 * new utilities to build / run / maintain Isabelle etc. (in parts
  1490 still somewhat experimental); old Makefiles etc. still functional;
  1491 
  1492 * new 'Isabelle System Manual';
  1493 
  1494 * INSTALL text, together with ./configure and ./build scripts;
  1495 
  1496 * reimplemented type inference for greater efficiency, better error
  1497 messages and clean internal interface;
  1498 
  1499 * prlim command for dealing with lots of subgoals (an easier way of
  1500 setting goals_limit);
  1501 
  1502 
  1503 *** Syntax ***
  1504 
  1505 * supports alternative (named) syntax tables (parser and pretty
  1506 printer); internal interface is provided by add_modesyntax(_i);
  1507 
  1508 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1509 be used in conjunction with the Isabelle symbol font; uses the
  1510 "symbols" syntax table;
  1511 
  1512 * added token_translation interface (may translate name tokens in
  1513 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1514 the current print_mode); IMPORTANT: user print translation functions
  1515 are responsible for marking newly introduced bounds
  1516 (Syntax.mark_boundT);
  1517 
  1518 * token translations for modes "xterm" and "xterm_color" that display
  1519 names in bold, underline etc. or colors (which requires a color
  1520 version of xterm);
  1521 
  1522 * infixes may now be declared with names independent of their syntax;
  1523 
  1524 * added typed_print_translation (like print_translation, but may
  1525 access type of constant);
  1526 
  1527 
  1528 *** Classical Reasoner ***
  1529 
  1530 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1531 some limitations.  Blast_tac...
  1532   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1533   + ignores elimination rules that don't have the correct format
  1534         (the conclusion MUST be a formula variable)
  1535   + ignores types, which can make HOL proofs fail
  1536   + rules must not require higher-order unification, e.g. apply_type in ZF
  1537     [message "Function Var's argument not a bound variable" relates to this]
  1538   + its proof strategy is more general but can actually be slower
  1539 
  1540 * substitution with equality assumptions no longer permutes other
  1541 assumptions;
  1542 
  1543 * minor changes in semantics of addafter (now called addaltern); renamed
  1544 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1545 (and access functions for it);
  1546 
  1547 * improved combination of classical reasoner and simplifier:
  1548   + functions for handling clasimpsets
  1549   + improvement of addss: now the simplifier is called _after_ the
  1550     safe steps.
  1551   + safe variant of addss called addSss: uses safe simplifications
  1552     _during_ the safe steps. It is more complete as it allows multiple
  1553     instantiations of unknowns (e.g. with slow_tac).
  1554 
  1555 *** Simplifier ***
  1556 
  1557 * added interface for simplification procedures (functions that
  1558 produce *proven* rewrite rules on the fly, depending on current
  1559 redex);
  1560 
  1561 * ordering on terms as parameter (used for ordered rewriting);
  1562 
  1563 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1564 
  1565 * the solver is now split into a safe and an unsafe part.
  1566 This should be invisible for the normal user, except that the
  1567 functions setsolver and addsolver have been renamed to setSolver and
  1568 addSolver; added safe_asm_full_simp_tac;
  1569 
  1570 
  1571 *** HOL ***
  1572 
  1573 * a generic induction tactic `induct_tac' which works for all datatypes and
  1574 also for type `nat';
  1575 
  1576 * a generic case distinction tactic `exhaust_tac' which works for all
  1577 datatypes and also for type `nat';
  1578 
  1579 * each datatype comes with a function `size';
  1580 
  1581 * patterns in case expressions allow tuple patterns as arguments to
  1582 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1583 
  1584 * primrec now also works with type nat;
  1585 
  1586 * recdef: a new declaration form, allows general recursive functions to be
  1587 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1588 
  1589 * the constant for negation has been renamed from "not" to "Not" to
  1590 harmonize with FOL, ZF, LK, etc.;
  1591 
  1592 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1593 infinite lists;
  1594 
  1595 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1596 
  1597 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1598 problems in commutative rings, using axiomatic type classes for + and *;
  1599 
  1600 * more examples in HOL/MiniML and HOL/Auth;
  1601 
  1602 * more default rewrite rules for quantifiers, union/intersection;
  1603 
  1604 * a new constant `arbitrary == @x.False';
  1605 
  1606 * HOLCF/IOA replaces old HOL/IOA;
  1607 
  1608 * HOLCF changes: derived all rules and arities
  1609   + axiomatic type classes instead of classes
  1610   + typedef instead of faking type definitions
  1611   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1612   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1613   + eliminated the types void, one, tr
  1614   + use unit lift and bool lift (with translations) instead of one and tr
  1615   + eliminated blift from Lift3.thy (use Def instead of blift)
  1616   all eliminated rules are derived as theorems --> no visible changes ;
  1617 
  1618 
  1619 *** ZF ***
  1620 
  1621 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1622 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1623 as ZF_cs addSIs [equalityI];
  1624 
  1625 
  1626 
  1627 New in Isabelle94-7 (November 96)
  1628 ---------------------------------
  1629 
  1630 * allowing negative levels (as offsets) in prlev and choplev;
  1631 
  1632 * super-linear speedup for large simplifications;
  1633 
  1634 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1635 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1636 FAIL); can suppress it using the command Delsimps (ex_simps @
  1637 all_simps); De Morgan laws are also now included, by default;
  1638 
  1639 * improved printing of ==>  :  ~:
  1640 
  1641 * new object-logic "Sequents" adds linear logic, while replacing LK
  1642 and Modal (thanks to Sara Kalvala);
  1643 
  1644 * HOL/Auth: correctness proofs for authentication protocols;
  1645 
  1646 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1647 examples on HOL/Auth);
  1648 
  1649 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1650 the rewriter and classical reasoner simultaneously;
  1651 
  1652 * function uresult no longer returns theorems in "standard" format;
  1653 regain previous version by: val uresult = standard o uresult;
  1654 
  1655 
  1656 
  1657 New in Isabelle94-6
  1658 -------------------
  1659 
  1660 * oracles -- these establish an interface between Isabelle and trusted
  1661 external reasoners, which may deliver results as theorems;
  1662 
  1663 * proof objects (in particular record all uses of oracles);
  1664 
  1665 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1666 
  1667 * "constdefs" section in theory files;
  1668 
  1669 * "primrec" section (HOL) no longer requires names;
  1670 
  1671 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1672 
  1673 
  1674 
  1675 New in Isabelle94-5
  1676 -------------------
  1677 
  1678 * reduced space requirements;
  1679 
  1680 * automatic HTML generation from theories;
  1681 
  1682 * theory files no longer require "..." (quotes) around most types;
  1683 
  1684 * new examples, including two proofs of the Church-Rosser theorem;
  1685 
  1686 * non-curried (1994) version of HOL is no longer distributed;
  1687 
  1688 
  1689 
  1690 New in Isabelle94-4
  1691 -------------------
  1692 
  1693 * greatly reduced space requirements;
  1694 
  1695 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1696 
  1697 * searchable theorem database (see the section "Retrieving theorems" on
  1698 page 8 of the Reference Manual);
  1699 
  1700 * new examples, including Grabczewski's monumental case study of the
  1701 Axiom of Choice;
  1702 
  1703 * The previous version of HOL renamed to Old_HOL;
  1704 
  1705 * The new version of HOL (previously called CHOL) uses a curried syntax
  1706 for functions.  Application looks like f a b instead of f(a,b);
  1707 
  1708 * Mutually recursive inductive definitions finally work in HOL;
  1709 
  1710 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1711 translates to the operator "split";
  1712 
  1713 
  1714 
  1715 New in Isabelle94-3
  1716 -------------------
  1717 
  1718 * new infix operator, addss, allowing the classical reasoner to
  1719 perform simplification at each step of its search.  Example:
  1720         fast_tac (cs addss ss)
  1721 
  1722 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1723 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1724 look like (a,b) instead of <a,b>;
  1725 
  1726 * PLEASE NOTE: CHOL will eventually replace HOL!
  1727 
  1728 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1729 It translates to the operator "split".  A new theory of integers is available;
  1730 
  1731 * In ZF, integer numerals now denote two's-complement binary integers.
  1732 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1733 
  1734 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1735 of the Axiom of Choice;
  1736 
  1737 
  1738 
  1739 New in Isabelle94-2
  1740 -------------------
  1741 
  1742 * Significantly faster resolution;
  1743 
  1744 * the different sections in a .thy file can now be mixed and repeated
  1745 freely;
  1746 
  1747 * Database of theorems for FOL, HOL and ZF.  New
  1748 commands including qed, qed_goal and bind_thm store theorems in the database.
  1749 
  1750 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1751 a given theory (thms_of), or find out what theory a theorem was proved in
  1752 (theory_of_thm);
  1753 
  1754 * Bugs fixed in the inductive definition and datatype packages;
  1755 
  1756 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1757 and HOL_dup_cs obsolete;
  1758 
  1759 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1760 have been removed;
  1761 
  1762 * Simpler definition of function space in ZF;
  1763 
  1764 * new results about cardinal and ordinal arithmetic in ZF;
  1765 
  1766 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1767 types;
  1768 
  1769 
  1770 $Id$