NEWS
author wenzelm
Tue Jan 23 18:05:53 2001 +0100 (2001-01-23)
changeset 10966 8f2c27041a8e
parent 10944 710ddb9e8b5e
child 10976 0e7cf6f9fa29
permissions -rw-r--r--
added HOL-Unix example;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 *** Overview of INCOMPATIBILITIES ***
     6 
     7 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
     8 operation;
     9 
    10 * HOL: induct renamed to lfp_induct;
    11 
    12 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
    13 
    14 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
    15 relation); infix "^^" has been renamed "``"; infix "``" has been
    16 renamed "`"; "univalent" has been renamed "single_valued";
    17 
    18 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
    19 
    20 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
    21 
    22 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
    23 consequence, it is no longer monotonic wrt. the local goal context
    24 (which is now passed through the inductive cases);
    25 
    26 
    27 *** Document preparation ***
    28 
    29 * improved isabelle style files; more abstract symbol implementation
    30 (should now use \isamath{...} and \isatext{...} in custom symbol
    31 definitions);
    32 
    33 * \isabellestyle{NAME} selects version of Isabelle output (currently
    34 available: are "it" for near math-mode best-style output, "sl" for
    35 slanted text style, and "tt" for plain type-writer; if no
    36 \isabellestyle command is given, output is according to slanted
    37 type-writer);
    38 
    39 * support sub/super scripts (for single symbols only), input syntax is
    40 like this: "A\<^sup>*" or "A\<^sup>\<star>";
    41 
    42 * some more standard symbols; see Appendix A of the system manual for
    43 the complete list;
    44 
    45 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
    46 state; Note that presentation of goal states does not conform to
    47 actual human-readable proof documents.  Please do not include goal
    48 states into document output unless you really know what you are doing!
    49 
    50 * isatool unsymbolize tunes sources for plain ASCII communication;
    51 
    52 
    53 *** Isar ***
    54 
    55 * Pure: Isar now suffers initial goal statements to contain unbound
    56 schematic variables (this does not conform to actual readable proof
    57 documents, due to unpredictable outcome and non-compositional proof
    58 checking); users who know what they are doing may use schematic goals
    59 for Prolog-style synthesis of proven results;
    60 
    61 * Pure: assumption method (an implicit finishing) now handles actual
    62 rules as well;
    63 
    64 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
    65 initial goal, declare "that" only as Pure intro (only for single
    66 steps); the "that" rule assumption may now be involved in implicit
    67 finishing, thus ".." becomes a feasible for trivial obtains;
    68 
    69 * Pure: default proof step now includes 'intro_classes'; thus trivial
    70 instance proofs may be performed by "..";
    71 
    72 * Pure: ?thesis / ?this / "..." now work for pure meta-level
    73 statements as well;
    74 
    75 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
    76 rule (as well as the assumption rule);
    77 
    78 * Pure: 'thm_deps' command visualizes dependencies of theorems and
    79 lemmas, using the graph browser tool;
    80 
    81 * Pure: predict failure of "show" in interactive mode;
    82 
    83 * HOL: improved method 'induct' --- now handles non-atomic goals
    84 (potential INCOMPATIBILITY); tuned error handling;
    85 
    86 * HOL: cases and induct rules now provide explicit hints about the
    87 number of facts to be consumed (0 for "type" and 1 for "set" rules);
    88 any remaining facts are inserted into the goal verbatim;
    89 
    90 * HOL: local contexts (aka cases) may now contain term bindings as
    91 well; the 'cases' and 'induct' methods new provide a ?case binding for
    92 the result to be shown in each case;
    93 
    94 * HOL: added 'recdef_tc' command;
    95 
    96 
    97 *** HOL ***
    98 
    99 * HOL/Library: a collection of generic theories to be used together
   100 with main HOL; the theory loader path already includes this directory
   101 by default; the following existing theories have been moved here:
   102 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   103 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   104 
   105 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   106 modelling and verification task performed in Isabelle/HOL +
   107 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   108 
   109 * HOL basics: added overloaded operations "inverse" and "divide"
   110 (infix "/"), syntax for generic "abs" operation, generic summation
   111 operator;
   112 
   113 * HOL/typedef: simplified package, provide more useful rules (see also
   114 HOL/subset.thy);
   115 
   116 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   117 now expressed as a proper nested rule (old-style tactic scripts may
   118 require atomize_strip_tac to cope with non-atomic premises);
   119 
   120 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   121 to "split_conv" (old name still available for compatibility);
   122 
   123 * HOL: improved concrete syntax for strings (e.g. allows translation
   124 rules with string literals);
   125 
   126 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   127 and Fleuriot's mechanization of analysis;
   128 
   129 * HOL-Real, HOL-Hyperreals: improved arithmetic simplification;
   130 
   131 
   132 *** CTT ***
   133 
   134 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   135 "lam" is displayed as TWO lambda-symbols
   136 
   137 * CTT: theory Main now available, containing everything (that is, Bool
   138 and Arith);
   139 
   140 
   141 *** General ***
   142 
   143 * print modes "brackets" and "no_brackets" control output of nested =>
   144 (types) and ==> (props); the default behaviour is "brackets";
   145 
   146 * system: support Poly/ML 4.0 (current beta versions);
   147 
   148 * Pure: the Simplifier has been implemented properly as a derived rule
   149 outside of the actual kernel (at last!); the overall performance
   150 penalty in practical applications is about 50%, while reliability of
   151 the Isabelle inference kernel has been greatly improved;
   152 
   153 * Provers: fast_tac (and friends) now handle actual object-logic rules
   154 as assumptions as well;
   155 
   156 
   157 
   158 New in Isabelle99-1 (October 2000)
   159 ----------------------------------
   160 
   161 *** Overview of INCOMPATIBILITIES ***
   162 
   163 * HOL: simplification of natural numbers is much changed; to partly
   164 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   165 issue the following ML commands:
   166 
   167   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   168   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   169 
   170 * HOL: simplification no longer dives into case-expressions; this is
   171 controlled by "t.weak_case_cong" for each datatype t;
   172 
   173 * HOL: nat_less_induct renamed to less_induct;
   174 
   175 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   176 fixsome to patch .thy and .ML sources automatically;
   177 
   178   select_equality  -> some_equality
   179   select_eq_Ex     -> some_eq_ex
   180   selectI2EX       -> someI2_ex
   181   selectI2         -> someI2
   182   selectI          -> someI
   183   select1_equality -> some1_equality
   184   Eps_sym_eq       -> some_sym_eq_trivial
   185   Eps_eq           -> some_eq_trivial
   186 
   187 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   188 
   189 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   190 instead);
   191 
   192 * HOL: the recursion equations generated by 'recdef' are now called
   193 f.simps instead of f.rules;
   194 
   195 * HOL: qed_spec_mp now also handles bounded ALL as well;
   196 
   197 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   198 sometimes be needed;
   199 
   200 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   201 
   202 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   203 
   204 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   205 product is now "<*>" instead of "Times"; the lexicographic product is
   206 now "<*lex*>" instead of "**";
   207 
   208 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   209 of main HOL, but was unused); better use HOL's datatype package;
   210 
   211 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   212 the old syntax may be recovered as follows:
   213 
   214   syntax (symbols)
   215     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   216       (infixl "\\<oplus>" 100)
   217 
   218 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   219 
   220 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   221 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   222 internally;
   223 
   224 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   225 changed from A/r to A//r;
   226 
   227 * ZF: new treatment of arithmetic (nat & int) may break some old
   228 proofs;
   229 
   230 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   231 rulify -> rule_format, elimify -> elim_format, ...);
   232 
   233 * Isar/Provers: intro/elim/dest attributes changed; renamed
   234 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   235 should have to change intro!! to intro? only); replaced "delrule" by
   236 "rule del";
   237 
   238 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   239 
   240 * Provers: strengthened force_tac by using new first_best_tac;
   241 
   242 * LaTeX document preparation: several changes of isabelle.sty (see
   243 lib/texinputs);
   244 
   245 
   246 *** Document preparation ***
   247 
   248 * formal comments (text blocks etc.) in new-style theories may now
   249 contain antiquotations of thm/prop/term/typ/text to be presented
   250 according to latex print mode; concrete syntax is like this:
   251 @{term[show_types] "f(x) = a + x"};
   252 
   253 * isatool mkdir provides easy setup of Isabelle session directories,
   254 including proper document sources;
   255 
   256 * generated LaTeX sources are now deleted after successful run
   257 (isatool document -c); may retain a copy somewhere else via -D option
   258 of isatool usedir;
   259 
   260 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   261 style files, achieving self-contained LaTeX sources and simplifying
   262 LaTeX debugging;
   263 
   264 * old-style theories now produce (crude) LaTeX output as well;
   265 
   266 * browser info session directories are now self-contained (may be put
   267 on WWW server seperately); improved graphs of nested sessions; removed
   268 graph for 'all sessions';
   269 
   270 * several improvements in isabelle style files; \isabellestyle{it}
   271 produces fake math mode output; \isamarkupheader is now \section by
   272 default; see lib/texinputs/isabelle.sty etc.;
   273 
   274 
   275 *** Isar ***
   276 
   277 * Isar/Pure: local results and corresponding term bindings are now
   278 subject to Hindley-Milner polymorphism (similar to ML); this
   279 accommodates incremental type-inference very nicely;
   280 
   281 * Isar/Pure: new derived language element 'obtain' supports
   282 generalized existence reasoning;
   283 
   284 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   285 support accumulation of results, without applying any rules yet;
   286 useful to collect intermediate results without explicit name
   287 references, and for use with transitivity rules with more than 2
   288 premises;
   289 
   290 * Isar/Pure: scalable support for case-analysis type proofs: new
   291 'case' language element refers to local contexts symbolically, as
   292 produced by certain proof methods; internally, case names are attached
   293 to theorems as "tags";
   294 
   295 * Isar/Pure: theory command 'hide' removes declarations from
   296 class/type/const name spaces;
   297 
   298 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   299 indicate potential overloading;
   300 
   301 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   302 
   303 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   304 "{a,b,c}" instead of {a,b,c};
   305 
   306 * Isar/Pure now provides its own version of intro/elim/dest
   307 attributes; useful for building new logics, but beware of confusion
   308 with the version in Provers/classical;
   309 
   310 * Isar/Pure: the local context of (non-atomic) goals is provided via
   311 case name 'antecedent';
   312 
   313 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   314 to the current context is now done automatically);
   315 
   316 * Isar/Pure: theory command 'method_setup' provides a simple interface
   317 for definining proof methods in ML;
   318 
   319 * Isar/Provers: intro/elim/dest attributes changed; renamed
   320 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   321 most cases, one should have to change intro!! to intro? only);
   322 replaced "delrule" by "rule del";
   323 
   324 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   325 'symmetric' attribute (the latter supercedes [RS sym]);
   326 
   327 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   328 method modifier); 'simp' method: 'only:' modifier removes loopers as
   329 well (including splits);
   330 
   331 * Isar/Provers: Simplifier and Classical methods now support all kind
   332 of modifiers used in the past, including 'cong', 'iff', etc.
   333 
   334 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   335 of Simplifier and Classical reasoner);
   336 
   337 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   338 now support named cases; major packages (inductive, datatype, primrec,
   339 recdef) support case names and properly name parameters;
   340 
   341 * Isar/HOL: new transitivity rules for substitution in inequalities --
   342 monotonicity conditions are extracted to be proven at end of
   343 calculations;
   344 
   345 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   346 method anyway;
   347 
   348 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   349 split_if split_if_asm; datatype package provides theorems foo.splits =
   350 foo.split foo.split_asm for each datatype;
   351 
   352 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   353 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   354 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   355 use "(cases (simplified))" method in proper proof texts);
   356 
   357 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   358 
   359 * Isar: names of theorems etc. may be natural numbers as well;
   360 
   361 * Isar: 'pr' command: optional arguments for goals_limit and
   362 ProofContext.prems_limit; no longer prints theory contexts, but only
   363 proof states;
   364 
   365 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   366 additional print modes to be specified; e.g. "pr(latex)" will print
   367 proof state according to the Isabelle LaTeX style;
   368 
   369 * Isar: improved support for emulating tactic scripts, including proof
   370 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   371 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   372 (for HOL datatypes);
   373 
   374 * Isar: simplified (more robust) goal selection of proof methods: 1st
   375 goal, all goals, or explicit goal specifier (tactic emulation); thus
   376 'proof method scripts' have to be in depth-first order;
   377 
   378 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   379 
   380 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   381 should instead use individual commands for printing items
   382 (print_commands, print_methods etc.);
   383 
   384 * Isar: added 'nothing' --- the empty list of theorems;
   385 
   386 
   387 *** HOL ***
   388 
   389 * HOL/MicroJava: formalization of a fragment of Java, together with a
   390 corresponding virtual machine and a specification of its bytecode
   391 verifier and a lightweight bytecode verifier, including proofs of
   392 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   393 Cornelia Pusch (see also the homepage of project Bali at
   394 http://isabelle.in.tum.de/Bali/);
   395 
   396 * HOL/Algebra: new theory of rings and univariate polynomials, by
   397 Clemens Ballarin;
   398 
   399 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   400 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   401 Rasmussen;
   402 
   403 * HOL/Lattice: fundamental concepts of lattice theory and order
   404 structures, including duals, properties of bounds versus algebraic
   405 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   406 Theorem for complete lattices etc.; may also serve as a demonstration
   407 for abstract algebraic reasoning using axiomatic type classes, and
   408 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   409 
   410 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   411 von Oheimb;
   412 
   413 * HOL/IMPP: extension of IMP with local variables and mutually
   414 recursive procedures, by David von Oheimb;
   415 
   416 * HOL/Lambda: converted into new-style theory and document;
   417 
   418 * HOL/ex/Multiquote: example of multiple nested quotations and
   419 anti-quotations -- basically a generalized version of de-Bruijn
   420 representation; very useful in avoiding lifting of operations;
   421 
   422 * HOL/record: added general record equality rule to simpset; fixed
   423 select-update simplification procedure to handle extended records as
   424 well; admit "r" as field name;
   425 
   426 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   427 other numeric types and also as the identity of groups, rings, etc.;
   428 
   429 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   430 Types nat and int belong to this axclass;
   431 
   432 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   433    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   434    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   435   two terms #m*u and #n*u are replaced by #(m+n)*u
   436     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   437   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   438     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   439 
   440 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   441 powerful prover for predicate logic but knows nothing of clasets; see
   442 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   443 
   444 * HOL: new version of "case_tac" subsumes both boolean case split and
   445 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   446 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   447 
   448 * HOL: simplification no longer dives into case-expressions: only the
   449 selector expression is simplified, but not the remaining arms; to
   450 enable full simplification of case-expressions for datatype t, you may
   451 remove t.weak_case_cong from the simpset, either globally (Delcongs
   452 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   453 
   454 * HOL/recdef: the recursion equations generated by 'recdef' for
   455 function 'f' are now called f.simps instead of f.rules; if all
   456 termination conditions are proved automatically, these simplification
   457 rules are added to the simpset, as in primrec; rules may be named
   458 individually as well, resulting in a separate list of theorems for
   459 each equation;
   460 
   461 * HOL/While is a new theory that provides a while-combinator. It
   462 permits the definition of tail-recursive functions without the
   463 provision of a termination measure. The latter is necessary once the
   464 invariant proof rule for while is applied.
   465 
   466 * HOL: new (overloaded) notation for the set of elements below/above
   467 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   468 
   469 * HOL: theorems impI, allI, ballI bound as "strip";
   470 
   471 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   472 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   473 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   474 
   475 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   476 
   477 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   478 main HOL, but was unused);
   479 
   480 * HOL: fewer consts declared as global (e.g. have to refer to
   481 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   482 
   483 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   484 in case of overlap with user translations (e.g. judgements over
   485 tuples); (note that the underlying logical represenation is still
   486 bogus);
   487 
   488 
   489 *** ZF ***
   490 
   491 * ZF: simplification automatically cancels common terms in arithmetic
   492 expressions over nat and int;
   493 
   494 * ZF: new treatment of nat to minimize type-checking: all operators
   495 coerce their operands to a natural number using the function natify,
   496 making the algebraic laws unconditional;
   497 
   498 * ZF: as above, for int: operators coerce their operands to an integer
   499 using the function intify;
   500 
   501 * ZF: the integer library now contains many of the usual laws for the
   502 orderings, including $<=, and monotonicity laws for $+ and $*;
   503 
   504 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   505 simplification;
   506 
   507 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   508 to the simplifier and classical reasoner simultaneously;
   509 
   510 
   511 *** General ***
   512 
   513 * Provers: blast_tac now handles actual object-logic rules as
   514 assumptions; note that auto_tac uses blast_tac internally as well;
   515 
   516 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   517 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   518 
   519 * Provers: delrules now handles destruct rules as well (no longer need
   520 explicit make_elim);
   521 
   522 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   523   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   524 use instead the strong form,
   525   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   526 in HOL, FOL and ZF the function cla_make_elim will create such rules
   527 from destruct-rules;
   528 
   529 * Provers: Simplifier.easy_setup provides a fast path to basic
   530 Simplifier setup for new object-logics;
   531 
   532 * Pure: AST translation rules no longer require constant head on LHS;
   533 
   534 * Pure: improved name spaces: ambiguous output is qualified; support
   535 for hiding of names;
   536 
   537 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   538 XSYMBOL_HOME; no longer need to do manual configuration in most
   539 situations;
   540 
   541 * system: compression of ML heaps images may now be controlled via -c
   542 option of isabelle and isatool usedir (currently only observed by
   543 Poly/ML);
   544 
   545 * system: isatool installfonts may handle X-Symbol fonts as well (very
   546 useful for remote X11);
   547 
   548 * system: provide TAGS file for Isabelle sources;
   549 
   550 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   551 order;
   552 
   553 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   554 timing flag supersedes proof_timing and Toplevel.trace;
   555 
   556 * ML: new combinators |>> and |>>> for incremental transformations
   557 with secondary results (e.g. certain theory extensions):
   558 
   559 * ML: PureThy.add_defs gets additional argument to indicate potential
   560 overloading (usually false);
   561 
   562 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   563 results;
   564 
   565 
   566 
   567 New in Isabelle99 (October 1999)
   568 --------------------------------
   569 
   570 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   571 
   572 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   573 are no longer simplified.  (This allows the simplifier to unfold recursive
   574 functional programs.)  To restore the old behaviour, declare
   575 
   576     Delcongs [if_weak_cong];
   577 
   578 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   579 complement;
   580 
   581 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   582 
   583 * HOL/datatype: mutual_induct_tac no longer exists --
   584   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   585 
   586 * HOL/typedef: fixed type inference for representing set; type
   587 arguments now have to occur explicitly on the rhs as type constraints;
   588 
   589 * ZF: The con_defs part of an inductive definition may no longer refer
   590 to constants declared in the same theory;
   591 
   592 * HOL, ZF: the function mk_cases, generated by the inductive
   593 definition package, has lost an argument.  To simplify its result, it
   594 uses the default simpset instead of a supplied list of theorems.
   595 
   596 * HOL/List: the constructors of type list are now Nil and Cons;
   597 
   598 * Simplifier: the type of the infix ML functions
   599         setSSolver addSSolver setSolver addSolver
   600 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   601 for packaging solvers. A solver is created via
   602         mk_solver: string -> (thm list -> int -> tactic) -> solver
   603 where the string argument is only a comment.
   604 
   605 
   606 *** Proof tools ***
   607 
   608 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   609 decision procedure for linear arithmetic. Currently it is used for
   610 types `nat', `int', and `real' in HOL (see below); it can, should and
   611 will be instantiated for other types and logics as well.
   612 
   613 * The simplifier now accepts rewrite rules with flexible heads, eg
   614      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   615   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   616   matching.
   617 
   618 
   619 *** General ***
   620 
   621 * New Isabelle/Isar subsystem provides an alternative to traditional
   622 tactical theorem proving; together with the ProofGeneral/isar user
   623 interface it offers an interactive environment for developing human
   624 readable proof documents (Isar == Intelligible semi-automated
   625 reasoning); for further information see isatool doc isar-ref,
   626 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   627 
   628 * improved and simplified presentation of theories: better HTML markup
   629 (including colors), graph views in several sizes; isatool usedir now
   630 provides a proper interface for user theories (via -P option); actual
   631 document preparation based on (PDF)LaTeX is available as well (for
   632 new-style theories only); see isatool doc system for more information;
   633 
   634 * native support for Proof General, both for classic Isabelle and
   635 Isabelle/Isar;
   636 
   637 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   638 using the graph browser tool;
   639 
   640 * Isabelle manuals now also available as PDF;
   641 
   642 * theory loader rewritten from scratch (may not be fully
   643 bug-compatible); old loadpath variable has been replaced by show_path,
   644 add_path, del_path, reset_path functions; new operations such as
   645 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   646 isatool doc ref);
   647 
   648 * improved isatool install: option -k creates KDE application icon,
   649 option -p DIR installs standalone binaries;
   650 
   651 * added ML_PLATFORM setting (useful for cross-platform installations);
   652 more robust handling of platform specific ML images for SML/NJ;
   653 
   654 * the settings environment is now statically scoped, i.e. it is never
   655 created again in sub-processes invoked from isabelle, isatool, or
   656 Isabelle;
   657 
   658 * path element specification '~~' refers to '$ISABELLE_HOME';
   659 
   660 * in locales, the "assumes" and "defines" parts may be omitted if
   661 empty;
   662 
   663 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   664 long arrows);
   665 
   666 * new print_mode "HTML";
   667 
   668 * new flag show_tags controls display of tags of theorems (which are
   669 basically just comments that may be attached by some tools);
   670 
   671 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   672 mode and goal output format:
   673 
   674 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   675 244c244
   676 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   677 ---
   678 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   679 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   680 181c181
   681 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   682 ---
   683 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   684 
   685 * function bind_thms stores lists of theorems (cf. bind_thm);
   686 
   687 * new shorthand tactics ftac, eatac, datac, fatac;
   688 
   689 * qed (and friends) now accept "" as result name; in that case the
   690 theorem is not stored, but proper checks and presentation of the
   691 result still apply;
   692 
   693 * theorem database now also indexes constants "Trueprop", "all",
   694 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   695 
   696 
   697 *** HOL ***
   698 
   699 ** HOL arithmetic **
   700 
   701 * There are now decision procedures for linear arithmetic over nat and
   702 int:
   703 
   704 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   705 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   706 are treated as atomic; subformulae not involving type `nat' or `int'
   707 are ignored; quantified subformulae are ignored unless they are
   708 positive universal or negative existential. The tactic has to be
   709 invoked by hand and can be a little bit slow. In particular, the
   710 running time is exponential in the number of occurrences of `min' and
   711 `max', and `-' on `nat'.
   712 
   713 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   714 (negated) (in)equalities among the premises and the conclusion into
   715 account (i.e. no compound formulae) and does not know about `min' and
   716 `max', and `-' on `nat'. It is fast and is used automatically by the
   717 simplifier.
   718 
   719 NB: At the moment, these decision procedures do not cope with mixed
   720 nat/int formulae where the two parts interact, such as `m < n ==>
   721 int(m) < int(n)'.
   722 
   723 * HOL/Numeral provides a generic theory of numerals (encoded
   724 efficiently as bit strings); setup for types nat/int/real is in place;
   725 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   726 int, existing theories and proof scripts may require a few additional
   727 type constraints;
   728 
   729 * integer division and remainder can now be performed on constant
   730 arguments;
   731 
   732 * many properties of integer multiplication, division and remainder
   733 are now available;
   734 
   735 * An interface to the Stanford Validity Checker (SVC) is available through the
   736 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   737 are proved automatically.  SVC must be installed separately, and its results
   738 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   739 invocation of the underlying oracle).  For SVC see
   740   http://verify.stanford.edu/SVC
   741 
   742 * IsaMakefile: the HOL-Real target now builds an actual image;
   743 
   744 
   745 ** HOL misc **
   746 
   747 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   748 (in Isabelle/Isar) -- by Gertrud Bauer;
   749 
   750 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   751 analysis for assembly languages with subtypes;
   752 
   753 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   754 -- avoids syntactic ambiguities and treats state, transition, and
   755 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   756 changed syntax and (many) tactics;
   757 
   758 * HOL/inductive: Now also handles more general introduction rules such
   759   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   760   theorems are now maintained within the theory (maintained via the
   761   "mono" attribute);
   762 
   763 * HOL/datatype: Now also handles arbitrarily branching datatypes
   764   (using function types) such as
   765 
   766   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   767 
   768 * HOL/record: record_simproc (part of the default simpset) takes care
   769 of selectors applied to updated records; record_split_tac is no longer
   770 part of the default claset; update_defs may now be removed from the
   771 simpset in many cases; COMPATIBILITY: old behavior achieved by
   772 
   773   claset_ref () := claset() addSWrapper record_split_wrapper;
   774   Delsimprocs [record_simproc]
   775 
   776 * HOL/typedef: fixed type inference for representing set; type
   777 arguments now have to occur explicitly on the rhs as type constraints;
   778 
   779 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   780 names rather than an ML expression;
   781 
   782 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   783 supplied later.  Program schemes can be defined, such as
   784     "While B C s = (if B s then While B C (C s) else s)"
   785 where the well-founded relation can be chosen after B and C have been given.
   786 
   787 * HOL/List: the constructors of type list are now Nil and Cons;
   788 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   789 course, ML tools referring to List.list.op # etc. have to be adapted;
   790 
   791 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   792 disabled by default; run isabelle with option -m HOL to get back to
   793 the original Gordon/HOL-style output;
   794 
   795 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   796 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   797 
   798 * HOL basic syntax simplified (more orthogonal): all variants of
   799 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   800 Eps operator is provided as well: "SOME x. P[x]";
   801 
   802 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   803 
   804 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   805 thus available for user theories;
   806 
   807 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   808 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   809 time;
   810 
   811 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   812 several times and then mp;
   813 
   814 
   815 *** LK ***
   816 
   817 * the notation <<...>> is now available as a notation for sequences of
   818 formulas;
   819 
   820 * the simplifier is now installed
   821 
   822 * the axiom system has been generalized (thanks to Soren Heilmann)
   823 
   824 * the classical reasoner now has a default rule database
   825 
   826 
   827 *** ZF ***
   828 
   829 * new primrec section allows primitive recursive functions to be given
   830 directly (as in HOL) over datatypes and the natural numbers;
   831 
   832 * new tactics induct_tac and exhaust_tac for induction (or case
   833 analysis) over datatypes and the natural numbers;
   834 
   835 * the datatype declaration of type T now defines the recursor T_rec;
   836 
   837 * simplification automatically does freeness reasoning for datatype
   838 constructors;
   839 
   840 * automatic type-inference, with AddTCs command to insert new
   841 type-checking rules;
   842 
   843 * datatype introduction rules are now added as Safe Introduction rules
   844 to the claset;
   845 
   846 * the syntax "if P then x else y" is now available in addition to
   847 if(P,x,y);
   848 
   849 
   850 *** Internal programming interfaces ***
   851 
   852 * tuned simplifier trace output; new flag debug_simp;
   853 
   854 * structures Vartab / Termtab (instances of TableFun) offer efficient
   855 tables indexed by indexname_ord / term_ord (compatible with aconv);
   856 
   857 * AxClass.axclass_tac lost the theory argument;
   858 
   859 * tuned current_goals_markers semantics: begin / end goal avoids
   860 printing empty lines;
   861 
   862 * removed prs and prs_fn hook, which was broken because it did not
   863 include \n in its semantics, forcing writeln to add one
   864 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   865 string -> unit if you really want to output text without newline;
   866 
   867 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   868 plain output, interface builders may have to enable 'isabelle_font'
   869 mode to get Isabelle font glyphs as before;
   870 
   871 * refined token_translation interface; INCOMPATIBILITY: output length
   872 now of type real instead of int;
   873 
   874 * theory loader actions may be traced via new ThyInfo.add_hook
   875 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   876 your own database of information attached to *whole* theories -- as
   877 opposed to intra-theory data slots offered via TheoryDataFun;
   878 
   879 * proper handling of dangling sort hypotheses (at last!);
   880 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   881 extra sort hypotheses that can be witnessed from the type signature;
   882 the force_strip_shyps flag is gone, any remaining shyps are simply
   883 left in the theorem (with a warning issued by strip_shyps_warning);
   884 
   885 
   886 
   887 New in Isabelle98-1 (October 1998)
   888 ----------------------------------
   889 
   890 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   891 
   892 * several changes of automated proof tools;
   893 
   894 * HOL: major changes to the inductive and datatype packages, including
   895 some minor incompatibilities of theory syntax;
   896 
   897 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   898 called `inj_on';
   899 
   900 * HOL: removed duplicate thms in Arith:
   901   less_imp_add_less  should be replaced by  trans_less_add1
   902   le_imp_add_le      should be replaced by  trans_le_add1
   903 
   904 * HOL: unary minus is now overloaded (new type constraints may be
   905 required);
   906 
   907 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   908 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   909 now taken as an integer constant.
   910 
   911 * Pure: ML function 'theory_of' renamed to 'theory';
   912 
   913 
   914 *** Proof tools ***
   915 
   916 * Simplifier:
   917   1. Asm_full_simp_tac is now more aggressive.
   918      1. It will sometimes reorient premises if that increases their power to
   919         simplify.
   920      2. It does no longer proceed strictly from left to right but may also
   921         rotate premises to achieve further simplification.
   922      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   923      old Asm_full_simp_tac in that it does not rotate premises.
   924   2. The simplifier now knows a little bit about nat-arithmetic.
   925 
   926 * Classical reasoner: wrapper mechanism for the classical reasoner now
   927 allows for selected deletion of wrappers, by introduction of names for
   928 wrapper functionals.  This implies that addbefore, addSbefore,
   929 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   930 and that adding two tactics with the same name overwrites the first
   931 one (emitting a warning).
   932   type wrapper = (int -> tactic) -> (int -> tactic)
   933   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   934   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   935   delWrapper, delSWrapper: claset *  string            -> claset
   936   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   937 
   938 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   939 semantics; addbefore now affects only the unsafe part of step_tac
   940 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   941 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   942 by Force_tac;
   943 
   944 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   945 compWrapper; added safe wrapper (and access functions for it);
   946 
   947 * HOL/split_all_tac is now much faster and fails if there is nothing
   948 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   949 and the names of the automatically generated variables have changed.
   950 split_all_tac has moved within claset() from unsafe wrappers to safe
   951 wrappers, which means that !!-bound variables are split much more
   952 aggressively, and safe_tac and clarify_tac now split such variables.
   953 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   954 Note: the same holds for record_split_tac, which does the job of
   955 split_all_tac for record fields.
   956 
   957 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   958 permanently to the default simpset using Addsplits just like
   959 Addsimps. They can be removed via Delsplits just like
   960 Delsimps. Lower-case versions are also available.
   961 
   962 * HOL/Simplifier: The rule split_if is now part of the default
   963 simpset. This means that the simplifier will eliminate all occurrences
   964 of if-then-else in the conclusion of a goal. To prevent this, you can
   965 either remove split_if completely from the default simpset by
   966 `Delsplits [split_if]' or remove it in a specific call of the
   967 simplifier using `... delsplits [split_if]'.  You can also add/delete
   968 other case splitting rules to/from the default simpset: every datatype
   969 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   970 t is the name of the datatype).
   971 
   972 * Classical reasoner / Simplifier combination: new force_tac (and
   973 derivatives Force_tac, force) combines rewriting and classical
   974 reasoning (and whatever other tools) similarly to auto_tac, but is
   975 aimed to solve the given subgoal completely.
   976 
   977 
   978 *** General ***
   979 
   980 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   981 and `goalw': the theory is no longer needed as an explicit argument -
   982 the current theory context is used; assumptions are no longer returned
   983 at the ML-level unless one of them starts with ==> or !!; it is
   984 recommended to convert to these new commands using isatool fixgoal
   985 (backup your sources first!);
   986 
   987 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   988 the current theory context, and 'theory' to lookup stored theories;
   989 
   990 * new theory section 'locale' for declaring constants, assumptions and
   991 definitions that have local scope;
   992 
   993 * new theory section 'nonterminals' for purely syntactic types;
   994 
   995 * new theory section 'setup' for generic ML setup functions
   996 (e.g. package initialization);
   997 
   998 * the distribution now includes Isabelle icons: see
   999 lib/logo/isabelle-{small,tiny}.xpm;
  1000 
  1001 * isatool install - install binaries with absolute references to
  1002 ISABELLE_HOME/bin;
  1003 
  1004 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1005 
  1006 * print mode 'emacs' reserved for Isamode;
  1007 
  1008 * support multiple print (ast) translations per constant name;
  1009 
  1010 * theorems involving oracles are now printed with a suffixed [!];
  1011 
  1012 
  1013 *** HOL ***
  1014 
  1015 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1016 
  1017 * HOL/inductive package reorganized and improved: now supports mutual
  1018 definitions such as
  1019 
  1020   inductive EVEN ODD
  1021     intrs
  1022       null "0 : EVEN"
  1023       oddI "n : EVEN ==> Suc n : ODD"
  1024       evenI "n : ODD ==> Suc n : EVEN"
  1025 
  1026 new theorem list "elims" contains an elimination rule for each of the
  1027 recursive sets; inductive definitions now handle disjunctive premises
  1028 correctly (also ZF);
  1029 
  1030 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1031 "mutual_induct" no longer exists - the induction rule is always
  1032 contained in "induct";
  1033 
  1034 
  1035 * HOL/datatype package re-implemented and greatly improved: now
  1036 supports mutually recursive datatypes such as
  1037 
  1038   datatype
  1039     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1040             | SUM ('a aexp) ('a aexp)
  1041             | DIFF ('a aexp) ('a aexp)
  1042             | NUM 'a
  1043   and
  1044     'a bexp = LESS ('a aexp) ('a aexp)
  1045             | AND ('a bexp) ('a bexp)
  1046             | OR ('a bexp) ('a bexp)
  1047 
  1048 as well as indirectly recursive datatypes such as
  1049 
  1050   datatype
  1051     ('a, 'b) term = Var 'a
  1052                   | App 'b ((('a, 'b) term) list)
  1053 
  1054 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1055 induction on mutually / indirectly recursive datatypes.
  1056 
  1057 Primrec equations are now stored in theory and can be accessed via
  1058 <function_name>.simps.
  1059 
  1060 INCOMPATIBILITIES:
  1061 
  1062   - Theories using datatypes must now have theory Datatype as an
  1063     ancestor.
  1064   - The specific <typename>.induct_tac no longer exists - use the
  1065     generic induct_tac instead.
  1066   - natE has been renamed to nat.exhaust - use exhaust_tac
  1067     instead of res_inst_tac ... natE. Note that the variable
  1068     names in nat.exhaust differ from the names in natE, this
  1069     may cause some "fragile" proofs to fail.
  1070   - The theorems split_<typename>_case and split_<typename>_case_asm
  1071     have been renamed to <typename>.split and <typename>.split_asm.
  1072   - Since default sorts of type variables are now handled correctly,
  1073     some datatype definitions may have to be annotated with explicit
  1074     sort constraints.
  1075   - Primrec definitions no longer require function name and type
  1076     of recursive argument.
  1077 
  1078 Consider using isatool fixdatatype to adapt your theories and proof
  1079 scripts to the new package (backup your sources first!).
  1080 
  1081 
  1082 * HOL/record package: considerably improved implementation; now
  1083 includes concrete syntax for record types, terms, updates; theorems
  1084 for surjective pairing and splitting !!-bound record variables; proof
  1085 support is as follows:
  1086 
  1087   1) standard conversions (selectors or updates applied to record
  1088 constructor terms) are part of the standard simpset;
  1089 
  1090   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1091 made part of standard simpset and claset via addIffs;
  1092 
  1093   3) a tactic for record field splitting (record_split_tac) is part of
  1094 the standard claset (addSWrapper);
  1095 
  1096 To get a better idea about these rules you may retrieve them via
  1097 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1098 the name of your record type.
  1099 
  1100 The split tactic 3) conceptually simplifies by the following rule:
  1101 
  1102   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1103 
  1104 Thus any record variable that is bound by meta-all will automatically
  1105 blow up into some record constructor term, consequently the
  1106 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1107 solve record problems automatically.
  1108 
  1109 
  1110 * reorganized the main HOL image: HOL/Integ and String loaded by
  1111 default; theory Main includes everything;
  1112 
  1113 * automatic simplification of integer sums and comparisons, using cancellation;
  1114 
  1115 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1116 
  1117 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1118 
  1119 * many new identities for unions, intersections, set difference, etc.;
  1120 
  1121 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1122 called split_if, split_split, split_sum_case and split_nat_case (to go
  1123 with add/delsplits);
  1124 
  1125 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1126 (?x::unit) = (); this is made part of the default simpset, which COULD
  1127 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1128 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1129 unit_abs_eta_conv is added in order to counter the effect of
  1130 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1131 %u.f();
  1132 
  1133 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1134 makes more sense);
  1135 
  1136 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1137   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1138   disjointness reasoning but breaking a few old proofs.
  1139 
  1140 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1141 to 'converse' from 'inverse' (for compatibility with ZF and some
  1142 literature);
  1143 
  1144 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1145 the well-founded relation;
  1146 
  1147 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1148     Compl A.  The "Compl" syntax remains available as input syntax for this
  1149     release ONLY.
  1150 
  1151 * HOL/Update: new theory of function updates:
  1152     f(a:=b) == %x. if x=a then b else f x
  1153 may also be iterated as in f(a:=b,c:=d,...);
  1154 
  1155 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1156 
  1157 * HOL/List:
  1158   - new function list_update written xs[i:=v] that updates the i-th
  1159     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1160   - new function `upt' written [i..j(] which generates the list
  1161     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1162     bound write [i..j], which is a shorthand for [i..j+1(].
  1163   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1164 
  1165 * HOL/Arith:
  1166   - removed 'pred' (predecessor) function;
  1167   - generalized some theorems about n-1;
  1168   - many new laws about "div" and "mod";
  1169   - new laws about greatest common divisors (see theory ex/Primes);
  1170 
  1171 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1172 instead of "inverse";
  1173 
  1174 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1175   of the multiset ordering;
  1176 
  1177 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1178   (not included by default);
  1179 
  1180 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1181 
  1182 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1183   programs, i.e. different program variables may have different types.
  1184 
  1185 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1186   [previously, this check worked only if the rewrite rule was unconditional]
  1187   Now rew can involve either definitions or equalities (either == or =).
  1188 
  1189 
  1190 *** ZF ***
  1191 
  1192 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1193   only the theorems proved on ZF.ML;
  1194 
  1195 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1196   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1197   disjointness reasoning but breaking a few old proofs.
  1198 
  1199 * ZF/Update: new theory of function updates
  1200     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1201   may also be iterated as in f(a:=b,c:=d,...);
  1202 
  1203 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1204 
  1205 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1206   [previously, this check worked only if the rewrite rule was unconditional]
  1207   Now rew can involve either definitions or equalities (either == or =).
  1208 
  1209 * case_tac provided for compatibility with HOL
  1210     (like the old excluded_middle_tac, but with subgoals swapped)
  1211 
  1212 
  1213 *** Internal programming interfaces ***
  1214 
  1215 * Pure: several new basic modules made available for general use, see
  1216 also src/Pure/README;
  1217 
  1218 * improved the theory data mechanism to support encapsulation (data
  1219 kind name replaced by private Object.kind, acting as authorization
  1220 key); new type-safe user interface via functor TheoryDataFun; generic
  1221 print_data function becomes basically useless;
  1222 
  1223 * removed global_names compatibility flag -- all theory declarations
  1224 are qualified by default;
  1225 
  1226 * module Pure/Syntax now offers quote / antiquote translation
  1227 functions (useful for Hoare logic etc. with implicit dependencies);
  1228 see HOL/ex/Antiquote for an example use;
  1229 
  1230 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1231 cterm -> thm;
  1232 
  1233 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1234 subgoal;
  1235 
  1236 * Display.print_goals function moved to Locale.print_goals;
  1237 
  1238 * standard print function for goals supports current_goals_markers
  1239 variable for marking begin of proof, end of proof, start of goal; the
  1240 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1241 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1242 for example;
  1243 
  1244 
  1245 
  1246 New in Isabelle98 (January 1998)
  1247 --------------------------------
  1248 
  1249 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1250 
  1251 * changed lexical syntax of terms / types: dots made part of long
  1252 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1253 
  1254 * simpset (and claset) reference variable replaced by functions
  1255 simpset / simpset_ref;
  1256 
  1257 * no longer supports theory aliases (via merge) and non-trivial
  1258 implicit merge of thms' signatures;
  1259 
  1260 * most internal names of constants changed due to qualified names;
  1261 
  1262 * changed Pure/Sequence interface (see Pure/seq.ML);
  1263 
  1264 
  1265 *** General Changes ***
  1266 
  1267 * hierachically structured name spaces (for consts, types, axms, thms
  1268 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1269 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1270 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1271 long_names for fully qualified output names; NOTE: ML programs
  1272 (special tactics, packages etc.) referring to internal names may have
  1273 to be adapted to cope with fully qualified names; in case of severe
  1274 backward campatibility problems try setting 'global_names' at compile
  1275 time to have enrything declared within a flat name space; one may also
  1276 fine tune name declarations in theories via the 'global' and 'local'
  1277 section;
  1278 
  1279 * reimplemented the implicit simpset and claset using the new anytype
  1280 data filed in signatures; references simpset:simpset ref etc. are
  1281 replaced by functions simpset:unit->simpset and
  1282 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1283 to patch your ML files accordingly;
  1284 
  1285 * HTML output now includes theory graph data for display with Java
  1286 applet or isatool browser; data generated automatically via isatool
  1287 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1288 
  1289 * defs may now be conditional; improved rewrite_goals_tac to handle
  1290 conditional equations;
  1291 
  1292 * defs now admits additional type arguments, using TYPE('a) syntax;
  1293 
  1294 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1295 creates a new theory node; implicit merge of thms' signatures is
  1296 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1297 transfer:theory->thm->thm in (rare) cases;
  1298 
  1299 * improved handling of draft signatures / theories; draft thms (and
  1300 ctyps, cterms) are automatically promoted to real ones;
  1301 
  1302 * slightly changed interfaces for oracles: admit many per theory, named
  1303 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1304 
  1305 * print_goals: optional output of const types (set show_consts and
  1306 show_types);
  1307 
  1308 * improved output of warnings (###) and errors (***);
  1309 
  1310 * subgoal_tac displays a warning if the new subgoal has type variables;
  1311 
  1312 * removed old README and Makefiles;
  1313 
  1314 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1315 
  1316 * removed obsolete init_pps and init_database;
  1317 
  1318 * deleted the obsolete tactical STATE, which was declared by
  1319     fun STATE tacfun st = tacfun st st;
  1320 
  1321 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1322 (which abbreviates $HOME);
  1323 
  1324 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1325 use isatool fixseq to adapt your ML programs (this works for fully
  1326 qualified references to the Sequence structure only!);
  1327 
  1328 * use_thy no longer requires writable current directory; it always
  1329 reloads .ML *and* .thy file, if either one is out of date;
  1330 
  1331 
  1332 *** Classical Reasoner ***
  1333 
  1334 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1335 tactics that use classical reasoning to simplify a subgoal without
  1336 splitting it into several subgoals;
  1337 
  1338 * Safe_tac: like safe_tac but uses the default claset;
  1339 
  1340 
  1341 *** Simplifier ***
  1342 
  1343 * added simplification meta rules:
  1344     (asm_)(full_)simplify: simpset -> thm -> thm;
  1345 
  1346 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1347 logics (again);
  1348 
  1349 * added prems argument to simplification procedures;
  1350 
  1351 * HOL, FOL, ZF: added infix function `addsplits':
  1352   instead of `<simpset> setloop (split_tac <thms>)'
  1353   you can simply write `<simpset> addsplits <thms>'
  1354 
  1355 
  1356 *** Syntax ***
  1357 
  1358 * TYPE('a) syntax for type reflection terms;
  1359 
  1360 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1361 
  1362 * pretty printer: changed order of mixfix annotation preference (again!);
  1363 
  1364 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1365 
  1366 
  1367 *** HOL ***
  1368 
  1369 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1370   with `addloop' of the simplifier to faciliate case splitting in premises.
  1371 
  1372 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1373 
  1374 * HOL/Auth: new protocol proofs including some for the Internet
  1375   protocol TLS;
  1376 
  1377 * HOL/Map: new theory of `maps' a la VDM;
  1378 
  1379 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1380 cancelling out common nat summands from =, <, <= (in)equalities, or
  1381 differences; simplification procedures nat_cancel_factor for
  1382 cancelling common factor from =, <, <= (in)equalities over natural
  1383 sums; nat_cancel contains both kinds of procedures, it is installed by
  1384 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1385 
  1386 * HOL/simplifier: terms of the form
  1387   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1388   are rewritten to
  1389   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1390   and those of the form
  1391   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1392   are rewritten to
  1393   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1394 
  1395 * HOL/datatype
  1396   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1397 
  1398   P(t_case f1 ... fn x) =
  1399      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1400         ...
  1401        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1402      )
  1403 
  1404   and a theorem `split_t_case_asm' of the form
  1405 
  1406   P(t_case f1 ... fn x) =
  1407     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1408         ...
  1409        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1410      )
  1411   which can be added to a simpset via `addsplits'. The existing theorems
  1412   expand_list_case and expand_option_case have been renamed to
  1413   split_list_case and split_option_case.
  1414 
  1415 * HOL/Arithmetic:
  1416   - `pred n' is automatically converted to `n-1'.
  1417     Users are strongly encouraged not to use `pred' any longer,
  1418     because it will disappear altogether at some point.
  1419   - Users are strongly encouraged to write "0 < n" rather than
  1420     "n ~= 0". Theorems and proof tools have been modified towards this
  1421     `standard'.
  1422 
  1423 * HOL/Lists:
  1424   the function "set_of_list" has been renamed "set" (and its theorems too);
  1425   the function "nth" now takes its arguments in the reverse order and
  1426   has acquired the infix notation "!" as in "xs!n".
  1427 
  1428 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1429 
  1430 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1431   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1432 
  1433 * HOL/record: extensible records with schematic structural subtyping
  1434 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1435 still lacks various theorems and concrete record syntax;
  1436 
  1437 
  1438 *** HOLCF ***
  1439 
  1440 * removed "axioms" and "generated by" sections;
  1441 
  1442 * replaced "ops" section by extended "consts" section, which is capable of
  1443   handling the continuous function space "->" directly;
  1444 
  1445 * domain package:
  1446   . proves theorems immediately and stores them in the theory,
  1447   . creates hierachical name space,
  1448   . now uses normal mixfix annotations (instead of cinfix...),
  1449   . minor changes to some names and values (for consistency),
  1450   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1451   . separator between mutual domain defs: changed "," to "and",
  1452   . improved handling of sort constraints;  now they have to
  1453     appear on the left-hand side of the equations only;
  1454 
  1455 * fixed LAM <x,y,zs>.b syntax;
  1456 
  1457 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1458 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1459 
  1460 
  1461 *** FOL and ZF ***
  1462 
  1463 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1464   with `addloop' of the simplifier to faciliate case splitting in premises.
  1465 
  1466 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1467 in HOL, they strip ALL and --> from proved theorems;
  1468 
  1469 
  1470 
  1471 New in Isabelle94-8 (May 1997)
  1472 ------------------------------
  1473 
  1474 *** General Changes ***
  1475 
  1476 * new utilities to build / run / maintain Isabelle etc. (in parts
  1477 still somewhat experimental); old Makefiles etc. still functional;
  1478 
  1479 * new 'Isabelle System Manual';
  1480 
  1481 * INSTALL text, together with ./configure and ./build scripts;
  1482 
  1483 * reimplemented type inference for greater efficiency, better error
  1484 messages and clean internal interface;
  1485 
  1486 * prlim command for dealing with lots of subgoals (an easier way of
  1487 setting goals_limit);
  1488 
  1489 
  1490 *** Syntax ***
  1491 
  1492 * supports alternative (named) syntax tables (parser and pretty
  1493 printer); internal interface is provided by add_modesyntax(_i);
  1494 
  1495 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1496 be used in conjunction with the Isabelle symbol font; uses the
  1497 "symbols" syntax table;
  1498 
  1499 * added token_translation interface (may translate name tokens in
  1500 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1501 the current print_mode); IMPORTANT: user print translation functions
  1502 are responsible for marking newly introduced bounds
  1503 (Syntax.mark_boundT);
  1504 
  1505 * token translations for modes "xterm" and "xterm_color" that display
  1506 names in bold, underline etc. or colors (which requires a color
  1507 version of xterm);
  1508 
  1509 * infixes may now be declared with names independent of their syntax;
  1510 
  1511 * added typed_print_translation (like print_translation, but may
  1512 access type of constant);
  1513 
  1514 
  1515 *** Classical Reasoner ***
  1516 
  1517 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1518 some limitations.  Blast_tac...
  1519   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1520   + ignores elimination rules that don't have the correct format
  1521         (the conclusion MUST be a formula variable)
  1522   + ignores types, which can make HOL proofs fail
  1523   + rules must not require higher-order unification, e.g. apply_type in ZF
  1524     [message "Function Var's argument not a bound variable" relates to this]
  1525   + its proof strategy is more general but can actually be slower
  1526 
  1527 * substitution with equality assumptions no longer permutes other
  1528 assumptions;
  1529 
  1530 * minor changes in semantics of addafter (now called addaltern); renamed
  1531 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1532 (and access functions for it);
  1533 
  1534 * improved combination of classical reasoner and simplifier:
  1535   + functions for handling clasimpsets
  1536   + improvement of addss: now the simplifier is called _after_ the
  1537     safe steps.
  1538   + safe variant of addss called addSss: uses safe simplifications
  1539     _during_ the safe steps. It is more complete as it allows multiple
  1540     instantiations of unknowns (e.g. with slow_tac).
  1541 
  1542 *** Simplifier ***
  1543 
  1544 * added interface for simplification procedures (functions that
  1545 produce *proven* rewrite rules on the fly, depending on current
  1546 redex);
  1547 
  1548 * ordering on terms as parameter (used for ordered rewriting);
  1549 
  1550 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1551 
  1552 * the solver is now split into a safe and an unsafe part.
  1553 This should be invisible for the normal user, except that the
  1554 functions setsolver and addsolver have been renamed to setSolver and
  1555 addSolver; added safe_asm_full_simp_tac;
  1556 
  1557 
  1558 *** HOL ***
  1559 
  1560 * a generic induction tactic `induct_tac' which works for all datatypes and
  1561 also for type `nat';
  1562 
  1563 * a generic case distinction tactic `exhaust_tac' which works for all
  1564 datatypes and also for type `nat';
  1565 
  1566 * each datatype comes with a function `size';
  1567 
  1568 * patterns in case expressions allow tuple patterns as arguments to
  1569 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1570 
  1571 * primrec now also works with type nat;
  1572 
  1573 * recdef: a new declaration form, allows general recursive functions to be
  1574 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1575 
  1576 * the constant for negation has been renamed from "not" to "Not" to
  1577 harmonize with FOL, ZF, LK, etc.;
  1578 
  1579 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1580 infinite lists;
  1581 
  1582 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1583 
  1584 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1585 problems in commutative rings, using axiomatic type classes for + and *;
  1586 
  1587 * more examples in HOL/MiniML and HOL/Auth;
  1588 
  1589 * more default rewrite rules for quantifiers, union/intersection;
  1590 
  1591 * a new constant `arbitrary == @x.False';
  1592 
  1593 * HOLCF/IOA replaces old HOL/IOA;
  1594 
  1595 * HOLCF changes: derived all rules and arities
  1596   + axiomatic type classes instead of classes
  1597   + typedef instead of faking type definitions
  1598   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1599   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1600   + eliminated the types void, one, tr
  1601   + use unit lift and bool lift (with translations) instead of one and tr
  1602   + eliminated blift from Lift3.thy (use Def instead of blift)
  1603   all eliminated rules are derived as theorems --> no visible changes ;
  1604 
  1605 
  1606 *** ZF ***
  1607 
  1608 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1609 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1610 as ZF_cs addSIs [equalityI];
  1611 
  1612 
  1613 
  1614 New in Isabelle94-7 (November 96)
  1615 ---------------------------------
  1616 
  1617 * allowing negative levels (as offsets) in prlev and choplev;
  1618 
  1619 * super-linear speedup for large simplifications;
  1620 
  1621 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1622 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1623 FAIL); can suppress it using the command Delsimps (ex_simps @
  1624 all_simps); De Morgan laws are also now included, by default;
  1625 
  1626 * improved printing of ==>  :  ~:
  1627 
  1628 * new object-logic "Sequents" adds linear logic, while replacing LK
  1629 and Modal (thanks to Sara Kalvala);
  1630 
  1631 * HOL/Auth: correctness proofs for authentication protocols;
  1632 
  1633 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1634 examples on HOL/Auth);
  1635 
  1636 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1637 the rewriter and classical reasoner simultaneously;
  1638 
  1639 * function uresult no longer returns theorems in "standard" format;
  1640 regain previous version by: val uresult = standard o uresult;
  1641 
  1642 
  1643 
  1644 New in Isabelle94-6
  1645 -------------------
  1646 
  1647 * oracles -- these establish an interface between Isabelle and trusted
  1648 external reasoners, which may deliver results as theorems;
  1649 
  1650 * proof objects (in particular record all uses of oracles);
  1651 
  1652 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1653 
  1654 * "constdefs" section in theory files;
  1655 
  1656 * "primrec" section (HOL) no longer requires names;
  1657 
  1658 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1659 
  1660 
  1661 
  1662 New in Isabelle94-5
  1663 -------------------
  1664 
  1665 * reduced space requirements;
  1666 
  1667 * automatic HTML generation from theories;
  1668 
  1669 * theory files no longer require "..." (quotes) around most types;
  1670 
  1671 * new examples, including two proofs of the Church-Rosser theorem;
  1672 
  1673 * non-curried (1994) version of HOL is no longer distributed;
  1674 
  1675 
  1676 
  1677 New in Isabelle94-4
  1678 -------------------
  1679 
  1680 * greatly reduced space requirements;
  1681 
  1682 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1683 
  1684 * searchable theorem database (see the section "Retrieving theorems" on
  1685 page 8 of the Reference Manual);
  1686 
  1687 * new examples, including Grabczewski's monumental case study of the
  1688 Axiom of Choice;
  1689 
  1690 * The previous version of HOL renamed to Old_HOL;
  1691 
  1692 * The new version of HOL (previously called CHOL) uses a curried syntax
  1693 for functions.  Application looks like f a b instead of f(a,b);
  1694 
  1695 * Mutually recursive inductive definitions finally work in HOL;
  1696 
  1697 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1698 translates to the operator "split";
  1699 
  1700 
  1701 
  1702 New in Isabelle94-3
  1703 -------------------
  1704 
  1705 * new infix operator, addss, allowing the classical reasoner to
  1706 perform simplification at each step of its search.  Example:
  1707         fast_tac (cs addss ss)
  1708 
  1709 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1710 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1711 look like (a,b) instead of <a,b>;
  1712 
  1713 * PLEASE NOTE: CHOL will eventually replace HOL!
  1714 
  1715 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1716 It translates to the operator "split".  A new theory of integers is available;
  1717 
  1718 * In ZF, integer numerals now denote two's-complement binary integers.
  1719 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1720 
  1721 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1722 of the Axiom of Choice;
  1723 
  1724 
  1725 
  1726 New in Isabelle94-2
  1727 -------------------
  1728 
  1729 * Significantly faster resolution;
  1730 
  1731 * the different sections in a .thy file can now be mixed and repeated
  1732 freely;
  1733 
  1734 * Database of theorems for FOL, HOL and ZF.  New
  1735 commands including qed, qed_goal and bind_thm store theorems in the database.
  1736 
  1737 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1738 a given theory (thms_of), or find out what theory a theorem was proved in
  1739 (theory_of_thm);
  1740 
  1741 * Bugs fixed in the inductive definition and datatype packages;
  1742 
  1743 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1744 and HOL_dup_cs obsolete;
  1745 
  1746 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1747 have been removed;
  1748 
  1749 * Simpler definition of function space in ZF;
  1750 
  1751 * new results about cardinal and ordinal arithmetic in ZF;
  1752 
  1753 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1754 types;
  1755 
  1756 
  1757 $Id$