NEWS
author wenzelm
Thu Feb 01 20:42:34 2001 +0100 (2001-02-01)
changeset 11016 8f8ba41a5e7a
parent 10998 fece8333adfc
child 11043 2e3bbac8763b
permissions -rw-r--r--
* Pure: 'thms_containing' now takes actual terms as arguments;
* isatool convert assists in eliminating legacy ML scripts;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 *** Overview of INCOMPATIBILITIES ***
     6 
     7 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
     8 gfp_Tarski to gfp_unfold;
     9 
    10 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
    11 
    12 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
    13 relation); infix "^^" has been renamed "``"; infix "``" has been
    14 renamed "`"; "univalent" has been renamed "single_valued";
    15 
    16 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
    17 operation;
    18 
    19 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
    20 
    21 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
    22 
    23 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
    24 consequence, it is no longer monotonic wrt. the local goal context
    25 (which is now passed through the inductive cases);
    26 
    27 * Document preparation: renamed standard symbols \<ll> to \<lless> and
    28 \<gg> to \<ggreater>;
    29 
    30 
    31 *** Document preparation ***
    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 * improved isabelle style files; more abstract symbol implementation
    46 (should now use \isamath{...} and \isatext{...} in custom symbol
    47 definitions);
    48 
    49 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
    50 state; Note that presentation of goal states does not conform to
    51 actual human-readable proof documents.  Please do not include goal
    52 states into document output unless you really know what you are doing!
    53 
    54 * isatool unsymbolize tunes sources for plain ASCII communication;
    55 
    56 
    57 *** Isar ***
    58 
    59 * Pure: Isar now suffers initial goal statements to contain unbound
    60 schematic variables (this does not conform to actual readable proof
    61 documents, due to unpredictable outcome and non-compositional proof
    62 checking); users who know what they are doing may use schematic goals
    63 for Prolog-style synthesis of proven results;
    64 
    65 * Pure: assumption method (an implicit finishing) now handles actual
    66 rules as well;
    67 
    68 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
    69 initial goal, declare "that" only as Pure intro (only for single
    70 steps); the "that" rule assumption may now be involved in implicit
    71 finishing, thus ".." becomes a feasible for trivial obtains;
    72 
    73 * Pure: default proof step now includes 'intro_classes'; thus trivial
    74 instance proofs may be performed by "..";
    75 
    76 * Pure: ?thesis / ?this / "..." now work for pure meta-level
    77 statements as well;
    78 
    79 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
    80 rule (as well as the assumption rule);
    81 
    82 * Pure: 'thm_deps' command visualizes dependencies of theorems and
    83 lemmas, using the graph browser tool;
    84 
    85 * Pure: predict failure of "show" in interactive mode;
    86 
    87 * Pure: 'thms_containing' now takes actual terms as arguments;
    88 
    89 * HOL: improved method 'induct' --- now handles non-atomic goals
    90 (potential INCOMPATIBILITY); tuned error handling;
    91 
    92 * HOL: cases and induct rules now provide explicit hints about the
    93 number of facts to be consumed (0 for "type" and 1 for "set" rules);
    94 any remaining facts are inserted into the goal verbatim;
    95 
    96 * HOL: local contexts (aka cases) may now contain term bindings as
    97 well; the 'cases' and 'induct' methods new provide a ?case binding for
    98 the result to be shown in each case;
    99 
   100 * HOL: added 'recdef_tc' command;
   101 
   102 * isatool convert assists in eliminating legacy ML scripts;
   103 
   104 
   105 *** HOL ***
   106 
   107 * HOL/Library: a collection of generic theories to be used together
   108 with main HOL; the theory loader path already includes this directory
   109 by default; the following existing theories have been moved here:
   110 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   111 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   112 
   113 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   114 modelling and verification task performed in Isabelle/HOL +
   115 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   116 
   117 * HOL basics: added overloaded operations "inverse" and "divide"
   118 (infix "/"), syntax for generic "abs" operation, generic summation
   119 operator;
   120 
   121 * HOL/typedef: simplified package, provide more useful rules (see also
   122 HOL/subset.thy);
   123 
   124 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   125 now expressed as a proper nested rule (old-style tactic scripts may
   126 require atomize_strip_tac to cope with non-atomic premises);
   127 
   128 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   129 to "split_conv" (old name still available for compatibility);
   130 
   131 * HOL: improved concrete syntax for strings (e.g. allows translation
   132 rules with string literals);
   133 
   134 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   135 and Fleuriot's mechanization of analysis;
   136 
   137 * HOL-Real, HOL-Hyperreals: improved arithmetic simplification;
   138 
   139 
   140 *** CTT ***
   141 
   142 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   143 "lam" is displayed as TWO lambda-symbols
   144 
   145 * CTT: theory Main now available, containing everything (that is, Bool
   146 and Arith);
   147 
   148 
   149 *** General ***
   150 
   151 * print modes "brackets" and "no_brackets" control output of nested =>
   152 (types) and ==> (props); the default behaviour is "brackets";
   153 
   154 * system: support Poly/ML 4.0 (current beta versions);
   155 
   156 * Pure: the Simplifier has been implemented properly as a derived rule
   157 outside of the actual kernel (at last!); the overall performance
   158 penalty in practical applications is about 50%, while reliability of
   159 the Isabelle inference kernel has been greatly improved;
   160 
   161 * Provers: fast_tac (and friends) now handle actual object-logic rules
   162 as assumptions as well;
   163 
   164 
   165 
   166 New in Isabelle99-1 (October 2000)
   167 ----------------------------------
   168 
   169 *** Overview of INCOMPATIBILITIES ***
   170 
   171 * HOL: simplification of natural numbers is much changed; to partly
   172 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   173 issue the following ML commands:
   174 
   175   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   176   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   177 
   178 * HOL: simplification no longer dives into case-expressions; this is
   179 controlled by "t.weak_case_cong" for each datatype t;
   180 
   181 * HOL: nat_less_induct renamed to less_induct;
   182 
   183 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   184 fixsome to patch .thy and .ML sources automatically;
   185 
   186   select_equality  -> some_equality
   187   select_eq_Ex     -> some_eq_ex
   188   selectI2EX       -> someI2_ex
   189   selectI2         -> someI2
   190   selectI          -> someI
   191   select1_equality -> some1_equality
   192   Eps_sym_eq       -> some_sym_eq_trivial
   193   Eps_eq           -> some_eq_trivial
   194 
   195 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   196 
   197 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   198 instead);
   199 
   200 * HOL: the recursion equations generated by 'recdef' are now called
   201 f.simps instead of f.rules;
   202 
   203 * HOL: qed_spec_mp now also handles bounded ALL as well;
   204 
   205 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   206 sometimes be needed;
   207 
   208 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   209 
   210 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   211 
   212 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   213 product is now "<*>" instead of "Times"; the lexicographic product is
   214 now "<*lex*>" instead of "**";
   215 
   216 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   217 of main HOL, but was unused); better use HOL's datatype package;
   218 
   219 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   220 the old syntax may be recovered as follows:
   221 
   222   syntax (symbols)
   223     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   224       (infixl "\\<oplus>" 100)
   225 
   226 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   227 
   228 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   229 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   230 internally;
   231 
   232 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   233 changed from A/r to A//r;
   234 
   235 * ZF: new treatment of arithmetic (nat & int) may break some old
   236 proofs;
   237 
   238 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   239 rulify -> rule_format, elimify -> elim_format, ...);
   240 
   241 * Isar/Provers: intro/elim/dest attributes changed; renamed
   242 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   243 should have to change intro!! to intro? only); replaced "delrule" by
   244 "rule del";
   245 
   246 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   247 
   248 * Provers: strengthened force_tac by using new first_best_tac;
   249 
   250 * LaTeX document preparation: several changes of isabelle.sty (see
   251 lib/texinputs);
   252 
   253 
   254 *** Document preparation ***
   255 
   256 * formal comments (text blocks etc.) in new-style theories may now
   257 contain antiquotations of thm/prop/term/typ/text to be presented
   258 according to latex print mode; concrete syntax is like this:
   259 @{term[show_types] "f(x) = a + x"};
   260 
   261 * isatool mkdir provides easy setup of Isabelle session directories,
   262 including proper document sources;
   263 
   264 * generated LaTeX sources are now deleted after successful run
   265 (isatool document -c); may retain a copy somewhere else via -D option
   266 of isatool usedir;
   267 
   268 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   269 style files, achieving self-contained LaTeX sources and simplifying
   270 LaTeX debugging;
   271 
   272 * old-style theories now produce (crude) LaTeX output as well;
   273 
   274 * browser info session directories are now self-contained (may be put
   275 on WWW server seperately); improved graphs of nested sessions; removed
   276 graph for 'all sessions';
   277 
   278 * several improvements in isabelle style files; \isabellestyle{it}
   279 produces fake math mode output; \isamarkupheader is now \section by
   280 default; see lib/texinputs/isabelle.sty etc.;
   281 
   282 
   283 *** Isar ***
   284 
   285 * Isar/Pure: local results and corresponding term bindings are now
   286 subject to Hindley-Milner polymorphism (similar to ML); this
   287 accommodates incremental type-inference very nicely;
   288 
   289 * Isar/Pure: new derived language element 'obtain' supports
   290 generalized existence reasoning;
   291 
   292 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   293 support accumulation of results, without applying any rules yet;
   294 useful to collect intermediate results without explicit name
   295 references, and for use with transitivity rules with more than 2
   296 premises;
   297 
   298 * Isar/Pure: scalable support for case-analysis type proofs: new
   299 'case' language element refers to local contexts symbolically, as
   300 produced by certain proof methods; internally, case names are attached
   301 to theorems as "tags";
   302 
   303 * Isar/Pure: theory command 'hide' removes declarations from
   304 class/type/const name spaces;
   305 
   306 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   307 indicate potential overloading;
   308 
   309 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   310 
   311 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   312 "{a,b,c}" instead of {a,b,c};
   313 
   314 * Isar/Pure now provides its own version of intro/elim/dest
   315 attributes; useful for building new logics, but beware of confusion
   316 with the version in Provers/classical;
   317 
   318 * Isar/Pure: the local context of (non-atomic) goals is provided via
   319 case name 'antecedent';
   320 
   321 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   322 to the current context is now done automatically);
   323 
   324 * Isar/Pure: theory command 'method_setup' provides a simple interface
   325 for definining proof methods in ML;
   326 
   327 * Isar/Provers: intro/elim/dest attributes changed; renamed
   328 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   329 most cases, one should have to change intro!! to intro? only);
   330 replaced "delrule" by "rule del";
   331 
   332 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   333 'symmetric' attribute (the latter supercedes [RS sym]);
   334 
   335 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   336 method modifier); 'simp' method: 'only:' modifier removes loopers as
   337 well (including splits);
   338 
   339 * Isar/Provers: Simplifier and Classical methods now support all kind
   340 of modifiers used in the past, including 'cong', 'iff', etc.
   341 
   342 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   343 of Simplifier and Classical reasoner);
   344 
   345 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   346 now support named cases; major packages (inductive, datatype, primrec,
   347 recdef) support case names and properly name parameters;
   348 
   349 * Isar/HOL: new transitivity rules for substitution in inequalities --
   350 monotonicity conditions are extracted to be proven at end of
   351 calculations;
   352 
   353 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   354 method anyway;
   355 
   356 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   357 split_if split_if_asm; datatype package provides theorems foo.splits =
   358 foo.split foo.split_asm for each datatype;
   359 
   360 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   361 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   362 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   363 use "(cases (simplified))" method in proper proof texts);
   364 
   365 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   366 
   367 * Isar: names of theorems etc. may be natural numbers as well;
   368 
   369 * Isar: 'pr' command: optional arguments for goals_limit and
   370 ProofContext.prems_limit; no longer prints theory contexts, but only
   371 proof states;
   372 
   373 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   374 additional print modes to be specified; e.g. "pr(latex)" will print
   375 proof state according to the Isabelle LaTeX style;
   376 
   377 * Isar: improved support for emulating tactic scripts, including proof
   378 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   379 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   380 (for HOL datatypes);
   381 
   382 * Isar: simplified (more robust) goal selection of proof methods: 1st
   383 goal, all goals, or explicit goal specifier (tactic emulation); thus
   384 'proof method scripts' have to be in depth-first order;
   385 
   386 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   387 
   388 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   389 should instead use individual commands for printing items
   390 (print_commands, print_methods etc.);
   391 
   392 * Isar: added 'nothing' --- the empty list of theorems;
   393 
   394 
   395 *** HOL ***
   396 
   397 * HOL/MicroJava: formalization of a fragment of Java, together with a
   398 corresponding virtual machine and a specification of its bytecode
   399 verifier and a lightweight bytecode verifier, including proofs of
   400 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   401 Cornelia Pusch (see also the homepage of project Bali at
   402 http://isabelle.in.tum.de/Bali/);
   403 
   404 * HOL/Algebra: new theory of rings and univariate polynomials, by
   405 Clemens Ballarin;
   406 
   407 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   408 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   409 Rasmussen;
   410 
   411 * HOL/Lattice: fundamental concepts of lattice theory and order
   412 structures, including duals, properties of bounds versus algebraic
   413 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   414 Theorem for complete lattices etc.; may also serve as a demonstration
   415 for abstract algebraic reasoning using axiomatic type classes, and
   416 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   417 
   418 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   419 von Oheimb;
   420 
   421 * HOL/IMPP: extension of IMP with local variables and mutually
   422 recursive procedures, by David von Oheimb;
   423 
   424 * HOL/Lambda: converted into new-style theory and document;
   425 
   426 * HOL/ex/Multiquote: example of multiple nested quotations and
   427 anti-quotations -- basically a generalized version of de-Bruijn
   428 representation; very useful in avoiding lifting of operations;
   429 
   430 * HOL/record: added general record equality rule to simpset; fixed
   431 select-update simplification procedure to handle extended records as
   432 well; admit "r" as field name;
   433 
   434 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   435 other numeric types and also as the identity of groups, rings, etc.;
   436 
   437 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   438 Types nat and int belong to this axclass;
   439 
   440 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   441    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   442    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   443   two terms #m*u and #n*u are replaced by #(m+n)*u
   444     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   445   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   446     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   447 
   448 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   449 powerful prover for predicate logic but knows nothing of clasets; see
   450 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   451 
   452 * HOL: new version of "case_tac" subsumes both boolean case split and
   453 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   454 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   455 
   456 * HOL: simplification no longer dives into case-expressions: only the
   457 selector expression is simplified, but not the remaining arms; to
   458 enable full simplification of case-expressions for datatype t, you may
   459 remove t.weak_case_cong from the simpset, either globally (Delcongs
   460 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   461 
   462 * HOL/recdef: the recursion equations generated by 'recdef' for
   463 function 'f' are now called f.simps instead of f.rules; if all
   464 termination conditions are proved automatically, these simplification
   465 rules are added to the simpset, as in primrec; rules may be named
   466 individually as well, resulting in a separate list of theorems for
   467 each equation;
   468 
   469 * HOL/While is a new theory that provides a while-combinator. It
   470 permits the definition of tail-recursive functions without the
   471 provision of a termination measure. The latter is necessary once the
   472 invariant proof rule for while is applied.
   473 
   474 * HOL: new (overloaded) notation for the set of elements below/above
   475 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   476 
   477 * HOL: theorems impI, allI, ballI bound as "strip";
   478 
   479 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   480 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   481 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   482 
   483 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   484 
   485 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   486 main HOL, but was unused);
   487 
   488 * HOL: fewer consts declared as global (e.g. have to refer to
   489 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   490 
   491 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   492 in case of overlap with user translations (e.g. judgements over
   493 tuples); (note that the underlying logical represenation is still
   494 bogus);
   495 
   496 
   497 *** ZF ***
   498 
   499 * ZF: simplification automatically cancels common terms in arithmetic
   500 expressions over nat and int;
   501 
   502 * ZF: new treatment of nat to minimize type-checking: all operators
   503 coerce their operands to a natural number using the function natify,
   504 making the algebraic laws unconditional;
   505 
   506 * ZF: as above, for int: operators coerce their operands to an integer
   507 using the function intify;
   508 
   509 * ZF: the integer library now contains many of the usual laws for the
   510 orderings, including $<=, and monotonicity laws for $+ and $*;
   511 
   512 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   513 simplification;
   514 
   515 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   516 to the simplifier and classical reasoner simultaneously;
   517 
   518 
   519 *** General ***
   520 
   521 * Provers: blast_tac now handles actual object-logic rules as
   522 assumptions; note that auto_tac uses blast_tac internally as well;
   523 
   524 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   525 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   526 
   527 * Provers: delrules now handles destruct rules as well (no longer need
   528 explicit make_elim);
   529 
   530 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   531   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   532 use instead the strong form,
   533   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   534 in HOL, FOL and ZF the function cla_make_elim will create such rules
   535 from destruct-rules;
   536 
   537 * Provers: Simplifier.easy_setup provides a fast path to basic
   538 Simplifier setup for new object-logics;
   539 
   540 * Pure: AST translation rules no longer require constant head on LHS;
   541 
   542 * Pure: improved name spaces: ambiguous output is qualified; support
   543 for hiding of names;
   544 
   545 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   546 XSYMBOL_HOME; no longer need to do manual configuration in most
   547 situations;
   548 
   549 * system: compression of ML heaps images may now be controlled via -c
   550 option of isabelle and isatool usedir (currently only observed by
   551 Poly/ML);
   552 
   553 * system: isatool installfonts may handle X-Symbol fonts as well (very
   554 useful for remote X11);
   555 
   556 * system: provide TAGS file for Isabelle sources;
   557 
   558 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   559 order;
   560 
   561 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   562 timing flag supersedes proof_timing and Toplevel.trace;
   563 
   564 * ML: new combinators |>> and |>>> for incremental transformations
   565 with secondary results (e.g. certain theory extensions):
   566 
   567 * ML: PureThy.add_defs gets additional argument to indicate potential
   568 overloading (usually false);
   569 
   570 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   571 results;
   572 
   573 
   574 
   575 New in Isabelle99 (October 1999)
   576 --------------------------------
   577 
   578 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   579 
   580 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   581 are no longer simplified.  (This allows the simplifier to unfold recursive
   582 functional programs.)  To restore the old behaviour, declare
   583 
   584     Delcongs [if_weak_cong];
   585 
   586 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   587 complement;
   588 
   589 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   590 
   591 * HOL/datatype: mutual_induct_tac no longer exists --
   592   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   593 
   594 * HOL/typedef: fixed type inference for representing set; type
   595 arguments now have to occur explicitly on the rhs as type constraints;
   596 
   597 * ZF: The con_defs part of an inductive definition may no longer refer
   598 to constants declared in the same theory;
   599 
   600 * HOL, ZF: the function mk_cases, generated by the inductive
   601 definition package, has lost an argument.  To simplify its result, it
   602 uses the default simpset instead of a supplied list of theorems.
   603 
   604 * HOL/List: the constructors of type list are now Nil and Cons;
   605 
   606 * Simplifier: the type of the infix ML functions
   607         setSSolver addSSolver setSolver addSolver
   608 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   609 for packaging solvers. A solver is created via
   610         mk_solver: string -> (thm list -> int -> tactic) -> solver
   611 where the string argument is only a comment.
   612 
   613 
   614 *** Proof tools ***
   615 
   616 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   617 decision procedure for linear arithmetic. Currently it is used for
   618 types `nat', `int', and `real' in HOL (see below); it can, should and
   619 will be instantiated for other types and logics as well.
   620 
   621 * The simplifier now accepts rewrite rules with flexible heads, eg
   622      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   623   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   624   matching.
   625 
   626 
   627 *** General ***
   628 
   629 * New Isabelle/Isar subsystem provides an alternative to traditional
   630 tactical theorem proving; together with the ProofGeneral/isar user
   631 interface it offers an interactive environment for developing human
   632 readable proof documents (Isar == Intelligible semi-automated
   633 reasoning); for further information see isatool doc isar-ref,
   634 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   635 
   636 * improved and simplified presentation of theories: better HTML markup
   637 (including colors), graph views in several sizes; isatool usedir now
   638 provides a proper interface for user theories (via -P option); actual
   639 document preparation based on (PDF)LaTeX is available as well (for
   640 new-style theories only); see isatool doc system for more information;
   641 
   642 * native support for Proof General, both for classic Isabelle and
   643 Isabelle/Isar;
   644 
   645 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   646 using the graph browser tool;
   647 
   648 * Isabelle manuals now also available as PDF;
   649 
   650 * theory loader rewritten from scratch (may not be fully
   651 bug-compatible); old loadpath variable has been replaced by show_path,
   652 add_path, del_path, reset_path functions; new operations such as
   653 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   654 isatool doc ref);
   655 
   656 * improved isatool install: option -k creates KDE application icon,
   657 option -p DIR installs standalone binaries;
   658 
   659 * added ML_PLATFORM setting (useful for cross-platform installations);
   660 more robust handling of platform specific ML images for SML/NJ;
   661 
   662 * the settings environment is now statically scoped, i.e. it is never
   663 created again in sub-processes invoked from isabelle, isatool, or
   664 Isabelle;
   665 
   666 * path element specification '~~' refers to '$ISABELLE_HOME';
   667 
   668 * in locales, the "assumes" and "defines" parts may be omitted if
   669 empty;
   670 
   671 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   672 long arrows);
   673 
   674 * new print_mode "HTML";
   675 
   676 * new flag show_tags controls display of tags of theorems (which are
   677 basically just comments that may be attached by some tools);
   678 
   679 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   680 mode and goal output format:
   681 
   682 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   683 244c244
   684 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   685 ---
   686 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   687 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   688 181c181
   689 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   690 ---
   691 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   692 
   693 * function bind_thms stores lists of theorems (cf. bind_thm);
   694 
   695 * new shorthand tactics ftac, eatac, datac, fatac;
   696 
   697 * qed (and friends) now accept "" as result name; in that case the
   698 theorem is not stored, but proper checks and presentation of the
   699 result still apply;
   700 
   701 * theorem database now also indexes constants "Trueprop", "all",
   702 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   703 
   704 
   705 *** HOL ***
   706 
   707 ** HOL arithmetic **
   708 
   709 * There are now decision procedures for linear arithmetic over nat and
   710 int:
   711 
   712 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   713 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   714 are treated as atomic; subformulae not involving type `nat' or `int'
   715 are ignored; quantified subformulae are ignored unless they are
   716 positive universal or negative existential. The tactic has to be
   717 invoked by hand and can be a little bit slow. In particular, the
   718 running time is exponential in the number of occurrences of `min' and
   719 `max', and `-' on `nat'.
   720 
   721 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   722 (negated) (in)equalities among the premises and the conclusion into
   723 account (i.e. no compound formulae) and does not know about `min' and
   724 `max', and `-' on `nat'. It is fast and is used automatically by the
   725 simplifier.
   726 
   727 NB: At the moment, these decision procedures do not cope with mixed
   728 nat/int formulae where the two parts interact, such as `m < n ==>
   729 int(m) < int(n)'.
   730 
   731 * HOL/Numeral provides a generic theory of numerals (encoded
   732 efficiently as bit strings); setup for types nat/int/real is in place;
   733 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   734 int, existing theories and proof scripts may require a few additional
   735 type constraints;
   736 
   737 * integer division and remainder can now be performed on constant
   738 arguments;
   739 
   740 * many properties of integer multiplication, division and remainder
   741 are now available;
   742 
   743 * An interface to the Stanford Validity Checker (SVC) is available through the
   744 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   745 are proved automatically.  SVC must be installed separately, and its results
   746 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   747 invocation of the underlying oracle).  For SVC see
   748   http://verify.stanford.edu/SVC
   749 
   750 * IsaMakefile: the HOL-Real target now builds an actual image;
   751 
   752 
   753 ** HOL misc **
   754 
   755 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   756 (in Isabelle/Isar) -- by Gertrud Bauer;
   757 
   758 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   759 analysis for assembly languages with subtypes;
   760 
   761 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   762 -- avoids syntactic ambiguities and treats state, transition, and
   763 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   764 changed syntax and (many) tactics;
   765 
   766 * HOL/inductive: Now also handles more general introduction rules such
   767   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   768   theorems are now maintained within the theory (maintained via the
   769   "mono" attribute);
   770 
   771 * HOL/datatype: Now also handles arbitrarily branching datatypes
   772   (using function types) such as
   773 
   774   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   775 
   776 * HOL/record: record_simproc (part of the default simpset) takes care
   777 of selectors applied to updated records; record_split_tac is no longer
   778 part of the default claset; update_defs may now be removed from the
   779 simpset in many cases; COMPATIBILITY: old behavior achieved by
   780 
   781   claset_ref () := claset() addSWrapper record_split_wrapper;
   782   Delsimprocs [record_simproc]
   783 
   784 * HOL/typedef: fixed type inference for representing set; type
   785 arguments now have to occur explicitly on the rhs as type constraints;
   786 
   787 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   788 names rather than an ML expression;
   789 
   790 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   791 supplied later.  Program schemes can be defined, such as
   792     "While B C s = (if B s then While B C (C s) else s)"
   793 where the well-founded relation can be chosen after B and C have been given.
   794 
   795 * HOL/List: the constructors of type list are now Nil and Cons;
   796 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   797 course, ML tools referring to List.list.op # etc. have to be adapted;
   798 
   799 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   800 disabled by default; run isabelle with option -m HOL to get back to
   801 the original Gordon/HOL-style output;
   802 
   803 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   804 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   805 
   806 * HOL basic syntax simplified (more orthogonal): all variants of
   807 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   808 Eps operator is provided as well: "SOME x. P[x]";
   809 
   810 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   811 
   812 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   813 thus available for user theories;
   814 
   815 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   816 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   817 time;
   818 
   819 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   820 several times and then mp;
   821 
   822 
   823 *** LK ***
   824 
   825 * the notation <<...>> is now available as a notation for sequences of
   826 formulas;
   827 
   828 * the simplifier is now installed
   829 
   830 * the axiom system has been generalized (thanks to Soren Heilmann)
   831 
   832 * the classical reasoner now has a default rule database
   833 
   834 
   835 *** ZF ***
   836 
   837 * new primrec section allows primitive recursive functions to be given
   838 directly (as in HOL) over datatypes and the natural numbers;
   839 
   840 * new tactics induct_tac and exhaust_tac for induction (or case
   841 analysis) over datatypes and the natural numbers;
   842 
   843 * the datatype declaration of type T now defines the recursor T_rec;
   844 
   845 * simplification automatically does freeness reasoning for datatype
   846 constructors;
   847 
   848 * automatic type-inference, with AddTCs command to insert new
   849 type-checking rules;
   850 
   851 * datatype introduction rules are now added as Safe Introduction rules
   852 to the claset;
   853 
   854 * the syntax "if P then x else y" is now available in addition to
   855 if(P,x,y);
   856 
   857 
   858 *** Internal programming interfaces ***
   859 
   860 * tuned simplifier trace output; new flag debug_simp;
   861 
   862 * structures Vartab / Termtab (instances of TableFun) offer efficient
   863 tables indexed by indexname_ord / term_ord (compatible with aconv);
   864 
   865 * AxClass.axclass_tac lost the theory argument;
   866 
   867 * tuned current_goals_markers semantics: begin / end goal avoids
   868 printing empty lines;
   869 
   870 * removed prs and prs_fn hook, which was broken because it did not
   871 include \n in its semantics, forcing writeln to add one
   872 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   873 string -> unit if you really want to output text without newline;
   874 
   875 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   876 plain output, interface builders may have to enable 'isabelle_font'
   877 mode to get Isabelle font glyphs as before;
   878 
   879 * refined token_translation interface; INCOMPATIBILITY: output length
   880 now of type real instead of int;
   881 
   882 * theory loader actions may be traced via new ThyInfo.add_hook
   883 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   884 your own database of information attached to *whole* theories -- as
   885 opposed to intra-theory data slots offered via TheoryDataFun;
   886 
   887 * proper handling of dangling sort hypotheses (at last!);
   888 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   889 extra sort hypotheses that can be witnessed from the type signature;
   890 the force_strip_shyps flag is gone, any remaining shyps are simply
   891 left in the theorem (with a warning issued by strip_shyps_warning);
   892 
   893 
   894 
   895 New in Isabelle98-1 (October 1998)
   896 ----------------------------------
   897 
   898 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   899 
   900 * several changes of automated proof tools;
   901 
   902 * HOL: major changes to the inductive and datatype packages, including
   903 some minor incompatibilities of theory syntax;
   904 
   905 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   906 called `inj_on';
   907 
   908 * HOL: removed duplicate thms in Arith:
   909   less_imp_add_less  should be replaced by  trans_less_add1
   910   le_imp_add_le      should be replaced by  trans_le_add1
   911 
   912 * HOL: unary minus is now overloaded (new type constraints may be
   913 required);
   914 
   915 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   916 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   917 now taken as an integer constant.
   918 
   919 * Pure: ML function 'theory_of' renamed to 'theory';
   920 
   921 
   922 *** Proof tools ***
   923 
   924 * Simplifier:
   925   1. Asm_full_simp_tac is now more aggressive.
   926      1. It will sometimes reorient premises if that increases their power to
   927         simplify.
   928      2. It does no longer proceed strictly from left to right but may also
   929         rotate premises to achieve further simplification.
   930      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   931      old Asm_full_simp_tac in that it does not rotate premises.
   932   2. The simplifier now knows a little bit about nat-arithmetic.
   933 
   934 * Classical reasoner: wrapper mechanism for the classical reasoner now
   935 allows for selected deletion of wrappers, by introduction of names for
   936 wrapper functionals.  This implies that addbefore, addSbefore,
   937 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   938 and that adding two tactics with the same name overwrites the first
   939 one (emitting a warning).
   940   type wrapper = (int -> tactic) -> (int -> tactic)
   941   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   942   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   943   delWrapper, delSWrapper: claset *  string            -> claset
   944   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   945 
   946 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   947 semantics; addbefore now affects only the unsafe part of step_tac
   948 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   949 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   950 by Force_tac;
   951 
   952 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   953 compWrapper; added safe wrapper (and access functions for it);
   954 
   955 * HOL/split_all_tac is now much faster and fails if there is nothing
   956 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   957 and the names of the automatically generated variables have changed.
   958 split_all_tac has moved within claset() from unsafe wrappers to safe
   959 wrappers, which means that !!-bound variables are split much more
   960 aggressively, and safe_tac and clarify_tac now split such variables.
   961 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   962 Note: the same holds for record_split_tac, which does the job of
   963 split_all_tac for record fields.
   964 
   965 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   966 permanently to the default simpset using Addsplits just like
   967 Addsimps. They can be removed via Delsplits just like
   968 Delsimps. Lower-case versions are also available.
   969 
   970 * HOL/Simplifier: The rule split_if is now part of the default
   971 simpset. This means that the simplifier will eliminate all occurrences
   972 of if-then-else in the conclusion of a goal. To prevent this, you can
   973 either remove split_if completely from the default simpset by
   974 `Delsplits [split_if]' or remove it in a specific call of the
   975 simplifier using `... delsplits [split_if]'.  You can also add/delete
   976 other case splitting rules to/from the default simpset: every datatype
   977 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   978 t is the name of the datatype).
   979 
   980 * Classical reasoner / Simplifier combination: new force_tac (and
   981 derivatives Force_tac, force) combines rewriting and classical
   982 reasoning (and whatever other tools) similarly to auto_tac, but is
   983 aimed to solve the given subgoal completely.
   984 
   985 
   986 *** General ***
   987 
   988 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   989 and `goalw': the theory is no longer needed as an explicit argument -
   990 the current theory context is used; assumptions are no longer returned
   991 at the ML-level unless one of them starts with ==> or !!; it is
   992 recommended to convert to these new commands using isatool fixgoal
   993 (backup your sources first!);
   994 
   995 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   996 the current theory context, and 'theory' to lookup stored theories;
   997 
   998 * new theory section 'locale' for declaring constants, assumptions and
   999 definitions that have local scope;
  1000 
  1001 * new theory section 'nonterminals' for purely syntactic types;
  1002 
  1003 * new theory section 'setup' for generic ML setup functions
  1004 (e.g. package initialization);
  1005 
  1006 * the distribution now includes Isabelle icons: see
  1007 lib/logo/isabelle-{small,tiny}.xpm;
  1008 
  1009 * isatool install - install binaries with absolute references to
  1010 ISABELLE_HOME/bin;
  1011 
  1012 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1013 
  1014 * print mode 'emacs' reserved for Isamode;
  1015 
  1016 * support multiple print (ast) translations per constant name;
  1017 
  1018 * theorems involving oracles are now printed with a suffixed [!];
  1019 
  1020 
  1021 *** HOL ***
  1022 
  1023 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1024 
  1025 * HOL/inductive package reorganized and improved: now supports mutual
  1026 definitions such as
  1027 
  1028   inductive EVEN ODD
  1029     intrs
  1030       null "0 : EVEN"
  1031       oddI "n : EVEN ==> Suc n : ODD"
  1032       evenI "n : ODD ==> Suc n : EVEN"
  1033 
  1034 new theorem list "elims" contains an elimination rule for each of the
  1035 recursive sets; inductive definitions now handle disjunctive premises
  1036 correctly (also ZF);
  1037 
  1038 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1039 "mutual_induct" no longer exists - the induction rule is always
  1040 contained in "induct";
  1041 
  1042 
  1043 * HOL/datatype package re-implemented and greatly improved: now
  1044 supports mutually recursive datatypes such as
  1045 
  1046   datatype
  1047     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1048             | SUM ('a aexp) ('a aexp)
  1049             | DIFF ('a aexp) ('a aexp)
  1050             | NUM 'a
  1051   and
  1052     'a bexp = LESS ('a aexp) ('a aexp)
  1053             | AND ('a bexp) ('a bexp)
  1054             | OR ('a bexp) ('a bexp)
  1055 
  1056 as well as indirectly recursive datatypes such as
  1057 
  1058   datatype
  1059     ('a, 'b) term = Var 'a
  1060                   | App 'b ((('a, 'b) term) list)
  1061 
  1062 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1063 induction on mutually / indirectly recursive datatypes.
  1064 
  1065 Primrec equations are now stored in theory and can be accessed via
  1066 <function_name>.simps.
  1067 
  1068 INCOMPATIBILITIES:
  1069 
  1070   - Theories using datatypes must now have theory Datatype as an
  1071     ancestor.
  1072   - The specific <typename>.induct_tac no longer exists - use the
  1073     generic induct_tac instead.
  1074   - natE has been renamed to nat.exhaust - use exhaust_tac
  1075     instead of res_inst_tac ... natE. Note that the variable
  1076     names in nat.exhaust differ from the names in natE, this
  1077     may cause some "fragile" proofs to fail.
  1078   - The theorems split_<typename>_case and split_<typename>_case_asm
  1079     have been renamed to <typename>.split and <typename>.split_asm.
  1080   - Since default sorts of type variables are now handled correctly,
  1081     some datatype definitions may have to be annotated with explicit
  1082     sort constraints.
  1083   - Primrec definitions no longer require function name and type
  1084     of recursive argument.
  1085 
  1086 Consider using isatool fixdatatype to adapt your theories and proof
  1087 scripts to the new package (backup your sources first!).
  1088 
  1089 
  1090 * HOL/record package: considerably improved implementation; now
  1091 includes concrete syntax for record types, terms, updates; theorems
  1092 for surjective pairing and splitting !!-bound record variables; proof
  1093 support is as follows:
  1094 
  1095   1) standard conversions (selectors or updates applied to record
  1096 constructor terms) are part of the standard simpset;
  1097 
  1098   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1099 made part of standard simpset and claset via addIffs;
  1100 
  1101   3) a tactic for record field splitting (record_split_tac) is part of
  1102 the standard claset (addSWrapper);
  1103 
  1104 To get a better idea about these rules you may retrieve them via
  1105 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1106 the name of your record type.
  1107 
  1108 The split tactic 3) conceptually simplifies by the following rule:
  1109 
  1110   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1111 
  1112 Thus any record variable that is bound by meta-all will automatically
  1113 blow up into some record constructor term, consequently the
  1114 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1115 solve record problems automatically.
  1116 
  1117 
  1118 * reorganized the main HOL image: HOL/Integ and String loaded by
  1119 default; theory Main includes everything;
  1120 
  1121 * automatic simplification of integer sums and comparisons, using cancellation;
  1122 
  1123 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1124 
  1125 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1126 
  1127 * many new identities for unions, intersections, set difference, etc.;
  1128 
  1129 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1130 called split_if, split_split, split_sum_case and split_nat_case (to go
  1131 with add/delsplits);
  1132 
  1133 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1134 (?x::unit) = (); this is made part of the default simpset, which COULD
  1135 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1136 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1137 unit_abs_eta_conv is added in order to counter the effect of
  1138 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1139 %u.f();
  1140 
  1141 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1142 makes more sense);
  1143 
  1144 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1145   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1146   disjointness reasoning but breaking a few old proofs.
  1147 
  1148 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1149 to 'converse' from 'inverse' (for compatibility with ZF and some
  1150 literature);
  1151 
  1152 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1153 the well-founded relation;
  1154 
  1155 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1156     Compl A.  The "Compl" syntax remains available as input syntax for this
  1157     release ONLY.
  1158 
  1159 * HOL/Update: new theory of function updates:
  1160     f(a:=b) == %x. if x=a then b else f x
  1161 may also be iterated as in f(a:=b,c:=d,...);
  1162 
  1163 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1164 
  1165 * HOL/List:
  1166   - new function list_update written xs[i:=v] that updates the i-th
  1167     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1168   - new function `upt' written [i..j(] which generates the list
  1169     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1170     bound write [i..j], which is a shorthand for [i..j+1(].
  1171   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1172 
  1173 * HOL/Arith:
  1174   - removed 'pred' (predecessor) function;
  1175   - generalized some theorems about n-1;
  1176   - many new laws about "div" and "mod";
  1177   - new laws about greatest common divisors (see theory ex/Primes);
  1178 
  1179 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1180 instead of "inverse";
  1181 
  1182 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1183   of the multiset ordering;
  1184 
  1185 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1186   (not included by default);
  1187 
  1188 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1189 
  1190 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1191   programs, i.e. different program variables may have different types.
  1192 
  1193 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1194   [previously, this check worked only if the rewrite rule was unconditional]
  1195   Now rew can involve either definitions or equalities (either == or =).
  1196 
  1197 
  1198 *** ZF ***
  1199 
  1200 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1201   only the theorems proved on ZF.ML;
  1202 
  1203 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1204   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1205   disjointness reasoning but breaking a few old proofs.
  1206 
  1207 * ZF/Update: new theory of function updates
  1208     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1209   may also be iterated as in f(a:=b,c:=d,...);
  1210 
  1211 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1212 
  1213 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1214   [previously, this check worked only if the rewrite rule was unconditional]
  1215   Now rew can involve either definitions or equalities (either == or =).
  1216 
  1217 * case_tac provided for compatibility with HOL
  1218     (like the old excluded_middle_tac, but with subgoals swapped)
  1219 
  1220 
  1221 *** Internal programming interfaces ***
  1222 
  1223 * Pure: several new basic modules made available for general use, see
  1224 also src/Pure/README;
  1225 
  1226 * improved the theory data mechanism to support encapsulation (data
  1227 kind name replaced by private Object.kind, acting as authorization
  1228 key); new type-safe user interface via functor TheoryDataFun; generic
  1229 print_data function becomes basically useless;
  1230 
  1231 * removed global_names compatibility flag -- all theory declarations
  1232 are qualified by default;
  1233 
  1234 * module Pure/Syntax now offers quote / antiquote translation
  1235 functions (useful for Hoare logic etc. with implicit dependencies);
  1236 see HOL/ex/Antiquote for an example use;
  1237 
  1238 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1239 cterm -> thm;
  1240 
  1241 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1242 subgoal;
  1243 
  1244 * Display.print_goals function moved to Locale.print_goals;
  1245 
  1246 * standard print function for goals supports current_goals_markers
  1247 variable for marking begin of proof, end of proof, start of goal; the
  1248 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1249 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1250 for example;
  1251 
  1252 
  1253 
  1254 New in Isabelle98 (January 1998)
  1255 --------------------------------
  1256 
  1257 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1258 
  1259 * changed lexical syntax of terms / types: dots made part of long
  1260 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1261 
  1262 * simpset (and claset) reference variable replaced by functions
  1263 simpset / simpset_ref;
  1264 
  1265 * no longer supports theory aliases (via merge) and non-trivial
  1266 implicit merge of thms' signatures;
  1267 
  1268 * most internal names of constants changed due to qualified names;
  1269 
  1270 * changed Pure/Sequence interface (see Pure/seq.ML);
  1271 
  1272 
  1273 *** General Changes ***
  1274 
  1275 * hierachically structured name spaces (for consts, types, axms, thms
  1276 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1277 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1278 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1279 long_names for fully qualified output names; NOTE: ML programs
  1280 (special tactics, packages etc.) referring to internal names may have
  1281 to be adapted to cope with fully qualified names; in case of severe
  1282 backward campatibility problems try setting 'global_names' at compile
  1283 time to have enrything declared within a flat name space; one may also
  1284 fine tune name declarations in theories via the 'global' and 'local'
  1285 section;
  1286 
  1287 * reimplemented the implicit simpset and claset using the new anytype
  1288 data filed in signatures; references simpset:simpset ref etc. are
  1289 replaced by functions simpset:unit->simpset and
  1290 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1291 to patch your ML files accordingly;
  1292 
  1293 * HTML output now includes theory graph data for display with Java
  1294 applet or isatool browser; data generated automatically via isatool
  1295 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1296 
  1297 * defs may now be conditional; improved rewrite_goals_tac to handle
  1298 conditional equations;
  1299 
  1300 * defs now admits additional type arguments, using TYPE('a) syntax;
  1301 
  1302 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1303 creates a new theory node; implicit merge of thms' signatures is
  1304 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1305 transfer:theory->thm->thm in (rare) cases;
  1306 
  1307 * improved handling of draft signatures / theories; draft thms (and
  1308 ctyps, cterms) are automatically promoted to real ones;
  1309 
  1310 * slightly changed interfaces for oracles: admit many per theory, named
  1311 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1312 
  1313 * print_goals: optional output of const types (set show_consts and
  1314 show_types);
  1315 
  1316 * improved output of warnings (###) and errors (***);
  1317 
  1318 * subgoal_tac displays a warning if the new subgoal has type variables;
  1319 
  1320 * removed old README and Makefiles;
  1321 
  1322 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1323 
  1324 * removed obsolete init_pps and init_database;
  1325 
  1326 * deleted the obsolete tactical STATE, which was declared by
  1327     fun STATE tacfun st = tacfun st st;
  1328 
  1329 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1330 (which abbreviates $HOME);
  1331 
  1332 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1333 use isatool fixseq to adapt your ML programs (this works for fully
  1334 qualified references to the Sequence structure only!);
  1335 
  1336 * use_thy no longer requires writable current directory; it always
  1337 reloads .ML *and* .thy file, if either one is out of date;
  1338 
  1339 
  1340 *** Classical Reasoner ***
  1341 
  1342 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1343 tactics that use classical reasoning to simplify a subgoal without
  1344 splitting it into several subgoals;
  1345 
  1346 * Safe_tac: like safe_tac but uses the default claset;
  1347 
  1348 
  1349 *** Simplifier ***
  1350 
  1351 * added simplification meta rules:
  1352     (asm_)(full_)simplify: simpset -> thm -> thm;
  1353 
  1354 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1355 logics (again);
  1356 
  1357 * added prems argument to simplification procedures;
  1358 
  1359 * HOL, FOL, ZF: added infix function `addsplits':
  1360   instead of `<simpset> setloop (split_tac <thms>)'
  1361   you can simply write `<simpset> addsplits <thms>'
  1362 
  1363 
  1364 *** Syntax ***
  1365 
  1366 * TYPE('a) syntax for type reflection terms;
  1367 
  1368 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1369 
  1370 * pretty printer: changed order of mixfix annotation preference (again!);
  1371 
  1372 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1373 
  1374 
  1375 *** HOL ***
  1376 
  1377 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1378   with `addloop' of the simplifier to faciliate case splitting in premises.
  1379 
  1380 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1381 
  1382 * HOL/Auth: new protocol proofs including some for the Internet
  1383   protocol TLS;
  1384 
  1385 * HOL/Map: new theory of `maps' a la VDM;
  1386 
  1387 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1388 cancelling out common nat summands from =, <, <= (in)equalities, or
  1389 differences; simplification procedures nat_cancel_factor for
  1390 cancelling common factor from =, <, <= (in)equalities over natural
  1391 sums; nat_cancel contains both kinds of procedures, it is installed by
  1392 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1393 
  1394 * HOL/simplifier: terms of the form
  1395   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1396   are rewritten to
  1397   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1398   and those of the form
  1399   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1400   are rewritten to
  1401   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1402 
  1403 * HOL/datatype
  1404   Each datatype `t' now comes with a theorem `split_t_case' 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 
  1412   and a theorem `split_t_case_asm' of the form
  1413 
  1414   P(t_case f1 ... fn x) =
  1415     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1416         ...
  1417        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1418      )
  1419   which can be added to a simpset via `addsplits'. The existing theorems
  1420   expand_list_case and expand_option_case have been renamed to
  1421   split_list_case and split_option_case.
  1422 
  1423 * HOL/Arithmetic:
  1424   - `pred n' is automatically converted to `n-1'.
  1425     Users are strongly encouraged not to use `pred' any longer,
  1426     because it will disappear altogether at some point.
  1427   - Users are strongly encouraged to write "0 < n" rather than
  1428     "n ~= 0". Theorems and proof tools have been modified towards this
  1429     `standard'.
  1430 
  1431 * HOL/Lists:
  1432   the function "set_of_list" has been renamed "set" (and its theorems too);
  1433   the function "nth" now takes its arguments in the reverse order and
  1434   has acquired the infix notation "!" as in "xs!n".
  1435 
  1436 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1437 
  1438 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1439   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1440 
  1441 * HOL/record: extensible records with schematic structural subtyping
  1442 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1443 still lacks various theorems and concrete record syntax;
  1444 
  1445 
  1446 *** HOLCF ***
  1447 
  1448 * removed "axioms" and "generated by" sections;
  1449 
  1450 * replaced "ops" section by extended "consts" section, which is capable of
  1451   handling the continuous function space "->" directly;
  1452 
  1453 * domain package:
  1454   . proves theorems immediately and stores them in the theory,
  1455   . creates hierachical name space,
  1456   . now uses normal mixfix annotations (instead of cinfix...),
  1457   . minor changes to some names and values (for consistency),
  1458   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1459   . separator between mutual domain defs: changed "," to "and",
  1460   . improved handling of sort constraints;  now they have to
  1461     appear on the left-hand side of the equations only;
  1462 
  1463 * fixed LAM <x,y,zs>.b syntax;
  1464 
  1465 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1466 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1467 
  1468 
  1469 *** FOL and ZF ***
  1470 
  1471 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1472   with `addloop' of the simplifier to faciliate case splitting in premises.
  1473 
  1474 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1475 in HOL, they strip ALL and --> from proved theorems;
  1476 
  1477 
  1478 
  1479 New in Isabelle94-8 (May 1997)
  1480 ------------------------------
  1481 
  1482 *** General Changes ***
  1483 
  1484 * new utilities to build / run / maintain Isabelle etc. (in parts
  1485 still somewhat experimental); old Makefiles etc. still functional;
  1486 
  1487 * new 'Isabelle System Manual';
  1488 
  1489 * INSTALL text, together with ./configure and ./build scripts;
  1490 
  1491 * reimplemented type inference for greater efficiency, better error
  1492 messages and clean internal interface;
  1493 
  1494 * prlim command for dealing with lots of subgoals (an easier way of
  1495 setting goals_limit);
  1496 
  1497 
  1498 *** Syntax ***
  1499 
  1500 * supports alternative (named) syntax tables (parser and pretty
  1501 printer); internal interface is provided by add_modesyntax(_i);
  1502 
  1503 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1504 be used in conjunction with the Isabelle symbol font; uses the
  1505 "symbols" syntax table;
  1506 
  1507 * added token_translation interface (may translate name tokens in
  1508 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1509 the current print_mode); IMPORTANT: user print translation functions
  1510 are responsible for marking newly introduced bounds
  1511 (Syntax.mark_boundT);
  1512 
  1513 * token translations for modes "xterm" and "xterm_color" that display
  1514 names in bold, underline etc. or colors (which requires a color
  1515 version of xterm);
  1516 
  1517 * infixes may now be declared with names independent of their syntax;
  1518 
  1519 * added typed_print_translation (like print_translation, but may
  1520 access type of constant);
  1521 
  1522 
  1523 *** Classical Reasoner ***
  1524 
  1525 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1526 some limitations.  Blast_tac...
  1527   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1528   + ignores elimination rules that don't have the correct format
  1529         (the conclusion MUST be a formula variable)
  1530   + ignores types, which can make HOL proofs fail
  1531   + rules must not require higher-order unification, e.g. apply_type in ZF
  1532     [message "Function Var's argument not a bound variable" relates to this]
  1533   + its proof strategy is more general but can actually be slower
  1534 
  1535 * substitution with equality assumptions no longer permutes other
  1536 assumptions;
  1537 
  1538 * minor changes in semantics of addafter (now called addaltern); renamed
  1539 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1540 (and access functions for it);
  1541 
  1542 * improved combination of classical reasoner and simplifier:
  1543   + functions for handling clasimpsets
  1544   + improvement of addss: now the simplifier is called _after_ the
  1545     safe steps.
  1546   + safe variant of addss called addSss: uses safe simplifications
  1547     _during_ the safe steps. It is more complete as it allows multiple
  1548     instantiations of unknowns (e.g. with slow_tac).
  1549 
  1550 *** Simplifier ***
  1551 
  1552 * added interface for simplification procedures (functions that
  1553 produce *proven* rewrite rules on the fly, depending on current
  1554 redex);
  1555 
  1556 * ordering on terms as parameter (used for ordered rewriting);
  1557 
  1558 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1559 
  1560 * the solver is now split into a safe and an unsafe part.
  1561 This should be invisible for the normal user, except that the
  1562 functions setsolver and addsolver have been renamed to setSolver and
  1563 addSolver; added safe_asm_full_simp_tac;
  1564 
  1565 
  1566 *** HOL ***
  1567 
  1568 * a generic induction tactic `induct_tac' which works for all datatypes and
  1569 also for type `nat';
  1570 
  1571 * a generic case distinction tactic `exhaust_tac' which works for all
  1572 datatypes and also for type `nat';
  1573 
  1574 * each datatype comes with a function `size';
  1575 
  1576 * patterns in case expressions allow tuple patterns as arguments to
  1577 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1578 
  1579 * primrec now also works with type nat;
  1580 
  1581 * recdef: a new declaration form, allows general recursive functions to be
  1582 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1583 
  1584 * the constant for negation has been renamed from "not" to "Not" to
  1585 harmonize with FOL, ZF, LK, etc.;
  1586 
  1587 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1588 infinite lists;
  1589 
  1590 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1591 
  1592 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1593 problems in commutative rings, using axiomatic type classes for + and *;
  1594 
  1595 * more examples in HOL/MiniML and HOL/Auth;
  1596 
  1597 * more default rewrite rules for quantifiers, union/intersection;
  1598 
  1599 * a new constant `arbitrary == @x.False';
  1600 
  1601 * HOLCF/IOA replaces old HOL/IOA;
  1602 
  1603 * HOLCF changes: derived all rules and arities
  1604   + axiomatic type classes instead of classes
  1605   + typedef instead of faking type definitions
  1606   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1607   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1608   + eliminated the types void, one, tr
  1609   + use unit lift and bool lift (with translations) instead of one and tr
  1610   + eliminated blift from Lift3.thy (use Def instead of blift)
  1611   all eliminated rules are derived as theorems --> no visible changes ;
  1612 
  1613 
  1614 *** ZF ***
  1615 
  1616 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1617 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1618 as ZF_cs addSIs [equalityI];
  1619 
  1620 
  1621 
  1622 New in Isabelle94-7 (November 96)
  1623 ---------------------------------
  1624 
  1625 * allowing negative levels (as offsets) in prlev and choplev;
  1626 
  1627 * super-linear speedup for large simplifications;
  1628 
  1629 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1630 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1631 FAIL); can suppress it using the command Delsimps (ex_simps @
  1632 all_simps); De Morgan laws are also now included, by default;
  1633 
  1634 * improved printing of ==>  :  ~:
  1635 
  1636 * new object-logic "Sequents" adds linear logic, while replacing LK
  1637 and Modal (thanks to Sara Kalvala);
  1638 
  1639 * HOL/Auth: correctness proofs for authentication protocols;
  1640 
  1641 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1642 examples on HOL/Auth);
  1643 
  1644 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1645 the rewriter and classical reasoner simultaneously;
  1646 
  1647 * function uresult no longer returns theorems in "standard" format;
  1648 regain previous version by: val uresult = standard o uresult;
  1649 
  1650 
  1651 
  1652 New in Isabelle94-6
  1653 -------------------
  1654 
  1655 * oracles -- these establish an interface between Isabelle and trusted
  1656 external reasoners, which may deliver results as theorems;
  1657 
  1658 * proof objects (in particular record all uses of oracles);
  1659 
  1660 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1661 
  1662 * "constdefs" section in theory files;
  1663 
  1664 * "primrec" section (HOL) no longer requires names;
  1665 
  1666 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1667 
  1668 
  1669 
  1670 New in Isabelle94-5
  1671 -------------------
  1672 
  1673 * reduced space requirements;
  1674 
  1675 * automatic HTML generation from theories;
  1676 
  1677 * theory files no longer require "..." (quotes) around most types;
  1678 
  1679 * new examples, including two proofs of the Church-Rosser theorem;
  1680 
  1681 * non-curried (1994) version of HOL is no longer distributed;
  1682 
  1683 
  1684 
  1685 New in Isabelle94-4
  1686 -------------------
  1687 
  1688 * greatly reduced space requirements;
  1689 
  1690 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1691 
  1692 * searchable theorem database (see the section "Retrieving theorems" on
  1693 page 8 of the Reference Manual);
  1694 
  1695 * new examples, including Grabczewski's monumental case study of the
  1696 Axiom of Choice;
  1697 
  1698 * The previous version of HOL renamed to Old_HOL;
  1699 
  1700 * The new version of HOL (previously called CHOL) uses a curried syntax
  1701 for functions.  Application looks like f a b instead of f(a,b);
  1702 
  1703 * Mutually recursive inductive definitions finally work in HOL;
  1704 
  1705 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1706 translates to the operator "split";
  1707 
  1708 
  1709 
  1710 New in Isabelle94-3
  1711 -------------------
  1712 
  1713 * new infix operator, addss, allowing the classical reasoner to
  1714 perform simplification at each step of its search.  Example:
  1715         fast_tac (cs addss ss)
  1716 
  1717 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1718 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1719 look like (a,b) instead of <a,b>;
  1720 
  1721 * PLEASE NOTE: CHOL will eventually replace HOL!
  1722 
  1723 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1724 It translates to the operator "split".  A new theory of integers is available;
  1725 
  1726 * In ZF, integer numerals now denote two's-complement binary integers.
  1727 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1728 
  1729 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1730 of the Axiom of Choice;
  1731 
  1732 
  1733 
  1734 New in Isabelle94-2
  1735 -------------------
  1736 
  1737 * Significantly faster resolution;
  1738 
  1739 * the different sections in a .thy file can now be mixed and repeated
  1740 freely;
  1741 
  1742 * Database of theorems for FOL, HOL and ZF.  New
  1743 commands including qed, qed_goal and bind_thm store theorems in the database.
  1744 
  1745 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1746 a given theory (thms_of), or find out what theory a theorem was proved in
  1747 (theory_of_thm);
  1748 
  1749 * Bugs fixed in the inductive definition and datatype packages;
  1750 
  1751 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1752 and HOL_dup_cs obsolete;
  1753 
  1754 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1755 have been removed;
  1756 
  1757 * Simpler definition of function space in ZF;
  1758 
  1759 * new results about cardinal and ordinal arithmetic in ZF;
  1760 
  1761 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1762 types;
  1763 
  1764 
  1765 $Id$