NEWS
author wenzelm
Mon Feb 05 14:40:21 2001 +0100 (2001-02-05)
changeset 11066 ceab8d437b96
parent 11062 e86340dc1d28
child 11091 45ffef3d3e75
permissions -rw-r--r--
tuned;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle99-2 (February 2001)
     6 -----------------------------------
     7 
     8 *** Overview of INCOMPATIBILITIES ***
     9 
    10 * HOL: inductive package no longer splits induction rule aggressively,
    11 but only as far as specified by the introductions given; the old
    12 format may recovered via ML function complete_split_rule or attribute
    13 'split_rule (complete)';
    14 
    15 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
    16 gfp_Tarski to gfp_unfold;
    17 
    18 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
    19 
    20 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
    21 relation); infix "^^" has been renamed "``"; infix "``" has been
    22 renamed "`"; "univalent" has been renamed "single_valued";
    23 
    24 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
    25 operation;
    26 
    27 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
    28 
    29 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
    30 
    31 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
    32 consequence, it is no longer monotonic wrt. the local goal context
    33 (which is now passed through the inductive cases);
    34 
    35 * Document preparation: renamed standard symbols \<ll> to \<lless> and
    36 \<gg> to \<ggreater>;
    37 
    38 
    39 *** Document preparation ***
    40 
    41 * \isabellestyle{NAME} selects version of Isabelle output (currently
    42 available: are "it" for near math-mode best-style output, "sl" for
    43 slanted text style, and "tt" for plain type-writer; if no
    44 \isabellestyle command is given, output is according to slanted
    45 type-writer);
    46 
    47 * support sub/super scripts (for single symbols only), input syntax is
    48 like this: "A\<^sup>*" or "A\<^sup>\<star>";
    49 
    50 * some more standard symbols; see Appendix A of the system manual for
    51 the complete list of symbols defined in isabellesym.sty;
    52 
    53 * improved isabelle style files; more abstract symbol implementation
    54 (should now use \isamath{...} and \isatext{...} in custom symbol
    55 definitions);
    56 
    57 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
    58 state; Note that presentation of goal states does not conform to
    59 actual human-readable proof documents.  Please do not include goal
    60 states into document output unless you really know what you are doing!
    61 
    62 * proper indentation of antiquoted output with proportional LaTeX
    63 fonts;
    64 
    65 * no_document ML operator temporarily disables LaTeX document
    66 generation;
    67 
    68 * isatool unsymbolize tunes sources for plain ASCII communication;
    69 
    70 
    71 *** Isar ***
    72 
    73 * Pure: Isar now suffers initial goal statements to contain unbound
    74 schematic variables (this does not conform to actual readable proof
    75 documents, due to unpredictable outcome and non-compositional proof
    76 checking); users who know what they are doing may use schematic goals
    77 for Prolog-style synthesis of proven results;
    78 
    79 * Pure: assumption method (an implicit finishing) now handles actual
    80 rules as well;
    81 
    82 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
    83 initial goal, declare "that" only as Pure intro (only for single
    84 steps); the "that" rule assumption may now be involved in implicit
    85 finishing, thus ".." becomes a feasible for trivial obtains;
    86 
    87 * Pure: default proof step now includes 'intro_classes'; thus trivial
    88 instance proofs may be performed by "..";
    89 
    90 * Pure: ?thesis / ?this / "..." now work for pure meta-level
    91 statements as well;
    92 
    93 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
    94 rule (as well as the assumption rule);
    95 
    96 * Pure: 'thm_deps' command visualizes dependencies of theorems and
    97 lemmas, using the graph browser tool;
    98 
    99 * Pure: predict failure of "show" in interactive mode;
   100 
   101 * Pure: 'thms_containing' now takes actual terms as arguments;
   102 
   103 * HOL: improved method 'induct' --- now handles non-atomic goals
   104 (potential INCOMPATIBILITY); tuned error handling;
   105 
   106 * HOL: cases and induct rules now provide explicit hints about the
   107 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   108 any remaining facts are inserted into the goal verbatim;
   109 
   110 * HOL: local contexts (aka cases) may now contain term bindings as
   111 well; the 'cases' and 'induct' methods new provide a ?case binding for
   112 the result to be shown in each case;
   113 
   114 * HOL: added 'recdef_tc' command;
   115 
   116 * isatool convert assists in eliminating legacy ML scripts;
   117 
   118 
   119 *** HOL ***
   120 
   121 * HOL/Library: a collection of generic theories to be used together
   122 with main HOL; the theory loader path already includes this directory
   123 by default; the following existing theories have been moved here:
   124 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   125 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   126 
   127 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   128 modelling and verification task performed in Isabelle/HOL +
   129 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   130 
   131 * HOL basics: added overloaded operations "inverse" and "divide"
   132 (infix "/"), syntax for generic "abs" operation, generic summation
   133 operator;
   134 
   135 * HOL/typedef: simplified package, provide more useful rules (see also
   136 HOL/subset.thy);
   137 
   138 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   139 now expressed as a proper nested rule (old-style tactic scripts may
   140 require atomize_strip_tac to cope with non-atomic premises);
   141 
   142 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   143 to "split_conv" (old name still available for compatibility);
   144 
   145 * HOL: improved concrete syntax for strings (e.g. allows translation
   146 rules with string literals);
   147 
   148 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   149 and Fleuriot's mechanization of analysis;
   150 
   151 * HOL-Real, HOL-Hyperreals: improved arithmetic simplification;
   152 
   153 
   154 *** CTT ***
   155 
   156 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   157 "lam" is displayed as TWO lambda-symbols
   158 
   159 * CTT: theory Main now available, containing everything (that is, Bool
   160 and Arith);
   161 
   162 
   163 *** General ***
   164 
   165 * print modes "brackets" and "no_brackets" control output of nested =>
   166 (types) and ==> (props); the default behaviour is "brackets";
   167 
   168 * system: support Poly/ML 4.0;
   169 
   170 * Pure: the Simplifier has been implemented properly as a derived rule
   171 outside of the actual kernel (at last!); the overall performance
   172 penalty in practical applications is about 50%, while reliability of
   173 the Isabelle inference kernel has been greatly improved;
   174 
   175 * Provers: fast_tac (and friends) now handle actual object-logic rules
   176 as assumptions as well;
   177 
   178 
   179 
   180 New in Isabelle99-1 (October 2000)
   181 ----------------------------------
   182 
   183 *** Overview of INCOMPATIBILITIES ***
   184 
   185 * HOL: simplification of natural numbers is much changed; to partly
   186 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   187 issue the following ML commands:
   188 
   189   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   190   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   191 
   192 * HOL: simplification no longer dives into case-expressions; this is
   193 controlled by "t.weak_case_cong" for each datatype t;
   194 
   195 * HOL: nat_less_induct renamed to less_induct;
   196 
   197 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   198 fixsome to patch .thy and .ML sources automatically;
   199 
   200   select_equality  -> some_equality
   201   select_eq_Ex     -> some_eq_ex
   202   selectI2EX       -> someI2_ex
   203   selectI2         -> someI2
   204   selectI          -> someI
   205   select1_equality -> some1_equality
   206   Eps_sym_eq       -> some_sym_eq_trivial
   207   Eps_eq           -> some_eq_trivial
   208 
   209 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   210 
   211 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   212 instead);
   213 
   214 * HOL: the recursion equations generated by 'recdef' are now called
   215 f.simps instead of f.rules;
   216 
   217 * HOL: qed_spec_mp now also handles bounded ALL as well;
   218 
   219 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   220 sometimes be needed;
   221 
   222 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   223 
   224 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   225 
   226 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   227 product is now "<*>" instead of "Times"; the lexicographic product is
   228 now "<*lex*>" instead of "**";
   229 
   230 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   231 of main HOL, but was unused); better use HOL's datatype package;
   232 
   233 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   234 the old syntax may be recovered as follows:
   235 
   236   syntax (symbols)
   237     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   238       (infixl "\\<oplus>" 100)
   239 
   240 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   241 
   242 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   243 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   244 internally;
   245 
   246 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   247 changed from A/r to A//r;
   248 
   249 * ZF: new treatment of arithmetic (nat & int) may break some old
   250 proofs;
   251 
   252 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   253 rulify -> rule_format, elimify -> elim_format, ...);
   254 
   255 * Isar/Provers: intro/elim/dest attributes changed; renamed
   256 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   257 should have to change intro!! to intro? only); replaced "delrule" by
   258 "rule del";
   259 
   260 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   261 
   262 * Provers: strengthened force_tac by using new first_best_tac;
   263 
   264 * LaTeX document preparation: several changes of isabelle.sty (see
   265 lib/texinputs);
   266 
   267 
   268 *** Document preparation ***
   269 
   270 * formal comments (text blocks etc.) in new-style theories may now
   271 contain antiquotations of thm/prop/term/typ/text to be presented
   272 according to latex print mode; concrete syntax is like this:
   273 @{term[show_types] "f(x) = a + x"};
   274 
   275 * isatool mkdir provides easy setup of Isabelle session directories,
   276 including proper document sources;
   277 
   278 * generated LaTeX sources are now deleted after successful run
   279 (isatool document -c); may retain a copy somewhere else via -D option
   280 of isatool usedir;
   281 
   282 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   283 style files, achieving self-contained LaTeX sources and simplifying
   284 LaTeX debugging;
   285 
   286 * old-style theories now produce (crude) LaTeX output as well;
   287 
   288 * browser info session directories are now self-contained (may be put
   289 on WWW server seperately); improved graphs of nested sessions; removed
   290 graph for 'all sessions';
   291 
   292 * several improvements in isabelle style files; \isabellestyle{it}
   293 produces fake math mode output; \isamarkupheader is now \section by
   294 default; see lib/texinputs/isabelle.sty etc.;
   295 
   296 
   297 *** Isar ***
   298 
   299 * Isar/Pure: local results and corresponding term bindings are now
   300 subject to Hindley-Milner polymorphism (similar to ML); this
   301 accommodates incremental type-inference very nicely;
   302 
   303 * Isar/Pure: new derived language element 'obtain' supports
   304 generalized existence reasoning;
   305 
   306 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   307 support accumulation of results, without applying any rules yet;
   308 useful to collect intermediate results without explicit name
   309 references, and for use with transitivity rules with more than 2
   310 premises;
   311 
   312 * Isar/Pure: scalable support for case-analysis type proofs: new
   313 'case' language element refers to local contexts symbolically, as
   314 produced by certain proof methods; internally, case names are attached
   315 to theorems as "tags";
   316 
   317 * Isar/Pure: theory command 'hide' removes declarations from
   318 class/type/const name spaces;
   319 
   320 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   321 indicate potential overloading;
   322 
   323 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   324 
   325 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   326 "{a,b,c}" instead of {a,b,c};
   327 
   328 * Isar/Pure now provides its own version of intro/elim/dest
   329 attributes; useful for building new logics, but beware of confusion
   330 with the version in Provers/classical;
   331 
   332 * Isar/Pure: the local context of (non-atomic) goals is provided via
   333 case name 'antecedent';
   334 
   335 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   336 to the current context is now done automatically);
   337 
   338 * Isar/Pure: theory command 'method_setup' provides a simple interface
   339 for definining proof methods in ML;
   340 
   341 * Isar/Provers: intro/elim/dest attributes changed; renamed
   342 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   343 most cases, one should have to change intro!! to intro? only);
   344 replaced "delrule" by "rule del";
   345 
   346 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   347 'symmetric' attribute (the latter supercedes [RS sym]);
   348 
   349 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   350 method modifier); 'simp' method: 'only:' modifier removes loopers as
   351 well (including splits);
   352 
   353 * Isar/Provers: Simplifier and Classical methods now support all kind
   354 of modifiers used in the past, including 'cong', 'iff', etc.
   355 
   356 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   357 of Simplifier and Classical reasoner);
   358 
   359 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   360 now support named cases; major packages (inductive, datatype, primrec,
   361 recdef) support case names and properly name parameters;
   362 
   363 * Isar/HOL: new transitivity rules for substitution in inequalities --
   364 monotonicity conditions are extracted to be proven at end of
   365 calculations;
   366 
   367 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   368 method anyway;
   369 
   370 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   371 split_if split_if_asm; datatype package provides theorems foo.splits =
   372 foo.split foo.split_asm for each datatype;
   373 
   374 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   375 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   376 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   377 use "(cases (simplified))" method in proper proof texts);
   378 
   379 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   380 
   381 * Isar: names of theorems etc. may be natural numbers as well;
   382 
   383 * Isar: 'pr' command: optional arguments for goals_limit and
   384 ProofContext.prems_limit; no longer prints theory contexts, but only
   385 proof states;
   386 
   387 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   388 additional print modes to be specified; e.g. "pr(latex)" will print
   389 proof state according to the Isabelle LaTeX style;
   390 
   391 * Isar: improved support for emulating tactic scripts, including proof
   392 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   393 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   394 (for HOL datatypes);
   395 
   396 * Isar: simplified (more robust) goal selection of proof methods: 1st
   397 goal, all goals, or explicit goal specifier (tactic emulation); thus
   398 'proof method scripts' have to be in depth-first order;
   399 
   400 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   401 
   402 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   403 should instead use individual commands for printing items
   404 (print_commands, print_methods etc.);
   405 
   406 * Isar: added 'nothing' --- the empty list of theorems;
   407 
   408 
   409 *** HOL ***
   410 
   411 * HOL/MicroJava: formalization of a fragment of Java, together with a
   412 corresponding virtual machine and a specification of its bytecode
   413 verifier and a lightweight bytecode verifier, including proofs of
   414 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   415 Cornelia Pusch (see also the homepage of project Bali at
   416 http://isabelle.in.tum.de/Bali/);
   417 
   418 * HOL/Algebra: new theory of rings and univariate polynomials, by
   419 Clemens Ballarin;
   420 
   421 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   422 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   423 Rasmussen;
   424 
   425 * HOL/Lattice: fundamental concepts of lattice theory and order
   426 structures, including duals, properties of bounds versus algebraic
   427 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   428 Theorem for complete lattices etc.; may also serve as a demonstration
   429 for abstract algebraic reasoning using axiomatic type classes, and
   430 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   431 
   432 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   433 von Oheimb;
   434 
   435 * HOL/IMPP: extension of IMP with local variables and mutually
   436 recursive procedures, by David von Oheimb;
   437 
   438 * HOL/Lambda: converted into new-style theory and document;
   439 
   440 * HOL/ex/Multiquote: example of multiple nested quotations and
   441 anti-quotations -- basically a generalized version of de-Bruijn
   442 representation; very useful in avoiding lifting of operations;
   443 
   444 * HOL/record: added general record equality rule to simpset; fixed
   445 select-update simplification procedure to handle extended records as
   446 well; admit "r" as field name;
   447 
   448 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   449 other numeric types and also as the identity of groups, rings, etc.;
   450 
   451 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   452 Types nat and int belong to this axclass;
   453 
   454 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   455    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   456    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   457   two terms #m*u and #n*u are replaced by #(m+n)*u
   458     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   459   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   460     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   461 
   462 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   463 powerful prover for predicate logic but knows nothing of clasets; see
   464 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   465 
   466 * HOL: new version of "case_tac" subsumes both boolean case split and
   467 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   468 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   469 
   470 * HOL: simplification no longer dives into case-expressions: only the
   471 selector expression is simplified, but not the remaining arms; to
   472 enable full simplification of case-expressions for datatype t, you may
   473 remove t.weak_case_cong from the simpset, either globally (Delcongs
   474 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   475 
   476 * HOL/recdef: the recursion equations generated by 'recdef' for
   477 function 'f' are now called f.simps instead of f.rules; if all
   478 termination conditions are proved automatically, these simplification
   479 rules are added to the simpset, as in primrec; rules may be named
   480 individually as well, resulting in a separate list of theorems for
   481 each equation;
   482 
   483 * HOL/While is a new theory that provides a while-combinator. It
   484 permits the definition of tail-recursive functions without the
   485 provision of a termination measure. The latter is necessary once the
   486 invariant proof rule for while is applied.
   487 
   488 * HOL: new (overloaded) notation for the set of elements below/above
   489 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   490 
   491 * HOL: theorems impI, allI, ballI bound as "strip";
   492 
   493 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   494 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   495 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   496 
   497 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   498 
   499 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   500 main HOL, but was unused);
   501 
   502 * HOL: fewer consts declared as global (e.g. have to refer to
   503 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   504 
   505 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   506 in case of overlap with user translations (e.g. judgements over
   507 tuples); (note that the underlying logical represenation is still
   508 bogus);
   509 
   510 
   511 *** ZF ***
   512 
   513 * ZF: simplification automatically cancels common terms in arithmetic
   514 expressions over nat and int;
   515 
   516 * ZF: new treatment of nat to minimize type-checking: all operators
   517 coerce their operands to a natural number using the function natify,
   518 making the algebraic laws unconditional;
   519 
   520 * ZF: as above, for int: operators coerce their operands to an integer
   521 using the function intify;
   522 
   523 * ZF: the integer library now contains many of the usual laws for the
   524 orderings, including $<=, and monotonicity laws for $+ and $*;
   525 
   526 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   527 simplification;
   528 
   529 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   530 to the simplifier and classical reasoner simultaneously;
   531 
   532 
   533 *** General ***
   534 
   535 * Provers: blast_tac now handles actual object-logic rules as
   536 assumptions; note that auto_tac uses blast_tac internally as well;
   537 
   538 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   539 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   540 
   541 * Provers: delrules now handles destruct rules as well (no longer need
   542 explicit make_elim);
   543 
   544 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   545   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   546 use instead the strong form,
   547   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   548 in HOL, FOL and ZF the function cla_make_elim will create such rules
   549 from destruct-rules;
   550 
   551 * Provers: Simplifier.easy_setup provides a fast path to basic
   552 Simplifier setup for new object-logics;
   553 
   554 * Pure: AST translation rules no longer require constant head on LHS;
   555 
   556 * Pure: improved name spaces: ambiguous output is qualified; support
   557 for hiding of names;
   558 
   559 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   560 XSYMBOL_HOME; no longer need to do manual configuration in most
   561 situations;
   562 
   563 * system: compression of ML heaps images may now be controlled via -c
   564 option of isabelle and isatool usedir (currently only observed by
   565 Poly/ML);
   566 
   567 * system: isatool installfonts may handle X-Symbol fonts as well (very
   568 useful for remote X11);
   569 
   570 * system: provide TAGS file for Isabelle sources;
   571 
   572 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   573 order;
   574 
   575 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   576 timing flag supersedes proof_timing and Toplevel.trace;
   577 
   578 * ML: new combinators |>> and |>>> for incremental transformations
   579 with secondary results (e.g. certain theory extensions):
   580 
   581 * ML: PureThy.add_defs gets additional argument to indicate potential
   582 overloading (usually false);
   583 
   584 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   585 results;
   586 
   587 
   588 
   589 New in Isabelle99 (October 1999)
   590 --------------------------------
   591 
   592 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   593 
   594 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   595 are no longer simplified.  (This allows the simplifier to unfold recursive
   596 functional programs.)  To restore the old behaviour, declare
   597 
   598     Delcongs [if_weak_cong];
   599 
   600 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   601 complement;
   602 
   603 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   604 
   605 * HOL/datatype: mutual_induct_tac no longer exists --
   606   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   607 
   608 * HOL/typedef: fixed type inference for representing set; type
   609 arguments now have to occur explicitly on the rhs as type constraints;
   610 
   611 * ZF: The con_defs part of an inductive definition may no longer refer
   612 to constants declared in the same theory;
   613 
   614 * HOL, ZF: the function mk_cases, generated by the inductive
   615 definition package, has lost an argument.  To simplify its result, it
   616 uses the default simpset instead of a supplied list of theorems.
   617 
   618 * HOL/List: the constructors of type list are now Nil and Cons;
   619 
   620 * Simplifier: the type of the infix ML functions
   621         setSSolver addSSolver setSolver addSolver
   622 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   623 for packaging solvers. A solver is created via
   624         mk_solver: string -> (thm list -> int -> tactic) -> solver
   625 where the string argument is only a comment.
   626 
   627 
   628 *** Proof tools ***
   629 
   630 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   631 decision procedure for linear arithmetic. Currently it is used for
   632 types `nat', `int', and `real' in HOL (see below); it can, should and
   633 will be instantiated for other types and logics as well.
   634 
   635 * The simplifier now accepts rewrite rules with flexible heads, eg
   636      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   637   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   638   matching.
   639 
   640 
   641 *** General ***
   642 
   643 * New Isabelle/Isar subsystem provides an alternative to traditional
   644 tactical theorem proving; together with the ProofGeneral/isar user
   645 interface it offers an interactive environment for developing human
   646 readable proof documents (Isar == Intelligible semi-automated
   647 reasoning); for further information see isatool doc isar-ref,
   648 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   649 
   650 * improved and simplified presentation of theories: better HTML markup
   651 (including colors), graph views in several sizes; isatool usedir now
   652 provides a proper interface for user theories (via -P option); actual
   653 document preparation based on (PDF)LaTeX is available as well (for
   654 new-style theories only); see isatool doc system for more information;
   655 
   656 * native support for Proof General, both for classic Isabelle and
   657 Isabelle/Isar;
   658 
   659 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   660 using the graph browser tool;
   661 
   662 * Isabelle manuals now also available as PDF;
   663 
   664 * theory loader rewritten from scratch (may not be fully
   665 bug-compatible); old loadpath variable has been replaced by show_path,
   666 add_path, del_path, reset_path functions; new operations such as
   667 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   668 isatool doc ref);
   669 
   670 * improved isatool install: option -k creates KDE application icon,
   671 option -p DIR installs standalone binaries;
   672 
   673 * added ML_PLATFORM setting (useful for cross-platform installations);
   674 more robust handling of platform specific ML images for SML/NJ;
   675 
   676 * the settings environment is now statically scoped, i.e. it is never
   677 created again in sub-processes invoked from isabelle, isatool, or
   678 Isabelle;
   679 
   680 * path element specification '~~' refers to '$ISABELLE_HOME';
   681 
   682 * in locales, the "assumes" and "defines" parts may be omitted if
   683 empty;
   684 
   685 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   686 long arrows);
   687 
   688 * new print_mode "HTML";
   689 
   690 * new flag show_tags controls display of tags of theorems (which are
   691 basically just comments that may be attached by some tools);
   692 
   693 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   694 mode and goal output format:
   695 
   696 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   697 244c244
   698 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   699 ---
   700 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   701 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   702 181c181
   703 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   704 ---
   705 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   706 
   707 * function bind_thms stores lists of theorems (cf. bind_thm);
   708 
   709 * new shorthand tactics ftac, eatac, datac, fatac;
   710 
   711 * qed (and friends) now accept "" as result name; in that case the
   712 theorem is not stored, but proper checks and presentation of the
   713 result still apply;
   714 
   715 * theorem database now also indexes constants "Trueprop", "all",
   716 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   717 
   718 
   719 *** HOL ***
   720 
   721 ** HOL arithmetic **
   722 
   723 * There are now decision procedures for linear arithmetic over nat and
   724 int:
   725 
   726 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   727 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   728 are treated as atomic; subformulae not involving type `nat' or `int'
   729 are ignored; quantified subformulae are ignored unless they are
   730 positive universal or negative existential. The tactic has to be
   731 invoked by hand and can be a little bit slow. In particular, the
   732 running time is exponential in the number of occurrences of `min' and
   733 `max', and `-' on `nat'.
   734 
   735 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   736 (negated) (in)equalities among the premises and the conclusion into
   737 account (i.e. no compound formulae) and does not know about `min' and
   738 `max', and `-' on `nat'. It is fast and is used automatically by the
   739 simplifier.
   740 
   741 NB: At the moment, these decision procedures do not cope with mixed
   742 nat/int formulae where the two parts interact, such as `m < n ==>
   743 int(m) < int(n)'.
   744 
   745 * HOL/Numeral provides a generic theory of numerals (encoded
   746 efficiently as bit strings); setup for types nat/int/real is in place;
   747 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   748 int, existing theories and proof scripts may require a few additional
   749 type constraints;
   750 
   751 * integer division and remainder can now be performed on constant
   752 arguments;
   753 
   754 * many properties of integer multiplication, division and remainder
   755 are now available;
   756 
   757 * An interface to the Stanford Validity Checker (SVC) is available through the
   758 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   759 are proved automatically.  SVC must be installed separately, and its results
   760 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   761 invocation of the underlying oracle).  For SVC see
   762   http://verify.stanford.edu/SVC
   763 
   764 * IsaMakefile: the HOL-Real target now builds an actual image;
   765 
   766 
   767 ** HOL misc **
   768 
   769 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   770 (in Isabelle/Isar) -- by Gertrud Bauer;
   771 
   772 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   773 analysis for assembly languages with subtypes;
   774 
   775 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   776 -- avoids syntactic ambiguities and treats state, transition, and
   777 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   778 changed syntax and (many) tactics;
   779 
   780 * HOL/inductive: Now also handles more general introduction rules such
   781   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   782   theorems are now maintained within the theory (maintained via the
   783   "mono" attribute);
   784 
   785 * HOL/datatype: Now also handles arbitrarily branching datatypes
   786   (using function types) such as
   787 
   788   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   789 
   790 * HOL/record: record_simproc (part of the default simpset) takes care
   791 of selectors applied to updated records; record_split_tac is no longer
   792 part of the default claset; update_defs may now be removed from the
   793 simpset in many cases; COMPATIBILITY: old behavior achieved by
   794 
   795   claset_ref () := claset() addSWrapper record_split_wrapper;
   796   Delsimprocs [record_simproc]
   797 
   798 * HOL/typedef: fixed type inference for representing set; type
   799 arguments now have to occur explicitly on the rhs as type constraints;
   800 
   801 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   802 names rather than an ML expression;
   803 
   804 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   805 supplied later.  Program schemes can be defined, such as
   806     "While B C s = (if B s then While B C (C s) else s)"
   807 where the well-founded relation can be chosen after B and C have been given.
   808 
   809 * HOL/List: the constructors of type list are now Nil and Cons;
   810 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   811 course, ML tools referring to List.list.op # etc. have to be adapted;
   812 
   813 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   814 disabled by default; run isabelle with option -m HOL to get back to
   815 the original Gordon/HOL-style output;
   816 
   817 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   818 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   819 
   820 * HOL basic syntax simplified (more orthogonal): all variants of
   821 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   822 Eps operator is provided as well: "SOME x. P[x]";
   823 
   824 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   825 
   826 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   827 thus available for user theories;
   828 
   829 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   830 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   831 time;
   832 
   833 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   834 several times and then mp;
   835 
   836 
   837 *** LK ***
   838 
   839 * the notation <<...>> is now available as a notation for sequences of
   840 formulas;
   841 
   842 * the simplifier is now installed
   843 
   844 * the axiom system has been generalized (thanks to Soren Heilmann)
   845 
   846 * the classical reasoner now has a default rule database
   847 
   848 
   849 *** ZF ***
   850 
   851 * new primrec section allows primitive recursive functions to be given
   852 directly (as in HOL) over datatypes and the natural numbers;
   853 
   854 * new tactics induct_tac and exhaust_tac for induction (or case
   855 analysis) over datatypes and the natural numbers;
   856 
   857 * the datatype declaration of type T now defines the recursor T_rec;
   858 
   859 * simplification automatically does freeness reasoning for datatype
   860 constructors;
   861 
   862 * automatic type-inference, with AddTCs command to insert new
   863 type-checking rules;
   864 
   865 * datatype introduction rules are now added as Safe Introduction rules
   866 to the claset;
   867 
   868 * the syntax "if P then x else y" is now available in addition to
   869 if(P,x,y);
   870 
   871 
   872 *** Internal programming interfaces ***
   873 
   874 * tuned simplifier trace output; new flag debug_simp;
   875 
   876 * structures Vartab / Termtab (instances of TableFun) offer efficient
   877 tables indexed by indexname_ord / term_ord (compatible with aconv);
   878 
   879 * AxClass.axclass_tac lost the theory argument;
   880 
   881 * tuned current_goals_markers semantics: begin / end goal avoids
   882 printing empty lines;
   883 
   884 * removed prs and prs_fn hook, which was broken because it did not
   885 include \n in its semantics, forcing writeln to add one
   886 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   887 string -> unit if you really want to output text without newline;
   888 
   889 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   890 plain output, interface builders may have to enable 'isabelle_font'
   891 mode to get Isabelle font glyphs as before;
   892 
   893 * refined token_translation interface; INCOMPATIBILITY: output length
   894 now of type real instead of int;
   895 
   896 * theory loader actions may be traced via new ThyInfo.add_hook
   897 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   898 your own database of information attached to *whole* theories -- as
   899 opposed to intra-theory data slots offered via TheoryDataFun;
   900 
   901 * proper handling of dangling sort hypotheses (at last!);
   902 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   903 extra sort hypotheses that can be witnessed from the type signature;
   904 the force_strip_shyps flag is gone, any remaining shyps are simply
   905 left in the theorem (with a warning issued by strip_shyps_warning);
   906 
   907 
   908 
   909 New in Isabelle98-1 (October 1998)
   910 ----------------------------------
   911 
   912 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   913 
   914 * several changes of automated proof tools;
   915 
   916 * HOL: major changes to the inductive and datatype packages, including
   917 some minor incompatibilities of theory syntax;
   918 
   919 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   920 called `inj_on';
   921 
   922 * HOL: removed duplicate thms in Arith:
   923   less_imp_add_less  should be replaced by  trans_less_add1
   924   le_imp_add_le      should be replaced by  trans_le_add1
   925 
   926 * HOL: unary minus is now overloaded (new type constraints may be
   927 required);
   928 
   929 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   930 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   931 now taken as an integer constant.
   932 
   933 * Pure: ML function 'theory_of' renamed to 'theory';
   934 
   935 
   936 *** Proof tools ***
   937 
   938 * Simplifier:
   939   1. Asm_full_simp_tac is now more aggressive.
   940      1. It will sometimes reorient premises if that increases their power to
   941         simplify.
   942      2. It does no longer proceed strictly from left to right but may also
   943         rotate premises to achieve further simplification.
   944      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   945      old Asm_full_simp_tac in that it does not rotate premises.
   946   2. The simplifier now knows a little bit about nat-arithmetic.
   947 
   948 * Classical reasoner: wrapper mechanism for the classical reasoner now
   949 allows for selected deletion of wrappers, by introduction of names for
   950 wrapper functionals.  This implies that addbefore, addSbefore,
   951 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   952 and that adding two tactics with the same name overwrites the first
   953 one (emitting a warning).
   954   type wrapper = (int -> tactic) -> (int -> tactic)
   955   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   956   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   957   delWrapper, delSWrapper: claset *  string            -> claset
   958   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   959 
   960 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   961 semantics; addbefore now affects only the unsafe part of step_tac
   962 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   963 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   964 by Force_tac;
   965 
   966 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   967 compWrapper; added safe wrapper (and access functions for it);
   968 
   969 * HOL/split_all_tac is now much faster and fails if there is nothing
   970 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   971 and the names of the automatically generated variables have changed.
   972 split_all_tac has moved within claset() from unsafe wrappers to safe
   973 wrappers, which means that !!-bound variables are split much more
   974 aggressively, and safe_tac and clarify_tac now split such variables.
   975 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   976 Note: the same holds for record_split_tac, which does the job of
   977 split_all_tac for record fields.
   978 
   979 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   980 permanently to the default simpset using Addsplits just like
   981 Addsimps. They can be removed via Delsplits just like
   982 Delsimps. Lower-case versions are also available.
   983 
   984 * HOL/Simplifier: The rule split_if is now part of the default
   985 simpset. This means that the simplifier will eliminate all occurrences
   986 of if-then-else in the conclusion of a goal. To prevent this, you can
   987 either remove split_if completely from the default simpset by
   988 `Delsplits [split_if]' or remove it in a specific call of the
   989 simplifier using `... delsplits [split_if]'.  You can also add/delete
   990 other case splitting rules to/from the default simpset: every datatype
   991 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   992 t is the name of the datatype).
   993 
   994 * Classical reasoner / Simplifier combination: new force_tac (and
   995 derivatives Force_tac, force) combines rewriting and classical
   996 reasoning (and whatever other tools) similarly to auto_tac, but is
   997 aimed to solve the given subgoal completely.
   998 
   999 
  1000 *** General ***
  1001 
  1002 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1003 and `goalw': the theory is no longer needed as an explicit argument -
  1004 the current theory context is used; assumptions are no longer returned
  1005 at the ML-level unless one of them starts with ==> or !!; it is
  1006 recommended to convert to these new commands using isatool fixgoal
  1007 (backup your sources first!);
  1008 
  1009 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1010 the current theory context, and 'theory' to lookup stored theories;
  1011 
  1012 * new theory section 'locale' for declaring constants, assumptions and
  1013 definitions that have local scope;
  1014 
  1015 * new theory section 'nonterminals' for purely syntactic types;
  1016 
  1017 * new theory section 'setup' for generic ML setup functions
  1018 (e.g. package initialization);
  1019 
  1020 * the distribution now includes Isabelle icons: see
  1021 lib/logo/isabelle-{small,tiny}.xpm;
  1022 
  1023 * isatool install - install binaries with absolute references to
  1024 ISABELLE_HOME/bin;
  1025 
  1026 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1027 
  1028 * print mode 'emacs' reserved for Isamode;
  1029 
  1030 * support multiple print (ast) translations per constant name;
  1031 
  1032 * theorems involving oracles are now printed with a suffixed [!];
  1033 
  1034 
  1035 *** HOL ***
  1036 
  1037 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1038 
  1039 * HOL/inductive package reorganized and improved: now supports mutual
  1040 definitions such as
  1041 
  1042   inductive EVEN ODD
  1043     intrs
  1044       null "0 : EVEN"
  1045       oddI "n : EVEN ==> Suc n : ODD"
  1046       evenI "n : ODD ==> Suc n : EVEN"
  1047 
  1048 new theorem list "elims" contains an elimination rule for each of the
  1049 recursive sets; inductive definitions now handle disjunctive premises
  1050 correctly (also ZF);
  1051 
  1052 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1053 "mutual_induct" no longer exists - the induction rule is always
  1054 contained in "induct";
  1055 
  1056 
  1057 * HOL/datatype package re-implemented and greatly improved: now
  1058 supports mutually recursive datatypes such as
  1059 
  1060   datatype
  1061     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1062             | SUM ('a aexp) ('a aexp)
  1063             | DIFF ('a aexp) ('a aexp)
  1064             | NUM 'a
  1065   and
  1066     'a bexp = LESS ('a aexp) ('a aexp)
  1067             | AND ('a bexp) ('a bexp)
  1068             | OR ('a bexp) ('a bexp)
  1069 
  1070 as well as indirectly recursive datatypes such as
  1071 
  1072   datatype
  1073     ('a, 'b) term = Var 'a
  1074                   | App 'b ((('a, 'b) term) list)
  1075 
  1076 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1077 induction on mutually / indirectly recursive datatypes.
  1078 
  1079 Primrec equations are now stored in theory and can be accessed via
  1080 <function_name>.simps.
  1081 
  1082 INCOMPATIBILITIES:
  1083 
  1084   - Theories using datatypes must now have theory Datatype as an
  1085     ancestor.
  1086   - The specific <typename>.induct_tac no longer exists - use the
  1087     generic induct_tac instead.
  1088   - natE has been renamed to nat.exhaust - use exhaust_tac
  1089     instead of res_inst_tac ... natE. Note that the variable
  1090     names in nat.exhaust differ from the names in natE, this
  1091     may cause some "fragile" proofs to fail.
  1092   - The theorems split_<typename>_case and split_<typename>_case_asm
  1093     have been renamed to <typename>.split and <typename>.split_asm.
  1094   - Since default sorts of type variables are now handled correctly,
  1095     some datatype definitions may have to be annotated with explicit
  1096     sort constraints.
  1097   - Primrec definitions no longer require function name and type
  1098     of recursive argument.
  1099 
  1100 Consider using isatool fixdatatype to adapt your theories and proof
  1101 scripts to the new package (backup your sources first!).
  1102 
  1103 
  1104 * HOL/record package: considerably improved implementation; now
  1105 includes concrete syntax for record types, terms, updates; theorems
  1106 for surjective pairing and splitting !!-bound record variables; proof
  1107 support is as follows:
  1108 
  1109   1) standard conversions (selectors or updates applied to record
  1110 constructor terms) are part of the standard simpset;
  1111 
  1112   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1113 made part of standard simpset and claset via addIffs;
  1114 
  1115   3) a tactic for record field splitting (record_split_tac) is part of
  1116 the standard claset (addSWrapper);
  1117 
  1118 To get a better idea about these rules you may retrieve them via
  1119 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1120 the name of your record type.
  1121 
  1122 The split tactic 3) conceptually simplifies by the following rule:
  1123 
  1124   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1125 
  1126 Thus any record variable that is bound by meta-all will automatically
  1127 blow up into some record constructor term, consequently the
  1128 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1129 solve record problems automatically.
  1130 
  1131 
  1132 * reorganized the main HOL image: HOL/Integ and String loaded by
  1133 default; theory Main includes everything;
  1134 
  1135 * automatic simplification of integer sums and comparisons, using cancellation;
  1136 
  1137 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1138 
  1139 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1140 
  1141 * many new identities for unions, intersections, set difference, etc.;
  1142 
  1143 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1144 called split_if, split_split, split_sum_case and split_nat_case (to go
  1145 with add/delsplits);
  1146 
  1147 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1148 (?x::unit) = (); this is made part of the default simpset, which COULD
  1149 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1150 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1151 unit_abs_eta_conv is added in order to counter the effect of
  1152 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1153 %u.f();
  1154 
  1155 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1156 makes more sense);
  1157 
  1158 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1159   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1160   disjointness reasoning but breaking a few old proofs.
  1161 
  1162 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1163 to 'converse' from 'inverse' (for compatibility with ZF and some
  1164 literature);
  1165 
  1166 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1167 the well-founded relation;
  1168 
  1169 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1170     Compl A.  The "Compl" syntax remains available as input syntax for this
  1171     release ONLY.
  1172 
  1173 * HOL/Update: new theory of function updates:
  1174     f(a:=b) == %x. if x=a then b else f x
  1175 may also be iterated as in f(a:=b,c:=d,...);
  1176 
  1177 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1178 
  1179 * HOL/List:
  1180   - new function list_update written xs[i:=v] that updates the i-th
  1181     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1182   - new function `upt' written [i..j(] which generates the list
  1183     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1184     bound write [i..j], which is a shorthand for [i..j+1(].
  1185   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1186 
  1187 * HOL/Arith:
  1188   - removed 'pred' (predecessor) function;
  1189   - generalized some theorems about n-1;
  1190   - many new laws about "div" and "mod";
  1191   - new laws about greatest common divisors (see theory ex/Primes);
  1192 
  1193 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1194 instead of "inverse";
  1195 
  1196 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1197   of the multiset ordering;
  1198 
  1199 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1200   (not included by default);
  1201 
  1202 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1203 
  1204 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1205   programs, i.e. different program variables may have different types.
  1206 
  1207 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1208   [previously, this check worked only if the rewrite rule was unconditional]
  1209   Now rew can involve either definitions or equalities (either == or =).
  1210 
  1211 
  1212 *** ZF ***
  1213 
  1214 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1215   only the theorems proved on ZF.ML;
  1216 
  1217 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1218   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1219   disjointness reasoning but breaking a few old proofs.
  1220 
  1221 * ZF/Update: new theory of function updates
  1222     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1223   may also be iterated as in f(a:=b,c:=d,...);
  1224 
  1225 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1226 
  1227 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1228   [previously, this check worked only if the rewrite rule was unconditional]
  1229   Now rew can involve either definitions or equalities (either == or =).
  1230 
  1231 * case_tac provided for compatibility with HOL
  1232     (like the old excluded_middle_tac, but with subgoals swapped)
  1233 
  1234 
  1235 *** Internal programming interfaces ***
  1236 
  1237 * Pure: several new basic modules made available for general use, see
  1238 also src/Pure/README;
  1239 
  1240 * improved the theory data mechanism to support encapsulation (data
  1241 kind name replaced by private Object.kind, acting as authorization
  1242 key); new type-safe user interface via functor TheoryDataFun; generic
  1243 print_data function becomes basically useless;
  1244 
  1245 * removed global_names compatibility flag -- all theory declarations
  1246 are qualified by default;
  1247 
  1248 * module Pure/Syntax now offers quote / antiquote translation
  1249 functions (useful for Hoare logic etc. with implicit dependencies);
  1250 see HOL/ex/Antiquote for an example use;
  1251 
  1252 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1253 cterm -> thm;
  1254 
  1255 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1256 subgoal;
  1257 
  1258 * Display.print_goals function moved to Locale.print_goals;
  1259 
  1260 * standard print function for goals supports current_goals_markers
  1261 variable for marking begin of proof, end of proof, start of goal; the
  1262 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1263 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1264 for example;
  1265 
  1266 
  1267 
  1268 New in Isabelle98 (January 1998)
  1269 --------------------------------
  1270 
  1271 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1272 
  1273 * changed lexical syntax of terms / types: dots made part of long
  1274 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1275 
  1276 * simpset (and claset) reference variable replaced by functions
  1277 simpset / simpset_ref;
  1278 
  1279 * no longer supports theory aliases (via merge) and non-trivial
  1280 implicit merge of thms' signatures;
  1281 
  1282 * most internal names of constants changed due to qualified names;
  1283 
  1284 * changed Pure/Sequence interface (see Pure/seq.ML);
  1285 
  1286 
  1287 *** General Changes ***
  1288 
  1289 * hierachically structured name spaces (for consts, types, axms, thms
  1290 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1291 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1292 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1293 long_names for fully qualified output names; NOTE: ML programs
  1294 (special tactics, packages etc.) referring to internal names may have
  1295 to be adapted to cope with fully qualified names; in case of severe
  1296 backward campatibility problems try setting 'global_names' at compile
  1297 time to have enrything declared within a flat name space; one may also
  1298 fine tune name declarations in theories via the 'global' and 'local'
  1299 section;
  1300 
  1301 * reimplemented the implicit simpset and claset using the new anytype
  1302 data filed in signatures; references simpset:simpset ref etc. are
  1303 replaced by functions simpset:unit->simpset and
  1304 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1305 to patch your ML files accordingly;
  1306 
  1307 * HTML output now includes theory graph data for display with Java
  1308 applet or isatool browser; data generated automatically via isatool
  1309 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1310 
  1311 * defs may now be conditional; improved rewrite_goals_tac to handle
  1312 conditional equations;
  1313 
  1314 * defs now admits additional type arguments, using TYPE('a) syntax;
  1315 
  1316 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1317 creates a new theory node; implicit merge of thms' signatures is
  1318 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1319 transfer:theory->thm->thm in (rare) cases;
  1320 
  1321 * improved handling of draft signatures / theories; draft thms (and
  1322 ctyps, cterms) are automatically promoted to real ones;
  1323 
  1324 * slightly changed interfaces for oracles: admit many per theory, named
  1325 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1326 
  1327 * print_goals: optional output of const types (set show_consts and
  1328 show_types);
  1329 
  1330 * improved output of warnings (###) and errors (***);
  1331 
  1332 * subgoal_tac displays a warning if the new subgoal has type variables;
  1333 
  1334 * removed old README and Makefiles;
  1335 
  1336 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1337 
  1338 * removed obsolete init_pps and init_database;
  1339 
  1340 * deleted the obsolete tactical STATE, which was declared by
  1341     fun STATE tacfun st = tacfun st st;
  1342 
  1343 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1344 (which abbreviates $HOME);
  1345 
  1346 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1347 use isatool fixseq to adapt your ML programs (this works for fully
  1348 qualified references to the Sequence structure only!);
  1349 
  1350 * use_thy no longer requires writable current directory; it always
  1351 reloads .ML *and* .thy file, if either one is out of date;
  1352 
  1353 
  1354 *** Classical Reasoner ***
  1355 
  1356 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1357 tactics that use classical reasoning to simplify a subgoal without
  1358 splitting it into several subgoals;
  1359 
  1360 * Safe_tac: like safe_tac but uses the default claset;
  1361 
  1362 
  1363 *** Simplifier ***
  1364 
  1365 * added simplification meta rules:
  1366     (asm_)(full_)simplify: simpset -> thm -> thm;
  1367 
  1368 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1369 logics (again);
  1370 
  1371 * added prems argument to simplification procedures;
  1372 
  1373 * HOL, FOL, ZF: added infix function `addsplits':
  1374   instead of `<simpset> setloop (split_tac <thms>)'
  1375   you can simply write `<simpset> addsplits <thms>'
  1376 
  1377 
  1378 *** Syntax ***
  1379 
  1380 * TYPE('a) syntax for type reflection terms;
  1381 
  1382 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1383 
  1384 * pretty printer: changed order of mixfix annotation preference (again!);
  1385 
  1386 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1387 
  1388 
  1389 *** HOL ***
  1390 
  1391 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1392   with `addloop' of the simplifier to faciliate case splitting in premises.
  1393 
  1394 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1395 
  1396 * HOL/Auth: new protocol proofs including some for the Internet
  1397   protocol TLS;
  1398 
  1399 * HOL/Map: new theory of `maps' a la VDM;
  1400 
  1401 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1402 cancelling out common nat summands from =, <, <= (in)equalities, or
  1403 differences; simplification procedures nat_cancel_factor for
  1404 cancelling common factor from =, <, <= (in)equalities over natural
  1405 sums; nat_cancel contains both kinds of procedures, it is installed by
  1406 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1407 
  1408 * HOL/simplifier: terms of the form
  1409   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1410   are rewritten to
  1411   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1412   and those of the form
  1413   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1414   are rewritten to
  1415   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1416 
  1417 * HOL/datatype
  1418   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1419 
  1420   P(t_case f1 ... fn x) =
  1421      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1422         ...
  1423        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1424      )
  1425 
  1426   and a theorem `split_t_case_asm' of the form
  1427 
  1428   P(t_case f1 ... fn x) =
  1429     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1430         ...
  1431        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1432      )
  1433   which can be added to a simpset via `addsplits'. The existing theorems
  1434   expand_list_case and expand_option_case have been renamed to
  1435   split_list_case and split_option_case.
  1436 
  1437 * HOL/Arithmetic:
  1438   - `pred n' is automatically converted to `n-1'.
  1439     Users are strongly encouraged not to use `pred' any longer,
  1440     because it will disappear altogether at some point.
  1441   - Users are strongly encouraged to write "0 < n" rather than
  1442     "n ~= 0". Theorems and proof tools have been modified towards this
  1443     `standard'.
  1444 
  1445 * HOL/Lists:
  1446   the function "set_of_list" has been renamed "set" (and its theorems too);
  1447   the function "nth" now takes its arguments in the reverse order and
  1448   has acquired the infix notation "!" as in "xs!n".
  1449 
  1450 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1451 
  1452 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1453   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1454 
  1455 * HOL/record: extensible records with schematic structural subtyping
  1456 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1457 still lacks various theorems and concrete record syntax;
  1458 
  1459 
  1460 *** HOLCF ***
  1461 
  1462 * removed "axioms" and "generated by" sections;
  1463 
  1464 * replaced "ops" section by extended "consts" section, which is capable of
  1465   handling the continuous function space "->" directly;
  1466 
  1467 * domain package:
  1468   . proves theorems immediately and stores them in the theory,
  1469   . creates hierachical name space,
  1470   . now uses normal mixfix annotations (instead of cinfix...),
  1471   . minor changes to some names and values (for consistency),
  1472   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1473   . separator between mutual domain defs: changed "," to "and",
  1474   . improved handling of sort constraints;  now they have to
  1475     appear on the left-hand side of the equations only;
  1476 
  1477 * fixed LAM <x,y,zs>.b syntax;
  1478 
  1479 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1480 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1481 
  1482 
  1483 *** FOL and ZF ***
  1484 
  1485 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1486   with `addloop' of the simplifier to faciliate case splitting in premises.
  1487 
  1488 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1489 in HOL, they strip ALL and --> from proved theorems;
  1490 
  1491 
  1492 
  1493 New in Isabelle94-8 (May 1997)
  1494 ------------------------------
  1495 
  1496 *** General Changes ***
  1497 
  1498 * new utilities to build / run / maintain Isabelle etc. (in parts
  1499 still somewhat experimental); old Makefiles etc. still functional;
  1500 
  1501 * new 'Isabelle System Manual';
  1502 
  1503 * INSTALL text, together with ./configure and ./build scripts;
  1504 
  1505 * reimplemented type inference for greater efficiency, better error
  1506 messages and clean internal interface;
  1507 
  1508 * prlim command for dealing with lots of subgoals (an easier way of
  1509 setting goals_limit);
  1510 
  1511 
  1512 *** Syntax ***
  1513 
  1514 * supports alternative (named) syntax tables (parser and pretty
  1515 printer); internal interface is provided by add_modesyntax(_i);
  1516 
  1517 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1518 be used in conjunction with the Isabelle symbol font; uses the
  1519 "symbols" syntax table;
  1520 
  1521 * added token_translation interface (may translate name tokens in
  1522 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1523 the current print_mode); IMPORTANT: user print translation functions
  1524 are responsible for marking newly introduced bounds
  1525 (Syntax.mark_boundT);
  1526 
  1527 * token translations for modes "xterm" and "xterm_color" that display
  1528 names in bold, underline etc. or colors (which requires a color
  1529 version of xterm);
  1530 
  1531 * infixes may now be declared with names independent of their syntax;
  1532 
  1533 * added typed_print_translation (like print_translation, but may
  1534 access type of constant);
  1535 
  1536 
  1537 *** Classical Reasoner ***
  1538 
  1539 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1540 some limitations.  Blast_tac...
  1541   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1542   + ignores elimination rules that don't have the correct format
  1543         (the conclusion MUST be a formula variable)
  1544   + ignores types, which can make HOL proofs fail
  1545   + rules must not require higher-order unification, e.g. apply_type in ZF
  1546     [message "Function Var's argument not a bound variable" relates to this]
  1547   + its proof strategy is more general but can actually be slower
  1548 
  1549 * substitution with equality assumptions no longer permutes other
  1550 assumptions;
  1551 
  1552 * minor changes in semantics of addafter (now called addaltern); renamed
  1553 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1554 (and access functions for it);
  1555 
  1556 * improved combination of classical reasoner and simplifier:
  1557   + functions for handling clasimpsets
  1558   + improvement of addss: now the simplifier is called _after_ the
  1559     safe steps.
  1560   + safe variant of addss called addSss: uses safe simplifications
  1561     _during_ the safe steps. It is more complete as it allows multiple
  1562     instantiations of unknowns (e.g. with slow_tac).
  1563 
  1564 *** Simplifier ***
  1565 
  1566 * added interface for simplification procedures (functions that
  1567 produce *proven* rewrite rules on the fly, depending on current
  1568 redex);
  1569 
  1570 * ordering on terms as parameter (used for ordered rewriting);
  1571 
  1572 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1573 
  1574 * the solver is now split into a safe and an unsafe part.
  1575 This should be invisible for the normal user, except that the
  1576 functions setsolver and addsolver have been renamed to setSolver and
  1577 addSolver; added safe_asm_full_simp_tac;
  1578 
  1579 
  1580 *** HOL ***
  1581 
  1582 * a generic induction tactic `induct_tac' which works for all datatypes and
  1583 also for type `nat';
  1584 
  1585 * a generic case distinction tactic `exhaust_tac' which works for all
  1586 datatypes and also for type `nat';
  1587 
  1588 * each datatype comes with a function `size';
  1589 
  1590 * patterns in case expressions allow tuple patterns as arguments to
  1591 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1592 
  1593 * primrec now also works with type nat;
  1594 
  1595 * recdef: a new declaration form, allows general recursive functions to be
  1596 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1597 
  1598 * the constant for negation has been renamed from "not" to "Not" to
  1599 harmonize with FOL, ZF, LK, etc.;
  1600 
  1601 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1602 infinite lists;
  1603 
  1604 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1605 
  1606 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1607 problems in commutative rings, using axiomatic type classes for + and *;
  1608 
  1609 * more examples in HOL/MiniML and HOL/Auth;
  1610 
  1611 * more default rewrite rules for quantifiers, union/intersection;
  1612 
  1613 * a new constant `arbitrary == @x.False';
  1614 
  1615 * HOLCF/IOA replaces old HOL/IOA;
  1616 
  1617 * HOLCF changes: derived all rules and arities
  1618   + axiomatic type classes instead of classes
  1619   + typedef instead of faking type definitions
  1620   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1621   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1622   + eliminated the types void, one, tr
  1623   + use unit lift and bool lift (with translations) instead of one and tr
  1624   + eliminated blift from Lift3.thy (use Def instead of blift)
  1625   all eliminated rules are derived as theorems --> no visible changes ;
  1626 
  1627 
  1628 *** ZF ***
  1629 
  1630 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1631 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1632 as ZF_cs addSIs [equalityI];
  1633 
  1634 
  1635 
  1636 New in Isabelle94-7 (November 96)
  1637 ---------------------------------
  1638 
  1639 * allowing negative levels (as offsets) in prlev and choplev;
  1640 
  1641 * super-linear speedup for large simplifications;
  1642 
  1643 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1644 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1645 FAIL); can suppress it using the command Delsimps (ex_simps @
  1646 all_simps); De Morgan laws are also now included, by default;
  1647 
  1648 * improved printing of ==>  :  ~:
  1649 
  1650 * new object-logic "Sequents" adds linear logic, while replacing LK
  1651 and Modal (thanks to Sara Kalvala);
  1652 
  1653 * HOL/Auth: correctness proofs for authentication protocols;
  1654 
  1655 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1656 examples on HOL/Auth);
  1657 
  1658 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1659 the rewriter and classical reasoner simultaneously;
  1660 
  1661 * function uresult no longer returns theorems in "standard" format;
  1662 regain previous version by: val uresult = standard o uresult;
  1663 
  1664 
  1665 
  1666 New in Isabelle94-6
  1667 -------------------
  1668 
  1669 * oracles -- these establish an interface between Isabelle and trusted
  1670 external reasoners, which may deliver results as theorems;
  1671 
  1672 * proof objects (in particular record all uses of oracles);
  1673 
  1674 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1675 
  1676 * "constdefs" section in theory files;
  1677 
  1678 * "primrec" section (HOL) no longer requires names;
  1679 
  1680 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1681 
  1682 
  1683 
  1684 New in Isabelle94-5
  1685 -------------------
  1686 
  1687 * reduced space requirements;
  1688 
  1689 * automatic HTML generation from theories;
  1690 
  1691 * theory files no longer require "..." (quotes) around most types;
  1692 
  1693 * new examples, including two proofs of the Church-Rosser theorem;
  1694 
  1695 * non-curried (1994) version of HOL is no longer distributed;
  1696 
  1697 
  1698 
  1699 New in Isabelle94-4
  1700 -------------------
  1701 
  1702 * greatly reduced space requirements;
  1703 
  1704 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1705 
  1706 * searchable theorem database (see the section "Retrieving theorems" on
  1707 page 8 of the Reference Manual);
  1708 
  1709 * new examples, including Grabczewski's monumental case study of the
  1710 Axiom of Choice;
  1711 
  1712 * The previous version of HOL renamed to Old_HOL;
  1713 
  1714 * The new version of HOL (previously called CHOL) uses a curried syntax
  1715 for functions.  Application looks like f a b instead of f(a,b);
  1716 
  1717 * Mutually recursive inductive definitions finally work in HOL;
  1718 
  1719 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1720 translates to the operator "split";
  1721 
  1722 
  1723 
  1724 New in Isabelle94-3
  1725 -------------------
  1726 
  1727 * new infix operator, addss, allowing the classical reasoner to
  1728 perform simplification at each step of its search.  Example:
  1729         fast_tac (cs addss ss)
  1730 
  1731 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1732 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1733 look like (a,b) instead of <a,b>;
  1734 
  1735 * PLEASE NOTE: CHOL will eventually replace HOL!
  1736 
  1737 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1738 It translates to the operator "split".  A new theory of integers is available;
  1739 
  1740 * In ZF, integer numerals now denote two's-complement binary integers.
  1741 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1742 
  1743 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1744 of the Axiom of Choice;
  1745 
  1746 
  1747 
  1748 New in Isabelle94-2
  1749 -------------------
  1750 
  1751 * Significantly faster resolution;
  1752 
  1753 * the different sections in a .thy file can now be mixed and repeated
  1754 freely;
  1755 
  1756 * Database of theorems for FOL, HOL and ZF.  New
  1757 commands including qed, qed_goal and bind_thm store theorems in the database.
  1758 
  1759 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1760 a given theory (thms_of), or find out what theory a theorem was proved in
  1761 (theory_of_thm);
  1762 
  1763 * Bugs fixed in the inductive definition and datatype packages;
  1764 
  1765 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1766 and HOL_dup_cs obsolete;
  1767 
  1768 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1769 have been removed;
  1770 
  1771 * Simpler definition of function space in ZF;
  1772 
  1773 * new results about cardinal and ordinal arithmetic in ZF;
  1774 
  1775 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1776 types;
  1777 
  1778 
  1779 $Id$