NEWS
author oheimb
Thu Aug 09 10:16:23 2001 +0200 (2001-08-09)
changeset 11492 6659e1ddd4ca
parent 11487 95071c9e85a3
child 11542 2afde2de26d6
permissions -rw-r--r--
renamed addaltern to addafter, addSaltern to addSafter
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2001 (?? 2001)
     6 -----------------------------
     7 
     8 *** HOL ***
     9 
    10 * HOL: added "The" definite description operator;
    11 
    12 * HOL: made split_all_tac safe. EXISTING PROOFS MAY FAIL OR LOOP, so in this
    13   (rare) case use   delSWrapper "split_all_tac" addSbefore 
    14                     ("unsafe_split_all_tac", unsafe_split_all_tac)
    15 
    16 * HOL: added safe wrapper "split_conv_tac" to claset.  EXISTING PROOFS
    17 MAY FAIL;
    18 
    19 * Classical reasoner: renamed addaltern to addafter, addSaltern to addSafter
    20 
    21 * HOL: introduced f^n = f o ... o f
    22   WARNING: due to the limits of Isabelle's type classes, ^ on functions and
    23   relations has too general a domain, namely ('a * 'b)set and 'a => 'b.
    24   This means that it may be necessary to attach explicit type constraints.
    25 
    26 * HOL: syntax translations now work properly with numerals and records
    27 expressions;
    28 
    29 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
    30 Florian Kammüller;
    31 
    32 
    33 *** ZF ***
    34 
    35 * ZF: the integer library now covers quotients and remainders, with
    36 many laws relating division to addition, multiplication, etc.;
    37 
    38 
    39 *** General ***
    40 
    41 * Classical reasoner: renamed addaltern to addafter, addSaltern to
    42 addSafter;
    43 
    44 * print modes "type_brackets" and "no_type_brackets" control output of
    45 nested => (types); the default behaviour is "brackets";
    46 
    47 
    48 
    49 New in Isabelle99-2 (February 2001)
    50 -----------------------------------
    51 
    52 *** Overview of INCOMPATIBILITIES ***
    53 
    54 * HOL: please note that theories in the Library and elsewhere often use the
    55 new-style (Isar) format; to refer to their theorems in an ML script you must
    56 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
    57 
    58 * HOL: inductive package no longer splits induction rule aggressively,
    59 but only as far as specified by the introductions given; the old
    60 format may be recovered via ML function complete_split_rule or attribute
    61 'split_rule (complete)';
    62 
    63 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
    64 gfp_Tarski to gfp_unfold;
    65 
    66 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
    67 
    68 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
    69 relation); infix "^^" has been renamed "``"; infix "``" has been
    70 renamed "`"; "univalent" has been renamed "single_valued";
    71 
    72 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
    73 operation;
    74 
    75 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
    76 
    77 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
    78 
    79 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
    80 consequence, it is no longer monotonic wrt. the local goal context
    81 (which is now passed through the inductive cases);
    82 
    83 * Document preparation: renamed standard symbols \<ll> to \<lless> and
    84 \<gg> to \<ggreater>;
    85 
    86 
    87 *** Document preparation ***
    88 
    89 * \isabellestyle{NAME} selects version of Isabelle output (currently
    90 available: are "it" for near math-mode best-style output, "sl" for
    91 slanted text style, and "tt" for plain type-writer; if no
    92 \isabellestyle command is given, output is according to slanted
    93 type-writer);
    94 
    95 * support sub/super scripts (for single symbols only), input syntax is
    96 like this: "A\<^sup>*" or "A\<^sup>\<star>";
    97 
    98 * some more standard symbols; see Appendix A of the system manual for
    99 the complete list of symbols defined in isabellesym.sty;
   100 
   101 * improved isabelle style files; more abstract symbol implementation
   102 (should now use \isamath{...} and \isatext{...} in custom symbol
   103 definitions);
   104 
   105 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   106 state; Note that presentation of goal states does not conform to
   107 actual human-readable proof documents.  Please do not include goal
   108 states into document output unless you really know what you are doing!
   109 
   110 * proper indentation of antiquoted output with proportional LaTeX
   111 fonts;
   112 
   113 * no_document ML operator temporarily disables LaTeX document
   114 generation;
   115 
   116 * isatool unsymbolize tunes sources for plain ASCII communication;
   117 
   118 
   119 *** Isar ***
   120 
   121 * Pure: Isar now suffers initial goal statements to contain unbound
   122 schematic variables (this does not conform to actual readable proof
   123 documents, due to unpredictable outcome and non-compositional proof
   124 checking); users who know what they are doing may use schematic goals
   125 for Prolog-style synthesis of proven results;
   126 
   127 * Pure: assumption method (an implicit finishing) now handles actual
   128 rules as well;
   129 
   130 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   131 initial goal, declare "that" only as Pure intro (only for single
   132 steps); the "that" rule assumption may now be involved in implicit
   133 finishing, thus ".." becomes a feasible for trivial obtains;
   134 
   135 * Pure: default proof step now includes 'intro_classes'; thus trivial
   136 instance proofs may be performed by "..";
   137 
   138 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   139 statements as well;
   140 
   141 * Pure: more robust selection of calculational rules;
   142 
   143 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   144 rule (as well as the assumption rule);
   145 
   146 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   147 lemmas, using the graph browser tool;
   148 
   149 * Pure: predict failure of "show" in interactive mode;
   150 
   151 * Pure: 'thms_containing' now takes actual terms as arguments;
   152 
   153 * HOL: improved method 'induct' --- now handles non-atomic goals
   154 (potential INCOMPATIBILITY); tuned error handling;
   155 
   156 * HOL: cases and induct rules now provide explicit hints about the
   157 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   158 any remaining facts are inserted into the goal verbatim;
   159 
   160 * HOL: local contexts (aka cases) may now contain term bindings as
   161 well; the 'cases' and 'induct' methods new provide a ?case binding for
   162 the result to be shown in each case;
   163 
   164 * HOL: added 'recdef_tc' command;
   165 
   166 * isatool convert assists in eliminating legacy ML scripts;
   167 
   168 
   169 *** HOL ***
   170 
   171 * HOL/Library: a collection of generic theories to be used together
   172 with main HOL; the theory loader path already includes this directory
   173 by default; the following existing theories have been moved here:
   174 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   175 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   176 
   177 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   178 modelling and verification task performed in Isabelle/HOL +
   179 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   180 
   181 * HOL/Algebra: special summation operator SUM no longer exists, it has
   182 been replaced by setsum; infix 'assoc' now has priority 50 (like
   183 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   184 'domain', this makes the theory consistent with mathematical
   185 literature;
   186 
   187 * HOL basics: added overloaded operations "inverse" and "divide"
   188 (infix "/"), syntax for generic "abs" operation, generic summation
   189 operator \<Sum>;
   190 
   191 * HOL/typedef: simplified package, provide more useful rules (see also
   192 HOL/subset.thy);
   193 
   194 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   195 now expressed as a proper nested rule (old-style tactic scripts may
   196 require atomize_strip_tac to cope with non-atomic premises);
   197 
   198 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   199 to "split_conv" (old name still available for compatibility);
   200 
   201 * HOL: improved concrete syntax for strings (e.g. allows translation
   202 rules with string literals);
   203 
   204 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   205 and Fleuriot's mechanization of analysis;
   206 
   207 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   208 
   209 
   210 *** CTT ***
   211 
   212 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   213 "lam" is displayed as TWO lambda-symbols
   214 
   215 * CTT: theory Main now available, containing everything (that is, Bool
   216 and Arith);
   217 
   218 
   219 *** General ***
   220 
   221 * Pure: the Simplifier has been implemented properly as a derived rule
   222 outside of the actual kernel (at last!); the overall performance
   223 penalty in practical applications is about 50%, while reliability of
   224 the Isabelle inference kernel has been greatly improved;
   225 
   226 * print modes "brackets" and "no_brackets" control output of nested =>
   227 (types) and ==> (props); the default behaviour is "brackets";
   228 
   229 * Provers: fast_tac (and friends) now handle actual object-logic rules
   230 as assumptions as well;
   231 
   232 * system: support Poly/ML 4.0;
   233 
   234 * system: isatool install handles KDE version 1 or 2;
   235 
   236 
   237 
   238 New in Isabelle99-1 (October 2000)
   239 ----------------------------------
   240 
   241 *** Overview of INCOMPATIBILITIES ***
   242 
   243 * HOL: simplification of natural numbers is much changed; to partly
   244 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   245 issue the following ML commands:
   246 
   247   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   248   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   249 
   250 * HOL: simplification no longer dives into case-expressions; this is
   251 controlled by "t.weak_case_cong" for each datatype t;
   252 
   253 * HOL: nat_less_induct renamed to less_induct;
   254 
   255 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   256 fixsome to patch .thy and .ML sources automatically;
   257 
   258   select_equality  -> some_equality
   259   select_eq_Ex     -> some_eq_ex
   260   selectI2EX       -> someI2_ex
   261   selectI2         -> someI2
   262   selectI          -> someI
   263   select1_equality -> some1_equality
   264   Eps_sym_eq       -> some_sym_eq_trivial
   265   Eps_eq           -> some_eq_trivial
   266 
   267 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   268 
   269 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   270 instead);
   271 
   272 * HOL: the recursion equations generated by 'recdef' are now called
   273 f.simps instead of f.rules;
   274 
   275 * HOL: qed_spec_mp now also handles bounded ALL as well;
   276 
   277 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   278 sometimes be needed;
   279 
   280 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   281 
   282 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   283 
   284 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   285 product is now "<*>" instead of "Times"; the lexicographic product is
   286 now "<*lex*>" instead of "**";
   287 
   288 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   289 of main HOL, but was unused); better use HOL's datatype package;
   290 
   291 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   292 the old syntax may be recovered as follows:
   293 
   294   syntax (symbols)
   295     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   296       (infixl "\\<oplus>" 100)
   297 
   298 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   299 
   300 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   301 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   302 internally;
   303 
   304 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   305 changed from A/r to A//r;
   306 
   307 * ZF: new treatment of arithmetic (nat & int) may break some old
   308 proofs;
   309 
   310 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   311 rulify -> rule_format, elimify -> elim_format, ...);
   312 
   313 * Isar/Provers: intro/elim/dest attributes changed; renamed
   314 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   315 should have to change intro!! to intro? only); replaced "delrule" by
   316 "rule del";
   317 
   318 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   319 
   320 * Provers: strengthened force_tac by using new first_best_tac;
   321 
   322 * LaTeX document preparation: several changes of isabelle.sty (see
   323 lib/texinputs);
   324 
   325 
   326 *** Document preparation ***
   327 
   328 * formal comments (text blocks etc.) in new-style theories may now
   329 contain antiquotations of thm/prop/term/typ/text to be presented
   330 according to latex print mode; concrete syntax is like this:
   331 @{term[show_types] "f(x) = a + x"};
   332 
   333 * isatool mkdir provides easy setup of Isabelle session directories,
   334 including proper document sources;
   335 
   336 * generated LaTeX sources are now deleted after successful run
   337 (isatool document -c); may retain a copy somewhere else via -D option
   338 of isatool usedir;
   339 
   340 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   341 style files, achieving self-contained LaTeX sources and simplifying
   342 LaTeX debugging;
   343 
   344 * old-style theories now produce (crude) LaTeX output as well;
   345 
   346 * browser info session directories are now self-contained (may be put
   347 on WWW server seperately); improved graphs of nested sessions; removed
   348 graph for 'all sessions';
   349 
   350 * several improvements in isabelle style files; \isabellestyle{it}
   351 produces fake math mode output; \isamarkupheader is now \section by
   352 default; see lib/texinputs/isabelle.sty etc.;
   353 
   354 
   355 *** Isar ***
   356 
   357 * Isar/Pure: local results and corresponding term bindings are now
   358 subject to Hindley-Milner polymorphism (similar to ML); this
   359 accommodates incremental type-inference very nicely;
   360 
   361 * Isar/Pure: new derived language element 'obtain' supports
   362 generalized existence reasoning;
   363 
   364 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   365 support accumulation of results, without applying any rules yet;
   366 useful to collect intermediate results without explicit name
   367 references, and for use with transitivity rules with more than 2
   368 premises;
   369 
   370 * Isar/Pure: scalable support for case-analysis type proofs: new
   371 'case' language element refers to local contexts symbolically, as
   372 produced by certain proof methods; internally, case names are attached
   373 to theorems as "tags";
   374 
   375 * Isar/Pure: theory command 'hide' removes declarations from
   376 class/type/const name spaces;
   377 
   378 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   379 indicate potential overloading;
   380 
   381 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   382 
   383 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   384 "{a,b,c}" instead of {a,b,c};
   385 
   386 * Isar/Pure now provides its own version of intro/elim/dest
   387 attributes; useful for building new logics, but beware of confusion
   388 with the version in Provers/classical;
   389 
   390 * Isar/Pure: the local context of (non-atomic) goals is provided via
   391 case name 'antecedent';
   392 
   393 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   394 to the current context is now done automatically);
   395 
   396 * Isar/Pure: theory command 'method_setup' provides a simple interface
   397 for definining proof methods in ML;
   398 
   399 * Isar/Provers: intro/elim/dest attributes changed; renamed
   400 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   401 most cases, one should have to change intro!! to intro? only);
   402 replaced "delrule" by "rule del";
   403 
   404 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   405 'symmetric' attribute (the latter supercedes [RS sym]);
   406 
   407 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   408 method modifier); 'simp' method: 'only:' modifier removes loopers as
   409 well (including splits);
   410 
   411 * Isar/Provers: Simplifier and Classical methods now support all kind
   412 of modifiers used in the past, including 'cong', 'iff', etc.
   413 
   414 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   415 of Simplifier and Classical reasoner);
   416 
   417 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   418 now support named cases; major packages (inductive, datatype, primrec,
   419 recdef) support case names and properly name parameters;
   420 
   421 * Isar/HOL: new transitivity rules for substitution in inequalities --
   422 monotonicity conditions are extracted to be proven at end of
   423 calculations;
   424 
   425 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   426 method anyway;
   427 
   428 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   429 split_if split_if_asm; datatype package provides theorems foo.splits =
   430 foo.split foo.split_asm for each datatype;
   431 
   432 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   433 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   434 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   435 use "(cases (simplified))" method in proper proof texts);
   436 
   437 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   438 
   439 * Isar: names of theorems etc. may be natural numbers as well;
   440 
   441 * Isar: 'pr' command: optional arguments for goals_limit and
   442 ProofContext.prems_limit; no longer prints theory contexts, but only
   443 proof states;
   444 
   445 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   446 additional print modes to be specified; e.g. "pr(latex)" will print
   447 proof state according to the Isabelle LaTeX style;
   448 
   449 * Isar: improved support for emulating tactic scripts, including proof
   450 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   451 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   452 (for HOL datatypes);
   453 
   454 * Isar: simplified (more robust) goal selection of proof methods: 1st
   455 goal, all goals, or explicit goal specifier (tactic emulation); thus
   456 'proof method scripts' have to be in depth-first order;
   457 
   458 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   459 
   460 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   461 should instead use individual commands for printing items
   462 (print_commands, print_methods etc.);
   463 
   464 * Isar: added 'nothing' --- the empty list of theorems;
   465 
   466 
   467 *** HOL ***
   468 
   469 * HOL/MicroJava: formalization of a fragment of Java, together with a
   470 corresponding virtual machine and a specification of its bytecode
   471 verifier and a lightweight bytecode verifier, including proofs of
   472 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   473 Cornelia Pusch (see also the homepage of project Bali at
   474 http://isabelle.in.tum.de/Bali/);
   475 
   476 * HOL/Algebra: new theory of rings and univariate polynomials, by
   477 Clemens Ballarin;
   478 
   479 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   480 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   481 Rasmussen;
   482 
   483 * HOL/Lattice: fundamental concepts of lattice theory and order
   484 structures, including duals, properties of bounds versus algebraic
   485 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   486 Theorem for complete lattices etc.; may also serve as a demonstration
   487 for abstract algebraic reasoning using axiomatic type classes, and
   488 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   489 
   490 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   491 von Oheimb;
   492 
   493 * HOL/IMPP: extension of IMP with local variables and mutually
   494 recursive procedures, by David von Oheimb;
   495 
   496 * HOL/Lambda: converted into new-style theory and document;
   497 
   498 * HOL/ex/Multiquote: example of multiple nested quotations and
   499 anti-quotations -- basically a generalized version of de-Bruijn
   500 representation; very useful in avoiding lifting of operations;
   501 
   502 * HOL/record: added general record equality rule to simpset; fixed
   503 select-update simplification procedure to handle extended records as
   504 well; admit "r" as field name;
   505 
   506 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   507 other numeric types and also as the identity of groups, rings, etc.;
   508 
   509 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   510 Types nat and int belong to this axclass;
   511 
   512 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   513    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   514    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   515   two terms #m*u and #n*u are replaced by #(m+n)*u
   516     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   517   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   518     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   519 
   520 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   521 powerful prover for predicate logic but knows nothing of clasets; see
   522 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   523 
   524 * HOL: new version of "case_tac" subsumes both boolean case split and
   525 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   526 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   527 
   528 * HOL: simplification no longer dives into case-expressions: only the
   529 selector expression is simplified, but not the remaining arms; to
   530 enable full simplification of case-expressions for datatype t, you may
   531 remove t.weak_case_cong from the simpset, either globally (Delcongs
   532 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   533 
   534 * HOL/recdef: the recursion equations generated by 'recdef' for
   535 function 'f' are now called f.simps instead of f.rules; if all
   536 termination conditions are proved automatically, these simplification
   537 rules are added to the simpset, as in primrec; rules may be named
   538 individually as well, resulting in a separate list of theorems for
   539 each equation;
   540 
   541 * HOL/While is a new theory that provides a while-combinator. It
   542 permits the definition of tail-recursive functions without the
   543 provision of a termination measure. The latter is necessary once the
   544 invariant proof rule for while is applied.
   545 
   546 * HOL: new (overloaded) notation for the set of elements below/above
   547 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   548 
   549 * HOL: theorems impI, allI, ballI bound as "strip";
   550 
   551 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   552 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   553 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   554 
   555 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   556 
   557 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   558 main HOL, but was unused);
   559 
   560 * HOL: fewer consts declared as global (e.g. have to refer to
   561 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   562 
   563 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   564 in case of overlap with user translations (e.g. judgements over
   565 tuples); (note that the underlying logical represenation is still
   566 bogus);
   567 
   568 
   569 *** ZF ***
   570 
   571 * ZF: simplification automatically cancels common terms in arithmetic
   572 expressions over nat and int;
   573 
   574 * ZF: new treatment of nat to minimize type-checking: all operators
   575 coerce their operands to a natural number using the function natify,
   576 making the algebraic laws unconditional;
   577 
   578 * ZF: as above, for int: operators coerce their operands to an integer
   579 using the function intify;
   580 
   581 * ZF: the integer library now contains many of the usual laws for the
   582 orderings, including $<=, and monotonicity laws for $+ and $*;
   583 
   584 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   585 simplification;
   586 
   587 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   588 to the simplifier and classical reasoner simultaneously;
   589 
   590 
   591 *** General ***
   592 
   593 * Provers: blast_tac now handles actual object-logic rules as
   594 assumptions; note that auto_tac uses blast_tac internally as well;
   595 
   596 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   597 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   598 
   599 * Provers: delrules now handles destruct rules as well (no longer need
   600 explicit make_elim);
   601 
   602 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   603   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   604 use instead the strong form,
   605   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   606 in HOL, FOL and ZF the function cla_make_elim will create such rules
   607 from destruct-rules;
   608 
   609 * Provers: Simplifier.easy_setup provides a fast path to basic
   610 Simplifier setup for new object-logics;
   611 
   612 * Pure: AST translation rules no longer require constant head on LHS;
   613 
   614 * Pure: improved name spaces: ambiguous output is qualified; support
   615 for hiding of names;
   616 
   617 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   618 XSYMBOL_HOME; no longer need to do manual configuration in most
   619 situations;
   620 
   621 * system: compression of ML heaps images may now be controlled via -c
   622 option of isabelle and isatool usedir (currently only observed by
   623 Poly/ML);
   624 
   625 * system: isatool installfonts may handle X-Symbol fonts as well (very
   626 useful for remote X11);
   627 
   628 * system: provide TAGS file for Isabelle sources;
   629 
   630 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   631 order;
   632 
   633 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   634 timing flag supersedes proof_timing and Toplevel.trace;
   635 
   636 * ML: new combinators |>> and |>>> for incremental transformations
   637 with secondary results (e.g. certain theory extensions):
   638 
   639 * ML: PureThy.add_defs gets additional argument to indicate potential
   640 overloading (usually false);
   641 
   642 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   643 results;
   644 
   645 
   646 
   647 New in Isabelle99 (October 1999)
   648 --------------------------------
   649 
   650 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   651 
   652 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   653 are no longer simplified.  (This allows the simplifier to unfold recursive
   654 functional programs.)  To restore the old behaviour, declare
   655 
   656     Delcongs [if_weak_cong];
   657 
   658 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   659 complement;
   660 
   661 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   662 
   663 * HOL/datatype: mutual_induct_tac no longer exists --
   664   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   665 
   666 * HOL/typedef: fixed type inference for representing set; type
   667 arguments now have to occur explicitly on the rhs as type constraints;
   668 
   669 * ZF: The con_defs part of an inductive definition may no longer refer
   670 to constants declared in the same theory;
   671 
   672 * HOL, ZF: the function mk_cases, generated by the inductive
   673 definition package, has lost an argument.  To simplify its result, it
   674 uses the default simpset instead of a supplied list of theorems.
   675 
   676 * HOL/List: the constructors of type list are now Nil and Cons;
   677 
   678 * Simplifier: the type of the infix ML functions
   679         setSSolver addSSolver setSolver addSolver
   680 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   681 for packaging solvers. A solver is created via
   682         mk_solver: string -> (thm list -> int -> tactic) -> solver
   683 where the string argument is only a comment.
   684 
   685 
   686 *** Proof tools ***
   687 
   688 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   689 decision procedure for linear arithmetic. Currently it is used for
   690 types `nat', `int', and `real' in HOL (see below); it can, should and
   691 will be instantiated for other types and logics as well.
   692 
   693 * The simplifier now accepts rewrite rules with flexible heads, eg
   694      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   695   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   696   matching.
   697 
   698 
   699 *** General ***
   700 
   701 * New Isabelle/Isar subsystem provides an alternative to traditional
   702 tactical theorem proving; together with the ProofGeneral/isar user
   703 interface it offers an interactive environment for developing human
   704 readable proof documents (Isar == Intelligible semi-automated
   705 reasoning); for further information see isatool doc isar-ref,
   706 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   707 
   708 * improved and simplified presentation of theories: better HTML markup
   709 (including colors), graph views in several sizes; isatool usedir now
   710 provides a proper interface for user theories (via -P option); actual
   711 document preparation based on (PDF)LaTeX is available as well (for
   712 new-style theories only); see isatool doc system for more information;
   713 
   714 * native support for Proof General, both for classic Isabelle and
   715 Isabelle/Isar;
   716 
   717 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   718 using the graph browser tool;
   719 
   720 * Isabelle manuals now also available as PDF;
   721 
   722 * theory loader rewritten from scratch (may not be fully
   723 bug-compatible); old loadpath variable has been replaced by show_path,
   724 add_path, del_path, reset_path functions; new operations such as
   725 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   726 isatool doc ref);
   727 
   728 * improved isatool install: option -k creates KDE application icon,
   729 option -p DIR installs standalone binaries;
   730 
   731 * added ML_PLATFORM setting (useful for cross-platform installations);
   732 more robust handling of platform specific ML images for SML/NJ;
   733 
   734 * the settings environment is now statically scoped, i.e. it is never
   735 created again in sub-processes invoked from isabelle, isatool, or
   736 Isabelle;
   737 
   738 * path element specification '~~' refers to '$ISABELLE_HOME';
   739 
   740 * in locales, the "assumes" and "defines" parts may be omitted if
   741 empty;
   742 
   743 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   744 long arrows);
   745 
   746 * new print_mode "HTML";
   747 
   748 * new flag show_tags controls display of tags of theorems (which are
   749 basically just comments that may be attached by some tools);
   750 
   751 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   752 mode and goal output format:
   753 
   754 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   755 244c244
   756 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   757 ---
   758 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   759 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   760 181c181
   761 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   762 ---
   763 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   764 
   765 * function bind_thms stores lists of theorems (cf. bind_thm);
   766 
   767 * new shorthand tactics ftac, eatac, datac, fatac;
   768 
   769 * qed (and friends) now accept "" as result name; in that case the
   770 theorem is not stored, but proper checks and presentation of the
   771 result still apply;
   772 
   773 * theorem database now also indexes constants "Trueprop", "all",
   774 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   775 
   776 
   777 *** HOL ***
   778 
   779 ** HOL arithmetic **
   780 
   781 * There are now decision procedures for linear arithmetic over nat and
   782 int:
   783 
   784 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   785 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   786 are treated as atomic; subformulae not involving type `nat' or `int'
   787 are ignored; quantified subformulae are ignored unless they are
   788 positive universal or negative existential. The tactic has to be
   789 invoked by hand and can be a little bit slow. In particular, the
   790 running time is exponential in the number of occurrences of `min' and
   791 `max', and `-' on `nat'.
   792 
   793 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   794 (negated) (in)equalities among the premises and the conclusion into
   795 account (i.e. no compound formulae) and does not know about `min' and
   796 `max', and `-' on `nat'. It is fast and is used automatically by the
   797 simplifier.
   798 
   799 NB: At the moment, these decision procedures do not cope with mixed
   800 nat/int formulae where the two parts interact, such as `m < n ==>
   801 int(m) < int(n)'.
   802 
   803 * HOL/Numeral provides a generic theory of numerals (encoded
   804 efficiently as bit strings); setup for types nat/int/real is in place;
   805 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   806 int, existing theories and proof scripts may require a few additional
   807 type constraints;
   808 
   809 * integer division and remainder can now be performed on constant
   810 arguments;
   811 
   812 * many properties of integer multiplication, division and remainder
   813 are now available;
   814 
   815 * An interface to the Stanford Validity Checker (SVC) is available through the
   816 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   817 are proved automatically.  SVC must be installed separately, and its results
   818 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   819 invocation of the underlying oracle).  For SVC see
   820   http://verify.stanford.edu/SVC
   821 
   822 * IsaMakefile: the HOL-Real target now builds an actual image;
   823 
   824 
   825 ** HOL misc **
   826 
   827 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   828 (in Isabelle/Isar) -- by Gertrud Bauer;
   829 
   830 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   831 analysis for assembly languages with subtypes;
   832 
   833 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   834 -- avoids syntactic ambiguities and treats state, transition, and
   835 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   836 changed syntax and (many) tactics;
   837 
   838 * HOL/inductive: Now also handles more general introduction rules such
   839   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   840   theorems are now maintained within the theory (maintained via the
   841   "mono" attribute);
   842 
   843 * HOL/datatype: Now also handles arbitrarily branching datatypes
   844   (using function types) such as
   845 
   846   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   847 
   848 * HOL/record: record_simproc (part of the default simpset) takes care
   849 of selectors applied to updated records; record_split_tac is no longer
   850 part of the default claset; update_defs may now be removed from the
   851 simpset in many cases; COMPATIBILITY: old behavior achieved by
   852 
   853   claset_ref () := claset() addSWrapper record_split_wrapper;
   854   Delsimprocs [record_simproc]
   855 
   856 * HOL/typedef: fixed type inference for representing set; type
   857 arguments now have to occur explicitly on the rhs as type constraints;
   858 
   859 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   860 names rather than an ML expression;
   861 
   862 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   863 supplied later.  Program schemes can be defined, such as
   864     "While B C s = (if B s then While B C (C s) else s)"
   865 where the well-founded relation can be chosen after B and C have been given.
   866 
   867 * HOL/List: the constructors of type list are now Nil and Cons;
   868 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   869 course, ML tools referring to List.list.op # etc. have to be adapted;
   870 
   871 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   872 disabled by default; run isabelle with option -m HOL to get back to
   873 the original Gordon/HOL-style output;
   874 
   875 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   876 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   877 
   878 * HOL basic syntax simplified (more orthogonal): all variants of
   879 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   880 Eps operator is provided as well: "SOME x. P[x]";
   881 
   882 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   883 
   884 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   885 thus available for user theories;
   886 
   887 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   888 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   889 time;
   890 
   891 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   892 several times and then mp;
   893 
   894 
   895 *** LK ***
   896 
   897 * the notation <<...>> is now available as a notation for sequences of
   898 formulas;
   899 
   900 * the simplifier is now installed
   901 
   902 * the axiom system has been generalized (thanks to Soren Heilmann)
   903 
   904 * the classical reasoner now has a default rule database
   905 
   906 
   907 *** ZF ***
   908 
   909 * new primrec section allows primitive recursive functions to be given
   910 directly (as in HOL) over datatypes and the natural numbers;
   911 
   912 * new tactics induct_tac and exhaust_tac for induction (or case
   913 analysis) over datatypes and the natural numbers;
   914 
   915 * the datatype declaration of type T now defines the recursor T_rec;
   916 
   917 * simplification automatically does freeness reasoning for datatype
   918 constructors;
   919 
   920 * automatic type-inference, with AddTCs command to insert new
   921 type-checking rules;
   922 
   923 * datatype introduction rules are now added as Safe Introduction rules
   924 to the claset;
   925 
   926 * the syntax "if P then x else y" is now available in addition to
   927 if(P,x,y);
   928 
   929 
   930 *** Internal programming interfaces ***
   931 
   932 * tuned simplifier trace output; new flag debug_simp;
   933 
   934 * structures Vartab / Termtab (instances of TableFun) offer efficient
   935 tables indexed by indexname_ord / term_ord (compatible with aconv);
   936 
   937 * AxClass.axclass_tac lost the theory argument;
   938 
   939 * tuned current_goals_markers semantics: begin / end goal avoids
   940 printing empty lines;
   941 
   942 * removed prs and prs_fn hook, which was broken because it did not
   943 include \n in its semantics, forcing writeln to add one
   944 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   945 string -> unit if you really want to output text without newline;
   946 
   947 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   948 plain output, interface builders may have to enable 'isabelle_font'
   949 mode to get Isabelle font glyphs as before;
   950 
   951 * refined token_translation interface; INCOMPATIBILITY: output length
   952 now of type real instead of int;
   953 
   954 * theory loader actions may be traced via new ThyInfo.add_hook
   955 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   956 your own database of information attached to *whole* theories -- as
   957 opposed to intra-theory data slots offered via TheoryDataFun;
   958 
   959 * proper handling of dangling sort hypotheses (at last!);
   960 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   961 extra sort hypotheses that can be witnessed from the type signature;
   962 the force_strip_shyps flag is gone, any remaining shyps are simply
   963 left in the theorem (with a warning issued by strip_shyps_warning);
   964 
   965 
   966 
   967 New in Isabelle98-1 (October 1998)
   968 ----------------------------------
   969 
   970 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   971 
   972 * several changes of automated proof tools;
   973 
   974 * HOL: major changes to the inductive and datatype packages, including
   975 some minor incompatibilities of theory syntax;
   976 
   977 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   978 called `inj_on';
   979 
   980 * HOL: removed duplicate thms in Arith:
   981   less_imp_add_less  should be replaced by  trans_less_add1
   982   le_imp_add_le      should be replaced by  trans_le_add1
   983 
   984 * HOL: unary minus is now overloaded (new type constraints may be
   985 required);
   986 
   987 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   988 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   989 now taken as an integer constant.
   990 
   991 * Pure: ML function 'theory_of' renamed to 'theory';
   992 
   993 
   994 *** Proof tools ***
   995 
   996 * Simplifier:
   997   1. Asm_full_simp_tac is now more aggressive.
   998      1. It will sometimes reorient premises if that increases their power to
   999         simplify.
  1000      2. It does no longer proceed strictly from left to right but may also
  1001         rotate premises to achieve further simplification.
  1002      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1003      old Asm_full_simp_tac in that it does not rotate premises.
  1004   2. The simplifier now knows a little bit about nat-arithmetic.
  1005 
  1006 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1007 allows for selected deletion of wrappers, by introduction of names for
  1008 wrapper functionals.  This implies that addbefore, addSbefore,
  1009 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1010 and that adding two tactics with the same name overwrites the first
  1011 one (emitting a warning).
  1012   type wrapper = (int -> tactic) -> (int -> tactic)
  1013   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1014   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1015   delWrapper, delSWrapper: claset *  string            -> claset
  1016   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1017 
  1018 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1019 semantics; addbefore now affects only the unsafe part of step_tac
  1020 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1021 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1022 by Force_tac;
  1023 
  1024 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1025 compWrapper; added safe wrapper (and access functions for it);
  1026 
  1027 * HOL/split_all_tac is now much faster and fails if there is nothing
  1028 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1029 and the names of the automatically generated variables have changed.
  1030 split_all_tac has moved within claset() from unsafe wrappers to safe
  1031 wrappers, which means that !!-bound variables are split much more
  1032 aggressively, and safe_tac and clarify_tac now split such variables.
  1033 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1034 Note: the same holds for record_split_tac, which does the job of
  1035 split_all_tac for record fields.
  1036 
  1037 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1038 permanently to the default simpset using Addsplits just like
  1039 Addsimps. They can be removed via Delsplits just like
  1040 Delsimps. Lower-case versions are also available.
  1041 
  1042 * HOL/Simplifier: The rule split_if is now part of the default
  1043 simpset. This means that the simplifier will eliminate all occurrences
  1044 of if-then-else in the conclusion of a goal. To prevent this, you can
  1045 either remove split_if completely from the default simpset by
  1046 `Delsplits [split_if]' or remove it in a specific call of the
  1047 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1048 other case splitting rules to/from the default simpset: every datatype
  1049 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1050 t is the name of the datatype).
  1051 
  1052 * Classical reasoner / Simplifier combination: new force_tac (and
  1053 derivatives Force_tac, force) combines rewriting and classical
  1054 reasoning (and whatever other tools) similarly to auto_tac, but is
  1055 aimed to solve the given subgoal completely.
  1056 
  1057 
  1058 *** General ***
  1059 
  1060 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1061 and `goalw': the theory is no longer needed as an explicit argument -
  1062 the current theory context is used; assumptions are no longer returned
  1063 at the ML-level unless one of them starts with ==> or !!; it is
  1064 recommended to convert to these new commands using isatool fixgoal
  1065 (backup your sources first!);
  1066 
  1067 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1068 the current theory context, and 'theory' to lookup stored theories;
  1069 
  1070 * new theory section 'locale' for declaring constants, assumptions and
  1071 definitions that have local scope;
  1072 
  1073 * new theory section 'nonterminals' for purely syntactic types;
  1074 
  1075 * new theory section 'setup' for generic ML setup functions
  1076 (e.g. package initialization);
  1077 
  1078 * the distribution now includes Isabelle icons: see
  1079 lib/logo/isabelle-{small,tiny}.xpm;
  1080 
  1081 * isatool install - install binaries with absolute references to
  1082 ISABELLE_HOME/bin;
  1083 
  1084 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1085 
  1086 * print mode 'emacs' reserved for Isamode;
  1087 
  1088 * support multiple print (ast) translations per constant name;
  1089 
  1090 * theorems involving oracles are now printed with a suffixed [!];
  1091 
  1092 
  1093 *** HOL ***
  1094 
  1095 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1096 
  1097 * HOL/inductive package reorganized and improved: now supports mutual
  1098 definitions such as
  1099 
  1100   inductive EVEN ODD
  1101     intrs
  1102       null "0 : EVEN"
  1103       oddI "n : EVEN ==> Suc n : ODD"
  1104       evenI "n : ODD ==> Suc n : EVEN"
  1105 
  1106 new theorem list "elims" contains an elimination rule for each of the
  1107 recursive sets; inductive definitions now handle disjunctive premises
  1108 correctly (also ZF);
  1109 
  1110 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1111 "mutual_induct" no longer exists - the induction rule is always
  1112 contained in "induct";
  1113 
  1114 
  1115 * HOL/datatype package re-implemented and greatly improved: now
  1116 supports mutually recursive datatypes such as
  1117 
  1118   datatype
  1119     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1120             | SUM ('a aexp) ('a aexp)
  1121             | DIFF ('a aexp) ('a aexp)
  1122             | NUM 'a
  1123   and
  1124     'a bexp = LESS ('a aexp) ('a aexp)
  1125             | AND ('a bexp) ('a bexp)
  1126             | OR ('a bexp) ('a bexp)
  1127 
  1128 as well as indirectly recursive datatypes such as
  1129 
  1130   datatype
  1131     ('a, 'b) term = Var 'a
  1132                   | App 'b ((('a, 'b) term) list)
  1133 
  1134 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1135 induction on mutually / indirectly recursive datatypes.
  1136 
  1137 Primrec equations are now stored in theory and can be accessed via
  1138 <function_name>.simps.
  1139 
  1140 INCOMPATIBILITIES:
  1141 
  1142   - Theories using datatypes must now have theory Datatype as an
  1143     ancestor.
  1144   - The specific <typename>.induct_tac no longer exists - use the
  1145     generic induct_tac instead.
  1146   - natE has been renamed to nat.exhaust - use exhaust_tac
  1147     instead of res_inst_tac ... natE. Note that the variable
  1148     names in nat.exhaust differ from the names in natE, this
  1149     may cause some "fragile" proofs to fail.
  1150   - The theorems split_<typename>_case and split_<typename>_case_asm
  1151     have been renamed to <typename>.split and <typename>.split_asm.
  1152   - Since default sorts of type variables are now handled correctly,
  1153     some datatype definitions may have to be annotated with explicit
  1154     sort constraints.
  1155   - Primrec definitions no longer require function name and type
  1156     of recursive argument.
  1157 
  1158 Consider using isatool fixdatatype to adapt your theories and proof
  1159 scripts to the new package (backup your sources first!).
  1160 
  1161 
  1162 * HOL/record package: considerably improved implementation; now
  1163 includes concrete syntax for record types, terms, updates; theorems
  1164 for surjective pairing and splitting !!-bound record variables; proof
  1165 support is as follows:
  1166 
  1167   1) standard conversions (selectors or updates applied to record
  1168 constructor terms) are part of the standard simpset;
  1169 
  1170   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1171 made part of standard simpset and claset via addIffs;
  1172 
  1173   3) a tactic for record field splitting (record_split_tac) is part of
  1174 the standard claset (addSWrapper);
  1175 
  1176 To get a better idea about these rules you may retrieve them via
  1177 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1178 the name of your record type.
  1179 
  1180 The split tactic 3) conceptually simplifies by the following rule:
  1181 
  1182   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1183 
  1184 Thus any record variable that is bound by meta-all will automatically
  1185 blow up into some record constructor term, consequently the
  1186 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1187 solve record problems automatically.
  1188 
  1189 
  1190 * reorganized the main HOL image: HOL/Integ and String loaded by
  1191 default; theory Main includes everything;
  1192 
  1193 * automatic simplification of integer sums and comparisons, using cancellation;
  1194 
  1195 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1196 
  1197 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1198 
  1199 * many new identities for unions, intersections, set difference, etc.;
  1200 
  1201 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1202 called split_if, split_split, split_sum_case and split_nat_case (to go
  1203 with add/delsplits);
  1204 
  1205 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1206 (?x::unit) = (); this is made part of the default simpset, which COULD
  1207 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1208 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1209 unit_abs_eta_conv is added in order to counter the effect of
  1210 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1211 %u.f();
  1212 
  1213 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1214 makes more sense);
  1215 
  1216 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1217   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1218   disjointness reasoning but breaking a few old proofs.
  1219 
  1220 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1221 to 'converse' from 'inverse' (for compatibility with ZF and some
  1222 literature);
  1223 
  1224 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1225 the well-founded relation;
  1226 
  1227 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1228     Compl A.  The "Compl" syntax remains available as input syntax for this
  1229     release ONLY.
  1230 
  1231 * HOL/Update: new theory of function updates:
  1232     f(a:=b) == %x. if x=a then b else f x
  1233 may also be iterated as in f(a:=b,c:=d,...);
  1234 
  1235 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1236 
  1237 * HOL/List:
  1238   - new function list_update written xs[i:=v] that updates the i-th
  1239     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1240   - new function `upt' written [i..j(] which generates the list
  1241     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1242     bound write [i..j], which is a shorthand for [i..j+1(].
  1243   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1244 
  1245 * HOL/Arith:
  1246   - removed 'pred' (predecessor) function;
  1247   - generalized some theorems about n-1;
  1248   - many new laws about "div" and "mod";
  1249   - new laws about greatest common divisors (see theory ex/Primes);
  1250 
  1251 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1252 instead of "inverse";
  1253 
  1254 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1255   of the multiset ordering;
  1256 
  1257 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1258   (not included by default);
  1259 
  1260 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1261 
  1262 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1263   programs, i.e. different program variables may have different types.
  1264 
  1265 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1266   [previously, this check worked only if the rewrite rule was unconditional]
  1267   Now rew can involve either definitions or equalities (either == or =).
  1268 
  1269 
  1270 *** ZF ***
  1271 
  1272 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1273   only the theorems proved on ZF.ML;
  1274 
  1275 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1276   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1277   disjointness reasoning but breaking a few old proofs.
  1278 
  1279 * ZF/Update: new theory of function updates
  1280     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1281   may also be iterated as in f(a:=b,c:=d,...);
  1282 
  1283 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1284 
  1285 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1286   [previously, this check worked only if the rewrite rule was unconditional]
  1287   Now rew can involve either definitions or equalities (either == or =).
  1288 
  1289 * case_tac provided for compatibility with HOL
  1290     (like the old excluded_middle_tac, but with subgoals swapped)
  1291 
  1292 
  1293 *** Internal programming interfaces ***
  1294 
  1295 * Pure: several new basic modules made available for general use, see
  1296 also src/Pure/README;
  1297 
  1298 * improved the theory data mechanism to support encapsulation (data
  1299 kind name replaced by private Object.kind, acting as authorization
  1300 key); new type-safe user interface via functor TheoryDataFun; generic
  1301 print_data function becomes basically useless;
  1302 
  1303 * removed global_names compatibility flag -- all theory declarations
  1304 are qualified by default;
  1305 
  1306 * module Pure/Syntax now offers quote / antiquote translation
  1307 functions (useful for Hoare logic etc. with implicit dependencies);
  1308 see HOL/ex/Antiquote for an example use;
  1309 
  1310 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1311 cterm -> thm;
  1312 
  1313 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1314 subgoal;
  1315 
  1316 * Display.print_goals function moved to Locale.print_goals;
  1317 
  1318 * standard print function for goals supports current_goals_markers
  1319 variable for marking begin of proof, end of proof, start of goal; the
  1320 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1321 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1322 for example;
  1323 
  1324 
  1325 
  1326 New in Isabelle98 (January 1998)
  1327 --------------------------------
  1328 
  1329 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1330 
  1331 * changed lexical syntax of terms / types: dots made part of long
  1332 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1333 
  1334 * simpset (and claset) reference variable replaced by functions
  1335 simpset / simpset_ref;
  1336 
  1337 * no longer supports theory aliases (via merge) and non-trivial
  1338 implicit merge of thms' signatures;
  1339 
  1340 * most internal names of constants changed due to qualified names;
  1341 
  1342 * changed Pure/Sequence interface (see Pure/seq.ML);
  1343 
  1344 
  1345 *** General Changes ***
  1346 
  1347 * hierachically structured name spaces (for consts, types, axms, thms
  1348 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1349 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1350 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1351 long_names for fully qualified output names; NOTE: ML programs
  1352 (special tactics, packages etc.) referring to internal names may have
  1353 to be adapted to cope with fully qualified names; in case of severe
  1354 backward campatibility problems try setting 'global_names' at compile
  1355 time to have enrything declared within a flat name space; one may also
  1356 fine tune name declarations in theories via the 'global' and 'local'
  1357 section;
  1358 
  1359 * reimplemented the implicit simpset and claset using the new anytype
  1360 data filed in signatures; references simpset:simpset ref etc. are
  1361 replaced by functions simpset:unit->simpset and
  1362 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1363 to patch your ML files accordingly;
  1364 
  1365 * HTML output now includes theory graph data for display with Java
  1366 applet or isatool browser; data generated automatically via isatool
  1367 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1368 
  1369 * defs may now be conditional; improved rewrite_goals_tac to handle
  1370 conditional equations;
  1371 
  1372 * defs now admits additional type arguments, using TYPE('a) syntax;
  1373 
  1374 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1375 creates a new theory node; implicit merge of thms' signatures is
  1376 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1377 transfer:theory->thm->thm in (rare) cases;
  1378 
  1379 * improved handling of draft signatures / theories; draft thms (and
  1380 ctyps, cterms) are automatically promoted to real ones;
  1381 
  1382 * slightly changed interfaces for oracles: admit many per theory, named
  1383 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1384 
  1385 * print_goals: optional output of const types (set show_consts and
  1386 show_types);
  1387 
  1388 * improved output of warnings (###) and errors (***);
  1389 
  1390 * subgoal_tac displays a warning if the new subgoal has type variables;
  1391 
  1392 * removed old README and Makefiles;
  1393 
  1394 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1395 
  1396 * removed obsolete init_pps and init_database;
  1397 
  1398 * deleted the obsolete tactical STATE, which was declared by
  1399     fun STATE tacfun st = tacfun st st;
  1400 
  1401 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1402 (which abbreviates $HOME);
  1403 
  1404 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1405 use isatool fixseq to adapt your ML programs (this works for fully
  1406 qualified references to the Sequence structure only!);
  1407 
  1408 * use_thy no longer requires writable current directory; it always
  1409 reloads .ML *and* .thy file, if either one is out of date;
  1410 
  1411 
  1412 *** Classical Reasoner ***
  1413 
  1414 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1415 tactics that use classical reasoning to simplify a subgoal without
  1416 splitting it into several subgoals;
  1417 
  1418 * Safe_tac: like safe_tac but uses the default claset;
  1419 
  1420 
  1421 *** Simplifier ***
  1422 
  1423 * added simplification meta rules:
  1424     (asm_)(full_)simplify: simpset -> thm -> thm;
  1425 
  1426 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1427 logics (again);
  1428 
  1429 * added prems argument to simplification procedures;
  1430 
  1431 * HOL, FOL, ZF: added infix function `addsplits':
  1432   instead of `<simpset> setloop (split_tac <thms>)'
  1433   you can simply write `<simpset> addsplits <thms>'
  1434 
  1435 
  1436 *** Syntax ***
  1437 
  1438 * TYPE('a) syntax for type reflection terms;
  1439 
  1440 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1441 
  1442 * pretty printer: changed order of mixfix annotation preference (again!);
  1443 
  1444 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1445 
  1446 
  1447 *** HOL ***
  1448 
  1449 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1450   with `addloop' of the simplifier to faciliate case splitting in premises.
  1451 
  1452 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1453 
  1454 * HOL/Auth: new protocol proofs including some for the Internet
  1455   protocol TLS;
  1456 
  1457 * HOL/Map: new theory of `maps' a la VDM;
  1458 
  1459 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1460 cancelling out common nat summands from =, <, <= (in)equalities, or
  1461 differences; simplification procedures nat_cancel_factor for
  1462 cancelling common factor from =, <, <= (in)equalities over natural
  1463 sums; nat_cancel contains both kinds of procedures, it is installed by
  1464 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1465 
  1466 * HOL/simplifier: terms of the form
  1467   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1468   are rewritten to
  1469   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1470   and those of the form
  1471   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1472   are rewritten to
  1473   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1474 
  1475 * HOL/datatype
  1476   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1477 
  1478   P(t_case f1 ... fn x) =
  1479      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1480         ...
  1481        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1482      )
  1483 
  1484   and a theorem `split_t_case_asm' of the form
  1485 
  1486   P(t_case f1 ... fn x) =
  1487     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1488         ...
  1489        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1490      )
  1491   which can be added to a simpset via `addsplits'. The existing theorems
  1492   expand_list_case and expand_option_case have been renamed to
  1493   split_list_case and split_option_case.
  1494 
  1495 * HOL/Arithmetic:
  1496   - `pred n' is automatically converted to `n-1'.
  1497     Users are strongly encouraged not to use `pred' any longer,
  1498     because it will disappear altogether at some point.
  1499   - Users are strongly encouraged to write "0 < n" rather than
  1500     "n ~= 0". Theorems and proof tools have been modified towards this
  1501     `standard'.
  1502 
  1503 * HOL/Lists:
  1504   the function "set_of_list" has been renamed "set" (and its theorems too);
  1505   the function "nth" now takes its arguments in the reverse order and
  1506   has acquired the infix notation "!" as in "xs!n".
  1507 
  1508 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1509 
  1510 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1511   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1512 
  1513 * HOL/record: extensible records with schematic structural subtyping
  1514 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1515 still lacks various theorems and concrete record syntax;
  1516 
  1517 
  1518 *** HOLCF ***
  1519 
  1520 * removed "axioms" and "generated by" sections;
  1521 
  1522 * replaced "ops" section by extended "consts" section, which is capable of
  1523   handling the continuous function space "->" directly;
  1524 
  1525 * domain package:
  1526   . proves theorems immediately and stores them in the theory,
  1527   . creates hierachical name space,
  1528   . now uses normal mixfix annotations (instead of cinfix...),
  1529   . minor changes to some names and values (for consistency),
  1530   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1531   . separator between mutual domain defs: changed "," to "and",
  1532   . improved handling of sort constraints;  now they have to
  1533     appear on the left-hand side of the equations only;
  1534 
  1535 * fixed LAM <x,y,zs>.b syntax;
  1536 
  1537 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1538 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1539 
  1540 
  1541 *** FOL and ZF ***
  1542 
  1543 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1544   with `addloop' of the simplifier to faciliate case splitting in premises.
  1545 
  1546 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1547 in HOL, they strip ALL and --> from proved theorems;
  1548 
  1549 
  1550 
  1551 New in Isabelle94-8 (May 1997)
  1552 ------------------------------
  1553 
  1554 *** General Changes ***
  1555 
  1556 * new utilities to build / run / maintain Isabelle etc. (in parts
  1557 still somewhat experimental); old Makefiles etc. still functional;
  1558 
  1559 * new 'Isabelle System Manual';
  1560 
  1561 * INSTALL text, together with ./configure and ./build scripts;
  1562 
  1563 * reimplemented type inference for greater efficiency, better error
  1564 messages and clean internal interface;
  1565 
  1566 * prlim command for dealing with lots of subgoals (an easier way of
  1567 setting goals_limit);
  1568 
  1569 
  1570 *** Syntax ***
  1571 
  1572 * supports alternative (named) syntax tables (parser and pretty
  1573 printer); internal interface is provided by add_modesyntax(_i);
  1574 
  1575 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1576 be used in conjunction with the Isabelle symbol font; uses the
  1577 "symbols" syntax table;
  1578 
  1579 * added token_translation interface (may translate name tokens in
  1580 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1581 the current print_mode); IMPORTANT: user print translation functions
  1582 are responsible for marking newly introduced bounds
  1583 (Syntax.mark_boundT);
  1584 
  1585 * token translations for modes "xterm" and "xterm_color" that display
  1586 names in bold, underline etc. or colors (which requires a color
  1587 version of xterm);
  1588 
  1589 * infixes may now be declared with names independent of their syntax;
  1590 
  1591 * added typed_print_translation (like print_translation, but may
  1592 access type of constant);
  1593 
  1594 
  1595 *** Classical Reasoner ***
  1596 
  1597 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1598 some limitations.  Blast_tac...
  1599   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1600   + ignores elimination rules that don't have the correct format
  1601         (the conclusion MUST be a formula variable)
  1602   + ignores types, which can make HOL proofs fail
  1603   + rules must not require higher-order unification, e.g. apply_type in ZF
  1604     [message "Function Var's argument not a bound variable" relates to this]
  1605   + its proof strategy is more general but can actually be slower
  1606 
  1607 * substitution with equality assumptions no longer permutes other
  1608 assumptions;
  1609 
  1610 * minor changes in semantics of addafter (now called addaltern); renamed
  1611 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1612 (and access functions for it);
  1613 
  1614 * improved combination of classical reasoner and simplifier:
  1615   + functions for handling clasimpsets
  1616   + improvement of addss: now the simplifier is called _after_ the
  1617     safe steps.
  1618   + safe variant of addss called addSss: uses safe simplifications
  1619     _during_ the safe steps. It is more complete as it allows multiple
  1620     instantiations of unknowns (e.g. with slow_tac).
  1621 
  1622 *** Simplifier ***
  1623 
  1624 * added interface for simplification procedures (functions that
  1625 produce *proven* rewrite rules on the fly, depending on current
  1626 redex);
  1627 
  1628 * ordering on terms as parameter (used for ordered rewriting);
  1629 
  1630 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1631 
  1632 * the solver is now split into a safe and an unsafe part.
  1633 This should be invisible for the normal user, except that the
  1634 functions setsolver and addsolver have been renamed to setSolver and
  1635 addSolver; added safe_asm_full_simp_tac;
  1636 
  1637 
  1638 *** HOL ***
  1639 
  1640 * a generic induction tactic `induct_tac' which works for all datatypes and
  1641 also for type `nat';
  1642 
  1643 * a generic case distinction tactic `exhaust_tac' which works for all
  1644 datatypes and also for type `nat';
  1645 
  1646 * each datatype comes with a function `size';
  1647 
  1648 * patterns in case expressions allow tuple patterns as arguments to
  1649 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1650 
  1651 * primrec now also works with type nat;
  1652 
  1653 * recdef: a new declaration form, allows general recursive functions to be
  1654 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1655 
  1656 * the constant for negation has been renamed from "not" to "Not" to
  1657 harmonize with FOL, ZF, LK, etc.;
  1658 
  1659 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1660 infinite lists;
  1661 
  1662 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1663 
  1664 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1665 problems in commutative rings, using axiomatic type classes for + and *;
  1666 
  1667 * more examples in HOL/MiniML and HOL/Auth;
  1668 
  1669 * more default rewrite rules for quantifiers, union/intersection;
  1670 
  1671 * a new constant `arbitrary == @x.False';
  1672 
  1673 * HOLCF/IOA replaces old HOL/IOA;
  1674 
  1675 * HOLCF changes: derived all rules and arities
  1676   + axiomatic type classes instead of classes
  1677   + typedef instead of faking type definitions
  1678   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1679   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1680   + eliminated the types void, one, tr
  1681   + use unit lift and bool lift (with translations) instead of one and tr
  1682   + eliminated blift from Lift3.thy (use Def instead of blift)
  1683   all eliminated rules are derived as theorems --> no visible changes ;
  1684 
  1685 
  1686 *** ZF ***
  1687 
  1688 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1689 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1690 as ZF_cs addSIs [equalityI];
  1691 
  1692 
  1693 
  1694 New in Isabelle94-7 (November 96)
  1695 ---------------------------------
  1696 
  1697 * allowing negative levels (as offsets) in prlev and choplev;
  1698 
  1699 * super-linear speedup for large simplifications;
  1700 
  1701 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1702 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1703 FAIL); can suppress it using the command Delsimps (ex_simps @
  1704 all_simps); De Morgan laws are also now included, by default;
  1705 
  1706 * improved printing of ==>  :  ~:
  1707 
  1708 * new object-logic "Sequents" adds linear logic, while replacing LK
  1709 and Modal (thanks to Sara Kalvala);
  1710 
  1711 * HOL/Auth: correctness proofs for authentication protocols;
  1712 
  1713 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1714 examples on HOL/Auth);
  1715 
  1716 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1717 the rewriter and classical reasoner simultaneously;
  1718 
  1719 * function uresult no longer returns theorems in "standard" format;
  1720 regain previous version by: val uresult = standard o uresult;
  1721 
  1722 
  1723 
  1724 New in Isabelle94-6
  1725 -------------------
  1726 
  1727 * oracles -- these establish an interface between Isabelle and trusted
  1728 external reasoners, which may deliver results as theorems;
  1729 
  1730 * proof objects (in particular record all uses of oracles);
  1731 
  1732 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1733 
  1734 * "constdefs" section in theory files;
  1735 
  1736 * "primrec" section (HOL) no longer requires names;
  1737 
  1738 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1739 
  1740 
  1741 
  1742 New in Isabelle94-5
  1743 -------------------
  1744 
  1745 * reduced space requirements;
  1746 
  1747 * automatic HTML generation from theories;
  1748 
  1749 * theory files no longer require "..." (quotes) around most types;
  1750 
  1751 * new examples, including two proofs of the Church-Rosser theorem;
  1752 
  1753 * non-curried (1994) version of HOL is no longer distributed;
  1754 
  1755 
  1756 
  1757 New in Isabelle94-4
  1758 -------------------
  1759 
  1760 * greatly reduced space requirements;
  1761 
  1762 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1763 
  1764 * searchable theorem database (see the section "Retrieving theorems" on
  1765 page 8 of the Reference Manual);
  1766 
  1767 * new examples, including Grabczewski's monumental case study of the
  1768 Axiom of Choice;
  1769 
  1770 * The previous version of HOL renamed to Old_HOL;
  1771 
  1772 * The new version of HOL (previously called CHOL) uses a curried syntax
  1773 for functions.  Application looks like f a b instead of f(a,b);
  1774 
  1775 * Mutually recursive inductive definitions finally work in HOL;
  1776 
  1777 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1778 translates to the operator "split";
  1779 
  1780 
  1781 
  1782 New in Isabelle94-3
  1783 -------------------
  1784 
  1785 * new infix operator, addss, allowing the classical reasoner to
  1786 perform simplification at each step of its search.  Example:
  1787         fast_tac (cs addss ss)
  1788 
  1789 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1790 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1791 look like (a,b) instead of <a,b>;
  1792 
  1793 * PLEASE NOTE: CHOL will eventually replace HOL!
  1794 
  1795 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1796 It translates to the operator "split".  A new theory of integers is available;
  1797 
  1798 * In ZF, integer numerals now denote two's-complement binary integers.
  1799 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1800 
  1801 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1802 of the Axiom of Choice;
  1803 
  1804 
  1805 
  1806 New in Isabelle94-2
  1807 -------------------
  1808 
  1809 * Significantly faster resolution;
  1810 
  1811 * the different sections in a .thy file can now be mixed and repeated
  1812 freely;
  1813 
  1814 * Database of theorems for FOL, HOL and ZF.  New
  1815 commands including qed, qed_goal and bind_thm store theorems in the database.
  1816 
  1817 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1818 a given theory (thms_of), or find out what theory a theorem was proved in
  1819 (theory_of_thm);
  1820 
  1821 * Bugs fixed in the inductive definition and datatype packages;
  1822 
  1823 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1824 and HOL_dup_cs obsolete;
  1825 
  1826 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1827 have been removed;
  1828 
  1829 * Simpler definition of function space in ZF;
  1830 
  1831 * new results about cardinal and ordinal arithmetic in ZF;
  1832 
  1833 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1834 types;
  1835 
  1836 
  1837 $Id$