NEWS
author paulson
Mon May 21 12:51:15 2001 +0200 (2001-05-21)
changeset 11314 f6eebbbed449
parent 11307 891fbd3f4881
child 11361 879e53d92f51
permissions -rw-r--r--
ZF: division
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 * HOL: introduced f^n = f o ... o f
     5   WARNING: due to the limits of Isabelle's type classes, ^ on functions and
     6   relations has too general a domain, namely ('a * 'b)set and 'a => 'b.
     7   This means that it may be necessary to attach explicit type constraints.
     8 
     9 * Classical reasoner: renamed addaltern to addafter, addSaltern to addSafter
    10 
    11 * HOL: added safe wrapper "split_conv_tac" to claset. EXISTING PROOFS MAY FAIL
    12 
    13 * HOL: made split_all_tac safe. EXISTING PROOFS MAY FAIL OR LOOP, so in this
    14   (rare) case use   delSWrapper "split_all_tac" addSbefore 
    15                     ("unsafe_split_all_tac", unsafe_split_all_tac)
    16 
    17 * ZF: the integer library now covers quotients and remainders, with many laws
    18 relating division to addition, multiplication, etc.;
    19 
    20 
    21 New in Isabelle99-2 (February 2001)
    22 -----------------------------------
    23 
    24 *** Overview of INCOMPATIBILITIES ***
    25 
    26 * HOL: please note that theories in the Library and elsewhere often use the
    27 new-style (Isar) format; to refer to their theorems in an ML script you must
    28 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
    29 
    30 * HOL: inductive package no longer splits induction rule aggressively,
    31 but only as far as specified by the introductions given; the old
    32 format may be recovered via ML function complete_split_rule or attribute
    33 'split_rule (complete)';
    34 
    35 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
    36 gfp_Tarski to gfp_unfold;
    37 
    38 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
    39 
    40 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
    41 relation); infix "^^" has been renamed "``"; infix "``" has been
    42 renamed "`"; "univalent" has been renamed "single_valued";
    43 
    44 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
    45 operation;
    46 
    47 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
    48 
    49 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
    50 
    51 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
    52 consequence, it is no longer monotonic wrt. the local goal context
    53 (which is now passed through the inductive cases);
    54 
    55 * Document preparation: renamed standard symbols \<ll> to \<lless> and
    56 \<gg> to \<ggreater>;
    57 
    58 
    59 *** Document preparation ***
    60 
    61 * \isabellestyle{NAME} selects version of Isabelle output (currently
    62 available: are "it" for near math-mode best-style output, "sl" for
    63 slanted text style, and "tt" for plain type-writer; if no
    64 \isabellestyle command is given, output is according to slanted
    65 type-writer);
    66 
    67 * support sub/super scripts (for single symbols only), input syntax is
    68 like this: "A\<^sup>*" or "A\<^sup>\<star>";
    69 
    70 * some more standard symbols; see Appendix A of the system manual for
    71 the complete list of symbols defined in isabellesym.sty;
    72 
    73 * improved isabelle style files; more abstract symbol implementation
    74 (should now use \isamath{...} and \isatext{...} in custom symbol
    75 definitions);
    76 
    77 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
    78 state; Note that presentation of goal states does not conform to
    79 actual human-readable proof documents.  Please do not include goal
    80 states into document output unless you really know what you are doing!
    81 
    82 * proper indentation of antiquoted output with proportional LaTeX
    83 fonts;
    84 
    85 * no_document ML operator temporarily disables LaTeX document
    86 generation;
    87 
    88 * isatool unsymbolize tunes sources for plain ASCII communication;
    89 
    90 
    91 *** Isar ***
    92 
    93 * Pure: Isar now suffers initial goal statements to contain unbound
    94 schematic variables (this does not conform to actual readable proof
    95 documents, due to unpredictable outcome and non-compositional proof
    96 checking); users who know what they are doing may use schematic goals
    97 for Prolog-style synthesis of proven results;
    98 
    99 * Pure: assumption method (an implicit finishing) now handles actual
   100 rules as well;
   101 
   102 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   103 initial goal, declare "that" only as Pure intro (only for single
   104 steps); the "that" rule assumption may now be involved in implicit
   105 finishing, thus ".." becomes a feasible for trivial obtains;
   106 
   107 * Pure: default proof step now includes 'intro_classes'; thus trivial
   108 instance proofs may be performed by "..";
   109 
   110 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   111 statements as well;
   112 
   113 * Pure: more robust selection of calculational rules;
   114 
   115 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   116 rule (as well as the assumption rule);
   117 
   118 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   119 lemmas, using the graph browser tool;
   120 
   121 * Pure: predict failure of "show" in interactive mode;
   122 
   123 * Pure: 'thms_containing' now takes actual terms as arguments;
   124 
   125 * HOL: improved method 'induct' --- now handles non-atomic goals
   126 (potential INCOMPATIBILITY); tuned error handling;
   127 
   128 * HOL: cases and induct rules now provide explicit hints about the
   129 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   130 any remaining facts are inserted into the goal verbatim;
   131 
   132 * HOL: local contexts (aka cases) may now contain term bindings as
   133 well; the 'cases' and 'induct' methods new provide a ?case binding for
   134 the result to be shown in each case;
   135 
   136 * HOL: added 'recdef_tc' command;
   137 
   138 * isatool convert assists in eliminating legacy ML scripts;
   139 
   140 
   141 *** HOL ***
   142 
   143 * HOL/Library: a collection of generic theories to be used together
   144 with main HOL; the theory loader path already includes this directory
   145 by default; the following existing theories have been moved here:
   146 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   147 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   148 
   149 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   150 modelling and verification task performed in Isabelle/HOL +
   151 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   152 
   153 * HOL/Algebra: special summation operator SUM no longer exists, it has
   154 been replaced by setsum; infix 'assoc' now has priority 50 (like
   155 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   156 'domain', this makes the theory consistent with mathematical
   157 literature;
   158 
   159 * HOL basics: added overloaded operations "inverse" and "divide"
   160 (infix "/"), syntax for generic "abs" operation, generic summation
   161 operator \<Sum>;
   162 
   163 * HOL/typedef: simplified package, provide more useful rules (see also
   164 HOL/subset.thy);
   165 
   166 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   167 now expressed as a proper nested rule (old-style tactic scripts may
   168 require atomize_strip_tac to cope with non-atomic premises);
   169 
   170 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   171 to "split_conv" (old name still available for compatibility);
   172 
   173 * HOL: improved concrete syntax for strings (e.g. allows translation
   174 rules with string literals);
   175 
   176 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   177 and Fleuriot's mechanization of analysis;
   178 
   179 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   180 
   181 
   182 *** CTT ***
   183 
   184 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   185 "lam" is displayed as TWO lambda-symbols
   186 
   187 * CTT: theory Main now available, containing everything (that is, Bool
   188 and Arith);
   189 
   190 
   191 *** General ***
   192 
   193 * Pure: the Simplifier has been implemented properly as a derived rule
   194 outside of the actual kernel (at last!); the overall performance
   195 penalty in practical applications is about 50%, while reliability of
   196 the Isabelle inference kernel has been greatly improved;
   197 
   198 * print modes "brackets" and "no_brackets" control output of nested =>
   199 (types) and ==> (props); the default behaviour is "brackets";
   200 
   201 * Provers: fast_tac (and friends) now handle actual object-logic rules
   202 as assumptions as well;
   203 
   204 * system: support Poly/ML 4.0;
   205 
   206 * system: isatool install handles KDE version 1 or 2;
   207 
   208 
   209 
   210 New in Isabelle99-1 (October 2000)
   211 ----------------------------------
   212 
   213 *** Overview of INCOMPATIBILITIES ***
   214 
   215 * HOL: simplification of natural numbers is much changed; to partly
   216 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   217 issue the following ML commands:
   218 
   219   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   220   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   221 
   222 * HOL: simplification no longer dives into case-expressions; this is
   223 controlled by "t.weak_case_cong" for each datatype t;
   224 
   225 * HOL: nat_less_induct renamed to less_induct;
   226 
   227 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   228 fixsome to patch .thy and .ML sources automatically;
   229 
   230   select_equality  -> some_equality
   231   select_eq_Ex     -> some_eq_ex
   232   selectI2EX       -> someI2_ex
   233   selectI2         -> someI2
   234   selectI          -> someI
   235   select1_equality -> some1_equality
   236   Eps_sym_eq       -> some_sym_eq_trivial
   237   Eps_eq           -> some_eq_trivial
   238 
   239 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   240 
   241 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   242 instead);
   243 
   244 * HOL: the recursion equations generated by 'recdef' are now called
   245 f.simps instead of f.rules;
   246 
   247 * HOL: qed_spec_mp now also handles bounded ALL as well;
   248 
   249 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   250 sometimes be needed;
   251 
   252 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   253 
   254 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   255 
   256 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   257 product is now "<*>" instead of "Times"; the lexicographic product is
   258 now "<*lex*>" instead of "**";
   259 
   260 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   261 of main HOL, but was unused); better use HOL's datatype package;
   262 
   263 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   264 the old syntax may be recovered as follows:
   265 
   266   syntax (symbols)
   267     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   268       (infixl "\\<oplus>" 100)
   269 
   270 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   271 
   272 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   273 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   274 internally;
   275 
   276 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   277 changed from A/r to A//r;
   278 
   279 * ZF: new treatment of arithmetic (nat & int) may break some old
   280 proofs;
   281 
   282 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   283 rulify -> rule_format, elimify -> elim_format, ...);
   284 
   285 * Isar/Provers: intro/elim/dest attributes changed; renamed
   286 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   287 should have to change intro!! to intro? only); replaced "delrule" by
   288 "rule del";
   289 
   290 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   291 
   292 * Provers: strengthened force_tac by using new first_best_tac;
   293 
   294 * LaTeX document preparation: several changes of isabelle.sty (see
   295 lib/texinputs);
   296 
   297 
   298 *** Document preparation ***
   299 
   300 * formal comments (text blocks etc.) in new-style theories may now
   301 contain antiquotations of thm/prop/term/typ/text to be presented
   302 according to latex print mode; concrete syntax is like this:
   303 @{term[show_types] "f(x) = a + x"};
   304 
   305 * isatool mkdir provides easy setup of Isabelle session directories,
   306 including proper document sources;
   307 
   308 * generated LaTeX sources are now deleted after successful run
   309 (isatool document -c); may retain a copy somewhere else via -D option
   310 of isatool usedir;
   311 
   312 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   313 style files, achieving self-contained LaTeX sources and simplifying
   314 LaTeX debugging;
   315 
   316 * old-style theories now produce (crude) LaTeX output as well;
   317 
   318 * browser info session directories are now self-contained (may be put
   319 on WWW server seperately); improved graphs of nested sessions; removed
   320 graph for 'all sessions';
   321 
   322 * several improvements in isabelle style files; \isabellestyle{it}
   323 produces fake math mode output; \isamarkupheader is now \section by
   324 default; see lib/texinputs/isabelle.sty etc.;
   325 
   326 
   327 *** Isar ***
   328 
   329 * Isar/Pure: local results and corresponding term bindings are now
   330 subject to Hindley-Milner polymorphism (similar to ML); this
   331 accommodates incremental type-inference very nicely;
   332 
   333 * Isar/Pure: new derived language element 'obtain' supports
   334 generalized existence reasoning;
   335 
   336 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   337 support accumulation of results, without applying any rules yet;
   338 useful to collect intermediate results without explicit name
   339 references, and for use with transitivity rules with more than 2
   340 premises;
   341 
   342 * Isar/Pure: scalable support for case-analysis type proofs: new
   343 'case' language element refers to local contexts symbolically, as
   344 produced by certain proof methods; internally, case names are attached
   345 to theorems as "tags";
   346 
   347 * Isar/Pure: theory command 'hide' removes declarations from
   348 class/type/const name spaces;
   349 
   350 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   351 indicate potential overloading;
   352 
   353 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   354 
   355 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   356 "{a,b,c}" instead of {a,b,c};
   357 
   358 * Isar/Pure now provides its own version of intro/elim/dest
   359 attributes; useful for building new logics, but beware of confusion
   360 with the version in Provers/classical;
   361 
   362 * Isar/Pure: the local context of (non-atomic) goals is provided via
   363 case name 'antecedent';
   364 
   365 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   366 to the current context is now done automatically);
   367 
   368 * Isar/Pure: theory command 'method_setup' provides a simple interface
   369 for definining proof methods in ML;
   370 
   371 * Isar/Provers: intro/elim/dest attributes changed; renamed
   372 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   373 most cases, one should have to change intro!! to intro? only);
   374 replaced "delrule" by "rule del";
   375 
   376 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   377 'symmetric' attribute (the latter supercedes [RS sym]);
   378 
   379 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   380 method modifier); 'simp' method: 'only:' modifier removes loopers as
   381 well (including splits);
   382 
   383 * Isar/Provers: Simplifier and Classical methods now support all kind
   384 of modifiers used in the past, including 'cong', 'iff', etc.
   385 
   386 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   387 of Simplifier and Classical reasoner);
   388 
   389 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   390 now support named cases; major packages (inductive, datatype, primrec,
   391 recdef) support case names and properly name parameters;
   392 
   393 * Isar/HOL: new transitivity rules for substitution in inequalities --
   394 monotonicity conditions are extracted to be proven at end of
   395 calculations;
   396 
   397 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   398 method anyway;
   399 
   400 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   401 split_if split_if_asm; datatype package provides theorems foo.splits =
   402 foo.split foo.split_asm for each datatype;
   403 
   404 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   405 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   406 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   407 use "(cases (simplified))" method in proper proof texts);
   408 
   409 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   410 
   411 * Isar: names of theorems etc. may be natural numbers as well;
   412 
   413 * Isar: 'pr' command: optional arguments for goals_limit and
   414 ProofContext.prems_limit; no longer prints theory contexts, but only
   415 proof states;
   416 
   417 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   418 additional print modes to be specified; e.g. "pr(latex)" will print
   419 proof state according to the Isabelle LaTeX style;
   420 
   421 * Isar: improved support for emulating tactic scripts, including proof
   422 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   423 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   424 (for HOL datatypes);
   425 
   426 * Isar: simplified (more robust) goal selection of proof methods: 1st
   427 goal, all goals, or explicit goal specifier (tactic emulation); thus
   428 'proof method scripts' have to be in depth-first order;
   429 
   430 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   431 
   432 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   433 should instead use individual commands for printing items
   434 (print_commands, print_methods etc.);
   435 
   436 * Isar: added 'nothing' --- the empty list of theorems;
   437 
   438 
   439 *** HOL ***
   440 
   441 * HOL/MicroJava: formalization of a fragment of Java, together with a
   442 corresponding virtual machine and a specification of its bytecode
   443 verifier and a lightweight bytecode verifier, including proofs of
   444 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   445 Cornelia Pusch (see also the homepage of project Bali at
   446 http://isabelle.in.tum.de/Bali/);
   447 
   448 * HOL/Algebra: new theory of rings and univariate polynomials, by
   449 Clemens Ballarin;
   450 
   451 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   452 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   453 Rasmussen;
   454 
   455 * HOL/Lattice: fundamental concepts of lattice theory and order
   456 structures, including duals, properties of bounds versus algebraic
   457 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   458 Theorem for complete lattices etc.; may also serve as a demonstration
   459 for abstract algebraic reasoning using axiomatic type classes, and
   460 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   461 
   462 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   463 von Oheimb;
   464 
   465 * HOL/IMPP: extension of IMP with local variables and mutually
   466 recursive procedures, by David von Oheimb;
   467 
   468 * HOL/Lambda: converted into new-style theory and document;
   469 
   470 * HOL/ex/Multiquote: example of multiple nested quotations and
   471 anti-quotations -- basically a generalized version of de-Bruijn
   472 representation; very useful in avoiding lifting of operations;
   473 
   474 * HOL/record: added general record equality rule to simpset; fixed
   475 select-update simplification procedure to handle extended records as
   476 well; admit "r" as field name;
   477 
   478 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   479 other numeric types and also as the identity of groups, rings, etc.;
   480 
   481 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   482 Types nat and int belong to this axclass;
   483 
   484 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   485    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   486    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   487   two terms #m*u and #n*u are replaced by #(m+n)*u
   488     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   489   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   490     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   491 
   492 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   493 powerful prover for predicate logic but knows nothing of clasets; see
   494 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   495 
   496 * HOL: new version of "case_tac" subsumes both boolean case split and
   497 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   498 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   499 
   500 * HOL: simplification no longer dives into case-expressions: only the
   501 selector expression is simplified, but not the remaining arms; to
   502 enable full simplification of case-expressions for datatype t, you may
   503 remove t.weak_case_cong from the simpset, either globally (Delcongs
   504 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   505 
   506 * HOL/recdef: the recursion equations generated by 'recdef' for
   507 function 'f' are now called f.simps instead of f.rules; if all
   508 termination conditions are proved automatically, these simplification
   509 rules are added to the simpset, as in primrec; rules may be named
   510 individually as well, resulting in a separate list of theorems for
   511 each equation;
   512 
   513 * HOL/While is a new theory that provides a while-combinator. It
   514 permits the definition of tail-recursive functions without the
   515 provision of a termination measure. The latter is necessary once the
   516 invariant proof rule for while is applied.
   517 
   518 * HOL: new (overloaded) notation for the set of elements below/above
   519 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   520 
   521 * HOL: theorems impI, allI, ballI bound as "strip";
   522 
   523 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   524 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   525 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   526 
   527 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   528 
   529 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   530 main HOL, but was unused);
   531 
   532 * HOL: fewer consts declared as global (e.g. have to refer to
   533 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   534 
   535 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   536 in case of overlap with user translations (e.g. judgements over
   537 tuples); (note that the underlying logical represenation is still
   538 bogus);
   539 
   540 
   541 *** ZF ***
   542 
   543 * ZF: simplification automatically cancels common terms in arithmetic
   544 expressions over nat and int;
   545 
   546 * ZF: new treatment of nat to minimize type-checking: all operators
   547 coerce their operands to a natural number using the function natify,
   548 making the algebraic laws unconditional;
   549 
   550 * ZF: as above, for int: operators coerce their operands to an integer
   551 using the function intify;
   552 
   553 * ZF: the integer library now contains many of the usual laws for the
   554 orderings, including $<=, and monotonicity laws for $+ and $*;
   555 
   556 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   557 simplification;
   558 
   559 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   560 to the simplifier and classical reasoner simultaneously;
   561 
   562 
   563 *** General ***
   564 
   565 * Provers: blast_tac now handles actual object-logic rules as
   566 assumptions; note that auto_tac uses blast_tac internally as well;
   567 
   568 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   569 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   570 
   571 * Provers: delrules now handles destruct rules as well (no longer need
   572 explicit make_elim);
   573 
   574 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   575   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   576 use instead the strong form,
   577   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   578 in HOL, FOL and ZF the function cla_make_elim will create such rules
   579 from destruct-rules;
   580 
   581 * Provers: Simplifier.easy_setup provides a fast path to basic
   582 Simplifier setup for new object-logics;
   583 
   584 * Pure: AST translation rules no longer require constant head on LHS;
   585 
   586 * Pure: improved name spaces: ambiguous output is qualified; support
   587 for hiding of names;
   588 
   589 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   590 XSYMBOL_HOME; no longer need to do manual configuration in most
   591 situations;
   592 
   593 * system: compression of ML heaps images may now be controlled via -c
   594 option of isabelle and isatool usedir (currently only observed by
   595 Poly/ML);
   596 
   597 * system: isatool installfonts may handle X-Symbol fonts as well (very
   598 useful for remote X11);
   599 
   600 * system: provide TAGS file for Isabelle sources;
   601 
   602 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   603 order;
   604 
   605 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   606 timing flag supersedes proof_timing and Toplevel.trace;
   607 
   608 * ML: new combinators |>> and |>>> for incremental transformations
   609 with secondary results (e.g. certain theory extensions):
   610 
   611 * ML: PureThy.add_defs gets additional argument to indicate potential
   612 overloading (usually false);
   613 
   614 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   615 results;
   616 
   617 
   618 
   619 New in Isabelle99 (October 1999)
   620 --------------------------------
   621 
   622 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   623 
   624 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   625 are no longer simplified.  (This allows the simplifier to unfold recursive
   626 functional programs.)  To restore the old behaviour, declare
   627 
   628     Delcongs [if_weak_cong];
   629 
   630 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   631 complement;
   632 
   633 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   634 
   635 * HOL/datatype: mutual_induct_tac no longer exists --
   636   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   637 
   638 * HOL/typedef: fixed type inference for representing set; type
   639 arguments now have to occur explicitly on the rhs as type constraints;
   640 
   641 * ZF: The con_defs part of an inductive definition may no longer refer
   642 to constants declared in the same theory;
   643 
   644 * HOL, ZF: the function mk_cases, generated by the inductive
   645 definition package, has lost an argument.  To simplify its result, it
   646 uses the default simpset instead of a supplied list of theorems.
   647 
   648 * HOL/List: the constructors of type list are now Nil and Cons;
   649 
   650 * Simplifier: the type of the infix ML functions
   651         setSSolver addSSolver setSolver addSolver
   652 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   653 for packaging solvers. A solver is created via
   654         mk_solver: string -> (thm list -> int -> tactic) -> solver
   655 where the string argument is only a comment.
   656 
   657 
   658 *** Proof tools ***
   659 
   660 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   661 decision procedure for linear arithmetic. Currently it is used for
   662 types `nat', `int', and `real' in HOL (see below); it can, should and
   663 will be instantiated for other types and logics as well.
   664 
   665 * The simplifier now accepts rewrite rules with flexible heads, eg
   666      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   667   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   668   matching.
   669 
   670 
   671 *** General ***
   672 
   673 * New Isabelle/Isar subsystem provides an alternative to traditional
   674 tactical theorem proving; together with the ProofGeneral/isar user
   675 interface it offers an interactive environment for developing human
   676 readable proof documents (Isar == Intelligible semi-automated
   677 reasoning); for further information see isatool doc isar-ref,
   678 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   679 
   680 * improved and simplified presentation of theories: better HTML markup
   681 (including colors), graph views in several sizes; isatool usedir now
   682 provides a proper interface for user theories (via -P option); actual
   683 document preparation based on (PDF)LaTeX is available as well (for
   684 new-style theories only); see isatool doc system for more information;
   685 
   686 * native support for Proof General, both for classic Isabelle and
   687 Isabelle/Isar;
   688 
   689 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   690 using the graph browser tool;
   691 
   692 * Isabelle manuals now also available as PDF;
   693 
   694 * theory loader rewritten from scratch (may not be fully
   695 bug-compatible); old loadpath variable has been replaced by show_path,
   696 add_path, del_path, reset_path functions; new operations such as
   697 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   698 isatool doc ref);
   699 
   700 * improved isatool install: option -k creates KDE application icon,
   701 option -p DIR installs standalone binaries;
   702 
   703 * added ML_PLATFORM setting (useful for cross-platform installations);
   704 more robust handling of platform specific ML images for SML/NJ;
   705 
   706 * the settings environment is now statically scoped, i.e. it is never
   707 created again in sub-processes invoked from isabelle, isatool, or
   708 Isabelle;
   709 
   710 * path element specification '~~' refers to '$ISABELLE_HOME';
   711 
   712 * in locales, the "assumes" and "defines" parts may be omitted if
   713 empty;
   714 
   715 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   716 long arrows);
   717 
   718 * new print_mode "HTML";
   719 
   720 * new flag show_tags controls display of tags of theorems (which are
   721 basically just comments that may be attached by some tools);
   722 
   723 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   724 mode and goal output format:
   725 
   726 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   727 244c244
   728 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   729 ---
   730 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   731 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   732 181c181
   733 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   734 ---
   735 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   736 
   737 * function bind_thms stores lists of theorems (cf. bind_thm);
   738 
   739 * new shorthand tactics ftac, eatac, datac, fatac;
   740 
   741 * qed (and friends) now accept "" as result name; in that case the
   742 theorem is not stored, but proper checks and presentation of the
   743 result still apply;
   744 
   745 * theorem database now also indexes constants "Trueprop", "all",
   746 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   747 
   748 
   749 *** HOL ***
   750 
   751 ** HOL arithmetic **
   752 
   753 * There are now decision procedures for linear arithmetic over nat and
   754 int:
   755 
   756 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   757 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   758 are treated as atomic; subformulae not involving type `nat' or `int'
   759 are ignored; quantified subformulae are ignored unless they are
   760 positive universal or negative existential. The tactic has to be
   761 invoked by hand and can be a little bit slow. In particular, the
   762 running time is exponential in the number of occurrences of `min' and
   763 `max', and `-' on `nat'.
   764 
   765 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   766 (negated) (in)equalities among the premises and the conclusion into
   767 account (i.e. no compound formulae) and does not know about `min' and
   768 `max', and `-' on `nat'. It is fast and is used automatically by the
   769 simplifier.
   770 
   771 NB: At the moment, these decision procedures do not cope with mixed
   772 nat/int formulae where the two parts interact, such as `m < n ==>
   773 int(m) < int(n)'.
   774 
   775 * HOL/Numeral provides a generic theory of numerals (encoded
   776 efficiently as bit strings); setup for types nat/int/real is in place;
   777 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   778 int, existing theories and proof scripts may require a few additional
   779 type constraints;
   780 
   781 * integer division and remainder can now be performed on constant
   782 arguments;
   783 
   784 * many properties of integer multiplication, division and remainder
   785 are now available;
   786 
   787 * An interface to the Stanford Validity Checker (SVC) is available through the
   788 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   789 are proved automatically.  SVC must be installed separately, and its results
   790 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   791 invocation of the underlying oracle).  For SVC see
   792   http://verify.stanford.edu/SVC
   793 
   794 * IsaMakefile: the HOL-Real target now builds an actual image;
   795 
   796 
   797 ** HOL misc **
   798 
   799 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   800 (in Isabelle/Isar) -- by Gertrud Bauer;
   801 
   802 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   803 analysis for assembly languages with subtypes;
   804 
   805 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   806 -- avoids syntactic ambiguities and treats state, transition, and
   807 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   808 changed syntax and (many) tactics;
   809 
   810 * HOL/inductive: Now also handles more general introduction rules such
   811   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   812   theorems are now maintained within the theory (maintained via the
   813   "mono" attribute);
   814 
   815 * HOL/datatype: Now also handles arbitrarily branching datatypes
   816   (using function types) such as
   817 
   818   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   819 
   820 * HOL/record: record_simproc (part of the default simpset) takes care
   821 of selectors applied to updated records; record_split_tac is no longer
   822 part of the default claset; update_defs may now be removed from the
   823 simpset in many cases; COMPATIBILITY: old behavior achieved by
   824 
   825   claset_ref () := claset() addSWrapper record_split_wrapper;
   826   Delsimprocs [record_simproc]
   827 
   828 * HOL/typedef: fixed type inference for representing set; type
   829 arguments now have to occur explicitly on the rhs as type constraints;
   830 
   831 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   832 names rather than an ML expression;
   833 
   834 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   835 supplied later.  Program schemes can be defined, such as
   836     "While B C s = (if B s then While B C (C s) else s)"
   837 where the well-founded relation can be chosen after B and C have been given.
   838 
   839 * HOL/List: the constructors of type list are now Nil and Cons;
   840 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   841 course, ML tools referring to List.list.op # etc. have to be adapted;
   842 
   843 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   844 disabled by default; run isabelle with option -m HOL to get back to
   845 the original Gordon/HOL-style output;
   846 
   847 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   848 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   849 
   850 * HOL basic syntax simplified (more orthogonal): all variants of
   851 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   852 Eps operator is provided as well: "SOME x. P[x]";
   853 
   854 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   855 
   856 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   857 thus available for user theories;
   858 
   859 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   860 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   861 time;
   862 
   863 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   864 several times and then mp;
   865 
   866 
   867 *** LK ***
   868 
   869 * the notation <<...>> is now available as a notation for sequences of
   870 formulas;
   871 
   872 * the simplifier is now installed
   873 
   874 * the axiom system has been generalized (thanks to Soren Heilmann)
   875 
   876 * the classical reasoner now has a default rule database
   877 
   878 
   879 *** ZF ***
   880 
   881 * new primrec section allows primitive recursive functions to be given
   882 directly (as in HOL) over datatypes and the natural numbers;
   883 
   884 * new tactics induct_tac and exhaust_tac for induction (or case
   885 analysis) over datatypes and the natural numbers;
   886 
   887 * the datatype declaration of type T now defines the recursor T_rec;
   888 
   889 * simplification automatically does freeness reasoning for datatype
   890 constructors;
   891 
   892 * automatic type-inference, with AddTCs command to insert new
   893 type-checking rules;
   894 
   895 * datatype introduction rules are now added as Safe Introduction rules
   896 to the claset;
   897 
   898 * the syntax "if P then x else y" is now available in addition to
   899 if(P,x,y);
   900 
   901 
   902 *** Internal programming interfaces ***
   903 
   904 * tuned simplifier trace output; new flag debug_simp;
   905 
   906 * structures Vartab / Termtab (instances of TableFun) offer efficient
   907 tables indexed by indexname_ord / term_ord (compatible with aconv);
   908 
   909 * AxClass.axclass_tac lost the theory argument;
   910 
   911 * tuned current_goals_markers semantics: begin / end goal avoids
   912 printing empty lines;
   913 
   914 * removed prs and prs_fn hook, which was broken because it did not
   915 include \n in its semantics, forcing writeln to add one
   916 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   917 string -> unit if you really want to output text without newline;
   918 
   919 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   920 plain output, interface builders may have to enable 'isabelle_font'
   921 mode to get Isabelle font glyphs as before;
   922 
   923 * refined token_translation interface; INCOMPATIBILITY: output length
   924 now of type real instead of int;
   925 
   926 * theory loader actions may be traced via new ThyInfo.add_hook
   927 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   928 your own database of information attached to *whole* theories -- as
   929 opposed to intra-theory data slots offered via TheoryDataFun;
   930 
   931 * proper handling of dangling sort hypotheses (at last!);
   932 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   933 extra sort hypotheses that can be witnessed from the type signature;
   934 the force_strip_shyps flag is gone, any remaining shyps are simply
   935 left in the theorem (with a warning issued by strip_shyps_warning);
   936 
   937 
   938 
   939 New in Isabelle98-1 (October 1998)
   940 ----------------------------------
   941 
   942 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   943 
   944 * several changes of automated proof tools;
   945 
   946 * HOL: major changes to the inductive and datatype packages, including
   947 some minor incompatibilities of theory syntax;
   948 
   949 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   950 called `inj_on';
   951 
   952 * HOL: removed duplicate thms in Arith:
   953   less_imp_add_less  should be replaced by  trans_less_add1
   954   le_imp_add_le      should be replaced by  trans_le_add1
   955 
   956 * HOL: unary minus is now overloaded (new type constraints may be
   957 required);
   958 
   959 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   960 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   961 now taken as an integer constant.
   962 
   963 * Pure: ML function 'theory_of' renamed to 'theory';
   964 
   965 
   966 *** Proof tools ***
   967 
   968 * Simplifier:
   969   1. Asm_full_simp_tac is now more aggressive.
   970      1. It will sometimes reorient premises if that increases their power to
   971         simplify.
   972      2. It does no longer proceed strictly from left to right but may also
   973         rotate premises to achieve further simplification.
   974      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   975      old Asm_full_simp_tac in that it does not rotate premises.
   976   2. The simplifier now knows a little bit about nat-arithmetic.
   977 
   978 * Classical reasoner: wrapper mechanism for the classical reasoner now
   979 allows for selected deletion of wrappers, by introduction of names for
   980 wrapper functionals.  This implies that addbefore, addSbefore,
   981 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   982 and that adding two tactics with the same name overwrites the first
   983 one (emitting a warning).
   984   type wrapper = (int -> tactic) -> (int -> tactic)
   985   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   986   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   987   delWrapper, delSWrapper: claset *  string            -> claset
   988   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   989 
   990 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   991 semantics; addbefore now affects only the unsafe part of step_tac
   992 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   993 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   994 by Force_tac;
   995 
   996 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   997 compWrapper; added safe wrapper (and access functions for it);
   998 
   999 * HOL/split_all_tac is now much faster and fails if there is nothing
  1000 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1001 and the names of the automatically generated variables have changed.
  1002 split_all_tac has moved within claset() from unsafe wrappers to safe
  1003 wrappers, which means that !!-bound variables are split much more
  1004 aggressively, and safe_tac and clarify_tac now split such variables.
  1005 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1006 Note: the same holds for record_split_tac, which does the job of
  1007 split_all_tac for record fields.
  1008 
  1009 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1010 permanently to the default simpset using Addsplits just like
  1011 Addsimps. They can be removed via Delsplits just like
  1012 Delsimps. Lower-case versions are also available.
  1013 
  1014 * HOL/Simplifier: The rule split_if is now part of the default
  1015 simpset. This means that the simplifier will eliminate all occurrences
  1016 of if-then-else in the conclusion of a goal. To prevent this, you can
  1017 either remove split_if completely from the default simpset by
  1018 `Delsplits [split_if]' or remove it in a specific call of the
  1019 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1020 other case splitting rules to/from the default simpset: every datatype
  1021 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1022 t is the name of the datatype).
  1023 
  1024 * Classical reasoner / Simplifier combination: new force_tac (and
  1025 derivatives Force_tac, force) combines rewriting and classical
  1026 reasoning (and whatever other tools) similarly to auto_tac, but is
  1027 aimed to solve the given subgoal completely.
  1028 
  1029 
  1030 *** General ***
  1031 
  1032 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1033 and `goalw': the theory is no longer needed as an explicit argument -
  1034 the current theory context is used; assumptions are no longer returned
  1035 at the ML-level unless one of them starts with ==> or !!; it is
  1036 recommended to convert to these new commands using isatool fixgoal
  1037 (backup your sources first!);
  1038 
  1039 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1040 the current theory context, and 'theory' to lookup stored theories;
  1041 
  1042 * new theory section 'locale' for declaring constants, assumptions and
  1043 definitions that have local scope;
  1044 
  1045 * new theory section 'nonterminals' for purely syntactic types;
  1046 
  1047 * new theory section 'setup' for generic ML setup functions
  1048 (e.g. package initialization);
  1049 
  1050 * the distribution now includes Isabelle icons: see
  1051 lib/logo/isabelle-{small,tiny}.xpm;
  1052 
  1053 * isatool install - install binaries with absolute references to
  1054 ISABELLE_HOME/bin;
  1055 
  1056 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1057 
  1058 * print mode 'emacs' reserved for Isamode;
  1059 
  1060 * support multiple print (ast) translations per constant name;
  1061 
  1062 * theorems involving oracles are now printed with a suffixed [!];
  1063 
  1064 
  1065 *** HOL ***
  1066 
  1067 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1068 
  1069 * HOL/inductive package reorganized and improved: now supports mutual
  1070 definitions such as
  1071 
  1072   inductive EVEN ODD
  1073     intrs
  1074       null "0 : EVEN"
  1075       oddI "n : EVEN ==> Suc n : ODD"
  1076       evenI "n : ODD ==> Suc n : EVEN"
  1077 
  1078 new theorem list "elims" contains an elimination rule for each of the
  1079 recursive sets; inductive definitions now handle disjunctive premises
  1080 correctly (also ZF);
  1081 
  1082 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1083 "mutual_induct" no longer exists - the induction rule is always
  1084 contained in "induct";
  1085 
  1086 
  1087 * HOL/datatype package re-implemented and greatly improved: now
  1088 supports mutually recursive datatypes such as
  1089 
  1090   datatype
  1091     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1092             | SUM ('a aexp) ('a aexp)
  1093             | DIFF ('a aexp) ('a aexp)
  1094             | NUM 'a
  1095   and
  1096     'a bexp = LESS ('a aexp) ('a aexp)
  1097             | AND ('a bexp) ('a bexp)
  1098             | OR ('a bexp) ('a bexp)
  1099 
  1100 as well as indirectly recursive datatypes such as
  1101 
  1102   datatype
  1103     ('a, 'b) term = Var 'a
  1104                   | App 'b ((('a, 'b) term) list)
  1105 
  1106 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1107 induction on mutually / indirectly recursive datatypes.
  1108 
  1109 Primrec equations are now stored in theory and can be accessed via
  1110 <function_name>.simps.
  1111 
  1112 INCOMPATIBILITIES:
  1113 
  1114   - Theories using datatypes must now have theory Datatype as an
  1115     ancestor.
  1116   - The specific <typename>.induct_tac no longer exists - use the
  1117     generic induct_tac instead.
  1118   - natE has been renamed to nat.exhaust - use exhaust_tac
  1119     instead of res_inst_tac ... natE. Note that the variable
  1120     names in nat.exhaust differ from the names in natE, this
  1121     may cause some "fragile" proofs to fail.
  1122   - The theorems split_<typename>_case and split_<typename>_case_asm
  1123     have been renamed to <typename>.split and <typename>.split_asm.
  1124   - Since default sorts of type variables are now handled correctly,
  1125     some datatype definitions may have to be annotated with explicit
  1126     sort constraints.
  1127   - Primrec definitions no longer require function name and type
  1128     of recursive argument.
  1129 
  1130 Consider using isatool fixdatatype to adapt your theories and proof
  1131 scripts to the new package (backup your sources first!).
  1132 
  1133 
  1134 * HOL/record package: considerably improved implementation; now
  1135 includes concrete syntax for record types, terms, updates; theorems
  1136 for surjective pairing and splitting !!-bound record variables; proof
  1137 support is as follows:
  1138 
  1139   1) standard conversions (selectors or updates applied to record
  1140 constructor terms) are part of the standard simpset;
  1141 
  1142   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1143 made part of standard simpset and claset via addIffs;
  1144 
  1145   3) a tactic for record field splitting (record_split_tac) is part of
  1146 the standard claset (addSWrapper);
  1147 
  1148 To get a better idea about these rules you may retrieve them via
  1149 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1150 the name of your record type.
  1151 
  1152 The split tactic 3) conceptually simplifies by the following rule:
  1153 
  1154   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1155 
  1156 Thus any record variable that is bound by meta-all will automatically
  1157 blow up into some record constructor term, consequently the
  1158 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1159 solve record problems automatically.
  1160 
  1161 
  1162 * reorganized the main HOL image: HOL/Integ and String loaded by
  1163 default; theory Main includes everything;
  1164 
  1165 * automatic simplification of integer sums and comparisons, using cancellation;
  1166 
  1167 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1168 
  1169 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1170 
  1171 * many new identities for unions, intersections, set difference, etc.;
  1172 
  1173 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1174 called split_if, split_split, split_sum_case and split_nat_case (to go
  1175 with add/delsplits);
  1176 
  1177 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1178 (?x::unit) = (); this is made part of the default simpset, which COULD
  1179 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1180 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1181 unit_abs_eta_conv is added in order to counter the effect of
  1182 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1183 %u.f();
  1184 
  1185 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1186 makes more sense);
  1187 
  1188 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1189   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1190   disjointness reasoning but breaking a few old proofs.
  1191 
  1192 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1193 to 'converse' from 'inverse' (for compatibility with ZF and some
  1194 literature);
  1195 
  1196 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1197 the well-founded relation;
  1198 
  1199 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1200     Compl A.  The "Compl" syntax remains available as input syntax for this
  1201     release ONLY.
  1202 
  1203 * HOL/Update: new theory of function updates:
  1204     f(a:=b) == %x. if x=a then b else f x
  1205 may also be iterated as in f(a:=b,c:=d,...);
  1206 
  1207 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1208 
  1209 * HOL/List:
  1210   - new function list_update written xs[i:=v] that updates the i-th
  1211     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1212   - new function `upt' written [i..j(] which generates the list
  1213     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1214     bound write [i..j], which is a shorthand for [i..j+1(].
  1215   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1216 
  1217 * HOL/Arith:
  1218   - removed 'pred' (predecessor) function;
  1219   - generalized some theorems about n-1;
  1220   - many new laws about "div" and "mod";
  1221   - new laws about greatest common divisors (see theory ex/Primes);
  1222 
  1223 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1224 instead of "inverse";
  1225 
  1226 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1227   of the multiset ordering;
  1228 
  1229 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1230   (not included by default);
  1231 
  1232 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1233 
  1234 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1235   programs, i.e. different program variables may have different types.
  1236 
  1237 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1238   [previously, this check worked only if the rewrite rule was unconditional]
  1239   Now rew can involve either definitions or equalities (either == or =).
  1240 
  1241 
  1242 *** ZF ***
  1243 
  1244 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1245   only the theorems proved on ZF.ML;
  1246 
  1247 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1248   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1249   disjointness reasoning but breaking a few old proofs.
  1250 
  1251 * ZF/Update: new theory of function updates
  1252     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1253   may also be iterated as in f(a:=b,c:=d,...);
  1254 
  1255 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1256 
  1257 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1258   [previously, this check worked only if the rewrite rule was unconditional]
  1259   Now rew can involve either definitions or equalities (either == or =).
  1260 
  1261 * case_tac provided for compatibility with HOL
  1262     (like the old excluded_middle_tac, but with subgoals swapped)
  1263 
  1264 
  1265 *** Internal programming interfaces ***
  1266 
  1267 * Pure: several new basic modules made available for general use, see
  1268 also src/Pure/README;
  1269 
  1270 * improved the theory data mechanism to support encapsulation (data
  1271 kind name replaced by private Object.kind, acting as authorization
  1272 key); new type-safe user interface via functor TheoryDataFun; generic
  1273 print_data function becomes basically useless;
  1274 
  1275 * removed global_names compatibility flag -- all theory declarations
  1276 are qualified by default;
  1277 
  1278 * module Pure/Syntax now offers quote / antiquote translation
  1279 functions (useful for Hoare logic etc. with implicit dependencies);
  1280 see HOL/ex/Antiquote for an example use;
  1281 
  1282 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1283 cterm -> thm;
  1284 
  1285 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1286 subgoal;
  1287 
  1288 * Display.print_goals function moved to Locale.print_goals;
  1289 
  1290 * standard print function for goals supports current_goals_markers
  1291 variable for marking begin of proof, end of proof, start of goal; the
  1292 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1293 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1294 for example;
  1295 
  1296 
  1297 
  1298 New in Isabelle98 (January 1998)
  1299 --------------------------------
  1300 
  1301 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1302 
  1303 * changed lexical syntax of terms / types: dots made part of long
  1304 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1305 
  1306 * simpset (and claset) reference variable replaced by functions
  1307 simpset / simpset_ref;
  1308 
  1309 * no longer supports theory aliases (via merge) and non-trivial
  1310 implicit merge of thms' signatures;
  1311 
  1312 * most internal names of constants changed due to qualified names;
  1313 
  1314 * changed Pure/Sequence interface (see Pure/seq.ML);
  1315 
  1316 
  1317 *** General Changes ***
  1318 
  1319 * hierachically structured name spaces (for consts, types, axms, thms
  1320 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1321 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1322 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1323 long_names for fully qualified output names; NOTE: ML programs
  1324 (special tactics, packages etc.) referring to internal names may have
  1325 to be adapted to cope with fully qualified names; in case of severe
  1326 backward campatibility problems try setting 'global_names' at compile
  1327 time to have enrything declared within a flat name space; one may also
  1328 fine tune name declarations in theories via the 'global' and 'local'
  1329 section;
  1330 
  1331 * reimplemented the implicit simpset and claset using the new anytype
  1332 data filed in signatures; references simpset:simpset ref etc. are
  1333 replaced by functions simpset:unit->simpset and
  1334 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1335 to patch your ML files accordingly;
  1336 
  1337 * HTML output now includes theory graph data for display with Java
  1338 applet or isatool browser; data generated automatically via isatool
  1339 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1340 
  1341 * defs may now be conditional; improved rewrite_goals_tac to handle
  1342 conditional equations;
  1343 
  1344 * defs now admits additional type arguments, using TYPE('a) syntax;
  1345 
  1346 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1347 creates a new theory node; implicit merge of thms' signatures is
  1348 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1349 transfer:theory->thm->thm in (rare) cases;
  1350 
  1351 * improved handling of draft signatures / theories; draft thms (and
  1352 ctyps, cterms) are automatically promoted to real ones;
  1353 
  1354 * slightly changed interfaces for oracles: admit many per theory, named
  1355 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1356 
  1357 * print_goals: optional output of const types (set show_consts and
  1358 show_types);
  1359 
  1360 * improved output of warnings (###) and errors (***);
  1361 
  1362 * subgoal_tac displays a warning if the new subgoal has type variables;
  1363 
  1364 * removed old README and Makefiles;
  1365 
  1366 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1367 
  1368 * removed obsolete init_pps and init_database;
  1369 
  1370 * deleted the obsolete tactical STATE, which was declared by
  1371     fun STATE tacfun st = tacfun st st;
  1372 
  1373 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1374 (which abbreviates $HOME);
  1375 
  1376 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1377 use isatool fixseq to adapt your ML programs (this works for fully
  1378 qualified references to the Sequence structure only!);
  1379 
  1380 * use_thy no longer requires writable current directory; it always
  1381 reloads .ML *and* .thy file, if either one is out of date;
  1382 
  1383 
  1384 *** Classical Reasoner ***
  1385 
  1386 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1387 tactics that use classical reasoning to simplify a subgoal without
  1388 splitting it into several subgoals;
  1389 
  1390 * Safe_tac: like safe_tac but uses the default claset;
  1391 
  1392 
  1393 *** Simplifier ***
  1394 
  1395 * added simplification meta rules:
  1396     (asm_)(full_)simplify: simpset -> thm -> thm;
  1397 
  1398 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1399 logics (again);
  1400 
  1401 * added prems argument to simplification procedures;
  1402 
  1403 * HOL, FOL, ZF: added infix function `addsplits':
  1404   instead of `<simpset> setloop (split_tac <thms>)'
  1405   you can simply write `<simpset> addsplits <thms>'
  1406 
  1407 
  1408 *** Syntax ***
  1409 
  1410 * TYPE('a) syntax for type reflection terms;
  1411 
  1412 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1413 
  1414 * pretty printer: changed order of mixfix annotation preference (again!);
  1415 
  1416 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1417 
  1418 
  1419 *** HOL ***
  1420 
  1421 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1422   with `addloop' of the simplifier to faciliate case splitting in premises.
  1423 
  1424 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1425 
  1426 * HOL/Auth: new protocol proofs including some for the Internet
  1427   protocol TLS;
  1428 
  1429 * HOL/Map: new theory of `maps' a la VDM;
  1430 
  1431 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1432 cancelling out common nat summands from =, <, <= (in)equalities, or
  1433 differences; simplification procedures nat_cancel_factor for
  1434 cancelling common factor from =, <, <= (in)equalities over natural
  1435 sums; nat_cancel contains both kinds of procedures, it is installed by
  1436 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1437 
  1438 * HOL/simplifier: terms of the form
  1439   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1440   are rewritten to
  1441   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1442   and those of the form
  1443   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1444   are rewritten to
  1445   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1446 
  1447 * HOL/datatype
  1448   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1449 
  1450   P(t_case f1 ... fn x) =
  1451      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1452         ...
  1453        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1454      )
  1455 
  1456   and a theorem `split_t_case_asm' of the form
  1457 
  1458   P(t_case f1 ... fn x) =
  1459     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1460         ...
  1461        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1462      )
  1463   which can be added to a simpset via `addsplits'. The existing theorems
  1464   expand_list_case and expand_option_case have been renamed to
  1465   split_list_case and split_option_case.
  1466 
  1467 * HOL/Arithmetic:
  1468   - `pred n' is automatically converted to `n-1'.
  1469     Users are strongly encouraged not to use `pred' any longer,
  1470     because it will disappear altogether at some point.
  1471   - Users are strongly encouraged to write "0 < n" rather than
  1472     "n ~= 0". Theorems and proof tools have been modified towards this
  1473     `standard'.
  1474 
  1475 * HOL/Lists:
  1476   the function "set_of_list" has been renamed "set" (and its theorems too);
  1477   the function "nth" now takes its arguments in the reverse order and
  1478   has acquired the infix notation "!" as in "xs!n".
  1479 
  1480 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1481 
  1482 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1483   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1484 
  1485 * HOL/record: extensible records with schematic structural subtyping
  1486 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1487 still lacks various theorems and concrete record syntax;
  1488 
  1489 
  1490 *** HOLCF ***
  1491 
  1492 * removed "axioms" and "generated by" sections;
  1493 
  1494 * replaced "ops" section by extended "consts" section, which is capable of
  1495   handling the continuous function space "->" directly;
  1496 
  1497 * domain package:
  1498   . proves theorems immediately and stores them in the theory,
  1499   . creates hierachical name space,
  1500   . now uses normal mixfix annotations (instead of cinfix...),
  1501   . minor changes to some names and values (for consistency),
  1502   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1503   . separator between mutual domain defs: changed "," to "and",
  1504   . improved handling of sort constraints;  now they have to
  1505     appear on the left-hand side of the equations only;
  1506 
  1507 * fixed LAM <x,y,zs>.b syntax;
  1508 
  1509 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1510 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1511 
  1512 
  1513 *** FOL and ZF ***
  1514 
  1515 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1516   with `addloop' of the simplifier to faciliate case splitting in premises.
  1517 
  1518 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1519 in HOL, they strip ALL and --> from proved theorems;
  1520 
  1521 
  1522 
  1523 New in Isabelle94-8 (May 1997)
  1524 ------------------------------
  1525 
  1526 *** General Changes ***
  1527 
  1528 * new utilities to build / run / maintain Isabelle etc. (in parts
  1529 still somewhat experimental); old Makefiles etc. still functional;
  1530 
  1531 * new 'Isabelle System Manual';
  1532 
  1533 * INSTALL text, together with ./configure and ./build scripts;
  1534 
  1535 * reimplemented type inference for greater efficiency, better error
  1536 messages and clean internal interface;
  1537 
  1538 * prlim command for dealing with lots of subgoals (an easier way of
  1539 setting goals_limit);
  1540 
  1541 
  1542 *** Syntax ***
  1543 
  1544 * supports alternative (named) syntax tables (parser and pretty
  1545 printer); internal interface is provided by add_modesyntax(_i);
  1546 
  1547 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1548 be used in conjunction with the Isabelle symbol font; uses the
  1549 "symbols" syntax table;
  1550 
  1551 * added token_translation interface (may translate name tokens in
  1552 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1553 the current print_mode); IMPORTANT: user print translation functions
  1554 are responsible for marking newly introduced bounds
  1555 (Syntax.mark_boundT);
  1556 
  1557 * token translations for modes "xterm" and "xterm_color" that display
  1558 names in bold, underline etc. or colors (which requires a color
  1559 version of xterm);
  1560 
  1561 * infixes may now be declared with names independent of their syntax;
  1562 
  1563 * added typed_print_translation (like print_translation, but may
  1564 access type of constant);
  1565 
  1566 
  1567 *** Classical Reasoner ***
  1568 
  1569 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1570 some limitations.  Blast_tac...
  1571   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1572   + ignores elimination rules that don't have the correct format
  1573         (the conclusion MUST be a formula variable)
  1574   + ignores types, which can make HOL proofs fail
  1575   + rules must not require higher-order unification, e.g. apply_type in ZF
  1576     [message "Function Var's argument not a bound variable" relates to this]
  1577   + its proof strategy is more general but can actually be slower
  1578 
  1579 * substitution with equality assumptions no longer permutes other
  1580 assumptions;
  1581 
  1582 * minor changes in semantics of addafter (now called addaltern); renamed
  1583 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1584 (and access functions for it);
  1585 
  1586 * improved combination of classical reasoner and simplifier:
  1587   + functions for handling clasimpsets
  1588   + improvement of addss: now the simplifier is called _after_ the
  1589     safe steps.
  1590   + safe variant of addss called addSss: uses safe simplifications
  1591     _during_ the safe steps. It is more complete as it allows multiple
  1592     instantiations of unknowns (e.g. with slow_tac).
  1593 
  1594 *** Simplifier ***
  1595 
  1596 * added interface for simplification procedures (functions that
  1597 produce *proven* rewrite rules on the fly, depending on current
  1598 redex);
  1599 
  1600 * ordering on terms as parameter (used for ordered rewriting);
  1601 
  1602 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1603 
  1604 * the solver is now split into a safe and an unsafe part.
  1605 This should be invisible for the normal user, except that the
  1606 functions setsolver and addsolver have been renamed to setSolver and
  1607 addSolver; added safe_asm_full_simp_tac;
  1608 
  1609 
  1610 *** HOL ***
  1611 
  1612 * a generic induction tactic `induct_tac' which works for all datatypes and
  1613 also for type `nat';
  1614 
  1615 * a generic case distinction tactic `exhaust_tac' which works for all
  1616 datatypes and also for type `nat';
  1617 
  1618 * each datatype comes with a function `size';
  1619 
  1620 * patterns in case expressions allow tuple patterns as arguments to
  1621 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1622 
  1623 * primrec now also works with type nat;
  1624 
  1625 * recdef: a new declaration form, allows general recursive functions to be
  1626 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1627 
  1628 * the constant for negation has been renamed from "not" to "Not" to
  1629 harmonize with FOL, ZF, LK, etc.;
  1630 
  1631 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1632 infinite lists;
  1633 
  1634 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1635 
  1636 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1637 problems in commutative rings, using axiomatic type classes for + and *;
  1638 
  1639 * more examples in HOL/MiniML and HOL/Auth;
  1640 
  1641 * more default rewrite rules for quantifiers, union/intersection;
  1642 
  1643 * a new constant `arbitrary == @x.False';
  1644 
  1645 * HOLCF/IOA replaces old HOL/IOA;
  1646 
  1647 * HOLCF changes: derived all rules and arities
  1648   + axiomatic type classes instead of classes
  1649   + typedef instead of faking type definitions
  1650   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1651   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1652   + eliminated the types void, one, tr
  1653   + use unit lift and bool lift (with translations) instead of one and tr
  1654   + eliminated blift from Lift3.thy (use Def instead of blift)
  1655   all eliminated rules are derived as theorems --> no visible changes ;
  1656 
  1657 
  1658 *** ZF ***
  1659 
  1660 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1661 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1662 as ZF_cs addSIs [equalityI];
  1663 
  1664 
  1665 
  1666 New in Isabelle94-7 (November 96)
  1667 ---------------------------------
  1668 
  1669 * allowing negative levels (as offsets) in prlev and choplev;
  1670 
  1671 * super-linear speedup for large simplifications;
  1672 
  1673 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1674 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1675 FAIL); can suppress it using the command Delsimps (ex_simps @
  1676 all_simps); De Morgan laws are also now included, by default;
  1677 
  1678 * improved printing of ==>  :  ~:
  1679 
  1680 * new object-logic "Sequents" adds linear logic, while replacing LK
  1681 and Modal (thanks to Sara Kalvala);
  1682 
  1683 * HOL/Auth: correctness proofs for authentication protocols;
  1684 
  1685 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1686 examples on HOL/Auth);
  1687 
  1688 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1689 the rewriter and classical reasoner simultaneously;
  1690 
  1691 * function uresult no longer returns theorems in "standard" format;
  1692 regain previous version by: val uresult = standard o uresult;
  1693 
  1694 
  1695 
  1696 New in Isabelle94-6
  1697 -------------------
  1698 
  1699 * oracles -- these establish an interface between Isabelle and trusted
  1700 external reasoners, which may deliver results as theorems;
  1701 
  1702 * proof objects (in particular record all uses of oracles);
  1703 
  1704 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1705 
  1706 * "constdefs" section in theory files;
  1707 
  1708 * "primrec" section (HOL) no longer requires names;
  1709 
  1710 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1711 
  1712 
  1713 
  1714 New in Isabelle94-5
  1715 -------------------
  1716 
  1717 * reduced space requirements;
  1718 
  1719 * automatic HTML generation from theories;
  1720 
  1721 * theory files no longer require "..." (quotes) around most types;
  1722 
  1723 * new examples, including two proofs of the Church-Rosser theorem;
  1724 
  1725 * non-curried (1994) version of HOL is no longer distributed;
  1726 
  1727 
  1728 
  1729 New in Isabelle94-4
  1730 -------------------
  1731 
  1732 * greatly reduced space requirements;
  1733 
  1734 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1735 
  1736 * searchable theorem database (see the section "Retrieving theorems" on
  1737 page 8 of the Reference Manual);
  1738 
  1739 * new examples, including Grabczewski's monumental case study of the
  1740 Axiom of Choice;
  1741 
  1742 * The previous version of HOL renamed to Old_HOL;
  1743 
  1744 * The new version of HOL (previously called CHOL) uses a curried syntax
  1745 for functions.  Application looks like f a b instead of f(a,b);
  1746 
  1747 * Mutually recursive inductive definitions finally work in HOL;
  1748 
  1749 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1750 translates to the operator "split";
  1751 
  1752 
  1753 
  1754 New in Isabelle94-3
  1755 -------------------
  1756 
  1757 * new infix operator, addss, allowing the classical reasoner to
  1758 perform simplification at each step of its search.  Example:
  1759         fast_tac (cs addss ss)
  1760 
  1761 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1762 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1763 look like (a,b) instead of <a,b>;
  1764 
  1765 * PLEASE NOTE: CHOL will eventually replace HOL!
  1766 
  1767 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1768 It translates to the operator "split".  A new theory of integers is available;
  1769 
  1770 * In ZF, integer numerals now denote two's-complement binary integers.
  1771 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1772 
  1773 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1774 of the Axiom of Choice;
  1775 
  1776 
  1777 
  1778 New in Isabelle94-2
  1779 -------------------
  1780 
  1781 * Significantly faster resolution;
  1782 
  1783 * the different sections in a .thy file can now be mixed and repeated
  1784 freely;
  1785 
  1786 * Database of theorems for FOL, HOL and ZF.  New
  1787 commands including qed, qed_goal and bind_thm store theorems in the database.
  1788 
  1789 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1790 a given theory (thms_of), or find out what theory a theorem was proved in
  1791 (theory_of_thm);
  1792 
  1793 * Bugs fixed in the inductive definition and datatype packages;
  1794 
  1795 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1796 and HOL_dup_cs obsolete;
  1797 
  1798 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1799 have been removed;
  1800 
  1801 * Simpler definition of function space in ZF;
  1802 
  1803 * new results about cardinal and ordinal arithmetic in ZF;
  1804 
  1805 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1806 types;
  1807 
  1808 
  1809 $Id$