NEWS
author nipkow
Tue Jun 05 09:51:04 2001 +0200 (2001-06-05)
changeset 11361 879e53d92f51
parent 11314 f6eebbbed449
child 11397 0427e3c88062
permissions -rw-r--r--
*** empty log message ***
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 * print modes "type_brackets" and "no_type_brackets" control output of nested
     5 => (types); the default behaviour is "brackets";
     6 
     7 * Classical reasoner: renamed addaltern to addafter, addSaltern to addSafter
     8 
     9 * HOL: introduced f^n = f o ... o f
    10   WARNING: due to the limits of Isabelle's type classes, ^ on functions and
    11   relations has too general a domain, namely ('a * 'b)set and 'a => 'b.
    12   This means that it may be necessary to attach explicit type constraints.
    13 
    14 * HOL: added safe wrapper "split_conv_tac" to claset. EXISTING PROOFS MAY FAIL
    15 
    16 * HOL: made split_all_tac safe. EXISTING PROOFS MAY FAIL OR LOOP, so in this
    17   (rare) case use   delSWrapper "split_all_tac" addSbefore 
    18                     ("unsafe_split_all_tac", unsafe_split_all_tac)
    19 
    20 * ZF: the integer library now covers quotients and remainders, with many laws
    21 relating division to addition, multiplication, etc.;
    22 
    23 
    24 New in Isabelle99-2 (February 2001)
    25 -----------------------------------
    26 
    27 *** Overview of INCOMPATIBILITIES ***
    28 
    29 * HOL: please note that theories in the Library and elsewhere often use the
    30 new-style (Isar) format; to refer to their theorems in an ML script you must
    31 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
    32 
    33 * HOL: inductive package no longer splits induction rule aggressively,
    34 but only as far as specified by the introductions given; the old
    35 format may be recovered via ML function complete_split_rule or attribute
    36 'split_rule (complete)';
    37 
    38 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
    39 gfp_Tarski to gfp_unfold;
    40 
    41 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
    42 
    43 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
    44 relation); infix "^^" has been renamed "``"; infix "``" has been
    45 renamed "`"; "univalent" has been renamed "single_valued";
    46 
    47 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
    48 operation;
    49 
    50 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
    51 
    52 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
    53 
    54 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
    55 consequence, it is no longer monotonic wrt. the local goal context
    56 (which is now passed through the inductive cases);
    57 
    58 * Document preparation: renamed standard symbols \<ll> to \<lless> and
    59 \<gg> to \<ggreater>;
    60 
    61 
    62 *** Document preparation ***
    63 
    64 * \isabellestyle{NAME} selects version of Isabelle output (currently
    65 available: are "it" for near math-mode best-style output, "sl" for
    66 slanted text style, and "tt" for plain type-writer; if no
    67 \isabellestyle command is given, output is according to slanted
    68 type-writer);
    69 
    70 * support sub/super scripts (for single symbols only), input syntax is
    71 like this: "A\<^sup>*" or "A\<^sup>\<star>";
    72 
    73 * some more standard symbols; see Appendix A of the system manual for
    74 the complete list of symbols defined in isabellesym.sty;
    75 
    76 * improved isabelle style files; more abstract symbol implementation
    77 (should now use \isamath{...} and \isatext{...} in custom symbol
    78 definitions);
    79 
    80 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
    81 state; Note that presentation of goal states does not conform to
    82 actual human-readable proof documents.  Please do not include goal
    83 states into document output unless you really know what you are doing!
    84 
    85 * proper indentation of antiquoted output with proportional LaTeX
    86 fonts;
    87 
    88 * no_document ML operator temporarily disables LaTeX document
    89 generation;
    90 
    91 * isatool unsymbolize tunes sources for plain ASCII communication;
    92 
    93 
    94 *** Isar ***
    95 
    96 * Pure: Isar now suffers initial goal statements to contain unbound
    97 schematic variables (this does not conform to actual readable proof
    98 documents, due to unpredictable outcome and non-compositional proof
    99 checking); users who know what they are doing may use schematic goals
   100 for Prolog-style synthesis of proven results;
   101 
   102 * Pure: assumption method (an implicit finishing) now handles actual
   103 rules as well;
   104 
   105 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   106 initial goal, declare "that" only as Pure intro (only for single
   107 steps); the "that" rule assumption may now be involved in implicit
   108 finishing, thus ".." becomes a feasible for trivial obtains;
   109 
   110 * Pure: default proof step now includes 'intro_classes'; thus trivial
   111 instance proofs may be performed by "..";
   112 
   113 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   114 statements as well;
   115 
   116 * Pure: more robust selection of calculational rules;
   117 
   118 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   119 rule (as well as the assumption rule);
   120 
   121 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   122 lemmas, using the graph browser tool;
   123 
   124 * Pure: predict failure of "show" in interactive mode;
   125 
   126 * Pure: 'thms_containing' now takes actual terms as arguments;
   127 
   128 * HOL: improved method 'induct' --- now handles non-atomic goals
   129 (potential INCOMPATIBILITY); tuned error handling;
   130 
   131 * HOL: cases and induct rules now provide explicit hints about the
   132 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   133 any remaining facts are inserted into the goal verbatim;
   134 
   135 * HOL: local contexts (aka cases) may now contain term bindings as
   136 well; the 'cases' and 'induct' methods new provide a ?case binding for
   137 the result to be shown in each case;
   138 
   139 * HOL: added 'recdef_tc' command;
   140 
   141 * isatool convert assists in eliminating legacy ML scripts;
   142 
   143 
   144 *** HOL ***
   145 
   146 * HOL/Library: a collection of generic theories to be used together
   147 with main HOL; the theory loader path already includes this directory
   148 by default; the following existing theories have been moved here:
   149 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   150 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   151 
   152 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   153 modelling and verification task performed in Isabelle/HOL +
   154 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   155 
   156 * HOL/Algebra: special summation operator SUM no longer exists, it has
   157 been replaced by setsum; infix 'assoc' now has priority 50 (like
   158 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   159 'domain', this makes the theory consistent with mathematical
   160 literature;
   161 
   162 * HOL basics: added overloaded operations "inverse" and "divide"
   163 (infix "/"), syntax for generic "abs" operation, generic summation
   164 operator \<Sum>;
   165 
   166 * HOL/typedef: simplified package, provide more useful rules (see also
   167 HOL/subset.thy);
   168 
   169 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   170 now expressed as a proper nested rule (old-style tactic scripts may
   171 require atomize_strip_tac to cope with non-atomic premises);
   172 
   173 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   174 to "split_conv" (old name still available for compatibility);
   175 
   176 * HOL: improved concrete syntax for strings (e.g. allows translation
   177 rules with string literals);
   178 
   179 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   180 and Fleuriot's mechanization of analysis;
   181 
   182 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   183 
   184 
   185 *** CTT ***
   186 
   187 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   188 "lam" is displayed as TWO lambda-symbols
   189 
   190 * CTT: theory Main now available, containing everything (that is, Bool
   191 and Arith);
   192 
   193 
   194 *** General ***
   195 
   196 * Pure: the Simplifier has been implemented properly as a derived rule
   197 outside of the actual kernel (at last!); the overall performance
   198 penalty in practical applications is about 50%, while reliability of
   199 the Isabelle inference kernel has been greatly improved;
   200 
   201 * print modes "brackets" and "no_brackets" control output of nested =>
   202 (types) and ==> (props); the default behaviour is "brackets";
   203 
   204 * Provers: fast_tac (and friends) now handle actual object-logic rules
   205 as assumptions as well;
   206 
   207 * system: support Poly/ML 4.0;
   208 
   209 * system: isatool install handles KDE version 1 or 2;
   210 
   211 
   212 
   213 New in Isabelle99-1 (October 2000)
   214 ----------------------------------
   215 
   216 *** Overview of INCOMPATIBILITIES ***
   217 
   218 * HOL: simplification of natural numbers is much changed; to partly
   219 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   220 issue the following ML commands:
   221 
   222   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   223   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   224 
   225 * HOL: simplification no longer dives into case-expressions; this is
   226 controlled by "t.weak_case_cong" for each datatype t;
   227 
   228 * HOL: nat_less_induct renamed to less_induct;
   229 
   230 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   231 fixsome to patch .thy and .ML sources automatically;
   232 
   233   select_equality  -> some_equality
   234   select_eq_Ex     -> some_eq_ex
   235   selectI2EX       -> someI2_ex
   236   selectI2         -> someI2
   237   selectI          -> someI
   238   select1_equality -> some1_equality
   239   Eps_sym_eq       -> some_sym_eq_trivial
   240   Eps_eq           -> some_eq_trivial
   241 
   242 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   243 
   244 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   245 instead);
   246 
   247 * HOL: the recursion equations generated by 'recdef' are now called
   248 f.simps instead of f.rules;
   249 
   250 * HOL: qed_spec_mp now also handles bounded ALL as well;
   251 
   252 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   253 sometimes be needed;
   254 
   255 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   256 
   257 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   258 
   259 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   260 product is now "<*>" instead of "Times"; the lexicographic product is
   261 now "<*lex*>" instead of "**";
   262 
   263 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   264 of main HOL, but was unused); better use HOL's datatype package;
   265 
   266 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   267 the old syntax may be recovered as follows:
   268 
   269   syntax (symbols)
   270     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   271       (infixl "\\<oplus>" 100)
   272 
   273 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   274 
   275 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   276 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   277 internally;
   278 
   279 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   280 changed from A/r to A//r;
   281 
   282 * ZF: new treatment of arithmetic (nat & int) may break some old
   283 proofs;
   284 
   285 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   286 rulify -> rule_format, elimify -> elim_format, ...);
   287 
   288 * Isar/Provers: intro/elim/dest attributes changed; renamed
   289 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   290 should have to change intro!! to intro? only); replaced "delrule" by
   291 "rule del";
   292 
   293 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   294 
   295 * Provers: strengthened force_tac by using new first_best_tac;
   296 
   297 * LaTeX document preparation: several changes of isabelle.sty (see
   298 lib/texinputs);
   299 
   300 
   301 *** Document preparation ***
   302 
   303 * formal comments (text blocks etc.) in new-style theories may now
   304 contain antiquotations of thm/prop/term/typ/text to be presented
   305 according to latex print mode; concrete syntax is like this:
   306 @{term[show_types] "f(x) = a + x"};
   307 
   308 * isatool mkdir provides easy setup of Isabelle session directories,
   309 including proper document sources;
   310 
   311 * generated LaTeX sources are now deleted after successful run
   312 (isatool document -c); may retain a copy somewhere else via -D option
   313 of isatool usedir;
   314 
   315 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   316 style files, achieving self-contained LaTeX sources and simplifying
   317 LaTeX debugging;
   318 
   319 * old-style theories now produce (crude) LaTeX output as well;
   320 
   321 * browser info session directories are now self-contained (may be put
   322 on WWW server seperately); improved graphs of nested sessions; removed
   323 graph for 'all sessions';
   324 
   325 * several improvements in isabelle style files; \isabellestyle{it}
   326 produces fake math mode output; \isamarkupheader is now \section by
   327 default; see lib/texinputs/isabelle.sty etc.;
   328 
   329 
   330 *** Isar ***
   331 
   332 * Isar/Pure: local results and corresponding term bindings are now
   333 subject to Hindley-Milner polymorphism (similar to ML); this
   334 accommodates incremental type-inference very nicely;
   335 
   336 * Isar/Pure: new derived language element 'obtain' supports
   337 generalized existence reasoning;
   338 
   339 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   340 support accumulation of results, without applying any rules yet;
   341 useful to collect intermediate results without explicit name
   342 references, and for use with transitivity rules with more than 2
   343 premises;
   344 
   345 * Isar/Pure: scalable support for case-analysis type proofs: new
   346 'case' language element refers to local contexts symbolically, as
   347 produced by certain proof methods; internally, case names are attached
   348 to theorems as "tags";
   349 
   350 * Isar/Pure: theory command 'hide' removes declarations from
   351 class/type/const name spaces;
   352 
   353 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   354 indicate potential overloading;
   355 
   356 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   357 
   358 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   359 "{a,b,c}" instead of {a,b,c};
   360 
   361 * Isar/Pure now provides its own version of intro/elim/dest
   362 attributes; useful for building new logics, but beware of confusion
   363 with the version in Provers/classical;
   364 
   365 * Isar/Pure: the local context of (non-atomic) goals is provided via
   366 case name 'antecedent';
   367 
   368 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   369 to the current context is now done automatically);
   370 
   371 * Isar/Pure: theory command 'method_setup' provides a simple interface
   372 for definining proof methods in ML;
   373 
   374 * Isar/Provers: intro/elim/dest attributes changed; renamed
   375 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   376 most cases, one should have to change intro!! to intro? only);
   377 replaced "delrule" by "rule del";
   378 
   379 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   380 'symmetric' attribute (the latter supercedes [RS sym]);
   381 
   382 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   383 method modifier); 'simp' method: 'only:' modifier removes loopers as
   384 well (including splits);
   385 
   386 * Isar/Provers: Simplifier and Classical methods now support all kind
   387 of modifiers used in the past, including 'cong', 'iff', etc.
   388 
   389 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   390 of Simplifier and Classical reasoner);
   391 
   392 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   393 now support named cases; major packages (inductive, datatype, primrec,
   394 recdef) support case names and properly name parameters;
   395 
   396 * Isar/HOL: new transitivity rules for substitution in inequalities --
   397 monotonicity conditions are extracted to be proven at end of
   398 calculations;
   399 
   400 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   401 method anyway;
   402 
   403 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   404 split_if split_if_asm; datatype package provides theorems foo.splits =
   405 foo.split foo.split_asm for each datatype;
   406 
   407 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   408 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   409 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   410 use "(cases (simplified))" method in proper proof texts);
   411 
   412 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   413 
   414 * Isar: names of theorems etc. may be natural numbers as well;
   415 
   416 * Isar: 'pr' command: optional arguments for goals_limit and
   417 ProofContext.prems_limit; no longer prints theory contexts, but only
   418 proof states;
   419 
   420 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   421 additional print modes to be specified; e.g. "pr(latex)" will print
   422 proof state according to the Isabelle LaTeX style;
   423 
   424 * Isar: improved support for emulating tactic scripts, including proof
   425 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   426 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   427 (for HOL datatypes);
   428 
   429 * Isar: simplified (more robust) goal selection of proof methods: 1st
   430 goal, all goals, or explicit goal specifier (tactic emulation); thus
   431 'proof method scripts' have to be in depth-first order;
   432 
   433 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   434 
   435 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   436 should instead use individual commands for printing items
   437 (print_commands, print_methods etc.);
   438 
   439 * Isar: added 'nothing' --- the empty list of theorems;
   440 
   441 
   442 *** HOL ***
   443 
   444 * HOL/MicroJava: formalization of a fragment of Java, together with a
   445 corresponding virtual machine and a specification of its bytecode
   446 verifier and a lightweight bytecode verifier, including proofs of
   447 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   448 Cornelia Pusch (see also the homepage of project Bali at
   449 http://isabelle.in.tum.de/Bali/);
   450 
   451 * HOL/Algebra: new theory of rings and univariate polynomials, by
   452 Clemens Ballarin;
   453 
   454 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   455 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   456 Rasmussen;
   457 
   458 * HOL/Lattice: fundamental concepts of lattice theory and order
   459 structures, including duals, properties of bounds versus algebraic
   460 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   461 Theorem for complete lattices etc.; may also serve as a demonstration
   462 for abstract algebraic reasoning using axiomatic type classes, and
   463 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   464 
   465 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   466 von Oheimb;
   467 
   468 * HOL/IMPP: extension of IMP with local variables and mutually
   469 recursive procedures, by David von Oheimb;
   470 
   471 * HOL/Lambda: converted into new-style theory and document;
   472 
   473 * HOL/ex/Multiquote: example of multiple nested quotations and
   474 anti-quotations -- basically a generalized version of de-Bruijn
   475 representation; very useful in avoiding lifting of operations;
   476 
   477 * HOL/record: added general record equality rule to simpset; fixed
   478 select-update simplification procedure to handle extended records as
   479 well; admit "r" as field name;
   480 
   481 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   482 other numeric types and also as the identity of groups, rings, etc.;
   483 
   484 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   485 Types nat and int belong to this axclass;
   486 
   487 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   488    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   489    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   490   two terms #m*u and #n*u are replaced by #(m+n)*u
   491     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   492   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   493     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   494 
   495 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   496 powerful prover for predicate logic but knows nothing of clasets; see
   497 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   498 
   499 * HOL: new version of "case_tac" subsumes both boolean case split and
   500 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   501 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   502 
   503 * HOL: simplification no longer dives into case-expressions: only the
   504 selector expression is simplified, but not the remaining arms; to
   505 enable full simplification of case-expressions for datatype t, you may
   506 remove t.weak_case_cong from the simpset, either globally (Delcongs
   507 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   508 
   509 * HOL/recdef: the recursion equations generated by 'recdef' for
   510 function 'f' are now called f.simps instead of f.rules; if all
   511 termination conditions are proved automatically, these simplification
   512 rules are added to the simpset, as in primrec; rules may be named
   513 individually as well, resulting in a separate list of theorems for
   514 each equation;
   515 
   516 * HOL/While is a new theory that provides a while-combinator. It
   517 permits the definition of tail-recursive functions without the
   518 provision of a termination measure. The latter is necessary once the
   519 invariant proof rule for while is applied.
   520 
   521 * HOL: new (overloaded) notation for the set of elements below/above
   522 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   523 
   524 * HOL: theorems impI, allI, ballI bound as "strip";
   525 
   526 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   527 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   528 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   529 
   530 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   531 
   532 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   533 main HOL, but was unused);
   534 
   535 * HOL: fewer consts declared as global (e.g. have to refer to
   536 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   537 
   538 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   539 in case of overlap with user translations (e.g. judgements over
   540 tuples); (note that the underlying logical represenation is still
   541 bogus);
   542 
   543 
   544 *** ZF ***
   545 
   546 * ZF: simplification automatically cancels common terms in arithmetic
   547 expressions over nat and int;
   548 
   549 * ZF: new treatment of nat to minimize type-checking: all operators
   550 coerce their operands to a natural number using the function natify,
   551 making the algebraic laws unconditional;
   552 
   553 * ZF: as above, for int: operators coerce their operands to an integer
   554 using the function intify;
   555 
   556 * ZF: the integer library now contains many of the usual laws for the
   557 orderings, including $<=, and monotonicity laws for $+ and $*;
   558 
   559 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   560 simplification;
   561 
   562 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   563 to the simplifier and classical reasoner simultaneously;
   564 
   565 
   566 *** General ***
   567 
   568 * Provers: blast_tac now handles actual object-logic rules as
   569 assumptions; note that auto_tac uses blast_tac internally as well;
   570 
   571 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   572 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   573 
   574 * Provers: delrules now handles destruct rules as well (no longer need
   575 explicit make_elim);
   576 
   577 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   578   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   579 use instead the strong form,
   580   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   581 in HOL, FOL and ZF the function cla_make_elim will create such rules
   582 from destruct-rules;
   583 
   584 * Provers: Simplifier.easy_setup provides a fast path to basic
   585 Simplifier setup for new object-logics;
   586 
   587 * Pure: AST translation rules no longer require constant head on LHS;
   588 
   589 * Pure: improved name spaces: ambiguous output is qualified; support
   590 for hiding of names;
   591 
   592 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   593 XSYMBOL_HOME; no longer need to do manual configuration in most
   594 situations;
   595 
   596 * system: compression of ML heaps images may now be controlled via -c
   597 option of isabelle and isatool usedir (currently only observed by
   598 Poly/ML);
   599 
   600 * system: isatool installfonts may handle X-Symbol fonts as well (very
   601 useful for remote X11);
   602 
   603 * system: provide TAGS file for Isabelle sources;
   604 
   605 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   606 order;
   607 
   608 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   609 timing flag supersedes proof_timing and Toplevel.trace;
   610 
   611 * ML: new combinators |>> and |>>> for incremental transformations
   612 with secondary results (e.g. certain theory extensions):
   613 
   614 * ML: PureThy.add_defs gets additional argument to indicate potential
   615 overloading (usually false);
   616 
   617 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   618 results;
   619 
   620 
   621 
   622 New in Isabelle99 (October 1999)
   623 --------------------------------
   624 
   625 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   626 
   627 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   628 are no longer simplified.  (This allows the simplifier to unfold recursive
   629 functional programs.)  To restore the old behaviour, declare
   630 
   631     Delcongs [if_weak_cong];
   632 
   633 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   634 complement;
   635 
   636 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   637 
   638 * HOL/datatype: mutual_induct_tac no longer exists --
   639   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   640 
   641 * HOL/typedef: fixed type inference for representing set; type
   642 arguments now have to occur explicitly on the rhs as type constraints;
   643 
   644 * ZF: The con_defs part of an inductive definition may no longer refer
   645 to constants declared in the same theory;
   646 
   647 * HOL, ZF: the function mk_cases, generated by the inductive
   648 definition package, has lost an argument.  To simplify its result, it
   649 uses the default simpset instead of a supplied list of theorems.
   650 
   651 * HOL/List: the constructors of type list are now Nil and Cons;
   652 
   653 * Simplifier: the type of the infix ML functions
   654         setSSolver addSSolver setSolver addSolver
   655 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   656 for packaging solvers. A solver is created via
   657         mk_solver: string -> (thm list -> int -> tactic) -> solver
   658 where the string argument is only a comment.
   659 
   660 
   661 *** Proof tools ***
   662 
   663 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   664 decision procedure for linear arithmetic. Currently it is used for
   665 types `nat', `int', and `real' in HOL (see below); it can, should and
   666 will be instantiated for other types and logics as well.
   667 
   668 * The simplifier now accepts rewrite rules with flexible heads, eg
   669      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   670   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   671   matching.
   672 
   673 
   674 *** General ***
   675 
   676 * New Isabelle/Isar subsystem provides an alternative to traditional
   677 tactical theorem proving; together with the ProofGeneral/isar user
   678 interface it offers an interactive environment for developing human
   679 readable proof documents (Isar == Intelligible semi-automated
   680 reasoning); for further information see isatool doc isar-ref,
   681 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   682 
   683 * improved and simplified presentation of theories: better HTML markup
   684 (including colors), graph views in several sizes; isatool usedir now
   685 provides a proper interface for user theories (via -P option); actual
   686 document preparation based on (PDF)LaTeX is available as well (for
   687 new-style theories only); see isatool doc system for more information;
   688 
   689 * native support for Proof General, both for classic Isabelle and
   690 Isabelle/Isar;
   691 
   692 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   693 using the graph browser tool;
   694 
   695 * Isabelle manuals now also available as PDF;
   696 
   697 * theory loader rewritten from scratch (may not be fully
   698 bug-compatible); old loadpath variable has been replaced by show_path,
   699 add_path, del_path, reset_path functions; new operations such as
   700 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   701 isatool doc ref);
   702 
   703 * improved isatool install: option -k creates KDE application icon,
   704 option -p DIR installs standalone binaries;
   705 
   706 * added ML_PLATFORM setting (useful for cross-platform installations);
   707 more robust handling of platform specific ML images for SML/NJ;
   708 
   709 * the settings environment is now statically scoped, i.e. it is never
   710 created again in sub-processes invoked from isabelle, isatool, or
   711 Isabelle;
   712 
   713 * path element specification '~~' refers to '$ISABELLE_HOME';
   714 
   715 * in locales, the "assumes" and "defines" parts may be omitted if
   716 empty;
   717 
   718 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   719 long arrows);
   720 
   721 * new print_mode "HTML";
   722 
   723 * new flag show_tags controls display of tags of theorems (which are
   724 basically just comments that may be attached by some tools);
   725 
   726 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   727 mode and goal output format:
   728 
   729 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   730 244c244
   731 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   732 ---
   733 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   734 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   735 181c181
   736 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   737 ---
   738 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   739 
   740 * function bind_thms stores lists of theorems (cf. bind_thm);
   741 
   742 * new shorthand tactics ftac, eatac, datac, fatac;
   743 
   744 * qed (and friends) now accept "" as result name; in that case the
   745 theorem is not stored, but proper checks and presentation of the
   746 result still apply;
   747 
   748 * theorem database now also indexes constants "Trueprop", "all",
   749 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   750 
   751 
   752 *** HOL ***
   753 
   754 ** HOL arithmetic **
   755 
   756 * There are now decision procedures for linear arithmetic over nat and
   757 int:
   758 
   759 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   760 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   761 are treated as atomic; subformulae not involving type `nat' or `int'
   762 are ignored; quantified subformulae are ignored unless they are
   763 positive universal or negative existential. The tactic has to be
   764 invoked by hand and can be a little bit slow. In particular, the
   765 running time is exponential in the number of occurrences of `min' and
   766 `max', and `-' on `nat'.
   767 
   768 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   769 (negated) (in)equalities among the premises and the conclusion into
   770 account (i.e. no compound formulae) and does not know about `min' and
   771 `max', and `-' on `nat'. It is fast and is used automatically by the
   772 simplifier.
   773 
   774 NB: At the moment, these decision procedures do not cope with mixed
   775 nat/int formulae where the two parts interact, such as `m < n ==>
   776 int(m) < int(n)'.
   777 
   778 * HOL/Numeral provides a generic theory of numerals (encoded
   779 efficiently as bit strings); setup for types nat/int/real is in place;
   780 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   781 int, existing theories and proof scripts may require a few additional
   782 type constraints;
   783 
   784 * integer division and remainder can now be performed on constant
   785 arguments;
   786 
   787 * many properties of integer multiplication, division and remainder
   788 are now available;
   789 
   790 * An interface to the Stanford Validity Checker (SVC) is available through the
   791 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   792 are proved automatically.  SVC must be installed separately, and its results
   793 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   794 invocation of the underlying oracle).  For SVC see
   795   http://verify.stanford.edu/SVC
   796 
   797 * IsaMakefile: the HOL-Real target now builds an actual image;
   798 
   799 
   800 ** HOL misc **
   801 
   802 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   803 (in Isabelle/Isar) -- by Gertrud Bauer;
   804 
   805 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   806 analysis for assembly languages with subtypes;
   807 
   808 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   809 -- avoids syntactic ambiguities and treats state, transition, and
   810 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   811 changed syntax and (many) tactics;
   812 
   813 * HOL/inductive: Now also handles more general introduction rules such
   814   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   815   theorems are now maintained within the theory (maintained via the
   816   "mono" attribute);
   817 
   818 * HOL/datatype: Now also handles arbitrarily branching datatypes
   819   (using function types) such as
   820 
   821   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   822 
   823 * HOL/record: record_simproc (part of the default simpset) takes care
   824 of selectors applied to updated records; record_split_tac is no longer
   825 part of the default claset; update_defs may now be removed from the
   826 simpset in many cases; COMPATIBILITY: old behavior achieved by
   827 
   828   claset_ref () := claset() addSWrapper record_split_wrapper;
   829   Delsimprocs [record_simproc]
   830 
   831 * HOL/typedef: fixed type inference for representing set; type
   832 arguments now have to occur explicitly on the rhs as type constraints;
   833 
   834 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   835 names rather than an ML expression;
   836 
   837 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   838 supplied later.  Program schemes can be defined, such as
   839     "While B C s = (if B s then While B C (C s) else s)"
   840 where the well-founded relation can be chosen after B and C have been given.
   841 
   842 * HOL/List: the constructors of type list are now Nil and Cons;
   843 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   844 course, ML tools referring to List.list.op # etc. have to be adapted;
   845 
   846 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   847 disabled by default; run isabelle with option -m HOL to get back to
   848 the original Gordon/HOL-style output;
   849 
   850 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   851 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   852 
   853 * HOL basic syntax simplified (more orthogonal): all variants of
   854 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   855 Eps operator is provided as well: "SOME x. P[x]";
   856 
   857 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   858 
   859 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   860 thus available for user theories;
   861 
   862 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   863 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   864 time;
   865 
   866 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   867 several times and then mp;
   868 
   869 
   870 *** LK ***
   871 
   872 * the notation <<...>> is now available as a notation for sequences of
   873 formulas;
   874 
   875 * the simplifier is now installed
   876 
   877 * the axiom system has been generalized (thanks to Soren Heilmann)
   878 
   879 * the classical reasoner now has a default rule database
   880 
   881 
   882 *** ZF ***
   883 
   884 * new primrec section allows primitive recursive functions to be given
   885 directly (as in HOL) over datatypes and the natural numbers;
   886 
   887 * new tactics induct_tac and exhaust_tac for induction (or case
   888 analysis) over datatypes and the natural numbers;
   889 
   890 * the datatype declaration of type T now defines the recursor T_rec;
   891 
   892 * simplification automatically does freeness reasoning for datatype
   893 constructors;
   894 
   895 * automatic type-inference, with AddTCs command to insert new
   896 type-checking rules;
   897 
   898 * datatype introduction rules are now added as Safe Introduction rules
   899 to the claset;
   900 
   901 * the syntax "if P then x else y" is now available in addition to
   902 if(P,x,y);
   903 
   904 
   905 *** Internal programming interfaces ***
   906 
   907 * tuned simplifier trace output; new flag debug_simp;
   908 
   909 * structures Vartab / Termtab (instances of TableFun) offer efficient
   910 tables indexed by indexname_ord / term_ord (compatible with aconv);
   911 
   912 * AxClass.axclass_tac lost the theory argument;
   913 
   914 * tuned current_goals_markers semantics: begin / end goal avoids
   915 printing empty lines;
   916 
   917 * removed prs and prs_fn hook, which was broken because it did not
   918 include \n in its semantics, forcing writeln to add one
   919 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   920 string -> unit if you really want to output text without newline;
   921 
   922 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   923 plain output, interface builders may have to enable 'isabelle_font'
   924 mode to get Isabelle font glyphs as before;
   925 
   926 * refined token_translation interface; INCOMPATIBILITY: output length
   927 now of type real instead of int;
   928 
   929 * theory loader actions may be traced via new ThyInfo.add_hook
   930 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   931 your own database of information attached to *whole* theories -- as
   932 opposed to intra-theory data slots offered via TheoryDataFun;
   933 
   934 * proper handling of dangling sort hypotheses (at last!);
   935 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   936 extra sort hypotheses that can be witnessed from the type signature;
   937 the force_strip_shyps flag is gone, any remaining shyps are simply
   938 left in the theorem (with a warning issued by strip_shyps_warning);
   939 
   940 
   941 
   942 New in Isabelle98-1 (October 1998)
   943 ----------------------------------
   944 
   945 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   946 
   947 * several changes of automated proof tools;
   948 
   949 * HOL: major changes to the inductive and datatype packages, including
   950 some minor incompatibilities of theory syntax;
   951 
   952 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   953 called `inj_on';
   954 
   955 * HOL: removed duplicate thms in Arith:
   956   less_imp_add_less  should be replaced by  trans_less_add1
   957   le_imp_add_le      should be replaced by  trans_le_add1
   958 
   959 * HOL: unary minus is now overloaded (new type constraints may be
   960 required);
   961 
   962 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   963 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   964 now taken as an integer constant.
   965 
   966 * Pure: ML function 'theory_of' renamed to 'theory';
   967 
   968 
   969 *** Proof tools ***
   970 
   971 * Simplifier:
   972   1. Asm_full_simp_tac is now more aggressive.
   973      1. It will sometimes reorient premises if that increases their power to
   974         simplify.
   975      2. It does no longer proceed strictly from left to right but may also
   976         rotate premises to achieve further simplification.
   977      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   978      old Asm_full_simp_tac in that it does not rotate premises.
   979   2. The simplifier now knows a little bit about nat-arithmetic.
   980 
   981 * Classical reasoner: wrapper mechanism for the classical reasoner now
   982 allows for selected deletion of wrappers, by introduction of names for
   983 wrapper functionals.  This implies that addbefore, addSbefore,
   984 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   985 and that adding two tactics with the same name overwrites the first
   986 one (emitting a warning).
   987   type wrapper = (int -> tactic) -> (int -> tactic)
   988   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   989   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   990   delWrapper, delSWrapper: claset *  string            -> claset
   991   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   992 
   993 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   994 semantics; addbefore now affects only the unsafe part of step_tac
   995 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   996 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   997 by Force_tac;
   998 
   999 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1000 compWrapper; added safe wrapper (and access functions for it);
  1001 
  1002 * HOL/split_all_tac is now much faster and fails if there is nothing
  1003 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1004 and the names of the automatically generated variables have changed.
  1005 split_all_tac has moved within claset() from unsafe wrappers to safe
  1006 wrappers, which means that !!-bound variables are split much more
  1007 aggressively, and safe_tac and clarify_tac now split such variables.
  1008 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1009 Note: the same holds for record_split_tac, which does the job of
  1010 split_all_tac for record fields.
  1011 
  1012 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1013 permanently to the default simpset using Addsplits just like
  1014 Addsimps. They can be removed via Delsplits just like
  1015 Delsimps. Lower-case versions are also available.
  1016 
  1017 * HOL/Simplifier: The rule split_if is now part of the default
  1018 simpset. This means that the simplifier will eliminate all occurrences
  1019 of if-then-else in the conclusion of a goal. To prevent this, you can
  1020 either remove split_if completely from the default simpset by
  1021 `Delsplits [split_if]' or remove it in a specific call of the
  1022 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1023 other case splitting rules to/from the default simpset: every datatype
  1024 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1025 t is the name of the datatype).
  1026 
  1027 * Classical reasoner / Simplifier combination: new force_tac (and
  1028 derivatives Force_tac, force) combines rewriting and classical
  1029 reasoning (and whatever other tools) similarly to auto_tac, but is
  1030 aimed to solve the given subgoal completely.
  1031 
  1032 
  1033 *** General ***
  1034 
  1035 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1036 and `goalw': the theory is no longer needed as an explicit argument -
  1037 the current theory context is used; assumptions are no longer returned
  1038 at the ML-level unless one of them starts with ==> or !!; it is
  1039 recommended to convert to these new commands using isatool fixgoal
  1040 (backup your sources first!);
  1041 
  1042 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1043 the current theory context, and 'theory' to lookup stored theories;
  1044 
  1045 * new theory section 'locale' for declaring constants, assumptions and
  1046 definitions that have local scope;
  1047 
  1048 * new theory section 'nonterminals' for purely syntactic types;
  1049 
  1050 * new theory section 'setup' for generic ML setup functions
  1051 (e.g. package initialization);
  1052 
  1053 * the distribution now includes Isabelle icons: see
  1054 lib/logo/isabelle-{small,tiny}.xpm;
  1055 
  1056 * isatool install - install binaries with absolute references to
  1057 ISABELLE_HOME/bin;
  1058 
  1059 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1060 
  1061 * print mode 'emacs' reserved for Isamode;
  1062 
  1063 * support multiple print (ast) translations per constant name;
  1064 
  1065 * theorems involving oracles are now printed with a suffixed [!];
  1066 
  1067 
  1068 *** HOL ***
  1069 
  1070 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1071 
  1072 * HOL/inductive package reorganized and improved: now supports mutual
  1073 definitions such as
  1074 
  1075   inductive EVEN ODD
  1076     intrs
  1077       null "0 : EVEN"
  1078       oddI "n : EVEN ==> Suc n : ODD"
  1079       evenI "n : ODD ==> Suc n : EVEN"
  1080 
  1081 new theorem list "elims" contains an elimination rule for each of the
  1082 recursive sets; inductive definitions now handle disjunctive premises
  1083 correctly (also ZF);
  1084 
  1085 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1086 "mutual_induct" no longer exists - the induction rule is always
  1087 contained in "induct";
  1088 
  1089 
  1090 * HOL/datatype package re-implemented and greatly improved: now
  1091 supports mutually recursive datatypes such as
  1092 
  1093   datatype
  1094     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1095             | SUM ('a aexp) ('a aexp)
  1096             | DIFF ('a aexp) ('a aexp)
  1097             | NUM 'a
  1098   and
  1099     'a bexp = LESS ('a aexp) ('a aexp)
  1100             | AND ('a bexp) ('a bexp)
  1101             | OR ('a bexp) ('a bexp)
  1102 
  1103 as well as indirectly recursive datatypes such as
  1104 
  1105   datatype
  1106     ('a, 'b) term = Var 'a
  1107                   | App 'b ((('a, 'b) term) list)
  1108 
  1109 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1110 induction on mutually / indirectly recursive datatypes.
  1111 
  1112 Primrec equations are now stored in theory and can be accessed via
  1113 <function_name>.simps.
  1114 
  1115 INCOMPATIBILITIES:
  1116 
  1117   - Theories using datatypes must now have theory Datatype as an
  1118     ancestor.
  1119   - The specific <typename>.induct_tac no longer exists - use the
  1120     generic induct_tac instead.
  1121   - natE has been renamed to nat.exhaust - use exhaust_tac
  1122     instead of res_inst_tac ... natE. Note that the variable
  1123     names in nat.exhaust differ from the names in natE, this
  1124     may cause some "fragile" proofs to fail.
  1125   - The theorems split_<typename>_case and split_<typename>_case_asm
  1126     have been renamed to <typename>.split and <typename>.split_asm.
  1127   - Since default sorts of type variables are now handled correctly,
  1128     some datatype definitions may have to be annotated with explicit
  1129     sort constraints.
  1130   - Primrec definitions no longer require function name and type
  1131     of recursive argument.
  1132 
  1133 Consider using isatool fixdatatype to adapt your theories and proof
  1134 scripts to the new package (backup your sources first!).
  1135 
  1136 
  1137 * HOL/record package: considerably improved implementation; now
  1138 includes concrete syntax for record types, terms, updates; theorems
  1139 for surjective pairing and splitting !!-bound record variables; proof
  1140 support is as follows:
  1141 
  1142   1) standard conversions (selectors or updates applied to record
  1143 constructor terms) are part of the standard simpset;
  1144 
  1145   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1146 made part of standard simpset and claset via addIffs;
  1147 
  1148   3) a tactic for record field splitting (record_split_tac) is part of
  1149 the standard claset (addSWrapper);
  1150 
  1151 To get a better idea about these rules you may retrieve them via
  1152 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1153 the name of your record type.
  1154 
  1155 The split tactic 3) conceptually simplifies by the following rule:
  1156 
  1157   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1158 
  1159 Thus any record variable that is bound by meta-all will automatically
  1160 blow up into some record constructor term, consequently the
  1161 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1162 solve record problems automatically.
  1163 
  1164 
  1165 * reorganized the main HOL image: HOL/Integ and String loaded by
  1166 default; theory Main includes everything;
  1167 
  1168 * automatic simplification of integer sums and comparisons, using cancellation;
  1169 
  1170 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1171 
  1172 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1173 
  1174 * many new identities for unions, intersections, set difference, etc.;
  1175 
  1176 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1177 called split_if, split_split, split_sum_case and split_nat_case (to go
  1178 with add/delsplits);
  1179 
  1180 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1181 (?x::unit) = (); this is made part of the default simpset, which COULD
  1182 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1183 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1184 unit_abs_eta_conv is added in order to counter the effect of
  1185 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1186 %u.f();
  1187 
  1188 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1189 makes more sense);
  1190 
  1191 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1192   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1193   disjointness reasoning but breaking a few old proofs.
  1194 
  1195 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1196 to 'converse' from 'inverse' (for compatibility with ZF and some
  1197 literature);
  1198 
  1199 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1200 the well-founded relation;
  1201 
  1202 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1203     Compl A.  The "Compl" syntax remains available as input syntax for this
  1204     release ONLY.
  1205 
  1206 * HOL/Update: new theory of function updates:
  1207     f(a:=b) == %x. if x=a then b else f x
  1208 may also be iterated as in f(a:=b,c:=d,...);
  1209 
  1210 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1211 
  1212 * HOL/List:
  1213   - new function list_update written xs[i:=v] that updates the i-th
  1214     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1215   - new function `upt' written [i..j(] which generates the list
  1216     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1217     bound write [i..j], which is a shorthand for [i..j+1(].
  1218   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1219 
  1220 * HOL/Arith:
  1221   - removed 'pred' (predecessor) function;
  1222   - generalized some theorems about n-1;
  1223   - many new laws about "div" and "mod";
  1224   - new laws about greatest common divisors (see theory ex/Primes);
  1225 
  1226 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1227 instead of "inverse";
  1228 
  1229 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1230   of the multiset ordering;
  1231 
  1232 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1233   (not included by default);
  1234 
  1235 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1236 
  1237 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1238   programs, i.e. different program variables may have different types.
  1239 
  1240 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1241   [previously, this check worked only if the rewrite rule was unconditional]
  1242   Now rew can involve either definitions or equalities (either == or =).
  1243 
  1244 
  1245 *** ZF ***
  1246 
  1247 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1248   only the theorems proved on ZF.ML;
  1249 
  1250 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1251   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1252   disjointness reasoning but breaking a few old proofs.
  1253 
  1254 * ZF/Update: new theory of function updates
  1255     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1256   may also be iterated as in f(a:=b,c:=d,...);
  1257 
  1258 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1259 
  1260 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1261   [previously, this check worked only if the rewrite rule was unconditional]
  1262   Now rew can involve either definitions or equalities (either == or =).
  1263 
  1264 * case_tac provided for compatibility with HOL
  1265     (like the old excluded_middle_tac, but with subgoals swapped)
  1266 
  1267 
  1268 *** Internal programming interfaces ***
  1269 
  1270 * Pure: several new basic modules made available for general use, see
  1271 also src/Pure/README;
  1272 
  1273 * improved the theory data mechanism to support encapsulation (data
  1274 kind name replaced by private Object.kind, acting as authorization
  1275 key); new type-safe user interface via functor TheoryDataFun; generic
  1276 print_data function becomes basically useless;
  1277 
  1278 * removed global_names compatibility flag -- all theory declarations
  1279 are qualified by default;
  1280 
  1281 * module Pure/Syntax now offers quote / antiquote translation
  1282 functions (useful for Hoare logic etc. with implicit dependencies);
  1283 see HOL/ex/Antiquote for an example use;
  1284 
  1285 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1286 cterm -> thm;
  1287 
  1288 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1289 subgoal;
  1290 
  1291 * Display.print_goals function moved to Locale.print_goals;
  1292 
  1293 * standard print function for goals supports current_goals_markers
  1294 variable for marking begin of proof, end of proof, start of goal; the
  1295 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1296 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1297 for example;
  1298 
  1299 
  1300 
  1301 New in Isabelle98 (January 1998)
  1302 --------------------------------
  1303 
  1304 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1305 
  1306 * changed lexical syntax of terms / types: dots made part of long
  1307 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1308 
  1309 * simpset (and claset) reference variable replaced by functions
  1310 simpset / simpset_ref;
  1311 
  1312 * no longer supports theory aliases (via merge) and non-trivial
  1313 implicit merge of thms' signatures;
  1314 
  1315 * most internal names of constants changed due to qualified names;
  1316 
  1317 * changed Pure/Sequence interface (see Pure/seq.ML);
  1318 
  1319 
  1320 *** General Changes ***
  1321 
  1322 * hierachically structured name spaces (for consts, types, axms, thms
  1323 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1324 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1325 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1326 long_names for fully qualified output names; NOTE: ML programs
  1327 (special tactics, packages etc.) referring to internal names may have
  1328 to be adapted to cope with fully qualified names; in case of severe
  1329 backward campatibility problems try setting 'global_names' at compile
  1330 time to have enrything declared within a flat name space; one may also
  1331 fine tune name declarations in theories via the 'global' and 'local'
  1332 section;
  1333 
  1334 * reimplemented the implicit simpset and claset using the new anytype
  1335 data filed in signatures; references simpset:simpset ref etc. are
  1336 replaced by functions simpset:unit->simpset and
  1337 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1338 to patch your ML files accordingly;
  1339 
  1340 * HTML output now includes theory graph data for display with Java
  1341 applet or isatool browser; data generated automatically via isatool
  1342 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1343 
  1344 * defs may now be conditional; improved rewrite_goals_tac to handle
  1345 conditional equations;
  1346 
  1347 * defs now admits additional type arguments, using TYPE('a) syntax;
  1348 
  1349 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1350 creates a new theory node; implicit merge of thms' signatures is
  1351 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1352 transfer:theory->thm->thm in (rare) cases;
  1353 
  1354 * improved handling of draft signatures / theories; draft thms (and
  1355 ctyps, cterms) are automatically promoted to real ones;
  1356 
  1357 * slightly changed interfaces for oracles: admit many per theory, named
  1358 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1359 
  1360 * print_goals: optional output of const types (set show_consts and
  1361 show_types);
  1362 
  1363 * improved output of warnings (###) and errors (***);
  1364 
  1365 * subgoal_tac displays a warning if the new subgoal has type variables;
  1366 
  1367 * removed old README and Makefiles;
  1368 
  1369 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1370 
  1371 * removed obsolete init_pps and init_database;
  1372 
  1373 * deleted the obsolete tactical STATE, which was declared by
  1374     fun STATE tacfun st = tacfun st st;
  1375 
  1376 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1377 (which abbreviates $HOME);
  1378 
  1379 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1380 use isatool fixseq to adapt your ML programs (this works for fully
  1381 qualified references to the Sequence structure only!);
  1382 
  1383 * use_thy no longer requires writable current directory; it always
  1384 reloads .ML *and* .thy file, if either one is out of date;
  1385 
  1386 
  1387 *** Classical Reasoner ***
  1388 
  1389 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1390 tactics that use classical reasoning to simplify a subgoal without
  1391 splitting it into several subgoals;
  1392 
  1393 * Safe_tac: like safe_tac but uses the default claset;
  1394 
  1395 
  1396 *** Simplifier ***
  1397 
  1398 * added simplification meta rules:
  1399     (asm_)(full_)simplify: simpset -> thm -> thm;
  1400 
  1401 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1402 logics (again);
  1403 
  1404 * added prems argument to simplification procedures;
  1405 
  1406 * HOL, FOL, ZF: added infix function `addsplits':
  1407   instead of `<simpset> setloop (split_tac <thms>)'
  1408   you can simply write `<simpset> addsplits <thms>'
  1409 
  1410 
  1411 *** Syntax ***
  1412 
  1413 * TYPE('a) syntax for type reflection terms;
  1414 
  1415 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1416 
  1417 * pretty printer: changed order of mixfix annotation preference (again!);
  1418 
  1419 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1420 
  1421 
  1422 *** HOL ***
  1423 
  1424 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1425   with `addloop' of the simplifier to faciliate case splitting in premises.
  1426 
  1427 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1428 
  1429 * HOL/Auth: new protocol proofs including some for the Internet
  1430   protocol TLS;
  1431 
  1432 * HOL/Map: new theory of `maps' a la VDM;
  1433 
  1434 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1435 cancelling out common nat summands from =, <, <= (in)equalities, or
  1436 differences; simplification procedures nat_cancel_factor for
  1437 cancelling common factor from =, <, <= (in)equalities over natural
  1438 sums; nat_cancel contains both kinds of procedures, it is installed by
  1439 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1440 
  1441 * HOL/simplifier: terms of the form
  1442   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1443   are rewritten to
  1444   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1445   and those of the form
  1446   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1447   are rewritten to
  1448   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1449 
  1450 * HOL/datatype
  1451   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1452 
  1453   P(t_case f1 ... fn x) =
  1454      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1455         ...
  1456        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1457      )
  1458 
  1459   and a theorem `split_t_case_asm' of the form
  1460 
  1461   P(t_case f1 ... fn x) =
  1462     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1463         ...
  1464        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1465      )
  1466   which can be added to a simpset via `addsplits'. The existing theorems
  1467   expand_list_case and expand_option_case have been renamed to
  1468   split_list_case and split_option_case.
  1469 
  1470 * HOL/Arithmetic:
  1471   - `pred n' is automatically converted to `n-1'.
  1472     Users are strongly encouraged not to use `pred' any longer,
  1473     because it will disappear altogether at some point.
  1474   - Users are strongly encouraged to write "0 < n" rather than
  1475     "n ~= 0". Theorems and proof tools have been modified towards this
  1476     `standard'.
  1477 
  1478 * HOL/Lists:
  1479   the function "set_of_list" has been renamed "set" (and its theorems too);
  1480   the function "nth" now takes its arguments in the reverse order and
  1481   has acquired the infix notation "!" as in "xs!n".
  1482 
  1483 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1484 
  1485 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1486   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1487 
  1488 * HOL/record: extensible records with schematic structural subtyping
  1489 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1490 still lacks various theorems and concrete record syntax;
  1491 
  1492 
  1493 *** HOLCF ***
  1494 
  1495 * removed "axioms" and "generated by" sections;
  1496 
  1497 * replaced "ops" section by extended "consts" section, which is capable of
  1498   handling the continuous function space "->" directly;
  1499 
  1500 * domain package:
  1501   . proves theorems immediately and stores them in the theory,
  1502   . creates hierachical name space,
  1503   . now uses normal mixfix annotations (instead of cinfix...),
  1504   . minor changes to some names and values (for consistency),
  1505   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1506   . separator between mutual domain defs: changed "," to "and",
  1507   . improved handling of sort constraints;  now they have to
  1508     appear on the left-hand side of the equations only;
  1509 
  1510 * fixed LAM <x,y,zs>.b syntax;
  1511 
  1512 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1513 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1514 
  1515 
  1516 *** FOL and ZF ***
  1517 
  1518 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1519   with `addloop' of the simplifier to faciliate case splitting in premises.
  1520 
  1521 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1522 in HOL, they strip ALL and --> from proved theorems;
  1523 
  1524 
  1525 
  1526 New in Isabelle94-8 (May 1997)
  1527 ------------------------------
  1528 
  1529 *** General Changes ***
  1530 
  1531 * new utilities to build / run / maintain Isabelle etc. (in parts
  1532 still somewhat experimental); old Makefiles etc. still functional;
  1533 
  1534 * new 'Isabelle System Manual';
  1535 
  1536 * INSTALL text, together with ./configure and ./build scripts;
  1537 
  1538 * reimplemented type inference for greater efficiency, better error
  1539 messages and clean internal interface;
  1540 
  1541 * prlim command for dealing with lots of subgoals (an easier way of
  1542 setting goals_limit);
  1543 
  1544 
  1545 *** Syntax ***
  1546 
  1547 * supports alternative (named) syntax tables (parser and pretty
  1548 printer); internal interface is provided by add_modesyntax(_i);
  1549 
  1550 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1551 be used in conjunction with the Isabelle symbol font; uses the
  1552 "symbols" syntax table;
  1553 
  1554 * added token_translation interface (may translate name tokens in
  1555 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1556 the current print_mode); IMPORTANT: user print translation functions
  1557 are responsible for marking newly introduced bounds
  1558 (Syntax.mark_boundT);
  1559 
  1560 * token translations for modes "xterm" and "xterm_color" that display
  1561 names in bold, underline etc. or colors (which requires a color
  1562 version of xterm);
  1563 
  1564 * infixes may now be declared with names independent of their syntax;
  1565 
  1566 * added typed_print_translation (like print_translation, but may
  1567 access type of constant);
  1568 
  1569 
  1570 *** Classical Reasoner ***
  1571 
  1572 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1573 some limitations.  Blast_tac...
  1574   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1575   + ignores elimination rules that don't have the correct format
  1576         (the conclusion MUST be a formula variable)
  1577   + ignores types, which can make HOL proofs fail
  1578   + rules must not require higher-order unification, e.g. apply_type in ZF
  1579     [message "Function Var's argument not a bound variable" relates to this]
  1580   + its proof strategy is more general but can actually be slower
  1581 
  1582 * substitution with equality assumptions no longer permutes other
  1583 assumptions;
  1584 
  1585 * minor changes in semantics of addafter (now called addaltern); renamed
  1586 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1587 (and access functions for it);
  1588 
  1589 * improved combination of classical reasoner and simplifier:
  1590   + functions for handling clasimpsets
  1591   + improvement of addss: now the simplifier is called _after_ the
  1592     safe steps.
  1593   + safe variant of addss called addSss: uses safe simplifications
  1594     _during_ the safe steps. It is more complete as it allows multiple
  1595     instantiations of unknowns (e.g. with slow_tac).
  1596 
  1597 *** Simplifier ***
  1598 
  1599 * added interface for simplification procedures (functions that
  1600 produce *proven* rewrite rules on the fly, depending on current
  1601 redex);
  1602 
  1603 * ordering on terms as parameter (used for ordered rewriting);
  1604 
  1605 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1606 
  1607 * the solver is now split into a safe and an unsafe part.
  1608 This should be invisible for the normal user, except that the
  1609 functions setsolver and addsolver have been renamed to setSolver and
  1610 addSolver; added safe_asm_full_simp_tac;
  1611 
  1612 
  1613 *** HOL ***
  1614 
  1615 * a generic induction tactic `induct_tac' which works for all datatypes and
  1616 also for type `nat';
  1617 
  1618 * a generic case distinction tactic `exhaust_tac' which works for all
  1619 datatypes and also for type `nat';
  1620 
  1621 * each datatype comes with a function `size';
  1622 
  1623 * patterns in case expressions allow tuple patterns as arguments to
  1624 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1625 
  1626 * primrec now also works with type nat;
  1627 
  1628 * recdef: a new declaration form, allows general recursive functions to be
  1629 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1630 
  1631 * the constant for negation has been renamed from "not" to "Not" to
  1632 harmonize with FOL, ZF, LK, etc.;
  1633 
  1634 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1635 infinite lists;
  1636 
  1637 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1638 
  1639 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1640 problems in commutative rings, using axiomatic type classes for + and *;
  1641 
  1642 * more examples in HOL/MiniML and HOL/Auth;
  1643 
  1644 * more default rewrite rules for quantifiers, union/intersection;
  1645 
  1646 * a new constant `arbitrary == @x.False';
  1647 
  1648 * HOLCF/IOA replaces old HOL/IOA;
  1649 
  1650 * HOLCF changes: derived all rules and arities
  1651   + axiomatic type classes instead of classes
  1652   + typedef instead of faking type definitions
  1653   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1654   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1655   + eliminated the types void, one, tr
  1656   + use unit lift and bool lift (with translations) instead of one and tr
  1657   + eliminated blift from Lift3.thy (use Def instead of blift)
  1658   all eliminated rules are derived as theorems --> no visible changes ;
  1659 
  1660 
  1661 *** ZF ***
  1662 
  1663 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1664 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1665 as ZF_cs addSIs [equalityI];
  1666 
  1667 
  1668 
  1669 New in Isabelle94-7 (November 96)
  1670 ---------------------------------
  1671 
  1672 * allowing negative levels (as offsets) in prlev and choplev;
  1673 
  1674 * super-linear speedup for large simplifications;
  1675 
  1676 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1677 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1678 FAIL); can suppress it using the command Delsimps (ex_simps @
  1679 all_simps); De Morgan laws are also now included, by default;
  1680 
  1681 * improved printing of ==>  :  ~:
  1682 
  1683 * new object-logic "Sequents" adds linear logic, while replacing LK
  1684 and Modal (thanks to Sara Kalvala);
  1685 
  1686 * HOL/Auth: correctness proofs for authentication protocols;
  1687 
  1688 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1689 examples on HOL/Auth);
  1690 
  1691 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1692 the rewriter and classical reasoner simultaneously;
  1693 
  1694 * function uresult no longer returns theorems in "standard" format;
  1695 regain previous version by: val uresult = standard o uresult;
  1696 
  1697 
  1698 
  1699 New in Isabelle94-6
  1700 -------------------
  1701 
  1702 * oracles -- these establish an interface between Isabelle and trusted
  1703 external reasoners, which may deliver results as theorems;
  1704 
  1705 * proof objects (in particular record all uses of oracles);
  1706 
  1707 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1708 
  1709 * "constdefs" section in theory files;
  1710 
  1711 * "primrec" section (HOL) no longer requires names;
  1712 
  1713 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1714 
  1715 
  1716 
  1717 New in Isabelle94-5
  1718 -------------------
  1719 
  1720 * reduced space requirements;
  1721 
  1722 * automatic HTML generation from theories;
  1723 
  1724 * theory files no longer require "..." (quotes) around most types;
  1725 
  1726 * new examples, including two proofs of the Church-Rosser theorem;
  1727 
  1728 * non-curried (1994) version of HOL is no longer distributed;
  1729 
  1730 
  1731 
  1732 New in Isabelle94-4
  1733 -------------------
  1734 
  1735 * greatly reduced space requirements;
  1736 
  1737 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1738 
  1739 * searchable theorem database (see the section "Retrieving theorems" on
  1740 page 8 of the Reference Manual);
  1741 
  1742 * new examples, including Grabczewski's monumental case study of the
  1743 Axiom of Choice;
  1744 
  1745 * The previous version of HOL renamed to Old_HOL;
  1746 
  1747 * The new version of HOL (previously called CHOL) uses a curried syntax
  1748 for functions.  Application looks like f a b instead of f(a,b);
  1749 
  1750 * Mutually recursive inductive definitions finally work in HOL;
  1751 
  1752 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1753 translates to the operator "split";
  1754 
  1755 
  1756 
  1757 New in Isabelle94-3
  1758 -------------------
  1759 
  1760 * new infix operator, addss, allowing the classical reasoner to
  1761 perform simplification at each step of its search.  Example:
  1762         fast_tac (cs addss ss)
  1763 
  1764 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1765 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1766 look like (a,b) instead of <a,b>;
  1767 
  1768 * PLEASE NOTE: CHOL will eventually replace HOL!
  1769 
  1770 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1771 It translates to the operator "split".  A new theory of integers is available;
  1772 
  1773 * In ZF, integer numerals now denote two's-complement binary integers.
  1774 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1775 
  1776 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1777 of the Axiom of Choice;
  1778 
  1779 
  1780 
  1781 New in Isabelle94-2
  1782 -------------------
  1783 
  1784 * Significantly faster resolution;
  1785 
  1786 * the different sections in a .thy file can now be mixed and repeated
  1787 freely;
  1788 
  1789 * Database of theorems for FOL, HOL and ZF.  New
  1790 commands including qed, qed_goal and bind_thm store theorems in the database.
  1791 
  1792 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1793 a given theory (thms_of), or find out what theory a theorem was proved in
  1794 (theory_of_thm);
  1795 
  1796 * Bugs fixed in the inductive definition and datatype packages;
  1797 
  1798 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1799 and HOL_dup_cs obsolete;
  1800 
  1801 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1802 have been removed;
  1803 
  1804 * Simpler definition of function space in ZF;
  1805 
  1806 * new results about cardinal and ordinal arithmetic in ZF;
  1807 
  1808 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1809 types;
  1810 
  1811 
  1812 $Id$