NEWS
author wenzelm
Thu Oct 04 16:07:43 2001 +0200 (2001-10-04)
changeset 11690 cb64368fb405
parent 11663 8a86409108fe
child 11700 a0e6bda62b7b
permissions -rw-r--r--
improved proof by cases and induction;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2001 (?? 2001)
     6 -----------------------------
     7 
     8 *** Document preparation ***
     9 
    10 * support bold style (for single symbols only), input syntax is like
    11 this: "\<^bold>\<alpha>" or "\<^bold>A";
    12 
    13 * \<bullet> is no output as bold \cdot by default, which looks much
    14 better in printed text;
    15 
    16 
    17 *** Isar ***
    18 
    19 * renamed "antecedent" case to "rule_context";
    20 
    21 * improved proof by cases and induction:
    22   - moved induct/cases attributes to Pure;
    23   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    24   - generic setup instantiated for FOL and HOL;
    25   - removed obsolete "(simplified)" and "(stripped)" options;
    26 
    27 * HOL: 'recdef' now fails on unfinished automated proofs, use
    28 "(permissive)" option to recover old behavior;
    29 
    30 * HOL: 'inductive' now longer features separate (collective)
    31 attributes for 'intros';
    32 
    33 
    34 *** HOL ***
    35 
    36 * HOL: linorder_less_split superseded by linorder_cases;
    37 
    38 * HOL: added "The" definite description operator; move Hilbert's "Eps"
    39 to peripheral theory "Hilbert_Choice";
    40 
    41 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
    42 in this (rare) case use:
    43 
    44   delSWrapper "split_all_tac"
    45   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
    46 
    47 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
    48 MAY FAIL;
    49 
    50 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
    51 Isabelle's type classes, ^ on functions and relations has too general
    52 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
    53 necessary to attach explicit type constraints;
    54 
    55 * HOL: syntax translations now work properly with numerals and records
    56 expressions;
    57 
    58 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
    59 Florian Kammüller;
    60 
    61 * HOL: eliminated global items
    62 
    63   const "()" -> "Product_Type.Unity"
    64   type "unit" -> "Product_Type.unit"
    65 
    66 
    67 *** ZF ***
    68 
    69 * ZF: the integer library now covers quotients and remainders, with
    70 many laws relating division to addition, multiplication, etc.;
    71 
    72 
    73 *** General ***
    74 
    75 * Meta-level proof terms (by Stefan Berghofer), see also ref manual;
    76 
    77 * Classical reasoner: renamed addaltern to addafter, addSaltern to
    78 addSafter;
    79 
    80 * syntax: support non-oriented infixes;
    81 
    82 * print modes "type_brackets" and "no_type_brackets" control output of
    83 nested => (types); the default behavior is "brackets";
    84 
    85 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
    86 
    87 * system: Proof General keywords specification is now part of the
    88 Isabelle distribution (see etc/isar-keywords.el);
    89 
    90 * system: smart selection of Isabelle process versus Isabelle
    91 interface, accommodates case-insensitive file systems (e.g. HFS+); may
    92 run both "isabelle" and "Isabelle" even if file names are badly
    93 damaged (executable inspects the case of the first letter of its own
    94 name); added separate "isabelle-process" and "isabelle-interface";
    95 
    96 
    97 
    98 New in Isabelle99-2 (February 2001)
    99 -----------------------------------
   100 
   101 *** Overview of INCOMPATIBILITIES ***
   102 
   103 * HOL: please note that theories in the Library and elsewhere often use the
   104 new-style (Isar) format; to refer to their theorems in an ML script you must
   105 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   106 
   107 * HOL: inductive package no longer splits induction rule aggressively,
   108 but only as far as specified by the introductions given; the old
   109 format may be recovered via ML function complete_split_rule or attribute
   110 'split_rule (complete)';
   111 
   112 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   113 gfp_Tarski to gfp_unfold;
   114 
   115 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   116 
   117 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   118 relation); infix "^^" has been renamed "``"; infix "``" has been
   119 renamed "`"; "univalent" has been renamed "single_valued";
   120 
   121 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   122 operation;
   123 
   124 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   125 
   126 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   127 
   128 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   129 consequence, it is no longer monotonic wrt. the local goal context
   130 (which is now passed through the inductive cases);
   131 
   132 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   133 \<gg> to \<ggreater>;
   134 
   135 
   136 *** Document preparation ***
   137 
   138 * \isabellestyle{NAME} selects version of Isabelle output (currently
   139 available: are "it" for near math-mode best-style output, "sl" for
   140 slanted text style, and "tt" for plain type-writer; if no
   141 \isabellestyle command is given, output is according to slanted
   142 type-writer);
   143 
   144 * support sub/super scripts (for single symbols only), input syntax is
   145 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   146 
   147 * some more standard symbols; see Appendix A of the system manual for
   148 the complete list of symbols defined in isabellesym.sty;
   149 
   150 * improved isabelle style files; more abstract symbol implementation
   151 (should now use \isamath{...} and \isatext{...} in custom symbol
   152 definitions);
   153 
   154 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   155 state; Note that presentation of goal states does not conform to
   156 actual human-readable proof documents.  Please do not include goal
   157 states into document output unless you really know what you are doing!
   158 
   159 * proper indentation of antiquoted output with proportional LaTeX
   160 fonts;
   161 
   162 * no_document ML operator temporarily disables LaTeX document
   163 generation;
   164 
   165 * isatool unsymbolize tunes sources for plain ASCII communication;
   166 
   167 
   168 *** Isar ***
   169 
   170 * Pure: Isar now suffers initial goal statements to contain unbound
   171 schematic variables (this does not conform to actual readable proof
   172 documents, due to unpredictable outcome and non-compositional proof
   173 checking); users who know what they are doing may use schematic goals
   174 for Prolog-style synthesis of proven results;
   175 
   176 * Pure: assumption method (an implicit finishing) now handles actual
   177 rules as well;
   178 
   179 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   180 initial goal, declare "that" only as Pure intro (only for single
   181 steps); the "that" rule assumption may now be involved in implicit
   182 finishing, thus ".." becomes a feasible for trivial obtains;
   183 
   184 * Pure: default proof step now includes 'intro_classes'; thus trivial
   185 instance proofs may be performed by "..";
   186 
   187 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   188 statements as well;
   189 
   190 * Pure: more robust selection of calculational rules;
   191 
   192 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   193 rule (as well as the assumption rule);
   194 
   195 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   196 lemmas, using the graph browser tool;
   197 
   198 * Pure: predict failure of "show" in interactive mode;
   199 
   200 * Pure: 'thms_containing' now takes actual terms as arguments;
   201 
   202 * HOL: improved method 'induct' --- now handles non-atomic goals
   203 (potential INCOMPATIBILITY); tuned error handling;
   204 
   205 * HOL: cases and induct rules now provide explicit hints about the
   206 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   207 any remaining facts are inserted into the goal verbatim;
   208 
   209 * HOL: local contexts (aka cases) may now contain term bindings as
   210 well; the 'cases' and 'induct' methods new provide a ?case binding for
   211 the result to be shown in each case;
   212 
   213 * HOL: added 'recdef_tc' command;
   214 
   215 * isatool convert assists in eliminating legacy ML scripts;
   216 
   217 
   218 *** HOL ***
   219 
   220 * HOL/Library: a collection of generic theories to be used together
   221 with main HOL; the theory loader path already includes this directory
   222 by default; the following existing theories have been moved here:
   223 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   224 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   225 
   226 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   227 modelling and verification task performed in Isabelle/HOL +
   228 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   229 
   230 * HOL/Algebra: special summation operator SUM no longer exists, it has
   231 been replaced by setsum; infix 'assoc' now has priority 50 (like
   232 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   233 'domain', this makes the theory consistent with mathematical
   234 literature;
   235 
   236 * HOL basics: added overloaded operations "inverse" and "divide"
   237 (infix "/"), syntax for generic "abs" operation, generic summation
   238 operator \<Sum>;
   239 
   240 * HOL/typedef: simplified package, provide more useful rules (see also
   241 HOL/subset.thy);
   242 
   243 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   244 now expressed as a proper nested rule (old-style tactic scripts may
   245 require atomize_strip_tac to cope with non-atomic premises);
   246 
   247 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   248 to "split_conv" (old name still available for compatibility);
   249 
   250 * HOL: improved concrete syntax for strings (e.g. allows translation
   251 rules with string literals);
   252 
   253 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   254 and Fleuriot's mechanization of analysis;
   255 
   256 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   257 
   258 
   259 *** CTT ***
   260 
   261 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   262 "lam" is displayed as TWO lambda-symbols
   263 
   264 * CTT: theory Main now available, containing everything (that is, Bool
   265 and Arith);
   266 
   267 
   268 *** General ***
   269 
   270 * Pure: the Simplifier has been implemented properly as a derived rule
   271 outside of the actual kernel (at last!); the overall performance
   272 penalty in practical applications is about 50%, while reliability of
   273 the Isabelle inference kernel has been greatly improved;
   274 
   275 * print modes "brackets" and "no_brackets" control output of nested =>
   276 (types) and ==> (props); the default behaviour is "brackets";
   277 
   278 * Provers: fast_tac (and friends) now handle actual object-logic rules
   279 as assumptions as well;
   280 
   281 * system: support Poly/ML 4.0;
   282 
   283 * system: isatool install handles KDE version 1 or 2;
   284 
   285 
   286 
   287 New in Isabelle99-1 (October 2000)
   288 ----------------------------------
   289 
   290 *** Overview of INCOMPATIBILITIES ***
   291 
   292 * HOL: simplification of natural numbers is much changed; to partly
   293 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   294 issue the following ML commands:
   295 
   296   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   297   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   298 
   299 * HOL: simplification no longer dives into case-expressions; this is
   300 controlled by "t.weak_case_cong" for each datatype t;
   301 
   302 * HOL: nat_less_induct renamed to less_induct;
   303 
   304 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   305 fixsome to patch .thy and .ML sources automatically;
   306 
   307   select_equality  -> some_equality
   308   select_eq_Ex     -> some_eq_ex
   309   selectI2EX       -> someI2_ex
   310   selectI2         -> someI2
   311   selectI          -> someI
   312   select1_equality -> some1_equality
   313   Eps_sym_eq       -> some_sym_eq_trivial
   314   Eps_eq           -> some_eq_trivial
   315 
   316 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   317 
   318 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   319 instead);
   320 
   321 * HOL: the recursion equations generated by 'recdef' are now called
   322 f.simps instead of f.rules;
   323 
   324 * HOL: qed_spec_mp now also handles bounded ALL as well;
   325 
   326 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   327 sometimes be needed;
   328 
   329 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   330 
   331 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   332 
   333 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   334 product is now "<*>" instead of "Times"; the lexicographic product is
   335 now "<*lex*>" instead of "**";
   336 
   337 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   338 of main HOL, but was unused); better use HOL's datatype package;
   339 
   340 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   341 the old syntax may be recovered as follows:
   342 
   343   syntax (symbols)
   344     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   345       (infixl "\\<oplus>" 100)
   346 
   347 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   348 
   349 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   350 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   351 internally;
   352 
   353 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   354 changed from A/r to A//r;
   355 
   356 * ZF: new treatment of arithmetic (nat & int) may break some old
   357 proofs;
   358 
   359 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   360 rulify -> rule_format, elimify -> elim_format, ...);
   361 
   362 * Isar/Provers: intro/elim/dest attributes changed; renamed
   363 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   364 should have to change intro!! to intro? only); replaced "delrule" by
   365 "rule del";
   366 
   367 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   368 
   369 * Provers: strengthened force_tac by using new first_best_tac;
   370 
   371 * LaTeX document preparation: several changes of isabelle.sty (see
   372 lib/texinputs);
   373 
   374 
   375 *** Document preparation ***
   376 
   377 * formal comments (text blocks etc.) in new-style theories may now
   378 contain antiquotations of thm/prop/term/typ/text to be presented
   379 according to latex print mode; concrete syntax is like this:
   380 @{term[show_types] "f(x) = a + x"};
   381 
   382 * isatool mkdir provides easy setup of Isabelle session directories,
   383 including proper document sources;
   384 
   385 * generated LaTeX sources are now deleted after successful run
   386 (isatool document -c); may retain a copy somewhere else via -D option
   387 of isatool usedir;
   388 
   389 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   390 style files, achieving self-contained LaTeX sources and simplifying
   391 LaTeX debugging;
   392 
   393 * old-style theories now produce (crude) LaTeX output as well;
   394 
   395 * browser info session directories are now self-contained (may be put
   396 on WWW server seperately); improved graphs of nested sessions; removed
   397 graph for 'all sessions';
   398 
   399 * several improvements in isabelle style files; \isabellestyle{it}
   400 produces fake math mode output; \isamarkupheader is now \section by
   401 default; see lib/texinputs/isabelle.sty etc.;
   402 
   403 
   404 *** Isar ***
   405 
   406 * Isar/Pure: local results and corresponding term bindings are now
   407 subject to Hindley-Milner polymorphism (similar to ML); this
   408 accommodates incremental type-inference very nicely;
   409 
   410 * Isar/Pure: new derived language element 'obtain' supports
   411 generalized existence reasoning;
   412 
   413 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   414 support accumulation of results, without applying any rules yet;
   415 useful to collect intermediate results without explicit name
   416 references, and for use with transitivity rules with more than 2
   417 premises;
   418 
   419 * Isar/Pure: scalable support for case-analysis type proofs: new
   420 'case' language element refers to local contexts symbolically, as
   421 produced by certain proof methods; internally, case names are attached
   422 to theorems as "tags";
   423 
   424 * Isar/Pure: theory command 'hide' removes declarations from
   425 class/type/const name spaces;
   426 
   427 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   428 indicate potential overloading;
   429 
   430 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   431 
   432 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   433 "{a,b,c}" instead of {a,b,c};
   434 
   435 * Isar/Pure now provides its own version of intro/elim/dest
   436 attributes; useful for building new logics, but beware of confusion
   437 with the version in Provers/classical;
   438 
   439 * Isar/Pure: the local context of (non-atomic) goals is provided via
   440 case name 'antecedent';
   441 
   442 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   443 to the current context is now done automatically);
   444 
   445 * Isar/Pure: theory command 'method_setup' provides a simple interface
   446 for definining proof methods in ML;
   447 
   448 * Isar/Provers: intro/elim/dest attributes changed; renamed
   449 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   450 most cases, one should have to change intro!! to intro? only);
   451 replaced "delrule" by "rule del";
   452 
   453 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   454 'symmetric' attribute (the latter supercedes [RS sym]);
   455 
   456 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   457 method modifier); 'simp' method: 'only:' modifier removes loopers as
   458 well (including splits);
   459 
   460 * Isar/Provers: Simplifier and Classical methods now support all kind
   461 of modifiers used in the past, including 'cong', 'iff', etc.
   462 
   463 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   464 of Simplifier and Classical reasoner);
   465 
   466 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   467 now support named cases; major packages (inductive, datatype, primrec,
   468 recdef) support case names and properly name parameters;
   469 
   470 * Isar/HOL: new transitivity rules for substitution in inequalities --
   471 monotonicity conditions are extracted to be proven at end of
   472 calculations;
   473 
   474 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   475 method anyway;
   476 
   477 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   478 split_if split_if_asm; datatype package provides theorems foo.splits =
   479 foo.split foo.split_asm for each datatype;
   480 
   481 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   482 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   483 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   484 use "(cases (simplified))" method in proper proof texts);
   485 
   486 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   487 
   488 * Isar: names of theorems etc. may be natural numbers as well;
   489 
   490 * Isar: 'pr' command: optional arguments for goals_limit and
   491 ProofContext.prems_limit; no longer prints theory contexts, but only
   492 proof states;
   493 
   494 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   495 additional print modes to be specified; e.g. "pr(latex)" will print
   496 proof state according to the Isabelle LaTeX style;
   497 
   498 * Isar: improved support for emulating tactic scripts, including proof
   499 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   500 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   501 (for HOL datatypes);
   502 
   503 * Isar: simplified (more robust) goal selection of proof methods: 1st
   504 goal, all goals, or explicit goal specifier (tactic emulation); thus
   505 'proof method scripts' have to be in depth-first order;
   506 
   507 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   508 
   509 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   510 should instead use individual commands for printing items
   511 (print_commands, print_methods etc.);
   512 
   513 * Isar: added 'nothing' --- the empty list of theorems;
   514 
   515 
   516 *** HOL ***
   517 
   518 * HOL/MicroJava: formalization of a fragment of Java, together with a
   519 corresponding virtual machine and a specification of its bytecode
   520 verifier and a lightweight bytecode verifier, including proofs of
   521 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   522 Cornelia Pusch (see also the homepage of project Bali at
   523 http://isabelle.in.tum.de/Bali/);
   524 
   525 * HOL/Algebra: new theory of rings and univariate polynomials, by
   526 Clemens Ballarin;
   527 
   528 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   529 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   530 Rasmussen;
   531 
   532 * HOL/Lattice: fundamental concepts of lattice theory and order
   533 structures, including duals, properties of bounds versus algebraic
   534 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   535 Theorem for complete lattices etc.; may also serve as a demonstration
   536 for abstract algebraic reasoning using axiomatic type classes, and
   537 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   538 
   539 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   540 von Oheimb;
   541 
   542 * HOL/IMPP: extension of IMP with local variables and mutually
   543 recursive procedures, by David von Oheimb;
   544 
   545 * HOL/Lambda: converted into new-style theory and document;
   546 
   547 * HOL/ex/Multiquote: example of multiple nested quotations and
   548 anti-quotations -- basically a generalized version of de-Bruijn
   549 representation; very useful in avoiding lifting of operations;
   550 
   551 * HOL/record: added general record equality rule to simpset; fixed
   552 select-update simplification procedure to handle extended records as
   553 well; admit "r" as field name;
   554 
   555 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   556 other numeric types and also as the identity of groups, rings, etc.;
   557 
   558 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   559 Types nat and int belong to this axclass;
   560 
   561 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   562    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   563    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   564   two terms #m*u and #n*u are replaced by #(m+n)*u
   565     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   566   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   567     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   568 
   569 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   570 powerful prover for predicate logic but knows nothing of clasets; see
   571 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   572 
   573 * HOL: new version of "case_tac" subsumes both boolean case split and
   574 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   575 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   576 
   577 * HOL: simplification no longer dives into case-expressions: only the
   578 selector expression is simplified, but not the remaining arms; to
   579 enable full simplification of case-expressions for datatype t, you may
   580 remove t.weak_case_cong from the simpset, either globally (Delcongs
   581 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   582 
   583 * HOL/recdef: the recursion equations generated by 'recdef' for
   584 function 'f' are now called f.simps instead of f.rules; if all
   585 termination conditions are proved automatically, these simplification
   586 rules are added to the simpset, as in primrec; rules may be named
   587 individually as well, resulting in a separate list of theorems for
   588 each equation;
   589 
   590 * HOL/While is a new theory that provides a while-combinator. It
   591 permits the definition of tail-recursive functions without the
   592 provision of a termination measure. The latter is necessary once the
   593 invariant proof rule for while is applied.
   594 
   595 * HOL: new (overloaded) notation for the set of elements below/above
   596 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   597 
   598 * HOL: theorems impI, allI, ballI bound as "strip";
   599 
   600 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   601 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   602 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   603 
   604 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   605 
   606 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   607 main HOL, but was unused);
   608 
   609 * HOL: fewer consts declared as global (e.g. have to refer to
   610 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   611 
   612 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   613 in case of overlap with user translations (e.g. judgements over
   614 tuples); (note that the underlying logical represenation is still
   615 bogus);
   616 
   617 
   618 *** ZF ***
   619 
   620 * ZF: simplification automatically cancels common terms in arithmetic
   621 expressions over nat and int;
   622 
   623 * ZF: new treatment of nat to minimize type-checking: all operators
   624 coerce their operands to a natural number using the function natify,
   625 making the algebraic laws unconditional;
   626 
   627 * ZF: as above, for int: operators coerce their operands to an integer
   628 using the function intify;
   629 
   630 * ZF: the integer library now contains many of the usual laws for the
   631 orderings, including $<=, and monotonicity laws for $+ and $*;
   632 
   633 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   634 simplification;
   635 
   636 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   637 to the simplifier and classical reasoner simultaneously;
   638 
   639 
   640 *** General ***
   641 
   642 * Provers: blast_tac now handles actual object-logic rules as
   643 assumptions; note that auto_tac uses blast_tac internally as well;
   644 
   645 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   646 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   647 
   648 * Provers: delrules now handles destruct rules as well (no longer need
   649 explicit make_elim);
   650 
   651 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   652   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   653 use instead the strong form,
   654   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   655 in HOL, FOL and ZF the function cla_make_elim will create such rules
   656 from destruct-rules;
   657 
   658 * Provers: Simplifier.easy_setup provides a fast path to basic
   659 Simplifier setup for new object-logics;
   660 
   661 * Pure: AST translation rules no longer require constant head on LHS;
   662 
   663 * Pure: improved name spaces: ambiguous output is qualified; support
   664 for hiding of names;
   665 
   666 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   667 XSYMBOL_HOME; no longer need to do manual configuration in most
   668 situations;
   669 
   670 * system: compression of ML heaps images may now be controlled via -c
   671 option of isabelle and isatool usedir (currently only observed by
   672 Poly/ML);
   673 
   674 * system: isatool installfonts may handle X-Symbol fonts as well (very
   675 useful for remote X11);
   676 
   677 * system: provide TAGS file for Isabelle sources;
   678 
   679 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   680 order;
   681 
   682 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   683 timing flag supersedes proof_timing and Toplevel.trace;
   684 
   685 * ML: new combinators |>> and |>>> for incremental transformations
   686 with secondary results (e.g. certain theory extensions):
   687 
   688 * ML: PureThy.add_defs gets additional argument to indicate potential
   689 overloading (usually false);
   690 
   691 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   692 results;
   693 
   694 
   695 
   696 New in Isabelle99 (October 1999)
   697 --------------------------------
   698 
   699 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   700 
   701 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   702 are no longer simplified.  (This allows the simplifier to unfold recursive
   703 functional programs.)  To restore the old behaviour, declare
   704 
   705     Delcongs [if_weak_cong];
   706 
   707 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   708 complement;
   709 
   710 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   711 
   712 * HOL/datatype: mutual_induct_tac no longer exists --
   713   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   714 
   715 * HOL/typedef: fixed type inference for representing set; type
   716 arguments now have to occur explicitly on the rhs as type constraints;
   717 
   718 * ZF: The con_defs part of an inductive definition may no longer refer
   719 to constants declared in the same theory;
   720 
   721 * HOL, ZF: the function mk_cases, generated by the inductive
   722 definition package, has lost an argument.  To simplify its result, it
   723 uses the default simpset instead of a supplied list of theorems.
   724 
   725 * HOL/List: the constructors of type list are now Nil and Cons;
   726 
   727 * Simplifier: the type of the infix ML functions
   728         setSSolver addSSolver setSolver addSolver
   729 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   730 for packaging solvers. A solver is created via
   731         mk_solver: string -> (thm list -> int -> tactic) -> solver
   732 where the string argument is only a comment.
   733 
   734 
   735 *** Proof tools ***
   736 
   737 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   738 decision procedure for linear arithmetic. Currently it is used for
   739 types `nat', `int', and `real' in HOL (see below); it can, should and
   740 will be instantiated for other types and logics as well.
   741 
   742 * The simplifier now accepts rewrite rules with flexible heads, eg
   743      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   744   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   745   matching.
   746 
   747 
   748 *** General ***
   749 
   750 * New Isabelle/Isar subsystem provides an alternative to traditional
   751 tactical theorem proving; together with the ProofGeneral/isar user
   752 interface it offers an interactive environment for developing human
   753 readable proof documents (Isar == Intelligible semi-automated
   754 reasoning); for further information see isatool doc isar-ref,
   755 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   756 
   757 * improved and simplified presentation of theories: better HTML markup
   758 (including colors), graph views in several sizes; isatool usedir now
   759 provides a proper interface for user theories (via -P option); actual
   760 document preparation based on (PDF)LaTeX is available as well (for
   761 new-style theories only); see isatool doc system for more information;
   762 
   763 * native support for Proof General, both for classic Isabelle and
   764 Isabelle/Isar;
   765 
   766 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   767 using the graph browser tool;
   768 
   769 * Isabelle manuals now also available as PDF;
   770 
   771 * theory loader rewritten from scratch (may not be fully
   772 bug-compatible); old loadpath variable has been replaced by show_path,
   773 add_path, del_path, reset_path functions; new operations such as
   774 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   775 isatool doc ref);
   776 
   777 * improved isatool install: option -k creates KDE application icon,
   778 option -p DIR installs standalone binaries;
   779 
   780 * added ML_PLATFORM setting (useful for cross-platform installations);
   781 more robust handling of platform specific ML images for SML/NJ;
   782 
   783 * the settings environment is now statically scoped, i.e. it is never
   784 created again in sub-processes invoked from isabelle, isatool, or
   785 Isabelle;
   786 
   787 * path element specification '~~' refers to '$ISABELLE_HOME';
   788 
   789 * in locales, the "assumes" and "defines" parts may be omitted if
   790 empty;
   791 
   792 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   793 long arrows);
   794 
   795 * new print_mode "HTML";
   796 
   797 * new flag show_tags controls display of tags of theorems (which are
   798 basically just comments that may be attached by some tools);
   799 
   800 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   801 mode and goal output format:
   802 
   803 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   804 244c244
   805 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   806 ---
   807 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   808 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   809 181c181
   810 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   811 ---
   812 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   813 
   814 * function bind_thms stores lists of theorems (cf. bind_thm);
   815 
   816 * new shorthand tactics ftac, eatac, datac, fatac;
   817 
   818 * qed (and friends) now accept "" as result name; in that case the
   819 theorem is not stored, but proper checks and presentation of the
   820 result still apply;
   821 
   822 * theorem database now also indexes constants "Trueprop", "all",
   823 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   824 
   825 
   826 *** HOL ***
   827 
   828 ** HOL arithmetic **
   829 
   830 * There are now decision procedures for linear arithmetic over nat and
   831 int:
   832 
   833 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   834 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   835 are treated as atomic; subformulae not involving type `nat' or `int'
   836 are ignored; quantified subformulae are ignored unless they are
   837 positive universal or negative existential. The tactic has to be
   838 invoked by hand and can be a little bit slow. In particular, the
   839 running time is exponential in the number of occurrences of `min' and
   840 `max', and `-' on `nat'.
   841 
   842 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   843 (negated) (in)equalities among the premises and the conclusion into
   844 account (i.e. no compound formulae) and does not know about `min' and
   845 `max', and `-' on `nat'. It is fast and is used automatically by the
   846 simplifier.
   847 
   848 NB: At the moment, these decision procedures do not cope with mixed
   849 nat/int formulae where the two parts interact, such as `m < n ==>
   850 int(m) < int(n)'.
   851 
   852 * HOL/Numeral provides a generic theory of numerals (encoded
   853 efficiently as bit strings); setup for types nat/int/real is in place;
   854 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   855 int, existing theories and proof scripts may require a few additional
   856 type constraints;
   857 
   858 * integer division and remainder can now be performed on constant
   859 arguments;
   860 
   861 * many properties of integer multiplication, division and remainder
   862 are now available;
   863 
   864 * An interface to the Stanford Validity Checker (SVC) is available through the
   865 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   866 are proved automatically.  SVC must be installed separately, and its results
   867 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   868 invocation of the underlying oracle).  For SVC see
   869   http://verify.stanford.edu/SVC
   870 
   871 * IsaMakefile: the HOL-Real target now builds an actual image;
   872 
   873 
   874 ** HOL misc **
   875 
   876 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   877 (in Isabelle/Isar) -- by Gertrud Bauer;
   878 
   879 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   880 analysis for assembly languages with subtypes;
   881 
   882 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   883 -- avoids syntactic ambiguities and treats state, transition, and
   884 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   885 changed syntax and (many) tactics;
   886 
   887 * HOL/inductive: Now also handles more general introduction rules such
   888   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   889   theorems are now maintained within the theory (maintained via the
   890   "mono" attribute);
   891 
   892 * HOL/datatype: Now also handles arbitrarily branching datatypes
   893   (using function types) such as
   894 
   895   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   896 
   897 * HOL/record: record_simproc (part of the default simpset) takes care
   898 of selectors applied to updated records; record_split_tac is no longer
   899 part of the default claset; update_defs may now be removed from the
   900 simpset in many cases; COMPATIBILITY: old behavior achieved by
   901 
   902   claset_ref () := claset() addSWrapper record_split_wrapper;
   903   Delsimprocs [record_simproc]
   904 
   905 * HOL/typedef: fixed type inference for representing set; type
   906 arguments now have to occur explicitly on the rhs as type constraints;
   907 
   908 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   909 names rather than an ML expression;
   910 
   911 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   912 supplied later.  Program schemes can be defined, such as
   913     "While B C s = (if B s then While B C (C s) else s)"
   914 where the well-founded relation can be chosen after B and C have been given.
   915 
   916 * HOL/List: the constructors of type list are now Nil and Cons;
   917 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   918 course, ML tools referring to List.list.op # etc. have to be adapted;
   919 
   920 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   921 disabled by default; run isabelle with option -m HOL to get back to
   922 the original Gordon/HOL-style output;
   923 
   924 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   925 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   926 
   927 * HOL basic syntax simplified (more orthogonal): all variants of
   928 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   929 Eps operator is provided as well: "SOME x. P[x]";
   930 
   931 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   932 
   933 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   934 thus available for user theories;
   935 
   936 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   937 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   938 time;
   939 
   940 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   941 several times and then mp;
   942 
   943 
   944 *** LK ***
   945 
   946 * the notation <<...>> is now available as a notation for sequences of
   947 formulas;
   948 
   949 * the simplifier is now installed
   950 
   951 * the axiom system has been generalized (thanks to Soren Heilmann)
   952 
   953 * the classical reasoner now has a default rule database
   954 
   955 
   956 *** ZF ***
   957 
   958 * new primrec section allows primitive recursive functions to be given
   959 directly (as in HOL) over datatypes and the natural numbers;
   960 
   961 * new tactics induct_tac and exhaust_tac for induction (or case
   962 analysis) over datatypes and the natural numbers;
   963 
   964 * the datatype declaration of type T now defines the recursor T_rec;
   965 
   966 * simplification automatically does freeness reasoning for datatype
   967 constructors;
   968 
   969 * automatic type-inference, with AddTCs command to insert new
   970 type-checking rules;
   971 
   972 * datatype introduction rules are now added as Safe Introduction rules
   973 to the claset;
   974 
   975 * the syntax "if P then x else y" is now available in addition to
   976 if(P,x,y);
   977 
   978 
   979 *** Internal programming interfaces ***
   980 
   981 * tuned simplifier trace output; new flag debug_simp;
   982 
   983 * structures Vartab / Termtab (instances of TableFun) offer efficient
   984 tables indexed by indexname_ord / term_ord (compatible with aconv);
   985 
   986 * AxClass.axclass_tac lost the theory argument;
   987 
   988 * tuned current_goals_markers semantics: begin / end goal avoids
   989 printing empty lines;
   990 
   991 * removed prs and prs_fn hook, which was broken because it did not
   992 include \n in its semantics, forcing writeln to add one
   993 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   994 string -> unit if you really want to output text without newline;
   995 
   996 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   997 plain output, interface builders may have to enable 'isabelle_font'
   998 mode to get Isabelle font glyphs as before;
   999 
  1000 * refined token_translation interface; INCOMPATIBILITY: output length
  1001 now of type real instead of int;
  1002 
  1003 * theory loader actions may be traced via new ThyInfo.add_hook
  1004 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1005 your own database of information attached to *whole* theories -- as
  1006 opposed to intra-theory data slots offered via TheoryDataFun;
  1007 
  1008 * proper handling of dangling sort hypotheses (at last!);
  1009 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1010 extra sort hypotheses that can be witnessed from the type signature;
  1011 the force_strip_shyps flag is gone, any remaining shyps are simply
  1012 left in the theorem (with a warning issued by strip_shyps_warning);
  1013 
  1014 
  1015 
  1016 New in Isabelle98-1 (October 1998)
  1017 ----------------------------------
  1018 
  1019 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1020 
  1021 * several changes of automated proof tools;
  1022 
  1023 * HOL: major changes to the inductive and datatype packages, including
  1024 some minor incompatibilities of theory syntax;
  1025 
  1026 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1027 called `inj_on';
  1028 
  1029 * HOL: removed duplicate thms in Arith:
  1030   less_imp_add_less  should be replaced by  trans_less_add1
  1031   le_imp_add_le      should be replaced by  trans_le_add1
  1032 
  1033 * HOL: unary minus is now overloaded (new type constraints may be
  1034 required);
  1035 
  1036 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1037 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1038 now taken as an integer constant.
  1039 
  1040 * Pure: ML function 'theory_of' renamed to 'theory';
  1041 
  1042 
  1043 *** Proof tools ***
  1044 
  1045 * Simplifier:
  1046   1. Asm_full_simp_tac is now more aggressive.
  1047      1. It will sometimes reorient premises if that increases their power to
  1048         simplify.
  1049      2. It does no longer proceed strictly from left to right but may also
  1050         rotate premises to achieve further simplification.
  1051      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1052      old Asm_full_simp_tac in that it does not rotate premises.
  1053   2. The simplifier now knows a little bit about nat-arithmetic.
  1054 
  1055 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1056 allows for selected deletion of wrappers, by introduction of names for
  1057 wrapper functionals.  This implies that addbefore, addSbefore,
  1058 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1059 and that adding two tactics with the same name overwrites the first
  1060 one (emitting a warning).
  1061   type wrapper = (int -> tactic) -> (int -> tactic)
  1062   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1063   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1064   delWrapper, delSWrapper: claset *  string            -> claset
  1065   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1066 
  1067 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1068 semantics; addbefore now affects only the unsafe part of step_tac
  1069 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1070 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1071 by Force_tac;
  1072 
  1073 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1074 compWrapper; added safe wrapper (and access functions for it);
  1075 
  1076 * HOL/split_all_tac is now much faster and fails if there is nothing
  1077 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1078 and the names of the automatically generated variables have changed.
  1079 split_all_tac has moved within claset() from unsafe wrappers to safe
  1080 wrappers, which means that !!-bound variables are split much more
  1081 aggressively, and safe_tac and clarify_tac now split such variables.
  1082 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1083 Note: the same holds for record_split_tac, which does the job of
  1084 split_all_tac for record fields.
  1085 
  1086 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1087 permanently to the default simpset using Addsplits just like
  1088 Addsimps. They can be removed via Delsplits just like
  1089 Delsimps. Lower-case versions are also available.
  1090 
  1091 * HOL/Simplifier: The rule split_if is now part of the default
  1092 simpset. This means that the simplifier will eliminate all occurrences
  1093 of if-then-else in the conclusion of a goal. To prevent this, you can
  1094 either remove split_if completely from the default simpset by
  1095 `Delsplits [split_if]' or remove it in a specific call of the
  1096 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1097 other case splitting rules to/from the default simpset: every datatype
  1098 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1099 t is the name of the datatype).
  1100 
  1101 * Classical reasoner / Simplifier combination: new force_tac (and
  1102 derivatives Force_tac, force) combines rewriting and classical
  1103 reasoning (and whatever other tools) similarly to auto_tac, but is
  1104 aimed to solve the given subgoal completely.
  1105 
  1106 
  1107 *** General ***
  1108 
  1109 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1110 and `goalw': the theory is no longer needed as an explicit argument -
  1111 the current theory context is used; assumptions are no longer returned
  1112 at the ML-level unless one of them starts with ==> or !!; it is
  1113 recommended to convert to these new commands using isatool fixgoal
  1114 (backup your sources first!);
  1115 
  1116 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1117 the current theory context, and 'theory' to lookup stored theories;
  1118 
  1119 * new theory section 'locale' for declaring constants, assumptions and
  1120 definitions that have local scope;
  1121 
  1122 * new theory section 'nonterminals' for purely syntactic types;
  1123 
  1124 * new theory section 'setup' for generic ML setup functions
  1125 (e.g. package initialization);
  1126 
  1127 * the distribution now includes Isabelle icons: see
  1128 lib/logo/isabelle-{small,tiny}.xpm;
  1129 
  1130 * isatool install - install binaries with absolute references to
  1131 ISABELLE_HOME/bin;
  1132 
  1133 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1134 
  1135 * print mode 'emacs' reserved for Isamode;
  1136 
  1137 * support multiple print (ast) translations per constant name;
  1138 
  1139 * theorems involving oracles are now printed with a suffixed [!];
  1140 
  1141 
  1142 *** HOL ***
  1143 
  1144 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1145 
  1146 * HOL/inductive package reorganized and improved: now supports mutual
  1147 definitions such as
  1148 
  1149   inductive EVEN ODD
  1150     intrs
  1151       null "0 : EVEN"
  1152       oddI "n : EVEN ==> Suc n : ODD"
  1153       evenI "n : ODD ==> Suc n : EVEN"
  1154 
  1155 new theorem list "elims" contains an elimination rule for each of the
  1156 recursive sets; inductive definitions now handle disjunctive premises
  1157 correctly (also ZF);
  1158 
  1159 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1160 "mutual_induct" no longer exists - the induction rule is always
  1161 contained in "induct";
  1162 
  1163 
  1164 * HOL/datatype package re-implemented and greatly improved: now
  1165 supports mutually recursive datatypes such as
  1166 
  1167   datatype
  1168     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1169             | SUM ('a aexp) ('a aexp)
  1170             | DIFF ('a aexp) ('a aexp)
  1171             | NUM 'a
  1172   and
  1173     'a bexp = LESS ('a aexp) ('a aexp)
  1174             | AND ('a bexp) ('a bexp)
  1175             | OR ('a bexp) ('a bexp)
  1176 
  1177 as well as indirectly recursive datatypes such as
  1178 
  1179   datatype
  1180     ('a, 'b) term = Var 'a
  1181                   | App 'b ((('a, 'b) term) list)
  1182 
  1183 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1184 induction on mutually / indirectly recursive datatypes.
  1185 
  1186 Primrec equations are now stored in theory and can be accessed via
  1187 <function_name>.simps.
  1188 
  1189 INCOMPATIBILITIES:
  1190 
  1191   - Theories using datatypes must now have theory Datatype as an
  1192     ancestor.
  1193   - The specific <typename>.induct_tac no longer exists - use the
  1194     generic induct_tac instead.
  1195   - natE has been renamed to nat.exhaust - use exhaust_tac
  1196     instead of res_inst_tac ... natE. Note that the variable
  1197     names in nat.exhaust differ from the names in natE, this
  1198     may cause some "fragile" proofs to fail.
  1199   - The theorems split_<typename>_case and split_<typename>_case_asm
  1200     have been renamed to <typename>.split and <typename>.split_asm.
  1201   - Since default sorts of type variables are now handled correctly,
  1202     some datatype definitions may have to be annotated with explicit
  1203     sort constraints.
  1204   - Primrec definitions no longer require function name and type
  1205     of recursive argument.
  1206 
  1207 Consider using isatool fixdatatype to adapt your theories and proof
  1208 scripts to the new package (backup your sources first!).
  1209 
  1210 
  1211 * HOL/record package: considerably improved implementation; now
  1212 includes concrete syntax for record types, terms, updates; theorems
  1213 for surjective pairing and splitting !!-bound record variables; proof
  1214 support is as follows:
  1215 
  1216   1) standard conversions (selectors or updates applied to record
  1217 constructor terms) are part of the standard simpset;
  1218 
  1219   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1220 made part of standard simpset and claset via addIffs;
  1221 
  1222   3) a tactic for record field splitting (record_split_tac) is part of
  1223 the standard claset (addSWrapper);
  1224 
  1225 To get a better idea about these rules you may retrieve them via
  1226 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1227 the name of your record type.
  1228 
  1229 The split tactic 3) conceptually simplifies by the following rule:
  1230 
  1231   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1232 
  1233 Thus any record variable that is bound by meta-all will automatically
  1234 blow up into some record constructor term, consequently the
  1235 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1236 solve record problems automatically.
  1237 
  1238 
  1239 * reorganized the main HOL image: HOL/Integ and String loaded by
  1240 default; theory Main includes everything;
  1241 
  1242 * automatic simplification of integer sums and comparisons, using cancellation;
  1243 
  1244 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1245 
  1246 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1247 
  1248 * many new identities for unions, intersections, set difference, etc.;
  1249 
  1250 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1251 called split_if, split_split, split_sum_case and split_nat_case (to go
  1252 with add/delsplits);
  1253 
  1254 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1255 (?x::unit) = (); this is made part of the default simpset, which COULD
  1256 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1257 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1258 unit_abs_eta_conv is added in order to counter the effect of
  1259 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1260 %u.f();
  1261 
  1262 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1263 makes more sense);
  1264 
  1265 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1266   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1267   disjointness reasoning but breaking a few old proofs.
  1268 
  1269 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1270 to 'converse' from 'inverse' (for compatibility with ZF and some
  1271 literature);
  1272 
  1273 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1274 the well-founded relation;
  1275 
  1276 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1277     Compl A.  The "Compl" syntax remains available as input syntax for this
  1278     release ONLY.
  1279 
  1280 * HOL/Update: new theory of function updates:
  1281     f(a:=b) == %x. if x=a then b else f x
  1282 may also be iterated as in f(a:=b,c:=d,...);
  1283 
  1284 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1285 
  1286 * HOL/List:
  1287   - new function list_update written xs[i:=v] that updates the i-th
  1288     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1289   - new function `upt' written [i..j(] which generates the list
  1290     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1291     bound write [i..j], which is a shorthand for [i..j+1(].
  1292   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1293 
  1294 * HOL/Arith:
  1295   - removed 'pred' (predecessor) function;
  1296   - generalized some theorems about n-1;
  1297   - many new laws about "div" and "mod";
  1298   - new laws about greatest common divisors (see theory ex/Primes);
  1299 
  1300 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1301 instead of "inverse";
  1302 
  1303 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1304   of the multiset ordering;
  1305 
  1306 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1307   (not included by default);
  1308 
  1309 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1310 
  1311 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1312   programs, i.e. different program variables may have different types.
  1313 
  1314 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1315   [previously, this check worked only if the rewrite rule was unconditional]
  1316   Now rew can involve either definitions or equalities (either == or =).
  1317 
  1318 
  1319 *** ZF ***
  1320 
  1321 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1322   only the theorems proved on ZF.ML;
  1323 
  1324 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1325   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1326   disjointness reasoning but breaking a few old proofs.
  1327 
  1328 * ZF/Update: new theory of function updates
  1329     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1330   may also be iterated as in f(a:=b,c:=d,...);
  1331 
  1332 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1333 
  1334 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1335   [previously, this check worked only if the rewrite rule was unconditional]
  1336   Now rew can involve either definitions or equalities (either == or =).
  1337 
  1338 * case_tac provided for compatibility with HOL
  1339     (like the old excluded_middle_tac, but with subgoals swapped)
  1340 
  1341 
  1342 *** Internal programming interfaces ***
  1343 
  1344 * Pure: several new basic modules made available for general use, see
  1345 also src/Pure/README;
  1346 
  1347 * improved the theory data mechanism to support encapsulation (data
  1348 kind name replaced by private Object.kind, acting as authorization
  1349 key); new type-safe user interface via functor TheoryDataFun; generic
  1350 print_data function becomes basically useless;
  1351 
  1352 * removed global_names compatibility flag -- all theory declarations
  1353 are qualified by default;
  1354 
  1355 * module Pure/Syntax now offers quote / antiquote translation
  1356 functions (useful for Hoare logic etc. with implicit dependencies);
  1357 see HOL/ex/Antiquote for an example use;
  1358 
  1359 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1360 cterm -> thm;
  1361 
  1362 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1363 subgoal;
  1364 
  1365 * Display.print_goals function moved to Locale.print_goals;
  1366 
  1367 * standard print function for goals supports current_goals_markers
  1368 variable for marking begin of proof, end of proof, start of goal; the
  1369 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1370 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1371 for example;
  1372 
  1373 
  1374 
  1375 New in Isabelle98 (January 1998)
  1376 --------------------------------
  1377 
  1378 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1379 
  1380 * changed lexical syntax of terms / types: dots made part of long
  1381 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1382 
  1383 * simpset (and claset) reference variable replaced by functions
  1384 simpset / simpset_ref;
  1385 
  1386 * no longer supports theory aliases (via merge) and non-trivial
  1387 implicit merge of thms' signatures;
  1388 
  1389 * most internal names of constants changed due to qualified names;
  1390 
  1391 * changed Pure/Sequence interface (see Pure/seq.ML);
  1392 
  1393 
  1394 *** General Changes ***
  1395 
  1396 * hierachically structured name spaces (for consts, types, axms, thms
  1397 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1398 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1399 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1400 long_names for fully qualified output names; NOTE: ML programs
  1401 (special tactics, packages etc.) referring to internal names may have
  1402 to be adapted to cope with fully qualified names; in case of severe
  1403 backward campatibility problems try setting 'global_names' at compile
  1404 time to have enrything declared within a flat name space; one may also
  1405 fine tune name declarations in theories via the 'global' and 'local'
  1406 section;
  1407 
  1408 * reimplemented the implicit simpset and claset using the new anytype
  1409 data filed in signatures; references simpset:simpset ref etc. are
  1410 replaced by functions simpset:unit->simpset and
  1411 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1412 to patch your ML files accordingly;
  1413 
  1414 * HTML output now includes theory graph data for display with Java
  1415 applet or isatool browser; data generated automatically via isatool
  1416 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1417 
  1418 * defs may now be conditional; improved rewrite_goals_tac to handle
  1419 conditional equations;
  1420 
  1421 * defs now admits additional type arguments, using TYPE('a) syntax;
  1422 
  1423 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1424 creates a new theory node; implicit merge of thms' signatures is
  1425 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1426 transfer:theory->thm->thm in (rare) cases;
  1427 
  1428 * improved handling of draft signatures / theories; draft thms (and
  1429 ctyps, cterms) are automatically promoted to real ones;
  1430 
  1431 * slightly changed interfaces for oracles: admit many per theory, named
  1432 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1433 
  1434 * print_goals: optional output of const types (set show_consts and
  1435 show_types);
  1436 
  1437 * improved output of warnings (###) and errors (***);
  1438 
  1439 * subgoal_tac displays a warning if the new subgoal has type variables;
  1440 
  1441 * removed old README and Makefiles;
  1442 
  1443 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1444 
  1445 * removed obsolete init_pps and init_database;
  1446 
  1447 * deleted the obsolete tactical STATE, which was declared by
  1448     fun STATE tacfun st = tacfun st st;
  1449 
  1450 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1451 (which abbreviates $HOME);
  1452 
  1453 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1454 use isatool fixseq to adapt your ML programs (this works for fully
  1455 qualified references to the Sequence structure only!);
  1456 
  1457 * use_thy no longer requires writable current directory; it always
  1458 reloads .ML *and* .thy file, if either one is out of date;
  1459 
  1460 
  1461 *** Classical Reasoner ***
  1462 
  1463 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1464 tactics that use classical reasoning to simplify a subgoal without
  1465 splitting it into several subgoals;
  1466 
  1467 * Safe_tac: like safe_tac but uses the default claset;
  1468 
  1469 
  1470 *** Simplifier ***
  1471 
  1472 * added simplification meta rules:
  1473     (asm_)(full_)simplify: simpset -> thm -> thm;
  1474 
  1475 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1476 logics (again);
  1477 
  1478 * added prems argument to simplification procedures;
  1479 
  1480 * HOL, FOL, ZF: added infix function `addsplits':
  1481   instead of `<simpset> setloop (split_tac <thms>)'
  1482   you can simply write `<simpset> addsplits <thms>'
  1483 
  1484 
  1485 *** Syntax ***
  1486 
  1487 * TYPE('a) syntax for type reflection terms;
  1488 
  1489 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1490 
  1491 * pretty printer: changed order of mixfix annotation preference (again!);
  1492 
  1493 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1494 
  1495 
  1496 *** HOL ***
  1497 
  1498 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1499   with `addloop' of the simplifier to faciliate case splitting in premises.
  1500 
  1501 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1502 
  1503 * HOL/Auth: new protocol proofs including some for the Internet
  1504   protocol TLS;
  1505 
  1506 * HOL/Map: new theory of `maps' a la VDM;
  1507 
  1508 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1509 cancelling out common nat summands from =, <, <= (in)equalities, or
  1510 differences; simplification procedures nat_cancel_factor for
  1511 cancelling common factor from =, <, <= (in)equalities over natural
  1512 sums; nat_cancel contains both kinds of procedures, it is installed by
  1513 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1514 
  1515 * HOL/simplifier: terms of the form
  1516   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1517   are rewritten to
  1518   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1519   and those of the form
  1520   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1521   are rewritten to
  1522   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1523 
  1524 * HOL/datatype
  1525   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1526 
  1527   P(t_case f1 ... fn x) =
  1528      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1529         ...
  1530        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1531      )
  1532 
  1533   and a theorem `split_t_case_asm' of the form
  1534 
  1535   P(t_case f1 ... fn x) =
  1536     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1537         ...
  1538        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1539      )
  1540   which can be added to a simpset via `addsplits'. The existing theorems
  1541   expand_list_case and expand_option_case have been renamed to
  1542   split_list_case and split_option_case.
  1543 
  1544 * HOL/Arithmetic:
  1545   - `pred n' is automatically converted to `n-1'.
  1546     Users are strongly encouraged not to use `pred' any longer,
  1547     because it will disappear altogether at some point.
  1548   - Users are strongly encouraged to write "0 < n" rather than
  1549     "n ~= 0". Theorems and proof tools have been modified towards this
  1550     `standard'.
  1551 
  1552 * HOL/Lists:
  1553   the function "set_of_list" has been renamed "set" (and its theorems too);
  1554   the function "nth" now takes its arguments in the reverse order and
  1555   has acquired the infix notation "!" as in "xs!n".
  1556 
  1557 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1558 
  1559 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1560   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1561 
  1562 * HOL/record: extensible records with schematic structural subtyping
  1563 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1564 still lacks various theorems and concrete record syntax;
  1565 
  1566 
  1567 *** HOLCF ***
  1568 
  1569 * removed "axioms" and "generated by" sections;
  1570 
  1571 * replaced "ops" section by extended "consts" section, which is capable of
  1572   handling the continuous function space "->" directly;
  1573 
  1574 * domain package:
  1575   . proves theorems immediately and stores them in the theory,
  1576   . creates hierachical name space,
  1577   . now uses normal mixfix annotations (instead of cinfix...),
  1578   . minor changes to some names and values (for consistency),
  1579   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1580   . separator between mutual domain defs: changed "," to "and",
  1581   . improved handling of sort constraints;  now they have to
  1582     appear on the left-hand side of the equations only;
  1583 
  1584 * fixed LAM <x,y,zs>.b syntax;
  1585 
  1586 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1587 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1588 
  1589 
  1590 *** FOL and ZF ***
  1591 
  1592 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1593   with `addloop' of the simplifier to faciliate case splitting in premises.
  1594 
  1595 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1596 in HOL, they strip ALL and --> from proved theorems;
  1597 
  1598 
  1599 
  1600 New in Isabelle94-8 (May 1997)
  1601 ------------------------------
  1602 
  1603 *** General Changes ***
  1604 
  1605 * new utilities to build / run / maintain Isabelle etc. (in parts
  1606 still somewhat experimental); old Makefiles etc. still functional;
  1607 
  1608 * new 'Isabelle System Manual';
  1609 
  1610 * INSTALL text, together with ./configure and ./build scripts;
  1611 
  1612 * reimplemented type inference for greater efficiency, better error
  1613 messages and clean internal interface;
  1614 
  1615 * prlim command for dealing with lots of subgoals (an easier way of
  1616 setting goals_limit);
  1617 
  1618 
  1619 *** Syntax ***
  1620 
  1621 * supports alternative (named) syntax tables (parser and pretty
  1622 printer); internal interface is provided by add_modesyntax(_i);
  1623 
  1624 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1625 be used in conjunction with the Isabelle symbol font; uses the
  1626 "symbols" syntax table;
  1627 
  1628 * added token_translation interface (may translate name tokens in
  1629 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1630 the current print_mode); IMPORTANT: user print translation functions
  1631 are responsible for marking newly introduced bounds
  1632 (Syntax.mark_boundT);
  1633 
  1634 * token translations for modes "xterm" and "xterm_color" that display
  1635 names in bold, underline etc. or colors (which requires a color
  1636 version of xterm);
  1637 
  1638 * infixes may now be declared with names independent of their syntax;
  1639 
  1640 * added typed_print_translation (like print_translation, but may
  1641 access type of constant);
  1642 
  1643 
  1644 *** Classical Reasoner ***
  1645 
  1646 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1647 some limitations.  Blast_tac...
  1648   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1649   + ignores elimination rules that don't have the correct format
  1650         (the conclusion MUST be a formula variable)
  1651   + ignores types, which can make HOL proofs fail
  1652   + rules must not require higher-order unification, e.g. apply_type in ZF
  1653     [message "Function Var's argument not a bound variable" relates to this]
  1654   + its proof strategy is more general but can actually be slower
  1655 
  1656 * substitution with equality assumptions no longer permutes other
  1657 assumptions;
  1658 
  1659 * minor changes in semantics of addafter (now called addaltern); renamed
  1660 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1661 (and access functions for it);
  1662 
  1663 * improved combination of classical reasoner and simplifier:
  1664   + functions for handling clasimpsets
  1665   + improvement of addss: now the simplifier is called _after_ the
  1666     safe steps.
  1667   + safe variant of addss called addSss: uses safe simplifications
  1668     _during_ the safe steps. It is more complete as it allows multiple
  1669     instantiations of unknowns (e.g. with slow_tac).
  1670 
  1671 *** Simplifier ***
  1672 
  1673 * added interface for simplification procedures (functions that
  1674 produce *proven* rewrite rules on the fly, depending on current
  1675 redex);
  1676 
  1677 * ordering on terms as parameter (used for ordered rewriting);
  1678 
  1679 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1680 
  1681 * the solver is now split into a safe and an unsafe part.
  1682 This should be invisible for the normal user, except that the
  1683 functions setsolver and addsolver have been renamed to setSolver and
  1684 addSolver; added safe_asm_full_simp_tac;
  1685 
  1686 
  1687 *** HOL ***
  1688 
  1689 * a generic induction tactic `induct_tac' which works for all datatypes and
  1690 also for type `nat';
  1691 
  1692 * a generic case distinction tactic `exhaust_tac' which works for all
  1693 datatypes and also for type `nat';
  1694 
  1695 * each datatype comes with a function `size';
  1696 
  1697 * patterns in case expressions allow tuple patterns as arguments to
  1698 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1699 
  1700 * primrec now also works with type nat;
  1701 
  1702 * recdef: a new declaration form, allows general recursive functions to be
  1703 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1704 
  1705 * the constant for negation has been renamed from "not" to "Not" to
  1706 harmonize with FOL, ZF, LK, etc.;
  1707 
  1708 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1709 infinite lists;
  1710 
  1711 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1712 
  1713 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1714 problems in commutative rings, using axiomatic type classes for + and *;
  1715 
  1716 * more examples in HOL/MiniML and HOL/Auth;
  1717 
  1718 * more default rewrite rules for quantifiers, union/intersection;
  1719 
  1720 * a new constant `arbitrary == @x.False';
  1721 
  1722 * HOLCF/IOA replaces old HOL/IOA;
  1723 
  1724 * HOLCF changes: derived all rules and arities
  1725   + axiomatic type classes instead of classes
  1726   + typedef instead of faking type definitions
  1727   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1728   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1729   + eliminated the types void, one, tr
  1730   + use unit lift and bool lift (with translations) instead of one and tr
  1731   + eliminated blift from Lift3.thy (use Def instead of blift)
  1732   all eliminated rules are derived as theorems --> no visible changes ;
  1733 
  1734 
  1735 *** ZF ***
  1736 
  1737 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1738 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1739 as ZF_cs addSIs [equalityI];
  1740 
  1741 
  1742 
  1743 New in Isabelle94-7 (November 96)
  1744 ---------------------------------
  1745 
  1746 * allowing negative levels (as offsets) in prlev and choplev;
  1747 
  1748 * super-linear speedup for large simplifications;
  1749 
  1750 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1751 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1752 FAIL); can suppress it using the command Delsimps (ex_simps @
  1753 all_simps); De Morgan laws are also now included, by default;
  1754 
  1755 * improved printing of ==>  :  ~:
  1756 
  1757 * new object-logic "Sequents" adds linear logic, while replacing LK
  1758 and Modal (thanks to Sara Kalvala);
  1759 
  1760 * HOL/Auth: correctness proofs for authentication protocols;
  1761 
  1762 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1763 examples on HOL/Auth);
  1764 
  1765 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1766 the rewriter and classical reasoner simultaneously;
  1767 
  1768 * function uresult no longer returns theorems in "standard" format;
  1769 regain previous version by: val uresult = standard o uresult;
  1770 
  1771 
  1772 
  1773 New in Isabelle94-6
  1774 -------------------
  1775 
  1776 * oracles -- these establish an interface between Isabelle and trusted
  1777 external reasoners, which may deliver results as theorems;
  1778 
  1779 * proof objects (in particular record all uses of oracles);
  1780 
  1781 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1782 
  1783 * "constdefs" section in theory files;
  1784 
  1785 * "primrec" section (HOL) no longer requires names;
  1786 
  1787 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1788 
  1789 
  1790 
  1791 New in Isabelle94-5
  1792 -------------------
  1793 
  1794 * reduced space requirements;
  1795 
  1796 * automatic HTML generation from theories;
  1797 
  1798 * theory files no longer require "..." (quotes) around most types;
  1799 
  1800 * new examples, including two proofs of the Church-Rosser theorem;
  1801 
  1802 * non-curried (1994) version of HOL is no longer distributed;
  1803 
  1804 
  1805 
  1806 New in Isabelle94-4
  1807 -------------------
  1808 
  1809 * greatly reduced space requirements;
  1810 
  1811 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1812 
  1813 * searchable theorem database (see the section "Retrieving theorems" on
  1814 page 8 of the Reference Manual);
  1815 
  1816 * new examples, including Grabczewski's monumental case study of the
  1817 Axiom of Choice;
  1818 
  1819 * The previous version of HOL renamed to Old_HOL;
  1820 
  1821 * The new version of HOL (previously called CHOL) uses a curried syntax
  1822 for functions.  Application looks like f a b instead of f(a,b);
  1823 
  1824 * Mutually recursive inductive definitions finally work in HOL;
  1825 
  1826 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1827 translates to the operator "split";
  1828 
  1829 
  1830 
  1831 New in Isabelle94-3
  1832 -------------------
  1833 
  1834 * new infix operator, addss, allowing the classical reasoner to
  1835 perform simplification at each step of its search.  Example:
  1836         fast_tac (cs addss ss)
  1837 
  1838 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1839 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1840 look like (a,b) instead of <a,b>;
  1841 
  1842 * PLEASE NOTE: CHOL will eventually replace HOL!
  1843 
  1844 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1845 It translates to the operator "split".  A new theory of integers is available;
  1846 
  1847 * In ZF, integer numerals now denote two's-complement binary integers.
  1848 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1849 
  1850 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1851 of the Axiom of Choice;
  1852 
  1853 
  1854 
  1855 New in Isabelle94-2
  1856 -------------------
  1857 
  1858 * Significantly faster resolution;
  1859 
  1860 * the different sections in a .thy file can now be mixed and repeated
  1861 freely;
  1862 
  1863 * Database of theorems for FOL, HOL and ZF.  New
  1864 commands including qed, qed_goal and bind_thm store theorems in the database.
  1865 
  1866 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1867 a given theory (thms_of), or find out what theory a theorem was proved in
  1868 (theory_of_thm);
  1869 
  1870 * Bugs fixed in the inductive definition and datatype packages;
  1871 
  1872 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1873 and HOL_dup_cs obsolete;
  1874 
  1875 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1876 have been removed;
  1877 
  1878 * Simpler definition of function space in ZF;
  1879 
  1880 * new results about cardinal and ordinal arithmetic in ZF;
  1881 
  1882 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1883 types;
  1884 
  1885 
  1886 $Id$