NEWS
author berghofe
Tue Oct 16 16:48:30 2001 +0200 (2001-10-16)
changeset 11799 533a95523f61
parent 11797 1e29b79db3dc
child 11802 1d5f5d2427d2
permissions -rw-r--r--
Font metrics used for batch mode layout (without X11 connection).
     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 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    17 note that these symbols are currently unavailable in Proof General /
    18 X-Symbol;
    19 
    20 
    21 *** Isar ***
    22 
    23 * improved proof by cases and induction:
    24   - 'case' command admits impromptu naming of parameters (such as
    25     "case (Suc n)");
    26   - 'induct' method divinates rule instantiation from the inductive
    27     claim; no longer requires excessive ?P bindings for proper
    28     instantiation of cases;
    29   - 'induct' method properly enumerates all possibilities of set/type
    30     rules; as a consequence facts may be also passed through *type*
    31     rules without further ado;
    32   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    33   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    34   - moved induct/cases attributes to Pure, methods to Provers;
    35   - generic method setup instantiated for FOL and HOL;
    36 
    37 * Pure: renamed "antecedent" case to "rule_context";
    38 
    39 * Pure: added 'corollary' command;
    40 
    41 * Pure: fixed 'token_translation' command;
    42 
    43 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
    44 
    45 * HOL: 'recdef' now fails on unfinished automated proofs, use
    46 "(permissive)" option to recover old behavior;
    47 
    48 * HOL: 'inductive' now longer features separate (collective)
    49 attributes for 'intros';
    50 
    51 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
    52 
    53 
    54 *** HOL ***
    55 
    56 * HOL: moved over to sane numeral syntax; the new policy is as
    57 follows:
    58 
    59   - 0 and 1 are polymorphic constants, which are defined on any
    60   numeric type (nat, int, real etc.);
    61 
    62   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
    63   binary representation internally;
    64 
    65   - type nat has special constructor Suc, and generally prefers Suc 0
    66   over 1::nat and Suc (Suc 0) over 2::nat;
    67 
    68 This change may cause significant INCOMPATIBILITIES; here are some
    69 hints on converting existing sources:
    70 
    71   - due to the new "num" token, "-0" and "-1" etc. are now atomic
    72   entities, so expressions involving "-" (unary or binary minus) need
    73   to be spaced properly;
    74 
    75   - existing occurrences of "1" may need to be constraint "1::nat" or
    76   even replaced by Suc 0; similar for old "2";
    77 
    78   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
    79 
    80   - remove all special provisions on numerals in proofs;
    81 
    82 * HOL: linorder_less_split superseded by linorder_cases;
    83 
    84 * HOL: added "The" definite description operator; move Hilbert's "Eps"
    85 to peripheral theory "Hilbert_Choice";
    86 
    87 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
    88 in this (rare) case use:
    89 
    90   delSWrapper "split_all_tac"
    91   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
    92 
    93 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
    94 MAY FAIL;
    95 
    96 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
    97 Isabelle's type classes, ^ on functions and relations has too general
    98 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
    99 necessary to attach explicit type constraints;
   100 
   101 * HOL: syntax translations now work properly with numerals and records
   102 expressions;
   103 
   104 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   105 Florian Kammüller;
   106 
   107 * HOL: eliminated global items
   108 
   109   const "()" -> "Product_Type.Unity"
   110   type "unit" -> "Product_Type.unit"
   111 
   112 
   113 *** ZF ***
   114 
   115 * ZF: the integer library now covers quotients and remainders, with
   116 many laws relating division to addition, multiplication, etc.;
   117 
   118 
   119 *** General ***
   120 
   121 * Meta-level proof terms (by Stefan Berghofer), see also ref manual;
   122 
   123 * new token syntax "num" for plain numerals (without "#" of "xnum");
   124 potential INCOMPATIBILITY, since -0, -1 etc. are now separate tokens,
   125 so expressions involving minus need to be spaced properly;
   126 
   127 * Classical reasoner: renamed addaltern to addafter, addSaltern to
   128 addSafter;
   129 
   130 * syntax: support non-oriented infixes;
   131 
   132 * print modes "type_brackets" and "no_type_brackets" control output of
   133 nested => (types); the default behavior is "brackets";
   134 
   135 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   136 
   137 * system: Proof General keywords specification is now part of the
   138 Isabelle distribution (see etc/isar-keywords.el);
   139 
   140 * system: smart selection of Isabelle process versus Isabelle
   141 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   142 run both "isabelle" and "Isabelle" even if file names are badly
   143 damaged (executable inspects the case of the first letter of its own
   144 name); added separate "isabelle-process" and "isabelle-interface";
   145 
   146 
   147 
   148 New in Isabelle99-2 (February 2001)
   149 -----------------------------------
   150 
   151 *** Overview of INCOMPATIBILITIES ***
   152 
   153 * HOL: please note that theories in the Library and elsewhere often use the
   154 new-style (Isar) format; to refer to their theorems in an ML script you must
   155 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   156 
   157 * HOL: inductive package no longer splits induction rule aggressively,
   158 but only as far as specified by the introductions given; the old
   159 format may be recovered via ML function complete_split_rule or attribute
   160 'split_rule (complete)';
   161 
   162 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   163 gfp_Tarski to gfp_unfold;
   164 
   165 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   166 
   167 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   168 relation); infix "^^" has been renamed "``"; infix "``" has been
   169 renamed "`"; "univalent" has been renamed "single_valued";
   170 
   171 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   172 operation;
   173 
   174 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   175 
   176 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   177 
   178 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   179 consequence, it is no longer monotonic wrt. the local goal context
   180 (which is now passed through the inductive cases);
   181 
   182 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   183 \<gg> to \<ggreater>;
   184 
   185 
   186 *** Document preparation ***
   187 
   188 * \isabellestyle{NAME} selects version of Isabelle output (currently
   189 available: are "it" for near math-mode best-style output, "sl" for
   190 slanted text style, and "tt" for plain type-writer; if no
   191 \isabellestyle command is given, output is according to slanted
   192 type-writer);
   193 
   194 * support sub/super scripts (for single symbols only), input syntax is
   195 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   196 
   197 * some more standard symbols; see Appendix A of the system manual for
   198 the complete list of symbols defined in isabellesym.sty;
   199 
   200 * improved isabelle style files; more abstract symbol implementation
   201 (should now use \isamath{...} and \isatext{...} in custom symbol
   202 definitions);
   203 
   204 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   205 state; Note that presentation of goal states does not conform to
   206 actual human-readable proof documents.  Please do not include goal
   207 states into document output unless you really know what you are doing!
   208 
   209 * proper indentation of antiquoted output with proportional LaTeX
   210 fonts;
   211 
   212 * no_document ML operator temporarily disables LaTeX document
   213 generation;
   214 
   215 * isatool unsymbolize tunes sources for plain ASCII communication;
   216 
   217 
   218 *** Isar ***
   219 
   220 * Pure: Isar now suffers initial goal statements to contain unbound
   221 schematic variables (this does not conform to actual readable proof
   222 documents, due to unpredictable outcome and non-compositional proof
   223 checking); users who know what they are doing may use schematic goals
   224 for Prolog-style synthesis of proven results;
   225 
   226 * Pure: assumption method (an implicit finishing) now handles actual
   227 rules as well;
   228 
   229 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   230 initial goal, declare "that" only as Pure intro (only for single
   231 steps); the "that" rule assumption may now be involved in implicit
   232 finishing, thus ".." becomes a feasible for trivial obtains;
   233 
   234 * Pure: default proof step now includes 'intro_classes'; thus trivial
   235 instance proofs may be performed by "..";
   236 
   237 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   238 statements as well;
   239 
   240 * Pure: more robust selection of calculational rules;
   241 
   242 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   243 rule (as well as the assumption rule);
   244 
   245 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   246 lemmas, using the graph browser tool;
   247 
   248 * Pure: predict failure of "show" in interactive mode;
   249 
   250 * Pure: 'thms_containing' now takes actual terms as arguments;
   251 
   252 * HOL: improved method 'induct' --- now handles non-atomic goals
   253 (potential INCOMPATIBILITY); tuned error handling;
   254 
   255 * HOL: cases and induct rules now provide explicit hints about the
   256 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   257 any remaining facts are inserted into the goal verbatim;
   258 
   259 * HOL: local contexts (aka cases) may now contain term bindings as
   260 well; the 'cases' and 'induct' methods new provide a ?case binding for
   261 the result to be shown in each case;
   262 
   263 * HOL: added 'recdef_tc' command;
   264 
   265 * isatool convert assists in eliminating legacy ML scripts;
   266 
   267 
   268 *** HOL ***
   269 
   270 * HOL/Library: a collection of generic theories to be used together
   271 with main HOL; the theory loader path already includes this directory
   272 by default; the following existing theories have been moved here:
   273 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   274 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   275 
   276 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   277 modelling and verification task performed in Isabelle/HOL +
   278 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   279 
   280 * HOL/Algebra: special summation operator SUM no longer exists, it has
   281 been replaced by setsum; infix 'assoc' now has priority 50 (like
   282 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   283 'domain', this makes the theory consistent with mathematical
   284 literature;
   285 
   286 * HOL basics: added overloaded operations "inverse" and "divide"
   287 (infix "/"), syntax for generic "abs" operation, generic summation
   288 operator \<Sum>;
   289 
   290 * HOL/typedef: simplified package, provide more useful rules (see also
   291 HOL/subset.thy);
   292 
   293 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   294 now expressed as a proper nested rule (old-style tactic scripts may
   295 require atomize_strip_tac to cope with non-atomic premises);
   296 
   297 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   298 to "split_conv" (old name still available for compatibility);
   299 
   300 * HOL: improved concrete syntax for strings (e.g. allows translation
   301 rules with string literals);
   302 
   303 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   304 and Fleuriot's mechanization of analysis;
   305 
   306 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   307 
   308 
   309 *** CTT ***
   310 
   311 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   312 "lam" is displayed as TWO lambda-symbols
   313 
   314 * CTT: theory Main now available, containing everything (that is, Bool
   315 and Arith);
   316 
   317 
   318 *** General ***
   319 
   320 * Pure: the Simplifier has been implemented properly as a derived rule
   321 outside of the actual kernel (at last!); the overall performance
   322 penalty in practical applications is about 50%, while reliability of
   323 the Isabelle inference kernel has been greatly improved;
   324 
   325 * print modes "brackets" and "no_brackets" control output of nested =>
   326 (types) and ==> (props); the default behaviour is "brackets";
   327 
   328 * Provers: fast_tac (and friends) now handle actual object-logic rules
   329 as assumptions as well;
   330 
   331 * system: support Poly/ML 4.0;
   332 
   333 * system: isatool install handles KDE version 1 or 2;
   334 
   335 
   336 
   337 New in Isabelle99-1 (October 2000)
   338 ----------------------------------
   339 
   340 *** Overview of INCOMPATIBILITIES ***
   341 
   342 * HOL: simplification of natural numbers is much changed; to partly
   343 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   344 issue the following ML commands:
   345 
   346   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   347   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   348 
   349 * HOL: simplification no longer dives into case-expressions; this is
   350 controlled by "t.weak_case_cong" for each datatype t;
   351 
   352 * HOL: nat_less_induct renamed to less_induct;
   353 
   354 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   355 fixsome to patch .thy and .ML sources automatically;
   356 
   357   select_equality  -> some_equality
   358   select_eq_Ex     -> some_eq_ex
   359   selectI2EX       -> someI2_ex
   360   selectI2         -> someI2
   361   selectI          -> someI
   362   select1_equality -> some1_equality
   363   Eps_sym_eq       -> some_sym_eq_trivial
   364   Eps_eq           -> some_eq_trivial
   365 
   366 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   367 
   368 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   369 instead);
   370 
   371 * HOL: the recursion equations generated by 'recdef' are now called
   372 f.simps instead of f.rules;
   373 
   374 * HOL: qed_spec_mp now also handles bounded ALL as well;
   375 
   376 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   377 sometimes be needed;
   378 
   379 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   380 
   381 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   382 
   383 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   384 product is now "<*>" instead of "Times"; the lexicographic product is
   385 now "<*lex*>" instead of "**";
   386 
   387 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   388 of main HOL, but was unused); better use HOL's datatype package;
   389 
   390 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   391 the old syntax may be recovered as follows:
   392 
   393   syntax (symbols)
   394     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   395       (infixl "\\<oplus>" 100)
   396 
   397 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   398 
   399 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   400 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   401 internally;
   402 
   403 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   404 changed from A/r to A//r;
   405 
   406 * ZF: new treatment of arithmetic (nat & int) may break some old
   407 proofs;
   408 
   409 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   410 rulify -> rule_format, elimify -> elim_format, ...);
   411 
   412 * Isar/Provers: intro/elim/dest attributes changed; renamed
   413 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   414 should have to change intro!! to intro? only); replaced "delrule" by
   415 "rule del";
   416 
   417 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   418 
   419 * Provers: strengthened force_tac by using new first_best_tac;
   420 
   421 * LaTeX document preparation: several changes of isabelle.sty (see
   422 lib/texinputs);
   423 
   424 
   425 *** Document preparation ***
   426 
   427 * formal comments (text blocks etc.) in new-style theories may now
   428 contain antiquotations of thm/prop/term/typ/text to be presented
   429 according to latex print mode; concrete syntax is like this:
   430 @{term[show_types] "f(x) = a + x"};
   431 
   432 * isatool mkdir provides easy setup of Isabelle session directories,
   433 including proper document sources;
   434 
   435 * generated LaTeX sources are now deleted after successful run
   436 (isatool document -c); may retain a copy somewhere else via -D option
   437 of isatool usedir;
   438 
   439 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   440 style files, achieving self-contained LaTeX sources and simplifying
   441 LaTeX debugging;
   442 
   443 * old-style theories now produce (crude) LaTeX output as well;
   444 
   445 * browser info session directories are now self-contained (may be put
   446 on WWW server seperately); improved graphs of nested sessions; removed
   447 graph for 'all sessions';
   448 
   449 * several improvements in isabelle style files; \isabellestyle{it}
   450 produces fake math mode output; \isamarkupheader is now \section by
   451 default; see lib/texinputs/isabelle.sty etc.;
   452 
   453 
   454 *** Isar ***
   455 
   456 * Isar/Pure: local results and corresponding term bindings are now
   457 subject to Hindley-Milner polymorphism (similar to ML); this
   458 accommodates incremental type-inference very nicely;
   459 
   460 * Isar/Pure: new derived language element 'obtain' supports
   461 generalized existence reasoning;
   462 
   463 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   464 support accumulation of results, without applying any rules yet;
   465 useful to collect intermediate results without explicit name
   466 references, and for use with transitivity rules with more than 2
   467 premises;
   468 
   469 * Isar/Pure: scalable support for case-analysis type proofs: new
   470 'case' language element refers to local contexts symbolically, as
   471 produced by certain proof methods; internally, case names are attached
   472 to theorems as "tags";
   473 
   474 * Isar/Pure: theory command 'hide' removes declarations from
   475 class/type/const name spaces;
   476 
   477 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   478 indicate potential overloading;
   479 
   480 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   481 
   482 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   483 "{a,b,c}" instead of {a,b,c};
   484 
   485 * Isar/Pure now provides its own version of intro/elim/dest
   486 attributes; useful for building new logics, but beware of confusion
   487 with the version in Provers/classical;
   488 
   489 * Isar/Pure: the local context of (non-atomic) goals is provided via
   490 case name 'antecedent';
   491 
   492 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   493 to the current context is now done automatically);
   494 
   495 * Isar/Pure: theory command 'method_setup' provides a simple interface
   496 for definining proof methods in ML;
   497 
   498 * Isar/Provers: intro/elim/dest attributes changed; renamed
   499 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   500 most cases, one should have to change intro!! to intro? only);
   501 replaced "delrule" by "rule del";
   502 
   503 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   504 'symmetric' attribute (the latter supercedes [RS sym]);
   505 
   506 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   507 method modifier); 'simp' method: 'only:' modifier removes loopers as
   508 well (including splits);
   509 
   510 * Isar/Provers: Simplifier and Classical methods now support all kind
   511 of modifiers used in the past, including 'cong', 'iff', etc.
   512 
   513 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   514 of Simplifier and Classical reasoner);
   515 
   516 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   517 now support named cases; major packages (inductive, datatype, primrec,
   518 recdef) support case names and properly name parameters;
   519 
   520 * Isar/HOL: new transitivity rules for substitution in inequalities --
   521 monotonicity conditions are extracted to be proven at end of
   522 calculations;
   523 
   524 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   525 method anyway;
   526 
   527 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   528 split_if split_if_asm; datatype package provides theorems foo.splits =
   529 foo.split foo.split_asm for each datatype;
   530 
   531 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   532 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   533 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   534 use "(cases (simplified))" method in proper proof texts);
   535 
   536 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   537 
   538 * Isar: names of theorems etc. may be natural numbers as well;
   539 
   540 * Isar: 'pr' command: optional arguments for goals_limit and
   541 ProofContext.prems_limit; no longer prints theory contexts, but only
   542 proof states;
   543 
   544 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   545 additional print modes to be specified; e.g. "pr(latex)" will print
   546 proof state according to the Isabelle LaTeX style;
   547 
   548 * Isar: improved support for emulating tactic scripts, including proof
   549 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   550 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   551 (for HOL datatypes);
   552 
   553 * Isar: simplified (more robust) goal selection of proof methods: 1st
   554 goal, all goals, or explicit goal specifier (tactic emulation); thus
   555 'proof method scripts' have to be in depth-first order;
   556 
   557 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   558 
   559 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   560 should instead use individual commands for printing items
   561 (print_commands, print_methods etc.);
   562 
   563 * Isar: added 'nothing' --- the empty list of theorems;
   564 
   565 
   566 *** HOL ***
   567 
   568 * HOL/MicroJava: formalization of a fragment of Java, together with a
   569 corresponding virtual machine and a specification of its bytecode
   570 verifier and a lightweight bytecode verifier, including proofs of
   571 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   572 Cornelia Pusch (see also the homepage of project Bali at
   573 http://isabelle.in.tum.de/Bali/);
   574 
   575 * HOL/Algebra: new theory of rings and univariate polynomials, by
   576 Clemens Ballarin;
   577 
   578 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   579 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   580 Rasmussen;
   581 
   582 * HOL/Lattice: fundamental concepts of lattice theory and order
   583 structures, including duals, properties of bounds versus algebraic
   584 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   585 Theorem for complete lattices etc.; may also serve as a demonstration
   586 for abstract algebraic reasoning using axiomatic type classes, and
   587 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   588 
   589 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   590 von Oheimb;
   591 
   592 * HOL/IMPP: extension of IMP with local variables and mutually
   593 recursive procedures, by David von Oheimb;
   594 
   595 * HOL/Lambda: converted into new-style theory and document;
   596 
   597 * HOL/ex/Multiquote: example of multiple nested quotations and
   598 anti-quotations -- basically a generalized version of de-Bruijn
   599 representation; very useful in avoiding lifting of operations;
   600 
   601 * HOL/record: added general record equality rule to simpset; fixed
   602 select-update simplification procedure to handle extended records as
   603 well; admit "r" as field name;
   604 
   605 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   606 other numeric types and also as the identity of groups, rings, etc.;
   607 
   608 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   609 Types nat and int belong to this axclass;
   610 
   611 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   612    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   613    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   614   two terms #m*u and #n*u are replaced by #(m+n)*u
   615     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   616   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   617     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   618 
   619 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   620 powerful prover for predicate logic but knows nothing of clasets; see
   621 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   622 
   623 * HOL: new version of "case_tac" subsumes both boolean case split and
   624 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   625 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   626 
   627 * HOL: simplification no longer dives into case-expressions: only the
   628 selector expression is simplified, but not the remaining arms; to
   629 enable full simplification of case-expressions for datatype t, you may
   630 remove t.weak_case_cong from the simpset, either globally (Delcongs
   631 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   632 
   633 * HOL/recdef: the recursion equations generated by 'recdef' for
   634 function 'f' are now called f.simps instead of f.rules; if all
   635 termination conditions are proved automatically, these simplification
   636 rules are added to the simpset, as in primrec; rules may be named
   637 individually as well, resulting in a separate list of theorems for
   638 each equation;
   639 
   640 * HOL/While is a new theory that provides a while-combinator. It
   641 permits the definition of tail-recursive functions without the
   642 provision of a termination measure. The latter is necessary once the
   643 invariant proof rule for while is applied.
   644 
   645 * HOL: new (overloaded) notation for the set of elements below/above
   646 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   647 
   648 * HOL: theorems impI, allI, ballI bound as "strip";
   649 
   650 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   651 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   652 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   653 
   654 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   655 
   656 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   657 main HOL, but was unused);
   658 
   659 * HOL: fewer consts declared as global (e.g. have to refer to
   660 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   661 
   662 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   663 in case of overlap with user translations (e.g. judgements over
   664 tuples); (note that the underlying logical represenation is still
   665 bogus);
   666 
   667 
   668 *** ZF ***
   669 
   670 * ZF: simplification automatically cancels common terms in arithmetic
   671 expressions over nat and int;
   672 
   673 * ZF: new treatment of nat to minimize type-checking: all operators
   674 coerce their operands to a natural number using the function natify,
   675 making the algebraic laws unconditional;
   676 
   677 * ZF: as above, for int: operators coerce their operands to an integer
   678 using the function intify;
   679 
   680 * ZF: the integer library now contains many of the usual laws for the
   681 orderings, including $<=, and monotonicity laws for $+ and $*;
   682 
   683 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   684 simplification;
   685 
   686 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   687 to the simplifier and classical reasoner simultaneously;
   688 
   689 
   690 *** General ***
   691 
   692 * Provers: blast_tac now handles actual object-logic rules as
   693 assumptions; note that auto_tac uses blast_tac internally as well;
   694 
   695 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   696 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   697 
   698 * Provers: delrules now handles destruct rules as well (no longer need
   699 explicit make_elim);
   700 
   701 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   702   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   703 use instead the strong form,
   704   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   705 in HOL, FOL and ZF the function cla_make_elim will create such rules
   706 from destruct-rules;
   707 
   708 * Provers: Simplifier.easy_setup provides a fast path to basic
   709 Simplifier setup for new object-logics;
   710 
   711 * Pure: AST translation rules no longer require constant head on LHS;
   712 
   713 * Pure: improved name spaces: ambiguous output is qualified; support
   714 for hiding of names;
   715 
   716 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   717 XSYMBOL_HOME; no longer need to do manual configuration in most
   718 situations;
   719 
   720 * system: compression of ML heaps images may now be controlled via -c
   721 option of isabelle and isatool usedir (currently only observed by
   722 Poly/ML);
   723 
   724 * system: isatool installfonts may handle X-Symbol fonts as well (very
   725 useful for remote X11);
   726 
   727 * system: provide TAGS file for Isabelle sources;
   728 
   729 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   730 order;
   731 
   732 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   733 timing flag supersedes proof_timing and Toplevel.trace;
   734 
   735 * ML: new combinators |>> and |>>> for incremental transformations
   736 with secondary results (e.g. certain theory extensions):
   737 
   738 * ML: PureThy.add_defs gets additional argument to indicate potential
   739 overloading (usually false);
   740 
   741 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   742 results;
   743 
   744 
   745 
   746 New in Isabelle99 (October 1999)
   747 --------------------------------
   748 
   749 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   750 
   751 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   752 are no longer simplified.  (This allows the simplifier to unfold recursive
   753 functional programs.)  To restore the old behaviour, declare
   754 
   755     Delcongs [if_weak_cong];
   756 
   757 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   758 complement;
   759 
   760 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   761 
   762 * HOL/datatype: mutual_induct_tac no longer exists --
   763   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   764 
   765 * HOL/typedef: fixed type inference for representing set; type
   766 arguments now have to occur explicitly on the rhs as type constraints;
   767 
   768 * ZF: The con_defs part of an inductive definition may no longer refer
   769 to constants declared in the same theory;
   770 
   771 * HOL, ZF: the function mk_cases, generated by the inductive
   772 definition package, has lost an argument.  To simplify its result, it
   773 uses the default simpset instead of a supplied list of theorems.
   774 
   775 * HOL/List: the constructors of type list are now Nil and Cons;
   776 
   777 * Simplifier: the type of the infix ML functions
   778         setSSolver addSSolver setSolver addSolver
   779 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   780 for packaging solvers. A solver is created via
   781         mk_solver: string -> (thm list -> int -> tactic) -> solver
   782 where the string argument is only a comment.
   783 
   784 
   785 *** Proof tools ***
   786 
   787 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   788 decision procedure for linear arithmetic. Currently it is used for
   789 types `nat', `int', and `real' in HOL (see below); it can, should and
   790 will be instantiated for other types and logics as well.
   791 
   792 * The simplifier now accepts rewrite rules with flexible heads, eg
   793      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   794   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   795   matching.
   796 
   797 
   798 *** General ***
   799 
   800 * New Isabelle/Isar subsystem provides an alternative to traditional
   801 tactical theorem proving; together with the ProofGeneral/isar user
   802 interface it offers an interactive environment for developing human
   803 readable proof documents (Isar == Intelligible semi-automated
   804 reasoning); for further information see isatool doc isar-ref,
   805 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   806 
   807 * improved and simplified presentation of theories: better HTML markup
   808 (including colors), graph views in several sizes; isatool usedir now
   809 provides a proper interface for user theories (via -P option); actual
   810 document preparation based on (PDF)LaTeX is available as well (for
   811 new-style theories only); see isatool doc system for more information;
   812 
   813 * native support for Proof General, both for classic Isabelle and
   814 Isabelle/Isar;
   815 
   816 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   817 using the graph browser tool;
   818 
   819 * Isabelle manuals now also available as PDF;
   820 
   821 * theory loader rewritten from scratch (may not be fully
   822 bug-compatible); old loadpath variable has been replaced by show_path,
   823 add_path, del_path, reset_path functions; new operations such as
   824 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   825 isatool doc ref);
   826 
   827 * improved isatool install: option -k creates KDE application icon,
   828 option -p DIR installs standalone binaries;
   829 
   830 * added ML_PLATFORM setting (useful for cross-platform installations);
   831 more robust handling of platform specific ML images for SML/NJ;
   832 
   833 * the settings environment is now statically scoped, i.e. it is never
   834 created again in sub-processes invoked from isabelle, isatool, or
   835 Isabelle;
   836 
   837 * path element specification '~~' refers to '$ISABELLE_HOME';
   838 
   839 * in locales, the "assumes" and "defines" parts may be omitted if
   840 empty;
   841 
   842 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   843 long arrows);
   844 
   845 * new print_mode "HTML";
   846 
   847 * new flag show_tags controls display of tags of theorems (which are
   848 basically just comments that may be attached by some tools);
   849 
   850 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   851 mode and goal output format:
   852 
   853 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   854 244c244
   855 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   856 ---
   857 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   858 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   859 181c181
   860 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   861 ---
   862 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   863 
   864 * function bind_thms stores lists of theorems (cf. bind_thm);
   865 
   866 * new shorthand tactics ftac, eatac, datac, fatac;
   867 
   868 * qed (and friends) now accept "" as result name; in that case the
   869 theorem is not stored, but proper checks and presentation of the
   870 result still apply;
   871 
   872 * theorem database now also indexes constants "Trueprop", "all",
   873 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   874 
   875 
   876 *** HOL ***
   877 
   878 ** HOL arithmetic **
   879 
   880 * There are now decision procedures for linear arithmetic over nat and
   881 int:
   882 
   883 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   884 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   885 are treated as atomic; subformulae not involving type `nat' or `int'
   886 are ignored; quantified subformulae are ignored unless they are
   887 positive universal or negative existential. The tactic has to be
   888 invoked by hand and can be a little bit slow. In particular, the
   889 running time is exponential in the number of occurrences of `min' and
   890 `max', and `-' on `nat'.
   891 
   892 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   893 (negated) (in)equalities among the premises and the conclusion into
   894 account (i.e. no compound formulae) and does not know about `min' and
   895 `max', and `-' on `nat'. It is fast and is used automatically by the
   896 simplifier.
   897 
   898 NB: At the moment, these decision procedures do not cope with mixed
   899 nat/int formulae where the two parts interact, such as `m < n ==>
   900 int(m) < int(n)'.
   901 
   902 * HOL/Numeral provides a generic theory of numerals (encoded
   903 efficiently as bit strings); setup for types nat/int/real is in place;
   904 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   905 int, existing theories and proof scripts may require a few additional
   906 type constraints;
   907 
   908 * integer division and remainder can now be performed on constant
   909 arguments;
   910 
   911 * many properties of integer multiplication, division and remainder
   912 are now available;
   913 
   914 * An interface to the Stanford Validity Checker (SVC) is available through the
   915 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   916 are proved automatically.  SVC must be installed separately, and its results
   917 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   918 invocation of the underlying oracle).  For SVC see
   919   http://verify.stanford.edu/SVC
   920 
   921 * IsaMakefile: the HOL-Real target now builds an actual image;
   922 
   923 
   924 ** HOL misc **
   925 
   926 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   927 (in Isabelle/Isar) -- by Gertrud Bauer;
   928 
   929 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   930 analysis for assembly languages with subtypes;
   931 
   932 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   933 -- avoids syntactic ambiguities and treats state, transition, and
   934 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   935 changed syntax and (many) tactics;
   936 
   937 * HOL/inductive: Now also handles more general introduction rules such
   938   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   939   theorems are now maintained within the theory (maintained via the
   940   "mono" attribute);
   941 
   942 * HOL/datatype: Now also handles arbitrarily branching datatypes
   943   (using function types) such as
   944 
   945   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   946 
   947 * HOL/record: record_simproc (part of the default simpset) takes care
   948 of selectors applied to updated records; record_split_tac is no longer
   949 part of the default claset; update_defs may now be removed from the
   950 simpset in many cases; COMPATIBILITY: old behavior achieved by
   951 
   952   claset_ref () := claset() addSWrapper record_split_wrapper;
   953   Delsimprocs [record_simproc]
   954 
   955 * HOL/typedef: fixed type inference for representing set; type
   956 arguments now have to occur explicitly on the rhs as type constraints;
   957 
   958 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   959 names rather than an ML expression;
   960 
   961 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   962 supplied later.  Program schemes can be defined, such as
   963     "While B C s = (if B s then While B C (C s) else s)"
   964 where the well-founded relation can be chosen after B and C have been given.
   965 
   966 * HOL/List: the constructors of type list are now Nil and Cons;
   967 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   968 course, ML tools referring to List.list.op # etc. have to be adapted;
   969 
   970 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   971 disabled by default; run isabelle with option -m HOL to get back to
   972 the original Gordon/HOL-style output;
   973 
   974 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   975 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   976 
   977 * HOL basic syntax simplified (more orthogonal): all variants of
   978 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   979 Eps operator is provided as well: "SOME x. P[x]";
   980 
   981 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   982 
   983 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   984 thus available for user theories;
   985 
   986 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   987 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   988 time;
   989 
   990 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   991 several times and then mp;
   992 
   993 
   994 *** LK ***
   995 
   996 * the notation <<...>> is now available as a notation for sequences of
   997 formulas;
   998 
   999 * the simplifier is now installed
  1000 
  1001 * the axiom system has been generalized (thanks to Soren Heilmann)
  1002 
  1003 * the classical reasoner now has a default rule database
  1004 
  1005 
  1006 *** ZF ***
  1007 
  1008 * new primrec section allows primitive recursive functions to be given
  1009 directly (as in HOL) over datatypes and the natural numbers;
  1010 
  1011 * new tactics induct_tac and exhaust_tac for induction (or case
  1012 analysis) over datatypes and the natural numbers;
  1013 
  1014 * the datatype declaration of type T now defines the recursor T_rec;
  1015 
  1016 * simplification automatically does freeness reasoning for datatype
  1017 constructors;
  1018 
  1019 * automatic type-inference, with AddTCs command to insert new
  1020 type-checking rules;
  1021 
  1022 * datatype introduction rules are now added as Safe Introduction rules
  1023 to the claset;
  1024 
  1025 * the syntax "if P then x else y" is now available in addition to
  1026 if(P,x,y);
  1027 
  1028 
  1029 *** Internal programming interfaces ***
  1030 
  1031 * tuned simplifier trace output; new flag debug_simp;
  1032 
  1033 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1034 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1035 
  1036 * AxClass.axclass_tac lost the theory argument;
  1037 
  1038 * tuned current_goals_markers semantics: begin / end goal avoids
  1039 printing empty lines;
  1040 
  1041 * removed prs and prs_fn hook, which was broken because it did not
  1042 include \n in its semantics, forcing writeln to add one
  1043 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1044 string -> unit if you really want to output text without newline;
  1045 
  1046 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1047 plain output, interface builders may have to enable 'isabelle_font'
  1048 mode to get Isabelle font glyphs as before;
  1049 
  1050 * refined token_translation interface; INCOMPATIBILITY: output length
  1051 now of type real instead of int;
  1052 
  1053 * theory loader actions may be traced via new ThyInfo.add_hook
  1054 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1055 your own database of information attached to *whole* theories -- as
  1056 opposed to intra-theory data slots offered via TheoryDataFun;
  1057 
  1058 * proper handling of dangling sort hypotheses (at last!);
  1059 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1060 extra sort hypotheses that can be witnessed from the type signature;
  1061 the force_strip_shyps flag is gone, any remaining shyps are simply
  1062 left in the theorem (with a warning issued by strip_shyps_warning);
  1063 
  1064 
  1065 
  1066 New in Isabelle98-1 (October 1998)
  1067 ----------------------------------
  1068 
  1069 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1070 
  1071 * several changes of automated proof tools;
  1072 
  1073 * HOL: major changes to the inductive and datatype packages, including
  1074 some minor incompatibilities of theory syntax;
  1075 
  1076 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1077 called `inj_on';
  1078 
  1079 * HOL: removed duplicate thms in Arith:
  1080   less_imp_add_less  should be replaced by  trans_less_add1
  1081   le_imp_add_le      should be replaced by  trans_le_add1
  1082 
  1083 * HOL: unary minus is now overloaded (new type constraints may be
  1084 required);
  1085 
  1086 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1087 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1088 now taken as an integer constant.
  1089 
  1090 * Pure: ML function 'theory_of' renamed to 'theory';
  1091 
  1092 
  1093 *** Proof tools ***
  1094 
  1095 * Simplifier:
  1096   1. Asm_full_simp_tac is now more aggressive.
  1097      1. It will sometimes reorient premises if that increases their power to
  1098         simplify.
  1099      2. It does no longer proceed strictly from left to right but may also
  1100         rotate premises to achieve further simplification.
  1101      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1102      old Asm_full_simp_tac in that it does not rotate premises.
  1103   2. The simplifier now knows a little bit about nat-arithmetic.
  1104 
  1105 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1106 allows for selected deletion of wrappers, by introduction of names for
  1107 wrapper functionals.  This implies that addbefore, addSbefore,
  1108 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1109 and that adding two tactics with the same name overwrites the first
  1110 one (emitting a warning).
  1111   type wrapper = (int -> tactic) -> (int -> tactic)
  1112   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1113   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1114   delWrapper, delSWrapper: claset *  string            -> claset
  1115   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1116 
  1117 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1118 semantics; addbefore now affects only the unsafe part of step_tac
  1119 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1120 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1121 by Force_tac;
  1122 
  1123 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1124 compWrapper; added safe wrapper (and access functions for it);
  1125 
  1126 * HOL/split_all_tac is now much faster and fails if there is nothing
  1127 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1128 and the names of the automatically generated variables have changed.
  1129 split_all_tac has moved within claset() from unsafe wrappers to safe
  1130 wrappers, which means that !!-bound variables are split much more
  1131 aggressively, and safe_tac and clarify_tac now split such variables.
  1132 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1133 Note: the same holds for record_split_tac, which does the job of
  1134 split_all_tac for record fields.
  1135 
  1136 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1137 permanently to the default simpset using Addsplits just like
  1138 Addsimps. They can be removed via Delsplits just like
  1139 Delsimps. Lower-case versions are also available.
  1140 
  1141 * HOL/Simplifier: The rule split_if is now part of the default
  1142 simpset. This means that the simplifier will eliminate all occurrences
  1143 of if-then-else in the conclusion of a goal. To prevent this, you can
  1144 either remove split_if completely from the default simpset by
  1145 `Delsplits [split_if]' or remove it in a specific call of the
  1146 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1147 other case splitting rules to/from the default simpset: every datatype
  1148 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1149 t is the name of the datatype).
  1150 
  1151 * Classical reasoner / Simplifier combination: new force_tac (and
  1152 derivatives Force_tac, force) combines rewriting and classical
  1153 reasoning (and whatever other tools) similarly to auto_tac, but is
  1154 aimed to solve the given subgoal completely.
  1155 
  1156 
  1157 *** General ***
  1158 
  1159 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1160 and `goalw': the theory is no longer needed as an explicit argument -
  1161 the current theory context is used; assumptions are no longer returned
  1162 at the ML-level unless one of them starts with ==> or !!; it is
  1163 recommended to convert to these new commands using isatool fixgoal
  1164 (backup your sources first!);
  1165 
  1166 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1167 the current theory context, and 'theory' to lookup stored theories;
  1168 
  1169 * new theory section 'locale' for declaring constants, assumptions and
  1170 definitions that have local scope;
  1171 
  1172 * new theory section 'nonterminals' for purely syntactic types;
  1173 
  1174 * new theory section 'setup' for generic ML setup functions
  1175 (e.g. package initialization);
  1176 
  1177 * the distribution now includes Isabelle icons: see
  1178 lib/logo/isabelle-{small,tiny}.xpm;
  1179 
  1180 * isatool install - install binaries with absolute references to
  1181 ISABELLE_HOME/bin;
  1182 
  1183 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1184 
  1185 * print mode 'emacs' reserved for Isamode;
  1186 
  1187 * support multiple print (ast) translations per constant name;
  1188 
  1189 * theorems involving oracles are now printed with a suffixed [!];
  1190 
  1191 
  1192 *** HOL ***
  1193 
  1194 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1195 
  1196 * HOL/inductive package reorganized and improved: now supports mutual
  1197 definitions such as
  1198 
  1199   inductive EVEN ODD
  1200     intrs
  1201       null "0 : EVEN"
  1202       oddI "n : EVEN ==> Suc n : ODD"
  1203       evenI "n : ODD ==> Suc n : EVEN"
  1204 
  1205 new theorem list "elims" contains an elimination rule for each of the
  1206 recursive sets; inductive definitions now handle disjunctive premises
  1207 correctly (also ZF);
  1208 
  1209 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1210 "mutual_induct" no longer exists - the induction rule is always
  1211 contained in "induct";
  1212 
  1213 
  1214 * HOL/datatype package re-implemented and greatly improved: now
  1215 supports mutually recursive datatypes such as
  1216 
  1217   datatype
  1218     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1219             | SUM ('a aexp) ('a aexp)
  1220             | DIFF ('a aexp) ('a aexp)
  1221             | NUM 'a
  1222   and
  1223     'a bexp = LESS ('a aexp) ('a aexp)
  1224             | AND ('a bexp) ('a bexp)
  1225             | OR ('a bexp) ('a bexp)
  1226 
  1227 as well as indirectly recursive datatypes such as
  1228 
  1229   datatype
  1230     ('a, 'b) term = Var 'a
  1231                   | App 'b ((('a, 'b) term) list)
  1232 
  1233 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1234 induction on mutually / indirectly recursive datatypes.
  1235 
  1236 Primrec equations are now stored in theory and can be accessed via
  1237 <function_name>.simps.
  1238 
  1239 INCOMPATIBILITIES:
  1240 
  1241   - Theories using datatypes must now have theory Datatype as an
  1242     ancestor.
  1243   - The specific <typename>.induct_tac no longer exists - use the
  1244     generic induct_tac instead.
  1245   - natE has been renamed to nat.exhaust - use exhaust_tac
  1246     instead of res_inst_tac ... natE. Note that the variable
  1247     names in nat.exhaust differ from the names in natE, this
  1248     may cause some "fragile" proofs to fail.
  1249   - The theorems split_<typename>_case and split_<typename>_case_asm
  1250     have been renamed to <typename>.split and <typename>.split_asm.
  1251   - Since default sorts of type variables are now handled correctly,
  1252     some datatype definitions may have to be annotated with explicit
  1253     sort constraints.
  1254   - Primrec definitions no longer require function name and type
  1255     of recursive argument.
  1256 
  1257 Consider using isatool fixdatatype to adapt your theories and proof
  1258 scripts to the new package (backup your sources first!).
  1259 
  1260 
  1261 * HOL/record package: considerably improved implementation; now
  1262 includes concrete syntax for record types, terms, updates; theorems
  1263 for surjective pairing and splitting !!-bound record variables; proof
  1264 support is as follows:
  1265 
  1266   1) standard conversions (selectors or updates applied to record
  1267 constructor terms) are part of the standard simpset;
  1268 
  1269   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1270 made part of standard simpset and claset via addIffs;
  1271 
  1272   3) a tactic for record field splitting (record_split_tac) is part of
  1273 the standard claset (addSWrapper);
  1274 
  1275 To get a better idea about these rules you may retrieve them via
  1276 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1277 the name of your record type.
  1278 
  1279 The split tactic 3) conceptually simplifies by the following rule:
  1280 
  1281   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1282 
  1283 Thus any record variable that is bound by meta-all will automatically
  1284 blow up into some record constructor term, consequently the
  1285 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1286 solve record problems automatically.
  1287 
  1288 
  1289 * reorganized the main HOL image: HOL/Integ and String loaded by
  1290 default; theory Main includes everything;
  1291 
  1292 * automatic simplification of integer sums and comparisons, using cancellation;
  1293 
  1294 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1295 
  1296 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1297 
  1298 * many new identities for unions, intersections, set difference, etc.;
  1299 
  1300 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1301 called split_if, split_split, split_sum_case and split_nat_case (to go
  1302 with add/delsplits);
  1303 
  1304 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1305 (?x::unit) = (); this is made part of the default simpset, which COULD
  1306 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1307 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1308 unit_abs_eta_conv is added in order to counter the effect of
  1309 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1310 %u.f();
  1311 
  1312 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1313 makes more sense);
  1314 
  1315 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1316   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1317   disjointness reasoning but breaking a few old proofs.
  1318 
  1319 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1320 to 'converse' from 'inverse' (for compatibility with ZF and some
  1321 literature);
  1322 
  1323 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1324 the well-founded relation;
  1325 
  1326 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1327     Compl A.  The "Compl" syntax remains available as input syntax for this
  1328     release ONLY.
  1329 
  1330 * HOL/Update: new theory of function updates:
  1331     f(a:=b) == %x. if x=a then b else f x
  1332 may also be iterated as in f(a:=b,c:=d,...);
  1333 
  1334 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1335 
  1336 * HOL/List:
  1337   - new function list_update written xs[i:=v] that updates the i-th
  1338     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1339   - new function `upt' written [i..j(] which generates the list
  1340     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1341     bound write [i..j], which is a shorthand for [i..j+1(].
  1342   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1343 
  1344 * HOL/Arith:
  1345   - removed 'pred' (predecessor) function;
  1346   - generalized some theorems about n-1;
  1347   - many new laws about "div" and "mod";
  1348   - new laws about greatest common divisors (see theory ex/Primes);
  1349 
  1350 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1351 instead of "inverse";
  1352 
  1353 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1354   of the multiset ordering;
  1355 
  1356 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1357   (not included by default);
  1358 
  1359 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1360 
  1361 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1362   programs, i.e. different program variables may have different types.
  1363 
  1364 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1365   [previously, this check worked only if the rewrite rule was unconditional]
  1366   Now rew can involve either definitions or equalities (either == or =).
  1367 
  1368 
  1369 *** ZF ***
  1370 
  1371 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1372   only the theorems proved on ZF.ML;
  1373 
  1374 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1375   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1376   disjointness reasoning but breaking a few old proofs.
  1377 
  1378 * ZF/Update: new theory of function updates
  1379     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1380   may also be iterated as in f(a:=b,c:=d,...);
  1381 
  1382 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1383 
  1384 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1385   [previously, this check worked only if the rewrite rule was unconditional]
  1386   Now rew can involve either definitions or equalities (either == or =).
  1387 
  1388 * case_tac provided for compatibility with HOL
  1389     (like the old excluded_middle_tac, but with subgoals swapped)
  1390 
  1391 
  1392 *** Internal programming interfaces ***
  1393 
  1394 * Pure: several new basic modules made available for general use, see
  1395 also src/Pure/README;
  1396 
  1397 * improved the theory data mechanism to support encapsulation (data
  1398 kind name replaced by private Object.kind, acting as authorization
  1399 key); new type-safe user interface via functor TheoryDataFun; generic
  1400 print_data function becomes basically useless;
  1401 
  1402 * removed global_names compatibility flag -- all theory declarations
  1403 are qualified by default;
  1404 
  1405 * module Pure/Syntax now offers quote / antiquote translation
  1406 functions (useful for Hoare logic etc. with implicit dependencies);
  1407 see HOL/ex/Antiquote for an example use;
  1408 
  1409 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1410 cterm -> thm;
  1411 
  1412 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1413 subgoal;
  1414 
  1415 * Display.print_goals function moved to Locale.print_goals;
  1416 
  1417 * standard print function for goals supports current_goals_markers
  1418 variable for marking begin of proof, end of proof, start of goal; the
  1419 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1420 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1421 for example;
  1422 
  1423 
  1424 
  1425 New in Isabelle98 (January 1998)
  1426 --------------------------------
  1427 
  1428 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1429 
  1430 * changed lexical syntax of terms / types: dots made part of long
  1431 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1432 
  1433 * simpset (and claset) reference variable replaced by functions
  1434 simpset / simpset_ref;
  1435 
  1436 * no longer supports theory aliases (via merge) and non-trivial
  1437 implicit merge of thms' signatures;
  1438 
  1439 * most internal names of constants changed due to qualified names;
  1440 
  1441 * changed Pure/Sequence interface (see Pure/seq.ML);
  1442 
  1443 
  1444 *** General Changes ***
  1445 
  1446 * hierachically structured name spaces (for consts, types, axms, thms
  1447 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1448 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1449 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1450 long_names for fully qualified output names; NOTE: ML programs
  1451 (special tactics, packages etc.) referring to internal names may have
  1452 to be adapted to cope with fully qualified names; in case of severe
  1453 backward campatibility problems try setting 'global_names' at compile
  1454 time to have enrything declared within a flat name space; one may also
  1455 fine tune name declarations in theories via the 'global' and 'local'
  1456 section;
  1457 
  1458 * reimplemented the implicit simpset and claset using the new anytype
  1459 data filed in signatures; references simpset:simpset ref etc. are
  1460 replaced by functions simpset:unit->simpset and
  1461 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1462 to patch your ML files accordingly;
  1463 
  1464 * HTML output now includes theory graph data for display with Java
  1465 applet or isatool browser; data generated automatically via isatool
  1466 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1467 
  1468 * defs may now be conditional; improved rewrite_goals_tac to handle
  1469 conditional equations;
  1470 
  1471 * defs now admits additional type arguments, using TYPE('a) syntax;
  1472 
  1473 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1474 creates a new theory node; implicit merge of thms' signatures is
  1475 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1476 transfer:theory->thm->thm in (rare) cases;
  1477 
  1478 * improved handling of draft signatures / theories; draft thms (and
  1479 ctyps, cterms) are automatically promoted to real ones;
  1480 
  1481 * slightly changed interfaces for oracles: admit many per theory, named
  1482 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1483 
  1484 * print_goals: optional output of const types (set show_consts and
  1485 show_types);
  1486 
  1487 * improved output of warnings (###) and errors (***);
  1488 
  1489 * subgoal_tac displays a warning if the new subgoal has type variables;
  1490 
  1491 * removed old README and Makefiles;
  1492 
  1493 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1494 
  1495 * removed obsolete init_pps and init_database;
  1496 
  1497 * deleted the obsolete tactical STATE, which was declared by
  1498     fun STATE tacfun st = tacfun st st;
  1499 
  1500 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1501 (which abbreviates $HOME);
  1502 
  1503 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1504 use isatool fixseq to adapt your ML programs (this works for fully
  1505 qualified references to the Sequence structure only!);
  1506 
  1507 * use_thy no longer requires writable current directory; it always
  1508 reloads .ML *and* .thy file, if either one is out of date;
  1509 
  1510 
  1511 *** Classical Reasoner ***
  1512 
  1513 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1514 tactics that use classical reasoning to simplify a subgoal without
  1515 splitting it into several subgoals;
  1516 
  1517 * Safe_tac: like safe_tac but uses the default claset;
  1518 
  1519 
  1520 *** Simplifier ***
  1521 
  1522 * added simplification meta rules:
  1523     (asm_)(full_)simplify: simpset -> thm -> thm;
  1524 
  1525 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1526 logics (again);
  1527 
  1528 * added prems argument to simplification procedures;
  1529 
  1530 * HOL, FOL, ZF: added infix function `addsplits':
  1531   instead of `<simpset> setloop (split_tac <thms>)'
  1532   you can simply write `<simpset> addsplits <thms>'
  1533 
  1534 
  1535 *** Syntax ***
  1536 
  1537 * TYPE('a) syntax for type reflection terms;
  1538 
  1539 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1540 
  1541 * pretty printer: changed order of mixfix annotation preference (again!);
  1542 
  1543 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1544 
  1545 
  1546 *** HOL ***
  1547 
  1548 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1549   with `addloop' of the simplifier to faciliate case splitting in premises.
  1550 
  1551 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1552 
  1553 * HOL/Auth: new protocol proofs including some for the Internet
  1554   protocol TLS;
  1555 
  1556 * HOL/Map: new theory of `maps' a la VDM;
  1557 
  1558 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1559 cancelling out common nat summands from =, <, <= (in)equalities, or
  1560 differences; simplification procedures nat_cancel_factor for
  1561 cancelling common factor from =, <, <= (in)equalities over natural
  1562 sums; nat_cancel contains both kinds of procedures, it is installed by
  1563 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1564 
  1565 * HOL/simplifier: terms of the form
  1566   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1567   are rewritten to
  1568   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1569   and those of the form
  1570   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1571   are rewritten to
  1572   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1573 
  1574 * HOL/datatype
  1575   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1576 
  1577   P(t_case f1 ... fn x) =
  1578      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1579         ...
  1580        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1581      )
  1582 
  1583   and a theorem `split_t_case_asm' of the form
  1584 
  1585   P(t_case f1 ... fn x) =
  1586     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1587         ...
  1588        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1589      )
  1590   which can be added to a simpset via `addsplits'. The existing theorems
  1591   expand_list_case and expand_option_case have been renamed to
  1592   split_list_case and split_option_case.
  1593 
  1594 * HOL/Arithmetic:
  1595   - `pred n' is automatically converted to `n-1'.
  1596     Users are strongly encouraged not to use `pred' any longer,
  1597     because it will disappear altogether at some point.
  1598   - Users are strongly encouraged to write "0 < n" rather than
  1599     "n ~= 0". Theorems and proof tools have been modified towards this
  1600     `standard'.
  1601 
  1602 * HOL/Lists:
  1603   the function "set_of_list" has been renamed "set" (and its theorems too);
  1604   the function "nth" now takes its arguments in the reverse order and
  1605   has acquired the infix notation "!" as in "xs!n".
  1606 
  1607 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1608 
  1609 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1610   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1611 
  1612 * HOL/record: extensible records with schematic structural subtyping
  1613 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1614 still lacks various theorems and concrete record syntax;
  1615 
  1616 
  1617 *** HOLCF ***
  1618 
  1619 * removed "axioms" and "generated by" sections;
  1620 
  1621 * replaced "ops" section by extended "consts" section, which is capable of
  1622   handling the continuous function space "->" directly;
  1623 
  1624 * domain package:
  1625   . proves theorems immediately and stores them in the theory,
  1626   . creates hierachical name space,
  1627   . now uses normal mixfix annotations (instead of cinfix...),
  1628   . minor changes to some names and values (for consistency),
  1629   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1630   . separator between mutual domain defs: changed "," to "and",
  1631   . improved handling of sort constraints;  now they have to
  1632     appear on the left-hand side of the equations only;
  1633 
  1634 * fixed LAM <x,y,zs>.b syntax;
  1635 
  1636 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1637 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1638 
  1639 
  1640 *** FOL and ZF ***
  1641 
  1642 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1643   with `addloop' of the simplifier to faciliate case splitting in premises.
  1644 
  1645 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1646 in HOL, they strip ALL and --> from proved theorems;
  1647 
  1648 
  1649 
  1650 New in Isabelle94-8 (May 1997)
  1651 ------------------------------
  1652 
  1653 *** General Changes ***
  1654 
  1655 * new utilities to build / run / maintain Isabelle etc. (in parts
  1656 still somewhat experimental); old Makefiles etc. still functional;
  1657 
  1658 * new 'Isabelle System Manual';
  1659 
  1660 * INSTALL text, together with ./configure and ./build scripts;
  1661 
  1662 * reimplemented type inference for greater efficiency, better error
  1663 messages and clean internal interface;
  1664 
  1665 * prlim command for dealing with lots of subgoals (an easier way of
  1666 setting goals_limit);
  1667 
  1668 
  1669 *** Syntax ***
  1670 
  1671 * supports alternative (named) syntax tables (parser and pretty
  1672 printer); internal interface is provided by add_modesyntax(_i);
  1673 
  1674 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1675 be used in conjunction with the Isabelle symbol font; uses the
  1676 "symbols" syntax table;
  1677 
  1678 * added token_translation interface (may translate name tokens in
  1679 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1680 the current print_mode); IMPORTANT: user print translation functions
  1681 are responsible for marking newly introduced bounds
  1682 (Syntax.mark_boundT);
  1683 
  1684 * token translations for modes "xterm" and "xterm_color" that display
  1685 names in bold, underline etc. or colors (which requires a color
  1686 version of xterm);
  1687 
  1688 * infixes may now be declared with names independent of their syntax;
  1689 
  1690 * added typed_print_translation (like print_translation, but may
  1691 access type of constant);
  1692 
  1693 
  1694 *** Classical Reasoner ***
  1695 
  1696 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1697 some limitations.  Blast_tac...
  1698   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1699   + ignores elimination rules that don't have the correct format
  1700         (the conclusion MUST be a formula variable)
  1701   + ignores types, which can make HOL proofs fail
  1702   + rules must not require higher-order unification, e.g. apply_type in ZF
  1703     [message "Function Var's argument not a bound variable" relates to this]
  1704   + its proof strategy is more general but can actually be slower
  1705 
  1706 * substitution with equality assumptions no longer permutes other
  1707 assumptions;
  1708 
  1709 * minor changes in semantics of addafter (now called addaltern); renamed
  1710 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1711 (and access functions for it);
  1712 
  1713 * improved combination of classical reasoner and simplifier:
  1714   + functions for handling clasimpsets
  1715   + improvement of addss: now the simplifier is called _after_ the
  1716     safe steps.
  1717   + safe variant of addss called addSss: uses safe simplifications
  1718     _during_ the safe steps. It is more complete as it allows multiple
  1719     instantiations of unknowns (e.g. with slow_tac).
  1720 
  1721 *** Simplifier ***
  1722 
  1723 * added interface for simplification procedures (functions that
  1724 produce *proven* rewrite rules on the fly, depending on current
  1725 redex);
  1726 
  1727 * ordering on terms as parameter (used for ordered rewriting);
  1728 
  1729 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1730 
  1731 * the solver is now split into a safe and an unsafe part.
  1732 This should be invisible for the normal user, except that the
  1733 functions setsolver and addsolver have been renamed to setSolver and
  1734 addSolver; added safe_asm_full_simp_tac;
  1735 
  1736 
  1737 *** HOL ***
  1738 
  1739 * a generic induction tactic `induct_tac' which works for all datatypes and
  1740 also for type `nat';
  1741 
  1742 * a generic case distinction tactic `exhaust_tac' which works for all
  1743 datatypes and also for type `nat';
  1744 
  1745 * each datatype comes with a function `size';
  1746 
  1747 * patterns in case expressions allow tuple patterns as arguments to
  1748 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1749 
  1750 * primrec now also works with type nat;
  1751 
  1752 * recdef: a new declaration form, allows general recursive functions to be
  1753 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1754 
  1755 * the constant for negation has been renamed from "not" to "Not" to
  1756 harmonize with FOL, ZF, LK, etc.;
  1757 
  1758 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1759 infinite lists;
  1760 
  1761 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1762 
  1763 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1764 problems in commutative rings, using axiomatic type classes for + and *;
  1765 
  1766 * more examples in HOL/MiniML and HOL/Auth;
  1767 
  1768 * more default rewrite rules for quantifiers, union/intersection;
  1769 
  1770 * a new constant `arbitrary == @x.False';
  1771 
  1772 * HOLCF/IOA replaces old HOL/IOA;
  1773 
  1774 * HOLCF changes: derived all rules and arities
  1775   + axiomatic type classes instead of classes
  1776   + typedef instead of faking type definitions
  1777   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1778   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1779   + eliminated the types void, one, tr
  1780   + use unit lift and bool lift (with translations) instead of one and tr
  1781   + eliminated blift from Lift3.thy (use Def instead of blift)
  1782   all eliminated rules are derived as theorems --> no visible changes ;
  1783 
  1784 
  1785 *** ZF ***
  1786 
  1787 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1788 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1789 as ZF_cs addSIs [equalityI];
  1790 
  1791 
  1792 
  1793 New in Isabelle94-7 (November 96)
  1794 ---------------------------------
  1795 
  1796 * allowing negative levels (as offsets) in prlev and choplev;
  1797 
  1798 * super-linear speedup for large simplifications;
  1799 
  1800 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1801 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1802 FAIL); can suppress it using the command Delsimps (ex_simps @
  1803 all_simps); De Morgan laws are also now included, by default;
  1804 
  1805 * improved printing of ==>  :  ~:
  1806 
  1807 * new object-logic "Sequents" adds linear logic, while replacing LK
  1808 and Modal (thanks to Sara Kalvala);
  1809 
  1810 * HOL/Auth: correctness proofs for authentication protocols;
  1811 
  1812 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1813 examples on HOL/Auth);
  1814 
  1815 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1816 the rewriter and classical reasoner simultaneously;
  1817 
  1818 * function uresult no longer returns theorems in "standard" format;
  1819 regain previous version by: val uresult = standard o uresult;
  1820 
  1821 
  1822 
  1823 New in Isabelle94-6
  1824 -------------------
  1825 
  1826 * oracles -- these establish an interface between Isabelle and trusted
  1827 external reasoners, which may deliver results as theorems;
  1828 
  1829 * proof objects (in particular record all uses of oracles);
  1830 
  1831 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1832 
  1833 * "constdefs" section in theory files;
  1834 
  1835 * "primrec" section (HOL) no longer requires names;
  1836 
  1837 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1838 
  1839 
  1840 
  1841 New in Isabelle94-5
  1842 -------------------
  1843 
  1844 * reduced space requirements;
  1845 
  1846 * automatic HTML generation from theories;
  1847 
  1848 * theory files no longer require "..." (quotes) around most types;
  1849 
  1850 * new examples, including two proofs of the Church-Rosser theorem;
  1851 
  1852 * non-curried (1994) version of HOL is no longer distributed;
  1853 
  1854 
  1855 
  1856 New in Isabelle94-4
  1857 -------------------
  1858 
  1859 * greatly reduced space requirements;
  1860 
  1861 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1862 
  1863 * searchable theorem database (see the section "Retrieving theorems" on
  1864 page 8 of the Reference Manual);
  1865 
  1866 * new examples, including Grabczewski's monumental case study of the
  1867 Axiom of Choice;
  1868 
  1869 * The previous version of HOL renamed to Old_HOL;
  1870 
  1871 * The new version of HOL (previously called CHOL) uses a curried syntax
  1872 for functions.  Application looks like f a b instead of f(a,b);
  1873 
  1874 * Mutually recursive inductive definitions finally work in HOL;
  1875 
  1876 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1877 translates to the operator "split";
  1878 
  1879 
  1880 
  1881 New in Isabelle94-3
  1882 -------------------
  1883 
  1884 * new infix operator, addss, allowing the classical reasoner to
  1885 perform simplification at each step of its search.  Example:
  1886         fast_tac (cs addss ss)
  1887 
  1888 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1889 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1890 look like (a,b) instead of <a,b>;
  1891 
  1892 * PLEASE NOTE: CHOL will eventually replace HOL!
  1893 
  1894 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1895 It translates to the operator "split".  A new theory of integers is available;
  1896 
  1897 * In ZF, integer numerals now denote two's-complement binary integers.
  1898 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1899 
  1900 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1901 of the Axiom of Choice;
  1902 
  1903 
  1904 
  1905 New in Isabelle94-2
  1906 -------------------
  1907 
  1908 * Significantly faster resolution;
  1909 
  1910 * the different sections in a .thy file can now be mixed and repeated
  1911 freely;
  1912 
  1913 * Database of theorems for FOL, HOL and ZF.  New
  1914 commands including qed, qed_goal and bind_thm store theorems in the database.
  1915 
  1916 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1917 a given theory (thms_of), or find out what theory a theorem was proved in
  1918 (theory_of_thm);
  1919 
  1920 * Bugs fixed in the inductive definition and datatype packages;
  1921 
  1922 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1923 and HOL_dup_cs obsolete;
  1924 
  1925 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1926 have been removed;
  1927 
  1928 * Simpler definition of function space in ZF;
  1929 
  1930 * new results about cardinal and ordinal arithmetic in ZF;
  1931 
  1932 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1933 types;
  1934 
  1935 
  1936 $Id$