NEWS
author wenzelm
Wed Oct 17 18:50:49 2001 +0200 (2001-10-17)
changeset 11817 875ee0c20da2
parent 11814 1de4a3321976
child 11842 b903d3dabbe2
permissions -rw-r--r--
tuned;
     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 now 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: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
    83 (beware of argument permutation!);
    84 
    85 * HOL: linorder_less_split superseded by linorder_cases;
    86 
    87 * HOL: added "The" definite description operator; move Hilbert's "Eps"
    88 to peripheral theory "Hilbert_Choice";
    89 
    90 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
    91 in this (rare) case use:
    92 
    93   delSWrapper "split_all_tac"
    94   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
    95 
    96 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
    97 MAY FAIL;
    98 
    99 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   100 Isabelle's type classes, ^ on functions and relations has too general
   101 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   102 necessary to attach explicit type constraints;
   103 
   104 * HOL: syntax translations now work properly with numerals and records
   105 expressions;
   106 
   107 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   108 Florian Kammüller;
   109 
   110 * HOL: eliminated global items
   111 
   112   const "()" -> "Product_Type.Unity"
   113   type "unit" -> "Product_Type.unit"
   114 
   115 
   116 *** ZF ***
   117 
   118 * ZF: the integer library now covers quotients and remainders, with
   119 many laws relating division to addition, multiplication, etc.;
   120 
   121 
   122 *** General ***
   123 
   124 * kernel: meta-level proof terms (by Stefan Berghofer), see also ref
   125 manual;
   126 
   127 * classical reasoner: renamed addaltern to addafter, addSaltern to
   128 addSafter;
   129 
   130 * syntax: new token syntax "num" for plain numerals (without "#" of
   131 "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now separate
   132 tokens, so expressions involving minus need to be spaced properly;
   133 
   134 * syntax: support non-oriented infixes;
   135 
   136 * syntax: print modes "type_brackets" and "no_type_brackets" control
   137 output of nested => (types); the default behavior is "type_brackets";
   138 
   139 * syntax: builtin parse translation for "_constify" turns valued
   140 tokens into AST constants;
   141 
   142 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   143 
   144 * system: Proof General keywords specification is now part of the
   145 Isabelle distribution (see etc/isar-keywords.el);
   146 
   147 * system: smart selection of Isabelle process versus Isabelle
   148 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   149 run both "isabelle" and "Isabelle" even if file names are badly
   150 damaged (executable inspects the case of the first letter of its own
   151 name); added separate "isabelle-process" and "isabelle-interface";
   152 
   153 
   154 
   155 New in Isabelle99-2 (February 2001)
   156 -----------------------------------
   157 
   158 *** Overview of INCOMPATIBILITIES ***
   159 
   160 * HOL: please note that theories in the Library and elsewhere often use the
   161 new-style (Isar) format; to refer to their theorems in an ML script you must
   162 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   163 
   164 * HOL: inductive package no longer splits induction rule aggressively,
   165 but only as far as specified by the introductions given; the old
   166 format may be recovered via ML function complete_split_rule or attribute
   167 'split_rule (complete)';
   168 
   169 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   170 gfp_Tarski to gfp_unfold;
   171 
   172 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   173 
   174 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   175 relation); infix "^^" has been renamed "``"; infix "``" has been
   176 renamed "`"; "univalent" has been renamed "single_valued";
   177 
   178 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   179 operation;
   180 
   181 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   182 
   183 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   184 
   185 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   186 consequence, it is no longer monotonic wrt. the local goal context
   187 (which is now passed through the inductive cases);
   188 
   189 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   190 \<gg> to \<ggreater>;
   191 
   192 
   193 *** Document preparation ***
   194 
   195 * \isabellestyle{NAME} selects version of Isabelle output (currently
   196 available: are "it" for near math-mode best-style output, "sl" for
   197 slanted text style, and "tt" for plain type-writer; if no
   198 \isabellestyle command is given, output is according to slanted
   199 type-writer);
   200 
   201 * support sub/super scripts (for single symbols only), input syntax is
   202 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   203 
   204 * some more standard symbols; see Appendix A of the system manual for
   205 the complete list of symbols defined in isabellesym.sty;
   206 
   207 * improved isabelle style files; more abstract symbol implementation
   208 (should now use \isamath{...} and \isatext{...} in custom symbol
   209 definitions);
   210 
   211 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   212 state; Note that presentation of goal states does not conform to
   213 actual human-readable proof documents.  Please do not include goal
   214 states into document output unless you really know what you are doing!
   215 
   216 * proper indentation of antiquoted output with proportional LaTeX
   217 fonts;
   218 
   219 * no_document ML operator temporarily disables LaTeX document
   220 generation;
   221 
   222 * isatool unsymbolize tunes sources for plain ASCII communication;
   223 
   224 
   225 *** Isar ***
   226 
   227 * Pure: Isar now suffers initial goal statements to contain unbound
   228 schematic variables (this does not conform to actual readable proof
   229 documents, due to unpredictable outcome and non-compositional proof
   230 checking); users who know what they are doing may use schematic goals
   231 for Prolog-style synthesis of proven results;
   232 
   233 * Pure: assumption method (an implicit finishing) now handles actual
   234 rules as well;
   235 
   236 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   237 initial goal, declare "that" only as Pure intro (only for single
   238 steps); the "that" rule assumption may now be involved in implicit
   239 finishing, thus ".." becomes a feasible for trivial obtains;
   240 
   241 * Pure: default proof step now includes 'intro_classes'; thus trivial
   242 instance proofs may be performed by "..";
   243 
   244 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   245 statements as well;
   246 
   247 * Pure: more robust selection of calculational rules;
   248 
   249 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   250 rule (as well as the assumption rule);
   251 
   252 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   253 lemmas, using the graph browser tool;
   254 
   255 * Pure: predict failure of "show" in interactive mode;
   256 
   257 * Pure: 'thms_containing' now takes actual terms as arguments;
   258 
   259 * HOL: improved method 'induct' --- now handles non-atomic goals
   260 (potential INCOMPATIBILITY); tuned error handling;
   261 
   262 * HOL: cases and induct rules now provide explicit hints about the
   263 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   264 any remaining facts are inserted into the goal verbatim;
   265 
   266 * HOL: local contexts (aka cases) may now contain term bindings as
   267 well; the 'cases' and 'induct' methods new provide a ?case binding for
   268 the result to be shown in each case;
   269 
   270 * HOL: added 'recdef_tc' command;
   271 
   272 * isatool convert assists in eliminating legacy ML scripts;
   273 
   274 
   275 *** HOL ***
   276 
   277 * HOL/Library: a collection of generic theories to be used together
   278 with main HOL; the theory loader path already includes this directory
   279 by default; the following existing theories have been moved here:
   280 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   281 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   282 
   283 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   284 modelling and verification task performed in Isabelle/HOL +
   285 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   286 
   287 * HOL/Algebra: special summation operator SUM no longer exists, it has
   288 been replaced by setsum; infix 'assoc' now has priority 50 (like
   289 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   290 'domain', this makes the theory consistent with mathematical
   291 literature;
   292 
   293 * HOL basics: added overloaded operations "inverse" and "divide"
   294 (infix "/"), syntax for generic "abs" operation, generic summation
   295 operator \<Sum>;
   296 
   297 * HOL/typedef: simplified package, provide more useful rules (see also
   298 HOL/subset.thy);
   299 
   300 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   301 now expressed as a proper nested rule (old-style tactic scripts may
   302 require atomize_strip_tac to cope with non-atomic premises);
   303 
   304 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   305 to "split_conv" (old name still available for compatibility);
   306 
   307 * HOL: improved concrete syntax for strings (e.g. allows translation
   308 rules with string literals);
   309 
   310 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   311 and Fleuriot's mechanization of analysis;
   312 
   313 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   314 
   315 
   316 *** CTT ***
   317 
   318 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   319 "lam" is displayed as TWO lambda-symbols
   320 
   321 * CTT: theory Main now available, containing everything (that is, Bool
   322 and Arith);
   323 
   324 
   325 *** General ***
   326 
   327 * Pure: the Simplifier has been implemented properly as a derived rule
   328 outside of the actual kernel (at last!); the overall performance
   329 penalty in practical applications is about 50%, while reliability of
   330 the Isabelle inference kernel has been greatly improved;
   331 
   332 * print modes "brackets" and "no_brackets" control output of nested =>
   333 (types) and ==> (props); the default behaviour is "brackets";
   334 
   335 * Provers: fast_tac (and friends) now handle actual object-logic rules
   336 as assumptions as well;
   337 
   338 * system: support Poly/ML 4.0;
   339 
   340 * system: isatool install handles KDE version 1 or 2;
   341 
   342 
   343 
   344 New in Isabelle99-1 (October 2000)
   345 ----------------------------------
   346 
   347 *** Overview of INCOMPATIBILITIES ***
   348 
   349 * HOL: simplification of natural numbers is much changed; to partly
   350 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   351 issue the following ML commands:
   352 
   353   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   354   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   355 
   356 * HOL: simplification no longer dives into case-expressions; this is
   357 controlled by "t.weak_case_cong" for each datatype t;
   358 
   359 * HOL: nat_less_induct renamed to less_induct;
   360 
   361 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   362 fixsome to patch .thy and .ML sources automatically;
   363 
   364   select_equality  -> some_equality
   365   select_eq_Ex     -> some_eq_ex
   366   selectI2EX       -> someI2_ex
   367   selectI2         -> someI2
   368   selectI          -> someI
   369   select1_equality -> some1_equality
   370   Eps_sym_eq       -> some_sym_eq_trivial
   371   Eps_eq           -> some_eq_trivial
   372 
   373 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   374 
   375 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   376 instead);
   377 
   378 * HOL: the recursion equations generated by 'recdef' are now called
   379 f.simps instead of f.rules;
   380 
   381 * HOL: qed_spec_mp now also handles bounded ALL as well;
   382 
   383 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   384 sometimes be needed;
   385 
   386 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   387 
   388 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   389 
   390 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   391 product is now "<*>" instead of "Times"; the lexicographic product is
   392 now "<*lex*>" instead of "**";
   393 
   394 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   395 of main HOL, but was unused); better use HOL's datatype package;
   396 
   397 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   398 the old syntax may be recovered as follows:
   399 
   400   syntax (symbols)
   401     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   402       (infixl "\\<oplus>" 100)
   403 
   404 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   405 
   406 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   407 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   408 internally;
   409 
   410 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   411 changed from A/r to A//r;
   412 
   413 * ZF: new treatment of arithmetic (nat & int) may break some old
   414 proofs;
   415 
   416 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   417 rulify -> rule_format, elimify -> elim_format, ...);
   418 
   419 * Isar/Provers: intro/elim/dest attributes changed; renamed
   420 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   421 should have to change intro!! to intro? only); replaced "delrule" by
   422 "rule del";
   423 
   424 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   425 
   426 * Provers: strengthened force_tac by using new first_best_tac;
   427 
   428 * LaTeX document preparation: several changes of isabelle.sty (see
   429 lib/texinputs);
   430 
   431 
   432 *** Document preparation ***
   433 
   434 * formal comments (text blocks etc.) in new-style theories may now
   435 contain antiquotations of thm/prop/term/typ/text to be presented
   436 according to latex print mode; concrete syntax is like this:
   437 @{term[show_types] "f(x) = a + x"};
   438 
   439 * isatool mkdir provides easy setup of Isabelle session directories,
   440 including proper document sources;
   441 
   442 * generated LaTeX sources are now deleted after successful run
   443 (isatool document -c); may retain a copy somewhere else via -D option
   444 of isatool usedir;
   445 
   446 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   447 style files, achieving self-contained LaTeX sources and simplifying
   448 LaTeX debugging;
   449 
   450 * old-style theories now produce (crude) LaTeX output as well;
   451 
   452 * browser info session directories are now self-contained (may be put
   453 on WWW server seperately); improved graphs of nested sessions; removed
   454 graph for 'all sessions';
   455 
   456 * several improvements in isabelle style files; \isabellestyle{it}
   457 produces fake math mode output; \isamarkupheader is now \section by
   458 default; see lib/texinputs/isabelle.sty etc.;
   459 
   460 
   461 *** Isar ***
   462 
   463 * Isar/Pure: local results and corresponding term bindings are now
   464 subject to Hindley-Milner polymorphism (similar to ML); this
   465 accommodates incremental type-inference very nicely;
   466 
   467 * Isar/Pure: new derived language element 'obtain' supports
   468 generalized existence reasoning;
   469 
   470 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   471 support accumulation of results, without applying any rules yet;
   472 useful to collect intermediate results without explicit name
   473 references, and for use with transitivity rules with more than 2
   474 premises;
   475 
   476 * Isar/Pure: scalable support for case-analysis type proofs: new
   477 'case' language element refers to local contexts symbolically, as
   478 produced by certain proof methods; internally, case names are attached
   479 to theorems as "tags";
   480 
   481 * Isar/Pure: theory command 'hide' removes declarations from
   482 class/type/const name spaces;
   483 
   484 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   485 indicate potential overloading;
   486 
   487 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   488 
   489 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   490 "{a,b,c}" instead of {a,b,c};
   491 
   492 * Isar/Pure now provides its own version of intro/elim/dest
   493 attributes; useful for building new logics, but beware of confusion
   494 with the version in Provers/classical;
   495 
   496 * Isar/Pure: the local context of (non-atomic) goals is provided via
   497 case name 'antecedent';
   498 
   499 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   500 to the current context is now done automatically);
   501 
   502 * Isar/Pure: theory command 'method_setup' provides a simple interface
   503 for definining proof methods in ML;
   504 
   505 * Isar/Provers: intro/elim/dest attributes changed; renamed
   506 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   507 most cases, one should have to change intro!! to intro? only);
   508 replaced "delrule" by "rule del";
   509 
   510 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   511 'symmetric' attribute (the latter supercedes [RS sym]);
   512 
   513 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   514 method modifier); 'simp' method: 'only:' modifier removes loopers as
   515 well (including splits);
   516 
   517 * Isar/Provers: Simplifier and Classical methods now support all kind
   518 of modifiers used in the past, including 'cong', 'iff', etc.
   519 
   520 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   521 of Simplifier and Classical reasoner);
   522 
   523 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   524 now support named cases; major packages (inductive, datatype, primrec,
   525 recdef) support case names and properly name parameters;
   526 
   527 * Isar/HOL: new transitivity rules for substitution in inequalities --
   528 monotonicity conditions are extracted to be proven at end of
   529 calculations;
   530 
   531 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   532 method anyway;
   533 
   534 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   535 split_if split_if_asm; datatype package provides theorems foo.splits =
   536 foo.split foo.split_asm for each datatype;
   537 
   538 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   539 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   540 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   541 use "(cases (simplified))" method in proper proof texts);
   542 
   543 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   544 
   545 * Isar: names of theorems etc. may be natural numbers as well;
   546 
   547 * Isar: 'pr' command: optional arguments for goals_limit and
   548 ProofContext.prems_limit; no longer prints theory contexts, but only
   549 proof states;
   550 
   551 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   552 additional print modes to be specified; e.g. "pr(latex)" will print
   553 proof state according to the Isabelle LaTeX style;
   554 
   555 * Isar: improved support for emulating tactic scripts, including proof
   556 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   557 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   558 (for HOL datatypes);
   559 
   560 * Isar: simplified (more robust) goal selection of proof methods: 1st
   561 goal, all goals, or explicit goal specifier (tactic emulation); thus
   562 'proof method scripts' have to be in depth-first order;
   563 
   564 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   565 
   566 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   567 should instead use individual commands for printing items
   568 (print_commands, print_methods etc.);
   569 
   570 * Isar: added 'nothing' --- the empty list of theorems;
   571 
   572 
   573 *** HOL ***
   574 
   575 * HOL/MicroJava: formalization of a fragment of Java, together with a
   576 corresponding virtual machine and a specification of its bytecode
   577 verifier and a lightweight bytecode verifier, including proofs of
   578 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   579 Cornelia Pusch (see also the homepage of project Bali at
   580 http://isabelle.in.tum.de/Bali/);
   581 
   582 * HOL/Algebra: new theory of rings and univariate polynomials, by
   583 Clemens Ballarin;
   584 
   585 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   586 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   587 Rasmussen;
   588 
   589 * HOL/Lattice: fundamental concepts of lattice theory and order
   590 structures, including duals, properties of bounds versus algebraic
   591 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   592 Theorem for complete lattices etc.; may also serve as a demonstration
   593 for abstract algebraic reasoning using axiomatic type classes, and
   594 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   595 
   596 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   597 von Oheimb;
   598 
   599 * HOL/IMPP: extension of IMP with local variables and mutually
   600 recursive procedures, by David von Oheimb;
   601 
   602 * HOL/Lambda: converted into new-style theory and document;
   603 
   604 * HOL/ex/Multiquote: example of multiple nested quotations and
   605 anti-quotations -- basically a generalized version of de-Bruijn
   606 representation; very useful in avoiding lifting of operations;
   607 
   608 * HOL/record: added general record equality rule to simpset; fixed
   609 select-update simplification procedure to handle extended records as
   610 well; admit "r" as field name;
   611 
   612 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   613 other numeric types and also as the identity of groups, rings, etc.;
   614 
   615 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   616 Types nat and int belong to this axclass;
   617 
   618 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   619    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   620    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   621   two terms #m*u and #n*u are replaced by #(m+n)*u
   622     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   623   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   624     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   625 
   626 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   627 powerful prover for predicate logic but knows nothing of clasets; see
   628 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   629 
   630 * HOL: new version of "case_tac" subsumes both boolean case split and
   631 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   632 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   633 
   634 * HOL: simplification no longer dives into case-expressions: only the
   635 selector expression is simplified, but not the remaining arms; to
   636 enable full simplification of case-expressions for datatype t, you may
   637 remove t.weak_case_cong from the simpset, either globally (Delcongs
   638 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   639 
   640 * HOL/recdef: the recursion equations generated by 'recdef' for
   641 function 'f' are now called f.simps instead of f.rules; if all
   642 termination conditions are proved automatically, these simplification
   643 rules are added to the simpset, as in primrec; rules may be named
   644 individually as well, resulting in a separate list of theorems for
   645 each equation;
   646 
   647 * HOL/While is a new theory that provides a while-combinator. It
   648 permits the definition of tail-recursive functions without the
   649 provision of a termination measure. The latter is necessary once the
   650 invariant proof rule for while is applied.
   651 
   652 * HOL: new (overloaded) notation for the set of elements below/above
   653 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   654 
   655 * HOL: theorems impI, allI, ballI bound as "strip";
   656 
   657 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   658 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   659 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   660 
   661 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   662 
   663 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   664 main HOL, but was unused);
   665 
   666 * HOL: fewer consts declared as global (e.g. have to refer to
   667 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   668 
   669 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   670 in case of overlap with user translations (e.g. judgements over
   671 tuples); (note that the underlying logical represenation is still
   672 bogus);
   673 
   674 
   675 *** ZF ***
   676 
   677 * ZF: simplification automatically cancels common terms in arithmetic
   678 expressions over nat and int;
   679 
   680 * ZF: new treatment of nat to minimize type-checking: all operators
   681 coerce their operands to a natural number using the function natify,
   682 making the algebraic laws unconditional;
   683 
   684 * ZF: as above, for int: operators coerce their operands to an integer
   685 using the function intify;
   686 
   687 * ZF: the integer library now contains many of the usual laws for the
   688 orderings, including $<=, and monotonicity laws for $+ and $*;
   689 
   690 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   691 simplification;
   692 
   693 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   694 to the simplifier and classical reasoner simultaneously;
   695 
   696 
   697 *** General ***
   698 
   699 * Provers: blast_tac now handles actual object-logic rules as
   700 assumptions; note that auto_tac uses blast_tac internally as well;
   701 
   702 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   703 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   704 
   705 * Provers: delrules now handles destruct rules as well (no longer need
   706 explicit make_elim);
   707 
   708 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   709   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   710 use instead the strong form,
   711   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   712 in HOL, FOL and ZF the function cla_make_elim will create such rules
   713 from destruct-rules;
   714 
   715 * Provers: Simplifier.easy_setup provides a fast path to basic
   716 Simplifier setup for new object-logics;
   717 
   718 * Pure: AST translation rules no longer require constant head on LHS;
   719 
   720 * Pure: improved name spaces: ambiguous output is qualified; support
   721 for hiding of names;
   722 
   723 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   724 XSYMBOL_HOME; no longer need to do manual configuration in most
   725 situations;
   726 
   727 * system: compression of ML heaps images may now be controlled via -c
   728 option of isabelle and isatool usedir (currently only observed by
   729 Poly/ML);
   730 
   731 * system: isatool installfonts may handle X-Symbol fonts as well (very
   732 useful for remote X11);
   733 
   734 * system: provide TAGS file for Isabelle sources;
   735 
   736 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   737 order;
   738 
   739 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   740 timing flag supersedes proof_timing and Toplevel.trace;
   741 
   742 * ML: new combinators |>> and |>>> for incremental transformations
   743 with secondary results (e.g. certain theory extensions):
   744 
   745 * ML: PureThy.add_defs gets additional argument to indicate potential
   746 overloading (usually false);
   747 
   748 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   749 results;
   750 
   751 
   752 
   753 New in Isabelle99 (October 1999)
   754 --------------------------------
   755 
   756 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   757 
   758 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   759 are no longer simplified.  (This allows the simplifier to unfold recursive
   760 functional programs.)  To restore the old behaviour, declare
   761 
   762     Delcongs [if_weak_cong];
   763 
   764 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   765 complement;
   766 
   767 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   768 
   769 * HOL/datatype: mutual_induct_tac no longer exists --
   770   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   771 
   772 * HOL/typedef: fixed type inference for representing set; type
   773 arguments now have to occur explicitly on the rhs as type constraints;
   774 
   775 * ZF: The con_defs part of an inductive definition may no longer refer
   776 to constants declared in the same theory;
   777 
   778 * HOL, ZF: the function mk_cases, generated by the inductive
   779 definition package, has lost an argument.  To simplify its result, it
   780 uses the default simpset instead of a supplied list of theorems.
   781 
   782 * HOL/List: the constructors of type list are now Nil and Cons;
   783 
   784 * Simplifier: the type of the infix ML functions
   785         setSSolver addSSolver setSolver addSolver
   786 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   787 for packaging solvers. A solver is created via
   788         mk_solver: string -> (thm list -> int -> tactic) -> solver
   789 where the string argument is only a comment.
   790 
   791 
   792 *** Proof tools ***
   793 
   794 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   795 decision procedure for linear arithmetic. Currently it is used for
   796 types `nat', `int', and `real' in HOL (see below); it can, should and
   797 will be instantiated for other types and logics as well.
   798 
   799 * The simplifier now accepts rewrite rules with flexible heads, eg
   800      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   801   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   802   matching.
   803 
   804 
   805 *** General ***
   806 
   807 * New Isabelle/Isar subsystem provides an alternative to traditional
   808 tactical theorem proving; together with the ProofGeneral/isar user
   809 interface it offers an interactive environment for developing human
   810 readable proof documents (Isar == Intelligible semi-automated
   811 reasoning); for further information see isatool doc isar-ref,
   812 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   813 
   814 * improved and simplified presentation of theories: better HTML markup
   815 (including colors), graph views in several sizes; isatool usedir now
   816 provides a proper interface for user theories (via -P option); actual
   817 document preparation based on (PDF)LaTeX is available as well (for
   818 new-style theories only); see isatool doc system for more information;
   819 
   820 * native support for Proof General, both for classic Isabelle and
   821 Isabelle/Isar;
   822 
   823 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   824 using the graph browser tool;
   825 
   826 * Isabelle manuals now also available as PDF;
   827 
   828 * theory loader rewritten from scratch (may not be fully
   829 bug-compatible); old loadpath variable has been replaced by show_path,
   830 add_path, del_path, reset_path functions; new operations such as
   831 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   832 isatool doc ref);
   833 
   834 * improved isatool install: option -k creates KDE application icon,
   835 option -p DIR installs standalone binaries;
   836 
   837 * added ML_PLATFORM setting (useful for cross-platform installations);
   838 more robust handling of platform specific ML images for SML/NJ;
   839 
   840 * the settings environment is now statically scoped, i.e. it is never
   841 created again in sub-processes invoked from isabelle, isatool, or
   842 Isabelle;
   843 
   844 * path element specification '~~' refers to '$ISABELLE_HOME';
   845 
   846 * in locales, the "assumes" and "defines" parts may be omitted if
   847 empty;
   848 
   849 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   850 long arrows);
   851 
   852 * new print_mode "HTML";
   853 
   854 * new flag show_tags controls display of tags of theorems (which are
   855 basically just comments that may be attached by some tools);
   856 
   857 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   858 mode and goal output format:
   859 
   860 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   861 244c244
   862 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   863 ---
   864 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   865 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   866 181c181
   867 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   868 ---
   869 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   870 
   871 * function bind_thms stores lists of theorems (cf. bind_thm);
   872 
   873 * new shorthand tactics ftac, eatac, datac, fatac;
   874 
   875 * qed (and friends) now accept "" as result name; in that case the
   876 theorem is not stored, but proper checks and presentation of the
   877 result still apply;
   878 
   879 * theorem database now also indexes constants "Trueprop", "all",
   880 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   881 
   882 
   883 *** HOL ***
   884 
   885 ** HOL arithmetic **
   886 
   887 * There are now decision procedures for linear arithmetic over nat and
   888 int:
   889 
   890 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   891 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   892 are treated as atomic; subformulae not involving type `nat' or `int'
   893 are ignored; quantified subformulae are ignored unless they are
   894 positive universal or negative existential. The tactic has to be
   895 invoked by hand and can be a little bit slow. In particular, the
   896 running time is exponential in the number of occurrences of `min' and
   897 `max', and `-' on `nat'.
   898 
   899 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   900 (negated) (in)equalities among the premises and the conclusion into
   901 account (i.e. no compound formulae) and does not know about `min' and
   902 `max', and `-' on `nat'. It is fast and is used automatically by the
   903 simplifier.
   904 
   905 NB: At the moment, these decision procedures do not cope with mixed
   906 nat/int formulae where the two parts interact, such as `m < n ==>
   907 int(m) < int(n)'.
   908 
   909 * HOL/Numeral provides a generic theory of numerals (encoded
   910 efficiently as bit strings); setup for types nat/int/real is in place;
   911 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   912 int, existing theories and proof scripts may require a few additional
   913 type constraints;
   914 
   915 * integer division and remainder can now be performed on constant
   916 arguments;
   917 
   918 * many properties of integer multiplication, division and remainder
   919 are now available;
   920 
   921 * An interface to the Stanford Validity Checker (SVC) is available through the
   922 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   923 are proved automatically.  SVC must be installed separately, and its results
   924 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   925 invocation of the underlying oracle).  For SVC see
   926   http://verify.stanford.edu/SVC
   927 
   928 * IsaMakefile: the HOL-Real target now builds an actual image;
   929 
   930 
   931 ** HOL misc **
   932 
   933 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   934 (in Isabelle/Isar) -- by Gertrud Bauer;
   935 
   936 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   937 analysis for assembly languages with subtypes;
   938 
   939 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   940 -- avoids syntactic ambiguities and treats state, transition, and
   941 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   942 changed syntax and (many) tactics;
   943 
   944 * HOL/inductive: Now also handles more general introduction rules such
   945   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   946   theorems are now maintained within the theory (maintained via the
   947   "mono" attribute);
   948 
   949 * HOL/datatype: Now also handles arbitrarily branching datatypes
   950   (using function types) such as
   951 
   952   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   953 
   954 * HOL/record: record_simproc (part of the default simpset) takes care
   955 of selectors applied to updated records; record_split_tac is no longer
   956 part of the default claset; update_defs may now be removed from the
   957 simpset in many cases; COMPATIBILITY: old behavior achieved by
   958 
   959   claset_ref () := claset() addSWrapper record_split_wrapper;
   960   Delsimprocs [record_simproc]
   961 
   962 * HOL/typedef: fixed type inference for representing set; type
   963 arguments now have to occur explicitly on the rhs as type constraints;
   964 
   965 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   966 names rather than an ML expression;
   967 
   968 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   969 supplied later.  Program schemes can be defined, such as
   970     "While B C s = (if B s then While B C (C s) else s)"
   971 where the well-founded relation can be chosen after B and C have been given.
   972 
   973 * HOL/List: the constructors of type list are now Nil and Cons;
   974 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   975 course, ML tools referring to List.list.op # etc. have to be adapted;
   976 
   977 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   978 disabled by default; run isabelle with option -m HOL to get back to
   979 the original Gordon/HOL-style output;
   980 
   981 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   982 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   983 
   984 * HOL basic syntax simplified (more orthogonal): all variants of
   985 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   986 Eps operator is provided as well: "SOME x. P[x]";
   987 
   988 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   989 
   990 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   991 thus available for user theories;
   992 
   993 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   994 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   995 time;
   996 
   997 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   998 several times and then mp;
   999 
  1000 
  1001 *** LK ***
  1002 
  1003 * the notation <<...>> is now available as a notation for sequences of
  1004 formulas;
  1005 
  1006 * the simplifier is now installed
  1007 
  1008 * the axiom system has been generalized (thanks to Soren Heilmann)
  1009 
  1010 * the classical reasoner now has a default rule database
  1011 
  1012 
  1013 *** ZF ***
  1014 
  1015 * new primrec section allows primitive recursive functions to be given
  1016 directly (as in HOL) over datatypes and the natural numbers;
  1017 
  1018 * new tactics induct_tac and exhaust_tac for induction (or case
  1019 analysis) over datatypes and the natural numbers;
  1020 
  1021 * the datatype declaration of type T now defines the recursor T_rec;
  1022 
  1023 * simplification automatically does freeness reasoning for datatype
  1024 constructors;
  1025 
  1026 * automatic type-inference, with AddTCs command to insert new
  1027 type-checking rules;
  1028 
  1029 * datatype introduction rules are now added as Safe Introduction rules
  1030 to the claset;
  1031 
  1032 * the syntax "if P then x else y" is now available in addition to
  1033 if(P,x,y);
  1034 
  1035 
  1036 *** Internal programming interfaces ***
  1037 
  1038 * tuned simplifier trace output; new flag debug_simp;
  1039 
  1040 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1041 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1042 
  1043 * AxClass.axclass_tac lost the theory argument;
  1044 
  1045 * tuned current_goals_markers semantics: begin / end goal avoids
  1046 printing empty lines;
  1047 
  1048 * removed prs and prs_fn hook, which was broken because it did not
  1049 include \n in its semantics, forcing writeln to add one
  1050 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1051 string -> unit if you really want to output text without newline;
  1052 
  1053 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1054 plain output, interface builders may have to enable 'isabelle_font'
  1055 mode to get Isabelle font glyphs as before;
  1056 
  1057 * refined token_translation interface; INCOMPATIBILITY: output length
  1058 now of type real instead of int;
  1059 
  1060 * theory loader actions may be traced via new ThyInfo.add_hook
  1061 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1062 your own database of information attached to *whole* theories -- as
  1063 opposed to intra-theory data slots offered via TheoryDataFun;
  1064 
  1065 * proper handling of dangling sort hypotheses (at last!);
  1066 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1067 extra sort hypotheses that can be witnessed from the type signature;
  1068 the force_strip_shyps flag is gone, any remaining shyps are simply
  1069 left in the theorem (with a warning issued by strip_shyps_warning);
  1070 
  1071 
  1072 
  1073 New in Isabelle98-1 (October 1998)
  1074 ----------------------------------
  1075 
  1076 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1077 
  1078 * several changes of automated proof tools;
  1079 
  1080 * HOL: major changes to the inductive and datatype packages, including
  1081 some minor incompatibilities of theory syntax;
  1082 
  1083 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1084 called `inj_on';
  1085 
  1086 * HOL: removed duplicate thms in Arith:
  1087   less_imp_add_less  should be replaced by  trans_less_add1
  1088   le_imp_add_le      should be replaced by  trans_le_add1
  1089 
  1090 * HOL: unary minus is now overloaded (new type constraints may be
  1091 required);
  1092 
  1093 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1094 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1095 now taken as an integer constant.
  1096 
  1097 * Pure: ML function 'theory_of' renamed to 'theory';
  1098 
  1099 
  1100 *** Proof tools ***
  1101 
  1102 * Simplifier:
  1103   1. Asm_full_simp_tac is now more aggressive.
  1104      1. It will sometimes reorient premises if that increases their power to
  1105         simplify.
  1106      2. It does no longer proceed strictly from left to right but may also
  1107         rotate premises to achieve further simplification.
  1108      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1109      old Asm_full_simp_tac in that it does not rotate premises.
  1110   2. The simplifier now knows a little bit about nat-arithmetic.
  1111 
  1112 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1113 allows for selected deletion of wrappers, by introduction of names for
  1114 wrapper functionals.  This implies that addbefore, addSbefore,
  1115 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1116 and that adding two tactics with the same name overwrites the first
  1117 one (emitting a warning).
  1118   type wrapper = (int -> tactic) -> (int -> tactic)
  1119   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1120   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1121   delWrapper, delSWrapper: claset *  string            -> claset
  1122   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1123 
  1124 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1125 semantics; addbefore now affects only the unsafe part of step_tac
  1126 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1127 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1128 by Force_tac;
  1129 
  1130 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1131 compWrapper; added safe wrapper (and access functions for it);
  1132 
  1133 * HOL/split_all_tac is now much faster and fails if there is nothing
  1134 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1135 and the names of the automatically generated variables have changed.
  1136 split_all_tac has moved within claset() from unsafe wrappers to safe
  1137 wrappers, which means that !!-bound variables are split much more
  1138 aggressively, and safe_tac and clarify_tac now split such variables.
  1139 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1140 Note: the same holds for record_split_tac, which does the job of
  1141 split_all_tac for record fields.
  1142 
  1143 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1144 permanently to the default simpset using Addsplits just like
  1145 Addsimps. They can be removed via Delsplits just like
  1146 Delsimps. Lower-case versions are also available.
  1147 
  1148 * HOL/Simplifier: The rule split_if is now part of the default
  1149 simpset. This means that the simplifier will eliminate all occurrences
  1150 of if-then-else in the conclusion of a goal. To prevent this, you can
  1151 either remove split_if completely from the default simpset by
  1152 `Delsplits [split_if]' or remove it in a specific call of the
  1153 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1154 other case splitting rules to/from the default simpset: every datatype
  1155 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1156 t is the name of the datatype).
  1157 
  1158 * Classical reasoner / Simplifier combination: new force_tac (and
  1159 derivatives Force_tac, force) combines rewriting and classical
  1160 reasoning (and whatever other tools) similarly to auto_tac, but is
  1161 aimed to solve the given subgoal completely.
  1162 
  1163 
  1164 *** General ***
  1165 
  1166 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1167 and `goalw': the theory is no longer needed as an explicit argument -
  1168 the current theory context is used; assumptions are no longer returned
  1169 at the ML-level unless one of them starts with ==> or !!; it is
  1170 recommended to convert to these new commands using isatool fixgoal
  1171 (backup your sources first!);
  1172 
  1173 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1174 the current theory context, and 'theory' to lookup stored theories;
  1175 
  1176 * new theory section 'locale' for declaring constants, assumptions and
  1177 definitions that have local scope;
  1178 
  1179 * new theory section 'nonterminals' for purely syntactic types;
  1180 
  1181 * new theory section 'setup' for generic ML setup functions
  1182 (e.g. package initialization);
  1183 
  1184 * the distribution now includes Isabelle icons: see
  1185 lib/logo/isabelle-{small,tiny}.xpm;
  1186 
  1187 * isatool install - install binaries with absolute references to
  1188 ISABELLE_HOME/bin;
  1189 
  1190 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1191 
  1192 * print mode 'emacs' reserved for Isamode;
  1193 
  1194 * support multiple print (ast) translations per constant name;
  1195 
  1196 * theorems involving oracles are now printed with a suffixed [!];
  1197 
  1198 
  1199 *** HOL ***
  1200 
  1201 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1202 
  1203 * HOL/inductive package reorganized and improved: now supports mutual
  1204 definitions such as
  1205 
  1206   inductive EVEN ODD
  1207     intrs
  1208       null "0 : EVEN"
  1209       oddI "n : EVEN ==> Suc n : ODD"
  1210       evenI "n : ODD ==> Suc n : EVEN"
  1211 
  1212 new theorem list "elims" contains an elimination rule for each of the
  1213 recursive sets; inductive definitions now handle disjunctive premises
  1214 correctly (also ZF);
  1215 
  1216 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1217 "mutual_induct" no longer exists - the induction rule is always
  1218 contained in "induct";
  1219 
  1220 
  1221 * HOL/datatype package re-implemented and greatly improved: now
  1222 supports mutually recursive datatypes such as
  1223 
  1224   datatype
  1225     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1226             | SUM ('a aexp) ('a aexp)
  1227             | DIFF ('a aexp) ('a aexp)
  1228             | NUM 'a
  1229   and
  1230     'a bexp = LESS ('a aexp) ('a aexp)
  1231             | AND ('a bexp) ('a bexp)
  1232             | OR ('a bexp) ('a bexp)
  1233 
  1234 as well as indirectly recursive datatypes such as
  1235 
  1236   datatype
  1237     ('a, 'b) term = Var 'a
  1238                   | App 'b ((('a, 'b) term) list)
  1239 
  1240 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1241 induction on mutually / indirectly recursive datatypes.
  1242 
  1243 Primrec equations are now stored in theory and can be accessed via
  1244 <function_name>.simps.
  1245 
  1246 INCOMPATIBILITIES:
  1247 
  1248   - Theories using datatypes must now have theory Datatype as an
  1249     ancestor.
  1250   - The specific <typename>.induct_tac no longer exists - use the
  1251     generic induct_tac instead.
  1252   - natE has been renamed to nat.exhaust - use exhaust_tac
  1253     instead of res_inst_tac ... natE. Note that the variable
  1254     names in nat.exhaust differ from the names in natE, this
  1255     may cause some "fragile" proofs to fail.
  1256   - The theorems split_<typename>_case and split_<typename>_case_asm
  1257     have been renamed to <typename>.split and <typename>.split_asm.
  1258   - Since default sorts of type variables are now handled correctly,
  1259     some datatype definitions may have to be annotated with explicit
  1260     sort constraints.
  1261   - Primrec definitions no longer require function name and type
  1262     of recursive argument.
  1263 
  1264 Consider using isatool fixdatatype to adapt your theories and proof
  1265 scripts to the new package (backup your sources first!).
  1266 
  1267 
  1268 * HOL/record package: considerably improved implementation; now
  1269 includes concrete syntax for record types, terms, updates; theorems
  1270 for surjective pairing and splitting !!-bound record variables; proof
  1271 support is as follows:
  1272 
  1273   1) standard conversions (selectors or updates applied to record
  1274 constructor terms) are part of the standard simpset;
  1275 
  1276   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1277 made part of standard simpset and claset via addIffs;
  1278 
  1279   3) a tactic for record field splitting (record_split_tac) is part of
  1280 the standard claset (addSWrapper);
  1281 
  1282 To get a better idea about these rules you may retrieve them via
  1283 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1284 the name of your record type.
  1285 
  1286 The split tactic 3) conceptually simplifies by the following rule:
  1287 
  1288   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1289 
  1290 Thus any record variable that is bound by meta-all will automatically
  1291 blow up into some record constructor term, consequently the
  1292 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1293 solve record problems automatically.
  1294 
  1295 
  1296 * reorganized the main HOL image: HOL/Integ and String loaded by
  1297 default; theory Main includes everything;
  1298 
  1299 * automatic simplification of integer sums and comparisons, using cancellation;
  1300 
  1301 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1302 
  1303 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1304 
  1305 * many new identities for unions, intersections, set difference, etc.;
  1306 
  1307 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1308 called split_if, split_split, split_sum_case and split_nat_case (to go
  1309 with add/delsplits);
  1310 
  1311 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1312 (?x::unit) = (); this is made part of the default simpset, which COULD
  1313 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1314 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1315 unit_abs_eta_conv is added in order to counter the effect of
  1316 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1317 %u.f();
  1318 
  1319 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1320 makes more sense);
  1321 
  1322 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1323   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1324   disjointness reasoning but breaking a few old proofs.
  1325 
  1326 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1327 to 'converse' from 'inverse' (for compatibility with ZF and some
  1328 literature);
  1329 
  1330 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1331 the well-founded relation;
  1332 
  1333 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1334     Compl A.  The "Compl" syntax remains available as input syntax for this
  1335     release ONLY.
  1336 
  1337 * HOL/Update: new theory of function updates:
  1338     f(a:=b) == %x. if x=a then b else f x
  1339 may also be iterated as in f(a:=b,c:=d,...);
  1340 
  1341 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1342 
  1343 * HOL/List:
  1344   - new function list_update written xs[i:=v] that updates the i-th
  1345     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1346   - new function `upt' written [i..j(] which generates the list
  1347     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1348     bound write [i..j], which is a shorthand for [i..j+1(].
  1349   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1350 
  1351 * HOL/Arith:
  1352   - removed 'pred' (predecessor) function;
  1353   - generalized some theorems about n-1;
  1354   - many new laws about "div" and "mod";
  1355   - new laws about greatest common divisors (see theory ex/Primes);
  1356 
  1357 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1358 instead of "inverse";
  1359 
  1360 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1361   of the multiset ordering;
  1362 
  1363 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1364   (not included by default);
  1365 
  1366 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1367 
  1368 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1369   programs, i.e. different program variables may have different types.
  1370 
  1371 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1372   [previously, this check worked only if the rewrite rule was unconditional]
  1373   Now rew can involve either definitions or equalities (either == or =).
  1374 
  1375 
  1376 *** ZF ***
  1377 
  1378 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1379   only the theorems proved on ZF.ML;
  1380 
  1381 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1382   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1383   disjointness reasoning but breaking a few old proofs.
  1384 
  1385 * ZF/Update: new theory of function updates
  1386     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1387   may also be iterated as in f(a:=b,c:=d,...);
  1388 
  1389 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1390 
  1391 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1392   [previously, this check worked only if the rewrite rule was unconditional]
  1393   Now rew can involve either definitions or equalities (either == or =).
  1394 
  1395 * case_tac provided for compatibility with HOL
  1396     (like the old excluded_middle_tac, but with subgoals swapped)
  1397 
  1398 
  1399 *** Internal programming interfaces ***
  1400 
  1401 * Pure: several new basic modules made available for general use, see
  1402 also src/Pure/README;
  1403 
  1404 * improved the theory data mechanism to support encapsulation (data
  1405 kind name replaced by private Object.kind, acting as authorization
  1406 key); new type-safe user interface via functor TheoryDataFun; generic
  1407 print_data function becomes basically useless;
  1408 
  1409 * removed global_names compatibility flag -- all theory declarations
  1410 are qualified by default;
  1411 
  1412 * module Pure/Syntax now offers quote / antiquote translation
  1413 functions (useful for Hoare logic etc. with implicit dependencies);
  1414 see HOL/ex/Antiquote for an example use;
  1415 
  1416 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1417 cterm -> thm;
  1418 
  1419 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1420 subgoal;
  1421 
  1422 * Display.print_goals function moved to Locale.print_goals;
  1423 
  1424 * standard print function for goals supports current_goals_markers
  1425 variable for marking begin of proof, end of proof, start of goal; the
  1426 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1427 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1428 for example;
  1429 
  1430 
  1431 
  1432 New in Isabelle98 (January 1998)
  1433 --------------------------------
  1434 
  1435 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1436 
  1437 * changed lexical syntax of terms / types: dots made part of long
  1438 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1439 
  1440 * simpset (and claset) reference variable replaced by functions
  1441 simpset / simpset_ref;
  1442 
  1443 * no longer supports theory aliases (via merge) and non-trivial
  1444 implicit merge of thms' signatures;
  1445 
  1446 * most internal names of constants changed due to qualified names;
  1447 
  1448 * changed Pure/Sequence interface (see Pure/seq.ML);
  1449 
  1450 
  1451 *** General Changes ***
  1452 
  1453 * hierachically structured name spaces (for consts, types, axms, thms
  1454 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1455 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1456 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1457 long_names for fully qualified output names; NOTE: ML programs
  1458 (special tactics, packages etc.) referring to internal names may have
  1459 to be adapted to cope with fully qualified names; in case of severe
  1460 backward campatibility problems try setting 'global_names' at compile
  1461 time to have enrything declared within a flat name space; one may also
  1462 fine tune name declarations in theories via the 'global' and 'local'
  1463 section;
  1464 
  1465 * reimplemented the implicit simpset and claset using the new anytype
  1466 data filed in signatures; references simpset:simpset ref etc. are
  1467 replaced by functions simpset:unit->simpset and
  1468 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1469 to patch your ML files accordingly;
  1470 
  1471 * HTML output now includes theory graph data for display with Java
  1472 applet or isatool browser; data generated automatically via isatool
  1473 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1474 
  1475 * defs may now be conditional; improved rewrite_goals_tac to handle
  1476 conditional equations;
  1477 
  1478 * defs now admits additional type arguments, using TYPE('a) syntax;
  1479 
  1480 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1481 creates a new theory node; implicit merge of thms' signatures is
  1482 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1483 transfer:theory->thm->thm in (rare) cases;
  1484 
  1485 * improved handling of draft signatures / theories; draft thms (and
  1486 ctyps, cterms) are automatically promoted to real ones;
  1487 
  1488 * slightly changed interfaces for oracles: admit many per theory, named
  1489 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1490 
  1491 * print_goals: optional output of const types (set show_consts and
  1492 show_types);
  1493 
  1494 * improved output of warnings (###) and errors (***);
  1495 
  1496 * subgoal_tac displays a warning if the new subgoal has type variables;
  1497 
  1498 * removed old README and Makefiles;
  1499 
  1500 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1501 
  1502 * removed obsolete init_pps and init_database;
  1503 
  1504 * deleted the obsolete tactical STATE, which was declared by
  1505     fun STATE tacfun st = tacfun st st;
  1506 
  1507 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1508 (which abbreviates $HOME);
  1509 
  1510 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1511 use isatool fixseq to adapt your ML programs (this works for fully
  1512 qualified references to the Sequence structure only!);
  1513 
  1514 * use_thy no longer requires writable current directory; it always
  1515 reloads .ML *and* .thy file, if either one is out of date;
  1516 
  1517 
  1518 *** Classical Reasoner ***
  1519 
  1520 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1521 tactics that use classical reasoning to simplify a subgoal without
  1522 splitting it into several subgoals;
  1523 
  1524 * Safe_tac: like safe_tac but uses the default claset;
  1525 
  1526 
  1527 *** Simplifier ***
  1528 
  1529 * added simplification meta rules:
  1530     (asm_)(full_)simplify: simpset -> thm -> thm;
  1531 
  1532 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1533 logics (again);
  1534 
  1535 * added prems argument to simplification procedures;
  1536 
  1537 * HOL, FOL, ZF: added infix function `addsplits':
  1538   instead of `<simpset> setloop (split_tac <thms>)'
  1539   you can simply write `<simpset> addsplits <thms>'
  1540 
  1541 
  1542 *** Syntax ***
  1543 
  1544 * TYPE('a) syntax for type reflection terms;
  1545 
  1546 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1547 
  1548 * pretty printer: changed order of mixfix annotation preference (again!);
  1549 
  1550 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1551 
  1552 
  1553 *** HOL ***
  1554 
  1555 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1556   with `addloop' of the simplifier to faciliate case splitting in premises.
  1557 
  1558 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1559 
  1560 * HOL/Auth: new protocol proofs including some for the Internet
  1561   protocol TLS;
  1562 
  1563 * HOL/Map: new theory of `maps' a la VDM;
  1564 
  1565 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1566 cancelling out common nat summands from =, <, <= (in)equalities, or
  1567 differences; simplification procedures nat_cancel_factor for
  1568 cancelling common factor from =, <, <= (in)equalities over natural
  1569 sums; nat_cancel contains both kinds of procedures, it is installed by
  1570 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1571 
  1572 * HOL/simplifier: terms of the form
  1573   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1574   are rewritten to
  1575   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1576   and those of the form
  1577   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1578   are rewritten to
  1579   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1580 
  1581 * HOL/datatype
  1582   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1583 
  1584   P(t_case f1 ... fn x) =
  1585      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1586         ...
  1587        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1588      )
  1589 
  1590   and a theorem `split_t_case_asm' of the form
  1591 
  1592   P(t_case f1 ... fn x) =
  1593     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1594         ...
  1595        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1596      )
  1597   which can be added to a simpset via `addsplits'. The existing theorems
  1598   expand_list_case and expand_option_case have been renamed to
  1599   split_list_case and split_option_case.
  1600 
  1601 * HOL/Arithmetic:
  1602   - `pred n' is automatically converted to `n-1'.
  1603     Users are strongly encouraged not to use `pred' any longer,
  1604     because it will disappear altogether at some point.
  1605   - Users are strongly encouraged to write "0 < n" rather than
  1606     "n ~= 0". Theorems and proof tools have been modified towards this
  1607     `standard'.
  1608 
  1609 * HOL/Lists:
  1610   the function "set_of_list" has been renamed "set" (and its theorems too);
  1611   the function "nth" now takes its arguments in the reverse order and
  1612   has acquired the infix notation "!" as in "xs!n".
  1613 
  1614 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1615 
  1616 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1617   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1618 
  1619 * HOL/record: extensible records with schematic structural subtyping
  1620 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1621 still lacks various theorems and concrete record syntax;
  1622 
  1623 
  1624 *** HOLCF ***
  1625 
  1626 * removed "axioms" and "generated by" sections;
  1627 
  1628 * replaced "ops" section by extended "consts" section, which is capable of
  1629   handling the continuous function space "->" directly;
  1630 
  1631 * domain package:
  1632   . proves theorems immediately and stores them in the theory,
  1633   . creates hierachical name space,
  1634   . now uses normal mixfix annotations (instead of cinfix...),
  1635   . minor changes to some names and values (for consistency),
  1636   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1637   . separator between mutual domain defs: changed "," to "and",
  1638   . improved handling of sort constraints;  now they have to
  1639     appear on the left-hand side of the equations only;
  1640 
  1641 * fixed LAM <x,y,zs>.b syntax;
  1642 
  1643 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1644 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1645 
  1646 
  1647 *** FOL and ZF ***
  1648 
  1649 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1650   with `addloop' of the simplifier to faciliate case splitting in premises.
  1651 
  1652 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1653 in HOL, they strip ALL and --> from proved theorems;
  1654 
  1655 
  1656 
  1657 New in Isabelle94-8 (May 1997)
  1658 ------------------------------
  1659 
  1660 *** General Changes ***
  1661 
  1662 * new utilities to build / run / maintain Isabelle etc. (in parts
  1663 still somewhat experimental); old Makefiles etc. still functional;
  1664 
  1665 * new 'Isabelle System Manual';
  1666 
  1667 * INSTALL text, together with ./configure and ./build scripts;
  1668 
  1669 * reimplemented type inference for greater efficiency, better error
  1670 messages and clean internal interface;
  1671 
  1672 * prlim command for dealing with lots of subgoals (an easier way of
  1673 setting goals_limit);
  1674 
  1675 
  1676 *** Syntax ***
  1677 
  1678 * supports alternative (named) syntax tables (parser and pretty
  1679 printer); internal interface is provided by add_modesyntax(_i);
  1680 
  1681 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1682 be used in conjunction with the Isabelle symbol font; uses the
  1683 "symbols" syntax table;
  1684 
  1685 * added token_translation interface (may translate name tokens in
  1686 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1687 the current print_mode); IMPORTANT: user print translation functions
  1688 are responsible for marking newly introduced bounds
  1689 (Syntax.mark_boundT);
  1690 
  1691 * token translations for modes "xterm" and "xterm_color" that display
  1692 names in bold, underline etc. or colors (which requires a color
  1693 version of xterm);
  1694 
  1695 * infixes may now be declared with names independent of their syntax;
  1696 
  1697 * added typed_print_translation (like print_translation, but may
  1698 access type of constant);
  1699 
  1700 
  1701 *** Classical Reasoner ***
  1702 
  1703 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1704 some limitations.  Blast_tac...
  1705   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1706   + ignores elimination rules that don't have the correct format
  1707         (the conclusion MUST be a formula variable)
  1708   + ignores types, which can make HOL proofs fail
  1709   + rules must not require higher-order unification, e.g. apply_type in ZF
  1710     [message "Function Var's argument not a bound variable" relates to this]
  1711   + its proof strategy is more general but can actually be slower
  1712 
  1713 * substitution with equality assumptions no longer permutes other
  1714 assumptions;
  1715 
  1716 * minor changes in semantics of addafter (now called addaltern); renamed
  1717 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1718 (and access functions for it);
  1719 
  1720 * improved combination of classical reasoner and simplifier:
  1721   + functions for handling clasimpsets
  1722   + improvement of addss: now the simplifier is called _after_ the
  1723     safe steps.
  1724   + safe variant of addss called addSss: uses safe simplifications
  1725     _during_ the safe steps. It is more complete as it allows multiple
  1726     instantiations of unknowns (e.g. with slow_tac).
  1727 
  1728 *** Simplifier ***
  1729 
  1730 * added interface for simplification procedures (functions that
  1731 produce *proven* rewrite rules on the fly, depending on current
  1732 redex);
  1733 
  1734 * ordering on terms as parameter (used for ordered rewriting);
  1735 
  1736 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1737 
  1738 * the solver is now split into a safe and an unsafe part.
  1739 This should be invisible for the normal user, except that the
  1740 functions setsolver and addsolver have been renamed to setSolver and
  1741 addSolver; added safe_asm_full_simp_tac;
  1742 
  1743 
  1744 *** HOL ***
  1745 
  1746 * a generic induction tactic `induct_tac' which works for all datatypes and
  1747 also for type `nat';
  1748 
  1749 * a generic case distinction tactic `exhaust_tac' which works for all
  1750 datatypes and also for type `nat';
  1751 
  1752 * each datatype comes with a function `size';
  1753 
  1754 * patterns in case expressions allow tuple patterns as arguments to
  1755 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1756 
  1757 * primrec now also works with type nat;
  1758 
  1759 * recdef: a new declaration form, allows general recursive functions to be
  1760 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1761 
  1762 * the constant for negation has been renamed from "not" to "Not" to
  1763 harmonize with FOL, ZF, LK, etc.;
  1764 
  1765 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1766 infinite lists;
  1767 
  1768 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1769 
  1770 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1771 problems in commutative rings, using axiomatic type classes for + and *;
  1772 
  1773 * more examples in HOL/MiniML and HOL/Auth;
  1774 
  1775 * more default rewrite rules for quantifiers, union/intersection;
  1776 
  1777 * a new constant `arbitrary == @x.False';
  1778 
  1779 * HOLCF/IOA replaces old HOL/IOA;
  1780 
  1781 * HOLCF changes: derived all rules and arities
  1782   + axiomatic type classes instead of classes
  1783   + typedef instead of faking type definitions
  1784   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1785   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1786   + eliminated the types void, one, tr
  1787   + use unit lift and bool lift (with translations) instead of one and tr
  1788   + eliminated blift from Lift3.thy (use Def instead of blift)
  1789   all eliminated rules are derived as theorems --> no visible changes ;
  1790 
  1791 
  1792 *** ZF ***
  1793 
  1794 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1795 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1796 as ZF_cs addSIs [equalityI];
  1797 
  1798 
  1799 
  1800 New in Isabelle94-7 (November 96)
  1801 ---------------------------------
  1802 
  1803 * allowing negative levels (as offsets) in prlev and choplev;
  1804 
  1805 * super-linear speedup for large simplifications;
  1806 
  1807 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1808 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1809 FAIL); can suppress it using the command Delsimps (ex_simps @
  1810 all_simps); De Morgan laws are also now included, by default;
  1811 
  1812 * improved printing of ==>  :  ~:
  1813 
  1814 * new object-logic "Sequents" adds linear logic, while replacing LK
  1815 and Modal (thanks to Sara Kalvala);
  1816 
  1817 * HOL/Auth: correctness proofs for authentication protocols;
  1818 
  1819 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1820 examples on HOL/Auth);
  1821 
  1822 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1823 the rewriter and classical reasoner simultaneously;
  1824 
  1825 * function uresult no longer returns theorems in "standard" format;
  1826 regain previous version by: val uresult = standard o uresult;
  1827 
  1828 
  1829 
  1830 New in Isabelle94-6
  1831 -------------------
  1832 
  1833 * oracles -- these establish an interface between Isabelle and trusted
  1834 external reasoners, which may deliver results as theorems;
  1835 
  1836 * proof objects (in particular record all uses of oracles);
  1837 
  1838 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1839 
  1840 * "constdefs" section in theory files;
  1841 
  1842 * "primrec" section (HOL) no longer requires names;
  1843 
  1844 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1845 
  1846 
  1847 
  1848 New in Isabelle94-5
  1849 -------------------
  1850 
  1851 * reduced space requirements;
  1852 
  1853 * automatic HTML generation from theories;
  1854 
  1855 * theory files no longer require "..." (quotes) around most types;
  1856 
  1857 * new examples, including two proofs of the Church-Rosser theorem;
  1858 
  1859 * non-curried (1994) version of HOL is no longer distributed;
  1860 
  1861 
  1862 
  1863 New in Isabelle94-4
  1864 -------------------
  1865 
  1866 * greatly reduced space requirements;
  1867 
  1868 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1869 
  1870 * searchable theorem database (see the section "Retrieving theorems" on
  1871 page 8 of the Reference Manual);
  1872 
  1873 * new examples, including Grabczewski's monumental case study of the
  1874 Axiom of Choice;
  1875 
  1876 * The previous version of HOL renamed to Old_HOL;
  1877 
  1878 * The new version of HOL (previously called CHOL) uses a curried syntax
  1879 for functions.  Application looks like f a b instead of f(a,b);
  1880 
  1881 * Mutually recursive inductive definitions finally work in HOL;
  1882 
  1883 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1884 translates to the operator "split";
  1885 
  1886 
  1887 
  1888 New in Isabelle94-3
  1889 -------------------
  1890 
  1891 * new infix operator, addss, allowing the classical reasoner to
  1892 perform simplification at each step of its search.  Example:
  1893         fast_tac (cs addss ss)
  1894 
  1895 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1896 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1897 look like (a,b) instead of <a,b>;
  1898 
  1899 * PLEASE NOTE: CHOL will eventually replace HOL!
  1900 
  1901 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1902 It translates to the operator "split".  A new theory of integers is available;
  1903 
  1904 * In ZF, integer numerals now denote two's-complement binary integers.
  1905 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1906 
  1907 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1908 of the Axiom of Choice;
  1909 
  1910 
  1911 
  1912 New in Isabelle94-2
  1913 -------------------
  1914 
  1915 * Significantly faster resolution;
  1916 
  1917 * the different sections in a .thy file can now be mixed and repeated
  1918 freely;
  1919 
  1920 * Database of theorems for FOL, HOL and ZF.  New
  1921 commands including qed, qed_goal and bind_thm store theorems in the database.
  1922 
  1923 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1924 a given theory (thms_of), or find out what theory a theorem was proved in
  1925 (theory_of_thm);
  1926 
  1927 * Bugs fixed in the inductive definition and datatype packages;
  1928 
  1929 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1930 and HOL_dup_cs obsolete;
  1931 
  1932 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1933 have been removed;
  1934 
  1935 * Simpler definition of function space in ZF;
  1936 
  1937 * new results about cardinal and ordinal arithmetic in ZF;
  1938 
  1939 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1940 types;
  1941 
  1942 
  1943 $Id$