NEWS
author wenzelm
Tue Oct 16 17:51:12 2001 +0200 (2001-10-16)
changeset 11802 1d5f5d2427d2
parent 11797 1e29b79db3dc
child 11814 1de4a3321976
permissions -rw-r--r--
* HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
(beware of argument permutation!);
     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: 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 * Meta-level proof terms (by Stefan Berghofer), see also ref manual;
   125 
   126 * new token syntax "num" for plain numerals (without "#" of "xnum");
   127 potential INCOMPATIBILITY, since -0, -1 etc. are now separate tokens,
   128 so expressions involving minus need to be spaced properly;
   129 
   130 * Classical reasoner: renamed addaltern to addafter, addSaltern to
   131 addSafter;
   132 
   133 * syntax: support non-oriented infixes;
   134 
   135 * print modes "type_brackets" and "no_type_brackets" control output of
   136 nested => (types); the default behavior is "brackets";
   137 
   138 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   139 
   140 * system: Proof General keywords specification is now part of the
   141 Isabelle distribution (see etc/isar-keywords.el);
   142 
   143 * system: smart selection of Isabelle process versus Isabelle
   144 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   145 run both "isabelle" and "Isabelle" even if file names are badly
   146 damaged (executable inspects the case of the first letter of its own
   147 name); added separate "isabelle-process" and "isabelle-interface";
   148 
   149 
   150 
   151 New in Isabelle99-2 (February 2001)
   152 -----------------------------------
   153 
   154 *** Overview of INCOMPATIBILITIES ***
   155 
   156 * HOL: please note that theories in the Library and elsewhere often use the
   157 new-style (Isar) format; to refer to their theorems in an ML script you must
   158 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   159 
   160 * HOL: inductive package no longer splits induction rule aggressively,
   161 but only as far as specified by the introductions given; the old
   162 format may be recovered via ML function complete_split_rule or attribute
   163 'split_rule (complete)';
   164 
   165 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   166 gfp_Tarski to gfp_unfold;
   167 
   168 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   169 
   170 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   171 relation); infix "^^" has been renamed "``"; infix "``" has been
   172 renamed "`"; "univalent" has been renamed "single_valued";
   173 
   174 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   175 operation;
   176 
   177 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   178 
   179 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   180 
   181 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   182 consequence, it is no longer monotonic wrt. the local goal context
   183 (which is now passed through the inductive cases);
   184 
   185 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   186 \<gg> to \<ggreater>;
   187 
   188 
   189 *** Document preparation ***
   190 
   191 * \isabellestyle{NAME} selects version of Isabelle output (currently
   192 available: are "it" for near math-mode best-style output, "sl" for
   193 slanted text style, and "tt" for plain type-writer; if no
   194 \isabellestyle command is given, output is according to slanted
   195 type-writer);
   196 
   197 * support sub/super scripts (for single symbols only), input syntax is
   198 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   199 
   200 * some more standard symbols; see Appendix A of the system manual for
   201 the complete list of symbols defined in isabellesym.sty;
   202 
   203 * improved isabelle style files; more abstract symbol implementation
   204 (should now use \isamath{...} and \isatext{...} in custom symbol
   205 definitions);
   206 
   207 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   208 state; Note that presentation of goal states does not conform to
   209 actual human-readable proof documents.  Please do not include goal
   210 states into document output unless you really know what you are doing!
   211 
   212 * proper indentation of antiquoted output with proportional LaTeX
   213 fonts;
   214 
   215 * no_document ML operator temporarily disables LaTeX document
   216 generation;
   217 
   218 * isatool unsymbolize tunes sources for plain ASCII communication;
   219 
   220 
   221 *** Isar ***
   222 
   223 * Pure: Isar now suffers initial goal statements to contain unbound
   224 schematic variables (this does not conform to actual readable proof
   225 documents, due to unpredictable outcome and non-compositional proof
   226 checking); users who know what they are doing may use schematic goals
   227 for Prolog-style synthesis of proven results;
   228 
   229 * Pure: assumption method (an implicit finishing) now handles actual
   230 rules as well;
   231 
   232 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   233 initial goal, declare "that" only as Pure intro (only for single
   234 steps); the "that" rule assumption may now be involved in implicit
   235 finishing, thus ".." becomes a feasible for trivial obtains;
   236 
   237 * Pure: default proof step now includes 'intro_classes'; thus trivial
   238 instance proofs may be performed by "..";
   239 
   240 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   241 statements as well;
   242 
   243 * Pure: more robust selection of calculational rules;
   244 
   245 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   246 rule (as well as the assumption rule);
   247 
   248 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   249 lemmas, using the graph browser tool;
   250 
   251 * Pure: predict failure of "show" in interactive mode;
   252 
   253 * Pure: 'thms_containing' now takes actual terms as arguments;
   254 
   255 * HOL: improved method 'induct' --- now handles non-atomic goals
   256 (potential INCOMPATIBILITY); tuned error handling;
   257 
   258 * HOL: cases and induct rules now provide explicit hints about the
   259 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   260 any remaining facts are inserted into the goal verbatim;
   261 
   262 * HOL: local contexts (aka cases) may now contain term bindings as
   263 well; the 'cases' and 'induct' methods new provide a ?case binding for
   264 the result to be shown in each case;
   265 
   266 * HOL: added 'recdef_tc' command;
   267 
   268 * isatool convert assists in eliminating legacy ML scripts;
   269 
   270 
   271 *** HOL ***
   272 
   273 * HOL/Library: a collection of generic theories to be used together
   274 with main HOL; the theory loader path already includes this directory
   275 by default; the following existing theories have been moved here:
   276 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   277 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   278 
   279 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   280 modelling and verification task performed in Isabelle/HOL +
   281 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   282 
   283 * HOL/Algebra: special summation operator SUM no longer exists, it has
   284 been replaced by setsum; infix 'assoc' now has priority 50 (like
   285 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   286 'domain', this makes the theory consistent with mathematical
   287 literature;
   288 
   289 * HOL basics: added overloaded operations "inverse" and "divide"
   290 (infix "/"), syntax for generic "abs" operation, generic summation
   291 operator \<Sum>;
   292 
   293 * HOL/typedef: simplified package, provide more useful rules (see also
   294 HOL/subset.thy);
   295 
   296 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   297 now expressed as a proper nested rule (old-style tactic scripts may
   298 require atomize_strip_tac to cope with non-atomic premises);
   299 
   300 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   301 to "split_conv" (old name still available for compatibility);
   302 
   303 * HOL: improved concrete syntax for strings (e.g. allows translation
   304 rules with string literals);
   305 
   306 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   307 and Fleuriot's mechanization of analysis;
   308 
   309 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   310 
   311 
   312 *** CTT ***
   313 
   314 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   315 "lam" is displayed as TWO lambda-symbols
   316 
   317 * CTT: theory Main now available, containing everything (that is, Bool
   318 and Arith);
   319 
   320 
   321 *** General ***
   322 
   323 * Pure: the Simplifier has been implemented properly as a derived rule
   324 outside of the actual kernel (at last!); the overall performance
   325 penalty in practical applications is about 50%, while reliability of
   326 the Isabelle inference kernel has been greatly improved;
   327 
   328 * print modes "brackets" and "no_brackets" control output of nested =>
   329 (types) and ==> (props); the default behaviour is "brackets";
   330 
   331 * Provers: fast_tac (and friends) now handle actual object-logic rules
   332 as assumptions as well;
   333 
   334 * system: support Poly/ML 4.0;
   335 
   336 * system: isatool install handles KDE version 1 or 2;
   337 
   338 
   339 
   340 New in Isabelle99-1 (October 2000)
   341 ----------------------------------
   342 
   343 *** Overview of INCOMPATIBILITIES ***
   344 
   345 * HOL: simplification of natural numbers is much changed; to partly
   346 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   347 issue the following ML commands:
   348 
   349   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   350   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   351 
   352 * HOL: simplification no longer dives into case-expressions; this is
   353 controlled by "t.weak_case_cong" for each datatype t;
   354 
   355 * HOL: nat_less_induct renamed to less_induct;
   356 
   357 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   358 fixsome to patch .thy and .ML sources automatically;
   359 
   360   select_equality  -> some_equality
   361   select_eq_Ex     -> some_eq_ex
   362   selectI2EX       -> someI2_ex
   363   selectI2         -> someI2
   364   selectI          -> someI
   365   select1_equality -> some1_equality
   366   Eps_sym_eq       -> some_sym_eq_trivial
   367   Eps_eq           -> some_eq_trivial
   368 
   369 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   370 
   371 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   372 instead);
   373 
   374 * HOL: the recursion equations generated by 'recdef' are now called
   375 f.simps instead of f.rules;
   376 
   377 * HOL: qed_spec_mp now also handles bounded ALL as well;
   378 
   379 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   380 sometimes be needed;
   381 
   382 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   383 
   384 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   385 
   386 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   387 product is now "<*>" instead of "Times"; the lexicographic product is
   388 now "<*lex*>" instead of "**";
   389 
   390 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   391 of main HOL, but was unused); better use HOL's datatype package;
   392 
   393 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   394 the old syntax may be recovered as follows:
   395 
   396   syntax (symbols)
   397     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   398       (infixl "\\<oplus>" 100)
   399 
   400 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   401 
   402 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   403 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   404 internally;
   405 
   406 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   407 changed from A/r to A//r;
   408 
   409 * ZF: new treatment of arithmetic (nat & int) may break some old
   410 proofs;
   411 
   412 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   413 rulify -> rule_format, elimify -> elim_format, ...);
   414 
   415 * Isar/Provers: intro/elim/dest attributes changed; renamed
   416 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   417 should have to change intro!! to intro? only); replaced "delrule" by
   418 "rule del";
   419 
   420 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   421 
   422 * Provers: strengthened force_tac by using new first_best_tac;
   423 
   424 * LaTeX document preparation: several changes of isabelle.sty (see
   425 lib/texinputs);
   426 
   427 
   428 *** Document preparation ***
   429 
   430 * formal comments (text blocks etc.) in new-style theories may now
   431 contain antiquotations of thm/prop/term/typ/text to be presented
   432 according to latex print mode; concrete syntax is like this:
   433 @{term[show_types] "f(x) = a + x"};
   434 
   435 * isatool mkdir provides easy setup of Isabelle session directories,
   436 including proper document sources;
   437 
   438 * generated LaTeX sources are now deleted after successful run
   439 (isatool document -c); may retain a copy somewhere else via -D option
   440 of isatool usedir;
   441 
   442 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   443 style files, achieving self-contained LaTeX sources and simplifying
   444 LaTeX debugging;
   445 
   446 * old-style theories now produce (crude) LaTeX output as well;
   447 
   448 * browser info session directories are now self-contained (may be put
   449 on WWW server seperately); improved graphs of nested sessions; removed
   450 graph for 'all sessions';
   451 
   452 * several improvements in isabelle style files; \isabellestyle{it}
   453 produces fake math mode output; \isamarkupheader is now \section by
   454 default; see lib/texinputs/isabelle.sty etc.;
   455 
   456 
   457 *** Isar ***
   458 
   459 * Isar/Pure: local results and corresponding term bindings are now
   460 subject to Hindley-Milner polymorphism (similar to ML); this
   461 accommodates incremental type-inference very nicely;
   462 
   463 * Isar/Pure: new derived language element 'obtain' supports
   464 generalized existence reasoning;
   465 
   466 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   467 support accumulation of results, without applying any rules yet;
   468 useful to collect intermediate results without explicit name
   469 references, and for use with transitivity rules with more than 2
   470 premises;
   471 
   472 * Isar/Pure: scalable support for case-analysis type proofs: new
   473 'case' language element refers to local contexts symbolically, as
   474 produced by certain proof methods; internally, case names are attached
   475 to theorems as "tags";
   476 
   477 * Isar/Pure: theory command 'hide' removes declarations from
   478 class/type/const name spaces;
   479 
   480 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   481 indicate potential overloading;
   482 
   483 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   484 
   485 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   486 "{a,b,c}" instead of {a,b,c};
   487 
   488 * Isar/Pure now provides its own version of intro/elim/dest
   489 attributes; useful for building new logics, but beware of confusion
   490 with the version in Provers/classical;
   491 
   492 * Isar/Pure: the local context of (non-atomic) goals is provided via
   493 case name 'antecedent';
   494 
   495 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   496 to the current context is now done automatically);
   497 
   498 * Isar/Pure: theory command 'method_setup' provides a simple interface
   499 for definining proof methods in ML;
   500 
   501 * Isar/Provers: intro/elim/dest attributes changed; renamed
   502 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   503 most cases, one should have to change intro!! to intro? only);
   504 replaced "delrule" by "rule del";
   505 
   506 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   507 'symmetric' attribute (the latter supercedes [RS sym]);
   508 
   509 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   510 method modifier); 'simp' method: 'only:' modifier removes loopers as
   511 well (including splits);
   512 
   513 * Isar/Provers: Simplifier and Classical methods now support all kind
   514 of modifiers used in the past, including 'cong', 'iff', etc.
   515 
   516 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   517 of Simplifier and Classical reasoner);
   518 
   519 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   520 now support named cases; major packages (inductive, datatype, primrec,
   521 recdef) support case names and properly name parameters;
   522 
   523 * Isar/HOL: new transitivity rules for substitution in inequalities --
   524 monotonicity conditions are extracted to be proven at end of
   525 calculations;
   526 
   527 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   528 method anyway;
   529 
   530 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   531 split_if split_if_asm; datatype package provides theorems foo.splits =
   532 foo.split foo.split_asm for each datatype;
   533 
   534 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   535 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   536 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   537 use "(cases (simplified))" method in proper proof texts);
   538 
   539 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   540 
   541 * Isar: names of theorems etc. may be natural numbers as well;
   542 
   543 * Isar: 'pr' command: optional arguments for goals_limit and
   544 ProofContext.prems_limit; no longer prints theory contexts, but only
   545 proof states;
   546 
   547 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   548 additional print modes to be specified; e.g. "pr(latex)" will print
   549 proof state according to the Isabelle LaTeX style;
   550 
   551 * Isar: improved support for emulating tactic scripts, including proof
   552 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   553 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   554 (for HOL datatypes);
   555 
   556 * Isar: simplified (more robust) goal selection of proof methods: 1st
   557 goal, all goals, or explicit goal specifier (tactic emulation); thus
   558 'proof method scripts' have to be in depth-first order;
   559 
   560 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   561 
   562 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   563 should instead use individual commands for printing items
   564 (print_commands, print_methods etc.);
   565 
   566 * Isar: added 'nothing' --- the empty list of theorems;
   567 
   568 
   569 *** HOL ***
   570 
   571 * HOL/MicroJava: formalization of a fragment of Java, together with a
   572 corresponding virtual machine and a specification of its bytecode
   573 verifier and a lightweight bytecode verifier, including proofs of
   574 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   575 Cornelia Pusch (see also the homepage of project Bali at
   576 http://isabelle.in.tum.de/Bali/);
   577 
   578 * HOL/Algebra: new theory of rings and univariate polynomials, by
   579 Clemens Ballarin;
   580 
   581 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   582 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   583 Rasmussen;
   584 
   585 * HOL/Lattice: fundamental concepts of lattice theory and order
   586 structures, including duals, properties of bounds versus algebraic
   587 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   588 Theorem for complete lattices etc.; may also serve as a demonstration
   589 for abstract algebraic reasoning using axiomatic type classes, and
   590 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   591 
   592 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   593 von Oheimb;
   594 
   595 * HOL/IMPP: extension of IMP with local variables and mutually
   596 recursive procedures, by David von Oheimb;
   597 
   598 * HOL/Lambda: converted into new-style theory and document;
   599 
   600 * HOL/ex/Multiquote: example of multiple nested quotations and
   601 anti-quotations -- basically a generalized version of de-Bruijn
   602 representation; very useful in avoiding lifting of operations;
   603 
   604 * HOL/record: added general record equality rule to simpset; fixed
   605 select-update simplification procedure to handle extended records as
   606 well; admit "r" as field name;
   607 
   608 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   609 other numeric types and also as the identity of groups, rings, etc.;
   610 
   611 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   612 Types nat and int belong to this axclass;
   613 
   614 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   615    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   616    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   617   two terms #m*u and #n*u are replaced by #(m+n)*u
   618     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   619   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   620     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   621 
   622 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   623 powerful prover for predicate logic but knows nothing of clasets; see
   624 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   625 
   626 * HOL: new version of "case_tac" subsumes both boolean case split and
   627 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   628 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   629 
   630 * HOL: simplification no longer dives into case-expressions: only the
   631 selector expression is simplified, but not the remaining arms; to
   632 enable full simplification of case-expressions for datatype t, you may
   633 remove t.weak_case_cong from the simpset, either globally (Delcongs
   634 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   635 
   636 * HOL/recdef: the recursion equations generated by 'recdef' for
   637 function 'f' are now called f.simps instead of f.rules; if all
   638 termination conditions are proved automatically, these simplification
   639 rules are added to the simpset, as in primrec; rules may be named
   640 individually as well, resulting in a separate list of theorems for
   641 each equation;
   642 
   643 * HOL/While is a new theory that provides a while-combinator. It
   644 permits the definition of tail-recursive functions without the
   645 provision of a termination measure. The latter is necessary once the
   646 invariant proof rule for while is applied.
   647 
   648 * HOL: new (overloaded) notation for the set of elements below/above
   649 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   650 
   651 * HOL: theorems impI, allI, ballI bound as "strip";
   652 
   653 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   654 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   655 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   656 
   657 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   658 
   659 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   660 main HOL, but was unused);
   661 
   662 * HOL: fewer consts declared as global (e.g. have to refer to
   663 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   664 
   665 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   666 in case of overlap with user translations (e.g. judgements over
   667 tuples); (note that the underlying logical represenation is still
   668 bogus);
   669 
   670 
   671 *** ZF ***
   672 
   673 * ZF: simplification automatically cancels common terms in arithmetic
   674 expressions over nat and int;
   675 
   676 * ZF: new treatment of nat to minimize type-checking: all operators
   677 coerce their operands to a natural number using the function natify,
   678 making the algebraic laws unconditional;
   679 
   680 * ZF: as above, for int: operators coerce their operands to an integer
   681 using the function intify;
   682 
   683 * ZF: the integer library now contains many of the usual laws for the
   684 orderings, including $<=, and monotonicity laws for $+ and $*;
   685 
   686 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   687 simplification;
   688 
   689 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   690 to the simplifier and classical reasoner simultaneously;
   691 
   692 
   693 *** General ***
   694 
   695 * Provers: blast_tac now handles actual object-logic rules as
   696 assumptions; note that auto_tac uses blast_tac internally as well;
   697 
   698 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   699 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   700 
   701 * Provers: delrules now handles destruct rules as well (no longer need
   702 explicit make_elim);
   703 
   704 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   705   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   706 use instead the strong form,
   707   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   708 in HOL, FOL and ZF the function cla_make_elim will create such rules
   709 from destruct-rules;
   710 
   711 * Provers: Simplifier.easy_setup provides a fast path to basic
   712 Simplifier setup for new object-logics;
   713 
   714 * Pure: AST translation rules no longer require constant head on LHS;
   715 
   716 * Pure: improved name spaces: ambiguous output is qualified; support
   717 for hiding of names;
   718 
   719 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   720 XSYMBOL_HOME; no longer need to do manual configuration in most
   721 situations;
   722 
   723 * system: compression of ML heaps images may now be controlled via -c
   724 option of isabelle and isatool usedir (currently only observed by
   725 Poly/ML);
   726 
   727 * system: isatool installfonts may handle X-Symbol fonts as well (very
   728 useful for remote X11);
   729 
   730 * system: provide TAGS file for Isabelle sources;
   731 
   732 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   733 order;
   734 
   735 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   736 timing flag supersedes proof_timing and Toplevel.trace;
   737 
   738 * ML: new combinators |>> and |>>> for incremental transformations
   739 with secondary results (e.g. certain theory extensions):
   740 
   741 * ML: PureThy.add_defs gets additional argument to indicate potential
   742 overloading (usually false);
   743 
   744 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   745 results;
   746 
   747 
   748 
   749 New in Isabelle99 (October 1999)
   750 --------------------------------
   751 
   752 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   753 
   754 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   755 are no longer simplified.  (This allows the simplifier to unfold recursive
   756 functional programs.)  To restore the old behaviour, declare
   757 
   758     Delcongs [if_weak_cong];
   759 
   760 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   761 complement;
   762 
   763 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   764 
   765 * HOL/datatype: mutual_induct_tac no longer exists --
   766   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   767 
   768 * HOL/typedef: fixed type inference for representing set; type
   769 arguments now have to occur explicitly on the rhs as type constraints;
   770 
   771 * ZF: The con_defs part of an inductive definition may no longer refer
   772 to constants declared in the same theory;
   773 
   774 * HOL, ZF: the function mk_cases, generated by the inductive
   775 definition package, has lost an argument.  To simplify its result, it
   776 uses the default simpset instead of a supplied list of theorems.
   777 
   778 * HOL/List: the constructors of type list are now Nil and Cons;
   779 
   780 * Simplifier: the type of the infix ML functions
   781         setSSolver addSSolver setSolver addSolver
   782 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   783 for packaging solvers. A solver is created via
   784         mk_solver: string -> (thm list -> int -> tactic) -> solver
   785 where the string argument is only a comment.
   786 
   787 
   788 *** Proof tools ***
   789 
   790 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   791 decision procedure for linear arithmetic. Currently it is used for
   792 types `nat', `int', and `real' in HOL (see below); it can, should and
   793 will be instantiated for other types and logics as well.
   794 
   795 * The simplifier now accepts rewrite rules with flexible heads, eg
   796      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   797   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   798   matching.
   799 
   800 
   801 *** General ***
   802 
   803 * New Isabelle/Isar subsystem provides an alternative to traditional
   804 tactical theorem proving; together with the ProofGeneral/isar user
   805 interface it offers an interactive environment for developing human
   806 readable proof documents (Isar == Intelligible semi-automated
   807 reasoning); for further information see isatool doc isar-ref,
   808 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   809 
   810 * improved and simplified presentation of theories: better HTML markup
   811 (including colors), graph views in several sizes; isatool usedir now
   812 provides a proper interface for user theories (via -P option); actual
   813 document preparation based on (PDF)LaTeX is available as well (for
   814 new-style theories only); see isatool doc system for more information;
   815 
   816 * native support for Proof General, both for classic Isabelle and
   817 Isabelle/Isar;
   818 
   819 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   820 using the graph browser tool;
   821 
   822 * Isabelle manuals now also available as PDF;
   823 
   824 * theory loader rewritten from scratch (may not be fully
   825 bug-compatible); old loadpath variable has been replaced by show_path,
   826 add_path, del_path, reset_path functions; new operations such as
   827 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   828 isatool doc ref);
   829 
   830 * improved isatool install: option -k creates KDE application icon,
   831 option -p DIR installs standalone binaries;
   832 
   833 * added ML_PLATFORM setting (useful for cross-platform installations);
   834 more robust handling of platform specific ML images for SML/NJ;
   835 
   836 * the settings environment is now statically scoped, i.e. it is never
   837 created again in sub-processes invoked from isabelle, isatool, or
   838 Isabelle;
   839 
   840 * path element specification '~~' refers to '$ISABELLE_HOME';
   841 
   842 * in locales, the "assumes" and "defines" parts may be omitted if
   843 empty;
   844 
   845 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   846 long arrows);
   847 
   848 * new print_mode "HTML";
   849 
   850 * new flag show_tags controls display of tags of theorems (which are
   851 basically just comments that may be attached by some tools);
   852 
   853 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   854 mode and goal output format:
   855 
   856 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   857 244c244
   858 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   859 ---
   860 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   861 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   862 181c181
   863 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   864 ---
   865 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   866 
   867 * function bind_thms stores lists of theorems (cf. bind_thm);
   868 
   869 * new shorthand tactics ftac, eatac, datac, fatac;
   870 
   871 * qed (and friends) now accept "" as result name; in that case the
   872 theorem is not stored, but proper checks and presentation of the
   873 result still apply;
   874 
   875 * theorem database now also indexes constants "Trueprop", "all",
   876 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   877 
   878 
   879 *** HOL ***
   880 
   881 ** HOL arithmetic **
   882 
   883 * There are now decision procedures for linear arithmetic over nat and
   884 int:
   885 
   886 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   887 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   888 are treated as atomic; subformulae not involving type `nat' or `int'
   889 are ignored; quantified subformulae are ignored unless they are
   890 positive universal or negative existential. The tactic has to be
   891 invoked by hand and can be a little bit slow. In particular, the
   892 running time is exponential in the number of occurrences of `min' and
   893 `max', and `-' on `nat'.
   894 
   895 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   896 (negated) (in)equalities among the premises and the conclusion into
   897 account (i.e. no compound formulae) and does not know about `min' and
   898 `max', and `-' on `nat'. It is fast and is used automatically by the
   899 simplifier.
   900 
   901 NB: At the moment, these decision procedures do not cope with mixed
   902 nat/int formulae where the two parts interact, such as `m < n ==>
   903 int(m) < int(n)'.
   904 
   905 * HOL/Numeral provides a generic theory of numerals (encoded
   906 efficiently as bit strings); setup for types nat/int/real is in place;
   907 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   908 int, existing theories and proof scripts may require a few additional
   909 type constraints;
   910 
   911 * integer division and remainder can now be performed on constant
   912 arguments;
   913 
   914 * many properties of integer multiplication, division and remainder
   915 are now available;
   916 
   917 * An interface to the Stanford Validity Checker (SVC) is available through the
   918 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   919 are proved automatically.  SVC must be installed separately, and its results
   920 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   921 invocation of the underlying oracle).  For SVC see
   922   http://verify.stanford.edu/SVC
   923 
   924 * IsaMakefile: the HOL-Real target now builds an actual image;
   925 
   926 
   927 ** HOL misc **
   928 
   929 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   930 (in Isabelle/Isar) -- by Gertrud Bauer;
   931 
   932 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   933 analysis for assembly languages with subtypes;
   934 
   935 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   936 -- avoids syntactic ambiguities and treats state, transition, and
   937 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   938 changed syntax and (many) tactics;
   939 
   940 * HOL/inductive: Now also handles more general introduction rules such
   941   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   942   theorems are now maintained within the theory (maintained via the
   943   "mono" attribute);
   944 
   945 * HOL/datatype: Now also handles arbitrarily branching datatypes
   946   (using function types) such as
   947 
   948   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   949 
   950 * HOL/record: record_simproc (part of the default simpset) takes care
   951 of selectors applied to updated records; record_split_tac is no longer
   952 part of the default claset; update_defs may now be removed from the
   953 simpset in many cases; COMPATIBILITY: old behavior achieved by
   954 
   955   claset_ref () := claset() addSWrapper record_split_wrapper;
   956   Delsimprocs [record_simproc]
   957 
   958 * HOL/typedef: fixed type inference for representing set; type
   959 arguments now have to occur explicitly on the rhs as type constraints;
   960 
   961 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   962 names rather than an ML expression;
   963 
   964 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   965 supplied later.  Program schemes can be defined, such as
   966     "While B C s = (if B s then While B C (C s) else s)"
   967 where the well-founded relation can be chosen after B and C have been given.
   968 
   969 * HOL/List: the constructors of type list are now Nil and Cons;
   970 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   971 course, ML tools referring to List.list.op # etc. have to be adapted;
   972 
   973 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   974 disabled by default; run isabelle with option -m HOL to get back to
   975 the original Gordon/HOL-style output;
   976 
   977 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   978 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   979 
   980 * HOL basic syntax simplified (more orthogonal): all variants of
   981 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   982 Eps operator is provided as well: "SOME x. P[x]";
   983 
   984 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   985 
   986 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   987 thus available for user theories;
   988 
   989 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   990 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   991 time;
   992 
   993 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   994 several times and then mp;
   995 
   996 
   997 *** LK ***
   998 
   999 * the notation <<...>> is now available as a notation for sequences of
  1000 formulas;
  1001 
  1002 * the simplifier is now installed
  1003 
  1004 * the axiom system has been generalized (thanks to Soren Heilmann)
  1005 
  1006 * the classical reasoner now has a default rule database
  1007 
  1008 
  1009 *** ZF ***
  1010 
  1011 * new primrec section allows primitive recursive functions to be given
  1012 directly (as in HOL) over datatypes and the natural numbers;
  1013 
  1014 * new tactics induct_tac and exhaust_tac for induction (or case
  1015 analysis) over datatypes and the natural numbers;
  1016 
  1017 * the datatype declaration of type T now defines the recursor T_rec;
  1018 
  1019 * simplification automatically does freeness reasoning for datatype
  1020 constructors;
  1021 
  1022 * automatic type-inference, with AddTCs command to insert new
  1023 type-checking rules;
  1024 
  1025 * datatype introduction rules are now added as Safe Introduction rules
  1026 to the claset;
  1027 
  1028 * the syntax "if P then x else y" is now available in addition to
  1029 if(P,x,y);
  1030 
  1031 
  1032 *** Internal programming interfaces ***
  1033 
  1034 * tuned simplifier trace output; new flag debug_simp;
  1035 
  1036 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1037 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1038 
  1039 * AxClass.axclass_tac lost the theory argument;
  1040 
  1041 * tuned current_goals_markers semantics: begin / end goal avoids
  1042 printing empty lines;
  1043 
  1044 * removed prs and prs_fn hook, which was broken because it did not
  1045 include \n in its semantics, forcing writeln to add one
  1046 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1047 string -> unit if you really want to output text without newline;
  1048 
  1049 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1050 plain output, interface builders may have to enable 'isabelle_font'
  1051 mode to get Isabelle font glyphs as before;
  1052 
  1053 * refined token_translation interface; INCOMPATIBILITY: output length
  1054 now of type real instead of int;
  1055 
  1056 * theory loader actions may be traced via new ThyInfo.add_hook
  1057 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1058 your own database of information attached to *whole* theories -- as
  1059 opposed to intra-theory data slots offered via TheoryDataFun;
  1060 
  1061 * proper handling of dangling sort hypotheses (at last!);
  1062 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1063 extra sort hypotheses that can be witnessed from the type signature;
  1064 the force_strip_shyps flag is gone, any remaining shyps are simply
  1065 left in the theorem (with a warning issued by strip_shyps_warning);
  1066 
  1067 
  1068 
  1069 New in Isabelle98-1 (October 1998)
  1070 ----------------------------------
  1071 
  1072 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1073 
  1074 * several changes of automated proof tools;
  1075 
  1076 * HOL: major changes to the inductive and datatype packages, including
  1077 some minor incompatibilities of theory syntax;
  1078 
  1079 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1080 called `inj_on';
  1081 
  1082 * HOL: removed duplicate thms in Arith:
  1083   less_imp_add_less  should be replaced by  trans_less_add1
  1084   le_imp_add_le      should be replaced by  trans_le_add1
  1085 
  1086 * HOL: unary minus is now overloaded (new type constraints may be
  1087 required);
  1088 
  1089 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1090 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1091 now taken as an integer constant.
  1092 
  1093 * Pure: ML function 'theory_of' renamed to 'theory';
  1094 
  1095 
  1096 *** Proof tools ***
  1097 
  1098 * Simplifier:
  1099   1. Asm_full_simp_tac is now more aggressive.
  1100      1. It will sometimes reorient premises if that increases their power to
  1101         simplify.
  1102      2. It does no longer proceed strictly from left to right but may also
  1103         rotate premises to achieve further simplification.
  1104      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1105      old Asm_full_simp_tac in that it does not rotate premises.
  1106   2. The simplifier now knows a little bit about nat-arithmetic.
  1107 
  1108 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1109 allows for selected deletion of wrappers, by introduction of names for
  1110 wrapper functionals.  This implies that addbefore, addSbefore,
  1111 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1112 and that adding two tactics with the same name overwrites the first
  1113 one (emitting a warning).
  1114   type wrapper = (int -> tactic) -> (int -> tactic)
  1115   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1116   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1117   delWrapper, delSWrapper: claset *  string            -> claset
  1118   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1119 
  1120 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1121 semantics; addbefore now affects only the unsafe part of step_tac
  1122 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1123 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1124 by Force_tac;
  1125 
  1126 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1127 compWrapper; added safe wrapper (and access functions for it);
  1128 
  1129 * HOL/split_all_tac is now much faster and fails if there is nothing
  1130 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1131 and the names of the automatically generated variables have changed.
  1132 split_all_tac has moved within claset() from unsafe wrappers to safe
  1133 wrappers, which means that !!-bound variables are split much more
  1134 aggressively, and safe_tac and clarify_tac now split such variables.
  1135 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1136 Note: the same holds for record_split_tac, which does the job of
  1137 split_all_tac for record fields.
  1138 
  1139 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1140 permanently to the default simpset using Addsplits just like
  1141 Addsimps. They can be removed via Delsplits just like
  1142 Delsimps. Lower-case versions are also available.
  1143 
  1144 * HOL/Simplifier: The rule split_if is now part of the default
  1145 simpset. This means that the simplifier will eliminate all occurrences
  1146 of if-then-else in the conclusion of a goal. To prevent this, you can
  1147 either remove split_if completely from the default simpset by
  1148 `Delsplits [split_if]' or remove it in a specific call of the
  1149 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1150 other case splitting rules to/from the default simpset: every datatype
  1151 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1152 t is the name of the datatype).
  1153 
  1154 * Classical reasoner / Simplifier combination: new force_tac (and
  1155 derivatives Force_tac, force) combines rewriting and classical
  1156 reasoning (and whatever other tools) similarly to auto_tac, but is
  1157 aimed to solve the given subgoal completely.
  1158 
  1159 
  1160 *** General ***
  1161 
  1162 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1163 and `goalw': the theory is no longer needed as an explicit argument -
  1164 the current theory context is used; assumptions are no longer returned
  1165 at the ML-level unless one of them starts with ==> or !!; it is
  1166 recommended to convert to these new commands using isatool fixgoal
  1167 (backup your sources first!);
  1168 
  1169 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1170 the current theory context, and 'theory' to lookup stored theories;
  1171 
  1172 * new theory section 'locale' for declaring constants, assumptions and
  1173 definitions that have local scope;
  1174 
  1175 * new theory section 'nonterminals' for purely syntactic types;
  1176 
  1177 * new theory section 'setup' for generic ML setup functions
  1178 (e.g. package initialization);
  1179 
  1180 * the distribution now includes Isabelle icons: see
  1181 lib/logo/isabelle-{small,tiny}.xpm;
  1182 
  1183 * isatool install - install binaries with absolute references to
  1184 ISABELLE_HOME/bin;
  1185 
  1186 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1187 
  1188 * print mode 'emacs' reserved for Isamode;
  1189 
  1190 * support multiple print (ast) translations per constant name;
  1191 
  1192 * theorems involving oracles are now printed with a suffixed [!];
  1193 
  1194 
  1195 *** HOL ***
  1196 
  1197 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1198 
  1199 * HOL/inductive package reorganized and improved: now supports mutual
  1200 definitions such as
  1201 
  1202   inductive EVEN ODD
  1203     intrs
  1204       null "0 : EVEN"
  1205       oddI "n : EVEN ==> Suc n : ODD"
  1206       evenI "n : ODD ==> Suc n : EVEN"
  1207 
  1208 new theorem list "elims" contains an elimination rule for each of the
  1209 recursive sets; inductive definitions now handle disjunctive premises
  1210 correctly (also ZF);
  1211 
  1212 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1213 "mutual_induct" no longer exists - the induction rule is always
  1214 contained in "induct";
  1215 
  1216 
  1217 * HOL/datatype package re-implemented and greatly improved: now
  1218 supports mutually recursive datatypes such as
  1219 
  1220   datatype
  1221     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1222             | SUM ('a aexp) ('a aexp)
  1223             | DIFF ('a aexp) ('a aexp)
  1224             | NUM 'a
  1225   and
  1226     'a bexp = LESS ('a aexp) ('a aexp)
  1227             | AND ('a bexp) ('a bexp)
  1228             | OR ('a bexp) ('a bexp)
  1229 
  1230 as well as indirectly recursive datatypes such as
  1231 
  1232   datatype
  1233     ('a, 'b) term = Var 'a
  1234                   | App 'b ((('a, 'b) term) list)
  1235 
  1236 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1237 induction on mutually / indirectly recursive datatypes.
  1238 
  1239 Primrec equations are now stored in theory and can be accessed via
  1240 <function_name>.simps.
  1241 
  1242 INCOMPATIBILITIES:
  1243 
  1244   - Theories using datatypes must now have theory Datatype as an
  1245     ancestor.
  1246   - The specific <typename>.induct_tac no longer exists - use the
  1247     generic induct_tac instead.
  1248   - natE has been renamed to nat.exhaust - use exhaust_tac
  1249     instead of res_inst_tac ... natE. Note that the variable
  1250     names in nat.exhaust differ from the names in natE, this
  1251     may cause some "fragile" proofs to fail.
  1252   - The theorems split_<typename>_case and split_<typename>_case_asm
  1253     have been renamed to <typename>.split and <typename>.split_asm.
  1254   - Since default sorts of type variables are now handled correctly,
  1255     some datatype definitions may have to be annotated with explicit
  1256     sort constraints.
  1257   - Primrec definitions no longer require function name and type
  1258     of recursive argument.
  1259 
  1260 Consider using isatool fixdatatype to adapt your theories and proof
  1261 scripts to the new package (backup your sources first!).
  1262 
  1263 
  1264 * HOL/record package: considerably improved implementation; now
  1265 includes concrete syntax for record types, terms, updates; theorems
  1266 for surjective pairing and splitting !!-bound record variables; proof
  1267 support is as follows:
  1268 
  1269   1) standard conversions (selectors or updates applied to record
  1270 constructor terms) are part of the standard simpset;
  1271 
  1272   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1273 made part of standard simpset and claset via addIffs;
  1274 
  1275   3) a tactic for record field splitting (record_split_tac) is part of
  1276 the standard claset (addSWrapper);
  1277 
  1278 To get a better idea about these rules you may retrieve them via
  1279 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1280 the name of your record type.
  1281 
  1282 The split tactic 3) conceptually simplifies by the following rule:
  1283 
  1284   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1285 
  1286 Thus any record variable that is bound by meta-all will automatically
  1287 blow up into some record constructor term, consequently the
  1288 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1289 solve record problems automatically.
  1290 
  1291 
  1292 * reorganized the main HOL image: HOL/Integ and String loaded by
  1293 default; theory Main includes everything;
  1294 
  1295 * automatic simplification of integer sums and comparisons, using cancellation;
  1296 
  1297 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1298 
  1299 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1300 
  1301 * many new identities for unions, intersections, set difference, etc.;
  1302 
  1303 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1304 called split_if, split_split, split_sum_case and split_nat_case (to go
  1305 with add/delsplits);
  1306 
  1307 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1308 (?x::unit) = (); this is made part of the default simpset, which COULD
  1309 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1310 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1311 unit_abs_eta_conv is added in order to counter the effect of
  1312 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1313 %u.f();
  1314 
  1315 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1316 makes more sense);
  1317 
  1318 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1319   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1320   disjointness reasoning but breaking a few old proofs.
  1321 
  1322 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1323 to 'converse' from 'inverse' (for compatibility with ZF and some
  1324 literature);
  1325 
  1326 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1327 the well-founded relation;
  1328 
  1329 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1330     Compl A.  The "Compl" syntax remains available as input syntax for this
  1331     release ONLY.
  1332 
  1333 * HOL/Update: new theory of function updates:
  1334     f(a:=b) == %x. if x=a then b else f x
  1335 may also be iterated as in f(a:=b,c:=d,...);
  1336 
  1337 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1338 
  1339 * HOL/List:
  1340   - new function list_update written xs[i:=v] that updates the i-th
  1341     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1342   - new function `upt' written [i..j(] which generates the list
  1343     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1344     bound write [i..j], which is a shorthand for [i..j+1(].
  1345   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1346 
  1347 * HOL/Arith:
  1348   - removed 'pred' (predecessor) function;
  1349   - generalized some theorems about n-1;
  1350   - many new laws about "div" and "mod";
  1351   - new laws about greatest common divisors (see theory ex/Primes);
  1352 
  1353 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1354 instead of "inverse";
  1355 
  1356 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1357   of the multiset ordering;
  1358 
  1359 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1360   (not included by default);
  1361 
  1362 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1363 
  1364 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1365   programs, i.e. different program variables may have different types.
  1366 
  1367 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1368   [previously, this check worked only if the rewrite rule was unconditional]
  1369   Now rew can involve either definitions or equalities (either == or =).
  1370 
  1371 
  1372 *** ZF ***
  1373 
  1374 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1375   only the theorems proved on ZF.ML;
  1376 
  1377 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1378   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1379   disjointness reasoning but breaking a few old proofs.
  1380 
  1381 * ZF/Update: new theory of function updates
  1382     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1383   may also be iterated as in f(a:=b,c:=d,...);
  1384 
  1385 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1386 
  1387 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1388   [previously, this check worked only if the rewrite rule was unconditional]
  1389   Now rew can involve either definitions or equalities (either == or =).
  1390 
  1391 * case_tac provided for compatibility with HOL
  1392     (like the old excluded_middle_tac, but with subgoals swapped)
  1393 
  1394 
  1395 *** Internal programming interfaces ***
  1396 
  1397 * Pure: several new basic modules made available for general use, see
  1398 also src/Pure/README;
  1399 
  1400 * improved the theory data mechanism to support encapsulation (data
  1401 kind name replaced by private Object.kind, acting as authorization
  1402 key); new type-safe user interface via functor TheoryDataFun; generic
  1403 print_data function becomes basically useless;
  1404 
  1405 * removed global_names compatibility flag -- all theory declarations
  1406 are qualified by default;
  1407 
  1408 * module Pure/Syntax now offers quote / antiquote translation
  1409 functions (useful for Hoare logic etc. with implicit dependencies);
  1410 see HOL/ex/Antiquote for an example use;
  1411 
  1412 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1413 cterm -> thm;
  1414 
  1415 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1416 subgoal;
  1417 
  1418 * Display.print_goals function moved to Locale.print_goals;
  1419 
  1420 * standard print function for goals supports current_goals_markers
  1421 variable for marking begin of proof, end of proof, start of goal; the
  1422 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1423 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1424 for example;
  1425 
  1426 
  1427 
  1428 New in Isabelle98 (January 1998)
  1429 --------------------------------
  1430 
  1431 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1432 
  1433 * changed lexical syntax of terms / types: dots made part of long
  1434 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1435 
  1436 * simpset (and claset) reference variable replaced by functions
  1437 simpset / simpset_ref;
  1438 
  1439 * no longer supports theory aliases (via merge) and non-trivial
  1440 implicit merge of thms' signatures;
  1441 
  1442 * most internal names of constants changed due to qualified names;
  1443 
  1444 * changed Pure/Sequence interface (see Pure/seq.ML);
  1445 
  1446 
  1447 *** General Changes ***
  1448 
  1449 * hierachically structured name spaces (for consts, types, axms, thms
  1450 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1451 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1452 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1453 long_names for fully qualified output names; NOTE: ML programs
  1454 (special tactics, packages etc.) referring to internal names may have
  1455 to be adapted to cope with fully qualified names; in case of severe
  1456 backward campatibility problems try setting 'global_names' at compile
  1457 time to have enrything declared within a flat name space; one may also
  1458 fine tune name declarations in theories via the 'global' and 'local'
  1459 section;
  1460 
  1461 * reimplemented the implicit simpset and claset using the new anytype
  1462 data filed in signatures; references simpset:simpset ref etc. are
  1463 replaced by functions simpset:unit->simpset and
  1464 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1465 to patch your ML files accordingly;
  1466 
  1467 * HTML output now includes theory graph data for display with Java
  1468 applet or isatool browser; data generated automatically via isatool
  1469 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1470 
  1471 * defs may now be conditional; improved rewrite_goals_tac to handle
  1472 conditional equations;
  1473 
  1474 * defs now admits additional type arguments, using TYPE('a) syntax;
  1475 
  1476 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1477 creates a new theory node; implicit merge of thms' signatures is
  1478 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1479 transfer:theory->thm->thm in (rare) cases;
  1480 
  1481 * improved handling of draft signatures / theories; draft thms (and
  1482 ctyps, cterms) are automatically promoted to real ones;
  1483 
  1484 * slightly changed interfaces for oracles: admit many per theory, named
  1485 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1486 
  1487 * print_goals: optional output of const types (set show_consts and
  1488 show_types);
  1489 
  1490 * improved output of warnings (###) and errors (***);
  1491 
  1492 * subgoal_tac displays a warning if the new subgoal has type variables;
  1493 
  1494 * removed old README and Makefiles;
  1495 
  1496 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1497 
  1498 * removed obsolete init_pps and init_database;
  1499 
  1500 * deleted the obsolete tactical STATE, which was declared by
  1501     fun STATE tacfun st = tacfun st st;
  1502 
  1503 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1504 (which abbreviates $HOME);
  1505 
  1506 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1507 use isatool fixseq to adapt your ML programs (this works for fully
  1508 qualified references to the Sequence structure only!);
  1509 
  1510 * use_thy no longer requires writable current directory; it always
  1511 reloads .ML *and* .thy file, if either one is out of date;
  1512 
  1513 
  1514 *** Classical Reasoner ***
  1515 
  1516 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1517 tactics that use classical reasoning to simplify a subgoal without
  1518 splitting it into several subgoals;
  1519 
  1520 * Safe_tac: like safe_tac but uses the default claset;
  1521 
  1522 
  1523 *** Simplifier ***
  1524 
  1525 * added simplification meta rules:
  1526     (asm_)(full_)simplify: simpset -> thm -> thm;
  1527 
  1528 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1529 logics (again);
  1530 
  1531 * added prems argument to simplification procedures;
  1532 
  1533 * HOL, FOL, ZF: added infix function `addsplits':
  1534   instead of `<simpset> setloop (split_tac <thms>)'
  1535   you can simply write `<simpset> addsplits <thms>'
  1536 
  1537 
  1538 *** Syntax ***
  1539 
  1540 * TYPE('a) syntax for type reflection terms;
  1541 
  1542 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1543 
  1544 * pretty printer: changed order of mixfix annotation preference (again!);
  1545 
  1546 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1547 
  1548 
  1549 *** HOL ***
  1550 
  1551 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1552   with `addloop' of the simplifier to faciliate case splitting in premises.
  1553 
  1554 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1555 
  1556 * HOL/Auth: new protocol proofs including some for the Internet
  1557   protocol TLS;
  1558 
  1559 * HOL/Map: new theory of `maps' a la VDM;
  1560 
  1561 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1562 cancelling out common nat summands from =, <, <= (in)equalities, or
  1563 differences; simplification procedures nat_cancel_factor for
  1564 cancelling common factor from =, <, <= (in)equalities over natural
  1565 sums; nat_cancel contains both kinds of procedures, it is installed by
  1566 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1567 
  1568 * HOL/simplifier: terms of the form
  1569   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1570   are rewritten to
  1571   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1572   and those of the form
  1573   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1574   are rewritten to
  1575   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1576 
  1577 * HOL/datatype
  1578   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1579 
  1580   P(t_case f1 ... fn x) =
  1581      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1582         ...
  1583        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1584      )
  1585 
  1586   and a theorem `split_t_case_asm' of the form
  1587 
  1588   P(t_case f1 ... fn x) =
  1589     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1590         ...
  1591        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1592      )
  1593   which can be added to a simpset via `addsplits'. The existing theorems
  1594   expand_list_case and expand_option_case have been renamed to
  1595   split_list_case and split_option_case.
  1596 
  1597 * HOL/Arithmetic:
  1598   - `pred n' is automatically converted to `n-1'.
  1599     Users are strongly encouraged not to use `pred' any longer,
  1600     because it will disappear altogether at some point.
  1601   - Users are strongly encouraged to write "0 < n" rather than
  1602     "n ~= 0". Theorems and proof tools have been modified towards this
  1603     `standard'.
  1604 
  1605 * HOL/Lists:
  1606   the function "set_of_list" has been renamed "set" (and its theorems too);
  1607   the function "nth" now takes its arguments in the reverse order and
  1608   has acquired the infix notation "!" as in "xs!n".
  1609 
  1610 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1611 
  1612 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1613   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1614 
  1615 * HOL/record: extensible records with schematic structural subtyping
  1616 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1617 still lacks various theorems and concrete record syntax;
  1618 
  1619 
  1620 *** HOLCF ***
  1621 
  1622 * removed "axioms" and "generated by" sections;
  1623 
  1624 * replaced "ops" section by extended "consts" section, which is capable of
  1625   handling the continuous function space "->" directly;
  1626 
  1627 * domain package:
  1628   . proves theorems immediately and stores them in the theory,
  1629   . creates hierachical name space,
  1630   . now uses normal mixfix annotations (instead of cinfix...),
  1631   . minor changes to some names and values (for consistency),
  1632   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1633   . separator between mutual domain defs: changed "," to "and",
  1634   . improved handling of sort constraints;  now they have to
  1635     appear on the left-hand side of the equations only;
  1636 
  1637 * fixed LAM <x,y,zs>.b syntax;
  1638 
  1639 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1640 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1641 
  1642 
  1643 *** FOL and ZF ***
  1644 
  1645 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1646   with `addloop' of the simplifier to faciliate case splitting in premises.
  1647 
  1648 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1649 in HOL, they strip ALL and --> from proved theorems;
  1650 
  1651 
  1652 
  1653 New in Isabelle94-8 (May 1997)
  1654 ------------------------------
  1655 
  1656 *** General Changes ***
  1657 
  1658 * new utilities to build / run / maintain Isabelle etc. (in parts
  1659 still somewhat experimental); old Makefiles etc. still functional;
  1660 
  1661 * new 'Isabelle System Manual';
  1662 
  1663 * INSTALL text, together with ./configure and ./build scripts;
  1664 
  1665 * reimplemented type inference for greater efficiency, better error
  1666 messages and clean internal interface;
  1667 
  1668 * prlim command for dealing with lots of subgoals (an easier way of
  1669 setting goals_limit);
  1670 
  1671 
  1672 *** Syntax ***
  1673 
  1674 * supports alternative (named) syntax tables (parser and pretty
  1675 printer); internal interface is provided by add_modesyntax(_i);
  1676 
  1677 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1678 be used in conjunction with the Isabelle symbol font; uses the
  1679 "symbols" syntax table;
  1680 
  1681 * added token_translation interface (may translate name tokens in
  1682 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1683 the current print_mode); IMPORTANT: user print translation functions
  1684 are responsible for marking newly introduced bounds
  1685 (Syntax.mark_boundT);
  1686 
  1687 * token translations for modes "xterm" and "xterm_color" that display
  1688 names in bold, underline etc. or colors (which requires a color
  1689 version of xterm);
  1690 
  1691 * infixes may now be declared with names independent of their syntax;
  1692 
  1693 * added typed_print_translation (like print_translation, but may
  1694 access type of constant);
  1695 
  1696 
  1697 *** Classical Reasoner ***
  1698 
  1699 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1700 some limitations.  Blast_tac...
  1701   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1702   + ignores elimination rules that don't have the correct format
  1703         (the conclusion MUST be a formula variable)
  1704   + ignores types, which can make HOL proofs fail
  1705   + rules must not require higher-order unification, e.g. apply_type in ZF
  1706     [message "Function Var's argument not a bound variable" relates to this]
  1707   + its proof strategy is more general but can actually be slower
  1708 
  1709 * substitution with equality assumptions no longer permutes other
  1710 assumptions;
  1711 
  1712 * minor changes in semantics of addafter (now called addaltern); renamed
  1713 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1714 (and access functions for it);
  1715 
  1716 * improved combination of classical reasoner and simplifier:
  1717   + functions for handling clasimpsets
  1718   + improvement of addss: now the simplifier is called _after_ the
  1719     safe steps.
  1720   + safe variant of addss called addSss: uses safe simplifications
  1721     _during_ the safe steps. It is more complete as it allows multiple
  1722     instantiations of unknowns (e.g. with slow_tac).
  1723 
  1724 *** Simplifier ***
  1725 
  1726 * added interface for simplification procedures (functions that
  1727 produce *proven* rewrite rules on the fly, depending on current
  1728 redex);
  1729 
  1730 * ordering on terms as parameter (used for ordered rewriting);
  1731 
  1732 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1733 
  1734 * the solver is now split into a safe and an unsafe part.
  1735 This should be invisible for the normal user, except that the
  1736 functions setsolver and addsolver have been renamed to setSolver and
  1737 addSolver; added safe_asm_full_simp_tac;
  1738 
  1739 
  1740 *** HOL ***
  1741 
  1742 * a generic induction tactic `induct_tac' which works for all datatypes and
  1743 also for type `nat';
  1744 
  1745 * a generic case distinction tactic `exhaust_tac' which works for all
  1746 datatypes and also for type `nat';
  1747 
  1748 * each datatype comes with a function `size';
  1749 
  1750 * patterns in case expressions allow tuple patterns as arguments to
  1751 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1752 
  1753 * primrec now also works with type nat;
  1754 
  1755 * recdef: a new declaration form, allows general recursive functions to be
  1756 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1757 
  1758 * the constant for negation has been renamed from "not" to "Not" to
  1759 harmonize with FOL, ZF, LK, etc.;
  1760 
  1761 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1762 infinite lists;
  1763 
  1764 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1765 
  1766 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1767 problems in commutative rings, using axiomatic type classes for + and *;
  1768 
  1769 * more examples in HOL/MiniML and HOL/Auth;
  1770 
  1771 * more default rewrite rules for quantifiers, union/intersection;
  1772 
  1773 * a new constant `arbitrary == @x.False';
  1774 
  1775 * HOLCF/IOA replaces old HOL/IOA;
  1776 
  1777 * HOLCF changes: derived all rules and arities
  1778   + axiomatic type classes instead of classes
  1779   + typedef instead of faking type definitions
  1780   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1781   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1782   + eliminated the types void, one, tr
  1783   + use unit lift and bool lift (with translations) instead of one and tr
  1784   + eliminated blift from Lift3.thy (use Def instead of blift)
  1785   all eliminated rules are derived as theorems --> no visible changes ;
  1786 
  1787 
  1788 *** ZF ***
  1789 
  1790 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1791 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1792 as ZF_cs addSIs [equalityI];
  1793 
  1794 
  1795 
  1796 New in Isabelle94-7 (November 96)
  1797 ---------------------------------
  1798 
  1799 * allowing negative levels (as offsets) in prlev and choplev;
  1800 
  1801 * super-linear speedup for large simplifications;
  1802 
  1803 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1804 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1805 FAIL); can suppress it using the command Delsimps (ex_simps @
  1806 all_simps); De Morgan laws are also now included, by default;
  1807 
  1808 * improved printing of ==>  :  ~:
  1809 
  1810 * new object-logic "Sequents" adds linear logic, while replacing LK
  1811 and Modal (thanks to Sara Kalvala);
  1812 
  1813 * HOL/Auth: correctness proofs for authentication protocols;
  1814 
  1815 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1816 examples on HOL/Auth);
  1817 
  1818 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1819 the rewriter and classical reasoner simultaneously;
  1820 
  1821 * function uresult no longer returns theorems in "standard" format;
  1822 regain previous version by: val uresult = standard o uresult;
  1823 
  1824 
  1825 
  1826 New in Isabelle94-6
  1827 -------------------
  1828 
  1829 * oracles -- these establish an interface between Isabelle and trusted
  1830 external reasoners, which may deliver results as theorems;
  1831 
  1832 * proof objects (in particular record all uses of oracles);
  1833 
  1834 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1835 
  1836 * "constdefs" section in theory files;
  1837 
  1838 * "primrec" section (HOL) no longer requires names;
  1839 
  1840 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1841 
  1842 
  1843 
  1844 New in Isabelle94-5
  1845 -------------------
  1846 
  1847 * reduced space requirements;
  1848 
  1849 * automatic HTML generation from theories;
  1850 
  1851 * theory files no longer require "..." (quotes) around most types;
  1852 
  1853 * new examples, including two proofs of the Church-Rosser theorem;
  1854 
  1855 * non-curried (1994) version of HOL is no longer distributed;
  1856 
  1857 
  1858 
  1859 New in Isabelle94-4
  1860 -------------------
  1861 
  1862 * greatly reduced space requirements;
  1863 
  1864 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1865 
  1866 * searchable theorem database (see the section "Retrieving theorems" on
  1867 page 8 of the Reference Manual);
  1868 
  1869 * new examples, including Grabczewski's monumental case study of the
  1870 Axiom of Choice;
  1871 
  1872 * The previous version of HOL renamed to Old_HOL;
  1873 
  1874 * The new version of HOL (previously called CHOL) uses a curried syntax
  1875 for functions.  Application looks like f a b instead of f(a,b);
  1876 
  1877 * Mutually recursive inductive definitions finally work in HOL;
  1878 
  1879 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1880 translates to the operator "split";
  1881 
  1882 
  1883 
  1884 New in Isabelle94-3
  1885 -------------------
  1886 
  1887 * new infix operator, addss, allowing the classical reasoner to
  1888 perform simplification at each step of its search.  Example:
  1889         fast_tac (cs addss ss)
  1890 
  1891 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1892 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1893 look like (a,b) instead of <a,b>;
  1894 
  1895 * PLEASE NOTE: CHOL will eventually replace HOL!
  1896 
  1897 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1898 It translates to the operator "split".  A new theory of integers is available;
  1899 
  1900 * In ZF, integer numerals now denote two's-complement binary integers.
  1901 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1902 
  1903 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1904 of the Axiom of Choice;
  1905 
  1906 
  1907 
  1908 New in Isabelle94-2
  1909 -------------------
  1910 
  1911 * Significantly faster resolution;
  1912 
  1913 * the different sections in a .thy file can now be mixed and repeated
  1914 freely;
  1915 
  1916 * Database of theorems for FOL, HOL and ZF.  New
  1917 commands including qed, qed_goal and bind_thm store theorems in the database.
  1918 
  1919 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1920 a given theory (thms_of), or find out what theory a theorem was proved in
  1921 (theory_of_thm);
  1922 
  1923 * Bugs fixed in the inductive definition and datatype packages;
  1924 
  1925 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1926 and HOL_dup_cs obsolete;
  1927 
  1928 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1929 have been removed;
  1930 
  1931 * Simpler definition of function space in ZF;
  1932 
  1933 * new results about cardinal and ordinal arithmetic in ZF;
  1934 
  1935 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1936 types;
  1937 
  1938 
  1939 $Id$