NEWS
author wenzelm
Wed Oct 24 17:37:58 2001 +0200 (2001-10-24)
changeset 11921 2a0e9622dc51
parent 11899 e543b0f01a58
child 11930 1accec985349
permissions -rw-r--r--
* clasimp: ``iff'' declarations now handle conditional rules as well;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2001 (?? 2001)
     6 -----------------------------
     7 
     8 *** Document preparation ***
     9 
    10 * greatly simplified document preparation setup, including more
    11 graceful interpretation of isatool usedir -i/-d/-D options, and more
    12 instructive isatool mkdir; users should basically be able to get
    13 started with "isatool mkdir Test && isatool make";
    14 
    15 * theory dependency graph may now be incorporated into documents;
    16 isatool usedir -g true will produce session_graph.eps/.pdf for use
    17 with \includegraphics of LaTeX;
    18 
    19 * proper spacing of consecutive markup elements, especially text
    20 blocks after section headings;
    21 
    22 * support bold style (for single symbols only), input syntax is like
    23 this: "\<^bold>\<alpha>" or "\<^bold>A";
    24 
    25 * \<bullet> is now output as bold \cdot by default, which looks much
    26 better in printed text;
    27 
    28 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    29 note that these symbols are currently unavailable in Proof General /
    30 X-Symbol;
    31 
    32 
    33 *** Isar ***
    34 
    35 * improved proof by cases and induction:
    36   - 'case' command admits impromptu naming of parameters (such as
    37     "case (Suc n)");
    38   - 'induct' method divinates rule instantiation from the inductive
    39     claim; no longer requires excessive ?P bindings for proper
    40     instantiation of cases;
    41   - 'induct' method properly enumerates all possibilities of set/type
    42     rules; as a consequence facts may be also passed through *type*
    43     rules without further ado;
    44   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    45   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    46   - moved induct/cases attributes to Pure, methods to Provers;
    47   - generic method setup instantiated for FOL and HOL;
    48 
    49 * Pure: renamed "antecedent" case to "rule_context";
    50 
    51 * Pure: added 'corollary' command;
    52 
    53 * Pure: fixed 'token_translation' command;
    54 
    55 * Pure: removed obsolete 'exported' attribute;
    56 
    57 * Pure: dummy pattern "_" in is/let is now automatically ``lifted''
    58 over bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
    59 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
    60 
    61 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
    62 
    63 * HOL: 'recdef' now fails on unfinished automated proofs, use
    64 "(permissive)" option to recover old behavior;
    65 
    66 * HOL: 'inductive' now longer features separate (collective)
    67 attributes for 'intros';
    68 
    69 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
    70 
    71 
    72 *** HOL ***
    73 
    74 * HOL: moved over to sane numeral syntax; the new policy is as
    75 follows:
    76 
    77   - 0 and 1 are polymorphic constants, which are defined on any
    78   numeric type (nat, int, real etc.);
    79 
    80   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
    81   binary representation internally;
    82 
    83   - type nat has special constructor Suc, and generally prefers Suc 0
    84   over 1::nat and Suc (Suc 0) over 2::nat;
    85 
    86 This change may cause significant INCOMPATIBILITIES; here are some
    87 hints on converting existing sources:
    88 
    89   - due to the new "num" token, "-0" and "-1" etc. are now atomic
    90   entities, so expressions involving "-" (unary or binary minus) need
    91   to be spaced properly;
    92 
    93   - existing occurrences of "1" may need to be constraint "1::nat" or
    94   even replaced by Suc 0; similar for old "2";
    95 
    96   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
    97 
    98   - remove all special provisions on numerals in proofs;
    99 
   100 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   101 (beware of argument permutation!);
   102 
   103 * HOL: linorder_less_split superseded by linorder_cases;
   104 
   105 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   106 to peripheral theory "Hilbert_Choice";
   107 
   108 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   109 in this (rare) case use:
   110 
   111   delSWrapper "split_all_tac"
   112   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   113 
   114 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   115 MAY FAIL;
   116 
   117 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   118 Isabelle's type classes, ^ on functions and relations has too general
   119 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   120 necessary to attach explicit type constraints;
   121 
   122 * HOL: syntax translations now work properly with numerals and records
   123 expressions;
   124 
   125 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   126 Florian Kammüller;
   127 
   128 * HOL: eliminated global items
   129 
   130   const "()" -> "Product_Type.Unity"
   131   type "unit" -> "Product_Type.unit"
   132 
   133 
   134 *** ZF ***
   135 
   136 * ZF: the integer library now covers quotients and remainders, with
   137 many laws relating division to addition, multiplication, etc.;
   138 
   139 
   140 *** General ***
   141 
   142 * kernel: meta-level proof terms (by Stefan Berghofer), see also ref
   143 manual;
   144 
   145 * classical: renamed addaltern to addafter, addSaltern to addSafter;
   146 
   147 * clasimp: ``iff'' declarations now handle conditional rules as well;
   148 
   149 * syntax: new token syntax "num" for plain numerals (without "#" of
   150 "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now separate
   151 tokens, so expressions involving minus need to be spaced properly;
   152 
   153 * syntax: support non-oriented infixes;
   154 
   155 * syntax: print modes "type_brackets" and "no_type_brackets" control
   156 output of nested => (types); the default behavior is "type_brackets";
   157 
   158 * syntax: builtin parse translation for "_constify" turns valued
   159 tokens into AST constants;
   160 
   161 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   162 
   163 * system: Proof General keywords specification is now part of the
   164 Isabelle distribution (see etc/isar-keywords.el);
   165 
   166 * system: smart selection of Isabelle process versus Isabelle
   167 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   168 run both "isabelle" and "Isabelle" even if file names are badly
   169 damaged (executable inspects the case of the first letter of its own
   170 name); added separate "isabelle-process" and "isabelle-interface";
   171 
   172 
   173 
   174 New in Isabelle99-2 (February 2001)
   175 -----------------------------------
   176 
   177 *** Overview of INCOMPATIBILITIES ***
   178 
   179 * HOL: please note that theories in the Library and elsewhere often use the
   180 new-style (Isar) format; to refer to their theorems in an ML script you must
   181 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   182 
   183 * HOL: inductive package no longer splits induction rule aggressively,
   184 but only as far as specified by the introductions given; the old
   185 format may be recovered via ML function complete_split_rule or attribute
   186 'split_rule (complete)';
   187 
   188 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   189 gfp_Tarski to gfp_unfold;
   190 
   191 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   192 
   193 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   194 relation); infix "^^" has been renamed "``"; infix "``" has been
   195 renamed "`"; "univalent" has been renamed "single_valued";
   196 
   197 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   198 operation;
   199 
   200 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   201 
   202 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   203 
   204 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   205 consequence, it is no longer monotonic wrt. the local goal context
   206 (which is now passed through the inductive cases);
   207 
   208 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   209 \<gg> to \<ggreater>;
   210 
   211 
   212 *** Document preparation ***
   213 
   214 * \isabellestyle{NAME} selects version of Isabelle output (currently
   215 available: are "it" for near math-mode best-style output, "sl" for
   216 slanted text style, and "tt" for plain type-writer; if no
   217 \isabellestyle command is given, output is according to slanted
   218 type-writer);
   219 
   220 * support sub/super scripts (for single symbols only), input syntax is
   221 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   222 
   223 * some more standard symbols; see Appendix A of the system manual for
   224 the complete list of symbols defined in isabellesym.sty;
   225 
   226 * improved isabelle style files; more abstract symbol implementation
   227 (should now use \isamath{...} and \isatext{...} in custom symbol
   228 definitions);
   229 
   230 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   231 state; Note that presentation of goal states does not conform to
   232 actual human-readable proof documents.  Please do not include goal
   233 states into document output unless you really know what you are doing!
   234 
   235 * proper indentation of antiquoted output with proportional LaTeX
   236 fonts;
   237 
   238 * no_document ML operator temporarily disables LaTeX document
   239 generation;
   240 
   241 * isatool unsymbolize tunes sources for plain ASCII communication;
   242 
   243 
   244 *** Isar ***
   245 
   246 * Pure: Isar now suffers initial goal statements to contain unbound
   247 schematic variables (this does not conform to actual readable proof
   248 documents, due to unpredictable outcome and non-compositional proof
   249 checking); users who know what they are doing may use schematic goals
   250 for Prolog-style synthesis of proven results;
   251 
   252 * Pure: assumption method (an implicit finishing) now handles actual
   253 rules as well;
   254 
   255 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   256 initial goal, declare "that" only as Pure intro (only for single
   257 steps); the "that" rule assumption may now be involved in implicit
   258 finishing, thus ".." becomes a feasible for trivial obtains;
   259 
   260 * Pure: default proof step now includes 'intro_classes'; thus trivial
   261 instance proofs may be performed by "..";
   262 
   263 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   264 statements as well;
   265 
   266 * Pure: more robust selection of calculational rules;
   267 
   268 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   269 rule (as well as the assumption rule);
   270 
   271 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   272 lemmas, using the graph browser tool;
   273 
   274 * Pure: predict failure of "show" in interactive mode;
   275 
   276 * Pure: 'thms_containing' now takes actual terms as arguments;
   277 
   278 * HOL: improved method 'induct' --- now handles non-atomic goals
   279 (potential INCOMPATIBILITY); tuned error handling;
   280 
   281 * HOL: cases and induct rules now provide explicit hints about the
   282 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   283 any remaining facts are inserted into the goal verbatim;
   284 
   285 * HOL: local contexts (aka cases) may now contain term bindings as
   286 well; the 'cases' and 'induct' methods new provide a ?case binding for
   287 the result to be shown in each case;
   288 
   289 * HOL: added 'recdef_tc' command;
   290 
   291 * isatool convert assists in eliminating legacy ML scripts;
   292 
   293 
   294 *** HOL ***
   295 
   296 * HOL/Library: a collection of generic theories to be used together
   297 with main HOL; the theory loader path already includes this directory
   298 by default; the following existing theories have been moved here:
   299 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   300 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   301 
   302 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   303 modelling and verification task performed in Isabelle/HOL +
   304 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   305 
   306 * HOL/Algebra: special summation operator SUM no longer exists, it has
   307 been replaced by setsum; infix 'assoc' now has priority 50 (like
   308 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   309 'domain', this makes the theory consistent with mathematical
   310 literature;
   311 
   312 * HOL basics: added overloaded operations "inverse" and "divide"
   313 (infix "/"), syntax for generic "abs" operation, generic summation
   314 operator \<Sum>;
   315 
   316 * HOL/typedef: simplified package, provide more useful rules (see also
   317 HOL/subset.thy);
   318 
   319 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   320 now expressed as a proper nested rule (old-style tactic scripts may
   321 require atomize_strip_tac to cope with non-atomic premises);
   322 
   323 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   324 to "split_conv" (old name still available for compatibility);
   325 
   326 * HOL: improved concrete syntax for strings (e.g. allows translation
   327 rules with string literals);
   328 
   329 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   330 and Fleuriot's mechanization of analysis;
   331 
   332 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   333 
   334 
   335 *** CTT ***
   336 
   337 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   338 "lam" is displayed as TWO lambda-symbols
   339 
   340 * CTT: theory Main now available, containing everything (that is, Bool
   341 and Arith);
   342 
   343 
   344 *** General ***
   345 
   346 * Pure: the Simplifier has been implemented properly as a derived rule
   347 outside of the actual kernel (at last!); the overall performance
   348 penalty in practical applications is about 50%, while reliability of
   349 the Isabelle inference kernel has been greatly improved;
   350 
   351 * print modes "brackets" and "no_brackets" control output of nested =>
   352 (types) and ==> (props); the default behaviour is "brackets";
   353 
   354 * Provers: fast_tac (and friends) now handle actual object-logic rules
   355 as assumptions as well;
   356 
   357 * system: support Poly/ML 4.0;
   358 
   359 * system: isatool install handles KDE version 1 or 2;
   360 
   361 
   362 
   363 New in Isabelle99-1 (October 2000)
   364 ----------------------------------
   365 
   366 *** Overview of INCOMPATIBILITIES ***
   367 
   368 * HOL: simplification of natural numbers is much changed; to partly
   369 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   370 issue the following ML commands:
   371 
   372   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   373   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   374 
   375 * HOL: simplification no longer dives into case-expressions; this is
   376 controlled by "t.weak_case_cong" for each datatype t;
   377 
   378 * HOL: nat_less_induct renamed to less_induct;
   379 
   380 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   381 fixsome to patch .thy and .ML sources automatically;
   382 
   383   select_equality  -> some_equality
   384   select_eq_Ex     -> some_eq_ex
   385   selectI2EX       -> someI2_ex
   386   selectI2         -> someI2
   387   selectI          -> someI
   388   select1_equality -> some1_equality
   389   Eps_sym_eq       -> some_sym_eq_trivial
   390   Eps_eq           -> some_eq_trivial
   391 
   392 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   393 
   394 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   395 instead);
   396 
   397 * HOL: the recursion equations generated by 'recdef' are now called
   398 f.simps instead of f.rules;
   399 
   400 * HOL: qed_spec_mp now also handles bounded ALL as well;
   401 
   402 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   403 sometimes be needed;
   404 
   405 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   406 
   407 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   408 
   409 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   410 product is now "<*>" instead of "Times"; the lexicographic product is
   411 now "<*lex*>" instead of "**";
   412 
   413 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   414 of main HOL, but was unused); better use HOL's datatype package;
   415 
   416 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   417 the old syntax may be recovered as follows:
   418 
   419   syntax (symbols)
   420     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   421       (infixl "\\<oplus>" 100)
   422 
   423 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   424 
   425 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   426 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   427 internally;
   428 
   429 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   430 changed from A/r to A//r;
   431 
   432 * ZF: new treatment of arithmetic (nat & int) may break some old
   433 proofs;
   434 
   435 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   436 rulify -> rule_format, elimify -> elim_format, ...);
   437 
   438 * Isar/Provers: intro/elim/dest attributes changed; renamed
   439 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   440 should have to change intro!! to intro? only); replaced "delrule" by
   441 "rule del";
   442 
   443 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   444 
   445 * Provers: strengthened force_tac by using new first_best_tac;
   446 
   447 * LaTeX document preparation: several changes of isabelle.sty (see
   448 lib/texinputs);
   449 
   450 
   451 *** Document preparation ***
   452 
   453 * formal comments (text blocks etc.) in new-style theories may now
   454 contain antiquotations of thm/prop/term/typ/text to be presented
   455 according to latex print mode; concrete syntax is like this:
   456 @{term[show_types] "f(x) = a + x"};
   457 
   458 * isatool mkdir provides easy setup of Isabelle session directories,
   459 including proper document sources;
   460 
   461 * generated LaTeX sources are now deleted after successful run
   462 (isatool document -c); may retain a copy somewhere else via -D option
   463 of isatool usedir;
   464 
   465 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   466 style files, achieving self-contained LaTeX sources and simplifying
   467 LaTeX debugging;
   468 
   469 * old-style theories now produce (crude) LaTeX output as well;
   470 
   471 * browser info session directories are now self-contained (may be put
   472 on WWW server seperately); improved graphs of nested sessions; removed
   473 graph for 'all sessions';
   474 
   475 * several improvements in isabelle style files; \isabellestyle{it}
   476 produces fake math mode output; \isamarkupheader is now \section by
   477 default; see lib/texinputs/isabelle.sty etc.;
   478 
   479 
   480 *** Isar ***
   481 
   482 * Isar/Pure: local results and corresponding term bindings are now
   483 subject to Hindley-Milner polymorphism (similar to ML); this
   484 accommodates incremental type-inference very nicely;
   485 
   486 * Isar/Pure: new derived language element 'obtain' supports
   487 generalized existence reasoning;
   488 
   489 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   490 support accumulation of results, without applying any rules yet;
   491 useful to collect intermediate results without explicit name
   492 references, and for use with transitivity rules with more than 2
   493 premises;
   494 
   495 * Isar/Pure: scalable support for case-analysis type proofs: new
   496 'case' language element refers to local contexts symbolically, as
   497 produced by certain proof methods; internally, case names are attached
   498 to theorems as "tags";
   499 
   500 * Isar/Pure: theory command 'hide' removes declarations from
   501 class/type/const name spaces;
   502 
   503 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   504 indicate potential overloading;
   505 
   506 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   507 
   508 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   509 "{a,b,c}" instead of {a,b,c};
   510 
   511 * Isar/Pure now provides its own version of intro/elim/dest
   512 attributes; useful for building new logics, but beware of confusion
   513 with the version in Provers/classical;
   514 
   515 * Isar/Pure: the local context of (non-atomic) goals is provided via
   516 case name 'antecedent';
   517 
   518 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   519 to the current context is now done automatically);
   520 
   521 * Isar/Pure: theory command 'method_setup' provides a simple interface
   522 for definining proof methods in ML;
   523 
   524 * Isar/Provers: intro/elim/dest attributes changed; renamed
   525 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   526 most cases, one should have to change intro!! to intro? only);
   527 replaced "delrule" by "rule del";
   528 
   529 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   530 'symmetric' attribute (the latter supercedes [RS sym]);
   531 
   532 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   533 method modifier); 'simp' method: 'only:' modifier removes loopers as
   534 well (including splits);
   535 
   536 * Isar/Provers: Simplifier and Classical methods now support all kind
   537 of modifiers used in the past, including 'cong', 'iff', etc.
   538 
   539 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   540 of Simplifier and Classical reasoner);
   541 
   542 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   543 now support named cases; major packages (inductive, datatype, primrec,
   544 recdef) support case names and properly name parameters;
   545 
   546 * Isar/HOL: new transitivity rules for substitution in inequalities --
   547 monotonicity conditions are extracted to be proven at end of
   548 calculations;
   549 
   550 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   551 method anyway;
   552 
   553 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   554 split_if split_if_asm; datatype package provides theorems foo.splits =
   555 foo.split foo.split_asm for each datatype;
   556 
   557 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   558 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   559 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   560 use "(cases (simplified))" method in proper proof texts);
   561 
   562 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   563 
   564 * Isar: names of theorems etc. may be natural numbers as well;
   565 
   566 * Isar: 'pr' command: optional arguments for goals_limit and
   567 ProofContext.prems_limit; no longer prints theory contexts, but only
   568 proof states;
   569 
   570 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   571 additional print modes to be specified; e.g. "pr(latex)" will print
   572 proof state according to the Isabelle LaTeX style;
   573 
   574 * Isar: improved support for emulating tactic scripts, including proof
   575 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   576 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   577 (for HOL datatypes);
   578 
   579 * Isar: simplified (more robust) goal selection of proof methods: 1st
   580 goal, all goals, or explicit goal specifier (tactic emulation); thus
   581 'proof method scripts' have to be in depth-first order;
   582 
   583 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   584 
   585 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   586 should instead use individual commands for printing items
   587 (print_commands, print_methods etc.);
   588 
   589 * Isar: added 'nothing' --- the empty list of theorems;
   590 
   591 
   592 *** HOL ***
   593 
   594 * HOL/MicroJava: formalization of a fragment of Java, together with a
   595 corresponding virtual machine and a specification of its bytecode
   596 verifier and a lightweight bytecode verifier, including proofs of
   597 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   598 Cornelia Pusch (see also the homepage of project Bali at
   599 http://isabelle.in.tum.de/Bali/);
   600 
   601 * HOL/Algebra: new theory of rings and univariate polynomials, by
   602 Clemens Ballarin;
   603 
   604 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   605 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   606 Rasmussen;
   607 
   608 * HOL/Lattice: fundamental concepts of lattice theory and order
   609 structures, including duals, properties of bounds versus algebraic
   610 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   611 Theorem for complete lattices etc.; may also serve as a demonstration
   612 for abstract algebraic reasoning using axiomatic type classes, and
   613 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   614 
   615 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   616 von Oheimb;
   617 
   618 * HOL/IMPP: extension of IMP with local variables and mutually
   619 recursive procedures, by David von Oheimb;
   620 
   621 * HOL/Lambda: converted into new-style theory and document;
   622 
   623 * HOL/ex/Multiquote: example of multiple nested quotations and
   624 anti-quotations -- basically a generalized version of de-Bruijn
   625 representation; very useful in avoiding lifting of operations;
   626 
   627 * HOL/record: added general record equality rule to simpset; fixed
   628 select-update simplification procedure to handle extended records as
   629 well; admit "r" as field name;
   630 
   631 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   632 other numeric types and also as the identity of groups, rings, etc.;
   633 
   634 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   635 Types nat and int belong to this axclass;
   636 
   637 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   638    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   639    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   640   two terms #m*u and #n*u are replaced by #(m+n)*u
   641     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   642   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   643     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   644 
   645 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   646 powerful prover for predicate logic but knows nothing of clasets; see
   647 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   648 
   649 * HOL: new version of "case_tac" subsumes both boolean case split and
   650 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   651 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   652 
   653 * HOL: simplification no longer dives into case-expressions: only the
   654 selector expression is simplified, but not the remaining arms; to
   655 enable full simplification of case-expressions for datatype t, you may
   656 remove t.weak_case_cong from the simpset, either globally (Delcongs
   657 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   658 
   659 * HOL/recdef: the recursion equations generated by 'recdef' for
   660 function 'f' are now called f.simps instead of f.rules; if all
   661 termination conditions are proved automatically, these simplification
   662 rules are added to the simpset, as in primrec; rules may be named
   663 individually as well, resulting in a separate list of theorems for
   664 each equation;
   665 
   666 * HOL/While is a new theory that provides a while-combinator. It
   667 permits the definition of tail-recursive functions without the
   668 provision of a termination measure. The latter is necessary once the
   669 invariant proof rule for while is applied.
   670 
   671 * HOL: new (overloaded) notation for the set of elements below/above
   672 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   673 
   674 * HOL: theorems impI, allI, ballI bound as "strip";
   675 
   676 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   677 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   678 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   679 
   680 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   681 
   682 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   683 main HOL, but was unused);
   684 
   685 * HOL: fewer consts declared as global (e.g. have to refer to
   686 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   687 
   688 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   689 in case of overlap with user translations (e.g. judgements over
   690 tuples); (note that the underlying logical represenation is still
   691 bogus);
   692 
   693 
   694 *** ZF ***
   695 
   696 * ZF: simplification automatically cancels common terms in arithmetic
   697 expressions over nat and int;
   698 
   699 * ZF: new treatment of nat to minimize type-checking: all operators
   700 coerce their operands to a natural number using the function natify,
   701 making the algebraic laws unconditional;
   702 
   703 * ZF: as above, for int: operators coerce their operands to an integer
   704 using the function intify;
   705 
   706 * ZF: the integer library now contains many of the usual laws for the
   707 orderings, including $<=, and monotonicity laws for $+ and $*;
   708 
   709 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   710 simplification;
   711 
   712 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   713 to the simplifier and classical reasoner simultaneously;
   714 
   715 
   716 *** General ***
   717 
   718 * Provers: blast_tac now handles actual object-logic rules as
   719 assumptions; note that auto_tac uses blast_tac internally as well;
   720 
   721 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   722 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   723 
   724 * Provers: delrules now handles destruct rules as well (no longer need
   725 explicit make_elim);
   726 
   727 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   728   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   729 use instead the strong form,
   730   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   731 in HOL, FOL and ZF the function cla_make_elim will create such rules
   732 from destruct-rules;
   733 
   734 * Provers: Simplifier.easy_setup provides a fast path to basic
   735 Simplifier setup for new object-logics;
   736 
   737 * Pure: AST translation rules no longer require constant head on LHS;
   738 
   739 * Pure: improved name spaces: ambiguous output is qualified; support
   740 for hiding of names;
   741 
   742 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   743 XSYMBOL_HOME; no longer need to do manual configuration in most
   744 situations;
   745 
   746 * system: compression of ML heaps images may now be controlled via -c
   747 option of isabelle and isatool usedir (currently only observed by
   748 Poly/ML);
   749 
   750 * system: isatool installfonts may handle X-Symbol fonts as well (very
   751 useful for remote X11);
   752 
   753 * system: provide TAGS file for Isabelle sources;
   754 
   755 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   756 order;
   757 
   758 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   759 timing flag supersedes proof_timing and Toplevel.trace;
   760 
   761 * ML: new combinators |>> and |>>> for incremental transformations
   762 with secondary results (e.g. certain theory extensions):
   763 
   764 * ML: PureThy.add_defs gets additional argument to indicate potential
   765 overloading (usually false);
   766 
   767 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   768 results;
   769 
   770 
   771 
   772 New in Isabelle99 (October 1999)
   773 --------------------------------
   774 
   775 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   776 
   777 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   778 are no longer simplified.  (This allows the simplifier to unfold recursive
   779 functional programs.)  To restore the old behaviour, declare
   780 
   781     Delcongs [if_weak_cong];
   782 
   783 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   784 complement;
   785 
   786 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   787 
   788 * HOL/datatype: mutual_induct_tac no longer exists --
   789   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   790 
   791 * HOL/typedef: fixed type inference for representing set; type
   792 arguments now have to occur explicitly on the rhs as type constraints;
   793 
   794 * ZF: The con_defs part of an inductive definition may no longer refer
   795 to constants declared in the same theory;
   796 
   797 * HOL, ZF: the function mk_cases, generated by the inductive
   798 definition package, has lost an argument.  To simplify its result, it
   799 uses the default simpset instead of a supplied list of theorems.
   800 
   801 * HOL/List: the constructors of type list are now Nil and Cons;
   802 
   803 * Simplifier: the type of the infix ML functions
   804         setSSolver addSSolver setSolver addSolver
   805 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   806 for packaging solvers. A solver is created via
   807         mk_solver: string -> (thm list -> int -> tactic) -> solver
   808 where the string argument is only a comment.
   809 
   810 
   811 *** Proof tools ***
   812 
   813 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   814 decision procedure for linear arithmetic. Currently it is used for
   815 types `nat', `int', and `real' in HOL (see below); it can, should and
   816 will be instantiated for other types and logics as well.
   817 
   818 * The simplifier now accepts rewrite rules with flexible heads, eg
   819      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   820   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   821   matching.
   822 
   823 
   824 *** General ***
   825 
   826 * New Isabelle/Isar subsystem provides an alternative to traditional
   827 tactical theorem proving; together with the ProofGeneral/isar user
   828 interface it offers an interactive environment for developing human
   829 readable proof documents (Isar == Intelligible semi-automated
   830 reasoning); for further information see isatool doc isar-ref,
   831 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   832 
   833 * improved and simplified presentation of theories: better HTML markup
   834 (including colors), graph views in several sizes; isatool usedir now
   835 provides a proper interface for user theories (via -P option); actual
   836 document preparation based on (PDF)LaTeX is available as well (for
   837 new-style theories only); see isatool doc system for more information;
   838 
   839 * native support for Proof General, both for classic Isabelle and
   840 Isabelle/Isar;
   841 
   842 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   843 using the graph browser tool;
   844 
   845 * Isabelle manuals now also available as PDF;
   846 
   847 * theory loader rewritten from scratch (may not be fully
   848 bug-compatible); old loadpath variable has been replaced by show_path,
   849 add_path, del_path, reset_path functions; new operations such as
   850 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   851 isatool doc ref);
   852 
   853 * improved isatool install: option -k creates KDE application icon,
   854 option -p DIR installs standalone binaries;
   855 
   856 * added ML_PLATFORM setting (useful for cross-platform installations);
   857 more robust handling of platform specific ML images for SML/NJ;
   858 
   859 * the settings environment is now statically scoped, i.e. it is never
   860 created again in sub-processes invoked from isabelle, isatool, or
   861 Isabelle;
   862 
   863 * path element specification '~~' refers to '$ISABELLE_HOME';
   864 
   865 * in locales, the "assumes" and "defines" parts may be omitted if
   866 empty;
   867 
   868 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   869 long arrows);
   870 
   871 * new print_mode "HTML";
   872 
   873 * new flag show_tags controls display of tags of theorems (which are
   874 basically just comments that may be attached by some tools);
   875 
   876 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   877 mode and goal output format:
   878 
   879 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   880 244c244
   881 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   882 ---
   883 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   884 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   885 181c181
   886 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   887 ---
   888 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   889 
   890 * function bind_thms stores lists of theorems (cf. bind_thm);
   891 
   892 * new shorthand tactics ftac, eatac, datac, fatac;
   893 
   894 * qed (and friends) now accept "" as result name; in that case the
   895 theorem is not stored, but proper checks and presentation of the
   896 result still apply;
   897 
   898 * theorem database now also indexes constants "Trueprop", "all",
   899 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   900 
   901 
   902 *** HOL ***
   903 
   904 ** HOL arithmetic **
   905 
   906 * There are now decision procedures for linear arithmetic over nat and
   907 int:
   908 
   909 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   910 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   911 are treated as atomic; subformulae not involving type `nat' or `int'
   912 are ignored; quantified subformulae are ignored unless they are
   913 positive universal or negative existential. The tactic has to be
   914 invoked by hand and can be a little bit slow. In particular, the
   915 running time is exponential in the number of occurrences of `min' and
   916 `max', and `-' on `nat'.
   917 
   918 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   919 (negated) (in)equalities among the premises and the conclusion into
   920 account (i.e. no compound formulae) and does not know about `min' and
   921 `max', and `-' on `nat'. It is fast and is used automatically by the
   922 simplifier.
   923 
   924 NB: At the moment, these decision procedures do not cope with mixed
   925 nat/int formulae where the two parts interact, such as `m < n ==>
   926 int(m) < int(n)'.
   927 
   928 * HOL/Numeral provides a generic theory of numerals (encoded
   929 efficiently as bit strings); setup for types nat/int/real is in place;
   930 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   931 int, existing theories and proof scripts may require a few additional
   932 type constraints;
   933 
   934 * integer division and remainder can now be performed on constant
   935 arguments;
   936 
   937 * many properties of integer multiplication, division and remainder
   938 are now available;
   939 
   940 * An interface to the Stanford Validity Checker (SVC) is available through the
   941 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   942 are proved automatically.  SVC must be installed separately, and its results
   943 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   944 invocation of the underlying oracle).  For SVC see
   945   http://verify.stanford.edu/SVC
   946 
   947 * IsaMakefile: the HOL-Real target now builds an actual image;
   948 
   949 
   950 ** HOL misc **
   951 
   952 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   953 (in Isabelle/Isar) -- by Gertrud Bauer;
   954 
   955 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   956 analysis for assembly languages with subtypes;
   957 
   958 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   959 -- avoids syntactic ambiguities and treats state, transition, and
   960 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   961 changed syntax and (many) tactics;
   962 
   963 * HOL/inductive: Now also handles more general introduction rules such
   964   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   965   theorems are now maintained within the theory (maintained via the
   966   "mono" attribute);
   967 
   968 * HOL/datatype: Now also handles arbitrarily branching datatypes
   969   (using function types) such as
   970 
   971   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   972 
   973 * HOL/record: record_simproc (part of the default simpset) takes care
   974 of selectors applied to updated records; record_split_tac is no longer
   975 part of the default claset; update_defs may now be removed from the
   976 simpset in many cases; COMPATIBILITY: old behavior achieved by
   977 
   978   claset_ref () := claset() addSWrapper record_split_wrapper;
   979   Delsimprocs [record_simproc]
   980 
   981 * HOL/typedef: fixed type inference for representing set; type
   982 arguments now have to occur explicitly on the rhs as type constraints;
   983 
   984 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   985 names rather than an ML expression;
   986 
   987 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   988 supplied later.  Program schemes can be defined, such as
   989     "While B C s = (if B s then While B C (C s) else s)"
   990 where the well-founded relation can be chosen after B and C have been given.
   991 
   992 * HOL/List: the constructors of type list are now Nil and Cons;
   993 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   994 course, ML tools referring to List.list.op # etc. have to be adapted;
   995 
   996 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   997 disabled by default; run isabelle with option -m HOL to get back to
   998 the original Gordon/HOL-style output;
   999 
  1000 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1001 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1002 
  1003 * HOL basic syntax simplified (more orthogonal): all variants of
  1004 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1005 Eps operator is provided as well: "SOME x. P[x]";
  1006 
  1007 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1008 
  1009 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1010 thus available for user theories;
  1011 
  1012 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1013 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1014 time;
  1015 
  1016 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1017 several times and then mp;
  1018 
  1019 
  1020 *** LK ***
  1021 
  1022 * the notation <<...>> is now available as a notation for sequences of
  1023 formulas;
  1024 
  1025 * the simplifier is now installed
  1026 
  1027 * the axiom system has been generalized (thanks to Soren Heilmann)
  1028 
  1029 * the classical reasoner now has a default rule database
  1030 
  1031 
  1032 *** ZF ***
  1033 
  1034 * new primrec section allows primitive recursive functions to be given
  1035 directly (as in HOL) over datatypes and the natural numbers;
  1036 
  1037 * new tactics induct_tac and exhaust_tac for induction (or case
  1038 analysis) over datatypes and the natural numbers;
  1039 
  1040 * the datatype declaration of type T now defines the recursor T_rec;
  1041 
  1042 * simplification automatically does freeness reasoning for datatype
  1043 constructors;
  1044 
  1045 * automatic type-inference, with AddTCs command to insert new
  1046 type-checking rules;
  1047 
  1048 * datatype introduction rules are now added as Safe Introduction rules
  1049 to the claset;
  1050 
  1051 * the syntax "if P then x else y" is now available in addition to
  1052 if(P,x,y);
  1053 
  1054 
  1055 *** Internal programming interfaces ***
  1056 
  1057 * tuned simplifier trace output; new flag debug_simp;
  1058 
  1059 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1060 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1061 
  1062 * AxClass.axclass_tac lost the theory argument;
  1063 
  1064 * tuned current_goals_markers semantics: begin / end goal avoids
  1065 printing empty lines;
  1066 
  1067 * removed prs and prs_fn hook, which was broken because it did not
  1068 include \n in its semantics, forcing writeln to add one
  1069 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1070 string -> unit if you really want to output text without newline;
  1071 
  1072 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1073 plain output, interface builders may have to enable 'isabelle_font'
  1074 mode to get Isabelle font glyphs as before;
  1075 
  1076 * refined token_translation interface; INCOMPATIBILITY: output length
  1077 now of type real instead of int;
  1078 
  1079 * theory loader actions may be traced via new ThyInfo.add_hook
  1080 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1081 your own database of information attached to *whole* theories -- as
  1082 opposed to intra-theory data slots offered via TheoryDataFun;
  1083 
  1084 * proper handling of dangling sort hypotheses (at last!);
  1085 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1086 extra sort hypotheses that can be witnessed from the type signature;
  1087 the force_strip_shyps flag is gone, any remaining shyps are simply
  1088 left in the theorem (with a warning issued by strip_shyps_warning);
  1089 
  1090 
  1091 
  1092 New in Isabelle98-1 (October 1998)
  1093 ----------------------------------
  1094 
  1095 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1096 
  1097 * several changes of automated proof tools;
  1098 
  1099 * HOL: major changes to the inductive and datatype packages, including
  1100 some minor incompatibilities of theory syntax;
  1101 
  1102 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1103 called `inj_on';
  1104 
  1105 * HOL: removed duplicate thms in Arith:
  1106   less_imp_add_less  should be replaced by  trans_less_add1
  1107   le_imp_add_le      should be replaced by  trans_le_add1
  1108 
  1109 * HOL: unary minus is now overloaded (new type constraints may be
  1110 required);
  1111 
  1112 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1113 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1114 now taken as an integer constant.
  1115 
  1116 * Pure: ML function 'theory_of' renamed to 'theory';
  1117 
  1118 
  1119 *** Proof tools ***
  1120 
  1121 * Simplifier:
  1122   1. Asm_full_simp_tac is now more aggressive.
  1123      1. It will sometimes reorient premises if that increases their power to
  1124         simplify.
  1125      2. It does no longer proceed strictly from left to right but may also
  1126         rotate premises to achieve further simplification.
  1127      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1128      old Asm_full_simp_tac in that it does not rotate premises.
  1129   2. The simplifier now knows a little bit about nat-arithmetic.
  1130 
  1131 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1132 allows for selected deletion of wrappers, by introduction of names for
  1133 wrapper functionals.  This implies that addbefore, addSbefore,
  1134 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1135 and that adding two tactics with the same name overwrites the first
  1136 one (emitting a warning).
  1137   type wrapper = (int -> tactic) -> (int -> tactic)
  1138   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1139   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1140   delWrapper, delSWrapper: claset *  string            -> claset
  1141   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1142 
  1143 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1144 semantics; addbefore now affects only the unsafe part of step_tac
  1145 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1146 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1147 by Force_tac;
  1148 
  1149 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1150 compWrapper; added safe wrapper (and access functions for it);
  1151 
  1152 * HOL/split_all_tac is now much faster and fails if there is nothing
  1153 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1154 and the names of the automatically generated variables have changed.
  1155 split_all_tac has moved within claset() from unsafe wrappers to safe
  1156 wrappers, which means that !!-bound variables are split much more
  1157 aggressively, and safe_tac and clarify_tac now split such variables.
  1158 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1159 Note: the same holds for record_split_tac, which does the job of
  1160 split_all_tac for record fields.
  1161 
  1162 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1163 permanently to the default simpset using Addsplits just like
  1164 Addsimps. They can be removed via Delsplits just like
  1165 Delsimps. Lower-case versions are also available.
  1166 
  1167 * HOL/Simplifier: The rule split_if is now part of the default
  1168 simpset. This means that the simplifier will eliminate all occurrences
  1169 of if-then-else in the conclusion of a goal. To prevent this, you can
  1170 either remove split_if completely from the default simpset by
  1171 `Delsplits [split_if]' or remove it in a specific call of the
  1172 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1173 other case splitting rules to/from the default simpset: every datatype
  1174 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1175 t is the name of the datatype).
  1176 
  1177 * Classical reasoner / Simplifier combination: new force_tac (and
  1178 derivatives Force_tac, force) combines rewriting and classical
  1179 reasoning (and whatever other tools) similarly to auto_tac, but is
  1180 aimed to solve the given subgoal completely.
  1181 
  1182 
  1183 *** General ***
  1184 
  1185 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1186 and `goalw': the theory is no longer needed as an explicit argument -
  1187 the current theory context is used; assumptions are no longer returned
  1188 at the ML-level unless one of them starts with ==> or !!; it is
  1189 recommended to convert to these new commands using isatool fixgoal
  1190 (backup your sources first!);
  1191 
  1192 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1193 the current theory context, and 'theory' to lookup stored theories;
  1194 
  1195 * new theory section 'locale' for declaring constants, assumptions and
  1196 definitions that have local scope;
  1197 
  1198 * new theory section 'nonterminals' for purely syntactic types;
  1199 
  1200 * new theory section 'setup' for generic ML setup functions
  1201 (e.g. package initialization);
  1202 
  1203 * the distribution now includes Isabelle icons: see
  1204 lib/logo/isabelle-{small,tiny}.xpm;
  1205 
  1206 * isatool install - install binaries with absolute references to
  1207 ISABELLE_HOME/bin;
  1208 
  1209 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1210 
  1211 * print mode 'emacs' reserved for Isamode;
  1212 
  1213 * support multiple print (ast) translations per constant name;
  1214 
  1215 * theorems involving oracles are now printed with a suffixed [!];
  1216 
  1217 
  1218 *** HOL ***
  1219 
  1220 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1221 
  1222 * HOL/inductive package reorganized and improved: now supports mutual
  1223 definitions such as
  1224 
  1225   inductive EVEN ODD
  1226     intrs
  1227       null "0 : EVEN"
  1228       oddI "n : EVEN ==> Suc n : ODD"
  1229       evenI "n : ODD ==> Suc n : EVEN"
  1230 
  1231 new theorem list "elims" contains an elimination rule for each of the
  1232 recursive sets; inductive definitions now handle disjunctive premises
  1233 correctly (also ZF);
  1234 
  1235 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1236 "mutual_induct" no longer exists - the induction rule is always
  1237 contained in "induct";
  1238 
  1239 
  1240 * HOL/datatype package re-implemented and greatly improved: now
  1241 supports mutually recursive datatypes such as
  1242 
  1243   datatype
  1244     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1245             | SUM ('a aexp) ('a aexp)
  1246             | DIFF ('a aexp) ('a aexp)
  1247             | NUM 'a
  1248   and
  1249     'a bexp = LESS ('a aexp) ('a aexp)
  1250             | AND ('a bexp) ('a bexp)
  1251             | OR ('a bexp) ('a bexp)
  1252 
  1253 as well as indirectly recursive datatypes such as
  1254 
  1255   datatype
  1256     ('a, 'b) term = Var 'a
  1257                   | App 'b ((('a, 'b) term) list)
  1258 
  1259 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1260 induction on mutually / indirectly recursive datatypes.
  1261 
  1262 Primrec equations are now stored in theory and can be accessed via
  1263 <function_name>.simps.
  1264 
  1265 INCOMPATIBILITIES:
  1266 
  1267   - Theories using datatypes must now have theory Datatype as an
  1268     ancestor.
  1269   - The specific <typename>.induct_tac no longer exists - use the
  1270     generic induct_tac instead.
  1271   - natE has been renamed to nat.exhaust - use exhaust_tac
  1272     instead of res_inst_tac ... natE. Note that the variable
  1273     names in nat.exhaust differ from the names in natE, this
  1274     may cause some "fragile" proofs to fail.
  1275   - The theorems split_<typename>_case and split_<typename>_case_asm
  1276     have been renamed to <typename>.split and <typename>.split_asm.
  1277   - Since default sorts of type variables are now handled correctly,
  1278     some datatype definitions may have to be annotated with explicit
  1279     sort constraints.
  1280   - Primrec definitions no longer require function name and type
  1281     of recursive argument.
  1282 
  1283 Consider using isatool fixdatatype to adapt your theories and proof
  1284 scripts to the new package (backup your sources first!).
  1285 
  1286 
  1287 * HOL/record package: considerably improved implementation; now
  1288 includes concrete syntax for record types, terms, updates; theorems
  1289 for surjective pairing and splitting !!-bound record variables; proof
  1290 support is as follows:
  1291 
  1292   1) standard conversions (selectors or updates applied to record
  1293 constructor terms) are part of the standard simpset;
  1294 
  1295   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1296 made part of standard simpset and claset via addIffs;
  1297 
  1298   3) a tactic for record field splitting (record_split_tac) is part of
  1299 the standard claset (addSWrapper);
  1300 
  1301 To get a better idea about these rules you may retrieve them via
  1302 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1303 the name of your record type.
  1304 
  1305 The split tactic 3) conceptually simplifies by the following rule:
  1306 
  1307   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1308 
  1309 Thus any record variable that is bound by meta-all will automatically
  1310 blow up into some record constructor term, consequently the
  1311 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1312 solve record problems automatically.
  1313 
  1314 
  1315 * reorganized the main HOL image: HOL/Integ and String loaded by
  1316 default; theory Main includes everything;
  1317 
  1318 * automatic simplification of integer sums and comparisons, using cancellation;
  1319 
  1320 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1321 
  1322 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1323 
  1324 * many new identities for unions, intersections, set difference, etc.;
  1325 
  1326 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1327 called split_if, split_split, split_sum_case and split_nat_case (to go
  1328 with add/delsplits);
  1329 
  1330 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1331 (?x::unit) = (); this is made part of the default simpset, which COULD
  1332 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1333 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1334 unit_abs_eta_conv is added in order to counter the effect of
  1335 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1336 %u.f();
  1337 
  1338 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1339 makes more sense);
  1340 
  1341 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1342   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1343   disjointness reasoning but breaking a few old proofs.
  1344 
  1345 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1346 to 'converse' from 'inverse' (for compatibility with ZF and some
  1347 literature);
  1348 
  1349 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1350 the well-founded relation;
  1351 
  1352 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1353     Compl A.  The "Compl" syntax remains available as input syntax for this
  1354     release ONLY.
  1355 
  1356 * HOL/Update: new theory of function updates:
  1357     f(a:=b) == %x. if x=a then b else f x
  1358 may also be iterated as in f(a:=b,c:=d,...);
  1359 
  1360 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1361 
  1362 * HOL/List:
  1363   - new function list_update written xs[i:=v] that updates the i-th
  1364     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1365   - new function `upt' written [i..j(] which generates the list
  1366     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1367     bound write [i..j], which is a shorthand for [i..j+1(].
  1368   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1369 
  1370 * HOL/Arith:
  1371   - removed 'pred' (predecessor) function;
  1372   - generalized some theorems about n-1;
  1373   - many new laws about "div" and "mod";
  1374   - new laws about greatest common divisors (see theory ex/Primes);
  1375 
  1376 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1377 instead of "inverse";
  1378 
  1379 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1380   of the multiset ordering;
  1381 
  1382 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1383   (not included by default);
  1384 
  1385 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1386 
  1387 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1388   programs, i.e. different program variables may have different types.
  1389 
  1390 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1391   [previously, this check worked only if the rewrite rule was unconditional]
  1392   Now rew can involve either definitions or equalities (either == or =).
  1393 
  1394 
  1395 *** ZF ***
  1396 
  1397 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1398   only the theorems proved on ZF.ML;
  1399 
  1400 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1401   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1402   disjointness reasoning but breaking a few old proofs.
  1403 
  1404 * ZF/Update: new theory of function updates
  1405     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1406   may also be iterated as in f(a:=b,c:=d,...);
  1407 
  1408 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1409 
  1410 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1411   [previously, this check worked only if the rewrite rule was unconditional]
  1412   Now rew can involve either definitions or equalities (either == or =).
  1413 
  1414 * case_tac provided for compatibility with HOL
  1415     (like the old excluded_middle_tac, but with subgoals swapped)
  1416 
  1417 
  1418 *** Internal programming interfaces ***
  1419 
  1420 * Pure: several new basic modules made available for general use, see
  1421 also src/Pure/README;
  1422 
  1423 * improved the theory data mechanism to support encapsulation (data
  1424 kind name replaced by private Object.kind, acting as authorization
  1425 key); new type-safe user interface via functor TheoryDataFun; generic
  1426 print_data function becomes basically useless;
  1427 
  1428 * removed global_names compatibility flag -- all theory declarations
  1429 are qualified by default;
  1430 
  1431 * module Pure/Syntax now offers quote / antiquote translation
  1432 functions (useful for Hoare logic etc. with implicit dependencies);
  1433 see HOL/ex/Antiquote for an example use;
  1434 
  1435 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1436 cterm -> thm;
  1437 
  1438 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1439 subgoal;
  1440 
  1441 * Display.print_goals function moved to Locale.print_goals;
  1442 
  1443 * standard print function for goals supports current_goals_markers
  1444 variable for marking begin of proof, end of proof, start of goal; the
  1445 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1446 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1447 for example;
  1448 
  1449 
  1450 
  1451 New in Isabelle98 (January 1998)
  1452 --------------------------------
  1453 
  1454 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1455 
  1456 * changed lexical syntax of terms / types: dots made part of long
  1457 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1458 
  1459 * simpset (and claset) reference variable replaced by functions
  1460 simpset / simpset_ref;
  1461 
  1462 * no longer supports theory aliases (via merge) and non-trivial
  1463 implicit merge of thms' signatures;
  1464 
  1465 * most internal names of constants changed due to qualified names;
  1466 
  1467 * changed Pure/Sequence interface (see Pure/seq.ML);
  1468 
  1469 
  1470 *** General Changes ***
  1471 
  1472 * hierachically structured name spaces (for consts, types, axms, thms
  1473 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1474 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1475 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1476 long_names for fully qualified output names; NOTE: ML programs
  1477 (special tactics, packages etc.) referring to internal names may have
  1478 to be adapted to cope with fully qualified names; in case of severe
  1479 backward campatibility problems try setting 'global_names' at compile
  1480 time to have enrything declared within a flat name space; one may also
  1481 fine tune name declarations in theories via the 'global' and 'local'
  1482 section;
  1483 
  1484 * reimplemented the implicit simpset and claset using the new anytype
  1485 data filed in signatures; references simpset:simpset ref etc. are
  1486 replaced by functions simpset:unit->simpset and
  1487 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1488 to patch your ML files accordingly;
  1489 
  1490 * HTML output now includes theory graph data for display with Java
  1491 applet or isatool browser; data generated automatically via isatool
  1492 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1493 
  1494 * defs may now be conditional; improved rewrite_goals_tac to handle
  1495 conditional equations;
  1496 
  1497 * defs now admits additional type arguments, using TYPE('a) syntax;
  1498 
  1499 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1500 creates a new theory node; implicit merge of thms' signatures is
  1501 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1502 transfer:theory->thm->thm in (rare) cases;
  1503 
  1504 * improved handling of draft signatures / theories; draft thms (and
  1505 ctyps, cterms) are automatically promoted to real ones;
  1506 
  1507 * slightly changed interfaces for oracles: admit many per theory, named
  1508 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1509 
  1510 * print_goals: optional output of const types (set show_consts and
  1511 show_types);
  1512 
  1513 * improved output of warnings (###) and errors (***);
  1514 
  1515 * subgoal_tac displays a warning if the new subgoal has type variables;
  1516 
  1517 * removed old README and Makefiles;
  1518 
  1519 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1520 
  1521 * removed obsolete init_pps and init_database;
  1522 
  1523 * deleted the obsolete tactical STATE, which was declared by
  1524     fun STATE tacfun st = tacfun st st;
  1525 
  1526 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1527 (which abbreviates $HOME);
  1528 
  1529 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1530 use isatool fixseq to adapt your ML programs (this works for fully
  1531 qualified references to the Sequence structure only!);
  1532 
  1533 * use_thy no longer requires writable current directory; it always
  1534 reloads .ML *and* .thy file, if either one is out of date;
  1535 
  1536 
  1537 *** Classical Reasoner ***
  1538 
  1539 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1540 tactics that use classical reasoning to simplify a subgoal without
  1541 splitting it into several subgoals;
  1542 
  1543 * Safe_tac: like safe_tac but uses the default claset;
  1544 
  1545 
  1546 *** Simplifier ***
  1547 
  1548 * added simplification meta rules:
  1549     (asm_)(full_)simplify: simpset -> thm -> thm;
  1550 
  1551 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1552 logics (again);
  1553 
  1554 * added prems argument to simplification procedures;
  1555 
  1556 * HOL, FOL, ZF: added infix function `addsplits':
  1557   instead of `<simpset> setloop (split_tac <thms>)'
  1558   you can simply write `<simpset> addsplits <thms>'
  1559 
  1560 
  1561 *** Syntax ***
  1562 
  1563 * TYPE('a) syntax for type reflection terms;
  1564 
  1565 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1566 
  1567 * pretty printer: changed order of mixfix annotation preference (again!);
  1568 
  1569 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1570 
  1571 
  1572 *** HOL ***
  1573 
  1574 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1575   with `addloop' of the simplifier to faciliate case splitting in premises.
  1576 
  1577 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1578 
  1579 * HOL/Auth: new protocol proofs including some for the Internet
  1580   protocol TLS;
  1581 
  1582 * HOL/Map: new theory of `maps' a la VDM;
  1583 
  1584 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1585 cancelling out common nat summands from =, <, <= (in)equalities, or
  1586 differences; simplification procedures nat_cancel_factor for
  1587 cancelling common factor from =, <, <= (in)equalities over natural
  1588 sums; nat_cancel contains both kinds of procedures, it is installed by
  1589 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1590 
  1591 * HOL/simplifier: terms of the form
  1592   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1593   are rewritten to
  1594   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1595   and those of the form
  1596   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1597   are rewritten to
  1598   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1599 
  1600 * HOL/datatype
  1601   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1602 
  1603   P(t_case f1 ... fn x) =
  1604      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1605         ...
  1606        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1607      )
  1608 
  1609   and a theorem `split_t_case_asm' of the form
  1610 
  1611   P(t_case f1 ... fn x) =
  1612     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1613         ...
  1614        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1615      )
  1616   which can be added to a simpset via `addsplits'. The existing theorems
  1617   expand_list_case and expand_option_case have been renamed to
  1618   split_list_case and split_option_case.
  1619 
  1620 * HOL/Arithmetic:
  1621   - `pred n' is automatically converted to `n-1'.
  1622     Users are strongly encouraged not to use `pred' any longer,
  1623     because it will disappear altogether at some point.
  1624   - Users are strongly encouraged to write "0 < n" rather than
  1625     "n ~= 0". Theorems and proof tools have been modified towards this
  1626     `standard'.
  1627 
  1628 * HOL/Lists:
  1629   the function "set_of_list" has been renamed "set" (and its theorems too);
  1630   the function "nth" now takes its arguments in the reverse order and
  1631   has acquired the infix notation "!" as in "xs!n".
  1632 
  1633 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1634 
  1635 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1636   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1637 
  1638 * HOL/record: extensible records with schematic structural subtyping
  1639 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1640 still lacks various theorems and concrete record syntax;
  1641 
  1642 
  1643 *** HOLCF ***
  1644 
  1645 * removed "axioms" and "generated by" sections;
  1646 
  1647 * replaced "ops" section by extended "consts" section, which is capable of
  1648   handling the continuous function space "->" directly;
  1649 
  1650 * domain package:
  1651   . proves theorems immediately and stores them in the theory,
  1652   . creates hierachical name space,
  1653   . now uses normal mixfix annotations (instead of cinfix...),
  1654   . minor changes to some names and values (for consistency),
  1655   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1656   . separator between mutual domain defs: changed "," to "and",
  1657   . improved handling of sort constraints;  now they have to
  1658     appear on the left-hand side of the equations only;
  1659 
  1660 * fixed LAM <x,y,zs>.b syntax;
  1661 
  1662 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1663 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1664 
  1665 
  1666 *** FOL and ZF ***
  1667 
  1668 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1669   with `addloop' of the simplifier to faciliate case splitting in premises.
  1670 
  1671 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1672 in HOL, they strip ALL and --> from proved theorems;
  1673 
  1674 
  1675 
  1676 New in Isabelle94-8 (May 1997)
  1677 ------------------------------
  1678 
  1679 *** General Changes ***
  1680 
  1681 * new utilities to build / run / maintain Isabelle etc. (in parts
  1682 still somewhat experimental); old Makefiles etc. still functional;
  1683 
  1684 * new 'Isabelle System Manual';
  1685 
  1686 * INSTALL text, together with ./configure and ./build scripts;
  1687 
  1688 * reimplemented type inference for greater efficiency, better error
  1689 messages and clean internal interface;
  1690 
  1691 * prlim command for dealing with lots of subgoals (an easier way of
  1692 setting goals_limit);
  1693 
  1694 
  1695 *** Syntax ***
  1696 
  1697 * supports alternative (named) syntax tables (parser and pretty
  1698 printer); internal interface is provided by add_modesyntax(_i);
  1699 
  1700 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1701 be used in conjunction with the Isabelle symbol font; uses the
  1702 "symbols" syntax table;
  1703 
  1704 * added token_translation interface (may translate name tokens in
  1705 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1706 the current print_mode); IMPORTANT: user print translation functions
  1707 are responsible for marking newly introduced bounds
  1708 (Syntax.mark_boundT);
  1709 
  1710 * token translations for modes "xterm" and "xterm_color" that display
  1711 names in bold, underline etc. or colors (which requires a color
  1712 version of xterm);
  1713 
  1714 * infixes may now be declared with names independent of their syntax;
  1715 
  1716 * added typed_print_translation (like print_translation, but may
  1717 access type of constant);
  1718 
  1719 
  1720 *** Classical Reasoner ***
  1721 
  1722 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1723 some limitations.  Blast_tac...
  1724   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1725   + ignores elimination rules that don't have the correct format
  1726         (the conclusion MUST be a formula variable)
  1727   + ignores types, which can make HOL proofs fail
  1728   + rules must not require higher-order unification, e.g. apply_type in ZF
  1729     [message "Function Var's argument not a bound variable" relates to this]
  1730   + its proof strategy is more general but can actually be slower
  1731 
  1732 * substitution with equality assumptions no longer permutes other
  1733 assumptions;
  1734 
  1735 * minor changes in semantics of addafter (now called addaltern); renamed
  1736 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1737 (and access functions for it);
  1738 
  1739 * improved combination of classical reasoner and simplifier:
  1740   + functions for handling clasimpsets
  1741   + improvement of addss: now the simplifier is called _after_ the
  1742     safe steps.
  1743   + safe variant of addss called addSss: uses safe simplifications
  1744     _during_ the safe steps. It is more complete as it allows multiple
  1745     instantiations of unknowns (e.g. with slow_tac).
  1746 
  1747 *** Simplifier ***
  1748 
  1749 * added interface for simplification procedures (functions that
  1750 produce *proven* rewrite rules on the fly, depending on current
  1751 redex);
  1752 
  1753 * ordering on terms as parameter (used for ordered rewriting);
  1754 
  1755 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1756 
  1757 * the solver is now split into a safe and an unsafe part.
  1758 This should be invisible for the normal user, except that the
  1759 functions setsolver and addsolver have been renamed to setSolver and
  1760 addSolver; added safe_asm_full_simp_tac;
  1761 
  1762 
  1763 *** HOL ***
  1764 
  1765 * a generic induction tactic `induct_tac' which works for all datatypes and
  1766 also for type `nat';
  1767 
  1768 * a generic case distinction tactic `exhaust_tac' which works for all
  1769 datatypes and also for type `nat';
  1770 
  1771 * each datatype comes with a function `size';
  1772 
  1773 * patterns in case expressions allow tuple patterns as arguments to
  1774 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1775 
  1776 * primrec now also works with type nat;
  1777 
  1778 * recdef: a new declaration form, allows general recursive functions to be
  1779 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1780 
  1781 * the constant for negation has been renamed from "not" to "Not" to
  1782 harmonize with FOL, ZF, LK, etc.;
  1783 
  1784 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1785 infinite lists;
  1786 
  1787 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1788 
  1789 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1790 problems in commutative rings, using axiomatic type classes for + and *;
  1791 
  1792 * more examples in HOL/MiniML and HOL/Auth;
  1793 
  1794 * more default rewrite rules for quantifiers, union/intersection;
  1795 
  1796 * a new constant `arbitrary == @x.False';
  1797 
  1798 * HOLCF/IOA replaces old HOL/IOA;
  1799 
  1800 * HOLCF changes: derived all rules and arities
  1801   + axiomatic type classes instead of classes
  1802   + typedef instead of faking type definitions
  1803   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1804   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1805   + eliminated the types void, one, tr
  1806   + use unit lift and bool lift (with translations) instead of one and tr
  1807   + eliminated blift from Lift3.thy (use Def instead of blift)
  1808   all eliminated rules are derived as theorems --> no visible changes ;
  1809 
  1810 
  1811 *** ZF ***
  1812 
  1813 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1814 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1815 as ZF_cs addSIs [equalityI];
  1816 
  1817 
  1818 
  1819 New in Isabelle94-7 (November 96)
  1820 ---------------------------------
  1821 
  1822 * allowing negative levels (as offsets) in prlev and choplev;
  1823 
  1824 * super-linear speedup for large simplifications;
  1825 
  1826 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1827 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1828 FAIL); can suppress it using the command Delsimps (ex_simps @
  1829 all_simps); De Morgan laws are also now included, by default;
  1830 
  1831 * improved printing of ==>  :  ~:
  1832 
  1833 * new object-logic "Sequents" adds linear logic, while replacing LK
  1834 and Modal (thanks to Sara Kalvala);
  1835 
  1836 * HOL/Auth: correctness proofs for authentication protocols;
  1837 
  1838 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1839 examples on HOL/Auth);
  1840 
  1841 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1842 the rewriter and classical reasoner simultaneously;
  1843 
  1844 * function uresult no longer returns theorems in "standard" format;
  1845 regain previous version by: val uresult = standard o uresult;
  1846 
  1847 
  1848 
  1849 New in Isabelle94-6
  1850 -------------------
  1851 
  1852 * oracles -- these establish an interface between Isabelle and trusted
  1853 external reasoners, which may deliver results as theorems;
  1854 
  1855 * proof objects (in particular record all uses of oracles);
  1856 
  1857 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1858 
  1859 * "constdefs" section in theory files;
  1860 
  1861 * "primrec" section (HOL) no longer requires names;
  1862 
  1863 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1864 
  1865 
  1866 
  1867 New in Isabelle94-5
  1868 -------------------
  1869 
  1870 * reduced space requirements;
  1871 
  1872 * automatic HTML generation from theories;
  1873 
  1874 * theory files no longer require "..." (quotes) around most types;
  1875 
  1876 * new examples, including two proofs of the Church-Rosser theorem;
  1877 
  1878 * non-curried (1994) version of HOL is no longer distributed;
  1879 
  1880 
  1881 
  1882 New in Isabelle94-4
  1883 -------------------
  1884 
  1885 * greatly reduced space requirements;
  1886 
  1887 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1888 
  1889 * searchable theorem database (see the section "Retrieving theorems" on
  1890 page 8 of the Reference Manual);
  1891 
  1892 * new examples, including Grabczewski's monumental case study of the
  1893 Axiom of Choice;
  1894 
  1895 * The previous version of HOL renamed to Old_HOL;
  1896 
  1897 * The new version of HOL (previously called CHOL) uses a curried syntax
  1898 for functions.  Application looks like f a b instead of f(a,b);
  1899 
  1900 * Mutually recursive inductive definitions finally work in HOL;
  1901 
  1902 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1903 translates to the operator "split";
  1904 
  1905 
  1906 
  1907 New in Isabelle94-3
  1908 -------------------
  1909 
  1910 * new infix operator, addss, allowing the classical reasoner to
  1911 perform simplification at each step of its search.  Example:
  1912         fast_tac (cs addss ss)
  1913 
  1914 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1915 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1916 look like (a,b) instead of <a,b>;
  1917 
  1918 * PLEASE NOTE: CHOL will eventually replace HOL!
  1919 
  1920 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1921 It translates to the operator "split".  A new theory of integers is available;
  1922 
  1923 * In ZF, integer numerals now denote two's-complement binary integers.
  1924 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1925 
  1926 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1927 of the Axiom of Choice;
  1928 
  1929 
  1930 
  1931 New in Isabelle94-2
  1932 -------------------
  1933 
  1934 * Significantly faster resolution;
  1935 
  1936 * the different sections in a .thy file can now be mixed and repeated
  1937 freely;
  1938 
  1939 * Database of theorems for FOL, HOL and ZF.  New
  1940 commands including qed, qed_goal and bind_thm store theorems in the database.
  1941 
  1942 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1943 a given theory (thms_of), or find out what theory a theorem was proved in
  1944 (theory_of_thm);
  1945 
  1946 * Bugs fixed in the inductive definition and datatype packages;
  1947 
  1948 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1949 and HOL_dup_cs obsolete;
  1950 
  1951 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1952 have been removed;
  1953 
  1954 * Simpler definition of function space in ZF;
  1955 
  1956 * new results about cardinal and ordinal arithmetic in ZF;
  1957 
  1958 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1959 types;
  1960 
  1961 
  1962 $Id$