NEWS
author wenzelm
Thu Oct 25 22:42:12 2001 +0200 (2001-10-25)
changeset 11937 2a2b1182a23b
parent 11936 fef099613354
child 11952 b10f1e8862f4
permissions -rw-r--r--
* HOL/record:
- removed "more" class (simply use "term") -- INCOMPATIBILITY;
     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 over
    58 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 * Provers: 'simplified' attribute may refer to explicit rules instead
    62 of full simplifier context; 'iff' attribute handles conditional rules;
    63 
    64 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
    65 
    66 * HOL: 'recdef' now fails on unfinished automated proofs, use
    67 "(permissive)" option to recover old behavior;
    68 
    69 * HOL: 'inductive' no longer features separate (collective) attributes
    70 for 'intros' (was found too confusing);
    71 
    72 
    73 
    74 *** HOL ***
    75 
    76 * HOL: moved over to sane numeral syntax; the new policy is as
    77 follows:
    78 
    79   - 0 and 1 are polymorphic constants, which are defined on any
    80   numeric type (nat, int, real etc.);
    81 
    82   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
    83   binary representation internally;
    84 
    85   - type nat has special constructor Suc, and generally prefers Suc 0
    86   over 1::nat and Suc (Suc 0) over 2::nat;
    87 
    88 This change may cause significant INCOMPATIBILITIES; here are some
    89 hints on converting existing sources:
    90 
    91   - due to the new "num" token, "-0" and "-1" etc. are now atomic
    92   entities, so expressions involving "-" (unary or binary minus) need
    93   to be spaced properly;
    94 
    95   - existing occurrences of "1" may need to be constraint "1::nat" or
    96   even replaced by Suc 0; similar for old "2";
    97 
    98   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
    99 
   100   - remove all special provisions on numerals in proofs;
   101 
   102 * HOL/record:
   103   - removed old "make" and "make_scheme" operations -- INCOMPATIBILITY;
   104   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   105   - provides cases/induct rules for use with corresponding Isar methods;
   106   - new derived operations "make" (for adding fields of current
   107     record), "extend" to promote fixed record to record scheme, and
   108     "truncate" for the reverse; cf. theorems "derived_defs", which are
   109     *not* declared as simp by default;
   110   - internal definitions directly based on a light-weight abstract
   111     theory of product types over typedef rather than datatype;
   112 
   113 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   114 
   115 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   116 (beware of argument permutation!);
   117 
   118 * HOL: linorder_less_split superseded by linorder_cases;
   119 
   120 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   121 to peripheral theory "Hilbert_Choice";
   122 
   123 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   124 in this (rare) case use:
   125 
   126   delSWrapper "split_all_tac"
   127   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   128 
   129 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   130 MAY FAIL;
   131 
   132 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   133 Isabelle's type classes, ^ on functions and relations has too general
   134 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   135 necessary to attach explicit type constraints;
   136 
   137 * HOL: syntax translations now work properly with numerals and records
   138 expressions;
   139 
   140 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   141 Florian Kammüller;
   142 
   143 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   144 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   145 renamed "Product_Type.unit";
   146 
   147 
   148 *** ZF ***
   149 
   150 * ZF: the integer library now covers quotients and remainders, with
   151 many laws relating division to addition, multiplication, etc.;
   152 
   153 
   154 *** General ***
   155 
   156 * kernel: meta-level proof terms (by Stefan Berghofer), see also ref
   157 manual;
   158 
   159 * classical: renamed addaltern to addafter, addSaltern to addSafter;
   160 
   161 * clasimp: ``iff'' declarations now handle conditional rules as well;
   162 
   163 * syntax: new token syntax "num" for plain numerals (without "#" of
   164 "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now separate
   165 tokens, so expressions involving minus need to be spaced properly;
   166 
   167 * syntax: support non-oriented infixes;
   168 
   169 * syntax: print modes "type_brackets" and "no_type_brackets" control
   170 output of nested => (types); the default behavior is "type_brackets";
   171 
   172 * syntax: builtin parse translation for "_constify" turns valued
   173 tokens into AST constants;
   174 
   175 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   176 
   177 * system: Proof General keywords specification is now part of the
   178 Isabelle distribution (see etc/isar-keywords.el);
   179 
   180 * system: smart selection of Isabelle process versus Isabelle
   181 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   182 run both "isabelle" and "Isabelle" even if file names are badly
   183 damaged (executable inspects the case of the first letter of its own
   184 name); added separate "isabelle-process" and "isabelle-interface";
   185 
   186 
   187 
   188 New in Isabelle99-2 (February 2001)
   189 -----------------------------------
   190 
   191 *** Overview of INCOMPATIBILITIES ***
   192 
   193 * HOL: please note that theories in the Library and elsewhere often use the
   194 new-style (Isar) format; to refer to their theorems in an ML script you must
   195 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   196 
   197 * HOL: inductive package no longer splits induction rule aggressively,
   198 but only as far as specified by the introductions given; the old
   199 format may be recovered via ML function complete_split_rule or attribute
   200 'split_rule (complete)';
   201 
   202 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   203 gfp_Tarski to gfp_unfold;
   204 
   205 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   206 
   207 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   208 relation); infix "^^" has been renamed "``"; infix "``" has been
   209 renamed "`"; "univalent" has been renamed "single_valued";
   210 
   211 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   212 operation;
   213 
   214 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   215 
   216 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   217 
   218 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   219 consequence, it is no longer monotonic wrt. the local goal context
   220 (which is now passed through the inductive cases);
   221 
   222 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   223 \<gg> to \<ggreater>;
   224 
   225 
   226 *** Document preparation ***
   227 
   228 * \isabellestyle{NAME} selects version of Isabelle output (currently
   229 available: are "it" for near math-mode best-style output, "sl" for
   230 slanted text style, and "tt" for plain type-writer; if no
   231 \isabellestyle command is given, output is according to slanted
   232 type-writer);
   233 
   234 * support sub/super scripts (for single symbols only), input syntax is
   235 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   236 
   237 * some more standard symbols; see Appendix A of the system manual for
   238 the complete list of symbols defined in isabellesym.sty;
   239 
   240 * improved isabelle style files; more abstract symbol implementation
   241 (should now use \isamath{...} and \isatext{...} in custom symbol
   242 definitions);
   243 
   244 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   245 state; Note that presentation of goal states does not conform to
   246 actual human-readable proof documents.  Please do not include goal
   247 states into document output unless you really know what you are doing!
   248 
   249 * proper indentation of antiquoted output with proportional LaTeX
   250 fonts;
   251 
   252 * no_document ML operator temporarily disables LaTeX document
   253 generation;
   254 
   255 * isatool unsymbolize tunes sources for plain ASCII communication;
   256 
   257 
   258 *** Isar ***
   259 
   260 * Pure: Isar now suffers initial goal statements to contain unbound
   261 schematic variables (this does not conform to actual readable proof
   262 documents, due to unpredictable outcome and non-compositional proof
   263 checking); users who know what they are doing may use schematic goals
   264 for Prolog-style synthesis of proven results;
   265 
   266 * Pure: assumption method (an implicit finishing) now handles actual
   267 rules as well;
   268 
   269 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   270 initial goal, declare "that" only as Pure intro (only for single
   271 steps); the "that" rule assumption may now be involved in implicit
   272 finishing, thus ".." becomes a feasible for trivial obtains;
   273 
   274 * Pure: default proof step now includes 'intro_classes'; thus trivial
   275 instance proofs may be performed by "..";
   276 
   277 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   278 statements as well;
   279 
   280 * Pure: more robust selection of calculational rules;
   281 
   282 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   283 rule (as well as the assumption rule);
   284 
   285 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   286 lemmas, using the graph browser tool;
   287 
   288 * Pure: predict failure of "show" in interactive mode;
   289 
   290 * Pure: 'thms_containing' now takes actual terms as arguments;
   291 
   292 * HOL: improved method 'induct' --- now handles non-atomic goals
   293 (potential INCOMPATIBILITY); tuned error handling;
   294 
   295 * HOL: cases and induct rules now provide explicit hints about the
   296 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   297 any remaining facts are inserted into the goal verbatim;
   298 
   299 * HOL: local contexts (aka cases) may now contain term bindings as
   300 well; the 'cases' and 'induct' methods new provide a ?case binding for
   301 the result to be shown in each case;
   302 
   303 * HOL: added 'recdef_tc' command;
   304 
   305 * isatool convert assists in eliminating legacy ML scripts;
   306 
   307 
   308 *** HOL ***
   309 
   310 * HOL/Library: a collection of generic theories to be used together
   311 with main HOL; the theory loader path already includes this directory
   312 by default; the following existing theories have been moved here:
   313 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   314 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   315 
   316 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   317 modelling and verification task performed in Isabelle/HOL +
   318 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   319 
   320 * HOL/Algebra: special summation operator SUM no longer exists, it has
   321 been replaced by setsum; infix 'assoc' now has priority 50 (like
   322 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   323 'domain', this makes the theory consistent with mathematical
   324 literature;
   325 
   326 * HOL basics: added overloaded operations "inverse" and "divide"
   327 (infix "/"), syntax for generic "abs" operation, generic summation
   328 operator \<Sum>;
   329 
   330 * HOL/typedef: simplified package, provide more useful rules (see also
   331 HOL/subset.thy);
   332 
   333 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   334 now expressed as a proper nested rule (old-style tactic scripts may
   335 require atomize_strip_tac to cope with non-atomic premises);
   336 
   337 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   338 to "split_conv" (old name still available for compatibility);
   339 
   340 * HOL: improved concrete syntax for strings (e.g. allows translation
   341 rules with string literals);
   342 
   343 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   344 and Fleuriot's mechanization of analysis;
   345 
   346 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   347 
   348 
   349 *** CTT ***
   350 
   351 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   352 "lam" is displayed as TWO lambda-symbols
   353 
   354 * CTT: theory Main now available, containing everything (that is, Bool
   355 and Arith);
   356 
   357 
   358 *** General ***
   359 
   360 * Pure: the Simplifier has been implemented properly as a derived rule
   361 outside of the actual kernel (at last!); the overall performance
   362 penalty in practical applications is about 50%, while reliability of
   363 the Isabelle inference kernel has been greatly improved;
   364 
   365 * print modes "brackets" and "no_brackets" control output of nested =>
   366 (types) and ==> (props); the default behaviour is "brackets";
   367 
   368 * Provers: fast_tac (and friends) now handle actual object-logic rules
   369 as assumptions as well;
   370 
   371 * system: support Poly/ML 4.0;
   372 
   373 * system: isatool install handles KDE version 1 or 2;
   374 
   375 
   376 
   377 New in Isabelle99-1 (October 2000)
   378 ----------------------------------
   379 
   380 *** Overview of INCOMPATIBILITIES ***
   381 
   382 * HOL: simplification of natural numbers is much changed; to partly
   383 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   384 issue the following ML commands:
   385 
   386   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   387   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   388 
   389 * HOL: simplification no longer dives into case-expressions; this is
   390 controlled by "t.weak_case_cong" for each datatype t;
   391 
   392 * HOL: nat_less_induct renamed to less_induct;
   393 
   394 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   395 fixsome to patch .thy and .ML sources automatically;
   396 
   397   select_equality  -> some_equality
   398   select_eq_Ex     -> some_eq_ex
   399   selectI2EX       -> someI2_ex
   400   selectI2         -> someI2
   401   selectI          -> someI
   402   select1_equality -> some1_equality
   403   Eps_sym_eq       -> some_sym_eq_trivial
   404   Eps_eq           -> some_eq_trivial
   405 
   406 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   407 
   408 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   409 instead);
   410 
   411 * HOL: the recursion equations generated by 'recdef' are now called
   412 f.simps instead of f.rules;
   413 
   414 * HOL: qed_spec_mp now also handles bounded ALL as well;
   415 
   416 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   417 sometimes be needed;
   418 
   419 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   420 
   421 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   422 
   423 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   424 product is now "<*>" instead of "Times"; the lexicographic product is
   425 now "<*lex*>" instead of "**";
   426 
   427 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   428 of main HOL, but was unused); better use HOL's datatype package;
   429 
   430 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   431 the old syntax may be recovered as follows:
   432 
   433   syntax (symbols)
   434     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   435       (infixl "\\<oplus>" 100)
   436 
   437 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   438 
   439 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   440 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   441 internally;
   442 
   443 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   444 changed from A/r to A//r;
   445 
   446 * ZF: new treatment of arithmetic (nat & int) may break some old
   447 proofs;
   448 
   449 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   450 rulify -> rule_format, elimify -> elim_format, ...);
   451 
   452 * Isar/Provers: intro/elim/dest attributes changed; renamed
   453 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   454 should have to change intro!! to intro? only); replaced "delrule" by
   455 "rule del";
   456 
   457 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   458 
   459 * Provers: strengthened force_tac by using new first_best_tac;
   460 
   461 * LaTeX document preparation: several changes of isabelle.sty (see
   462 lib/texinputs);
   463 
   464 
   465 *** Document preparation ***
   466 
   467 * formal comments (text blocks etc.) in new-style theories may now
   468 contain antiquotations of thm/prop/term/typ/text to be presented
   469 according to latex print mode; concrete syntax is like this:
   470 @{term[show_types] "f(x) = a + x"};
   471 
   472 * isatool mkdir provides easy setup of Isabelle session directories,
   473 including proper document sources;
   474 
   475 * generated LaTeX sources are now deleted after successful run
   476 (isatool document -c); may retain a copy somewhere else via -D option
   477 of isatool usedir;
   478 
   479 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   480 style files, achieving self-contained LaTeX sources and simplifying
   481 LaTeX debugging;
   482 
   483 * old-style theories now produce (crude) LaTeX output as well;
   484 
   485 * browser info session directories are now self-contained (may be put
   486 on WWW server seperately); improved graphs of nested sessions; removed
   487 graph for 'all sessions';
   488 
   489 * several improvements in isabelle style files; \isabellestyle{it}
   490 produces fake math mode output; \isamarkupheader is now \section by
   491 default; see lib/texinputs/isabelle.sty etc.;
   492 
   493 
   494 *** Isar ***
   495 
   496 * Isar/Pure: local results and corresponding term bindings are now
   497 subject to Hindley-Milner polymorphism (similar to ML); this
   498 accommodates incremental type-inference very nicely;
   499 
   500 * Isar/Pure: new derived language element 'obtain' supports
   501 generalized existence reasoning;
   502 
   503 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   504 support accumulation of results, without applying any rules yet;
   505 useful to collect intermediate results without explicit name
   506 references, and for use with transitivity rules with more than 2
   507 premises;
   508 
   509 * Isar/Pure: scalable support for case-analysis type proofs: new
   510 'case' language element refers to local contexts symbolically, as
   511 produced by certain proof methods; internally, case names are attached
   512 to theorems as "tags";
   513 
   514 * Isar/Pure: theory command 'hide' removes declarations from
   515 class/type/const name spaces;
   516 
   517 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   518 indicate potential overloading;
   519 
   520 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   521 
   522 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   523 "{a,b,c}" instead of {a,b,c};
   524 
   525 * Isar/Pure now provides its own version of intro/elim/dest
   526 attributes; useful for building new logics, but beware of confusion
   527 with the version in Provers/classical;
   528 
   529 * Isar/Pure: the local context of (non-atomic) goals is provided via
   530 case name 'antecedent';
   531 
   532 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   533 to the current context is now done automatically);
   534 
   535 * Isar/Pure: theory command 'method_setup' provides a simple interface
   536 for definining proof methods in ML;
   537 
   538 * Isar/Provers: intro/elim/dest attributes changed; renamed
   539 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   540 most cases, one should have to change intro!! to intro? only);
   541 replaced "delrule" by "rule del";
   542 
   543 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   544 'symmetric' attribute (the latter supercedes [RS sym]);
   545 
   546 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   547 method modifier); 'simp' method: 'only:' modifier removes loopers as
   548 well (including splits);
   549 
   550 * Isar/Provers: Simplifier and Classical methods now support all kind
   551 of modifiers used in the past, including 'cong', 'iff', etc.
   552 
   553 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   554 of Simplifier and Classical reasoner);
   555 
   556 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   557 now support named cases; major packages (inductive, datatype, primrec,
   558 recdef) support case names and properly name parameters;
   559 
   560 * Isar/HOL: new transitivity rules for substitution in inequalities --
   561 monotonicity conditions are extracted to be proven at end of
   562 calculations;
   563 
   564 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   565 method anyway;
   566 
   567 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   568 split_if split_if_asm; datatype package provides theorems foo.splits =
   569 foo.split foo.split_asm for each datatype;
   570 
   571 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   572 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   573 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   574 use "(cases (simplified))" method in proper proof texts);
   575 
   576 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   577 
   578 * Isar: names of theorems etc. may be natural numbers as well;
   579 
   580 * Isar: 'pr' command: optional arguments for goals_limit and
   581 ProofContext.prems_limit; no longer prints theory contexts, but only
   582 proof states;
   583 
   584 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   585 additional print modes to be specified; e.g. "pr(latex)" will print
   586 proof state according to the Isabelle LaTeX style;
   587 
   588 * Isar: improved support for emulating tactic scripts, including proof
   589 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   590 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   591 (for HOL datatypes);
   592 
   593 * Isar: simplified (more robust) goal selection of proof methods: 1st
   594 goal, all goals, or explicit goal specifier (tactic emulation); thus
   595 'proof method scripts' have to be in depth-first order;
   596 
   597 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   598 
   599 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   600 should instead use individual commands for printing items
   601 (print_commands, print_methods etc.);
   602 
   603 * Isar: added 'nothing' --- the empty list of theorems;
   604 
   605 
   606 *** HOL ***
   607 
   608 * HOL/MicroJava: formalization of a fragment of Java, together with a
   609 corresponding virtual machine and a specification of its bytecode
   610 verifier and a lightweight bytecode verifier, including proofs of
   611 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   612 Cornelia Pusch (see also the homepage of project Bali at
   613 http://isabelle.in.tum.de/Bali/);
   614 
   615 * HOL/Algebra: new theory of rings and univariate polynomials, by
   616 Clemens Ballarin;
   617 
   618 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   619 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   620 Rasmussen;
   621 
   622 * HOL/Lattice: fundamental concepts of lattice theory and order
   623 structures, including duals, properties of bounds versus algebraic
   624 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   625 Theorem for complete lattices etc.; may also serve as a demonstration
   626 for abstract algebraic reasoning using axiomatic type classes, and
   627 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   628 
   629 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   630 von Oheimb;
   631 
   632 * HOL/IMPP: extension of IMP with local variables and mutually
   633 recursive procedures, by David von Oheimb;
   634 
   635 * HOL/Lambda: converted into new-style theory and document;
   636 
   637 * HOL/ex/Multiquote: example of multiple nested quotations and
   638 anti-quotations -- basically a generalized version of de-Bruijn
   639 representation; very useful in avoiding lifting of operations;
   640 
   641 * HOL/record: added general record equality rule to simpset; fixed
   642 select-update simplification procedure to handle extended records as
   643 well; admit "r" as field name;
   644 
   645 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   646 other numeric types and also as the identity of groups, rings, etc.;
   647 
   648 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   649 Types nat and int belong to this axclass;
   650 
   651 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   652    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   653    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   654   two terms #m*u and #n*u are replaced by #(m+n)*u
   655     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   656   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   657     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   658 
   659 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   660 powerful prover for predicate logic but knows nothing of clasets; see
   661 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   662 
   663 * HOL: new version of "case_tac" subsumes both boolean case split and
   664 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   665 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   666 
   667 * HOL: simplification no longer dives into case-expressions: only the
   668 selector expression is simplified, but not the remaining arms; to
   669 enable full simplification of case-expressions for datatype t, you may
   670 remove t.weak_case_cong from the simpset, either globally (Delcongs
   671 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   672 
   673 * HOL/recdef: the recursion equations generated by 'recdef' for
   674 function 'f' are now called f.simps instead of f.rules; if all
   675 termination conditions are proved automatically, these simplification
   676 rules are added to the simpset, as in primrec; rules may be named
   677 individually as well, resulting in a separate list of theorems for
   678 each equation;
   679 
   680 * HOL/While is a new theory that provides a while-combinator. It
   681 permits the definition of tail-recursive functions without the
   682 provision of a termination measure. The latter is necessary once the
   683 invariant proof rule for while is applied.
   684 
   685 * HOL: new (overloaded) notation for the set of elements below/above
   686 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   687 
   688 * HOL: theorems impI, allI, ballI bound as "strip";
   689 
   690 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   691 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   692 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   693 
   694 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   695 
   696 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   697 main HOL, but was unused);
   698 
   699 * HOL: fewer consts declared as global (e.g. have to refer to
   700 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   701 
   702 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   703 in case of overlap with user translations (e.g. judgements over
   704 tuples); (note that the underlying logical represenation is still
   705 bogus);
   706 
   707 
   708 *** ZF ***
   709 
   710 * ZF: simplification automatically cancels common terms in arithmetic
   711 expressions over nat and int;
   712 
   713 * ZF: new treatment of nat to minimize type-checking: all operators
   714 coerce their operands to a natural number using the function natify,
   715 making the algebraic laws unconditional;
   716 
   717 * ZF: as above, for int: operators coerce their operands to an integer
   718 using the function intify;
   719 
   720 * ZF: the integer library now contains many of the usual laws for the
   721 orderings, including $<=, and monotonicity laws for $+ and $*;
   722 
   723 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   724 simplification;
   725 
   726 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   727 to the simplifier and classical reasoner simultaneously;
   728 
   729 
   730 *** General ***
   731 
   732 * Provers: blast_tac now handles actual object-logic rules as
   733 assumptions; note that auto_tac uses blast_tac internally as well;
   734 
   735 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   736 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   737 
   738 * Provers: delrules now handles destruct rules as well (no longer need
   739 explicit make_elim);
   740 
   741 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   742   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   743 use instead the strong form,
   744   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   745 in HOL, FOL and ZF the function cla_make_elim will create such rules
   746 from destruct-rules;
   747 
   748 * Provers: Simplifier.easy_setup provides a fast path to basic
   749 Simplifier setup for new object-logics;
   750 
   751 * Pure: AST translation rules no longer require constant head on LHS;
   752 
   753 * Pure: improved name spaces: ambiguous output is qualified; support
   754 for hiding of names;
   755 
   756 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   757 XSYMBOL_HOME; no longer need to do manual configuration in most
   758 situations;
   759 
   760 * system: compression of ML heaps images may now be controlled via -c
   761 option of isabelle and isatool usedir (currently only observed by
   762 Poly/ML);
   763 
   764 * system: isatool installfonts may handle X-Symbol fonts as well (very
   765 useful for remote X11);
   766 
   767 * system: provide TAGS file for Isabelle sources;
   768 
   769 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   770 order;
   771 
   772 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   773 timing flag supersedes proof_timing and Toplevel.trace;
   774 
   775 * ML: new combinators |>> and |>>> for incremental transformations
   776 with secondary results (e.g. certain theory extensions):
   777 
   778 * ML: PureThy.add_defs gets additional argument to indicate potential
   779 overloading (usually false);
   780 
   781 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   782 results;
   783 
   784 
   785 
   786 New in Isabelle99 (October 1999)
   787 --------------------------------
   788 
   789 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   790 
   791 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   792 are no longer simplified.  (This allows the simplifier to unfold recursive
   793 functional programs.)  To restore the old behaviour, declare
   794 
   795     Delcongs [if_weak_cong];
   796 
   797 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   798 complement;
   799 
   800 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   801 
   802 * HOL/datatype: mutual_induct_tac no longer exists --
   803   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   804 
   805 * HOL/typedef: fixed type inference for representing set; type
   806 arguments now have to occur explicitly on the rhs as type constraints;
   807 
   808 * ZF: The con_defs part of an inductive definition may no longer refer
   809 to constants declared in the same theory;
   810 
   811 * HOL, ZF: the function mk_cases, generated by the inductive
   812 definition package, has lost an argument.  To simplify its result, it
   813 uses the default simpset instead of a supplied list of theorems.
   814 
   815 * HOL/List: the constructors of type list are now Nil and Cons;
   816 
   817 * Simplifier: the type of the infix ML functions
   818         setSSolver addSSolver setSolver addSolver
   819 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   820 for packaging solvers. A solver is created via
   821         mk_solver: string -> (thm list -> int -> tactic) -> solver
   822 where the string argument is only a comment.
   823 
   824 
   825 *** Proof tools ***
   826 
   827 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   828 decision procedure for linear arithmetic. Currently it is used for
   829 types `nat', `int', and `real' in HOL (see below); it can, should and
   830 will be instantiated for other types and logics as well.
   831 
   832 * The simplifier now accepts rewrite rules with flexible heads, eg
   833      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   834   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   835   matching.
   836 
   837 
   838 *** General ***
   839 
   840 * New Isabelle/Isar subsystem provides an alternative to traditional
   841 tactical theorem proving; together with the ProofGeneral/isar user
   842 interface it offers an interactive environment for developing human
   843 readable proof documents (Isar == Intelligible semi-automated
   844 reasoning); for further information see isatool doc isar-ref,
   845 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   846 
   847 * improved and simplified presentation of theories: better HTML markup
   848 (including colors), graph views in several sizes; isatool usedir now
   849 provides a proper interface for user theories (via -P option); actual
   850 document preparation based on (PDF)LaTeX is available as well (for
   851 new-style theories only); see isatool doc system for more information;
   852 
   853 * native support for Proof General, both for classic Isabelle and
   854 Isabelle/Isar;
   855 
   856 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   857 using the graph browser tool;
   858 
   859 * Isabelle manuals now also available as PDF;
   860 
   861 * theory loader rewritten from scratch (may not be fully
   862 bug-compatible); old loadpath variable has been replaced by show_path,
   863 add_path, del_path, reset_path functions; new operations such as
   864 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   865 isatool doc ref);
   866 
   867 * improved isatool install: option -k creates KDE application icon,
   868 option -p DIR installs standalone binaries;
   869 
   870 * added ML_PLATFORM setting (useful for cross-platform installations);
   871 more robust handling of platform specific ML images for SML/NJ;
   872 
   873 * the settings environment is now statically scoped, i.e. it is never
   874 created again in sub-processes invoked from isabelle, isatool, or
   875 Isabelle;
   876 
   877 * path element specification '~~' refers to '$ISABELLE_HOME';
   878 
   879 * in locales, the "assumes" and "defines" parts may be omitted if
   880 empty;
   881 
   882 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   883 long arrows);
   884 
   885 * new print_mode "HTML";
   886 
   887 * new flag show_tags controls display of tags of theorems (which are
   888 basically just comments that may be attached by some tools);
   889 
   890 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   891 mode and goal output format:
   892 
   893 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   894 244c244
   895 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   896 ---
   897 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   898 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   899 181c181
   900 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   901 ---
   902 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   903 
   904 * function bind_thms stores lists of theorems (cf. bind_thm);
   905 
   906 * new shorthand tactics ftac, eatac, datac, fatac;
   907 
   908 * qed (and friends) now accept "" as result name; in that case the
   909 theorem is not stored, but proper checks and presentation of the
   910 result still apply;
   911 
   912 * theorem database now also indexes constants "Trueprop", "all",
   913 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   914 
   915 
   916 *** HOL ***
   917 
   918 ** HOL arithmetic **
   919 
   920 * There are now decision procedures for linear arithmetic over nat and
   921 int:
   922 
   923 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   924 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   925 are treated as atomic; subformulae not involving type `nat' or `int'
   926 are ignored; quantified subformulae are ignored unless they are
   927 positive universal or negative existential. The tactic has to be
   928 invoked by hand and can be a little bit slow. In particular, the
   929 running time is exponential in the number of occurrences of `min' and
   930 `max', and `-' on `nat'.
   931 
   932 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   933 (negated) (in)equalities among the premises and the conclusion into
   934 account (i.e. no compound formulae) and does not know about `min' and
   935 `max', and `-' on `nat'. It is fast and is used automatically by the
   936 simplifier.
   937 
   938 NB: At the moment, these decision procedures do not cope with mixed
   939 nat/int formulae where the two parts interact, such as `m < n ==>
   940 int(m) < int(n)'.
   941 
   942 * HOL/Numeral provides a generic theory of numerals (encoded
   943 efficiently as bit strings); setup for types nat/int/real is in place;
   944 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   945 int, existing theories and proof scripts may require a few additional
   946 type constraints;
   947 
   948 * integer division and remainder can now be performed on constant
   949 arguments;
   950 
   951 * many properties of integer multiplication, division and remainder
   952 are now available;
   953 
   954 * An interface to the Stanford Validity Checker (SVC) is available through the
   955 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   956 are proved automatically.  SVC must be installed separately, and its results
   957 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   958 invocation of the underlying oracle).  For SVC see
   959   http://verify.stanford.edu/SVC
   960 
   961 * IsaMakefile: the HOL-Real target now builds an actual image;
   962 
   963 
   964 ** HOL misc **
   965 
   966 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   967 (in Isabelle/Isar) -- by Gertrud Bauer;
   968 
   969 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   970 analysis for assembly languages with subtypes;
   971 
   972 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   973 -- avoids syntactic ambiguities and treats state, transition, and
   974 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   975 changed syntax and (many) tactics;
   976 
   977 * HOL/inductive: Now also handles more general introduction rules such
   978   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   979   theorems are now maintained within the theory (maintained via the
   980   "mono" attribute);
   981 
   982 * HOL/datatype: Now also handles arbitrarily branching datatypes
   983   (using function types) such as
   984 
   985   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   986 
   987 * HOL/record: record_simproc (part of the default simpset) takes care
   988 of selectors applied to updated records; record_split_tac is no longer
   989 part of the default claset; update_defs may now be removed from the
   990 simpset in many cases; COMPATIBILITY: old behavior achieved by
   991 
   992   claset_ref () := claset() addSWrapper record_split_wrapper;
   993   Delsimprocs [record_simproc]
   994 
   995 * HOL/typedef: fixed type inference for representing set; type
   996 arguments now have to occur explicitly on the rhs as type constraints;
   997 
   998 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   999 names rather than an ML expression;
  1000 
  1001 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1002 supplied later.  Program schemes can be defined, such as
  1003     "While B C s = (if B s then While B C (C s) else s)"
  1004 where the well-founded relation can be chosen after B and C have been given.
  1005 
  1006 * HOL/List: the constructors of type list are now Nil and Cons;
  1007 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1008 course, ML tools referring to List.list.op # etc. have to be adapted;
  1009 
  1010 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1011 disabled by default; run isabelle with option -m HOL to get back to
  1012 the original Gordon/HOL-style output;
  1013 
  1014 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1015 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1016 
  1017 * HOL basic syntax simplified (more orthogonal): all variants of
  1018 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1019 Eps operator is provided as well: "SOME x. P[x]";
  1020 
  1021 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1022 
  1023 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1024 thus available for user theories;
  1025 
  1026 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1027 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1028 time;
  1029 
  1030 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1031 several times and then mp;
  1032 
  1033 
  1034 *** LK ***
  1035 
  1036 * the notation <<...>> is now available as a notation for sequences of
  1037 formulas;
  1038 
  1039 * the simplifier is now installed
  1040 
  1041 * the axiom system has been generalized (thanks to Soren Heilmann)
  1042 
  1043 * the classical reasoner now has a default rule database
  1044 
  1045 
  1046 *** ZF ***
  1047 
  1048 * new primrec section allows primitive recursive functions to be given
  1049 directly (as in HOL) over datatypes and the natural numbers;
  1050 
  1051 * new tactics induct_tac and exhaust_tac for induction (or case
  1052 analysis) over datatypes and the natural numbers;
  1053 
  1054 * the datatype declaration of type T now defines the recursor T_rec;
  1055 
  1056 * simplification automatically does freeness reasoning for datatype
  1057 constructors;
  1058 
  1059 * automatic type-inference, with AddTCs command to insert new
  1060 type-checking rules;
  1061 
  1062 * datatype introduction rules are now added as Safe Introduction rules
  1063 to the claset;
  1064 
  1065 * the syntax "if P then x else y" is now available in addition to
  1066 if(P,x,y);
  1067 
  1068 
  1069 *** Internal programming interfaces ***
  1070 
  1071 * tuned simplifier trace output; new flag debug_simp;
  1072 
  1073 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1074 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1075 
  1076 * AxClass.axclass_tac lost the theory argument;
  1077 
  1078 * tuned current_goals_markers semantics: begin / end goal avoids
  1079 printing empty lines;
  1080 
  1081 * removed prs and prs_fn hook, which was broken because it did not
  1082 include \n in its semantics, forcing writeln to add one
  1083 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1084 string -> unit if you really want to output text without newline;
  1085 
  1086 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1087 plain output, interface builders may have to enable 'isabelle_font'
  1088 mode to get Isabelle font glyphs as before;
  1089 
  1090 * refined token_translation interface; INCOMPATIBILITY: output length
  1091 now of type real instead of int;
  1092 
  1093 * theory loader actions may be traced via new ThyInfo.add_hook
  1094 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1095 your own database of information attached to *whole* theories -- as
  1096 opposed to intra-theory data slots offered via TheoryDataFun;
  1097 
  1098 * proper handling of dangling sort hypotheses (at last!);
  1099 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1100 extra sort hypotheses that can be witnessed from the type signature;
  1101 the force_strip_shyps flag is gone, any remaining shyps are simply
  1102 left in the theorem (with a warning issued by strip_shyps_warning);
  1103 
  1104 
  1105 
  1106 New in Isabelle98-1 (October 1998)
  1107 ----------------------------------
  1108 
  1109 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1110 
  1111 * several changes of automated proof tools;
  1112 
  1113 * HOL: major changes to the inductive and datatype packages, including
  1114 some minor incompatibilities of theory syntax;
  1115 
  1116 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1117 called `inj_on';
  1118 
  1119 * HOL: removed duplicate thms in Arith:
  1120   less_imp_add_less  should be replaced by  trans_less_add1
  1121   le_imp_add_le      should be replaced by  trans_le_add1
  1122 
  1123 * HOL: unary minus is now overloaded (new type constraints may be
  1124 required);
  1125 
  1126 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1127 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1128 now taken as an integer constant.
  1129 
  1130 * Pure: ML function 'theory_of' renamed to 'theory';
  1131 
  1132 
  1133 *** Proof tools ***
  1134 
  1135 * Simplifier:
  1136   1. Asm_full_simp_tac is now more aggressive.
  1137      1. It will sometimes reorient premises if that increases their power to
  1138         simplify.
  1139      2. It does no longer proceed strictly from left to right but may also
  1140         rotate premises to achieve further simplification.
  1141      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1142      old Asm_full_simp_tac in that it does not rotate premises.
  1143   2. The simplifier now knows a little bit about nat-arithmetic.
  1144 
  1145 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1146 allows for selected deletion of wrappers, by introduction of names for
  1147 wrapper functionals.  This implies that addbefore, addSbefore,
  1148 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1149 and that adding two tactics with the same name overwrites the first
  1150 one (emitting a warning).
  1151   type wrapper = (int -> tactic) -> (int -> tactic)
  1152   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1153   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1154   delWrapper, delSWrapper: claset *  string            -> claset
  1155   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1156 
  1157 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1158 semantics; addbefore now affects only the unsafe part of step_tac
  1159 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1160 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1161 by Force_tac;
  1162 
  1163 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1164 compWrapper; added safe wrapper (and access functions for it);
  1165 
  1166 * HOL/split_all_tac is now much faster and fails if there is nothing
  1167 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1168 and the names of the automatically generated variables have changed.
  1169 split_all_tac has moved within claset() from unsafe wrappers to safe
  1170 wrappers, which means that !!-bound variables are split much more
  1171 aggressively, and safe_tac and clarify_tac now split such variables.
  1172 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1173 Note: the same holds for record_split_tac, which does the job of
  1174 split_all_tac for record fields.
  1175 
  1176 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1177 permanently to the default simpset using Addsplits just like
  1178 Addsimps. They can be removed via Delsplits just like
  1179 Delsimps. Lower-case versions are also available.
  1180 
  1181 * HOL/Simplifier: The rule split_if is now part of the default
  1182 simpset. This means that the simplifier will eliminate all occurrences
  1183 of if-then-else in the conclusion of a goal. To prevent this, you can
  1184 either remove split_if completely from the default simpset by
  1185 `Delsplits [split_if]' or remove it in a specific call of the
  1186 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1187 other case splitting rules to/from the default simpset: every datatype
  1188 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1189 t is the name of the datatype).
  1190 
  1191 * Classical reasoner / Simplifier combination: new force_tac (and
  1192 derivatives Force_tac, force) combines rewriting and classical
  1193 reasoning (and whatever other tools) similarly to auto_tac, but is
  1194 aimed to solve the given subgoal completely.
  1195 
  1196 
  1197 *** General ***
  1198 
  1199 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1200 and `goalw': the theory is no longer needed as an explicit argument -
  1201 the current theory context is used; assumptions are no longer returned
  1202 at the ML-level unless one of them starts with ==> or !!; it is
  1203 recommended to convert to these new commands using isatool fixgoal
  1204 (backup your sources first!);
  1205 
  1206 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1207 the current theory context, and 'theory' to lookup stored theories;
  1208 
  1209 * new theory section 'locale' for declaring constants, assumptions and
  1210 definitions that have local scope;
  1211 
  1212 * new theory section 'nonterminals' for purely syntactic types;
  1213 
  1214 * new theory section 'setup' for generic ML setup functions
  1215 (e.g. package initialization);
  1216 
  1217 * the distribution now includes Isabelle icons: see
  1218 lib/logo/isabelle-{small,tiny}.xpm;
  1219 
  1220 * isatool install - install binaries with absolute references to
  1221 ISABELLE_HOME/bin;
  1222 
  1223 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1224 
  1225 * print mode 'emacs' reserved for Isamode;
  1226 
  1227 * support multiple print (ast) translations per constant name;
  1228 
  1229 * theorems involving oracles are now printed with a suffixed [!];
  1230 
  1231 
  1232 *** HOL ***
  1233 
  1234 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1235 
  1236 * HOL/inductive package reorganized and improved: now supports mutual
  1237 definitions such as
  1238 
  1239   inductive EVEN ODD
  1240     intrs
  1241       null "0 : EVEN"
  1242       oddI "n : EVEN ==> Suc n : ODD"
  1243       evenI "n : ODD ==> Suc n : EVEN"
  1244 
  1245 new theorem list "elims" contains an elimination rule for each of the
  1246 recursive sets; inductive definitions now handle disjunctive premises
  1247 correctly (also ZF);
  1248 
  1249 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1250 "mutual_induct" no longer exists - the induction rule is always
  1251 contained in "induct";
  1252 
  1253 
  1254 * HOL/datatype package re-implemented and greatly improved: now
  1255 supports mutually recursive datatypes such as
  1256 
  1257   datatype
  1258     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1259             | SUM ('a aexp) ('a aexp)
  1260             | DIFF ('a aexp) ('a aexp)
  1261             | NUM 'a
  1262   and
  1263     'a bexp = LESS ('a aexp) ('a aexp)
  1264             | AND ('a bexp) ('a bexp)
  1265             | OR ('a bexp) ('a bexp)
  1266 
  1267 as well as indirectly recursive datatypes such as
  1268 
  1269   datatype
  1270     ('a, 'b) term = Var 'a
  1271                   | App 'b ((('a, 'b) term) list)
  1272 
  1273 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1274 induction on mutually / indirectly recursive datatypes.
  1275 
  1276 Primrec equations are now stored in theory and can be accessed via
  1277 <function_name>.simps.
  1278 
  1279 INCOMPATIBILITIES:
  1280 
  1281   - Theories using datatypes must now have theory Datatype as an
  1282     ancestor.
  1283   - The specific <typename>.induct_tac no longer exists - use the
  1284     generic induct_tac instead.
  1285   - natE has been renamed to nat.exhaust - use exhaust_tac
  1286     instead of res_inst_tac ... natE. Note that the variable
  1287     names in nat.exhaust differ from the names in natE, this
  1288     may cause some "fragile" proofs to fail.
  1289   - The theorems split_<typename>_case and split_<typename>_case_asm
  1290     have been renamed to <typename>.split and <typename>.split_asm.
  1291   - Since default sorts of type variables are now handled correctly,
  1292     some datatype definitions may have to be annotated with explicit
  1293     sort constraints.
  1294   - Primrec definitions no longer require function name and type
  1295     of recursive argument.
  1296 
  1297 Consider using isatool fixdatatype to adapt your theories and proof
  1298 scripts to the new package (backup your sources first!).
  1299 
  1300 
  1301 * HOL/record package: considerably improved implementation; now
  1302 includes concrete syntax for record types, terms, updates; theorems
  1303 for surjective pairing and splitting !!-bound record variables; proof
  1304 support is as follows:
  1305 
  1306   1) standard conversions (selectors or updates applied to record
  1307 constructor terms) are part of the standard simpset;
  1308 
  1309   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1310 made part of standard simpset and claset via addIffs;
  1311 
  1312   3) a tactic for record field splitting (record_split_tac) is part of
  1313 the standard claset (addSWrapper);
  1314 
  1315 To get a better idea about these rules you may retrieve them via
  1316 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1317 the name of your record type.
  1318 
  1319 The split tactic 3) conceptually simplifies by the following rule:
  1320 
  1321   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1322 
  1323 Thus any record variable that is bound by meta-all will automatically
  1324 blow up into some record constructor term, consequently the
  1325 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1326 solve record problems automatically.
  1327 
  1328 
  1329 * reorganized the main HOL image: HOL/Integ and String loaded by
  1330 default; theory Main includes everything;
  1331 
  1332 * automatic simplification of integer sums and comparisons, using cancellation;
  1333 
  1334 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1335 
  1336 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1337 
  1338 * many new identities for unions, intersections, set difference, etc.;
  1339 
  1340 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1341 called split_if, split_split, split_sum_case and split_nat_case (to go
  1342 with add/delsplits);
  1343 
  1344 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1345 (?x::unit) = (); this is made part of the default simpset, which COULD
  1346 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1347 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1348 unit_abs_eta_conv is added in order to counter the effect of
  1349 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1350 %u.f();
  1351 
  1352 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1353 makes more sense);
  1354 
  1355 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1356   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1357   disjointness reasoning but breaking a few old proofs.
  1358 
  1359 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1360 to 'converse' from 'inverse' (for compatibility with ZF and some
  1361 literature);
  1362 
  1363 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1364 the well-founded relation;
  1365 
  1366 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1367     Compl A.  The "Compl" syntax remains available as input syntax for this
  1368     release ONLY.
  1369 
  1370 * HOL/Update: new theory of function updates:
  1371     f(a:=b) == %x. if x=a then b else f x
  1372 may also be iterated as in f(a:=b,c:=d,...);
  1373 
  1374 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1375 
  1376 * HOL/List:
  1377   - new function list_update written xs[i:=v] that updates the i-th
  1378     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1379   - new function `upt' written [i..j(] which generates the list
  1380     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1381     bound write [i..j], which is a shorthand for [i..j+1(].
  1382   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1383 
  1384 * HOL/Arith:
  1385   - removed 'pred' (predecessor) function;
  1386   - generalized some theorems about n-1;
  1387   - many new laws about "div" and "mod";
  1388   - new laws about greatest common divisors (see theory ex/Primes);
  1389 
  1390 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1391 instead of "inverse";
  1392 
  1393 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1394   of the multiset ordering;
  1395 
  1396 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1397   (not included by default);
  1398 
  1399 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1400 
  1401 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1402   programs, i.e. different program variables may have different types.
  1403 
  1404 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1405   [previously, this check worked only if the rewrite rule was unconditional]
  1406   Now rew can involve either definitions or equalities (either == or =).
  1407 
  1408 
  1409 *** ZF ***
  1410 
  1411 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1412   only the theorems proved on ZF.ML;
  1413 
  1414 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1415   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1416   disjointness reasoning but breaking a few old proofs.
  1417 
  1418 * ZF/Update: new theory of function updates
  1419     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1420   may also be iterated as in f(a:=b,c:=d,...);
  1421 
  1422 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1423 
  1424 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1425   [previously, this check worked only if the rewrite rule was unconditional]
  1426   Now rew can involve either definitions or equalities (either == or =).
  1427 
  1428 * case_tac provided for compatibility with HOL
  1429     (like the old excluded_middle_tac, but with subgoals swapped)
  1430 
  1431 
  1432 *** Internal programming interfaces ***
  1433 
  1434 * Pure: several new basic modules made available for general use, see
  1435 also src/Pure/README;
  1436 
  1437 * improved the theory data mechanism to support encapsulation (data
  1438 kind name replaced by private Object.kind, acting as authorization
  1439 key); new type-safe user interface via functor TheoryDataFun; generic
  1440 print_data function becomes basically useless;
  1441 
  1442 * removed global_names compatibility flag -- all theory declarations
  1443 are qualified by default;
  1444 
  1445 * module Pure/Syntax now offers quote / antiquote translation
  1446 functions (useful for Hoare logic etc. with implicit dependencies);
  1447 see HOL/ex/Antiquote for an example use;
  1448 
  1449 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1450 cterm -> thm;
  1451 
  1452 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1453 subgoal;
  1454 
  1455 * Display.print_goals function moved to Locale.print_goals;
  1456 
  1457 * standard print function for goals supports current_goals_markers
  1458 variable for marking begin of proof, end of proof, start of goal; the
  1459 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1460 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1461 for example;
  1462 
  1463 
  1464 
  1465 New in Isabelle98 (January 1998)
  1466 --------------------------------
  1467 
  1468 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1469 
  1470 * changed lexical syntax of terms / types: dots made part of long
  1471 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1472 
  1473 * simpset (and claset) reference variable replaced by functions
  1474 simpset / simpset_ref;
  1475 
  1476 * no longer supports theory aliases (via merge) and non-trivial
  1477 implicit merge of thms' signatures;
  1478 
  1479 * most internal names of constants changed due to qualified names;
  1480 
  1481 * changed Pure/Sequence interface (see Pure/seq.ML);
  1482 
  1483 
  1484 *** General Changes ***
  1485 
  1486 * hierachically structured name spaces (for consts, types, axms, thms
  1487 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1488 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1489 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1490 long_names for fully qualified output names; NOTE: ML programs
  1491 (special tactics, packages etc.) referring to internal names may have
  1492 to be adapted to cope with fully qualified names; in case of severe
  1493 backward campatibility problems try setting 'global_names' at compile
  1494 time to have enrything declared within a flat name space; one may also
  1495 fine tune name declarations in theories via the 'global' and 'local'
  1496 section;
  1497 
  1498 * reimplemented the implicit simpset and claset using the new anytype
  1499 data filed in signatures; references simpset:simpset ref etc. are
  1500 replaced by functions simpset:unit->simpset and
  1501 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1502 to patch your ML files accordingly;
  1503 
  1504 * HTML output now includes theory graph data for display with Java
  1505 applet or isatool browser; data generated automatically via isatool
  1506 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1507 
  1508 * defs may now be conditional; improved rewrite_goals_tac to handle
  1509 conditional equations;
  1510 
  1511 * defs now admits additional type arguments, using TYPE('a) syntax;
  1512 
  1513 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1514 creates a new theory node; implicit merge of thms' signatures is
  1515 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1516 transfer:theory->thm->thm in (rare) cases;
  1517 
  1518 * improved handling of draft signatures / theories; draft thms (and
  1519 ctyps, cterms) are automatically promoted to real ones;
  1520 
  1521 * slightly changed interfaces for oracles: admit many per theory, named
  1522 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1523 
  1524 * print_goals: optional output of const types (set show_consts and
  1525 show_types);
  1526 
  1527 * improved output of warnings (###) and errors (***);
  1528 
  1529 * subgoal_tac displays a warning if the new subgoal has type variables;
  1530 
  1531 * removed old README and Makefiles;
  1532 
  1533 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1534 
  1535 * removed obsolete init_pps and init_database;
  1536 
  1537 * deleted the obsolete tactical STATE, which was declared by
  1538     fun STATE tacfun st = tacfun st st;
  1539 
  1540 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1541 (which abbreviates $HOME);
  1542 
  1543 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1544 use isatool fixseq to adapt your ML programs (this works for fully
  1545 qualified references to the Sequence structure only!);
  1546 
  1547 * use_thy no longer requires writable current directory; it always
  1548 reloads .ML *and* .thy file, if either one is out of date;
  1549 
  1550 
  1551 *** Classical Reasoner ***
  1552 
  1553 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1554 tactics that use classical reasoning to simplify a subgoal without
  1555 splitting it into several subgoals;
  1556 
  1557 * Safe_tac: like safe_tac but uses the default claset;
  1558 
  1559 
  1560 *** Simplifier ***
  1561 
  1562 * added simplification meta rules:
  1563     (asm_)(full_)simplify: simpset -> thm -> thm;
  1564 
  1565 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1566 logics (again);
  1567 
  1568 * added prems argument to simplification procedures;
  1569 
  1570 * HOL, FOL, ZF: added infix function `addsplits':
  1571   instead of `<simpset> setloop (split_tac <thms>)'
  1572   you can simply write `<simpset> addsplits <thms>'
  1573 
  1574 
  1575 *** Syntax ***
  1576 
  1577 * TYPE('a) syntax for type reflection terms;
  1578 
  1579 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1580 
  1581 * pretty printer: changed order of mixfix annotation preference (again!);
  1582 
  1583 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1584 
  1585 
  1586 *** HOL ***
  1587 
  1588 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1589   with `addloop' of the simplifier to faciliate case splitting in premises.
  1590 
  1591 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1592 
  1593 * HOL/Auth: new protocol proofs including some for the Internet
  1594   protocol TLS;
  1595 
  1596 * HOL/Map: new theory of `maps' a la VDM;
  1597 
  1598 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1599 cancelling out common nat summands from =, <, <= (in)equalities, or
  1600 differences; simplification procedures nat_cancel_factor for
  1601 cancelling common factor from =, <, <= (in)equalities over natural
  1602 sums; nat_cancel contains both kinds of procedures, it is installed by
  1603 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1604 
  1605 * HOL/simplifier: terms of the form
  1606   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1607   are rewritten to
  1608   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1609   and those of the form
  1610   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1611   are rewritten to
  1612   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1613 
  1614 * HOL/datatype
  1615   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1616 
  1617   P(t_case f1 ... fn x) =
  1618      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1619         ...
  1620        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1621      )
  1622 
  1623   and a theorem `split_t_case_asm' of the form
  1624 
  1625   P(t_case f1 ... fn x) =
  1626     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1627         ...
  1628        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1629      )
  1630   which can be added to a simpset via `addsplits'. The existing theorems
  1631   expand_list_case and expand_option_case have been renamed to
  1632   split_list_case and split_option_case.
  1633 
  1634 * HOL/Arithmetic:
  1635   - `pred n' is automatically converted to `n-1'.
  1636     Users are strongly encouraged not to use `pred' any longer,
  1637     because it will disappear altogether at some point.
  1638   - Users are strongly encouraged to write "0 < n" rather than
  1639     "n ~= 0". Theorems and proof tools have been modified towards this
  1640     `standard'.
  1641 
  1642 * HOL/Lists:
  1643   the function "set_of_list" has been renamed "set" (and its theorems too);
  1644   the function "nth" now takes its arguments in the reverse order and
  1645   has acquired the infix notation "!" as in "xs!n".
  1646 
  1647 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1648 
  1649 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1650   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1651 
  1652 * HOL/record: extensible records with schematic structural subtyping
  1653 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1654 still lacks various theorems and concrete record syntax;
  1655 
  1656 
  1657 *** HOLCF ***
  1658 
  1659 * removed "axioms" and "generated by" sections;
  1660 
  1661 * replaced "ops" section by extended "consts" section, which is capable of
  1662   handling the continuous function space "->" directly;
  1663 
  1664 * domain package:
  1665   . proves theorems immediately and stores them in the theory,
  1666   . creates hierachical name space,
  1667   . now uses normal mixfix annotations (instead of cinfix...),
  1668   . minor changes to some names and values (for consistency),
  1669   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1670   . separator between mutual domain defs: changed "," to "and",
  1671   . improved handling of sort constraints;  now they have to
  1672     appear on the left-hand side of the equations only;
  1673 
  1674 * fixed LAM <x,y,zs>.b syntax;
  1675 
  1676 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1677 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1678 
  1679 
  1680 *** FOL and ZF ***
  1681 
  1682 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1683   with `addloop' of the simplifier to faciliate case splitting in premises.
  1684 
  1685 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1686 in HOL, they strip ALL and --> from proved theorems;
  1687 
  1688 
  1689 
  1690 New in Isabelle94-8 (May 1997)
  1691 ------------------------------
  1692 
  1693 *** General Changes ***
  1694 
  1695 * new utilities to build / run / maintain Isabelle etc. (in parts
  1696 still somewhat experimental); old Makefiles etc. still functional;
  1697 
  1698 * new 'Isabelle System Manual';
  1699 
  1700 * INSTALL text, together with ./configure and ./build scripts;
  1701 
  1702 * reimplemented type inference for greater efficiency, better error
  1703 messages and clean internal interface;
  1704 
  1705 * prlim command for dealing with lots of subgoals (an easier way of
  1706 setting goals_limit);
  1707 
  1708 
  1709 *** Syntax ***
  1710 
  1711 * supports alternative (named) syntax tables (parser and pretty
  1712 printer); internal interface is provided by add_modesyntax(_i);
  1713 
  1714 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1715 be used in conjunction with the Isabelle symbol font; uses the
  1716 "symbols" syntax table;
  1717 
  1718 * added token_translation interface (may translate name tokens in
  1719 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1720 the current print_mode); IMPORTANT: user print translation functions
  1721 are responsible for marking newly introduced bounds
  1722 (Syntax.mark_boundT);
  1723 
  1724 * token translations for modes "xterm" and "xterm_color" that display
  1725 names in bold, underline etc. or colors (which requires a color
  1726 version of xterm);
  1727 
  1728 * infixes may now be declared with names independent of their syntax;
  1729 
  1730 * added typed_print_translation (like print_translation, but may
  1731 access type of constant);
  1732 
  1733 
  1734 *** Classical Reasoner ***
  1735 
  1736 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1737 some limitations.  Blast_tac...
  1738   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1739   + ignores elimination rules that don't have the correct format
  1740         (the conclusion MUST be a formula variable)
  1741   + ignores types, which can make HOL proofs fail
  1742   + rules must not require higher-order unification, e.g. apply_type in ZF
  1743     [message "Function Var's argument not a bound variable" relates to this]
  1744   + its proof strategy is more general but can actually be slower
  1745 
  1746 * substitution with equality assumptions no longer permutes other
  1747 assumptions;
  1748 
  1749 * minor changes in semantics of addafter (now called addaltern); renamed
  1750 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1751 (and access functions for it);
  1752 
  1753 * improved combination of classical reasoner and simplifier:
  1754   + functions for handling clasimpsets
  1755   + improvement of addss: now the simplifier is called _after_ the
  1756     safe steps.
  1757   + safe variant of addss called addSss: uses safe simplifications
  1758     _during_ the safe steps. It is more complete as it allows multiple
  1759     instantiations of unknowns (e.g. with slow_tac).
  1760 
  1761 *** Simplifier ***
  1762 
  1763 * added interface for simplification procedures (functions that
  1764 produce *proven* rewrite rules on the fly, depending on current
  1765 redex);
  1766 
  1767 * ordering on terms as parameter (used for ordered rewriting);
  1768 
  1769 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1770 
  1771 * the solver is now split into a safe and an unsafe part.
  1772 This should be invisible for the normal user, except that the
  1773 functions setsolver and addsolver have been renamed to setSolver and
  1774 addSolver; added safe_asm_full_simp_tac;
  1775 
  1776 
  1777 *** HOL ***
  1778 
  1779 * a generic induction tactic `induct_tac' which works for all datatypes and
  1780 also for type `nat';
  1781 
  1782 * a generic case distinction tactic `exhaust_tac' which works for all
  1783 datatypes and also for type `nat';
  1784 
  1785 * each datatype comes with a function `size';
  1786 
  1787 * patterns in case expressions allow tuple patterns as arguments to
  1788 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1789 
  1790 * primrec now also works with type nat;
  1791 
  1792 * recdef: a new declaration form, allows general recursive functions to be
  1793 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1794 
  1795 * the constant for negation has been renamed from "not" to "Not" to
  1796 harmonize with FOL, ZF, LK, etc.;
  1797 
  1798 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1799 infinite lists;
  1800 
  1801 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1802 
  1803 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1804 problems in commutative rings, using axiomatic type classes for + and *;
  1805 
  1806 * more examples in HOL/MiniML and HOL/Auth;
  1807 
  1808 * more default rewrite rules for quantifiers, union/intersection;
  1809 
  1810 * a new constant `arbitrary == @x.False';
  1811 
  1812 * HOLCF/IOA replaces old HOL/IOA;
  1813 
  1814 * HOLCF changes: derived all rules and arities
  1815   + axiomatic type classes instead of classes
  1816   + typedef instead of faking type definitions
  1817   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1818   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1819   + eliminated the types void, one, tr
  1820   + use unit lift and bool lift (with translations) instead of one and tr
  1821   + eliminated blift from Lift3.thy (use Def instead of blift)
  1822   all eliminated rules are derived as theorems --> no visible changes ;
  1823 
  1824 
  1825 *** ZF ***
  1826 
  1827 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1828 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1829 as ZF_cs addSIs [equalityI];
  1830 
  1831 
  1832 
  1833 New in Isabelle94-7 (November 96)
  1834 ---------------------------------
  1835 
  1836 * allowing negative levels (as offsets) in prlev and choplev;
  1837 
  1838 * super-linear speedup for large simplifications;
  1839 
  1840 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1841 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1842 FAIL); can suppress it using the command Delsimps (ex_simps @
  1843 all_simps); De Morgan laws are also now included, by default;
  1844 
  1845 * improved printing of ==>  :  ~:
  1846 
  1847 * new object-logic "Sequents" adds linear logic, while replacing LK
  1848 and Modal (thanks to Sara Kalvala);
  1849 
  1850 * HOL/Auth: correctness proofs for authentication protocols;
  1851 
  1852 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1853 examples on HOL/Auth);
  1854 
  1855 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1856 the rewriter and classical reasoner simultaneously;
  1857 
  1858 * function uresult no longer returns theorems in "standard" format;
  1859 regain previous version by: val uresult = standard o uresult;
  1860 
  1861 
  1862 
  1863 New in Isabelle94-6
  1864 -------------------
  1865 
  1866 * oracles -- these establish an interface between Isabelle and trusted
  1867 external reasoners, which may deliver results as theorems;
  1868 
  1869 * proof objects (in particular record all uses of oracles);
  1870 
  1871 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1872 
  1873 * "constdefs" section in theory files;
  1874 
  1875 * "primrec" section (HOL) no longer requires names;
  1876 
  1877 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1878 
  1879 
  1880 
  1881 New in Isabelle94-5
  1882 -------------------
  1883 
  1884 * reduced space requirements;
  1885 
  1886 * automatic HTML generation from theories;
  1887 
  1888 * theory files no longer require "..." (quotes) around most types;
  1889 
  1890 * new examples, including two proofs of the Church-Rosser theorem;
  1891 
  1892 * non-curried (1994) version of HOL is no longer distributed;
  1893 
  1894 
  1895 
  1896 New in Isabelle94-4
  1897 -------------------
  1898 
  1899 * greatly reduced space requirements;
  1900 
  1901 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1902 
  1903 * searchable theorem database (see the section "Retrieving theorems" on
  1904 page 8 of the Reference Manual);
  1905 
  1906 * new examples, including Grabczewski's monumental case study of the
  1907 Axiom of Choice;
  1908 
  1909 * The previous version of HOL renamed to Old_HOL;
  1910 
  1911 * The new version of HOL (previously called CHOL) uses a curried syntax
  1912 for functions.  Application looks like f a b instead of f(a,b);
  1913 
  1914 * Mutually recursive inductive definitions finally work in HOL;
  1915 
  1916 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1917 translates to the operator "split";
  1918 
  1919 
  1920 
  1921 New in Isabelle94-3
  1922 -------------------
  1923 
  1924 * new infix operator, addss, allowing the classical reasoner to
  1925 perform simplification at each step of its search.  Example:
  1926         fast_tac (cs addss ss)
  1927 
  1928 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1929 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1930 look like (a,b) instead of <a,b>;
  1931 
  1932 * PLEASE NOTE: CHOL will eventually replace HOL!
  1933 
  1934 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1935 It translates to the operator "split".  A new theory of integers is available;
  1936 
  1937 * In ZF, integer numerals now denote two's-complement binary integers.
  1938 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1939 
  1940 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1941 of the Axiom of Choice;
  1942 
  1943 
  1944 
  1945 New in Isabelle94-2
  1946 -------------------
  1947 
  1948 * Significantly faster resolution;
  1949 
  1950 * the different sections in a .thy file can now be mixed and repeated
  1951 freely;
  1952 
  1953 * Database of theorems for FOL, HOL and ZF.  New
  1954 commands including qed, qed_goal and bind_thm store theorems in the database.
  1955 
  1956 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1957 a given theory (thms_of), or find out what theory a theorem was proved in
  1958 (theory_of_thm);
  1959 
  1960 * Bugs fixed in the inductive definition and datatype packages;
  1961 
  1962 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1963 and HOL_dup_cs obsolete;
  1964 
  1965 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1966 have been removed;
  1967 
  1968 * Simpler definition of function space in ZF;
  1969 
  1970 * new results about cardinal and ordinal arithmetic in ZF;
  1971 
  1972 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1973 types;
  1974 
  1975 
  1976 $Id$