NEWS
author wenzelm
Thu Oct 25 02:13:02 2001 +0200 (2001-10-25)
changeset 11930 1accec985349
parent 11921 2a0e9622dc51
child 11933 acfea249b03c
permissions -rw-r--r--
* HOL/record:
- provides cases/induct rules for use with corresponding Isar methods;
- "record" operation truncates to particular fixed record (acts like
a type cast);
- make_defs no longer part of default simps;
- internal definitions directly based on a light-weight abstract
theory of product types over typedef rather than datatype;
     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/record:
   101   - provides cases/induct rules for use with corresponding Isar methods;
   102   - "record" operation truncates to particular fixed record (acts like
   103     a type cast);
   104   - make_defs no longer part of default simps;
   105   - internal definitions directly based on a light-weight abstract
   106     theory of product types over typedef rather than datatype;
   107 
   108 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   109 (beware of argument permutation!);
   110 
   111 * HOL: linorder_less_split superseded by linorder_cases;
   112 
   113 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   114 to peripheral theory "Hilbert_Choice";
   115 
   116 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   117 in this (rare) case use:
   118 
   119   delSWrapper "split_all_tac"
   120   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   121 
   122 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   123 MAY FAIL;
   124 
   125 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   126 Isabelle's type classes, ^ on functions and relations has too general
   127 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   128 necessary to attach explicit type constraints;
   129 
   130 * HOL: syntax translations now work properly with numerals and records
   131 expressions;
   132 
   133 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   134 Florian Kammüller;
   135 
   136 * HOL: eliminated global items
   137 
   138   const "()" -> "Product_Type.Unity"
   139   type "unit" -> "Product_Type.unit"
   140 
   141 
   142 *** ZF ***
   143 
   144 * ZF: the integer library now covers quotients and remainders, with
   145 many laws relating division to addition, multiplication, etc.;
   146 
   147 
   148 *** General ***
   149 
   150 * kernel: meta-level proof terms (by Stefan Berghofer), see also ref
   151 manual;
   152 
   153 * classical: renamed addaltern to addafter, addSaltern to addSafter;
   154 
   155 * clasimp: ``iff'' declarations now handle conditional rules as well;
   156 
   157 * syntax: new token syntax "num" for plain numerals (without "#" of
   158 "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now separate
   159 tokens, so expressions involving minus need to be spaced properly;
   160 
   161 * syntax: support non-oriented infixes;
   162 
   163 * syntax: print modes "type_brackets" and "no_type_brackets" control
   164 output of nested => (types); the default behavior is "type_brackets";
   165 
   166 * syntax: builtin parse translation for "_constify" turns valued
   167 tokens into AST constants;
   168 
   169 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   170 
   171 * system: Proof General keywords specification is now part of the
   172 Isabelle distribution (see etc/isar-keywords.el);
   173 
   174 * system: smart selection of Isabelle process versus Isabelle
   175 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   176 run both "isabelle" and "Isabelle" even if file names are badly
   177 damaged (executable inspects the case of the first letter of its own
   178 name); added separate "isabelle-process" and "isabelle-interface";
   179 
   180 
   181 
   182 New in Isabelle99-2 (February 2001)
   183 -----------------------------------
   184 
   185 *** Overview of INCOMPATIBILITIES ***
   186 
   187 * HOL: please note that theories in the Library and elsewhere often use the
   188 new-style (Isar) format; to refer to their theorems in an ML script you must
   189 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   190 
   191 * HOL: inductive package no longer splits induction rule aggressively,
   192 but only as far as specified by the introductions given; the old
   193 format may be recovered via ML function complete_split_rule or attribute
   194 'split_rule (complete)';
   195 
   196 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   197 gfp_Tarski to gfp_unfold;
   198 
   199 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   200 
   201 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   202 relation); infix "^^" has been renamed "``"; infix "``" has been
   203 renamed "`"; "univalent" has been renamed "single_valued";
   204 
   205 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   206 operation;
   207 
   208 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   209 
   210 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   211 
   212 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   213 consequence, it is no longer monotonic wrt. the local goal context
   214 (which is now passed through the inductive cases);
   215 
   216 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   217 \<gg> to \<ggreater>;
   218 
   219 
   220 *** Document preparation ***
   221 
   222 * \isabellestyle{NAME} selects version of Isabelle output (currently
   223 available: are "it" for near math-mode best-style output, "sl" for
   224 slanted text style, and "tt" for plain type-writer; if no
   225 \isabellestyle command is given, output is according to slanted
   226 type-writer);
   227 
   228 * support sub/super scripts (for single symbols only), input syntax is
   229 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   230 
   231 * some more standard symbols; see Appendix A of the system manual for
   232 the complete list of symbols defined in isabellesym.sty;
   233 
   234 * improved isabelle style files; more abstract symbol implementation
   235 (should now use \isamath{...} and \isatext{...} in custom symbol
   236 definitions);
   237 
   238 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   239 state; Note that presentation of goal states does not conform to
   240 actual human-readable proof documents.  Please do not include goal
   241 states into document output unless you really know what you are doing!
   242 
   243 * proper indentation of antiquoted output with proportional LaTeX
   244 fonts;
   245 
   246 * no_document ML operator temporarily disables LaTeX document
   247 generation;
   248 
   249 * isatool unsymbolize tunes sources for plain ASCII communication;
   250 
   251 
   252 *** Isar ***
   253 
   254 * Pure: Isar now suffers initial goal statements to contain unbound
   255 schematic variables (this does not conform to actual readable proof
   256 documents, due to unpredictable outcome and non-compositional proof
   257 checking); users who know what they are doing may use schematic goals
   258 for Prolog-style synthesis of proven results;
   259 
   260 * Pure: assumption method (an implicit finishing) now handles actual
   261 rules as well;
   262 
   263 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   264 initial goal, declare "that" only as Pure intro (only for single
   265 steps); the "that" rule assumption may now be involved in implicit
   266 finishing, thus ".." becomes a feasible for trivial obtains;
   267 
   268 * Pure: default proof step now includes 'intro_classes'; thus trivial
   269 instance proofs may be performed by "..";
   270 
   271 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   272 statements as well;
   273 
   274 * Pure: more robust selection of calculational rules;
   275 
   276 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   277 rule (as well as the assumption rule);
   278 
   279 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   280 lemmas, using the graph browser tool;
   281 
   282 * Pure: predict failure of "show" in interactive mode;
   283 
   284 * Pure: 'thms_containing' now takes actual terms as arguments;
   285 
   286 * HOL: improved method 'induct' --- now handles non-atomic goals
   287 (potential INCOMPATIBILITY); tuned error handling;
   288 
   289 * HOL: cases and induct rules now provide explicit hints about the
   290 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   291 any remaining facts are inserted into the goal verbatim;
   292 
   293 * HOL: local contexts (aka cases) may now contain term bindings as
   294 well; the 'cases' and 'induct' methods new provide a ?case binding for
   295 the result to be shown in each case;
   296 
   297 * HOL: added 'recdef_tc' command;
   298 
   299 * isatool convert assists in eliminating legacy ML scripts;
   300 
   301 
   302 *** HOL ***
   303 
   304 * HOL/Library: a collection of generic theories to be used together
   305 with main HOL; the theory loader path already includes this directory
   306 by default; the following existing theories have been moved here:
   307 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   308 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   309 
   310 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   311 modelling and verification task performed in Isabelle/HOL +
   312 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   313 
   314 * HOL/Algebra: special summation operator SUM no longer exists, it has
   315 been replaced by setsum; infix 'assoc' now has priority 50 (like
   316 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   317 'domain', this makes the theory consistent with mathematical
   318 literature;
   319 
   320 * HOL basics: added overloaded operations "inverse" and "divide"
   321 (infix "/"), syntax for generic "abs" operation, generic summation
   322 operator \<Sum>;
   323 
   324 * HOL/typedef: simplified package, provide more useful rules (see also
   325 HOL/subset.thy);
   326 
   327 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   328 now expressed as a proper nested rule (old-style tactic scripts may
   329 require atomize_strip_tac to cope with non-atomic premises);
   330 
   331 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   332 to "split_conv" (old name still available for compatibility);
   333 
   334 * HOL: improved concrete syntax for strings (e.g. allows translation
   335 rules with string literals);
   336 
   337 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   338 and Fleuriot's mechanization of analysis;
   339 
   340 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   341 
   342 
   343 *** CTT ***
   344 
   345 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   346 "lam" is displayed as TWO lambda-symbols
   347 
   348 * CTT: theory Main now available, containing everything (that is, Bool
   349 and Arith);
   350 
   351 
   352 *** General ***
   353 
   354 * Pure: the Simplifier has been implemented properly as a derived rule
   355 outside of the actual kernel (at last!); the overall performance
   356 penalty in practical applications is about 50%, while reliability of
   357 the Isabelle inference kernel has been greatly improved;
   358 
   359 * print modes "brackets" and "no_brackets" control output of nested =>
   360 (types) and ==> (props); the default behaviour is "brackets";
   361 
   362 * Provers: fast_tac (and friends) now handle actual object-logic rules
   363 as assumptions as well;
   364 
   365 * system: support Poly/ML 4.0;
   366 
   367 * system: isatool install handles KDE version 1 or 2;
   368 
   369 
   370 
   371 New in Isabelle99-1 (October 2000)
   372 ----------------------------------
   373 
   374 *** Overview of INCOMPATIBILITIES ***
   375 
   376 * HOL: simplification of natural numbers is much changed; to partly
   377 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   378 issue the following ML commands:
   379 
   380   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   381   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   382 
   383 * HOL: simplification no longer dives into case-expressions; this is
   384 controlled by "t.weak_case_cong" for each datatype t;
   385 
   386 * HOL: nat_less_induct renamed to less_induct;
   387 
   388 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   389 fixsome to patch .thy and .ML sources automatically;
   390 
   391   select_equality  -> some_equality
   392   select_eq_Ex     -> some_eq_ex
   393   selectI2EX       -> someI2_ex
   394   selectI2         -> someI2
   395   selectI          -> someI
   396   select1_equality -> some1_equality
   397   Eps_sym_eq       -> some_sym_eq_trivial
   398   Eps_eq           -> some_eq_trivial
   399 
   400 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   401 
   402 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   403 instead);
   404 
   405 * HOL: the recursion equations generated by 'recdef' are now called
   406 f.simps instead of f.rules;
   407 
   408 * HOL: qed_spec_mp now also handles bounded ALL as well;
   409 
   410 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   411 sometimes be needed;
   412 
   413 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   414 
   415 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   416 
   417 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   418 product is now "<*>" instead of "Times"; the lexicographic product is
   419 now "<*lex*>" instead of "**";
   420 
   421 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   422 of main HOL, but was unused); better use HOL's datatype package;
   423 
   424 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   425 the old syntax may be recovered as follows:
   426 
   427   syntax (symbols)
   428     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   429       (infixl "\\<oplus>" 100)
   430 
   431 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   432 
   433 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   434 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   435 internally;
   436 
   437 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   438 changed from A/r to A//r;
   439 
   440 * ZF: new treatment of arithmetic (nat & int) may break some old
   441 proofs;
   442 
   443 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   444 rulify -> rule_format, elimify -> elim_format, ...);
   445 
   446 * Isar/Provers: intro/elim/dest attributes changed; renamed
   447 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   448 should have to change intro!! to intro? only); replaced "delrule" by
   449 "rule del";
   450 
   451 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   452 
   453 * Provers: strengthened force_tac by using new first_best_tac;
   454 
   455 * LaTeX document preparation: several changes of isabelle.sty (see
   456 lib/texinputs);
   457 
   458 
   459 *** Document preparation ***
   460 
   461 * formal comments (text blocks etc.) in new-style theories may now
   462 contain antiquotations of thm/prop/term/typ/text to be presented
   463 according to latex print mode; concrete syntax is like this:
   464 @{term[show_types] "f(x) = a + x"};
   465 
   466 * isatool mkdir provides easy setup of Isabelle session directories,
   467 including proper document sources;
   468 
   469 * generated LaTeX sources are now deleted after successful run
   470 (isatool document -c); may retain a copy somewhere else via -D option
   471 of isatool usedir;
   472 
   473 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   474 style files, achieving self-contained LaTeX sources and simplifying
   475 LaTeX debugging;
   476 
   477 * old-style theories now produce (crude) LaTeX output as well;
   478 
   479 * browser info session directories are now self-contained (may be put
   480 on WWW server seperately); improved graphs of nested sessions; removed
   481 graph for 'all sessions';
   482 
   483 * several improvements in isabelle style files; \isabellestyle{it}
   484 produces fake math mode output; \isamarkupheader is now \section by
   485 default; see lib/texinputs/isabelle.sty etc.;
   486 
   487 
   488 *** Isar ***
   489 
   490 * Isar/Pure: local results and corresponding term bindings are now
   491 subject to Hindley-Milner polymorphism (similar to ML); this
   492 accommodates incremental type-inference very nicely;
   493 
   494 * Isar/Pure: new derived language element 'obtain' supports
   495 generalized existence reasoning;
   496 
   497 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   498 support accumulation of results, without applying any rules yet;
   499 useful to collect intermediate results without explicit name
   500 references, and for use with transitivity rules with more than 2
   501 premises;
   502 
   503 * Isar/Pure: scalable support for case-analysis type proofs: new
   504 'case' language element refers to local contexts symbolically, as
   505 produced by certain proof methods; internally, case names are attached
   506 to theorems as "tags";
   507 
   508 * Isar/Pure: theory command 'hide' removes declarations from
   509 class/type/const name spaces;
   510 
   511 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   512 indicate potential overloading;
   513 
   514 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   515 
   516 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   517 "{a,b,c}" instead of {a,b,c};
   518 
   519 * Isar/Pure now provides its own version of intro/elim/dest
   520 attributes; useful for building new logics, but beware of confusion
   521 with the version in Provers/classical;
   522 
   523 * Isar/Pure: the local context of (non-atomic) goals is provided via
   524 case name 'antecedent';
   525 
   526 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   527 to the current context is now done automatically);
   528 
   529 * Isar/Pure: theory command 'method_setup' provides a simple interface
   530 for definining proof methods in ML;
   531 
   532 * Isar/Provers: intro/elim/dest attributes changed; renamed
   533 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   534 most cases, one should have to change intro!! to intro? only);
   535 replaced "delrule" by "rule del";
   536 
   537 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   538 'symmetric' attribute (the latter supercedes [RS sym]);
   539 
   540 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   541 method modifier); 'simp' method: 'only:' modifier removes loopers as
   542 well (including splits);
   543 
   544 * Isar/Provers: Simplifier and Classical methods now support all kind
   545 of modifiers used in the past, including 'cong', 'iff', etc.
   546 
   547 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   548 of Simplifier and Classical reasoner);
   549 
   550 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   551 now support named cases; major packages (inductive, datatype, primrec,
   552 recdef) support case names and properly name parameters;
   553 
   554 * Isar/HOL: new transitivity rules for substitution in inequalities --
   555 monotonicity conditions are extracted to be proven at end of
   556 calculations;
   557 
   558 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   559 method anyway;
   560 
   561 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   562 split_if split_if_asm; datatype package provides theorems foo.splits =
   563 foo.split foo.split_asm for each datatype;
   564 
   565 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   566 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   567 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   568 use "(cases (simplified))" method in proper proof texts);
   569 
   570 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   571 
   572 * Isar: names of theorems etc. may be natural numbers as well;
   573 
   574 * Isar: 'pr' command: optional arguments for goals_limit and
   575 ProofContext.prems_limit; no longer prints theory contexts, but only
   576 proof states;
   577 
   578 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   579 additional print modes to be specified; e.g. "pr(latex)" will print
   580 proof state according to the Isabelle LaTeX style;
   581 
   582 * Isar: improved support for emulating tactic scripts, including proof
   583 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   584 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   585 (for HOL datatypes);
   586 
   587 * Isar: simplified (more robust) goal selection of proof methods: 1st
   588 goal, all goals, or explicit goal specifier (tactic emulation); thus
   589 'proof method scripts' have to be in depth-first order;
   590 
   591 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   592 
   593 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   594 should instead use individual commands for printing items
   595 (print_commands, print_methods etc.);
   596 
   597 * Isar: added 'nothing' --- the empty list of theorems;
   598 
   599 
   600 *** HOL ***
   601 
   602 * HOL/MicroJava: formalization of a fragment of Java, together with a
   603 corresponding virtual machine and a specification of its bytecode
   604 verifier and a lightweight bytecode verifier, including proofs of
   605 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   606 Cornelia Pusch (see also the homepage of project Bali at
   607 http://isabelle.in.tum.de/Bali/);
   608 
   609 * HOL/Algebra: new theory of rings and univariate polynomials, by
   610 Clemens Ballarin;
   611 
   612 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   613 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   614 Rasmussen;
   615 
   616 * HOL/Lattice: fundamental concepts of lattice theory and order
   617 structures, including duals, properties of bounds versus algebraic
   618 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   619 Theorem for complete lattices etc.; may also serve as a demonstration
   620 for abstract algebraic reasoning using axiomatic type classes, and
   621 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   622 
   623 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   624 von Oheimb;
   625 
   626 * HOL/IMPP: extension of IMP with local variables and mutually
   627 recursive procedures, by David von Oheimb;
   628 
   629 * HOL/Lambda: converted into new-style theory and document;
   630 
   631 * HOL/ex/Multiquote: example of multiple nested quotations and
   632 anti-quotations -- basically a generalized version of de-Bruijn
   633 representation; very useful in avoiding lifting of operations;
   634 
   635 * HOL/record: added general record equality rule to simpset; fixed
   636 select-update simplification procedure to handle extended records as
   637 well; admit "r" as field name;
   638 
   639 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   640 other numeric types and also as the identity of groups, rings, etc.;
   641 
   642 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   643 Types nat and int belong to this axclass;
   644 
   645 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   646    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   647    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   648   two terms #m*u and #n*u are replaced by #(m+n)*u
   649     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   650   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   651     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   652 
   653 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   654 powerful prover for predicate logic but knows nothing of clasets; see
   655 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   656 
   657 * HOL: new version of "case_tac" subsumes both boolean case split and
   658 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   659 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   660 
   661 * HOL: simplification no longer dives into case-expressions: only the
   662 selector expression is simplified, but not the remaining arms; to
   663 enable full simplification of case-expressions for datatype t, you may
   664 remove t.weak_case_cong from the simpset, either globally (Delcongs
   665 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   666 
   667 * HOL/recdef: the recursion equations generated by 'recdef' for
   668 function 'f' are now called f.simps instead of f.rules; if all
   669 termination conditions are proved automatically, these simplification
   670 rules are added to the simpset, as in primrec; rules may be named
   671 individually as well, resulting in a separate list of theorems for
   672 each equation;
   673 
   674 * HOL/While is a new theory that provides a while-combinator. It
   675 permits the definition of tail-recursive functions without the
   676 provision of a termination measure. The latter is necessary once the
   677 invariant proof rule for while is applied.
   678 
   679 * HOL: new (overloaded) notation for the set of elements below/above
   680 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   681 
   682 * HOL: theorems impI, allI, ballI bound as "strip";
   683 
   684 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   685 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   686 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   687 
   688 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   689 
   690 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   691 main HOL, but was unused);
   692 
   693 * HOL: fewer consts declared as global (e.g. have to refer to
   694 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   695 
   696 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   697 in case of overlap with user translations (e.g. judgements over
   698 tuples); (note that the underlying logical represenation is still
   699 bogus);
   700 
   701 
   702 *** ZF ***
   703 
   704 * ZF: simplification automatically cancels common terms in arithmetic
   705 expressions over nat and int;
   706 
   707 * ZF: new treatment of nat to minimize type-checking: all operators
   708 coerce their operands to a natural number using the function natify,
   709 making the algebraic laws unconditional;
   710 
   711 * ZF: as above, for int: operators coerce their operands to an integer
   712 using the function intify;
   713 
   714 * ZF: the integer library now contains many of the usual laws for the
   715 orderings, including $<=, and monotonicity laws for $+ and $*;
   716 
   717 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   718 simplification;
   719 
   720 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   721 to the simplifier and classical reasoner simultaneously;
   722 
   723 
   724 *** General ***
   725 
   726 * Provers: blast_tac now handles actual object-logic rules as
   727 assumptions; note that auto_tac uses blast_tac internally as well;
   728 
   729 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   730 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   731 
   732 * Provers: delrules now handles destruct rules as well (no longer need
   733 explicit make_elim);
   734 
   735 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   736   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   737 use instead the strong form,
   738   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   739 in HOL, FOL and ZF the function cla_make_elim will create such rules
   740 from destruct-rules;
   741 
   742 * Provers: Simplifier.easy_setup provides a fast path to basic
   743 Simplifier setup for new object-logics;
   744 
   745 * Pure: AST translation rules no longer require constant head on LHS;
   746 
   747 * Pure: improved name spaces: ambiguous output is qualified; support
   748 for hiding of names;
   749 
   750 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   751 XSYMBOL_HOME; no longer need to do manual configuration in most
   752 situations;
   753 
   754 * system: compression of ML heaps images may now be controlled via -c
   755 option of isabelle and isatool usedir (currently only observed by
   756 Poly/ML);
   757 
   758 * system: isatool installfonts may handle X-Symbol fonts as well (very
   759 useful for remote X11);
   760 
   761 * system: provide TAGS file for Isabelle sources;
   762 
   763 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   764 order;
   765 
   766 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   767 timing flag supersedes proof_timing and Toplevel.trace;
   768 
   769 * ML: new combinators |>> and |>>> for incremental transformations
   770 with secondary results (e.g. certain theory extensions):
   771 
   772 * ML: PureThy.add_defs gets additional argument to indicate potential
   773 overloading (usually false);
   774 
   775 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   776 results;
   777 
   778 
   779 
   780 New in Isabelle99 (October 1999)
   781 --------------------------------
   782 
   783 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   784 
   785 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   786 are no longer simplified.  (This allows the simplifier to unfold recursive
   787 functional programs.)  To restore the old behaviour, declare
   788 
   789     Delcongs [if_weak_cong];
   790 
   791 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   792 complement;
   793 
   794 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   795 
   796 * HOL/datatype: mutual_induct_tac no longer exists --
   797   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   798 
   799 * HOL/typedef: fixed type inference for representing set; type
   800 arguments now have to occur explicitly on the rhs as type constraints;
   801 
   802 * ZF: The con_defs part of an inductive definition may no longer refer
   803 to constants declared in the same theory;
   804 
   805 * HOL, ZF: the function mk_cases, generated by the inductive
   806 definition package, has lost an argument.  To simplify its result, it
   807 uses the default simpset instead of a supplied list of theorems.
   808 
   809 * HOL/List: the constructors of type list are now Nil and Cons;
   810 
   811 * Simplifier: the type of the infix ML functions
   812         setSSolver addSSolver setSolver addSolver
   813 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   814 for packaging solvers. A solver is created via
   815         mk_solver: string -> (thm list -> int -> tactic) -> solver
   816 where the string argument is only a comment.
   817 
   818 
   819 *** Proof tools ***
   820 
   821 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   822 decision procedure for linear arithmetic. Currently it is used for
   823 types `nat', `int', and `real' in HOL (see below); it can, should and
   824 will be instantiated for other types and logics as well.
   825 
   826 * The simplifier now accepts rewrite rules with flexible heads, eg
   827      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   828   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   829   matching.
   830 
   831 
   832 *** General ***
   833 
   834 * New Isabelle/Isar subsystem provides an alternative to traditional
   835 tactical theorem proving; together with the ProofGeneral/isar user
   836 interface it offers an interactive environment for developing human
   837 readable proof documents (Isar == Intelligible semi-automated
   838 reasoning); for further information see isatool doc isar-ref,
   839 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   840 
   841 * improved and simplified presentation of theories: better HTML markup
   842 (including colors), graph views in several sizes; isatool usedir now
   843 provides a proper interface for user theories (via -P option); actual
   844 document preparation based on (PDF)LaTeX is available as well (for
   845 new-style theories only); see isatool doc system for more information;
   846 
   847 * native support for Proof General, both for classic Isabelle and
   848 Isabelle/Isar;
   849 
   850 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   851 using the graph browser tool;
   852 
   853 * Isabelle manuals now also available as PDF;
   854 
   855 * theory loader rewritten from scratch (may not be fully
   856 bug-compatible); old loadpath variable has been replaced by show_path,
   857 add_path, del_path, reset_path functions; new operations such as
   858 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   859 isatool doc ref);
   860 
   861 * improved isatool install: option -k creates KDE application icon,
   862 option -p DIR installs standalone binaries;
   863 
   864 * added ML_PLATFORM setting (useful for cross-platform installations);
   865 more robust handling of platform specific ML images for SML/NJ;
   866 
   867 * the settings environment is now statically scoped, i.e. it is never
   868 created again in sub-processes invoked from isabelle, isatool, or
   869 Isabelle;
   870 
   871 * path element specification '~~' refers to '$ISABELLE_HOME';
   872 
   873 * in locales, the "assumes" and "defines" parts may be omitted if
   874 empty;
   875 
   876 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   877 long arrows);
   878 
   879 * new print_mode "HTML";
   880 
   881 * new flag show_tags controls display of tags of theorems (which are
   882 basically just comments that may be attached by some tools);
   883 
   884 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   885 mode and goal output format:
   886 
   887 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   888 244c244
   889 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   890 ---
   891 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   892 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   893 181c181
   894 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   895 ---
   896 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   897 
   898 * function bind_thms stores lists of theorems (cf. bind_thm);
   899 
   900 * new shorthand tactics ftac, eatac, datac, fatac;
   901 
   902 * qed (and friends) now accept "" as result name; in that case the
   903 theorem is not stored, but proper checks and presentation of the
   904 result still apply;
   905 
   906 * theorem database now also indexes constants "Trueprop", "all",
   907 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   908 
   909 
   910 *** HOL ***
   911 
   912 ** HOL arithmetic **
   913 
   914 * There are now decision procedures for linear arithmetic over nat and
   915 int:
   916 
   917 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   918 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   919 are treated as atomic; subformulae not involving type `nat' or `int'
   920 are ignored; quantified subformulae are ignored unless they are
   921 positive universal or negative existential. The tactic has to be
   922 invoked by hand and can be a little bit slow. In particular, the
   923 running time is exponential in the number of occurrences of `min' and
   924 `max', and `-' on `nat'.
   925 
   926 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   927 (negated) (in)equalities among the premises and the conclusion into
   928 account (i.e. no compound formulae) and does not know about `min' and
   929 `max', and `-' on `nat'. It is fast and is used automatically by the
   930 simplifier.
   931 
   932 NB: At the moment, these decision procedures do not cope with mixed
   933 nat/int formulae where the two parts interact, such as `m < n ==>
   934 int(m) < int(n)'.
   935 
   936 * HOL/Numeral provides a generic theory of numerals (encoded
   937 efficiently as bit strings); setup for types nat/int/real is in place;
   938 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   939 int, existing theories and proof scripts may require a few additional
   940 type constraints;
   941 
   942 * integer division and remainder can now be performed on constant
   943 arguments;
   944 
   945 * many properties of integer multiplication, division and remainder
   946 are now available;
   947 
   948 * An interface to the Stanford Validity Checker (SVC) is available through the
   949 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   950 are proved automatically.  SVC must be installed separately, and its results
   951 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   952 invocation of the underlying oracle).  For SVC see
   953   http://verify.stanford.edu/SVC
   954 
   955 * IsaMakefile: the HOL-Real target now builds an actual image;
   956 
   957 
   958 ** HOL misc **
   959 
   960 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   961 (in Isabelle/Isar) -- by Gertrud Bauer;
   962 
   963 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   964 analysis for assembly languages with subtypes;
   965 
   966 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   967 -- avoids syntactic ambiguities and treats state, transition, and
   968 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   969 changed syntax and (many) tactics;
   970 
   971 * HOL/inductive: Now also handles more general introduction rules such
   972   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   973   theorems are now maintained within the theory (maintained via the
   974   "mono" attribute);
   975 
   976 * HOL/datatype: Now also handles arbitrarily branching datatypes
   977   (using function types) such as
   978 
   979   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   980 
   981 * HOL/record: record_simproc (part of the default simpset) takes care
   982 of selectors applied to updated records; record_split_tac is no longer
   983 part of the default claset; update_defs may now be removed from the
   984 simpset in many cases; COMPATIBILITY: old behavior achieved by
   985 
   986   claset_ref () := claset() addSWrapper record_split_wrapper;
   987   Delsimprocs [record_simproc]
   988 
   989 * HOL/typedef: fixed type inference for representing set; type
   990 arguments now have to occur explicitly on the rhs as type constraints;
   991 
   992 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   993 names rather than an ML expression;
   994 
   995 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   996 supplied later.  Program schemes can be defined, such as
   997     "While B C s = (if B s then While B C (C s) else s)"
   998 where the well-founded relation can be chosen after B and C have been given.
   999 
  1000 * HOL/List: the constructors of type list are now Nil and Cons;
  1001 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1002 course, ML tools referring to List.list.op # etc. have to be adapted;
  1003 
  1004 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1005 disabled by default; run isabelle with option -m HOL to get back to
  1006 the original Gordon/HOL-style output;
  1007 
  1008 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1009 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1010 
  1011 * HOL basic syntax simplified (more orthogonal): all variants of
  1012 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1013 Eps operator is provided as well: "SOME x. P[x]";
  1014 
  1015 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1016 
  1017 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1018 thus available for user theories;
  1019 
  1020 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1021 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1022 time;
  1023 
  1024 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1025 several times and then mp;
  1026 
  1027 
  1028 *** LK ***
  1029 
  1030 * the notation <<...>> is now available as a notation for sequences of
  1031 formulas;
  1032 
  1033 * the simplifier is now installed
  1034 
  1035 * the axiom system has been generalized (thanks to Soren Heilmann)
  1036 
  1037 * the classical reasoner now has a default rule database
  1038 
  1039 
  1040 *** ZF ***
  1041 
  1042 * new primrec section allows primitive recursive functions to be given
  1043 directly (as in HOL) over datatypes and the natural numbers;
  1044 
  1045 * new tactics induct_tac and exhaust_tac for induction (or case
  1046 analysis) over datatypes and the natural numbers;
  1047 
  1048 * the datatype declaration of type T now defines the recursor T_rec;
  1049 
  1050 * simplification automatically does freeness reasoning for datatype
  1051 constructors;
  1052 
  1053 * automatic type-inference, with AddTCs command to insert new
  1054 type-checking rules;
  1055 
  1056 * datatype introduction rules are now added as Safe Introduction rules
  1057 to the claset;
  1058 
  1059 * the syntax "if P then x else y" is now available in addition to
  1060 if(P,x,y);
  1061 
  1062 
  1063 *** Internal programming interfaces ***
  1064 
  1065 * tuned simplifier trace output; new flag debug_simp;
  1066 
  1067 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1068 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1069 
  1070 * AxClass.axclass_tac lost the theory argument;
  1071 
  1072 * tuned current_goals_markers semantics: begin / end goal avoids
  1073 printing empty lines;
  1074 
  1075 * removed prs and prs_fn hook, which was broken because it did not
  1076 include \n in its semantics, forcing writeln to add one
  1077 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1078 string -> unit if you really want to output text without newline;
  1079 
  1080 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1081 plain output, interface builders may have to enable 'isabelle_font'
  1082 mode to get Isabelle font glyphs as before;
  1083 
  1084 * refined token_translation interface; INCOMPATIBILITY: output length
  1085 now of type real instead of int;
  1086 
  1087 * theory loader actions may be traced via new ThyInfo.add_hook
  1088 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1089 your own database of information attached to *whole* theories -- as
  1090 opposed to intra-theory data slots offered via TheoryDataFun;
  1091 
  1092 * proper handling of dangling sort hypotheses (at last!);
  1093 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1094 extra sort hypotheses that can be witnessed from the type signature;
  1095 the force_strip_shyps flag is gone, any remaining shyps are simply
  1096 left in the theorem (with a warning issued by strip_shyps_warning);
  1097 
  1098 
  1099 
  1100 New in Isabelle98-1 (October 1998)
  1101 ----------------------------------
  1102 
  1103 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1104 
  1105 * several changes of automated proof tools;
  1106 
  1107 * HOL: major changes to the inductive and datatype packages, including
  1108 some minor incompatibilities of theory syntax;
  1109 
  1110 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1111 called `inj_on';
  1112 
  1113 * HOL: removed duplicate thms in Arith:
  1114   less_imp_add_less  should be replaced by  trans_less_add1
  1115   le_imp_add_le      should be replaced by  trans_le_add1
  1116 
  1117 * HOL: unary minus is now overloaded (new type constraints may be
  1118 required);
  1119 
  1120 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1121 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1122 now taken as an integer constant.
  1123 
  1124 * Pure: ML function 'theory_of' renamed to 'theory';
  1125 
  1126 
  1127 *** Proof tools ***
  1128 
  1129 * Simplifier:
  1130   1. Asm_full_simp_tac is now more aggressive.
  1131      1. It will sometimes reorient premises if that increases their power to
  1132         simplify.
  1133      2. It does no longer proceed strictly from left to right but may also
  1134         rotate premises to achieve further simplification.
  1135      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1136      old Asm_full_simp_tac in that it does not rotate premises.
  1137   2. The simplifier now knows a little bit about nat-arithmetic.
  1138 
  1139 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1140 allows for selected deletion of wrappers, by introduction of names for
  1141 wrapper functionals.  This implies that addbefore, addSbefore,
  1142 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1143 and that adding two tactics with the same name overwrites the first
  1144 one (emitting a warning).
  1145   type wrapper = (int -> tactic) -> (int -> tactic)
  1146   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1147   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1148   delWrapper, delSWrapper: claset *  string            -> claset
  1149   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1150 
  1151 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1152 semantics; addbefore now affects only the unsafe part of step_tac
  1153 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1154 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1155 by Force_tac;
  1156 
  1157 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1158 compWrapper; added safe wrapper (and access functions for it);
  1159 
  1160 * HOL/split_all_tac is now much faster and fails if there is nothing
  1161 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1162 and the names of the automatically generated variables have changed.
  1163 split_all_tac has moved within claset() from unsafe wrappers to safe
  1164 wrappers, which means that !!-bound variables are split much more
  1165 aggressively, and safe_tac and clarify_tac now split such variables.
  1166 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1167 Note: the same holds for record_split_tac, which does the job of
  1168 split_all_tac for record fields.
  1169 
  1170 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1171 permanently to the default simpset using Addsplits just like
  1172 Addsimps. They can be removed via Delsplits just like
  1173 Delsimps. Lower-case versions are also available.
  1174 
  1175 * HOL/Simplifier: The rule split_if is now part of the default
  1176 simpset. This means that the simplifier will eliminate all occurrences
  1177 of if-then-else in the conclusion of a goal. To prevent this, you can
  1178 either remove split_if completely from the default simpset by
  1179 `Delsplits [split_if]' or remove it in a specific call of the
  1180 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1181 other case splitting rules to/from the default simpset: every datatype
  1182 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1183 t is the name of the datatype).
  1184 
  1185 * Classical reasoner / Simplifier combination: new force_tac (and
  1186 derivatives Force_tac, force) combines rewriting and classical
  1187 reasoning (and whatever other tools) similarly to auto_tac, but is
  1188 aimed to solve the given subgoal completely.
  1189 
  1190 
  1191 *** General ***
  1192 
  1193 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1194 and `goalw': the theory is no longer needed as an explicit argument -
  1195 the current theory context is used; assumptions are no longer returned
  1196 at the ML-level unless one of them starts with ==> or !!; it is
  1197 recommended to convert to these new commands using isatool fixgoal
  1198 (backup your sources first!);
  1199 
  1200 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1201 the current theory context, and 'theory' to lookup stored theories;
  1202 
  1203 * new theory section 'locale' for declaring constants, assumptions and
  1204 definitions that have local scope;
  1205 
  1206 * new theory section 'nonterminals' for purely syntactic types;
  1207 
  1208 * new theory section 'setup' for generic ML setup functions
  1209 (e.g. package initialization);
  1210 
  1211 * the distribution now includes Isabelle icons: see
  1212 lib/logo/isabelle-{small,tiny}.xpm;
  1213 
  1214 * isatool install - install binaries with absolute references to
  1215 ISABELLE_HOME/bin;
  1216 
  1217 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1218 
  1219 * print mode 'emacs' reserved for Isamode;
  1220 
  1221 * support multiple print (ast) translations per constant name;
  1222 
  1223 * theorems involving oracles are now printed with a suffixed [!];
  1224 
  1225 
  1226 *** HOL ***
  1227 
  1228 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1229 
  1230 * HOL/inductive package reorganized and improved: now supports mutual
  1231 definitions such as
  1232 
  1233   inductive EVEN ODD
  1234     intrs
  1235       null "0 : EVEN"
  1236       oddI "n : EVEN ==> Suc n : ODD"
  1237       evenI "n : ODD ==> Suc n : EVEN"
  1238 
  1239 new theorem list "elims" contains an elimination rule for each of the
  1240 recursive sets; inductive definitions now handle disjunctive premises
  1241 correctly (also ZF);
  1242 
  1243 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1244 "mutual_induct" no longer exists - the induction rule is always
  1245 contained in "induct";
  1246 
  1247 
  1248 * HOL/datatype package re-implemented and greatly improved: now
  1249 supports mutually recursive datatypes such as
  1250 
  1251   datatype
  1252     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1253             | SUM ('a aexp) ('a aexp)
  1254             | DIFF ('a aexp) ('a aexp)
  1255             | NUM 'a
  1256   and
  1257     'a bexp = LESS ('a aexp) ('a aexp)
  1258             | AND ('a bexp) ('a bexp)
  1259             | OR ('a bexp) ('a bexp)
  1260 
  1261 as well as indirectly recursive datatypes such as
  1262 
  1263   datatype
  1264     ('a, 'b) term = Var 'a
  1265                   | App 'b ((('a, 'b) term) list)
  1266 
  1267 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1268 induction on mutually / indirectly recursive datatypes.
  1269 
  1270 Primrec equations are now stored in theory and can be accessed via
  1271 <function_name>.simps.
  1272 
  1273 INCOMPATIBILITIES:
  1274 
  1275   - Theories using datatypes must now have theory Datatype as an
  1276     ancestor.
  1277   - The specific <typename>.induct_tac no longer exists - use the
  1278     generic induct_tac instead.
  1279   - natE has been renamed to nat.exhaust - use exhaust_tac
  1280     instead of res_inst_tac ... natE. Note that the variable
  1281     names in nat.exhaust differ from the names in natE, this
  1282     may cause some "fragile" proofs to fail.
  1283   - The theorems split_<typename>_case and split_<typename>_case_asm
  1284     have been renamed to <typename>.split and <typename>.split_asm.
  1285   - Since default sorts of type variables are now handled correctly,
  1286     some datatype definitions may have to be annotated with explicit
  1287     sort constraints.
  1288   - Primrec definitions no longer require function name and type
  1289     of recursive argument.
  1290 
  1291 Consider using isatool fixdatatype to adapt your theories and proof
  1292 scripts to the new package (backup your sources first!).
  1293 
  1294 
  1295 * HOL/record package: considerably improved implementation; now
  1296 includes concrete syntax for record types, terms, updates; theorems
  1297 for surjective pairing and splitting !!-bound record variables; proof
  1298 support is as follows:
  1299 
  1300   1) standard conversions (selectors or updates applied to record
  1301 constructor terms) are part of the standard simpset;
  1302 
  1303   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1304 made part of standard simpset and claset via addIffs;
  1305 
  1306   3) a tactic for record field splitting (record_split_tac) is part of
  1307 the standard claset (addSWrapper);
  1308 
  1309 To get a better idea about these rules you may retrieve them via
  1310 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1311 the name of your record type.
  1312 
  1313 The split tactic 3) conceptually simplifies by the following rule:
  1314 
  1315   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1316 
  1317 Thus any record variable that is bound by meta-all will automatically
  1318 blow up into some record constructor term, consequently the
  1319 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1320 solve record problems automatically.
  1321 
  1322 
  1323 * reorganized the main HOL image: HOL/Integ and String loaded by
  1324 default; theory Main includes everything;
  1325 
  1326 * automatic simplification of integer sums and comparisons, using cancellation;
  1327 
  1328 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1329 
  1330 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1331 
  1332 * many new identities for unions, intersections, set difference, etc.;
  1333 
  1334 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1335 called split_if, split_split, split_sum_case and split_nat_case (to go
  1336 with add/delsplits);
  1337 
  1338 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1339 (?x::unit) = (); this is made part of the default simpset, which COULD
  1340 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1341 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1342 unit_abs_eta_conv is added in order to counter the effect of
  1343 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1344 %u.f();
  1345 
  1346 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1347 makes more sense);
  1348 
  1349 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1350   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1351   disjointness reasoning but breaking a few old proofs.
  1352 
  1353 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1354 to 'converse' from 'inverse' (for compatibility with ZF and some
  1355 literature);
  1356 
  1357 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1358 the well-founded relation;
  1359 
  1360 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1361     Compl A.  The "Compl" syntax remains available as input syntax for this
  1362     release ONLY.
  1363 
  1364 * HOL/Update: new theory of function updates:
  1365     f(a:=b) == %x. if x=a then b else f x
  1366 may also be iterated as in f(a:=b,c:=d,...);
  1367 
  1368 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1369 
  1370 * HOL/List:
  1371   - new function list_update written xs[i:=v] that updates the i-th
  1372     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1373   - new function `upt' written [i..j(] which generates the list
  1374     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1375     bound write [i..j], which is a shorthand for [i..j+1(].
  1376   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1377 
  1378 * HOL/Arith:
  1379   - removed 'pred' (predecessor) function;
  1380   - generalized some theorems about n-1;
  1381   - many new laws about "div" and "mod";
  1382   - new laws about greatest common divisors (see theory ex/Primes);
  1383 
  1384 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1385 instead of "inverse";
  1386 
  1387 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1388   of the multiset ordering;
  1389 
  1390 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1391   (not included by default);
  1392 
  1393 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1394 
  1395 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1396   programs, i.e. different program variables may have different types.
  1397 
  1398 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1399   [previously, this check worked only if the rewrite rule was unconditional]
  1400   Now rew can involve either definitions or equalities (either == or =).
  1401 
  1402 
  1403 *** ZF ***
  1404 
  1405 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1406   only the theorems proved on ZF.ML;
  1407 
  1408 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1409   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1410   disjointness reasoning but breaking a few old proofs.
  1411 
  1412 * ZF/Update: new theory of function updates
  1413     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1414   may also be iterated as in f(a:=b,c:=d,...);
  1415 
  1416 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1417 
  1418 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1419   [previously, this check worked only if the rewrite rule was unconditional]
  1420   Now rew can involve either definitions or equalities (either == or =).
  1421 
  1422 * case_tac provided for compatibility with HOL
  1423     (like the old excluded_middle_tac, but with subgoals swapped)
  1424 
  1425 
  1426 *** Internal programming interfaces ***
  1427 
  1428 * Pure: several new basic modules made available for general use, see
  1429 also src/Pure/README;
  1430 
  1431 * improved the theory data mechanism to support encapsulation (data
  1432 kind name replaced by private Object.kind, acting as authorization
  1433 key); new type-safe user interface via functor TheoryDataFun; generic
  1434 print_data function becomes basically useless;
  1435 
  1436 * removed global_names compatibility flag -- all theory declarations
  1437 are qualified by default;
  1438 
  1439 * module Pure/Syntax now offers quote / antiquote translation
  1440 functions (useful for Hoare logic etc. with implicit dependencies);
  1441 see HOL/ex/Antiquote for an example use;
  1442 
  1443 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1444 cterm -> thm;
  1445 
  1446 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1447 subgoal;
  1448 
  1449 * Display.print_goals function moved to Locale.print_goals;
  1450 
  1451 * standard print function for goals supports current_goals_markers
  1452 variable for marking begin of proof, end of proof, start of goal; the
  1453 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1454 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1455 for example;
  1456 
  1457 
  1458 
  1459 New in Isabelle98 (January 1998)
  1460 --------------------------------
  1461 
  1462 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1463 
  1464 * changed lexical syntax of terms / types: dots made part of long
  1465 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1466 
  1467 * simpset (and claset) reference variable replaced by functions
  1468 simpset / simpset_ref;
  1469 
  1470 * no longer supports theory aliases (via merge) and non-trivial
  1471 implicit merge of thms' signatures;
  1472 
  1473 * most internal names of constants changed due to qualified names;
  1474 
  1475 * changed Pure/Sequence interface (see Pure/seq.ML);
  1476 
  1477 
  1478 *** General Changes ***
  1479 
  1480 * hierachically structured name spaces (for consts, types, axms, thms
  1481 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1482 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1483 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1484 long_names for fully qualified output names; NOTE: ML programs
  1485 (special tactics, packages etc.) referring to internal names may have
  1486 to be adapted to cope with fully qualified names; in case of severe
  1487 backward campatibility problems try setting 'global_names' at compile
  1488 time to have enrything declared within a flat name space; one may also
  1489 fine tune name declarations in theories via the 'global' and 'local'
  1490 section;
  1491 
  1492 * reimplemented the implicit simpset and claset using the new anytype
  1493 data filed in signatures; references simpset:simpset ref etc. are
  1494 replaced by functions simpset:unit->simpset and
  1495 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1496 to patch your ML files accordingly;
  1497 
  1498 * HTML output now includes theory graph data for display with Java
  1499 applet or isatool browser; data generated automatically via isatool
  1500 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1501 
  1502 * defs may now be conditional; improved rewrite_goals_tac to handle
  1503 conditional equations;
  1504 
  1505 * defs now admits additional type arguments, using TYPE('a) syntax;
  1506 
  1507 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1508 creates a new theory node; implicit merge of thms' signatures is
  1509 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1510 transfer:theory->thm->thm in (rare) cases;
  1511 
  1512 * improved handling of draft signatures / theories; draft thms (and
  1513 ctyps, cterms) are automatically promoted to real ones;
  1514 
  1515 * slightly changed interfaces for oracles: admit many per theory, named
  1516 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1517 
  1518 * print_goals: optional output of const types (set show_consts and
  1519 show_types);
  1520 
  1521 * improved output of warnings (###) and errors (***);
  1522 
  1523 * subgoal_tac displays a warning if the new subgoal has type variables;
  1524 
  1525 * removed old README and Makefiles;
  1526 
  1527 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1528 
  1529 * removed obsolete init_pps and init_database;
  1530 
  1531 * deleted the obsolete tactical STATE, which was declared by
  1532     fun STATE tacfun st = tacfun st st;
  1533 
  1534 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1535 (which abbreviates $HOME);
  1536 
  1537 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1538 use isatool fixseq to adapt your ML programs (this works for fully
  1539 qualified references to the Sequence structure only!);
  1540 
  1541 * use_thy no longer requires writable current directory; it always
  1542 reloads .ML *and* .thy file, if either one is out of date;
  1543 
  1544 
  1545 *** Classical Reasoner ***
  1546 
  1547 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1548 tactics that use classical reasoning to simplify a subgoal without
  1549 splitting it into several subgoals;
  1550 
  1551 * Safe_tac: like safe_tac but uses the default claset;
  1552 
  1553 
  1554 *** Simplifier ***
  1555 
  1556 * added simplification meta rules:
  1557     (asm_)(full_)simplify: simpset -> thm -> thm;
  1558 
  1559 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1560 logics (again);
  1561 
  1562 * added prems argument to simplification procedures;
  1563 
  1564 * HOL, FOL, ZF: added infix function `addsplits':
  1565   instead of `<simpset> setloop (split_tac <thms>)'
  1566   you can simply write `<simpset> addsplits <thms>'
  1567 
  1568 
  1569 *** Syntax ***
  1570 
  1571 * TYPE('a) syntax for type reflection terms;
  1572 
  1573 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1574 
  1575 * pretty printer: changed order of mixfix annotation preference (again!);
  1576 
  1577 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1578 
  1579 
  1580 *** HOL ***
  1581 
  1582 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1583   with `addloop' of the simplifier to faciliate case splitting in premises.
  1584 
  1585 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1586 
  1587 * HOL/Auth: new protocol proofs including some for the Internet
  1588   protocol TLS;
  1589 
  1590 * HOL/Map: new theory of `maps' a la VDM;
  1591 
  1592 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1593 cancelling out common nat summands from =, <, <= (in)equalities, or
  1594 differences; simplification procedures nat_cancel_factor for
  1595 cancelling common factor from =, <, <= (in)equalities over natural
  1596 sums; nat_cancel contains both kinds of procedures, it is installed by
  1597 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1598 
  1599 * HOL/simplifier: terms of the form
  1600   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1601   are rewritten to
  1602   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1603   and those of the form
  1604   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1605   are rewritten to
  1606   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1607 
  1608 * HOL/datatype
  1609   Each datatype `t' now comes with a theorem `split_t_case' 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 
  1617   and a theorem `split_t_case_asm' of the form
  1618 
  1619   P(t_case f1 ... fn x) =
  1620     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1621         ...
  1622        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1623      )
  1624   which can be added to a simpset via `addsplits'. The existing theorems
  1625   expand_list_case and expand_option_case have been renamed to
  1626   split_list_case and split_option_case.
  1627 
  1628 * HOL/Arithmetic:
  1629   - `pred n' is automatically converted to `n-1'.
  1630     Users are strongly encouraged not to use `pred' any longer,
  1631     because it will disappear altogether at some point.
  1632   - Users are strongly encouraged to write "0 < n" rather than
  1633     "n ~= 0". Theorems and proof tools have been modified towards this
  1634     `standard'.
  1635 
  1636 * HOL/Lists:
  1637   the function "set_of_list" has been renamed "set" (and its theorems too);
  1638   the function "nth" now takes its arguments in the reverse order and
  1639   has acquired the infix notation "!" as in "xs!n".
  1640 
  1641 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1642 
  1643 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1644   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1645 
  1646 * HOL/record: extensible records with schematic structural subtyping
  1647 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1648 still lacks various theorems and concrete record syntax;
  1649 
  1650 
  1651 *** HOLCF ***
  1652 
  1653 * removed "axioms" and "generated by" sections;
  1654 
  1655 * replaced "ops" section by extended "consts" section, which is capable of
  1656   handling the continuous function space "->" directly;
  1657 
  1658 * domain package:
  1659   . proves theorems immediately and stores them in the theory,
  1660   . creates hierachical name space,
  1661   . now uses normal mixfix annotations (instead of cinfix...),
  1662   . minor changes to some names and values (for consistency),
  1663   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1664   . separator between mutual domain defs: changed "," to "and",
  1665   . improved handling of sort constraints;  now they have to
  1666     appear on the left-hand side of the equations only;
  1667 
  1668 * fixed LAM <x,y,zs>.b syntax;
  1669 
  1670 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1671 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1672 
  1673 
  1674 *** FOL and ZF ***
  1675 
  1676 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1677   with `addloop' of the simplifier to faciliate case splitting in premises.
  1678 
  1679 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1680 in HOL, they strip ALL and --> from proved theorems;
  1681 
  1682 
  1683 
  1684 New in Isabelle94-8 (May 1997)
  1685 ------------------------------
  1686 
  1687 *** General Changes ***
  1688 
  1689 * new utilities to build / run / maintain Isabelle etc. (in parts
  1690 still somewhat experimental); old Makefiles etc. still functional;
  1691 
  1692 * new 'Isabelle System Manual';
  1693 
  1694 * INSTALL text, together with ./configure and ./build scripts;
  1695 
  1696 * reimplemented type inference for greater efficiency, better error
  1697 messages and clean internal interface;
  1698 
  1699 * prlim command for dealing with lots of subgoals (an easier way of
  1700 setting goals_limit);
  1701 
  1702 
  1703 *** Syntax ***
  1704 
  1705 * supports alternative (named) syntax tables (parser and pretty
  1706 printer); internal interface is provided by add_modesyntax(_i);
  1707 
  1708 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1709 be used in conjunction with the Isabelle symbol font; uses the
  1710 "symbols" syntax table;
  1711 
  1712 * added token_translation interface (may translate name tokens in
  1713 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1714 the current print_mode); IMPORTANT: user print translation functions
  1715 are responsible for marking newly introduced bounds
  1716 (Syntax.mark_boundT);
  1717 
  1718 * token translations for modes "xterm" and "xterm_color" that display
  1719 names in bold, underline etc. or colors (which requires a color
  1720 version of xterm);
  1721 
  1722 * infixes may now be declared with names independent of their syntax;
  1723 
  1724 * added typed_print_translation (like print_translation, but may
  1725 access type of constant);
  1726 
  1727 
  1728 *** Classical Reasoner ***
  1729 
  1730 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1731 some limitations.  Blast_tac...
  1732   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1733   + ignores elimination rules that don't have the correct format
  1734         (the conclusion MUST be a formula variable)
  1735   + ignores types, which can make HOL proofs fail
  1736   + rules must not require higher-order unification, e.g. apply_type in ZF
  1737     [message "Function Var's argument not a bound variable" relates to this]
  1738   + its proof strategy is more general but can actually be slower
  1739 
  1740 * substitution with equality assumptions no longer permutes other
  1741 assumptions;
  1742 
  1743 * minor changes in semantics of addafter (now called addaltern); renamed
  1744 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1745 (and access functions for it);
  1746 
  1747 * improved combination of classical reasoner and simplifier:
  1748   + functions for handling clasimpsets
  1749   + improvement of addss: now the simplifier is called _after_ the
  1750     safe steps.
  1751   + safe variant of addss called addSss: uses safe simplifications
  1752     _during_ the safe steps. It is more complete as it allows multiple
  1753     instantiations of unknowns (e.g. with slow_tac).
  1754 
  1755 *** Simplifier ***
  1756 
  1757 * added interface for simplification procedures (functions that
  1758 produce *proven* rewrite rules on the fly, depending on current
  1759 redex);
  1760 
  1761 * ordering on terms as parameter (used for ordered rewriting);
  1762 
  1763 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1764 
  1765 * the solver is now split into a safe and an unsafe part.
  1766 This should be invisible for the normal user, except that the
  1767 functions setsolver and addsolver have been renamed to setSolver and
  1768 addSolver; added safe_asm_full_simp_tac;
  1769 
  1770 
  1771 *** HOL ***
  1772 
  1773 * a generic induction tactic `induct_tac' which works for all datatypes and
  1774 also for type `nat';
  1775 
  1776 * a generic case distinction tactic `exhaust_tac' which works for all
  1777 datatypes and also for type `nat';
  1778 
  1779 * each datatype comes with a function `size';
  1780 
  1781 * patterns in case expressions allow tuple patterns as arguments to
  1782 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1783 
  1784 * primrec now also works with type nat;
  1785 
  1786 * recdef: a new declaration form, allows general recursive functions to be
  1787 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1788 
  1789 * the constant for negation has been renamed from "not" to "Not" to
  1790 harmonize with FOL, ZF, LK, etc.;
  1791 
  1792 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1793 infinite lists;
  1794 
  1795 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1796 
  1797 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1798 problems in commutative rings, using axiomatic type classes for + and *;
  1799 
  1800 * more examples in HOL/MiniML and HOL/Auth;
  1801 
  1802 * more default rewrite rules for quantifiers, union/intersection;
  1803 
  1804 * a new constant `arbitrary == @x.False';
  1805 
  1806 * HOLCF/IOA replaces old HOL/IOA;
  1807 
  1808 * HOLCF changes: derived all rules and arities
  1809   + axiomatic type classes instead of classes
  1810   + typedef instead of faking type definitions
  1811   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1812   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1813   + eliminated the types void, one, tr
  1814   + use unit lift and bool lift (with translations) instead of one and tr
  1815   + eliminated blift from Lift3.thy (use Def instead of blift)
  1816   all eliminated rules are derived as theorems --> no visible changes ;
  1817 
  1818 
  1819 *** ZF ***
  1820 
  1821 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1822 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1823 as ZF_cs addSIs [equalityI];
  1824 
  1825 
  1826 
  1827 New in Isabelle94-7 (November 96)
  1828 ---------------------------------
  1829 
  1830 * allowing negative levels (as offsets) in prlev and choplev;
  1831 
  1832 * super-linear speedup for large simplifications;
  1833 
  1834 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1835 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1836 FAIL); can suppress it using the command Delsimps (ex_simps @
  1837 all_simps); De Morgan laws are also now included, by default;
  1838 
  1839 * improved printing of ==>  :  ~:
  1840 
  1841 * new object-logic "Sequents" adds linear logic, while replacing LK
  1842 and Modal (thanks to Sara Kalvala);
  1843 
  1844 * HOL/Auth: correctness proofs for authentication protocols;
  1845 
  1846 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1847 examples on HOL/Auth);
  1848 
  1849 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1850 the rewriter and classical reasoner simultaneously;
  1851 
  1852 * function uresult no longer returns theorems in "standard" format;
  1853 regain previous version by: val uresult = standard o uresult;
  1854 
  1855 
  1856 
  1857 New in Isabelle94-6
  1858 -------------------
  1859 
  1860 * oracles -- these establish an interface between Isabelle and trusted
  1861 external reasoners, which may deliver results as theorems;
  1862 
  1863 * proof objects (in particular record all uses of oracles);
  1864 
  1865 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1866 
  1867 * "constdefs" section in theory files;
  1868 
  1869 * "primrec" section (HOL) no longer requires names;
  1870 
  1871 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1872 
  1873 
  1874 
  1875 New in Isabelle94-5
  1876 -------------------
  1877 
  1878 * reduced space requirements;
  1879 
  1880 * automatic HTML generation from theories;
  1881 
  1882 * theory files no longer require "..." (quotes) around most types;
  1883 
  1884 * new examples, including two proofs of the Church-Rosser theorem;
  1885 
  1886 * non-curried (1994) version of HOL is no longer distributed;
  1887 
  1888 
  1889 
  1890 New in Isabelle94-4
  1891 -------------------
  1892 
  1893 * greatly reduced space requirements;
  1894 
  1895 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1896 
  1897 * searchable theorem database (see the section "Retrieving theorems" on
  1898 page 8 of the Reference Manual);
  1899 
  1900 * new examples, including Grabczewski's monumental case study of the
  1901 Axiom of Choice;
  1902 
  1903 * The previous version of HOL renamed to Old_HOL;
  1904 
  1905 * The new version of HOL (previously called CHOL) uses a curried syntax
  1906 for functions.  Application looks like f a b instead of f(a,b);
  1907 
  1908 * Mutually recursive inductive definitions finally work in HOL;
  1909 
  1910 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1911 translates to the operator "split";
  1912 
  1913 
  1914 
  1915 New in Isabelle94-3
  1916 -------------------
  1917 
  1918 * new infix operator, addss, allowing the classical reasoner to
  1919 perform simplification at each step of its search.  Example:
  1920         fast_tac (cs addss ss)
  1921 
  1922 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1923 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1924 look like (a,b) instead of <a,b>;
  1925 
  1926 * PLEASE NOTE: CHOL will eventually replace HOL!
  1927 
  1928 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1929 It translates to the operator "split".  A new theory of integers is available;
  1930 
  1931 * In ZF, integer numerals now denote two's-complement binary integers.
  1932 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1933 
  1934 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1935 of the Axiom of Choice;
  1936 
  1937 
  1938 
  1939 New in Isabelle94-2
  1940 -------------------
  1941 
  1942 * Significantly faster resolution;
  1943 
  1944 * the different sections in a .thy file can now be mixed and repeated
  1945 freely;
  1946 
  1947 * Database of theorems for FOL, HOL and ZF.  New
  1948 commands including qed, qed_goal and bind_thm store theorems in the database.
  1949 
  1950 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1951 a given theory (thms_of), or find out what theory a theorem was proved in
  1952 (theory_of_thm);
  1953 
  1954 * Bugs fixed in the inductive definition and datatype packages;
  1955 
  1956 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1957 and HOL_dup_cs obsolete;
  1958 
  1959 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1960 have been removed;
  1961 
  1962 * Simpler definition of function space in ZF;
  1963 
  1964 * new results about cardinal and ordinal arithmetic in ZF;
  1965 
  1966 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1967 types;
  1968 
  1969 
  1970 $Id$