NEWS
author wenzelm
Tue Oct 23 19:12:37 2001 +0200 (2001-10-23)
changeset 11899 e543b0f01a58
parent 11864 371ce685b0ec
child 11921 2a0e9622dc51
permissions -rw-r--r--
* Pure: removed obsolete 'exported' attribute;
* Pure: dummy pattern "_" in is/let is now automatically ``lifted''
over bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2001 (?? 2001)
     6 -----------------------------
     7 
     8 *** Document preparation ***
     9 
    10 * greatly simplified document preparation setup, including more
    11 graceful interpretation of isatool usedir -i/-d/-D options, and more
    12 instructive isatool mkdir; users should basically be able to get
    13 started with "isatool mkdir Test && isatool make";
    14 
    15 * theory dependency graph may now be incorporated into documents;
    16 isatool usedir -g true will produce session_graph.eps/.pdf for use
    17 with \includegraphics of LaTeX;
    18 
    19 * proper spacing of consecutive markup elements, especially text
    20 blocks after section headings;
    21 
    22 * support bold style (for single symbols only), input syntax is like
    23 this: "\<^bold>\<alpha>" or "\<^bold>A";
    24 
    25 * \<bullet> is now output as bold \cdot by default, which looks much
    26 better in printed text;
    27 
    28 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    29 note that these symbols are currently unavailable in Proof General /
    30 X-Symbol;
    31 
    32 
    33 *** Isar ***
    34 
    35 * improved proof by cases and induction:
    36   - 'case' command admits impromptu naming of parameters (such as
    37     "case (Suc n)");
    38   - 'induct' method divinates rule instantiation from the inductive
    39     claim; no longer requires excessive ?P bindings for proper
    40     instantiation of cases;
    41   - 'induct' method properly enumerates all possibilities of set/type
    42     rules; as a consequence facts may be also passed through *type*
    43     rules without further ado;
    44   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    45   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    46   - moved induct/cases attributes to Pure, methods to Provers;
    47   - generic method setup instantiated for FOL and HOL;
    48 
    49 * Pure: renamed "antecedent" case to "rule_context";
    50 
    51 * Pure: added 'corollary' command;
    52 
    53 * Pure: fixed 'token_translation' command;
    54 
    55 * Pure: removed obsolete 'exported' attribute;
    56 
    57 * Pure: dummy pattern "_" in is/let is now automatically ``lifted''
    58 over bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
    59 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
    60 
    61 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
    62 
    63 * HOL: 'recdef' now fails on unfinished automated proofs, use
    64 "(permissive)" option to recover old behavior;
    65 
    66 * HOL: 'inductive' now longer features separate (collective)
    67 attributes for 'intros';
    68 
    69 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
    70 
    71 
    72 *** HOL ***
    73 
    74 * HOL: moved over to sane numeral syntax; the new policy is as
    75 follows:
    76 
    77   - 0 and 1 are polymorphic constants, which are defined on any
    78   numeric type (nat, int, real etc.);
    79 
    80   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
    81   binary representation internally;
    82 
    83   - type nat has special constructor Suc, and generally prefers Suc 0
    84   over 1::nat and Suc (Suc 0) over 2::nat;
    85 
    86 This change may cause significant INCOMPATIBILITIES; here are some
    87 hints on converting existing sources:
    88 
    89   - due to the new "num" token, "-0" and "-1" etc. are now atomic
    90   entities, so expressions involving "-" (unary or binary minus) need
    91   to be spaced properly;
    92 
    93   - existing occurrences of "1" may need to be constraint "1::nat" or
    94   even replaced by Suc 0; similar for old "2";
    95 
    96   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
    97 
    98   - remove all special provisions on numerals in proofs;
    99 
   100 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   101 (beware of argument permutation!);
   102 
   103 * HOL: linorder_less_split superseded by linorder_cases;
   104 
   105 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   106 to peripheral theory "Hilbert_Choice";
   107 
   108 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   109 in this (rare) case use:
   110 
   111   delSWrapper "split_all_tac"
   112   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   113 
   114 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   115 MAY FAIL;
   116 
   117 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   118 Isabelle's type classes, ^ on functions and relations has too general
   119 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   120 necessary to attach explicit type constraints;
   121 
   122 * HOL: syntax translations now work properly with numerals and records
   123 expressions;
   124 
   125 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   126 Florian Kammüller;
   127 
   128 * HOL: eliminated global items
   129 
   130   const "()" -> "Product_Type.Unity"
   131   type "unit" -> "Product_Type.unit"
   132 
   133 
   134 *** ZF ***
   135 
   136 * ZF: the integer library now covers quotients and remainders, with
   137 many laws relating division to addition, multiplication, etc.;
   138 
   139 
   140 *** General ***
   141 
   142 * kernel: meta-level proof terms (by Stefan Berghofer), see also ref
   143 manual;
   144 
   145 * classical reasoner: renamed addaltern to addafter, addSaltern to
   146 addSafter;
   147 
   148 * syntax: new token syntax "num" for plain numerals (without "#" of
   149 "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now separate
   150 tokens, so expressions involving minus need to be spaced properly;
   151 
   152 * syntax: support non-oriented infixes;
   153 
   154 * syntax: print modes "type_brackets" and "no_type_brackets" control
   155 output of nested => (types); the default behavior is "type_brackets";
   156 
   157 * syntax: builtin parse translation for "_constify" turns valued
   158 tokens into AST constants;
   159 
   160 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   161 
   162 * system: Proof General keywords specification is now part of the
   163 Isabelle distribution (see etc/isar-keywords.el);
   164 
   165 * system: smart selection of Isabelle process versus Isabelle
   166 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   167 run both "isabelle" and "Isabelle" even if file names are badly
   168 damaged (executable inspects the case of the first letter of its own
   169 name); added separate "isabelle-process" and "isabelle-interface";
   170 
   171 
   172 
   173 New in Isabelle99-2 (February 2001)
   174 -----------------------------------
   175 
   176 *** Overview of INCOMPATIBILITIES ***
   177 
   178 * HOL: please note that theories in the Library and elsewhere often use the
   179 new-style (Isar) format; to refer to their theorems in an ML script you must
   180 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   181 
   182 * HOL: inductive package no longer splits induction rule aggressively,
   183 but only as far as specified by the introductions given; the old
   184 format may be recovered via ML function complete_split_rule or attribute
   185 'split_rule (complete)';
   186 
   187 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   188 gfp_Tarski to gfp_unfold;
   189 
   190 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   191 
   192 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   193 relation); infix "^^" has been renamed "``"; infix "``" has been
   194 renamed "`"; "univalent" has been renamed "single_valued";
   195 
   196 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   197 operation;
   198 
   199 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   200 
   201 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   202 
   203 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   204 consequence, it is no longer monotonic wrt. the local goal context
   205 (which is now passed through the inductive cases);
   206 
   207 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   208 \<gg> to \<ggreater>;
   209 
   210 
   211 *** Document preparation ***
   212 
   213 * \isabellestyle{NAME} selects version of Isabelle output (currently
   214 available: are "it" for near math-mode best-style output, "sl" for
   215 slanted text style, and "tt" for plain type-writer; if no
   216 \isabellestyle command is given, output is according to slanted
   217 type-writer);
   218 
   219 * support sub/super scripts (for single symbols only), input syntax is
   220 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   221 
   222 * some more standard symbols; see Appendix A of the system manual for
   223 the complete list of symbols defined in isabellesym.sty;
   224 
   225 * improved isabelle style files; more abstract symbol implementation
   226 (should now use \isamath{...} and \isatext{...} in custom symbol
   227 definitions);
   228 
   229 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   230 state; Note that presentation of goal states does not conform to
   231 actual human-readable proof documents.  Please do not include goal
   232 states into document output unless you really know what you are doing!
   233 
   234 * proper indentation of antiquoted output with proportional LaTeX
   235 fonts;
   236 
   237 * no_document ML operator temporarily disables LaTeX document
   238 generation;
   239 
   240 * isatool unsymbolize tunes sources for plain ASCII communication;
   241 
   242 
   243 *** Isar ***
   244 
   245 * Pure: Isar now suffers initial goal statements to contain unbound
   246 schematic variables (this does not conform to actual readable proof
   247 documents, due to unpredictable outcome and non-compositional proof
   248 checking); users who know what they are doing may use schematic goals
   249 for Prolog-style synthesis of proven results;
   250 
   251 * Pure: assumption method (an implicit finishing) now handles actual
   252 rules as well;
   253 
   254 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   255 initial goal, declare "that" only as Pure intro (only for single
   256 steps); the "that" rule assumption may now be involved in implicit
   257 finishing, thus ".." becomes a feasible for trivial obtains;
   258 
   259 * Pure: default proof step now includes 'intro_classes'; thus trivial
   260 instance proofs may be performed by "..";
   261 
   262 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   263 statements as well;
   264 
   265 * Pure: more robust selection of calculational rules;
   266 
   267 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   268 rule (as well as the assumption rule);
   269 
   270 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   271 lemmas, using the graph browser tool;
   272 
   273 * Pure: predict failure of "show" in interactive mode;
   274 
   275 * Pure: 'thms_containing' now takes actual terms as arguments;
   276 
   277 * HOL: improved method 'induct' --- now handles non-atomic goals
   278 (potential INCOMPATIBILITY); tuned error handling;
   279 
   280 * HOL: cases and induct rules now provide explicit hints about the
   281 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   282 any remaining facts are inserted into the goal verbatim;
   283 
   284 * HOL: local contexts (aka cases) may now contain term bindings as
   285 well; the 'cases' and 'induct' methods new provide a ?case binding for
   286 the result to be shown in each case;
   287 
   288 * HOL: added 'recdef_tc' command;
   289 
   290 * isatool convert assists in eliminating legacy ML scripts;
   291 
   292 
   293 *** HOL ***
   294 
   295 * HOL/Library: a collection of generic theories to be used together
   296 with main HOL; the theory loader path already includes this directory
   297 by default; the following existing theories have been moved here:
   298 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   299 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   300 
   301 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   302 modelling and verification task performed in Isabelle/HOL +
   303 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   304 
   305 * HOL/Algebra: special summation operator SUM no longer exists, it has
   306 been replaced by setsum; infix 'assoc' now has priority 50 (like
   307 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   308 'domain', this makes the theory consistent with mathematical
   309 literature;
   310 
   311 * HOL basics: added overloaded operations "inverse" and "divide"
   312 (infix "/"), syntax for generic "abs" operation, generic summation
   313 operator \<Sum>;
   314 
   315 * HOL/typedef: simplified package, provide more useful rules (see also
   316 HOL/subset.thy);
   317 
   318 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   319 now expressed as a proper nested rule (old-style tactic scripts may
   320 require atomize_strip_tac to cope with non-atomic premises);
   321 
   322 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   323 to "split_conv" (old name still available for compatibility);
   324 
   325 * HOL: improved concrete syntax for strings (e.g. allows translation
   326 rules with string literals);
   327 
   328 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   329 and Fleuriot's mechanization of analysis;
   330 
   331 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   332 
   333 
   334 *** CTT ***
   335 
   336 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   337 "lam" is displayed as TWO lambda-symbols
   338 
   339 * CTT: theory Main now available, containing everything (that is, Bool
   340 and Arith);
   341 
   342 
   343 *** General ***
   344 
   345 * Pure: the Simplifier has been implemented properly as a derived rule
   346 outside of the actual kernel (at last!); the overall performance
   347 penalty in practical applications is about 50%, while reliability of
   348 the Isabelle inference kernel has been greatly improved;
   349 
   350 * print modes "brackets" and "no_brackets" control output of nested =>
   351 (types) and ==> (props); the default behaviour is "brackets";
   352 
   353 * Provers: fast_tac (and friends) now handle actual object-logic rules
   354 as assumptions as well;
   355 
   356 * system: support Poly/ML 4.0;
   357 
   358 * system: isatool install handles KDE version 1 or 2;
   359 
   360 
   361 
   362 New in Isabelle99-1 (October 2000)
   363 ----------------------------------
   364 
   365 *** Overview of INCOMPATIBILITIES ***
   366 
   367 * HOL: simplification of natural numbers is much changed; to partly
   368 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   369 issue the following ML commands:
   370 
   371   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   372   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   373 
   374 * HOL: simplification no longer dives into case-expressions; this is
   375 controlled by "t.weak_case_cong" for each datatype t;
   376 
   377 * HOL: nat_less_induct renamed to less_induct;
   378 
   379 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   380 fixsome to patch .thy and .ML sources automatically;
   381 
   382   select_equality  -> some_equality
   383   select_eq_Ex     -> some_eq_ex
   384   selectI2EX       -> someI2_ex
   385   selectI2         -> someI2
   386   selectI          -> someI
   387   select1_equality -> some1_equality
   388   Eps_sym_eq       -> some_sym_eq_trivial
   389   Eps_eq           -> some_eq_trivial
   390 
   391 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   392 
   393 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   394 instead);
   395 
   396 * HOL: the recursion equations generated by 'recdef' are now called
   397 f.simps instead of f.rules;
   398 
   399 * HOL: qed_spec_mp now also handles bounded ALL as well;
   400 
   401 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   402 sometimes be needed;
   403 
   404 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   405 
   406 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   407 
   408 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   409 product is now "<*>" instead of "Times"; the lexicographic product is
   410 now "<*lex*>" instead of "**";
   411 
   412 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   413 of main HOL, but was unused); better use HOL's datatype package;
   414 
   415 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   416 the old syntax may be recovered as follows:
   417 
   418   syntax (symbols)
   419     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   420       (infixl "\\<oplus>" 100)
   421 
   422 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   423 
   424 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   425 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   426 internally;
   427 
   428 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   429 changed from A/r to A//r;
   430 
   431 * ZF: new treatment of arithmetic (nat & int) may break some old
   432 proofs;
   433 
   434 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   435 rulify -> rule_format, elimify -> elim_format, ...);
   436 
   437 * Isar/Provers: intro/elim/dest attributes changed; renamed
   438 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   439 should have to change intro!! to intro? only); replaced "delrule" by
   440 "rule del";
   441 
   442 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   443 
   444 * Provers: strengthened force_tac by using new first_best_tac;
   445 
   446 * LaTeX document preparation: several changes of isabelle.sty (see
   447 lib/texinputs);
   448 
   449 
   450 *** Document preparation ***
   451 
   452 * formal comments (text blocks etc.) in new-style theories may now
   453 contain antiquotations of thm/prop/term/typ/text to be presented
   454 according to latex print mode; concrete syntax is like this:
   455 @{term[show_types] "f(x) = a + x"};
   456 
   457 * isatool mkdir provides easy setup of Isabelle session directories,
   458 including proper document sources;
   459 
   460 * generated LaTeX sources are now deleted after successful run
   461 (isatool document -c); may retain a copy somewhere else via -D option
   462 of isatool usedir;
   463 
   464 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   465 style files, achieving self-contained LaTeX sources and simplifying
   466 LaTeX debugging;
   467 
   468 * old-style theories now produce (crude) LaTeX output as well;
   469 
   470 * browser info session directories are now self-contained (may be put
   471 on WWW server seperately); improved graphs of nested sessions; removed
   472 graph for 'all sessions';
   473 
   474 * several improvements in isabelle style files; \isabellestyle{it}
   475 produces fake math mode output; \isamarkupheader is now \section by
   476 default; see lib/texinputs/isabelle.sty etc.;
   477 
   478 
   479 *** Isar ***
   480 
   481 * Isar/Pure: local results and corresponding term bindings are now
   482 subject to Hindley-Milner polymorphism (similar to ML); this
   483 accommodates incremental type-inference very nicely;
   484 
   485 * Isar/Pure: new derived language element 'obtain' supports
   486 generalized existence reasoning;
   487 
   488 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   489 support accumulation of results, without applying any rules yet;
   490 useful to collect intermediate results without explicit name
   491 references, and for use with transitivity rules with more than 2
   492 premises;
   493 
   494 * Isar/Pure: scalable support for case-analysis type proofs: new
   495 'case' language element refers to local contexts symbolically, as
   496 produced by certain proof methods; internally, case names are attached
   497 to theorems as "tags";
   498 
   499 * Isar/Pure: theory command 'hide' removes declarations from
   500 class/type/const name spaces;
   501 
   502 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   503 indicate potential overloading;
   504 
   505 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   506 
   507 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   508 "{a,b,c}" instead of {a,b,c};
   509 
   510 * Isar/Pure now provides its own version of intro/elim/dest
   511 attributes; useful for building new logics, but beware of confusion
   512 with the version in Provers/classical;
   513 
   514 * Isar/Pure: the local context of (non-atomic) goals is provided via
   515 case name 'antecedent';
   516 
   517 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   518 to the current context is now done automatically);
   519 
   520 * Isar/Pure: theory command 'method_setup' provides a simple interface
   521 for definining proof methods in ML;
   522 
   523 * Isar/Provers: intro/elim/dest attributes changed; renamed
   524 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   525 most cases, one should have to change intro!! to intro? only);
   526 replaced "delrule" by "rule del";
   527 
   528 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   529 'symmetric' attribute (the latter supercedes [RS sym]);
   530 
   531 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   532 method modifier); 'simp' method: 'only:' modifier removes loopers as
   533 well (including splits);
   534 
   535 * Isar/Provers: Simplifier and Classical methods now support all kind
   536 of modifiers used in the past, including 'cong', 'iff', etc.
   537 
   538 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   539 of Simplifier and Classical reasoner);
   540 
   541 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   542 now support named cases; major packages (inductive, datatype, primrec,
   543 recdef) support case names and properly name parameters;
   544 
   545 * Isar/HOL: new transitivity rules for substitution in inequalities --
   546 monotonicity conditions are extracted to be proven at end of
   547 calculations;
   548 
   549 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   550 method anyway;
   551 
   552 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   553 split_if split_if_asm; datatype package provides theorems foo.splits =
   554 foo.split foo.split_asm for each datatype;
   555 
   556 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   557 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   558 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   559 use "(cases (simplified))" method in proper proof texts);
   560 
   561 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   562 
   563 * Isar: names of theorems etc. may be natural numbers as well;
   564 
   565 * Isar: 'pr' command: optional arguments for goals_limit and
   566 ProofContext.prems_limit; no longer prints theory contexts, but only
   567 proof states;
   568 
   569 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   570 additional print modes to be specified; e.g. "pr(latex)" will print
   571 proof state according to the Isabelle LaTeX style;
   572 
   573 * Isar: improved support for emulating tactic scripts, including proof
   574 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   575 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   576 (for HOL datatypes);
   577 
   578 * Isar: simplified (more robust) goal selection of proof methods: 1st
   579 goal, all goals, or explicit goal specifier (tactic emulation); thus
   580 'proof method scripts' have to be in depth-first order;
   581 
   582 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   583 
   584 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   585 should instead use individual commands for printing items
   586 (print_commands, print_methods etc.);
   587 
   588 * Isar: added 'nothing' --- the empty list of theorems;
   589 
   590 
   591 *** HOL ***
   592 
   593 * HOL/MicroJava: formalization of a fragment of Java, together with a
   594 corresponding virtual machine and a specification of its bytecode
   595 verifier and a lightweight bytecode verifier, including proofs of
   596 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   597 Cornelia Pusch (see also the homepage of project Bali at
   598 http://isabelle.in.tum.de/Bali/);
   599 
   600 * HOL/Algebra: new theory of rings and univariate polynomials, by
   601 Clemens Ballarin;
   602 
   603 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   604 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   605 Rasmussen;
   606 
   607 * HOL/Lattice: fundamental concepts of lattice theory and order
   608 structures, including duals, properties of bounds versus algebraic
   609 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   610 Theorem for complete lattices etc.; may also serve as a demonstration
   611 for abstract algebraic reasoning using axiomatic type classes, and
   612 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   613 
   614 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   615 von Oheimb;
   616 
   617 * HOL/IMPP: extension of IMP with local variables and mutually
   618 recursive procedures, by David von Oheimb;
   619 
   620 * HOL/Lambda: converted into new-style theory and document;
   621 
   622 * HOL/ex/Multiquote: example of multiple nested quotations and
   623 anti-quotations -- basically a generalized version of de-Bruijn
   624 representation; very useful in avoiding lifting of operations;
   625 
   626 * HOL/record: added general record equality rule to simpset; fixed
   627 select-update simplification procedure to handle extended records as
   628 well; admit "r" as field name;
   629 
   630 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   631 other numeric types and also as the identity of groups, rings, etc.;
   632 
   633 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   634 Types nat and int belong to this axclass;
   635 
   636 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   637    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   638    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   639   two terms #m*u and #n*u are replaced by #(m+n)*u
   640     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   641   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   642     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   643 
   644 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   645 powerful prover for predicate logic but knows nothing of clasets; see
   646 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   647 
   648 * HOL: new version of "case_tac" subsumes both boolean case split and
   649 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   650 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   651 
   652 * HOL: simplification no longer dives into case-expressions: only the
   653 selector expression is simplified, but not the remaining arms; to
   654 enable full simplification of case-expressions for datatype t, you may
   655 remove t.weak_case_cong from the simpset, either globally (Delcongs
   656 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   657 
   658 * HOL/recdef: the recursion equations generated by 'recdef' for
   659 function 'f' are now called f.simps instead of f.rules; if all
   660 termination conditions are proved automatically, these simplification
   661 rules are added to the simpset, as in primrec; rules may be named
   662 individually as well, resulting in a separate list of theorems for
   663 each equation;
   664 
   665 * HOL/While is a new theory that provides a while-combinator. It
   666 permits the definition of tail-recursive functions without the
   667 provision of a termination measure. The latter is necessary once the
   668 invariant proof rule for while is applied.
   669 
   670 * HOL: new (overloaded) notation for the set of elements below/above
   671 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   672 
   673 * HOL: theorems impI, allI, ballI bound as "strip";
   674 
   675 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   676 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   677 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   678 
   679 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   680 
   681 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   682 main HOL, but was unused);
   683 
   684 * HOL: fewer consts declared as global (e.g. have to refer to
   685 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   686 
   687 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   688 in case of overlap with user translations (e.g. judgements over
   689 tuples); (note that the underlying logical represenation is still
   690 bogus);
   691 
   692 
   693 *** ZF ***
   694 
   695 * ZF: simplification automatically cancels common terms in arithmetic
   696 expressions over nat and int;
   697 
   698 * ZF: new treatment of nat to minimize type-checking: all operators
   699 coerce their operands to a natural number using the function natify,
   700 making the algebraic laws unconditional;
   701 
   702 * ZF: as above, for int: operators coerce their operands to an integer
   703 using the function intify;
   704 
   705 * ZF: the integer library now contains many of the usual laws for the
   706 orderings, including $<=, and monotonicity laws for $+ and $*;
   707 
   708 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   709 simplification;
   710 
   711 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   712 to the simplifier and classical reasoner simultaneously;
   713 
   714 
   715 *** General ***
   716 
   717 * Provers: blast_tac now handles actual object-logic rules as
   718 assumptions; note that auto_tac uses blast_tac internally as well;
   719 
   720 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   721 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   722 
   723 * Provers: delrules now handles destruct rules as well (no longer need
   724 explicit make_elim);
   725 
   726 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   727   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   728 use instead the strong form,
   729   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   730 in HOL, FOL and ZF the function cla_make_elim will create such rules
   731 from destruct-rules;
   732 
   733 * Provers: Simplifier.easy_setup provides a fast path to basic
   734 Simplifier setup for new object-logics;
   735 
   736 * Pure: AST translation rules no longer require constant head on LHS;
   737 
   738 * Pure: improved name spaces: ambiguous output is qualified; support
   739 for hiding of names;
   740 
   741 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   742 XSYMBOL_HOME; no longer need to do manual configuration in most
   743 situations;
   744 
   745 * system: compression of ML heaps images may now be controlled via -c
   746 option of isabelle and isatool usedir (currently only observed by
   747 Poly/ML);
   748 
   749 * system: isatool installfonts may handle X-Symbol fonts as well (very
   750 useful for remote X11);
   751 
   752 * system: provide TAGS file for Isabelle sources;
   753 
   754 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   755 order;
   756 
   757 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   758 timing flag supersedes proof_timing and Toplevel.trace;
   759 
   760 * ML: new combinators |>> and |>>> for incremental transformations
   761 with secondary results (e.g. certain theory extensions):
   762 
   763 * ML: PureThy.add_defs gets additional argument to indicate potential
   764 overloading (usually false);
   765 
   766 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   767 results;
   768 
   769 
   770 
   771 New in Isabelle99 (October 1999)
   772 --------------------------------
   773 
   774 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   775 
   776 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   777 are no longer simplified.  (This allows the simplifier to unfold recursive
   778 functional programs.)  To restore the old behaviour, declare
   779 
   780     Delcongs [if_weak_cong];
   781 
   782 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   783 complement;
   784 
   785 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   786 
   787 * HOL/datatype: mutual_induct_tac no longer exists --
   788   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   789 
   790 * HOL/typedef: fixed type inference for representing set; type
   791 arguments now have to occur explicitly on the rhs as type constraints;
   792 
   793 * ZF: The con_defs part of an inductive definition may no longer refer
   794 to constants declared in the same theory;
   795 
   796 * HOL, ZF: the function mk_cases, generated by the inductive
   797 definition package, has lost an argument.  To simplify its result, it
   798 uses the default simpset instead of a supplied list of theorems.
   799 
   800 * HOL/List: the constructors of type list are now Nil and Cons;
   801 
   802 * Simplifier: the type of the infix ML functions
   803         setSSolver addSSolver setSolver addSolver
   804 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   805 for packaging solvers. A solver is created via
   806         mk_solver: string -> (thm list -> int -> tactic) -> solver
   807 where the string argument is only a comment.
   808 
   809 
   810 *** Proof tools ***
   811 
   812 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   813 decision procedure for linear arithmetic. Currently it is used for
   814 types `nat', `int', and `real' in HOL (see below); it can, should and
   815 will be instantiated for other types and logics as well.
   816 
   817 * The simplifier now accepts rewrite rules with flexible heads, eg
   818      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   819   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   820   matching.
   821 
   822 
   823 *** General ***
   824 
   825 * New Isabelle/Isar subsystem provides an alternative to traditional
   826 tactical theorem proving; together with the ProofGeneral/isar user
   827 interface it offers an interactive environment for developing human
   828 readable proof documents (Isar == Intelligible semi-automated
   829 reasoning); for further information see isatool doc isar-ref,
   830 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   831 
   832 * improved and simplified presentation of theories: better HTML markup
   833 (including colors), graph views in several sizes; isatool usedir now
   834 provides a proper interface for user theories (via -P option); actual
   835 document preparation based on (PDF)LaTeX is available as well (for
   836 new-style theories only); see isatool doc system for more information;
   837 
   838 * native support for Proof General, both for classic Isabelle and
   839 Isabelle/Isar;
   840 
   841 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   842 using the graph browser tool;
   843 
   844 * Isabelle manuals now also available as PDF;
   845 
   846 * theory loader rewritten from scratch (may not be fully
   847 bug-compatible); old loadpath variable has been replaced by show_path,
   848 add_path, del_path, reset_path functions; new operations such as
   849 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   850 isatool doc ref);
   851 
   852 * improved isatool install: option -k creates KDE application icon,
   853 option -p DIR installs standalone binaries;
   854 
   855 * added ML_PLATFORM setting (useful for cross-platform installations);
   856 more robust handling of platform specific ML images for SML/NJ;
   857 
   858 * the settings environment is now statically scoped, i.e. it is never
   859 created again in sub-processes invoked from isabelle, isatool, or
   860 Isabelle;
   861 
   862 * path element specification '~~' refers to '$ISABELLE_HOME';
   863 
   864 * in locales, the "assumes" and "defines" parts may be omitted if
   865 empty;
   866 
   867 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   868 long arrows);
   869 
   870 * new print_mode "HTML";
   871 
   872 * new flag show_tags controls display of tags of theorems (which are
   873 basically just comments that may be attached by some tools);
   874 
   875 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   876 mode and goal output format:
   877 
   878 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   879 244c244
   880 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   881 ---
   882 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   883 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   884 181c181
   885 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   886 ---
   887 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   888 
   889 * function bind_thms stores lists of theorems (cf. bind_thm);
   890 
   891 * new shorthand tactics ftac, eatac, datac, fatac;
   892 
   893 * qed (and friends) now accept "" as result name; in that case the
   894 theorem is not stored, but proper checks and presentation of the
   895 result still apply;
   896 
   897 * theorem database now also indexes constants "Trueprop", "all",
   898 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   899 
   900 
   901 *** HOL ***
   902 
   903 ** HOL arithmetic **
   904 
   905 * There are now decision procedures for linear arithmetic over nat and
   906 int:
   907 
   908 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   909 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   910 are treated as atomic; subformulae not involving type `nat' or `int'
   911 are ignored; quantified subformulae are ignored unless they are
   912 positive universal or negative existential. The tactic has to be
   913 invoked by hand and can be a little bit slow. In particular, the
   914 running time is exponential in the number of occurrences of `min' and
   915 `max', and `-' on `nat'.
   916 
   917 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   918 (negated) (in)equalities among the premises and the conclusion into
   919 account (i.e. no compound formulae) and does not know about `min' and
   920 `max', and `-' on `nat'. It is fast and is used automatically by the
   921 simplifier.
   922 
   923 NB: At the moment, these decision procedures do not cope with mixed
   924 nat/int formulae where the two parts interact, such as `m < n ==>
   925 int(m) < int(n)'.
   926 
   927 * HOL/Numeral provides a generic theory of numerals (encoded
   928 efficiently as bit strings); setup for types nat/int/real is in place;
   929 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   930 int, existing theories and proof scripts may require a few additional
   931 type constraints;
   932 
   933 * integer division and remainder can now be performed on constant
   934 arguments;
   935 
   936 * many properties of integer multiplication, division and remainder
   937 are now available;
   938 
   939 * An interface to the Stanford Validity Checker (SVC) is available through the
   940 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   941 are proved automatically.  SVC must be installed separately, and its results
   942 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   943 invocation of the underlying oracle).  For SVC see
   944   http://verify.stanford.edu/SVC
   945 
   946 * IsaMakefile: the HOL-Real target now builds an actual image;
   947 
   948 
   949 ** HOL misc **
   950 
   951 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   952 (in Isabelle/Isar) -- by Gertrud Bauer;
   953 
   954 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   955 analysis for assembly languages with subtypes;
   956 
   957 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   958 -- avoids syntactic ambiguities and treats state, transition, and
   959 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   960 changed syntax and (many) tactics;
   961 
   962 * HOL/inductive: Now also handles more general introduction rules such
   963   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   964   theorems are now maintained within the theory (maintained via the
   965   "mono" attribute);
   966 
   967 * HOL/datatype: Now also handles arbitrarily branching datatypes
   968   (using function types) such as
   969 
   970   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   971 
   972 * HOL/record: record_simproc (part of the default simpset) takes care
   973 of selectors applied to updated records; record_split_tac is no longer
   974 part of the default claset; update_defs may now be removed from the
   975 simpset in many cases; COMPATIBILITY: old behavior achieved by
   976 
   977   claset_ref () := claset() addSWrapper record_split_wrapper;
   978   Delsimprocs [record_simproc]
   979 
   980 * HOL/typedef: fixed type inference for representing set; type
   981 arguments now have to occur explicitly on the rhs as type constraints;
   982 
   983 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   984 names rather than an ML expression;
   985 
   986 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   987 supplied later.  Program schemes can be defined, such as
   988     "While B C s = (if B s then While B C (C s) else s)"
   989 where the well-founded relation can be chosen after B and C have been given.
   990 
   991 * HOL/List: the constructors of type list are now Nil and Cons;
   992 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   993 course, ML tools referring to List.list.op # etc. have to be adapted;
   994 
   995 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   996 disabled by default; run isabelle with option -m HOL to get back to
   997 the original Gordon/HOL-style output;
   998 
   999 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1000 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1001 
  1002 * HOL basic syntax simplified (more orthogonal): all variants of
  1003 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1004 Eps operator is provided as well: "SOME x. P[x]";
  1005 
  1006 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1007 
  1008 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1009 thus available for user theories;
  1010 
  1011 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1012 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1013 time;
  1014 
  1015 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1016 several times and then mp;
  1017 
  1018 
  1019 *** LK ***
  1020 
  1021 * the notation <<...>> is now available as a notation for sequences of
  1022 formulas;
  1023 
  1024 * the simplifier is now installed
  1025 
  1026 * the axiom system has been generalized (thanks to Soren Heilmann)
  1027 
  1028 * the classical reasoner now has a default rule database
  1029 
  1030 
  1031 *** ZF ***
  1032 
  1033 * new primrec section allows primitive recursive functions to be given
  1034 directly (as in HOL) over datatypes and the natural numbers;
  1035 
  1036 * new tactics induct_tac and exhaust_tac for induction (or case
  1037 analysis) over datatypes and the natural numbers;
  1038 
  1039 * the datatype declaration of type T now defines the recursor T_rec;
  1040 
  1041 * simplification automatically does freeness reasoning for datatype
  1042 constructors;
  1043 
  1044 * automatic type-inference, with AddTCs command to insert new
  1045 type-checking rules;
  1046 
  1047 * datatype introduction rules are now added as Safe Introduction rules
  1048 to the claset;
  1049 
  1050 * the syntax "if P then x else y" is now available in addition to
  1051 if(P,x,y);
  1052 
  1053 
  1054 *** Internal programming interfaces ***
  1055 
  1056 * tuned simplifier trace output; new flag debug_simp;
  1057 
  1058 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1059 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1060 
  1061 * AxClass.axclass_tac lost the theory argument;
  1062 
  1063 * tuned current_goals_markers semantics: begin / end goal avoids
  1064 printing empty lines;
  1065 
  1066 * removed prs and prs_fn hook, which was broken because it did not
  1067 include \n in its semantics, forcing writeln to add one
  1068 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1069 string -> unit if you really want to output text without newline;
  1070 
  1071 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1072 plain output, interface builders may have to enable 'isabelle_font'
  1073 mode to get Isabelle font glyphs as before;
  1074 
  1075 * refined token_translation interface; INCOMPATIBILITY: output length
  1076 now of type real instead of int;
  1077 
  1078 * theory loader actions may be traced via new ThyInfo.add_hook
  1079 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1080 your own database of information attached to *whole* theories -- as
  1081 opposed to intra-theory data slots offered via TheoryDataFun;
  1082 
  1083 * proper handling of dangling sort hypotheses (at last!);
  1084 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1085 extra sort hypotheses that can be witnessed from the type signature;
  1086 the force_strip_shyps flag is gone, any remaining shyps are simply
  1087 left in the theorem (with a warning issued by strip_shyps_warning);
  1088 
  1089 
  1090 
  1091 New in Isabelle98-1 (October 1998)
  1092 ----------------------------------
  1093 
  1094 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1095 
  1096 * several changes of automated proof tools;
  1097 
  1098 * HOL: major changes to the inductive and datatype packages, including
  1099 some minor incompatibilities of theory syntax;
  1100 
  1101 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1102 called `inj_on';
  1103 
  1104 * HOL: removed duplicate thms in Arith:
  1105   less_imp_add_less  should be replaced by  trans_less_add1
  1106   le_imp_add_le      should be replaced by  trans_le_add1
  1107 
  1108 * HOL: unary minus is now overloaded (new type constraints may be
  1109 required);
  1110 
  1111 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1112 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1113 now taken as an integer constant.
  1114 
  1115 * Pure: ML function 'theory_of' renamed to 'theory';
  1116 
  1117 
  1118 *** Proof tools ***
  1119 
  1120 * Simplifier:
  1121   1. Asm_full_simp_tac is now more aggressive.
  1122      1. It will sometimes reorient premises if that increases their power to
  1123         simplify.
  1124      2. It does no longer proceed strictly from left to right but may also
  1125         rotate premises to achieve further simplification.
  1126      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1127      old Asm_full_simp_tac in that it does not rotate premises.
  1128   2. The simplifier now knows a little bit about nat-arithmetic.
  1129 
  1130 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1131 allows for selected deletion of wrappers, by introduction of names for
  1132 wrapper functionals.  This implies that addbefore, addSbefore,
  1133 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1134 and that adding two tactics with the same name overwrites the first
  1135 one (emitting a warning).
  1136   type wrapper = (int -> tactic) -> (int -> tactic)
  1137   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1138   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1139   delWrapper, delSWrapper: claset *  string            -> claset
  1140   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1141 
  1142 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1143 semantics; addbefore now affects only the unsafe part of step_tac
  1144 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1145 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1146 by Force_tac;
  1147 
  1148 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1149 compWrapper; added safe wrapper (and access functions for it);
  1150 
  1151 * HOL/split_all_tac is now much faster and fails if there is nothing
  1152 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1153 and the names of the automatically generated variables have changed.
  1154 split_all_tac has moved within claset() from unsafe wrappers to safe
  1155 wrappers, which means that !!-bound variables are split much more
  1156 aggressively, and safe_tac and clarify_tac now split such variables.
  1157 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1158 Note: the same holds for record_split_tac, which does the job of
  1159 split_all_tac for record fields.
  1160 
  1161 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1162 permanently to the default simpset using Addsplits just like
  1163 Addsimps. They can be removed via Delsplits just like
  1164 Delsimps. Lower-case versions are also available.
  1165 
  1166 * HOL/Simplifier: The rule split_if is now part of the default
  1167 simpset. This means that the simplifier will eliminate all occurrences
  1168 of if-then-else in the conclusion of a goal. To prevent this, you can
  1169 either remove split_if completely from the default simpset by
  1170 `Delsplits [split_if]' or remove it in a specific call of the
  1171 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1172 other case splitting rules to/from the default simpset: every datatype
  1173 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1174 t is the name of the datatype).
  1175 
  1176 * Classical reasoner / Simplifier combination: new force_tac (and
  1177 derivatives Force_tac, force) combines rewriting and classical
  1178 reasoning (and whatever other tools) similarly to auto_tac, but is
  1179 aimed to solve the given subgoal completely.
  1180 
  1181 
  1182 *** General ***
  1183 
  1184 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1185 and `goalw': the theory is no longer needed as an explicit argument -
  1186 the current theory context is used; assumptions are no longer returned
  1187 at the ML-level unless one of them starts with ==> or !!; it is
  1188 recommended to convert to these new commands using isatool fixgoal
  1189 (backup your sources first!);
  1190 
  1191 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1192 the current theory context, and 'theory' to lookup stored theories;
  1193 
  1194 * new theory section 'locale' for declaring constants, assumptions and
  1195 definitions that have local scope;
  1196 
  1197 * new theory section 'nonterminals' for purely syntactic types;
  1198 
  1199 * new theory section 'setup' for generic ML setup functions
  1200 (e.g. package initialization);
  1201 
  1202 * the distribution now includes Isabelle icons: see
  1203 lib/logo/isabelle-{small,tiny}.xpm;
  1204 
  1205 * isatool install - install binaries with absolute references to
  1206 ISABELLE_HOME/bin;
  1207 
  1208 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1209 
  1210 * print mode 'emacs' reserved for Isamode;
  1211 
  1212 * support multiple print (ast) translations per constant name;
  1213 
  1214 * theorems involving oracles are now printed with a suffixed [!];
  1215 
  1216 
  1217 *** HOL ***
  1218 
  1219 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1220 
  1221 * HOL/inductive package reorganized and improved: now supports mutual
  1222 definitions such as
  1223 
  1224   inductive EVEN ODD
  1225     intrs
  1226       null "0 : EVEN"
  1227       oddI "n : EVEN ==> Suc n : ODD"
  1228       evenI "n : ODD ==> Suc n : EVEN"
  1229 
  1230 new theorem list "elims" contains an elimination rule for each of the
  1231 recursive sets; inductive definitions now handle disjunctive premises
  1232 correctly (also ZF);
  1233 
  1234 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1235 "mutual_induct" no longer exists - the induction rule is always
  1236 contained in "induct";
  1237 
  1238 
  1239 * HOL/datatype package re-implemented and greatly improved: now
  1240 supports mutually recursive datatypes such as
  1241 
  1242   datatype
  1243     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1244             | SUM ('a aexp) ('a aexp)
  1245             | DIFF ('a aexp) ('a aexp)
  1246             | NUM 'a
  1247   and
  1248     'a bexp = LESS ('a aexp) ('a aexp)
  1249             | AND ('a bexp) ('a bexp)
  1250             | OR ('a bexp) ('a bexp)
  1251 
  1252 as well as indirectly recursive datatypes such as
  1253 
  1254   datatype
  1255     ('a, 'b) term = Var 'a
  1256                   | App 'b ((('a, 'b) term) list)
  1257 
  1258 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1259 induction on mutually / indirectly recursive datatypes.
  1260 
  1261 Primrec equations are now stored in theory and can be accessed via
  1262 <function_name>.simps.
  1263 
  1264 INCOMPATIBILITIES:
  1265 
  1266   - Theories using datatypes must now have theory Datatype as an
  1267     ancestor.
  1268   - The specific <typename>.induct_tac no longer exists - use the
  1269     generic induct_tac instead.
  1270   - natE has been renamed to nat.exhaust - use exhaust_tac
  1271     instead of res_inst_tac ... natE. Note that the variable
  1272     names in nat.exhaust differ from the names in natE, this
  1273     may cause some "fragile" proofs to fail.
  1274   - The theorems split_<typename>_case and split_<typename>_case_asm
  1275     have been renamed to <typename>.split and <typename>.split_asm.
  1276   - Since default sorts of type variables are now handled correctly,
  1277     some datatype definitions may have to be annotated with explicit
  1278     sort constraints.
  1279   - Primrec definitions no longer require function name and type
  1280     of recursive argument.
  1281 
  1282 Consider using isatool fixdatatype to adapt your theories and proof
  1283 scripts to the new package (backup your sources first!).
  1284 
  1285 
  1286 * HOL/record package: considerably improved implementation; now
  1287 includes concrete syntax for record types, terms, updates; theorems
  1288 for surjective pairing and splitting !!-bound record variables; proof
  1289 support is as follows:
  1290 
  1291   1) standard conversions (selectors or updates applied to record
  1292 constructor terms) are part of the standard simpset;
  1293 
  1294   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1295 made part of standard simpset and claset via addIffs;
  1296 
  1297   3) a tactic for record field splitting (record_split_tac) is part of
  1298 the standard claset (addSWrapper);
  1299 
  1300 To get a better idea about these rules you may retrieve them via
  1301 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1302 the name of your record type.
  1303 
  1304 The split tactic 3) conceptually simplifies by the following rule:
  1305 
  1306   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1307 
  1308 Thus any record variable that is bound by meta-all will automatically
  1309 blow up into some record constructor term, consequently the
  1310 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1311 solve record problems automatically.
  1312 
  1313 
  1314 * reorganized the main HOL image: HOL/Integ and String loaded by
  1315 default; theory Main includes everything;
  1316 
  1317 * automatic simplification of integer sums and comparisons, using cancellation;
  1318 
  1319 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1320 
  1321 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1322 
  1323 * many new identities for unions, intersections, set difference, etc.;
  1324 
  1325 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1326 called split_if, split_split, split_sum_case and split_nat_case (to go
  1327 with add/delsplits);
  1328 
  1329 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1330 (?x::unit) = (); this is made part of the default simpset, which COULD
  1331 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1332 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1333 unit_abs_eta_conv is added in order to counter the effect of
  1334 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1335 %u.f();
  1336 
  1337 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1338 makes more sense);
  1339 
  1340 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1341   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1342   disjointness reasoning but breaking a few old proofs.
  1343 
  1344 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1345 to 'converse' from 'inverse' (for compatibility with ZF and some
  1346 literature);
  1347 
  1348 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1349 the well-founded relation;
  1350 
  1351 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1352     Compl A.  The "Compl" syntax remains available as input syntax for this
  1353     release ONLY.
  1354 
  1355 * HOL/Update: new theory of function updates:
  1356     f(a:=b) == %x. if x=a then b else f x
  1357 may also be iterated as in f(a:=b,c:=d,...);
  1358 
  1359 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1360 
  1361 * HOL/List:
  1362   - new function list_update written xs[i:=v] that updates the i-th
  1363     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1364   - new function `upt' written [i..j(] which generates the list
  1365     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1366     bound write [i..j], which is a shorthand for [i..j+1(].
  1367   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1368 
  1369 * HOL/Arith:
  1370   - removed 'pred' (predecessor) function;
  1371   - generalized some theorems about n-1;
  1372   - many new laws about "div" and "mod";
  1373   - new laws about greatest common divisors (see theory ex/Primes);
  1374 
  1375 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1376 instead of "inverse";
  1377 
  1378 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1379   of the multiset ordering;
  1380 
  1381 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1382   (not included by default);
  1383 
  1384 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1385 
  1386 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1387   programs, i.e. different program variables may have different types.
  1388 
  1389 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1390   [previously, this check worked only if the rewrite rule was unconditional]
  1391   Now rew can involve either definitions or equalities (either == or =).
  1392 
  1393 
  1394 *** ZF ***
  1395 
  1396 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1397   only the theorems proved on ZF.ML;
  1398 
  1399 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1400   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1401   disjointness reasoning but breaking a few old proofs.
  1402 
  1403 * ZF/Update: new theory of function updates
  1404     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1405   may also be iterated as in f(a:=b,c:=d,...);
  1406 
  1407 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1408 
  1409 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1410   [previously, this check worked only if the rewrite rule was unconditional]
  1411   Now rew can involve either definitions or equalities (either == or =).
  1412 
  1413 * case_tac provided for compatibility with HOL
  1414     (like the old excluded_middle_tac, but with subgoals swapped)
  1415 
  1416 
  1417 *** Internal programming interfaces ***
  1418 
  1419 * Pure: several new basic modules made available for general use, see
  1420 also src/Pure/README;
  1421 
  1422 * improved the theory data mechanism to support encapsulation (data
  1423 kind name replaced by private Object.kind, acting as authorization
  1424 key); new type-safe user interface via functor TheoryDataFun; generic
  1425 print_data function becomes basically useless;
  1426 
  1427 * removed global_names compatibility flag -- all theory declarations
  1428 are qualified by default;
  1429 
  1430 * module Pure/Syntax now offers quote / antiquote translation
  1431 functions (useful for Hoare logic etc. with implicit dependencies);
  1432 see HOL/ex/Antiquote for an example use;
  1433 
  1434 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1435 cterm -> thm;
  1436 
  1437 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1438 subgoal;
  1439 
  1440 * Display.print_goals function moved to Locale.print_goals;
  1441 
  1442 * standard print function for goals supports current_goals_markers
  1443 variable for marking begin of proof, end of proof, start of goal; the
  1444 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1445 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1446 for example;
  1447 
  1448 
  1449 
  1450 New in Isabelle98 (January 1998)
  1451 --------------------------------
  1452 
  1453 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1454 
  1455 * changed lexical syntax of terms / types: dots made part of long
  1456 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1457 
  1458 * simpset (and claset) reference variable replaced by functions
  1459 simpset / simpset_ref;
  1460 
  1461 * no longer supports theory aliases (via merge) and non-trivial
  1462 implicit merge of thms' signatures;
  1463 
  1464 * most internal names of constants changed due to qualified names;
  1465 
  1466 * changed Pure/Sequence interface (see Pure/seq.ML);
  1467 
  1468 
  1469 *** General Changes ***
  1470 
  1471 * hierachically structured name spaces (for consts, types, axms, thms
  1472 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1473 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1474 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1475 long_names for fully qualified output names; NOTE: ML programs
  1476 (special tactics, packages etc.) referring to internal names may have
  1477 to be adapted to cope with fully qualified names; in case of severe
  1478 backward campatibility problems try setting 'global_names' at compile
  1479 time to have enrything declared within a flat name space; one may also
  1480 fine tune name declarations in theories via the 'global' and 'local'
  1481 section;
  1482 
  1483 * reimplemented the implicit simpset and claset using the new anytype
  1484 data filed in signatures; references simpset:simpset ref etc. are
  1485 replaced by functions simpset:unit->simpset and
  1486 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1487 to patch your ML files accordingly;
  1488 
  1489 * HTML output now includes theory graph data for display with Java
  1490 applet or isatool browser; data generated automatically via isatool
  1491 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1492 
  1493 * defs may now be conditional; improved rewrite_goals_tac to handle
  1494 conditional equations;
  1495 
  1496 * defs now admits additional type arguments, using TYPE('a) syntax;
  1497 
  1498 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1499 creates a new theory node; implicit merge of thms' signatures is
  1500 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1501 transfer:theory->thm->thm in (rare) cases;
  1502 
  1503 * improved handling of draft signatures / theories; draft thms (and
  1504 ctyps, cterms) are automatically promoted to real ones;
  1505 
  1506 * slightly changed interfaces for oracles: admit many per theory, named
  1507 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1508 
  1509 * print_goals: optional output of const types (set show_consts and
  1510 show_types);
  1511 
  1512 * improved output of warnings (###) and errors (***);
  1513 
  1514 * subgoal_tac displays a warning if the new subgoal has type variables;
  1515 
  1516 * removed old README and Makefiles;
  1517 
  1518 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1519 
  1520 * removed obsolete init_pps and init_database;
  1521 
  1522 * deleted the obsolete tactical STATE, which was declared by
  1523     fun STATE tacfun st = tacfun st st;
  1524 
  1525 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1526 (which abbreviates $HOME);
  1527 
  1528 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1529 use isatool fixseq to adapt your ML programs (this works for fully
  1530 qualified references to the Sequence structure only!);
  1531 
  1532 * use_thy no longer requires writable current directory; it always
  1533 reloads .ML *and* .thy file, if either one is out of date;
  1534 
  1535 
  1536 *** Classical Reasoner ***
  1537 
  1538 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1539 tactics that use classical reasoning to simplify a subgoal without
  1540 splitting it into several subgoals;
  1541 
  1542 * Safe_tac: like safe_tac but uses the default claset;
  1543 
  1544 
  1545 *** Simplifier ***
  1546 
  1547 * added simplification meta rules:
  1548     (asm_)(full_)simplify: simpset -> thm -> thm;
  1549 
  1550 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1551 logics (again);
  1552 
  1553 * added prems argument to simplification procedures;
  1554 
  1555 * HOL, FOL, ZF: added infix function `addsplits':
  1556   instead of `<simpset> setloop (split_tac <thms>)'
  1557   you can simply write `<simpset> addsplits <thms>'
  1558 
  1559 
  1560 *** Syntax ***
  1561 
  1562 * TYPE('a) syntax for type reflection terms;
  1563 
  1564 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1565 
  1566 * pretty printer: changed order of mixfix annotation preference (again!);
  1567 
  1568 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1569 
  1570 
  1571 *** HOL ***
  1572 
  1573 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1574   with `addloop' of the simplifier to faciliate case splitting in premises.
  1575 
  1576 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1577 
  1578 * HOL/Auth: new protocol proofs including some for the Internet
  1579   protocol TLS;
  1580 
  1581 * HOL/Map: new theory of `maps' a la VDM;
  1582 
  1583 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1584 cancelling out common nat summands from =, <, <= (in)equalities, or
  1585 differences; simplification procedures nat_cancel_factor for
  1586 cancelling common factor from =, <, <= (in)equalities over natural
  1587 sums; nat_cancel contains both kinds of procedures, it is installed by
  1588 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1589 
  1590 * HOL/simplifier: terms of the form
  1591   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1592   are rewritten to
  1593   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1594   and those of the form
  1595   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1596   are rewritten to
  1597   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1598 
  1599 * HOL/datatype
  1600   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1601 
  1602   P(t_case f1 ... fn x) =
  1603      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1604         ...
  1605        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1606      )
  1607 
  1608   and a theorem `split_t_case_asm' of the form
  1609 
  1610   P(t_case f1 ... fn x) =
  1611     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1612         ...
  1613        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1614      )
  1615   which can be added to a simpset via `addsplits'. The existing theorems
  1616   expand_list_case and expand_option_case have been renamed to
  1617   split_list_case and split_option_case.
  1618 
  1619 * HOL/Arithmetic:
  1620   - `pred n' is automatically converted to `n-1'.
  1621     Users are strongly encouraged not to use `pred' any longer,
  1622     because it will disappear altogether at some point.
  1623   - Users are strongly encouraged to write "0 < n" rather than
  1624     "n ~= 0". Theorems and proof tools have been modified towards this
  1625     `standard'.
  1626 
  1627 * HOL/Lists:
  1628   the function "set_of_list" has been renamed "set" (and its theorems too);
  1629   the function "nth" now takes its arguments in the reverse order and
  1630   has acquired the infix notation "!" as in "xs!n".
  1631 
  1632 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1633 
  1634 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1635   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1636 
  1637 * HOL/record: extensible records with schematic structural subtyping
  1638 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1639 still lacks various theorems and concrete record syntax;
  1640 
  1641 
  1642 *** HOLCF ***
  1643 
  1644 * removed "axioms" and "generated by" sections;
  1645 
  1646 * replaced "ops" section by extended "consts" section, which is capable of
  1647   handling the continuous function space "->" directly;
  1648 
  1649 * domain package:
  1650   . proves theorems immediately and stores them in the theory,
  1651   . creates hierachical name space,
  1652   . now uses normal mixfix annotations (instead of cinfix...),
  1653   . minor changes to some names and values (for consistency),
  1654   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1655   . separator between mutual domain defs: changed "," to "and",
  1656   . improved handling of sort constraints;  now they have to
  1657     appear on the left-hand side of the equations only;
  1658 
  1659 * fixed LAM <x,y,zs>.b syntax;
  1660 
  1661 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1662 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1663 
  1664 
  1665 *** FOL and ZF ***
  1666 
  1667 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1668   with `addloop' of the simplifier to faciliate case splitting in premises.
  1669 
  1670 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1671 in HOL, they strip ALL and --> from proved theorems;
  1672 
  1673 
  1674 
  1675 New in Isabelle94-8 (May 1997)
  1676 ------------------------------
  1677 
  1678 *** General Changes ***
  1679 
  1680 * new utilities to build / run / maintain Isabelle etc. (in parts
  1681 still somewhat experimental); old Makefiles etc. still functional;
  1682 
  1683 * new 'Isabelle System Manual';
  1684 
  1685 * INSTALL text, together with ./configure and ./build scripts;
  1686 
  1687 * reimplemented type inference for greater efficiency, better error
  1688 messages and clean internal interface;
  1689 
  1690 * prlim command for dealing with lots of subgoals (an easier way of
  1691 setting goals_limit);
  1692 
  1693 
  1694 *** Syntax ***
  1695 
  1696 * supports alternative (named) syntax tables (parser and pretty
  1697 printer); internal interface is provided by add_modesyntax(_i);
  1698 
  1699 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1700 be used in conjunction with the Isabelle symbol font; uses the
  1701 "symbols" syntax table;
  1702 
  1703 * added token_translation interface (may translate name tokens in
  1704 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1705 the current print_mode); IMPORTANT: user print translation functions
  1706 are responsible for marking newly introduced bounds
  1707 (Syntax.mark_boundT);
  1708 
  1709 * token translations for modes "xterm" and "xterm_color" that display
  1710 names in bold, underline etc. or colors (which requires a color
  1711 version of xterm);
  1712 
  1713 * infixes may now be declared with names independent of their syntax;
  1714 
  1715 * added typed_print_translation (like print_translation, but may
  1716 access type of constant);
  1717 
  1718 
  1719 *** Classical Reasoner ***
  1720 
  1721 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1722 some limitations.  Blast_tac...
  1723   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1724   + ignores elimination rules that don't have the correct format
  1725         (the conclusion MUST be a formula variable)
  1726   + ignores types, which can make HOL proofs fail
  1727   + rules must not require higher-order unification, e.g. apply_type in ZF
  1728     [message "Function Var's argument not a bound variable" relates to this]
  1729   + its proof strategy is more general but can actually be slower
  1730 
  1731 * substitution with equality assumptions no longer permutes other
  1732 assumptions;
  1733 
  1734 * minor changes in semantics of addafter (now called addaltern); renamed
  1735 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1736 (and access functions for it);
  1737 
  1738 * improved combination of classical reasoner and simplifier:
  1739   + functions for handling clasimpsets
  1740   + improvement of addss: now the simplifier is called _after_ the
  1741     safe steps.
  1742   + safe variant of addss called addSss: uses safe simplifications
  1743     _during_ the safe steps. It is more complete as it allows multiple
  1744     instantiations of unknowns (e.g. with slow_tac).
  1745 
  1746 *** Simplifier ***
  1747 
  1748 * added interface for simplification procedures (functions that
  1749 produce *proven* rewrite rules on the fly, depending on current
  1750 redex);
  1751 
  1752 * ordering on terms as parameter (used for ordered rewriting);
  1753 
  1754 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1755 
  1756 * the solver is now split into a safe and an unsafe part.
  1757 This should be invisible for the normal user, except that the
  1758 functions setsolver and addsolver have been renamed to setSolver and
  1759 addSolver; added safe_asm_full_simp_tac;
  1760 
  1761 
  1762 *** HOL ***
  1763 
  1764 * a generic induction tactic `induct_tac' which works for all datatypes and
  1765 also for type `nat';
  1766 
  1767 * a generic case distinction tactic `exhaust_tac' which works for all
  1768 datatypes and also for type `nat';
  1769 
  1770 * each datatype comes with a function `size';
  1771 
  1772 * patterns in case expressions allow tuple patterns as arguments to
  1773 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1774 
  1775 * primrec now also works with type nat;
  1776 
  1777 * recdef: a new declaration form, allows general recursive functions to be
  1778 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1779 
  1780 * the constant for negation has been renamed from "not" to "Not" to
  1781 harmonize with FOL, ZF, LK, etc.;
  1782 
  1783 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1784 infinite lists;
  1785 
  1786 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1787 
  1788 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1789 problems in commutative rings, using axiomatic type classes for + and *;
  1790 
  1791 * more examples in HOL/MiniML and HOL/Auth;
  1792 
  1793 * more default rewrite rules for quantifiers, union/intersection;
  1794 
  1795 * a new constant `arbitrary == @x.False';
  1796 
  1797 * HOLCF/IOA replaces old HOL/IOA;
  1798 
  1799 * HOLCF changes: derived all rules and arities
  1800   + axiomatic type classes instead of classes
  1801   + typedef instead of faking type definitions
  1802   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1803   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1804   + eliminated the types void, one, tr
  1805   + use unit lift and bool lift (with translations) instead of one and tr
  1806   + eliminated blift from Lift3.thy (use Def instead of blift)
  1807   all eliminated rules are derived as theorems --> no visible changes ;
  1808 
  1809 
  1810 *** ZF ***
  1811 
  1812 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1813 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1814 as ZF_cs addSIs [equalityI];
  1815 
  1816 
  1817 
  1818 New in Isabelle94-7 (November 96)
  1819 ---------------------------------
  1820 
  1821 * allowing negative levels (as offsets) in prlev and choplev;
  1822 
  1823 * super-linear speedup for large simplifications;
  1824 
  1825 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1826 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1827 FAIL); can suppress it using the command Delsimps (ex_simps @
  1828 all_simps); De Morgan laws are also now included, by default;
  1829 
  1830 * improved printing of ==>  :  ~:
  1831 
  1832 * new object-logic "Sequents" adds linear logic, while replacing LK
  1833 and Modal (thanks to Sara Kalvala);
  1834 
  1835 * HOL/Auth: correctness proofs for authentication protocols;
  1836 
  1837 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1838 examples on HOL/Auth);
  1839 
  1840 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1841 the rewriter and classical reasoner simultaneously;
  1842 
  1843 * function uresult no longer returns theorems in "standard" format;
  1844 regain previous version by: val uresult = standard o uresult;
  1845 
  1846 
  1847 
  1848 New in Isabelle94-6
  1849 -------------------
  1850 
  1851 * oracles -- these establish an interface between Isabelle and trusted
  1852 external reasoners, which may deliver results as theorems;
  1853 
  1854 * proof objects (in particular record all uses of oracles);
  1855 
  1856 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1857 
  1858 * "constdefs" section in theory files;
  1859 
  1860 * "primrec" section (HOL) no longer requires names;
  1861 
  1862 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1863 
  1864 
  1865 
  1866 New in Isabelle94-5
  1867 -------------------
  1868 
  1869 * reduced space requirements;
  1870 
  1871 * automatic HTML generation from theories;
  1872 
  1873 * theory files no longer require "..." (quotes) around most types;
  1874 
  1875 * new examples, including two proofs of the Church-Rosser theorem;
  1876 
  1877 * non-curried (1994) version of HOL is no longer distributed;
  1878 
  1879 
  1880 
  1881 New in Isabelle94-4
  1882 -------------------
  1883 
  1884 * greatly reduced space requirements;
  1885 
  1886 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1887 
  1888 * searchable theorem database (see the section "Retrieving theorems" on
  1889 page 8 of the Reference Manual);
  1890 
  1891 * new examples, including Grabczewski's monumental case study of the
  1892 Axiom of Choice;
  1893 
  1894 * The previous version of HOL renamed to Old_HOL;
  1895 
  1896 * The new version of HOL (previously called CHOL) uses a curried syntax
  1897 for functions.  Application looks like f a b instead of f(a,b);
  1898 
  1899 * Mutually recursive inductive definitions finally work in HOL;
  1900 
  1901 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1902 translates to the operator "split";
  1903 
  1904 
  1905 
  1906 New in Isabelle94-3
  1907 -------------------
  1908 
  1909 * new infix operator, addss, allowing the classical reasoner to
  1910 perform simplification at each step of its search.  Example:
  1911         fast_tac (cs addss ss)
  1912 
  1913 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1914 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1915 look like (a,b) instead of <a,b>;
  1916 
  1917 * PLEASE NOTE: CHOL will eventually replace HOL!
  1918 
  1919 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1920 It translates to the operator "split".  A new theory of integers is available;
  1921 
  1922 * In ZF, integer numerals now denote two's-complement binary integers.
  1923 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1924 
  1925 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1926 of the Axiom of Choice;
  1927 
  1928 
  1929 
  1930 New in Isabelle94-2
  1931 -------------------
  1932 
  1933 * Significantly faster resolution;
  1934 
  1935 * the different sections in a .thy file can now be mixed and repeated
  1936 freely;
  1937 
  1938 * Database of theorems for FOL, HOL and ZF.  New
  1939 commands including qed, qed_goal and bind_thm store theorems in the database.
  1940 
  1941 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1942 a given theory (thms_of), or find out what theory a theorem was proved in
  1943 (theory_of_thm);
  1944 
  1945 * Bugs fixed in the inductive definition and datatype packages;
  1946 
  1947 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1948 and HOL_dup_cs obsolete;
  1949 
  1950 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1951 have been removed;
  1952 
  1953 * Simpler definition of function space in ZF;
  1954 
  1955 * new results about cardinal and ordinal arithmetic in ZF;
  1956 
  1957 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1958 types;
  1959 
  1960 
  1961 $Id$