NEWS
author wenzelm
Thu Oct 25 22:41:07 2001 +0200 (2001-10-25)
changeset 11936 fef099613354
parent 11933 acfea249b03c
child 11937 2a2b1182a23b
permissions -rw-r--r--
* Provers: 'simplified' attribute may refer to explicit rules instead
of full simplifier context; 'iff' attribute handles conditional rules;
* HOL/record:
- provides cases/induct rules for use with corresponding Isar methods;
- old "make" and "make_scheme" operation removed -- INCOMPATIBILITY;
- new derived operations "make" (for adding fields of current
record), "extend" to promote fixed record to record scheme, and
"truncate" for the reverse; cf. theorems "derived_defs", which are
*not* declared as simp by default;
- 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 over
    58 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
    59 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
    60 
    61 * Provers: 'simplified' attribute may refer to explicit rules instead
    62 of full simplifier context; 'iff' attribute handles conditional rules;
    63 
    64 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
    65 
    66 * HOL: 'recdef' now fails on unfinished automated proofs, use
    67 "(permissive)" option to recover old behavior;
    68 
    69 * HOL: 'inductive' no longer features separate (collective) attributes
    70 for 'intros' (was found too confusing);
    71 
    72 
    73 
    74 *** HOL ***
    75 
    76 * HOL: moved over to sane numeral syntax; the new policy is as
    77 follows:
    78 
    79   - 0 and 1 are polymorphic constants, which are defined on any
    80   numeric type (nat, int, real etc.);
    81 
    82   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
    83   binary representation internally;
    84 
    85   - type nat has special constructor Suc, and generally prefers Suc 0
    86   over 1::nat and Suc (Suc 0) over 2::nat;
    87 
    88 This change may cause significant INCOMPATIBILITIES; here are some
    89 hints on converting existing sources:
    90 
    91   - due to the new "num" token, "-0" and "-1" etc. are now atomic
    92   entities, so expressions involving "-" (unary or binary minus) need
    93   to be spaced properly;
    94 
    95   - existing occurrences of "1" may need to be constraint "1::nat" or
    96   even replaced by Suc 0; similar for old "2";
    97 
    98   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
    99 
   100   - remove all special provisions on numerals in proofs;
   101 
   102 * HOL/record:
   103   - provides cases/induct rules for use with corresponding Isar methods;
   104   - old "make" and "make_scheme" operation removed -- INCOMPATIBILITY;
   105   - new derived operations "make" (for adding fields of current
   106     record), "extend" to promote fixed record to record scheme, and
   107     "truncate" for the reverse; cf. theorems "derived_defs", which are
   108     *not* declared as simp by default;
   109   - internal definitions directly based on a light-weight abstract
   110     theory of product types over typedef rather than datatype;
   111 
   112 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   113 
   114 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   115 (beware of argument permutation!);
   116 
   117 * HOL: linorder_less_split superseded by linorder_cases;
   118 
   119 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   120 to peripheral theory "Hilbert_Choice";
   121 
   122 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   123 in this (rare) case use:
   124 
   125   delSWrapper "split_all_tac"
   126   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   127 
   128 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   129 MAY FAIL;
   130 
   131 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   132 Isabelle's type classes, ^ on functions and relations has too general
   133 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   134 necessary to attach explicit type constraints;
   135 
   136 * HOL: syntax translations now work properly with numerals and records
   137 expressions;
   138 
   139 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   140 Florian Kammüller;
   141 
   142 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   143 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   144 renamed "Product_Type.unit";
   145 
   146 
   147 *** ZF ***
   148 
   149 * ZF: the integer library now covers quotients and remainders, with
   150 many laws relating division to addition, multiplication, etc.;
   151 
   152 
   153 *** General ***
   154 
   155 * kernel: meta-level proof terms (by Stefan Berghofer), see also ref
   156 manual;
   157 
   158 * classical: renamed addaltern to addafter, addSaltern to addSafter;
   159 
   160 * clasimp: ``iff'' declarations now handle conditional rules as well;
   161 
   162 * syntax: new token syntax "num" for plain numerals (without "#" of
   163 "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now separate
   164 tokens, so expressions involving minus need to be spaced properly;
   165 
   166 * syntax: support non-oriented infixes;
   167 
   168 * syntax: print modes "type_brackets" and "no_type_brackets" control
   169 output of nested => (types); the default behavior is "type_brackets";
   170 
   171 * syntax: builtin parse translation for "_constify" turns valued
   172 tokens into AST constants;
   173 
   174 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   175 
   176 * system: Proof General keywords specification is now part of the
   177 Isabelle distribution (see etc/isar-keywords.el);
   178 
   179 * system: smart selection of Isabelle process versus Isabelle
   180 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   181 run both "isabelle" and "Isabelle" even if file names are badly
   182 damaged (executable inspects the case of the first letter of its own
   183 name); added separate "isabelle-process" and "isabelle-interface";
   184 
   185 
   186 
   187 New in Isabelle99-2 (February 2001)
   188 -----------------------------------
   189 
   190 *** Overview of INCOMPATIBILITIES ***
   191 
   192 * HOL: please note that theories in the Library and elsewhere often use the
   193 new-style (Isar) format; to refer to their theorems in an ML script you must
   194 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   195 
   196 * HOL: inductive package no longer splits induction rule aggressively,
   197 but only as far as specified by the introductions given; the old
   198 format may be recovered via ML function complete_split_rule or attribute
   199 'split_rule (complete)';
   200 
   201 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   202 gfp_Tarski to gfp_unfold;
   203 
   204 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   205 
   206 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   207 relation); infix "^^" has been renamed "``"; infix "``" has been
   208 renamed "`"; "univalent" has been renamed "single_valued";
   209 
   210 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   211 operation;
   212 
   213 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   214 
   215 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   216 
   217 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   218 consequence, it is no longer monotonic wrt. the local goal context
   219 (which is now passed through the inductive cases);
   220 
   221 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   222 \<gg> to \<ggreater>;
   223 
   224 
   225 *** Document preparation ***
   226 
   227 * \isabellestyle{NAME} selects version of Isabelle output (currently
   228 available: are "it" for near math-mode best-style output, "sl" for
   229 slanted text style, and "tt" for plain type-writer; if no
   230 \isabellestyle command is given, output is according to slanted
   231 type-writer);
   232 
   233 * support sub/super scripts (for single symbols only), input syntax is
   234 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   235 
   236 * some more standard symbols; see Appendix A of the system manual for
   237 the complete list of symbols defined in isabellesym.sty;
   238 
   239 * improved isabelle style files; more abstract symbol implementation
   240 (should now use \isamath{...} and \isatext{...} in custom symbol
   241 definitions);
   242 
   243 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   244 state; Note that presentation of goal states does not conform to
   245 actual human-readable proof documents.  Please do not include goal
   246 states into document output unless you really know what you are doing!
   247 
   248 * proper indentation of antiquoted output with proportional LaTeX
   249 fonts;
   250 
   251 * no_document ML operator temporarily disables LaTeX document
   252 generation;
   253 
   254 * isatool unsymbolize tunes sources for plain ASCII communication;
   255 
   256 
   257 *** Isar ***
   258 
   259 * Pure: Isar now suffers initial goal statements to contain unbound
   260 schematic variables (this does not conform to actual readable proof
   261 documents, due to unpredictable outcome and non-compositional proof
   262 checking); users who know what they are doing may use schematic goals
   263 for Prolog-style synthesis of proven results;
   264 
   265 * Pure: assumption method (an implicit finishing) now handles actual
   266 rules as well;
   267 
   268 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   269 initial goal, declare "that" only as Pure intro (only for single
   270 steps); the "that" rule assumption may now be involved in implicit
   271 finishing, thus ".." becomes a feasible for trivial obtains;
   272 
   273 * Pure: default proof step now includes 'intro_classes'; thus trivial
   274 instance proofs may be performed by "..";
   275 
   276 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   277 statements as well;
   278 
   279 * Pure: more robust selection of calculational rules;
   280 
   281 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   282 rule (as well as the assumption rule);
   283 
   284 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   285 lemmas, using the graph browser tool;
   286 
   287 * Pure: predict failure of "show" in interactive mode;
   288 
   289 * Pure: 'thms_containing' now takes actual terms as arguments;
   290 
   291 * HOL: improved method 'induct' --- now handles non-atomic goals
   292 (potential INCOMPATIBILITY); tuned error handling;
   293 
   294 * HOL: cases and induct rules now provide explicit hints about the
   295 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   296 any remaining facts are inserted into the goal verbatim;
   297 
   298 * HOL: local contexts (aka cases) may now contain term bindings as
   299 well; the 'cases' and 'induct' methods new provide a ?case binding for
   300 the result to be shown in each case;
   301 
   302 * HOL: added 'recdef_tc' command;
   303 
   304 * isatool convert assists in eliminating legacy ML scripts;
   305 
   306 
   307 *** HOL ***
   308 
   309 * HOL/Library: a collection of generic theories to be used together
   310 with main HOL; the theory loader path already includes this directory
   311 by default; the following existing theories have been moved here:
   312 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   313 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   314 
   315 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   316 modelling and verification task performed in Isabelle/HOL +
   317 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   318 
   319 * HOL/Algebra: special summation operator SUM no longer exists, it has
   320 been replaced by setsum; infix 'assoc' now has priority 50 (like
   321 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   322 'domain', this makes the theory consistent with mathematical
   323 literature;
   324 
   325 * HOL basics: added overloaded operations "inverse" and "divide"
   326 (infix "/"), syntax for generic "abs" operation, generic summation
   327 operator \<Sum>;
   328 
   329 * HOL/typedef: simplified package, provide more useful rules (see also
   330 HOL/subset.thy);
   331 
   332 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   333 now expressed as a proper nested rule (old-style tactic scripts may
   334 require atomize_strip_tac to cope with non-atomic premises);
   335 
   336 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   337 to "split_conv" (old name still available for compatibility);
   338 
   339 * HOL: improved concrete syntax for strings (e.g. allows translation
   340 rules with string literals);
   341 
   342 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   343 and Fleuriot's mechanization of analysis;
   344 
   345 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   346 
   347 
   348 *** CTT ***
   349 
   350 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   351 "lam" is displayed as TWO lambda-symbols
   352 
   353 * CTT: theory Main now available, containing everything (that is, Bool
   354 and Arith);
   355 
   356 
   357 *** General ***
   358 
   359 * Pure: the Simplifier has been implemented properly as a derived rule
   360 outside of the actual kernel (at last!); the overall performance
   361 penalty in practical applications is about 50%, while reliability of
   362 the Isabelle inference kernel has been greatly improved;
   363 
   364 * print modes "brackets" and "no_brackets" control output of nested =>
   365 (types) and ==> (props); the default behaviour is "brackets";
   366 
   367 * Provers: fast_tac (and friends) now handle actual object-logic rules
   368 as assumptions as well;
   369 
   370 * system: support Poly/ML 4.0;
   371 
   372 * system: isatool install handles KDE version 1 or 2;
   373 
   374 
   375 
   376 New in Isabelle99-1 (October 2000)
   377 ----------------------------------
   378 
   379 *** Overview of INCOMPATIBILITIES ***
   380 
   381 * HOL: simplification of natural numbers is much changed; to partly
   382 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   383 issue the following ML commands:
   384 
   385   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   386   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   387 
   388 * HOL: simplification no longer dives into case-expressions; this is
   389 controlled by "t.weak_case_cong" for each datatype t;
   390 
   391 * HOL: nat_less_induct renamed to less_induct;
   392 
   393 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   394 fixsome to patch .thy and .ML sources automatically;
   395 
   396   select_equality  -> some_equality
   397   select_eq_Ex     -> some_eq_ex
   398   selectI2EX       -> someI2_ex
   399   selectI2         -> someI2
   400   selectI          -> someI
   401   select1_equality -> some1_equality
   402   Eps_sym_eq       -> some_sym_eq_trivial
   403   Eps_eq           -> some_eq_trivial
   404 
   405 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   406 
   407 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   408 instead);
   409 
   410 * HOL: the recursion equations generated by 'recdef' are now called
   411 f.simps instead of f.rules;
   412 
   413 * HOL: qed_spec_mp now also handles bounded ALL as well;
   414 
   415 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   416 sometimes be needed;
   417 
   418 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   419 
   420 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   421 
   422 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   423 product is now "<*>" instead of "Times"; the lexicographic product is
   424 now "<*lex*>" instead of "**";
   425 
   426 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   427 of main HOL, but was unused); better use HOL's datatype package;
   428 
   429 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   430 the old syntax may be recovered as follows:
   431 
   432   syntax (symbols)
   433     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   434       (infixl "\\<oplus>" 100)
   435 
   436 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   437 
   438 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   439 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   440 internally;
   441 
   442 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   443 changed from A/r to A//r;
   444 
   445 * ZF: new treatment of arithmetic (nat & int) may break some old
   446 proofs;
   447 
   448 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   449 rulify -> rule_format, elimify -> elim_format, ...);
   450 
   451 * Isar/Provers: intro/elim/dest attributes changed; renamed
   452 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   453 should have to change intro!! to intro? only); replaced "delrule" by
   454 "rule del";
   455 
   456 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   457 
   458 * Provers: strengthened force_tac by using new first_best_tac;
   459 
   460 * LaTeX document preparation: several changes of isabelle.sty (see
   461 lib/texinputs);
   462 
   463 
   464 *** Document preparation ***
   465 
   466 * formal comments (text blocks etc.) in new-style theories may now
   467 contain antiquotations of thm/prop/term/typ/text to be presented
   468 according to latex print mode; concrete syntax is like this:
   469 @{term[show_types] "f(x) = a + x"};
   470 
   471 * isatool mkdir provides easy setup of Isabelle session directories,
   472 including proper document sources;
   473 
   474 * generated LaTeX sources are now deleted after successful run
   475 (isatool document -c); may retain a copy somewhere else via -D option
   476 of isatool usedir;
   477 
   478 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   479 style files, achieving self-contained LaTeX sources and simplifying
   480 LaTeX debugging;
   481 
   482 * old-style theories now produce (crude) LaTeX output as well;
   483 
   484 * browser info session directories are now self-contained (may be put
   485 on WWW server seperately); improved graphs of nested sessions; removed
   486 graph for 'all sessions';
   487 
   488 * several improvements in isabelle style files; \isabellestyle{it}
   489 produces fake math mode output; \isamarkupheader is now \section by
   490 default; see lib/texinputs/isabelle.sty etc.;
   491 
   492 
   493 *** Isar ***
   494 
   495 * Isar/Pure: local results and corresponding term bindings are now
   496 subject to Hindley-Milner polymorphism (similar to ML); this
   497 accommodates incremental type-inference very nicely;
   498 
   499 * Isar/Pure: new derived language element 'obtain' supports
   500 generalized existence reasoning;
   501 
   502 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   503 support accumulation of results, without applying any rules yet;
   504 useful to collect intermediate results without explicit name
   505 references, and for use with transitivity rules with more than 2
   506 premises;
   507 
   508 * Isar/Pure: scalable support for case-analysis type proofs: new
   509 'case' language element refers to local contexts symbolically, as
   510 produced by certain proof methods; internally, case names are attached
   511 to theorems as "tags";
   512 
   513 * Isar/Pure: theory command 'hide' removes declarations from
   514 class/type/const name spaces;
   515 
   516 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   517 indicate potential overloading;
   518 
   519 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   520 
   521 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   522 "{a,b,c}" instead of {a,b,c};
   523 
   524 * Isar/Pure now provides its own version of intro/elim/dest
   525 attributes; useful for building new logics, but beware of confusion
   526 with the version in Provers/classical;
   527 
   528 * Isar/Pure: the local context of (non-atomic) goals is provided via
   529 case name 'antecedent';
   530 
   531 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   532 to the current context is now done automatically);
   533 
   534 * Isar/Pure: theory command 'method_setup' provides a simple interface
   535 for definining proof methods in ML;
   536 
   537 * Isar/Provers: intro/elim/dest attributes changed; renamed
   538 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   539 most cases, one should have to change intro!! to intro? only);
   540 replaced "delrule" by "rule del";
   541 
   542 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   543 'symmetric' attribute (the latter supercedes [RS sym]);
   544 
   545 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   546 method modifier); 'simp' method: 'only:' modifier removes loopers as
   547 well (including splits);
   548 
   549 * Isar/Provers: Simplifier and Classical methods now support all kind
   550 of modifiers used in the past, including 'cong', 'iff', etc.
   551 
   552 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   553 of Simplifier and Classical reasoner);
   554 
   555 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   556 now support named cases; major packages (inductive, datatype, primrec,
   557 recdef) support case names and properly name parameters;
   558 
   559 * Isar/HOL: new transitivity rules for substitution in inequalities --
   560 monotonicity conditions are extracted to be proven at end of
   561 calculations;
   562 
   563 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   564 method anyway;
   565 
   566 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   567 split_if split_if_asm; datatype package provides theorems foo.splits =
   568 foo.split foo.split_asm for each datatype;
   569 
   570 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   571 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   572 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   573 use "(cases (simplified))" method in proper proof texts);
   574 
   575 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   576 
   577 * Isar: names of theorems etc. may be natural numbers as well;
   578 
   579 * Isar: 'pr' command: optional arguments for goals_limit and
   580 ProofContext.prems_limit; no longer prints theory contexts, but only
   581 proof states;
   582 
   583 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   584 additional print modes to be specified; e.g. "pr(latex)" will print
   585 proof state according to the Isabelle LaTeX style;
   586 
   587 * Isar: improved support for emulating tactic scripts, including proof
   588 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   589 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   590 (for HOL datatypes);
   591 
   592 * Isar: simplified (more robust) goal selection of proof methods: 1st
   593 goal, all goals, or explicit goal specifier (tactic emulation); thus
   594 'proof method scripts' have to be in depth-first order;
   595 
   596 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   597 
   598 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   599 should instead use individual commands for printing items
   600 (print_commands, print_methods etc.);
   601 
   602 * Isar: added 'nothing' --- the empty list of theorems;
   603 
   604 
   605 *** HOL ***
   606 
   607 * HOL/MicroJava: formalization of a fragment of Java, together with a
   608 corresponding virtual machine and a specification of its bytecode
   609 verifier and a lightweight bytecode verifier, including proofs of
   610 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   611 Cornelia Pusch (see also the homepage of project Bali at
   612 http://isabelle.in.tum.de/Bali/);
   613 
   614 * HOL/Algebra: new theory of rings and univariate polynomials, by
   615 Clemens Ballarin;
   616 
   617 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   618 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   619 Rasmussen;
   620 
   621 * HOL/Lattice: fundamental concepts of lattice theory and order
   622 structures, including duals, properties of bounds versus algebraic
   623 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   624 Theorem for complete lattices etc.; may also serve as a demonstration
   625 for abstract algebraic reasoning using axiomatic type classes, and
   626 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   627 
   628 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   629 von Oheimb;
   630 
   631 * HOL/IMPP: extension of IMP with local variables and mutually
   632 recursive procedures, by David von Oheimb;
   633 
   634 * HOL/Lambda: converted into new-style theory and document;
   635 
   636 * HOL/ex/Multiquote: example of multiple nested quotations and
   637 anti-quotations -- basically a generalized version of de-Bruijn
   638 representation; very useful in avoiding lifting of operations;
   639 
   640 * HOL/record: added general record equality rule to simpset; fixed
   641 select-update simplification procedure to handle extended records as
   642 well; admit "r" as field name;
   643 
   644 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   645 other numeric types and also as the identity of groups, rings, etc.;
   646 
   647 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   648 Types nat and int belong to this axclass;
   649 
   650 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   651    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   652    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   653   two terms #m*u and #n*u are replaced by #(m+n)*u
   654     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   655   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   656     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   657 
   658 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   659 powerful prover for predicate logic but knows nothing of clasets; see
   660 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   661 
   662 * HOL: new version of "case_tac" subsumes both boolean case split and
   663 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   664 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   665 
   666 * HOL: simplification no longer dives into case-expressions: only the
   667 selector expression is simplified, but not the remaining arms; to
   668 enable full simplification of case-expressions for datatype t, you may
   669 remove t.weak_case_cong from the simpset, either globally (Delcongs
   670 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   671 
   672 * HOL/recdef: the recursion equations generated by 'recdef' for
   673 function 'f' are now called f.simps instead of f.rules; if all
   674 termination conditions are proved automatically, these simplification
   675 rules are added to the simpset, as in primrec; rules may be named
   676 individually as well, resulting in a separate list of theorems for
   677 each equation;
   678 
   679 * HOL/While is a new theory that provides a while-combinator. It
   680 permits the definition of tail-recursive functions without the
   681 provision of a termination measure. The latter is necessary once the
   682 invariant proof rule for while is applied.
   683 
   684 * HOL: new (overloaded) notation for the set of elements below/above
   685 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   686 
   687 * HOL: theorems impI, allI, ballI bound as "strip";
   688 
   689 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   690 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   691 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   692 
   693 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   694 
   695 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   696 main HOL, but was unused);
   697 
   698 * HOL: fewer consts declared as global (e.g. have to refer to
   699 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   700 
   701 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   702 in case of overlap with user translations (e.g. judgements over
   703 tuples); (note that the underlying logical represenation is still
   704 bogus);
   705 
   706 
   707 *** ZF ***
   708 
   709 * ZF: simplification automatically cancels common terms in arithmetic
   710 expressions over nat and int;
   711 
   712 * ZF: new treatment of nat to minimize type-checking: all operators
   713 coerce their operands to a natural number using the function natify,
   714 making the algebraic laws unconditional;
   715 
   716 * ZF: as above, for int: operators coerce their operands to an integer
   717 using the function intify;
   718 
   719 * ZF: the integer library now contains many of the usual laws for the
   720 orderings, including $<=, and monotonicity laws for $+ and $*;
   721 
   722 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   723 simplification;
   724 
   725 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   726 to the simplifier and classical reasoner simultaneously;
   727 
   728 
   729 *** General ***
   730 
   731 * Provers: blast_tac now handles actual object-logic rules as
   732 assumptions; note that auto_tac uses blast_tac internally as well;
   733 
   734 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   735 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   736 
   737 * Provers: delrules now handles destruct rules as well (no longer need
   738 explicit make_elim);
   739 
   740 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   741   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   742 use instead the strong form,
   743   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   744 in HOL, FOL and ZF the function cla_make_elim will create such rules
   745 from destruct-rules;
   746 
   747 * Provers: Simplifier.easy_setup provides a fast path to basic
   748 Simplifier setup for new object-logics;
   749 
   750 * Pure: AST translation rules no longer require constant head on LHS;
   751 
   752 * Pure: improved name spaces: ambiguous output is qualified; support
   753 for hiding of names;
   754 
   755 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   756 XSYMBOL_HOME; no longer need to do manual configuration in most
   757 situations;
   758 
   759 * system: compression of ML heaps images may now be controlled via -c
   760 option of isabelle and isatool usedir (currently only observed by
   761 Poly/ML);
   762 
   763 * system: isatool installfonts may handle X-Symbol fonts as well (very
   764 useful for remote X11);
   765 
   766 * system: provide TAGS file for Isabelle sources;
   767 
   768 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   769 order;
   770 
   771 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   772 timing flag supersedes proof_timing and Toplevel.trace;
   773 
   774 * ML: new combinators |>> and |>>> for incremental transformations
   775 with secondary results (e.g. certain theory extensions):
   776 
   777 * ML: PureThy.add_defs gets additional argument to indicate potential
   778 overloading (usually false);
   779 
   780 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   781 results;
   782 
   783 
   784 
   785 New in Isabelle99 (October 1999)
   786 --------------------------------
   787 
   788 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   789 
   790 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   791 are no longer simplified.  (This allows the simplifier to unfold recursive
   792 functional programs.)  To restore the old behaviour, declare
   793 
   794     Delcongs [if_weak_cong];
   795 
   796 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   797 complement;
   798 
   799 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   800 
   801 * HOL/datatype: mutual_induct_tac no longer exists --
   802   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   803 
   804 * HOL/typedef: fixed type inference for representing set; type
   805 arguments now have to occur explicitly on the rhs as type constraints;
   806 
   807 * ZF: The con_defs part of an inductive definition may no longer refer
   808 to constants declared in the same theory;
   809 
   810 * HOL, ZF: the function mk_cases, generated by the inductive
   811 definition package, has lost an argument.  To simplify its result, it
   812 uses the default simpset instead of a supplied list of theorems.
   813 
   814 * HOL/List: the constructors of type list are now Nil and Cons;
   815 
   816 * Simplifier: the type of the infix ML functions
   817         setSSolver addSSolver setSolver addSolver
   818 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   819 for packaging solvers. A solver is created via
   820         mk_solver: string -> (thm list -> int -> tactic) -> solver
   821 where the string argument is only a comment.
   822 
   823 
   824 *** Proof tools ***
   825 
   826 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   827 decision procedure for linear arithmetic. Currently it is used for
   828 types `nat', `int', and `real' in HOL (see below); it can, should and
   829 will be instantiated for other types and logics as well.
   830 
   831 * The simplifier now accepts rewrite rules with flexible heads, eg
   832      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   833   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   834   matching.
   835 
   836 
   837 *** General ***
   838 
   839 * New Isabelle/Isar subsystem provides an alternative to traditional
   840 tactical theorem proving; together with the ProofGeneral/isar user
   841 interface it offers an interactive environment for developing human
   842 readable proof documents (Isar == Intelligible semi-automated
   843 reasoning); for further information see isatool doc isar-ref,
   844 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   845 
   846 * improved and simplified presentation of theories: better HTML markup
   847 (including colors), graph views in several sizes; isatool usedir now
   848 provides a proper interface for user theories (via -P option); actual
   849 document preparation based on (PDF)LaTeX is available as well (for
   850 new-style theories only); see isatool doc system for more information;
   851 
   852 * native support for Proof General, both for classic Isabelle and
   853 Isabelle/Isar;
   854 
   855 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   856 using the graph browser tool;
   857 
   858 * Isabelle manuals now also available as PDF;
   859 
   860 * theory loader rewritten from scratch (may not be fully
   861 bug-compatible); old loadpath variable has been replaced by show_path,
   862 add_path, del_path, reset_path functions; new operations such as
   863 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   864 isatool doc ref);
   865 
   866 * improved isatool install: option -k creates KDE application icon,
   867 option -p DIR installs standalone binaries;
   868 
   869 * added ML_PLATFORM setting (useful for cross-platform installations);
   870 more robust handling of platform specific ML images for SML/NJ;
   871 
   872 * the settings environment is now statically scoped, i.e. it is never
   873 created again in sub-processes invoked from isabelle, isatool, or
   874 Isabelle;
   875 
   876 * path element specification '~~' refers to '$ISABELLE_HOME';
   877 
   878 * in locales, the "assumes" and "defines" parts may be omitted if
   879 empty;
   880 
   881 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   882 long arrows);
   883 
   884 * new print_mode "HTML";
   885 
   886 * new flag show_tags controls display of tags of theorems (which are
   887 basically just comments that may be attached by some tools);
   888 
   889 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   890 mode and goal output format:
   891 
   892 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   893 244c244
   894 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   895 ---
   896 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   897 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   898 181c181
   899 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   900 ---
   901 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   902 
   903 * function bind_thms stores lists of theorems (cf. bind_thm);
   904 
   905 * new shorthand tactics ftac, eatac, datac, fatac;
   906 
   907 * qed (and friends) now accept "" as result name; in that case the
   908 theorem is not stored, but proper checks and presentation of the
   909 result still apply;
   910 
   911 * theorem database now also indexes constants "Trueprop", "all",
   912 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   913 
   914 
   915 *** HOL ***
   916 
   917 ** HOL arithmetic **
   918 
   919 * There are now decision procedures for linear arithmetic over nat and
   920 int:
   921 
   922 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   923 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   924 are treated as atomic; subformulae not involving type `nat' or `int'
   925 are ignored; quantified subformulae are ignored unless they are
   926 positive universal or negative existential. The tactic has to be
   927 invoked by hand and can be a little bit slow. In particular, the
   928 running time is exponential in the number of occurrences of `min' and
   929 `max', and `-' on `nat'.
   930 
   931 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   932 (negated) (in)equalities among the premises and the conclusion into
   933 account (i.e. no compound formulae) and does not know about `min' and
   934 `max', and `-' on `nat'. It is fast and is used automatically by the
   935 simplifier.
   936 
   937 NB: At the moment, these decision procedures do not cope with mixed
   938 nat/int formulae where the two parts interact, such as `m < n ==>
   939 int(m) < int(n)'.
   940 
   941 * HOL/Numeral provides a generic theory of numerals (encoded
   942 efficiently as bit strings); setup for types nat/int/real is in place;
   943 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   944 int, existing theories and proof scripts may require a few additional
   945 type constraints;
   946 
   947 * integer division and remainder can now be performed on constant
   948 arguments;
   949 
   950 * many properties of integer multiplication, division and remainder
   951 are now available;
   952 
   953 * An interface to the Stanford Validity Checker (SVC) is available through the
   954 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   955 are proved automatically.  SVC must be installed separately, and its results
   956 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   957 invocation of the underlying oracle).  For SVC see
   958   http://verify.stanford.edu/SVC
   959 
   960 * IsaMakefile: the HOL-Real target now builds an actual image;
   961 
   962 
   963 ** HOL misc **
   964 
   965 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   966 (in Isabelle/Isar) -- by Gertrud Bauer;
   967 
   968 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   969 analysis for assembly languages with subtypes;
   970 
   971 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   972 -- avoids syntactic ambiguities and treats state, transition, and
   973 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   974 changed syntax and (many) tactics;
   975 
   976 * HOL/inductive: Now also handles more general introduction rules such
   977   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   978   theorems are now maintained within the theory (maintained via the
   979   "mono" attribute);
   980 
   981 * HOL/datatype: Now also handles arbitrarily branching datatypes
   982   (using function types) such as
   983 
   984   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   985 
   986 * HOL/record: record_simproc (part of the default simpset) takes care
   987 of selectors applied to updated records; record_split_tac is no longer
   988 part of the default claset; update_defs may now be removed from the
   989 simpset in many cases; COMPATIBILITY: old behavior achieved by
   990 
   991   claset_ref () := claset() addSWrapper record_split_wrapper;
   992   Delsimprocs [record_simproc]
   993 
   994 * HOL/typedef: fixed type inference for representing set; type
   995 arguments now have to occur explicitly on the rhs as type constraints;
   996 
   997 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   998 names rather than an ML expression;
   999 
  1000 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1001 supplied later.  Program schemes can be defined, such as
  1002     "While B C s = (if B s then While B C (C s) else s)"
  1003 where the well-founded relation can be chosen after B and C have been given.
  1004 
  1005 * HOL/List: the constructors of type list are now Nil and Cons;
  1006 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1007 course, ML tools referring to List.list.op # etc. have to be adapted;
  1008 
  1009 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1010 disabled by default; run isabelle with option -m HOL to get back to
  1011 the original Gordon/HOL-style output;
  1012 
  1013 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1014 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1015 
  1016 * HOL basic syntax simplified (more orthogonal): all variants of
  1017 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1018 Eps operator is provided as well: "SOME x. P[x]";
  1019 
  1020 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1021 
  1022 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1023 thus available for user theories;
  1024 
  1025 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1026 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1027 time;
  1028 
  1029 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1030 several times and then mp;
  1031 
  1032 
  1033 *** LK ***
  1034 
  1035 * the notation <<...>> is now available as a notation for sequences of
  1036 formulas;
  1037 
  1038 * the simplifier is now installed
  1039 
  1040 * the axiom system has been generalized (thanks to Soren Heilmann)
  1041 
  1042 * the classical reasoner now has a default rule database
  1043 
  1044 
  1045 *** ZF ***
  1046 
  1047 * new primrec section allows primitive recursive functions to be given
  1048 directly (as in HOL) over datatypes and the natural numbers;
  1049 
  1050 * new tactics induct_tac and exhaust_tac for induction (or case
  1051 analysis) over datatypes and the natural numbers;
  1052 
  1053 * the datatype declaration of type T now defines the recursor T_rec;
  1054 
  1055 * simplification automatically does freeness reasoning for datatype
  1056 constructors;
  1057 
  1058 * automatic type-inference, with AddTCs command to insert new
  1059 type-checking rules;
  1060 
  1061 * datatype introduction rules are now added as Safe Introduction rules
  1062 to the claset;
  1063 
  1064 * the syntax "if P then x else y" is now available in addition to
  1065 if(P,x,y);
  1066 
  1067 
  1068 *** Internal programming interfaces ***
  1069 
  1070 * tuned simplifier trace output; new flag debug_simp;
  1071 
  1072 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1073 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1074 
  1075 * AxClass.axclass_tac lost the theory argument;
  1076 
  1077 * tuned current_goals_markers semantics: begin / end goal avoids
  1078 printing empty lines;
  1079 
  1080 * removed prs and prs_fn hook, which was broken because it did not
  1081 include \n in its semantics, forcing writeln to add one
  1082 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1083 string -> unit if you really want to output text without newline;
  1084 
  1085 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1086 plain output, interface builders may have to enable 'isabelle_font'
  1087 mode to get Isabelle font glyphs as before;
  1088 
  1089 * refined token_translation interface; INCOMPATIBILITY: output length
  1090 now of type real instead of int;
  1091 
  1092 * theory loader actions may be traced via new ThyInfo.add_hook
  1093 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1094 your own database of information attached to *whole* theories -- as
  1095 opposed to intra-theory data slots offered via TheoryDataFun;
  1096 
  1097 * proper handling of dangling sort hypotheses (at last!);
  1098 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1099 extra sort hypotheses that can be witnessed from the type signature;
  1100 the force_strip_shyps flag is gone, any remaining shyps are simply
  1101 left in the theorem (with a warning issued by strip_shyps_warning);
  1102 
  1103 
  1104 
  1105 New in Isabelle98-1 (October 1998)
  1106 ----------------------------------
  1107 
  1108 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1109 
  1110 * several changes of automated proof tools;
  1111 
  1112 * HOL: major changes to the inductive and datatype packages, including
  1113 some minor incompatibilities of theory syntax;
  1114 
  1115 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1116 called `inj_on';
  1117 
  1118 * HOL: removed duplicate thms in Arith:
  1119   less_imp_add_less  should be replaced by  trans_less_add1
  1120   le_imp_add_le      should be replaced by  trans_le_add1
  1121 
  1122 * HOL: unary minus is now overloaded (new type constraints may be
  1123 required);
  1124 
  1125 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1126 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1127 now taken as an integer constant.
  1128 
  1129 * Pure: ML function 'theory_of' renamed to 'theory';
  1130 
  1131 
  1132 *** Proof tools ***
  1133 
  1134 * Simplifier:
  1135   1. Asm_full_simp_tac is now more aggressive.
  1136      1. It will sometimes reorient premises if that increases their power to
  1137         simplify.
  1138      2. It does no longer proceed strictly from left to right but may also
  1139         rotate premises to achieve further simplification.
  1140      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1141      old Asm_full_simp_tac in that it does not rotate premises.
  1142   2. The simplifier now knows a little bit about nat-arithmetic.
  1143 
  1144 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1145 allows for selected deletion of wrappers, by introduction of names for
  1146 wrapper functionals.  This implies that addbefore, addSbefore,
  1147 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1148 and that adding two tactics with the same name overwrites the first
  1149 one (emitting a warning).
  1150   type wrapper = (int -> tactic) -> (int -> tactic)
  1151   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1152   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1153   delWrapper, delSWrapper: claset *  string            -> claset
  1154   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1155 
  1156 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1157 semantics; addbefore now affects only the unsafe part of step_tac
  1158 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1159 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1160 by Force_tac;
  1161 
  1162 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1163 compWrapper; added safe wrapper (and access functions for it);
  1164 
  1165 * HOL/split_all_tac is now much faster and fails if there is nothing
  1166 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1167 and the names of the automatically generated variables have changed.
  1168 split_all_tac has moved within claset() from unsafe wrappers to safe
  1169 wrappers, which means that !!-bound variables are split much more
  1170 aggressively, and safe_tac and clarify_tac now split such variables.
  1171 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1172 Note: the same holds for record_split_tac, which does the job of
  1173 split_all_tac for record fields.
  1174 
  1175 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1176 permanently to the default simpset using Addsplits just like
  1177 Addsimps. They can be removed via Delsplits just like
  1178 Delsimps. Lower-case versions are also available.
  1179 
  1180 * HOL/Simplifier: The rule split_if is now part of the default
  1181 simpset. This means that the simplifier will eliminate all occurrences
  1182 of if-then-else in the conclusion of a goal. To prevent this, you can
  1183 either remove split_if completely from the default simpset by
  1184 `Delsplits [split_if]' or remove it in a specific call of the
  1185 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1186 other case splitting rules to/from the default simpset: every datatype
  1187 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1188 t is the name of the datatype).
  1189 
  1190 * Classical reasoner / Simplifier combination: new force_tac (and
  1191 derivatives Force_tac, force) combines rewriting and classical
  1192 reasoning (and whatever other tools) similarly to auto_tac, but is
  1193 aimed to solve the given subgoal completely.
  1194 
  1195 
  1196 *** General ***
  1197 
  1198 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1199 and `goalw': the theory is no longer needed as an explicit argument -
  1200 the current theory context is used; assumptions are no longer returned
  1201 at the ML-level unless one of them starts with ==> or !!; it is
  1202 recommended to convert to these new commands using isatool fixgoal
  1203 (backup your sources first!);
  1204 
  1205 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1206 the current theory context, and 'theory' to lookup stored theories;
  1207 
  1208 * new theory section 'locale' for declaring constants, assumptions and
  1209 definitions that have local scope;
  1210 
  1211 * new theory section 'nonterminals' for purely syntactic types;
  1212 
  1213 * new theory section 'setup' for generic ML setup functions
  1214 (e.g. package initialization);
  1215 
  1216 * the distribution now includes Isabelle icons: see
  1217 lib/logo/isabelle-{small,tiny}.xpm;
  1218 
  1219 * isatool install - install binaries with absolute references to
  1220 ISABELLE_HOME/bin;
  1221 
  1222 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1223 
  1224 * print mode 'emacs' reserved for Isamode;
  1225 
  1226 * support multiple print (ast) translations per constant name;
  1227 
  1228 * theorems involving oracles are now printed with a suffixed [!];
  1229 
  1230 
  1231 *** HOL ***
  1232 
  1233 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1234 
  1235 * HOL/inductive package reorganized and improved: now supports mutual
  1236 definitions such as
  1237 
  1238   inductive EVEN ODD
  1239     intrs
  1240       null "0 : EVEN"
  1241       oddI "n : EVEN ==> Suc n : ODD"
  1242       evenI "n : ODD ==> Suc n : EVEN"
  1243 
  1244 new theorem list "elims" contains an elimination rule for each of the
  1245 recursive sets; inductive definitions now handle disjunctive premises
  1246 correctly (also ZF);
  1247 
  1248 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1249 "mutual_induct" no longer exists - the induction rule is always
  1250 contained in "induct";
  1251 
  1252 
  1253 * HOL/datatype package re-implemented and greatly improved: now
  1254 supports mutually recursive datatypes such as
  1255 
  1256   datatype
  1257     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1258             | SUM ('a aexp) ('a aexp)
  1259             | DIFF ('a aexp) ('a aexp)
  1260             | NUM 'a
  1261   and
  1262     'a bexp = LESS ('a aexp) ('a aexp)
  1263             | AND ('a bexp) ('a bexp)
  1264             | OR ('a bexp) ('a bexp)
  1265 
  1266 as well as indirectly recursive datatypes such as
  1267 
  1268   datatype
  1269     ('a, 'b) term = Var 'a
  1270                   | App 'b ((('a, 'b) term) list)
  1271 
  1272 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1273 induction on mutually / indirectly recursive datatypes.
  1274 
  1275 Primrec equations are now stored in theory and can be accessed via
  1276 <function_name>.simps.
  1277 
  1278 INCOMPATIBILITIES:
  1279 
  1280   - Theories using datatypes must now have theory Datatype as an
  1281     ancestor.
  1282   - The specific <typename>.induct_tac no longer exists - use the
  1283     generic induct_tac instead.
  1284   - natE has been renamed to nat.exhaust - use exhaust_tac
  1285     instead of res_inst_tac ... natE. Note that the variable
  1286     names in nat.exhaust differ from the names in natE, this
  1287     may cause some "fragile" proofs to fail.
  1288   - The theorems split_<typename>_case and split_<typename>_case_asm
  1289     have been renamed to <typename>.split and <typename>.split_asm.
  1290   - Since default sorts of type variables are now handled correctly,
  1291     some datatype definitions may have to be annotated with explicit
  1292     sort constraints.
  1293   - Primrec definitions no longer require function name and type
  1294     of recursive argument.
  1295 
  1296 Consider using isatool fixdatatype to adapt your theories and proof
  1297 scripts to the new package (backup your sources first!).
  1298 
  1299 
  1300 * HOL/record package: considerably improved implementation; now
  1301 includes concrete syntax for record types, terms, updates; theorems
  1302 for surjective pairing and splitting !!-bound record variables; proof
  1303 support is as follows:
  1304 
  1305   1) standard conversions (selectors or updates applied to record
  1306 constructor terms) are part of the standard simpset;
  1307 
  1308   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1309 made part of standard simpset and claset via addIffs;
  1310 
  1311   3) a tactic for record field splitting (record_split_tac) is part of
  1312 the standard claset (addSWrapper);
  1313 
  1314 To get a better idea about these rules you may retrieve them via
  1315 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1316 the name of your record type.
  1317 
  1318 The split tactic 3) conceptually simplifies by the following rule:
  1319 
  1320   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1321 
  1322 Thus any record variable that is bound by meta-all will automatically
  1323 blow up into some record constructor term, consequently the
  1324 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1325 solve record problems automatically.
  1326 
  1327 
  1328 * reorganized the main HOL image: HOL/Integ and String loaded by
  1329 default; theory Main includes everything;
  1330 
  1331 * automatic simplification of integer sums and comparisons, using cancellation;
  1332 
  1333 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1334 
  1335 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1336 
  1337 * many new identities for unions, intersections, set difference, etc.;
  1338 
  1339 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1340 called split_if, split_split, split_sum_case and split_nat_case (to go
  1341 with add/delsplits);
  1342 
  1343 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1344 (?x::unit) = (); this is made part of the default simpset, which COULD
  1345 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1346 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1347 unit_abs_eta_conv is added in order to counter the effect of
  1348 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1349 %u.f();
  1350 
  1351 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1352 makes more sense);
  1353 
  1354 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1355   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1356   disjointness reasoning but breaking a few old proofs.
  1357 
  1358 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1359 to 'converse' from 'inverse' (for compatibility with ZF and some
  1360 literature);
  1361 
  1362 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1363 the well-founded relation;
  1364 
  1365 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1366     Compl A.  The "Compl" syntax remains available as input syntax for this
  1367     release ONLY.
  1368 
  1369 * HOL/Update: new theory of function updates:
  1370     f(a:=b) == %x. if x=a then b else f x
  1371 may also be iterated as in f(a:=b,c:=d,...);
  1372 
  1373 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1374 
  1375 * HOL/List:
  1376   - new function list_update written xs[i:=v] that updates the i-th
  1377     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1378   - new function `upt' written [i..j(] which generates the list
  1379     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1380     bound write [i..j], which is a shorthand for [i..j+1(].
  1381   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1382 
  1383 * HOL/Arith:
  1384   - removed 'pred' (predecessor) function;
  1385   - generalized some theorems about n-1;
  1386   - many new laws about "div" and "mod";
  1387   - new laws about greatest common divisors (see theory ex/Primes);
  1388 
  1389 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1390 instead of "inverse";
  1391 
  1392 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1393   of the multiset ordering;
  1394 
  1395 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1396   (not included by default);
  1397 
  1398 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1399 
  1400 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1401   programs, i.e. different program variables may have different types.
  1402 
  1403 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1404   [previously, this check worked only if the rewrite rule was unconditional]
  1405   Now rew can involve either definitions or equalities (either == or =).
  1406 
  1407 
  1408 *** ZF ***
  1409 
  1410 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1411   only the theorems proved on ZF.ML;
  1412 
  1413 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1414   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1415   disjointness reasoning but breaking a few old proofs.
  1416 
  1417 * ZF/Update: new theory of function updates
  1418     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1419   may also be iterated as in f(a:=b,c:=d,...);
  1420 
  1421 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1422 
  1423 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1424   [previously, this check worked only if the rewrite rule was unconditional]
  1425   Now rew can involve either definitions or equalities (either == or =).
  1426 
  1427 * case_tac provided for compatibility with HOL
  1428     (like the old excluded_middle_tac, but with subgoals swapped)
  1429 
  1430 
  1431 *** Internal programming interfaces ***
  1432 
  1433 * Pure: several new basic modules made available for general use, see
  1434 also src/Pure/README;
  1435 
  1436 * improved the theory data mechanism to support encapsulation (data
  1437 kind name replaced by private Object.kind, acting as authorization
  1438 key); new type-safe user interface via functor TheoryDataFun; generic
  1439 print_data function becomes basically useless;
  1440 
  1441 * removed global_names compatibility flag -- all theory declarations
  1442 are qualified by default;
  1443 
  1444 * module Pure/Syntax now offers quote / antiquote translation
  1445 functions (useful for Hoare logic etc. with implicit dependencies);
  1446 see HOL/ex/Antiquote for an example use;
  1447 
  1448 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1449 cterm -> thm;
  1450 
  1451 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1452 subgoal;
  1453 
  1454 * Display.print_goals function moved to Locale.print_goals;
  1455 
  1456 * standard print function for goals supports current_goals_markers
  1457 variable for marking begin of proof, end of proof, start of goal; the
  1458 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1459 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1460 for example;
  1461 
  1462 
  1463 
  1464 New in Isabelle98 (January 1998)
  1465 --------------------------------
  1466 
  1467 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1468 
  1469 * changed lexical syntax of terms / types: dots made part of long
  1470 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1471 
  1472 * simpset (and claset) reference variable replaced by functions
  1473 simpset / simpset_ref;
  1474 
  1475 * no longer supports theory aliases (via merge) and non-trivial
  1476 implicit merge of thms' signatures;
  1477 
  1478 * most internal names of constants changed due to qualified names;
  1479 
  1480 * changed Pure/Sequence interface (see Pure/seq.ML);
  1481 
  1482 
  1483 *** General Changes ***
  1484 
  1485 * hierachically structured name spaces (for consts, types, axms, thms
  1486 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1487 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1488 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1489 long_names for fully qualified output names; NOTE: ML programs
  1490 (special tactics, packages etc.) referring to internal names may have
  1491 to be adapted to cope with fully qualified names; in case of severe
  1492 backward campatibility problems try setting 'global_names' at compile
  1493 time to have enrything declared within a flat name space; one may also
  1494 fine tune name declarations in theories via the 'global' and 'local'
  1495 section;
  1496 
  1497 * reimplemented the implicit simpset and claset using the new anytype
  1498 data filed in signatures; references simpset:simpset ref etc. are
  1499 replaced by functions simpset:unit->simpset and
  1500 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1501 to patch your ML files accordingly;
  1502 
  1503 * HTML output now includes theory graph data for display with Java
  1504 applet or isatool browser; data generated automatically via isatool
  1505 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1506 
  1507 * defs may now be conditional; improved rewrite_goals_tac to handle
  1508 conditional equations;
  1509 
  1510 * defs now admits additional type arguments, using TYPE('a) syntax;
  1511 
  1512 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1513 creates a new theory node; implicit merge of thms' signatures is
  1514 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1515 transfer:theory->thm->thm in (rare) cases;
  1516 
  1517 * improved handling of draft signatures / theories; draft thms (and
  1518 ctyps, cterms) are automatically promoted to real ones;
  1519 
  1520 * slightly changed interfaces for oracles: admit many per theory, named
  1521 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1522 
  1523 * print_goals: optional output of const types (set show_consts and
  1524 show_types);
  1525 
  1526 * improved output of warnings (###) and errors (***);
  1527 
  1528 * subgoal_tac displays a warning if the new subgoal has type variables;
  1529 
  1530 * removed old README and Makefiles;
  1531 
  1532 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1533 
  1534 * removed obsolete init_pps and init_database;
  1535 
  1536 * deleted the obsolete tactical STATE, which was declared by
  1537     fun STATE tacfun st = tacfun st st;
  1538 
  1539 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1540 (which abbreviates $HOME);
  1541 
  1542 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1543 use isatool fixseq to adapt your ML programs (this works for fully
  1544 qualified references to the Sequence structure only!);
  1545 
  1546 * use_thy no longer requires writable current directory; it always
  1547 reloads .ML *and* .thy file, if either one is out of date;
  1548 
  1549 
  1550 *** Classical Reasoner ***
  1551 
  1552 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1553 tactics that use classical reasoning to simplify a subgoal without
  1554 splitting it into several subgoals;
  1555 
  1556 * Safe_tac: like safe_tac but uses the default claset;
  1557 
  1558 
  1559 *** Simplifier ***
  1560 
  1561 * added simplification meta rules:
  1562     (asm_)(full_)simplify: simpset -> thm -> thm;
  1563 
  1564 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1565 logics (again);
  1566 
  1567 * added prems argument to simplification procedures;
  1568 
  1569 * HOL, FOL, ZF: added infix function `addsplits':
  1570   instead of `<simpset> setloop (split_tac <thms>)'
  1571   you can simply write `<simpset> addsplits <thms>'
  1572 
  1573 
  1574 *** Syntax ***
  1575 
  1576 * TYPE('a) syntax for type reflection terms;
  1577 
  1578 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1579 
  1580 * pretty printer: changed order of mixfix annotation preference (again!);
  1581 
  1582 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1583 
  1584 
  1585 *** HOL ***
  1586 
  1587 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1588   with `addloop' of the simplifier to faciliate case splitting in premises.
  1589 
  1590 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1591 
  1592 * HOL/Auth: new protocol proofs including some for the Internet
  1593   protocol TLS;
  1594 
  1595 * HOL/Map: new theory of `maps' a la VDM;
  1596 
  1597 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1598 cancelling out common nat summands from =, <, <= (in)equalities, or
  1599 differences; simplification procedures nat_cancel_factor for
  1600 cancelling common factor from =, <, <= (in)equalities over natural
  1601 sums; nat_cancel contains both kinds of procedures, it is installed by
  1602 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1603 
  1604 * HOL/simplifier: terms of the form
  1605   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1606   are rewritten to
  1607   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1608   and those of the form
  1609   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1610   are rewritten to
  1611   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1612 
  1613 * HOL/datatype
  1614   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1615 
  1616   P(t_case f1 ... fn x) =
  1617      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1618         ...
  1619        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1620      )
  1621 
  1622   and a theorem `split_t_case_asm' of the form
  1623 
  1624   P(t_case f1 ... fn x) =
  1625     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1626         ...
  1627        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1628      )
  1629   which can be added to a simpset via `addsplits'. The existing theorems
  1630   expand_list_case and expand_option_case have been renamed to
  1631   split_list_case and split_option_case.
  1632 
  1633 * HOL/Arithmetic:
  1634   - `pred n' is automatically converted to `n-1'.
  1635     Users are strongly encouraged not to use `pred' any longer,
  1636     because it will disappear altogether at some point.
  1637   - Users are strongly encouraged to write "0 < n" rather than
  1638     "n ~= 0". Theorems and proof tools have been modified towards this
  1639     `standard'.
  1640 
  1641 * HOL/Lists:
  1642   the function "set_of_list" has been renamed "set" (and its theorems too);
  1643   the function "nth" now takes its arguments in the reverse order and
  1644   has acquired the infix notation "!" as in "xs!n".
  1645 
  1646 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1647 
  1648 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1649   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1650 
  1651 * HOL/record: extensible records with schematic structural subtyping
  1652 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1653 still lacks various theorems and concrete record syntax;
  1654 
  1655 
  1656 *** HOLCF ***
  1657 
  1658 * removed "axioms" and "generated by" sections;
  1659 
  1660 * replaced "ops" section by extended "consts" section, which is capable of
  1661   handling the continuous function space "->" directly;
  1662 
  1663 * domain package:
  1664   . proves theorems immediately and stores them in the theory,
  1665   . creates hierachical name space,
  1666   . now uses normal mixfix annotations (instead of cinfix...),
  1667   . minor changes to some names and values (for consistency),
  1668   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1669   . separator between mutual domain defs: changed "," to "and",
  1670   . improved handling of sort constraints;  now they have to
  1671     appear on the left-hand side of the equations only;
  1672 
  1673 * fixed LAM <x,y,zs>.b syntax;
  1674 
  1675 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1676 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1677 
  1678 
  1679 *** FOL and ZF ***
  1680 
  1681 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1682   with `addloop' of the simplifier to faciliate case splitting in premises.
  1683 
  1684 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1685 in HOL, they strip ALL and --> from proved theorems;
  1686 
  1687 
  1688 
  1689 New in Isabelle94-8 (May 1997)
  1690 ------------------------------
  1691 
  1692 *** General Changes ***
  1693 
  1694 * new utilities to build / run / maintain Isabelle etc. (in parts
  1695 still somewhat experimental); old Makefiles etc. still functional;
  1696 
  1697 * new 'Isabelle System Manual';
  1698 
  1699 * INSTALL text, together with ./configure and ./build scripts;
  1700 
  1701 * reimplemented type inference for greater efficiency, better error
  1702 messages and clean internal interface;
  1703 
  1704 * prlim command for dealing with lots of subgoals (an easier way of
  1705 setting goals_limit);
  1706 
  1707 
  1708 *** Syntax ***
  1709 
  1710 * supports alternative (named) syntax tables (parser and pretty
  1711 printer); internal interface is provided by add_modesyntax(_i);
  1712 
  1713 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1714 be used in conjunction with the Isabelle symbol font; uses the
  1715 "symbols" syntax table;
  1716 
  1717 * added token_translation interface (may translate name tokens in
  1718 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1719 the current print_mode); IMPORTANT: user print translation functions
  1720 are responsible for marking newly introduced bounds
  1721 (Syntax.mark_boundT);
  1722 
  1723 * token translations for modes "xterm" and "xterm_color" that display
  1724 names in bold, underline etc. or colors (which requires a color
  1725 version of xterm);
  1726 
  1727 * infixes may now be declared with names independent of their syntax;
  1728 
  1729 * added typed_print_translation (like print_translation, but may
  1730 access type of constant);
  1731 
  1732 
  1733 *** Classical Reasoner ***
  1734 
  1735 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1736 some limitations.  Blast_tac...
  1737   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1738   + ignores elimination rules that don't have the correct format
  1739         (the conclusion MUST be a formula variable)
  1740   + ignores types, which can make HOL proofs fail
  1741   + rules must not require higher-order unification, e.g. apply_type in ZF
  1742     [message "Function Var's argument not a bound variable" relates to this]
  1743   + its proof strategy is more general but can actually be slower
  1744 
  1745 * substitution with equality assumptions no longer permutes other
  1746 assumptions;
  1747 
  1748 * minor changes in semantics of addafter (now called addaltern); renamed
  1749 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1750 (and access functions for it);
  1751 
  1752 * improved combination of classical reasoner and simplifier:
  1753   + functions for handling clasimpsets
  1754   + improvement of addss: now the simplifier is called _after_ the
  1755     safe steps.
  1756   + safe variant of addss called addSss: uses safe simplifications
  1757     _during_ the safe steps. It is more complete as it allows multiple
  1758     instantiations of unknowns (e.g. with slow_tac).
  1759 
  1760 *** Simplifier ***
  1761 
  1762 * added interface for simplification procedures (functions that
  1763 produce *proven* rewrite rules on the fly, depending on current
  1764 redex);
  1765 
  1766 * ordering on terms as parameter (used for ordered rewriting);
  1767 
  1768 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1769 
  1770 * the solver is now split into a safe and an unsafe part.
  1771 This should be invisible for the normal user, except that the
  1772 functions setsolver and addsolver have been renamed to setSolver and
  1773 addSolver; added safe_asm_full_simp_tac;
  1774 
  1775 
  1776 *** HOL ***
  1777 
  1778 * a generic induction tactic `induct_tac' which works for all datatypes and
  1779 also for type `nat';
  1780 
  1781 * a generic case distinction tactic `exhaust_tac' which works for all
  1782 datatypes and also for type `nat';
  1783 
  1784 * each datatype comes with a function `size';
  1785 
  1786 * patterns in case expressions allow tuple patterns as arguments to
  1787 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1788 
  1789 * primrec now also works with type nat;
  1790 
  1791 * recdef: a new declaration form, allows general recursive functions to be
  1792 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1793 
  1794 * the constant for negation has been renamed from "not" to "Not" to
  1795 harmonize with FOL, ZF, LK, etc.;
  1796 
  1797 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1798 infinite lists;
  1799 
  1800 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1801 
  1802 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1803 problems in commutative rings, using axiomatic type classes for + and *;
  1804 
  1805 * more examples in HOL/MiniML and HOL/Auth;
  1806 
  1807 * more default rewrite rules for quantifiers, union/intersection;
  1808 
  1809 * a new constant `arbitrary == @x.False';
  1810 
  1811 * HOLCF/IOA replaces old HOL/IOA;
  1812 
  1813 * HOLCF changes: derived all rules and arities
  1814   + axiomatic type classes instead of classes
  1815   + typedef instead of faking type definitions
  1816   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1817   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1818   + eliminated the types void, one, tr
  1819   + use unit lift and bool lift (with translations) instead of one and tr
  1820   + eliminated blift from Lift3.thy (use Def instead of blift)
  1821   all eliminated rules are derived as theorems --> no visible changes ;
  1822 
  1823 
  1824 *** ZF ***
  1825 
  1826 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1827 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1828 as ZF_cs addSIs [equalityI];
  1829 
  1830 
  1831 
  1832 New in Isabelle94-7 (November 96)
  1833 ---------------------------------
  1834 
  1835 * allowing negative levels (as offsets) in prlev and choplev;
  1836 
  1837 * super-linear speedup for large simplifications;
  1838 
  1839 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1840 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1841 FAIL); can suppress it using the command Delsimps (ex_simps @
  1842 all_simps); De Morgan laws are also now included, by default;
  1843 
  1844 * improved printing of ==>  :  ~:
  1845 
  1846 * new object-logic "Sequents" adds linear logic, while replacing LK
  1847 and Modal (thanks to Sara Kalvala);
  1848 
  1849 * HOL/Auth: correctness proofs for authentication protocols;
  1850 
  1851 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1852 examples on HOL/Auth);
  1853 
  1854 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1855 the rewriter and classical reasoner simultaneously;
  1856 
  1857 * function uresult no longer returns theorems in "standard" format;
  1858 regain previous version by: val uresult = standard o uresult;
  1859 
  1860 
  1861 
  1862 New in Isabelle94-6
  1863 -------------------
  1864 
  1865 * oracles -- these establish an interface between Isabelle and trusted
  1866 external reasoners, which may deliver results as theorems;
  1867 
  1868 * proof objects (in particular record all uses of oracles);
  1869 
  1870 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1871 
  1872 * "constdefs" section in theory files;
  1873 
  1874 * "primrec" section (HOL) no longer requires names;
  1875 
  1876 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1877 
  1878 
  1879 
  1880 New in Isabelle94-5
  1881 -------------------
  1882 
  1883 * reduced space requirements;
  1884 
  1885 * automatic HTML generation from theories;
  1886 
  1887 * theory files no longer require "..." (quotes) around most types;
  1888 
  1889 * new examples, including two proofs of the Church-Rosser theorem;
  1890 
  1891 * non-curried (1994) version of HOL is no longer distributed;
  1892 
  1893 
  1894 
  1895 New in Isabelle94-4
  1896 -------------------
  1897 
  1898 * greatly reduced space requirements;
  1899 
  1900 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1901 
  1902 * searchable theorem database (see the section "Retrieving theorems" on
  1903 page 8 of the Reference Manual);
  1904 
  1905 * new examples, including Grabczewski's monumental case study of the
  1906 Axiom of Choice;
  1907 
  1908 * The previous version of HOL renamed to Old_HOL;
  1909 
  1910 * The new version of HOL (previously called CHOL) uses a curried syntax
  1911 for functions.  Application looks like f a b instead of f(a,b);
  1912 
  1913 * Mutually recursive inductive definitions finally work in HOL;
  1914 
  1915 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1916 translates to the operator "split";
  1917 
  1918 
  1919 
  1920 New in Isabelle94-3
  1921 -------------------
  1922 
  1923 * new infix operator, addss, allowing the classical reasoner to
  1924 perform simplification at each step of its search.  Example:
  1925         fast_tac (cs addss ss)
  1926 
  1927 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1928 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1929 look like (a,b) instead of <a,b>;
  1930 
  1931 * PLEASE NOTE: CHOL will eventually replace HOL!
  1932 
  1933 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1934 It translates to the operator "split".  A new theory of integers is available;
  1935 
  1936 * In ZF, integer numerals now denote two's-complement binary integers.
  1937 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1938 
  1939 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1940 of the Axiom of Choice;
  1941 
  1942 
  1943 
  1944 New in Isabelle94-2
  1945 -------------------
  1946 
  1947 * Significantly faster resolution;
  1948 
  1949 * the different sections in a .thy file can now be mixed and repeated
  1950 freely;
  1951 
  1952 * Database of theorems for FOL, HOL and ZF.  New
  1953 commands including qed, qed_goal and bind_thm store theorems in the database.
  1954 
  1955 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1956 a given theory (thms_of), or find out what theory a theorem was proved in
  1957 (theory_of_thm);
  1958 
  1959 * Bugs fixed in the inductive definition and datatype packages;
  1960 
  1961 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1962 and HOL_dup_cs obsolete;
  1963 
  1964 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1965 have been removed;
  1966 
  1967 * Simpler definition of function space in ZF;
  1968 
  1969 * new results about cardinal and ordinal arithmetic in ZF;
  1970 
  1971 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1972 types;
  1973 
  1974 
  1975 $Id$