NEWS
author wenzelm
Tue Nov 06 23:50:24 2001 +0100 (2001-11-06)
changeset 12078 4eb8061286e5
parent 12034 4471077c4d4f
child 12106 4a8558dbb6a0
permissions -rw-r--r--
* Isar/Pure: proper integration with ``locales''; unlike the original
version by Florian Kammueller, Isar locales package high-level proof
contexts rather than raw logical ones (e.g. we admit to include
attributes everywhere);
* Isar/Pure: theory goals now support ad-hoc contexts, which are
discharged in the result, as in ``lemma (assumes A and B) K: A .'';
syntax coincides with that of a locale body;
     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   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    37   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    38   - moved induct/cases attributes to Pure, methods to Provers;
    39   - generic method setup instantiated for FOL and HOL;
    40 
    41   - 'case' command admits impromptu naming of parameters (such as
    42 "case (Suc n)");
    43 
    44   - 'induct' method divinates rule instantiation from the inductive
    45 claim; no longer requires excessive ?P bindings for proper
    46 instantiation of cases;
    47 
    48   - 'induct' method properly enumerates all possibilities of set/type
    49 rules; as a consequence facts may be also passed through *type* rules
    50 without further ado;
    51 
    52   - 'induct' method now derives symbolic cases from the *rulified*
    53 rule (before it used to rulify cases stemming from the internal
    54 atomized version); this means that the context of a non-atomic
    55 statement becomes is included in the hypothesis, avoiding the slightly
    56 cumbersome show "PROP ?case" form;
    57 
    58   - 'induct' may now use elim-style induction rules without chaining
    59 facts, using ``missing'' premises from the goal state; this allows
    60 rules stemming from inductive sets to be applied in unstructured
    61 scripts, while still benefitting from proper handling of non-atomic
    62 statements; NB: major inductive premises need to be put first, all the
    63 rest of the goal is passed through the induction;
    64 
    65 * Pure: proper integration with ``locales''; unlike the original
    66 version by Florian Kammueller, Isar locales package high-level proof
    67 contexts rather than raw logical ones (e.g. we admit to include
    68 attributes everywhere);
    69 
    70 * Pure: theory goals now support ad-hoc contexts, which are discharged
    71 in the result, as in ``lemma (assumes A and B) K: A .''; syntax
    72 coincides with that of a locale body;
    73 
    74 * Pure: renamed "antecedent" case to "rule_context";
    75 
    76 * Pure: added 'corollary' command;
    77 
    78 * Pure: fixed 'token_translation' command;
    79 
    80 * Pure: removed obsolete 'exported' attribute;
    81 
    82 * Pure: dummy pattern "_" in is/let is now automatically lifted over
    83 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
    84 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
    85 
    86 * Pure: method 'atomize' presents local goal premises as object-level
    87 statements (atomic meta-level propositions); setup controlled via
    88 rewrite rules declarations of 'atomize' attribute; example
    89 application: 'induct' method with proper rule statements in improper
    90 proof *scripts*;
    91 
    92 * Provers: 'simplified' attribute may refer to explicit rules instead
    93 of full simplifier context; 'iff' attribute handles conditional rules;
    94 
    95 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
    96 
    97 * HOL: 'recdef' now fails on unfinished automated proofs, use
    98 "(permissive)" option to recover old behavior;
    99 
   100 * HOL: 'inductive' no longer features separate (collective) attributes
   101 for 'intros' (was found too confusing);
   102 
   103 
   104 
   105 *** HOL ***
   106 
   107 * HOL: moved over to sane numeral syntax; the new policy is as
   108 follows:
   109 
   110   - 0 and 1 are polymorphic constants, which are defined on any
   111   numeric type (nat, int, real etc.);
   112 
   113   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   114   binary representation internally;
   115 
   116   - type nat has special constructor Suc, and generally prefers Suc 0
   117   over 1::nat and Suc (Suc 0) over 2::nat;
   118 
   119 This change may cause significant INCOMPATIBILITIES; here are some
   120 hints on converting existing sources:
   121 
   122   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   123   entities, so expressions involving "-" (unary or binary minus) need
   124   to be spaced properly;
   125 
   126   - existing occurrences of "1" may need to be constraint "1::nat" or
   127   even replaced by Suc 0; similar for old "2";
   128 
   129   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   130 
   131   - remove all special provisions on numerals in proofs;
   132 
   133 * HOL/record:
   134   - removed old "make" and "make_scheme" operations -- INCOMPATIBILITY;
   135   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   136   - provides cases/induct rules for use with corresponding Isar methods;
   137   - new derived operations "make" (for adding fields of current
   138     record), "extend" to promote fixed record to record scheme, and
   139     "truncate" for the reverse; cf. theorems "derived_defs", which are
   140     *not* declared as simp by default;
   141   - internal definitions directly based on a light-weight abstract
   142     theory of product types over typedef rather than datatype;
   143 
   144 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   145 
   146 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   147 (beware of argument permutation!);
   148 
   149 * HOL: linorder_less_split superseded by linorder_cases;
   150 
   151 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   152 to peripheral theory "Hilbert_Choice";
   153 
   154 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   155 in this (rare) case use:
   156 
   157   delSWrapper "split_all_tac"
   158   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   159 
   160 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   161 MAY FAIL;
   162 
   163 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   164 Isabelle's type classes, ^ on functions and relations has too general
   165 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   166 necessary to attach explicit type constraints;
   167 
   168 * HOL: syntax translations now work properly with numerals and records
   169 expressions;
   170 
   171 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   172 Florian Kammüller;
   173 
   174 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   175 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   176 renamed "Product_Type.unit";
   177 
   178 
   179 *** HOLCF ***
   180 
   181 * proper rep_datatype lift (see theory Lift); use plain induct_tac
   182 instead of former lift.induct_tac; always use UU instead of Undef;
   183 
   184 * 'domain' package adapted to new-style theories, e.g. see
   185 HOLCF/ex/Dnat.thy;
   186 
   187 
   188 *** ZF ***
   189 
   190 * ZF: the integer library now covers quotients and remainders, with
   191 many laws relating division to addition, multiplication, etc.;
   192 
   193 
   194 *** General ***
   195 
   196 * kernel: meta-level proof terms (by Stefan Berghofer), see also ref
   197 manual;
   198 
   199 * Pure/axclass: removed obsolete ML interface goal_subclass/goal_arity;
   200 
   201 * classical: renamed addaltern to addafter, addSaltern to addSafter;
   202 
   203 * clasimp: ``iff'' declarations now handle conditional rules as well;
   204 
   205 * syntax: new token syntax "num" for plain numerals (without "#" of
   206 "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now separate
   207 tokens, so expressions involving minus need to be spaced properly;
   208 
   209 * syntax: support non-oriented infixes;
   210 
   211 * syntax: print modes "type_brackets" and "no_type_brackets" control
   212 output of nested => (types); the default behavior is "type_brackets";
   213 
   214 * syntax: builtin parse translation for "_constify" turns valued
   215 tokens into AST constants;
   216 
   217 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   218 
   219 * system: Proof General keywords specification is now part of the
   220 Isabelle distribution (see etc/isar-keywords.el);
   221 
   222 * system: smart selection of Isabelle process versus Isabelle
   223 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   224 run both "isabelle" and "Isabelle" even if file names are badly
   225 damaged (executable inspects the case of the first letter of its own
   226 name); added separate "isabelle-process" and "isabelle-interface";
   227 
   228 
   229 
   230 New in Isabelle99-2 (February 2001)
   231 -----------------------------------
   232 
   233 *** Overview of INCOMPATIBILITIES ***
   234 
   235 * HOL: please note that theories in the Library and elsewhere often use the
   236 new-style (Isar) format; to refer to their theorems in an ML script you must
   237 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   238 
   239 * HOL: inductive package no longer splits induction rule aggressively,
   240 but only as far as specified by the introductions given; the old
   241 format may be recovered via ML function complete_split_rule or attribute
   242 'split_rule (complete)';
   243 
   244 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   245 gfp_Tarski to gfp_unfold;
   246 
   247 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   248 
   249 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   250 relation); infix "^^" has been renamed "``"; infix "``" has been
   251 renamed "`"; "univalent" has been renamed "single_valued";
   252 
   253 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   254 operation;
   255 
   256 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   257 
   258 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   259 
   260 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   261 consequence, it is no longer monotonic wrt. the local goal context
   262 (which is now passed through the inductive cases);
   263 
   264 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   265 \<gg> to \<ggreater>;
   266 
   267 
   268 *** Document preparation ***
   269 
   270 * \isabellestyle{NAME} selects version of Isabelle output (currently
   271 available: are "it" for near math-mode best-style output, "sl" for
   272 slanted text style, and "tt" for plain type-writer; if no
   273 \isabellestyle command is given, output is according to slanted
   274 type-writer);
   275 
   276 * support sub/super scripts (for single symbols only), input syntax is
   277 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   278 
   279 * some more standard symbols; see Appendix A of the system manual for
   280 the complete list of symbols defined in isabellesym.sty;
   281 
   282 * improved isabelle style files; more abstract symbol implementation
   283 (should now use \isamath{...} and \isatext{...} in custom symbol
   284 definitions);
   285 
   286 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   287 state; Note that presentation of goal states does not conform to
   288 actual human-readable proof documents.  Please do not include goal
   289 states into document output unless you really know what you are doing!
   290 
   291 * proper indentation of antiquoted output with proportional LaTeX
   292 fonts;
   293 
   294 * no_document ML operator temporarily disables LaTeX document
   295 generation;
   296 
   297 * isatool unsymbolize tunes sources for plain ASCII communication;
   298 
   299 
   300 *** Isar ***
   301 
   302 * Pure: Isar now suffers initial goal statements to contain unbound
   303 schematic variables (this does not conform to actual readable proof
   304 documents, due to unpredictable outcome and non-compositional proof
   305 checking); users who know what they are doing may use schematic goals
   306 for Prolog-style synthesis of proven results;
   307 
   308 * Pure: assumption method (an implicit finishing) now handles actual
   309 rules as well;
   310 
   311 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   312 initial goal, declare "that" only as Pure intro (only for single
   313 steps); the "that" rule assumption may now be involved in implicit
   314 finishing, thus ".." becomes a feasible for trivial obtains;
   315 
   316 * Pure: default proof step now includes 'intro_classes'; thus trivial
   317 instance proofs may be performed by "..";
   318 
   319 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   320 statements as well;
   321 
   322 * Pure: more robust selection of calculational rules;
   323 
   324 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   325 rule (as well as the assumption rule);
   326 
   327 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   328 lemmas, using the graph browser tool;
   329 
   330 * Pure: predict failure of "show" in interactive mode;
   331 
   332 * Pure: 'thms_containing' now takes actual terms as arguments;
   333 
   334 * HOL: improved method 'induct' --- now handles non-atomic goals
   335 (potential INCOMPATIBILITY); tuned error handling;
   336 
   337 * HOL: cases and induct rules now provide explicit hints about the
   338 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   339 any remaining facts are inserted into the goal verbatim;
   340 
   341 * HOL: local contexts (aka cases) may now contain term bindings as
   342 well; the 'cases' and 'induct' methods new provide a ?case binding for
   343 the result to be shown in each case;
   344 
   345 * HOL: added 'recdef_tc' command;
   346 
   347 * isatool convert assists in eliminating legacy ML scripts;
   348 
   349 
   350 *** HOL ***
   351 
   352 * HOL/Library: a collection of generic theories to be used together
   353 with main HOL; the theory loader path already includes this directory
   354 by default; the following existing theories have been moved here:
   355 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   356 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   357 
   358 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   359 modelling and verification task performed in Isabelle/HOL +
   360 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   361 
   362 * HOL/Algebra: special summation operator SUM no longer exists, it has
   363 been replaced by setsum; infix 'assoc' now has priority 50 (like
   364 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   365 'domain', this makes the theory consistent with mathematical
   366 literature;
   367 
   368 * HOL basics: added overloaded operations "inverse" and "divide"
   369 (infix "/"), syntax for generic "abs" operation, generic summation
   370 operator \<Sum>;
   371 
   372 * HOL/typedef: simplified package, provide more useful rules (see also
   373 HOL/subset.thy);
   374 
   375 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   376 now expressed as a proper nested rule (old-style tactic scripts may
   377 require atomize_strip_tac to cope with non-atomic premises);
   378 
   379 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   380 to "split_conv" (old name still available for compatibility);
   381 
   382 * HOL: improved concrete syntax for strings (e.g. allows translation
   383 rules with string literals);
   384 
   385 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   386 and Fleuriot's mechanization of analysis;
   387 
   388 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   389 
   390 
   391 *** CTT ***
   392 
   393 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   394 "lam" is displayed as TWO lambda-symbols
   395 
   396 * CTT: theory Main now available, containing everything (that is, Bool
   397 and Arith);
   398 
   399 
   400 *** General ***
   401 
   402 * Pure: the Simplifier has been implemented properly as a derived rule
   403 outside of the actual kernel (at last!); the overall performance
   404 penalty in practical applications is about 50%, while reliability of
   405 the Isabelle inference kernel has been greatly improved;
   406 
   407 * print modes "brackets" and "no_brackets" control output of nested =>
   408 (types) and ==> (props); the default behaviour is "brackets";
   409 
   410 * Provers: fast_tac (and friends) now handle actual object-logic rules
   411 as assumptions as well;
   412 
   413 * system: support Poly/ML 4.0;
   414 
   415 * system: isatool install handles KDE version 1 or 2;
   416 
   417 
   418 
   419 New in Isabelle99-1 (October 2000)
   420 ----------------------------------
   421 
   422 *** Overview of INCOMPATIBILITIES ***
   423 
   424 * HOL: simplification of natural numbers is much changed; to partly
   425 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   426 issue the following ML commands:
   427 
   428   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   429   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   430 
   431 * HOL: simplification no longer dives into case-expressions; this is
   432 controlled by "t.weak_case_cong" for each datatype t;
   433 
   434 * HOL: nat_less_induct renamed to less_induct;
   435 
   436 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   437 fixsome to patch .thy and .ML sources automatically;
   438 
   439   select_equality  -> some_equality
   440   select_eq_Ex     -> some_eq_ex
   441   selectI2EX       -> someI2_ex
   442   selectI2         -> someI2
   443   selectI          -> someI
   444   select1_equality -> some1_equality
   445   Eps_sym_eq       -> some_sym_eq_trivial
   446   Eps_eq           -> some_eq_trivial
   447 
   448 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   449 
   450 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   451 instead);
   452 
   453 * HOL: the recursion equations generated by 'recdef' are now called
   454 f.simps instead of f.rules;
   455 
   456 * HOL: qed_spec_mp now also handles bounded ALL as well;
   457 
   458 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   459 sometimes be needed;
   460 
   461 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   462 
   463 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   464 
   465 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   466 product is now "<*>" instead of "Times"; the lexicographic product is
   467 now "<*lex*>" instead of "**";
   468 
   469 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   470 of main HOL, but was unused); better use HOL's datatype package;
   471 
   472 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   473 the old syntax may be recovered as follows:
   474 
   475   syntax (symbols)
   476     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   477       (infixl "\\<oplus>" 100)
   478 
   479 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   480 
   481 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   482 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   483 internally;
   484 
   485 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   486 changed from A/r to A//r;
   487 
   488 * ZF: new treatment of arithmetic (nat & int) may break some old
   489 proofs;
   490 
   491 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   492 rulify -> rule_format, elimify -> elim_format, ...);
   493 
   494 * Isar/Provers: intro/elim/dest attributes changed; renamed
   495 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   496 should have to change intro!! to intro? only); replaced "delrule" by
   497 "rule del";
   498 
   499 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   500 
   501 * Provers: strengthened force_tac by using new first_best_tac;
   502 
   503 * LaTeX document preparation: several changes of isabelle.sty (see
   504 lib/texinputs);
   505 
   506 
   507 *** Document preparation ***
   508 
   509 * formal comments (text blocks etc.) in new-style theories may now
   510 contain antiquotations of thm/prop/term/typ/text to be presented
   511 according to latex print mode; concrete syntax is like this:
   512 @{term[show_types] "f(x) = a + x"};
   513 
   514 * isatool mkdir provides easy setup of Isabelle session directories,
   515 including proper document sources;
   516 
   517 * generated LaTeX sources are now deleted after successful run
   518 (isatool document -c); may retain a copy somewhere else via -D option
   519 of isatool usedir;
   520 
   521 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   522 style files, achieving self-contained LaTeX sources and simplifying
   523 LaTeX debugging;
   524 
   525 * old-style theories now produce (crude) LaTeX output as well;
   526 
   527 * browser info session directories are now self-contained (may be put
   528 on WWW server seperately); improved graphs of nested sessions; removed
   529 graph for 'all sessions';
   530 
   531 * several improvements in isabelle style files; \isabellestyle{it}
   532 produces fake math mode output; \isamarkupheader is now \section by
   533 default; see lib/texinputs/isabelle.sty etc.;
   534 
   535 
   536 *** Isar ***
   537 
   538 * Isar/Pure: local results and corresponding term bindings are now
   539 subject to Hindley-Milner polymorphism (similar to ML); this
   540 accommodates incremental type-inference very nicely;
   541 
   542 * Isar/Pure: new derived language element 'obtain' supports
   543 generalized existence reasoning;
   544 
   545 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   546 support accumulation of results, without applying any rules yet;
   547 useful to collect intermediate results without explicit name
   548 references, and for use with transitivity rules with more than 2
   549 premises;
   550 
   551 * Isar/Pure: scalable support for case-analysis type proofs: new
   552 'case' language element refers to local contexts symbolically, as
   553 produced by certain proof methods; internally, case names are attached
   554 to theorems as "tags";
   555 
   556 * Isar/Pure: theory command 'hide' removes declarations from
   557 class/type/const name spaces;
   558 
   559 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   560 indicate potential overloading;
   561 
   562 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   563 
   564 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   565 "{a,b,c}" instead of {a,b,c};
   566 
   567 * Isar/Pure now provides its own version of intro/elim/dest
   568 attributes; useful for building new logics, but beware of confusion
   569 with the version in Provers/classical;
   570 
   571 * Isar/Pure: the local context of (non-atomic) goals is provided via
   572 case name 'antecedent';
   573 
   574 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   575 to the current context is now done automatically);
   576 
   577 * Isar/Pure: theory command 'method_setup' provides a simple interface
   578 for definining proof methods in ML;
   579 
   580 * Isar/Provers: intro/elim/dest attributes changed; renamed
   581 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   582 most cases, one should have to change intro!! to intro? only);
   583 replaced "delrule" by "rule del";
   584 
   585 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   586 'symmetric' attribute (the latter supercedes [RS sym]);
   587 
   588 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   589 method modifier); 'simp' method: 'only:' modifier removes loopers as
   590 well (including splits);
   591 
   592 * Isar/Provers: Simplifier and Classical methods now support all kind
   593 of modifiers used in the past, including 'cong', 'iff', etc.
   594 
   595 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   596 of Simplifier and Classical reasoner);
   597 
   598 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   599 now support named cases; major packages (inductive, datatype, primrec,
   600 recdef) support case names and properly name parameters;
   601 
   602 * Isar/HOL: new transitivity rules for substitution in inequalities --
   603 monotonicity conditions are extracted to be proven at end of
   604 calculations;
   605 
   606 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   607 method anyway;
   608 
   609 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   610 split_if split_if_asm; datatype package provides theorems foo.splits =
   611 foo.split foo.split_asm for each datatype;
   612 
   613 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   614 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   615 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   616 use "(cases (simplified))" method in proper proof texts);
   617 
   618 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   619 
   620 * Isar: names of theorems etc. may be natural numbers as well;
   621 
   622 * Isar: 'pr' command: optional arguments for goals_limit and
   623 ProofContext.prems_limit; no longer prints theory contexts, but only
   624 proof states;
   625 
   626 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   627 additional print modes to be specified; e.g. "pr(latex)" will print
   628 proof state according to the Isabelle LaTeX style;
   629 
   630 * Isar: improved support for emulating tactic scripts, including proof
   631 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   632 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   633 (for HOL datatypes);
   634 
   635 * Isar: simplified (more robust) goal selection of proof methods: 1st
   636 goal, all goals, or explicit goal specifier (tactic emulation); thus
   637 'proof method scripts' have to be in depth-first order;
   638 
   639 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   640 
   641 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   642 should instead use individual commands for printing items
   643 (print_commands, print_methods etc.);
   644 
   645 * Isar: added 'nothing' --- the empty list of theorems;
   646 
   647 
   648 *** HOL ***
   649 
   650 * HOL/MicroJava: formalization of a fragment of Java, together with a
   651 corresponding virtual machine and a specification of its bytecode
   652 verifier and a lightweight bytecode verifier, including proofs of
   653 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   654 Cornelia Pusch (see also the homepage of project Bali at
   655 http://isabelle.in.tum.de/Bali/);
   656 
   657 * HOL/Algebra: new theory of rings and univariate polynomials, by
   658 Clemens Ballarin;
   659 
   660 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   661 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   662 Rasmussen;
   663 
   664 * HOL/Lattice: fundamental concepts of lattice theory and order
   665 structures, including duals, properties of bounds versus algebraic
   666 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   667 Theorem for complete lattices etc.; may also serve as a demonstration
   668 for abstract algebraic reasoning using axiomatic type classes, and
   669 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   670 
   671 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   672 von Oheimb;
   673 
   674 * HOL/IMPP: extension of IMP with local variables and mutually
   675 recursive procedures, by David von Oheimb;
   676 
   677 * HOL/Lambda: converted into new-style theory and document;
   678 
   679 * HOL/ex/Multiquote: example of multiple nested quotations and
   680 anti-quotations -- basically a generalized version of de-Bruijn
   681 representation; very useful in avoiding lifting of operations;
   682 
   683 * HOL/record: added general record equality rule to simpset; fixed
   684 select-update simplification procedure to handle extended records as
   685 well; admit "r" as field name;
   686 
   687 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   688 other numeric types and also as the identity of groups, rings, etc.;
   689 
   690 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   691 Types nat and int belong to this axclass;
   692 
   693 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   694    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   695    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   696   two terms #m*u and #n*u are replaced by #(m+n)*u
   697     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   698   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   699     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   700 
   701 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   702 powerful prover for predicate logic but knows nothing of clasets; see
   703 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   704 
   705 * HOL: new version of "case_tac" subsumes both boolean case split and
   706 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   707 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   708 
   709 * HOL: simplification no longer dives into case-expressions: only the
   710 selector expression is simplified, but not the remaining arms; to
   711 enable full simplification of case-expressions for datatype t, you may
   712 remove t.weak_case_cong from the simpset, either globally (Delcongs
   713 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   714 
   715 * HOL/recdef: the recursion equations generated by 'recdef' for
   716 function 'f' are now called f.simps instead of f.rules; if all
   717 termination conditions are proved automatically, these simplification
   718 rules are added to the simpset, as in primrec; rules may be named
   719 individually as well, resulting in a separate list of theorems for
   720 each equation;
   721 
   722 * HOL/While is a new theory that provides a while-combinator. It
   723 permits the definition of tail-recursive functions without the
   724 provision of a termination measure. The latter is necessary once the
   725 invariant proof rule for while is applied.
   726 
   727 * HOL: new (overloaded) notation for the set of elements below/above
   728 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   729 
   730 * HOL: theorems impI, allI, ballI bound as "strip";
   731 
   732 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   733 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   734 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   735 
   736 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   737 
   738 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   739 main HOL, but was unused);
   740 
   741 * HOL: fewer consts declared as global (e.g. have to refer to
   742 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   743 
   744 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   745 in case of overlap with user translations (e.g. judgements over
   746 tuples); (note that the underlying logical represenation is still
   747 bogus);
   748 
   749 
   750 *** ZF ***
   751 
   752 * ZF: simplification automatically cancels common terms in arithmetic
   753 expressions over nat and int;
   754 
   755 * ZF: new treatment of nat to minimize type-checking: all operators
   756 coerce their operands to a natural number using the function natify,
   757 making the algebraic laws unconditional;
   758 
   759 * ZF: as above, for int: operators coerce their operands to an integer
   760 using the function intify;
   761 
   762 * ZF: the integer library now contains many of the usual laws for the
   763 orderings, including $<=, and monotonicity laws for $+ and $*;
   764 
   765 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   766 simplification;
   767 
   768 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   769 to the simplifier and classical reasoner simultaneously;
   770 
   771 
   772 *** General ***
   773 
   774 * Provers: blast_tac now handles actual object-logic rules as
   775 assumptions; note that auto_tac uses blast_tac internally as well;
   776 
   777 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   778 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   779 
   780 * Provers: delrules now handles destruct rules as well (no longer need
   781 explicit make_elim);
   782 
   783 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   784   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   785 use instead the strong form,
   786   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   787 in HOL, FOL and ZF the function cla_make_elim will create such rules
   788 from destruct-rules;
   789 
   790 * Provers: Simplifier.easy_setup provides a fast path to basic
   791 Simplifier setup for new object-logics;
   792 
   793 * Pure: AST translation rules no longer require constant head on LHS;
   794 
   795 * Pure: improved name spaces: ambiguous output is qualified; support
   796 for hiding of names;
   797 
   798 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   799 XSYMBOL_HOME; no longer need to do manual configuration in most
   800 situations;
   801 
   802 * system: compression of ML heaps images may now be controlled via -c
   803 option of isabelle and isatool usedir (currently only observed by
   804 Poly/ML);
   805 
   806 * system: isatool installfonts may handle X-Symbol fonts as well (very
   807 useful for remote X11);
   808 
   809 * system: provide TAGS file for Isabelle sources;
   810 
   811 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   812 order;
   813 
   814 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   815 timing flag supersedes proof_timing and Toplevel.trace;
   816 
   817 * ML: new combinators |>> and |>>> for incremental transformations
   818 with secondary results (e.g. certain theory extensions):
   819 
   820 * ML: PureThy.add_defs gets additional argument to indicate potential
   821 overloading (usually false);
   822 
   823 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   824 results;
   825 
   826 
   827 
   828 New in Isabelle99 (October 1999)
   829 --------------------------------
   830 
   831 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   832 
   833 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   834 are no longer simplified.  (This allows the simplifier to unfold recursive
   835 functional programs.)  To restore the old behaviour, declare
   836 
   837     Delcongs [if_weak_cong];
   838 
   839 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   840 complement;
   841 
   842 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   843 
   844 * HOL/datatype: mutual_induct_tac no longer exists --
   845   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   846 
   847 * HOL/typedef: fixed type inference for representing set; type
   848 arguments now have to occur explicitly on the rhs as type constraints;
   849 
   850 * ZF: The con_defs part of an inductive definition may no longer refer
   851 to constants declared in the same theory;
   852 
   853 * HOL, ZF: the function mk_cases, generated by the inductive
   854 definition package, has lost an argument.  To simplify its result, it
   855 uses the default simpset instead of a supplied list of theorems.
   856 
   857 * HOL/List: the constructors of type list are now Nil and Cons;
   858 
   859 * Simplifier: the type of the infix ML functions
   860         setSSolver addSSolver setSolver addSolver
   861 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   862 for packaging solvers. A solver is created via
   863         mk_solver: string -> (thm list -> int -> tactic) -> solver
   864 where the string argument is only a comment.
   865 
   866 
   867 *** Proof tools ***
   868 
   869 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   870 decision procedure for linear arithmetic. Currently it is used for
   871 types `nat', `int', and `real' in HOL (see below); it can, should and
   872 will be instantiated for other types and logics as well.
   873 
   874 * The simplifier now accepts rewrite rules with flexible heads, eg
   875      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   876   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   877   matching.
   878 
   879 
   880 *** General ***
   881 
   882 * New Isabelle/Isar subsystem provides an alternative to traditional
   883 tactical theorem proving; together with the ProofGeneral/isar user
   884 interface it offers an interactive environment for developing human
   885 readable proof documents (Isar == Intelligible semi-automated
   886 reasoning); for further information see isatool doc isar-ref,
   887 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   888 
   889 * improved and simplified presentation of theories: better HTML markup
   890 (including colors), graph views in several sizes; isatool usedir now
   891 provides a proper interface for user theories (via -P option); actual
   892 document preparation based on (PDF)LaTeX is available as well (for
   893 new-style theories only); see isatool doc system for more information;
   894 
   895 * native support for Proof General, both for classic Isabelle and
   896 Isabelle/Isar;
   897 
   898 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   899 using the graph browser tool;
   900 
   901 * Isabelle manuals now also available as PDF;
   902 
   903 * theory loader rewritten from scratch (may not be fully
   904 bug-compatible); old loadpath variable has been replaced by show_path,
   905 add_path, del_path, reset_path functions; new operations such as
   906 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   907 isatool doc ref);
   908 
   909 * improved isatool install: option -k creates KDE application icon,
   910 option -p DIR installs standalone binaries;
   911 
   912 * added ML_PLATFORM setting (useful for cross-platform installations);
   913 more robust handling of platform specific ML images for SML/NJ;
   914 
   915 * the settings environment is now statically scoped, i.e. it is never
   916 created again in sub-processes invoked from isabelle, isatool, or
   917 Isabelle;
   918 
   919 * path element specification '~~' refers to '$ISABELLE_HOME';
   920 
   921 * in locales, the "assumes" and "defines" parts may be omitted if
   922 empty;
   923 
   924 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   925 long arrows);
   926 
   927 * new print_mode "HTML";
   928 
   929 * new flag show_tags controls display of tags of theorems (which are
   930 basically just comments that may be attached by some tools);
   931 
   932 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   933 mode and goal output format:
   934 
   935 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   936 244c244
   937 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   938 ---
   939 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   940 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   941 181c181
   942 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   943 ---
   944 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   945 
   946 * function bind_thms stores lists of theorems (cf. bind_thm);
   947 
   948 * new shorthand tactics ftac, eatac, datac, fatac;
   949 
   950 * qed (and friends) now accept "" as result name; in that case the
   951 theorem is not stored, but proper checks and presentation of the
   952 result still apply;
   953 
   954 * theorem database now also indexes constants "Trueprop", "all",
   955 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   956 
   957 
   958 *** HOL ***
   959 
   960 ** HOL arithmetic **
   961 
   962 * There are now decision procedures for linear arithmetic over nat and
   963 int:
   964 
   965 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   966 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   967 are treated as atomic; subformulae not involving type `nat' or `int'
   968 are ignored; quantified subformulae are ignored unless they are
   969 positive universal or negative existential. The tactic has to be
   970 invoked by hand and can be a little bit slow. In particular, the
   971 running time is exponential in the number of occurrences of `min' and
   972 `max', and `-' on `nat'.
   973 
   974 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   975 (negated) (in)equalities among the premises and the conclusion into
   976 account (i.e. no compound formulae) and does not know about `min' and
   977 `max', and `-' on `nat'. It is fast and is used automatically by the
   978 simplifier.
   979 
   980 NB: At the moment, these decision procedures do not cope with mixed
   981 nat/int formulae where the two parts interact, such as `m < n ==>
   982 int(m) < int(n)'.
   983 
   984 * HOL/Numeral provides a generic theory of numerals (encoded
   985 efficiently as bit strings); setup for types nat/int/real is in place;
   986 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   987 int, existing theories and proof scripts may require a few additional
   988 type constraints;
   989 
   990 * integer division and remainder can now be performed on constant
   991 arguments;
   992 
   993 * many properties of integer multiplication, division and remainder
   994 are now available;
   995 
   996 * An interface to the Stanford Validity Checker (SVC) is available through the
   997 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   998 are proved automatically.  SVC must be installed separately, and its results
   999 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1000 invocation of the underlying oracle).  For SVC see
  1001   http://verify.stanford.edu/SVC
  1002 
  1003 * IsaMakefile: the HOL-Real target now builds an actual image;
  1004 
  1005 
  1006 ** HOL misc **
  1007 
  1008 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1009 (in Isabelle/Isar) -- by Gertrud Bauer;
  1010 
  1011 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1012 analysis for assembly languages with subtypes;
  1013 
  1014 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1015 -- avoids syntactic ambiguities and treats state, transition, and
  1016 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1017 changed syntax and (many) tactics;
  1018 
  1019 * HOL/inductive: Now also handles more general introduction rules such
  1020   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1021   theorems are now maintained within the theory (maintained via the
  1022   "mono" attribute);
  1023 
  1024 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1025   (using function types) such as
  1026 
  1027   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1028 
  1029 * HOL/record: record_simproc (part of the default simpset) takes care
  1030 of selectors applied to updated records; record_split_tac is no longer
  1031 part of the default claset; update_defs may now be removed from the
  1032 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1033 
  1034   claset_ref () := claset() addSWrapper record_split_wrapper;
  1035   Delsimprocs [record_simproc]
  1036 
  1037 * HOL/typedef: fixed type inference for representing set; type
  1038 arguments now have to occur explicitly on the rhs as type constraints;
  1039 
  1040 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1041 names rather than an ML expression;
  1042 
  1043 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1044 supplied later.  Program schemes can be defined, such as
  1045     "While B C s = (if B s then While B C (C s) else s)"
  1046 where the well-founded relation can be chosen after B and C have been given.
  1047 
  1048 * HOL/List: the constructors of type list are now Nil and Cons;
  1049 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1050 course, ML tools referring to List.list.op # etc. have to be adapted;
  1051 
  1052 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1053 disabled by default; run isabelle with option -m HOL to get back to
  1054 the original Gordon/HOL-style output;
  1055 
  1056 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1057 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1058 
  1059 * HOL basic syntax simplified (more orthogonal): all variants of
  1060 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1061 Eps operator is provided as well: "SOME x. P[x]";
  1062 
  1063 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1064 
  1065 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1066 thus available for user theories;
  1067 
  1068 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1069 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1070 time;
  1071 
  1072 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1073 several times and then mp;
  1074 
  1075 
  1076 *** LK ***
  1077 
  1078 * the notation <<...>> is now available as a notation for sequences of
  1079 formulas;
  1080 
  1081 * the simplifier is now installed
  1082 
  1083 * the axiom system has been generalized (thanks to Soren Heilmann)
  1084 
  1085 * the classical reasoner now has a default rule database
  1086 
  1087 
  1088 *** ZF ***
  1089 
  1090 * new primrec section allows primitive recursive functions to be given
  1091 directly (as in HOL) over datatypes and the natural numbers;
  1092 
  1093 * new tactics induct_tac and exhaust_tac for induction (or case
  1094 analysis) over datatypes and the natural numbers;
  1095 
  1096 * the datatype declaration of type T now defines the recursor T_rec;
  1097 
  1098 * simplification automatically does freeness reasoning for datatype
  1099 constructors;
  1100 
  1101 * automatic type-inference, with AddTCs command to insert new
  1102 type-checking rules;
  1103 
  1104 * datatype introduction rules are now added as Safe Introduction rules
  1105 to the claset;
  1106 
  1107 * the syntax "if P then x else y" is now available in addition to
  1108 if(P,x,y);
  1109 
  1110 
  1111 *** Internal programming interfaces ***
  1112 
  1113 * tuned simplifier trace output; new flag debug_simp;
  1114 
  1115 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1116 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1117 
  1118 * AxClass.axclass_tac lost the theory argument;
  1119 
  1120 * tuned current_goals_markers semantics: begin / end goal avoids
  1121 printing empty lines;
  1122 
  1123 * removed prs and prs_fn hook, which was broken because it did not
  1124 include \n in its semantics, forcing writeln to add one
  1125 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1126 string -> unit if you really want to output text without newline;
  1127 
  1128 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1129 plain output, interface builders may have to enable 'isabelle_font'
  1130 mode to get Isabelle font glyphs as before;
  1131 
  1132 * refined token_translation interface; INCOMPATIBILITY: output length
  1133 now of type real instead of int;
  1134 
  1135 * theory loader actions may be traced via new ThyInfo.add_hook
  1136 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1137 your own database of information attached to *whole* theories -- as
  1138 opposed to intra-theory data slots offered via TheoryDataFun;
  1139 
  1140 * proper handling of dangling sort hypotheses (at last!);
  1141 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1142 extra sort hypotheses that can be witnessed from the type signature;
  1143 the force_strip_shyps flag is gone, any remaining shyps are simply
  1144 left in the theorem (with a warning issued by strip_shyps_warning);
  1145 
  1146 
  1147 
  1148 New in Isabelle98-1 (October 1998)
  1149 ----------------------------------
  1150 
  1151 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1152 
  1153 * several changes of automated proof tools;
  1154 
  1155 * HOL: major changes to the inductive and datatype packages, including
  1156 some minor incompatibilities of theory syntax;
  1157 
  1158 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1159 called `inj_on';
  1160 
  1161 * HOL: removed duplicate thms in Arith:
  1162   less_imp_add_less  should be replaced by  trans_less_add1
  1163   le_imp_add_le      should be replaced by  trans_le_add1
  1164 
  1165 * HOL: unary minus is now overloaded (new type constraints may be
  1166 required);
  1167 
  1168 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1169 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1170 now taken as an integer constant.
  1171 
  1172 * Pure: ML function 'theory_of' renamed to 'theory';
  1173 
  1174 
  1175 *** Proof tools ***
  1176 
  1177 * Simplifier:
  1178   1. Asm_full_simp_tac is now more aggressive.
  1179      1. It will sometimes reorient premises if that increases their power to
  1180         simplify.
  1181      2. It does no longer proceed strictly from left to right but may also
  1182         rotate premises to achieve further simplification.
  1183      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1184      old Asm_full_simp_tac in that it does not rotate premises.
  1185   2. The simplifier now knows a little bit about nat-arithmetic.
  1186 
  1187 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1188 allows for selected deletion of wrappers, by introduction of names for
  1189 wrapper functionals.  This implies that addbefore, addSbefore,
  1190 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1191 and that adding two tactics with the same name overwrites the first
  1192 one (emitting a warning).
  1193   type wrapper = (int -> tactic) -> (int -> tactic)
  1194   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1195   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1196   delWrapper, delSWrapper: claset *  string            -> claset
  1197   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1198 
  1199 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1200 semantics; addbefore now affects only the unsafe part of step_tac
  1201 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1202 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1203 by Force_tac;
  1204 
  1205 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1206 compWrapper; added safe wrapper (and access functions for it);
  1207 
  1208 * HOL/split_all_tac is now much faster and fails if there is nothing
  1209 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1210 and the names of the automatically generated variables have changed.
  1211 split_all_tac has moved within claset() from unsafe wrappers to safe
  1212 wrappers, which means that !!-bound variables are split much more
  1213 aggressively, and safe_tac and clarify_tac now split such variables.
  1214 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1215 Note: the same holds for record_split_tac, which does the job of
  1216 split_all_tac for record fields.
  1217 
  1218 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1219 permanently to the default simpset using Addsplits just like
  1220 Addsimps. They can be removed via Delsplits just like
  1221 Delsimps. Lower-case versions are also available.
  1222 
  1223 * HOL/Simplifier: The rule split_if is now part of the default
  1224 simpset. This means that the simplifier will eliminate all occurrences
  1225 of if-then-else in the conclusion of a goal. To prevent this, you can
  1226 either remove split_if completely from the default simpset by
  1227 `Delsplits [split_if]' or remove it in a specific call of the
  1228 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1229 other case splitting rules to/from the default simpset: every datatype
  1230 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1231 t is the name of the datatype).
  1232 
  1233 * Classical reasoner / Simplifier combination: new force_tac (and
  1234 derivatives Force_tac, force) combines rewriting and classical
  1235 reasoning (and whatever other tools) similarly to auto_tac, but is
  1236 aimed to solve the given subgoal completely.
  1237 
  1238 
  1239 *** General ***
  1240 
  1241 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1242 and `goalw': the theory is no longer needed as an explicit argument -
  1243 the current theory context is used; assumptions are no longer returned
  1244 at the ML-level unless one of them starts with ==> or !!; it is
  1245 recommended to convert to these new commands using isatool fixgoal
  1246 (backup your sources first!);
  1247 
  1248 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1249 the current theory context, and 'theory' to lookup stored theories;
  1250 
  1251 * new theory section 'locale' for declaring constants, assumptions and
  1252 definitions that have local scope;
  1253 
  1254 * new theory section 'nonterminals' for purely syntactic types;
  1255 
  1256 * new theory section 'setup' for generic ML setup functions
  1257 (e.g. package initialization);
  1258 
  1259 * the distribution now includes Isabelle icons: see
  1260 lib/logo/isabelle-{small,tiny}.xpm;
  1261 
  1262 * isatool install - install binaries with absolute references to
  1263 ISABELLE_HOME/bin;
  1264 
  1265 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1266 
  1267 * print mode 'emacs' reserved for Isamode;
  1268 
  1269 * support multiple print (ast) translations per constant name;
  1270 
  1271 * theorems involving oracles are now printed with a suffixed [!];
  1272 
  1273 
  1274 *** HOL ***
  1275 
  1276 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1277 
  1278 * HOL/inductive package reorganized and improved: now supports mutual
  1279 definitions such as
  1280 
  1281   inductive EVEN ODD
  1282     intrs
  1283       null "0 : EVEN"
  1284       oddI "n : EVEN ==> Suc n : ODD"
  1285       evenI "n : ODD ==> Suc n : EVEN"
  1286 
  1287 new theorem list "elims" contains an elimination rule for each of the
  1288 recursive sets; inductive definitions now handle disjunctive premises
  1289 correctly (also ZF);
  1290 
  1291 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1292 "mutual_induct" no longer exists - the induction rule is always
  1293 contained in "induct";
  1294 
  1295 
  1296 * HOL/datatype package re-implemented and greatly improved: now
  1297 supports mutually recursive datatypes such as
  1298 
  1299   datatype
  1300     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1301             | SUM ('a aexp) ('a aexp)
  1302             | DIFF ('a aexp) ('a aexp)
  1303             | NUM 'a
  1304   and
  1305     'a bexp = LESS ('a aexp) ('a aexp)
  1306             | AND ('a bexp) ('a bexp)
  1307             | OR ('a bexp) ('a bexp)
  1308 
  1309 as well as indirectly recursive datatypes such as
  1310 
  1311   datatype
  1312     ('a, 'b) term = Var 'a
  1313                   | App 'b ((('a, 'b) term) list)
  1314 
  1315 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1316 induction on mutually / indirectly recursive datatypes.
  1317 
  1318 Primrec equations are now stored in theory and can be accessed via
  1319 <function_name>.simps.
  1320 
  1321 INCOMPATIBILITIES:
  1322 
  1323   - Theories using datatypes must now have theory Datatype as an
  1324     ancestor.
  1325   - The specific <typename>.induct_tac no longer exists - use the
  1326     generic induct_tac instead.
  1327   - natE has been renamed to nat.exhaust - use exhaust_tac
  1328     instead of res_inst_tac ... natE. Note that the variable
  1329     names in nat.exhaust differ from the names in natE, this
  1330     may cause some "fragile" proofs to fail.
  1331   - The theorems split_<typename>_case and split_<typename>_case_asm
  1332     have been renamed to <typename>.split and <typename>.split_asm.
  1333   - Since default sorts of type variables are now handled correctly,
  1334     some datatype definitions may have to be annotated with explicit
  1335     sort constraints.
  1336   - Primrec definitions no longer require function name and type
  1337     of recursive argument.
  1338 
  1339 Consider using isatool fixdatatype to adapt your theories and proof
  1340 scripts to the new package (backup your sources first!).
  1341 
  1342 
  1343 * HOL/record package: considerably improved implementation; now
  1344 includes concrete syntax for record types, terms, updates; theorems
  1345 for surjective pairing and splitting !!-bound record variables; proof
  1346 support is as follows:
  1347 
  1348   1) standard conversions (selectors or updates applied to record
  1349 constructor terms) are part of the standard simpset;
  1350 
  1351   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1352 made part of standard simpset and claset via addIffs;
  1353 
  1354   3) a tactic for record field splitting (record_split_tac) is part of
  1355 the standard claset (addSWrapper);
  1356 
  1357 To get a better idea about these rules you may retrieve them via
  1358 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1359 the name of your record type.
  1360 
  1361 The split tactic 3) conceptually simplifies by the following rule:
  1362 
  1363   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1364 
  1365 Thus any record variable that is bound by meta-all will automatically
  1366 blow up into some record constructor term, consequently the
  1367 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1368 solve record problems automatically.
  1369 
  1370 
  1371 * reorganized the main HOL image: HOL/Integ and String loaded by
  1372 default; theory Main includes everything;
  1373 
  1374 * automatic simplification of integer sums and comparisons, using cancellation;
  1375 
  1376 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1377 
  1378 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1379 
  1380 * many new identities for unions, intersections, set difference, etc.;
  1381 
  1382 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1383 called split_if, split_split, split_sum_case and split_nat_case (to go
  1384 with add/delsplits);
  1385 
  1386 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1387 (?x::unit) = (); this is made part of the default simpset, which COULD
  1388 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1389 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1390 unit_abs_eta_conv is added in order to counter the effect of
  1391 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1392 %u.f();
  1393 
  1394 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1395 makes more sense);
  1396 
  1397 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1398   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1399   disjointness reasoning but breaking a few old proofs.
  1400 
  1401 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1402 to 'converse' from 'inverse' (for compatibility with ZF and some
  1403 literature);
  1404 
  1405 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1406 the well-founded relation;
  1407 
  1408 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1409     Compl A.  The "Compl" syntax remains available as input syntax for this
  1410     release ONLY.
  1411 
  1412 * HOL/Update: new theory of function updates:
  1413     f(a:=b) == %x. if x=a then b else f x
  1414 may also be iterated as in f(a:=b,c:=d,...);
  1415 
  1416 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1417 
  1418 * HOL/List:
  1419   - new function list_update written xs[i:=v] that updates the i-th
  1420     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1421   - new function `upt' written [i..j(] which generates the list
  1422     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1423     bound write [i..j], which is a shorthand for [i..j+1(].
  1424   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1425 
  1426 * HOL/Arith:
  1427   - removed 'pred' (predecessor) function;
  1428   - generalized some theorems about n-1;
  1429   - many new laws about "div" and "mod";
  1430   - new laws about greatest common divisors (see theory ex/Primes);
  1431 
  1432 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1433 instead of "inverse";
  1434 
  1435 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1436   of the multiset ordering;
  1437 
  1438 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1439   (not included by default);
  1440 
  1441 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1442 
  1443 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1444   programs, i.e. different program variables may have different types.
  1445 
  1446 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1447   [previously, this check worked only if the rewrite rule was unconditional]
  1448   Now rew can involve either definitions or equalities (either == or =).
  1449 
  1450 
  1451 *** ZF ***
  1452 
  1453 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1454   only the theorems proved on ZF.ML;
  1455 
  1456 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1457   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1458   disjointness reasoning but breaking a few old proofs.
  1459 
  1460 * ZF/Update: new theory of function updates
  1461     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1462   may also be iterated as in f(a:=b,c:=d,...);
  1463 
  1464 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1465 
  1466 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1467   [previously, this check worked only if the rewrite rule was unconditional]
  1468   Now rew can involve either definitions or equalities (either == or =).
  1469 
  1470 * case_tac provided for compatibility with HOL
  1471     (like the old excluded_middle_tac, but with subgoals swapped)
  1472 
  1473 
  1474 *** Internal programming interfaces ***
  1475 
  1476 * Pure: several new basic modules made available for general use, see
  1477 also src/Pure/README;
  1478 
  1479 * improved the theory data mechanism to support encapsulation (data
  1480 kind name replaced by private Object.kind, acting as authorization
  1481 key); new type-safe user interface via functor TheoryDataFun; generic
  1482 print_data function becomes basically useless;
  1483 
  1484 * removed global_names compatibility flag -- all theory declarations
  1485 are qualified by default;
  1486 
  1487 * module Pure/Syntax now offers quote / antiquote translation
  1488 functions (useful for Hoare logic etc. with implicit dependencies);
  1489 see HOL/ex/Antiquote for an example use;
  1490 
  1491 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1492 cterm -> thm;
  1493 
  1494 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1495 subgoal;
  1496 
  1497 * Display.print_goals function moved to Locale.print_goals;
  1498 
  1499 * standard print function for goals supports current_goals_markers
  1500 variable for marking begin of proof, end of proof, start of goal; the
  1501 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1502 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1503 for example;
  1504 
  1505 
  1506 
  1507 New in Isabelle98 (January 1998)
  1508 --------------------------------
  1509 
  1510 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1511 
  1512 * changed lexical syntax of terms / types: dots made part of long
  1513 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1514 
  1515 * simpset (and claset) reference variable replaced by functions
  1516 simpset / simpset_ref;
  1517 
  1518 * no longer supports theory aliases (via merge) and non-trivial
  1519 implicit merge of thms' signatures;
  1520 
  1521 * most internal names of constants changed due to qualified names;
  1522 
  1523 * changed Pure/Sequence interface (see Pure/seq.ML);
  1524 
  1525 
  1526 *** General Changes ***
  1527 
  1528 * hierachically structured name spaces (for consts, types, axms, thms
  1529 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1530 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1531 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1532 long_names for fully qualified output names; NOTE: ML programs
  1533 (special tactics, packages etc.) referring to internal names may have
  1534 to be adapted to cope with fully qualified names; in case of severe
  1535 backward campatibility problems try setting 'global_names' at compile
  1536 time to have enrything declared within a flat name space; one may also
  1537 fine tune name declarations in theories via the 'global' and 'local'
  1538 section;
  1539 
  1540 * reimplemented the implicit simpset and claset using the new anytype
  1541 data filed in signatures; references simpset:simpset ref etc. are
  1542 replaced by functions simpset:unit->simpset and
  1543 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1544 to patch your ML files accordingly;
  1545 
  1546 * HTML output now includes theory graph data for display with Java
  1547 applet or isatool browser; data generated automatically via isatool
  1548 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1549 
  1550 * defs may now be conditional; improved rewrite_goals_tac to handle
  1551 conditional equations;
  1552 
  1553 * defs now admits additional type arguments, using TYPE('a) syntax;
  1554 
  1555 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1556 creates a new theory node; implicit merge of thms' signatures is
  1557 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1558 transfer:theory->thm->thm in (rare) cases;
  1559 
  1560 * improved handling of draft signatures / theories; draft thms (and
  1561 ctyps, cterms) are automatically promoted to real ones;
  1562 
  1563 * slightly changed interfaces for oracles: admit many per theory, named
  1564 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1565 
  1566 * print_goals: optional output of const types (set show_consts and
  1567 show_types);
  1568 
  1569 * improved output of warnings (###) and errors (***);
  1570 
  1571 * subgoal_tac displays a warning if the new subgoal has type variables;
  1572 
  1573 * removed old README and Makefiles;
  1574 
  1575 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1576 
  1577 * removed obsolete init_pps and init_database;
  1578 
  1579 * deleted the obsolete tactical STATE, which was declared by
  1580     fun STATE tacfun st = tacfun st st;
  1581 
  1582 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1583 (which abbreviates $HOME);
  1584 
  1585 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1586 use isatool fixseq to adapt your ML programs (this works for fully
  1587 qualified references to the Sequence structure only!);
  1588 
  1589 * use_thy no longer requires writable current directory; it always
  1590 reloads .ML *and* .thy file, if either one is out of date;
  1591 
  1592 
  1593 *** Classical Reasoner ***
  1594 
  1595 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1596 tactics that use classical reasoning to simplify a subgoal without
  1597 splitting it into several subgoals;
  1598 
  1599 * Safe_tac: like safe_tac but uses the default claset;
  1600 
  1601 
  1602 *** Simplifier ***
  1603 
  1604 * added simplification meta rules:
  1605     (asm_)(full_)simplify: simpset -> thm -> thm;
  1606 
  1607 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1608 logics (again);
  1609 
  1610 * added prems argument to simplification procedures;
  1611 
  1612 * HOL, FOL, ZF: added infix function `addsplits':
  1613   instead of `<simpset> setloop (split_tac <thms>)'
  1614   you can simply write `<simpset> addsplits <thms>'
  1615 
  1616 
  1617 *** Syntax ***
  1618 
  1619 * TYPE('a) syntax for type reflection terms;
  1620 
  1621 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1622 
  1623 * pretty printer: changed order of mixfix annotation preference (again!);
  1624 
  1625 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1626 
  1627 
  1628 *** HOL ***
  1629 
  1630 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1631   with `addloop' of the simplifier to faciliate case splitting in premises.
  1632 
  1633 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1634 
  1635 * HOL/Auth: new protocol proofs including some for the Internet
  1636   protocol TLS;
  1637 
  1638 * HOL/Map: new theory of `maps' a la VDM;
  1639 
  1640 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1641 cancelling out common nat summands from =, <, <= (in)equalities, or
  1642 differences; simplification procedures nat_cancel_factor for
  1643 cancelling common factor from =, <, <= (in)equalities over natural
  1644 sums; nat_cancel contains both kinds of procedures, it is installed by
  1645 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1646 
  1647 * HOL/simplifier: terms of the form
  1648   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1649   are rewritten to
  1650   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1651   and those of the form
  1652   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1653   are rewritten to
  1654   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1655 
  1656 * HOL/datatype
  1657   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1658 
  1659   P(t_case f1 ... fn x) =
  1660      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1661         ...
  1662        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1663      )
  1664 
  1665   and a theorem `split_t_case_asm' of the form
  1666 
  1667   P(t_case f1 ... fn x) =
  1668     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1669         ...
  1670        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1671      )
  1672   which can be added to a simpset via `addsplits'. The existing theorems
  1673   expand_list_case and expand_option_case have been renamed to
  1674   split_list_case and split_option_case.
  1675 
  1676 * HOL/Arithmetic:
  1677   - `pred n' is automatically converted to `n-1'.
  1678     Users are strongly encouraged not to use `pred' any longer,
  1679     because it will disappear altogether at some point.
  1680   - Users are strongly encouraged to write "0 < n" rather than
  1681     "n ~= 0". Theorems and proof tools have been modified towards this
  1682     `standard'.
  1683 
  1684 * HOL/Lists:
  1685   the function "set_of_list" has been renamed "set" (and its theorems too);
  1686   the function "nth" now takes its arguments in the reverse order and
  1687   has acquired the infix notation "!" as in "xs!n".
  1688 
  1689 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1690 
  1691 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1692   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1693 
  1694 * HOL/record: extensible records with schematic structural subtyping
  1695 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1696 still lacks various theorems and concrete record syntax;
  1697 
  1698 
  1699 *** HOLCF ***
  1700 
  1701 * removed "axioms" and "generated by" sections;
  1702 
  1703 * replaced "ops" section by extended "consts" section, which is capable of
  1704   handling the continuous function space "->" directly;
  1705 
  1706 * domain package:
  1707   . proves theorems immediately and stores them in the theory,
  1708   . creates hierachical name space,
  1709   . now uses normal mixfix annotations (instead of cinfix...),
  1710   . minor changes to some names and values (for consistency),
  1711   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1712   . separator between mutual domain defs: changed "," to "and",
  1713   . improved handling of sort constraints;  now they have to
  1714     appear on the left-hand side of the equations only;
  1715 
  1716 * fixed LAM <x,y,zs>.b syntax;
  1717 
  1718 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1719 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1720 
  1721 
  1722 *** FOL and ZF ***
  1723 
  1724 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1725   with `addloop' of the simplifier to faciliate case splitting in premises.
  1726 
  1727 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1728 in HOL, they strip ALL and --> from proved theorems;
  1729 
  1730 
  1731 
  1732 New in Isabelle94-8 (May 1997)
  1733 ------------------------------
  1734 
  1735 *** General Changes ***
  1736 
  1737 * new utilities to build / run / maintain Isabelle etc. (in parts
  1738 still somewhat experimental); old Makefiles etc. still functional;
  1739 
  1740 * new 'Isabelle System Manual';
  1741 
  1742 * INSTALL text, together with ./configure and ./build scripts;
  1743 
  1744 * reimplemented type inference for greater efficiency, better error
  1745 messages and clean internal interface;
  1746 
  1747 * prlim command for dealing with lots of subgoals (an easier way of
  1748 setting goals_limit);
  1749 
  1750 
  1751 *** Syntax ***
  1752 
  1753 * supports alternative (named) syntax tables (parser and pretty
  1754 printer); internal interface is provided by add_modesyntax(_i);
  1755 
  1756 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1757 be used in conjunction with the Isabelle symbol font; uses the
  1758 "symbols" syntax table;
  1759 
  1760 * added token_translation interface (may translate name tokens in
  1761 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1762 the current print_mode); IMPORTANT: user print translation functions
  1763 are responsible for marking newly introduced bounds
  1764 (Syntax.mark_boundT);
  1765 
  1766 * token translations for modes "xterm" and "xterm_color" that display
  1767 names in bold, underline etc. or colors (which requires a color
  1768 version of xterm);
  1769 
  1770 * infixes may now be declared with names independent of their syntax;
  1771 
  1772 * added typed_print_translation (like print_translation, but may
  1773 access type of constant);
  1774 
  1775 
  1776 *** Classical Reasoner ***
  1777 
  1778 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1779 some limitations.  Blast_tac...
  1780   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1781   + ignores elimination rules that don't have the correct format
  1782         (the conclusion MUST be a formula variable)
  1783   + ignores types, which can make HOL proofs fail
  1784   + rules must not require higher-order unification, e.g. apply_type in ZF
  1785     [message "Function Var's argument not a bound variable" relates to this]
  1786   + its proof strategy is more general but can actually be slower
  1787 
  1788 * substitution with equality assumptions no longer permutes other
  1789 assumptions;
  1790 
  1791 * minor changes in semantics of addafter (now called addaltern); renamed
  1792 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1793 (and access functions for it);
  1794 
  1795 * improved combination of classical reasoner and simplifier:
  1796   + functions for handling clasimpsets
  1797   + improvement of addss: now the simplifier is called _after_ the
  1798     safe steps.
  1799   + safe variant of addss called addSss: uses safe simplifications
  1800     _during_ the safe steps. It is more complete as it allows multiple
  1801     instantiations of unknowns (e.g. with slow_tac).
  1802 
  1803 *** Simplifier ***
  1804 
  1805 * added interface for simplification procedures (functions that
  1806 produce *proven* rewrite rules on the fly, depending on current
  1807 redex);
  1808 
  1809 * ordering on terms as parameter (used for ordered rewriting);
  1810 
  1811 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1812 
  1813 * the solver is now split into a safe and an unsafe part.
  1814 This should be invisible for the normal user, except that the
  1815 functions setsolver and addsolver have been renamed to setSolver and
  1816 addSolver; added safe_asm_full_simp_tac;
  1817 
  1818 
  1819 *** HOL ***
  1820 
  1821 * a generic induction tactic `induct_tac' which works for all datatypes and
  1822 also for type `nat';
  1823 
  1824 * a generic case distinction tactic `exhaust_tac' which works for all
  1825 datatypes and also for type `nat';
  1826 
  1827 * each datatype comes with a function `size';
  1828 
  1829 * patterns in case expressions allow tuple patterns as arguments to
  1830 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1831 
  1832 * primrec now also works with type nat;
  1833 
  1834 * recdef: a new declaration form, allows general recursive functions to be
  1835 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1836 
  1837 * the constant for negation has been renamed from "not" to "Not" to
  1838 harmonize with FOL, ZF, LK, etc.;
  1839 
  1840 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1841 infinite lists;
  1842 
  1843 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1844 
  1845 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1846 problems in commutative rings, using axiomatic type classes for + and *;
  1847 
  1848 * more examples in HOL/MiniML and HOL/Auth;
  1849 
  1850 * more default rewrite rules for quantifiers, union/intersection;
  1851 
  1852 * a new constant `arbitrary == @x.False';
  1853 
  1854 * HOLCF/IOA replaces old HOL/IOA;
  1855 
  1856 * HOLCF changes: derived all rules and arities
  1857   + axiomatic type classes instead of classes
  1858   + typedef instead of faking type definitions
  1859   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1860   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1861   + eliminated the types void, one, tr
  1862   + use unit lift and bool lift (with translations) instead of one and tr
  1863   + eliminated blift from Lift3.thy (use Def instead of blift)
  1864   all eliminated rules are derived as theorems --> no visible changes ;
  1865 
  1866 
  1867 *** ZF ***
  1868 
  1869 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1870 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1871 as ZF_cs addSIs [equalityI];
  1872 
  1873 
  1874 
  1875 New in Isabelle94-7 (November 96)
  1876 ---------------------------------
  1877 
  1878 * allowing negative levels (as offsets) in prlev and choplev;
  1879 
  1880 * super-linear speedup for large simplifications;
  1881 
  1882 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1883 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1884 FAIL); can suppress it using the command Delsimps (ex_simps @
  1885 all_simps); De Morgan laws are also now included, by default;
  1886 
  1887 * improved printing of ==>  :  ~:
  1888 
  1889 * new object-logic "Sequents" adds linear logic, while replacing LK
  1890 and Modal (thanks to Sara Kalvala);
  1891 
  1892 * HOL/Auth: correctness proofs for authentication protocols;
  1893 
  1894 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1895 examples on HOL/Auth);
  1896 
  1897 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1898 the rewriter and classical reasoner simultaneously;
  1899 
  1900 * function uresult no longer returns theorems in "standard" format;
  1901 regain previous version by: val uresult = standard o uresult;
  1902 
  1903 
  1904 
  1905 New in Isabelle94-6
  1906 -------------------
  1907 
  1908 * oracles -- these establish an interface between Isabelle and trusted
  1909 external reasoners, which may deliver results as theorems;
  1910 
  1911 * proof objects (in particular record all uses of oracles);
  1912 
  1913 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1914 
  1915 * "constdefs" section in theory files;
  1916 
  1917 * "primrec" section (HOL) no longer requires names;
  1918 
  1919 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1920 
  1921 
  1922 
  1923 New in Isabelle94-5
  1924 -------------------
  1925 
  1926 * reduced space requirements;
  1927 
  1928 * automatic HTML generation from theories;
  1929 
  1930 * theory files no longer require "..." (quotes) around most types;
  1931 
  1932 * new examples, including two proofs of the Church-Rosser theorem;
  1933 
  1934 * non-curried (1994) version of HOL is no longer distributed;
  1935 
  1936 
  1937 
  1938 New in Isabelle94-4
  1939 -------------------
  1940 
  1941 * greatly reduced space requirements;
  1942 
  1943 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1944 
  1945 * searchable theorem database (see the section "Retrieving theorems" on
  1946 page 8 of the Reference Manual);
  1947 
  1948 * new examples, including Grabczewski's monumental case study of the
  1949 Axiom of Choice;
  1950 
  1951 * The previous version of HOL renamed to Old_HOL;
  1952 
  1953 * The new version of HOL (previously called CHOL) uses a curried syntax
  1954 for functions.  Application looks like f a b instead of f(a,b);
  1955 
  1956 * Mutually recursive inductive definitions finally work in HOL;
  1957 
  1958 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1959 translates to the operator "split";
  1960 
  1961 
  1962 
  1963 New in Isabelle94-3
  1964 -------------------
  1965 
  1966 * new infix operator, addss, allowing the classical reasoner to
  1967 perform simplification at each step of its search.  Example:
  1968         fast_tac (cs addss ss)
  1969 
  1970 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1971 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1972 look like (a,b) instead of <a,b>;
  1973 
  1974 * PLEASE NOTE: CHOL will eventually replace HOL!
  1975 
  1976 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1977 It translates to the operator "split".  A new theory of integers is available;
  1978 
  1979 * In ZF, integer numerals now denote two's-complement binary integers.
  1980 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1981 
  1982 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1983 of the Axiom of Choice;
  1984 
  1985 
  1986 
  1987 New in Isabelle94-2
  1988 -------------------
  1989 
  1990 * Significantly faster resolution;
  1991 
  1992 * the different sections in a .thy file can now be mixed and repeated
  1993 freely;
  1994 
  1995 * Database of theorems for FOL, HOL and ZF.  New
  1996 commands including qed, qed_goal and bind_thm store theorems in the database.
  1997 
  1998 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1999 a given theory (thms_of), or find out what theory a theorem was proved in
  2000 (theory_of_thm);
  2001 
  2002 * Bugs fixed in the inductive definition and datatype packages;
  2003 
  2004 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2005 and HOL_dup_cs obsolete;
  2006 
  2007 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2008 have been removed;
  2009 
  2010 * Simpler definition of function space in ZF;
  2011 
  2012 * new results about cardinal and ordinal arithmetic in ZF;
  2013 
  2014 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2015 types;
  2016 
  2017 
  2018 $Id$