NEWS
author paulson
Mon Nov 12 12:38:40 2001 +0100 (2001-11-12)
changeset 12159 b3a708ddedf8
parent 12106 4a8558dbb6a0
child 12163 04c98351f9af
permissions -rw-r--r--
ZF/Induct,UNITY
     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 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
    93 now consider the syntactic context of assumptions, giving a better
    94 chance to get type-inference of the arguments right (this is
    95 especially important for locales);
    96 
    97 * Provers: 'simplified' attribute may refer to explicit rules instead
    98 of full simplifier context; 'iff' attribute handles conditional rules;
    99 
   100 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   101 
   102 * HOL: 'recdef' now fails on unfinished automated proofs, use
   103 "(permissive)" option to recover old behavior;
   104 
   105 * HOL: 'inductive' no longer features separate (collective) attributes
   106 for 'intros' (was found too confusing);
   107 
   108 
   109 
   110 *** HOL ***
   111 
   112 * HOL: moved over to sane numeral syntax; the new policy is as
   113 follows:
   114 
   115   - 0 and 1 are polymorphic constants, which are defined on any
   116   numeric type (nat, int, real etc.);
   117 
   118   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   119   binary representation internally;
   120 
   121   - type nat has special constructor Suc, and generally prefers Suc 0
   122   over 1::nat and Suc (Suc 0) over 2::nat;
   123 
   124 This change may cause significant INCOMPATIBILITIES; here are some
   125 hints on converting existing sources:
   126 
   127   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   128   entities, so expressions involving "-" (unary or binary minus) need
   129   to be spaced properly;
   130 
   131   - existing occurrences of "1" may need to be constraint "1::nat" or
   132   even replaced by Suc 0; similar for old "2";
   133 
   134   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   135 
   136   - remove all special provisions on numerals in proofs;
   137 
   138 * HOL/record:
   139   - removed old "make" and "make_scheme" operations -- INCOMPATIBILITY;
   140   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   141   - provides cases/induct rules for use with corresponding Isar methods;
   142   - new derived operations "make" (for adding fields of current
   143     record), "extend" to promote fixed record to record scheme, and
   144     "truncate" for the reverse; cf. theorems "derived_defs", which are
   145     *not* declared as simp by default;
   146   - internal definitions directly based on a light-weight abstract
   147     theory of product types over typedef rather than datatype;
   148 
   149 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   150 
   151 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   152 (beware of argument permutation!);
   153 
   154 * HOL: linorder_less_split superseded by linorder_cases;
   155 
   156 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   157 to peripheral theory "Hilbert_Choice";
   158 
   159 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   160 in this (rare) case use:
   161 
   162   delSWrapper "split_all_tac"
   163   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   164 
   165 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   166 MAY FAIL;
   167 
   168 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   169 Isabelle's type classes, ^ on functions and relations has too general
   170 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   171 necessary to attach explicit type constraints;
   172 
   173 * HOL: syntax translations now work properly with numerals and records
   174 expressions;
   175 
   176 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   177 Florian Kammüller;
   178 
   179 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   180 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   181 renamed "Product_Type.unit";
   182 
   183 
   184 *** HOLCF ***
   185 
   186 * proper rep_datatype lift (see theory Lift); use plain induct_tac
   187 instead of former lift.induct_tac; always use UU instead of Undef;
   188 
   189 * 'domain' package adapted to new-style theories, e.g. see
   190 HOLCF/ex/Dnat.thy;
   191 
   192 
   193 *** ZF ***
   194 
   195 * ZF: the integer library now covers quotients and remainders, with
   196 many laws relating division to addition, multiplication, etc.;
   197 
   198 * ZF/Induct: new directory for examples of inductive definitions, including theory
   199 Multiset for multiset orderings;
   200 
   201 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a typeless
   202 version of the formalism;
   203 
   204 
   205 *** General ***
   206 
   207 * kernel: meta-level proof terms (by Stefan Berghofer), see also ref
   208 manual;
   209 
   210 * Pure/axclass: removed obsolete ML interface goal_subclass/goal_arity;
   211 
   212 * classical: renamed addaltern to addafter, addSaltern to addSafter;
   213 
   214 * clasimp: ``iff'' declarations now handle conditional rules as well;
   215 
   216 * syntax: new token syntax "num" for plain numerals (without "#" of
   217 "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now separate
   218 tokens, so expressions involving minus need to be spaced properly;
   219 
   220 * syntax: support non-oriented infixes;
   221 
   222 * syntax: print modes "type_brackets" and "no_type_brackets" control
   223 output of nested => (types); the default behavior is "type_brackets";
   224 
   225 * syntax: builtin parse translation for "_constify" turns valued
   226 tokens into AST constants;
   227 
   228 * system: refrain from any attempt at filtering input streams; no
   229 longer support ``8bit'' encoding of old isabelle font, instead proper
   230 iso-latin characters may now be used;
   231 
   232 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   233 
   234 * system: Proof General keywords specification is now part of the
   235 Isabelle distribution (see etc/isar-keywords.el);
   236 
   237 * system: smart selection of Isabelle process versus Isabelle
   238 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   239 run both "isabelle" and "Isabelle" even if file names are badly
   240 damaged (executable inspects the case of the first letter of its own
   241 name); added separate "isabelle-process" and "isabelle-interface";
   242 
   243 
   244 
   245 New in Isabelle99-2 (February 2001)
   246 -----------------------------------
   247 
   248 *** Overview of INCOMPATIBILITIES ***
   249 
   250 * HOL: please note that theories in the Library and elsewhere often use the
   251 new-style (Isar) format; to refer to their theorems in an ML script you must
   252 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   253 
   254 * HOL: inductive package no longer splits induction rule aggressively,
   255 but only as far as specified by the introductions given; the old
   256 format may be recovered via ML function complete_split_rule or attribute
   257 'split_rule (complete)';
   258 
   259 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   260 gfp_Tarski to gfp_unfold;
   261 
   262 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   263 
   264 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   265 relation); infix "^^" has been renamed "``"; infix "``" has been
   266 renamed "`"; "univalent" has been renamed "single_valued";
   267 
   268 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   269 operation;
   270 
   271 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   272 
   273 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   274 
   275 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   276 consequence, it is no longer monotonic wrt. the local goal context
   277 (which is now passed through the inductive cases);
   278 
   279 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   280 \<gg> to \<ggreater>;
   281 
   282 
   283 *** Document preparation ***
   284 
   285 * \isabellestyle{NAME} selects version of Isabelle output (currently
   286 available: are "it" for near math-mode best-style output, "sl" for
   287 slanted text style, and "tt" for plain type-writer; if no
   288 \isabellestyle command is given, output is according to slanted
   289 type-writer);
   290 
   291 * support sub/super scripts (for single symbols only), input syntax is
   292 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   293 
   294 * some more standard symbols; see Appendix A of the system manual for
   295 the complete list of symbols defined in isabellesym.sty;
   296 
   297 * improved isabelle style files; more abstract symbol implementation
   298 (should now use \isamath{...} and \isatext{...} in custom symbol
   299 definitions);
   300 
   301 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   302 state; Note that presentation of goal states does not conform to
   303 actual human-readable proof documents.  Please do not include goal
   304 states into document output unless you really know what you are doing!
   305 
   306 * proper indentation of antiquoted output with proportional LaTeX
   307 fonts;
   308 
   309 * no_document ML operator temporarily disables LaTeX document
   310 generation;
   311 
   312 * isatool unsymbolize tunes sources for plain ASCII communication;
   313 
   314 
   315 *** Isar ***
   316 
   317 * Pure: Isar now suffers initial goal statements to contain unbound
   318 schematic variables (this does not conform to actual readable proof
   319 documents, due to unpredictable outcome and non-compositional proof
   320 checking); users who know what they are doing may use schematic goals
   321 for Prolog-style synthesis of proven results;
   322 
   323 * Pure: assumption method (an implicit finishing) now handles actual
   324 rules as well;
   325 
   326 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   327 initial goal, declare "that" only as Pure intro (only for single
   328 steps); the "that" rule assumption may now be involved in implicit
   329 finishing, thus ".." becomes a feasible for trivial obtains;
   330 
   331 * Pure: default proof step now includes 'intro_classes'; thus trivial
   332 instance proofs may be performed by "..";
   333 
   334 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   335 statements as well;
   336 
   337 * Pure: more robust selection of calculational rules;
   338 
   339 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   340 rule (as well as the assumption rule);
   341 
   342 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   343 lemmas, using the graph browser tool;
   344 
   345 * Pure: predict failure of "show" in interactive mode;
   346 
   347 * Pure: 'thms_containing' now takes actual terms as arguments;
   348 
   349 * HOL: improved method 'induct' --- now handles non-atomic goals
   350 (potential INCOMPATIBILITY); tuned error handling;
   351 
   352 * HOL: cases and induct rules now provide explicit hints about the
   353 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   354 any remaining facts are inserted into the goal verbatim;
   355 
   356 * HOL: local contexts (aka cases) may now contain term bindings as
   357 well; the 'cases' and 'induct' methods new provide a ?case binding for
   358 the result to be shown in each case;
   359 
   360 * HOL: added 'recdef_tc' command;
   361 
   362 * isatool convert assists in eliminating legacy ML scripts;
   363 
   364 
   365 *** HOL ***
   366 
   367 * HOL/Library: a collection of generic theories to be used together
   368 with main HOL; the theory loader path already includes this directory
   369 by default; the following existing theories have been moved here:
   370 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   371 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   372 
   373 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   374 modelling and verification task performed in Isabelle/HOL +
   375 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   376 
   377 * HOL/Algebra: special summation operator SUM no longer exists, it has
   378 been replaced by setsum; infix 'assoc' now has priority 50 (like
   379 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   380 'domain', this makes the theory consistent with mathematical
   381 literature;
   382 
   383 * HOL basics: added overloaded operations "inverse" and "divide"
   384 (infix "/"), syntax for generic "abs" operation, generic summation
   385 operator \<Sum>;
   386 
   387 * HOL/typedef: simplified package, provide more useful rules (see also
   388 HOL/subset.thy);
   389 
   390 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   391 now expressed as a proper nested rule (old-style tactic scripts may
   392 require atomize_strip_tac to cope with non-atomic premises);
   393 
   394 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   395 to "split_conv" (old name still available for compatibility);
   396 
   397 * HOL: improved concrete syntax for strings (e.g. allows translation
   398 rules with string literals);
   399 
   400 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   401 and Fleuriot's mechanization of analysis;
   402 
   403 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   404 
   405 
   406 *** CTT ***
   407 
   408 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   409 "lam" is displayed as TWO lambda-symbols
   410 
   411 * CTT: theory Main now available, containing everything (that is, Bool
   412 and Arith);
   413 
   414 
   415 *** General ***
   416 
   417 * Pure: the Simplifier has been implemented properly as a derived rule
   418 outside of the actual kernel (at last!); the overall performance
   419 penalty in practical applications is about 50%, while reliability of
   420 the Isabelle inference kernel has been greatly improved;
   421 
   422 * print modes "brackets" and "no_brackets" control output of nested =>
   423 (types) and ==> (props); the default behaviour is "brackets";
   424 
   425 * Provers: fast_tac (and friends) now handle actual object-logic rules
   426 as assumptions as well;
   427 
   428 * system: support Poly/ML 4.0;
   429 
   430 * system: isatool install handles KDE version 1 or 2;
   431 
   432 
   433 
   434 New in Isabelle99-1 (October 2000)
   435 ----------------------------------
   436 
   437 *** Overview of INCOMPATIBILITIES ***
   438 
   439 * HOL: simplification of natural numbers is much changed; to partly
   440 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   441 issue the following ML commands:
   442 
   443   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   444   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   445 
   446 * HOL: simplification no longer dives into case-expressions; this is
   447 controlled by "t.weak_case_cong" for each datatype t;
   448 
   449 * HOL: nat_less_induct renamed to less_induct;
   450 
   451 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   452 fixsome to patch .thy and .ML sources automatically;
   453 
   454   select_equality  -> some_equality
   455   select_eq_Ex     -> some_eq_ex
   456   selectI2EX       -> someI2_ex
   457   selectI2         -> someI2
   458   selectI          -> someI
   459   select1_equality -> some1_equality
   460   Eps_sym_eq       -> some_sym_eq_trivial
   461   Eps_eq           -> some_eq_trivial
   462 
   463 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   464 
   465 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   466 instead);
   467 
   468 * HOL: the recursion equations generated by 'recdef' are now called
   469 f.simps instead of f.rules;
   470 
   471 * HOL: qed_spec_mp now also handles bounded ALL as well;
   472 
   473 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   474 sometimes be needed;
   475 
   476 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   477 
   478 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   479 
   480 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   481 product is now "<*>" instead of "Times"; the lexicographic product is
   482 now "<*lex*>" instead of "**";
   483 
   484 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   485 of main HOL, but was unused); better use HOL's datatype package;
   486 
   487 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   488 the old syntax may be recovered as follows:
   489 
   490   syntax (symbols)
   491     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   492       (infixl "\\<oplus>" 100)
   493 
   494 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   495 
   496 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   497 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   498 internally;
   499 
   500 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   501 changed from A/r to A//r;
   502 
   503 * ZF: new treatment of arithmetic (nat & int) may break some old
   504 proofs;
   505 
   506 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   507 rulify -> rule_format, elimify -> elim_format, ...);
   508 
   509 * Isar/Provers: intro/elim/dest attributes changed; renamed
   510 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   511 should have to change intro!! to intro? only); replaced "delrule" by
   512 "rule del";
   513 
   514 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   515 
   516 * Provers: strengthened force_tac by using new first_best_tac;
   517 
   518 * LaTeX document preparation: several changes of isabelle.sty (see
   519 lib/texinputs);
   520 
   521 
   522 *** Document preparation ***
   523 
   524 * formal comments (text blocks etc.) in new-style theories may now
   525 contain antiquotations of thm/prop/term/typ/text to be presented
   526 according to latex print mode; concrete syntax is like this:
   527 @{term[show_types] "f(x) = a + x"};
   528 
   529 * isatool mkdir provides easy setup of Isabelle session directories,
   530 including proper document sources;
   531 
   532 * generated LaTeX sources are now deleted after successful run
   533 (isatool document -c); may retain a copy somewhere else via -D option
   534 of isatool usedir;
   535 
   536 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   537 style files, achieving self-contained LaTeX sources and simplifying
   538 LaTeX debugging;
   539 
   540 * old-style theories now produce (crude) LaTeX output as well;
   541 
   542 * browser info session directories are now self-contained (may be put
   543 on WWW server seperately); improved graphs of nested sessions; removed
   544 graph for 'all sessions';
   545 
   546 * several improvements in isabelle style files; \isabellestyle{it}
   547 produces fake math mode output; \isamarkupheader is now \section by
   548 default; see lib/texinputs/isabelle.sty etc.;
   549 
   550 
   551 *** Isar ***
   552 
   553 * Isar/Pure: local results and corresponding term bindings are now
   554 subject to Hindley-Milner polymorphism (similar to ML); this
   555 accommodates incremental type-inference very nicely;
   556 
   557 * Isar/Pure: new derived language element 'obtain' supports
   558 generalized existence reasoning;
   559 
   560 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   561 support accumulation of results, without applying any rules yet;
   562 useful to collect intermediate results without explicit name
   563 references, and for use with transitivity rules with more than 2
   564 premises;
   565 
   566 * Isar/Pure: scalable support for case-analysis type proofs: new
   567 'case' language element refers to local contexts symbolically, as
   568 produced by certain proof methods; internally, case names are attached
   569 to theorems as "tags";
   570 
   571 * Isar/Pure: theory command 'hide' removes declarations from
   572 class/type/const name spaces;
   573 
   574 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   575 indicate potential overloading;
   576 
   577 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   578 
   579 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   580 "{a,b,c}" instead of {a,b,c};
   581 
   582 * Isar/Pure now provides its own version of intro/elim/dest
   583 attributes; useful for building new logics, but beware of confusion
   584 with the version in Provers/classical;
   585 
   586 * Isar/Pure: the local context of (non-atomic) goals is provided via
   587 case name 'antecedent';
   588 
   589 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   590 to the current context is now done automatically);
   591 
   592 * Isar/Pure: theory command 'method_setup' provides a simple interface
   593 for definining proof methods in ML;
   594 
   595 * Isar/Provers: intro/elim/dest attributes changed; renamed
   596 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   597 most cases, one should have to change intro!! to intro? only);
   598 replaced "delrule" by "rule del";
   599 
   600 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   601 'symmetric' attribute (the latter supercedes [RS sym]);
   602 
   603 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   604 method modifier); 'simp' method: 'only:' modifier removes loopers as
   605 well (including splits);
   606 
   607 * Isar/Provers: Simplifier and Classical methods now support all kind
   608 of modifiers used in the past, including 'cong', 'iff', etc.
   609 
   610 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   611 of Simplifier and Classical reasoner);
   612 
   613 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   614 now support named cases; major packages (inductive, datatype, primrec,
   615 recdef) support case names and properly name parameters;
   616 
   617 * Isar/HOL: new transitivity rules for substitution in inequalities --
   618 monotonicity conditions are extracted to be proven at end of
   619 calculations;
   620 
   621 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   622 method anyway;
   623 
   624 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   625 split_if split_if_asm; datatype package provides theorems foo.splits =
   626 foo.split foo.split_asm for each datatype;
   627 
   628 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   629 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   630 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   631 use "(cases (simplified))" method in proper proof texts);
   632 
   633 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   634 
   635 * Isar: names of theorems etc. may be natural numbers as well;
   636 
   637 * Isar: 'pr' command: optional arguments for goals_limit and
   638 ProofContext.prems_limit; no longer prints theory contexts, but only
   639 proof states;
   640 
   641 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   642 additional print modes to be specified; e.g. "pr(latex)" will print
   643 proof state according to the Isabelle LaTeX style;
   644 
   645 * Isar: improved support for emulating tactic scripts, including proof
   646 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   647 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   648 (for HOL datatypes);
   649 
   650 * Isar: simplified (more robust) goal selection of proof methods: 1st
   651 goal, all goals, or explicit goal specifier (tactic emulation); thus
   652 'proof method scripts' have to be in depth-first order;
   653 
   654 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   655 
   656 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   657 should instead use individual commands for printing items
   658 (print_commands, print_methods etc.);
   659 
   660 * Isar: added 'nothing' --- the empty list of theorems;
   661 
   662 
   663 *** HOL ***
   664 
   665 * HOL/MicroJava: formalization of a fragment of Java, together with a
   666 corresponding virtual machine and a specification of its bytecode
   667 verifier and a lightweight bytecode verifier, including proofs of
   668 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   669 Cornelia Pusch (see also the homepage of project Bali at
   670 http://isabelle.in.tum.de/Bali/);
   671 
   672 * HOL/Algebra: new theory of rings and univariate polynomials, by
   673 Clemens Ballarin;
   674 
   675 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   676 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   677 Rasmussen;
   678 
   679 * HOL/Lattice: fundamental concepts of lattice theory and order
   680 structures, including duals, properties of bounds versus algebraic
   681 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   682 Theorem for complete lattices etc.; may also serve as a demonstration
   683 for abstract algebraic reasoning using axiomatic type classes, and
   684 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   685 
   686 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   687 von Oheimb;
   688 
   689 * HOL/IMPP: extension of IMP with local variables and mutually
   690 recursive procedures, by David von Oheimb;
   691 
   692 * HOL/Lambda: converted into new-style theory and document;
   693 
   694 * HOL/ex/Multiquote: example of multiple nested quotations and
   695 anti-quotations -- basically a generalized version of de-Bruijn
   696 representation; very useful in avoiding lifting of operations;
   697 
   698 * HOL/record: added general record equality rule to simpset; fixed
   699 select-update simplification procedure to handle extended records as
   700 well; admit "r" as field name;
   701 
   702 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   703 other numeric types and also as the identity of groups, rings, etc.;
   704 
   705 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   706 Types nat and int belong to this axclass;
   707 
   708 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   709    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   710    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   711   two terms #m*u and #n*u are replaced by #(m+n)*u
   712     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   713   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   714     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   715 
   716 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   717 powerful prover for predicate logic but knows nothing of clasets; see
   718 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   719 
   720 * HOL: new version of "case_tac" subsumes both boolean case split and
   721 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   722 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   723 
   724 * HOL: simplification no longer dives into case-expressions: only the
   725 selector expression is simplified, but not the remaining arms; to
   726 enable full simplification of case-expressions for datatype t, you may
   727 remove t.weak_case_cong from the simpset, either globally (Delcongs
   728 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   729 
   730 * HOL/recdef: the recursion equations generated by 'recdef' for
   731 function 'f' are now called f.simps instead of f.rules; if all
   732 termination conditions are proved automatically, these simplification
   733 rules are added to the simpset, as in primrec; rules may be named
   734 individually as well, resulting in a separate list of theorems for
   735 each equation;
   736 
   737 * HOL/While is a new theory that provides a while-combinator. It
   738 permits the definition of tail-recursive functions without the
   739 provision of a termination measure. The latter is necessary once the
   740 invariant proof rule for while is applied.
   741 
   742 * HOL: new (overloaded) notation for the set of elements below/above
   743 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   744 
   745 * HOL: theorems impI, allI, ballI bound as "strip";
   746 
   747 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   748 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   749 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   750 
   751 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   752 
   753 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   754 main HOL, but was unused);
   755 
   756 * HOL: fewer consts declared as global (e.g. have to refer to
   757 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   758 
   759 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   760 in case of overlap with user translations (e.g. judgements over
   761 tuples); (note that the underlying logical represenation is still
   762 bogus);
   763 
   764 
   765 *** ZF ***
   766 
   767 * ZF: simplification automatically cancels common terms in arithmetic
   768 expressions over nat and int;
   769 
   770 * ZF: new treatment of nat to minimize type-checking: all operators
   771 coerce their operands to a natural number using the function natify,
   772 making the algebraic laws unconditional;
   773 
   774 * ZF: as above, for int: operators coerce their operands to an integer
   775 using the function intify;
   776 
   777 * ZF: the integer library now contains many of the usual laws for the
   778 orderings, including $<=, and monotonicity laws for $+ and $*;
   779 
   780 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   781 simplification;
   782 
   783 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   784 to the simplifier and classical reasoner simultaneously;
   785 
   786 
   787 *** General ***
   788 
   789 * Provers: blast_tac now handles actual object-logic rules as
   790 assumptions; note that auto_tac uses blast_tac internally as well;
   791 
   792 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   793 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   794 
   795 * Provers: delrules now handles destruct rules as well (no longer need
   796 explicit make_elim);
   797 
   798 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   799   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   800 use instead the strong form,
   801   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   802 in HOL, FOL and ZF the function cla_make_elim will create such rules
   803 from destruct-rules;
   804 
   805 * Provers: Simplifier.easy_setup provides a fast path to basic
   806 Simplifier setup for new object-logics;
   807 
   808 * Pure: AST translation rules no longer require constant head on LHS;
   809 
   810 * Pure: improved name spaces: ambiguous output is qualified; support
   811 for hiding of names;
   812 
   813 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   814 XSYMBOL_HOME; no longer need to do manual configuration in most
   815 situations;
   816 
   817 * system: compression of ML heaps images may now be controlled via -c
   818 option of isabelle and isatool usedir (currently only observed by
   819 Poly/ML);
   820 
   821 * system: isatool installfonts may handle X-Symbol fonts as well (very
   822 useful for remote X11);
   823 
   824 * system: provide TAGS file for Isabelle sources;
   825 
   826 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   827 order;
   828 
   829 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   830 timing flag supersedes proof_timing and Toplevel.trace;
   831 
   832 * ML: new combinators |>> and |>>> for incremental transformations
   833 with secondary results (e.g. certain theory extensions):
   834 
   835 * ML: PureThy.add_defs gets additional argument to indicate potential
   836 overloading (usually false);
   837 
   838 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   839 results;
   840 
   841 
   842 
   843 New in Isabelle99 (October 1999)
   844 --------------------------------
   845 
   846 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   847 
   848 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   849 are no longer simplified.  (This allows the simplifier to unfold recursive
   850 functional programs.)  To restore the old behaviour, declare
   851 
   852     Delcongs [if_weak_cong];
   853 
   854 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   855 complement;
   856 
   857 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   858 
   859 * HOL/datatype: mutual_induct_tac no longer exists --
   860   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   861 
   862 * HOL/typedef: fixed type inference for representing set; type
   863 arguments now have to occur explicitly on the rhs as type constraints;
   864 
   865 * ZF: The con_defs part of an inductive definition may no longer refer
   866 to constants declared in the same theory;
   867 
   868 * HOL, ZF: the function mk_cases, generated by the inductive
   869 definition package, has lost an argument.  To simplify its result, it
   870 uses the default simpset instead of a supplied list of theorems.
   871 
   872 * HOL/List: the constructors of type list are now Nil and Cons;
   873 
   874 * Simplifier: the type of the infix ML functions
   875         setSSolver addSSolver setSolver addSolver
   876 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   877 for packaging solvers. A solver is created via
   878         mk_solver: string -> (thm list -> int -> tactic) -> solver
   879 where the string argument is only a comment.
   880 
   881 
   882 *** Proof tools ***
   883 
   884 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   885 decision procedure for linear arithmetic. Currently it is used for
   886 types `nat', `int', and `real' in HOL (see below); it can, should and
   887 will be instantiated for other types and logics as well.
   888 
   889 * The simplifier now accepts rewrite rules with flexible heads, eg
   890      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   891   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   892   matching.
   893 
   894 
   895 *** General ***
   896 
   897 * New Isabelle/Isar subsystem provides an alternative to traditional
   898 tactical theorem proving; together with the ProofGeneral/isar user
   899 interface it offers an interactive environment for developing human
   900 readable proof documents (Isar == Intelligible semi-automated
   901 reasoning); for further information see isatool doc isar-ref,
   902 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   903 
   904 * improved and simplified presentation of theories: better HTML markup
   905 (including colors), graph views in several sizes; isatool usedir now
   906 provides a proper interface for user theories (via -P option); actual
   907 document preparation based on (PDF)LaTeX is available as well (for
   908 new-style theories only); see isatool doc system for more information;
   909 
   910 * native support for Proof General, both for classic Isabelle and
   911 Isabelle/Isar;
   912 
   913 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   914 using the graph browser tool;
   915 
   916 * Isabelle manuals now also available as PDF;
   917 
   918 * theory loader rewritten from scratch (may not be fully
   919 bug-compatible); old loadpath variable has been replaced by show_path,
   920 add_path, del_path, reset_path functions; new operations such as
   921 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   922 isatool doc ref);
   923 
   924 * improved isatool install: option -k creates KDE application icon,
   925 option -p DIR installs standalone binaries;
   926 
   927 * added ML_PLATFORM setting (useful for cross-platform installations);
   928 more robust handling of platform specific ML images for SML/NJ;
   929 
   930 * the settings environment is now statically scoped, i.e. it is never
   931 created again in sub-processes invoked from isabelle, isatool, or
   932 Isabelle;
   933 
   934 * path element specification '~~' refers to '$ISABELLE_HOME';
   935 
   936 * in locales, the "assumes" and "defines" parts may be omitted if
   937 empty;
   938 
   939 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   940 long arrows);
   941 
   942 * new print_mode "HTML";
   943 
   944 * new flag show_tags controls display of tags of theorems (which are
   945 basically just comments that may be attached by some tools);
   946 
   947 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   948 mode and goal output format:
   949 
   950 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   951 244c244
   952 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   953 ---
   954 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   955 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   956 181c181
   957 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   958 ---
   959 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   960 
   961 * function bind_thms stores lists of theorems (cf. bind_thm);
   962 
   963 * new shorthand tactics ftac, eatac, datac, fatac;
   964 
   965 * qed (and friends) now accept "" as result name; in that case the
   966 theorem is not stored, but proper checks and presentation of the
   967 result still apply;
   968 
   969 * theorem database now also indexes constants "Trueprop", "all",
   970 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   971 
   972 
   973 *** HOL ***
   974 
   975 ** HOL arithmetic **
   976 
   977 * There are now decision procedures for linear arithmetic over nat and
   978 int:
   979 
   980 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   981 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   982 are treated as atomic; subformulae not involving type `nat' or `int'
   983 are ignored; quantified subformulae are ignored unless they are
   984 positive universal or negative existential. The tactic has to be
   985 invoked by hand and can be a little bit slow. In particular, the
   986 running time is exponential in the number of occurrences of `min' and
   987 `max', and `-' on `nat'.
   988 
   989 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   990 (negated) (in)equalities among the premises and the conclusion into
   991 account (i.e. no compound formulae) and does not know about `min' and
   992 `max', and `-' on `nat'. It is fast and is used automatically by the
   993 simplifier.
   994 
   995 NB: At the moment, these decision procedures do not cope with mixed
   996 nat/int formulae where the two parts interact, such as `m < n ==>
   997 int(m) < int(n)'.
   998 
   999 * HOL/Numeral provides a generic theory of numerals (encoded
  1000 efficiently as bit strings); setup for types nat/int/real is in place;
  1001 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1002 int, existing theories and proof scripts may require a few additional
  1003 type constraints;
  1004 
  1005 * integer division and remainder can now be performed on constant
  1006 arguments;
  1007 
  1008 * many properties of integer multiplication, division and remainder
  1009 are now available;
  1010 
  1011 * An interface to the Stanford Validity Checker (SVC) is available through the
  1012 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1013 are proved automatically.  SVC must be installed separately, and its results
  1014 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1015 invocation of the underlying oracle).  For SVC see
  1016   http://verify.stanford.edu/SVC
  1017 
  1018 * IsaMakefile: the HOL-Real target now builds an actual image;
  1019 
  1020 
  1021 ** HOL misc **
  1022 
  1023 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1024 (in Isabelle/Isar) -- by Gertrud Bauer;
  1025 
  1026 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1027 analysis for assembly languages with subtypes;
  1028 
  1029 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1030 -- avoids syntactic ambiguities and treats state, transition, and
  1031 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1032 changed syntax and (many) tactics;
  1033 
  1034 * HOL/inductive: Now also handles more general introduction rules such
  1035   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1036   theorems are now maintained within the theory (maintained via the
  1037   "mono" attribute);
  1038 
  1039 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1040   (using function types) such as
  1041 
  1042   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1043 
  1044 * HOL/record: record_simproc (part of the default simpset) takes care
  1045 of selectors applied to updated records; record_split_tac is no longer
  1046 part of the default claset; update_defs may now be removed from the
  1047 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1048 
  1049   claset_ref () := claset() addSWrapper record_split_wrapper;
  1050   Delsimprocs [record_simproc]
  1051 
  1052 * HOL/typedef: fixed type inference for representing set; type
  1053 arguments now have to occur explicitly on the rhs as type constraints;
  1054 
  1055 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1056 names rather than an ML expression;
  1057 
  1058 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1059 supplied later.  Program schemes can be defined, such as
  1060     "While B C s = (if B s then While B C (C s) else s)"
  1061 where the well-founded relation can be chosen after B and C have been given.
  1062 
  1063 * HOL/List: the constructors of type list are now Nil and Cons;
  1064 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1065 course, ML tools referring to List.list.op # etc. have to be adapted;
  1066 
  1067 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1068 disabled by default; run isabelle with option -m HOL to get back to
  1069 the original Gordon/HOL-style output;
  1070 
  1071 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1072 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1073 
  1074 * HOL basic syntax simplified (more orthogonal): all variants of
  1075 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1076 Eps operator is provided as well: "SOME x. P[x]";
  1077 
  1078 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1079 
  1080 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1081 thus available for user theories;
  1082 
  1083 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1084 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1085 time;
  1086 
  1087 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1088 several times and then mp;
  1089 
  1090 
  1091 *** LK ***
  1092 
  1093 * the notation <<...>> is now available as a notation for sequences of
  1094 formulas;
  1095 
  1096 * the simplifier is now installed
  1097 
  1098 * the axiom system has been generalized (thanks to Soren Heilmann)
  1099 
  1100 * the classical reasoner now has a default rule database
  1101 
  1102 
  1103 *** ZF ***
  1104 
  1105 * new primrec section allows primitive recursive functions to be given
  1106 directly (as in HOL) over datatypes and the natural numbers;
  1107 
  1108 * new tactics induct_tac and exhaust_tac for induction (or case
  1109 analysis) over datatypes and the natural numbers;
  1110 
  1111 * the datatype declaration of type T now defines the recursor T_rec;
  1112 
  1113 * simplification automatically does freeness reasoning for datatype
  1114 constructors;
  1115 
  1116 * automatic type-inference, with AddTCs command to insert new
  1117 type-checking rules;
  1118 
  1119 * datatype introduction rules are now added as Safe Introduction rules
  1120 to the claset;
  1121 
  1122 * the syntax "if P then x else y" is now available in addition to
  1123 if(P,x,y);
  1124 
  1125 
  1126 *** Internal programming interfaces ***
  1127 
  1128 * tuned simplifier trace output; new flag debug_simp;
  1129 
  1130 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1131 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1132 
  1133 * AxClass.axclass_tac lost the theory argument;
  1134 
  1135 * tuned current_goals_markers semantics: begin / end goal avoids
  1136 printing empty lines;
  1137 
  1138 * removed prs and prs_fn hook, which was broken because it did not
  1139 include \n in its semantics, forcing writeln to add one
  1140 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1141 string -> unit if you really want to output text without newline;
  1142 
  1143 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1144 plain output, interface builders may have to enable 'isabelle_font'
  1145 mode to get Isabelle font glyphs as before;
  1146 
  1147 * refined token_translation interface; INCOMPATIBILITY: output length
  1148 now of type real instead of int;
  1149 
  1150 * theory loader actions may be traced via new ThyInfo.add_hook
  1151 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1152 your own database of information attached to *whole* theories -- as
  1153 opposed to intra-theory data slots offered via TheoryDataFun;
  1154 
  1155 * proper handling of dangling sort hypotheses (at last!);
  1156 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1157 extra sort hypotheses that can be witnessed from the type signature;
  1158 the force_strip_shyps flag is gone, any remaining shyps are simply
  1159 left in the theorem (with a warning issued by strip_shyps_warning);
  1160 
  1161 
  1162 
  1163 New in Isabelle98-1 (October 1998)
  1164 ----------------------------------
  1165 
  1166 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1167 
  1168 * several changes of automated proof tools;
  1169 
  1170 * HOL: major changes to the inductive and datatype packages, including
  1171 some minor incompatibilities of theory syntax;
  1172 
  1173 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1174 called `inj_on';
  1175 
  1176 * HOL: removed duplicate thms in Arith:
  1177   less_imp_add_less  should be replaced by  trans_less_add1
  1178   le_imp_add_le      should be replaced by  trans_le_add1
  1179 
  1180 * HOL: unary minus is now overloaded (new type constraints may be
  1181 required);
  1182 
  1183 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1184 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1185 now taken as an integer constant.
  1186 
  1187 * Pure: ML function 'theory_of' renamed to 'theory';
  1188 
  1189 
  1190 *** Proof tools ***
  1191 
  1192 * Simplifier:
  1193   1. Asm_full_simp_tac is now more aggressive.
  1194      1. It will sometimes reorient premises if that increases their power to
  1195         simplify.
  1196      2. It does no longer proceed strictly from left to right but may also
  1197         rotate premises to achieve further simplification.
  1198      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1199      old Asm_full_simp_tac in that it does not rotate premises.
  1200   2. The simplifier now knows a little bit about nat-arithmetic.
  1201 
  1202 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1203 allows for selected deletion of wrappers, by introduction of names for
  1204 wrapper functionals.  This implies that addbefore, addSbefore,
  1205 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1206 and that adding two tactics with the same name overwrites the first
  1207 one (emitting a warning).
  1208   type wrapper = (int -> tactic) -> (int -> tactic)
  1209   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1210   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1211   delWrapper, delSWrapper: claset *  string            -> claset
  1212   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1213 
  1214 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1215 semantics; addbefore now affects only the unsafe part of step_tac
  1216 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1217 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1218 by Force_tac;
  1219 
  1220 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1221 compWrapper; added safe wrapper (and access functions for it);
  1222 
  1223 * HOL/split_all_tac is now much faster and fails if there is nothing
  1224 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1225 and the names of the automatically generated variables have changed.
  1226 split_all_tac has moved within claset() from unsafe wrappers to safe
  1227 wrappers, which means that !!-bound variables are split much more
  1228 aggressively, and safe_tac and clarify_tac now split such variables.
  1229 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1230 Note: the same holds for record_split_tac, which does the job of
  1231 split_all_tac for record fields.
  1232 
  1233 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1234 permanently to the default simpset using Addsplits just like
  1235 Addsimps. They can be removed via Delsplits just like
  1236 Delsimps. Lower-case versions are also available.
  1237 
  1238 * HOL/Simplifier: The rule split_if is now part of the default
  1239 simpset. This means that the simplifier will eliminate all occurrences
  1240 of if-then-else in the conclusion of a goal. To prevent this, you can
  1241 either remove split_if completely from the default simpset by
  1242 `Delsplits [split_if]' or remove it in a specific call of the
  1243 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1244 other case splitting rules to/from the default simpset: every datatype
  1245 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1246 t is the name of the datatype).
  1247 
  1248 * Classical reasoner / Simplifier combination: new force_tac (and
  1249 derivatives Force_tac, force) combines rewriting and classical
  1250 reasoning (and whatever other tools) similarly to auto_tac, but is
  1251 aimed to solve the given subgoal completely.
  1252 
  1253 
  1254 *** General ***
  1255 
  1256 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1257 and `goalw': the theory is no longer needed as an explicit argument -
  1258 the current theory context is used; assumptions are no longer returned
  1259 at the ML-level unless one of them starts with ==> or !!; it is
  1260 recommended to convert to these new commands using isatool fixgoal
  1261 (backup your sources first!);
  1262 
  1263 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1264 the current theory context, and 'theory' to lookup stored theories;
  1265 
  1266 * new theory section 'locale' for declaring constants, assumptions and
  1267 definitions that have local scope;
  1268 
  1269 * new theory section 'nonterminals' for purely syntactic types;
  1270 
  1271 * new theory section 'setup' for generic ML setup functions
  1272 (e.g. package initialization);
  1273 
  1274 * the distribution now includes Isabelle icons: see
  1275 lib/logo/isabelle-{small,tiny}.xpm;
  1276 
  1277 * isatool install - install binaries with absolute references to
  1278 ISABELLE_HOME/bin;
  1279 
  1280 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1281 
  1282 * print mode 'emacs' reserved for Isamode;
  1283 
  1284 * support multiple print (ast) translations per constant name;
  1285 
  1286 * theorems involving oracles are now printed with a suffixed [!];
  1287 
  1288 
  1289 *** HOL ***
  1290 
  1291 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1292 
  1293 * HOL/inductive package reorganized and improved: now supports mutual
  1294 definitions such as
  1295 
  1296   inductive EVEN ODD
  1297     intrs
  1298       null "0 : EVEN"
  1299       oddI "n : EVEN ==> Suc n : ODD"
  1300       evenI "n : ODD ==> Suc n : EVEN"
  1301 
  1302 new theorem list "elims" contains an elimination rule for each of the
  1303 recursive sets; inductive definitions now handle disjunctive premises
  1304 correctly (also ZF);
  1305 
  1306 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1307 "mutual_induct" no longer exists - the induction rule is always
  1308 contained in "induct";
  1309 
  1310 
  1311 * HOL/datatype package re-implemented and greatly improved: now
  1312 supports mutually recursive datatypes such as
  1313 
  1314   datatype
  1315     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1316             | SUM ('a aexp) ('a aexp)
  1317             | DIFF ('a aexp) ('a aexp)
  1318             | NUM 'a
  1319   and
  1320     'a bexp = LESS ('a aexp) ('a aexp)
  1321             | AND ('a bexp) ('a bexp)
  1322             | OR ('a bexp) ('a bexp)
  1323 
  1324 as well as indirectly recursive datatypes such as
  1325 
  1326   datatype
  1327     ('a, 'b) term = Var 'a
  1328                   | App 'b ((('a, 'b) term) list)
  1329 
  1330 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1331 induction on mutually / indirectly recursive datatypes.
  1332 
  1333 Primrec equations are now stored in theory and can be accessed via
  1334 <function_name>.simps.
  1335 
  1336 INCOMPATIBILITIES:
  1337 
  1338   - Theories using datatypes must now have theory Datatype as an
  1339     ancestor.
  1340   - The specific <typename>.induct_tac no longer exists - use the
  1341     generic induct_tac instead.
  1342   - natE has been renamed to nat.exhaust - use exhaust_tac
  1343     instead of res_inst_tac ... natE. Note that the variable
  1344     names in nat.exhaust differ from the names in natE, this
  1345     may cause some "fragile" proofs to fail.
  1346   - The theorems split_<typename>_case and split_<typename>_case_asm
  1347     have been renamed to <typename>.split and <typename>.split_asm.
  1348   - Since default sorts of type variables are now handled correctly,
  1349     some datatype definitions may have to be annotated with explicit
  1350     sort constraints.
  1351   - Primrec definitions no longer require function name and type
  1352     of recursive argument.
  1353 
  1354 Consider using isatool fixdatatype to adapt your theories and proof
  1355 scripts to the new package (backup your sources first!).
  1356 
  1357 
  1358 * HOL/record package: considerably improved implementation; now
  1359 includes concrete syntax for record types, terms, updates; theorems
  1360 for surjective pairing and splitting !!-bound record variables; proof
  1361 support is as follows:
  1362 
  1363   1) standard conversions (selectors or updates applied to record
  1364 constructor terms) are part of the standard simpset;
  1365 
  1366   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1367 made part of standard simpset and claset via addIffs;
  1368 
  1369   3) a tactic for record field splitting (record_split_tac) is part of
  1370 the standard claset (addSWrapper);
  1371 
  1372 To get a better idea about these rules you may retrieve them via
  1373 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1374 the name of your record type.
  1375 
  1376 The split tactic 3) conceptually simplifies by the following rule:
  1377 
  1378   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1379 
  1380 Thus any record variable that is bound by meta-all will automatically
  1381 blow up into some record constructor term, consequently the
  1382 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1383 solve record problems automatically.
  1384 
  1385 
  1386 * reorganized the main HOL image: HOL/Integ and String loaded by
  1387 default; theory Main includes everything;
  1388 
  1389 * automatic simplification of integer sums and comparisons, using cancellation;
  1390 
  1391 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1392 
  1393 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1394 
  1395 * many new identities for unions, intersections, set difference, etc.;
  1396 
  1397 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1398 called split_if, split_split, split_sum_case and split_nat_case (to go
  1399 with add/delsplits);
  1400 
  1401 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1402 (?x::unit) = (); this is made part of the default simpset, which COULD
  1403 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1404 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1405 unit_abs_eta_conv is added in order to counter the effect of
  1406 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1407 %u.f();
  1408 
  1409 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1410 makes more sense);
  1411 
  1412 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1413   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1414   disjointness reasoning but breaking a few old proofs.
  1415 
  1416 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1417 to 'converse' from 'inverse' (for compatibility with ZF and some
  1418 literature);
  1419 
  1420 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1421 the well-founded relation;
  1422 
  1423 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1424     Compl A.  The "Compl" syntax remains available as input syntax for this
  1425     release ONLY.
  1426 
  1427 * HOL/Update: new theory of function updates:
  1428     f(a:=b) == %x. if x=a then b else f x
  1429 may also be iterated as in f(a:=b,c:=d,...);
  1430 
  1431 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1432 
  1433 * HOL/List:
  1434   - new function list_update written xs[i:=v] that updates the i-th
  1435     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1436   - new function `upt' written [i..j(] which generates the list
  1437     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1438     bound write [i..j], which is a shorthand for [i..j+1(].
  1439   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1440 
  1441 * HOL/Arith:
  1442   - removed 'pred' (predecessor) function;
  1443   - generalized some theorems about n-1;
  1444   - many new laws about "div" and "mod";
  1445   - new laws about greatest common divisors (see theory ex/Primes);
  1446 
  1447 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1448 instead of "inverse";
  1449 
  1450 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1451   of the multiset ordering;
  1452 
  1453 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1454   (not included by default);
  1455 
  1456 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1457 
  1458 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1459   programs, i.e. different program variables may have different types.
  1460 
  1461 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1462   [previously, this check worked only if the rewrite rule was unconditional]
  1463   Now rew can involve either definitions or equalities (either == or =).
  1464 
  1465 
  1466 *** ZF ***
  1467 
  1468 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1469   only the theorems proved on ZF.ML;
  1470 
  1471 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1472   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1473   disjointness reasoning but breaking a few old proofs.
  1474 
  1475 * ZF/Update: new theory of function updates
  1476     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1477   may also be iterated as in f(a:=b,c:=d,...);
  1478 
  1479 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1480 
  1481 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1482   [previously, this check worked only if the rewrite rule was unconditional]
  1483   Now rew can involve either definitions or equalities (either == or =).
  1484 
  1485 * case_tac provided for compatibility with HOL
  1486     (like the old excluded_middle_tac, but with subgoals swapped)
  1487 
  1488 
  1489 *** Internal programming interfaces ***
  1490 
  1491 * Pure: several new basic modules made available for general use, see
  1492 also src/Pure/README;
  1493 
  1494 * improved the theory data mechanism to support encapsulation (data
  1495 kind name replaced by private Object.kind, acting as authorization
  1496 key); new type-safe user interface via functor TheoryDataFun; generic
  1497 print_data function becomes basically useless;
  1498 
  1499 * removed global_names compatibility flag -- all theory declarations
  1500 are qualified by default;
  1501 
  1502 * module Pure/Syntax now offers quote / antiquote translation
  1503 functions (useful for Hoare logic etc. with implicit dependencies);
  1504 see HOL/ex/Antiquote for an example use;
  1505 
  1506 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1507 cterm -> thm;
  1508 
  1509 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1510 subgoal;
  1511 
  1512 * Display.print_goals function moved to Locale.print_goals;
  1513 
  1514 * standard print function for goals supports current_goals_markers
  1515 variable for marking begin of proof, end of proof, start of goal; the
  1516 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1517 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1518 for example;
  1519 
  1520 
  1521 
  1522 New in Isabelle98 (January 1998)
  1523 --------------------------------
  1524 
  1525 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1526 
  1527 * changed lexical syntax of terms / types: dots made part of long
  1528 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1529 
  1530 * simpset (and claset) reference variable replaced by functions
  1531 simpset / simpset_ref;
  1532 
  1533 * no longer supports theory aliases (via merge) and non-trivial
  1534 implicit merge of thms' signatures;
  1535 
  1536 * most internal names of constants changed due to qualified names;
  1537 
  1538 * changed Pure/Sequence interface (see Pure/seq.ML);
  1539 
  1540 
  1541 *** General Changes ***
  1542 
  1543 * hierachically structured name spaces (for consts, types, axms, thms
  1544 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1545 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1546 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1547 long_names for fully qualified output names; NOTE: ML programs
  1548 (special tactics, packages etc.) referring to internal names may have
  1549 to be adapted to cope with fully qualified names; in case of severe
  1550 backward campatibility problems try setting 'global_names' at compile
  1551 time to have enrything declared within a flat name space; one may also
  1552 fine tune name declarations in theories via the 'global' and 'local'
  1553 section;
  1554 
  1555 * reimplemented the implicit simpset and claset using the new anytype
  1556 data filed in signatures; references simpset:simpset ref etc. are
  1557 replaced by functions simpset:unit->simpset and
  1558 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1559 to patch your ML files accordingly;
  1560 
  1561 * HTML output now includes theory graph data for display with Java
  1562 applet or isatool browser; data generated automatically via isatool
  1563 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1564 
  1565 * defs may now be conditional; improved rewrite_goals_tac to handle
  1566 conditional equations;
  1567 
  1568 * defs now admits additional type arguments, using TYPE('a) syntax;
  1569 
  1570 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1571 creates a new theory node; implicit merge of thms' signatures is
  1572 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1573 transfer:theory->thm->thm in (rare) cases;
  1574 
  1575 * improved handling of draft signatures / theories; draft thms (and
  1576 ctyps, cterms) are automatically promoted to real ones;
  1577 
  1578 * slightly changed interfaces for oracles: admit many per theory, named
  1579 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1580 
  1581 * print_goals: optional output of const types (set show_consts and
  1582 show_types);
  1583 
  1584 * improved output of warnings (###) and errors (***);
  1585 
  1586 * subgoal_tac displays a warning if the new subgoal has type variables;
  1587 
  1588 * removed old README and Makefiles;
  1589 
  1590 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1591 
  1592 * removed obsolete init_pps and init_database;
  1593 
  1594 * deleted the obsolete tactical STATE, which was declared by
  1595     fun STATE tacfun st = tacfun st st;
  1596 
  1597 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1598 (which abbreviates $HOME);
  1599 
  1600 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1601 use isatool fixseq to adapt your ML programs (this works for fully
  1602 qualified references to the Sequence structure only!);
  1603 
  1604 * use_thy no longer requires writable current directory; it always
  1605 reloads .ML *and* .thy file, if either one is out of date;
  1606 
  1607 
  1608 *** Classical Reasoner ***
  1609 
  1610 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1611 tactics that use classical reasoning to simplify a subgoal without
  1612 splitting it into several subgoals;
  1613 
  1614 * Safe_tac: like safe_tac but uses the default claset;
  1615 
  1616 
  1617 *** Simplifier ***
  1618 
  1619 * added simplification meta rules:
  1620     (asm_)(full_)simplify: simpset -> thm -> thm;
  1621 
  1622 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1623 logics (again);
  1624 
  1625 * added prems argument to simplification procedures;
  1626 
  1627 * HOL, FOL, ZF: added infix function `addsplits':
  1628   instead of `<simpset> setloop (split_tac <thms>)'
  1629   you can simply write `<simpset> addsplits <thms>'
  1630 
  1631 
  1632 *** Syntax ***
  1633 
  1634 * TYPE('a) syntax for type reflection terms;
  1635 
  1636 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1637 
  1638 * pretty printer: changed order of mixfix annotation preference (again!);
  1639 
  1640 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1641 
  1642 
  1643 *** HOL ***
  1644 
  1645 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1646   with `addloop' of the simplifier to faciliate case splitting in premises.
  1647 
  1648 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1649 
  1650 * HOL/Auth: new protocol proofs including some for the Internet
  1651   protocol TLS;
  1652 
  1653 * HOL/Map: new theory of `maps' a la VDM;
  1654 
  1655 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1656 cancelling out common nat summands from =, <, <= (in)equalities, or
  1657 differences; simplification procedures nat_cancel_factor for
  1658 cancelling common factor from =, <, <= (in)equalities over natural
  1659 sums; nat_cancel contains both kinds of procedures, it is installed by
  1660 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1661 
  1662 * HOL/simplifier: terms of the form
  1663   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1664   are rewritten to
  1665   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1666   and those of the form
  1667   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1668   are rewritten to
  1669   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1670 
  1671 * HOL/datatype
  1672   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1673 
  1674   P(t_case f1 ... fn x) =
  1675      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1676         ...
  1677        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1678      )
  1679 
  1680   and a theorem `split_t_case_asm' of the form
  1681 
  1682   P(t_case f1 ... fn x) =
  1683     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1684         ...
  1685        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1686      )
  1687   which can be added to a simpset via `addsplits'. The existing theorems
  1688   expand_list_case and expand_option_case have been renamed to
  1689   split_list_case and split_option_case.
  1690 
  1691 * HOL/Arithmetic:
  1692   - `pred n' is automatically converted to `n-1'.
  1693     Users are strongly encouraged not to use `pred' any longer,
  1694     because it will disappear altogether at some point.
  1695   - Users are strongly encouraged to write "0 < n" rather than
  1696     "n ~= 0". Theorems and proof tools have been modified towards this
  1697     `standard'.
  1698 
  1699 * HOL/Lists:
  1700   the function "set_of_list" has been renamed "set" (and its theorems too);
  1701   the function "nth" now takes its arguments in the reverse order and
  1702   has acquired the infix notation "!" as in "xs!n".
  1703 
  1704 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1705 
  1706 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1707   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1708 
  1709 * HOL/record: extensible records with schematic structural subtyping
  1710 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1711 still lacks various theorems and concrete record syntax;
  1712 
  1713 
  1714 *** HOLCF ***
  1715 
  1716 * removed "axioms" and "generated by" sections;
  1717 
  1718 * replaced "ops" section by extended "consts" section, which is capable of
  1719   handling the continuous function space "->" directly;
  1720 
  1721 * domain package:
  1722   . proves theorems immediately and stores them in the theory,
  1723   . creates hierachical name space,
  1724   . now uses normal mixfix annotations (instead of cinfix...),
  1725   . minor changes to some names and values (for consistency),
  1726   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1727   . separator between mutual domain defs: changed "," to "and",
  1728   . improved handling of sort constraints;  now they have to
  1729     appear on the left-hand side of the equations only;
  1730 
  1731 * fixed LAM <x,y,zs>.b syntax;
  1732 
  1733 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1734 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1735 
  1736 
  1737 *** FOL and ZF ***
  1738 
  1739 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1740   with `addloop' of the simplifier to faciliate case splitting in premises.
  1741 
  1742 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1743 in HOL, they strip ALL and --> from proved theorems;
  1744 
  1745 
  1746 
  1747 New in Isabelle94-8 (May 1997)
  1748 ------------------------------
  1749 
  1750 *** General Changes ***
  1751 
  1752 * new utilities to build / run / maintain Isabelle etc. (in parts
  1753 still somewhat experimental); old Makefiles etc. still functional;
  1754 
  1755 * new 'Isabelle System Manual';
  1756 
  1757 * INSTALL text, together with ./configure and ./build scripts;
  1758 
  1759 * reimplemented type inference for greater efficiency, better error
  1760 messages and clean internal interface;
  1761 
  1762 * prlim command for dealing with lots of subgoals (an easier way of
  1763 setting goals_limit);
  1764 
  1765 
  1766 *** Syntax ***
  1767 
  1768 * supports alternative (named) syntax tables (parser and pretty
  1769 printer); internal interface is provided by add_modesyntax(_i);
  1770 
  1771 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1772 be used in conjunction with the Isabelle symbol font; uses the
  1773 "symbols" syntax table;
  1774 
  1775 * added token_translation interface (may translate name tokens in
  1776 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1777 the current print_mode); IMPORTANT: user print translation functions
  1778 are responsible for marking newly introduced bounds
  1779 (Syntax.mark_boundT);
  1780 
  1781 * token translations for modes "xterm" and "xterm_color" that display
  1782 names in bold, underline etc. or colors (which requires a color
  1783 version of xterm);
  1784 
  1785 * infixes may now be declared with names independent of their syntax;
  1786 
  1787 * added typed_print_translation (like print_translation, but may
  1788 access type of constant);
  1789 
  1790 
  1791 *** Classical Reasoner ***
  1792 
  1793 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1794 some limitations.  Blast_tac...
  1795   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1796   + ignores elimination rules that don't have the correct format
  1797         (the conclusion MUST be a formula variable)
  1798   + ignores types, which can make HOL proofs fail
  1799   + rules must not require higher-order unification, e.g. apply_type in ZF
  1800     [message "Function Var's argument not a bound variable" relates to this]
  1801   + its proof strategy is more general but can actually be slower
  1802 
  1803 * substitution with equality assumptions no longer permutes other
  1804 assumptions;
  1805 
  1806 * minor changes in semantics of addafter (now called addaltern); renamed
  1807 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1808 (and access functions for it);
  1809 
  1810 * improved combination of classical reasoner and simplifier:
  1811   + functions for handling clasimpsets
  1812   + improvement of addss: now the simplifier is called _after_ the
  1813     safe steps.
  1814   + safe variant of addss called addSss: uses safe simplifications
  1815     _during_ the safe steps. It is more complete as it allows multiple
  1816     instantiations of unknowns (e.g. with slow_tac).
  1817 
  1818 *** Simplifier ***
  1819 
  1820 * added interface for simplification procedures (functions that
  1821 produce *proven* rewrite rules on the fly, depending on current
  1822 redex);
  1823 
  1824 * ordering on terms as parameter (used for ordered rewriting);
  1825 
  1826 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1827 
  1828 * the solver is now split into a safe and an unsafe part.
  1829 This should be invisible for the normal user, except that the
  1830 functions setsolver and addsolver have been renamed to setSolver and
  1831 addSolver; added safe_asm_full_simp_tac;
  1832 
  1833 
  1834 *** HOL ***
  1835 
  1836 * a generic induction tactic `induct_tac' which works for all datatypes and
  1837 also for type `nat';
  1838 
  1839 * a generic case distinction tactic `exhaust_tac' which works for all
  1840 datatypes and also for type `nat';
  1841 
  1842 * each datatype comes with a function `size';
  1843 
  1844 * patterns in case expressions allow tuple patterns as arguments to
  1845 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1846 
  1847 * primrec now also works with type nat;
  1848 
  1849 * recdef: a new declaration form, allows general recursive functions to be
  1850 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1851 
  1852 * the constant for negation has been renamed from "not" to "Not" to
  1853 harmonize with FOL, ZF, LK, etc.;
  1854 
  1855 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1856 infinite lists;
  1857 
  1858 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1859 
  1860 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1861 problems in commutative rings, using axiomatic type classes for + and *;
  1862 
  1863 * more examples in HOL/MiniML and HOL/Auth;
  1864 
  1865 * more default rewrite rules for quantifiers, union/intersection;
  1866 
  1867 * a new constant `arbitrary == @x.False';
  1868 
  1869 * HOLCF/IOA replaces old HOL/IOA;
  1870 
  1871 * HOLCF changes: derived all rules and arities
  1872   + axiomatic type classes instead of classes
  1873   + typedef instead of faking type definitions
  1874   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1875   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1876   + eliminated the types void, one, tr
  1877   + use unit lift and bool lift (with translations) instead of one and tr
  1878   + eliminated blift from Lift3.thy (use Def instead of blift)
  1879   all eliminated rules are derived as theorems --> no visible changes ;
  1880 
  1881 
  1882 *** ZF ***
  1883 
  1884 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1885 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1886 as ZF_cs addSIs [equalityI];
  1887 
  1888 
  1889 
  1890 New in Isabelle94-7 (November 96)
  1891 ---------------------------------
  1892 
  1893 * allowing negative levels (as offsets) in prlev and choplev;
  1894 
  1895 * super-linear speedup for large simplifications;
  1896 
  1897 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1898 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1899 FAIL); can suppress it using the command Delsimps (ex_simps @
  1900 all_simps); De Morgan laws are also now included, by default;
  1901 
  1902 * improved printing of ==>  :  ~:
  1903 
  1904 * new object-logic "Sequents" adds linear logic, while replacing LK
  1905 and Modal (thanks to Sara Kalvala);
  1906 
  1907 * HOL/Auth: correctness proofs for authentication protocols;
  1908 
  1909 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1910 examples on HOL/Auth);
  1911 
  1912 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1913 the rewriter and classical reasoner simultaneously;
  1914 
  1915 * function uresult no longer returns theorems in "standard" format;
  1916 regain previous version by: val uresult = standard o uresult;
  1917 
  1918 
  1919 
  1920 New in Isabelle94-6
  1921 -------------------
  1922 
  1923 * oracles -- these establish an interface between Isabelle and trusted
  1924 external reasoners, which may deliver results as theorems;
  1925 
  1926 * proof objects (in particular record all uses of oracles);
  1927 
  1928 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1929 
  1930 * "constdefs" section in theory files;
  1931 
  1932 * "primrec" section (HOL) no longer requires names;
  1933 
  1934 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1935 
  1936 
  1937 
  1938 New in Isabelle94-5
  1939 -------------------
  1940 
  1941 * reduced space requirements;
  1942 
  1943 * automatic HTML generation from theories;
  1944 
  1945 * theory files no longer require "..." (quotes) around most types;
  1946 
  1947 * new examples, including two proofs of the Church-Rosser theorem;
  1948 
  1949 * non-curried (1994) version of HOL is no longer distributed;
  1950 
  1951 
  1952 
  1953 New in Isabelle94-4
  1954 -------------------
  1955 
  1956 * greatly reduced space requirements;
  1957 
  1958 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1959 
  1960 * searchable theorem database (see the section "Retrieving theorems" on
  1961 page 8 of the Reference Manual);
  1962 
  1963 * new examples, including Grabczewski's monumental case study of the
  1964 Axiom of Choice;
  1965 
  1966 * The previous version of HOL renamed to Old_HOL;
  1967 
  1968 * The new version of HOL (previously called CHOL) uses a curried syntax
  1969 for functions.  Application looks like f a b instead of f(a,b);
  1970 
  1971 * Mutually recursive inductive definitions finally work in HOL;
  1972 
  1973 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1974 translates to the operator "split";
  1975 
  1976 
  1977 
  1978 New in Isabelle94-3
  1979 -------------------
  1980 
  1981 * new infix operator, addss, allowing the classical reasoner to
  1982 perform simplification at each step of its search.  Example:
  1983         fast_tac (cs addss ss)
  1984 
  1985 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1986 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1987 look like (a,b) instead of <a,b>;
  1988 
  1989 * PLEASE NOTE: CHOL will eventually replace HOL!
  1990 
  1991 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1992 It translates to the operator "split".  A new theory of integers is available;
  1993 
  1994 * In ZF, integer numerals now denote two's-complement binary integers.
  1995 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1996 
  1997 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1998 of the Axiom of Choice;
  1999 
  2000 
  2001 
  2002 New in Isabelle94-2
  2003 -------------------
  2004 
  2005 * Significantly faster resolution;
  2006 
  2007 * the different sections in a .thy file can now be mixed and repeated
  2008 freely;
  2009 
  2010 * Database of theorems for FOL, HOL and ZF.  New
  2011 commands including qed, qed_goal and bind_thm store theorems in the database.
  2012 
  2013 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2014 a given theory (thms_of), or find out what theory a theorem was proved in
  2015 (theory_of_thm);
  2016 
  2017 * Bugs fixed in the inductive definition and datatype packages;
  2018 
  2019 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2020 and HOL_dup_cs obsolete;
  2021 
  2022 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2023 have been removed;
  2024 
  2025 * Simpler definition of function space in ZF;
  2026 
  2027 * new results about cardinal and ordinal arithmetic in ZF;
  2028 
  2029 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2030 types;
  2031 
  2032 
  2033 $Id$