NEWS
author wenzelm
Mon Oct 08 14:30:28 2001 +0200 (2001-10-08)
changeset 11712 deb8cac87063
parent 11702 ebfe5ba905b0
child 11722 78cf55fd57c6
permissions -rw-r--r--
* added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
note that these symbols are unavailable in Proof General / X-Symbol;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2001 (?? 2001)
     6 -----------------------------
     7 
     8 *** Document preparation ***
     9 
    10 * support bold style (for single symbols only), input syntax is like
    11 this: "\<^bold>\<alpha>" or "\<^bold>A";
    12 
    13 * \<bullet> is no output as bold \cdot by default, which looks much
    14 better in printed text;
    15 
    16 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    17 note that these symbols are currently unavailable in Proof General /
    18 X-Symbol;
    19 
    20 
    21 *** Isar ***
    22 
    23 * renamed "antecedent" case to "rule_context";
    24 
    25 * improved proof by cases and induction:
    26   - moved induct/cases attributes to Pure;
    27   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    28   - generic setup instantiated for FOL and HOL;
    29   - removed obsolete "(simplified)" and "(stripped)" options;
    30 
    31 * HOL: 'recdef' now fails on unfinished automated proofs, use
    32 "(permissive)" option to recover old behavior;
    33 
    34 * HOL: 'inductive' now longer features separate (collective)
    35 attributes for 'intros';
    36 
    37 
    38 *** HOL ***
    39 
    40 * HOL: moved over to sane numeral syntax; the new policy is as
    41 follows:
    42 
    43   - 0 and 1 are polymorphic constants, which are defined on any
    44   numeric type (nat, int, real etc.);
    45 
    46   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
    47   binary representation internally;
    48 
    49   - type nat has special constructor Suc, and generally prefers Suc 0
    50   over 1::nat and Suc (Suc 0) over 2::nat;
    51 
    52 This change may cause significant INCOMPATIBILITIES; here are some
    53 hints on converting existing sources:
    54 
    55   - due to the new "num" token, "-0" and "-1" etc. are now atomic
    56   entities, so expressions involving "-" (unary or binary minus) need
    57   to be spaced properly;
    58 
    59   - existing occurrences of "1" may need to be constraint "1::nat" or
    60   even replaced by Suc 0; similar for old "2";
    61 
    62   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
    63 
    64   - remove all special provisions on numerals in proofs;
    65 
    66 * HOL: linorder_less_split superseded by linorder_cases;
    67 
    68 * HOL: added "The" definite description operator; move Hilbert's "Eps"
    69 to peripheral theory "Hilbert_Choice";
    70 
    71 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
    72 in this (rare) case use:
    73 
    74   delSWrapper "split_all_tac"
    75   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
    76 
    77 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
    78 MAY FAIL;
    79 
    80 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
    81 Isabelle's type classes, ^ on functions and relations has too general
    82 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
    83 necessary to attach explicit type constraints;
    84 
    85 * HOL: syntax translations now work properly with numerals and records
    86 expressions;
    87 
    88 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
    89 Florian Kammüller;
    90 
    91 * HOL: eliminated global items
    92 
    93   const "()" -> "Product_Type.Unity"
    94   type "unit" -> "Product_Type.unit"
    95 
    96 
    97 *** ZF ***
    98 
    99 * ZF: the integer library now covers quotients and remainders, with
   100 many laws relating division to addition, multiplication, etc.;
   101 
   102 
   103 *** General ***
   104 
   105 * Meta-level proof terms (by Stefan Berghofer), see also ref manual;
   106 
   107 * new token syntax "num" for plain numerals (without "#" of "xnum");
   108 potential INCOMPATIBILITY, since -0, -1 etc. are now separate tokens,
   109 so expressions involving minus need to be spaced properly;
   110 
   111 * Classical reasoner: renamed addaltern to addafter, addSaltern to
   112 addSafter;
   113 
   114 * syntax: support non-oriented infixes;
   115 
   116 * print modes "type_brackets" and "no_type_brackets" control output of
   117 nested => (types); the default behavior is "brackets";
   118 
   119 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   120 
   121 * system: Proof General keywords specification is now part of the
   122 Isabelle distribution (see etc/isar-keywords.el);
   123 
   124 * system: smart selection of Isabelle process versus Isabelle
   125 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   126 run both "isabelle" and "Isabelle" even if file names are badly
   127 damaged (executable inspects the case of the first letter of its own
   128 name); added separate "isabelle-process" and "isabelle-interface";
   129 
   130 
   131 
   132 New in Isabelle99-2 (February 2001)
   133 -----------------------------------
   134 
   135 *** Overview of INCOMPATIBILITIES ***
   136 
   137 * HOL: please note that theories in the Library and elsewhere often use the
   138 new-style (Isar) format; to refer to their theorems in an ML script you must
   139 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   140 
   141 * HOL: inductive package no longer splits induction rule aggressively,
   142 but only as far as specified by the introductions given; the old
   143 format may be recovered via ML function complete_split_rule or attribute
   144 'split_rule (complete)';
   145 
   146 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   147 gfp_Tarski to gfp_unfold;
   148 
   149 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   150 
   151 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   152 relation); infix "^^" has been renamed "``"; infix "``" has been
   153 renamed "`"; "univalent" has been renamed "single_valued";
   154 
   155 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   156 operation;
   157 
   158 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   159 
   160 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   161 
   162 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   163 consequence, it is no longer monotonic wrt. the local goal context
   164 (which is now passed through the inductive cases);
   165 
   166 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   167 \<gg> to \<ggreater>;
   168 
   169 
   170 *** Document preparation ***
   171 
   172 * \isabellestyle{NAME} selects version of Isabelle output (currently
   173 available: are "it" for near math-mode best-style output, "sl" for
   174 slanted text style, and "tt" for plain type-writer; if no
   175 \isabellestyle command is given, output is according to slanted
   176 type-writer);
   177 
   178 * support sub/super scripts (for single symbols only), input syntax is
   179 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   180 
   181 * some more standard symbols; see Appendix A of the system manual for
   182 the complete list of symbols defined in isabellesym.sty;
   183 
   184 * improved isabelle style files; more abstract symbol implementation
   185 (should now use \isamath{...} and \isatext{...} in custom symbol
   186 definitions);
   187 
   188 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   189 state; Note that presentation of goal states does not conform to
   190 actual human-readable proof documents.  Please do not include goal
   191 states into document output unless you really know what you are doing!
   192 
   193 * proper indentation of antiquoted output with proportional LaTeX
   194 fonts;
   195 
   196 * no_document ML operator temporarily disables LaTeX document
   197 generation;
   198 
   199 * isatool unsymbolize tunes sources for plain ASCII communication;
   200 
   201 
   202 *** Isar ***
   203 
   204 * Pure: Isar now suffers initial goal statements to contain unbound
   205 schematic variables (this does not conform to actual readable proof
   206 documents, due to unpredictable outcome and non-compositional proof
   207 checking); users who know what they are doing may use schematic goals
   208 for Prolog-style synthesis of proven results;
   209 
   210 * Pure: assumption method (an implicit finishing) now handles actual
   211 rules as well;
   212 
   213 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   214 initial goal, declare "that" only as Pure intro (only for single
   215 steps); the "that" rule assumption may now be involved in implicit
   216 finishing, thus ".." becomes a feasible for trivial obtains;
   217 
   218 * Pure: default proof step now includes 'intro_classes'; thus trivial
   219 instance proofs may be performed by "..";
   220 
   221 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   222 statements as well;
   223 
   224 * Pure: more robust selection of calculational rules;
   225 
   226 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   227 rule (as well as the assumption rule);
   228 
   229 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   230 lemmas, using the graph browser tool;
   231 
   232 * Pure: predict failure of "show" in interactive mode;
   233 
   234 * Pure: 'thms_containing' now takes actual terms as arguments;
   235 
   236 * HOL: improved method 'induct' --- now handles non-atomic goals
   237 (potential INCOMPATIBILITY); tuned error handling;
   238 
   239 * HOL: cases and induct rules now provide explicit hints about the
   240 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   241 any remaining facts are inserted into the goal verbatim;
   242 
   243 * HOL: local contexts (aka cases) may now contain term bindings as
   244 well; the 'cases' and 'induct' methods new provide a ?case binding for
   245 the result to be shown in each case;
   246 
   247 * HOL: added 'recdef_tc' command;
   248 
   249 * isatool convert assists in eliminating legacy ML scripts;
   250 
   251 
   252 *** HOL ***
   253 
   254 * HOL/Library: a collection of generic theories to be used together
   255 with main HOL; the theory loader path already includes this directory
   256 by default; the following existing theories have been moved here:
   257 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   258 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   259 
   260 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   261 modelling and verification task performed in Isabelle/HOL +
   262 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   263 
   264 * HOL/Algebra: special summation operator SUM no longer exists, it has
   265 been replaced by setsum; infix 'assoc' now has priority 50 (like
   266 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   267 'domain', this makes the theory consistent with mathematical
   268 literature;
   269 
   270 * HOL basics: added overloaded operations "inverse" and "divide"
   271 (infix "/"), syntax for generic "abs" operation, generic summation
   272 operator \<Sum>;
   273 
   274 * HOL/typedef: simplified package, provide more useful rules (see also
   275 HOL/subset.thy);
   276 
   277 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   278 now expressed as a proper nested rule (old-style tactic scripts may
   279 require atomize_strip_tac to cope with non-atomic premises);
   280 
   281 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   282 to "split_conv" (old name still available for compatibility);
   283 
   284 * HOL: improved concrete syntax for strings (e.g. allows translation
   285 rules with string literals);
   286 
   287 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   288 and Fleuriot's mechanization of analysis;
   289 
   290 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   291 
   292 
   293 *** CTT ***
   294 
   295 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   296 "lam" is displayed as TWO lambda-symbols
   297 
   298 * CTT: theory Main now available, containing everything (that is, Bool
   299 and Arith);
   300 
   301 
   302 *** General ***
   303 
   304 * Pure: the Simplifier has been implemented properly as a derived rule
   305 outside of the actual kernel (at last!); the overall performance
   306 penalty in practical applications is about 50%, while reliability of
   307 the Isabelle inference kernel has been greatly improved;
   308 
   309 * print modes "brackets" and "no_brackets" control output of nested =>
   310 (types) and ==> (props); the default behaviour is "brackets";
   311 
   312 * Provers: fast_tac (and friends) now handle actual object-logic rules
   313 as assumptions as well;
   314 
   315 * system: support Poly/ML 4.0;
   316 
   317 * system: isatool install handles KDE version 1 or 2;
   318 
   319 
   320 
   321 New in Isabelle99-1 (October 2000)
   322 ----------------------------------
   323 
   324 *** Overview of INCOMPATIBILITIES ***
   325 
   326 * HOL: simplification of natural numbers is much changed; to partly
   327 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   328 issue the following ML commands:
   329 
   330   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   331   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   332 
   333 * HOL: simplification no longer dives into case-expressions; this is
   334 controlled by "t.weak_case_cong" for each datatype t;
   335 
   336 * HOL: nat_less_induct renamed to less_induct;
   337 
   338 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   339 fixsome to patch .thy and .ML sources automatically;
   340 
   341   select_equality  -> some_equality
   342   select_eq_Ex     -> some_eq_ex
   343   selectI2EX       -> someI2_ex
   344   selectI2         -> someI2
   345   selectI          -> someI
   346   select1_equality -> some1_equality
   347   Eps_sym_eq       -> some_sym_eq_trivial
   348   Eps_eq           -> some_eq_trivial
   349 
   350 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   351 
   352 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   353 instead);
   354 
   355 * HOL: the recursion equations generated by 'recdef' are now called
   356 f.simps instead of f.rules;
   357 
   358 * HOL: qed_spec_mp now also handles bounded ALL as well;
   359 
   360 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   361 sometimes be needed;
   362 
   363 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   364 
   365 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   366 
   367 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   368 product is now "<*>" instead of "Times"; the lexicographic product is
   369 now "<*lex*>" instead of "**";
   370 
   371 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   372 of main HOL, but was unused); better use HOL's datatype package;
   373 
   374 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   375 the old syntax may be recovered as follows:
   376 
   377   syntax (symbols)
   378     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   379       (infixl "\\<oplus>" 100)
   380 
   381 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   382 
   383 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   384 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   385 internally;
   386 
   387 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   388 changed from A/r to A//r;
   389 
   390 * ZF: new treatment of arithmetic (nat & int) may break some old
   391 proofs;
   392 
   393 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   394 rulify -> rule_format, elimify -> elim_format, ...);
   395 
   396 * Isar/Provers: intro/elim/dest attributes changed; renamed
   397 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   398 should have to change intro!! to intro? only); replaced "delrule" by
   399 "rule del";
   400 
   401 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   402 
   403 * Provers: strengthened force_tac by using new first_best_tac;
   404 
   405 * LaTeX document preparation: several changes of isabelle.sty (see
   406 lib/texinputs);
   407 
   408 
   409 *** Document preparation ***
   410 
   411 * formal comments (text blocks etc.) in new-style theories may now
   412 contain antiquotations of thm/prop/term/typ/text to be presented
   413 according to latex print mode; concrete syntax is like this:
   414 @{term[show_types] "f(x) = a + x"};
   415 
   416 * isatool mkdir provides easy setup of Isabelle session directories,
   417 including proper document sources;
   418 
   419 * generated LaTeX sources are now deleted after successful run
   420 (isatool document -c); may retain a copy somewhere else via -D option
   421 of isatool usedir;
   422 
   423 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   424 style files, achieving self-contained LaTeX sources and simplifying
   425 LaTeX debugging;
   426 
   427 * old-style theories now produce (crude) LaTeX output as well;
   428 
   429 * browser info session directories are now self-contained (may be put
   430 on WWW server seperately); improved graphs of nested sessions; removed
   431 graph for 'all sessions';
   432 
   433 * several improvements in isabelle style files; \isabellestyle{it}
   434 produces fake math mode output; \isamarkupheader is now \section by
   435 default; see lib/texinputs/isabelle.sty etc.;
   436 
   437 
   438 *** Isar ***
   439 
   440 * Isar/Pure: local results and corresponding term bindings are now
   441 subject to Hindley-Milner polymorphism (similar to ML); this
   442 accommodates incremental type-inference very nicely;
   443 
   444 * Isar/Pure: new derived language element 'obtain' supports
   445 generalized existence reasoning;
   446 
   447 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   448 support accumulation of results, without applying any rules yet;
   449 useful to collect intermediate results without explicit name
   450 references, and for use with transitivity rules with more than 2
   451 premises;
   452 
   453 * Isar/Pure: scalable support for case-analysis type proofs: new
   454 'case' language element refers to local contexts symbolically, as
   455 produced by certain proof methods; internally, case names are attached
   456 to theorems as "tags";
   457 
   458 * Isar/Pure: theory command 'hide' removes declarations from
   459 class/type/const name spaces;
   460 
   461 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   462 indicate potential overloading;
   463 
   464 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   465 
   466 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   467 "{a,b,c}" instead of {a,b,c};
   468 
   469 * Isar/Pure now provides its own version of intro/elim/dest
   470 attributes; useful for building new logics, but beware of confusion
   471 with the version in Provers/classical;
   472 
   473 * Isar/Pure: the local context of (non-atomic) goals is provided via
   474 case name 'antecedent';
   475 
   476 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   477 to the current context is now done automatically);
   478 
   479 * Isar/Pure: theory command 'method_setup' provides a simple interface
   480 for definining proof methods in ML;
   481 
   482 * Isar/Provers: intro/elim/dest attributes changed; renamed
   483 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   484 most cases, one should have to change intro!! to intro? only);
   485 replaced "delrule" by "rule del";
   486 
   487 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   488 'symmetric' attribute (the latter supercedes [RS sym]);
   489 
   490 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   491 method modifier); 'simp' method: 'only:' modifier removes loopers as
   492 well (including splits);
   493 
   494 * Isar/Provers: Simplifier and Classical methods now support all kind
   495 of modifiers used in the past, including 'cong', 'iff', etc.
   496 
   497 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   498 of Simplifier and Classical reasoner);
   499 
   500 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   501 now support named cases; major packages (inductive, datatype, primrec,
   502 recdef) support case names and properly name parameters;
   503 
   504 * Isar/HOL: new transitivity rules for substitution in inequalities --
   505 monotonicity conditions are extracted to be proven at end of
   506 calculations;
   507 
   508 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   509 method anyway;
   510 
   511 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   512 split_if split_if_asm; datatype package provides theorems foo.splits =
   513 foo.split foo.split_asm for each datatype;
   514 
   515 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   516 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   517 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   518 use "(cases (simplified))" method in proper proof texts);
   519 
   520 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   521 
   522 * Isar: names of theorems etc. may be natural numbers as well;
   523 
   524 * Isar: 'pr' command: optional arguments for goals_limit and
   525 ProofContext.prems_limit; no longer prints theory contexts, but only
   526 proof states;
   527 
   528 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   529 additional print modes to be specified; e.g. "pr(latex)" will print
   530 proof state according to the Isabelle LaTeX style;
   531 
   532 * Isar: improved support for emulating tactic scripts, including proof
   533 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   534 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   535 (for HOL datatypes);
   536 
   537 * Isar: simplified (more robust) goal selection of proof methods: 1st
   538 goal, all goals, or explicit goal specifier (tactic emulation); thus
   539 'proof method scripts' have to be in depth-first order;
   540 
   541 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   542 
   543 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   544 should instead use individual commands for printing items
   545 (print_commands, print_methods etc.);
   546 
   547 * Isar: added 'nothing' --- the empty list of theorems;
   548 
   549 
   550 *** HOL ***
   551 
   552 * HOL/MicroJava: formalization of a fragment of Java, together with a
   553 corresponding virtual machine and a specification of its bytecode
   554 verifier and a lightweight bytecode verifier, including proofs of
   555 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   556 Cornelia Pusch (see also the homepage of project Bali at
   557 http://isabelle.in.tum.de/Bali/);
   558 
   559 * HOL/Algebra: new theory of rings and univariate polynomials, by
   560 Clemens Ballarin;
   561 
   562 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   563 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   564 Rasmussen;
   565 
   566 * HOL/Lattice: fundamental concepts of lattice theory and order
   567 structures, including duals, properties of bounds versus algebraic
   568 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   569 Theorem for complete lattices etc.; may also serve as a demonstration
   570 for abstract algebraic reasoning using axiomatic type classes, and
   571 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   572 
   573 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   574 von Oheimb;
   575 
   576 * HOL/IMPP: extension of IMP with local variables and mutually
   577 recursive procedures, by David von Oheimb;
   578 
   579 * HOL/Lambda: converted into new-style theory and document;
   580 
   581 * HOL/ex/Multiquote: example of multiple nested quotations and
   582 anti-quotations -- basically a generalized version of de-Bruijn
   583 representation; very useful in avoiding lifting of operations;
   584 
   585 * HOL/record: added general record equality rule to simpset; fixed
   586 select-update simplification procedure to handle extended records as
   587 well; admit "r" as field name;
   588 
   589 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   590 other numeric types and also as the identity of groups, rings, etc.;
   591 
   592 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   593 Types nat and int belong to this axclass;
   594 
   595 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   596    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   597    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   598   two terms #m*u and #n*u are replaced by #(m+n)*u
   599     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   600   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   601     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   602 
   603 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   604 powerful prover for predicate logic but knows nothing of clasets; see
   605 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   606 
   607 * HOL: new version of "case_tac" subsumes both boolean case split and
   608 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   609 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   610 
   611 * HOL: simplification no longer dives into case-expressions: only the
   612 selector expression is simplified, but not the remaining arms; to
   613 enable full simplification of case-expressions for datatype t, you may
   614 remove t.weak_case_cong from the simpset, either globally (Delcongs
   615 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   616 
   617 * HOL/recdef: the recursion equations generated by 'recdef' for
   618 function 'f' are now called f.simps instead of f.rules; if all
   619 termination conditions are proved automatically, these simplification
   620 rules are added to the simpset, as in primrec; rules may be named
   621 individually as well, resulting in a separate list of theorems for
   622 each equation;
   623 
   624 * HOL/While is a new theory that provides a while-combinator. It
   625 permits the definition of tail-recursive functions without the
   626 provision of a termination measure. The latter is necessary once the
   627 invariant proof rule for while is applied.
   628 
   629 * HOL: new (overloaded) notation for the set of elements below/above
   630 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   631 
   632 * HOL: theorems impI, allI, ballI bound as "strip";
   633 
   634 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   635 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   636 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   637 
   638 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   639 
   640 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   641 main HOL, but was unused);
   642 
   643 * HOL: fewer consts declared as global (e.g. have to refer to
   644 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   645 
   646 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   647 in case of overlap with user translations (e.g. judgements over
   648 tuples); (note that the underlying logical represenation is still
   649 bogus);
   650 
   651 
   652 *** ZF ***
   653 
   654 * ZF: simplification automatically cancels common terms in arithmetic
   655 expressions over nat and int;
   656 
   657 * ZF: new treatment of nat to minimize type-checking: all operators
   658 coerce their operands to a natural number using the function natify,
   659 making the algebraic laws unconditional;
   660 
   661 * ZF: as above, for int: operators coerce their operands to an integer
   662 using the function intify;
   663 
   664 * ZF: the integer library now contains many of the usual laws for the
   665 orderings, including $<=, and monotonicity laws for $+ and $*;
   666 
   667 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   668 simplification;
   669 
   670 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   671 to the simplifier and classical reasoner simultaneously;
   672 
   673 
   674 *** General ***
   675 
   676 * Provers: blast_tac now handles actual object-logic rules as
   677 assumptions; note that auto_tac uses blast_tac internally as well;
   678 
   679 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   680 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   681 
   682 * Provers: delrules now handles destruct rules as well (no longer need
   683 explicit make_elim);
   684 
   685 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   686   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   687 use instead the strong form,
   688   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   689 in HOL, FOL and ZF the function cla_make_elim will create such rules
   690 from destruct-rules;
   691 
   692 * Provers: Simplifier.easy_setup provides a fast path to basic
   693 Simplifier setup for new object-logics;
   694 
   695 * Pure: AST translation rules no longer require constant head on LHS;
   696 
   697 * Pure: improved name spaces: ambiguous output is qualified; support
   698 for hiding of names;
   699 
   700 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   701 XSYMBOL_HOME; no longer need to do manual configuration in most
   702 situations;
   703 
   704 * system: compression of ML heaps images may now be controlled via -c
   705 option of isabelle and isatool usedir (currently only observed by
   706 Poly/ML);
   707 
   708 * system: isatool installfonts may handle X-Symbol fonts as well (very
   709 useful for remote X11);
   710 
   711 * system: provide TAGS file for Isabelle sources;
   712 
   713 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   714 order;
   715 
   716 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   717 timing flag supersedes proof_timing and Toplevel.trace;
   718 
   719 * ML: new combinators |>> and |>>> for incremental transformations
   720 with secondary results (e.g. certain theory extensions):
   721 
   722 * ML: PureThy.add_defs gets additional argument to indicate potential
   723 overloading (usually false);
   724 
   725 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   726 results;
   727 
   728 
   729 
   730 New in Isabelle99 (October 1999)
   731 --------------------------------
   732 
   733 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   734 
   735 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   736 are no longer simplified.  (This allows the simplifier to unfold recursive
   737 functional programs.)  To restore the old behaviour, declare
   738 
   739     Delcongs [if_weak_cong];
   740 
   741 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   742 complement;
   743 
   744 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   745 
   746 * HOL/datatype: mutual_induct_tac no longer exists --
   747   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   748 
   749 * HOL/typedef: fixed type inference for representing set; type
   750 arguments now have to occur explicitly on the rhs as type constraints;
   751 
   752 * ZF: The con_defs part of an inductive definition may no longer refer
   753 to constants declared in the same theory;
   754 
   755 * HOL, ZF: the function mk_cases, generated by the inductive
   756 definition package, has lost an argument.  To simplify its result, it
   757 uses the default simpset instead of a supplied list of theorems.
   758 
   759 * HOL/List: the constructors of type list are now Nil and Cons;
   760 
   761 * Simplifier: the type of the infix ML functions
   762         setSSolver addSSolver setSolver addSolver
   763 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   764 for packaging solvers. A solver is created via
   765         mk_solver: string -> (thm list -> int -> tactic) -> solver
   766 where the string argument is only a comment.
   767 
   768 
   769 *** Proof tools ***
   770 
   771 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   772 decision procedure for linear arithmetic. Currently it is used for
   773 types `nat', `int', and `real' in HOL (see below); it can, should and
   774 will be instantiated for other types and logics as well.
   775 
   776 * The simplifier now accepts rewrite rules with flexible heads, eg
   777      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   778   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   779   matching.
   780 
   781 
   782 *** General ***
   783 
   784 * New Isabelle/Isar subsystem provides an alternative to traditional
   785 tactical theorem proving; together with the ProofGeneral/isar user
   786 interface it offers an interactive environment for developing human
   787 readable proof documents (Isar == Intelligible semi-automated
   788 reasoning); for further information see isatool doc isar-ref,
   789 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   790 
   791 * improved and simplified presentation of theories: better HTML markup
   792 (including colors), graph views in several sizes; isatool usedir now
   793 provides a proper interface for user theories (via -P option); actual
   794 document preparation based on (PDF)LaTeX is available as well (for
   795 new-style theories only); see isatool doc system for more information;
   796 
   797 * native support for Proof General, both for classic Isabelle and
   798 Isabelle/Isar;
   799 
   800 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   801 using the graph browser tool;
   802 
   803 * Isabelle manuals now also available as PDF;
   804 
   805 * theory loader rewritten from scratch (may not be fully
   806 bug-compatible); old loadpath variable has been replaced by show_path,
   807 add_path, del_path, reset_path functions; new operations such as
   808 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   809 isatool doc ref);
   810 
   811 * improved isatool install: option -k creates KDE application icon,
   812 option -p DIR installs standalone binaries;
   813 
   814 * added ML_PLATFORM setting (useful for cross-platform installations);
   815 more robust handling of platform specific ML images for SML/NJ;
   816 
   817 * the settings environment is now statically scoped, i.e. it is never
   818 created again in sub-processes invoked from isabelle, isatool, or
   819 Isabelle;
   820 
   821 * path element specification '~~' refers to '$ISABELLE_HOME';
   822 
   823 * in locales, the "assumes" and "defines" parts may be omitted if
   824 empty;
   825 
   826 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   827 long arrows);
   828 
   829 * new print_mode "HTML";
   830 
   831 * new flag show_tags controls display of tags of theorems (which are
   832 basically just comments that may be attached by some tools);
   833 
   834 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   835 mode and goal output format:
   836 
   837 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   838 244c244
   839 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   840 ---
   841 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   842 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   843 181c181
   844 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   845 ---
   846 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   847 
   848 * function bind_thms stores lists of theorems (cf. bind_thm);
   849 
   850 * new shorthand tactics ftac, eatac, datac, fatac;
   851 
   852 * qed (and friends) now accept "" as result name; in that case the
   853 theorem is not stored, but proper checks and presentation of the
   854 result still apply;
   855 
   856 * theorem database now also indexes constants "Trueprop", "all",
   857 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   858 
   859 
   860 *** HOL ***
   861 
   862 ** HOL arithmetic **
   863 
   864 * There are now decision procedures for linear arithmetic over nat and
   865 int:
   866 
   867 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   868 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   869 are treated as atomic; subformulae not involving type `nat' or `int'
   870 are ignored; quantified subformulae are ignored unless they are
   871 positive universal or negative existential. The tactic has to be
   872 invoked by hand and can be a little bit slow. In particular, the
   873 running time is exponential in the number of occurrences of `min' and
   874 `max', and `-' on `nat'.
   875 
   876 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   877 (negated) (in)equalities among the premises and the conclusion into
   878 account (i.e. no compound formulae) and does not know about `min' and
   879 `max', and `-' on `nat'. It is fast and is used automatically by the
   880 simplifier.
   881 
   882 NB: At the moment, these decision procedures do not cope with mixed
   883 nat/int formulae where the two parts interact, such as `m < n ==>
   884 int(m) < int(n)'.
   885 
   886 * HOL/Numeral provides a generic theory of numerals (encoded
   887 efficiently as bit strings); setup for types nat/int/real is in place;
   888 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   889 int, existing theories and proof scripts may require a few additional
   890 type constraints;
   891 
   892 * integer division and remainder can now be performed on constant
   893 arguments;
   894 
   895 * many properties of integer multiplication, division and remainder
   896 are now available;
   897 
   898 * An interface to the Stanford Validity Checker (SVC) is available through the
   899 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   900 are proved automatically.  SVC must be installed separately, and its results
   901 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   902 invocation of the underlying oracle).  For SVC see
   903   http://verify.stanford.edu/SVC
   904 
   905 * IsaMakefile: the HOL-Real target now builds an actual image;
   906 
   907 
   908 ** HOL misc **
   909 
   910 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   911 (in Isabelle/Isar) -- by Gertrud Bauer;
   912 
   913 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   914 analysis for assembly languages with subtypes;
   915 
   916 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   917 -- avoids syntactic ambiguities and treats state, transition, and
   918 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   919 changed syntax and (many) tactics;
   920 
   921 * HOL/inductive: Now also handles more general introduction rules such
   922   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   923   theorems are now maintained within the theory (maintained via the
   924   "mono" attribute);
   925 
   926 * HOL/datatype: Now also handles arbitrarily branching datatypes
   927   (using function types) such as
   928 
   929   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   930 
   931 * HOL/record: record_simproc (part of the default simpset) takes care
   932 of selectors applied to updated records; record_split_tac is no longer
   933 part of the default claset; update_defs may now be removed from the
   934 simpset in many cases; COMPATIBILITY: old behavior achieved by
   935 
   936   claset_ref () := claset() addSWrapper record_split_wrapper;
   937   Delsimprocs [record_simproc]
   938 
   939 * HOL/typedef: fixed type inference for representing set; type
   940 arguments now have to occur explicitly on the rhs as type constraints;
   941 
   942 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   943 names rather than an ML expression;
   944 
   945 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   946 supplied later.  Program schemes can be defined, such as
   947     "While B C s = (if B s then While B C (C s) else s)"
   948 where the well-founded relation can be chosen after B and C have been given.
   949 
   950 * HOL/List: the constructors of type list are now Nil and Cons;
   951 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   952 course, ML tools referring to List.list.op # etc. have to be adapted;
   953 
   954 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   955 disabled by default; run isabelle with option -m HOL to get back to
   956 the original Gordon/HOL-style output;
   957 
   958 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   959 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   960 
   961 * HOL basic syntax simplified (more orthogonal): all variants of
   962 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   963 Eps operator is provided as well: "SOME x. P[x]";
   964 
   965 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   966 
   967 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   968 thus available for user theories;
   969 
   970 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   971 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   972 time;
   973 
   974 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   975 several times and then mp;
   976 
   977 
   978 *** LK ***
   979 
   980 * the notation <<...>> is now available as a notation for sequences of
   981 formulas;
   982 
   983 * the simplifier is now installed
   984 
   985 * the axiom system has been generalized (thanks to Soren Heilmann)
   986 
   987 * the classical reasoner now has a default rule database
   988 
   989 
   990 *** ZF ***
   991 
   992 * new primrec section allows primitive recursive functions to be given
   993 directly (as in HOL) over datatypes and the natural numbers;
   994 
   995 * new tactics induct_tac and exhaust_tac for induction (or case
   996 analysis) over datatypes and the natural numbers;
   997 
   998 * the datatype declaration of type T now defines the recursor T_rec;
   999 
  1000 * simplification automatically does freeness reasoning for datatype
  1001 constructors;
  1002 
  1003 * automatic type-inference, with AddTCs command to insert new
  1004 type-checking rules;
  1005 
  1006 * datatype introduction rules are now added as Safe Introduction rules
  1007 to the claset;
  1008 
  1009 * the syntax "if P then x else y" is now available in addition to
  1010 if(P,x,y);
  1011 
  1012 
  1013 *** Internal programming interfaces ***
  1014 
  1015 * tuned simplifier trace output; new flag debug_simp;
  1016 
  1017 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1018 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1019 
  1020 * AxClass.axclass_tac lost the theory argument;
  1021 
  1022 * tuned current_goals_markers semantics: begin / end goal avoids
  1023 printing empty lines;
  1024 
  1025 * removed prs and prs_fn hook, which was broken because it did not
  1026 include \n in its semantics, forcing writeln to add one
  1027 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1028 string -> unit if you really want to output text without newline;
  1029 
  1030 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1031 plain output, interface builders may have to enable 'isabelle_font'
  1032 mode to get Isabelle font glyphs as before;
  1033 
  1034 * refined token_translation interface; INCOMPATIBILITY: output length
  1035 now of type real instead of int;
  1036 
  1037 * theory loader actions may be traced via new ThyInfo.add_hook
  1038 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1039 your own database of information attached to *whole* theories -- as
  1040 opposed to intra-theory data slots offered via TheoryDataFun;
  1041 
  1042 * proper handling of dangling sort hypotheses (at last!);
  1043 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1044 extra sort hypotheses that can be witnessed from the type signature;
  1045 the force_strip_shyps flag is gone, any remaining shyps are simply
  1046 left in the theorem (with a warning issued by strip_shyps_warning);
  1047 
  1048 
  1049 
  1050 New in Isabelle98-1 (October 1998)
  1051 ----------------------------------
  1052 
  1053 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1054 
  1055 * several changes of automated proof tools;
  1056 
  1057 * HOL: major changes to the inductive and datatype packages, including
  1058 some minor incompatibilities of theory syntax;
  1059 
  1060 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1061 called `inj_on';
  1062 
  1063 * HOL: removed duplicate thms in Arith:
  1064   less_imp_add_less  should be replaced by  trans_less_add1
  1065   le_imp_add_le      should be replaced by  trans_le_add1
  1066 
  1067 * HOL: unary minus is now overloaded (new type constraints may be
  1068 required);
  1069 
  1070 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1071 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1072 now taken as an integer constant.
  1073 
  1074 * Pure: ML function 'theory_of' renamed to 'theory';
  1075 
  1076 
  1077 *** Proof tools ***
  1078 
  1079 * Simplifier:
  1080   1. Asm_full_simp_tac is now more aggressive.
  1081      1. It will sometimes reorient premises if that increases their power to
  1082         simplify.
  1083      2. It does no longer proceed strictly from left to right but may also
  1084         rotate premises to achieve further simplification.
  1085      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1086      old Asm_full_simp_tac in that it does not rotate premises.
  1087   2. The simplifier now knows a little bit about nat-arithmetic.
  1088 
  1089 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1090 allows for selected deletion of wrappers, by introduction of names for
  1091 wrapper functionals.  This implies that addbefore, addSbefore,
  1092 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1093 and that adding two tactics with the same name overwrites the first
  1094 one (emitting a warning).
  1095   type wrapper = (int -> tactic) -> (int -> tactic)
  1096   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1097   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1098   delWrapper, delSWrapper: claset *  string            -> claset
  1099   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1100 
  1101 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1102 semantics; addbefore now affects only the unsafe part of step_tac
  1103 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1104 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1105 by Force_tac;
  1106 
  1107 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1108 compWrapper; added safe wrapper (and access functions for it);
  1109 
  1110 * HOL/split_all_tac is now much faster and fails if there is nothing
  1111 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1112 and the names of the automatically generated variables have changed.
  1113 split_all_tac has moved within claset() from unsafe wrappers to safe
  1114 wrappers, which means that !!-bound variables are split much more
  1115 aggressively, and safe_tac and clarify_tac now split such variables.
  1116 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1117 Note: the same holds for record_split_tac, which does the job of
  1118 split_all_tac for record fields.
  1119 
  1120 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1121 permanently to the default simpset using Addsplits just like
  1122 Addsimps. They can be removed via Delsplits just like
  1123 Delsimps. Lower-case versions are also available.
  1124 
  1125 * HOL/Simplifier: The rule split_if is now part of the default
  1126 simpset. This means that the simplifier will eliminate all occurrences
  1127 of if-then-else in the conclusion of a goal. To prevent this, you can
  1128 either remove split_if completely from the default simpset by
  1129 `Delsplits [split_if]' or remove it in a specific call of the
  1130 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1131 other case splitting rules to/from the default simpset: every datatype
  1132 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1133 t is the name of the datatype).
  1134 
  1135 * Classical reasoner / Simplifier combination: new force_tac (and
  1136 derivatives Force_tac, force) combines rewriting and classical
  1137 reasoning (and whatever other tools) similarly to auto_tac, but is
  1138 aimed to solve the given subgoal completely.
  1139 
  1140 
  1141 *** General ***
  1142 
  1143 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1144 and `goalw': the theory is no longer needed as an explicit argument -
  1145 the current theory context is used; assumptions are no longer returned
  1146 at the ML-level unless one of them starts with ==> or !!; it is
  1147 recommended to convert to these new commands using isatool fixgoal
  1148 (backup your sources first!);
  1149 
  1150 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1151 the current theory context, and 'theory' to lookup stored theories;
  1152 
  1153 * new theory section 'locale' for declaring constants, assumptions and
  1154 definitions that have local scope;
  1155 
  1156 * new theory section 'nonterminals' for purely syntactic types;
  1157 
  1158 * new theory section 'setup' for generic ML setup functions
  1159 (e.g. package initialization);
  1160 
  1161 * the distribution now includes Isabelle icons: see
  1162 lib/logo/isabelle-{small,tiny}.xpm;
  1163 
  1164 * isatool install - install binaries with absolute references to
  1165 ISABELLE_HOME/bin;
  1166 
  1167 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1168 
  1169 * print mode 'emacs' reserved for Isamode;
  1170 
  1171 * support multiple print (ast) translations per constant name;
  1172 
  1173 * theorems involving oracles are now printed with a suffixed [!];
  1174 
  1175 
  1176 *** HOL ***
  1177 
  1178 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1179 
  1180 * HOL/inductive package reorganized and improved: now supports mutual
  1181 definitions such as
  1182 
  1183   inductive EVEN ODD
  1184     intrs
  1185       null "0 : EVEN"
  1186       oddI "n : EVEN ==> Suc n : ODD"
  1187       evenI "n : ODD ==> Suc n : EVEN"
  1188 
  1189 new theorem list "elims" contains an elimination rule for each of the
  1190 recursive sets; inductive definitions now handle disjunctive premises
  1191 correctly (also ZF);
  1192 
  1193 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1194 "mutual_induct" no longer exists - the induction rule is always
  1195 contained in "induct";
  1196 
  1197 
  1198 * HOL/datatype package re-implemented and greatly improved: now
  1199 supports mutually recursive datatypes such as
  1200 
  1201   datatype
  1202     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1203             | SUM ('a aexp) ('a aexp)
  1204             | DIFF ('a aexp) ('a aexp)
  1205             | NUM 'a
  1206   and
  1207     'a bexp = LESS ('a aexp) ('a aexp)
  1208             | AND ('a bexp) ('a bexp)
  1209             | OR ('a bexp) ('a bexp)
  1210 
  1211 as well as indirectly recursive datatypes such as
  1212 
  1213   datatype
  1214     ('a, 'b) term = Var 'a
  1215                   | App 'b ((('a, 'b) term) list)
  1216 
  1217 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1218 induction on mutually / indirectly recursive datatypes.
  1219 
  1220 Primrec equations are now stored in theory and can be accessed via
  1221 <function_name>.simps.
  1222 
  1223 INCOMPATIBILITIES:
  1224 
  1225   - Theories using datatypes must now have theory Datatype as an
  1226     ancestor.
  1227   - The specific <typename>.induct_tac no longer exists - use the
  1228     generic induct_tac instead.
  1229   - natE has been renamed to nat.exhaust - use exhaust_tac
  1230     instead of res_inst_tac ... natE. Note that the variable
  1231     names in nat.exhaust differ from the names in natE, this
  1232     may cause some "fragile" proofs to fail.
  1233   - The theorems split_<typename>_case and split_<typename>_case_asm
  1234     have been renamed to <typename>.split and <typename>.split_asm.
  1235   - Since default sorts of type variables are now handled correctly,
  1236     some datatype definitions may have to be annotated with explicit
  1237     sort constraints.
  1238   - Primrec definitions no longer require function name and type
  1239     of recursive argument.
  1240 
  1241 Consider using isatool fixdatatype to adapt your theories and proof
  1242 scripts to the new package (backup your sources first!).
  1243 
  1244 
  1245 * HOL/record package: considerably improved implementation; now
  1246 includes concrete syntax for record types, terms, updates; theorems
  1247 for surjective pairing and splitting !!-bound record variables; proof
  1248 support is as follows:
  1249 
  1250   1) standard conversions (selectors or updates applied to record
  1251 constructor terms) are part of the standard simpset;
  1252 
  1253   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1254 made part of standard simpset and claset via addIffs;
  1255 
  1256   3) a tactic for record field splitting (record_split_tac) is part of
  1257 the standard claset (addSWrapper);
  1258 
  1259 To get a better idea about these rules you may retrieve them via
  1260 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1261 the name of your record type.
  1262 
  1263 The split tactic 3) conceptually simplifies by the following rule:
  1264 
  1265   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1266 
  1267 Thus any record variable that is bound by meta-all will automatically
  1268 blow up into some record constructor term, consequently the
  1269 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1270 solve record problems automatically.
  1271 
  1272 
  1273 * reorganized the main HOL image: HOL/Integ and String loaded by
  1274 default; theory Main includes everything;
  1275 
  1276 * automatic simplification of integer sums and comparisons, using cancellation;
  1277 
  1278 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1279 
  1280 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1281 
  1282 * many new identities for unions, intersections, set difference, etc.;
  1283 
  1284 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1285 called split_if, split_split, split_sum_case and split_nat_case (to go
  1286 with add/delsplits);
  1287 
  1288 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1289 (?x::unit) = (); this is made part of the default simpset, which COULD
  1290 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1291 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1292 unit_abs_eta_conv is added in order to counter the effect of
  1293 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1294 %u.f();
  1295 
  1296 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1297 makes more sense);
  1298 
  1299 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1300   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1301   disjointness reasoning but breaking a few old proofs.
  1302 
  1303 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1304 to 'converse' from 'inverse' (for compatibility with ZF and some
  1305 literature);
  1306 
  1307 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1308 the well-founded relation;
  1309 
  1310 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1311     Compl A.  The "Compl" syntax remains available as input syntax for this
  1312     release ONLY.
  1313 
  1314 * HOL/Update: new theory of function updates:
  1315     f(a:=b) == %x. if x=a then b else f x
  1316 may also be iterated as in f(a:=b,c:=d,...);
  1317 
  1318 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1319 
  1320 * HOL/List:
  1321   - new function list_update written xs[i:=v] that updates the i-th
  1322     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1323   - new function `upt' written [i..j(] which generates the list
  1324     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1325     bound write [i..j], which is a shorthand for [i..j+1(].
  1326   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1327 
  1328 * HOL/Arith:
  1329   - removed 'pred' (predecessor) function;
  1330   - generalized some theorems about n-1;
  1331   - many new laws about "div" and "mod";
  1332   - new laws about greatest common divisors (see theory ex/Primes);
  1333 
  1334 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1335 instead of "inverse";
  1336 
  1337 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1338   of the multiset ordering;
  1339 
  1340 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1341   (not included by default);
  1342 
  1343 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1344 
  1345 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1346   programs, i.e. different program variables may have different types.
  1347 
  1348 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1349   [previously, this check worked only if the rewrite rule was unconditional]
  1350   Now rew can involve either definitions or equalities (either == or =).
  1351 
  1352 
  1353 *** ZF ***
  1354 
  1355 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1356   only the theorems proved on ZF.ML;
  1357 
  1358 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1359   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1360   disjointness reasoning but breaking a few old proofs.
  1361 
  1362 * ZF/Update: new theory of function updates
  1363     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1364   may also be iterated as in f(a:=b,c:=d,...);
  1365 
  1366 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1367 
  1368 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1369   [previously, this check worked only if the rewrite rule was unconditional]
  1370   Now rew can involve either definitions or equalities (either == or =).
  1371 
  1372 * case_tac provided for compatibility with HOL
  1373     (like the old excluded_middle_tac, but with subgoals swapped)
  1374 
  1375 
  1376 *** Internal programming interfaces ***
  1377 
  1378 * Pure: several new basic modules made available for general use, see
  1379 also src/Pure/README;
  1380 
  1381 * improved the theory data mechanism to support encapsulation (data
  1382 kind name replaced by private Object.kind, acting as authorization
  1383 key); new type-safe user interface via functor TheoryDataFun; generic
  1384 print_data function becomes basically useless;
  1385 
  1386 * removed global_names compatibility flag -- all theory declarations
  1387 are qualified by default;
  1388 
  1389 * module Pure/Syntax now offers quote / antiquote translation
  1390 functions (useful for Hoare logic etc. with implicit dependencies);
  1391 see HOL/ex/Antiquote for an example use;
  1392 
  1393 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1394 cterm -> thm;
  1395 
  1396 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1397 subgoal;
  1398 
  1399 * Display.print_goals function moved to Locale.print_goals;
  1400 
  1401 * standard print function for goals supports current_goals_markers
  1402 variable for marking begin of proof, end of proof, start of goal; the
  1403 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1404 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1405 for example;
  1406 
  1407 
  1408 
  1409 New in Isabelle98 (January 1998)
  1410 --------------------------------
  1411 
  1412 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1413 
  1414 * changed lexical syntax of terms / types: dots made part of long
  1415 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1416 
  1417 * simpset (and claset) reference variable replaced by functions
  1418 simpset / simpset_ref;
  1419 
  1420 * no longer supports theory aliases (via merge) and non-trivial
  1421 implicit merge of thms' signatures;
  1422 
  1423 * most internal names of constants changed due to qualified names;
  1424 
  1425 * changed Pure/Sequence interface (see Pure/seq.ML);
  1426 
  1427 
  1428 *** General Changes ***
  1429 
  1430 * hierachically structured name spaces (for consts, types, axms, thms
  1431 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1432 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1433 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1434 long_names for fully qualified output names; NOTE: ML programs
  1435 (special tactics, packages etc.) referring to internal names may have
  1436 to be adapted to cope with fully qualified names; in case of severe
  1437 backward campatibility problems try setting 'global_names' at compile
  1438 time to have enrything declared within a flat name space; one may also
  1439 fine tune name declarations in theories via the 'global' and 'local'
  1440 section;
  1441 
  1442 * reimplemented the implicit simpset and claset using the new anytype
  1443 data filed in signatures; references simpset:simpset ref etc. are
  1444 replaced by functions simpset:unit->simpset and
  1445 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1446 to patch your ML files accordingly;
  1447 
  1448 * HTML output now includes theory graph data for display with Java
  1449 applet or isatool browser; data generated automatically via isatool
  1450 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1451 
  1452 * defs may now be conditional; improved rewrite_goals_tac to handle
  1453 conditional equations;
  1454 
  1455 * defs now admits additional type arguments, using TYPE('a) syntax;
  1456 
  1457 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1458 creates a new theory node; implicit merge of thms' signatures is
  1459 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1460 transfer:theory->thm->thm in (rare) cases;
  1461 
  1462 * improved handling of draft signatures / theories; draft thms (and
  1463 ctyps, cterms) are automatically promoted to real ones;
  1464 
  1465 * slightly changed interfaces for oracles: admit many per theory, named
  1466 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1467 
  1468 * print_goals: optional output of const types (set show_consts and
  1469 show_types);
  1470 
  1471 * improved output of warnings (###) and errors (***);
  1472 
  1473 * subgoal_tac displays a warning if the new subgoal has type variables;
  1474 
  1475 * removed old README and Makefiles;
  1476 
  1477 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1478 
  1479 * removed obsolete init_pps and init_database;
  1480 
  1481 * deleted the obsolete tactical STATE, which was declared by
  1482     fun STATE tacfun st = tacfun st st;
  1483 
  1484 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1485 (which abbreviates $HOME);
  1486 
  1487 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1488 use isatool fixseq to adapt your ML programs (this works for fully
  1489 qualified references to the Sequence structure only!);
  1490 
  1491 * use_thy no longer requires writable current directory; it always
  1492 reloads .ML *and* .thy file, if either one is out of date;
  1493 
  1494 
  1495 *** Classical Reasoner ***
  1496 
  1497 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1498 tactics that use classical reasoning to simplify a subgoal without
  1499 splitting it into several subgoals;
  1500 
  1501 * Safe_tac: like safe_tac but uses the default claset;
  1502 
  1503 
  1504 *** Simplifier ***
  1505 
  1506 * added simplification meta rules:
  1507     (asm_)(full_)simplify: simpset -> thm -> thm;
  1508 
  1509 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1510 logics (again);
  1511 
  1512 * added prems argument to simplification procedures;
  1513 
  1514 * HOL, FOL, ZF: added infix function `addsplits':
  1515   instead of `<simpset> setloop (split_tac <thms>)'
  1516   you can simply write `<simpset> addsplits <thms>'
  1517 
  1518 
  1519 *** Syntax ***
  1520 
  1521 * TYPE('a) syntax for type reflection terms;
  1522 
  1523 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1524 
  1525 * pretty printer: changed order of mixfix annotation preference (again!);
  1526 
  1527 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1528 
  1529 
  1530 *** HOL ***
  1531 
  1532 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1533   with `addloop' of the simplifier to faciliate case splitting in premises.
  1534 
  1535 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1536 
  1537 * HOL/Auth: new protocol proofs including some for the Internet
  1538   protocol TLS;
  1539 
  1540 * HOL/Map: new theory of `maps' a la VDM;
  1541 
  1542 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1543 cancelling out common nat summands from =, <, <= (in)equalities, or
  1544 differences; simplification procedures nat_cancel_factor for
  1545 cancelling common factor from =, <, <= (in)equalities over natural
  1546 sums; nat_cancel contains both kinds of procedures, it is installed by
  1547 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1548 
  1549 * HOL/simplifier: terms of the form
  1550   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1551   are rewritten to
  1552   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1553   and those of the form
  1554   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1555   are rewritten to
  1556   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1557 
  1558 * HOL/datatype
  1559   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1560 
  1561   P(t_case f1 ... fn x) =
  1562      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1563         ...
  1564        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1565      )
  1566 
  1567   and a theorem `split_t_case_asm' of the form
  1568 
  1569   P(t_case f1 ... fn x) =
  1570     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1571         ...
  1572        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1573      )
  1574   which can be added to a simpset via `addsplits'. The existing theorems
  1575   expand_list_case and expand_option_case have been renamed to
  1576   split_list_case and split_option_case.
  1577 
  1578 * HOL/Arithmetic:
  1579   - `pred n' is automatically converted to `n-1'.
  1580     Users are strongly encouraged not to use `pred' any longer,
  1581     because it will disappear altogether at some point.
  1582   - Users are strongly encouraged to write "0 < n" rather than
  1583     "n ~= 0". Theorems and proof tools have been modified towards this
  1584     `standard'.
  1585 
  1586 * HOL/Lists:
  1587   the function "set_of_list" has been renamed "set" (and its theorems too);
  1588   the function "nth" now takes its arguments in the reverse order and
  1589   has acquired the infix notation "!" as in "xs!n".
  1590 
  1591 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1592 
  1593 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1594   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1595 
  1596 * HOL/record: extensible records with schematic structural subtyping
  1597 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1598 still lacks various theorems and concrete record syntax;
  1599 
  1600 
  1601 *** HOLCF ***
  1602 
  1603 * removed "axioms" and "generated by" sections;
  1604 
  1605 * replaced "ops" section by extended "consts" section, which is capable of
  1606   handling the continuous function space "->" directly;
  1607 
  1608 * domain package:
  1609   . proves theorems immediately and stores them in the theory,
  1610   . creates hierachical name space,
  1611   . now uses normal mixfix annotations (instead of cinfix...),
  1612   . minor changes to some names and values (for consistency),
  1613   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1614   . separator between mutual domain defs: changed "," to "and",
  1615   . improved handling of sort constraints;  now they have to
  1616     appear on the left-hand side of the equations only;
  1617 
  1618 * fixed LAM <x,y,zs>.b syntax;
  1619 
  1620 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1621 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1622 
  1623 
  1624 *** FOL and ZF ***
  1625 
  1626 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1627   with `addloop' of the simplifier to faciliate case splitting in premises.
  1628 
  1629 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1630 in HOL, they strip ALL and --> from proved theorems;
  1631 
  1632 
  1633 
  1634 New in Isabelle94-8 (May 1997)
  1635 ------------------------------
  1636 
  1637 *** General Changes ***
  1638 
  1639 * new utilities to build / run / maintain Isabelle etc. (in parts
  1640 still somewhat experimental); old Makefiles etc. still functional;
  1641 
  1642 * new 'Isabelle System Manual';
  1643 
  1644 * INSTALL text, together with ./configure and ./build scripts;
  1645 
  1646 * reimplemented type inference for greater efficiency, better error
  1647 messages and clean internal interface;
  1648 
  1649 * prlim command for dealing with lots of subgoals (an easier way of
  1650 setting goals_limit);
  1651 
  1652 
  1653 *** Syntax ***
  1654 
  1655 * supports alternative (named) syntax tables (parser and pretty
  1656 printer); internal interface is provided by add_modesyntax(_i);
  1657 
  1658 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1659 be used in conjunction with the Isabelle symbol font; uses the
  1660 "symbols" syntax table;
  1661 
  1662 * added token_translation interface (may translate name tokens in
  1663 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1664 the current print_mode); IMPORTANT: user print translation functions
  1665 are responsible for marking newly introduced bounds
  1666 (Syntax.mark_boundT);
  1667 
  1668 * token translations for modes "xterm" and "xterm_color" that display
  1669 names in bold, underline etc. or colors (which requires a color
  1670 version of xterm);
  1671 
  1672 * infixes may now be declared with names independent of their syntax;
  1673 
  1674 * added typed_print_translation (like print_translation, but may
  1675 access type of constant);
  1676 
  1677 
  1678 *** Classical Reasoner ***
  1679 
  1680 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1681 some limitations.  Blast_tac...
  1682   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1683   + ignores elimination rules that don't have the correct format
  1684         (the conclusion MUST be a formula variable)
  1685   + ignores types, which can make HOL proofs fail
  1686   + rules must not require higher-order unification, e.g. apply_type in ZF
  1687     [message "Function Var's argument not a bound variable" relates to this]
  1688   + its proof strategy is more general but can actually be slower
  1689 
  1690 * substitution with equality assumptions no longer permutes other
  1691 assumptions;
  1692 
  1693 * minor changes in semantics of addafter (now called addaltern); renamed
  1694 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1695 (and access functions for it);
  1696 
  1697 * improved combination of classical reasoner and simplifier:
  1698   + functions for handling clasimpsets
  1699   + improvement of addss: now the simplifier is called _after_ the
  1700     safe steps.
  1701   + safe variant of addss called addSss: uses safe simplifications
  1702     _during_ the safe steps. It is more complete as it allows multiple
  1703     instantiations of unknowns (e.g. with slow_tac).
  1704 
  1705 *** Simplifier ***
  1706 
  1707 * added interface for simplification procedures (functions that
  1708 produce *proven* rewrite rules on the fly, depending on current
  1709 redex);
  1710 
  1711 * ordering on terms as parameter (used for ordered rewriting);
  1712 
  1713 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1714 
  1715 * the solver is now split into a safe and an unsafe part.
  1716 This should be invisible for the normal user, except that the
  1717 functions setsolver and addsolver have been renamed to setSolver and
  1718 addSolver; added safe_asm_full_simp_tac;
  1719 
  1720 
  1721 *** HOL ***
  1722 
  1723 * a generic induction tactic `induct_tac' which works for all datatypes and
  1724 also for type `nat';
  1725 
  1726 * a generic case distinction tactic `exhaust_tac' which works for all
  1727 datatypes and also for type `nat';
  1728 
  1729 * each datatype comes with a function `size';
  1730 
  1731 * patterns in case expressions allow tuple patterns as arguments to
  1732 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1733 
  1734 * primrec now also works with type nat;
  1735 
  1736 * recdef: a new declaration form, allows general recursive functions to be
  1737 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1738 
  1739 * the constant for negation has been renamed from "not" to "Not" to
  1740 harmonize with FOL, ZF, LK, etc.;
  1741 
  1742 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1743 infinite lists;
  1744 
  1745 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1746 
  1747 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1748 problems in commutative rings, using axiomatic type classes for + and *;
  1749 
  1750 * more examples in HOL/MiniML and HOL/Auth;
  1751 
  1752 * more default rewrite rules for quantifiers, union/intersection;
  1753 
  1754 * a new constant `arbitrary == @x.False';
  1755 
  1756 * HOLCF/IOA replaces old HOL/IOA;
  1757 
  1758 * HOLCF changes: derived all rules and arities
  1759   + axiomatic type classes instead of classes
  1760   + typedef instead of faking type definitions
  1761   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1762   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1763   + eliminated the types void, one, tr
  1764   + use unit lift and bool lift (with translations) instead of one and tr
  1765   + eliminated blift from Lift3.thy (use Def instead of blift)
  1766   all eliminated rules are derived as theorems --> no visible changes ;
  1767 
  1768 
  1769 *** ZF ***
  1770 
  1771 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1772 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1773 as ZF_cs addSIs [equalityI];
  1774 
  1775 
  1776 
  1777 New in Isabelle94-7 (November 96)
  1778 ---------------------------------
  1779 
  1780 * allowing negative levels (as offsets) in prlev and choplev;
  1781 
  1782 * super-linear speedup for large simplifications;
  1783 
  1784 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1785 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1786 FAIL); can suppress it using the command Delsimps (ex_simps @
  1787 all_simps); De Morgan laws are also now included, by default;
  1788 
  1789 * improved printing of ==>  :  ~:
  1790 
  1791 * new object-logic "Sequents" adds linear logic, while replacing LK
  1792 and Modal (thanks to Sara Kalvala);
  1793 
  1794 * HOL/Auth: correctness proofs for authentication protocols;
  1795 
  1796 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1797 examples on HOL/Auth);
  1798 
  1799 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1800 the rewriter and classical reasoner simultaneously;
  1801 
  1802 * function uresult no longer returns theorems in "standard" format;
  1803 regain previous version by: val uresult = standard o uresult;
  1804 
  1805 
  1806 
  1807 New in Isabelle94-6
  1808 -------------------
  1809 
  1810 * oracles -- these establish an interface between Isabelle and trusted
  1811 external reasoners, which may deliver results as theorems;
  1812 
  1813 * proof objects (in particular record all uses of oracles);
  1814 
  1815 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1816 
  1817 * "constdefs" section in theory files;
  1818 
  1819 * "primrec" section (HOL) no longer requires names;
  1820 
  1821 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1822 
  1823 
  1824 
  1825 New in Isabelle94-5
  1826 -------------------
  1827 
  1828 * reduced space requirements;
  1829 
  1830 * automatic HTML generation from theories;
  1831 
  1832 * theory files no longer require "..." (quotes) around most types;
  1833 
  1834 * new examples, including two proofs of the Church-Rosser theorem;
  1835 
  1836 * non-curried (1994) version of HOL is no longer distributed;
  1837 
  1838 
  1839 
  1840 New in Isabelle94-4
  1841 -------------------
  1842 
  1843 * greatly reduced space requirements;
  1844 
  1845 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1846 
  1847 * searchable theorem database (see the section "Retrieving theorems" on
  1848 page 8 of the Reference Manual);
  1849 
  1850 * new examples, including Grabczewski's monumental case study of the
  1851 Axiom of Choice;
  1852 
  1853 * The previous version of HOL renamed to Old_HOL;
  1854 
  1855 * The new version of HOL (previously called CHOL) uses a curried syntax
  1856 for functions.  Application looks like f a b instead of f(a,b);
  1857 
  1858 * Mutually recursive inductive definitions finally work in HOL;
  1859 
  1860 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1861 translates to the operator "split";
  1862 
  1863 
  1864 
  1865 New in Isabelle94-3
  1866 -------------------
  1867 
  1868 * new infix operator, addss, allowing the classical reasoner to
  1869 perform simplification at each step of its search.  Example:
  1870         fast_tac (cs addss ss)
  1871 
  1872 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1873 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1874 look like (a,b) instead of <a,b>;
  1875 
  1876 * PLEASE NOTE: CHOL will eventually replace HOL!
  1877 
  1878 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1879 It translates to the operator "split".  A new theory of integers is available;
  1880 
  1881 * In ZF, integer numerals now denote two's-complement binary integers.
  1882 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1883 
  1884 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1885 of the Axiom of Choice;
  1886 
  1887 
  1888 
  1889 New in Isabelle94-2
  1890 -------------------
  1891 
  1892 * Significantly faster resolution;
  1893 
  1894 * the different sections in a .thy file can now be mixed and repeated
  1895 freely;
  1896 
  1897 * Database of theorems for FOL, HOL and ZF.  New
  1898 commands including qed, qed_goal and bind_thm store theorems in the database.
  1899 
  1900 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1901 a given theory (thms_of), or find out what theory a theorem was proved in
  1902 (theory_of_thm);
  1903 
  1904 * Bugs fixed in the inductive definition and datatype packages;
  1905 
  1906 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1907 and HOL_dup_cs obsolete;
  1908 
  1909 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1910 have been removed;
  1911 
  1912 * Simpler definition of function space in ZF;
  1913 
  1914 * new results about cardinal and ordinal arithmetic in ZF;
  1915 
  1916 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1917 types;
  1918 
  1919 
  1920 $Id$