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 "fx" 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, fz)

  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 $Id$