NEWS
author wenzelm
Thu Oct 04 11:28:30 2001 +0200 (2001-10-04)
changeset 11663 8a86409108fe
parent 11657 03c4a5c08a79
child 11690 cb64368fb405
permissions -rw-r--r--
* moved induct/cases attributes to Pure, added 'print_induct_rules' command;
     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 
    17 *** Isar ***
    18 
    19 * Isar/Pure: renamed "antecedent" case to "rule_context";
    20 
    21 * Isar/HOL: 'recdef' now fails on unfinished automated proofs, use
    22 "(permissive)" option to recover old behavior;
    23 
    24 * Isar/HOL: 'inductive' now longer features separate (collective)
    25 attributes for 'intros';
    26 
    27 * moved induct/cases attributes to Pure, added 'print_induct_rules'
    28 command;
    29 
    30 
    31 *** HOL ***
    32 
    33 * HOL: linorder_less_split superseded by linorder_cases;
    34 
    35 * HOL: added "The" definite description operator; move Hilbert's "Eps"
    36 to peripheral theory "Hilbert_Choice";
    37 
    38 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
    39 in this (rare) case use:
    40 
    41   delSWrapper "split_all_tac"
    42   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
    43 
    44 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
    45 MAY FAIL;
    46 
    47 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
    48 Isabelle's type classes, ^ on functions and relations has too general
    49 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
    50 necessary to attach explicit type constraints;
    51 
    52 * HOL: syntax translations now work properly with numerals and records
    53 expressions;
    54 
    55 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
    56 Florian Kammüller;
    57 
    58 * HOL: eliminated global items
    59 
    60   const "()" -> "Product_Type.Unity"
    61   type "unit" -> "Product_Type.unit"
    62 
    63 
    64 *** ZF ***
    65 
    66 * ZF: the integer library now covers quotients and remainders, with
    67 many laws relating division to addition, multiplication, etc.;
    68 
    69 
    70 *** General ***
    71 
    72 * Meta-level proof terms (by Stefan Berghofer), see also ref manual;
    73 
    74 * Classical reasoner: renamed addaltern to addafter, addSaltern to
    75 addSafter;
    76 
    77 * syntax: support non-oriented infixes;
    78 
    79 * print modes "type_brackets" and "no_type_brackets" control output of
    80 nested => (types); the default behavior is "brackets";
    81 
    82 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
    83 
    84 * system: Proof General keywords specification is now part of the
    85 Isabelle distribution (see etc/isar-keywords.el);
    86 
    87 * system: smart selection of Isabelle process versus Isabelle
    88 interface, accommodates case-insensitive file systems (e.g. HFS+); may
    89 run both "isabelle" and "Isabelle" even if file names are badly
    90 damaged (executable inspects the case of the first letter of its own
    91 name); added separate "isabelle-process" and "isabelle-interface";
    92 
    93 
    94 
    95 New in Isabelle99-2 (February 2001)
    96 -----------------------------------
    97 
    98 *** Overview of INCOMPATIBILITIES ***
    99 
   100 * HOL: please note that theories in the Library and elsewhere often use the
   101 new-style (Isar) format; to refer to their theorems in an ML script you must
   102 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   103 
   104 * HOL: inductive package no longer splits induction rule aggressively,
   105 but only as far as specified by the introductions given; the old
   106 format may be recovered via ML function complete_split_rule or attribute
   107 'split_rule (complete)';
   108 
   109 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   110 gfp_Tarski to gfp_unfold;
   111 
   112 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   113 
   114 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   115 relation); infix "^^" has been renamed "``"; infix "``" has been
   116 renamed "`"; "univalent" has been renamed "single_valued";
   117 
   118 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   119 operation;
   120 
   121 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   122 
   123 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   124 
   125 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   126 consequence, it is no longer monotonic wrt. the local goal context
   127 (which is now passed through the inductive cases);
   128 
   129 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   130 \<gg> to \<ggreater>;
   131 
   132 
   133 *** Document preparation ***
   134 
   135 * \isabellestyle{NAME} selects version of Isabelle output (currently
   136 available: are "it" for near math-mode best-style output, "sl" for
   137 slanted text style, and "tt" for plain type-writer; if no
   138 \isabellestyle command is given, output is according to slanted
   139 type-writer);
   140 
   141 * support sub/super scripts (for single symbols only), input syntax is
   142 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   143 
   144 * some more standard symbols; see Appendix A of the system manual for
   145 the complete list of symbols defined in isabellesym.sty;
   146 
   147 * improved isabelle style files; more abstract symbol implementation
   148 (should now use \isamath{...} and \isatext{...} in custom symbol
   149 definitions);
   150 
   151 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   152 state; Note that presentation of goal states does not conform to
   153 actual human-readable proof documents.  Please do not include goal
   154 states into document output unless you really know what you are doing!
   155 
   156 * proper indentation of antiquoted output with proportional LaTeX
   157 fonts;
   158 
   159 * no_document ML operator temporarily disables LaTeX document
   160 generation;
   161 
   162 * isatool unsymbolize tunes sources for plain ASCII communication;
   163 
   164 
   165 *** Isar ***
   166 
   167 * Pure: Isar now suffers initial goal statements to contain unbound
   168 schematic variables (this does not conform to actual readable proof
   169 documents, due to unpredictable outcome and non-compositional proof
   170 checking); users who know what they are doing may use schematic goals
   171 for Prolog-style synthesis of proven results;
   172 
   173 * Pure: assumption method (an implicit finishing) now handles actual
   174 rules as well;
   175 
   176 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   177 initial goal, declare "that" only as Pure intro (only for single
   178 steps); the "that" rule assumption may now be involved in implicit
   179 finishing, thus ".." becomes a feasible for trivial obtains;
   180 
   181 * Pure: default proof step now includes 'intro_classes'; thus trivial
   182 instance proofs may be performed by "..";
   183 
   184 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   185 statements as well;
   186 
   187 * Pure: more robust selection of calculational rules;
   188 
   189 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   190 rule (as well as the assumption rule);
   191 
   192 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   193 lemmas, using the graph browser tool;
   194 
   195 * Pure: predict failure of "show" in interactive mode;
   196 
   197 * Pure: 'thms_containing' now takes actual terms as arguments;
   198 
   199 * HOL: improved method 'induct' --- now handles non-atomic goals
   200 (potential INCOMPATIBILITY); tuned error handling;
   201 
   202 * HOL: cases and induct rules now provide explicit hints about the
   203 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   204 any remaining facts are inserted into the goal verbatim;
   205 
   206 * HOL: local contexts (aka cases) may now contain term bindings as
   207 well; the 'cases' and 'induct' methods new provide a ?case binding for
   208 the result to be shown in each case;
   209 
   210 * HOL: added 'recdef_tc' command;
   211 
   212 * isatool convert assists in eliminating legacy ML scripts;
   213 
   214 
   215 *** HOL ***
   216 
   217 * HOL/Library: a collection of generic theories to be used together
   218 with main HOL; the theory loader path already includes this directory
   219 by default; the following existing theories have been moved here:
   220 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   221 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   222 
   223 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   224 modelling and verification task performed in Isabelle/HOL +
   225 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   226 
   227 * HOL/Algebra: special summation operator SUM no longer exists, it has
   228 been replaced by setsum; infix 'assoc' now has priority 50 (like
   229 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   230 'domain', this makes the theory consistent with mathematical
   231 literature;
   232 
   233 * HOL basics: added overloaded operations "inverse" and "divide"
   234 (infix "/"), syntax for generic "abs" operation, generic summation
   235 operator \<Sum>;
   236 
   237 * HOL/typedef: simplified package, provide more useful rules (see also
   238 HOL/subset.thy);
   239 
   240 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   241 now expressed as a proper nested rule (old-style tactic scripts may
   242 require atomize_strip_tac to cope with non-atomic premises);
   243 
   244 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   245 to "split_conv" (old name still available for compatibility);
   246 
   247 * HOL: improved concrete syntax for strings (e.g. allows translation
   248 rules with string literals);
   249 
   250 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   251 and Fleuriot's mechanization of analysis;
   252 
   253 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   254 
   255 
   256 *** CTT ***
   257 
   258 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   259 "lam" is displayed as TWO lambda-symbols
   260 
   261 * CTT: theory Main now available, containing everything (that is, Bool
   262 and Arith);
   263 
   264 
   265 *** General ***
   266 
   267 * Pure: the Simplifier has been implemented properly as a derived rule
   268 outside of the actual kernel (at last!); the overall performance
   269 penalty in practical applications is about 50%, while reliability of
   270 the Isabelle inference kernel has been greatly improved;
   271 
   272 * print modes "brackets" and "no_brackets" control output of nested =>
   273 (types) and ==> (props); the default behaviour is "brackets";
   274 
   275 * Provers: fast_tac (and friends) now handle actual object-logic rules
   276 as assumptions as well;
   277 
   278 * system: support Poly/ML 4.0;
   279 
   280 * system: isatool install handles KDE version 1 or 2;
   281 
   282 
   283 
   284 New in Isabelle99-1 (October 2000)
   285 ----------------------------------
   286 
   287 *** Overview of INCOMPATIBILITIES ***
   288 
   289 * HOL: simplification of natural numbers is much changed; to partly
   290 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   291 issue the following ML commands:
   292 
   293   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   294   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   295 
   296 * HOL: simplification no longer dives into case-expressions; this is
   297 controlled by "t.weak_case_cong" for each datatype t;
   298 
   299 * HOL: nat_less_induct renamed to less_induct;
   300 
   301 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   302 fixsome to patch .thy and .ML sources automatically;
   303 
   304   select_equality  -> some_equality
   305   select_eq_Ex     -> some_eq_ex
   306   selectI2EX       -> someI2_ex
   307   selectI2         -> someI2
   308   selectI          -> someI
   309   select1_equality -> some1_equality
   310   Eps_sym_eq       -> some_sym_eq_trivial
   311   Eps_eq           -> some_eq_trivial
   312 
   313 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   314 
   315 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   316 instead);
   317 
   318 * HOL: the recursion equations generated by 'recdef' are now called
   319 f.simps instead of f.rules;
   320 
   321 * HOL: qed_spec_mp now also handles bounded ALL as well;
   322 
   323 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   324 sometimes be needed;
   325 
   326 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   327 
   328 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   329 
   330 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   331 product is now "<*>" instead of "Times"; the lexicographic product is
   332 now "<*lex*>" instead of "**";
   333 
   334 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   335 of main HOL, but was unused); better use HOL's datatype package;
   336 
   337 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   338 the old syntax may be recovered as follows:
   339 
   340   syntax (symbols)
   341     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   342       (infixl "\\<oplus>" 100)
   343 
   344 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   345 
   346 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   347 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   348 internally;
   349 
   350 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   351 changed from A/r to A//r;
   352 
   353 * ZF: new treatment of arithmetic (nat & int) may break some old
   354 proofs;
   355 
   356 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   357 rulify -> rule_format, elimify -> elim_format, ...);
   358 
   359 * Isar/Provers: intro/elim/dest attributes changed; renamed
   360 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   361 should have to change intro!! to intro? only); replaced "delrule" by
   362 "rule del";
   363 
   364 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   365 
   366 * Provers: strengthened force_tac by using new first_best_tac;
   367 
   368 * LaTeX document preparation: several changes of isabelle.sty (see
   369 lib/texinputs);
   370 
   371 
   372 *** Document preparation ***
   373 
   374 * formal comments (text blocks etc.) in new-style theories may now
   375 contain antiquotations of thm/prop/term/typ/text to be presented
   376 according to latex print mode; concrete syntax is like this:
   377 @{term[show_types] "f(x) = a + x"};
   378 
   379 * isatool mkdir provides easy setup of Isabelle session directories,
   380 including proper document sources;
   381 
   382 * generated LaTeX sources are now deleted after successful run
   383 (isatool document -c); may retain a copy somewhere else via -D option
   384 of isatool usedir;
   385 
   386 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   387 style files, achieving self-contained LaTeX sources and simplifying
   388 LaTeX debugging;
   389 
   390 * old-style theories now produce (crude) LaTeX output as well;
   391 
   392 * browser info session directories are now self-contained (may be put
   393 on WWW server seperately); improved graphs of nested sessions; removed
   394 graph for 'all sessions';
   395 
   396 * several improvements in isabelle style files; \isabellestyle{it}
   397 produces fake math mode output; \isamarkupheader is now \section by
   398 default; see lib/texinputs/isabelle.sty etc.;
   399 
   400 
   401 *** Isar ***
   402 
   403 * Isar/Pure: local results and corresponding term bindings are now
   404 subject to Hindley-Milner polymorphism (similar to ML); this
   405 accommodates incremental type-inference very nicely;
   406 
   407 * Isar/Pure: new derived language element 'obtain' supports
   408 generalized existence reasoning;
   409 
   410 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   411 support accumulation of results, without applying any rules yet;
   412 useful to collect intermediate results without explicit name
   413 references, and for use with transitivity rules with more than 2
   414 premises;
   415 
   416 * Isar/Pure: scalable support for case-analysis type proofs: new
   417 'case' language element refers to local contexts symbolically, as
   418 produced by certain proof methods; internally, case names are attached
   419 to theorems as "tags";
   420 
   421 * Isar/Pure: theory command 'hide' removes declarations from
   422 class/type/const name spaces;
   423 
   424 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   425 indicate potential overloading;
   426 
   427 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   428 
   429 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   430 "{a,b,c}" instead of {a,b,c};
   431 
   432 * Isar/Pure now provides its own version of intro/elim/dest
   433 attributes; useful for building new logics, but beware of confusion
   434 with the version in Provers/classical;
   435 
   436 * Isar/Pure: the local context of (non-atomic) goals is provided via
   437 case name 'antecedent';
   438 
   439 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   440 to the current context is now done automatically);
   441 
   442 * Isar/Pure: theory command 'method_setup' provides a simple interface
   443 for definining proof methods in ML;
   444 
   445 * Isar/Provers: intro/elim/dest attributes changed; renamed
   446 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   447 most cases, one should have to change intro!! to intro? only);
   448 replaced "delrule" by "rule del";
   449 
   450 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   451 'symmetric' attribute (the latter supercedes [RS sym]);
   452 
   453 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   454 method modifier); 'simp' method: 'only:' modifier removes loopers as
   455 well (including splits);
   456 
   457 * Isar/Provers: Simplifier and Classical methods now support all kind
   458 of modifiers used in the past, including 'cong', 'iff', etc.
   459 
   460 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   461 of Simplifier and Classical reasoner);
   462 
   463 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   464 now support named cases; major packages (inductive, datatype, primrec,
   465 recdef) support case names and properly name parameters;
   466 
   467 * Isar/HOL: new transitivity rules for substitution in inequalities --
   468 monotonicity conditions are extracted to be proven at end of
   469 calculations;
   470 
   471 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   472 method anyway;
   473 
   474 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   475 split_if split_if_asm; datatype package provides theorems foo.splits =
   476 foo.split foo.split_asm for each datatype;
   477 
   478 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   479 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   480 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   481 use "(cases (simplified))" method in proper proof texts);
   482 
   483 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   484 
   485 * Isar: names of theorems etc. may be natural numbers as well;
   486 
   487 * Isar: 'pr' command: optional arguments for goals_limit and
   488 ProofContext.prems_limit; no longer prints theory contexts, but only
   489 proof states;
   490 
   491 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   492 additional print modes to be specified; e.g. "pr(latex)" will print
   493 proof state according to the Isabelle LaTeX style;
   494 
   495 * Isar: improved support for emulating tactic scripts, including proof
   496 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   497 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   498 (for HOL datatypes);
   499 
   500 * Isar: simplified (more robust) goal selection of proof methods: 1st
   501 goal, all goals, or explicit goal specifier (tactic emulation); thus
   502 'proof method scripts' have to be in depth-first order;
   503 
   504 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   505 
   506 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   507 should instead use individual commands for printing items
   508 (print_commands, print_methods etc.);
   509 
   510 * Isar: added 'nothing' --- the empty list of theorems;
   511 
   512 
   513 *** HOL ***
   514 
   515 * HOL/MicroJava: formalization of a fragment of Java, together with a
   516 corresponding virtual machine and a specification of its bytecode
   517 verifier and a lightweight bytecode verifier, including proofs of
   518 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   519 Cornelia Pusch (see also the homepage of project Bali at
   520 http://isabelle.in.tum.de/Bali/);
   521 
   522 * HOL/Algebra: new theory of rings and univariate polynomials, by
   523 Clemens Ballarin;
   524 
   525 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   526 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   527 Rasmussen;
   528 
   529 * HOL/Lattice: fundamental concepts of lattice theory and order
   530 structures, including duals, properties of bounds versus algebraic
   531 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   532 Theorem for complete lattices etc.; may also serve as a demonstration
   533 for abstract algebraic reasoning using axiomatic type classes, and
   534 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   535 
   536 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   537 von Oheimb;
   538 
   539 * HOL/IMPP: extension of IMP with local variables and mutually
   540 recursive procedures, by David von Oheimb;
   541 
   542 * HOL/Lambda: converted into new-style theory and document;
   543 
   544 * HOL/ex/Multiquote: example of multiple nested quotations and
   545 anti-quotations -- basically a generalized version of de-Bruijn
   546 representation; very useful in avoiding lifting of operations;
   547 
   548 * HOL/record: added general record equality rule to simpset; fixed
   549 select-update simplification procedure to handle extended records as
   550 well; admit "r" as field name;
   551 
   552 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   553 other numeric types and also as the identity of groups, rings, etc.;
   554 
   555 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   556 Types nat and int belong to this axclass;
   557 
   558 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   559    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   560    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   561   two terms #m*u and #n*u are replaced by #(m+n)*u
   562     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   563   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   564     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   565 
   566 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   567 powerful prover for predicate logic but knows nothing of clasets; see
   568 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   569 
   570 * HOL: new version of "case_tac" subsumes both boolean case split and
   571 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   572 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   573 
   574 * HOL: simplification no longer dives into case-expressions: only the
   575 selector expression is simplified, but not the remaining arms; to
   576 enable full simplification of case-expressions for datatype t, you may
   577 remove t.weak_case_cong from the simpset, either globally (Delcongs
   578 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   579 
   580 * HOL/recdef: the recursion equations generated by 'recdef' for
   581 function 'f' are now called f.simps instead of f.rules; if all
   582 termination conditions are proved automatically, these simplification
   583 rules are added to the simpset, as in primrec; rules may be named
   584 individually as well, resulting in a separate list of theorems for
   585 each equation;
   586 
   587 * HOL/While is a new theory that provides a while-combinator. It
   588 permits the definition of tail-recursive functions without the
   589 provision of a termination measure. The latter is necessary once the
   590 invariant proof rule for while is applied.
   591 
   592 * HOL: new (overloaded) notation for the set of elements below/above
   593 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   594 
   595 * HOL: theorems impI, allI, ballI bound as "strip";
   596 
   597 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   598 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   599 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   600 
   601 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   602 
   603 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   604 main HOL, but was unused);
   605 
   606 * HOL: fewer consts declared as global (e.g. have to refer to
   607 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   608 
   609 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   610 in case of overlap with user translations (e.g. judgements over
   611 tuples); (note that the underlying logical represenation is still
   612 bogus);
   613 
   614 
   615 *** ZF ***
   616 
   617 * ZF: simplification automatically cancels common terms in arithmetic
   618 expressions over nat and int;
   619 
   620 * ZF: new treatment of nat to minimize type-checking: all operators
   621 coerce their operands to a natural number using the function natify,
   622 making the algebraic laws unconditional;
   623 
   624 * ZF: as above, for int: operators coerce their operands to an integer
   625 using the function intify;
   626 
   627 * ZF: the integer library now contains many of the usual laws for the
   628 orderings, including $<=, and monotonicity laws for $+ and $*;
   629 
   630 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   631 simplification;
   632 
   633 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   634 to the simplifier and classical reasoner simultaneously;
   635 
   636 
   637 *** General ***
   638 
   639 * Provers: blast_tac now handles actual object-logic rules as
   640 assumptions; note that auto_tac uses blast_tac internally as well;
   641 
   642 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   643 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   644 
   645 * Provers: delrules now handles destruct rules as well (no longer need
   646 explicit make_elim);
   647 
   648 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   649   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   650 use instead the strong form,
   651   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   652 in HOL, FOL and ZF the function cla_make_elim will create such rules
   653 from destruct-rules;
   654 
   655 * Provers: Simplifier.easy_setup provides a fast path to basic
   656 Simplifier setup for new object-logics;
   657 
   658 * Pure: AST translation rules no longer require constant head on LHS;
   659 
   660 * Pure: improved name spaces: ambiguous output is qualified; support
   661 for hiding of names;
   662 
   663 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   664 XSYMBOL_HOME; no longer need to do manual configuration in most
   665 situations;
   666 
   667 * system: compression of ML heaps images may now be controlled via -c
   668 option of isabelle and isatool usedir (currently only observed by
   669 Poly/ML);
   670 
   671 * system: isatool installfonts may handle X-Symbol fonts as well (very
   672 useful for remote X11);
   673 
   674 * system: provide TAGS file for Isabelle sources;
   675 
   676 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   677 order;
   678 
   679 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   680 timing flag supersedes proof_timing and Toplevel.trace;
   681 
   682 * ML: new combinators |>> and |>>> for incremental transformations
   683 with secondary results (e.g. certain theory extensions):
   684 
   685 * ML: PureThy.add_defs gets additional argument to indicate potential
   686 overloading (usually false);
   687 
   688 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   689 results;
   690 
   691 
   692 
   693 New in Isabelle99 (October 1999)
   694 --------------------------------
   695 
   696 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   697 
   698 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   699 are no longer simplified.  (This allows the simplifier to unfold recursive
   700 functional programs.)  To restore the old behaviour, declare
   701 
   702     Delcongs [if_weak_cong];
   703 
   704 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   705 complement;
   706 
   707 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   708 
   709 * HOL/datatype: mutual_induct_tac no longer exists --
   710   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   711 
   712 * HOL/typedef: fixed type inference for representing set; type
   713 arguments now have to occur explicitly on the rhs as type constraints;
   714 
   715 * ZF: The con_defs part of an inductive definition may no longer refer
   716 to constants declared in the same theory;
   717 
   718 * HOL, ZF: the function mk_cases, generated by the inductive
   719 definition package, has lost an argument.  To simplify its result, it
   720 uses the default simpset instead of a supplied list of theorems.
   721 
   722 * HOL/List: the constructors of type list are now Nil and Cons;
   723 
   724 * Simplifier: the type of the infix ML functions
   725         setSSolver addSSolver setSolver addSolver
   726 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   727 for packaging solvers. A solver is created via
   728         mk_solver: string -> (thm list -> int -> tactic) -> solver
   729 where the string argument is only a comment.
   730 
   731 
   732 *** Proof tools ***
   733 
   734 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   735 decision procedure for linear arithmetic. Currently it is used for
   736 types `nat', `int', and `real' in HOL (see below); it can, should and
   737 will be instantiated for other types and logics as well.
   738 
   739 * The simplifier now accepts rewrite rules with flexible heads, eg
   740      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   741   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   742   matching.
   743 
   744 
   745 *** General ***
   746 
   747 * New Isabelle/Isar subsystem provides an alternative to traditional
   748 tactical theorem proving; together with the ProofGeneral/isar user
   749 interface it offers an interactive environment for developing human
   750 readable proof documents (Isar == Intelligible semi-automated
   751 reasoning); for further information see isatool doc isar-ref,
   752 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   753 
   754 * improved and simplified presentation of theories: better HTML markup
   755 (including colors), graph views in several sizes; isatool usedir now
   756 provides a proper interface for user theories (via -P option); actual
   757 document preparation based on (PDF)LaTeX is available as well (for
   758 new-style theories only); see isatool doc system for more information;
   759 
   760 * native support for Proof General, both for classic Isabelle and
   761 Isabelle/Isar;
   762 
   763 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   764 using the graph browser tool;
   765 
   766 * Isabelle manuals now also available as PDF;
   767 
   768 * theory loader rewritten from scratch (may not be fully
   769 bug-compatible); old loadpath variable has been replaced by show_path,
   770 add_path, del_path, reset_path functions; new operations such as
   771 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   772 isatool doc ref);
   773 
   774 * improved isatool install: option -k creates KDE application icon,
   775 option -p DIR installs standalone binaries;
   776 
   777 * added ML_PLATFORM setting (useful for cross-platform installations);
   778 more robust handling of platform specific ML images for SML/NJ;
   779 
   780 * the settings environment is now statically scoped, i.e. it is never
   781 created again in sub-processes invoked from isabelle, isatool, or
   782 Isabelle;
   783 
   784 * path element specification '~~' refers to '$ISABELLE_HOME';
   785 
   786 * in locales, the "assumes" and "defines" parts may be omitted if
   787 empty;
   788 
   789 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   790 long arrows);
   791 
   792 * new print_mode "HTML";
   793 
   794 * new flag show_tags controls display of tags of theorems (which are
   795 basically just comments that may be attached by some tools);
   796 
   797 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   798 mode and goal output format:
   799 
   800 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   801 244c244
   802 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   803 ---
   804 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   805 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   806 181c181
   807 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   808 ---
   809 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   810 
   811 * function bind_thms stores lists of theorems (cf. bind_thm);
   812 
   813 * new shorthand tactics ftac, eatac, datac, fatac;
   814 
   815 * qed (and friends) now accept "" as result name; in that case the
   816 theorem is not stored, but proper checks and presentation of the
   817 result still apply;
   818 
   819 * theorem database now also indexes constants "Trueprop", "all",
   820 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   821 
   822 
   823 *** HOL ***
   824 
   825 ** HOL arithmetic **
   826 
   827 * There are now decision procedures for linear arithmetic over nat and
   828 int:
   829 
   830 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   831 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   832 are treated as atomic; subformulae not involving type `nat' or `int'
   833 are ignored; quantified subformulae are ignored unless they are
   834 positive universal or negative existential. The tactic has to be
   835 invoked by hand and can be a little bit slow. In particular, the
   836 running time is exponential in the number of occurrences of `min' and
   837 `max', and `-' on `nat'.
   838 
   839 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   840 (negated) (in)equalities among the premises and the conclusion into
   841 account (i.e. no compound formulae) and does not know about `min' and
   842 `max', and `-' on `nat'. It is fast and is used automatically by the
   843 simplifier.
   844 
   845 NB: At the moment, these decision procedures do not cope with mixed
   846 nat/int formulae where the two parts interact, such as `m < n ==>
   847 int(m) < int(n)'.
   848 
   849 * HOL/Numeral provides a generic theory of numerals (encoded
   850 efficiently as bit strings); setup for types nat/int/real is in place;
   851 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   852 int, existing theories and proof scripts may require a few additional
   853 type constraints;
   854 
   855 * integer division and remainder can now be performed on constant
   856 arguments;
   857 
   858 * many properties of integer multiplication, division and remainder
   859 are now available;
   860 
   861 * An interface to the Stanford Validity Checker (SVC) is available through the
   862 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   863 are proved automatically.  SVC must be installed separately, and its results
   864 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   865 invocation of the underlying oracle).  For SVC see
   866   http://verify.stanford.edu/SVC
   867 
   868 * IsaMakefile: the HOL-Real target now builds an actual image;
   869 
   870 
   871 ** HOL misc **
   872 
   873 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   874 (in Isabelle/Isar) -- by Gertrud Bauer;
   875 
   876 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   877 analysis for assembly languages with subtypes;
   878 
   879 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   880 -- avoids syntactic ambiguities and treats state, transition, and
   881 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   882 changed syntax and (many) tactics;
   883 
   884 * HOL/inductive: Now also handles more general introduction rules such
   885   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   886   theorems are now maintained within the theory (maintained via the
   887   "mono" attribute);
   888 
   889 * HOL/datatype: Now also handles arbitrarily branching datatypes
   890   (using function types) such as
   891 
   892   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   893 
   894 * HOL/record: record_simproc (part of the default simpset) takes care
   895 of selectors applied to updated records; record_split_tac is no longer
   896 part of the default claset; update_defs may now be removed from the
   897 simpset in many cases; COMPATIBILITY: old behavior achieved by
   898 
   899   claset_ref () := claset() addSWrapper record_split_wrapper;
   900   Delsimprocs [record_simproc]
   901 
   902 * HOL/typedef: fixed type inference for representing set; type
   903 arguments now have to occur explicitly on the rhs as type constraints;
   904 
   905 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   906 names rather than an ML expression;
   907 
   908 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   909 supplied later.  Program schemes can be defined, such as
   910     "While B C s = (if B s then While B C (C s) else s)"
   911 where the well-founded relation can be chosen after B and C have been given.
   912 
   913 * HOL/List: the constructors of type list are now Nil and Cons;
   914 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   915 course, ML tools referring to List.list.op # etc. have to be adapted;
   916 
   917 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   918 disabled by default; run isabelle with option -m HOL to get back to
   919 the original Gordon/HOL-style output;
   920 
   921 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   922 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   923 
   924 * HOL basic syntax simplified (more orthogonal): all variants of
   925 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   926 Eps operator is provided as well: "SOME x. P[x]";
   927 
   928 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   929 
   930 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   931 thus available for user theories;
   932 
   933 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   934 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   935 time;
   936 
   937 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   938 several times and then mp;
   939 
   940 
   941 *** LK ***
   942 
   943 * the notation <<...>> is now available as a notation for sequences of
   944 formulas;
   945 
   946 * the simplifier is now installed
   947 
   948 * the axiom system has been generalized (thanks to Soren Heilmann)
   949 
   950 * the classical reasoner now has a default rule database
   951 
   952 
   953 *** ZF ***
   954 
   955 * new primrec section allows primitive recursive functions to be given
   956 directly (as in HOL) over datatypes and the natural numbers;
   957 
   958 * new tactics induct_tac and exhaust_tac for induction (or case
   959 analysis) over datatypes and the natural numbers;
   960 
   961 * the datatype declaration of type T now defines the recursor T_rec;
   962 
   963 * simplification automatically does freeness reasoning for datatype
   964 constructors;
   965 
   966 * automatic type-inference, with AddTCs command to insert new
   967 type-checking rules;
   968 
   969 * datatype introduction rules are now added as Safe Introduction rules
   970 to the claset;
   971 
   972 * the syntax "if P then x else y" is now available in addition to
   973 if(P,x,y);
   974 
   975 
   976 *** Internal programming interfaces ***
   977 
   978 * tuned simplifier trace output; new flag debug_simp;
   979 
   980 * structures Vartab / Termtab (instances of TableFun) offer efficient
   981 tables indexed by indexname_ord / term_ord (compatible with aconv);
   982 
   983 * AxClass.axclass_tac lost the theory argument;
   984 
   985 * tuned current_goals_markers semantics: begin / end goal avoids
   986 printing empty lines;
   987 
   988 * removed prs and prs_fn hook, which was broken because it did not
   989 include \n in its semantics, forcing writeln to add one
   990 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   991 string -> unit if you really want to output text without newline;
   992 
   993 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   994 plain output, interface builders may have to enable 'isabelle_font'
   995 mode to get Isabelle font glyphs as before;
   996 
   997 * refined token_translation interface; INCOMPATIBILITY: output length
   998 now of type real instead of int;
   999 
  1000 * theory loader actions may be traced via new ThyInfo.add_hook
  1001 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1002 your own database of information attached to *whole* theories -- as
  1003 opposed to intra-theory data slots offered via TheoryDataFun;
  1004 
  1005 * proper handling of dangling sort hypotheses (at last!);
  1006 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1007 extra sort hypotheses that can be witnessed from the type signature;
  1008 the force_strip_shyps flag is gone, any remaining shyps are simply
  1009 left in the theorem (with a warning issued by strip_shyps_warning);
  1010 
  1011 
  1012 
  1013 New in Isabelle98-1 (October 1998)
  1014 ----------------------------------
  1015 
  1016 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1017 
  1018 * several changes of automated proof tools;
  1019 
  1020 * HOL: major changes to the inductive and datatype packages, including
  1021 some minor incompatibilities of theory syntax;
  1022 
  1023 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1024 called `inj_on';
  1025 
  1026 * HOL: removed duplicate thms in Arith:
  1027   less_imp_add_less  should be replaced by  trans_less_add1
  1028   le_imp_add_le      should be replaced by  trans_le_add1
  1029 
  1030 * HOL: unary minus is now overloaded (new type constraints may be
  1031 required);
  1032 
  1033 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1034 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1035 now taken as an integer constant.
  1036 
  1037 * Pure: ML function 'theory_of' renamed to 'theory';
  1038 
  1039 
  1040 *** Proof tools ***
  1041 
  1042 * Simplifier:
  1043   1. Asm_full_simp_tac is now more aggressive.
  1044      1. It will sometimes reorient premises if that increases their power to
  1045         simplify.
  1046      2. It does no longer proceed strictly from left to right but may also
  1047         rotate premises to achieve further simplification.
  1048      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1049      old Asm_full_simp_tac in that it does not rotate premises.
  1050   2. The simplifier now knows a little bit about nat-arithmetic.
  1051 
  1052 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1053 allows for selected deletion of wrappers, by introduction of names for
  1054 wrapper functionals.  This implies that addbefore, addSbefore,
  1055 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1056 and that adding two tactics with the same name overwrites the first
  1057 one (emitting a warning).
  1058   type wrapper = (int -> tactic) -> (int -> tactic)
  1059   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1060   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1061   delWrapper, delSWrapper: claset *  string            -> claset
  1062   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1063 
  1064 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1065 semantics; addbefore now affects only the unsafe part of step_tac
  1066 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1067 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1068 by Force_tac;
  1069 
  1070 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1071 compWrapper; added safe wrapper (and access functions for it);
  1072 
  1073 * HOL/split_all_tac is now much faster and fails if there is nothing
  1074 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1075 and the names of the automatically generated variables have changed.
  1076 split_all_tac has moved within claset() from unsafe wrappers to safe
  1077 wrappers, which means that !!-bound variables are split much more
  1078 aggressively, and safe_tac and clarify_tac now split such variables.
  1079 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1080 Note: the same holds for record_split_tac, which does the job of
  1081 split_all_tac for record fields.
  1082 
  1083 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1084 permanently to the default simpset using Addsplits just like
  1085 Addsimps. They can be removed via Delsplits just like
  1086 Delsimps. Lower-case versions are also available.
  1087 
  1088 * HOL/Simplifier: The rule split_if is now part of the default
  1089 simpset. This means that the simplifier will eliminate all occurrences
  1090 of if-then-else in the conclusion of a goal. To prevent this, you can
  1091 either remove split_if completely from the default simpset by
  1092 `Delsplits [split_if]' or remove it in a specific call of the
  1093 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1094 other case splitting rules to/from the default simpset: every datatype
  1095 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1096 t is the name of the datatype).
  1097 
  1098 * Classical reasoner / Simplifier combination: new force_tac (and
  1099 derivatives Force_tac, force) combines rewriting and classical
  1100 reasoning (and whatever other tools) similarly to auto_tac, but is
  1101 aimed to solve the given subgoal completely.
  1102 
  1103 
  1104 *** General ***
  1105 
  1106 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1107 and `goalw': the theory is no longer needed as an explicit argument -
  1108 the current theory context is used; assumptions are no longer returned
  1109 at the ML-level unless one of them starts with ==> or !!; it is
  1110 recommended to convert to these new commands using isatool fixgoal
  1111 (backup your sources first!);
  1112 
  1113 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1114 the current theory context, and 'theory' to lookup stored theories;
  1115 
  1116 * new theory section 'locale' for declaring constants, assumptions and
  1117 definitions that have local scope;
  1118 
  1119 * new theory section 'nonterminals' for purely syntactic types;
  1120 
  1121 * new theory section 'setup' for generic ML setup functions
  1122 (e.g. package initialization);
  1123 
  1124 * the distribution now includes Isabelle icons: see
  1125 lib/logo/isabelle-{small,tiny}.xpm;
  1126 
  1127 * isatool install - install binaries with absolute references to
  1128 ISABELLE_HOME/bin;
  1129 
  1130 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1131 
  1132 * print mode 'emacs' reserved for Isamode;
  1133 
  1134 * support multiple print (ast) translations per constant name;
  1135 
  1136 * theorems involving oracles are now printed with a suffixed [!];
  1137 
  1138 
  1139 *** HOL ***
  1140 
  1141 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1142 
  1143 * HOL/inductive package reorganized and improved: now supports mutual
  1144 definitions such as
  1145 
  1146   inductive EVEN ODD
  1147     intrs
  1148       null "0 : EVEN"
  1149       oddI "n : EVEN ==> Suc n : ODD"
  1150       evenI "n : ODD ==> Suc n : EVEN"
  1151 
  1152 new theorem list "elims" contains an elimination rule for each of the
  1153 recursive sets; inductive definitions now handle disjunctive premises
  1154 correctly (also ZF);
  1155 
  1156 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1157 "mutual_induct" no longer exists - the induction rule is always
  1158 contained in "induct";
  1159 
  1160 
  1161 * HOL/datatype package re-implemented and greatly improved: now
  1162 supports mutually recursive datatypes such as
  1163 
  1164   datatype
  1165     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1166             | SUM ('a aexp) ('a aexp)
  1167             | DIFF ('a aexp) ('a aexp)
  1168             | NUM 'a
  1169   and
  1170     'a bexp = LESS ('a aexp) ('a aexp)
  1171             | AND ('a bexp) ('a bexp)
  1172             | OR ('a bexp) ('a bexp)
  1173 
  1174 as well as indirectly recursive datatypes such as
  1175 
  1176   datatype
  1177     ('a, 'b) term = Var 'a
  1178                   | App 'b ((('a, 'b) term) list)
  1179 
  1180 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1181 induction on mutually / indirectly recursive datatypes.
  1182 
  1183 Primrec equations are now stored in theory and can be accessed via
  1184 <function_name>.simps.
  1185 
  1186 INCOMPATIBILITIES:
  1187 
  1188   - Theories using datatypes must now have theory Datatype as an
  1189     ancestor.
  1190   - The specific <typename>.induct_tac no longer exists - use the
  1191     generic induct_tac instead.
  1192   - natE has been renamed to nat.exhaust - use exhaust_tac
  1193     instead of res_inst_tac ... natE. Note that the variable
  1194     names in nat.exhaust differ from the names in natE, this
  1195     may cause some "fragile" proofs to fail.
  1196   - The theorems split_<typename>_case and split_<typename>_case_asm
  1197     have been renamed to <typename>.split and <typename>.split_asm.
  1198   - Since default sorts of type variables are now handled correctly,
  1199     some datatype definitions may have to be annotated with explicit
  1200     sort constraints.
  1201   - Primrec definitions no longer require function name and type
  1202     of recursive argument.
  1203 
  1204 Consider using isatool fixdatatype to adapt your theories and proof
  1205 scripts to the new package (backup your sources first!).
  1206 
  1207 
  1208 * HOL/record package: considerably improved implementation; now
  1209 includes concrete syntax for record types, terms, updates; theorems
  1210 for surjective pairing and splitting !!-bound record variables; proof
  1211 support is as follows:
  1212 
  1213   1) standard conversions (selectors or updates applied to record
  1214 constructor terms) are part of the standard simpset;
  1215 
  1216   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1217 made part of standard simpset and claset via addIffs;
  1218 
  1219   3) a tactic for record field splitting (record_split_tac) is part of
  1220 the standard claset (addSWrapper);
  1221 
  1222 To get a better idea about these rules you may retrieve them via
  1223 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1224 the name of your record type.
  1225 
  1226 The split tactic 3) conceptually simplifies by the following rule:
  1227 
  1228   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1229 
  1230 Thus any record variable that is bound by meta-all will automatically
  1231 blow up into some record constructor term, consequently the
  1232 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1233 solve record problems automatically.
  1234 
  1235 
  1236 * reorganized the main HOL image: HOL/Integ and String loaded by
  1237 default; theory Main includes everything;
  1238 
  1239 * automatic simplification of integer sums and comparisons, using cancellation;
  1240 
  1241 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1242 
  1243 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1244 
  1245 * many new identities for unions, intersections, set difference, etc.;
  1246 
  1247 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1248 called split_if, split_split, split_sum_case and split_nat_case (to go
  1249 with add/delsplits);
  1250 
  1251 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1252 (?x::unit) = (); this is made part of the default simpset, which COULD
  1253 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1254 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1255 unit_abs_eta_conv is added in order to counter the effect of
  1256 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1257 %u.f();
  1258 
  1259 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1260 makes more sense);
  1261 
  1262 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1263   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1264   disjointness reasoning but breaking a few old proofs.
  1265 
  1266 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1267 to 'converse' from 'inverse' (for compatibility with ZF and some
  1268 literature);
  1269 
  1270 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1271 the well-founded relation;
  1272 
  1273 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1274     Compl A.  The "Compl" syntax remains available as input syntax for this
  1275     release ONLY.
  1276 
  1277 * HOL/Update: new theory of function updates:
  1278     f(a:=b) == %x. if x=a then b else f x
  1279 may also be iterated as in f(a:=b,c:=d,...);
  1280 
  1281 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1282 
  1283 * HOL/List:
  1284   - new function list_update written xs[i:=v] that updates the i-th
  1285     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1286   - new function `upt' written [i..j(] which generates the list
  1287     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1288     bound write [i..j], which is a shorthand for [i..j+1(].
  1289   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1290 
  1291 * HOL/Arith:
  1292   - removed 'pred' (predecessor) function;
  1293   - generalized some theorems about n-1;
  1294   - many new laws about "div" and "mod";
  1295   - new laws about greatest common divisors (see theory ex/Primes);
  1296 
  1297 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1298 instead of "inverse";
  1299 
  1300 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1301   of the multiset ordering;
  1302 
  1303 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1304   (not included by default);
  1305 
  1306 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1307 
  1308 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1309   programs, i.e. different program variables may have different types.
  1310 
  1311 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1312   [previously, this check worked only if the rewrite rule was unconditional]
  1313   Now rew can involve either definitions or equalities (either == or =).
  1314 
  1315 
  1316 *** ZF ***
  1317 
  1318 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1319   only the theorems proved on ZF.ML;
  1320 
  1321 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1322   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1323   disjointness reasoning but breaking a few old proofs.
  1324 
  1325 * ZF/Update: new theory of function updates
  1326     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1327   may also be iterated as in f(a:=b,c:=d,...);
  1328 
  1329 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1330 
  1331 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1332   [previously, this check worked only if the rewrite rule was unconditional]
  1333   Now rew can involve either definitions or equalities (either == or =).
  1334 
  1335 * case_tac provided for compatibility with HOL
  1336     (like the old excluded_middle_tac, but with subgoals swapped)
  1337 
  1338 
  1339 *** Internal programming interfaces ***
  1340 
  1341 * Pure: several new basic modules made available for general use, see
  1342 also src/Pure/README;
  1343 
  1344 * improved the theory data mechanism to support encapsulation (data
  1345 kind name replaced by private Object.kind, acting as authorization
  1346 key); new type-safe user interface via functor TheoryDataFun; generic
  1347 print_data function becomes basically useless;
  1348 
  1349 * removed global_names compatibility flag -- all theory declarations
  1350 are qualified by default;
  1351 
  1352 * module Pure/Syntax now offers quote / antiquote translation
  1353 functions (useful for Hoare logic etc. with implicit dependencies);
  1354 see HOL/ex/Antiquote for an example use;
  1355 
  1356 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1357 cterm -> thm;
  1358 
  1359 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1360 subgoal;
  1361 
  1362 * Display.print_goals function moved to Locale.print_goals;
  1363 
  1364 * standard print function for goals supports current_goals_markers
  1365 variable for marking begin of proof, end of proof, start of goal; the
  1366 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1367 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1368 for example;
  1369 
  1370 
  1371 
  1372 New in Isabelle98 (January 1998)
  1373 --------------------------------
  1374 
  1375 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1376 
  1377 * changed lexical syntax of terms / types: dots made part of long
  1378 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1379 
  1380 * simpset (and claset) reference variable replaced by functions
  1381 simpset / simpset_ref;
  1382 
  1383 * no longer supports theory aliases (via merge) and non-trivial
  1384 implicit merge of thms' signatures;
  1385 
  1386 * most internal names of constants changed due to qualified names;
  1387 
  1388 * changed Pure/Sequence interface (see Pure/seq.ML);
  1389 
  1390 
  1391 *** General Changes ***
  1392 
  1393 * hierachically structured name spaces (for consts, types, axms, thms
  1394 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1395 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1396 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1397 long_names for fully qualified output names; NOTE: ML programs
  1398 (special tactics, packages etc.) referring to internal names may have
  1399 to be adapted to cope with fully qualified names; in case of severe
  1400 backward campatibility problems try setting 'global_names' at compile
  1401 time to have enrything declared within a flat name space; one may also
  1402 fine tune name declarations in theories via the 'global' and 'local'
  1403 section;
  1404 
  1405 * reimplemented the implicit simpset and claset using the new anytype
  1406 data filed in signatures; references simpset:simpset ref etc. are
  1407 replaced by functions simpset:unit->simpset and
  1408 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1409 to patch your ML files accordingly;
  1410 
  1411 * HTML output now includes theory graph data for display with Java
  1412 applet or isatool browser; data generated automatically via isatool
  1413 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1414 
  1415 * defs may now be conditional; improved rewrite_goals_tac to handle
  1416 conditional equations;
  1417 
  1418 * defs now admits additional type arguments, using TYPE('a) syntax;
  1419 
  1420 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1421 creates a new theory node; implicit merge of thms' signatures is
  1422 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1423 transfer:theory->thm->thm in (rare) cases;
  1424 
  1425 * improved handling of draft signatures / theories; draft thms (and
  1426 ctyps, cterms) are automatically promoted to real ones;
  1427 
  1428 * slightly changed interfaces for oracles: admit many per theory, named
  1429 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1430 
  1431 * print_goals: optional output of const types (set show_consts and
  1432 show_types);
  1433 
  1434 * improved output of warnings (###) and errors (***);
  1435 
  1436 * subgoal_tac displays a warning if the new subgoal has type variables;
  1437 
  1438 * removed old README and Makefiles;
  1439 
  1440 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1441 
  1442 * removed obsolete init_pps and init_database;
  1443 
  1444 * deleted the obsolete tactical STATE, which was declared by
  1445     fun STATE tacfun st = tacfun st st;
  1446 
  1447 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1448 (which abbreviates $HOME);
  1449 
  1450 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1451 use isatool fixseq to adapt your ML programs (this works for fully
  1452 qualified references to the Sequence structure only!);
  1453 
  1454 * use_thy no longer requires writable current directory; it always
  1455 reloads .ML *and* .thy file, if either one is out of date;
  1456 
  1457 
  1458 *** Classical Reasoner ***
  1459 
  1460 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1461 tactics that use classical reasoning to simplify a subgoal without
  1462 splitting it into several subgoals;
  1463 
  1464 * Safe_tac: like safe_tac but uses the default claset;
  1465 
  1466 
  1467 *** Simplifier ***
  1468 
  1469 * added simplification meta rules:
  1470     (asm_)(full_)simplify: simpset -> thm -> thm;
  1471 
  1472 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1473 logics (again);
  1474 
  1475 * added prems argument to simplification procedures;
  1476 
  1477 * HOL, FOL, ZF: added infix function `addsplits':
  1478   instead of `<simpset> setloop (split_tac <thms>)'
  1479   you can simply write `<simpset> addsplits <thms>'
  1480 
  1481 
  1482 *** Syntax ***
  1483 
  1484 * TYPE('a) syntax for type reflection terms;
  1485 
  1486 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1487 
  1488 * pretty printer: changed order of mixfix annotation preference (again!);
  1489 
  1490 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1491 
  1492 
  1493 *** HOL ***
  1494 
  1495 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1496   with `addloop' of the simplifier to faciliate case splitting in premises.
  1497 
  1498 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1499 
  1500 * HOL/Auth: new protocol proofs including some for the Internet
  1501   protocol TLS;
  1502 
  1503 * HOL/Map: new theory of `maps' a la VDM;
  1504 
  1505 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1506 cancelling out common nat summands from =, <, <= (in)equalities, or
  1507 differences; simplification procedures nat_cancel_factor for
  1508 cancelling common factor from =, <, <= (in)equalities over natural
  1509 sums; nat_cancel contains both kinds of procedures, it is installed by
  1510 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1511 
  1512 * HOL/simplifier: terms of the form
  1513   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1514   are rewritten to
  1515   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1516   and those of the form
  1517   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1518   are rewritten to
  1519   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1520 
  1521 * HOL/datatype
  1522   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1523 
  1524   P(t_case f1 ... fn x) =
  1525      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1526         ...
  1527        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1528      )
  1529 
  1530   and a theorem `split_t_case_asm' of the form
  1531 
  1532   P(t_case f1 ... fn x) =
  1533     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1534         ...
  1535        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1536      )
  1537   which can be added to a simpset via `addsplits'. The existing theorems
  1538   expand_list_case and expand_option_case have been renamed to
  1539   split_list_case and split_option_case.
  1540 
  1541 * HOL/Arithmetic:
  1542   - `pred n' is automatically converted to `n-1'.
  1543     Users are strongly encouraged not to use `pred' any longer,
  1544     because it will disappear altogether at some point.
  1545   - Users are strongly encouraged to write "0 < n" rather than
  1546     "n ~= 0". Theorems and proof tools have been modified towards this
  1547     `standard'.
  1548 
  1549 * HOL/Lists:
  1550   the function "set_of_list" has been renamed "set" (and its theorems too);
  1551   the function "nth" now takes its arguments in the reverse order and
  1552   has acquired the infix notation "!" as in "xs!n".
  1553 
  1554 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1555 
  1556 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1557   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1558 
  1559 * HOL/record: extensible records with schematic structural subtyping
  1560 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1561 still lacks various theorems and concrete record syntax;
  1562 
  1563 
  1564 *** HOLCF ***
  1565 
  1566 * removed "axioms" and "generated by" sections;
  1567 
  1568 * replaced "ops" section by extended "consts" section, which is capable of
  1569   handling the continuous function space "->" directly;
  1570 
  1571 * domain package:
  1572   . proves theorems immediately and stores them in the theory,
  1573   . creates hierachical name space,
  1574   . now uses normal mixfix annotations (instead of cinfix...),
  1575   . minor changes to some names and values (for consistency),
  1576   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1577   . separator between mutual domain defs: changed "," to "and",
  1578   . improved handling of sort constraints;  now they have to
  1579     appear on the left-hand side of the equations only;
  1580 
  1581 * fixed LAM <x,y,zs>.b syntax;
  1582 
  1583 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1584 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1585 
  1586 
  1587 *** FOL and ZF ***
  1588 
  1589 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1590   with `addloop' of the simplifier to faciliate case splitting in premises.
  1591 
  1592 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1593 in HOL, they strip ALL and --> from proved theorems;
  1594 
  1595 
  1596 
  1597 New in Isabelle94-8 (May 1997)
  1598 ------------------------------
  1599 
  1600 *** General Changes ***
  1601 
  1602 * new utilities to build / run / maintain Isabelle etc. (in parts
  1603 still somewhat experimental); old Makefiles etc. still functional;
  1604 
  1605 * new 'Isabelle System Manual';
  1606 
  1607 * INSTALL text, together with ./configure and ./build scripts;
  1608 
  1609 * reimplemented type inference for greater efficiency, better error
  1610 messages and clean internal interface;
  1611 
  1612 * prlim command for dealing with lots of subgoals (an easier way of
  1613 setting goals_limit);
  1614 
  1615 
  1616 *** Syntax ***
  1617 
  1618 * supports alternative (named) syntax tables (parser and pretty
  1619 printer); internal interface is provided by add_modesyntax(_i);
  1620 
  1621 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1622 be used in conjunction with the Isabelle symbol font; uses the
  1623 "symbols" syntax table;
  1624 
  1625 * added token_translation interface (may translate name tokens in
  1626 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1627 the current print_mode); IMPORTANT: user print translation functions
  1628 are responsible for marking newly introduced bounds
  1629 (Syntax.mark_boundT);
  1630 
  1631 * token translations for modes "xterm" and "xterm_color" that display
  1632 names in bold, underline etc. or colors (which requires a color
  1633 version of xterm);
  1634 
  1635 * infixes may now be declared with names independent of their syntax;
  1636 
  1637 * added typed_print_translation (like print_translation, but may
  1638 access type of constant);
  1639 
  1640 
  1641 *** Classical Reasoner ***
  1642 
  1643 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1644 some limitations.  Blast_tac...
  1645   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1646   + ignores elimination rules that don't have the correct format
  1647         (the conclusion MUST be a formula variable)
  1648   + ignores types, which can make HOL proofs fail
  1649   + rules must not require higher-order unification, e.g. apply_type in ZF
  1650     [message "Function Var's argument not a bound variable" relates to this]
  1651   + its proof strategy is more general but can actually be slower
  1652 
  1653 * substitution with equality assumptions no longer permutes other
  1654 assumptions;
  1655 
  1656 * minor changes in semantics of addafter (now called addaltern); renamed
  1657 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1658 (and access functions for it);
  1659 
  1660 * improved combination of classical reasoner and simplifier:
  1661   + functions for handling clasimpsets
  1662   + improvement of addss: now the simplifier is called _after_ the
  1663     safe steps.
  1664   + safe variant of addss called addSss: uses safe simplifications
  1665     _during_ the safe steps. It is more complete as it allows multiple
  1666     instantiations of unknowns (e.g. with slow_tac).
  1667 
  1668 *** Simplifier ***
  1669 
  1670 * added interface for simplification procedures (functions that
  1671 produce *proven* rewrite rules on the fly, depending on current
  1672 redex);
  1673 
  1674 * ordering on terms as parameter (used for ordered rewriting);
  1675 
  1676 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1677 
  1678 * the solver is now split into a safe and an unsafe part.
  1679 This should be invisible for the normal user, except that the
  1680 functions setsolver and addsolver have been renamed to setSolver and
  1681 addSolver; added safe_asm_full_simp_tac;
  1682 
  1683 
  1684 *** HOL ***
  1685 
  1686 * a generic induction tactic `induct_tac' which works for all datatypes and
  1687 also for type `nat';
  1688 
  1689 * a generic case distinction tactic `exhaust_tac' which works for all
  1690 datatypes and also for type `nat';
  1691 
  1692 * each datatype comes with a function `size';
  1693 
  1694 * patterns in case expressions allow tuple patterns as arguments to
  1695 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1696 
  1697 * primrec now also works with type nat;
  1698 
  1699 * recdef: a new declaration form, allows general recursive functions to be
  1700 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1701 
  1702 * the constant for negation has been renamed from "not" to "Not" to
  1703 harmonize with FOL, ZF, LK, etc.;
  1704 
  1705 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1706 infinite lists;
  1707 
  1708 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1709 
  1710 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1711 problems in commutative rings, using axiomatic type classes for + and *;
  1712 
  1713 * more examples in HOL/MiniML and HOL/Auth;
  1714 
  1715 * more default rewrite rules for quantifiers, union/intersection;
  1716 
  1717 * a new constant `arbitrary == @x.False';
  1718 
  1719 * HOLCF/IOA replaces old HOL/IOA;
  1720 
  1721 * HOLCF changes: derived all rules and arities
  1722   + axiomatic type classes instead of classes
  1723   + typedef instead of faking type definitions
  1724   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1725   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1726   + eliminated the types void, one, tr
  1727   + use unit lift and bool lift (with translations) instead of one and tr
  1728   + eliminated blift from Lift3.thy (use Def instead of blift)
  1729   all eliminated rules are derived as theorems --> no visible changes ;
  1730 
  1731 
  1732 *** ZF ***
  1733 
  1734 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1735 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1736 as ZF_cs addSIs [equalityI];
  1737 
  1738 
  1739 
  1740 New in Isabelle94-7 (November 96)
  1741 ---------------------------------
  1742 
  1743 * allowing negative levels (as offsets) in prlev and choplev;
  1744 
  1745 * super-linear speedup for large simplifications;
  1746 
  1747 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1748 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1749 FAIL); can suppress it using the command Delsimps (ex_simps @
  1750 all_simps); De Morgan laws are also now included, by default;
  1751 
  1752 * improved printing of ==>  :  ~:
  1753 
  1754 * new object-logic "Sequents" adds linear logic, while replacing LK
  1755 and Modal (thanks to Sara Kalvala);
  1756 
  1757 * HOL/Auth: correctness proofs for authentication protocols;
  1758 
  1759 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1760 examples on HOL/Auth);
  1761 
  1762 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1763 the rewriter and classical reasoner simultaneously;
  1764 
  1765 * function uresult no longer returns theorems in "standard" format;
  1766 regain previous version by: val uresult = standard o uresult;
  1767 
  1768 
  1769 
  1770 New in Isabelle94-6
  1771 -------------------
  1772 
  1773 * oracles -- these establish an interface between Isabelle and trusted
  1774 external reasoners, which may deliver results as theorems;
  1775 
  1776 * proof objects (in particular record all uses of oracles);
  1777 
  1778 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1779 
  1780 * "constdefs" section in theory files;
  1781 
  1782 * "primrec" section (HOL) no longer requires names;
  1783 
  1784 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1785 
  1786 
  1787 
  1788 New in Isabelle94-5
  1789 -------------------
  1790 
  1791 * reduced space requirements;
  1792 
  1793 * automatic HTML generation from theories;
  1794 
  1795 * theory files no longer require "..." (quotes) around most types;
  1796 
  1797 * new examples, including two proofs of the Church-Rosser theorem;
  1798 
  1799 * non-curried (1994) version of HOL is no longer distributed;
  1800 
  1801 
  1802 
  1803 New in Isabelle94-4
  1804 -------------------
  1805 
  1806 * greatly reduced space requirements;
  1807 
  1808 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1809 
  1810 * searchable theorem database (see the section "Retrieving theorems" on
  1811 page 8 of the Reference Manual);
  1812 
  1813 * new examples, including Grabczewski's monumental case study of the
  1814 Axiom of Choice;
  1815 
  1816 * The previous version of HOL renamed to Old_HOL;
  1817 
  1818 * The new version of HOL (previously called CHOL) uses a curried syntax
  1819 for functions.  Application looks like f a b instead of f(a,b);
  1820 
  1821 * Mutually recursive inductive definitions finally work in HOL;
  1822 
  1823 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1824 translates to the operator "split";
  1825 
  1826 
  1827 
  1828 New in Isabelle94-3
  1829 -------------------
  1830 
  1831 * new infix operator, addss, allowing the classical reasoner to
  1832 perform simplification at each step of its search.  Example:
  1833         fast_tac (cs addss ss)
  1834 
  1835 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1836 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1837 look like (a,b) instead of <a,b>;
  1838 
  1839 * PLEASE NOTE: CHOL will eventually replace HOL!
  1840 
  1841 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1842 It translates to the operator "split".  A new theory of integers is available;
  1843 
  1844 * In ZF, integer numerals now denote two's-complement binary integers.
  1845 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1846 
  1847 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1848 of the Axiom of Choice;
  1849 
  1850 
  1851 
  1852 New in Isabelle94-2
  1853 -------------------
  1854 
  1855 * Significantly faster resolution;
  1856 
  1857 * the different sections in a .thy file can now be mixed and repeated
  1858 freely;
  1859 
  1860 * Database of theorems for FOL, HOL and ZF.  New
  1861 commands including qed, qed_goal and bind_thm store theorems in the database.
  1862 
  1863 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1864 a given theory (thms_of), or find out what theory a theorem was proved in
  1865 (theory_of_thm);
  1866 
  1867 * Bugs fixed in the inductive definition and datatype packages;
  1868 
  1869 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1870 and HOL_dup_cs obsolete;
  1871 
  1872 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1873 have been removed;
  1874 
  1875 * Simpler definition of function space in ZF;
  1876 
  1877 * new results about cardinal and ordinal arithmetic in ZF;
  1878 
  1879 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1880 types;
  1881 
  1882 
  1883 $Id$