NEWS
author wenzelm
Wed Oct 03 20:58:27 2001 +0200 (2001-10-03)
changeset 11657 03c4a5c08a79
parent 11633 c8945e0dc00b
child 11663 8a86409108fe
permissions -rw-r--r--
*** empty log message ***
     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 
    28 *** HOL ***
    29 
    30 * HOL: linorder_less_split superseded by linorder_cases;
    31 
    32 * HOL: added "The" definite description operator; move Hilbert's "Eps"
    33 to peripheral theory "Hilbert_Choice";
    34 
    35 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
    36 in this (rare) case use:
    37 
    38   delSWrapper "split_all_tac"
    39   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
    40 
    41 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
    42 MAY FAIL;
    43 
    44 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
    45 Isabelle's type classes, ^ on functions and relations has too general
    46 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
    47 necessary to attach explicit type constraints;
    48 
    49 * HOL: syntax translations now work properly with numerals and records
    50 expressions;
    51 
    52 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
    53 Florian Kammüller;
    54 
    55 * HOL: eliminated global items
    56 
    57   const "()" -> "Product_Type.Unity"
    58   type "unit" -> "Product_Type.unit"
    59 
    60 
    61 *** ZF ***
    62 
    63 * ZF: the integer library now covers quotients and remainders, with
    64 many laws relating division to addition, multiplication, etc.;
    65 
    66 
    67 *** General ***
    68 
    69 * Meta-level proof terms (by Stefan Berghofer), see also ref manual;
    70 
    71 * Classical reasoner: renamed addaltern to addafter, addSaltern to
    72 addSafter;
    73 
    74 * syntax: support non-oriented infixes;
    75 
    76 * print modes "type_brackets" and "no_type_brackets" control output of
    77 nested => (types); the default behavior is "brackets";
    78 
    79 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
    80 
    81 * system: Proof General keywords specification is now part of the
    82 Isabelle distribution (see etc/isar-keywords.el);
    83 
    84 * system: smart selection of Isabelle process versus Isabelle
    85 interface, accommodates case-insensitive file systems (e.g. HFS+); may
    86 run both "isabelle" and "Isabelle" even if file names are badly
    87 damaged (executable inspects the case of the first letter of its own
    88 name); added separate "isabelle-process" and "isabelle-interface";
    89 
    90 
    91 
    92 New in Isabelle99-2 (February 2001)
    93 -----------------------------------
    94 
    95 *** Overview of INCOMPATIBILITIES ***
    96 
    97 * HOL: please note that theories in the Library and elsewhere often use the
    98 new-style (Isar) format; to refer to their theorems in an ML script you must
    99 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   100 
   101 * HOL: inductive package no longer splits induction rule aggressively,
   102 but only as far as specified by the introductions given; the old
   103 format may be recovered via ML function complete_split_rule or attribute
   104 'split_rule (complete)';
   105 
   106 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   107 gfp_Tarski to gfp_unfold;
   108 
   109 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   110 
   111 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   112 relation); infix "^^" has been renamed "``"; infix "``" has been
   113 renamed "`"; "univalent" has been renamed "single_valued";
   114 
   115 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   116 operation;
   117 
   118 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   119 
   120 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   121 
   122 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   123 consequence, it is no longer monotonic wrt. the local goal context
   124 (which is now passed through the inductive cases);
   125 
   126 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   127 \<gg> to \<ggreater>;
   128 
   129 
   130 *** Document preparation ***
   131 
   132 * \isabellestyle{NAME} selects version of Isabelle output (currently
   133 available: are "it" for near math-mode best-style output, "sl" for
   134 slanted text style, and "tt" for plain type-writer; if no
   135 \isabellestyle command is given, output is according to slanted
   136 type-writer);
   137 
   138 * support sub/super scripts (for single symbols only), input syntax is
   139 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   140 
   141 * some more standard symbols; see Appendix A of the system manual for
   142 the complete list of symbols defined in isabellesym.sty;
   143 
   144 * improved isabelle style files; more abstract symbol implementation
   145 (should now use \isamath{...} and \isatext{...} in custom symbol
   146 definitions);
   147 
   148 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   149 state; Note that presentation of goal states does not conform to
   150 actual human-readable proof documents.  Please do not include goal
   151 states into document output unless you really know what you are doing!
   152 
   153 * proper indentation of antiquoted output with proportional LaTeX
   154 fonts;
   155 
   156 * no_document ML operator temporarily disables LaTeX document
   157 generation;
   158 
   159 * isatool unsymbolize tunes sources for plain ASCII communication;
   160 
   161 
   162 *** Isar ***
   163 
   164 * Pure: Isar now suffers initial goal statements to contain unbound
   165 schematic variables (this does not conform to actual readable proof
   166 documents, due to unpredictable outcome and non-compositional proof
   167 checking); users who know what they are doing may use schematic goals
   168 for Prolog-style synthesis of proven results;
   169 
   170 * Pure: assumption method (an implicit finishing) now handles actual
   171 rules as well;
   172 
   173 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   174 initial goal, declare "that" only as Pure intro (only for single
   175 steps); the "that" rule assumption may now be involved in implicit
   176 finishing, thus ".." becomes a feasible for trivial obtains;
   177 
   178 * Pure: default proof step now includes 'intro_classes'; thus trivial
   179 instance proofs may be performed by "..";
   180 
   181 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   182 statements as well;
   183 
   184 * Pure: more robust selection of calculational rules;
   185 
   186 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   187 rule (as well as the assumption rule);
   188 
   189 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   190 lemmas, using the graph browser tool;
   191 
   192 * Pure: predict failure of "show" in interactive mode;
   193 
   194 * Pure: 'thms_containing' now takes actual terms as arguments;
   195 
   196 * HOL: improved method 'induct' --- now handles non-atomic goals
   197 (potential INCOMPATIBILITY); tuned error handling;
   198 
   199 * HOL: cases and induct rules now provide explicit hints about the
   200 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   201 any remaining facts are inserted into the goal verbatim;
   202 
   203 * HOL: local contexts (aka cases) may now contain term bindings as
   204 well; the 'cases' and 'induct' methods new provide a ?case binding for
   205 the result to be shown in each case;
   206 
   207 * HOL: added 'recdef_tc' command;
   208 
   209 * isatool convert assists in eliminating legacy ML scripts;
   210 
   211 
   212 *** HOL ***
   213 
   214 * HOL/Library: a collection of generic theories to be used together
   215 with main HOL; the theory loader path already includes this directory
   216 by default; the following existing theories have been moved here:
   217 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   218 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   219 
   220 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   221 modelling and verification task performed in Isabelle/HOL +
   222 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   223 
   224 * HOL/Algebra: special summation operator SUM no longer exists, it has
   225 been replaced by setsum; infix 'assoc' now has priority 50 (like
   226 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   227 'domain', this makes the theory consistent with mathematical
   228 literature;
   229 
   230 * HOL basics: added overloaded operations "inverse" and "divide"
   231 (infix "/"), syntax for generic "abs" operation, generic summation
   232 operator \<Sum>;
   233 
   234 * HOL/typedef: simplified package, provide more useful rules (see also
   235 HOL/subset.thy);
   236 
   237 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   238 now expressed as a proper nested rule (old-style tactic scripts may
   239 require atomize_strip_tac to cope with non-atomic premises);
   240 
   241 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   242 to "split_conv" (old name still available for compatibility);
   243 
   244 * HOL: improved concrete syntax for strings (e.g. allows translation
   245 rules with string literals);
   246 
   247 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   248 and Fleuriot's mechanization of analysis;
   249 
   250 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   251 
   252 
   253 *** CTT ***
   254 
   255 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   256 "lam" is displayed as TWO lambda-symbols
   257 
   258 * CTT: theory Main now available, containing everything (that is, Bool
   259 and Arith);
   260 
   261 
   262 *** General ***
   263 
   264 * Pure: the Simplifier has been implemented properly as a derived rule
   265 outside of the actual kernel (at last!); the overall performance
   266 penalty in practical applications is about 50%, while reliability of
   267 the Isabelle inference kernel has been greatly improved;
   268 
   269 * print modes "brackets" and "no_brackets" control output of nested =>
   270 (types) and ==> (props); the default behaviour is "brackets";
   271 
   272 * Provers: fast_tac (and friends) now handle actual object-logic rules
   273 as assumptions as well;
   274 
   275 * system: support Poly/ML 4.0;
   276 
   277 * system: isatool install handles KDE version 1 or 2;
   278 
   279 
   280 
   281 New in Isabelle99-1 (October 2000)
   282 ----------------------------------
   283 
   284 *** Overview of INCOMPATIBILITIES ***
   285 
   286 * HOL: simplification of natural numbers is much changed; to partly
   287 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   288 issue the following ML commands:
   289 
   290   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   291   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   292 
   293 * HOL: simplification no longer dives into case-expressions; this is
   294 controlled by "t.weak_case_cong" for each datatype t;
   295 
   296 * HOL: nat_less_induct renamed to less_induct;
   297 
   298 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   299 fixsome to patch .thy and .ML sources automatically;
   300 
   301   select_equality  -> some_equality
   302   select_eq_Ex     -> some_eq_ex
   303   selectI2EX       -> someI2_ex
   304   selectI2         -> someI2
   305   selectI          -> someI
   306   select1_equality -> some1_equality
   307   Eps_sym_eq       -> some_sym_eq_trivial
   308   Eps_eq           -> some_eq_trivial
   309 
   310 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   311 
   312 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   313 instead);
   314 
   315 * HOL: the recursion equations generated by 'recdef' are now called
   316 f.simps instead of f.rules;
   317 
   318 * HOL: qed_spec_mp now also handles bounded ALL as well;
   319 
   320 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   321 sometimes be needed;
   322 
   323 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   324 
   325 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   326 
   327 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   328 product is now "<*>" instead of "Times"; the lexicographic product is
   329 now "<*lex*>" instead of "**";
   330 
   331 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   332 of main HOL, but was unused); better use HOL's datatype package;
   333 
   334 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   335 the old syntax may be recovered as follows:
   336 
   337   syntax (symbols)
   338     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   339       (infixl "\\<oplus>" 100)
   340 
   341 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   342 
   343 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   344 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   345 internally;
   346 
   347 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   348 changed from A/r to A//r;
   349 
   350 * ZF: new treatment of arithmetic (nat & int) may break some old
   351 proofs;
   352 
   353 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   354 rulify -> rule_format, elimify -> elim_format, ...);
   355 
   356 * Isar/Provers: intro/elim/dest attributes changed; renamed
   357 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   358 should have to change intro!! to intro? only); replaced "delrule" by
   359 "rule del";
   360 
   361 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   362 
   363 * Provers: strengthened force_tac by using new first_best_tac;
   364 
   365 * LaTeX document preparation: several changes of isabelle.sty (see
   366 lib/texinputs);
   367 
   368 
   369 *** Document preparation ***
   370 
   371 * formal comments (text blocks etc.) in new-style theories may now
   372 contain antiquotations of thm/prop/term/typ/text to be presented
   373 according to latex print mode; concrete syntax is like this:
   374 @{term[show_types] "f(x) = a + x"};
   375 
   376 * isatool mkdir provides easy setup of Isabelle session directories,
   377 including proper document sources;
   378 
   379 * generated LaTeX sources are now deleted after successful run
   380 (isatool document -c); may retain a copy somewhere else via -D option
   381 of isatool usedir;
   382 
   383 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   384 style files, achieving self-contained LaTeX sources and simplifying
   385 LaTeX debugging;
   386 
   387 * old-style theories now produce (crude) LaTeX output as well;
   388 
   389 * browser info session directories are now self-contained (may be put
   390 on WWW server seperately); improved graphs of nested sessions; removed
   391 graph for 'all sessions';
   392 
   393 * several improvements in isabelle style files; \isabellestyle{it}
   394 produces fake math mode output; \isamarkupheader is now \section by
   395 default; see lib/texinputs/isabelle.sty etc.;
   396 
   397 
   398 *** Isar ***
   399 
   400 * Isar/Pure: local results and corresponding term bindings are now
   401 subject to Hindley-Milner polymorphism (similar to ML); this
   402 accommodates incremental type-inference very nicely;
   403 
   404 * Isar/Pure: new derived language element 'obtain' supports
   405 generalized existence reasoning;
   406 
   407 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   408 support accumulation of results, without applying any rules yet;
   409 useful to collect intermediate results without explicit name
   410 references, and for use with transitivity rules with more than 2
   411 premises;
   412 
   413 * Isar/Pure: scalable support for case-analysis type proofs: new
   414 'case' language element refers to local contexts symbolically, as
   415 produced by certain proof methods; internally, case names are attached
   416 to theorems as "tags";
   417 
   418 * Isar/Pure: theory command 'hide' removes declarations from
   419 class/type/const name spaces;
   420 
   421 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   422 indicate potential overloading;
   423 
   424 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   425 
   426 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   427 "{a,b,c}" instead of {a,b,c};
   428 
   429 * Isar/Pure now provides its own version of intro/elim/dest
   430 attributes; useful for building new logics, but beware of confusion
   431 with the version in Provers/classical;
   432 
   433 * Isar/Pure: the local context of (non-atomic) goals is provided via
   434 case name 'antecedent';
   435 
   436 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   437 to the current context is now done automatically);
   438 
   439 * Isar/Pure: theory command 'method_setup' provides a simple interface
   440 for definining proof methods in ML;
   441 
   442 * Isar/Provers: intro/elim/dest attributes changed; renamed
   443 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   444 most cases, one should have to change intro!! to intro? only);
   445 replaced "delrule" by "rule del";
   446 
   447 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   448 'symmetric' attribute (the latter supercedes [RS sym]);
   449 
   450 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   451 method modifier); 'simp' method: 'only:' modifier removes loopers as
   452 well (including splits);
   453 
   454 * Isar/Provers: Simplifier and Classical methods now support all kind
   455 of modifiers used in the past, including 'cong', 'iff', etc.
   456 
   457 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   458 of Simplifier and Classical reasoner);
   459 
   460 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   461 now support named cases; major packages (inductive, datatype, primrec,
   462 recdef) support case names and properly name parameters;
   463 
   464 * Isar/HOL: new transitivity rules for substitution in inequalities --
   465 monotonicity conditions are extracted to be proven at end of
   466 calculations;
   467 
   468 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   469 method anyway;
   470 
   471 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   472 split_if split_if_asm; datatype package provides theorems foo.splits =
   473 foo.split foo.split_asm for each datatype;
   474 
   475 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   476 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   477 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   478 use "(cases (simplified))" method in proper proof texts);
   479 
   480 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   481 
   482 * Isar: names of theorems etc. may be natural numbers as well;
   483 
   484 * Isar: 'pr' command: optional arguments for goals_limit and
   485 ProofContext.prems_limit; no longer prints theory contexts, but only
   486 proof states;
   487 
   488 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   489 additional print modes to be specified; e.g. "pr(latex)" will print
   490 proof state according to the Isabelle LaTeX style;
   491 
   492 * Isar: improved support for emulating tactic scripts, including proof
   493 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   494 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   495 (for HOL datatypes);
   496 
   497 * Isar: simplified (more robust) goal selection of proof methods: 1st
   498 goal, all goals, or explicit goal specifier (tactic emulation); thus
   499 'proof method scripts' have to be in depth-first order;
   500 
   501 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   502 
   503 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   504 should instead use individual commands for printing items
   505 (print_commands, print_methods etc.);
   506 
   507 * Isar: added 'nothing' --- the empty list of theorems;
   508 
   509 
   510 *** HOL ***
   511 
   512 * HOL/MicroJava: formalization of a fragment of Java, together with a
   513 corresponding virtual machine and a specification of its bytecode
   514 verifier and a lightweight bytecode verifier, including proofs of
   515 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   516 Cornelia Pusch (see also the homepage of project Bali at
   517 http://isabelle.in.tum.de/Bali/);
   518 
   519 * HOL/Algebra: new theory of rings and univariate polynomials, by
   520 Clemens Ballarin;
   521 
   522 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   523 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   524 Rasmussen;
   525 
   526 * HOL/Lattice: fundamental concepts of lattice theory and order
   527 structures, including duals, properties of bounds versus algebraic
   528 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   529 Theorem for complete lattices etc.; may also serve as a demonstration
   530 for abstract algebraic reasoning using axiomatic type classes, and
   531 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   532 
   533 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   534 von Oheimb;
   535 
   536 * HOL/IMPP: extension of IMP with local variables and mutually
   537 recursive procedures, by David von Oheimb;
   538 
   539 * HOL/Lambda: converted into new-style theory and document;
   540 
   541 * HOL/ex/Multiquote: example of multiple nested quotations and
   542 anti-quotations -- basically a generalized version of de-Bruijn
   543 representation; very useful in avoiding lifting of operations;
   544 
   545 * HOL/record: added general record equality rule to simpset; fixed
   546 select-update simplification procedure to handle extended records as
   547 well; admit "r" as field name;
   548 
   549 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   550 other numeric types and also as the identity of groups, rings, etc.;
   551 
   552 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   553 Types nat and int belong to this axclass;
   554 
   555 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   556    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   557    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   558   two terms #m*u and #n*u are replaced by #(m+n)*u
   559     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   560   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   561     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   562 
   563 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   564 powerful prover for predicate logic but knows nothing of clasets; see
   565 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   566 
   567 * HOL: new version of "case_tac" subsumes both boolean case split and
   568 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   569 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   570 
   571 * HOL: simplification no longer dives into case-expressions: only the
   572 selector expression is simplified, but not the remaining arms; to
   573 enable full simplification of case-expressions for datatype t, you may
   574 remove t.weak_case_cong from the simpset, either globally (Delcongs
   575 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   576 
   577 * HOL/recdef: the recursion equations generated by 'recdef' for
   578 function 'f' are now called f.simps instead of f.rules; if all
   579 termination conditions are proved automatically, these simplification
   580 rules are added to the simpset, as in primrec; rules may be named
   581 individually as well, resulting in a separate list of theorems for
   582 each equation;
   583 
   584 * HOL/While is a new theory that provides a while-combinator. It
   585 permits the definition of tail-recursive functions without the
   586 provision of a termination measure. The latter is necessary once the
   587 invariant proof rule for while is applied.
   588 
   589 * HOL: new (overloaded) notation for the set of elements below/above
   590 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   591 
   592 * HOL: theorems impI, allI, ballI bound as "strip";
   593 
   594 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   595 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   596 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   597 
   598 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   599 
   600 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   601 main HOL, but was unused);
   602 
   603 * HOL: fewer consts declared as global (e.g. have to refer to
   604 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   605 
   606 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   607 in case of overlap with user translations (e.g. judgements over
   608 tuples); (note that the underlying logical represenation is still
   609 bogus);
   610 
   611 
   612 *** ZF ***
   613 
   614 * ZF: simplification automatically cancels common terms in arithmetic
   615 expressions over nat and int;
   616 
   617 * ZF: new treatment of nat to minimize type-checking: all operators
   618 coerce their operands to a natural number using the function natify,
   619 making the algebraic laws unconditional;
   620 
   621 * ZF: as above, for int: operators coerce their operands to an integer
   622 using the function intify;
   623 
   624 * ZF: the integer library now contains many of the usual laws for the
   625 orderings, including $<=, and monotonicity laws for $+ and $*;
   626 
   627 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   628 simplification;
   629 
   630 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   631 to the simplifier and classical reasoner simultaneously;
   632 
   633 
   634 *** General ***
   635 
   636 * Provers: blast_tac now handles actual object-logic rules as
   637 assumptions; note that auto_tac uses blast_tac internally as well;
   638 
   639 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   640 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   641 
   642 * Provers: delrules now handles destruct rules as well (no longer need
   643 explicit make_elim);
   644 
   645 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   646   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   647 use instead the strong form,
   648   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   649 in HOL, FOL and ZF the function cla_make_elim will create such rules
   650 from destruct-rules;
   651 
   652 * Provers: Simplifier.easy_setup provides a fast path to basic
   653 Simplifier setup for new object-logics;
   654 
   655 * Pure: AST translation rules no longer require constant head on LHS;
   656 
   657 * Pure: improved name spaces: ambiguous output is qualified; support
   658 for hiding of names;
   659 
   660 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   661 XSYMBOL_HOME; no longer need to do manual configuration in most
   662 situations;
   663 
   664 * system: compression of ML heaps images may now be controlled via -c
   665 option of isabelle and isatool usedir (currently only observed by
   666 Poly/ML);
   667 
   668 * system: isatool installfonts may handle X-Symbol fonts as well (very
   669 useful for remote X11);
   670 
   671 * system: provide TAGS file for Isabelle sources;
   672 
   673 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   674 order;
   675 
   676 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   677 timing flag supersedes proof_timing and Toplevel.trace;
   678 
   679 * ML: new combinators |>> and |>>> for incremental transformations
   680 with secondary results (e.g. certain theory extensions):
   681 
   682 * ML: PureThy.add_defs gets additional argument to indicate potential
   683 overloading (usually false);
   684 
   685 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   686 results;
   687 
   688 
   689 
   690 New in Isabelle99 (October 1999)
   691 --------------------------------
   692 
   693 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   694 
   695 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   696 are no longer simplified.  (This allows the simplifier to unfold recursive
   697 functional programs.)  To restore the old behaviour, declare
   698 
   699     Delcongs [if_weak_cong];
   700 
   701 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   702 complement;
   703 
   704 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   705 
   706 * HOL/datatype: mutual_induct_tac no longer exists --
   707   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   708 
   709 * HOL/typedef: fixed type inference for representing set; type
   710 arguments now have to occur explicitly on the rhs as type constraints;
   711 
   712 * ZF: The con_defs part of an inductive definition may no longer refer
   713 to constants declared in the same theory;
   714 
   715 * HOL, ZF: the function mk_cases, generated by the inductive
   716 definition package, has lost an argument.  To simplify its result, it
   717 uses the default simpset instead of a supplied list of theorems.
   718 
   719 * HOL/List: the constructors of type list are now Nil and Cons;
   720 
   721 * Simplifier: the type of the infix ML functions
   722         setSSolver addSSolver setSolver addSolver
   723 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   724 for packaging solvers. A solver is created via
   725         mk_solver: string -> (thm list -> int -> tactic) -> solver
   726 where the string argument is only a comment.
   727 
   728 
   729 *** Proof tools ***
   730 
   731 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   732 decision procedure for linear arithmetic. Currently it is used for
   733 types `nat', `int', and `real' in HOL (see below); it can, should and
   734 will be instantiated for other types and logics as well.
   735 
   736 * The simplifier now accepts rewrite rules with flexible heads, eg
   737      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   738   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   739   matching.
   740 
   741 
   742 *** General ***
   743 
   744 * New Isabelle/Isar subsystem provides an alternative to traditional
   745 tactical theorem proving; together with the ProofGeneral/isar user
   746 interface it offers an interactive environment for developing human
   747 readable proof documents (Isar == Intelligible semi-automated
   748 reasoning); for further information see isatool doc isar-ref,
   749 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   750 
   751 * improved and simplified presentation of theories: better HTML markup
   752 (including colors), graph views in several sizes; isatool usedir now
   753 provides a proper interface for user theories (via -P option); actual
   754 document preparation based on (PDF)LaTeX is available as well (for
   755 new-style theories only); see isatool doc system for more information;
   756 
   757 * native support for Proof General, both for classic Isabelle and
   758 Isabelle/Isar;
   759 
   760 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   761 using the graph browser tool;
   762 
   763 * Isabelle manuals now also available as PDF;
   764 
   765 * theory loader rewritten from scratch (may not be fully
   766 bug-compatible); old loadpath variable has been replaced by show_path,
   767 add_path, del_path, reset_path functions; new operations such as
   768 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   769 isatool doc ref);
   770 
   771 * improved isatool install: option -k creates KDE application icon,
   772 option -p DIR installs standalone binaries;
   773 
   774 * added ML_PLATFORM setting (useful for cross-platform installations);
   775 more robust handling of platform specific ML images for SML/NJ;
   776 
   777 * the settings environment is now statically scoped, i.e. it is never
   778 created again in sub-processes invoked from isabelle, isatool, or
   779 Isabelle;
   780 
   781 * path element specification '~~' refers to '$ISABELLE_HOME';
   782 
   783 * in locales, the "assumes" and "defines" parts may be omitted if
   784 empty;
   785 
   786 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   787 long arrows);
   788 
   789 * new print_mode "HTML";
   790 
   791 * new flag show_tags controls display of tags of theorems (which are
   792 basically just comments that may be attached by some tools);
   793 
   794 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   795 mode and goal output format:
   796 
   797 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   798 244c244
   799 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   800 ---
   801 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   802 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   803 181c181
   804 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   805 ---
   806 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   807 
   808 * function bind_thms stores lists of theorems (cf. bind_thm);
   809 
   810 * new shorthand tactics ftac, eatac, datac, fatac;
   811 
   812 * qed (and friends) now accept "" as result name; in that case the
   813 theorem is not stored, but proper checks and presentation of the
   814 result still apply;
   815 
   816 * theorem database now also indexes constants "Trueprop", "all",
   817 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   818 
   819 
   820 *** HOL ***
   821 
   822 ** HOL arithmetic **
   823 
   824 * There are now decision procedures for linear arithmetic over nat and
   825 int:
   826 
   827 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   828 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   829 are treated as atomic; subformulae not involving type `nat' or `int'
   830 are ignored; quantified subformulae are ignored unless they are
   831 positive universal or negative existential. The tactic has to be
   832 invoked by hand and can be a little bit slow. In particular, the
   833 running time is exponential in the number of occurrences of `min' and
   834 `max', and `-' on `nat'.
   835 
   836 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   837 (negated) (in)equalities among the premises and the conclusion into
   838 account (i.e. no compound formulae) and does not know about `min' and
   839 `max', and `-' on `nat'. It is fast and is used automatically by the
   840 simplifier.
   841 
   842 NB: At the moment, these decision procedures do not cope with mixed
   843 nat/int formulae where the two parts interact, such as `m < n ==>
   844 int(m) < int(n)'.
   845 
   846 * HOL/Numeral provides a generic theory of numerals (encoded
   847 efficiently as bit strings); setup for types nat/int/real is in place;
   848 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   849 int, existing theories and proof scripts may require a few additional
   850 type constraints;
   851 
   852 * integer division and remainder can now be performed on constant
   853 arguments;
   854 
   855 * many properties of integer multiplication, division and remainder
   856 are now available;
   857 
   858 * An interface to the Stanford Validity Checker (SVC) is available through the
   859 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   860 are proved automatically.  SVC must be installed separately, and its results
   861 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   862 invocation of the underlying oracle).  For SVC see
   863   http://verify.stanford.edu/SVC
   864 
   865 * IsaMakefile: the HOL-Real target now builds an actual image;
   866 
   867 
   868 ** HOL misc **
   869 
   870 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   871 (in Isabelle/Isar) -- by Gertrud Bauer;
   872 
   873 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   874 analysis for assembly languages with subtypes;
   875 
   876 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   877 -- avoids syntactic ambiguities and treats state, transition, and
   878 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   879 changed syntax and (many) tactics;
   880 
   881 * HOL/inductive: Now also handles more general introduction rules such
   882   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   883   theorems are now maintained within the theory (maintained via the
   884   "mono" attribute);
   885 
   886 * HOL/datatype: Now also handles arbitrarily branching datatypes
   887   (using function types) such as
   888 
   889   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   890 
   891 * HOL/record: record_simproc (part of the default simpset) takes care
   892 of selectors applied to updated records; record_split_tac is no longer
   893 part of the default claset; update_defs may now be removed from the
   894 simpset in many cases; COMPATIBILITY: old behavior achieved by
   895 
   896   claset_ref () := claset() addSWrapper record_split_wrapper;
   897   Delsimprocs [record_simproc]
   898 
   899 * HOL/typedef: fixed type inference for representing set; type
   900 arguments now have to occur explicitly on the rhs as type constraints;
   901 
   902 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   903 names rather than an ML expression;
   904 
   905 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   906 supplied later.  Program schemes can be defined, such as
   907     "While B C s = (if B s then While B C (C s) else s)"
   908 where the well-founded relation can be chosen after B and C have been given.
   909 
   910 * HOL/List: the constructors of type list are now Nil and Cons;
   911 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   912 course, ML tools referring to List.list.op # etc. have to be adapted;
   913 
   914 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   915 disabled by default; run isabelle with option -m HOL to get back to
   916 the original Gordon/HOL-style output;
   917 
   918 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   919 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   920 
   921 * HOL basic syntax simplified (more orthogonal): all variants of
   922 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   923 Eps operator is provided as well: "SOME x. P[x]";
   924 
   925 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   926 
   927 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   928 thus available for user theories;
   929 
   930 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   931 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   932 time;
   933 
   934 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   935 several times and then mp;
   936 
   937 
   938 *** LK ***
   939 
   940 * the notation <<...>> is now available as a notation for sequences of
   941 formulas;
   942 
   943 * the simplifier is now installed
   944 
   945 * the axiom system has been generalized (thanks to Soren Heilmann)
   946 
   947 * the classical reasoner now has a default rule database
   948 
   949 
   950 *** ZF ***
   951 
   952 * new primrec section allows primitive recursive functions to be given
   953 directly (as in HOL) over datatypes and the natural numbers;
   954 
   955 * new tactics induct_tac and exhaust_tac for induction (or case
   956 analysis) over datatypes and the natural numbers;
   957 
   958 * the datatype declaration of type T now defines the recursor T_rec;
   959 
   960 * simplification automatically does freeness reasoning for datatype
   961 constructors;
   962 
   963 * automatic type-inference, with AddTCs command to insert new
   964 type-checking rules;
   965 
   966 * datatype introduction rules are now added as Safe Introduction rules
   967 to the claset;
   968 
   969 * the syntax "if P then x else y" is now available in addition to
   970 if(P,x,y);
   971 
   972 
   973 *** Internal programming interfaces ***
   974 
   975 * tuned simplifier trace output; new flag debug_simp;
   976 
   977 * structures Vartab / Termtab (instances of TableFun) offer efficient
   978 tables indexed by indexname_ord / term_ord (compatible with aconv);
   979 
   980 * AxClass.axclass_tac lost the theory argument;
   981 
   982 * tuned current_goals_markers semantics: begin / end goal avoids
   983 printing empty lines;
   984 
   985 * removed prs and prs_fn hook, which was broken because it did not
   986 include \n in its semantics, forcing writeln to add one
   987 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   988 string -> unit if you really want to output text without newline;
   989 
   990 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   991 plain output, interface builders may have to enable 'isabelle_font'
   992 mode to get Isabelle font glyphs as before;
   993 
   994 * refined token_translation interface; INCOMPATIBILITY: output length
   995 now of type real instead of int;
   996 
   997 * theory loader actions may be traced via new ThyInfo.add_hook
   998 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   999 your own database of information attached to *whole* theories -- as
  1000 opposed to intra-theory data slots offered via TheoryDataFun;
  1001 
  1002 * proper handling of dangling sort hypotheses (at last!);
  1003 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1004 extra sort hypotheses that can be witnessed from the type signature;
  1005 the force_strip_shyps flag is gone, any remaining shyps are simply
  1006 left in the theorem (with a warning issued by strip_shyps_warning);
  1007 
  1008 
  1009 
  1010 New in Isabelle98-1 (October 1998)
  1011 ----------------------------------
  1012 
  1013 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1014 
  1015 * several changes of automated proof tools;
  1016 
  1017 * HOL: major changes to the inductive and datatype packages, including
  1018 some minor incompatibilities of theory syntax;
  1019 
  1020 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1021 called `inj_on';
  1022 
  1023 * HOL: removed duplicate thms in Arith:
  1024   less_imp_add_less  should be replaced by  trans_less_add1
  1025   le_imp_add_le      should be replaced by  trans_le_add1
  1026 
  1027 * HOL: unary minus is now overloaded (new type constraints may be
  1028 required);
  1029 
  1030 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1031 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1032 now taken as an integer constant.
  1033 
  1034 * Pure: ML function 'theory_of' renamed to 'theory';
  1035 
  1036 
  1037 *** Proof tools ***
  1038 
  1039 * Simplifier:
  1040   1. Asm_full_simp_tac is now more aggressive.
  1041      1. It will sometimes reorient premises if that increases their power to
  1042         simplify.
  1043      2. It does no longer proceed strictly from left to right but may also
  1044         rotate premises to achieve further simplification.
  1045      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1046      old Asm_full_simp_tac in that it does not rotate premises.
  1047   2. The simplifier now knows a little bit about nat-arithmetic.
  1048 
  1049 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1050 allows for selected deletion of wrappers, by introduction of names for
  1051 wrapper functionals.  This implies that addbefore, addSbefore,
  1052 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1053 and that adding two tactics with the same name overwrites the first
  1054 one (emitting a warning).
  1055   type wrapper = (int -> tactic) -> (int -> tactic)
  1056   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1057   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1058   delWrapper, delSWrapper: claset *  string            -> claset
  1059   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1060 
  1061 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1062 semantics; addbefore now affects only the unsafe part of step_tac
  1063 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1064 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1065 by Force_tac;
  1066 
  1067 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1068 compWrapper; added safe wrapper (and access functions for it);
  1069 
  1070 * HOL/split_all_tac is now much faster and fails if there is nothing
  1071 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1072 and the names of the automatically generated variables have changed.
  1073 split_all_tac has moved within claset() from unsafe wrappers to safe
  1074 wrappers, which means that !!-bound variables are split much more
  1075 aggressively, and safe_tac and clarify_tac now split such variables.
  1076 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1077 Note: the same holds for record_split_tac, which does the job of
  1078 split_all_tac for record fields.
  1079 
  1080 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1081 permanently to the default simpset using Addsplits just like
  1082 Addsimps. They can be removed via Delsplits just like
  1083 Delsimps. Lower-case versions are also available.
  1084 
  1085 * HOL/Simplifier: The rule split_if is now part of the default
  1086 simpset. This means that the simplifier will eliminate all occurrences
  1087 of if-then-else in the conclusion of a goal. To prevent this, you can
  1088 either remove split_if completely from the default simpset by
  1089 `Delsplits [split_if]' or remove it in a specific call of the
  1090 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1091 other case splitting rules to/from the default simpset: every datatype
  1092 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1093 t is the name of the datatype).
  1094 
  1095 * Classical reasoner / Simplifier combination: new force_tac (and
  1096 derivatives Force_tac, force) combines rewriting and classical
  1097 reasoning (and whatever other tools) similarly to auto_tac, but is
  1098 aimed to solve the given subgoal completely.
  1099 
  1100 
  1101 *** General ***
  1102 
  1103 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1104 and `goalw': the theory is no longer needed as an explicit argument -
  1105 the current theory context is used; assumptions are no longer returned
  1106 at the ML-level unless one of them starts with ==> or !!; it is
  1107 recommended to convert to these new commands using isatool fixgoal
  1108 (backup your sources first!);
  1109 
  1110 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1111 the current theory context, and 'theory' to lookup stored theories;
  1112 
  1113 * new theory section 'locale' for declaring constants, assumptions and
  1114 definitions that have local scope;
  1115 
  1116 * new theory section 'nonterminals' for purely syntactic types;
  1117 
  1118 * new theory section 'setup' for generic ML setup functions
  1119 (e.g. package initialization);
  1120 
  1121 * the distribution now includes Isabelle icons: see
  1122 lib/logo/isabelle-{small,tiny}.xpm;
  1123 
  1124 * isatool install - install binaries with absolute references to
  1125 ISABELLE_HOME/bin;
  1126 
  1127 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1128 
  1129 * print mode 'emacs' reserved for Isamode;
  1130 
  1131 * support multiple print (ast) translations per constant name;
  1132 
  1133 * theorems involving oracles are now printed with a suffixed [!];
  1134 
  1135 
  1136 *** HOL ***
  1137 
  1138 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1139 
  1140 * HOL/inductive package reorganized and improved: now supports mutual
  1141 definitions such as
  1142 
  1143   inductive EVEN ODD
  1144     intrs
  1145       null "0 : EVEN"
  1146       oddI "n : EVEN ==> Suc n : ODD"
  1147       evenI "n : ODD ==> Suc n : EVEN"
  1148 
  1149 new theorem list "elims" contains an elimination rule for each of the
  1150 recursive sets; inductive definitions now handle disjunctive premises
  1151 correctly (also ZF);
  1152 
  1153 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1154 "mutual_induct" no longer exists - the induction rule is always
  1155 contained in "induct";
  1156 
  1157 
  1158 * HOL/datatype package re-implemented and greatly improved: now
  1159 supports mutually recursive datatypes such as
  1160 
  1161   datatype
  1162     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1163             | SUM ('a aexp) ('a aexp)
  1164             | DIFF ('a aexp) ('a aexp)
  1165             | NUM 'a
  1166   and
  1167     'a bexp = LESS ('a aexp) ('a aexp)
  1168             | AND ('a bexp) ('a bexp)
  1169             | OR ('a bexp) ('a bexp)
  1170 
  1171 as well as indirectly recursive datatypes such as
  1172 
  1173   datatype
  1174     ('a, 'b) term = Var 'a
  1175                   | App 'b ((('a, 'b) term) list)
  1176 
  1177 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1178 induction on mutually / indirectly recursive datatypes.
  1179 
  1180 Primrec equations are now stored in theory and can be accessed via
  1181 <function_name>.simps.
  1182 
  1183 INCOMPATIBILITIES:
  1184 
  1185   - Theories using datatypes must now have theory Datatype as an
  1186     ancestor.
  1187   - The specific <typename>.induct_tac no longer exists - use the
  1188     generic induct_tac instead.
  1189   - natE has been renamed to nat.exhaust - use exhaust_tac
  1190     instead of res_inst_tac ... natE. Note that the variable
  1191     names in nat.exhaust differ from the names in natE, this
  1192     may cause some "fragile" proofs to fail.
  1193   - The theorems split_<typename>_case and split_<typename>_case_asm
  1194     have been renamed to <typename>.split and <typename>.split_asm.
  1195   - Since default sorts of type variables are now handled correctly,
  1196     some datatype definitions may have to be annotated with explicit
  1197     sort constraints.
  1198   - Primrec definitions no longer require function name and type
  1199     of recursive argument.
  1200 
  1201 Consider using isatool fixdatatype to adapt your theories and proof
  1202 scripts to the new package (backup your sources first!).
  1203 
  1204 
  1205 * HOL/record package: considerably improved implementation; now
  1206 includes concrete syntax for record types, terms, updates; theorems
  1207 for surjective pairing and splitting !!-bound record variables; proof
  1208 support is as follows:
  1209 
  1210   1) standard conversions (selectors or updates applied to record
  1211 constructor terms) are part of the standard simpset;
  1212 
  1213   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1214 made part of standard simpset and claset via addIffs;
  1215 
  1216   3) a tactic for record field splitting (record_split_tac) is part of
  1217 the standard claset (addSWrapper);
  1218 
  1219 To get a better idea about these rules you may retrieve them via
  1220 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1221 the name of your record type.
  1222 
  1223 The split tactic 3) conceptually simplifies by the following rule:
  1224 
  1225   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1226 
  1227 Thus any record variable that is bound by meta-all will automatically
  1228 blow up into some record constructor term, consequently the
  1229 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1230 solve record problems automatically.
  1231 
  1232 
  1233 * reorganized the main HOL image: HOL/Integ and String loaded by
  1234 default; theory Main includes everything;
  1235 
  1236 * automatic simplification of integer sums and comparisons, using cancellation;
  1237 
  1238 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1239 
  1240 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1241 
  1242 * many new identities for unions, intersections, set difference, etc.;
  1243 
  1244 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1245 called split_if, split_split, split_sum_case and split_nat_case (to go
  1246 with add/delsplits);
  1247 
  1248 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1249 (?x::unit) = (); this is made part of the default simpset, which COULD
  1250 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1251 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1252 unit_abs_eta_conv is added in order to counter the effect of
  1253 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1254 %u.f();
  1255 
  1256 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1257 makes more sense);
  1258 
  1259 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1260   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1261   disjointness reasoning but breaking a few old proofs.
  1262 
  1263 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1264 to 'converse' from 'inverse' (for compatibility with ZF and some
  1265 literature);
  1266 
  1267 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1268 the well-founded relation;
  1269 
  1270 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1271     Compl A.  The "Compl" syntax remains available as input syntax for this
  1272     release ONLY.
  1273 
  1274 * HOL/Update: new theory of function updates:
  1275     f(a:=b) == %x. if x=a then b else f x
  1276 may also be iterated as in f(a:=b,c:=d,...);
  1277 
  1278 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1279 
  1280 * HOL/List:
  1281   - new function list_update written xs[i:=v] that updates the i-th
  1282     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1283   - new function `upt' written [i..j(] which generates the list
  1284     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1285     bound write [i..j], which is a shorthand for [i..j+1(].
  1286   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1287 
  1288 * HOL/Arith:
  1289   - removed 'pred' (predecessor) function;
  1290   - generalized some theorems about n-1;
  1291   - many new laws about "div" and "mod";
  1292   - new laws about greatest common divisors (see theory ex/Primes);
  1293 
  1294 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1295 instead of "inverse";
  1296 
  1297 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1298   of the multiset ordering;
  1299 
  1300 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1301   (not included by default);
  1302 
  1303 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1304 
  1305 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1306   programs, i.e. different program variables may have different types.
  1307 
  1308 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1309   [previously, this check worked only if the rewrite rule was unconditional]
  1310   Now rew can involve either definitions or equalities (either == or =).
  1311 
  1312 
  1313 *** ZF ***
  1314 
  1315 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1316   only the theorems proved on ZF.ML;
  1317 
  1318 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1319   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1320   disjointness reasoning but breaking a few old proofs.
  1321 
  1322 * ZF/Update: new theory of function updates
  1323     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1324   may also be iterated as in f(a:=b,c:=d,...);
  1325 
  1326 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1327 
  1328 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1329   [previously, this check worked only if the rewrite rule was unconditional]
  1330   Now rew can involve either definitions or equalities (either == or =).
  1331 
  1332 * case_tac provided for compatibility with HOL
  1333     (like the old excluded_middle_tac, but with subgoals swapped)
  1334 
  1335 
  1336 *** Internal programming interfaces ***
  1337 
  1338 * Pure: several new basic modules made available for general use, see
  1339 also src/Pure/README;
  1340 
  1341 * improved the theory data mechanism to support encapsulation (data
  1342 kind name replaced by private Object.kind, acting as authorization
  1343 key); new type-safe user interface via functor TheoryDataFun; generic
  1344 print_data function becomes basically useless;
  1345 
  1346 * removed global_names compatibility flag -- all theory declarations
  1347 are qualified by default;
  1348 
  1349 * module Pure/Syntax now offers quote / antiquote translation
  1350 functions (useful for Hoare logic etc. with implicit dependencies);
  1351 see HOL/ex/Antiquote for an example use;
  1352 
  1353 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1354 cterm -> thm;
  1355 
  1356 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1357 subgoal;
  1358 
  1359 * Display.print_goals function moved to Locale.print_goals;
  1360 
  1361 * standard print function for goals supports current_goals_markers
  1362 variable for marking begin of proof, end of proof, start of goal; the
  1363 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1364 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1365 for example;
  1366 
  1367 
  1368 
  1369 New in Isabelle98 (January 1998)
  1370 --------------------------------
  1371 
  1372 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1373 
  1374 * changed lexical syntax of terms / types: dots made part of long
  1375 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1376 
  1377 * simpset (and claset) reference variable replaced by functions
  1378 simpset / simpset_ref;
  1379 
  1380 * no longer supports theory aliases (via merge) and non-trivial
  1381 implicit merge of thms' signatures;
  1382 
  1383 * most internal names of constants changed due to qualified names;
  1384 
  1385 * changed Pure/Sequence interface (see Pure/seq.ML);
  1386 
  1387 
  1388 *** General Changes ***
  1389 
  1390 * hierachically structured name spaces (for consts, types, axms, thms
  1391 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1392 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1393 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1394 long_names for fully qualified output names; NOTE: ML programs
  1395 (special tactics, packages etc.) referring to internal names may have
  1396 to be adapted to cope with fully qualified names; in case of severe
  1397 backward campatibility problems try setting 'global_names' at compile
  1398 time to have enrything declared within a flat name space; one may also
  1399 fine tune name declarations in theories via the 'global' and 'local'
  1400 section;
  1401 
  1402 * reimplemented the implicit simpset and claset using the new anytype
  1403 data filed in signatures; references simpset:simpset ref etc. are
  1404 replaced by functions simpset:unit->simpset and
  1405 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1406 to patch your ML files accordingly;
  1407 
  1408 * HTML output now includes theory graph data for display with Java
  1409 applet or isatool browser; data generated automatically via isatool
  1410 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1411 
  1412 * defs may now be conditional; improved rewrite_goals_tac to handle
  1413 conditional equations;
  1414 
  1415 * defs now admits additional type arguments, using TYPE('a) syntax;
  1416 
  1417 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1418 creates a new theory node; implicit merge of thms' signatures is
  1419 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1420 transfer:theory->thm->thm in (rare) cases;
  1421 
  1422 * improved handling of draft signatures / theories; draft thms (and
  1423 ctyps, cterms) are automatically promoted to real ones;
  1424 
  1425 * slightly changed interfaces for oracles: admit many per theory, named
  1426 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1427 
  1428 * print_goals: optional output of const types (set show_consts and
  1429 show_types);
  1430 
  1431 * improved output of warnings (###) and errors (***);
  1432 
  1433 * subgoal_tac displays a warning if the new subgoal has type variables;
  1434 
  1435 * removed old README and Makefiles;
  1436 
  1437 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1438 
  1439 * removed obsolete init_pps and init_database;
  1440 
  1441 * deleted the obsolete tactical STATE, which was declared by
  1442     fun STATE tacfun st = tacfun st st;
  1443 
  1444 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1445 (which abbreviates $HOME);
  1446 
  1447 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1448 use isatool fixseq to adapt your ML programs (this works for fully
  1449 qualified references to the Sequence structure only!);
  1450 
  1451 * use_thy no longer requires writable current directory; it always
  1452 reloads .ML *and* .thy file, if either one is out of date;
  1453 
  1454 
  1455 *** Classical Reasoner ***
  1456 
  1457 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1458 tactics that use classical reasoning to simplify a subgoal without
  1459 splitting it into several subgoals;
  1460 
  1461 * Safe_tac: like safe_tac but uses the default claset;
  1462 
  1463 
  1464 *** Simplifier ***
  1465 
  1466 * added simplification meta rules:
  1467     (asm_)(full_)simplify: simpset -> thm -> thm;
  1468 
  1469 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1470 logics (again);
  1471 
  1472 * added prems argument to simplification procedures;
  1473 
  1474 * HOL, FOL, ZF: added infix function `addsplits':
  1475   instead of `<simpset> setloop (split_tac <thms>)'
  1476   you can simply write `<simpset> addsplits <thms>'
  1477 
  1478 
  1479 *** Syntax ***
  1480 
  1481 * TYPE('a) syntax for type reflection terms;
  1482 
  1483 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1484 
  1485 * pretty printer: changed order of mixfix annotation preference (again!);
  1486 
  1487 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1488 
  1489 
  1490 *** HOL ***
  1491 
  1492 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1493   with `addloop' of the simplifier to faciliate case splitting in premises.
  1494 
  1495 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1496 
  1497 * HOL/Auth: new protocol proofs including some for the Internet
  1498   protocol TLS;
  1499 
  1500 * HOL/Map: new theory of `maps' a la VDM;
  1501 
  1502 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1503 cancelling out common nat summands from =, <, <= (in)equalities, or
  1504 differences; simplification procedures nat_cancel_factor for
  1505 cancelling common factor from =, <, <= (in)equalities over natural
  1506 sums; nat_cancel contains both kinds of procedures, it is installed by
  1507 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1508 
  1509 * HOL/simplifier: terms of the form
  1510   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1511   are rewritten to
  1512   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1513   and those of the form
  1514   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1515   are rewritten to
  1516   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1517 
  1518 * HOL/datatype
  1519   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1520 
  1521   P(t_case f1 ... fn x) =
  1522      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1523         ...
  1524        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1525      )
  1526 
  1527   and a theorem `split_t_case_asm' of the form
  1528 
  1529   P(t_case f1 ... fn x) =
  1530     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1531         ...
  1532        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1533      )
  1534   which can be added to a simpset via `addsplits'. The existing theorems
  1535   expand_list_case and expand_option_case have been renamed to
  1536   split_list_case and split_option_case.
  1537 
  1538 * HOL/Arithmetic:
  1539   - `pred n' is automatically converted to `n-1'.
  1540     Users are strongly encouraged not to use `pred' any longer,
  1541     because it will disappear altogether at some point.
  1542   - Users are strongly encouraged to write "0 < n" rather than
  1543     "n ~= 0". Theorems and proof tools have been modified towards this
  1544     `standard'.
  1545 
  1546 * HOL/Lists:
  1547   the function "set_of_list" has been renamed "set" (and its theorems too);
  1548   the function "nth" now takes its arguments in the reverse order and
  1549   has acquired the infix notation "!" as in "xs!n".
  1550 
  1551 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1552 
  1553 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1554   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1555 
  1556 * HOL/record: extensible records with schematic structural subtyping
  1557 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1558 still lacks various theorems and concrete record syntax;
  1559 
  1560 
  1561 *** HOLCF ***
  1562 
  1563 * removed "axioms" and "generated by" sections;
  1564 
  1565 * replaced "ops" section by extended "consts" section, which is capable of
  1566   handling the continuous function space "->" directly;
  1567 
  1568 * domain package:
  1569   . proves theorems immediately and stores them in the theory,
  1570   . creates hierachical name space,
  1571   . now uses normal mixfix annotations (instead of cinfix...),
  1572   . minor changes to some names and values (for consistency),
  1573   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1574   . separator between mutual domain defs: changed "," to "and",
  1575   . improved handling of sort constraints;  now they have to
  1576     appear on the left-hand side of the equations only;
  1577 
  1578 * fixed LAM <x,y,zs>.b syntax;
  1579 
  1580 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1581 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1582 
  1583 
  1584 *** FOL and ZF ***
  1585 
  1586 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1587   with `addloop' of the simplifier to faciliate case splitting in premises.
  1588 
  1589 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1590 in HOL, they strip ALL and --> from proved theorems;
  1591 
  1592 
  1593 
  1594 New in Isabelle94-8 (May 1997)
  1595 ------------------------------
  1596 
  1597 *** General Changes ***
  1598 
  1599 * new utilities to build / run / maintain Isabelle etc. (in parts
  1600 still somewhat experimental); old Makefiles etc. still functional;
  1601 
  1602 * new 'Isabelle System Manual';
  1603 
  1604 * INSTALL text, together with ./configure and ./build scripts;
  1605 
  1606 * reimplemented type inference for greater efficiency, better error
  1607 messages and clean internal interface;
  1608 
  1609 * prlim command for dealing with lots of subgoals (an easier way of
  1610 setting goals_limit);
  1611 
  1612 
  1613 *** Syntax ***
  1614 
  1615 * supports alternative (named) syntax tables (parser and pretty
  1616 printer); internal interface is provided by add_modesyntax(_i);
  1617 
  1618 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1619 be used in conjunction with the Isabelle symbol font; uses the
  1620 "symbols" syntax table;
  1621 
  1622 * added token_translation interface (may translate name tokens in
  1623 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1624 the current print_mode); IMPORTANT: user print translation functions
  1625 are responsible for marking newly introduced bounds
  1626 (Syntax.mark_boundT);
  1627 
  1628 * token translations for modes "xterm" and "xterm_color" that display
  1629 names in bold, underline etc. or colors (which requires a color
  1630 version of xterm);
  1631 
  1632 * infixes may now be declared with names independent of their syntax;
  1633 
  1634 * added typed_print_translation (like print_translation, but may
  1635 access type of constant);
  1636 
  1637 
  1638 *** Classical Reasoner ***
  1639 
  1640 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1641 some limitations.  Blast_tac...
  1642   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1643   + ignores elimination rules that don't have the correct format
  1644         (the conclusion MUST be a formula variable)
  1645   + ignores types, which can make HOL proofs fail
  1646   + rules must not require higher-order unification, e.g. apply_type in ZF
  1647     [message "Function Var's argument not a bound variable" relates to this]
  1648   + its proof strategy is more general but can actually be slower
  1649 
  1650 * substitution with equality assumptions no longer permutes other
  1651 assumptions;
  1652 
  1653 * minor changes in semantics of addafter (now called addaltern); renamed
  1654 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1655 (and access functions for it);
  1656 
  1657 * improved combination of classical reasoner and simplifier:
  1658   + functions for handling clasimpsets
  1659   + improvement of addss: now the simplifier is called _after_ the
  1660     safe steps.
  1661   + safe variant of addss called addSss: uses safe simplifications
  1662     _during_ the safe steps. It is more complete as it allows multiple
  1663     instantiations of unknowns (e.g. with slow_tac).
  1664 
  1665 *** Simplifier ***
  1666 
  1667 * added interface for simplification procedures (functions that
  1668 produce *proven* rewrite rules on the fly, depending on current
  1669 redex);
  1670 
  1671 * ordering on terms as parameter (used for ordered rewriting);
  1672 
  1673 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1674 
  1675 * the solver is now split into a safe and an unsafe part.
  1676 This should be invisible for the normal user, except that the
  1677 functions setsolver and addsolver have been renamed to setSolver and
  1678 addSolver; added safe_asm_full_simp_tac;
  1679 
  1680 
  1681 *** HOL ***
  1682 
  1683 * a generic induction tactic `induct_tac' which works for all datatypes and
  1684 also for type `nat';
  1685 
  1686 * a generic case distinction tactic `exhaust_tac' which works for all
  1687 datatypes and also for type `nat';
  1688 
  1689 * each datatype comes with a function `size';
  1690 
  1691 * patterns in case expressions allow tuple patterns as arguments to
  1692 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1693 
  1694 * primrec now also works with type nat;
  1695 
  1696 * recdef: a new declaration form, allows general recursive functions to be
  1697 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1698 
  1699 * the constant for negation has been renamed from "not" to "Not" to
  1700 harmonize with FOL, ZF, LK, etc.;
  1701 
  1702 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1703 infinite lists;
  1704 
  1705 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1706 
  1707 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1708 problems in commutative rings, using axiomatic type classes for + and *;
  1709 
  1710 * more examples in HOL/MiniML and HOL/Auth;
  1711 
  1712 * more default rewrite rules for quantifiers, union/intersection;
  1713 
  1714 * a new constant `arbitrary == @x.False';
  1715 
  1716 * HOLCF/IOA replaces old HOL/IOA;
  1717 
  1718 * HOLCF changes: derived all rules and arities
  1719   + axiomatic type classes instead of classes
  1720   + typedef instead of faking type definitions
  1721   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1722   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1723   + eliminated the types void, one, tr
  1724   + use unit lift and bool lift (with translations) instead of one and tr
  1725   + eliminated blift from Lift3.thy (use Def instead of blift)
  1726   all eliminated rules are derived as theorems --> no visible changes ;
  1727 
  1728 
  1729 *** ZF ***
  1730 
  1731 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1732 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1733 as ZF_cs addSIs [equalityI];
  1734 
  1735 
  1736 
  1737 New in Isabelle94-7 (November 96)
  1738 ---------------------------------
  1739 
  1740 * allowing negative levels (as offsets) in prlev and choplev;
  1741 
  1742 * super-linear speedup for large simplifications;
  1743 
  1744 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1745 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1746 FAIL); can suppress it using the command Delsimps (ex_simps @
  1747 all_simps); De Morgan laws are also now included, by default;
  1748 
  1749 * improved printing of ==>  :  ~:
  1750 
  1751 * new object-logic "Sequents" adds linear logic, while replacing LK
  1752 and Modal (thanks to Sara Kalvala);
  1753 
  1754 * HOL/Auth: correctness proofs for authentication protocols;
  1755 
  1756 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1757 examples on HOL/Auth);
  1758 
  1759 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1760 the rewriter and classical reasoner simultaneously;
  1761 
  1762 * function uresult no longer returns theorems in "standard" format;
  1763 regain previous version by: val uresult = standard o uresult;
  1764 
  1765 
  1766 
  1767 New in Isabelle94-6
  1768 -------------------
  1769 
  1770 * oracles -- these establish an interface between Isabelle and trusted
  1771 external reasoners, which may deliver results as theorems;
  1772 
  1773 * proof objects (in particular record all uses of oracles);
  1774 
  1775 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1776 
  1777 * "constdefs" section in theory files;
  1778 
  1779 * "primrec" section (HOL) no longer requires names;
  1780 
  1781 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1782 
  1783 
  1784 
  1785 New in Isabelle94-5
  1786 -------------------
  1787 
  1788 * reduced space requirements;
  1789 
  1790 * automatic HTML generation from theories;
  1791 
  1792 * theory files no longer require "..." (quotes) around most types;
  1793 
  1794 * new examples, including two proofs of the Church-Rosser theorem;
  1795 
  1796 * non-curried (1994) version of HOL is no longer distributed;
  1797 
  1798 
  1799 
  1800 New in Isabelle94-4
  1801 -------------------
  1802 
  1803 * greatly reduced space requirements;
  1804 
  1805 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1806 
  1807 * searchable theorem database (see the section "Retrieving theorems" on
  1808 page 8 of the Reference Manual);
  1809 
  1810 * new examples, including Grabczewski's monumental case study of the
  1811 Axiom of Choice;
  1812 
  1813 * The previous version of HOL renamed to Old_HOL;
  1814 
  1815 * The new version of HOL (previously called CHOL) uses a curried syntax
  1816 for functions.  Application looks like f a b instead of f(a,b);
  1817 
  1818 * Mutually recursive inductive definitions finally work in HOL;
  1819 
  1820 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1821 translates to the operator "split";
  1822 
  1823 
  1824 
  1825 New in Isabelle94-3
  1826 -------------------
  1827 
  1828 * new infix operator, addss, allowing the classical reasoner to
  1829 perform simplification at each step of its search.  Example:
  1830         fast_tac (cs addss ss)
  1831 
  1832 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1833 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1834 look like (a,b) instead of <a,b>;
  1835 
  1836 * PLEASE NOTE: CHOL will eventually replace HOL!
  1837 
  1838 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1839 It translates to the operator "split".  A new theory of integers is available;
  1840 
  1841 * In ZF, integer numerals now denote two's-complement binary integers.
  1842 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1843 
  1844 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1845 of the Axiom of Choice;
  1846 
  1847 
  1848 
  1849 New in Isabelle94-2
  1850 -------------------
  1851 
  1852 * Significantly faster resolution;
  1853 
  1854 * the different sections in a .thy file can now be mixed and repeated
  1855 freely;
  1856 
  1857 * Database of theorems for FOL, HOL and ZF.  New
  1858 commands including qed, qed_goal and bind_thm store theorems in the database.
  1859 
  1860 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1861 a given theory (thms_of), or find out what theory a theorem was proved in
  1862 (theory_of_thm);
  1863 
  1864 * Bugs fixed in the inductive definition and datatype packages;
  1865 
  1866 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1867 and HOL_dup_cs obsolete;
  1868 
  1869 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1870 have been removed;
  1871 
  1872 * Simpler definition of function space in ZF;
  1873 
  1874 * new results about cardinal and ordinal arithmetic in ZF;
  1875 
  1876 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1877 types;
  1878 
  1879 
  1880 $Id$