NEWS
author paulson
Thu Nov 16 10:44:59 2000 +0100 (2000-11-16)
changeset 10474 25caae39bd7a
parent 10461 96529827ff71
child 10514 3db037155f0e
permissions -rw-r--r--
CTT
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 *** Overview of INCOMPATIBILITIES ***
     6 
     7 * HOL: induct renamed to lfp_induct;
     8 
     9 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
    10 
    11 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
    12 
    13 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
    14 consequence, it is no longer monotonic wrt. the local goal context
    15 (which is now passed through the inductive cases);
    16 
    17 
    18 *** Document preparation ***
    19 
    20 * improved isabelle style files; more abstract symbol implementation
    21 (should now use \isamath{...} and \isatext{...} in custom symbol
    22 definitions);
    23 
    24 * support sub/super scripts (for single symbols only), input syntax is
    25 like this: "A\<^sup>*" or "A\<^sup>\<star>";
    26 
    27 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals state;
    28 Note that presentation of goal states does not conform to actual
    29 human-readable proof documents.  Please do not include goal states
    30 into document output unless you really know what you are doing!
    31 
    32 
    33 *** Isar ***
    34 
    35 * Pure: assumption method (an implicit finishing) now handles actual
    36 rules as well;
    37 
    38 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
    39 initial goal, declare "that" only as Pure intro (only for single
    40 steps); the "that" rule assumption may now be involved in implicit
    41 finishing, thus ".." becomes a feasible for trivial obtains;
    42 
    43 * Pure: default proof step now includes 'intro_classes'; thus trivial
    44 instance proofs may be performed by "..";
    45 
    46 * Pure: ?thesis / ?this / "..." now work for pure meta-level
    47 statements as well;
    48 
    49 * HOL: improved method 'induct' --- now handles non-atomic goals
    50 (potential INCOMPATIBILITY); tuned error handling;
    51 
    52 
    53 *** HOL ***
    54 
    55 * HOL/Library: a collection of generic theories to be used together
    56 with main HOL; the theory loader path already includes this directory
    57 by default; the following existing theories have been moved here:
    58 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
    59 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
    60 
    61 * added overloaded operations "inverse" and "divide" (infix "/");
    62 
    63 * HOL/typedef: simplified package, provide more useful rules (see also
    64 HOL/subset.thy);
    65 
    66 
    67 *** CTT ***
    68 
    69 * CTT: x-symbol support for Pi, Sigma, -->, : (membership)
    70   note that "lam" is displayed as TWO lambda-symbols
    71 
    72 * CTT: theory Main now available, containing everything
    73 (that is, Bool and Arith) 
    74 
    75 *** General ***
    76 
    77 * Provers: fast_tac (and friends) now handle actual object-logic rules
    78 as assumptions as well;
    79 
    80 
    81 
    82 New in Isabelle99-1 (October 2000)
    83 ----------------------------------
    84 
    85 *** Overview of INCOMPATIBILITIES ***
    86 
    87 * HOL: simplification of natural numbers is much changed; to partly
    88 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
    89 issue the following ML commands:
    90 
    91   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
    92   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
    93 
    94 * HOL: simplification no longer dives into case-expressions; this is
    95 controlled by "t.weak_case_cong" for each datatype t;
    96 
    97 * HOL: nat_less_induct renamed to less_induct;
    98 
    99 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   100 fixsome to patch .thy and .ML sources automatically;
   101 
   102   select_equality  -> some_equality
   103   select_eq_Ex     -> some_eq_ex
   104   selectI2EX       -> someI2_ex
   105   selectI2         -> someI2
   106   selectI          -> someI
   107   select1_equality -> some1_equality
   108   Eps_sym_eq       -> some_sym_eq_trivial
   109   Eps_eq           -> some_eq_trivial
   110 
   111 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   112 
   113 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   114 instead);
   115 
   116 * HOL: the recursion equations generated by 'recdef' are now called
   117 f.simps instead of f.rules;
   118 
   119 * HOL: qed_spec_mp now also handles bounded ALL as well;
   120 
   121 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   122 sometimes be needed;
   123 
   124 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   125 
   126 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   127 
   128 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   129 product is now "<*>" instead of "Times"; the lexicographic product is
   130 now "<*lex*>" instead of "**";
   131 
   132 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   133 of main HOL, but was unused); better use HOL's datatype package;
   134 
   135 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   136 the old syntax may be recovered as follows:
   137 
   138   syntax (symbols)
   139     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   140       (infixl "\\<oplus>" 100)
   141 
   142 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   143 
   144 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   145 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   146 internally;
   147 
   148 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   149 changed from A/r to A//r;
   150 
   151 * ZF: new treatment of arithmetic (nat & int) may break some old
   152 proofs;
   153 
   154 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   155 rulify -> rule_format, elimify -> elim_format, ...);
   156 
   157 * Isar/Provers: intro/elim/dest attributes changed; renamed
   158 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   159 should have to change intro!! to intro? only); replaced "delrule" by
   160 "rule del";
   161 
   162 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   163 
   164 * Provers: strengthened force_tac by using new first_best_tac;
   165 
   166 * LaTeX document preparation: several changes of isabelle.sty (see
   167 lib/texinputs);
   168 
   169 
   170 *** Document preparation ***
   171 
   172 * formal comments (text blocks etc.) in new-style theories may now
   173 contain antiquotations of thm/prop/term/typ/text to be presented
   174 according to latex print mode; concrete syntax is like this:
   175 @{term[show_types] "f(x) = a + x"};
   176 
   177 * isatool mkdir provides easy setup of Isabelle session directories,
   178 including proper document sources;
   179 
   180 * generated LaTeX sources are now deleted after successful run
   181 (isatool document -c); may retain a copy somewhere else via -D option
   182 of isatool usedir;
   183 
   184 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   185 style files, achieving self-contained LaTeX sources and simplifying
   186 LaTeX debugging;
   187 
   188 * old-style theories now produce (crude) LaTeX output as well;
   189 
   190 * browser info session directories are now self-contained (may be put
   191 on WWW server seperately); improved graphs of nested sessions; removed
   192 graph for 'all sessions';
   193 
   194 * several improvements in isabelle style files; \isabellestyle{it}
   195 produces fake math mode output; \isamarkupheader is now \section by
   196 default; see lib/texinputs/isabelle.sty etc.;
   197 
   198 
   199 *** Isar ***
   200 
   201 * Isar/Pure: local results and corresponding term bindings are now
   202 subject to Hindley-Milner polymorphism (similar to ML); this
   203 accommodates incremental type-inference very nicely;
   204 
   205 * Isar/Pure: new derived language element 'obtain' supports
   206 generalized existence reasoning;
   207 
   208 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   209 support accumulation of results, without applying any rules yet;
   210 useful to collect intermediate results without explicit name
   211 references, and for use with transitivity rules with more than 2
   212 premises;
   213 
   214 * Isar/Pure: scalable support for case-analysis type proofs: new
   215 'case' language element refers to local contexts symbolically, as
   216 produced by certain proof methods; internally, case names are attached
   217 to theorems as "tags";
   218 
   219 * Isar/Pure: theory command 'hide' removes declarations from
   220 class/type/const name spaces;
   221 
   222 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   223 indicate potential overloading;
   224 
   225 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   226 
   227 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   228 "{a,b,c}" instead of {a,b,c};
   229 
   230 * Isar/Pure now provides its own version of intro/elim/dest
   231 attributes; useful for building new logics, but beware of confusion
   232 with the version in Provers/classical;
   233 
   234 * Isar/Pure: the local context of (non-atomic) goals is provided via
   235 case name 'antecedent';
   236 
   237 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   238 to the current context is now done automatically);
   239 
   240 * Isar/Pure: theory command 'method_setup' provides a simple interface
   241 for definining proof methods in ML;
   242 
   243 * Isar/Provers: intro/elim/dest attributes changed; renamed
   244 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   245 most cases, one should have to change intro!! to intro? only);
   246 replaced "delrule" by "rule del";
   247 
   248 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   249 'symmetric' attribute (the latter supercedes [RS sym]);
   250 
   251 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   252 method modifier); 'simp' method: 'only:' modifier removes loopers as
   253 well (including splits);
   254 
   255 * Isar/Provers: Simplifier and Classical methods now support all kind
   256 of modifiers used in the past, including 'cong', 'iff', etc.
   257 
   258 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   259 of Simplifier and Classical reasoner);
   260 
   261 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   262 now support named cases; major packages (inductive, datatype, primrec,
   263 recdef) support case names and properly name parameters;
   264 
   265 * Isar/HOL: new transitivity rules for substitution in inequalities --
   266 monotonicity conditions are extracted to be proven at end of
   267 calculations;
   268 
   269 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   270 method anyway;
   271 
   272 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   273 split_if split_if_asm; datatype package provides theorems foo.splits =
   274 foo.split foo.split_asm for each datatype;
   275 
   276 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   277 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   278 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   279 use "(cases (simplified))" method in proper proof texts);
   280 
   281 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   282 
   283 * Isar: names of theorems etc. may be natural numbers as well;
   284 
   285 * Isar: 'pr' command: optional arguments for goals_limit and
   286 ProofContext.prems_limit; no longer prints theory contexts, but only
   287 proof states;
   288 
   289 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   290 additional print modes to be specified; e.g. "pr(latex)" will print
   291 proof state according to the Isabelle LaTeX style;
   292 
   293 * Isar: improved support for emulating tactic scripts, including proof
   294 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   295 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   296 (for HOL datatypes);
   297 
   298 * Isar: simplified (more robust) goal selection of proof methods: 1st
   299 goal, all goals, or explicit goal specifier (tactic emulation); thus
   300 'proof method scripts' have to be in depth-first order;
   301 
   302 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   303 
   304 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   305 should instead use individual commands for printing items
   306 (print_commands, print_methods etc.);
   307 
   308 * Isar: added 'nothing' --- the empty list of theorems;
   309 
   310 
   311 *** HOL ***
   312 
   313 * HOL/MicroJava: formalization of a fragment of Java, together with a
   314 corresponding virtual machine and a specification of its bytecode
   315 verifier and a lightweight bytecode verifier, including proofs of
   316 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   317 Cornelia Pusch (see also the homepage of project Bali at
   318 http://isabelle.in.tum.de/Bali/);
   319 
   320 * HOL/Algebra: new theory of rings and univariate polynomials, by
   321 Clemens Ballarin;
   322 
   323 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   324 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   325 Rasmussen;
   326 
   327 * HOL/Lattice: fundamental concepts of lattice theory and order
   328 structures, including duals, properties of bounds versus algebraic
   329 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   330 Theorem for complete lattices etc.; may also serve as a demonstration
   331 for abstract algebraic reasoning using axiomatic type classes, and
   332 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   333 
   334 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   335 von Oheimb;
   336 
   337 * HOL/IMPP: extension of IMP with local variables and mutually
   338 recursive procedures, by David von Oheimb;
   339 
   340 * HOL/Lambda: converted into new-style theory and document;
   341 
   342 * HOL/ex/Multiquote: example of multiple nested quotations and
   343 anti-quotations -- basically a generalized version of de-Bruijn
   344 representation; very useful in avoiding lifting of operations;
   345 
   346 * HOL/record: added general record equality rule to simpset; fixed
   347 select-update simplification procedure to handle extended records as
   348 well; admit "r" as field name;
   349 
   350 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   351 other numeric types and also as the identity of groups, rings, etc.;
   352 
   353 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   354 Types nat and int belong to this axclass;
   355 
   356 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   357    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   358    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   359   two terms #m*u and #n*u are replaced by #(m+n)*u
   360     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   361   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   362     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   363 
   364 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   365 powerful prover for predicate logic but knows nothing of clasets; see
   366 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   367 
   368 * HOL: new version of "case_tac" subsumes both boolean case split and
   369 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   370 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   371 
   372 * HOL: simplification no longer dives into case-expressions: only the
   373 selector expression is simplified, but not the remaining arms; to
   374 enable full simplification of case-expressions for datatype t, you may
   375 remove t.weak_case_cong from the simpset, either globally (Delcongs
   376 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   377 
   378 * HOL/recdef: the recursion equations generated by 'recdef' for
   379 function 'f' are now called f.simps instead of f.rules; if all
   380 termination conditions are proved automatically, these simplification
   381 rules are added to the simpset, as in primrec; rules may be named
   382 individually as well, resulting in a separate list of theorems for
   383 each equation;
   384 
   385 * HOL/While is a new theory that provides a while-combinator. It
   386 permits the definition of tail-recursive functions without the
   387 provision of a termination measure. The latter is necessary once the
   388 invariant proof rule for while is applied.
   389 
   390 * HOL: new (overloaded) notation for the set of elements below/above
   391 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   392 
   393 * HOL: theorems impI, allI, ballI bound as "strip";
   394 
   395 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   396 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   397 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   398 
   399 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   400 
   401 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   402 main HOL, but was unused);
   403 
   404 * HOL: fewer consts declared as global (e.g. have to refer to
   405 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   406 
   407 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   408 in case of overlap with user translations (e.g. judgements over
   409 tuples); (note that the underlying logical represenation is still
   410 bogus);
   411 
   412 
   413 *** ZF ***
   414 
   415 * ZF: simplification automatically cancels common terms in arithmetic
   416 expressions over nat and int;
   417 
   418 * ZF: new treatment of nat to minimize type-checking: all operators
   419 coerce their operands to a natural number using the function natify,
   420 making the algebraic laws unconditional;
   421 
   422 * ZF: as above, for int: operators coerce their operands to an integer
   423 using the function intify;
   424 
   425 * ZF: the integer library now contains many of the usual laws for the
   426 orderings, including $<=, and monotonicity laws for $+ and $*;
   427 
   428 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   429 simplification;
   430 
   431 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   432 to the simplifier and classical reasoner simultaneously;
   433 
   434 
   435 *** General ***
   436 
   437 * Provers: blast_tac now handles actual object-logic rules as
   438 assumptions; note that auto_tac uses blast_tac internally as well;
   439 
   440 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   441 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   442 
   443 * Provers: delrules now handles destruct rules as well (no longer need
   444 explicit make_elim);
   445 
   446 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   447   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   448 use instead the strong form,
   449   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   450 in HOL, FOL and ZF the function cla_make_elim will create such rules
   451 from destruct-rules;
   452 
   453 * Provers: Simplifier.easy_setup provides a fast path to basic
   454 Simplifier setup for new object-logics;
   455 
   456 * Pure: AST translation rules no longer require constant head on LHS;
   457 
   458 * Pure: improved name spaces: ambiguous output is qualified; support
   459 for hiding of names;
   460 
   461 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   462 XSYMBOL_HOME; no longer need to do manual configuration in most
   463 situations;
   464 
   465 * system: compression of ML heaps images may now be controlled via -c
   466 option of isabelle and isatool usedir (currently only observed by
   467 Poly/ML);
   468 
   469 * system: isatool installfonts may handle X-Symbol fonts as well (very
   470 useful for remote X11);
   471 
   472 * system: provide TAGS file for Isabelle sources;
   473 
   474 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   475 order;
   476 
   477 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   478 timing flag supersedes proof_timing and Toplevel.trace;
   479 
   480 * ML: new combinators |>> and |>>> for incremental transformations
   481 with secondary results (e.g. certain theory extensions):
   482 
   483 * ML: PureThy.add_defs gets additional argument to indicate potential
   484 overloading (usually false);
   485 
   486 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   487 results;
   488 
   489 
   490 
   491 New in Isabelle99 (October 1999)
   492 --------------------------------
   493 
   494 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   495 
   496 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   497 are no longer simplified.  (This allows the simplifier to unfold recursive
   498 functional programs.)  To restore the old behaviour, declare
   499 
   500     Delcongs [if_weak_cong];
   501 
   502 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   503 complement;
   504 
   505 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   506 
   507 * HOL/datatype: mutual_induct_tac no longer exists --
   508   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   509 
   510 * HOL/typedef: fixed type inference for representing set; type
   511 arguments now have to occur explicitly on the rhs as type constraints;
   512 
   513 * ZF: The con_defs part of an inductive definition may no longer refer
   514 to constants declared in the same theory;
   515 
   516 * HOL, ZF: the function mk_cases, generated by the inductive
   517 definition package, has lost an argument.  To simplify its result, it
   518 uses the default simpset instead of a supplied list of theorems.
   519 
   520 * HOL/List: the constructors of type list are now Nil and Cons;
   521 
   522 * Simplifier: the type of the infix ML functions
   523         setSSolver addSSolver setSolver addSolver
   524 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   525 for packaging solvers. A solver is created via
   526         mk_solver: string -> (thm list -> int -> tactic) -> solver
   527 where the string argument is only a comment.
   528 
   529 
   530 *** Proof tools ***
   531 
   532 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   533 decision procedure for linear arithmetic. Currently it is used for
   534 types `nat', `int', and `real' in HOL (see below); it can, should and
   535 will be instantiated for other types and logics as well.
   536 
   537 * The simplifier now accepts rewrite rules with flexible heads, eg
   538      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   539   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   540   matching.
   541 
   542 
   543 *** General ***
   544 
   545 * New Isabelle/Isar subsystem provides an alternative to traditional
   546 tactical theorem proving; together with the ProofGeneral/isar user
   547 interface it offers an interactive environment for developing human
   548 readable proof documents (Isar == Intelligible semi-automated
   549 reasoning); for further information see isatool doc isar-ref,
   550 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   551 
   552 * improved and simplified presentation of theories: better HTML markup
   553 (including colors), graph views in several sizes; isatool usedir now
   554 provides a proper interface for user theories (via -P option); actual
   555 document preparation based on (PDF)LaTeX is available as well (for
   556 new-style theories only); see isatool doc system for more information;
   557 
   558 * native support for Proof General, both for classic Isabelle and
   559 Isabelle/Isar;
   560 
   561 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   562 using the graph browser tool;
   563 
   564 * Isabelle manuals now also available as PDF;
   565 
   566 * theory loader rewritten from scratch (may not be fully
   567 bug-compatible); old loadpath variable has been replaced by show_path,
   568 add_path, del_path, reset_path functions; new operations such as
   569 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   570 isatool doc ref);
   571 
   572 * improved isatool install: option -k creates KDE application icon,
   573 option -p DIR installs standalone binaries;
   574 
   575 * added ML_PLATFORM setting (useful for cross-platform installations);
   576 more robust handling of platform specific ML images for SML/NJ;
   577 
   578 * the settings environment is now statically scoped, i.e. it is never
   579 created again in sub-processes invoked from isabelle, isatool, or
   580 Isabelle;
   581 
   582 * path element specification '~~' refers to '$ISABELLE_HOME';
   583 
   584 * in locales, the "assumes" and "defines" parts may be omitted if
   585 empty;
   586 
   587 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   588 long arrows);
   589 
   590 * new print_mode "HTML";
   591 
   592 * new flag show_tags controls display of tags of theorems (which are
   593 basically just comments that may be attached by some tools);
   594 
   595 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   596 mode and goal output format:
   597 
   598 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   599 244c244
   600 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   601 ---
   602 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   603 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   604 181c181
   605 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   606 ---
   607 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   608 
   609 * function bind_thms stores lists of theorems (cf. bind_thm);
   610 
   611 * new shorthand tactics ftac, eatac, datac, fatac;
   612 
   613 * qed (and friends) now accept "" as result name; in that case the
   614 theorem is not stored, but proper checks and presentation of the
   615 result still apply;
   616 
   617 * theorem database now also indexes constants "Trueprop", "all",
   618 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   619 
   620 
   621 *** HOL ***
   622 
   623 ** HOL arithmetic **
   624 
   625 * There are now decision procedures for linear arithmetic over nat and
   626 int:
   627 
   628 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   629 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   630 are treated as atomic; subformulae not involving type `nat' or `int'
   631 are ignored; quantified subformulae are ignored unless they are
   632 positive universal or negative existential. The tactic has to be
   633 invoked by hand and can be a little bit slow. In particular, the
   634 running time is exponential in the number of occurrences of `min' and
   635 `max', and `-' on `nat'.
   636 
   637 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   638 (negated) (in)equalities among the premises and the conclusion into
   639 account (i.e. no compound formulae) and does not know about `min' and
   640 `max', and `-' on `nat'. It is fast and is used automatically by the
   641 simplifier.
   642 
   643 NB: At the moment, these decision procedures do not cope with mixed
   644 nat/int formulae where the two parts interact, such as `m < n ==>
   645 int(m) < int(n)'.
   646 
   647 * HOL/Numeral provides a generic theory of numerals (encoded
   648 efficiently as bit strings); setup for types nat/int/real is in place;
   649 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   650 int, existing theories and proof scripts may require a few additional
   651 type constraints;
   652 
   653 * integer division and remainder can now be performed on constant
   654 arguments;
   655 
   656 * many properties of integer multiplication, division and remainder
   657 are now available;
   658 
   659 * An interface to the Stanford Validity Checker (SVC) is available through the
   660 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   661 are proved automatically.  SVC must be installed separately, and its results
   662 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   663 invocation of the underlying oracle).  For SVC see
   664   http://verify.stanford.edu/SVC
   665 
   666 * IsaMakefile: the HOL-Real target now builds an actual image;
   667 
   668 
   669 ** HOL misc **
   670 
   671 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   672 (in Isabelle/Isar) -- by Gertrud Bauer;
   673 
   674 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   675 analysis for assembly languages with subtypes;
   676 
   677 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   678 -- avoids syntactic ambiguities and treats state, transition, and
   679 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   680 changed syntax and (many) tactics;
   681 
   682 * HOL/inductive: Now also handles more general introduction rules such
   683   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   684   theorems are now maintained within the theory (maintained via the
   685   "mono" attribute);
   686 
   687 * HOL/datatype: Now also handles arbitrarily branching datatypes
   688   (using function types) such as
   689 
   690   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   691 
   692 * HOL/record: record_simproc (part of the default simpset) takes care
   693 of selectors applied to updated records; record_split_tac is no longer
   694 part of the default claset; update_defs may now be removed from the
   695 simpset in many cases; COMPATIBILITY: old behavior achieved by
   696 
   697   claset_ref () := claset() addSWrapper record_split_wrapper;
   698   Delsimprocs [record_simproc]
   699 
   700 * HOL/typedef: fixed type inference for representing set; type
   701 arguments now have to occur explicitly on the rhs as type constraints;
   702 
   703 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   704 names rather than an ML expression;
   705 
   706 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   707 supplied later.  Program schemes can be defined, such as
   708     "While B C s = (if B s then While B C (C s) else s)"
   709 where the well-founded relation can be chosen after B and C have been given.
   710 
   711 * HOL/List: the constructors of type list are now Nil and Cons;
   712 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   713 course, ML tools referring to List.list.op # etc. have to be adapted;
   714 
   715 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   716 disabled by default; run isabelle with option -m HOL to get back to
   717 the original Gordon/HOL-style output;
   718 
   719 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   720 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   721 
   722 * HOL basic syntax simplified (more orthogonal): all variants of
   723 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   724 Eps operator is provided as well: "SOME x. P[x]";
   725 
   726 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   727 
   728 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   729 thus available for user theories;
   730 
   731 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   732 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   733 time;
   734 
   735 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   736 several times and then mp;
   737 
   738 
   739 *** LK ***
   740 
   741 * the notation <<...>> is now available as a notation for sequences of
   742 formulas;
   743 
   744 * the simplifier is now installed
   745 
   746 * the axiom system has been generalized (thanks to Soren Heilmann)
   747 
   748 * the classical reasoner now has a default rule database
   749 
   750 
   751 *** ZF ***
   752 
   753 * new primrec section allows primitive recursive functions to be given
   754 directly (as in HOL) over datatypes and the natural numbers;
   755 
   756 * new tactics induct_tac and exhaust_tac for induction (or case
   757 analysis) over datatypes and the natural numbers;
   758 
   759 * the datatype declaration of type T now defines the recursor T_rec;
   760 
   761 * simplification automatically does freeness reasoning for datatype
   762 constructors;
   763 
   764 * automatic type-inference, with AddTCs command to insert new
   765 type-checking rules;
   766 
   767 * datatype introduction rules are now added as Safe Introduction rules
   768 to the claset;
   769 
   770 * the syntax "if P then x else y" is now available in addition to
   771 if(P,x,y);
   772 
   773 
   774 *** Internal programming interfaces ***
   775 
   776 * tuned simplifier trace output; new flag debug_simp;
   777 
   778 * structures Vartab / Termtab (instances of TableFun) offer efficient
   779 tables indexed by indexname_ord / term_ord (compatible with aconv);
   780 
   781 * AxClass.axclass_tac lost the theory argument;
   782 
   783 * tuned current_goals_markers semantics: begin / end goal avoids
   784 printing empty lines;
   785 
   786 * removed prs and prs_fn hook, which was broken because it did not
   787 include \n in its semantics, forcing writeln to add one
   788 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   789 string -> unit if you really want to output text without newline;
   790 
   791 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   792 plain output, interface builders may have to enable 'isabelle_font'
   793 mode to get Isabelle font glyphs as before;
   794 
   795 * refined token_translation interface; INCOMPATIBILITY: output length
   796 now of type real instead of int;
   797 
   798 * theory loader actions may be traced via new ThyInfo.add_hook
   799 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   800 your own database of information attached to *whole* theories -- as
   801 opposed to intra-theory data slots offered via TheoryDataFun;
   802 
   803 * proper handling of dangling sort hypotheses (at last!);
   804 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   805 extra sort hypotheses that can be witnessed from the type signature;
   806 the force_strip_shyps flag is gone, any remaining shyps are simply
   807 left in the theorem (with a warning issued by strip_shyps_warning);
   808 
   809 
   810 
   811 New in Isabelle98-1 (October 1998)
   812 ----------------------------------
   813 
   814 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   815 
   816 * several changes of automated proof tools;
   817 
   818 * HOL: major changes to the inductive and datatype packages, including
   819 some minor incompatibilities of theory syntax;
   820 
   821 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   822 called `inj_on';
   823 
   824 * HOL: removed duplicate thms in Arith:
   825   less_imp_add_less  should be replaced by  trans_less_add1
   826   le_imp_add_le      should be replaced by  trans_le_add1
   827 
   828 * HOL: unary minus is now overloaded (new type constraints may be
   829 required);
   830 
   831 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   832 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   833 now taken as an integer constant.
   834 
   835 * Pure: ML function 'theory_of' renamed to 'theory';
   836 
   837 
   838 *** Proof tools ***
   839 
   840 * Simplifier:
   841   1. Asm_full_simp_tac is now more aggressive.
   842      1. It will sometimes reorient premises if that increases their power to
   843         simplify.
   844      2. It does no longer proceed strictly from left to right but may also
   845         rotate premises to achieve further simplification.
   846      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   847      old Asm_full_simp_tac in that it does not rotate premises.
   848   2. The simplifier now knows a little bit about nat-arithmetic.
   849 
   850 * Classical reasoner: wrapper mechanism for the classical reasoner now
   851 allows for selected deletion of wrappers, by introduction of names for
   852 wrapper functionals.  This implies that addbefore, addSbefore,
   853 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   854 and that adding two tactics with the same name overwrites the first
   855 one (emitting a warning).
   856   type wrapper = (int -> tactic) -> (int -> tactic)
   857   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   858   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   859   delWrapper, delSWrapper: claset *  string            -> claset
   860   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   861 
   862 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   863 semantics; addbefore now affects only the unsafe part of step_tac
   864 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   865 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   866 by Force_tac;
   867 
   868 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   869 compWrapper; added safe wrapper (and access functions for it);
   870 
   871 * HOL/split_all_tac is now much faster and fails if there is nothing
   872 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   873 and the names of the automatically generated variables have changed.
   874 split_all_tac has moved within claset() from unsafe wrappers to safe
   875 wrappers, which means that !!-bound variables are split much more
   876 aggressively, and safe_tac and clarify_tac now split such variables.
   877 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   878 Note: the same holds for record_split_tac, which does the job of
   879 split_all_tac for record fields.
   880 
   881 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   882 permanently to the default simpset using Addsplits just like
   883 Addsimps. They can be removed via Delsplits just like
   884 Delsimps. Lower-case versions are also available.
   885 
   886 * HOL/Simplifier: The rule split_if is now part of the default
   887 simpset. This means that the simplifier will eliminate all occurrences
   888 of if-then-else in the conclusion of a goal. To prevent this, you can
   889 either remove split_if completely from the default simpset by
   890 `Delsplits [split_if]' or remove it in a specific call of the
   891 simplifier using `... delsplits [split_if]'.  You can also add/delete
   892 other case splitting rules to/from the default simpset: every datatype
   893 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   894 t is the name of the datatype).
   895 
   896 * Classical reasoner / Simplifier combination: new force_tac (and
   897 derivatives Force_tac, force) combines rewriting and classical
   898 reasoning (and whatever other tools) similarly to auto_tac, but is
   899 aimed to solve the given subgoal completely.
   900 
   901 
   902 *** General ***
   903 
   904 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   905 and `goalw': the theory is no longer needed as an explicit argument -
   906 the current theory context is used; assumptions are no longer returned
   907 at the ML-level unless one of them starts with ==> or !!; it is
   908 recommended to convert to these new commands using isatool fixgoal
   909 (backup your sources first!);
   910 
   911 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   912 the current theory context, and 'theory' to lookup stored theories;
   913 
   914 * new theory section 'locale' for declaring constants, assumptions and
   915 definitions that have local scope;
   916 
   917 * new theory section 'nonterminals' for purely syntactic types;
   918 
   919 * new theory section 'setup' for generic ML setup functions
   920 (e.g. package initialization);
   921 
   922 * the distribution now includes Isabelle icons: see
   923 lib/logo/isabelle-{small,tiny}.xpm;
   924 
   925 * isatool install - install binaries with absolute references to
   926 ISABELLE_HOME/bin;
   927 
   928 * isatool logo -- create instances of the Isabelle logo (as EPS);
   929 
   930 * print mode 'emacs' reserved for Isamode;
   931 
   932 * support multiple print (ast) translations per constant name;
   933 
   934 * theorems involving oracles are now printed with a suffixed [!];
   935 
   936 
   937 *** HOL ***
   938 
   939 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   940 
   941 * HOL/inductive package reorganized and improved: now supports mutual
   942 definitions such as
   943 
   944   inductive EVEN ODD
   945     intrs
   946       null "0 : EVEN"
   947       oddI "n : EVEN ==> Suc n : ODD"
   948       evenI "n : ODD ==> Suc n : EVEN"
   949 
   950 new theorem list "elims" contains an elimination rule for each of the
   951 recursive sets; inductive definitions now handle disjunctive premises
   952 correctly (also ZF);
   953 
   954 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   955 "mutual_induct" no longer exists - the induction rule is always
   956 contained in "induct";
   957 
   958 
   959 * HOL/datatype package re-implemented and greatly improved: now
   960 supports mutually recursive datatypes such as
   961 
   962   datatype
   963     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   964             | SUM ('a aexp) ('a aexp)
   965             | DIFF ('a aexp) ('a aexp)
   966             | NUM 'a
   967   and
   968     'a bexp = LESS ('a aexp) ('a aexp)
   969             | AND ('a bexp) ('a bexp)
   970             | OR ('a bexp) ('a bexp)
   971 
   972 as well as indirectly recursive datatypes such as
   973 
   974   datatype
   975     ('a, 'b) term = Var 'a
   976                   | App 'b ((('a, 'b) term) list)
   977 
   978 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   979 induction on mutually / indirectly recursive datatypes.
   980 
   981 Primrec equations are now stored in theory and can be accessed via
   982 <function_name>.simps.
   983 
   984 INCOMPATIBILITIES:
   985 
   986   - Theories using datatypes must now have theory Datatype as an
   987     ancestor.
   988   - The specific <typename>.induct_tac no longer exists - use the
   989     generic induct_tac instead.
   990   - natE has been renamed to nat.exhaust - use exhaust_tac
   991     instead of res_inst_tac ... natE. Note that the variable
   992     names in nat.exhaust differ from the names in natE, this
   993     may cause some "fragile" proofs to fail.
   994   - The theorems split_<typename>_case and split_<typename>_case_asm
   995     have been renamed to <typename>.split and <typename>.split_asm.
   996   - Since default sorts of type variables are now handled correctly,
   997     some datatype definitions may have to be annotated with explicit
   998     sort constraints.
   999   - Primrec definitions no longer require function name and type
  1000     of recursive argument.
  1001 
  1002 Consider using isatool fixdatatype to adapt your theories and proof
  1003 scripts to the new package (backup your sources first!).
  1004 
  1005 
  1006 * HOL/record package: considerably improved implementation; now
  1007 includes concrete syntax for record types, terms, updates; theorems
  1008 for surjective pairing and splitting !!-bound record variables; proof
  1009 support is as follows:
  1010 
  1011   1) standard conversions (selectors or updates applied to record
  1012 constructor terms) are part of the standard simpset;
  1013 
  1014   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1015 made part of standard simpset and claset via addIffs;
  1016 
  1017   3) a tactic for record field splitting (record_split_tac) is part of
  1018 the standard claset (addSWrapper);
  1019 
  1020 To get a better idea about these rules you may retrieve them via
  1021 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1022 the name of your record type.
  1023 
  1024 The split tactic 3) conceptually simplifies by the following rule:
  1025 
  1026   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1027 
  1028 Thus any record variable that is bound by meta-all will automatically
  1029 blow up into some record constructor term, consequently the
  1030 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1031 solve record problems automatically.
  1032 
  1033 
  1034 * reorganized the main HOL image: HOL/Integ and String loaded by
  1035 default; theory Main includes everything;
  1036 
  1037 * automatic simplification of integer sums and comparisons, using cancellation;
  1038 
  1039 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1040 
  1041 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1042 
  1043 * many new identities for unions, intersections, set difference, etc.;
  1044 
  1045 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1046 called split_if, split_split, split_sum_case and split_nat_case (to go
  1047 with add/delsplits);
  1048 
  1049 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1050 (?x::unit) = (); this is made part of the default simpset, which COULD
  1051 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1052 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1053 unit_abs_eta_conv is added in order to counter the effect of
  1054 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1055 %u.f();
  1056 
  1057 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1058 makes more sense);
  1059 
  1060 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1061   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1062   disjointness reasoning but breaking a few old proofs.
  1063 
  1064 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1065 to 'converse' from 'inverse' (for compatibility with ZF and some
  1066 literature);
  1067 
  1068 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1069 the well-founded relation;
  1070 
  1071 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1072     Compl A.  The "Compl" syntax remains available as input syntax for this
  1073     release ONLY.
  1074 
  1075 * HOL/Update: new theory of function updates:
  1076     f(a:=b) == %x. if x=a then b else f x
  1077 may also be iterated as in f(a:=b,c:=d,...);
  1078 
  1079 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1080 
  1081 * HOL/List:
  1082   - new function list_update written xs[i:=v] that updates the i-th
  1083     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1084   - new function `upt' written [i..j(] which generates the list
  1085     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1086     bound write [i..j], which is a shorthand for [i..j+1(].
  1087   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1088 
  1089 * HOL/Arith:
  1090   - removed 'pred' (predecessor) function;
  1091   - generalized some theorems about n-1;
  1092   - many new laws about "div" and "mod";
  1093   - new laws about greatest common divisors (see theory ex/Primes);
  1094 
  1095 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1096 instead of "inverse";
  1097 
  1098 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1099   of the multiset ordering;
  1100 
  1101 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1102   (not included by default);
  1103 
  1104 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1105 
  1106 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1107   programs, i.e. different program variables may have different types.
  1108 
  1109 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1110   [previously, this check worked only if the rewrite rule was unconditional]
  1111   Now rew can involve either definitions or equalities (either == or =).
  1112 
  1113 
  1114 *** ZF ***
  1115 
  1116 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1117   only the theorems proved on ZF.ML;
  1118 
  1119 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1120   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1121   disjointness reasoning but breaking a few old proofs.
  1122 
  1123 * ZF/Update: new theory of function updates
  1124     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1125   may also be iterated as in f(a:=b,c:=d,...);
  1126 
  1127 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1128 
  1129 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1130   [previously, this check worked only if the rewrite rule was unconditional]
  1131   Now rew can involve either definitions or equalities (either == or =).
  1132 
  1133 * case_tac provided for compatibility with HOL
  1134     (like the old excluded_middle_tac, but with subgoals swapped)
  1135 
  1136 
  1137 *** Internal programming interfaces ***
  1138 
  1139 * Pure: several new basic modules made available for general use, see
  1140 also src/Pure/README;
  1141 
  1142 * improved the theory data mechanism to support encapsulation (data
  1143 kind name replaced by private Object.kind, acting as authorization
  1144 key); new type-safe user interface via functor TheoryDataFun; generic
  1145 print_data function becomes basically useless;
  1146 
  1147 * removed global_names compatibility flag -- all theory declarations
  1148 are qualified by default;
  1149 
  1150 * module Pure/Syntax now offers quote / antiquote translation
  1151 functions (useful for Hoare logic etc. with implicit dependencies);
  1152 see HOL/ex/Antiquote for an example use;
  1153 
  1154 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1155 cterm -> thm;
  1156 
  1157 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1158 subgoal;
  1159 
  1160 * Display.print_goals function moved to Locale.print_goals;
  1161 
  1162 * standard print function for goals supports current_goals_markers
  1163 variable for marking begin of proof, end of proof, start of goal; the
  1164 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1165 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1166 for example;
  1167 
  1168 
  1169 
  1170 New in Isabelle98 (January 1998)
  1171 --------------------------------
  1172 
  1173 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1174 
  1175 * changed lexical syntax of terms / types: dots made part of long
  1176 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1177 
  1178 * simpset (and claset) reference variable replaced by functions
  1179 simpset / simpset_ref;
  1180 
  1181 * no longer supports theory aliases (via merge) and non-trivial
  1182 implicit merge of thms' signatures;
  1183 
  1184 * most internal names of constants changed due to qualified names;
  1185 
  1186 * changed Pure/Sequence interface (see Pure/seq.ML);
  1187 
  1188 
  1189 *** General Changes ***
  1190 
  1191 * hierachically structured name spaces (for consts, types, axms, thms
  1192 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1193 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1194 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1195 long_names for fully qualified output names; NOTE: ML programs
  1196 (special tactics, packages etc.) referring to internal names may have
  1197 to be adapted to cope with fully qualified names; in case of severe
  1198 backward campatibility problems try setting 'global_names' at compile
  1199 time to have enrything declared within a flat name space; one may also
  1200 fine tune name declarations in theories via the 'global' and 'local'
  1201 section;
  1202 
  1203 * reimplemented the implicit simpset and claset using the new anytype
  1204 data filed in signatures; references simpset:simpset ref etc. are
  1205 replaced by functions simpset:unit->simpset and
  1206 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1207 to patch your ML files accordingly;
  1208 
  1209 * HTML output now includes theory graph data for display with Java
  1210 applet or isatool browser; data generated automatically via isatool
  1211 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1212 
  1213 * defs may now be conditional; improved rewrite_goals_tac to handle
  1214 conditional equations;
  1215 
  1216 * defs now admits additional type arguments, using TYPE('a) syntax;
  1217 
  1218 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1219 creates a new theory node; implicit merge of thms' signatures is
  1220 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1221 transfer:theory->thm->thm in (rare) cases;
  1222 
  1223 * improved handling of draft signatures / theories; draft thms (and
  1224 ctyps, cterms) are automatically promoted to real ones;
  1225 
  1226 * slightly changed interfaces for oracles: admit many per theory, named
  1227 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1228 
  1229 * print_goals: optional output of const types (set show_consts and
  1230 show_types);
  1231 
  1232 * improved output of warnings (###) and errors (***);
  1233 
  1234 * subgoal_tac displays a warning if the new subgoal has type variables;
  1235 
  1236 * removed old README and Makefiles;
  1237 
  1238 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1239 
  1240 * removed obsolete init_pps and init_database;
  1241 
  1242 * deleted the obsolete tactical STATE, which was declared by
  1243     fun STATE tacfun st = tacfun st st;
  1244 
  1245 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1246 (which abbreviates $HOME);
  1247 
  1248 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1249 use isatool fixseq to adapt your ML programs (this works for fully
  1250 qualified references to the Sequence structure only!);
  1251 
  1252 * use_thy no longer requires writable current directory; it always
  1253 reloads .ML *and* .thy file, if either one is out of date;
  1254 
  1255 
  1256 *** Classical Reasoner ***
  1257 
  1258 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1259 tactics that use classical reasoning to simplify a subgoal without
  1260 splitting it into several subgoals;
  1261 
  1262 * Safe_tac: like safe_tac but uses the default claset;
  1263 
  1264 
  1265 *** Simplifier ***
  1266 
  1267 * added simplification meta rules:
  1268     (asm_)(full_)simplify: simpset -> thm -> thm;
  1269 
  1270 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1271 logics (again);
  1272 
  1273 * added prems argument to simplification procedures;
  1274 
  1275 * HOL, FOL, ZF: added infix function `addsplits':
  1276   instead of `<simpset> setloop (split_tac <thms>)'
  1277   you can simply write `<simpset> addsplits <thms>'
  1278 
  1279 
  1280 *** Syntax ***
  1281 
  1282 * TYPE('a) syntax for type reflection terms;
  1283 
  1284 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1285 
  1286 * pretty printer: changed order of mixfix annotation preference (again!);
  1287 
  1288 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1289 
  1290 
  1291 *** HOL ***
  1292 
  1293 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1294   with `addloop' of the simplifier to faciliate case splitting in premises.
  1295 
  1296 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1297 
  1298 * HOL/Auth: new protocol proofs including some for the Internet
  1299   protocol TLS;
  1300 
  1301 * HOL/Map: new theory of `maps' a la VDM;
  1302 
  1303 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1304 cancelling out common nat summands from =, <, <= (in)equalities, or
  1305 differences; simplification procedures nat_cancel_factor for
  1306 cancelling common factor from =, <, <= (in)equalities over natural
  1307 sums; nat_cancel contains both kinds of procedures, it is installed by
  1308 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1309 
  1310 * HOL/simplifier: terms of the form
  1311   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1312   are rewritten to
  1313   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1314   and those of the form
  1315   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1316   are rewritten to
  1317   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1318 
  1319 * HOL/datatype
  1320   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1321 
  1322   P(t_case f1 ... fn x) =
  1323      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1324         ...
  1325        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1326      )
  1327 
  1328   and a theorem `split_t_case_asm' of the form
  1329 
  1330   P(t_case f1 ... fn x) =
  1331     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1332         ...
  1333        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1334      )
  1335   which can be added to a simpset via `addsplits'. The existing theorems
  1336   expand_list_case and expand_option_case have been renamed to
  1337   split_list_case and split_option_case.
  1338 
  1339 * HOL/Arithmetic:
  1340   - `pred n' is automatically converted to `n-1'.
  1341     Users are strongly encouraged not to use `pred' any longer,
  1342     because it will disappear altogether at some point.
  1343   - Users are strongly encouraged to write "0 < n" rather than
  1344     "n ~= 0". Theorems and proof tools have been modified towards this
  1345     `standard'.
  1346 
  1347 * HOL/Lists:
  1348   the function "set_of_list" has been renamed "set" (and its theorems too);
  1349   the function "nth" now takes its arguments in the reverse order and
  1350   has acquired the infix notation "!" as in "xs!n".
  1351 
  1352 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1353 
  1354 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1355   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1356 
  1357 * HOL/record: extensible records with schematic structural subtyping
  1358 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1359 still lacks various theorems and concrete record syntax;
  1360 
  1361 
  1362 *** HOLCF ***
  1363 
  1364 * removed "axioms" and "generated by" sections;
  1365 
  1366 * replaced "ops" section by extended "consts" section, which is capable of
  1367   handling the continuous function space "->" directly;
  1368 
  1369 * domain package:
  1370   . proves theorems immediately and stores them in the theory,
  1371   . creates hierachical name space,
  1372   . now uses normal mixfix annotations (instead of cinfix...),
  1373   . minor changes to some names and values (for consistency),
  1374   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1375   . separator between mutual domain defs: changed "," to "and",
  1376   . improved handling of sort constraints;  now they have to
  1377     appear on the left-hand side of the equations only;
  1378 
  1379 * fixed LAM <x,y,zs>.b syntax;
  1380 
  1381 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1382 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1383 
  1384 
  1385 *** FOL and ZF ***
  1386 
  1387 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1388   with `addloop' of the simplifier to faciliate case splitting in premises.
  1389 
  1390 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1391 in HOL, they strip ALL and --> from proved theorems;
  1392 
  1393 
  1394 
  1395 New in Isabelle94-8 (May 1997)
  1396 ------------------------------
  1397 
  1398 *** General Changes ***
  1399 
  1400 * new utilities to build / run / maintain Isabelle etc. (in parts
  1401 still somewhat experimental); old Makefiles etc. still functional;
  1402 
  1403 * new 'Isabelle System Manual';
  1404 
  1405 * INSTALL text, together with ./configure and ./build scripts;
  1406 
  1407 * reimplemented type inference for greater efficiency, better error
  1408 messages and clean internal interface;
  1409 
  1410 * prlim command for dealing with lots of subgoals (an easier way of
  1411 setting goals_limit);
  1412 
  1413 
  1414 *** Syntax ***
  1415 
  1416 * supports alternative (named) syntax tables (parser and pretty
  1417 printer); internal interface is provided by add_modesyntax(_i);
  1418 
  1419 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1420 be used in conjunction with the Isabelle symbol font; uses the
  1421 "symbols" syntax table;
  1422 
  1423 * added token_translation interface (may translate name tokens in
  1424 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1425 the current print_mode); IMPORTANT: user print translation functions
  1426 are responsible for marking newly introduced bounds
  1427 (Syntax.mark_boundT);
  1428 
  1429 * token translations for modes "xterm" and "xterm_color" that display
  1430 names in bold, underline etc. or colors (which requires a color
  1431 version of xterm);
  1432 
  1433 * infixes may now be declared with names independent of their syntax;
  1434 
  1435 * added typed_print_translation (like print_translation, but may
  1436 access type of constant);
  1437 
  1438 
  1439 *** Classical Reasoner ***
  1440 
  1441 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1442 some limitations.  Blast_tac...
  1443   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1444   + ignores elimination rules that don't have the correct format
  1445         (the conclusion MUST be a formula variable)
  1446   + ignores types, which can make HOL proofs fail
  1447   + rules must not require higher-order unification, e.g. apply_type in ZF
  1448     [message "Function Var's argument not a bound variable" relates to this]
  1449   + its proof strategy is more general but can actually be slower
  1450 
  1451 * substitution with equality assumptions no longer permutes other
  1452 assumptions;
  1453 
  1454 * minor changes in semantics of addafter (now called addaltern); renamed
  1455 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1456 (and access functions for it);
  1457 
  1458 * improved combination of classical reasoner and simplifier:
  1459   + functions for handling clasimpsets
  1460   + improvement of addss: now the simplifier is called _after_ the
  1461     safe steps.
  1462   + safe variant of addss called addSss: uses safe simplifications
  1463     _during_ the safe steps. It is more complete as it allows multiple
  1464     instantiations of unknowns (e.g. with slow_tac).
  1465 
  1466 *** Simplifier ***
  1467 
  1468 * added interface for simplification procedures (functions that
  1469 produce *proven* rewrite rules on the fly, depending on current
  1470 redex);
  1471 
  1472 * ordering on terms as parameter (used for ordered rewriting);
  1473 
  1474 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1475 
  1476 * the solver is now split into a safe and an unsafe part.
  1477 This should be invisible for the normal user, except that the
  1478 functions setsolver and addsolver have been renamed to setSolver and
  1479 addSolver; added safe_asm_full_simp_tac;
  1480 
  1481 
  1482 *** HOL ***
  1483 
  1484 * a generic induction tactic `induct_tac' which works for all datatypes and
  1485 also for type `nat';
  1486 
  1487 * a generic case distinction tactic `exhaust_tac' which works for all
  1488 datatypes and also for type `nat';
  1489 
  1490 * each datatype comes with a function `size';
  1491 
  1492 * patterns in case expressions allow tuple patterns as arguments to
  1493 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1494 
  1495 * primrec now also works with type nat;
  1496 
  1497 * recdef: a new declaration form, allows general recursive functions to be
  1498 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1499 
  1500 * the constant for negation has been renamed from "not" to "Not" to
  1501 harmonize with FOL, ZF, LK, etc.;
  1502 
  1503 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1504 infinite lists;
  1505 
  1506 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1507 
  1508 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1509 problems in commutative rings, using axiomatic type classes for + and *;
  1510 
  1511 * more examples in HOL/MiniML and HOL/Auth;
  1512 
  1513 * more default rewrite rules for quantifiers, union/intersection;
  1514 
  1515 * a new constant `arbitrary == @x.False';
  1516 
  1517 * HOLCF/IOA replaces old HOL/IOA;
  1518 
  1519 * HOLCF changes: derived all rules and arities
  1520   + axiomatic type classes instead of classes
  1521   + typedef instead of faking type definitions
  1522   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1523   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1524   + eliminated the types void, one, tr
  1525   + use unit lift and bool lift (with translations) instead of one and tr
  1526   + eliminated blift from Lift3.thy (use Def instead of blift)
  1527   all eliminated rules are derived as theorems --> no visible changes ;
  1528 
  1529 
  1530 *** ZF ***
  1531 
  1532 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1533 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1534 as ZF_cs addSIs [equalityI];
  1535 
  1536 
  1537 
  1538 New in Isabelle94-7 (November 96)
  1539 ---------------------------------
  1540 
  1541 * allowing negative levels (as offsets) in prlev and choplev;
  1542 
  1543 * super-linear speedup for large simplifications;
  1544 
  1545 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1546 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1547 FAIL); can suppress it using the command Delsimps (ex_simps @
  1548 all_simps); De Morgan laws are also now included, by default;
  1549 
  1550 * improved printing of ==>  :  ~:
  1551 
  1552 * new object-logic "Sequents" adds linear logic, while replacing LK
  1553 and Modal (thanks to Sara Kalvala);
  1554 
  1555 * HOL/Auth: correctness proofs for authentication protocols;
  1556 
  1557 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1558 examples on HOL/Auth);
  1559 
  1560 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1561 the rewriter and classical reasoner simultaneously;
  1562 
  1563 * function uresult no longer returns theorems in "standard" format;
  1564 regain previous version by: val uresult = standard o uresult;
  1565 
  1566 
  1567 
  1568 New in Isabelle94-6
  1569 -------------------
  1570 
  1571 * oracles -- these establish an interface between Isabelle and trusted
  1572 external reasoners, which may deliver results as theorems;
  1573 
  1574 * proof objects (in particular record all uses of oracles);
  1575 
  1576 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1577 
  1578 * "constdefs" section in theory files;
  1579 
  1580 * "primrec" section (HOL) no longer requires names;
  1581 
  1582 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1583 
  1584 
  1585 
  1586 New in Isabelle94-5
  1587 -------------------
  1588 
  1589 * reduced space requirements;
  1590 
  1591 * automatic HTML generation from theories;
  1592 
  1593 * theory files no longer require "..." (quotes) around most types;
  1594 
  1595 * new examples, including two proofs of the Church-Rosser theorem;
  1596 
  1597 * non-curried (1994) version of HOL is no longer distributed;
  1598 
  1599 
  1600 
  1601 New in Isabelle94-4
  1602 -------------------
  1603 
  1604 * greatly reduced space requirements;
  1605 
  1606 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1607 
  1608 * searchable theorem database (see the section "Retrieving theorems" on
  1609 page 8 of the Reference Manual);
  1610 
  1611 * new examples, including Grabczewski's monumental case study of the
  1612 Axiom of Choice;
  1613 
  1614 * The previous version of HOL renamed to Old_HOL;
  1615 
  1616 * The new version of HOL (previously called CHOL) uses a curried syntax
  1617 for functions.  Application looks like f a b instead of f(a,b);
  1618 
  1619 * Mutually recursive inductive definitions finally work in HOL;
  1620 
  1621 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1622 translates to the operator "split";
  1623 
  1624 
  1625 
  1626 New in Isabelle94-3
  1627 -------------------
  1628 
  1629 * new infix operator, addss, allowing the classical reasoner to
  1630 perform simplification at each step of its search.  Example:
  1631         fast_tac (cs addss ss)
  1632 
  1633 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1634 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1635 look like (a,b) instead of <a,b>;
  1636 
  1637 * PLEASE NOTE: CHOL will eventually replace HOL!
  1638 
  1639 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1640 It translates to the operator "split".  A new theory of integers is available;
  1641 
  1642 * In ZF, integer numerals now denote two's-complement binary integers.
  1643 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1644 
  1645 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1646 of the Axiom of Choice;
  1647 
  1648 
  1649 
  1650 New in Isabelle94-2
  1651 -------------------
  1652 
  1653 * Significantly faster resolution;
  1654 
  1655 * the different sections in a .thy file can now be mixed and repeated
  1656 freely;
  1657 
  1658 * Database of theorems for FOL, HOL and ZF.  New
  1659 commands including qed, qed_goal and bind_thm store theorems in the database.
  1660 
  1661 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1662 a given theory (thms_of), or find out what theory a theorem was proved in
  1663 (theory_of_thm);
  1664 
  1665 * Bugs fixed in the inductive definition and datatype packages;
  1666 
  1667 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1668 and HOL_dup_cs obsolete;
  1669 
  1670 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1671 have been removed;
  1672 
  1673 * Simpler definition of function space in ZF;
  1674 
  1675 * new results about cardinal and ordinal arithmetic in ZF;
  1676 
  1677 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1678 types;
  1679 
  1680 
  1681 $Id$