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NEWS

author | nipkow |

Mon Oct 16 10:59:35 2000 +0200 (2000-10-16) | |

changeset 10224 | 7263c856787e |

parent 10164 | c240747082aa |

child 10245 | 87771e2f49fe |

permissions | -rw-r--r-- |

*** empty log message ***

1 Isabelle NEWS -- history user-relevant changes

2 ==============================================

4 *** Overview of INCOMPATIBILITIES ***

6 * HOL: induct renamed to lfp_induct;

9 New in Isabelle99-1 (October 2000)

10 ----------------------------------

12 *** Overview of INCOMPATIBILITIES ***

14 * HOL: simplification of natural numbers is much changed; to partly

15 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)

16 issue the following ML commands:

18 Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;

19 Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];

21 * HOL: simplification no longer dives into case-expressions; this is

22 controlled by "t.weak_case_cong" for each datatype t;

24 * HOL: nat_less_induct renamed to less_induct;

26 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool

27 fixsome to patch .thy and .ML sources automatically;

29 select_equality -> some_equality

30 select_eq_Ex -> some_eq_ex

31 selectI2EX -> someI2_ex

32 selectI2 -> someI2

33 selectI -> someI

34 select1_equality -> some1_equality

35 Eps_sym_eq -> some_sym_eq_trivial

36 Eps_eq -> some_eq_trivial

38 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;

40 * HOL: removed obsolete theorem binding expand_if (refer to split_if

41 instead);

43 * HOL: the recursion equations generated by 'recdef' are now called

44 f.simps instead of f.rules;

46 * HOL: qed_spec_mp now also handles bounded ALL as well;

48 * HOL: 0 is now overloaded, so the type constraint ":: nat" may

49 sometimes be needed;

51 * HOL: the constant for "f``x" is now "image" rather than "op ``";

53 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";

55 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian

56 product is now "<*>" instead of "Times"; the lexicographic product is

57 now "<*lex*>" instead of "**";

59 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part

60 of main HOL, but was unused); better use HOL's datatype package;

62 * HOL: removed "symbols" syntax for constant "override" of theory Map;

63 the old syntax may be recovered as follows:

65 syntax (symbols)

66 override :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"

67 (infixl "\\<oplus>" 100)

69 * HOL/Real: "rabs" replaced by overloaded "abs" function;

71 * HOL/ML: even fewer consts are declared as global (see theories Ord,

72 Lfp, Gfp, WF); this only affects ML packages that refer to const names

73 internally;

75 * HOL and ZF: syntax for quotienting wrt an equivalence relation

76 changed from A/r to A//r;

78 * ZF: new treatment of arithmetic (nat & int) may break some old

79 proofs;

81 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,

82 rulify -> rule_format, elimify -> elim_format, ...);

84 * Isar/Provers: intro/elim/dest attributes changed; renamed

85 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one

86 should have to change intro!! to intro? only); replaced "delrule" by

87 "rule del";

89 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;

91 * Provers: strengthened force_tac by using new first_best_tac;

93 * LaTeX document preparation: several changes of isabelle.sty (see

94 lib/texinputs);

97 *** Document preparation ***

99 * formal comments (text blocks etc.) in new-style theories may now

100 contain antiquotations of thm/prop/term/typ/text to be presented

101 according to latex print mode; concrete syntax is like this:

102 @{term[show_types] "f(x) = a + x"};

104 * isatool mkdir provides easy setup of Isabelle session directories,

105 including proper document sources;

107 * generated LaTeX sources are now deleted after successful run

108 (isatool document -c); may retain a copy somewhere else via -D option

109 of isatool usedir;

111 * isatool usedir -D now lets isatool latex -o sty update the Isabelle

112 style files, achieving self-contained LaTeX sources and simplifying

113 LaTeX debugging;

115 * old-style theories now produce (crude) LaTeX output as well;

117 * browser info session directories are now self-contained (may be put

118 on WWW server seperately); improved graphs of nested sessions; removed

119 graph for 'all sessions';

121 * several improvements in isabelle style files; \isabellestyle{it}

122 produces fake math mode output; \isamarkupheader is now \section by

123 default; see lib/texinputs/isabelle.sty etc.;

126 *** Isar ***

128 * Isar/Pure: local results and corresponding term bindings are now

129 subject to Hindley-Milner polymorphism (similar to ML); this

130 accommodates incremental type-inference very nicely;

132 * Isar/Pure: new derived language element 'obtain' supports

133 generalized existence reasoning;

135 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'

136 support accumulation of results, without applying any rules yet;

137 useful to collect intermediate results without explicit name

138 references, and for use with transitivity rules with more than 2

139 premises;

141 * Isar/Pure: scalable support for case-analysis type proofs: new

142 'case' language element refers to local contexts symbolically, as

143 produced by certain proof methods; internally, case names are attached

144 to theorems as "tags";

146 * Isar/Pure: theory command 'hide' removes declarations from

147 class/type/const name spaces;

149 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to

150 indicate potential overloading;

152 * Isar/Pure: changed syntax of local blocks from {{ }} to { };

154 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write

155 "{a,b,c}" instead of {a,b,c};

157 * Isar/Pure now provides its own version of intro/elim/dest

158 attributes; useful for building new logics, but beware of confusion

159 with the version in Provers/classical;

161 * Isar/Pure: the local context of (non-atomic) goals is provided via

162 case name 'antecedent';

164 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms

165 to the current context is now done automatically);

167 * Isar/Pure: theory command 'method_setup' provides a simple interface

168 for definining proof methods in ML;

170 * Isar/Provers: intro/elim/dest attributes changed; renamed

171 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in

172 most cases, one should have to change intro!! to intro? only);

173 replaced "delrule" by "rule del";

175 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and

176 'symmetric' attribute (the latter supercedes [RS sym]);

178 * Isar/Provers: splitter support (via 'split' attribute and 'simp'

179 method modifier); 'simp' method: 'only:' modifier removes loopers as

180 well (including splits);

182 * Isar/Provers: Simplifier and Classical methods now support all kind

183 of modifiers used in the past, including 'cong', 'iff', etc.

185 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination

186 of Simplifier and Classical reasoner);

188 * Isar/HOL: new proof method 'cases' and improved version of 'induct'

189 now support named cases; major packages (inductive, datatype, primrec,

190 recdef) support case names and properly name parameters;

192 * Isar/HOL: new transitivity rules for substitution in inequalities --

193 monotonicity conditions are extracted to be proven at end of

194 calculations;

196 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof

197 method anyway;

199 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =

200 split_if split_if_asm; datatype package provides theorems foo.splits =

201 foo.split foo.split_asm for each datatype;

203 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"

204 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof

205 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:

206 use "(cases (simplified))" method in proper proof texts);

208 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;

210 * Isar: names of theorems etc. may be natural numbers as well;

212 * Isar: 'pr' command: optional arguments for goals_limit and

213 ProofContext.prems_limit; no longer prints theory contexts, but only

214 proof states;

216 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit

217 additional print modes to be specified; e.g. "pr(latex)" will print

218 proof state according to the Isabelle LaTeX style;

220 * Isar: improved support for emulating tactic scripts, including proof

221 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',

222 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'

223 (for HOL datatypes);

225 * Isar: simplified (more robust) goal selection of proof methods: 1st

226 goal, all goals, or explicit goal specifier (tactic emulation); thus

227 'proof method scripts' have to be in depth-first order;

229 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';

231 * Isar: removed 'help' command, which hasn't been too helpful anyway;

232 should instead use individual commands for printing items

233 (print_commands, print_methods etc.);

235 * Isar: added 'nothing' --- the empty list of theorems;

238 *** HOL ***

240 * HOL/MicroJava: formalization of a fragment of Java, together with a

241 corresponding virtual machine and a specification of its bytecode

242 verifier and a lightweight bytecode verifier, including proofs of

243 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and

244 Cornelia Pusch (see also the homepage of project Bali at

245 http://isabelle.in.tum.de/Bali/);

247 * HOL/Algebra: new theory of rings and univariate polynomials, by

248 Clemens Ballarin;

250 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese

251 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M

252 Rasmussen;

254 * HOL/Lattice: fundamental concepts of lattice theory and order

255 structures, including duals, properties of bounds versus algebraic

256 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski

257 Theorem for complete lattices etc.; may also serve as a demonstration

258 for abstract algebraic reasoning using axiomatic type classes, and

259 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;

261 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David

262 von Oheimb;

264 * HOL/IMPP: extension of IMP with local variables and mutually

265 recursive procedures, by David von Oheimb;

267 * HOL/Lambda: converted into new-style theory and document;

269 * HOL/ex/Multiquote: example of multiple nested quotations and

270 anti-quotations -- basically a generalized version of de-Bruijn

271 representation; very useful in avoiding lifting of operations;

273 * HOL/record: added general record equality rule to simpset; fixed

274 select-update simplification procedure to handle extended records as

275 well; admit "r" as field name;

277 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with

278 other numeric types and also as the identity of groups, rings, etc.;

280 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.

281 Types nat and int belong to this axclass;

283 * HOL: greatly improved simplification involving numerals of type nat, int, real:

284 (i + #8 + j) = Suc k simplifies to #7 + (i + j) = k

285 i*j + k + j*#3*i simplifies to #4*(i*j) + k

286 two terms #m*u and #n*u are replaced by #(m+n)*u

287 (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)

288 and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y

289 or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);

291 * HOL: meson_tac is available (previously in ex/meson.ML); it is a

292 powerful prover for predicate logic but knows nothing of clasets; see

293 ex/mesontest.ML and ex/mesontest2.ML for example applications;

295 * HOL: new version of "case_tac" subsumes both boolean case split and

296 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer

297 exists, may define val exhaust_tac = case_tac for ad-hoc portability;

299 * HOL: simplification no longer dives into case-expressions: only the

300 selector expression is simplified, but not the remaining arms; to

301 enable full simplification of case-expressions for datatype t, you may

302 remove t.weak_case_cong from the simpset, either globally (Delcongs

303 [thm"t.weak_case_cong"];) or locally (delcongs [...]).

305 * HOL/recdef: the recursion equations generated by 'recdef' for

306 function 'f' are now called f.simps instead of f.rules; if all

307 termination conditions are proved automatically, these simplification

308 rules are added to the simpset, as in primrec; rules may be named

309 individually as well, resulting in a separate list of theorems for

310 each equation;

312 * HOL/While is a new theory that provides a while-combinator. It

313 permits the definition of tail-recursive functions without the

314 provision of a termination measure. The latter is necessary once the

315 invariant proof rule for while is applied.

317 * HOL: new (overloaded) notation for the set of elements below/above

318 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.

320 * HOL: theorems impI, allI, ballI bound as "strip";

322 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic

323 induct_tac th "x1 ... xn" expects th to have a conclusion of the form

324 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;

326 * HOL/Real: "rabs" replaced by overloaded "abs" function;

328 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of

329 main HOL, but was unused);

331 * HOL: fewer consts declared as global (e.g. have to refer to

332 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);

334 * HOL: tuned AST representation of nested pairs, avoiding bogus output

335 in case of overlap with user translations (e.g. judgements over

336 tuples); (note that the underlying logical represenation is still

337 bogus);

340 *** ZF ***

342 * ZF: simplification automatically cancels common terms in arithmetic

343 expressions over nat and int;

345 * ZF: new treatment of nat to minimize type-checking: all operators

346 coerce their operands to a natural number using the function natify,

347 making the algebraic laws unconditional;

349 * ZF: as above, for int: operators coerce their operands to an integer

350 using the function intify;

352 * ZF: the integer library now contains many of the usual laws for the

353 orderings, including $<=, and monotonicity laws for $+ and $*;

355 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic

356 simplification;

358 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q

359 to the simplifier and classical reasoner simultaneously;

362 *** General ***

364 * Provers: blast_tac now handles actual object-logic rules as

365 assumptions; note that auto_tac uses blast_tac internally as well;

367 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning

368 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;

370 * Provers: delrules now handles destruct rules as well (no longer need

371 explicit make_elim);

373 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.

374 [| inj ?f; ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W

375 use instead the strong form,

376 [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W

377 in HOL, FOL and ZF the function cla_make_elim will create such rules

378 from destruct-rules;

380 * Provers: Simplifier.easy_setup provides a fast path to basic

381 Simplifier setup for new object-logics;

383 * Pure: AST translation rules no longer require constant head on LHS;

385 * Pure: improved name spaces: ambiguous output is qualified; support

386 for hiding of names;

388 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and

389 XSYMBOL_HOME; no longer need to do manual configuration in most

390 situations;

392 * system: compression of ML heaps images may now be controlled via -c

393 option of isabelle and isatool usedir (currently only observed by

394 Poly/ML);

396 * system: isatool installfonts may handle X-Symbol fonts as well (very

397 useful for remote X11);

399 * system: provide TAGS file for Isabelle sources;

401 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument

402 order;

404 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global

405 timing flag supersedes proof_timing and Toplevel.trace;

407 * ML: new combinators |>> and |>>> for incremental transformations

408 with secondary results (e.g. certain theory extensions):

410 * ML: PureThy.add_defs gets additional argument to indicate potential

411 overloading (usually false);

413 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as

414 results;

418 New in Isabelle99 (October 1999)

419 --------------------------------

421 *** Overview of INCOMPATIBILITIES (see below for more details) ***

423 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)

424 are no longer simplified. (This allows the simplifier to unfold recursive

425 functional programs.) To restore the old behaviour, declare

427 Delcongs [if_weak_cong];

429 * HOL: Removed the obsolete syntax "Compl A"; use -A for set

430 complement;

432 * HOL: the predicate "inj" is now defined by translation to "inj_on";

434 * HOL/datatype: mutual_induct_tac no longer exists --

435 use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]

437 * HOL/typedef: fixed type inference for representing set; type

438 arguments now have to occur explicitly on the rhs as type constraints;

440 * ZF: The con_defs part of an inductive definition may no longer refer

441 to constants declared in the same theory;

443 * HOL, ZF: the function mk_cases, generated by the inductive

444 definition package, has lost an argument. To simplify its result, it

445 uses the default simpset instead of a supplied list of theorems.

447 * HOL/List: the constructors of type list are now Nil and Cons;

449 * Simplifier: the type of the infix ML functions

450 setSSolver addSSolver setSolver addSolver

451 is now simpset * solver -> simpset where `solver' is a new abstract type

452 for packaging solvers. A solver is created via

453 mk_solver: string -> (thm list -> int -> tactic) -> solver

454 where the string argument is only a comment.

457 *** Proof tools ***

459 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a

460 decision procedure for linear arithmetic. Currently it is used for

461 types `nat', `int', and `real' in HOL (see below); it can, should and

462 will be instantiated for other types and logics as well.

464 * The simplifier now accepts rewrite rules with flexible heads, eg

465 hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y

466 They are applied like any rule with a non-pattern lhs, i.e. by first-order

467 matching.

470 *** General ***

472 * New Isabelle/Isar subsystem provides an alternative to traditional

473 tactical theorem proving; together with the ProofGeneral/isar user

474 interface it offers an interactive environment for developing human

475 readable proof documents (Isar == Intelligible semi-automated

476 reasoning); for further information see isatool doc isar-ref,

477 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/

479 * improved and simplified presentation of theories: better HTML markup

480 (including colors), graph views in several sizes; isatool usedir now

481 provides a proper interface for user theories (via -P option); actual

482 document preparation based on (PDF)LaTeX is available as well (for

483 new-style theories only); see isatool doc system for more information;

485 * native support for Proof General, both for classic Isabelle and

486 Isabelle/Isar;

488 * ML function thm_deps visualizes dependencies of theorems and lemmas,

489 using the graph browser tool;

491 * Isabelle manuals now also available as PDF;

493 * theory loader rewritten from scratch (may not be fully

494 bug-compatible); old loadpath variable has been replaced by show_path,

495 add_path, del_path, reset_path functions; new operations such as

496 update_thy, touch_thy, remove_thy, use/update_thy_only (see also

497 isatool doc ref);

499 * improved isatool install: option -k creates KDE application icon,

500 option -p DIR installs standalone binaries;

502 * added ML_PLATFORM setting (useful for cross-platform installations);

503 more robust handling of platform specific ML images for SML/NJ;

505 * the settings environment is now statically scoped, i.e. it is never

506 created again in sub-processes invoked from isabelle, isatool, or

507 Isabelle;

509 * path element specification '~~' refers to '$ISABELLE_HOME';

511 * in locales, the "assumes" and "defines" parts may be omitted if

512 empty;

514 * new print_mode "xsymbols" for extended symbol support (e.g. genuine

515 long arrows);

517 * new print_mode "HTML";

519 * new flag show_tags controls display of tags of theorems (which are

520 basically just comments that may be attached by some tools);

522 * Isamode 2.6 requires patch to accomodate change of Isabelle font

523 mode and goal output format:

525 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el

526 244c244

527 < (list (isa-getenv "ISABELLE") "-msymbols" logic-name)

528 ---

529 > (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)

530 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el

531 181c181

532 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"

533 ---

534 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"

536 * function bind_thms stores lists of theorems (cf. bind_thm);

538 * new shorthand tactics ftac, eatac, datac, fatac;

540 * qed (and friends) now accept "" as result name; in that case the

541 theorem is not stored, but proper checks and presentation of the

542 result still apply;

544 * theorem database now also indexes constants "Trueprop", "all",

545 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;

548 *** HOL ***

550 ** HOL arithmetic **

552 * There are now decision procedures for linear arithmetic over nat and

553 int:

555 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',

556 `+', `-', `Suc', `min', `max' and numerical constants; other subterms

557 are treated as atomic; subformulae not involving type `nat' or `int'

558 are ignored; quantified subformulae are ignored unless they are

559 positive universal or negative existential. The tactic has to be

560 invoked by hand and can be a little bit slow. In particular, the

561 running time is exponential in the number of occurrences of `min' and

562 `max', and `-' on `nat'.

564 2. fast_arith_tac is a cut-down version of arith_tac: it only takes

565 (negated) (in)equalities among the premises and the conclusion into

566 account (i.e. no compound formulae) and does not know about `min' and

567 `max', and `-' on `nat'. It is fast and is used automatically by the

568 simplifier.

570 NB: At the moment, these decision procedures do not cope with mixed

571 nat/int formulae where the two parts interact, such as `m < n ==>

572 int(m) < int(n)'.

574 * HOL/Numeral provides a generic theory of numerals (encoded

575 efficiently as bit strings); setup for types nat/int/real is in place;

576 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than

577 int, existing theories and proof scripts may require a few additional

578 type constraints;

580 * integer division and remainder can now be performed on constant

581 arguments;

583 * many properties of integer multiplication, division and remainder

584 are now available;

586 * An interface to the Stanford Validity Checker (SVC) is available through the

587 tactic svc_tac. Propositional tautologies and theorems of linear arithmetic

588 are proved automatically. SVC must be installed separately, and its results

589 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any

590 invocation of the underlying oracle). For SVC see

591 http://verify.stanford.edu/SVC

593 * IsaMakefile: the HOL-Real target now builds an actual image;

596 ** HOL misc **

598 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces

599 (in Isabelle/Isar) -- by Gertrud Bauer;

601 * HOL/BCV: generic model of bytecode verification, i.e. data-flow

602 analysis for assembly languages with subtypes;

604 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization

605 -- avoids syntactic ambiguities and treats state, transition, and

606 temporal levels more uniformly; introduces INCOMPATIBILITIES due to

607 changed syntax and (many) tactics;

609 * HOL/inductive: Now also handles more general introduction rules such

610 as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity

611 theorems are now maintained within the theory (maintained via the

612 "mono" attribute);

614 * HOL/datatype: Now also handles arbitrarily branching datatypes

615 (using function types) such as

617 datatype 'a tree = Atom 'a | Branch "nat => 'a tree"

619 * HOL/record: record_simproc (part of the default simpset) takes care

620 of selectors applied to updated records; record_split_tac is no longer

621 part of the default claset; update_defs may now be removed from the

622 simpset in many cases; COMPATIBILITY: old behavior achieved by

624 claset_ref () := claset() addSWrapper record_split_wrapper;

625 Delsimprocs [record_simproc]

627 * HOL/typedef: fixed type inference for representing set; type

628 arguments now have to occur explicitly on the rhs as type constraints;

630 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem

631 names rather than an ML expression;

633 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be

634 supplied later. Program schemes can be defined, such as

635 "While B C s = (if B s then While B C (C s) else s)"

636 where the well-founded relation can be chosen after B and C have been given.

638 * HOL/List: the constructors of type list are now Nil and Cons;

639 INCOMPATIBILITY: while [] and infix # syntax is still there, of

640 course, ML tools referring to List.list.op # etc. have to be adapted;

642 * HOL_quantifiers flag superseded by "HOL" print mode, which is

643 disabled by default; run isabelle with option -m HOL to get back to

644 the original Gordon/HOL-style output;

646 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,

647 ALL x<=y. P, EX x<y. P, EX x<=y. P;

649 * HOL basic syntax simplified (more orthogonal): all variants of

650 All/Ex now support plain / symbolic / HOL notation; plain syntax for

651 Eps operator is provided as well: "SOME x. P[x]";

653 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;

655 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made

656 thus available for user theories;

658 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with

659 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the

660 time;

662 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec

663 several times and then mp;

666 *** LK ***

668 * the notation <<...>> is now available as a notation for sequences of

669 formulas;

671 * the simplifier is now installed

673 * the axiom system has been generalized (thanks to Soren Heilmann)

675 * the classical reasoner now has a default rule database

678 *** ZF ***

680 * new primrec section allows primitive recursive functions to be given

681 directly (as in HOL) over datatypes and the natural numbers;

683 * new tactics induct_tac and exhaust_tac for induction (or case

684 analysis) over datatypes and the natural numbers;

686 * the datatype declaration of type T now defines the recursor T_rec;

688 * simplification automatically does freeness reasoning for datatype

689 constructors;

691 * automatic type-inference, with AddTCs command to insert new

692 type-checking rules;

694 * datatype introduction rules are now added as Safe Introduction rules

695 to the claset;

697 * the syntax "if P then x else y" is now available in addition to

698 if(P,x,y);

701 *** Internal programming interfaces ***

703 * tuned simplifier trace output; new flag debug_simp;

705 * structures Vartab / Termtab (instances of TableFun) offer efficient

706 tables indexed by indexname_ord / term_ord (compatible with aconv);

708 * AxClass.axclass_tac lost the theory argument;

710 * tuned current_goals_markers semantics: begin / end goal avoids

711 printing empty lines;

713 * removed prs and prs_fn hook, which was broken because it did not

714 include \n in its semantics, forcing writeln to add one

715 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:

716 string -> unit if you really want to output text without newline;

718 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to

719 plain output, interface builders may have to enable 'isabelle_font'

720 mode to get Isabelle font glyphs as before;

722 * refined token_translation interface; INCOMPATIBILITY: output length

723 now of type real instead of int;

725 * theory loader actions may be traced via new ThyInfo.add_hook

726 interface (see src/Pure/Thy/thy_info.ML); example application: keep

727 your own database of information attached to *whole* theories -- as

728 opposed to intra-theory data slots offered via TheoryDataFun;

730 * proper handling of dangling sort hypotheses (at last!);

731 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing

732 extra sort hypotheses that can be witnessed from the type signature;

733 the force_strip_shyps flag is gone, any remaining shyps are simply

734 left in the theorem (with a warning issued by strip_shyps_warning);

738 New in Isabelle98-1 (October 1998)

739 ----------------------------------

741 *** Overview of INCOMPATIBILITIES (see below for more details) ***

743 * several changes of automated proof tools;

745 * HOL: major changes to the inductive and datatype packages, including

746 some minor incompatibilities of theory syntax;

748 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now

749 called `inj_on';

751 * HOL: removed duplicate thms in Arith:

752 less_imp_add_less should be replaced by trans_less_add1

753 le_imp_add_le should be replaced by trans_le_add1

755 * HOL: unary minus is now overloaded (new type constraints may be

756 required);

758 * HOL and ZF: unary minus for integers is now #- instead of #~. In

759 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is

760 now taken as an integer constant.

762 * Pure: ML function 'theory_of' renamed to 'theory';

765 *** Proof tools ***

767 * Simplifier:

768 1. Asm_full_simp_tac is now more aggressive.

769 1. It will sometimes reorient premises if that increases their power to

770 simplify.

771 2. It does no longer proceed strictly from left to right but may also

772 rotate premises to achieve further simplification.

773 For compatibility reasons there is now Asm_lr_simp_tac which is like the

774 old Asm_full_simp_tac in that it does not rotate premises.

775 2. The simplifier now knows a little bit about nat-arithmetic.

777 * Classical reasoner: wrapper mechanism for the classical reasoner now

778 allows for selected deletion of wrappers, by introduction of names for

779 wrapper functionals. This implies that addbefore, addSbefore,

780 addaltern, and addSaltern now take a pair (name, tactic) as argument,

781 and that adding two tactics with the same name overwrites the first

782 one (emitting a warning).

783 type wrapper = (int -> tactic) -> (int -> tactic)

784 setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by

785 addWrapper, addSWrapper: claset * (string * wrapper) -> claset

786 delWrapper, delSWrapper: claset * string -> claset

787 getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;

789 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE

790 semantics; addbefore now affects only the unsafe part of step_tac

791 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY

792 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac

793 by Force_tac;

795 * Classical reasoner: setwrapper to setWrapper and compwrapper to

796 compWrapper; added safe wrapper (and access functions for it);

798 * HOL/split_all_tac is now much faster and fails if there is nothing

799 to split. Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order

800 and the names of the automatically generated variables have changed.

801 split_all_tac has moved within claset() from unsafe wrappers to safe

802 wrappers, which means that !!-bound variables are split much more

803 aggressively, and safe_tac and clarify_tac now split such variables.

804 If this splitting is not appropriate, use delSWrapper "split_all_tac".

805 Note: the same holds for record_split_tac, which does the job of

806 split_all_tac for record fields.

808 * HOL/Simplifier: Rewrite rules for case distinctions can now be added

809 permanently to the default simpset using Addsplits just like

810 Addsimps. They can be removed via Delsplits just like

811 Delsimps. Lower-case versions are also available.

813 * HOL/Simplifier: The rule split_if is now part of the default

814 simpset. This means that the simplifier will eliminate all occurrences

815 of if-then-else in the conclusion of a goal. To prevent this, you can

816 either remove split_if completely from the default simpset by

817 `Delsplits [split_if]' or remove it in a specific call of the

818 simplifier using `... delsplits [split_if]'. You can also add/delete

819 other case splitting rules to/from the default simpset: every datatype

820 generates suitable rules `split_t_case' and `split_t_case_asm' (where

821 t is the name of the datatype).

823 * Classical reasoner / Simplifier combination: new force_tac (and

824 derivatives Force_tac, force) combines rewriting and classical

825 reasoning (and whatever other tools) similarly to auto_tac, but is

826 aimed to solve the given subgoal completely.

829 *** General ***

831 * new top-level commands `Goal' and `Goalw' that improve upon `goal'

832 and `goalw': the theory is no longer needed as an explicit argument -

833 the current theory context is used; assumptions are no longer returned

834 at the ML-level unless one of them starts with ==> or !!; it is

835 recommended to convert to these new commands using isatool fixgoal

836 (backup your sources first!);

838 * new top-level commands 'thm' and 'thms' for retrieving theorems from

839 the current theory context, and 'theory' to lookup stored theories;

841 * new theory section 'locale' for declaring constants, assumptions and

842 definitions that have local scope;

844 * new theory section 'nonterminals' for purely syntactic types;

846 * new theory section 'setup' for generic ML setup functions

847 (e.g. package initialization);

849 * the distribution now includes Isabelle icons: see

850 lib/logo/isabelle-{small,tiny}.xpm;

852 * isatool install - install binaries with absolute references to

853 ISABELLE_HOME/bin;

855 * isatool logo -- create instances of the Isabelle logo (as EPS);

857 * print mode 'emacs' reserved for Isamode;

859 * support multiple print (ast) translations per constant name;

861 * theorems involving oracles are now printed with a suffixed [!];

864 *** HOL ***

866 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');

868 * HOL/inductive package reorganized and improved: now supports mutual

869 definitions such as

871 inductive EVEN ODD

872 intrs

873 null "0 : EVEN"

874 oddI "n : EVEN ==> Suc n : ODD"

875 evenI "n : ODD ==> Suc n : EVEN"

877 new theorem list "elims" contains an elimination rule for each of the

878 recursive sets; inductive definitions now handle disjunctive premises

879 correctly (also ZF);

881 INCOMPATIBILITIES: requires Inductive as an ancestor; component

882 "mutual_induct" no longer exists - the induction rule is always

883 contained in "induct";

886 * HOL/datatype package re-implemented and greatly improved: now

887 supports mutually recursive datatypes such as

889 datatype

890 'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)

891 | SUM ('a aexp) ('a aexp)

892 | DIFF ('a aexp) ('a aexp)

893 | NUM 'a

894 and

895 'a bexp = LESS ('a aexp) ('a aexp)

896 | AND ('a bexp) ('a bexp)

897 | OR ('a bexp) ('a bexp)

899 as well as indirectly recursive datatypes such as

901 datatype

902 ('a, 'b) term = Var 'a

903 | App 'b ((('a, 'b) term) list)

905 The new tactic mutual_induct_tac [<var_1>, ..., <var_n>] i performs

906 induction on mutually / indirectly recursive datatypes.

908 Primrec equations are now stored in theory and can be accessed via

909 <function_name>.simps.

911 INCOMPATIBILITIES:

913 - Theories using datatypes must now have theory Datatype as an

914 ancestor.

915 - The specific <typename>.induct_tac no longer exists - use the

916 generic induct_tac instead.

917 - natE has been renamed to nat.exhaust - use exhaust_tac

918 instead of res_inst_tac ... natE. Note that the variable

919 names in nat.exhaust differ from the names in natE, this

920 may cause some "fragile" proofs to fail.

921 - The theorems split_<typename>_case and split_<typename>_case_asm

922 have been renamed to <typename>.split and <typename>.split_asm.

923 - Since default sorts of type variables are now handled correctly,

924 some datatype definitions may have to be annotated with explicit

925 sort constraints.

926 - Primrec definitions no longer require function name and type

927 of recursive argument.

929 Consider using isatool fixdatatype to adapt your theories and proof

930 scripts to the new package (backup your sources first!).

933 * HOL/record package: considerably improved implementation; now

934 includes concrete syntax for record types, terms, updates; theorems

935 for surjective pairing and splitting !!-bound record variables; proof

936 support is as follows:

938 1) standard conversions (selectors or updates applied to record

939 constructor terms) are part of the standard simpset;

941 2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are

942 made part of standard simpset and claset via addIffs;

944 3) a tactic for record field splitting (record_split_tac) is part of

945 the standard claset (addSWrapper);

947 To get a better idea about these rules you may retrieve them via

948 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is

949 the name of your record type.

951 The split tactic 3) conceptually simplifies by the following rule:

953 "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"

955 Thus any record variable that is bound by meta-all will automatically

956 blow up into some record constructor term, consequently the

957 simplifications of 1), 2) apply. Thus force_tac, auto_tac etc. shall

958 solve record problems automatically.

961 * reorganized the main HOL image: HOL/Integ and String loaded by

962 default; theory Main includes everything;

964 * automatic simplification of integer sums and comparisons, using cancellation;

966 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;

968 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;

970 * many new identities for unions, intersections, set difference, etc.;

972 * expand_if, expand_split, expand_sum_case and expand_nat_case are now

973 called split_if, split_split, split_sum_case and split_nat_case (to go

974 with add/delsplits);

976 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting

977 (?x::unit) = (); this is made part of the default simpset, which COULD

978 MAKE EXISTING PROOFS FAIL under rare circumstances (consider

979 'Delsimprocs [unit_eq_proc];' as last resort); also note that

980 unit_abs_eta_conv is added in order to counter the effect of

981 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by

982 %u.f();

984 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which

985 makes more sense);

987 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;

988 It and 'sym RS equals0D' are now in the default claset, giving automatic

989 disjointness reasoning but breaking a few old proofs.

991 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1

992 to 'converse' from 'inverse' (for compatibility with ZF and some

993 literature);

995 * HOL/recdef can now declare non-recursive functions, with {} supplied as

996 the well-founded relation;

998 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of

999 Compl A. The "Compl" syntax remains available as input syntax for this

1000 release ONLY.

1002 * HOL/Update: new theory of function updates:

1003 f(a:=b) == %x. if x=a then b else f x

1004 may also be iterated as in f(a:=b,c:=d,...);

1006 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;

1008 * HOL/List:

1009 - new function list_update written xs[i:=v] that updates the i-th

1010 list position. May also be iterated as in xs[i:=a,j:=b,...].

1011 - new function `upt' written [i..j(] which generates the list

1012 [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper

1013 bound write [i..j], which is a shorthand for [i..j+1(].

1014 - new lexicographic orderings and corresponding wellfoundedness theorems.

1016 * HOL/Arith:

1017 - removed 'pred' (predecessor) function;

1018 - generalized some theorems about n-1;

1019 - many new laws about "div" and "mod";

1020 - new laws about greatest common divisors (see theory ex/Primes);

1022 * HOL/Relation: renamed the relational operator r^-1 "converse"

1023 instead of "inverse";

1025 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness

1026 of the multiset ordering;

1028 * directory HOL/Real: a construction of the reals using Dedekind cuts

1029 (not included by default);

1031 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;

1033 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted

1034 programs, i.e. different program variables may have different types.

1036 * calling (stac rew i) now fails if "rew" has no effect on the goal

1037 [previously, this check worked only if the rewrite rule was unconditional]

1038 Now rew can involve either definitions or equalities (either == or =).

1041 *** ZF ***

1043 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains

1044 only the theorems proved on ZF.ML;

1046 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;

1047 It and 'sym RS equals0D' are now in the default claset, giving automatic

1048 disjointness reasoning but breaking a few old proofs.

1050 * ZF/Update: new theory of function updates

1051 with default rewrite rule f(x:=y) ` z = if(z=x, y, f`z)

1052 may also be iterated as in f(a:=b,c:=d,...);

1054 * in let x=t in u(x), neither t nor u(x) has to be an FOL term.

1056 * calling (stac rew i) now fails if "rew" has no effect on the goal

1057 [previously, this check worked only if the rewrite rule was unconditional]

1058 Now rew can involve either definitions or equalities (either == or =).

1060 * case_tac provided for compatibility with HOL

1061 (like the old excluded_middle_tac, but with subgoals swapped)

1064 *** Internal programming interfaces ***

1066 * Pure: several new basic modules made available for general use, see

1067 also src/Pure/README;

1069 * improved the theory data mechanism to support encapsulation (data

1070 kind name replaced by private Object.kind, acting as authorization

1071 key); new type-safe user interface via functor TheoryDataFun; generic

1072 print_data function becomes basically useless;

1074 * removed global_names compatibility flag -- all theory declarations

1075 are qualified by default;

1077 * module Pure/Syntax now offers quote / antiquote translation

1078 functions (useful for Hoare logic etc. with implicit dependencies);

1079 see HOL/ex/Antiquote for an example use;

1081 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->

1082 cterm -> thm;

1084 * new tactical CHANGED_GOAL for checking that a tactic modifies a

1085 subgoal;

1087 * Display.print_goals function moved to Locale.print_goals;

1089 * standard print function for goals supports current_goals_markers

1090 variable for marking begin of proof, end of proof, start of goal; the

1091 default is ("", "", ""); setting current_goals_markers := ("<proof>",

1092 "</proof>", "<goal>") causes SGML like tagged proof state printing,

1093 for example;

1097 New in Isabelle98 (January 1998)

1098 --------------------------------

1100 *** Overview of INCOMPATIBILITIES (see below for more details) ***

1102 * changed lexical syntax of terms / types: dots made part of long

1103 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";

1105 * simpset (and claset) reference variable replaced by functions

1106 simpset / simpset_ref;

1108 * no longer supports theory aliases (via merge) and non-trivial

1109 implicit merge of thms' signatures;

1111 * most internal names of constants changed due to qualified names;

1113 * changed Pure/Sequence interface (see Pure/seq.ML);

1116 *** General Changes ***

1118 * hierachically structured name spaces (for consts, types, axms, thms

1119 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of

1120 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:

1121 isatool fixdots ensures space after dots (e.g. "%x. x"); set

1122 long_names for fully qualified output names; NOTE: ML programs

1123 (special tactics, packages etc.) referring to internal names may have

1124 to be adapted to cope with fully qualified names; in case of severe

1125 backward campatibility problems try setting 'global_names' at compile

1126 time to have enrything declared within a flat name space; one may also

1127 fine tune name declarations in theories via the 'global' and 'local'

1128 section;

1130 * reimplemented the implicit simpset and claset using the new anytype

1131 data filed in signatures; references simpset:simpset ref etc. are

1132 replaced by functions simpset:unit->simpset and

1133 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp

1134 to patch your ML files accordingly;

1136 * HTML output now includes theory graph data for display with Java

1137 applet or isatool browser; data generated automatically via isatool

1138 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);

1140 * defs may now be conditional; improved rewrite_goals_tac to handle

1141 conditional equations;

1143 * defs now admits additional type arguments, using TYPE('a) syntax;

1145 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always

1146 creates a new theory node; implicit merge of thms' signatures is

1147 restricted to 'trivial' ones; COMPATIBILITY: one may have to use

1148 transfer:theory->thm->thm in (rare) cases;

1150 * improved handling of draft signatures / theories; draft thms (and

1151 ctyps, cterms) are automatically promoted to real ones;

1153 * slightly changed interfaces for oracles: admit many per theory, named

1154 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;

1156 * print_goals: optional output of const types (set show_consts and

1157 show_types);

1159 * improved output of warnings (###) and errors (***);

1161 * subgoal_tac displays a warning if the new subgoal has type variables;

1163 * removed old README and Makefiles;

1165 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;

1167 * removed obsolete init_pps and init_database;

1169 * deleted the obsolete tactical STATE, which was declared by

1170 fun STATE tacfun st = tacfun st st;

1172 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~

1173 (which abbreviates $HOME);

1175 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:

1176 use isatool fixseq to adapt your ML programs (this works for fully

1177 qualified references to the Sequence structure only!);

1179 * use_thy no longer requires writable current directory; it always

1180 reloads .ML *and* .thy file, if either one is out of date;

1183 *** Classical Reasoner ***

1185 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new

1186 tactics that use classical reasoning to simplify a subgoal without

1187 splitting it into several subgoals;

1189 * Safe_tac: like safe_tac but uses the default claset;

1192 *** Simplifier ***

1194 * added simplification meta rules:

1195 (asm_)(full_)simplify: simpset -> thm -> thm;

1197 * simplifier.ML no longer part of Pure -- has to be loaded by object

1198 logics (again);

1200 * added prems argument to simplification procedures;

1202 * HOL, FOL, ZF: added infix function `addsplits':

1203 instead of `<simpset> setloop (split_tac <thms>)'

1204 you can simply write `<simpset> addsplits <thms>'

1207 *** Syntax ***

1209 * TYPE('a) syntax for type reflection terms;

1211 * no longer handles consts with name "" -- declare as 'syntax' instead;

1213 * pretty printer: changed order of mixfix annotation preference (again!);

1215 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;

1218 *** HOL ***

1220 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.

1221 with `addloop' of the simplifier to faciliate case splitting in premises.

1223 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;

1225 * HOL/Auth: new protocol proofs including some for the Internet

1226 protocol TLS;

1228 * HOL/Map: new theory of `maps' a la VDM;

1230 * HOL/simplifier: simplification procedures nat_cancel_sums for

1231 cancelling out common nat summands from =, <, <= (in)equalities, or

1232 differences; simplification procedures nat_cancel_factor for

1233 cancelling common factor from =, <, <= (in)equalities over natural

1234 sums; nat_cancel contains both kinds of procedures, it is installed by

1235 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;

1237 * HOL/simplifier: terms of the form

1238 `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)' (or t=x)

1239 are rewritten to

1240 `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',

1241 and those of the form

1242 `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)' (or t=x)

1243 are rewritten to

1244 `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',

1246 * HOL/datatype

1247 Each datatype `t' now comes with a theorem `split_t_case' of the form

1249 P(t_case f1 ... fn x) =

1250 ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &

1251 ...

1252 (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))

1253 )

1255 and a theorem `split_t_case_asm' of the form

1257 P(t_case f1 ... fn x) =

1258 ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |

1259 ...

1260 (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))

1261 )

1262 which can be added to a simpset via `addsplits'. The existing theorems

1263 expand_list_case and expand_option_case have been renamed to

1264 split_list_case and split_option_case.

1266 * HOL/Arithmetic:

1267 - `pred n' is automatically converted to `n-1'.

1268 Users are strongly encouraged not to use `pred' any longer,

1269 because it will disappear altogether at some point.

1270 - Users are strongly encouraged to write "0 < n" rather than

1271 "n ~= 0". Theorems and proof tools have been modified towards this

1272 `standard'.

1274 * HOL/Lists:

1275 the function "set_of_list" has been renamed "set" (and its theorems too);

1276 the function "nth" now takes its arguments in the reverse order and

1277 has acquired the infix notation "!" as in "xs!n".

1279 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};

1281 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its

1282 specialist theorems (like UN1_I) are gone. Similarly for (INT x.B x);

1284 * HOL/record: extensible records with schematic structural subtyping

1285 (single inheritance); EXPERIMENTAL version demonstrating the encoding,

1286 still lacks various theorems and concrete record syntax;

1289 *** HOLCF ***

1291 * removed "axioms" and "generated by" sections;

1293 * replaced "ops" section by extended "consts" section, which is capable of

1294 handling the continuous function space "->" directly;

1296 * domain package:

1297 . proves theorems immediately and stores them in the theory,

1298 . creates hierachical name space,

1299 . now uses normal mixfix annotations (instead of cinfix...),

1300 . minor changes to some names and values (for consistency),

1301 . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,

1302 . separator between mutual domain defs: changed "," to "and",

1303 . improved handling of sort constraints; now they have to

1304 appear on the left-hand side of the equations only;

1306 * fixed LAM <x,y,zs>.b syntax;

1308 * added extended adm_tac to simplifier in HOLCF -- can now discharge

1309 adm (%x. P (t x)), where P is chainfinite and t continuous;

1312 *** FOL and ZF ***

1314 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.

1315 with `addloop' of the simplifier to faciliate case splitting in premises.

1317 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as

1318 in HOL, they strip ALL and --> from proved theorems;

1322 New in Isabelle94-8 (May 1997)

1323 ------------------------------

1325 *** General Changes ***

1327 * new utilities to build / run / maintain Isabelle etc. (in parts

1328 still somewhat experimental); old Makefiles etc. still functional;

1330 * new 'Isabelle System Manual';

1332 * INSTALL text, together with ./configure and ./build scripts;

1334 * reimplemented type inference for greater efficiency, better error

1335 messages and clean internal interface;

1337 * prlim command for dealing with lots of subgoals (an easier way of

1338 setting goals_limit);

1341 *** Syntax ***

1343 * supports alternative (named) syntax tables (parser and pretty

1344 printer); internal interface is provided by add_modesyntax(_i);

1346 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to

1347 be used in conjunction with the Isabelle symbol font; uses the

1348 "symbols" syntax table;

1350 * added token_translation interface (may translate name tokens in

1351 arbitrary ways, dependent on their type (free, bound, tfree, ...) and

1352 the current print_mode); IMPORTANT: user print translation functions

1353 are responsible for marking newly introduced bounds

1354 (Syntax.mark_boundT);

1356 * token translations for modes "xterm" and "xterm_color" that display

1357 names in bold, underline etc. or colors (which requires a color

1358 version of xterm);

1360 * infixes may now be declared with names independent of their syntax;

1362 * added typed_print_translation (like print_translation, but may

1363 access type of constant);

1366 *** Classical Reasoner ***

1368 Blast_tac: a new tactic! It is often more powerful than fast_tac, but has

1369 some limitations. Blast_tac...

1370 + ignores addss, addbefore, addafter; this restriction is intrinsic

1371 + ignores elimination rules that don't have the correct format

1372 (the conclusion MUST be a formula variable)

1373 + ignores types, which can make HOL proofs fail

1374 + rules must not require higher-order unification, e.g. apply_type in ZF

1375 [message "Function Var's argument not a bound variable" relates to this]

1376 + its proof strategy is more general but can actually be slower

1378 * substitution with equality assumptions no longer permutes other

1379 assumptions;

1381 * minor changes in semantics of addafter (now called addaltern); renamed

1382 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper

1383 (and access functions for it);

1385 * improved combination of classical reasoner and simplifier:

1386 + functions for handling clasimpsets

1387 + improvement of addss: now the simplifier is called _after_ the

1388 safe steps.

1389 + safe variant of addss called addSss: uses safe simplifications

1390 _during_ the safe steps. It is more complete as it allows multiple

1391 instantiations of unknowns (e.g. with slow_tac).

1393 *** Simplifier ***

1395 * added interface for simplification procedures (functions that

1396 produce *proven* rewrite rules on the fly, depending on current

1397 redex);

1399 * ordering on terms as parameter (used for ordered rewriting);

1401 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;

1403 * the solver is now split into a safe and an unsafe part.

1404 This should be invisible for the normal user, except that the

1405 functions setsolver and addsolver have been renamed to setSolver and

1406 addSolver; added safe_asm_full_simp_tac;

1409 *** HOL ***

1411 * a generic induction tactic `induct_tac' which works for all datatypes and

1412 also for type `nat';

1414 * a generic case distinction tactic `exhaust_tac' which works for all

1415 datatypes and also for type `nat';

1417 * each datatype comes with a function `size';

1419 * patterns in case expressions allow tuple patterns as arguments to

1420 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';

1422 * primrec now also works with type nat;

1424 * recdef: a new declaration form, allows general recursive functions to be

1425 defined in theory files. See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.

1427 * the constant for negation has been renamed from "not" to "Not" to

1428 harmonize with FOL, ZF, LK, etc.;

1430 * HOL/ex/LFilter theory of a corecursive "filter" functional for

1431 infinite lists;

1433 * HOL/Modelcheck demonstrates invocation of model checker oracle;

1435 * HOL/ex/Ring.thy declares cring_simp, which solves equational

1436 problems in commutative rings, using axiomatic type classes for + and *;

1438 * more examples in HOL/MiniML and HOL/Auth;

1440 * more default rewrite rules for quantifiers, union/intersection;

1442 * a new constant `arbitrary == @x.False';

1444 * HOLCF/IOA replaces old HOL/IOA;

1446 * HOLCF changes: derived all rules and arities

1447 + axiomatic type classes instead of classes

1448 + typedef instead of faking type definitions

1449 + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.

1450 + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po

1451 + eliminated the types void, one, tr

1452 + use unit lift and bool lift (with translations) instead of one and tr

1453 + eliminated blift from Lift3.thy (use Def instead of blift)

1454 all eliminated rules are derived as theorems --> no visible changes ;

1457 *** ZF ***

1459 * ZF now has Fast_tac, Simp_tac and Auto_tac. Union_iff is a now a default

1460 rewrite rule; this may affect some proofs. eq_cs is gone but can be put back

1461 as ZF_cs addSIs [equalityI];

1465 New in Isabelle94-7 (November 96)

1466 ---------------------------------

1468 * allowing negative levels (as offsets) in prlev and choplev;

1470 * super-linear speedup for large simplifications;

1472 * FOL, ZF and HOL now use miniscoping: rewriting pushes

1473 quantifications in as far as possible (COULD MAKE EXISTING PROOFS

1474 FAIL); can suppress it using the command Delsimps (ex_simps @

1475 all_simps); De Morgan laws are also now included, by default;

1477 * improved printing of ==> : ~:

1479 * new object-logic "Sequents" adds linear logic, while replacing LK

1480 and Modal (thanks to Sara Kalvala);

1482 * HOL/Auth: correctness proofs for authentication protocols;

1484 * HOL: new auto_tac combines rewriting and classical reasoning (many

1485 examples on HOL/Auth);

1487 * HOL: new command AddIffs for declaring theorems of the form P=Q to

1488 the rewriter and classical reasoner simultaneously;

1490 * function uresult no longer returns theorems in "standard" format;

1491 regain previous version by: val uresult = standard o uresult;

1495 New in Isabelle94-6

1496 -------------------

1498 * oracles -- these establish an interface between Isabelle and trusted

1499 external reasoners, which may deliver results as theorems;

1501 * proof objects (in particular record all uses of oracles);

1503 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;

1505 * "constdefs" section in theory files;

1507 * "primrec" section (HOL) no longer requires names;

1509 * internal type "tactic" now simply "thm -> thm Sequence.seq";

1513 New in Isabelle94-5

1514 -------------------

1516 * reduced space requirements;

1518 * automatic HTML generation from theories;

1520 * theory files no longer require "..." (quotes) around most types;

1522 * new examples, including two proofs of the Church-Rosser theorem;

1524 * non-curried (1994) version of HOL is no longer distributed;

1528 New in Isabelle94-4

1529 -------------------

1531 * greatly reduced space requirements;

1533 * theory files (.thy) no longer require \...\ escapes at line breaks;

1535 * searchable theorem database (see the section "Retrieving theorems" on

1536 page 8 of the Reference Manual);

1538 * new examples, including Grabczewski's monumental case study of the

1539 Axiom of Choice;

1541 * The previous version of HOL renamed to Old_HOL;

1543 * The new version of HOL (previously called CHOL) uses a curried syntax

1544 for functions. Application looks like f a b instead of f(a,b);

1546 * Mutually recursive inductive definitions finally work in HOL;

1548 * In ZF, pattern-matching on tuples is now available in all abstractions and

1549 translates to the operator "split";

1553 New in Isabelle94-3

1554 -------------------

1556 * new infix operator, addss, allowing the classical reasoner to

1557 perform simplification at each step of its search. Example:

1558 fast_tac (cs addss ss)

1560 * a new logic, CHOL, the same as HOL, but with a curried syntax

1561 for functions. Application looks like f a b instead of f(a,b). Also pairs

1562 look like (a,b) instead of <a,b>;

1564 * PLEASE NOTE: CHOL will eventually replace HOL!

1566 * In CHOL, pattern-matching on tuples is now available in all abstractions.

1567 It translates to the operator "split". A new theory of integers is available;

1569 * In ZF, integer numerals now denote two's-complement binary integers.

1570 Arithmetic operations can be performed by rewriting. See ZF/ex/Bin.ML;

1572 * Many new examples: I/O automata, Church-Rosser theorem, equivalents

1573 of the Axiom of Choice;

1577 New in Isabelle94-2

1578 -------------------

1580 * Significantly faster resolution;

1582 * the different sections in a .thy file can now be mixed and repeated

1583 freely;

1585 * Database of theorems for FOL, HOL and ZF. New

1586 commands including qed, qed_goal and bind_thm store theorems in the database.

1588 * Simple database queries: return a named theorem (get_thm) or all theorems of

1589 a given theory (thms_of), or find out what theory a theorem was proved in

1590 (theory_of_thm);

1592 * Bugs fixed in the inductive definition and datatype packages;

1594 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs

1595 and HOL_dup_cs obsolete;

1597 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1

1598 have been removed;

1600 * Simpler definition of function space in ZF;

1602 * new results about cardinal and ordinal arithmetic in ZF;

1604 * 'subtype' facility in HOL for introducing new types as subsets of existing

1605 types;

1608 $Id$