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NEWS

author | paulson |

Fri Aug 11 13:27:17 2000 +0200 (2000-08-11) | |

changeset 9578 | ab26d6c8ebfe |

parent 9577 | 9e66e8ed8237 |

child 9612 | e6ba17cd012e |

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

new theory Integ/IntDiv and many more monotonicity laws, etc., for the integers

2 Isabelle NEWS -- history user-relevant changes

3 ==============================================

5 New in this Isabelle version

6 ----------------------------

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

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

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

12 issue the following ML commands:

14 Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;

15 Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];

17 * HOL: 0 is now overloaded, so the type constraint ::nat may sometimes be

18 needed;

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

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

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

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

26 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;

28 * HOL: simplification no longer dives into case-expressions;

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

31 f.simps instead of f.rules;

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

34 main HOL, but was unused); should better use HOL's datatype package

35 anyway;

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

38 instead);

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

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

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

44 internally;

46 * HOL, ZF: syntax for quotienting wrt an equivalence relation changed from

47 A/r to A//r;

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

51 * Isar/Provers: intro/elim/dest attributes: changed

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

53 should have to change intro!! to intro? only);

55 * Isar: changed syntax of local blocks from {{ }} to { };

57 * Provers: strengthened force_tac by using new first_best_tac;

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

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

61 use instead the strong form,

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

63 In HOL, FOL and ZF the function cla_make_elim will create such rules

64 from destruct-rules;

66 * Provers: safe_asm_full_simp_tac is no longer in the simplifier signature. Use

67 val safe_asm_full_simp_tac = generic_simp_tac true (true,true,true);

68 if required.

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

71 timing flag supersedes proof_timing and Toplevel.trace;

73 * ML: PureThy.add_thms/add_axioms/add_defs return theorems as well;

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

76 overloading (usually false);

78 * LaTeX: several changes of isabelle.sty;

81 *** Document preparation ***

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

84 contain antiquotations of thm/prop/term/typ to be presented according

85 to latex print mode; concrete syntax is like this: @{term[show_types]

86 "f(x) = a + x"};

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

89 including proper document sources;

91 * generated LaTeX sources are now deleted after successful run

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

93 of isatool usedir;

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

96 style files, achieving self-contained LaTeX sources;

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

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

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

102 graph for 'all sessions';

104 * several improvements in isabelle.sty; \isamarkupheader is now

105 \section by default;

108 *** Isar ***

110 * Pure: local results and corresponding term bindings are now subject

111 to Hindley-Milner polymorphism (similar to ML); this accommodates

112 incremental type-inference nicely;

114 * Pure: new derived language element 'obtain' supports generalized

115 existence reasoning;

117 * Pure: new calculational elements 'moreover' and 'ultimately' support

118 accumulation of results, without applying any rules yet;

120 * Pure: scalable support for case-analysis type proofs: new 'case'

121 language element refers to local contexts symbolically, as produced by

122 certain proof methods; internally, case names are attached to theorems

123 as "tags";

125 * Pure: theory command 'hide' removes declarations from

126 class/type/const name spaces;

128 * Pure: theory command 'defs' supports option "(overloaded)" to

129 indicate potential overloading;

131 * Pure: changed syntax of local blocks from {{ }} to { };

133 * Pure: syntax of sorts made 'inner', i.e. have to write "{a, b, c}"

134 instead of {a, b, c};

136 * Pure now provides its own version of intro/elim/dest attributes;

137 useful for building new logics, but beware of confusion with the

138 Provers/classical ones;

140 * Pure: the local context of (non-atomic) goals is provided via case

141 name 'antecedent';

143 * Pure: removed obsolete 'transfer' attribute (transfer of thms to the

144 current context is now done automatically);

146 * Pure: theory command 'method_setup' provides a simple interface for

147 definining proof methods in ML;

149 * Provers: splitter support (via 'split' attribute and 'simp' method

150 modifier); 'simp' method: 'only:' modifier removes loopers as well

151 (including splits);

153 * HOL: new proof method 'cases' and improved version of 'induct' now

154 support named cases; major packages (inductive, datatype, primrec,

155 recdef) support case names and properly name parameters;

157 * HOL: removed 'case_split' thm binding, should use 'cases' proof

158 method anyway;

160 * HOL/Calculation: new rules for substitution in inequalities

161 (monotonicity conditions are extracted to be proven at end);

163 * HOL: removed obsolete expand_if = split_if; theorems if_splits =

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

165 foo.split foo.split_asm for each datatype;

167 * names of theorems etc. may be natural numbers as well;

169 * Provers: intro/elim/dest attributes: changed intro/intro!/intro!!

170 flags to intro!/intro/intro? (in most cases, one should have to change

171 intro!! to intro? only);

173 * 'pr' command: optional goals_limit argument; no longer prints theory

174 contexts, but only proof states;

176 * diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit

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

178 proof state according to the Isabelle LaTeX style;

180 * improved support for emulating tactic scripts, including proof

181 methods 'tactic', 'res_inst_tac' etc., 'subgoal_tac', and 'case_tac' /

182 'induct_tac' (for HOL datatypes);

184 * simplified (more robust) goal selection of proof methods: 1st goal,

185 all goals, or explicit goal specifier (tactic emulation); thus 'proof

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

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

190 * removed 'help' command, which hasn't been too helpful anyway; should

191 instead use individual commands for printing items (print_commands,

192 print_methods etc.);

194 * added 'nothing' --- the empty list of theorems;

197 *** HOL ***

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

200 Clemens Ballarin;

202 * HOL/ex: new theory Factorization proving the Fundamental Theorem of

203 Arithmetic, by Thomas M Rasmussen;

205 * HOL/ex/Multiquote: multiple nested quotations and anti-quotations --

206 basically a generalized version of de-Bruijn representation; very

207 useful in avoiding lifting of operations;

209 * HOL/NumberTheory: Chinese Remainder Theorem, Fermat/Euler Theorem, Wilson's

210 Theorem, by Thomas M Rasmussen;

212 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog;

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

216 * HOL/record: fixed select-update simplification procedure to handle

217 extended records as well; admit "r" as field name;

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

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

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

223 Types nat and int belong to this axclass;

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

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

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

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

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

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

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

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

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

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

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

238 selector expression is simplified, but not the remaining arms. To

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

240 need to remove t.weak_case_cong from the simpset, either permanently

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

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

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

245 termination conditions are proved automatically, these simplification

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

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

248 each equation;

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

251 permits the definition of tail-recursive functions without the

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

253 invariant proof rule for while is applied.

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

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

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

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

261 HOL, but was unused);

263 * fewer consts declared as global (e.g. have to refer to "Lfp.lfp"

264 instead of "lfp" internally; affects ML packages only);

266 * tuned AST representation of nested pairs, avoiding bogus output in

267 case of overlap with user translations (e.g. judgements over tuples);

270 *** ZF ***

272 * simplification automatically cancels common terms in arithmetic expressions

273 over nat and int;

275 * new treatment of nat to minimize type-checking: all operators coerce their

276 operands to a natural number using the function natify, making the algebraic

277 laws unconditional;

279 * as above, for int: operators coerce their operands to an integer using the

280 function intify;

282 * the integer library now contains many of the usual laws for the orderings,

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

286 *** FOL & ZF ***

288 * AddIffs now available, giving theorems of the form P<->Q to the

289 simplifier and classical reasoner simultaneously;

292 *** General ***

294 * blast(_tac) now handles actual object-logic rules as assumptions;

295 note that auto(_tac) uses blast(_tac) internally, too;

297 * AST translation rules no longer require constant head on LHS;

299 * improved name spaces: ambiguous output is qualified; support for

300 hiding of names;

302 * compression of ML heaps images may now be controlled via -c option

303 of isabelle and isatool usedir (currently only observed by Poly/ML);

305 * provide TAGS file for Isabelle sources;

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

308 order;

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

311 timing flag supersedes proof_timing and Toplevel.trace;

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

314 overloading (usually false);

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

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

321 New in Isabelle99 (October 1999)

322 --------------------------------

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

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

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

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

330 Delcongs [if_weak_cong];

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

333 complement;

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

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

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

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

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

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

344 to constants declared in the same theory;

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

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

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

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

352 * Simplifier: the type of the infix ML functions

353 setSSolver addSSolver setSolver addSolver

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

355 for packaging solvers. A solver is created via

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

357 where the string argument is only a comment.

360 *** Proof tools ***

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

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

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

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

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

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

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

370 matching.

373 *** General ***

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

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

377 interface it offers an interactive environment for developing human

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

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

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

382 * improved presentation of theories: better HTML markup (including

383 colors), graph views in several sizes; isatool usedir now provides a

384 proper interface for user theories (via -P option); actual document

385 preparation based on (PDF)LaTeX is available as well (for new-style

386 theories only); see isatool doc system for more information;

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

389 Isabelle/Isar;

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

392 using the graph browser tool;

394 * Isabelle manuals now also available as PDF;

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

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

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

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

400 isatool doc ref);

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

403 option -p DIR installs standalone binaries;

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

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

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

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

410 Isabelle;

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

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

415 empty;

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

418 long arrows);

420 * new print_mode "HTML";

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

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

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

426 mode and goal output format:

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

429 244c244

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

431 ---

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

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

434 181c181

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

436 ---

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

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

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

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

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

445 result still apply;

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

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

451 *** HOL ***

453 ** HOL arithmetic **

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

456 int:

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

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

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

461 are ignored; quantified subformulae are ignored unless they are

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

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

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

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

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

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

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

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

471 simplifier.

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

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

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

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

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

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

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

481 type constraints;

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

484 arguments;

486 * many properties of integer multiplication, division and remainder

487 are now available;

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

490 tactic svc_tac. Propositional tautologies and theorems of linear arithmetic

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

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

493 invocation of the underlying oracle). For SVC see

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

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

499 ** HOL misc **

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

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

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

505 analysis for assembly languages with subtypes;

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

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

509 temporal levels more uniformly; introduces INCOMPATIBILITIES due to

510 changed syntax and (many) tactics;

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

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

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

515 "mono" attribute);

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

518 (using function types) such as

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

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

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

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

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

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

528 Delsimprocs [record_simproc]

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

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

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

534 names rather than an ML expression;

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

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

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

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

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

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

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

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

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

547 the original Gordon/HOL-style output;

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

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

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

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

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

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

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

559 thus available for user theories;

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

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

563 time;

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

566 several times and then mp;

569 *** LK ***

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

572 formulas;

574 * the simplifier is now installed

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

578 * the classical reasoner now has a default rule database

581 *** ZF ***

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

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

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

587 analysis) over datatypes and the natural numbers;

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

591 * simplification automatically does freeness reasoning for datatype

592 constructors;

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

595 type-checking rules;

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

598 to the claset;

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

601 if(P,x,y);

604 *** Internal programming interfaces ***

606 * tuned simplifier trace output; new flag debug_simp;

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

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

611 * AxClass.axclass_tac lost the theory argument;

613 * tuned current_goals_markers semantics: begin / end goal avoids

614 printing empty lines;

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

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

618 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:

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

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

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

623 mode to get Isabelle font glyphs as before;

625 * refined token_translation interface; INCOMPATIBILITY: output length

626 now of type real instead of int;

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

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

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

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

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

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

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

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

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

641 New in Isabelle98-1 (October 1998)

642 ----------------------------------

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

646 * several changes of automated proof tools;

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

649 some minor incompatibilities of theory syntax;

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

652 called `inj_on';

654 * HOL: removed duplicate thms in Arith:

655 less_imp_add_less should be replaced by trans_less_add1

656 le_imp_add_le should be replaced by trans_le_add1

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

659 required);

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

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

663 now taken as an integer constant.

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

668 *** Proof tools ***

670 * Simplifier:

671 1. Asm_full_simp_tac is now more aggressive.

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

673 simplify.

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

675 rotate premises to achieve further simplification.

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

677 old Asm_full_simp_tac in that it does not rotate premises.

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

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

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

682 wrapper functionals. This implies that addbefore, addSbefore,

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

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

685 one (emitting a warning).

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

687 setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by

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

689 delWrapper, delSWrapper: claset * string -> claset

690 getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;

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

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

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

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

696 by Force_tac;

698 * Classical reasoner: setwrapper to setWrapper and compwrapper to

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

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

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

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

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

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

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

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

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

709 split_all_tac for record fields.

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

712 permanently to the default simpset using Addsplits just like

713 Addsimps. They can be removed via Delsplits just like

714 Delsimps. Lower-case versions are also available.

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

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

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

719 either remove split_if completely from the default simpset by

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

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

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

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

724 t is the name of the datatype).

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

727 derivatives Force_tac, force) combines rewriting and classical

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

729 aimed to solve the given subgoal completely.

732 *** General ***

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

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

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

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

738 recommended to convert to these new commands using isatool fixgoal

739 (backup your sources first!);

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

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

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

745 definitions that have local scope;

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

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

750 (e.g. package initialization);

752 * the distribution now includes Isabelle icons: see

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

755 * isatool install - install binaries with absolute references to

756 ISABELLE_HOME/bin;

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

760 * print mode 'emacs' reserved for Isamode;

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

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

767 *** HOL ***

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

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

772 definitions such as

774 inductive EVEN ODD

775 intrs

776 null "0 : EVEN"

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

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

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

781 recursive sets; inductive definitions now handle disjunctive premises

782 correctly (also ZF);

784 INCOMPATIBILITIES: requires Inductive as an ancestor; component

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

786 contained in "induct";

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

790 supports mutually recursive datatypes such as

792 datatype

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

794 | SUM ('a aexp) ('a aexp)

795 | DIFF ('a aexp) ('a aexp)

796 | NUM 'a

797 and

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

799 | AND ('a bexp) ('a bexp)

800 | OR ('a bexp) ('a bexp)

802 as well as indirectly recursive datatypes such as

804 datatype

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

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

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

809 induction on mutually / indirectly recursive datatypes.

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

812 <function_name>.simps.

814 INCOMPATIBILITIES:

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

817 ancestor.

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

819 generic induct_tac instead.

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

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

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

823 may cause some "fragile" proofs to fail.

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

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

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

827 some datatype definitions may have to be annotated with explicit

828 sort constraints.

829 - Primrec definitions no longer require function name and type

830 of recursive argument.

832 Consider using isatool fixdatatype to adapt your theories and proof

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

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

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

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

839 support is as follows:

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

842 constructor terms) are part of the standard simpset;

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

845 made part of standard simpset and claset via addIffs;

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

848 the standard claset (addSWrapper);

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

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

852 the name of your record type.

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

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

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

859 blow up into some record constructor term, consequently the

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

861 solve record problems automatically.

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

865 default; theory Main includes everything;

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

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

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

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

875 * expand_if, expand_split, expand_sum_case and expand_nat_case are now

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

877 with add/delsplits);

879 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting

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

881 MAKE EXISTING PROOFS FAIL under rare circumstances (consider

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

883 unit_abs_eta_conv is added in order to counter the effect of

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

885 %u.f();

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

888 makes more sense);

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

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

892 disjointness reasoning but breaking a few old proofs.

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

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

896 literature);

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

899 the well-founded relation;

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

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

903 release ONLY.

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

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

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

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

911 * HOL/List:

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

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

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

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

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

917 - new lexicographic orderings and corresponding wellfoundedness theorems.

919 * HOL/Arith:

920 - removed 'pred' (predecessor) function;

921 - generalized some theorems about n-1;

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

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

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

926 instead of "inverse";

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

929 of the multiset ordering;

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

932 (not included by default);

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

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

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

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

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

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

944 *** ZF ***

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

947 only the theorems proved on ZF.ML;

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

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

951 disjointness reasoning but breaking a few old proofs.

953 * ZF/Update: new theory of function updates

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

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

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

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

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

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

963 * case_tac provided for compatibility with HOL

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

967 *** Internal programming interfaces ***

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

970 also src/Pure/README;

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

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

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

975 print_data function becomes basically useless;

977 * removed global_names compatibility flag -- all theory declarations

978 are qualified by default;

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

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

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

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

985 cterm -> thm;

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

988 subgoal;

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

992 * standard print function for goals supports current_goals_markers

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

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

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

996 for example;

1000 New in Isabelle98 (January 1998)

1001 --------------------------------

1003 *** Overview of INCOMPATIBILITIES (see below for more details) ***

1005 * changed lexical syntax of terms / types: dots made part of long

1006 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";

1008 * simpset (and claset) reference variable replaced by functions

1009 simpset / simpset_ref;

1011 * no longer supports theory aliases (via merge) and non-trivial

1012 implicit merge of thms' signatures;

1014 * most internal names of constants changed due to qualified names;

1016 * changed Pure/Sequence interface (see Pure/seq.ML);

1019 *** General Changes ***

1021 * hierachically structured name spaces (for consts, types, axms, thms

1022 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of

1023 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:

1024 isatool fixdots ensures space after dots (e.g. "%x. x"); set

1025 long_names for fully qualified output names; NOTE: ML programs

1026 (special tactics, packages etc.) referring to internal names may have

1027 to be adapted to cope with fully qualified names; in case of severe

1028 backward campatibility problems try setting 'global_names' at compile

1029 time to have enrything declared within a flat name space; one may also

1030 fine tune name declarations in theories via the 'global' and 'local'

1031 section;

1033 * reimplemented the implicit simpset and claset using the new anytype

1034 data filed in signatures; references simpset:simpset ref etc. are

1035 replaced by functions simpset:unit->simpset and

1036 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp

1037 to patch your ML files accordingly;

1039 * HTML output now includes theory graph data for display with Java

1040 applet or isatool browser; data generated automatically via isatool

1041 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);

1043 * defs may now be conditional; improved rewrite_goals_tac to handle

1044 conditional equations;

1046 * defs now admits additional type arguments, using TYPE('a) syntax;

1048 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always

1049 creates a new theory node; implicit merge of thms' signatures is

1050 restricted to 'trivial' ones; COMPATIBILITY: one may have to use

1051 transfer:theory->thm->thm in (rare) cases;

1053 * improved handling of draft signatures / theories; draft thms (and

1054 ctyps, cterms) are automatically promoted to real ones;

1056 * slightly changed interfaces for oracles: admit many per theory, named

1057 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;

1059 * print_goals: optional output of const types (set show_consts and

1060 show_types);

1062 * improved output of warnings (###) and errors (***);

1064 * subgoal_tac displays a warning if the new subgoal has type variables;

1066 * removed old README and Makefiles;

1068 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;

1070 * removed obsolete init_pps and init_database;

1072 * deleted the obsolete tactical STATE, which was declared by

1073 fun STATE tacfun st = tacfun st st;

1075 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~

1076 (which abbreviates $HOME);

1078 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:

1079 use isatool fixseq to adapt your ML programs (this works for fully

1080 qualified references to the Sequence structure only!);

1082 * use_thy no longer requires writable current directory; it always

1083 reloads .ML *and* .thy file, if either one is out of date;

1086 *** Classical Reasoner ***

1088 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new

1089 tactics that use classical reasoning to simplify a subgoal without

1090 splitting it into several subgoals;

1092 * Safe_tac: like safe_tac but uses the default claset;

1095 *** Simplifier ***

1097 * added simplification meta rules:

1098 (asm_)(full_)simplify: simpset -> thm -> thm;

1100 * simplifier.ML no longer part of Pure -- has to be loaded by object

1101 logics (again);

1103 * added prems argument to simplification procedures;

1105 * HOL, FOL, ZF: added infix function `addsplits':

1106 instead of `<simpset> setloop (split_tac <thms>)'

1107 you can simply write `<simpset> addsplits <thms>'

1110 *** Syntax ***

1112 * TYPE('a) syntax for type reflection terms;

1114 * no longer handles consts with name "" -- declare as 'syntax' instead;

1116 * pretty printer: changed order of mixfix annotation preference (again!);

1118 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;

1121 *** HOL ***

1123 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.

1124 with `addloop' of the simplifier to faciliate case splitting in premises.

1126 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;

1128 * HOL/Auth: new protocol proofs including some for the Internet

1129 protocol TLS;

1131 * HOL/Map: new theory of `maps' a la VDM;

1133 * HOL/simplifier: simplification procedures nat_cancel_sums for

1134 cancelling out common nat summands from =, <, <= (in)equalities, or

1135 differences; simplification procedures nat_cancel_factor for

1136 cancelling common factor from =, <, <= (in)equalities over natural

1137 sums; nat_cancel contains both kinds of procedures, it is installed by

1138 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;

1140 * HOL/simplifier: terms of the form

1141 `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)' (or t=x)

1142 are rewritten to

1143 `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',

1144 and those of the form

1145 `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)' (or t=x)

1146 are rewritten to

1147 `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',

1149 * HOL/datatype

1150 Each datatype `t' now comes with a theorem `split_t_case' of the form

1152 P(t_case f1 ... fn x) =

1153 ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &

1154 ...

1155 (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))

1156 )

1158 and a theorem `split_t_case_asm' of the form

1160 P(t_case f1 ... fn x) =

1161 ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |

1162 ...

1163 (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))

1164 )

1165 which can be added to a simpset via `addsplits'. The existing theorems

1166 expand_list_case and expand_option_case have been renamed to

1167 split_list_case and split_option_case.

1169 * HOL/Arithmetic:

1170 - `pred n' is automatically converted to `n-1'.

1171 Users are strongly encouraged not to use `pred' any longer,

1172 because it will disappear altogether at some point.

1173 - Users are strongly encouraged to write "0 < n" rather than

1174 "n ~= 0". Theorems and proof tools have been modified towards this

1175 `standard'.

1177 * HOL/Lists:

1178 the function "set_of_list" has been renamed "set" (and its theorems too);

1179 the function "nth" now takes its arguments in the reverse order and

1180 has acquired the infix notation "!" as in "xs!n".

1182 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};

1184 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its

1185 specialist theorems (like UN1_I) are gone. Similarly for (INT x.B x);

1187 * HOL/record: extensible records with schematic structural subtyping

1188 (single inheritance); EXPERIMENTAL version demonstrating the encoding,

1189 still lacks various theorems and concrete record syntax;

1192 *** HOLCF ***

1194 * removed "axioms" and "generated by" sections;

1196 * replaced "ops" section by extended "consts" section, which is capable of

1197 handling the continuous function space "->" directly;

1199 * domain package:

1200 . proves theorems immediately and stores them in the theory,

1201 . creates hierachical name space,

1202 . now uses normal mixfix annotations (instead of cinfix...),

1203 . minor changes to some names and values (for consistency),

1204 . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,

1205 . separator between mutual domain defs: changed "," to "and",

1206 . improved handling of sort constraints; now they have to

1207 appear on the left-hand side of the equations only;

1209 * fixed LAM <x,y,zs>.b syntax;

1211 * added extended adm_tac to simplifier in HOLCF -- can now discharge

1212 adm (%x. P (t x)), where P is chainfinite and t continuous;

1215 *** FOL and ZF ***

1217 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.

1218 with `addloop' of the simplifier to faciliate case splitting in premises.

1220 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as

1221 in HOL, they strip ALL and --> from proved theorems;

1225 New in Isabelle94-8 (May 1997)

1226 ------------------------------

1228 *** General Changes ***

1230 * new utilities to build / run / maintain Isabelle etc. (in parts

1231 still somewhat experimental); old Makefiles etc. still functional;

1233 * new 'Isabelle System Manual';

1235 * INSTALL text, together with ./configure and ./build scripts;

1237 * reimplemented type inference for greater efficiency, better error

1238 messages and clean internal interface;

1240 * prlim command for dealing with lots of subgoals (an easier way of

1241 setting goals_limit);

1244 *** Syntax ***

1246 * supports alternative (named) syntax tables (parser and pretty

1247 printer); internal interface is provided by add_modesyntax(_i);

1249 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to

1250 be used in conjunction with the Isabelle symbol font; uses the

1251 "symbols" syntax table;

1253 * added token_translation interface (may translate name tokens in

1254 arbitrary ways, dependent on their type (free, bound, tfree, ...) and

1255 the current print_mode); IMPORTANT: user print translation functions

1256 are responsible for marking newly introduced bounds

1257 (Syntax.mark_boundT);

1259 * token translations for modes "xterm" and "xterm_color" that display

1260 names in bold, underline etc. or colors (which requires a color

1261 version of xterm);

1263 * infixes may now be declared with names independent of their syntax;

1265 * added typed_print_translation (like print_translation, but may

1266 access type of constant);

1269 *** Classical Reasoner ***

1271 Blast_tac: a new tactic! It is often more powerful than fast_tac, but has

1272 some limitations. Blast_tac...

1273 + ignores addss, addbefore, addafter; this restriction is intrinsic

1274 + ignores elimination rules that don't have the correct format

1275 (the conclusion MUST be a formula variable)

1276 + ignores types, which can make HOL proofs fail

1277 + rules must not require higher-order unification, e.g. apply_type in ZF

1278 [message "Function Var's argument not a bound variable" relates to this]

1279 + its proof strategy is more general but can actually be slower

1281 * substitution with equality assumptions no longer permutes other

1282 assumptions;

1284 * minor changes in semantics of addafter (now called addaltern); renamed

1285 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper

1286 (and access functions for it);

1288 * improved combination of classical reasoner and simplifier:

1289 + functions for handling clasimpsets

1290 + improvement of addss: now the simplifier is called _after_ the

1291 safe steps.

1292 + safe variant of addss called addSss: uses safe simplifications

1293 _during_ the safe steps. It is more complete as it allows multiple

1294 instantiations of unknowns (e.g. with slow_tac).

1296 *** Simplifier ***

1298 * added interface for simplification procedures (functions that

1299 produce *proven* rewrite rules on the fly, depending on current

1300 redex);

1302 * ordering on terms as parameter (used for ordered rewriting);

1304 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;

1306 * the solver is now split into a safe and an unsafe part.

1307 This should be invisible for the normal user, except that the

1308 functions setsolver and addsolver have been renamed to setSolver and

1309 addSolver; added safe_asm_full_simp_tac;

1312 *** HOL ***

1314 * a generic induction tactic `induct_tac' which works for all datatypes and

1315 also for type `nat';

1317 * a generic case distinction tactic `exhaust_tac' which works for all

1318 datatypes and also for type `nat';

1320 * each datatype comes with a function `size';

1322 * patterns in case expressions allow tuple patterns as arguments to

1323 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';

1325 * primrec now also works with type nat;

1327 * recdef: a new declaration form, allows general recursive functions to be

1328 defined in theory files. See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.

1330 * the constant for negation has been renamed from "not" to "Not" to

1331 harmonize with FOL, ZF, LK, etc.;

1333 * HOL/ex/LFilter theory of a corecursive "filter" functional for

1334 infinite lists;

1336 * HOL/Modelcheck demonstrates invocation of model checker oracle;

1338 * HOL/ex/Ring.thy declares cring_simp, which solves equational

1339 problems in commutative rings, using axiomatic type classes for + and *;

1341 * more examples in HOL/MiniML and HOL/Auth;

1343 * more default rewrite rules for quantifiers, union/intersection;

1345 * a new constant `arbitrary == @x.False';

1347 * HOLCF/IOA replaces old HOL/IOA;

1349 * HOLCF changes: derived all rules and arities

1350 + axiomatic type classes instead of classes

1351 + typedef instead of faking type definitions

1352 + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.

1353 + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po

1354 + eliminated the types void, one, tr

1355 + use unit lift and bool lift (with translations) instead of one and tr

1356 + eliminated blift from Lift3.thy (use Def instead of blift)

1357 all eliminated rules are derived as theorems --> no visible changes ;

1360 *** ZF ***

1362 * ZF now has Fast_tac, Simp_tac and Auto_tac. Union_iff is a now a default

1363 rewrite rule; this may affect some proofs. eq_cs is gone but can be put back

1364 as ZF_cs addSIs [equalityI];

1368 New in Isabelle94-7 (November 96)

1369 ---------------------------------

1371 * allowing negative levels (as offsets) in prlev and choplev;

1373 * super-linear speedup for large simplifications;

1375 * FOL, ZF and HOL now use miniscoping: rewriting pushes

1376 quantifications in as far as possible (COULD MAKE EXISTING PROOFS

1377 FAIL); can suppress it using the command Delsimps (ex_simps @

1378 all_simps); De Morgan laws are also now included, by default;

1380 * improved printing of ==> : ~:

1382 * new object-logic "Sequents" adds linear logic, while replacing LK

1383 and Modal (thanks to Sara Kalvala);

1385 * HOL/Auth: correctness proofs for authentication protocols;

1387 * HOL: new auto_tac combines rewriting and classical reasoning (many

1388 examples on HOL/Auth);

1390 * HOL: new command AddIffs for declaring theorems of the form P=Q to

1391 the rewriter and classical reasoner simultaneously;

1393 * function uresult no longer returns theorems in "standard" format;

1394 regain previous version by: val uresult = standard o uresult;

1398 New in Isabelle94-6

1399 -------------------

1401 * oracles -- these establish an interface between Isabelle and trusted

1402 external reasoners, which may deliver results as theorems;

1404 * proof objects (in particular record all uses of oracles);

1406 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;

1408 * "constdefs" section in theory files;

1410 * "primrec" section (HOL) no longer requires names;

1412 * internal type "tactic" now simply "thm -> thm Sequence.seq";

1416 New in Isabelle94-5

1417 -------------------

1419 * reduced space requirements;

1421 * automatic HTML generation from theories;

1423 * theory files no longer require "..." (quotes) around most types;

1425 * new examples, including two proofs of the Church-Rosser theorem;

1427 * non-curried (1994) version of HOL is no longer distributed;

1431 New in Isabelle94-4

1432 -------------------

1434 * greatly reduced space requirements;

1436 * theory files (.thy) no longer require \...\ escapes at line breaks;

1438 * searchable theorem database (see the section "Retrieving theorems" on

1439 page 8 of the Reference Manual);

1441 * new examples, including Grabczewski's monumental case study of the

1442 Axiom of Choice;

1444 * The previous version of HOL renamed to Old_HOL;

1446 * The new version of HOL (previously called CHOL) uses a curried syntax

1447 for functions. Application looks like f a b instead of f(a,b);

1449 * Mutually recursive inductive definitions finally work in HOL;

1451 * In ZF, pattern-matching on tuples is now available in all abstractions and

1452 translates to the operator "split";

1456 New in Isabelle94-3

1457 -------------------

1459 * new infix operator, addss, allowing the classical reasoner to

1460 perform simplification at each step of its search. Example:

1461 fast_tac (cs addss ss)

1463 * a new logic, CHOL, the same as HOL, but with a curried syntax

1464 for functions. Application looks like f a b instead of f(a,b). Also pairs

1465 look like (a,b) instead of <a,b>;

1467 * PLEASE NOTE: CHOL will eventually replace HOL!

1469 * In CHOL, pattern-matching on tuples is now available in all abstractions.

1470 It translates to the operator "split". A new theory of integers is available;

1472 * In ZF, integer numerals now denote two's-complement binary integers.

1473 Arithmetic operations can be performed by rewriting. See ZF/ex/Bin.ML;

1475 * Many new examples: I/O automata, Church-Rosser theorem, equivalents

1476 of the Axiom of Choice;

1480 New in Isabelle94-2

1481 -------------------

1483 * Significantly faster resolution;

1485 * the different sections in a .thy file can now be mixed and repeated

1486 freely;

1488 * Database of theorems for FOL, HOL and ZF. New

1489 commands including qed, qed_goal and bind_thm store theorems in the database.

1491 * Simple database queries: return a named theorem (get_thm) or all theorems of

1492 a given theory (thms_of), or find out what theory a theorem was proved in

1493 (theory_of_thm);

1495 * Bugs fixed in the inductive definition and datatype packages;

1497 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs

1498 and HOL_dup_cs obsolete;

1500 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1

1501 have been removed;

1503 * Simpler definition of function space in ZF;

1505 * new results about cardinal and ordinal arithmetic in ZF;

1507 * 'subtype' facility in HOL for introducing new types as subsets of existing

1508 types;

1511 $Id$