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NEWS

author | nipkow |

Fri Mar 10 17:14:56 2000 +0100 (2000-03-10) | |

changeset 8412 | 65f9089f6f71 |

parent 8392 | 5bf82327aa36 |

child 8425 | f03c667cf702 |

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

cases_tac

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: "case_tac" is now called "cases_tac" (see below)

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

15 *** Isabelle document preparation ***

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

18 including proper documents;

20 * generated LaTeX sources are now deleted after successful run

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

22 of isatool usedir;

24 * old-style theories now produce (crude) LaTeX sources as well;

27 *** Isar ***

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

31 * intro/elim/dest attributes: changed ! / !! flags to ? / ??;

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

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

35 Provers/classical ones!

37 * new 'obtain' language element supports generalized existence proofs;

39 * HOL: removed "case_split" thm binding, should use "cases" proof

40 method anyway;

42 * tuned syntax of "induct" method;

44 * new "cases" method for propositions, inductive sets and types;

47 *** HOL ***

49 * Algebra: new theory of rings and univariate polynomials, by Clemens

50 Ballarin;

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

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

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

56 Arithmetic, by Thomas M Rasmussen;

58 * There is a new tactic "cases_tac" for case distinctions; it subsumes the

59 old "case_tac" (no longer available) and "exhaust_tac" (which should no

60 longer be used).

62 *** General ***

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

65 of isabelle and isatool usedir;

69 New in Isabelle99 (October 1999)

70 --------------------------------

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

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

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

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

78 Delcongs [if_weak_cong];

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

81 complement;

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

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

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

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

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

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

92 to constants declared in the same theory;

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

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

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

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

100 * Simplifier: the type of the infix ML functions

101 setSSolver addSSolver setSolver addSolver

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

103 for packaging solvers. A solver is created via

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

105 where the string argument is only a comment.

108 *** Proof tools ***

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

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

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

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

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

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

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

118 matching.

121 *** General ***

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

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

125 interface it offers an interactive environment for developing human

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

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

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

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

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

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

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

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

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

137 Isabelle/Isar;

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

140 using the graph browser tool;

142 * Isabelle manuals now also available as PDF;

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

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

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

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

148 isatool doc ref);

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

151 option -p DIR installs standalone binaries;

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

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

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

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

158 Isabelle;

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

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

163 empty;

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

166 long arrows);

168 * new print_mode "HTML";

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

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

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

174 mode and goal output format:

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

177 244c244

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

179 ---

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

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

182 181c181

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

184 ---

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

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

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

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

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

193 result still apply;

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

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

199 *** HOL ***

201 ** HOL arithmetic **

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

204 int:

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

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

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

209 are ignored; quantified subformulae are ignored unless they are

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

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

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

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

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

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

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

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

219 simplifier.

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

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

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

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

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

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

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

229 type constraints;

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

232 arguments;

234 * many properties of integer multiplication, division and remainder

235 are now available;

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

238 tactic svc_tac. Propositional tautologies and theorems of linear arithmetic

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

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

241 invocation of the underlying oracle). For SVC see

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

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

247 ** HOL misc **

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

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

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

253 analysis for assembly languages with subtypes;

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

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

257 temporal levels more uniformly; introduces INCOMPATIBILITIES due to

258 changed syntax and (many) tactics;

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

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

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

263 "mono" attribute);

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

266 (using function types) such as

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

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

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

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

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

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

276 Delsimprocs [record_simproc]

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

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

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

282 names rather than an ML expression;

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

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

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

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

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

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

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

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

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

295 the original Gordon/HOL-style output;

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

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

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

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

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

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

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

307 thus available for user theories;

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

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

311 time;

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

314 several times and then mp;

317 *** LK ***

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

320 formulas;

322 * the simplifier is now installed

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

326 * the classical reasoner now has a default rule database

329 *** ZF ***

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

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

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

335 analysis) over datatypes and the natural numbers;

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

339 * simplification automatically does freeness reasoning for datatype

340 constructors;

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

343 type-checking rules;

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

346 to the claset;

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

349 if(P,x,y);

352 *** Internal programming interfaces ***

354 * tuned simplifier trace output; new flag debug_simp;

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

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

359 * AxClass.axclass_tac lost the theory argument;

361 * tuned current_goals_markers semantics: begin / end goal avoids

362 printing empty lines;

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

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

366 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:

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

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

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

371 mode to get Isabelle font glyphs as before;

373 * refined token_translation interface; INCOMPATIBILITY: output length

374 now of type real instead of int;

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

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

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

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

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

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

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

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

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

389 New in Isabelle98-1 (October 1998)

390 ----------------------------------

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

394 * several changes of automated proof tools;

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

397 some minor incompatibilities of theory syntax;

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

400 called `inj_on';

402 * HOL: removed duplicate thms in Arith:

403 less_imp_add_less should be replaced by trans_less_add1

404 le_imp_add_le should be replaced by trans_le_add1

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

407 required);

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

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

411 now taken as an integer constant.

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

416 *** Proof tools ***

418 * Simplifier:

419 1. Asm_full_simp_tac is now more aggressive.

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

421 simplify.

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

423 rotate premises to achieve further simplification.

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

425 old Asm_full_simp_tac in that it does not rotate premises.

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

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

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

430 wrapper functionals. This implies that addbefore, addSbefore,

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

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

433 one (emitting a warning).

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

435 setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by

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

437 delWrapper, delSWrapper: claset * string -> claset

438 getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;

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

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

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

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

444 by Force_tac;

446 * Classical reasoner: setwrapper to setWrapper and compwrapper to

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

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

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

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

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

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

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

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

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

457 split_all_tac for record fields.

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

460 permanently to the default simpset using Addsplits just like

461 Addsimps. They can be removed via Delsplits just like

462 Delsimps. Lower-case versions are also available.

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

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

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

467 either remove split_if completely from the default simpset by

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

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

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

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

472 t is the name of the datatype).

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

475 derivatives Force_tac, force) combines rewriting and classical

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

477 aimed to solve the given subgoal completely.

480 *** General ***

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

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

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

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

486 recommended to convert to these new commands using isatool fixgoal

487 (backup your sources first!);

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

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

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

493 definitions that have local scope;

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

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

498 (e.g. package initialization);

500 * the distribution now includes Isabelle icons: see

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

503 * isatool install - install binaries with absolute references to

504 ISABELLE_HOME/bin;

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

508 * print mode 'emacs' reserved for Isamode;

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

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

515 *** HOL ***

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

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

520 definitions such as

522 inductive EVEN ODD

523 intrs

524 null "0 : EVEN"

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

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

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

529 recursive sets; inductive definitions now handle disjunctive premises

530 correctly (also ZF);

532 INCOMPATIBILITIES: requires Inductive as an ancestor; component

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

534 contained in "induct";

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

538 supports mutually recursive datatypes such as

540 datatype

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

542 | SUM ('a aexp) ('a aexp)

543 | DIFF ('a aexp) ('a aexp)

544 | NUM 'a

545 and

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

547 | AND ('a bexp) ('a bexp)

548 | OR ('a bexp) ('a bexp)

550 as well as indirectly recursive datatypes such as

552 datatype

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

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

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

557 induction on mutually / indirectly recursive datatypes.

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

560 <function_name>.simps.

562 INCOMPATIBILITIES:

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

565 ancestor.

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

567 generic induct_tac instead.

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

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

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

571 may cause some "fragile" proofs to fail.

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

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

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

575 some datatype definitions may have to be annotated with explicit

576 sort constraints.

577 - Primrec definitions no longer require function name and type

578 of recursive argument.

580 Consider using isatool fixdatatype to adapt your theories and proof

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

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

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

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

587 support is as follows:

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

590 constructor terms) are part of the standard simpset;

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

593 made part of standard simpset and claset via addIffs;

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

596 the standard claset (addSWrapper);

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

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

600 the name of your record type.

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

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

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

607 blow up into some record constructor term, consequently the

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

609 solve record problems automatically.

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

613 default; theory Main includes everything;

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

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

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

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

623 * expand_if, expand_split, expand_sum_case and expand_nat_case are now

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

625 with add/delsplits);

627 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting

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

629 MAKE EXISTING PROOFS FAIL under rare circumstances (consider

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

631 unit_abs_eta_conv is added in order to counter the effect of

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

633 %u.f();

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

636 makes more sense);

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

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

640 disjointness reasoning but breaking a few old proofs.

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

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

644 literature);

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

647 the well-founded relation;

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

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

651 release ONLY.

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

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

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

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

659 * HOL/List:

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

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

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

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

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

665 - new lexicographic orderings and corresponding wellfoundedness theorems.

667 * HOL/Arith:

668 - removed 'pred' (predecessor) function;

669 - generalized some theorems about n-1;

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

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

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

674 instead of "inverse";

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

677 of the multiset ordering;

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

680 (not included by default);

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

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

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

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

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

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

692 *** ZF ***

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

695 only the theorems proved on ZF.ML;

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

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

699 disjointness reasoning but breaking a few old proofs.

701 * ZF/Update: new theory of function updates

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

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

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

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

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

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

711 * case_tac provided for compatibility with HOL

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

715 *** Internal programming interfaces ***

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

718 also src/Pure/README;

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

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

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

723 print_data function becomes basically useless;

725 * removed global_names compatibility flag -- all theory declarations

726 are qualified by default;

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

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

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

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

733 cterm -> thm;

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

736 subgoal;

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

740 * standard print function for goals supports current_goals_markers

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

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

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

744 for example;

748 New in Isabelle98 (January 1998)

749 --------------------------------

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

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

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

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

757 simpset / simpset_ref;

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

760 implicit merge of thms' signatures;

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

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

767 *** General Changes ***

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

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

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

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

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

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

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

776 backward campatibility problems try setting 'global_names' at compile

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

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

779 section;

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

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

783 replaced by functions simpset:unit->simpset and

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

785 to patch your ML files accordingly;

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

788 applet or isatool browser; data generated automatically via isatool

789 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);

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

792 conditional equations;

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

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

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

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

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

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

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

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

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

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

808 show_types);

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

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

814 * removed old README and Makefiles;

816 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;

818 * removed obsolete init_pps and init_database;

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

821 fun STATE tacfun st = tacfun st st;

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

824 (which abbreviates $HOME);

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

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

828 qualified references to the Sequence structure only!);

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

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

834 *** Classical Reasoner ***

836 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new

837 tactics that use classical reasoning to simplify a subgoal without

838 splitting it into several subgoals;

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

843 *** Simplifier ***

845 * added simplification meta rules:

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

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

849 logics (again);

851 * added prems argument to simplification procedures;

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

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

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

858 *** Syntax ***

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

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

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

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

869 *** HOL ***

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

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

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

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

877 protocol TLS;

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

881 * HOL/simplifier: simplification procedures nat_cancel_sums for

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

883 differences; simplification procedures nat_cancel_factor for

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

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

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

888 * HOL/simplifier: terms of the form

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

890 are rewritten to

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

892 and those of the form

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

894 are rewritten to

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

897 * HOL/datatype

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

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

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

902 ...

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

904 )

906 and a theorem `split_t_case_asm' of the form

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

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

910 ...

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

912 )

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

914 expand_list_case and expand_option_case have been renamed to

915 split_list_case and split_option_case.

917 * HOL/Arithmetic:

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

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

920 because it will disappear altogether at some point.

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

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

923 `standard'.

925 * HOL/Lists:

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

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

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

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

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

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

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

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

937 still lacks various theorems and concrete record syntax;

940 *** HOLCF ***

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

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

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

947 * domain package:

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

949 . creates hierachical name space,

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

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

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

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

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

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

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

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

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

963 *** FOL and ZF ***

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

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

968 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as

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

973 New in Isabelle94-8 (May 1997)

974 ------------------------------

976 *** General Changes ***

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

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

981 * new 'Isabelle System Manual';

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

985 * reimplemented type inference for greater efficiency, better error

986 messages and clean internal interface;

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

989 setting goals_limit);

992 *** Syntax ***

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

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

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

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

999 "symbols" syntax table;

1001 * added token_translation interface (may translate name tokens in

1002 arbitrary ways, dependent on their type (free, bound, tfree, ...) and

1003 the current print_mode); IMPORTANT: user print translation functions

1004 are responsible for marking newly introduced bounds

1005 (Syntax.mark_boundT);

1007 * token translations for modes "xterm" and "xterm_color" that display

1008 names in bold, underline etc. or colors (which requires a color

1009 version of xterm);

1011 * infixes may now be declared with names independent of their syntax;

1013 * added typed_print_translation (like print_translation, but may

1014 access type of constant);

1017 *** Classical Reasoner ***

1019 Blast_tac: a new tactic! It is often more powerful than fast_tac, but has

1020 some limitations. Blast_tac...

1021 + ignores addss, addbefore, addafter; this restriction is intrinsic

1022 + ignores elimination rules that don't have the correct format

1023 (the conclusion MUST be a formula variable)

1024 + ignores types, which can make HOL proofs fail

1025 + rules must not require higher-order unification, e.g. apply_type in ZF

1026 [message "Function Var's argument not a bound variable" relates to this]

1027 + its proof strategy is more general but can actually be slower

1029 * substitution with equality assumptions no longer permutes other

1030 assumptions;

1032 * minor changes in semantics of addafter (now called addaltern); renamed

1033 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper

1034 (and access functions for it);

1036 * improved combination of classical reasoner and simplifier:

1037 + functions for handling clasimpsets

1038 + improvement of addss: now the simplifier is called _after_ the

1039 safe steps.

1040 + safe variant of addss called addSss: uses safe simplifications

1041 _during_ the safe steps. It is more complete as it allows multiple

1042 instantiations of unknowns (e.g. with slow_tac).

1044 *** Simplifier ***

1046 * added interface for simplification procedures (functions that

1047 produce *proven* rewrite rules on the fly, depending on current

1048 redex);

1050 * ordering on terms as parameter (used for ordered rewriting);

1052 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;

1054 * the solver is now split into a safe and an unsafe part.

1055 This should be invisible for the normal user, except that the

1056 functions setsolver and addsolver have been renamed to setSolver and

1057 addSolver; added safe_asm_full_simp_tac;

1060 *** HOL ***

1062 * a generic induction tactic `induct_tac' which works for all datatypes and

1063 also for type `nat';

1065 * a generic case distinction tactic `exhaust_tac' which works for all

1066 datatypes and also for type `nat';

1068 * each datatype comes with a function `size';

1070 * patterns in case expressions allow tuple patterns as arguments to

1071 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';

1073 * primrec now also works with type nat;

1075 * recdef: a new declaration form, allows general recursive functions to be

1076 defined in theory files. See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.

1078 * the constant for negation has been renamed from "not" to "Not" to

1079 harmonize with FOL, ZF, LK, etc.;

1081 * HOL/ex/LFilter theory of a corecursive "filter" functional for

1082 infinite lists;

1084 * HOL/Modelcheck demonstrates invocation of model checker oracle;

1086 * HOL/ex/Ring.thy declares cring_simp, which solves equational

1087 problems in commutative rings, using axiomatic type classes for + and *;

1089 * more examples in HOL/MiniML and HOL/Auth;

1091 * more default rewrite rules for quantifiers, union/intersection;

1093 * a new constant `arbitrary == @x.False';

1095 * HOLCF/IOA replaces old HOL/IOA;

1097 * HOLCF changes: derived all rules and arities

1098 + axiomatic type classes instead of classes

1099 + typedef instead of faking type definitions

1100 + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.

1101 + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po

1102 + eliminated the types void, one, tr

1103 + use unit lift and bool lift (with translations) instead of one and tr

1104 + eliminated blift from Lift3.thy (use Def instead of blift)

1105 all eliminated rules are derived as theorems --> no visible changes ;

1108 *** ZF ***

1110 * ZF now has Fast_tac, Simp_tac and Auto_tac. Union_iff is a now a default

1111 rewrite rule; this may affect some proofs. eq_cs is gone but can be put back

1112 as ZF_cs addSIs [equalityI];

1116 New in Isabelle94-7 (November 96)

1117 ---------------------------------

1119 * allowing negative levels (as offsets) in prlev and choplev;

1121 * super-linear speedup for large simplifications;

1123 * FOL, ZF and HOL now use miniscoping: rewriting pushes

1124 quantifications in as far as possible (COULD MAKE EXISTING PROOFS

1125 FAIL); can suppress it using the command Delsimps (ex_simps @

1126 all_simps); De Morgan laws are also now included, by default;

1128 * improved printing of ==> : ~:

1130 * new object-logic "Sequents" adds linear logic, while replacing LK

1131 and Modal (thanks to Sara Kalvala);

1133 * HOL/Auth: correctness proofs for authentication protocols;

1135 * HOL: new auto_tac combines rewriting and classical reasoning (many

1136 examples on HOL/Auth);

1138 * HOL: new command AddIffs for declaring theorems of the form P=Q to

1139 the rewriter and classical reasoner simultaneously;

1141 * function uresult no longer returns theorems in "standard" format;

1142 regain previous version by: val uresult = standard o uresult;

1146 New in Isabelle94-6

1147 -------------------

1149 * oracles -- these establish an interface between Isabelle and trusted

1150 external reasoners, which may deliver results as theorems;

1152 * proof objects (in particular record all uses of oracles);

1154 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;

1156 * "constdefs" section in theory files;

1158 * "primrec" section (HOL) no longer requires names;

1160 * internal type "tactic" now simply "thm -> thm Sequence.seq";

1164 New in Isabelle94-5

1165 -------------------

1167 * reduced space requirements;

1169 * automatic HTML generation from theories;

1171 * theory files no longer require "..." (quotes) around most types;

1173 * new examples, including two proofs of the Church-Rosser theorem;

1175 * non-curried (1994) version of HOL is no longer distributed;

1179 New in Isabelle94-4

1180 -------------------

1182 * greatly reduced space requirements;

1184 * theory files (.thy) no longer require \...\ escapes at line breaks;

1186 * searchable theorem database (see the section "Retrieving theorems" on

1187 page 8 of the Reference Manual);

1189 * new examples, including Grabczewski's monumental case study of the

1190 Axiom of Choice;

1192 * The previous version of HOL renamed to Old_HOL;

1194 * The new version of HOL (previously called CHOL) uses a curried syntax

1195 for functions. Application looks like f a b instead of f(a,b);

1197 * Mutually recursive inductive definitions finally work in HOL;

1199 * In ZF, pattern-matching on tuples is now available in all abstractions and

1200 translates to the operator "split";

1204 New in Isabelle94-3

1205 -------------------

1207 * new infix operator, addss, allowing the classical reasoner to

1208 perform simplification at each step of its search. Example:

1209 fast_tac (cs addss ss)

1211 * a new logic, CHOL, the same as HOL, but with a curried syntax

1212 for functions. Application looks like f a b instead of f(a,b). Also pairs

1213 look like (a,b) instead of <a,b>;

1215 * PLEASE NOTE: CHOL will eventually replace HOL!

1217 * In CHOL, pattern-matching on tuples is now available in all abstractions.

1218 It translates to the operator "split". A new theory of integers is available;

1220 * In ZF, integer numerals now denote two's-complement binary integers.

1221 Arithmetic operations can be performed by rewriting. See ZF/ex/Bin.ML;

1223 * Many new examples: I/O automata, Church-Rosser theorem, equivalents

1224 of the Axiom of Choice;

1228 New in Isabelle94-2

1229 -------------------

1231 * Significantly faster resolution;

1233 * the different sections in a .thy file can now be mixed and repeated

1234 freely;

1236 * Database of theorems for FOL, HOL and ZF. New

1237 commands including qed, qed_goal and bind_thm store theorems in the database.

1239 * Simple database queries: return a named theorem (get_thm) or all theorems of

1240 a given theory (thms_of), or find out what theory a theorem was proved in

1241 (theory_of_thm);

1243 * Bugs fixed in the inductive definition and datatype packages;

1245 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs

1246 and HOL_dup_cs obsolete;

1248 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1

1249 have been removed;

1251 * Simpler definition of function space in ZF;

1253 * new results about cardinal and ordinal arithmetic in ZF;

1255 * 'subtype' facility in HOL for introducing new types as subsets of existing

1256 types;

1259 $Id$