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NEWS

author | paulson |

Wed May 06 13:01:45 1998 +0200 (1998-05-06) | |

changeset 4899 | 447d6b2956ba |

parent 4880 | 312115d20c45 |

child 4915 | 5ff99bd60da9 |

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

HOL/Update

2 Isabelle NEWS -- history of user-visible changes

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

5 New in Isabelle??? (FIXME)

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

8 *** General Changes ***

10 * Simplifier:

12 -Asm_full_simp_tac is now more aggressive:

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

14 simplify.

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

16 rotate premises to achieve further simplification.

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

18 old Asm_full_simp_tac in that it does not rotate premises.

20 * Changed wrapper mechanism for the classical reasoner now allows for

21 selected deletion of wrappers, by introduction of names for wrapper

22 functionals. This implies that addbefore, addSbefore, addaltern, and

23 addSaltern now take a pair (name, tactic) as argument, and that adding

24 two tactics with the same name overwrites the first one (emitting a

25 warning).

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

27 setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by

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

29 delWrapper, delSWrapper: claset * string -> claset

30 getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;

32 * inductive definitions now handle disjunctive premises correctly (HOL

33 and ZF);

35 * new toplevel commands 'thm' and 'thms' for retrieving theorems from

36 the current theory context;

38 * new theory section 'nonterminals';

40 * new theory section 'setup';

43 *** HOL ***

45 * new force_tac (and its derivations Force_tac, force): combines

46 rewriting and classical reasoning (and whatever other tools) similarly

47 to auto_tac, but is aimed to solve the given subgoal totally;

49 * added option_map_eq_Some to simpset() and claset()

51 * New theory HOL/Update of function updates:

52 f[a:=b] == %x. if x=a then b else f x

54 * New directory HOL/UNITY: Chandy and Misra's UNITY formalism

56 * split_all_tac is now much faster and fails if there is nothing to

57 split. Existing (fragile) proofs may require adaption because the

58 order and the names of the automatically generated variables have

59 changed. split_all_tac has moved within claset() from usafe wrappers

60 to safe wrappers, which means that !!-bound variables are splitted

61 much more aggressively, and safe_tac and clarify_tac now split such

62 variables. If this splitting is not appropriate, use delSWrapper

63 "split_all_tac".

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

67 * HOL/Arithmetic:

69 - removed 'pred' (predecessor) function

70 - generalized some theorems about n-1

71 - Many new laws about "div" and "mod"

72 - New laws about greatest common divisors (see theory ex/Primes)

74 * HOL/Relation: renamed the relational operatotr r^-1 "converse"

75 instead of "inverse";

77 * recdef can now declare non-recursive functions, with {} supplied as

78 the well-founded relation;

80 * expand_if, expand_split, expand_sum_case and expand_nat_case are now called

81 split_if, split_split, split_sum_case and split_nat_case

82 (to go with add/delsplits).

84 * Simplifier:

86 -Rewrite rules for case distinctions can now be added permanently to the

87 default simpset using Addsplits just like Addsimps. They can be removed via

88 Delsplits just like Delsimps. Lower-case versions are also available.

90 -The rule split_if is now part of the default simpset. This means that

91 the simplifier will eliminate all ocurrences of if-then-else in the

92 conclusion of a goal. To prevent this, you can either remove split_if

93 completely from the default simpset by `Delsplits [split_if]' or

94 remove it in a specific call of the simplifier using

95 `... delsplits [split_if]'.

96 You can also add/delete other case splitting rules to/from the default

97 simpset: every datatype generates a suitable rule `split_t_case' (where t

98 is the name of the datatype).

100 * new theory Vimage (inverse image of a function, syntax f-``B);

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

104 *** ZF ***

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

109 New in Isabelle98 (January 1998)

110 --------------------------------

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

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

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

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

118 simpset / simpset_ref;

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

121 implicit merge of thms' signatures;

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

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

128 *** General Changes ***

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

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

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

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

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

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

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

137 backward campatibility problems try setting 'global_names' at compile

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

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

140 section;

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

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

144 replaced by functions simpset:unit->simpset and

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

146 to patch your ML files accordingly;

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

149 applet or isatool browser; data generated automatically via isatool

150 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);

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

153 conditional equations;

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

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

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

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

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

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

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

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

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

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

169 show_types);

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

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

175 * removed old README and Makefiles;

177 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;

179 * removed obsolete init_pps and init_database;

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

182 fun STATE tacfun st = tacfun st st;

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

185 (which abbreviates $HOME);

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

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

189 qualified references to the Sequence structure only!);

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

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

195 *** Classical Reasoner ***

197 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new

198 tactics that use classical reasoning to simplify a subgoal without

199 splitting it into several subgoals;

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

204 *** Simplifier ***

206 * added simplification meta rules:

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

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

210 logics (again);

212 * added prems argument to simplification procedures;

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

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

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

219 *** Syntax ***

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

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

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

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

230 *** HOL ***

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

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

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

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

238 protocol TLS;

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

242 * HOL/simplifier: simplification procedures nat_cancel_sums for

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

244 differences; simplification procedures nat_cancel_factor for

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

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

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

249 * HOL/simplifier: terms of the form

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

251 are rewritten to

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

253 and those of the form

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

255 are rewritten to

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

258 * HOL/datatype

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

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

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

263 ...

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

265 )

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

268 expand_list_case and expand_option_case have been renamed to

269 split_list_case and split_option_case.

271 Additionally, there is a theorem `split_t_case_asm' of the form

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

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

275 ...

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

277 )

279 it be used with the new `split_asm_tac'.

281 * HOL/Arithmetic:

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

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

284 because it will disappear altogether at some point.

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

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

287 `standard'.

289 * HOL/Lists:

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

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

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

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

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

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

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

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

301 still lacks various theorems and concrete record syntax;

304 *** HOLCF ***

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

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

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

311 * domain package:

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

313 . creates hierachical name space,

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

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

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

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

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

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

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

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

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

327 *** FOL and ZF ***

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

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

332 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as

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

337 New in Isabelle94-8 (May 1997)

338 ------------------------------

340 *** General Changes ***

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

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

345 * new 'Isabelle System Manual';

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

349 * reimplemented type inference for greater efficiency, better error

350 messages and clean internal interface;

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

353 setting goals_limit);

356 *** Syntax ***

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

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

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

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

363 "symbols" syntax table;

365 * added token_translation interface (may translate name tokens in

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

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

368 are responsible for marking newly introduced bounds

369 (Syntax.mark_boundT);

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

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

373 version of xterm);

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

377 * added typed_print_translation (like print_translation, but may

378 access type of constant);

381 *** Classical Reasoner ***

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

384 some limitations. Blast_tac...

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

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

387 (the conclusion MUST be a formula variable)

388 + ignores types, which can make HOL proofs fail

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

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

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

393 * substitution with equality assumptions no longer permutes other

394 assumptions;

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

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

398 (and access functions for it);

400 * improved combination of classical reasoner and simplifier:

401 + functions for handling clasimpsets

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

403 safe steps.

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

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

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

408 *** Simplifier ***

410 * added interface for simplification procedures (functions that

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

412 redex);

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

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

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

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

420 functions setsolver and addsolver have been renamed to setSolver and

421 addSolver; added safe_asm_full_simp_tac;

424 *** HOL ***

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

427 also for type `nat';

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

430 datatypes and also for type `nat';

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

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

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

437 * primrec now also works with type nat;

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

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

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

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

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

446 infinite lists;

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

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

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

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

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

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

459 * HOLCF/IOA replaces old HOL/IOA;

461 * HOLCF changes: derived all rules and arities

462 + axiomatic type classes instead of classes

463 + typedef instead of faking type definitions

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

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

466 + eliminated the types void, one, tr

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

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

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

472 *** ZF ***

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

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

476 as ZF_cs addSIs [equalityI];

480 New in Isabelle94-7 (November 96)

481 ---------------------------------

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

485 * super-linear speedup for large simplifications;

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

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

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

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

492 * improved printing of ==> : ~:

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

495 and Modal (thanks to Sara Kalvala);

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

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

500 examples on HOL/Auth);

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

503 the rewriter and classical reasoner simultaneously;

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

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

510 New in Isabelle94-6

511 -------------------

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

514 external reasoners, which may deliver results as theorems;

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

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

520 * "constdefs" section in theory files;

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

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

528 New in Isabelle94-5

529 -------------------

531 * reduced space requirements;

533 * automatic HTML generation from theories;

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

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

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

543 New in Isabelle94-4

544 -------------------

546 * greatly reduced space requirements;

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

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

551 page 8 of the Reference Manual);

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

554 Axiom of Choice;

556 * The previous version of HOL renamed to Old_HOL;

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

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

561 * Mutually recursive inductive definitions finally work in HOL;

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

564 translates to the operator "split";

568 New in Isabelle94-3

569 -------------------

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

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

573 fast_tac (cs addss ss)

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

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

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

579 * PLEASE NOTE: CHOL will eventually replace HOL!

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

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

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

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

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

588 of the Axiom of Choice;

592 New in Isabelle94-2

593 -------------------

595 * Significantly faster resolution;

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

598 freely;

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

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

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

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

605 (theory_of_thm);

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

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

610 and HOL_dup_cs obsolete;

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

613 have been removed;

615 * Simpler definition of function space in ZF;

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

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

620 types;

623 $Id$