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NEWS

author | wenzelm |

Thu Aug 27 20:45:57 1998 +0200 (1998-08-27) | |

changeset 5399 | 0e3b58479d95 |

parent 5397 | 034ed25535b9 |

child 5407 | b450fea6d70c |

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

tuned;

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 * several changes of proof tools;

12 * HOL: new version of inductive and datatype;

14 * HOL: major changes to the inductive and datatype packages;

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

17 called `inj_on';

19 * HOL: removed duplicate thms in Arith:

20 less_imp_add_less should be replaced by trans_less_add1

21 le_imp_add_le should be replaced by trans_le_add1

23 * Pure: ML function 'theory_of' replaced by 'theory';

26 *** Proof tools ***

28 * Simplifier: Asm_full_simp_tac is now more aggressive.

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

30 simplify.

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

32 rotate premises to achieve further simplification.

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

34 old Asm_full_simp_tac in that it does not rotate premises.

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

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

38 wrapper functionals. This implies that addbefore, addSbefore,

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

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

41 one (emitting a warning).

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

43 setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by

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

45 delWrapper, delSWrapper: claset * string -> claset

46 getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;

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

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

50 order and the names of the automatically generated variables have

51 changed. split_all_tac has moved within claset() from unsafe wrappers

52 to safe wrappers, which means that !!-bound variables are split much

53 more aggressively, and safe_tac and clarify_tac now split such

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

55 "split_all_tac".

57 * HOL/Simplifier:

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

60 the default simpset using Addsplits just like Addsimps. They can be

61 removed via Delsplits just like Delsimps. Lower-case versions are

62 also available.

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

65 that the simplifier will eliminate all occurrences of if-then-else

66 in the conclusion of a goal. To prevent this, you can either remove

67 split_if completely from the default simpset by `Delsplits

68 [split_if]' or remove it in a specific call of the simplifier using

69 `... delsplits [split_if]'. You can also add/delete other case

70 splitting rules to/from the default simpset: every datatype

71 generates suitable rules `split_t_case' and `split_t_case_asm'

72 (where t is the name of the datatype).

74 * Classical reasoner - Simplifier combination: new force_tac (and

75 derivatives Force_tac, force) combines rewriting and classical

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

77 aimed to solve the given subgoal completely;

80 *** General ***

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

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

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

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

86 recommended to convert to these new commands using isatool fixgoal

87 (backup your sources first!);

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

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

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

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

95 (e.g. package initialization);

97 * the distribution now includes Isabelle icons: see

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

100 * isatool install - install binaries with absolute references to

101 ISABELLE_HOME/bin;

104 *** HOL ***

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

107 definitions such as

109 inductive EVEN ODD

110 intrs

111 null "0 : EVEN"

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

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

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

116 recursive sets; inductive definitions now handle disjunctive premises

117 correctly (also ZF);

119 INCOMPATIBILITIES: requires Inductive as an ancestor; component

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

121 contained in "induct";

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

125 supports mutually recursive datatypes such as

127 datatype

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

129 | SUM ('a aexp) ('a aexp)

130 | DIFF ('a aexp) ('a aexp)

131 | NUM 'a

132 and

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

134 | AND ('a bexp) ('a bexp)

135 | OR ('a bexp) ('a bexp)

137 as well as indirectly recursive datatypes such as

139 datatype

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

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

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

144 induction on mutually / indirectly recursive datatypes.

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

147 <function_name>.simps.

149 INCOMPATIBILITIES:

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

152 ancestor.

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

154 generic induct_tac instead.

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

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

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

158 may cause some "fragile" proofs to fail.

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

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

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

162 some datatype definitions may have to be annotated with explicit

163 sort constraints.

164 - Primrec definitions no longer require function name and type

165 of recursive argument.

167 Consider using isatool fixdatatype to adapt your theories and proof

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

171 * HOL/record package: now includes concrete syntax for record types,

172 terms, updates; still lacks important theorems, like surjective

173 pairing and split;

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

176 default; theory Main includes everything;

178 * added option_map_eq_Some to the default simpset claset;

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

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

184 * expand_if, expand_split, expand_sum_case and expand_nat_case are now

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

186 with add/delsplits);

188 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting

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

190 MAKE EXISTING PROOFS FAIL under rare circumstances (consider

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

192 unit_abs_eta_conv is added in order to counter the effect of

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

194 %u.f();

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

197 makes more sense);

199 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now called `equals0E' (the old name was misleading);

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

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

203 literature);

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

206 the well-founded relation;

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

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

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

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

214 * HOL/List:

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

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

217 - new lexicographic orderings and corresponding wellfoundedness theorems.

219 * HOL/Arith:

220 - removed 'pred' (predecessor) function;

221 - generalized some theorems about n-1;

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

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

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

226 instead of "inverse";

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

229 (not included by default);

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

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

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

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

238 *** ZF ***

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

241 only the theorems proved on ZF.ML;

243 * ZF INCOMPATIBILITY: rule `equals0D' is now called `equals0E' (the old name

244 was misleading). The rule and 'sym RS equals0E' are now in the default

245 claset, giving automatic disjointness reasoning but breaking a few old

246 proofs.

248 * ZF/Update: new theory of function updates

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

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

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

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

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

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

258 * case_tac provided for compatibility with HOL

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

262 *** Internal programming interfaces ***

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

265 also src/Pure/README;

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

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

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

270 print_data function becomes basically useless;

272 * removed global_names compatibility flag -- all theory declarations

273 are qualified by default;

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

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

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

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

280 cterm -> thm;

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

283 subgoal;

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

289 New in Isabelle98 (January 1998)

290 --------------------------------

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

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

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

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

298 simpset / simpset_ref;

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

301 implicit merge of thms' signatures;

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

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

308 *** General Changes ***

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

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

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

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

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

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

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

317 backward campatibility problems try setting 'global_names' at compile

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

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

320 section;

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

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

324 replaced by functions simpset:unit->simpset and

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

326 to patch your ML files accordingly;

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

329 applet or isatool browser; data generated automatically via isatool

330 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);

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

333 conditional equations;

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

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

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

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

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

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

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

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

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

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

349 show_types);

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

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

355 * removed old README and Makefiles;

357 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;

359 * removed obsolete init_pps and init_database;

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

362 fun STATE tacfun st = tacfun st st;

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

365 (which abbreviates $HOME);

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

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

369 qualified references to the Sequence structure only!);

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

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

375 *** Classical Reasoner ***

377 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new

378 tactics that use classical reasoning to simplify a subgoal without

379 splitting it into several subgoals;

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

384 *** Simplifier ***

386 * added simplification meta rules:

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

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

390 logics (again);

392 * added prems argument to simplification procedures;

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

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

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

399 *** Syntax ***

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

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

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

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

410 *** HOL ***

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

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

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

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

418 protocol TLS;

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

422 * HOL/simplifier: simplification procedures nat_cancel_sums for

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

424 differences; simplification procedures nat_cancel_factor for

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

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

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

429 * HOL/simplifier: terms of the form

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

431 are rewritten to

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

433 and those of the form

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

435 are rewritten to

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

438 * HOL/datatype

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

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

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

443 ...

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

445 )

447 and a theorem `split_t_case_asm' of the form

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

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

451 ...

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

453 )

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

455 expand_list_case and expand_option_case have been renamed to

456 split_list_case and split_option_case.

458 * HOL/Arithmetic:

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

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

461 because it will disappear altogether at some point.

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

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

464 `standard'.

466 * HOL/Lists:

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

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

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

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

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

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

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

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

478 still lacks various theorems and concrete record syntax;

481 *** HOLCF ***

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

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

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

488 * domain package:

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

490 . creates hierachical name space,

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

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

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

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

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

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

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

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

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

504 *** FOL and ZF ***

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

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

509 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as

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

514 New in Isabelle94-8 (May 1997)

515 ------------------------------

517 *** General Changes ***

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

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

522 * new 'Isabelle System Manual';

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

526 * reimplemented type inference for greater efficiency, better error

527 messages and clean internal interface;

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

530 setting goals_limit);

533 *** Syntax ***

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

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

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

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

540 "symbols" syntax table;

542 * added token_translation interface (may translate name tokens in

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

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

545 are responsible for marking newly introduced bounds

546 (Syntax.mark_boundT);

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

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

550 version of xterm);

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

554 * added typed_print_translation (like print_translation, but may

555 access type of constant);

558 *** Classical Reasoner ***

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

561 some limitations. Blast_tac...

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

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

564 (the conclusion MUST be a formula variable)

565 + ignores types, which can make HOL proofs fail

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

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

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

570 * substitution with equality assumptions no longer permutes other

571 assumptions;

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

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

575 (and access functions for it);

577 * improved combination of classical reasoner and simplifier:

578 + functions for handling clasimpsets

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

580 safe steps.

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

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

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

585 *** Simplifier ***

587 * added interface for simplification procedures (functions that

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

589 redex);

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

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

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

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

597 functions setsolver and addsolver have been renamed to setSolver and

598 addSolver; added safe_asm_full_simp_tac;

601 *** HOL ***

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

604 also for type `nat';

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

607 datatypes and also for type `nat';

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

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

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

614 * primrec now also works with type nat;

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

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

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

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

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

623 infinite lists;

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

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

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

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

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

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

636 * HOLCF/IOA replaces old HOL/IOA;

638 * HOLCF changes: derived all rules and arities

639 + axiomatic type classes instead of classes

640 + typedef instead of faking type definitions

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

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

643 + eliminated the types void, one, tr

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

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

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

649 *** ZF ***

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

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

653 as ZF_cs addSIs [equalityI];

657 New in Isabelle94-7 (November 96)

658 ---------------------------------

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

662 * super-linear speedup for large simplifications;

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

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

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

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

669 * improved printing of ==> : ~:

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

672 and Modal (thanks to Sara Kalvala);

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

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

677 examples on HOL/Auth);

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

680 the rewriter and classical reasoner simultaneously;

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

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

687 New in Isabelle94-6

688 -------------------

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

691 external reasoners, which may deliver results as theorems;

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

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

697 * "constdefs" section in theory files;

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

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

705 New in Isabelle94-5

706 -------------------

708 * reduced space requirements;

710 * automatic HTML generation from theories;

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

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

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

720 New in Isabelle94-4

721 -------------------

723 * greatly reduced space requirements;

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

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

728 page 8 of the Reference Manual);

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

731 Axiom of Choice;

733 * The previous version of HOL renamed to Old_HOL;

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

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

738 * Mutually recursive inductive definitions finally work in HOL;

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

741 translates to the operator "split";

745 New in Isabelle94-3

746 -------------------

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

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

750 fast_tac (cs addss ss)

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

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

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

756 * PLEASE NOTE: CHOL will eventually replace HOL!

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

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

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

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

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

765 of the Axiom of Choice;

769 New in Isabelle94-2

770 -------------------

772 * Significantly faster resolution;

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

775 freely;

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

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

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

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

782 (theory_of_thm);

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

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

787 and HOL_dup_cs obsolete;

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

790 have been removed;

792 * Simpler definition of function space in ZF;

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

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

797 types;

800 $Id$