2 Isabelle NEWS -- history user-relevant changes
3 ==============================================
5 New in this Isabelle version
6 ----------------------------
10 * tuned current_goals_markers semantics: begin / end goal avoids
14 New in Isabelle98-1 (October 1998)
15 ----------------------------------
17 *** Overview of INCOMPATIBILITIES (see below for more details) ***
19 * several changes of automated proof tools;
21 * HOL: major changes to the inductive and datatype packages, including
22 some minor incompatibilities of theory syntax;
24 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
27 * HOL: removed duplicate thms in Arith:
28 less_imp_add_less should be replaced by trans_less_add1
29 le_imp_add_le should be replaced by trans_le_add1
31 * HOL: unary minus is now overloaded (new type constraints may be
34 * HOL and ZF: unary minus for integers is now #- instead of #~. In
35 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
36 now taken as an integer constant.
38 * Pure: ML function 'theory_of' renamed to 'theory';
44 1. Asm_full_simp_tac is now more aggressive.
45 1. It will sometimes reorient premises if that increases their power to
47 2. It does no longer proceed strictly from left to right but may also
48 rotate premises to achieve further simplification.
49 For compatibility reasons there is now Asm_lr_simp_tac which is like the
50 old Asm_full_simp_tac in that it does not rotate premises.
51 2. The simplifier now knows a little bit about nat-arithmetic.
53 * Classical reasoner: wrapper mechanism for the classical reasoner now
54 allows for selected deletion of wrappers, by introduction of names for
55 wrapper functionals. This implies that addbefore, addSbefore,
56 addaltern, and addSaltern now take a pair (name, tactic) as argument,
57 and that adding two tactics with the same name overwrites the first
58 one (emitting a warning).
59 type wrapper = (int -> tactic) -> (int -> tactic)
60 setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
61 addWrapper, addSWrapper: claset * (string * wrapper) -> claset
62 delWrapper, delSWrapper: claset * string -> claset
63 getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
65 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
66 semantics; addbefore now affects only the unsafe part of step_tac
67 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
68 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
71 * Classical reasoner: setwrapper to setWrapper and compwrapper to
72 compWrapper; added safe wrapper (and access functions for it);
74 * HOL/split_all_tac is now much faster and fails if there is nothing
75 to split. Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
76 and the names of the automatically generated variables have changed.
77 split_all_tac has moved within claset() from unsafe wrappers to safe
78 wrappers, which means that !!-bound variables are split much more
79 aggressively, and safe_tac and clarify_tac now split such variables.
80 If this splitting is not appropriate, use delSWrapper "split_all_tac".
81 Note: the same holds for record_split_tac, which does the job of
82 split_all_tac for record fields.
84 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
85 permanently to the default simpset using Addsplits just like
86 Addsimps. They can be removed via Delsplits just like
87 Delsimps. Lower-case versions are also available.
89 * HOL/Simplifier: The rule split_if is now part of the default
90 simpset. This means that the simplifier will eliminate all occurrences
91 of if-then-else in the conclusion of a goal. To prevent this, you can
92 either remove split_if completely from the default simpset by
93 `Delsplits [split_if]' or remove it in a specific call of the
94 simplifier using `... delsplits [split_if]'. You can also add/delete
95 other case splitting rules to/from the default simpset: every datatype
96 generates suitable rules `split_t_case' and `split_t_case_asm' (where
97 t is the name of the datatype).
99 * Classical reasoner / Simplifier combination: new force_tac (and
100 derivatives Force_tac, force) combines rewriting and classical
101 reasoning (and whatever other tools) similarly to auto_tac, but is
102 aimed to solve the given subgoal completely.
107 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
108 and `goalw': the theory is no longer needed as an explicit argument -
109 the current theory context is used; assumptions are no longer returned
110 at the ML-level unless one of them starts with ==> or !!; it is
111 recommended to convert to these new commands using isatool fixgoal
112 (backup your sources first!);
114 * new top-level commands 'thm' and 'thms' for retrieving theorems from
115 the current theory context, and 'theory' to lookup stored theories;
117 * new theory section 'locale' for declaring constants, assumptions and
118 definitions that have local scope;
120 * new theory section 'nonterminals' for purely syntactic types;
122 * new theory section 'setup' for generic ML setup functions
123 (e.g. package initialization);
125 * the distribution now includes Isabelle icons: see
126 lib/logo/isabelle-{small,tiny}.xpm;
128 * isatool install - install binaries with absolute references to
131 * isatool logo -- create instances of the Isabelle logo (as EPS);
133 * print mode 'emacs' reserved for Isamode;
135 * support multiple print (ast) translations per constant name;
140 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
142 * HOL/inductive package reorganized and improved: now supports mutual
148 oddI "n : EVEN ==> Suc n : ODD"
149 evenI "n : ODD ==> Suc n : EVEN"
151 new theorem list "elims" contains an elimination rule for each of the
152 recursive sets; inductive definitions now handle disjunctive premises
155 INCOMPATIBILITIES: requires Inductive as an ancestor; component
156 "mutual_induct" no longer exists - the induction rule is always
157 contained in "induct";
160 * HOL/datatype package re-implemented and greatly improved: now
161 supports mutually recursive datatypes such as
164 'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
165 | SUM ('a aexp) ('a aexp)
166 | DIFF ('a aexp) ('a aexp)
169 'a bexp = LESS ('a aexp) ('a aexp)
170 | AND ('a bexp) ('a bexp)
171 | OR ('a bexp) ('a bexp)
173 as well as indirectly recursive datatypes such as
176 ('a, 'b) term = Var 'a
177 | App 'b ((('a, 'b) term) list)
179 The new tactic mutual_induct_tac [<var_1>, ..., <var_n>] i performs
180 induction on mutually / indirectly recursive datatypes.
182 Primrec equations are now stored in theory and can be accessed via
183 <function_name>.simps.
187 - Theories using datatypes must now have theory Datatype as an
189 - The specific <typename>.induct_tac no longer exists - use the
190 generic induct_tac instead.
191 - natE has been renamed to nat.exhaust - use exhaust_tac
192 instead of res_inst_tac ... natE. Note that the variable
193 names in nat.exhaust differ from the names in natE, this
194 may cause some "fragile" proofs to fail.
195 - The theorems split_<typename>_case and split_<typename>_case_asm
196 have been renamed to <typename>.split and <typename>.split_asm.
197 - Since default sorts of type variables are now handled correctly,
198 some datatype definitions may have to be annotated with explicit
200 - Primrec definitions no longer require function name and type
201 of recursive argument.
203 Consider using isatool fixdatatype to adapt your theories and proof
204 scripts to the new package (backup your sources first!).
207 * HOL/record package: considerably improved implementation; now
208 includes concrete syntax for record types, terms, updates; theorems
209 for surjective pairing and splitting !!-bound record variables; proof
210 support is as follows:
212 1) standard conversions (selectors or updates applied to record
213 constructor terms) are part of the standard simpset;
215 2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
216 made part of standard simpset and claset via addIffs;
218 3) a tactic for record field splitting (record_split_tac) is part of
219 the standard claset (addSWrapper);
221 To get a better idea about these rules you may retrieve them via
222 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
223 the name of your record type.
225 The split tactic 3) conceptually simplifies by the following rule:
227 "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
229 Thus any record variable that is bound by meta-all will automatically
230 blow up into some record constructor term, consequently the
231 simplifications of 1), 2) apply. Thus force_tac, auto_tac etc. shall
232 solve record problems automatically.
235 * reorganized the main HOL image: HOL/Integ and String loaded by
236 default; theory Main includes everything;
238 * automatic simplification of integer sums and comparisons, using cancellation;
240 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
242 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
244 * many new identities for unions, intersections, set difference, etc.;
246 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
247 called split_if, split_split, split_sum_case and split_nat_case (to go
250 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
251 (?x::unit) = (); this is made part of the default simpset, which COULD
252 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
253 'Delsimprocs [unit_eq_proc];' as last resort); also note that
254 unit_abs_eta_conv is added in order to counter the effect of
255 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
258 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
261 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
262 It and 'sym RS equals0D' are now in the default claset, giving automatic
263 disjointness reasoning but breaking a few old proofs.
265 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
266 to 'converse' from 'inverse' (for compatibility with ZF and some
269 * HOL/recdef can now declare non-recursive functions, with {} supplied as
270 the well-founded relation;
272 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
273 Compl A. The "Compl" syntax remains available as input syntax for this
276 * HOL/Update: new theory of function updates:
277 f(a:=b) == %x. if x=a then b else f x
278 may also be iterated as in f(a:=b,c:=d,...);
280 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
283 - new function list_update written xs[i:=v] that updates the i-th
284 list position. May also be iterated as in xs[i:=a,j:=b,...].
285 - new function `upt' written [i..j(] which generates the list
286 [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
287 bound write [i..j], which is a shorthand for [i..j+1(].
288 - new lexicographic orderings and corresponding wellfoundedness theorems.
291 - removed 'pred' (predecessor) function;
292 - generalized some theorems about n-1;
293 - many new laws about "div" and "mod";
294 - new laws about greatest common divisors (see theory ex/Primes);
296 * HOL/Relation: renamed the relational operator r^-1 "converse"
297 instead of "inverse";
299 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
300 of the multiset ordering;
302 * directory HOL/Real: a construction of the reals using Dedekind cuts
303 (not included by default);
305 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
307 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
308 programs, i.e. different program variables may have different types.
310 * calling (stac rew i) now fails if "rew" has no effect on the goal
311 [previously, this check worked only if the rewrite rule was unconditional]
312 Now rew can involve either definitions or equalities (either == or =).
317 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
318 only the theorems proved on ZF.ML;
320 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
321 It and 'sym RS equals0D' are now in the default claset, giving automatic
322 disjointness reasoning but breaking a few old proofs.
324 * ZF/Update: new theory of function updates
325 with default rewrite rule f(x:=y) ` z = if(z=x, y, f`z)
326 may also be iterated as in f(a:=b,c:=d,...);
328 * in let x=t in u(x), neither t nor u(x) has to be an FOL term.
330 * calling (stac rew i) now fails if "rew" has no effect on the goal
331 [previously, this check worked only if the rewrite rule was unconditional]
332 Now rew can involve either definitions or equalities (either == or =).
334 * case_tac provided for compatibility with HOL
335 (like the old excluded_middle_tac, but with subgoals swapped)
338 *** Internal programming interfaces ***
340 * Pure: several new basic modules made available for general use, see
341 also src/Pure/README;
343 * improved the theory data mechanism to support encapsulation (data
344 kind name replaced by private Object.kind, acting as authorization
345 key); new type-safe user interface via functor TheoryDataFun; generic
346 print_data function becomes basically useless;
348 * removed global_names compatibility flag -- all theory declarations
349 are qualified by default;
351 * module Pure/Syntax now offers quote / antiquote translation
352 functions (useful for Hoare logic etc. with implicit dependencies);
353 see HOL/ex/Antiquote for an example use;
355 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
358 * new tactical CHANGED_GOAL for checking that a tactic modifies a
361 * Display.print_goals function moved to Locale.print_goals;
363 * standard print function for goals supports current_goals_markers
364 variable for marking begin of proof, end of proof, start of goal; the
365 default is ("", "", ""); setting current_goals_markers := ("<proof>",
366 "</proof>", "<goal>") causes SGML like tagged proof state printing,
371 New in Isabelle98 (January 1998)
372 --------------------------------
374 *** Overview of INCOMPATIBILITIES (see below for more details) ***
376 * changed lexical syntax of terms / types: dots made part of long
377 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
379 * simpset (and claset) reference variable replaced by functions
380 simpset / simpset_ref;
382 * no longer supports theory aliases (via merge) and non-trivial
383 implicit merge of thms' signatures;
385 * most internal names of constants changed due to qualified names;
387 * changed Pure/Sequence interface (see Pure/seq.ML);
390 *** General Changes ***
392 * hierachically structured name spaces (for consts, types, axms, thms
393 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
394 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
395 isatool fixdots ensures space after dots (e.g. "%x. x"); set
396 long_names for fully qualified output names; NOTE: ML programs
397 (special tactics, packages etc.) referring to internal names may have
398 to be adapted to cope with fully qualified names; in case of severe
399 backward campatibility problems try setting 'global_names' at compile
400 time to have enrything declared within a flat name space; one may also
401 fine tune name declarations in theories via the 'global' and 'local'
404 * reimplemented the implicit simpset and claset using the new anytype
405 data filed in signatures; references simpset:simpset ref etc. are
406 replaced by functions simpset:unit->simpset and
407 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
408 to patch your ML files accordingly;
410 * HTML output now includes theory graph data for display with Java
411 applet or isatool browser; data generated automatically via isatool
412 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
414 * defs may now be conditional; improved rewrite_goals_tac to handle
415 conditional equations;
417 * defs now admits additional type arguments, using TYPE('a) syntax;
419 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
420 creates a new theory node; implicit merge of thms' signatures is
421 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
422 transfer:theory->thm->thm in (rare) cases;
424 * improved handling of draft signatures / theories; draft thms (and
425 ctyps, cterms) are automatically promoted to real ones;
427 * slightly changed interfaces for oracles: admit many per theory, named
428 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
430 * print_goals: optional output of const types (set show_consts and
433 * improved output of warnings (###) and errors (***);
435 * subgoal_tac displays a warning if the new subgoal has type variables;
437 * removed old README and Makefiles;
439 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
441 * removed obsolete init_pps and init_database;
443 * deleted the obsolete tactical STATE, which was declared by
444 fun STATE tacfun st = tacfun st st;
446 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
447 (which abbreviates $HOME);
449 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
450 use isatool fixseq to adapt your ML programs (this works for fully
451 qualified references to the Sequence structure only!);
453 * use_thy no longer requires writable current directory; it always
454 reloads .ML *and* .thy file, if either one is out of date;
457 *** Classical Reasoner ***
459 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
460 tactics that use classical reasoning to simplify a subgoal without
461 splitting it into several subgoals;
463 * Safe_tac: like safe_tac but uses the default claset;
468 * added simplification meta rules:
469 (asm_)(full_)simplify: simpset -> thm -> thm;
471 * simplifier.ML no longer part of Pure -- has to be loaded by object
474 * added prems argument to simplification procedures;
476 * HOL, FOL, ZF: added infix function `addsplits':
477 instead of `<simpset> setloop (split_tac <thms>)'
478 you can simply write `<simpset> addsplits <thms>'
483 * TYPE('a) syntax for type reflection terms;
485 * no longer handles consts with name "" -- declare as 'syntax' instead;
487 * pretty printer: changed order of mixfix annotation preference (again!);
489 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
494 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
495 with `addloop' of the simplifier to faciliate case splitting in premises.
497 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
499 * HOL/Auth: new protocol proofs including some for the Internet
502 * HOL/Map: new theory of `maps' a la VDM;
504 * HOL/simplifier: simplification procedures nat_cancel_sums for
505 cancelling out common nat summands from =, <, <= (in)equalities, or
506 differences; simplification procedures nat_cancel_factor for
507 cancelling common factor from =, <, <= (in)equalities over natural
508 sums; nat_cancel contains both kinds of procedures, it is installed by
509 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
511 * HOL/simplifier: terms of the form
512 `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)' (or t=x)
514 `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
515 and those of the form
516 `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)' (or t=x)
518 `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
521 Each datatype `t' now comes with a theorem `split_t_case' of the form
523 P(t_case f1 ... fn x) =
524 ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
526 (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
529 and a theorem `split_t_case_asm' of the form
531 P(t_case f1 ... fn x) =
532 ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
534 (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
536 which can be added to a simpset via `addsplits'. The existing theorems
537 expand_list_case and expand_option_case have been renamed to
538 split_list_case and split_option_case.
541 - `pred n' is automatically converted to `n-1'.
542 Users are strongly encouraged not to use `pred' any longer,
543 because it will disappear altogether at some point.
544 - Users are strongly encouraged to write "0 < n" rather than
545 "n ~= 0". Theorems and proof tools have been modified towards this
549 the function "set_of_list" has been renamed "set" (and its theorems too);
550 the function "nth" now takes its arguments in the reverse order and
551 has acquired the infix notation "!" as in "xs!n".
553 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
555 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
556 specialist theorems (like UN1_I) are gone. Similarly for (INT x.B x);
558 * HOL/record: extensible records with schematic structural subtyping
559 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
560 still lacks various theorems and concrete record syntax;
565 * removed "axioms" and "generated by" sections;
567 * replaced "ops" section by extended "consts" section, which is capable of
568 handling the continuous function space "->" directly;
571 . proves theorems immediately and stores them in the theory,
572 . creates hierachical name space,
573 . now uses normal mixfix annotations (instead of cinfix...),
574 . minor changes to some names and values (for consistency),
575 . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
576 . separator between mutual domain defs: changed "," to "and",
577 . improved handling of sort constraints; now they have to
578 appear on the left-hand side of the equations only;
580 * fixed LAM <x,y,zs>.b syntax;
582 * added extended adm_tac to simplifier in HOLCF -- can now discharge
583 adm (%x. P (t x)), where P is chainfinite and t continuous;
588 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
589 with `addloop' of the simplifier to faciliate case splitting in premises.
591 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
592 in HOL, they strip ALL and --> from proved theorems;
596 New in Isabelle94-8 (May 1997)
597 ------------------------------
599 *** General Changes ***
601 * new utilities to build / run / maintain Isabelle etc. (in parts
602 still somewhat experimental); old Makefiles etc. still functional;
604 * new 'Isabelle System Manual';
606 * INSTALL text, together with ./configure and ./build scripts;
608 * reimplemented type inference for greater efficiency, better error
609 messages and clean internal interface;
611 * prlim command for dealing with lots of subgoals (an easier way of
612 setting goals_limit);
617 * supports alternative (named) syntax tables (parser and pretty
618 printer); internal interface is provided by add_modesyntax(_i);
620 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
621 be used in conjunction with the Isabelle symbol font; uses the
622 "symbols" syntax table;
624 * added token_translation interface (may translate name tokens in
625 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
626 the current print_mode); IMPORTANT: user print translation functions
627 are responsible for marking newly introduced bounds
628 (Syntax.mark_boundT);
630 * token translations for modes "xterm" and "xterm_color" that display
631 names in bold, underline etc. or colors (which requires a color
634 * infixes may now be declared with names independent of their syntax;
636 * added typed_print_translation (like print_translation, but may
637 access type of constant);
640 *** Classical Reasoner ***
642 Blast_tac: a new tactic! It is often more powerful than fast_tac, but has
643 some limitations. Blast_tac...
644 + ignores addss, addbefore, addafter; this restriction is intrinsic
645 + ignores elimination rules that don't have the correct format
646 (the conclusion MUST be a formula variable)
647 + ignores types, which can make HOL proofs fail
648 + rules must not require higher-order unification, e.g. apply_type in ZF
649 [message "Function Var's argument not a bound variable" relates to this]
650 + its proof strategy is more general but can actually be slower
652 * substitution with equality assumptions no longer permutes other
655 * minor changes in semantics of addafter (now called addaltern); renamed
656 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
657 (and access functions for it);
659 * improved combination of classical reasoner and simplifier:
660 + functions for handling clasimpsets
661 + improvement of addss: now the simplifier is called _after_ the
663 + safe variant of addss called addSss: uses safe simplifications
664 _during_ the safe steps. It is more complete as it allows multiple
665 instantiations of unknowns (e.g. with slow_tac).
669 * added interface for simplification procedures (functions that
670 produce *proven* rewrite rules on the fly, depending on current
673 * ordering on terms as parameter (used for ordered rewriting);
675 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
677 * the solver is now split into a safe and an unsafe part.
678 This should be invisible for the normal user, except that the
679 functions setsolver and addsolver have been renamed to setSolver and
680 addSolver; added safe_asm_full_simp_tac;
685 * a generic induction tactic `induct_tac' which works for all datatypes and
688 * a generic case distinction tactic `exhaust_tac' which works for all
689 datatypes and also for type `nat';
691 * each datatype comes with a function `size';
693 * patterns in case expressions allow tuple patterns as arguments to
694 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
696 * primrec now also works with type nat;
698 * recdef: a new declaration form, allows general recursive functions to be
699 defined in theory files. See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
701 * the constant for negation has been renamed from "not" to "Not" to
702 harmonize with FOL, ZF, LK, etc.;
704 * HOL/ex/LFilter theory of a corecursive "filter" functional for
707 * HOL/Modelcheck demonstrates invocation of model checker oracle;
709 * HOL/ex/Ring.thy declares cring_simp, which solves equational
710 problems in commutative rings, using axiomatic type classes for + and *;
712 * more examples in HOL/MiniML and HOL/Auth;
714 * more default rewrite rules for quantifiers, union/intersection;
716 * a new constant `arbitrary == @x.False';
718 * HOLCF/IOA replaces old HOL/IOA;
720 * HOLCF changes: derived all rules and arities
721 + axiomatic type classes instead of classes
722 + typedef instead of faking type definitions
723 + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
724 + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
725 + eliminated the types void, one, tr
726 + use unit lift and bool lift (with translations) instead of one and tr
727 + eliminated blift from Lift3.thy (use Def instead of blift)
728 all eliminated rules are derived as theorems --> no visible changes ;
733 * ZF now has Fast_tac, Simp_tac and Auto_tac. Union_iff is a now a default
734 rewrite rule; this may affect some proofs. eq_cs is gone but can be put back
735 as ZF_cs addSIs [equalityI];
739 New in Isabelle94-7 (November 96)
740 ---------------------------------
742 * allowing negative levels (as offsets) in prlev and choplev;
744 * super-linear speedup for large simplifications;
746 * FOL, ZF and HOL now use miniscoping: rewriting pushes
747 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
748 FAIL); can suppress it using the command Delsimps (ex_simps @
749 all_simps); De Morgan laws are also now included, by default;
751 * improved printing of ==> : ~:
753 * new object-logic "Sequents" adds linear logic, while replacing LK
754 and Modal (thanks to Sara Kalvala);
756 * HOL/Auth: correctness proofs for authentication protocols;
758 * HOL: new auto_tac combines rewriting and classical reasoning (many
759 examples on HOL/Auth);
761 * HOL: new command AddIffs for declaring theorems of the form P=Q to
762 the rewriter and classical reasoner simultaneously;
764 * function uresult no longer returns theorems in "standard" format;
765 regain previous version by: val uresult = standard o uresult;
772 * oracles -- these establish an interface between Isabelle and trusted
773 external reasoners, which may deliver results as theorems;
775 * proof objects (in particular record all uses of oracles);
777 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
779 * "constdefs" section in theory files;
781 * "primrec" section (HOL) no longer requires names;
783 * internal type "tactic" now simply "thm -> thm Sequence.seq";
790 * reduced space requirements;
792 * automatic HTML generation from theories;
794 * theory files no longer require "..." (quotes) around most types;
796 * new examples, including two proofs of the Church-Rosser theorem;
798 * non-curried (1994) version of HOL is no longer distributed;
805 * greatly reduced space requirements;
807 * theory files (.thy) no longer require \...\ escapes at line breaks;
809 * searchable theorem database (see the section "Retrieving theorems" on
810 page 8 of the Reference Manual);
812 * new examples, including Grabczewski's monumental case study of the
815 * The previous version of HOL renamed to Old_HOL;
817 * The new version of HOL (previously called CHOL) uses a curried syntax
818 for functions. Application looks like f a b instead of f(a,b);
820 * Mutually recursive inductive definitions finally work in HOL;
822 * In ZF, pattern-matching on tuples is now available in all abstractions and
823 translates to the operator "split";
830 * new infix operator, addss, allowing the classical reasoner to
831 perform simplification at each step of its search. Example:
832 fast_tac (cs addss ss)
834 * a new logic, CHOL, the same as HOL, but with a curried syntax
835 for functions. Application looks like f a b instead of f(a,b). Also pairs
836 look like (a,b) instead of <a,b>;
838 * PLEASE NOTE: CHOL will eventually replace HOL!
840 * In CHOL, pattern-matching on tuples is now available in all abstractions.
841 It translates to the operator "split". A new theory of integers is available;
843 * In ZF, integer numerals now denote two's-complement binary integers.
844 Arithmetic operations can be performed by rewriting. See ZF/ex/Bin.ML;
846 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
847 of the Axiom of Choice;
854 * Significantly faster resolution;
856 * the different sections in a .thy file can now be mixed and repeated
859 * Database of theorems for FOL, HOL and ZF. New
860 commands including qed, qed_goal and bind_thm store theorems in the database.
862 * Simple database queries: return a named theorem (get_thm) or all theorems of
863 a given theory (thms_of), or find out what theory a theorem was proved in
866 * Bugs fixed in the inductive definition and datatype packages;
868 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
869 and HOL_dup_cs obsolete;
871 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
874 * Simpler definition of function space in ZF;
876 * new results about cardinal and ordinal arithmetic in ZF;
878 * 'subtype' facility in HOL for introducing new types as subsets of existing