NEWS
author wenzelm
Fri Mar 24 13:48:01 2000 +0100 (2000-03-24)
changeset 8566 30261b1917b5
parent 8534 fdbabfbc3829
child 8570 63d4f3ea2e70
permissions -rw-r--r--
usedir -D: update styles;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in this Isabelle version
     6 ----------------------------
     7 
     8 *** Overview of INCOMPATIBILITIES (see below for more details) ***
     9 
    10 * HOL: the constant for f``x is now "image" rather than "op ``".
    11 
    12 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
    13 
    14 * ML: PureThy.add_thms/add_axioms/add_defs return theorems as well;
    15 
    16 
    17 *** Document preparation ***
    18 
    19 * isatool mkdir provides easy setup of Isabelle session directories,
    20 including proper document sources;
    21 
    22 * generated LaTeX sources are now deleted after successful run
    23 (isatool document -c); may retain a copy somewhere else via -D option
    24 of isatool usedir;
    25 
    26 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
    27 style files, achieving self-contained LaTeX sources;
    28 
    29 * old-style theories now produce (crude) LaTeX output as well;
    30 
    31 
    32 *** Isar ***
    33 
    34 * Pure now provides its own version of intro/elim/dest attributes;
    35 useful for building new logics, but beware of confusion with the
    36 Provers/classical ones;
    37 
    38 * Pure: new 'obtain' language element supports generalized elimination
    39 proofs;
    40 
    41 * Pure: scalable support for case-analysis type proofs: new 'case'
    42 language element refers to local contexts symbolically, as produced by
    43 certain proof methods; internally, case names are attached to theorems
    44 as "tags";
    45 
    46 * Provers: splitter support (via 'split' attribute and 'simp' method
    47 modifier); 'simp' method: 'only:' modifier removes loopers as well
    48 (including splits);
    49 
    50 * HOL: new proof method 'cases' and improved version of 'induct' now
    51 support named cases; major packages (inductive, datatype, primrec,
    52 recdef) support case names and properly name parameters;
    53 
    54 * HOL: removed 'case_split' thm binding, should use 'cases' proof
    55 method anyway;
    56 
    57 * names of theorems etc. may be natural numbers as well;
    58 
    59 * Provers: intro/elim/dest attributes: changed ! / !! flags to ? / ??;
    60 
    61 * 'pr' command: optional goals_limit argument;
    62 
    63 * diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
    64 additional print modes to be specified; e.g. "pr(latex)" will print
    65 proof state according to the Isabelle LaTeX style;
    66 
    67 * improved support for emulating tactic scripts, including proof
    68 methods 'tactic', 'res_inst_tac' etc., 'subgoal_tac', and 'case_tac' /
    69 'induct_tac' (for HOL datatypes);
    70 
    71 
    72 
    73 *** HOL ***
    74 
    75 * HOL/Algebra: new theory of rings and univariate polynomials, by
    76 Clemens Ballarin;
    77 
    78 * HOL/record: fixed select-update simplification procedure to handle
    79 extended records as well; admit "r" as field name;
    80 
    81 * HOL/ex: new theory Factorization proving the Fundamental Theorem of
    82 Arithmetic, by Thomas M Rasmussen;
    83 
    84 * new version of "case_tac" subsumes both boolean case split and
    85 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
    86 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
    87 
    88 
    89 *** General ***
    90 
    91 * compression of ML heaps images may now be controlled via -c option
    92 of isabelle and isatool usedir (currently only observed by Poly/ML);
    93 
    94 * ML: new combinators |>> and |>>> for incremental transformations
    95 with secondary results (e.g. certain theory extensions):
    96 
    97 
    98 
    99 New in Isabelle99 (October 1999)
   100 --------------------------------
   101 
   102 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   103 
   104 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   105 are no longer simplified.  (This allows the simplifier to unfold recursive
   106 functional programs.)  To restore the old behaviour, declare
   107 
   108     Delcongs [if_weak_cong];
   109 
   110 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   111 complement;
   112 
   113 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   114 
   115 * HOL/datatype: mutual_induct_tac no longer exists --
   116   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   117 
   118 * HOL/typedef: fixed type inference for representing set; type
   119 arguments now have to occur explicitly on the rhs as type constraints;
   120 
   121 * ZF: The con_defs part of an inductive definition may no longer refer
   122 to constants declared in the same theory;
   123 
   124 * HOL, ZF: the function mk_cases, generated by the inductive
   125 definition package, has lost an argument.  To simplify its result, it
   126 uses the default simpset instead of a supplied list of theorems.
   127 
   128 * HOL/List: the constructors of type list are now Nil and Cons;
   129 
   130 * Simplifier: the type of the infix ML functions
   131 	setSSolver addSSolver setSolver addSolver
   132 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   133 for packaging solvers. A solver is created via
   134 	mk_solver: string -> (thm list -> int -> tactic) -> solver
   135 where the string argument is only a comment.
   136 
   137 
   138 *** Proof tools ***
   139 
   140 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   141 decision procedure for linear arithmetic. Currently it is used for
   142 types `nat', `int', and `real' in HOL (see below); it can, should and
   143 will be instantiated for other types and logics as well.
   144 
   145 * The simplifier now accepts rewrite rules with flexible heads, eg
   146      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   147   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   148   matching.
   149 
   150 
   151 *** General ***
   152 
   153 * New Isabelle/Isar subsystem provides an alternative to traditional
   154 tactical theorem proving; together with the ProofGeneral/isar user
   155 interface it offers an interactive environment for developing human
   156 readable proof documents (Isar == Intelligible semi-automated
   157 reasoning); for further information see isatool doc isar-ref,
   158 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   159 
   160 * improved presentation of theories: better HTML markup (including
   161 colors), graph views in several sizes; isatool usedir now provides a
   162 proper interface for user theories (via -P option); actual document
   163 preparation based on (PDF)LaTeX is available as well (for new-style
   164 theories only); see isatool doc system for more information;
   165 
   166 * native support for Proof General, both for classic Isabelle and
   167 Isabelle/Isar;
   168 
   169 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   170 using the graph browser tool;
   171 
   172 * Isabelle manuals now also available as PDF;
   173 
   174 * theory loader rewritten from scratch (may not be fully
   175 bug-compatible); old loadpath variable has been replaced by show_path,
   176 add_path, del_path, reset_path functions; new operations such as
   177 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   178 isatool doc ref);
   179 
   180 * improved isatool install: option -k creates KDE application icon,
   181 option -p DIR installs standalone binaries;
   182 
   183 * added ML_PLATFORM setting (useful for cross-platform installations);
   184 more robust handling of platform specific ML images for SML/NJ;
   185 
   186 * the settings environment is now statically scoped, i.e. it is never
   187 created again in sub-processes invoked from isabelle, isatool, or
   188 Isabelle;
   189 
   190 * path element specification '~~' refers to '$ISABELLE_HOME';
   191 
   192 * in locales, the "assumes" and "defines" parts may be omitted if
   193 empty;
   194 
   195 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   196 long arrows);
   197 
   198 * new print_mode "HTML";
   199 
   200 * new flag show_tags controls display of tags of theorems (which are
   201 basically just comments that may be attached by some tools);
   202 
   203 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   204 mode and goal output format:
   205 
   206 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   207 244c244
   208 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   209 ---
   210 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   211 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   212 181c181
   213 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   214 ---
   215 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   216 
   217 * function bind_thms stores lists of theorems (cf. bind_thm);
   218 
   219 * new shorthand tactics ftac, eatac, datac, fatac;
   220 
   221 * qed (and friends) now accept "" as result name; in that case the
   222 theorem is not stored, but proper checks and presentation of the
   223 result still apply;
   224 
   225 * theorem database now also indexes constants "Trueprop", "all",
   226 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   227 
   228 
   229 *** HOL ***
   230 
   231 ** HOL arithmetic **
   232 
   233 * There are now decision procedures for linear arithmetic over nat and
   234 int:
   235 
   236 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   237 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   238 are treated as atomic; subformulae not involving type `nat' or `int'
   239 are ignored; quantified subformulae are ignored unless they are
   240 positive universal or negative existential. The tactic has to be
   241 invoked by hand and can be a little bit slow. In particular, the
   242 running time is exponential in the number of occurrences of `min' and
   243 `max', and `-' on `nat'.
   244 
   245 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   246 (negated) (in)equalities among the premises and the conclusion into
   247 account (i.e. no compound formulae) and does not know about `min' and
   248 `max', and `-' on `nat'. It is fast and is used automatically by the
   249 simplifier.
   250 
   251 NB: At the moment, these decision procedures do not cope with mixed
   252 nat/int formulae where the two parts interact, such as `m < n ==>
   253 int(m) < int(n)'.
   254 
   255 * HOL/Numeral provides a generic theory of numerals (encoded
   256 efficiently as bit strings); setup for types nat/int/real is in place;
   257 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   258 int, existing theories and proof scripts may require a few additional
   259 type constraints;
   260 
   261 * integer division and remainder can now be performed on constant
   262 arguments;
   263 
   264 * many properties of integer multiplication, division and remainder
   265 are now available;
   266 
   267 * An interface to the Stanford Validity Checker (SVC) is available through the
   268 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   269 are proved automatically.  SVC must be installed separately, and its results
   270 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   271 invocation of the underlying oracle).  For SVC see
   272   http://verify.stanford.edu/SVC
   273 
   274 * IsaMakefile: the HOL-Real target now builds an actual image;
   275 
   276 
   277 ** HOL misc **
   278 
   279 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   280 (in Isabelle/Isar) -- by Gertrud Bauer;
   281 
   282 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   283 analysis for assembly languages with subtypes;
   284 
   285 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   286 -- avoids syntactic ambiguities and treats state, transition, and
   287 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   288 changed syntax and (many) tactics;
   289 
   290 * HOL/inductive: Now also handles more general introduction rules such
   291   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   292   theorems are now maintained within the theory (maintained via the
   293   "mono" attribute);
   294 
   295 * HOL/datatype: Now also handles arbitrarily branching datatypes
   296   (using function types) such as
   297 
   298   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   299 
   300 * HOL/record: record_simproc (part of the default simpset) takes care
   301 of selectors applied to updated records; record_split_tac is no longer
   302 part of the default claset; update_defs may now be removed from the
   303 simpset in many cases; COMPATIBILITY: old behavior achieved by
   304 
   305   claset_ref () := claset() addSWrapper record_split_wrapper;
   306   Delsimprocs [record_simproc]
   307 
   308 * HOL/typedef: fixed type inference for representing set; type
   309 arguments now have to occur explicitly on the rhs as type constraints;
   310 
   311 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   312 names rather than an ML expression;
   313 
   314 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   315 supplied later.  Program schemes can be defined, such as
   316     "While B C s = (if B s then While B C (C s) else s)"
   317 where the well-founded relation can be chosen after B and C have been given.
   318 
   319 * HOL/List: the constructors of type list are now Nil and Cons;
   320 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   321 course, ML tools referring to List.list.op # etc. have to be adapted;
   322 
   323 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   324 disabled by default; run isabelle with option -m HOL to get back to
   325 the original Gordon/HOL-style output;
   326 
   327 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   328 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   329 
   330 * HOL basic syntax simplified (more orthogonal): all variants of
   331 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   332 Eps operator is provided as well: "SOME x. P[x]";
   333 
   334 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   335 
   336 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   337 thus available for user theories;
   338 
   339 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   340 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   341 time;
   342 
   343 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   344 several times and then mp;
   345 
   346 
   347 *** LK ***
   348 
   349 * the notation <<...>> is now available as a notation for sequences of
   350 formulas;
   351 
   352 * the simplifier is now installed
   353 
   354 * the axiom system has been generalized (thanks to Soren Heilmann) 
   355 
   356 * the classical reasoner now has a default rule database
   357 
   358 
   359 *** ZF ***
   360 
   361 * new primrec section allows primitive recursive functions to be given
   362 directly (as in HOL) over datatypes and the natural numbers;
   363 
   364 * new tactics induct_tac and exhaust_tac for induction (or case
   365 analysis) over datatypes and the natural numbers;
   366 
   367 * the datatype declaration of type T now defines the recursor T_rec;
   368 
   369 * simplification automatically does freeness reasoning for datatype
   370 constructors;
   371 
   372 * automatic type-inference, with AddTCs command to insert new
   373 type-checking rules;
   374 
   375 * datatype introduction rules are now added as Safe Introduction rules
   376 to the claset;
   377 
   378 * the syntax "if P then x else y" is now available in addition to
   379 if(P,x,y);
   380 
   381 
   382 *** Internal programming interfaces ***
   383 
   384 * tuned simplifier trace output; new flag debug_simp;
   385 
   386 * structures Vartab / Termtab (instances of TableFun) offer efficient
   387 tables indexed by indexname_ord / term_ord (compatible with aconv);
   388 
   389 * AxClass.axclass_tac lost the theory argument;
   390 
   391 * tuned current_goals_markers semantics: begin / end goal avoids
   392 printing empty lines;
   393 
   394 * removed prs and prs_fn hook, which was broken because it did not
   395 include \n in its semantics, forcing writeln to add one
   396 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   397 string -> unit if you really want to output text without newline;
   398 
   399 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   400 plain output, interface builders may have to enable 'isabelle_font'
   401 mode to get Isabelle font glyphs as before;
   402 
   403 * refined token_translation interface; INCOMPATIBILITY: output length
   404 now of type real instead of int;
   405 
   406 * theory loader actions may be traced via new ThyInfo.add_hook
   407 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   408 your own database of information attached to *whole* theories -- as
   409 opposed to intra-theory data slots offered via TheoryDataFun;
   410 
   411 * proper handling of dangling sort hypotheses (at last!);
   412 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   413 extra sort hypotheses that can be witnessed from the type signature;
   414 the force_strip_shyps flag is gone, any remaining shyps are simply
   415 left in the theorem (with a warning issued by strip_shyps_warning);
   416 
   417 
   418 
   419 New in Isabelle98-1 (October 1998)
   420 ----------------------------------
   421 
   422 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   423 
   424 * several changes of automated proof tools;
   425 
   426 * HOL: major changes to the inductive and datatype packages, including
   427 some minor incompatibilities of theory syntax;
   428 
   429 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   430 called `inj_on';
   431 
   432 * HOL: removed duplicate thms in Arith:
   433   less_imp_add_less  should be replaced by  trans_less_add1
   434   le_imp_add_le      should be replaced by  trans_le_add1
   435 
   436 * HOL: unary minus is now overloaded (new type constraints may be
   437 required);
   438 
   439 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   440 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   441 now taken as an integer constant.
   442 
   443 * Pure: ML function 'theory_of' renamed to 'theory';
   444 
   445 
   446 *** Proof tools ***
   447 
   448 * Simplifier:
   449   1. Asm_full_simp_tac is now more aggressive.
   450      1. It will sometimes reorient premises if that increases their power to
   451         simplify.
   452      2. It does no longer proceed strictly from left to right but may also
   453         rotate premises to achieve further simplification.
   454      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   455      old Asm_full_simp_tac in that it does not rotate premises.
   456   2. The simplifier now knows a little bit about nat-arithmetic.
   457 
   458 * Classical reasoner: wrapper mechanism for the classical reasoner now
   459 allows for selected deletion of wrappers, by introduction of names for
   460 wrapper functionals.  This implies that addbefore, addSbefore,
   461 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   462 and that adding two tactics with the same name overwrites the first
   463 one (emitting a warning).
   464   type wrapper = (int -> tactic) -> (int -> tactic)
   465   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   466   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   467   delWrapper, delSWrapper: claset *  string            -> claset
   468   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   469 
   470 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   471 semantics; addbefore now affects only the unsafe part of step_tac
   472 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   473 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   474 by Force_tac;
   475 
   476 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   477 compWrapper; added safe wrapper (and access functions for it);
   478 
   479 * HOL/split_all_tac is now much faster and fails if there is nothing
   480 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   481 and the names of the automatically generated variables have changed.
   482 split_all_tac has moved within claset() from unsafe wrappers to safe
   483 wrappers, which means that !!-bound variables are split much more
   484 aggressively, and safe_tac and clarify_tac now split such variables.
   485 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   486 Note: the same holds for record_split_tac, which does the job of
   487 split_all_tac for record fields.
   488 
   489 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   490 permanently to the default simpset using Addsplits just like
   491 Addsimps. They can be removed via Delsplits just like
   492 Delsimps. Lower-case versions are also available.
   493 
   494 * HOL/Simplifier: The rule split_if is now part of the default
   495 simpset. This means that the simplifier will eliminate all occurrences
   496 of if-then-else in the conclusion of a goal. To prevent this, you can
   497 either remove split_if completely from the default simpset by
   498 `Delsplits [split_if]' or remove it in a specific call of the
   499 simplifier using `... delsplits [split_if]'.  You can also add/delete
   500 other case splitting rules to/from the default simpset: every datatype
   501 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   502 t is the name of the datatype).
   503 
   504 * Classical reasoner / Simplifier combination: new force_tac (and
   505 derivatives Force_tac, force) combines rewriting and classical
   506 reasoning (and whatever other tools) similarly to auto_tac, but is
   507 aimed to solve the given subgoal completely.
   508 
   509 
   510 *** General ***
   511 
   512 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   513 and `goalw': the theory is no longer needed as an explicit argument -
   514 the current theory context is used; assumptions are no longer returned
   515 at the ML-level unless one of them starts with ==> or !!; it is
   516 recommended to convert to these new commands using isatool fixgoal
   517 (backup your sources first!);
   518 
   519 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   520 the current theory context, and 'theory' to lookup stored theories;
   521 
   522 * new theory section 'locale' for declaring constants, assumptions and
   523 definitions that have local scope;
   524 
   525 * new theory section 'nonterminals' for purely syntactic types;
   526 
   527 * new theory section 'setup' for generic ML setup functions
   528 (e.g. package initialization);
   529 
   530 * the distribution now includes Isabelle icons: see
   531 lib/logo/isabelle-{small,tiny}.xpm;
   532 
   533 * isatool install - install binaries with absolute references to
   534 ISABELLE_HOME/bin;
   535 
   536 * isatool logo -- create instances of the Isabelle logo (as EPS);
   537 
   538 * print mode 'emacs' reserved for Isamode;
   539 
   540 * support multiple print (ast) translations per constant name;
   541 
   542 * theorems involving oracles are now printed with a suffixed [!];
   543 
   544 
   545 *** HOL ***
   546 
   547 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   548 
   549 * HOL/inductive package reorganized and improved: now supports mutual
   550 definitions such as
   551 
   552   inductive EVEN ODD
   553     intrs
   554       null "0 : EVEN"
   555       oddI "n : EVEN ==> Suc n : ODD"
   556       evenI "n : ODD ==> Suc n : EVEN"
   557 
   558 new theorem list "elims" contains an elimination rule for each of the
   559 recursive sets; inductive definitions now handle disjunctive premises
   560 correctly (also ZF);
   561 
   562 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   563 "mutual_induct" no longer exists - the induction rule is always
   564 contained in "induct";
   565 
   566 
   567 * HOL/datatype package re-implemented and greatly improved: now
   568 supports mutually recursive datatypes such as
   569 
   570   datatype
   571     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   572             | SUM ('a aexp) ('a aexp)
   573             | DIFF ('a aexp) ('a aexp)
   574             | NUM 'a
   575   and
   576     'a bexp = LESS ('a aexp) ('a aexp)
   577             | AND ('a bexp) ('a bexp)
   578             | OR ('a bexp) ('a bexp)
   579 
   580 as well as indirectly recursive datatypes such as
   581 
   582   datatype
   583     ('a, 'b) term = Var 'a
   584                   | App 'b ((('a, 'b) term) list)
   585 
   586 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   587 induction on mutually / indirectly recursive datatypes.
   588 
   589 Primrec equations are now stored in theory and can be accessed via
   590 <function_name>.simps.
   591 
   592 INCOMPATIBILITIES:
   593 
   594   - Theories using datatypes must now have theory Datatype as an
   595     ancestor.
   596   - The specific <typename>.induct_tac no longer exists - use the
   597     generic induct_tac instead.
   598   - natE has been renamed to nat.exhaust - use exhaust_tac
   599     instead of res_inst_tac ... natE. Note that the variable
   600     names in nat.exhaust differ from the names in natE, this
   601     may cause some "fragile" proofs to fail.
   602   - The theorems split_<typename>_case and split_<typename>_case_asm
   603     have been renamed to <typename>.split and <typename>.split_asm.
   604   - Since default sorts of type variables are now handled correctly,
   605     some datatype definitions may have to be annotated with explicit
   606     sort constraints.
   607   - Primrec definitions no longer require function name and type
   608     of recursive argument.
   609 
   610 Consider using isatool fixdatatype to adapt your theories and proof
   611 scripts to the new package (backup your sources first!).
   612 
   613 
   614 * HOL/record package: considerably improved implementation; now
   615 includes concrete syntax for record types, terms, updates; theorems
   616 for surjective pairing and splitting !!-bound record variables; proof
   617 support is as follows:
   618 
   619   1) standard conversions (selectors or updates applied to record
   620 constructor terms) are part of the standard simpset;
   621 
   622   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   623 made part of standard simpset and claset via addIffs;
   624 
   625   3) a tactic for record field splitting (record_split_tac) is part of
   626 the standard claset (addSWrapper);
   627 
   628 To get a better idea about these rules you may retrieve them via
   629 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   630 the name of your record type.
   631 
   632 The split tactic 3) conceptually simplifies by the following rule:
   633 
   634   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   635 
   636 Thus any record variable that is bound by meta-all will automatically
   637 blow up into some record constructor term, consequently the
   638 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   639 solve record problems automatically.
   640 
   641 
   642 * reorganized the main HOL image: HOL/Integ and String loaded by
   643 default; theory Main includes everything;
   644 
   645 * automatic simplification of integer sums and comparisons, using cancellation;
   646 
   647 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   648 
   649 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   650 
   651 * many new identities for unions, intersections, set difference, etc.;
   652 
   653 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   654 called split_if, split_split, split_sum_case and split_nat_case (to go
   655 with add/delsplits);
   656 
   657 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   658 (?x::unit) = (); this is made part of the default simpset, which COULD
   659 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   660 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   661 unit_abs_eta_conv is added in order to counter the effect of
   662 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   663 %u.f();
   664 
   665 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   666 makes more sense);
   667 
   668 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   669   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   670   disjointness reasoning but breaking a few old proofs.
   671 
   672 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   673 to 'converse' from 'inverse' (for compatibility with ZF and some
   674 literature);
   675 
   676 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   677 the well-founded relation;
   678 
   679 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   680     Compl A.  The "Compl" syntax remains available as input syntax for this
   681     release ONLY.
   682 
   683 * HOL/Update: new theory of function updates:
   684     f(a:=b) == %x. if x=a then b else f x
   685 may also be iterated as in f(a:=b,c:=d,...);
   686 
   687 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   688 
   689 * HOL/List:
   690   - new function list_update written xs[i:=v] that updates the i-th
   691     list position. May also be iterated as in xs[i:=a,j:=b,...].
   692   - new function `upt' written [i..j(] which generates the list
   693     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   694     bound write [i..j], which is a shorthand for [i..j+1(].
   695   - new lexicographic orderings and corresponding wellfoundedness theorems.
   696 
   697 * HOL/Arith:
   698   - removed 'pred' (predecessor) function;
   699   - generalized some theorems about n-1;
   700   - many new laws about "div" and "mod";
   701   - new laws about greatest common divisors (see theory ex/Primes);
   702 
   703 * HOL/Relation: renamed the relational operator r^-1 "converse"
   704 instead of "inverse";
   705 
   706 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   707   of the multiset ordering;
   708 
   709 * directory HOL/Real: a construction of the reals using Dedekind cuts
   710   (not included by default);
   711 
   712 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   713 
   714 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   715   programs, i.e. different program variables may have different types.
   716 
   717 * calling (stac rew i) now fails if "rew" has no effect on the goal
   718   [previously, this check worked only if the rewrite rule was unconditional]
   719   Now rew can involve either definitions or equalities (either == or =).
   720 
   721 
   722 *** ZF ***
   723 
   724 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   725   only the theorems proved on ZF.ML;
   726 
   727 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   728   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   729   disjointness reasoning but breaking a few old proofs.
   730 
   731 * ZF/Update: new theory of function updates
   732     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   733   may also be iterated as in f(a:=b,c:=d,...);
   734 
   735 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   736 
   737 * calling (stac rew i) now fails if "rew" has no effect on the goal
   738   [previously, this check worked only if the rewrite rule was unconditional]
   739   Now rew can involve either definitions or equalities (either == or =).
   740 
   741 * case_tac provided for compatibility with HOL
   742     (like the old excluded_middle_tac, but with subgoals swapped)
   743 
   744 
   745 *** Internal programming interfaces ***
   746 
   747 * Pure: several new basic modules made available for general use, see
   748 also src/Pure/README;
   749 
   750 * improved the theory data mechanism to support encapsulation (data
   751 kind name replaced by private Object.kind, acting as authorization
   752 key); new type-safe user interface via functor TheoryDataFun; generic
   753 print_data function becomes basically useless;
   754 
   755 * removed global_names compatibility flag -- all theory declarations
   756 are qualified by default;
   757 
   758 * module Pure/Syntax now offers quote / antiquote translation
   759 functions (useful for Hoare logic etc. with implicit dependencies);
   760 see HOL/ex/Antiquote for an example use;
   761 
   762 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   763 cterm -> thm;
   764 
   765 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   766 subgoal;
   767 
   768 * Display.print_goals function moved to Locale.print_goals;
   769 
   770 * standard print function for goals supports current_goals_markers
   771 variable for marking begin of proof, end of proof, start of goal; the
   772 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   773 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   774 for example;
   775 
   776 
   777 
   778 New in Isabelle98 (January 1998)
   779 --------------------------------
   780 
   781 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   782 
   783 * changed lexical syntax of terms / types: dots made part of long
   784 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   785 
   786 * simpset (and claset) reference variable replaced by functions
   787 simpset / simpset_ref;
   788 
   789 * no longer supports theory aliases (via merge) and non-trivial
   790 implicit merge of thms' signatures;
   791 
   792 * most internal names of constants changed due to qualified names;
   793 
   794 * changed Pure/Sequence interface (see Pure/seq.ML);
   795 
   796 
   797 *** General Changes ***
   798 
   799 * hierachically structured name spaces (for consts, types, axms, thms
   800 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   801 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   802 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   803 long_names for fully qualified output names; NOTE: ML programs
   804 (special tactics, packages etc.) referring to internal names may have
   805 to be adapted to cope with fully qualified names; in case of severe
   806 backward campatibility problems try setting 'global_names' at compile
   807 time to have enrything declared within a flat name space; one may also
   808 fine tune name declarations in theories via the 'global' and 'local'
   809 section;
   810 
   811 * reimplemented the implicit simpset and claset using the new anytype
   812 data filed in signatures; references simpset:simpset ref etc. are
   813 replaced by functions simpset:unit->simpset and
   814 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   815 to patch your ML files accordingly;
   816 
   817 * HTML output now includes theory graph data for display with Java
   818 applet or isatool browser; data generated automatically via isatool
   819 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   820 
   821 * defs may now be conditional; improved rewrite_goals_tac to handle
   822 conditional equations;
   823 
   824 * defs now admits additional type arguments, using TYPE('a) syntax;
   825 
   826 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   827 creates a new theory node; implicit merge of thms' signatures is
   828 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   829 transfer:theory->thm->thm in (rare) cases;
   830 
   831 * improved handling of draft signatures / theories; draft thms (and
   832 ctyps, cterms) are automatically promoted to real ones;
   833 
   834 * slightly changed interfaces for oracles: admit many per theory, named
   835 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   836 
   837 * print_goals: optional output of const types (set show_consts and
   838 show_types);
   839 
   840 * improved output of warnings (###) and errors (***);
   841 
   842 * subgoal_tac displays a warning if the new subgoal has type variables;
   843 
   844 * removed old README and Makefiles;
   845 
   846 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   847 
   848 * removed obsolete init_pps and init_database;
   849 
   850 * deleted the obsolete tactical STATE, which was declared by
   851     fun STATE tacfun st = tacfun st st;
   852 
   853 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   854 (which abbreviates $HOME);
   855 
   856 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   857 use isatool fixseq to adapt your ML programs (this works for fully
   858 qualified references to the Sequence structure only!);
   859 
   860 * use_thy no longer requires writable current directory; it always
   861 reloads .ML *and* .thy file, if either one is out of date;
   862 
   863 
   864 *** Classical Reasoner ***
   865 
   866 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   867 tactics that use classical reasoning to simplify a subgoal without
   868 splitting it into several subgoals;
   869 
   870 * Safe_tac: like safe_tac but uses the default claset;
   871 
   872 
   873 *** Simplifier ***
   874 
   875 * added simplification meta rules:
   876     (asm_)(full_)simplify: simpset -> thm -> thm;
   877 
   878 * simplifier.ML no longer part of Pure -- has to be loaded by object
   879 logics (again);
   880 
   881 * added prems argument to simplification procedures;
   882 
   883 * HOL, FOL, ZF: added infix function `addsplits':
   884   instead of `<simpset> setloop (split_tac <thms>)'
   885   you can simply write `<simpset> addsplits <thms>'
   886 
   887 
   888 *** Syntax ***
   889 
   890 * TYPE('a) syntax for type reflection terms;
   891 
   892 * no longer handles consts with name "" -- declare as 'syntax' instead;
   893 
   894 * pretty printer: changed order of mixfix annotation preference (again!);
   895 
   896 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   897 
   898 
   899 *** HOL ***
   900 
   901 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   902   with `addloop' of the simplifier to faciliate case splitting in premises.
   903 
   904 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   905 
   906 * HOL/Auth: new protocol proofs including some for the Internet
   907   protocol TLS;
   908 
   909 * HOL/Map: new theory of `maps' a la VDM;
   910 
   911 * HOL/simplifier: simplification procedures nat_cancel_sums for
   912 cancelling out common nat summands from =, <, <= (in)equalities, or
   913 differences; simplification procedures nat_cancel_factor for
   914 cancelling common factor from =, <, <= (in)equalities over natural
   915 sums; nat_cancel contains both kinds of procedures, it is installed by
   916 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   917 
   918 * HOL/simplifier: terms of the form
   919   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   920   are rewritten to
   921   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   922   and those of the form
   923   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   924   are rewritten to
   925   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   926 
   927 * HOL/datatype
   928   Each datatype `t' now comes with a theorem `split_t_case' of the form
   929 
   930   P(t_case f1 ... fn x) =
   931      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   932         ...
   933        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   934      )
   935 
   936   and a theorem `split_t_case_asm' of the form
   937 
   938   P(t_case f1 ... fn x) =
   939     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   940         ...
   941        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   942      )
   943   which can be added to a simpset via `addsplits'. The existing theorems
   944   expand_list_case and expand_option_case have been renamed to
   945   split_list_case and split_option_case.
   946 
   947 * HOL/Arithmetic:
   948   - `pred n' is automatically converted to `n-1'.
   949     Users are strongly encouraged not to use `pred' any longer,
   950     because it will disappear altogether at some point.
   951   - Users are strongly encouraged to write "0 < n" rather than
   952     "n ~= 0". Theorems and proof tools have been modified towards this
   953     `standard'.
   954 
   955 * HOL/Lists:
   956   the function "set_of_list" has been renamed "set" (and its theorems too);
   957   the function "nth" now takes its arguments in the reverse order and
   958   has acquired the infix notation "!" as in "xs!n".
   959 
   960 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   961 
   962 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   963   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   964 
   965 * HOL/record: extensible records with schematic structural subtyping
   966 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   967 still lacks various theorems and concrete record syntax;
   968 
   969 
   970 *** HOLCF ***
   971 
   972 * removed "axioms" and "generated by" sections;
   973 
   974 * replaced "ops" section by extended "consts" section, which is capable of
   975   handling the continuous function space "->" directly;
   976 
   977 * domain package:
   978   . proves theorems immediately and stores them in the theory,
   979   . creates hierachical name space,
   980   . now uses normal mixfix annotations (instead of cinfix...),
   981   . minor changes to some names and values (for consistency),
   982   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   983   . separator between mutual domain defs: changed "," to "and",
   984   . improved handling of sort constraints;  now they have to
   985     appear on the left-hand side of the equations only;
   986 
   987 * fixed LAM <x,y,zs>.b syntax;
   988 
   989 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   990 adm (%x. P (t x)), where P is chainfinite and t continuous;
   991 
   992 
   993 *** FOL and ZF ***
   994 
   995 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
   996   with `addloop' of the simplifier to faciliate case splitting in premises.
   997 
   998 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   999 in HOL, they strip ALL and --> from proved theorems;
  1000 
  1001 
  1002 
  1003 New in Isabelle94-8 (May 1997)
  1004 ------------------------------
  1005 
  1006 *** General Changes ***
  1007 
  1008 * new utilities to build / run / maintain Isabelle etc. (in parts
  1009 still somewhat experimental); old Makefiles etc. still functional;
  1010 
  1011 * new 'Isabelle System Manual';
  1012 
  1013 * INSTALL text, together with ./configure and ./build scripts;
  1014 
  1015 * reimplemented type inference for greater efficiency, better error
  1016 messages and clean internal interface;
  1017 
  1018 * prlim command for dealing with lots of subgoals (an easier way of
  1019 setting goals_limit);
  1020 
  1021 
  1022 *** Syntax ***
  1023 
  1024 * supports alternative (named) syntax tables (parser and pretty
  1025 printer); internal interface is provided by add_modesyntax(_i);
  1026 
  1027 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1028 be used in conjunction with the Isabelle symbol font; uses the
  1029 "symbols" syntax table;
  1030 
  1031 * added token_translation interface (may translate name tokens in
  1032 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1033 the current print_mode); IMPORTANT: user print translation functions
  1034 are responsible for marking newly introduced bounds
  1035 (Syntax.mark_boundT);
  1036 
  1037 * token translations for modes "xterm" and "xterm_color" that display
  1038 names in bold, underline etc. or colors (which requires a color
  1039 version of xterm);
  1040 
  1041 * infixes may now be declared with names independent of their syntax;
  1042 
  1043 * added typed_print_translation (like print_translation, but may
  1044 access type of constant);
  1045 
  1046 
  1047 *** Classical Reasoner ***
  1048 
  1049 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1050 some limitations.  Blast_tac...
  1051   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1052   + ignores elimination rules that don't have the correct format
  1053         (the conclusion MUST be a formula variable)
  1054   + ignores types, which can make HOL proofs fail
  1055   + rules must not require higher-order unification, e.g. apply_type in ZF
  1056     [message "Function Var's argument not a bound variable" relates to this]
  1057   + its proof strategy is more general but can actually be slower
  1058 
  1059 * substitution with equality assumptions no longer permutes other
  1060 assumptions;
  1061 
  1062 * minor changes in semantics of addafter (now called addaltern); renamed
  1063 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1064 (and access functions for it);
  1065 
  1066 * improved combination of classical reasoner and simplifier:
  1067   + functions for handling clasimpsets
  1068   + improvement of addss: now the simplifier is called _after_ the
  1069     safe steps.
  1070   + safe variant of addss called addSss: uses safe simplifications
  1071     _during_ the safe steps. It is more complete as it allows multiple
  1072     instantiations of unknowns (e.g. with slow_tac).
  1073 
  1074 *** Simplifier ***
  1075 
  1076 * added interface for simplification procedures (functions that
  1077 produce *proven* rewrite rules on the fly, depending on current
  1078 redex);
  1079 
  1080 * ordering on terms as parameter (used for ordered rewriting);
  1081 
  1082 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1083 
  1084 * the solver is now split into a safe and an unsafe part.
  1085 This should be invisible for the normal user, except that the
  1086 functions setsolver and addsolver have been renamed to setSolver and
  1087 addSolver; added safe_asm_full_simp_tac;
  1088 
  1089 
  1090 *** HOL ***
  1091 
  1092 * a generic induction tactic `induct_tac' which works for all datatypes and
  1093 also for type `nat';
  1094 
  1095 * a generic case distinction tactic `exhaust_tac' which works for all
  1096 datatypes and also for type `nat';
  1097 
  1098 * each datatype comes with a function `size';
  1099 
  1100 * patterns in case expressions allow tuple patterns as arguments to
  1101 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1102 
  1103 * primrec now also works with type nat;
  1104 
  1105 * recdef: a new declaration form, allows general recursive functions to be
  1106 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1107 
  1108 * the constant for negation has been renamed from "not" to "Not" to
  1109 harmonize with FOL, ZF, LK, etc.;
  1110 
  1111 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1112 infinite lists;
  1113 
  1114 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1115 
  1116 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1117 problems in commutative rings, using axiomatic type classes for + and *;
  1118 
  1119 * more examples in HOL/MiniML and HOL/Auth;
  1120 
  1121 * more default rewrite rules for quantifiers, union/intersection;
  1122 
  1123 * a new constant `arbitrary == @x.False';
  1124 
  1125 * HOLCF/IOA replaces old HOL/IOA;
  1126 
  1127 * HOLCF changes: derived all rules and arities
  1128   + axiomatic type classes instead of classes
  1129   + typedef instead of faking type definitions
  1130   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1131   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1132   + eliminated the types void, one, tr
  1133   + use unit lift and bool lift (with translations) instead of one and tr
  1134   + eliminated blift from Lift3.thy (use Def instead of blift)
  1135   all eliminated rules are derived as theorems --> no visible changes ;
  1136 
  1137 
  1138 *** ZF ***
  1139 
  1140 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1141 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1142 as ZF_cs addSIs [equalityI];
  1143 
  1144 
  1145 
  1146 New in Isabelle94-7 (November 96)
  1147 ---------------------------------
  1148 
  1149 * allowing negative levels (as offsets) in prlev and choplev;
  1150 
  1151 * super-linear speedup for large simplifications;
  1152 
  1153 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1154 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1155 FAIL); can suppress it using the command Delsimps (ex_simps @
  1156 all_simps); De Morgan laws are also now included, by default;
  1157 
  1158 * improved printing of ==>  :  ~:
  1159 
  1160 * new object-logic "Sequents" adds linear logic, while replacing LK
  1161 and Modal (thanks to Sara Kalvala);
  1162 
  1163 * HOL/Auth: correctness proofs for authentication protocols;
  1164 
  1165 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1166 examples on HOL/Auth);
  1167 
  1168 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1169 the rewriter and classical reasoner simultaneously;
  1170 
  1171 * function uresult no longer returns theorems in "standard" format;
  1172 regain previous version by: val uresult = standard o uresult;
  1173 
  1174 
  1175 
  1176 New in Isabelle94-6
  1177 -------------------
  1178 
  1179 * oracles -- these establish an interface between Isabelle and trusted
  1180 external reasoners, which may deliver results as theorems;
  1181 
  1182 * proof objects (in particular record all uses of oracles);
  1183 
  1184 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1185 
  1186 * "constdefs" section in theory files;
  1187 
  1188 * "primrec" section (HOL) no longer requires names;
  1189 
  1190 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1191 
  1192 
  1193 
  1194 New in Isabelle94-5
  1195 -------------------
  1196 
  1197 * reduced space requirements;
  1198 
  1199 * automatic HTML generation from theories;
  1200 
  1201 * theory files no longer require "..." (quotes) around most types;
  1202 
  1203 * new examples, including two proofs of the Church-Rosser theorem;
  1204 
  1205 * non-curried (1994) version of HOL is no longer distributed;
  1206 
  1207 
  1208 
  1209 New in Isabelle94-4
  1210 -------------------
  1211 
  1212 * greatly reduced space requirements;
  1213 
  1214 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1215 
  1216 * searchable theorem database (see the section "Retrieving theorems" on
  1217 page 8 of the Reference Manual);
  1218 
  1219 * new examples, including Grabczewski's monumental case study of the
  1220 Axiom of Choice;
  1221 
  1222 * The previous version of HOL renamed to Old_HOL;
  1223 
  1224 * The new version of HOL (previously called CHOL) uses a curried syntax
  1225 for functions.  Application looks like f a b instead of f(a,b);
  1226 
  1227 * Mutually recursive inductive definitions finally work in HOL;
  1228 
  1229 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1230 translates to the operator "split";
  1231 
  1232 
  1233 
  1234 New in Isabelle94-3
  1235 -------------------
  1236 
  1237 * new infix operator, addss, allowing the classical reasoner to
  1238 perform simplification at each step of its search.  Example:
  1239         fast_tac (cs addss ss)
  1240 
  1241 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1242 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1243 look like (a,b) instead of <a,b>;
  1244 
  1245 * PLEASE NOTE: CHOL will eventually replace HOL!
  1246 
  1247 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1248 It translates to the operator "split".  A new theory of integers is available;
  1249 
  1250 * In ZF, integer numerals now denote two's-complement binary integers.
  1251 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1252 
  1253 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1254 of the Axiom of Choice;
  1255 
  1256 
  1257 
  1258 New in Isabelle94-2
  1259 -------------------
  1260 
  1261 * Significantly faster resolution;
  1262 
  1263 * the different sections in a .thy file can now be mixed and repeated
  1264 freely;
  1265 
  1266 * Database of theorems for FOL, HOL and ZF.  New
  1267 commands including qed, qed_goal and bind_thm store theorems in the database.
  1268 
  1269 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1270 a given theory (thms_of), or find out what theory a theorem was proved in
  1271 (theory_of_thm);
  1272 
  1273 * Bugs fixed in the inductive definition and datatype packages;
  1274 
  1275 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1276 and HOL_dup_cs obsolete;
  1277 
  1278 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1279 have been removed;
  1280 
  1281 * Simpler definition of function space in ZF;
  1282 
  1283 * new results about cardinal and ordinal arithmetic in ZF;
  1284 
  1285 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1286 types;
  1287 
  1288 
  1289 $Id$