NEWS
author wenzelm
Thu Mar 30 15:13:59 2000 +0200 (2000-03-30)
changeset 8621 8ba0f90f6f35
parent 8603 805910de7be0
child 8626 76e3913ff421
permissions -rw-r--r--
* Isar/Pure: local results and corresponding term bindings are now
subject to Hindley-Milner polymorphism (similar to ML); this
accommodates incremental type-inference nicely;
* Isar/Pure: new calculational elements 'moreover' and 'ultimately'
support plain accumulation of results, without applying any rules yet;
     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    12 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;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 * HOL: simplification no longer dives into case-expressions
    15 
    16 * ML: PureThy.add_thms/add_axioms/add_defs return theorems as well;
    17 
    18 
    19 *** Document preparation ***
    20 
    21 * isatool mkdir provides easy setup of Isabelle session directories,
    22 including proper document sources;
    23 
    24 * generated LaTeX sources are now deleted after successful run
    25 (isatool document -c); may retain a copy somewhere else via -D option
    26 of isatool usedir;
    27 
    28 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
    29 style files, achieving self-contained LaTeX sources;
    30 
    31 * old-style theories now produce (crude) LaTeX output as well;
    32 
    33 
    34 *** Isar ***
    35 
    36 * Pure: local results and corresponding term bindings are now subject
    37 to Hindley-Milner polymorphism (similar to ML); this accommodates
    38 incremental type-inference nicely;
    39 
    40 * Pure: new 'obtain' language element supports generalized existence
    41 reasoning;
    42 
    43 * Pure: new calculational elements 'moreover' and 'ultimately' support
    44 plain accumulation of results, without applying any rules yet;
    45 
    46 * Pure: scalable support for case-analysis type proofs: new 'case'
    47 language element refers to local contexts symbolically, as produced by
    48 certain proof methods; internally, case names are attached to theorems
    49 as "tags";
    50 
    51 * Pure now provides its own version of intro/elim/dest attributes;
    52 useful for building new logics, but beware of confusion with the
    53 Provers/classical ones;
    54 
    55 * Provers: splitter support (via 'split' attribute and 'simp' method
    56 modifier); 'simp' method: 'only:' modifier removes loopers as well
    57 (including splits);
    58 
    59 * HOL: new proof method 'cases' and improved version of 'induct' now
    60 support named cases; major packages (inductive, datatype, primrec,
    61 recdef) support case names and properly name parameters;
    62 
    63 * HOL: removed 'case_split' thm binding, should use 'cases' proof
    64 method anyway;
    65 
    66 * names of theorems etc. may be natural numbers as well;
    67 
    68 * Provers: intro/elim/dest attributes: changed ! / !! flags to ? / ??;
    69 
    70 * 'pr' command: optional goals_limit argument;
    71 
    72 * diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
    73 additional print modes to be specified; e.g. "pr(latex)" will print
    74 proof state according to the Isabelle LaTeX style;
    75 
    76 * improved support for emulating tactic scripts, including proof
    77 methods 'tactic', 'res_inst_tac' etc., 'subgoal_tac', and 'case_tac' /
    78 'induct_tac' (for HOL datatypes);
    79 
    80 
    81 
    82 *** HOL ***
    83 
    84 * HOL/Algebra: new theory of rings and univariate polynomials, by
    85 Clemens Ballarin;
    86 
    87 * HOL/record: fixed select-update simplification procedure to handle
    88 extended records as well; admit "r" as field name;
    89 
    90 * HOL/ex: new theory Factorization proving the Fundamental Theorem of
    91 Arithmetic, by Thomas M Rasmussen;
    92 
    93 * HOL/ex/Multiquote: multiple nested quotations and anti-quotations --
    94 basically a generalized version of de-Bruijn representation; very
    95 useful in avoiding lifting all operations;
    96 
    97 * new version of "case_tac" subsumes both boolean case split and
    98 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
    99 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   100 
   101 * HOL: simplification no longer dives into case-expressions: only the
   102 selector expression is simplified, but not the remaining arms. To enable full
   103 simplification of case-expressions for datatype t, you need to remove
   104 t.weak_case_cong from the simpset, either permanently
   105 (Delcongs[thm"t.weak_case_cong"];) or locally (delcongs [...]).
   106 
   107 
   108 *** General ***
   109 
   110 * compression of ML heaps images may now be controlled via -c option
   111 of isabelle and isatool usedir (currently only observed by Poly/ML);
   112 
   113 * ML: new combinators |>> and |>>> for incremental transformations
   114 with secondary results (e.g. certain theory extensions):
   115 
   116 
   117 
   118 New in Isabelle99 (October 1999)
   119 --------------------------------
   120 
   121 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   122 
   123 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   124 are no longer simplified.  (This allows the simplifier to unfold recursive
   125 functional programs.)  To restore the old behaviour, declare
   126 
   127     Delcongs [if_weak_cong];
   128 
   129 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   130 complement;
   131 
   132 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   133 
   134 * HOL/datatype: mutual_induct_tac no longer exists --
   135   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   136 
   137 * HOL/typedef: fixed type inference for representing set; type
   138 arguments now have to occur explicitly on the rhs as type constraints;
   139 
   140 * ZF: The con_defs part of an inductive definition may no longer refer
   141 to constants declared in the same theory;
   142 
   143 * HOL, ZF: the function mk_cases, generated by the inductive
   144 definition package, has lost an argument.  To simplify its result, it
   145 uses the default simpset instead of a supplied list of theorems.
   146 
   147 * HOL/List: the constructors of type list are now Nil and Cons;
   148 
   149 * Simplifier: the type of the infix ML functions
   150 	setSSolver addSSolver setSolver addSolver
   151 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   152 for packaging solvers. A solver is created via
   153 	mk_solver: string -> (thm list -> int -> tactic) -> solver
   154 where the string argument is only a comment.
   155 
   156 
   157 *** Proof tools ***
   158 
   159 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   160 decision procedure for linear arithmetic. Currently it is used for
   161 types `nat', `int', and `real' in HOL (see below); it can, should and
   162 will be instantiated for other types and logics as well.
   163 
   164 * The simplifier now accepts rewrite rules with flexible heads, eg
   165      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   166   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   167   matching.
   168 
   169 
   170 *** General ***
   171 
   172 * New Isabelle/Isar subsystem provides an alternative to traditional
   173 tactical theorem proving; together with the ProofGeneral/isar user
   174 interface it offers an interactive environment for developing human
   175 readable proof documents (Isar == Intelligible semi-automated
   176 reasoning); for further information see isatool doc isar-ref,
   177 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   178 
   179 * improved presentation of theories: better HTML markup (including
   180 colors), graph views in several sizes; isatool usedir now provides a
   181 proper interface for user theories (via -P option); actual document
   182 preparation based on (PDF)LaTeX is available as well (for new-style
   183 theories only); see isatool doc system for more information;
   184 
   185 * native support for Proof General, both for classic Isabelle and
   186 Isabelle/Isar;
   187 
   188 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   189 using the graph browser tool;
   190 
   191 * Isabelle manuals now also available as PDF;
   192 
   193 * theory loader rewritten from scratch (may not be fully
   194 bug-compatible); old loadpath variable has been replaced by show_path,
   195 add_path, del_path, reset_path functions; new operations such as
   196 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   197 isatool doc ref);
   198 
   199 * improved isatool install: option -k creates KDE application icon,
   200 option -p DIR installs standalone binaries;
   201 
   202 * added ML_PLATFORM setting (useful for cross-platform installations);
   203 more robust handling of platform specific ML images for SML/NJ;
   204 
   205 * the settings environment is now statically scoped, i.e. it is never
   206 created again in sub-processes invoked from isabelle, isatool, or
   207 Isabelle;
   208 
   209 * path element specification '~~' refers to '$ISABELLE_HOME';
   210 
   211 * in locales, the "assumes" and "defines" parts may be omitted if
   212 empty;
   213 
   214 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   215 long arrows);
   216 
   217 * new print_mode "HTML";
   218 
   219 * new flag show_tags controls display of tags of theorems (which are
   220 basically just comments that may be attached by some tools);
   221 
   222 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   223 mode and goal output format:
   224 
   225 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   226 244c244
   227 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   228 ---
   229 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   230 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   231 181c181
   232 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   233 ---
   234 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   235 
   236 * function bind_thms stores lists of theorems (cf. bind_thm);
   237 
   238 * new shorthand tactics ftac, eatac, datac, fatac;
   239 
   240 * qed (and friends) now accept "" as result name; in that case the
   241 theorem is not stored, but proper checks and presentation of the
   242 result still apply;
   243 
   244 * theorem database now also indexes constants "Trueprop", "all",
   245 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   246 
   247 
   248 *** HOL ***
   249 
   250 ** HOL arithmetic **
   251 
   252 * There are now decision procedures for linear arithmetic over nat and
   253 int:
   254 
   255 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   256 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   257 are treated as atomic; subformulae not involving type `nat' or `int'
   258 are ignored; quantified subformulae are ignored unless they are
   259 positive universal or negative existential. The tactic has to be
   260 invoked by hand and can be a little bit slow. In particular, the
   261 running time is exponential in the number of occurrences of `min' and
   262 `max', and `-' on `nat'.
   263 
   264 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   265 (negated) (in)equalities among the premises and the conclusion into
   266 account (i.e. no compound formulae) and does not know about `min' and
   267 `max', and `-' on `nat'. It is fast and is used automatically by the
   268 simplifier.
   269 
   270 NB: At the moment, these decision procedures do not cope with mixed
   271 nat/int formulae where the two parts interact, such as `m < n ==>
   272 int(m) < int(n)'.
   273 
   274 * HOL/Numeral provides a generic theory of numerals (encoded
   275 efficiently as bit strings); setup for types nat/int/real is in place;
   276 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   277 int, existing theories and proof scripts may require a few additional
   278 type constraints;
   279 
   280 * integer division and remainder can now be performed on constant
   281 arguments;
   282 
   283 * many properties of integer multiplication, division and remainder
   284 are now available;
   285 
   286 * An interface to the Stanford Validity Checker (SVC) is available through the
   287 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   288 are proved automatically.  SVC must be installed separately, and its results
   289 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   290 invocation of the underlying oracle).  For SVC see
   291   http://verify.stanford.edu/SVC
   292 
   293 * IsaMakefile: the HOL-Real target now builds an actual image;
   294 
   295 
   296 ** HOL misc **
   297 
   298 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   299 (in Isabelle/Isar) -- by Gertrud Bauer;
   300 
   301 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   302 analysis for assembly languages with subtypes;
   303 
   304 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   305 -- avoids syntactic ambiguities and treats state, transition, and
   306 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   307 changed syntax and (many) tactics;
   308 
   309 * HOL/inductive: Now also handles more general introduction rules such
   310   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   311   theorems are now maintained within the theory (maintained via the
   312   "mono" attribute);
   313 
   314 * HOL/datatype: Now also handles arbitrarily branching datatypes
   315   (using function types) such as
   316 
   317   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   318 
   319 * HOL/record: record_simproc (part of the default simpset) takes care
   320 of selectors applied to updated records; record_split_tac is no longer
   321 part of the default claset; update_defs may now be removed from the
   322 simpset in many cases; COMPATIBILITY: old behavior achieved by
   323 
   324   claset_ref () := claset() addSWrapper record_split_wrapper;
   325   Delsimprocs [record_simproc]
   326 
   327 * HOL/typedef: fixed type inference for representing set; type
   328 arguments now have to occur explicitly on the rhs as type constraints;
   329 
   330 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   331 names rather than an ML expression;
   332 
   333 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   334 supplied later.  Program schemes can be defined, such as
   335     "While B C s = (if B s then While B C (C s) else s)"
   336 where the well-founded relation can be chosen after B and C have been given.
   337 
   338 * HOL/List: the constructors of type list are now Nil and Cons;
   339 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   340 course, ML tools referring to List.list.op # etc. have to be adapted;
   341 
   342 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   343 disabled by default; run isabelle with option -m HOL to get back to
   344 the original Gordon/HOL-style output;
   345 
   346 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   347 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   348 
   349 * HOL basic syntax simplified (more orthogonal): all variants of
   350 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   351 Eps operator is provided as well: "SOME x. P[x]";
   352 
   353 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   354 
   355 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   356 thus available for user theories;
   357 
   358 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   359 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   360 time;
   361 
   362 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   363 several times and then mp;
   364 
   365 
   366 *** LK ***
   367 
   368 * the notation <<...>> is now available as a notation for sequences of
   369 formulas;
   370 
   371 * the simplifier is now installed
   372 
   373 * the axiom system has been generalized (thanks to Soren Heilmann) 
   374 
   375 * the classical reasoner now has a default rule database
   376 
   377 
   378 *** ZF ***
   379 
   380 * new primrec section allows primitive recursive functions to be given
   381 directly (as in HOL) over datatypes and the natural numbers;
   382 
   383 * new tactics induct_tac and exhaust_tac for induction (or case
   384 analysis) over datatypes and the natural numbers;
   385 
   386 * the datatype declaration of type T now defines the recursor T_rec;
   387 
   388 * simplification automatically does freeness reasoning for datatype
   389 constructors;
   390 
   391 * automatic type-inference, with AddTCs command to insert new
   392 type-checking rules;
   393 
   394 * datatype introduction rules are now added as Safe Introduction rules
   395 to the claset;
   396 
   397 * the syntax "if P then x else y" is now available in addition to
   398 if(P,x,y);
   399 
   400 
   401 *** Internal programming interfaces ***
   402 
   403 * tuned simplifier trace output; new flag debug_simp;
   404 
   405 * structures Vartab / Termtab (instances of TableFun) offer efficient
   406 tables indexed by indexname_ord / term_ord (compatible with aconv);
   407 
   408 * AxClass.axclass_tac lost the theory argument;
   409 
   410 * tuned current_goals_markers semantics: begin / end goal avoids
   411 printing empty lines;
   412 
   413 * removed prs and prs_fn hook, which was broken because it did not
   414 include \n in its semantics, forcing writeln to add one
   415 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   416 string -> unit if you really want to output text without newline;
   417 
   418 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   419 plain output, interface builders may have to enable 'isabelle_font'
   420 mode to get Isabelle font glyphs as before;
   421 
   422 * refined token_translation interface; INCOMPATIBILITY: output length
   423 now of type real instead of int;
   424 
   425 * theory loader actions may be traced via new ThyInfo.add_hook
   426 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   427 your own database of information attached to *whole* theories -- as
   428 opposed to intra-theory data slots offered via TheoryDataFun;
   429 
   430 * proper handling of dangling sort hypotheses (at last!);
   431 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   432 extra sort hypotheses that can be witnessed from the type signature;
   433 the force_strip_shyps flag is gone, any remaining shyps are simply
   434 left in the theorem (with a warning issued by strip_shyps_warning);
   435 
   436 
   437 
   438 New in Isabelle98-1 (October 1998)
   439 ----------------------------------
   440 
   441 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   442 
   443 * several changes of automated proof tools;
   444 
   445 * HOL: major changes to the inductive and datatype packages, including
   446 some minor incompatibilities of theory syntax;
   447 
   448 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   449 called `inj_on';
   450 
   451 * HOL: removed duplicate thms in Arith:
   452   less_imp_add_less  should be replaced by  trans_less_add1
   453   le_imp_add_le      should be replaced by  trans_le_add1
   454 
   455 * HOL: unary minus is now overloaded (new type constraints may be
   456 required);
   457 
   458 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   459 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   460 now taken as an integer constant.
   461 
   462 * Pure: ML function 'theory_of' renamed to 'theory';
   463 
   464 
   465 *** Proof tools ***
   466 
   467 * Simplifier:
   468   1. Asm_full_simp_tac is now more aggressive.
   469      1. It will sometimes reorient premises if that increases their power to
   470         simplify.
   471      2. It does no longer proceed strictly from left to right but may also
   472         rotate premises to achieve further simplification.
   473      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   474      old Asm_full_simp_tac in that it does not rotate premises.
   475   2. The simplifier now knows a little bit about nat-arithmetic.
   476 
   477 * Classical reasoner: wrapper mechanism for the classical reasoner now
   478 allows for selected deletion of wrappers, by introduction of names for
   479 wrapper functionals.  This implies that addbefore, addSbefore,
   480 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   481 and that adding two tactics with the same name overwrites the first
   482 one (emitting a warning).
   483   type wrapper = (int -> tactic) -> (int -> tactic)
   484   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   485   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   486   delWrapper, delSWrapper: claset *  string            -> claset
   487   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   488 
   489 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   490 semantics; addbefore now affects only the unsafe part of step_tac
   491 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   492 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   493 by Force_tac;
   494 
   495 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   496 compWrapper; added safe wrapper (and access functions for it);
   497 
   498 * HOL/split_all_tac is now much faster and fails if there is nothing
   499 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   500 and the names of the automatically generated variables have changed.
   501 split_all_tac has moved within claset() from unsafe wrappers to safe
   502 wrappers, which means that !!-bound variables are split much more
   503 aggressively, and safe_tac and clarify_tac now split such variables.
   504 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   505 Note: the same holds for record_split_tac, which does the job of
   506 split_all_tac for record fields.
   507 
   508 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   509 permanently to the default simpset using Addsplits just like
   510 Addsimps. They can be removed via Delsplits just like
   511 Delsimps. Lower-case versions are also available.
   512 
   513 * HOL/Simplifier: The rule split_if is now part of the default
   514 simpset. This means that the simplifier will eliminate all occurrences
   515 of if-then-else in the conclusion of a goal. To prevent this, you can
   516 either remove split_if completely from the default simpset by
   517 `Delsplits [split_if]' or remove it in a specific call of the
   518 simplifier using `... delsplits [split_if]'.  You can also add/delete
   519 other case splitting rules to/from the default simpset: every datatype
   520 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   521 t is the name of the datatype).
   522 
   523 * Classical reasoner / Simplifier combination: new force_tac (and
   524 derivatives Force_tac, force) combines rewriting and classical
   525 reasoning (and whatever other tools) similarly to auto_tac, but is
   526 aimed to solve the given subgoal completely.
   527 
   528 
   529 *** General ***
   530 
   531 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   532 and `goalw': the theory is no longer needed as an explicit argument -
   533 the current theory context is used; assumptions are no longer returned
   534 at the ML-level unless one of them starts with ==> or !!; it is
   535 recommended to convert to these new commands using isatool fixgoal
   536 (backup your sources first!);
   537 
   538 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   539 the current theory context, and 'theory' to lookup stored theories;
   540 
   541 * new theory section 'locale' for declaring constants, assumptions and
   542 definitions that have local scope;
   543 
   544 * new theory section 'nonterminals' for purely syntactic types;
   545 
   546 * new theory section 'setup' for generic ML setup functions
   547 (e.g. package initialization);
   548 
   549 * the distribution now includes Isabelle icons: see
   550 lib/logo/isabelle-{small,tiny}.xpm;
   551 
   552 * isatool install - install binaries with absolute references to
   553 ISABELLE_HOME/bin;
   554 
   555 * isatool logo -- create instances of the Isabelle logo (as EPS);
   556 
   557 * print mode 'emacs' reserved for Isamode;
   558 
   559 * support multiple print (ast) translations per constant name;
   560 
   561 * theorems involving oracles are now printed with a suffixed [!];
   562 
   563 
   564 *** HOL ***
   565 
   566 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   567 
   568 * HOL/inductive package reorganized and improved: now supports mutual
   569 definitions such as
   570 
   571   inductive EVEN ODD
   572     intrs
   573       null "0 : EVEN"
   574       oddI "n : EVEN ==> Suc n : ODD"
   575       evenI "n : ODD ==> Suc n : EVEN"
   576 
   577 new theorem list "elims" contains an elimination rule for each of the
   578 recursive sets; inductive definitions now handle disjunctive premises
   579 correctly (also ZF);
   580 
   581 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   582 "mutual_induct" no longer exists - the induction rule is always
   583 contained in "induct";
   584 
   585 
   586 * HOL/datatype package re-implemented and greatly improved: now
   587 supports mutually recursive datatypes such as
   588 
   589   datatype
   590     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   591             | SUM ('a aexp) ('a aexp)
   592             | DIFF ('a aexp) ('a aexp)
   593             | NUM 'a
   594   and
   595     'a bexp = LESS ('a aexp) ('a aexp)
   596             | AND ('a bexp) ('a bexp)
   597             | OR ('a bexp) ('a bexp)
   598 
   599 as well as indirectly recursive datatypes such as
   600 
   601   datatype
   602     ('a, 'b) term = Var 'a
   603                   | App 'b ((('a, 'b) term) list)
   604 
   605 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   606 induction on mutually / indirectly recursive datatypes.
   607 
   608 Primrec equations are now stored in theory and can be accessed via
   609 <function_name>.simps.
   610 
   611 INCOMPATIBILITIES:
   612 
   613   - Theories using datatypes must now have theory Datatype as an
   614     ancestor.
   615   - The specific <typename>.induct_tac no longer exists - use the
   616     generic induct_tac instead.
   617   - natE has been renamed to nat.exhaust - use exhaust_tac
   618     instead of res_inst_tac ... natE. Note that the variable
   619     names in nat.exhaust differ from the names in natE, this
   620     may cause some "fragile" proofs to fail.
   621   - The theorems split_<typename>_case and split_<typename>_case_asm
   622     have been renamed to <typename>.split and <typename>.split_asm.
   623   - Since default sorts of type variables are now handled correctly,
   624     some datatype definitions may have to be annotated with explicit
   625     sort constraints.
   626   - Primrec definitions no longer require function name and type
   627     of recursive argument.
   628 
   629 Consider using isatool fixdatatype to adapt your theories and proof
   630 scripts to the new package (backup your sources first!).
   631 
   632 
   633 * HOL/record package: considerably improved implementation; now
   634 includes concrete syntax for record types, terms, updates; theorems
   635 for surjective pairing and splitting !!-bound record variables; proof
   636 support is as follows:
   637 
   638   1) standard conversions (selectors or updates applied to record
   639 constructor terms) are part of the standard simpset;
   640 
   641   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   642 made part of standard simpset and claset via addIffs;
   643 
   644   3) a tactic for record field splitting (record_split_tac) is part of
   645 the standard claset (addSWrapper);
   646 
   647 To get a better idea about these rules you may retrieve them via
   648 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   649 the name of your record type.
   650 
   651 The split tactic 3) conceptually simplifies by the following rule:
   652 
   653   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   654 
   655 Thus any record variable that is bound by meta-all will automatically
   656 blow up into some record constructor term, consequently the
   657 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   658 solve record problems automatically.
   659 
   660 
   661 * reorganized the main HOL image: HOL/Integ and String loaded by
   662 default; theory Main includes everything;
   663 
   664 * automatic simplification of integer sums and comparisons, using cancellation;
   665 
   666 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   667 
   668 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   669 
   670 * many new identities for unions, intersections, set difference, etc.;
   671 
   672 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   673 called split_if, split_split, split_sum_case and split_nat_case (to go
   674 with add/delsplits);
   675 
   676 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   677 (?x::unit) = (); this is made part of the default simpset, which COULD
   678 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   679 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   680 unit_abs_eta_conv is added in order to counter the effect of
   681 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   682 %u.f();
   683 
   684 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   685 makes more sense);
   686 
   687 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   688   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   689   disjointness reasoning but breaking a few old proofs.
   690 
   691 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   692 to 'converse' from 'inverse' (for compatibility with ZF and some
   693 literature);
   694 
   695 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   696 the well-founded relation;
   697 
   698 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   699     Compl A.  The "Compl" syntax remains available as input syntax for this
   700     release ONLY.
   701 
   702 * HOL/Update: new theory of function updates:
   703     f(a:=b) == %x. if x=a then b else f x
   704 may also be iterated as in f(a:=b,c:=d,...);
   705 
   706 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   707 
   708 * HOL/List:
   709   - new function list_update written xs[i:=v] that updates the i-th
   710     list position. May also be iterated as in xs[i:=a,j:=b,...].
   711   - new function `upt' written [i..j(] which generates the list
   712     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   713     bound write [i..j], which is a shorthand for [i..j+1(].
   714   - new lexicographic orderings and corresponding wellfoundedness theorems.
   715 
   716 * HOL/Arith:
   717   - removed 'pred' (predecessor) function;
   718   - generalized some theorems about n-1;
   719   - many new laws about "div" and "mod";
   720   - new laws about greatest common divisors (see theory ex/Primes);
   721 
   722 * HOL/Relation: renamed the relational operator r^-1 "converse"
   723 instead of "inverse";
   724 
   725 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   726   of the multiset ordering;
   727 
   728 * directory HOL/Real: a construction of the reals using Dedekind cuts
   729   (not included by default);
   730 
   731 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   732 
   733 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   734   programs, i.e. different program variables may have different types.
   735 
   736 * calling (stac rew i) now fails if "rew" has no effect on the goal
   737   [previously, this check worked only if the rewrite rule was unconditional]
   738   Now rew can involve either definitions or equalities (either == or =).
   739 
   740 
   741 *** ZF ***
   742 
   743 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   744   only the theorems proved on ZF.ML;
   745 
   746 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   747   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   748   disjointness reasoning but breaking a few old proofs.
   749 
   750 * ZF/Update: new theory of function updates
   751     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   752   may also be iterated as in f(a:=b,c:=d,...);
   753 
   754 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   755 
   756 * calling (stac rew i) now fails if "rew" has no effect on the goal
   757   [previously, this check worked only if the rewrite rule was unconditional]
   758   Now rew can involve either definitions or equalities (either == or =).
   759 
   760 * case_tac provided for compatibility with HOL
   761     (like the old excluded_middle_tac, but with subgoals swapped)
   762 
   763 
   764 *** Internal programming interfaces ***
   765 
   766 * Pure: several new basic modules made available for general use, see
   767 also src/Pure/README;
   768 
   769 * improved the theory data mechanism to support encapsulation (data
   770 kind name replaced by private Object.kind, acting as authorization
   771 key); new type-safe user interface via functor TheoryDataFun; generic
   772 print_data function becomes basically useless;
   773 
   774 * removed global_names compatibility flag -- all theory declarations
   775 are qualified by default;
   776 
   777 * module Pure/Syntax now offers quote / antiquote translation
   778 functions (useful for Hoare logic etc. with implicit dependencies);
   779 see HOL/ex/Antiquote for an example use;
   780 
   781 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   782 cterm -> thm;
   783 
   784 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   785 subgoal;
   786 
   787 * Display.print_goals function moved to Locale.print_goals;
   788 
   789 * standard print function for goals supports current_goals_markers
   790 variable for marking begin of proof, end of proof, start of goal; the
   791 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   792 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   793 for example;
   794 
   795 
   796 
   797 New in Isabelle98 (January 1998)
   798 --------------------------------
   799 
   800 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   801 
   802 * changed lexical syntax of terms / types: dots made part of long
   803 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   804 
   805 * simpset (and claset) reference variable replaced by functions
   806 simpset / simpset_ref;
   807 
   808 * no longer supports theory aliases (via merge) and non-trivial
   809 implicit merge of thms' signatures;
   810 
   811 * most internal names of constants changed due to qualified names;
   812 
   813 * changed Pure/Sequence interface (see Pure/seq.ML);
   814 
   815 
   816 *** General Changes ***
   817 
   818 * hierachically structured name spaces (for consts, types, axms, thms
   819 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   820 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   821 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   822 long_names for fully qualified output names; NOTE: ML programs
   823 (special tactics, packages etc.) referring to internal names may have
   824 to be adapted to cope with fully qualified names; in case of severe
   825 backward campatibility problems try setting 'global_names' at compile
   826 time to have enrything declared within a flat name space; one may also
   827 fine tune name declarations in theories via the 'global' and 'local'
   828 section;
   829 
   830 * reimplemented the implicit simpset and claset using the new anytype
   831 data filed in signatures; references simpset:simpset ref etc. are
   832 replaced by functions simpset:unit->simpset and
   833 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   834 to patch your ML files accordingly;
   835 
   836 * HTML output now includes theory graph data for display with Java
   837 applet or isatool browser; data generated automatically via isatool
   838 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   839 
   840 * defs may now be conditional; improved rewrite_goals_tac to handle
   841 conditional equations;
   842 
   843 * defs now admits additional type arguments, using TYPE('a) syntax;
   844 
   845 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   846 creates a new theory node; implicit merge of thms' signatures is
   847 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   848 transfer:theory->thm->thm in (rare) cases;
   849 
   850 * improved handling of draft signatures / theories; draft thms (and
   851 ctyps, cterms) are automatically promoted to real ones;
   852 
   853 * slightly changed interfaces for oracles: admit many per theory, named
   854 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   855 
   856 * print_goals: optional output of const types (set show_consts and
   857 show_types);
   858 
   859 * improved output of warnings (###) and errors (***);
   860 
   861 * subgoal_tac displays a warning if the new subgoal has type variables;
   862 
   863 * removed old README and Makefiles;
   864 
   865 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   866 
   867 * removed obsolete init_pps and init_database;
   868 
   869 * deleted the obsolete tactical STATE, which was declared by
   870     fun STATE tacfun st = tacfun st st;
   871 
   872 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   873 (which abbreviates $HOME);
   874 
   875 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   876 use isatool fixseq to adapt your ML programs (this works for fully
   877 qualified references to the Sequence structure only!);
   878 
   879 * use_thy no longer requires writable current directory; it always
   880 reloads .ML *and* .thy file, if either one is out of date;
   881 
   882 
   883 *** Classical Reasoner ***
   884 
   885 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   886 tactics that use classical reasoning to simplify a subgoal without
   887 splitting it into several subgoals;
   888 
   889 * Safe_tac: like safe_tac but uses the default claset;
   890 
   891 
   892 *** Simplifier ***
   893 
   894 * added simplification meta rules:
   895     (asm_)(full_)simplify: simpset -> thm -> thm;
   896 
   897 * simplifier.ML no longer part of Pure -- has to be loaded by object
   898 logics (again);
   899 
   900 * added prems argument to simplification procedures;
   901 
   902 * HOL, FOL, ZF: added infix function `addsplits':
   903   instead of `<simpset> setloop (split_tac <thms>)'
   904   you can simply write `<simpset> addsplits <thms>'
   905 
   906 
   907 *** Syntax ***
   908 
   909 * TYPE('a) syntax for type reflection terms;
   910 
   911 * no longer handles consts with name "" -- declare as 'syntax' instead;
   912 
   913 * pretty printer: changed order of mixfix annotation preference (again!);
   914 
   915 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   916 
   917 
   918 *** HOL ***
   919 
   920 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   921   with `addloop' of the simplifier to faciliate case splitting in premises.
   922 
   923 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   924 
   925 * HOL/Auth: new protocol proofs including some for the Internet
   926   protocol TLS;
   927 
   928 * HOL/Map: new theory of `maps' a la VDM;
   929 
   930 * HOL/simplifier: simplification procedures nat_cancel_sums for
   931 cancelling out common nat summands from =, <, <= (in)equalities, or
   932 differences; simplification procedures nat_cancel_factor for
   933 cancelling common factor from =, <, <= (in)equalities over natural
   934 sums; nat_cancel contains both kinds of procedures, it is installed by
   935 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   936 
   937 * HOL/simplifier: terms of the form
   938   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   939   are rewritten to
   940   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   941   and those of the form
   942   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   943   are rewritten to
   944   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   945 
   946 * HOL/datatype
   947   Each datatype `t' now comes with a theorem `split_t_case' of the form
   948 
   949   P(t_case f1 ... fn x) =
   950      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   951         ...
   952        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   953      )
   954 
   955   and a theorem `split_t_case_asm' of the form
   956 
   957   P(t_case f1 ... fn x) =
   958     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   959         ...
   960        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   961      )
   962   which can be added to a simpset via `addsplits'. The existing theorems
   963   expand_list_case and expand_option_case have been renamed to
   964   split_list_case and split_option_case.
   965 
   966 * HOL/Arithmetic:
   967   - `pred n' is automatically converted to `n-1'.
   968     Users are strongly encouraged not to use `pred' any longer,
   969     because it will disappear altogether at some point.
   970   - Users are strongly encouraged to write "0 < n" rather than
   971     "n ~= 0". Theorems and proof tools have been modified towards this
   972     `standard'.
   973 
   974 * HOL/Lists:
   975   the function "set_of_list" has been renamed "set" (and its theorems too);
   976   the function "nth" now takes its arguments in the reverse order and
   977   has acquired the infix notation "!" as in "xs!n".
   978 
   979 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   980 
   981 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   982   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   983 
   984 * HOL/record: extensible records with schematic structural subtyping
   985 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   986 still lacks various theorems and concrete record syntax;
   987 
   988 
   989 *** HOLCF ***
   990 
   991 * removed "axioms" and "generated by" sections;
   992 
   993 * replaced "ops" section by extended "consts" section, which is capable of
   994   handling the continuous function space "->" directly;
   995 
   996 * domain package:
   997   . proves theorems immediately and stores them in the theory,
   998   . creates hierachical name space,
   999   . now uses normal mixfix annotations (instead of cinfix...),
  1000   . minor changes to some names and values (for consistency),
  1001   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1002   . separator between mutual domain defs: changed "," to "and",
  1003   . improved handling of sort constraints;  now they have to
  1004     appear on the left-hand side of the equations only;
  1005 
  1006 * fixed LAM <x,y,zs>.b syntax;
  1007 
  1008 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1009 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1010 
  1011 
  1012 *** FOL and ZF ***
  1013 
  1014 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1015   with `addloop' of the simplifier to faciliate case splitting in premises.
  1016 
  1017 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1018 in HOL, they strip ALL and --> from proved theorems;
  1019 
  1020 
  1021 
  1022 New in Isabelle94-8 (May 1997)
  1023 ------------------------------
  1024 
  1025 *** General Changes ***
  1026 
  1027 * new utilities to build / run / maintain Isabelle etc. (in parts
  1028 still somewhat experimental); old Makefiles etc. still functional;
  1029 
  1030 * new 'Isabelle System Manual';
  1031 
  1032 * INSTALL text, together with ./configure and ./build scripts;
  1033 
  1034 * reimplemented type inference for greater efficiency, better error
  1035 messages and clean internal interface;
  1036 
  1037 * prlim command for dealing with lots of subgoals (an easier way of
  1038 setting goals_limit);
  1039 
  1040 
  1041 *** Syntax ***
  1042 
  1043 * supports alternative (named) syntax tables (parser and pretty
  1044 printer); internal interface is provided by add_modesyntax(_i);
  1045 
  1046 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1047 be used in conjunction with the Isabelle symbol font; uses the
  1048 "symbols" syntax table;
  1049 
  1050 * added token_translation interface (may translate name tokens in
  1051 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1052 the current print_mode); IMPORTANT: user print translation functions
  1053 are responsible for marking newly introduced bounds
  1054 (Syntax.mark_boundT);
  1055 
  1056 * token translations for modes "xterm" and "xterm_color" that display
  1057 names in bold, underline etc. or colors (which requires a color
  1058 version of xterm);
  1059 
  1060 * infixes may now be declared with names independent of their syntax;
  1061 
  1062 * added typed_print_translation (like print_translation, but may
  1063 access type of constant);
  1064 
  1065 
  1066 *** Classical Reasoner ***
  1067 
  1068 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1069 some limitations.  Blast_tac...
  1070   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1071   + ignores elimination rules that don't have the correct format
  1072         (the conclusion MUST be a formula variable)
  1073   + ignores types, which can make HOL proofs fail
  1074   + rules must not require higher-order unification, e.g. apply_type in ZF
  1075     [message "Function Var's argument not a bound variable" relates to this]
  1076   + its proof strategy is more general but can actually be slower
  1077 
  1078 * substitution with equality assumptions no longer permutes other
  1079 assumptions;
  1080 
  1081 * minor changes in semantics of addafter (now called addaltern); renamed
  1082 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1083 (and access functions for it);
  1084 
  1085 * improved combination of classical reasoner and simplifier:
  1086   + functions for handling clasimpsets
  1087   + improvement of addss: now the simplifier is called _after_ the
  1088     safe steps.
  1089   + safe variant of addss called addSss: uses safe simplifications
  1090     _during_ the safe steps. It is more complete as it allows multiple
  1091     instantiations of unknowns (e.g. with slow_tac).
  1092 
  1093 *** Simplifier ***
  1094 
  1095 * added interface for simplification procedures (functions that
  1096 produce *proven* rewrite rules on the fly, depending on current
  1097 redex);
  1098 
  1099 * ordering on terms as parameter (used for ordered rewriting);
  1100 
  1101 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1102 
  1103 * the solver is now split into a safe and an unsafe part.
  1104 This should be invisible for the normal user, except that the
  1105 functions setsolver and addsolver have been renamed to setSolver and
  1106 addSolver; added safe_asm_full_simp_tac;
  1107 
  1108 
  1109 *** HOL ***
  1110 
  1111 * a generic induction tactic `induct_tac' which works for all datatypes and
  1112 also for type `nat';
  1113 
  1114 * a generic case distinction tactic `exhaust_tac' which works for all
  1115 datatypes and also for type `nat';
  1116 
  1117 * each datatype comes with a function `size';
  1118 
  1119 * patterns in case expressions allow tuple patterns as arguments to
  1120 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1121 
  1122 * primrec now also works with type nat;
  1123 
  1124 * recdef: a new declaration form, allows general recursive functions to be
  1125 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1126 
  1127 * the constant for negation has been renamed from "not" to "Not" to
  1128 harmonize with FOL, ZF, LK, etc.;
  1129 
  1130 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1131 infinite lists;
  1132 
  1133 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1134 
  1135 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1136 problems in commutative rings, using axiomatic type classes for + and *;
  1137 
  1138 * more examples in HOL/MiniML and HOL/Auth;
  1139 
  1140 * more default rewrite rules for quantifiers, union/intersection;
  1141 
  1142 * a new constant `arbitrary == @x.False';
  1143 
  1144 * HOLCF/IOA replaces old HOL/IOA;
  1145 
  1146 * HOLCF changes: derived all rules and arities
  1147   + axiomatic type classes instead of classes
  1148   + typedef instead of faking type definitions
  1149   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1150   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1151   + eliminated the types void, one, tr
  1152   + use unit lift and bool lift (with translations) instead of one and tr
  1153   + eliminated blift from Lift3.thy (use Def instead of blift)
  1154   all eliminated rules are derived as theorems --> no visible changes ;
  1155 
  1156 
  1157 *** ZF ***
  1158 
  1159 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1160 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1161 as ZF_cs addSIs [equalityI];
  1162 
  1163 
  1164 
  1165 New in Isabelle94-7 (November 96)
  1166 ---------------------------------
  1167 
  1168 * allowing negative levels (as offsets) in prlev and choplev;
  1169 
  1170 * super-linear speedup for large simplifications;
  1171 
  1172 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1173 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1174 FAIL); can suppress it using the command Delsimps (ex_simps @
  1175 all_simps); De Morgan laws are also now included, by default;
  1176 
  1177 * improved printing of ==>  :  ~:
  1178 
  1179 * new object-logic "Sequents" adds linear logic, while replacing LK
  1180 and Modal (thanks to Sara Kalvala);
  1181 
  1182 * HOL/Auth: correctness proofs for authentication protocols;
  1183 
  1184 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1185 examples on HOL/Auth);
  1186 
  1187 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1188 the rewriter and classical reasoner simultaneously;
  1189 
  1190 * function uresult no longer returns theorems in "standard" format;
  1191 regain previous version by: val uresult = standard o uresult;
  1192 
  1193 
  1194 
  1195 New in Isabelle94-6
  1196 -------------------
  1197 
  1198 * oracles -- these establish an interface between Isabelle and trusted
  1199 external reasoners, which may deliver results as theorems;
  1200 
  1201 * proof objects (in particular record all uses of oracles);
  1202 
  1203 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1204 
  1205 * "constdefs" section in theory files;
  1206 
  1207 * "primrec" section (HOL) no longer requires names;
  1208 
  1209 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1210 
  1211 
  1212 
  1213 New in Isabelle94-5
  1214 -------------------
  1215 
  1216 * reduced space requirements;
  1217 
  1218 * automatic HTML generation from theories;
  1219 
  1220 * theory files no longer require "..." (quotes) around most types;
  1221 
  1222 * new examples, including two proofs of the Church-Rosser theorem;
  1223 
  1224 * non-curried (1994) version of HOL is no longer distributed;
  1225 
  1226 
  1227 
  1228 New in Isabelle94-4
  1229 -------------------
  1230 
  1231 * greatly reduced space requirements;
  1232 
  1233 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1234 
  1235 * searchable theorem database (see the section "Retrieving theorems" on
  1236 page 8 of the Reference Manual);
  1237 
  1238 * new examples, including Grabczewski's monumental case study of the
  1239 Axiom of Choice;
  1240 
  1241 * The previous version of HOL renamed to Old_HOL;
  1242 
  1243 * The new version of HOL (previously called CHOL) uses a curried syntax
  1244 for functions.  Application looks like f a b instead of f(a,b);
  1245 
  1246 * Mutually recursive inductive definitions finally work in HOL;
  1247 
  1248 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1249 translates to the operator "split";
  1250 
  1251 
  1252 
  1253 New in Isabelle94-3
  1254 -------------------
  1255 
  1256 * new infix operator, addss, allowing the classical reasoner to
  1257 perform simplification at each step of its search.  Example:
  1258         fast_tac (cs addss ss)
  1259 
  1260 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1261 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1262 look like (a,b) instead of <a,b>;
  1263 
  1264 * PLEASE NOTE: CHOL will eventually replace HOL!
  1265 
  1266 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1267 It translates to the operator "split".  A new theory of integers is available;
  1268 
  1269 * In ZF, integer numerals now denote two's-complement binary integers.
  1270 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1271 
  1272 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1273 of the Axiom of Choice;
  1274 
  1275 
  1276 
  1277 New in Isabelle94-2
  1278 -------------------
  1279 
  1280 * Significantly faster resolution;
  1281 
  1282 * the different sections in a .thy file can now be mixed and repeated
  1283 freely;
  1284 
  1285 * Database of theorems for FOL, HOL and ZF.  New
  1286 commands including qed, qed_goal and bind_thm store theorems in the database.
  1287 
  1288 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1289 a given theory (thms_of), or find out what theory a theorem was proved in
  1290 (theory_of_thm);
  1291 
  1292 * Bugs fixed in the inductive definition and datatype packages;
  1293 
  1294 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1295 and HOL_dup_cs obsolete;
  1296 
  1297 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1298 have been removed;
  1299 
  1300 * Simpler definition of function space in ZF;
  1301 
  1302 * new results about cardinal and ordinal arithmetic in ZF;
  1303 
  1304 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1305 types;
  1306 
  1307 
  1308 $Id$