NEWS
author wenzelm
Sat Apr 01 20:17:51 2000 +0200 (2000-04-01)
changeset 8655 16906e600c9a
parent 8626 76e3913ff421
child 8673 987ea1a559d0
permissions -rw-r--r--
recdef: admit name and atts;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** Overview of INCOMPATIBILITIES (see below for more details) ***
     8 
     9 * HOL: the constant for f``x is now "image" rather than "op ``".
    10 
    11 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
    12 
    13 * HOL: simplification no longer dives into case-expressions
    14 
    15 * HOL: the recursion equations generated by 'recdef' are now called
    16 f.simps instead of f.rules;
    17 
    18 * ML: PureThy.add_thms/add_axioms/add_defs return theorems as well;
    19 
    20 
    21 *** Document preparation ***
    22 
    23 * isatool mkdir provides easy setup of Isabelle session directories,
    24 including proper document sources;
    25 
    26 * generated LaTeX sources are now deleted after successful run
    27 (isatool document -c); may retain a copy somewhere else via -D option
    28 of isatool usedir;
    29 
    30 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
    31 style files, achieving self-contained LaTeX sources;
    32 
    33 * old-style theories now produce (crude) LaTeX output as well;
    34 
    35 
    36 *** Isar ***
    37 
    38 * Pure: local results and corresponding term bindings are now subject
    39 to Hindley-Milner polymorphism (similar to ML); this accommodates
    40 incremental type-inference nicely;
    41 
    42 * Pure: new 'obtain' language element supports generalized existence
    43 reasoning;
    44 
    45 * Pure: new calculational elements 'moreover' and 'ultimately' support
    46 plain accumulation of results, without applying any rules yet;
    47 
    48 * Pure: scalable support for case-analysis type proofs: new 'case'
    49 language element refers to local contexts symbolically, as produced by
    50 certain proof methods; internally, case names are attached to theorems
    51 as "tags";
    52 
    53 * Pure now provides its own version of intro/elim/dest attributes;
    54 useful for building new logics, but beware of confusion with the
    55 Provers/classical ones;
    56 
    57 * Provers: splitter support (via 'split' attribute and 'simp' method
    58 modifier); 'simp' method: 'only:' modifier removes loopers as well
    59 (including splits);
    60 
    61 * HOL: new proof method 'cases' and improved version of 'induct' now
    62 support named cases; major packages (inductive, datatype, primrec,
    63 recdef) support case names and properly name parameters;
    64 
    65 * HOL: removed 'case_split' thm binding, should use 'cases' proof
    66 method anyway;
    67 
    68 * names of theorems etc. may be natural numbers as well;
    69 
    70 * Provers: intro/elim/dest attributes: changed ! / !! flags to ? / ??;
    71 
    72 * 'pr' command: optional goals_limit argument;
    73 
    74 * diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
    75 additional print modes to be specified; e.g. "pr(latex)" will print
    76 proof state according to the Isabelle LaTeX style;
    77 
    78 * improved support for emulating tactic scripts, including proof
    79 methods 'tactic', 'res_inst_tac' etc., 'subgoal_tac', and 'case_tac' /
    80 'induct_tac' (for HOL datatypes);
    81 
    82 
    83 
    84 *** HOL ***
    85 
    86 * HOL/Algebra: new theory of rings and univariate polynomials, by
    87 Clemens Ballarin;
    88 
    89 * HOL/record: fixed select-update simplification procedure to handle
    90 extended records as well; admit "r" as field name;
    91 
    92 * HOL/ex: new theory Factorization proving the Fundamental Theorem of
    93 Arithmetic, by Thomas M Rasmussen;
    94 
    95 * HOL/ex/Multiquote: multiple nested quotations and anti-quotations --
    96 basically a generalized version of de-Bruijn representation; very
    97 useful in avoiding lifting all operations;
    98 
    99 * new version of "case_tac" subsumes both boolean case split and
   100 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   101 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   102 
   103 * simplification no longer dives into case-expressions: only the selector
   104 expression is simplified, but not the remaining arms. To enable full
   105 simplification of case-expressions for datatype t, you need to remove
   106 t.weak_case_cong from the simpset, either permanently
   107 (Delcongs[thm"t.weak_case_cong"];) or locally (delcongs [...]).
   108 
   109 * the recursion equations generated by 'recdef' for function 'f' are
   110 now called f.simps instead of f.rules; if all termination conditions
   111 are proved automatically, these simplification rules are added to the
   112 simpset, as in primrec; rules may be named individually as well,
   113 resulting in a separate list of theorems for each equation;
   114 
   115 
   116 *** General ***
   117 
   118 * compression of ML heaps images may now be controlled via -c option
   119 of isabelle and isatool usedir (currently only observed by Poly/ML);
   120 
   121 * ML: new combinators |>> and |>>> for incremental transformations
   122 with secondary results (e.g. certain theory extensions):
   123 
   124 
   125 
   126 New in Isabelle99 (October 1999)
   127 --------------------------------
   128 
   129 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   130 
   131 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   132 are no longer simplified.  (This allows the simplifier to unfold recursive
   133 functional programs.)  To restore the old behaviour, declare
   134 
   135     Delcongs [if_weak_cong];
   136 
   137 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   138 complement;
   139 
   140 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   141 
   142 * HOL/datatype: mutual_induct_tac no longer exists --
   143   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   144 
   145 * HOL/typedef: fixed type inference for representing set; type
   146 arguments now have to occur explicitly on the rhs as type constraints;
   147 
   148 * ZF: The con_defs part of an inductive definition may no longer refer
   149 to constants declared in the same theory;
   150 
   151 * HOL, ZF: the function mk_cases, generated by the inductive
   152 definition package, has lost an argument.  To simplify its result, it
   153 uses the default simpset instead of a supplied list of theorems.
   154 
   155 * HOL/List: the constructors of type list are now Nil and Cons;
   156 
   157 * Simplifier: the type of the infix ML functions
   158 	setSSolver addSSolver setSolver addSolver
   159 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   160 for packaging solvers. A solver is created via
   161 	mk_solver: string -> (thm list -> int -> tactic) -> solver
   162 where the string argument is only a comment.
   163 
   164 
   165 *** Proof tools ***
   166 
   167 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   168 decision procedure for linear arithmetic. Currently it is used for
   169 types `nat', `int', and `real' in HOL (see below); it can, should and
   170 will be instantiated for other types and logics as well.
   171 
   172 * The simplifier now accepts rewrite rules with flexible heads, eg
   173      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   174   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   175   matching.
   176 
   177 
   178 *** General ***
   179 
   180 * New Isabelle/Isar subsystem provides an alternative to traditional
   181 tactical theorem proving; together with the ProofGeneral/isar user
   182 interface it offers an interactive environment for developing human
   183 readable proof documents (Isar == Intelligible semi-automated
   184 reasoning); for further information see isatool doc isar-ref,
   185 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   186 
   187 * improved presentation of theories: better HTML markup (including
   188 colors), graph views in several sizes; isatool usedir now provides a
   189 proper interface for user theories (via -P option); actual document
   190 preparation based on (PDF)LaTeX is available as well (for new-style
   191 theories only); see isatool doc system for more information;
   192 
   193 * native support for Proof General, both for classic Isabelle and
   194 Isabelle/Isar;
   195 
   196 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   197 using the graph browser tool;
   198 
   199 * Isabelle manuals now also available as PDF;
   200 
   201 * theory loader rewritten from scratch (may not be fully
   202 bug-compatible); old loadpath variable has been replaced by show_path,
   203 add_path, del_path, reset_path functions; new operations such as
   204 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   205 isatool doc ref);
   206 
   207 * improved isatool install: option -k creates KDE application icon,
   208 option -p DIR installs standalone binaries;
   209 
   210 * added ML_PLATFORM setting (useful for cross-platform installations);
   211 more robust handling of platform specific ML images for SML/NJ;
   212 
   213 * the settings environment is now statically scoped, i.e. it is never
   214 created again in sub-processes invoked from isabelle, isatool, or
   215 Isabelle;
   216 
   217 * path element specification '~~' refers to '$ISABELLE_HOME';
   218 
   219 * in locales, the "assumes" and "defines" parts may be omitted if
   220 empty;
   221 
   222 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   223 long arrows);
   224 
   225 * new print_mode "HTML";
   226 
   227 * new flag show_tags controls display of tags of theorems (which are
   228 basically just comments that may be attached by some tools);
   229 
   230 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   231 mode and goal output format:
   232 
   233 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   234 244c244
   235 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   236 ---
   237 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   238 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   239 181c181
   240 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   241 ---
   242 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   243 
   244 * function bind_thms stores lists of theorems (cf. bind_thm);
   245 
   246 * new shorthand tactics ftac, eatac, datac, fatac;
   247 
   248 * qed (and friends) now accept "" as result name; in that case the
   249 theorem is not stored, but proper checks and presentation of the
   250 result still apply;
   251 
   252 * theorem database now also indexes constants "Trueprop", "all",
   253 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   254 
   255 
   256 *** HOL ***
   257 
   258 ** HOL arithmetic **
   259 
   260 * There are now decision procedures for linear arithmetic over nat and
   261 int:
   262 
   263 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   264 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   265 are treated as atomic; subformulae not involving type `nat' or `int'
   266 are ignored; quantified subformulae are ignored unless they are
   267 positive universal or negative existential. The tactic has to be
   268 invoked by hand and can be a little bit slow. In particular, the
   269 running time is exponential in the number of occurrences of `min' and
   270 `max', and `-' on `nat'.
   271 
   272 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   273 (negated) (in)equalities among the premises and the conclusion into
   274 account (i.e. no compound formulae) and does not know about `min' and
   275 `max', and `-' on `nat'. It is fast and is used automatically by the
   276 simplifier.
   277 
   278 NB: At the moment, these decision procedures do not cope with mixed
   279 nat/int formulae where the two parts interact, such as `m < n ==>
   280 int(m) < int(n)'.
   281 
   282 * HOL/Numeral provides a generic theory of numerals (encoded
   283 efficiently as bit strings); setup for types nat/int/real is in place;
   284 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   285 int, existing theories and proof scripts may require a few additional
   286 type constraints;
   287 
   288 * integer division and remainder can now be performed on constant
   289 arguments;
   290 
   291 * many properties of integer multiplication, division and remainder
   292 are now available;
   293 
   294 * An interface to the Stanford Validity Checker (SVC) is available through the
   295 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   296 are proved automatically.  SVC must be installed separately, and its results
   297 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   298 invocation of the underlying oracle).  For SVC see
   299   http://verify.stanford.edu/SVC
   300 
   301 * IsaMakefile: the HOL-Real target now builds an actual image;
   302 
   303 
   304 ** HOL misc **
   305 
   306 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   307 (in Isabelle/Isar) -- by Gertrud Bauer;
   308 
   309 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   310 analysis for assembly languages with subtypes;
   311 
   312 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   313 -- avoids syntactic ambiguities and treats state, transition, and
   314 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   315 changed syntax and (many) tactics;
   316 
   317 * HOL/inductive: Now also handles more general introduction rules such
   318   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   319   theorems are now maintained within the theory (maintained via the
   320   "mono" attribute);
   321 
   322 * HOL/datatype: Now also handles arbitrarily branching datatypes
   323   (using function types) such as
   324 
   325   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   326 
   327 * HOL/record: record_simproc (part of the default simpset) takes care
   328 of selectors applied to updated records; record_split_tac is no longer
   329 part of the default claset; update_defs may now be removed from the
   330 simpset in many cases; COMPATIBILITY: old behavior achieved by
   331 
   332   claset_ref () := claset() addSWrapper record_split_wrapper;
   333   Delsimprocs [record_simproc]
   334 
   335 * HOL/typedef: fixed type inference for representing set; type
   336 arguments now have to occur explicitly on the rhs as type constraints;
   337 
   338 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   339 names rather than an ML expression;
   340 
   341 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   342 supplied later.  Program schemes can be defined, such as
   343     "While B C s = (if B s then While B C (C s) else s)"
   344 where the well-founded relation can be chosen after B and C have been given.
   345 
   346 * HOL/List: the constructors of type list are now Nil and Cons;
   347 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   348 course, ML tools referring to List.list.op # etc. have to be adapted;
   349 
   350 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   351 disabled by default; run isabelle with option -m HOL to get back to
   352 the original Gordon/HOL-style output;
   353 
   354 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   355 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   356 
   357 * HOL basic syntax simplified (more orthogonal): all variants of
   358 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   359 Eps operator is provided as well: "SOME x. P[x]";
   360 
   361 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   362 
   363 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   364 thus available for user theories;
   365 
   366 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   367 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   368 time;
   369 
   370 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   371 several times and then mp;
   372 
   373 
   374 *** LK ***
   375 
   376 * the notation <<...>> is now available as a notation for sequences of
   377 formulas;
   378 
   379 * the simplifier is now installed
   380 
   381 * the axiom system has been generalized (thanks to Soren Heilmann) 
   382 
   383 * the classical reasoner now has a default rule database
   384 
   385 
   386 *** ZF ***
   387 
   388 * new primrec section allows primitive recursive functions to be given
   389 directly (as in HOL) over datatypes and the natural numbers;
   390 
   391 * new tactics induct_tac and exhaust_tac for induction (or case
   392 analysis) over datatypes and the natural numbers;
   393 
   394 * the datatype declaration of type T now defines the recursor T_rec;
   395 
   396 * simplification automatically does freeness reasoning for datatype
   397 constructors;
   398 
   399 * automatic type-inference, with AddTCs command to insert new
   400 type-checking rules;
   401 
   402 * datatype introduction rules are now added as Safe Introduction rules
   403 to the claset;
   404 
   405 * the syntax "if P then x else y" is now available in addition to
   406 if(P,x,y);
   407 
   408 
   409 *** Internal programming interfaces ***
   410 
   411 * tuned simplifier trace output; new flag debug_simp;
   412 
   413 * structures Vartab / Termtab (instances of TableFun) offer efficient
   414 tables indexed by indexname_ord / term_ord (compatible with aconv);
   415 
   416 * AxClass.axclass_tac lost the theory argument;
   417 
   418 * tuned current_goals_markers semantics: begin / end goal avoids
   419 printing empty lines;
   420 
   421 * removed prs and prs_fn hook, which was broken because it did not
   422 include \n in its semantics, forcing writeln to add one
   423 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   424 string -> unit if you really want to output text without newline;
   425 
   426 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   427 plain output, interface builders may have to enable 'isabelle_font'
   428 mode to get Isabelle font glyphs as before;
   429 
   430 * refined token_translation interface; INCOMPATIBILITY: output length
   431 now of type real instead of int;
   432 
   433 * theory loader actions may be traced via new ThyInfo.add_hook
   434 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   435 your own database of information attached to *whole* theories -- as
   436 opposed to intra-theory data slots offered via TheoryDataFun;
   437 
   438 * proper handling of dangling sort hypotheses (at last!);
   439 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   440 extra sort hypotheses that can be witnessed from the type signature;
   441 the force_strip_shyps flag is gone, any remaining shyps are simply
   442 left in the theorem (with a warning issued by strip_shyps_warning);
   443 
   444 
   445 
   446 New in Isabelle98-1 (October 1998)
   447 ----------------------------------
   448 
   449 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   450 
   451 * several changes of automated proof tools;
   452 
   453 * HOL: major changes to the inductive and datatype packages, including
   454 some minor incompatibilities of theory syntax;
   455 
   456 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   457 called `inj_on';
   458 
   459 * HOL: removed duplicate thms in Arith:
   460   less_imp_add_less  should be replaced by  trans_less_add1
   461   le_imp_add_le      should be replaced by  trans_le_add1
   462 
   463 * HOL: unary minus is now overloaded (new type constraints may be
   464 required);
   465 
   466 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   467 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   468 now taken as an integer constant.
   469 
   470 * Pure: ML function 'theory_of' renamed to 'theory';
   471 
   472 
   473 *** Proof tools ***
   474 
   475 * Simplifier:
   476   1. Asm_full_simp_tac is now more aggressive.
   477      1. It will sometimes reorient premises if that increases their power to
   478         simplify.
   479      2. It does no longer proceed strictly from left to right but may also
   480         rotate premises to achieve further simplification.
   481      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   482      old Asm_full_simp_tac in that it does not rotate premises.
   483   2. The simplifier now knows a little bit about nat-arithmetic.
   484 
   485 * Classical reasoner: wrapper mechanism for the classical reasoner now
   486 allows for selected deletion of wrappers, by introduction of names for
   487 wrapper functionals.  This implies that addbefore, addSbefore,
   488 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   489 and that adding two tactics with the same name overwrites the first
   490 one (emitting a warning).
   491   type wrapper = (int -> tactic) -> (int -> tactic)
   492   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   493   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   494   delWrapper, delSWrapper: claset *  string            -> claset
   495   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   496 
   497 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   498 semantics; addbefore now affects only the unsafe part of step_tac
   499 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   500 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   501 by Force_tac;
   502 
   503 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   504 compWrapper; added safe wrapper (and access functions for it);
   505 
   506 * HOL/split_all_tac is now much faster and fails if there is nothing
   507 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   508 and the names of the automatically generated variables have changed.
   509 split_all_tac has moved within claset() from unsafe wrappers to safe
   510 wrappers, which means that !!-bound variables are split much more
   511 aggressively, and safe_tac and clarify_tac now split such variables.
   512 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   513 Note: the same holds for record_split_tac, which does the job of
   514 split_all_tac for record fields.
   515 
   516 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   517 permanently to the default simpset using Addsplits just like
   518 Addsimps. They can be removed via Delsplits just like
   519 Delsimps. Lower-case versions are also available.
   520 
   521 * HOL/Simplifier: The rule split_if is now part of the default
   522 simpset. This means that the simplifier will eliminate all occurrences
   523 of if-then-else in the conclusion of a goal. To prevent this, you can
   524 either remove split_if completely from the default simpset by
   525 `Delsplits [split_if]' or remove it in a specific call of the
   526 simplifier using `... delsplits [split_if]'.  You can also add/delete
   527 other case splitting rules to/from the default simpset: every datatype
   528 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   529 t is the name of the datatype).
   530 
   531 * Classical reasoner / Simplifier combination: new force_tac (and
   532 derivatives Force_tac, force) combines rewriting and classical
   533 reasoning (and whatever other tools) similarly to auto_tac, but is
   534 aimed to solve the given subgoal completely.
   535 
   536 
   537 *** General ***
   538 
   539 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   540 and `goalw': the theory is no longer needed as an explicit argument -
   541 the current theory context is used; assumptions are no longer returned
   542 at the ML-level unless one of them starts with ==> or !!; it is
   543 recommended to convert to these new commands using isatool fixgoal
   544 (backup your sources first!);
   545 
   546 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   547 the current theory context, and 'theory' to lookup stored theories;
   548 
   549 * new theory section 'locale' for declaring constants, assumptions and
   550 definitions that have local scope;
   551 
   552 * new theory section 'nonterminals' for purely syntactic types;
   553 
   554 * new theory section 'setup' for generic ML setup functions
   555 (e.g. package initialization);
   556 
   557 * the distribution now includes Isabelle icons: see
   558 lib/logo/isabelle-{small,tiny}.xpm;
   559 
   560 * isatool install - install binaries with absolute references to
   561 ISABELLE_HOME/bin;
   562 
   563 * isatool logo -- create instances of the Isabelle logo (as EPS);
   564 
   565 * print mode 'emacs' reserved for Isamode;
   566 
   567 * support multiple print (ast) translations per constant name;
   568 
   569 * theorems involving oracles are now printed with a suffixed [!];
   570 
   571 
   572 *** HOL ***
   573 
   574 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   575 
   576 * HOL/inductive package reorganized and improved: now supports mutual
   577 definitions such as
   578 
   579   inductive EVEN ODD
   580     intrs
   581       null "0 : EVEN"
   582       oddI "n : EVEN ==> Suc n : ODD"
   583       evenI "n : ODD ==> Suc n : EVEN"
   584 
   585 new theorem list "elims" contains an elimination rule for each of the
   586 recursive sets; inductive definitions now handle disjunctive premises
   587 correctly (also ZF);
   588 
   589 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   590 "mutual_induct" no longer exists - the induction rule is always
   591 contained in "induct";
   592 
   593 
   594 * HOL/datatype package re-implemented and greatly improved: now
   595 supports mutually recursive datatypes such as
   596 
   597   datatype
   598     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   599             | SUM ('a aexp) ('a aexp)
   600             | DIFF ('a aexp) ('a aexp)
   601             | NUM 'a
   602   and
   603     'a bexp = LESS ('a aexp) ('a aexp)
   604             | AND ('a bexp) ('a bexp)
   605             | OR ('a bexp) ('a bexp)
   606 
   607 as well as indirectly recursive datatypes such as
   608 
   609   datatype
   610     ('a, 'b) term = Var 'a
   611                   | App 'b ((('a, 'b) term) list)
   612 
   613 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   614 induction on mutually / indirectly recursive datatypes.
   615 
   616 Primrec equations are now stored in theory and can be accessed via
   617 <function_name>.simps.
   618 
   619 INCOMPATIBILITIES:
   620 
   621   - Theories using datatypes must now have theory Datatype as an
   622     ancestor.
   623   - The specific <typename>.induct_tac no longer exists - use the
   624     generic induct_tac instead.
   625   - natE has been renamed to nat.exhaust - use exhaust_tac
   626     instead of res_inst_tac ... natE. Note that the variable
   627     names in nat.exhaust differ from the names in natE, this
   628     may cause some "fragile" proofs to fail.
   629   - The theorems split_<typename>_case and split_<typename>_case_asm
   630     have been renamed to <typename>.split and <typename>.split_asm.
   631   - Since default sorts of type variables are now handled correctly,
   632     some datatype definitions may have to be annotated with explicit
   633     sort constraints.
   634   - Primrec definitions no longer require function name and type
   635     of recursive argument.
   636 
   637 Consider using isatool fixdatatype to adapt your theories and proof
   638 scripts to the new package (backup your sources first!).
   639 
   640 
   641 * HOL/record package: considerably improved implementation; now
   642 includes concrete syntax for record types, terms, updates; theorems
   643 for surjective pairing and splitting !!-bound record variables; proof
   644 support is as follows:
   645 
   646   1) standard conversions (selectors or updates applied to record
   647 constructor terms) are part of the standard simpset;
   648 
   649   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   650 made part of standard simpset and claset via addIffs;
   651 
   652   3) a tactic for record field splitting (record_split_tac) is part of
   653 the standard claset (addSWrapper);
   654 
   655 To get a better idea about these rules you may retrieve them via
   656 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   657 the name of your record type.
   658 
   659 The split tactic 3) conceptually simplifies by the following rule:
   660 
   661   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   662 
   663 Thus any record variable that is bound by meta-all will automatically
   664 blow up into some record constructor term, consequently the
   665 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   666 solve record problems automatically.
   667 
   668 
   669 * reorganized the main HOL image: HOL/Integ and String loaded by
   670 default; theory Main includes everything;
   671 
   672 * automatic simplification of integer sums and comparisons, using cancellation;
   673 
   674 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   675 
   676 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   677 
   678 * many new identities for unions, intersections, set difference, etc.;
   679 
   680 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   681 called split_if, split_split, split_sum_case and split_nat_case (to go
   682 with add/delsplits);
   683 
   684 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   685 (?x::unit) = (); this is made part of the default simpset, which COULD
   686 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   687 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   688 unit_abs_eta_conv is added in order to counter the effect of
   689 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   690 %u.f();
   691 
   692 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   693 makes more sense);
   694 
   695 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   696   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   697   disjointness reasoning but breaking a few old proofs.
   698 
   699 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   700 to 'converse' from 'inverse' (for compatibility with ZF and some
   701 literature);
   702 
   703 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   704 the well-founded relation;
   705 
   706 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   707     Compl A.  The "Compl" syntax remains available as input syntax for this
   708     release ONLY.
   709 
   710 * HOL/Update: new theory of function updates:
   711     f(a:=b) == %x. if x=a then b else f x
   712 may also be iterated as in f(a:=b,c:=d,...);
   713 
   714 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   715 
   716 * HOL/List:
   717   - new function list_update written xs[i:=v] that updates the i-th
   718     list position. May also be iterated as in xs[i:=a,j:=b,...].
   719   - new function `upt' written [i..j(] which generates the list
   720     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   721     bound write [i..j], which is a shorthand for [i..j+1(].
   722   - new lexicographic orderings and corresponding wellfoundedness theorems.
   723 
   724 * HOL/Arith:
   725   - removed 'pred' (predecessor) function;
   726   - generalized some theorems about n-1;
   727   - many new laws about "div" and "mod";
   728   - new laws about greatest common divisors (see theory ex/Primes);
   729 
   730 * HOL/Relation: renamed the relational operator r^-1 "converse"
   731 instead of "inverse";
   732 
   733 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   734   of the multiset ordering;
   735 
   736 * directory HOL/Real: a construction of the reals using Dedekind cuts
   737   (not included by default);
   738 
   739 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   740 
   741 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   742   programs, i.e. different program variables may have different types.
   743 
   744 * calling (stac rew i) now fails if "rew" has no effect on the goal
   745   [previously, this check worked only if the rewrite rule was unconditional]
   746   Now rew can involve either definitions or equalities (either == or =).
   747 
   748 
   749 *** ZF ***
   750 
   751 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   752   only the theorems proved on ZF.ML;
   753 
   754 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   755   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   756   disjointness reasoning but breaking a few old proofs.
   757 
   758 * ZF/Update: new theory of function updates
   759     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   760   may also be iterated as in f(a:=b,c:=d,...);
   761 
   762 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   763 
   764 * calling (stac rew i) now fails if "rew" has no effect on the goal
   765   [previously, this check worked only if the rewrite rule was unconditional]
   766   Now rew can involve either definitions or equalities (either == or =).
   767 
   768 * case_tac provided for compatibility with HOL
   769     (like the old excluded_middle_tac, but with subgoals swapped)
   770 
   771 
   772 *** Internal programming interfaces ***
   773 
   774 * Pure: several new basic modules made available for general use, see
   775 also src/Pure/README;
   776 
   777 * improved the theory data mechanism to support encapsulation (data
   778 kind name replaced by private Object.kind, acting as authorization
   779 key); new type-safe user interface via functor TheoryDataFun; generic
   780 print_data function becomes basically useless;
   781 
   782 * removed global_names compatibility flag -- all theory declarations
   783 are qualified by default;
   784 
   785 * module Pure/Syntax now offers quote / antiquote translation
   786 functions (useful for Hoare logic etc. with implicit dependencies);
   787 see HOL/ex/Antiquote for an example use;
   788 
   789 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   790 cterm -> thm;
   791 
   792 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   793 subgoal;
   794 
   795 * Display.print_goals function moved to Locale.print_goals;
   796 
   797 * standard print function for goals supports current_goals_markers
   798 variable for marking begin of proof, end of proof, start of goal; the
   799 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   800 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   801 for example;
   802 
   803 
   804 
   805 New in Isabelle98 (January 1998)
   806 --------------------------------
   807 
   808 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   809 
   810 * changed lexical syntax of terms / types: dots made part of long
   811 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   812 
   813 * simpset (and claset) reference variable replaced by functions
   814 simpset / simpset_ref;
   815 
   816 * no longer supports theory aliases (via merge) and non-trivial
   817 implicit merge of thms' signatures;
   818 
   819 * most internal names of constants changed due to qualified names;
   820 
   821 * changed Pure/Sequence interface (see Pure/seq.ML);
   822 
   823 
   824 *** General Changes ***
   825 
   826 * hierachically structured name spaces (for consts, types, axms, thms
   827 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   828 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   829 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   830 long_names for fully qualified output names; NOTE: ML programs
   831 (special tactics, packages etc.) referring to internal names may have
   832 to be adapted to cope with fully qualified names; in case of severe
   833 backward campatibility problems try setting 'global_names' at compile
   834 time to have enrything declared within a flat name space; one may also
   835 fine tune name declarations in theories via the 'global' and 'local'
   836 section;
   837 
   838 * reimplemented the implicit simpset and claset using the new anytype
   839 data filed in signatures; references simpset:simpset ref etc. are
   840 replaced by functions simpset:unit->simpset and
   841 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   842 to patch your ML files accordingly;
   843 
   844 * HTML output now includes theory graph data for display with Java
   845 applet or isatool browser; data generated automatically via isatool
   846 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   847 
   848 * defs may now be conditional; improved rewrite_goals_tac to handle
   849 conditional equations;
   850 
   851 * defs now admits additional type arguments, using TYPE('a) syntax;
   852 
   853 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   854 creates a new theory node; implicit merge of thms' signatures is
   855 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   856 transfer:theory->thm->thm in (rare) cases;
   857 
   858 * improved handling of draft signatures / theories; draft thms (and
   859 ctyps, cterms) are automatically promoted to real ones;
   860 
   861 * slightly changed interfaces for oracles: admit many per theory, named
   862 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   863 
   864 * print_goals: optional output of const types (set show_consts and
   865 show_types);
   866 
   867 * improved output of warnings (###) and errors (***);
   868 
   869 * subgoal_tac displays a warning if the new subgoal has type variables;
   870 
   871 * removed old README and Makefiles;
   872 
   873 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   874 
   875 * removed obsolete init_pps and init_database;
   876 
   877 * deleted the obsolete tactical STATE, which was declared by
   878     fun STATE tacfun st = tacfun st st;
   879 
   880 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   881 (which abbreviates $HOME);
   882 
   883 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   884 use isatool fixseq to adapt your ML programs (this works for fully
   885 qualified references to the Sequence structure only!);
   886 
   887 * use_thy no longer requires writable current directory; it always
   888 reloads .ML *and* .thy file, if either one is out of date;
   889 
   890 
   891 *** Classical Reasoner ***
   892 
   893 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   894 tactics that use classical reasoning to simplify a subgoal without
   895 splitting it into several subgoals;
   896 
   897 * Safe_tac: like safe_tac but uses the default claset;
   898 
   899 
   900 *** Simplifier ***
   901 
   902 * added simplification meta rules:
   903     (asm_)(full_)simplify: simpset -> thm -> thm;
   904 
   905 * simplifier.ML no longer part of Pure -- has to be loaded by object
   906 logics (again);
   907 
   908 * added prems argument to simplification procedures;
   909 
   910 * HOL, FOL, ZF: added infix function `addsplits':
   911   instead of `<simpset> setloop (split_tac <thms>)'
   912   you can simply write `<simpset> addsplits <thms>'
   913 
   914 
   915 *** Syntax ***
   916 
   917 * TYPE('a) syntax for type reflection terms;
   918 
   919 * no longer handles consts with name "" -- declare as 'syntax' instead;
   920 
   921 * pretty printer: changed order of mixfix annotation preference (again!);
   922 
   923 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   924 
   925 
   926 *** HOL ***
   927 
   928 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   929   with `addloop' of the simplifier to faciliate case splitting in premises.
   930 
   931 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   932 
   933 * HOL/Auth: new protocol proofs including some for the Internet
   934   protocol TLS;
   935 
   936 * HOL/Map: new theory of `maps' a la VDM;
   937 
   938 * HOL/simplifier: simplification procedures nat_cancel_sums for
   939 cancelling out common nat summands from =, <, <= (in)equalities, or
   940 differences; simplification procedures nat_cancel_factor for
   941 cancelling common factor from =, <, <= (in)equalities over natural
   942 sums; nat_cancel contains both kinds of procedures, it is installed by
   943 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   944 
   945 * HOL/simplifier: terms of the form
   946   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   947   are rewritten to
   948   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   949   and those of the form
   950   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   951   are rewritten to
   952   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   953 
   954 * HOL/datatype
   955   Each datatype `t' now comes with a theorem `split_t_case' 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 
   963   and a theorem `split_t_case_asm' of the form
   964 
   965   P(t_case f1 ... fn x) =
   966     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   967         ...
   968        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   969      )
   970   which can be added to a simpset via `addsplits'. The existing theorems
   971   expand_list_case and expand_option_case have been renamed to
   972   split_list_case and split_option_case.
   973 
   974 * HOL/Arithmetic:
   975   - `pred n' is automatically converted to `n-1'.
   976     Users are strongly encouraged not to use `pred' any longer,
   977     because it will disappear altogether at some point.
   978   - Users are strongly encouraged to write "0 < n" rather than
   979     "n ~= 0". Theorems and proof tools have been modified towards this
   980     `standard'.
   981 
   982 * HOL/Lists:
   983   the function "set_of_list" has been renamed "set" (and its theorems too);
   984   the function "nth" now takes its arguments in the reverse order and
   985   has acquired the infix notation "!" as in "xs!n".
   986 
   987 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   988 
   989 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   990   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   991 
   992 * HOL/record: extensible records with schematic structural subtyping
   993 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   994 still lacks various theorems and concrete record syntax;
   995 
   996 
   997 *** HOLCF ***
   998 
   999 * removed "axioms" and "generated by" sections;
  1000 
  1001 * replaced "ops" section by extended "consts" section, which is capable of
  1002   handling the continuous function space "->" directly;
  1003 
  1004 * domain package:
  1005   . proves theorems immediately and stores them in the theory,
  1006   . creates hierachical name space,
  1007   . now uses normal mixfix annotations (instead of cinfix...),
  1008   . minor changes to some names and values (for consistency),
  1009   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1010   . separator between mutual domain defs: changed "," to "and",
  1011   . improved handling of sort constraints;  now they have to
  1012     appear on the left-hand side of the equations only;
  1013 
  1014 * fixed LAM <x,y,zs>.b syntax;
  1015 
  1016 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1017 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1018 
  1019 
  1020 *** FOL and ZF ***
  1021 
  1022 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1023   with `addloop' of the simplifier to faciliate case splitting in premises.
  1024 
  1025 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1026 in HOL, they strip ALL and --> from proved theorems;
  1027 
  1028 
  1029 
  1030 New in Isabelle94-8 (May 1997)
  1031 ------------------------------
  1032 
  1033 *** General Changes ***
  1034 
  1035 * new utilities to build / run / maintain Isabelle etc. (in parts
  1036 still somewhat experimental); old Makefiles etc. still functional;
  1037 
  1038 * new 'Isabelle System Manual';
  1039 
  1040 * INSTALL text, together with ./configure and ./build scripts;
  1041 
  1042 * reimplemented type inference for greater efficiency, better error
  1043 messages and clean internal interface;
  1044 
  1045 * prlim command for dealing with lots of subgoals (an easier way of
  1046 setting goals_limit);
  1047 
  1048 
  1049 *** Syntax ***
  1050 
  1051 * supports alternative (named) syntax tables (parser and pretty
  1052 printer); internal interface is provided by add_modesyntax(_i);
  1053 
  1054 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1055 be used in conjunction with the Isabelle symbol font; uses the
  1056 "symbols" syntax table;
  1057 
  1058 * added token_translation interface (may translate name tokens in
  1059 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1060 the current print_mode); IMPORTANT: user print translation functions
  1061 are responsible for marking newly introduced bounds
  1062 (Syntax.mark_boundT);
  1063 
  1064 * token translations for modes "xterm" and "xterm_color" that display
  1065 names in bold, underline etc. or colors (which requires a color
  1066 version of xterm);
  1067 
  1068 * infixes may now be declared with names independent of their syntax;
  1069 
  1070 * added typed_print_translation (like print_translation, but may
  1071 access type of constant);
  1072 
  1073 
  1074 *** Classical Reasoner ***
  1075 
  1076 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1077 some limitations.  Blast_tac...
  1078   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1079   + ignores elimination rules that don't have the correct format
  1080         (the conclusion MUST be a formula variable)
  1081   + ignores types, which can make HOL proofs fail
  1082   + rules must not require higher-order unification, e.g. apply_type in ZF
  1083     [message "Function Var's argument not a bound variable" relates to this]
  1084   + its proof strategy is more general but can actually be slower
  1085 
  1086 * substitution with equality assumptions no longer permutes other
  1087 assumptions;
  1088 
  1089 * minor changes in semantics of addafter (now called addaltern); renamed
  1090 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1091 (and access functions for it);
  1092 
  1093 * improved combination of classical reasoner and simplifier:
  1094   + functions for handling clasimpsets
  1095   + improvement of addss: now the simplifier is called _after_ the
  1096     safe steps.
  1097   + safe variant of addss called addSss: uses safe simplifications
  1098     _during_ the safe steps. It is more complete as it allows multiple
  1099     instantiations of unknowns (e.g. with slow_tac).
  1100 
  1101 *** Simplifier ***
  1102 
  1103 * added interface for simplification procedures (functions that
  1104 produce *proven* rewrite rules on the fly, depending on current
  1105 redex);
  1106 
  1107 * ordering on terms as parameter (used for ordered rewriting);
  1108 
  1109 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1110 
  1111 * the solver is now split into a safe and an unsafe part.
  1112 This should be invisible for the normal user, except that the
  1113 functions setsolver and addsolver have been renamed to setSolver and
  1114 addSolver; added safe_asm_full_simp_tac;
  1115 
  1116 
  1117 *** HOL ***
  1118 
  1119 * a generic induction tactic `induct_tac' which works for all datatypes and
  1120 also for type `nat';
  1121 
  1122 * a generic case distinction tactic `exhaust_tac' which works for all
  1123 datatypes and also for type `nat';
  1124 
  1125 * each datatype comes with a function `size';
  1126 
  1127 * patterns in case expressions allow tuple patterns as arguments to
  1128 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1129 
  1130 * primrec now also works with type nat;
  1131 
  1132 * recdef: a new declaration form, allows general recursive functions to be
  1133 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1134 
  1135 * the constant for negation has been renamed from "not" to "Not" to
  1136 harmonize with FOL, ZF, LK, etc.;
  1137 
  1138 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1139 infinite lists;
  1140 
  1141 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1142 
  1143 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1144 problems in commutative rings, using axiomatic type classes for + and *;
  1145 
  1146 * more examples in HOL/MiniML and HOL/Auth;
  1147 
  1148 * more default rewrite rules for quantifiers, union/intersection;
  1149 
  1150 * a new constant `arbitrary == @x.False';
  1151 
  1152 * HOLCF/IOA replaces old HOL/IOA;
  1153 
  1154 * HOLCF changes: derived all rules and arities
  1155   + axiomatic type classes instead of classes
  1156   + typedef instead of faking type definitions
  1157   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1158   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1159   + eliminated the types void, one, tr
  1160   + use unit lift and bool lift (with translations) instead of one and tr
  1161   + eliminated blift from Lift3.thy (use Def instead of blift)
  1162   all eliminated rules are derived as theorems --> no visible changes ;
  1163 
  1164 
  1165 *** ZF ***
  1166 
  1167 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1168 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1169 as ZF_cs addSIs [equalityI];
  1170 
  1171 
  1172 
  1173 New in Isabelle94-7 (November 96)
  1174 ---------------------------------
  1175 
  1176 * allowing negative levels (as offsets) in prlev and choplev;
  1177 
  1178 * super-linear speedup for large simplifications;
  1179 
  1180 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1181 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1182 FAIL); can suppress it using the command Delsimps (ex_simps @
  1183 all_simps); De Morgan laws are also now included, by default;
  1184 
  1185 * improved printing of ==>  :  ~:
  1186 
  1187 * new object-logic "Sequents" adds linear logic, while replacing LK
  1188 and Modal (thanks to Sara Kalvala);
  1189 
  1190 * HOL/Auth: correctness proofs for authentication protocols;
  1191 
  1192 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1193 examples on HOL/Auth);
  1194 
  1195 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1196 the rewriter and classical reasoner simultaneously;
  1197 
  1198 * function uresult no longer returns theorems in "standard" format;
  1199 regain previous version by: val uresult = standard o uresult;
  1200 
  1201 
  1202 
  1203 New in Isabelle94-6
  1204 -------------------
  1205 
  1206 * oracles -- these establish an interface between Isabelle and trusted
  1207 external reasoners, which may deliver results as theorems;
  1208 
  1209 * proof objects (in particular record all uses of oracles);
  1210 
  1211 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1212 
  1213 * "constdefs" section in theory files;
  1214 
  1215 * "primrec" section (HOL) no longer requires names;
  1216 
  1217 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1218 
  1219 
  1220 
  1221 New in Isabelle94-5
  1222 -------------------
  1223 
  1224 * reduced space requirements;
  1225 
  1226 * automatic HTML generation from theories;
  1227 
  1228 * theory files no longer require "..." (quotes) around most types;
  1229 
  1230 * new examples, including two proofs of the Church-Rosser theorem;
  1231 
  1232 * non-curried (1994) version of HOL is no longer distributed;
  1233 
  1234 
  1235 
  1236 New in Isabelle94-4
  1237 -------------------
  1238 
  1239 * greatly reduced space requirements;
  1240 
  1241 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1242 
  1243 * searchable theorem database (see the section "Retrieving theorems" on
  1244 page 8 of the Reference Manual);
  1245 
  1246 * new examples, including Grabczewski's monumental case study of the
  1247 Axiom of Choice;
  1248 
  1249 * The previous version of HOL renamed to Old_HOL;
  1250 
  1251 * The new version of HOL (previously called CHOL) uses a curried syntax
  1252 for functions.  Application looks like f a b instead of f(a,b);
  1253 
  1254 * Mutually recursive inductive definitions finally work in HOL;
  1255 
  1256 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1257 translates to the operator "split";
  1258 
  1259 
  1260 
  1261 New in Isabelle94-3
  1262 -------------------
  1263 
  1264 * new infix operator, addss, allowing the classical reasoner to
  1265 perform simplification at each step of its search.  Example:
  1266         fast_tac (cs addss ss)
  1267 
  1268 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1269 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1270 look like (a,b) instead of <a,b>;
  1271 
  1272 * PLEASE NOTE: CHOL will eventually replace HOL!
  1273 
  1274 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1275 It translates to the operator "split".  A new theory of integers is available;
  1276 
  1277 * In ZF, integer numerals now denote two's-complement binary integers.
  1278 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1279 
  1280 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1281 of the Axiom of Choice;
  1282 
  1283 
  1284 
  1285 New in Isabelle94-2
  1286 -------------------
  1287 
  1288 * Significantly faster resolution;
  1289 
  1290 * the different sections in a .thy file can now be mixed and repeated
  1291 freely;
  1292 
  1293 * Database of theorems for FOL, HOL and ZF.  New
  1294 commands including qed, qed_goal and bind_thm store theorems in the database.
  1295 
  1296 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1297 a given theory (thms_of), or find out what theory a theorem was proved in
  1298 (theory_of_thm);
  1299 
  1300 * Bugs fixed in the inductive definition and datatype packages;
  1301 
  1302 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1303 and HOL_dup_cs obsolete;
  1304 
  1305 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1306 have been removed;
  1307 
  1308 * Simpler definition of function space in ZF;
  1309 
  1310 * new results about cardinal and ordinal arithmetic in ZF;
  1311 
  1312 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1313 types;
  1314 
  1315 
  1316 $Id$