NEWS
author nipkow
Thu Jan 14 14:39:11 1999 +0100 (1999-01-14)
changeset 6132 6f049245afad
parent 6131 2d9e609abcdb
child 6141 a6922171b396
permissions -rw-r--r--
Removed superfluous arith rules from metric_simps
     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: Removed the obsolete syntax "Compl A"; use -A for set complement
    10 
    11 * ZF: The con_defs part of an inductive definition may no longer refer to 
    12   constants declared in the same theory;
    13 
    14 
    15 *** Proof tools ***
    16 
    17 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a decision
    18 procedure for linear arithmetic. Currently it is used for types `nat' and
    19 `int' in HOL (see below) but can, should and will be instantiated for other
    20 types and logics as well.
    21 
    22 
    23 *** General ***
    24 
    25 * in locales, the "assumes" and "defines" parts may be omitted if empty;
    26 
    27 * new print_mode "xsymbols" for extended symbol support 
    28   (e.g. genuiely long arrows)
    29 
    30 *** HOL ***
    31 
    32 * There are now decision procedures for linear arithmetic over nat and int:
    33 
    34 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=', `+',
    35 `-', `Suc' and numerical constants; other subterms are treated as atomic;
    36 subformulae not involving type `nat' or `int' are ignored; quantified
    37 subformulae are ignored unless they are positive universal or negative
    38 existential. The tactic has to be invoked by hand and can be a little bit
    39 slow. In particular, the running time is exponential in the number of
    40 occurrences of `-' on `nat'.
    41 
    42 2. fast_arith_tac is a cut-down version of arith_tac: it only takes (negated)
    43 (in)equalities among the premises and the conclusion into account (i.e. no
    44 compound formulae) and does not know about `-' on `nat'. It is fast and is
    45 used automatically by the simplifier.
    46 
    47 NB: At the moment, these decision procedures do not cope with mixed nat/int
    48 formulae where the two parts interact, such as `m < n ==> int(m) < int(n)'.
    49 
    50 *** Internal programming interfaces ***
    51 
    52 * tuned current_goals_markers semantics: begin / end goal avoids
    53 printing empty lines;
    54 
    55 * removed prs and prs_fn hook, which was broken because it did not
    56 include \n in its semantics, forcing writeln to add one
    57 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
    58 string -> unit if you really want to output text without newline;
    59 
    60 
    61 *** ZF ***
    62 
    63 * new primrec section allows primitive recursive functions to be given
    64   directly (as in HOL) over datatypes and the natural numbers;
    65 
    66 * new tactics induct_tac and exhaust_tac for induction (or case analysis)
    67   over datatypes and the natural numbers;
    68 
    69 * the datatype declaration of type T now defines the recursor T_rec;
    70 
    71 * The syntax "if P then x else y" is now available in addition to if(P,x,y).
    72 
    73 
    74 New in Isabelle98-1 (October 1998)
    75 ----------------------------------
    76 
    77 *** Overview of INCOMPATIBILITIES (see below for more details) ***
    78 
    79 * several changes of automated proof tools;
    80 
    81 * HOL: major changes to the inductive and datatype packages, including
    82 some minor incompatibilities of theory syntax;
    83 
    84 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
    85 called `inj_on';
    86 
    87 * HOL: removed duplicate thms in Arith:
    88   less_imp_add_less  should be replaced by  trans_less_add1
    89   le_imp_add_le      should be replaced by  trans_le_add1
    90 
    91 * HOL: unary minus is now overloaded (new type constraints may be
    92 required);
    93 
    94 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
    95 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
    96 now taken as an integer constant.
    97 
    98 * Pure: ML function 'theory_of' renamed to 'theory';
    99 
   100 
   101 *** Proof tools ***
   102 
   103 * Simplifier:
   104   1. Asm_full_simp_tac is now more aggressive.
   105      1. It will sometimes reorient premises if that increases their power to
   106         simplify.
   107      2. It does no longer proceed strictly from left to right but may also
   108         rotate premises to achieve further simplification.
   109      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   110      old Asm_full_simp_tac in that it does not rotate premises.
   111   2. The simplifier now knows a little bit about nat-arithmetic.
   112 
   113 * Classical reasoner: wrapper mechanism for the classical reasoner now
   114 allows for selected deletion of wrappers, by introduction of names for
   115 wrapper functionals.  This implies that addbefore, addSbefore,
   116 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   117 and that adding two tactics with the same name overwrites the first
   118 one (emitting a warning).
   119   type wrapper = (int -> tactic) -> (int -> tactic)
   120   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   121   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   122   delWrapper, delSWrapper: claset *  string            -> claset
   123   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   124 
   125 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   126 semantics; addbefore now affects only the unsafe part of step_tac
   127 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   128 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   129 by Force_tac;
   130 
   131 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   132 compWrapper; added safe wrapper (and access functions for it);
   133 
   134 * HOL/split_all_tac is now much faster and fails if there is nothing
   135 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   136 and the names of the automatically generated variables have changed.
   137 split_all_tac has moved within claset() from unsafe wrappers to safe
   138 wrappers, which means that !!-bound variables are split much more
   139 aggressively, and safe_tac and clarify_tac now split such variables.
   140 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   141 Note: the same holds for record_split_tac, which does the job of
   142 split_all_tac for record fields.
   143 
   144 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   145 permanently to the default simpset using Addsplits just like
   146 Addsimps. They can be removed via Delsplits just like
   147 Delsimps. Lower-case versions are also available.
   148 
   149 * HOL/Simplifier: The rule split_if is now part of the default
   150 simpset. This means that the simplifier will eliminate all occurrences
   151 of if-then-else in the conclusion of a goal. To prevent this, you can
   152 either remove split_if completely from the default simpset by
   153 `Delsplits [split_if]' or remove it in a specific call of the
   154 simplifier using `... delsplits [split_if]'.  You can also add/delete
   155 other case splitting rules to/from the default simpset: every datatype
   156 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   157 t is the name of the datatype).
   158 
   159 * Classical reasoner / Simplifier combination: new force_tac (and
   160 derivatives Force_tac, force) combines rewriting and classical
   161 reasoning (and whatever other tools) similarly to auto_tac, but is
   162 aimed to solve the given subgoal completely.
   163 
   164 
   165 *** General ***
   166 
   167 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   168 and `goalw': the theory is no longer needed as an explicit argument -
   169 the current theory context is used; assumptions are no longer returned
   170 at the ML-level unless one of them starts with ==> or !!; it is
   171 recommended to convert to these new commands using isatool fixgoal
   172 (backup your sources first!);
   173 
   174 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   175 the current theory context, and 'theory' to lookup stored theories;
   176 
   177 * new theory section 'locale' for declaring constants, assumptions and
   178 definitions that have local scope;
   179 
   180 * new theory section 'nonterminals' for purely syntactic types;
   181 
   182 * new theory section 'setup' for generic ML setup functions
   183 (e.g. package initialization);
   184 
   185 * the distribution now includes Isabelle icons: see
   186 lib/logo/isabelle-{small,tiny}.xpm;
   187 
   188 * isatool install - install binaries with absolute references to
   189 ISABELLE_HOME/bin;
   190 
   191 * isatool logo -- create instances of the Isabelle logo (as EPS);
   192 
   193 * print mode 'emacs' reserved for Isamode;
   194 
   195 * support multiple print (ast) translations per constant name;
   196 
   197 
   198 *** HOL ***
   199 
   200 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   201 
   202 * HOL/inductive package reorganized and improved: now supports mutual
   203 definitions such as
   204 
   205   inductive EVEN ODD
   206     intrs
   207       null "0 : EVEN"
   208       oddI "n : EVEN ==> Suc n : ODD"
   209       evenI "n : ODD ==> Suc n : EVEN"
   210 
   211 new theorem list "elims" contains an elimination rule for each of the
   212 recursive sets; inductive definitions now handle disjunctive premises
   213 correctly (also ZF);
   214 
   215 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   216 "mutual_induct" no longer exists - the induction rule is always
   217 contained in "induct";
   218 
   219 
   220 * HOL/datatype package re-implemented and greatly improved: now
   221 supports mutually recursive datatypes such as
   222 
   223   datatype
   224     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   225             | SUM ('a aexp) ('a aexp)
   226             | DIFF ('a aexp) ('a aexp)
   227             | NUM 'a
   228   and
   229     'a bexp = LESS ('a aexp) ('a aexp)
   230             | AND ('a bexp) ('a bexp)
   231             | OR ('a bexp) ('a bexp)
   232 
   233 as well as indirectly recursive datatypes such as
   234 
   235   datatype
   236     ('a, 'b) term = Var 'a
   237                   | App 'b ((('a, 'b) term) list)
   238 
   239 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   240 induction on mutually / indirectly recursive datatypes.
   241 
   242 Primrec equations are now stored in theory and can be accessed via
   243 <function_name>.simps.
   244 
   245 INCOMPATIBILITIES:
   246 
   247   - Theories using datatypes must now have theory Datatype as an
   248     ancestor.
   249   - The specific <typename>.induct_tac no longer exists - use the
   250     generic induct_tac instead.
   251   - natE has been renamed to nat.exhaust - use exhaust_tac
   252     instead of res_inst_tac ... natE. Note that the variable
   253     names in nat.exhaust differ from the names in natE, this
   254     may cause some "fragile" proofs to fail.
   255   - The theorems split_<typename>_case and split_<typename>_case_asm
   256     have been renamed to <typename>.split and <typename>.split_asm.
   257   - Since default sorts of type variables are now handled correctly,
   258     some datatype definitions may have to be annotated with explicit
   259     sort constraints.
   260   - Primrec definitions no longer require function name and type
   261     of recursive argument.
   262 
   263 Consider using isatool fixdatatype to adapt your theories and proof
   264 scripts to the new package (backup your sources first!).
   265 
   266 
   267 * HOL/record package: considerably improved implementation; now
   268 includes concrete syntax for record types, terms, updates; theorems
   269 for surjective pairing and splitting !!-bound record variables; proof
   270 support is as follows:
   271 
   272   1) standard conversions (selectors or updates applied to record
   273 constructor terms) are part of the standard simpset;
   274 
   275   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   276 made part of standard simpset and claset via addIffs;
   277 
   278   3) a tactic for record field splitting (record_split_tac) is part of
   279 the standard claset (addSWrapper);
   280 
   281 To get a better idea about these rules you may retrieve them via
   282 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   283 the name of your record type.
   284 
   285 The split tactic 3) conceptually simplifies by the following rule:
   286 
   287   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   288 
   289 Thus any record variable that is bound by meta-all will automatically
   290 blow up into some record constructor term, consequently the
   291 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   292 solve record problems automatically.
   293 
   294 
   295 * reorganized the main HOL image: HOL/Integ and String loaded by
   296 default; theory Main includes everything;
   297 
   298 * automatic simplification of integer sums and comparisons, using cancellation;
   299 
   300 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   301 
   302 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   303 
   304 * many new identities for unions, intersections, set difference, etc.;
   305 
   306 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   307 called split_if, split_split, split_sum_case and split_nat_case (to go
   308 with add/delsplits);
   309 
   310 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   311 (?x::unit) = (); this is made part of the default simpset, which COULD
   312 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   313 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   314 unit_abs_eta_conv is added in order to counter the effect of
   315 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   316 %u.f();
   317 
   318 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   319 makes more sense);
   320 
   321 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   322   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   323   disjointness reasoning but breaking a few old proofs.
   324 
   325 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   326 to 'converse' from 'inverse' (for compatibility with ZF and some
   327 literature);
   328 
   329 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   330 the well-founded relation;
   331 
   332 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   333     Compl A.  The "Compl" syntax remains available as input syntax for this
   334     release ONLY.
   335 
   336 * HOL/Update: new theory of function updates:
   337     f(a:=b) == %x. if x=a then b else f x
   338 may also be iterated as in f(a:=b,c:=d,...);
   339 
   340 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   341 
   342 * HOL/List:
   343   - new function list_update written xs[i:=v] that updates the i-th
   344     list position. May also be iterated as in xs[i:=a,j:=b,...].
   345   - new function `upt' written [i..j(] which generates the list
   346     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   347     bound write [i..j], which is a shorthand for [i..j+1(].
   348   - new lexicographic orderings and corresponding wellfoundedness theorems.
   349 
   350 * HOL/Arith:
   351   - removed 'pred' (predecessor) function;
   352   - generalized some theorems about n-1;
   353   - many new laws about "div" and "mod";
   354   - new laws about greatest common divisors (see theory ex/Primes);
   355 
   356 * HOL/Relation: renamed the relational operator r^-1 "converse"
   357 instead of "inverse";
   358 
   359 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   360   of the multiset ordering;
   361 
   362 * directory HOL/Real: a construction of the reals using Dedekind cuts
   363   (not included by default);
   364 
   365 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   366 
   367 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   368   programs, i.e. different program variables may have different types.
   369 
   370 * calling (stac rew i) now fails if "rew" has no effect on the goal
   371   [previously, this check worked only if the rewrite rule was unconditional]
   372   Now rew can involve either definitions or equalities (either == or =).
   373 
   374 
   375 *** ZF ***
   376 
   377 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   378   only the theorems proved on ZF.ML;
   379 
   380 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   381   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   382   disjointness reasoning but breaking a few old proofs.
   383 
   384 * ZF/Update: new theory of function updates
   385     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   386   may also be iterated as in f(a:=b,c:=d,...);
   387 
   388 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   389 
   390 * calling (stac rew i) now fails if "rew" has no effect on the goal
   391   [previously, this check worked only if the rewrite rule was unconditional]
   392   Now rew can involve either definitions or equalities (either == or =).
   393 
   394 * case_tac provided for compatibility with HOL
   395     (like the old excluded_middle_tac, but with subgoals swapped)
   396 
   397 
   398 *** Internal programming interfaces ***
   399 
   400 * Pure: several new basic modules made available for general use, see
   401 also src/Pure/README;
   402 
   403 * improved the theory data mechanism to support encapsulation (data
   404 kind name replaced by private Object.kind, acting as authorization
   405 key); new type-safe user interface via functor TheoryDataFun; generic
   406 print_data function becomes basically useless;
   407 
   408 * removed global_names compatibility flag -- all theory declarations
   409 are qualified by default;
   410 
   411 * module Pure/Syntax now offers quote / antiquote translation
   412 functions (useful for Hoare logic etc. with implicit dependencies);
   413 see HOL/ex/Antiquote for an example use;
   414 
   415 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   416 cterm -> thm;
   417 
   418 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   419 subgoal;
   420 
   421 * Display.print_goals function moved to Locale.print_goals;
   422 
   423 * standard print function for goals supports current_goals_markers
   424 variable for marking begin of proof, end of proof, start of goal; the
   425 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   426 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   427 for example;
   428 
   429 
   430 
   431 New in Isabelle98 (January 1998)
   432 --------------------------------
   433 
   434 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   435 
   436 * changed lexical syntax of terms / types: dots made part of long
   437 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   438 
   439 * simpset (and claset) reference variable replaced by functions
   440 simpset / simpset_ref;
   441 
   442 * no longer supports theory aliases (via merge) and non-trivial
   443 implicit merge of thms' signatures;
   444 
   445 * most internal names of constants changed due to qualified names;
   446 
   447 * changed Pure/Sequence interface (see Pure/seq.ML);
   448 
   449 
   450 *** General Changes ***
   451 
   452 * hierachically structured name spaces (for consts, types, axms, thms
   453 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   454 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   455 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   456 long_names for fully qualified output names; NOTE: ML programs
   457 (special tactics, packages etc.) referring to internal names may have
   458 to be adapted to cope with fully qualified names; in case of severe
   459 backward campatibility problems try setting 'global_names' at compile
   460 time to have enrything declared within a flat name space; one may also
   461 fine tune name declarations in theories via the 'global' and 'local'
   462 section;
   463 
   464 * reimplemented the implicit simpset and claset using the new anytype
   465 data filed in signatures; references simpset:simpset ref etc. are
   466 replaced by functions simpset:unit->simpset and
   467 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   468 to patch your ML files accordingly;
   469 
   470 * HTML output now includes theory graph data for display with Java
   471 applet or isatool browser; data generated automatically via isatool
   472 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   473 
   474 * defs may now be conditional; improved rewrite_goals_tac to handle
   475 conditional equations;
   476 
   477 * defs now admits additional type arguments, using TYPE('a) syntax;
   478 
   479 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   480 creates a new theory node; implicit merge of thms' signatures is
   481 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   482 transfer:theory->thm->thm in (rare) cases;
   483 
   484 * improved handling of draft signatures / theories; draft thms (and
   485 ctyps, cterms) are automatically promoted to real ones;
   486 
   487 * slightly changed interfaces for oracles: admit many per theory, named
   488 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   489 
   490 * print_goals: optional output of const types (set show_consts and
   491 show_types);
   492 
   493 * improved output of warnings (###) and errors (***);
   494 
   495 * subgoal_tac displays a warning if the new subgoal has type variables;
   496 
   497 * removed old README and Makefiles;
   498 
   499 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   500 
   501 * removed obsolete init_pps and init_database;
   502 
   503 * deleted the obsolete tactical STATE, which was declared by
   504     fun STATE tacfun st = tacfun st st;
   505 
   506 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   507 (which abbreviates $HOME);
   508 
   509 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   510 use isatool fixseq to adapt your ML programs (this works for fully
   511 qualified references to the Sequence structure only!);
   512 
   513 * use_thy no longer requires writable current directory; it always
   514 reloads .ML *and* .thy file, if either one is out of date;
   515 
   516 
   517 *** Classical Reasoner ***
   518 
   519 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   520 tactics that use classical reasoning to simplify a subgoal without
   521 splitting it into several subgoals;
   522 
   523 * Safe_tac: like safe_tac but uses the default claset;
   524 
   525 
   526 *** Simplifier ***
   527 
   528 * added simplification meta rules:
   529     (asm_)(full_)simplify: simpset -> thm -> thm;
   530 
   531 * simplifier.ML no longer part of Pure -- has to be loaded by object
   532 logics (again);
   533 
   534 * added prems argument to simplification procedures;
   535 
   536 * HOL, FOL, ZF: added infix function `addsplits':
   537   instead of `<simpset> setloop (split_tac <thms>)'
   538   you can simply write `<simpset> addsplits <thms>'
   539 
   540 
   541 *** Syntax ***
   542 
   543 * TYPE('a) syntax for type reflection terms;
   544 
   545 * no longer handles consts with name "" -- declare as 'syntax' instead;
   546 
   547 * pretty printer: changed order of mixfix annotation preference (again!);
   548 
   549 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   550 
   551 
   552 *** HOL ***
   553 
   554 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   555   with `addloop' of the simplifier to faciliate case splitting in premises.
   556 
   557 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   558 
   559 * HOL/Auth: new protocol proofs including some for the Internet
   560   protocol TLS;
   561 
   562 * HOL/Map: new theory of `maps' a la VDM;
   563 
   564 * HOL/simplifier: simplification procedures nat_cancel_sums for
   565 cancelling out common nat summands from =, <, <= (in)equalities, or
   566 differences; simplification procedures nat_cancel_factor for
   567 cancelling common factor from =, <, <= (in)equalities over natural
   568 sums; nat_cancel contains both kinds of procedures, it is installed by
   569 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   570 
   571 * HOL/simplifier: terms of the form
   572   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   573   are rewritten to
   574   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   575   and those of the form
   576   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   577   are rewritten to
   578   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   579 
   580 * HOL/datatype
   581   Each datatype `t' now comes with a theorem `split_t_case' of the form
   582 
   583   P(t_case f1 ... fn x) =
   584      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   585         ...
   586        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   587      )
   588 
   589   and a theorem `split_t_case_asm' of the form
   590 
   591   P(t_case f1 ... fn x) =
   592     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   593         ...
   594        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   595      )
   596   which can be added to a simpset via `addsplits'. The existing theorems
   597   expand_list_case and expand_option_case have been renamed to
   598   split_list_case and split_option_case.
   599 
   600 * HOL/Arithmetic:
   601   - `pred n' is automatically converted to `n-1'.
   602     Users are strongly encouraged not to use `pred' any longer,
   603     because it will disappear altogether at some point.
   604   - Users are strongly encouraged to write "0 < n" rather than
   605     "n ~= 0". Theorems and proof tools have been modified towards this
   606     `standard'.
   607 
   608 * HOL/Lists:
   609   the function "set_of_list" has been renamed "set" (and its theorems too);
   610   the function "nth" now takes its arguments in the reverse order and
   611   has acquired the infix notation "!" as in "xs!n".
   612 
   613 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   614 
   615 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   616   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   617 
   618 * HOL/record: extensible records with schematic structural subtyping
   619 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   620 still lacks various theorems and concrete record syntax;
   621 
   622 
   623 *** HOLCF ***
   624 
   625 * removed "axioms" and "generated by" sections;
   626 
   627 * replaced "ops" section by extended "consts" section, which is capable of
   628   handling the continuous function space "->" directly;
   629 
   630 * domain package:
   631   . proves theorems immediately and stores them in the theory,
   632   . creates hierachical name space,
   633   . now uses normal mixfix annotations (instead of cinfix...),
   634   . minor changes to some names and values (for consistency),
   635   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   636   . separator between mutual domain defs: changed "," to "and",
   637   . improved handling of sort constraints;  now they have to
   638     appear on the left-hand side of the equations only;
   639 
   640 * fixed LAM <x,y,zs>.b syntax;
   641 
   642 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   643 adm (%x. P (t x)), where P is chainfinite and t continuous;
   644 
   645 
   646 *** FOL and ZF ***
   647 
   648 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
   649   with `addloop' of the simplifier to faciliate case splitting in premises.
   650 
   651 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   652 in HOL, they strip ALL and --> from proved theorems;
   653 
   654 
   655 
   656 New in Isabelle94-8 (May 1997)
   657 ------------------------------
   658 
   659 *** General Changes ***
   660 
   661 * new utilities to build / run / maintain Isabelle etc. (in parts
   662 still somewhat experimental); old Makefiles etc. still functional;
   663 
   664 * new 'Isabelle System Manual';
   665 
   666 * INSTALL text, together with ./configure and ./build scripts;
   667 
   668 * reimplemented type inference for greater efficiency, better error
   669 messages and clean internal interface;
   670 
   671 * prlim command for dealing with lots of subgoals (an easier way of
   672 setting goals_limit);
   673 
   674 
   675 *** Syntax ***
   676 
   677 * supports alternative (named) syntax tables (parser and pretty
   678 printer); internal interface is provided by add_modesyntax(_i);
   679 
   680 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   681 be used in conjunction with the Isabelle symbol font; uses the
   682 "symbols" syntax table;
   683 
   684 * added token_translation interface (may translate name tokens in
   685 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   686 the current print_mode); IMPORTANT: user print translation functions
   687 are responsible for marking newly introduced bounds
   688 (Syntax.mark_boundT);
   689 
   690 * token translations for modes "xterm" and "xterm_color" that display
   691 names in bold, underline etc. or colors (which requires a color
   692 version of xterm);
   693 
   694 * infixes may now be declared with names independent of their syntax;
   695 
   696 * added typed_print_translation (like print_translation, but may
   697 access type of constant);
   698 
   699 
   700 *** Classical Reasoner ***
   701 
   702 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   703 some limitations.  Blast_tac...
   704   + ignores addss, addbefore, addafter; this restriction is intrinsic
   705   + ignores elimination rules that don't have the correct format
   706         (the conclusion MUST be a formula variable)
   707   + ignores types, which can make HOL proofs fail
   708   + rules must not require higher-order unification, e.g. apply_type in ZF
   709     [message "Function Var's argument not a bound variable" relates to this]
   710   + its proof strategy is more general but can actually be slower
   711 
   712 * substitution with equality assumptions no longer permutes other
   713 assumptions;
   714 
   715 * minor changes in semantics of addafter (now called addaltern); renamed
   716 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   717 (and access functions for it);
   718 
   719 * improved combination of classical reasoner and simplifier:
   720   + functions for handling clasimpsets
   721   + improvement of addss: now the simplifier is called _after_ the
   722     safe steps.
   723   + safe variant of addss called addSss: uses safe simplifications
   724     _during_ the safe steps. It is more complete as it allows multiple
   725     instantiations of unknowns (e.g. with slow_tac).
   726 
   727 *** Simplifier ***
   728 
   729 * added interface for simplification procedures (functions that
   730 produce *proven* rewrite rules on the fly, depending on current
   731 redex);
   732 
   733 * ordering on terms as parameter (used for ordered rewriting);
   734 
   735 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   736 
   737 * the solver is now split into a safe and an unsafe part.
   738 This should be invisible for the normal user, except that the
   739 functions setsolver and addsolver have been renamed to setSolver and
   740 addSolver; added safe_asm_full_simp_tac;
   741 
   742 
   743 *** HOL ***
   744 
   745 * a generic induction tactic `induct_tac' which works for all datatypes and
   746 also for type `nat';
   747 
   748 * a generic case distinction tactic `exhaust_tac' which works for all
   749 datatypes and also for type `nat';
   750 
   751 * each datatype comes with a function `size';
   752 
   753 * patterns in case expressions allow tuple patterns as arguments to
   754 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   755 
   756 * primrec now also works with type nat;
   757 
   758 * recdef: a new declaration form, allows general recursive functions to be
   759 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   760 
   761 * the constant for negation has been renamed from "not" to "Not" to
   762 harmonize with FOL, ZF, LK, etc.;
   763 
   764 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   765 infinite lists;
   766 
   767 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   768 
   769 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   770 problems in commutative rings, using axiomatic type classes for + and *;
   771 
   772 * more examples in HOL/MiniML and HOL/Auth;
   773 
   774 * more default rewrite rules for quantifiers, union/intersection;
   775 
   776 * a new constant `arbitrary == @x.False';
   777 
   778 * HOLCF/IOA replaces old HOL/IOA;
   779 
   780 * HOLCF changes: derived all rules and arities
   781   + axiomatic type classes instead of classes
   782   + typedef instead of faking type definitions
   783   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   784   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   785   + eliminated the types void, one, tr
   786   + use unit lift and bool lift (with translations) instead of one and tr
   787   + eliminated blift from Lift3.thy (use Def instead of blift)
   788   all eliminated rules are derived as theorems --> no visible changes ;
   789 
   790 
   791 *** ZF ***
   792 
   793 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   794 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   795 as ZF_cs addSIs [equalityI];
   796 
   797 
   798 
   799 New in Isabelle94-7 (November 96)
   800 ---------------------------------
   801 
   802 * allowing negative levels (as offsets) in prlev and choplev;
   803 
   804 * super-linear speedup for large simplifications;
   805 
   806 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   807 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   808 FAIL); can suppress it using the command Delsimps (ex_simps @
   809 all_simps); De Morgan laws are also now included, by default;
   810 
   811 * improved printing of ==>  :  ~:
   812 
   813 * new object-logic "Sequents" adds linear logic, while replacing LK
   814 and Modal (thanks to Sara Kalvala);
   815 
   816 * HOL/Auth: correctness proofs for authentication protocols;
   817 
   818 * HOL: new auto_tac combines rewriting and classical reasoning (many
   819 examples on HOL/Auth);
   820 
   821 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   822 the rewriter and classical reasoner simultaneously;
   823 
   824 * function uresult no longer returns theorems in "standard" format;
   825 regain previous version by: val uresult = standard o uresult;
   826 
   827 
   828 
   829 New in Isabelle94-6
   830 -------------------
   831 
   832 * oracles -- these establish an interface between Isabelle and trusted
   833 external reasoners, which may deliver results as theorems;
   834 
   835 * proof objects (in particular record all uses of oracles);
   836 
   837 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   838 
   839 * "constdefs" section in theory files;
   840 
   841 * "primrec" section (HOL) no longer requires names;
   842 
   843 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   844 
   845 
   846 
   847 New in Isabelle94-5
   848 -------------------
   849 
   850 * reduced space requirements;
   851 
   852 * automatic HTML generation from theories;
   853 
   854 * theory files no longer require "..." (quotes) around most types;
   855 
   856 * new examples, including two proofs of the Church-Rosser theorem;
   857 
   858 * non-curried (1994) version of HOL is no longer distributed;
   859 
   860 
   861 
   862 New in Isabelle94-4
   863 -------------------
   864 
   865 * greatly reduced space requirements;
   866 
   867 * theory files (.thy) no longer require \...\ escapes at line breaks;
   868 
   869 * searchable theorem database (see the section "Retrieving theorems" on
   870 page 8 of the Reference Manual);
   871 
   872 * new examples, including Grabczewski's monumental case study of the
   873 Axiom of Choice;
   874 
   875 * The previous version of HOL renamed to Old_HOL;
   876 
   877 * The new version of HOL (previously called CHOL) uses a curried syntax
   878 for functions.  Application looks like f a b instead of f(a,b);
   879 
   880 * Mutually recursive inductive definitions finally work in HOL;
   881 
   882 * In ZF, pattern-matching on tuples is now available in all abstractions and
   883 translates to the operator "split";
   884 
   885 
   886 
   887 New in Isabelle94-3
   888 -------------------
   889 
   890 * new infix operator, addss, allowing the classical reasoner to
   891 perform simplification at each step of its search.  Example:
   892         fast_tac (cs addss ss)
   893 
   894 * a new logic, CHOL, the same as HOL, but with a curried syntax
   895 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
   896 look like (a,b) instead of <a,b>;
   897 
   898 * PLEASE NOTE: CHOL will eventually replace HOL!
   899 
   900 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   901 It translates to the operator "split".  A new theory of integers is available;
   902 
   903 * In ZF, integer numerals now denote two's-complement binary integers.
   904 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   905 
   906 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
   907 of the Axiom of Choice;
   908 
   909 
   910 
   911 New in Isabelle94-2
   912 -------------------
   913 
   914 * Significantly faster resolution;
   915 
   916 * the different sections in a .thy file can now be mixed and repeated
   917 freely;
   918 
   919 * Database of theorems for FOL, HOL and ZF.  New
   920 commands including qed, qed_goal and bind_thm store theorems in the database.
   921 
   922 * Simple database queries: return a named theorem (get_thm) or all theorems of
   923 a given theory (thms_of), or find out what theory a theorem was proved in
   924 (theory_of_thm);
   925 
   926 * Bugs fixed in the inductive definition and datatype packages;
   927 
   928 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   929 and HOL_dup_cs obsolete;
   930 
   931 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   932 have been removed;
   933 
   934 * Simpler definition of function space in ZF;
   935 
   936 * new results about cardinal and ordinal arithmetic in ZF;
   937 
   938 * 'subtype' facility in HOL for introducing new types as subsets of existing
   939 types;
   940 
   941 
   942 $Id$