NEWS
author paulson
Tue Jun 20 11:53:16 2000 +0200 (2000-06-20)
changeset 9092 a893887151c0
parent 9085 5ce73f3cadff
child 9185 30d46270a427
permissions -rw-r--r--
changed the Schubert Steamroller proof
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in this Isabelle version
     6 ----------------------------
     7 
     8 *** Overview of INCOMPATIBILITIES (see below for more details) ***
     9 
    10 * HOL: simplification of natural numbers is much changed; to partly
    11 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
    12 issue the following ML commands:
    13 
    14   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
    15   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
    16 
    17 * HOL: 0 is now overloaded, so the type constraint ::nat may sometimes be
    18 needed;
    19 
    20 * HOL: the constant for f``x is now "image" rather than "op ``";
    21 
    22 * HOL: the cartesian product is now "<*>" instead of "Times"; the
    23 lexicographic product is now "<*lex*>" instead of "**";
    24 
    25 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
    26 
    27 * HOL: simplification no longer dives into case-expressions
    28 
    29 * HOL: the recursion equations generated by 'recdef' are now called
    30 f.simps instead of f.rules;
    31 
    32 * HOL: theory Sexp now in HOL/Induct examples (used to be part of main
    33 HOL, but was unused); should better use HOL's datatype package anyway;
    34 
    35 * HOL/Real: "rabs" replaced by overloaded "abs" function;
    36 
    37 * HOL/ML: even fewer consts are declared as global (see theories Ord,
    38 Lfp, Gfp, WF); this only affects ML packages that refer to const names
    39 internally;
    40 
    41 * Isar: changed syntax of local blocks from {{ }} to { };
    42 
    43 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
    44 timing flag supersedes proof_timing and Toplevel.trace;
    45 
    46 * ML: PureThy.add_thms/add_axioms/add_defs return theorems as well;
    47 
    48 * LaTeX: several improvements of isabelle.sty;
    49 
    50 
    51 *** Document preparation ***
    52 
    53 * isatool mkdir provides easy setup of Isabelle session directories,
    54 including proper document sources;
    55 
    56 * generated LaTeX sources are now deleted after successful run
    57 (isatool document -c); may retain a copy somewhere else via -D option
    58 of isatool usedir;
    59 
    60 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
    61 style files, achieving self-contained LaTeX sources;
    62 
    63 * old-style theories now produce (crude) LaTeX output as well;
    64 
    65 * browser info session directories are now self-contained (may be put
    66 on WWW server seperately);
    67 
    68 
    69 *** Isar ***
    70 
    71 * Pure: local results and corresponding term bindings are now subject
    72 to Hindley-Milner polymorphism (similar to ML); this accommodates
    73 incremental type-inference nicely;
    74 
    75 * Pure: new 'obtain' language element supports generalized existence
    76 reasoning;
    77 
    78 * Pure: new calculational elements 'moreover' and 'ultimately' support
    79 plain accumulation of results, without applying any rules yet;
    80 
    81 * Pure: scalable support for case-analysis type proofs: new 'case'
    82 language element refers to local contexts symbolically, as produced by
    83 certain proof methods; internally, case names are attached to theorems
    84 as "tags";
    85 
    86 * Pure: changed syntax of local blocks from {{ }} to { };
    87 
    88 * Pure: syntax of sorts made inner, i.e. have to write "{a, b, c}"
    89 instead of {a, b, c};
    90 
    91 * Pure now provides its own version of intro/elim/dest attributes;
    92 useful for building new logics, but beware of confusion with the
    93 Provers/classical ones;
    94 
    95 * Pure: the local context of (non-atomic) goals is provided via case
    96 name 'antecedent';
    97 
    98 * Pure: removed obsolete 'transfer' attribute (transfer of thms to the
    99 current context is now done automatically);
   100 
   101 * Provers: splitter support (via 'split' attribute and 'simp' method
   102 modifier); 'simp' method: 'only:' modifier removes loopers as well
   103 (including splits);
   104 
   105 * HOL: new proof method 'cases' and improved version of 'induct' now
   106 support named cases; major packages (inductive, datatype, primrec,
   107 recdef) support case names and properly name parameters;
   108 
   109 * HOL: removed 'case_split' thm binding, should use 'cases' proof
   110 method anyway;
   111 
   112 * names of theorems etc. may be natural numbers as well;
   113 
   114 * Provers: intro/elim/dest attributes: changed ! / !! flags to ? / ??;
   115 
   116 * 'pr' command: optional goals_limit argument; no longer prints theory
   117 contexts, but only proof states;
   118 
   119 * diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   120 additional print modes to be specified; e.g. "pr(latex)" will print
   121 proof state according to the Isabelle LaTeX style;
   122 
   123 * improved support for emulating tactic scripts, including proof
   124 methods 'tactic', 'res_inst_tac' etc., 'subgoal_tac', and 'case_tac' /
   125 'induct_tac' (for HOL datatypes);
   126 
   127 * simplified (more robust) goal selection of proof methods: 1st goal,
   128 all goals, or explicit goal specifier (tactic emulation); thus 'proof
   129 method scripts' have to be in depth-first order;
   130 
   131 * tuned 'let' syntax: replace 'as' keyword by 'and';
   132 
   133 * theory command 'hide' removes declarations from class/type/const
   134 name spaces;
   135 
   136 
   137 *** HOL ***
   138 
   139 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog
   140 
   141 * HOL/Algebra: new theory of rings and univariate polynomials, by
   142 Clemens Ballarin;
   143 
   144 * HOL/record: fixed select-update simplification procedure to handle
   145 extended records as well; admit "r" as field name;
   146 
   147 * HOL/ex: new theory Factorization proving the Fundamental Theorem of
   148 Arithmetic, by Thomas M Rasmussen;
   149 
   150 * HOL/ex/Multiquote: multiple nested quotations and anti-quotations --
   151 basically a generalized version of de-Bruijn representation; very
   152 useful in avoiding lifting all operations;
   153 
   154 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   155 
   156 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   157 other numeric types and also as the identity of groups, rings, etc.;
   158 
   159 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   160 Types nat and int belong to this axclass;
   161 
   162 * greatly improved simplification involving numerals of type nat, int, real:
   163    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   164    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   165   two terms #m*u and #n*u are replaced by #(m+n)*u
   166     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   167   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   168     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   169 
   170 * HOL: new version of "case_tac" subsumes both boolean case split and
   171 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   172 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   173 
   174 * HOL: simplification no longer dives into case-expressions: only the
   175 selector expression is simplified, but not the remaining arms. To
   176 enable full simplification of case-expressions for datatype t, you
   177 need to remove t.weak_case_cong from the simpset, either permanently
   178 (Delcongs[thm"t.weak_case_cong"];) or locally (delcongs [...]).
   179 
   180 * HOL/recdef: the recursion equations generated by 'recdef' for
   181 function 'f' are now called f.simps instead of f.rules; if all
   182 termination conditions are proved automatically, these simplification
   183 rules are added to the simpset, as in primrec; rules may be named
   184 individually as well, resulting in a separate list of theorems for
   185 each equation;
   186 
   187 * HOL: new (overloaded) notation for the set of elements below/above some
   188 element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   189 
   190 * HOL: theorems impI, allI, ballI bound as "strip";
   191 
   192 * theory Sexp now in HOL/Induct examples (used to be part of main HOL,
   193 but was unused);
   194 
   195 * fewer consts declared as global (e.g. have to refer to "Lfp.lfp"
   196 instead of "lfp" internally; affects ML packages only);
   197 
   198 
   199 *** General ***
   200 
   201 * improved name spaces: ambiguous output is qualified; support for
   202 hiding of names;
   203 
   204 * compression of ML heaps images may now be controlled via -c option
   205 of isabelle and isatool usedir (currently only observed by Poly/ML);
   206 
   207 * provide TAGS file for Isabelle sources;
   208 
   209 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   210 timing flag supersedes proof_timing and Toplevel.trace;
   211 
   212 * ML: new combinators |>> and |>>> for incremental transformations
   213 with secondary results (e.g. certain theory extensions):
   214 
   215 
   216 
   217 New in Isabelle99 (October 1999)
   218 --------------------------------
   219 
   220 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   221 
   222 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   223 are no longer simplified.  (This allows the simplifier to unfold recursive
   224 functional programs.)  To restore the old behaviour, declare
   225 
   226     Delcongs [if_weak_cong];
   227 
   228 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   229 complement;
   230 
   231 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   232 
   233 * HOL/datatype: mutual_induct_tac no longer exists --
   234   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   235 
   236 * HOL/typedef: fixed type inference for representing set; type
   237 arguments now have to occur explicitly on the rhs as type constraints;
   238 
   239 * ZF: The con_defs part of an inductive definition may no longer refer
   240 to constants declared in the same theory;
   241 
   242 * HOL, ZF: the function mk_cases, generated by the inductive
   243 definition package, has lost an argument.  To simplify its result, it
   244 uses the default simpset instead of a supplied list of theorems.
   245 
   246 * HOL/List: the constructors of type list are now Nil and Cons;
   247 
   248 * Simplifier: the type of the infix ML functions
   249         setSSolver addSSolver setSolver addSolver
   250 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   251 for packaging solvers. A solver is created via
   252         mk_solver: string -> (thm list -> int -> tactic) -> solver
   253 where the string argument is only a comment.
   254 
   255 
   256 *** Proof tools ***
   257 
   258 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   259 decision procedure for linear arithmetic. Currently it is used for
   260 types `nat', `int', and `real' in HOL (see below); it can, should and
   261 will be instantiated for other types and logics as well.
   262 
   263 * The simplifier now accepts rewrite rules with flexible heads, eg
   264      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   265   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   266   matching.
   267 
   268 
   269 *** General ***
   270 
   271 * New Isabelle/Isar subsystem provides an alternative to traditional
   272 tactical theorem proving; together with the ProofGeneral/isar user
   273 interface it offers an interactive environment for developing human
   274 readable proof documents (Isar == Intelligible semi-automated
   275 reasoning); for further information see isatool doc isar-ref,
   276 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   277 
   278 * improved presentation of theories: better HTML markup (including
   279 colors), graph views in several sizes; isatool usedir now provides a
   280 proper interface for user theories (via -P option); actual document
   281 preparation based on (PDF)LaTeX is available as well (for new-style
   282 theories only); see isatool doc system for more information;
   283 
   284 * native support for Proof General, both for classic Isabelle and
   285 Isabelle/Isar;
   286 
   287 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   288 using the graph browser tool;
   289 
   290 * Isabelle manuals now also available as PDF;
   291 
   292 * theory loader rewritten from scratch (may not be fully
   293 bug-compatible); old loadpath variable has been replaced by show_path,
   294 add_path, del_path, reset_path functions; new operations such as
   295 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   296 isatool doc ref);
   297 
   298 * improved isatool install: option -k creates KDE application icon,
   299 option -p DIR installs standalone binaries;
   300 
   301 * added ML_PLATFORM setting (useful for cross-platform installations);
   302 more robust handling of platform specific ML images for SML/NJ;
   303 
   304 * the settings environment is now statically scoped, i.e. it is never
   305 created again in sub-processes invoked from isabelle, isatool, or
   306 Isabelle;
   307 
   308 * path element specification '~~' refers to '$ISABELLE_HOME';
   309 
   310 * in locales, the "assumes" and "defines" parts may be omitted if
   311 empty;
   312 
   313 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   314 long arrows);
   315 
   316 * new print_mode "HTML";
   317 
   318 * new flag show_tags controls display of tags of theorems (which are
   319 basically just comments that may be attached by some tools);
   320 
   321 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   322 mode and goal output format:
   323 
   324 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   325 244c244
   326 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   327 ---
   328 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   329 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   330 181c181
   331 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   332 ---
   333 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   334 
   335 * function bind_thms stores lists of theorems (cf. bind_thm);
   336 
   337 * new shorthand tactics ftac, eatac, datac, fatac;
   338 
   339 * qed (and friends) now accept "" as result name; in that case the
   340 theorem is not stored, but proper checks and presentation of the
   341 result still apply;
   342 
   343 * theorem database now also indexes constants "Trueprop", "all",
   344 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   345 
   346 
   347 *** HOL ***
   348 
   349 ** HOL arithmetic **
   350 
   351 * There are now decision procedures for linear arithmetic over nat and
   352 int:
   353 
   354 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   355 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   356 are treated as atomic; subformulae not involving type `nat' or `int'
   357 are ignored; quantified subformulae are ignored unless they are
   358 positive universal or negative existential. The tactic has to be
   359 invoked by hand and can be a little bit slow. In particular, the
   360 running time is exponential in the number of occurrences of `min' and
   361 `max', and `-' on `nat'.
   362 
   363 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   364 (negated) (in)equalities among the premises and the conclusion into
   365 account (i.e. no compound formulae) and does not know about `min' and
   366 `max', and `-' on `nat'. It is fast and is used automatically by the
   367 simplifier.
   368 
   369 NB: At the moment, these decision procedures do not cope with mixed
   370 nat/int formulae where the two parts interact, such as `m < n ==>
   371 int(m) < int(n)'.
   372 
   373 * HOL/Numeral provides a generic theory of numerals (encoded
   374 efficiently as bit strings); setup for types nat/int/real is in place;
   375 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   376 int, existing theories and proof scripts may require a few additional
   377 type constraints;
   378 
   379 * integer division and remainder can now be performed on constant
   380 arguments;
   381 
   382 * many properties of integer multiplication, division and remainder
   383 are now available;
   384 
   385 * An interface to the Stanford Validity Checker (SVC) is available through the
   386 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   387 are proved automatically.  SVC must be installed separately, and its results
   388 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   389 invocation of the underlying oracle).  For SVC see
   390   http://verify.stanford.edu/SVC
   391 
   392 * IsaMakefile: the HOL-Real target now builds an actual image;
   393 
   394 
   395 ** HOL misc **
   396 
   397 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   398 (in Isabelle/Isar) -- by Gertrud Bauer;
   399 
   400 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   401 analysis for assembly languages with subtypes;
   402 
   403 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   404 -- avoids syntactic ambiguities and treats state, transition, and
   405 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   406 changed syntax and (many) tactics;
   407 
   408 * HOL/inductive: Now also handles more general introduction rules such
   409   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   410   theorems are now maintained within the theory (maintained via the
   411   "mono" attribute);
   412 
   413 * HOL/datatype: Now also handles arbitrarily branching datatypes
   414   (using function types) such as
   415 
   416   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   417 
   418 * HOL/record: record_simproc (part of the default simpset) takes care
   419 of selectors applied to updated records; record_split_tac is no longer
   420 part of the default claset; update_defs may now be removed from the
   421 simpset in many cases; COMPATIBILITY: old behavior achieved by
   422 
   423   claset_ref () := claset() addSWrapper record_split_wrapper;
   424   Delsimprocs [record_simproc]
   425 
   426 * HOL/typedef: fixed type inference for representing set; type
   427 arguments now have to occur explicitly on the rhs as type constraints;
   428 
   429 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   430 names rather than an ML expression;
   431 
   432 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   433 supplied later.  Program schemes can be defined, such as
   434     "While B C s = (if B s then While B C (C s) else s)"
   435 where the well-founded relation can be chosen after B and C have been given.
   436 
   437 * HOL/List: the constructors of type list are now Nil and Cons;
   438 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   439 course, ML tools referring to List.list.op # etc. have to be adapted;
   440 
   441 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   442 disabled by default; run isabelle with option -m HOL to get back to
   443 the original Gordon/HOL-style output;
   444 
   445 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   446 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   447 
   448 * HOL basic syntax simplified (more orthogonal): all variants of
   449 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   450 Eps operator is provided as well: "SOME x. P[x]";
   451 
   452 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   453 
   454 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   455 thus available for user theories;
   456 
   457 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   458 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   459 time;
   460 
   461 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   462 several times and then mp;
   463 
   464 
   465 *** LK ***
   466 
   467 * the notation <<...>> is now available as a notation for sequences of
   468 formulas;
   469 
   470 * the simplifier is now installed
   471 
   472 * the axiom system has been generalized (thanks to Soren Heilmann)
   473 
   474 * the classical reasoner now has a default rule database
   475 
   476 
   477 *** ZF ***
   478 
   479 * new primrec section allows primitive recursive functions to be given
   480 directly (as in HOL) over datatypes and the natural numbers;
   481 
   482 * new tactics induct_tac and exhaust_tac for induction (or case
   483 analysis) over datatypes and the natural numbers;
   484 
   485 * the datatype declaration of type T now defines the recursor T_rec;
   486 
   487 * simplification automatically does freeness reasoning for datatype
   488 constructors;
   489 
   490 * automatic type-inference, with AddTCs command to insert new
   491 type-checking rules;
   492 
   493 * datatype introduction rules are now added as Safe Introduction rules
   494 to the claset;
   495 
   496 * the syntax "if P then x else y" is now available in addition to
   497 if(P,x,y);
   498 
   499 
   500 *** Internal programming interfaces ***
   501 
   502 * tuned simplifier trace output; new flag debug_simp;
   503 
   504 * structures Vartab / Termtab (instances of TableFun) offer efficient
   505 tables indexed by indexname_ord / term_ord (compatible with aconv);
   506 
   507 * AxClass.axclass_tac lost the theory argument;
   508 
   509 * tuned current_goals_markers semantics: begin / end goal avoids
   510 printing empty lines;
   511 
   512 * removed prs and prs_fn hook, which was broken because it did not
   513 include \n in its semantics, forcing writeln to add one
   514 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   515 string -> unit if you really want to output text without newline;
   516 
   517 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   518 plain output, interface builders may have to enable 'isabelle_font'
   519 mode to get Isabelle font glyphs as before;
   520 
   521 * refined token_translation interface; INCOMPATIBILITY: output length
   522 now of type real instead of int;
   523 
   524 * theory loader actions may be traced via new ThyInfo.add_hook
   525 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   526 your own database of information attached to *whole* theories -- as
   527 opposed to intra-theory data slots offered via TheoryDataFun;
   528 
   529 * proper handling of dangling sort hypotheses (at last!);
   530 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   531 extra sort hypotheses that can be witnessed from the type signature;
   532 the force_strip_shyps flag is gone, any remaining shyps are simply
   533 left in the theorem (with a warning issued by strip_shyps_warning);
   534 
   535 
   536 
   537 New in Isabelle98-1 (October 1998)
   538 ----------------------------------
   539 
   540 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   541 
   542 * several changes of automated proof tools;
   543 
   544 * HOL: major changes to the inductive and datatype packages, including
   545 some minor incompatibilities of theory syntax;
   546 
   547 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   548 called `inj_on';
   549 
   550 * HOL: removed duplicate thms in Arith:
   551   less_imp_add_less  should be replaced by  trans_less_add1
   552   le_imp_add_le      should be replaced by  trans_le_add1
   553 
   554 * HOL: unary minus is now overloaded (new type constraints may be
   555 required);
   556 
   557 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   558 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   559 now taken as an integer constant.
   560 
   561 * Pure: ML function 'theory_of' renamed to 'theory';
   562 
   563 
   564 *** Proof tools ***
   565 
   566 * Simplifier:
   567   1. Asm_full_simp_tac is now more aggressive.
   568      1. It will sometimes reorient premises if that increases their power to
   569         simplify.
   570      2. It does no longer proceed strictly from left to right but may also
   571         rotate premises to achieve further simplification.
   572      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   573      old Asm_full_simp_tac in that it does not rotate premises.
   574   2. The simplifier now knows a little bit about nat-arithmetic.
   575 
   576 * Classical reasoner: wrapper mechanism for the classical reasoner now
   577 allows for selected deletion of wrappers, by introduction of names for
   578 wrapper functionals.  This implies that addbefore, addSbefore,
   579 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   580 and that adding two tactics with the same name overwrites the first
   581 one (emitting a warning).
   582   type wrapper = (int -> tactic) -> (int -> tactic)
   583   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   584   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   585   delWrapper, delSWrapper: claset *  string            -> claset
   586   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   587 
   588 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   589 semantics; addbefore now affects only the unsafe part of step_tac
   590 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   591 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   592 by Force_tac;
   593 
   594 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   595 compWrapper; added safe wrapper (and access functions for it);
   596 
   597 * HOL/split_all_tac is now much faster and fails if there is nothing
   598 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   599 and the names of the automatically generated variables have changed.
   600 split_all_tac has moved within claset() from unsafe wrappers to safe
   601 wrappers, which means that !!-bound variables are split much more
   602 aggressively, and safe_tac and clarify_tac now split such variables.
   603 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   604 Note: the same holds for record_split_tac, which does the job of
   605 split_all_tac for record fields.
   606 
   607 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   608 permanently to the default simpset using Addsplits just like
   609 Addsimps. They can be removed via Delsplits just like
   610 Delsimps. Lower-case versions are also available.
   611 
   612 * HOL/Simplifier: The rule split_if is now part of the default
   613 simpset. This means that the simplifier will eliminate all occurrences
   614 of if-then-else in the conclusion of a goal. To prevent this, you can
   615 either remove split_if completely from the default simpset by
   616 `Delsplits [split_if]' or remove it in a specific call of the
   617 simplifier using `... delsplits [split_if]'.  You can also add/delete
   618 other case splitting rules to/from the default simpset: every datatype
   619 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   620 t is the name of the datatype).
   621 
   622 * Classical reasoner / Simplifier combination: new force_tac (and
   623 derivatives Force_tac, force) combines rewriting and classical
   624 reasoning (and whatever other tools) similarly to auto_tac, but is
   625 aimed to solve the given subgoal completely.
   626 
   627 
   628 *** General ***
   629 
   630 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   631 and `goalw': the theory is no longer needed as an explicit argument -
   632 the current theory context is used; assumptions are no longer returned
   633 at the ML-level unless one of them starts with ==> or !!; it is
   634 recommended to convert to these new commands using isatool fixgoal
   635 (backup your sources first!);
   636 
   637 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   638 the current theory context, and 'theory' to lookup stored theories;
   639 
   640 * new theory section 'locale' for declaring constants, assumptions and
   641 definitions that have local scope;
   642 
   643 * new theory section 'nonterminals' for purely syntactic types;
   644 
   645 * new theory section 'setup' for generic ML setup functions
   646 (e.g. package initialization);
   647 
   648 * the distribution now includes Isabelle icons: see
   649 lib/logo/isabelle-{small,tiny}.xpm;
   650 
   651 * isatool install - install binaries with absolute references to
   652 ISABELLE_HOME/bin;
   653 
   654 * isatool logo -- create instances of the Isabelle logo (as EPS);
   655 
   656 * print mode 'emacs' reserved for Isamode;
   657 
   658 * support multiple print (ast) translations per constant name;
   659 
   660 * theorems involving oracles are now printed with a suffixed [!];
   661 
   662 
   663 *** HOL ***
   664 
   665 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   666 
   667 * HOL/inductive package reorganized and improved: now supports mutual
   668 definitions such as
   669 
   670   inductive EVEN ODD
   671     intrs
   672       null "0 : EVEN"
   673       oddI "n : EVEN ==> Suc n : ODD"
   674       evenI "n : ODD ==> Suc n : EVEN"
   675 
   676 new theorem list "elims" contains an elimination rule for each of the
   677 recursive sets; inductive definitions now handle disjunctive premises
   678 correctly (also ZF);
   679 
   680 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   681 "mutual_induct" no longer exists - the induction rule is always
   682 contained in "induct";
   683 
   684 
   685 * HOL/datatype package re-implemented and greatly improved: now
   686 supports mutually recursive datatypes such as
   687 
   688   datatype
   689     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   690             | SUM ('a aexp) ('a aexp)
   691             | DIFF ('a aexp) ('a aexp)
   692             | NUM 'a
   693   and
   694     'a bexp = LESS ('a aexp) ('a aexp)
   695             | AND ('a bexp) ('a bexp)
   696             | OR ('a bexp) ('a bexp)
   697 
   698 as well as indirectly recursive datatypes such as
   699 
   700   datatype
   701     ('a, 'b) term = Var 'a
   702                   | App 'b ((('a, 'b) term) list)
   703 
   704 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   705 induction on mutually / indirectly recursive datatypes.
   706 
   707 Primrec equations are now stored in theory and can be accessed via
   708 <function_name>.simps.
   709 
   710 INCOMPATIBILITIES:
   711 
   712   - Theories using datatypes must now have theory Datatype as an
   713     ancestor.
   714   - The specific <typename>.induct_tac no longer exists - use the
   715     generic induct_tac instead.
   716   - natE has been renamed to nat.exhaust - use exhaust_tac
   717     instead of res_inst_tac ... natE. Note that the variable
   718     names in nat.exhaust differ from the names in natE, this
   719     may cause some "fragile" proofs to fail.
   720   - The theorems split_<typename>_case and split_<typename>_case_asm
   721     have been renamed to <typename>.split and <typename>.split_asm.
   722   - Since default sorts of type variables are now handled correctly,
   723     some datatype definitions may have to be annotated with explicit
   724     sort constraints.
   725   - Primrec definitions no longer require function name and type
   726     of recursive argument.
   727 
   728 Consider using isatool fixdatatype to adapt your theories and proof
   729 scripts to the new package (backup your sources first!).
   730 
   731 
   732 * HOL/record package: considerably improved implementation; now
   733 includes concrete syntax for record types, terms, updates; theorems
   734 for surjective pairing and splitting !!-bound record variables; proof
   735 support is as follows:
   736 
   737   1) standard conversions (selectors or updates applied to record
   738 constructor terms) are part of the standard simpset;
   739 
   740   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   741 made part of standard simpset and claset via addIffs;
   742 
   743   3) a tactic for record field splitting (record_split_tac) is part of
   744 the standard claset (addSWrapper);
   745 
   746 To get a better idea about these rules you may retrieve them via
   747 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   748 the name of your record type.
   749 
   750 The split tactic 3) conceptually simplifies by the following rule:
   751 
   752   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   753 
   754 Thus any record variable that is bound by meta-all will automatically
   755 blow up into some record constructor term, consequently the
   756 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   757 solve record problems automatically.
   758 
   759 
   760 * reorganized the main HOL image: HOL/Integ and String loaded by
   761 default; theory Main includes everything;
   762 
   763 * automatic simplification of integer sums and comparisons, using cancellation;
   764 
   765 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   766 
   767 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   768 
   769 * many new identities for unions, intersections, set difference, etc.;
   770 
   771 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   772 called split_if, split_split, split_sum_case and split_nat_case (to go
   773 with add/delsplits);
   774 
   775 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   776 (?x::unit) = (); this is made part of the default simpset, which COULD
   777 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   778 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   779 unit_abs_eta_conv is added in order to counter the effect of
   780 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   781 %u.f();
   782 
   783 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   784 makes more sense);
   785 
   786 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   787   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   788   disjointness reasoning but breaking a few old proofs.
   789 
   790 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   791 to 'converse' from 'inverse' (for compatibility with ZF and some
   792 literature);
   793 
   794 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   795 the well-founded relation;
   796 
   797 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   798     Compl A.  The "Compl" syntax remains available as input syntax for this
   799     release ONLY.
   800 
   801 * HOL/Update: new theory of function updates:
   802     f(a:=b) == %x. if x=a then b else f x
   803 may also be iterated as in f(a:=b,c:=d,...);
   804 
   805 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   806 
   807 * HOL/List:
   808   - new function list_update written xs[i:=v] that updates the i-th
   809     list position. May also be iterated as in xs[i:=a,j:=b,...].
   810   - new function `upt' written [i..j(] which generates the list
   811     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   812     bound write [i..j], which is a shorthand for [i..j+1(].
   813   - new lexicographic orderings and corresponding wellfoundedness theorems.
   814 
   815 * HOL/Arith:
   816   - removed 'pred' (predecessor) function;
   817   - generalized some theorems about n-1;
   818   - many new laws about "div" and "mod";
   819   - new laws about greatest common divisors (see theory ex/Primes);
   820 
   821 * HOL/Relation: renamed the relational operator r^-1 "converse"
   822 instead of "inverse";
   823 
   824 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   825   of the multiset ordering;
   826 
   827 * directory HOL/Real: a construction of the reals using Dedekind cuts
   828   (not included by default);
   829 
   830 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   831 
   832 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   833   programs, i.e. different program variables may have different types.
   834 
   835 * calling (stac rew i) now fails if "rew" has no effect on the goal
   836   [previously, this check worked only if the rewrite rule was unconditional]
   837   Now rew can involve either definitions or equalities (either == or =).
   838 
   839 
   840 *** ZF ***
   841 
   842 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   843   only the theorems proved on ZF.ML;
   844 
   845 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   846   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   847   disjointness reasoning but breaking a few old proofs.
   848 
   849 * ZF/Update: new theory of function updates
   850     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   851   may also be iterated as in f(a:=b,c:=d,...);
   852 
   853 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   854 
   855 * calling (stac rew i) now fails if "rew" has no effect on the goal
   856   [previously, this check worked only if the rewrite rule was unconditional]
   857   Now rew can involve either definitions or equalities (either == or =).
   858 
   859 * case_tac provided for compatibility with HOL
   860     (like the old excluded_middle_tac, but with subgoals swapped)
   861 
   862 
   863 *** Internal programming interfaces ***
   864 
   865 * Pure: several new basic modules made available for general use, see
   866 also src/Pure/README;
   867 
   868 * improved the theory data mechanism to support encapsulation (data
   869 kind name replaced by private Object.kind, acting as authorization
   870 key); new type-safe user interface via functor TheoryDataFun; generic
   871 print_data function becomes basically useless;
   872 
   873 * removed global_names compatibility flag -- all theory declarations
   874 are qualified by default;
   875 
   876 * module Pure/Syntax now offers quote / antiquote translation
   877 functions (useful for Hoare logic etc. with implicit dependencies);
   878 see HOL/ex/Antiquote for an example use;
   879 
   880 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   881 cterm -> thm;
   882 
   883 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   884 subgoal;
   885 
   886 * Display.print_goals function moved to Locale.print_goals;
   887 
   888 * standard print function for goals supports current_goals_markers
   889 variable for marking begin of proof, end of proof, start of goal; the
   890 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   891 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   892 for example;
   893 
   894 
   895 
   896 New in Isabelle98 (January 1998)
   897 --------------------------------
   898 
   899 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   900 
   901 * changed lexical syntax of terms / types: dots made part of long
   902 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   903 
   904 * simpset (and claset) reference variable replaced by functions
   905 simpset / simpset_ref;
   906 
   907 * no longer supports theory aliases (via merge) and non-trivial
   908 implicit merge of thms' signatures;
   909 
   910 * most internal names of constants changed due to qualified names;
   911 
   912 * changed Pure/Sequence interface (see Pure/seq.ML);
   913 
   914 
   915 *** General Changes ***
   916 
   917 * hierachically structured name spaces (for consts, types, axms, thms
   918 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   919 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   920 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   921 long_names for fully qualified output names; NOTE: ML programs
   922 (special tactics, packages etc.) referring to internal names may have
   923 to be adapted to cope with fully qualified names; in case of severe
   924 backward campatibility problems try setting 'global_names' at compile
   925 time to have enrything declared within a flat name space; one may also
   926 fine tune name declarations in theories via the 'global' and 'local'
   927 section;
   928 
   929 * reimplemented the implicit simpset and claset using the new anytype
   930 data filed in signatures; references simpset:simpset ref etc. are
   931 replaced by functions simpset:unit->simpset and
   932 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   933 to patch your ML files accordingly;
   934 
   935 * HTML output now includes theory graph data for display with Java
   936 applet or isatool browser; data generated automatically via isatool
   937 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   938 
   939 * defs may now be conditional; improved rewrite_goals_tac to handle
   940 conditional equations;
   941 
   942 * defs now admits additional type arguments, using TYPE('a) syntax;
   943 
   944 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   945 creates a new theory node; implicit merge of thms' signatures is
   946 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   947 transfer:theory->thm->thm in (rare) cases;
   948 
   949 * improved handling of draft signatures / theories; draft thms (and
   950 ctyps, cterms) are automatically promoted to real ones;
   951 
   952 * slightly changed interfaces for oracles: admit many per theory, named
   953 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   954 
   955 * print_goals: optional output of const types (set show_consts and
   956 show_types);
   957 
   958 * improved output of warnings (###) and errors (***);
   959 
   960 * subgoal_tac displays a warning if the new subgoal has type variables;
   961 
   962 * removed old README and Makefiles;
   963 
   964 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   965 
   966 * removed obsolete init_pps and init_database;
   967 
   968 * deleted the obsolete tactical STATE, which was declared by
   969     fun STATE tacfun st = tacfun st st;
   970 
   971 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   972 (which abbreviates $HOME);
   973 
   974 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   975 use isatool fixseq to adapt your ML programs (this works for fully
   976 qualified references to the Sequence structure only!);
   977 
   978 * use_thy no longer requires writable current directory; it always
   979 reloads .ML *and* .thy file, if either one is out of date;
   980 
   981 
   982 *** Classical Reasoner ***
   983 
   984 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   985 tactics that use classical reasoning to simplify a subgoal without
   986 splitting it into several subgoals;
   987 
   988 * Safe_tac: like safe_tac but uses the default claset;
   989 
   990 
   991 *** Simplifier ***
   992 
   993 * added simplification meta rules:
   994     (asm_)(full_)simplify: simpset -> thm -> thm;
   995 
   996 * simplifier.ML no longer part of Pure -- has to be loaded by object
   997 logics (again);
   998 
   999 * added prems argument to simplification procedures;
  1000 
  1001 * HOL, FOL, ZF: added infix function `addsplits':
  1002   instead of `<simpset> setloop (split_tac <thms>)'
  1003   you can simply write `<simpset> addsplits <thms>'
  1004 
  1005 
  1006 *** Syntax ***
  1007 
  1008 * TYPE('a) syntax for type reflection terms;
  1009 
  1010 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1011 
  1012 * pretty printer: changed order of mixfix annotation preference (again!);
  1013 
  1014 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1015 
  1016 
  1017 *** HOL ***
  1018 
  1019 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1020   with `addloop' of the simplifier to faciliate case splitting in premises.
  1021 
  1022 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1023 
  1024 * HOL/Auth: new protocol proofs including some for the Internet
  1025   protocol TLS;
  1026 
  1027 * HOL/Map: new theory of `maps' a la VDM;
  1028 
  1029 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1030 cancelling out common nat summands from =, <, <= (in)equalities, or
  1031 differences; simplification procedures nat_cancel_factor for
  1032 cancelling common factor from =, <, <= (in)equalities over natural
  1033 sums; nat_cancel contains both kinds of procedures, it is installed by
  1034 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1035 
  1036 * HOL/simplifier: terms of the form
  1037   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1038   are rewritten to
  1039   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1040   and those of the form
  1041   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1042   are rewritten to
  1043   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1044 
  1045 * HOL/datatype
  1046   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1047 
  1048   P(t_case f1 ... fn x) =
  1049      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1050         ...
  1051        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1052      )
  1053 
  1054   and a theorem `split_t_case_asm' of the form
  1055 
  1056   P(t_case f1 ... fn x) =
  1057     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1058         ...
  1059        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1060      )
  1061   which can be added to a simpset via `addsplits'. The existing theorems
  1062   expand_list_case and expand_option_case have been renamed to
  1063   split_list_case and split_option_case.
  1064 
  1065 * HOL/Arithmetic:
  1066   - `pred n' is automatically converted to `n-1'.
  1067     Users are strongly encouraged not to use `pred' any longer,
  1068     because it will disappear altogether at some point.
  1069   - Users are strongly encouraged to write "0 < n" rather than
  1070     "n ~= 0". Theorems and proof tools have been modified towards this
  1071     `standard'.
  1072 
  1073 * HOL/Lists:
  1074   the function "set_of_list" has been renamed "set" (and its theorems too);
  1075   the function "nth" now takes its arguments in the reverse order and
  1076   has acquired the infix notation "!" as in "xs!n".
  1077 
  1078 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1079 
  1080 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1081   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1082 
  1083 * HOL/record: extensible records with schematic structural subtyping
  1084 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1085 still lacks various theorems and concrete record syntax;
  1086 
  1087 
  1088 *** HOLCF ***
  1089 
  1090 * removed "axioms" and "generated by" sections;
  1091 
  1092 * replaced "ops" section by extended "consts" section, which is capable of
  1093   handling the continuous function space "->" directly;
  1094 
  1095 * domain package:
  1096   . proves theorems immediately and stores them in the theory,
  1097   . creates hierachical name space,
  1098   . now uses normal mixfix annotations (instead of cinfix...),
  1099   . minor changes to some names and values (for consistency),
  1100   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1101   . separator between mutual domain defs: changed "," to "and",
  1102   . improved handling of sort constraints;  now they have to
  1103     appear on the left-hand side of the equations only;
  1104 
  1105 * fixed LAM <x,y,zs>.b syntax;
  1106 
  1107 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1108 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1109 
  1110 
  1111 *** FOL and ZF ***
  1112 
  1113 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1114   with `addloop' of the simplifier to faciliate case splitting in premises.
  1115 
  1116 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1117 in HOL, they strip ALL and --> from proved theorems;
  1118 
  1119 
  1120 
  1121 New in Isabelle94-8 (May 1997)
  1122 ------------------------------
  1123 
  1124 *** General Changes ***
  1125 
  1126 * new utilities to build / run / maintain Isabelle etc. (in parts
  1127 still somewhat experimental); old Makefiles etc. still functional;
  1128 
  1129 * new 'Isabelle System Manual';
  1130 
  1131 * INSTALL text, together with ./configure and ./build scripts;
  1132 
  1133 * reimplemented type inference for greater efficiency, better error
  1134 messages and clean internal interface;
  1135 
  1136 * prlim command for dealing with lots of subgoals (an easier way of
  1137 setting goals_limit);
  1138 
  1139 
  1140 *** Syntax ***
  1141 
  1142 * supports alternative (named) syntax tables (parser and pretty
  1143 printer); internal interface is provided by add_modesyntax(_i);
  1144 
  1145 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1146 be used in conjunction with the Isabelle symbol font; uses the
  1147 "symbols" syntax table;
  1148 
  1149 * added token_translation interface (may translate name tokens in
  1150 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1151 the current print_mode); IMPORTANT: user print translation functions
  1152 are responsible for marking newly introduced bounds
  1153 (Syntax.mark_boundT);
  1154 
  1155 * token translations for modes "xterm" and "xterm_color" that display
  1156 names in bold, underline etc. or colors (which requires a color
  1157 version of xterm);
  1158 
  1159 * infixes may now be declared with names independent of their syntax;
  1160 
  1161 * added typed_print_translation (like print_translation, but may
  1162 access type of constant);
  1163 
  1164 
  1165 *** Classical Reasoner ***
  1166 
  1167 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1168 some limitations.  Blast_tac...
  1169   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1170   + ignores elimination rules that don't have the correct format
  1171         (the conclusion MUST be a formula variable)
  1172   + ignores types, which can make HOL proofs fail
  1173   + rules must not require higher-order unification, e.g. apply_type in ZF
  1174     [message "Function Var's argument not a bound variable" relates to this]
  1175   + its proof strategy is more general but can actually be slower
  1176 
  1177 * substitution with equality assumptions no longer permutes other
  1178 assumptions;
  1179 
  1180 * minor changes in semantics of addafter (now called addaltern); renamed
  1181 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1182 (and access functions for it);
  1183 
  1184 * improved combination of classical reasoner and simplifier:
  1185   + functions for handling clasimpsets
  1186   + improvement of addss: now the simplifier is called _after_ the
  1187     safe steps.
  1188   + safe variant of addss called addSss: uses safe simplifications
  1189     _during_ the safe steps. It is more complete as it allows multiple
  1190     instantiations of unknowns (e.g. with slow_tac).
  1191 
  1192 *** Simplifier ***
  1193 
  1194 * added interface for simplification procedures (functions that
  1195 produce *proven* rewrite rules on the fly, depending on current
  1196 redex);
  1197 
  1198 * ordering on terms as parameter (used for ordered rewriting);
  1199 
  1200 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1201 
  1202 * the solver is now split into a safe and an unsafe part.
  1203 This should be invisible for the normal user, except that the
  1204 functions setsolver and addsolver have been renamed to setSolver and
  1205 addSolver; added safe_asm_full_simp_tac;
  1206 
  1207 
  1208 *** HOL ***
  1209 
  1210 * a generic induction tactic `induct_tac' which works for all datatypes and
  1211 also for type `nat';
  1212 
  1213 * a generic case distinction tactic `exhaust_tac' which works for all
  1214 datatypes and also for type `nat';
  1215 
  1216 * each datatype comes with a function `size';
  1217 
  1218 * patterns in case expressions allow tuple patterns as arguments to
  1219 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1220 
  1221 * primrec now also works with type nat;
  1222 
  1223 * recdef: a new declaration form, allows general recursive functions to be
  1224 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1225 
  1226 * the constant for negation has been renamed from "not" to "Not" to
  1227 harmonize with FOL, ZF, LK, etc.;
  1228 
  1229 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1230 infinite lists;
  1231 
  1232 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1233 
  1234 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1235 problems in commutative rings, using axiomatic type classes for + and *;
  1236 
  1237 * more examples in HOL/MiniML and HOL/Auth;
  1238 
  1239 * more default rewrite rules for quantifiers, union/intersection;
  1240 
  1241 * a new constant `arbitrary == @x.False';
  1242 
  1243 * HOLCF/IOA replaces old HOL/IOA;
  1244 
  1245 * HOLCF changes: derived all rules and arities
  1246   + axiomatic type classes instead of classes
  1247   + typedef instead of faking type definitions
  1248   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1249   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1250   + eliminated the types void, one, tr
  1251   + use unit lift and bool lift (with translations) instead of one and tr
  1252   + eliminated blift from Lift3.thy (use Def instead of blift)
  1253   all eliminated rules are derived as theorems --> no visible changes ;
  1254 
  1255 
  1256 *** ZF ***
  1257 
  1258 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1259 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1260 as ZF_cs addSIs [equalityI];
  1261 
  1262 
  1263 
  1264 New in Isabelle94-7 (November 96)
  1265 ---------------------------------
  1266 
  1267 * allowing negative levels (as offsets) in prlev and choplev;
  1268 
  1269 * super-linear speedup for large simplifications;
  1270 
  1271 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1272 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1273 FAIL); can suppress it using the command Delsimps (ex_simps @
  1274 all_simps); De Morgan laws are also now included, by default;
  1275 
  1276 * improved printing of ==>  :  ~:
  1277 
  1278 * new object-logic "Sequents" adds linear logic, while replacing LK
  1279 and Modal (thanks to Sara Kalvala);
  1280 
  1281 * HOL/Auth: correctness proofs for authentication protocols;
  1282 
  1283 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1284 examples on HOL/Auth);
  1285 
  1286 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1287 the rewriter and classical reasoner simultaneously;
  1288 
  1289 * function uresult no longer returns theorems in "standard" format;
  1290 regain previous version by: val uresult = standard o uresult;
  1291 
  1292 
  1293 
  1294 New in Isabelle94-6
  1295 -------------------
  1296 
  1297 * oracles -- these establish an interface between Isabelle and trusted
  1298 external reasoners, which may deliver results as theorems;
  1299 
  1300 * proof objects (in particular record all uses of oracles);
  1301 
  1302 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1303 
  1304 * "constdefs" section in theory files;
  1305 
  1306 * "primrec" section (HOL) no longer requires names;
  1307 
  1308 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1309 
  1310 
  1311 
  1312 New in Isabelle94-5
  1313 -------------------
  1314 
  1315 * reduced space requirements;
  1316 
  1317 * automatic HTML generation from theories;
  1318 
  1319 * theory files no longer require "..." (quotes) around most types;
  1320 
  1321 * new examples, including two proofs of the Church-Rosser theorem;
  1322 
  1323 * non-curried (1994) version of HOL is no longer distributed;
  1324 
  1325 
  1326 
  1327 New in Isabelle94-4
  1328 -------------------
  1329 
  1330 * greatly reduced space requirements;
  1331 
  1332 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1333 
  1334 * searchable theorem database (see the section "Retrieving theorems" on
  1335 page 8 of the Reference Manual);
  1336 
  1337 * new examples, including Grabczewski's monumental case study of the
  1338 Axiom of Choice;
  1339 
  1340 * The previous version of HOL renamed to Old_HOL;
  1341 
  1342 * The new version of HOL (previously called CHOL) uses a curried syntax
  1343 for functions.  Application looks like f a b instead of f(a,b);
  1344 
  1345 * Mutually recursive inductive definitions finally work in HOL;
  1346 
  1347 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1348 translates to the operator "split";
  1349 
  1350 
  1351 
  1352 New in Isabelle94-3
  1353 -------------------
  1354 
  1355 * new infix operator, addss, allowing the classical reasoner to
  1356 perform simplification at each step of its search.  Example:
  1357         fast_tac (cs addss ss)
  1358 
  1359 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1360 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1361 look like (a,b) instead of <a,b>;
  1362 
  1363 * PLEASE NOTE: CHOL will eventually replace HOL!
  1364 
  1365 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1366 It translates to the operator "split".  A new theory of integers is available;
  1367 
  1368 * In ZF, integer numerals now denote two's-complement binary integers.
  1369 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1370 
  1371 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1372 of the Axiom of Choice;
  1373 
  1374 
  1375 
  1376 New in Isabelle94-2
  1377 -------------------
  1378 
  1379 * Significantly faster resolution;
  1380 
  1381 * the different sections in a .thy file can now be mixed and repeated
  1382 freely;
  1383 
  1384 * Database of theorems for FOL, HOL and ZF.  New
  1385 commands including qed, qed_goal and bind_thm store theorems in the database.
  1386 
  1387 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1388 a given theory (thms_of), or find out what theory a theorem was proved in
  1389 (theory_of_thm);
  1390 
  1391 * Bugs fixed in the inductive definition and datatype packages;
  1392 
  1393 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1394 and HOL_dup_cs obsolete;
  1395 
  1396 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1397 have been removed;
  1398 
  1399 * Simpler definition of function space in ZF;
  1400 
  1401 * new results about cardinal and ordinal arithmetic in ZF;
  1402 
  1403 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1404 types;
  1405 
  1406 
  1407 $Id$