NEWS
author paulson
Thu Oct 16 10:32:06 2003 +0200 (2003-10-16)
changeset 14237 a486123e24a5
parent 14234 9590df3c5f2a
child 14243 0e2ec694784d
permissions -rw-r--r--
line-breaks; rewording
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Pure: Greek letters (except small lambda, \<lambda>), as well as gothic
    10   (\<aa>...\<zz>\<AA>...\<ZZ>), caligraphic (\<A>...\<Z>), and euler
    11   (\<a>...\<z>), are now considered normal letters, and can therefore
    12   be used anywhere where an ASCII letter (a...zA...Z) has until
    13   now. COMPATIBILITY: This obviously changes the parsing of some
    14   terms, especially where a symbol has been used as a binder, say
    15   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
    16   as an identifier.  Fix it by inserting a space around former
    17   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
    18   existing theory and ML files.
    19 
    20 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
    21 
    22 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now 
    23   allowed in identifiers. Similar to greek letters \<^isub> is now considered 
    24   a normal (but invisible) letter. For multiple letter subscripts repeat 
    25   \<^isub> like this: x\<^isub>1\<^isub>2. 
    26 
    27 * Pure: Using new Isar command "finalconsts" (or the ML functions
    28   Theory.add_finals or Theory.add_finals_i) it is now possible to
    29   declare constants "final", which prevents their being given a definition
    30   later.  It is useful for constants whose behaviour is fixed axiomatically
    31   rather than definitionally, such as the meta-logic connectives.
    32 
    33 *** Isar ***
    34 
    35 * Tactic emulation methods ?rule_tac, cut_tac, subgoal_tac and thin_tac:
    36   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    37     locales are no longer forced to write Isar proof scripts.
    38     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    39     emulations.
    40   - INCOMPATIBILITY: names of variables to be instantiated may no
    41     longer be enclosed in quotes.  Instead, precede variable name with `?'.
    42     This is consistent with the instantiation attribute "where".
    43 
    44 * Locales:
    45   - Goal statements involving the context element "includes" no longer
    46     generate theorems with internal delta predicates (those ending on
    47     "_axioms") in the premise.
    48     Resolve particular premise with <locale>.intro to obtain old form.
    49   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
    50     specification and "includes" elements in goal statement.
    51 
    52 * HOL: Tactic emulation methods induct_tac and case_tac understand static
    53   (Isar) contexts.
    54 
    55 *** HOL ***
    56 
    57 * 'specification' command added, allowing for definition by
    58   specification.  There is also an 'ax_specification' command that
    59   introduces the new constants axiomatically.
    60 
    61 * SET-Protocol: formalization and verification of the SET protocol suite;
    62 
    63 
    64 New in Isabelle2003 (May 2003)
    65 --------------------------------
    66 
    67 *** General ***
    68 
    69 * Provers/simplifier:
    70 
    71   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
    72     Assumptions are now subject to complete mutual simplification,
    73     not just from left to right. The simplifier now preserves
    74     the order of assumptions.
    75 
    76     Potential INCOMPATIBILITY:
    77 
    78     -- simp sometimes diverges where the old version did
    79        not, e.g. invoking simp on the goal
    80 
    81         [| P (f x); y = x; f x = f y |] ==> Q
    82 
    83        now gives rise to the infinite reduction sequence
    84 
    85         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
    86 
    87        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
    88        kind of problem.
    89 
    90     -- Tactics combining classical reasoner and simplification (such as auto)
    91        are also affected by this change, because many of them rely on
    92        simp. They may sometimes diverge as well or yield a different numbers
    93        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
    94        in case of problems. Sometimes subsequent calls to the classical
    95        reasoner will fail because a preceeding call to the simplifier too
    96        eagerly simplified the goal, e.g. deleted redundant premises.
    97 
    98   - The simplifier trace now shows the names of the applied rewrite rules
    99 
   100   - You can limit the number of recursive invocations of the simplifier
   101     during conditional rewriting (where the simplifie tries to solve the
   102     conditions before applying the rewrite rule):
   103     ML "simp_depth_limit := n"
   104     where n is an integer. Thus you can force termination where previously
   105     the simplifier would diverge.
   106 
   107   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   108 
   109   - No longer aborts on failed congruence proof.  Instead, the
   110     congruence is ignored.
   111 
   112 * Pure: New generic framework for extracting programs from constructive
   113   proofs. See HOL/Extraction.thy for an example instantiation, as well
   114   as HOL/Extraction for some case studies.
   115 
   116 * Pure: The main goal of the proof state is no longer shown by default, only
   117 the subgoals. This behaviour is controlled by a new flag.
   118    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   119 (ML: Proof.show_main_goal).
   120 
   121 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   122 rules whose conclusion matches subgoal 1:
   123       PG menu: Isabelle/Isar -> Show me -> matching rules
   124 The rules are ordered by how closely they match the subgoal.
   125 In particular, rules that solve a subgoal outright are displayed first
   126 (or rather last, the way they are printed).
   127 (ML: ProofGeneral.print_intros())
   128 
   129 * Pure: New flag trace_unify_fail causes unification to print
   130 diagnostic information (PG: in trace buffer) when it fails. This is
   131 useful for figuring out why single step proofs like rule, erule or
   132 assumption failed.
   133 
   134 * Pure: Locale specifications now produce predicate definitions
   135 according to the body of text (covering assumptions modulo local
   136 definitions); predicate "loc_axioms" covers newly introduced text,
   137 while "loc" is cumulative wrt. all included locale expressions; the
   138 latter view is presented only on export into the global theory
   139 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   140 on the old view without predicates;
   141 
   142 * Pure: predefined locales "var" and "struct" are useful for sharing
   143 parameters (as in CASL, for example); just specify something like
   144 ``var x + var y + struct M'' as import;
   145 
   146 * Pure: improved thms_containing: proper indexing of facts instead of
   147 raw theorems; check validity of results wrt. current name space;
   148 include local facts of proof configuration (also covers active
   149 locales), cover fixed variables in index; may use "_" in term
   150 specification; an optional limit for the number of printed facts may
   151 be given (the default is 40);
   152 
   153 * Pure: disallow duplicate fact bindings within new-style theory files
   154 (batch-mode only);
   155 
   156 * Provers: improved induct method: assumptions introduced by case
   157 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   158 the goal statement); "foo" still refers to all facts collectively;
   159 
   160 * Provers: the function blast.overloaded has been removed: all constants
   161 are regarded as potentially overloaded, which improves robustness in exchange
   162 for slight decrease in efficiency;
   163 
   164 * Provers/linorder: New generic prover for transitivity reasoning over
   165 linear orders.  Note: this prover is not efficient!
   166 
   167 * Isar: preview of problems to finish 'show' now produce an error
   168 rather than just a warning (in interactive mode);
   169 
   170 
   171 *** HOL ***
   172 
   173 * arith(_tac)
   174 
   175  - Produces a counter example if it cannot prove a goal.
   176    Note that the counter example may be spurious if the goal is not a formula
   177    of quantifier-free linear arithmetic.
   178    In ProofGeneral the counter example appears in the trace buffer.
   179 
   180  - Knows about div k and mod k where k is a numeral of type nat or int.
   181 
   182  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   183    linear arithmetic fails. This takes account of quantifiers and divisibility.
   184    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   185 
   186 * simp's arithmetic capabilities have been enhanced a bit: it now
   187 takes ~= in premises into account (by performing a case split);
   188 
   189 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   190 are distributed over a sum of terms;
   191 
   192 * New tactic "trans_tac" and method "trans" instantiate
   193 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   194 "<=", "<" and "="). 
   195 
   196 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   197 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   198 
   199 * 'typedef' command has new option "open" to suppress the set
   200 definition;
   201 
   202 * functions Min and Max on finite sets have been introduced (theory
   203 Finite_Set);
   204 
   205 * attribute [symmetric] now works for relations as well; it turns
   206 (x,y) : R^-1 into (y,x) : R, and vice versa;
   207 
   208 * induct over a !!-quantified statement (say !!x1..xn):
   209   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   210 
   211 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   212 %x. None. Warning: empty_def now refers to the previously hidden definition
   213 of the empty set.
   214 
   215 * Algebra: formalization of classical algebra.  Intended as base for
   216 any algebraic development in Isabelle.  Currently covers group theory
   217 (up to Sylow's theorem) and ring theory (Universal Property of
   218 Univariate Polynomials).  Contributions welcome;
   219 
   220 * GroupTheory: deleted, since its material has been moved to Algebra;
   221 
   222 * Complex: new directory of the complex numbers with numeric constants, 
   223 nonstandard complex numbers, and some complex analysis, standard and 
   224 nonstandard (Jacques Fleuriot);
   225 
   226 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   227 
   228 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   229 Fleuriot);
   230 
   231 * Real/HahnBanach: updated and adapted to locales;
   232 
   233 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   234 Gray and Kramer);
   235 
   236 * UNITY: added the Meier-Sanders theory of progress sets;
   237 
   238 * MicroJava: bytecode verifier and lightweight bytecode verifier
   239 as abstract algorithms, instantiated to the JVM;
   240 
   241 * Bali: Java source language formalization. Type system, operational
   242 semantics, axiomatic semantics. Supported language features:
   243 classes, interfaces, objects,virtual methods, static methods,
   244 static/instance fields, arrays, access modifiers, definite
   245 assignment, exceptions.
   246 
   247 
   248 *** ZF ***
   249 
   250 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   251 universe, etc.);
   252 
   253 * Main ZF: virtually all theories converted to new-style format;
   254 
   255 
   256 *** ML ***
   257 
   258 * Pure: Tactic.prove provides sane interface for internal proofs;
   259 omits the infamous "standard" operation, so this is more appropriate
   260 than prove_goalw_cterm in many situations (e.g. in simprocs);
   261 
   262 * Pure: improved error reporting of simprocs;
   263 
   264 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   265 up simprocs;
   266 
   267 
   268 *** Document preparation ***
   269 
   270 * uses \par instead of \\ for line breaks in theory text. This may
   271 shift some page breaks in large documents. To get the old behaviour
   272 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   273 
   274 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   275 other packages
   276 
   277 * \<euro> now needs package babel/greek instead of marvosym (which
   278 broke \Rightarrow)
   279 
   280 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   281 textcomp package)
   282 
   283 
   284 New in Isabelle2002 (March 2002)
   285 --------------------------------
   286 
   287 *** Document preparation ***
   288 
   289 * greatly simplified document preparation setup, including more
   290 graceful interpretation of isatool usedir -i/-d/-D options, and more
   291 instructive isatool mkdir; users should basically be able to get
   292 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   293 users may run a separate document processing stage manually like this:
   294 "isatool usedir -D output HOL Test && isatool document Test/output";
   295 
   296 * theory dependency graph may now be incorporated into documents;
   297 isatool usedir -g true will produce session_graph.eps/.pdf for use
   298 with \includegraphics of LaTeX;
   299 
   300 * proper spacing of consecutive markup elements, especially text
   301 blocks after section headings;
   302 
   303 * support bold style (for single symbols only), input syntax is like
   304 this: "\<^bold>\<alpha>" or "\<^bold>A";
   305 
   306 * \<bullet> is now output as bold \cdot by default, which looks much
   307 better in printed text;
   308 
   309 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   310 note that these symbols are currently unavailable in Proof General /
   311 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   312 
   313 * isatool latex no longer depends on changed TEXINPUTS, instead
   314 isatool document copies the Isabelle style files to the target
   315 location;
   316 
   317 
   318 *** Isar ***
   319 
   320 * Pure/Provers: improved proof by cases and induction;
   321   - 'case' command admits impromptu naming of parameters (such as
   322     "case (Suc n)");
   323   - 'induct' method divinates rule instantiation from the inductive
   324     claim; no longer requires excessive ?P bindings for proper
   325     instantiation of cases;
   326   - 'induct' method properly enumerates all possibilities of set/type
   327     rules; as a consequence facts may be also passed through *type*
   328     rules without further ado;
   329   - 'induct' method now derives symbolic cases from the *rulified*
   330     rule (before it used to rulify cases stemming from the internal
   331     atomized version); this means that the context of a non-atomic
   332     statement becomes is included in the hypothesis, avoiding the
   333     slightly cumbersome show "PROP ?case" form;
   334   - 'induct' may now use elim-style induction rules without chaining
   335     facts, using ``missing'' premises from the goal state; this allows
   336     rules stemming from inductive sets to be applied in unstructured
   337     scripts, while still benefitting from proper handling of non-atomic
   338     statements; NB: major inductive premises need to be put first, all
   339     the rest of the goal is passed through the induction;
   340   - 'induct' proper support for mutual induction involving non-atomic
   341     rule statements (uses the new concept of simultaneous goals, see
   342     below);
   343   - append all possible rule selections, but only use the first
   344     success (no backtracking);
   345   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   346   - undeclared rule case names default to numbers 1, 2, 3, ...;
   347   - added 'print_induct_rules' (covered by help item in recent Proof
   348     General versions);
   349   - moved induct/cases attributes to Pure, methods to Provers;
   350   - generic method setup instantiated for FOL and HOL;
   351 
   352 * Pure: support multiple simultaneous goal statements, for example
   353 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   354 meta-level mechanism, this acts as if several individual goals had
   355 been stated separately; in particular common proof methods need to be
   356 repeated in order to cover all claims; note that a single elimination
   357 step is *not* sufficient to establish the two conjunctions, so this
   358 fails:
   359 
   360   assume "A & B" then have A and B ..   (*".." fails*)
   361 
   362 better use "obtain" in situations as above; alternative refer to
   363 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   364 
   365 * Pure: proper integration with ``locales''; unlike the original
   366 version by Florian Kammüller, Isar locales package high-level proof
   367 contexts rather than raw logical ones (e.g. we admit to include
   368 attributes everywhere); operations on locales include merge and
   369 rename; support for implicit arguments (``structures''); simultaneous
   370 type-inference over imports and text; see also HOL/ex/Locales.thy for
   371 some examples;
   372 
   373 * Pure: the following commands have been ``localized'', supporting a
   374 target locale specification "(in name)": 'lemma', 'theorem',
   375 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   376 stored both within the locale and at the theory level (exported and
   377 qualified by the locale name);
   378 
   379 * Pure: theory goals may now be specified in ``long'' form, with
   380 ad-hoc contexts consisting of arbitrary locale elements. for example
   381 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   382 definitions may be given, too); the result is a meta-level rule with
   383 the context elements being discharged in the obvious way;
   384 
   385 * Pure: new proof command 'using' allows to augment currently used
   386 facts after a goal statement ('using' is syntactically analogous to
   387 'apply', but acts on the goal's facts only); this allows chained facts
   388 to be separated into parts given before and after a claim, as in
   389 ``from a and b have C using d and e <proof>'';
   390 
   391 * Pure: renamed "antecedent" case to "rule_context";
   392 
   393 * Pure: new 'judgment' command records explicit information about the
   394 object-logic embedding (used by several tools internally); no longer
   395 use hard-wired "Trueprop";
   396 
   397 * Pure: added 'corollary' command;
   398 
   399 * Pure: fixed 'token_translation' command;
   400 
   401 * Pure: removed obsolete 'exported' attribute;
   402 
   403 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   404 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   405 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   406 
   407 * Pure: method 'atomize' presents local goal premises as object-level
   408 statements (atomic meta-level propositions); setup controlled via
   409 rewrite rules declarations of 'atomize' attribute; example
   410 application: 'induct' method with proper rule statements in improper
   411 proof *scripts*;
   412 
   413 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   414 now consider the syntactic context of assumptions, giving a better
   415 chance to get type-inference of the arguments right (this is
   416 especially important for locales);
   417 
   418 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   419 mode;
   420 
   421 * Pure/obtain: the formal conclusion "thesis", being marked as
   422 ``internal'', may no longer be reference directly in the text;
   423 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   424 situations;
   425 
   426 * Pure: generic 'sym' attribute which declares a rule both as pure
   427 'elim?' and for the 'symmetric' operation;
   428 
   429 * Pure: marginal comments ``--'' may now occur just anywhere in the
   430 text; the fixed correlation with particular command syntax has been
   431 discontinued;
   432 
   433 * Pure: new method 'rules' is particularly well-suited for proof
   434 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   435 but often produces more compact proof terms with less detours;
   436 
   437 * Pure/Provers/classical: simplified integration with pure rule
   438 attributes and methods; the classical "intro?/elim?/dest?"
   439 declarations coincide with the pure ones; the "rule" method no longer
   440 includes classically swapped intros; "intro" and "elim" methods no
   441 longer pick rules from the context; also got rid of ML declarations
   442 AddXIs/AddXEs/AddXDs; all of this has some potential for
   443 INCOMPATIBILITY;
   444 
   445 * Provers/classical: attribute 'swapped' produces classical inversions
   446 of introduction rules;
   447 
   448 * Provers/simplifier: 'simplified' attribute may refer to explicit
   449 rules instead of full simplifier context; 'iff' attribute handles
   450 conditional rules;
   451 
   452 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   453 
   454 * HOL: 'recdef' now fails on unfinished automated proofs, use
   455 "(permissive)" option to recover old behavior;
   456 
   457 * HOL: 'inductive' no longer features separate (collective) attributes
   458 for 'intros' (was found too confusing);
   459 
   460 * HOL: properly declared induction rules less_induct and
   461 wf_induct_rule;
   462 
   463 
   464 *** HOL ***
   465 
   466 * HOL: moved over to sane numeral syntax; the new policy is as
   467 follows:
   468 
   469   - 0 and 1 are polymorphic constants, which are defined on any
   470   numeric type (nat, int, real etc.);
   471 
   472   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   473   binary representation internally;
   474 
   475   - type nat has special constructor Suc, and generally prefers Suc 0
   476   over 1::nat and Suc (Suc 0) over 2::nat;
   477 
   478 This change may cause significant problems of INCOMPATIBILITY; here
   479 are some hints on converting existing sources:
   480 
   481   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   482   entities, so expressions involving "-" (unary or binary minus) need
   483   to be spaced properly;
   484 
   485   - existing occurrences of "1" may need to be constraint "1::nat" or
   486   even replaced by Suc 0; similar for old "2";
   487 
   488   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   489 
   490   - remove all special provisions on numerals in proofs;
   491 
   492 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   493 representation (depends on bin_arith_simps in the default context);
   494 
   495 * HOL: symbolic syntax for x^2 (numeral 2);
   496 
   497 * HOL: the class of all HOL types is now called "type" rather than
   498 "term"; INCOMPATIBILITY, need to adapt references to this type class
   499 in axclass/classes, instance/arities, and (usually rare) occurrences
   500 in typings (of consts etc.); internally the class is called
   501 "HOL.type", ML programs should refer to HOLogic.typeS;
   502 
   503 * HOL/record package improvements:
   504   - new derived operations "fields" to build a partial record section,
   505     "extend" to promote a fixed record to a record scheme, and
   506     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   507     declared as simp by default;
   508   - shared operations ("more", "fields", etc.) now need to be always
   509     qualified) --- potential INCOMPATIBILITY;
   510   - removed "make_scheme" operations (use "make" with "extend") --
   511     INCOMPATIBILITY;
   512   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   513   - provides cases/induct rules for use with corresponding Isar
   514     methods (for concrete records, record schemes, concrete more
   515     parts, and schematic more parts -- in that order);
   516   - internal definitions directly based on a light-weight abstract
   517     theory of product types over typedef rather than datatype;
   518 
   519 * HOL: generic code generator for generating executable ML code from
   520 specifications; specific support for HOL constructs such as inductive
   521 datatypes and sets, as well as recursive functions; can be invoked
   522 via 'generate_code' theory section;
   523 
   524 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   525 
   526 * HOL: consolidated and renamed several theories.  In particular:
   527 	Ord.thy has been absorbed into HOL.thy
   528 	String.thy has been absorbed into List.thy
   529  
   530 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   531 (beware of argument permutation!);
   532 
   533 * HOL: linorder_less_split superseded by linorder_cases;
   534 
   535 * HOL/List: "nodups" renamed to "distinct";
   536 
   537 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   538 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   539   - Ex_def has changed, now need to use some_eq_ex
   540 
   541 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   542 in this (rare) case use:
   543 
   544   delSWrapper "split_all_tac"
   545   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   546 
   547 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   548 MAY FAIL;
   549 
   550 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   551 Isabelle's type classes, ^ on functions and relations has too general
   552 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   553 necessary to attach explicit type constraints;
   554 
   555 * HOL/Relation: the prefix name of the infix "O" has been changed from
   556 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   557 renamed accordingly (eg "compI" -> "rel_compI").
   558 
   559 * HOL: syntax translations now work properly with numerals and records
   560 expressions;
   561 
   562 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   563 of "lam" -- INCOMPATIBILITY;
   564 
   565 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   566 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   567 renamed "Product_Type.unit";
   568 
   569 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   570 
   571 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   572 the "cases" method);
   573 
   574 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   575 Florian Kammüller);
   576 
   577 * HOL/IMP: updated and converted to new-style theory format; several
   578 parts turned into readable document, with proper Isar proof texts and
   579 some explanations (by Gerwin Klein);
   580 
   581 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   582 
   583 * HOL-Hyperreal is now a logic image;
   584 
   585 
   586 *** HOLCF ***
   587 
   588 * Isar: consts/constdefs supports mixfix syntax for continuous
   589 operations;
   590 
   591 * Isar: domain package adapted to new-style theory format, e.g. see
   592 HOLCF/ex/Dnat.thy;
   593 
   594 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   595 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   596 lift.induct_tac, always use UU instead of Undef;
   597 
   598 * HOLCF/IMP: updated and converted to new-style theory;
   599 
   600 
   601 *** ZF ***
   602 
   603 * Isar: proper integration of logic-specific tools and packages,
   604 including theory commands '(co)inductive', '(co)datatype',
   605 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   606 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   607 
   608 * theory Main no longer includes AC; for the Axiom of Choice, base
   609 your theory on Main_ZFC;
   610 
   611 * the integer library now covers quotients and remainders, with many
   612 laws relating division to addition, multiplication, etc.;
   613 
   614 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   615 typeless version of the formalism;
   616 
   617 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   618 format;
   619 
   620 * ZF/Induct: new directory for examples of inductive definitions,
   621 including theory Multiset for multiset orderings; converted to
   622 new-style theory format;
   623 
   624 * ZF: many new theorems about lists, ordinals, etc.;
   625 
   626 
   627 *** General ***
   628 
   629 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   630 variable proof controls level of detail: 0 = no proofs (only oracle
   631 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   632 also ref manual for further ML interfaces;
   633 
   634 * Pure/axclass: removed obsolete ML interface
   635 goal_subclass/goal_arity;
   636 
   637 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   638 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   639 separate tokens, so expressions involving minus need to be spaced
   640 properly;
   641 
   642 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   643 rather than "infixl" or "infixr";
   644 
   645 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   646 sort constraint specifications in type inference; e.g. "x::_::foo"
   647 ensures that the type of "x" is of sort "foo" (but not necessarily a
   648 type variable);
   649 
   650 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   651 control output of nested => (types); the default behavior is
   652 "type_brackets";
   653 
   654 * Pure/syntax: builtin parse translation for "_constify" turns valued
   655 tokens into AST constants;
   656 
   657 * Pure/syntax: prefer later declarations of translations and print
   658 translation functions; potential INCOMPATIBILITY: need to reverse
   659 multiple declarations for same syntax element constant;
   660 
   661 * Pure/show_hyps reset by default (in accordance to existing Isar
   662 practice);
   663 
   664 * Provers/classical: renamed addaltern to addafter, addSaltern to
   665 addSafter;
   666 
   667 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   668 as well;
   669 
   670 * system: tested support for MacOS X; should be able to get Isabelle +
   671 Proof General to work in a plain Terminal after installing Poly/ML
   672 (e.g. from the Isabelle distribution area) and GNU bash alone
   673 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   674 support requires further installations, e.g. from
   675 http://fink.sourceforge.net/);
   676 
   677 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   678 
   679 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   680 of 40 MB), cf. ML_OPTIONS;
   681 
   682 * system: Proof General keywords specification is now part of the
   683 Isabelle distribution (see etc/isar-keywords.el);
   684 
   685 * system: support for persistent Proof General sessions (refrain from
   686 outdating all loaded theories on startup); user may create writable
   687 logic images like this: ``isabelle -q HOL Test'';
   688 
   689 * system: smart selection of Isabelle process versus Isabelle
   690 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   691 run both "isabelle" and "Isabelle" even if file names are badly
   692 damaged (executable inspects the case of the first letter of its own
   693 name); added separate "isabelle-process" and "isabelle-interface";
   694 
   695 * system: refrain from any attempt at filtering input streams; no
   696 longer support ``8bit'' encoding of old isabelle font, instead proper
   697 iso-latin characters may now be used; the related isatools
   698 "symbolinput" and "nonascii" have disappeared as well;
   699 
   700 * system: removed old "xterm" interface (the print modes "xterm" and
   701 "xterm_color" are still available for direct use in a suitable
   702 terminal);
   703 
   704 
   705 
   706 New in Isabelle99-2 (February 2001)
   707 -----------------------------------
   708 
   709 *** Overview of INCOMPATIBILITIES ***
   710 
   711 * HOL: please note that theories in the Library and elsewhere often use the
   712 new-style (Isar) format; to refer to their theorems in an ML script you must
   713 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   714 
   715 * HOL: inductive package no longer splits induction rule aggressively,
   716 but only as far as specified by the introductions given; the old
   717 format may be recovered via ML function complete_split_rule or attribute
   718 'split_rule (complete)';
   719 
   720 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   721 gfp_Tarski to gfp_unfold;
   722 
   723 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   724 
   725 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   726 relation); infix "^^" has been renamed "``"; infix "``" has been
   727 renamed "`"; "univalent" has been renamed "single_valued";
   728 
   729 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   730 operation;
   731 
   732 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   733 
   734 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   735 
   736 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   737 consequence, it is no longer monotonic wrt. the local goal context
   738 (which is now passed through the inductive cases);
   739 
   740 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   741 \<gg> to \<ggreater>;
   742 
   743 
   744 *** Document preparation ***
   745 
   746 * \isabellestyle{NAME} selects version of Isabelle output (currently
   747 available: are "it" for near math-mode best-style output, "sl" for
   748 slanted text style, and "tt" for plain type-writer; if no
   749 \isabellestyle command is given, output is according to slanted
   750 type-writer);
   751 
   752 * support sub/super scripts (for single symbols only), input syntax is
   753 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   754 
   755 * some more standard symbols; see Appendix A of the system manual for
   756 the complete list of symbols defined in isabellesym.sty;
   757 
   758 * improved isabelle style files; more abstract symbol implementation
   759 (should now use \isamath{...} and \isatext{...} in custom symbol
   760 definitions);
   761 
   762 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   763 state; Note that presentation of goal states does not conform to
   764 actual human-readable proof documents.  Please do not include goal
   765 states into document output unless you really know what you are doing!
   766 
   767 * proper indentation of antiquoted output with proportional LaTeX
   768 fonts;
   769 
   770 * no_document ML operator temporarily disables LaTeX document
   771 generation;
   772 
   773 * isatool unsymbolize tunes sources for plain ASCII communication;
   774 
   775 
   776 *** Isar ***
   777 
   778 * Pure: Isar now suffers initial goal statements to contain unbound
   779 schematic variables (this does not conform to actual readable proof
   780 documents, due to unpredictable outcome and non-compositional proof
   781 checking); users who know what they are doing may use schematic goals
   782 for Prolog-style synthesis of proven results;
   783 
   784 * Pure: assumption method (an implicit finishing) now handles actual
   785 rules as well;
   786 
   787 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   788 initial goal, declare "that" only as Pure intro (only for single
   789 steps); the "that" rule assumption may now be involved in implicit
   790 finishing, thus ".." becomes a feasible for trivial obtains;
   791 
   792 * Pure: default proof step now includes 'intro_classes'; thus trivial
   793 instance proofs may be performed by "..";
   794 
   795 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   796 statements as well;
   797 
   798 * Pure: more robust selection of calculational rules;
   799 
   800 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   801 rule (as well as the assumption rule);
   802 
   803 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   804 lemmas, using the graph browser tool;
   805 
   806 * Pure: predict failure of "show" in interactive mode;
   807 
   808 * Pure: 'thms_containing' now takes actual terms as arguments;
   809 
   810 * HOL: improved method 'induct' --- now handles non-atomic goals
   811 (potential INCOMPATIBILITY); tuned error handling;
   812 
   813 * HOL: cases and induct rules now provide explicit hints about the
   814 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   815 any remaining facts are inserted into the goal verbatim;
   816 
   817 * HOL: local contexts (aka cases) may now contain term bindings as
   818 well; the 'cases' and 'induct' methods new provide a ?case binding for
   819 the result to be shown in each case;
   820 
   821 * HOL: added 'recdef_tc' command;
   822 
   823 * isatool convert assists in eliminating legacy ML scripts;
   824 
   825 
   826 *** HOL ***
   827 
   828 * HOL/Library: a collection of generic theories to be used together
   829 with main HOL; the theory loader path already includes this directory
   830 by default; the following existing theories have been moved here:
   831 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   832 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   833 
   834 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   835 modelling and verification task performed in Isabelle/HOL +
   836 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   837 
   838 * HOL/Algebra: special summation operator SUM no longer exists, it has
   839 been replaced by setsum; infix 'assoc' now has priority 50 (like
   840 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   841 'domain', this makes the theory consistent with mathematical
   842 literature;
   843 
   844 * HOL basics: added overloaded operations "inverse" and "divide"
   845 (infix "/"), syntax for generic "abs" operation, generic summation
   846 operator \<Sum>;
   847 
   848 * HOL/typedef: simplified package, provide more useful rules (see also
   849 HOL/subset.thy);
   850 
   851 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   852 now expressed as a proper nested rule (old-style tactic scripts may
   853 require atomize_strip_tac to cope with non-atomic premises);
   854 
   855 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   856 to "split_conv" (old name still available for compatibility);
   857 
   858 * HOL: improved concrete syntax for strings (e.g. allows translation
   859 rules with string literals);
   860 
   861 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   862  and Fleuriot's mechanization of analysis, including the transcendental
   863  functions for the reals;
   864 
   865 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   866 
   867 
   868 *** CTT ***
   869 
   870 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   871 "lam" is displayed as TWO lambda-symbols
   872 
   873 * CTT: theory Main now available, containing everything (that is, Bool
   874 and Arith);
   875 
   876 
   877 *** General ***
   878 
   879 * Pure: the Simplifier has been implemented properly as a derived rule
   880 outside of the actual kernel (at last!); the overall performance
   881 penalty in practical applications is about 50%, while reliability of
   882 the Isabelle inference kernel has been greatly improved;
   883 
   884 * print modes "brackets" and "no_brackets" control output of nested =>
   885 (types) and ==> (props); the default behaviour is "brackets";
   886 
   887 * Provers: fast_tac (and friends) now handle actual object-logic rules
   888 as assumptions as well;
   889 
   890 * system: support Poly/ML 4.0;
   891 
   892 * system: isatool install handles KDE version 1 or 2;
   893 
   894 
   895 
   896 New in Isabelle99-1 (October 2000)
   897 ----------------------------------
   898 
   899 *** Overview of INCOMPATIBILITIES ***
   900 
   901 * HOL: simplification of natural numbers is much changed; to partly
   902 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   903 issue the following ML commands:
   904 
   905   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   906   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   907 
   908 * HOL: simplification no longer dives into case-expressions; this is
   909 controlled by "t.weak_case_cong" for each datatype t;
   910 
   911 * HOL: nat_less_induct renamed to less_induct;
   912 
   913 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   914 fixsome to patch .thy and .ML sources automatically;
   915 
   916   select_equality  -> some_equality
   917   select_eq_Ex     -> some_eq_ex
   918   selectI2EX       -> someI2_ex
   919   selectI2         -> someI2
   920   selectI          -> someI
   921   select1_equality -> some1_equality
   922   Eps_sym_eq       -> some_sym_eq_trivial
   923   Eps_eq           -> some_eq_trivial
   924 
   925 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   926 
   927 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   928 instead);
   929 
   930 * HOL: the recursion equations generated by 'recdef' are now called
   931 f.simps instead of f.rules;
   932 
   933 * HOL: qed_spec_mp now also handles bounded ALL as well;
   934 
   935 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   936 sometimes be needed;
   937 
   938 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   939 
   940 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   941 
   942 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   943 product is now "<*>" instead of "Times"; the lexicographic product is
   944 now "<*lex*>" instead of "**";
   945 
   946 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   947 of main HOL, but was unused); better use HOL's datatype package;
   948 
   949 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   950 the old syntax may be recovered as follows:
   951 
   952   syntax (symbols)
   953     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   954       (infixl "\\<oplus>" 100)
   955 
   956 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   957 
   958 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   959 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   960 internally;
   961 
   962 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   963 changed from A/r to A//r;
   964 
   965 * ZF: new treatment of arithmetic (nat & int) may break some old
   966 proofs;
   967 
   968 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   969 rulify -> rule_format, elimify -> elim_format, ...);
   970 
   971 * Isar/Provers: intro/elim/dest attributes changed; renamed
   972 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   973 should have to change intro!! to intro? only); replaced "delrule" by
   974 "rule del";
   975 
   976 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   977 
   978 * Provers: strengthened force_tac by using new first_best_tac;
   979 
   980 * LaTeX document preparation: several changes of isabelle.sty (see
   981 lib/texinputs);
   982 
   983 
   984 *** Document preparation ***
   985 
   986 * formal comments (text blocks etc.) in new-style theories may now
   987 contain antiquotations of thm/prop/term/typ/text to be presented
   988 according to latex print mode; concrete syntax is like this:
   989 @{term[show_types] "f(x) = a + x"};
   990 
   991 * isatool mkdir provides easy setup of Isabelle session directories,
   992 including proper document sources;
   993 
   994 * generated LaTeX sources are now deleted after successful run
   995 (isatool document -c); may retain a copy somewhere else via -D option
   996 of isatool usedir;
   997 
   998 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   999 style files, achieving self-contained LaTeX sources and simplifying
  1000 LaTeX debugging;
  1001 
  1002 * old-style theories now produce (crude) LaTeX output as well;
  1003 
  1004 * browser info session directories are now self-contained (may be put
  1005 on WWW server seperately); improved graphs of nested sessions; removed
  1006 graph for 'all sessions';
  1007 
  1008 * several improvements in isabelle style files; \isabellestyle{it}
  1009 produces fake math mode output; \isamarkupheader is now \section by
  1010 default; see lib/texinputs/isabelle.sty etc.;
  1011 
  1012 
  1013 *** Isar ***
  1014 
  1015 * Isar/Pure: local results and corresponding term bindings are now
  1016 subject to Hindley-Milner polymorphism (similar to ML); this
  1017 accommodates incremental type-inference very nicely;
  1018 
  1019 * Isar/Pure: new derived language element 'obtain' supports
  1020 generalized existence reasoning;
  1021 
  1022 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1023 support accumulation of results, without applying any rules yet;
  1024 useful to collect intermediate results without explicit name
  1025 references, and for use with transitivity rules with more than 2
  1026 premises;
  1027 
  1028 * Isar/Pure: scalable support for case-analysis type proofs: new
  1029 'case' language element refers to local contexts symbolically, as
  1030 produced by certain proof methods; internally, case names are attached
  1031 to theorems as "tags";
  1032 
  1033 * Isar/Pure: theory command 'hide' removes declarations from
  1034 class/type/const name spaces;
  1035 
  1036 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1037 indicate potential overloading;
  1038 
  1039 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1040 
  1041 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1042 "{a,b,c}" instead of {a,b,c};
  1043 
  1044 * Isar/Pure now provides its own version of intro/elim/dest
  1045 attributes; useful for building new logics, but beware of confusion
  1046 with the version in Provers/classical;
  1047 
  1048 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1049 case name 'antecedent';
  1050 
  1051 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1052 to the current context is now done automatically);
  1053 
  1054 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1055 for definining proof methods in ML;
  1056 
  1057 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1058 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1059 most cases, one should have to change intro!! to intro? only);
  1060 replaced "delrule" by "rule del";
  1061 
  1062 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1063 'symmetric' attribute (the latter supercedes [RS sym]);
  1064 
  1065 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1066 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1067 well (including splits);
  1068 
  1069 * Isar/Provers: Simplifier and Classical methods now support all kind
  1070 of modifiers used in the past, including 'cong', 'iff', etc.
  1071 
  1072 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1073 of Simplifier and Classical reasoner);
  1074 
  1075 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1076 now support named cases; major packages (inductive, datatype, primrec,
  1077 recdef) support case names and properly name parameters;
  1078 
  1079 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1080 monotonicity conditions are extracted to be proven at end of
  1081 calculations;
  1082 
  1083 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1084 method anyway;
  1085 
  1086 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1087 split_if split_if_asm; datatype package provides theorems foo.splits =
  1088 foo.split foo.split_asm for each datatype;
  1089 
  1090 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1091 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1092 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1093 use "(cases (simplified))" method in proper proof texts);
  1094 
  1095 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1096 
  1097 * Isar: names of theorems etc. may be natural numbers as well;
  1098 
  1099 * Isar: 'pr' command: optional arguments for goals_limit and
  1100 ProofContext.prems_limit; no longer prints theory contexts, but only
  1101 proof states;
  1102 
  1103 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1104 additional print modes to be specified; e.g. "pr(latex)" will print
  1105 proof state according to the Isabelle LaTeX style;
  1106 
  1107 * Isar: improved support for emulating tactic scripts, including proof
  1108 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1109 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1110 (for HOL datatypes);
  1111 
  1112 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1113 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1114 'proof method scripts' have to be in depth-first order;
  1115 
  1116 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1117 
  1118 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1119 should instead use individual commands for printing items
  1120 (print_commands, print_methods etc.);
  1121 
  1122 * Isar: added 'nothing' --- the empty list of theorems;
  1123 
  1124 
  1125 *** HOL ***
  1126 
  1127 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1128 corresponding virtual machine and a specification of its bytecode
  1129 verifier and a lightweight bytecode verifier, including proofs of
  1130 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1131 Cornelia Pusch (see also the homepage of project Bali at
  1132 http://isabelle.in.tum.de/Bali/);
  1133 
  1134 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1135 Clemens Ballarin;
  1136 
  1137 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1138 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1139 Rasmussen;
  1140 
  1141 * HOL/Lattice: fundamental concepts of lattice theory and order
  1142 structures, including duals, properties of bounds versus algebraic
  1143 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1144 Theorem for complete lattices etc.; may also serve as a demonstration
  1145 for abstract algebraic reasoning using axiomatic type classes, and
  1146 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1147 
  1148 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1149 von Oheimb;
  1150 
  1151 * HOL/IMPP: extension of IMP with local variables and mutually
  1152 recursive procedures, by David von Oheimb;
  1153 
  1154 * HOL/Lambda: converted into new-style theory and document;
  1155 
  1156 * HOL/ex/Multiquote: example of multiple nested quotations and
  1157 anti-quotations -- basically a generalized version of de-Bruijn
  1158 representation; very useful in avoiding lifting of operations;
  1159 
  1160 * HOL/record: added general record equality rule to simpset; fixed
  1161 select-update simplification procedure to handle extended records as
  1162 well; admit "r" as field name;
  1163 
  1164 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1165 other numeric types and also as the identity of groups, rings, etc.;
  1166 
  1167 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1168 Types nat and int belong to this axclass;
  1169 
  1170 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1171    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1172    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1173   two terms #m*u and #n*u are replaced by #(m+n)*u
  1174     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1175   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1176     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1177 
  1178 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1179 powerful prover for predicate logic but knows nothing of clasets; see
  1180 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1181 
  1182 * HOL: new version of "case_tac" subsumes both boolean case split and
  1183 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1184 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1185 
  1186 * HOL: simplification no longer dives into case-expressions: only the
  1187 selector expression is simplified, but not the remaining arms; to
  1188 enable full simplification of case-expressions for datatype t, you may
  1189 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1190 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1191 
  1192 * HOL/recdef: the recursion equations generated by 'recdef' for
  1193 function 'f' are now called f.simps instead of f.rules; if all
  1194 termination conditions are proved automatically, these simplification
  1195 rules are added to the simpset, as in primrec; rules may be named
  1196 individually as well, resulting in a separate list of theorems for
  1197 each equation;
  1198 
  1199 * HOL/While is a new theory that provides a while-combinator. It
  1200 permits the definition of tail-recursive functions without the
  1201 provision of a termination measure. The latter is necessary once the
  1202 invariant proof rule for while is applied.
  1203 
  1204 * HOL: new (overloaded) notation for the set of elements below/above
  1205 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1206 
  1207 * HOL: theorems impI, allI, ballI bound as "strip";
  1208 
  1209 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1210 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1211 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1212 
  1213 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1214 
  1215 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1216 main HOL, but was unused);
  1217 
  1218 * HOL: fewer consts declared as global (e.g. have to refer to
  1219 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1220 
  1221 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1222 in case of overlap with user translations (e.g. judgements over
  1223 tuples); (note that the underlying logical represenation is still
  1224 bogus);
  1225 
  1226 
  1227 *** ZF ***
  1228 
  1229 * ZF: simplification automatically cancels common terms in arithmetic
  1230 expressions over nat and int;
  1231 
  1232 * ZF: new treatment of nat to minimize type-checking: all operators
  1233 coerce their operands to a natural number using the function natify,
  1234 making the algebraic laws unconditional;
  1235 
  1236 * ZF: as above, for int: operators coerce their operands to an integer
  1237 using the function intify;
  1238 
  1239 * ZF: the integer library now contains many of the usual laws for the
  1240 orderings, including $<=, and monotonicity laws for $+ and $*;
  1241 
  1242 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1243 simplification;
  1244 
  1245 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1246 to the simplifier and classical reasoner simultaneously;
  1247 
  1248 
  1249 *** General ***
  1250 
  1251 * Provers: blast_tac now handles actual object-logic rules as
  1252 assumptions; note that auto_tac uses blast_tac internally as well;
  1253 
  1254 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1255 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1256 
  1257 * Provers: delrules now handles destruct rules as well (no longer need
  1258 explicit make_elim);
  1259 
  1260 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1261   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1262 use instead the strong form,
  1263   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1264 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1265 from destruct-rules;
  1266 
  1267 * Provers: Simplifier.easy_setup provides a fast path to basic
  1268 Simplifier setup for new object-logics;
  1269 
  1270 * Pure: AST translation rules no longer require constant head on LHS;
  1271 
  1272 * Pure: improved name spaces: ambiguous output is qualified; support
  1273 for hiding of names;
  1274 
  1275 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1276 XSYMBOL_HOME; no longer need to do manual configuration in most
  1277 situations;
  1278 
  1279 * system: compression of ML heaps images may now be controlled via -c
  1280 option of isabelle and isatool usedir (currently only observed by
  1281 Poly/ML);
  1282 
  1283 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1284 useful for remote X11);
  1285 
  1286 * system: provide TAGS file for Isabelle sources;
  1287 
  1288 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1289 order;
  1290 
  1291 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1292 timing flag supersedes proof_timing and Toplevel.trace;
  1293 
  1294 * ML: new combinators |>> and |>>> for incremental transformations
  1295 with secondary results (e.g. certain theory extensions):
  1296 
  1297 * ML: PureThy.add_defs gets additional argument to indicate potential
  1298 overloading (usually false);
  1299 
  1300 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1301 results;
  1302 
  1303 
  1304 
  1305 New in Isabelle99 (October 1999)
  1306 --------------------------------
  1307 
  1308 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1309 
  1310 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1311 are no longer simplified.  (This allows the simplifier to unfold recursive
  1312 functional programs.)  To restore the old behaviour, declare
  1313 
  1314     Delcongs [if_weak_cong];
  1315 
  1316 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1317 complement;
  1318 
  1319 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1320 
  1321 * HOL/datatype: mutual_induct_tac no longer exists --
  1322   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1323 
  1324 * HOL/typedef: fixed type inference for representing set; type
  1325 arguments now have to occur explicitly on the rhs as type constraints;
  1326 
  1327 * ZF: The con_defs part of an inductive definition may no longer refer
  1328 to constants declared in the same theory;
  1329 
  1330 * HOL, ZF: the function mk_cases, generated by the inductive
  1331 definition package, has lost an argument.  To simplify its result, it
  1332 uses the default simpset instead of a supplied list of theorems.
  1333 
  1334 * HOL/List: the constructors of type list are now Nil and Cons;
  1335 
  1336 * Simplifier: the type of the infix ML functions
  1337         setSSolver addSSolver setSolver addSolver
  1338 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1339 for packaging solvers. A solver is created via
  1340         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1341 where the string argument is only a comment.
  1342 
  1343 
  1344 *** Proof tools ***
  1345 
  1346 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1347 decision procedure for linear arithmetic. Currently it is used for
  1348 types `nat', `int', and `real' in HOL (see below); it can, should and
  1349 will be instantiated for other types and logics as well.
  1350 
  1351 * The simplifier now accepts rewrite rules with flexible heads, eg
  1352      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1353   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1354   matching.
  1355 
  1356 
  1357 *** General ***
  1358 
  1359 * New Isabelle/Isar subsystem provides an alternative to traditional
  1360 tactical theorem proving; together with the ProofGeneral/isar user
  1361 interface it offers an interactive environment for developing human
  1362 readable proof documents (Isar == Intelligible semi-automated
  1363 reasoning); for further information see isatool doc isar-ref,
  1364 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1365 
  1366 * improved and simplified presentation of theories: better HTML markup
  1367 (including colors), graph views in several sizes; isatool usedir now
  1368 provides a proper interface for user theories (via -P option); actual
  1369 document preparation based on (PDF)LaTeX is available as well (for
  1370 new-style theories only); see isatool doc system for more information;
  1371 
  1372 * native support for Proof General, both for classic Isabelle and
  1373 Isabelle/Isar;
  1374 
  1375 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1376 using the graph browser tool;
  1377 
  1378 * Isabelle manuals now also available as PDF;
  1379 
  1380 * theory loader rewritten from scratch (may not be fully
  1381 bug-compatible); old loadpath variable has been replaced by show_path,
  1382 add_path, del_path, reset_path functions; new operations such as
  1383 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1384 isatool doc ref);
  1385 
  1386 * improved isatool install: option -k creates KDE application icon,
  1387 option -p DIR installs standalone binaries;
  1388 
  1389 * added ML_PLATFORM setting (useful for cross-platform installations);
  1390 more robust handling of platform specific ML images for SML/NJ;
  1391 
  1392 * the settings environment is now statically scoped, i.e. it is never
  1393 created again in sub-processes invoked from isabelle, isatool, or
  1394 Isabelle;
  1395 
  1396 * path element specification '~~' refers to '$ISABELLE_HOME';
  1397 
  1398 * in locales, the "assumes" and "defines" parts may be omitted if
  1399 empty;
  1400 
  1401 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1402 long arrows);
  1403 
  1404 * new print_mode "HTML";
  1405 
  1406 * new flag show_tags controls display of tags of theorems (which are
  1407 basically just comments that may be attached by some tools);
  1408 
  1409 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1410 mode and goal output format:
  1411 
  1412 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1413 244c244
  1414 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1415 ---
  1416 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1417 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1418 181c181
  1419 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1420 ---
  1421 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1422 
  1423 * function bind_thms stores lists of theorems (cf. bind_thm);
  1424 
  1425 * new shorthand tactics ftac, eatac, datac, fatac;
  1426 
  1427 * qed (and friends) now accept "" as result name; in that case the
  1428 theorem is not stored, but proper checks and presentation of the
  1429 result still apply;
  1430 
  1431 * theorem database now also indexes constants "Trueprop", "all",
  1432 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1433 
  1434 
  1435 *** HOL ***
  1436 
  1437 ** HOL arithmetic **
  1438 
  1439 * There are now decision procedures for linear arithmetic over nat and
  1440 int:
  1441 
  1442 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1443 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1444 are treated as atomic; subformulae not involving type `nat' or `int'
  1445 are ignored; quantified subformulae are ignored unless they are
  1446 positive universal or negative existential. The tactic has to be
  1447 invoked by hand and can be a little bit slow. In particular, the
  1448 running time is exponential in the number of occurrences of `min' and
  1449 `max', and `-' on `nat'.
  1450 
  1451 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1452 (negated) (in)equalities among the premises and the conclusion into
  1453 account (i.e. no compound formulae) and does not know about `min' and
  1454 `max', and `-' on `nat'. It is fast and is used automatically by the
  1455 simplifier.
  1456 
  1457 NB: At the moment, these decision procedures do not cope with mixed
  1458 nat/int formulae where the two parts interact, such as `m < n ==>
  1459 int(m) < int(n)'.
  1460 
  1461 * HOL/Numeral provides a generic theory of numerals (encoded
  1462 efficiently as bit strings); setup for types nat/int/real is in place;
  1463 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1464 int, existing theories and proof scripts may require a few additional
  1465 type constraints;
  1466 
  1467 * integer division and remainder can now be performed on constant
  1468 arguments;
  1469 
  1470 * many properties of integer multiplication, division and remainder
  1471 are now available;
  1472 
  1473 * An interface to the Stanford Validity Checker (SVC) is available through the
  1474 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1475 are proved automatically.  SVC must be installed separately, and its results
  1476 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1477 invocation of the underlying oracle).  For SVC see
  1478   http://verify.stanford.edu/SVC
  1479 
  1480 * IsaMakefile: the HOL-Real target now builds an actual image;
  1481 
  1482 
  1483 ** HOL misc **
  1484 
  1485 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1486 (in Isabelle/Isar) -- by Gertrud Bauer;
  1487 
  1488 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1489 analysis for assembly languages with subtypes;
  1490 
  1491 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1492 -- avoids syntactic ambiguities and treats state, transition, and
  1493 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1494 changed syntax and (many) tactics;
  1495 
  1496 * HOL/inductive: Now also handles more general introduction rules such
  1497   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1498   theorems are now maintained within the theory (maintained via the
  1499   "mono" attribute);
  1500 
  1501 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1502   (using function types) such as
  1503 
  1504   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1505 
  1506 * HOL/record: record_simproc (part of the default simpset) takes care
  1507 of selectors applied to updated records; record_split_tac is no longer
  1508 part of the default claset; update_defs may now be removed from the
  1509 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1510 
  1511   claset_ref () := claset() addSWrapper record_split_wrapper;
  1512   Delsimprocs [record_simproc]
  1513 
  1514 * HOL/typedef: fixed type inference for representing set; type
  1515 arguments now have to occur explicitly on the rhs as type constraints;
  1516 
  1517 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1518 names rather than an ML expression;
  1519 
  1520 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1521 supplied later.  Program schemes can be defined, such as
  1522     "While B C s = (if B s then While B C (C s) else s)"
  1523 where the well-founded relation can be chosen after B and C have been given.
  1524 
  1525 * HOL/List: the constructors of type list are now Nil and Cons;
  1526 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1527 course, ML tools referring to List.list.op # etc. have to be adapted;
  1528 
  1529 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1530 disabled by default; run isabelle with option -m HOL to get back to
  1531 the original Gordon/HOL-style output;
  1532 
  1533 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1534 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1535 
  1536 * HOL basic syntax simplified (more orthogonal): all variants of
  1537 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1538 Eps operator is provided as well: "SOME x. P[x]";
  1539 
  1540 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1541 
  1542 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1543 thus available for user theories;
  1544 
  1545 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1546 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1547 time;
  1548 
  1549 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1550 several times and then mp;
  1551 
  1552 
  1553 *** LK ***
  1554 
  1555 * the notation <<...>> is now available as a notation for sequences of
  1556 formulas;
  1557 
  1558 * the simplifier is now installed
  1559 
  1560 * the axiom system has been generalized (thanks to Soren Heilmann)
  1561 
  1562 * the classical reasoner now has a default rule database
  1563 
  1564 
  1565 *** ZF ***
  1566 
  1567 * new primrec section allows primitive recursive functions to be given
  1568 directly (as in HOL) over datatypes and the natural numbers;
  1569 
  1570 * new tactics induct_tac and exhaust_tac for induction (or case
  1571 analysis) over datatypes and the natural numbers;
  1572 
  1573 * the datatype declaration of type T now defines the recursor T_rec;
  1574 
  1575 * simplification automatically does freeness reasoning for datatype
  1576 constructors;
  1577 
  1578 * automatic type-inference, with AddTCs command to insert new
  1579 type-checking rules;
  1580 
  1581 * datatype introduction rules are now added as Safe Introduction rules
  1582 to the claset;
  1583 
  1584 * the syntax "if P then x else y" is now available in addition to
  1585 if(P,x,y);
  1586 
  1587 
  1588 *** Internal programming interfaces ***
  1589 
  1590 * tuned simplifier trace output; new flag debug_simp;
  1591 
  1592 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1593 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1594 
  1595 * AxClass.axclass_tac lost the theory argument;
  1596 
  1597 * tuned current_goals_markers semantics: begin / end goal avoids
  1598 printing empty lines;
  1599 
  1600 * removed prs and prs_fn hook, which was broken because it did not
  1601 include \n in its semantics, forcing writeln to add one
  1602 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1603 string -> unit if you really want to output text without newline;
  1604 
  1605 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1606 plain output, interface builders may have to enable 'isabelle_font'
  1607 mode to get Isabelle font glyphs as before;
  1608 
  1609 * refined token_translation interface; INCOMPATIBILITY: output length
  1610 now of type real instead of int;
  1611 
  1612 * theory loader actions may be traced via new ThyInfo.add_hook
  1613 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1614 your own database of information attached to *whole* theories -- as
  1615 opposed to intra-theory data slots offered via TheoryDataFun;
  1616 
  1617 * proper handling of dangling sort hypotheses (at last!);
  1618 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1619 extra sort hypotheses that can be witnessed from the type signature;
  1620 the force_strip_shyps flag is gone, any remaining shyps are simply
  1621 left in the theorem (with a warning issued by strip_shyps_warning);
  1622 
  1623 
  1624 
  1625 New in Isabelle98-1 (October 1998)
  1626 ----------------------------------
  1627 
  1628 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1629 
  1630 * several changes of automated proof tools;
  1631 
  1632 * HOL: major changes to the inductive and datatype packages, including
  1633 some minor incompatibilities of theory syntax;
  1634 
  1635 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1636 called `inj_on';
  1637 
  1638 * HOL: removed duplicate thms in Arith:
  1639   less_imp_add_less  should be replaced by  trans_less_add1
  1640   le_imp_add_le      should be replaced by  trans_le_add1
  1641 
  1642 * HOL: unary minus is now overloaded (new type constraints may be
  1643 required);
  1644 
  1645 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1646 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1647 now taken as an integer constant.
  1648 
  1649 * Pure: ML function 'theory_of' renamed to 'theory';
  1650 
  1651 
  1652 *** Proof tools ***
  1653 
  1654 * Simplifier:
  1655   1. Asm_full_simp_tac is now more aggressive.
  1656      1. It will sometimes reorient premises if that increases their power to
  1657         simplify.
  1658      2. It does no longer proceed strictly from left to right but may also
  1659         rotate premises to achieve further simplification.
  1660      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1661      old Asm_full_simp_tac in that it does not rotate premises.
  1662   2. The simplifier now knows a little bit about nat-arithmetic.
  1663 
  1664 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1665 allows for selected deletion of wrappers, by introduction of names for
  1666 wrapper functionals.  This implies that addbefore, addSbefore,
  1667 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1668 and that adding two tactics with the same name overwrites the first
  1669 one (emitting a warning).
  1670   type wrapper = (int -> tactic) -> (int -> tactic)
  1671   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1672   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1673   delWrapper, delSWrapper: claset *  string            -> claset
  1674   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1675 
  1676 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1677 semantics; addbefore now affects only the unsafe part of step_tac
  1678 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1679 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1680 by Force_tac;
  1681 
  1682 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1683 compWrapper; added safe wrapper (and access functions for it);
  1684 
  1685 * HOL/split_all_tac is now much faster and fails if there is nothing
  1686 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1687 and the names of the automatically generated variables have changed.
  1688 split_all_tac has moved within claset() from unsafe wrappers to safe
  1689 wrappers, which means that !!-bound variables are split much more
  1690 aggressively, and safe_tac and clarify_tac now split such variables.
  1691 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1692 Note: the same holds for record_split_tac, which does the job of
  1693 split_all_tac for record fields.
  1694 
  1695 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1696 permanently to the default simpset using Addsplits just like
  1697 Addsimps. They can be removed via Delsplits just like
  1698 Delsimps. Lower-case versions are also available.
  1699 
  1700 * HOL/Simplifier: The rule split_if is now part of the default
  1701 simpset. This means that the simplifier will eliminate all occurrences
  1702 of if-then-else in the conclusion of a goal. To prevent this, you can
  1703 either remove split_if completely from the default simpset by
  1704 `Delsplits [split_if]' or remove it in a specific call of the
  1705 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1706 other case splitting rules to/from the default simpset: every datatype
  1707 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1708 t is the name of the datatype).
  1709 
  1710 * Classical reasoner / Simplifier combination: new force_tac (and
  1711 derivatives Force_tac, force) combines rewriting and classical
  1712 reasoning (and whatever other tools) similarly to auto_tac, but is
  1713 aimed to solve the given subgoal completely.
  1714 
  1715 
  1716 *** General ***
  1717 
  1718 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1719 and `goalw': the theory is no longer needed as an explicit argument -
  1720 the current theory context is used; assumptions are no longer returned
  1721 at the ML-level unless one of them starts with ==> or !!; it is
  1722 recommended to convert to these new commands using isatool fixgoal
  1723 (backup your sources first!);
  1724 
  1725 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1726 the current theory context, and 'theory' to lookup stored theories;
  1727 
  1728 * new theory section 'locale' for declaring constants, assumptions and
  1729 definitions that have local scope;
  1730 
  1731 * new theory section 'nonterminals' for purely syntactic types;
  1732 
  1733 * new theory section 'setup' for generic ML setup functions
  1734 (e.g. package initialization);
  1735 
  1736 * the distribution now includes Isabelle icons: see
  1737 lib/logo/isabelle-{small,tiny}.xpm;
  1738 
  1739 * isatool install - install binaries with absolute references to
  1740 ISABELLE_HOME/bin;
  1741 
  1742 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1743 
  1744 * print mode 'emacs' reserved for Isamode;
  1745 
  1746 * support multiple print (ast) translations per constant name;
  1747 
  1748 * theorems involving oracles are now printed with a suffixed [!];
  1749 
  1750 
  1751 *** HOL ***
  1752 
  1753 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1754 
  1755 * HOL/inductive package reorganized and improved: now supports mutual
  1756 definitions such as
  1757 
  1758   inductive EVEN ODD
  1759     intrs
  1760       null "0 : EVEN"
  1761       oddI "n : EVEN ==> Suc n : ODD"
  1762       evenI "n : ODD ==> Suc n : EVEN"
  1763 
  1764 new theorem list "elims" contains an elimination rule for each of the
  1765 recursive sets; inductive definitions now handle disjunctive premises
  1766 correctly (also ZF);
  1767 
  1768 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1769 "mutual_induct" no longer exists - the induction rule is always
  1770 contained in "induct";
  1771 
  1772 
  1773 * HOL/datatype package re-implemented and greatly improved: now
  1774 supports mutually recursive datatypes such as
  1775 
  1776   datatype
  1777     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1778             | SUM ('a aexp) ('a aexp)
  1779             | DIFF ('a aexp) ('a aexp)
  1780             | NUM 'a
  1781   and
  1782     'a bexp = LESS ('a aexp) ('a aexp)
  1783             | AND ('a bexp) ('a bexp)
  1784             | OR ('a bexp) ('a bexp)
  1785 
  1786 as well as indirectly recursive datatypes such as
  1787 
  1788   datatype
  1789     ('a, 'b) term = Var 'a
  1790                   | App 'b ((('a, 'b) term) list)
  1791 
  1792 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1793 induction on mutually / indirectly recursive datatypes.
  1794 
  1795 Primrec equations are now stored in theory and can be accessed via
  1796 <function_name>.simps.
  1797 
  1798 INCOMPATIBILITIES:
  1799 
  1800   - Theories using datatypes must now have theory Datatype as an
  1801     ancestor.
  1802   - The specific <typename>.induct_tac no longer exists - use the
  1803     generic induct_tac instead.
  1804   - natE has been renamed to nat.exhaust - use exhaust_tac
  1805     instead of res_inst_tac ... natE. Note that the variable
  1806     names in nat.exhaust differ from the names in natE, this
  1807     may cause some "fragile" proofs to fail.
  1808   - The theorems split_<typename>_case and split_<typename>_case_asm
  1809     have been renamed to <typename>.split and <typename>.split_asm.
  1810   - Since default sorts of type variables are now handled correctly,
  1811     some datatype definitions may have to be annotated with explicit
  1812     sort constraints.
  1813   - Primrec definitions no longer require function name and type
  1814     of recursive argument.
  1815 
  1816 Consider using isatool fixdatatype to adapt your theories and proof
  1817 scripts to the new package (backup your sources first!).
  1818 
  1819 
  1820 * HOL/record package: considerably improved implementation; now
  1821 includes concrete syntax for record types, terms, updates; theorems
  1822 for surjective pairing and splitting !!-bound record variables; proof
  1823 support is as follows:
  1824 
  1825   1) standard conversions (selectors or updates applied to record
  1826 constructor terms) are part of the standard simpset;
  1827 
  1828   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1829 made part of standard simpset and claset via addIffs;
  1830 
  1831   3) a tactic for record field splitting (record_split_tac) is part of
  1832 the standard claset (addSWrapper);
  1833 
  1834 To get a better idea about these rules you may retrieve them via
  1835 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1836 the name of your record type.
  1837 
  1838 The split tactic 3) conceptually simplifies by the following rule:
  1839 
  1840   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1841 
  1842 Thus any record variable that is bound by meta-all will automatically
  1843 blow up into some record constructor term, consequently the
  1844 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1845 solve record problems automatically.
  1846 
  1847 
  1848 * reorganized the main HOL image: HOL/Integ and String loaded by
  1849 default; theory Main includes everything;
  1850 
  1851 * automatic simplification of integer sums and comparisons, using cancellation;
  1852 
  1853 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1854 
  1855 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1856 
  1857 * many new identities for unions, intersections, set difference, etc.;
  1858 
  1859 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1860 called split_if, split_split, split_sum_case and split_nat_case (to go
  1861 with add/delsplits);
  1862 
  1863 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1864 (?x::unit) = (); this is made part of the default simpset, which COULD
  1865 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1866 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1867 unit_abs_eta_conv is added in order to counter the effect of
  1868 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1869 %u.f();
  1870 
  1871 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1872 makes more sense);
  1873 
  1874 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1875   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1876   disjointness reasoning but breaking a few old proofs.
  1877 
  1878 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1879 to 'converse' from 'inverse' (for compatibility with ZF and some
  1880 literature);
  1881 
  1882 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1883 the well-founded relation;
  1884 
  1885 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1886     Compl A.  The "Compl" syntax remains available as input syntax for this
  1887     release ONLY.
  1888 
  1889 * HOL/Update: new theory of function updates:
  1890     f(a:=b) == %x. if x=a then b else f x
  1891 may also be iterated as in f(a:=b,c:=d,...);
  1892 
  1893 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1894 
  1895 * HOL/List:
  1896   - new function list_update written xs[i:=v] that updates the i-th
  1897     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1898   - new function `upt' written [i..j(] which generates the list
  1899     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1900     bound write [i..j], which is a shorthand for [i..j+1(].
  1901   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1902 
  1903 * HOL/Arith:
  1904   - removed 'pred' (predecessor) function;
  1905   - generalized some theorems about n-1;
  1906   - many new laws about "div" and "mod";
  1907   - new laws about greatest common divisors (see theory ex/Primes);
  1908 
  1909 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1910 instead of "inverse";
  1911 
  1912 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1913   of the multiset ordering;
  1914 
  1915 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1916   (not included by default);
  1917 
  1918 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1919 
  1920 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1921   programs, i.e. different program variables may have different types.
  1922 
  1923 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1924   [previously, this check worked only if the rewrite rule was unconditional]
  1925   Now rew can involve either definitions or equalities (either == or =).
  1926 
  1927 
  1928 *** ZF ***
  1929 
  1930 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1931   only the theorems proved on ZF.ML;
  1932 
  1933 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1934   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1935   disjointness reasoning but breaking a few old proofs.
  1936 
  1937 * ZF/Update: new theory of function updates
  1938     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1939   may also be iterated as in f(a:=b,c:=d,...);
  1940 
  1941 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1942 
  1943 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1944   [previously, this check worked only if the rewrite rule was unconditional]
  1945   Now rew can involve either definitions or equalities (either == or =).
  1946 
  1947 * case_tac provided for compatibility with HOL
  1948     (like the old excluded_middle_tac, but with subgoals swapped)
  1949 
  1950 
  1951 *** Internal programming interfaces ***
  1952 
  1953 * Pure: several new basic modules made available for general use, see
  1954 also src/Pure/README;
  1955 
  1956 * improved the theory data mechanism to support encapsulation (data
  1957 kind name replaced by private Object.kind, acting as authorization
  1958 key); new type-safe user interface via functor TheoryDataFun; generic
  1959 print_data function becomes basically useless;
  1960 
  1961 * removed global_names compatibility flag -- all theory declarations
  1962 are qualified by default;
  1963 
  1964 * module Pure/Syntax now offers quote / antiquote translation
  1965 functions (useful for Hoare logic etc. with implicit dependencies);
  1966 see HOL/ex/Antiquote for an example use;
  1967 
  1968 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1969 cterm -> thm;
  1970 
  1971 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1972 subgoal;
  1973 
  1974 * Display.print_goals function moved to Locale.print_goals;
  1975 
  1976 * standard print function for goals supports current_goals_markers
  1977 variable for marking begin of proof, end of proof, start of goal; the
  1978 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1979 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1980 for example;
  1981 
  1982 
  1983 
  1984 New in Isabelle98 (January 1998)
  1985 --------------------------------
  1986 
  1987 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1988 
  1989 * changed lexical syntax of terms / types: dots made part of long
  1990 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1991 
  1992 * simpset (and claset) reference variable replaced by functions
  1993 simpset / simpset_ref;
  1994 
  1995 * no longer supports theory aliases (via merge) and non-trivial
  1996 implicit merge of thms' signatures;
  1997 
  1998 * most internal names of constants changed due to qualified names;
  1999 
  2000 * changed Pure/Sequence interface (see Pure/seq.ML);
  2001 
  2002 
  2003 *** General Changes ***
  2004 
  2005 * hierachically structured name spaces (for consts, types, axms, thms
  2006 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2007 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2008 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2009 long_names for fully qualified output names; NOTE: ML programs
  2010 (special tactics, packages etc.) referring to internal names may have
  2011 to be adapted to cope with fully qualified names; in case of severe
  2012 backward campatibility problems try setting 'global_names' at compile
  2013 time to have enrything declared within a flat name space; one may also
  2014 fine tune name declarations in theories via the 'global' and 'local'
  2015 section;
  2016 
  2017 * reimplemented the implicit simpset and claset using the new anytype
  2018 data filed in signatures; references simpset:simpset ref etc. are
  2019 replaced by functions simpset:unit->simpset and
  2020 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2021 to patch your ML files accordingly;
  2022 
  2023 * HTML output now includes theory graph data for display with Java
  2024 applet or isatool browser; data generated automatically via isatool
  2025 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2026 
  2027 * defs may now be conditional; improved rewrite_goals_tac to handle
  2028 conditional equations;
  2029 
  2030 * defs now admits additional type arguments, using TYPE('a) syntax;
  2031 
  2032 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2033 creates a new theory node; implicit merge of thms' signatures is
  2034 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2035 transfer:theory->thm->thm in (rare) cases;
  2036 
  2037 * improved handling of draft signatures / theories; draft thms (and
  2038 ctyps, cterms) are automatically promoted to real ones;
  2039 
  2040 * slightly changed interfaces for oracles: admit many per theory, named
  2041 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2042 
  2043 * print_goals: optional output of const types (set show_consts and
  2044 show_types);
  2045 
  2046 * improved output of warnings (###) and errors (***);
  2047 
  2048 * subgoal_tac displays a warning if the new subgoal has type variables;
  2049 
  2050 * removed old README and Makefiles;
  2051 
  2052 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2053 
  2054 * removed obsolete init_pps and init_database;
  2055 
  2056 * deleted the obsolete tactical STATE, which was declared by
  2057     fun STATE tacfun st = tacfun st st;
  2058 
  2059 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2060 (which abbreviates $HOME);
  2061 
  2062 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2063 use isatool fixseq to adapt your ML programs (this works for fully
  2064 qualified references to the Sequence structure only!);
  2065 
  2066 * use_thy no longer requires writable current directory; it always
  2067 reloads .ML *and* .thy file, if either one is out of date;
  2068 
  2069 
  2070 *** Classical Reasoner ***
  2071 
  2072 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2073 tactics that use classical reasoning to simplify a subgoal without
  2074 splitting it into several subgoals;
  2075 
  2076 * Safe_tac: like safe_tac but uses the default claset;
  2077 
  2078 
  2079 *** Simplifier ***
  2080 
  2081 * added simplification meta rules:
  2082     (asm_)(full_)simplify: simpset -> thm -> thm;
  2083 
  2084 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2085 logics (again);
  2086 
  2087 * added prems argument to simplification procedures;
  2088 
  2089 * HOL, FOL, ZF: added infix function `addsplits':
  2090   instead of `<simpset> setloop (split_tac <thms>)'
  2091   you can simply write `<simpset> addsplits <thms>'
  2092 
  2093 
  2094 *** Syntax ***
  2095 
  2096 * TYPE('a) syntax for type reflection terms;
  2097 
  2098 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2099 
  2100 * pretty printer: changed order of mixfix annotation preference (again!);
  2101 
  2102 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2103 
  2104 
  2105 *** HOL ***
  2106 
  2107 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2108   with `addloop' of the simplifier to faciliate case splitting in premises.
  2109 
  2110 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2111 
  2112 * HOL/Auth: new protocol proofs including some for the Internet
  2113   protocol TLS;
  2114 
  2115 * HOL/Map: new theory of `maps' a la VDM;
  2116 
  2117 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2118 cancelling out common nat summands from =, <, <= (in)equalities, or
  2119 differences; simplification procedures nat_cancel_factor for
  2120 cancelling common factor from =, <, <= (in)equalities over natural
  2121 sums; nat_cancel contains both kinds of procedures, it is installed by
  2122 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2123 
  2124 * HOL/simplifier: terms of the form
  2125   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2126   are rewritten to
  2127   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2128   and those of the form
  2129   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2130   are rewritten to
  2131   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2132 
  2133 * HOL/datatype
  2134   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2135 
  2136   P(t_case f1 ... fn x) =
  2137      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2138         ...
  2139        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2140      )
  2141 
  2142   and a theorem `split_t_case_asm' of the form
  2143 
  2144   P(t_case f1 ... fn x) =
  2145     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2146         ...
  2147        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2148      )
  2149   which can be added to a simpset via `addsplits'. The existing theorems
  2150   expand_list_case and expand_option_case have been renamed to
  2151   split_list_case and split_option_case.
  2152 
  2153 * HOL/Arithmetic:
  2154   - `pred n' is automatically converted to `n-1'.
  2155     Users are strongly encouraged not to use `pred' any longer,
  2156     because it will disappear altogether at some point.
  2157   - Users are strongly encouraged to write "0 < n" rather than
  2158     "n ~= 0". Theorems and proof tools have been modified towards this
  2159     `standard'.
  2160 
  2161 * HOL/Lists:
  2162   the function "set_of_list" has been renamed "set" (and its theorems too);
  2163   the function "nth" now takes its arguments in the reverse order and
  2164   has acquired the infix notation "!" as in "xs!n".
  2165 
  2166 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2167 
  2168 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2169   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2170 
  2171 * HOL/record: extensible records with schematic structural subtyping
  2172 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2173 still lacks various theorems and concrete record syntax;
  2174 
  2175 
  2176 *** HOLCF ***
  2177 
  2178 * removed "axioms" and "generated by" sections;
  2179 
  2180 * replaced "ops" section by extended "consts" section, which is capable of
  2181   handling the continuous function space "->" directly;
  2182 
  2183 * domain package:
  2184   . proves theorems immediately and stores them in the theory,
  2185   . creates hierachical name space,
  2186   . now uses normal mixfix annotations (instead of cinfix...),
  2187   . minor changes to some names and values (for consistency),
  2188   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2189   . separator between mutual domain defs: changed "," to "and",
  2190   . improved handling of sort constraints;  now they have to
  2191     appear on the left-hand side of the equations only;
  2192 
  2193 * fixed LAM <x,y,zs>.b syntax;
  2194 
  2195 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2196 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2197 
  2198 
  2199 *** FOL and ZF ***
  2200 
  2201 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2202   with `addloop' of the simplifier to faciliate case splitting in premises.
  2203 
  2204 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2205 in HOL, they strip ALL and --> from proved theorems;
  2206 
  2207 
  2208 
  2209 New in Isabelle94-8 (May 1997)
  2210 ------------------------------
  2211 
  2212 *** General Changes ***
  2213 
  2214 * new utilities to build / run / maintain Isabelle etc. (in parts
  2215 still somewhat experimental); old Makefiles etc. still functional;
  2216 
  2217 * new 'Isabelle System Manual';
  2218 
  2219 * INSTALL text, together with ./configure and ./build scripts;
  2220 
  2221 * reimplemented type inference for greater efficiency, better error
  2222 messages and clean internal interface;
  2223 
  2224 * prlim command for dealing with lots of subgoals (an easier way of
  2225 setting goals_limit);
  2226 
  2227 
  2228 *** Syntax ***
  2229 
  2230 * supports alternative (named) syntax tables (parser and pretty
  2231 printer); internal interface is provided by add_modesyntax(_i);
  2232 
  2233 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2234 be used in conjunction with the Isabelle symbol font; uses the
  2235 "symbols" syntax table;
  2236 
  2237 * added token_translation interface (may translate name tokens in
  2238 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2239 the current print_mode); IMPORTANT: user print translation functions
  2240 are responsible for marking newly introduced bounds
  2241 (Syntax.mark_boundT);
  2242 
  2243 * token translations for modes "xterm" and "xterm_color" that display
  2244 names in bold, underline etc. or colors (which requires a color
  2245 version of xterm);
  2246 
  2247 * infixes may now be declared with names independent of their syntax;
  2248 
  2249 * added typed_print_translation (like print_translation, but may
  2250 access type of constant);
  2251 
  2252 
  2253 *** Classical Reasoner ***
  2254 
  2255 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2256 some limitations.  Blast_tac...
  2257   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2258   + ignores elimination rules that don't have the correct format
  2259         (the conclusion MUST be a formula variable)
  2260   + ignores types, which can make HOL proofs fail
  2261   + rules must not require higher-order unification, e.g. apply_type in ZF
  2262     [message "Function Var's argument not a bound variable" relates to this]
  2263   + its proof strategy is more general but can actually be slower
  2264 
  2265 * substitution with equality assumptions no longer permutes other
  2266 assumptions;
  2267 
  2268 * minor changes in semantics of addafter (now called addaltern); renamed
  2269 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2270 (and access functions for it);
  2271 
  2272 * improved combination of classical reasoner and simplifier:
  2273   + functions for handling clasimpsets
  2274   + improvement of addss: now the simplifier is called _after_ the
  2275     safe steps.
  2276   + safe variant of addss called addSss: uses safe simplifications
  2277     _during_ the safe steps. It is more complete as it allows multiple
  2278     instantiations of unknowns (e.g. with slow_tac).
  2279 
  2280 *** Simplifier ***
  2281 
  2282 * added interface for simplification procedures (functions that
  2283 produce *proven* rewrite rules on the fly, depending on current
  2284 redex);
  2285 
  2286 * ordering on terms as parameter (used for ordered rewriting);
  2287 
  2288 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2289 
  2290 * the solver is now split into a safe and an unsafe part.
  2291 This should be invisible for the normal user, except that the
  2292 functions setsolver and addsolver have been renamed to setSolver and
  2293 addSolver; added safe_asm_full_simp_tac;
  2294 
  2295 
  2296 *** HOL ***
  2297 
  2298 * a generic induction tactic `induct_tac' which works for all datatypes and
  2299 also for type `nat';
  2300 
  2301 * a generic case distinction tactic `exhaust_tac' which works for all
  2302 datatypes and also for type `nat';
  2303 
  2304 * each datatype comes with a function `size';
  2305 
  2306 * patterns in case expressions allow tuple patterns as arguments to
  2307 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2308 
  2309 * primrec now also works with type nat;
  2310 
  2311 * recdef: a new declaration form, allows general recursive functions to be
  2312 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2313 
  2314 * the constant for negation has been renamed from "not" to "Not" to
  2315 harmonize with FOL, ZF, LK, etc.;
  2316 
  2317 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2318 infinite lists;
  2319 
  2320 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2321 
  2322 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2323 problems in commutative rings, using axiomatic type classes for + and *;
  2324 
  2325 * more examples in HOL/MiniML and HOL/Auth;
  2326 
  2327 * more default rewrite rules for quantifiers, union/intersection;
  2328 
  2329 * a new constant `arbitrary == @x.False';
  2330 
  2331 * HOLCF/IOA replaces old HOL/IOA;
  2332 
  2333 * HOLCF changes: derived all rules and arities
  2334   + axiomatic type classes instead of classes
  2335   + typedef instead of faking type definitions
  2336   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2337   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2338   + eliminated the types void, one, tr
  2339   + use unit lift and bool lift (with translations) instead of one and tr
  2340   + eliminated blift from Lift3.thy (use Def instead of blift)
  2341   all eliminated rules are derived as theorems --> no visible changes ;
  2342 
  2343 
  2344 *** ZF ***
  2345 
  2346 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2347 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2348 as ZF_cs addSIs [equalityI];
  2349 
  2350 
  2351 
  2352 New in Isabelle94-7 (November 96)
  2353 ---------------------------------
  2354 
  2355 * allowing negative levels (as offsets) in prlev and choplev;
  2356 
  2357 * super-linear speedup for large simplifications;
  2358 
  2359 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2360 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2361 FAIL); can suppress it using the command Delsimps (ex_simps @
  2362 all_simps); De Morgan laws are also now included, by default;
  2363 
  2364 * improved printing of ==>  :  ~:
  2365 
  2366 * new object-logic "Sequents" adds linear logic, while replacing LK
  2367 and Modal (thanks to Sara Kalvala);
  2368 
  2369 * HOL/Auth: correctness proofs for authentication protocols;
  2370 
  2371 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2372 examples on HOL/Auth);
  2373 
  2374 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2375 the rewriter and classical reasoner simultaneously;
  2376 
  2377 * function uresult no longer returns theorems in "standard" format;
  2378 regain previous version by: val uresult = standard o uresult;
  2379 
  2380 
  2381 
  2382 New in Isabelle94-6
  2383 -------------------
  2384 
  2385 * oracles -- these establish an interface between Isabelle and trusted
  2386 external reasoners, which may deliver results as theorems;
  2387 
  2388 * proof objects (in particular record all uses of oracles);
  2389 
  2390 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2391 
  2392 * "constdefs" section in theory files;
  2393 
  2394 * "primrec" section (HOL) no longer requires names;
  2395 
  2396 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2397 
  2398 
  2399 
  2400 New in Isabelle94-5
  2401 -------------------
  2402 
  2403 * reduced space requirements;
  2404 
  2405 * automatic HTML generation from theories;
  2406 
  2407 * theory files no longer require "..." (quotes) around most types;
  2408 
  2409 * new examples, including two proofs of the Church-Rosser theorem;
  2410 
  2411 * non-curried (1994) version of HOL is no longer distributed;
  2412 
  2413 
  2414 
  2415 New in Isabelle94-4
  2416 -------------------
  2417 
  2418 * greatly reduced space requirements;
  2419 
  2420 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2421 
  2422 * searchable theorem database (see the section "Retrieving theorems" on
  2423 page 8 of the Reference Manual);
  2424 
  2425 * new examples, including Grabczewski's monumental case study of the
  2426 Axiom of Choice;
  2427 
  2428 * The previous version of HOL renamed to Old_HOL;
  2429 
  2430 * The new version of HOL (previously called CHOL) uses a curried syntax
  2431 for functions.  Application looks like f a b instead of f(a,b);
  2432 
  2433 * Mutually recursive inductive definitions finally work in HOL;
  2434 
  2435 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2436 translates to the operator "split";
  2437 
  2438 
  2439 
  2440 New in Isabelle94-3
  2441 -------------------
  2442 
  2443 * new infix operator, addss, allowing the classical reasoner to
  2444 perform simplification at each step of its search.  Example:
  2445         fast_tac (cs addss ss)
  2446 
  2447 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2448 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2449 look like (a,b) instead of <a,b>;
  2450 
  2451 * PLEASE NOTE: CHOL will eventually replace HOL!
  2452 
  2453 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2454 It translates to the operator "split".  A new theory of integers is available;
  2455 
  2456 * In ZF, integer numerals now denote two's-complement binary integers.
  2457 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2458 
  2459 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2460 of the Axiom of Choice;
  2461 
  2462 
  2463 
  2464 New in Isabelle94-2
  2465 -------------------
  2466 
  2467 * Significantly faster resolution;
  2468 
  2469 * the different sections in a .thy file can now be mixed and repeated
  2470 freely;
  2471 
  2472 * Database of theorems for FOL, HOL and ZF.  New
  2473 commands including qed, qed_goal and bind_thm store theorems in the database.
  2474 
  2475 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2476 a given theory (thms_of), or find out what theory a theorem was proved in
  2477 (theory_of_thm);
  2478 
  2479 * Bugs fixed in the inductive definition and datatype packages;
  2480 
  2481 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2482 and HOL_dup_cs obsolete;
  2483 
  2484 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2485 have been removed;
  2486 
  2487 * Simpler definition of function space in ZF;
  2488 
  2489 * new results about cardinal and ordinal arithmetic in ZF;
  2490 
  2491 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2492 types;
  2493 
  2494 
  2495 $Id$