NEWS
author ballarin
Wed Dec 10 14:27:50 2003 +0100 (2003-12-10)
changeset 14285 92ed032e83a1
parent 14283 516358ca7b42
child 14333 14f29eb097a3
permissions -rw-r--r--
Isar: where attribute supports instantiation of type vars.
     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 * Attributes "where" and "of":
    45   - Now take type variables of instantiated theorem into account when reading
    46     the instantiation string.  This fixes a bug that caused instantiated
    47     theorems to have too special types in some circumstances.
    48   - "where" permits explicit instantiations of type variables.
    49 
    50 * Calculation commands "moreover" and "also":
    51   Do not reset facts ("this") any more.
    52 
    53 * Locales:
    54   - Goal statements involving the context element "includes" no longer
    55     generate theorems with internal delta predicates (those ending on
    56     "_axioms") in the premise.
    57     Resolve particular premise with <locale>.intro to obtain old form.
    58   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
    59     specification and "includes" elements in goal statement.
    60   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
    61     [intro?] and [elim?] (respectively) by default.
    62 
    63 * HOL: Tactic emulation methods induct_tac and case_tac understand static
    64   (Isar) contexts.
    65 
    66 *** HOL ***
    67 
    68 * Records:
    69   - Record types are now by default printed with their type abbreviation
    70     instead of the list of all field types. This can be configured via
    71     the reference "print_record_type_abbr".
    72   - Simproc "record_upd_simproc" for simplification of multiple updates added 
    73     (not enabled by default).
    74   - Tactic "record_split_simp_tac" to split and simplify records added.
    75  
    76 * 'specification' command added, allowing for definition by
    77   specification.  There is also an 'ax_specification' command that
    78   introduces the new constants axiomatically.
    79 
    80 * SET-Protocol: formalization and verification of the SET protocol suite;
    81 
    82 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
    83  defintions, thanks to Sava Krsti\'{c} and John Matthews.
    84 
    85 New in Isabelle2003 (May 2003)
    86 --------------------------------
    87 
    88 *** General ***
    89 
    90 * Provers/simplifier:
    91 
    92   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
    93     Assumptions are now subject to complete mutual simplification,
    94     not just from left to right. The simplifier now preserves
    95     the order of assumptions.
    96 
    97     Potential INCOMPATIBILITY:
    98 
    99     -- simp sometimes diverges where the old version did
   100        not, e.g. invoking simp on the goal
   101 
   102         [| P (f x); y = x; f x = f y |] ==> Q
   103 
   104        now gives rise to the infinite reduction sequence
   105 
   106         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   107 
   108        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   109        kind of problem.
   110 
   111     -- Tactics combining classical reasoner and simplification (such as auto)
   112        are also affected by this change, because many of them rely on
   113        simp. They may sometimes diverge as well or yield a different numbers
   114        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   115        in case of problems. Sometimes subsequent calls to the classical
   116        reasoner will fail because a preceeding call to the simplifier too
   117        eagerly simplified the goal, e.g. deleted redundant premises.
   118 
   119   - The simplifier trace now shows the names of the applied rewrite rules
   120 
   121   - You can limit the number of recursive invocations of the simplifier
   122     during conditional rewriting (where the simplifie tries to solve the
   123     conditions before applying the rewrite rule):
   124     ML "simp_depth_limit := n"
   125     where n is an integer. Thus you can force termination where previously
   126     the simplifier would diverge.
   127 
   128   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   129 
   130   - No longer aborts on failed congruence proof.  Instead, the
   131     congruence is ignored.
   132 
   133 * Pure: New generic framework for extracting programs from constructive
   134   proofs. See HOL/Extraction.thy for an example instantiation, as well
   135   as HOL/Extraction for some case studies.
   136 
   137 * Pure: The main goal of the proof state is no longer shown by default, only
   138 the subgoals. This behaviour is controlled by a new flag.
   139    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   140 (ML: Proof.show_main_goal).
   141 
   142 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   143 rules whose conclusion matches subgoal 1:
   144       PG menu: Isabelle/Isar -> Show me -> matching rules
   145 The rules are ordered by how closely they match the subgoal.
   146 In particular, rules that solve a subgoal outright are displayed first
   147 (or rather last, the way they are printed).
   148 (ML: ProofGeneral.print_intros())
   149 
   150 * Pure: New flag trace_unify_fail causes unification to print
   151 diagnostic information (PG: in trace buffer) when it fails. This is
   152 useful for figuring out why single step proofs like rule, erule or
   153 assumption failed.
   154 
   155 * Pure: Locale specifications now produce predicate definitions
   156 according to the body of text (covering assumptions modulo local
   157 definitions); predicate "loc_axioms" covers newly introduced text,
   158 while "loc" is cumulative wrt. all included locale expressions; the
   159 latter view is presented only on export into the global theory
   160 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   161 on the old view without predicates;
   162 
   163 * Pure: predefined locales "var" and "struct" are useful for sharing
   164 parameters (as in CASL, for example); just specify something like
   165 ``var x + var y + struct M'' as import;
   166 
   167 * Pure: improved thms_containing: proper indexing of facts instead of
   168 raw theorems; check validity of results wrt. current name space;
   169 include local facts of proof configuration (also covers active
   170 locales), cover fixed variables in index; may use "_" in term
   171 specification; an optional limit for the number of printed facts may
   172 be given (the default is 40);
   173 
   174 * Pure: disallow duplicate fact bindings within new-style theory files
   175 (batch-mode only);
   176 
   177 * Provers: improved induct method: assumptions introduced by case
   178 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   179 the goal statement); "foo" still refers to all facts collectively;
   180 
   181 * Provers: the function blast.overloaded has been removed: all constants
   182 are regarded as potentially overloaded, which improves robustness in exchange
   183 for slight decrease in efficiency;
   184 
   185 * Provers/linorder: New generic prover for transitivity reasoning over
   186 linear orders.  Note: this prover is not efficient!
   187 
   188 * Isar: preview of problems to finish 'show' now produce an error
   189 rather than just a warning (in interactive mode);
   190 
   191 
   192 *** HOL ***
   193 
   194 * arith(_tac)
   195 
   196  - Produces a counter example if it cannot prove a goal.
   197    Note that the counter example may be spurious if the goal is not a formula
   198    of quantifier-free linear arithmetic.
   199    In ProofGeneral the counter example appears in the trace buffer.
   200 
   201  - Knows about div k and mod k where k is a numeral of type nat or int.
   202 
   203  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   204    linear arithmetic fails. This takes account of quantifiers and divisibility.
   205    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   206 
   207 * simp's arithmetic capabilities have been enhanced a bit: it now
   208 takes ~= in premises into account (by performing a case split);
   209 
   210 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   211 are distributed over a sum of terms;
   212 
   213 * New tactic "trans_tac" and method "trans" instantiate
   214 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   215 "<=", "<" and "="). 
   216 
   217 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   218 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   219 
   220 * 'typedef' command has new option "open" to suppress the set
   221 definition;
   222 
   223 * functions Min and Max on finite sets have been introduced (theory
   224 Finite_Set);
   225 
   226 * attribute [symmetric] now works for relations as well; it turns
   227 (x,y) : R^-1 into (y,x) : R, and vice versa;
   228 
   229 * induct over a !!-quantified statement (say !!x1..xn):
   230   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   231 
   232 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   233 %x. None. Warning: empty_def now refers to the previously hidden definition
   234 of the empty set.
   235 
   236 * Algebra: formalization of classical algebra.  Intended as base for
   237 any algebraic development in Isabelle.  Currently covers group theory
   238 (up to Sylow's theorem) and ring theory (Universal Property of
   239 Univariate Polynomials).  Contributions welcome;
   240 
   241 * GroupTheory: deleted, since its material has been moved to Algebra;
   242 
   243 * Complex: new directory of the complex numbers with numeric constants, 
   244 nonstandard complex numbers, and some complex analysis, standard and 
   245 nonstandard (Jacques Fleuriot);
   246 
   247 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   248 
   249 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   250 Fleuriot);
   251 
   252 * Real/HahnBanach: updated and adapted to locales;
   253 
   254 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   255 Gray and Kramer);
   256 
   257 * UNITY: added the Meier-Sanders theory of progress sets;
   258 
   259 * MicroJava: bytecode verifier and lightweight bytecode verifier
   260 as abstract algorithms, instantiated to the JVM;
   261 
   262 * Bali: Java source language formalization. Type system, operational
   263 semantics, axiomatic semantics. Supported language features:
   264 classes, interfaces, objects,virtual methods, static methods,
   265 static/instance fields, arrays, access modifiers, definite
   266 assignment, exceptions.
   267 
   268 
   269 *** ZF ***
   270 
   271 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   272 universe, etc.);
   273 
   274 * Main ZF: virtually all theories converted to new-style format;
   275 
   276 
   277 *** ML ***
   278 
   279 * Pure: Tactic.prove provides sane interface for internal proofs;
   280 omits the infamous "standard" operation, so this is more appropriate
   281 than prove_goalw_cterm in many situations (e.g. in simprocs);
   282 
   283 * Pure: improved error reporting of simprocs;
   284 
   285 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   286 up simprocs;
   287 
   288 
   289 *** Document preparation ***
   290 
   291 * uses \par instead of \\ for line breaks in theory text. This may
   292 shift some page breaks in large documents. To get the old behaviour
   293 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   294 
   295 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   296 other packages
   297 
   298 * \<euro> now needs package babel/greek instead of marvosym (which
   299 broke \Rightarrow)
   300 
   301 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   302 textcomp package)
   303 
   304 
   305 New in Isabelle2002 (March 2002)
   306 --------------------------------
   307 
   308 *** Document preparation ***
   309 
   310 * greatly simplified document preparation setup, including more
   311 graceful interpretation of isatool usedir -i/-d/-D options, and more
   312 instructive isatool mkdir; users should basically be able to get
   313 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   314 users may run a separate document processing stage manually like this:
   315 "isatool usedir -D output HOL Test && isatool document Test/output";
   316 
   317 * theory dependency graph may now be incorporated into documents;
   318 isatool usedir -g true will produce session_graph.eps/.pdf for use
   319 with \includegraphics of LaTeX;
   320 
   321 * proper spacing of consecutive markup elements, especially text
   322 blocks after section headings;
   323 
   324 * support bold style (for single symbols only), input syntax is like
   325 this: "\<^bold>\<alpha>" or "\<^bold>A";
   326 
   327 * \<bullet> is now output as bold \cdot by default, which looks much
   328 better in printed text;
   329 
   330 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   331 note that these symbols are currently unavailable in Proof General /
   332 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   333 
   334 * isatool latex no longer depends on changed TEXINPUTS, instead
   335 isatool document copies the Isabelle style files to the target
   336 location;
   337 
   338 
   339 *** Isar ***
   340 
   341 * Pure/Provers: improved proof by cases and induction;
   342   - 'case' command admits impromptu naming of parameters (such as
   343     "case (Suc n)");
   344   - 'induct' method divinates rule instantiation from the inductive
   345     claim; no longer requires excessive ?P bindings for proper
   346     instantiation of cases;
   347   - 'induct' method properly enumerates all possibilities of set/type
   348     rules; as a consequence facts may be also passed through *type*
   349     rules without further ado;
   350   - 'induct' method now derives symbolic cases from the *rulified*
   351     rule (before it used to rulify cases stemming from the internal
   352     atomized version); this means that the context of a non-atomic
   353     statement becomes is included in the hypothesis, avoiding the
   354     slightly cumbersome show "PROP ?case" form;
   355   - 'induct' may now use elim-style induction rules without chaining
   356     facts, using ``missing'' premises from the goal state; this allows
   357     rules stemming from inductive sets to be applied in unstructured
   358     scripts, while still benefitting from proper handling of non-atomic
   359     statements; NB: major inductive premises need to be put first, all
   360     the rest of the goal is passed through the induction;
   361   - 'induct' proper support for mutual induction involving non-atomic
   362     rule statements (uses the new concept of simultaneous goals, see
   363     below);
   364   - append all possible rule selections, but only use the first
   365     success (no backtracking);
   366   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   367   - undeclared rule case names default to numbers 1, 2, 3, ...;
   368   - added 'print_induct_rules' (covered by help item in recent Proof
   369     General versions);
   370   - moved induct/cases attributes to Pure, methods to Provers;
   371   - generic method setup instantiated for FOL and HOL;
   372 
   373 * Pure: support multiple simultaneous goal statements, for example
   374 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   375 meta-level mechanism, this acts as if several individual goals had
   376 been stated separately; in particular common proof methods need to be
   377 repeated in order to cover all claims; note that a single elimination
   378 step is *not* sufficient to establish the two conjunctions, so this
   379 fails:
   380 
   381   assume "A & B" then have A and B ..   (*".." fails*)
   382 
   383 better use "obtain" in situations as above; alternative refer to
   384 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   385 
   386 * Pure: proper integration with ``locales''; unlike the original
   387 version by Florian Kammüller, Isar locales package high-level proof
   388 contexts rather than raw logical ones (e.g. we admit to include
   389 attributes everywhere); operations on locales include merge and
   390 rename; support for implicit arguments (``structures''); simultaneous
   391 type-inference over imports and text; see also HOL/ex/Locales.thy for
   392 some examples;
   393 
   394 * Pure: the following commands have been ``localized'', supporting a
   395 target locale specification "(in name)": 'lemma', 'theorem',
   396 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   397 stored both within the locale and at the theory level (exported and
   398 qualified by the locale name);
   399 
   400 * Pure: theory goals may now be specified in ``long'' form, with
   401 ad-hoc contexts consisting of arbitrary locale elements. for example
   402 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   403 definitions may be given, too); the result is a meta-level rule with
   404 the context elements being discharged in the obvious way;
   405 
   406 * Pure: new proof command 'using' allows to augment currently used
   407 facts after a goal statement ('using' is syntactically analogous to
   408 'apply', but acts on the goal's facts only); this allows chained facts
   409 to be separated into parts given before and after a claim, as in
   410 ``from a and b have C using d and e <proof>'';
   411 
   412 * Pure: renamed "antecedent" case to "rule_context";
   413 
   414 * Pure: new 'judgment' command records explicit information about the
   415 object-logic embedding (used by several tools internally); no longer
   416 use hard-wired "Trueprop";
   417 
   418 * Pure: added 'corollary' command;
   419 
   420 * Pure: fixed 'token_translation' command;
   421 
   422 * Pure: removed obsolete 'exported' attribute;
   423 
   424 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   425 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   426 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   427 
   428 * Pure: method 'atomize' presents local goal premises as object-level
   429 statements (atomic meta-level propositions); setup controlled via
   430 rewrite rules declarations of 'atomize' attribute; example
   431 application: 'induct' method with proper rule statements in improper
   432 proof *scripts*;
   433 
   434 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   435 now consider the syntactic context of assumptions, giving a better
   436 chance to get type-inference of the arguments right (this is
   437 especially important for locales);
   438 
   439 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   440 mode;
   441 
   442 * Pure/obtain: the formal conclusion "thesis", being marked as
   443 ``internal'', may no longer be reference directly in the text;
   444 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   445 situations;
   446 
   447 * Pure: generic 'sym' attribute which declares a rule both as pure
   448 'elim?' and for the 'symmetric' operation;
   449 
   450 * Pure: marginal comments ``--'' may now occur just anywhere in the
   451 text; the fixed correlation with particular command syntax has been
   452 discontinued;
   453 
   454 * Pure: new method 'rules' is particularly well-suited for proof
   455 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   456 but often produces more compact proof terms with less detours;
   457 
   458 * Pure/Provers/classical: simplified integration with pure rule
   459 attributes and methods; the classical "intro?/elim?/dest?"
   460 declarations coincide with the pure ones; the "rule" method no longer
   461 includes classically swapped intros; "intro" and "elim" methods no
   462 longer pick rules from the context; also got rid of ML declarations
   463 AddXIs/AddXEs/AddXDs; all of this has some potential for
   464 INCOMPATIBILITY;
   465 
   466 * Provers/classical: attribute 'swapped' produces classical inversions
   467 of introduction rules;
   468 
   469 * Provers/simplifier: 'simplified' attribute may refer to explicit
   470 rules instead of full simplifier context; 'iff' attribute handles
   471 conditional rules;
   472 
   473 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   474 
   475 * HOL: 'recdef' now fails on unfinished automated proofs, use
   476 "(permissive)" option to recover old behavior;
   477 
   478 * HOL: 'inductive' no longer features separate (collective) attributes
   479 for 'intros' (was found too confusing);
   480 
   481 * HOL: properly declared induction rules less_induct and
   482 wf_induct_rule;
   483 
   484 
   485 *** HOL ***
   486 
   487 * HOL: moved over to sane numeral syntax; the new policy is as
   488 follows:
   489 
   490   - 0 and 1 are polymorphic constants, which are defined on any
   491   numeric type (nat, int, real etc.);
   492 
   493   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   494   binary representation internally;
   495 
   496   - type nat has special constructor Suc, and generally prefers Suc 0
   497   over 1::nat and Suc (Suc 0) over 2::nat;
   498 
   499 This change may cause significant problems of INCOMPATIBILITY; here
   500 are some hints on converting existing sources:
   501 
   502   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   503   entities, so expressions involving "-" (unary or binary minus) need
   504   to be spaced properly;
   505 
   506   - existing occurrences of "1" may need to be constraint "1::nat" or
   507   even replaced by Suc 0; similar for old "2";
   508 
   509   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   510 
   511   - remove all special provisions on numerals in proofs;
   512 
   513 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   514 representation (depends on bin_arith_simps in the default context);
   515 
   516 * HOL: symbolic syntax for x^2 (numeral 2);
   517 
   518 * HOL: the class of all HOL types is now called "type" rather than
   519 "term"; INCOMPATIBILITY, need to adapt references to this type class
   520 in axclass/classes, instance/arities, and (usually rare) occurrences
   521 in typings (of consts etc.); internally the class is called
   522 "HOL.type", ML programs should refer to HOLogic.typeS;
   523 
   524 * HOL/record package improvements:
   525   - new derived operations "fields" to build a partial record section,
   526     "extend" to promote a fixed record to a record scheme, and
   527     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   528     declared as simp by default;
   529   - shared operations ("more", "fields", etc.) now need to be always
   530     qualified) --- potential INCOMPATIBILITY;
   531   - removed "make_scheme" operations (use "make" with "extend") --
   532     INCOMPATIBILITY;
   533   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   534   - provides cases/induct rules for use with corresponding Isar
   535     methods (for concrete records, record schemes, concrete more
   536     parts, and schematic more parts -- in that order);
   537   - internal definitions directly based on a light-weight abstract
   538     theory of product types over typedef rather than datatype;
   539 
   540 * HOL: generic code generator for generating executable ML code from
   541 specifications; specific support for HOL constructs such as inductive
   542 datatypes and sets, as well as recursive functions; can be invoked
   543 via 'generate_code' theory section;
   544 
   545 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   546 
   547 * HOL: consolidated and renamed several theories.  In particular:
   548 	Ord.thy has been absorbed into HOL.thy
   549 	String.thy has been absorbed into List.thy
   550  
   551 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   552 (beware of argument permutation!);
   553 
   554 * HOL: linorder_less_split superseded by linorder_cases;
   555 
   556 * HOL/List: "nodups" renamed to "distinct";
   557 
   558 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   559 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   560   - Ex_def has changed, now need to use some_eq_ex
   561 
   562 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   563 in this (rare) case use:
   564 
   565   delSWrapper "split_all_tac"
   566   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   567 
   568 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   569 MAY FAIL;
   570 
   571 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   572 Isabelle's type classes, ^ on functions and relations has too general
   573 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   574 necessary to attach explicit type constraints;
   575 
   576 * HOL/Relation: the prefix name of the infix "O" has been changed from
   577 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   578 renamed accordingly (eg "compI" -> "rel_compI").
   579 
   580 * HOL: syntax translations now work properly with numerals and records
   581 expressions;
   582 
   583 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   584 of "lam" -- INCOMPATIBILITY;
   585 
   586 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   587 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   588 renamed "Product_Type.unit";
   589 
   590 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   591 
   592 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   593 the "cases" method);
   594 
   595 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   596 Florian Kammüller);
   597 
   598 * HOL/IMP: updated and converted to new-style theory format; several
   599 parts turned into readable document, with proper Isar proof texts and
   600 some explanations (by Gerwin Klein);
   601 
   602 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   603 
   604 * HOL-Hyperreal is now a logic image;
   605 
   606 
   607 *** HOLCF ***
   608 
   609 * Isar: consts/constdefs supports mixfix syntax for continuous
   610 operations;
   611 
   612 * Isar: domain package adapted to new-style theory format, e.g. see
   613 HOLCF/ex/Dnat.thy;
   614 
   615 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   616 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   617 lift.induct_tac, always use UU instead of Undef;
   618 
   619 * HOLCF/IMP: updated and converted to new-style theory;
   620 
   621 
   622 *** ZF ***
   623 
   624 * Isar: proper integration of logic-specific tools and packages,
   625 including theory commands '(co)inductive', '(co)datatype',
   626 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   627 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   628 
   629 * theory Main no longer includes AC; for the Axiom of Choice, base
   630 your theory on Main_ZFC;
   631 
   632 * the integer library now covers quotients and remainders, with many
   633 laws relating division to addition, multiplication, etc.;
   634 
   635 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   636 typeless version of the formalism;
   637 
   638 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   639 format;
   640 
   641 * ZF/Induct: new directory for examples of inductive definitions,
   642 including theory Multiset for multiset orderings; converted to
   643 new-style theory format;
   644 
   645 * ZF: many new theorems about lists, ordinals, etc.;
   646 
   647 
   648 *** General ***
   649 
   650 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   651 variable proof controls level of detail: 0 = no proofs (only oracle
   652 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   653 also ref manual for further ML interfaces;
   654 
   655 * Pure/axclass: removed obsolete ML interface
   656 goal_subclass/goal_arity;
   657 
   658 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   659 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   660 separate tokens, so expressions involving minus need to be spaced
   661 properly;
   662 
   663 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   664 rather than "infixl" or "infixr";
   665 
   666 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   667 sort constraint specifications in type inference; e.g. "x::_::foo"
   668 ensures that the type of "x" is of sort "foo" (but not necessarily a
   669 type variable);
   670 
   671 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   672 control output of nested => (types); the default behavior is
   673 "type_brackets";
   674 
   675 * Pure/syntax: builtin parse translation for "_constify" turns valued
   676 tokens into AST constants;
   677 
   678 * Pure/syntax: prefer later declarations of translations and print
   679 translation functions; potential INCOMPATIBILITY: need to reverse
   680 multiple declarations for same syntax element constant;
   681 
   682 * Pure/show_hyps reset by default (in accordance to existing Isar
   683 practice);
   684 
   685 * Provers/classical: renamed addaltern to addafter, addSaltern to
   686 addSafter;
   687 
   688 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   689 as well;
   690 
   691 * system: tested support for MacOS X; should be able to get Isabelle +
   692 Proof General to work in a plain Terminal after installing Poly/ML
   693 (e.g. from the Isabelle distribution area) and GNU bash alone
   694 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   695 support requires further installations, e.g. from
   696 http://fink.sourceforge.net/);
   697 
   698 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   699 
   700 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   701 of 40 MB), cf. ML_OPTIONS;
   702 
   703 * system: Proof General keywords specification is now part of the
   704 Isabelle distribution (see etc/isar-keywords.el);
   705 
   706 * system: support for persistent Proof General sessions (refrain from
   707 outdating all loaded theories on startup); user may create writable
   708 logic images like this: ``isabelle -q HOL Test'';
   709 
   710 * system: smart selection of Isabelle process versus Isabelle
   711 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   712 run both "isabelle" and "Isabelle" even if file names are badly
   713 damaged (executable inspects the case of the first letter of its own
   714 name); added separate "isabelle-process" and "isabelle-interface";
   715 
   716 * system: refrain from any attempt at filtering input streams; no
   717 longer support ``8bit'' encoding of old isabelle font, instead proper
   718 iso-latin characters may now be used; the related isatools
   719 "symbolinput" and "nonascii" have disappeared as well;
   720 
   721 * system: removed old "xterm" interface (the print modes "xterm" and
   722 "xterm_color" are still available for direct use in a suitable
   723 terminal);
   724 
   725 
   726 
   727 New in Isabelle99-2 (February 2001)
   728 -----------------------------------
   729 
   730 *** Overview of INCOMPATIBILITIES ***
   731 
   732 * HOL: please note that theories in the Library and elsewhere often use the
   733 new-style (Isar) format; to refer to their theorems in an ML script you must
   734 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   735 
   736 * HOL: inductive package no longer splits induction rule aggressively,
   737 but only as far as specified by the introductions given; the old
   738 format may be recovered via ML function complete_split_rule or attribute
   739 'split_rule (complete)';
   740 
   741 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   742 gfp_Tarski to gfp_unfold;
   743 
   744 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   745 
   746 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   747 relation); infix "^^" has been renamed "``"; infix "``" has been
   748 renamed "`"; "univalent" has been renamed "single_valued";
   749 
   750 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   751 operation;
   752 
   753 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   754 
   755 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   756 
   757 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   758 consequence, it is no longer monotonic wrt. the local goal context
   759 (which is now passed through the inductive cases);
   760 
   761 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   762 \<gg> to \<ggreater>;
   763 
   764 
   765 *** Document preparation ***
   766 
   767 * \isabellestyle{NAME} selects version of Isabelle output (currently
   768 available: are "it" for near math-mode best-style output, "sl" for
   769 slanted text style, and "tt" for plain type-writer; if no
   770 \isabellestyle command is given, output is according to slanted
   771 type-writer);
   772 
   773 * support sub/super scripts (for single symbols only), input syntax is
   774 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   775 
   776 * some more standard symbols; see Appendix A of the system manual for
   777 the complete list of symbols defined in isabellesym.sty;
   778 
   779 * improved isabelle style files; more abstract symbol implementation
   780 (should now use \isamath{...} and \isatext{...} in custom symbol
   781 definitions);
   782 
   783 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   784 state; Note that presentation of goal states does not conform to
   785 actual human-readable proof documents.  Please do not include goal
   786 states into document output unless you really know what you are doing!
   787 
   788 * proper indentation of antiquoted output with proportional LaTeX
   789 fonts;
   790 
   791 * no_document ML operator temporarily disables LaTeX document
   792 generation;
   793 
   794 * isatool unsymbolize tunes sources for plain ASCII communication;
   795 
   796 
   797 *** Isar ***
   798 
   799 * Pure: Isar now suffers initial goal statements to contain unbound
   800 schematic variables (this does not conform to actual readable proof
   801 documents, due to unpredictable outcome and non-compositional proof
   802 checking); users who know what they are doing may use schematic goals
   803 for Prolog-style synthesis of proven results;
   804 
   805 * Pure: assumption method (an implicit finishing) now handles actual
   806 rules as well;
   807 
   808 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   809 initial goal, declare "that" only as Pure intro (only for single
   810 steps); the "that" rule assumption may now be involved in implicit
   811 finishing, thus ".." becomes a feasible for trivial obtains;
   812 
   813 * Pure: default proof step now includes 'intro_classes'; thus trivial
   814 instance proofs may be performed by "..";
   815 
   816 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   817 statements as well;
   818 
   819 * Pure: more robust selection of calculational rules;
   820 
   821 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   822 rule (as well as the assumption rule);
   823 
   824 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   825 lemmas, using the graph browser tool;
   826 
   827 * Pure: predict failure of "show" in interactive mode;
   828 
   829 * Pure: 'thms_containing' now takes actual terms as arguments;
   830 
   831 * HOL: improved method 'induct' --- now handles non-atomic goals
   832 (potential INCOMPATIBILITY); tuned error handling;
   833 
   834 * HOL: cases and induct rules now provide explicit hints about the
   835 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   836 any remaining facts are inserted into the goal verbatim;
   837 
   838 * HOL: local contexts (aka cases) may now contain term bindings as
   839 well; the 'cases' and 'induct' methods new provide a ?case binding for
   840 the result to be shown in each case;
   841 
   842 * HOL: added 'recdef_tc' command;
   843 
   844 * isatool convert assists in eliminating legacy ML scripts;
   845 
   846 
   847 *** HOL ***
   848 
   849 * HOL/Library: a collection of generic theories to be used together
   850 with main HOL; the theory loader path already includes this directory
   851 by default; the following existing theories have been moved here:
   852 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   853 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   854 
   855 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   856 modelling and verification task performed in Isabelle/HOL +
   857 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   858 
   859 * HOL/Algebra: special summation operator SUM no longer exists, it has
   860 been replaced by setsum; infix 'assoc' now has priority 50 (like
   861 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   862 'domain', this makes the theory consistent with mathematical
   863 literature;
   864 
   865 * HOL basics: added overloaded operations "inverse" and "divide"
   866 (infix "/"), syntax for generic "abs" operation, generic summation
   867 operator \<Sum>;
   868 
   869 * HOL/typedef: simplified package, provide more useful rules (see also
   870 HOL/subset.thy);
   871 
   872 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   873 now expressed as a proper nested rule (old-style tactic scripts may
   874 require atomize_strip_tac to cope with non-atomic premises);
   875 
   876 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   877 to "split_conv" (old name still available for compatibility);
   878 
   879 * HOL: improved concrete syntax for strings (e.g. allows translation
   880 rules with string literals);
   881 
   882 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   883  and Fleuriot's mechanization of analysis, including the transcendental
   884  functions for the reals;
   885 
   886 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   887 
   888 
   889 *** CTT ***
   890 
   891 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   892 "lam" is displayed as TWO lambda-symbols
   893 
   894 * CTT: theory Main now available, containing everything (that is, Bool
   895 and Arith);
   896 
   897 
   898 *** General ***
   899 
   900 * Pure: the Simplifier has been implemented properly as a derived rule
   901 outside of the actual kernel (at last!); the overall performance
   902 penalty in practical applications is about 50%, while reliability of
   903 the Isabelle inference kernel has been greatly improved;
   904 
   905 * print modes "brackets" and "no_brackets" control output of nested =>
   906 (types) and ==> (props); the default behaviour is "brackets";
   907 
   908 * Provers: fast_tac (and friends) now handle actual object-logic rules
   909 as assumptions as well;
   910 
   911 * system: support Poly/ML 4.0;
   912 
   913 * system: isatool install handles KDE version 1 or 2;
   914 
   915 
   916 
   917 New in Isabelle99-1 (October 2000)
   918 ----------------------------------
   919 
   920 *** Overview of INCOMPATIBILITIES ***
   921 
   922 * HOL: simplification of natural numbers is much changed; to partly
   923 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   924 issue the following ML commands:
   925 
   926   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   927   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   928 
   929 * HOL: simplification no longer dives into case-expressions; this is
   930 controlled by "t.weak_case_cong" for each datatype t;
   931 
   932 * HOL: nat_less_induct renamed to less_induct;
   933 
   934 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   935 fixsome to patch .thy and .ML sources automatically;
   936 
   937   select_equality  -> some_equality
   938   select_eq_Ex     -> some_eq_ex
   939   selectI2EX       -> someI2_ex
   940   selectI2         -> someI2
   941   selectI          -> someI
   942   select1_equality -> some1_equality
   943   Eps_sym_eq       -> some_sym_eq_trivial
   944   Eps_eq           -> some_eq_trivial
   945 
   946 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   947 
   948 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   949 instead);
   950 
   951 * HOL: the recursion equations generated by 'recdef' are now called
   952 f.simps instead of f.rules;
   953 
   954 * HOL: qed_spec_mp now also handles bounded ALL as well;
   955 
   956 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   957 sometimes be needed;
   958 
   959 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   960 
   961 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   962 
   963 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   964 product is now "<*>" instead of "Times"; the lexicographic product is
   965 now "<*lex*>" instead of "**";
   966 
   967 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   968 of main HOL, but was unused); better use HOL's datatype package;
   969 
   970 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   971 the old syntax may be recovered as follows:
   972 
   973   syntax (symbols)
   974     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   975       (infixl "\\<oplus>" 100)
   976 
   977 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   978 
   979 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   980 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   981 internally;
   982 
   983 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   984 changed from A/r to A//r;
   985 
   986 * ZF: new treatment of arithmetic (nat & int) may break some old
   987 proofs;
   988 
   989 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   990 rulify -> rule_format, elimify -> elim_format, ...);
   991 
   992 * Isar/Provers: intro/elim/dest attributes changed; renamed
   993 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   994 should have to change intro!! to intro? only); replaced "delrule" by
   995 "rule del";
   996 
   997 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   998 
   999 * Provers: strengthened force_tac by using new first_best_tac;
  1000 
  1001 * LaTeX document preparation: several changes of isabelle.sty (see
  1002 lib/texinputs);
  1003 
  1004 
  1005 *** Document preparation ***
  1006 
  1007 * formal comments (text blocks etc.) in new-style theories may now
  1008 contain antiquotations of thm/prop/term/typ/text to be presented
  1009 according to latex print mode; concrete syntax is like this:
  1010 @{term[show_types] "f(x) = a + x"};
  1011 
  1012 * isatool mkdir provides easy setup of Isabelle session directories,
  1013 including proper document sources;
  1014 
  1015 * generated LaTeX sources are now deleted after successful run
  1016 (isatool document -c); may retain a copy somewhere else via -D option
  1017 of isatool usedir;
  1018 
  1019 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1020 style files, achieving self-contained LaTeX sources and simplifying
  1021 LaTeX debugging;
  1022 
  1023 * old-style theories now produce (crude) LaTeX output as well;
  1024 
  1025 * browser info session directories are now self-contained (may be put
  1026 on WWW server seperately); improved graphs of nested sessions; removed
  1027 graph for 'all sessions';
  1028 
  1029 * several improvements in isabelle style files; \isabellestyle{it}
  1030 produces fake math mode output; \isamarkupheader is now \section by
  1031 default; see lib/texinputs/isabelle.sty etc.;
  1032 
  1033 
  1034 *** Isar ***
  1035 
  1036 * Isar/Pure: local results and corresponding term bindings are now
  1037 subject to Hindley-Milner polymorphism (similar to ML); this
  1038 accommodates incremental type-inference very nicely;
  1039 
  1040 * Isar/Pure: new derived language element 'obtain' supports
  1041 generalized existence reasoning;
  1042 
  1043 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1044 support accumulation of results, without applying any rules yet;
  1045 useful to collect intermediate results without explicit name
  1046 references, and for use with transitivity rules with more than 2
  1047 premises;
  1048 
  1049 * Isar/Pure: scalable support for case-analysis type proofs: new
  1050 'case' language element refers to local contexts symbolically, as
  1051 produced by certain proof methods; internally, case names are attached
  1052 to theorems as "tags";
  1053 
  1054 * Isar/Pure: theory command 'hide' removes declarations from
  1055 class/type/const name spaces;
  1056 
  1057 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1058 indicate potential overloading;
  1059 
  1060 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1061 
  1062 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1063 "{a,b,c}" instead of {a,b,c};
  1064 
  1065 * Isar/Pure now provides its own version of intro/elim/dest
  1066 attributes; useful for building new logics, but beware of confusion
  1067 with the version in Provers/classical;
  1068 
  1069 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1070 case name 'antecedent';
  1071 
  1072 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1073 to the current context is now done automatically);
  1074 
  1075 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1076 for definining proof methods in ML;
  1077 
  1078 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1079 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1080 most cases, one should have to change intro!! to intro? only);
  1081 replaced "delrule" by "rule del";
  1082 
  1083 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1084 'symmetric' attribute (the latter supercedes [RS sym]);
  1085 
  1086 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1087 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1088 well (including splits);
  1089 
  1090 * Isar/Provers: Simplifier and Classical methods now support all kind
  1091 of modifiers used in the past, including 'cong', 'iff', etc.
  1092 
  1093 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1094 of Simplifier and Classical reasoner);
  1095 
  1096 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1097 now support named cases; major packages (inductive, datatype, primrec,
  1098 recdef) support case names and properly name parameters;
  1099 
  1100 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1101 monotonicity conditions are extracted to be proven at end of
  1102 calculations;
  1103 
  1104 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1105 method anyway;
  1106 
  1107 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1108 split_if split_if_asm; datatype package provides theorems foo.splits =
  1109 foo.split foo.split_asm for each datatype;
  1110 
  1111 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1112 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1113 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1114 use "(cases (simplified))" method in proper proof texts);
  1115 
  1116 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1117 
  1118 * Isar: names of theorems etc. may be natural numbers as well;
  1119 
  1120 * Isar: 'pr' command: optional arguments for goals_limit and
  1121 ProofContext.prems_limit; no longer prints theory contexts, but only
  1122 proof states;
  1123 
  1124 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1125 additional print modes to be specified; e.g. "pr(latex)" will print
  1126 proof state according to the Isabelle LaTeX style;
  1127 
  1128 * Isar: improved support for emulating tactic scripts, including proof
  1129 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1130 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1131 (for HOL datatypes);
  1132 
  1133 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1134 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1135 'proof method scripts' have to be in depth-first order;
  1136 
  1137 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1138 
  1139 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1140 should instead use individual commands for printing items
  1141 (print_commands, print_methods etc.);
  1142 
  1143 * Isar: added 'nothing' --- the empty list of theorems;
  1144 
  1145 
  1146 *** HOL ***
  1147 
  1148 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1149 corresponding virtual machine and a specification of its bytecode
  1150 verifier and a lightweight bytecode verifier, including proofs of
  1151 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1152 Cornelia Pusch (see also the homepage of project Bali at
  1153 http://isabelle.in.tum.de/Bali/);
  1154 
  1155 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1156 Clemens Ballarin;
  1157 
  1158 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1159 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1160 Rasmussen;
  1161 
  1162 * HOL/Lattice: fundamental concepts of lattice theory and order
  1163 structures, including duals, properties of bounds versus algebraic
  1164 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1165 Theorem for complete lattices etc.; may also serve as a demonstration
  1166 for abstract algebraic reasoning using axiomatic type classes, and
  1167 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1168 
  1169 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1170 von Oheimb;
  1171 
  1172 * HOL/IMPP: extension of IMP with local variables and mutually
  1173 recursive procedures, by David von Oheimb;
  1174 
  1175 * HOL/Lambda: converted into new-style theory and document;
  1176 
  1177 * HOL/ex/Multiquote: example of multiple nested quotations and
  1178 anti-quotations -- basically a generalized version of de-Bruijn
  1179 representation; very useful in avoiding lifting of operations;
  1180 
  1181 * HOL/record: added general record equality rule to simpset; fixed
  1182 select-update simplification procedure to handle extended records as
  1183 well; admit "r" as field name;
  1184 
  1185 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1186 other numeric types and also as the identity of groups, rings, etc.;
  1187 
  1188 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1189 Types nat and int belong to this axclass;
  1190 
  1191 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1192    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1193    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1194   two terms #m*u and #n*u are replaced by #(m+n)*u
  1195     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1196   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1197     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1198 
  1199 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1200 powerful prover for predicate logic but knows nothing of clasets; see
  1201 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1202 
  1203 * HOL: new version of "case_tac" subsumes both boolean case split and
  1204 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1205 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1206 
  1207 * HOL: simplification no longer dives into case-expressions: only the
  1208 selector expression is simplified, but not the remaining arms; to
  1209 enable full simplification of case-expressions for datatype t, you may
  1210 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1211 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1212 
  1213 * HOL/recdef: the recursion equations generated by 'recdef' for
  1214 function 'f' are now called f.simps instead of f.rules; if all
  1215 termination conditions are proved automatically, these simplification
  1216 rules are added to the simpset, as in primrec; rules may be named
  1217 individually as well, resulting in a separate list of theorems for
  1218 each equation;
  1219 
  1220 * HOL/While is a new theory that provides a while-combinator. It
  1221 permits the definition of tail-recursive functions without the
  1222 provision of a termination measure. The latter is necessary once the
  1223 invariant proof rule for while is applied.
  1224 
  1225 * HOL: new (overloaded) notation for the set of elements below/above
  1226 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1227 
  1228 * HOL: theorems impI, allI, ballI bound as "strip";
  1229 
  1230 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1231 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1232 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1233 
  1234 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1235 
  1236 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1237 main HOL, but was unused);
  1238 
  1239 * HOL: fewer consts declared as global (e.g. have to refer to
  1240 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1241 
  1242 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1243 in case of overlap with user translations (e.g. judgements over
  1244 tuples); (note that the underlying logical represenation is still
  1245 bogus);
  1246 
  1247 
  1248 *** ZF ***
  1249 
  1250 * ZF: simplification automatically cancels common terms in arithmetic
  1251 expressions over nat and int;
  1252 
  1253 * ZF: new treatment of nat to minimize type-checking: all operators
  1254 coerce their operands to a natural number using the function natify,
  1255 making the algebraic laws unconditional;
  1256 
  1257 * ZF: as above, for int: operators coerce their operands to an integer
  1258 using the function intify;
  1259 
  1260 * ZF: the integer library now contains many of the usual laws for the
  1261 orderings, including $<=, and monotonicity laws for $+ and $*;
  1262 
  1263 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1264 simplification;
  1265 
  1266 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1267 to the simplifier and classical reasoner simultaneously;
  1268 
  1269 
  1270 *** General ***
  1271 
  1272 * Provers: blast_tac now handles actual object-logic rules as
  1273 assumptions; note that auto_tac uses blast_tac internally as well;
  1274 
  1275 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1276 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1277 
  1278 * Provers: delrules now handles destruct rules as well (no longer need
  1279 explicit make_elim);
  1280 
  1281 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1282   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1283 use instead the strong form,
  1284   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1285 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1286 from destruct-rules;
  1287 
  1288 * Provers: Simplifier.easy_setup provides a fast path to basic
  1289 Simplifier setup for new object-logics;
  1290 
  1291 * Pure: AST translation rules no longer require constant head on LHS;
  1292 
  1293 * Pure: improved name spaces: ambiguous output is qualified; support
  1294 for hiding of names;
  1295 
  1296 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1297 XSYMBOL_HOME; no longer need to do manual configuration in most
  1298 situations;
  1299 
  1300 * system: compression of ML heaps images may now be controlled via -c
  1301 option of isabelle and isatool usedir (currently only observed by
  1302 Poly/ML);
  1303 
  1304 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1305 useful for remote X11);
  1306 
  1307 * system: provide TAGS file for Isabelle sources;
  1308 
  1309 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1310 order;
  1311 
  1312 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1313 timing flag supersedes proof_timing and Toplevel.trace;
  1314 
  1315 * ML: new combinators |>> and |>>> for incremental transformations
  1316 with secondary results (e.g. certain theory extensions):
  1317 
  1318 * ML: PureThy.add_defs gets additional argument to indicate potential
  1319 overloading (usually false);
  1320 
  1321 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1322 results;
  1323 
  1324 
  1325 
  1326 New in Isabelle99 (October 1999)
  1327 --------------------------------
  1328 
  1329 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1330 
  1331 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1332 are no longer simplified.  (This allows the simplifier to unfold recursive
  1333 functional programs.)  To restore the old behaviour, declare
  1334 
  1335     Delcongs [if_weak_cong];
  1336 
  1337 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1338 complement;
  1339 
  1340 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1341 
  1342 * HOL/datatype: mutual_induct_tac no longer exists --
  1343   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1344 
  1345 * HOL/typedef: fixed type inference for representing set; type
  1346 arguments now have to occur explicitly on the rhs as type constraints;
  1347 
  1348 * ZF: The con_defs part of an inductive definition may no longer refer
  1349 to constants declared in the same theory;
  1350 
  1351 * HOL, ZF: the function mk_cases, generated by the inductive
  1352 definition package, has lost an argument.  To simplify its result, it
  1353 uses the default simpset instead of a supplied list of theorems.
  1354 
  1355 * HOL/List: the constructors of type list are now Nil and Cons;
  1356 
  1357 * Simplifier: the type of the infix ML functions
  1358         setSSolver addSSolver setSolver addSolver
  1359 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1360 for packaging solvers. A solver is created via
  1361         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1362 where the string argument is only a comment.
  1363 
  1364 
  1365 *** Proof tools ***
  1366 
  1367 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1368 decision procedure for linear arithmetic. Currently it is used for
  1369 types `nat', `int', and `real' in HOL (see below); it can, should and
  1370 will be instantiated for other types and logics as well.
  1371 
  1372 * The simplifier now accepts rewrite rules with flexible heads, eg
  1373      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1374   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1375   matching.
  1376 
  1377 
  1378 *** General ***
  1379 
  1380 * New Isabelle/Isar subsystem provides an alternative to traditional
  1381 tactical theorem proving; together with the ProofGeneral/isar user
  1382 interface it offers an interactive environment for developing human
  1383 readable proof documents (Isar == Intelligible semi-automated
  1384 reasoning); for further information see isatool doc isar-ref,
  1385 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1386 
  1387 * improved and simplified presentation of theories: better HTML markup
  1388 (including colors), graph views in several sizes; isatool usedir now
  1389 provides a proper interface for user theories (via -P option); actual
  1390 document preparation based on (PDF)LaTeX is available as well (for
  1391 new-style theories only); see isatool doc system for more information;
  1392 
  1393 * native support for Proof General, both for classic Isabelle and
  1394 Isabelle/Isar;
  1395 
  1396 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1397 using the graph browser tool;
  1398 
  1399 * Isabelle manuals now also available as PDF;
  1400 
  1401 * theory loader rewritten from scratch (may not be fully
  1402 bug-compatible); old loadpath variable has been replaced by show_path,
  1403 add_path, del_path, reset_path functions; new operations such as
  1404 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1405 isatool doc ref);
  1406 
  1407 * improved isatool install: option -k creates KDE application icon,
  1408 option -p DIR installs standalone binaries;
  1409 
  1410 * added ML_PLATFORM setting (useful for cross-platform installations);
  1411 more robust handling of platform specific ML images for SML/NJ;
  1412 
  1413 * the settings environment is now statically scoped, i.e. it is never
  1414 created again in sub-processes invoked from isabelle, isatool, or
  1415 Isabelle;
  1416 
  1417 * path element specification '~~' refers to '$ISABELLE_HOME';
  1418 
  1419 * in locales, the "assumes" and "defines" parts may be omitted if
  1420 empty;
  1421 
  1422 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1423 long arrows);
  1424 
  1425 * new print_mode "HTML";
  1426 
  1427 * new flag show_tags controls display of tags of theorems (which are
  1428 basically just comments that may be attached by some tools);
  1429 
  1430 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1431 mode and goal output format:
  1432 
  1433 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1434 244c244
  1435 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1436 ---
  1437 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1438 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1439 181c181
  1440 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1441 ---
  1442 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1443 
  1444 * function bind_thms stores lists of theorems (cf. bind_thm);
  1445 
  1446 * new shorthand tactics ftac, eatac, datac, fatac;
  1447 
  1448 * qed (and friends) now accept "" as result name; in that case the
  1449 theorem is not stored, but proper checks and presentation of the
  1450 result still apply;
  1451 
  1452 * theorem database now also indexes constants "Trueprop", "all",
  1453 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1454 
  1455 
  1456 *** HOL ***
  1457 
  1458 ** HOL arithmetic **
  1459 
  1460 * There are now decision procedures for linear arithmetic over nat and
  1461 int:
  1462 
  1463 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1464 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1465 are treated as atomic; subformulae not involving type `nat' or `int'
  1466 are ignored; quantified subformulae are ignored unless they are
  1467 positive universal or negative existential. The tactic has to be
  1468 invoked by hand and can be a little bit slow. In particular, the
  1469 running time is exponential in the number of occurrences of `min' and
  1470 `max', and `-' on `nat'.
  1471 
  1472 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1473 (negated) (in)equalities among the premises and the conclusion into
  1474 account (i.e. no compound formulae) and does not know about `min' and
  1475 `max', and `-' on `nat'. It is fast and is used automatically by the
  1476 simplifier.
  1477 
  1478 NB: At the moment, these decision procedures do not cope with mixed
  1479 nat/int formulae where the two parts interact, such as `m < n ==>
  1480 int(m) < int(n)'.
  1481 
  1482 * HOL/Numeral provides a generic theory of numerals (encoded
  1483 efficiently as bit strings); setup for types nat/int/real is in place;
  1484 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1485 int, existing theories and proof scripts may require a few additional
  1486 type constraints;
  1487 
  1488 * integer division and remainder can now be performed on constant
  1489 arguments;
  1490 
  1491 * many properties of integer multiplication, division and remainder
  1492 are now available;
  1493 
  1494 * An interface to the Stanford Validity Checker (SVC) is available through the
  1495 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1496 are proved automatically.  SVC must be installed separately, and its results
  1497 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1498 invocation of the underlying oracle).  For SVC see
  1499   http://verify.stanford.edu/SVC
  1500 
  1501 * IsaMakefile: the HOL-Real target now builds an actual image;
  1502 
  1503 
  1504 ** HOL misc **
  1505 
  1506 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1507 (in Isabelle/Isar) -- by Gertrud Bauer;
  1508 
  1509 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1510 analysis for assembly languages with subtypes;
  1511 
  1512 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1513 -- avoids syntactic ambiguities and treats state, transition, and
  1514 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1515 changed syntax and (many) tactics;
  1516 
  1517 * HOL/inductive: Now also handles more general introduction rules such
  1518   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1519   theorems are now maintained within the theory (maintained via the
  1520   "mono" attribute);
  1521 
  1522 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1523   (using function types) such as
  1524 
  1525   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1526 
  1527 * HOL/record: record_simproc (part of the default simpset) takes care
  1528 of selectors applied to updated records; record_split_tac is no longer
  1529 part of the default claset; update_defs may now be removed from the
  1530 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1531 
  1532   claset_ref () := claset() addSWrapper record_split_wrapper;
  1533   Delsimprocs [record_simproc]
  1534 
  1535 * HOL/typedef: fixed type inference for representing set; type
  1536 arguments now have to occur explicitly on the rhs as type constraints;
  1537 
  1538 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1539 names rather than an ML expression;
  1540 
  1541 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1542 supplied later.  Program schemes can be defined, such as
  1543     "While B C s = (if B s then While B C (C s) else s)"
  1544 where the well-founded relation can be chosen after B and C have been given.
  1545 
  1546 * HOL/List: the constructors of type list are now Nil and Cons;
  1547 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1548 course, ML tools referring to List.list.op # etc. have to be adapted;
  1549 
  1550 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1551 disabled by default; run isabelle with option -m HOL to get back to
  1552 the original Gordon/HOL-style output;
  1553 
  1554 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1555 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1556 
  1557 * HOL basic syntax simplified (more orthogonal): all variants of
  1558 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1559 Eps operator is provided as well: "SOME x. P[x]";
  1560 
  1561 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1562 
  1563 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1564 thus available for user theories;
  1565 
  1566 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1567 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1568 time;
  1569 
  1570 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1571 several times and then mp;
  1572 
  1573 
  1574 *** LK ***
  1575 
  1576 * the notation <<...>> is now available as a notation for sequences of
  1577 formulas;
  1578 
  1579 * the simplifier is now installed
  1580 
  1581 * the axiom system has been generalized (thanks to Soren Heilmann)
  1582 
  1583 * the classical reasoner now has a default rule database
  1584 
  1585 
  1586 *** ZF ***
  1587 
  1588 * new primrec section allows primitive recursive functions to be given
  1589 directly (as in HOL) over datatypes and the natural numbers;
  1590 
  1591 * new tactics induct_tac and exhaust_tac for induction (or case
  1592 analysis) over datatypes and the natural numbers;
  1593 
  1594 * the datatype declaration of type T now defines the recursor T_rec;
  1595 
  1596 * simplification automatically does freeness reasoning for datatype
  1597 constructors;
  1598 
  1599 * automatic type-inference, with AddTCs command to insert new
  1600 type-checking rules;
  1601 
  1602 * datatype introduction rules are now added as Safe Introduction rules
  1603 to the claset;
  1604 
  1605 * the syntax "if P then x else y" is now available in addition to
  1606 if(P,x,y);
  1607 
  1608 
  1609 *** Internal programming interfaces ***
  1610 
  1611 * tuned simplifier trace output; new flag debug_simp;
  1612 
  1613 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1614 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1615 
  1616 * AxClass.axclass_tac lost the theory argument;
  1617 
  1618 * tuned current_goals_markers semantics: begin / end goal avoids
  1619 printing empty lines;
  1620 
  1621 * removed prs and prs_fn hook, which was broken because it did not
  1622 include \n in its semantics, forcing writeln to add one
  1623 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1624 string -> unit if you really want to output text without newline;
  1625 
  1626 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1627 plain output, interface builders may have to enable 'isabelle_font'
  1628 mode to get Isabelle font glyphs as before;
  1629 
  1630 * refined token_translation interface; INCOMPATIBILITY: output length
  1631 now of type real instead of int;
  1632 
  1633 * theory loader actions may be traced via new ThyInfo.add_hook
  1634 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1635 your own database of information attached to *whole* theories -- as
  1636 opposed to intra-theory data slots offered via TheoryDataFun;
  1637 
  1638 * proper handling of dangling sort hypotheses (at last!);
  1639 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1640 extra sort hypotheses that can be witnessed from the type signature;
  1641 the force_strip_shyps flag is gone, any remaining shyps are simply
  1642 left in the theorem (with a warning issued by strip_shyps_warning);
  1643 
  1644 
  1645 
  1646 New in Isabelle98-1 (October 1998)
  1647 ----------------------------------
  1648 
  1649 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1650 
  1651 * several changes of automated proof tools;
  1652 
  1653 * HOL: major changes to the inductive and datatype packages, including
  1654 some minor incompatibilities of theory syntax;
  1655 
  1656 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1657 called `inj_on';
  1658 
  1659 * HOL: removed duplicate thms in Arith:
  1660   less_imp_add_less  should be replaced by  trans_less_add1
  1661   le_imp_add_le      should be replaced by  trans_le_add1
  1662 
  1663 * HOL: unary minus is now overloaded (new type constraints may be
  1664 required);
  1665 
  1666 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1667 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1668 now taken as an integer constant.
  1669 
  1670 * Pure: ML function 'theory_of' renamed to 'theory';
  1671 
  1672 
  1673 *** Proof tools ***
  1674 
  1675 * Simplifier:
  1676   1. Asm_full_simp_tac is now more aggressive.
  1677      1. It will sometimes reorient premises if that increases their power to
  1678         simplify.
  1679      2. It does no longer proceed strictly from left to right but may also
  1680         rotate premises to achieve further simplification.
  1681      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1682      old Asm_full_simp_tac in that it does not rotate premises.
  1683   2. The simplifier now knows a little bit about nat-arithmetic.
  1684 
  1685 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1686 allows for selected deletion of wrappers, by introduction of names for
  1687 wrapper functionals.  This implies that addbefore, addSbefore,
  1688 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1689 and that adding two tactics with the same name overwrites the first
  1690 one (emitting a warning).
  1691   type wrapper = (int -> tactic) -> (int -> tactic)
  1692   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1693   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1694   delWrapper, delSWrapper: claset *  string            -> claset
  1695   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1696 
  1697 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1698 semantics; addbefore now affects only the unsafe part of step_tac
  1699 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1700 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1701 by Force_tac;
  1702 
  1703 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1704 compWrapper; added safe wrapper (and access functions for it);
  1705 
  1706 * HOL/split_all_tac is now much faster and fails if there is nothing
  1707 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1708 and the names of the automatically generated variables have changed.
  1709 split_all_tac has moved within claset() from unsafe wrappers to safe
  1710 wrappers, which means that !!-bound variables are split much more
  1711 aggressively, and safe_tac and clarify_tac now split such variables.
  1712 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1713 Note: the same holds for record_split_tac, which does the job of
  1714 split_all_tac for record fields.
  1715 
  1716 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1717 permanently to the default simpset using Addsplits just like
  1718 Addsimps. They can be removed via Delsplits just like
  1719 Delsimps. Lower-case versions are also available.
  1720 
  1721 * HOL/Simplifier: The rule split_if is now part of the default
  1722 simpset. This means that the simplifier will eliminate all occurrences
  1723 of if-then-else in the conclusion of a goal. To prevent this, you can
  1724 either remove split_if completely from the default simpset by
  1725 `Delsplits [split_if]' or remove it in a specific call of the
  1726 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1727 other case splitting rules to/from the default simpset: every datatype
  1728 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1729 t is the name of the datatype).
  1730 
  1731 * Classical reasoner / Simplifier combination: new force_tac (and
  1732 derivatives Force_tac, force) combines rewriting and classical
  1733 reasoning (and whatever other tools) similarly to auto_tac, but is
  1734 aimed to solve the given subgoal completely.
  1735 
  1736 
  1737 *** General ***
  1738 
  1739 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1740 and `goalw': the theory is no longer needed as an explicit argument -
  1741 the current theory context is used; assumptions are no longer returned
  1742 at the ML-level unless one of them starts with ==> or !!; it is
  1743 recommended to convert to these new commands using isatool fixgoal
  1744 (backup your sources first!);
  1745 
  1746 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1747 the current theory context, and 'theory' to lookup stored theories;
  1748 
  1749 * new theory section 'locale' for declaring constants, assumptions and
  1750 definitions that have local scope;
  1751 
  1752 * new theory section 'nonterminals' for purely syntactic types;
  1753 
  1754 * new theory section 'setup' for generic ML setup functions
  1755 (e.g. package initialization);
  1756 
  1757 * the distribution now includes Isabelle icons: see
  1758 lib/logo/isabelle-{small,tiny}.xpm;
  1759 
  1760 * isatool install - install binaries with absolute references to
  1761 ISABELLE_HOME/bin;
  1762 
  1763 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1764 
  1765 * print mode 'emacs' reserved for Isamode;
  1766 
  1767 * support multiple print (ast) translations per constant name;
  1768 
  1769 * theorems involving oracles are now printed with a suffixed [!];
  1770 
  1771 
  1772 *** HOL ***
  1773 
  1774 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1775 
  1776 * HOL/inductive package reorganized and improved: now supports mutual
  1777 definitions such as
  1778 
  1779   inductive EVEN ODD
  1780     intrs
  1781       null "0 : EVEN"
  1782       oddI "n : EVEN ==> Suc n : ODD"
  1783       evenI "n : ODD ==> Suc n : EVEN"
  1784 
  1785 new theorem list "elims" contains an elimination rule for each of the
  1786 recursive sets; inductive definitions now handle disjunctive premises
  1787 correctly (also ZF);
  1788 
  1789 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1790 "mutual_induct" no longer exists - the induction rule is always
  1791 contained in "induct";
  1792 
  1793 
  1794 * HOL/datatype package re-implemented and greatly improved: now
  1795 supports mutually recursive datatypes such as
  1796 
  1797   datatype
  1798     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1799             | SUM ('a aexp) ('a aexp)
  1800             | DIFF ('a aexp) ('a aexp)
  1801             | NUM 'a
  1802   and
  1803     'a bexp = LESS ('a aexp) ('a aexp)
  1804             | AND ('a bexp) ('a bexp)
  1805             | OR ('a bexp) ('a bexp)
  1806 
  1807 as well as indirectly recursive datatypes such as
  1808 
  1809   datatype
  1810     ('a, 'b) term = Var 'a
  1811                   | App 'b ((('a, 'b) term) list)
  1812 
  1813 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1814 induction on mutually / indirectly recursive datatypes.
  1815 
  1816 Primrec equations are now stored in theory and can be accessed via
  1817 <function_name>.simps.
  1818 
  1819 INCOMPATIBILITIES:
  1820 
  1821   - Theories using datatypes must now have theory Datatype as an
  1822     ancestor.
  1823   - The specific <typename>.induct_tac no longer exists - use the
  1824     generic induct_tac instead.
  1825   - natE has been renamed to nat.exhaust - use exhaust_tac
  1826     instead of res_inst_tac ... natE. Note that the variable
  1827     names in nat.exhaust differ from the names in natE, this
  1828     may cause some "fragile" proofs to fail.
  1829   - The theorems split_<typename>_case and split_<typename>_case_asm
  1830     have been renamed to <typename>.split and <typename>.split_asm.
  1831   - Since default sorts of type variables are now handled correctly,
  1832     some datatype definitions may have to be annotated with explicit
  1833     sort constraints.
  1834   - Primrec definitions no longer require function name and type
  1835     of recursive argument.
  1836 
  1837 Consider using isatool fixdatatype to adapt your theories and proof
  1838 scripts to the new package (backup your sources first!).
  1839 
  1840 
  1841 * HOL/record package: considerably improved implementation; now
  1842 includes concrete syntax for record types, terms, updates; theorems
  1843 for surjective pairing and splitting !!-bound record variables; proof
  1844 support is as follows:
  1845 
  1846   1) standard conversions (selectors or updates applied to record
  1847 constructor terms) are part of the standard simpset;
  1848 
  1849   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1850 made part of standard simpset and claset via addIffs;
  1851 
  1852   3) a tactic for record field splitting (record_split_tac) is part of
  1853 the standard claset (addSWrapper);
  1854 
  1855 To get a better idea about these rules you may retrieve them via
  1856 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1857 the name of your record type.
  1858 
  1859 The split tactic 3) conceptually simplifies by the following rule:
  1860 
  1861   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1862 
  1863 Thus any record variable that is bound by meta-all will automatically
  1864 blow up into some record constructor term, consequently the
  1865 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1866 solve record problems automatically.
  1867 
  1868 
  1869 * reorganized the main HOL image: HOL/Integ and String loaded by
  1870 default; theory Main includes everything;
  1871 
  1872 * automatic simplification of integer sums and comparisons, using cancellation;
  1873 
  1874 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1875 
  1876 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1877 
  1878 * many new identities for unions, intersections, set difference, etc.;
  1879 
  1880 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1881 called split_if, split_split, split_sum_case and split_nat_case (to go
  1882 with add/delsplits);
  1883 
  1884 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1885 (?x::unit) = (); this is made part of the default simpset, which COULD
  1886 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1887 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1888 unit_abs_eta_conv is added in order to counter the effect of
  1889 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1890 %u.f();
  1891 
  1892 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1893 makes more sense);
  1894 
  1895 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1896   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1897   disjointness reasoning but breaking a few old proofs.
  1898 
  1899 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1900 to 'converse' from 'inverse' (for compatibility with ZF and some
  1901 literature);
  1902 
  1903 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1904 the well-founded relation;
  1905 
  1906 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1907     Compl A.  The "Compl" syntax remains available as input syntax for this
  1908     release ONLY.
  1909 
  1910 * HOL/Update: new theory of function updates:
  1911     f(a:=b) == %x. if x=a then b else f x
  1912 may also be iterated as in f(a:=b,c:=d,...);
  1913 
  1914 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1915 
  1916 * HOL/List:
  1917   - new function list_update written xs[i:=v] that updates the i-th
  1918     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1919   - new function `upt' written [i..j(] which generates the list
  1920     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1921     bound write [i..j], which is a shorthand for [i..j+1(].
  1922   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1923 
  1924 * HOL/Arith:
  1925   - removed 'pred' (predecessor) function;
  1926   - generalized some theorems about n-1;
  1927   - many new laws about "div" and "mod";
  1928   - new laws about greatest common divisors (see theory ex/Primes);
  1929 
  1930 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1931 instead of "inverse";
  1932 
  1933 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1934   of the multiset ordering;
  1935 
  1936 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1937   (not included by default);
  1938 
  1939 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1940 
  1941 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1942   programs, i.e. different program variables may have different types.
  1943 
  1944 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1945   [previously, this check worked only if the rewrite rule was unconditional]
  1946   Now rew can involve either definitions or equalities (either == or =).
  1947 
  1948 
  1949 *** ZF ***
  1950 
  1951 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1952   only the theorems proved on ZF.ML;
  1953 
  1954 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1955   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1956   disjointness reasoning but breaking a few old proofs.
  1957 
  1958 * ZF/Update: new theory of function updates
  1959     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1960   may also be iterated as in f(a:=b,c:=d,...);
  1961 
  1962 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1963 
  1964 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1965   [previously, this check worked only if the rewrite rule was unconditional]
  1966   Now rew can involve either definitions or equalities (either == or =).
  1967 
  1968 * case_tac provided for compatibility with HOL
  1969     (like the old excluded_middle_tac, but with subgoals swapped)
  1970 
  1971 
  1972 *** Internal programming interfaces ***
  1973 
  1974 * Pure: several new basic modules made available for general use, see
  1975 also src/Pure/README;
  1976 
  1977 * improved the theory data mechanism to support encapsulation (data
  1978 kind name replaced by private Object.kind, acting as authorization
  1979 key); new type-safe user interface via functor TheoryDataFun; generic
  1980 print_data function becomes basically useless;
  1981 
  1982 * removed global_names compatibility flag -- all theory declarations
  1983 are qualified by default;
  1984 
  1985 * module Pure/Syntax now offers quote / antiquote translation
  1986 functions (useful for Hoare logic etc. with implicit dependencies);
  1987 see HOL/ex/Antiquote for an example use;
  1988 
  1989 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1990 cterm -> thm;
  1991 
  1992 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1993 subgoal;
  1994 
  1995 * Display.print_goals function moved to Locale.print_goals;
  1996 
  1997 * standard print function for goals supports current_goals_markers
  1998 variable for marking begin of proof, end of proof, start of goal; the
  1999 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2000 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2001 for example;
  2002 
  2003 
  2004 
  2005 New in Isabelle98 (January 1998)
  2006 --------------------------------
  2007 
  2008 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2009 
  2010 * changed lexical syntax of terms / types: dots made part of long
  2011 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2012 
  2013 * simpset (and claset) reference variable replaced by functions
  2014 simpset / simpset_ref;
  2015 
  2016 * no longer supports theory aliases (via merge) and non-trivial
  2017 implicit merge of thms' signatures;
  2018 
  2019 * most internal names of constants changed due to qualified names;
  2020 
  2021 * changed Pure/Sequence interface (see Pure/seq.ML);
  2022 
  2023 
  2024 *** General Changes ***
  2025 
  2026 * hierachically structured name spaces (for consts, types, axms, thms
  2027 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2028 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2029 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2030 long_names for fully qualified output names; NOTE: ML programs
  2031 (special tactics, packages etc.) referring to internal names may have
  2032 to be adapted to cope with fully qualified names; in case of severe
  2033 backward campatibility problems try setting 'global_names' at compile
  2034 time to have enrything declared within a flat name space; one may also
  2035 fine tune name declarations in theories via the 'global' and 'local'
  2036 section;
  2037 
  2038 * reimplemented the implicit simpset and claset using the new anytype
  2039 data filed in signatures; references simpset:simpset ref etc. are
  2040 replaced by functions simpset:unit->simpset and
  2041 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2042 to patch your ML files accordingly;
  2043 
  2044 * HTML output now includes theory graph data for display with Java
  2045 applet or isatool browser; data generated automatically via isatool
  2046 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2047 
  2048 * defs may now be conditional; improved rewrite_goals_tac to handle
  2049 conditional equations;
  2050 
  2051 * defs now admits additional type arguments, using TYPE('a) syntax;
  2052 
  2053 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2054 creates a new theory node; implicit merge of thms' signatures is
  2055 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2056 transfer:theory->thm->thm in (rare) cases;
  2057 
  2058 * improved handling of draft signatures / theories; draft thms (and
  2059 ctyps, cterms) are automatically promoted to real ones;
  2060 
  2061 * slightly changed interfaces for oracles: admit many per theory, named
  2062 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2063 
  2064 * print_goals: optional output of const types (set show_consts and
  2065 show_types);
  2066 
  2067 * improved output of warnings (###) and errors (***);
  2068 
  2069 * subgoal_tac displays a warning if the new subgoal has type variables;
  2070 
  2071 * removed old README and Makefiles;
  2072 
  2073 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2074 
  2075 * removed obsolete init_pps and init_database;
  2076 
  2077 * deleted the obsolete tactical STATE, which was declared by
  2078     fun STATE tacfun st = tacfun st st;
  2079 
  2080 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2081 (which abbreviates $HOME);
  2082 
  2083 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2084 use isatool fixseq to adapt your ML programs (this works for fully
  2085 qualified references to the Sequence structure only!);
  2086 
  2087 * use_thy no longer requires writable current directory; it always
  2088 reloads .ML *and* .thy file, if either one is out of date;
  2089 
  2090 
  2091 *** Classical Reasoner ***
  2092 
  2093 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2094 tactics that use classical reasoning to simplify a subgoal without
  2095 splitting it into several subgoals;
  2096 
  2097 * Safe_tac: like safe_tac but uses the default claset;
  2098 
  2099 
  2100 *** Simplifier ***
  2101 
  2102 * added simplification meta rules:
  2103     (asm_)(full_)simplify: simpset -> thm -> thm;
  2104 
  2105 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2106 logics (again);
  2107 
  2108 * added prems argument to simplification procedures;
  2109 
  2110 * HOL, FOL, ZF: added infix function `addsplits':
  2111   instead of `<simpset> setloop (split_tac <thms>)'
  2112   you can simply write `<simpset> addsplits <thms>'
  2113 
  2114 
  2115 *** Syntax ***
  2116 
  2117 * TYPE('a) syntax for type reflection terms;
  2118 
  2119 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2120 
  2121 * pretty printer: changed order of mixfix annotation preference (again!);
  2122 
  2123 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2124 
  2125 
  2126 *** HOL ***
  2127 
  2128 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2129   with `addloop' of the simplifier to faciliate case splitting in premises.
  2130 
  2131 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2132 
  2133 * HOL/Auth: new protocol proofs including some for the Internet
  2134   protocol TLS;
  2135 
  2136 * HOL/Map: new theory of `maps' a la VDM;
  2137 
  2138 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2139 cancelling out common nat summands from =, <, <= (in)equalities, or
  2140 differences; simplification procedures nat_cancel_factor for
  2141 cancelling common factor from =, <, <= (in)equalities over natural
  2142 sums; nat_cancel contains both kinds of procedures, it is installed by
  2143 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2144 
  2145 * HOL/simplifier: terms of the form
  2146   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2147   are rewritten to
  2148   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2149   and those of the form
  2150   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2151   are rewritten to
  2152   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2153 
  2154 * HOL/datatype
  2155   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2156 
  2157   P(t_case f1 ... fn x) =
  2158      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2159         ...
  2160        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2161      )
  2162 
  2163   and a theorem `split_t_case_asm' of the form
  2164 
  2165   P(t_case f1 ... fn x) =
  2166     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2167         ...
  2168        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2169      )
  2170   which can be added to a simpset via `addsplits'. The existing theorems
  2171   expand_list_case and expand_option_case have been renamed to
  2172   split_list_case and split_option_case.
  2173 
  2174 * HOL/Arithmetic:
  2175   - `pred n' is automatically converted to `n-1'.
  2176     Users are strongly encouraged not to use `pred' any longer,
  2177     because it will disappear altogether at some point.
  2178   - Users are strongly encouraged to write "0 < n" rather than
  2179     "n ~= 0". Theorems and proof tools have been modified towards this
  2180     `standard'.
  2181 
  2182 * HOL/Lists:
  2183   the function "set_of_list" has been renamed "set" (and its theorems too);
  2184   the function "nth" now takes its arguments in the reverse order and
  2185   has acquired the infix notation "!" as in "xs!n".
  2186 
  2187 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2188 
  2189 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2190   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2191 
  2192 * HOL/record: extensible records with schematic structural subtyping
  2193 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2194 still lacks various theorems and concrete record syntax;
  2195 
  2196 
  2197 *** HOLCF ***
  2198 
  2199 * removed "axioms" and "generated by" sections;
  2200 
  2201 * replaced "ops" section by extended "consts" section, which is capable of
  2202   handling the continuous function space "->" directly;
  2203 
  2204 * domain package:
  2205   . proves theorems immediately and stores them in the theory,
  2206   . creates hierachical name space,
  2207   . now uses normal mixfix annotations (instead of cinfix...),
  2208   . minor changes to some names and values (for consistency),
  2209   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2210   . separator between mutual domain defs: changed "," to "and",
  2211   . improved handling of sort constraints;  now they have to
  2212     appear on the left-hand side of the equations only;
  2213 
  2214 * fixed LAM <x,y,zs>.b syntax;
  2215 
  2216 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2217 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2218 
  2219 
  2220 *** FOL and ZF ***
  2221 
  2222 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2223   with `addloop' of the simplifier to faciliate case splitting in premises.
  2224 
  2225 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2226 in HOL, they strip ALL and --> from proved theorems;
  2227 
  2228 
  2229 
  2230 New in Isabelle94-8 (May 1997)
  2231 ------------------------------
  2232 
  2233 *** General Changes ***
  2234 
  2235 * new utilities to build / run / maintain Isabelle etc. (in parts
  2236 still somewhat experimental); old Makefiles etc. still functional;
  2237 
  2238 * new 'Isabelle System Manual';
  2239 
  2240 * INSTALL text, together with ./configure and ./build scripts;
  2241 
  2242 * reimplemented type inference for greater efficiency, better error
  2243 messages and clean internal interface;
  2244 
  2245 * prlim command for dealing with lots of subgoals (an easier way of
  2246 setting goals_limit);
  2247 
  2248 
  2249 *** Syntax ***
  2250 
  2251 * supports alternative (named) syntax tables (parser and pretty
  2252 printer); internal interface is provided by add_modesyntax(_i);
  2253 
  2254 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2255 be used in conjunction with the Isabelle symbol font; uses the
  2256 "symbols" syntax table;
  2257 
  2258 * added token_translation interface (may translate name tokens in
  2259 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2260 the current print_mode); IMPORTANT: user print translation functions
  2261 are responsible for marking newly introduced bounds
  2262 (Syntax.mark_boundT);
  2263 
  2264 * token translations for modes "xterm" and "xterm_color" that display
  2265 names in bold, underline etc. or colors (which requires a color
  2266 version of xterm);
  2267 
  2268 * infixes may now be declared with names independent of their syntax;
  2269 
  2270 * added typed_print_translation (like print_translation, but may
  2271 access type of constant);
  2272 
  2273 
  2274 *** Classical Reasoner ***
  2275 
  2276 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2277 some limitations.  Blast_tac...
  2278   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2279   + ignores elimination rules that don't have the correct format
  2280         (the conclusion MUST be a formula variable)
  2281   + ignores types, which can make HOL proofs fail
  2282   + rules must not require higher-order unification, e.g. apply_type in ZF
  2283     [message "Function Var's argument not a bound variable" relates to this]
  2284   + its proof strategy is more general but can actually be slower
  2285 
  2286 * substitution with equality assumptions no longer permutes other
  2287 assumptions;
  2288 
  2289 * minor changes in semantics of addafter (now called addaltern); renamed
  2290 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2291 (and access functions for it);
  2292 
  2293 * improved combination of classical reasoner and simplifier:
  2294   + functions for handling clasimpsets
  2295   + improvement of addss: now the simplifier is called _after_ the
  2296     safe steps.
  2297   + safe variant of addss called addSss: uses safe simplifications
  2298     _during_ the safe steps. It is more complete as it allows multiple
  2299     instantiations of unknowns (e.g. with slow_tac).
  2300 
  2301 *** Simplifier ***
  2302 
  2303 * added interface for simplification procedures (functions that
  2304 produce *proven* rewrite rules on the fly, depending on current
  2305 redex);
  2306 
  2307 * ordering on terms as parameter (used for ordered rewriting);
  2308 
  2309 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2310 
  2311 * the solver is now split into a safe and an unsafe part.
  2312 This should be invisible for the normal user, except that the
  2313 functions setsolver and addsolver have been renamed to setSolver and
  2314 addSolver; added safe_asm_full_simp_tac;
  2315 
  2316 
  2317 *** HOL ***
  2318 
  2319 * a generic induction tactic `induct_tac' which works for all datatypes and
  2320 also for type `nat';
  2321 
  2322 * a generic case distinction tactic `exhaust_tac' which works for all
  2323 datatypes and also for type `nat';
  2324 
  2325 * each datatype comes with a function `size';
  2326 
  2327 * patterns in case expressions allow tuple patterns as arguments to
  2328 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2329 
  2330 * primrec now also works with type nat;
  2331 
  2332 * recdef: a new declaration form, allows general recursive functions to be
  2333 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2334 
  2335 * the constant for negation has been renamed from "not" to "Not" to
  2336 harmonize with FOL, ZF, LK, etc.;
  2337 
  2338 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2339 infinite lists;
  2340 
  2341 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2342 
  2343 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2344 problems in commutative rings, using axiomatic type classes for + and *;
  2345 
  2346 * more examples in HOL/MiniML and HOL/Auth;
  2347 
  2348 * more default rewrite rules for quantifiers, union/intersection;
  2349 
  2350 * a new constant `arbitrary == @x.False';
  2351 
  2352 * HOLCF/IOA replaces old HOL/IOA;
  2353 
  2354 * HOLCF changes: derived all rules and arities
  2355   + axiomatic type classes instead of classes
  2356   + typedef instead of faking type definitions
  2357   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2358   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2359   + eliminated the types void, one, tr
  2360   + use unit lift and bool lift (with translations) instead of one and tr
  2361   + eliminated blift from Lift3.thy (use Def instead of blift)
  2362   all eliminated rules are derived as theorems --> no visible changes ;
  2363 
  2364 
  2365 *** ZF ***
  2366 
  2367 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2368 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2369 as ZF_cs addSIs [equalityI];
  2370 
  2371 
  2372 
  2373 New in Isabelle94-7 (November 96)
  2374 ---------------------------------
  2375 
  2376 * allowing negative levels (as offsets) in prlev and choplev;
  2377 
  2378 * super-linear speedup for large simplifications;
  2379 
  2380 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2381 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2382 FAIL); can suppress it using the command Delsimps (ex_simps @
  2383 all_simps); De Morgan laws are also now included, by default;
  2384 
  2385 * improved printing of ==>  :  ~:
  2386 
  2387 * new object-logic "Sequents" adds linear logic, while replacing LK
  2388 and Modal (thanks to Sara Kalvala);
  2389 
  2390 * HOL/Auth: correctness proofs for authentication protocols;
  2391 
  2392 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2393 examples on HOL/Auth);
  2394 
  2395 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2396 the rewriter and classical reasoner simultaneously;
  2397 
  2398 * function uresult no longer returns theorems in "standard" format;
  2399 regain previous version by: val uresult = standard o uresult;
  2400 
  2401 
  2402 
  2403 New in Isabelle94-6
  2404 -------------------
  2405 
  2406 * oracles -- these establish an interface between Isabelle and trusted
  2407 external reasoners, which may deliver results as theorems;
  2408 
  2409 * proof objects (in particular record all uses of oracles);
  2410 
  2411 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2412 
  2413 * "constdefs" section in theory files;
  2414 
  2415 * "primrec" section (HOL) no longer requires names;
  2416 
  2417 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2418 
  2419 
  2420 
  2421 New in Isabelle94-5
  2422 -------------------
  2423 
  2424 * reduced space requirements;
  2425 
  2426 * automatic HTML generation from theories;
  2427 
  2428 * theory files no longer require "..." (quotes) around most types;
  2429 
  2430 * new examples, including two proofs of the Church-Rosser theorem;
  2431 
  2432 * non-curried (1994) version of HOL is no longer distributed;
  2433 
  2434 
  2435 
  2436 New in Isabelle94-4
  2437 -------------------
  2438 
  2439 * greatly reduced space requirements;
  2440 
  2441 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2442 
  2443 * searchable theorem database (see the section "Retrieving theorems" on
  2444 page 8 of the Reference Manual);
  2445 
  2446 * new examples, including Grabczewski's monumental case study of the
  2447 Axiom of Choice;
  2448 
  2449 * The previous version of HOL renamed to Old_HOL;
  2450 
  2451 * The new version of HOL (previously called CHOL) uses a curried syntax
  2452 for functions.  Application looks like f a b instead of f(a,b);
  2453 
  2454 * Mutually recursive inductive definitions finally work in HOL;
  2455 
  2456 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2457 translates to the operator "split";
  2458 
  2459 
  2460 
  2461 New in Isabelle94-3
  2462 -------------------
  2463 
  2464 * new infix operator, addss, allowing the classical reasoner to
  2465 perform simplification at each step of its search.  Example:
  2466         fast_tac (cs addss ss)
  2467 
  2468 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2469 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2470 look like (a,b) instead of <a,b>;
  2471 
  2472 * PLEASE NOTE: CHOL will eventually replace HOL!
  2473 
  2474 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2475 It translates to the operator "split".  A new theory of integers is available;
  2476 
  2477 * In ZF, integer numerals now denote two's-complement binary integers.
  2478 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2479 
  2480 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2481 of the Axiom of Choice;
  2482 
  2483 
  2484 
  2485 New in Isabelle94-2
  2486 -------------------
  2487 
  2488 * Significantly faster resolution;
  2489 
  2490 * the different sections in a .thy file can now be mixed and repeated
  2491 freely;
  2492 
  2493 * Database of theorems for FOL, HOL and ZF.  New
  2494 commands including qed, qed_goal and bind_thm store theorems in the database.
  2495 
  2496 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2497 a given theory (thms_of), or find out what theory a theorem was proved in
  2498 (theory_of_thm);
  2499 
  2500 * Bugs fixed in the inductive definition and datatype packages;
  2501 
  2502 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2503 and HOL_dup_cs obsolete;
  2504 
  2505 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2506 have been removed;
  2507 
  2508 * Simpler definition of function space in ZF;
  2509 
  2510 * new results about cardinal and ordinal arithmetic in ZF;
  2511 
  2512 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2513 types;
  2514 
  2515 
  2516 $Id$