NEWS
author ballarin
Thu Nov 06 14:18:05 2003 +0100 (2003-11-06)
changeset 14254 342634f38451
parent 14243 0e2ec694784d
child 14255 e6e3e3f0deed
permissions -rw-r--r--
Isar/Locales: <loc>.intro and <loc>.axioms no longer intro? and elim? by
default.
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Pure: Greek letters (except small lambda, \<lambda>), as well as gothic
    10   (\<aa>...\<zz>\<AA>...\<ZZ>), caligraphic (\<A>...\<Z>), and euler
    11   (\<a>...\<z>), are now considered normal letters, and can therefore
    12   be used anywhere where an ASCII letter (a...zA...Z) has until
    13   now. COMPATIBILITY: This obviously changes the parsing of some
    14   terms, especially where a symbol has been used as a binder, say
    15   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
    16   as an identifier.  Fix it by inserting a space around former
    17   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
    18   existing theory and ML files.
    19 
    20 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
    21 
    22 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now 
    23   allowed in identifiers. Similar to greek letters \<^isub> is now considered 
    24   a normal (but invisible) letter. For multiple letter subscripts repeat 
    25   \<^isub> like this: x\<^isub>1\<^isub>2. 
    26 
    27 * Pure: Using new Isar command "finalconsts" (or the ML functions
    28   Theory.add_finals or Theory.add_finals_i) it is now possible to
    29   declare constants "final", which prevents their being given a definition
    30   later.  It is useful for constants whose behaviour is fixed axiomatically
    31   rather than definitionally, such as the meta-logic connectives.
    32 
    33 *** Isar ***
    34 
    35 * Tactic emulation methods ?rule_tac, cut_tac, subgoal_tac and thin_tac:
    36   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    37     locales are no longer forced to write Isar proof scripts.
    38     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    39     emulations.
    40   - INCOMPATIBILITY: names of variables to be instantiated may no
    41     longer be enclosed in quotes.  Instead, precede variable name with `?'.
    42     This is consistent with the instantiation attribute "where".
    43 
    44 * Locales:
    45   - Goal statements involving the context element "includes" no longer
    46     generate theorems with internal delta predicates (those ending on
    47     "_axioms") in the premise.
    48     Resolve particular premise with <locale>.intro to obtain old form.
    49   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
    50     specification and "includes" elements in goal statement.
    51   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
    52     [intro?] and [elim?] (respectively) by default.
    53 
    54 * HOL: Tactic emulation methods induct_tac and case_tac understand static
    55   (Isar) contexts.
    56 
    57 *** HOL ***
    58 
    59 * 'specification' command added, allowing for definition by
    60   specification.  There is also an 'ax_specification' command that
    61   introduces the new constants axiomatically.
    62 
    63 * SET-Protocol: formalization and verification of the SET protocol suite;
    64 
    65 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
    66  defintions, thanks to Sava Krsti\'{c} and John Matthews.
    67 
    68 New in Isabelle2003 (May 2003)
    69 --------------------------------
    70 
    71 *** General ***
    72 
    73 * Provers/simplifier:
    74 
    75   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
    76     Assumptions are now subject to complete mutual simplification,
    77     not just from left to right. The simplifier now preserves
    78     the order of assumptions.
    79 
    80     Potential INCOMPATIBILITY:
    81 
    82     -- simp sometimes diverges where the old version did
    83        not, e.g. invoking simp on the goal
    84 
    85         [| P (f x); y = x; f x = f y |] ==> Q
    86 
    87        now gives rise to the infinite reduction sequence
    88 
    89         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
    90 
    91        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
    92        kind of problem.
    93 
    94     -- Tactics combining classical reasoner and simplification (such as auto)
    95        are also affected by this change, because many of them rely on
    96        simp. They may sometimes diverge as well or yield a different numbers
    97        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
    98        in case of problems. Sometimes subsequent calls to the classical
    99        reasoner will fail because a preceeding call to the simplifier too
   100        eagerly simplified the goal, e.g. deleted redundant premises.
   101 
   102   - The simplifier trace now shows the names of the applied rewrite rules
   103 
   104   - You can limit the number of recursive invocations of the simplifier
   105     during conditional rewriting (where the simplifie tries to solve the
   106     conditions before applying the rewrite rule):
   107     ML "simp_depth_limit := n"
   108     where n is an integer. Thus you can force termination where previously
   109     the simplifier would diverge.
   110 
   111   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   112 
   113   - No longer aborts on failed congruence proof.  Instead, the
   114     congruence is ignored.
   115 
   116 * Pure: New generic framework for extracting programs from constructive
   117   proofs. See HOL/Extraction.thy for an example instantiation, as well
   118   as HOL/Extraction for some case studies.
   119 
   120 * Pure: The main goal of the proof state is no longer shown by default, only
   121 the subgoals. This behaviour is controlled by a new flag.
   122    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   123 (ML: Proof.show_main_goal).
   124 
   125 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   126 rules whose conclusion matches subgoal 1:
   127       PG menu: Isabelle/Isar -> Show me -> matching rules
   128 The rules are ordered by how closely they match the subgoal.
   129 In particular, rules that solve a subgoal outright are displayed first
   130 (or rather last, the way they are printed).
   131 (ML: ProofGeneral.print_intros())
   132 
   133 * Pure: New flag trace_unify_fail causes unification to print
   134 diagnostic information (PG: in trace buffer) when it fails. This is
   135 useful for figuring out why single step proofs like rule, erule or
   136 assumption failed.
   137 
   138 * Pure: Locale specifications now produce predicate definitions
   139 according to the body of text (covering assumptions modulo local
   140 definitions); predicate "loc_axioms" covers newly introduced text,
   141 while "loc" is cumulative wrt. all included locale expressions; the
   142 latter view is presented only on export into the global theory
   143 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   144 on the old view without predicates;
   145 
   146 * Pure: predefined locales "var" and "struct" are useful for sharing
   147 parameters (as in CASL, for example); just specify something like
   148 ``var x + var y + struct M'' as import;
   149 
   150 * Pure: improved thms_containing: proper indexing of facts instead of
   151 raw theorems; check validity of results wrt. current name space;
   152 include local facts of proof configuration (also covers active
   153 locales), cover fixed variables in index; may use "_" in term
   154 specification; an optional limit for the number of printed facts may
   155 be given (the default is 40);
   156 
   157 * Pure: disallow duplicate fact bindings within new-style theory files
   158 (batch-mode only);
   159 
   160 * Provers: improved induct method: assumptions introduced by case
   161 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   162 the goal statement); "foo" still refers to all facts collectively;
   163 
   164 * Provers: the function blast.overloaded has been removed: all constants
   165 are regarded as potentially overloaded, which improves robustness in exchange
   166 for slight decrease in efficiency;
   167 
   168 * Provers/linorder: New generic prover for transitivity reasoning over
   169 linear orders.  Note: this prover is not efficient!
   170 
   171 * Isar: preview of problems to finish 'show' now produce an error
   172 rather than just a warning (in interactive mode);
   173 
   174 
   175 *** HOL ***
   176 
   177 * arith(_tac)
   178 
   179  - Produces a counter example if it cannot prove a goal.
   180    Note that the counter example may be spurious if the goal is not a formula
   181    of quantifier-free linear arithmetic.
   182    In ProofGeneral the counter example appears in the trace buffer.
   183 
   184  - Knows about div k and mod k where k is a numeral of type nat or int.
   185 
   186  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   187    linear arithmetic fails. This takes account of quantifiers and divisibility.
   188    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   189 
   190 * simp's arithmetic capabilities have been enhanced a bit: it now
   191 takes ~= in premises into account (by performing a case split);
   192 
   193 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   194 are distributed over a sum of terms;
   195 
   196 * New tactic "trans_tac" and method "trans" instantiate
   197 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   198 "<=", "<" and "="). 
   199 
   200 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   201 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   202 
   203 * 'typedef' command has new option "open" to suppress the set
   204 definition;
   205 
   206 * functions Min and Max on finite sets have been introduced (theory
   207 Finite_Set);
   208 
   209 * attribute [symmetric] now works for relations as well; it turns
   210 (x,y) : R^-1 into (y,x) : R, and vice versa;
   211 
   212 * induct over a !!-quantified statement (say !!x1..xn):
   213   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   214 
   215 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   216 %x. None. Warning: empty_def now refers to the previously hidden definition
   217 of the empty set.
   218 
   219 * Algebra: formalization of classical algebra.  Intended as base for
   220 any algebraic development in Isabelle.  Currently covers group theory
   221 (up to Sylow's theorem) and ring theory (Universal Property of
   222 Univariate Polynomials).  Contributions welcome;
   223 
   224 * GroupTheory: deleted, since its material has been moved to Algebra;
   225 
   226 * Complex: new directory of the complex numbers with numeric constants, 
   227 nonstandard complex numbers, and some complex analysis, standard and 
   228 nonstandard (Jacques Fleuriot);
   229 
   230 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   231 
   232 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   233 Fleuriot);
   234 
   235 * Real/HahnBanach: updated and adapted to locales;
   236 
   237 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   238 Gray and Kramer);
   239 
   240 * UNITY: added the Meier-Sanders theory of progress sets;
   241 
   242 * MicroJava: bytecode verifier and lightweight bytecode verifier
   243 as abstract algorithms, instantiated to the JVM;
   244 
   245 * Bali: Java source language formalization. Type system, operational
   246 semantics, axiomatic semantics. Supported language features:
   247 classes, interfaces, objects,virtual methods, static methods,
   248 static/instance fields, arrays, access modifiers, definite
   249 assignment, exceptions.
   250 
   251 
   252 *** ZF ***
   253 
   254 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   255 universe, etc.);
   256 
   257 * Main ZF: virtually all theories converted to new-style format;
   258 
   259 
   260 *** ML ***
   261 
   262 * Pure: Tactic.prove provides sane interface for internal proofs;
   263 omits the infamous "standard" operation, so this is more appropriate
   264 than prove_goalw_cterm in many situations (e.g. in simprocs);
   265 
   266 * Pure: improved error reporting of simprocs;
   267 
   268 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   269 up simprocs;
   270 
   271 
   272 *** Document preparation ***
   273 
   274 * uses \par instead of \\ for line breaks in theory text. This may
   275 shift some page breaks in large documents. To get the old behaviour
   276 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   277 
   278 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   279 other packages
   280 
   281 * \<euro> now needs package babel/greek instead of marvosym (which
   282 broke \Rightarrow)
   283 
   284 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   285 textcomp package)
   286 
   287 
   288 New in Isabelle2002 (March 2002)
   289 --------------------------------
   290 
   291 *** Document preparation ***
   292 
   293 * greatly simplified document preparation setup, including more
   294 graceful interpretation of isatool usedir -i/-d/-D options, and more
   295 instructive isatool mkdir; users should basically be able to get
   296 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   297 users may run a separate document processing stage manually like this:
   298 "isatool usedir -D output HOL Test && isatool document Test/output";
   299 
   300 * theory dependency graph may now be incorporated into documents;
   301 isatool usedir -g true will produce session_graph.eps/.pdf for use
   302 with \includegraphics of LaTeX;
   303 
   304 * proper spacing of consecutive markup elements, especially text
   305 blocks after section headings;
   306 
   307 * support bold style (for single symbols only), input syntax is like
   308 this: "\<^bold>\<alpha>" or "\<^bold>A";
   309 
   310 * \<bullet> is now output as bold \cdot by default, which looks much
   311 better in printed text;
   312 
   313 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   314 note that these symbols are currently unavailable in Proof General /
   315 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   316 
   317 * isatool latex no longer depends on changed TEXINPUTS, instead
   318 isatool document copies the Isabelle style files to the target
   319 location;
   320 
   321 
   322 *** Isar ***
   323 
   324 * Pure/Provers: improved proof by cases and induction;
   325   - 'case' command admits impromptu naming of parameters (such as
   326     "case (Suc n)");
   327   - 'induct' method divinates rule instantiation from the inductive
   328     claim; no longer requires excessive ?P bindings for proper
   329     instantiation of cases;
   330   - 'induct' method properly enumerates all possibilities of set/type
   331     rules; as a consequence facts may be also passed through *type*
   332     rules without further ado;
   333   - 'induct' method now derives symbolic cases from the *rulified*
   334     rule (before it used to rulify cases stemming from the internal
   335     atomized version); this means that the context of a non-atomic
   336     statement becomes is included in the hypothesis, avoiding the
   337     slightly cumbersome show "PROP ?case" form;
   338   - 'induct' may now use elim-style induction rules without chaining
   339     facts, using ``missing'' premises from the goal state; this allows
   340     rules stemming from inductive sets to be applied in unstructured
   341     scripts, while still benefitting from proper handling of non-atomic
   342     statements; NB: major inductive premises need to be put first, all
   343     the rest of the goal is passed through the induction;
   344   - 'induct' proper support for mutual induction involving non-atomic
   345     rule statements (uses the new concept of simultaneous goals, see
   346     below);
   347   - append all possible rule selections, but only use the first
   348     success (no backtracking);
   349   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   350   - undeclared rule case names default to numbers 1, 2, 3, ...;
   351   - added 'print_induct_rules' (covered by help item in recent Proof
   352     General versions);
   353   - moved induct/cases attributes to Pure, methods to Provers;
   354   - generic method setup instantiated for FOL and HOL;
   355 
   356 * Pure: support multiple simultaneous goal statements, for example
   357 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   358 meta-level mechanism, this acts as if several individual goals had
   359 been stated separately; in particular common proof methods need to be
   360 repeated in order to cover all claims; note that a single elimination
   361 step is *not* sufficient to establish the two conjunctions, so this
   362 fails:
   363 
   364   assume "A & B" then have A and B ..   (*".." fails*)
   365 
   366 better use "obtain" in situations as above; alternative refer to
   367 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   368 
   369 * Pure: proper integration with ``locales''; unlike the original
   370 version by Florian Kammüller, Isar locales package high-level proof
   371 contexts rather than raw logical ones (e.g. we admit to include
   372 attributes everywhere); operations on locales include merge and
   373 rename; support for implicit arguments (``structures''); simultaneous
   374 type-inference over imports and text; see also HOL/ex/Locales.thy for
   375 some examples;
   376 
   377 * Pure: the following commands have been ``localized'', supporting a
   378 target locale specification "(in name)": 'lemma', 'theorem',
   379 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   380 stored both within the locale and at the theory level (exported and
   381 qualified by the locale name);
   382 
   383 * Pure: theory goals may now be specified in ``long'' form, with
   384 ad-hoc contexts consisting of arbitrary locale elements. for example
   385 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   386 definitions may be given, too); the result is a meta-level rule with
   387 the context elements being discharged in the obvious way;
   388 
   389 * Pure: new proof command 'using' allows to augment currently used
   390 facts after a goal statement ('using' is syntactically analogous to
   391 'apply', but acts on the goal's facts only); this allows chained facts
   392 to be separated into parts given before and after a claim, as in
   393 ``from a and b have C using d and e <proof>'';
   394 
   395 * Pure: renamed "antecedent" case to "rule_context";
   396 
   397 * Pure: new 'judgment' command records explicit information about the
   398 object-logic embedding (used by several tools internally); no longer
   399 use hard-wired "Trueprop";
   400 
   401 * Pure: added 'corollary' command;
   402 
   403 * Pure: fixed 'token_translation' command;
   404 
   405 * Pure: removed obsolete 'exported' attribute;
   406 
   407 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   408 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   409 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   410 
   411 * Pure: method 'atomize' presents local goal premises as object-level
   412 statements (atomic meta-level propositions); setup controlled via
   413 rewrite rules declarations of 'atomize' attribute; example
   414 application: 'induct' method with proper rule statements in improper
   415 proof *scripts*;
   416 
   417 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   418 now consider the syntactic context of assumptions, giving a better
   419 chance to get type-inference of the arguments right (this is
   420 especially important for locales);
   421 
   422 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   423 mode;
   424 
   425 * Pure/obtain: the formal conclusion "thesis", being marked as
   426 ``internal'', may no longer be reference directly in the text;
   427 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   428 situations;
   429 
   430 * Pure: generic 'sym' attribute which declares a rule both as pure
   431 'elim?' and for the 'symmetric' operation;
   432 
   433 * Pure: marginal comments ``--'' may now occur just anywhere in the
   434 text; the fixed correlation with particular command syntax has been
   435 discontinued;
   436 
   437 * Pure: new method 'rules' is particularly well-suited for proof
   438 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   439 but often produces more compact proof terms with less detours;
   440 
   441 * Pure/Provers/classical: simplified integration with pure rule
   442 attributes and methods; the classical "intro?/elim?/dest?"
   443 declarations coincide with the pure ones; the "rule" method no longer
   444 includes classically swapped intros; "intro" and "elim" methods no
   445 longer pick rules from the context; also got rid of ML declarations
   446 AddXIs/AddXEs/AddXDs; all of this has some potential for
   447 INCOMPATIBILITY;
   448 
   449 * Provers/classical: attribute 'swapped' produces classical inversions
   450 of introduction rules;
   451 
   452 * Provers/simplifier: 'simplified' attribute may refer to explicit
   453 rules instead of full simplifier context; 'iff' attribute handles
   454 conditional rules;
   455 
   456 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   457 
   458 * HOL: 'recdef' now fails on unfinished automated proofs, use
   459 "(permissive)" option to recover old behavior;
   460 
   461 * HOL: 'inductive' no longer features separate (collective) attributes
   462 for 'intros' (was found too confusing);
   463 
   464 * HOL: properly declared induction rules less_induct and
   465 wf_induct_rule;
   466 
   467 
   468 *** HOL ***
   469 
   470 * HOL: moved over to sane numeral syntax; the new policy is as
   471 follows:
   472 
   473   - 0 and 1 are polymorphic constants, which are defined on any
   474   numeric type (nat, int, real etc.);
   475 
   476   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   477   binary representation internally;
   478 
   479   - type nat has special constructor Suc, and generally prefers Suc 0
   480   over 1::nat and Suc (Suc 0) over 2::nat;
   481 
   482 This change may cause significant problems of INCOMPATIBILITY; here
   483 are some hints on converting existing sources:
   484 
   485   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   486   entities, so expressions involving "-" (unary or binary minus) need
   487   to be spaced properly;
   488 
   489   - existing occurrences of "1" may need to be constraint "1::nat" or
   490   even replaced by Suc 0; similar for old "2";
   491 
   492   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   493 
   494   - remove all special provisions on numerals in proofs;
   495 
   496 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   497 representation (depends on bin_arith_simps in the default context);
   498 
   499 * HOL: symbolic syntax for x^2 (numeral 2);
   500 
   501 * HOL: the class of all HOL types is now called "type" rather than
   502 "term"; INCOMPATIBILITY, need to adapt references to this type class
   503 in axclass/classes, instance/arities, and (usually rare) occurrences
   504 in typings (of consts etc.); internally the class is called
   505 "HOL.type", ML programs should refer to HOLogic.typeS;
   506 
   507 * HOL/record package improvements:
   508   - new derived operations "fields" to build a partial record section,
   509     "extend" to promote a fixed record to a record scheme, and
   510     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   511     declared as simp by default;
   512   - shared operations ("more", "fields", etc.) now need to be always
   513     qualified) --- potential INCOMPATIBILITY;
   514   - removed "make_scheme" operations (use "make" with "extend") --
   515     INCOMPATIBILITY;
   516   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   517   - provides cases/induct rules for use with corresponding Isar
   518     methods (for concrete records, record schemes, concrete more
   519     parts, and schematic more parts -- in that order);
   520   - internal definitions directly based on a light-weight abstract
   521     theory of product types over typedef rather than datatype;
   522 
   523 * HOL: generic code generator for generating executable ML code from
   524 specifications; specific support for HOL constructs such as inductive
   525 datatypes and sets, as well as recursive functions; can be invoked
   526 via 'generate_code' theory section;
   527 
   528 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   529 
   530 * HOL: consolidated and renamed several theories.  In particular:
   531 	Ord.thy has been absorbed into HOL.thy
   532 	String.thy has been absorbed into List.thy
   533  
   534 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   535 (beware of argument permutation!);
   536 
   537 * HOL: linorder_less_split superseded by linorder_cases;
   538 
   539 * HOL/List: "nodups" renamed to "distinct";
   540 
   541 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   542 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   543   - Ex_def has changed, now need to use some_eq_ex
   544 
   545 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   546 in this (rare) case use:
   547 
   548   delSWrapper "split_all_tac"
   549   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   550 
   551 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   552 MAY FAIL;
   553 
   554 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   555 Isabelle's type classes, ^ on functions and relations has too general
   556 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   557 necessary to attach explicit type constraints;
   558 
   559 * HOL/Relation: the prefix name of the infix "O" has been changed from
   560 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   561 renamed accordingly (eg "compI" -> "rel_compI").
   562 
   563 * HOL: syntax translations now work properly with numerals and records
   564 expressions;
   565 
   566 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   567 of "lam" -- INCOMPATIBILITY;
   568 
   569 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   570 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   571 renamed "Product_Type.unit";
   572 
   573 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   574 
   575 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   576 the "cases" method);
   577 
   578 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   579 Florian Kammüller);
   580 
   581 * HOL/IMP: updated and converted to new-style theory format; several
   582 parts turned into readable document, with proper Isar proof texts and
   583 some explanations (by Gerwin Klein);
   584 
   585 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   586 
   587 * HOL-Hyperreal is now a logic image;
   588 
   589 
   590 *** HOLCF ***
   591 
   592 * Isar: consts/constdefs supports mixfix syntax for continuous
   593 operations;
   594 
   595 * Isar: domain package adapted to new-style theory format, e.g. see
   596 HOLCF/ex/Dnat.thy;
   597 
   598 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   599 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   600 lift.induct_tac, always use UU instead of Undef;
   601 
   602 * HOLCF/IMP: updated and converted to new-style theory;
   603 
   604 
   605 *** ZF ***
   606 
   607 * Isar: proper integration of logic-specific tools and packages,
   608 including theory commands '(co)inductive', '(co)datatype',
   609 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   610 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   611 
   612 * theory Main no longer includes AC; for the Axiom of Choice, base
   613 your theory on Main_ZFC;
   614 
   615 * the integer library now covers quotients and remainders, with many
   616 laws relating division to addition, multiplication, etc.;
   617 
   618 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   619 typeless version of the formalism;
   620 
   621 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   622 format;
   623 
   624 * ZF/Induct: new directory for examples of inductive definitions,
   625 including theory Multiset for multiset orderings; converted to
   626 new-style theory format;
   627 
   628 * ZF: many new theorems about lists, ordinals, etc.;
   629 
   630 
   631 *** General ***
   632 
   633 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   634 variable proof controls level of detail: 0 = no proofs (only oracle
   635 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   636 also ref manual for further ML interfaces;
   637 
   638 * Pure/axclass: removed obsolete ML interface
   639 goal_subclass/goal_arity;
   640 
   641 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   642 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   643 separate tokens, so expressions involving minus need to be spaced
   644 properly;
   645 
   646 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   647 rather than "infixl" or "infixr";
   648 
   649 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   650 sort constraint specifications in type inference; e.g. "x::_::foo"
   651 ensures that the type of "x" is of sort "foo" (but not necessarily a
   652 type variable);
   653 
   654 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   655 control output of nested => (types); the default behavior is
   656 "type_brackets";
   657 
   658 * Pure/syntax: builtin parse translation for "_constify" turns valued
   659 tokens into AST constants;
   660 
   661 * Pure/syntax: prefer later declarations of translations and print
   662 translation functions; potential INCOMPATIBILITY: need to reverse
   663 multiple declarations for same syntax element constant;
   664 
   665 * Pure/show_hyps reset by default (in accordance to existing Isar
   666 practice);
   667 
   668 * Provers/classical: renamed addaltern to addafter, addSaltern to
   669 addSafter;
   670 
   671 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   672 as well;
   673 
   674 * system: tested support for MacOS X; should be able to get Isabelle +
   675 Proof General to work in a plain Terminal after installing Poly/ML
   676 (e.g. from the Isabelle distribution area) and GNU bash alone
   677 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   678 support requires further installations, e.g. from
   679 http://fink.sourceforge.net/);
   680 
   681 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   682 
   683 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   684 of 40 MB), cf. ML_OPTIONS;
   685 
   686 * system: Proof General keywords specification is now part of the
   687 Isabelle distribution (see etc/isar-keywords.el);
   688 
   689 * system: support for persistent Proof General sessions (refrain from
   690 outdating all loaded theories on startup); user may create writable
   691 logic images like this: ``isabelle -q HOL Test'';
   692 
   693 * system: smart selection of Isabelle process versus Isabelle
   694 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   695 run both "isabelle" and "Isabelle" even if file names are badly
   696 damaged (executable inspects the case of the first letter of its own
   697 name); added separate "isabelle-process" and "isabelle-interface";
   698 
   699 * system: refrain from any attempt at filtering input streams; no
   700 longer support ``8bit'' encoding of old isabelle font, instead proper
   701 iso-latin characters may now be used; the related isatools
   702 "symbolinput" and "nonascii" have disappeared as well;
   703 
   704 * system: removed old "xterm" interface (the print modes "xterm" and
   705 "xterm_color" are still available for direct use in a suitable
   706 terminal);
   707 
   708 
   709 
   710 New in Isabelle99-2 (February 2001)
   711 -----------------------------------
   712 
   713 *** Overview of INCOMPATIBILITIES ***
   714 
   715 * HOL: please note that theories in the Library and elsewhere often use the
   716 new-style (Isar) format; to refer to their theorems in an ML script you must
   717 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   718 
   719 * HOL: inductive package no longer splits induction rule aggressively,
   720 but only as far as specified by the introductions given; the old
   721 format may be recovered via ML function complete_split_rule or attribute
   722 'split_rule (complete)';
   723 
   724 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   725 gfp_Tarski to gfp_unfold;
   726 
   727 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   728 
   729 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   730 relation); infix "^^" has been renamed "``"; infix "``" has been
   731 renamed "`"; "univalent" has been renamed "single_valued";
   732 
   733 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   734 operation;
   735 
   736 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   737 
   738 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   739 
   740 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   741 consequence, it is no longer monotonic wrt. the local goal context
   742 (which is now passed through the inductive cases);
   743 
   744 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   745 \<gg> to \<ggreater>;
   746 
   747 
   748 *** Document preparation ***
   749 
   750 * \isabellestyle{NAME} selects version of Isabelle output (currently
   751 available: are "it" for near math-mode best-style output, "sl" for
   752 slanted text style, and "tt" for plain type-writer; if no
   753 \isabellestyle command is given, output is according to slanted
   754 type-writer);
   755 
   756 * support sub/super scripts (for single symbols only), input syntax is
   757 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   758 
   759 * some more standard symbols; see Appendix A of the system manual for
   760 the complete list of symbols defined in isabellesym.sty;
   761 
   762 * improved isabelle style files; more abstract symbol implementation
   763 (should now use \isamath{...} and \isatext{...} in custom symbol
   764 definitions);
   765 
   766 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   767 state; Note that presentation of goal states does not conform to
   768 actual human-readable proof documents.  Please do not include goal
   769 states into document output unless you really know what you are doing!
   770 
   771 * proper indentation of antiquoted output with proportional LaTeX
   772 fonts;
   773 
   774 * no_document ML operator temporarily disables LaTeX document
   775 generation;
   776 
   777 * isatool unsymbolize tunes sources for plain ASCII communication;
   778 
   779 
   780 *** Isar ***
   781 
   782 * Pure: Isar now suffers initial goal statements to contain unbound
   783 schematic variables (this does not conform to actual readable proof
   784 documents, due to unpredictable outcome and non-compositional proof
   785 checking); users who know what they are doing may use schematic goals
   786 for Prolog-style synthesis of proven results;
   787 
   788 * Pure: assumption method (an implicit finishing) now handles actual
   789 rules as well;
   790 
   791 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   792 initial goal, declare "that" only as Pure intro (only for single
   793 steps); the "that" rule assumption may now be involved in implicit
   794 finishing, thus ".." becomes a feasible for trivial obtains;
   795 
   796 * Pure: default proof step now includes 'intro_classes'; thus trivial
   797 instance proofs may be performed by "..";
   798 
   799 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   800 statements as well;
   801 
   802 * Pure: more robust selection of calculational rules;
   803 
   804 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   805 rule (as well as the assumption rule);
   806 
   807 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   808 lemmas, using the graph browser tool;
   809 
   810 * Pure: predict failure of "show" in interactive mode;
   811 
   812 * Pure: 'thms_containing' now takes actual terms as arguments;
   813 
   814 * HOL: improved method 'induct' --- now handles non-atomic goals
   815 (potential INCOMPATIBILITY); tuned error handling;
   816 
   817 * HOL: cases and induct rules now provide explicit hints about the
   818 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   819 any remaining facts are inserted into the goal verbatim;
   820 
   821 * HOL: local contexts (aka cases) may now contain term bindings as
   822 well; the 'cases' and 'induct' methods new provide a ?case binding for
   823 the result to be shown in each case;
   824 
   825 * HOL: added 'recdef_tc' command;
   826 
   827 * isatool convert assists in eliminating legacy ML scripts;
   828 
   829 
   830 *** HOL ***
   831 
   832 * HOL/Library: a collection of generic theories to be used together
   833 with main HOL; the theory loader path already includes this directory
   834 by default; the following existing theories have been moved here:
   835 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   836 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   837 
   838 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   839 modelling and verification task performed in Isabelle/HOL +
   840 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   841 
   842 * HOL/Algebra: special summation operator SUM no longer exists, it has
   843 been replaced by setsum; infix 'assoc' now has priority 50 (like
   844 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   845 'domain', this makes the theory consistent with mathematical
   846 literature;
   847 
   848 * HOL basics: added overloaded operations "inverse" and "divide"
   849 (infix "/"), syntax for generic "abs" operation, generic summation
   850 operator \<Sum>;
   851 
   852 * HOL/typedef: simplified package, provide more useful rules (see also
   853 HOL/subset.thy);
   854 
   855 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   856 now expressed as a proper nested rule (old-style tactic scripts may
   857 require atomize_strip_tac to cope with non-atomic premises);
   858 
   859 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   860 to "split_conv" (old name still available for compatibility);
   861 
   862 * HOL: improved concrete syntax for strings (e.g. allows translation
   863 rules with string literals);
   864 
   865 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   866  and Fleuriot's mechanization of analysis, including the transcendental
   867  functions for the reals;
   868 
   869 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   870 
   871 
   872 *** CTT ***
   873 
   874 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   875 "lam" is displayed as TWO lambda-symbols
   876 
   877 * CTT: theory Main now available, containing everything (that is, Bool
   878 and Arith);
   879 
   880 
   881 *** General ***
   882 
   883 * Pure: the Simplifier has been implemented properly as a derived rule
   884 outside of the actual kernel (at last!); the overall performance
   885 penalty in practical applications is about 50%, while reliability of
   886 the Isabelle inference kernel has been greatly improved;
   887 
   888 * print modes "brackets" and "no_brackets" control output of nested =>
   889 (types) and ==> (props); the default behaviour is "brackets";
   890 
   891 * Provers: fast_tac (and friends) now handle actual object-logic rules
   892 as assumptions as well;
   893 
   894 * system: support Poly/ML 4.0;
   895 
   896 * system: isatool install handles KDE version 1 or 2;
   897 
   898 
   899 
   900 New in Isabelle99-1 (October 2000)
   901 ----------------------------------
   902 
   903 *** Overview of INCOMPATIBILITIES ***
   904 
   905 * HOL: simplification of natural numbers is much changed; to partly
   906 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   907 issue the following ML commands:
   908 
   909   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   910   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   911 
   912 * HOL: simplification no longer dives into case-expressions; this is
   913 controlled by "t.weak_case_cong" for each datatype t;
   914 
   915 * HOL: nat_less_induct renamed to less_induct;
   916 
   917 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   918 fixsome to patch .thy and .ML sources automatically;
   919 
   920   select_equality  -> some_equality
   921   select_eq_Ex     -> some_eq_ex
   922   selectI2EX       -> someI2_ex
   923   selectI2         -> someI2
   924   selectI          -> someI
   925   select1_equality -> some1_equality
   926   Eps_sym_eq       -> some_sym_eq_trivial
   927   Eps_eq           -> some_eq_trivial
   928 
   929 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   930 
   931 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   932 instead);
   933 
   934 * HOL: the recursion equations generated by 'recdef' are now called
   935 f.simps instead of f.rules;
   936 
   937 * HOL: qed_spec_mp now also handles bounded ALL as well;
   938 
   939 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   940 sometimes be needed;
   941 
   942 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   943 
   944 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   945 
   946 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   947 product is now "<*>" instead of "Times"; the lexicographic product is
   948 now "<*lex*>" instead of "**";
   949 
   950 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   951 of main HOL, but was unused); better use HOL's datatype package;
   952 
   953 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   954 the old syntax may be recovered as follows:
   955 
   956   syntax (symbols)
   957     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   958       (infixl "\\<oplus>" 100)
   959 
   960 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   961 
   962 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   963 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   964 internally;
   965 
   966 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   967 changed from A/r to A//r;
   968 
   969 * ZF: new treatment of arithmetic (nat & int) may break some old
   970 proofs;
   971 
   972 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   973 rulify -> rule_format, elimify -> elim_format, ...);
   974 
   975 * Isar/Provers: intro/elim/dest attributes changed; renamed
   976 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   977 should have to change intro!! to intro? only); replaced "delrule" by
   978 "rule del";
   979 
   980 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   981 
   982 * Provers: strengthened force_tac by using new first_best_tac;
   983 
   984 * LaTeX document preparation: several changes of isabelle.sty (see
   985 lib/texinputs);
   986 
   987 
   988 *** Document preparation ***
   989 
   990 * formal comments (text blocks etc.) in new-style theories may now
   991 contain antiquotations of thm/prop/term/typ/text to be presented
   992 according to latex print mode; concrete syntax is like this:
   993 @{term[show_types] "f(x) = a + x"};
   994 
   995 * isatool mkdir provides easy setup of Isabelle session directories,
   996 including proper document sources;
   997 
   998 * generated LaTeX sources are now deleted after successful run
   999 (isatool document -c); may retain a copy somewhere else via -D option
  1000 of isatool usedir;
  1001 
  1002 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1003 style files, achieving self-contained LaTeX sources and simplifying
  1004 LaTeX debugging;
  1005 
  1006 * old-style theories now produce (crude) LaTeX output as well;
  1007 
  1008 * browser info session directories are now self-contained (may be put
  1009 on WWW server seperately); improved graphs of nested sessions; removed
  1010 graph for 'all sessions';
  1011 
  1012 * several improvements in isabelle style files; \isabellestyle{it}
  1013 produces fake math mode output; \isamarkupheader is now \section by
  1014 default; see lib/texinputs/isabelle.sty etc.;
  1015 
  1016 
  1017 *** Isar ***
  1018 
  1019 * Isar/Pure: local results and corresponding term bindings are now
  1020 subject to Hindley-Milner polymorphism (similar to ML); this
  1021 accommodates incremental type-inference very nicely;
  1022 
  1023 * Isar/Pure: new derived language element 'obtain' supports
  1024 generalized existence reasoning;
  1025 
  1026 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1027 support accumulation of results, without applying any rules yet;
  1028 useful to collect intermediate results without explicit name
  1029 references, and for use with transitivity rules with more than 2
  1030 premises;
  1031 
  1032 * Isar/Pure: scalable support for case-analysis type proofs: new
  1033 'case' language element refers to local contexts symbolically, as
  1034 produced by certain proof methods; internally, case names are attached
  1035 to theorems as "tags";
  1036 
  1037 * Isar/Pure: theory command 'hide' removes declarations from
  1038 class/type/const name spaces;
  1039 
  1040 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1041 indicate potential overloading;
  1042 
  1043 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1044 
  1045 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1046 "{a,b,c}" instead of {a,b,c};
  1047 
  1048 * Isar/Pure now provides its own version of intro/elim/dest
  1049 attributes; useful for building new logics, but beware of confusion
  1050 with the version in Provers/classical;
  1051 
  1052 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1053 case name 'antecedent';
  1054 
  1055 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1056 to the current context is now done automatically);
  1057 
  1058 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1059 for definining proof methods in ML;
  1060 
  1061 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1062 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1063 most cases, one should have to change intro!! to intro? only);
  1064 replaced "delrule" by "rule del";
  1065 
  1066 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1067 'symmetric' attribute (the latter supercedes [RS sym]);
  1068 
  1069 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1070 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1071 well (including splits);
  1072 
  1073 * Isar/Provers: Simplifier and Classical methods now support all kind
  1074 of modifiers used in the past, including 'cong', 'iff', etc.
  1075 
  1076 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1077 of Simplifier and Classical reasoner);
  1078 
  1079 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1080 now support named cases; major packages (inductive, datatype, primrec,
  1081 recdef) support case names and properly name parameters;
  1082 
  1083 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1084 monotonicity conditions are extracted to be proven at end of
  1085 calculations;
  1086 
  1087 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1088 method anyway;
  1089 
  1090 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1091 split_if split_if_asm; datatype package provides theorems foo.splits =
  1092 foo.split foo.split_asm for each datatype;
  1093 
  1094 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1095 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1096 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1097 use "(cases (simplified))" method in proper proof texts);
  1098 
  1099 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1100 
  1101 * Isar: names of theorems etc. may be natural numbers as well;
  1102 
  1103 * Isar: 'pr' command: optional arguments for goals_limit and
  1104 ProofContext.prems_limit; no longer prints theory contexts, but only
  1105 proof states;
  1106 
  1107 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1108 additional print modes to be specified; e.g. "pr(latex)" will print
  1109 proof state according to the Isabelle LaTeX style;
  1110 
  1111 * Isar: improved support for emulating tactic scripts, including proof
  1112 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1113 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1114 (for HOL datatypes);
  1115 
  1116 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1117 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1118 'proof method scripts' have to be in depth-first order;
  1119 
  1120 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1121 
  1122 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1123 should instead use individual commands for printing items
  1124 (print_commands, print_methods etc.);
  1125 
  1126 * Isar: added 'nothing' --- the empty list of theorems;
  1127 
  1128 
  1129 *** HOL ***
  1130 
  1131 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1132 corresponding virtual machine and a specification of its bytecode
  1133 verifier and a lightweight bytecode verifier, including proofs of
  1134 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1135 Cornelia Pusch (see also the homepage of project Bali at
  1136 http://isabelle.in.tum.de/Bali/);
  1137 
  1138 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1139 Clemens Ballarin;
  1140 
  1141 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1142 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1143 Rasmussen;
  1144 
  1145 * HOL/Lattice: fundamental concepts of lattice theory and order
  1146 structures, including duals, properties of bounds versus algebraic
  1147 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1148 Theorem for complete lattices etc.; may also serve as a demonstration
  1149 for abstract algebraic reasoning using axiomatic type classes, and
  1150 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1151 
  1152 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1153 von Oheimb;
  1154 
  1155 * HOL/IMPP: extension of IMP with local variables and mutually
  1156 recursive procedures, by David von Oheimb;
  1157 
  1158 * HOL/Lambda: converted into new-style theory and document;
  1159 
  1160 * HOL/ex/Multiquote: example of multiple nested quotations and
  1161 anti-quotations -- basically a generalized version of de-Bruijn
  1162 representation; very useful in avoiding lifting of operations;
  1163 
  1164 * HOL/record: added general record equality rule to simpset; fixed
  1165 select-update simplification procedure to handle extended records as
  1166 well; admit "r" as field name;
  1167 
  1168 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1169 other numeric types and also as the identity of groups, rings, etc.;
  1170 
  1171 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1172 Types nat and int belong to this axclass;
  1173 
  1174 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1175    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1176    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1177   two terms #m*u and #n*u are replaced by #(m+n)*u
  1178     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1179   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1180     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1181 
  1182 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1183 powerful prover for predicate logic but knows nothing of clasets; see
  1184 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1185 
  1186 * HOL: new version of "case_tac" subsumes both boolean case split and
  1187 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1188 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1189 
  1190 * HOL: simplification no longer dives into case-expressions: only the
  1191 selector expression is simplified, but not the remaining arms; to
  1192 enable full simplification of case-expressions for datatype t, you may
  1193 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1194 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1195 
  1196 * HOL/recdef: the recursion equations generated by 'recdef' for
  1197 function 'f' are now called f.simps instead of f.rules; if all
  1198 termination conditions are proved automatically, these simplification
  1199 rules are added to the simpset, as in primrec; rules may be named
  1200 individually as well, resulting in a separate list of theorems for
  1201 each equation;
  1202 
  1203 * HOL/While is a new theory that provides a while-combinator. It
  1204 permits the definition of tail-recursive functions without the
  1205 provision of a termination measure. The latter is necessary once the
  1206 invariant proof rule for while is applied.
  1207 
  1208 * HOL: new (overloaded) notation for the set of elements below/above
  1209 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1210 
  1211 * HOL: theorems impI, allI, ballI bound as "strip";
  1212 
  1213 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1214 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1215 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1216 
  1217 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1218 
  1219 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1220 main HOL, but was unused);
  1221 
  1222 * HOL: fewer consts declared as global (e.g. have to refer to
  1223 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1224 
  1225 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1226 in case of overlap with user translations (e.g. judgements over
  1227 tuples); (note that the underlying logical represenation is still
  1228 bogus);
  1229 
  1230 
  1231 *** ZF ***
  1232 
  1233 * ZF: simplification automatically cancels common terms in arithmetic
  1234 expressions over nat and int;
  1235 
  1236 * ZF: new treatment of nat to minimize type-checking: all operators
  1237 coerce their operands to a natural number using the function natify,
  1238 making the algebraic laws unconditional;
  1239 
  1240 * ZF: as above, for int: operators coerce their operands to an integer
  1241 using the function intify;
  1242 
  1243 * ZF: the integer library now contains many of the usual laws for the
  1244 orderings, including $<=, and monotonicity laws for $+ and $*;
  1245 
  1246 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1247 simplification;
  1248 
  1249 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1250 to the simplifier and classical reasoner simultaneously;
  1251 
  1252 
  1253 *** General ***
  1254 
  1255 * Provers: blast_tac now handles actual object-logic rules as
  1256 assumptions; note that auto_tac uses blast_tac internally as well;
  1257 
  1258 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1259 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1260 
  1261 * Provers: delrules now handles destruct rules as well (no longer need
  1262 explicit make_elim);
  1263 
  1264 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1265   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1266 use instead the strong form,
  1267   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1268 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1269 from destruct-rules;
  1270 
  1271 * Provers: Simplifier.easy_setup provides a fast path to basic
  1272 Simplifier setup for new object-logics;
  1273 
  1274 * Pure: AST translation rules no longer require constant head on LHS;
  1275 
  1276 * Pure: improved name spaces: ambiguous output is qualified; support
  1277 for hiding of names;
  1278 
  1279 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1280 XSYMBOL_HOME; no longer need to do manual configuration in most
  1281 situations;
  1282 
  1283 * system: compression of ML heaps images may now be controlled via -c
  1284 option of isabelle and isatool usedir (currently only observed by
  1285 Poly/ML);
  1286 
  1287 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1288 useful for remote X11);
  1289 
  1290 * system: provide TAGS file for Isabelle sources;
  1291 
  1292 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1293 order;
  1294 
  1295 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1296 timing flag supersedes proof_timing and Toplevel.trace;
  1297 
  1298 * ML: new combinators |>> and |>>> for incremental transformations
  1299 with secondary results (e.g. certain theory extensions):
  1300 
  1301 * ML: PureThy.add_defs gets additional argument to indicate potential
  1302 overloading (usually false);
  1303 
  1304 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1305 results;
  1306 
  1307 
  1308 
  1309 New in Isabelle99 (October 1999)
  1310 --------------------------------
  1311 
  1312 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1313 
  1314 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1315 are no longer simplified.  (This allows the simplifier to unfold recursive
  1316 functional programs.)  To restore the old behaviour, declare
  1317 
  1318     Delcongs [if_weak_cong];
  1319 
  1320 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1321 complement;
  1322 
  1323 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1324 
  1325 * HOL/datatype: mutual_induct_tac no longer exists --
  1326   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1327 
  1328 * HOL/typedef: fixed type inference for representing set; type
  1329 arguments now have to occur explicitly on the rhs as type constraints;
  1330 
  1331 * ZF: The con_defs part of an inductive definition may no longer refer
  1332 to constants declared in the same theory;
  1333 
  1334 * HOL, ZF: the function mk_cases, generated by the inductive
  1335 definition package, has lost an argument.  To simplify its result, it
  1336 uses the default simpset instead of a supplied list of theorems.
  1337 
  1338 * HOL/List: the constructors of type list are now Nil and Cons;
  1339 
  1340 * Simplifier: the type of the infix ML functions
  1341         setSSolver addSSolver setSolver addSolver
  1342 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1343 for packaging solvers. A solver is created via
  1344         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1345 where the string argument is only a comment.
  1346 
  1347 
  1348 *** Proof tools ***
  1349 
  1350 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1351 decision procedure for linear arithmetic. Currently it is used for
  1352 types `nat', `int', and `real' in HOL (see below); it can, should and
  1353 will be instantiated for other types and logics as well.
  1354 
  1355 * The simplifier now accepts rewrite rules with flexible heads, eg
  1356      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1357   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1358   matching.
  1359 
  1360 
  1361 *** General ***
  1362 
  1363 * New Isabelle/Isar subsystem provides an alternative to traditional
  1364 tactical theorem proving; together with the ProofGeneral/isar user
  1365 interface it offers an interactive environment for developing human
  1366 readable proof documents (Isar == Intelligible semi-automated
  1367 reasoning); for further information see isatool doc isar-ref,
  1368 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1369 
  1370 * improved and simplified presentation of theories: better HTML markup
  1371 (including colors), graph views in several sizes; isatool usedir now
  1372 provides a proper interface for user theories (via -P option); actual
  1373 document preparation based on (PDF)LaTeX is available as well (for
  1374 new-style theories only); see isatool doc system for more information;
  1375 
  1376 * native support for Proof General, both for classic Isabelle and
  1377 Isabelle/Isar;
  1378 
  1379 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1380 using the graph browser tool;
  1381 
  1382 * Isabelle manuals now also available as PDF;
  1383 
  1384 * theory loader rewritten from scratch (may not be fully
  1385 bug-compatible); old loadpath variable has been replaced by show_path,
  1386 add_path, del_path, reset_path functions; new operations such as
  1387 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1388 isatool doc ref);
  1389 
  1390 * improved isatool install: option -k creates KDE application icon,
  1391 option -p DIR installs standalone binaries;
  1392 
  1393 * added ML_PLATFORM setting (useful for cross-platform installations);
  1394 more robust handling of platform specific ML images for SML/NJ;
  1395 
  1396 * the settings environment is now statically scoped, i.e. it is never
  1397 created again in sub-processes invoked from isabelle, isatool, or
  1398 Isabelle;
  1399 
  1400 * path element specification '~~' refers to '$ISABELLE_HOME';
  1401 
  1402 * in locales, the "assumes" and "defines" parts may be omitted if
  1403 empty;
  1404 
  1405 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1406 long arrows);
  1407 
  1408 * new print_mode "HTML";
  1409 
  1410 * new flag show_tags controls display of tags of theorems (which are
  1411 basically just comments that may be attached by some tools);
  1412 
  1413 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1414 mode and goal output format:
  1415 
  1416 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1417 244c244
  1418 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1419 ---
  1420 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1421 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1422 181c181
  1423 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1424 ---
  1425 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1426 
  1427 * function bind_thms stores lists of theorems (cf. bind_thm);
  1428 
  1429 * new shorthand tactics ftac, eatac, datac, fatac;
  1430 
  1431 * qed (and friends) now accept "" as result name; in that case the
  1432 theorem is not stored, but proper checks and presentation of the
  1433 result still apply;
  1434 
  1435 * theorem database now also indexes constants "Trueprop", "all",
  1436 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1437 
  1438 
  1439 *** HOL ***
  1440 
  1441 ** HOL arithmetic **
  1442 
  1443 * There are now decision procedures for linear arithmetic over nat and
  1444 int:
  1445 
  1446 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1447 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1448 are treated as atomic; subformulae not involving type `nat' or `int'
  1449 are ignored; quantified subformulae are ignored unless they are
  1450 positive universal or negative existential. The tactic has to be
  1451 invoked by hand and can be a little bit slow. In particular, the
  1452 running time is exponential in the number of occurrences of `min' and
  1453 `max', and `-' on `nat'.
  1454 
  1455 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1456 (negated) (in)equalities among the premises and the conclusion into
  1457 account (i.e. no compound formulae) and does not know about `min' and
  1458 `max', and `-' on `nat'. It is fast and is used automatically by the
  1459 simplifier.
  1460 
  1461 NB: At the moment, these decision procedures do not cope with mixed
  1462 nat/int formulae where the two parts interact, such as `m < n ==>
  1463 int(m) < int(n)'.
  1464 
  1465 * HOL/Numeral provides a generic theory of numerals (encoded
  1466 efficiently as bit strings); setup for types nat/int/real is in place;
  1467 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1468 int, existing theories and proof scripts may require a few additional
  1469 type constraints;
  1470 
  1471 * integer division and remainder can now be performed on constant
  1472 arguments;
  1473 
  1474 * many properties of integer multiplication, division and remainder
  1475 are now available;
  1476 
  1477 * An interface to the Stanford Validity Checker (SVC) is available through the
  1478 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1479 are proved automatically.  SVC must be installed separately, and its results
  1480 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1481 invocation of the underlying oracle).  For SVC see
  1482   http://verify.stanford.edu/SVC
  1483 
  1484 * IsaMakefile: the HOL-Real target now builds an actual image;
  1485 
  1486 
  1487 ** HOL misc **
  1488 
  1489 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1490 (in Isabelle/Isar) -- by Gertrud Bauer;
  1491 
  1492 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1493 analysis for assembly languages with subtypes;
  1494 
  1495 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1496 -- avoids syntactic ambiguities and treats state, transition, and
  1497 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1498 changed syntax and (many) tactics;
  1499 
  1500 * HOL/inductive: Now also handles more general introduction rules such
  1501   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1502   theorems are now maintained within the theory (maintained via the
  1503   "mono" attribute);
  1504 
  1505 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1506   (using function types) such as
  1507 
  1508   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1509 
  1510 * HOL/record: record_simproc (part of the default simpset) takes care
  1511 of selectors applied to updated records; record_split_tac is no longer
  1512 part of the default claset; update_defs may now be removed from the
  1513 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1514 
  1515   claset_ref () := claset() addSWrapper record_split_wrapper;
  1516   Delsimprocs [record_simproc]
  1517 
  1518 * HOL/typedef: fixed type inference for representing set; type
  1519 arguments now have to occur explicitly on the rhs as type constraints;
  1520 
  1521 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1522 names rather than an ML expression;
  1523 
  1524 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1525 supplied later.  Program schemes can be defined, such as
  1526     "While B C s = (if B s then While B C (C s) else s)"
  1527 where the well-founded relation can be chosen after B and C have been given.
  1528 
  1529 * HOL/List: the constructors of type list are now Nil and Cons;
  1530 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1531 course, ML tools referring to List.list.op # etc. have to be adapted;
  1532 
  1533 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1534 disabled by default; run isabelle with option -m HOL to get back to
  1535 the original Gordon/HOL-style output;
  1536 
  1537 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1538 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1539 
  1540 * HOL basic syntax simplified (more orthogonal): all variants of
  1541 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1542 Eps operator is provided as well: "SOME x. P[x]";
  1543 
  1544 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1545 
  1546 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1547 thus available for user theories;
  1548 
  1549 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1550 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1551 time;
  1552 
  1553 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1554 several times and then mp;
  1555 
  1556 
  1557 *** LK ***
  1558 
  1559 * the notation <<...>> is now available as a notation for sequences of
  1560 formulas;
  1561 
  1562 * the simplifier is now installed
  1563 
  1564 * the axiom system has been generalized (thanks to Soren Heilmann)
  1565 
  1566 * the classical reasoner now has a default rule database
  1567 
  1568 
  1569 *** ZF ***
  1570 
  1571 * new primrec section allows primitive recursive functions to be given
  1572 directly (as in HOL) over datatypes and the natural numbers;
  1573 
  1574 * new tactics induct_tac and exhaust_tac for induction (or case
  1575 analysis) over datatypes and the natural numbers;
  1576 
  1577 * the datatype declaration of type T now defines the recursor T_rec;
  1578 
  1579 * simplification automatically does freeness reasoning for datatype
  1580 constructors;
  1581 
  1582 * automatic type-inference, with AddTCs command to insert new
  1583 type-checking rules;
  1584 
  1585 * datatype introduction rules are now added as Safe Introduction rules
  1586 to the claset;
  1587 
  1588 * the syntax "if P then x else y" is now available in addition to
  1589 if(P,x,y);
  1590 
  1591 
  1592 *** Internal programming interfaces ***
  1593 
  1594 * tuned simplifier trace output; new flag debug_simp;
  1595 
  1596 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1597 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1598 
  1599 * AxClass.axclass_tac lost the theory argument;
  1600 
  1601 * tuned current_goals_markers semantics: begin / end goal avoids
  1602 printing empty lines;
  1603 
  1604 * removed prs and prs_fn hook, which was broken because it did not
  1605 include \n in its semantics, forcing writeln to add one
  1606 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1607 string -> unit if you really want to output text without newline;
  1608 
  1609 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1610 plain output, interface builders may have to enable 'isabelle_font'
  1611 mode to get Isabelle font glyphs as before;
  1612 
  1613 * refined token_translation interface; INCOMPATIBILITY: output length
  1614 now of type real instead of int;
  1615 
  1616 * theory loader actions may be traced via new ThyInfo.add_hook
  1617 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1618 your own database of information attached to *whole* theories -- as
  1619 opposed to intra-theory data slots offered via TheoryDataFun;
  1620 
  1621 * proper handling of dangling sort hypotheses (at last!);
  1622 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1623 extra sort hypotheses that can be witnessed from the type signature;
  1624 the force_strip_shyps flag is gone, any remaining shyps are simply
  1625 left in the theorem (with a warning issued by strip_shyps_warning);
  1626 
  1627 
  1628 
  1629 New in Isabelle98-1 (October 1998)
  1630 ----------------------------------
  1631 
  1632 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1633 
  1634 * several changes of automated proof tools;
  1635 
  1636 * HOL: major changes to the inductive and datatype packages, including
  1637 some minor incompatibilities of theory syntax;
  1638 
  1639 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1640 called `inj_on';
  1641 
  1642 * HOL: removed duplicate thms in Arith:
  1643   less_imp_add_less  should be replaced by  trans_less_add1
  1644   le_imp_add_le      should be replaced by  trans_le_add1
  1645 
  1646 * HOL: unary minus is now overloaded (new type constraints may be
  1647 required);
  1648 
  1649 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1650 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1651 now taken as an integer constant.
  1652 
  1653 * Pure: ML function 'theory_of' renamed to 'theory';
  1654 
  1655 
  1656 *** Proof tools ***
  1657 
  1658 * Simplifier:
  1659   1. Asm_full_simp_tac is now more aggressive.
  1660      1. It will sometimes reorient premises if that increases their power to
  1661         simplify.
  1662      2. It does no longer proceed strictly from left to right but may also
  1663         rotate premises to achieve further simplification.
  1664      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1665      old Asm_full_simp_tac in that it does not rotate premises.
  1666   2. The simplifier now knows a little bit about nat-arithmetic.
  1667 
  1668 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1669 allows for selected deletion of wrappers, by introduction of names for
  1670 wrapper functionals.  This implies that addbefore, addSbefore,
  1671 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1672 and that adding two tactics with the same name overwrites the first
  1673 one (emitting a warning).
  1674   type wrapper = (int -> tactic) -> (int -> tactic)
  1675   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1676   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1677   delWrapper, delSWrapper: claset *  string            -> claset
  1678   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1679 
  1680 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1681 semantics; addbefore now affects only the unsafe part of step_tac
  1682 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1683 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1684 by Force_tac;
  1685 
  1686 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1687 compWrapper; added safe wrapper (and access functions for it);
  1688 
  1689 * HOL/split_all_tac is now much faster and fails if there is nothing
  1690 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1691 and the names of the automatically generated variables have changed.
  1692 split_all_tac has moved within claset() from unsafe wrappers to safe
  1693 wrappers, which means that !!-bound variables are split much more
  1694 aggressively, and safe_tac and clarify_tac now split such variables.
  1695 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1696 Note: the same holds for record_split_tac, which does the job of
  1697 split_all_tac for record fields.
  1698 
  1699 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1700 permanently to the default simpset using Addsplits just like
  1701 Addsimps. They can be removed via Delsplits just like
  1702 Delsimps. Lower-case versions are also available.
  1703 
  1704 * HOL/Simplifier: The rule split_if is now part of the default
  1705 simpset. This means that the simplifier will eliminate all occurrences
  1706 of if-then-else in the conclusion of a goal. To prevent this, you can
  1707 either remove split_if completely from the default simpset by
  1708 `Delsplits [split_if]' or remove it in a specific call of the
  1709 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1710 other case splitting rules to/from the default simpset: every datatype
  1711 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1712 t is the name of the datatype).
  1713 
  1714 * Classical reasoner / Simplifier combination: new force_tac (and
  1715 derivatives Force_tac, force) combines rewriting and classical
  1716 reasoning (and whatever other tools) similarly to auto_tac, but is
  1717 aimed to solve the given subgoal completely.
  1718 
  1719 
  1720 *** General ***
  1721 
  1722 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1723 and `goalw': the theory is no longer needed as an explicit argument -
  1724 the current theory context is used; assumptions are no longer returned
  1725 at the ML-level unless one of them starts with ==> or !!; it is
  1726 recommended to convert to these new commands using isatool fixgoal
  1727 (backup your sources first!);
  1728 
  1729 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1730 the current theory context, and 'theory' to lookup stored theories;
  1731 
  1732 * new theory section 'locale' for declaring constants, assumptions and
  1733 definitions that have local scope;
  1734 
  1735 * new theory section 'nonterminals' for purely syntactic types;
  1736 
  1737 * new theory section 'setup' for generic ML setup functions
  1738 (e.g. package initialization);
  1739 
  1740 * the distribution now includes Isabelle icons: see
  1741 lib/logo/isabelle-{small,tiny}.xpm;
  1742 
  1743 * isatool install - install binaries with absolute references to
  1744 ISABELLE_HOME/bin;
  1745 
  1746 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1747 
  1748 * print mode 'emacs' reserved for Isamode;
  1749 
  1750 * support multiple print (ast) translations per constant name;
  1751 
  1752 * theorems involving oracles are now printed with a suffixed [!];
  1753 
  1754 
  1755 *** HOL ***
  1756 
  1757 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1758 
  1759 * HOL/inductive package reorganized and improved: now supports mutual
  1760 definitions such as
  1761 
  1762   inductive EVEN ODD
  1763     intrs
  1764       null "0 : EVEN"
  1765       oddI "n : EVEN ==> Suc n : ODD"
  1766       evenI "n : ODD ==> Suc n : EVEN"
  1767 
  1768 new theorem list "elims" contains an elimination rule for each of the
  1769 recursive sets; inductive definitions now handle disjunctive premises
  1770 correctly (also ZF);
  1771 
  1772 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1773 "mutual_induct" no longer exists - the induction rule is always
  1774 contained in "induct";
  1775 
  1776 
  1777 * HOL/datatype package re-implemented and greatly improved: now
  1778 supports mutually recursive datatypes such as
  1779 
  1780   datatype
  1781     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1782             | SUM ('a aexp) ('a aexp)
  1783             | DIFF ('a aexp) ('a aexp)
  1784             | NUM 'a
  1785   and
  1786     'a bexp = LESS ('a aexp) ('a aexp)
  1787             | AND ('a bexp) ('a bexp)
  1788             | OR ('a bexp) ('a bexp)
  1789 
  1790 as well as indirectly recursive datatypes such as
  1791 
  1792   datatype
  1793     ('a, 'b) term = Var 'a
  1794                   | App 'b ((('a, 'b) term) list)
  1795 
  1796 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1797 induction on mutually / indirectly recursive datatypes.
  1798 
  1799 Primrec equations are now stored in theory and can be accessed via
  1800 <function_name>.simps.
  1801 
  1802 INCOMPATIBILITIES:
  1803 
  1804   - Theories using datatypes must now have theory Datatype as an
  1805     ancestor.
  1806   - The specific <typename>.induct_tac no longer exists - use the
  1807     generic induct_tac instead.
  1808   - natE has been renamed to nat.exhaust - use exhaust_tac
  1809     instead of res_inst_tac ... natE. Note that the variable
  1810     names in nat.exhaust differ from the names in natE, this
  1811     may cause some "fragile" proofs to fail.
  1812   - The theorems split_<typename>_case and split_<typename>_case_asm
  1813     have been renamed to <typename>.split and <typename>.split_asm.
  1814   - Since default sorts of type variables are now handled correctly,
  1815     some datatype definitions may have to be annotated with explicit
  1816     sort constraints.
  1817   - Primrec definitions no longer require function name and type
  1818     of recursive argument.
  1819 
  1820 Consider using isatool fixdatatype to adapt your theories and proof
  1821 scripts to the new package (backup your sources first!).
  1822 
  1823 
  1824 * HOL/record package: considerably improved implementation; now
  1825 includes concrete syntax for record types, terms, updates; theorems
  1826 for surjective pairing and splitting !!-bound record variables; proof
  1827 support is as follows:
  1828 
  1829   1) standard conversions (selectors or updates applied to record
  1830 constructor terms) are part of the standard simpset;
  1831 
  1832   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1833 made part of standard simpset and claset via addIffs;
  1834 
  1835   3) a tactic for record field splitting (record_split_tac) is part of
  1836 the standard claset (addSWrapper);
  1837 
  1838 To get a better idea about these rules you may retrieve them via
  1839 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1840 the name of your record type.
  1841 
  1842 The split tactic 3) conceptually simplifies by the following rule:
  1843 
  1844   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1845 
  1846 Thus any record variable that is bound by meta-all will automatically
  1847 blow up into some record constructor term, consequently the
  1848 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1849 solve record problems automatically.
  1850 
  1851 
  1852 * reorganized the main HOL image: HOL/Integ and String loaded by
  1853 default; theory Main includes everything;
  1854 
  1855 * automatic simplification of integer sums and comparisons, using cancellation;
  1856 
  1857 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1858 
  1859 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1860 
  1861 * many new identities for unions, intersections, set difference, etc.;
  1862 
  1863 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1864 called split_if, split_split, split_sum_case and split_nat_case (to go
  1865 with add/delsplits);
  1866 
  1867 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1868 (?x::unit) = (); this is made part of the default simpset, which COULD
  1869 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1870 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1871 unit_abs_eta_conv is added in order to counter the effect of
  1872 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1873 %u.f();
  1874 
  1875 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1876 makes more sense);
  1877 
  1878 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1879   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1880   disjointness reasoning but breaking a few old proofs.
  1881 
  1882 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1883 to 'converse' from 'inverse' (for compatibility with ZF and some
  1884 literature);
  1885 
  1886 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1887 the well-founded relation;
  1888 
  1889 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1890     Compl A.  The "Compl" syntax remains available as input syntax for this
  1891     release ONLY.
  1892 
  1893 * HOL/Update: new theory of function updates:
  1894     f(a:=b) == %x. if x=a then b else f x
  1895 may also be iterated as in f(a:=b,c:=d,...);
  1896 
  1897 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1898 
  1899 * HOL/List:
  1900   - new function list_update written xs[i:=v] that updates the i-th
  1901     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1902   - new function `upt' written [i..j(] which generates the list
  1903     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1904     bound write [i..j], which is a shorthand for [i..j+1(].
  1905   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1906 
  1907 * HOL/Arith:
  1908   - removed 'pred' (predecessor) function;
  1909   - generalized some theorems about n-1;
  1910   - many new laws about "div" and "mod";
  1911   - new laws about greatest common divisors (see theory ex/Primes);
  1912 
  1913 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1914 instead of "inverse";
  1915 
  1916 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1917   of the multiset ordering;
  1918 
  1919 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1920   (not included by default);
  1921 
  1922 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1923 
  1924 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1925   programs, i.e. different program variables may have different types.
  1926 
  1927 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1928   [previously, this check worked only if the rewrite rule was unconditional]
  1929   Now rew can involve either definitions or equalities (either == or =).
  1930 
  1931 
  1932 *** ZF ***
  1933 
  1934 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1935   only the theorems proved on ZF.ML;
  1936 
  1937 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1938   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1939   disjointness reasoning but breaking a few old proofs.
  1940 
  1941 * ZF/Update: new theory of function updates
  1942     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1943   may also be iterated as in f(a:=b,c:=d,...);
  1944 
  1945 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1946 
  1947 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1948   [previously, this check worked only if the rewrite rule was unconditional]
  1949   Now rew can involve either definitions or equalities (either == or =).
  1950 
  1951 * case_tac provided for compatibility with HOL
  1952     (like the old excluded_middle_tac, but with subgoals swapped)
  1953 
  1954 
  1955 *** Internal programming interfaces ***
  1956 
  1957 * Pure: several new basic modules made available for general use, see
  1958 also src/Pure/README;
  1959 
  1960 * improved the theory data mechanism to support encapsulation (data
  1961 kind name replaced by private Object.kind, acting as authorization
  1962 key); new type-safe user interface via functor TheoryDataFun; generic
  1963 print_data function becomes basically useless;
  1964 
  1965 * removed global_names compatibility flag -- all theory declarations
  1966 are qualified by default;
  1967 
  1968 * module Pure/Syntax now offers quote / antiquote translation
  1969 functions (useful for Hoare logic etc. with implicit dependencies);
  1970 see HOL/ex/Antiquote for an example use;
  1971 
  1972 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1973 cterm -> thm;
  1974 
  1975 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1976 subgoal;
  1977 
  1978 * Display.print_goals function moved to Locale.print_goals;
  1979 
  1980 * standard print function for goals supports current_goals_markers
  1981 variable for marking begin of proof, end of proof, start of goal; the
  1982 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1983 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1984 for example;
  1985 
  1986 
  1987 
  1988 New in Isabelle98 (January 1998)
  1989 --------------------------------
  1990 
  1991 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1992 
  1993 * changed lexical syntax of terms / types: dots made part of long
  1994 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1995 
  1996 * simpset (and claset) reference variable replaced by functions
  1997 simpset / simpset_ref;
  1998 
  1999 * no longer supports theory aliases (via merge) and non-trivial
  2000 implicit merge of thms' signatures;
  2001 
  2002 * most internal names of constants changed due to qualified names;
  2003 
  2004 * changed Pure/Sequence interface (see Pure/seq.ML);
  2005 
  2006 
  2007 *** General Changes ***
  2008 
  2009 * hierachically structured name spaces (for consts, types, axms, thms
  2010 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2011 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2012 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2013 long_names for fully qualified output names; NOTE: ML programs
  2014 (special tactics, packages etc.) referring to internal names may have
  2015 to be adapted to cope with fully qualified names; in case of severe
  2016 backward campatibility problems try setting 'global_names' at compile
  2017 time to have enrything declared within a flat name space; one may also
  2018 fine tune name declarations in theories via the 'global' and 'local'
  2019 section;
  2020 
  2021 * reimplemented the implicit simpset and claset using the new anytype
  2022 data filed in signatures; references simpset:simpset ref etc. are
  2023 replaced by functions simpset:unit->simpset and
  2024 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2025 to patch your ML files accordingly;
  2026 
  2027 * HTML output now includes theory graph data for display with Java
  2028 applet or isatool browser; data generated automatically via isatool
  2029 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2030 
  2031 * defs may now be conditional; improved rewrite_goals_tac to handle
  2032 conditional equations;
  2033 
  2034 * defs now admits additional type arguments, using TYPE('a) syntax;
  2035 
  2036 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2037 creates a new theory node; implicit merge of thms' signatures is
  2038 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2039 transfer:theory->thm->thm in (rare) cases;
  2040 
  2041 * improved handling of draft signatures / theories; draft thms (and
  2042 ctyps, cterms) are automatically promoted to real ones;
  2043 
  2044 * slightly changed interfaces for oracles: admit many per theory, named
  2045 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2046 
  2047 * print_goals: optional output of const types (set show_consts and
  2048 show_types);
  2049 
  2050 * improved output of warnings (###) and errors (***);
  2051 
  2052 * subgoal_tac displays a warning if the new subgoal has type variables;
  2053 
  2054 * removed old README and Makefiles;
  2055 
  2056 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2057 
  2058 * removed obsolete init_pps and init_database;
  2059 
  2060 * deleted the obsolete tactical STATE, which was declared by
  2061     fun STATE tacfun st = tacfun st st;
  2062 
  2063 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2064 (which abbreviates $HOME);
  2065 
  2066 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2067 use isatool fixseq to adapt your ML programs (this works for fully
  2068 qualified references to the Sequence structure only!);
  2069 
  2070 * use_thy no longer requires writable current directory; it always
  2071 reloads .ML *and* .thy file, if either one is out of date;
  2072 
  2073 
  2074 *** Classical Reasoner ***
  2075 
  2076 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2077 tactics that use classical reasoning to simplify a subgoal without
  2078 splitting it into several subgoals;
  2079 
  2080 * Safe_tac: like safe_tac but uses the default claset;
  2081 
  2082 
  2083 *** Simplifier ***
  2084 
  2085 * added simplification meta rules:
  2086     (asm_)(full_)simplify: simpset -> thm -> thm;
  2087 
  2088 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2089 logics (again);
  2090 
  2091 * added prems argument to simplification procedures;
  2092 
  2093 * HOL, FOL, ZF: added infix function `addsplits':
  2094   instead of `<simpset> setloop (split_tac <thms>)'
  2095   you can simply write `<simpset> addsplits <thms>'
  2096 
  2097 
  2098 *** Syntax ***
  2099 
  2100 * TYPE('a) syntax for type reflection terms;
  2101 
  2102 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2103 
  2104 * pretty printer: changed order of mixfix annotation preference (again!);
  2105 
  2106 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2107 
  2108 
  2109 *** HOL ***
  2110 
  2111 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2112   with `addloop' of the simplifier to faciliate case splitting in premises.
  2113 
  2114 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2115 
  2116 * HOL/Auth: new protocol proofs including some for the Internet
  2117   protocol TLS;
  2118 
  2119 * HOL/Map: new theory of `maps' a la VDM;
  2120 
  2121 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2122 cancelling out common nat summands from =, <, <= (in)equalities, or
  2123 differences; simplification procedures nat_cancel_factor for
  2124 cancelling common factor from =, <, <= (in)equalities over natural
  2125 sums; nat_cancel contains both kinds of procedures, it is installed by
  2126 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2127 
  2128 * HOL/simplifier: terms of the form
  2129   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2130   are rewritten to
  2131   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2132   and those of the form
  2133   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2134   are rewritten to
  2135   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2136 
  2137 * HOL/datatype
  2138   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2139 
  2140   P(t_case f1 ... fn x) =
  2141      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2142         ...
  2143        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2144      )
  2145 
  2146   and a theorem `split_t_case_asm' of the form
  2147 
  2148   P(t_case f1 ... fn x) =
  2149     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2150         ...
  2151        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2152      )
  2153   which can be added to a simpset via `addsplits'. The existing theorems
  2154   expand_list_case and expand_option_case have been renamed to
  2155   split_list_case and split_option_case.
  2156 
  2157 * HOL/Arithmetic:
  2158   - `pred n' is automatically converted to `n-1'.
  2159     Users are strongly encouraged not to use `pred' any longer,
  2160     because it will disappear altogether at some point.
  2161   - Users are strongly encouraged to write "0 < n" rather than
  2162     "n ~= 0". Theorems and proof tools have been modified towards this
  2163     `standard'.
  2164 
  2165 * HOL/Lists:
  2166   the function "set_of_list" has been renamed "set" (and its theorems too);
  2167   the function "nth" now takes its arguments in the reverse order and
  2168   has acquired the infix notation "!" as in "xs!n".
  2169 
  2170 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2171 
  2172 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2173   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2174 
  2175 * HOL/record: extensible records with schematic structural subtyping
  2176 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2177 still lacks various theorems and concrete record syntax;
  2178 
  2179 
  2180 *** HOLCF ***
  2181 
  2182 * removed "axioms" and "generated by" sections;
  2183 
  2184 * replaced "ops" section by extended "consts" section, which is capable of
  2185   handling the continuous function space "->" directly;
  2186 
  2187 * domain package:
  2188   . proves theorems immediately and stores them in the theory,
  2189   . creates hierachical name space,
  2190   . now uses normal mixfix annotations (instead of cinfix...),
  2191   . minor changes to some names and values (for consistency),
  2192   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2193   . separator between mutual domain defs: changed "," to "and",
  2194   . improved handling of sort constraints;  now they have to
  2195     appear on the left-hand side of the equations only;
  2196 
  2197 * fixed LAM <x,y,zs>.b syntax;
  2198 
  2199 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2200 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2201 
  2202 
  2203 *** FOL and ZF ***
  2204 
  2205 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2206   with `addloop' of the simplifier to faciliate case splitting in premises.
  2207 
  2208 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2209 in HOL, they strip ALL and --> from proved theorems;
  2210 
  2211 
  2212 
  2213 New in Isabelle94-8 (May 1997)
  2214 ------------------------------
  2215 
  2216 *** General Changes ***
  2217 
  2218 * new utilities to build / run / maintain Isabelle etc. (in parts
  2219 still somewhat experimental); old Makefiles etc. still functional;
  2220 
  2221 * new 'Isabelle System Manual';
  2222 
  2223 * INSTALL text, together with ./configure and ./build scripts;
  2224 
  2225 * reimplemented type inference for greater efficiency, better error
  2226 messages and clean internal interface;
  2227 
  2228 * prlim command for dealing with lots of subgoals (an easier way of
  2229 setting goals_limit);
  2230 
  2231 
  2232 *** Syntax ***
  2233 
  2234 * supports alternative (named) syntax tables (parser and pretty
  2235 printer); internal interface is provided by add_modesyntax(_i);
  2236 
  2237 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2238 be used in conjunction with the Isabelle symbol font; uses the
  2239 "symbols" syntax table;
  2240 
  2241 * added token_translation interface (may translate name tokens in
  2242 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2243 the current print_mode); IMPORTANT: user print translation functions
  2244 are responsible for marking newly introduced bounds
  2245 (Syntax.mark_boundT);
  2246 
  2247 * token translations for modes "xterm" and "xterm_color" that display
  2248 names in bold, underline etc. or colors (which requires a color
  2249 version of xterm);
  2250 
  2251 * infixes may now be declared with names independent of their syntax;
  2252 
  2253 * added typed_print_translation (like print_translation, but may
  2254 access type of constant);
  2255 
  2256 
  2257 *** Classical Reasoner ***
  2258 
  2259 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2260 some limitations.  Blast_tac...
  2261   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2262   + ignores elimination rules that don't have the correct format
  2263         (the conclusion MUST be a formula variable)
  2264   + ignores types, which can make HOL proofs fail
  2265   + rules must not require higher-order unification, e.g. apply_type in ZF
  2266     [message "Function Var's argument not a bound variable" relates to this]
  2267   + its proof strategy is more general but can actually be slower
  2268 
  2269 * substitution with equality assumptions no longer permutes other
  2270 assumptions;
  2271 
  2272 * minor changes in semantics of addafter (now called addaltern); renamed
  2273 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2274 (and access functions for it);
  2275 
  2276 * improved combination of classical reasoner and simplifier:
  2277   + functions for handling clasimpsets
  2278   + improvement of addss: now the simplifier is called _after_ the
  2279     safe steps.
  2280   + safe variant of addss called addSss: uses safe simplifications
  2281     _during_ the safe steps. It is more complete as it allows multiple
  2282     instantiations of unknowns (e.g. with slow_tac).
  2283 
  2284 *** Simplifier ***
  2285 
  2286 * added interface for simplification procedures (functions that
  2287 produce *proven* rewrite rules on the fly, depending on current
  2288 redex);
  2289 
  2290 * ordering on terms as parameter (used for ordered rewriting);
  2291 
  2292 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2293 
  2294 * the solver is now split into a safe and an unsafe part.
  2295 This should be invisible for the normal user, except that the
  2296 functions setsolver and addsolver have been renamed to setSolver and
  2297 addSolver; added safe_asm_full_simp_tac;
  2298 
  2299 
  2300 *** HOL ***
  2301 
  2302 * a generic induction tactic `induct_tac' which works for all datatypes and
  2303 also for type `nat';
  2304 
  2305 * a generic case distinction tactic `exhaust_tac' which works for all
  2306 datatypes and also for type `nat';
  2307 
  2308 * each datatype comes with a function `size';
  2309 
  2310 * patterns in case expressions allow tuple patterns as arguments to
  2311 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2312 
  2313 * primrec now also works with type nat;
  2314 
  2315 * recdef: a new declaration form, allows general recursive functions to be
  2316 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2317 
  2318 * the constant for negation has been renamed from "not" to "Not" to
  2319 harmonize with FOL, ZF, LK, etc.;
  2320 
  2321 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2322 infinite lists;
  2323 
  2324 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2325 
  2326 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2327 problems in commutative rings, using axiomatic type classes for + and *;
  2328 
  2329 * more examples in HOL/MiniML and HOL/Auth;
  2330 
  2331 * more default rewrite rules for quantifiers, union/intersection;
  2332 
  2333 * a new constant `arbitrary == @x.False';
  2334 
  2335 * HOLCF/IOA replaces old HOL/IOA;
  2336 
  2337 * HOLCF changes: derived all rules and arities
  2338   + axiomatic type classes instead of classes
  2339   + typedef instead of faking type definitions
  2340   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2341   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2342   + eliminated the types void, one, tr
  2343   + use unit lift and bool lift (with translations) instead of one and tr
  2344   + eliminated blift from Lift3.thy (use Def instead of blift)
  2345   all eliminated rules are derived as theorems --> no visible changes ;
  2346 
  2347 
  2348 *** ZF ***
  2349 
  2350 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2351 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2352 as ZF_cs addSIs [equalityI];
  2353 
  2354 
  2355 
  2356 New in Isabelle94-7 (November 96)
  2357 ---------------------------------
  2358 
  2359 * allowing negative levels (as offsets) in prlev and choplev;
  2360 
  2361 * super-linear speedup for large simplifications;
  2362 
  2363 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2364 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2365 FAIL); can suppress it using the command Delsimps (ex_simps @
  2366 all_simps); De Morgan laws are also now included, by default;
  2367 
  2368 * improved printing of ==>  :  ~:
  2369 
  2370 * new object-logic "Sequents" adds linear logic, while replacing LK
  2371 and Modal (thanks to Sara Kalvala);
  2372 
  2373 * HOL/Auth: correctness proofs for authentication protocols;
  2374 
  2375 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2376 examples on HOL/Auth);
  2377 
  2378 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2379 the rewriter and classical reasoner simultaneously;
  2380 
  2381 * function uresult no longer returns theorems in "standard" format;
  2382 regain previous version by: val uresult = standard o uresult;
  2383 
  2384 
  2385 
  2386 New in Isabelle94-6
  2387 -------------------
  2388 
  2389 * oracles -- these establish an interface between Isabelle and trusted
  2390 external reasoners, which may deliver results as theorems;
  2391 
  2392 * proof objects (in particular record all uses of oracles);
  2393 
  2394 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2395 
  2396 * "constdefs" section in theory files;
  2397 
  2398 * "primrec" section (HOL) no longer requires names;
  2399 
  2400 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2401 
  2402 
  2403 
  2404 New in Isabelle94-5
  2405 -------------------
  2406 
  2407 * reduced space requirements;
  2408 
  2409 * automatic HTML generation from theories;
  2410 
  2411 * theory files no longer require "..." (quotes) around most types;
  2412 
  2413 * new examples, including two proofs of the Church-Rosser theorem;
  2414 
  2415 * non-curried (1994) version of HOL is no longer distributed;
  2416 
  2417 
  2418 
  2419 New in Isabelle94-4
  2420 -------------------
  2421 
  2422 * greatly reduced space requirements;
  2423 
  2424 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2425 
  2426 * searchable theorem database (see the section "Retrieving theorems" on
  2427 page 8 of the Reference Manual);
  2428 
  2429 * new examples, including Grabczewski's monumental case study of the
  2430 Axiom of Choice;
  2431 
  2432 * The previous version of HOL renamed to Old_HOL;
  2433 
  2434 * The new version of HOL (previously called CHOL) uses a curried syntax
  2435 for functions.  Application looks like f a b instead of f(a,b);
  2436 
  2437 * Mutually recursive inductive definitions finally work in HOL;
  2438 
  2439 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2440 translates to the operator "split";
  2441 
  2442 
  2443 
  2444 New in Isabelle94-3
  2445 -------------------
  2446 
  2447 * new infix operator, addss, allowing the classical reasoner to
  2448 perform simplification at each step of its search.  Example:
  2449         fast_tac (cs addss ss)
  2450 
  2451 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2452 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2453 look like (a,b) instead of <a,b>;
  2454 
  2455 * PLEASE NOTE: CHOL will eventually replace HOL!
  2456 
  2457 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2458 It translates to the operator "split".  A new theory of integers is available;
  2459 
  2460 * In ZF, integer numerals now denote two's-complement binary integers.
  2461 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2462 
  2463 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2464 of the Axiom of Choice;
  2465 
  2466 
  2467 
  2468 New in Isabelle94-2
  2469 -------------------
  2470 
  2471 * Significantly faster resolution;
  2472 
  2473 * the different sections in a .thy file can now be mixed and repeated
  2474 freely;
  2475 
  2476 * Database of theorems for FOL, HOL and ZF.  New
  2477 commands including qed, qed_goal and bind_thm store theorems in the database.
  2478 
  2479 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2480 a given theory (thms_of), or find out what theory a theorem was proved in
  2481 (theory_of_thm);
  2482 
  2483 * Bugs fixed in the inductive definition and datatype packages;
  2484 
  2485 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2486 and HOL_dup_cs obsolete;
  2487 
  2488 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2489 have been removed;
  2490 
  2491 * Simpler definition of function space in ZF;
  2492 
  2493 * new results about cardinal and ordinal arithmetic in ZF;
  2494 
  2495 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2496 types;
  2497 
  2498 
  2499 $Id$