NEWS
author kleing
Tue Apr 13 07:25:46 2004 +0200 (2004-04-13)
changeset 14547 e0c0179100c9
parent 14536 43e436a4f293
child 14551 2cb6ff394bfb
permissions -rw-r--r--
isabelle.css
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
    10   Replaces linorder.ML.
    11 
    12 * Pure: Greek letters (except small lambda, \<lambda>), as well as gothic
    13   (\<aa>...\<zz>\<AA>...\<ZZ>), caligraphic (\<A>...\<Z>), and euler
    14   (\<a>...\<z>), are now considered normal letters, and can therefore
    15   be used anywhere where an ASCII letter (a...zA...Z) has until
    16   now. COMPATIBILITY: This obviously changes the parsing of some
    17   terms, especially where a symbol has been used as a binder, say
    18   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
    19   as an identifier.  Fix it by inserting a space around former
    20   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
    21   existing theory and ML files.
    22 
    23 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
    24 
    25 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now 
    26   allowed in identifiers. Similar to greek letters \<^isub> is now considered 
    27   a normal (but invisible) letter. For multiple letter subscripts repeat 
    28   \<^isub> like this: x\<^isub>1\<^isub>2. 
    29 
    30 * Pure: There are now sub-/superscripts that can span more than one
    31   character. Text between \<^bsub> and \<^esub> is set in subscript in
    32   PG and LaTeX, text between \<^bsup> and \<^esup> in superscript. The
    33   new control characters are not identifier parts.
    34 
    35 * Pure: Control-symbols of the form \<^raw...> will literally print the
    36   content of ... to the latex file instead of \isacntrl... . The ... 
    37   accepts all printable characters excluding the end bracket >.
    38 
    39 * Pure: Symbols may only start with one backslash: \<...>. \\<...> is no 
    40   longer accepted by the scanner.
    41 
    42 * Pure: Using new Isar command "finalconsts" (or the ML functions
    43   Theory.add_finals or Theory.add_finals_i) it is now possible to
    44   declare constants "final", which prevents their being given a definition
    45   later.  It is useful for constants whose behaviour is fixed axiomatically
    46   rather than definitionally, such as the meta-logic connectives.
    47 
    48 * Pure: It is now illegal to specify Theory.ML explicitly as a dependency
    49   in the files section of the theory Theory. (This is more of a diagnostic
    50   than a restriction, as the theory loader screws up if Theory.ML is manually
    51   loaded.)
    52 
    53 * Presentation: generated HTML now uses a CSS style sheet to make layout
    54   (somewhat) independet of content. It is copied from lib/html/isabelle.css. 
    55   It can be changed to alter the colors/layout of generated pages.
    56 
    57 *** Isar ***
    58 
    59 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
    60   cut_tac, subgoal_tac and thin_tac:
    61   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    62     locales are no longer forced to write Isar proof scripts.
    63     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    64     emulations.
    65   - INCOMPATIBILITY: names of variables to be instantiated may no
    66     longer be enclosed in quotes.  Instead, precede variable name with `?'.
    67     This is consistent with the instantiation attribute "where".
    68 
    69 * Attributes "where" and "of":
    70   - Now take type variables of instantiated theorem into account when reading
    71     the instantiation string.  This fixes a bug that caused instantiated
    72     theorems to have too special types in some circumstances.
    73   - "where" permits explicit instantiations of type variables.
    74 
    75 * Calculation commands "moreover" and "also":
    76   Do not reset facts ("this") any more.
    77 
    78 * Locales:
    79   - Goal statements involving the context element "includes" no longer
    80     generate theorems with internal delta predicates (those ending on
    81     "_axioms") in the premise.
    82     Resolve particular premise with <locale>.intro to obtain old form.
    83   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
    84     specification and "includes" elements in goal statement.
    85   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
    86     [intro?] and [elim?] (respectively) by default.
    87   - Experimental command for instantiation of locales in proof contexts:
    88         instantiate <label>: <loc>
    89     Instantiates locale <loc> and adds all its theorems to the current context
    90     taking into account their attributes, and qualifying their names with
    91     <label>.  If the locale has assumptions, a chained fact of the form
    92     "<loc> t1 ... tn" is expected from which instantiations of the parameters
    93     are derived.
    94     A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
    95 
    96 * HOL: Tactic emulation methods induct_tac and case_tac understand static
    97   (Isar) contexts.
    98 
    99 *** HOL ***
   100 
   101 * Simplifier:
   102   - Much improved handling of linear and partial orders.
   103     Reasoners for linear and partial orders are set up for type classes
   104     "linorder" and "order" respectively, and are added to the default simpset
   105     as solvers.  This means that the simplifier can build transitivity chains
   106     to solve goals from the assumptions.
   107   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   108     of blast or auto after simplification become unnecessary because the goal
   109     is solved by simplification already.
   110 
   111 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws, 
   112     all proved in axiomatic type classes for semirings, rings and fields.
   113 
   114 * Numerics:
   115   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   116     now formalized using the Ring_and_Field theory mentioned above. 
   117   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   118     than before, because now they are set up once in a generic manner.
   119   - INCOMPATIBILITY: many type-specific arithmetic laws have gone. 
   120     Look for the general versions in Ring_and_Field (and Power if they concern
   121     exponentiation).
   122 
   123 * Type "rat" of the rational numbers is now available in HOL-Complex.
   124 
   125 * Records:
   126   - Record types are now by default printed with their type abbreviation
   127     instead of the list of all field types. This can be configured via
   128     the reference "print_record_type_abbr".
   129   - Simproc "record_upd_simproc" for simplification of multiple updates added 
   130     (not enabled by default).
   131   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   132     EX x. x = sel r to True (not enabled by default).
   133   - Tactic "record_split_simp_tac" to split and simplify records added.
   134  
   135 * 'specification' command added, allowing for definition by
   136   specification.  There is also an 'ax_specification' command that
   137   introduces the new constants axiomatically.
   138 
   139 * arith(_tac) is now able to generate counterexamples for reals as well.
   140 
   141 * HOL-Algebra: new locale "ring" for non-commutative rings.
   142 
   143 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   144  defintions, thanks to Sava Krsti\'{c} and John Matthews.
   145 
   146 * Unions and Intersections:
   147   The x-symbol output syntax of UN and INT has been changed
   148   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   149   i.e. the index formulae has become a subscript, like in normal math.
   150   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   151   The subscript version is also accepted as input syntax.
   152 
   153 * Unions and Intersections over Intervals:
   154   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is 
   155   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A" 
   156   like in normal math, and corresponding versions for < and for intersection.
   157 
   158 * ML: the legacy theory structures Int and List have been removed. They had
   159   conflicted with ML Basis Library structures having the same names.
   160 
   161 * 'refute' command added to search for (finite) countermodels.  Only works
   162   for a fragment of HOL.  The installation of an external SAT solver is
   163   highly recommended.  See "HOL/Refute.thy" for details.
   164 
   165 
   166 *** HOLCF ***
   167 
   168 * Streams now come with concatenation and are part of the HOLCF image
   169 
   170 New in Isabelle2003 (May 2003)
   171 --------------------------------
   172 
   173 *** General ***
   174 
   175 * Provers/simplifier:
   176 
   177   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   178     Assumptions are now subject to complete mutual simplification,
   179     not just from left to right. The simplifier now preserves
   180     the order of assumptions.
   181 
   182     Potential INCOMPATIBILITY:
   183 
   184     -- simp sometimes diverges where the old version did
   185        not, e.g. invoking simp on the goal
   186 
   187         [| P (f x); y = x; f x = f y |] ==> Q
   188 
   189        now gives rise to the infinite reduction sequence
   190 
   191         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   192 
   193        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   194        kind of problem.
   195 
   196     -- Tactics combining classical reasoner and simplification (such as auto)
   197        are also affected by this change, because many of them rely on
   198        simp. They may sometimes diverge as well or yield a different numbers
   199        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   200        in case of problems. Sometimes subsequent calls to the classical
   201        reasoner will fail because a preceeding call to the simplifier too
   202        eagerly simplified the goal, e.g. deleted redundant premises.
   203 
   204   - The simplifier trace now shows the names of the applied rewrite rules
   205 
   206   - You can limit the number of recursive invocations of the simplifier
   207     during conditional rewriting (where the simplifie tries to solve the
   208     conditions before applying the rewrite rule):
   209     ML "simp_depth_limit := n"
   210     where n is an integer. Thus you can force termination where previously
   211     the simplifier would diverge.
   212 
   213   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   214 
   215   - No longer aborts on failed congruence proof.  Instead, the
   216     congruence is ignored.
   217 
   218 * Pure: New generic framework for extracting programs from constructive
   219   proofs. See HOL/Extraction.thy for an example instantiation, as well
   220   as HOL/Extraction for some case studies.
   221 
   222 * Pure: The main goal of the proof state is no longer shown by default, only
   223 the subgoals. This behaviour is controlled by a new flag.
   224    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   225 (ML: Proof.show_main_goal).
   226 
   227 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   228 rules whose conclusion matches subgoal 1:
   229       PG menu: Isabelle/Isar -> Show me -> matching rules
   230 The rules are ordered by how closely they match the subgoal.
   231 In particular, rules that solve a subgoal outright are displayed first
   232 (or rather last, the way they are printed).
   233 (ML: ProofGeneral.print_intros())
   234 
   235 * Pure: New flag trace_unify_fail causes unification to print
   236 diagnostic information (PG: in trace buffer) when it fails. This is
   237 useful for figuring out why single step proofs like rule, erule or
   238 assumption failed.
   239 
   240 * Pure: Locale specifications now produce predicate definitions
   241 according to the body of text (covering assumptions modulo local
   242 definitions); predicate "loc_axioms" covers newly introduced text,
   243 while "loc" is cumulative wrt. all included locale expressions; the
   244 latter view is presented only on export into the global theory
   245 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   246 on the old view without predicates;
   247 
   248 * Pure: predefined locales "var" and "struct" are useful for sharing
   249 parameters (as in CASL, for example); just specify something like
   250 ``var x + var y + struct M'' as import;
   251 
   252 * Pure: improved thms_containing: proper indexing of facts instead of
   253 raw theorems; check validity of results wrt. current name space;
   254 include local facts of proof configuration (also covers active
   255 locales), cover fixed variables in index; may use "_" in term
   256 specification; an optional limit for the number of printed facts may
   257 be given (the default is 40);
   258 
   259 * Pure: disallow duplicate fact bindings within new-style theory files
   260 (batch-mode only);
   261 
   262 * Provers: improved induct method: assumptions introduced by case
   263 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   264 the goal statement); "foo" still refers to all facts collectively;
   265 
   266 * Provers: the function blast.overloaded has been removed: all constants
   267 are regarded as potentially overloaded, which improves robustness in exchange
   268 for slight decrease in efficiency;
   269 
   270 * Provers/linorder: New generic prover for transitivity reasoning over
   271 linear orders.  Note: this prover is not efficient!
   272 
   273 * Isar: preview of problems to finish 'show' now produce an error
   274 rather than just a warning (in interactive mode);
   275 
   276 
   277 *** HOL ***
   278 
   279 * arith(_tac)
   280 
   281  - Produces a counter example if it cannot prove a goal.
   282    Note that the counter example may be spurious if the goal is not a formula
   283    of quantifier-free linear arithmetic.
   284    In ProofGeneral the counter example appears in the trace buffer.
   285 
   286  - Knows about div k and mod k where k is a numeral of type nat or int.
   287 
   288  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   289    linear arithmetic fails. This takes account of quantifiers and divisibility.
   290    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   291 
   292 * simp's arithmetic capabilities have been enhanced a bit: it now
   293 takes ~= in premises into account (by performing a case split);
   294 
   295 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   296 are distributed over a sum of terms;
   297 
   298 * New tactic "trans_tac" and method "trans" instantiate
   299 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   300 "<=", "<" and "="). 
   301 
   302 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   303 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   304 
   305 * 'typedef' command has new option "open" to suppress the set
   306 definition;
   307 
   308 * functions Min and Max on finite sets have been introduced (theory
   309 Finite_Set);
   310 
   311 * attribute [symmetric] now works for relations as well; it turns
   312 (x,y) : R^-1 into (y,x) : R, and vice versa;
   313 
   314 * induct over a !!-quantified statement (say !!x1..xn):
   315   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   316 
   317 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   318 %x. None. Warning: empty_def now refers to the previously hidden definition
   319 of the empty set.
   320 
   321 * Algebra: formalization of classical algebra.  Intended as base for
   322 any algebraic development in Isabelle.  Currently covers group theory
   323 (up to Sylow's theorem) and ring theory (Universal Property of
   324 Univariate Polynomials).  Contributions welcome;
   325 
   326 * GroupTheory: deleted, since its material has been moved to Algebra;
   327 
   328 * Complex: new directory of the complex numbers with numeric constants, 
   329 nonstandard complex numbers, and some complex analysis, standard and 
   330 nonstandard (Jacques Fleuriot);
   331 
   332 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   333 
   334 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   335 Fleuriot);
   336 
   337 * Real/HahnBanach: updated and adapted to locales;
   338 
   339 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   340 Gray and Kramer);
   341 
   342 * UNITY: added the Meier-Sanders theory of progress sets;
   343 
   344 * MicroJava: bytecode verifier and lightweight bytecode verifier
   345 as abstract algorithms, instantiated to the JVM;
   346 
   347 * Bali: Java source language formalization. Type system, operational
   348 semantics, axiomatic semantics. Supported language features:
   349 classes, interfaces, objects,virtual methods, static methods,
   350 static/instance fields, arrays, access modifiers, definite
   351 assignment, exceptions.
   352 
   353 
   354 *** ZF ***
   355 
   356 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   357 universe, etc.);
   358 
   359 * Main ZF: virtually all theories converted to new-style format;
   360 
   361 
   362 *** ML ***
   363 
   364 * Pure: Tactic.prove provides sane interface for internal proofs;
   365 omits the infamous "standard" operation, so this is more appropriate
   366 than prove_goalw_cterm in many situations (e.g. in simprocs);
   367 
   368 * Pure: improved error reporting of simprocs;
   369 
   370 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   371 up simprocs;
   372 
   373 
   374 *** Document preparation ***
   375 
   376 * uses \par instead of \\ for line breaks in theory text. This may
   377 shift some page breaks in large documents. To get the old behaviour
   378 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   379 
   380 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   381 other packages
   382 
   383 * \<euro> now needs package babel/greek instead of marvosym (which
   384 broke \Rightarrow)
   385 
   386 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   387 textcomp package)
   388 
   389 
   390 New in Isabelle2002 (March 2002)
   391 --------------------------------
   392 
   393 *** Document preparation ***
   394 
   395 * greatly simplified document preparation setup, including more
   396 graceful interpretation of isatool usedir -i/-d/-D options, and more
   397 instructive isatool mkdir; users should basically be able to get
   398 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   399 users may run a separate document processing stage manually like this:
   400 "isatool usedir -D output HOL Test && isatool document Test/output";
   401 
   402 * theory dependency graph may now be incorporated into documents;
   403 isatool usedir -g true will produce session_graph.eps/.pdf for use
   404 with \includegraphics of LaTeX;
   405 
   406 * proper spacing of consecutive markup elements, especially text
   407 blocks after section headings;
   408 
   409 * support bold style (for single symbols only), input syntax is like
   410 this: "\<^bold>\<alpha>" or "\<^bold>A";
   411 
   412 * \<bullet> is now output as bold \cdot by default, which looks much
   413 better in printed text;
   414 
   415 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   416 note that these symbols are currently unavailable in Proof General /
   417 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   418 
   419 * isatool latex no longer depends on changed TEXINPUTS, instead
   420 isatool document copies the Isabelle style files to the target
   421 location;
   422 
   423 
   424 *** Isar ***
   425 
   426 * Pure/Provers: improved proof by cases and induction;
   427   - 'case' command admits impromptu naming of parameters (such as
   428     "case (Suc n)");
   429   - 'induct' method divinates rule instantiation from the inductive
   430     claim; no longer requires excessive ?P bindings for proper
   431     instantiation of cases;
   432   - 'induct' method properly enumerates all possibilities of set/type
   433     rules; as a consequence facts may be also passed through *type*
   434     rules without further ado;
   435   - 'induct' method now derives symbolic cases from the *rulified*
   436     rule (before it used to rulify cases stemming from the internal
   437     atomized version); this means that the context of a non-atomic
   438     statement becomes is included in the hypothesis, avoiding the
   439     slightly cumbersome show "PROP ?case" form;
   440   - 'induct' may now use elim-style induction rules without chaining
   441     facts, using ``missing'' premises from the goal state; this allows
   442     rules stemming from inductive sets to be applied in unstructured
   443     scripts, while still benefitting from proper handling of non-atomic
   444     statements; NB: major inductive premises need to be put first, all
   445     the rest of the goal is passed through the induction;
   446   - 'induct' proper support for mutual induction involving non-atomic
   447     rule statements (uses the new concept of simultaneous goals, see
   448     below);
   449   - append all possible rule selections, but only use the first
   450     success (no backtracking);
   451   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   452   - undeclared rule case names default to numbers 1, 2, 3, ...;
   453   - added 'print_induct_rules' (covered by help item in recent Proof
   454     General versions);
   455   - moved induct/cases attributes to Pure, methods to Provers;
   456   - generic method setup instantiated for FOL and HOL;
   457 
   458 * Pure: support multiple simultaneous goal statements, for example
   459 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   460 meta-level mechanism, this acts as if several individual goals had
   461 been stated separately; in particular common proof methods need to be
   462 repeated in order to cover all claims; note that a single elimination
   463 step is *not* sufficient to establish the two conjunctions, so this
   464 fails:
   465 
   466   assume "A & B" then have A and B ..   (*".." fails*)
   467 
   468 better use "obtain" in situations as above; alternative refer to
   469 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   470 
   471 * Pure: proper integration with ``locales''; unlike the original
   472 version by Florian Kammüller, Isar locales package high-level proof
   473 contexts rather than raw logical ones (e.g. we admit to include
   474 attributes everywhere); operations on locales include merge and
   475 rename; support for implicit arguments (``structures''); simultaneous
   476 type-inference over imports and text; see also HOL/ex/Locales.thy for
   477 some examples;
   478 
   479 * Pure: the following commands have been ``localized'', supporting a
   480 target locale specification "(in name)": 'lemma', 'theorem',
   481 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   482 stored both within the locale and at the theory level (exported and
   483 qualified by the locale name);
   484 
   485 * Pure: theory goals may now be specified in ``long'' form, with
   486 ad-hoc contexts consisting of arbitrary locale elements. for example
   487 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   488 definitions may be given, too); the result is a meta-level rule with
   489 the context elements being discharged in the obvious way;
   490 
   491 * Pure: new proof command 'using' allows to augment currently used
   492 facts after a goal statement ('using' is syntactically analogous to
   493 'apply', but acts on the goal's facts only); this allows chained facts
   494 to be separated into parts given before and after a claim, as in
   495 ``from a and b have C using d and e <proof>'';
   496 
   497 * Pure: renamed "antecedent" case to "rule_context";
   498 
   499 * Pure: new 'judgment' command records explicit information about the
   500 object-logic embedding (used by several tools internally); no longer
   501 use hard-wired "Trueprop";
   502 
   503 * Pure: added 'corollary' command;
   504 
   505 * Pure: fixed 'token_translation' command;
   506 
   507 * Pure: removed obsolete 'exported' attribute;
   508 
   509 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   510 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   511 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   512 
   513 * Pure: method 'atomize' presents local goal premises as object-level
   514 statements (atomic meta-level propositions); setup controlled via
   515 rewrite rules declarations of 'atomize' attribute; example
   516 application: 'induct' method with proper rule statements in improper
   517 proof *scripts*;
   518 
   519 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   520 now consider the syntactic context of assumptions, giving a better
   521 chance to get type-inference of the arguments right (this is
   522 especially important for locales);
   523 
   524 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   525 mode;
   526 
   527 * Pure/obtain: the formal conclusion "thesis", being marked as
   528 ``internal'', may no longer be reference directly in the text;
   529 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   530 situations;
   531 
   532 * Pure: generic 'sym' attribute which declares a rule both as pure
   533 'elim?' and for the 'symmetric' operation;
   534 
   535 * Pure: marginal comments ``--'' may now occur just anywhere in the
   536 text; the fixed correlation with particular command syntax has been
   537 discontinued;
   538 
   539 * Pure: new method 'rules' is particularly well-suited for proof
   540 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   541 but often produces more compact proof terms with less detours;
   542 
   543 * Pure/Provers/classical: simplified integration with pure rule
   544 attributes and methods; the classical "intro?/elim?/dest?"
   545 declarations coincide with the pure ones; the "rule" method no longer
   546 includes classically swapped intros; "intro" and "elim" methods no
   547 longer pick rules from the context; also got rid of ML declarations
   548 AddXIs/AddXEs/AddXDs; all of this has some potential for
   549 INCOMPATIBILITY;
   550 
   551 * Provers/classical: attribute 'swapped' produces classical inversions
   552 of introduction rules;
   553 
   554 * Provers/simplifier: 'simplified' attribute may refer to explicit
   555 rules instead of full simplifier context; 'iff' attribute handles
   556 conditional rules;
   557 
   558 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   559 
   560 * HOL: 'recdef' now fails on unfinished automated proofs, use
   561 "(permissive)" option to recover old behavior;
   562 
   563 * HOL: 'inductive' no longer features separate (collective) attributes
   564 for 'intros' (was found too confusing);
   565 
   566 * HOL: properly declared induction rules less_induct and
   567 wf_induct_rule;
   568 
   569 
   570 *** HOL ***
   571 
   572 * HOL: moved over to sane numeral syntax; the new policy is as
   573 follows:
   574 
   575   - 0 and 1 are polymorphic constants, which are defined on any
   576   numeric type (nat, int, real etc.);
   577 
   578   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   579   binary representation internally;
   580 
   581   - type nat has special constructor Suc, and generally prefers Suc 0
   582   over 1::nat and Suc (Suc 0) over 2::nat;
   583 
   584 This change may cause significant problems of INCOMPATIBILITY; here
   585 are some hints on converting existing sources:
   586 
   587   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   588   entities, so expressions involving "-" (unary or binary minus) need
   589   to be spaced properly;
   590 
   591   - existing occurrences of "1" may need to be constraint "1::nat" or
   592   even replaced by Suc 0; similar for old "2";
   593 
   594   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   595 
   596   - remove all special provisions on numerals in proofs;
   597 
   598 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   599 representation (depends on bin_arith_simps in the default context);
   600 
   601 * HOL: symbolic syntax for x^2 (numeral 2);
   602 
   603 * HOL: the class of all HOL types is now called "type" rather than
   604 "term"; INCOMPATIBILITY, need to adapt references to this type class
   605 in axclass/classes, instance/arities, and (usually rare) occurrences
   606 in typings (of consts etc.); internally the class is called
   607 "HOL.type", ML programs should refer to HOLogic.typeS;
   608 
   609 * HOL/record package improvements:
   610   - new derived operations "fields" to build a partial record section,
   611     "extend" to promote a fixed record to a record scheme, and
   612     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   613     declared as simp by default;
   614   - shared operations ("more", "fields", etc.) now need to be always
   615     qualified) --- potential INCOMPATIBILITY;
   616   - removed "make_scheme" operations (use "make" with "extend") --
   617     INCOMPATIBILITY;
   618   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   619   - provides cases/induct rules for use with corresponding Isar
   620     methods (for concrete records, record schemes, concrete more
   621     parts, and schematic more parts -- in that order);
   622   - internal definitions directly based on a light-weight abstract
   623     theory of product types over typedef rather than datatype;
   624 
   625 * HOL: generic code generator for generating executable ML code from
   626 specifications; specific support for HOL constructs such as inductive
   627 datatypes and sets, as well as recursive functions; can be invoked
   628 via 'generate_code' theory section;
   629 
   630 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   631 
   632 * HOL: consolidated and renamed several theories.  In particular:
   633 	Ord.thy has been absorbed into HOL.thy
   634 	String.thy has been absorbed into List.thy
   635  
   636 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   637 (beware of argument permutation!);
   638 
   639 * HOL: linorder_less_split superseded by linorder_cases;
   640 
   641 * HOL/List: "nodups" renamed to "distinct";
   642 
   643 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   644 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   645   - Ex_def has changed, now need to use some_eq_ex
   646 
   647 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   648 in this (rare) case use:
   649 
   650   delSWrapper "split_all_tac"
   651   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   652 
   653 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   654 MAY FAIL;
   655 
   656 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   657 Isabelle's type classes, ^ on functions and relations has too general
   658 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   659 necessary to attach explicit type constraints;
   660 
   661 * HOL/Relation: the prefix name of the infix "O" has been changed from
   662 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   663 renamed accordingly (eg "compI" -> "rel_compI").
   664 
   665 * HOL: syntax translations now work properly with numerals and records
   666 expressions;
   667 
   668 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   669 of "lam" -- INCOMPATIBILITY;
   670 
   671 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   672 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   673 renamed "Product_Type.unit";
   674 
   675 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   676 
   677 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   678 the "cases" method);
   679 
   680 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   681 Florian Kammüller);
   682 
   683 * HOL/IMP: updated and converted to new-style theory format; several
   684 parts turned into readable document, with proper Isar proof texts and
   685 some explanations (by Gerwin Klein);
   686 
   687 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   688 
   689 * HOL-Hyperreal is now a logic image;
   690 
   691 
   692 *** HOLCF ***
   693 
   694 * Isar: consts/constdefs supports mixfix syntax for continuous
   695 operations;
   696 
   697 * Isar: domain package adapted to new-style theory format, e.g. see
   698 HOLCF/ex/Dnat.thy;
   699 
   700 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   701 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   702 lift.induct_tac, always use UU instead of Undef;
   703 
   704 * HOLCF/IMP: updated and converted to new-style theory;
   705 
   706 
   707 *** ZF ***
   708 
   709 * Isar: proper integration of logic-specific tools and packages,
   710 including theory commands '(co)inductive', '(co)datatype',
   711 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   712 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   713 
   714 * theory Main no longer includes AC; for the Axiom of Choice, base
   715 your theory on Main_ZFC;
   716 
   717 * the integer library now covers quotients and remainders, with many
   718 laws relating division to addition, multiplication, etc.;
   719 
   720 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   721 typeless version of the formalism;
   722 
   723 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   724 format;
   725 
   726 * ZF/Induct: new directory for examples of inductive definitions,
   727 including theory Multiset for multiset orderings; converted to
   728 new-style theory format;
   729 
   730 * ZF: many new theorems about lists, ordinals, etc.;
   731 
   732 
   733 *** General ***
   734 
   735 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   736 variable proof controls level of detail: 0 = no proofs (only oracle
   737 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   738 also ref manual for further ML interfaces;
   739 
   740 * Pure/axclass: removed obsolete ML interface
   741 goal_subclass/goal_arity;
   742 
   743 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   744 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   745 separate tokens, so expressions involving minus need to be spaced
   746 properly;
   747 
   748 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   749 rather than "infixl" or "infixr";
   750 
   751 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   752 sort constraint specifications in type inference; e.g. "x::_::foo"
   753 ensures that the type of "x" is of sort "foo" (but not necessarily a
   754 type variable);
   755 
   756 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   757 control output of nested => (types); the default behavior is
   758 "type_brackets";
   759 
   760 * Pure/syntax: builtin parse translation for "_constify" turns valued
   761 tokens into AST constants;
   762 
   763 * Pure/syntax: prefer later declarations of translations and print
   764 translation functions; potential INCOMPATIBILITY: need to reverse
   765 multiple declarations for same syntax element constant;
   766 
   767 * Pure/show_hyps reset by default (in accordance to existing Isar
   768 practice);
   769 
   770 * Provers/classical: renamed addaltern to addafter, addSaltern to
   771 addSafter;
   772 
   773 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   774 as well;
   775 
   776 * system: tested support for MacOS X; should be able to get Isabelle +
   777 Proof General to work in a plain Terminal after installing Poly/ML
   778 (e.g. from the Isabelle distribution area) and GNU bash alone
   779 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   780 support requires further installations, e.g. from
   781 http://fink.sourceforge.net/);
   782 
   783 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   784 
   785 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   786 of 40 MB), cf. ML_OPTIONS;
   787 
   788 * system: Proof General keywords specification is now part of the
   789 Isabelle distribution (see etc/isar-keywords.el);
   790 
   791 * system: support for persistent Proof General sessions (refrain from
   792 outdating all loaded theories on startup); user may create writable
   793 logic images like this: ``isabelle -q HOL Test'';
   794 
   795 * system: smart selection of Isabelle process versus Isabelle
   796 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   797 run both "isabelle" and "Isabelle" even if file names are badly
   798 damaged (executable inspects the case of the first letter of its own
   799 name); added separate "isabelle-process" and "isabelle-interface";
   800 
   801 * system: refrain from any attempt at filtering input streams; no
   802 longer support ``8bit'' encoding of old isabelle font, instead proper
   803 iso-latin characters may now be used; the related isatools
   804 "symbolinput" and "nonascii" have disappeared as well;
   805 
   806 * system: removed old "xterm" interface (the print modes "xterm" and
   807 "xterm_color" are still available for direct use in a suitable
   808 terminal);
   809 
   810 
   811 
   812 New in Isabelle99-2 (February 2001)
   813 -----------------------------------
   814 
   815 *** Overview of INCOMPATIBILITIES ***
   816 
   817 * HOL: please note that theories in the Library and elsewhere often use the
   818 new-style (Isar) format; to refer to their theorems in an ML script you must
   819 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   820 
   821 * HOL: inductive package no longer splits induction rule aggressively,
   822 but only as far as specified by the introductions given; the old
   823 format may be recovered via ML function complete_split_rule or attribute
   824 'split_rule (complete)';
   825 
   826 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   827 gfp_Tarski to gfp_unfold;
   828 
   829 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   830 
   831 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   832 relation); infix "^^" has been renamed "``"; infix "``" has been
   833 renamed "`"; "univalent" has been renamed "single_valued";
   834 
   835 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   836 operation;
   837 
   838 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   839 
   840 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   841 
   842 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   843 consequence, it is no longer monotonic wrt. the local goal context
   844 (which is now passed through the inductive cases);
   845 
   846 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   847 \<gg> to \<ggreater>;
   848 
   849 
   850 *** Document preparation ***
   851 
   852 * \isabellestyle{NAME} selects version of Isabelle output (currently
   853 available: are "it" for near math-mode best-style output, "sl" for
   854 slanted text style, and "tt" for plain type-writer; if no
   855 \isabellestyle command is given, output is according to slanted
   856 type-writer);
   857 
   858 * support sub/super scripts (for single symbols only), input syntax is
   859 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   860 
   861 * some more standard symbols; see Appendix A of the system manual for
   862 the complete list of symbols defined in isabellesym.sty;
   863 
   864 * improved isabelle style files; more abstract symbol implementation
   865 (should now use \isamath{...} and \isatext{...} in custom symbol
   866 definitions);
   867 
   868 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   869 state; Note that presentation of goal states does not conform to
   870 actual human-readable proof documents.  Please do not include goal
   871 states into document output unless you really know what you are doing!
   872 
   873 * proper indentation of antiquoted output with proportional LaTeX
   874 fonts;
   875 
   876 * no_document ML operator temporarily disables LaTeX document
   877 generation;
   878 
   879 * isatool unsymbolize tunes sources for plain ASCII communication;
   880 
   881 
   882 *** Isar ***
   883 
   884 * Pure: Isar now suffers initial goal statements to contain unbound
   885 schematic variables (this does not conform to actual readable proof
   886 documents, due to unpredictable outcome and non-compositional proof
   887 checking); users who know what they are doing may use schematic goals
   888 for Prolog-style synthesis of proven results;
   889 
   890 * Pure: assumption method (an implicit finishing) now handles actual
   891 rules as well;
   892 
   893 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   894 initial goal, declare "that" only as Pure intro (only for single
   895 steps); the "that" rule assumption may now be involved in implicit
   896 finishing, thus ".." becomes a feasible for trivial obtains;
   897 
   898 * Pure: default proof step now includes 'intro_classes'; thus trivial
   899 instance proofs may be performed by "..";
   900 
   901 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   902 statements as well;
   903 
   904 * Pure: more robust selection of calculational rules;
   905 
   906 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   907 rule (as well as the assumption rule);
   908 
   909 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   910 lemmas, using the graph browser tool;
   911 
   912 * Pure: predict failure of "show" in interactive mode;
   913 
   914 * Pure: 'thms_containing' now takes actual terms as arguments;
   915 
   916 * HOL: improved method 'induct' --- now handles non-atomic goals
   917 (potential INCOMPATIBILITY); tuned error handling;
   918 
   919 * HOL: cases and induct rules now provide explicit hints about the
   920 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   921 any remaining facts are inserted into the goal verbatim;
   922 
   923 * HOL: local contexts (aka cases) may now contain term bindings as
   924 well; the 'cases' and 'induct' methods new provide a ?case binding for
   925 the result to be shown in each case;
   926 
   927 * HOL: added 'recdef_tc' command;
   928 
   929 * isatool convert assists in eliminating legacy ML scripts;
   930 
   931 
   932 *** HOL ***
   933 
   934 * HOL/Library: a collection of generic theories to be used together
   935 with main HOL; the theory loader path already includes this directory
   936 by default; the following existing theories have been moved here:
   937 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   938 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   939 
   940 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   941 modelling and verification task performed in Isabelle/HOL +
   942 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   943 
   944 * HOL/Algebra: special summation operator SUM no longer exists, it has
   945 been replaced by setsum; infix 'assoc' now has priority 50 (like
   946 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   947 'domain', this makes the theory consistent with mathematical
   948 literature;
   949 
   950 * HOL basics: added overloaded operations "inverse" and "divide"
   951 (infix "/"), syntax for generic "abs" operation, generic summation
   952 operator \<Sum>;
   953 
   954 * HOL/typedef: simplified package, provide more useful rules (see also
   955 HOL/subset.thy);
   956 
   957 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   958 now expressed as a proper nested rule (old-style tactic scripts may
   959 require atomize_strip_tac to cope with non-atomic premises);
   960 
   961 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   962 to "split_conv" (old name still available for compatibility);
   963 
   964 * HOL: improved concrete syntax for strings (e.g. allows translation
   965 rules with string literals);
   966 
   967 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   968  and Fleuriot's mechanization of analysis, including the transcendental
   969  functions for the reals;
   970 
   971 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   972 
   973 
   974 *** CTT ***
   975 
   976 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   977 "lam" is displayed as TWO lambda-symbols
   978 
   979 * CTT: theory Main now available, containing everything (that is, Bool
   980 and Arith);
   981 
   982 
   983 *** General ***
   984 
   985 * Pure: the Simplifier has been implemented properly as a derived rule
   986 outside of the actual kernel (at last!); the overall performance
   987 penalty in practical applications is about 50%, while reliability of
   988 the Isabelle inference kernel has been greatly improved;
   989 
   990 * print modes "brackets" and "no_brackets" control output of nested =>
   991 (types) and ==> (props); the default behaviour is "brackets";
   992 
   993 * Provers: fast_tac (and friends) now handle actual object-logic rules
   994 as assumptions as well;
   995 
   996 * system: support Poly/ML 4.0;
   997 
   998 * system: isatool install handles KDE version 1 or 2;
   999 
  1000 
  1001 
  1002 New in Isabelle99-1 (October 2000)
  1003 ----------------------------------
  1004 
  1005 *** Overview of INCOMPATIBILITIES ***
  1006 
  1007 * HOL: simplification of natural numbers is much changed; to partly
  1008 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1009 issue the following ML commands:
  1010 
  1011   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1012   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1013 
  1014 * HOL: simplification no longer dives into case-expressions; this is
  1015 controlled by "t.weak_case_cong" for each datatype t;
  1016 
  1017 * HOL: nat_less_induct renamed to less_induct;
  1018 
  1019 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1020 fixsome to patch .thy and .ML sources automatically;
  1021 
  1022   select_equality  -> some_equality
  1023   select_eq_Ex     -> some_eq_ex
  1024   selectI2EX       -> someI2_ex
  1025   selectI2         -> someI2
  1026   selectI          -> someI
  1027   select1_equality -> some1_equality
  1028   Eps_sym_eq       -> some_sym_eq_trivial
  1029   Eps_eq           -> some_eq_trivial
  1030 
  1031 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1032 
  1033 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1034 instead);
  1035 
  1036 * HOL: the recursion equations generated by 'recdef' are now called
  1037 f.simps instead of f.rules;
  1038 
  1039 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1040 
  1041 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1042 sometimes be needed;
  1043 
  1044 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1045 
  1046 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1047 
  1048 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1049 product is now "<*>" instead of "Times"; the lexicographic product is
  1050 now "<*lex*>" instead of "**";
  1051 
  1052 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1053 of main HOL, but was unused); better use HOL's datatype package;
  1054 
  1055 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1056 the old syntax may be recovered as follows:
  1057 
  1058   syntax (symbols)
  1059     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1060       (infixl "\\<oplus>" 100)
  1061 
  1062 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1063 
  1064 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1065 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1066 internally;
  1067 
  1068 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1069 changed from A/r to A//r;
  1070 
  1071 * ZF: new treatment of arithmetic (nat & int) may break some old
  1072 proofs;
  1073 
  1074 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1075 rulify -> rule_format, elimify -> elim_format, ...);
  1076 
  1077 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1078 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1079 should have to change intro!! to intro? only); replaced "delrule" by
  1080 "rule del";
  1081 
  1082 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1083 
  1084 * Provers: strengthened force_tac by using new first_best_tac;
  1085 
  1086 * LaTeX document preparation: several changes of isabelle.sty (see
  1087 lib/texinputs);
  1088 
  1089 
  1090 *** Document preparation ***
  1091 
  1092 * formal comments (text blocks etc.) in new-style theories may now
  1093 contain antiquotations of thm/prop/term/typ/text to be presented
  1094 according to latex print mode; concrete syntax is like this:
  1095 @{term[show_types] "f(x) = a + x"};
  1096 
  1097 * isatool mkdir provides easy setup of Isabelle session directories,
  1098 including proper document sources;
  1099 
  1100 * generated LaTeX sources are now deleted after successful run
  1101 (isatool document -c); may retain a copy somewhere else via -D option
  1102 of isatool usedir;
  1103 
  1104 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1105 style files, achieving self-contained LaTeX sources and simplifying
  1106 LaTeX debugging;
  1107 
  1108 * old-style theories now produce (crude) LaTeX output as well;
  1109 
  1110 * browser info session directories are now self-contained (may be put
  1111 on WWW server seperately); improved graphs of nested sessions; removed
  1112 graph for 'all sessions';
  1113 
  1114 * several improvements in isabelle style files; \isabellestyle{it}
  1115 produces fake math mode output; \isamarkupheader is now \section by
  1116 default; see lib/texinputs/isabelle.sty etc.;
  1117 
  1118 
  1119 *** Isar ***
  1120 
  1121 * Isar/Pure: local results and corresponding term bindings are now
  1122 subject to Hindley-Milner polymorphism (similar to ML); this
  1123 accommodates incremental type-inference very nicely;
  1124 
  1125 * Isar/Pure: new derived language element 'obtain' supports
  1126 generalized existence reasoning;
  1127 
  1128 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1129 support accumulation of results, without applying any rules yet;
  1130 useful to collect intermediate results without explicit name
  1131 references, and for use with transitivity rules with more than 2
  1132 premises;
  1133 
  1134 * Isar/Pure: scalable support for case-analysis type proofs: new
  1135 'case' language element refers to local contexts symbolically, as
  1136 produced by certain proof methods; internally, case names are attached
  1137 to theorems as "tags";
  1138 
  1139 * Isar/Pure: theory command 'hide' removes declarations from
  1140 class/type/const name spaces;
  1141 
  1142 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1143 indicate potential overloading;
  1144 
  1145 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1146 
  1147 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1148 "{a,b,c}" instead of {a,b,c};
  1149 
  1150 * Isar/Pure now provides its own version of intro/elim/dest
  1151 attributes; useful for building new logics, but beware of confusion
  1152 with the version in Provers/classical;
  1153 
  1154 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1155 case name 'antecedent';
  1156 
  1157 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1158 to the current context is now done automatically);
  1159 
  1160 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1161 for definining proof methods in ML;
  1162 
  1163 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1164 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1165 most cases, one should have to change intro!! to intro? only);
  1166 replaced "delrule" by "rule del";
  1167 
  1168 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1169 'symmetric' attribute (the latter supercedes [RS sym]);
  1170 
  1171 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1172 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1173 well (including splits);
  1174 
  1175 * Isar/Provers: Simplifier and Classical methods now support all kind
  1176 of modifiers used in the past, including 'cong', 'iff', etc.
  1177 
  1178 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1179 of Simplifier and Classical reasoner);
  1180 
  1181 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1182 now support named cases; major packages (inductive, datatype, primrec,
  1183 recdef) support case names and properly name parameters;
  1184 
  1185 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1186 monotonicity conditions are extracted to be proven at end of
  1187 calculations;
  1188 
  1189 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1190 method anyway;
  1191 
  1192 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1193 split_if split_if_asm; datatype package provides theorems foo.splits =
  1194 foo.split foo.split_asm for each datatype;
  1195 
  1196 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1197 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1198 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1199 use "(cases (simplified))" method in proper proof texts);
  1200 
  1201 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1202 
  1203 * Isar: names of theorems etc. may be natural numbers as well;
  1204 
  1205 * Isar: 'pr' command: optional arguments for goals_limit and
  1206 ProofContext.prems_limit; no longer prints theory contexts, but only
  1207 proof states;
  1208 
  1209 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1210 additional print modes to be specified; e.g. "pr(latex)" will print
  1211 proof state according to the Isabelle LaTeX style;
  1212 
  1213 * Isar: improved support for emulating tactic scripts, including proof
  1214 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1215 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1216 (for HOL datatypes);
  1217 
  1218 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1219 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1220 'proof method scripts' have to be in depth-first order;
  1221 
  1222 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1223 
  1224 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1225 should instead use individual commands for printing items
  1226 (print_commands, print_methods etc.);
  1227 
  1228 * Isar: added 'nothing' --- the empty list of theorems;
  1229 
  1230 
  1231 *** HOL ***
  1232 
  1233 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1234 corresponding virtual machine and a specification of its bytecode
  1235 verifier and a lightweight bytecode verifier, including proofs of
  1236 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1237 Cornelia Pusch (see also the homepage of project Bali at
  1238 http://isabelle.in.tum.de/Bali/);
  1239 
  1240 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1241 Clemens Ballarin;
  1242 
  1243 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1244 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1245 Rasmussen;
  1246 
  1247 * HOL/Lattice: fundamental concepts of lattice theory and order
  1248 structures, including duals, properties of bounds versus algebraic
  1249 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1250 Theorem for complete lattices etc.; may also serve as a demonstration
  1251 for abstract algebraic reasoning using axiomatic type classes, and
  1252 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1253 
  1254 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1255 von Oheimb;
  1256 
  1257 * HOL/IMPP: extension of IMP with local variables and mutually
  1258 recursive procedures, by David von Oheimb;
  1259 
  1260 * HOL/Lambda: converted into new-style theory and document;
  1261 
  1262 * HOL/ex/Multiquote: example of multiple nested quotations and
  1263 anti-quotations -- basically a generalized version of de-Bruijn
  1264 representation; very useful in avoiding lifting of operations;
  1265 
  1266 * HOL/record: added general record equality rule to simpset; fixed
  1267 select-update simplification procedure to handle extended records as
  1268 well; admit "r" as field name;
  1269 
  1270 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1271 other numeric types and also as the identity of groups, rings, etc.;
  1272 
  1273 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1274 Types nat and int belong to this axclass;
  1275 
  1276 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1277    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1278    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1279   two terms #m*u and #n*u are replaced by #(m+n)*u
  1280     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1281   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1282     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1283 
  1284 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1285 powerful prover for predicate logic but knows nothing of clasets; see
  1286 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1287 
  1288 * HOL: new version of "case_tac" subsumes both boolean case split and
  1289 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1290 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1291 
  1292 * HOL: simplification no longer dives into case-expressions: only the
  1293 selector expression is simplified, but not the remaining arms; to
  1294 enable full simplification of case-expressions for datatype t, you may
  1295 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1296 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1297 
  1298 * HOL/recdef: the recursion equations generated by 'recdef' for
  1299 function 'f' are now called f.simps instead of f.rules; if all
  1300 termination conditions are proved automatically, these simplification
  1301 rules are added to the simpset, as in primrec; rules may be named
  1302 individually as well, resulting in a separate list of theorems for
  1303 each equation;
  1304 
  1305 * HOL/While is a new theory that provides a while-combinator. It
  1306 permits the definition of tail-recursive functions without the
  1307 provision of a termination measure. The latter is necessary once the
  1308 invariant proof rule for while is applied.
  1309 
  1310 * HOL: new (overloaded) notation for the set of elements below/above
  1311 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1312 
  1313 * HOL: theorems impI, allI, ballI bound as "strip";
  1314 
  1315 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1316 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1317 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1318 
  1319 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1320 
  1321 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1322 main HOL, but was unused);
  1323 
  1324 * HOL: fewer consts declared as global (e.g. have to refer to
  1325 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1326 
  1327 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1328 in case of overlap with user translations (e.g. judgements over
  1329 tuples); (note that the underlying logical represenation is still
  1330 bogus);
  1331 
  1332 
  1333 *** ZF ***
  1334 
  1335 * ZF: simplification automatically cancels common terms in arithmetic
  1336 expressions over nat and int;
  1337 
  1338 * ZF: new treatment of nat to minimize type-checking: all operators
  1339 coerce their operands to a natural number using the function natify,
  1340 making the algebraic laws unconditional;
  1341 
  1342 * ZF: as above, for int: operators coerce their operands to an integer
  1343 using the function intify;
  1344 
  1345 * ZF: the integer library now contains many of the usual laws for the
  1346 orderings, including $<=, and monotonicity laws for $+ and $*;
  1347 
  1348 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1349 simplification;
  1350 
  1351 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1352 to the simplifier and classical reasoner simultaneously;
  1353 
  1354 
  1355 *** General ***
  1356 
  1357 * Provers: blast_tac now handles actual object-logic rules as
  1358 assumptions; note that auto_tac uses blast_tac internally as well;
  1359 
  1360 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1361 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1362 
  1363 * Provers: delrules now handles destruct rules as well (no longer need
  1364 explicit make_elim);
  1365 
  1366 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1367   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1368 use instead the strong form,
  1369   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1370 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1371 from destruct-rules;
  1372 
  1373 * Provers: Simplifier.easy_setup provides a fast path to basic
  1374 Simplifier setup for new object-logics;
  1375 
  1376 * Pure: AST translation rules no longer require constant head on LHS;
  1377 
  1378 * Pure: improved name spaces: ambiguous output is qualified; support
  1379 for hiding of names;
  1380 
  1381 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1382 XSYMBOL_HOME; no longer need to do manual configuration in most
  1383 situations;
  1384 
  1385 * system: compression of ML heaps images may now be controlled via -c
  1386 option of isabelle and isatool usedir (currently only observed by
  1387 Poly/ML);
  1388 
  1389 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1390 useful for remote X11);
  1391 
  1392 * system: provide TAGS file for Isabelle sources;
  1393 
  1394 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1395 order;
  1396 
  1397 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1398 timing flag supersedes proof_timing and Toplevel.trace;
  1399 
  1400 * ML: new combinators |>> and |>>> for incremental transformations
  1401 with secondary results (e.g. certain theory extensions):
  1402 
  1403 * ML: PureThy.add_defs gets additional argument to indicate potential
  1404 overloading (usually false);
  1405 
  1406 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1407 results;
  1408 
  1409 
  1410 
  1411 New in Isabelle99 (October 1999)
  1412 --------------------------------
  1413 
  1414 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1415 
  1416 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1417 are no longer simplified.  (This allows the simplifier to unfold recursive
  1418 functional programs.)  To restore the old behaviour, declare
  1419 
  1420     Delcongs [if_weak_cong];
  1421 
  1422 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1423 complement;
  1424 
  1425 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1426 
  1427 * HOL/datatype: mutual_induct_tac no longer exists --
  1428   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1429 
  1430 * HOL/typedef: fixed type inference for representing set; type
  1431 arguments now have to occur explicitly on the rhs as type constraints;
  1432 
  1433 * ZF: The con_defs part of an inductive definition may no longer refer
  1434 to constants declared in the same theory;
  1435 
  1436 * HOL, ZF: the function mk_cases, generated by the inductive
  1437 definition package, has lost an argument.  To simplify its result, it
  1438 uses the default simpset instead of a supplied list of theorems.
  1439 
  1440 * HOL/List: the constructors of type list are now Nil and Cons;
  1441 
  1442 * Simplifier: the type of the infix ML functions
  1443         setSSolver addSSolver setSolver addSolver
  1444 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1445 for packaging solvers. A solver is created via
  1446         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1447 where the string argument is only a comment.
  1448 
  1449 
  1450 *** Proof tools ***
  1451 
  1452 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1453 decision procedure for linear arithmetic. Currently it is used for
  1454 types `nat', `int', and `real' in HOL (see below); it can, should and
  1455 will be instantiated for other types and logics as well.
  1456 
  1457 * The simplifier now accepts rewrite rules with flexible heads, eg
  1458      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1459   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1460   matching.
  1461 
  1462 
  1463 *** General ***
  1464 
  1465 * New Isabelle/Isar subsystem provides an alternative to traditional
  1466 tactical theorem proving; together with the ProofGeneral/isar user
  1467 interface it offers an interactive environment for developing human
  1468 readable proof documents (Isar == Intelligible semi-automated
  1469 reasoning); for further information see isatool doc isar-ref,
  1470 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1471 
  1472 * improved and simplified presentation of theories: better HTML markup
  1473 (including colors), graph views in several sizes; isatool usedir now
  1474 provides a proper interface for user theories (via -P option); actual
  1475 document preparation based on (PDF)LaTeX is available as well (for
  1476 new-style theories only); see isatool doc system for more information;
  1477 
  1478 * native support for Proof General, both for classic Isabelle and
  1479 Isabelle/Isar;
  1480 
  1481 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1482 using the graph browser tool;
  1483 
  1484 * Isabelle manuals now also available as PDF;
  1485 
  1486 * theory loader rewritten from scratch (may not be fully
  1487 bug-compatible); old loadpath variable has been replaced by show_path,
  1488 add_path, del_path, reset_path functions; new operations such as
  1489 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1490 isatool doc ref);
  1491 
  1492 * improved isatool install: option -k creates KDE application icon,
  1493 option -p DIR installs standalone binaries;
  1494 
  1495 * added ML_PLATFORM setting (useful for cross-platform installations);
  1496 more robust handling of platform specific ML images for SML/NJ;
  1497 
  1498 * the settings environment is now statically scoped, i.e. it is never
  1499 created again in sub-processes invoked from isabelle, isatool, or
  1500 Isabelle;
  1501 
  1502 * path element specification '~~' refers to '$ISABELLE_HOME';
  1503 
  1504 * in locales, the "assumes" and "defines" parts may be omitted if
  1505 empty;
  1506 
  1507 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1508 long arrows);
  1509 
  1510 * new print_mode "HTML";
  1511 
  1512 * new flag show_tags controls display of tags of theorems (which are
  1513 basically just comments that may be attached by some tools);
  1514 
  1515 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1516 mode and goal output format:
  1517 
  1518 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1519 244c244
  1520 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1521 ---
  1522 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1523 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1524 181c181
  1525 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1526 ---
  1527 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1528 
  1529 * function bind_thms stores lists of theorems (cf. bind_thm);
  1530 
  1531 * new shorthand tactics ftac, eatac, datac, fatac;
  1532 
  1533 * qed (and friends) now accept "" as result name; in that case the
  1534 theorem is not stored, but proper checks and presentation of the
  1535 result still apply;
  1536 
  1537 * theorem database now also indexes constants "Trueprop", "all",
  1538 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1539 
  1540 
  1541 *** HOL ***
  1542 
  1543 ** HOL arithmetic **
  1544 
  1545 * There are now decision procedures for linear arithmetic over nat and
  1546 int:
  1547 
  1548 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1549 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1550 are treated as atomic; subformulae not involving type `nat' or `int'
  1551 are ignored; quantified subformulae are ignored unless they are
  1552 positive universal or negative existential. The tactic has to be
  1553 invoked by hand and can be a little bit slow. In particular, the
  1554 running time is exponential in the number of occurrences of `min' and
  1555 `max', and `-' on `nat'.
  1556 
  1557 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1558 (negated) (in)equalities among the premises and the conclusion into
  1559 account (i.e. no compound formulae) and does not know about `min' and
  1560 `max', and `-' on `nat'. It is fast and is used automatically by the
  1561 simplifier.
  1562 
  1563 NB: At the moment, these decision procedures do not cope with mixed
  1564 nat/int formulae where the two parts interact, such as `m < n ==>
  1565 int(m) < int(n)'.
  1566 
  1567 * HOL/Numeral provides a generic theory of numerals (encoded
  1568 efficiently as bit strings); setup for types nat/int/real is in place;
  1569 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1570 int, existing theories and proof scripts may require a few additional
  1571 type constraints;
  1572 
  1573 * integer division and remainder can now be performed on constant
  1574 arguments;
  1575 
  1576 * many properties of integer multiplication, division and remainder
  1577 are now available;
  1578 
  1579 * An interface to the Stanford Validity Checker (SVC) is available through the
  1580 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1581 are proved automatically.  SVC must be installed separately, and its results
  1582 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1583 invocation of the underlying oracle).  For SVC see
  1584   http://verify.stanford.edu/SVC
  1585 
  1586 * IsaMakefile: the HOL-Real target now builds an actual image;
  1587 
  1588 
  1589 ** HOL misc **
  1590 
  1591 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1592 (in Isabelle/Isar) -- by Gertrud Bauer;
  1593 
  1594 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1595 analysis for assembly languages with subtypes;
  1596 
  1597 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1598 -- avoids syntactic ambiguities and treats state, transition, and
  1599 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1600 changed syntax and (many) tactics;
  1601 
  1602 * HOL/inductive: Now also handles more general introduction rules such
  1603   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1604   theorems are now maintained within the theory (maintained via the
  1605   "mono" attribute);
  1606 
  1607 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1608   (using function types) such as
  1609 
  1610   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1611 
  1612 * HOL/record: record_simproc (part of the default simpset) takes care
  1613 of selectors applied to updated records; record_split_tac is no longer
  1614 part of the default claset; update_defs may now be removed from the
  1615 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1616 
  1617   claset_ref () := claset() addSWrapper record_split_wrapper;
  1618   Delsimprocs [record_simproc]
  1619 
  1620 * HOL/typedef: fixed type inference for representing set; type
  1621 arguments now have to occur explicitly on the rhs as type constraints;
  1622 
  1623 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1624 names rather than an ML expression;
  1625 
  1626 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1627 supplied later.  Program schemes can be defined, such as
  1628     "While B C s = (if B s then While B C (C s) else s)"
  1629 where the well-founded relation can be chosen after B and C have been given.
  1630 
  1631 * HOL/List: the constructors of type list are now Nil and Cons;
  1632 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1633 course, ML tools referring to List.list.op # etc. have to be adapted;
  1634 
  1635 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1636 disabled by default; run isabelle with option -m HOL to get back to
  1637 the original Gordon/HOL-style output;
  1638 
  1639 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1640 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1641 
  1642 * HOL basic syntax simplified (more orthogonal): all variants of
  1643 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1644 Eps operator is provided as well: "SOME x. P[x]";
  1645 
  1646 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1647 
  1648 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1649 thus available for user theories;
  1650 
  1651 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1652 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1653 time;
  1654 
  1655 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1656 several times and then mp;
  1657 
  1658 
  1659 *** LK ***
  1660 
  1661 * the notation <<...>> is now available as a notation for sequences of
  1662 formulas;
  1663 
  1664 * the simplifier is now installed
  1665 
  1666 * the axiom system has been generalized (thanks to Soren Heilmann)
  1667 
  1668 * the classical reasoner now has a default rule database
  1669 
  1670 
  1671 *** ZF ***
  1672 
  1673 * new primrec section allows primitive recursive functions to be given
  1674 directly (as in HOL) over datatypes and the natural numbers;
  1675 
  1676 * new tactics induct_tac and exhaust_tac for induction (or case
  1677 analysis) over datatypes and the natural numbers;
  1678 
  1679 * the datatype declaration of type T now defines the recursor T_rec;
  1680 
  1681 * simplification automatically does freeness reasoning for datatype
  1682 constructors;
  1683 
  1684 * automatic type-inference, with AddTCs command to insert new
  1685 type-checking rules;
  1686 
  1687 * datatype introduction rules are now added as Safe Introduction rules
  1688 to the claset;
  1689 
  1690 * the syntax "if P then x else y" is now available in addition to
  1691 if(P,x,y);
  1692 
  1693 
  1694 *** Internal programming interfaces ***
  1695 
  1696 * tuned simplifier trace output; new flag debug_simp;
  1697 
  1698 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1699 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1700 
  1701 * AxClass.axclass_tac lost the theory argument;
  1702 
  1703 * tuned current_goals_markers semantics: begin / end goal avoids
  1704 printing empty lines;
  1705 
  1706 * removed prs and prs_fn hook, which was broken because it did not
  1707 include \n in its semantics, forcing writeln to add one
  1708 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1709 string -> unit if you really want to output text without newline;
  1710 
  1711 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1712 plain output, interface builders may have to enable 'isabelle_font'
  1713 mode to get Isabelle font glyphs as before;
  1714 
  1715 * refined token_translation interface; INCOMPATIBILITY: output length
  1716 now of type real instead of int;
  1717 
  1718 * theory loader actions may be traced via new ThyInfo.add_hook
  1719 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1720 your own database of information attached to *whole* theories -- as
  1721 opposed to intra-theory data slots offered via TheoryDataFun;
  1722 
  1723 * proper handling of dangling sort hypotheses (at last!);
  1724 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1725 extra sort hypotheses that can be witnessed from the type signature;
  1726 the force_strip_shyps flag is gone, any remaining shyps are simply
  1727 left in the theorem (with a warning issued by strip_shyps_warning);
  1728 
  1729 
  1730 
  1731 New in Isabelle98-1 (October 1998)
  1732 ----------------------------------
  1733 
  1734 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1735 
  1736 * several changes of automated proof tools;
  1737 
  1738 * HOL: major changes to the inductive and datatype packages, including
  1739 some minor incompatibilities of theory syntax;
  1740 
  1741 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1742 called `inj_on';
  1743 
  1744 * HOL: removed duplicate thms in Arith:
  1745   less_imp_add_less  should be replaced by  trans_less_add1
  1746   le_imp_add_le      should be replaced by  trans_le_add1
  1747 
  1748 * HOL: unary minus is now overloaded (new type constraints may be
  1749 required);
  1750 
  1751 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1752 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1753 now taken as an integer constant.
  1754 
  1755 * Pure: ML function 'theory_of' renamed to 'theory';
  1756 
  1757 
  1758 *** Proof tools ***
  1759 
  1760 * Simplifier:
  1761   1. Asm_full_simp_tac is now more aggressive.
  1762      1. It will sometimes reorient premises if that increases their power to
  1763         simplify.
  1764      2. It does no longer proceed strictly from left to right but may also
  1765         rotate premises to achieve further simplification.
  1766      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1767      old Asm_full_simp_tac in that it does not rotate premises.
  1768   2. The simplifier now knows a little bit about nat-arithmetic.
  1769 
  1770 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1771 allows for selected deletion of wrappers, by introduction of names for
  1772 wrapper functionals.  This implies that addbefore, addSbefore,
  1773 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1774 and that adding two tactics with the same name overwrites the first
  1775 one (emitting a warning).
  1776   type wrapper = (int -> tactic) -> (int -> tactic)
  1777   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1778   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1779   delWrapper, delSWrapper: claset *  string            -> claset
  1780   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1781 
  1782 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1783 semantics; addbefore now affects only the unsafe part of step_tac
  1784 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1785 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1786 by Force_tac;
  1787 
  1788 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1789 compWrapper; added safe wrapper (and access functions for it);
  1790 
  1791 * HOL/split_all_tac is now much faster and fails if there is nothing
  1792 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1793 and the names of the automatically generated variables have changed.
  1794 split_all_tac has moved within claset() from unsafe wrappers to safe
  1795 wrappers, which means that !!-bound variables are split much more
  1796 aggressively, and safe_tac and clarify_tac now split such variables.
  1797 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1798 Note: the same holds for record_split_tac, which does the job of
  1799 split_all_tac for record fields.
  1800 
  1801 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1802 permanently to the default simpset using Addsplits just like
  1803 Addsimps. They can be removed via Delsplits just like
  1804 Delsimps. Lower-case versions are also available.
  1805 
  1806 * HOL/Simplifier: The rule split_if is now part of the default
  1807 simpset. This means that the simplifier will eliminate all occurrences
  1808 of if-then-else in the conclusion of a goal. To prevent this, you can
  1809 either remove split_if completely from the default simpset by
  1810 `Delsplits [split_if]' or remove it in a specific call of the
  1811 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1812 other case splitting rules to/from the default simpset: every datatype
  1813 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1814 t is the name of the datatype).
  1815 
  1816 * Classical reasoner / Simplifier combination: new force_tac (and
  1817 derivatives Force_tac, force) combines rewriting and classical
  1818 reasoning (and whatever other tools) similarly to auto_tac, but is
  1819 aimed to solve the given subgoal completely.
  1820 
  1821 
  1822 *** General ***
  1823 
  1824 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1825 and `goalw': the theory is no longer needed as an explicit argument -
  1826 the current theory context is used; assumptions are no longer returned
  1827 at the ML-level unless one of them starts with ==> or !!; it is
  1828 recommended to convert to these new commands using isatool fixgoal
  1829 (backup your sources first!);
  1830 
  1831 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1832 the current theory context, and 'theory' to lookup stored theories;
  1833 
  1834 * new theory section 'locale' for declaring constants, assumptions and
  1835 definitions that have local scope;
  1836 
  1837 * new theory section 'nonterminals' for purely syntactic types;
  1838 
  1839 * new theory section 'setup' for generic ML setup functions
  1840 (e.g. package initialization);
  1841 
  1842 * the distribution now includes Isabelle icons: see
  1843 lib/logo/isabelle-{small,tiny}.xpm;
  1844 
  1845 * isatool install - install binaries with absolute references to
  1846 ISABELLE_HOME/bin;
  1847 
  1848 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1849 
  1850 * print mode 'emacs' reserved for Isamode;
  1851 
  1852 * support multiple print (ast) translations per constant name;
  1853 
  1854 * theorems involving oracles are now printed with a suffixed [!];
  1855 
  1856 
  1857 *** HOL ***
  1858 
  1859 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1860 
  1861 * HOL/inductive package reorganized and improved: now supports mutual
  1862 definitions such as
  1863 
  1864   inductive EVEN ODD
  1865     intrs
  1866       null "0 : EVEN"
  1867       oddI "n : EVEN ==> Suc n : ODD"
  1868       evenI "n : ODD ==> Suc n : EVEN"
  1869 
  1870 new theorem list "elims" contains an elimination rule for each of the
  1871 recursive sets; inductive definitions now handle disjunctive premises
  1872 correctly (also ZF);
  1873 
  1874 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1875 "mutual_induct" no longer exists - the induction rule is always
  1876 contained in "induct";
  1877 
  1878 
  1879 * HOL/datatype package re-implemented and greatly improved: now
  1880 supports mutually recursive datatypes such as
  1881 
  1882   datatype
  1883     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1884             | SUM ('a aexp) ('a aexp)
  1885             | DIFF ('a aexp) ('a aexp)
  1886             | NUM 'a
  1887   and
  1888     'a bexp = LESS ('a aexp) ('a aexp)
  1889             | AND ('a bexp) ('a bexp)
  1890             | OR ('a bexp) ('a bexp)
  1891 
  1892 as well as indirectly recursive datatypes such as
  1893 
  1894   datatype
  1895     ('a, 'b) term = Var 'a
  1896                   | App 'b ((('a, 'b) term) list)
  1897 
  1898 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1899 induction on mutually / indirectly recursive datatypes.
  1900 
  1901 Primrec equations are now stored in theory and can be accessed via
  1902 <function_name>.simps.
  1903 
  1904 INCOMPATIBILITIES:
  1905 
  1906   - Theories using datatypes must now have theory Datatype as an
  1907     ancestor.
  1908   - The specific <typename>.induct_tac no longer exists - use the
  1909     generic induct_tac instead.
  1910   - natE has been renamed to nat.exhaust - use exhaust_tac
  1911     instead of res_inst_tac ... natE. Note that the variable
  1912     names in nat.exhaust differ from the names in natE, this
  1913     may cause some "fragile" proofs to fail.
  1914   - The theorems split_<typename>_case and split_<typename>_case_asm
  1915     have been renamed to <typename>.split and <typename>.split_asm.
  1916   - Since default sorts of type variables are now handled correctly,
  1917     some datatype definitions may have to be annotated with explicit
  1918     sort constraints.
  1919   - Primrec definitions no longer require function name and type
  1920     of recursive argument.
  1921 
  1922 Consider using isatool fixdatatype to adapt your theories and proof
  1923 scripts to the new package (backup your sources first!).
  1924 
  1925 
  1926 * HOL/record package: considerably improved implementation; now
  1927 includes concrete syntax for record types, terms, updates; theorems
  1928 for surjective pairing and splitting !!-bound record variables; proof
  1929 support is as follows:
  1930 
  1931   1) standard conversions (selectors or updates applied to record
  1932 constructor terms) are part of the standard simpset;
  1933 
  1934   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1935 made part of standard simpset and claset via addIffs;
  1936 
  1937   3) a tactic for record field splitting (record_split_tac) is part of
  1938 the standard claset (addSWrapper);
  1939 
  1940 To get a better idea about these rules you may retrieve them via
  1941 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1942 the name of your record type.
  1943 
  1944 The split tactic 3) conceptually simplifies by the following rule:
  1945 
  1946   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1947 
  1948 Thus any record variable that is bound by meta-all will automatically
  1949 blow up into some record constructor term, consequently the
  1950 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1951 solve record problems automatically.
  1952 
  1953 
  1954 * reorganized the main HOL image: HOL/Integ and String loaded by
  1955 default; theory Main includes everything;
  1956 
  1957 * automatic simplification of integer sums and comparisons, using cancellation;
  1958 
  1959 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1960 
  1961 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1962 
  1963 * many new identities for unions, intersections, set difference, etc.;
  1964 
  1965 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1966 called split_if, split_split, split_sum_case and split_nat_case (to go
  1967 with add/delsplits);
  1968 
  1969 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1970 (?x::unit) = (); this is made part of the default simpset, which COULD
  1971 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1972 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1973 unit_abs_eta_conv is added in order to counter the effect of
  1974 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1975 %u.f();
  1976 
  1977 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1978 makes more sense);
  1979 
  1980 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1981   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1982   disjointness reasoning but breaking a few old proofs.
  1983 
  1984 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1985 to 'converse' from 'inverse' (for compatibility with ZF and some
  1986 literature);
  1987 
  1988 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1989 the well-founded relation;
  1990 
  1991 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1992     Compl A.  The "Compl" syntax remains available as input syntax for this
  1993     release ONLY.
  1994 
  1995 * HOL/Update: new theory of function updates:
  1996     f(a:=b) == %x. if x=a then b else f x
  1997 may also be iterated as in f(a:=b,c:=d,...);
  1998 
  1999 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2000 
  2001 * HOL/List:
  2002   - new function list_update written xs[i:=v] that updates the i-th
  2003     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2004   - new function `upt' written [i..j(] which generates the list
  2005     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2006     bound write [i..j], which is a shorthand for [i..j+1(].
  2007   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2008 
  2009 * HOL/Arith:
  2010   - removed 'pred' (predecessor) function;
  2011   - generalized some theorems about n-1;
  2012   - many new laws about "div" and "mod";
  2013   - new laws about greatest common divisors (see theory ex/Primes);
  2014 
  2015 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2016 instead of "inverse";
  2017 
  2018 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2019   of the multiset ordering;
  2020 
  2021 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2022   (not included by default);
  2023 
  2024 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2025 
  2026 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2027   programs, i.e. different program variables may have different types.
  2028 
  2029 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2030   [previously, this check worked only if the rewrite rule was unconditional]
  2031   Now rew can involve either definitions or equalities (either == or =).
  2032 
  2033 
  2034 *** ZF ***
  2035 
  2036 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2037   only the theorems proved on ZF.ML;
  2038 
  2039 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2040   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2041   disjointness reasoning but breaking a few old proofs.
  2042 
  2043 * ZF/Update: new theory of function updates
  2044     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2045   may also be iterated as in f(a:=b,c:=d,...);
  2046 
  2047 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2048 
  2049 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2050   [previously, this check worked only if the rewrite rule was unconditional]
  2051   Now rew can involve either definitions or equalities (either == or =).
  2052 
  2053 * case_tac provided for compatibility with HOL
  2054     (like the old excluded_middle_tac, but with subgoals swapped)
  2055 
  2056 
  2057 *** Internal programming interfaces ***
  2058 
  2059 * Pure: several new basic modules made available for general use, see
  2060 also src/Pure/README;
  2061 
  2062 * improved the theory data mechanism to support encapsulation (data
  2063 kind name replaced by private Object.kind, acting as authorization
  2064 key); new type-safe user interface via functor TheoryDataFun; generic
  2065 print_data function becomes basically useless;
  2066 
  2067 * removed global_names compatibility flag -- all theory declarations
  2068 are qualified by default;
  2069 
  2070 * module Pure/Syntax now offers quote / antiquote translation
  2071 functions (useful for Hoare logic etc. with implicit dependencies);
  2072 see HOL/ex/Antiquote for an example use;
  2073 
  2074 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2075 cterm -> thm;
  2076 
  2077 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2078 subgoal;
  2079 
  2080 * Display.print_goals function moved to Locale.print_goals;
  2081 
  2082 * standard print function for goals supports current_goals_markers
  2083 variable for marking begin of proof, end of proof, start of goal; the
  2084 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2085 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2086 for example;
  2087 
  2088 
  2089 
  2090 New in Isabelle98 (January 1998)
  2091 --------------------------------
  2092 
  2093 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2094 
  2095 * changed lexical syntax of terms / types: dots made part of long
  2096 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2097 
  2098 * simpset (and claset) reference variable replaced by functions
  2099 simpset / simpset_ref;
  2100 
  2101 * no longer supports theory aliases (via merge) and non-trivial
  2102 implicit merge of thms' signatures;
  2103 
  2104 * most internal names of constants changed due to qualified names;
  2105 
  2106 * changed Pure/Sequence interface (see Pure/seq.ML);
  2107 
  2108 
  2109 *** General Changes ***
  2110 
  2111 * hierachically structured name spaces (for consts, types, axms, thms
  2112 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2113 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2114 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2115 long_names for fully qualified output names; NOTE: ML programs
  2116 (special tactics, packages etc.) referring to internal names may have
  2117 to be adapted to cope with fully qualified names; in case of severe
  2118 backward campatibility problems try setting 'global_names' at compile
  2119 time to have enrything declared within a flat name space; one may also
  2120 fine tune name declarations in theories via the 'global' and 'local'
  2121 section;
  2122 
  2123 * reimplemented the implicit simpset and claset using the new anytype
  2124 data filed in signatures; references simpset:simpset ref etc. are
  2125 replaced by functions simpset:unit->simpset and
  2126 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2127 to patch your ML files accordingly;
  2128 
  2129 * HTML output now includes theory graph data for display with Java
  2130 applet or isatool browser; data generated automatically via isatool
  2131 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2132 
  2133 * defs may now be conditional; improved rewrite_goals_tac to handle
  2134 conditional equations;
  2135 
  2136 * defs now admits additional type arguments, using TYPE('a) syntax;
  2137 
  2138 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2139 creates a new theory node; implicit merge of thms' signatures is
  2140 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2141 transfer:theory->thm->thm in (rare) cases;
  2142 
  2143 * improved handling of draft signatures / theories; draft thms (and
  2144 ctyps, cterms) are automatically promoted to real ones;
  2145 
  2146 * slightly changed interfaces for oracles: admit many per theory, named
  2147 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2148 
  2149 * print_goals: optional output of const types (set show_consts and
  2150 show_types);
  2151 
  2152 * improved output of warnings (###) and errors (***);
  2153 
  2154 * subgoal_tac displays a warning if the new subgoal has type variables;
  2155 
  2156 * removed old README and Makefiles;
  2157 
  2158 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2159 
  2160 * removed obsolete init_pps and init_database;
  2161 
  2162 * deleted the obsolete tactical STATE, which was declared by
  2163     fun STATE tacfun st = tacfun st st;
  2164 
  2165 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2166 (which abbreviates $HOME);
  2167 
  2168 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2169 use isatool fixseq to adapt your ML programs (this works for fully
  2170 qualified references to the Sequence structure only!);
  2171 
  2172 * use_thy no longer requires writable current directory; it always
  2173 reloads .ML *and* .thy file, if either one is out of date;
  2174 
  2175 
  2176 *** Classical Reasoner ***
  2177 
  2178 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2179 tactics that use classical reasoning to simplify a subgoal without
  2180 splitting it into several subgoals;
  2181 
  2182 * Safe_tac: like safe_tac but uses the default claset;
  2183 
  2184 
  2185 *** Simplifier ***
  2186 
  2187 * added simplification meta rules:
  2188     (asm_)(full_)simplify: simpset -> thm -> thm;
  2189 
  2190 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2191 logics (again);
  2192 
  2193 * added prems argument to simplification procedures;
  2194 
  2195 * HOL, FOL, ZF: added infix function `addsplits':
  2196   instead of `<simpset> setloop (split_tac <thms>)'
  2197   you can simply write `<simpset> addsplits <thms>'
  2198 
  2199 
  2200 *** Syntax ***
  2201 
  2202 * TYPE('a) syntax for type reflection terms;
  2203 
  2204 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2205 
  2206 * pretty printer: changed order of mixfix annotation preference (again!);
  2207 
  2208 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2209 
  2210 
  2211 *** HOL ***
  2212 
  2213 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2214   with `addloop' of the simplifier to faciliate case splitting in premises.
  2215 
  2216 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2217 
  2218 * HOL/Auth: new protocol proofs including some for the Internet
  2219   protocol TLS;
  2220 
  2221 * HOL/Map: new theory of `maps' a la VDM;
  2222 
  2223 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2224 cancelling out common nat summands from =, <, <= (in)equalities, or
  2225 differences; simplification procedures nat_cancel_factor for
  2226 cancelling common factor from =, <, <= (in)equalities over natural
  2227 sums; nat_cancel contains both kinds of procedures, it is installed by
  2228 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2229 
  2230 * HOL/simplifier: terms of the form
  2231   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2232   are rewritten to
  2233   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2234   and those of the form
  2235   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2236   are rewritten to
  2237   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2238 
  2239 * HOL/datatype
  2240   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2241 
  2242   P(t_case f1 ... fn x) =
  2243      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2244         ...
  2245        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2246      )
  2247 
  2248   and a theorem `split_t_case_asm' of the form
  2249 
  2250   P(t_case f1 ... fn x) =
  2251     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2252         ...
  2253        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2254      )
  2255   which can be added to a simpset via `addsplits'. The existing theorems
  2256   expand_list_case and expand_option_case have been renamed to
  2257   split_list_case and split_option_case.
  2258 
  2259 * HOL/Arithmetic:
  2260   - `pred n' is automatically converted to `n-1'.
  2261     Users are strongly encouraged not to use `pred' any longer,
  2262     because it will disappear altogether at some point.
  2263   - Users are strongly encouraged to write "0 < n" rather than
  2264     "n ~= 0". Theorems and proof tools have been modified towards this
  2265     `standard'.
  2266 
  2267 * HOL/Lists:
  2268   the function "set_of_list" has been renamed "set" (and its theorems too);
  2269   the function "nth" now takes its arguments in the reverse order and
  2270   has acquired the infix notation "!" as in "xs!n".
  2271 
  2272 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2273 
  2274 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2275   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2276 
  2277 * HOL/record: extensible records with schematic structural subtyping
  2278 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2279 still lacks various theorems and concrete record syntax;
  2280 
  2281 
  2282 *** HOLCF ***
  2283 
  2284 * removed "axioms" and "generated by" sections;
  2285 
  2286 * replaced "ops" section by extended "consts" section, which is capable of
  2287   handling the continuous function space "->" directly;
  2288 
  2289 * domain package:
  2290   . proves theorems immediately and stores them in the theory,
  2291   . creates hierachical name space,
  2292   . now uses normal mixfix annotations (instead of cinfix...),
  2293   . minor changes to some names and values (for consistency),
  2294   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2295   . separator between mutual domain defs: changed "," to "and",
  2296   . improved handling of sort constraints;  now they have to
  2297     appear on the left-hand side of the equations only;
  2298 
  2299 * fixed LAM <x,y,zs>.b syntax;
  2300 
  2301 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2302 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2303 
  2304 
  2305 *** FOL and ZF ***
  2306 
  2307 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2308   with `addloop' of the simplifier to faciliate case splitting in premises.
  2309 
  2310 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2311 in HOL, they strip ALL and --> from proved theorems;
  2312 
  2313 
  2314 
  2315 New in Isabelle94-8 (May 1997)
  2316 ------------------------------
  2317 
  2318 *** General Changes ***
  2319 
  2320 * new utilities to build / run / maintain Isabelle etc. (in parts
  2321 still somewhat experimental); old Makefiles etc. still functional;
  2322 
  2323 * new 'Isabelle System Manual';
  2324 
  2325 * INSTALL text, together with ./configure and ./build scripts;
  2326 
  2327 * reimplemented type inference for greater efficiency, better error
  2328 messages and clean internal interface;
  2329 
  2330 * prlim command for dealing with lots of subgoals (an easier way of
  2331 setting goals_limit);
  2332 
  2333 
  2334 *** Syntax ***
  2335 
  2336 * supports alternative (named) syntax tables (parser and pretty
  2337 printer); internal interface is provided by add_modesyntax(_i);
  2338 
  2339 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2340 be used in conjunction with the Isabelle symbol font; uses the
  2341 "symbols" syntax table;
  2342 
  2343 * added token_translation interface (may translate name tokens in
  2344 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2345 the current print_mode); IMPORTANT: user print translation functions
  2346 are responsible for marking newly introduced bounds
  2347 (Syntax.mark_boundT);
  2348 
  2349 * token translations for modes "xterm" and "xterm_color" that display
  2350 names in bold, underline etc. or colors (which requires a color
  2351 version of xterm);
  2352 
  2353 * infixes may now be declared with names independent of their syntax;
  2354 
  2355 * added typed_print_translation (like print_translation, but may
  2356 access type of constant);
  2357 
  2358 
  2359 *** Classical Reasoner ***
  2360 
  2361 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2362 some limitations.  Blast_tac...
  2363   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2364   + ignores elimination rules that don't have the correct format
  2365         (the conclusion MUST be a formula variable)
  2366   + ignores types, which can make HOL proofs fail
  2367   + rules must not require higher-order unification, e.g. apply_type in ZF
  2368     [message "Function Var's argument not a bound variable" relates to this]
  2369   + its proof strategy is more general but can actually be slower
  2370 
  2371 * substitution with equality assumptions no longer permutes other
  2372 assumptions;
  2373 
  2374 * minor changes in semantics of addafter (now called addaltern); renamed
  2375 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2376 (and access functions for it);
  2377 
  2378 * improved combination of classical reasoner and simplifier:
  2379   + functions for handling clasimpsets
  2380   + improvement of addss: now the simplifier is called _after_ the
  2381     safe steps.
  2382   + safe variant of addss called addSss: uses safe simplifications
  2383     _during_ the safe steps. It is more complete as it allows multiple
  2384     instantiations of unknowns (e.g. with slow_tac).
  2385 
  2386 *** Simplifier ***
  2387 
  2388 * added interface for simplification procedures (functions that
  2389 produce *proven* rewrite rules on the fly, depending on current
  2390 redex);
  2391 
  2392 * ordering on terms as parameter (used for ordered rewriting);
  2393 
  2394 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2395 
  2396 * the solver is now split into a safe and an unsafe part.
  2397 This should be invisible for the normal user, except that the
  2398 functions setsolver and addsolver have been renamed to setSolver and
  2399 addSolver; added safe_asm_full_simp_tac;
  2400 
  2401 
  2402 *** HOL ***
  2403 
  2404 * a generic induction tactic `induct_tac' which works for all datatypes and
  2405 also for type `nat';
  2406 
  2407 * a generic case distinction tactic `exhaust_tac' which works for all
  2408 datatypes and also for type `nat';
  2409 
  2410 * each datatype comes with a function `size';
  2411 
  2412 * patterns in case expressions allow tuple patterns as arguments to
  2413 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2414 
  2415 * primrec now also works with type nat;
  2416 
  2417 * recdef: a new declaration form, allows general recursive functions to be
  2418 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2419 
  2420 * the constant for negation has been renamed from "not" to "Not" to
  2421 harmonize with FOL, ZF, LK, etc.;
  2422 
  2423 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2424 infinite lists;
  2425 
  2426 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2427 
  2428 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2429 problems in commutative rings, using axiomatic type classes for + and *;
  2430 
  2431 * more examples in HOL/MiniML and HOL/Auth;
  2432 
  2433 * more default rewrite rules for quantifiers, union/intersection;
  2434 
  2435 * a new constant `arbitrary == @x.False';
  2436 
  2437 * HOLCF/IOA replaces old HOL/IOA;
  2438 
  2439 * HOLCF changes: derived all rules and arities
  2440   + axiomatic type classes instead of classes
  2441   + typedef instead of faking type definitions
  2442   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2443   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2444   + eliminated the types void, one, tr
  2445   + use unit lift and bool lift (with translations) instead of one and tr
  2446   + eliminated blift from Lift3.thy (use Def instead of blift)
  2447   all eliminated rules are derived as theorems --> no visible changes ;
  2448 
  2449 
  2450 *** ZF ***
  2451 
  2452 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2453 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2454 as ZF_cs addSIs [equalityI];
  2455 
  2456 
  2457 
  2458 New in Isabelle94-7 (November 96)
  2459 ---------------------------------
  2460 
  2461 * allowing negative levels (as offsets) in prlev and choplev;
  2462 
  2463 * super-linear speedup for large simplifications;
  2464 
  2465 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2466 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2467 FAIL); can suppress it using the command Delsimps (ex_simps @
  2468 all_simps); De Morgan laws are also now included, by default;
  2469 
  2470 * improved printing of ==>  :  ~:
  2471 
  2472 * new object-logic "Sequents" adds linear logic, while replacing LK
  2473 and Modal (thanks to Sara Kalvala);
  2474 
  2475 * HOL/Auth: correctness proofs for authentication protocols;
  2476 
  2477 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2478 examples on HOL/Auth);
  2479 
  2480 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2481 the rewriter and classical reasoner simultaneously;
  2482 
  2483 * function uresult no longer returns theorems in "standard" format;
  2484 regain previous version by: val uresult = standard o uresult;
  2485 
  2486 
  2487 
  2488 New in Isabelle94-6
  2489 -------------------
  2490 
  2491 * oracles -- these establish an interface between Isabelle and trusted
  2492 external reasoners, which may deliver results as theorems;
  2493 
  2494 * proof objects (in particular record all uses of oracles);
  2495 
  2496 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2497 
  2498 * "constdefs" section in theory files;
  2499 
  2500 * "primrec" section (HOL) no longer requires names;
  2501 
  2502 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2503 
  2504 
  2505 
  2506 New in Isabelle94-5
  2507 -------------------
  2508 
  2509 * reduced space requirements;
  2510 
  2511 * automatic HTML generation from theories;
  2512 
  2513 * theory files no longer require "..." (quotes) around most types;
  2514 
  2515 * new examples, including two proofs of the Church-Rosser theorem;
  2516 
  2517 * non-curried (1994) version of HOL is no longer distributed;
  2518 
  2519 
  2520 
  2521 New in Isabelle94-4
  2522 -------------------
  2523 
  2524 * greatly reduced space requirements;
  2525 
  2526 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2527 
  2528 * searchable theorem database (see the section "Retrieving theorems" on
  2529 page 8 of the Reference Manual);
  2530 
  2531 * new examples, including Grabczewski's monumental case study of the
  2532 Axiom of Choice;
  2533 
  2534 * The previous version of HOL renamed to Old_HOL;
  2535 
  2536 * The new version of HOL (previously called CHOL) uses a curried syntax
  2537 for functions.  Application looks like f a b instead of f(a,b);
  2538 
  2539 * Mutually recursive inductive definitions finally work in HOL;
  2540 
  2541 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2542 translates to the operator "split";
  2543 
  2544 
  2545 
  2546 New in Isabelle94-3
  2547 -------------------
  2548 
  2549 * new infix operator, addss, allowing the classical reasoner to
  2550 perform simplification at each step of its search.  Example:
  2551         fast_tac (cs addss ss)
  2552 
  2553 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2554 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2555 look like (a,b) instead of <a,b>;
  2556 
  2557 * PLEASE NOTE: CHOL will eventually replace HOL!
  2558 
  2559 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2560 It translates to the operator "split".  A new theory of integers is available;
  2561 
  2562 * In ZF, integer numerals now denote two's-complement binary integers.
  2563 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2564 
  2565 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2566 of the Axiom of Choice;
  2567 
  2568 
  2569 
  2570 New in Isabelle94-2
  2571 -------------------
  2572 
  2573 * Significantly faster resolution;
  2574 
  2575 * the different sections in a .thy file can now be mixed and repeated
  2576 freely;
  2577 
  2578 * Database of theorems for FOL, HOL and ZF.  New
  2579 commands including qed, qed_goal and bind_thm store theorems in the database.
  2580 
  2581 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2582 a given theory (thms_of), or find out what theory a theorem was proved in
  2583 (theory_of_thm);
  2584 
  2585 * Bugs fixed in the inductive definition and datatype packages;
  2586 
  2587 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2588 and HOL_dup_cs obsolete;
  2589 
  2590 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2591 have been removed;
  2592 
  2593 * Simpler definition of function space in ZF;
  2594 
  2595 * new results about cardinal and ordinal arithmetic in ZF;
  2596 
  2597 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2598 types;
  2599 
  2600 
  2601 $Id$