NEWS
author kleing
Sat Apr 17 00:46:22 2004 +0200 (2004-04-17)
changeset 14610 9c2e31e483b2
parent 14606 0be6c11e7128
child 14624 9b3397a848c3
permissions -rw-r--r--
added HOL-Matrix, added HOL/Matrix/ROOT.ML
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in Isabelle2004 (April 2004)
     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>), calligraphic (\<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   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
    33   superscript. The 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   may consist of any printable characters excluding the end bracket >.
    38 
    39 * Pure: Using new Isar command "finalconsts" (or the ML functions
    40   Theory.add_finals or Theory.add_finals_i) it is now possible to
    41   declare constants "final", which prevents their being given a definition
    42   later.  It is useful for constants whose behaviour is fixed axiomatically
    43   rather than definitionally, such as the meta-logic connectives.
    44 
    45 * Pure: 'instance' now handles general arities with general sorts
    46   (i.e. intersections of classes),
    47 
    48 * Presentation: generated HTML now uses a CSS style sheet to make layout
    49   (somewhat) independent of content. It is copied from lib/html/isabelle.css. 
    50   It can be changed to alter the colors/layout of generated pages.
    51 
    52 
    53 *** Isar ***
    54 
    55 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
    56   cut_tac, subgoal_tac and thin_tac:
    57   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    58     locales are no longer forced to write Isar proof scripts.
    59     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    60     emulations.
    61   - INCOMPATIBILITY: names of variables to be instantiated may no
    62     longer be enclosed in quotes.  Instead, precede variable name with `?'.
    63     This is consistent with the instantiation attribute "where".
    64 
    65 * Attributes "where" and "of":
    66   - Now take type variables of instantiated theorem into account when reading
    67     the instantiation string.  This fixes a bug that caused instantiated
    68     theorems to have too special types in some circumstances.
    69   - "where" permits explicit instantiations of type variables.
    70 
    71 * Calculation commands "moreover" and "also" no longer interfere with
    72   current facts ("this"), admitting arbitrary combinations with "then"
    73   and derived forms.
    74 
    75 * Locales:
    76   - Goal statements involving the context element "includes" no longer
    77     generate theorems with internal delta predicates (those ending on
    78     "_axioms") in the premise.
    79     Resolve particular premise with <locale>.intro to obtain old form.
    80   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
    81     specification and "includes" elements in goal statement.
    82   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
    83     [intro?] and [elim?] (respectively) by default.
    84   - Experimental command for instantiation of locales in proof contexts:
    85         instantiate <label>[<attrs>]: <loc>
    86     Instantiates locale <loc> and adds all its theorems to the current context
    87     taking into account their attributes.  Label and attrs are optional
    88     modifiers, like in theorem declarations.  If present, names of
    89     instantiated theorems are qualified with <label>, and the attributes
    90     <attrs> are applied after any attributes these theorems might have already.
    91       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.  The command does not support old-style locales declared
    94     with "locale (open)".
    95       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
    96 
    97 * HOL: Tactic emulation methods induct_tac and case_tac understand static
    98   (Isar) contexts.
    99 
   100 
   101 *** HOL ***
   102 
   103 * Simplifier:
   104   - Much improved handling of linear and partial orders.
   105     Reasoners for linear and partial orders are set up for type classes
   106     "linorder" and "order" respectively, and are added to the default simpset
   107     as solvers.  This means that the simplifier can build transitivity chains
   108     to solve goals from the assumptions.
   109   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   110     of blast or auto after simplification become unnecessary because the goal
   111     is solved by simplification already.
   112 
   113 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws, 
   114     all proved in axiomatic type classes for semirings, rings and fields.
   115 
   116 * Numerics:
   117   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   118     now formalized using the Ring_and_Field theory mentioned above. 
   119   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   120     than before, because now they are set up once in a generic manner.
   121   - INCOMPATIBILITY: many type-specific arithmetic laws have gone. 
   122     Look for the general versions in Ring_and_Field (and Power if they concern
   123     exponentiation).
   124 
   125 * Type "rat" of the rational numbers is now available in HOL-Complex.
   126 
   127 * Records:
   128   - Record types are now by default printed with their type abbreviation
   129     instead of the list of all field types. This can be configured via
   130     the reference "print_record_type_abbr".
   131   - Simproc "record_upd_simproc" for simplification of multiple updates added 
   132     (not enabled by default).
   133   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   134     EX x. x = sel r to True (not enabled by default).
   135   - Tactic "record_split_simp_tac" to split and simplify records added.
   136  
   137 * 'specification' command added, allowing for definition by
   138   specification.  There is also an 'ax_specification' command that
   139   introduces the new constants axiomatically.
   140 
   141 * arith(_tac) is now able to generate counterexamples for reals as well.
   142 
   143 * HOL-Algebra: new locale "ring" for non-commutative rings.
   144 
   145 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   146   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   147 
   148 * HOL-Matrix: a first theory for matrices in HOL with an application of 
   149   matrix theory to linear programming.
   150 
   151 * Unions and Intersections:
   152   The x-symbol output syntax of UN and INT has been changed
   153   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   154   i.e. the index formulae has become a subscript, like in normal math.
   155   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   156   The subscript version is also accepted as input syntax.
   157 
   158 * Unions and Intersections over Intervals:
   159   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is 
   160   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A" 
   161   like in normal math, and corresponding versions for < and for intersection.
   162 
   163 * ML: the legacy theory structures Int and List have been removed. They had
   164   conflicted with ML Basis Library structures having the same names.
   165 
   166 * 'refute' command added to search for (finite) countermodels.  Only works
   167   for a fragment of HOL.  The installation of an external SAT solver is
   168   highly recommended.  See "HOL/Refute.thy" for details.
   169 
   170 * 'quickcheck' command: Allows to find counterexamples by evaluating
   171   formulae under an assignment of free variables to random values.
   172   In contrast to 'refute', it can deal with inductive datatypes,
   173   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   174   for examples.
   175 
   176 
   177 *** HOLCF ***
   178 
   179 * Streams now come with concatenation and are part of the HOLCF image
   180 
   181 
   182 
   183 New in Isabelle2003 (May 2003)
   184 ------------------------------
   185 
   186 *** General ***
   187 
   188 * Provers/simplifier:
   189 
   190   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   191     Assumptions are now subject to complete mutual simplification,
   192     not just from left to right. The simplifier now preserves
   193     the order of assumptions.
   194 
   195     Potential INCOMPATIBILITY:
   196 
   197     -- simp sometimes diverges where the old version did
   198        not, e.g. invoking simp on the goal
   199 
   200         [| P (f x); y = x; f x = f y |] ==> Q
   201 
   202        now gives rise to the infinite reduction sequence
   203 
   204         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   205 
   206        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   207        kind of problem.
   208 
   209     -- Tactics combining classical reasoner and simplification (such as auto)
   210        are also affected by this change, because many of them rely on
   211        simp. They may sometimes diverge as well or yield a different numbers
   212        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   213        in case of problems. Sometimes subsequent calls to the classical
   214        reasoner will fail because a preceeding call to the simplifier too
   215        eagerly simplified the goal, e.g. deleted redundant premises.
   216 
   217   - The simplifier trace now shows the names of the applied rewrite rules
   218 
   219   - You can limit the number of recursive invocations of the simplifier
   220     during conditional rewriting (where the simplifie tries to solve the
   221     conditions before applying the rewrite rule):
   222     ML "simp_depth_limit := n"
   223     where n is an integer. Thus you can force termination where previously
   224     the simplifier would diverge.
   225 
   226   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   227 
   228   - No longer aborts on failed congruence proof.  Instead, the
   229     congruence is ignored.
   230 
   231 * Pure: New generic framework for extracting programs from constructive
   232   proofs. See HOL/Extraction.thy for an example instantiation, as well
   233   as HOL/Extraction for some case studies.
   234 
   235 * Pure: The main goal of the proof state is no longer shown by default, only
   236 the subgoals. This behaviour is controlled by a new flag.
   237    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   238 (ML: Proof.show_main_goal).
   239 
   240 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   241 rules whose conclusion matches subgoal 1:
   242       PG menu: Isabelle/Isar -> Show me -> matching rules
   243 The rules are ordered by how closely they match the subgoal.
   244 In particular, rules that solve a subgoal outright are displayed first
   245 (or rather last, the way they are printed).
   246 (ML: ProofGeneral.print_intros())
   247 
   248 * Pure: New flag trace_unify_fail causes unification to print
   249 diagnostic information (PG: in trace buffer) when it fails. This is
   250 useful for figuring out why single step proofs like rule, erule or
   251 assumption failed.
   252 
   253 * Pure: Locale specifications now produce predicate definitions
   254 according to the body of text (covering assumptions modulo local
   255 definitions); predicate "loc_axioms" covers newly introduced text,
   256 while "loc" is cumulative wrt. all included locale expressions; the
   257 latter view is presented only on export into the global theory
   258 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   259 on the old view without predicates;
   260 
   261 * Pure: predefined locales "var" and "struct" are useful for sharing
   262 parameters (as in CASL, for example); just specify something like
   263 ``var x + var y + struct M'' as import;
   264 
   265 * Pure: improved thms_containing: proper indexing of facts instead of
   266 raw theorems; check validity of results wrt. current name space;
   267 include local facts of proof configuration (also covers active
   268 locales), cover fixed variables in index; may use "_" in term
   269 specification; an optional limit for the number of printed facts may
   270 be given (the default is 40);
   271 
   272 * Pure: disallow duplicate fact bindings within new-style theory files
   273 (batch-mode only);
   274 
   275 * Provers: improved induct method: assumptions introduced by case
   276 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   277 the goal statement); "foo" still refers to all facts collectively;
   278 
   279 * Provers: the function blast.overloaded has been removed: all constants
   280 are regarded as potentially overloaded, which improves robustness in exchange
   281 for slight decrease in efficiency;
   282 
   283 * Provers/linorder: New generic prover for transitivity reasoning over
   284 linear orders.  Note: this prover is not efficient!
   285 
   286 * Isar: preview of problems to finish 'show' now produce an error
   287 rather than just a warning (in interactive mode);
   288 
   289 
   290 *** HOL ***
   291 
   292 * arith(_tac)
   293 
   294  - Produces a counter example if it cannot prove a goal.
   295    Note that the counter example may be spurious if the goal is not a formula
   296    of quantifier-free linear arithmetic.
   297    In ProofGeneral the counter example appears in the trace buffer.
   298 
   299  - Knows about div k and mod k where k is a numeral of type nat or int.
   300 
   301  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   302    linear arithmetic fails. This takes account of quantifiers and divisibility.
   303    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   304 
   305 * simp's arithmetic capabilities have been enhanced a bit: it now
   306 takes ~= in premises into account (by performing a case split);
   307 
   308 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   309 are distributed over a sum of terms;
   310 
   311 * New tactic "trans_tac" and method "trans" instantiate
   312 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   313 "<=", "<" and "="). 
   314 
   315 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   316 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   317 
   318 * 'typedef' command has new option "open" to suppress the set
   319 definition;
   320 
   321 * functions Min and Max on finite sets have been introduced (theory
   322 Finite_Set);
   323 
   324 * attribute [symmetric] now works for relations as well; it turns
   325 (x,y) : R^-1 into (y,x) : R, and vice versa;
   326 
   327 * induct over a !!-quantified statement (say !!x1..xn):
   328   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   329 
   330 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   331 %x. None. Warning: empty_def now refers to the previously hidden definition
   332 of the empty set.
   333 
   334 * Algebra: formalization of classical algebra.  Intended as base for
   335 any algebraic development in Isabelle.  Currently covers group theory
   336 (up to Sylow's theorem) and ring theory (Universal Property of
   337 Univariate Polynomials).  Contributions welcome;
   338 
   339 * GroupTheory: deleted, since its material has been moved to Algebra;
   340 
   341 * Complex: new directory of the complex numbers with numeric constants, 
   342 nonstandard complex numbers, and some complex analysis, standard and 
   343 nonstandard (Jacques Fleuriot);
   344 
   345 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   346 
   347 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   348 Fleuriot);
   349 
   350 * Real/HahnBanach: updated and adapted to locales;
   351 
   352 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   353 Gray and Kramer);
   354 
   355 * UNITY: added the Meier-Sanders theory of progress sets;
   356 
   357 * MicroJava: bytecode verifier and lightweight bytecode verifier
   358 as abstract algorithms, instantiated to the JVM;
   359 
   360 * Bali: Java source language formalization. Type system, operational
   361 semantics, axiomatic semantics. Supported language features:
   362 classes, interfaces, objects,virtual methods, static methods,
   363 static/instance fields, arrays, access modifiers, definite
   364 assignment, exceptions.
   365 
   366 
   367 *** ZF ***
   368 
   369 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   370 universe, etc.);
   371 
   372 * Main ZF: virtually all theories converted to new-style format;
   373 
   374 
   375 *** ML ***
   376 
   377 * Pure: Tactic.prove provides sane interface for internal proofs;
   378 omits the infamous "standard" operation, so this is more appropriate
   379 than prove_goalw_cterm in many situations (e.g. in simprocs);
   380 
   381 * Pure: improved error reporting of simprocs;
   382 
   383 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   384 up simprocs;
   385 
   386 
   387 *** Document preparation ***
   388 
   389 * uses \par instead of \\ for line breaks in theory text. This may
   390 shift some page breaks in large documents. To get the old behaviour
   391 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   392 
   393 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   394 other packages
   395 
   396 * \<euro> now needs package babel/greek instead of marvosym (which
   397 broke \Rightarrow)
   398 
   399 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   400 textcomp package)
   401 
   402 
   403 
   404 New in Isabelle2002 (March 2002)
   405 --------------------------------
   406 
   407 *** Document preparation ***
   408 
   409 * greatly simplified document preparation setup, including more
   410 graceful interpretation of isatool usedir -i/-d/-D options, and more
   411 instructive isatool mkdir; users should basically be able to get
   412 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   413 users may run a separate document processing stage manually like this:
   414 "isatool usedir -D output HOL Test && isatool document Test/output";
   415 
   416 * theory dependency graph may now be incorporated into documents;
   417 isatool usedir -g true will produce session_graph.eps/.pdf for use
   418 with \includegraphics of LaTeX;
   419 
   420 * proper spacing of consecutive markup elements, especially text
   421 blocks after section headings;
   422 
   423 * support bold style (for single symbols only), input syntax is like
   424 this: "\<^bold>\<alpha>" or "\<^bold>A";
   425 
   426 * \<bullet> is now output as bold \cdot by default, which looks much
   427 better in printed text;
   428 
   429 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   430 note that these symbols are currently unavailable in Proof General /
   431 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   432 
   433 * isatool latex no longer depends on changed TEXINPUTS, instead
   434 isatool document copies the Isabelle style files to the target
   435 location;
   436 
   437 
   438 *** Isar ***
   439 
   440 * Pure/Provers: improved proof by cases and induction;
   441   - 'case' command admits impromptu naming of parameters (such as
   442     "case (Suc n)");
   443   - 'induct' method divinates rule instantiation from the inductive
   444     claim; no longer requires excessive ?P bindings for proper
   445     instantiation of cases;
   446   - 'induct' method properly enumerates all possibilities of set/type
   447     rules; as a consequence facts may be also passed through *type*
   448     rules without further ado;
   449   - 'induct' method now derives symbolic cases from the *rulified*
   450     rule (before it used to rulify cases stemming from the internal
   451     atomized version); this means that the context of a non-atomic
   452     statement becomes is included in the hypothesis, avoiding the
   453     slightly cumbersome show "PROP ?case" form;
   454   - 'induct' may now use elim-style induction rules without chaining
   455     facts, using ``missing'' premises from the goal state; this allows
   456     rules stemming from inductive sets to be applied in unstructured
   457     scripts, while still benefitting from proper handling of non-atomic
   458     statements; NB: major inductive premises need to be put first, all
   459     the rest of the goal is passed through the induction;
   460   - 'induct' proper support for mutual induction involving non-atomic
   461     rule statements (uses the new concept of simultaneous goals, see
   462     below);
   463   - append all possible rule selections, but only use the first
   464     success (no backtracking);
   465   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   466   - undeclared rule case names default to numbers 1, 2, 3, ...;
   467   - added 'print_induct_rules' (covered by help item in recent Proof
   468     General versions);
   469   - moved induct/cases attributes to Pure, methods to Provers;
   470   - generic method setup instantiated for FOL and HOL;
   471 
   472 * Pure: support multiple simultaneous goal statements, for example
   473 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   474 meta-level mechanism, this acts as if several individual goals had
   475 been stated separately; in particular common proof methods need to be
   476 repeated in order to cover all claims; note that a single elimination
   477 step is *not* sufficient to establish the two conjunctions, so this
   478 fails:
   479 
   480   assume "A & B" then have A and B ..   (*".." fails*)
   481 
   482 better use "obtain" in situations as above; alternative refer to
   483 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   484 
   485 * Pure: proper integration with ``locales''; unlike the original
   486 version by Florian Kammüller, Isar locales package high-level proof
   487 contexts rather than raw logical ones (e.g. we admit to include
   488 attributes everywhere); operations on locales include merge and
   489 rename; support for implicit arguments (``structures''); simultaneous
   490 type-inference over imports and text; see also HOL/ex/Locales.thy for
   491 some examples;
   492 
   493 * Pure: the following commands have been ``localized'', supporting a
   494 target locale specification "(in name)": 'lemma', 'theorem',
   495 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   496 stored both within the locale and at the theory level (exported and
   497 qualified by the locale name);
   498 
   499 * Pure: theory goals may now be specified in ``long'' form, with
   500 ad-hoc contexts consisting of arbitrary locale elements. for example
   501 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   502 definitions may be given, too); the result is a meta-level rule with
   503 the context elements being discharged in the obvious way;
   504 
   505 * Pure: new proof command 'using' allows to augment currently used
   506 facts after a goal statement ('using' is syntactically analogous to
   507 'apply', but acts on the goal's facts only); this allows chained facts
   508 to be separated into parts given before and after a claim, as in
   509 ``from a and b have C using d and e <proof>'';
   510 
   511 * Pure: renamed "antecedent" case to "rule_context";
   512 
   513 * Pure: new 'judgment' command records explicit information about the
   514 object-logic embedding (used by several tools internally); no longer
   515 use hard-wired "Trueprop";
   516 
   517 * Pure: added 'corollary' command;
   518 
   519 * Pure: fixed 'token_translation' command;
   520 
   521 * Pure: removed obsolete 'exported' attribute;
   522 
   523 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   524 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   525 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   526 
   527 * Pure: method 'atomize' presents local goal premises as object-level
   528 statements (atomic meta-level propositions); setup controlled via
   529 rewrite rules declarations of 'atomize' attribute; example
   530 application: 'induct' method with proper rule statements in improper
   531 proof *scripts*;
   532 
   533 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   534 now consider the syntactic context of assumptions, giving a better
   535 chance to get type-inference of the arguments right (this is
   536 especially important for locales);
   537 
   538 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   539 mode;
   540 
   541 * Pure/obtain: the formal conclusion "thesis", being marked as
   542 ``internal'', may no longer be reference directly in the text;
   543 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   544 situations;
   545 
   546 * Pure: generic 'sym' attribute which declares a rule both as pure
   547 'elim?' and for the 'symmetric' operation;
   548 
   549 * Pure: marginal comments ``--'' may now occur just anywhere in the
   550 text; the fixed correlation with particular command syntax has been
   551 discontinued;
   552 
   553 * Pure: new method 'rules' is particularly well-suited for proof
   554 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   555 but often produces more compact proof terms with less detours;
   556 
   557 * Pure/Provers/classical: simplified integration with pure rule
   558 attributes and methods; the classical "intro?/elim?/dest?"
   559 declarations coincide with the pure ones; the "rule" method no longer
   560 includes classically swapped intros; "intro" and "elim" methods no
   561 longer pick rules from the context; also got rid of ML declarations
   562 AddXIs/AddXEs/AddXDs; all of this has some potential for
   563 INCOMPATIBILITY;
   564 
   565 * Provers/classical: attribute 'swapped' produces classical inversions
   566 of introduction rules;
   567 
   568 * Provers/simplifier: 'simplified' attribute may refer to explicit
   569 rules instead of full simplifier context; 'iff' attribute handles
   570 conditional rules;
   571 
   572 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   573 
   574 * HOL: 'recdef' now fails on unfinished automated proofs, use
   575 "(permissive)" option to recover old behavior;
   576 
   577 * HOL: 'inductive' no longer features separate (collective) attributes
   578 for 'intros' (was found too confusing);
   579 
   580 * HOL: properly declared induction rules less_induct and
   581 wf_induct_rule;
   582 
   583 
   584 *** HOL ***
   585 
   586 * HOL: moved over to sane numeral syntax; the new policy is as
   587 follows:
   588 
   589   - 0 and 1 are polymorphic constants, which are defined on any
   590   numeric type (nat, int, real etc.);
   591 
   592   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   593   binary representation internally;
   594 
   595   - type nat has special constructor Suc, and generally prefers Suc 0
   596   over 1::nat and Suc (Suc 0) over 2::nat;
   597 
   598 This change may cause significant problems of INCOMPATIBILITY; here
   599 are some hints on converting existing sources:
   600 
   601   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   602   entities, so expressions involving "-" (unary or binary minus) need
   603   to be spaced properly;
   604 
   605   - existing occurrences of "1" may need to be constraint "1::nat" or
   606   even replaced by Suc 0; similar for old "2";
   607 
   608   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   609 
   610   - remove all special provisions on numerals in proofs;
   611 
   612 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   613 representation (depends on bin_arith_simps in the default context);
   614 
   615 * HOL: symbolic syntax for x^2 (numeral 2);
   616 
   617 * HOL: the class of all HOL types is now called "type" rather than
   618 "term"; INCOMPATIBILITY, need to adapt references to this type class
   619 in axclass/classes, instance/arities, and (usually rare) occurrences
   620 in typings (of consts etc.); internally the class is called
   621 "HOL.type", ML programs should refer to HOLogic.typeS;
   622 
   623 * HOL/record package improvements:
   624   - new derived operations "fields" to build a partial record section,
   625     "extend" to promote a fixed record to a record scheme, and
   626     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   627     declared as simp by default;
   628   - shared operations ("more", "fields", etc.) now need to be always
   629     qualified) --- potential INCOMPATIBILITY;
   630   - removed "make_scheme" operations (use "make" with "extend") --
   631     INCOMPATIBILITY;
   632   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   633   - provides cases/induct rules for use with corresponding Isar
   634     methods (for concrete records, record schemes, concrete more
   635     parts, and schematic more parts -- in that order);
   636   - internal definitions directly based on a light-weight abstract
   637     theory of product types over typedef rather than datatype;
   638 
   639 * HOL: generic code generator for generating executable ML code from
   640 specifications; specific support for HOL constructs such as inductive
   641 datatypes and sets, as well as recursive functions; can be invoked
   642 via 'generate_code' theory section;
   643 
   644 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   645 
   646 * HOL: consolidated and renamed several theories.  In particular:
   647 	Ord.thy has been absorbed into HOL.thy
   648 	String.thy has been absorbed into List.thy
   649  
   650 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   651 (beware of argument permutation!);
   652 
   653 * HOL: linorder_less_split superseded by linorder_cases;
   654 
   655 * HOL/List: "nodups" renamed to "distinct";
   656 
   657 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   658 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   659   - Ex_def has changed, now need to use some_eq_ex
   660 
   661 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   662 in this (rare) case use:
   663 
   664   delSWrapper "split_all_tac"
   665   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   666 
   667 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   668 MAY FAIL;
   669 
   670 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   671 Isabelle's type classes, ^ on functions and relations has too general
   672 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   673 necessary to attach explicit type constraints;
   674 
   675 * HOL/Relation: the prefix name of the infix "O" has been changed from
   676 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   677 renamed accordingly (eg "compI" -> "rel_compI").
   678 
   679 * HOL: syntax translations now work properly with numerals and records
   680 expressions;
   681 
   682 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   683 of "lam" -- INCOMPATIBILITY;
   684 
   685 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   686 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   687 renamed "Product_Type.unit";
   688 
   689 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   690 
   691 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   692 the "cases" method);
   693 
   694 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   695 Florian Kammüller);
   696 
   697 * HOL/IMP: updated and converted to new-style theory format; several
   698 parts turned into readable document, with proper Isar proof texts and
   699 some explanations (by Gerwin Klein);
   700 
   701 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   702 
   703 * HOL-Hyperreal is now a logic image;
   704 
   705 
   706 *** HOLCF ***
   707 
   708 * Isar: consts/constdefs supports mixfix syntax for continuous
   709 operations;
   710 
   711 * Isar: domain package adapted to new-style theory format, e.g. see
   712 HOLCF/ex/Dnat.thy;
   713 
   714 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   715 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   716 lift.induct_tac, always use UU instead of Undef;
   717 
   718 * HOLCF/IMP: updated and converted to new-style theory;
   719 
   720 
   721 *** ZF ***
   722 
   723 * Isar: proper integration of logic-specific tools and packages,
   724 including theory commands '(co)inductive', '(co)datatype',
   725 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   726 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   727 
   728 * theory Main no longer includes AC; for the Axiom of Choice, base
   729 your theory on Main_ZFC;
   730 
   731 * the integer library now covers quotients and remainders, with many
   732 laws relating division to addition, multiplication, etc.;
   733 
   734 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   735 typeless version of the formalism;
   736 
   737 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   738 format;
   739 
   740 * ZF/Induct: new directory for examples of inductive definitions,
   741 including theory Multiset for multiset orderings; converted to
   742 new-style theory format;
   743 
   744 * ZF: many new theorems about lists, ordinals, etc.;
   745 
   746 
   747 *** General ***
   748 
   749 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   750 variable proof controls level of detail: 0 = no proofs (only oracle
   751 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   752 also ref manual for further ML interfaces;
   753 
   754 * Pure/axclass: removed obsolete ML interface
   755 goal_subclass/goal_arity;
   756 
   757 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   758 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   759 separate tokens, so expressions involving minus need to be spaced
   760 properly;
   761 
   762 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   763 rather than "infixl" or "infixr";
   764 
   765 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   766 sort constraint specifications in type inference; e.g. "x::_::foo"
   767 ensures that the type of "x" is of sort "foo" (but not necessarily a
   768 type variable);
   769 
   770 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   771 control output of nested => (types); the default behavior is
   772 "type_brackets";
   773 
   774 * Pure/syntax: builtin parse translation for "_constify" turns valued
   775 tokens into AST constants;
   776 
   777 * Pure/syntax: prefer later declarations of translations and print
   778 translation functions; potential INCOMPATIBILITY: need to reverse
   779 multiple declarations for same syntax element constant;
   780 
   781 * Pure/show_hyps reset by default (in accordance to existing Isar
   782 practice);
   783 
   784 * Provers/classical: renamed addaltern to addafter, addSaltern to
   785 addSafter;
   786 
   787 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   788 as well;
   789 
   790 * system: tested support for MacOS X; should be able to get Isabelle +
   791 Proof General to work in a plain Terminal after installing Poly/ML
   792 (e.g. from the Isabelle distribution area) and GNU bash alone
   793 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   794 support requires further installations, e.g. from
   795 http://fink.sourceforge.net/);
   796 
   797 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   798 
   799 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   800 of 40 MB), cf. ML_OPTIONS;
   801 
   802 * system: Proof General keywords specification is now part of the
   803 Isabelle distribution (see etc/isar-keywords.el);
   804 
   805 * system: support for persistent Proof General sessions (refrain from
   806 outdating all loaded theories on startup); user may create writable
   807 logic images like this: ``isabelle -q HOL Test'';
   808 
   809 * system: smart selection of Isabelle process versus Isabelle
   810 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   811 run both "isabelle" and "Isabelle" even if file names are badly
   812 damaged (executable inspects the case of the first letter of its own
   813 name); added separate "isabelle-process" and "isabelle-interface";
   814 
   815 * system: refrain from any attempt at filtering input streams; no
   816 longer support ``8bit'' encoding of old isabelle font, instead proper
   817 iso-latin characters may now be used; the related isatools
   818 "symbolinput" and "nonascii" have disappeared as well;
   819 
   820 * system: removed old "xterm" interface (the print modes "xterm" and
   821 "xterm_color" are still available for direct use in a suitable
   822 terminal);
   823 
   824 
   825 
   826 New in Isabelle99-2 (February 2001)
   827 -----------------------------------
   828 
   829 *** Overview of INCOMPATIBILITIES ***
   830 
   831 * HOL: please note that theories in the Library and elsewhere often use the
   832 new-style (Isar) format; to refer to their theorems in an ML script you must
   833 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   834 
   835 * HOL: inductive package no longer splits induction rule aggressively,
   836 but only as far as specified by the introductions given; the old
   837 format may be recovered via ML function complete_split_rule or attribute
   838 'split_rule (complete)';
   839 
   840 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   841 gfp_Tarski to gfp_unfold;
   842 
   843 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   844 
   845 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   846 relation); infix "^^" has been renamed "``"; infix "``" has been
   847 renamed "`"; "univalent" has been renamed "single_valued";
   848 
   849 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   850 operation;
   851 
   852 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   853 
   854 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   855 
   856 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   857 consequence, it is no longer monotonic wrt. the local goal context
   858 (which is now passed through the inductive cases);
   859 
   860 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   861 \<gg> to \<ggreater>;
   862 
   863 
   864 *** Document preparation ***
   865 
   866 * \isabellestyle{NAME} selects version of Isabelle output (currently
   867 available: are "it" for near math-mode best-style output, "sl" for
   868 slanted text style, and "tt" for plain type-writer; if no
   869 \isabellestyle command is given, output is according to slanted
   870 type-writer);
   871 
   872 * support sub/super scripts (for single symbols only), input syntax is
   873 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   874 
   875 * some more standard symbols; see Appendix A of the system manual for
   876 the complete list of symbols defined in isabellesym.sty;
   877 
   878 * improved isabelle style files; more abstract symbol implementation
   879 (should now use \isamath{...} and \isatext{...} in custom symbol
   880 definitions);
   881 
   882 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   883 state; Note that presentation of goal states does not conform to
   884 actual human-readable proof documents.  Please do not include goal
   885 states into document output unless you really know what you are doing!
   886 
   887 * proper indentation of antiquoted output with proportional LaTeX
   888 fonts;
   889 
   890 * no_document ML operator temporarily disables LaTeX document
   891 generation;
   892 
   893 * isatool unsymbolize tunes sources for plain ASCII communication;
   894 
   895 
   896 *** Isar ***
   897 
   898 * Pure: Isar now suffers initial goal statements to contain unbound
   899 schematic variables (this does not conform to actual readable proof
   900 documents, due to unpredictable outcome and non-compositional proof
   901 checking); users who know what they are doing may use schematic goals
   902 for Prolog-style synthesis of proven results;
   903 
   904 * Pure: assumption method (an implicit finishing) now handles actual
   905 rules as well;
   906 
   907 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   908 initial goal, declare "that" only as Pure intro (only for single
   909 steps); the "that" rule assumption may now be involved in implicit
   910 finishing, thus ".." becomes a feasible for trivial obtains;
   911 
   912 * Pure: default proof step now includes 'intro_classes'; thus trivial
   913 instance proofs may be performed by "..";
   914 
   915 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   916 statements as well;
   917 
   918 * Pure: more robust selection of calculational rules;
   919 
   920 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   921 rule (as well as the assumption rule);
   922 
   923 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   924 lemmas, using the graph browser tool;
   925 
   926 * Pure: predict failure of "show" in interactive mode;
   927 
   928 * Pure: 'thms_containing' now takes actual terms as arguments;
   929 
   930 * HOL: improved method 'induct' --- now handles non-atomic goals
   931 (potential INCOMPATIBILITY); tuned error handling;
   932 
   933 * HOL: cases and induct rules now provide explicit hints about the
   934 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   935 any remaining facts are inserted into the goal verbatim;
   936 
   937 * HOL: local contexts (aka cases) may now contain term bindings as
   938 well; the 'cases' and 'induct' methods new provide a ?case binding for
   939 the result to be shown in each case;
   940 
   941 * HOL: added 'recdef_tc' command;
   942 
   943 * isatool convert assists in eliminating legacy ML scripts;
   944 
   945 
   946 *** HOL ***
   947 
   948 * HOL/Library: a collection of generic theories to be used together
   949 with main HOL; the theory loader path already includes this directory
   950 by default; the following existing theories have been moved here:
   951 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   952 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   953 
   954 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   955 modelling and verification task performed in Isabelle/HOL +
   956 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   957 
   958 * HOL/Algebra: special summation operator SUM no longer exists, it has
   959 been replaced by setsum; infix 'assoc' now has priority 50 (like
   960 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   961 'domain', this makes the theory consistent with mathematical
   962 literature;
   963 
   964 * HOL basics: added overloaded operations "inverse" and "divide"
   965 (infix "/"), syntax for generic "abs" operation, generic summation
   966 operator \<Sum>;
   967 
   968 * HOL/typedef: simplified package, provide more useful rules (see also
   969 HOL/subset.thy);
   970 
   971 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   972 now expressed as a proper nested rule (old-style tactic scripts may
   973 require atomize_strip_tac to cope with non-atomic premises);
   974 
   975 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   976 to "split_conv" (old name still available for compatibility);
   977 
   978 * HOL: improved concrete syntax for strings (e.g. allows translation
   979 rules with string literals);
   980 
   981 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   982  and Fleuriot's mechanization of analysis, including the transcendental
   983  functions for the reals;
   984 
   985 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   986 
   987 
   988 *** CTT ***
   989 
   990 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   991 "lam" is displayed as TWO lambda-symbols
   992 
   993 * CTT: theory Main now available, containing everything (that is, Bool
   994 and Arith);
   995 
   996 
   997 *** General ***
   998 
   999 * Pure: the Simplifier has been implemented properly as a derived rule
  1000 outside of the actual kernel (at last!); the overall performance
  1001 penalty in practical applications is about 50%, while reliability of
  1002 the Isabelle inference kernel has been greatly improved;
  1003 
  1004 * print modes "brackets" and "no_brackets" control output of nested =>
  1005 (types) and ==> (props); the default behaviour is "brackets";
  1006 
  1007 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1008 as assumptions as well;
  1009 
  1010 * system: support Poly/ML 4.0;
  1011 
  1012 * system: isatool install handles KDE version 1 or 2;
  1013 
  1014 
  1015 
  1016 New in Isabelle99-1 (October 2000)
  1017 ----------------------------------
  1018 
  1019 *** Overview of INCOMPATIBILITIES ***
  1020 
  1021 * HOL: simplification of natural numbers is much changed; to partly
  1022 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1023 issue the following ML commands:
  1024 
  1025   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1026   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1027 
  1028 * HOL: simplification no longer dives into case-expressions; this is
  1029 controlled by "t.weak_case_cong" for each datatype t;
  1030 
  1031 * HOL: nat_less_induct renamed to less_induct;
  1032 
  1033 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1034 fixsome to patch .thy and .ML sources automatically;
  1035 
  1036   select_equality  -> some_equality
  1037   select_eq_Ex     -> some_eq_ex
  1038   selectI2EX       -> someI2_ex
  1039   selectI2         -> someI2
  1040   selectI          -> someI
  1041   select1_equality -> some1_equality
  1042   Eps_sym_eq       -> some_sym_eq_trivial
  1043   Eps_eq           -> some_eq_trivial
  1044 
  1045 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1046 
  1047 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1048 instead);
  1049 
  1050 * HOL: the recursion equations generated by 'recdef' are now called
  1051 f.simps instead of f.rules;
  1052 
  1053 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1054 
  1055 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1056 sometimes be needed;
  1057 
  1058 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1059 
  1060 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1061 
  1062 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1063 product is now "<*>" instead of "Times"; the lexicographic product is
  1064 now "<*lex*>" instead of "**";
  1065 
  1066 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1067 of main HOL, but was unused); better use HOL's datatype package;
  1068 
  1069 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1070 the old syntax may be recovered as follows:
  1071 
  1072   syntax (symbols)
  1073     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1074       (infixl "\\<oplus>" 100)
  1075 
  1076 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1077 
  1078 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1079 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1080 internally;
  1081 
  1082 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1083 changed from A/r to A//r;
  1084 
  1085 * ZF: new treatment of arithmetic (nat & int) may break some old
  1086 proofs;
  1087 
  1088 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1089 rulify -> rule_format, elimify -> elim_format, ...);
  1090 
  1091 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1092 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1093 should have to change intro!! to intro? only); replaced "delrule" by
  1094 "rule del";
  1095 
  1096 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1097 
  1098 * Provers: strengthened force_tac by using new first_best_tac;
  1099 
  1100 * LaTeX document preparation: several changes of isabelle.sty (see
  1101 lib/texinputs);
  1102 
  1103 
  1104 *** Document preparation ***
  1105 
  1106 * formal comments (text blocks etc.) in new-style theories may now
  1107 contain antiquotations of thm/prop/term/typ/text to be presented
  1108 according to latex print mode; concrete syntax is like this:
  1109 @{term[show_types] "f(x) = a + x"};
  1110 
  1111 * isatool mkdir provides easy setup of Isabelle session directories,
  1112 including proper document sources;
  1113 
  1114 * generated LaTeX sources are now deleted after successful run
  1115 (isatool document -c); may retain a copy somewhere else via -D option
  1116 of isatool usedir;
  1117 
  1118 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1119 style files, achieving self-contained LaTeX sources and simplifying
  1120 LaTeX debugging;
  1121 
  1122 * old-style theories now produce (crude) LaTeX output as well;
  1123 
  1124 * browser info session directories are now self-contained (may be put
  1125 on WWW server seperately); improved graphs of nested sessions; removed
  1126 graph for 'all sessions';
  1127 
  1128 * several improvements in isabelle style files; \isabellestyle{it}
  1129 produces fake math mode output; \isamarkupheader is now \section by
  1130 default; see lib/texinputs/isabelle.sty etc.;
  1131 
  1132 
  1133 *** Isar ***
  1134 
  1135 * Isar/Pure: local results and corresponding term bindings are now
  1136 subject to Hindley-Milner polymorphism (similar to ML); this
  1137 accommodates incremental type-inference very nicely;
  1138 
  1139 * Isar/Pure: new derived language element 'obtain' supports
  1140 generalized existence reasoning;
  1141 
  1142 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1143 support accumulation of results, without applying any rules yet;
  1144 useful to collect intermediate results without explicit name
  1145 references, and for use with transitivity rules with more than 2
  1146 premises;
  1147 
  1148 * Isar/Pure: scalable support for case-analysis type proofs: new
  1149 'case' language element refers to local contexts symbolically, as
  1150 produced by certain proof methods; internally, case names are attached
  1151 to theorems as "tags";
  1152 
  1153 * Isar/Pure: theory command 'hide' removes declarations from
  1154 class/type/const name spaces;
  1155 
  1156 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1157 indicate potential overloading;
  1158 
  1159 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1160 
  1161 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1162 "{a,b,c}" instead of {a,b,c};
  1163 
  1164 * Isar/Pure now provides its own version of intro/elim/dest
  1165 attributes; useful for building new logics, but beware of confusion
  1166 with the version in Provers/classical;
  1167 
  1168 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1169 case name 'antecedent';
  1170 
  1171 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1172 to the current context is now done automatically);
  1173 
  1174 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1175 for definining proof methods in ML;
  1176 
  1177 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1178 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1179 most cases, one should have to change intro!! to intro? only);
  1180 replaced "delrule" by "rule del";
  1181 
  1182 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1183 'symmetric' attribute (the latter supercedes [RS sym]);
  1184 
  1185 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1186 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1187 well (including splits);
  1188 
  1189 * Isar/Provers: Simplifier and Classical methods now support all kind
  1190 of modifiers used in the past, including 'cong', 'iff', etc.
  1191 
  1192 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1193 of Simplifier and Classical reasoner);
  1194 
  1195 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1196 now support named cases; major packages (inductive, datatype, primrec,
  1197 recdef) support case names and properly name parameters;
  1198 
  1199 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1200 monotonicity conditions are extracted to be proven at end of
  1201 calculations;
  1202 
  1203 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1204 method anyway;
  1205 
  1206 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1207 split_if split_if_asm; datatype package provides theorems foo.splits =
  1208 foo.split foo.split_asm for each datatype;
  1209 
  1210 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1211 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1212 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1213 use "(cases (simplified))" method in proper proof texts);
  1214 
  1215 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1216 
  1217 * Isar: names of theorems etc. may be natural numbers as well;
  1218 
  1219 * Isar: 'pr' command: optional arguments for goals_limit and
  1220 ProofContext.prems_limit; no longer prints theory contexts, but only
  1221 proof states;
  1222 
  1223 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1224 additional print modes to be specified; e.g. "pr(latex)" will print
  1225 proof state according to the Isabelle LaTeX style;
  1226 
  1227 * Isar: improved support for emulating tactic scripts, including proof
  1228 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1229 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1230 (for HOL datatypes);
  1231 
  1232 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1233 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1234 'proof method scripts' have to be in depth-first order;
  1235 
  1236 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1237 
  1238 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1239 should instead use individual commands for printing items
  1240 (print_commands, print_methods etc.);
  1241 
  1242 * Isar: added 'nothing' --- the empty list of theorems;
  1243 
  1244 
  1245 *** HOL ***
  1246 
  1247 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1248 corresponding virtual machine and a specification of its bytecode
  1249 verifier and a lightweight bytecode verifier, including proofs of
  1250 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1251 Cornelia Pusch (see also the homepage of project Bali at
  1252 http://isabelle.in.tum.de/Bali/);
  1253 
  1254 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1255 Clemens Ballarin;
  1256 
  1257 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1258 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1259 Rasmussen;
  1260 
  1261 * HOL/Lattice: fundamental concepts of lattice theory and order
  1262 structures, including duals, properties of bounds versus algebraic
  1263 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1264 Theorem for complete lattices etc.; may also serve as a demonstration
  1265 for abstract algebraic reasoning using axiomatic type classes, and
  1266 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1267 
  1268 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1269 von Oheimb;
  1270 
  1271 * HOL/IMPP: extension of IMP with local variables and mutually
  1272 recursive procedures, by David von Oheimb;
  1273 
  1274 * HOL/Lambda: converted into new-style theory and document;
  1275 
  1276 * HOL/ex/Multiquote: example of multiple nested quotations and
  1277 anti-quotations -- basically a generalized version of de-Bruijn
  1278 representation; very useful in avoiding lifting of operations;
  1279 
  1280 * HOL/record: added general record equality rule to simpset; fixed
  1281 select-update simplification procedure to handle extended records as
  1282 well; admit "r" as field name;
  1283 
  1284 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1285 other numeric types and also as the identity of groups, rings, etc.;
  1286 
  1287 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1288 Types nat and int belong to this axclass;
  1289 
  1290 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1291    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1292    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1293   two terms #m*u and #n*u are replaced by #(m+n)*u
  1294     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1295   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1296     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1297 
  1298 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1299 powerful prover for predicate logic but knows nothing of clasets; see
  1300 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1301 
  1302 * HOL: new version of "case_tac" subsumes both boolean case split and
  1303 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1304 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1305 
  1306 * HOL: simplification no longer dives into case-expressions: only the
  1307 selector expression is simplified, but not the remaining arms; to
  1308 enable full simplification of case-expressions for datatype t, you may
  1309 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1310 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1311 
  1312 * HOL/recdef: the recursion equations generated by 'recdef' for
  1313 function 'f' are now called f.simps instead of f.rules; if all
  1314 termination conditions are proved automatically, these simplification
  1315 rules are added to the simpset, as in primrec; rules may be named
  1316 individually as well, resulting in a separate list of theorems for
  1317 each equation;
  1318 
  1319 * HOL/While is a new theory that provides a while-combinator. It
  1320 permits the definition of tail-recursive functions without the
  1321 provision of a termination measure. The latter is necessary once the
  1322 invariant proof rule for while is applied.
  1323 
  1324 * HOL: new (overloaded) notation for the set of elements below/above
  1325 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1326 
  1327 * HOL: theorems impI, allI, ballI bound as "strip";
  1328 
  1329 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1330 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1331 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1332 
  1333 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1334 
  1335 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1336 main HOL, but was unused);
  1337 
  1338 * HOL: fewer consts declared as global (e.g. have to refer to
  1339 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1340 
  1341 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1342 in case of overlap with user translations (e.g. judgements over
  1343 tuples); (note that the underlying logical represenation is still
  1344 bogus);
  1345 
  1346 
  1347 *** ZF ***
  1348 
  1349 * ZF: simplification automatically cancels common terms in arithmetic
  1350 expressions over nat and int;
  1351 
  1352 * ZF: new treatment of nat to minimize type-checking: all operators
  1353 coerce their operands to a natural number using the function natify,
  1354 making the algebraic laws unconditional;
  1355 
  1356 * ZF: as above, for int: operators coerce their operands to an integer
  1357 using the function intify;
  1358 
  1359 * ZF: the integer library now contains many of the usual laws for the
  1360 orderings, including $<=, and monotonicity laws for $+ and $*;
  1361 
  1362 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1363 simplification;
  1364 
  1365 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1366 to the simplifier and classical reasoner simultaneously;
  1367 
  1368 
  1369 *** General ***
  1370 
  1371 * Provers: blast_tac now handles actual object-logic rules as
  1372 assumptions; note that auto_tac uses blast_tac internally as well;
  1373 
  1374 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1375 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1376 
  1377 * Provers: delrules now handles destruct rules as well (no longer need
  1378 explicit make_elim);
  1379 
  1380 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1381   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1382 use instead the strong form,
  1383   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1384 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1385 from destruct-rules;
  1386 
  1387 * Provers: Simplifier.easy_setup provides a fast path to basic
  1388 Simplifier setup for new object-logics;
  1389 
  1390 * Pure: AST translation rules no longer require constant head on LHS;
  1391 
  1392 * Pure: improved name spaces: ambiguous output is qualified; support
  1393 for hiding of names;
  1394 
  1395 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1396 XSYMBOL_HOME; no longer need to do manual configuration in most
  1397 situations;
  1398 
  1399 * system: compression of ML heaps images may now be controlled via -c
  1400 option of isabelle and isatool usedir (currently only observed by
  1401 Poly/ML);
  1402 
  1403 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1404 useful for remote X11);
  1405 
  1406 * system: provide TAGS file for Isabelle sources;
  1407 
  1408 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1409 order;
  1410 
  1411 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1412 timing flag supersedes proof_timing and Toplevel.trace;
  1413 
  1414 * ML: new combinators |>> and |>>> for incremental transformations
  1415 with secondary results (e.g. certain theory extensions):
  1416 
  1417 * ML: PureThy.add_defs gets additional argument to indicate potential
  1418 overloading (usually false);
  1419 
  1420 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1421 results;
  1422 
  1423 
  1424 
  1425 New in Isabelle99 (October 1999)
  1426 --------------------------------
  1427 
  1428 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1429 
  1430 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1431 are no longer simplified.  (This allows the simplifier to unfold recursive
  1432 functional programs.)  To restore the old behaviour, declare
  1433 
  1434     Delcongs [if_weak_cong];
  1435 
  1436 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1437 complement;
  1438 
  1439 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1440 
  1441 * HOL/datatype: mutual_induct_tac no longer exists --
  1442   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1443 
  1444 * HOL/typedef: fixed type inference for representing set; type
  1445 arguments now have to occur explicitly on the rhs as type constraints;
  1446 
  1447 * ZF: The con_defs part of an inductive definition may no longer refer
  1448 to constants declared in the same theory;
  1449 
  1450 * HOL, ZF: the function mk_cases, generated by the inductive
  1451 definition package, has lost an argument.  To simplify its result, it
  1452 uses the default simpset instead of a supplied list of theorems.
  1453 
  1454 * HOL/List: the constructors of type list are now Nil and Cons;
  1455 
  1456 * Simplifier: the type of the infix ML functions
  1457         setSSolver addSSolver setSolver addSolver
  1458 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1459 for packaging solvers. A solver is created via
  1460         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1461 where the string argument is only a comment.
  1462 
  1463 
  1464 *** Proof tools ***
  1465 
  1466 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1467 decision procedure for linear arithmetic. Currently it is used for
  1468 types `nat', `int', and `real' in HOL (see below); it can, should and
  1469 will be instantiated for other types and logics as well.
  1470 
  1471 * The simplifier now accepts rewrite rules with flexible heads, eg
  1472      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1473   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1474   matching.
  1475 
  1476 
  1477 *** General ***
  1478 
  1479 * New Isabelle/Isar subsystem provides an alternative to traditional
  1480 tactical theorem proving; together with the ProofGeneral/isar user
  1481 interface it offers an interactive environment for developing human
  1482 readable proof documents (Isar == Intelligible semi-automated
  1483 reasoning); for further information see isatool doc isar-ref,
  1484 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1485 
  1486 * improved and simplified presentation of theories: better HTML markup
  1487 (including colors), graph views in several sizes; isatool usedir now
  1488 provides a proper interface for user theories (via -P option); actual
  1489 document preparation based on (PDF)LaTeX is available as well (for
  1490 new-style theories only); see isatool doc system for more information;
  1491 
  1492 * native support for Proof General, both for classic Isabelle and
  1493 Isabelle/Isar;
  1494 
  1495 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1496 using the graph browser tool;
  1497 
  1498 * Isabelle manuals now also available as PDF;
  1499 
  1500 * theory loader rewritten from scratch (may not be fully
  1501 bug-compatible); old loadpath variable has been replaced by show_path,
  1502 add_path, del_path, reset_path functions; new operations such as
  1503 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1504 isatool doc ref);
  1505 
  1506 * improved isatool install: option -k creates KDE application icon,
  1507 option -p DIR installs standalone binaries;
  1508 
  1509 * added ML_PLATFORM setting (useful for cross-platform installations);
  1510 more robust handling of platform specific ML images for SML/NJ;
  1511 
  1512 * the settings environment is now statically scoped, i.e. it is never
  1513 created again in sub-processes invoked from isabelle, isatool, or
  1514 Isabelle;
  1515 
  1516 * path element specification '~~' refers to '$ISABELLE_HOME';
  1517 
  1518 * in locales, the "assumes" and "defines" parts may be omitted if
  1519 empty;
  1520 
  1521 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1522 long arrows);
  1523 
  1524 * new print_mode "HTML";
  1525 
  1526 * new flag show_tags controls display of tags of theorems (which are
  1527 basically just comments that may be attached by some tools);
  1528 
  1529 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1530 mode and goal output format:
  1531 
  1532 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1533 244c244
  1534 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1535 ---
  1536 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1537 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1538 181c181
  1539 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1540 ---
  1541 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1542 
  1543 * function bind_thms stores lists of theorems (cf. bind_thm);
  1544 
  1545 * new shorthand tactics ftac, eatac, datac, fatac;
  1546 
  1547 * qed (and friends) now accept "" as result name; in that case the
  1548 theorem is not stored, but proper checks and presentation of the
  1549 result still apply;
  1550 
  1551 * theorem database now also indexes constants "Trueprop", "all",
  1552 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1553 
  1554 
  1555 *** HOL ***
  1556 
  1557 ** HOL arithmetic **
  1558 
  1559 * There are now decision procedures for linear arithmetic over nat and
  1560 int:
  1561 
  1562 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1563 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1564 are treated as atomic; subformulae not involving type `nat' or `int'
  1565 are ignored; quantified subformulae are ignored unless they are
  1566 positive universal or negative existential. The tactic has to be
  1567 invoked by hand and can be a little bit slow. In particular, the
  1568 running time is exponential in the number of occurrences of `min' and
  1569 `max', and `-' on `nat'.
  1570 
  1571 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1572 (negated) (in)equalities among the premises and the conclusion into
  1573 account (i.e. no compound formulae) and does not know about `min' and
  1574 `max', and `-' on `nat'. It is fast and is used automatically by the
  1575 simplifier.
  1576 
  1577 NB: At the moment, these decision procedures do not cope with mixed
  1578 nat/int formulae where the two parts interact, such as `m < n ==>
  1579 int(m) < int(n)'.
  1580 
  1581 * HOL/Numeral provides a generic theory of numerals (encoded
  1582 efficiently as bit strings); setup for types nat/int/real is in place;
  1583 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1584 int, existing theories and proof scripts may require a few additional
  1585 type constraints;
  1586 
  1587 * integer division and remainder can now be performed on constant
  1588 arguments;
  1589 
  1590 * many properties of integer multiplication, division and remainder
  1591 are now available;
  1592 
  1593 * An interface to the Stanford Validity Checker (SVC) is available through the
  1594 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1595 are proved automatically.  SVC must be installed separately, and its results
  1596 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1597 invocation of the underlying oracle).  For SVC see
  1598   http://verify.stanford.edu/SVC
  1599 
  1600 * IsaMakefile: the HOL-Real target now builds an actual image;
  1601 
  1602 
  1603 ** HOL misc **
  1604 
  1605 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1606 (in Isabelle/Isar) -- by Gertrud Bauer;
  1607 
  1608 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1609 analysis for assembly languages with subtypes;
  1610 
  1611 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1612 -- avoids syntactic ambiguities and treats state, transition, and
  1613 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1614 changed syntax and (many) tactics;
  1615 
  1616 * HOL/inductive: Now also handles more general introduction rules such
  1617   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1618   theorems are now maintained within the theory (maintained via the
  1619   "mono" attribute);
  1620 
  1621 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1622   (using function types) such as
  1623 
  1624   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1625 
  1626 * HOL/record: record_simproc (part of the default simpset) takes care
  1627 of selectors applied to updated records; record_split_tac is no longer
  1628 part of the default claset; update_defs may now be removed from the
  1629 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1630 
  1631   claset_ref () := claset() addSWrapper record_split_wrapper;
  1632   Delsimprocs [record_simproc]
  1633 
  1634 * HOL/typedef: fixed type inference for representing set; type
  1635 arguments now have to occur explicitly on the rhs as type constraints;
  1636 
  1637 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1638 names rather than an ML expression;
  1639 
  1640 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1641 supplied later.  Program schemes can be defined, such as
  1642     "While B C s = (if B s then While B C (C s) else s)"
  1643 where the well-founded relation can be chosen after B and C have been given.
  1644 
  1645 * HOL/List: the constructors of type list are now Nil and Cons;
  1646 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1647 course, ML tools referring to List.list.op # etc. have to be adapted;
  1648 
  1649 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1650 disabled by default; run isabelle with option -m HOL to get back to
  1651 the original Gordon/HOL-style output;
  1652 
  1653 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1654 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1655 
  1656 * HOL basic syntax simplified (more orthogonal): all variants of
  1657 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1658 Eps operator is provided as well: "SOME x. P[x]";
  1659 
  1660 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1661 
  1662 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1663 thus available for user theories;
  1664 
  1665 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1666 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1667 time;
  1668 
  1669 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1670 several times and then mp;
  1671 
  1672 
  1673 *** LK ***
  1674 
  1675 * the notation <<...>> is now available as a notation for sequences of
  1676 formulas;
  1677 
  1678 * the simplifier is now installed
  1679 
  1680 * the axiom system has been generalized (thanks to Soren Heilmann)
  1681 
  1682 * the classical reasoner now has a default rule database
  1683 
  1684 
  1685 *** ZF ***
  1686 
  1687 * new primrec section allows primitive recursive functions to be given
  1688 directly (as in HOL) over datatypes and the natural numbers;
  1689 
  1690 * new tactics induct_tac and exhaust_tac for induction (or case
  1691 analysis) over datatypes and the natural numbers;
  1692 
  1693 * the datatype declaration of type T now defines the recursor T_rec;
  1694 
  1695 * simplification automatically does freeness reasoning for datatype
  1696 constructors;
  1697 
  1698 * automatic type-inference, with AddTCs command to insert new
  1699 type-checking rules;
  1700 
  1701 * datatype introduction rules are now added as Safe Introduction rules
  1702 to the claset;
  1703 
  1704 * the syntax "if P then x else y" is now available in addition to
  1705 if(P,x,y);
  1706 
  1707 
  1708 *** Internal programming interfaces ***
  1709 
  1710 * tuned simplifier trace output; new flag debug_simp;
  1711 
  1712 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1713 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1714 
  1715 * AxClass.axclass_tac lost the theory argument;
  1716 
  1717 * tuned current_goals_markers semantics: begin / end goal avoids
  1718 printing empty lines;
  1719 
  1720 * removed prs and prs_fn hook, which was broken because it did not
  1721 include \n in its semantics, forcing writeln to add one
  1722 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1723 string -> unit if you really want to output text without newline;
  1724 
  1725 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1726 plain output, interface builders may have to enable 'isabelle_font'
  1727 mode to get Isabelle font glyphs as before;
  1728 
  1729 * refined token_translation interface; INCOMPATIBILITY: output length
  1730 now of type real instead of int;
  1731 
  1732 * theory loader actions may be traced via new ThyInfo.add_hook
  1733 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1734 your own database of information attached to *whole* theories -- as
  1735 opposed to intra-theory data slots offered via TheoryDataFun;
  1736 
  1737 * proper handling of dangling sort hypotheses (at last!);
  1738 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1739 extra sort hypotheses that can be witnessed from the type signature;
  1740 the force_strip_shyps flag is gone, any remaining shyps are simply
  1741 left in the theorem (with a warning issued by strip_shyps_warning);
  1742 
  1743 
  1744 
  1745 New in Isabelle98-1 (October 1998)
  1746 ----------------------------------
  1747 
  1748 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1749 
  1750 * several changes of automated proof tools;
  1751 
  1752 * HOL: major changes to the inductive and datatype packages, including
  1753 some minor incompatibilities of theory syntax;
  1754 
  1755 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1756 called `inj_on';
  1757 
  1758 * HOL: removed duplicate thms in Arith:
  1759   less_imp_add_less  should be replaced by  trans_less_add1
  1760   le_imp_add_le      should be replaced by  trans_le_add1
  1761 
  1762 * HOL: unary minus is now overloaded (new type constraints may be
  1763 required);
  1764 
  1765 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1766 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1767 now taken as an integer constant.
  1768 
  1769 * Pure: ML function 'theory_of' renamed to 'theory';
  1770 
  1771 
  1772 *** Proof tools ***
  1773 
  1774 * Simplifier:
  1775   1. Asm_full_simp_tac is now more aggressive.
  1776      1. It will sometimes reorient premises if that increases their power to
  1777         simplify.
  1778      2. It does no longer proceed strictly from left to right but may also
  1779         rotate premises to achieve further simplification.
  1780      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1781      old Asm_full_simp_tac in that it does not rotate premises.
  1782   2. The simplifier now knows a little bit about nat-arithmetic.
  1783 
  1784 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1785 allows for selected deletion of wrappers, by introduction of names for
  1786 wrapper functionals.  This implies that addbefore, addSbefore,
  1787 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1788 and that adding two tactics with the same name overwrites the first
  1789 one (emitting a warning).
  1790   type wrapper = (int -> tactic) -> (int -> tactic)
  1791   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1792   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1793   delWrapper, delSWrapper: claset *  string            -> claset
  1794   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1795 
  1796 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1797 semantics; addbefore now affects only the unsafe part of step_tac
  1798 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1799 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1800 by Force_tac;
  1801 
  1802 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1803 compWrapper; added safe wrapper (and access functions for it);
  1804 
  1805 * HOL/split_all_tac is now much faster and fails if there is nothing
  1806 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1807 and the names of the automatically generated variables have changed.
  1808 split_all_tac has moved within claset() from unsafe wrappers to safe
  1809 wrappers, which means that !!-bound variables are split much more
  1810 aggressively, and safe_tac and clarify_tac now split such variables.
  1811 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1812 Note: the same holds for record_split_tac, which does the job of
  1813 split_all_tac for record fields.
  1814 
  1815 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1816 permanently to the default simpset using Addsplits just like
  1817 Addsimps. They can be removed via Delsplits just like
  1818 Delsimps. Lower-case versions are also available.
  1819 
  1820 * HOL/Simplifier: The rule split_if is now part of the default
  1821 simpset. This means that the simplifier will eliminate all occurrences
  1822 of if-then-else in the conclusion of a goal. To prevent this, you can
  1823 either remove split_if completely from the default simpset by
  1824 `Delsplits [split_if]' or remove it in a specific call of the
  1825 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1826 other case splitting rules to/from the default simpset: every datatype
  1827 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1828 t is the name of the datatype).
  1829 
  1830 * Classical reasoner / Simplifier combination: new force_tac (and
  1831 derivatives Force_tac, force) combines rewriting and classical
  1832 reasoning (and whatever other tools) similarly to auto_tac, but is
  1833 aimed to solve the given subgoal completely.
  1834 
  1835 
  1836 *** General ***
  1837 
  1838 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1839 and `goalw': the theory is no longer needed as an explicit argument -
  1840 the current theory context is used; assumptions are no longer returned
  1841 at the ML-level unless one of them starts with ==> or !!; it is
  1842 recommended to convert to these new commands using isatool fixgoal
  1843 (backup your sources first!);
  1844 
  1845 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1846 the current theory context, and 'theory' to lookup stored theories;
  1847 
  1848 * new theory section 'locale' for declaring constants, assumptions and
  1849 definitions that have local scope;
  1850 
  1851 * new theory section 'nonterminals' for purely syntactic types;
  1852 
  1853 * new theory section 'setup' for generic ML setup functions
  1854 (e.g. package initialization);
  1855 
  1856 * the distribution now includes Isabelle icons: see
  1857 lib/logo/isabelle-{small,tiny}.xpm;
  1858 
  1859 * isatool install - install binaries with absolute references to
  1860 ISABELLE_HOME/bin;
  1861 
  1862 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1863 
  1864 * print mode 'emacs' reserved for Isamode;
  1865 
  1866 * support multiple print (ast) translations per constant name;
  1867 
  1868 * theorems involving oracles are now printed with a suffixed [!];
  1869 
  1870 
  1871 *** HOL ***
  1872 
  1873 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1874 
  1875 * HOL/inductive package reorganized and improved: now supports mutual
  1876 definitions such as
  1877 
  1878   inductive EVEN ODD
  1879     intrs
  1880       null "0 : EVEN"
  1881       oddI "n : EVEN ==> Suc n : ODD"
  1882       evenI "n : ODD ==> Suc n : EVEN"
  1883 
  1884 new theorem list "elims" contains an elimination rule for each of the
  1885 recursive sets; inductive definitions now handle disjunctive premises
  1886 correctly (also ZF);
  1887 
  1888 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1889 "mutual_induct" no longer exists - the induction rule is always
  1890 contained in "induct";
  1891 
  1892 
  1893 * HOL/datatype package re-implemented and greatly improved: now
  1894 supports mutually recursive datatypes such as
  1895 
  1896   datatype
  1897     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1898             | SUM ('a aexp) ('a aexp)
  1899             | DIFF ('a aexp) ('a aexp)
  1900             | NUM 'a
  1901   and
  1902     'a bexp = LESS ('a aexp) ('a aexp)
  1903             | AND ('a bexp) ('a bexp)
  1904             | OR ('a bexp) ('a bexp)
  1905 
  1906 as well as indirectly recursive datatypes such as
  1907 
  1908   datatype
  1909     ('a, 'b) term = Var 'a
  1910                   | App 'b ((('a, 'b) term) list)
  1911 
  1912 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1913 induction on mutually / indirectly recursive datatypes.
  1914 
  1915 Primrec equations are now stored in theory and can be accessed via
  1916 <function_name>.simps.
  1917 
  1918 INCOMPATIBILITIES:
  1919 
  1920   - Theories using datatypes must now have theory Datatype as an
  1921     ancestor.
  1922   - The specific <typename>.induct_tac no longer exists - use the
  1923     generic induct_tac instead.
  1924   - natE has been renamed to nat.exhaust - use exhaust_tac
  1925     instead of res_inst_tac ... natE. Note that the variable
  1926     names in nat.exhaust differ from the names in natE, this
  1927     may cause some "fragile" proofs to fail.
  1928   - The theorems split_<typename>_case and split_<typename>_case_asm
  1929     have been renamed to <typename>.split and <typename>.split_asm.
  1930   - Since default sorts of type variables are now handled correctly,
  1931     some datatype definitions may have to be annotated with explicit
  1932     sort constraints.
  1933   - Primrec definitions no longer require function name and type
  1934     of recursive argument.
  1935 
  1936 Consider using isatool fixdatatype to adapt your theories and proof
  1937 scripts to the new package (backup your sources first!).
  1938 
  1939 
  1940 * HOL/record package: considerably improved implementation; now
  1941 includes concrete syntax for record types, terms, updates; theorems
  1942 for surjective pairing and splitting !!-bound record variables; proof
  1943 support is as follows:
  1944 
  1945   1) standard conversions (selectors or updates applied to record
  1946 constructor terms) are part of the standard simpset;
  1947 
  1948   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1949 made part of standard simpset and claset via addIffs;
  1950 
  1951   3) a tactic for record field splitting (record_split_tac) is part of
  1952 the standard claset (addSWrapper);
  1953 
  1954 To get a better idea about these rules you may retrieve them via
  1955 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1956 the name of your record type.
  1957 
  1958 The split tactic 3) conceptually simplifies by the following rule:
  1959 
  1960   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1961 
  1962 Thus any record variable that is bound by meta-all will automatically
  1963 blow up into some record constructor term, consequently the
  1964 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1965 solve record problems automatically.
  1966 
  1967 
  1968 * reorganized the main HOL image: HOL/Integ and String loaded by
  1969 default; theory Main includes everything;
  1970 
  1971 * automatic simplification of integer sums and comparisons, using cancellation;
  1972 
  1973 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1974 
  1975 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1976 
  1977 * many new identities for unions, intersections, set difference, etc.;
  1978 
  1979 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1980 called split_if, split_split, split_sum_case and split_nat_case (to go
  1981 with add/delsplits);
  1982 
  1983 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1984 (?x::unit) = (); this is made part of the default simpset, which COULD
  1985 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1986 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1987 unit_abs_eta_conv is added in order to counter the effect of
  1988 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1989 %u.f();
  1990 
  1991 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1992 makes more sense);
  1993 
  1994 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1995   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1996   disjointness reasoning but breaking a few old proofs.
  1997 
  1998 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1999 to 'converse' from 'inverse' (for compatibility with ZF and some
  2000 literature);
  2001 
  2002 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2003 the well-founded relation;
  2004 
  2005 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2006     Compl A.  The "Compl" syntax remains available as input syntax for this
  2007     release ONLY.
  2008 
  2009 * HOL/Update: new theory of function updates:
  2010     f(a:=b) == %x. if x=a then b else f x
  2011 may also be iterated as in f(a:=b,c:=d,...);
  2012 
  2013 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2014 
  2015 * HOL/List:
  2016   - new function list_update written xs[i:=v] that updates the i-th
  2017     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2018   - new function `upt' written [i..j(] which generates the list
  2019     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2020     bound write [i..j], which is a shorthand for [i..j+1(].
  2021   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2022 
  2023 * HOL/Arith:
  2024   - removed 'pred' (predecessor) function;
  2025   - generalized some theorems about n-1;
  2026   - many new laws about "div" and "mod";
  2027   - new laws about greatest common divisors (see theory ex/Primes);
  2028 
  2029 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2030 instead of "inverse";
  2031 
  2032 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2033   of the multiset ordering;
  2034 
  2035 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2036   (not included by default);
  2037 
  2038 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2039 
  2040 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2041   programs, i.e. different program variables may have different types.
  2042 
  2043 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2044   [previously, this check worked only if the rewrite rule was unconditional]
  2045   Now rew can involve either definitions or equalities (either == or =).
  2046 
  2047 
  2048 *** ZF ***
  2049 
  2050 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2051   only the theorems proved on ZF.ML;
  2052 
  2053 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2054   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2055   disjointness reasoning but breaking a few old proofs.
  2056 
  2057 * ZF/Update: new theory of function updates
  2058     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2059   may also be iterated as in f(a:=b,c:=d,...);
  2060 
  2061 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2062 
  2063 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2064   [previously, this check worked only if the rewrite rule was unconditional]
  2065   Now rew can involve either definitions or equalities (either == or =).
  2066 
  2067 * case_tac provided for compatibility with HOL
  2068     (like the old excluded_middle_tac, but with subgoals swapped)
  2069 
  2070 
  2071 *** Internal programming interfaces ***
  2072 
  2073 * Pure: several new basic modules made available for general use, see
  2074 also src/Pure/README;
  2075 
  2076 * improved the theory data mechanism to support encapsulation (data
  2077 kind name replaced by private Object.kind, acting as authorization
  2078 key); new type-safe user interface via functor TheoryDataFun; generic
  2079 print_data function becomes basically useless;
  2080 
  2081 * removed global_names compatibility flag -- all theory declarations
  2082 are qualified by default;
  2083 
  2084 * module Pure/Syntax now offers quote / antiquote translation
  2085 functions (useful for Hoare logic etc. with implicit dependencies);
  2086 see HOL/ex/Antiquote for an example use;
  2087 
  2088 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2089 cterm -> thm;
  2090 
  2091 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2092 subgoal;
  2093 
  2094 * Display.print_goals function moved to Locale.print_goals;
  2095 
  2096 * standard print function for goals supports current_goals_markers
  2097 variable for marking begin of proof, end of proof, start of goal; the
  2098 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2099 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2100 for example;
  2101 
  2102 
  2103 
  2104 New in Isabelle98 (January 1998)
  2105 --------------------------------
  2106 
  2107 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2108 
  2109 * changed lexical syntax of terms / types: dots made part of long
  2110 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2111 
  2112 * simpset (and claset) reference variable replaced by functions
  2113 simpset / simpset_ref;
  2114 
  2115 * no longer supports theory aliases (via merge) and non-trivial
  2116 implicit merge of thms' signatures;
  2117 
  2118 * most internal names of constants changed due to qualified names;
  2119 
  2120 * changed Pure/Sequence interface (see Pure/seq.ML);
  2121 
  2122 
  2123 *** General Changes ***
  2124 
  2125 * hierachically structured name spaces (for consts, types, axms, thms
  2126 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2127 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2128 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2129 long_names for fully qualified output names; NOTE: ML programs
  2130 (special tactics, packages etc.) referring to internal names may have
  2131 to be adapted to cope with fully qualified names; in case of severe
  2132 backward campatibility problems try setting 'global_names' at compile
  2133 time to have enrything declared within a flat name space; one may also
  2134 fine tune name declarations in theories via the 'global' and 'local'
  2135 section;
  2136 
  2137 * reimplemented the implicit simpset and claset using the new anytype
  2138 data filed in signatures; references simpset:simpset ref etc. are
  2139 replaced by functions simpset:unit->simpset and
  2140 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2141 to patch your ML files accordingly;
  2142 
  2143 * HTML output now includes theory graph data for display with Java
  2144 applet or isatool browser; data generated automatically via isatool
  2145 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2146 
  2147 * defs may now be conditional; improved rewrite_goals_tac to handle
  2148 conditional equations;
  2149 
  2150 * defs now admits additional type arguments, using TYPE('a) syntax;
  2151 
  2152 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2153 creates a new theory node; implicit merge of thms' signatures is
  2154 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2155 transfer:theory->thm->thm in (rare) cases;
  2156 
  2157 * improved handling of draft signatures / theories; draft thms (and
  2158 ctyps, cterms) are automatically promoted to real ones;
  2159 
  2160 * slightly changed interfaces for oracles: admit many per theory, named
  2161 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2162 
  2163 * print_goals: optional output of const types (set show_consts and
  2164 show_types);
  2165 
  2166 * improved output of warnings (###) and errors (***);
  2167 
  2168 * subgoal_tac displays a warning if the new subgoal has type variables;
  2169 
  2170 * removed old README and Makefiles;
  2171 
  2172 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2173 
  2174 * removed obsolete init_pps and init_database;
  2175 
  2176 * deleted the obsolete tactical STATE, which was declared by
  2177     fun STATE tacfun st = tacfun st st;
  2178 
  2179 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2180 (which abbreviates $HOME);
  2181 
  2182 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2183 use isatool fixseq to adapt your ML programs (this works for fully
  2184 qualified references to the Sequence structure only!);
  2185 
  2186 * use_thy no longer requires writable current directory; it always
  2187 reloads .ML *and* .thy file, if either one is out of date;
  2188 
  2189 
  2190 *** Classical Reasoner ***
  2191 
  2192 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2193 tactics that use classical reasoning to simplify a subgoal without
  2194 splitting it into several subgoals;
  2195 
  2196 * Safe_tac: like safe_tac but uses the default claset;
  2197 
  2198 
  2199 *** Simplifier ***
  2200 
  2201 * added simplification meta rules:
  2202     (asm_)(full_)simplify: simpset -> thm -> thm;
  2203 
  2204 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2205 logics (again);
  2206 
  2207 * added prems argument to simplification procedures;
  2208 
  2209 * HOL, FOL, ZF: added infix function `addsplits':
  2210   instead of `<simpset> setloop (split_tac <thms>)'
  2211   you can simply write `<simpset> addsplits <thms>'
  2212 
  2213 
  2214 *** Syntax ***
  2215 
  2216 * TYPE('a) syntax for type reflection terms;
  2217 
  2218 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2219 
  2220 * pretty printer: changed order of mixfix annotation preference (again!);
  2221 
  2222 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2223 
  2224 
  2225 *** HOL ***
  2226 
  2227 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2228   with `addloop' of the simplifier to faciliate case splitting in premises.
  2229 
  2230 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2231 
  2232 * HOL/Auth: new protocol proofs including some for the Internet
  2233   protocol TLS;
  2234 
  2235 * HOL/Map: new theory of `maps' a la VDM;
  2236 
  2237 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2238 cancelling out common nat summands from =, <, <= (in)equalities, or
  2239 differences; simplification procedures nat_cancel_factor for
  2240 cancelling common factor from =, <, <= (in)equalities over natural
  2241 sums; nat_cancel contains both kinds of procedures, it is installed by
  2242 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2243 
  2244 * HOL/simplifier: terms of the form
  2245   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2246   are rewritten to
  2247   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2248   and those of the form
  2249   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2250   are rewritten to
  2251   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2252 
  2253 * HOL/datatype
  2254   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2255 
  2256   P(t_case f1 ... fn x) =
  2257      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2258         ...
  2259        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2260      )
  2261 
  2262   and a theorem `split_t_case_asm' of the form
  2263 
  2264   P(t_case f1 ... fn x) =
  2265     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2266         ...
  2267        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2268      )
  2269   which can be added to a simpset via `addsplits'. The existing theorems
  2270   expand_list_case and expand_option_case have been renamed to
  2271   split_list_case and split_option_case.
  2272 
  2273 * HOL/Arithmetic:
  2274   - `pred n' is automatically converted to `n-1'.
  2275     Users are strongly encouraged not to use `pred' any longer,
  2276     because it will disappear altogether at some point.
  2277   - Users are strongly encouraged to write "0 < n" rather than
  2278     "n ~= 0". Theorems and proof tools have been modified towards this
  2279     `standard'.
  2280 
  2281 * HOL/Lists:
  2282   the function "set_of_list" has been renamed "set" (and its theorems too);
  2283   the function "nth" now takes its arguments in the reverse order and
  2284   has acquired the infix notation "!" as in "xs!n".
  2285 
  2286 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2287 
  2288 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2289   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2290 
  2291 * HOL/record: extensible records with schematic structural subtyping
  2292 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2293 still lacks various theorems and concrete record syntax;
  2294 
  2295 
  2296 *** HOLCF ***
  2297 
  2298 * removed "axioms" and "generated by" sections;
  2299 
  2300 * replaced "ops" section by extended "consts" section, which is capable of
  2301   handling the continuous function space "->" directly;
  2302 
  2303 * domain package:
  2304   . proves theorems immediately and stores them in the theory,
  2305   . creates hierachical name space,
  2306   . now uses normal mixfix annotations (instead of cinfix...),
  2307   . minor changes to some names and values (for consistency),
  2308   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2309   . separator between mutual domain defs: changed "," to "and",
  2310   . improved handling of sort constraints;  now they have to
  2311     appear on the left-hand side of the equations only;
  2312 
  2313 * fixed LAM <x,y,zs>.b syntax;
  2314 
  2315 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2316 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2317 
  2318 
  2319 *** FOL and ZF ***
  2320 
  2321 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2322   with `addloop' of the simplifier to faciliate case splitting in premises.
  2323 
  2324 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2325 in HOL, they strip ALL and --> from proved theorems;
  2326 
  2327 
  2328 
  2329 New in Isabelle94-8 (May 1997)
  2330 ------------------------------
  2331 
  2332 *** General Changes ***
  2333 
  2334 * new utilities to build / run / maintain Isabelle etc. (in parts
  2335 still somewhat experimental); old Makefiles etc. still functional;
  2336 
  2337 * new 'Isabelle System Manual';
  2338 
  2339 * INSTALL text, together with ./configure and ./build scripts;
  2340 
  2341 * reimplemented type inference for greater efficiency, better error
  2342 messages and clean internal interface;
  2343 
  2344 * prlim command for dealing with lots of subgoals (an easier way of
  2345 setting goals_limit);
  2346 
  2347 
  2348 *** Syntax ***
  2349 
  2350 * supports alternative (named) syntax tables (parser and pretty
  2351 printer); internal interface is provided by add_modesyntax(_i);
  2352 
  2353 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2354 be used in conjunction with the Isabelle symbol font; uses the
  2355 "symbols" syntax table;
  2356 
  2357 * added token_translation interface (may translate name tokens in
  2358 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2359 the current print_mode); IMPORTANT: user print translation functions
  2360 are responsible for marking newly introduced bounds
  2361 (Syntax.mark_boundT);
  2362 
  2363 * token translations for modes "xterm" and "xterm_color" that display
  2364 names in bold, underline etc. or colors (which requires a color
  2365 version of xterm);
  2366 
  2367 * infixes may now be declared with names independent of their syntax;
  2368 
  2369 * added typed_print_translation (like print_translation, but may
  2370 access type of constant);
  2371 
  2372 
  2373 *** Classical Reasoner ***
  2374 
  2375 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2376 some limitations.  Blast_tac...
  2377   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2378   + ignores elimination rules that don't have the correct format
  2379         (the conclusion MUST be a formula variable)
  2380   + ignores types, which can make HOL proofs fail
  2381   + rules must not require higher-order unification, e.g. apply_type in ZF
  2382     [message "Function Var's argument not a bound variable" relates to this]
  2383   + its proof strategy is more general but can actually be slower
  2384 
  2385 * substitution with equality assumptions no longer permutes other
  2386 assumptions;
  2387 
  2388 * minor changes in semantics of addafter (now called addaltern); renamed
  2389 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2390 (and access functions for it);
  2391 
  2392 * improved combination of classical reasoner and simplifier:
  2393   + functions for handling clasimpsets
  2394   + improvement of addss: now the simplifier is called _after_ the
  2395     safe steps.
  2396   + safe variant of addss called addSss: uses safe simplifications
  2397     _during_ the safe steps. It is more complete as it allows multiple
  2398     instantiations of unknowns (e.g. with slow_tac).
  2399 
  2400 *** Simplifier ***
  2401 
  2402 * added interface for simplification procedures (functions that
  2403 produce *proven* rewrite rules on the fly, depending on current
  2404 redex);
  2405 
  2406 * ordering on terms as parameter (used for ordered rewriting);
  2407 
  2408 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2409 
  2410 * the solver is now split into a safe and an unsafe part.
  2411 This should be invisible for the normal user, except that the
  2412 functions setsolver and addsolver have been renamed to setSolver and
  2413 addSolver; added safe_asm_full_simp_tac;
  2414 
  2415 
  2416 *** HOL ***
  2417 
  2418 * a generic induction tactic `induct_tac' which works for all datatypes and
  2419 also for type `nat';
  2420 
  2421 * a generic case distinction tactic `exhaust_tac' which works for all
  2422 datatypes and also for type `nat';
  2423 
  2424 * each datatype comes with a function `size';
  2425 
  2426 * patterns in case expressions allow tuple patterns as arguments to
  2427 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2428 
  2429 * primrec now also works with type nat;
  2430 
  2431 * recdef: a new declaration form, allows general recursive functions to be
  2432 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2433 
  2434 * the constant for negation has been renamed from "not" to "Not" to
  2435 harmonize with FOL, ZF, LK, etc.;
  2436 
  2437 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2438 infinite lists;
  2439 
  2440 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2441 
  2442 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2443 problems in commutative rings, using axiomatic type classes for + and *;
  2444 
  2445 * more examples in HOL/MiniML and HOL/Auth;
  2446 
  2447 * more default rewrite rules for quantifiers, union/intersection;
  2448 
  2449 * a new constant `arbitrary == @x.False';
  2450 
  2451 * HOLCF/IOA replaces old HOL/IOA;
  2452 
  2453 * HOLCF changes: derived all rules and arities
  2454   + axiomatic type classes instead of classes
  2455   + typedef instead of faking type definitions
  2456   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2457   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2458   + eliminated the types void, one, tr
  2459   + use unit lift and bool lift (with translations) instead of one and tr
  2460   + eliminated blift from Lift3.thy (use Def instead of blift)
  2461   all eliminated rules are derived as theorems --> no visible changes ;
  2462 
  2463 
  2464 *** ZF ***
  2465 
  2466 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2467 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2468 as ZF_cs addSIs [equalityI];
  2469 
  2470 
  2471 
  2472 New in Isabelle94-7 (November 96)
  2473 ---------------------------------
  2474 
  2475 * allowing negative levels (as offsets) in prlev and choplev;
  2476 
  2477 * super-linear speedup for large simplifications;
  2478 
  2479 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2480 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2481 FAIL); can suppress it using the command Delsimps (ex_simps @
  2482 all_simps); De Morgan laws are also now included, by default;
  2483 
  2484 * improved printing of ==>  :  ~:
  2485 
  2486 * new object-logic "Sequents" adds linear logic, while replacing LK
  2487 and Modal (thanks to Sara Kalvala);
  2488 
  2489 * HOL/Auth: correctness proofs for authentication protocols;
  2490 
  2491 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2492 examples on HOL/Auth);
  2493 
  2494 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2495 the rewriter and classical reasoner simultaneously;
  2496 
  2497 * function uresult no longer returns theorems in "standard" format;
  2498 regain previous version by: val uresult = standard o uresult;
  2499 
  2500 
  2501 
  2502 New in Isabelle94-6
  2503 -------------------
  2504 
  2505 * oracles -- these establish an interface between Isabelle and trusted
  2506 external reasoners, which may deliver results as theorems;
  2507 
  2508 * proof objects (in particular record all uses of oracles);
  2509 
  2510 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2511 
  2512 * "constdefs" section in theory files;
  2513 
  2514 * "primrec" section (HOL) no longer requires names;
  2515 
  2516 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2517 
  2518 
  2519 
  2520 New in Isabelle94-5
  2521 -------------------
  2522 
  2523 * reduced space requirements;
  2524 
  2525 * automatic HTML generation from theories;
  2526 
  2527 * theory files no longer require "..." (quotes) around most types;
  2528 
  2529 * new examples, including two proofs of the Church-Rosser theorem;
  2530 
  2531 * non-curried (1994) version of HOL is no longer distributed;
  2532 
  2533 
  2534 
  2535 New in Isabelle94-4
  2536 -------------------
  2537 
  2538 * greatly reduced space requirements;
  2539 
  2540 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2541 
  2542 * searchable theorem database (see the section "Retrieving theorems" on
  2543 page 8 of the Reference Manual);
  2544 
  2545 * new examples, including Grabczewski's monumental case study of the
  2546 Axiom of Choice;
  2547 
  2548 * The previous version of HOL renamed to Old_HOL;
  2549 
  2550 * The new version of HOL (previously called CHOL) uses a curried syntax
  2551 for functions.  Application looks like f a b instead of f(a,b);
  2552 
  2553 * Mutually recursive inductive definitions finally work in HOL;
  2554 
  2555 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2556 translates to the operator "split";
  2557 
  2558 
  2559 
  2560 New in Isabelle94-3
  2561 -------------------
  2562 
  2563 * new infix operator, addss, allowing the classical reasoner to
  2564 perform simplification at each step of its search.  Example:
  2565         fast_tac (cs addss ss)
  2566 
  2567 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2568 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2569 look like (a,b) instead of <a,b>;
  2570 
  2571 * PLEASE NOTE: CHOL will eventually replace HOL!
  2572 
  2573 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2574 It translates to the operator "split".  A new theory of integers is available;
  2575 
  2576 * In ZF, integer numerals now denote two's-complement binary integers.
  2577 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2578 
  2579 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2580 of the Axiom of Choice;
  2581 
  2582 
  2583 
  2584 New in Isabelle94-2
  2585 -------------------
  2586 
  2587 * Significantly faster resolution;
  2588 
  2589 * the different sections in a .thy file can now be mixed and repeated
  2590 freely;
  2591 
  2592 * Database of theorems for FOL, HOL and ZF.  New
  2593 commands including qed, qed_goal and bind_thm store theorems in the database.
  2594 
  2595 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2596 a given theory (thms_of), or find out what theory a theorem was proved in
  2597 (theory_of_thm);
  2598 
  2599 * Bugs fixed in the inductive definition and datatype packages;
  2600 
  2601 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2602 and HOL_dup_cs obsolete;
  2603 
  2604 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2605 have been removed;
  2606 
  2607 * Simpler definition of function space in ZF;
  2608 
  2609 * new results about cardinal and ordinal arithmetic in ZF;
  2610 
  2611 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2612 types;
  2613 
  2614 
  2615 $Id$