NEWS
author wenzelm
Sat May 01 22:28:51 2004 +0200 (2004-05-01)
changeset 14699 2c9b463044ec
parent 14698 7e4dec3fd515
child 14700 2f885b7e5ba7
permissions -rw-r--r--
tuned;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Pure: considerably improved version of 'constdefs' command.  Now
    10 performs automatic type-inference of declared constants; additional
    11 support for local structure declarations (cf. locales and HOL
    12 records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    13 to observe strictly sequential dependencies of definitions within a
    14 single 'constdefs' section; moreover, the declared name needs to be an
    15 identifier.  If all fails, consider to fall back on 'consts' and
    16 'defs' separately.
    17 
    18 * Pure: 'advanced' translation functions (parse_translation etc.) may
    19 depend on the signature of the theory context being presently used for
    20 parsing/printing, see also isar-ref manual.
    21 
    22 * Pure: improved indexed syntax and implicit structures.  First of
    23 all, indexed syntax provides a notational device for subscripted
    24 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    25 expressions.  Secondly, in a local context with structure
    26 declarations, number indexes \<^sub>n or the empty index (default
    27 number 1) refer to a certain fixed variable implicitly.  Typical
    28 applications of these concepts involve record types and locales.
    29 
    30 * Pure: tuned internal renaming of symbolic identifiers -- attach
    31 primes instead of base 26 numbers.
    32 
    33 
    34 *** HOLCF ***
    35 
    36 * HOLCF: discontinued special version of 'constdefs' (which used to
    37 support continuous functions) in favor of the general Pure one with
    38 full type-inference.
    39 
    40 
    41 
    42 New in Isabelle2004 (April 2004)
    43 --------------------------------
    44 
    45 *** General ***
    46 
    47 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
    48   Replaces linorder.ML.
    49 
    50 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
    51   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
    52   (\<a>...\<z>), are now considered normal letters, and can therefore
    53   be used anywhere where an ASCII letter (a...zA...Z) has until
    54   now. COMPATIBILITY: This obviously changes the parsing of some
    55   terms, especially where a symbol has been used as a binder, say
    56   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
    57   as an identifier.  Fix it by inserting a space around former
    58   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
    59   existing theory and ML files.
    60 
    61 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
    62 
    63 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now 
    64   allowed in identifiers. Similar to Greek letters \<^isub> is now considered 
    65   a normal (but invisible) letter. For multiple letter subscripts repeat 
    66   \<^isub> like this: x\<^isub>1\<^isub>2. 
    67 
    68 * Pure: There are now sub-/superscripts that can span more than one
    69   character. Text between \<^bsub> and \<^esub> is set in subscript in
    70   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
    71   superscript. The new control characters are not identifier parts.
    72 
    73 * Pure: Control-symbols of the form \<^raw:...> will literally print the
    74   content of "..." to the latex file instead of \isacntrl... . The "..."
    75   may consist of any printable characters excluding the end bracket >.
    76 
    77 * Pure: Using new Isar command "finalconsts" (or the ML functions
    78   Theory.add_finals or Theory.add_finals_i) it is now possible to
    79   declare constants "final", which prevents their being given a definition
    80   later.  It is useful for constants whose behaviour is fixed axiomatically
    81   rather than definitionally, such as the meta-logic connectives.
    82 
    83 * Pure: 'instance' now handles general arities with general sorts
    84   (i.e. intersections of classes),
    85 
    86 * Presentation: generated HTML now uses a CSS style sheet to make layout
    87   (somewhat) independent of content. It is copied from lib/html/isabelle.css. 
    88   It can be changed to alter the colors/layout of generated pages.
    89 
    90 
    91 *** Isar ***
    92 
    93 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
    94   cut_tac, subgoal_tac and thin_tac:
    95   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    96     locales are no longer forced to write Isar proof scripts.
    97     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    98     emulations.
    99   - INCOMPATIBILITY: names of variables to be instantiated may no
   100     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   101     This is consistent with the instantiation attribute "where".
   102 
   103 * Attributes "where" and "of":
   104   - Now take type variables of instantiated theorem into account when reading
   105     the instantiation string.  This fixes a bug that caused instantiated
   106     theorems to have too special types in some circumstances.
   107   - "where" permits explicit instantiations of type variables.
   108 
   109 * Calculation commands "moreover" and "also" no longer interfere with
   110   current facts ("this"), admitting arbitrary combinations with "then"
   111   and derived forms.
   112 
   113 * Locales:
   114   - Goal statements involving the context element "includes" no longer
   115     generate theorems with internal delta predicates (those ending on
   116     "_axioms") in the premise.
   117     Resolve particular premise with <locale>.intro to obtain old form.
   118   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   119     specification and "includes" elements in goal statement.
   120   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   121     [intro?] and [elim?] (respectively) by default.
   122   - Experimental command for instantiation of locales in proof contexts:
   123         instantiate <label>[<attrs>]: <loc>
   124     Instantiates locale <loc> and adds all its theorems to the current context
   125     taking into account their attributes.  Label and attrs are optional
   126     modifiers, like in theorem declarations.  If present, names of
   127     instantiated theorems are qualified with <label>, and the attributes
   128     <attrs> are applied after any attributes these theorems might have already.
   129       If the locale has assumptions, a chained fact of the form
   130     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   131     are derived.  The command does not support old-style locales declared
   132     with "locale (open)".
   133       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   134 
   135 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   136   (Isar) contexts.
   137 
   138 
   139 *** HOL ***
   140 
   141 * Proof import: new image HOL4 contains the imported library from
   142   the HOL4 system with about 2500 theorems. It is imported by
   143   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   144   can be used like any other Isabelle image.  See
   145   HOL/Import/HOL/README for more information.
   146 
   147 * Simplifier:
   148   - Much improved handling of linear and partial orders.
   149     Reasoners for linear and partial orders are set up for type classes
   150     "linorder" and "order" respectively, and are added to the default simpset
   151     as solvers.  This means that the simplifier can build transitivity chains
   152     to solve goals from the assumptions.
   153   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   154     of blast or auto after simplification become unnecessary because the goal
   155     is solved by simplification already.
   156 
   157 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws, 
   158     all proved in axiomatic type classes for semirings, rings and fields.
   159 
   160 * Numerics:
   161   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   162     now formalized using the Ring_and_Field theory mentioned above. 
   163   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   164     than before, because now they are set up once in a generic manner.
   165   - INCOMPATIBILITY: many type-specific arithmetic laws have gone. 
   166     Look for the general versions in Ring_and_Field (and Power if they concern
   167     exponentiation).
   168 
   169 * Type "rat" of the rational numbers is now available in HOL-Complex.
   170 
   171 * Records:
   172   - Record types are now by default printed with their type abbreviation
   173     instead of the list of all field types. This can be configured via
   174     the reference "print_record_type_abbr".
   175   - Simproc "record_upd_simproc" for simplification of multiple updates added 
   176     (not enabled by default).
   177   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   178     EX x. x = sel r to True (not enabled by default).
   179   - Tactic "record_split_simp_tac" to split and simplify records added.
   180  
   181 * 'specification' command added, allowing for definition by
   182   specification.  There is also an 'ax_specification' command that
   183   introduces the new constants axiomatically.
   184 
   185 * arith(_tac) is now able to generate counterexamples for reals as well.
   186 
   187 * HOL-Algebra: new locale "ring" for non-commutative rings.
   188 
   189 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   190   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   191 
   192 * HOL-Matrix: a first theory for matrices in HOL with an application of 
   193   matrix theory to linear programming.
   194 
   195 * Unions and Intersections:
   196   The x-symbol output syntax of UN and INT has been changed
   197   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   198   i.e. the index formulae has become a subscript, like in normal math.
   199   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   200   The subscript version is also accepted as input syntax.
   201 
   202 * Unions and Intersections over Intervals:
   203   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is 
   204   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A" 
   205   like in normal math, and corresponding versions for < and for intersection.
   206 
   207 * ML: the legacy theory structures Int and List have been removed. They had
   208   conflicted with ML Basis Library structures having the same names.
   209 
   210 * 'refute' command added to search for (finite) countermodels.  Only works
   211   for a fragment of HOL.  The installation of an external SAT solver is
   212   highly recommended.  See "HOL/Refute.thy" for details.
   213 
   214 * 'quickcheck' command: Allows to find counterexamples by evaluating
   215   formulae under an assignment of free variables to random values.
   216   In contrast to 'refute', it can deal with inductive datatypes,
   217   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   218   for examples.
   219 
   220 
   221 *** HOLCF ***
   222 
   223 * Streams now come with concatenation and are part of the HOLCF image
   224 
   225 
   226 
   227 New in Isabelle2003 (May 2003)
   228 ------------------------------
   229 
   230 *** General ***
   231 
   232 * Provers/simplifier:
   233 
   234   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   235     Assumptions are now subject to complete mutual simplification,
   236     not just from left to right. The simplifier now preserves
   237     the order of assumptions.
   238 
   239     Potential INCOMPATIBILITY:
   240 
   241     -- simp sometimes diverges where the old version did
   242        not, e.g. invoking simp on the goal
   243 
   244         [| P (f x); y = x; f x = f y |] ==> Q
   245 
   246        now gives rise to the infinite reduction sequence
   247 
   248         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   249 
   250        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   251        kind of problem.
   252 
   253     -- Tactics combining classical reasoner and simplification (such as auto)
   254        are also affected by this change, because many of them rely on
   255        simp. They may sometimes diverge as well or yield a different numbers
   256        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   257        in case of problems. Sometimes subsequent calls to the classical
   258        reasoner will fail because a preceeding call to the simplifier too
   259        eagerly simplified the goal, e.g. deleted redundant premises.
   260 
   261   - The simplifier trace now shows the names of the applied rewrite rules
   262 
   263   - You can limit the number of recursive invocations of the simplifier
   264     during conditional rewriting (where the simplifie tries to solve the
   265     conditions before applying the rewrite rule):
   266     ML "simp_depth_limit := n"
   267     where n is an integer. Thus you can force termination where previously
   268     the simplifier would diverge.
   269 
   270   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   271 
   272   - No longer aborts on failed congruence proof.  Instead, the
   273     congruence is ignored.
   274 
   275 * Pure: New generic framework for extracting programs from constructive
   276   proofs. See HOL/Extraction.thy for an example instantiation, as well
   277   as HOL/Extraction for some case studies.
   278 
   279 * Pure: The main goal of the proof state is no longer shown by default, only
   280 the subgoals. This behaviour is controlled by a new flag.
   281    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   282 (ML: Proof.show_main_goal).
   283 
   284 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   285 rules whose conclusion matches subgoal 1:
   286       PG menu: Isabelle/Isar -> Show me -> matching rules
   287 The rules are ordered by how closely they match the subgoal.
   288 In particular, rules that solve a subgoal outright are displayed first
   289 (or rather last, the way they are printed).
   290 (ML: ProofGeneral.print_intros())
   291 
   292 * Pure: New flag trace_unify_fail causes unification to print
   293 diagnostic information (PG: in trace buffer) when it fails. This is
   294 useful for figuring out why single step proofs like rule, erule or
   295 assumption failed.
   296 
   297 * Pure: Locale specifications now produce predicate definitions
   298 according to the body of text (covering assumptions modulo local
   299 definitions); predicate "loc_axioms" covers newly introduced text,
   300 while "loc" is cumulative wrt. all included locale expressions; the
   301 latter view is presented only on export into the global theory
   302 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   303 on the old view without predicates;
   304 
   305 * Pure: predefined locales "var" and "struct" are useful for sharing
   306 parameters (as in CASL, for example); just specify something like
   307 ``var x + var y + struct M'' as import;
   308 
   309 * Pure: improved thms_containing: proper indexing of facts instead of
   310 raw theorems; check validity of results wrt. current name space;
   311 include local facts of proof configuration (also covers active
   312 locales), cover fixed variables in index; may use "_" in term
   313 specification; an optional limit for the number of printed facts may
   314 be given (the default is 40);
   315 
   316 * Pure: disallow duplicate fact bindings within new-style theory files
   317 (batch-mode only);
   318 
   319 * Provers: improved induct method: assumptions introduced by case
   320 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   321 the goal statement); "foo" still refers to all facts collectively;
   322 
   323 * Provers: the function blast.overloaded has been removed: all constants
   324 are regarded as potentially overloaded, which improves robustness in exchange
   325 for slight decrease in efficiency;
   326 
   327 * Provers/linorder: New generic prover for transitivity reasoning over
   328 linear orders.  Note: this prover is not efficient!
   329 
   330 * Isar: preview of problems to finish 'show' now produce an error
   331 rather than just a warning (in interactive mode);
   332 
   333 
   334 *** HOL ***
   335 
   336 * arith(_tac)
   337 
   338  - Produces a counter example if it cannot prove a goal.
   339    Note that the counter example may be spurious if the goal is not a formula
   340    of quantifier-free linear arithmetic.
   341    In ProofGeneral the counter example appears in the trace buffer.
   342 
   343  - Knows about div k and mod k where k is a numeral of type nat or int.
   344 
   345  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   346    linear arithmetic fails. This takes account of quantifiers and divisibility.
   347    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   348 
   349 * simp's arithmetic capabilities have been enhanced a bit: it now
   350 takes ~= in premises into account (by performing a case split);
   351 
   352 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   353 are distributed over a sum of terms;
   354 
   355 * New tactic "trans_tac" and method "trans" instantiate
   356 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   357 "<=", "<" and "="). 
   358 
   359 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   360 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   361 
   362 * 'typedef' command has new option "open" to suppress the set
   363 definition;
   364 
   365 * functions Min and Max on finite sets have been introduced (theory
   366 Finite_Set);
   367 
   368 * attribute [symmetric] now works for relations as well; it turns
   369 (x,y) : R^-1 into (y,x) : R, and vice versa;
   370 
   371 * induct over a !!-quantified statement (say !!x1..xn):
   372   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   373 
   374 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   375 %x. None. Warning: empty_def now refers to the previously hidden definition
   376 of the empty set.
   377 
   378 * Algebra: formalization of classical algebra.  Intended as base for
   379 any algebraic development in Isabelle.  Currently covers group theory
   380 (up to Sylow's theorem) and ring theory (Universal Property of
   381 Univariate Polynomials).  Contributions welcome;
   382 
   383 * GroupTheory: deleted, since its material has been moved to Algebra;
   384 
   385 * Complex: new directory of the complex numbers with numeric constants, 
   386 nonstandard complex numbers, and some complex analysis, standard and 
   387 nonstandard (Jacques Fleuriot);
   388 
   389 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   390 
   391 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   392 Fleuriot);
   393 
   394 * Real/HahnBanach: updated and adapted to locales;
   395 
   396 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   397 Gray and Kramer);
   398 
   399 * UNITY: added the Meier-Sanders theory of progress sets;
   400 
   401 * MicroJava: bytecode verifier and lightweight bytecode verifier
   402 as abstract algorithms, instantiated to the JVM;
   403 
   404 * Bali: Java source language formalization. Type system, operational
   405 semantics, axiomatic semantics. Supported language features:
   406 classes, interfaces, objects,virtual methods, static methods,
   407 static/instance fields, arrays, access modifiers, definite
   408 assignment, exceptions.
   409 
   410 
   411 *** ZF ***
   412 
   413 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   414 universe, etc.);
   415 
   416 * Main ZF: virtually all theories converted to new-style format;
   417 
   418 
   419 *** ML ***
   420 
   421 * Pure: Tactic.prove provides sane interface for internal proofs;
   422 omits the infamous "standard" operation, so this is more appropriate
   423 than prove_goalw_cterm in many situations (e.g. in simprocs);
   424 
   425 * Pure: improved error reporting of simprocs;
   426 
   427 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   428 up simprocs;
   429 
   430 
   431 *** Document preparation ***
   432 
   433 * uses \par instead of \\ for line breaks in theory text. This may
   434 shift some page breaks in large documents. To get the old behaviour
   435 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   436 
   437 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   438 other packages
   439 
   440 * \<euro> now needs package babel/greek instead of marvosym (which
   441 broke \Rightarrow)
   442 
   443 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   444 textcomp package)
   445 
   446 
   447 
   448 New in Isabelle2002 (March 2002)
   449 --------------------------------
   450 
   451 *** Document preparation ***
   452 
   453 * greatly simplified document preparation setup, including more
   454 graceful interpretation of isatool usedir -i/-d/-D options, and more
   455 instructive isatool mkdir; users should basically be able to get
   456 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   457 users may run a separate document processing stage manually like this:
   458 "isatool usedir -D output HOL Test && isatool document Test/output";
   459 
   460 * theory dependency graph may now be incorporated into documents;
   461 isatool usedir -g true will produce session_graph.eps/.pdf for use
   462 with \includegraphics of LaTeX;
   463 
   464 * proper spacing of consecutive markup elements, especially text
   465 blocks after section headings;
   466 
   467 * support bold style (for single symbols only), input syntax is like
   468 this: "\<^bold>\<alpha>" or "\<^bold>A";
   469 
   470 * \<bullet> is now output as bold \cdot by default, which looks much
   471 better in printed text;
   472 
   473 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   474 note that these symbols are currently unavailable in Proof General /
   475 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   476 
   477 * isatool latex no longer depends on changed TEXINPUTS, instead
   478 isatool document copies the Isabelle style files to the target
   479 location;
   480 
   481 
   482 *** Isar ***
   483 
   484 * Pure/Provers: improved proof by cases and induction;
   485   - 'case' command admits impromptu naming of parameters (such as
   486     "case (Suc n)");
   487   - 'induct' method divinates rule instantiation from the inductive
   488     claim; no longer requires excessive ?P bindings for proper
   489     instantiation of cases;
   490   - 'induct' method properly enumerates all possibilities of set/type
   491     rules; as a consequence facts may be also passed through *type*
   492     rules without further ado;
   493   - 'induct' method now derives symbolic cases from the *rulified*
   494     rule (before it used to rulify cases stemming from the internal
   495     atomized version); this means that the context of a non-atomic
   496     statement becomes is included in the hypothesis, avoiding the
   497     slightly cumbersome show "PROP ?case" form;
   498   - 'induct' may now use elim-style induction rules without chaining
   499     facts, using ``missing'' premises from the goal state; this allows
   500     rules stemming from inductive sets to be applied in unstructured
   501     scripts, while still benefitting from proper handling of non-atomic
   502     statements; NB: major inductive premises need to be put first, all
   503     the rest of the goal is passed through the induction;
   504   - 'induct' proper support for mutual induction involving non-atomic
   505     rule statements (uses the new concept of simultaneous goals, see
   506     below);
   507   - append all possible rule selections, but only use the first
   508     success (no backtracking);
   509   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   510   - undeclared rule case names default to numbers 1, 2, 3, ...;
   511   - added 'print_induct_rules' (covered by help item in recent Proof
   512     General versions);
   513   - moved induct/cases attributes to Pure, methods to Provers;
   514   - generic method setup instantiated for FOL and HOL;
   515 
   516 * Pure: support multiple simultaneous goal statements, for example
   517 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   518 meta-level mechanism, this acts as if several individual goals had
   519 been stated separately; in particular common proof methods need to be
   520 repeated in order to cover all claims; note that a single elimination
   521 step is *not* sufficient to establish the two conjunctions, so this
   522 fails:
   523 
   524   assume "A & B" then have A and B ..   (*".." fails*)
   525 
   526 better use "obtain" in situations as above; alternative refer to
   527 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   528 
   529 * Pure: proper integration with ``locales''; unlike the original
   530 version by Florian Kammüller, Isar locales package high-level proof
   531 contexts rather than raw logical ones (e.g. we admit to include
   532 attributes everywhere); operations on locales include merge and
   533 rename; support for implicit arguments (``structures''); simultaneous
   534 type-inference over imports and text; see also HOL/ex/Locales.thy for
   535 some examples;
   536 
   537 * Pure: the following commands have been ``localized'', supporting a
   538 target locale specification "(in name)": 'lemma', 'theorem',
   539 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   540 stored both within the locale and at the theory level (exported and
   541 qualified by the locale name);
   542 
   543 * Pure: theory goals may now be specified in ``long'' form, with
   544 ad-hoc contexts consisting of arbitrary locale elements. for example
   545 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   546 definitions may be given, too); the result is a meta-level rule with
   547 the context elements being discharged in the obvious way;
   548 
   549 * Pure: new proof command 'using' allows to augment currently used
   550 facts after a goal statement ('using' is syntactically analogous to
   551 'apply', but acts on the goal's facts only); this allows chained facts
   552 to be separated into parts given before and after a claim, as in
   553 ``from a and b have C using d and e <proof>'';
   554 
   555 * Pure: renamed "antecedent" case to "rule_context";
   556 
   557 * Pure: new 'judgment' command records explicit information about the
   558 object-logic embedding (used by several tools internally); no longer
   559 use hard-wired "Trueprop";
   560 
   561 * Pure: added 'corollary' command;
   562 
   563 * Pure: fixed 'token_translation' command;
   564 
   565 * Pure: removed obsolete 'exported' attribute;
   566 
   567 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   568 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   569 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   570 
   571 * Pure: method 'atomize' presents local goal premises as object-level
   572 statements (atomic meta-level propositions); setup controlled via
   573 rewrite rules declarations of 'atomize' attribute; example
   574 application: 'induct' method with proper rule statements in improper
   575 proof *scripts*;
   576 
   577 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   578 now consider the syntactic context of assumptions, giving a better
   579 chance to get type-inference of the arguments right (this is
   580 especially important for locales);
   581 
   582 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   583 mode;
   584 
   585 * Pure/obtain: the formal conclusion "thesis", being marked as
   586 ``internal'', may no longer be reference directly in the text;
   587 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   588 situations;
   589 
   590 * Pure: generic 'sym' attribute which declares a rule both as pure
   591 'elim?' and for the 'symmetric' operation;
   592 
   593 * Pure: marginal comments ``--'' may now occur just anywhere in the
   594 text; the fixed correlation with particular command syntax has been
   595 discontinued;
   596 
   597 * Pure: new method 'rules' is particularly well-suited for proof
   598 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   599 but often produces more compact proof terms with less detours;
   600 
   601 * Pure/Provers/classical: simplified integration with pure rule
   602 attributes and methods; the classical "intro?/elim?/dest?"
   603 declarations coincide with the pure ones; the "rule" method no longer
   604 includes classically swapped intros; "intro" and "elim" methods no
   605 longer pick rules from the context; also got rid of ML declarations
   606 AddXIs/AddXEs/AddXDs; all of this has some potential for
   607 INCOMPATIBILITY;
   608 
   609 * Provers/classical: attribute 'swapped' produces classical inversions
   610 of introduction rules;
   611 
   612 * Provers/simplifier: 'simplified' attribute may refer to explicit
   613 rules instead of full simplifier context; 'iff' attribute handles
   614 conditional rules;
   615 
   616 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   617 
   618 * HOL: 'recdef' now fails on unfinished automated proofs, use
   619 "(permissive)" option to recover old behavior;
   620 
   621 * HOL: 'inductive' no longer features separate (collective) attributes
   622 for 'intros' (was found too confusing);
   623 
   624 * HOL: properly declared induction rules less_induct and
   625 wf_induct_rule;
   626 
   627 
   628 *** HOL ***
   629 
   630 * HOL: moved over to sane numeral syntax; the new policy is as
   631 follows:
   632 
   633   - 0 and 1 are polymorphic constants, which are defined on any
   634   numeric type (nat, int, real etc.);
   635 
   636   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   637   binary representation internally;
   638 
   639   - type nat has special constructor Suc, and generally prefers Suc 0
   640   over 1::nat and Suc (Suc 0) over 2::nat;
   641 
   642 This change may cause significant problems of INCOMPATIBILITY; here
   643 are some hints on converting existing sources:
   644 
   645   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   646   entities, so expressions involving "-" (unary or binary minus) need
   647   to be spaced properly;
   648 
   649   - existing occurrences of "1" may need to be constraint "1::nat" or
   650   even replaced by Suc 0; similar for old "2";
   651 
   652   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   653 
   654   - remove all special provisions on numerals in proofs;
   655 
   656 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   657 representation (depends on bin_arith_simps in the default context);
   658 
   659 * HOL: symbolic syntax for x^2 (numeral 2);
   660 
   661 * HOL: the class of all HOL types is now called "type" rather than
   662 "term"; INCOMPATIBILITY, need to adapt references to this type class
   663 in axclass/classes, instance/arities, and (usually rare) occurrences
   664 in typings (of consts etc.); internally the class is called
   665 "HOL.type", ML programs should refer to HOLogic.typeS;
   666 
   667 * HOL/record package improvements:
   668   - new derived operations "fields" to build a partial record section,
   669     "extend" to promote a fixed record to a record scheme, and
   670     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   671     declared as simp by default;
   672   - shared operations ("more", "fields", etc.) now need to be always
   673     qualified) --- potential INCOMPATIBILITY;
   674   - removed "make_scheme" operations (use "make" with "extend") --
   675     INCOMPATIBILITY;
   676   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   677   - provides cases/induct rules for use with corresponding Isar
   678     methods (for concrete records, record schemes, concrete more
   679     parts, and schematic more parts -- in that order);
   680   - internal definitions directly based on a light-weight abstract
   681     theory of product types over typedef rather than datatype;
   682 
   683 * HOL: generic code generator for generating executable ML code from
   684 specifications; specific support for HOL constructs such as inductive
   685 datatypes and sets, as well as recursive functions; can be invoked
   686 via 'generate_code' theory section;
   687 
   688 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   689 
   690 * HOL: consolidated and renamed several theories.  In particular:
   691 	Ord.thy has been absorbed into HOL.thy
   692 	String.thy has been absorbed into List.thy
   693  
   694 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   695 (beware of argument permutation!);
   696 
   697 * HOL: linorder_less_split superseded by linorder_cases;
   698 
   699 * HOL/List: "nodups" renamed to "distinct";
   700 
   701 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   702 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   703   - Ex_def has changed, now need to use some_eq_ex
   704 
   705 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   706 in this (rare) case use:
   707 
   708   delSWrapper "split_all_tac"
   709   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   710 
   711 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   712 MAY FAIL;
   713 
   714 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   715 Isabelle's type classes, ^ on functions and relations has too general
   716 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   717 necessary to attach explicit type constraints;
   718 
   719 * HOL/Relation: the prefix name of the infix "O" has been changed from
   720 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   721 renamed accordingly (eg "compI" -> "rel_compI").
   722 
   723 * HOL: syntax translations now work properly with numerals and records
   724 expressions;
   725 
   726 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   727 of "lam" -- INCOMPATIBILITY;
   728 
   729 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   730 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   731 renamed "Product_Type.unit";
   732 
   733 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   734 
   735 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   736 the "cases" method);
   737 
   738 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   739 Florian Kammüller);
   740 
   741 * HOL/IMP: updated and converted to new-style theory format; several
   742 parts turned into readable document, with proper Isar proof texts and
   743 some explanations (by Gerwin Klein);
   744 
   745 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   746 
   747 * HOL-Hyperreal is now a logic image;
   748 
   749 
   750 *** HOLCF ***
   751 
   752 * Isar: consts/constdefs supports mixfix syntax for continuous
   753 operations;
   754 
   755 * Isar: domain package adapted to new-style theory format, e.g. see
   756 HOLCF/ex/Dnat.thy;
   757 
   758 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   759 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   760 lift.induct_tac, always use UU instead of Undef;
   761 
   762 * HOLCF/IMP: updated and converted to new-style theory;
   763 
   764 
   765 *** ZF ***
   766 
   767 * Isar: proper integration of logic-specific tools and packages,
   768 including theory commands '(co)inductive', '(co)datatype',
   769 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   770 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   771 
   772 * theory Main no longer includes AC; for the Axiom of Choice, base
   773 your theory on Main_ZFC;
   774 
   775 * the integer library now covers quotients and remainders, with many
   776 laws relating division to addition, multiplication, etc.;
   777 
   778 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   779 typeless version of the formalism;
   780 
   781 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   782 format;
   783 
   784 * ZF/Induct: new directory for examples of inductive definitions,
   785 including theory Multiset for multiset orderings; converted to
   786 new-style theory format;
   787 
   788 * ZF: many new theorems about lists, ordinals, etc.;
   789 
   790 
   791 *** General ***
   792 
   793 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   794 variable proof controls level of detail: 0 = no proofs (only oracle
   795 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   796 also ref manual for further ML interfaces;
   797 
   798 * Pure/axclass: removed obsolete ML interface
   799 goal_subclass/goal_arity;
   800 
   801 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   802 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   803 separate tokens, so expressions involving minus need to be spaced
   804 properly;
   805 
   806 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   807 rather than "infixl" or "infixr";
   808 
   809 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   810 sort constraint specifications in type inference; e.g. "x::_::foo"
   811 ensures that the type of "x" is of sort "foo" (but not necessarily a
   812 type variable);
   813 
   814 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   815 control output of nested => (types); the default behavior is
   816 "type_brackets";
   817 
   818 * Pure/syntax: builtin parse translation for "_constify" turns valued
   819 tokens into AST constants;
   820 
   821 * Pure/syntax: prefer later declarations of translations and print
   822 translation functions; potential INCOMPATIBILITY: need to reverse
   823 multiple declarations for same syntax element constant;
   824 
   825 * Pure/show_hyps reset by default (in accordance to existing Isar
   826 practice);
   827 
   828 * Provers/classical: renamed addaltern to addafter, addSaltern to
   829 addSafter;
   830 
   831 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   832 as well;
   833 
   834 * system: tested support for MacOS X; should be able to get Isabelle +
   835 Proof General to work in a plain Terminal after installing Poly/ML
   836 (e.g. from the Isabelle distribution area) and GNU bash alone
   837 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   838 support requires further installations, e.g. from
   839 http://fink.sourceforge.net/);
   840 
   841 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   842 
   843 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   844 of 40 MB), cf. ML_OPTIONS;
   845 
   846 * system: Proof General keywords specification is now part of the
   847 Isabelle distribution (see etc/isar-keywords.el);
   848 
   849 * system: support for persistent Proof General sessions (refrain from
   850 outdating all loaded theories on startup); user may create writable
   851 logic images like this: ``isabelle -q HOL Test'';
   852 
   853 * system: smart selection of Isabelle process versus Isabelle
   854 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   855 run both "isabelle" and "Isabelle" even if file names are badly
   856 damaged (executable inspects the case of the first letter of its own
   857 name); added separate "isabelle-process" and "isabelle-interface";
   858 
   859 * system: refrain from any attempt at filtering input streams; no
   860 longer support ``8bit'' encoding of old isabelle font, instead proper
   861 iso-latin characters may now be used; the related isatools
   862 "symbolinput" and "nonascii" have disappeared as well;
   863 
   864 * system: removed old "xterm" interface (the print modes "xterm" and
   865 "xterm_color" are still available for direct use in a suitable
   866 terminal);
   867 
   868 
   869 
   870 New in Isabelle99-2 (February 2001)
   871 -----------------------------------
   872 
   873 *** Overview of INCOMPATIBILITIES ***
   874 
   875 * HOL: please note that theories in the Library and elsewhere often use the
   876 new-style (Isar) format; to refer to their theorems in an ML script you must
   877 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   878 
   879 * HOL: inductive package no longer splits induction rule aggressively,
   880 but only as far as specified by the introductions given; the old
   881 format may be recovered via ML function complete_split_rule or attribute
   882 'split_rule (complete)';
   883 
   884 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   885 gfp_Tarski to gfp_unfold;
   886 
   887 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   888 
   889 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   890 relation); infix "^^" has been renamed "``"; infix "``" has been
   891 renamed "`"; "univalent" has been renamed "single_valued";
   892 
   893 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   894 operation;
   895 
   896 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   897 
   898 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   899 
   900 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   901 consequence, it is no longer monotonic wrt. the local goal context
   902 (which is now passed through the inductive cases);
   903 
   904 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   905 \<gg> to \<ggreater>;
   906 
   907 
   908 *** Document preparation ***
   909 
   910 * \isabellestyle{NAME} selects version of Isabelle output (currently
   911 available: are "it" for near math-mode best-style output, "sl" for
   912 slanted text style, and "tt" for plain type-writer; if no
   913 \isabellestyle command is given, output is according to slanted
   914 type-writer);
   915 
   916 * support sub/super scripts (for single symbols only), input syntax is
   917 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   918 
   919 * some more standard symbols; see Appendix A of the system manual for
   920 the complete list of symbols defined in isabellesym.sty;
   921 
   922 * improved isabelle style files; more abstract symbol implementation
   923 (should now use \isamath{...} and \isatext{...} in custom symbol
   924 definitions);
   925 
   926 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   927 state; Note that presentation of goal states does not conform to
   928 actual human-readable proof documents.  Please do not include goal
   929 states into document output unless you really know what you are doing!
   930 
   931 * proper indentation of antiquoted output with proportional LaTeX
   932 fonts;
   933 
   934 * no_document ML operator temporarily disables LaTeX document
   935 generation;
   936 
   937 * isatool unsymbolize tunes sources for plain ASCII communication;
   938 
   939 
   940 *** Isar ***
   941 
   942 * Pure: Isar now suffers initial goal statements to contain unbound
   943 schematic variables (this does not conform to actual readable proof
   944 documents, due to unpredictable outcome and non-compositional proof
   945 checking); users who know what they are doing may use schematic goals
   946 for Prolog-style synthesis of proven results;
   947 
   948 * Pure: assumption method (an implicit finishing) now handles actual
   949 rules as well;
   950 
   951 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   952 initial goal, declare "that" only as Pure intro (only for single
   953 steps); the "that" rule assumption may now be involved in implicit
   954 finishing, thus ".." becomes a feasible for trivial obtains;
   955 
   956 * Pure: default proof step now includes 'intro_classes'; thus trivial
   957 instance proofs may be performed by "..";
   958 
   959 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   960 statements as well;
   961 
   962 * Pure: more robust selection of calculational rules;
   963 
   964 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   965 rule (as well as the assumption rule);
   966 
   967 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   968 lemmas, using the graph browser tool;
   969 
   970 * Pure: predict failure of "show" in interactive mode;
   971 
   972 * Pure: 'thms_containing' now takes actual terms as arguments;
   973 
   974 * HOL: improved method 'induct' --- now handles non-atomic goals
   975 (potential INCOMPATIBILITY); tuned error handling;
   976 
   977 * HOL: cases and induct rules now provide explicit hints about the
   978 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   979 any remaining facts are inserted into the goal verbatim;
   980 
   981 * HOL: local contexts (aka cases) may now contain term bindings as
   982 well; the 'cases' and 'induct' methods new provide a ?case binding for
   983 the result to be shown in each case;
   984 
   985 * HOL: added 'recdef_tc' command;
   986 
   987 * isatool convert assists in eliminating legacy ML scripts;
   988 
   989 
   990 *** HOL ***
   991 
   992 * HOL/Library: a collection of generic theories to be used together
   993 with main HOL; the theory loader path already includes this directory
   994 by default; the following existing theories have been moved here:
   995 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   996 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   997 
   998 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   999 modelling and verification task performed in Isabelle/HOL +
  1000 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1001 
  1002 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1003 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1004 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1005 'domain', this makes the theory consistent with mathematical
  1006 literature;
  1007 
  1008 * HOL basics: added overloaded operations "inverse" and "divide"
  1009 (infix "/"), syntax for generic "abs" operation, generic summation
  1010 operator \<Sum>;
  1011 
  1012 * HOL/typedef: simplified package, provide more useful rules (see also
  1013 HOL/subset.thy);
  1014 
  1015 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1016 now expressed as a proper nested rule (old-style tactic scripts may
  1017 require atomize_strip_tac to cope with non-atomic premises);
  1018 
  1019 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1020 to "split_conv" (old name still available for compatibility);
  1021 
  1022 * HOL: improved concrete syntax for strings (e.g. allows translation
  1023 rules with string literals);
  1024 
  1025 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1026  and Fleuriot's mechanization of analysis, including the transcendental
  1027  functions for the reals;
  1028 
  1029 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1030 
  1031 
  1032 *** CTT ***
  1033 
  1034 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1035 "lam" is displayed as TWO lambda-symbols
  1036 
  1037 * CTT: theory Main now available, containing everything (that is, Bool
  1038 and Arith);
  1039 
  1040 
  1041 *** General ***
  1042 
  1043 * Pure: the Simplifier has been implemented properly as a derived rule
  1044 outside of the actual kernel (at last!); the overall performance
  1045 penalty in practical applications is about 50%, while reliability of
  1046 the Isabelle inference kernel has been greatly improved;
  1047 
  1048 * print modes "brackets" and "no_brackets" control output of nested =>
  1049 (types) and ==> (props); the default behaviour is "brackets";
  1050 
  1051 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1052 as assumptions as well;
  1053 
  1054 * system: support Poly/ML 4.0;
  1055 
  1056 * system: isatool install handles KDE version 1 or 2;
  1057 
  1058 
  1059 
  1060 New in Isabelle99-1 (October 2000)
  1061 ----------------------------------
  1062 
  1063 *** Overview of INCOMPATIBILITIES ***
  1064 
  1065 * HOL: simplification of natural numbers is much changed; to partly
  1066 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1067 issue the following ML commands:
  1068 
  1069   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1070   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1071 
  1072 * HOL: simplification no longer dives into case-expressions; this is
  1073 controlled by "t.weak_case_cong" for each datatype t;
  1074 
  1075 * HOL: nat_less_induct renamed to less_induct;
  1076 
  1077 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1078 fixsome to patch .thy and .ML sources automatically;
  1079 
  1080   select_equality  -> some_equality
  1081   select_eq_Ex     -> some_eq_ex
  1082   selectI2EX       -> someI2_ex
  1083   selectI2         -> someI2
  1084   selectI          -> someI
  1085   select1_equality -> some1_equality
  1086   Eps_sym_eq       -> some_sym_eq_trivial
  1087   Eps_eq           -> some_eq_trivial
  1088 
  1089 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1090 
  1091 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1092 instead);
  1093 
  1094 * HOL: the recursion equations generated by 'recdef' are now called
  1095 f.simps instead of f.rules;
  1096 
  1097 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1098 
  1099 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1100 sometimes be needed;
  1101 
  1102 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1103 
  1104 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1105 
  1106 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1107 product is now "<*>" instead of "Times"; the lexicographic product is
  1108 now "<*lex*>" instead of "**";
  1109 
  1110 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1111 of main HOL, but was unused); better use HOL's datatype package;
  1112 
  1113 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1114 the old syntax may be recovered as follows:
  1115 
  1116   syntax (symbols)
  1117     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1118       (infixl "\\<oplus>" 100)
  1119 
  1120 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1121 
  1122 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1123 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1124 internally;
  1125 
  1126 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1127 changed from A/r to A//r;
  1128 
  1129 * ZF: new treatment of arithmetic (nat & int) may break some old
  1130 proofs;
  1131 
  1132 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1133 rulify -> rule_format, elimify -> elim_format, ...);
  1134 
  1135 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1136 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1137 should have to change intro!! to intro? only); replaced "delrule" by
  1138 "rule del";
  1139 
  1140 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1141 
  1142 * Provers: strengthened force_tac by using new first_best_tac;
  1143 
  1144 * LaTeX document preparation: several changes of isabelle.sty (see
  1145 lib/texinputs);
  1146 
  1147 
  1148 *** Document preparation ***
  1149 
  1150 * formal comments (text blocks etc.) in new-style theories may now
  1151 contain antiquotations of thm/prop/term/typ/text to be presented
  1152 according to latex print mode; concrete syntax is like this:
  1153 @{term[show_types] "f(x) = a + x"};
  1154 
  1155 * isatool mkdir provides easy setup of Isabelle session directories,
  1156 including proper document sources;
  1157 
  1158 * generated LaTeX sources are now deleted after successful run
  1159 (isatool document -c); may retain a copy somewhere else via -D option
  1160 of isatool usedir;
  1161 
  1162 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1163 style files, achieving self-contained LaTeX sources and simplifying
  1164 LaTeX debugging;
  1165 
  1166 * old-style theories now produce (crude) LaTeX output as well;
  1167 
  1168 * browser info session directories are now self-contained (may be put
  1169 on WWW server seperately); improved graphs of nested sessions; removed
  1170 graph for 'all sessions';
  1171 
  1172 * several improvements in isabelle style files; \isabellestyle{it}
  1173 produces fake math mode output; \isamarkupheader is now \section by
  1174 default; see lib/texinputs/isabelle.sty etc.;
  1175 
  1176 
  1177 *** Isar ***
  1178 
  1179 * Isar/Pure: local results and corresponding term bindings are now
  1180 subject to Hindley-Milner polymorphism (similar to ML); this
  1181 accommodates incremental type-inference very nicely;
  1182 
  1183 * Isar/Pure: new derived language element 'obtain' supports
  1184 generalized existence reasoning;
  1185 
  1186 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1187 support accumulation of results, without applying any rules yet;
  1188 useful to collect intermediate results without explicit name
  1189 references, and for use with transitivity rules with more than 2
  1190 premises;
  1191 
  1192 * Isar/Pure: scalable support for case-analysis type proofs: new
  1193 'case' language element refers to local contexts symbolically, as
  1194 produced by certain proof methods; internally, case names are attached
  1195 to theorems as "tags";
  1196 
  1197 * Isar/Pure: theory command 'hide' removes declarations from
  1198 class/type/const name spaces;
  1199 
  1200 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1201 indicate potential overloading;
  1202 
  1203 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1204 
  1205 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1206 "{a,b,c}" instead of {a,b,c};
  1207 
  1208 * Isar/Pure now provides its own version of intro/elim/dest
  1209 attributes; useful for building new logics, but beware of confusion
  1210 with the version in Provers/classical;
  1211 
  1212 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1213 case name 'antecedent';
  1214 
  1215 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1216 to the current context is now done automatically);
  1217 
  1218 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1219 for definining proof methods in ML;
  1220 
  1221 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1222 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1223 most cases, one should have to change intro!! to intro? only);
  1224 replaced "delrule" by "rule del";
  1225 
  1226 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1227 'symmetric' attribute (the latter supercedes [RS sym]);
  1228 
  1229 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1230 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1231 well (including splits);
  1232 
  1233 * Isar/Provers: Simplifier and Classical methods now support all kind
  1234 of modifiers used in the past, including 'cong', 'iff', etc.
  1235 
  1236 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1237 of Simplifier and Classical reasoner);
  1238 
  1239 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1240 now support named cases; major packages (inductive, datatype, primrec,
  1241 recdef) support case names and properly name parameters;
  1242 
  1243 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1244 monotonicity conditions are extracted to be proven at end of
  1245 calculations;
  1246 
  1247 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1248 method anyway;
  1249 
  1250 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1251 split_if split_if_asm; datatype package provides theorems foo.splits =
  1252 foo.split foo.split_asm for each datatype;
  1253 
  1254 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1255 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1256 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1257 use "(cases (simplified))" method in proper proof texts);
  1258 
  1259 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1260 
  1261 * Isar: names of theorems etc. may be natural numbers as well;
  1262 
  1263 * Isar: 'pr' command: optional arguments for goals_limit and
  1264 ProofContext.prems_limit; no longer prints theory contexts, but only
  1265 proof states;
  1266 
  1267 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1268 additional print modes to be specified; e.g. "pr(latex)" will print
  1269 proof state according to the Isabelle LaTeX style;
  1270 
  1271 * Isar: improved support for emulating tactic scripts, including proof
  1272 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1273 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1274 (for HOL datatypes);
  1275 
  1276 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1277 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1278 'proof method scripts' have to be in depth-first order;
  1279 
  1280 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1281 
  1282 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1283 should instead use individual commands for printing items
  1284 (print_commands, print_methods etc.);
  1285 
  1286 * Isar: added 'nothing' --- the empty list of theorems;
  1287 
  1288 
  1289 *** HOL ***
  1290 
  1291 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1292 corresponding virtual machine and a specification of its bytecode
  1293 verifier and a lightweight bytecode verifier, including proofs of
  1294 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1295 Cornelia Pusch (see also the homepage of project Bali at
  1296 http://isabelle.in.tum.de/Bali/);
  1297 
  1298 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1299 Clemens Ballarin;
  1300 
  1301 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1302 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1303 Rasmussen;
  1304 
  1305 * HOL/Lattice: fundamental concepts of lattice theory and order
  1306 structures, including duals, properties of bounds versus algebraic
  1307 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1308 Theorem for complete lattices etc.; may also serve as a demonstration
  1309 for abstract algebraic reasoning using axiomatic type classes, and
  1310 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1311 
  1312 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1313 von Oheimb;
  1314 
  1315 * HOL/IMPP: extension of IMP with local variables and mutually
  1316 recursive procedures, by David von Oheimb;
  1317 
  1318 * HOL/Lambda: converted into new-style theory and document;
  1319 
  1320 * HOL/ex/Multiquote: example of multiple nested quotations and
  1321 anti-quotations -- basically a generalized version of de-Bruijn
  1322 representation; very useful in avoiding lifting of operations;
  1323 
  1324 * HOL/record: added general record equality rule to simpset; fixed
  1325 select-update simplification procedure to handle extended records as
  1326 well; admit "r" as field name;
  1327 
  1328 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1329 other numeric types and also as the identity of groups, rings, etc.;
  1330 
  1331 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1332 Types nat and int belong to this axclass;
  1333 
  1334 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1335    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1336    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1337   two terms #m*u and #n*u are replaced by #(m+n)*u
  1338     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1339   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1340     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1341 
  1342 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1343 powerful prover for predicate logic but knows nothing of clasets; see
  1344 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1345 
  1346 * HOL: new version of "case_tac" subsumes both boolean case split and
  1347 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1348 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1349 
  1350 * HOL: simplification no longer dives into case-expressions: only the
  1351 selector expression is simplified, but not the remaining arms; to
  1352 enable full simplification of case-expressions for datatype t, you may
  1353 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1354 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1355 
  1356 * HOL/recdef: the recursion equations generated by 'recdef' for
  1357 function 'f' are now called f.simps instead of f.rules; if all
  1358 termination conditions are proved automatically, these simplification
  1359 rules are added to the simpset, as in primrec; rules may be named
  1360 individually as well, resulting in a separate list of theorems for
  1361 each equation;
  1362 
  1363 * HOL/While is a new theory that provides a while-combinator. It
  1364 permits the definition of tail-recursive functions without the
  1365 provision of a termination measure. The latter is necessary once the
  1366 invariant proof rule for while is applied.
  1367 
  1368 * HOL: new (overloaded) notation for the set of elements below/above
  1369 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1370 
  1371 * HOL: theorems impI, allI, ballI bound as "strip";
  1372 
  1373 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1374 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1375 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1376 
  1377 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1378 
  1379 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1380 main HOL, but was unused);
  1381 
  1382 * HOL: fewer consts declared as global (e.g. have to refer to
  1383 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1384 
  1385 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1386 in case of overlap with user translations (e.g. judgements over
  1387 tuples); (note that the underlying logical represenation is still
  1388 bogus);
  1389 
  1390 
  1391 *** ZF ***
  1392 
  1393 * ZF: simplification automatically cancels common terms in arithmetic
  1394 expressions over nat and int;
  1395 
  1396 * ZF: new treatment of nat to minimize type-checking: all operators
  1397 coerce their operands to a natural number using the function natify,
  1398 making the algebraic laws unconditional;
  1399 
  1400 * ZF: as above, for int: operators coerce their operands to an integer
  1401 using the function intify;
  1402 
  1403 * ZF: the integer library now contains many of the usual laws for the
  1404 orderings, including $<=, and monotonicity laws for $+ and $*;
  1405 
  1406 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1407 simplification;
  1408 
  1409 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1410 to the simplifier and classical reasoner simultaneously;
  1411 
  1412 
  1413 *** General ***
  1414 
  1415 * Provers: blast_tac now handles actual object-logic rules as
  1416 assumptions; note that auto_tac uses blast_tac internally as well;
  1417 
  1418 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1419 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1420 
  1421 * Provers: delrules now handles destruct rules as well (no longer need
  1422 explicit make_elim);
  1423 
  1424 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1425   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1426 use instead the strong form,
  1427   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1428 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1429 from destruct-rules;
  1430 
  1431 * Provers: Simplifier.easy_setup provides a fast path to basic
  1432 Simplifier setup for new object-logics;
  1433 
  1434 * Pure: AST translation rules no longer require constant head on LHS;
  1435 
  1436 * Pure: improved name spaces: ambiguous output is qualified; support
  1437 for hiding of names;
  1438 
  1439 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1440 XSYMBOL_HOME; no longer need to do manual configuration in most
  1441 situations;
  1442 
  1443 * system: compression of ML heaps images may now be controlled via -c
  1444 option of isabelle and isatool usedir (currently only observed by
  1445 Poly/ML);
  1446 
  1447 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1448 useful for remote X11);
  1449 
  1450 * system: provide TAGS file for Isabelle sources;
  1451 
  1452 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1453 order;
  1454 
  1455 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1456 timing flag supersedes proof_timing and Toplevel.trace;
  1457 
  1458 * ML: new combinators |>> and |>>> for incremental transformations
  1459 with secondary results (e.g. certain theory extensions):
  1460 
  1461 * ML: PureThy.add_defs gets additional argument to indicate potential
  1462 overloading (usually false);
  1463 
  1464 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1465 results;
  1466 
  1467 
  1468 
  1469 New in Isabelle99 (October 1999)
  1470 --------------------------------
  1471 
  1472 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1473 
  1474 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1475 are no longer simplified.  (This allows the simplifier to unfold recursive
  1476 functional programs.)  To restore the old behaviour, declare
  1477 
  1478     Delcongs [if_weak_cong];
  1479 
  1480 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1481 complement;
  1482 
  1483 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1484 
  1485 * HOL/datatype: mutual_induct_tac no longer exists --
  1486   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1487 
  1488 * HOL/typedef: fixed type inference for representing set; type
  1489 arguments now have to occur explicitly on the rhs as type constraints;
  1490 
  1491 * ZF: The con_defs part of an inductive definition may no longer refer
  1492 to constants declared in the same theory;
  1493 
  1494 * HOL, ZF: the function mk_cases, generated by the inductive
  1495 definition package, has lost an argument.  To simplify its result, it
  1496 uses the default simpset instead of a supplied list of theorems.
  1497 
  1498 * HOL/List: the constructors of type list are now Nil and Cons;
  1499 
  1500 * Simplifier: the type of the infix ML functions
  1501         setSSolver addSSolver setSolver addSolver
  1502 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1503 for packaging solvers. A solver is created via
  1504         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1505 where the string argument is only a comment.
  1506 
  1507 
  1508 *** Proof tools ***
  1509 
  1510 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1511 decision procedure for linear arithmetic. Currently it is used for
  1512 types `nat', `int', and `real' in HOL (see below); it can, should and
  1513 will be instantiated for other types and logics as well.
  1514 
  1515 * The simplifier now accepts rewrite rules with flexible heads, eg
  1516      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1517   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1518   matching.
  1519 
  1520 
  1521 *** General ***
  1522 
  1523 * New Isabelle/Isar subsystem provides an alternative to traditional
  1524 tactical theorem proving; together with the ProofGeneral/isar user
  1525 interface it offers an interactive environment for developing human
  1526 readable proof documents (Isar == Intelligible semi-automated
  1527 reasoning); for further information see isatool doc isar-ref,
  1528 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1529 
  1530 * improved and simplified presentation of theories: better HTML markup
  1531 (including colors), graph views in several sizes; isatool usedir now
  1532 provides a proper interface for user theories (via -P option); actual
  1533 document preparation based on (PDF)LaTeX is available as well (for
  1534 new-style theories only); see isatool doc system for more information;
  1535 
  1536 * native support for Proof General, both for classic Isabelle and
  1537 Isabelle/Isar;
  1538 
  1539 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1540 using the graph browser tool;
  1541 
  1542 * Isabelle manuals now also available as PDF;
  1543 
  1544 * theory loader rewritten from scratch (may not be fully
  1545 bug-compatible); old loadpath variable has been replaced by show_path,
  1546 add_path, del_path, reset_path functions; new operations such as
  1547 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1548 isatool doc ref);
  1549 
  1550 * improved isatool install: option -k creates KDE application icon,
  1551 option -p DIR installs standalone binaries;
  1552 
  1553 * added ML_PLATFORM setting (useful for cross-platform installations);
  1554 more robust handling of platform specific ML images for SML/NJ;
  1555 
  1556 * the settings environment is now statically scoped, i.e. it is never
  1557 created again in sub-processes invoked from isabelle, isatool, or
  1558 Isabelle;
  1559 
  1560 * path element specification '~~' refers to '$ISABELLE_HOME';
  1561 
  1562 * in locales, the "assumes" and "defines" parts may be omitted if
  1563 empty;
  1564 
  1565 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1566 long arrows);
  1567 
  1568 * new print_mode "HTML";
  1569 
  1570 * new flag show_tags controls display of tags of theorems (which are
  1571 basically just comments that may be attached by some tools);
  1572 
  1573 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1574 mode and goal output format:
  1575 
  1576 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1577 244c244
  1578 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1579 ---
  1580 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1581 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1582 181c181
  1583 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1584 ---
  1585 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1586 
  1587 * function bind_thms stores lists of theorems (cf. bind_thm);
  1588 
  1589 * new shorthand tactics ftac, eatac, datac, fatac;
  1590 
  1591 * qed (and friends) now accept "" as result name; in that case the
  1592 theorem is not stored, but proper checks and presentation of the
  1593 result still apply;
  1594 
  1595 * theorem database now also indexes constants "Trueprop", "all",
  1596 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1597 
  1598 
  1599 *** HOL ***
  1600 
  1601 ** HOL arithmetic **
  1602 
  1603 * There are now decision procedures for linear arithmetic over nat and
  1604 int:
  1605 
  1606 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1607 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1608 are treated as atomic; subformulae not involving type `nat' or `int'
  1609 are ignored; quantified subformulae are ignored unless they are
  1610 positive universal or negative existential. The tactic has to be
  1611 invoked by hand and can be a little bit slow. In particular, the
  1612 running time is exponential in the number of occurrences of `min' and
  1613 `max', and `-' on `nat'.
  1614 
  1615 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1616 (negated) (in)equalities among the premises and the conclusion into
  1617 account (i.e. no compound formulae) and does not know about `min' and
  1618 `max', and `-' on `nat'. It is fast and is used automatically by the
  1619 simplifier.
  1620 
  1621 NB: At the moment, these decision procedures do not cope with mixed
  1622 nat/int formulae where the two parts interact, such as `m < n ==>
  1623 int(m) < int(n)'.
  1624 
  1625 * HOL/Numeral provides a generic theory of numerals (encoded
  1626 efficiently as bit strings); setup for types nat/int/real is in place;
  1627 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1628 int, existing theories and proof scripts may require a few additional
  1629 type constraints;
  1630 
  1631 * integer division and remainder can now be performed on constant
  1632 arguments;
  1633 
  1634 * many properties of integer multiplication, division and remainder
  1635 are now available;
  1636 
  1637 * An interface to the Stanford Validity Checker (SVC) is available through the
  1638 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1639 are proved automatically.  SVC must be installed separately, and its results
  1640 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1641 invocation of the underlying oracle).  For SVC see
  1642   http://verify.stanford.edu/SVC
  1643 
  1644 * IsaMakefile: the HOL-Real target now builds an actual image;
  1645 
  1646 
  1647 ** HOL misc **
  1648 
  1649 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1650 (in Isabelle/Isar) -- by Gertrud Bauer;
  1651 
  1652 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1653 analysis for assembly languages with subtypes;
  1654 
  1655 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1656 -- avoids syntactic ambiguities and treats state, transition, and
  1657 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1658 changed syntax and (many) tactics;
  1659 
  1660 * HOL/inductive: Now also handles more general introduction rules such
  1661   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1662   theorems are now maintained within the theory (maintained via the
  1663   "mono" attribute);
  1664 
  1665 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1666   (using function types) such as
  1667 
  1668   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1669 
  1670 * HOL/record: record_simproc (part of the default simpset) takes care
  1671 of selectors applied to updated records; record_split_tac is no longer
  1672 part of the default claset; update_defs may now be removed from the
  1673 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1674 
  1675   claset_ref () := claset() addSWrapper record_split_wrapper;
  1676   Delsimprocs [record_simproc]
  1677 
  1678 * HOL/typedef: fixed type inference for representing set; type
  1679 arguments now have to occur explicitly on the rhs as type constraints;
  1680 
  1681 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1682 names rather than an ML expression;
  1683 
  1684 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1685 supplied later.  Program schemes can be defined, such as
  1686     "While B C s = (if B s then While B C (C s) else s)"
  1687 where the well-founded relation can be chosen after B and C have been given.
  1688 
  1689 * HOL/List: the constructors of type list are now Nil and Cons;
  1690 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1691 course, ML tools referring to List.list.op # etc. have to be adapted;
  1692 
  1693 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1694 disabled by default; run isabelle with option -m HOL to get back to
  1695 the original Gordon/HOL-style output;
  1696 
  1697 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1698 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1699 
  1700 * HOL basic syntax simplified (more orthogonal): all variants of
  1701 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1702 Eps operator is provided as well: "SOME x. P[x]";
  1703 
  1704 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1705 
  1706 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1707 thus available for user theories;
  1708 
  1709 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1710 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1711 time;
  1712 
  1713 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1714 several times and then mp;
  1715 
  1716 
  1717 *** LK ***
  1718 
  1719 * the notation <<...>> is now available as a notation for sequences of
  1720 formulas;
  1721 
  1722 * the simplifier is now installed
  1723 
  1724 * the axiom system has been generalized (thanks to Soren Heilmann)
  1725 
  1726 * the classical reasoner now has a default rule database
  1727 
  1728 
  1729 *** ZF ***
  1730 
  1731 * new primrec section allows primitive recursive functions to be given
  1732 directly (as in HOL) over datatypes and the natural numbers;
  1733 
  1734 * new tactics induct_tac and exhaust_tac for induction (or case
  1735 analysis) over datatypes and the natural numbers;
  1736 
  1737 * the datatype declaration of type T now defines the recursor T_rec;
  1738 
  1739 * simplification automatically does freeness reasoning for datatype
  1740 constructors;
  1741 
  1742 * automatic type-inference, with AddTCs command to insert new
  1743 type-checking rules;
  1744 
  1745 * datatype introduction rules are now added as Safe Introduction rules
  1746 to the claset;
  1747 
  1748 * the syntax "if P then x else y" is now available in addition to
  1749 if(P,x,y);
  1750 
  1751 
  1752 *** Internal programming interfaces ***
  1753 
  1754 * tuned simplifier trace output; new flag debug_simp;
  1755 
  1756 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1757 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1758 
  1759 * AxClass.axclass_tac lost the theory argument;
  1760 
  1761 * tuned current_goals_markers semantics: begin / end goal avoids
  1762 printing empty lines;
  1763 
  1764 * removed prs and prs_fn hook, which was broken because it did not
  1765 include \n in its semantics, forcing writeln to add one
  1766 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1767 string -> unit if you really want to output text without newline;
  1768 
  1769 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1770 plain output, interface builders may have to enable 'isabelle_font'
  1771 mode to get Isabelle font glyphs as before;
  1772 
  1773 * refined token_translation interface; INCOMPATIBILITY: output length
  1774 now of type real instead of int;
  1775 
  1776 * theory loader actions may be traced via new ThyInfo.add_hook
  1777 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1778 your own database of information attached to *whole* theories -- as
  1779 opposed to intra-theory data slots offered via TheoryDataFun;
  1780 
  1781 * proper handling of dangling sort hypotheses (at last!);
  1782 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1783 extra sort hypotheses that can be witnessed from the type signature;
  1784 the force_strip_shyps flag is gone, any remaining shyps are simply
  1785 left in the theorem (with a warning issued by strip_shyps_warning);
  1786 
  1787 
  1788 
  1789 New in Isabelle98-1 (October 1998)
  1790 ----------------------------------
  1791 
  1792 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1793 
  1794 * several changes of automated proof tools;
  1795 
  1796 * HOL: major changes to the inductive and datatype packages, including
  1797 some minor incompatibilities of theory syntax;
  1798 
  1799 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1800 called `inj_on';
  1801 
  1802 * HOL: removed duplicate thms in Arith:
  1803   less_imp_add_less  should be replaced by  trans_less_add1
  1804   le_imp_add_le      should be replaced by  trans_le_add1
  1805 
  1806 * HOL: unary minus is now overloaded (new type constraints may be
  1807 required);
  1808 
  1809 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1810 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1811 now taken as an integer constant.
  1812 
  1813 * Pure: ML function 'theory_of' renamed to 'theory';
  1814 
  1815 
  1816 *** Proof tools ***
  1817 
  1818 * Simplifier:
  1819   1. Asm_full_simp_tac is now more aggressive.
  1820      1. It will sometimes reorient premises if that increases their power to
  1821         simplify.
  1822      2. It does no longer proceed strictly from left to right but may also
  1823         rotate premises to achieve further simplification.
  1824      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1825      old Asm_full_simp_tac in that it does not rotate premises.
  1826   2. The simplifier now knows a little bit about nat-arithmetic.
  1827 
  1828 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1829 allows for selected deletion of wrappers, by introduction of names for
  1830 wrapper functionals.  This implies that addbefore, addSbefore,
  1831 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1832 and that adding two tactics with the same name overwrites the first
  1833 one (emitting a warning).
  1834   type wrapper = (int -> tactic) -> (int -> tactic)
  1835   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1836   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1837   delWrapper, delSWrapper: claset *  string            -> claset
  1838   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1839 
  1840 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1841 semantics; addbefore now affects only the unsafe part of step_tac
  1842 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1843 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1844 by Force_tac;
  1845 
  1846 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1847 compWrapper; added safe wrapper (and access functions for it);
  1848 
  1849 * HOL/split_all_tac is now much faster and fails if there is nothing
  1850 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1851 and the names of the automatically generated variables have changed.
  1852 split_all_tac has moved within claset() from unsafe wrappers to safe
  1853 wrappers, which means that !!-bound variables are split much more
  1854 aggressively, and safe_tac and clarify_tac now split such variables.
  1855 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1856 Note: the same holds for record_split_tac, which does the job of
  1857 split_all_tac for record fields.
  1858 
  1859 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1860 permanently to the default simpset using Addsplits just like
  1861 Addsimps. They can be removed via Delsplits just like
  1862 Delsimps. Lower-case versions are also available.
  1863 
  1864 * HOL/Simplifier: The rule split_if is now part of the default
  1865 simpset. This means that the simplifier will eliminate all occurrences
  1866 of if-then-else in the conclusion of a goal. To prevent this, you can
  1867 either remove split_if completely from the default simpset by
  1868 `Delsplits [split_if]' or remove it in a specific call of the
  1869 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1870 other case splitting rules to/from the default simpset: every datatype
  1871 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1872 t is the name of the datatype).
  1873 
  1874 * Classical reasoner / Simplifier combination: new force_tac (and
  1875 derivatives Force_tac, force) combines rewriting and classical
  1876 reasoning (and whatever other tools) similarly to auto_tac, but is
  1877 aimed to solve the given subgoal completely.
  1878 
  1879 
  1880 *** General ***
  1881 
  1882 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1883 and `goalw': the theory is no longer needed as an explicit argument -
  1884 the current theory context is used; assumptions are no longer returned
  1885 at the ML-level unless one of them starts with ==> or !!; it is
  1886 recommended to convert to these new commands using isatool fixgoal
  1887 (backup your sources first!);
  1888 
  1889 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1890 the current theory context, and 'theory' to lookup stored theories;
  1891 
  1892 * new theory section 'locale' for declaring constants, assumptions and
  1893 definitions that have local scope;
  1894 
  1895 * new theory section 'nonterminals' for purely syntactic types;
  1896 
  1897 * new theory section 'setup' for generic ML setup functions
  1898 (e.g. package initialization);
  1899 
  1900 * the distribution now includes Isabelle icons: see
  1901 lib/logo/isabelle-{small,tiny}.xpm;
  1902 
  1903 * isatool install - install binaries with absolute references to
  1904 ISABELLE_HOME/bin;
  1905 
  1906 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1907 
  1908 * print mode 'emacs' reserved for Isamode;
  1909 
  1910 * support multiple print (ast) translations per constant name;
  1911 
  1912 * theorems involving oracles are now printed with a suffixed [!];
  1913 
  1914 
  1915 *** HOL ***
  1916 
  1917 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1918 
  1919 * HOL/inductive package reorganized and improved: now supports mutual
  1920 definitions such as
  1921 
  1922   inductive EVEN ODD
  1923     intrs
  1924       null "0 : EVEN"
  1925       oddI "n : EVEN ==> Suc n : ODD"
  1926       evenI "n : ODD ==> Suc n : EVEN"
  1927 
  1928 new theorem list "elims" contains an elimination rule for each of the
  1929 recursive sets; inductive definitions now handle disjunctive premises
  1930 correctly (also ZF);
  1931 
  1932 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1933 "mutual_induct" no longer exists - the induction rule is always
  1934 contained in "induct";
  1935 
  1936 
  1937 * HOL/datatype package re-implemented and greatly improved: now
  1938 supports mutually recursive datatypes such as
  1939 
  1940   datatype
  1941     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1942             | SUM ('a aexp) ('a aexp)
  1943             | DIFF ('a aexp) ('a aexp)
  1944             | NUM 'a
  1945   and
  1946     'a bexp = LESS ('a aexp) ('a aexp)
  1947             | AND ('a bexp) ('a bexp)
  1948             | OR ('a bexp) ('a bexp)
  1949 
  1950 as well as indirectly recursive datatypes such as
  1951 
  1952   datatype
  1953     ('a, 'b) term = Var 'a
  1954                   | App 'b ((('a, 'b) term) list)
  1955 
  1956 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1957 induction on mutually / indirectly recursive datatypes.
  1958 
  1959 Primrec equations are now stored in theory and can be accessed via
  1960 <function_name>.simps.
  1961 
  1962 INCOMPATIBILITIES:
  1963 
  1964   - Theories using datatypes must now have theory Datatype as an
  1965     ancestor.
  1966   - The specific <typename>.induct_tac no longer exists - use the
  1967     generic induct_tac instead.
  1968   - natE has been renamed to nat.exhaust - use exhaust_tac
  1969     instead of res_inst_tac ... natE. Note that the variable
  1970     names in nat.exhaust differ from the names in natE, this
  1971     may cause some "fragile" proofs to fail.
  1972   - The theorems split_<typename>_case and split_<typename>_case_asm
  1973     have been renamed to <typename>.split and <typename>.split_asm.
  1974   - Since default sorts of type variables are now handled correctly,
  1975     some datatype definitions may have to be annotated with explicit
  1976     sort constraints.
  1977   - Primrec definitions no longer require function name and type
  1978     of recursive argument.
  1979 
  1980 Consider using isatool fixdatatype to adapt your theories and proof
  1981 scripts to the new package (backup your sources first!).
  1982 
  1983 
  1984 * HOL/record package: considerably improved implementation; now
  1985 includes concrete syntax for record types, terms, updates; theorems
  1986 for surjective pairing and splitting !!-bound record variables; proof
  1987 support is as follows:
  1988 
  1989   1) standard conversions (selectors or updates applied to record
  1990 constructor terms) are part of the standard simpset;
  1991 
  1992   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1993 made part of standard simpset and claset via addIffs;
  1994 
  1995   3) a tactic for record field splitting (record_split_tac) is part of
  1996 the standard claset (addSWrapper);
  1997 
  1998 To get a better idea about these rules you may retrieve them via
  1999 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2000 the name of your record type.
  2001 
  2002 The split tactic 3) conceptually simplifies by the following rule:
  2003 
  2004   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2005 
  2006 Thus any record variable that is bound by meta-all will automatically
  2007 blow up into some record constructor term, consequently the
  2008 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2009 solve record problems automatically.
  2010 
  2011 
  2012 * reorganized the main HOL image: HOL/Integ and String loaded by
  2013 default; theory Main includes everything;
  2014 
  2015 * automatic simplification of integer sums and comparisons, using cancellation;
  2016 
  2017 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2018 
  2019 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2020 
  2021 * many new identities for unions, intersections, set difference, etc.;
  2022 
  2023 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2024 called split_if, split_split, split_sum_case and split_nat_case (to go
  2025 with add/delsplits);
  2026 
  2027 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2028 (?x::unit) = (); this is made part of the default simpset, which COULD
  2029 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2030 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2031 unit_abs_eta_conv is added in order to counter the effect of
  2032 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2033 %u.f();
  2034 
  2035 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2036 makes more sense);
  2037 
  2038 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2039   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2040   disjointness reasoning but breaking a few old proofs.
  2041 
  2042 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2043 to 'converse' from 'inverse' (for compatibility with ZF and some
  2044 literature);
  2045 
  2046 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2047 the well-founded relation;
  2048 
  2049 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2050     Compl A.  The "Compl" syntax remains available as input syntax for this
  2051     release ONLY.
  2052 
  2053 * HOL/Update: new theory of function updates:
  2054     f(a:=b) == %x. if x=a then b else f x
  2055 may also be iterated as in f(a:=b,c:=d,...);
  2056 
  2057 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2058 
  2059 * HOL/List:
  2060   - new function list_update written xs[i:=v] that updates the i-th
  2061     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2062   - new function `upt' written [i..j(] which generates the list
  2063     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2064     bound write [i..j], which is a shorthand for [i..j+1(].
  2065   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2066 
  2067 * HOL/Arith:
  2068   - removed 'pred' (predecessor) function;
  2069   - generalized some theorems about n-1;
  2070   - many new laws about "div" and "mod";
  2071   - new laws about greatest common divisors (see theory ex/Primes);
  2072 
  2073 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2074 instead of "inverse";
  2075 
  2076 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2077   of the multiset ordering;
  2078 
  2079 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2080   (not included by default);
  2081 
  2082 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2083 
  2084 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2085   programs, i.e. different program variables may have different types.
  2086 
  2087 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2088   [previously, this check worked only if the rewrite rule was unconditional]
  2089   Now rew can involve either definitions or equalities (either == or =).
  2090 
  2091 
  2092 *** ZF ***
  2093 
  2094 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2095   only the theorems proved on ZF.ML;
  2096 
  2097 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2098   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2099   disjointness reasoning but breaking a few old proofs.
  2100 
  2101 * ZF/Update: new theory of function updates
  2102     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2103   may also be iterated as in f(a:=b,c:=d,...);
  2104 
  2105 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2106 
  2107 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2108   [previously, this check worked only if the rewrite rule was unconditional]
  2109   Now rew can involve either definitions or equalities (either == or =).
  2110 
  2111 * case_tac provided for compatibility with HOL
  2112     (like the old excluded_middle_tac, but with subgoals swapped)
  2113 
  2114 
  2115 *** Internal programming interfaces ***
  2116 
  2117 * Pure: several new basic modules made available for general use, see
  2118 also src/Pure/README;
  2119 
  2120 * improved the theory data mechanism to support encapsulation (data
  2121 kind name replaced by private Object.kind, acting as authorization
  2122 key); new type-safe user interface via functor TheoryDataFun; generic
  2123 print_data function becomes basically useless;
  2124 
  2125 * removed global_names compatibility flag -- all theory declarations
  2126 are qualified by default;
  2127 
  2128 * module Pure/Syntax now offers quote / antiquote translation
  2129 functions (useful for Hoare logic etc. with implicit dependencies);
  2130 see HOL/ex/Antiquote for an example use;
  2131 
  2132 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2133 cterm -> thm;
  2134 
  2135 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2136 subgoal;
  2137 
  2138 * Display.print_goals function moved to Locale.print_goals;
  2139 
  2140 * standard print function for goals supports current_goals_markers
  2141 variable for marking begin of proof, end of proof, start of goal; the
  2142 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2143 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2144 for example;
  2145 
  2146 
  2147 
  2148 New in Isabelle98 (January 1998)
  2149 --------------------------------
  2150 
  2151 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2152 
  2153 * changed lexical syntax of terms / types: dots made part of long
  2154 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2155 
  2156 * simpset (and claset) reference variable replaced by functions
  2157 simpset / simpset_ref;
  2158 
  2159 * no longer supports theory aliases (via merge) and non-trivial
  2160 implicit merge of thms' signatures;
  2161 
  2162 * most internal names of constants changed due to qualified names;
  2163 
  2164 * changed Pure/Sequence interface (see Pure/seq.ML);
  2165 
  2166 
  2167 *** General Changes ***
  2168 
  2169 * hierachically structured name spaces (for consts, types, axms, thms
  2170 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2171 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2172 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2173 long_names for fully qualified output names; NOTE: ML programs
  2174 (special tactics, packages etc.) referring to internal names may have
  2175 to be adapted to cope with fully qualified names; in case of severe
  2176 backward campatibility problems try setting 'global_names' at compile
  2177 time to have enrything declared within a flat name space; one may also
  2178 fine tune name declarations in theories via the 'global' and 'local'
  2179 section;
  2180 
  2181 * reimplemented the implicit simpset and claset using the new anytype
  2182 data filed in signatures; references simpset:simpset ref etc. are
  2183 replaced by functions simpset:unit->simpset and
  2184 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2185 to patch your ML files accordingly;
  2186 
  2187 * HTML output now includes theory graph data for display with Java
  2188 applet or isatool browser; data generated automatically via isatool
  2189 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2190 
  2191 * defs may now be conditional; improved rewrite_goals_tac to handle
  2192 conditional equations;
  2193 
  2194 * defs now admits additional type arguments, using TYPE('a) syntax;
  2195 
  2196 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2197 creates a new theory node; implicit merge of thms' signatures is
  2198 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2199 transfer:theory->thm->thm in (rare) cases;
  2200 
  2201 * improved handling of draft signatures / theories; draft thms (and
  2202 ctyps, cterms) are automatically promoted to real ones;
  2203 
  2204 * slightly changed interfaces for oracles: admit many per theory, named
  2205 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2206 
  2207 * print_goals: optional output of const types (set show_consts and
  2208 show_types);
  2209 
  2210 * improved output of warnings (###) and errors (***);
  2211 
  2212 * subgoal_tac displays a warning if the new subgoal has type variables;
  2213 
  2214 * removed old README and Makefiles;
  2215 
  2216 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2217 
  2218 * removed obsolete init_pps and init_database;
  2219 
  2220 * deleted the obsolete tactical STATE, which was declared by
  2221     fun STATE tacfun st = tacfun st st;
  2222 
  2223 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2224 (which abbreviates $HOME);
  2225 
  2226 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2227 use isatool fixseq to adapt your ML programs (this works for fully
  2228 qualified references to the Sequence structure only!);
  2229 
  2230 * use_thy no longer requires writable current directory; it always
  2231 reloads .ML *and* .thy file, if either one is out of date;
  2232 
  2233 
  2234 *** Classical Reasoner ***
  2235 
  2236 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2237 tactics that use classical reasoning to simplify a subgoal without
  2238 splitting it into several subgoals;
  2239 
  2240 * Safe_tac: like safe_tac but uses the default claset;
  2241 
  2242 
  2243 *** Simplifier ***
  2244 
  2245 * added simplification meta rules:
  2246     (asm_)(full_)simplify: simpset -> thm -> thm;
  2247 
  2248 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2249 logics (again);
  2250 
  2251 * added prems argument to simplification procedures;
  2252 
  2253 * HOL, FOL, ZF: added infix function `addsplits':
  2254   instead of `<simpset> setloop (split_tac <thms>)'
  2255   you can simply write `<simpset> addsplits <thms>'
  2256 
  2257 
  2258 *** Syntax ***
  2259 
  2260 * TYPE('a) syntax for type reflection terms;
  2261 
  2262 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2263 
  2264 * pretty printer: changed order of mixfix annotation preference (again!);
  2265 
  2266 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2267 
  2268 
  2269 *** HOL ***
  2270 
  2271 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2272   with `addloop' of the simplifier to faciliate case splitting in premises.
  2273 
  2274 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2275 
  2276 * HOL/Auth: new protocol proofs including some for the Internet
  2277   protocol TLS;
  2278 
  2279 * HOL/Map: new theory of `maps' a la VDM;
  2280 
  2281 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2282 cancelling out common nat summands from =, <, <= (in)equalities, or
  2283 differences; simplification procedures nat_cancel_factor for
  2284 cancelling common factor from =, <, <= (in)equalities over natural
  2285 sums; nat_cancel contains both kinds of procedures, it is installed by
  2286 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2287 
  2288 * HOL/simplifier: terms of the form
  2289   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2290   are rewritten to
  2291   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2292   and those of the form
  2293   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2294   are rewritten to
  2295   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2296 
  2297 * HOL/datatype
  2298   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2299 
  2300   P(t_case f1 ... fn x) =
  2301      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2302         ...
  2303        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2304      )
  2305 
  2306   and a theorem `split_t_case_asm' of the form
  2307 
  2308   P(t_case f1 ... fn x) =
  2309     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2310         ...
  2311        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2312      )
  2313   which can be added to a simpset via `addsplits'. The existing theorems
  2314   expand_list_case and expand_option_case have been renamed to
  2315   split_list_case and split_option_case.
  2316 
  2317 * HOL/Arithmetic:
  2318   - `pred n' is automatically converted to `n-1'.
  2319     Users are strongly encouraged not to use `pred' any longer,
  2320     because it will disappear altogether at some point.
  2321   - Users are strongly encouraged to write "0 < n" rather than
  2322     "n ~= 0". Theorems and proof tools have been modified towards this
  2323     `standard'.
  2324 
  2325 * HOL/Lists:
  2326   the function "set_of_list" has been renamed "set" (and its theorems too);
  2327   the function "nth" now takes its arguments in the reverse order and
  2328   has acquired the infix notation "!" as in "xs!n".
  2329 
  2330 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2331 
  2332 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2333   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2334 
  2335 * HOL/record: extensible records with schematic structural subtyping
  2336 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2337 still lacks various theorems and concrete record syntax;
  2338 
  2339 
  2340 *** HOLCF ***
  2341 
  2342 * removed "axioms" and "generated by" sections;
  2343 
  2344 * replaced "ops" section by extended "consts" section, which is capable of
  2345   handling the continuous function space "->" directly;
  2346 
  2347 * domain package:
  2348   . proves theorems immediately and stores them in the theory,
  2349   . creates hierachical name space,
  2350   . now uses normal mixfix annotations (instead of cinfix...),
  2351   . minor changes to some names and values (for consistency),
  2352   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2353   . separator between mutual domain defs: changed "," to "and",
  2354   . improved handling of sort constraints;  now they have to
  2355     appear on the left-hand side of the equations only;
  2356 
  2357 * fixed LAM <x,y,zs>.b syntax;
  2358 
  2359 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2360 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2361 
  2362 
  2363 *** FOL and ZF ***
  2364 
  2365 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2366   with `addloop' of the simplifier to faciliate case splitting in premises.
  2367 
  2368 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2369 in HOL, they strip ALL and --> from proved theorems;
  2370 
  2371 
  2372 
  2373 New in Isabelle94-8 (May 1997)
  2374 ------------------------------
  2375 
  2376 *** General Changes ***
  2377 
  2378 * new utilities to build / run / maintain Isabelle etc. (in parts
  2379 still somewhat experimental); old Makefiles etc. still functional;
  2380 
  2381 * new 'Isabelle System Manual';
  2382 
  2383 * INSTALL text, together with ./configure and ./build scripts;
  2384 
  2385 * reimplemented type inference for greater efficiency, better error
  2386 messages and clean internal interface;
  2387 
  2388 * prlim command for dealing with lots of subgoals (an easier way of
  2389 setting goals_limit);
  2390 
  2391 
  2392 *** Syntax ***
  2393 
  2394 * supports alternative (named) syntax tables (parser and pretty
  2395 printer); internal interface is provided by add_modesyntax(_i);
  2396 
  2397 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2398 be used in conjunction with the Isabelle symbol font; uses the
  2399 "symbols" syntax table;
  2400 
  2401 * added token_translation interface (may translate name tokens in
  2402 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2403 the current print_mode); IMPORTANT: user print translation functions
  2404 are responsible for marking newly introduced bounds
  2405 (Syntax.mark_boundT);
  2406 
  2407 * token translations for modes "xterm" and "xterm_color" that display
  2408 names in bold, underline etc. or colors (which requires a color
  2409 version of xterm);
  2410 
  2411 * infixes may now be declared with names independent of their syntax;
  2412 
  2413 * added typed_print_translation (like print_translation, but may
  2414 access type of constant);
  2415 
  2416 
  2417 *** Classical Reasoner ***
  2418 
  2419 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2420 some limitations.  Blast_tac...
  2421   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2422   + ignores elimination rules that don't have the correct format
  2423         (the conclusion MUST be a formula variable)
  2424   + ignores types, which can make HOL proofs fail
  2425   + rules must not require higher-order unification, e.g. apply_type in ZF
  2426     [message "Function Var's argument not a bound variable" relates to this]
  2427   + its proof strategy is more general but can actually be slower
  2428 
  2429 * substitution with equality assumptions no longer permutes other
  2430 assumptions;
  2431 
  2432 * minor changes in semantics of addafter (now called addaltern); renamed
  2433 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2434 (and access functions for it);
  2435 
  2436 * improved combination of classical reasoner and simplifier:
  2437   + functions for handling clasimpsets
  2438   + improvement of addss: now the simplifier is called _after_ the
  2439     safe steps.
  2440   + safe variant of addss called addSss: uses safe simplifications
  2441     _during_ the safe steps. It is more complete as it allows multiple
  2442     instantiations of unknowns (e.g. with slow_tac).
  2443 
  2444 *** Simplifier ***
  2445 
  2446 * added interface for simplification procedures (functions that
  2447 produce *proven* rewrite rules on the fly, depending on current
  2448 redex);
  2449 
  2450 * ordering on terms as parameter (used for ordered rewriting);
  2451 
  2452 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2453 
  2454 * the solver is now split into a safe and an unsafe part.
  2455 This should be invisible for the normal user, except that the
  2456 functions setsolver and addsolver have been renamed to setSolver and
  2457 addSolver; added safe_asm_full_simp_tac;
  2458 
  2459 
  2460 *** HOL ***
  2461 
  2462 * a generic induction tactic `induct_tac' which works for all datatypes and
  2463 also for type `nat';
  2464 
  2465 * a generic case distinction tactic `exhaust_tac' which works for all
  2466 datatypes and also for type `nat';
  2467 
  2468 * each datatype comes with a function `size';
  2469 
  2470 * patterns in case expressions allow tuple patterns as arguments to
  2471 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2472 
  2473 * primrec now also works with type nat;
  2474 
  2475 * recdef: a new declaration form, allows general recursive functions to be
  2476 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2477 
  2478 * the constant for negation has been renamed from "not" to "Not" to
  2479 harmonize with FOL, ZF, LK, etc.;
  2480 
  2481 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2482 infinite lists;
  2483 
  2484 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2485 
  2486 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2487 problems in commutative rings, using axiomatic type classes for + and *;
  2488 
  2489 * more examples in HOL/MiniML and HOL/Auth;
  2490 
  2491 * more default rewrite rules for quantifiers, union/intersection;
  2492 
  2493 * a new constant `arbitrary == @x.False';
  2494 
  2495 * HOLCF/IOA replaces old HOL/IOA;
  2496 
  2497 * HOLCF changes: derived all rules and arities
  2498   + axiomatic type classes instead of classes
  2499   + typedef instead of faking type definitions
  2500   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2501   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2502   + eliminated the types void, one, tr
  2503   + use unit lift and bool lift (with translations) instead of one and tr
  2504   + eliminated blift from Lift3.thy (use Def instead of blift)
  2505   all eliminated rules are derived as theorems --> no visible changes ;
  2506 
  2507 
  2508 *** ZF ***
  2509 
  2510 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2511 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2512 as ZF_cs addSIs [equalityI];
  2513 
  2514 
  2515 
  2516 New in Isabelle94-7 (November 96)
  2517 ---------------------------------
  2518 
  2519 * allowing negative levels (as offsets) in prlev and choplev;
  2520 
  2521 * super-linear speedup for large simplifications;
  2522 
  2523 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2524 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2525 FAIL); can suppress it using the command Delsimps (ex_simps @
  2526 all_simps); De Morgan laws are also now included, by default;
  2527 
  2528 * improved printing of ==>  :  ~:
  2529 
  2530 * new object-logic "Sequents" adds linear logic, while replacing LK
  2531 and Modal (thanks to Sara Kalvala);
  2532 
  2533 * HOL/Auth: correctness proofs for authentication protocols;
  2534 
  2535 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2536 examples on HOL/Auth);
  2537 
  2538 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2539 the rewriter and classical reasoner simultaneously;
  2540 
  2541 * function uresult no longer returns theorems in "standard" format;
  2542 regain previous version by: val uresult = standard o uresult;
  2543 
  2544 
  2545 
  2546 New in Isabelle94-6
  2547 -------------------
  2548 
  2549 * oracles -- these establish an interface between Isabelle and trusted
  2550 external reasoners, which may deliver results as theorems;
  2551 
  2552 * proof objects (in particular record all uses of oracles);
  2553 
  2554 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2555 
  2556 * "constdefs" section in theory files;
  2557 
  2558 * "primrec" section (HOL) no longer requires names;
  2559 
  2560 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2561 
  2562 
  2563 
  2564 New in Isabelle94-5
  2565 -------------------
  2566 
  2567 * reduced space requirements;
  2568 
  2569 * automatic HTML generation from theories;
  2570 
  2571 * theory files no longer require "..." (quotes) around most types;
  2572 
  2573 * new examples, including two proofs of the Church-Rosser theorem;
  2574 
  2575 * non-curried (1994) version of HOL is no longer distributed;
  2576 
  2577 
  2578 
  2579 New in Isabelle94-4
  2580 -------------------
  2581 
  2582 * greatly reduced space requirements;
  2583 
  2584 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2585 
  2586 * searchable theorem database (see the section "Retrieving theorems" on
  2587 page 8 of the Reference Manual);
  2588 
  2589 * new examples, including Grabczewski's monumental case study of the
  2590 Axiom of Choice;
  2591 
  2592 * The previous version of HOL renamed to Old_HOL;
  2593 
  2594 * The new version of HOL (previously called CHOL) uses a curried syntax
  2595 for functions.  Application looks like f a b instead of f(a,b);
  2596 
  2597 * Mutually recursive inductive definitions finally work in HOL;
  2598 
  2599 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2600 translates to the operator "split";
  2601 
  2602 
  2603 
  2604 New in Isabelle94-3
  2605 -------------------
  2606 
  2607 * new infix operator, addss, allowing the classical reasoner to
  2608 perform simplification at each step of its search.  Example:
  2609         fast_tac (cs addss ss)
  2610 
  2611 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2612 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2613 look like (a,b) instead of <a,b>;
  2614 
  2615 * PLEASE NOTE: CHOL will eventually replace HOL!
  2616 
  2617 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2618 It translates to the operator "split".  A new theory of integers is available;
  2619 
  2620 * In ZF, integer numerals now denote two's-complement binary integers.
  2621 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2622 
  2623 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2624 of the Axiom of Choice;
  2625 
  2626 
  2627 
  2628 New in Isabelle94-2
  2629 -------------------
  2630 
  2631 * Significantly faster resolution;
  2632 
  2633 * the different sections in a .thy file can now be mixed and repeated
  2634 freely;
  2635 
  2636 * Database of theorems for FOL, HOL and ZF.  New
  2637 commands including qed, qed_goal and bind_thm store theorems in the database.
  2638 
  2639 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2640 a given theory (thms_of), or find out what theory a theorem was proved in
  2641 (theory_of_thm);
  2642 
  2643 * Bugs fixed in the inductive definition and datatype packages;
  2644 
  2645 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2646 and HOL_dup_cs obsolete;
  2647 
  2648 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2649 have been removed;
  2650 
  2651 * Simpler definition of function space in ZF;
  2652 
  2653 * new results about cardinal and ordinal arithmetic in ZF;
  2654 
  2655 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2656 types;
  2657 
  2658 
  2659 $Id$