NEWS
author wenzelm
Thu Apr 22 12:19:40 2004 +0200 (2004-04-22)
changeset 14655 8a95abf87dd3
parent 14624 9b3397a848c3
child 14682 a5072752114c
permissions -rw-r--r--
Pure: considerably improved version of 'constdefs' command;
Pure: 'advanced' translation functions (parse_translation etc.);
     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 -- some existing specifications may have to
    15 be reordered.
    16 
    17 * Pure: 'advanced' translation functions (parse_translation etc.) may
    18 depend on the signature of the theory context being presently used for
    19 parsing/printing, see also isar-ref manual.
    20 
    21 
    22 
    23 New in Isabelle2004 (April 2004)
    24 --------------------------------
    25 
    26 *** General ***
    27 
    28 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
    29   Replaces linorder.ML.
    30 
    31 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
    32   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
    33   (\<a>...\<z>), are now considered normal letters, and can therefore
    34   be used anywhere where an ASCII letter (a...zA...Z) has until
    35   now. COMPATIBILITY: This obviously changes the parsing of some
    36   terms, especially where a symbol has been used as a binder, say
    37   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
    38   as an identifier.  Fix it by inserting a space around former
    39   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
    40   existing theory and ML files.
    41 
    42 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
    43 
    44 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now 
    45   allowed in identifiers. Similar to Greek letters \<^isub> is now considered 
    46   a normal (but invisible) letter. For multiple letter subscripts repeat 
    47   \<^isub> like this: x\<^isub>1\<^isub>2. 
    48 
    49 * Pure: There are now sub-/superscripts that can span more than one
    50   character. Text between \<^bsub> and \<^esub> is set in subscript in
    51   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
    52   superscript. The new control characters are not identifier parts.
    53 
    54 * Pure: Control-symbols of the form \<^raw:...> will literally print the
    55   content of "..." to the latex file instead of \isacntrl... . The "..."
    56   may consist of any printable characters excluding the end bracket >.
    57 
    58 * Pure: Using new Isar command "finalconsts" (or the ML functions
    59   Theory.add_finals or Theory.add_finals_i) it is now possible to
    60   declare constants "final", which prevents their being given a definition
    61   later.  It is useful for constants whose behaviour is fixed axiomatically
    62   rather than definitionally, such as the meta-logic connectives.
    63 
    64 * Pure: 'instance' now handles general arities with general sorts
    65   (i.e. intersections of classes),
    66 
    67 * Presentation: generated HTML now uses a CSS style sheet to make layout
    68   (somewhat) independent of content. It is copied from lib/html/isabelle.css. 
    69   It can be changed to alter the colors/layout of generated pages.
    70 
    71 
    72 *** Isar ***
    73 
    74 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
    75   cut_tac, subgoal_tac and thin_tac:
    76   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    77     locales are no longer forced to write Isar proof scripts.
    78     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    79     emulations.
    80   - INCOMPATIBILITY: names of variables to be instantiated may no
    81     longer be enclosed in quotes.  Instead, precede variable name with `?'.
    82     This is consistent with the instantiation attribute "where".
    83 
    84 * Attributes "where" and "of":
    85   - Now take type variables of instantiated theorem into account when reading
    86     the instantiation string.  This fixes a bug that caused instantiated
    87     theorems to have too special types in some circumstances.
    88   - "where" permits explicit instantiations of type variables.
    89 
    90 * Calculation commands "moreover" and "also" no longer interfere with
    91   current facts ("this"), admitting arbitrary combinations with "then"
    92   and derived forms.
    93 
    94 * Locales:
    95   - Goal statements involving the context element "includes" no longer
    96     generate theorems with internal delta predicates (those ending on
    97     "_axioms") in the premise.
    98     Resolve particular premise with <locale>.intro to obtain old form.
    99   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   100     specification and "includes" elements in goal statement.
   101   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   102     [intro?] and [elim?] (respectively) by default.
   103   - Experimental command for instantiation of locales in proof contexts:
   104         instantiate <label>[<attrs>]: <loc>
   105     Instantiates locale <loc> and adds all its theorems to the current context
   106     taking into account their attributes.  Label and attrs are optional
   107     modifiers, like in theorem declarations.  If present, names of
   108     instantiated theorems are qualified with <label>, and the attributes
   109     <attrs> are applied after any attributes these theorems might have already.
   110       If the locale has assumptions, a chained fact of the form
   111     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   112     are derived.  The command does not support old-style locales declared
   113     with "locale (open)".
   114       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   115 
   116 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   117   (Isar) contexts.
   118 
   119 
   120 *** HOL ***
   121 
   122 * Proof import: new image HOL4 contains the imported library from
   123   the HOL4 system with about 2500 theorems. It is imported by
   124   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   125   can be used like any other Isabelle image.  See
   126   HOL/Import/HOL/README for more information.
   127 
   128 * Simplifier:
   129   - Much improved handling of linear and partial orders.
   130     Reasoners for linear and partial orders are set up for type classes
   131     "linorder" and "order" respectively, and are added to the default simpset
   132     as solvers.  This means that the simplifier can build transitivity chains
   133     to solve goals from the assumptions.
   134   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   135     of blast or auto after simplification become unnecessary because the goal
   136     is solved by simplification already.
   137 
   138 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws, 
   139     all proved in axiomatic type classes for semirings, rings and fields.
   140 
   141 * Numerics:
   142   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   143     now formalized using the Ring_and_Field theory mentioned above. 
   144   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   145     than before, because now they are set up once in a generic manner.
   146   - INCOMPATIBILITY: many type-specific arithmetic laws have gone. 
   147     Look for the general versions in Ring_and_Field (and Power if they concern
   148     exponentiation).
   149 
   150 * Type "rat" of the rational numbers is now available in HOL-Complex.
   151 
   152 * Records:
   153   - Record types are now by default printed with their type abbreviation
   154     instead of the list of all field types. This can be configured via
   155     the reference "print_record_type_abbr".
   156   - Simproc "record_upd_simproc" for simplification of multiple updates added 
   157     (not enabled by default).
   158   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   159     EX x. x = sel r to True (not enabled by default).
   160   - Tactic "record_split_simp_tac" to split and simplify records added.
   161  
   162 * 'specification' command added, allowing for definition by
   163   specification.  There is also an 'ax_specification' command that
   164   introduces the new constants axiomatically.
   165 
   166 * arith(_tac) is now able to generate counterexamples for reals as well.
   167 
   168 * HOL-Algebra: new locale "ring" for non-commutative rings.
   169 
   170 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   171   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   172 
   173 * HOL-Matrix: a first theory for matrices in HOL with an application of 
   174   matrix theory to linear programming.
   175 
   176 * Unions and Intersections:
   177   The x-symbol output syntax of UN and INT has been changed
   178   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   179   i.e. the index formulae has become a subscript, like in normal math.
   180   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   181   The subscript version is also accepted as input syntax.
   182 
   183 * Unions and Intersections over Intervals:
   184   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is 
   185   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A" 
   186   like in normal math, and corresponding versions for < and for intersection.
   187 
   188 * ML: the legacy theory structures Int and List have been removed. They had
   189   conflicted with ML Basis Library structures having the same names.
   190 
   191 * 'refute' command added to search for (finite) countermodels.  Only works
   192   for a fragment of HOL.  The installation of an external SAT solver is
   193   highly recommended.  See "HOL/Refute.thy" for details.
   194 
   195 * 'quickcheck' command: Allows to find counterexamples by evaluating
   196   formulae under an assignment of free variables to random values.
   197   In contrast to 'refute', it can deal with inductive datatypes,
   198   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   199   for examples.
   200 
   201 
   202 *** HOLCF ***
   203 
   204 * Streams now come with concatenation and are part of the HOLCF image
   205 
   206 
   207 
   208 New in Isabelle2003 (May 2003)
   209 ------------------------------
   210 
   211 *** General ***
   212 
   213 * Provers/simplifier:
   214 
   215   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   216     Assumptions are now subject to complete mutual simplification,
   217     not just from left to right. The simplifier now preserves
   218     the order of assumptions.
   219 
   220     Potential INCOMPATIBILITY:
   221 
   222     -- simp sometimes diverges where the old version did
   223        not, e.g. invoking simp on the goal
   224 
   225         [| P (f x); y = x; f x = f y |] ==> Q
   226 
   227        now gives rise to the infinite reduction sequence
   228 
   229         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   230 
   231        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   232        kind of problem.
   233 
   234     -- Tactics combining classical reasoner and simplification (such as auto)
   235        are also affected by this change, because many of them rely on
   236        simp. They may sometimes diverge as well or yield a different numbers
   237        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   238        in case of problems. Sometimes subsequent calls to the classical
   239        reasoner will fail because a preceeding call to the simplifier too
   240        eagerly simplified the goal, e.g. deleted redundant premises.
   241 
   242   - The simplifier trace now shows the names of the applied rewrite rules
   243 
   244   - You can limit the number of recursive invocations of the simplifier
   245     during conditional rewriting (where the simplifie tries to solve the
   246     conditions before applying the rewrite rule):
   247     ML "simp_depth_limit := n"
   248     where n is an integer. Thus you can force termination where previously
   249     the simplifier would diverge.
   250 
   251   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   252 
   253   - No longer aborts on failed congruence proof.  Instead, the
   254     congruence is ignored.
   255 
   256 * Pure: New generic framework for extracting programs from constructive
   257   proofs. See HOL/Extraction.thy for an example instantiation, as well
   258   as HOL/Extraction for some case studies.
   259 
   260 * Pure: The main goal of the proof state is no longer shown by default, only
   261 the subgoals. This behaviour is controlled by a new flag.
   262    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   263 (ML: Proof.show_main_goal).
   264 
   265 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   266 rules whose conclusion matches subgoal 1:
   267       PG menu: Isabelle/Isar -> Show me -> matching rules
   268 The rules are ordered by how closely they match the subgoal.
   269 In particular, rules that solve a subgoal outright are displayed first
   270 (or rather last, the way they are printed).
   271 (ML: ProofGeneral.print_intros())
   272 
   273 * Pure: New flag trace_unify_fail causes unification to print
   274 diagnostic information (PG: in trace buffer) when it fails. This is
   275 useful for figuring out why single step proofs like rule, erule or
   276 assumption failed.
   277 
   278 * Pure: Locale specifications now produce predicate definitions
   279 according to the body of text (covering assumptions modulo local
   280 definitions); predicate "loc_axioms" covers newly introduced text,
   281 while "loc" is cumulative wrt. all included locale expressions; the
   282 latter view is presented only on export into the global theory
   283 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   284 on the old view without predicates;
   285 
   286 * Pure: predefined locales "var" and "struct" are useful for sharing
   287 parameters (as in CASL, for example); just specify something like
   288 ``var x + var y + struct M'' as import;
   289 
   290 * Pure: improved thms_containing: proper indexing of facts instead of
   291 raw theorems; check validity of results wrt. current name space;
   292 include local facts of proof configuration (also covers active
   293 locales), cover fixed variables in index; may use "_" in term
   294 specification; an optional limit for the number of printed facts may
   295 be given (the default is 40);
   296 
   297 * Pure: disallow duplicate fact bindings within new-style theory files
   298 (batch-mode only);
   299 
   300 * Provers: improved induct method: assumptions introduced by case
   301 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   302 the goal statement); "foo" still refers to all facts collectively;
   303 
   304 * Provers: the function blast.overloaded has been removed: all constants
   305 are regarded as potentially overloaded, which improves robustness in exchange
   306 for slight decrease in efficiency;
   307 
   308 * Provers/linorder: New generic prover for transitivity reasoning over
   309 linear orders.  Note: this prover is not efficient!
   310 
   311 * Isar: preview of problems to finish 'show' now produce an error
   312 rather than just a warning (in interactive mode);
   313 
   314 
   315 *** HOL ***
   316 
   317 * arith(_tac)
   318 
   319  - Produces a counter example if it cannot prove a goal.
   320    Note that the counter example may be spurious if the goal is not a formula
   321    of quantifier-free linear arithmetic.
   322    In ProofGeneral the counter example appears in the trace buffer.
   323 
   324  - Knows about div k and mod k where k is a numeral of type nat or int.
   325 
   326  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   327    linear arithmetic fails. This takes account of quantifiers and divisibility.
   328    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   329 
   330 * simp's arithmetic capabilities have been enhanced a bit: it now
   331 takes ~= in premises into account (by performing a case split);
   332 
   333 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   334 are distributed over a sum of terms;
   335 
   336 * New tactic "trans_tac" and method "trans" instantiate
   337 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   338 "<=", "<" and "="). 
   339 
   340 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   341 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   342 
   343 * 'typedef' command has new option "open" to suppress the set
   344 definition;
   345 
   346 * functions Min and Max on finite sets have been introduced (theory
   347 Finite_Set);
   348 
   349 * attribute [symmetric] now works for relations as well; it turns
   350 (x,y) : R^-1 into (y,x) : R, and vice versa;
   351 
   352 * induct over a !!-quantified statement (say !!x1..xn):
   353   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   354 
   355 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   356 %x. None. Warning: empty_def now refers to the previously hidden definition
   357 of the empty set.
   358 
   359 * Algebra: formalization of classical algebra.  Intended as base for
   360 any algebraic development in Isabelle.  Currently covers group theory
   361 (up to Sylow's theorem) and ring theory (Universal Property of
   362 Univariate Polynomials).  Contributions welcome;
   363 
   364 * GroupTheory: deleted, since its material has been moved to Algebra;
   365 
   366 * Complex: new directory of the complex numbers with numeric constants, 
   367 nonstandard complex numbers, and some complex analysis, standard and 
   368 nonstandard (Jacques Fleuriot);
   369 
   370 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   371 
   372 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   373 Fleuriot);
   374 
   375 * Real/HahnBanach: updated and adapted to locales;
   376 
   377 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   378 Gray and Kramer);
   379 
   380 * UNITY: added the Meier-Sanders theory of progress sets;
   381 
   382 * MicroJava: bytecode verifier and lightweight bytecode verifier
   383 as abstract algorithms, instantiated to the JVM;
   384 
   385 * Bali: Java source language formalization. Type system, operational
   386 semantics, axiomatic semantics. Supported language features:
   387 classes, interfaces, objects,virtual methods, static methods,
   388 static/instance fields, arrays, access modifiers, definite
   389 assignment, exceptions.
   390 
   391 
   392 *** ZF ***
   393 
   394 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   395 universe, etc.);
   396 
   397 * Main ZF: virtually all theories converted to new-style format;
   398 
   399 
   400 *** ML ***
   401 
   402 * Pure: Tactic.prove provides sane interface for internal proofs;
   403 omits the infamous "standard" operation, so this is more appropriate
   404 than prove_goalw_cterm in many situations (e.g. in simprocs);
   405 
   406 * Pure: improved error reporting of simprocs;
   407 
   408 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   409 up simprocs;
   410 
   411 
   412 *** Document preparation ***
   413 
   414 * uses \par instead of \\ for line breaks in theory text. This may
   415 shift some page breaks in large documents. To get the old behaviour
   416 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   417 
   418 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   419 other packages
   420 
   421 * \<euro> now needs package babel/greek instead of marvosym (which
   422 broke \Rightarrow)
   423 
   424 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   425 textcomp package)
   426 
   427 
   428 
   429 New in Isabelle2002 (March 2002)
   430 --------------------------------
   431 
   432 *** Document preparation ***
   433 
   434 * greatly simplified document preparation setup, including more
   435 graceful interpretation of isatool usedir -i/-d/-D options, and more
   436 instructive isatool mkdir; users should basically be able to get
   437 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   438 users may run a separate document processing stage manually like this:
   439 "isatool usedir -D output HOL Test && isatool document Test/output";
   440 
   441 * theory dependency graph may now be incorporated into documents;
   442 isatool usedir -g true will produce session_graph.eps/.pdf for use
   443 with \includegraphics of LaTeX;
   444 
   445 * proper spacing of consecutive markup elements, especially text
   446 blocks after section headings;
   447 
   448 * support bold style (for single symbols only), input syntax is like
   449 this: "\<^bold>\<alpha>" or "\<^bold>A";
   450 
   451 * \<bullet> is now output as bold \cdot by default, which looks much
   452 better in printed text;
   453 
   454 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   455 note that these symbols are currently unavailable in Proof General /
   456 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   457 
   458 * isatool latex no longer depends on changed TEXINPUTS, instead
   459 isatool document copies the Isabelle style files to the target
   460 location;
   461 
   462 
   463 *** Isar ***
   464 
   465 * Pure/Provers: improved proof by cases and induction;
   466   - 'case' command admits impromptu naming of parameters (such as
   467     "case (Suc n)");
   468   - 'induct' method divinates rule instantiation from the inductive
   469     claim; no longer requires excessive ?P bindings for proper
   470     instantiation of cases;
   471   - 'induct' method properly enumerates all possibilities of set/type
   472     rules; as a consequence facts may be also passed through *type*
   473     rules without further ado;
   474   - 'induct' method now derives symbolic cases from the *rulified*
   475     rule (before it used to rulify cases stemming from the internal
   476     atomized version); this means that the context of a non-atomic
   477     statement becomes is included in the hypothesis, avoiding the
   478     slightly cumbersome show "PROP ?case" form;
   479   - 'induct' may now use elim-style induction rules without chaining
   480     facts, using ``missing'' premises from the goal state; this allows
   481     rules stemming from inductive sets to be applied in unstructured
   482     scripts, while still benefitting from proper handling of non-atomic
   483     statements; NB: major inductive premises need to be put first, all
   484     the rest of the goal is passed through the induction;
   485   - 'induct' proper support for mutual induction involving non-atomic
   486     rule statements (uses the new concept of simultaneous goals, see
   487     below);
   488   - append all possible rule selections, but only use the first
   489     success (no backtracking);
   490   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   491   - undeclared rule case names default to numbers 1, 2, 3, ...;
   492   - added 'print_induct_rules' (covered by help item in recent Proof
   493     General versions);
   494   - moved induct/cases attributes to Pure, methods to Provers;
   495   - generic method setup instantiated for FOL and HOL;
   496 
   497 * Pure: support multiple simultaneous goal statements, for example
   498 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   499 meta-level mechanism, this acts as if several individual goals had
   500 been stated separately; in particular common proof methods need to be
   501 repeated in order to cover all claims; note that a single elimination
   502 step is *not* sufficient to establish the two conjunctions, so this
   503 fails:
   504 
   505   assume "A & B" then have A and B ..   (*".." fails*)
   506 
   507 better use "obtain" in situations as above; alternative refer to
   508 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   509 
   510 * Pure: proper integration with ``locales''; unlike the original
   511 version by Florian Kammüller, Isar locales package high-level proof
   512 contexts rather than raw logical ones (e.g. we admit to include
   513 attributes everywhere); operations on locales include merge and
   514 rename; support for implicit arguments (``structures''); simultaneous
   515 type-inference over imports and text; see also HOL/ex/Locales.thy for
   516 some examples;
   517 
   518 * Pure: the following commands have been ``localized'', supporting a
   519 target locale specification "(in name)": 'lemma', 'theorem',
   520 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   521 stored both within the locale and at the theory level (exported and
   522 qualified by the locale name);
   523 
   524 * Pure: theory goals may now be specified in ``long'' form, with
   525 ad-hoc contexts consisting of arbitrary locale elements. for example
   526 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   527 definitions may be given, too); the result is a meta-level rule with
   528 the context elements being discharged in the obvious way;
   529 
   530 * Pure: new proof command 'using' allows to augment currently used
   531 facts after a goal statement ('using' is syntactically analogous to
   532 'apply', but acts on the goal's facts only); this allows chained facts
   533 to be separated into parts given before and after a claim, as in
   534 ``from a and b have C using d and e <proof>'';
   535 
   536 * Pure: renamed "antecedent" case to "rule_context";
   537 
   538 * Pure: new 'judgment' command records explicit information about the
   539 object-logic embedding (used by several tools internally); no longer
   540 use hard-wired "Trueprop";
   541 
   542 * Pure: added 'corollary' command;
   543 
   544 * Pure: fixed 'token_translation' command;
   545 
   546 * Pure: removed obsolete 'exported' attribute;
   547 
   548 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   549 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   550 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   551 
   552 * Pure: method 'atomize' presents local goal premises as object-level
   553 statements (atomic meta-level propositions); setup controlled via
   554 rewrite rules declarations of 'atomize' attribute; example
   555 application: 'induct' method with proper rule statements in improper
   556 proof *scripts*;
   557 
   558 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   559 now consider the syntactic context of assumptions, giving a better
   560 chance to get type-inference of the arguments right (this is
   561 especially important for locales);
   562 
   563 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   564 mode;
   565 
   566 * Pure/obtain: the formal conclusion "thesis", being marked as
   567 ``internal'', may no longer be reference directly in the text;
   568 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   569 situations;
   570 
   571 * Pure: generic 'sym' attribute which declares a rule both as pure
   572 'elim?' and for the 'symmetric' operation;
   573 
   574 * Pure: marginal comments ``--'' may now occur just anywhere in the
   575 text; the fixed correlation with particular command syntax has been
   576 discontinued;
   577 
   578 * Pure: new method 'rules' is particularly well-suited for proof
   579 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   580 but often produces more compact proof terms with less detours;
   581 
   582 * Pure/Provers/classical: simplified integration with pure rule
   583 attributes and methods; the classical "intro?/elim?/dest?"
   584 declarations coincide with the pure ones; the "rule" method no longer
   585 includes classically swapped intros; "intro" and "elim" methods no
   586 longer pick rules from the context; also got rid of ML declarations
   587 AddXIs/AddXEs/AddXDs; all of this has some potential for
   588 INCOMPATIBILITY;
   589 
   590 * Provers/classical: attribute 'swapped' produces classical inversions
   591 of introduction rules;
   592 
   593 * Provers/simplifier: 'simplified' attribute may refer to explicit
   594 rules instead of full simplifier context; 'iff' attribute handles
   595 conditional rules;
   596 
   597 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   598 
   599 * HOL: 'recdef' now fails on unfinished automated proofs, use
   600 "(permissive)" option to recover old behavior;
   601 
   602 * HOL: 'inductive' no longer features separate (collective) attributes
   603 for 'intros' (was found too confusing);
   604 
   605 * HOL: properly declared induction rules less_induct and
   606 wf_induct_rule;
   607 
   608 
   609 *** HOL ***
   610 
   611 * HOL: moved over to sane numeral syntax; the new policy is as
   612 follows:
   613 
   614   - 0 and 1 are polymorphic constants, which are defined on any
   615   numeric type (nat, int, real etc.);
   616 
   617   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   618   binary representation internally;
   619 
   620   - type nat has special constructor Suc, and generally prefers Suc 0
   621   over 1::nat and Suc (Suc 0) over 2::nat;
   622 
   623 This change may cause significant problems of INCOMPATIBILITY; here
   624 are some hints on converting existing sources:
   625 
   626   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   627   entities, so expressions involving "-" (unary or binary minus) need
   628   to be spaced properly;
   629 
   630   - existing occurrences of "1" may need to be constraint "1::nat" or
   631   even replaced by Suc 0; similar for old "2";
   632 
   633   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   634 
   635   - remove all special provisions on numerals in proofs;
   636 
   637 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   638 representation (depends on bin_arith_simps in the default context);
   639 
   640 * HOL: symbolic syntax for x^2 (numeral 2);
   641 
   642 * HOL: the class of all HOL types is now called "type" rather than
   643 "term"; INCOMPATIBILITY, need to adapt references to this type class
   644 in axclass/classes, instance/arities, and (usually rare) occurrences
   645 in typings (of consts etc.); internally the class is called
   646 "HOL.type", ML programs should refer to HOLogic.typeS;
   647 
   648 * HOL/record package improvements:
   649   - new derived operations "fields" to build a partial record section,
   650     "extend" to promote a fixed record to a record scheme, and
   651     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   652     declared as simp by default;
   653   - shared operations ("more", "fields", etc.) now need to be always
   654     qualified) --- potential INCOMPATIBILITY;
   655   - removed "make_scheme" operations (use "make" with "extend") --
   656     INCOMPATIBILITY;
   657   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   658   - provides cases/induct rules for use with corresponding Isar
   659     methods (for concrete records, record schemes, concrete more
   660     parts, and schematic more parts -- in that order);
   661   - internal definitions directly based on a light-weight abstract
   662     theory of product types over typedef rather than datatype;
   663 
   664 * HOL: generic code generator for generating executable ML code from
   665 specifications; specific support for HOL constructs such as inductive
   666 datatypes and sets, as well as recursive functions; can be invoked
   667 via 'generate_code' theory section;
   668 
   669 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   670 
   671 * HOL: consolidated and renamed several theories.  In particular:
   672 	Ord.thy has been absorbed into HOL.thy
   673 	String.thy has been absorbed into List.thy
   674  
   675 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   676 (beware of argument permutation!);
   677 
   678 * HOL: linorder_less_split superseded by linorder_cases;
   679 
   680 * HOL/List: "nodups" renamed to "distinct";
   681 
   682 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   683 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   684   - Ex_def has changed, now need to use some_eq_ex
   685 
   686 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   687 in this (rare) case use:
   688 
   689   delSWrapper "split_all_tac"
   690   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   691 
   692 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   693 MAY FAIL;
   694 
   695 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   696 Isabelle's type classes, ^ on functions and relations has too general
   697 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   698 necessary to attach explicit type constraints;
   699 
   700 * HOL/Relation: the prefix name of the infix "O" has been changed from
   701 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   702 renamed accordingly (eg "compI" -> "rel_compI").
   703 
   704 * HOL: syntax translations now work properly with numerals and records
   705 expressions;
   706 
   707 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   708 of "lam" -- INCOMPATIBILITY;
   709 
   710 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   711 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   712 renamed "Product_Type.unit";
   713 
   714 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   715 
   716 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   717 the "cases" method);
   718 
   719 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   720 Florian Kammüller);
   721 
   722 * HOL/IMP: updated and converted to new-style theory format; several
   723 parts turned into readable document, with proper Isar proof texts and
   724 some explanations (by Gerwin Klein);
   725 
   726 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   727 
   728 * HOL-Hyperreal is now a logic image;
   729 
   730 
   731 *** HOLCF ***
   732 
   733 * Isar: consts/constdefs supports mixfix syntax for continuous
   734 operations;
   735 
   736 * Isar: domain package adapted to new-style theory format, e.g. see
   737 HOLCF/ex/Dnat.thy;
   738 
   739 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   740 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   741 lift.induct_tac, always use UU instead of Undef;
   742 
   743 * HOLCF/IMP: updated and converted to new-style theory;
   744 
   745 
   746 *** ZF ***
   747 
   748 * Isar: proper integration of logic-specific tools and packages,
   749 including theory commands '(co)inductive', '(co)datatype',
   750 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   751 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   752 
   753 * theory Main no longer includes AC; for the Axiom of Choice, base
   754 your theory on Main_ZFC;
   755 
   756 * the integer library now covers quotients and remainders, with many
   757 laws relating division to addition, multiplication, etc.;
   758 
   759 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   760 typeless version of the formalism;
   761 
   762 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   763 format;
   764 
   765 * ZF/Induct: new directory for examples of inductive definitions,
   766 including theory Multiset for multiset orderings; converted to
   767 new-style theory format;
   768 
   769 * ZF: many new theorems about lists, ordinals, etc.;
   770 
   771 
   772 *** General ***
   773 
   774 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   775 variable proof controls level of detail: 0 = no proofs (only oracle
   776 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   777 also ref manual for further ML interfaces;
   778 
   779 * Pure/axclass: removed obsolete ML interface
   780 goal_subclass/goal_arity;
   781 
   782 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   783 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   784 separate tokens, so expressions involving minus need to be spaced
   785 properly;
   786 
   787 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   788 rather than "infixl" or "infixr";
   789 
   790 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   791 sort constraint specifications in type inference; e.g. "x::_::foo"
   792 ensures that the type of "x" is of sort "foo" (but not necessarily a
   793 type variable);
   794 
   795 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   796 control output of nested => (types); the default behavior is
   797 "type_brackets";
   798 
   799 * Pure/syntax: builtin parse translation for "_constify" turns valued
   800 tokens into AST constants;
   801 
   802 * Pure/syntax: prefer later declarations of translations and print
   803 translation functions; potential INCOMPATIBILITY: need to reverse
   804 multiple declarations for same syntax element constant;
   805 
   806 * Pure/show_hyps reset by default (in accordance to existing Isar
   807 practice);
   808 
   809 * Provers/classical: renamed addaltern to addafter, addSaltern to
   810 addSafter;
   811 
   812 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   813 as well;
   814 
   815 * system: tested support for MacOS X; should be able to get Isabelle +
   816 Proof General to work in a plain Terminal after installing Poly/ML
   817 (e.g. from the Isabelle distribution area) and GNU bash alone
   818 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   819 support requires further installations, e.g. from
   820 http://fink.sourceforge.net/);
   821 
   822 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   823 
   824 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   825 of 40 MB), cf. ML_OPTIONS;
   826 
   827 * system: Proof General keywords specification is now part of the
   828 Isabelle distribution (see etc/isar-keywords.el);
   829 
   830 * system: support for persistent Proof General sessions (refrain from
   831 outdating all loaded theories on startup); user may create writable
   832 logic images like this: ``isabelle -q HOL Test'';
   833 
   834 * system: smart selection of Isabelle process versus Isabelle
   835 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   836 run both "isabelle" and "Isabelle" even if file names are badly
   837 damaged (executable inspects the case of the first letter of its own
   838 name); added separate "isabelle-process" and "isabelle-interface";
   839 
   840 * system: refrain from any attempt at filtering input streams; no
   841 longer support ``8bit'' encoding of old isabelle font, instead proper
   842 iso-latin characters may now be used; the related isatools
   843 "symbolinput" and "nonascii" have disappeared as well;
   844 
   845 * system: removed old "xterm" interface (the print modes "xterm" and
   846 "xterm_color" are still available for direct use in a suitable
   847 terminal);
   848 
   849 
   850 
   851 New in Isabelle99-2 (February 2001)
   852 -----------------------------------
   853 
   854 *** Overview of INCOMPATIBILITIES ***
   855 
   856 * HOL: please note that theories in the Library and elsewhere often use the
   857 new-style (Isar) format; to refer to their theorems in an ML script you must
   858 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   859 
   860 * HOL: inductive package no longer splits induction rule aggressively,
   861 but only as far as specified by the introductions given; the old
   862 format may be recovered via ML function complete_split_rule or attribute
   863 'split_rule (complete)';
   864 
   865 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   866 gfp_Tarski to gfp_unfold;
   867 
   868 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   869 
   870 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   871 relation); infix "^^" has been renamed "``"; infix "``" has been
   872 renamed "`"; "univalent" has been renamed "single_valued";
   873 
   874 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   875 operation;
   876 
   877 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   878 
   879 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   880 
   881 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   882 consequence, it is no longer monotonic wrt. the local goal context
   883 (which is now passed through the inductive cases);
   884 
   885 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   886 \<gg> to \<ggreater>;
   887 
   888 
   889 *** Document preparation ***
   890 
   891 * \isabellestyle{NAME} selects version of Isabelle output (currently
   892 available: are "it" for near math-mode best-style output, "sl" for
   893 slanted text style, and "tt" for plain type-writer; if no
   894 \isabellestyle command is given, output is according to slanted
   895 type-writer);
   896 
   897 * support sub/super scripts (for single symbols only), input syntax is
   898 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   899 
   900 * some more standard symbols; see Appendix A of the system manual for
   901 the complete list of symbols defined in isabellesym.sty;
   902 
   903 * improved isabelle style files; more abstract symbol implementation
   904 (should now use \isamath{...} and \isatext{...} in custom symbol
   905 definitions);
   906 
   907 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   908 state; Note that presentation of goal states does not conform to
   909 actual human-readable proof documents.  Please do not include goal
   910 states into document output unless you really know what you are doing!
   911 
   912 * proper indentation of antiquoted output with proportional LaTeX
   913 fonts;
   914 
   915 * no_document ML operator temporarily disables LaTeX document
   916 generation;
   917 
   918 * isatool unsymbolize tunes sources for plain ASCII communication;
   919 
   920 
   921 *** Isar ***
   922 
   923 * Pure: Isar now suffers initial goal statements to contain unbound
   924 schematic variables (this does not conform to actual readable proof
   925 documents, due to unpredictable outcome and non-compositional proof
   926 checking); users who know what they are doing may use schematic goals
   927 for Prolog-style synthesis of proven results;
   928 
   929 * Pure: assumption method (an implicit finishing) now handles actual
   930 rules as well;
   931 
   932 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   933 initial goal, declare "that" only as Pure intro (only for single
   934 steps); the "that" rule assumption may now be involved in implicit
   935 finishing, thus ".." becomes a feasible for trivial obtains;
   936 
   937 * Pure: default proof step now includes 'intro_classes'; thus trivial
   938 instance proofs may be performed by "..";
   939 
   940 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   941 statements as well;
   942 
   943 * Pure: more robust selection of calculational rules;
   944 
   945 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   946 rule (as well as the assumption rule);
   947 
   948 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   949 lemmas, using the graph browser tool;
   950 
   951 * Pure: predict failure of "show" in interactive mode;
   952 
   953 * Pure: 'thms_containing' now takes actual terms as arguments;
   954 
   955 * HOL: improved method 'induct' --- now handles non-atomic goals
   956 (potential INCOMPATIBILITY); tuned error handling;
   957 
   958 * HOL: cases and induct rules now provide explicit hints about the
   959 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   960 any remaining facts are inserted into the goal verbatim;
   961 
   962 * HOL: local contexts (aka cases) may now contain term bindings as
   963 well; the 'cases' and 'induct' methods new provide a ?case binding for
   964 the result to be shown in each case;
   965 
   966 * HOL: added 'recdef_tc' command;
   967 
   968 * isatool convert assists in eliminating legacy ML scripts;
   969 
   970 
   971 *** HOL ***
   972 
   973 * HOL/Library: a collection of generic theories to be used together
   974 with main HOL; the theory loader path already includes this directory
   975 by default; the following existing theories have been moved here:
   976 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   977 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   978 
   979 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   980 modelling and verification task performed in Isabelle/HOL +
   981 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   982 
   983 * HOL/Algebra: special summation operator SUM no longer exists, it has
   984 been replaced by setsum; infix 'assoc' now has priority 50 (like
   985 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   986 'domain', this makes the theory consistent with mathematical
   987 literature;
   988 
   989 * HOL basics: added overloaded operations "inverse" and "divide"
   990 (infix "/"), syntax for generic "abs" operation, generic summation
   991 operator \<Sum>;
   992 
   993 * HOL/typedef: simplified package, provide more useful rules (see also
   994 HOL/subset.thy);
   995 
   996 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   997 now expressed as a proper nested rule (old-style tactic scripts may
   998 require atomize_strip_tac to cope with non-atomic premises);
   999 
  1000 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1001 to "split_conv" (old name still available for compatibility);
  1002 
  1003 * HOL: improved concrete syntax for strings (e.g. allows translation
  1004 rules with string literals);
  1005 
  1006 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1007  and Fleuriot's mechanization of analysis, including the transcendental
  1008  functions for the reals;
  1009 
  1010 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1011 
  1012 
  1013 *** CTT ***
  1014 
  1015 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1016 "lam" is displayed as TWO lambda-symbols
  1017 
  1018 * CTT: theory Main now available, containing everything (that is, Bool
  1019 and Arith);
  1020 
  1021 
  1022 *** General ***
  1023 
  1024 * Pure: the Simplifier has been implemented properly as a derived rule
  1025 outside of the actual kernel (at last!); the overall performance
  1026 penalty in practical applications is about 50%, while reliability of
  1027 the Isabelle inference kernel has been greatly improved;
  1028 
  1029 * print modes "brackets" and "no_brackets" control output of nested =>
  1030 (types) and ==> (props); the default behaviour is "brackets";
  1031 
  1032 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1033 as assumptions as well;
  1034 
  1035 * system: support Poly/ML 4.0;
  1036 
  1037 * system: isatool install handles KDE version 1 or 2;
  1038 
  1039 
  1040 
  1041 New in Isabelle99-1 (October 2000)
  1042 ----------------------------------
  1043 
  1044 *** Overview of INCOMPATIBILITIES ***
  1045 
  1046 * HOL: simplification of natural numbers is much changed; to partly
  1047 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1048 issue the following ML commands:
  1049 
  1050   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1051   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1052 
  1053 * HOL: simplification no longer dives into case-expressions; this is
  1054 controlled by "t.weak_case_cong" for each datatype t;
  1055 
  1056 * HOL: nat_less_induct renamed to less_induct;
  1057 
  1058 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1059 fixsome to patch .thy and .ML sources automatically;
  1060 
  1061   select_equality  -> some_equality
  1062   select_eq_Ex     -> some_eq_ex
  1063   selectI2EX       -> someI2_ex
  1064   selectI2         -> someI2
  1065   selectI          -> someI
  1066   select1_equality -> some1_equality
  1067   Eps_sym_eq       -> some_sym_eq_trivial
  1068   Eps_eq           -> some_eq_trivial
  1069 
  1070 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1071 
  1072 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1073 instead);
  1074 
  1075 * HOL: the recursion equations generated by 'recdef' are now called
  1076 f.simps instead of f.rules;
  1077 
  1078 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1079 
  1080 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1081 sometimes be needed;
  1082 
  1083 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1084 
  1085 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1086 
  1087 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1088 product is now "<*>" instead of "Times"; the lexicographic product is
  1089 now "<*lex*>" instead of "**";
  1090 
  1091 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1092 of main HOL, but was unused); better use HOL's datatype package;
  1093 
  1094 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1095 the old syntax may be recovered as follows:
  1096 
  1097   syntax (symbols)
  1098     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1099       (infixl "\\<oplus>" 100)
  1100 
  1101 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1102 
  1103 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1104 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1105 internally;
  1106 
  1107 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1108 changed from A/r to A//r;
  1109 
  1110 * ZF: new treatment of arithmetic (nat & int) may break some old
  1111 proofs;
  1112 
  1113 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1114 rulify -> rule_format, elimify -> elim_format, ...);
  1115 
  1116 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1117 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1118 should have to change intro!! to intro? only); replaced "delrule" by
  1119 "rule del";
  1120 
  1121 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1122 
  1123 * Provers: strengthened force_tac by using new first_best_tac;
  1124 
  1125 * LaTeX document preparation: several changes of isabelle.sty (see
  1126 lib/texinputs);
  1127 
  1128 
  1129 *** Document preparation ***
  1130 
  1131 * formal comments (text blocks etc.) in new-style theories may now
  1132 contain antiquotations of thm/prop/term/typ/text to be presented
  1133 according to latex print mode; concrete syntax is like this:
  1134 @{term[show_types] "f(x) = a + x"};
  1135 
  1136 * isatool mkdir provides easy setup of Isabelle session directories,
  1137 including proper document sources;
  1138 
  1139 * generated LaTeX sources are now deleted after successful run
  1140 (isatool document -c); may retain a copy somewhere else via -D option
  1141 of isatool usedir;
  1142 
  1143 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1144 style files, achieving self-contained LaTeX sources and simplifying
  1145 LaTeX debugging;
  1146 
  1147 * old-style theories now produce (crude) LaTeX output as well;
  1148 
  1149 * browser info session directories are now self-contained (may be put
  1150 on WWW server seperately); improved graphs of nested sessions; removed
  1151 graph for 'all sessions';
  1152 
  1153 * several improvements in isabelle style files; \isabellestyle{it}
  1154 produces fake math mode output; \isamarkupheader is now \section by
  1155 default; see lib/texinputs/isabelle.sty etc.;
  1156 
  1157 
  1158 *** Isar ***
  1159 
  1160 * Isar/Pure: local results and corresponding term bindings are now
  1161 subject to Hindley-Milner polymorphism (similar to ML); this
  1162 accommodates incremental type-inference very nicely;
  1163 
  1164 * Isar/Pure: new derived language element 'obtain' supports
  1165 generalized existence reasoning;
  1166 
  1167 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1168 support accumulation of results, without applying any rules yet;
  1169 useful to collect intermediate results without explicit name
  1170 references, and for use with transitivity rules with more than 2
  1171 premises;
  1172 
  1173 * Isar/Pure: scalable support for case-analysis type proofs: new
  1174 'case' language element refers to local contexts symbolically, as
  1175 produced by certain proof methods; internally, case names are attached
  1176 to theorems as "tags";
  1177 
  1178 * Isar/Pure: theory command 'hide' removes declarations from
  1179 class/type/const name spaces;
  1180 
  1181 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1182 indicate potential overloading;
  1183 
  1184 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1185 
  1186 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1187 "{a,b,c}" instead of {a,b,c};
  1188 
  1189 * Isar/Pure now provides its own version of intro/elim/dest
  1190 attributes; useful for building new logics, but beware of confusion
  1191 with the version in Provers/classical;
  1192 
  1193 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1194 case name 'antecedent';
  1195 
  1196 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1197 to the current context is now done automatically);
  1198 
  1199 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1200 for definining proof methods in ML;
  1201 
  1202 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1203 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1204 most cases, one should have to change intro!! to intro? only);
  1205 replaced "delrule" by "rule del";
  1206 
  1207 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1208 'symmetric' attribute (the latter supercedes [RS sym]);
  1209 
  1210 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1211 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1212 well (including splits);
  1213 
  1214 * Isar/Provers: Simplifier and Classical methods now support all kind
  1215 of modifiers used in the past, including 'cong', 'iff', etc.
  1216 
  1217 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1218 of Simplifier and Classical reasoner);
  1219 
  1220 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1221 now support named cases; major packages (inductive, datatype, primrec,
  1222 recdef) support case names and properly name parameters;
  1223 
  1224 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1225 monotonicity conditions are extracted to be proven at end of
  1226 calculations;
  1227 
  1228 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1229 method anyway;
  1230 
  1231 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1232 split_if split_if_asm; datatype package provides theorems foo.splits =
  1233 foo.split foo.split_asm for each datatype;
  1234 
  1235 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1236 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1237 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1238 use "(cases (simplified))" method in proper proof texts);
  1239 
  1240 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1241 
  1242 * Isar: names of theorems etc. may be natural numbers as well;
  1243 
  1244 * Isar: 'pr' command: optional arguments for goals_limit and
  1245 ProofContext.prems_limit; no longer prints theory contexts, but only
  1246 proof states;
  1247 
  1248 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1249 additional print modes to be specified; e.g. "pr(latex)" will print
  1250 proof state according to the Isabelle LaTeX style;
  1251 
  1252 * Isar: improved support for emulating tactic scripts, including proof
  1253 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1254 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1255 (for HOL datatypes);
  1256 
  1257 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1258 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1259 'proof method scripts' have to be in depth-first order;
  1260 
  1261 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1262 
  1263 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1264 should instead use individual commands for printing items
  1265 (print_commands, print_methods etc.);
  1266 
  1267 * Isar: added 'nothing' --- the empty list of theorems;
  1268 
  1269 
  1270 *** HOL ***
  1271 
  1272 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1273 corresponding virtual machine and a specification of its bytecode
  1274 verifier and a lightweight bytecode verifier, including proofs of
  1275 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1276 Cornelia Pusch (see also the homepage of project Bali at
  1277 http://isabelle.in.tum.de/Bali/);
  1278 
  1279 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1280 Clemens Ballarin;
  1281 
  1282 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1283 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1284 Rasmussen;
  1285 
  1286 * HOL/Lattice: fundamental concepts of lattice theory and order
  1287 structures, including duals, properties of bounds versus algebraic
  1288 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1289 Theorem for complete lattices etc.; may also serve as a demonstration
  1290 for abstract algebraic reasoning using axiomatic type classes, and
  1291 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1292 
  1293 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1294 von Oheimb;
  1295 
  1296 * HOL/IMPP: extension of IMP with local variables and mutually
  1297 recursive procedures, by David von Oheimb;
  1298 
  1299 * HOL/Lambda: converted into new-style theory and document;
  1300 
  1301 * HOL/ex/Multiquote: example of multiple nested quotations and
  1302 anti-quotations -- basically a generalized version of de-Bruijn
  1303 representation; very useful in avoiding lifting of operations;
  1304 
  1305 * HOL/record: added general record equality rule to simpset; fixed
  1306 select-update simplification procedure to handle extended records as
  1307 well; admit "r" as field name;
  1308 
  1309 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1310 other numeric types and also as the identity of groups, rings, etc.;
  1311 
  1312 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1313 Types nat and int belong to this axclass;
  1314 
  1315 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1316    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1317    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1318   two terms #m*u and #n*u are replaced by #(m+n)*u
  1319     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1320   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1321     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1322 
  1323 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1324 powerful prover for predicate logic but knows nothing of clasets; see
  1325 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1326 
  1327 * HOL: new version of "case_tac" subsumes both boolean case split and
  1328 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1329 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1330 
  1331 * HOL: simplification no longer dives into case-expressions: only the
  1332 selector expression is simplified, but not the remaining arms; to
  1333 enable full simplification of case-expressions for datatype t, you may
  1334 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1335 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1336 
  1337 * HOL/recdef: the recursion equations generated by 'recdef' for
  1338 function 'f' are now called f.simps instead of f.rules; if all
  1339 termination conditions are proved automatically, these simplification
  1340 rules are added to the simpset, as in primrec; rules may be named
  1341 individually as well, resulting in a separate list of theorems for
  1342 each equation;
  1343 
  1344 * HOL/While is a new theory that provides a while-combinator. It
  1345 permits the definition of tail-recursive functions without the
  1346 provision of a termination measure. The latter is necessary once the
  1347 invariant proof rule for while is applied.
  1348 
  1349 * HOL: new (overloaded) notation for the set of elements below/above
  1350 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1351 
  1352 * HOL: theorems impI, allI, ballI bound as "strip";
  1353 
  1354 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1355 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1356 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1357 
  1358 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1359 
  1360 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1361 main HOL, but was unused);
  1362 
  1363 * HOL: fewer consts declared as global (e.g. have to refer to
  1364 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1365 
  1366 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1367 in case of overlap with user translations (e.g. judgements over
  1368 tuples); (note that the underlying logical represenation is still
  1369 bogus);
  1370 
  1371 
  1372 *** ZF ***
  1373 
  1374 * ZF: simplification automatically cancels common terms in arithmetic
  1375 expressions over nat and int;
  1376 
  1377 * ZF: new treatment of nat to minimize type-checking: all operators
  1378 coerce their operands to a natural number using the function natify,
  1379 making the algebraic laws unconditional;
  1380 
  1381 * ZF: as above, for int: operators coerce their operands to an integer
  1382 using the function intify;
  1383 
  1384 * ZF: the integer library now contains many of the usual laws for the
  1385 orderings, including $<=, and monotonicity laws for $+ and $*;
  1386 
  1387 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1388 simplification;
  1389 
  1390 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1391 to the simplifier and classical reasoner simultaneously;
  1392 
  1393 
  1394 *** General ***
  1395 
  1396 * Provers: blast_tac now handles actual object-logic rules as
  1397 assumptions; note that auto_tac uses blast_tac internally as well;
  1398 
  1399 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1400 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1401 
  1402 * Provers: delrules now handles destruct rules as well (no longer need
  1403 explicit make_elim);
  1404 
  1405 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1406   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1407 use instead the strong form,
  1408   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1409 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1410 from destruct-rules;
  1411 
  1412 * Provers: Simplifier.easy_setup provides a fast path to basic
  1413 Simplifier setup for new object-logics;
  1414 
  1415 * Pure: AST translation rules no longer require constant head on LHS;
  1416 
  1417 * Pure: improved name spaces: ambiguous output is qualified; support
  1418 for hiding of names;
  1419 
  1420 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1421 XSYMBOL_HOME; no longer need to do manual configuration in most
  1422 situations;
  1423 
  1424 * system: compression of ML heaps images may now be controlled via -c
  1425 option of isabelle and isatool usedir (currently only observed by
  1426 Poly/ML);
  1427 
  1428 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1429 useful for remote X11);
  1430 
  1431 * system: provide TAGS file for Isabelle sources;
  1432 
  1433 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1434 order;
  1435 
  1436 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1437 timing flag supersedes proof_timing and Toplevel.trace;
  1438 
  1439 * ML: new combinators |>> and |>>> for incremental transformations
  1440 with secondary results (e.g. certain theory extensions):
  1441 
  1442 * ML: PureThy.add_defs gets additional argument to indicate potential
  1443 overloading (usually false);
  1444 
  1445 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1446 results;
  1447 
  1448 
  1449 
  1450 New in Isabelle99 (October 1999)
  1451 --------------------------------
  1452 
  1453 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1454 
  1455 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1456 are no longer simplified.  (This allows the simplifier to unfold recursive
  1457 functional programs.)  To restore the old behaviour, declare
  1458 
  1459     Delcongs [if_weak_cong];
  1460 
  1461 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1462 complement;
  1463 
  1464 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1465 
  1466 * HOL/datatype: mutual_induct_tac no longer exists --
  1467   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1468 
  1469 * HOL/typedef: fixed type inference for representing set; type
  1470 arguments now have to occur explicitly on the rhs as type constraints;
  1471 
  1472 * ZF: The con_defs part of an inductive definition may no longer refer
  1473 to constants declared in the same theory;
  1474 
  1475 * HOL, ZF: the function mk_cases, generated by the inductive
  1476 definition package, has lost an argument.  To simplify its result, it
  1477 uses the default simpset instead of a supplied list of theorems.
  1478 
  1479 * HOL/List: the constructors of type list are now Nil and Cons;
  1480 
  1481 * Simplifier: the type of the infix ML functions
  1482         setSSolver addSSolver setSolver addSolver
  1483 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1484 for packaging solvers. A solver is created via
  1485         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1486 where the string argument is only a comment.
  1487 
  1488 
  1489 *** Proof tools ***
  1490 
  1491 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1492 decision procedure for linear arithmetic. Currently it is used for
  1493 types `nat', `int', and `real' in HOL (see below); it can, should and
  1494 will be instantiated for other types and logics as well.
  1495 
  1496 * The simplifier now accepts rewrite rules with flexible heads, eg
  1497      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1498   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1499   matching.
  1500 
  1501 
  1502 *** General ***
  1503 
  1504 * New Isabelle/Isar subsystem provides an alternative to traditional
  1505 tactical theorem proving; together with the ProofGeneral/isar user
  1506 interface it offers an interactive environment for developing human
  1507 readable proof documents (Isar == Intelligible semi-automated
  1508 reasoning); for further information see isatool doc isar-ref,
  1509 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1510 
  1511 * improved and simplified presentation of theories: better HTML markup
  1512 (including colors), graph views in several sizes; isatool usedir now
  1513 provides a proper interface for user theories (via -P option); actual
  1514 document preparation based on (PDF)LaTeX is available as well (for
  1515 new-style theories only); see isatool doc system for more information;
  1516 
  1517 * native support for Proof General, both for classic Isabelle and
  1518 Isabelle/Isar;
  1519 
  1520 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1521 using the graph browser tool;
  1522 
  1523 * Isabelle manuals now also available as PDF;
  1524 
  1525 * theory loader rewritten from scratch (may not be fully
  1526 bug-compatible); old loadpath variable has been replaced by show_path,
  1527 add_path, del_path, reset_path functions; new operations such as
  1528 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1529 isatool doc ref);
  1530 
  1531 * improved isatool install: option -k creates KDE application icon,
  1532 option -p DIR installs standalone binaries;
  1533 
  1534 * added ML_PLATFORM setting (useful for cross-platform installations);
  1535 more robust handling of platform specific ML images for SML/NJ;
  1536 
  1537 * the settings environment is now statically scoped, i.e. it is never
  1538 created again in sub-processes invoked from isabelle, isatool, or
  1539 Isabelle;
  1540 
  1541 * path element specification '~~' refers to '$ISABELLE_HOME';
  1542 
  1543 * in locales, the "assumes" and "defines" parts may be omitted if
  1544 empty;
  1545 
  1546 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1547 long arrows);
  1548 
  1549 * new print_mode "HTML";
  1550 
  1551 * new flag show_tags controls display of tags of theorems (which are
  1552 basically just comments that may be attached by some tools);
  1553 
  1554 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1555 mode and goal output format:
  1556 
  1557 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1558 244c244
  1559 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1560 ---
  1561 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1562 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1563 181c181
  1564 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1565 ---
  1566 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1567 
  1568 * function bind_thms stores lists of theorems (cf. bind_thm);
  1569 
  1570 * new shorthand tactics ftac, eatac, datac, fatac;
  1571 
  1572 * qed (and friends) now accept "" as result name; in that case the
  1573 theorem is not stored, but proper checks and presentation of the
  1574 result still apply;
  1575 
  1576 * theorem database now also indexes constants "Trueprop", "all",
  1577 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1578 
  1579 
  1580 *** HOL ***
  1581 
  1582 ** HOL arithmetic **
  1583 
  1584 * There are now decision procedures for linear arithmetic over nat and
  1585 int:
  1586 
  1587 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1588 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1589 are treated as atomic; subformulae not involving type `nat' or `int'
  1590 are ignored; quantified subformulae are ignored unless they are
  1591 positive universal or negative existential. The tactic has to be
  1592 invoked by hand and can be a little bit slow. In particular, the
  1593 running time is exponential in the number of occurrences of `min' and
  1594 `max', and `-' on `nat'.
  1595 
  1596 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1597 (negated) (in)equalities among the premises and the conclusion into
  1598 account (i.e. no compound formulae) and does not know about `min' and
  1599 `max', and `-' on `nat'. It is fast and is used automatically by the
  1600 simplifier.
  1601 
  1602 NB: At the moment, these decision procedures do not cope with mixed
  1603 nat/int formulae where the two parts interact, such as `m < n ==>
  1604 int(m) < int(n)'.
  1605 
  1606 * HOL/Numeral provides a generic theory of numerals (encoded
  1607 efficiently as bit strings); setup for types nat/int/real is in place;
  1608 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1609 int, existing theories and proof scripts may require a few additional
  1610 type constraints;
  1611 
  1612 * integer division and remainder can now be performed on constant
  1613 arguments;
  1614 
  1615 * many properties of integer multiplication, division and remainder
  1616 are now available;
  1617 
  1618 * An interface to the Stanford Validity Checker (SVC) is available through the
  1619 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1620 are proved automatically.  SVC must be installed separately, and its results
  1621 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1622 invocation of the underlying oracle).  For SVC see
  1623   http://verify.stanford.edu/SVC
  1624 
  1625 * IsaMakefile: the HOL-Real target now builds an actual image;
  1626 
  1627 
  1628 ** HOL misc **
  1629 
  1630 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1631 (in Isabelle/Isar) -- by Gertrud Bauer;
  1632 
  1633 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1634 analysis for assembly languages with subtypes;
  1635 
  1636 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1637 -- avoids syntactic ambiguities and treats state, transition, and
  1638 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1639 changed syntax and (many) tactics;
  1640 
  1641 * HOL/inductive: Now also handles more general introduction rules such
  1642   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1643   theorems are now maintained within the theory (maintained via the
  1644   "mono" attribute);
  1645 
  1646 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1647   (using function types) such as
  1648 
  1649   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1650 
  1651 * HOL/record: record_simproc (part of the default simpset) takes care
  1652 of selectors applied to updated records; record_split_tac is no longer
  1653 part of the default claset; update_defs may now be removed from the
  1654 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1655 
  1656   claset_ref () := claset() addSWrapper record_split_wrapper;
  1657   Delsimprocs [record_simproc]
  1658 
  1659 * HOL/typedef: fixed type inference for representing set; type
  1660 arguments now have to occur explicitly on the rhs as type constraints;
  1661 
  1662 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1663 names rather than an ML expression;
  1664 
  1665 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1666 supplied later.  Program schemes can be defined, such as
  1667     "While B C s = (if B s then While B C (C s) else s)"
  1668 where the well-founded relation can be chosen after B and C have been given.
  1669 
  1670 * HOL/List: the constructors of type list are now Nil and Cons;
  1671 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1672 course, ML tools referring to List.list.op # etc. have to be adapted;
  1673 
  1674 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1675 disabled by default; run isabelle with option -m HOL to get back to
  1676 the original Gordon/HOL-style output;
  1677 
  1678 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1679 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1680 
  1681 * HOL basic syntax simplified (more orthogonal): all variants of
  1682 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1683 Eps operator is provided as well: "SOME x. P[x]";
  1684 
  1685 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1686 
  1687 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1688 thus available for user theories;
  1689 
  1690 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1691 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1692 time;
  1693 
  1694 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1695 several times and then mp;
  1696 
  1697 
  1698 *** LK ***
  1699 
  1700 * the notation <<...>> is now available as a notation for sequences of
  1701 formulas;
  1702 
  1703 * the simplifier is now installed
  1704 
  1705 * the axiom system has been generalized (thanks to Soren Heilmann)
  1706 
  1707 * the classical reasoner now has a default rule database
  1708 
  1709 
  1710 *** ZF ***
  1711 
  1712 * new primrec section allows primitive recursive functions to be given
  1713 directly (as in HOL) over datatypes and the natural numbers;
  1714 
  1715 * new tactics induct_tac and exhaust_tac for induction (or case
  1716 analysis) over datatypes and the natural numbers;
  1717 
  1718 * the datatype declaration of type T now defines the recursor T_rec;
  1719 
  1720 * simplification automatically does freeness reasoning for datatype
  1721 constructors;
  1722 
  1723 * automatic type-inference, with AddTCs command to insert new
  1724 type-checking rules;
  1725 
  1726 * datatype introduction rules are now added as Safe Introduction rules
  1727 to the claset;
  1728 
  1729 * the syntax "if P then x else y" is now available in addition to
  1730 if(P,x,y);
  1731 
  1732 
  1733 *** Internal programming interfaces ***
  1734 
  1735 * tuned simplifier trace output; new flag debug_simp;
  1736 
  1737 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1738 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1739 
  1740 * AxClass.axclass_tac lost the theory argument;
  1741 
  1742 * tuned current_goals_markers semantics: begin / end goal avoids
  1743 printing empty lines;
  1744 
  1745 * removed prs and prs_fn hook, which was broken because it did not
  1746 include \n in its semantics, forcing writeln to add one
  1747 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1748 string -> unit if you really want to output text without newline;
  1749 
  1750 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1751 plain output, interface builders may have to enable 'isabelle_font'
  1752 mode to get Isabelle font glyphs as before;
  1753 
  1754 * refined token_translation interface; INCOMPATIBILITY: output length
  1755 now of type real instead of int;
  1756 
  1757 * theory loader actions may be traced via new ThyInfo.add_hook
  1758 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1759 your own database of information attached to *whole* theories -- as
  1760 opposed to intra-theory data slots offered via TheoryDataFun;
  1761 
  1762 * proper handling of dangling sort hypotheses (at last!);
  1763 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1764 extra sort hypotheses that can be witnessed from the type signature;
  1765 the force_strip_shyps flag is gone, any remaining shyps are simply
  1766 left in the theorem (with a warning issued by strip_shyps_warning);
  1767 
  1768 
  1769 
  1770 New in Isabelle98-1 (October 1998)
  1771 ----------------------------------
  1772 
  1773 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1774 
  1775 * several changes of automated proof tools;
  1776 
  1777 * HOL: major changes to the inductive and datatype packages, including
  1778 some minor incompatibilities of theory syntax;
  1779 
  1780 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1781 called `inj_on';
  1782 
  1783 * HOL: removed duplicate thms in Arith:
  1784   less_imp_add_less  should be replaced by  trans_less_add1
  1785   le_imp_add_le      should be replaced by  trans_le_add1
  1786 
  1787 * HOL: unary minus is now overloaded (new type constraints may be
  1788 required);
  1789 
  1790 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1791 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1792 now taken as an integer constant.
  1793 
  1794 * Pure: ML function 'theory_of' renamed to 'theory';
  1795 
  1796 
  1797 *** Proof tools ***
  1798 
  1799 * Simplifier:
  1800   1. Asm_full_simp_tac is now more aggressive.
  1801      1. It will sometimes reorient premises if that increases their power to
  1802         simplify.
  1803      2. It does no longer proceed strictly from left to right but may also
  1804         rotate premises to achieve further simplification.
  1805      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1806      old Asm_full_simp_tac in that it does not rotate premises.
  1807   2. The simplifier now knows a little bit about nat-arithmetic.
  1808 
  1809 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1810 allows for selected deletion of wrappers, by introduction of names for
  1811 wrapper functionals.  This implies that addbefore, addSbefore,
  1812 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1813 and that adding two tactics with the same name overwrites the first
  1814 one (emitting a warning).
  1815   type wrapper = (int -> tactic) -> (int -> tactic)
  1816   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1817   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1818   delWrapper, delSWrapper: claset *  string            -> claset
  1819   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1820 
  1821 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1822 semantics; addbefore now affects only the unsafe part of step_tac
  1823 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1824 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1825 by Force_tac;
  1826 
  1827 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1828 compWrapper; added safe wrapper (and access functions for it);
  1829 
  1830 * HOL/split_all_tac is now much faster and fails if there is nothing
  1831 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1832 and the names of the automatically generated variables have changed.
  1833 split_all_tac has moved within claset() from unsafe wrappers to safe
  1834 wrappers, which means that !!-bound variables are split much more
  1835 aggressively, and safe_tac and clarify_tac now split such variables.
  1836 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1837 Note: the same holds for record_split_tac, which does the job of
  1838 split_all_tac for record fields.
  1839 
  1840 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1841 permanently to the default simpset using Addsplits just like
  1842 Addsimps. They can be removed via Delsplits just like
  1843 Delsimps. Lower-case versions are also available.
  1844 
  1845 * HOL/Simplifier: The rule split_if is now part of the default
  1846 simpset. This means that the simplifier will eliminate all occurrences
  1847 of if-then-else in the conclusion of a goal. To prevent this, you can
  1848 either remove split_if completely from the default simpset by
  1849 `Delsplits [split_if]' or remove it in a specific call of the
  1850 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1851 other case splitting rules to/from the default simpset: every datatype
  1852 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1853 t is the name of the datatype).
  1854 
  1855 * Classical reasoner / Simplifier combination: new force_tac (and
  1856 derivatives Force_tac, force) combines rewriting and classical
  1857 reasoning (and whatever other tools) similarly to auto_tac, but is
  1858 aimed to solve the given subgoal completely.
  1859 
  1860 
  1861 *** General ***
  1862 
  1863 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1864 and `goalw': the theory is no longer needed as an explicit argument -
  1865 the current theory context is used; assumptions are no longer returned
  1866 at the ML-level unless one of them starts with ==> or !!; it is
  1867 recommended to convert to these new commands using isatool fixgoal
  1868 (backup your sources first!);
  1869 
  1870 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1871 the current theory context, and 'theory' to lookup stored theories;
  1872 
  1873 * new theory section 'locale' for declaring constants, assumptions and
  1874 definitions that have local scope;
  1875 
  1876 * new theory section 'nonterminals' for purely syntactic types;
  1877 
  1878 * new theory section 'setup' for generic ML setup functions
  1879 (e.g. package initialization);
  1880 
  1881 * the distribution now includes Isabelle icons: see
  1882 lib/logo/isabelle-{small,tiny}.xpm;
  1883 
  1884 * isatool install - install binaries with absolute references to
  1885 ISABELLE_HOME/bin;
  1886 
  1887 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1888 
  1889 * print mode 'emacs' reserved for Isamode;
  1890 
  1891 * support multiple print (ast) translations per constant name;
  1892 
  1893 * theorems involving oracles are now printed with a suffixed [!];
  1894 
  1895 
  1896 *** HOL ***
  1897 
  1898 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1899 
  1900 * HOL/inductive package reorganized and improved: now supports mutual
  1901 definitions such as
  1902 
  1903   inductive EVEN ODD
  1904     intrs
  1905       null "0 : EVEN"
  1906       oddI "n : EVEN ==> Suc n : ODD"
  1907       evenI "n : ODD ==> Suc n : EVEN"
  1908 
  1909 new theorem list "elims" contains an elimination rule for each of the
  1910 recursive sets; inductive definitions now handle disjunctive premises
  1911 correctly (also ZF);
  1912 
  1913 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1914 "mutual_induct" no longer exists - the induction rule is always
  1915 contained in "induct";
  1916 
  1917 
  1918 * HOL/datatype package re-implemented and greatly improved: now
  1919 supports mutually recursive datatypes such as
  1920 
  1921   datatype
  1922     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1923             | SUM ('a aexp) ('a aexp)
  1924             | DIFF ('a aexp) ('a aexp)
  1925             | NUM 'a
  1926   and
  1927     'a bexp = LESS ('a aexp) ('a aexp)
  1928             | AND ('a bexp) ('a bexp)
  1929             | OR ('a bexp) ('a bexp)
  1930 
  1931 as well as indirectly recursive datatypes such as
  1932 
  1933   datatype
  1934     ('a, 'b) term = Var 'a
  1935                   | App 'b ((('a, 'b) term) list)
  1936 
  1937 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1938 induction on mutually / indirectly recursive datatypes.
  1939 
  1940 Primrec equations are now stored in theory and can be accessed via
  1941 <function_name>.simps.
  1942 
  1943 INCOMPATIBILITIES:
  1944 
  1945   - Theories using datatypes must now have theory Datatype as an
  1946     ancestor.
  1947   - The specific <typename>.induct_tac no longer exists - use the
  1948     generic induct_tac instead.
  1949   - natE has been renamed to nat.exhaust - use exhaust_tac
  1950     instead of res_inst_tac ... natE. Note that the variable
  1951     names in nat.exhaust differ from the names in natE, this
  1952     may cause some "fragile" proofs to fail.
  1953   - The theorems split_<typename>_case and split_<typename>_case_asm
  1954     have been renamed to <typename>.split and <typename>.split_asm.
  1955   - Since default sorts of type variables are now handled correctly,
  1956     some datatype definitions may have to be annotated with explicit
  1957     sort constraints.
  1958   - Primrec definitions no longer require function name and type
  1959     of recursive argument.
  1960 
  1961 Consider using isatool fixdatatype to adapt your theories and proof
  1962 scripts to the new package (backup your sources first!).
  1963 
  1964 
  1965 * HOL/record package: considerably improved implementation; now
  1966 includes concrete syntax for record types, terms, updates; theorems
  1967 for surjective pairing and splitting !!-bound record variables; proof
  1968 support is as follows:
  1969 
  1970   1) standard conversions (selectors or updates applied to record
  1971 constructor terms) are part of the standard simpset;
  1972 
  1973   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1974 made part of standard simpset and claset via addIffs;
  1975 
  1976   3) a tactic for record field splitting (record_split_tac) is part of
  1977 the standard claset (addSWrapper);
  1978 
  1979 To get a better idea about these rules you may retrieve them via
  1980 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1981 the name of your record type.
  1982 
  1983 The split tactic 3) conceptually simplifies by the following rule:
  1984 
  1985   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1986 
  1987 Thus any record variable that is bound by meta-all will automatically
  1988 blow up into some record constructor term, consequently the
  1989 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1990 solve record problems automatically.
  1991 
  1992 
  1993 * reorganized the main HOL image: HOL/Integ and String loaded by
  1994 default; theory Main includes everything;
  1995 
  1996 * automatic simplification of integer sums and comparisons, using cancellation;
  1997 
  1998 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1999 
  2000 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2001 
  2002 * many new identities for unions, intersections, set difference, etc.;
  2003 
  2004 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2005 called split_if, split_split, split_sum_case and split_nat_case (to go
  2006 with add/delsplits);
  2007 
  2008 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2009 (?x::unit) = (); this is made part of the default simpset, which COULD
  2010 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2011 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2012 unit_abs_eta_conv is added in order to counter the effect of
  2013 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2014 %u.f();
  2015 
  2016 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2017 makes more sense);
  2018 
  2019 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2020   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2021   disjointness reasoning but breaking a few old proofs.
  2022 
  2023 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2024 to 'converse' from 'inverse' (for compatibility with ZF and some
  2025 literature);
  2026 
  2027 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2028 the well-founded relation;
  2029 
  2030 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2031     Compl A.  The "Compl" syntax remains available as input syntax for this
  2032     release ONLY.
  2033 
  2034 * HOL/Update: new theory of function updates:
  2035     f(a:=b) == %x. if x=a then b else f x
  2036 may also be iterated as in f(a:=b,c:=d,...);
  2037 
  2038 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2039 
  2040 * HOL/List:
  2041   - new function list_update written xs[i:=v] that updates the i-th
  2042     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2043   - new function `upt' written [i..j(] which generates the list
  2044     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2045     bound write [i..j], which is a shorthand for [i..j+1(].
  2046   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2047 
  2048 * HOL/Arith:
  2049   - removed 'pred' (predecessor) function;
  2050   - generalized some theorems about n-1;
  2051   - many new laws about "div" and "mod";
  2052   - new laws about greatest common divisors (see theory ex/Primes);
  2053 
  2054 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2055 instead of "inverse";
  2056 
  2057 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2058   of the multiset ordering;
  2059 
  2060 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2061   (not included by default);
  2062 
  2063 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2064 
  2065 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2066   programs, i.e. different program variables may have different types.
  2067 
  2068 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2069   [previously, this check worked only if the rewrite rule was unconditional]
  2070   Now rew can involve either definitions or equalities (either == or =).
  2071 
  2072 
  2073 *** ZF ***
  2074 
  2075 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2076   only the theorems proved on ZF.ML;
  2077 
  2078 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2079   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2080   disjointness reasoning but breaking a few old proofs.
  2081 
  2082 * ZF/Update: new theory of function updates
  2083     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2084   may also be iterated as in f(a:=b,c:=d,...);
  2085 
  2086 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2087 
  2088 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2089   [previously, this check worked only if the rewrite rule was unconditional]
  2090   Now rew can involve either definitions or equalities (either == or =).
  2091 
  2092 * case_tac provided for compatibility with HOL
  2093     (like the old excluded_middle_tac, but with subgoals swapped)
  2094 
  2095 
  2096 *** Internal programming interfaces ***
  2097 
  2098 * Pure: several new basic modules made available for general use, see
  2099 also src/Pure/README;
  2100 
  2101 * improved the theory data mechanism to support encapsulation (data
  2102 kind name replaced by private Object.kind, acting as authorization
  2103 key); new type-safe user interface via functor TheoryDataFun; generic
  2104 print_data function becomes basically useless;
  2105 
  2106 * removed global_names compatibility flag -- all theory declarations
  2107 are qualified by default;
  2108 
  2109 * module Pure/Syntax now offers quote / antiquote translation
  2110 functions (useful for Hoare logic etc. with implicit dependencies);
  2111 see HOL/ex/Antiquote for an example use;
  2112 
  2113 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2114 cterm -> thm;
  2115 
  2116 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2117 subgoal;
  2118 
  2119 * Display.print_goals function moved to Locale.print_goals;
  2120 
  2121 * standard print function for goals supports current_goals_markers
  2122 variable for marking begin of proof, end of proof, start of goal; the
  2123 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2124 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2125 for example;
  2126 
  2127 
  2128 
  2129 New in Isabelle98 (January 1998)
  2130 --------------------------------
  2131 
  2132 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2133 
  2134 * changed lexical syntax of terms / types: dots made part of long
  2135 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2136 
  2137 * simpset (and claset) reference variable replaced by functions
  2138 simpset / simpset_ref;
  2139 
  2140 * no longer supports theory aliases (via merge) and non-trivial
  2141 implicit merge of thms' signatures;
  2142 
  2143 * most internal names of constants changed due to qualified names;
  2144 
  2145 * changed Pure/Sequence interface (see Pure/seq.ML);
  2146 
  2147 
  2148 *** General Changes ***
  2149 
  2150 * hierachically structured name spaces (for consts, types, axms, thms
  2151 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2152 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2153 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2154 long_names for fully qualified output names; NOTE: ML programs
  2155 (special tactics, packages etc.) referring to internal names may have
  2156 to be adapted to cope with fully qualified names; in case of severe
  2157 backward campatibility problems try setting 'global_names' at compile
  2158 time to have enrything declared within a flat name space; one may also
  2159 fine tune name declarations in theories via the 'global' and 'local'
  2160 section;
  2161 
  2162 * reimplemented the implicit simpset and claset using the new anytype
  2163 data filed in signatures; references simpset:simpset ref etc. are
  2164 replaced by functions simpset:unit->simpset and
  2165 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2166 to patch your ML files accordingly;
  2167 
  2168 * HTML output now includes theory graph data for display with Java
  2169 applet or isatool browser; data generated automatically via isatool
  2170 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2171 
  2172 * defs may now be conditional; improved rewrite_goals_tac to handle
  2173 conditional equations;
  2174 
  2175 * defs now admits additional type arguments, using TYPE('a) syntax;
  2176 
  2177 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2178 creates a new theory node; implicit merge of thms' signatures is
  2179 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2180 transfer:theory->thm->thm in (rare) cases;
  2181 
  2182 * improved handling of draft signatures / theories; draft thms (and
  2183 ctyps, cterms) are automatically promoted to real ones;
  2184 
  2185 * slightly changed interfaces for oracles: admit many per theory, named
  2186 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2187 
  2188 * print_goals: optional output of const types (set show_consts and
  2189 show_types);
  2190 
  2191 * improved output of warnings (###) and errors (***);
  2192 
  2193 * subgoal_tac displays a warning if the new subgoal has type variables;
  2194 
  2195 * removed old README and Makefiles;
  2196 
  2197 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2198 
  2199 * removed obsolete init_pps and init_database;
  2200 
  2201 * deleted the obsolete tactical STATE, which was declared by
  2202     fun STATE tacfun st = tacfun st st;
  2203 
  2204 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2205 (which abbreviates $HOME);
  2206 
  2207 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2208 use isatool fixseq to adapt your ML programs (this works for fully
  2209 qualified references to the Sequence structure only!);
  2210 
  2211 * use_thy no longer requires writable current directory; it always
  2212 reloads .ML *and* .thy file, if either one is out of date;
  2213 
  2214 
  2215 *** Classical Reasoner ***
  2216 
  2217 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2218 tactics that use classical reasoning to simplify a subgoal without
  2219 splitting it into several subgoals;
  2220 
  2221 * Safe_tac: like safe_tac but uses the default claset;
  2222 
  2223 
  2224 *** Simplifier ***
  2225 
  2226 * added simplification meta rules:
  2227     (asm_)(full_)simplify: simpset -> thm -> thm;
  2228 
  2229 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2230 logics (again);
  2231 
  2232 * added prems argument to simplification procedures;
  2233 
  2234 * HOL, FOL, ZF: added infix function `addsplits':
  2235   instead of `<simpset> setloop (split_tac <thms>)'
  2236   you can simply write `<simpset> addsplits <thms>'
  2237 
  2238 
  2239 *** Syntax ***
  2240 
  2241 * TYPE('a) syntax for type reflection terms;
  2242 
  2243 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2244 
  2245 * pretty printer: changed order of mixfix annotation preference (again!);
  2246 
  2247 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2248 
  2249 
  2250 *** HOL ***
  2251 
  2252 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2253   with `addloop' of the simplifier to faciliate case splitting in premises.
  2254 
  2255 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2256 
  2257 * HOL/Auth: new protocol proofs including some for the Internet
  2258   protocol TLS;
  2259 
  2260 * HOL/Map: new theory of `maps' a la VDM;
  2261 
  2262 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2263 cancelling out common nat summands from =, <, <= (in)equalities, or
  2264 differences; simplification procedures nat_cancel_factor for
  2265 cancelling common factor from =, <, <= (in)equalities over natural
  2266 sums; nat_cancel contains both kinds of procedures, it is installed by
  2267 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2268 
  2269 * HOL/simplifier: terms of the form
  2270   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2271   are rewritten to
  2272   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2273   and those of the form
  2274   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2275   are rewritten to
  2276   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2277 
  2278 * HOL/datatype
  2279   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2280 
  2281   P(t_case f1 ... fn x) =
  2282      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2283         ...
  2284        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2285      )
  2286 
  2287   and a theorem `split_t_case_asm' of the form
  2288 
  2289   P(t_case f1 ... fn x) =
  2290     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2291         ...
  2292        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2293      )
  2294   which can be added to a simpset via `addsplits'. The existing theorems
  2295   expand_list_case and expand_option_case have been renamed to
  2296   split_list_case and split_option_case.
  2297 
  2298 * HOL/Arithmetic:
  2299   - `pred n' is automatically converted to `n-1'.
  2300     Users are strongly encouraged not to use `pred' any longer,
  2301     because it will disappear altogether at some point.
  2302   - Users are strongly encouraged to write "0 < n" rather than
  2303     "n ~= 0". Theorems and proof tools have been modified towards this
  2304     `standard'.
  2305 
  2306 * HOL/Lists:
  2307   the function "set_of_list" has been renamed "set" (and its theorems too);
  2308   the function "nth" now takes its arguments in the reverse order and
  2309   has acquired the infix notation "!" as in "xs!n".
  2310 
  2311 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2312 
  2313 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2314   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2315 
  2316 * HOL/record: extensible records with schematic structural subtyping
  2317 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2318 still lacks various theorems and concrete record syntax;
  2319 
  2320 
  2321 *** HOLCF ***
  2322 
  2323 * removed "axioms" and "generated by" sections;
  2324 
  2325 * replaced "ops" section by extended "consts" section, which is capable of
  2326   handling the continuous function space "->" directly;
  2327 
  2328 * domain package:
  2329   . proves theorems immediately and stores them in the theory,
  2330   . creates hierachical name space,
  2331   . now uses normal mixfix annotations (instead of cinfix...),
  2332   . minor changes to some names and values (for consistency),
  2333   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2334   . separator between mutual domain defs: changed "," to "and",
  2335   . improved handling of sort constraints;  now they have to
  2336     appear on the left-hand side of the equations only;
  2337 
  2338 * fixed LAM <x,y,zs>.b syntax;
  2339 
  2340 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2341 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2342 
  2343 
  2344 *** FOL and ZF ***
  2345 
  2346 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2347   with `addloop' of the simplifier to faciliate case splitting in premises.
  2348 
  2349 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2350 in HOL, they strip ALL and --> from proved theorems;
  2351 
  2352 
  2353 
  2354 New in Isabelle94-8 (May 1997)
  2355 ------------------------------
  2356 
  2357 *** General Changes ***
  2358 
  2359 * new utilities to build / run / maintain Isabelle etc. (in parts
  2360 still somewhat experimental); old Makefiles etc. still functional;
  2361 
  2362 * new 'Isabelle System Manual';
  2363 
  2364 * INSTALL text, together with ./configure and ./build scripts;
  2365 
  2366 * reimplemented type inference for greater efficiency, better error
  2367 messages and clean internal interface;
  2368 
  2369 * prlim command for dealing with lots of subgoals (an easier way of
  2370 setting goals_limit);
  2371 
  2372 
  2373 *** Syntax ***
  2374 
  2375 * supports alternative (named) syntax tables (parser and pretty
  2376 printer); internal interface is provided by add_modesyntax(_i);
  2377 
  2378 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2379 be used in conjunction with the Isabelle symbol font; uses the
  2380 "symbols" syntax table;
  2381 
  2382 * added token_translation interface (may translate name tokens in
  2383 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2384 the current print_mode); IMPORTANT: user print translation functions
  2385 are responsible for marking newly introduced bounds
  2386 (Syntax.mark_boundT);
  2387 
  2388 * token translations for modes "xterm" and "xterm_color" that display
  2389 names in bold, underline etc. or colors (which requires a color
  2390 version of xterm);
  2391 
  2392 * infixes may now be declared with names independent of their syntax;
  2393 
  2394 * added typed_print_translation (like print_translation, but may
  2395 access type of constant);
  2396 
  2397 
  2398 *** Classical Reasoner ***
  2399 
  2400 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2401 some limitations.  Blast_tac...
  2402   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2403   + ignores elimination rules that don't have the correct format
  2404         (the conclusion MUST be a formula variable)
  2405   + ignores types, which can make HOL proofs fail
  2406   + rules must not require higher-order unification, e.g. apply_type in ZF
  2407     [message "Function Var's argument not a bound variable" relates to this]
  2408   + its proof strategy is more general but can actually be slower
  2409 
  2410 * substitution with equality assumptions no longer permutes other
  2411 assumptions;
  2412 
  2413 * minor changes in semantics of addafter (now called addaltern); renamed
  2414 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2415 (and access functions for it);
  2416 
  2417 * improved combination of classical reasoner and simplifier:
  2418   + functions for handling clasimpsets
  2419   + improvement of addss: now the simplifier is called _after_ the
  2420     safe steps.
  2421   + safe variant of addss called addSss: uses safe simplifications
  2422     _during_ the safe steps. It is more complete as it allows multiple
  2423     instantiations of unknowns (e.g. with slow_tac).
  2424 
  2425 *** Simplifier ***
  2426 
  2427 * added interface for simplification procedures (functions that
  2428 produce *proven* rewrite rules on the fly, depending on current
  2429 redex);
  2430 
  2431 * ordering on terms as parameter (used for ordered rewriting);
  2432 
  2433 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2434 
  2435 * the solver is now split into a safe and an unsafe part.
  2436 This should be invisible for the normal user, except that the
  2437 functions setsolver and addsolver have been renamed to setSolver and
  2438 addSolver; added safe_asm_full_simp_tac;
  2439 
  2440 
  2441 *** HOL ***
  2442 
  2443 * a generic induction tactic `induct_tac' which works for all datatypes and
  2444 also for type `nat';
  2445 
  2446 * a generic case distinction tactic `exhaust_tac' which works for all
  2447 datatypes and also for type `nat';
  2448 
  2449 * each datatype comes with a function `size';
  2450 
  2451 * patterns in case expressions allow tuple patterns as arguments to
  2452 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2453 
  2454 * primrec now also works with type nat;
  2455 
  2456 * recdef: a new declaration form, allows general recursive functions to be
  2457 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2458 
  2459 * the constant for negation has been renamed from "not" to "Not" to
  2460 harmonize with FOL, ZF, LK, etc.;
  2461 
  2462 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2463 infinite lists;
  2464 
  2465 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2466 
  2467 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2468 problems in commutative rings, using axiomatic type classes for + and *;
  2469 
  2470 * more examples in HOL/MiniML and HOL/Auth;
  2471 
  2472 * more default rewrite rules for quantifiers, union/intersection;
  2473 
  2474 * a new constant `arbitrary == @x.False';
  2475 
  2476 * HOLCF/IOA replaces old HOL/IOA;
  2477 
  2478 * HOLCF changes: derived all rules and arities
  2479   + axiomatic type classes instead of classes
  2480   + typedef instead of faking type definitions
  2481   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2482   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2483   + eliminated the types void, one, tr
  2484   + use unit lift and bool lift (with translations) instead of one and tr
  2485   + eliminated blift from Lift3.thy (use Def instead of blift)
  2486   all eliminated rules are derived as theorems --> no visible changes ;
  2487 
  2488 
  2489 *** ZF ***
  2490 
  2491 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2492 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2493 as ZF_cs addSIs [equalityI];
  2494 
  2495 
  2496 
  2497 New in Isabelle94-7 (November 96)
  2498 ---------------------------------
  2499 
  2500 * allowing negative levels (as offsets) in prlev and choplev;
  2501 
  2502 * super-linear speedup for large simplifications;
  2503 
  2504 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2505 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2506 FAIL); can suppress it using the command Delsimps (ex_simps @
  2507 all_simps); De Morgan laws are also now included, by default;
  2508 
  2509 * improved printing of ==>  :  ~:
  2510 
  2511 * new object-logic "Sequents" adds linear logic, while replacing LK
  2512 and Modal (thanks to Sara Kalvala);
  2513 
  2514 * HOL/Auth: correctness proofs for authentication protocols;
  2515 
  2516 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2517 examples on HOL/Auth);
  2518 
  2519 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2520 the rewriter and classical reasoner simultaneously;
  2521 
  2522 * function uresult no longer returns theorems in "standard" format;
  2523 regain previous version by: val uresult = standard o uresult;
  2524 
  2525 
  2526 
  2527 New in Isabelle94-6
  2528 -------------------
  2529 
  2530 * oracles -- these establish an interface between Isabelle and trusted
  2531 external reasoners, which may deliver results as theorems;
  2532 
  2533 * proof objects (in particular record all uses of oracles);
  2534 
  2535 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2536 
  2537 * "constdefs" section in theory files;
  2538 
  2539 * "primrec" section (HOL) no longer requires names;
  2540 
  2541 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2542 
  2543 
  2544 
  2545 New in Isabelle94-5
  2546 -------------------
  2547 
  2548 * reduced space requirements;
  2549 
  2550 * automatic HTML generation from theories;
  2551 
  2552 * theory files no longer require "..." (quotes) around most types;
  2553 
  2554 * new examples, including two proofs of the Church-Rosser theorem;
  2555 
  2556 * non-curried (1994) version of HOL is no longer distributed;
  2557 
  2558 
  2559 
  2560 New in Isabelle94-4
  2561 -------------------
  2562 
  2563 * greatly reduced space requirements;
  2564 
  2565 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2566 
  2567 * searchable theorem database (see the section "Retrieving theorems" on
  2568 page 8 of the Reference Manual);
  2569 
  2570 * new examples, including Grabczewski's monumental case study of the
  2571 Axiom of Choice;
  2572 
  2573 * The previous version of HOL renamed to Old_HOL;
  2574 
  2575 * The new version of HOL (previously called CHOL) uses a curried syntax
  2576 for functions.  Application looks like f a b instead of f(a,b);
  2577 
  2578 * Mutually recursive inductive definitions finally work in HOL;
  2579 
  2580 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2581 translates to the operator "split";
  2582 
  2583 
  2584 
  2585 New in Isabelle94-3
  2586 -------------------
  2587 
  2588 * new infix operator, addss, allowing the classical reasoner to
  2589 perform simplification at each step of its search.  Example:
  2590         fast_tac (cs addss ss)
  2591 
  2592 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2593 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2594 look like (a,b) instead of <a,b>;
  2595 
  2596 * PLEASE NOTE: CHOL will eventually replace HOL!
  2597 
  2598 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2599 It translates to the operator "split".  A new theory of integers is available;
  2600 
  2601 * In ZF, integer numerals now denote two's-complement binary integers.
  2602 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2603 
  2604 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2605 of the Axiom of Choice;
  2606 
  2607 
  2608 
  2609 New in Isabelle94-2
  2610 -------------------
  2611 
  2612 * Significantly faster resolution;
  2613 
  2614 * the different sections in a .thy file can now be mixed and repeated
  2615 freely;
  2616 
  2617 * Database of theorems for FOL, HOL and ZF.  New
  2618 commands including qed, qed_goal and bind_thm store theorems in the database.
  2619 
  2620 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2621 a given theory (thms_of), or find out what theory a theorem was proved in
  2622 (theory_of_thm);
  2623 
  2624 * Bugs fixed in the inductive definition and datatype packages;
  2625 
  2626 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2627 and HOL_dup_cs obsolete;
  2628 
  2629 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2630 have been removed;
  2631 
  2632 * Simpler definition of function space in ZF;
  2633 
  2634 * new results about cardinal and ordinal arithmetic in ZF;
  2635 
  2636 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2637 types;
  2638 
  2639 
  2640 $Id$