NEWS
author kleing
Wed Dec 01 06:33:52 2004 +0100 (2004-12-01)
changeset 15350 53d2927d9680
parent 15319 b8da286bb9ad
child 15356 cfd08f5e0bdd
permissions -rw-r--r--
new antiquotations @{lhs thm} and @{rhs thm}
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Document preparation: new antiquotations @{lhs thm} and @{rhs thm}
    10   printing the lhs/rhs of definitions, equations, inequations etc. 
    11 
    12 * isatool usedir: new option -f that allows specification of the ML
    13   file to be used by Isabelle; default is ROOT.ML.
    14 
    15 * Theory headers: the new header syntax for Isar theories is
    16 
    17   theory <name>
    18   imports <theory1> ... <theoryn>
    19   begin
    20 
    21   optionally also with a "files" section. The syntax
    22 
    23   theory <name> = <theory1> + ... + <theoryn>:
    24 
    25   will still be supported for some time but will eventually disappear.
    26   The syntax of old-style theories has not changed.
    27 
    28 * Provers/quasi.ML:  new transitivity reasoners for transitivity only
    29   and quasi orders.
    30 
    31 * Provers/trancl.ML:  new transitivity reasoner for transitive and
    32   reflexive-transitive closure of relations.
    33 
    34 * Provers/blast.ML:  new reference depth_limit to make blast's depth
    35   limit (previously hard-coded with a value of 20) user-definable.
    36 
    37 * Pure: considerably improved version of 'constdefs' command.  Now
    38   performs automatic type-inference of declared constants; additional
    39   support for local structure declarations (cf. locales and HOL
    40   records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    41   to observe strictly sequential dependencies of definitions within a
    42   single 'constdefs' section; moreover, the declared name needs to be
    43   an identifier.  If all fails, consider to fall back on 'consts' and
    44   'defs' separately.
    45 
    46 * Pure: improved indexed syntax and implicit structures.  First of
    47   all, indexed syntax provides a notational device for subscripted
    48   application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    49   expressions.  Secondly, in a local context with structure
    50   declarations, number indexes \<^sub>n or the empty index (default
    51   number 1) refer to a certain fixed variable implicitly; option
    52   show_structs controls printing of implicit structures.  Typical
    53   applications of these concepts involve record types and locales.
    54 
    55 * Pure: clear separation of logical types and nonterminals, where the
    56   latter may only occur in 'syntax' specifications or type
    57   abbreviations.  Before that distinction was only partially
    58   implemented via type class "logic" vs. "{}".  Potential
    59   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
    60   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
    61   specifications may require further adaption (e.g. Cube/Base.thy).
    62 
    63 * Pure: removed obsolete type class "logic", use the top sort {}
    64   instead.  Note that non-logical types should be declared as
    65   'nonterminals' rather than 'types'.  INCOMPATIBILITY for new
    66   object-logic specifications.
    67 
    68 * Pure: print_tac now outputs the goal through the trace channel.
    69 
    70 * Pure: reference Namespace.unique_names included.  If true the
    71   (shortest) namespace-prefix is printed to disambiguate conflicts (as
    72   yet). If false the first entry wins (as during parsing). Default
    73   value is true.
    74 
    75 * Pure: tuned internal renaming of symbolic identifiers -- attach
    76   primes instead of base 26 numbers.
    77 
    78 * Pure/Syntax: inner syntax includes (*(*nested*) comments*).
    79 
    80 * Pure/Syntax: pretty pinter now supports unbreakable blocks,
    81   specified in mixfix annotations as "(00...)".
    82 
    83 * Pure/Syntax: 'advanced' translation functions (parse_translation
    84   etc.) may depend on the signature of the theory context being
    85   presently used for parsing/printing, see also isar-ref manual.
    86 
    87 * Pure/Simplifier: simplification procedures may now take the current
    88   simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
    89   interface), which is very useful for calling the Simplifier
    90   recursively.  Minor INCOMPATIBILITY: the 'prems' argument of
    91   simprocs is gone -- use prems_of_ss on the simpset instead.
    92   Moreover, the low-level mk_simproc no longer applies Logic.varify
    93   internally, to allow for use in a context of fixed variables.
    94 
    95 * Provers: Simplifier and Classical Reasoner now support proof context
    96   dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
    97   components are stored in the theory and patched into the
    98   simpset/claset when used in an Isar proof context.  Context
    99   dependent components are maintained by the following theory
   100   operations:
   101 
   102     Simplifier.add_context_simprocs
   103     Simplifier.del_context_simprocs
   104     Simplifier.set_context_subgoaler
   105     Simplifier.reset_context_subgoaler
   106     Simplifier.add_context_looper
   107     Simplifier.del_context_looper
   108     Simplifier.add_context_unsafe_solver
   109     Simplifier.add_context_safe_solver
   110 
   111     Classical.add_context_safe_wrapper
   112     Classical.del_context_safe_wrapper
   113     Classical.add_context_unsafe_wrapper
   114     Classical.del_context_unsafe_wrapper
   115 
   116   IMPORTANT NOTE: proof tools (methods etc.) need to use
   117   local_simpset_of and local_claset_of to instead of the primitive
   118   Simplifier.get_local_simpset and Classical.get_local_claset,
   119   respectively, in order to see the context dependent fields!
   120 
   121 * Document preparation: antiquotations now provide the option
   122   'locale=NAME' to specify an alternative context used for evaluating
   123   and printing the subsequent argument, as in @{thm [locale=LC]
   124   fold_commute}, for example.
   125 
   126 * Document preparation: commands 'display_drafts' and 'print_drafts'
   127   perform simple output of raw sources.  Only those symbols that do
   128   not require additional LaTeX packages (depending on comments in
   129   isabellesym.sty) are displayed properly, everything else is left
   130   verbatim.  We use isatool display and isatool print as front ends;
   131   these are subject to the DVI_VIEWER and PRINT_COMMAND settings,
   132   respectively.
   133 
   134 * ML: output via the Isabelle channels of writeln/warning/error
   135   etc. is now passed through Output.output, with a hook for arbitrary
   136   transformations depending on the print_mode (cf. Output.add_mode --
   137   the first active mode that provides a output function wins).
   138   Already formatted output may be embedded into further text via
   139   Output.raw; the result of Pretty.string_of/str_of and derived
   140   functions (string_of_term/cterm/thm etc.) is already marked raw to
   141   accommodate easy composition of diagnostic messages etc.
   142   Programmers rarely need to care about Output.output or Output.raw at
   143   all, with some notable exceptions: Output.output is required when
   144   bypassing the standard channels (writeln etc.), or in token
   145   translations to produce properly formatted results; Output.raw is
   146   required when capturing already output material that will eventually
   147   be presented to the user a second time.  For the default print mode,
   148   both Output.output and Output.raw have no effect.
   149 
   150 
   151 *** Isar ***
   152 
   153 * Locales:
   154   - "includes" disallowed in declaration of named locales (command "locale").
   155   - Fixed parameter management in theorem generation for goals with "includes".
   156     INCOMPATIBILITY: rarely, the generated theorem statement is different.
   157  
   158 *** HOL ***
   159 
   160 * Datatype induction via method `induct' now preserves the name of the
   161   induction variable. For example, when proving P(xs::'a list) by induction
   162   on xs, the induction step is now P(xs) ==> P(a#xs) rather than
   163   P(list) ==> P(a#list) as previously.
   164 
   165 * HOL/record: reimplementation of records. Improved scalability for
   166   records with many fields, avoiding performance problems for type
   167   inference. Records are no longer composed of nested field types, but
   168   of nested extension types. Therefore the record type only grows
   169   linear in the number of extensions and not in the number of fields.
   170   The top-level (users) view on records is preserved.  Potential
   171   INCOMPATIBILITY only in strange cases, where the theory depends on
   172   the old record representation. The type generated for a record is
   173   called <record_name>_ext_type.
   174 
   175 * HOL/record: Reference record_quick_and_dirty_sensitive can be
   176   enabled to skip the proofs triggered by a record definition or a
   177   simproc (if quick_and_dirty is enabled). Definitions of large
   178   records can take quite long.
   179 
   180 * HOL/record: "record_upd_simproc" for simplification of multiple
   181   record updates enabled by default.  Moreover, trivial updates are
   182   also removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   183   occasionally, since simplification is more powerful by default.
   184 
   185 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
   186 
   187   syntax (epsilon)
   188     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   189 
   190   The symbol \<some> is displayed as the alternative epsilon of LaTeX
   191   and x-symbol; use option '-m epsilon' to get it actually printed.
   192   Moreover, the mathematically important symbolic identifier
   193   \<epsilon> becomes available as variable, constant etc.
   194 
   195 * HOL/SetInterval: The syntax for open intervals has changed:
   196 
   197   Old         New
   198   {..n(}   -> {..<n}
   199   {)n..}   -> {n<..}
   200   {m..n(}  -> {m..<n}
   201   {)m..n}  -> {m<..n}
   202   {)m..n(} -> {m<..<n}
   203 
   204   The old syntax is still supported but will disappear in the future.
   205   For conversion use the following emacs search and replace patterns:
   206 
   207   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   208   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   209 
   210   They are not perfect but work quite well.
   211 
   212 * HOL: The syntax for 'setsum', summation over finite sets, has changed:
   213 
   214   The syntax for 'setsum (%x. e) A' used to be '\<Sum>x:A. e'
   215   and is now either 'SUM x:A. e' or '\<Sum>x\<in>A. e'.
   216 
   217   There is new syntax for summation over finite sets:
   218 
   219   '\<Sum>x | P. e'    is the same as  'setsum (%x. e) {x. P}'
   220   '\<Sum>x=a..b. e'   is the same as  'setsum (%x. e) {a..b}'
   221   '\<Sum>x=a..<b. e'  is the same as  'setsum (%x. e) {a..<b}'
   222   '\<Sum>x<k. e'      is the same as  'setsum (%x. e) {..<k}'
   223 
   224   Function 'Summation' over nat is gone, its syntax '\<Sum>i<k. e'
   225   now translates into 'setsum' as above.
   226 
   227 * HOL: Finite set induction: In Isar proofs, the insert case is now
   228   "case (insert x F)" instead of the old counterintuitive "case (insert F x)".
   229 
   230 * HOL/Simplifier:
   231 
   232   - Is now set up to reason about transitivity chains involving "trancl"
   233   (r^+) and "rtrancl" (r^*) by setting up tactics provided by
   234   Provers/trancl.ML as additional solvers.  INCOMPATIBILITY: old proofs break
   235   occasionally as simplification may now solve more goals than previously.
   236 
   237   - Converts x <= y into x = y if assumption y <= x is present.  Works for
   238   all partial orders (class "order"), in particular numbers and sets. For
   239   linear orders (e.g. numbers) it treats ~ x < y just like y <= x.
   240 
   241 * HOL: new 'isatool dimacs2hol' to convert files in DIMACS CNF format
   242   (containing Boolean satisfiability problems) into Isabelle/HOL theories.
   243 
   244 
   245 *** HOLCF ***
   246 
   247 * HOLCF: discontinued special version of 'constdefs' (which used to
   248   support continuous functions) in favor of the general Pure one with
   249   full type-inference.
   250 
   251 
   252 *** ZF ***
   253 
   254 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the
   255   First Isomorphism Theorem (on quotienting by the kernel of a
   256   homomorphism).
   257 
   258 * ZF/Simplifier: install second copy of type solver that actually
   259   makes use of TC rules declared to Isar proof contexts (or locales);
   260   the old version is still required for ML proof scripts.
   261 
   262 
   263 
   264 New in Isabelle2004 (April 2004)
   265 --------------------------------
   266 
   267 *** General ***
   268 
   269 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   270   Replaces linorder.ML.
   271 
   272 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   273   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   274   (\<a>...\<z>), are now considered normal letters, and can therefore
   275   be used anywhere where an ASCII letter (a...zA...Z) has until
   276   now. COMPATIBILITY: This obviously changes the parsing of some
   277   terms, especially where a symbol has been used as a binder, say
   278   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   279   as an identifier.  Fix it by inserting a space around former
   280   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   281   existing theory and ML files.
   282 
   283 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   284 
   285 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   286   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   287   a normal (but invisible) letter. For multiple letter subscripts repeat
   288   \<^isub> like this: x\<^isub>1\<^isub>2.
   289 
   290 * Pure: There are now sub-/superscripts that can span more than one
   291   character. Text between \<^bsub> and \<^esub> is set in subscript in
   292   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   293   superscript. The new control characters are not identifier parts.
   294 
   295 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   296   content of "..." to the latex file instead of \isacntrl... . The "..."
   297   may consist of any printable characters excluding the end bracket >.
   298 
   299 * Pure: Using new Isar command "finalconsts" (or the ML functions
   300   Theory.add_finals or Theory.add_finals_i) it is now possible to
   301   declare constants "final", which prevents their being given a definition
   302   later.  It is useful for constants whose behaviour is fixed axiomatically
   303   rather than definitionally, such as the meta-logic connectives.
   304 
   305 * Pure: 'instance' now handles general arities with general sorts
   306   (i.e. intersections of classes),
   307 
   308 * Presentation: generated HTML now uses a CSS style sheet to make layout
   309   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   310   It can be changed to alter the colors/layout of generated pages.
   311 
   312 
   313 *** Isar ***
   314 
   315 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   316   cut_tac, subgoal_tac and thin_tac:
   317   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   318     locales are no longer forced to write Isar proof scripts.
   319     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   320     emulations.
   321   - INCOMPATIBILITY: names of variables to be instantiated may no
   322     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   323     This is consistent with the instantiation attribute "where".
   324 
   325 * Attributes "where" and "of":
   326   - Now take type variables of instantiated theorem into account when reading
   327     the instantiation string.  This fixes a bug that caused instantiated
   328     theorems to have too special types in some circumstances.
   329   - "where" permits explicit instantiations of type variables.
   330 
   331 * Calculation commands "moreover" and "also" no longer interfere with
   332   current facts ("this"), admitting arbitrary combinations with "then"
   333   and derived forms.
   334 
   335 * Locales:
   336   - Goal statements involving the context element "includes" no longer
   337     generate theorems with internal delta predicates (those ending on
   338     "_axioms") in the premise.
   339     Resolve particular premise with <locale>.intro to obtain old form.
   340   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   341     specification and "includes" elements in goal statement.
   342   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   343     [intro?] and [elim?] (respectively) by default.
   344   - Experimental command for instantiation of locales in proof contexts:
   345         instantiate <label>[<attrs>]: <loc>
   346     Instantiates locale <loc> and adds all its theorems to the current context
   347     taking into account their attributes.  Label and attrs are optional
   348     modifiers, like in theorem declarations.  If present, names of
   349     instantiated theorems are qualified with <label>, and the attributes
   350     <attrs> are applied after any attributes these theorems might have already.
   351       If the locale has assumptions, a chained fact of the form
   352     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   353     are derived.  The command does not support old-style locales declared
   354     with "locale (open)".
   355       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   356 
   357 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   358   (Isar) contexts.
   359 
   360 
   361 *** HOL ***
   362 
   363 * Proof import: new image HOL4 contains the imported library from
   364   the HOL4 system with about 2500 theorems. It is imported by
   365   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   366   can be used like any other Isabelle image.  See
   367   HOL/Import/HOL/README for more information.
   368 
   369 * Simplifier:
   370   - Much improved handling of linear and partial orders.
   371     Reasoners for linear and partial orders are set up for type classes
   372     "linorder" and "order" respectively, and are added to the default simpset
   373     as solvers.  This means that the simplifier can build transitivity chains
   374     to solve goals from the assumptions.
   375   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   376     of blast or auto after simplification become unnecessary because the goal
   377     is solved by simplification already.
   378 
   379 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   380     all proved in axiomatic type classes for semirings, rings and fields.
   381 
   382 * Numerics:
   383   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   384     now formalized using the Ring_and_Field theory mentioned above.
   385   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   386     than before, because now they are set up once in a generic manner.
   387   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   388     Look for the general versions in Ring_and_Field (and Power if they concern
   389     exponentiation).
   390 
   391 * Type "rat" of the rational numbers is now available in HOL-Complex.
   392 
   393 * Records:
   394   - Record types are now by default printed with their type abbreviation
   395     instead of the list of all field types. This can be configured via
   396     the reference "print_record_type_abbr".
   397   - Simproc "record_upd_simproc" for simplification of multiple updates added
   398     (not enabled by default).
   399   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   400     EX x. x = sel r to True (not enabled by default).
   401   - Tactic "record_split_simp_tac" to split and simplify records added.
   402 
   403 * 'specification' command added, allowing for definition by
   404   specification.  There is also an 'ax_specification' command that
   405   introduces the new constants axiomatically.
   406 
   407 * arith(_tac) is now able to generate counterexamples for reals as well.
   408 
   409 * HOL-Algebra: new locale "ring" for non-commutative rings.
   410 
   411 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   412   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   413 
   414 * HOL-Matrix: a first theory for matrices in HOL with an application of
   415   matrix theory to linear programming.
   416 
   417 * Unions and Intersections:
   418   The latex output syntax of UN and INT has been changed
   419   from "\Union x \in A. B" to "\Union_{x \in A} B"
   420   i.e. the index formulae has become a subscript.
   421   Similarly for "\Union x. B", and for \Inter instead of \Union.
   422 
   423 * Unions and Intersections over Intervals:
   424   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   425   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   426   like in normal math, and corresponding versions for < and for intersection.
   427 
   428 * ML: the legacy theory structures Int and List have been removed. They had
   429   conflicted with ML Basis Library structures having the same names.
   430 
   431 * 'refute' command added to search for (finite) countermodels.  Only works
   432   for a fragment of HOL.  The installation of an external SAT solver is
   433   highly recommended.  See "HOL/Refute.thy" for details.
   434 
   435 * 'quickcheck' command: Allows to find counterexamples by evaluating
   436   formulae under an assignment of free variables to random values.
   437   In contrast to 'refute', it can deal with inductive datatypes,
   438   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   439   for examples.
   440 
   441 
   442 *** HOLCF ***
   443 
   444 * Streams now come with concatenation and are part of the HOLCF image
   445 
   446 
   447 
   448 New in Isabelle2003 (May 2003)
   449 ------------------------------
   450 
   451 *** General ***
   452 
   453 * Provers/simplifier:
   454 
   455   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   456     Assumptions are now subject to complete mutual simplification,
   457     not just from left to right. The simplifier now preserves
   458     the order of assumptions.
   459 
   460     Potential INCOMPATIBILITY:
   461 
   462     -- simp sometimes diverges where the old version did
   463        not, e.g. invoking simp on the goal
   464 
   465         [| P (f x); y = x; f x = f y |] ==> Q
   466 
   467        now gives rise to the infinite reduction sequence
   468 
   469         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   470 
   471        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   472        kind of problem.
   473 
   474     -- Tactics combining classical reasoner and simplification (such as auto)
   475        are also affected by this change, because many of them rely on
   476        simp. They may sometimes diverge as well or yield a different numbers
   477        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   478        in case of problems. Sometimes subsequent calls to the classical
   479        reasoner will fail because a preceeding call to the simplifier too
   480        eagerly simplified the goal, e.g. deleted redundant premises.
   481 
   482   - The simplifier trace now shows the names of the applied rewrite rules
   483 
   484   - You can limit the number of recursive invocations of the simplifier
   485     during conditional rewriting (where the simplifie tries to solve the
   486     conditions before applying the rewrite rule):
   487     ML "simp_depth_limit := n"
   488     where n is an integer. Thus you can force termination where previously
   489     the simplifier would diverge.
   490 
   491   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   492 
   493   - No longer aborts on failed congruence proof.  Instead, the
   494     congruence is ignored.
   495 
   496 * Pure: New generic framework for extracting programs from constructive
   497   proofs. See HOL/Extraction.thy for an example instantiation, as well
   498   as HOL/Extraction for some case studies.
   499 
   500 * Pure: The main goal of the proof state is no longer shown by default, only
   501 the subgoals. This behaviour is controlled by a new flag.
   502    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   503 (ML: Proof.show_main_goal).
   504 
   505 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   506 rules whose conclusion matches subgoal 1:
   507       PG menu: Isabelle/Isar -> Show me -> matching rules
   508 The rules are ordered by how closely they match the subgoal.
   509 In particular, rules that solve a subgoal outright are displayed first
   510 (or rather last, the way they are printed).
   511 (ML: ProofGeneral.print_intros())
   512 
   513 * Pure: New flag trace_unify_fail causes unification to print
   514 diagnostic information (PG: in trace buffer) when it fails. This is
   515 useful for figuring out why single step proofs like rule, erule or
   516 assumption failed.
   517 
   518 * Pure: Locale specifications now produce predicate definitions
   519 according to the body of text (covering assumptions modulo local
   520 definitions); predicate "loc_axioms" covers newly introduced text,
   521 while "loc" is cumulative wrt. all included locale expressions; the
   522 latter view is presented only on export into the global theory
   523 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   524 on the old view without predicates;
   525 
   526 * Pure: predefined locales "var" and "struct" are useful for sharing
   527 parameters (as in CASL, for example); just specify something like
   528 ``var x + var y + struct M'' as import;
   529 
   530 * Pure: improved thms_containing: proper indexing of facts instead of
   531 raw theorems; check validity of results wrt. current name space;
   532 include local facts of proof configuration (also covers active
   533 locales), cover fixed variables in index; may use "_" in term
   534 specification; an optional limit for the number of printed facts may
   535 be given (the default is 40);
   536 
   537 * Pure: disallow duplicate fact bindings within new-style theory files
   538 (batch-mode only);
   539 
   540 * Provers: improved induct method: assumptions introduced by case
   541 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   542 the goal statement); "foo" still refers to all facts collectively;
   543 
   544 * Provers: the function blast.overloaded has been removed: all constants
   545 are regarded as potentially overloaded, which improves robustness in exchange
   546 for slight decrease in efficiency;
   547 
   548 * Provers/linorder: New generic prover for transitivity reasoning over
   549 linear orders.  Note: this prover is not efficient!
   550 
   551 * Isar: preview of problems to finish 'show' now produce an error
   552 rather than just a warning (in interactive mode);
   553 
   554 
   555 *** HOL ***
   556 
   557 * arith(_tac)
   558 
   559  - Produces a counter example if it cannot prove a goal.
   560    Note that the counter example may be spurious if the goal is not a formula
   561    of quantifier-free linear arithmetic.
   562    In ProofGeneral the counter example appears in the trace buffer.
   563 
   564  - Knows about div k and mod k where k is a numeral of type nat or int.
   565 
   566  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   567    linear arithmetic fails. This takes account of quantifiers and divisibility.
   568    Presburger arithmetic can also be called explicitly via presburger(_tac).
   569 
   570 * simp's arithmetic capabilities have been enhanced a bit: it now
   571 takes ~= in premises into account (by performing a case split);
   572 
   573 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   574 are distributed over a sum of terms;
   575 
   576 * New tactic "trans_tac" and method "trans" instantiate
   577 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   578 "<=", "<" and "=").
   579 
   580 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   581 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   582 
   583 * 'typedef' command has new option "open" to suppress the set
   584 definition;
   585 
   586 * functions Min and Max on finite sets have been introduced (theory
   587 Finite_Set);
   588 
   589 * attribute [symmetric] now works for relations as well; it turns
   590 (x,y) : R^-1 into (y,x) : R, and vice versa;
   591 
   592 * induct over a !!-quantified statement (say !!x1..xn):
   593   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   594 
   595 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   596 %x. None. Warning: empty_def now refers to the previously hidden definition
   597 of the empty set.
   598 
   599 * Algebra: formalization of classical algebra.  Intended as base for
   600 any algebraic development in Isabelle.  Currently covers group theory
   601 (up to Sylow's theorem) and ring theory (Universal Property of
   602 Univariate Polynomials).  Contributions welcome;
   603 
   604 * GroupTheory: deleted, since its material has been moved to Algebra;
   605 
   606 * Complex: new directory of the complex numbers with numeric constants,
   607 nonstandard complex numbers, and some complex analysis, standard and
   608 nonstandard (Jacques Fleuriot);
   609 
   610 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   611 
   612 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   613 Fleuriot);
   614 
   615 * Real/HahnBanach: updated and adapted to locales;
   616 
   617 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   618 Gray and Kramer);
   619 
   620 * UNITY: added the Meier-Sanders theory of progress sets;
   621 
   622 * MicroJava: bytecode verifier and lightweight bytecode verifier
   623 as abstract algorithms, instantiated to the JVM;
   624 
   625 * Bali: Java source language formalization. Type system, operational
   626 semantics, axiomatic semantics. Supported language features:
   627 classes, interfaces, objects,virtual methods, static methods,
   628 static/instance fields, arrays, access modifiers, definite
   629 assignment, exceptions.
   630 
   631 
   632 *** ZF ***
   633 
   634 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   635 universe, etc.);
   636 
   637 * Main ZF: virtually all theories converted to new-style format;
   638 
   639 
   640 *** ML ***
   641 
   642 * Pure: Tactic.prove provides sane interface for internal proofs;
   643 omits the infamous "standard" operation, so this is more appropriate
   644 than prove_goalw_cterm in many situations (e.g. in simprocs);
   645 
   646 * Pure: improved error reporting of simprocs;
   647 
   648 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   649 up simprocs;
   650 
   651 
   652 *** Document preparation ***
   653 
   654 * uses \par instead of \\ for line breaks in theory text. This may
   655 shift some page breaks in large documents. To get the old behaviour
   656 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   657 
   658 * minimized dependencies of isabelle.sty and isabellesym.sty on
   659 other packages
   660 
   661 * \<euro> now needs package babel/greek instead of marvosym (which
   662 broke \Rightarrow)
   663 
   664 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   665 textcomp package)
   666 
   667 
   668 
   669 New in Isabelle2002 (March 2002)
   670 --------------------------------
   671 
   672 *** Document preparation ***
   673 
   674 * greatly simplified document preparation setup, including more
   675 graceful interpretation of isatool usedir -i/-d/-D options, and more
   676 instructive isatool mkdir; users should basically be able to get
   677 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   678 users may run a separate document processing stage manually like this:
   679 "isatool usedir -D output HOL Test && isatool document Test/output";
   680 
   681 * theory dependency graph may now be incorporated into documents;
   682 isatool usedir -g true will produce session_graph.eps/.pdf for use
   683 with \includegraphics of LaTeX;
   684 
   685 * proper spacing of consecutive markup elements, especially text
   686 blocks after section headings;
   687 
   688 * support bold style (for single symbols only), input syntax is like
   689 this: "\<^bold>\<alpha>" or "\<^bold>A";
   690 
   691 * \<bullet> is now output as bold \cdot by default, which looks much
   692 better in printed text;
   693 
   694 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   695 note that these symbols are currently unavailable in Proof General /
   696 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   697 
   698 * isatool latex no longer depends on changed TEXINPUTS, instead
   699 isatool document copies the Isabelle style files to the target
   700 location;
   701 
   702 
   703 *** Isar ***
   704 
   705 * Pure/Provers: improved proof by cases and induction;
   706   - 'case' command admits impromptu naming of parameters (such as
   707     "case (Suc n)");
   708   - 'induct' method divinates rule instantiation from the inductive
   709     claim; no longer requires excessive ?P bindings for proper
   710     instantiation of cases;
   711   - 'induct' method properly enumerates all possibilities of set/type
   712     rules; as a consequence facts may be also passed through *type*
   713     rules without further ado;
   714   - 'induct' method now derives symbolic cases from the *rulified*
   715     rule (before it used to rulify cases stemming from the internal
   716     atomized version); this means that the context of a non-atomic
   717     statement becomes is included in the hypothesis, avoiding the
   718     slightly cumbersome show "PROP ?case" form;
   719   - 'induct' may now use elim-style induction rules without chaining
   720     facts, using ``missing'' premises from the goal state; this allows
   721     rules stemming from inductive sets to be applied in unstructured
   722     scripts, while still benefitting from proper handling of non-atomic
   723     statements; NB: major inductive premises need to be put first, all
   724     the rest of the goal is passed through the induction;
   725   - 'induct' proper support for mutual induction involving non-atomic
   726     rule statements (uses the new concept of simultaneous goals, see
   727     below);
   728   - append all possible rule selections, but only use the first
   729     success (no backtracking);
   730   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   731   - undeclared rule case names default to numbers 1, 2, 3, ...;
   732   - added 'print_induct_rules' (covered by help item in recent Proof
   733     General versions);
   734   - moved induct/cases attributes to Pure, methods to Provers;
   735   - generic method setup instantiated for FOL and HOL;
   736 
   737 * Pure: support multiple simultaneous goal statements, for example
   738 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   739 meta-level mechanism, this acts as if several individual goals had
   740 been stated separately; in particular common proof methods need to be
   741 repeated in order to cover all claims; note that a single elimination
   742 step is *not* sufficient to establish the two conjunctions, so this
   743 fails:
   744 
   745   assume "A & B" then have A and B ..   (*".." fails*)
   746 
   747 better use "obtain" in situations as above; alternative refer to
   748 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   749 
   750 * Pure: proper integration with ``locales''; unlike the original
   751 version by Florian Kammller, Isar locales package high-level proof
   752 contexts rather than raw logical ones (e.g. we admit to include
   753 attributes everywhere); operations on locales include merge and
   754 rename; support for implicit arguments (``structures''); simultaneous
   755 type-inference over imports and text; see also HOL/ex/Locales.thy for
   756 some examples;
   757 
   758 * Pure: the following commands have been ``localized'', supporting a
   759 target locale specification "(in name)": 'lemma', 'theorem',
   760 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   761 stored both within the locale and at the theory level (exported and
   762 qualified by the locale name);
   763 
   764 * Pure: theory goals may now be specified in ``long'' form, with
   765 ad-hoc contexts consisting of arbitrary locale elements. for example
   766 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   767 definitions may be given, too); the result is a meta-level rule with
   768 the context elements being discharged in the obvious way;
   769 
   770 * Pure: new proof command 'using' allows to augment currently used
   771 facts after a goal statement ('using' is syntactically analogous to
   772 'apply', but acts on the goal's facts only); this allows chained facts
   773 to be separated into parts given before and after a claim, as in
   774 ``from a and b have C using d and e <proof>'';
   775 
   776 * Pure: renamed "antecedent" case to "rule_context";
   777 
   778 * Pure: new 'judgment' command records explicit information about the
   779 object-logic embedding (used by several tools internally); no longer
   780 use hard-wired "Trueprop";
   781 
   782 * Pure: added 'corollary' command;
   783 
   784 * Pure: fixed 'token_translation' command;
   785 
   786 * Pure: removed obsolete 'exported' attribute;
   787 
   788 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   789 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   790 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   791 
   792 * Pure: method 'atomize' presents local goal premises as object-level
   793 statements (atomic meta-level propositions); setup controlled via
   794 rewrite rules declarations of 'atomize' attribute; example
   795 application: 'induct' method with proper rule statements in improper
   796 proof *scripts*;
   797 
   798 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   799 now consider the syntactic context of assumptions, giving a better
   800 chance to get type-inference of the arguments right (this is
   801 especially important for locales);
   802 
   803 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   804 mode;
   805 
   806 * Pure/obtain: the formal conclusion "thesis", being marked as
   807 ``internal'', may no longer be reference directly in the text;
   808 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   809 situations;
   810 
   811 * Pure: generic 'sym' attribute which declares a rule both as pure
   812 'elim?' and for the 'symmetric' operation;
   813 
   814 * Pure: marginal comments ``--'' may now occur just anywhere in the
   815 text; the fixed correlation with particular command syntax has been
   816 discontinued;
   817 
   818 * Pure: new method 'rules' is particularly well-suited for proof
   819 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   820 but often produces more compact proof terms with less detours;
   821 
   822 * Pure/Provers/classical: simplified integration with pure rule
   823 attributes and methods; the classical "intro?/elim?/dest?"
   824 declarations coincide with the pure ones; the "rule" method no longer
   825 includes classically swapped intros; "intro" and "elim" methods no
   826 longer pick rules from the context; also got rid of ML declarations
   827 AddXIs/AddXEs/AddXDs; all of this has some potential for
   828 INCOMPATIBILITY;
   829 
   830 * Provers/classical: attribute 'swapped' produces classical inversions
   831 of introduction rules;
   832 
   833 * Provers/simplifier: 'simplified' attribute may refer to explicit
   834 rules instead of full simplifier context; 'iff' attribute handles
   835 conditional rules;
   836 
   837 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   838 
   839 * HOL: 'recdef' now fails on unfinished automated proofs, use
   840 "(permissive)" option to recover old behavior;
   841 
   842 * HOL: 'inductive' no longer features separate (collective) attributes
   843 for 'intros' (was found too confusing);
   844 
   845 * HOL: properly declared induction rules less_induct and
   846 wf_induct_rule;
   847 
   848 
   849 *** HOL ***
   850 
   851 * HOL: moved over to sane numeral syntax; the new policy is as
   852 follows:
   853 
   854   - 0 and 1 are polymorphic constants, which are defined on any
   855   numeric type (nat, int, real etc.);
   856 
   857   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   858   binary representation internally;
   859 
   860   - type nat has special constructor Suc, and generally prefers Suc 0
   861   over 1::nat and Suc (Suc 0) over 2::nat;
   862 
   863 This change may cause significant problems of INCOMPATIBILITY; here
   864 are some hints on converting existing sources:
   865 
   866   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   867   entities, so expressions involving "-" (unary or binary minus) need
   868   to be spaced properly;
   869 
   870   - existing occurrences of "1" may need to be constraint "1::nat" or
   871   even replaced by Suc 0; similar for old "2";
   872 
   873   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   874 
   875   - remove all special provisions on numerals in proofs;
   876 
   877 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   878 representation (depends on bin_arith_simps in the default context);
   879 
   880 * HOL: symbolic syntax for x^2 (numeral 2);
   881 
   882 * HOL: the class of all HOL types is now called "type" rather than
   883 "term"; INCOMPATIBILITY, need to adapt references to this type class
   884 in axclass/classes, instance/arities, and (usually rare) occurrences
   885 in typings (of consts etc.); internally the class is called
   886 "HOL.type", ML programs should refer to HOLogic.typeS;
   887 
   888 * HOL/record package improvements:
   889   - new derived operations "fields" to build a partial record section,
   890     "extend" to promote a fixed record to a record scheme, and
   891     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   892     declared as simp by default;
   893   - shared operations ("more", "fields", etc.) now need to be always
   894     qualified) --- potential INCOMPATIBILITY;
   895   - removed "make_scheme" operations (use "make" with "extend") --
   896     INCOMPATIBILITY;
   897   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   898   - provides cases/induct rules for use with corresponding Isar
   899     methods (for concrete records, record schemes, concrete more
   900     parts, and schematic more parts -- in that order);
   901   - internal definitions directly based on a light-weight abstract
   902     theory of product types over typedef rather than datatype;
   903 
   904 * HOL: generic code generator for generating executable ML code from
   905 specifications; specific support for HOL constructs such as inductive
   906 datatypes and sets, as well as recursive functions; can be invoked
   907 via 'generate_code' theory section;
   908 
   909 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   910 
   911 * HOL: consolidated and renamed several theories.  In particular:
   912         Ord.thy has been absorbed into HOL.thy
   913         String.thy has been absorbed into List.thy
   914 
   915 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   916 (beware of argument permutation!);
   917 
   918 * HOL: linorder_less_split superseded by linorder_cases;
   919 
   920 * HOL/List: "nodups" renamed to "distinct";
   921 
   922 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   923 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   924   - Ex_def has changed, now need to use some_eq_ex
   925 
   926 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   927 in this (rare) case use:
   928 
   929   delSWrapper "split_all_tac"
   930   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   931 
   932 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   933 MAY FAIL;
   934 
   935 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   936 Isabelle's type classes, ^ on functions and relations has too general
   937 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   938 necessary to attach explicit type constraints;
   939 
   940 * HOL/Relation: the prefix name of the infix "O" has been changed from
   941 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   942 renamed accordingly (eg "compI" -> "rel_compI").
   943 
   944 * HOL: syntax translations now work properly with numerals and records
   945 expressions;
   946 
   947 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   948 of "lam" -- INCOMPATIBILITY;
   949 
   950 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   951 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   952 renamed "Product_Type.unit";
   953 
   954 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   955 
   956 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   957 the "cases" method);
   958 
   959 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   960 Florian Kammller);
   961 
   962 * HOL/IMP: updated and converted to new-style theory format; several
   963 parts turned into readable document, with proper Isar proof texts and
   964 some explanations (by Gerwin Klein);
   965 
   966 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   967 
   968 * HOL-Hyperreal is now a logic image;
   969 
   970 
   971 *** HOLCF ***
   972 
   973 * Isar: consts/constdefs supports mixfix syntax for continuous
   974 operations;
   975 
   976 * Isar: domain package adapted to new-style theory format, e.g. see
   977 HOLCF/ex/Dnat.thy;
   978 
   979 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   980 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   981 lift.induct_tac, always use UU instead of Undef;
   982 
   983 * HOLCF/IMP: updated and converted to new-style theory;
   984 
   985 
   986 *** ZF ***
   987 
   988 * Isar: proper integration of logic-specific tools and packages,
   989 including theory commands '(co)inductive', '(co)datatype',
   990 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   991 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   992 
   993 * theory Main no longer includes AC; for the Axiom of Choice, base
   994 your theory on Main_ZFC;
   995 
   996 * the integer library now covers quotients and remainders, with many
   997 laws relating division to addition, multiplication, etc.;
   998 
   999 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1000 typeless version of the formalism;
  1001 
  1002 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1003 format;
  1004 
  1005 * ZF/Induct: new directory for examples of inductive definitions,
  1006 including theory Multiset for multiset orderings; converted to
  1007 new-style theory format;
  1008 
  1009 * ZF: many new theorems about lists, ordinals, etc.;
  1010 
  1011 
  1012 *** General ***
  1013 
  1014 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1015 variable proof controls level of detail: 0 = no proofs (only oracle
  1016 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1017 also ref manual for further ML interfaces;
  1018 
  1019 * Pure/axclass: removed obsolete ML interface
  1020 goal_subclass/goal_arity;
  1021 
  1022 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1023 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1024 separate tokens, so expressions involving minus need to be spaced
  1025 properly;
  1026 
  1027 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1028 rather than "infixl" or "infixr";
  1029 
  1030 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1031 sort constraint specifications in type inference; e.g. "x::_::foo"
  1032 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1033 type variable);
  1034 
  1035 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1036 control output of nested => (types); the default behavior is
  1037 "type_brackets";
  1038 
  1039 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1040 tokens into AST constants;
  1041 
  1042 * Pure/syntax: prefer later declarations of translations and print
  1043 translation functions; potential INCOMPATIBILITY: need to reverse
  1044 multiple declarations for same syntax element constant;
  1045 
  1046 * Pure/show_hyps reset by default (in accordance to existing Isar
  1047 practice);
  1048 
  1049 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1050 addSafter;
  1051 
  1052 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1053 as well;
  1054 
  1055 * system: tested support for MacOS X; should be able to get Isabelle +
  1056 Proof General to work in a plain Terminal after installing Poly/ML
  1057 (e.g. from the Isabelle distribution area) and GNU bash alone
  1058 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1059 support requires further installations, e.g. from
  1060 http://fink.sourceforge.net/);
  1061 
  1062 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1063 
  1064 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1065 of 40 MB), cf. ML_OPTIONS;
  1066 
  1067 * system: Proof General keywords specification is now part of the
  1068 Isabelle distribution (see etc/isar-keywords.el);
  1069 
  1070 * system: support for persistent Proof General sessions (refrain from
  1071 outdating all loaded theories on startup); user may create writable
  1072 logic images like this: ``isabelle -q HOL Test'';
  1073 
  1074 * system: smart selection of Isabelle process versus Isabelle
  1075 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1076 run both "isabelle" and "Isabelle" even if file names are badly
  1077 damaged (executable inspects the case of the first letter of its own
  1078 name); added separate "isabelle-process" and "isabelle-interface";
  1079 
  1080 * system: refrain from any attempt at filtering input streams; no
  1081 longer support ``8bit'' encoding of old isabelle font, instead proper
  1082 iso-latin characters may now be used; the related isatools
  1083 "symbolinput" and "nonascii" have disappeared as well;
  1084 
  1085 * system: removed old "xterm" interface (the print modes "xterm" and
  1086 "xterm_color" are still available for direct use in a suitable
  1087 terminal);
  1088 
  1089 
  1090 
  1091 New in Isabelle99-2 (February 2001)
  1092 -----------------------------------
  1093 
  1094 *** Overview of INCOMPATIBILITIES ***
  1095 
  1096 * HOL: please note that theories in the Library and elsewhere often use the
  1097 new-style (Isar) format; to refer to their theorems in an ML script you must
  1098 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1099 
  1100 * HOL: inductive package no longer splits induction rule aggressively,
  1101 but only as far as specified by the introductions given; the old
  1102 format may be recovered via ML function complete_split_rule or attribute
  1103 'split_rule (complete)';
  1104 
  1105 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1106 gfp_Tarski to gfp_unfold;
  1107 
  1108 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1109 
  1110 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1111 relation); infix "^^" has been renamed "``"; infix "``" has been
  1112 renamed "`"; "univalent" has been renamed "single_valued";
  1113 
  1114 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1115 operation;
  1116 
  1117 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1118 
  1119 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1120 
  1121 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1122 consequence, it is no longer monotonic wrt. the local goal context
  1123 (which is now passed through the inductive cases);
  1124 
  1125 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1126 \<gg> to \<ggreater>;
  1127 
  1128 
  1129 *** Document preparation ***
  1130 
  1131 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1132 available: are "it" for near math-mode best-style output, "sl" for
  1133 slanted text style, and "tt" for plain type-writer; if no
  1134 \isabellestyle command is given, output is according to slanted
  1135 type-writer);
  1136 
  1137 * support sub/super scripts (for single symbols only), input syntax is
  1138 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1139 
  1140 * some more standard symbols; see Appendix A of the system manual for
  1141 the complete list of symbols defined in isabellesym.sty;
  1142 
  1143 * improved isabelle style files; more abstract symbol implementation
  1144 (should now use \isamath{...} and \isatext{...} in custom symbol
  1145 definitions);
  1146 
  1147 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1148 state; Note that presentation of goal states does not conform to
  1149 actual human-readable proof documents.  Please do not include goal
  1150 states into document output unless you really know what you are doing!
  1151 
  1152 * proper indentation of antiquoted output with proportional LaTeX
  1153 fonts;
  1154 
  1155 * no_document ML operator temporarily disables LaTeX document
  1156 generation;
  1157 
  1158 * isatool unsymbolize tunes sources for plain ASCII communication;
  1159 
  1160 
  1161 *** Isar ***
  1162 
  1163 * Pure: Isar now suffers initial goal statements to contain unbound
  1164 schematic variables (this does not conform to actual readable proof
  1165 documents, due to unpredictable outcome and non-compositional proof
  1166 checking); users who know what they are doing may use schematic goals
  1167 for Prolog-style synthesis of proven results;
  1168 
  1169 * Pure: assumption method (an implicit finishing) now handles actual
  1170 rules as well;
  1171 
  1172 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1173 initial goal, declare "that" only as Pure intro (only for single
  1174 steps); the "that" rule assumption may now be involved in implicit
  1175 finishing, thus ".." becomes a feasible for trivial obtains;
  1176 
  1177 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1178 instance proofs may be performed by "..";
  1179 
  1180 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1181 statements as well;
  1182 
  1183 * Pure: more robust selection of calculational rules;
  1184 
  1185 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1186 rule (as well as the assumption rule);
  1187 
  1188 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1189 lemmas, using the graph browser tool;
  1190 
  1191 * Pure: predict failure of "show" in interactive mode;
  1192 
  1193 * Pure: 'thms_containing' now takes actual terms as arguments;
  1194 
  1195 * HOL: improved method 'induct' --- now handles non-atomic goals
  1196 (potential INCOMPATIBILITY); tuned error handling;
  1197 
  1198 * HOL: cases and induct rules now provide explicit hints about the
  1199 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1200 any remaining facts are inserted into the goal verbatim;
  1201 
  1202 * HOL: local contexts (aka cases) may now contain term bindings as
  1203 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1204 the result to be shown in each case;
  1205 
  1206 * HOL: added 'recdef_tc' command;
  1207 
  1208 * isatool convert assists in eliminating legacy ML scripts;
  1209 
  1210 
  1211 *** HOL ***
  1212 
  1213 * HOL/Library: a collection of generic theories to be used together
  1214 with main HOL; the theory loader path already includes this directory
  1215 by default; the following existing theories have been moved here:
  1216 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1217 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1218 
  1219 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1220 modelling and verification task performed in Isabelle/HOL +
  1221 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1222 
  1223 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1224 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1225 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1226 'domain', this makes the theory consistent with mathematical
  1227 literature;
  1228 
  1229 * HOL basics: added overloaded operations "inverse" and "divide"
  1230 (infix "/"), syntax for generic "abs" operation, generic summation
  1231 operator \<Sum>;
  1232 
  1233 * HOL/typedef: simplified package, provide more useful rules (see also
  1234 HOL/subset.thy);
  1235 
  1236 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1237 now expressed as a proper nested rule (old-style tactic scripts may
  1238 require atomize_strip_tac to cope with non-atomic premises);
  1239 
  1240 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1241 to "split_conv" (old name still available for compatibility);
  1242 
  1243 * HOL: improved concrete syntax for strings (e.g. allows translation
  1244 rules with string literals);
  1245 
  1246 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1247  and Fleuriot's mechanization of analysis, including the transcendental
  1248  functions for the reals;
  1249 
  1250 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1251 
  1252 
  1253 *** CTT ***
  1254 
  1255 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1256 "lam" is displayed as TWO lambda-symbols
  1257 
  1258 * CTT: theory Main now available, containing everything (that is, Bool
  1259 and Arith);
  1260 
  1261 
  1262 *** General ***
  1263 
  1264 * Pure: the Simplifier has been implemented properly as a derived rule
  1265 outside of the actual kernel (at last!); the overall performance
  1266 penalty in practical applications is about 50%, while reliability of
  1267 the Isabelle inference kernel has been greatly improved;
  1268 
  1269 * print modes "brackets" and "no_brackets" control output of nested =>
  1270 (types) and ==> (props); the default behaviour is "brackets";
  1271 
  1272 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1273 as assumptions as well;
  1274 
  1275 * system: support Poly/ML 4.0;
  1276 
  1277 * system: isatool install handles KDE version 1 or 2;
  1278 
  1279 
  1280 
  1281 New in Isabelle99-1 (October 2000)
  1282 ----------------------------------
  1283 
  1284 *** Overview of INCOMPATIBILITIES ***
  1285 
  1286 * HOL: simplification of natural numbers is much changed; to partly
  1287 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1288 issue the following ML commands:
  1289 
  1290   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1291   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1292 
  1293 * HOL: simplification no longer dives into case-expressions; this is
  1294 controlled by "t.weak_case_cong" for each datatype t;
  1295 
  1296 * HOL: nat_less_induct renamed to less_induct;
  1297 
  1298 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1299 fixsome to patch .thy and .ML sources automatically;
  1300 
  1301   select_equality  -> some_equality
  1302   select_eq_Ex     -> some_eq_ex
  1303   selectI2EX       -> someI2_ex
  1304   selectI2         -> someI2
  1305   selectI          -> someI
  1306   select1_equality -> some1_equality
  1307   Eps_sym_eq       -> some_sym_eq_trivial
  1308   Eps_eq           -> some_eq_trivial
  1309 
  1310 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1311 
  1312 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1313 instead);
  1314 
  1315 * HOL: the recursion equations generated by 'recdef' are now called
  1316 f.simps instead of f.rules;
  1317 
  1318 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1319 
  1320 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1321 sometimes be needed;
  1322 
  1323 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1324 
  1325 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1326 
  1327 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1328 product is now "<*>" instead of "Times"; the lexicographic product is
  1329 now "<*lex*>" instead of "**";
  1330 
  1331 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1332 of main HOL, but was unused); better use HOL's datatype package;
  1333 
  1334 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1335 the old syntax may be recovered as follows:
  1336 
  1337   syntax (symbols)
  1338     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1339       (infixl "\\<oplus>" 100)
  1340 
  1341 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1342 
  1343 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1344 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1345 internally;
  1346 
  1347 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1348 changed from A/r to A//r;
  1349 
  1350 * ZF: new treatment of arithmetic (nat & int) may break some old
  1351 proofs;
  1352 
  1353 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1354 rulify -> rule_format, elimify -> elim_format, ...);
  1355 
  1356 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1357 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1358 should have to change intro!! to intro? only); replaced "delrule" by
  1359 "rule del";
  1360 
  1361 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1362 
  1363 * Provers: strengthened force_tac by using new first_best_tac;
  1364 
  1365 * LaTeX document preparation: several changes of isabelle.sty (see
  1366 lib/texinputs);
  1367 
  1368 
  1369 *** Document preparation ***
  1370 
  1371 * formal comments (text blocks etc.) in new-style theories may now
  1372 contain antiquotations of thm/prop/term/typ/text to be presented
  1373 according to latex print mode; concrete syntax is like this:
  1374 @{term[show_types] "f(x) = a + x"};
  1375 
  1376 * isatool mkdir provides easy setup of Isabelle session directories,
  1377 including proper document sources;
  1378 
  1379 * generated LaTeX sources are now deleted after successful run
  1380 (isatool document -c); may retain a copy somewhere else via -D option
  1381 of isatool usedir;
  1382 
  1383 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1384 style files, achieving self-contained LaTeX sources and simplifying
  1385 LaTeX debugging;
  1386 
  1387 * old-style theories now produce (crude) LaTeX output as well;
  1388 
  1389 * browser info session directories are now self-contained (may be put
  1390 on WWW server seperately); improved graphs of nested sessions; removed
  1391 graph for 'all sessions';
  1392 
  1393 * several improvements in isabelle style files; \isabellestyle{it}
  1394 produces fake math mode output; \isamarkupheader is now \section by
  1395 default; see lib/texinputs/isabelle.sty etc.;
  1396 
  1397 
  1398 *** Isar ***
  1399 
  1400 * Isar/Pure: local results and corresponding term bindings are now
  1401 subject to Hindley-Milner polymorphism (similar to ML); this
  1402 accommodates incremental type-inference very nicely;
  1403 
  1404 * Isar/Pure: new derived language element 'obtain' supports
  1405 generalized existence reasoning;
  1406 
  1407 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1408 support accumulation of results, without applying any rules yet;
  1409 useful to collect intermediate results without explicit name
  1410 references, and for use with transitivity rules with more than 2
  1411 premises;
  1412 
  1413 * Isar/Pure: scalable support for case-analysis type proofs: new
  1414 'case' language element refers to local contexts symbolically, as
  1415 produced by certain proof methods; internally, case names are attached
  1416 to theorems as "tags";
  1417 
  1418 * Isar/Pure: theory command 'hide' removes declarations from
  1419 class/type/const name spaces;
  1420 
  1421 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1422 indicate potential overloading;
  1423 
  1424 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1425 
  1426 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1427 "{a,b,c}" instead of {a,b,c};
  1428 
  1429 * Isar/Pure now provides its own version of intro/elim/dest
  1430 attributes; useful for building new logics, but beware of confusion
  1431 with the version in Provers/classical;
  1432 
  1433 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1434 case name 'antecedent';
  1435 
  1436 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1437 to the current context is now done automatically);
  1438 
  1439 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1440 for definining proof methods in ML;
  1441 
  1442 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1443 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1444 most cases, one should have to change intro!! to intro? only);
  1445 replaced "delrule" by "rule del";
  1446 
  1447 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1448 'symmetric' attribute (the latter supercedes [RS sym]);
  1449 
  1450 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1451 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1452 well (including splits);
  1453 
  1454 * Isar/Provers: Simplifier and Classical methods now support all kind
  1455 of modifiers used in the past, including 'cong', 'iff', etc.
  1456 
  1457 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1458 of Simplifier and Classical reasoner);
  1459 
  1460 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1461 now support named cases; major packages (inductive, datatype, primrec,
  1462 recdef) support case names and properly name parameters;
  1463 
  1464 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1465 monotonicity conditions are extracted to be proven at end of
  1466 calculations;
  1467 
  1468 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1469 method anyway;
  1470 
  1471 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1472 split_if split_if_asm; datatype package provides theorems foo.splits =
  1473 foo.split foo.split_asm for each datatype;
  1474 
  1475 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1476 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1477 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1478 use "(cases (simplified))" method in proper proof texts);
  1479 
  1480 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1481 
  1482 * Isar: names of theorems etc. may be natural numbers as well;
  1483 
  1484 * Isar: 'pr' command: optional arguments for goals_limit and
  1485 ProofContext.prems_limit; no longer prints theory contexts, but only
  1486 proof states;
  1487 
  1488 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1489 additional print modes to be specified; e.g. "pr(latex)" will print
  1490 proof state according to the Isabelle LaTeX style;
  1491 
  1492 * Isar: improved support for emulating tactic scripts, including proof
  1493 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1494 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1495 (for HOL datatypes);
  1496 
  1497 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1498 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1499 'proof method scripts' have to be in depth-first order;
  1500 
  1501 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1502 
  1503 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1504 should instead use individual commands for printing items
  1505 (print_commands, print_methods etc.);
  1506 
  1507 * Isar: added 'nothing' --- the empty list of theorems;
  1508 
  1509 
  1510 *** HOL ***
  1511 
  1512 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1513 corresponding virtual machine and a specification of its bytecode
  1514 verifier and a lightweight bytecode verifier, including proofs of
  1515 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1516 Cornelia Pusch (see also the homepage of project Bali at
  1517 http://isabelle.in.tum.de/Bali/);
  1518 
  1519 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1520 Clemens Ballarin;
  1521 
  1522 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1523 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1524 Rasmussen;
  1525 
  1526 * HOL/Lattice: fundamental concepts of lattice theory and order
  1527 structures, including duals, properties of bounds versus algebraic
  1528 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1529 Theorem for complete lattices etc.; may also serve as a demonstration
  1530 for abstract algebraic reasoning using axiomatic type classes, and
  1531 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1532 
  1533 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1534 von Oheimb;
  1535 
  1536 * HOL/IMPP: extension of IMP with local variables and mutually
  1537 recursive procedures, by David von Oheimb;
  1538 
  1539 * HOL/Lambda: converted into new-style theory and document;
  1540 
  1541 * HOL/ex/Multiquote: example of multiple nested quotations and
  1542 anti-quotations -- basically a generalized version of de-Bruijn
  1543 representation; very useful in avoiding lifting of operations;
  1544 
  1545 * HOL/record: added general record equality rule to simpset; fixed
  1546 select-update simplification procedure to handle extended records as
  1547 well; admit "r" as field name;
  1548 
  1549 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1550 other numeric types and also as the identity of groups, rings, etc.;
  1551 
  1552 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1553 Types nat and int belong to this axclass;
  1554 
  1555 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1556    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1557    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1558   two terms #m*u and #n*u are replaced by #(m+n)*u
  1559     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1560   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1561     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1562 
  1563 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1564 powerful prover for predicate logic but knows nothing of clasets; see
  1565 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1566 
  1567 * HOL: new version of "case_tac" subsumes both boolean case split and
  1568 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1569 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1570 
  1571 * HOL: simplification no longer dives into case-expressions: only the
  1572 selector expression is simplified, but not the remaining arms; to
  1573 enable full simplification of case-expressions for datatype t, you may
  1574 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1575 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1576 
  1577 * HOL/recdef: the recursion equations generated by 'recdef' for
  1578 function 'f' are now called f.simps instead of f.rules; if all
  1579 termination conditions are proved automatically, these simplification
  1580 rules are added to the simpset, as in primrec; rules may be named
  1581 individually as well, resulting in a separate list of theorems for
  1582 each equation;
  1583 
  1584 * HOL/While is a new theory that provides a while-combinator. It
  1585 permits the definition of tail-recursive functions without the
  1586 provision of a termination measure. The latter is necessary once the
  1587 invariant proof rule for while is applied.
  1588 
  1589 * HOL: new (overloaded) notation for the set of elements below/above
  1590 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1591 
  1592 * HOL: theorems impI, allI, ballI bound as "strip";
  1593 
  1594 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1595 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1596 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1597 
  1598 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1599 
  1600 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1601 main HOL, but was unused);
  1602 
  1603 * HOL: fewer consts declared as global (e.g. have to refer to
  1604 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1605 
  1606 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1607 in case of overlap with user translations (e.g. judgements over
  1608 tuples); (note that the underlying logical represenation is still
  1609 bogus);
  1610 
  1611 
  1612 *** ZF ***
  1613 
  1614 * ZF: simplification automatically cancels common terms in arithmetic
  1615 expressions over nat and int;
  1616 
  1617 * ZF: new treatment of nat to minimize type-checking: all operators
  1618 coerce their operands to a natural number using the function natify,
  1619 making the algebraic laws unconditional;
  1620 
  1621 * ZF: as above, for int: operators coerce their operands to an integer
  1622 using the function intify;
  1623 
  1624 * ZF: the integer library now contains many of the usual laws for the
  1625 orderings, including $<=, and monotonicity laws for $+ and $*;
  1626 
  1627 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1628 simplification;
  1629 
  1630 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1631 to the simplifier and classical reasoner simultaneously;
  1632 
  1633 
  1634 *** General ***
  1635 
  1636 * Provers: blast_tac now handles actual object-logic rules as
  1637 assumptions; note that auto_tac uses blast_tac internally as well;
  1638 
  1639 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1640 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1641 
  1642 * Provers: delrules now handles destruct rules as well (no longer need
  1643 explicit make_elim);
  1644 
  1645 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1646   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1647 use instead the strong form,
  1648   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1649 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1650 from destruct-rules;
  1651 
  1652 * Provers: Simplifier.easy_setup provides a fast path to basic
  1653 Simplifier setup for new object-logics;
  1654 
  1655 * Pure: AST translation rules no longer require constant head on LHS;
  1656 
  1657 * Pure: improved name spaces: ambiguous output is qualified; support
  1658 for hiding of names;
  1659 
  1660 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1661 XSYMBOL_HOME; no longer need to do manual configuration in most
  1662 situations;
  1663 
  1664 * system: compression of ML heaps images may now be controlled via -c
  1665 option of isabelle and isatool usedir (currently only observed by
  1666 Poly/ML);
  1667 
  1668 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1669 useful for remote X11);
  1670 
  1671 * system: provide TAGS file for Isabelle sources;
  1672 
  1673 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1674 order;
  1675 
  1676 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1677 timing flag supersedes proof_timing and Toplevel.trace;
  1678 
  1679 * ML: new combinators |>> and |>>> for incremental transformations
  1680 with secondary results (e.g. certain theory extensions):
  1681 
  1682 * ML: PureThy.add_defs gets additional argument to indicate potential
  1683 overloading (usually false);
  1684 
  1685 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1686 results;
  1687 
  1688 
  1689 
  1690 New in Isabelle99 (October 1999)
  1691 --------------------------------
  1692 
  1693 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1694 
  1695 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1696 are no longer simplified.  (This allows the simplifier to unfold recursive
  1697 functional programs.)  To restore the old behaviour, declare
  1698 
  1699     Delcongs [if_weak_cong];
  1700 
  1701 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1702 complement;
  1703 
  1704 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1705 
  1706 * HOL/datatype: mutual_induct_tac no longer exists --
  1707   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1708 
  1709 * HOL/typedef: fixed type inference for representing set; type
  1710 arguments now have to occur explicitly on the rhs as type constraints;
  1711 
  1712 * ZF: The con_defs part of an inductive definition may no longer refer
  1713 to constants declared in the same theory;
  1714 
  1715 * HOL, ZF: the function mk_cases, generated by the inductive
  1716 definition package, has lost an argument.  To simplify its result, it
  1717 uses the default simpset instead of a supplied list of theorems.
  1718 
  1719 * HOL/List: the constructors of type list are now Nil and Cons;
  1720 
  1721 * Simplifier: the type of the infix ML functions
  1722         setSSolver addSSolver setSolver addSolver
  1723 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1724 for packaging solvers. A solver is created via
  1725         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1726 where the string argument is only a comment.
  1727 
  1728 
  1729 *** Proof tools ***
  1730 
  1731 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1732 decision procedure for linear arithmetic. Currently it is used for
  1733 types `nat', `int', and `real' in HOL (see below); it can, should and
  1734 will be instantiated for other types and logics as well.
  1735 
  1736 * The simplifier now accepts rewrite rules with flexible heads, eg
  1737      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1738   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1739   matching.
  1740 
  1741 
  1742 *** General ***
  1743 
  1744 * New Isabelle/Isar subsystem provides an alternative to traditional
  1745 tactical theorem proving; together with the ProofGeneral/isar user
  1746 interface it offers an interactive environment for developing human
  1747 readable proof documents (Isar == Intelligible semi-automated
  1748 reasoning); for further information see isatool doc isar-ref,
  1749 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1750 
  1751 * improved and simplified presentation of theories: better HTML markup
  1752 (including colors), graph views in several sizes; isatool usedir now
  1753 provides a proper interface for user theories (via -P option); actual
  1754 document preparation based on (PDF)LaTeX is available as well (for
  1755 new-style theories only); see isatool doc system for more information;
  1756 
  1757 * native support for Proof General, both for classic Isabelle and
  1758 Isabelle/Isar;
  1759 
  1760 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1761 using the graph browser tool;
  1762 
  1763 * Isabelle manuals now also available as PDF;
  1764 
  1765 * theory loader rewritten from scratch (may not be fully
  1766 bug-compatible); old loadpath variable has been replaced by show_path,
  1767 add_path, del_path, reset_path functions; new operations such as
  1768 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1769 isatool doc ref);
  1770 
  1771 * improved isatool install: option -k creates KDE application icon,
  1772 option -p DIR installs standalone binaries;
  1773 
  1774 * added ML_PLATFORM setting (useful for cross-platform installations);
  1775 more robust handling of platform specific ML images for SML/NJ;
  1776 
  1777 * the settings environment is now statically scoped, i.e. it is never
  1778 created again in sub-processes invoked from isabelle, isatool, or
  1779 Isabelle;
  1780 
  1781 * path element specification '~~' refers to '$ISABELLE_HOME';
  1782 
  1783 * in locales, the "assumes" and "defines" parts may be omitted if
  1784 empty;
  1785 
  1786 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1787 long arrows);
  1788 
  1789 * new print_mode "HTML";
  1790 
  1791 * new flag show_tags controls display of tags of theorems (which are
  1792 basically just comments that may be attached by some tools);
  1793 
  1794 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1795 mode and goal output format:
  1796 
  1797 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1798 244c244
  1799 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1800 ---
  1801 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1802 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1803 181c181
  1804 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1805 ---
  1806 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1807 
  1808 * function bind_thms stores lists of theorems (cf. bind_thm);
  1809 
  1810 * new shorthand tactics ftac, eatac, datac, fatac;
  1811 
  1812 * qed (and friends) now accept "" as result name; in that case the
  1813 theorem is not stored, but proper checks and presentation of the
  1814 result still apply;
  1815 
  1816 * theorem database now also indexes constants "Trueprop", "all",
  1817 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1818 
  1819 
  1820 *** HOL ***
  1821 
  1822 ** HOL arithmetic **
  1823 
  1824 * There are now decision procedures for linear arithmetic over nat and
  1825 int:
  1826 
  1827 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1828 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1829 are treated as atomic; subformulae not involving type `nat' or `int'
  1830 are ignored; quantified subformulae are ignored unless they are
  1831 positive universal or negative existential. The tactic has to be
  1832 invoked by hand and can be a little bit slow. In particular, the
  1833 running time is exponential in the number of occurrences of `min' and
  1834 `max', and `-' on `nat'.
  1835 
  1836 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1837 (negated) (in)equalities among the premises and the conclusion into
  1838 account (i.e. no compound formulae) and does not know about `min' and
  1839 `max', and `-' on `nat'. It is fast and is used automatically by the
  1840 simplifier.
  1841 
  1842 NB: At the moment, these decision procedures do not cope with mixed
  1843 nat/int formulae where the two parts interact, such as `m < n ==>
  1844 int(m) < int(n)'.
  1845 
  1846 * HOL/Numeral provides a generic theory of numerals (encoded
  1847 efficiently as bit strings); setup for types nat/int/real is in place;
  1848 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1849 int, existing theories and proof scripts may require a few additional
  1850 type constraints;
  1851 
  1852 * integer division and remainder can now be performed on constant
  1853 arguments;
  1854 
  1855 * many properties of integer multiplication, division and remainder
  1856 are now available;
  1857 
  1858 * An interface to the Stanford Validity Checker (SVC) is available through the
  1859 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1860 are proved automatically.  SVC must be installed separately, and its results
  1861 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1862 invocation of the underlying oracle).  For SVC see
  1863   http://verify.stanford.edu/SVC
  1864 
  1865 * IsaMakefile: the HOL-Real target now builds an actual image;
  1866 
  1867 
  1868 ** HOL misc **
  1869 
  1870 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1871 (in Isabelle/Isar) -- by Gertrud Bauer;
  1872 
  1873 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1874 analysis for assembly languages with subtypes;
  1875 
  1876 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1877 -- avoids syntactic ambiguities and treats state, transition, and
  1878 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1879 changed syntax and (many) tactics;
  1880 
  1881 * HOL/inductive: Now also handles more general introduction rules such
  1882   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1883   theorems are now maintained within the theory (maintained via the
  1884   "mono" attribute);
  1885 
  1886 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1887   (using function types) such as
  1888 
  1889   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1890 
  1891 * HOL/record: record_simproc (part of the default simpset) takes care
  1892 of selectors applied to updated records; record_split_tac is no longer
  1893 part of the default claset; update_defs may now be removed from the
  1894 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1895 
  1896   claset_ref () := claset() addSWrapper record_split_wrapper;
  1897   Delsimprocs [record_simproc]
  1898 
  1899 * HOL/typedef: fixed type inference for representing set; type
  1900 arguments now have to occur explicitly on the rhs as type constraints;
  1901 
  1902 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1903 names rather than an ML expression;
  1904 
  1905 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1906 supplied later.  Program schemes can be defined, such as
  1907     "While B C s = (if B s then While B C (C s) else s)"
  1908 where the well-founded relation can be chosen after B and C have been given.
  1909 
  1910 * HOL/List: the constructors of type list are now Nil and Cons;
  1911 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1912 course, ML tools referring to List.list.op # etc. have to be adapted;
  1913 
  1914 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1915 disabled by default; run isabelle with option -m HOL to get back to
  1916 the original Gordon/HOL-style output;
  1917 
  1918 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1919 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1920 
  1921 * HOL basic syntax simplified (more orthogonal): all variants of
  1922 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1923 Eps operator is provided as well: "SOME x. P[x]";
  1924 
  1925 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1926 
  1927 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1928 thus available for user theories;
  1929 
  1930 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1931 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1932 time;
  1933 
  1934 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1935 several times and then mp;
  1936 
  1937 
  1938 *** LK ***
  1939 
  1940 * the notation <<...>> is now available as a notation for sequences of
  1941 formulas;
  1942 
  1943 * the simplifier is now installed
  1944 
  1945 * the axiom system has been generalized (thanks to Soren Heilmann)
  1946 
  1947 * the classical reasoner now has a default rule database
  1948 
  1949 
  1950 *** ZF ***
  1951 
  1952 * new primrec section allows primitive recursive functions to be given
  1953 directly (as in HOL) over datatypes and the natural numbers;
  1954 
  1955 * new tactics induct_tac and exhaust_tac for induction (or case
  1956 analysis) over datatypes and the natural numbers;
  1957 
  1958 * the datatype declaration of type T now defines the recursor T_rec;
  1959 
  1960 * simplification automatically does freeness reasoning for datatype
  1961 constructors;
  1962 
  1963 * automatic type-inference, with AddTCs command to insert new
  1964 type-checking rules;
  1965 
  1966 * datatype introduction rules are now added as Safe Introduction rules
  1967 to the claset;
  1968 
  1969 * the syntax "if P then x else y" is now available in addition to
  1970 if(P,x,y);
  1971 
  1972 
  1973 *** Internal programming interfaces ***
  1974 
  1975 * tuned simplifier trace output; new flag debug_simp;
  1976 
  1977 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1978 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1979 
  1980 * AxClass.axclass_tac lost the theory argument;
  1981 
  1982 * tuned current_goals_markers semantics: begin / end goal avoids
  1983 printing empty lines;
  1984 
  1985 * removed prs and prs_fn hook, which was broken because it did not
  1986 include \n in its semantics, forcing writeln to add one
  1987 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1988 string -> unit if you really want to output text without newline;
  1989 
  1990 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1991 plain output, interface builders may have to enable 'isabelle_font'
  1992 mode to get Isabelle font glyphs as before;
  1993 
  1994 * refined token_translation interface; INCOMPATIBILITY: output length
  1995 now of type real instead of int;
  1996 
  1997 * theory loader actions may be traced via new ThyInfo.add_hook
  1998 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1999 your own database of information attached to *whole* theories -- as
  2000 opposed to intra-theory data slots offered via TheoryDataFun;
  2001 
  2002 * proper handling of dangling sort hypotheses (at last!);
  2003 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2004 extra sort hypotheses that can be witnessed from the type signature;
  2005 the force_strip_shyps flag is gone, any remaining shyps are simply
  2006 left in the theorem (with a warning issued by strip_shyps_warning);
  2007 
  2008 
  2009 
  2010 New in Isabelle98-1 (October 1998)
  2011 ----------------------------------
  2012 
  2013 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2014 
  2015 * several changes of automated proof tools;
  2016 
  2017 * HOL: major changes to the inductive and datatype packages, including
  2018 some minor incompatibilities of theory syntax;
  2019 
  2020 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2021 called `inj_on';
  2022 
  2023 * HOL: removed duplicate thms in Arith:
  2024   less_imp_add_less  should be replaced by  trans_less_add1
  2025   le_imp_add_le      should be replaced by  trans_le_add1
  2026 
  2027 * HOL: unary minus is now overloaded (new type constraints may be
  2028 required);
  2029 
  2030 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2031 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2032 now taken as an integer constant.
  2033 
  2034 * Pure: ML function 'theory_of' renamed to 'theory';
  2035 
  2036 
  2037 *** Proof tools ***
  2038 
  2039 * Simplifier:
  2040   1. Asm_full_simp_tac is now more aggressive.
  2041      1. It will sometimes reorient premises if that increases their power to
  2042         simplify.
  2043      2. It does no longer proceed strictly from left to right but may also
  2044         rotate premises to achieve further simplification.
  2045      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2046      old Asm_full_simp_tac in that it does not rotate premises.
  2047   2. The simplifier now knows a little bit about nat-arithmetic.
  2048 
  2049 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2050 allows for selected deletion of wrappers, by introduction of names for
  2051 wrapper functionals.  This implies that addbefore, addSbefore,
  2052 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2053 and that adding two tactics with the same name overwrites the first
  2054 one (emitting a warning).
  2055   type wrapper = (int -> tactic) -> (int -> tactic)
  2056   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2057   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2058   delWrapper, delSWrapper: claset *  string            -> claset
  2059   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2060 
  2061 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2062 semantics; addbefore now affects only the unsafe part of step_tac
  2063 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2064 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2065 by Force_tac;
  2066 
  2067 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2068 compWrapper; added safe wrapper (and access functions for it);
  2069 
  2070 * HOL/split_all_tac is now much faster and fails if there is nothing
  2071 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2072 and the names of the automatically generated variables have changed.
  2073 split_all_tac has moved within claset() from unsafe wrappers to safe
  2074 wrappers, which means that !!-bound variables are split much more
  2075 aggressively, and safe_tac and clarify_tac now split such variables.
  2076 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2077 Note: the same holds for record_split_tac, which does the job of
  2078 split_all_tac for record fields.
  2079 
  2080 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2081 permanently to the default simpset using Addsplits just like
  2082 Addsimps. They can be removed via Delsplits just like
  2083 Delsimps. Lower-case versions are also available.
  2084 
  2085 * HOL/Simplifier: The rule split_if is now part of the default
  2086 simpset. This means that the simplifier will eliminate all occurrences
  2087 of if-then-else in the conclusion of a goal. To prevent this, you can
  2088 either remove split_if completely from the default simpset by
  2089 `Delsplits [split_if]' or remove it in a specific call of the
  2090 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2091 other case splitting rules to/from the default simpset: every datatype
  2092 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2093 t is the name of the datatype).
  2094 
  2095 * Classical reasoner / Simplifier combination: new force_tac (and
  2096 derivatives Force_tac, force) combines rewriting and classical
  2097 reasoning (and whatever other tools) similarly to auto_tac, but is
  2098 aimed to solve the given subgoal completely.
  2099 
  2100 
  2101 *** General ***
  2102 
  2103 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2104 and `goalw': the theory is no longer needed as an explicit argument -
  2105 the current theory context is used; assumptions are no longer returned
  2106 at the ML-level unless one of them starts with ==> or !!; it is
  2107 recommended to convert to these new commands using isatool fixgoal
  2108 (backup your sources first!);
  2109 
  2110 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2111 the current theory context, and 'theory' to lookup stored theories;
  2112 
  2113 * new theory section 'locale' for declaring constants, assumptions and
  2114 definitions that have local scope;
  2115 
  2116 * new theory section 'nonterminals' for purely syntactic types;
  2117 
  2118 * new theory section 'setup' for generic ML setup functions
  2119 (e.g. package initialization);
  2120 
  2121 * the distribution now includes Isabelle icons: see
  2122 lib/logo/isabelle-{small,tiny}.xpm;
  2123 
  2124 * isatool install - install binaries with absolute references to
  2125 ISABELLE_HOME/bin;
  2126 
  2127 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2128 
  2129 * print mode 'emacs' reserved for Isamode;
  2130 
  2131 * support multiple print (ast) translations per constant name;
  2132 
  2133 * theorems involving oracles are now printed with a suffixed [!];
  2134 
  2135 
  2136 *** HOL ***
  2137 
  2138 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2139 
  2140 * HOL/inductive package reorganized and improved: now supports mutual
  2141 definitions such as
  2142 
  2143   inductive EVEN ODD
  2144     intrs
  2145       null "0 : EVEN"
  2146       oddI "n : EVEN ==> Suc n : ODD"
  2147       evenI "n : ODD ==> Suc n : EVEN"
  2148 
  2149 new theorem list "elims" contains an elimination rule for each of the
  2150 recursive sets; inductive definitions now handle disjunctive premises
  2151 correctly (also ZF);
  2152 
  2153 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2154 "mutual_induct" no longer exists - the induction rule is always
  2155 contained in "induct";
  2156 
  2157 
  2158 * HOL/datatype package re-implemented and greatly improved: now
  2159 supports mutually recursive datatypes such as
  2160 
  2161   datatype
  2162     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2163             | SUM ('a aexp) ('a aexp)
  2164             | DIFF ('a aexp) ('a aexp)
  2165             | NUM 'a
  2166   and
  2167     'a bexp = LESS ('a aexp) ('a aexp)
  2168             | AND ('a bexp) ('a bexp)
  2169             | OR ('a bexp) ('a bexp)
  2170 
  2171 as well as indirectly recursive datatypes such as
  2172 
  2173   datatype
  2174     ('a, 'b) term = Var 'a
  2175                   | App 'b ((('a, 'b) term) list)
  2176 
  2177 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2178 induction on mutually / indirectly recursive datatypes.
  2179 
  2180 Primrec equations are now stored in theory and can be accessed via
  2181 <function_name>.simps.
  2182 
  2183 INCOMPATIBILITIES:
  2184 
  2185   - Theories using datatypes must now have theory Datatype as an
  2186     ancestor.
  2187   - The specific <typename>.induct_tac no longer exists - use the
  2188     generic induct_tac instead.
  2189   - natE has been renamed to nat.exhaust - use exhaust_tac
  2190     instead of res_inst_tac ... natE. Note that the variable
  2191     names in nat.exhaust differ from the names in natE, this
  2192     may cause some "fragile" proofs to fail.
  2193   - The theorems split_<typename>_case and split_<typename>_case_asm
  2194     have been renamed to <typename>.split and <typename>.split_asm.
  2195   - Since default sorts of type variables are now handled correctly,
  2196     some datatype definitions may have to be annotated with explicit
  2197     sort constraints.
  2198   - Primrec definitions no longer require function name and type
  2199     of recursive argument.
  2200 
  2201 Consider using isatool fixdatatype to adapt your theories and proof
  2202 scripts to the new package (backup your sources first!).
  2203 
  2204 
  2205 * HOL/record package: considerably improved implementation; now
  2206 includes concrete syntax for record types, terms, updates; theorems
  2207 for surjective pairing and splitting !!-bound record variables; proof
  2208 support is as follows:
  2209 
  2210   1) standard conversions (selectors or updates applied to record
  2211 constructor terms) are part of the standard simpset;
  2212 
  2213   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2214 made part of standard simpset and claset via addIffs;
  2215 
  2216   3) a tactic for record field splitting (record_split_tac) is part of
  2217 the standard claset (addSWrapper);
  2218 
  2219 To get a better idea about these rules you may retrieve them via
  2220 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2221 the name of your record type.
  2222 
  2223 The split tactic 3) conceptually simplifies by the following rule:
  2224 
  2225   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2226 
  2227 Thus any record variable that is bound by meta-all will automatically
  2228 blow up into some record constructor term, consequently the
  2229 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2230 solve record problems automatically.
  2231 
  2232 
  2233 * reorganized the main HOL image: HOL/Integ and String loaded by
  2234 default; theory Main includes everything;
  2235 
  2236 * automatic simplification of integer sums and comparisons, using cancellation;
  2237 
  2238 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2239 
  2240 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2241 
  2242 * many new identities for unions, intersections, set difference, etc.;
  2243 
  2244 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2245 called split_if, split_split, split_sum_case and split_nat_case (to go
  2246 with add/delsplits);
  2247 
  2248 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2249 (?x::unit) = (); this is made part of the default simpset, which COULD
  2250 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2251 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2252 unit_abs_eta_conv is added in order to counter the effect of
  2253 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2254 %u.f();
  2255 
  2256 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2257 makes more sense);
  2258 
  2259 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2260   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2261   disjointness reasoning but breaking a few old proofs.
  2262 
  2263 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2264 to 'converse' from 'inverse' (for compatibility with ZF and some
  2265 literature);
  2266 
  2267 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2268 the well-founded relation;
  2269 
  2270 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2271     Compl A.  The "Compl" syntax remains available as input syntax for this
  2272     release ONLY.
  2273 
  2274 * HOL/Update: new theory of function updates:
  2275     f(a:=b) == %x. if x=a then b else f x
  2276 may also be iterated as in f(a:=b,c:=d,...);
  2277 
  2278 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2279 
  2280 * HOL/List:
  2281   - new function list_update written xs[i:=v] that updates the i-th
  2282     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2283   - new function `upt' written [i..j(] which generates the list
  2284     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2285     bound write [i..j], which is a shorthand for [i..j+1(].
  2286   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2287 
  2288 * HOL/Arith:
  2289   - removed 'pred' (predecessor) function;
  2290   - generalized some theorems about n-1;
  2291   - many new laws about "div" and "mod";
  2292   - new laws about greatest common divisors (see theory ex/Primes);
  2293 
  2294 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2295 instead of "inverse";
  2296 
  2297 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2298   of the multiset ordering;
  2299 
  2300 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2301   (not included by default);
  2302 
  2303 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2304 
  2305 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2306   programs, i.e. different program variables may have different types.
  2307 
  2308 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2309   [previously, this check worked only if the rewrite rule was unconditional]
  2310   Now rew can involve either definitions or equalities (either == or =).
  2311 
  2312 
  2313 *** ZF ***
  2314 
  2315 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2316   only the theorems proved on ZF.ML;
  2317 
  2318 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2319   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2320   disjointness reasoning but breaking a few old proofs.
  2321 
  2322 * ZF/Update: new theory of function updates
  2323     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2324   may also be iterated as in f(a:=b,c:=d,...);
  2325 
  2326 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2327 
  2328 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2329   [previously, this check worked only if the rewrite rule was unconditional]
  2330   Now rew can involve either definitions or equalities (either == or =).
  2331 
  2332 * case_tac provided for compatibility with HOL
  2333     (like the old excluded_middle_tac, but with subgoals swapped)
  2334 
  2335 
  2336 *** Internal programming interfaces ***
  2337 
  2338 * Pure: several new basic modules made available for general use, see
  2339 also src/Pure/README;
  2340 
  2341 * improved the theory data mechanism to support encapsulation (data
  2342 kind name replaced by private Object.kind, acting as authorization
  2343 key); new type-safe user interface via functor TheoryDataFun; generic
  2344 print_data function becomes basically useless;
  2345 
  2346 * removed global_names compatibility flag -- all theory declarations
  2347 are qualified by default;
  2348 
  2349 * module Pure/Syntax now offers quote / antiquote translation
  2350 functions (useful for Hoare logic etc. with implicit dependencies);
  2351 see HOL/ex/Antiquote for an example use;
  2352 
  2353 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2354 cterm -> thm;
  2355 
  2356 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2357 subgoal;
  2358 
  2359 * Display.print_goals function moved to Locale.print_goals;
  2360 
  2361 * standard print function for goals supports current_goals_markers
  2362 variable for marking begin of proof, end of proof, start of goal; the
  2363 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2364 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2365 for example;
  2366 
  2367 
  2368 
  2369 New in Isabelle98 (January 1998)
  2370 --------------------------------
  2371 
  2372 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2373 
  2374 * changed lexical syntax of terms / types: dots made part of long
  2375 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2376 
  2377 * simpset (and claset) reference variable replaced by functions
  2378 simpset / simpset_ref;
  2379 
  2380 * no longer supports theory aliases (via merge) and non-trivial
  2381 implicit merge of thms' signatures;
  2382 
  2383 * most internal names of constants changed due to qualified names;
  2384 
  2385 * changed Pure/Sequence interface (see Pure/seq.ML);
  2386 
  2387 
  2388 *** General Changes ***
  2389 
  2390 * hierachically structured name spaces (for consts, types, axms, thms
  2391 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2392 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2393 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2394 long_names for fully qualified output names; NOTE: ML programs
  2395 (special tactics, packages etc.) referring to internal names may have
  2396 to be adapted to cope with fully qualified names; in case of severe
  2397 backward campatibility problems try setting 'global_names' at compile
  2398 time to have enrything declared within a flat name space; one may also
  2399 fine tune name declarations in theories via the 'global' and 'local'
  2400 section;
  2401 
  2402 * reimplemented the implicit simpset and claset using the new anytype
  2403 data filed in signatures; references simpset:simpset ref etc. are
  2404 replaced by functions simpset:unit->simpset and
  2405 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2406 to patch your ML files accordingly;
  2407 
  2408 * HTML output now includes theory graph data for display with Java
  2409 applet or isatool browser; data generated automatically via isatool
  2410 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2411 
  2412 * defs may now be conditional; improved rewrite_goals_tac to handle
  2413 conditional equations;
  2414 
  2415 * defs now admits additional type arguments, using TYPE('a) syntax;
  2416 
  2417 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2418 creates a new theory node; implicit merge of thms' signatures is
  2419 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2420 transfer:theory->thm->thm in (rare) cases;
  2421 
  2422 * improved handling of draft signatures / theories; draft thms (and
  2423 ctyps, cterms) are automatically promoted to real ones;
  2424 
  2425 * slightly changed interfaces for oracles: admit many per theory, named
  2426 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2427 
  2428 * print_goals: optional output of const types (set show_consts and
  2429 show_types);
  2430 
  2431 * improved output of warnings (###) and errors (***);
  2432 
  2433 * subgoal_tac displays a warning if the new subgoal has type variables;
  2434 
  2435 * removed old README and Makefiles;
  2436 
  2437 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2438 
  2439 * removed obsolete init_pps and init_database;
  2440 
  2441 * deleted the obsolete tactical STATE, which was declared by
  2442     fun STATE tacfun st = tacfun st st;
  2443 
  2444 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2445 (which abbreviates $HOME);
  2446 
  2447 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2448 use isatool fixseq to adapt your ML programs (this works for fully
  2449 qualified references to the Sequence structure only!);
  2450 
  2451 * use_thy no longer requires writable current directory; it always
  2452 reloads .ML *and* .thy file, if either one is out of date;
  2453 
  2454 
  2455 *** Classical Reasoner ***
  2456 
  2457 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2458 tactics that use classical reasoning to simplify a subgoal without
  2459 splitting it into several subgoals;
  2460 
  2461 * Safe_tac: like safe_tac but uses the default claset;
  2462 
  2463 
  2464 *** Simplifier ***
  2465 
  2466 * added simplification meta rules:
  2467     (asm_)(full_)simplify: simpset -> thm -> thm;
  2468 
  2469 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2470 logics (again);
  2471 
  2472 * added prems argument to simplification procedures;
  2473 
  2474 * HOL, FOL, ZF: added infix function `addsplits':
  2475   instead of `<simpset> setloop (split_tac <thms>)'
  2476   you can simply write `<simpset> addsplits <thms>'
  2477 
  2478 
  2479 *** Syntax ***
  2480 
  2481 * TYPE('a) syntax for type reflection terms;
  2482 
  2483 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2484 
  2485 * pretty printer: changed order of mixfix annotation preference (again!);
  2486 
  2487 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2488 
  2489 
  2490 *** HOL ***
  2491 
  2492 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2493   with `addloop' of the simplifier to faciliate case splitting in premises.
  2494 
  2495 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2496 
  2497 * HOL/Auth: new protocol proofs including some for the Internet
  2498   protocol TLS;
  2499 
  2500 * HOL/Map: new theory of `maps' a la VDM;
  2501 
  2502 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2503 cancelling out common nat summands from =, <, <= (in)equalities, or
  2504 differences; simplification procedures nat_cancel_factor for
  2505 cancelling common factor from =, <, <= (in)equalities over natural
  2506 sums; nat_cancel contains both kinds of procedures, it is installed by
  2507 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2508 
  2509 * HOL/simplifier: terms of the form
  2510   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2511   are rewritten to
  2512   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2513   and those of the form
  2514   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2515   are rewritten to
  2516   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2517 
  2518 * HOL/datatype
  2519   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2520 
  2521   P(t_case f1 ... fn x) =
  2522      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2523         ...
  2524        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2525      )
  2526 
  2527   and a theorem `split_t_case_asm' of the form
  2528 
  2529   P(t_case f1 ... fn x) =
  2530     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2531         ...
  2532        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2533      )
  2534   which can be added to a simpset via `addsplits'. The existing theorems
  2535   expand_list_case and expand_option_case have been renamed to
  2536   split_list_case and split_option_case.
  2537 
  2538 * HOL/Arithmetic:
  2539   - `pred n' is automatically converted to `n-1'.
  2540     Users are strongly encouraged not to use `pred' any longer,
  2541     because it will disappear altogether at some point.
  2542   - Users are strongly encouraged to write "0 < n" rather than
  2543     "n ~= 0". Theorems and proof tools have been modified towards this
  2544     `standard'.
  2545 
  2546 * HOL/Lists:
  2547   the function "set_of_list" has been renamed "set" (and its theorems too);
  2548   the function "nth" now takes its arguments in the reverse order and
  2549   has acquired the infix notation "!" as in "xs!n".
  2550 
  2551 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2552 
  2553 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2554   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2555 
  2556 * HOL/record: extensible records with schematic structural subtyping
  2557 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2558 still lacks various theorems and concrete record syntax;
  2559 
  2560 
  2561 *** HOLCF ***
  2562 
  2563 * removed "axioms" and "generated by" sections;
  2564 
  2565 * replaced "ops" section by extended "consts" section, which is capable of
  2566   handling the continuous function space "->" directly;
  2567 
  2568 * domain package:
  2569   . proves theorems immediately and stores them in the theory,
  2570   . creates hierachical name space,
  2571   . now uses normal mixfix annotations (instead of cinfix...),
  2572   . minor changes to some names and values (for consistency),
  2573   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2574   . separator between mutual domain defs: changed "," to "and",
  2575   . improved handling of sort constraints;  now they have to
  2576     appear on the left-hand side of the equations only;
  2577 
  2578 * fixed LAM <x,y,zs>.b syntax;
  2579 
  2580 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2581 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2582 
  2583 
  2584 *** FOL and ZF ***
  2585 
  2586 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2587   with `addloop' of the simplifier to faciliate case splitting in premises.
  2588 
  2589 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2590 in HOL, they strip ALL and --> from proved theorems;
  2591 
  2592 
  2593 
  2594 New in Isabelle94-8 (May 1997)
  2595 ------------------------------
  2596 
  2597 *** General Changes ***
  2598 
  2599 * new utilities to build / run / maintain Isabelle etc. (in parts
  2600 still somewhat experimental); old Makefiles etc. still functional;
  2601 
  2602 * new 'Isabelle System Manual';
  2603 
  2604 * INSTALL text, together with ./configure and ./build scripts;
  2605 
  2606 * reimplemented type inference for greater efficiency, better error
  2607 messages and clean internal interface;
  2608 
  2609 * prlim command for dealing with lots of subgoals (an easier way of
  2610 setting goals_limit);
  2611 
  2612 
  2613 *** Syntax ***
  2614 
  2615 * supports alternative (named) syntax tables (parser and pretty
  2616 printer); internal interface is provided by add_modesyntax(_i);
  2617 
  2618 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2619 be used in conjunction with the Isabelle symbol font; uses the
  2620 "symbols" syntax table;
  2621 
  2622 * added token_translation interface (may translate name tokens in
  2623 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2624 the current print_mode); IMPORTANT: user print translation functions
  2625 are responsible for marking newly introduced bounds
  2626 (Syntax.mark_boundT);
  2627 
  2628 * token translations for modes "xterm" and "xterm_color" that display
  2629 names in bold, underline etc. or colors (which requires a color
  2630 version of xterm);
  2631 
  2632 * infixes may now be declared with names independent of their syntax;
  2633 
  2634 * added typed_print_translation (like print_translation, but may
  2635 access type of constant);
  2636 
  2637 
  2638 *** Classical Reasoner ***
  2639 
  2640 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2641 some limitations.  Blast_tac...
  2642   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2643   + ignores elimination rules that don't have the correct format
  2644         (the conclusion MUST be a formula variable)
  2645   + ignores types, which can make HOL proofs fail
  2646   + rules must not require higher-order unification, e.g. apply_type in ZF
  2647     [message "Function Var's argument not a bound variable" relates to this]
  2648   + its proof strategy is more general but can actually be slower
  2649 
  2650 * substitution with equality assumptions no longer permutes other
  2651 assumptions;
  2652 
  2653 * minor changes in semantics of addafter (now called addaltern); renamed
  2654 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2655 (and access functions for it);
  2656 
  2657 * improved combination of classical reasoner and simplifier:
  2658   + functions for handling clasimpsets
  2659   + improvement of addss: now the simplifier is called _after_ the
  2660     safe steps.
  2661   + safe variant of addss called addSss: uses safe simplifications
  2662     _during_ the safe steps. It is more complete as it allows multiple
  2663     instantiations of unknowns (e.g. with slow_tac).
  2664 
  2665 *** Simplifier ***
  2666 
  2667 * added interface for simplification procedures (functions that
  2668 produce *proven* rewrite rules on the fly, depending on current
  2669 redex);
  2670 
  2671 * ordering on terms as parameter (used for ordered rewriting);
  2672 
  2673 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2674 
  2675 * the solver is now split into a safe and an unsafe part.
  2676 This should be invisible for the normal user, except that the
  2677 functions setsolver and addsolver have been renamed to setSolver and
  2678 addSolver; added safe_asm_full_simp_tac;
  2679 
  2680 
  2681 *** HOL ***
  2682 
  2683 * a generic induction tactic `induct_tac' which works for all datatypes and
  2684 also for type `nat';
  2685 
  2686 * a generic case distinction tactic `exhaust_tac' which works for all
  2687 datatypes and also for type `nat';
  2688 
  2689 * each datatype comes with a function `size';
  2690 
  2691 * patterns in case expressions allow tuple patterns as arguments to
  2692 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2693 
  2694 * primrec now also works with type nat;
  2695 
  2696 * recdef: a new declaration form, allows general recursive functions to be
  2697 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2698 
  2699 * the constant for negation has been renamed from "not" to "Not" to
  2700 harmonize with FOL, ZF, LK, etc.;
  2701 
  2702 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2703 infinite lists;
  2704 
  2705 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2706 
  2707 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2708 problems in commutative rings, using axiomatic type classes for + and *;
  2709 
  2710 * more examples in HOL/MiniML and HOL/Auth;
  2711 
  2712 * more default rewrite rules for quantifiers, union/intersection;
  2713 
  2714 * a new constant `arbitrary == @x.False';
  2715 
  2716 * HOLCF/IOA replaces old HOL/IOA;
  2717 
  2718 * HOLCF changes: derived all rules and arities
  2719   + axiomatic type classes instead of classes
  2720   + typedef instead of faking type definitions
  2721   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2722   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2723   + eliminated the types void, one, tr
  2724   + use unit lift and bool lift (with translations) instead of one and tr
  2725   + eliminated blift from Lift3.thy (use Def instead of blift)
  2726   all eliminated rules are derived as theorems --> no visible changes ;
  2727 
  2728 
  2729 *** ZF ***
  2730 
  2731 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2732 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2733 as ZF_cs addSIs [equalityI];
  2734 
  2735 
  2736 
  2737 New in Isabelle94-7 (November 96)
  2738 ---------------------------------
  2739 
  2740 * allowing negative levels (as offsets) in prlev and choplev;
  2741 
  2742 * super-linear speedup for large simplifications;
  2743 
  2744 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2745 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2746 FAIL); can suppress it using the command Delsimps (ex_simps @
  2747 all_simps); De Morgan laws are also now included, by default;
  2748 
  2749 * improved printing of ==>  :  ~:
  2750 
  2751 * new object-logic "Sequents" adds linear logic, while replacing LK
  2752 and Modal (thanks to Sara Kalvala);
  2753 
  2754 * HOL/Auth: correctness proofs for authentication protocols;
  2755 
  2756 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2757 examples on HOL/Auth);
  2758 
  2759 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2760 the rewriter and classical reasoner simultaneously;
  2761 
  2762 * function uresult no longer returns theorems in "standard" format;
  2763 regain previous version by: val uresult = standard o uresult;
  2764 
  2765 
  2766 
  2767 New in Isabelle94-6
  2768 -------------------
  2769 
  2770 * oracles -- these establish an interface between Isabelle and trusted
  2771 external reasoners, which may deliver results as theorems;
  2772 
  2773 * proof objects (in particular record all uses of oracles);
  2774 
  2775 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2776 
  2777 * "constdefs" section in theory files;
  2778 
  2779 * "primrec" section (HOL) no longer requires names;
  2780 
  2781 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2782 
  2783 
  2784 
  2785 New in Isabelle94-5
  2786 -------------------
  2787 
  2788 * reduced space requirements;
  2789 
  2790 * automatic HTML generation from theories;
  2791 
  2792 * theory files no longer require "..." (quotes) around most types;
  2793 
  2794 * new examples, including two proofs of the Church-Rosser theorem;
  2795 
  2796 * non-curried (1994) version of HOL is no longer distributed;
  2797 
  2798 
  2799 
  2800 New in Isabelle94-4
  2801 -------------------
  2802 
  2803 * greatly reduced space requirements;
  2804 
  2805 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2806 
  2807 * searchable theorem database (see the section "Retrieving theorems" on
  2808 page 8 of the Reference Manual);
  2809 
  2810 * new examples, including Grabczewski's monumental case study of the
  2811 Axiom of Choice;
  2812 
  2813 * The previous version of HOL renamed to Old_HOL;
  2814 
  2815 * The new version of HOL (previously called CHOL) uses a curried syntax
  2816 for functions.  Application looks like f a b instead of f(a,b);
  2817 
  2818 * Mutually recursive inductive definitions finally work in HOL;
  2819 
  2820 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2821 translates to the operator "split";
  2822 
  2823 
  2824 
  2825 New in Isabelle94-3
  2826 -------------------
  2827 
  2828 * new infix operator, addss, allowing the classical reasoner to
  2829 perform simplification at each step of its search.  Example:
  2830         fast_tac (cs addss ss)
  2831 
  2832 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2833 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2834 look like (a,b) instead of <a,b>;
  2835 
  2836 * PLEASE NOTE: CHOL will eventually replace HOL!
  2837 
  2838 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2839 It translates to the operator "split".  A new theory of integers is available;
  2840 
  2841 * In ZF, integer numerals now denote two's-complement binary integers.
  2842 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2843 
  2844 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2845 of the Axiom of Choice;
  2846 
  2847 
  2848 
  2849 New in Isabelle94-2
  2850 -------------------
  2851 
  2852 * Significantly faster resolution;
  2853 
  2854 * the different sections in a .thy file can now be mixed and repeated
  2855 freely;
  2856 
  2857 * Database of theorems for FOL, HOL and ZF.  New
  2858 commands including qed, qed_goal and bind_thm store theorems in the database.
  2859 
  2860 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2861 a given theory (thms_of), or find out what theory a theorem was proved in
  2862 (theory_of_thm);
  2863 
  2864 * Bugs fixed in the inductive definition and datatype packages;
  2865 
  2866 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2867 and HOL_dup_cs obsolete;
  2868 
  2869 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2870 have been removed;
  2871 
  2872 * Simpler definition of function space in ZF;
  2873 
  2874 * new results about cardinal and ordinal arithmetic in ZF;
  2875 
  2876 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2877 types;
  2878 
  2879 
  2880 $Id$