NEWS
author nipkow
Thu Dec 09 18:30:59 2004 +0100 (2004-12-09)
changeset 15392 290bc97038c7
parent 15361 bb2dd95c8c5e
child 15406 75a2ca90693e
permissions -rw-r--r--
First step in reorganizing Finite_Set
     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: "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   196   Similarly for all quantifiers: "ALL x > y" etc.
   197   The x-symbol for >= is \<ge>.
   198 
   199 * HOL/SetInterval: The syntax for open intervals has changed:
   200 
   201   Old         New
   202   {..n(}   -> {..<n}
   203   {)n..}   -> {n<..}
   204   {m..n(}  -> {m..<n}
   205   {)m..n}  -> {m<..n}
   206   {)m..n(} -> {m<..<n}
   207 
   208   The old syntax is still supported but will disappear in the future.
   209   For conversion use the following emacs search and replace patterns:
   210 
   211   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   212   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   213 
   214   They are not perfect but work quite well.
   215 
   216 * HOL: The syntax for 'setsum', summation over finite sets, has changed:
   217 
   218   The syntax for 'setsum (%x. e) A' used to be '\<Sum>x:A. e'
   219   and is now either 'SUM x:A. e' or '\<Sum>x\<in>A. e'.
   220 
   221   There is new syntax for summation over finite sets:
   222 
   223   '\<Sum>x | P. e'    is the same as  'setsum (%x. e) {x. P}'
   224   '\<Sum>x=a..b. e'   is the same as  'setsum (%x. e) {a..b}'
   225   '\<Sum>x=a..<b. e'  is the same as  'setsum (%x. e) {a..<b}'
   226   '\<Sum>x<k. e'      is the same as  'setsum (%x. e) {..<k}'
   227 
   228   Function 'Summation' over nat is gone, its syntax '\<Sum>i<k. e'
   229   now translates into 'setsum' as above.
   230 
   231 * HOL: Finite set induction: In Isar proofs, the insert case is now
   232   "case (insert x F)" instead of the old counterintuitive "case (insert F x)".
   233 
   234 * HOL/Simplifier:
   235 
   236   - Is now set up to reason about transitivity chains involving "trancl"
   237   (r^+) and "rtrancl" (r^*) by setting up tactics provided by
   238   Provers/trancl.ML as additional solvers.  INCOMPATIBILITY: old proofs break
   239   occasionally as simplification may now solve more goals than previously.
   240 
   241   - Converts x <= y into x = y if assumption y <= x is present.  Works for
   242   all partial orders (class "order"), in particular numbers and sets. For
   243   linear orders (e.g. numbers) it treats ~ x < y just like y <= x.
   244 
   245 * HOL: new 'isatool dimacs2hol' to convert files in DIMACS CNF format
   246   (containing Boolean satisfiability problems) into Isabelle/HOL theories.
   247 
   248 
   249 *** HOLCF ***
   250 
   251 * HOLCF: discontinued special version of 'constdefs' (which used to
   252   support continuous functions) in favor of the general Pure one with
   253   full type-inference.
   254 
   255 
   256 *** ZF ***
   257 
   258 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the
   259   First Isomorphism Theorem (on quotienting by the kernel of a
   260   homomorphism).
   261 
   262 * ZF/Simplifier: install second copy of type solver that actually
   263   makes use of TC rules declared to Isar proof contexts (or locales);
   264   the old version is still required for ML proof scripts.
   265 
   266 
   267 
   268 New in Isabelle2004 (April 2004)
   269 --------------------------------
   270 
   271 *** General ***
   272 
   273 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   274   Replaces linorder.ML.
   275 
   276 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   277   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   278   (\<a>...\<z>), are now considered normal letters, and can therefore
   279   be used anywhere where an ASCII letter (a...zA...Z) has until
   280   now. COMPATIBILITY: This obviously changes the parsing of some
   281   terms, especially where a symbol has been used as a binder, say
   282   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   283   as an identifier.  Fix it by inserting a space around former
   284   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   285   existing theory and ML files.
   286 
   287 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   288 
   289 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   290   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   291   a normal (but invisible) letter. For multiple letter subscripts repeat
   292   \<^isub> like this: x\<^isub>1\<^isub>2.
   293 
   294 * Pure: There are now sub-/superscripts that can span more than one
   295   character. Text between \<^bsub> and \<^esub> is set in subscript in
   296   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   297   superscript. The new control characters are not identifier parts.
   298 
   299 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   300   content of "..." to the latex file instead of \isacntrl... . The "..."
   301   may consist of any printable characters excluding the end bracket >.
   302 
   303 * Pure: Using new Isar command "finalconsts" (or the ML functions
   304   Theory.add_finals or Theory.add_finals_i) it is now possible to
   305   declare constants "final", which prevents their being given a definition
   306   later.  It is useful for constants whose behaviour is fixed axiomatically
   307   rather than definitionally, such as the meta-logic connectives.
   308 
   309 * Pure: 'instance' now handles general arities with general sorts
   310   (i.e. intersections of classes),
   311 
   312 * Presentation: generated HTML now uses a CSS style sheet to make layout
   313   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   314   It can be changed to alter the colors/layout of generated pages.
   315 
   316 
   317 *** Isar ***
   318 
   319 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   320   cut_tac, subgoal_tac and thin_tac:
   321   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   322     locales are no longer forced to write Isar proof scripts.
   323     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   324     emulations.
   325   - INCOMPATIBILITY: names of variables to be instantiated may no
   326     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   327     This is consistent with the instantiation attribute "where".
   328 
   329 * Attributes "where" and "of":
   330   - Now take type variables of instantiated theorem into account when reading
   331     the instantiation string.  This fixes a bug that caused instantiated
   332     theorems to have too special types in some circumstances.
   333   - "where" permits explicit instantiations of type variables.
   334 
   335 * Calculation commands "moreover" and "also" no longer interfere with
   336   current facts ("this"), admitting arbitrary combinations with "then"
   337   and derived forms.
   338 
   339 * Locales:
   340   - Goal statements involving the context element "includes" no longer
   341     generate theorems with internal delta predicates (those ending on
   342     "_axioms") in the premise.
   343     Resolve particular premise with <locale>.intro to obtain old form.
   344   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   345     specification and "includes" elements in goal statement.
   346   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   347     [intro?] and [elim?] (respectively) by default.
   348   - Experimental command for instantiation of locales in proof contexts:
   349         instantiate <label>[<attrs>]: <loc>
   350     Instantiates locale <loc> and adds all its theorems to the current context
   351     taking into account their attributes.  Label and attrs are optional
   352     modifiers, like in theorem declarations.  If present, names of
   353     instantiated theorems are qualified with <label>, and the attributes
   354     <attrs> are applied after any attributes these theorems might have already.
   355       If the locale has assumptions, a chained fact of the form
   356     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   357     are derived.  The command does not support old-style locales declared
   358     with "locale (open)".
   359       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   360 
   361 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   362   (Isar) contexts.
   363 
   364 
   365 *** HOL ***
   366 
   367 * Proof import: new image HOL4 contains the imported library from
   368   the HOL4 system with about 2500 theorems. It is imported by
   369   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   370   can be used like any other Isabelle image.  See
   371   HOL/Import/HOL/README for more information.
   372 
   373 * Simplifier:
   374   - Much improved handling of linear and partial orders.
   375     Reasoners for linear and partial orders are set up for type classes
   376     "linorder" and "order" respectively, and are added to the default simpset
   377     as solvers.  This means that the simplifier can build transitivity chains
   378     to solve goals from the assumptions.
   379   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   380     of blast or auto after simplification become unnecessary because the goal
   381     is solved by simplification already.
   382 
   383 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   384     all proved in axiomatic type classes for semirings, rings and fields.
   385 
   386 * Numerics:
   387   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   388     now formalized using the Ring_and_Field theory mentioned above.
   389   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   390     than before, because now they are set up once in a generic manner.
   391   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   392     Look for the general versions in Ring_and_Field (and Power if they concern
   393     exponentiation).
   394 
   395 * Type "rat" of the rational numbers is now available in HOL-Complex.
   396 
   397 * Records:
   398   - Record types are now by default printed with their type abbreviation
   399     instead of the list of all field types. This can be configured via
   400     the reference "print_record_type_abbr".
   401   - Simproc "record_upd_simproc" for simplification of multiple updates added
   402     (not enabled by default).
   403   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   404     EX x. x = sel r to True (not enabled by default).
   405   - Tactic "record_split_simp_tac" to split and simplify records added.
   406 
   407 * 'specification' command added, allowing for definition by
   408   specification.  There is also an 'ax_specification' command that
   409   introduces the new constants axiomatically.
   410 
   411 * arith(_tac) is now able to generate counterexamples for reals as well.
   412 
   413 * HOL-Algebra: new locale "ring" for non-commutative rings.
   414 
   415 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   416   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   417 
   418 * HOL-Matrix: a first theory for matrices in HOL with an application of
   419   matrix theory to linear programming.
   420 
   421 * Unions and Intersections:
   422   The latex output syntax of UN and INT has been changed
   423   from "\Union x \in A. B" to "\Union_{x \in A} B"
   424   i.e. the index formulae has become a subscript.
   425   Similarly for "\Union x. B", and for \Inter instead of \Union.
   426 
   427 * Unions and Intersections over Intervals:
   428   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   429   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   430   like in normal math, and corresponding versions for < and for intersection.
   431 
   432 * ML: the legacy theory structures Int and List have been removed. They had
   433   conflicted with ML Basis Library structures having the same names.
   434 
   435 * 'refute' command added to search for (finite) countermodels.  Only works
   436   for a fragment of HOL.  The installation of an external SAT solver is
   437   highly recommended.  See "HOL/Refute.thy" for details.
   438 
   439 * 'quickcheck' command: Allows to find counterexamples by evaluating
   440   formulae under an assignment of free variables to random values.
   441   In contrast to 'refute', it can deal with inductive datatypes,
   442   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   443   for examples.
   444 
   445 
   446 *** HOLCF ***
   447 
   448 * Streams now come with concatenation and are part of the HOLCF image
   449 
   450 
   451 
   452 New in Isabelle2003 (May 2003)
   453 ------------------------------
   454 
   455 *** General ***
   456 
   457 * Provers/simplifier:
   458 
   459   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   460     Assumptions are now subject to complete mutual simplification,
   461     not just from left to right. The simplifier now preserves
   462     the order of assumptions.
   463 
   464     Potential INCOMPATIBILITY:
   465 
   466     -- simp sometimes diverges where the old version did
   467        not, e.g. invoking simp on the goal
   468 
   469         [| P (f x); y = x; f x = f y |] ==> Q
   470 
   471        now gives rise to the infinite reduction sequence
   472 
   473         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   474 
   475        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   476        kind of problem.
   477 
   478     -- Tactics combining classical reasoner and simplification (such as auto)
   479        are also affected by this change, because many of them rely on
   480        simp. They may sometimes diverge as well or yield a different numbers
   481        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   482        in case of problems. Sometimes subsequent calls to the classical
   483        reasoner will fail because a preceeding call to the simplifier too
   484        eagerly simplified the goal, e.g. deleted redundant premises.
   485 
   486   - The simplifier trace now shows the names of the applied rewrite rules
   487 
   488   - You can limit the number of recursive invocations of the simplifier
   489     during conditional rewriting (where the simplifie tries to solve the
   490     conditions before applying the rewrite rule):
   491     ML "simp_depth_limit := n"
   492     where n is an integer. Thus you can force termination where previously
   493     the simplifier would diverge.
   494 
   495   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   496 
   497   - No longer aborts on failed congruence proof.  Instead, the
   498     congruence is ignored.
   499 
   500 * Pure: New generic framework for extracting programs from constructive
   501   proofs. See HOL/Extraction.thy for an example instantiation, as well
   502   as HOL/Extraction for some case studies.
   503 
   504 * Pure: The main goal of the proof state is no longer shown by default, only
   505 the subgoals. This behaviour is controlled by a new flag.
   506    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   507 (ML: Proof.show_main_goal).
   508 
   509 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   510 rules whose conclusion matches subgoal 1:
   511       PG menu: Isabelle/Isar -> Show me -> matching rules
   512 The rules are ordered by how closely they match the subgoal.
   513 In particular, rules that solve a subgoal outright are displayed first
   514 (or rather last, the way they are printed).
   515 (ML: ProofGeneral.print_intros())
   516 
   517 * Pure: New flag trace_unify_fail causes unification to print
   518 diagnostic information (PG: in trace buffer) when it fails. This is
   519 useful for figuring out why single step proofs like rule, erule or
   520 assumption failed.
   521 
   522 * Pure: Locale specifications now produce predicate definitions
   523 according to the body of text (covering assumptions modulo local
   524 definitions); predicate "loc_axioms" covers newly introduced text,
   525 while "loc" is cumulative wrt. all included locale expressions; the
   526 latter view is presented only on export into the global theory
   527 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   528 on the old view without predicates;
   529 
   530 * Pure: predefined locales "var" and "struct" are useful for sharing
   531 parameters (as in CASL, for example); just specify something like
   532 ``var x + var y + struct M'' as import;
   533 
   534 * Pure: improved thms_containing: proper indexing of facts instead of
   535 raw theorems; check validity of results wrt. current name space;
   536 include local facts of proof configuration (also covers active
   537 locales), cover fixed variables in index; may use "_" in term
   538 specification; an optional limit for the number of printed facts may
   539 be given (the default is 40);
   540 
   541 * Pure: disallow duplicate fact bindings within new-style theory files
   542 (batch-mode only);
   543 
   544 * Provers: improved induct method: assumptions introduced by case
   545 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   546 the goal statement); "foo" still refers to all facts collectively;
   547 
   548 * Provers: the function blast.overloaded has been removed: all constants
   549 are regarded as potentially overloaded, which improves robustness in exchange
   550 for slight decrease in efficiency;
   551 
   552 * Provers/linorder: New generic prover for transitivity reasoning over
   553 linear orders.  Note: this prover is not efficient!
   554 
   555 * Isar: preview of problems to finish 'show' now produce an error
   556 rather than just a warning (in interactive mode);
   557 
   558 
   559 *** HOL ***
   560 
   561 * arith(_tac)
   562 
   563  - Produces a counter example if it cannot prove a goal.
   564    Note that the counter example may be spurious if the goal is not a formula
   565    of quantifier-free linear arithmetic.
   566    In ProofGeneral the counter example appears in the trace buffer.
   567 
   568  - Knows about div k and mod k where k is a numeral of type nat or int.
   569 
   570  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   571    linear arithmetic fails. This takes account of quantifiers and divisibility.
   572    Presburger arithmetic can also be called explicitly via presburger(_tac).
   573 
   574 * simp's arithmetic capabilities have been enhanced a bit: it now
   575 takes ~= in premises into account (by performing a case split);
   576 
   577 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   578 are distributed over a sum of terms;
   579 
   580 * New tactic "trans_tac" and method "trans" instantiate
   581 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   582 "<=", "<" and "=").
   583 
   584 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   585 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   586 
   587 * 'typedef' command has new option "open" to suppress the set
   588 definition;
   589 
   590 * functions Min and Max on finite sets have been introduced (theory
   591 Finite_Set);
   592 
   593 * attribute [symmetric] now works for relations as well; it turns
   594 (x,y) : R^-1 into (y,x) : R, and vice versa;
   595 
   596 * induct over a !!-quantified statement (say !!x1..xn):
   597   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   598 
   599 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   600 %x. None. Warning: empty_def now refers to the previously hidden definition
   601 of the empty set.
   602 
   603 * Algebra: formalization of classical algebra.  Intended as base for
   604 any algebraic development in Isabelle.  Currently covers group theory
   605 (up to Sylow's theorem) and ring theory (Universal Property of
   606 Univariate Polynomials).  Contributions welcome;
   607 
   608 * GroupTheory: deleted, since its material has been moved to Algebra;
   609 
   610 * Complex: new directory of the complex numbers with numeric constants,
   611 nonstandard complex numbers, and some complex analysis, standard and
   612 nonstandard (Jacques Fleuriot);
   613 
   614 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   615 
   616 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   617 Fleuriot);
   618 
   619 * Real/HahnBanach: updated and adapted to locales;
   620 
   621 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   622 Gray and Kramer);
   623 
   624 * UNITY: added the Meier-Sanders theory of progress sets;
   625 
   626 * MicroJava: bytecode verifier and lightweight bytecode verifier
   627 as abstract algorithms, instantiated to the JVM;
   628 
   629 * Bali: Java source language formalization. Type system, operational
   630 semantics, axiomatic semantics. Supported language features:
   631 classes, interfaces, objects,virtual methods, static methods,
   632 static/instance fields, arrays, access modifiers, definite
   633 assignment, exceptions.
   634 
   635 
   636 *** ZF ***
   637 
   638 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   639 universe, etc.);
   640 
   641 * Main ZF: virtually all theories converted to new-style format;
   642 
   643 
   644 *** ML ***
   645 
   646 * Pure: Tactic.prove provides sane interface for internal proofs;
   647 omits the infamous "standard" operation, so this is more appropriate
   648 than prove_goalw_cterm in many situations (e.g. in simprocs);
   649 
   650 * Pure: improved error reporting of simprocs;
   651 
   652 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   653 up simprocs;
   654 
   655 
   656 *** Document preparation ***
   657 
   658 * uses \par instead of \\ for line breaks in theory text. This may
   659 shift some page breaks in large documents. To get the old behaviour
   660 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   661 
   662 * minimized dependencies of isabelle.sty and isabellesym.sty on
   663 other packages
   664 
   665 * \<euro> now needs package babel/greek instead of marvosym (which
   666 broke \Rightarrow)
   667 
   668 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   669 textcomp package)
   670 
   671 
   672 
   673 New in Isabelle2002 (March 2002)
   674 --------------------------------
   675 
   676 *** Document preparation ***
   677 
   678 * greatly simplified document preparation setup, including more
   679 graceful interpretation of isatool usedir -i/-d/-D options, and more
   680 instructive isatool mkdir; users should basically be able to get
   681 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   682 users may run a separate document processing stage manually like this:
   683 "isatool usedir -D output HOL Test && isatool document Test/output";
   684 
   685 * theory dependency graph may now be incorporated into documents;
   686 isatool usedir -g true will produce session_graph.eps/.pdf for use
   687 with \includegraphics of LaTeX;
   688 
   689 * proper spacing of consecutive markup elements, especially text
   690 blocks after section headings;
   691 
   692 * support bold style (for single symbols only), input syntax is like
   693 this: "\<^bold>\<alpha>" or "\<^bold>A";
   694 
   695 * \<bullet> is now output as bold \cdot by default, which looks much
   696 better in printed text;
   697 
   698 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   699 note that these symbols are currently unavailable in Proof General /
   700 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   701 
   702 * isatool latex no longer depends on changed TEXINPUTS, instead
   703 isatool document copies the Isabelle style files to the target
   704 location;
   705 
   706 
   707 *** Isar ***
   708 
   709 * Pure/Provers: improved proof by cases and induction;
   710   - 'case' command admits impromptu naming of parameters (such as
   711     "case (Suc n)");
   712   - 'induct' method divinates rule instantiation from the inductive
   713     claim; no longer requires excessive ?P bindings for proper
   714     instantiation of cases;
   715   - 'induct' method properly enumerates all possibilities of set/type
   716     rules; as a consequence facts may be also passed through *type*
   717     rules without further ado;
   718   - 'induct' method now derives symbolic cases from the *rulified*
   719     rule (before it used to rulify cases stemming from the internal
   720     atomized version); this means that the context of a non-atomic
   721     statement becomes is included in the hypothesis, avoiding the
   722     slightly cumbersome show "PROP ?case" form;
   723   - 'induct' may now use elim-style induction rules without chaining
   724     facts, using ``missing'' premises from the goal state; this allows
   725     rules stemming from inductive sets to be applied in unstructured
   726     scripts, while still benefitting from proper handling of non-atomic
   727     statements; NB: major inductive premises need to be put first, all
   728     the rest of the goal is passed through the induction;
   729   - 'induct' proper support for mutual induction involving non-atomic
   730     rule statements (uses the new concept of simultaneous goals, see
   731     below);
   732   - append all possible rule selections, but only use the first
   733     success (no backtracking);
   734   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   735   - undeclared rule case names default to numbers 1, 2, 3, ...;
   736   - added 'print_induct_rules' (covered by help item in recent Proof
   737     General versions);
   738   - moved induct/cases attributes to Pure, methods to Provers;
   739   - generic method setup instantiated for FOL and HOL;
   740 
   741 * Pure: support multiple simultaneous goal statements, for example
   742 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   743 meta-level mechanism, this acts as if several individual goals had
   744 been stated separately; in particular common proof methods need to be
   745 repeated in order to cover all claims; note that a single elimination
   746 step is *not* sufficient to establish the two conjunctions, so this
   747 fails:
   748 
   749   assume "A & B" then have A and B ..   (*".." fails*)
   750 
   751 better use "obtain" in situations as above; alternative refer to
   752 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   753 
   754 * Pure: proper integration with ``locales''; unlike the original
   755 version by Florian Kammller, Isar locales package high-level proof
   756 contexts rather than raw logical ones (e.g. we admit to include
   757 attributes everywhere); operations on locales include merge and
   758 rename; support for implicit arguments (``structures''); simultaneous
   759 type-inference over imports and text; see also HOL/ex/Locales.thy for
   760 some examples;
   761 
   762 * Pure: the following commands have been ``localized'', supporting a
   763 target locale specification "(in name)": 'lemma', 'theorem',
   764 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   765 stored both within the locale and at the theory level (exported and
   766 qualified by the locale name);
   767 
   768 * Pure: theory goals may now be specified in ``long'' form, with
   769 ad-hoc contexts consisting of arbitrary locale elements. for example
   770 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   771 definitions may be given, too); the result is a meta-level rule with
   772 the context elements being discharged in the obvious way;
   773 
   774 * Pure: new proof command 'using' allows to augment currently used
   775 facts after a goal statement ('using' is syntactically analogous to
   776 'apply', but acts on the goal's facts only); this allows chained facts
   777 to be separated into parts given before and after a claim, as in
   778 ``from a and b have C using d and e <proof>'';
   779 
   780 * Pure: renamed "antecedent" case to "rule_context";
   781 
   782 * Pure: new 'judgment' command records explicit information about the
   783 object-logic embedding (used by several tools internally); no longer
   784 use hard-wired "Trueprop";
   785 
   786 * Pure: added 'corollary' command;
   787 
   788 * Pure: fixed 'token_translation' command;
   789 
   790 * Pure: removed obsolete 'exported' attribute;
   791 
   792 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   793 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   794 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   795 
   796 * Pure: method 'atomize' presents local goal premises as object-level
   797 statements (atomic meta-level propositions); setup controlled via
   798 rewrite rules declarations of 'atomize' attribute; example
   799 application: 'induct' method with proper rule statements in improper
   800 proof *scripts*;
   801 
   802 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   803 now consider the syntactic context of assumptions, giving a better
   804 chance to get type-inference of the arguments right (this is
   805 especially important for locales);
   806 
   807 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   808 mode;
   809 
   810 * Pure/obtain: the formal conclusion "thesis", being marked as
   811 ``internal'', may no longer be reference directly in the text;
   812 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   813 situations;
   814 
   815 * Pure: generic 'sym' attribute which declares a rule both as pure
   816 'elim?' and for the 'symmetric' operation;
   817 
   818 * Pure: marginal comments ``--'' may now occur just anywhere in the
   819 text; the fixed correlation with particular command syntax has been
   820 discontinued;
   821 
   822 * Pure: new method 'rules' is particularly well-suited for proof
   823 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   824 but often produces more compact proof terms with less detours;
   825 
   826 * Pure/Provers/classical: simplified integration with pure rule
   827 attributes and methods; the classical "intro?/elim?/dest?"
   828 declarations coincide with the pure ones; the "rule" method no longer
   829 includes classically swapped intros; "intro" and "elim" methods no
   830 longer pick rules from the context; also got rid of ML declarations
   831 AddXIs/AddXEs/AddXDs; all of this has some potential for
   832 INCOMPATIBILITY;
   833 
   834 * Provers/classical: attribute 'swapped' produces classical inversions
   835 of introduction rules;
   836 
   837 * Provers/simplifier: 'simplified' attribute may refer to explicit
   838 rules instead of full simplifier context; 'iff' attribute handles
   839 conditional rules;
   840 
   841 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   842 
   843 * HOL: 'recdef' now fails on unfinished automated proofs, use
   844 "(permissive)" option to recover old behavior;
   845 
   846 * HOL: 'inductive' no longer features separate (collective) attributes
   847 for 'intros' (was found too confusing);
   848 
   849 * HOL: properly declared induction rules less_induct and
   850 wf_induct_rule;
   851 
   852 
   853 *** HOL ***
   854 
   855 * HOL: moved over to sane numeral syntax; the new policy is as
   856 follows:
   857 
   858   - 0 and 1 are polymorphic constants, which are defined on any
   859   numeric type (nat, int, real etc.);
   860 
   861   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   862   binary representation internally;
   863 
   864   - type nat has special constructor Suc, and generally prefers Suc 0
   865   over 1::nat and Suc (Suc 0) over 2::nat;
   866 
   867 This change may cause significant problems of INCOMPATIBILITY; here
   868 are some hints on converting existing sources:
   869 
   870   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   871   entities, so expressions involving "-" (unary or binary minus) need
   872   to be spaced properly;
   873 
   874   - existing occurrences of "1" may need to be constraint "1::nat" or
   875   even replaced by Suc 0; similar for old "2";
   876 
   877   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   878 
   879   - remove all special provisions on numerals in proofs;
   880 
   881 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   882 representation (depends on bin_arith_simps in the default context);
   883 
   884 * HOL: symbolic syntax for x^2 (numeral 2);
   885 
   886 * HOL: the class of all HOL types is now called "type" rather than
   887 "term"; INCOMPATIBILITY, need to adapt references to this type class
   888 in axclass/classes, instance/arities, and (usually rare) occurrences
   889 in typings (of consts etc.); internally the class is called
   890 "HOL.type", ML programs should refer to HOLogic.typeS;
   891 
   892 * HOL/record package improvements:
   893   - new derived operations "fields" to build a partial record section,
   894     "extend" to promote a fixed record to a record scheme, and
   895     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   896     declared as simp by default;
   897   - shared operations ("more", "fields", etc.) now need to be always
   898     qualified) --- potential INCOMPATIBILITY;
   899   - removed "make_scheme" operations (use "make" with "extend") --
   900     INCOMPATIBILITY;
   901   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   902   - provides cases/induct rules for use with corresponding Isar
   903     methods (for concrete records, record schemes, concrete more
   904     parts, and schematic more parts -- in that order);
   905   - internal definitions directly based on a light-weight abstract
   906     theory of product types over typedef rather than datatype;
   907 
   908 * HOL: generic code generator for generating executable ML code from
   909 specifications; specific support for HOL constructs such as inductive
   910 datatypes and sets, as well as recursive functions; can be invoked
   911 via 'generate_code' theory section;
   912 
   913 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   914 
   915 * HOL: consolidated and renamed several theories.  In particular:
   916         Ord.thy has been absorbed into HOL.thy
   917         String.thy has been absorbed into List.thy
   918 
   919 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   920 (beware of argument permutation!);
   921 
   922 * HOL: linorder_less_split superseded by linorder_cases;
   923 
   924 * HOL/List: "nodups" renamed to "distinct";
   925 
   926 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   927 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   928   - Ex_def has changed, now need to use some_eq_ex
   929 
   930 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   931 in this (rare) case use:
   932 
   933   delSWrapper "split_all_tac"
   934   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   935 
   936 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   937 MAY FAIL;
   938 
   939 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   940 Isabelle's type classes, ^ on functions and relations has too general
   941 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   942 necessary to attach explicit type constraints;
   943 
   944 * HOL/Relation: the prefix name of the infix "O" has been changed from
   945 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   946 renamed accordingly (eg "compI" -> "rel_compI").
   947 
   948 * HOL: syntax translations now work properly with numerals and records
   949 expressions;
   950 
   951 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   952 of "lam" -- INCOMPATIBILITY;
   953 
   954 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   955 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   956 renamed "Product_Type.unit";
   957 
   958 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   959 
   960 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   961 the "cases" method);
   962 
   963 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   964 Florian Kammller);
   965 
   966 * HOL/IMP: updated and converted to new-style theory format; several
   967 parts turned into readable document, with proper Isar proof texts and
   968 some explanations (by Gerwin Klein);
   969 
   970 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   971 
   972 * HOL-Hyperreal is now a logic image;
   973 
   974 
   975 *** HOLCF ***
   976 
   977 * Isar: consts/constdefs supports mixfix syntax for continuous
   978 operations;
   979 
   980 * Isar: domain package adapted to new-style theory format, e.g. see
   981 HOLCF/ex/Dnat.thy;
   982 
   983 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   984 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   985 lift.induct_tac, always use UU instead of Undef;
   986 
   987 * HOLCF/IMP: updated and converted to new-style theory;
   988 
   989 
   990 *** ZF ***
   991 
   992 * Isar: proper integration of logic-specific tools and packages,
   993 including theory commands '(co)inductive', '(co)datatype',
   994 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   995 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   996 
   997 * theory Main no longer includes AC; for the Axiom of Choice, base
   998 your theory on Main_ZFC;
   999 
  1000 * the integer library now covers quotients and remainders, with many
  1001 laws relating division to addition, multiplication, etc.;
  1002 
  1003 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1004 typeless version of the formalism;
  1005 
  1006 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1007 format;
  1008 
  1009 * ZF/Induct: new directory for examples of inductive definitions,
  1010 including theory Multiset for multiset orderings; converted to
  1011 new-style theory format;
  1012 
  1013 * ZF: many new theorems about lists, ordinals, etc.;
  1014 
  1015 
  1016 *** General ***
  1017 
  1018 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1019 variable proof controls level of detail: 0 = no proofs (only oracle
  1020 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1021 also ref manual for further ML interfaces;
  1022 
  1023 * Pure/axclass: removed obsolete ML interface
  1024 goal_subclass/goal_arity;
  1025 
  1026 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1027 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1028 separate tokens, so expressions involving minus need to be spaced
  1029 properly;
  1030 
  1031 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1032 rather than "infixl" or "infixr";
  1033 
  1034 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1035 sort constraint specifications in type inference; e.g. "x::_::foo"
  1036 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1037 type variable);
  1038 
  1039 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1040 control output of nested => (types); the default behavior is
  1041 "type_brackets";
  1042 
  1043 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1044 tokens into AST constants;
  1045 
  1046 * Pure/syntax: prefer later declarations of translations and print
  1047 translation functions; potential INCOMPATIBILITY: need to reverse
  1048 multiple declarations for same syntax element constant;
  1049 
  1050 * Pure/show_hyps reset by default (in accordance to existing Isar
  1051 practice);
  1052 
  1053 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1054 addSafter;
  1055 
  1056 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1057 as well;
  1058 
  1059 * system: tested support for MacOS X; should be able to get Isabelle +
  1060 Proof General to work in a plain Terminal after installing Poly/ML
  1061 (e.g. from the Isabelle distribution area) and GNU bash alone
  1062 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1063 support requires further installations, e.g. from
  1064 http://fink.sourceforge.net/);
  1065 
  1066 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1067 
  1068 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1069 of 40 MB), cf. ML_OPTIONS;
  1070 
  1071 * system: Proof General keywords specification is now part of the
  1072 Isabelle distribution (see etc/isar-keywords.el);
  1073 
  1074 * system: support for persistent Proof General sessions (refrain from
  1075 outdating all loaded theories on startup); user may create writable
  1076 logic images like this: ``isabelle -q HOL Test'';
  1077 
  1078 * system: smart selection of Isabelle process versus Isabelle
  1079 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1080 run both "isabelle" and "Isabelle" even if file names are badly
  1081 damaged (executable inspects the case of the first letter of its own
  1082 name); added separate "isabelle-process" and "isabelle-interface";
  1083 
  1084 * system: refrain from any attempt at filtering input streams; no
  1085 longer support ``8bit'' encoding of old isabelle font, instead proper
  1086 iso-latin characters may now be used; the related isatools
  1087 "symbolinput" and "nonascii" have disappeared as well;
  1088 
  1089 * system: removed old "xterm" interface (the print modes "xterm" and
  1090 "xterm_color" are still available for direct use in a suitable
  1091 terminal);
  1092 
  1093 
  1094 
  1095 New in Isabelle99-2 (February 2001)
  1096 -----------------------------------
  1097 
  1098 *** Overview of INCOMPATIBILITIES ***
  1099 
  1100 * HOL: please note that theories in the Library and elsewhere often use the
  1101 new-style (Isar) format; to refer to their theorems in an ML script you must
  1102 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1103 
  1104 * HOL: inductive package no longer splits induction rule aggressively,
  1105 but only as far as specified by the introductions given; the old
  1106 format may be recovered via ML function complete_split_rule or attribute
  1107 'split_rule (complete)';
  1108 
  1109 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1110 gfp_Tarski to gfp_unfold;
  1111 
  1112 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1113 
  1114 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1115 relation); infix "^^" has been renamed "``"; infix "``" has been
  1116 renamed "`"; "univalent" has been renamed "single_valued";
  1117 
  1118 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1119 operation;
  1120 
  1121 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1122 
  1123 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1124 
  1125 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1126 consequence, it is no longer monotonic wrt. the local goal context
  1127 (which is now passed through the inductive cases);
  1128 
  1129 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1130 \<gg> to \<ggreater>;
  1131 
  1132 
  1133 *** Document preparation ***
  1134 
  1135 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1136 available: are "it" for near math-mode best-style output, "sl" for
  1137 slanted text style, and "tt" for plain type-writer; if no
  1138 \isabellestyle command is given, output is according to slanted
  1139 type-writer);
  1140 
  1141 * support sub/super scripts (for single symbols only), input syntax is
  1142 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1143 
  1144 * some more standard symbols; see Appendix A of the system manual for
  1145 the complete list of symbols defined in isabellesym.sty;
  1146 
  1147 * improved isabelle style files; more abstract symbol implementation
  1148 (should now use \isamath{...} and \isatext{...} in custom symbol
  1149 definitions);
  1150 
  1151 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1152 state; Note that presentation of goal states does not conform to
  1153 actual human-readable proof documents.  Please do not include goal
  1154 states into document output unless you really know what you are doing!
  1155 
  1156 * proper indentation of antiquoted output with proportional LaTeX
  1157 fonts;
  1158 
  1159 * no_document ML operator temporarily disables LaTeX document
  1160 generation;
  1161 
  1162 * isatool unsymbolize tunes sources for plain ASCII communication;
  1163 
  1164 
  1165 *** Isar ***
  1166 
  1167 * Pure: Isar now suffers initial goal statements to contain unbound
  1168 schematic variables (this does not conform to actual readable proof
  1169 documents, due to unpredictable outcome and non-compositional proof
  1170 checking); users who know what they are doing may use schematic goals
  1171 for Prolog-style synthesis of proven results;
  1172 
  1173 * Pure: assumption method (an implicit finishing) now handles actual
  1174 rules as well;
  1175 
  1176 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1177 initial goal, declare "that" only as Pure intro (only for single
  1178 steps); the "that" rule assumption may now be involved in implicit
  1179 finishing, thus ".." becomes a feasible for trivial obtains;
  1180 
  1181 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1182 instance proofs may be performed by "..";
  1183 
  1184 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1185 statements as well;
  1186 
  1187 * Pure: more robust selection of calculational rules;
  1188 
  1189 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1190 rule (as well as the assumption rule);
  1191 
  1192 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1193 lemmas, using the graph browser tool;
  1194 
  1195 * Pure: predict failure of "show" in interactive mode;
  1196 
  1197 * Pure: 'thms_containing' now takes actual terms as arguments;
  1198 
  1199 * HOL: improved method 'induct' --- now handles non-atomic goals
  1200 (potential INCOMPATIBILITY); tuned error handling;
  1201 
  1202 * HOL: cases and induct rules now provide explicit hints about the
  1203 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1204 any remaining facts are inserted into the goal verbatim;
  1205 
  1206 * HOL: local contexts (aka cases) may now contain term bindings as
  1207 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1208 the result to be shown in each case;
  1209 
  1210 * HOL: added 'recdef_tc' command;
  1211 
  1212 * isatool convert assists in eliminating legacy ML scripts;
  1213 
  1214 
  1215 *** HOL ***
  1216 
  1217 * HOL/Library: a collection of generic theories to be used together
  1218 with main HOL; the theory loader path already includes this directory
  1219 by default; the following existing theories have been moved here:
  1220 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1221 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1222 
  1223 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1224 modelling and verification task performed in Isabelle/HOL +
  1225 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1226 
  1227 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1228 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1229 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1230 'domain', this makes the theory consistent with mathematical
  1231 literature;
  1232 
  1233 * HOL basics: added overloaded operations "inverse" and "divide"
  1234 (infix "/"), syntax for generic "abs" operation, generic summation
  1235 operator \<Sum>;
  1236 
  1237 * HOL/typedef: simplified package, provide more useful rules (see also
  1238 HOL/subset.thy);
  1239 
  1240 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1241 now expressed as a proper nested rule (old-style tactic scripts may
  1242 require atomize_strip_tac to cope with non-atomic premises);
  1243 
  1244 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1245 to "split_conv" (old name still available for compatibility);
  1246 
  1247 * HOL: improved concrete syntax for strings (e.g. allows translation
  1248 rules with string literals);
  1249 
  1250 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1251  and Fleuriot's mechanization of analysis, including the transcendental
  1252  functions for the reals;
  1253 
  1254 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1255 
  1256 
  1257 *** CTT ***
  1258 
  1259 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1260 "lam" is displayed as TWO lambda-symbols
  1261 
  1262 * CTT: theory Main now available, containing everything (that is, Bool
  1263 and Arith);
  1264 
  1265 
  1266 *** General ***
  1267 
  1268 * Pure: the Simplifier has been implemented properly as a derived rule
  1269 outside of the actual kernel (at last!); the overall performance
  1270 penalty in practical applications is about 50%, while reliability of
  1271 the Isabelle inference kernel has been greatly improved;
  1272 
  1273 * print modes "brackets" and "no_brackets" control output of nested =>
  1274 (types) and ==> (props); the default behaviour is "brackets";
  1275 
  1276 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1277 as assumptions as well;
  1278 
  1279 * system: support Poly/ML 4.0;
  1280 
  1281 * system: isatool install handles KDE version 1 or 2;
  1282 
  1283 
  1284 
  1285 New in Isabelle99-1 (October 2000)
  1286 ----------------------------------
  1287 
  1288 *** Overview of INCOMPATIBILITIES ***
  1289 
  1290 * HOL: simplification of natural numbers is much changed; to partly
  1291 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1292 issue the following ML commands:
  1293 
  1294   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1295   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1296 
  1297 * HOL: simplification no longer dives into case-expressions; this is
  1298 controlled by "t.weak_case_cong" for each datatype t;
  1299 
  1300 * HOL: nat_less_induct renamed to less_induct;
  1301 
  1302 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1303 fixsome to patch .thy and .ML sources automatically;
  1304 
  1305   select_equality  -> some_equality
  1306   select_eq_Ex     -> some_eq_ex
  1307   selectI2EX       -> someI2_ex
  1308   selectI2         -> someI2
  1309   selectI          -> someI
  1310   select1_equality -> some1_equality
  1311   Eps_sym_eq       -> some_sym_eq_trivial
  1312   Eps_eq           -> some_eq_trivial
  1313 
  1314 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1315 
  1316 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1317 instead);
  1318 
  1319 * HOL: the recursion equations generated by 'recdef' are now called
  1320 f.simps instead of f.rules;
  1321 
  1322 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1323 
  1324 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1325 sometimes be needed;
  1326 
  1327 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1328 
  1329 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1330 
  1331 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1332 product is now "<*>" instead of "Times"; the lexicographic product is
  1333 now "<*lex*>" instead of "**";
  1334 
  1335 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1336 of main HOL, but was unused); better use HOL's datatype package;
  1337 
  1338 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1339 the old syntax may be recovered as follows:
  1340 
  1341   syntax (symbols)
  1342     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1343       (infixl "\\<oplus>" 100)
  1344 
  1345 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1346 
  1347 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1348 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1349 internally;
  1350 
  1351 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1352 changed from A/r to A//r;
  1353 
  1354 * ZF: new treatment of arithmetic (nat & int) may break some old
  1355 proofs;
  1356 
  1357 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1358 rulify -> rule_format, elimify -> elim_format, ...);
  1359 
  1360 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1361 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1362 should have to change intro!! to intro? only); replaced "delrule" by
  1363 "rule del";
  1364 
  1365 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1366 
  1367 * Provers: strengthened force_tac by using new first_best_tac;
  1368 
  1369 * LaTeX document preparation: several changes of isabelle.sty (see
  1370 lib/texinputs);
  1371 
  1372 
  1373 *** Document preparation ***
  1374 
  1375 * formal comments (text blocks etc.) in new-style theories may now
  1376 contain antiquotations of thm/prop/term/typ/text to be presented
  1377 according to latex print mode; concrete syntax is like this:
  1378 @{term[show_types] "f(x) = a + x"};
  1379 
  1380 * isatool mkdir provides easy setup of Isabelle session directories,
  1381 including proper document sources;
  1382 
  1383 * generated LaTeX sources are now deleted after successful run
  1384 (isatool document -c); may retain a copy somewhere else via -D option
  1385 of isatool usedir;
  1386 
  1387 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1388 style files, achieving self-contained LaTeX sources and simplifying
  1389 LaTeX debugging;
  1390 
  1391 * old-style theories now produce (crude) LaTeX output as well;
  1392 
  1393 * browser info session directories are now self-contained (may be put
  1394 on WWW server seperately); improved graphs of nested sessions; removed
  1395 graph for 'all sessions';
  1396 
  1397 * several improvements in isabelle style files; \isabellestyle{it}
  1398 produces fake math mode output; \isamarkupheader is now \section by
  1399 default; see lib/texinputs/isabelle.sty etc.;
  1400 
  1401 
  1402 *** Isar ***
  1403 
  1404 * Isar/Pure: local results and corresponding term bindings are now
  1405 subject to Hindley-Milner polymorphism (similar to ML); this
  1406 accommodates incremental type-inference very nicely;
  1407 
  1408 * Isar/Pure: new derived language element 'obtain' supports
  1409 generalized existence reasoning;
  1410 
  1411 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1412 support accumulation of results, without applying any rules yet;
  1413 useful to collect intermediate results without explicit name
  1414 references, and for use with transitivity rules with more than 2
  1415 premises;
  1416 
  1417 * Isar/Pure: scalable support for case-analysis type proofs: new
  1418 'case' language element refers to local contexts symbolically, as
  1419 produced by certain proof methods; internally, case names are attached
  1420 to theorems as "tags";
  1421 
  1422 * Isar/Pure: theory command 'hide' removes declarations from
  1423 class/type/const name spaces;
  1424 
  1425 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1426 indicate potential overloading;
  1427 
  1428 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1429 
  1430 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1431 "{a,b,c}" instead of {a,b,c};
  1432 
  1433 * Isar/Pure now provides its own version of intro/elim/dest
  1434 attributes; useful for building new logics, but beware of confusion
  1435 with the version in Provers/classical;
  1436 
  1437 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1438 case name 'antecedent';
  1439 
  1440 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1441 to the current context is now done automatically);
  1442 
  1443 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1444 for definining proof methods in ML;
  1445 
  1446 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1447 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1448 most cases, one should have to change intro!! to intro? only);
  1449 replaced "delrule" by "rule del";
  1450 
  1451 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1452 'symmetric' attribute (the latter supercedes [RS sym]);
  1453 
  1454 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1455 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1456 well (including splits);
  1457 
  1458 * Isar/Provers: Simplifier and Classical methods now support all kind
  1459 of modifiers used in the past, including 'cong', 'iff', etc.
  1460 
  1461 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1462 of Simplifier and Classical reasoner);
  1463 
  1464 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1465 now support named cases; major packages (inductive, datatype, primrec,
  1466 recdef) support case names and properly name parameters;
  1467 
  1468 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1469 monotonicity conditions are extracted to be proven at end of
  1470 calculations;
  1471 
  1472 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1473 method anyway;
  1474 
  1475 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1476 split_if split_if_asm; datatype package provides theorems foo.splits =
  1477 foo.split foo.split_asm for each datatype;
  1478 
  1479 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1480 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1481 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1482 use "(cases (simplified))" method in proper proof texts);
  1483 
  1484 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1485 
  1486 * Isar: names of theorems etc. may be natural numbers as well;
  1487 
  1488 * Isar: 'pr' command: optional arguments for goals_limit and
  1489 ProofContext.prems_limit; no longer prints theory contexts, but only
  1490 proof states;
  1491 
  1492 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1493 additional print modes to be specified; e.g. "pr(latex)" will print
  1494 proof state according to the Isabelle LaTeX style;
  1495 
  1496 * Isar: improved support for emulating tactic scripts, including proof
  1497 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1498 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1499 (for HOL datatypes);
  1500 
  1501 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1502 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1503 'proof method scripts' have to be in depth-first order;
  1504 
  1505 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1506 
  1507 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1508 should instead use individual commands for printing items
  1509 (print_commands, print_methods etc.);
  1510 
  1511 * Isar: added 'nothing' --- the empty list of theorems;
  1512 
  1513 
  1514 *** HOL ***
  1515 
  1516 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1517 corresponding virtual machine and a specification of its bytecode
  1518 verifier and a lightweight bytecode verifier, including proofs of
  1519 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1520 Cornelia Pusch (see also the homepage of project Bali at
  1521 http://isabelle.in.tum.de/Bali/);
  1522 
  1523 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1524 Clemens Ballarin;
  1525 
  1526 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1527 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1528 Rasmussen;
  1529 
  1530 * HOL/Lattice: fundamental concepts of lattice theory and order
  1531 structures, including duals, properties of bounds versus algebraic
  1532 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1533 Theorem for complete lattices etc.; may also serve as a demonstration
  1534 for abstract algebraic reasoning using axiomatic type classes, and
  1535 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1536 
  1537 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1538 von Oheimb;
  1539 
  1540 * HOL/IMPP: extension of IMP with local variables and mutually
  1541 recursive procedures, by David von Oheimb;
  1542 
  1543 * HOL/Lambda: converted into new-style theory and document;
  1544 
  1545 * HOL/ex/Multiquote: example of multiple nested quotations and
  1546 anti-quotations -- basically a generalized version of de-Bruijn
  1547 representation; very useful in avoiding lifting of operations;
  1548 
  1549 * HOL/record: added general record equality rule to simpset; fixed
  1550 select-update simplification procedure to handle extended records as
  1551 well; admit "r" as field name;
  1552 
  1553 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1554 other numeric types and also as the identity of groups, rings, etc.;
  1555 
  1556 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1557 Types nat and int belong to this axclass;
  1558 
  1559 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1560    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1561    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1562   two terms #m*u and #n*u are replaced by #(m+n)*u
  1563     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1564   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1565     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1566 
  1567 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1568 powerful prover for predicate logic but knows nothing of clasets; see
  1569 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1570 
  1571 * HOL: new version of "case_tac" subsumes both boolean case split and
  1572 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1573 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1574 
  1575 * HOL: simplification no longer dives into case-expressions: only the
  1576 selector expression is simplified, but not the remaining arms; to
  1577 enable full simplification of case-expressions for datatype t, you may
  1578 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1579 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1580 
  1581 * HOL/recdef: the recursion equations generated by 'recdef' for
  1582 function 'f' are now called f.simps instead of f.rules; if all
  1583 termination conditions are proved automatically, these simplification
  1584 rules are added to the simpset, as in primrec; rules may be named
  1585 individually as well, resulting in a separate list of theorems for
  1586 each equation;
  1587 
  1588 * HOL/While is a new theory that provides a while-combinator. It
  1589 permits the definition of tail-recursive functions without the
  1590 provision of a termination measure. The latter is necessary once the
  1591 invariant proof rule for while is applied.
  1592 
  1593 * HOL: new (overloaded) notation for the set of elements below/above
  1594 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1595 
  1596 * HOL: theorems impI, allI, ballI bound as "strip";
  1597 
  1598 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1599 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1600 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1601 
  1602 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1603 
  1604 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1605 main HOL, but was unused);
  1606 
  1607 * HOL: fewer consts declared as global (e.g. have to refer to
  1608 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1609 
  1610 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1611 in case of overlap with user translations (e.g. judgements over
  1612 tuples); (note that the underlying logical represenation is still
  1613 bogus);
  1614 
  1615 
  1616 *** ZF ***
  1617 
  1618 * ZF: simplification automatically cancels common terms in arithmetic
  1619 expressions over nat and int;
  1620 
  1621 * ZF: new treatment of nat to minimize type-checking: all operators
  1622 coerce their operands to a natural number using the function natify,
  1623 making the algebraic laws unconditional;
  1624 
  1625 * ZF: as above, for int: operators coerce their operands to an integer
  1626 using the function intify;
  1627 
  1628 * ZF: the integer library now contains many of the usual laws for the
  1629 orderings, including $<=, and monotonicity laws for $+ and $*;
  1630 
  1631 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1632 simplification;
  1633 
  1634 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1635 to the simplifier and classical reasoner simultaneously;
  1636 
  1637 
  1638 *** General ***
  1639 
  1640 * Provers: blast_tac now handles actual object-logic rules as
  1641 assumptions; note that auto_tac uses blast_tac internally as well;
  1642 
  1643 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1644 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1645 
  1646 * Provers: delrules now handles destruct rules as well (no longer need
  1647 explicit make_elim);
  1648 
  1649 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1650   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1651 use instead the strong form,
  1652   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1653 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1654 from destruct-rules;
  1655 
  1656 * Provers: Simplifier.easy_setup provides a fast path to basic
  1657 Simplifier setup for new object-logics;
  1658 
  1659 * Pure: AST translation rules no longer require constant head on LHS;
  1660 
  1661 * Pure: improved name spaces: ambiguous output is qualified; support
  1662 for hiding of names;
  1663 
  1664 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1665 XSYMBOL_HOME; no longer need to do manual configuration in most
  1666 situations;
  1667 
  1668 * system: compression of ML heaps images may now be controlled via -c
  1669 option of isabelle and isatool usedir (currently only observed by
  1670 Poly/ML);
  1671 
  1672 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1673 useful for remote X11);
  1674 
  1675 * system: provide TAGS file for Isabelle sources;
  1676 
  1677 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1678 order;
  1679 
  1680 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1681 timing flag supersedes proof_timing and Toplevel.trace;
  1682 
  1683 * ML: new combinators |>> and |>>> for incremental transformations
  1684 with secondary results (e.g. certain theory extensions):
  1685 
  1686 * ML: PureThy.add_defs gets additional argument to indicate potential
  1687 overloading (usually false);
  1688 
  1689 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1690 results;
  1691 
  1692 
  1693 
  1694 New in Isabelle99 (October 1999)
  1695 --------------------------------
  1696 
  1697 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1698 
  1699 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1700 are no longer simplified.  (This allows the simplifier to unfold recursive
  1701 functional programs.)  To restore the old behaviour, declare
  1702 
  1703     Delcongs [if_weak_cong];
  1704 
  1705 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1706 complement;
  1707 
  1708 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1709 
  1710 * HOL/datatype: mutual_induct_tac no longer exists --
  1711   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1712 
  1713 * HOL/typedef: fixed type inference for representing set; type
  1714 arguments now have to occur explicitly on the rhs as type constraints;
  1715 
  1716 * ZF: The con_defs part of an inductive definition may no longer refer
  1717 to constants declared in the same theory;
  1718 
  1719 * HOL, ZF: the function mk_cases, generated by the inductive
  1720 definition package, has lost an argument.  To simplify its result, it
  1721 uses the default simpset instead of a supplied list of theorems.
  1722 
  1723 * HOL/List: the constructors of type list are now Nil and Cons;
  1724 
  1725 * Simplifier: the type of the infix ML functions
  1726         setSSolver addSSolver setSolver addSolver
  1727 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1728 for packaging solvers. A solver is created via
  1729         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1730 where the string argument is only a comment.
  1731 
  1732 
  1733 *** Proof tools ***
  1734 
  1735 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1736 decision procedure for linear arithmetic. Currently it is used for
  1737 types `nat', `int', and `real' in HOL (see below); it can, should and
  1738 will be instantiated for other types and logics as well.
  1739 
  1740 * The simplifier now accepts rewrite rules with flexible heads, eg
  1741      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1742   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1743   matching.
  1744 
  1745 
  1746 *** General ***
  1747 
  1748 * New Isabelle/Isar subsystem provides an alternative to traditional
  1749 tactical theorem proving; together with the ProofGeneral/isar user
  1750 interface it offers an interactive environment for developing human
  1751 readable proof documents (Isar == Intelligible semi-automated
  1752 reasoning); for further information see isatool doc isar-ref,
  1753 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1754 
  1755 * improved and simplified presentation of theories: better HTML markup
  1756 (including colors), graph views in several sizes; isatool usedir now
  1757 provides a proper interface for user theories (via -P option); actual
  1758 document preparation based on (PDF)LaTeX is available as well (for
  1759 new-style theories only); see isatool doc system for more information;
  1760 
  1761 * native support for Proof General, both for classic Isabelle and
  1762 Isabelle/Isar;
  1763 
  1764 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1765 using the graph browser tool;
  1766 
  1767 * Isabelle manuals now also available as PDF;
  1768 
  1769 * theory loader rewritten from scratch (may not be fully
  1770 bug-compatible); old loadpath variable has been replaced by show_path,
  1771 add_path, del_path, reset_path functions; new operations such as
  1772 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1773 isatool doc ref);
  1774 
  1775 * improved isatool install: option -k creates KDE application icon,
  1776 option -p DIR installs standalone binaries;
  1777 
  1778 * added ML_PLATFORM setting (useful for cross-platform installations);
  1779 more robust handling of platform specific ML images for SML/NJ;
  1780 
  1781 * the settings environment is now statically scoped, i.e. it is never
  1782 created again in sub-processes invoked from isabelle, isatool, or
  1783 Isabelle;
  1784 
  1785 * path element specification '~~' refers to '$ISABELLE_HOME';
  1786 
  1787 * in locales, the "assumes" and "defines" parts may be omitted if
  1788 empty;
  1789 
  1790 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1791 long arrows);
  1792 
  1793 * new print_mode "HTML";
  1794 
  1795 * new flag show_tags controls display of tags of theorems (which are
  1796 basically just comments that may be attached by some tools);
  1797 
  1798 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1799 mode and goal output format:
  1800 
  1801 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1802 244c244
  1803 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1804 ---
  1805 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1806 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1807 181c181
  1808 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1809 ---
  1810 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1811 
  1812 * function bind_thms stores lists of theorems (cf. bind_thm);
  1813 
  1814 * new shorthand tactics ftac, eatac, datac, fatac;
  1815 
  1816 * qed (and friends) now accept "" as result name; in that case the
  1817 theorem is not stored, but proper checks and presentation of the
  1818 result still apply;
  1819 
  1820 * theorem database now also indexes constants "Trueprop", "all",
  1821 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1822 
  1823 
  1824 *** HOL ***
  1825 
  1826 ** HOL arithmetic **
  1827 
  1828 * There are now decision procedures for linear arithmetic over nat and
  1829 int:
  1830 
  1831 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1832 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1833 are treated as atomic; subformulae not involving type `nat' or `int'
  1834 are ignored; quantified subformulae are ignored unless they are
  1835 positive universal or negative existential. The tactic has to be
  1836 invoked by hand and can be a little bit slow. In particular, the
  1837 running time is exponential in the number of occurrences of `min' and
  1838 `max', and `-' on `nat'.
  1839 
  1840 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1841 (negated) (in)equalities among the premises and the conclusion into
  1842 account (i.e. no compound formulae) and does not know about `min' and
  1843 `max', and `-' on `nat'. It is fast and is used automatically by the
  1844 simplifier.
  1845 
  1846 NB: At the moment, these decision procedures do not cope with mixed
  1847 nat/int formulae where the two parts interact, such as `m < n ==>
  1848 int(m) < int(n)'.
  1849 
  1850 * HOL/Numeral provides a generic theory of numerals (encoded
  1851 efficiently as bit strings); setup for types nat/int/real is in place;
  1852 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1853 int, existing theories and proof scripts may require a few additional
  1854 type constraints;
  1855 
  1856 * integer division and remainder can now be performed on constant
  1857 arguments;
  1858 
  1859 * many properties of integer multiplication, division and remainder
  1860 are now available;
  1861 
  1862 * An interface to the Stanford Validity Checker (SVC) is available through the
  1863 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1864 are proved automatically.  SVC must be installed separately, and its results
  1865 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1866 invocation of the underlying oracle).  For SVC see
  1867   http://verify.stanford.edu/SVC
  1868 
  1869 * IsaMakefile: the HOL-Real target now builds an actual image;
  1870 
  1871 
  1872 ** HOL misc **
  1873 
  1874 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1875 (in Isabelle/Isar) -- by Gertrud Bauer;
  1876 
  1877 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1878 analysis for assembly languages with subtypes;
  1879 
  1880 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1881 -- avoids syntactic ambiguities and treats state, transition, and
  1882 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1883 changed syntax and (many) tactics;
  1884 
  1885 * HOL/inductive: Now also handles more general introduction rules such
  1886   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1887   theorems are now maintained within the theory (maintained via the
  1888   "mono" attribute);
  1889 
  1890 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1891   (using function types) such as
  1892 
  1893   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1894 
  1895 * HOL/record: record_simproc (part of the default simpset) takes care
  1896 of selectors applied to updated records; record_split_tac is no longer
  1897 part of the default claset; update_defs may now be removed from the
  1898 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1899 
  1900   claset_ref () := claset() addSWrapper record_split_wrapper;
  1901   Delsimprocs [record_simproc]
  1902 
  1903 * HOL/typedef: fixed type inference for representing set; type
  1904 arguments now have to occur explicitly on the rhs as type constraints;
  1905 
  1906 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1907 names rather than an ML expression;
  1908 
  1909 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1910 supplied later.  Program schemes can be defined, such as
  1911     "While B C s = (if B s then While B C (C s) else s)"
  1912 where the well-founded relation can be chosen after B and C have been given.
  1913 
  1914 * HOL/List: the constructors of type list are now Nil and Cons;
  1915 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1916 course, ML tools referring to List.list.op # etc. have to be adapted;
  1917 
  1918 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1919 disabled by default; run isabelle with option -m HOL to get back to
  1920 the original Gordon/HOL-style output;
  1921 
  1922 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1923 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1924 
  1925 * HOL basic syntax simplified (more orthogonal): all variants of
  1926 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1927 Eps operator is provided as well: "SOME x. P[x]";
  1928 
  1929 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1930 
  1931 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1932 thus available for user theories;
  1933 
  1934 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1935 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1936 time;
  1937 
  1938 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1939 several times and then mp;
  1940 
  1941 
  1942 *** LK ***
  1943 
  1944 * the notation <<...>> is now available as a notation for sequences of
  1945 formulas;
  1946 
  1947 * the simplifier is now installed
  1948 
  1949 * the axiom system has been generalized (thanks to Soren Heilmann)
  1950 
  1951 * the classical reasoner now has a default rule database
  1952 
  1953 
  1954 *** ZF ***
  1955 
  1956 * new primrec section allows primitive recursive functions to be given
  1957 directly (as in HOL) over datatypes and the natural numbers;
  1958 
  1959 * new tactics induct_tac and exhaust_tac for induction (or case
  1960 analysis) over datatypes and the natural numbers;
  1961 
  1962 * the datatype declaration of type T now defines the recursor T_rec;
  1963 
  1964 * simplification automatically does freeness reasoning for datatype
  1965 constructors;
  1966 
  1967 * automatic type-inference, with AddTCs command to insert new
  1968 type-checking rules;
  1969 
  1970 * datatype introduction rules are now added as Safe Introduction rules
  1971 to the claset;
  1972 
  1973 * the syntax "if P then x else y" is now available in addition to
  1974 if(P,x,y);
  1975 
  1976 
  1977 *** Internal programming interfaces ***
  1978 
  1979 * tuned simplifier trace output; new flag debug_simp;
  1980 
  1981 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1982 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1983 
  1984 * AxClass.axclass_tac lost the theory argument;
  1985 
  1986 * tuned current_goals_markers semantics: begin / end goal avoids
  1987 printing empty lines;
  1988 
  1989 * removed prs and prs_fn hook, which was broken because it did not
  1990 include \n in its semantics, forcing writeln to add one
  1991 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1992 string -> unit if you really want to output text without newline;
  1993 
  1994 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1995 plain output, interface builders may have to enable 'isabelle_font'
  1996 mode to get Isabelle font glyphs as before;
  1997 
  1998 * refined token_translation interface; INCOMPATIBILITY: output length
  1999 now of type real instead of int;
  2000 
  2001 * theory loader actions may be traced via new ThyInfo.add_hook
  2002 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2003 your own database of information attached to *whole* theories -- as
  2004 opposed to intra-theory data slots offered via TheoryDataFun;
  2005 
  2006 * proper handling of dangling sort hypotheses (at last!);
  2007 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2008 extra sort hypotheses that can be witnessed from the type signature;
  2009 the force_strip_shyps flag is gone, any remaining shyps are simply
  2010 left in the theorem (with a warning issued by strip_shyps_warning);
  2011 
  2012 
  2013 
  2014 New in Isabelle98-1 (October 1998)
  2015 ----------------------------------
  2016 
  2017 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2018 
  2019 * several changes of automated proof tools;
  2020 
  2021 * HOL: major changes to the inductive and datatype packages, including
  2022 some minor incompatibilities of theory syntax;
  2023 
  2024 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2025 called `inj_on';
  2026 
  2027 * HOL: removed duplicate thms in Arith:
  2028   less_imp_add_less  should be replaced by  trans_less_add1
  2029   le_imp_add_le      should be replaced by  trans_le_add1
  2030 
  2031 * HOL: unary minus is now overloaded (new type constraints may be
  2032 required);
  2033 
  2034 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2035 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2036 now taken as an integer constant.
  2037 
  2038 * Pure: ML function 'theory_of' renamed to 'theory';
  2039 
  2040 
  2041 *** Proof tools ***
  2042 
  2043 * Simplifier:
  2044   1. Asm_full_simp_tac is now more aggressive.
  2045      1. It will sometimes reorient premises if that increases their power to
  2046         simplify.
  2047      2. It does no longer proceed strictly from left to right but may also
  2048         rotate premises to achieve further simplification.
  2049      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2050      old Asm_full_simp_tac in that it does not rotate premises.
  2051   2. The simplifier now knows a little bit about nat-arithmetic.
  2052 
  2053 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2054 allows for selected deletion of wrappers, by introduction of names for
  2055 wrapper functionals.  This implies that addbefore, addSbefore,
  2056 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2057 and that adding two tactics with the same name overwrites the first
  2058 one (emitting a warning).
  2059   type wrapper = (int -> tactic) -> (int -> tactic)
  2060   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2061   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2062   delWrapper, delSWrapper: claset *  string            -> claset
  2063   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2064 
  2065 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2066 semantics; addbefore now affects only the unsafe part of step_tac
  2067 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2068 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2069 by Force_tac;
  2070 
  2071 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2072 compWrapper; added safe wrapper (and access functions for it);
  2073 
  2074 * HOL/split_all_tac is now much faster and fails if there is nothing
  2075 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2076 and the names of the automatically generated variables have changed.
  2077 split_all_tac has moved within claset() from unsafe wrappers to safe
  2078 wrappers, which means that !!-bound variables are split much more
  2079 aggressively, and safe_tac and clarify_tac now split such variables.
  2080 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2081 Note: the same holds for record_split_tac, which does the job of
  2082 split_all_tac for record fields.
  2083 
  2084 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2085 permanently to the default simpset using Addsplits just like
  2086 Addsimps. They can be removed via Delsplits just like
  2087 Delsimps. Lower-case versions are also available.
  2088 
  2089 * HOL/Simplifier: The rule split_if is now part of the default
  2090 simpset. This means that the simplifier will eliminate all occurrences
  2091 of if-then-else in the conclusion of a goal. To prevent this, you can
  2092 either remove split_if completely from the default simpset by
  2093 `Delsplits [split_if]' or remove it in a specific call of the
  2094 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2095 other case splitting rules to/from the default simpset: every datatype
  2096 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2097 t is the name of the datatype).
  2098 
  2099 * Classical reasoner / Simplifier combination: new force_tac (and
  2100 derivatives Force_tac, force) combines rewriting and classical
  2101 reasoning (and whatever other tools) similarly to auto_tac, but is
  2102 aimed to solve the given subgoal completely.
  2103 
  2104 
  2105 *** General ***
  2106 
  2107 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2108 and `goalw': the theory is no longer needed as an explicit argument -
  2109 the current theory context is used; assumptions are no longer returned
  2110 at the ML-level unless one of them starts with ==> or !!; it is
  2111 recommended to convert to these new commands using isatool fixgoal
  2112 (backup your sources first!);
  2113 
  2114 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2115 the current theory context, and 'theory' to lookup stored theories;
  2116 
  2117 * new theory section 'locale' for declaring constants, assumptions and
  2118 definitions that have local scope;
  2119 
  2120 * new theory section 'nonterminals' for purely syntactic types;
  2121 
  2122 * new theory section 'setup' for generic ML setup functions
  2123 (e.g. package initialization);
  2124 
  2125 * the distribution now includes Isabelle icons: see
  2126 lib/logo/isabelle-{small,tiny}.xpm;
  2127 
  2128 * isatool install - install binaries with absolute references to
  2129 ISABELLE_HOME/bin;
  2130 
  2131 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2132 
  2133 * print mode 'emacs' reserved for Isamode;
  2134 
  2135 * support multiple print (ast) translations per constant name;
  2136 
  2137 * theorems involving oracles are now printed with a suffixed [!];
  2138 
  2139 
  2140 *** HOL ***
  2141 
  2142 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2143 
  2144 * HOL/inductive package reorganized and improved: now supports mutual
  2145 definitions such as
  2146 
  2147   inductive EVEN ODD
  2148     intrs
  2149       null "0 : EVEN"
  2150       oddI "n : EVEN ==> Suc n : ODD"
  2151       evenI "n : ODD ==> Suc n : EVEN"
  2152 
  2153 new theorem list "elims" contains an elimination rule for each of the
  2154 recursive sets; inductive definitions now handle disjunctive premises
  2155 correctly (also ZF);
  2156 
  2157 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2158 "mutual_induct" no longer exists - the induction rule is always
  2159 contained in "induct";
  2160 
  2161 
  2162 * HOL/datatype package re-implemented and greatly improved: now
  2163 supports mutually recursive datatypes such as
  2164 
  2165   datatype
  2166     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2167             | SUM ('a aexp) ('a aexp)
  2168             | DIFF ('a aexp) ('a aexp)
  2169             | NUM 'a
  2170   and
  2171     'a bexp = LESS ('a aexp) ('a aexp)
  2172             | AND ('a bexp) ('a bexp)
  2173             | OR ('a bexp) ('a bexp)
  2174 
  2175 as well as indirectly recursive datatypes such as
  2176 
  2177   datatype
  2178     ('a, 'b) term = Var 'a
  2179                   | App 'b ((('a, 'b) term) list)
  2180 
  2181 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2182 induction on mutually / indirectly recursive datatypes.
  2183 
  2184 Primrec equations are now stored in theory and can be accessed via
  2185 <function_name>.simps.
  2186 
  2187 INCOMPATIBILITIES:
  2188 
  2189   - Theories using datatypes must now have theory Datatype as an
  2190     ancestor.
  2191   - The specific <typename>.induct_tac no longer exists - use the
  2192     generic induct_tac instead.
  2193   - natE has been renamed to nat.exhaust - use exhaust_tac
  2194     instead of res_inst_tac ... natE. Note that the variable
  2195     names in nat.exhaust differ from the names in natE, this
  2196     may cause some "fragile" proofs to fail.
  2197   - The theorems split_<typename>_case and split_<typename>_case_asm
  2198     have been renamed to <typename>.split and <typename>.split_asm.
  2199   - Since default sorts of type variables are now handled correctly,
  2200     some datatype definitions may have to be annotated with explicit
  2201     sort constraints.
  2202   - Primrec definitions no longer require function name and type
  2203     of recursive argument.
  2204 
  2205 Consider using isatool fixdatatype to adapt your theories and proof
  2206 scripts to the new package (backup your sources first!).
  2207 
  2208 
  2209 * HOL/record package: considerably improved implementation; now
  2210 includes concrete syntax for record types, terms, updates; theorems
  2211 for surjective pairing and splitting !!-bound record variables; proof
  2212 support is as follows:
  2213 
  2214   1) standard conversions (selectors or updates applied to record
  2215 constructor terms) are part of the standard simpset;
  2216 
  2217   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2218 made part of standard simpset and claset via addIffs;
  2219 
  2220   3) a tactic for record field splitting (record_split_tac) is part of
  2221 the standard claset (addSWrapper);
  2222 
  2223 To get a better idea about these rules you may retrieve them via
  2224 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2225 the name of your record type.
  2226 
  2227 The split tactic 3) conceptually simplifies by the following rule:
  2228 
  2229   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2230 
  2231 Thus any record variable that is bound by meta-all will automatically
  2232 blow up into some record constructor term, consequently the
  2233 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2234 solve record problems automatically.
  2235 
  2236 
  2237 * reorganized the main HOL image: HOL/Integ and String loaded by
  2238 default; theory Main includes everything;
  2239 
  2240 * automatic simplification of integer sums and comparisons, using cancellation;
  2241 
  2242 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2243 
  2244 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2245 
  2246 * many new identities for unions, intersections, set difference, etc.;
  2247 
  2248 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2249 called split_if, split_split, split_sum_case and split_nat_case (to go
  2250 with add/delsplits);
  2251 
  2252 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2253 (?x::unit) = (); this is made part of the default simpset, which COULD
  2254 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2255 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2256 unit_abs_eta_conv is added in order to counter the effect of
  2257 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2258 %u.f();
  2259 
  2260 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2261 makes more sense);
  2262 
  2263 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2264   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2265   disjointness reasoning but breaking a few old proofs.
  2266 
  2267 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2268 to 'converse' from 'inverse' (for compatibility with ZF and some
  2269 literature);
  2270 
  2271 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2272 the well-founded relation;
  2273 
  2274 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2275     Compl A.  The "Compl" syntax remains available as input syntax for this
  2276     release ONLY.
  2277 
  2278 * HOL/Update: new theory of function updates:
  2279     f(a:=b) == %x. if x=a then b else f x
  2280 may also be iterated as in f(a:=b,c:=d,...);
  2281 
  2282 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2283 
  2284 * HOL/List:
  2285   - new function list_update written xs[i:=v] that updates the i-th
  2286     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2287   - new function `upt' written [i..j(] which generates the list
  2288     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2289     bound write [i..j], which is a shorthand for [i..j+1(].
  2290   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2291 
  2292 * HOL/Arith:
  2293   - removed 'pred' (predecessor) function;
  2294   - generalized some theorems about n-1;
  2295   - many new laws about "div" and "mod";
  2296   - new laws about greatest common divisors (see theory ex/Primes);
  2297 
  2298 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2299 instead of "inverse";
  2300 
  2301 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2302   of the multiset ordering;
  2303 
  2304 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2305   (not included by default);
  2306 
  2307 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2308 
  2309 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2310   programs, i.e. different program variables may have different types.
  2311 
  2312 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2313   [previously, this check worked only if the rewrite rule was unconditional]
  2314   Now rew can involve either definitions or equalities (either == or =).
  2315 
  2316 
  2317 *** ZF ***
  2318 
  2319 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2320   only the theorems proved on ZF.ML;
  2321 
  2322 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2323   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2324   disjointness reasoning but breaking a few old proofs.
  2325 
  2326 * ZF/Update: new theory of function updates
  2327     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2328   may also be iterated as in f(a:=b,c:=d,...);
  2329 
  2330 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2331 
  2332 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2333   [previously, this check worked only if the rewrite rule was unconditional]
  2334   Now rew can involve either definitions or equalities (either == or =).
  2335 
  2336 * case_tac provided for compatibility with HOL
  2337     (like the old excluded_middle_tac, but with subgoals swapped)
  2338 
  2339 
  2340 *** Internal programming interfaces ***
  2341 
  2342 * Pure: several new basic modules made available for general use, see
  2343 also src/Pure/README;
  2344 
  2345 * improved the theory data mechanism to support encapsulation (data
  2346 kind name replaced by private Object.kind, acting as authorization
  2347 key); new type-safe user interface via functor TheoryDataFun; generic
  2348 print_data function becomes basically useless;
  2349 
  2350 * removed global_names compatibility flag -- all theory declarations
  2351 are qualified by default;
  2352 
  2353 * module Pure/Syntax now offers quote / antiquote translation
  2354 functions (useful for Hoare logic etc. with implicit dependencies);
  2355 see HOL/ex/Antiquote for an example use;
  2356 
  2357 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2358 cterm -> thm;
  2359 
  2360 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2361 subgoal;
  2362 
  2363 * Display.print_goals function moved to Locale.print_goals;
  2364 
  2365 * standard print function for goals supports current_goals_markers
  2366 variable for marking begin of proof, end of proof, start of goal; the
  2367 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2368 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2369 for example;
  2370 
  2371 
  2372 
  2373 New in Isabelle98 (January 1998)
  2374 --------------------------------
  2375 
  2376 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2377 
  2378 * changed lexical syntax of terms / types: dots made part of long
  2379 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2380 
  2381 * simpset (and claset) reference variable replaced by functions
  2382 simpset / simpset_ref;
  2383 
  2384 * no longer supports theory aliases (via merge) and non-trivial
  2385 implicit merge of thms' signatures;
  2386 
  2387 * most internal names of constants changed due to qualified names;
  2388 
  2389 * changed Pure/Sequence interface (see Pure/seq.ML);
  2390 
  2391 
  2392 *** General Changes ***
  2393 
  2394 * hierachically structured name spaces (for consts, types, axms, thms
  2395 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2396 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2397 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2398 long_names for fully qualified output names; NOTE: ML programs
  2399 (special tactics, packages etc.) referring to internal names may have
  2400 to be adapted to cope with fully qualified names; in case of severe
  2401 backward campatibility problems try setting 'global_names' at compile
  2402 time to have enrything declared within a flat name space; one may also
  2403 fine tune name declarations in theories via the 'global' and 'local'
  2404 section;
  2405 
  2406 * reimplemented the implicit simpset and claset using the new anytype
  2407 data filed in signatures; references simpset:simpset ref etc. are
  2408 replaced by functions simpset:unit->simpset and
  2409 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2410 to patch your ML files accordingly;
  2411 
  2412 * HTML output now includes theory graph data for display with Java
  2413 applet or isatool browser; data generated automatically via isatool
  2414 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2415 
  2416 * defs may now be conditional; improved rewrite_goals_tac to handle
  2417 conditional equations;
  2418 
  2419 * defs now admits additional type arguments, using TYPE('a) syntax;
  2420 
  2421 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2422 creates a new theory node; implicit merge of thms' signatures is
  2423 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2424 transfer:theory->thm->thm in (rare) cases;
  2425 
  2426 * improved handling of draft signatures / theories; draft thms (and
  2427 ctyps, cterms) are automatically promoted to real ones;
  2428 
  2429 * slightly changed interfaces for oracles: admit many per theory, named
  2430 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2431 
  2432 * print_goals: optional output of const types (set show_consts and
  2433 show_types);
  2434 
  2435 * improved output of warnings (###) and errors (***);
  2436 
  2437 * subgoal_tac displays a warning if the new subgoal has type variables;
  2438 
  2439 * removed old README and Makefiles;
  2440 
  2441 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2442 
  2443 * removed obsolete init_pps and init_database;
  2444 
  2445 * deleted the obsolete tactical STATE, which was declared by
  2446     fun STATE tacfun st = tacfun st st;
  2447 
  2448 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2449 (which abbreviates $HOME);
  2450 
  2451 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2452 use isatool fixseq to adapt your ML programs (this works for fully
  2453 qualified references to the Sequence structure only!);
  2454 
  2455 * use_thy no longer requires writable current directory; it always
  2456 reloads .ML *and* .thy file, if either one is out of date;
  2457 
  2458 
  2459 *** Classical Reasoner ***
  2460 
  2461 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2462 tactics that use classical reasoning to simplify a subgoal without
  2463 splitting it into several subgoals;
  2464 
  2465 * Safe_tac: like safe_tac but uses the default claset;
  2466 
  2467 
  2468 *** Simplifier ***
  2469 
  2470 * added simplification meta rules:
  2471     (asm_)(full_)simplify: simpset -> thm -> thm;
  2472 
  2473 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2474 logics (again);
  2475 
  2476 * added prems argument to simplification procedures;
  2477 
  2478 * HOL, FOL, ZF: added infix function `addsplits':
  2479   instead of `<simpset> setloop (split_tac <thms>)'
  2480   you can simply write `<simpset> addsplits <thms>'
  2481 
  2482 
  2483 *** Syntax ***
  2484 
  2485 * TYPE('a) syntax for type reflection terms;
  2486 
  2487 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2488 
  2489 * pretty printer: changed order of mixfix annotation preference (again!);
  2490 
  2491 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2492 
  2493 
  2494 *** HOL ***
  2495 
  2496 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2497   with `addloop' of the simplifier to faciliate case splitting in premises.
  2498 
  2499 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2500 
  2501 * HOL/Auth: new protocol proofs including some for the Internet
  2502   protocol TLS;
  2503 
  2504 * HOL/Map: new theory of `maps' a la VDM;
  2505 
  2506 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2507 cancelling out common nat summands from =, <, <= (in)equalities, or
  2508 differences; simplification procedures nat_cancel_factor for
  2509 cancelling common factor from =, <, <= (in)equalities over natural
  2510 sums; nat_cancel contains both kinds of procedures, it is installed by
  2511 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2512 
  2513 * HOL/simplifier: terms of the form
  2514   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2515   are rewritten to
  2516   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2517   and those of the form
  2518   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2519   are rewritten to
  2520   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2521 
  2522 * HOL/datatype
  2523   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2524 
  2525   P(t_case f1 ... fn x) =
  2526      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2527         ...
  2528        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2529      )
  2530 
  2531   and a theorem `split_t_case_asm' of the form
  2532 
  2533   P(t_case f1 ... fn x) =
  2534     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2535         ...
  2536        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2537      )
  2538   which can be added to a simpset via `addsplits'. The existing theorems
  2539   expand_list_case and expand_option_case have been renamed to
  2540   split_list_case and split_option_case.
  2541 
  2542 * HOL/Arithmetic:
  2543   - `pred n' is automatically converted to `n-1'.
  2544     Users are strongly encouraged not to use `pred' any longer,
  2545     because it will disappear altogether at some point.
  2546   - Users are strongly encouraged to write "0 < n" rather than
  2547     "n ~= 0". Theorems and proof tools have been modified towards this
  2548     `standard'.
  2549 
  2550 * HOL/Lists:
  2551   the function "set_of_list" has been renamed "set" (and its theorems too);
  2552   the function "nth" now takes its arguments in the reverse order and
  2553   has acquired the infix notation "!" as in "xs!n".
  2554 
  2555 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2556 
  2557 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2558   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2559 
  2560 * HOL/record: extensible records with schematic structural subtyping
  2561 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2562 still lacks various theorems and concrete record syntax;
  2563 
  2564 
  2565 *** HOLCF ***
  2566 
  2567 * removed "axioms" and "generated by" sections;
  2568 
  2569 * replaced "ops" section by extended "consts" section, which is capable of
  2570   handling the continuous function space "->" directly;
  2571 
  2572 * domain package:
  2573   . proves theorems immediately and stores them in the theory,
  2574   . creates hierachical name space,
  2575   . now uses normal mixfix annotations (instead of cinfix...),
  2576   . minor changes to some names and values (for consistency),
  2577   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2578   . separator between mutual domain defs: changed "," to "and",
  2579   . improved handling of sort constraints;  now they have to
  2580     appear on the left-hand side of the equations only;
  2581 
  2582 * fixed LAM <x,y,zs>.b syntax;
  2583 
  2584 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2585 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2586 
  2587 
  2588 *** FOL and ZF ***
  2589 
  2590 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2591   with `addloop' of the simplifier to faciliate case splitting in premises.
  2592 
  2593 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2594 in HOL, they strip ALL and --> from proved theorems;
  2595 
  2596 
  2597 
  2598 New in Isabelle94-8 (May 1997)
  2599 ------------------------------
  2600 
  2601 *** General Changes ***
  2602 
  2603 * new utilities to build / run / maintain Isabelle etc. (in parts
  2604 still somewhat experimental); old Makefiles etc. still functional;
  2605 
  2606 * new 'Isabelle System Manual';
  2607 
  2608 * INSTALL text, together with ./configure and ./build scripts;
  2609 
  2610 * reimplemented type inference for greater efficiency, better error
  2611 messages and clean internal interface;
  2612 
  2613 * prlim command for dealing with lots of subgoals (an easier way of
  2614 setting goals_limit);
  2615 
  2616 
  2617 *** Syntax ***
  2618 
  2619 * supports alternative (named) syntax tables (parser and pretty
  2620 printer); internal interface is provided by add_modesyntax(_i);
  2621 
  2622 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2623 be used in conjunction with the Isabelle symbol font; uses the
  2624 "symbols" syntax table;
  2625 
  2626 * added token_translation interface (may translate name tokens in
  2627 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2628 the current print_mode); IMPORTANT: user print translation functions
  2629 are responsible for marking newly introduced bounds
  2630 (Syntax.mark_boundT);
  2631 
  2632 * token translations for modes "xterm" and "xterm_color" that display
  2633 names in bold, underline etc. or colors (which requires a color
  2634 version of xterm);
  2635 
  2636 * infixes may now be declared with names independent of their syntax;
  2637 
  2638 * added typed_print_translation (like print_translation, but may
  2639 access type of constant);
  2640 
  2641 
  2642 *** Classical Reasoner ***
  2643 
  2644 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2645 some limitations.  Blast_tac...
  2646   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2647   + ignores elimination rules that don't have the correct format
  2648         (the conclusion MUST be a formula variable)
  2649   + ignores types, which can make HOL proofs fail
  2650   + rules must not require higher-order unification, e.g. apply_type in ZF
  2651     [message "Function Var's argument not a bound variable" relates to this]
  2652   + its proof strategy is more general but can actually be slower
  2653 
  2654 * substitution with equality assumptions no longer permutes other
  2655 assumptions;
  2656 
  2657 * minor changes in semantics of addafter (now called addaltern); renamed
  2658 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2659 (and access functions for it);
  2660 
  2661 * improved combination of classical reasoner and simplifier:
  2662   + functions for handling clasimpsets
  2663   + improvement of addss: now the simplifier is called _after_ the
  2664     safe steps.
  2665   + safe variant of addss called addSss: uses safe simplifications
  2666     _during_ the safe steps. It is more complete as it allows multiple
  2667     instantiations of unknowns (e.g. with slow_tac).
  2668 
  2669 *** Simplifier ***
  2670 
  2671 * added interface for simplification procedures (functions that
  2672 produce *proven* rewrite rules on the fly, depending on current
  2673 redex);
  2674 
  2675 * ordering on terms as parameter (used for ordered rewriting);
  2676 
  2677 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2678 
  2679 * the solver is now split into a safe and an unsafe part.
  2680 This should be invisible for the normal user, except that the
  2681 functions setsolver and addsolver have been renamed to setSolver and
  2682 addSolver; added safe_asm_full_simp_tac;
  2683 
  2684 
  2685 *** HOL ***
  2686 
  2687 * a generic induction tactic `induct_tac' which works for all datatypes and
  2688 also for type `nat';
  2689 
  2690 * a generic case distinction tactic `exhaust_tac' which works for all
  2691 datatypes and also for type `nat';
  2692 
  2693 * each datatype comes with a function `size';
  2694 
  2695 * patterns in case expressions allow tuple patterns as arguments to
  2696 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2697 
  2698 * primrec now also works with type nat;
  2699 
  2700 * recdef: a new declaration form, allows general recursive functions to be
  2701 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2702 
  2703 * the constant for negation has been renamed from "not" to "Not" to
  2704 harmonize with FOL, ZF, LK, etc.;
  2705 
  2706 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2707 infinite lists;
  2708 
  2709 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2710 
  2711 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2712 problems in commutative rings, using axiomatic type classes for + and *;
  2713 
  2714 * more examples in HOL/MiniML and HOL/Auth;
  2715 
  2716 * more default rewrite rules for quantifiers, union/intersection;
  2717 
  2718 * a new constant `arbitrary == @x.False';
  2719 
  2720 * HOLCF/IOA replaces old HOL/IOA;
  2721 
  2722 * HOLCF changes: derived all rules and arities
  2723   + axiomatic type classes instead of classes
  2724   + typedef instead of faking type definitions
  2725   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2726   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2727   + eliminated the types void, one, tr
  2728   + use unit lift and bool lift (with translations) instead of one and tr
  2729   + eliminated blift from Lift3.thy (use Def instead of blift)
  2730   all eliminated rules are derived as theorems --> no visible changes ;
  2731 
  2732 
  2733 *** ZF ***
  2734 
  2735 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2736 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2737 as ZF_cs addSIs [equalityI];
  2738 
  2739 
  2740 
  2741 New in Isabelle94-7 (November 96)
  2742 ---------------------------------
  2743 
  2744 * allowing negative levels (as offsets) in prlev and choplev;
  2745 
  2746 * super-linear speedup for large simplifications;
  2747 
  2748 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2749 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2750 FAIL); can suppress it using the command Delsimps (ex_simps @
  2751 all_simps); De Morgan laws are also now included, by default;
  2752 
  2753 * improved printing of ==>  :  ~:
  2754 
  2755 * new object-logic "Sequents" adds linear logic, while replacing LK
  2756 and Modal (thanks to Sara Kalvala);
  2757 
  2758 * HOL/Auth: correctness proofs for authentication protocols;
  2759 
  2760 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2761 examples on HOL/Auth);
  2762 
  2763 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2764 the rewriter and classical reasoner simultaneously;
  2765 
  2766 * function uresult no longer returns theorems in "standard" format;
  2767 regain previous version by: val uresult = standard o uresult;
  2768 
  2769 
  2770 
  2771 New in Isabelle94-6
  2772 -------------------
  2773 
  2774 * oracles -- these establish an interface between Isabelle and trusted
  2775 external reasoners, which may deliver results as theorems;
  2776 
  2777 * proof objects (in particular record all uses of oracles);
  2778 
  2779 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2780 
  2781 * "constdefs" section in theory files;
  2782 
  2783 * "primrec" section (HOL) no longer requires names;
  2784 
  2785 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2786 
  2787 
  2788 
  2789 New in Isabelle94-5
  2790 -------------------
  2791 
  2792 * reduced space requirements;
  2793 
  2794 * automatic HTML generation from theories;
  2795 
  2796 * theory files no longer require "..." (quotes) around most types;
  2797 
  2798 * new examples, including two proofs of the Church-Rosser theorem;
  2799 
  2800 * non-curried (1994) version of HOL is no longer distributed;
  2801 
  2802 
  2803 
  2804 New in Isabelle94-4
  2805 -------------------
  2806 
  2807 * greatly reduced space requirements;
  2808 
  2809 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2810 
  2811 * searchable theorem database (see the section "Retrieving theorems" on
  2812 page 8 of the Reference Manual);
  2813 
  2814 * new examples, including Grabczewski's monumental case study of the
  2815 Axiom of Choice;
  2816 
  2817 * The previous version of HOL renamed to Old_HOL;
  2818 
  2819 * The new version of HOL (previously called CHOL) uses a curried syntax
  2820 for functions.  Application looks like f a b instead of f(a,b);
  2821 
  2822 * Mutually recursive inductive definitions finally work in HOL;
  2823 
  2824 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2825 translates to the operator "split";
  2826 
  2827 
  2828 
  2829 New in Isabelle94-3
  2830 -------------------
  2831 
  2832 * new infix operator, addss, allowing the classical reasoner to
  2833 perform simplification at each step of its search.  Example:
  2834         fast_tac (cs addss ss)
  2835 
  2836 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2837 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2838 look like (a,b) instead of <a,b>;
  2839 
  2840 * PLEASE NOTE: CHOL will eventually replace HOL!
  2841 
  2842 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2843 It translates to the operator "split".  A new theory of integers is available;
  2844 
  2845 * In ZF, integer numerals now denote two's-complement binary integers.
  2846 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2847 
  2848 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2849 of the Axiom of Choice;
  2850 
  2851 
  2852 
  2853 New in Isabelle94-2
  2854 -------------------
  2855 
  2856 * Significantly faster resolution;
  2857 
  2858 * the different sections in a .thy file can now be mixed and repeated
  2859 freely;
  2860 
  2861 * Database of theorems for FOL, HOL and ZF.  New
  2862 commands including qed, qed_goal and bind_thm store theorems in the database.
  2863 
  2864 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2865 a given theory (thms_of), or find out what theory a theorem was proved in
  2866 (theory_of_thm);
  2867 
  2868 * Bugs fixed in the inductive definition and datatype packages;
  2869 
  2870 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2871 and HOL_dup_cs obsolete;
  2872 
  2873 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2874 have been removed;
  2875 
  2876 * Simpler definition of function space in ZF;
  2877 
  2878 * new results about cardinal and ordinal arithmetic in ZF;
  2879 
  2880 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2881 types;
  2882 
  2883 
  2884 $Id$