NEWS
author kleing
Wed May 18 10:51:15 2005 +0200 (2005-05-18)
changeset 16000 786c5f838b0c
parent 15979 c81578ac2d31
child 16013 3010430d894d
permissions -rw-r--r--
searching for combination of criteria (intro, elim, dest, name, pattern)
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Theory headers: the new header syntax for Isar theories is
    10 
    11   theory <name>
    12   imports <theory1> ... <theoryn>
    13   begin
    14 
    15   optionally also with a "files" section. The syntax
    16 
    17   theory <name> = <theory1> + ... + <theoryn>:
    18 
    19   will still be supported for some time but will eventually disappear.
    20   The syntax of old-style theories has not changed.
    21 
    22 * Theory loader: parent theories can now also be referred to via
    23   relative and absolute paths.
    24 
    25 * Provers/quasi.ML:  new transitivity reasoners for transitivity only
    26   and quasi orders.
    27 
    28 * Provers/trancl.ML:  new transitivity reasoner for transitive and
    29   reflexive-transitive closure of relations.
    30 
    31 * Provers/blast.ML:  new reference depth_limit to make blast's depth
    32   limit (previously hard-coded with a value of 20) user-definable.
    33 
    34 * Provers: new version of the subst method, for single-step rewriting: it now
    35   works in bound variable contexts. New is subst (asm), for rewriting an
    36   assumption. Thanks to Lucas Dixon! INCOMPATIBILITY: may rewrite a different
    37   subterm than the original subst method, which is still available under the
    38   name simplesubst.
    39 
    40 * Pure: thin_tac now works even if the assumption being deleted contains !! or ==>. 
    41   More generally, erule now works even if the major premise of the elimination rule
    42   contains !! or ==>.
    43 
    44 * Pure: considerably improved version of 'constdefs' command.  Now
    45   performs automatic type-inference of declared constants; additional
    46   support for local structure declarations (cf. locales and HOL
    47   records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    48   to observe strictly sequential dependencies of definitions within a
    49   single 'constdefs' section; moreover, the declared name needs to be
    50   an identifier.  If all fails, consider to fall back on 'consts' and
    51   'defs' separately.
    52 
    53 * Pure: improved indexed syntax and implicit structures.  First of
    54   all, indexed syntax provides a notational device for subscripted
    55   application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    56   expressions.  Secondly, in a local context with structure
    57   declarations, number indexes \<^sub>n or the empty index (default
    58   number 1) refer to a certain fixed variable implicitly; option
    59   show_structs controls printing of implicit structures.  Typical
    60   applications of these concepts involve record types and locales.
    61 
    62 * Pure: clear separation of logical types and nonterminals, where the
    63   latter may only occur in 'syntax' specifications or type
    64   abbreviations.  Before that distinction was only partially
    65   implemented via type class "logic" vs. "{}".  Potential
    66   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
    67   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
    68   specifications may require further adaption (e.g. Cube/Base.thy).
    69 
    70 * Pure: removed obsolete type class "logic", use the top sort {}
    71   instead.  Note that non-logical types should be declared as
    72   'nonterminals' rather than 'types'.  INCOMPATIBILITY for new
    73   object-logic specifications.
    74 
    75 * Pure: command 'no_syntax' removes grammar declarations (and
    76   translations) resulting from the given syntax specification, which
    77   is interpreted in the same manner as for the 'syntax' command.
    78 
    79 * Pure: print_tac now outputs the goal through the trace channel.
    80 
    81 * Pure: reference Namespace.unique_names included.  If true the
    82   (shortest) namespace-prefix is printed to disambiguate conflicts (as
    83   yet). If false the first entry wins (as during parsing). Default
    84   value is true.
    85 
    86 * Pure: tuned internal renaming of symbolic identifiers -- attach
    87   primes instead of base 26 numbers.
    88 
    89 * Pure: new flag show_question_marks controls printing of leading
    90   question marks in schematic variable names.
    91 
    92 * Pure: new version of thms_containing that searches for a list of
    93   criteria instead of a list of constants. Known criteria are: intro,
    94   elim, dest, name:string, and any term. Criteria can be preceded by
    95   '-' to select theorems that do not match. Intro, elim, dest select
    96   theorems that match the current goal, name:s selects theorems whose
    97   fully qualified name contain s.  Any other term is interpreted as
    98   pattern and selects all theorem matching the pattern. Available in
    99   ProofGeneral under ProofGeneral -> Find Theorems or C-c C-f.
   100 
   101   Example: C-c C-f (100) "(_::nat) + _ + _" intro -name:"HOL."
   102 
   103   prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   104   matching the current goal as introduction rule and not having "HOL." 
   105   in their name (i.e. not being defined in theory HOL).
   106 
   107 * Pure/Syntax: inner syntax includes (*(*nested*) comments*).
   108 
   109 * Pure/Syntax: pretty pinter now supports unbreakable blocks,
   110   specified in mixfix annotations as "(00...)".
   111 
   112 * Pure/Syntax: 'advanced' translation functions (parse_translation
   113   etc.) may depend on the signature of the theory context being
   114   presently used for parsing/printing, see also isar-ref manual.
   115 
   116 * Pure/Simplifier: simplification procedures may now take the current
   117   simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   118   interface), which is very useful for calling the Simplifier
   119   recursively.  Minor INCOMPATIBILITY: the 'prems' argument of
   120   simprocs is gone -- use prems_of_ss on the simpset instead.
   121   Moreover, the low-level mk_simproc no longer applies Logic.varify
   122   internally, to allow for use in a context of fixed variables.
   123 
   124 * Pure/Simplifier: Command "find_rewrites" takes a string and lists all
   125   equality theorems (not just those declared as simp!) whose left-hand
   126   side matches the term given via the string. In PG the command can be
   127   activated via Isabelle -> Show me -> matching rewrites.
   128 
   129 * Isar debugging: new reference Toplevel.debug; default false.
   130   Set to make printing of exceptions THM, TERM, TYPE and THEORY more verbose.
   131   
   132 * Locales:
   133   - "includes" disallowed in declaration of named locales (command "locale").
   134   - Fixed parameter management in theorem generation for goals with "includes".
   135     INCOMPATIBILITY: rarely, the generated theorem statement is different.
   136 
   137 * Locales:  new commands for the interpretation of locale expressions
   138   in theories (interpretation) and proof contexts (interpret).  These take an
   139   instantiation of the locale parameters and compute proof obligations from
   140   the instantiated specification.  After the obligations have been discharged,
   141   the instantiated theorems of the locale are added to the theory or proof
   142   context.  Interpretation is smart in that already active interpretations
   143   do not occur in proof obligations, neither are instantiated theorems stored
   144   in duplicate.
   145   Use print_interps to inspect active interpretations of a particular locale.
   146   For details, see the Isar Reference manual.
   147 
   148 * Locales: proper static binding of attribute syntax -- i.e. types /
   149   terms / facts mentioned as arguments are always those of the locale
   150   definition context, independently of the context of later
   151   invocations.  Moreover, locale operations (renaming and type / term
   152   instantiation) are applied to attribute arguments as expected.
   153 
   154   INCOMPATIBILITY of the ML interface: always pass Attrib.src instead
   155   of actual attributes; rare situations may require Attrib.attribute
   156   to embed those attributes into Attrib.src that lack concrete syntax.
   157 
   158   Attribute implementations need to cooperate properly with the static
   159   binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   160   Attrib.XXX_thm etc. already do the right thing without further
   161   intervention.  Only unusual applications -- such as "where" or "of"
   162   (cf. src/Pure/Isar/attrib.ML), which process arguments depending
   163   both on the context and the facts involved -- may have to assign
   164   parsed values to argument tokens explicitly.
   165 
   166 * Attributes 'induct' and 'cases': type or set names may now be
   167   locally fixed variables as well.
   168 
   169 * Isar: new syntax 'name(i-j, i-, i, ...)' for referring to specific
   170   selections of theorems in named facts via indices.
   171 
   172 * Pure: reorganized bootstrapping of the Pure theories; CPure is now
   173   derived from Pure, which contains all common declarations already.
   174   Both theories are defined via plain Isabelle/Isar .thy files.
   175   INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   176   CPure.elim / CPure.dest attributes) now appear in the Pure name
   177   space; use isatool fixcpure to adapt your theory and ML sources.
   178 
   179 
   180 *** Document preparation ***
   181 
   182 * Several new antiquotation:
   183 
   184   @{term_type term} prints a term with its type annotated;
   185 
   186   @{typeof term} prints the type of a term;
   187 
   188   @{const const} is the same as @{term const}, but checks
   189     that the argument is a known logical constant;
   190 
   191   @{term_style style term} and @{thm_style style thm} print a term or
   192     theorem applying a "style" to it
   193 
   194   Predefined styles are "lhs" and "rhs" printing the lhs/rhs of
   195   definitions, equations, inequations etc. and "conclusion" printing
   196   only the conclusion of a meta-logical statement theorem.  Styles may
   197   be defined via TermStyle.add_style in ML.  See the "LaTeX Sugar"
   198   document for more information.
   199 
   200 * Antiquotations now provide the option 'locale=NAME' to specify an
   201   alternative context used for evaluating and printing the subsequent
   202   argument, as in @{thm [locale=LC] fold_commute}, for example.
   203 
   204 * Commands 'display_drafts' and 'print_drafts' perform simple output
   205   of raw sources.  Only those symbols that do not require additional
   206   LaTeX packages (depending on comments in isabellesym.sty) are
   207   displayed properly, everything else is left verbatim.  We use
   208   isatool display and isatool print as front ends; these are subject
   209   to the DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively.
   210 
   211 * Proof scripts as well as some other commands such as ML or
   212   parse/print_translation can now be hidden in the document.  Hiding
   213   is enabled by default, and can be disabled either via the option '-H
   214   false' of isatool usedir or by resetting the reference variable
   215   IsarOutput.hide_commands. Additional commands to be hidden may be
   216   declared using IsarOutput.add_hidden_commands.
   217 
   218 
   219 *** HOL ***
   220 
   221 * Datatype induction via method `induct' now preserves the name of the
   222   induction variable. For example, when proving P(xs::'a list) by induction
   223   on xs, the induction step is now P(xs) ==> P(a#xs) rather than
   224   P(list) ==> P(a#list) as previously.
   225 
   226 * HOL/record: reimplementation of records. Improved scalability for
   227   records with many fields, avoiding performance problems for type
   228   inference. Records are no longer composed of nested field types, but
   229   of nested extension types. Therefore the record type only grows
   230   linear in the number of extensions and not in the number of fields.
   231   The top-level (users) view on records is preserved.  Potential
   232   INCOMPATIBILITY only in strange cases, where the theory depends on
   233   the old record representation. The type generated for a record is
   234   called <record_name>_ext_type.
   235 
   236 * HOL/record: Reference record_quick_and_dirty_sensitive can be
   237   enabled to skip the proofs triggered by a record definition or a
   238   simproc (if quick_and_dirty is enabled). Definitions of large
   239   records can take quite long.
   240 
   241 * HOL/record: "record_upd_simproc" for simplification of multiple
   242   record updates enabled by default.  Moreover, trivial updates are
   243   also removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   244   occasionally, since simplification is more powerful by default.
   245 
   246 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
   247 
   248   syntax (epsilon)
   249     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   250 
   251   The symbol \<some> is displayed as the alternative epsilon of LaTeX
   252   and x-symbol; use option '-m epsilon' to get it actually printed.
   253   Moreover, the mathematically important symbolic identifier
   254   \<epsilon> becomes available as variable, constant etc.
   255 
   256 * HOL: "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   257   Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   258   is \<ge>.
   259 
   260 * HOL/Set: "{x:A. P}" abbreviates "{x. x:A & P}" (and similarly for
   261   "\<in>" instead of ":").
   262 
   263 * HOL/SetInterval: The syntax for open intervals has changed:
   264 
   265   Old         New
   266   {..n(}   -> {..<n}
   267   {)n..}   -> {n<..}
   268   {m..n(}  -> {m..<n}
   269   {)m..n}  -> {m<..n}
   270   {)m..n(} -> {m<..<n}
   271 
   272   The old syntax is still supported but will disappear in the future.
   273   For conversion use the following emacs search and replace patterns:
   274 
   275   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   276   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   277 
   278   They are not perfect but work quite well.
   279 
   280 * HOL: The syntax for 'setsum', summation over finite sets, has changed:
   281 
   282   The syntax for 'setsum (%x. e) A' used to be '\<Sum>x:A. e'
   283   and is now either 'SUM x:A. e' or '\<Sum>x\<in>A. e'.
   284 
   285   There is new syntax for summation over finite sets:
   286 
   287   '\<Sum>x | P. e'    is the same as  'setsum (%x. e) {x. P}'
   288   '\<Sum>x=a..b. e'   is the same as  'setsum (%x. e) {a..b}'
   289   '\<Sum>x=a..<b. e'  is the same as  'setsum (%x. e) {a..<b}'
   290   '\<Sum>x<k. e'      is the same as  'setsum (%x. e) {..<k}'
   291 
   292   Function 'Summation' over nat is gone, its syntax '\<Sum>i<k. e'
   293   now translates into 'setsum' as above.
   294 
   295 * HOL: Finite set induction: In Isar proofs, the insert case is now
   296   "case (insert x F)" instead of the old counterintuitive "case (insert F x)".
   297 
   298 * HOL/Simplifier:
   299 
   300   - Is now set up to reason about transitivity chains involving "trancl"
   301   (r^+) and "rtrancl" (r^*) by setting up tactics provided by
   302   Provers/trancl.ML as additional solvers.  INCOMPATIBILITY: old proofs break
   303   occasionally as simplification may now solve more goals than previously.
   304 
   305   - Converts x <= y into x = y if assumption y <= x is present.  Works for
   306   all partial orders (class "order"), in particular numbers and sets. For
   307   linear orders (e.g. numbers) it treats ~ x < y just like y <= x.
   308 
   309   - Simproc for "let x = a in f x"
   310   If a is a free or bound variable or a constant then the let is unfolded.
   311   Otherwise first a is simplified to a', and then f a' is simplified to
   312   g. If possible we abstract a' from g arriving at "let x = a' in g' x",
   313   otherwise we unfold the let and arrive at g. The simproc can be 
   314   enabled/disabled by the reference use_let_simproc. Potential
   315   INCOMPATIBILITY since simplification is more powerful by default.
   316 
   317 * HOL: The 'refute' command has been extended to support a much larger
   318   fragment of HOL, including axiomatic type classes, constdefs and typedefs,
   319   inductive datatypes and recursion.
   320 
   321 
   322 *** HOLCF ***
   323 
   324 * HOLCF: discontinued special version of 'constdefs' (which used to
   325   support continuous functions) in favor of the general Pure one with
   326   full type-inference.
   327 
   328 
   329 *** ZF ***
   330 
   331 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the
   332   First Isomorphism Theorem (on quotienting by the kernel of a
   333   homomorphism).
   334 
   335 * ZF/Simplifier: install second copy of type solver that actually
   336   makes use of TC rules declared to Isar proof contexts (or locales);
   337   the old version is still required for ML proof scripts.
   338 
   339 
   340 *** System ***
   341 
   342 * Allow symlinks to all proper Isabelle executables (Isabelle,
   343   isabelle, isatool etc.).
   344 
   345 * isabelle-process: Poly/ML no longer needs Perl to run an interactive
   346   session.
   347 
   348 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   349   isatool doc, isatool mkdir, display_drafts etc.).
   350 
   351 * isatool usedir: option -f allows specification of the ML file to be
   352   used by Isabelle; default is ROOT.ML.
   353 
   354 * HOL: isatool dimacs2hol converts files in DIMACS CNF format
   355   (containing Boolean satisfiability problems) into Isabelle/HOL
   356   theories.
   357 
   358 
   359 *** ML ***
   360 
   361 * Pure/library.ML no longer defines its own option datatype, but uses
   362   that of the SML basis, which has constructors NONE and SOME instead
   363   of None and Some, as well as exception Option.Option instead of
   364   OPTION.  The functions the, if_none, is_some, is_none have been
   365   adapted accordingly, while Option.map replaces apsome.
   366 
   367 * The exception LIST is no more, the standard exceptions Empty and
   368   Subscript, as well as Library.UnequalLengths are used instead.  This
   369   means that function like Library.hd and Library.tl are gone, as the
   370   standard hd and tl functions suffice.
   371 
   372   A number of basic functions are now no longer exported to the ML
   373   toplevel, as they are variants of standard functions.  The following
   374   suggests how one can translate existing code:
   375 
   376     rev_append xs ys = List.revAppend (xs, ys)
   377     nth_elem (i, xs) = List.nth (xs, i)
   378     last_elem xs = List.last xs
   379     flat xss = List.concat xss
   380     seq fs = app fs
   381     partition P xs = List.partition P xs
   382     filter P xs = List.filter P xs
   383     mapfilter f xs = List.mapPartial f xs
   384 
   385 * Pure: output via the Isabelle channels of writeln/warning/error
   386   etc. is now passed through Output.output, with a hook for arbitrary
   387   transformations depending on the print_mode (cf. Output.add_mode --
   388   the first active mode that provides a output function wins).
   389   Already formatted output may be embedded into further text via
   390   Output.raw; the result of Pretty.string_of/str_of and derived
   391   functions (string_of_term/cterm/thm etc.) is already marked raw to
   392   accommodate easy composition of diagnostic messages etc.
   393   Programmers rarely need to care about Output.output or Output.raw at
   394   all, with some notable exceptions: Output.output is required when
   395   bypassing the standard channels (writeln etc.), or in token
   396   translations to produce properly formatted results; Output.raw is
   397   required when capturing already output material that will eventually
   398   be presented to the user a second time.  For the default print mode,
   399   both Output.output and Output.raw have no effect.
   400 
   401 * Provers: Simplifier and Classical Reasoner now support proof context
   402   dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   403   components are stored in the theory and patched into the
   404   simpset/claset when used in an Isar proof context.  Context
   405   dependent components are maintained by the following theory
   406   operations:
   407 
   408     Simplifier.add_context_simprocs
   409     Simplifier.del_context_simprocs
   410     Simplifier.set_context_subgoaler
   411     Simplifier.reset_context_subgoaler
   412     Simplifier.add_context_looper
   413     Simplifier.del_context_looper
   414     Simplifier.add_context_unsafe_solver
   415     Simplifier.add_context_safe_solver
   416 
   417     Classical.add_context_safe_wrapper
   418     Classical.del_context_safe_wrapper
   419     Classical.add_context_unsafe_wrapper
   420     Classical.del_context_unsafe_wrapper
   421 
   422   IMPORTANT NOTE: proof tools (methods etc.) need to use
   423   local_simpset_of and local_claset_of to instead of the primitive
   424   Simplifier.get_local_simpset and Classical.get_local_claset,
   425   respectively, in order to see the context dependent fields!
   426 
   427 
   428 
   429 New in Isabelle2004 (April 2004)
   430 --------------------------------
   431 
   432 *** General ***
   433 
   434 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   435   Replaces linorder.ML.
   436 
   437 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   438   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   439   (\<a>...\<z>), are now considered normal letters, and can therefore
   440   be used anywhere where an ASCII letter (a...zA...Z) has until
   441   now. COMPATIBILITY: This obviously changes the parsing of some
   442   terms, especially where a symbol has been used as a binder, say
   443   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   444   as an identifier.  Fix it by inserting a space around former
   445   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   446   existing theory and ML files.
   447 
   448 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   449 
   450 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   451   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   452   a normal (but invisible) letter. For multiple letter subscripts repeat
   453   \<^isub> like this: x\<^isub>1\<^isub>2.
   454 
   455 * Pure: There are now sub-/superscripts that can span more than one
   456   character. Text between \<^bsub> and \<^esub> is set in subscript in
   457   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   458   superscript. The new control characters are not identifier parts.
   459 
   460 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   461   content of "..." to the latex file instead of \isacntrl... . The "..."
   462   may consist of any printable characters excluding the end bracket >.
   463 
   464 * Pure: Using new Isar command "finalconsts" (or the ML functions
   465   Theory.add_finals or Theory.add_finals_i) it is now possible to
   466   declare constants "final", which prevents their being given a definition
   467   later.  It is useful for constants whose behaviour is fixed axiomatically
   468   rather than definitionally, such as the meta-logic connectives.
   469 
   470 * Pure: 'instance' now handles general arities with general sorts
   471   (i.e. intersections of classes),
   472 
   473 * Presentation: generated HTML now uses a CSS style sheet to make layout
   474   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   475   It can be changed to alter the colors/layout of generated pages.
   476 
   477 
   478 *** Isar ***
   479 
   480 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   481   cut_tac, subgoal_tac and thin_tac:
   482   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   483     locales are no longer forced to write Isar proof scripts.
   484     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   485     emulations.
   486   - INCOMPATIBILITY: names of variables to be instantiated may no
   487     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   488     This is consistent with the instantiation attribute "where".
   489 
   490 * Attributes "where" and "of":
   491   - Now take type variables of instantiated theorem into account when reading
   492     the instantiation string.  This fixes a bug that caused instantiated
   493     theorems to have too special types in some circumstances.
   494   - "where" permits explicit instantiations of type variables.
   495 
   496 * Calculation commands "moreover" and "also" no longer interfere with
   497   current facts ("this"), admitting arbitrary combinations with "then"
   498   and derived forms.
   499 
   500 * Locales:
   501   - Goal statements involving the context element "includes" no longer
   502     generate theorems with internal delta predicates (those ending on
   503     "_axioms") in the premise.
   504     Resolve particular premise with <locale>.intro to obtain old form.
   505   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   506     specification and "includes" elements in goal statement.
   507   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   508     [intro?] and [elim?] (respectively) by default.
   509   - Experimental command for instantiation of locales in proof contexts:
   510         instantiate <label>[<attrs>]: <loc>
   511     Instantiates locale <loc> and adds all its theorems to the current context
   512     taking into account their attributes.  Label and attrs are optional
   513     modifiers, like in theorem declarations.  If present, names of
   514     instantiated theorems are qualified with <label>, and the attributes
   515     <attrs> are applied after any attributes these theorems might have already.
   516       If the locale has assumptions, a chained fact of the form
   517     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   518     are derived.  The command does not support old-style locales declared
   519     with "locale (open)".
   520       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   521 
   522 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   523   (Isar) contexts.
   524 
   525 
   526 *** HOL ***
   527 
   528 * Proof import: new image HOL4 contains the imported library from
   529   the HOL4 system with about 2500 theorems. It is imported by
   530   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   531   can be used like any other Isabelle image.  See
   532   HOL/Import/HOL/README for more information.
   533 
   534 * Simplifier:
   535   - Much improved handling of linear and partial orders.
   536     Reasoners for linear and partial orders are set up for type classes
   537     "linorder" and "order" respectively, and are added to the default simpset
   538     as solvers.  This means that the simplifier can build transitivity chains
   539     to solve goals from the assumptions.
   540   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   541     of blast or auto after simplification become unnecessary because the goal
   542     is solved by simplification already.
   543 
   544 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   545     all proved in axiomatic type classes for semirings, rings and fields.
   546 
   547 * Numerics:
   548   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   549     now formalized using the Ring_and_Field theory mentioned above.
   550   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   551     than before, because now they are set up once in a generic manner.
   552   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   553     Look for the general versions in Ring_and_Field (and Power if they concern
   554     exponentiation).
   555 
   556 * Type "rat" of the rational numbers is now available in HOL-Complex.
   557 
   558 * Records:
   559   - Record types are now by default printed with their type abbreviation
   560     instead of the list of all field types. This can be configured via
   561     the reference "print_record_type_abbr".
   562   - Simproc "record_upd_simproc" for simplification of multiple updates added
   563     (not enabled by default).
   564   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   565     EX x. x = sel r to True (not enabled by default).
   566   - Tactic "record_split_simp_tac" to split and simplify records added.
   567 
   568 * 'specification' command added, allowing for definition by
   569   specification.  There is also an 'ax_specification' command that
   570   introduces the new constants axiomatically.
   571 
   572 * arith(_tac) is now able to generate counterexamples for reals as well.
   573 
   574 * HOL-Algebra: new locale "ring" for non-commutative rings.
   575 
   576 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   577   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   578 
   579 * HOL-Matrix: a first theory for matrices in HOL with an application of
   580   matrix theory to linear programming.
   581 
   582 * Unions and Intersections:
   583   The latex output syntax of UN and INT has been changed
   584   from "\Union x \in A. B" to "\Union_{x \in A} B"
   585   i.e. the index formulae has become a subscript.
   586   Similarly for "\Union x. B", and for \Inter instead of \Union.
   587 
   588 * Unions and Intersections over Intervals:
   589   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   590   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   591   like in normal math, and corresponding versions for < and for intersection.
   592 
   593 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   594   lexicographic dictonary ordering has been added as "lexord".
   595 
   596 * ML: the legacy theory structures Int and List have been removed. They had
   597   conflicted with ML Basis Library structures having the same names.
   598 
   599 * 'refute' command added to search for (finite) countermodels.  Only works
   600   for a fragment of HOL.  The installation of an external SAT solver is
   601   highly recommended.  See "HOL/Refute.thy" for details.
   602 
   603 * 'quickcheck' command: Allows to find counterexamples by evaluating
   604   formulae under an assignment of free variables to random values.
   605   In contrast to 'refute', it can deal with inductive datatypes,
   606   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   607   for examples.
   608 
   609 
   610 *** HOLCF ***
   611 
   612 * Streams now come with concatenation and are part of the HOLCF image
   613 
   614 
   615 
   616 New in Isabelle2003 (May 2003)
   617 ------------------------------
   618 
   619 *** General ***
   620 
   621 * Provers/simplifier:
   622 
   623   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   624     Assumptions are now subject to complete mutual simplification,
   625     not just from left to right. The simplifier now preserves
   626     the order of assumptions.
   627 
   628     Potential INCOMPATIBILITY:
   629 
   630     -- simp sometimes diverges where the old version did
   631        not, e.g. invoking simp on the goal
   632 
   633         [| P (f x); y = x; f x = f y |] ==> Q
   634 
   635        now gives rise to the infinite reduction sequence
   636 
   637         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   638 
   639        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   640        kind of problem.
   641 
   642     -- Tactics combining classical reasoner and simplification (such as auto)
   643        are also affected by this change, because many of them rely on
   644        simp. They may sometimes diverge as well or yield a different numbers
   645        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   646        in case of problems. Sometimes subsequent calls to the classical
   647        reasoner will fail because a preceeding call to the simplifier too
   648        eagerly simplified the goal, e.g. deleted redundant premises.
   649 
   650   - The simplifier trace now shows the names of the applied rewrite rules
   651 
   652   - You can limit the number of recursive invocations of the simplifier
   653     during conditional rewriting (where the simplifie tries to solve the
   654     conditions before applying the rewrite rule):
   655     ML "simp_depth_limit := n"
   656     where n is an integer. Thus you can force termination where previously
   657     the simplifier would diverge.
   658 
   659   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   660 
   661   - No longer aborts on failed congruence proof.  Instead, the
   662     congruence is ignored.
   663 
   664 * Pure: New generic framework for extracting programs from constructive
   665   proofs. See HOL/Extraction.thy for an example instantiation, as well
   666   as HOL/Extraction for some case studies.
   667 
   668 * Pure: The main goal of the proof state is no longer shown by default, only
   669 the subgoals. This behaviour is controlled by a new flag.
   670    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   671 (ML: Proof.show_main_goal).
   672 
   673 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   674 rules whose conclusion matches subgoal 1:
   675       PG menu: Isabelle/Isar -> Show me -> matching rules
   676 The rules are ordered by how closely they match the subgoal.
   677 In particular, rules that solve a subgoal outright are displayed first
   678 (or rather last, the way they are printed).
   679 (ML: ProofGeneral.print_intros())
   680 
   681 * Pure: New flag trace_unify_fail causes unification to print
   682 diagnostic information (PG: in trace buffer) when it fails. This is
   683 useful for figuring out why single step proofs like rule, erule or
   684 assumption failed.
   685 
   686 * Pure: Locale specifications now produce predicate definitions
   687 according to the body of text (covering assumptions modulo local
   688 definitions); predicate "loc_axioms" covers newly introduced text,
   689 while "loc" is cumulative wrt. all included locale expressions; the
   690 latter view is presented only on export into the global theory
   691 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   692 on the old view without predicates;
   693 
   694 * Pure: predefined locales "var" and "struct" are useful for sharing
   695 parameters (as in CASL, for example); just specify something like
   696 ``var x + var y + struct M'' as import;
   697 
   698 * Pure: improved thms_containing: proper indexing of facts instead of
   699 raw theorems; check validity of results wrt. current name space;
   700 include local facts of proof configuration (also covers active
   701 locales), cover fixed variables in index; may use "_" in term
   702 specification; an optional limit for the number of printed facts may
   703 be given (the default is 40);
   704 
   705 * Pure: disallow duplicate fact bindings within new-style theory files
   706 (batch-mode only);
   707 
   708 * Provers: improved induct method: assumptions introduced by case
   709 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   710 the goal statement); "foo" still refers to all facts collectively;
   711 
   712 * Provers: the function blast.overloaded has been removed: all constants
   713 are regarded as potentially overloaded, which improves robustness in exchange
   714 for slight decrease in efficiency;
   715 
   716 * Provers/linorder: New generic prover for transitivity reasoning over
   717 linear orders.  Note: this prover is not efficient!
   718 
   719 * Isar: preview of problems to finish 'show' now produce an error
   720 rather than just a warning (in interactive mode);
   721 
   722 
   723 *** HOL ***
   724 
   725 * arith(_tac)
   726 
   727  - Produces a counter example if it cannot prove a goal.
   728    Note that the counter example may be spurious if the goal is not a formula
   729    of quantifier-free linear arithmetic.
   730    In ProofGeneral the counter example appears in the trace buffer.
   731 
   732  - Knows about div k and mod k where k is a numeral of type nat or int.
   733 
   734  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   735    linear arithmetic fails. This takes account of quantifiers and divisibility.
   736    Presburger arithmetic can also be called explicitly via presburger(_tac).
   737 
   738 * simp's arithmetic capabilities have been enhanced a bit: it now
   739 takes ~= in premises into account (by performing a case split);
   740 
   741 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   742 are distributed over a sum of terms;
   743 
   744 * New tactic "trans_tac" and method "trans" instantiate
   745 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   746 "<=", "<" and "=").
   747 
   748 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   749 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   750 
   751 * 'typedef' command has new option "open" to suppress the set
   752 definition;
   753 
   754 * functions Min and Max on finite sets have been introduced (theory
   755 Finite_Set);
   756 
   757 * attribute [symmetric] now works for relations as well; it turns
   758 (x,y) : R^-1 into (y,x) : R, and vice versa;
   759 
   760 * induct over a !!-quantified statement (say !!x1..xn):
   761   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   762 
   763 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   764 %x. None. Warning: empty_def now refers to the previously hidden definition
   765 of the empty set.
   766 
   767 * Algebra: formalization of classical algebra.  Intended as base for
   768 any algebraic development in Isabelle.  Currently covers group theory
   769 (up to Sylow's theorem) and ring theory (Universal Property of
   770 Univariate Polynomials).  Contributions welcome;
   771 
   772 * GroupTheory: deleted, since its material has been moved to Algebra;
   773 
   774 * Complex: new directory of the complex numbers with numeric constants,
   775 nonstandard complex numbers, and some complex analysis, standard and
   776 nonstandard (Jacques Fleuriot);
   777 
   778 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   779 
   780 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   781 Fleuriot);
   782 
   783 * Real/HahnBanach: updated and adapted to locales;
   784 
   785 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   786 Gray and Kramer);
   787 
   788 * UNITY: added the Meier-Sanders theory of progress sets;
   789 
   790 * MicroJava: bytecode verifier and lightweight bytecode verifier
   791 as abstract algorithms, instantiated to the JVM;
   792 
   793 * Bali: Java source language formalization. Type system, operational
   794 semantics, axiomatic semantics. Supported language features:
   795 classes, interfaces, objects,virtual methods, static methods,
   796 static/instance fields, arrays, access modifiers, definite
   797 assignment, exceptions.
   798 
   799 
   800 *** ZF ***
   801 
   802 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   803 universe, etc.);
   804 
   805 * Main ZF: virtually all theories converted to new-style format;
   806 
   807 
   808 *** ML ***
   809 
   810 * Pure: Tactic.prove provides sane interface for internal proofs;
   811 omits the infamous "standard" operation, so this is more appropriate
   812 than prove_goalw_cterm in many situations (e.g. in simprocs);
   813 
   814 * Pure: improved error reporting of simprocs;
   815 
   816 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   817 up simprocs;
   818 
   819 
   820 *** Document preparation ***
   821 
   822 * uses \par instead of \\ for line breaks in theory text. This may
   823 shift some page breaks in large documents. To get the old behaviour
   824 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   825 
   826 * minimized dependencies of isabelle.sty and isabellesym.sty on
   827 other packages
   828 
   829 * \<euro> now needs package babel/greek instead of marvosym (which
   830 broke \Rightarrow)
   831 
   832 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   833 textcomp package)
   834 
   835 
   836 
   837 New in Isabelle2002 (March 2002)
   838 --------------------------------
   839 
   840 *** Document preparation ***
   841 
   842 * greatly simplified document preparation setup, including more
   843 graceful interpretation of isatool usedir -i/-d/-D options, and more
   844 instructive isatool mkdir; users should basically be able to get
   845 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   846 users may run a separate document processing stage manually like this:
   847 "isatool usedir -D output HOL Test && isatool document Test/output";
   848 
   849 * theory dependency graph may now be incorporated into documents;
   850 isatool usedir -g true will produce session_graph.eps/.pdf for use
   851 with \includegraphics of LaTeX;
   852 
   853 * proper spacing of consecutive markup elements, especially text
   854 blocks after section headings;
   855 
   856 * support bold style (for single symbols only), input syntax is like
   857 this: "\<^bold>\<alpha>" or "\<^bold>A";
   858 
   859 * \<bullet> is now output as bold \cdot by default, which looks much
   860 better in printed text;
   861 
   862 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   863 note that these symbols are currently unavailable in Proof General /
   864 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   865 
   866 * isatool latex no longer depends on changed TEXINPUTS, instead
   867 isatool document copies the Isabelle style files to the target
   868 location;
   869 
   870 
   871 *** Isar ***
   872 
   873 * Pure/Provers: improved proof by cases and induction;
   874   - 'case' command admits impromptu naming of parameters (such as
   875     "case (Suc n)");
   876   - 'induct' method divinates rule instantiation from the inductive
   877     claim; no longer requires excessive ?P bindings for proper
   878     instantiation of cases;
   879   - 'induct' method properly enumerates all possibilities of set/type
   880     rules; as a consequence facts may be also passed through *type*
   881     rules without further ado;
   882   - 'induct' method now derives symbolic cases from the *rulified*
   883     rule (before it used to rulify cases stemming from the internal
   884     atomized version); this means that the context of a non-atomic
   885     statement becomes is included in the hypothesis, avoiding the
   886     slightly cumbersome show "PROP ?case" form;
   887   - 'induct' may now use elim-style induction rules without chaining
   888     facts, using ``missing'' premises from the goal state; this allows
   889     rules stemming from inductive sets to be applied in unstructured
   890     scripts, while still benefitting from proper handling of non-atomic
   891     statements; NB: major inductive premises need to be put first, all
   892     the rest of the goal is passed through the induction;
   893   - 'induct' proper support for mutual induction involving non-atomic
   894     rule statements (uses the new concept of simultaneous goals, see
   895     below);
   896   - append all possible rule selections, but only use the first
   897     success (no backtracking);
   898   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   899   - undeclared rule case names default to numbers 1, 2, 3, ...;
   900   - added 'print_induct_rules' (covered by help item in recent Proof
   901     General versions);
   902   - moved induct/cases attributes to Pure, methods to Provers;
   903   - generic method setup instantiated for FOL and HOL;
   904 
   905 * Pure: support multiple simultaneous goal statements, for example
   906 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   907 meta-level mechanism, this acts as if several individual goals had
   908 been stated separately; in particular common proof methods need to be
   909 repeated in order to cover all claims; note that a single elimination
   910 step is *not* sufficient to establish the two conjunctions, so this
   911 fails:
   912 
   913   assume "A & B" then have A and B ..   (*".." fails*)
   914 
   915 better use "obtain" in situations as above; alternative refer to
   916 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   917 
   918 * Pure: proper integration with ``locales''; unlike the original
   919 version by Florian Kammller, Isar locales package high-level proof
   920 contexts rather than raw logical ones (e.g. we admit to include
   921 attributes everywhere); operations on locales include merge and
   922 rename; support for implicit arguments (``structures''); simultaneous
   923 type-inference over imports and text; see also HOL/ex/Locales.thy for
   924 some examples;
   925 
   926 * Pure: the following commands have been ``localized'', supporting a
   927 target locale specification "(in name)": 'lemma', 'theorem',
   928 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   929 stored both within the locale and at the theory level (exported and
   930 qualified by the locale name);
   931 
   932 * Pure: theory goals may now be specified in ``long'' form, with
   933 ad-hoc contexts consisting of arbitrary locale elements. for example
   934 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   935 definitions may be given, too); the result is a meta-level rule with
   936 the context elements being discharged in the obvious way;
   937 
   938 * Pure: new proof command 'using' allows to augment currently used
   939 facts after a goal statement ('using' is syntactically analogous to
   940 'apply', but acts on the goal's facts only); this allows chained facts
   941 to be separated into parts given before and after a claim, as in
   942 ``from a and b have C using d and e <proof>'';
   943 
   944 * Pure: renamed "antecedent" case to "rule_context";
   945 
   946 * Pure: new 'judgment' command records explicit information about the
   947 object-logic embedding (used by several tools internally); no longer
   948 use hard-wired "Trueprop";
   949 
   950 * Pure: added 'corollary' command;
   951 
   952 * Pure: fixed 'token_translation' command;
   953 
   954 * Pure: removed obsolete 'exported' attribute;
   955 
   956 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   957 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   958 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   959 
   960 * Pure: method 'atomize' presents local goal premises as object-level
   961 statements (atomic meta-level propositions); setup controlled via
   962 rewrite rules declarations of 'atomize' attribute; example
   963 application: 'induct' method with proper rule statements in improper
   964 proof *scripts*;
   965 
   966 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   967 now consider the syntactic context of assumptions, giving a better
   968 chance to get type-inference of the arguments right (this is
   969 especially important for locales);
   970 
   971 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   972 mode;
   973 
   974 * Pure/obtain: the formal conclusion "thesis", being marked as
   975 ``internal'', may no longer be reference directly in the text;
   976 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   977 situations;
   978 
   979 * Pure: generic 'sym' attribute which declares a rule both as pure
   980 'elim?' and for the 'symmetric' operation;
   981 
   982 * Pure: marginal comments ``--'' may now occur just anywhere in the
   983 text; the fixed correlation with particular command syntax has been
   984 discontinued;
   985 
   986 * Pure: new method 'rules' is particularly well-suited for proof
   987 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   988 but often produces more compact proof terms with less detours;
   989 
   990 * Pure/Provers/classical: simplified integration with pure rule
   991 attributes and methods; the classical "intro?/elim?/dest?"
   992 declarations coincide with the pure ones; the "rule" method no longer
   993 includes classically swapped intros; "intro" and "elim" methods no
   994 longer pick rules from the context; also got rid of ML declarations
   995 AddXIs/AddXEs/AddXDs; all of this has some potential for
   996 INCOMPATIBILITY;
   997 
   998 * Provers/classical: attribute 'swapped' produces classical inversions
   999 of introduction rules;
  1000 
  1001 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1002 rules instead of full simplifier context; 'iff' attribute handles
  1003 conditional rules;
  1004 
  1005 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1006 
  1007 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1008 "(permissive)" option to recover old behavior;
  1009 
  1010 * HOL: 'inductive' no longer features separate (collective) attributes
  1011 for 'intros' (was found too confusing);
  1012 
  1013 * HOL: properly declared induction rules less_induct and
  1014 wf_induct_rule;
  1015 
  1016 
  1017 *** HOL ***
  1018 
  1019 * HOL: moved over to sane numeral syntax; the new policy is as
  1020 follows:
  1021 
  1022   - 0 and 1 are polymorphic constants, which are defined on any
  1023   numeric type (nat, int, real etc.);
  1024 
  1025   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1026   binary representation internally;
  1027 
  1028   - type nat has special constructor Suc, and generally prefers Suc 0
  1029   over 1::nat and Suc (Suc 0) over 2::nat;
  1030 
  1031 This change may cause significant problems of INCOMPATIBILITY; here
  1032 are some hints on converting existing sources:
  1033 
  1034   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1035   entities, so expressions involving "-" (unary or binary minus) need
  1036   to be spaced properly;
  1037 
  1038   - existing occurrences of "1" may need to be constraint "1::nat" or
  1039   even replaced by Suc 0; similar for old "2";
  1040 
  1041   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1042 
  1043   - remove all special provisions on numerals in proofs;
  1044 
  1045 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1046 representation (depends on bin_arith_simps in the default context);
  1047 
  1048 * HOL: symbolic syntax for x^2 (numeral 2);
  1049 
  1050 * HOL: the class of all HOL types is now called "type" rather than
  1051 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1052 in axclass/classes, instance/arities, and (usually rare) occurrences
  1053 in typings (of consts etc.); internally the class is called
  1054 "HOL.type", ML programs should refer to HOLogic.typeS;
  1055 
  1056 * HOL/record package improvements:
  1057   - new derived operations "fields" to build a partial record section,
  1058     "extend" to promote a fixed record to a record scheme, and
  1059     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1060     declared as simp by default;
  1061   - shared operations ("more", "fields", etc.) now need to be always
  1062     qualified) --- potential INCOMPATIBILITY;
  1063   - removed "make_scheme" operations (use "make" with "extend") --
  1064     INCOMPATIBILITY;
  1065   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1066   - provides cases/induct rules for use with corresponding Isar
  1067     methods (for concrete records, record schemes, concrete more
  1068     parts, and schematic more parts -- in that order);
  1069   - internal definitions directly based on a light-weight abstract
  1070     theory of product types over typedef rather than datatype;
  1071 
  1072 * HOL: generic code generator for generating executable ML code from
  1073 specifications; specific support for HOL constructs such as inductive
  1074 datatypes and sets, as well as recursive functions; can be invoked
  1075 via 'generate_code' theory section;
  1076 
  1077 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1078 
  1079 * HOL: consolidated and renamed several theories.  In particular:
  1080         Ord.thy has been absorbed into HOL.thy
  1081         String.thy has been absorbed into List.thy
  1082 
  1083 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1084 (beware of argument permutation!);
  1085 
  1086 * HOL: linorder_less_split superseded by linorder_cases;
  1087 
  1088 * HOL/List: "nodups" renamed to "distinct";
  1089 
  1090 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1091 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1092   - Ex_def has changed, now need to use some_eq_ex
  1093 
  1094 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1095 in this (rare) case use:
  1096 
  1097   delSWrapper "split_all_tac"
  1098   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1099 
  1100 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1101 MAY FAIL;
  1102 
  1103 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1104 Isabelle's type classes, ^ on functions and relations has too general
  1105 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1106 necessary to attach explicit type constraints;
  1107 
  1108 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1109 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1110 renamed accordingly (eg "compI" -> "rel_compI").
  1111 
  1112 * HOL: syntax translations now work properly with numerals and records
  1113 expressions;
  1114 
  1115 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1116 of "lam" -- INCOMPATIBILITY;
  1117 
  1118 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1119 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1120 renamed "Product_Type.unit";
  1121 
  1122 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1123 
  1124 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1125 the "cases" method);
  1126 
  1127 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1128 Florian Kammller);
  1129 
  1130 * HOL/IMP: updated and converted to new-style theory format; several
  1131 parts turned into readable document, with proper Isar proof texts and
  1132 some explanations (by Gerwin Klein);
  1133 
  1134 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1135 
  1136 * HOL-Hyperreal is now a logic image;
  1137 
  1138 
  1139 *** HOLCF ***
  1140 
  1141 * Isar: consts/constdefs supports mixfix syntax for continuous
  1142 operations;
  1143 
  1144 * Isar: domain package adapted to new-style theory format, e.g. see
  1145 HOLCF/ex/Dnat.thy;
  1146 
  1147 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1148 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1149 lift.induct_tac, always use UU instead of Undef;
  1150 
  1151 * HOLCF/IMP: updated and converted to new-style theory;
  1152 
  1153 
  1154 *** ZF ***
  1155 
  1156 * Isar: proper integration of logic-specific tools and packages,
  1157 including theory commands '(co)inductive', '(co)datatype',
  1158 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1159 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1160 
  1161 * theory Main no longer includes AC; for the Axiom of Choice, base
  1162 your theory on Main_ZFC;
  1163 
  1164 * the integer library now covers quotients and remainders, with many
  1165 laws relating division to addition, multiplication, etc.;
  1166 
  1167 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1168 typeless version of the formalism;
  1169 
  1170 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1171 format;
  1172 
  1173 * ZF/Induct: new directory for examples of inductive definitions,
  1174 including theory Multiset for multiset orderings; converted to
  1175 new-style theory format;
  1176 
  1177 * ZF: many new theorems about lists, ordinals, etc.;
  1178 
  1179 
  1180 *** General ***
  1181 
  1182 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1183 variable proof controls level of detail: 0 = no proofs (only oracle
  1184 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1185 also ref manual for further ML interfaces;
  1186 
  1187 * Pure/axclass: removed obsolete ML interface
  1188 goal_subclass/goal_arity;
  1189 
  1190 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1191 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1192 separate tokens, so expressions involving minus need to be spaced
  1193 properly;
  1194 
  1195 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1196 rather than "infixl" or "infixr";
  1197 
  1198 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1199 sort constraint specifications in type inference; e.g. "x::_::foo"
  1200 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1201 type variable);
  1202 
  1203 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1204 control output of nested => (types); the default behavior is
  1205 "type_brackets";
  1206 
  1207 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1208 tokens into AST constants;
  1209 
  1210 * Pure/syntax: prefer later declarations of translations and print
  1211 translation functions; potential INCOMPATIBILITY: need to reverse
  1212 multiple declarations for same syntax element constant;
  1213 
  1214 * Pure/show_hyps reset by default (in accordance to existing Isar
  1215 practice);
  1216 
  1217 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1218 addSafter;
  1219 
  1220 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1221 as well;
  1222 
  1223 * system: tested support for MacOS X; should be able to get Isabelle +
  1224 Proof General to work in a plain Terminal after installing Poly/ML
  1225 (e.g. from the Isabelle distribution area) and GNU bash alone
  1226 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1227 support requires further installations, e.g. from
  1228 http://fink.sourceforge.net/);
  1229 
  1230 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1231 
  1232 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1233 of 40 MB), cf. ML_OPTIONS;
  1234 
  1235 * system: Proof General keywords specification is now part of the
  1236 Isabelle distribution (see etc/isar-keywords.el);
  1237 
  1238 * system: support for persistent Proof General sessions (refrain from
  1239 outdating all loaded theories on startup); user may create writable
  1240 logic images like this: ``isabelle -q HOL Test'';
  1241 
  1242 * system: smart selection of Isabelle process versus Isabelle
  1243 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1244 run both "isabelle" and "Isabelle" even if file names are badly
  1245 damaged (executable inspects the case of the first letter of its own
  1246 name); added separate "isabelle-process" and "isabelle-interface";
  1247 
  1248 * system: refrain from any attempt at filtering input streams; no
  1249 longer support ``8bit'' encoding of old isabelle font, instead proper
  1250 iso-latin characters may now be used; the related isatools
  1251 "symbolinput" and "nonascii" have disappeared as well;
  1252 
  1253 * system: removed old "xterm" interface (the print modes "xterm" and
  1254 "xterm_color" are still available for direct use in a suitable
  1255 terminal);
  1256 
  1257 
  1258 
  1259 New in Isabelle99-2 (February 2001)
  1260 -----------------------------------
  1261 
  1262 *** Overview of INCOMPATIBILITIES ***
  1263 
  1264 * HOL: please note that theories in the Library and elsewhere often use the
  1265 new-style (Isar) format; to refer to their theorems in an ML script you must
  1266 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1267 
  1268 * HOL: inductive package no longer splits induction rule aggressively,
  1269 but only as far as specified by the introductions given; the old
  1270 format may be recovered via ML function complete_split_rule or attribute
  1271 'split_rule (complete)';
  1272 
  1273 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1274 gfp_Tarski to gfp_unfold;
  1275 
  1276 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1277 
  1278 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1279 relation); infix "^^" has been renamed "``"; infix "``" has been
  1280 renamed "`"; "univalent" has been renamed "single_valued";
  1281 
  1282 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1283 operation;
  1284 
  1285 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1286 
  1287 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1288 
  1289 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1290 consequence, it is no longer monotonic wrt. the local goal context
  1291 (which is now passed through the inductive cases);
  1292 
  1293 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1294 \<gg> to \<ggreater>;
  1295 
  1296 
  1297 *** Document preparation ***
  1298 
  1299 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1300 available: are "it" for near math-mode best-style output, "sl" for
  1301 slanted text style, and "tt" for plain type-writer; if no
  1302 \isabellestyle command is given, output is according to slanted
  1303 type-writer);
  1304 
  1305 * support sub/super scripts (for single symbols only), input syntax is
  1306 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1307 
  1308 * some more standard symbols; see Appendix A of the system manual for
  1309 the complete list of symbols defined in isabellesym.sty;
  1310 
  1311 * improved isabelle style files; more abstract symbol implementation
  1312 (should now use \isamath{...} and \isatext{...} in custom symbol
  1313 definitions);
  1314 
  1315 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1316 state; Note that presentation of goal states does not conform to
  1317 actual human-readable proof documents.  Please do not include goal
  1318 states into document output unless you really know what you are doing!
  1319 
  1320 * proper indentation of antiquoted output with proportional LaTeX
  1321 fonts;
  1322 
  1323 * no_document ML operator temporarily disables LaTeX document
  1324 generation;
  1325 
  1326 * isatool unsymbolize tunes sources for plain ASCII communication;
  1327 
  1328 
  1329 *** Isar ***
  1330 
  1331 * Pure: Isar now suffers initial goal statements to contain unbound
  1332 schematic variables (this does not conform to actual readable proof
  1333 documents, due to unpredictable outcome and non-compositional proof
  1334 checking); users who know what they are doing may use schematic goals
  1335 for Prolog-style synthesis of proven results;
  1336 
  1337 * Pure: assumption method (an implicit finishing) now handles actual
  1338 rules as well;
  1339 
  1340 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1341 initial goal, declare "that" only as Pure intro (only for single
  1342 steps); the "that" rule assumption may now be involved in implicit
  1343 finishing, thus ".." becomes a feasible for trivial obtains;
  1344 
  1345 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1346 instance proofs may be performed by "..";
  1347 
  1348 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1349 statements as well;
  1350 
  1351 * Pure: more robust selection of calculational rules;
  1352 
  1353 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1354 rule (as well as the assumption rule);
  1355 
  1356 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1357 lemmas, using the graph browser tool;
  1358 
  1359 * Pure: predict failure of "show" in interactive mode;
  1360 
  1361 * Pure: 'thms_containing' now takes actual terms as arguments;
  1362 
  1363 * HOL: improved method 'induct' --- now handles non-atomic goals
  1364 (potential INCOMPATIBILITY); tuned error handling;
  1365 
  1366 * HOL: cases and induct rules now provide explicit hints about the
  1367 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1368 any remaining facts are inserted into the goal verbatim;
  1369 
  1370 * HOL: local contexts (aka cases) may now contain term bindings as
  1371 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1372 the result to be shown in each case;
  1373 
  1374 * HOL: added 'recdef_tc' command;
  1375 
  1376 * isatool convert assists in eliminating legacy ML scripts;
  1377 
  1378 
  1379 *** HOL ***
  1380 
  1381 * HOL/Library: a collection of generic theories to be used together
  1382 with main HOL; the theory loader path already includes this directory
  1383 by default; the following existing theories have been moved here:
  1384 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1385 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1386 
  1387 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1388 modelling and verification task performed in Isabelle/HOL +
  1389 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1390 
  1391 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1392 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1393 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1394 'domain', this makes the theory consistent with mathematical
  1395 literature;
  1396 
  1397 * HOL basics: added overloaded operations "inverse" and "divide"
  1398 (infix "/"), syntax for generic "abs" operation, generic summation
  1399 operator \<Sum>;
  1400 
  1401 * HOL/typedef: simplified package, provide more useful rules (see also
  1402 HOL/subset.thy);
  1403 
  1404 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1405 now expressed as a proper nested rule (old-style tactic scripts may
  1406 require atomize_strip_tac to cope with non-atomic premises);
  1407 
  1408 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1409 to "split_conv" (old name still available for compatibility);
  1410 
  1411 * HOL: improved concrete syntax for strings (e.g. allows translation
  1412 rules with string literals);
  1413 
  1414 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1415  and Fleuriot's mechanization of analysis, including the transcendental
  1416  functions for the reals;
  1417 
  1418 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1419 
  1420 
  1421 *** CTT ***
  1422 
  1423 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1424 "lam" is displayed as TWO lambda-symbols
  1425 
  1426 * CTT: theory Main now available, containing everything (that is, Bool
  1427 and Arith);
  1428 
  1429 
  1430 *** General ***
  1431 
  1432 * Pure: the Simplifier has been implemented properly as a derived rule
  1433 outside of the actual kernel (at last!); the overall performance
  1434 penalty in practical applications is about 50%, while reliability of
  1435 the Isabelle inference kernel has been greatly improved;
  1436 
  1437 * print modes "brackets" and "no_brackets" control output of nested =>
  1438 (types) and ==> (props); the default behaviour is "brackets";
  1439 
  1440 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1441 as assumptions as well;
  1442 
  1443 * system: support Poly/ML 4.0;
  1444 
  1445 * system: isatool install handles KDE version 1 or 2;
  1446 
  1447 
  1448 
  1449 New in Isabelle99-1 (October 2000)
  1450 ----------------------------------
  1451 
  1452 *** Overview of INCOMPATIBILITIES ***
  1453 
  1454 * HOL: simplification of natural numbers is much changed; to partly
  1455 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1456 issue the following ML commands:
  1457 
  1458   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1459   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1460 
  1461 * HOL: simplification no longer dives into case-expressions; this is
  1462 controlled by "t.weak_case_cong" for each datatype t;
  1463 
  1464 * HOL: nat_less_induct renamed to less_induct;
  1465 
  1466 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1467 fixsome to patch .thy and .ML sources automatically;
  1468 
  1469   select_equality  -> some_equality
  1470   select_eq_Ex     -> some_eq_ex
  1471   selectI2EX       -> someI2_ex
  1472   selectI2         -> someI2
  1473   selectI          -> someI
  1474   select1_equality -> some1_equality
  1475   Eps_sym_eq       -> some_sym_eq_trivial
  1476   Eps_eq           -> some_eq_trivial
  1477 
  1478 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1479 
  1480 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1481 instead);
  1482 
  1483 * HOL: the recursion equations generated by 'recdef' are now called
  1484 f.simps instead of f.rules;
  1485 
  1486 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1487 
  1488 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1489 sometimes be needed;
  1490 
  1491 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1492 
  1493 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1494 
  1495 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1496 product is now "<*>" instead of "Times"; the lexicographic product is
  1497 now "<*lex*>" instead of "**";
  1498 
  1499 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1500 of main HOL, but was unused); better use HOL's datatype package;
  1501 
  1502 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1503 the old syntax may be recovered as follows:
  1504 
  1505   syntax (symbols)
  1506     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1507       (infixl "\\<oplus>" 100)
  1508 
  1509 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1510 
  1511 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1512 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1513 internally;
  1514 
  1515 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1516 changed from A/r to A//r;
  1517 
  1518 * ZF: new treatment of arithmetic (nat & int) may break some old
  1519 proofs;
  1520 
  1521 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1522 rulify -> rule_format, elimify -> elim_format, ...);
  1523 
  1524 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1525 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1526 should have to change intro!! to intro? only); replaced "delrule" by
  1527 "rule del";
  1528 
  1529 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1530 
  1531 * Provers: strengthened force_tac by using new first_best_tac;
  1532 
  1533 * LaTeX document preparation: several changes of isabelle.sty (see
  1534 lib/texinputs);
  1535 
  1536 
  1537 *** Document preparation ***
  1538 
  1539 * formal comments (text blocks etc.) in new-style theories may now
  1540 contain antiquotations of thm/prop/term/typ/text to be presented
  1541 according to latex print mode; concrete syntax is like this:
  1542 @{term[show_types] "f(x) = a + x"};
  1543 
  1544 * isatool mkdir provides easy setup of Isabelle session directories,
  1545 including proper document sources;
  1546 
  1547 * generated LaTeX sources are now deleted after successful run
  1548 (isatool document -c); may retain a copy somewhere else via -D option
  1549 of isatool usedir;
  1550 
  1551 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1552 style files, achieving self-contained LaTeX sources and simplifying
  1553 LaTeX debugging;
  1554 
  1555 * old-style theories now produce (crude) LaTeX output as well;
  1556 
  1557 * browser info session directories are now self-contained (may be put
  1558 on WWW server seperately); improved graphs of nested sessions; removed
  1559 graph for 'all sessions';
  1560 
  1561 * several improvements in isabelle style files; \isabellestyle{it}
  1562 produces fake math mode output; \isamarkupheader is now \section by
  1563 default; see lib/texinputs/isabelle.sty etc.;
  1564 
  1565 
  1566 *** Isar ***
  1567 
  1568 * Isar/Pure: local results and corresponding term bindings are now
  1569 subject to Hindley-Milner polymorphism (similar to ML); this
  1570 accommodates incremental type-inference very nicely;
  1571 
  1572 * Isar/Pure: new derived language element 'obtain' supports
  1573 generalized existence reasoning;
  1574 
  1575 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1576 support accumulation of results, without applying any rules yet;
  1577 useful to collect intermediate results without explicit name
  1578 references, and for use with transitivity rules with more than 2
  1579 premises;
  1580 
  1581 * Isar/Pure: scalable support for case-analysis type proofs: new
  1582 'case' language element refers to local contexts symbolically, as
  1583 produced by certain proof methods; internally, case names are attached
  1584 to theorems as "tags";
  1585 
  1586 * Isar/Pure: theory command 'hide' removes declarations from
  1587 class/type/const name spaces;
  1588 
  1589 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1590 indicate potential overloading;
  1591 
  1592 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1593 
  1594 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1595 "{a,b,c}" instead of {a,b,c};
  1596 
  1597 * Isar/Pure now provides its own version of intro/elim/dest
  1598 attributes; useful for building new logics, but beware of confusion
  1599 with the version in Provers/classical;
  1600 
  1601 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1602 case name 'antecedent';
  1603 
  1604 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1605 to the current context is now done automatically);
  1606 
  1607 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1608 for definining proof methods in ML;
  1609 
  1610 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1611 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1612 most cases, one should have to change intro!! to intro? only);
  1613 replaced "delrule" by "rule del";
  1614 
  1615 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1616 'symmetric' attribute (the latter supercedes [RS sym]);
  1617 
  1618 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1619 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1620 well (including splits);
  1621 
  1622 * Isar/Provers: Simplifier and Classical methods now support all kind
  1623 of modifiers used in the past, including 'cong', 'iff', etc.
  1624 
  1625 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1626 of Simplifier and Classical reasoner);
  1627 
  1628 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1629 now support named cases; major packages (inductive, datatype, primrec,
  1630 recdef) support case names and properly name parameters;
  1631 
  1632 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1633 monotonicity conditions are extracted to be proven at end of
  1634 calculations;
  1635 
  1636 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1637 method anyway;
  1638 
  1639 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1640 split_if split_if_asm; datatype package provides theorems foo.splits =
  1641 foo.split foo.split_asm for each datatype;
  1642 
  1643 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1644 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1645 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1646 use "(cases (simplified))" method in proper proof texts);
  1647 
  1648 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1649 
  1650 * Isar: names of theorems etc. may be natural numbers as well;
  1651 
  1652 * Isar: 'pr' command: optional arguments for goals_limit and
  1653 ProofContext.prems_limit; no longer prints theory contexts, but only
  1654 proof states;
  1655 
  1656 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1657 additional print modes to be specified; e.g. "pr(latex)" will print
  1658 proof state according to the Isabelle LaTeX style;
  1659 
  1660 * Isar: improved support for emulating tactic scripts, including proof
  1661 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1662 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1663 (for HOL datatypes);
  1664 
  1665 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1666 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1667 'proof method scripts' have to be in depth-first order;
  1668 
  1669 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1670 
  1671 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1672 should instead use individual commands for printing items
  1673 (print_commands, print_methods etc.);
  1674 
  1675 * Isar: added 'nothing' --- the empty list of theorems;
  1676 
  1677 
  1678 *** HOL ***
  1679 
  1680 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1681 corresponding virtual machine and a specification of its bytecode
  1682 verifier and a lightweight bytecode verifier, including proofs of
  1683 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1684 Cornelia Pusch (see also the homepage of project Bali at
  1685 http://isabelle.in.tum.de/Bali/);
  1686 
  1687 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1688 Clemens Ballarin;
  1689 
  1690 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1691 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1692 Rasmussen;
  1693 
  1694 * HOL/Lattice: fundamental concepts of lattice theory and order
  1695 structures, including duals, properties of bounds versus algebraic
  1696 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1697 Theorem for complete lattices etc.; may also serve as a demonstration
  1698 for abstract algebraic reasoning using axiomatic type classes, and
  1699 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1700 
  1701 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1702 von Oheimb;
  1703 
  1704 * HOL/IMPP: extension of IMP with local variables and mutually
  1705 recursive procedures, by David von Oheimb;
  1706 
  1707 * HOL/Lambda: converted into new-style theory and document;
  1708 
  1709 * HOL/ex/Multiquote: example of multiple nested quotations and
  1710 anti-quotations -- basically a generalized version of de-Bruijn
  1711 representation; very useful in avoiding lifting of operations;
  1712 
  1713 * HOL/record: added general record equality rule to simpset; fixed
  1714 select-update simplification procedure to handle extended records as
  1715 well; admit "r" as field name;
  1716 
  1717 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1718 other numeric types and also as the identity of groups, rings, etc.;
  1719 
  1720 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1721 Types nat and int belong to this axclass;
  1722 
  1723 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1724    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1725    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1726   two terms #m*u and #n*u are replaced by #(m+n)*u
  1727     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1728   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1729     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1730 
  1731 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1732 powerful prover for predicate logic but knows nothing of clasets; see
  1733 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1734 
  1735 * HOL: new version of "case_tac" subsumes both boolean case split and
  1736 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1737 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1738 
  1739 * HOL: simplification no longer dives into case-expressions: only the
  1740 selector expression is simplified, but not the remaining arms; to
  1741 enable full simplification of case-expressions for datatype t, you may
  1742 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1743 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1744 
  1745 * HOL/recdef: the recursion equations generated by 'recdef' for
  1746 function 'f' are now called f.simps instead of f.rules; if all
  1747 termination conditions are proved automatically, these simplification
  1748 rules are added to the simpset, as in primrec; rules may be named
  1749 individually as well, resulting in a separate list of theorems for
  1750 each equation;
  1751 
  1752 * HOL/While is a new theory that provides a while-combinator. It
  1753 permits the definition of tail-recursive functions without the
  1754 provision of a termination measure. The latter is necessary once the
  1755 invariant proof rule for while is applied.
  1756 
  1757 * HOL: new (overloaded) notation for the set of elements below/above
  1758 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1759 
  1760 * HOL: theorems impI, allI, ballI bound as "strip";
  1761 
  1762 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1763 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1764 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1765 
  1766 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1767 
  1768 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1769 main HOL, but was unused);
  1770 
  1771 * HOL: fewer consts declared as global (e.g. have to refer to
  1772 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1773 
  1774 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1775 in case of overlap with user translations (e.g. judgements over
  1776 tuples); (note that the underlying logical represenation is still
  1777 bogus);
  1778 
  1779 
  1780 *** ZF ***
  1781 
  1782 * ZF: simplification automatically cancels common terms in arithmetic
  1783 expressions over nat and int;
  1784 
  1785 * ZF: new treatment of nat to minimize type-checking: all operators
  1786 coerce their operands to a natural number using the function natify,
  1787 making the algebraic laws unconditional;
  1788 
  1789 * ZF: as above, for int: operators coerce their operands to an integer
  1790 using the function intify;
  1791 
  1792 * ZF: the integer library now contains many of the usual laws for the
  1793 orderings, including $<=, and monotonicity laws for $+ and $*;
  1794 
  1795 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1796 simplification;
  1797 
  1798 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1799 to the simplifier and classical reasoner simultaneously;
  1800 
  1801 
  1802 *** General ***
  1803 
  1804 * Provers: blast_tac now handles actual object-logic rules as
  1805 assumptions; note that auto_tac uses blast_tac internally as well;
  1806 
  1807 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1808 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1809 
  1810 * Provers: delrules now handles destruct rules as well (no longer need
  1811 explicit make_elim);
  1812 
  1813 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1814   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1815 use instead the strong form,
  1816   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1817 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1818 from destruct-rules;
  1819 
  1820 * Provers: Simplifier.easy_setup provides a fast path to basic
  1821 Simplifier setup for new object-logics;
  1822 
  1823 * Pure: AST translation rules no longer require constant head on LHS;
  1824 
  1825 * Pure: improved name spaces: ambiguous output is qualified; support
  1826 for hiding of names;
  1827 
  1828 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1829 XSYMBOL_HOME; no longer need to do manual configuration in most
  1830 situations;
  1831 
  1832 * system: compression of ML heaps images may now be controlled via -c
  1833 option of isabelle and isatool usedir (currently only observed by
  1834 Poly/ML);
  1835 
  1836 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1837 useful for remote X11);
  1838 
  1839 * system: provide TAGS file for Isabelle sources;
  1840 
  1841 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1842 order;
  1843 
  1844 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1845 timing flag supersedes proof_timing and Toplevel.trace;
  1846 
  1847 * ML: new combinators |>> and |>>> for incremental transformations
  1848 with secondary results (e.g. certain theory extensions):
  1849 
  1850 * ML: PureThy.add_defs gets additional argument to indicate potential
  1851 overloading (usually false);
  1852 
  1853 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1854 results;
  1855 
  1856 
  1857 
  1858 New in Isabelle99 (October 1999)
  1859 --------------------------------
  1860 
  1861 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1862 
  1863 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1864 are no longer simplified.  (This allows the simplifier to unfold recursive
  1865 functional programs.)  To restore the old behaviour, declare
  1866 
  1867     Delcongs [if_weak_cong];
  1868 
  1869 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1870 complement;
  1871 
  1872 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1873 
  1874 * HOL/datatype: mutual_induct_tac no longer exists --
  1875   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1876 
  1877 * HOL/typedef: fixed type inference for representing set; type
  1878 arguments now have to occur explicitly on the rhs as type constraints;
  1879 
  1880 * ZF: The con_defs part of an inductive definition may no longer refer
  1881 to constants declared in the same theory;
  1882 
  1883 * HOL, ZF: the function mk_cases, generated by the inductive
  1884 definition package, has lost an argument.  To simplify its result, it
  1885 uses the default simpset instead of a supplied list of theorems.
  1886 
  1887 * HOL/List: the constructors of type list are now Nil and Cons;
  1888 
  1889 * Simplifier: the type of the infix ML functions
  1890         setSSolver addSSolver setSolver addSolver
  1891 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1892 for packaging solvers. A solver is created via
  1893         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1894 where the string argument is only a comment.
  1895 
  1896 
  1897 *** Proof tools ***
  1898 
  1899 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1900 decision procedure for linear arithmetic. Currently it is used for
  1901 types `nat', `int', and `real' in HOL (see below); it can, should and
  1902 will be instantiated for other types and logics as well.
  1903 
  1904 * The simplifier now accepts rewrite rules with flexible heads, eg
  1905      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1906   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1907   matching.
  1908 
  1909 
  1910 *** General ***
  1911 
  1912 * New Isabelle/Isar subsystem provides an alternative to traditional
  1913 tactical theorem proving; together with the ProofGeneral/isar user
  1914 interface it offers an interactive environment for developing human
  1915 readable proof documents (Isar == Intelligible semi-automated
  1916 reasoning); for further information see isatool doc isar-ref,
  1917 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1918 
  1919 * improved and simplified presentation of theories: better HTML markup
  1920 (including colors), graph views in several sizes; isatool usedir now
  1921 provides a proper interface for user theories (via -P option); actual
  1922 document preparation based on (PDF)LaTeX is available as well (for
  1923 new-style theories only); see isatool doc system for more information;
  1924 
  1925 * native support for Proof General, both for classic Isabelle and
  1926 Isabelle/Isar;
  1927 
  1928 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1929 using the graph browser tool;
  1930 
  1931 * Isabelle manuals now also available as PDF;
  1932 
  1933 * theory loader rewritten from scratch (may not be fully
  1934 bug-compatible); old loadpath variable has been replaced by show_path,
  1935 add_path, del_path, reset_path functions; new operations such as
  1936 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1937 isatool doc ref);
  1938 
  1939 * improved isatool install: option -k creates KDE application icon,
  1940 option -p DIR installs standalone binaries;
  1941 
  1942 * added ML_PLATFORM setting (useful for cross-platform installations);
  1943 more robust handling of platform specific ML images for SML/NJ;
  1944 
  1945 * the settings environment is now statically scoped, i.e. it is never
  1946 created again in sub-processes invoked from isabelle, isatool, or
  1947 Isabelle;
  1948 
  1949 * path element specification '~~' refers to '$ISABELLE_HOME';
  1950 
  1951 * in locales, the "assumes" and "defines" parts may be omitted if
  1952 empty;
  1953 
  1954 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1955 long arrows);
  1956 
  1957 * new print_mode "HTML";
  1958 
  1959 * new flag show_tags controls display of tags of theorems (which are
  1960 basically just comments that may be attached by some tools);
  1961 
  1962 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1963 mode and goal output format:
  1964 
  1965 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1966 244c244
  1967 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1968 ---
  1969 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1970 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1971 181c181
  1972 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1973 ---
  1974 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1975 
  1976 * function bind_thms stores lists of theorems (cf. bind_thm);
  1977 
  1978 * new shorthand tactics ftac, eatac, datac, fatac;
  1979 
  1980 * qed (and friends) now accept "" as result name; in that case the
  1981 theorem is not stored, but proper checks and presentation of the
  1982 result still apply;
  1983 
  1984 * theorem database now also indexes constants "Trueprop", "all",
  1985 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1986 
  1987 
  1988 *** HOL ***
  1989 
  1990 ** HOL arithmetic **
  1991 
  1992 * There are now decision procedures for linear arithmetic over nat and
  1993 int:
  1994 
  1995 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1996 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1997 are treated as atomic; subformulae not involving type `nat' or `int'
  1998 are ignored; quantified subformulae are ignored unless they are
  1999 positive universal or negative existential. The tactic has to be
  2000 invoked by hand and can be a little bit slow. In particular, the
  2001 running time is exponential in the number of occurrences of `min' and
  2002 `max', and `-' on `nat'.
  2003 
  2004 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2005 (negated) (in)equalities among the premises and the conclusion into
  2006 account (i.e. no compound formulae) and does not know about `min' and
  2007 `max', and `-' on `nat'. It is fast and is used automatically by the
  2008 simplifier.
  2009 
  2010 NB: At the moment, these decision procedures do not cope with mixed
  2011 nat/int formulae where the two parts interact, such as `m < n ==>
  2012 int(m) < int(n)'.
  2013 
  2014 * HOL/Numeral provides a generic theory of numerals (encoded
  2015 efficiently as bit strings); setup for types nat/int/real is in place;
  2016 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2017 int, existing theories and proof scripts may require a few additional
  2018 type constraints;
  2019 
  2020 * integer division and remainder can now be performed on constant
  2021 arguments;
  2022 
  2023 * many properties of integer multiplication, division and remainder
  2024 are now available;
  2025 
  2026 * An interface to the Stanford Validity Checker (SVC) is available through the
  2027 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2028 are proved automatically.  SVC must be installed separately, and its results
  2029 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2030 invocation of the underlying oracle).  For SVC see
  2031   http://verify.stanford.edu/SVC
  2032 
  2033 * IsaMakefile: the HOL-Real target now builds an actual image;
  2034 
  2035 
  2036 ** HOL misc **
  2037 
  2038 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2039 (in Isabelle/Isar) -- by Gertrud Bauer;
  2040 
  2041 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2042 analysis for assembly languages with subtypes;
  2043 
  2044 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2045 -- avoids syntactic ambiguities and treats state, transition, and
  2046 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2047 changed syntax and (many) tactics;
  2048 
  2049 * HOL/inductive: Now also handles more general introduction rules such
  2050   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2051   theorems are now maintained within the theory (maintained via the
  2052   "mono" attribute);
  2053 
  2054 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2055   (using function types) such as
  2056 
  2057   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2058 
  2059 * HOL/record: record_simproc (part of the default simpset) takes care
  2060 of selectors applied to updated records; record_split_tac is no longer
  2061 part of the default claset; update_defs may now be removed from the
  2062 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2063 
  2064   claset_ref () := claset() addSWrapper record_split_wrapper;
  2065   Delsimprocs [record_simproc]
  2066 
  2067 * HOL/typedef: fixed type inference for representing set; type
  2068 arguments now have to occur explicitly on the rhs as type constraints;
  2069 
  2070 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2071 names rather than an ML expression;
  2072 
  2073 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2074 supplied later.  Program schemes can be defined, such as
  2075     "While B C s = (if B s then While B C (C s) else s)"
  2076 where the well-founded relation can be chosen after B and C have been given.
  2077 
  2078 * HOL/List: the constructors of type list are now Nil and Cons;
  2079 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2080 course, ML tools referring to List.list.op # etc. have to be adapted;
  2081 
  2082 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2083 disabled by default; run isabelle with option -m HOL to get back to
  2084 the original Gordon/HOL-style output;
  2085 
  2086 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2087 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2088 
  2089 * HOL basic syntax simplified (more orthogonal): all variants of
  2090 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2091 Eps operator is provided as well: "SOME x. P[x]";
  2092 
  2093 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2094 
  2095 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2096 thus available for user theories;
  2097 
  2098 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2099 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2100 time;
  2101 
  2102 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2103 several times and then mp;
  2104 
  2105 
  2106 *** LK ***
  2107 
  2108 * the notation <<...>> is now available as a notation for sequences of
  2109 formulas;
  2110 
  2111 * the simplifier is now installed
  2112 
  2113 * the axiom system has been generalized (thanks to Soren Heilmann)
  2114 
  2115 * the classical reasoner now has a default rule database
  2116 
  2117 
  2118 *** ZF ***
  2119 
  2120 * new primrec section allows primitive recursive functions to be given
  2121 directly (as in HOL) over datatypes and the natural numbers;
  2122 
  2123 * new tactics induct_tac and exhaust_tac for induction (or case
  2124 analysis) over datatypes and the natural numbers;
  2125 
  2126 * the datatype declaration of type T now defines the recursor T_rec;
  2127 
  2128 * simplification automatically does freeness reasoning for datatype
  2129 constructors;
  2130 
  2131 * automatic type-inference, with AddTCs command to insert new
  2132 type-checking rules;
  2133 
  2134 * datatype introduction rules are now added as Safe Introduction rules
  2135 to the claset;
  2136 
  2137 * the syntax "if P then x else y" is now available in addition to
  2138 if(P,x,y);
  2139 
  2140 
  2141 *** Internal programming interfaces ***
  2142 
  2143 * tuned simplifier trace output; new flag debug_simp;
  2144 
  2145 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2146 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2147 
  2148 * AxClass.axclass_tac lost the theory argument;
  2149 
  2150 * tuned current_goals_markers semantics: begin / end goal avoids
  2151 printing empty lines;
  2152 
  2153 * removed prs and prs_fn hook, which was broken because it did not
  2154 include \n in its semantics, forcing writeln to add one
  2155 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2156 string -> unit if you really want to output text without newline;
  2157 
  2158 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2159 plain output, interface builders may have to enable 'isabelle_font'
  2160 mode to get Isabelle font glyphs as before;
  2161 
  2162 * refined token_translation interface; INCOMPATIBILITY: output length
  2163 now of type real instead of int;
  2164 
  2165 * theory loader actions may be traced via new ThyInfo.add_hook
  2166 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2167 your own database of information attached to *whole* theories -- as
  2168 opposed to intra-theory data slots offered via TheoryDataFun;
  2169 
  2170 * proper handling of dangling sort hypotheses (at last!);
  2171 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2172 extra sort hypotheses that can be witnessed from the type signature;
  2173 the force_strip_shyps flag is gone, any remaining shyps are simply
  2174 left in the theorem (with a warning issued by strip_shyps_warning);
  2175 
  2176 
  2177 
  2178 New in Isabelle98-1 (October 1998)
  2179 ----------------------------------
  2180 
  2181 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2182 
  2183 * several changes of automated proof tools;
  2184 
  2185 * HOL: major changes to the inductive and datatype packages, including
  2186 some minor incompatibilities of theory syntax;
  2187 
  2188 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2189 called `inj_on';
  2190 
  2191 * HOL: removed duplicate thms in Arith:
  2192   less_imp_add_less  should be replaced by  trans_less_add1
  2193   le_imp_add_le      should be replaced by  trans_le_add1
  2194 
  2195 * HOL: unary minus is now overloaded (new type constraints may be
  2196 required);
  2197 
  2198 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2199 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2200 now taken as an integer constant.
  2201 
  2202 * Pure: ML function 'theory_of' renamed to 'theory';
  2203 
  2204 
  2205 *** Proof tools ***
  2206 
  2207 * Simplifier:
  2208   1. Asm_full_simp_tac is now more aggressive.
  2209      1. It will sometimes reorient premises if that increases their power to
  2210         simplify.
  2211      2. It does no longer proceed strictly from left to right but may also
  2212         rotate premises to achieve further simplification.
  2213      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2214      old Asm_full_simp_tac in that it does not rotate premises.
  2215   2. The simplifier now knows a little bit about nat-arithmetic.
  2216 
  2217 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2218 allows for selected deletion of wrappers, by introduction of names for
  2219 wrapper functionals.  This implies that addbefore, addSbefore,
  2220 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2221 and that adding two tactics with the same name overwrites the first
  2222 one (emitting a warning).
  2223   type wrapper = (int -> tactic) -> (int -> tactic)
  2224   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2225   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2226   delWrapper, delSWrapper: claset *  string            -> claset
  2227   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2228 
  2229 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2230 semantics; addbefore now affects only the unsafe part of step_tac
  2231 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2232 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2233 by Force_tac;
  2234 
  2235 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2236 compWrapper; added safe wrapper (and access functions for it);
  2237 
  2238 * HOL/split_all_tac is now much faster and fails if there is nothing
  2239 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2240 and the names of the automatically generated variables have changed.
  2241 split_all_tac has moved within claset() from unsafe wrappers to safe
  2242 wrappers, which means that !!-bound variables are split much more
  2243 aggressively, and safe_tac and clarify_tac now split such variables.
  2244 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2245 Note: the same holds for record_split_tac, which does the job of
  2246 split_all_tac for record fields.
  2247 
  2248 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2249 permanently to the default simpset using Addsplits just like
  2250 Addsimps. They can be removed via Delsplits just like
  2251 Delsimps. Lower-case versions are also available.
  2252 
  2253 * HOL/Simplifier: The rule split_if is now part of the default
  2254 simpset. This means that the simplifier will eliminate all occurrences
  2255 of if-then-else in the conclusion of a goal. To prevent this, you can
  2256 either remove split_if completely from the default simpset by
  2257 `Delsplits [split_if]' or remove it in a specific call of the
  2258 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2259 other case splitting rules to/from the default simpset: every datatype
  2260 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2261 t is the name of the datatype).
  2262 
  2263 * Classical reasoner / Simplifier combination: new force_tac (and
  2264 derivatives Force_tac, force) combines rewriting and classical
  2265 reasoning (and whatever other tools) similarly to auto_tac, but is
  2266 aimed to solve the given subgoal completely.
  2267 
  2268 
  2269 *** General ***
  2270 
  2271 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2272 and `goalw': the theory is no longer needed as an explicit argument -
  2273 the current theory context is used; assumptions are no longer returned
  2274 at the ML-level unless one of them starts with ==> or !!; it is
  2275 recommended to convert to these new commands using isatool fixgoal
  2276 (backup your sources first!);
  2277 
  2278 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2279 the current theory context, and 'theory' to lookup stored theories;
  2280 
  2281 * new theory section 'locale' for declaring constants, assumptions and
  2282 definitions that have local scope;
  2283 
  2284 * new theory section 'nonterminals' for purely syntactic types;
  2285 
  2286 * new theory section 'setup' for generic ML setup functions
  2287 (e.g. package initialization);
  2288 
  2289 * the distribution now includes Isabelle icons: see
  2290 lib/logo/isabelle-{small,tiny}.xpm;
  2291 
  2292 * isatool install - install binaries with absolute references to
  2293 ISABELLE_HOME/bin;
  2294 
  2295 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2296 
  2297 * print mode 'emacs' reserved for Isamode;
  2298 
  2299 * support multiple print (ast) translations per constant name;
  2300 
  2301 * theorems involving oracles are now printed with a suffixed [!];
  2302 
  2303 
  2304 *** HOL ***
  2305 
  2306 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2307 
  2308 * HOL/inductive package reorganized and improved: now supports mutual
  2309 definitions such as
  2310 
  2311   inductive EVEN ODD
  2312     intrs
  2313       null "0 : EVEN"
  2314       oddI "n : EVEN ==> Suc n : ODD"
  2315       evenI "n : ODD ==> Suc n : EVEN"
  2316 
  2317 new theorem list "elims" contains an elimination rule for each of the
  2318 recursive sets; inductive definitions now handle disjunctive premises
  2319 correctly (also ZF);
  2320 
  2321 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2322 "mutual_induct" no longer exists - the induction rule is always
  2323 contained in "induct";
  2324 
  2325 
  2326 * HOL/datatype package re-implemented and greatly improved: now
  2327 supports mutually recursive datatypes such as
  2328 
  2329   datatype
  2330     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2331             | SUM ('a aexp) ('a aexp)
  2332             | DIFF ('a aexp) ('a aexp)
  2333             | NUM 'a
  2334   and
  2335     'a bexp = LESS ('a aexp) ('a aexp)
  2336             | AND ('a bexp) ('a bexp)
  2337             | OR ('a bexp) ('a bexp)
  2338 
  2339 as well as indirectly recursive datatypes such as
  2340 
  2341   datatype
  2342     ('a, 'b) term = Var 'a
  2343                   | App 'b ((('a, 'b) term) list)
  2344 
  2345 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2346 induction on mutually / indirectly recursive datatypes.
  2347 
  2348 Primrec equations are now stored in theory and can be accessed via
  2349 <function_name>.simps.
  2350 
  2351 INCOMPATIBILITIES:
  2352 
  2353   - Theories using datatypes must now have theory Datatype as an
  2354     ancestor.
  2355   - The specific <typename>.induct_tac no longer exists - use the
  2356     generic induct_tac instead.
  2357   - natE has been renamed to nat.exhaust - use exhaust_tac
  2358     instead of res_inst_tac ... natE. Note that the variable
  2359     names in nat.exhaust differ from the names in natE, this
  2360     may cause some "fragile" proofs to fail.
  2361   - The theorems split_<typename>_case and split_<typename>_case_asm
  2362     have been renamed to <typename>.split and <typename>.split_asm.
  2363   - Since default sorts of type variables are now handled correctly,
  2364     some datatype definitions may have to be annotated with explicit
  2365     sort constraints.
  2366   - Primrec definitions no longer require function name and type
  2367     of recursive argument.
  2368 
  2369 Consider using isatool fixdatatype to adapt your theories and proof
  2370 scripts to the new package (backup your sources first!).
  2371 
  2372 
  2373 * HOL/record package: considerably improved implementation; now
  2374 includes concrete syntax for record types, terms, updates; theorems
  2375 for surjective pairing and splitting !!-bound record variables; proof
  2376 support is as follows:
  2377 
  2378   1) standard conversions (selectors or updates applied to record
  2379 constructor terms) are part of the standard simpset;
  2380 
  2381   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2382 made part of standard simpset and claset via addIffs;
  2383 
  2384   3) a tactic for record field splitting (record_split_tac) is part of
  2385 the standard claset (addSWrapper);
  2386 
  2387 To get a better idea about these rules you may retrieve them via
  2388 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2389 the name of your record type.
  2390 
  2391 The split tactic 3) conceptually simplifies by the following rule:
  2392 
  2393   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2394 
  2395 Thus any record variable that is bound by meta-all will automatically
  2396 blow up into some record constructor term, consequently the
  2397 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2398 solve record problems automatically.
  2399 
  2400 
  2401 * reorganized the main HOL image: HOL/Integ and String loaded by
  2402 default; theory Main includes everything;
  2403 
  2404 * automatic simplification of integer sums and comparisons, using cancellation;
  2405 
  2406 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2407 
  2408 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2409 
  2410 * many new identities for unions, intersections, set difference, etc.;
  2411 
  2412 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2413 called split_if, split_split, split_sum_case and split_nat_case (to go
  2414 with add/delsplits);
  2415 
  2416 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2417 (?x::unit) = (); this is made part of the default simpset, which COULD
  2418 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2419 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2420 unit_abs_eta_conv is added in order to counter the effect of
  2421 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2422 %u.f();
  2423 
  2424 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2425 makes more sense);
  2426 
  2427 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2428   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2429   disjointness reasoning but breaking a few old proofs.
  2430 
  2431 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2432 to 'converse' from 'inverse' (for compatibility with ZF and some
  2433 literature);
  2434 
  2435 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2436 the well-founded relation;
  2437 
  2438 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2439     Compl A.  The "Compl" syntax remains available as input syntax for this
  2440     release ONLY.
  2441 
  2442 * HOL/Update: new theory of function updates:
  2443     f(a:=b) == %x. if x=a then b else f x
  2444 may also be iterated as in f(a:=b,c:=d,...);
  2445 
  2446 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2447 
  2448 * HOL/List:
  2449   - new function list_update written xs[i:=v] that updates the i-th
  2450     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2451   - new function `upt' written [i..j(] which generates the list
  2452     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2453     bound write [i..j], which is a shorthand for [i..j+1(].
  2454   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2455 
  2456 * HOL/Arith:
  2457   - removed 'pred' (predecessor) function;
  2458   - generalized some theorems about n-1;
  2459   - many new laws about "div" and "mod";
  2460   - new laws about greatest common divisors (see theory ex/Primes);
  2461 
  2462 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2463 instead of "inverse";
  2464 
  2465 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2466   of the multiset ordering;
  2467 
  2468 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2469   (not included by default);
  2470 
  2471 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2472 
  2473 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2474   programs, i.e. different program variables may have different types.
  2475 
  2476 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2477   [previously, this check worked only if the rewrite rule was unconditional]
  2478   Now rew can involve either definitions or equalities (either == or =).
  2479 
  2480 
  2481 *** ZF ***
  2482 
  2483 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2484   only the theorems proved on ZF.ML;
  2485 
  2486 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2487   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2488   disjointness reasoning but breaking a few old proofs.
  2489 
  2490 * ZF/Update: new theory of function updates
  2491     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2492   may also be iterated as in f(a:=b,c:=d,...);
  2493 
  2494 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2495 
  2496 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2497   [previously, this check worked only if the rewrite rule was unconditional]
  2498   Now rew can involve either definitions or equalities (either == or =).
  2499 
  2500 * case_tac provided for compatibility with HOL
  2501     (like the old excluded_middle_tac, but with subgoals swapped)
  2502 
  2503 
  2504 *** Internal programming interfaces ***
  2505 
  2506 * Pure: several new basic modules made available for general use, see
  2507 also src/Pure/README;
  2508 
  2509 * improved the theory data mechanism to support encapsulation (data
  2510 kind name replaced by private Object.kind, acting as authorization
  2511 key); new type-safe user interface via functor TheoryDataFun; generic
  2512 print_data function becomes basically useless;
  2513 
  2514 * removed global_names compatibility flag -- all theory declarations
  2515 are qualified by default;
  2516 
  2517 * module Pure/Syntax now offers quote / antiquote translation
  2518 functions (useful for Hoare logic etc. with implicit dependencies);
  2519 see HOL/ex/Antiquote for an example use;
  2520 
  2521 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2522 cterm -> thm;
  2523 
  2524 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2525 subgoal;
  2526 
  2527 * Display.print_goals function moved to Locale.print_goals;
  2528 
  2529 * standard print function for goals supports current_goals_markers
  2530 variable for marking begin of proof, end of proof, start of goal; the
  2531 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2532 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2533 for example;
  2534 
  2535 
  2536 
  2537 New in Isabelle98 (January 1998)
  2538 --------------------------------
  2539 
  2540 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2541 
  2542 * changed lexical syntax of terms / types: dots made part of long
  2543 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2544 
  2545 * simpset (and claset) reference variable replaced by functions
  2546 simpset / simpset_ref;
  2547 
  2548 * no longer supports theory aliases (via merge) and non-trivial
  2549 implicit merge of thms' signatures;
  2550 
  2551 * most internal names of constants changed due to qualified names;
  2552 
  2553 * changed Pure/Sequence interface (see Pure/seq.ML);
  2554 
  2555 
  2556 *** General Changes ***
  2557 
  2558 * hierachically structured name spaces (for consts, types, axms, thms
  2559 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2560 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2561 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2562 long_names for fully qualified output names; NOTE: ML programs
  2563 (special tactics, packages etc.) referring to internal names may have
  2564 to be adapted to cope with fully qualified names; in case of severe
  2565 backward campatibility problems try setting 'global_names' at compile
  2566 time to have enrything declared within a flat name space; one may also
  2567 fine tune name declarations in theories via the 'global' and 'local'
  2568 section;
  2569 
  2570 * reimplemented the implicit simpset and claset using the new anytype
  2571 data filed in signatures; references simpset:simpset ref etc. are
  2572 replaced by functions simpset:unit->simpset and
  2573 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2574 to patch your ML files accordingly;
  2575 
  2576 * HTML output now includes theory graph data for display with Java
  2577 applet or isatool browser; data generated automatically via isatool
  2578 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2579 
  2580 * defs may now be conditional; improved rewrite_goals_tac to handle
  2581 conditional equations;
  2582 
  2583 * defs now admits additional type arguments, using TYPE('a) syntax;
  2584 
  2585 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2586 creates a new theory node; implicit merge of thms' signatures is
  2587 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2588 transfer:theory->thm->thm in (rare) cases;
  2589 
  2590 * improved handling of draft signatures / theories; draft thms (and
  2591 ctyps, cterms) are automatically promoted to real ones;
  2592 
  2593 * slightly changed interfaces for oracles: admit many per theory, named
  2594 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2595 
  2596 * print_goals: optional output of const types (set show_consts and
  2597 show_types);
  2598 
  2599 * improved output of warnings (###) and errors (***);
  2600 
  2601 * subgoal_tac displays a warning if the new subgoal has type variables;
  2602 
  2603 * removed old README and Makefiles;
  2604 
  2605 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2606 
  2607 * removed obsolete init_pps and init_database;
  2608 
  2609 * deleted the obsolete tactical STATE, which was declared by
  2610     fun STATE tacfun st = tacfun st st;
  2611 
  2612 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2613 (which abbreviates $HOME);
  2614 
  2615 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2616 use isatool fixseq to adapt your ML programs (this works for fully
  2617 qualified references to the Sequence structure only!);
  2618 
  2619 * use_thy no longer requires writable current directory; it always
  2620 reloads .ML *and* .thy file, if either one is out of date;
  2621 
  2622 
  2623 *** Classical Reasoner ***
  2624 
  2625 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2626 tactics that use classical reasoning to simplify a subgoal without
  2627 splitting it into several subgoals;
  2628 
  2629 * Safe_tac: like safe_tac but uses the default claset;
  2630 
  2631 
  2632 *** Simplifier ***
  2633 
  2634 * added simplification meta rules:
  2635     (asm_)(full_)simplify: simpset -> thm -> thm;
  2636 
  2637 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2638 logics (again);
  2639 
  2640 * added prems argument to simplification procedures;
  2641 
  2642 * HOL, FOL, ZF: added infix function `addsplits':
  2643   instead of `<simpset> setloop (split_tac <thms>)'
  2644   you can simply write `<simpset> addsplits <thms>'
  2645 
  2646 
  2647 *** Syntax ***
  2648 
  2649 * TYPE('a) syntax for type reflection terms;
  2650 
  2651 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2652 
  2653 * pretty printer: changed order of mixfix annotation preference (again!);
  2654 
  2655 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2656 
  2657 
  2658 *** HOL ***
  2659 
  2660 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2661   with `addloop' of the simplifier to faciliate case splitting in premises.
  2662 
  2663 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2664 
  2665 * HOL/Auth: new protocol proofs including some for the Internet
  2666   protocol TLS;
  2667 
  2668 * HOL/Map: new theory of `maps' a la VDM;
  2669 
  2670 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2671 cancelling out common nat summands from =, <, <= (in)equalities, or
  2672 differences; simplification procedures nat_cancel_factor for
  2673 cancelling common factor from =, <, <= (in)equalities over natural
  2674 sums; nat_cancel contains both kinds of procedures, it is installed by
  2675 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2676 
  2677 * HOL/simplifier: terms of the form
  2678   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2679   are rewritten to
  2680   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2681   and those of the form
  2682   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2683   are rewritten to
  2684   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2685 
  2686 * HOL/datatype
  2687   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2688 
  2689   P(t_case f1 ... fn x) =
  2690      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2691         ...
  2692        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2693      )
  2694 
  2695   and a theorem `split_t_case_asm' of the form
  2696 
  2697   P(t_case f1 ... fn x) =
  2698     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2699         ...
  2700        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2701      )
  2702   which can be added to a simpset via `addsplits'. The existing theorems
  2703   expand_list_case and expand_option_case have been renamed to
  2704   split_list_case and split_option_case.
  2705 
  2706 * HOL/Arithmetic:
  2707   - `pred n' is automatically converted to `n-1'.
  2708     Users are strongly encouraged not to use `pred' any longer,
  2709     because it will disappear altogether at some point.
  2710   - Users are strongly encouraged to write "0 < n" rather than
  2711     "n ~= 0". Theorems and proof tools have been modified towards this
  2712     `standard'.
  2713 
  2714 * HOL/Lists:
  2715   the function "set_of_list" has been renamed "set" (and its theorems too);
  2716   the function "nth" now takes its arguments in the reverse order and
  2717   has acquired the infix notation "!" as in "xs!n".
  2718 
  2719 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2720 
  2721 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2722   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2723 
  2724 * HOL/record: extensible records with schematic structural subtyping
  2725 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2726 still lacks various theorems and concrete record syntax;
  2727 
  2728 
  2729 *** HOLCF ***
  2730 
  2731 * removed "axioms" and "generated by" sections;
  2732 
  2733 * replaced "ops" section by extended "consts" section, which is capable of
  2734   handling the continuous function space "->" directly;
  2735 
  2736 * domain package:
  2737   . proves theorems immediately and stores them in the theory,
  2738   . creates hierachical name space,
  2739   . now uses normal mixfix annotations (instead of cinfix...),
  2740   . minor changes to some names and values (for consistency),
  2741   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2742   . separator between mutual domain defs: changed "," to "and",
  2743   . improved handling of sort constraints;  now they have to
  2744     appear on the left-hand side of the equations only;
  2745 
  2746 * fixed LAM <x,y,zs>.b syntax;
  2747 
  2748 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2749 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2750 
  2751 
  2752 *** FOL and ZF ***
  2753 
  2754 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2755   with `addloop' of the simplifier to faciliate case splitting in premises.
  2756 
  2757 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2758 in HOL, they strip ALL and --> from proved theorems;
  2759 
  2760 
  2761 
  2762 New in Isabelle94-8 (May 1997)
  2763 ------------------------------
  2764 
  2765 *** General Changes ***
  2766 
  2767 * new utilities to build / run / maintain Isabelle etc. (in parts
  2768 still somewhat experimental); old Makefiles etc. still functional;
  2769 
  2770 * new 'Isabelle System Manual';
  2771 
  2772 * INSTALL text, together with ./configure and ./build scripts;
  2773 
  2774 * reimplemented type inference for greater efficiency, better error
  2775 messages and clean internal interface;
  2776 
  2777 * prlim command for dealing with lots of subgoals (an easier way of
  2778 setting goals_limit);
  2779 
  2780 
  2781 *** Syntax ***
  2782 
  2783 * supports alternative (named) syntax tables (parser and pretty
  2784 printer); internal interface is provided by add_modesyntax(_i);
  2785 
  2786 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2787 be used in conjunction with the Isabelle symbol font; uses the
  2788 "symbols" syntax table;
  2789 
  2790 * added token_translation interface (may translate name tokens in
  2791 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2792 the current print_mode); IMPORTANT: user print translation functions
  2793 are responsible for marking newly introduced bounds
  2794 (Syntax.mark_boundT);
  2795 
  2796 * token translations for modes "xterm" and "xterm_color" that display
  2797 names in bold, underline etc. or colors (which requires a color
  2798 version of xterm);
  2799 
  2800 * infixes may now be declared with names independent of their syntax;
  2801 
  2802 * added typed_print_translation (like print_translation, but may
  2803 access type of constant);
  2804 
  2805 
  2806 *** Classical Reasoner ***
  2807 
  2808 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2809 some limitations.  Blast_tac...
  2810   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2811   + ignores elimination rules that don't have the correct format
  2812         (the conclusion MUST be a formula variable)
  2813   + ignores types, which can make HOL proofs fail
  2814   + rules must not require higher-order unification, e.g. apply_type in ZF
  2815     [message "Function Var's argument not a bound variable" relates to this]
  2816   + its proof strategy is more general but can actually be slower
  2817 
  2818 * substitution with equality assumptions no longer permutes other
  2819 assumptions;
  2820 
  2821 * minor changes in semantics of addafter (now called addaltern); renamed
  2822 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2823 (and access functions for it);
  2824 
  2825 * improved combination of classical reasoner and simplifier:
  2826   + functions for handling clasimpsets
  2827   + improvement of addss: now the simplifier is called _after_ the
  2828     safe steps.
  2829   + safe variant of addss called addSss: uses safe simplifications
  2830     _during_ the safe steps. It is more complete as it allows multiple
  2831     instantiations of unknowns (e.g. with slow_tac).
  2832 
  2833 *** Simplifier ***
  2834 
  2835 * added interface for simplification procedures (functions that
  2836 produce *proven* rewrite rules on the fly, depending on current
  2837 redex);
  2838 
  2839 * ordering on terms as parameter (used for ordered rewriting);
  2840 
  2841 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2842 
  2843 * the solver is now split into a safe and an unsafe part.
  2844 This should be invisible for the normal user, except that the
  2845 functions setsolver and addsolver have been renamed to setSolver and
  2846 addSolver; added safe_asm_full_simp_tac;
  2847 
  2848 
  2849 *** HOL ***
  2850 
  2851 * a generic induction tactic `induct_tac' which works for all datatypes and
  2852 also for type `nat';
  2853 
  2854 * a generic case distinction tactic `exhaust_tac' which works for all
  2855 datatypes and also for type `nat';
  2856 
  2857 * each datatype comes with a function `size';
  2858 
  2859 * patterns in case expressions allow tuple patterns as arguments to
  2860 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2861 
  2862 * primrec now also works with type nat;
  2863 
  2864 * recdef: a new declaration form, allows general recursive functions to be
  2865 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2866 
  2867 * the constant for negation has been renamed from "not" to "Not" to
  2868 harmonize with FOL, ZF, LK, etc.;
  2869 
  2870 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2871 infinite lists;
  2872 
  2873 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2874 
  2875 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2876 problems in commutative rings, using axiomatic type classes for + and *;
  2877 
  2878 * more examples in HOL/MiniML and HOL/Auth;
  2879 
  2880 * more default rewrite rules for quantifiers, union/intersection;
  2881 
  2882 * a new constant `arbitrary == @x.False';
  2883 
  2884 * HOLCF/IOA replaces old HOL/IOA;
  2885 
  2886 * HOLCF changes: derived all rules and arities
  2887   + axiomatic type classes instead of classes
  2888   + typedef instead of faking type definitions
  2889   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2890   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2891   + eliminated the types void, one, tr
  2892   + use unit lift and bool lift (with translations) instead of one and tr
  2893   + eliminated blift from Lift3.thy (use Def instead of blift)
  2894   all eliminated rules are derived as theorems --> no visible changes ;
  2895 
  2896 
  2897 *** ZF ***
  2898 
  2899 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2900 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2901 as ZF_cs addSIs [equalityI];
  2902 
  2903 
  2904 
  2905 New in Isabelle94-7 (November 96)
  2906 ---------------------------------
  2907 
  2908 * allowing negative levels (as offsets) in prlev and choplev;
  2909 
  2910 * super-linear speedup for large simplifications;
  2911 
  2912 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2913 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2914 FAIL); can suppress it using the command Delsimps (ex_simps @
  2915 all_simps); De Morgan laws are also now included, by default;
  2916 
  2917 * improved printing of ==>  :  ~:
  2918 
  2919 * new object-logic "Sequents" adds linear logic, while replacing LK
  2920 and Modal (thanks to Sara Kalvala);
  2921 
  2922 * HOL/Auth: correctness proofs for authentication protocols;
  2923 
  2924 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2925 examples on HOL/Auth);
  2926 
  2927 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2928 the rewriter and classical reasoner simultaneously;
  2929 
  2930 * function uresult no longer returns theorems in "standard" format;
  2931 regain previous version by: val uresult = standard o uresult;
  2932 
  2933 
  2934 
  2935 New in Isabelle94-6
  2936 -------------------
  2937 
  2938 * oracles -- these establish an interface between Isabelle and trusted
  2939 external reasoners, which may deliver results as theorems;
  2940 
  2941 * proof objects (in particular record all uses of oracles);
  2942 
  2943 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2944 
  2945 * "constdefs" section in theory files;
  2946 
  2947 * "primrec" section (HOL) no longer requires names;
  2948 
  2949 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2950 
  2951 
  2952 
  2953 New in Isabelle94-5
  2954 -------------------
  2955 
  2956 * reduced space requirements;
  2957 
  2958 * automatic HTML generation from theories;
  2959 
  2960 * theory files no longer require "..." (quotes) around most types;
  2961 
  2962 * new examples, including two proofs of the Church-Rosser theorem;
  2963 
  2964 * non-curried (1994) version of HOL is no longer distributed;
  2965 
  2966 
  2967 
  2968 New in Isabelle94-4
  2969 -------------------
  2970 
  2971 * greatly reduced space requirements;
  2972 
  2973 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2974 
  2975 * searchable theorem database (see the section "Retrieving theorems" on
  2976 page 8 of the Reference Manual);
  2977 
  2978 * new examples, including Grabczewski's monumental case study of the
  2979 Axiom of Choice;
  2980 
  2981 * The previous version of HOL renamed to Old_HOL;
  2982 
  2983 * The new version of HOL (previously called CHOL) uses a curried syntax
  2984 for functions.  Application looks like f a b instead of f(a,b);
  2985 
  2986 * Mutually recursive inductive definitions finally work in HOL;
  2987 
  2988 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2989 translates to the operator "split";
  2990 
  2991 
  2992 
  2993 New in Isabelle94-3
  2994 -------------------
  2995 
  2996 * new infix operator, addss, allowing the classical reasoner to
  2997 perform simplification at each step of its search.  Example:
  2998         fast_tac (cs addss ss)
  2999 
  3000 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3001 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3002 look like (a,b) instead of <a,b>;
  3003 
  3004 * PLEASE NOTE: CHOL will eventually replace HOL!
  3005 
  3006 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3007 It translates to the operator "split".  A new theory of integers is available;
  3008 
  3009 * In ZF, integer numerals now denote two's-complement binary integers.
  3010 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3011 
  3012 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3013 of the Axiom of Choice;
  3014 
  3015 
  3016 
  3017 New in Isabelle94-2
  3018 -------------------
  3019 
  3020 * Significantly faster resolution;
  3021 
  3022 * the different sections in a .thy file can now be mixed and repeated
  3023 freely;
  3024 
  3025 * Database of theorems for FOL, HOL and ZF.  New
  3026 commands including qed, qed_goal and bind_thm store theorems in the database.
  3027 
  3028 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3029 a given theory (thms_of), or find out what theory a theorem was proved in
  3030 (theory_of_thm);
  3031 
  3032 * Bugs fixed in the inductive definition and datatype packages;
  3033 
  3034 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3035 and HOL_dup_cs obsolete;
  3036 
  3037 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3038 have been removed;
  3039 
  3040 * Simpler definition of function space in ZF;
  3041 
  3042 * new results about cardinal and ordinal arithmetic in ZF;
  3043 
  3044 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3045 types;
  3046 
  3047 
  3048 $Id$