NEWS
author wenzelm
Sat Apr 16 18:55:28 2005 +0200 (2005-04-16)
changeset 15744 daa84ebbdf94
parent 15727 b43d82139a6c
child 15763 b901a127ac73
permissions -rw-r--r--
Pure: command 'no_syntax' removes grammar declarations;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * ML: The type Library.option is no more, along with the exception
    10   Library.OPTION: Isabelle now uses the standard option type.  The
    11   functions the, is_some, is_none, etc. are still in Library, but
    12   the constructors are now SOME and NONE instead of Some and None.
    13   They raise the exception Option.
    14 
    15 * ML: The exception LIST is no more, the standard exceptions Empty and
    16   Subscript, as well as Library.UnequalLengths are used instead.  This
    17   means that function like Library.hd and Library.tl are gone, as the
    18   standard hd and tl functions suffice.
    19 
    20   A number of basic functions are now no longer exported to the top ML
    21   level, as they are variants of standard functions.  The following
    22   suggests how one can translate existing code:
    23 
    24     the x = valOf x
    25     if_none x y = getOpt(x,y)
    26     is_some x = isSome x
    27     apsome f x = Option.map f x
    28     rev_append xs ys = List.revAppend(xs,ys)
    29     nth_elem(i,xs) = List.nth(xs,i)
    30     last_elem xs = List.last xs
    31     flat xss = List.concat xss
    32     seq fs = app fs
    33     partition P xs = List.partition P xs
    34     filter P xs = List.filter P xs
    35     mapfilter f xs = List.mapPartial f xs
    36 
    37   The final four functions, take, drop, foldl, and foldr, are somewhat
    38   more complicated (especially the semantics of take and drop differ
    39   from the standard).
    40 
    41   A simple solution to broken code is to include "open Library" at the
    42   beginning of a structure.  Everything after that will be as before.
    43 
    44 * Theory headers: the new header syntax for Isar theories is
    45 
    46   theory <name>
    47   imports <theory1> ... <theoryn>
    48   begin
    49 
    50   optionally also with a "files" section. The syntax
    51 
    52   theory <name> = <theory1> + ... + <theoryn>:
    53 
    54   will still be supported for some time but will eventually disappear.
    55   The syntax of old-style theories has not changed.
    56 
    57 * Theory loader: parent theories can now also be referred to via
    58   relative and absolute paths.
    59 
    60 * Provers/quasi.ML:  new transitivity reasoners for transitivity only
    61   and quasi orders.
    62 
    63 * Provers/trancl.ML:  new transitivity reasoner for transitive and
    64   reflexive-transitive closure of relations.
    65 
    66 * Provers/blast.ML:  new reference depth_limit to make blast's depth
    67   limit (previously hard-coded with a value of 20) user-definable.
    68 
    69 * Provers: new version of the subst method, for single-step rewriting: it now
    70   works in bound variable contexts. New is subst (asm), for rewriting an
    71   assumption. Thanks to Lucas Dixon! INCOMPATIBILITY: may rewrite a different
    72   subterm than the original subst method, which is still available under the
    73   name simplesubst.
    74 
    75 * Pure: thin_tac now works even if the assumption being deleted contains !! or ==>. 
    76   More generally, erule now works even if the major premise of the elimination rule
    77   contains !! or ==>.
    78 
    79 * Pure: considerably improved version of 'constdefs' command.  Now
    80   performs automatic type-inference of declared constants; additional
    81   support for local structure declarations (cf. locales and HOL
    82   records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    83   to observe strictly sequential dependencies of definitions within a
    84   single 'constdefs' section; moreover, the declared name needs to be
    85   an identifier.  If all fails, consider to fall back on 'consts' and
    86   'defs' separately.
    87 
    88 * Pure: improved indexed syntax and implicit structures.  First of
    89   all, indexed syntax provides a notational device for subscripted
    90   application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    91   expressions.  Secondly, in a local context with structure
    92   declarations, number indexes \<^sub>n or the empty index (default
    93   number 1) refer to a certain fixed variable implicitly; option
    94   show_structs controls printing of implicit structures.  Typical
    95   applications of these concepts involve record types and locales.
    96 
    97 * Pure: clear separation of logical types and nonterminals, where the
    98   latter may only occur in 'syntax' specifications or type
    99   abbreviations.  Before that distinction was only partially
   100   implemented via type class "logic" vs. "{}".  Potential
   101   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
   102   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
   103   specifications may require further adaption (e.g. Cube/Base.thy).
   104 
   105 * Pure: removed obsolete type class "logic", use the top sort {}
   106   instead.  Note that non-logical types should be declared as
   107   'nonterminals' rather than 'types'.  INCOMPATIBILITY for new
   108   object-logic specifications.
   109 
   110 * Pure: command 'no_syntax' removes grammar declarations (and
   111   translations) resulting from the given syntax specification, which
   112   is interpreted in the same manner as for the 'syntax' command.
   113 
   114 * Pure: print_tac now outputs the goal through the trace channel.
   115 
   116 * Pure: reference Namespace.unique_names included.  If true the
   117   (shortest) namespace-prefix is printed to disambiguate conflicts (as
   118   yet). If false the first entry wins (as during parsing). Default
   119   value is true.
   120 
   121 * Pure: tuned internal renaming of symbolic identifiers -- attach
   122   primes instead of base 26 numbers.
   123 
   124 * Pure: new flag show_var_qmarks to control printing of leading
   125   question marks of variable names.
   126 
   127 * Pure/Syntax: inner syntax includes (*(*nested*) comments*).
   128 
   129 * Pure/Syntax: pretty pinter now supports unbreakable blocks,
   130   specified in mixfix annotations as "(00...)".
   131 
   132 * Pure/Syntax: 'advanced' translation functions (parse_translation
   133   etc.) may depend on the signature of the theory context being
   134   presently used for parsing/printing, see also isar-ref manual.
   135 
   136 * Pure/Simplifier: simplification procedures may now take the current
   137   simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   138   interface), which is very useful for calling the Simplifier
   139   recursively.  Minor INCOMPATIBILITY: the 'prems' argument of
   140   simprocs is gone -- use prems_of_ss on the simpset instead.
   141   Moreover, the low-level mk_simproc no longer applies Logic.varify
   142   internally, to allow for use in a context of fixed variables.
   143 
   144 * Pure/Simplifier: Command "find_rewrites" takes a string and lists all
   145   equality theorems (not just those declared as simp!) whose left-hand
   146   side matches the term given via the string. In PG the command can be
   147   activated via Isabelle -> Show me -> matching rewrites.
   148 
   149 * Isar debugging: new reference Toplevel.debug; default false.
   150   Set to make printing of exceptions THM, TERM, TYPE and THEORY more verbose.
   151   
   152 * Locales:
   153   - "includes" disallowed in declaration of named locales (command "locale").
   154   - Fixed parameter management in theorem generation for goals with "includes".
   155     INCOMPATIBILITY: rarely, the generated theorem statement is different.
   156 
   157 * Locales:  new commands for the interpretation of locale expressions
   158   in theories (interpretation) and proof contexts (interpret).  These take an
   159   instantiation of the locale parameters and compute proof obligations from
   160   the instantiated specification.  After the obligations have been discharged,
   161   the instantiated theorems of the locale are added to the theory or proof
   162   context.  Interpretation is smart in that already active interpretations
   163   do not occur in proof obligations, neither are instantiated theorems stored
   164   in duplicate.
   165   Use print_interps to inspect active interpretations of a particular locale.
   166 
   167 * Locales: proper static binding of attribute syntax -- i.e. types /
   168   terms / facts mentioned as arguments are always those of the locale
   169   definition context, independently of the context of later
   170   invocations.  Moreover, locale operations (renaming and type / term
   171   instantiation) are applied to attribute arguments as expected.
   172 
   173   INCOMPATIBILITY of the ML interface: always pass Attrib.src instead
   174   of actual attributes; rare situations may require Attrib.attribute
   175   to embed those attributes into Attrib.src that lack concrete syntax.
   176 
   177   Attribute implementations need to cooperate properly with the static
   178   binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   179   Attrib.XXX_thm etc. already do the right thing without further
   180   intervention.  Only unusual applications -- such as "where" or "of"
   181   (cf. src/Pure/Isar/attrib.ML), which process arguments depending
   182   both on the context and the facts involved -- may have to assign
   183   parsed values to argument tokens explicitly.
   184 
   185 * Attributes 'induct' and 'cases': type or set names may now be
   186   locally fixed variables as well.
   187 
   188 * Isar: new syntax 'name(i-j, i-, i, ...)' for referring to specific
   189   selections of theorems in named facts via indices.
   190 
   191 
   192 *** Document preparation ***
   193 
   194 * New antiquotations @{lhs thm} and @{rhs thm} printing the lhs/rhs of
   195   definitions, equations, inequations etc.
   196 
   197 * Antiquotations now provide the option 'locale=NAME' to specify an
   198   alternative context used for evaluating and printing the subsequent
   199   argument, as in @{thm [locale=LC] fold_commute}, for example.
   200 
   201 * Commands 'display_drafts' and 'print_drafts' perform simple output
   202   of raw sources.  Only those symbols that do not require additional
   203   LaTeX packages (depending on comments in isabellesym.sty) are
   204   displayed properly, everything else is left verbatim.  We use
   205   isatool display and isatool print as front ends; these are subject
   206   to the DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively.
   207 
   208 * Proof scripts as well as some other commands such as ML or
   209   parse/print_translation can now be hidden in the document.  Hiding
   210   is enabled by default, and can be disabled either via the option '-H
   211   false' of isatool usedir or by resetting the reference variable
   212   IsarOutput.hide_commands. Additional commands to be hidden may be
   213   declared using IsarOutput.add_hidden_commands.
   214 
   215 
   216 *** HOL ***
   217 
   218 * Datatype induction via method `induct' now preserves the name of the
   219   induction variable. For example, when proving P(xs::'a list) by induction
   220   on xs, the induction step is now P(xs) ==> P(a#xs) rather than
   221   P(list) ==> P(a#list) as previously.
   222 
   223 * HOL/record: reimplementation of records. Improved scalability for
   224   records with many fields, avoiding performance problems for type
   225   inference. Records are no longer composed of nested field types, but
   226   of nested extension types. Therefore the record type only grows
   227   linear in the number of extensions and not in the number of fields.
   228   The top-level (users) view on records is preserved.  Potential
   229   INCOMPATIBILITY only in strange cases, where the theory depends on
   230   the old record representation. The type generated for a record is
   231   called <record_name>_ext_type.
   232 
   233 * HOL/record: Reference record_quick_and_dirty_sensitive can be
   234   enabled to skip the proofs triggered by a record definition or a
   235   simproc (if quick_and_dirty is enabled). Definitions of large
   236   records can take quite long.
   237 
   238 * HOL/record: "record_upd_simproc" for simplification of multiple
   239   record updates enabled by default.  Moreover, trivial updates are
   240   also removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   241   occasionally, since simplification is more powerful by default.
   242 
   243 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
   244 
   245   syntax (epsilon)
   246     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   247 
   248   The symbol \<some> is displayed as the alternative epsilon of LaTeX
   249   and x-symbol; use option '-m epsilon' to get it actually printed.
   250   Moreover, the mathematically important symbolic identifier
   251   \<epsilon> becomes available as variable, constant etc.
   252 
   253 * HOL: "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   254   Similarly for all quantifiers: "ALL x > y" etc.
   255   The x-symbol for >= is \<ge>.
   256 
   257 * HOL/Set: "{x:A. P}" abbreviates "{x. x:A & P}"
   258            (and similarly for "\<in>" instead of ":")
   259 
   260 * HOL/SetInterval: The syntax for open intervals has changed:
   261 
   262   Old         New
   263   {..n(}   -> {..<n}
   264   {)n..}   -> {n<..}
   265   {m..n(}  -> {m..<n}
   266   {)m..n}  -> {m<..n}
   267   {)m..n(} -> {m<..<n}
   268 
   269   The old syntax is still supported but will disappear in the future.
   270   For conversion use the following emacs search and replace patterns:
   271 
   272   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   273   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   274 
   275   They are not perfect but work quite well.
   276 
   277 * HOL: The syntax for 'setsum', summation over finite sets, has changed:
   278 
   279   The syntax for 'setsum (%x. e) A' used to be '\<Sum>x:A. e'
   280   and is now either 'SUM x:A. e' or '\<Sum>x\<in>A. e'.
   281 
   282   There is new syntax for summation over finite sets:
   283 
   284   '\<Sum>x | P. e'    is the same as  'setsum (%x. e) {x. P}'
   285   '\<Sum>x=a..b. e'   is the same as  'setsum (%x. e) {a..b}'
   286   '\<Sum>x=a..<b. e'  is the same as  'setsum (%x. e) {a..<b}'
   287   '\<Sum>x<k. e'      is the same as  'setsum (%x. e) {..<k}'
   288 
   289   Function 'Summation' over nat is gone, its syntax '\<Sum>i<k. e'
   290   now translates into 'setsum' as above.
   291 
   292 * HOL: Finite set induction: In Isar proofs, the insert case is now
   293   "case (insert x F)" instead of the old counterintuitive "case (insert F x)".
   294 
   295 * HOL/Simplifier:
   296 
   297   - Is now set up to reason about transitivity chains involving "trancl"
   298   (r^+) and "rtrancl" (r^*) by setting up tactics provided by
   299   Provers/trancl.ML as additional solvers.  INCOMPATIBILITY: old proofs break
   300   occasionally as simplification may now solve more goals than previously.
   301 
   302   - Converts x <= y into x = y if assumption y <= x is present.  Works for
   303   all partial orders (class "order"), in particular numbers and sets. For
   304   linear orders (e.g. numbers) it treats ~ x < y just like y <= x.
   305 
   306   - Simproc for "let x = a in f x"
   307   If a is a free or bound variable or a constant then the let is unfolded.
   308   Otherwise first a is simplified to a', and then f a' is simplified to
   309   g. If possible we abstract a' from g arriving at "let x = a' in g' x",
   310   otherwise we unfold the let and arrive at g. The simproc can be 
   311   enabled/disabled by the reference use_let_simproc. Potential
   312   INCOMPATIBILITY since simplification is more powerful by default.
   313  
   314 
   315 *** HOLCF ***
   316 
   317 * HOLCF: discontinued special version of 'constdefs' (which used to
   318   support continuous functions) in favor of the general Pure one with
   319   full type-inference.
   320 
   321 
   322 *** ZF ***
   323 
   324 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the
   325   First Isomorphism Theorem (on quotienting by the kernel of a
   326   homomorphism).
   327 
   328 * ZF/Simplifier: install second copy of type solver that actually
   329   makes use of TC rules declared to Isar proof contexts (or locales);
   330   the old version is still required for ML proof scripts.
   331 
   332 
   333 *** System ***
   334 
   335 * HOL: isatool dimacs2hol converts files in DIMACS CNF format
   336   (containing Boolean satisfiability problems) into Isabelle/HOL
   337   theories.
   338 
   339 * isatool usedir: option -f allows specification of the ML file to be
   340   used by Isabelle; default is ROOT.ML.
   341 
   342 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   343   isatool doc, isatool mkdir, display_drafts etc.).
   344 
   345 
   346 *** ML ***
   347 
   348 * Pure: output via the Isabelle channels of writeln/warning/error
   349   etc. is now passed through Output.output, with a hook for arbitrary
   350   transformations depending on the print_mode (cf. Output.add_mode --
   351   the first active mode that provides a output function wins).
   352   Already formatted output may be embedded into further text via
   353   Output.raw; the result of Pretty.string_of/str_of and derived
   354   functions (string_of_term/cterm/thm etc.) is already marked raw to
   355   accommodate easy composition of diagnostic messages etc.
   356   Programmers rarely need to care about Output.output or Output.raw at
   357   all, with some notable exceptions: Output.output is required when
   358   bypassing the standard channels (writeln etc.), or in token
   359   translations to produce properly formatted results; Output.raw is
   360   required when capturing already output material that will eventually
   361   be presented to the user a second time.  For the default print mode,
   362   both Output.output and Output.raw have no effect.
   363 
   364 * Provers: Simplifier and Classical Reasoner now support proof context
   365   dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   366   components are stored in the theory and patched into the
   367   simpset/claset when used in an Isar proof context.  Context
   368   dependent components are maintained by the following theory
   369   operations:
   370 
   371     Simplifier.add_context_simprocs
   372     Simplifier.del_context_simprocs
   373     Simplifier.set_context_subgoaler
   374     Simplifier.reset_context_subgoaler
   375     Simplifier.add_context_looper
   376     Simplifier.del_context_looper
   377     Simplifier.add_context_unsafe_solver
   378     Simplifier.add_context_safe_solver
   379 
   380     Classical.add_context_safe_wrapper
   381     Classical.del_context_safe_wrapper
   382     Classical.add_context_unsafe_wrapper
   383     Classical.del_context_unsafe_wrapper
   384 
   385   IMPORTANT NOTE: proof tools (methods etc.) need to use
   386   local_simpset_of and local_claset_of to instead of the primitive
   387   Simplifier.get_local_simpset and Classical.get_local_claset,
   388   respectively, in order to see the context dependent fields!
   389 
   390 
   391 
   392 New in Isabelle2004 (April 2004)
   393 --------------------------------
   394 
   395 *** General ***
   396 
   397 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   398   Replaces linorder.ML.
   399 
   400 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   401   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   402   (\<a>...\<z>), are now considered normal letters, and can therefore
   403   be used anywhere where an ASCII letter (a...zA...Z) has until
   404   now. COMPATIBILITY: This obviously changes the parsing of some
   405   terms, especially where a symbol has been used as a binder, say
   406   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   407   as an identifier.  Fix it by inserting a space around former
   408   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   409   existing theory and ML files.
   410 
   411 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   412 
   413 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   414   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   415   a normal (but invisible) letter. For multiple letter subscripts repeat
   416   \<^isub> like this: x\<^isub>1\<^isub>2.
   417 
   418 * Pure: There are now sub-/superscripts that can span more than one
   419   character. Text between \<^bsub> and \<^esub> is set in subscript in
   420   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   421   superscript. The new control characters are not identifier parts.
   422 
   423 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   424   content of "..." to the latex file instead of \isacntrl... . The "..."
   425   may consist of any printable characters excluding the end bracket >.
   426 
   427 * Pure: Using new Isar command "finalconsts" (or the ML functions
   428   Theory.add_finals or Theory.add_finals_i) it is now possible to
   429   declare constants "final", which prevents their being given a definition
   430   later.  It is useful for constants whose behaviour is fixed axiomatically
   431   rather than definitionally, such as the meta-logic connectives.
   432 
   433 * Pure: 'instance' now handles general arities with general sorts
   434   (i.e. intersections of classes),
   435 
   436 * Presentation: generated HTML now uses a CSS style sheet to make layout
   437   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   438   It can be changed to alter the colors/layout of generated pages.
   439 
   440 
   441 *** Isar ***
   442 
   443 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   444   cut_tac, subgoal_tac and thin_tac:
   445   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   446     locales are no longer forced to write Isar proof scripts.
   447     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   448     emulations.
   449   - INCOMPATIBILITY: names of variables to be instantiated may no
   450     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   451     This is consistent with the instantiation attribute "where".
   452 
   453 * Attributes "where" and "of":
   454   - Now take type variables of instantiated theorem into account when reading
   455     the instantiation string.  This fixes a bug that caused instantiated
   456     theorems to have too special types in some circumstances.
   457   - "where" permits explicit instantiations of type variables.
   458 
   459 * Calculation commands "moreover" and "also" no longer interfere with
   460   current facts ("this"), admitting arbitrary combinations with "then"
   461   and derived forms.
   462 
   463 * Locales:
   464   - Goal statements involving the context element "includes" no longer
   465     generate theorems with internal delta predicates (those ending on
   466     "_axioms") in the premise.
   467     Resolve particular premise with <locale>.intro to obtain old form.
   468   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   469     specification and "includes" elements in goal statement.
   470   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   471     [intro?] and [elim?] (respectively) by default.
   472   - Experimental command for instantiation of locales in proof contexts:
   473         instantiate <label>[<attrs>]: <loc>
   474     Instantiates locale <loc> and adds all its theorems to the current context
   475     taking into account their attributes.  Label and attrs are optional
   476     modifiers, like in theorem declarations.  If present, names of
   477     instantiated theorems are qualified with <label>, and the attributes
   478     <attrs> are applied after any attributes these theorems might have already.
   479       If the locale has assumptions, a chained fact of the form
   480     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   481     are derived.  The command does not support old-style locales declared
   482     with "locale (open)".
   483       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   484 
   485 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   486   (Isar) contexts.
   487 
   488 
   489 *** HOL ***
   490 
   491 * Proof import: new image HOL4 contains the imported library from
   492   the HOL4 system with about 2500 theorems. It is imported by
   493   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   494   can be used like any other Isabelle image.  See
   495   HOL/Import/HOL/README for more information.
   496 
   497 * Simplifier:
   498   - Much improved handling of linear and partial orders.
   499     Reasoners for linear and partial orders are set up for type classes
   500     "linorder" and "order" respectively, and are added to the default simpset
   501     as solvers.  This means that the simplifier can build transitivity chains
   502     to solve goals from the assumptions.
   503   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   504     of blast or auto after simplification become unnecessary because the goal
   505     is solved by simplification already.
   506 
   507 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   508     all proved in axiomatic type classes for semirings, rings and fields.
   509 
   510 * Numerics:
   511   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   512     now formalized using the Ring_and_Field theory mentioned above.
   513   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   514     than before, because now they are set up once in a generic manner.
   515   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   516     Look for the general versions in Ring_and_Field (and Power if they concern
   517     exponentiation).
   518 
   519 * Type "rat" of the rational numbers is now available in HOL-Complex.
   520 
   521 * Records:
   522   - Record types are now by default printed with their type abbreviation
   523     instead of the list of all field types. This can be configured via
   524     the reference "print_record_type_abbr".
   525   - Simproc "record_upd_simproc" for simplification of multiple updates added
   526     (not enabled by default).
   527   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   528     EX x. x = sel r to True (not enabled by default).
   529   - Tactic "record_split_simp_tac" to split and simplify records added.
   530 
   531 * 'specification' command added, allowing for definition by
   532   specification.  There is also an 'ax_specification' command that
   533   introduces the new constants axiomatically.
   534 
   535 * arith(_tac) is now able to generate counterexamples for reals as well.
   536 
   537 * HOL-Algebra: new locale "ring" for non-commutative rings.
   538 
   539 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   540   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   541 
   542 * HOL-Matrix: a first theory for matrices in HOL with an application of
   543   matrix theory to linear programming.
   544 
   545 * Unions and Intersections:
   546   The latex output syntax of UN and INT has been changed
   547   from "\Union x \in A. B" to "\Union_{x \in A} B"
   548   i.e. the index formulae has become a subscript.
   549   Similarly for "\Union x. B", and for \Inter instead of \Union.
   550 
   551 * Unions and Intersections over Intervals:
   552   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   553   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   554   like in normal math, and corresponding versions for < and for intersection.
   555 
   556 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   557   lexicographic dictonary ordering has been added as "lexord".
   558 
   559 * ML: the legacy theory structures Int and List have been removed. They had
   560   conflicted with ML Basis Library structures having the same names.
   561 
   562 * 'refute' command added to search for (finite) countermodels.  Only works
   563   for a fragment of HOL.  The installation of an external SAT solver is
   564   highly recommended.  See "HOL/Refute.thy" for details.
   565 
   566 * 'quickcheck' command: Allows to find counterexamples by evaluating
   567   formulae under an assignment of free variables to random values.
   568   In contrast to 'refute', it can deal with inductive datatypes,
   569   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   570   for examples.
   571 
   572 
   573 *** HOLCF ***
   574 
   575 * Streams now come with concatenation and are part of the HOLCF image
   576 
   577 
   578 
   579 New in Isabelle2003 (May 2003)
   580 ------------------------------
   581 
   582 *** General ***
   583 
   584 * Provers/simplifier:
   585 
   586   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   587     Assumptions are now subject to complete mutual simplification,
   588     not just from left to right. The simplifier now preserves
   589     the order of assumptions.
   590 
   591     Potential INCOMPATIBILITY:
   592 
   593     -- simp sometimes diverges where the old version did
   594        not, e.g. invoking simp on the goal
   595 
   596         [| P (f x); y = x; f x = f y |] ==> Q
   597 
   598        now gives rise to the infinite reduction sequence
   599 
   600         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   601 
   602        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   603        kind of problem.
   604 
   605     -- Tactics combining classical reasoner and simplification (such as auto)
   606        are also affected by this change, because many of them rely on
   607        simp. They may sometimes diverge as well or yield a different numbers
   608        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   609        in case of problems. Sometimes subsequent calls to the classical
   610        reasoner will fail because a preceeding call to the simplifier too
   611        eagerly simplified the goal, e.g. deleted redundant premises.
   612 
   613   - The simplifier trace now shows the names of the applied rewrite rules
   614 
   615   - You can limit the number of recursive invocations of the simplifier
   616     during conditional rewriting (where the simplifie tries to solve the
   617     conditions before applying the rewrite rule):
   618     ML "simp_depth_limit := n"
   619     where n is an integer. Thus you can force termination where previously
   620     the simplifier would diverge.
   621 
   622   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   623 
   624   - No longer aborts on failed congruence proof.  Instead, the
   625     congruence is ignored.
   626 
   627 * Pure: New generic framework for extracting programs from constructive
   628   proofs. See HOL/Extraction.thy for an example instantiation, as well
   629   as HOL/Extraction for some case studies.
   630 
   631 * Pure: The main goal of the proof state is no longer shown by default, only
   632 the subgoals. This behaviour is controlled by a new flag.
   633    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   634 (ML: Proof.show_main_goal).
   635 
   636 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   637 rules whose conclusion matches subgoal 1:
   638       PG menu: Isabelle/Isar -> Show me -> matching rules
   639 The rules are ordered by how closely they match the subgoal.
   640 In particular, rules that solve a subgoal outright are displayed first
   641 (or rather last, the way they are printed).
   642 (ML: ProofGeneral.print_intros())
   643 
   644 * Pure: New flag trace_unify_fail causes unification to print
   645 diagnostic information (PG: in trace buffer) when it fails. This is
   646 useful for figuring out why single step proofs like rule, erule or
   647 assumption failed.
   648 
   649 * Pure: Locale specifications now produce predicate definitions
   650 according to the body of text (covering assumptions modulo local
   651 definitions); predicate "loc_axioms" covers newly introduced text,
   652 while "loc" is cumulative wrt. all included locale expressions; the
   653 latter view is presented only on export into the global theory
   654 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   655 on the old view without predicates;
   656 
   657 * Pure: predefined locales "var" and "struct" are useful for sharing
   658 parameters (as in CASL, for example); just specify something like
   659 ``var x + var y + struct M'' as import;
   660 
   661 * Pure: improved thms_containing: proper indexing of facts instead of
   662 raw theorems; check validity of results wrt. current name space;
   663 include local facts of proof configuration (also covers active
   664 locales), cover fixed variables in index; may use "_" in term
   665 specification; an optional limit for the number of printed facts may
   666 be given (the default is 40);
   667 
   668 * Pure: disallow duplicate fact bindings within new-style theory files
   669 (batch-mode only);
   670 
   671 * Provers: improved induct method: assumptions introduced by case
   672 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   673 the goal statement); "foo" still refers to all facts collectively;
   674 
   675 * Provers: the function blast.overloaded has been removed: all constants
   676 are regarded as potentially overloaded, which improves robustness in exchange
   677 for slight decrease in efficiency;
   678 
   679 * Provers/linorder: New generic prover for transitivity reasoning over
   680 linear orders.  Note: this prover is not efficient!
   681 
   682 * Isar: preview of problems to finish 'show' now produce an error
   683 rather than just a warning (in interactive mode);
   684 
   685 
   686 *** HOL ***
   687 
   688 * arith(_tac)
   689 
   690  - Produces a counter example if it cannot prove a goal.
   691    Note that the counter example may be spurious if the goal is not a formula
   692    of quantifier-free linear arithmetic.
   693    In ProofGeneral the counter example appears in the trace buffer.
   694 
   695  - Knows about div k and mod k where k is a numeral of type nat or int.
   696 
   697  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   698    linear arithmetic fails. This takes account of quantifiers and divisibility.
   699    Presburger arithmetic can also be called explicitly via presburger(_tac).
   700 
   701 * simp's arithmetic capabilities have been enhanced a bit: it now
   702 takes ~= in premises into account (by performing a case split);
   703 
   704 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   705 are distributed over a sum of terms;
   706 
   707 * New tactic "trans_tac" and method "trans" instantiate
   708 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   709 "<=", "<" and "=").
   710 
   711 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   712 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   713 
   714 * 'typedef' command has new option "open" to suppress the set
   715 definition;
   716 
   717 * functions Min and Max on finite sets have been introduced (theory
   718 Finite_Set);
   719 
   720 * attribute [symmetric] now works for relations as well; it turns
   721 (x,y) : R^-1 into (y,x) : R, and vice versa;
   722 
   723 * induct over a !!-quantified statement (say !!x1..xn):
   724   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   725 
   726 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   727 %x. None. Warning: empty_def now refers to the previously hidden definition
   728 of the empty set.
   729 
   730 * Algebra: formalization of classical algebra.  Intended as base for
   731 any algebraic development in Isabelle.  Currently covers group theory
   732 (up to Sylow's theorem) and ring theory (Universal Property of
   733 Univariate Polynomials).  Contributions welcome;
   734 
   735 * GroupTheory: deleted, since its material has been moved to Algebra;
   736 
   737 * Complex: new directory of the complex numbers with numeric constants,
   738 nonstandard complex numbers, and some complex analysis, standard and
   739 nonstandard (Jacques Fleuriot);
   740 
   741 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   742 
   743 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   744 Fleuriot);
   745 
   746 * Real/HahnBanach: updated and adapted to locales;
   747 
   748 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   749 Gray and Kramer);
   750 
   751 * UNITY: added the Meier-Sanders theory of progress sets;
   752 
   753 * MicroJava: bytecode verifier and lightweight bytecode verifier
   754 as abstract algorithms, instantiated to the JVM;
   755 
   756 * Bali: Java source language formalization. Type system, operational
   757 semantics, axiomatic semantics. Supported language features:
   758 classes, interfaces, objects,virtual methods, static methods,
   759 static/instance fields, arrays, access modifiers, definite
   760 assignment, exceptions.
   761 
   762 
   763 *** ZF ***
   764 
   765 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   766 universe, etc.);
   767 
   768 * Main ZF: virtually all theories converted to new-style format;
   769 
   770 
   771 *** ML ***
   772 
   773 * Pure: Tactic.prove provides sane interface for internal proofs;
   774 omits the infamous "standard" operation, so this is more appropriate
   775 than prove_goalw_cterm in many situations (e.g. in simprocs);
   776 
   777 * Pure: improved error reporting of simprocs;
   778 
   779 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   780 up simprocs;
   781 
   782 
   783 *** Document preparation ***
   784 
   785 * uses \par instead of \\ for line breaks in theory text. This may
   786 shift some page breaks in large documents. To get the old behaviour
   787 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   788 
   789 * minimized dependencies of isabelle.sty and isabellesym.sty on
   790 other packages
   791 
   792 * \<euro> now needs package babel/greek instead of marvosym (which
   793 broke \Rightarrow)
   794 
   795 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   796 textcomp package)
   797 
   798 
   799 
   800 New in Isabelle2002 (March 2002)
   801 --------------------------------
   802 
   803 *** Document preparation ***
   804 
   805 * greatly simplified document preparation setup, including more
   806 graceful interpretation of isatool usedir -i/-d/-D options, and more
   807 instructive isatool mkdir; users should basically be able to get
   808 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   809 users may run a separate document processing stage manually like this:
   810 "isatool usedir -D output HOL Test && isatool document Test/output";
   811 
   812 * theory dependency graph may now be incorporated into documents;
   813 isatool usedir -g true will produce session_graph.eps/.pdf for use
   814 with \includegraphics of LaTeX;
   815 
   816 * proper spacing of consecutive markup elements, especially text
   817 blocks after section headings;
   818 
   819 * support bold style (for single symbols only), input syntax is like
   820 this: "\<^bold>\<alpha>" or "\<^bold>A";
   821 
   822 * \<bullet> is now output as bold \cdot by default, which looks much
   823 better in printed text;
   824 
   825 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   826 note that these symbols are currently unavailable in Proof General /
   827 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   828 
   829 * isatool latex no longer depends on changed TEXINPUTS, instead
   830 isatool document copies the Isabelle style files to the target
   831 location;
   832 
   833 
   834 *** Isar ***
   835 
   836 * Pure/Provers: improved proof by cases and induction;
   837   - 'case' command admits impromptu naming of parameters (such as
   838     "case (Suc n)");
   839   - 'induct' method divinates rule instantiation from the inductive
   840     claim; no longer requires excessive ?P bindings for proper
   841     instantiation of cases;
   842   - 'induct' method properly enumerates all possibilities of set/type
   843     rules; as a consequence facts may be also passed through *type*
   844     rules without further ado;
   845   - 'induct' method now derives symbolic cases from the *rulified*
   846     rule (before it used to rulify cases stemming from the internal
   847     atomized version); this means that the context of a non-atomic
   848     statement becomes is included in the hypothesis, avoiding the
   849     slightly cumbersome show "PROP ?case" form;
   850   - 'induct' may now use elim-style induction rules without chaining
   851     facts, using ``missing'' premises from the goal state; this allows
   852     rules stemming from inductive sets to be applied in unstructured
   853     scripts, while still benefitting from proper handling of non-atomic
   854     statements; NB: major inductive premises need to be put first, all
   855     the rest of the goal is passed through the induction;
   856   - 'induct' proper support for mutual induction involving non-atomic
   857     rule statements (uses the new concept of simultaneous goals, see
   858     below);
   859   - append all possible rule selections, but only use the first
   860     success (no backtracking);
   861   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   862   - undeclared rule case names default to numbers 1, 2, 3, ...;
   863   - added 'print_induct_rules' (covered by help item in recent Proof
   864     General versions);
   865   - moved induct/cases attributes to Pure, methods to Provers;
   866   - generic method setup instantiated for FOL and HOL;
   867 
   868 * Pure: support multiple simultaneous goal statements, for example
   869 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   870 meta-level mechanism, this acts as if several individual goals had
   871 been stated separately; in particular common proof methods need to be
   872 repeated in order to cover all claims; note that a single elimination
   873 step is *not* sufficient to establish the two conjunctions, so this
   874 fails:
   875 
   876   assume "A & B" then have A and B ..   (*".." fails*)
   877 
   878 better use "obtain" in situations as above; alternative refer to
   879 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   880 
   881 * Pure: proper integration with ``locales''; unlike the original
   882 version by Florian Kammller, Isar locales package high-level proof
   883 contexts rather than raw logical ones (e.g. we admit to include
   884 attributes everywhere); operations on locales include merge and
   885 rename; support for implicit arguments (``structures''); simultaneous
   886 type-inference over imports and text; see also HOL/ex/Locales.thy for
   887 some examples;
   888 
   889 * Pure: the following commands have been ``localized'', supporting a
   890 target locale specification "(in name)": 'lemma', 'theorem',
   891 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   892 stored both within the locale and at the theory level (exported and
   893 qualified by the locale name);
   894 
   895 * Pure: theory goals may now be specified in ``long'' form, with
   896 ad-hoc contexts consisting of arbitrary locale elements. for example
   897 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   898 definitions may be given, too); the result is a meta-level rule with
   899 the context elements being discharged in the obvious way;
   900 
   901 * Pure: new proof command 'using' allows to augment currently used
   902 facts after a goal statement ('using' is syntactically analogous to
   903 'apply', but acts on the goal's facts only); this allows chained facts
   904 to be separated into parts given before and after a claim, as in
   905 ``from a and b have C using d and e <proof>'';
   906 
   907 * Pure: renamed "antecedent" case to "rule_context";
   908 
   909 * Pure: new 'judgment' command records explicit information about the
   910 object-logic embedding (used by several tools internally); no longer
   911 use hard-wired "Trueprop";
   912 
   913 * Pure: added 'corollary' command;
   914 
   915 * Pure: fixed 'token_translation' command;
   916 
   917 * Pure: removed obsolete 'exported' attribute;
   918 
   919 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   920 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   921 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   922 
   923 * Pure: method 'atomize' presents local goal premises as object-level
   924 statements (atomic meta-level propositions); setup controlled via
   925 rewrite rules declarations of 'atomize' attribute; example
   926 application: 'induct' method with proper rule statements in improper
   927 proof *scripts*;
   928 
   929 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   930 now consider the syntactic context of assumptions, giving a better
   931 chance to get type-inference of the arguments right (this is
   932 especially important for locales);
   933 
   934 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   935 mode;
   936 
   937 * Pure/obtain: the formal conclusion "thesis", being marked as
   938 ``internal'', may no longer be reference directly in the text;
   939 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   940 situations;
   941 
   942 * Pure: generic 'sym' attribute which declares a rule both as pure
   943 'elim?' and for the 'symmetric' operation;
   944 
   945 * Pure: marginal comments ``--'' may now occur just anywhere in the
   946 text; the fixed correlation with particular command syntax has been
   947 discontinued;
   948 
   949 * Pure: new method 'rules' is particularly well-suited for proof
   950 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   951 but often produces more compact proof terms with less detours;
   952 
   953 * Pure/Provers/classical: simplified integration with pure rule
   954 attributes and methods; the classical "intro?/elim?/dest?"
   955 declarations coincide with the pure ones; the "rule" method no longer
   956 includes classically swapped intros; "intro" and "elim" methods no
   957 longer pick rules from the context; also got rid of ML declarations
   958 AddXIs/AddXEs/AddXDs; all of this has some potential for
   959 INCOMPATIBILITY;
   960 
   961 * Provers/classical: attribute 'swapped' produces classical inversions
   962 of introduction rules;
   963 
   964 * Provers/simplifier: 'simplified' attribute may refer to explicit
   965 rules instead of full simplifier context; 'iff' attribute handles
   966 conditional rules;
   967 
   968 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   969 
   970 * HOL: 'recdef' now fails on unfinished automated proofs, use
   971 "(permissive)" option to recover old behavior;
   972 
   973 * HOL: 'inductive' no longer features separate (collective) attributes
   974 for 'intros' (was found too confusing);
   975 
   976 * HOL: properly declared induction rules less_induct and
   977 wf_induct_rule;
   978 
   979 
   980 *** HOL ***
   981 
   982 * HOL: moved over to sane numeral syntax; the new policy is as
   983 follows:
   984 
   985   - 0 and 1 are polymorphic constants, which are defined on any
   986   numeric type (nat, int, real etc.);
   987 
   988   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   989   binary representation internally;
   990 
   991   - type nat has special constructor Suc, and generally prefers Suc 0
   992   over 1::nat and Suc (Suc 0) over 2::nat;
   993 
   994 This change may cause significant problems of INCOMPATIBILITY; here
   995 are some hints on converting existing sources:
   996 
   997   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   998   entities, so expressions involving "-" (unary or binary minus) need
   999   to be spaced properly;
  1000 
  1001   - existing occurrences of "1" may need to be constraint "1::nat" or
  1002   even replaced by Suc 0; similar for old "2";
  1003 
  1004   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1005 
  1006   - remove all special provisions on numerals in proofs;
  1007 
  1008 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1009 representation (depends on bin_arith_simps in the default context);
  1010 
  1011 * HOL: symbolic syntax for x^2 (numeral 2);
  1012 
  1013 * HOL: the class of all HOL types is now called "type" rather than
  1014 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1015 in axclass/classes, instance/arities, and (usually rare) occurrences
  1016 in typings (of consts etc.); internally the class is called
  1017 "HOL.type", ML programs should refer to HOLogic.typeS;
  1018 
  1019 * HOL/record package improvements:
  1020   - new derived operations "fields" to build a partial record section,
  1021     "extend" to promote a fixed record to a record scheme, and
  1022     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1023     declared as simp by default;
  1024   - shared operations ("more", "fields", etc.) now need to be always
  1025     qualified) --- potential INCOMPATIBILITY;
  1026   - removed "make_scheme" operations (use "make" with "extend") --
  1027     INCOMPATIBILITY;
  1028   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1029   - provides cases/induct rules for use with corresponding Isar
  1030     methods (for concrete records, record schemes, concrete more
  1031     parts, and schematic more parts -- in that order);
  1032   - internal definitions directly based on a light-weight abstract
  1033     theory of product types over typedef rather than datatype;
  1034 
  1035 * HOL: generic code generator for generating executable ML code from
  1036 specifications; specific support for HOL constructs such as inductive
  1037 datatypes and sets, as well as recursive functions; can be invoked
  1038 via 'generate_code' theory section;
  1039 
  1040 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1041 
  1042 * HOL: consolidated and renamed several theories.  In particular:
  1043         Ord.thy has been absorbed into HOL.thy
  1044         String.thy has been absorbed into List.thy
  1045 
  1046 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1047 (beware of argument permutation!);
  1048 
  1049 * HOL: linorder_less_split superseded by linorder_cases;
  1050 
  1051 * HOL/List: "nodups" renamed to "distinct";
  1052 
  1053 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1054 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1055   - Ex_def has changed, now need to use some_eq_ex
  1056 
  1057 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1058 in this (rare) case use:
  1059 
  1060   delSWrapper "split_all_tac"
  1061   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1062 
  1063 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1064 MAY FAIL;
  1065 
  1066 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1067 Isabelle's type classes, ^ on functions and relations has too general
  1068 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1069 necessary to attach explicit type constraints;
  1070 
  1071 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1072 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1073 renamed accordingly (eg "compI" -> "rel_compI").
  1074 
  1075 * HOL: syntax translations now work properly with numerals and records
  1076 expressions;
  1077 
  1078 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1079 of "lam" -- INCOMPATIBILITY;
  1080 
  1081 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1082 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1083 renamed "Product_Type.unit";
  1084 
  1085 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1086 
  1087 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1088 the "cases" method);
  1089 
  1090 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1091 Florian Kammller);
  1092 
  1093 * HOL/IMP: updated and converted to new-style theory format; several
  1094 parts turned into readable document, with proper Isar proof texts and
  1095 some explanations (by Gerwin Klein);
  1096 
  1097 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1098 
  1099 * HOL-Hyperreal is now a logic image;
  1100 
  1101 
  1102 *** HOLCF ***
  1103 
  1104 * Isar: consts/constdefs supports mixfix syntax for continuous
  1105 operations;
  1106 
  1107 * Isar: domain package adapted to new-style theory format, e.g. see
  1108 HOLCF/ex/Dnat.thy;
  1109 
  1110 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1111 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1112 lift.induct_tac, always use UU instead of Undef;
  1113 
  1114 * HOLCF/IMP: updated and converted to new-style theory;
  1115 
  1116 
  1117 *** ZF ***
  1118 
  1119 * Isar: proper integration of logic-specific tools and packages,
  1120 including theory commands '(co)inductive', '(co)datatype',
  1121 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1122 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1123 
  1124 * theory Main no longer includes AC; for the Axiom of Choice, base
  1125 your theory on Main_ZFC;
  1126 
  1127 * the integer library now covers quotients and remainders, with many
  1128 laws relating division to addition, multiplication, etc.;
  1129 
  1130 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1131 typeless version of the formalism;
  1132 
  1133 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1134 format;
  1135 
  1136 * ZF/Induct: new directory for examples of inductive definitions,
  1137 including theory Multiset for multiset orderings; converted to
  1138 new-style theory format;
  1139 
  1140 * ZF: many new theorems about lists, ordinals, etc.;
  1141 
  1142 
  1143 *** General ***
  1144 
  1145 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1146 variable proof controls level of detail: 0 = no proofs (only oracle
  1147 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1148 also ref manual for further ML interfaces;
  1149 
  1150 * Pure/axclass: removed obsolete ML interface
  1151 goal_subclass/goal_arity;
  1152 
  1153 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1154 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1155 separate tokens, so expressions involving minus need to be spaced
  1156 properly;
  1157 
  1158 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1159 rather than "infixl" or "infixr";
  1160 
  1161 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1162 sort constraint specifications in type inference; e.g. "x::_::foo"
  1163 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1164 type variable);
  1165 
  1166 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1167 control output of nested => (types); the default behavior is
  1168 "type_brackets";
  1169 
  1170 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1171 tokens into AST constants;
  1172 
  1173 * Pure/syntax: prefer later declarations of translations and print
  1174 translation functions; potential INCOMPATIBILITY: need to reverse
  1175 multiple declarations for same syntax element constant;
  1176 
  1177 * Pure/show_hyps reset by default (in accordance to existing Isar
  1178 practice);
  1179 
  1180 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1181 addSafter;
  1182 
  1183 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1184 as well;
  1185 
  1186 * system: tested support for MacOS X; should be able to get Isabelle +
  1187 Proof General to work in a plain Terminal after installing Poly/ML
  1188 (e.g. from the Isabelle distribution area) and GNU bash alone
  1189 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1190 support requires further installations, e.g. from
  1191 http://fink.sourceforge.net/);
  1192 
  1193 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1194 
  1195 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1196 of 40 MB), cf. ML_OPTIONS;
  1197 
  1198 * system: Proof General keywords specification is now part of the
  1199 Isabelle distribution (see etc/isar-keywords.el);
  1200 
  1201 * system: support for persistent Proof General sessions (refrain from
  1202 outdating all loaded theories on startup); user may create writable
  1203 logic images like this: ``isabelle -q HOL Test'';
  1204 
  1205 * system: smart selection of Isabelle process versus Isabelle
  1206 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1207 run both "isabelle" and "Isabelle" even if file names are badly
  1208 damaged (executable inspects the case of the first letter of its own
  1209 name); added separate "isabelle-process" and "isabelle-interface";
  1210 
  1211 * system: refrain from any attempt at filtering input streams; no
  1212 longer support ``8bit'' encoding of old isabelle font, instead proper
  1213 iso-latin characters may now be used; the related isatools
  1214 "symbolinput" and "nonascii" have disappeared as well;
  1215 
  1216 * system: removed old "xterm" interface (the print modes "xterm" and
  1217 "xterm_color" are still available for direct use in a suitable
  1218 terminal);
  1219 
  1220 
  1221 
  1222 New in Isabelle99-2 (February 2001)
  1223 -----------------------------------
  1224 
  1225 *** Overview of INCOMPATIBILITIES ***
  1226 
  1227 * HOL: please note that theories in the Library and elsewhere often use the
  1228 new-style (Isar) format; to refer to their theorems in an ML script you must
  1229 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1230 
  1231 * HOL: inductive package no longer splits induction rule aggressively,
  1232 but only as far as specified by the introductions given; the old
  1233 format may be recovered via ML function complete_split_rule or attribute
  1234 'split_rule (complete)';
  1235 
  1236 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1237 gfp_Tarski to gfp_unfold;
  1238 
  1239 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1240 
  1241 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1242 relation); infix "^^" has been renamed "``"; infix "``" has been
  1243 renamed "`"; "univalent" has been renamed "single_valued";
  1244 
  1245 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1246 operation;
  1247 
  1248 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1249 
  1250 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1251 
  1252 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1253 consequence, it is no longer monotonic wrt. the local goal context
  1254 (which is now passed through the inductive cases);
  1255 
  1256 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1257 \<gg> to \<ggreater>;
  1258 
  1259 
  1260 *** Document preparation ***
  1261 
  1262 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1263 available: are "it" for near math-mode best-style output, "sl" for
  1264 slanted text style, and "tt" for plain type-writer; if no
  1265 \isabellestyle command is given, output is according to slanted
  1266 type-writer);
  1267 
  1268 * support sub/super scripts (for single symbols only), input syntax is
  1269 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1270 
  1271 * some more standard symbols; see Appendix A of the system manual for
  1272 the complete list of symbols defined in isabellesym.sty;
  1273 
  1274 * improved isabelle style files; more abstract symbol implementation
  1275 (should now use \isamath{...} and \isatext{...} in custom symbol
  1276 definitions);
  1277 
  1278 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1279 state; Note that presentation of goal states does not conform to
  1280 actual human-readable proof documents.  Please do not include goal
  1281 states into document output unless you really know what you are doing!
  1282 
  1283 * proper indentation of antiquoted output with proportional LaTeX
  1284 fonts;
  1285 
  1286 * no_document ML operator temporarily disables LaTeX document
  1287 generation;
  1288 
  1289 * isatool unsymbolize tunes sources for plain ASCII communication;
  1290 
  1291 
  1292 *** Isar ***
  1293 
  1294 * Pure: Isar now suffers initial goal statements to contain unbound
  1295 schematic variables (this does not conform to actual readable proof
  1296 documents, due to unpredictable outcome and non-compositional proof
  1297 checking); users who know what they are doing may use schematic goals
  1298 for Prolog-style synthesis of proven results;
  1299 
  1300 * Pure: assumption method (an implicit finishing) now handles actual
  1301 rules as well;
  1302 
  1303 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1304 initial goal, declare "that" only as Pure intro (only for single
  1305 steps); the "that" rule assumption may now be involved in implicit
  1306 finishing, thus ".." becomes a feasible for trivial obtains;
  1307 
  1308 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1309 instance proofs may be performed by "..";
  1310 
  1311 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1312 statements as well;
  1313 
  1314 * Pure: more robust selection of calculational rules;
  1315 
  1316 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1317 rule (as well as the assumption rule);
  1318 
  1319 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1320 lemmas, using the graph browser tool;
  1321 
  1322 * Pure: predict failure of "show" in interactive mode;
  1323 
  1324 * Pure: 'thms_containing' now takes actual terms as arguments;
  1325 
  1326 * HOL: improved method 'induct' --- now handles non-atomic goals
  1327 (potential INCOMPATIBILITY); tuned error handling;
  1328 
  1329 * HOL: cases and induct rules now provide explicit hints about the
  1330 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1331 any remaining facts are inserted into the goal verbatim;
  1332 
  1333 * HOL: local contexts (aka cases) may now contain term bindings as
  1334 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1335 the result to be shown in each case;
  1336 
  1337 * HOL: added 'recdef_tc' command;
  1338 
  1339 * isatool convert assists in eliminating legacy ML scripts;
  1340 
  1341 
  1342 *** HOL ***
  1343 
  1344 * HOL/Library: a collection of generic theories to be used together
  1345 with main HOL; the theory loader path already includes this directory
  1346 by default; the following existing theories have been moved here:
  1347 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1348 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1349 
  1350 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1351 modelling and verification task performed in Isabelle/HOL +
  1352 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1353 
  1354 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1355 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1356 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1357 'domain', this makes the theory consistent with mathematical
  1358 literature;
  1359 
  1360 * HOL basics: added overloaded operations "inverse" and "divide"
  1361 (infix "/"), syntax for generic "abs" operation, generic summation
  1362 operator \<Sum>;
  1363 
  1364 * HOL/typedef: simplified package, provide more useful rules (see also
  1365 HOL/subset.thy);
  1366 
  1367 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1368 now expressed as a proper nested rule (old-style tactic scripts may
  1369 require atomize_strip_tac to cope with non-atomic premises);
  1370 
  1371 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1372 to "split_conv" (old name still available for compatibility);
  1373 
  1374 * HOL: improved concrete syntax for strings (e.g. allows translation
  1375 rules with string literals);
  1376 
  1377 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1378  and Fleuriot's mechanization of analysis, including the transcendental
  1379  functions for the reals;
  1380 
  1381 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1382 
  1383 
  1384 *** CTT ***
  1385 
  1386 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1387 "lam" is displayed as TWO lambda-symbols
  1388 
  1389 * CTT: theory Main now available, containing everything (that is, Bool
  1390 and Arith);
  1391 
  1392 
  1393 *** General ***
  1394 
  1395 * Pure: the Simplifier has been implemented properly as a derived rule
  1396 outside of the actual kernel (at last!); the overall performance
  1397 penalty in practical applications is about 50%, while reliability of
  1398 the Isabelle inference kernel has been greatly improved;
  1399 
  1400 * print modes "brackets" and "no_brackets" control output of nested =>
  1401 (types) and ==> (props); the default behaviour is "brackets";
  1402 
  1403 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1404 as assumptions as well;
  1405 
  1406 * system: support Poly/ML 4.0;
  1407 
  1408 * system: isatool install handles KDE version 1 or 2;
  1409 
  1410 
  1411 
  1412 New in Isabelle99-1 (October 2000)
  1413 ----------------------------------
  1414 
  1415 *** Overview of INCOMPATIBILITIES ***
  1416 
  1417 * HOL: simplification of natural numbers is much changed; to partly
  1418 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1419 issue the following ML commands:
  1420 
  1421   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1422   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1423 
  1424 * HOL: simplification no longer dives into case-expressions; this is
  1425 controlled by "t.weak_case_cong" for each datatype t;
  1426 
  1427 * HOL: nat_less_induct renamed to less_induct;
  1428 
  1429 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1430 fixsome to patch .thy and .ML sources automatically;
  1431 
  1432   select_equality  -> some_equality
  1433   select_eq_Ex     -> some_eq_ex
  1434   selectI2EX       -> someI2_ex
  1435   selectI2         -> someI2
  1436   selectI          -> someI
  1437   select1_equality -> some1_equality
  1438   Eps_sym_eq       -> some_sym_eq_trivial
  1439   Eps_eq           -> some_eq_trivial
  1440 
  1441 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1442 
  1443 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1444 instead);
  1445 
  1446 * HOL: the recursion equations generated by 'recdef' are now called
  1447 f.simps instead of f.rules;
  1448 
  1449 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1450 
  1451 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1452 sometimes be needed;
  1453 
  1454 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1455 
  1456 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1457 
  1458 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1459 product is now "<*>" instead of "Times"; the lexicographic product is
  1460 now "<*lex*>" instead of "**";
  1461 
  1462 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1463 of main HOL, but was unused); better use HOL's datatype package;
  1464 
  1465 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1466 the old syntax may be recovered as follows:
  1467 
  1468   syntax (symbols)
  1469     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1470       (infixl "\\<oplus>" 100)
  1471 
  1472 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1473 
  1474 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1475 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1476 internally;
  1477 
  1478 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1479 changed from A/r to A//r;
  1480 
  1481 * ZF: new treatment of arithmetic (nat & int) may break some old
  1482 proofs;
  1483 
  1484 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1485 rulify -> rule_format, elimify -> elim_format, ...);
  1486 
  1487 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1488 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1489 should have to change intro!! to intro? only); replaced "delrule" by
  1490 "rule del";
  1491 
  1492 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1493 
  1494 * Provers: strengthened force_tac by using new first_best_tac;
  1495 
  1496 * LaTeX document preparation: several changes of isabelle.sty (see
  1497 lib/texinputs);
  1498 
  1499 
  1500 *** Document preparation ***
  1501 
  1502 * formal comments (text blocks etc.) in new-style theories may now
  1503 contain antiquotations of thm/prop/term/typ/text to be presented
  1504 according to latex print mode; concrete syntax is like this:
  1505 @{term[show_types] "f(x) = a + x"};
  1506 
  1507 * isatool mkdir provides easy setup of Isabelle session directories,
  1508 including proper document sources;
  1509 
  1510 * generated LaTeX sources are now deleted after successful run
  1511 (isatool document -c); may retain a copy somewhere else via -D option
  1512 of isatool usedir;
  1513 
  1514 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1515 style files, achieving self-contained LaTeX sources and simplifying
  1516 LaTeX debugging;
  1517 
  1518 * old-style theories now produce (crude) LaTeX output as well;
  1519 
  1520 * browser info session directories are now self-contained (may be put
  1521 on WWW server seperately); improved graphs of nested sessions; removed
  1522 graph for 'all sessions';
  1523 
  1524 * several improvements in isabelle style files; \isabellestyle{it}
  1525 produces fake math mode output; \isamarkupheader is now \section by
  1526 default; see lib/texinputs/isabelle.sty etc.;
  1527 
  1528 
  1529 *** Isar ***
  1530 
  1531 * Isar/Pure: local results and corresponding term bindings are now
  1532 subject to Hindley-Milner polymorphism (similar to ML); this
  1533 accommodates incremental type-inference very nicely;
  1534 
  1535 * Isar/Pure: new derived language element 'obtain' supports
  1536 generalized existence reasoning;
  1537 
  1538 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1539 support accumulation of results, without applying any rules yet;
  1540 useful to collect intermediate results without explicit name
  1541 references, and for use with transitivity rules with more than 2
  1542 premises;
  1543 
  1544 * Isar/Pure: scalable support for case-analysis type proofs: new
  1545 'case' language element refers to local contexts symbolically, as
  1546 produced by certain proof methods; internally, case names are attached
  1547 to theorems as "tags";
  1548 
  1549 * Isar/Pure: theory command 'hide' removes declarations from
  1550 class/type/const name spaces;
  1551 
  1552 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1553 indicate potential overloading;
  1554 
  1555 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1556 
  1557 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1558 "{a,b,c}" instead of {a,b,c};
  1559 
  1560 * Isar/Pure now provides its own version of intro/elim/dest
  1561 attributes; useful for building new logics, but beware of confusion
  1562 with the version in Provers/classical;
  1563 
  1564 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1565 case name 'antecedent';
  1566 
  1567 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1568 to the current context is now done automatically);
  1569 
  1570 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1571 for definining proof methods in ML;
  1572 
  1573 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1574 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1575 most cases, one should have to change intro!! to intro? only);
  1576 replaced "delrule" by "rule del";
  1577 
  1578 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1579 'symmetric' attribute (the latter supercedes [RS sym]);
  1580 
  1581 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1582 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1583 well (including splits);
  1584 
  1585 * Isar/Provers: Simplifier and Classical methods now support all kind
  1586 of modifiers used in the past, including 'cong', 'iff', etc.
  1587 
  1588 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1589 of Simplifier and Classical reasoner);
  1590 
  1591 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1592 now support named cases; major packages (inductive, datatype, primrec,
  1593 recdef) support case names and properly name parameters;
  1594 
  1595 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1596 monotonicity conditions are extracted to be proven at end of
  1597 calculations;
  1598 
  1599 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1600 method anyway;
  1601 
  1602 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1603 split_if split_if_asm; datatype package provides theorems foo.splits =
  1604 foo.split foo.split_asm for each datatype;
  1605 
  1606 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1607 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1608 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1609 use "(cases (simplified))" method in proper proof texts);
  1610 
  1611 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1612 
  1613 * Isar: names of theorems etc. may be natural numbers as well;
  1614 
  1615 * Isar: 'pr' command: optional arguments for goals_limit and
  1616 ProofContext.prems_limit; no longer prints theory contexts, but only
  1617 proof states;
  1618 
  1619 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1620 additional print modes to be specified; e.g. "pr(latex)" will print
  1621 proof state according to the Isabelle LaTeX style;
  1622 
  1623 * Isar: improved support for emulating tactic scripts, including proof
  1624 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1625 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1626 (for HOL datatypes);
  1627 
  1628 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1629 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1630 'proof method scripts' have to be in depth-first order;
  1631 
  1632 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1633 
  1634 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1635 should instead use individual commands for printing items
  1636 (print_commands, print_methods etc.);
  1637 
  1638 * Isar: added 'nothing' --- the empty list of theorems;
  1639 
  1640 
  1641 *** HOL ***
  1642 
  1643 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1644 corresponding virtual machine and a specification of its bytecode
  1645 verifier and a lightweight bytecode verifier, including proofs of
  1646 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1647 Cornelia Pusch (see also the homepage of project Bali at
  1648 http://isabelle.in.tum.de/Bali/);
  1649 
  1650 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1651 Clemens Ballarin;
  1652 
  1653 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1654 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1655 Rasmussen;
  1656 
  1657 * HOL/Lattice: fundamental concepts of lattice theory and order
  1658 structures, including duals, properties of bounds versus algebraic
  1659 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1660 Theorem for complete lattices etc.; may also serve as a demonstration
  1661 for abstract algebraic reasoning using axiomatic type classes, and
  1662 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1663 
  1664 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1665 von Oheimb;
  1666 
  1667 * HOL/IMPP: extension of IMP with local variables and mutually
  1668 recursive procedures, by David von Oheimb;
  1669 
  1670 * HOL/Lambda: converted into new-style theory and document;
  1671 
  1672 * HOL/ex/Multiquote: example of multiple nested quotations and
  1673 anti-quotations -- basically a generalized version of de-Bruijn
  1674 representation; very useful in avoiding lifting of operations;
  1675 
  1676 * HOL/record: added general record equality rule to simpset; fixed
  1677 select-update simplification procedure to handle extended records as
  1678 well; admit "r" as field name;
  1679 
  1680 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1681 other numeric types and also as the identity of groups, rings, etc.;
  1682 
  1683 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1684 Types nat and int belong to this axclass;
  1685 
  1686 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1687    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1688    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1689   two terms #m*u and #n*u are replaced by #(m+n)*u
  1690     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1691   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1692     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1693 
  1694 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1695 powerful prover for predicate logic but knows nothing of clasets; see
  1696 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1697 
  1698 * HOL: new version of "case_tac" subsumes both boolean case split and
  1699 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1700 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1701 
  1702 * HOL: simplification no longer dives into case-expressions: only the
  1703 selector expression is simplified, but not the remaining arms; to
  1704 enable full simplification of case-expressions for datatype t, you may
  1705 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1706 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1707 
  1708 * HOL/recdef: the recursion equations generated by 'recdef' for
  1709 function 'f' are now called f.simps instead of f.rules; if all
  1710 termination conditions are proved automatically, these simplification
  1711 rules are added to the simpset, as in primrec; rules may be named
  1712 individually as well, resulting in a separate list of theorems for
  1713 each equation;
  1714 
  1715 * HOL/While is a new theory that provides a while-combinator. It
  1716 permits the definition of tail-recursive functions without the
  1717 provision of a termination measure. The latter is necessary once the
  1718 invariant proof rule for while is applied.
  1719 
  1720 * HOL: new (overloaded) notation for the set of elements below/above
  1721 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1722 
  1723 * HOL: theorems impI, allI, ballI bound as "strip";
  1724 
  1725 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1726 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1727 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1728 
  1729 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1730 
  1731 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1732 main HOL, but was unused);
  1733 
  1734 * HOL: fewer consts declared as global (e.g. have to refer to
  1735 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1736 
  1737 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1738 in case of overlap with user translations (e.g. judgements over
  1739 tuples); (note that the underlying logical represenation is still
  1740 bogus);
  1741 
  1742 
  1743 *** ZF ***
  1744 
  1745 * ZF: simplification automatically cancels common terms in arithmetic
  1746 expressions over nat and int;
  1747 
  1748 * ZF: new treatment of nat to minimize type-checking: all operators
  1749 coerce their operands to a natural number using the function natify,
  1750 making the algebraic laws unconditional;
  1751 
  1752 * ZF: as above, for int: operators coerce their operands to an integer
  1753 using the function intify;
  1754 
  1755 * ZF: the integer library now contains many of the usual laws for the
  1756 orderings, including $<=, and monotonicity laws for $+ and $*;
  1757 
  1758 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1759 simplification;
  1760 
  1761 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1762 to the simplifier and classical reasoner simultaneously;
  1763 
  1764 
  1765 *** General ***
  1766 
  1767 * Provers: blast_tac now handles actual object-logic rules as
  1768 assumptions; note that auto_tac uses blast_tac internally as well;
  1769 
  1770 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1771 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1772 
  1773 * Provers: delrules now handles destruct rules as well (no longer need
  1774 explicit make_elim);
  1775 
  1776 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1777   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1778 use instead the strong form,
  1779   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1780 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1781 from destruct-rules;
  1782 
  1783 * Provers: Simplifier.easy_setup provides a fast path to basic
  1784 Simplifier setup for new object-logics;
  1785 
  1786 * Pure: AST translation rules no longer require constant head on LHS;
  1787 
  1788 * Pure: improved name spaces: ambiguous output is qualified; support
  1789 for hiding of names;
  1790 
  1791 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1792 XSYMBOL_HOME; no longer need to do manual configuration in most
  1793 situations;
  1794 
  1795 * system: compression of ML heaps images may now be controlled via -c
  1796 option of isabelle and isatool usedir (currently only observed by
  1797 Poly/ML);
  1798 
  1799 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1800 useful for remote X11);
  1801 
  1802 * system: provide TAGS file for Isabelle sources;
  1803 
  1804 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1805 order;
  1806 
  1807 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1808 timing flag supersedes proof_timing and Toplevel.trace;
  1809 
  1810 * ML: new combinators |>> and |>>> for incremental transformations
  1811 with secondary results (e.g. certain theory extensions):
  1812 
  1813 * ML: PureThy.add_defs gets additional argument to indicate potential
  1814 overloading (usually false);
  1815 
  1816 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1817 results;
  1818 
  1819 
  1820 
  1821 New in Isabelle99 (October 1999)
  1822 --------------------------------
  1823 
  1824 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1825 
  1826 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1827 are no longer simplified.  (This allows the simplifier to unfold recursive
  1828 functional programs.)  To restore the old behaviour, declare
  1829 
  1830     Delcongs [if_weak_cong];
  1831 
  1832 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1833 complement;
  1834 
  1835 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1836 
  1837 * HOL/datatype: mutual_induct_tac no longer exists --
  1838   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1839 
  1840 * HOL/typedef: fixed type inference for representing set; type
  1841 arguments now have to occur explicitly on the rhs as type constraints;
  1842 
  1843 * ZF: The con_defs part of an inductive definition may no longer refer
  1844 to constants declared in the same theory;
  1845 
  1846 * HOL, ZF: the function mk_cases, generated by the inductive
  1847 definition package, has lost an argument.  To simplify its result, it
  1848 uses the default simpset instead of a supplied list of theorems.
  1849 
  1850 * HOL/List: the constructors of type list are now Nil and Cons;
  1851 
  1852 * Simplifier: the type of the infix ML functions
  1853         setSSolver addSSolver setSolver addSolver
  1854 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1855 for packaging solvers. A solver is created via
  1856         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1857 where the string argument is only a comment.
  1858 
  1859 
  1860 *** Proof tools ***
  1861 
  1862 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1863 decision procedure for linear arithmetic. Currently it is used for
  1864 types `nat', `int', and `real' in HOL (see below); it can, should and
  1865 will be instantiated for other types and logics as well.
  1866 
  1867 * The simplifier now accepts rewrite rules with flexible heads, eg
  1868      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1869   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1870   matching.
  1871 
  1872 
  1873 *** General ***
  1874 
  1875 * New Isabelle/Isar subsystem provides an alternative to traditional
  1876 tactical theorem proving; together with the ProofGeneral/isar user
  1877 interface it offers an interactive environment for developing human
  1878 readable proof documents (Isar == Intelligible semi-automated
  1879 reasoning); for further information see isatool doc isar-ref,
  1880 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1881 
  1882 * improved and simplified presentation of theories: better HTML markup
  1883 (including colors), graph views in several sizes; isatool usedir now
  1884 provides a proper interface for user theories (via -P option); actual
  1885 document preparation based on (PDF)LaTeX is available as well (for
  1886 new-style theories only); see isatool doc system for more information;
  1887 
  1888 * native support for Proof General, both for classic Isabelle and
  1889 Isabelle/Isar;
  1890 
  1891 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1892 using the graph browser tool;
  1893 
  1894 * Isabelle manuals now also available as PDF;
  1895 
  1896 * theory loader rewritten from scratch (may not be fully
  1897 bug-compatible); old loadpath variable has been replaced by show_path,
  1898 add_path, del_path, reset_path functions; new operations such as
  1899 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1900 isatool doc ref);
  1901 
  1902 * improved isatool install: option -k creates KDE application icon,
  1903 option -p DIR installs standalone binaries;
  1904 
  1905 * added ML_PLATFORM setting (useful for cross-platform installations);
  1906 more robust handling of platform specific ML images for SML/NJ;
  1907 
  1908 * the settings environment is now statically scoped, i.e. it is never
  1909 created again in sub-processes invoked from isabelle, isatool, or
  1910 Isabelle;
  1911 
  1912 * path element specification '~~' refers to '$ISABELLE_HOME';
  1913 
  1914 * in locales, the "assumes" and "defines" parts may be omitted if
  1915 empty;
  1916 
  1917 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1918 long arrows);
  1919 
  1920 * new print_mode "HTML";
  1921 
  1922 * new flag show_tags controls display of tags of theorems (which are
  1923 basically just comments that may be attached by some tools);
  1924 
  1925 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1926 mode and goal output format:
  1927 
  1928 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1929 244c244
  1930 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1931 ---
  1932 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1933 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1934 181c181
  1935 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1936 ---
  1937 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1938 
  1939 * function bind_thms stores lists of theorems (cf. bind_thm);
  1940 
  1941 * new shorthand tactics ftac, eatac, datac, fatac;
  1942 
  1943 * qed (and friends) now accept "" as result name; in that case the
  1944 theorem is not stored, but proper checks and presentation of the
  1945 result still apply;
  1946 
  1947 * theorem database now also indexes constants "Trueprop", "all",
  1948 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1949 
  1950 
  1951 *** HOL ***
  1952 
  1953 ** HOL arithmetic **
  1954 
  1955 * There are now decision procedures for linear arithmetic over nat and
  1956 int:
  1957 
  1958 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1959 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1960 are treated as atomic; subformulae not involving type `nat' or `int'
  1961 are ignored; quantified subformulae are ignored unless they are
  1962 positive universal or negative existential. The tactic has to be
  1963 invoked by hand and can be a little bit slow. In particular, the
  1964 running time is exponential in the number of occurrences of `min' and
  1965 `max', and `-' on `nat'.
  1966 
  1967 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1968 (negated) (in)equalities among the premises and the conclusion into
  1969 account (i.e. no compound formulae) and does not know about `min' and
  1970 `max', and `-' on `nat'. It is fast and is used automatically by the
  1971 simplifier.
  1972 
  1973 NB: At the moment, these decision procedures do not cope with mixed
  1974 nat/int formulae where the two parts interact, such as `m < n ==>
  1975 int(m) < int(n)'.
  1976 
  1977 * HOL/Numeral provides a generic theory of numerals (encoded
  1978 efficiently as bit strings); setup for types nat/int/real is in place;
  1979 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1980 int, existing theories and proof scripts may require a few additional
  1981 type constraints;
  1982 
  1983 * integer division and remainder can now be performed on constant
  1984 arguments;
  1985 
  1986 * many properties of integer multiplication, division and remainder
  1987 are now available;
  1988 
  1989 * An interface to the Stanford Validity Checker (SVC) is available through the
  1990 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1991 are proved automatically.  SVC must be installed separately, and its results
  1992 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1993 invocation of the underlying oracle).  For SVC see
  1994   http://verify.stanford.edu/SVC
  1995 
  1996 * IsaMakefile: the HOL-Real target now builds an actual image;
  1997 
  1998 
  1999 ** HOL misc **
  2000 
  2001 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2002 (in Isabelle/Isar) -- by Gertrud Bauer;
  2003 
  2004 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2005 analysis for assembly languages with subtypes;
  2006 
  2007 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2008 -- avoids syntactic ambiguities and treats state, transition, and
  2009 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2010 changed syntax and (many) tactics;
  2011 
  2012 * HOL/inductive: Now also handles more general introduction rules such
  2013   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2014   theorems are now maintained within the theory (maintained via the
  2015   "mono" attribute);
  2016 
  2017 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2018   (using function types) such as
  2019 
  2020   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2021 
  2022 * HOL/record: record_simproc (part of the default simpset) takes care
  2023 of selectors applied to updated records; record_split_tac is no longer
  2024 part of the default claset; update_defs may now be removed from the
  2025 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2026 
  2027   claset_ref () := claset() addSWrapper record_split_wrapper;
  2028   Delsimprocs [record_simproc]
  2029 
  2030 * HOL/typedef: fixed type inference for representing set; type
  2031 arguments now have to occur explicitly on the rhs as type constraints;
  2032 
  2033 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2034 names rather than an ML expression;
  2035 
  2036 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2037 supplied later.  Program schemes can be defined, such as
  2038     "While B C s = (if B s then While B C (C s) else s)"
  2039 where the well-founded relation can be chosen after B and C have been given.
  2040 
  2041 * HOL/List: the constructors of type list are now Nil and Cons;
  2042 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2043 course, ML tools referring to List.list.op # etc. have to be adapted;
  2044 
  2045 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2046 disabled by default; run isabelle with option -m HOL to get back to
  2047 the original Gordon/HOL-style output;
  2048 
  2049 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2050 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2051 
  2052 * HOL basic syntax simplified (more orthogonal): all variants of
  2053 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2054 Eps operator is provided as well: "SOME x. P[x]";
  2055 
  2056 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2057 
  2058 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2059 thus available for user theories;
  2060 
  2061 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2062 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2063 time;
  2064 
  2065 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2066 several times and then mp;
  2067 
  2068 
  2069 *** LK ***
  2070 
  2071 * the notation <<...>> is now available as a notation for sequences of
  2072 formulas;
  2073 
  2074 * the simplifier is now installed
  2075 
  2076 * the axiom system has been generalized (thanks to Soren Heilmann)
  2077 
  2078 * the classical reasoner now has a default rule database
  2079 
  2080 
  2081 *** ZF ***
  2082 
  2083 * new primrec section allows primitive recursive functions to be given
  2084 directly (as in HOL) over datatypes and the natural numbers;
  2085 
  2086 * new tactics induct_tac and exhaust_tac for induction (or case
  2087 analysis) over datatypes and the natural numbers;
  2088 
  2089 * the datatype declaration of type T now defines the recursor T_rec;
  2090 
  2091 * simplification automatically does freeness reasoning for datatype
  2092 constructors;
  2093 
  2094 * automatic type-inference, with AddTCs command to insert new
  2095 type-checking rules;
  2096 
  2097 * datatype introduction rules are now added as Safe Introduction rules
  2098 to the claset;
  2099 
  2100 * the syntax "if P then x else y" is now available in addition to
  2101 if(P,x,y);
  2102 
  2103 
  2104 *** Internal programming interfaces ***
  2105 
  2106 * tuned simplifier trace output; new flag debug_simp;
  2107 
  2108 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2109 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2110 
  2111 * AxClass.axclass_tac lost the theory argument;
  2112 
  2113 * tuned current_goals_markers semantics: begin / end goal avoids
  2114 printing empty lines;
  2115 
  2116 * removed prs and prs_fn hook, which was broken because it did not
  2117 include \n in its semantics, forcing writeln to add one
  2118 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2119 string -> unit if you really want to output text without newline;
  2120 
  2121 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2122 plain output, interface builders may have to enable 'isabelle_font'
  2123 mode to get Isabelle font glyphs as before;
  2124 
  2125 * refined token_translation interface; INCOMPATIBILITY: output length
  2126 now of type real instead of int;
  2127 
  2128 * theory loader actions may be traced via new ThyInfo.add_hook
  2129 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2130 your own database of information attached to *whole* theories -- as
  2131 opposed to intra-theory data slots offered via TheoryDataFun;
  2132 
  2133 * proper handling of dangling sort hypotheses (at last!);
  2134 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2135 extra sort hypotheses that can be witnessed from the type signature;
  2136 the force_strip_shyps flag is gone, any remaining shyps are simply
  2137 left in the theorem (with a warning issued by strip_shyps_warning);
  2138 
  2139 
  2140 
  2141 New in Isabelle98-1 (October 1998)
  2142 ----------------------------------
  2143 
  2144 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2145 
  2146 * several changes of automated proof tools;
  2147 
  2148 * HOL: major changes to the inductive and datatype packages, including
  2149 some minor incompatibilities of theory syntax;
  2150 
  2151 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2152 called `inj_on';
  2153 
  2154 * HOL: removed duplicate thms in Arith:
  2155   less_imp_add_less  should be replaced by  trans_less_add1
  2156   le_imp_add_le      should be replaced by  trans_le_add1
  2157 
  2158 * HOL: unary minus is now overloaded (new type constraints may be
  2159 required);
  2160 
  2161 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2162 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2163 now taken as an integer constant.
  2164 
  2165 * Pure: ML function 'theory_of' renamed to 'theory';
  2166 
  2167 
  2168 *** Proof tools ***
  2169 
  2170 * Simplifier:
  2171   1. Asm_full_simp_tac is now more aggressive.
  2172      1. It will sometimes reorient premises if that increases their power to
  2173         simplify.
  2174      2. It does no longer proceed strictly from left to right but may also
  2175         rotate premises to achieve further simplification.
  2176      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2177      old Asm_full_simp_tac in that it does not rotate premises.
  2178   2. The simplifier now knows a little bit about nat-arithmetic.
  2179 
  2180 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2181 allows for selected deletion of wrappers, by introduction of names for
  2182 wrapper functionals.  This implies that addbefore, addSbefore,
  2183 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2184 and that adding two tactics with the same name overwrites the first
  2185 one (emitting a warning).
  2186   type wrapper = (int -> tactic) -> (int -> tactic)
  2187   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2188   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2189   delWrapper, delSWrapper: claset *  string            -> claset
  2190   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2191 
  2192 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2193 semantics; addbefore now affects only the unsafe part of step_tac
  2194 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2195 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2196 by Force_tac;
  2197 
  2198 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2199 compWrapper; added safe wrapper (and access functions for it);
  2200 
  2201 * HOL/split_all_tac is now much faster and fails if there is nothing
  2202 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2203 and the names of the automatically generated variables have changed.
  2204 split_all_tac has moved within claset() from unsafe wrappers to safe
  2205 wrappers, which means that !!-bound variables are split much more
  2206 aggressively, and safe_tac and clarify_tac now split such variables.
  2207 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2208 Note: the same holds for record_split_tac, which does the job of
  2209 split_all_tac for record fields.
  2210 
  2211 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2212 permanently to the default simpset using Addsplits just like
  2213 Addsimps. They can be removed via Delsplits just like
  2214 Delsimps. Lower-case versions are also available.
  2215 
  2216 * HOL/Simplifier: The rule split_if is now part of the default
  2217 simpset. This means that the simplifier will eliminate all occurrences
  2218 of if-then-else in the conclusion of a goal. To prevent this, you can
  2219 either remove split_if completely from the default simpset by
  2220 `Delsplits [split_if]' or remove it in a specific call of the
  2221 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2222 other case splitting rules to/from the default simpset: every datatype
  2223 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2224 t is the name of the datatype).
  2225 
  2226 * Classical reasoner / Simplifier combination: new force_tac (and
  2227 derivatives Force_tac, force) combines rewriting and classical
  2228 reasoning (and whatever other tools) similarly to auto_tac, but is
  2229 aimed to solve the given subgoal completely.
  2230 
  2231 
  2232 *** General ***
  2233 
  2234 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2235 and `goalw': the theory is no longer needed as an explicit argument -
  2236 the current theory context is used; assumptions are no longer returned
  2237 at the ML-level unless one of them starts with ==> or !!; it is
  2238 recommended to convert to these new commands using isatool fixgoal
  2239 (backup your sources first!);
  2240 
  2241 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2242 the current theory context, and 'theory' to lookup stored theories;
  2243 
  2244 * new theory section 'locale' for declaring constants, assumptions and
  2245 definitions that have local scope;
  2246 
  2247 * new theory section 'nonterminals' for purely syntactic types;
  2248 
  2249 * new theory section 'setup' for generic ML setup functions
  2250 (e.g. package initialization);
  2251 
  2252 * the distribution now includes Isabelle icons: see
  2253 lib/logo/isabelle-{small,tiny}.xpm;
  2254 
  2255 * isatool install - install binaries with absolute references to
  2256 ISABELLE_HOME/bin;
  2257 
  2258 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2259 
  2260 * print mode 'emacs' reserved for Isamode;
  2261 
  2262 * support multiple print (ast) translations per constant name;
  2263 
  2264 * theorems involving oracles are now printed with a suffixed [!];
  2265 
  2266 
  2267 *** HOL ***
  2268 
  2269 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2270 
  2271 * HOL/inductive package reorganized and improved: now supports mutual
  2272 definitions such as
  2273 
  2274   inductive EVEN ODD
  2275     intrs
  2276       null "0 : EVEN"
  2277       oddI "n : EVEN ==> Suc n : ODD"
  2278       evenI "n : ODD ==> Suc n : EVEN"
  2279 
  2280 new theorem list "elims" contains an elimination rule for each of the
  2281 recursive sets; inductive definitions now handle disjunctive premises
  2282 correctly (also ZF);
  2283 
  2284 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2285 "mutual_induct" no longer exists - the induction rule is always
  2286 contained in "induct";
  2287 
  2288 
  2289 * HOL/datatype package re-implemented and greatly improved: now
  2290 supports mutually recursive datatypes such as
  2291 
  2292   datatype
  2293     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2294             | SUM ('a aexp) ('a aexp)
  2295             | DIFF ('a aexp) ('a aexp)
  2296             | NUM 'a
  2297   and
  2298     'a bexp = LESS ('a aexp) ('a aexp)
  2299             | AND ('a bexp) ('a bexp)
  2300             | OR ('a bexp) ('a bexp)
  2301 
  2302 as well as indirectly recursive datatypes such as
  2303 
  2304   datatype
  2305     ('a, 'b) term = Var 'a
  2306                   | App 'b ((('a, 'b) term) list)
  2307 
  2308 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2309 induction on mutually / indirectly recursive datatypes.
  2310 
  2311 Primrec equations are now stored in theory and can be accessed via
  2312 <function_name>.simps.
  2313 
  2314 INCOMPATIBILITIES:
  2315 
  2316   - Theories using datatypes must now have theory Datatype as an
  2317     ancestor.
  2318   - The specific <typename>.induct_tac no longer exists - use the
  2319     generic induct_tac instead.
  2320   - natE has been renamed to nat.exhaust - use exhaust_tac
  2321     instead of res_inst_tac ... natE. Note that the variable
  2322     names in nat.exhaust differ from the names in natE, this
  2323     may cause some "fragile" proofs to fail.
  2324   - The theorems split_<typename>_case and split_<typename>_case_asm
  2325     have been renamed to <typename>.split and <typename>.split_asm.
  2326   - Since default sorts of type variables are now handled correctly,
  2327     some datatype definitions may have to be annotated with explicit
  2328     sort constraints.
  2329   - Primrec definitions no longer require function name and type
  2330     of recursive argument.
  2331 
  2332 Consider using isatool fixdatatype to adapt your theories and proof
  2333 scripts to the new package (backup your sources first!).
  2334 
  2335 
  2336 * HOL/record package: considerably improved implementation; now
  2337 includes concrete syntax for record types, terms, updates; theorems
  2338 for surjective pairing and splitting !!-bound record variables; proof
  2339 support is as follows:
  2340 
  2341   1) standard conversions (selectors or updates applied to record
  2342 constructor terms) are part of the standard simpset;
  2343 
  2344   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2345 made part of standard simpset and claset via addIffs;
  2346 
  2347   3) a tactic for record field splitting (record_split_tac) is part of
  2348 the standard claset (addSWrapper);
  2349 
  2350 To get a better idea about these rules you may retrieve them via
  2351 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2352 the name of your record type.
  2353 
  2354 The split tactic 3) conceptually simplifies by the following rule:
  2355 
  2356   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2357 
  2358 Thus any record variable that is bound by meta-all will automatically
  2359 blow up into some record constructor term, consequently the
  2360 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2361 solve record problems automatically.
  2362 
  2363 
  2364 * reorganized the main HOL image: HOL/Integ and String loaded by
  2365 default; theory Main includes everything;
  2366 
  2367 * automatic simplification of integer sums and comparisons, using cancellation;
  2368 
  2369 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2370 
  2371 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2372 
  2373 * many new identities for unions, intersections, set difference, etc.;
  2374 
  2375 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2376 called split_if, split_split, split_sum_case and split_nat_case (to go
  2377 with add/delsplits);
  2378 
  2379 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2380 (?x::unit) = (); this is made part of the default simpset, which COULD
  2381 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2382 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2383 unit_abs_eta_conv is added in order to counter the effect of
  2384 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2385 %u.f();
  2386 
  2387 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2388 makes more sense);
  2389 
  2390 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2391   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2392   disjointness reasoning but breaking a few old proofs.
  2393 
  2394 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2395 to 'converse' from 'inverse' (for compatibility with ZF and some
  2396 literature);
  2397 
  2398 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2399 the well-founded relation;
  2400 
  2401 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2402     Compl A.  The "Compl" syntax remains available as input syntax for this
  2403     release ONLY.
  2404 
  2405 * HOL/Update: new theory of function updates:
  2406     f(a:=b) == %x. if x=a then b else f x
  2407 may also be iterated as in f(a:=b,c:=d,...);
  2408 
  2409 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2410 
  2411 * HOL/List:
  2412   - new function list_update written xs[i:=v] that updates the i-th
  2413     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2414   - new function `upt' written [i..j(] which generates the list
  2415     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2416     bound write [i..j], which is a shorthand for [i..j+1(].
  2417   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2418 
  2419 * HOL/Arith:
  2420   - removed 'pred' (predecessor) function;
  2421   - generalized some theorems about n-1;
  2422   - many new laws about "div" and "mod";
  2423   - new laws about greatest common divisors (see theory ex/Primes);
  2424 
  2425 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2426 instead of "inverse";
  2427 
  2428 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2429   of the multiset ordering;
  2430 
  2431 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2432   (not included by default);
  2433 
  2434 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2435 
  2436 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2437   programs, i.e. different program variables may have different types.
  2438 
  2439 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2440   [previously, this check worked only if the rewrite rule was unconditional]
  2441   Now rew can involve either definitions or equalities (either == or =).
  2442 
  2443 
  2444 *** ZF ***
  2445 
  2446 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2447   only the theorems proved on ZF.ML;
  2448 
  2449 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2450   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2451   disjointness reasoning but breaking a few old proofs.
  2452 
  2453 * ZF/Update: new theory of function updates
  2454     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2455   may also be iterated as in f(a:=b,c:=d,...);
  2456 
  2457 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2458 
  2459 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2460   [previously, this check worked only if the rewrite rule was unconditional]
  2461   Now rew can involve either definitions or equalities (either == or =).
  2462 
  2463 * case_tac provided for compatibility with HOL
  2464     (like the old excluded_middle_tac, but with subgoals swapped)
  2465 
  2466 
  2467 *** Internal programming interfaces ***
  2468 
  2469 * Pure: several new basic modules made available for general use, see
  2470 also src/Pure/README;
  2471 
  2472 * improved the theory data mechanism to support encapsulation (data
  2473 kind name replaced by private Object.kind, acting as authorization
  2474 key); new type-safe user interface via functor TheoryDataFun; generic
  2475 print_data function becomes basically useless;
  2476 
  2477 * removed global_names compatibility flag -- all theory declarations
  2478 are qualified by default;
  2479 
  2480 * module Pure/Syntax now offers quote / antiquote translation
  2481 functions (useful for Hoare logic etc. with implicit dependencies);
  2482 see HOL/ex/Antiquote for an example use;
  2483 
  2484 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2485 cterm -> thm;
  2486 
  2487 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2488 subgoal;
  2489 
  2490 * Display.print_goals function moved to Locale.print_goals;
  2491 
  2492 * standard print function for goals supports current_goals_markers
  2493 variable for marking begin of proof, end of proof, start of goal; the
  2494 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2495 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2496 for example;
  2497 
  2498 
  2499 
  2500 New in Isabelle98 (January 1998)
  2501 --------------------------------
  2502 
  2503 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2504 
  2505 * changed lexical syntax of terms / types: dots made part of long
  2506 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2507 
  2508 * simpset (and claset) reference variable replaced by functions
  2509 simpset / simpset_ref;
  2510 
  2511 * no longer supports theory aliases (via merge) and non-trivial
  2512 implicit merge of thms' signatures;
  2513 
  2514 * most internal names of constants changed due to qualified names;
  2515 
  2516 * changed Pure/Sequence interface (see Pure/seq.ML);
  2517 
  2518 
  2519 *** General Changes ***
  2520 
  2521 * hierachically structured name spaces (for consts, types, axms, thms
  2522 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2523 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2524 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2525 long_names for fully qualified output names; NOTE: ML programs
  2526 (special tactics, packages etc.) referring to internal names may have
  2527 to be adapted to cope with fully qualified names; in case of severe
  2528 backward campatibility problems try setting 'global_names' at compile
  2529 time to have enrything declared within a flat name space; one may also
  2530 fine tune name declarations in theories via the 'global' and 'local'
  2531 section;
  2532 
  2533 * reimplemented the implicit simpset and claset using the new anytype
  2534 data filed in signatures; references simpset:simpset ref etc. are
  2535 replaced by functions simpset:unit->simpset and
  2536 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2537 to patch your ML files accordingly;
  2538 
  2539 * HTML output now includes theory graph data for display with Java
  2540 applet or isatool browser; data generated automatically via isatool
  2541 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2542 
  2543 * defs may now be conditional; improved rewrite_goals_tac to handle
  2544 conditional equations;
  2545 
  2546 * defs now admits additional type arguments, using TYPE('a) syntax;
  2547 
  2548 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2549 creates a new theory node; implicit merge of thms' signatures is
  2550 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2551 transfer:theory->thm->thm in (rare) cases;
  2552 
  2553 * improved handling of draft signatures / theories; draft thms (and
  2554 ctyps, cterms) are automatically promoted to real ones;
  2555 
  2556 * slightly changed interfaces for oracles: admit many per theory, named
  2557 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2558 
  2559 * print_goals: optional output of const types (set show_consts and
  2560 show_types);
  2561 
  2562 * improved output of warnings (###) and errors (***);
  2563 
  2564 * subgoal_tac displays a warning if the new subgoal has type variables;
  2565 
  2566 * removed old README and Makefiles;
  2567 
  2568 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2569 
  2570 * removed obsolete init_pps and init_database;
  2571 
  2572 * deleted the obsolete tactical STATE, which was declared by
  2573     fun STATE tacfun st = tacfun st st;
  2574 
  2575 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2576 (which abbreviates $HOME);
  2577 
  2578 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2579 use isatool fixseq to adapt your ML programs (this works for fully
  2580 qualified references to the Sequence structure only!);
  2581 
  2582 * use_thy no longer requires writable current directory; it always
  2583 reloads .ML *and* .thy file, if either one is out of date;
  2584 
  2585 
  2586 *** Classical Reasoner ***
  2587 
  2588 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2589 tactics that use classical reasoning to simplify a subgoal without
  2590 splitting it into several subgoals;
  2591 
  2592 * Safe_tac: like safe_tac but uses the default claset;
  2593 
  2594 
  2595 *** Simplifier ***
  2596 
  2597 * added simplification meta rules:
  2598     (asm_)(full_)simplify: simpset -> thm -> thm;
  2599 
  2600 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2601 logics (again);
  2602 
  2603 * added prems argument to simplification procedures;
  2604 
  2605 * HOL, FOL, ZF: added infix function `addsplits':
  2606   instead of `<simpset> setloop (split_tac <thms>)'
  2607   you can simply write `<simpset> addsplits <thms>'
  2608 
  2609 
  2610 *** Syntax ***
  2611 
  2612 * TYPE('a) syntax for type reflection terms;
  2613 
  2614 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2615 
  2616 * pretty printer: changed order of mixfix annotation preference (again!);
  2617 
  2618 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2619 
  2620 
  2621 *** HOL ***
  2622 
  2623 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2624   with `addloop' of the simplifier to faciliate case splitting in premises.
  2625 
  2626 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2627 
  2628 * HOL/Auth: new protocol proofs including some for the Internet
  2629   protocol TLS;
  2630 
  2631 * HOL/Map: new theory of `maps' a la VDM;
  2632 
  2633 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2634 cancelling out common nat summands from =, <, <= (in)equalities, or
  2635 differences; simplification procedures nat_cancel_factor for
  2636 cancelling common factor from =, <, <= (in)equalities over natural
  2637 sums; nat_cancel contains both kinds of procedures, it is installed by
  2638 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2639 
  2640 * HOL/simplifier: terms of the form
  2641   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2642   are rewritten to
  2643   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2644   and those of the form
  2645   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2646   are rewritten to
  2647   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2648 
  2649 * HOL/datatype
  2650   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2651 
  2652   P(t_case f1 ... fn x) =
  2653      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2654         ...
  2655        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2656      )
  2657 
  2658   and a theorem `split_t_case_asm' of the form
  2659 
  2660   P(t_case f1 ... fn x) =
  2661     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2662         ...
  2663        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2664      )
  2665   which can be added to a simpset via `addsplits'. The existing theorems
  2666   expand_list_case and expand_option_case have been renamed to
  2667   split_list_case and split_option_case.
  2668 
  2669 * HOL/Arithmetic:
  2670   - `pred n' is automatically converted to `n-1'.
  2671     Users are strongly encouraged not to use `pred' any longer,
  2672     because it will disappear altogether at some point.
  2673   - Users are strongly encouraged to write "0 < n" rather than
  2674     "n ~= 0". Theorems and proof tools have been modified towards this
  2675     `standard'.
  2676 
  2677 * HOL/Lists:
  2678   the function "set_of_list" has been renamed "set" (and its theorems too);
  2679   the function "nth" now takes its arguments in the reverse order and
  2680   has acquired the infix notation "!" as in "xs!n".
  2681 
  2682 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2683 
  2684 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2685   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2686 
  2687 * HOL/record: extensible records with schematic structural subtyping
  2688 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2689 still lacks various theorems and concrete record syntax;
  2690 
  2691 
  2692 *** HOLCF ***
  2693 
  2694 * removed "axioms" and "generated by" sections;
  2695 
  2696 * replaced "ops" section by extended "consts" section, which is capable of
  2697   handling the continuous function space "->" directly;
  2698 
  2699 * domain package:
  2700   . proves theorems immediately and stores them in the theory,
  2701   . creates hierachical name space,
  2702   . now uses normal mixfix annotations (instead of cinfix...),
  2703   . minor changes to some names and values (for consistency),
  2704   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2705   . separator between mutual domain defs: changed "," to "and",
  2706   . improved handling of sort constraints;  now they have to
  2707     appear on the left-hand side of the equations only;
  2708 
  2709 * fixed LAM <x,y,zs>.b syntax;
  2710 
  2711 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2712 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2713 
  2714 
  2715 *** FOL and ZF ***
  2716 
  2717 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2718   with `addloop' of the simplifier to faciliate case splitting in premises.
  2719 
  2720 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2721 in HOL, they strip ALL and --> from proved theorems;
  2722 
  2723 
  2724 
  2725 New in Isabelle94-8 (May 1997)
  2726 ------------------------------
  2727 
  2728 *** General Changes ***
  2729 
  2730 * new utilities to build / run / maintain Isabelle etc. (in parts
  2731 still somewhat experimental); old Makefiles etc. still functional;
  2732 
  2733 * new 'Isabelle System Manual';
  2734 
  2735 * INSTALL text, together with ./configure and ./build scripts;
  2736 
  2737 * reimplemented type inference for greater efficiency, better error
  2738 messages and clean internal interface;
  2739 
  2740 * prlim command for dealing with lots of subgoals (an easier way of
  2741 setting goals_limit);
  2742 
  2743 
  2744 *** Syntax ***
  2745 
  2746 * supports alternative (named) syntax tables (parser and pretty
  2747 printer); internal interface is provided by add_modesyntax(_i);
  2748 
  2749 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2750 be used in conjunction with the Isabelle symbol font; uses the
  2751 "symbols" syntax table;
  2752 
  2753 * added token_translation interface (may translate name tokens in
  2754 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2755 the current print_mode); IMPORTANT: user print translation functions
  2756 are responsible for marking newly introduced bounds
  2757 (Syntax.mark_boundT);
  2758 
  2759 * token translations for modes "xterm" and "xterm_color" that display
  2760 names in bold, underline etc. or colors (which requires a color
  2761 version of xterm);
  2762 
  2763 * infixes may now be declared with names independent of their syntax;
  2764 
  2765 * added typed_print_translation (like print_translation, but may
  2766 access type of constant);
  2767 
  2768 
  2769 *** Classical Reasoner ***
  2770 
  2771 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2772 some limitations.  Blast_tac...
  2773   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2774   + ignores elimination rules that don't have the correct format
  2775         (the conclusion MUST be a formula variable)
  2776   + ignores types, which can make HOL proofs fail
  2777   + rules must not require higher-order unification, e.g. apply_type in ZF
  2778     [message "Function Var's argument not a bound variable" relates to this]
  2779   + its proof strategy is more general but can actually be slower
  2780 
  2781 * substitution with equality assumptions no longer permutes other
  2782 assumptions;
  2783 
  2784 * minor changes in semantics of addafter (now called addaltern); renamed
  2785 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2786 (and access functions for it);
  2787 
  2788 * improved combination of classical reasoner and simplifier:
  2789   + functions for handling clasimpsets
  2790   + improvement of addss: now the simplifier is called _after_ the
  2791     safe steps.
  2792   + safe variant of addss called addSss: uses safe simplifications
  2793     _during_ the safe steps. It is more complete as it allows multiple
  2794     instantiations of unknowns (e.g. with slow_tac).
  2795 
  2796 *** Simplifier ***
  2797 
  2798 * added interface for simplification procedures (functions that
  2799 produce *proven* rewrite rules on the fly, depending on current
  2800 redex);
  2801 
  2802 * ordering on terms as parameter (used for ordered rewriting);
  2803 
  2804 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2805 
  2806 * the solver is now split into a safe and an unsafe part.
  2807 This should be invisible for the normal user, except that the
  2808 functions setsolver and addsolver have been renamed to setSolver and
  2809 addSolver; added safe_asm_full_simp_tac;
  2810 
  2811 
  2812 *** HOL ***
  2813 
  2814 * a generic induction tactic `induct_tac' which works for all datatypes and
  2815 also for type `nat';
  2816 
  2817 * a generic case distinction tactic `exhaust_tac' which works for all
  2818 datatypes and also for type `nat';
  2819 
  2820 * each datatype comes with a function `size';
  2821 
  2822 * patterns in case expressions allow tuple patterns as arguments to
  2823 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2824 
  2825 * primrec now also works with type nat;
  2826 
  2827 * recdef: a new declaration form, allows general recursive functions to be
  2828 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2829 
  2830 * the constant for negation has been renamed from "not" to "Not" to
  2831 harmonize with FOL, ZF, LK, etc.;
  2832 
  2833 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2834 infinite lists;
  2835 
  2836 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2837 
  2838 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2839 problems in commutative rings, using axiomatic type classes for + and *;
  2840 
  2841 * more examples in HOL/MiniML and HOL/Auth;
  2842 
  2843 * more default rewrite rules for quantifiers, union/intersection;
  2844 
  2845 * a new constant `arbitrary == @x.False';
  2846 
  2847 * HOLCF/IOA replaces old HOL/IOA;
  2848 
  2849 * HOLCF changes: derived all rules and arities
  2850   + axiomatic type classes instead of classes
  2851   + typedef instead of faking type definitions
  2852   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2853   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2854   + eliminated the types void, one, tr
  2855   + use unit lift and bool lift (with translations) instead of one and tr
  2856   + eliminated blift from Lift3.thy (use Def instead of blift)
  2857   all eliminated rules are derived as theorems --> no visible changes ;
  2858 
  2859 
  2860 *** ZF ***
  2861 
  2862 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2863 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2864 as ZF_cs addSIs [equalityI];
  2865 
  2866 
  2867 
  2868 New in Isabelle94-7 (November 96)
  2869 ---------------------------------
  2870 
  2871 * allowing negative levels (as offsets) in prlev and choplev;
  2872 
  2873 * super-linear speedup for large simplifications;
  2874 
  2875 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2876 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2877 FAIL); can suppress it using the command Delsimps (ex_simps @
  2878 all_simps); De Morgan laws are also now included, by default;
  2879 
  2880 * improved printing of ==>  :  ~:
  2881 
  2882 * new object-logic "Sequents" adds linear logic, while replacing LK
  2883 and Modal (thanks to Sara Kalvala);
  2884 
  2885 * HOL/Auth: correctness proofs for authentication protocols;
  2886 
  2887 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2888 examples on HOL/Auth);
  2889 
  2890 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2891 the rewriter and classical reasoner simultaneously;
  2892 
  2893 * function uresult no longer returns theorems in "standard" format;
  2894 regain previous version by: val uresult = standard o uresult;
  2895 
  2896 
  2897 
  2898 New in Isabelle94-6
  2899 -------------------
  2900 
  2901 * oracles -- these establish an interface between Isabelle and trusted
  2902 external reasoners, which may deliver results as theorems;
  2903 
  2904 * proof objects (in particular record all uses of oracles);
  2905 
  2906 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2907 
  2908 * "constdefs" section in theory files;
  2909 
  2910 * "primrec" section (HOL) no longer requires names;
  2911 
  2912 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2913 
  2914 
  2915 
  2916 New in Isabelle94-5
  2917 -------------------
  2918 
  2919 * reduced space requirements;
  2920 
  2921 * automatic HTML generation from theories;
  2922 
  2923 * theory files no longer require "..." (quotes) around most types;
  2924 
  2925 * new examples, including two proofs of the Church-Rosser theorem;
  2926 
  2927 * non-curried (1994) version of HOL is no longer distributed;
  2928 
  2929 
  2930 
  2931 New in Isabelle94-4
  2932 -------------------
  2933 
  2934 * greatly reduced space requirements;
  2935 
  2936 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2937 
  2938 * searchable theorem database (see the section "Retrieving theorems" on
  2939 page 8 of the Reference Manual);
  2940 
  2941 * new examples, including Grabczewski's monumental case study of the
  2942 Axiom of Choice;
  2943 
  2944 * The previous version of HOL renamed to Old_HOL;
  2945 
  2946 * The new version of HOL (previously called CHOL) uses a curried syntax
  2947 for functions.  Application looks like f a b instead of f(a,b);
  2948 
  2949 * Mutually recursive inductive definitions finally work in HOL;
  2950 
  2951 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2952 translates to the operator "split";
  2953 
  2954 
  2955 
  2956 New in Isabelle94-3
  2957 -------------------
  2958 
  2959 * new infix operator, addss, allowing the classical reasoner to
  2960 perform simplification at each step of its search.  Example:
  2961         fast_tac (cs addss ss)
  2962 
  2963 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2964 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2965 look like (a,b) instead of <a,b>;
  2966 
  2967 * PLEASE NOTE: CHOL will eventually replace HOL!
  2968 
  2969 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2970 It translates to the operator "split".  A new theory of integers is available;
  2971 
  2972 * In ZF, integer numerals now denote two's-complement binary integers.
  2973 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2974 
  2975 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2976 of the Axiom of Choice;
  2977 
  2978 
  2979 
  2980 New in Isabelle94-2
  2981 -------------------
  2982 
  2983 * Significantly faster resolution;
  2984 
  2985 * the different sections in a .thy file can now be mixed and repeated
  2986 freely;
  2987 
  2988 * Database of theorems for FOL, HOL and ZF.  New
  2989 commands including qed, qed_goal and bind_thm store theorems in the database.
  2990 
  2991 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2992 a given theory (thms_of), or find out what theory a theorem was proved in
  2993 (theory_of_thm);
  2994 
  2995 * Bugs fixed in the inductive definition and datatype packages;
  2996 
  2997 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2998 and HOL_dup_cs obsolete;
  2999 
  3000 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3001 have been removed;
  3002 
  3003 * Simpler definition of function space in ZF;
  3004 
  3005 * new results about cardinal and ordinal arithmetic in ZF;
  3006 
  3007 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3008 types;
  3009 
  3010 
  3011 $Id$